gbss14.0 optional feature description

GBSS14.0 Optional Feature Description

Issue V0.5

Date 2011-08-30

HUAWEI TECHNOLOGIES CO., LTD.

Issue V0.5 (2011-08-30) Huawei Proprietary and Confidential

Copyright © Huawei Technologies Co., Ltd

2

Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior

written consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their respective

holders.

Notice

The purchased products, services and features are stipulated by the commercial contract made between

Huawei and the customer. All or partial products, services and features described in this document may not

be within the purchased scope or the usage scope. Unless otherwise agreed by the contract, all

statements, information, and recommendations in this document are provided "AS IS" without warranties,

guarantees or representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the

preparation of this document to ensure accuracy of the contents, but all statements, information, and

recommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

Bantian, Longgang

Shenzhen 518129

People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

http://www.huawei.com/

mailto:[email protected]

GBSS14.0 Optional Feature Description Contents



iii

Contents

1 Voice&Service................................................................................................................................ 1

1.1 Crystal Voice .................................................................................................................................................... 1

1.1.1 GBFD-113301 Enhanced Full Rate ........................................................................................................ 1

1.1.2 GBFD-115601 Automatic Level Control (ALC) .................................................................................... 2

1.1.3 GBFD-115602 Acoustic Echo Cancellation (AEC) ................................................................................ 5

1.1.4 GBFD-115603 Automatic Noise Restraint (ANR) .................................................................................. 6

1.1.5 GBFD-115701 TFO ................................................................................................................................ 7

1.1.6 GBFD-115702 TrFO ............................................................................................................................... 9

1.1.7 GBFD-115703 Automatic Noise Compensation (ANC) ....................................................................... 11

1.1.8 GBFD-115704 Enhancement Packet Loss Concealment (EPLC) ......................................................... 12

1.1.9 GBFD-115711 EVAD ........................................................................................................................... 14

1.1.10 GBFD-116801 Voice Quality Index (VQI) ......................................................................................... 15

1.1.11 GBFD-115708 Um Interface Speech Frame Repairing ....................................................................... 16

1.2 AMR Package................................................................................................................................................. 17

1.2.1 GBFD-115501 AMR FR ....................................................................................................................... 17

1.2.2 GBFD-115502 AMR HR ...................................................................................................................... 19

1.2.3 GBFD-115503 AMR Power Control ..................................................................................................... 21

1.2.4 GBFD-115504 AMR FR/HR Dynamic Adjustment .............................................................................. 22

1.2.5 GBFD-115505 AMR Radio Link Timer ............................................................................................... 23

1.2.6 GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment .................................................... 24

1.2.7 GBFD-115507 WB AMR...................................................................................................................... 26

1.3 Voice Capacity ................................................................................................................................................ 27

1.3.1 GBFD-113401 Half Rate Speech .......................................................................................................... 27

1.3.2 GBFD-113402 Dynamic Adjustment Between FR and HR .................................................................. 28

1.3.3 GBFD-115522 Dynamic HR/FR Adaptation ........................................................................................ 30

1.3.4 GBFD-115830 VAMOS ........................................................................................................................ 31

1.3.5 GBFD-115831 Mute SAIC MS Identification ...................................................................................... 33

1.3.6 GBFD-115832 VAMOS Call Drop Solution ......................................................................................... 34

1.4 Cell Broadcast ................................................................................................................................................ 35

1.4.1 GBFD-113601 Short Message Service Cell Broadcast (TS23) ............................................................. 35

1.4.2 GBFD-113602 Simplified Cell Broadcast ............................................................................................ 36

1.5 GSM Trunking ............................................................................................................................................... 38

1.5.1 GBFD-510301 Public Voice Group Call Service .................................................................................. 38




iv

1.5.2 GBFD-510303 Late Group Channel Assignment ................................................................................. 39

1.5.3 GBFD-510305 Single Channel Group Call Originating ....................................................................... 40

1.5.4 GBFD-510306 Talker Identification ..................................................................................................... 41

1.5.5 GBFD-510307 Group Call EMLPP ...................................................................................................... 42

1.5.6 GBFD-510308 Fast Group Call Setup .................................................................................................. 43

1.5.7 GBFD-510309 Group Call Reliability Enhancing ................................................................................ 44

1.5.8 GBFD-510302 Public Voice Broadcast Service .................................................................................... 46

1.5.9 GBFD-510304 Late Broadcast Channel Assignment ............................................................................ 47

1.5.10 GBFD-510310 GSM-T Relay ............................................................................................................. 48

1.6 LCS ................................................................................................................................................................ 49

1.6.1 GBFD-115401 NSS-based LCS (Cell ID + TA) ................................................................................... 49

1.6.2 GBFD-115402 BSS-based LCS (Cell ID + TA) ................................................................................... 50

1.6.3 GBFD-115403 Simple Mode LCS (Cell ID + TA) ............................................................................... 51

1.6.4 GBFD-115404 Lb Interface .................................................................................................................. 52

1.7 VIP Service..................................................................................................................................................... 54

1.7.1 GBFD-116001 Resource Reservation ................................................................................................... 54

1.7.2 GBFD-115001 Enhanced Multi Level Precedence and Preemption (EMLPP) ..................................... 55

1.7.3 GBFD-115002 Flow Control Based on Cell Priority ............................................................................ 57

1.7.4 GBFD-115003 Flow control based on User priority ............................................................................. 58

1.7.5 GBFD-119907 PS Service in Priority ................................................................................................... 59

2 Packet Service .............................................................................................................................. 61

2.1 PS Prime Service ............................................................................................................................................ 61

2.1.1 GBFD-114101 GPRS ............................................................................................................................ 61

2.1.2 GBFD-510001 Network Operation Mode I .......................................................................................... 62

2.1.3 GBFD-118901 CS-3/CS-4 .................................................................................................................... 64

2.1.4 GBFD-114201 EGPRS ......................................................................................................................... 65

2.1.5 GBFD-113101 PDCH Dynamic Adjustment ........................................................................................ 67

2.1.6 GBFD-510002 Gb Over FR .................................................................................................................. 69

2.1.7 GBFD-119201 11-Bit EGPRS Access .................................................................................................. 70

2.1.8 GBFD-119203 Extended Uplink TBF .................................................................................................. 71

2.1.9 GBFD-119204 Dynamically Adjusting the Uplink MCS Coding ......................................................... 72

2.1.10 GBFD-119205 Dynamically Adjusting the RRBP Frequency ............................................................ 73

2.1.11 GBFD-119302 Packet Channel Dispatching ....................................................................................... 74

2.1.12 GBFD-119303 Load Sharing .............................................................................................................. 76

2.1.13 GBFD-119501 Adaptive Adjustment of Uplink and Downlink Channels .......................................... 77

2.2 PS Service Enhancement ................................................................................................................................ 79

2.2.1 GBFD-119901 Streaming QoS(GBR) ................................................................................................... 79

2.2.2 GBFD-119902 QoS ARP&THP............................................................................................................ 80

2.2.3 GBFD-119904 PS Active Package Management .................................................................................. 81

2.2.4 GBFD-119905 PoC QoS ....................................................................................................................... 83

2.2.5 GBFD-119906 Conversational QoS ...................................................................................................... 84




v

2.2.6 GBFD-116201 Network-Controlled Cell Reselection (NC2) ............................................................... 86

2.2.7 GBFD-116301 Network Assisted Cell Change (NACC) ...................................................................... 87

2.2.8 GBFD-119801 Packet SI Status (PSI) ................................................................................................... 88

2.2.9 GBFD-119305 BSS Paging Coordination ............................................................................................. 89

2.2.10 GBFD-119502 PS Handover ............................................................................................................... 90

2.2.11 GBFD-119503 Early TBF Establishment ............................................................................................ 91

2.2.12 GBFD-119504 PS Power Control ....................................................................................................... 92

2.2.13 GBFD-119505 PDCH Dynamic Adjustment with Two Thresholds .................................................... 94

2.2.14 GBFD-119506 GPRS/EGPRS Time slot multiplexing priority .......................................................... 95

2.2.15 GBFD-119401 Extended Dynamic Allocation (EDA) ........................................................................ 96

2.2.16 GBFD-119402 MS High Multislot Classes ......................................................................................... 97

2.2.17 GBFD-114151 DTM ........................................................................................................................... 98

2.2.18 GBFD-119403 Class11 DTM ........................................................................................................... 100

2.2.19 GBFD-119404 HMC DTM ............................................................................................................... 102

2.2.20 GBFD-119405 14.4kbit/s Circuit Switched Data .............................................................................. 103

2.2.21 GBFD-119406 High Speed Circuit Switched Data ........................................................................... 104

2.2.22 GBFD-119407 Active TBF Allocation .............................................................................................. 106

2.3 EDGE Evolution .......................................................................................................................................... 108

2.3.1 GBFD-510801 MSRD ........................................................................................................................ 108

2.3.2 GBFD-510802 Dual Carriers in Downlink ......................................................................................... 109

2.3.3 GBFD-510803 Uplink EGPRS2-A ..................................................................................................... 110

2.3.4 GBFD-510804 Downlink EGPRS2-A ................................................................................................ 112

2.3.5 GBFD-510805 Latency Reduction ..................................................................................................... 114

3 Smart MBB ................................................................................................................................. 117

3.1 Intelligent Channel ....................................................................................................................................... 117

3.1.1 GBFD-511603 IM Service Efficiency Improvement .......................................................................... 117

3.1.2 GBFD-511604 Web Browsing Service Efficiency Improvement ....................................................... 118

3.1.3 GBFD-511605 Email Service Efficiency Improvement ..................................................................... 120

3.1.4 GBFD-511606 Streaming Media Service Resource Balancing ........................................................... 121

3.1.5 GBFD-511607 P2P Resource Balancing ............................................................................................. 122

3.2 Smartphone Solution .................................................................................................................................... 124

3.2.1 GBFD-511501 Multiple CCCHs ......................................................................................................... 124

3.2.2 GBFD-511502 Layered Paging ........................................................................................................... 125

3.2.3 GBFD-511503 Dynamic Multiple CCCH ........................................................................................... 126

4 Green ........................................................................................................................................... 128

4.1 Power Consumption Saving ......................................................................................................................... 128

4.1.1 GBFD-117601 HUAWEI III Power Control Algorithm ..................................................................... 128

4.1.2 GBFD-117602 Active Power Control ................................................................................................. 129

4.1.3 GBFD-118103 Network Support SAIC .............................................................................................. 131

4.1.4 GBFD-114801 Discontinuous Transmission (DTX)-Downlink .......................................................... 132

4.1.5 GBFD-114803 Discontinuous Transmission (DTX)-Uplink .............................................................. 133




vi

4.1.6 GBFD-111602 TRX Power Amplifier Intelligent Shutdown .............................................................. 135

4.1.7 GBFD-111603 TRX Power Amplifier Intelligent Shutdown on Timeslot Level ................................ 136

4.1.8 GBFD-111604 Intelligent Combiner Bypass ...................................................................................... 137

4.1.9 GBFD-111605 Active Backup Power Control .................................................................................... 138

4.1.10 GBFD-111606 Power Optimization Based on Channel Type ........................................................... 140

4.1.11 GBFD-111608 PSU Smart Control ................................................................................................... 141

4.1.12 GBFD-111609 Enhanced BCCH Power Consumption Optimization ............................................... 142

4.1.13 GBFD-111610 Dynamic Cell Power Off .......................................................................................... 143

4.1.14 GBFD-111611 TRX Working Voltage Adjustment ........................................................................... 145

4.1.15 GBFD-111612 Multi-Carrier Intelligent Voltage Regulation ............................................................ 146

5 Topology&Transmission ......................................................................................................... 148

5.1 Transmission Efficiency ............................................................................................................................... 148

5.1.1 GBFD-116701 16Kbit RSL and OML on Abis Interface .................................................................... 148

5.1.2 GBFD-117301 Flex Abis .................................................................................................................... 149

5.1.3 GBFD-117702 BTS Local Switch ...................................................................................................... 150

5.1.4 GBFD-118401 Abis Transmission Optimization ................................................................................ 153

5.1.5 GBFD-112013 Abis Congestion Trigger HR Distribution .................................................................. 155

5.1.6 GBFD-116901 Flex Ater ..................................................................................................................... 157

5.1.7 GBFD-117701 BSC Local Switch ...................................................................................................... 158

5.1.8 GBFD-116902 Ater Compression Transmission ................................................................................. 161

5.1.9 GBFD-511201 2G/3G Co-Transmission by TDM Switching ............................................................. 163

5.1.10 GBFD-115301 Local Multiple Signaling Points ............................................................................... 165

5.2 IP Transmission ............................................................................................................................................ 166

5.2.1 GBFD-118606 Clock Over IP ............................................................................................................. 166

5.2.2 GBFD-118620 Clock over IP support 1588v2 .................................................................................... 168

5.2.3 GBFD-118202 Synchronous Ethernet................................................................................................. 170

5.2.4 GBFD-118601 Abis over IP ................................................................................................................ 171

5.2.5 GBFD-118611 Abis IP over E1/T1 ..................................................................................................... 175

5.2.6 GBFD-118604 Abis MUX .................................................................................................................. 177

5.2.7 GBFD-118612 Abis IPHC .................................................................................................................. 178

5.2.8 GBFD-118602 A over IP ..................................................................................................................... 180

5.2.9 GBFD-118622 A IP over E1/T1 .......................................................................................................... 183

5.2.10 GBFD-118610 UDP MUX for A Transmission ................................................................................ 185

5.2.11 GBFD-118623 TDM/IP Dual Transmission over A Interface ........................................................... 186

5.2.12 GBFD-118603 Gb over IP ................................................................................................................ 188

5.2.13 GBFD-118605 IP QoS ...................................................................................................................... 190

5.2.14 GBFD-118630 Ethernet OAM .......................................................................................................... 193

5.3 Satellite Transmission .................................................................................................................................. 195

5.3.1 GBFD-113901 Satellite Transmission over Abis Interface ................................................................. 195

5.3.2 GBFD-113902 Satellite Transmission over A Interface ...................................................................... 196

5.3.3 GBFD-113903 Satellite Transmission over Ater Interface .................................................................. 197




vii

5.3.4 GBFD-113905 Satellite Transmission over Gb Interface.................................................................... 198

5.4 RAN Sharing ................................................................................................................................................ 199

5.4.1 GBFD-118701 RAN Sharing .............................................................................................................. 199

5.4.2 GBFD-118704 Abis Independent Transmission .................................................................................. 200

5.4.3 GBFD-118702 MOCN Shared Cell .................................................................................................... 202

5.4.4 GBFD-118703 IMSI-Based Handover ................................................................................................ 203

6 Site Solution ............................................................................................................................... 205

6.1 PICO Solution .............................................................................................................................................. 205

6.1.1 GBFD-510601 PICO Automatic Configuration and Planning ............................................................ 205

6.1.2 GBFD-510602 PICO Synchronization................................................................................................ 206

6.1.3 GBFD-510603 PICO Dual-band Auto-planning ................................................................................. 207

6.1.4 GBFD-510604 PICO USB Encryption ............................................................................................... 209

6.1.5 GBFD-510605 PICO Access Control List (ACL) ............................................................................... 210

6.1.6 GBFD-510606 PICO Sleeping Mode ................................................................................................. 210

6.1.7 GBFD-510607 PICO Automatic Optimization ................................................................................... 211

6.1.8 GBFD-510608 PICO Transceiver Redundancy .................................................................................. 212

6.2 EasyGSM Solution ....................................................................................................................................... 213

6.2.1 GBFD-510701 Compact BTS Automatic Configuration and Planning .............................................. 213

6.2.2 GBFD-510702 Compact BTS Automatic Capacity Planning ............................................................. 215

6.2.3 GBFD-510704 Compact BTS Automatic Neighbor Cell Planning and Optimization ........................ 216

6.2.4 GBFD-510705 Compact BTS Timing Power Off ............................................................................... 217

6.2.5 GBFD-510706 Local User Management ............................................................................................ 218

6.2.6 GBFD-111613 Weather Adaptive Power Management ....................................................................... 220

6.3 Auxiliary Equipment Management .............................................................................................................. 222

6.3.1 GBFD-510710 Intelligent Battery Management ................................................................................. 222

7 Network Performance .............................................................................................................. 224

7.1 Coverage Enhancement ................................................................................................................................ 224

7.1.1 GBFD-115901 PBT(Power Boost Technology) .................................................................................. 224

7.1.2 GBFD-115902 Transmit Diversity ...................................................................................................... 225

7.1.3 GBFD-115903 4-Way Receiver Diversity .......................................................................................... 226

7.1.4 GBFD-118101 Dynamic Transmit Diversity ...................................................................................... 227

7.1.5 GBFD-118102 Dynamic PBT (Power Boost Technology) ................................................................. 228

7.1.6 GBFD-118104 Enhanced EDGE Coverage ........................................................................................ 230

7.1.7 GBFD-118106 Dynamic Power Sharing ............................................................................................. 231

7.1.8 GBFD-114001 Extended Cell ............................................................................................................. 233

7.2 Capacity Improvement ................................................................................................................................. 235

7.2.1 GBFD-113201 Concentric Cell ........................................................................................................... 235

7.2.2 GBFD-114501 Co-BCCH Cell ........................................................................................................... 236

7.2.3 GBFD-114402 Enhanced Dual-band Network ................................................................................... 238

7.2.4 GBFD-117001 Flex MAIO ................................................................................................................. 239

7.2.5 GBFD-115801 ICC ............................................................................................................................. 240




viii

7.2.6 GBFD-115821 EICC ........................................................................................................................... 241

7.2.7 GBFD-113701 Frequency Hopping (RF hopping, baseband hopping) ............................................... 243

7.2.8 GBFD-113702 BCCH Carrier Frequency Hopping ............................................................................ 244

7.2.9 GBFD-113703 Antenna Frequency Hopping ...................................................................................... 245

7.2.10 GBFD-118001 BCCH Dense Frequency Multiplexing..................................................................... 247

7.2.11 GBFD-117002 IBCA (Interference Based Channel Allocation) ....................................................... 248

7.2.12 GBFD-118201 Soft-Synchronized Network ..................................................................................... 250

7.2.13 GBFD-510401 BTS GPS Synchronization ....................................................................................... 252

7.2.14 GBFD-113706 Mega BSC ................................................................................................................ 254

7.3 High Speed Mobility .................................................................................................................................... 255

7.3.1 GBFD-510101 Automatic Frequency Correction (AFC) .................................................................... 255

7.3.2 GBFD-510102 Fast Move Handover .................................................................................................. 257

7.3.3 GBFD-510103 Chain Cell Handover .................................................................................................. 258

7.3.4 GBFD-510104 Multi-site Cell ............................................................................................................ 259

7.3.5 GBFD-510105 PS AFC ....................................................................................................................... 260

7.4 Intra-System Mobility Management ............................................................................................................ 262

7.4.1 GBFD-510501 HUAWEI II Handover ............................................................................................... 262

7.4.2 GBFD-510502 Handover Re-establishment ....................................................................................... 263

7.4.3 GBFD-117501 Enhanced Measurement Report (EMR) ..................................................................... 264

7.4.4 GBFD-117101 BTS Power Lift for Handover .................................................................................... 266

7.5 GSM & WCDMA Interoperability ............................................................................................................... 267

7.5.1 GBFD-114301 GSM/WCDMA Interoperability ................................................................................. 267

7.5.2 GBFD-114321 GSM/WCDMA Service Based Handover .................................................................. 268

7.5.3 GBFD-114322 GSM/WCDMA Load Based Handover ...................................................................... 269

7.5.4 GBFD-114323 GSM/WCDMA Cell Reselection Based on MS State ................................................ 270

7.5.5 GBFD-114325 Fast WCDMA Reselection at 2G CS Call Release ..................................................... 272

7.5.6 GBFD-511101 Load Based Handover Enhancement on Iur-g ............................................................ 273

7.5.7 GBFD-511102 NACC Procedure Optimization Based on Iur-g between GSM and WCDMA .......... 274

7.5.8 GBFD-511103 GSM and WCDMA Load Balancing Based on Iur-g ................................................. 276

7.5.9 GBFD-511104 GSM and WCDMA Traffic Steering Based on Iur-g .................................................. 278

7.6 GSM & LTE Interoperability ....................................................................................................................... 279

7.6.1 GBFD-511301 Cell Reselection Between GSM and LTE .................................................................. 279

7.6.2 GBFD-511302 PS Handover Between GSM and LTE Based on Coverage ........................................ 281

7.6.3 GBFD-511303 PS Handover Between GSM and LTE Based on Quality ........................................... 282

7.6.4 GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load ....................................... 284

7.6.5 GBFD-511305 PS Handover Between GSM and LTE Based on Mode Priority................................. 285

7.6.6 GBFD-511306 GSM/LTE Service Based PS Handover ..................................................................... 287

7.6.7 GBFD-511307 eNC2 Between GSM and LTE ................................................................................... 289

7.6.8 GBFD-511308 eNACC Between GSM and LTE ................................................................................ 290

7.6.9 GBFD-511309 SRVCC ....................................................................................................................... 291

7.6.10 GBFD-511310 Multi Technology Neighbour Cell Based Handover ................................................ 293

7.6.11 GBFD-511312 Fast LTE Reselection at 2G CS Call Release ........................................................... 294




ix

7.6.12 GBFD-511313 CSFB ........................................................................................................................ 295

7.7 GSM & TD-SCDMA Interoperability .......................................................................................................... 296

7.7.1 GBFD-114302 GSM/TD-SCDMA Interoperability ............................................................................ 296

7.7.2 GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA ........................................................ 297

7.7.3 GBFD-511402 Radio Resource Reserved Handover Between GSM/TD-SCDMA Based on Iur-g ... 299

7.7.4 GBFD-511403 Extended BCCH ......................................................................................................... 301

7.7.5 GBFD-511405 NC2 between GSM and TD-SCDMA ........................................................................ 302

8 Network Security ...................................................................................................................... 304

8.1 Security ........................................................................................................................................................ 304

8.1.1 GBFD-113501 A5/1 and A5/2 Ciphering Algorithm .......................................................................... 304

8.1.2 GBFD-113503 A5/3 Ciphering Algorithm .......................................................................................... 305

8.1.3 GBFD-113521 A5/1 Encryption Flow Optimization .......................................................................... 306

8.1.4 GBFD-113522 Encrypted Network Management ............................................................................... 307

8.1.5 GBFD-113524 BTS Integrated IPsec .................................................................................................. 309

8.1.6 GBFD-113526 BTS Supporting PKI .................................................................................................. 310

8.2 Reliability ..................................................................................................................................................... 312

8.2.1 GBFD-117801 Ring Topology ............................................................................................................ 312

8.2.2 GBFD-113801 TRX Cooperation ....................................................................................................... 315

8.2.3 GBFD-117401 MSC Pool ................................................................................................................... 316

8.2.4 GBFD-119701 SGSN Pool ................................................................................................................. 318

8.2.5 GBFD-116601 Abis Bypass ................................................................................................................ 320

8.2.6 GBFD-113721 Robust Air Interface Signalling .................................................................................. 321

8.2.7 GBFD-117803 Abis Transmission Backup ......................................................................................... 323

8.2.8 GBFD-113725 BSC Node Redundancy .............................................................................................. 324

8.2.9 GBFD-113726 TC POOL ................................................................................................................... 326

8.2.10 GBFD-113728 OML Backup ............................................................................................................ 327

8.2.11 GBFD-511002 Access Control Class (ACC) .................................................................................... 329

9 O&M Experience ....................................................................................................................... 331

9.1 O&M ............................................................................................................................................................ 331

9.1.1 GBFD-113729 Adaptive Transmission Link Blocking ....................................................................... 331

9.1.2 GBFD-114701 Semi-Permanent Connection ...................................................................................... 332

9.1.3 GBFD-116401 End-to-End MS Signaling Tracing ............................................................................. 335

9.1.4 GBFD-510901 GSM/3G Neighboring Cell Automatic Optimization ................................................. 336

9.2 Visualization & Data Collection ................................................................................................................... 338

9.2.1 GBFD-511701 Radio Measurement Data Interface for Navigation .................................................... 338

A Acronyms and Abbreviations ................................................................................................ 340

GBSS14.0 Optional Feature Description 1 Voice&Service



1

1 Voice&Service

1.1 Crystal Voice

1.1.1 GBFD-113301 Enhanced Full Rate

Availability

This feature was introduced in GBSS6.1.

Summary

The enhanced full rate (EFR) is an improved speech coding scheme. The quality of the speech

using EFR is better than that of the speech using FR.

Benefits

The user experience is improved because the voice quality in the EFR that uses the FR

channel resource approaches or even exceeds the voice quality in the ADPCM.

Description

The EFR is an improved speech coding scheme, which works at the rate of 12.2 kbit/s. The

quality of the voice using the FR channel resource in the EFR scheme approaches or even

exceeds the voice quality in the ADPCM scheme.

The EFR has good anti-noise performance. If the quality of the Um interface is good, you can

obtain the voice quality as good as the voice quality of the traditional wired telephone even if

there is a lot of background noise. Therefore, in the same air conditions, the subscriber can

perceive a better voice quality in the EFR than in the FR. In addition, the rate of the EFR is

lower than that of the FR (13 kbit/s). Therefore, the BER sensitivity of EFR is lower than that

of FR. In this manner, the data can be transmitted more reliably on the Abis interface, which

further improves the voice quality.

The EFR is also compatible with the highest rate of the narrowband AMR.

Enhancement

GBSS8.1




2

The EFR is introduced in GBSS8.1 and it is used in A over TDM transmission.

If the EFR feature is supported by the MS and the BSC but not supported by the MSC, the

EFR feature can be forcibly enabled on the BSC. In this manner, the used speech version is

shielded on the MSC side to avoid assignment or handover failure. The forced EFR function

is mainly applied in the areas with poor voice quality to improve the voice quality.

GBSS13.0

E-coder is introduced in GBSS13.0 and it is used in A over TDM transmission.

E-coder improves the EFR speech quality by using the enhanced spectrum technique and LSP

exact-calculate technique. In this way, E-coder increases the Mean Opinion Score (MOS) by

0.05 to 0.12. E-coder, however, introduces an algorithm delay of 5 ms to an EFR encoder. In

A over IP or TFO, E-coder is not supported.

Dependency

Dependency on BSC hardware

None

Dependency on BTS hardware

For the dependency on BTS hardware, see the GBSS14.0 Feature List.

Dependency on other GBSS features

None

Dependency on other NEs

The MS must support this feature.

1.1.2 GBFD-115601 Automatic Level Control (ALC)

Availability


Summary

This feature improves the user experience by checking the speech signals and then adjusting

the sound volume according to certain rules to keep the sound volume within the comfort

range.

Benefits

This feature can level out the difference between the sound volumes controlled by different

terminal manufacturers and therefore balance the receive level adaptation of subscribers in

different areas. In this manner, the subscriber can perceive better voice quality.




3

Description

The ALC algorithm automatically controls the receive level. By evaluating the receive level

of the input signal, the ALC feature controls the gains of the input signal, adjusts the output

signal to a certain target receive level, and maintains the stability and comprehensibility of the

signal receive level. Therefore, the subscriber can perceive comfort sound volume and good

voice quality.

The ALC has the following three modes:

Fixed level mode

The receive level of the signal is adjusted to a fixed target value based on the receive

level of the input voice.

Adaptive level mode

The receive level of the signal is adaptively adjusted to a value within a pre-determined

range based on the receive level of the input voice.

Fixed gain mode

The sound volume of the input signal is raised or lowered in a fixed proportion based on

the original sound volume.

Enhancement

GBSS8.1

The ALC algorithm performance is optimized.

GBSS12.0

The anti-clip (ACLP) algorithm is introduced in GBSS12.0.

The ACLP algorithm first corrects the signals with relatively great amplitude, quickly repairs

the speech wave, and then adjusts the volume. This improves the user experience.

The ACLP algorithm calculates the energy and spectrum characteristics of input speech

signals in real time. If too-high-level signals suffer from amplitude limiting and therefore

introduce distorted noises, the ACLP algorithm filters out distorted noises and performs

nonlinear volume adjustments to repair the signal wave according to spectrum characteristics.

In this manner, the user experience towards the voice quality is improved.




4

The volume is too

great and signals are

distorted due to

amplitude limiting.

Repair the distorted

signals.

The volume is

acceptable and the

distortion is decreased.

The volume is acceptable

but the distortion

remains.

The function of measuring and collecting statistics on signal levels online is introduced.

In GBSS12.0, the ALC algorithm can be used to measure and collect statistics on signal levels

online so that operators can monitor signal levels and learn the distribution of signal levels to

determine whether to enable the ALC algorithm for cells.

GBSS14.0

The level adjustment performance is optimized.

1. The speech tracing and adaptive capability of the ALC algorithm is optimized so that the

ALC algorithm becomes more responsive to situations where the volume changes

rapidly.

2. The internal dependencies on a fixed clipping threshold of the ACLP algorithm are

canceled so that the clipping threshold is adaptive to signal level changes.

3. A counter is provided to measure the signal level and the number of clipping

occurrences.

Dependency


None




5




This feature is mutually exclusive with the following features:

GBFD-118602 A over IP

GBFD-118622 A IP over E1/T1

GBFD-115701 TFO

GBFD-115702 TrFO

GBFD-117701 BSC Local Switch

GBFD-117702 BTS Local Switch


None

1.1.3 GBFD-115602 Acoustic Echo Cancellation (AEC)

Availability


Summary

The AEC identifies and cancels the acoustic echo after comparing the main features of

downlink voice and those of uplink voice after a period of delay.

Benefits

The AEC can reduce the acoustic echo generated by the MS, improving the network voice

quality and the user experience.

Description

The acoustic echo refers to the situation that the sound wave from one MS speaker is reflected

to the microphone (MIC) and the speech signal is sent back to the other MS because of the

characteristics of the MS. The acoustic echo generated by the MS is mainly related to the fact

that the MS speaker is too close to the MIC and therefore the sound wave attenuation is

insufficient.

During the call, the input voice from the CN is retained through the AEC module of the TC.

After a period of delay, the remote input voice from the CN is compared with the local voice

from the MS. If the codes of similar characteristics exist, it is considered that the local voice is

the echo of the remote voice. Then, the echo is handled nonlinearly and replaced with comfort

noise. In this manner, the original voice from the MIC is canceled, and therefore the user

experience is improved.

Enhancement

GBSS8.1




6

The AEC algorithm performance is optimized.

GBSS14.0

The accuracy of echo identification and cancellation is increased by 10%, which is calculated

by algorithm simulation.

The negative impact of echo cancellation on speech quality is decreased by 15%, which is

calculated by algorithm simulation.

A counter is provided to measure the number of echo occurrences.

Dependency


None







GBFD-115701 TFO

GBFD-115702 TrFO




None

1.1.4 GBFD-115603 Automatic Noise Restraint (ANR)

Availability


Summary

The ANR feature constrains the background noise during the call, reduces the receive level of

the noise, and therefore increases the signal-to-noise ratio (SNR).

Benefits

By suppressing the background noise during the call, the ANR makes the voice clear,

improving the user experience.




7

Description

The ANR distinguishes voice information from background noise based on the characteristics

of the input speech signal in different time domains and frequency domains. Then, the ANR

reduces and suppresses the background noise according to a certain algorithm. By reducing

the receive level of the noise and increasing the SNR, the ANR improves the user experience

without affecting the authentic voice.

Enhancement

GBSS8.1

The ALC algorithm performance is optimized.

GBSS14.0

The efficiency for suppressing noise of the same type for a second time and suppressing

unstable noise is improved.

The capability to distinguish voice signals and music is significantly improved.

A counter is provided to measure the number of times noise occurs at different levels.

Dependency


None







GBFD-115701 TFO

GBFD-115702 TrFO




None

1.1.5 GBFD-115701 TFO

Availability





8

Summary

With this feature, the TFO frames are transparently transmitted and encoding/decoding is

bypassed through the bit stealing scheme between the TCs at two ends. Therefore, the process

of encoding/decoding is reduced once.

Benefits

The speech signals deteriorate with each encoding/decoding. Therefore, using TFO to bypass

encoding/decoding can improve the voice quality. In the case of encoding/decoding of lower

rate, the voice quality is more evidently improved.

Description

For traditional mobile network system without TFO, the voice signal is encoded by the MS on

one side and transmitted over the radio interface. The signal is then decoded by the first TC

unit. The decoded PCM data flow is transmitted to the second TC unit through the 64 kbit/s

transmission link for encoding. After being encoded, the data is transmitted to the MS on the

other side over the radio interface for decoding. During the whole conversation, the speech is

transcoded twice, which is called tandem operation.

The TFO feature can reduce the speech signal degradation caused by tandem operation,

improving the voice quality. When the calling MS and the called MS use the same speech

version, the TFO link is established through the in-band signaling negotiation. In addition, the

least significant bit (or the second least significant bit) is stolen to seize the 8 kbit/s (or 16

kbit/s) sublink of the PCM transmission link for transparent transmission of TFO frames and

bypass TC encoding/decoding. In this manner, the speech signal is encoded at the MS

initiating the call and decoded at the MS terminating the call for only once. Therefore, the

degradation of the speech signals due to tandem operation is reduced and the voice quality is

improved. This process is called tandem free operation (TFO).

Enhancement

GBSS8.1

The AMR TFO is supported.

GBSS9.0

Transcoding

Function

Transcoding

Function

Transcoding Functions Bypassed

MS/UEMS/UE

PLMN A PLMN B

Encoding DecodingCompressed Speech

MS/UEMS/UE

PLMN A PLMN BTranscoding

Function

Encoding Decoding DecodingEncodingCompressed Speech Compressed SpeechITU-T G.711 A-Law/-Law

Transcoding Functions

Transcoding

Function




9

Conversion between the FR and HR in the TFO: During the negotiation of the TFO, if the

channel (FR or HR) used by the called party is different from the channel (HR or FR) used by

the calling party, the call is handed over from the FR channel to an HR channel before the

TFO. This feature improves the voice quality of the HR call.

Dependency


None




When a call using TFO feature, the following features cannot be used together:

GBFD-115601 Automatic Level Control (ALC)

GBFD-115602 Acoustic Echo Cancellation (AEC)

GBFD-115603 Automatic Noise Restraint (ANR)

GBFD-115703 Automatic Noise Compensation (ANC)

GBFD-115704 Enhancement Packet Loss Concealment (EPLC)

GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment

GBFD-117702 BTS Local Switch AMR Rate Adaptation Under BTS Local Switch

GBFD-117701 BSC Local Switch AMR Rate Adaptation Under BSC Local Switch


None

1.1.6 GBFD-115702 TrFO

Availability


Summary

With this feature, the calling MS and called MS use the same speech coding scheme.

Therefore, the speech signal is coded at the calling MS once and decoded at the called MS

once. This can solve the problem that the TRAU repeatedly codes and decodes the speech

signal.

Benefits

This feature provides the following benefits:

The TrFO feature enables the calling MS and called MS to use the same speech coding,

which prevents the repeated coding and decoding during the MS-MS call process. This

provides better speech quality for users.




10

In addition, the TRAU is not involved in the TrFO, saving the TC resources.

Description Repeated coding and decoding

In the traditional MS-MS call process where the TFO/TrFO is not adopted, the speech

signal is coded at the calling MS, transmitted on the Um interface, and is then decoded at

the first TRAU. The decoded PCM data flow is transmitted on the 64 kbit/s link to the

second TRAU for coding and is then transmitted on the Um interface to the called MS

for decoding. In the MS-MS call process, the coding and decoding are continually

performed twice. This is referred to as repeated coding and decoding.

Overview of TrFO

The TrFO feature enables the calling MS and called MS to use the same speech coding.

Therefore, the speech signal is coded at the calling MS once and decoded at the called

MS once. This solves the problem of speech signal damage in repeated coding and

decoding, improving the signal quality.

In the GSM network, the coding capability of each cell can be dynamically configured.

The coding scheme of the Um interface is determined by the BSS. When implementing

the TrFO, the MSC server selects the speech version supported by the cells where the

calling MS and called MS are located based on the coding capability of the cells. Then,

the MSC sets the expected speech version to a highest value. In this way, the TrFO can

be successfully implemented.

1) The BSC selects the speech version according to the Preferred Codec List carried in

the assignment request sent by the MSC.

2) To improve the success rate of TrFO, the BSC sends the Complete Layer 3

Information message carrying the coding schemes supported by the cells to the MSC.

3) To perform the TrFO services on the established calls, the MSC sends the INTERNAL

HANDOVER ENQUIRY message carrying the specified Speech Codec to the BSC to

trigger the intra-BSC handover.

Differences between TrFO and TFO

Both TrFO and TFO use the speech compression in the CN. Both features avoid the

repeated code conversions during the MS-MS call and improve the QoS. The two

features, however, are different from each other. TFO is enabled, disabled, and controlled

by the TRAU after a call is established. When the encoder and decoder use the same

coding/decoding scheme, the TFO is enabled to transmit the compressed speech. TrFO,

however, does not require the TRAU. It uses the OoBTC to negotiate the

coding/decoding type of both the calling MS and called MS before the call is established.

Then, the compressed speech is transmitted after the call is established.

If the requirement for TrFO is not met, it takes some time to configure the TRAU for

restoring the PCM coding/decoding. Without the TRAU, the call fails. In TFO, however,

the PCM coding is immediately used when the requirement for TFO is not met.

Therefore, the speech quality is not affected.

Enhancement

None

Dependency


None




11




This feature depends on the following features:




The CN must support this feature.

1.1.7 GBFD-115703 Automatic Noise Compensation (ANC)

Availability


Summary

Through the assessment of the background noise of the local end and the speech level of the

peer end, this feature adaptively increases the speech volume of the peer end if the

background noise of the local end is heavy. Therefore, the ratio of the peer end speech to the

background noise of the local end is increased and the speech quality is improved.

Benefits

Good speech quality is a basic requirement for a superior network. It is also the basic

requirement of the customer and helps in testing the product of the equipment manufacturers.

The problems such as acoustic echo, background noise, and packet loss must be solved to

ensure the speech quality. In addition, the gain of the signals should be controlled. Different

manufacturers have different algorithms and features to solve these problems.

Huawei GBSS uses the ANC feature to improve the speech quality in the scenarios with

heavy background noise such as in the downtown, marketplace, and cinema. Therefore, the

user satisfaction is increased and a network with enhanced performance is provided.

Description

The ANC compensates the noise through the algorithm. Through the assessment of the

background noise of the local end and the speech level of the peer end, this feature adaptively

increases the speech volume of the peer end if the background noise of the local end is heavy.

Therefore, the ratio of the peer end speech to the background noise of the local end is

increased so that the listener can clearly hear the speaker.

This feature is disabled by default. The ANC threshold is the ratio of the peer end speech to

the background noise of the local end, which can be manually configured. The maximum

adjustment range is the maximum gain of the ANC, which can also be manually configured.

For the speech handling, refer to the ITU-T G.169 specifications.

This feature is a feature of the TC devices and cannot be used together with the TrFO or TFO.




12

Enhancement

GBSS14.0

A counter is provided to measure the number of times SNRs occur at different levels.

Dependency


None







GBFD-115701 TFO

GBFD-115702 TrFO




None

1.1.8 GBFD-115704 Enhancement Packet Loss Concealment (EPLC)

Availability


Summary

This feature applies to the EFR, AMR FR, and AMR HR speech versions.

When the BSS receives the speech coding, the frames of the lost packets can be recovered and

compensated through the algorithm. Therefore, the anti-interference capabilities of the EFR,

AMR FR, and AMR HR speech versions and the speech quality are improved.

Benefits

With this feature, the frames of the lost packets can be recovered and compensated. This, to a

certain extent, solves the problem of speech frame loss during transmission and in a poor

radio environment. Therefore, the speech quality is improved, the user satisfaction is

improved, and a network with enhanced performance is provided.

In the case of packet loss of different severities, the MOS can be increased by 0 to 0.2.




13

Description

The problems such as acoustic echo, background noise, and packet loss must be solved to

ensure the speech quality. In addition, the gain of the signals should be controlled. Different

manufacturers have different algorithms and features to solve these problems.

This feature uses the patented algorithm to restore the lost frames during the transmission and

in a poor radio environment based on the information about the previous frame. This

implements the compensation for the frames of the lost packets.

This feature is a feature of the TC devices. It is used to process the AMR speech and

controlled by a switch. This feature cannot be used together with the TrFO or TFO because

the TC is not involved in the TrFO or TFO.

Enhancement

GBSS13.0

The packet loss prediction algorithm is optimized so that the received voice gets closer to the

original voice in fidelity, improving user experience.

Dependency


None





GBFD-115501 AMR FR or GBFD-115502 AMR HR




GBFD-115701 TFO

GBFD-115702 TrFO



It is recommended working with the following features:



None




14

1.1.9 GBFD-115711 EVAD

Availability


Summary

This feature helps telecom operators promote their value-added music services.

Benefits

This feature enhances the encoding effect of music (such as ring back tone (RBT) service and

voice information service) that uses the EFR, AMR FR, or AMR HR coding schemes and

therefore improves user experience.

Description

The earlier Voice Activity Detection (VAD) algorithm may consider soft music as silence and

mistakenly encode music in the downlink. This affects user experience.

The Huawei proprietary Enhanced VAD (EVAD) algorithm increase music recognition

accuracy. It greatly reduces the probability that music is mistakenly considered as silence,

improving user experience.

Enhancement

None

Dependency


None





GBFD-115501 AMR FR

GBFD-115502 AMR HR

GBFD-113301 EFR

GBFD-114801 Discontinuous Transmission (DTX)-Downlink

If EVAD is enabled for a call, the following features cannot be enabled at the same time:

GBFD-115701 TFO

GBFD-115702 TrFO





15


This feature cannot be used with any of the following features:




None

1.1.10 GBFD-116801 Voice Quality Index (VQI)

Availability


Summary

The voice quality index (VQI) feature provides a direct method of measuring the voice quality

of the radio network. By measuring the uplink VQI and downlink VQI, the voice quality of

the network is quantified, which provides a reference for future network optimization.

Benefits

The VQI can measure the voice quality of the network rapidly and effectively and therefore

provide a reference for network optimization.

Description

The VQI establishes the mapping between the radio network performance and voice quality.

The VQI value, which helps learn the voice quality, is calculated based on the parameters

related to the radio quality of the uplink/downlink speech signals. The MOS analysis method

is applied in VQI to measure the voice quality. The MOS is used to assess the quality of the

middle-rate and low-rate voice coding. The MOS value ranges from 1 to 5.

Based on the MOS analysis method, Huawei further divides the voice quality into 11 levels.

The VQI is obtained through the analysis of the BER, FER, LFE, and CODE of the

uplink/downlink speech signal. In this manner, the voice quality is quantified to facilitate the

identification of the voice problem and network optimization.

Enhancement

None

Dependency


None







16

Downlink VQI depends on the following feature:

GBFD-117501 Enhanced Measurement Report (EMR)



1.1.11 GBFD-115708 Um Interface Speech Frame Repairing

Availability


Summary

This feature automatically repairs the bit-error speech frames over the Um interface,

improving the voice quality. The feature is implemented by applying an enhanced decoding

technique to the Um interface.

Benefits

This feature helps improve the voice quality. The improvement is more significant when the

carrier-to-interference ratio (C/I) is low.

Description

When the bit error rate (BER) is high and the C/I is low, voice quality will deteriorate if

bit-error voice frames are discarded. To solve this problem, an enhanced decoding technique

is adopted to repair the erroneous speech frames over the Um interface. This technique

increases the success rate of voice decoding, improving the voice quality under low C/I. After

this feature is applied, the mean opinion score (MOS) can be increased by 0.1 to 0.2 under

low C/I.

Enhancement

None

Dependency




None


None


None




17

1.2 AMR Package

1.2.1 GBFD-115501 AMR FR

Availability


Summary

In a situation where interference is likely to occur, better voice quality can be provided if the

system uses AMR FR. In the same conditions, the voice quality in AMR FR is the same as or

better than the voice quality in EFR.

Benefits

This feature has the following benefits:

Increases the capacity of the system in physical areas.

Enhances the anti-interference capability to adapt to tight frequency reuse.

Improves the network indexes in an increasingly complex radio environment in

combination with the frequency hopping technology.

Provides a better voice quality for the subscriber.

Description

The AMR is an integration of multiple voice encoding/decoding rates. With different

encoding/decoding rates, the voice code streams of different rates are yielded. The AMR

enables the BTS and MS to select an appropriate encoding/decoding algorithm and to adjust

the encoding rate based on the specific radio environment. Therefore, the voice quality of the

entire wireless communication system is improved.

When there is a lot of interference on the radio channels, better voice quality can be provided

in AMR FR than in EFR or FR. In addition, the system in AMR FR has a higher

anti-interference capability to adapt to tight frequency reuse.

In the wireless communication system, the higher the original speech rate involved in channel

encoding, the more the information about the speech characteristics carried in the coded

stream and therefore the higher the fidelity of the speech. However, the redundant information

in the coded stream decreases, and therefore the coded stream becomes more interference

sensitive. In a poor wireless communication environment, bit errors occur easily and the

speech frames may be lost. Therefore, voices may be discontinuous. If the original speech rate

involved in channel encoding is reduced, more redundant information is carried in the coded

stream. Then the coded stream has strong anti-interference and error correction capabilities.

Therefore, the continuity of voice can be improved.

The AMR FR provides a selection of multiple coding rates from 4.75 kbit/s to 12.2 kbit/s, as

listed in the following table.

Channel Coding Rate

TCH/AFS 12.2 kbit/s

10.2 kbit/s




18

Channel Coding Rate

7.95 kbit/s

7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

Enhancement

GBSS8.1

The anti-interference capability of signaling transmission is enhanced in GBSS8.1.

If the original speech rate involved in channel encoding is reduced, the coded stream can

contain more redundant information. Then the coded stream has stronger anti-interference and

error correction capabilities and the voice continuity is improved as a result. The signaling

transmission performance, however, is not improved. After this feature is enabled, the

transmit power is increased during signaling transmission to increase the success rate of

signaling transmission. This can avoid voice interruption concerned with signaling

transmission in poor radio environment.

GBSS13.0


E-coder improves the AMR FR speech quality by using the enhanced spectrum technique and

LSP exact-calculate technique. In this way, E-coder increases the Mean Opinion Score (MOS)

by 0.05 to 0.12. In A over IP or TFO, E-coder is not supported.

Dependency


None





GBFD-115503 AMR Power Control


The MS and the CN must support this feature.




19

1.2.2 GBFD-115502 AMR HR

Availability


Summary


system uses AMR HR. In the same conditions, the voice quality in AMR HR is the same as or

better than that in HR. If the AMR HR feature is enabled, the half-rate speech feature must be

enabled at the same time.

Benefits


Increases the capacity of the system in physical areas.

Enhances the anti-interference capability to adapt to tight frequency reuse.

Improves the network indexes in an increasingly complex radio environment in

combination with the frequency hopping technology.

Provides a better voice quality for the subscriber.

Description


system uses AMR HR. In the same conditions, the voice quality in AMR HR is the same as or

better than that in HR. Therefore, if the communication quality meets the requirements, the

AMR HR can be widely used to increase the system capacity. When much interference exists

and the voice quality decreases, the system automatically switches to the AMR FR so that the

voice quality and the system capacity are balanced in real time. In this manner, the system can

provide good voice quality to subscribers when the system capacity is increased.

The AMR HR provides a selection of multiple coding rates, as listed in the following table.

Channel Coding Rate

TCH/AHS 7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

Enhancement

GBSS8.1

The TCH/AHS 7.95 kbit/s coding rate is supported in GBSS8.1.




20

The BTS using the Abis over IP or Abis transmission optimization function can provide the

speech services with the coding rate of AMR HR 7.95 kbit/s. The following table lists

multiple coding rates of the AMR HR.

Channel Coding Rate

TCH/AHS 7.95 kbit/s

7.40 kbit/s

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

Enhanced anti-interference capability of signaling transmission: If the original speech rate

involved in channel encoding is reduced, the coded stream can contain more redundant

information. Then the coded stream has stronger anti-interference and error correction

capabilities and the voice continuity is improved as a result. The signaling transmission

performance, however, is not improved. After this feature is enabled, the transmit power is

increased during signaling transmission to increase the success rate of signaling transmission.

This can avoid voice interruption due to signaling transmission in poor radio environment.

GBSS13.0


E-coder improves the AMR HR speech quality by using the enhanced spectrum technique and

LSP exact-calculate technique. In this way, E-coder increases the Mean Opinion Score (MOS)

by 0.05 to 0.12. In A over IP or TFO, E-coder is not supported.

Dependency


None




This feature depends on:

GBFD-113401 Half Rate Speech


GBFD-115503 AMR Power Control






21

1.2.3 GBFD-115503 AMR Power Control

Availability


Summary

Using different AMR power control algorithms, this feature can provide better

anti-interference capability, larger network capacity, and better voice quality.

Benefits


Reduces the transmit power and prolongs the standby time of the MS.

Reduces the network interference and improves the frequency usage.

Improves the network quality.

Description

The AMR speech coding scheme can select one of the coding rates according to the radio

channel quality to achieve an optimized combination of speech coding rate and channel

coding rate. In this manner, the AMR speech coding scheme can provide the best voice

quality in the current radio environment and meet the communication requirements in various

radio environments. The coded stream contains more redundant information. Then the coded

stream has stronger anti-interference and error correction capabilities and the voice continuity

is improved as a result. The system automatically decides whether to adopt the AMR. If the

system uses the AMR, the power control strategy for the AMR calling is different from that

for the non-AMR calling. In this manner, the network interference is reduced, the BTS

transmit power is saved, and the standby time of MS is prolonged.

Enhancement

None

Dependency


None





GBFD-115501 AMR FR

GBFD-115502 AMR HR





22

None

1.2.4 GBFD-115504 AMR FR/HR Dynamic Adjustment

Availability


Summary

Through the dynamic adjustment of AMR HR and AMR FR, the cell capacity and the voice

quality are balanced.

Benefits


Less maintenance work is required because the system can automatically adjust the ratio

of AMR FR to AMR HR based on the network capacity and quality.

This feature expands the network capacity and reduces the network deployment cost

without degrading the voice quality.

Description

Through the dynamic adjustment of AMR HR and AMR FR, this feature helps to balance the

cell capacity and the voice quality.

After completing the initial voice coding after setting up a call, the BSS calculates the radio

quality index (RQI) based on the uplink signal quality measured by the BTS. Then, based on

the uplink quality, the code sets activated by the BSC, and the corresponding thresholds, the

system determines the encoding/decoding scheme used for the uplink. In addition, the system

dynamically adjusts the voice coding rate in the uplink, and informs the MS to use the

selected voice coding rate. According to the RQI and parameters such as network capacity, the

BSS decides whether to enable the AMR FR/HR dynamic adjustment in the cell to balance the

voice quality and the cell capacity.

The AMR FR/HR dynamic adjustment in different radio environments and capacity

configurations helps to balance the voice quality and the cell capacity. Before enabling the

AMR FR/HR dynamic adjustment feature, you must enable the half rate speech and AMR HR

features.

Enhancement

None

Dependency


None







23

None


None

1.2.5 GBFD-115505 AMR Radio Link Timer

Availability


Summary

The radio link timer is used for the detection of the radio link quality. When the timer expires

due to poor radio link quality, the system deactivates the radio channel and interrupts the

conversation. In this manner, the timer can improve the channel utilization and prevent

channels with poor quality from occupying radio channel resources for a long time.

Benefits


Prolongs the duration of the AMR voice service with high anti-interference capability

and therefore reduces the call drop rate by setting the radio link timer of AMR voice

service and that of non-AMR voice service separately.

Improves the user experience and increases the operators' revenue by prolonging the

AMR call duration in the network of poor radio link quality.

Description

This feature provides a special radio link timer for AMR calls. AMR calls enjoy higher

robustness than common calls. Therefore, when a common call fails due to poor radio link

quality, the AMR voice service can maintain good conversation quality. If the radio link timer

of the AMR call and that of a common call are set to the same value, the chance of AMR call

drop increases and the user experience deteriorates. In this case, you should set the AMR

radio link timer to a larger value so that the AMR call endures the poor radio environment and

the call drop rate is reduced.

You can configure the radio link timers for the AMR HR and the AMR FR separately.

Enhancement

None

Dependency


None







24

None


None

1.2.6 GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment

Availability


Summary

Through the setting of the target voice quality and the real-time monitoring of the current

voice quality, the GBSS devices can adjust the coding rate adjustment threshold so that the

AMR speech can select an appropriate coding rate to enable the voice quality to approach the

target voice quality.

Benefits


Enables the AMR speech to select an appropriate coding rate.

Ensures the performance of the AMR speech.

Description

The AMR speech rate set consists of multiple coding rates. Based on the measured receive

level, receive quality, and carrier-to-interference ratio, and in combination with the algorithm,

the BTS and MS adjust the AMR call control parameters to select a speech source coding rate

that adapts to the existing radio environment. The appropriate selection helps achieve an

optimal combination of the channel quality and speech coding rate and improve the voice

quality to the greatest extent in the existing radio environment.

Generally, network planning engineers set the AMR speech coding rate adjustment threshold

to a fixed value after assessing the radio channel quality. If the radio channel quality changes

or the network planning engineers’ assessment of the radio channel quality is inaccurate, the

AMR speech will fail to select an appropriate coding rate. The AMR voice quality is then

affected.

Based on the setting of the target voice quality and the real-time monitoring of the current

voice quality, this feature adjusts the coding rate adjustment threshold so that an appropriate

coding rate can be selected to ensure the AMR voice quality.

The AMR coding rate adjustment threshold involves the adjustment threshold on the uplink

and the adjustment threshold on the downlink.

Uplink: After comparing the uplink quality indication with the coding rate adjustment

threshold, the BTS obtains an appropriate coding rate for the MS. Then, the BTS sends this

coding rate to the MS through the in-band signaling for adjusting the coding rate.

Downlink: After comparing the downlink quality indication with the coding rate adjustment

threshold, the MS obtains an appropriate coding rate for the BTS. Then, the MS sends this

coding rate to the BTS through the in-band signaling. The BTS comprehensively considers




25

the restrictions on the network side and then adjusts the downlink coding rate. Meanwhile, the

BTS notifies the MS of the selected downlink coding rate so that the MS uses the same coding

rate for decoding.

GBSS8.1 supports the AMR coding rate threshold adaptive adjustment on the uplink.

Enhancement

GBSS9.0

AMR coding rate threshold adaptive adjustment on the downlink: The AMR coding rate

threshold is used to control the selection of the AMR coding rate. When the threshold is fixed,

the AMR speech cannot select an appropriate coding rate if the radio channel quality changes

or the network planning engineers’ assessment of the radio channel quality is inaccurate. The

AMR voice quality is then affected.

This feature enhancement supports the adaptive adjustment of the AMR coding rate

adjustment threshold on the downlink based on the speech quality. The BTS obtains the frame

erase ratio (FER) of the current call based on the enhanced measurement report (EMR)

submitted by the MS and then estimates the speech quality (SQ). If the estimated speech

quality is distinct from the target speech quality, you can infer that the configured threshold is

inappropriate. Then, the GBSS adjusts the threshold based on certain algorithm. The BTS

sends the adjusted AMR coding rate threshold to the MS through the robust AMR traffic

synchronized control channel (RATSCCH). Subsequently, the MS adjusts the AMR coding

rate during the call on the basis of this coding rate adjustment threshold.

Dependency


None



Dependency on other functions of the GBSS

"AMR coding rate threshold adaptive adjustment on the downlink" depends on the following

feature:



GBFD-115701 TFO




None




26

1.2.7 GBFD-115507 WB AMR

Availability


Summary

Wide Band AMR (WB AMR) is a coding scheme, which significantly improves the speech

quality. WB AMR supports the rates of 6.60 kbit/s, 8.85 kbit/s, and 12.65 kbit/s.

Benefits Compared with the narrow band AMR, WB AMR achieves better speech quality.

Because the speech quality is improved, subscribers tend to spend more time on the call.

This increases the revenue of the operators.

The better speech quality of WB AMR than that of PSTN assists the wireless operators

in prompting subscribers of fixed networks to switch over to wireless networks.

Description

WB AMR is a coding scheme that can significantly improve speech quality. With WB AMR,

the sampling rate is increased to 16 kHz and the speech frequency range is extended to 0.05–7

kHz. WB AMR provides clear and loud voice and high-quality speech compared with the

narrow band AMR with the sampling rate of 8 kHz and the speech frequency range between

200 Hz and 3400 Hz.

WB AMR adopts the Guassian Minimum Shift Keying (GMSK) mode and supports the rates

of 6.60 kbit/s, 8.85 kbit/s, and 12.65 kbit/s on full-rate TCHs.

To achieve ideal speech quality, the end-to-end WB AMR call should be implemented. The

one-end WB AMR call requires two-time PCM coding scheme, which adversely affects the

speech quality. When the end-to-end WB AMR and the TFO are used together, a call needs

only one-time coding scheme, which helps to maintain high speech quality. If the end-to-end

WB AMR call cannot be established, the BSC will set up an AMR FR call instead of the

one-end WB AMR call because the speech quality and robustness of the one-end WB AMR

call are not necessarily better than those of the AMR FR call. Huawei BSS equipment

supports the WB AMR feature in Abis over TDM, Abis over IP, and Abis over HDLC

transmission modes.

Enhancement

None

Dependency


None







27

None


The MS, BTS, and MGW/MSC server must support this feature.

1.3 Voice Capacity

1.3.1 GBFD-113401 Half Rate Speech

Availability


Summary

With this feature, the speech coding rate is reduced to half the full-rate speech coding rate

through a new speech coding algorithm. In this manner, the physical channel carrying the

service of one MS is able to carry the services of two MSs.

Benefits

This feature enables the operator to expand the network capacity and improve the frequency

usage without increasing the hardware investment. In addition, a higher traffic volume can be

carried on an E1.

Description

With the increase of the GSM subscribers, the frequency resources of the existing GSM

network are insufficient. The half-rate service helps increase the number of speech channels

configured for one TRX. This increases the frequency usage without greatly reducing the

voice quality and expands the network capacity without increasing the hardware investment.

The half-rate service has the following benefits:

Saving the resource on the Um interface

The half-rate speech coding rate is reduced to half the full-rate speech coding rate

through the new coding algorithm. In addition, the multiframes on the Um interface are

used by two MSs with one MS receiving the even-numbered multiframes and the other

MS receiving the odd-numbered multiframes. In this manner, the physical channel that

supports one MS in the full-rate service can carry two MSs in the half-rate service. The

entire network interference is reduced because fewer timeslots are seized.

Saving the resource on the Abis interface

In half-rate service, one 16 kbit/s channel carries two calls on the Abis terrestrial circuit.

In this manner, a higher traffic volume is carried on the terrestrial link. The load on the

RSL, however, is heavy because one TRX carries a higher traffic volume. Therefore,

when configuring signaling multiplexing, use the 2:1 mode instead of the 4:1 mode.

Enhancement

GBSS7.0

The half-rate service can be used to save the resources on the Ater interface.




28

When the Flex Ater feature is enabled, the 8 kbit/s circuit is allocated to the half-rate call over

the Ater interface. In this manner, the transmission resources on the Ater interface are saved.

GBSS8.1

The half-rate channel is preferentially allocated when transmission resource congestion occurs

on the Abis interface.

The half-rate channel is allocated based on the resource congestion condition on the Abis

interface. The load on the Abis interface is calculated in real time. When the resources on the

Abis interface are congested, the BSC preferentially allocates a half-rate speech channel to a

call to relieve the resource congestion.

The dynamic conversion between half-rate and full-rate channels is triggered when resource

congestion occurs on the Um or Abis interface.

The dynamic conversion between half-rate and full-rate channels is triggered based on the

resource congestion condition on the Um or Abis interface. When the resources are congested,

the conversion from the full-rate call to the half-rate call can relieve the congestion.

Dependency


None





GBFD-117301 Flex Abis

GBFD-116901 Flex Ater


The MS and the MSC must support this feature.

1.3.2 GBFD-113402 Dynamic Adjustment Between FR and HR

Availability


Summary

With this feature, the full-rate (FR) channels and the half-rate (HR) channels are dynamically

converted to automatically adapt to the proportions of FR channels and HR channels in a cell

during the call. In this manner, the situation in which one type of channel is congested

whereas the other type of channel is idle can be prevented.




29

Benefits


Improves the channel usage because the channel is adjusted according to the requirement

of the call.

Reduces the workload of the network OM personnel because the full-rate channel and

the half-rate channel are automatically converted.

Description

If the half-rate channel is configured, the full-rate channel and the half-rate channel are

dynamically converted as required to automatically adapt to the proportions of FR channels

and HR channels in a cell during the call. In this manner, the situation in which one type of

channel is congested whereas the other type of channel is idle can be prevented. In addition,

the proportions of FR channels and HR channels in a cell can be controlled through related

parameters.

During the call, the channel is allocated based on the resources in the MS, MSC, and BSC. If

a half-rate channel is required but is unavailable, a full-rate channel is converted into two

half-rate channels. If a full-rate channel is required but is unavailable, the half-rate channels

are converted into full-rate channels.

Each time a call is released, the attributes of the channel are not changed and the converted

channel is not immediately switched back to its original form. If the load of the cell is normal,

the proportions of FR channels and HR channels in a cell are maintained at a certain value

through the automatic adjustment of the calls. The conversion between the half-rate channels

and the full-rate channels occurs when the load of the cell is high or when the congestion

occurs.

Enhancement

GBSS14.0

If a policy is used that preferentially allocates HR channels to an MS, the BSC determines

whether the receive level is higher than the preset threshold during a handover or a channel

assignment. If the receive level is higher than the threshold, the BSC allocates HR channels to

the MS. If the receive level is lower than the threshold, the BSC preferentially allocates FR

channels to the MS.

Dependency


None




This feature depends on the following feature:

GBFD-113401 Half Rate Speech





30

None

1.3.3 GBFD-115522 Dynamic HR/FR Adaptation

Availability


Summary

With this feature, the established calls can be handed over between half-rate channels and

full-rate channels based on the usage of channel resources. In this manner, the balance

between the network quality and the cell capacity is maintained.

Benefits


When the traffic volume is low, calls are handed over from half-rate channels to full-rate

channels, improving the voice quality.

When the TCHs in a cell are insufficient, calls are handed over from full-rate channels to

half-rate channels, increasing the cell capacity.

Description

During call establishment, the network assigns a half-rate or a full-rate channel to the call

based on the usage of the cell resources. In the case of a long-duration call, the usage of the

cell resources may change: During the call establishment phase, if the TCH seizure rate is

high, a half-rate channel is assigned to the call. After the call lasts for a period, many calls are

released and the TCH seizure rate decreases. In this case, TCHs in the cell are sufficient and a

full-rate channel can be assigned to the call to improve the voice quality. If the TCH seizure

rate is low during the call establishment, a full-rate TCH may be assigned to the call. After the

call lasts for a period, many calls access the cell and the TCH seizure rate increases. In this

case, the available TCHs in the cell are insufficient.

If the dynamic adjustment between full-rate and half-rate channels is enabled, the

half-rate/full-rate channels of established calls can be adjusted based on the usage of cell

resources. When the TCHs in a cell are sufficient, full-rate channels are preferably assigned to

new calls and calls with poor communication quality can be handed over from half-rate

channels to full-rate channels, improving the communication quality. When the TCHs in a cell

are insufficient, half-rate channels are preferably assigned to new calls and calls with good

communication quality may be handed over from full-rate channels to half-rate channels,

increasing the cell capacity.

When this feature is enabled, the half-rate speech feature needs to be enabled at the same

time.

Enhancement

None

Dependency





31

None




None


None

1.3.4 GBFD-115830 VAMOS

Availability


Summary

Voice services over Adaptive Multi-user Orthogonal Subchannels (VAMOS) is a feature based

on which two users are multiplexed onto one HR channel to increase network capacity.

VAMOS helps increase the network capacity.

Benefits

In a network where refarming is applied and speech channels are insufficient, the GSM

network capacity can be increased through software without changing the existing GSM

network architecture. The network capacity increase by VAMOS is 20% in the scenarios that

100% SAIC MS penetration rate and 4x3 frequency reuse pattern.

Description

VAMOS is a technology to increase GSM network capacity. The network capacity is

increased by using HR channels and can be increased further by VAMOS based on the FR

channels. Tests tell that the VAMOS performance depends on the penetration rate of the MS

and the frequency reuse pattern.

VAMOS reduces network quality while increasing network capacity. The reduced network

quality should be tolerable for operators because the quality standards for a GSM network

with VAMOS are lower than those for a legacy GSM network. The following table lists the

VAMOS gains.

Frequency Reuse

Pattern SAIC MS Ratio (%) VAMOS Gain (%)

4x3

50% 10%-15%

75% 15%-22%

100% 20%-30%

3x3 50% 7%-12%

75% 10%-18%




32

100% 15%-25%

1x3

50% 5%-10%

75% 7%-15%

100% 10%-20%

The preceding table tells that the network capacity is not increased when the frequency reuse

is tight. Therefore, VAMOS can be enabled only when the frequency reuse is loose.

Enhancement

GBSS14.0

1. The radio resource management (RRM) algorithm is optimized for networks deployed

with VAMOS. The optimization reduces the negative impact of VAMOS on the call

drop rate and handover success rate. In addition, the channel preemption and timeslot

combination policies are modified to reduce the negative impact of VAMOS on ongoing

services.

2. Huawei BSCs work with the Huawei M2000 to enhance the performance of the features

VAMOS Mute SAIC MS Identification (feature ID: GBFD-115831) and VAMOS Call

Drop Solution (feature ID: GBFD-115832). This enables the BSCs to share information

about SAIC MS capabilities, reducing the negative impact of the two features on KPIs.

In addition, BSC reliability is improved because manual intervention is minimized.

Dependency


None




It depends on the following features:

GBFD-117601 HUAWEI III Power Control Algorithm

GBFD-115502 AMR HR or GBFD-113401 Half Rate Speech

GBFD-118103 Network Support SAIC

GBFD-117301 Flex Abis (in TDM transmission mode)

GBFD-118601 Abis over IP or GBFD-118611 Abis IP over E1/T1 (in IP transmission mode)

This feature is recommended working with the following features:

GBFD-113501 A5/1 and A5/2 Ciphering Algorithm

GBFD-113503 A5/3 Ciphering Algorithm

GBFD-114801 Discontinuous Transmission (DTX)-Downlink




33

GBFD-114803 Discontinuous Transmission (DTX)-Uplink



GBFD-117001 Flex MAIO

GBFD-510104 Multi-site Cell

GBFD-113521 A5/1 Encryption Flow Optimization

GBFD-510101 Automatic Frequency Correction (AFC)

GBFD-114001 Extended Cell


MS

1.3.5 GBFD-115831 Mute SAIC MS Identification

Availability


Summary

Mute SAIC MS Identification is a function based on which the SAIC-capable MSs that do not

report their SAIC capability to the BSS are identified so that the MSs can use VAMOS.

Benefits

This feature helps identify the MS capability correctly so that the SAIC-capable MSs can use

VAMOS. This increases the number of MSs that use VAMOS, increasing the network

capacity.

Description

Some mute SAIC MSs support SAIC but do not report the SAIC capability to the BSS. As a

result, the number of MSs that can be multiplexed by VAMOS is smaller than what it actually

is, and therefore the network capacity is limited.

This feature helps distinguish SAIC-capable MSs from SAIC-incapable MSs so that the

SAIC-capable MSs can use VAMOS.

Enhancement

None

Dependency


None





34


This feature is used together with the following features:

GBFD-115830 VAMOS





GBFD-115701 TFO





1.3.6 GBFD-115832 VAMOS Call Drop Solution

Availability


Summary

VAMOS Call Drop Solution is a function based on which call drops do not occur when the

MS is paired with VAMOS so that the system capacity and voice quality are not affected.

Benefits

With this feature, call drops no longer occur when the SAIC-capable MS use VAMOS. In this

manner, the network capacity is increased and services remain normal.

Description

Mainstream multi-mode MSs report the SAIC capability to the BSS. Call drops, however,

frequently occur when the MSs use VAMOS. Tests tell that this is caused by defective

automatic frequency control (AFC) of the MSs in the case of VAMOS multiplexing. This

feature prevents call drops of SAIC-capable MSs.

This feature involves the following processes:

1. The BSS distinguishes the normal SAIC-capable MSs (that experience call drops) from the

defective ones (that do not experience call drops).

2. Processing is performed on the defective ones that do not experience call drops in the case

of VAMOS multiplexing.

Enhancement

None




35

Dependency


None



This feature is used together with the following features:

GBFD-115830 VAMOS





GBFD-115701 TFO





1.4 Cell Broadcast

1.4.1 GBFD-113601 Short Message Service Cell Broadcast (TS23)

Availability


Summary

The short message service cell broadcast (SMSCB) is a teleservice (TS23) through which all

the MSs in the specified area can periodically receive messages.

Benefits

The SMSCB can increase the revenue of the operator by providing weather forecast, stock

information, and sales promotion information based on the location of the MS.

Description

The SMSCB is a teleservice that periodically broadcasts messages to all the MSs in a

specified area. Based on different settings, the MS can continuously or discontinuously

receive short messages, such as weather forecast and traffic information.




36

The SMSCB allows all the MSs in a specified area to receive short messages. The area may

cover one or more cells, or the entire PLMN. The short messages from the cell broadcast

center (CBC) are managed and scheduled in the CDB of the BSC, which sends the short

messages to the BTS. The BTS then broadcasts the messages to all the MSs in a specified area

at certain intervals.

The CDB receives and stores the short messages, schedules and sends the messages according

to a certain algorithm, and responds to the query from the CBC.

The MS can receive the messages in DRX mode. That is, the MS can work discontinuously.

Through a scheduling message, the BSC notifies the MS that no short message is sent during

a period. Therefore, the MS needs to receive the short messages only in the specified period

and does not need to detect the messages continuously. Therefore, the power consumption is

reduced.

The SMSCB supports the BTS flow control. That is, the order in which the short messages are

sent is scheduled by the CDB, but the sending of the messages is implemented by the BTS.

Each TRX of the BTS maintains one message buffer and periodically sends the cell broadcast

short message on a specified channel. When the messages are not sent in time, the BTS

reports the out-of-synchronization situation to the BSC through a LOAD IND message. By

controlling the BTS flow, the CDB maintains the balance of the cell broadcast system and

therefore meets the requirements of the message sending.

Enhancement

None

Dependency


None




This feature and the following feature are mutually exclusive:

GBFD-113602 Simplified Cell Broadcast


The CBC should be used.

1.4.2 GBFD-113602 Simplified Cell Broadcast

Availability


Summary

This feature is implemented by using a built-in cell broadcast processing module in the BSC

in the case that a CBC is not used.




37

Benefits

Without a CBC, Huawei simplified cell broadcast feature supports the most commonly used

standard cell broadcast services with low equipment costs and low OM costs, reducing the

operator's CAPEX.

Description

With the SMSCB function, short messages are broadcast to all MSs in one or several cells, or

even in the entire PLMN. The MSs can receive the broadcast messages continuously or

discontinuously.

Generally, a CBC is responsible for managing and scheduling the SMSCB.

Huawei simplified cell broadcast feature is performed through a built-in cell broadcast

processing module in the BSC, reducing the equipment costs.

Huawei simplified cell broadcast feature is performed to broadcast messages such as the cell

name, weather forecast, and social welfare messages. These functions are described as

follows:

Information broadcast function

Messages are broadcast, such as the BTS name, cell name, weather forecast, and any

character string with a maximum of 80 characters.

Information timing broadcast function

Cell broadcast messages are sent at specified intervals during a specified period of time.

Information management function

The MML commands are used to start or stop sending the broadcast messages in

specified cells or all cells, or stop sending a specified cell broadcast message. In addition,

the cell broadcast status can be viewed by running the MML commands.

In any period of time, a maximum of 16 cell broadcast short messages can be sent

simultaneously in one cell.

Enhancement

GBSS8.1

A maximum of 64 cell broadcast short messages can be sent simultaneously in one cell.

Dependency


None





GBFD-113601 Short Message Service Cell Broadcast (TS23)





38

None

1.5 GSM Trunking

1.5.1 GBFD-510301 Public Voice Group Call Service

Availability


Summary

The public voice group call service (VGCS) adopts the half-duplex mode and provides voice

services for a group of predefined MSs in a predefined area.

Benefits

With this feature, operators can provide a new half-duplex voice service for a group of

subscribers to meet the requirement of dispatching service. This service focuses on enterprise

users and government users. This service is called GSM Digital Trunking or Public Access

Mobile Radio (PAMR). Compared with multiparty communication service, VGCS can greatly

reduce the occupancy of radio channels and improve the utilization of radio channel

resources.

Description

VGCS simultaneously provides voice services for a group of MSs in a predefined area in

half-duplex mode.

The network side defines the group call number, group members and coverage area. The MS

who has the permission can dial the group call number to initiate a group call. All the group

members within the coverage area can be informed to join the group call. One of the group

members can press and hold PTT on the mobile phone to speak to others. During this period,

other members can only listen but cannot talk by pressing PTT. Other group members can

speak by pressing PTT only after the talker releases PTT. After the conversation is complete,

the originator terminates the VGCS call by pressing the on-hook key and then all the group

members hang up.

In addition, the VGCS provides dispatcher service. The dispatcher is a special subscriber of

the fixed network or the mobile network defined by the network side. The dispatcher has the

permission to talk at any time during a VGCS call and originates or terminates a VGCS call

authorized by the network side.

Enhancement

None

Dependency


None




39





GBFD-118601 Abis IP(Not exclusive in GBSS13.0 and later version)



The MSC, HLR, and MSs must support this feature.

1.5.2 GBFD-510303 Late Group Channel Assignment

Availability


Summary

After a VGCS call is established, if no group member involved in the call is in the cell within

the predefined coverage area, the VGCS traffic channel is not assigned. If a group member

accesses the cell during the VGCS call, then the network side assigns a traffic channel for the

call.

Benefits

This feature effectively saves the radio channel resources when operators promote

VGCS-based services.

Description

During VGCS, the voice of the talker is sent to other group members through the VGCS

channel of the cell. If no group member involved in the call is in the cell within the coverage

area, the VGCS channel is actually idle.

With this feature, the network side sends a VGCS call notice periodically in each cell within

the coverage area and the cell in which group members exist receives the response of the MS.

Then, the network side assigns a VGCS channel for the cell and notifies the group members to

join the VGCS call. The cells that do not respond are not assigned VGCS channels.

In addition, the network side periodically detects the MSs of all the cells within the coverage

area. If no group member involved in the VGCS call exists in a cell due to some reason, for

example, outgoing cell handover, the network side releases the VGCS channel assigned to the

cell.

Dependency


None





40








1.5.3 GBFD-510305 Single Channel Group Call Originating

Availability


Summary

When a VGCS/VBS call is originated, only one TCH is occupied.

Benefits

When a VGCS/VBS call is originated, the originating cell needs only one TCH. This

improves the utilization of frequency resources, reducing the congestion rate of TCHs during

busy hours, and enhancing the QoS of network.

Description

When a VGCS/VBS call is originated, the originating cell requires two TCHs by default,

where one TCH is a VGCS/VBS channel and the other TCH is used for the originator to talk

before a VGCS/VBS call is established. After the VGCS/VBS call is established, the network

switches the originator to the VGCS/VBS channel and then releases the TCH that is assigned

initially. This is called dual-channel group call originating.

In the single channel group call originating mode, the BSS switches the VGCS/VBS

originator from the SDCCH to the VGCS/VBS channel directly. In the entire VGCS/VBS

originating phase, no more traffic channels are occupied.

Enhancement

None

Dependency


None







41






1.5.4 GBFD-510306 Talker Identification

Availability


Summary

During a VGCS/VBS call, the real-time information of the current talker is displayed on each

MS of the subscriber involved in the call.

Benefits

Talker identification is a supplementary function of GSM Digital Trunking services, which

enables the MSs involved in a VGCS call to display the information regarding the talker such

as telephone number, subscriber name, and priority within the group. In this way, the group

members can obtain the real-time information of the current talker and determine whether to

initiate PTT preemption within the group.

Description

Like the function of Calling Name Identification Presentation (CNIP), talker identification

allows the information of the current talker to be displayed in real time on the MSs in the

VGCS/VBS. The information includes telephone number (subscriber name in the phonebook)

and priority.

During a VGCS/VBS call, the network side periodically broadcasts the talk information

including the MSISDN of the talker and the priorities of group members in the cell within the

coverage area. After receiving the information, the MSs of other subscribers display the

information of the current talker, including the MSISDN (or subscriber name in the

phonebook) and priority in the group. After the talker terminates the conversation, the

network side broadcasts the information periodically without the content of the talker and then

other group members remove the information displayed on the MSs.

Enhancement

None

Dependency


None





42







This feature complies with Huawei proprietary protocol and should be supported by the

MSC/VLR, HLR, and MS.

1.5.5 GBFD-510307 Group Call EMLPP

Availability


Summary

Group call eMLPP ensures timely services for the VGCS/VBS/point-to-point call subscribers

with high eMLPP priority by means of service/resource preemption.

Benefits

This feature allows operators to provide the VGCS on different levels, improving the user

satisfaction.

This feature enables operators to quickly respond to requirements during emergencies,

thereby guaranteeing the communications services, and fulfilling their social responsibility.

Description

The eMLPP feature allows the network to use different policies such as queuing, preemption,

and directed retry according to the calls with different priorities when the network resources

are seized. Group call eMLPP are categorized into seven priorities: A, B, and 0-4.

A: highest, for network internal use

B: for network internal use

0: for subscription

1: for subscription

2: for subscription

3: for subscription

4: lowest, for subscription

A and B are the highest priorities, which are used for the network maintenance. When

defining subscribers, operators must define the eMLPP priorities of the subscribers and the

VGCS group respectively.

Group call eMLPP consists of service preemption and resource preemption.

Service preemption




43

During a VGCS call or point-to-point call, the MS determines whether to accept the new

call (including a paging to the MS or a VGCS/VBS call) based on the priorities of these

two calls. If the MS supports service preemption, the MS determines whether to join a

call with high priority.

Resource preemption

If network resources (such as processing capability, signaling channels, and traffic

channels) are insufficient, calls with high priorities do not release network resources. In

this case, new calls with high priorities can queue or even preempt the resources seized

by the calls with low priorities. For details, see the description of GBFD-115001

Enhanced Multi Level Precedence and Preemption (EMLPP).

Enhancement

None

Dependency


None









1.5.6 GBFD-510308 Fast Group Call Setup

Availability


Summary

Fast group call setup can shorten the time of VGCS/VBS establishment by optimizing the

signaling process for establishing VGCS/VBS calls and the related data configurations.

Benefits

Fast group call setup ensures the VGCS/VBS scheduling efficiency on some special occasions

and meets the requirements of the VGCS/VBS subscribers.




44

Description

On some special occasions, the time of VGCS/VBS establishment needs to be shortened to

ensure the VGCS/VBS scheduling efficiency. To shorten the time of setting up group calls,

the signaling process for establishing VGCS/VBS calls and the related data configurations are

optimized.

Immediate assignment optimization: If the fast group call setup mode is adopted, the SABM

frame contains the IMMEDIATE SETUP message when an MS originates a VGCS call.

Therefore, the subsequent SETUP process can be omitted and the time of setting up VGCS

calls is shortened. The BSS optimizes the channel assignment procedure by using the

"Immediate TCH Assignment" and "Immediate Assignment Optimization" signaling

procedures. In addition, the signaling interworking process between the BSC and the BTS is

simplified, before the BSS sends the immediate assignment command to the MS. At the same

time, the bandwidth of the TCH is far greater than that of the SDCCH. Hence, the MS sets up

a link on the TCH quickly and easily.

NCH block number optimization: Configuring a large number of blocks occupied by the NCH

in a cell ensures that messages are quickly sent over the Um interface and speeds up the

VGCS call establishment.

Other procedure optimization: Omitting some procedures such as authentication, ciphering, or

TMSI reassignment can speed up the group call establishment.

Enhancement

None

Dependency


None




None



1.5.7 GBFD-510309 Group Call Reliability Enhancing

Availability


Summary

When the BTS is disconnected from the network, the BTS still supports the VGCS/VBS calls

for specified fixed group numbers within the coverage area.




45

Benefits

Based on this feature, when the BTS is disconnected from the network due to accident or

disaster, operators can still provide VGCS/VBS service in the area covered by the BTS,

enhancing user experience and brand image of the product.

Description

In addition to the system-specific reliability mechanisms such as active/standby switchover

and resource pool, Huawei GBSS VGCS/VBS also provides fail soft capability for the

VGCS/VBS feature to improve its reliability.

After the BTS is disconnected from the network, the BTS works in fail soft mode and

supports the VGCS/VBS within the coverage area. A single cell or several cells can be

configured under a BTS. The BTS automatically switches to normal working mode after the

transmission recovers

In fail soft mode, Huawei GBSS supports the regular call initiation. The BTS initiates a

VGCS call that is fixedly configured once the transmission is interrupted. Then, the

subscribers can seize the uplink to talk to the subscribers in other groups within the coverage

area of the BTS. The VGCS call, however, cannot be stopped so that the calls with high

priority can be set up automatically once the transmission is interrupted.

Enhancement

None

Dependency


None








None




46

1.5.8 GBFD-510302 Public Voice Broadcast Service

Availability


Summary

Public voice broadcast service (VBS) adopts the simplex mode and provides

point-to-multipoint voice services for a group of predefined MSs in a predefined area.

Benefits

This feature enables operators to provide a new broadcast-based voice service for the

subscribers and therefore increases the revenue.

Description

VBS is a special type of VGCS. After the network side determines the VBS call number,

group members, and coverage area, the MS who has the authority can dial the call number to

initiate a VBS call. All the group members within the coverage area can be informed to join

the VBS call. Only the originator can talk during a VBS call. The originator can talk without

pressing PTT during the call and other members can hear the voice of the originator. After the

conversation is complete, the originator terminates the VBS call by pressing the on-hook key

and then all the group members hang up.

In addition, the VBS provides dispatcher service. The dispatcher is a special subscriber of the

fixed network or the mobile network defined by the network side. The dispatcher can

originate and terminate a VBS call authorized by the network side. If the dispatcher is not the

originator of the VBS call, no one can talk during the call.

Enhancement

None

Dependency


None












47

1.5.9 GBFD-510304 Late Broadcast Channel Assignment

Availability


Summary

After a VBS call is established, if no group member involved in the call is in the cell within

the predefined coverage area, the VBS traffic channel is not assigned. If a group member

accesses the cell during the VBS call, then the network side assigns a VBS traffic channel for

the call.

Benefits

This feature effectively saves the radio channel resources when operators promote VBS-based

services.

Description

During a VBS call, the voice of the originator is sent to other group members through the

VBS channel of the cell. If no group member involved in the call is in the cell within the

coverage area, the VBS channel is actually idle.

With this feature, the network side sends a VBS call notice periodically in each cell within the

coverage area and the cell in which group members exist receives the response of the MS.

Then, the network side assigns a VBS channel for the cell and notifies the group members to

join the VBS call. VBS Channel is not assigned to the cells that do not respond.

In addition, the network side periodically detects the MSs of all the cells within the coverage

area during a VBS call. If no group member involved in the VBS call exists in a cell due to

some reason, for example, outgoing cell handover, the network side releases the VGCS

channel assigned to the cell.

Dependency


None












48

1.5.10 GBFD-510310 GSM-T Relay

Availability


Summary

The BSC forwards trunk calls to the trunk server through the call differentiation mechanism,

so that the equipment on the radio access side supports trunk services.

Benefits

Telecom operators can use the existing radio networks to provide trunk services. In other

words, trunk calls are processed as a type of service to eliminate the need for an independent

network. In this way, the radio network investment is decreased and the radio channel

utilization is increased.

Description

This feature is a solution for quickly achieving the trunk function by using the existing GSM

network. The following figure shows the network topology.

When a user initiates a call, the BSC determines whether the service type is trunk call or

public network point-to-point call based on the signaling. If the service type is trunk call, the

BSC forwards it to the trunk server. If the service type is public network point-to-point call,

the BSC forwards it to the MSC on the existing network so that the inheritance of public

network services is ensured. The trunk server does not affect public network services because

it is independent of the MSC on the existing network.

This feature is applicable to the inventory markets of Huawei wireless domain. Only the

addition of one core network and the upgrade of BSC software are required, with the advantage of fast network construction and low costs.




49

Enhancement

None

Dependency


None


None






The MS, MSC, and HLR must support this feature.

1.6 LCS

1.6.1 GBFD-115401 NSS-based LCS (Cell ID + TA)

Availability


Summary

The built-in serving mobile location center (SMLC) supports the NSS-based Cell ID+TA

location service.

Benefits

The location service (LCS) enables the network to provide various services for an MS based

on the location of the MS. These services include weather forecasts, trip scheduling,

emergency assistance, stock information, business planning, and transport conditions. In this

way, the revenue of operators increases.

Description

LCS is a series of services that is achieved based on locating the position of users in a certain

range, such as locating an emergency call or position information of users for value-added

services. LCS should reach the specified QoS, such as the required accuracy and latency.

Huawei supports NSS-based Cell ID+TA location scheme of the SMLC. The location

precision of this scheme is about 500 meters.




50

Enhancement

None

Dependency


None




None



1.6.2 GBFD-115402 BSS-based LCS (Cell ID + TA)

Availability


Summary

The built-in SMLC supports the BSS-based Cell ID+TA location service.

Benefits

This feature can provide location services and increase the revenue of operators.

Description

Huawei BSS provides the BSS-based CELL+TA mobile location service. The Cell ID + TA

location is used to estimate the distance between MS and BTS according to current parameter

TA, improving the location precision on the basis of Cell ID.

Huawei BSC integrates the SMLC. The interface between BSC and SMLC is an internal

interface. The location precision of this scheme is about 500 meters.

Enhancement

None

Dependency


None






51


None



1.6.3 GBFD-115403 Simple Mode LCS (Cell ID + TA)

Availability


Summary

The location information of the MSs can be directly displayed on the BSC LMT.

Benefits

With this feature, operators can provide location services and increase the revenue.

In addition, LCS helps in disaster relief, routine network optimization, and helps handle

emergency situations and customer queries

Description

Huawei BSS supports the simple mode LCS on the basis of the NSS-based LCS and

BSS-based LCS. The BSC transmits the location results to the BSC LMT by analyzing the

location information. In addition to the location information of the traced MS, the CGI, TA,

longitude and latitude of the cell, azimuth, and error can be provided.

Enhancement

None

Dependency


None




None


None




52

1.6.4 GBFD-115404 Lb Interface

Availability


Summary

Huawei BSS supports the standard Lb interface and the interconnection between Huawei BSC

and the stand-alone Serving Mobile Location Center (SMLC) to provide the location services

(LCS) for the MS. The location services can be based on the CELL ID+TA mode or the AGPS

mode.

Benefits Huawei BSS interconnects with the stand-alone SMLC to provide LCSs for the MS.

LCSs can increase the operator` s revenue. The operator can provide various LCSs for an

MS based on the location of the MS. These LCSs include weather forecasts, trip

scheduling, emergency assistance, stock information, business planning, and

transportation information.

Description

The Lb interface is a standard interface between the BSC and the SMLC. The SMLC

performs functions such as selecting the location mode and calculating the position of the MS

based on the measurement results provided by the MS or BSC.

Huawei BSS supports the standard Lb interface, and therefore can be interconnected with the

SMLC of other vendors to provide LCSs in CELL ID+TA mode or AGPS mode. The Lb

interface complies with 3GPP TS 48.071, 3GPP TS 49.031, 3GPP TS 44.031, and 3GPP TS

03.71.

Figure 1-1 shows the position of the SMLC in a network.

Figure 1-1 Position of the SMLC in a network

BTS

BTS

BSCMSC/

VLR

SMLC

GMLC

HLRHLR

LCS

client

Lb

Huawei BSS supports message tracing on the Lb interface and provides the traffic statistical

counters related to the LCSs. Huawei BSS supports flow control on the LCSs. When the

stand-alone SMLC is overloaded or when the number of location requests received by the

BSC exceeds the predefined threshold, the BSC rejects certain location requests to ensure the

normal operation of the location system.




53

Generally, Huawei BSC is interconnects with only one SMLC. When the RAN Sharing

feature is enabled, Huawei BSC can be interconnected with four SMLCs of four different

vendors.

Enhancement

GBSS14.0

The Lb Interface feature supports LCSs in U-TDOA mode only for tests.

The Huawei GBSS is used with a Type B location measurement unit (LMU) to provide

high-precision Lb-based LCSs in U-TDOA mode. LCSs in U-TDOA mode are only supported

by a Type B LMU.

LCSs in U-TDOA mode are applied in the following scenarios:

1. Abis TDM+Lb TDM

In this scenario, this feature must be used together with the feature GBFD-114701

Semi-Permanent Connection.

2. Abis IP+Lb IP

The SMLC, not the BSC, manages and directly communicates with the LMU. The BSC

performs only transparent transmission. The LMU and SMLC must be provided by the same

vendor.

Dependency





54

None


None



GBFD-115401 NSS-Based LCS (Cell ID + TA) or

GBFD-115402 BSS-Based LCS (Cell ID + TA) or

GBFD-115403 Simple Mode LCS (Cell ID + TA)


The MS must support the AGPS LCSs. The CN must support the LCSs.

LCSs in U-TDOA mode are only supported by a Type B LMU.

1.7 VIP Service

1.7.1 GBFD-116001 Resource Reservation

Availability


Summary

Resource reservation can reserve a certain number of TCHFs for the high-priority users.

Benefits

With this feature, the channel resources can be reserved for the high-priority users, which

guarantees the QoS for the VIP users and improve user experience.

Resource reservation provides a segmentation function for operators. With this feature,

operators can provide different levels of services for users with different priorities to increase

the revenue.

Description

With priority-based resource reservation, the system reserves a certain number of TCHFs for

high-priority users to ensure the QoS.

The reservation of the channel resources in a congested cell prevents the high-priority users

from eMLPP preemption and queuing. Therefore, the access rate of high-priority users speeds

up and success rate increases.

In addition, the half-rate service uses a coding mode different from that of the full-rate service

and has a coding rate of 5.6 kbit/s. Therefore, after the half-rate service is enabled, the voice

quality of the half-rate service deteriorates. The MSs of some low-priority users do not support the half-rate feature. Consequently, in the cells where the half-rate feature is enabled,




55

these MSs only occupy the TCHFs and have a high voice quality. However, the MSs of some

high-priority users which support the half-rate function. After the half-rate function is enabled

in a cell, the TCHHs are preferably assigned to the MSs. Therefore, the high-priority users

receive a low voice quality. The resource reservation feature reserves TCHFs for these

high-priority users to ensure the QoS.

The TCHFs can be reserved for the high-priority users as required. In each channel

assignment, if the users with the priority equal to or higher than the defined high priority and

the reserved channels is sufficient, the TCHFs are directly assigned to the users; if all the

reserved channels are assigned, the preemption flow is performed according to the eMLPP

rule.

If the priority of the user is lower than the defined high priority, the system checks whether

the total number of occupied channels and idle channels is greater than the number of

reserved channels. If the total number of occupied channels and idle channels is greater than

the number of reserved channels, the system initiates the normal call flow; otherwise, the

queuing and preemption flow are performed according to the queuing and eMLPP rule.

Enhancement

None

Dependency


None




This feature can be used together with GBFD-5001 Enhanced Multi Level Precedence and

Preemption (EMLPP), which can effectively improve user benefits and satisfaction.


None

1.7.2 GBFD-115001 Enhanced Multi Level Precedence and Preemption (EMLPP)

Availability


Summary

The enhanced multi-level precedence and preemption service (eMLPP) is a supplementary

service that is used to ensure a normal conversation of the subscriber with higher priority by

preemption, queuing, directed retry, and forced handover.




56

Benefits

This feature ensures the QoS of the VIP subscribers and improves their experience.

This feature allows operators to classify subscribers into different categories. Therefore,

operators can provide different levels of services for users with different priorities to increase

revenue.

Description

The eMLPP is a supplementary service offered by the GSM system. The eMLPP service

allows a subscriber to initiate calls with different priorities. The network side employs

different channel assignment strategies for the subscribers according to the priorities. If the

network is congested, the call with higher priority is served preferably.

The eMLPP service requires the support from MS to ensure that the subscriber can initiate

calls of different priorities under different situations. A normal conversation of the subscribers

with higher priority is ensured by preemption, queuing, directed retry, and forced handover.

With this service, the high-priority subscribers have an advantage in call establishment rate

and completion rate compared with the lower-priority subscribers according to different

priority configurations in a network.

The eMLPP service provides the following two mechanisms:

Preemption

The MSC determines whether preemption is allowed. Then, the MSC sends an

assignment request or handover request message to the BSC to notify the BSC whether

preemption is allowed. If the MSC allows for performing the preemption and eMLPP is

enabled, the BSC forcibly switches the call with lowest priority to a neighboring cell

when the TCHs are congested to release the resource for the call with high priority.

However, if eMLPP is not enabled, the BSC releases the resource of a low-priority user

directly to ensure that the call with high priority is served normally.

Queuing

The MSC determines whether queuing is allowed. Then, the MSC sends an assignment

request or handover request message to the BSC to notify the BSC whether queuing is

allowed. When the cell has no idle TCH and the MSC allows queuing, the BSC puts the

TCH request into the queue. Then, when idle TCHs are available, the TCH is assigned to

the waiting call in the queue. If the directed retry is allowed, the BSC performs directed

retry before the queue timer expires.

Enhancement

GBSS12.0:

eMLPP Enhancement:

The preemption and queuing functions are enhanced, and therefore the utilization of radio

resources is optimized.

When an outgoing BSC better cell handover occurs on a high-priority MS, the BSC notifies

the MSC and the target BSC that they should neither preempt the radio resources that are

allocated to other MSs for the high-priority MS nor queue the high-priority MS. On receiving

the incoming BSC handover request from a high-priority MS, the target BSC checks the type

of the handover. If the handover is a better cell handover, the target BSC neither preempts the

radio resources that are allocated to other MSs for the high-priority MS nor queues the

high-priority MS. In this way, the high-priority MS will never preempt the radio resources




57

that are allocated to a low-priority MS when the serving cell can provide service for the

high-priority MS.

When an intra-BSC handover (any handover other than better cell handover) occurs on a

high-priority MS, the BSC can preempt the radio resources that are allocated to a low-priority

MS for the high-priority MS. The high-priority MS is queued if the radio resources that are

allocated to a low-priority MS cannot be preempted. In this manner, the BSC ensures the

speech quality of the high-priority MS by preempting the radio resources that are allocated to

a low-priority MS when the serving cell cannot provide good service for the high-priority MS.

Dependency


None




None


The CN and HLR must support this feature.

1.7.3 GBFD-115002 Flow Control Based on Cell Priority

Availability


Summary

With this feature, when service congestion occurs in the GBSC, the flow control is started.

The calls in the VIP cells are preferentially processed. Therefore, the normal operation of the

GBSC and the call setup success rate of the VIP users are ensured.

Benefits

The operators can apply this feature in areas with a lot of VIP users, such as central business

districts (CBDs), saloon bars, and airports. In this way, the calls made by the VIP users are not

affected even if the BSC system is overloaded because of burst traffic, improving the service

quality.

Description

In the GBSC, the system is overloaded if a large number of MS-originated calls are initiated

or the core network initiates a large number of pagings in a short period. To prevent that the

system is overloaded and ensure the normal operation of the system, the GBSC performs the

flow control and discards some access requests and paging messages.

The operators can divide the cells under the BSC into VIP cells and non-VIP cells as required.

When the GBSC system is overloaded, the call requests initiated in the VIP cells are

preferentially handled. The call requests initiated by the users in the non-VIP cells are




58

processed according to the common flow control algorithm (GBFD-111705 GSM Flow

Control).

Enhancement

None

Dependency


None




The two features are recommended working together:

GBFD-115002 Flow Control Based on Cell Priority

GBFD-115003 Flow control based on User priority

The former one controls uplink flow, and the latter one controls downlink flow.


None

1.7.4 GBFD-115003 Flow control based on User priority

Availability


Summary

Based on the user priority information in eMLPP, the GBSC performs different flow control

policies for users in the case of network congestion. This ensures service availability for

high-priority users.

Benefits

Service availability is ensured for high-priority users in the case of traffic volume bursts.

Description

When congestion occurs, the BSC determines whether a user is a VIP user or not according to

the eMLPP priority of the user. The BSC preferentially processes the paging messages of VIP

users. It processes the paging messages of non-VIP users according to the flow control

algorithm.

To protect the service of high-priority users from being affected by flow control, the GBSC

uses the priority information in eMLPP to classify the signaling priority in flow control. The




59

signaling of high-priority users will not be affected by flow control, whereas the signaling of

low-priority users may be discarded due to flow control.

Flow control will be used in channel assignment, handover, and paging procedures.

Enhancement

None

Dependency


None





GBFD-115001 Enhanced Multi Level Precedence and Preemption (EMLPP)

The two features are recommended working together:

GBFD-115002 Flow Control Based on Cell Priority

GBFD-115003 Flow control based on User priority

The former one controls uplink flow, and the latter one controls downlink flow.


None

1.7.5 GBFD-119907 PS Service in Priority

Availability


Summary

This feature enables telecom operators to provide subscribers with differentiated services.

Subscribers are classified into three priority levels: gold, silver, and copper. The bandwidth

and delay requirements of high-priority subscribers are preferentially guaranteed.

Benefits

Based on subscriber priorities, telecom operators provide differentiated services and charge

subscribers based on flexible policies. For example, a telecom operator charges a gold

subscriber based on traffic whereas charges a silver or copper subscriber at a flat rate.




60

Description

Subscriber priorities are represented by parameters, which are set depending on the traffic

class, ARP, and THP.

If the priority of a subscriber is high, the scheduling priority is also high. As a result, the

subscriber can use services with high bandwidth and low service delay. Interactive,

background, and BE services support differentiated PS services.

Enhancement

None

Dependency


A built-in PCU is required.




None


The MS and SGSN must support this feature.

GBSS14.0 Optional Feature Description 2 Packet Service



61

2 Packet Service

2.1 PS Prime Service

2.1.1 GBFD-114101 GPRS

Availability


Summary

The General Packet Radio Service (GPRS) is a type of end-to-end packet switched service

based on the GSM technology.

Benefits

By providing the data service to the subscriber, the GPRS increases the operators' revenue and

the proportion of the PS services in the mobile services.

Description

Huawei GPRS is implemented by adding GPRS support nodes (GSNs) and packet control

unit (PCU) on the GSM system and upgrading the software. There are two PCU modes:

built-in PCU and external PCU. The GPRS provides quick access of PS services for the

mobile subscribers. Huawei external PCU is connected to the BSC through the Pb interface.

Huawei GPRS has an open system architecture, which facilitates smooth capacity expansion.

The standard interfaces ensure the device compatibility and support the QoS features and the

dynamic allocation of radio resources. In addition, the flexible networking and configuration

save a large amount of CAPEX for the operator in the initial phase of the GPRS service

operation. GPRS provides abundant packet services, for example, mobile Internet access,

e-Commerce (e-Bank and e-Currency), cluster management, remote control/remote

measurement, booking system (hotels, theaters, and airplanes), and group services (stock

information publication).

Huawei GPRS implements mainly three functions: managing radio links and resources,

controlling MS access, and providing routing functions for packet data transmission. The

radio link management includes establishment, maintenance, and release of radio links. The radio resource management includes encoding/decoding, configuration, and multiplexing of




62

the radio packet channel and conversion between the CS service channels and the PS service

channels. In addition, by controlling the access of the MSs, the GPRS solves the problem of

channel contention and assigns channels for MSs according to the requested QoS. The GPRS

system also provides routes to transmit the packet data to the SGSN and receives the

downlink data from the SGSN.

Huawei GPRS uses 16 kbit/s links on the G-Abis interface. When the CS-3 and CS-4 coding

schemes are used, the rate of one PDCH is 15.6 kbit/s and 21.5 kbit/s respectively. Therefore,

when the radio channel is mapped onto the terrestrial channel, one PDCH in CS-3 and CS-4

coding schemes should be mapped onto two 16 kbit/s links. Using the dynamic additional

sub-timeslot technology, Huawei GPRS solves the transmission problem over the G-Abis

interface when the CS-3 and CS-4 coding schemes are used. The dynamic additional

sub-timeslot technology assigns a main 16 kbit/s sub-timeslot statically and an additional 16

kbit/s sub-timeslot dynamically on the G-Abis interface for each PDCH using CS-3 or CS-4.

The dynamic additional sub-timeslot technology has the following features: Any idle 16 kbit/s

sub-timeslot on the G-Abis interface can be used as an additional 16 kbit/s sub-timeslot; the

additional sub-timeslot can be dynamically attached to different main timeslots within the

same site and therefore the usage of additional sub-timeslot is increased based on the

statistical multiplexing rule; the additional sub-timeslot does not need to be the neighbor of

the main timeslot; the data packet is assembled and fragmented through software, which

avoids the upgrade of hardware due to different product specifications; dynamical assignment

of the TCH on the Abis interface can reduce the cost of the transmission on the Abis interface

and therefore reduce the O&M cost of the equipment.

Enhancement

None

Dependency


A built-in PCU, a packet processing board, and a Gb interface board are required.




None



2.1.2 GBFD-510001 Network Operation Mode I

Availability


Summary

The Network Operation Mode I feature together with the Gs interface between the MSC/VLR

and the SGSN support the paging coordination function.




63

Benefits


The Network Operation Mode I together with the Gs interface support paging

coordination and the CS paging when the MS is in packet transfer state.

The Network Operation Mode I feature greatly reduces the signaling load between the

MS and the network, saving and optimizing the radio resources.

Description

The GSM specifications define three network operation modes according to the paging mode

adopted for CS and PS services: Network Operation Mode I, Network Operation Mode II, and

Network Operation Mode III. This feature refers to the Network Operation Mode I.

With this feature, the network sends the CS paging message to the MS on the packet channels.

That is, the network side sends the CS paging message to the MS on the PCCCH, CCCH, or

PACCH. The MS monitors only one paging channel.

If the PCCCH is configured and the MS is in idle state, both the CS paging message and

the PS paging message are sent on the PCCCH.

If the CCCH but not the PCCCH is configured in the cell and the MS is in idle state, both

the CS paging message and the PS paging message are sent on the CCCH.

If the MS is in transfer state, the CS paging message is sent on the PACCH.

The Network Operation Mode I requires the configuration of the Gs interface between the

MSC/VLR and the SGSN because the CS paging message must be transmitted through the

SGSN. For the MS, it listens to only one type of channel to receive the CS paging message.

The Network Operation Mode I feature greatly reduces the signaling load between the MS

and the network, saving and optimizing the radio resources.

Using the Network Operation Mode I, the MS receives the CS paging message on the PACCH

when processing the PS services. Then, the MS stops the PS services and initiates the CS

services.

Enhancement

None

Dependency






None


The Gs interface should be supported by the CN if the paging coordination is supported.




64

2.1.3 GBFD-118901 CS-3/CS-4

Availability


Summary

The CS-3/CS-4 feature fully uses the capability that the GPRS MS already has, increasing the

throughput. The BSC adjusts the coding scheme to a higher level in the area with low error bit

rate according to the transmission quality of the MS.

Benefits


Increases the GPRS service rate, improves the packet service performance in areas where

the EGPRS is not supported, and improves the satisfaction of the subscribers in the entire

GPRS network.

Fully uses the capability that the GPRS MS already has, chooses more suitable coding

scheme (from CS-1 to CS-4) according to reasonable GPRS link control algorithm,

improving the spectrum efficiency.

Description

According to GSM specifications, the GPRS can use four coding schemes, namely, CS-1,

CS-2, CS-3, and CS-4.

Although the CS-1 and CS-2 coding schemes ensure 100% and 90% cell coverage

respectively and meet the co-channel interference requirement C/I = 19 dB, they only have a

data rate of 9.05 kbit/s and 13.4 kbit/s (containing the head of the RLC block) respectively.

The reason is that the half-rate and 1/3 rate bits in the RLC blocks of the CS-1 and CS-2

schemes are used for forward error correction (FEC). This reduces the requirement for C/I and

the transmission rate.

To increase the transmission rate, Huawei provides the CS-3 and CS-4 schemes. The CS-3

and CS-4 schemes provide the transmission rate of 15.6 kbit/s and 21.4 kbit/s (containing the

head of the RLC block) respectively. In addition, the CS-3 and CS-4 schemes have higher

requirements for C/I. During the data transmission, the BSC dynamically adjusts the channel

encoding or decoding scheme according to the retransmission rate of the RLC blocks

transmitted on the uplink or downlink TBF. This improves the transmission rate on the basis

of guaranteed transmission quality and maximizes the use of radio resources.

This feature supports the dynamic conversion among CS-1, CS-2, CS-3, and CS-4.

Enhancement

None

Dependency






65





GBFD-114101 GPRS


None

2.1.4 GBFD-114201 EGPRS

Availability


Summary

The enhanced GPRS (EGPRS) is an enhancement of the GPRS system.

EGPRS uses the 8PSK modulation mode on the RF layer so that the rate of a single channel is

increased. The maximum rate of a single channel is 59.2 kbit/s.

EGPRS adopts new coding schemes MCS-1 to MCS-9.

EGPRS improves the algorithm for controlling the link quality by modifying of the

RLC/MAC protocol at the link layer.

Benefits


Provides high-speed PS services, increases packet capacity, and reduces the delay of PS

services and the congestion rate, improving the service quality and enhancing the user

experience.

Attracts more subscribers of PS services and therefore increases the operators' revenue

by providing more multimedia services.

Description

Compared with GSM, EDGE supports a higher data transmission rate. EDGE provides a set

of enhanced standards for the GSM interfaces and enables the GSM network to carry 3G

services. EDGE consists of EGPRS and ECSD. EGPRS is an enhancement of the GPRS

system. It improves the rate of data channels. EGPRS improves the data transmission

capability of a single timeslot by adding the 8PSK modulation scheme on the Um interface

and improves the data transmission capability of a single user through multislot binding.

Huawei EGPRS has the following features:

Huawei EGPRS supports the coding schemes MCS-1 to MCS-9 in the uplink and downlink,

as listed in the following table.




66

Sch

em

e

Co

de

Ra

te

He

ad

er C

od

e Ra

te

Mo

du

latio

n

Mo

de

RL

C B

lock

s pe

r R

adio

Blo

ck (2

0

ms)

Ra

w D

ata

with

in

on

e R

adio

Blo

ck

Fa

mily

BC

S

Ta

il Pa

ylo

ad

HC

S

Da

ta ra

te

(kb

it/s)

MCS-9 1.0 0.36 8PSK 2 2x592 A 2x12 2x6 8 59.2

MCS-8 0.92 0.36 2 2x544 A 54.4

MCS-7 0.76 0.36 2 2x448 B 44.8

MCS-6 0.49 1/3 1 592

544+48

A 12

6

29.6

27.2

MCS-5 0.37 1/3 1 448 B 22.4

MCS-4 1.0 0.53 GMSK 1 352 C 17.6

MCS-3 0.85 0.53 1 296

272+24

A 14.8

13.6

MCS-2 0.66 0.53 1 224 B 11.2

MCS-1 0.53 0.53 1 176 C 8.8

2. Support for the incremental redundancy (IR) mechanism in the uplink and downlink

EGPRS adopts two modes for controlling the link quality: link adaptation (LA) and IR.

Compared with GPRS that uses only the LA mode, EGPRS uses both the LA mode and the IR

mode. The working principle of the IR mechanism is as follows: Generally, the transmitter

uses the coding scheme with a high rate for data transmission; however, the coding scheme

with a high rate always has a weak protection capability. If the data is received incorrectly, the

transmitter retransmits additional coding information. The receiver combines the new

information with the historical information and then performs decoding. This procedure is

repeated until the decoding is successful.

3. Support for dynamic adjustment of EGPRS coding schemes in the uplink and downlink

The dynamic adjustment of EGPRS coding schemes is similar to the dynamic adjustment of

GPRS coding schemes. The GBSS sends the system information to the MS. The MS

calculates the bit error probability (BEP) in the downlink and reports the result to the GBSS

through the measurement report. The GBSS then adjusts the EGPRS coding schemes in the

uplink and downlink based on the downlink BEP.

4. Dynamic additional sub-timeslot technology

The dynamic additional sub-timeslot technology solves the problem of transmission over the

G-Abis interface using MCS-3 to MCS-9. The dynamic additional sub-timeslot technology

statically assigns one main 16 kbit/s sub-timeslot and dynamically assigns one to three

additional 16 kbit/s sub-timeslots on the G-Abis interface for each PDCH using MCS-3 to

MCS9. Using the dynamic additional sub-timeslot technology, the EGPRS BSS does not need

to upgrade the hardware of the BTS, BSC, and PCU for supporting MCS-3 to MCS-9. In




67

addition, EGPRS maximizes the multiplexing mode over the G-Abis interface, saving the

investment on the transmission devices over the G-Abis interface.

The strategy for allocating the 16 kbit/s sub-timeslots for different EGPRS services is listed in

the following table.

Coding Scheme Number of 16 kbit/s Timeslots Allocated over the Abis Interface

MCS-1 to MCS-2 1

MCS-3 to MCS-6 2

MCS-7 3

MCS-8 to MCS-9 4

Enhancement

None

Dependency






None


The SGSN, GGSN, and MS must support this feature.

2.1.5 GBFD-113101 PDCH Dynamic Adjustment

Availability


Summary

With this feature, fixed channels do not need to be configured for the PS services, the TCH

and the PDCH can be automatically converted as required.

Benefits





68

Reduces the impact of GPRS services on the GSM speech services, decreases the

maintenance and configuration workload, and increases channel usage and network

capacity.

Improves the performance of the PS services and increases the operators' revenue.

Description Packet channel types

The PDCH is classified into static PDCH and dynamic PDCH based on the bearer

services (CS services or PS services).

The static PDCH is used for the PS services only.

The dynamic PDCH is a TCH during the initialization process. In the case of packet

access, the TCH and the PDCH can be dynamically converted.

PDCH dynamic adjustment

The static PDCH is used for the PS services only. The dynamic PDCH is a TCH during

the initialization process. When the packet resources are insufficient, the PCU requests

dynamic PDCHs from the BSC for the PS services. When the circuit resources are

insufficient, the BSC requests dynamic PDCHs that are used as TCHs from the PCU.

In this manner, the channel resources are flexibly used as required. Therefore, the usage

of resources is increased, and the complexity of PDCH configuration and the workload

of maintenance and configuration are reduced. In addition, the impact of unreasonable

PDCH configuration on the service performance is reduced.

Enhancement

GBSS7.0

PDCH Preemption Priority: In the latter period of the GSM network development, the

requirements for the PS services are preferentially met because of the significant increase in

the data service demand. Huawei PCU equipment supports three types of PDCH preemption

priorities: all dynamic channels preemptable, packet control channels unpreemptable, and all

dynamic channels carrying services unpreemptable. This application enhancement optimizes

the performance of the PS services by limiting channel preemption of the CS services. The

operators can implement different packet allocation strategies by configuring preemption

priority.

All dynamic channels preemptable: The CS services can preempt all dynamic channels.

Packet control channels unpreemptable: The CS services can preempt all the other dynamic

channels except the packet control channels.

All dynamic channels carrying services unpreemptable: The CS services cannot preempt all

the dynamic channels carrying services.

GBSS8.0

Overall Dynamic PDCH Availability: Except for static PDCHs, all the other channels can be

converted in real time based on the situation of the PS services and the CS services. If

required, TCHs can be converted to PDCHs for the PS services. With this application

enhancement, more PDCHs can be converted when the CS services are not busy. This can

alleviate the decrease in the transmission rate due to PDCH multiplexing. This flexible

mechanism can maximize the channel usage and optimize the distribution of PDCHs and

TCHs. In addition, the network planning is simple and therefore you can expand the capacity

if required.




69

Dependency







GBFD-114101 GPRS

GBFD-114201 EGPRS


None

2.1.6 GBFD-510002 Gb Over FR

Availability


Summary

As a traditional networking mode, the Gb over FR feature enables the operator to deploy the

network in frame relay (FR) transmission mode between the BSC and the SGSN.

Benefits


This feature is compatible with the CN equipment in the existing network.

This feature enables the operator to fully utilize the existing network in FR transmission

mode.

Description

This feature complies with the 3GPP protocols.

The Gb interface provides connections between the BSS and the SGSN to send the

information related to cell management and handovers in routing areas and transmit the data

between the MS and the SGSN. Traditionally, the Gb interface uses the FR transmission mode

to provide the logical link connection. Data is transferred through the network service virtual

connection (NS-VC). The NS-VC is the permanent virtual channel (PVC) in FR.

Huawei GBSS supports the FR networking over the Gb interface in the E1/T1 direct

transmission mode or the FR transmission mode and supports configuration of multiple PVCs

between the BSS and the SGSN. In addition, Huawei BSS manages these PVCs and supports

load sharing among them.

The BSC that supports Gb over FR requires no hardware upgrade. Only software upgrade is required to deploy the SGSN pool.




70

The BSC supports the FR transmission mode and the IP transmission mode for the

communication between the BSC and the SGSN. These two modes can work simultaneously.

Enhancement

None

Dependency






None


None

2.1.7 GBFD-119201 11-Bit EGPRS Access

Availability


Summary

The Packet Channel Request message is an 8- or 11-bit access burst. This feature supports the

11-bit EGPRS access. The 11-bit access burst contains the multislot capability of an MS and

therefore enables rapid allocation of more channels. The EGPRS MS supports one-phase

11-bit access. This shortens the access delay.

Benefits

This feature shortens the access delay and increases the access rate of the EGPRS MS,

increasing the subscriber satisfaction.

Description

With this feature, the EGPRS MS can send the 11-bit channel access signaling request. In this

manner, the system implements only one-phase access. That is, the system can immediately

assign signaling for the MS to establish the uplink TBF and then transmit data. Before this

feature is used, two-phase access is required.

Moreover, this feature shortens the time for TBF establishment and improves the performance

of small-sized data transmission (such as the TCP handshake).

Enhancement

None




71

Dependency







GBFD-114201 EGPRS



2.1.8 GBFD-119203 Extended Uplink TBF

Availability


Summary

This feature ensures that the TBF is not released when no data is transmitted. In this manner,

the TBF does not need to be re-established after the data is transmitted again. Therefore,

frequent TBF establishment and releases are avoided.

Benefits

This feature reduces the cost for establishing the uplink TBF, shortens the data transmission

time in the uplink, and increases the uplink rate.

Description

After the uplink data is sent, the common uplink TBF is released immediately whereas the

extended uplink TBF enters the inactive period. If there is new data to be transmitted, the TBF

in inactive period enters the active period for data transmission. If the inactive period timer

expires and there is no data to be transmitted, the TBF is released. The inactive period timer is

an adjustable parameter pertaining to network optimization.

With this feature, the throughput rate of the services with unstable data flow such as webpage

browsing and email sending is improved.

Enhancement

None

Dependency






72





GBFD-114101 GPRS

GBFD-114201 EGPRS



2.1.9 GBFD-119204 Dynamically Adjusting the Uplink MCS Coding

Availability


Summary

This feature enables the BSS to support coding schemes MCS-1 to MCS-9 and dynamically

adjust the coding scheme based on the radio quality.

Benefits

This feature increases the uplink rate of the EGPRS users, enhances the user experience, and

improves the network quality.

Description

The requirements for the radio transmission quality vary with the transmission rate of the

coding schemes. The higher the transmission rate, the higher the requirements for the radio

transmission quality. During the data transmission process, the BSC dynamically adjusts the

coding scheme based on the radio quality to maximize the radio resource usage and the

transmission rate with guaranteed transmission quality.

Currently, the BSS supports nine coding schemes MSC-1 to MCS-9. The aim of this feature is

to dynamically adjust the uplink rate of the EGPRS user based on the network status. With

this feature, the BSC dynamically adjusts the coding scheme adopted by the PDCH based on

the uplink measurement report from the BTS. In this manner, the PDCH can quickly adapt to

the changes in the radio condition and therefore the uplink throughput is increased.

Enhancement

None

Dependency






73





GBFD-114201 EGPRS


None

2.1.10 GBFD-119205 Dynamically Adjusting the RRBP Frequency

Availability


Summary

With this feature, the relative reserved block period (RRBP) frequency is dynamically

adjusted according to the status of the uplink TBF and the downlink TBF. The data blocks

with the RRBP flag in the downlink are sent at different intervals.

Benefits


Optimizes the uplink access rate of PS services, improving the performance of the TCP

services such as FTP downloading by increasing the rate of sending the TCP ACK

message. As a result, the user experience is enhanced.

Reduces unnecessary data flow in the uplink and the impact on other users on the same

PDCH.

Description

This feature optimizes the RRBP frequency based on two factors: uplink TBF status and the

phase of delayed downlink TBF release.

Uplink TBF status and RRBP frequency

During the downlink transmission process, the BSC periodically sends data blocks with

RRBP flag to reserve uplink resources for the MS to respond with the PACKET

DOWNLINK ACK/NACK message to report the receiving status of the downlink data.

When the MS needs to send data in the uplink but the uplink TBF does not exist, the MS

can carry the channel request information in the PACKET DOWNLINK ACK/NACK

message to initiate the access. Therefore, if the frequency of sending the data blocks with

RRBP flag is increased at this time, the access rate of the MS can be increased.

On the other hand, the PACKET DOWNLINK ACK/NACK message seizes the uplink

bandwidth. Therefore, when the uplink TBF already exists, the uplink expenditure is

reduced and the uplink data bandwidth is increased if the frequency of sending the data

blocks with RRBP flag is reduced.

Phase of delayed downlink TBF release and RRBP frequency




74

The MS generally has a demand for sending uplink data in the earlier period of the

delayed downlink TBF release after the data transmission in the downlink is complete.

At this time, the BSS system uses a high frequency for sending the data blocks with the

RRBP flag. In the latter period of the delayed downlink TBF release, there is less data to

be sent in the uplink. At this time, the BSS system uses a low frequency for sending the

data blocks with the RRBP flag.

This feature dynamically adjusts the frequency for sending the data blocks with the

RRBP flag based on the uplink TBF status and the phase of delayed downlink TBF

release. When the uplink TBF exists and the delayed TBF release is in the latter period, a

low frequency can be used to save the uplink bandwidth. When the uplink TBF does not

exist and the delayed TBF release is in the earlier period, a high frequency can be used to

increase the uplink access rate of the MS.

Enhancement

None

Dependency






None



GBFD-114101 GPRS

GBFD-114201 EGPRS


None

2.1.11 GBFD-119302 Packet Channel Dispatching

Availability


Summary

The GPRS system uses only the GMSK modulation scheme whereas the EGPRS system uses

the GMSK and 8PSK modulation schemes. When EGPRS downlink services and GPRS

uplink services use the same packet channel, the EGPRS downlink data blocks with the USF

should be used to schedule the GPRS uplink services. In this case, the EGPRS downlink data

blocks can use only the GMSK modulation scheme. This greatly affects the downlink

throughput of the EGPRS MS. With this feature, the operator can separate the EGPRS




75

services from the GPRS services, effectively increasing the downlink throughput of the

EGPRS MS.

Benefits

This feature reduces the probability that the EGPRS services and the GPRS services use the

same channel, increasing the EGPRS service rate, improving the entire network performance,

and enhancing the user experience.

Description Types of Preferred Channels for Packet Services

There are five types of preferred channels: EGPRS dedicated channel, EGPRS preferred

channel, common EGPRS channel, GPRS channel, and non-GPRS channel.

EGPRS dedicated channels serve only EGPRS MSs.

EGPRS preferred channels serve EGPRS MSs in preference to GPRS MSs but can be

used by GPRS MSs when the channels are not occupied by EGPRS MSs. When an

EGPRS MS requests an EGPRS preferred channel, the GPRS MSs that occupy the

EGPRS preferred channels should be transferred to other channels. EGPRS MSs and

GPRS MSs cannot use the same EGPRS preferred channel.

Common EGPRS channels serve either GPRS MSs or EGPRS MSs, whichever occupies

the channel first.

GPRS channels serve GPRS MSs. If a cell is not configured with EGPRS channels,

EGPRS MSs in the cell use these channels to process GPRS services.

Non-GPRS channels are channels that are not used for the PS services.

Channel Allocation Principles

When configuring the channel type on the TRX, you can select the channel type from the

GPRS preferred channel types.

When the BSS allocates PDCHs, the preferred channel type varies with the specific

packet services.

For GPRS services, the channels are preferentially assigned in the following order:

GPRS channels, common EGPRS channels, and EGPRS preferred channels.

For EGPRS services, the channels are preferentially assigned in the following order:

EGPRS dedicated channels, EGPRS preferred channels, and common EGPRS channels.

Multiplexing of common EGPRS channels may occur when the GPRS MS uses the

uplink channel and the EGPRS MS uses the downlink channel. To avoid this, you can set

Allow E Down G Up Switch to Close. If you want to avoid this situation do not

configure common EGPRS channels.

Channels should be used based on the type of the preferred channel. For example, if the

channels on the TRX that supports EGPRS are configured as GPRS channels, these

channels can be used for only GPRS services. EGPRS dedicated channels can be

configured only as static channels whereas the other three preferred channels can be

configured as static or dynamic channels.

Enhancement

None




76

Dependency







GBFD-114201 EGPRS


None

2.1.12 GBFD-119303 Load Sharing

Availability


Summary

Based on the traffic load on the PDCHs, load sharing applies to the dynamic adjustment of the

MS distribution on the PDCHs to improve the channel utilization and single-user PS service

rate.

Benefits

This feature helps improve the channel utilization and PS service rate.

Description

The strategy for load sharing includes the following three parts:

When an MS accesses the network, the system preferentially assigns a TRX with a light load

to the MS to adjust the load distribution between TRXs.

When the MS provides PS services, the system assigns the MS a PDCH or PDCHs with a

light load. The occupancy of channel resources varies during the transmission. For example, if

the MS releases channel resources when the service ends, some TRXs or PDCHs are idle. If

the MS accessing the network is not shifted from the channel with heavy load to the channel

with a light load, the channel resources are wasted. According to the load on the PDCHs, the

BSS shifts the MS carried on the PDCH with a heavy load to the one with a light load.

Therefore, load sharing is implemented and the single-user rate increases.

When the channel is released, the system adjusts the load distribution between channels

according to the traffic load on each channel to ensure load balance on the PDCHs, optimally

utilizing channel resources.




77

Enhancement

GBSS8.1

Load sharing during the release of radio resources: This function enhances the load balance

between TRXs when radio resources are released. Therefore, the resources on all the TRXs

are reassigned in the cell. That is, the MSs carried on the TRXs with a heavy load are assigned

to those with a light load, and then the MSs carried on the PDCHs with a heavy load are

assigned to those with a light load so that the load balance between all the TRXs in the cell is

realized and the channel resources are optimally utilized. For example, an MS transmits data

for a long time. During the data transmission, if radio resources are released by other MSs, the

BSC determines whether the TRX used by the MSs that release radio resources are idle. If the

TRX is idle, the MS performing long-time data transmission is reassigned with the channels

on the idle TRX. Therefore, the throughput of the MS is increased.

When the traffic load of the GPRS channels decreases, some GPRS MSs are shifted from the

EGPRS channel to the GPRS channels to increase the channel utilization and minimize the

impact on the EGPRS services.

Dependency







GBFD-114101 GPRS

GBFD-114201 EGPRS


None

2.1.13 GBFD-119501 Adaptive Adjustment of Uplink and Downlink Channels

Availability


Summary

The uplink and downlink channel adaptive adjustment implements dynamic assignment of the

number of uplink and downlink channels for the MSs based on the uplink and downlink

service data flow.




78

Benefits

In the case of the services that are processed on both the uplink and downlink such as ping

large packets and Push to Talk over Cellular (PoC), this feature helps to reduce the system

transmission delay.

In the case of the downlink-preferred services such as FTP download, this feature helps

improve the downlink data throughput.

In the case of the uplink-preferred services such as e-mail sending, this feature, used together

with extended dynamic allocation (EDA), helps improve the uplink data throughput.

Description

The BSS measures the data throughput of uplink and downlink of each temporary block flow

(TBF) regularly to determine the current service type of the TBF.

If the downlink-preferred service is performed, the BSS assigns as many downlink timeslots

as possible to the MS. For an MS with multislot class of 12, the BSS uses the 4+1 DL/UL

timeslot configuration preferentially.

If the uplink-preferred service is performed, the BSS assigns as many uplink timeslots as

possible to the MS. For an MS with multislot class of 12, the BSS uses the 1+4 DL/UL

timeslot configuration preferentially used together with EDA.

If the service processed on both the uplink and downlink is performed, the BSS tries to assign

the timeslots of uplink and downlink asymmetrically to the MS. For an MS with multislot

class of 12, the BSS uses the 3+2 DL/UL timeslot configuration preferentially.

Enhancement

None

Dependency







GBFD-114101 GPRS

GBFD-114201 EGPRS


None




79

2.2 PS Service Enhancement

2.2.1 GBFD-119901 Streaming QoS(GBR)

Availability


Summary

For the streaming class services, after the QoS mechanism is introduced, the BSC allocates

radio resources according to the guaranteed bit rate (GBR) of the QoS to ensure the data

transmission rate. When the radio resources are insufficient, the subscribers with high priority

can preempt the radio resources of the subscribers with low priority.

Benefits


Ensures sufficient and stable bandwidth for the streaming services.

Ensures preferentially the bandwidth requirement and service experience of the

subscribers with high priority when radio resources are insufficient.

Helps the operator to take flexible charging policies.

Description

This feature supports the packet flow management (PFM) procedure, which manages packet

flow context (PFC). The PFM process includes the establishment, modification, and deletion

of the PFC. In addition, the BSC obtains or modifies the attributes of QoS through the PEM

procedure.

This feature is enabled to support streaming and push to talk over cellular (PoC) services. If

the MS supports GBR, the resources are allocated according to the GBR of the QoS. If the

MS does not support GBR, the resources are allocated according to the BEST EFFORT. The

BSC dynamically allocates Um interface resources to the MS based on the radio environment

so that the bandwidth of the MS is permanently greater than or equal to the GBR. When the

radio resources on the Um interface are insufficient, the GBR is reduced. When the radio

resources on the Um interface are sufficient, the reduced GBR is restored. When the BSC

needs to reduce or restore the GBR, it requests the SGSN to modify the GBRs through the

PFM procedure.

Enhancement

GBSS8.1

Streaming class service resource preemption: If the BSC cannot offer sufficient transmission

resources for the high-priority subscribers of the streaming class service, the transmission

resources of the low-priority subscribers of the streaming class service will be preempted. If

the radio resources are still insufficient after preemption, the GBR is reduced. If the radio

resources are sufficient, the reduced GBR is restored. This feature ensures that the

high-priority subscribers of the streaming services preferably use the radio resources,

reducing the possibility that the packet service access fails due to insufficient radio resources

on the Um interface and improving the user experience.




80

Dependency






PS-related features are dependent on the following features (the individuals are not listed

here):

GBFD-114101 GPRS

GBFD-114201 EGPRS


The MS and SGSN must support this feature.

2.2.2 GBFD-119902 QoS ARP&THP

Availability


Summary

After the QoS mechanism is introduced, the BSC allocates radio resources to the users

according to the allocation/retention priority (ARP) and traffic handle priority (THP) of the

QoS. The higher-priority users enjoy more radio resources and higher radio bandwidth. To be

compatible with R97/R98 QoS, this feature supports the mapping between R97/98 QoS and

R99 QoS.

Benefits

With this feature, the operator allocates the radio resources according to different service

types and user priorities. As a result, the user with higher priority can seize more bandwidth

and enjoy higher data rate and better quality of service. This feature has the following

benefits:

High-priority users can enjoy more bandwidth whereas low-priority users are subject to

bandwidth constraint.

The bandwidth allocation mechanism is more flexible because the operator can allocate

the radio resources according to different service types and user priorities.

The operator can formulate flexible charging policies.

Description

The BSC allocates the radio resources to the MS according the ARP and THP of the QoS. The

higher-priority users enjoy more radio resources and higher radio bandwidth.

Interactive services: The BSS allocates the radio resources according to the ARP and THP of

the QoS. If the ARPs of the users are the same, the users with higher THP are allocated more




81

radio resources. If the THPs of the users are the same, the users with higher ARP are allocated

more radio resources.

Other services: The BSS allocates the radio resources according to the ARP of the QoS. The

users with higher ARP can be allocated more radio resources.

For the services that do not support the QoS, the BSS allocates the radio resources according

to the BEST EFFORT.

Enhancement

GBSS8.1

Mapping between R97/R98 QoS and R99 QoS: If the MS supports only the R97/R98 QoS,

that is, the MS does not support the GBR, the BSC maps the R97/R98 QoS to the R99 QoS

according to the 3GPP specifications. After the precedence class of the R97/R98 QoS is

mapped as the ARP of the R99 QoS, the BSC allocates the radio resources based on the ARP.

Configuration of the radio resource allocation priorities: The priorities are configured on the

basis of the service types of the QoS, ARP, and THP. For the services that do not support the

QoS, the priorities are allocated according to the BEST EFFORT. The BSC allocates the radio

resources according to the user priorities. The higher-priority users are allocated more radio

resources. This feature enables the operator to allocate the radio resources according to

different service types and user priorities and therefore the bandwidth allocation mechanism is

more flexible.

Dependency






None


The MS and the SGSN must support this feature.

2.2.3 GBFD-119904 PS Active Package Management

Availability


Summary

With this feature, the server at the application layer adjusts the transmit rate based on the

bandwidth that can be provided by the radio links, avoiding IP packet loss and timeout of the

IP packet transmission. As a result, the performance of the services such as large-sized email

sending, webpage browsing, and file transfer is improved. In addition, the packet performance

is greatly improved when multiple services are processed simultaneously.




82

Benefits


Improves the downlink throughput when the quality of the radio link is poor.

Reduces the download time when multiple web pages are downloaded simultaneously.

Ensures high bandwidth usage, reduces the delay of the packet service, and enhances the

fairness of the bandwidth seizure of various packet service flows.

Improves the performance of the packet service. For example, when large-sized files are

involved in the packet service, such as FTP downloading and email sending, this feature

shortens the service delay and therefore improves the user experience.

Description

Compared with the reactive queue management (a technique which drops the overflowed

packets only when the queue is full), this feature provides active queue management and

real-time monitoring of the buffer queue to monitor the network congestion. Once the

network is congested, the system drops the data packets proactively and adjusts the sending

rate at the TCP sending end to maintain the buffer queue at a certain length to reduce the

congestion.

Therefore, the throughput of the TCP service is maximized, the data buffer size is reduced,

and the interactive time and response time of the services such as webpage browsing are

saved.

In GSM, the packet service uses the TCP/IP protocol in most cases. When multiple

connections co-exist, the strong connection in a system may result in long transmission time

over the weak connection. For example, a subscriber clicks a button on an HTTP webpage

when FTP downloading is in progress. In such a case, a long time elapses before the

corresponding webpage is displayed because the link resource is occupied by the FTP service.

The PS active package management is applicable to scenarios where congestion may occur

because of bandwidth limitation. It can reduce the network congestion caused by the TCP data

flow, so the service throughput is increased and the service delay is decreased.

The PS active package management performs queue management for only interactive services,

background services, and services that do not support the QoS. The queue management is not

performed for real-time services, such as conversational services and streaming services.

Enhancement

None

Dependency






None




83


None

2.2.4 GBFD-119905 PoC QoS

Availability


Summary

The push to talk over cellular (PoC) service is a type of real-time packet service that has high

bandwidth and delay requirements. To guarantee the service quality and real-time

performance, Huawei GBSS provides the QoS measures such as GBR, reduced data

transmission delay, and balanced uplink and downlink channel allocation.

Benefits

This feature guarantees the real-time performance of the PoC service, improves the voice

quality of the PoC service, and enhances the user experience. It provides the operator with

competitive advantages and enables the operator to provide differentiated services for data

service subscribers. It also increases the service revenue.

Description

The PoC service is a type of group call service implemented on the GSM network. The PoC

service adopts the packet switching technology and is carried on the GPRS/EGPRS network.

The PoC service involves subscriber authentication, conversation establishment, media

dispatching, charging, and strategy control, most of which run on the PoC server in the CN.

The PoC signaling and voice data are carried over GPRS/EGPRS. The GBSS transparently

transfers these packets to the CN for further processing. In contrast to the packet service, the

PoC service carries speech signals and requires low transfer delay. If the transfer delay is high,

the user experience is affected. Huawei GBSS is able to identify the PoC service and provides

certain measures to guarantee the QoS. These measures include GBR, reduced data

transmission delay, and balanced uplink and downlink channel allocation.

GBR: The resources are allocated based on the GBR. If the GBR cannot be guaranteed, it is

re-negotiated and the resources are then allocated based on the negotiated GBR.

Reduced data transmission delay: The services are scheduled based on the priorities. The

high-priority services are preferably scheduled and the services with the same priority are

scheduled in turn.

Balanced uplink and downlink channel allocation: In most cases, the PoC service requires the

uplink TBF and downlink TBF simultaneously and symmetrical traffic in the uplink and

downlink. Therefore, the balanced uplink and downlink channel allocation enables a similar

number of PDCHs to be allocated in the uplink and downlink if the multislot class of the MS

permits and if the requirements of GBR are met.

Enhancement

None




84

Dependency







GBFD-119901 Streaming QoS(GBR)



2.2.5 GBFD-119906 Conversational QoS

Availability


Summary

Conversational QoS refers to the QoS of conversational services.

This feature means that when an MS subscribes to a network, the services on the MS are

registered as conversational services. The BSC processes the services on the MS as

conversational services according to the registered QoS information, provided that the MS

supports the reduced latency. In this way, the service transmission delay does not exceed 80

ms and the end-to-end delay does not exceed 300 ms, meeting the high requirements of

conversational services such as VoIP, PoC, and Gaming for the transmission delay.

Benefits

With the development of IP-based services such as VoIP, PoC, and Gaming, the users'

requirements for the service transmission delay become increasingly higher. The QoS of

conversational services can achieve enhanced QoS and improved user experience. The details

are as follows:

Helping operators to achieve enhanced QoS of PS services, improve the competitiveness

of GSM products in the PS domain, and attract more VIP users

Enhancing user experience and improving the core competitiveness of operators

Increasing operators’ revenues by improving the performance of PS services and

implementing value-added services such as VoIP and PoC

Description

The conversational service is a type of real-time service and has high requirements for the

transmission delay. As specified by the related protocol, the transmission delay of

conversational services cannot exceed 80 ms. In general, to ensure user satisfaction, the

end-to-end delay for VoIP services cannot exceed 300 ms.




85

Conversational services use the RTTI TBF so that the requirements of the conversation QoS

for transmission delay are met. The scheduling period of radio blocks based on the BTTI TBF

is 20 ms and the scheduling period of radio blocks based on the RTTI TBF is 10 ms. If the MS

does not support the reduced latency, the BSC also allows the MS to run conversational

services. The BSC allocates the BTTI TBF to the MS and tries to meet the requirement of

conversation QoS for the transmission delay. Because the capability of the MS is limited, the

BSC is unable to guarantee that the MS can meet the requirement of conversation QoS for the

transmission delay.

Because PS services are transparently transmitted on the BSC, the BSC cannot exactly

identify the service type of the MS. Therefore, the BSC can determine the service type only

based on the information that the MS registers in the HLR.

The criteria for checking whether the services on the MS meet the QoS of conversational

services are not the actual services running on the MS but the following two conditions:

1. Whether conversational services are registered during the registration of the MS

2. Whether the MS supports the reduced latency

Only when the previous two conditions are met, the transmission delay of services on the MS

over the Um interface may meet the requirement of Conversation QoS.

If the MS supports the reduced latency, employ the policy of binding the RTTI feature and the

FANR feature. The RTTI feature can reduce RTT, and the FANR feature can greatly reduce

the response time of the MS in case that the signal quality on the Um interface is poor.

Because the current GBSS version supports the RTTI and FANR feature only in IP/HDLC

transmission mode, Conversation QoS can be optimally supported in IP/HDLC transmission

mode.

Enhancement

None

Dependency



This feature applies only to IP/HDLC networking scenarios, the PEUa/POUc boards are

needed as Abis interface board, and the DPUc boards are needed in GMPS/GEPS subrack.





GBFD-510805 Latency Reduction






86

2.2.6 GBFD-116201 Network-Controlled Cell Reselection (NC2)

Availability


Summary

The network-controlled cell reselection (NC2) refers to the situation that the MS in packet

transfer mode can be controlled by the network to reselect a cell according to the

measurement report.

Benefits

Based on the receive quality of the MS and receive level of the neighboring cell, this feature

enables the network-controlled MS to reselect a cell with better receive level. Therefore, the

subscriber can obtain better packet service, the performance of the packet service in the whole

network is improved, and the resource usage is increased.

Description

In NC2 mode, the network instructs the MS to perform cell reselection. In this manner, the

MS can reselect a better cell because the network has a clearer view of the actual network

condition than the MS does. Therefore, a better network performance is achieved.

When the MS is in packet transfer mode, the network helps to reselect a cell with better

receive level and lighter load for the MS based on the measurement report and the network

load condition.

The NC2 is triggered under the following scenarios:

1. The downlink receive quality of the MS drops rapidly.

2. The reselection does not occur and the number of received packet measurement reports

reaches a certain threshold.

In these cases, the network helps the MS to reselect a cell with better receive level. As a result,

the user experience is enhanced, and the performance of the packet service in the whole

network is improved.

Enhancement

GBSS8.1

Inter-BSC NC2: The network can select the neighboring cell controlled by another BSC as the

target cell and initiate the cell re-selection procedure.

NC2 based on cell load: When the load of PS services in the cell exceeds a specified threshold,

the MS that meets the requirement of neighboring cell level threshold is reselected to the

neighboring cell with light load.

Support for NC2 of the target cell of the WCDMA system: The network can select the target

cell of the WCDMA system for cell reselection based on the measurement reports.




87

Dependency






None



2.2.7 GBFD-116301 Network Assisted Cell Change (NACC)

Availability


Summary

NACC refers to network-assisted cell reselection. To implement rapid PS access after cell

reselection, the BSC sends the system information about the target cell to the MS before cell

reselection. Therefore, the service interruption time due to the cell reselection is minimized.

Benefits


Increases the cell reselection speed, minimizes the service interruption time due to the

cell reselection, and enhances the user experience.

Adheres to satisfy the services that have higher requirements for delay and throughput

(such as the streaming service).

Increases the system capacity because the resources of the original cell can be released

rapidly after the cell reselection.

Description

The NACC feature enables the MS to access the new cell rapidly after cell reselection and

perform data transmission without receiving the complete system information.

The NACC feature does not control the cell reselection of the MS, but notifies the network to

send the system information in advance when the MS decides to reselect a cell and delays the

cell reselection. In this manner, this feature increases the cell reselection speed of the MS,

greatly reducing the data transmission interruption time due to cell reselection.

Because the cell reselection speed is increased, the MS can rapidly notify the SGSN. The

SGSN can then rapidly detect that the cell reselection occurs. As a result, the resources of the

original cell can be quickly released to other users and therefore the system capacity is

increased.




88

Enhancement

GBSS8.1

Support for resource reservation in the target cell: When the network receives the cell

reselection decision of the MS, it reserves the required radio resources in the target cell to

ensure that the MS can obtain sufficient resources for service recovery after reselection.

Support for NACC between BSCs or between BSC and RNC: This application enhancement

can reduce the delay of cell reselection between BSCs or between the BSC and the RNC. It

requires the BSC to support the RIM procedure to obtain the system information of the

external cell. During cell reselection, if the BSC has the system information of the external

cell, it sends the system information to the MS. Otherwise, the BSC initiates the RIM

procedure to request the system information and save the system information for future use.

Dependency


None





GBFD-114101 GPRS or

GBFD-114201 EGPRS



2.2.8 GBFD-119801 Packet SI Status (PSI)

Availability


Summary

With this feature, the MS requests the system information that it requires by sending the

Packet SI Status message to the BSC to reduce the service interruption time or service delay.

Benefits

This feature is used together with the NACC to reduce the interruption time of the packet

service due to cell reselection, improving the packet service quality and enhancing the user

experience.




89

Description

The MS in packet transfer mode notifies the BSC of the system information it requires by

sending the Packet SI Status message to the BSC. The BSC then sends the system information

to the MS on the PACCH. The MS uses the obtained system information for the packet

service being processed to avoid the service interruption or delay.

This feature is used together with the NACC to speed up the cell reselection and reduce the

service interruption time.

Enhancement

None

Dependency


None




None



2.2.9 GBFD-119305 BSS Paging Coordination

Availability


Summary

When no Gs interface between the MSC/VLR and SGSN is configured and the MS is in

packet transfer state, the network sends CS paging messages through the PACCH. Then, the

MS in packet transfer state can respond to the CS paging message.

Benefits

With this feature, the MS in packet transfer state can receive the CS paging message, avoiding

the drop of network paging rate when the PS services are performed.

Description

When the common class B MS is in packet transfer state, it only listens to the paging message

on the PACCH. When no Gs interface is configured, the MS in packet transfer state cannot

respond to the CS paging message because the CS paging message is sent on the PCH. This

problem can be solved through BSS paging coordination.




90

After the BSC receives a CS paging message over the A or Gb interface, BSS paging

coordination enables the BSC to query whether the MS is performing PS services according

to the IMSI carried in the paging message. If the MS is in packet transfer state, the BSC sends

a paging message to the MS through the PACCH; if the MS is in idle state, the BSC sends a

paging message to the MS through the PCH.

BSS paging coordination is independent of the Gs interface between the MSC/VLR and

SGSN and is independent of Network Operation Mode I. The GBSC independently

determines whether the paging message is sent on the PCH or on the PACCH. If no Gs

interface is configured in a network with large amount of PS services, BSS paging

coordination helps increase the paging success rate.

Enhancement

None

Dependency







GBFD-114101 GPRS

GBFD-114201 EGPRS


MS should support.

2.2.10 GBFD-119502 PS Handover

Availability


Summary

The PS handover involves the internal inter-cell handover and the external inter-cell handover

(including the inter-RAT handover).

Benefits

The interruption period of PS services during handover is shortened, ensuring the QoS of PS

services especially conversational services. Therefore, operators can provide more

value-added services such as VoIP, PoC, and Gaming to increase revenue.




91

Description

The PS handover complies with the related 3GPP R6 protocols, mainly the 3GPP TS 44.060,

48.018, and 43.129.

Conversational services have high requirement for the interruption period and cell reselection

cannot meet this requirement. With the introduction of PS handover, before the MS is handed

over, radio resources are allocated to the MS in the target cell. This greatly decreases the

latency of cell change and reduces the service interruption period to less than 150 ms. Besides,

PS handover takes into account factors such as the signal level and the load in the neighboring

cells in advance and therefore ensures the success rate of PS handover and the throughput of

the new cell. In this way, QoS is ensured.

The PS handover involves the internal inter-cell handover and the external handover

(including the inter-RAT handover). In addition, the PS handover involves also the handover

triggered by the MS in NC0 or NC1 mode and the handover triggered by the network side in

NC2 mode.

The GBSS provides performance statistics related to PS handover. Based on the types of PS

handover, measurement counters are classified into intra-RAT handover counters, inter-RAT

handover counters.

Enhancement

None

Dependency






None



2.2.11 GBFD-119503 Early TBF Establishment

Availability


Summary

The early TBF establishment is a function introduced in 3GPP R7. In the early TBF

establishment feature, the TBF is allocated to the MS prior to data transfer. Therefore, the

service access delay is shortened.




92

Benefits

In the early TBF establishment feature, the delay of the uplink data is decreased by as much

as hundreds of milliseconds (about the time for TBF establishment) compared with that in the

traditional TBF establishment. This improves the user experiences of the session services such

as the PoC service and the VoIP service.

Description

The packet transfer delay is a key index of the packet services, particularly the delay sensitive

session services. The early TBF establishment feature supports the pre-allocation of the TBF

before the MS sends data. In this way, the transmission delay of the uplink data is reduced.

Generally, the MS applies for the TBF resources only when the MS has data to transmit. The

BSC then starts to allocate the TBF resources. In the early TBF establishment feature, the

TBF resource application is triggered prior to the data transfer of the MS. The BSC

pre-allocates the uplink TBF resources for the MS and sets the TBF to inactive state. In a

specified period, the MS can send the data directly without the need for establishing the TBF.

After the specified period, the BSC releases the TBF to save the packet transmission

resources.

Enhancement

None

Dependency






GBFD-119203 Extended Uplink TBF



2.2.12 GBFD-119504 PS Power Control

Availability


Summary

This feature enables the BSC to adjust the transmit power of the BTS according to the link

quality of the Um interface. In this way, the desirable link quality can be ensured without

requiring the maximum power on the PDCH. The reduced transmit power of the BTS helps

decrease the interference in the network and lower the power consumption of the BTS.




93

Benefits

This feature lowers the BTS transmit power without compromising the link quality. In this

way, the network interference and power consumption can be reduced, while the system

capacity can be increased.

Description

PS power control is classified into PS uplink open-loop power control, PS uplink closed-loop

power control, and PS downlink closed-loop power control. PS uplink open-loop power

control, supported by the feature GBFD-119115 Power Control, was introduced in GBSS8.0.

EGPRS downlink closed-loop power control was introduced in GBSS12.0. In GBSS14.0,

GPRS downlink closed-loop power control is introduced, and EGPRS downlink closed-loop

power control is enhanced.

When this feature is enabled, the MS measures the quality of each downlink radio block and

then reports the measured quality to the BSC through the PACKET DOWNLINK

ACK/NACK message. After processing the received information, the BSC performs the PS

downlink power control decision. If the BSC decides to perform power control, it calculates

the power attenuation value by using the PS downlink power control algorithm and then sends

the value to the BTS. Based on the received power attenuation value, the BTS adjusts the

transmit power on the current radio block.

This feature is suitable for a network with densely-scattered sites, high rate of frequency reuse,

and a large number of users. By controlling the transmit power on the PDCH in such a

network, the network interference and power consumption can be reduced, while the system

capacity can be increased.

Enhancement

GBSS14.0

1. GPRS downlink closed-loop power control is added.

2. EGPRS downlink closed-loop power control is enhanced and related algorithms are

optimized. In addition, the issue in GSBB12.0 where a coding scheme decreases due to

improper EGPRS downlink closed-loop power control is solved using the following

methods:

Power compensation is performed on measurement reports (MRs) during MR

preprocessing, and filtering is performed after power compensation, which minimizes the

impact of improper power control.

The impact of power control is considered during downlink link adaptation. This avoids

a sharp decrease in the coding scheme.

Dependency


None




The following feature cannot be concurrently enabled with this feature:




94


None

2.2.13 GBFD-119505 PDCH Dynamic Adjustment with Two Thresholds

Availability


Summary

With this feature, the conversion between PDCH and TCH can be dynamically performed

according to the traffic load in the cell. This feature ensures the speech quality of the cell,

reduces the possibility of CS services preempting the radio resources of PS services, and

effectively improves the channel utilization.

Benefits

This feature improves the CS access performance (indicated by the call setup success rate and

access delay) and PS retainability performance (indicated by the TBF call drop rate in uplink

and downlink).

Description

If the rate of idle channels in a cell is greater than the higher threshold for CS idle channel rate,

the CS traffic in the cell is light. In this case, idle TCHs can be dynamically converted into

PDCHs to improve the throughput of PS services. If the rate of idle channels in a cell is

smaller than the lower threshold for CS idle channel rate, the CS traffic in the cell is heavy. In

this case, PDCHs can be dynamically converted into TCHs to reduce the possibility of CS

services preempting the radio resources of PS services. If the rate of idle channels in a cell is

greater than the lower threshold for CS idle channel rate and at the same time smaller than the

higher threshold for CS idle channel rate, the CS traffic load and PS traffic load in the cell are

balanced. In this case, the dynamic conversion between PDCH and TCH does not need to be

performed. The higher threshold for CS idle channel rate and lower threshold for CS idle

channel rate are configured on the basis of the traffic load in the cell.

Enhancement

None

Dependency


None




None




95


None

2.2.14 GBFD-119506 GPRS/EGPRS Time slot multiplexing priority

Availability


Summary

When a GPRS user and an EGPRS user are multiplexed onto the same PDCH, the downlink

rate of the EGPRS user can be increased by adjusting the scheduling priority of the EGPRS

user to a level higher than that of the GPRS user. Based on the downlink rate increase, the

service experience of EGPRS users is improved, and the system throughput is increased.

Benefits

Operators can attract users to EGPRS services or GPRS services by adjusting the multiplexing

priorities of GPRS and EGPRS users on the PDCH, thereby increasing the downlink rate of

EGPRS users. Based on the downlink rate increase, the PS service experience of EGPRS

users is improved, and the system throughput is increased.

Description

By setting scheduling weight parameters related to EGPRS and GPRS users in a cell,

operators can adopt different uplink and downlink scheduling strategies for EGPRS users and

GPRS users, thereby improving the service experience of EGPRS users. When an EGPRS

user and a GPRS user are multiplexed onto the same PDCH, the radio block sent in downlink

to the EGPRS user must be in the GMSK modulation mode during the scheduling of the

uplink radio block of the GPRS user. This decreases the downlink rate of the EGPRS user. If

the scheduling priority of the GPRS user is lower than that of the EGPRS user, the number of

times that the downlink radio block of the EGPRS user uses the GMSK modulation mode is

decreased, because scheduling times of the uplink radio block of the GPRS user are less than

the scheduling times of the uplink radio block of the EGPRS user. In addition, the scheduling

times of the downlink radio block of the EGPRS user are more than the scheduling times of

the downlink radio block of the GPRS user. Therefore, the downlink rate of the EGPRS user

and the system throughput are increased.

Enhancement

None

Dependency


None






96


None


None

2.2.15 GBFD-119401 Extended Dynamic Allocation (EDA)

Availability


Summary

EDA helps assign more timeslots in the uplink to the MS, improving the uplink throughput.

Benefits

This feature improves the uplink rate and helps transmit large amount of data in the uplink. In

this way, the user satisfaction is improved.

Description

Generally, the GPRS/EGPRS downlink services outnumber the GPRS/EGPRS uplink services.

However, in some cases, a higher uplink bandwidth is required; for example, a large-sized

email is sent through the GPRS/EGPRS. The EDA feature enables a single MS to be assigned

with four timeslots in the uplink. If the MS high multislot classes feature is supported, the MS

with the high multislot class 34 can be assigned with five timeslots in the uplink, meeting the

high bandwidth requirements in the uplink.

EDA is based on the uplink dynamic allocation. The network assigns multiple timeslots in the

uplink to the MS. The MS listens to all the assigned PDCHs. When the MS hears the assigned

USF on the assigned PDCH, the MS uses the uplink block corresponding to this PDCH and

the uplink block corresponding to the assigned PDCH with a greater timeslot number. Once

the MS is able to send uplink blocks, it will not listen to the following assigned channels.

Therefore, the MS can use more uplink channels.

The uplink extended dynamic allocation requires the support from the MS. The MS will

indicate whether it supports GPRS uplink extended dynamic allocation and EGPRS uplink

extended dynamic allocation through the message containing the information about radio

access capability.

Enhancement

None

Dependency







97



None


MS should support.

2.2.16 GBFD-119402 MS High Multislot Classes

Availability


Summary

High multislot classes ensure that a maximum of five timeslots in the uplink or downlink are

assigned to a single MS, improving the uplink or downlink throughput of a single MS.

Benefits

The BSS supports the MS with a high multislot class of 30 to 34. A maximum of five

timeslots on the downlink can be assigned to an MS. If an MS is of the high multislot class 34,

a maximum of five timeslots in the uplink can be assigned to the MS. Therefore, compared

with four timeslots in the uplink or downlink, the throughput is increased by 25%.

Description

The BSS supports the MS with high multislot classes from 30 to 34. A maximum of five

timeslots on the downlink can be assigned to an MS. If an MS is of the high multislot class 34,

a maximum of five timeslots in the uplink can be assigned to the MS. For a GPRS MS, the

maximum data rate increases from 85 kbit/s to 107 kbit/s (the throughput at RLC in theory);

for an EGPRS MS, the maximum data rate increases from 236 kbit/s to 296 kbit/s (the

throughput at RLC in theory). The total number of timeslots on both the uplink and downlink

cannot exceed six. That is, if five timeslots on the downlink are assigned to the MS, then only

one timeslot in the uplink can be assigned to the MS. The following table lists the multislot

capacity of MSs with multislot classes 30 to 34:

High Multislot Class

Maximum Number of Downlink Timeslots

Maximum Number of Uplink Timeslots

Maximum Number of Timeslots

30 5 1 6

31 5 2 6

32 5 3 6

33 5 4 6

34 5 5 6




98

For an MS with high multislot classes 32 to 34, if more than two timeslots in the uplink are

assigned to the MS, EDA function must be enabled.

Enhancement

None

Dependency







GBFD-114101 GPRS

GBFD-114201 EGPRS

If more than two timeslots in the uplink are required, the GBFD-119401 EDA must be used.



2.2.17 GBFD-114151 DTM

Availability


Summary

Dual Transfer Mode (DTM) allows simultaneous transfer of CS service and PS service. That

is, a subscriber can send photos or browse websites during the call conversation. The 3G

network provides concurrent CS service and PS service. With DTM, the subscribers in a GSM

network can enjoy services similar to those provided in a 3G network. In addition, in areas

with insufficient 3G coverage, subscribers can use the services that are similar to 3G services

through the GSM network.

Benefits

DTM supports concurrent CS service and PS service. That is, a subscriber can provide PS

service without affecting the CS service.

With DTM, the concurrent CS services and PS services which are originally available only in

the 3G network are now available in the GSM network.

With the passage of time and development of technology, the data services are becoming the

new area of profit growth. The concurrent CS service and PS service becomes a new

requirement. Without DTM, only the class A mobile phone with complex hardware supports concurrent CS service and PS service. However, due to its complexity, few manufacturers




99

provide such mobile phones. The implementation of DTM is a foundation for the extensive

application of data service. With the interaction between the CS services and PS services and

the multimedia services provided by operators, the call duration is prolonged and a large

amount of data traffic is generated. This considerably increases the revenue of operators.

Description

DTM is a 3GPP-defined standard function. This feature implements the simplified operation

function of the class A mobile phone, that is, concurrent CS services and PS services. In DTM

mode, the CS resource (TCH) and PS resource (PDCH) are assigned to the MS

simultaneously. According to the multislot capacity of the MS, different number of channels

in the uplink or downlink can be assigned to the MS to meet the requirement for different

bandwidths. DTM supports MS with multislot class 5 and higher classes. According to the

MS multislot capacity, the BSC assigns two channels in the uplink or downlink to the MS:

one for CS services and the other for PS services. The MS multislot class 9 with DTM can be

assigned with one channel for CS service and two channels for PS service.

PS CS PS

CS PS

PS PS CS

PS CS

CS PS

CS PS

PS CS

PS CSCLASS 5

CLASS 9

Downlink

Uplink

Downlink

Uplink

After DTM is enabled, the BSC must support BSS paging coordination in packet transfer

mode if the Network Operation Mode II or III is configured in a cell.

For an MS supporting DTM, when the MS initiates a location update in CS mode, the CS

channels (FACCH or SDCCH) can be used for location update and no PDCH is required. In

this case, the channel resources in PS domain are saved.

In DTM mode, the MS can establish the PS connection only after the PS connection is

established. If an MS providing data service needs to switch to the DTM mode, the TBF must

be released first; then, the MS switches to CS mode and a TBF connection. After that, the MS

switches to DTM mode. The following figure shows the state transition in DTM mode:




100

Figure 2-1 State transition in DTM mode

Enhancement

None

Dependency








GBFD-116201 Network-Controlled Cell Reselection (NC2)


The MSC, SGSN, and MS must support this feature.

2.2.18 GBFD-119403 Class11 DTM

Availability





101

Summary

Based on the common DTM feature, Class 11 DTM doubles the bandwidth of the uplink PS

services of the MS. When an MS using Class11 DTM provides mainly uplink service, the

channel assignment of Speech + 1Downlink + 2Uplink is supported. That is, two uplink

PDCHs and one downlink PDCH are assigned to the MS.

Benefits

Based on common DTM, Class 11 DTM doubles the uplink rate. Theoretically, the uplink rate

of the EGPRS MS can reach 110 kbit/s. Class11 DTM provides the bandwidth to support

streaming services.

With the Class 11 DTM function, the uplink rate or downlink rate can be increased according

to requirement, improving the user experience. In addition, the increased data flow can also

increase the revenues of operators.

Description

In DTM mode, the MS supports both CS service and PS service simultaneously. Besides

supporting the channel combination of Class11 DTM and Class9 DTM, the MS using Class11

DTM can occupy two uplink PDCHs and one downlink PDCH used together with EDA.

When the MS provides mainly the uplink services, Class11 DTM meets the requirements of

the MS more effectively.

CSPS

PSPS CSCLASS 11

Downlink

Uplink

Enhancement

None

Dependency







GBFD-114151 DTM

GBFD-119401 EDA


DTM should be supported by the MSC and SGSN. Class11 DTM should be supported by the MS.




102

2.2.19 GBFD-119404 HMC DTM

Availability


Summary

Based on common DTM, HMC DTM improves the bandwidth of the uplink and downlink PS

services of the MS. The MS can occupy a maximum of three uplink and downlink PDCHs

respectively during a call. The following channel assignments are supported: Speech +

3Downlink + 1Uplink, Speech + 2Downlink + 2Uplink, and Speech + 1Downlink + 3Uplink.

Benefits

Based on common DTM, HMC DTM triples the uplink and downlink rates. This improves the

user experience and provides bandwidth to support streaming services. In addition, the

increased data flow can also increase the revenues of operators.

Description

The DTM multislot classes defined in 3GPP protocols are classes 5, 6, 9, 10, 11, 31,33, 36-38,

and 41–44. The classes higher than class 31 are called High Multislot classes DTM (HMC

DTM). The DTM multislot capacity is in direct proportion to the uplink/downlink rate. The

higher the DTM multislot class supported by the GBSS equipment, the higher the

uplink/downlink rate.

Huawei HMC DTM supports multislot classes 31,33. In other words, based on the multislot

capacity of MS, a maximum of five channels in the uplink or downlink can be assigned to the

MS. The maximum number of channels on both the uplink and downlink is six. Except one

TCH assigned to the speech in the uplink and downlink respectively, a maximum of three

PDCHs in the uplink or downlink can be assigned to the MS.

The following table lists the multislot capacity of MSs with multislot classes 31 to 33:

Multislot class Maximum number of slots

Rx Tx Sum

31 5 2 6

33 5 4 6




103

For an MS with multislot classes 32 and 33, if more than three channels in the uplink are

assigned to the MS, EDA must be enabled.

Enhancement

None

Dependency







GBFD-114101 DTM

GBFD-119401 EDA

GBFD-119402 MS High Multislot Classes


DTM should be supported by the MSC and SGSN. DTM HMC should be supported by the

MS.

2.2.20 GBFD-119405 14.4kbit/s Circuit Switched Data

Availability


Summary

The GBSS equipment supports the transfer of PS services on individual speech channels with

a high rate of 14.4 kbit/s.

Benefits

Compared with common CS-based PS services, this feature provides PS services with higher

bandwidth.

Description

Huawei GBSS system supports different types of bearer services specified by GSM

specifications. The GBSS provides lower-layer connections and transmits service data to the

upper layer instead of processing these services. Huawei GBSS system supports the transfer

of the PS services on individual speech channels and the CS-based PS services with a high

rate of 14.4 kbit/s.




104

Enhancement

None

Dependency


None




None


The MSC must support this feature.

2.2.21 GBFD-119406 High Speed Circuit Switched Data

Availability

This feature is introduced in GBSS14.0.

Summary

With this feature, the Huawei GBSS can transmit high speed circuit switched data (HSCSD)

services on up to four TCHs at a rate of up to 57.6 kbit/s.

Benefits

This feature increases the bandwidth for CSD services to support more service types and

improve user experience.

Description

The Huawei GBSS supports multislot binding technology, which binds a maximum of four

TCHs to form a channel group to carry HSCSD services. This increases data transmission

rates from 14.4 kbit/s to 57.6 kbit/s, improving user experience.

The following tables list the HSCSD service rates supported by the Huawei GBSS using

different channel coding modes.

HSCSD service rates using 9.6 kbit/s transparent channel coding mode

Table 2-1 9.6 kbit/s transparent channel coding mode

HSCSD Rate Binding Mode

9.6 kbit/s 1 x 9.6 kbit/s





105




HSCSD service rates using 14.4 kbit/s transparent channel coding mode

Table 2-2 14.4 kbit/s transparent channel coding mode






Table 2-3 HSCSD service rates using 12 kbit/s non-transparent channel coding mode12 kbit/s

non-transparent channel coding mode


12 kbit/s 1 x 12 kbit/s




Table 2-4 HSCSD service rates using 14.5 kbit/s non-transparent channel coding mode 14.5 kbit/s

non-transparent channel coding mode





58 kbit/s 4 x 14.5 kbit/s

Transparent HSCSD calls must satisfy the listed rate requirements. If contiguous idle TCHs

are insufficient in a cell due to congestion, these calls cannot be processed in the cell.

Rates for non-transparent HSCSD calls may change. If contiguous idle TCHs are insufficient

in a cell due to congestion, actual data transmission rates may be lower than the requested




106

rates. When the cell is idle, additional TCHs are allocated to non-transparent HSCSD calls to

satisfy the requested data rates.

MSs under the Huawei GBSS can initiate the addition or subtraction of TCHs during a

non-transparent HSCSD service process.

Dual-timeslot extended cells do not support HSCSD services. Transparent HSCSD services

cannot be handed over to a dual-timeslot extended cell. If non-transparent HSCSD services

are handed over to such a cell, they have to use a single timeslot.

Currently, no MS supports the 57.6 kbit/s HSCSD service, and therefore this service cannot be

tested.

Enhancement

None

Dependency


None





GBFD-117002 IBCA




2.2.22 GBFD-119407 Active TBF Allocation

Availability


Summary

Active TBF Allocation monitors temporary block flow (TBF) transmission in real time,

helping users learn about the transmission quality of TBFs and channels in a cell. This

provides guidelines for allocating PDCHs to TBFs and converting dynamic PDCHs. This

feature enables low-throughput services to preferentially use a tight frequency reuse pattern

and high-throughput services to preferentially use a loose frequency reuse pattern. In addition

to reducing the number of activated PDCHs and improving the efficiency for PDCHs to carry

TBFs, this feature improves the user experience with high-throughput services, reduces

interference to CS services and the proportion of HR channels to all channels, and improves

the mean opinion score (MOS) for CS services.




107

Benefits Avoids unnecessary capacity expansion and brings economic benefit because the number

of activated PDCHs is reduced by about 25%, and the efficiency for PDCHs to carry

TBFs is increased by about 20%.

Reduces interference from PDCHs to the network because the number of PDCHs is

reduced. The MOS for CS services is increased because the proportion of HR channels

to all channels is reduced by 10%, and the high quality indicator (HQI) is increased by

about 0.2%.

Allocates resources to PS services more efficiently and maintains a high data rate for PS

services while occupying fewer resources.

Description

This feature increases the number of TBFs carried over each PDCH without affecting the

network access and transmission performance. This increases the efficiency for PDCHs to

carry TBFs and reduces the number of activated PDCHs.

Only data transmission occupies transmission resources on the Um interface during a TBF

duration, but data transmission time accounts for only part of the life cycle of a TBF. For

low-throughput services, data transmission time accounts for a small part of the life cycle of a

TBF. This leads to a low efficiency for PDCHs to carry TBFs, which wastes channel

resources.

This feature provides the following functions:

Samples and measures TBF multiplexing rates

This feature monitors the TBF status in real time and quickly samples the TBF status. If a

TBF is in transfer mode, the BSC records the sampling value as 1. Otherwise, the BSC

records the sampling value as 0. In addition, the feature filters the sampling values to obtain

the filtered TBF multiplexing rates. When an MS accesses a cell or resources are reallocated,

this feature accumulates the filtered TBF multiplexing rates to obtain the TBF multiplexing

rate for each PDCH, which is then used for channel allocation.

Manages PDCHs based on the TBF multiplexing rate

This feature allocates or reallocates PDCHs and coverts dynamic PDCHs based on the

obtained TBF multiplexing rate. The procedures for allocating or reallocating PDCHs

and converting dynamic PDCHs remain unchanged.

This function applies to hot spots for PS services with the following characteristics:

− The throughput is about 3 kbit/s to 5 kbit/s per PDCH.

− Instant messaging (IM) services account for more than 40% of PS services, and the

traffic of IM services accounts for about 10% of the total traffic.

− The CS traffic is heavy during busy hours.

− The traffic carried on HR channels accounts for about 30% of the total traffic.

− The TCH congestion rate is about 1%.

In these hot spots, Active TBF Allocation brings the following gains:

The number of activated PDCHs is reduced by about 25%.

The efficiency for PDCHs to carry TBFs (data rate per PDCH at the RLC layer) is

expected to increase by about 25%.

The MOS is improved because the proportion of HR channels for CS services is reduced

by 10%, and the HQI for CS services is increased by 0.2%.




108

If this feature is enabled, ensure that the following items do not deteriorate:

Data rate per user at the logical link control (LLC) layer

Uplink or downlink TBF call drop rate for EGPRS or GPRS services

PS service throughput

Enhancement

None

Dependency


None




None


None

2.3 EDGE Evolution

2.3.1 GBFD-510801 MSRD

Availability


Summary

MSRD is the abbreviation for MS Station Receiver Diversity.

Benefits The receiver sensitivity of the MS is increased by about 3 dB and the downlink coverage

distance is increased.

In conjunction with the dual-antenna interference cancellation (DAIC) technology, the

MSRD feature improves the anti-interference capability of the downlink, expanding the

downlink traffic capacity.

Description

The MSRD feature improves the signal receiving capability of the MS. With the introduction

of the DAIC technology, the MS obtains enhanced channel diversity. In addition, the GMSK




109

modulation scheme has an equivalent anti-interference capability with the 8-PSK modulation

scheme. Therefore, the data rate of the MS is improved and increases system capacity.

Enhancement

None

Dependency






The MS performing GBFD-510802 Dual Carriers in Downlink cannot perform

GBFD-510801 MSRD.



2.3.2 GBFD-510802 Dual Carriers in Downlink

Availability


Summary

Dual Carriers in Downlink is a method of increasing the downlink data rate. By using the

second downlink carrier, the downlink data rate is doubled theoretically.

Benefits

The downlink data rate is greatly increased. In this way, the GSM network can provide

subscribers with data services similar to those provided in a 3G network.

Description

The basic idea of the Dual Carriers in Downlink feature is to increase the number of timeslots

used by the base station to transmit data to an MS in a radio block period. The MS data rate is

increased by increasing the number of reception timeslots. The two carriers must be on the

same frequency band.

Take an MS supporting EGPRS2-A as an example. In a radio block period, the MS can

receive the data on only one carrier and the maximum number of timeslots that can be

assigned is five. Assume that the highest-rate coding scheme DAS12 is used. Then, the data

rate on each timeslot is 98.4 kbit/s, and the maximum data rate of the MS is 98.4 x 5 = 492

kbit/s. With the introduction of the technology of Dual Carriers in Downlink, the MS can

receive the data on two carriers in one radio block period. Therefore, the maximum number of




110

timeslots is 10. Assume that the DAS12 is used. Then, the maximum data rate of the MS is

98.4 x 10 = 984 kbit/s.

Enhancement

None

Dependency






The MS performing GBFD-510801 MSRD cannot perform GBFD-510802 Dual Carriers in

Downlink.

This feature relies on the following features:

GBFD-114201 EGPRS



2.3.3 GBFD-510803 Uplink EGPRS2-A

Availability

This feature is available for beta use from GBSS9.0.

Summary

The higher uplink performance for GERAN evolution (HUGE) solution is divided into two

phases: EGPRS2-A and EGPRS2-B. The uplink EGPRS2-A is the first phase of the solution.

With 16QAM modulation, this feature increases the rate of PS services by up to 30% in the

uplink theoretically.

Benefits

The rate of PS services in the uplink is increased greatly. When four timeslots are used for

uplink data transmission, the theoretical rate of EGPRS is increased from 230 kbit/s to 300

kbit/s.

Description

One of the aims of the GSM/EDGE radio access network (GERAN) evolution is to increase

the uplink and downlink rate of PS services. For the 3GPP GERAN, the HUGE solution is

used to increase the data rate in the uplink. With the 16QAM modulation, the GSM/EGPRS

network supports higher uplink data rate.




111

The uplink EGPRS2-A is the first phase of HUGE. With this feature, the rate of PS services in

the uplink is almost increased by 30% in theory. When four timeslots are used for uplink data

transmission, the theoretical rate of EGPRS is increased from 230 kbit/s to 300 kbit/s.

The new coding schemes supported by EGPRS2-A are listed in the following table.

MCS Coding Scheme

UA

S-7

UA

S-8

UA

S-9

UA

S-1

0

UA

S-1

1

Modulation Scheme 16QAM

Family B Apad10 A B Apad10

Bit Rate (kbps/TS) 44.8 51.2 59.2 67.2 76.8

Number of RLC Data Blocks 2 2 2 3 3

Payload (octets) 2x56 2x64 2x74 3x56 3x64

This feature applies only to Abis interface IP networking scenarios, including Abis IP over

E1/T1/cSTM-1 and Abis IP over FE/GE. Does not apply to Abis interface TDM networking

scene, that is, Abis TDM over E1/T1/cSTM-1.

Due to less terminal support Uplink EGPRS2-A, this feature is provided for trial, does not

recommend for commercial use.

Enhancement

None

Dependency





112


This feature applies only to IP networking scenarios, the PEUa/POUc boards are needed as

Abis interface board, and the DPUc boards are needed in GMPS/GEPS subrack.





GBFD-118601 Abis over IP or

GBFD-118611 Abis IP over E1/T1 or

GBFD-118401 Abis Transmission Optimization



2.3.4 GBFD-510804 Downlink EGPRS2-A

Availability

This feature is available for beta use from GBSS9.0.

Summary

The reduced symbols duration/higher order modulation and Turbo codes (REDHOT) solution

is divided into two phases: downlink EGPRS2-A and downlink EGPRS2-B. The downlink

EGPRS2-A is the first phase of the solution. With 16QAM and 32QAM modulation, this

feature almost doubles the rate of PS services in the downlink theoretically.

Benefits

The rate of PS services on the downlink is almost doubled. When ten timeslots are used on the

downlink, the theoretical data rate of EGPRS is increased from 592 kbit/s to 984 kbit/s.

Description

One of the aims of the GSM/EDGE radio access network (GERAN) evolution is to increase

the uplink and downlink rate of PS services. For the 3GPP GERAN, the REDHOT solution is

used to increase the data rate on the downlink. With higher order modulation (16QAM and

32QAM), high symbol rate (1.2 times), and Turbo codes, the GSM/EGPRS network supports

higher downlink data rate.

The downlink EGPRS2-A is the first phase of REDHOT. With this feature, the rate of PS

services on the downlink is doubled in theory. When ten timeslots are used on the downlink,

the theoretical data rate of EGPRS is increased from 592 kbit/s to 984 kbit/s.




113

The new coding schemes supported by EGPRS2-A are listed in the following table.

MCS

Coding

Scheme D

AS

-5

DA

S-6

DA

S-7

DA

S-8

DA

S-9

DA

S-1

0

DA

S-1

1

DA

S-1

2

Modulation

Scheme

8PSK 16QA-M 32QAM

Family B Ap Bp B Ap Bp Ap Bp

Bit Rate

(kbps/TS)

22

.4

27.2 32.8 44.8 54.4 65.6 81.6 98.4

Number of

RLC Data

Blocks

1 2 2 3

Payload

(octets)

1x

56

1x6

8

1x82 2x56 2x68 2x82 3x68 3x82




Due to less terminal support Uplink EGPRS2-A, this feature is provided for trial, does not

recommend for commercial use.

Enhancement

None




114

Dependency














2.3.5 GBFD-510805 Latency Reduction

Availability


Summary

The Latency Reduction feature consists of two sub-features: Reduced Transmission Time

Interval (RTTI) and Fast Ack/Nack Report (FANR).

Benefits

This feature reduces the packet transmission latency and therefore improves the customer

satisfaction.

Description

Latency reduction is important to GERAN evolution. In GERAN, the conversational services,

such as VoIP and Gaming, require short service latency. For the VoIP service that meets

customer requirements, the end-to-end latency should not exceed 300 ms, and the Frame Error

Rate (FER) should not exceed 2%. If the latency is within the permissible range, data can be

retransmitted to meet the FER requirement, improving customer satisfaction. In addition,

short latency can improve the customer experience of interactive and streaming services.

Two technologies can be used to reduce latency: RTTI and FANR.

RTTI: One radio block is still transmitted over four bursts, whereas two timeslots are

combined. Each timeslot transmits radio blocks of 10 ms TTI. In this way, the four bursts are

transmitted on two consecutive TDMA frames.




115

With the introduction of RTTI, the transmission latency on the Um interface and the TTI in

the access network are reduced. The TTI is reduced from 130 ms (the basic TTI is 20 ms) to

60 ms (the RTTI is 10 ms), and the single retransmission latency is reduced from 185 ms

(Basic TTI) to 95 ms (the RTTI is 10 ms).

FANR: Although RTTI can reduce transmission latency, under the existing Ack/Nack

reporting policy, when an RLC data block is erroneous or missing, this problem is not

immediately reported to the sender and another RLC data block is not retransmitted. As a

result, latency is required for assembling RLC data blocks into an LLC PDU. Therefore, an

efficient Ack/Nack feedback policy helps reduce the LLC PDU reassembly latency. Huawei

BSC supports FANR and enables the immediate feedback of data errors and the

retransmission of RLC data blocks. In this way, the LLC PDU reassembly latency is

decreased and the signaling overhead is reduced.




Enhancement

None




116

Dependency













GBFD-114151 DTM


The BTS and MSs must support this feature.

GBSS14.0 Optional Feature Description Public

Huawei Proprietary and Confidential


Page 117 of 362

3 Smart MBB

3.1 Intelligent Channel

3.1.1 GBFD-511603 IM Service Efficiency Improvement

Availability


Summary

With this feature, the BSC provides the following functions to increase channel usage:

Identifies IM services from various PS services.

Allocates fewer channels to process IM services based on configuration policies.

Multiplexes IM services on a PDCH.

Shortens the delay for releasing downlink TBFs.

Reduces the priority for scheduling IM services.

Benefits

The efficiency for PDCHs to carry TBFs is increased by 50% to 100% for IM services.

Description

Traditional PDCH management is based on the MS multislot capability and the average

number of MSs using the services carried on a PDCH. To ensure that user experience is not

affected, the BSC allocates as many PDCHs as needed to an MS based on the MS multislot

capability. This is done because the BSC cannot predict the PS service throughput. If the

average number of MSs using the services carried on a PDCH exceeds a specified threshold,

the BSC triggers excessive dynamic PDCH conversions.

Currently, IM services account for a large portion of GSM services, but the TBF transmission

duration is short because of low throughput. As a result, procedures in which no data block is

transmitted, such as TBF establishment, delayed downlink TBF release, and TBF release,

account for a large part of a TBF life cycle. This wastes channel resources.

This feature is implemented as follows:




118

1. The BSC uses an NIUa board to identify PS services.

2. The BSC identifies IM services from various PS services.

3. The BSC supports the setting of the following parameters for IM services:

− Maximum Number of PDCHs for IM ARP 1



− IM ARP1 Scheduling Weight



− IM PDCH Multiplexing Weight

− IM Downlink TBF Release Delay

4. The BSC allocates radio resources to IM services during peak hours based on the

maximum number of configured PDCHs, priority weight, PDCH multiplexing weight,

and delay for releasing downlink TBFs.

Enhancement

None

Dependency


The NIUa board is required.




None


None

3.1.2 GBFD-511604 Web Browsing Service Efficiency Improvement

Availability


Summary

With this feature, the BSC provides the following functions to improve the user experience

with regard to web browsing services:

Identifies web browsing services from various PS services.

Allocates an appropriate number of channels to process web browsing services.

Sets an appropriate multiplexing weight.




119

Sets an appropriate delay for releasing downlink TBFs.

Increases the priority for scheduling web browsing services.

Benefits

The user experience is improved with regard to web browsing services.

Description







Currently, web browsing services account for a large portion of GSM services. Such services

have medium throughput and a high requirement for delay.



2. The BSC identifies web browsing services from various PS services.

3. The BSC supports the setting of the following parameters for web browsing services:

− Maximum Number of PDCHs for Web Browsing ARP 1



− Web Browsing ARP1 Scheduling Weight



− Web Browsing PDCH Multiplexing Weight

− Web Browsing Downlink TBF Release Delay

4. The BSC allocates radio resources to web browsing services during peak hours based on

the maximum number of configured PDCHs, priority weight, PDCH multiplexing

weight, and delay for releasing downlink TBFs.

Enhancement

None

Dependency






None




120


None

3.1.3 GBFD-511605 Email Service Efficiency Improvement

Availability


Summary

With this feature, the BSC provides the following functions to improve user experience with

regard to email services or to increase the efficiency for PDCHs to carry TBFs for email

services:

Identifies email services from various PS services.

Allocates an appropriate number of channels to process email services.

Sets an appropriate multiplexing weight.

Sets an appropriate delay for releasing downlink TBFs.

Increases the priority for scheduling email services.

Benefits


1. The user experience is improved with regard to email services.

2. The efficiency for PDCHs to carry TBFs for email services is increased.

Description







Currently, email services account for a certain portion of GSM services. Such services have

high throughput and a low requirement for delay.



2. The BSC identifies email services from various PS services.

3. The BSC supports the setting of the following parameters for email services:

− Maximum Number of PDCHs for Email ARP 1



− Email ARP1 Scheduling Weight






121

− Email PDCH Multiplexing Weight

− Email Downlink TBF Release Delay

4. The BSC allocates radio resources to email services during peak hours based on the



Enhancement

None

Dependency






None


None

3.1.4 GBFD-511606 Streaming Media Service Resource Balancing

Availability


Summary


Identifies streaming media services from various PS services.

Reduces the number of PDCHs allocated to streaming media services.

Multiplexes more streaming media services on a PDCH.


Reduces the priority for scheduling streaming media services.

Benefits

This feature improves user experience with regard to other GSM services.

Description







122




Currently, streaming media services account for a small portion of GSM services. Such

services have a large throughput and a high requirement for delay, but the spectral efficiency

of GSM networks is limited. Therefore, the streaming media services are not recommended

for GSM networks.



2. The BSC identifies streaming media services from various PS services.

3. The BSC supports the setting of the following parameters for streaming media services:

− Maximum Number of PDCHs for Streaming Media ARP1



− Streaming Media ARP1 Scheduling Weight



− Streaming Media PDCH Multiplexing Weight

− Streaming Media Downlink TBF Release Delay

4. The BSC allocates radio resources to streaming media services during peak hours based

on the maximum number of configured PDCHs, priority weight, PDCH multiplexing

weight, and delay for releasing downlink TBFs.

Enhancement

None

Dependency






None


None

3.1.5 GBFD-511607 P2P Resource Balancing

Availability





123

Summary


Identifies point to point (P2P) services from various PS services.

Reduces the number of PDCHs allocated to P2P services.

Multiplexes more P2P services on a PDCH.


Reduces the priority for scheduling P2P services.

Benefits

This feature improves user experience with regard to other GSM services.

Description







Currently, P2P services account for a small portion of GSM services. Such services have a

large throughput, but the spectral efficiency of GSM networks is limited. Therefore, the P2P

services are not recommended for GSM networks.



2. The BSC identifies P2P services from various PS services.

3. The BSC supports the setting of the following parameters for P2P services:

− Maximum Number of PDCHs for P2P ARP1



− P2P ARP1 Scheduling Weight



− P2P PDCH Multiplexing Weight

− P2P Downlink TBF Release Delay

4. The BSC allocates radio resources to P2P services during peak hours based on the



Enhancement

None

Dependency





124





None


None

3.2 Smartphone Solution

3.2.1 GBFD-511501 Multiple CCCHs

Availability


Summary

Based on configuration of BCCH TRX timeslot 0 as the BCCH physical channel, the Multiple

CCCHs feature supports also configuring timeslots 2, 4, and 6 as the BCCH physical channel.

This increases the CCCH capacity within a cell, which improves the paging and random

access capability of the cell.

Benefits

The Multiple CCCHs feature increases the number of CCCHs in a cell, improving the paging

and random access capability of the cell.

Description

In GSM networks, BCCH physical channels are divided into the following several types of

logical channels:

Downlink: FCCH, SCH, BCCH, PCH, AGCH, NCH

Uplink: RACH

Of these, the PCH, AGCH, NCH, and RACH are referred to as CCCHs.

One cell is normally configured with a single BCCH physical channel and the BCCH TRX

timeslot 0 is configured as the BCCH physical channel. This Multiple CCCHs feature

supports configuring timeslots 2, 4, and 6 of the BCCH TRX as the BCCH physical channel.

These BCCH physical channels do not include downlink FCCH, SCH, or NCH. They do

include the downlink BCCH, PCH, and AGCH as well as the uplink RACH. The contents sent

over timeslots 0, 2, 4, and 6 BCCH logical channels are identical; however, the PCH, AGCH,

and RACH channels are able to send different contents. Consequently, configuring multiple

BCCH physical channels increases the CCCH capacity.




125

The BSC broadcasts the configured number of CCCHs to the MS in system information type

3 messages. The MS determines which timeslot to monitor for call information based on its

own IMSI.

Because BCCH physical uplink channels are all RACH channels, configuration of multiple

CCCHs increases the number of RACH channels within the cell. As a result, the Multiple

CCCHs feature also increases the random access capability of the cell.

Enhancement

None

Dependency


None


None

Dependency on other GBSS functions

None


None

3.2.2 GBFD-511502 Layered Paging

Availability


Summary

For the first paging, the BSC sends paging messages to the last cell on which the MS camps

and to its neighboring cells. If the first paging fails, the BSC sends paging messages to the

areas specified by the SGSN for the second paging.

Benefits

This feature narrows down the paging areas for packet switched (PS) services. This helps

lighten the CCCH load of the GSM network.

Description

With the rapid development of PS services in recent years, PS paging messages have

accounted for an increasingly larger proportion of paging messages than circuit switched (CS)

paging messages. This leads to heavy traffic load on the CCCHs and reduces the success rate

of CS service admission.

PS paging messages are sent on the basis of routing areas (RAs). In live networks, however, users processing packet services do not cross a large area. In this case, paging resources are

wasted. To save paging resources, Huawei introduces the Layered Paging feature. This feature




126

enables the BSC to send paging messages to the last cell that an active PS MS camps on and

to its neighboring cells. The BSC initiates the second paging by RAs if the first paging fails.

PS paging does not affect the user experience even though they may be delayed for a certain

period.

Figure 3-1 Layered paging

Enhancement

None

Dependency


None


None


None


None

3.2.3 GBFD-511503 Dynamic Multiple CCCH

Availability


Summary

When the CCCH load is high, the TCHs on timeslot 2, 4, and 6 on the BCCH TRX are

dynamically converted to CCCHs to extend the Um interface capability and relieve the load

on CCCHs. When the CCCH load is low, the CCCHs on timeslot 2, 4, 6 are dynamically

converted to TCHs to increase the channel usage.




127

Benefits

This feature is different from the static multiple CCCH function because it solves the problem

of the increase in sudden pagings, which improves the manual O&M efficiency and increases

the channel usage.

Description

The paging success rate decreases greatly during holidays and due to emergencies. When the

static multiple CCCH function is enabled, it is difficult to determine the number of static

CCCHs to be configured. If the number of configured static CCCHs is small, the paging

success rate remains low. If the number of configured static CCCHs is large, some TCHs are

wasted.

After the Dynamic Multiple CCCH feature is enabled, the BTS calculates the CCCH load and

determines whether to increase or decrease the number of CCCHs based on a specified

threshold. Then the BTS requests the BSC to increase or decrease one CCCH at a time. After

the increase or decrease, the BSC delivers a system information message containing related

configuration data to an MS so that the MS listens to the timeslot carrying the allocated

CCCH.

Figure 3-2 Dynamic Multiple CCCH

CCCH TCH

CCCH

configuration

CCCH traffic increases

CCCH traffic decreases

Enhancement

None

Dependency


None




None




128


None

4 Green

4.1 Power Consumption Saving

4.1.1 GBFD-117601 HUAWEI III Power Control Algorithm

Availability


Summary

This feature enhances and optimizes the GBFD-110703 Enhanced Power Control Algorithm

feature in terms of the filtering algorithm, interpolation of the measurement report, power

control decision algorithm, and flexibility of threshold configuration.

Benefits


Improves the efficiency and accuracy of power control.

Reduces the intra-network interference and the power consumption of the MS and BTS.

Increases the network capacity.

Improves the network performance.

Description

Power control is an important method for radio link control. Based on the expected values set

for parameters and the MRs on the uplink/downlink receive level and receive quality sent by

the BTS, the BSC determines whether to adjust the transmit power of the MS and the BTS.

Power control on the radio link is aimed at reducing the transmit power while maintaining the

transmission quality.

The HUAWEI III Power Control Algorithm feature enhances and optimizes the

GBFD-110703 Enhanced Power Control Algorithm feature in terms of the filtering algorithm,




129

interpolation of the measurement report, power control decision algorithm, and flexibility of

threshold configuration.

Optimizing the filtering/interpolation of the MR

With this feature introduced, the incorrect MRs obtained at the initial stage of channel

access do not affect the power control algorithm and therefore the change in trend of the

transmit power of the MS can be predicted based on the MRs in a more timely and

correct manner.

Optimizing the decision algorithm

Based on the filtered receive level and receive quality, this algorithm considers the gain

of the radio channel from frequency hopping, improving the accuracy of decisions.

Setting the power control threshold according to the service type

This algorithm sets different power control thresholds for AMRFR services, AMRHR

services, FR services, and HR services to optimize the power control on the AMR.

Enhancement

GBSS8.1

Support implementing with "GBFD-110802 Pre-processing of Measurement Report."

Dependency


None







None

4.1.2 GBFD-117602 Active Power Control

Availability


Summary

With this feature, the uplink power and the downlink power are calculated immediately after

an MS successfully accesses the network or an intra-BSC handover is successfully performed.

Then, the network informs the MS of the calculation result of the uplink power. The BTS and

the MS transmit signals at proper power. Therefore, power control is performed immediately.




130

Benefits

Through the power control of both the BTS and the MS, the system interference is reduced

and the service quality is improved. In addition, as the power consumption of the BTS and

MS is reduced, energy is saved, and the service time of the MS is prolonged.

Description

With this feature, the uplink power and the downlink power are calculated immediately after

an MS successfully accesses the network or an intra-BSC handover is successfully performed.

Then, the network informs the MS of the calculation result of the uplink power. The BTS and

the MS transmit signals at proper power. Therefore, power control is performed immediately.

Active power control during MS access

When an MS accesses the network, the following power control procedures are

performed:

− Calculation of the path loss: According to 3GPP TS 45.005, the path loss of the MS is

obtained on the basis of the transmit power used by the MS when the MS accesses

the network, and the uplink signal strength measured by the BTS.

− Calculation of the transmit power: The transmit power of the MS and the BTS is

obtained on the basis of the path loss of the MS and the expected signal strength in

the uplink and downlink.

− Execution of power control: When the TCH request is successful or when the MS

accesses the network, power control is performed immediately. This enables the BTS

and the MS to immediately transmit signals at proper power.

Active power control during intra-BSC handover

During the intra-BSC handover, the path loss of the MS is obtained on the basis of the

BCCH signal strength of the target cell recorded by the source cell before the handover

and the transmit power of the BCCH TRX of the target cell.

The calculation of the transmit power and the execution of power control procedures are

the same as those of active power control during MS access.

Enhancement

None

Dependency


None







None




131

4.1.3 GBFD-118103 Network Support SAIC

Availability


Summary

The network side performs active power control for the MS supporting single antenna

interference cancellation (SAIC).

Benefits

In the GSM network, the MS can use only a single antenna because of the limitations in size

and cost. Therefore, the co-channel interference cannot be effectively suppressed and the

spectral efficiency of the GSM system is reduced. Some attributes of interference are known,

for example, channel modulation type and training sequence. Therefore, it is possible to

improve the anti-interference capability of the receiver. The anti-interference technology

called SAIC is defined in the 3GPP R6 protocol for the MS with a single antenna. SAIC can

enhance the anti-interference capability of the downlink, increasing the capacity of the GSM

system. With this feature, the network side performs active power control on the MS

supporting SAIC to reduce the interference of the entire network, expand the system capacity,

reduce the transmit power of the BTS, and save the power consumption.

Description

SAIC is an anti-interference technology for suppressing the co-channel interference and

adjacent-channel interference. The SAIC feature applies mainly to the MS with a single

antenna and is used to reduce the impact of the interference reception of downlink signals

through a signal processing technology. Compared with common mobile phones, the MS

supporting SAIC has stronger anti-interference capacity. The network can modify the power

control policy as required to reduce the transmit power of the BTSs, reducing the interference

in the entire network.

In downlink power control, the network checks whether the MS supports the SAIC. If the MS

supports the SAIC, the network decreases the upper downlink level threshold and the lower

downlink level threshold according to the Huawei III power control algorithm; the network

increases the UL Qual.Upper Threshold and UL Qual.Lower Threshold, according to the

Huawei II power control algorithm.

Enhancement

None

Dependency


None







132





4.1.4 GBFD-114801 Discontinuous Transmission (DTX)-Downlink

Availability


Summary

The Discontinuous Transmission (DTX)-Downlink feature can reduce the power consumption

of the BTS and the frequency interference on the Um interface.

Benefits


This feature reduces the power consumption of the BTS and intra-system interference.

From the perspective of the entire network, this feature reduces the frequency

interference, increasing the network capacity.

Description

DTX consists of Voice Activity Detection (VAD) and Silence Descriptor (SID). In addition,

the GBSS automatically generates the comfortable noise to ensure the continuity of services.

VAD

When the Transcoder & Rate Adaptation Unit (TRAU) detests through the VAD module

that the data received from the MSC contains no voice information, it clears the voice

flag bit in the encoded TRAU frame. After identifying the flag bit, the BTS disconnects

the downlink until the flag is reset.

SID

The noise coding procedure is the same as the voice signal coding procedure. The SID

frame also experiences the channel coding, interleaving, ciphering, and modulating and

then is turned into the field containing the noise messages and sent out in eight

continuous bursts.

Comfortable noise

When receiving the uplink frames, the TRAU also judges the SID flag. If the SID is set,

the MS is in the intermittent period. To make subscribers feel that the GSM provides

services continuously, the TRAU inserts comfortable noise in the uplink.

With this feature, the TRAU can reduce the power consumption of the BTS, frequency

interference on the Um interface. In downlink DTX mode, the GBSS equipment makes

subscribers feel that the communication is continuous by providing the MSs with comfortable

noise.




133

Enhancement

GBSS8.1

Configuring the DTX according to the voice coding: DTXs for different voice coding can be

configured separately. That is, you can enable the DTX for the FR (including FR, EFR, and

AMR) voice coding and the DTX for HR (including HR and AMR HR) voice coding

simultaneously, and you can also enable FR DTX or HR DTX separately. The flexible

configuration helps reduce the intra-network interference while maintaining the voice quality.

Dependency


None




None



4.1.5 GBFD-114803 Discontinuous Transmission (DTX)-Uplink

Availability


Summary

If the encoder of the MS detects through the VAD module that the received voice signal is

environment noise only, the MS periodically sends the SID, and then the TRAU restores the

comfortable noise accordingly.

Benefits


This feature greatly reduces the power consumption of the MS and prolongs the standby

time of the MS.

From the perspective of the entire network, this feature reduces the frequency

interference, increasing the network capacity.

Description

The uplink DTX can reduce the transmit power of the MS and the co-channel interference on

the Um interface.




134

DTX consists of VAD and SID. In addition, the GBSS automatically generates the

comfortable noise to ensure the continuity of services.

VAD

In uplink DTX mode, if the encoder of the MS detects through the VAD module that the

received signal is environment noise only, the MS periodically sends the SID. When

receiving the uplink frames, the TRAU also judges the SID flag. If the SID flag is set,

the MS is in intermittent period. In this case, the TRAU restores the comfortable noise

on the uplink to make subscribers feel that the communication is continuous.

SID

The noise coding procedure is the same as the voice signal coding procedure. The SID

frame also experiences the channel coding, interleaving, ciphering, and modulating and

then is turned into the field containing the noise messages and sent out in eight

continuous bursts.

Comfortable noise

When receiving the uplink frames, the TRAU also judges the SID flag. If the SID is set,

the MS is in the intermittent period. To make subscribers feel that the GSM provides

continuous services, the TRAU inserts comfortable noise on the uplink.

The uplink DTX can reduce the transmit power of the MS, the co-channel interference on the

Um interface and the power consumption of the MS, and prolong the call duration and

standby time of the MS. In uplink DTX mode, the GBSS equipment makes subscribers feel

that the communication is continuous by providing the MSs with comfortable noise.

Enhancement

GBSS8.1

Configuring the DTX independently according to the voice coding: DTXs for different voice

coding can be configured separately. That is, you can enable the DTX for the FR (including

FR, EFR, and AMR) voice coding and the DTX for HR (including HR and AMR HR) voice

coding simultaneously, and you can also enable FR DTX or HR DTX separately. The flexible

configuration helps reduce the intra-network interference while maintaining the voice quality.

Dependency


None




None






135

4.1.6 GBFD-111602 TRX Power Amplifier Intelligent Shutdown

Availability


Summary

In the existing network, the cells are not busy all the time. When some cells are idle, some

TRXs can meet the current traffic requirements. In this case, you can disable the idle TRXs to

reduce the BTS power consumption and the operational expenditure of operators.

Benefits

This feature helps reduce the BTS power consumption and therefore greatly reduces the

operational expenditure. The power consumption of TRXs constitutes a major part of the

power consumption of BTSs. In the existing network, however, the TRXs are not always

working. With this feature, the power amplifiers of some idle TRXs are shut down to reduce

the power consumption of the BTS and power costs of operators.

Description

The TRX Power Amplifier Intelligent Shutdown feature can be enabled in a specific period.

Idle TRXs can be shut down based on the prediction of traffic load and traffic volume to save

energy. Alternatively, the power amplifiers of the disabled TRXs can be switched on to ensure

that these TRXs are available for use at any time. Before shutting down a TRX, the BSC

initiates an intra-cell handover for the calls on the TRX and then instructs the BTS to shut

down the TRX when there is no call on the TRX. If some calls on the TRX cannot be handed

over to other TRXs, the BSC does not instruct the BTS to shut down the TRX.

Generally, the channel allocation optimization measure is used together with this feature. That

is, channels are allocated to some centralized TRXs during the channel allocation. The

channels on the BCCH TRX are preferentially allocated to reduce the channel usage on the

non-BCCH TRX, reducing the power consumption of the BTS. In addition, the BTS allocates

channels based on the priorities of TRXs. That is, the channels are preferentially allocated to

TRXs with high priorities. In this way, the BSC centralizes busy channels on a few TRXs so

that as many idle TRXs as possible can be shut down.

Enhancement

None

Dependency


None







136

This feature cannot be used with the following features:

GBFD-113701 Frequency Hopping (baseband hopping) when a frequency hopping group is

involved in baseband hopping

GBFD-113701 Frequency Hopping (RF hopping) when inter-module RF hopping is applied


GBFD-113703 Antenna Frequency Hopping(in only GBSS9.0 and former version)

GBFD-118106 Dynamic Power Sharing


None

4.1.7 GBFD-111603 TRX Power Amplifier Intelligent Shutdown on Timeslot Level

Availability


Summary

The power amplifier consumption constitutes a major part of the TRX power consumption,

which constitutes a major part of the BTS power consumption. The TRX Power Amplifier

Intelligent Shutdown on Timeslot Level feature reduces the static power consumption by

controlling the power amplifier on timeslot level to make the idle timeslots consume no

power.

Benefits

This feature helps reduce the power consumption of the BTS and therefore greatly reduces the

operational expenditure. The power amplifier consumption constitutes a major part of the

TRX power consumption, which constitutes a major part of the BTS power consumption. In

the existing network, however, not all the timeslots are always working. With this feature, the

power amplifiers consume no power when the timeslots are idle, greatly reducing the power

costs of operators.

Description

The power amplifier is an important device used for transmitting power to the antenna system.

The power consumption of the power amplifier consists of static power consumption and

dynamic power consumption. The linear-shaped power amplifier requires a constant offset

voltage to enable power transmission at any time even when it does not transmit power. The

power consumption corresponding to the fixed offset voltage is called static power

consumption. The dynamic power consumption, however, refers to the power consumption

produced only when the power amplifier is processing services. The dynamic power

consumption increases with the output power of the TRX. When the power amplifier does not

process services, the dynamic power consumption is zero. In the industry, the static power

amplifier can be shut down only when all the TRXs process no service. When the dynamic

power consumption is zero, the power amplifier is shut down. Therefore, the total power

consumption of the power amplifier is zero.




137

Enhancement

None

Dependency


None




None


None

4.1.8 GBFD-111604 Intelligent Combiner Bypass

Availability


Summary

With this feature, the original TRX with high output power is replaced by two TRXs with

lower output power to reduce the power consumption of BCCH TRX while maintaining the

network capacity in low traffic periods. Therefore, this feature saves power for the BTS.

Benefits

This feature helps reduce the BTS power consumption and therefore greatly reduces the

operational expenditure. The power consumption of TRXs constitutes a major part of the

power consumption of BTSs. In the existing network, however, the TRXs are not always

working. In low traffic periods, this feature can change the working status of TRXs to further

reduce the power consumption without interfering with the coverage and therefore bring

benefits to operators.

Description

The ICB applies to the DTRU only. The ICB can be enabled only when all the non-BCCH

carriers are idle, some channels on the BCCH carrier are idle in the cell, and the DTRU on the

BCCH applies the combination mode with physical connection. For example, the ICB can be

enabled in an S4 cell with single antenna, two DTRUs, and BCCH TRX in combination

mode.

For an S4 cell, the output power of TRXs should be 30 W for the coverage requirement. In

normal cases, the TRX transmits at a high power of 60 W. After the combination mode is

applied, the output power is 30 W, which still meets the coverage requirement. In the existing

network, the traffic is low in some periods. When the timeslots on the BCCH carrier are idle,

the output power of the BCCH TRX is reduced to 15 W and the PBT mode is applied to




138

ensure that the combined output power retains 30 W. In this way, the TRX power is reduced

from 60 W to 15 W while maintaining the network capacity. This greatly reduces the energy

consumption of the TRX and therefore reduces the power consumption of the BTS.

Enhancement

None

Dependency


None



The ICB can be enabled only when all the non-BCCH TRXs are idle and some channels on

the BCCH carrier are idle in the cell.

The ICB applies only to the DTRU in combination mode. This feature is supported by the

optimized DTRU, the DRRU, and the DRFU.

The ICB cannot be enabled on the static PDCHs or on the PDCHs converted from the

dynamic PDCHs (TCHs).

When the output power of the TRX is 60 W and the static power level is 0 or 1, the ICB helps

save the energy. When the output power of the TRX is 40 W and the static power level is 0,

the ICB helps save the energy.



GBFD-113701 Frequency Hopping (baseband hopping)

GBFD-113703 Antenna Frequency Hopping



GBFD-111611 TRX Working Voltage Adjustment


None

4.1.9 GBFD-111605 Active Backup Power Control

Availability





139

Summary

The Active Backup Power Control feature takes different measures to prolong the service

time of the BTS in case of mains power cut due to power off, snow disaster, and earthquake,

ensuring sufficient time for repairing the equipment and improving the network robustness.

Benefits

When the external power supply of the BTS is interrupted, this feature provides various

choices for operators to meet different requirements. For a configured BTS, the coverage

preferred strategy ensures sufficient coverage, the capacity preferred strategy ensures high

traffic capability, and the backup power time preferred strategy prolongs the service time and

provides diverse services. This greatly improves the service quality for operators.

Description

When the external power supply of the BTS is interrupted, a power-off alarm is generated on

the BTS. The BTS then uses the batteries to supply power. To save the backup power, the

BTS automatically shuts down some TRXs under the control of the timer and then gradually

reduces the TRX transmit power with a certain step until the BTS is powered off. When the

external power supply of the BTS recovers, the previously disabled TRXs are enabled and all

TRXs transmit at the normal power.

The Active Backup Power Control feature takes into account the coverage, capacity, and

backup power time. Therefore, three modes can be configured: coverage preferred, capacity

preferred, and backup power time preferred.

Coverage preferred: Shut down some TRXs and then gradually reduce the transmit

power of the remaining TRXs.

Capacity preferred: Gradually reduce the transmit power of all TRXs and then shut down

some TRXs.

Backup power time preferred: Shut down some TRXs and at the same time reduce the

transmit power of the remaining TRXs.

This feature reduces the coverage of a cell gradually and therefore the MSs at the edge of the

cell are gradually handed over to the neighboring cells. Therefore, this feature has no negative

impact on the network performance.

Enhancement

None

Dependency


None




None





140

Huawei power backup device is required, such as APM30.

4.1.10 GBFD-111606 Power Optimization Based on Channel Type

Availability


Summary

Huawei GBTS equipment supports two modulation modes: 8PSK and GMSK. The working

voltage of the power amplifier varies with the modulation modes. When the 8PSK modulation

mode is changed to GMSK, the Power Optimization Based on Channel Type feature

accordingly adjusts the working voltage of the power amplifier to reduce the power

consumption of the TRX.

Benefits

This feature adjusts the working voltage of the power amplifier based on the working mode of

MSs. The flexible adjustment of the working mode ensures that the BTS always works in

optimal state while maintaining the service quality. This minimizes the power consumption

and saves the power.

Description

The Power Optimization Based on Channel Type feature involves two functions: dynamic

voltage adjustment and dynamic PDCH voltage adjustment.

The dynamic voltage adjustment provides different working voltages for the power amplifier

based on the modulation mode. If all channels on the TRX are configured as TCHs, the TRX

works in GMSK mode and the BTS provides the TRX with the working voltage required in

GMSK mode. If some channels on the TRX are configured as dynamic or static PDCHs, the

TRX works in 8PSK mode and the BTS provides the TRX with the working voltage required

in 8PSK mode. In this way, the feature reduces the power consumption.

As the GPRS traffic increases, an increasing number of dynamic PDCHs are configured on

the TRX. When no data service is processed and a great number of speech services are

processed on a TRX, the dynamic PDCHs are converted into TCHs to provide speech services.

According to the dynamic voltage adjustment function, the 8PSK mode is adopted on the

TRX because the TRX is configured with dynamic PDCHs. In this way, the voltage is

adjusted to a very high value, increasing the power consumption. The dynamic PDCH voltage

adjustment function, however, can detect the channel status on the TRX. When all dynamic

PDCHs are converted into TCHs, the voltage adjustment function is enabled to provide the

working voltage required in GMSK mode. If the TCHs are converted back into PDCHs, the

working voltage required in 8PSK is applied again.

Enhancement

None

Dependency





141

None









GBFD-111611 TRX Working Voltage Adjustment


None

4.1.11 GBFD-111608 PSU Smart Control

Availability


Summary

The PSU Smart Control feature switches on the required PSUs and shuts down the redundant

PSUs based on the required power consumption of the BTS. This improves the efficiency of

the power system and prolongs the service time of the power system.

Benefits

When the load is not heavy, the power system works with low efficiency, reducing the service

time of the power conversion modules. This feature flexibly adjusts the power supply

capability as required by controlling the number of working PSUs in real time. This avoids

the case that the power conversion equipment works under light load and prolongs the

working time of the equipment, reducing the costs of operation and maintenance.

Description

In certain BTS application scenarios, when the external power supply cannot provide the

working voltage of –48 V DC required by the BTS, the BTS power system should be added to

perform the power conversion such as conversion from 220 V AC to –48 V DC. The power

system consists of the PMU and PSUs. The PMU is responsible for the management of the

PSUs and the communication between the PSUs and the BTS. The PSUs are responsible for

power conversion.

In Huawei system, the PSUs are configured in N+1 mode according to the possible maximum

power consumption of the BTS. Generally, the power consumption of the BTS is lower than

its possible maximum power consumption. Therefore, the PSUs are usually in light load state.

This results in low efficiency of power conversion and shortens the service time of PSUs.




142

The PSU Smart Control feature switches on the required PSUs and shuts down the redundant

PSUs based on the required power consumption of the BTS. This improves the efficiency of

the power system and prolongs the service time of the power system.

For MBTS scenario, because MBTS of GSM, UMTS and LTE are sharing one PMU, only

one license of GSM, UMTS and LTE is required for MBTS, but if the corresponding network

is down, this function will be deactivated for MBTS.

Enhancement

None

Dependency


None




None


None

4.1.12 GBFD-111609 Enhanced BCCH Power Consumption Optimization

Availability


Summary

The Enhanced BCCH Power Consumption feature reduces the power consumption of the

BTS by reducing the transmit power of the non-BCCH timeslots on the BCCH TRX.

Benefits

The overall power consumption of the BTS is a major concern for operators.


This feature reduces the overall power consumption of the BTS and therefore saves the

power cost of operators.

This feature reduces the intra-network interference by reducing the transmit power to

enable the tighter frequency reuse.




143

Description

When the non-BCCH timeslots on the BCCH TRX are idle, this feature supports the

configuration of the transmit power of these timeslots.

When the non-BCCH timeslots on the BCCH TRX are occupied, this feature supports the

power control on these timeslots. The power control range can be configured on the Local

Maintenance Terminal.

Enhancement

None

Dependency


None




None


This feature may affect the accuracy of measuring neighboring cells by the MS. Therefore, it

is recommended that this feature be enabled during low traffic hours at night.

4.1.13 GBFD-111610 Dynamic Cell Power Off

Availability


Summary

The Dynamic Cell Power Off feature is used generally in a 900 MHz/1800 MHz dual-band

network.

In a specified period, if the traffic is low and a 900 MHz cell can carry all the traffic in the

coverage area of an 1800 MHz cell, then the 1800 MHz cell can be powered off to reduce the

power consumption of the BTS.

Benefits

By powering off the idle network devices in low traffic hours, the consumption of resources

can be reduced. This also reduces the operational expenditure of the operators.

Description

The Dynamic Cell Power Off feature means that within a specified period, the cells in the 900

MHz/1800 MHz dual-band network are dynamically powered off on the basis of the network traffic load. 900 MHz cells refer to the cells working on the 900 MHz or 850 MHz frequency




144

band, and 1800 MHz cells refer to the cells working on the 1800 MHz or 1900 MHz

frequency band. If the coverage area of an 1800 MHz cell is within the coverage area of a 900

MHz cell and no blind zone exists, then the 900 MHz cell is referred to as the same-coverage

cell of the 1800 MHz cell. Only 1800 MHz cell with same-coverage cells can be powered off.

When a cell meets the condition of dynamic cell power-off, the BSC hands over the MSs with

ongoing services to other cells. After the same-coverage cell is powered off, the BSC

periodically detects the load in the cell. When the load in the cell is constantly higher than the

cell load threshold, the cell is powered on again.

Cells are powered off dynamically based on cell configurations. Because dynamic cell

power-off affects network capacity, cells should be powered off only in specified periods of

low traffic, such as 00:00 to 6:00 in the morning. Cells cannot be powered off in other periods

so that the traffic absorption requirement is met.

Cell_B

1800M

Cell_A

900M

Cell_B

closed

MS_B

MS_A

MS_B

MS_C

High Traffic Low Traffic

Cell_A

900M

Enhancement

None

Dependency


None





GBFD-114402 Enhanced Dual-band Network

It is mutually exclusive with the following features:

GBFD-118106 Dynamic Power Sharing (Dual PA power sharing)





145

None

4.1.14 GBFD-111611 TRX Working Voltage Adjustment

Availability


Summary

The TRX power consumption accounts for a large proportion of the BTS power consumption.

The working voltage of the TRX is a major factor that affects the TRX power consumption.

Hence, to lower the TRX power consumption, the TRX should work under a suitable voltage

to ensure an efficient output power.

Benefits

Reduction in the TRX power consumption plays a key role in saving energy in a BTS system

because the TRX power consumption accounts for a large proportion of the BTS power

consumption. When the function of "TRX Working Voltage Adjustment" is enabled, the

efficiency of the output power of the TRX can be maintained, which helps reduce the

investment in power made by network operators on the base station equipment.

Description

The working voltage of the TRX is always set to a high level to ensure the maximum output

power of the TRX. In actual application, however, the maximum output power of the TRX is

not always required. In this case, if the TRX still works under such a high voltage, extra

power is consumed because a lower working voltage can also provide the required output

power. To reduce the power consumption of the TRX, Huawei developed the function of

"TRX Working Voltage Adjustment" that enables the intelligent adjustment of the TRX

working voltage according to the output power. For example, in the DTRU that works under

different output powers of 40 W and 60 W, this function supports the intelligent adjustment.

In addition, this function supports the intelligent adjustment of the Power Amplifier (PA)

working voltage based on different power levels to reduce the TRX power consumption.

Enhancement

None

Dependency


None




None





146

None

4.1.15 GBFD-111612 Multi-Carrier Intelligent Voltage Regulation

Availability


Summary

With this feature, the working voltage of the power amplifier of the multi-transceiver module

can be timely adjusted on the basis of its output power. This improves the working efficiency

of the power amplifier and reduces the power consumption of the BTS.

Benefits

With the advanced design structure applied, the multi-transceiver RF module of the 3900

series base station provides the operators with the benefits such as simplified configuration,

small space, and easy capacity expansion. When this feature is enabled, the multi-transceiver

RF module of the 3900 series base station can properly configure the working status of the

power amplifier and reduce the operation expenditure for operators without affecting the

network coverage.

Description

The power consumption of the TRX is a major part of the power consumption of the BTS.

The power consumption of the TRX is related to factors such as the number of actually

working TRXs, the traffic volume, output power, and working mode.

All the carriers in the multi-transceiver module share one power amplifier. When many MSs

access the same carrier, the output power of the carrier varies with the distance between the

MS and the BTS. From the perspective of the total output power of the multi-transceiver

module, in most cases, the output power is lower than the maximum output power of the

power amplifier. The power amplifier works most efficiently when it transmits at the

maximum power. The reduction of the output power affects the efficiency to some extent. The

flexible adjustment of working voltage of the power amplifier helps improve the working

efficiency of the power amplifier.

This feature monitors the output power of all the carriers within the module. When the total

output power of the power amplifier reduces after the measurement for a period, this feature

adjusts the working voltage of the power amplifier to a smaller value according to the related

algorithm. In this way, the power amplifier works with great efficiency after the output power

reduces, reducing the power consumption of the TRX.

Enhancement

None

Dependency


None




147







None




Page 148 of 362

5 Topology&Transmission

5.1 Transmission Efficiency

5.1.1 GBFD-116701 16Kbit RSL and OML on Abis Interface

Availability


Summary

With this feature, each signaling link occupies only 16 kbit/s bandwidth at the physical layer,

saving the transmission resources on the Abis interface.

Benefits


When the capacity of the BTS is small, such as O1 or O2, this feature can minimize the

transmission resources required on the Abis interface.

The lease cost for the satellite transmission resources is very high. This feature can save

bandwidth, and therefore it can be used when satellite transmission is used.

Description

With this feature, the RSL or OML occupies 16 kbit/s sub-timeslots. In this case, the signaling

and service can be configured in a 64 kbit/s timeslot on the Abis interface, and the signaling

of different BTSs can coexist in the same 64 kbit/s timeslot.

Compared with the traditional 4:1 multiplexing technology, the 16 kbit/s LAPD signaling link

mode can reduce the timeslot fragments, reducing the rent in the network with expensive

transmission cost such as the satellite transmission networking.

The bandwidth of each signaling link is limited to 16 kbit/s. Therefore, for the cell with high

traffic volume, the call access failure or call drops may occur because of signaling link

congestion.




149

Enhancement

None

Dependency


None




None



GBFD-116601 Abis Bypass

GBFD-117801 Ring Topology


GBFD-118601 Abis over IP

GBFD-118611 Abis IP over E1/T1

5.1.2 GBFD-117301 Flex Abis

Availability


Summary

With this feature, the Abis transmission resources can be dynamically allocated to MSs.

Benefits

Flex Abis enables the sharing of the Abis interface transmission resources among different

BTSs, cells, and services, improving the resource utilization. Especially for BTSs of large

capacity with multiple cells, cascaded BTSs, and the cells configured with the EDGE, this

feature can greatly improve resource utilization.

Description

In the CS domain, the timeslot transmission on the Abis interface adopts the resource pool

mode. The Abis resource is allocated to a TRX only when the TRX is busy. This can improve

the utilization of Abis resources. In the PS domain, the transmission resources on the Abis

interface are allocated based on 16 kbit/s sub-timeslot. A main timeslot is allocated to the

PDCH, and then additional timeslots are allocated with the steps of 16 kbit/s based on the

required coding rate on the Um interface. Huawei adopts 16 kbit/s as the unit so that bandwidth usage is greatly improved and bandwidth is saved as much as possible.




150

The synchronization timeslot, signaling link timeslot, OML timeslot, and PS idle timeslot still

adopt the fixed Abis allocation mode. Other Abis timeslots adopt the Abis pool mode.

Huawei BSS equipment also supports the allocation of half-rate channels on the Abis

interface, which is triggered on the basis of the load of the Abis resources. Abis timeslots are

allocated at a minimum rate of 8 kbit/s. When the resource usage on the Um interface does

not reach the congestion threshold but the transmission resource utilization has reached the

congestion threshold, 8 kbit/s half-rate channels on the Abis interface are allocated to improve

the utilization of Abis resources.

Enhancement

None

Dependency


None





GBFD-116701 16Kbit RSL and OML on Abis Interface







This feature cannot be used together with DXX.

5.1.3 GBFD-117702 BTS Local Switch

Availability


Summary

BTS Local Switch enables the BSC to perform speech loopbacks for a call within the BTS

coverage if the calling and called MSs are under the same BTS or the same group of BTSs.




151

Benefits

BTS Local Switch saves transmission resources over the Abis, Ater (only in A over TDM

mode), or A (only in A over IP mode) interface. The actual transmission network determines

the interface over which transmission resources are saved.

In Abis over satellite mode, this feature reduces the delay for transmitting voice data and

improves user experience.

Description

BTS Local Switch consists of the following functions: intra-BTS local switching (single-site

local switching) and inter-BTS local switching (inter-site local switching).

Intra-BTS local switching refers to the local switching for the calling and called MSs that are

under the same BTS. Voice data for a call is looped back within a BTS without being

transmitted over the Abis interface.

When inter-BTS local switching is enabled in Abis over TDM mode, the BSC performs

speech loopbacks within a BTS group for the calling and called MSs under a group of BTSs

cascaded in chain or tree topology. When inter-BTS local switching is enabled in Abis over IP

mode, the BSC transmits voice data between two BTSs for the calling and called MSs under a

group of BTSs to which IP routes are reachable.

After a call is established, the BSC performs a local switching if it detects that the calling and

called MSs are located in the same BTS or in the coverage of a group of cascaded BTSs and

the requirements for the local switching are met.

Before performing the loopback for the local switching, if the speech coding schemes of the

two MSs are different, the BSC adjusts the two speech coding schemes to the same scheme by

enabling the two MSs to adopt the lowest speech coding capability. In this way, the speech

coding schemes and the speech coding rates of the two MSs are consistent.

Figure 5-1 shows the circuit usage after BTS Local Switch is enabled. The system performs

speech loopbacks for both the calling and called MSs on the BTS side, and then releases the

timeslots used on the Abis and Ater interfaces.

Figure 5-1 BTS Local Switch

Huawei BTS Local Switch can be started on the basis of the prefix number or the congestion

conditions of the Abis resources or started unconditionally. For the BTS with special numbers,

this feature is unavailable.

TC BSC BTS

1

BTS 3

A Abis Ater Um

MS b

MS a BTS 2

Transfer channel loop

Transfer channel released

Core Network




152

If the CN equipment is not provided by Huawei, the following functions are unavailable after

BTS Local Switch is enabled: lawful interception, MSC announcement, DTMF, fax during

voice, and independent charging of BTS Local Switch.

BTS Local Switch has an impact on the speech quality. The times of speech coding and

decoding are reduced, enhancing the speech quality. In satellite transmission mode, there is no

satellite transmission delay because the speech loopback is performed. Therefore, the speech

quality is greatly improved.

BTS Local Switch and BSC Local Switch can be enabled at the same time or independently.

Enhancement

GBSS13.0

AMR Rate Adaptation under BTS Local Switch

AMR rate adaptation can be used together with BTS Local Switch. Based on the AMR rate

set and protocol-specified preferred rate set of both the calling and called MSs under a BTS,

the BSC obtains a new rate adjustment threshold to select the best AMR coding scheme for

both the calling and called MSs under BTS Local Switch. If the calling MS occupies an AMR

TCHF and the called MS occupies an AMR TCHH, or vice versa, the MS that occupies AMR

TCHH is switched to an AMR TCHF, and then the BSC adjusts the AMR codec rate of both

MSs before BTS Local Switch is enabled.

Dependency


None



Lawful interception is supported by BTS Local Switch in Abis IP over FE mode only when a

UTRPc board is configured.


If the TDM transmission mode is used on the Abis interface, this feature depends on the

GBFD-117301 Flex Abis feature.

In Abis over IP mode, this feature depends on the GBFD-118601 Abis over IP and

GBFD-118611 Abis IP over E1/T1 features.

The following features are mutually exclusive:




GBFD-119301 Voice Fault Diagnosis







153


GBFD-115701 TFO



GBFD-115711 EVAD





5.1.4 GBFD-118401 Abis Transmission Optimization

Availability


Summary

The Abis Transmission Optimization feature detects and compresses the idle voice frames by

using VAD and then sends the compressed data packet on the HDLC transmission channels

for statistical multiplexing. This improves the E1/T1 bandwidth usage. With this feature, each

E1/T1 can support 24 or 18 TRXs under the following conditions. (The number of TRXs

supported by E1 and T1 are different because the bandwidth of an E1 is 2 Mbit/s and the

bandwidth of a T1 is 1.55 Mbit/s.)

Full-rate CS services (excluding the half-rate and PS services)

Voice activation factor of 0.5.

Cascaded BTSs not carried on a single E1.

Benefits

In the radio access network, the transmission cost accounts for 20% of the operators'

expenditure, of which the transmission cost over the Abis interface makes up a large portion.

Therefore, to effectively reduce the CAPEX and OPEX of the operators, it is necessary to

introduce a technology that saves transmission resources while protecting the current

investment.

This feature can save the transmission resources of the Abis interface. By adding the BSC

interface hardware and upgrading the BSC and BTS software, the operator can improve the

utilization of Abis resources by 30% to 40%.

Under certain conditions, one E1 can carry 24 TRXs.

Description

The Abis Transmission Optimization feature introduces the HDLC frame and HDLC channel

without changing the physical transmission mode. It statistically multiplexes the traffic data,

signaling data, and OM data on the HDLC channel to obtain a higher transmission gain

through voice frame compression and multiplexing.




154

Figure 5-2 Abis transmission optimization-enabled networking

Different from the TDM resources, the HDLC resources can be shared by multiple MSs.

Therefore, the QoS mechanism is introduced to add the admission control and congestion

management after this feature is enabled.

Admission control is a major measure taken to prevent congestion and is an important part of

the entire QoS mechanism. The system determines the bandwidth required for the access of

new services to prevent port or link congestion and to ensure the QoS of the entire system.

Congestion management alleviates the congestion by using the mechanism of lowering the

speech coding rate when transmission resources are congested, improving the processing

capability of the entire system.

Enhancement

GBSS8.1

The function of manually configuring the HDLC channel is introduced.

GBSS8.1

The enhanced QoS is introduced.

Dependency


The BSC should be configured with the PEUa/POUc. If the BM/TC is separated, the DPUc

should be configured in the subrack where the PEUa/POUc is located for processing the

HDLC frame.






155







None

5.1.5 GBFD-112013 Abis Congestion Trigger HR Distribution

Availability


Summary

The Abis Congestion Triggered HR Distribution feature provides the following strategies for

alleviating the Abis congestion: preferentially allocating the TCHH, dynamic TCHF-TCHH

conversion, and queuing/preemption. In this way, the system capacity and speech quality are

dynamically balanced.

Benefits


This feature saves the transmission resources of the Abis interface and reduces the

network deployment cost.

When the transmission resources on the Abis interface are congested, this feature

maintains the system capacity by degrading the speech quality. When the transmission

resources are not congested, the speech quality recovers and therefore the system

capacity and the speech quality are dynamically balanced.

Description

When the Abis Congestion Triggered HR Distribution feature is enabled, the system triggers

the HR allocation based on the congestion condition of transmission resources on the Abis

interface. In peak hours, the transmission resources on the Abis interface are congested before

these on the Um interface. Therefore, the original dynamic TCHF-TCHH

conversion/preferentially allocating the TCHH based on the load of the Um resources cannot

ensure the system capacity. This feature performs the dynamic TCHF-TCHH conversion,

preferential allocation of TCHH, and queuing/preemption to alleviate the congestion of Abis

resources and increase the system capacity.

Dynamic TCHF-TCHH conversion

When the transmission resources on the Abis interface are congested, the qualified calls,

calls initiated by non-VIP subscribers, calls with high speech quality, and calls with

allowed path loss, are handed over from TCHF to TCHH. This alleviates the congestion

of transmission resources on the Abis interface and increases the system capacity. When

the congestion of transmission resources on the Abis interface is eliminated, the qualified




156

calls in the cell are handed over from TCHH to TCHF to improve the speech quality of

calls.

Preferentially allocating the TCHH

When the transmission resources on the Abis interface are congested, the TCHHs are

preferentially allocated to the newly accessed calls to slow down the congestion.

Queuing/Preemption

Similar to the queuing/preemption mechanism for the Um interface, the

queuing/preemption is performed for calls that allow queuing/preemption on assignment

or incoming handover. This ensures that services can be provided for subscribers with

high priorities even if the transmission resources on the Abis interface are severely

congested.

If the TDM transmission is used on the Abis interface, preferentially allocating the TCHH

mechanism is applied to eliminate the Abis congestion triggered by the GBFD-117301 Flex

Abis feature.

If the HDLC transmission is used on the Abis interface, preferentially allocating the TCHH

mechanism and queuing/preemption mechanism are applied to eliminate the Abis congestion

triggered by the GBFD-118401 Abis Transmission Optimization feature.

If the IP transmission is used on the Abis interface, dynamic TCHF-TCHH conversion,

preferentially allocating the TCHH, and queuing/preemption mechanisms are applied to

eliminate the Abis congestion triggered by the GBFD-118601 Abis over IP feature.

This feature can be used with AMR HR and normal HR.

Enhancement

None

Dependency


None




This feature depends on one of the following features:






None




157

5.1.6 GBFD-116901 Flex Ater

Availability


Summary

When the Flex Ater feature is enabled, the Ater resources are allocated according to the

channel type during the call connection. If the TCHFs are allocated on the Um interface, the

16 kbit/s timeslots on the Ater interface are used. If the TCHHs are allocated on the Um

interface, the 8 kbit/s timeslots on the Ater interface are used.

Benefits

This feature effectively reduces the transmission investment on the Ater interface in remote

TC networking. When the half rate accounts for 30% in the system, the Flex Ater-enabled

network saves the Ater transmission resources by up to 15%, compared with the Flex

Ater-disabled network.

. .

.

. .

.

. .

.

X% HR/AMR HR

with Flex Ater

X% HR/AMR HR

withoutFlex Ater100% HR/AMR HR

with Flex Ater

X% * 50%

50%

16K TS

8K TS

Description

The Ater interface is an internal interface between the GMPS/GEPS and the GTCS in the

Huawei BSS equipment. With this feature, the Ater resources are classified into 16 kbit/s

timeslots and 8 kbit/s timeslots.




158

The Flex Ater feature allocates the Ater resources according to the channel type during the

call connection. If the TCHFs are allocated on the Um interface, the 16 kbit/s timeslots are

used. If the TCHHs are allocated on the Um interface, the 8 kbit/s timeslots are used.

Therefore, the Ater resources are fully utilized.

The user can determine the initial proportions of the 16 kbit/s timeslots and the 8 kbit/s

timeslots based on the traffic module. If either type of resources is insufficient, the BSC

dynamically adjusts the Ater resources. If the 16 kbit/s timeslots are insufficient, two

continuous 8 kbit/s timeslots are incorporated into one 16 kbit/s timeslot. Similarly, if the 8

kbit/s timeslots are insufficient, one 16 kbit/s timeslot is divided into two 8 kbit/s timeslots.

The adjustment process is recorded in the traffic statistics. In addition, the user can query

through the LMT the number of the 16 kbit/s and 8 kbit/s timeslots of a specific subrack and

the usage of these timeslots. Based on the query result, the user can determine whether the

initial proportions of 16 kbit/s and 8 kbit/s timeslots are proper or the Ater resources are

congested.

When this feature is enabled and the transmission resources on the Ater interface are

insufficient, the BSC preferentially allocates the half rate to alleviate the congestion,

increasing the system capacity.

Enhancement

None

Dependency


None




None


None

5.1.7 GBFD-117701 BSC Local Switch

Availability


Summary

BSC Local Switch enables the BSC to perform speech loopbacks for a call within the BSC if

the calling and called MSs are under the same BSC. This saves Ater transmission resources

and TC resources (only in A over TDM mode).




159

Benefits


In A over TDM mode, 5% to 40% transmission resources over the Ater interface can be

saved if a remote TC is configured.

If there is a large proportion of calls involved in local switching, costs on devices can be

reduced by decreasing the number of TC resources.

In A over IP mode, 5% to 40% transmission bandwidth over the A interface can be saved.

The transmission bandwidth saving proportion varies with the traffic model used on the live

network.

Description Overview of BSC Local Switch

With this feature, if the calling and called MSs are under the same BSC, the speech

signals on the Abis interface are looped back to the MS without traveling around the

NSS. As shown in the following figure, BSC Local Switch saves transmission resources

of segment C. Note that BSC Local Switch is performed on the BSC side without

involving the NEs on the NSS side and the speech signals are not routed to the MSC.

The transmission resources at the D and E segments of the MSC, however, are not

released.

In addition, in BSC Local Switch, the speech coding schemes of the calling and called

MSs are the same and no coding conversion is required. Therefore, the TC resources

involved in BSC Local Switch can be released, and the speech quality is improved.

Figure 5-3 BSC Local Switch




160

BSC Local Switch based on the Ater transmission congestion

BSC Local Switch involves the following modes:

− Unconditional BSC Local Switch

− BSC Local Switch based on the Ater transmission congestion

− BSC Local Switch based on the prefix number

With BSC Local Switch based on the Ater transmission congestion enabled, the BSC

determines whether to perform the local switching based on the congestion of the Ater

resources to alleviate the congestion.

Speech version adjustment

When enabling BSC Local Switch, ensure that the speech coding rates of the calling and

called MSs are the same. If different speech coding rates are used, the BSC adjusts

different rates to the same rate through a forced handover. If the adjustment fails because

the calling and called MSs have no intersection of speech coding, BSC Local Switch

should not be enabled.

Inter-MGW scenario

If the calling and called MSs are served by different MGWs, the MGWs convert the user

plane protocol format. This results in the loss of the BSC identification information carried by

the speech frame. Therefore, BSC Local Switch fails to be triggered. There are two

inter-MGW scenarios:

1. In MSC pool networking mode, the calling and called MSs are served by different MGWs.

2. If the roaming and local MSs in a conversation are served by different MSCs, the CN

regards that the two MSs are served by different MGWs even if the BSC is connected to only

one MGW. In this case, BSC Local Switch fails to be triggered.

Enhancement

GBSS8.0

The lawful interception should be supported by Huawei MSC.

GBSS8.1

The supplementary services such as CW/HOLD/MPTY/ECT are supported.

The announcement should be supported by Huawei MSC.

The independent charging of local switching should be supported by Huawei MSC. That is,

the operators can adopt flexible charging strategies.

GBSS13.0

AMR Rate Adaptation under BSC Local Switch

AMR rate adaptation can be used together with BSC Local Switch. Based on the AMR rate

set and protocol-specified preferred rate set of both the calling and called MSs under different

BTSs, the BSC obtains a new rate adjustment threshold to select the best AMR coding

scheme for both the calling and called MSs under BSC Local Switch. If the calling MS

occupies an AMR TCHF and the called MS occupies an AMR TCHH, or vice versa, the MS

that occupies AMR TCHH is switched to an AMR TCHF, and then the BSC adjusts the AMR

codec rate of both MSs before BSC Local Switch is enabled.

In addition, this release supports BSC Local Switch in A over IP or Ater over IP mode.

Support BSC Local Switch in Abis over IP mode




161

When MO and MT are both located under same BSC, the calling voice is being looped back

at Abis interface of BSC, without going through NSS side, directly through package switch to

the called side. By using Abis IP method, BSC Local Switch can save 10% to 20%

transmission resource in Ater interface, accordingly save operator’s OPEX.

Dependency


None




In Abis over TDM mode, BSC Local Switch in compliance is mutually exclusive with the

following features:








BSC Local Switch in Abis over IP mode can be used together with the following features:




None

5.1.8 GBFD-116902 Ater Compression Transmission

Availability


Summary

When TDM is applied over the Ater interface, the IP over PPP over STM-1 scheme can be

used to carry traffic data. With the application of VAD, Ater MUX, PPP MUX, and IP header

compression, the data transmitted over the Ater interface is compressed and the transmission

efficiency over the IP interface is increased.




162

Benefits

This feature helps save the lease cost of the transmission equipment over the Ater interface.

Compared with the traditional TDM transmission, the Ater compression transmission saves

30% of the transmission resources.

Description

The BSC interworks with the remote TC subrack through the Ater interface. To save the

transmission resources over the Ater interface, the TC subrack is usually placed in the telecom

equipment room with the NSS devices. That is, the BSC is in BM/TC separated mode. In this

case, the speech channel over the Ater interface requires only a bandwidth of 16 kbit/s

(full-rate) or 8 kbit/s (half-rate). Compared with the PCM speech channel of 64 kbit/s over the

A interface, 75% of the transmission resources is saved. The application of this feature further

saves 30% of the transmission resources over the Ater interface.

The Ater transmission compression is based on IP over PPP over STM-1, where the IP

packets of speech data are encapsulated using the PPP and then transmitted over the

channelized STM-1.

The key technologies of the Ater transmission compression are as follows:

ML-PPP/MC-PPP, which helps to improve the reliability and bandwidth usage

− ML-PPP: Multiple PPP links are combined to form one ML-PPP group to provide a

link with relatively high bandwidth. At the local end, a large IP packet is divided into

several small packets, which are then transmitted concurrently to the peer end over

the PPP links. On receiving the packets, the peer end reassembles the packets and

restores the original IP packet for further processing. In the ML-PPP, multiple

E1s/T1s are combined to provide load sharing for the IP transmission. Therefore, the

bandwidth usage is increased.

− MC-PPP: The priority scheme is introduced to the MC-PPP on the basis of the

ML-PPP to facilitate the timely transmission of the real-time data, thereby reducing

the transmission delay of the real-time data.

VAD, Ater MUX, PPP MUX, and IP header compression, which help to save the

bandwidth.

− VAD: With the coordination of the DTX over the Um interface, this feature can

implement the discontinuous transmission of the speech frames over the Ater link.

Under typical call condition (VAD = 0.5), the Ater transmission efficiency is doubled

compared with that in the traditional condition.

− Ater MUX: Multiple UDP packets are multiplexed onto one IP/UDP packet. On

receiving the IP/UDP packet, the peer end demultiplexes the IP/UDP packet to restore

the data. This scheme reduces the transmission resources consumed by the IP/UDP

header.

− PPP MUX: Multiple upper layer packets such as UDP packets are multiplexed onto

one PPP frame. The description field of one to two bytes is added to each multiplexed

upper layer packets. All multiplexed upper layer packets share the information such

as the PPP header and CRC. In this way, the transmission resources consumed by the

PPP header are reduced.

IP header compression: The packets in one UDP data flow have the same source IP address,

destination IP address, source port, and destination port. With the IP header compression, the

redundant information in the IP/UDP header of the UDP data flow is removed. Therefore, the

transmission efficiency is improved.




163

Enhancement

None

Dependency


Both the BSC and the TC subrack should be configured with the POUc for the transmission

over the Ater interface.

In Abis over TDM mode, the BM subrack of the BSC should be configured with the DPUc.





GBFD-116901 Flex Ater


None

5.1.9 GBFD-511201 2G/3G Co-Transmission by TDM Switching

Availability


Summary

The SDH/PDH transport network can be shared by the GSM traffic and UMTS traffic using

the TDM timeslot cross connection function.

Benefits

This feature allows operators to minimize the investments in transmission infrastructure,

especially during the UMTS deployment phase when the traffic load of the network is low.

With this feature, the UTRAN and GBSS can share the physical transmission media to

achieve the exchange of user data and control data.

Description

Huawei radio equipment provides the multiplexing of the GSM and UMTS data on the same

SDH network by using the TDM timeslot cross connection function. The GSM data flow

involves TDM frames and IP packets. When transmitting the IP packets, the BSC and the BTS

map the IP packets onto multiple E1 timeslots by using the Abis IP over E1/T1. The UMTS

data flow involves ATM packets and IP packets. The RNC and the NodeB map ATM packets

or IP packets onto multiple E1 timeslots by using the function of fractional ATM or fractional

IP to implement the data transmission. The following figure shows the co-transmission principles.




164

TDM SW

time slottime slottime slottime slot



SDH/PDH


TDM SW



GBSC

NodeB

GBTS

RNC

Co-transmission

time slot Idle timeslot time slottime slot 3G traffic 2G traffic

TDM SWTDM SW




SDH/PDH


TDM SW



GBSC

NodeB

GBTS

RNC

Co-transmission

time slot Idle timeslot time slottime slot 3G traffic 2G traffic

This feature supports the TDM-based co-transmission on the Abis interface. That is, the TDM

transmission timeslots on the Abis interface are shared by the 2G and 3G services. The

following figure shows the 2G/3G co-transmission by TDM switching on the Abis interface.

The 2G data is transmitted on some E1 timeslots and the 3G data is transmitted on the

remaining timeslots by using the fractional ATM or fractional IP technology. In this scheme,

the 2G equipment (BSC and BTS) implements the timeslot cross connection through the

transmission interface board.

The GBSS8.0 supports only the TDM-based co-transmission of the following data on the Abis

interface: TDM frames of 2G services and ATM packets or IP packets of 3G services.

Enhancement

GBSS9.0

The GBSS9.0 supports the Abis IP over E1/T1. The Abis IP over E1/T1 supports the

TDM-based co-transmission of the following data on the Abis interface: TDM frames or IP

packets of 2G services and ATM packets or IP packets of 3G services.

Dependency


None.



Dependency on other GBSS/RAN features

The dependency of this feature for the GSM services on other features is as follows:

If the BSC and the BTS use the IP over E1/T1 on the Abis interface, this feature depends on

GBFD-118611 Abis IP over E1/T1.

The dependency of this feature for the UMTS services on other features is as follows:




165

WRFD-05030101 ATM over E1T1 on Iub Interface or WRFD-050411 Fractional IP Function

on Iub Interface


None.

5.1.10 GBFD-115301 Local Multiple Signaling Points

Availability


Summary

With this feature, a physical node is logically classified into multiple signaling points. Each

signaling point can be independently connected to other signaling points.

Benefits

This feature breaks the capacity limitation of a single signaling point using the narrowband

signaling. In addition, this feature is compatible with the traditional signaling networking

mode while meeting the signaling bandwidth requirements of the high processing capacity of

the BSC. Therefore, the operators' investment is saved.

Description

With network expansion, development of new services, popularization of the short message

service and wireless intelligent network service, and increase in the traffic volume, the

signaling flow between different signaling points increases rapidly. According to the protocols

related to the SS7 signaling, a maximum of 16 signaling links are allowed between single

signaling points. If the 64 kbit/s signaling link is used, a maximum of 1 Mbit/s bandwidth can

be provided for a single signaling point in the entire system. This is far from the requirements

for the signaling link bandwidth when the BSC is in full configuration.

With this feature, a physical node is logically classified into multiple signaling points. Each

signaling point can be independently connected to other signaling points. If a physical node is

logically classified into N signaling points, the number of links between this physical node

and the remote signaling point is extended to N x 16 because the maximum number of

signaling links between the OSP and DSP is 16. This feature breaks the limitation of 16

signaling links of a single signaling point using the narrowband signaling and meets the

signaling link requirements for large capacity processing of the BSC.

In addition, the requirements for the signaling networking capability of the CN are reduced

because the high-speed signaling technology is not used. Therefore, the operators' investment

is saved.

This feature is used together with the High Speed Signaling feature to support more flexible

signaling networking mode.

Enhancement

GBSS7.0




166

This application enhancement supports the use of local multiple signaling points in the MSC

pool.

Dependency


None





GBFD-118602 A over IP or



None

5.2 IP Transmission

5.2.1 GBFD-118606 Clock Over IP

Availability


Summary

Clock over IP provides accurate clock synchronization for several BTSs in the GBSS IP

network. Compared with the GPS clock, Clock over IP is a cost-effective clock solution. The

transmission cost is high because the IP timing packets are sent continuously. Huawei GBSS

equipment supports the function of defining the interval for sending IP timing packets. It can

reduce the transmission bandwidth as long as the BTS clock synchronization is guaranteed.

Benefits

In the IP-based GSM network, Clock over IP provides clock synchronization to guarantee the

normal operation of the GSM system.

Compared with the GPS clock synchronization, Clock over IP significantly reduces the cost

of network deployment.

Description

Clock over IP is a cost-effective clock solution for BTS synchronization. It consists of the IP

clock server and the IP clock client. The IP clock server extracts reference clock source from a

clock device such as a GPS or BITS. Then, the IP clock server sends the clock

synchronization information to the BTS by sending timing packets. As the IP clock client, the




167

BTS performs the adaptation on the IP packets and obtains the clock synchronization

information.

Every IP timing packet occupies a certain bandwidth. Therefore, in the case of leased network

or satellite transmission resources, the continuous transmission of IP timing packets leads to

an increased CAPEX and may even affect the ongoing services during peak hours. The GBSS

allows operators to define the interval for sending IP timing packets. In such a case, the IP

timing packets are sent when the load of the network is light. The BTS clock provided by the

GBSS can maintain a precision of 0.05 ppm within 90 days. Therefore, the bandwidth can be

saved and the BTS clock can be synchronized by sending the IP timing packets regularly. The

application scenario of Clock over IP is shown in the following figure:

Enhancement

GBSS8.1

Enhanced Clock over IP is available, which is used for the flexible configuration of clock

synchronization mode.

GBSS9.0

Primary and secondary IP clock server supported by the BTS: The IP clock server can be

configured on the basis of BTSs. The configuration of primary and secondary IP clock servers

is supported. When the primary IP clock server becomes faulty, the path to extract the clock

signals is switched to the secondary IP clock server, enhancing the flexibility and reliability of

the IP clock networking.

Dependency





168

The BTS must support this feature.




None


An independent IP clock server device is required.

5.2.2 GBFD-118620 Clock over IP support 1588v2

Availability


Summary

With this feature, the networking with the clock server that complies with IEEE1588v2 is

supported. Therefore, a highly precise synchronization clock for the IP-based BTS is provided.

Compared with the GPS clock, this feature is a cost-effective clock solution.

Benefits


The networking is flexible because the IP-based BTS can be networked with the clock

server that complies with IEEE1588v2.

This feature is a cost-effective clock solution because the IP-based BTS can obtain the

clock from the IP network.

The IP-based BTS supports the configuration of the primary and secondary IP clock

servers, increasing the reliability of the clock system.

Description

In TDM networking mode, the BTS can extract the clock signals from the GPS, BITS, or E1

lines. The clock extraction in IP networking mode does not function properly. In all-IP

networking mode, the E1 line clock is not available. The GPS line clock is available in the

all-IP networking mode but the GPS reception devices, antenna, and feeder must be added,

which increases the expenditure. The BITS clock is available for only a few sites. With the

Clock over IP feature, the clock solution becomes cost-effective because the clock reference

can be obtained from the IP network.

The Clock over IP is implemented through the IP clock server and IP clock client. The IP

clock server generates a time stamp and sends the time stamp to the BTS that is configured as

the IP clock client. The BTS uses an adaptive method to remove the delay and restore the

clock.

Huawei GBSS supports two types of clock standards: Huawei proprietary clock standard and

IEEE1588v2. This feature complies with only IEEE1588v2. With this feature, Huawei BSS

can interconnect with the Huawei IP clock server and other clock servers that comply with IEEE1588v2.




169

The following figure shows the networking scenario of Clock over IP support 1588v2.

The IP clock server can be deployed as an independent entity in the network. The IP clock

client can be deployed in the BTS. No additional hardware is required. An IP clock server can

serve up to 512 BTSs.

In addition, the IP-based BTS supports the configuration of primary and secondary IP clock

servers. When the primary IP clock server becomes faulty, the path to extract the clock signals

is switched to the secondary IP clock server, enhancing the reliability of the clock system.

Enhancement

GBSS12.0

Frequency Synchronization Based on IEEE1588v2 over MAC:

The clock synchronization for the Ethernet can be achieved by using the IEEE1588v2

technology. From the GBSS9.0, IEEE1588v2 over UDP has been applied to the layer 3 of the

multi-service transport platform (MSTP) network. In the GBSS12.0, IEEE1588v2 over MAC

can be applied to the layer 2 of the MSTP network.

IEEE1588v2 over MAC is a technology based on which transmission equipment forwards

timestamps according to the MAC addresses instead of the IP addresses. To achieve clock

synchronization in the MSTP network, all the involved transmission equipment must support

IEEE1588v2 over MAC.

There are two types of synchronization based on IEEE1588v2 over MAC, frequency

synchronization and time synchronization. Only frequency synchronization is supported by

this feature.

GBSS14.0

G.8265.1

The IEEE1588 standards were initially applied to industrial automation for accurate time

synchronization. In the telecommunications industry, these standards were originally used in

distributed networks for clock synchronization. Now, these standards have been applied to wide area networks (WANs). The IEEE1588v2 standards, which were released in 2008,




170

proposed the concept of "profile". "profile" allows vendors to select features to apply to other

fields instead of only the industrial automation field. Now, the IEEE1588 standards allow

vendors to select an IEEE1588 feature subset ("profile") to implement clock synchronization.

As an extension of the concept of "profile", the ITU proposes G.8265.1, which defines

interconnection standards for different vendors. Currently, G.8265.1 defines the profile for

frequency synchronization in layer 3 unicast mode and allows the interconnection between

devices supporting IEEE1588 from different vendors. In this manner, a BTS supporting

G.8265.1 can be connected to a clock server supporting G.8265.1 from another vendor.

Dependency


None




None


This feature should be supported by the clock server that supports the IEEE1588v2

specifications.

5.2.3 GBFD-118202 Synchronous Ethernet

Availability


Summary

This feature provides a solution for clock synchronization in the all-IP network. The clock of

a synchronous Ethernet can be obtained and recovered from the physical layer of the Ethernet.

The solution provided by this feature is easy to deploy, as it does not require additional BSC

or BTS hardware.

Benefits

The synchronous Ethernet is a key to the solution for all-IP transmission. In addition, it is an

economical and convenient solution for clock synchronization in the all-IP network.

Description

The clock synchronization technology adopted by this feature is based on the physical layer of

the Ethernet. By using this technology, the clock signals can be retrieved from the data flow

of the Ethernet link. With this feature, the data is transmitted at the physical layer by adopting

the highly precise clock. The receive end can retrieve and recover the clock directly from the

data flow. In this way, the precision of the clock is ensured.




171

Another benefit of the feature is that it does not require additional BTS hardware to achieve

clock synchronization in the all-IP network.

Enhancement

None

Dependency


The IP interface board must be used on the Abis interface.


This feature applies to only the 3900 series base stations.

Dependency on other features



All relay devices in the transport network must support this feature.

5.2.4 GBFD-118601 Abis over IP

Availability


Summary

Abis over IP enables the IP networking over the Abis interface.

Benefits

This feature adapts to All IP development trend of future transport layer and protocol

development.




172

The Abis interface incorporates the features such as high bandwidth and low cost deployment,

and it does not have any restrictions on the BSC capacity.

The low IP network deployment cost, short construction period, and easy maintenance

effectively reduce the CAPEX and OPEX of operators.

A firewall ensures the security for the BTS.

Description

Abis over IP allows operators to deploy an IP network between the BSC and the BTS.

In addition, this feature provides FE and GE interfaces and supports the IPv4 protocol. The

BSC connects to the BTS through a LAN or WAN, depending on the location of the BSC and

the BTS.

Abis over IP supports active/standby mode and load sharing mode, and is reliable.

The GBSS adopts the following mechanisms to ensure end-to-end high QoS.

Physical bandwidth shaping

The burst flow in the network is controlled by the buffer and token bucket. If the

messages are transmitted at a very high speed, the messages are buffered and transmitted

at a uniform speed under the control of the token bucket.

Priority mapping

A definite rule is used to identify the messages for different services. Then, the messages

are classified and prioritized, and they are associated with the corresponding flow control

and resource assignment. According to the load on the current network, a specific flow

control action is taken.

Congestion management

Congestion occurs when the rate at which data arrives at the port is higher than the rate

at which data is sent from the port. In this case, the voice quality deteriorates and the

data transmission rate decreases. The traffic statistics of the interface board show that the

number of discarded packets increases. As a result, congestion results in the increase of

the packet transmission delay and delay variation. Furthermore, an excessively long

delay leads to packet retransmission. If congestion increases, a large number of network

resources are wasted and improper resource assignment may lead to system deadlock or

system breakdown. The problem of shortage of network resources can be solved by

increasing the network bandwidth. In addition, preventive mechanisms like tail drop and

weighted random early detection (WRED) must be applied to avoid the network

congestion. When congestion occurs, the priority queue (PQ) or weighted round robin

(WRR) of queue scheduling is used to solve the congestion problem.

IPsec Enhancement

GBSS8.1

New QoS mechanisms VLAN are introduced in GBSS8.1.

VLAN: Virtual local area network. Based on the switching LAN, the network management

software is used to establish an end-to-end logical network across different network segments

and different networks. This improves the network processing capability and service

management capability. The network logically isolates the data of different applications

during transmission. For example, the network allocates the O&M data transferred between

the BSC and the BTS, data transferred by signaling messages, and service data to different

VLANs. This improves the security of network transmission and simplifies the flow control




173

management for data transmission of different applications. In application, one or several

BTSs or BSCs in the same physical network can be allocated to a VLAN.

GBSS9.0

Static IP address supported by the BTS: This feature supports the configuration of items such

as the BTS IP address, BSC IP address, and routing on the site maintenance terminal.

Compared with the configuration of dynamic IP address for the GBSS, the configuration of

static IP address is more complicated, but does not require the configuration of DHCP relay.

GBSS9.0

The GBFD-118609 IP Fault detection based on BFD feature is introduced.

Huawei GBSS supports bidirectional forwarding detection (BFD) on the Abis, A, and Gb

interfaces. BFD is a method of detecting IP connection failures by periodically transmitting

BFD packets between two nodes. When BFD packets are not received within the period of

several detection intervals, the communication between the two nodes fails. In this case,

procedures such as port switchover or IP rerouting are triggered to prevent traffic loss. The

interval of BDF detection is about 100 ms, and therefore it can be used for telecom services

over IP.

The BFD involves two cases: one hop and multi-hop. For one hop, the two nodes of the BFD

are the BSC and a layer 3 device connecting to the BSC, such as the router, BTS, or MGW.

For multi-hop, the two nodes of the BFD are the BSC and its peer device, such as a BTS,

MGW, or SGSN.

The BFD is applicable in the following scenarios:

1. The BSC is connected to a peer device such as the BTS, MGW, or SGSN by using a router.

In this case, the BFD can be used to check whether the router is working properly.

The BFD is activated for detecting any faults in p1 and p2. If p1 is faulty, the BSC triggers an

IP rerouting procedure. The packet is then sent and received over p2.

2. The BSC is connected directly to the peer device such as the BTS, MGW, or SGSN. In this

case, the BFD can be used to check whether the peer device is working properly.

BTS/CN

R2

R3

R4

p1

p2

R1

BSC

BSC




174

The BFD is activated for detecting any faults in p1 and p2. If p1 is faulty, the BSC triggers an

IP rerouting procedure. The packet is then sent and received over p2.

GBSS14.0

The BTS built-in firewall function is introduced.

The BTS built-in firewall automatically takes effect after the feature GBFD-118601 Abis over

IP is enabled. The BTS built-in firewall filters out malicious data and prevents network

attacks to avoid a system breakdown when a large number of system resources are consumed

by network attacks.

The BTS built-in firewall provides the following functions:

Access Control List (ACL)-based packet filtering: The ACL module sets ACL policies to

filter out malicious data. The ACL policy supports sextuple filtering. Sextuple refers to

source IP address, source port, destination IP address, destination port, protocol, and

DSCP. You can also choose to configure only some of these filters. This feature supports

both whitelist-based and blacklist-based filtering.

Attack packet filtering: This filtering provides basic network protection. It can be

configured to prevent various types of attacks, such as ARP spoofing, flooding attack,

and malformed packet attack.

Dependency


Embedded PCU should be used. IP Interface board is needed in Abis interface:

FG2a/FG2c/GOUa/GOUc.









BTS/CN

p1

p2




175


MRFD-210206 Tree Topology

MRFD-210204 Chain Topology

GBFD-113729 Adaptive Transmission Link Blocking



The BSC and its peer device must support BFD.

5.2.5 GBFD-118611 Abis IP over E1/T1

Availability


Summary

When TDM is applied over the Abis interface, the IP over E1/T1 scheme can be used to carry

traffic and signaling data.

Benefits

In the IP over E1/T1 scheme, the IP packets can be carried on the TDM-based network. For

the operators that have the abundant TDM transmission resources, the IP over E1/T1 scheme

facilitates the evolution to an all-IP network and thereby protects the investment.

The use of ML-PPP/MC-PPP enhances the reliability of the Abis links and improves Abis link

bandwidth usage.

As many as 18 to 21 TRXs can be supported by each E1 with compression technologies such

as VAD and Abis MUX. Compared with the traditional TDM transmission, the Abis IP over

E1/T1 saves 30% of the transmission resources and saves the lease cost of the TDM

transmission resources.

Description

In IP over E1/T1, the IP packets of the signaling and traffic data are packed using the PPP and

then transmitted over the E1/T1. The BTS and the Abis interface board on the BSC are

responsible for processing the PPP/ML-PPP.

The IP over E1/T1 can be applied for the networking between the BTS and BSC. The BTS

uses the E1/T1, and the BSC uses the E1/T1, channelized STM-1, or FE/GE. The following

figure shows the networking modes supported by the Abis IP over E1/T1.




176

BSC

BTS

SDH

BTS

IP over E1 IP over E1(STM-1)

IP over E1

IP over FE/GE

IP over E1

BTS

In IP over E1/T1, the clock can be the same as that in TDM transmission mode. That is, the

clock is obtained by locking the clock of one node to the upper-level node over E1. In IP over

E1/T1, the clock over IP scheme can also be used.

The key technologies in IP over E1/T1 are as follows:


ML-PPP: Multiple PPP links are combined to form one ML-PPP group to provide a link with

relatively high bandwidth. At the local end, a large IP packet is divided into several small

packets, which are then transmitted concurrently to the peer end over the PPP links. On

receiving the packets, the peer end reassembles the packets and restores the original IP packet

for further processing. In the ML-PPP, multiple E1/T1s are combined to provide load sharing

for the IP transmission. Therefore, the bandwidth usage is increased.

MC-PPP: The priority scheme is introduced to the MC-PPP on the basis of the ML-PPP to

facilitate the timely transmission of the real-time data, thereby reducing the transmission

delay of the real-time data.

VAD and Abis MUX, which help to save the bandwidth

VAD: With the coordination of the DTX over the Um interface, this feature can implement the

discontinuous transmission of the speech frames over the Abis link. Under typical call

condition (VAD = 0.5), the Abis transmission efficiency is doubled compared with that in the

traditional condition.

Abis MUX: Multiple UDP packets are multiplexed onto one IP/UDP packet. On receiving the

IP/UDP packet, the peer end demultiplexes the IP/UDP packet to restore the data. Multiple

UDP packets share one IP/UDP packet header, and therefore the IP transmission efficiency is

improved. For details, see the description of GBFD-118604 Abis MUX.

Enhancement

None

Dependency


IP over E1/T1 board is needed in Abis interface: PEUa/POUc.





177











When the BSC uses the STM-1 or FE transmission, this feature requires the support from the

external transmission device.

5.2.6 GBFD-118604 Abis MUX

Availability


Summary

If Abis over IP is used without any compression or multiplexing technology, the utilization of

transmission resources is low. Compared with TDM, the transmission bandwidth cannot be

saved. Therefore, a compression or multiplexing technology for saving the bandwidth must be

used in IP transmission mode.

Abis MUX is used to save the bandwidth and multiplex the packets. The BSC and the BTS

serve as transmitting end and receiving end of each other. When Abis MUX is applied, the

transmitting end multiplexes the UDP packets that meet the multiplexing condition. Multiple

UDP packets are multiplexed into one IP/UDP header at the transmitting end and then

demultiplexed at the receiving end to reconstruct the original data in the IP/UDP packets.

Therefore, the transmission efficiency is improved and the bandwidth is saved.

Benefits

By multiplexing and demultiplexing the IP/UDP packet, Abis MUX reduces the overhead of

each IP packet, increases the efficiency of the IP transmission, and saves the bandwidth.

Without the application of Abis MUX, the efficiency in IP transmission is about 32%.

Whereas, after Abis MUX is enabled, 14 full-rate speech packets are multiplexed, and the

efficiency of IP transmission can reach 73%, which is increased by 40%.

Description

The speech payload in GSM is small. After the IP transmission is applied, the speech payload

that is carried in the IP/UDP packets is smaller than the IP/UDP header. Therefore, the

transmission efficiency of the speech is very low. With the multiplexing of the IP/UDP header,

the UDP packets that meet the multiplexing condition are multiplexed at the transmitting end,




178

and demultiplexed at the receiving end. In this way, several UDP/IP packets are multiplexed

in one UDP/IP packet; in addition, several speech packets share one IP/UDP header.

Therefore, the efficiency of link transmission is improved.

The principle of Abis MUX is shown as follows:

IP UDP

Speech

payload A

IP UDP

Speech payload

A+B

B efore

using A bis Mux

MAC

MAC

MAC

IP UDP Speech

payload B

After using

A bis Mux

Abis MUX requires the support from both the BTS and the BSC. That is, after the BSC/BTS

multiplexes UDP packets, the BSC/BTS at the peer end must be able to identify multiplexed

and non-multiplexed packets and then demultiplex packets to reconstruct the original data

according to the multiplexing protocol.

Enhancement

None

Dependency


IP or IP over E1/T1 board is needed in Abis interface:

FG2a/FG2c/GOUa/GOUc/PEUa/POUc.





GBFD-118601 Abis over IP or GBFD-118611 Abis IP over E1/T1


None

5.2.7 GBFD-118612 Abis IPHC

Availability





179

Summary

This feature, Abis IP Header Compression (IPHC), compresses the IP/UDP header of the

packets transmitted over the Abis interface to save the transmission resources.

Benefits This feature saves more than 30% of transmission resources occupied by typical voice

services.

This feature improves the transmission efficiency in a newly deployed network that

adopts IP over E1 transmission or in a network where TDM transmission is upgraded to

IP transmission. The transmission efficiency is improved notably especially when

high-BER transmission media, such as microwave, are used for data transmission.

Description

IPHC improves the transmission efficiency by removing redundant information from the

IP/UDP header of UDP data streams.

In IP over E1 mode, typical small packets in a standard Abis IP packet such as speech packets

occupy only 50-60% of payload. This leads to low transmission efficiency. This feature solves

the preceding problem by enabling the transmitting end to compress the IP/UDP header of

packets. The compressed packets will be parsed by the receiving end. After the compression,

one typical full-rate voice packet can be shortened from 74 bytes to 50 bytes, which saves

more than 30% of transmission resources.

Enhancement

None

Dependency


None


For details, see the GBSS14.0 Feature List.




180





The two ends where the Point-to-Point Protocol (PPP)/Multilink Protocol (MP) is terminated

must support IPHC.

5.2.8 GBFD-118602 A over IP

Availability


Summary

Huawei GBSS8.0 and GBSS8.1 implements A interface over IP in proprietary protocols. The

features include TC in MGW and IP transmission on the signaling plane and user plane.

Benefits

With the increasing use of IP transmission in the wireless core network, the compressed

speech coding scheme is used on the Nb interface, and the TDM transmission is still used on

the A interface. In this way, a call across MSCs needs to be coded and decoded four times.

Compared with coding and decoding in TDM transmission mode that occurs only twice, the

application of IP transmission in the CN increases the number of TCs required by the BSC

and the MGW in the network and deteriorates the voice quality. However, when A interface

over IP is applied, together with the IP transmission on CN and transcoder free operation

(TrFO), the originated call and terminated call do not need to be coded and decoded.

Therefore, the voice quality is improved and the number of TCs required by the BSC and the

MGW is reduced.

With the increase of the network equipment capacity and the number of nodes, MSC pool is

an acknowledged solution that meets the requirements of disaster recovery and backup. In

TDM transmission mode, the application of MSC pool over the A interface is difficult to be

implemented due to the complexity of the physical connection. The IP transmission, however,

effectively address this problem.

In addition, A interface over IP complies with the trend of all IP in the transmission network

and simplifies the network maintenance.

Description

The details of this feature are as follows:

TC in MGW

To improve the voice quality, the feature of TrFO is supported. The TCs located in the

BSS are removed from the existing GSM network and are placed in the MGW. Under the

control of the signaling plane, when the calling and called MSs use the same speech

versions or compatible AMR codec set, the MGW performs coding and decoding

without using TC. Therefore, TrFO is implemented and then the voice quality is

improved. However, if the calling and called MSs use different speech versions or




181

incompatible AMR codec set, the TC in the MGW is required to converse speech version

under the control of the MSC-S.

MSC-S

MGW

BSS

A/IP

Mc/IP

MSC-S

MGW

Mc/IP

Nb

Nc

A/IP A/IP

A/IP

e.g. AMR coded

IP based protocol

stack

e.g. AMR coded

IP based protocol

stack

BSS

= Transcoder or Transcoder-pair, typically not used in MS-to MS calls = Signalling

= User p lane

Voice over IP

The A interface on the user plane is placed between the BSC and the MGW and adopts

the standard RTP/UDP/IP protocol to carry user data. The A interface supports all the

following speech codec types in the existing BSS:

GSM_FR: RFC 3551 for GSM_FR.

GSM_HR: ETSI 101318 for GSM_HR.

GSM_EFR: RFC 3551 for EFR.

AMR: RFC 3267 for AMR.

The speech coding scheme on the A interface is the same as that on the Um interface

because there is no TC configured in the BSS. However, the speech codec types are

different.

MAC / PPP

IP

UDP

RTP

Payload

MAC / PPP

IP

UDP

RTP

Payload

BSC MGW

Signaling over IP

The BSC supports signaling over IP on the A interface in the M3UA/SCTP/IP protocol

stack. The BSC is directly connected to the MSC server through the MTP3 User

Adaptation Layer (M3UA), and the data on the signaling plane and user plane can be

transmitted through the MGW routes.




182

To meet the requirements of TrFO and IP transmission on the user plane, some signaling

messages at the BSSMAP is modified. At the same time, the intra-BSS switchover

procedure of speech versions is added.

The introduction of A the interface over IP has no impact on the DTAP message.

MAC / PPP

IP

SCTP

M3UA

SCCP

BSSMAP+

BSC MSS

MAC / PPP

IP

SCTP

M3UA

SCCP

BSSMAP+

Enhancement

GBSS9.0

A over IP complying with 3GPP specifications: The signaling plane and user plane comply

with the related specifications in 3GPP R8. The user plane complies with TS43.903 and the

signaling plane complies with TS48.008. The CSD coding complies with RFC4040 and

RFC2198. Theoretically, the GBSS is capable of working with the IP-based CN devices

(supplied by the competitor) that comply with 3GPP R8.

CSD service transmission redundancy in A over IP: Certain CSD services, such as the fax

service, are quite sensitive to data loss. The retransmission mechanism for such services is

usually insufficient at the application layer. Therefore, the packet loss on the IP transmission

network has great impact on such services, for example, the fax is interrupted. This feature

enables the same CSD service data block to be transmitted in different RTP frames in A over

IP, ensuring the completeness of the data and enhancing the user experience of the CSD

services in A over IP. The CSD service transmission redundancy in A over IP supports a

maximum of three levels of redundancy; that is, a maximum of two consecutive RTP frames

can be discarded. The CSD service bearer in A over IP complies with the RFC4040

specification. The CSD service transmission redundancy in A over IP complies with the

RFC2198 specification.




Huawei GBSS supports bidirectional forwarding detection (BFD) on the Abis interface, A

interface, and Gb interface. BFD is a method of detecting IP connection failures by

periodically transmitting BFD packets between two nodes. When BFD packets are not

received within the period of several detection intervals, the communication between the two

nodes fails. In this case, procedures such as port switchover or IP rerouting are triggered to

prevent traffic loss. The interval of BDF detection is about 100 ms, and therefore it can be

used for telecom services over IP. For details, see section 5.2.4 "GBFD-118601 Abis over IP."

Dependency





183

The interface board for A over IP must be configured: FG2a/FG2c/GOUa/GOUc.










GBFD-115701 TFO



GBFD-115711 EVAD


GBFD-115702 TrFO


The MSC/MGW must support this feature.

The GBSS 8.0 and GBSS8.1 are only applicable to Huawei MSC/MGW.


5.2.9 GBFD-118622 A IP over E1/T1

Availability


Summary

When the SDH transmission is applied between the GBSS and CN equipment, the traffic and

signaling data can be carried by the PPP-based IP transmission over the A interface. The port

of the BSC can be E1, T1, or STM-1.

Benefits

With the IP over E1/T1 scheme, the IP packets can be carried on the TDM-based network. For

the operators that have the TDM transmission resources, the IP over E1/T1 scheme facilitates

the evolution to an all-IP network and thereby protects the investment.

The utilization of ML-PPP/MC-PPP enhances the reliability of the A interface links and

improves the bandwidth usage of A interface links.




184

The technique of UDP multiplexing over the A interface increases the IP transmission

efficiency. Compared with the traditional TDM transmission, the A IP over E1/T1 saves 30%

of the transmission resources and saves the lease cost of the TDM transmission resources.

Description

In IP over E1/T1, the IP packets of the signaling and traffic data are packed using the PPP and

then transmitted over the E1/T1/CSTM-1. The peer entity and the A interface board on the

BSC are responsible for processing the PPP/ML-PPP.

This feature enables the networking between the BSC and CN to use IP over PPP over

E1/T1/CSTM-1. The BSC adopts the E1/T1 or channelized STM-1 ports. The router at the

peer end or CN can adopt the E1/T1, channelized STM-1, or FE/GE ports. The following

figure shows the networking modes supported by the A IP over E1/T1.

MSCMGW

BSC

SD

H

MGW

IP over FE/GE

MGW

IP over E1/T1/CSTM-1 IP over FE/GE

MSC

IP over FE/GE

MSC

IP over FE/GE

IP over

E1/T1/CSTM-

1

IP over

E1/T1/CSTM-

1

IP over

E1/T1/CSTM-1

ROUTER

In IP over E1/T1, the clock can be the same as that in TDM transmission mode. That is, the

clock is obtained by locking the clock of one node to the upper-level node over E1.

The key technologies in IP over E1/T1 are as follows:


ML-PPP: Multiple PPP links are combined to form one ML-PPP group to provide a link with

relatively high bandwidth. At the local end, a large IP packet is divided into several small

packets, which are then transmitted concurrently to the peer end over the PPP links. On

receiving the packets, the peer end reassembles the packets and restores the original IP packet

for further processing. In the ML-PPP, multiple E1/T1s are combined to provide load sharing

for the IP transmission. Therefore, the bandwidth usage is increased.

MC-PPP: The priority scheme is introduced to the MC-PPP on the basis of the ML-PPP to

facilitate the timely transmission of the real-time data, thereby reducing the transmission

delay of the real-time data.

UDP multiplexing on the A interface, which help to save the bandwidth

UDP multiplexing on the A interface: After A over IP is introduced, the RTP/UDP/IP

packaging is applied to the data of the user plane, bringing down the transmission efficiency.

In this technique, however, multiple RTP packets are multiplexed onto one UDP packet. As a

result, the proportion of the packet header to the total packet decreases, and therefore the A

interface transmission efficiency is increased. For details, see GBFD-118610 UDP MUX for A Transmission.




185

Enhancement

None

Dependency


IP over E1/T1 Interface board is needed in A interface: PEUa/POUc.

To be specific, when the A interface uses the E1/T1 ports, the PEUa should be configured.

When the A interface uses the STM-1 ports, the POUc should be configured.

With this feature, the TC processing unit is no longer required on the BSC. The TC processing

unit is integrated into the MGW.










GBFD-115701 TFO

GBFD-113525 DTMF Downlink Message Filter


This feature should be supported by the CN and transmission equipment that support IP over

PPP.

5.2.10 GBFD-118610 UDP MUX for A Transmission

Availability


Summary

In A over IP, the RTP/UDP/IP packaging is applied to the data of the user plane, reducing the

transmission efficiency. When this feature is enabled, however, multiple RTP packets are

multiplexed onto one UDP packet. As a result, the proportion of the packet header to the total

packet decreases, and therefore the A interface transmission efficiency is increased.




186

Benefits

The UDP multiplexing improves the usage of the transmission resources on the A interface,

protects the investment, and reduces the O&M cost. The transmission efficiency can be

increased by 30% to 40% depending on the number of packets that are multiplexed.

Description

In A over IP, the RTP/UDP/IP packaging is applied to the packets of the user plane, bringing

down the transmission efficiency, particularly in the case of short packets of CS data.

This feature can solve the problem by adding a UDP multiplexing subheader which is smaller

than UDP and multiplexing multiple RTP packets onto one UDP packet. As a result, the

proportion of the packet header to the total packet decreases, and therefore the A interface

transmission efficiency is increased. The transmission efficiency can be increased by 30% to

40% depending on the number of packets that are multiplexed.

The UDP multiplexing is applicable regardless of whether the RTP header is compressed. The

UDP multiplexing is independent of the physical bearer. That is, the UDP multiplexing is

applicable to IP over E1/T1, IP over channelized STM-1 (CPOS), or IP over FE/GE.

Enhancement

None

Dependency


IP or IP over E1/T1 board is needed in A interface: FG2a/FG2c/GOUa/GOUc/PEUa/POUc.





GBFD-118602 A over IP or GBFD-118622 A IP over E1/T1



5.2.11 GBFD-118623 TDM/IP Dual Transmission over A Interface

Availability


Summary

This feature enables TDM transport and IP transport to be used simultaneously over the A

interface on the BSC side. Telecom operators can set a proper traffic proportion so that some




187

calls use TDM bearer and other calls use IP bearer. This feature is applicable to the scenario

where GSM is upgraded from the TDM network to the IP network.

Benefits

When GSM is upgraded from the TDM network to the IP network, telecom operators can

reconstruct the transport network gradually to ensure smooth migration.

Description

As specified by 3GPP GERAN Releases 7 and 8, the IP-based transport protocols for the

signaling and user planes are introduced into the A interface, and A over IP officially becomes

the network reconstruction trend. When GSM is upgraded from the TDM network to the IP

network, the BSC and the CN (including the MSC server and MGW) need to support TDM

transport and IP transport simultaneously on the A interface in a specified period. The purpose

is to ensure the smooth migration of the transport network.

The following stages are involved in the migration from TDM to IP on the A interface:

1) All-TDM stage: All the calls use TDM bearer during this stage.

2) TDM and IP dual-stack transport stage: Traffic is distributed to TDM transport and IP

transport according to the preset proportion during this stage. For example, 80% of the new

calls are established on TDM and 20% of the new calls are established on IP.

3) All-IP stage: All the calls use IP bearer and the original TDM bearer can be removed during

this stage.

The following figure shows the topology where TDM and IP dual-stack transport is applied to

the A interface. The BSC in the A-interface dual-stack transport state must support the

TDM-based PCM voice and IP-based compressed voice simultaneously. When TDM

transport is applied to the A interface, the TC in the BSS is used. When IP transport is applied

to the A interface, the TC in the MGW is used.

BSS

MSC-S MSC-S

MGW MGW

BSS

A/TDM

A/IP

A/IP A/IP

A/IP

A/TDM

A/TDMA/TDM

Nc

Nb

Mc/IP Mc/IP

Signaling

User plane

Transcoder

Transcoder or Transcoder pair




188

Enhancement

None

Dependency


The BSC must be configured with IP interface boards FG2a/FG2c/GOUa/GOUc for the A

interface.


None




The CN must support both IP and TDM.

5.2.12 GBFD-118603 Gb over IP

Availability


Summary

Gb over IP allows operators to deploy an IP network instead of using frame relay (FR)

between the BSC and the SGSN. Therefore, operators can fully utilize the advantages of IP

transmission so as to save the transmission cost and carry different types of services.

Benefits

This feature can reduce the cost of network investment. The IP transmission simplifies

network maintenance, saving the operation cost and maintenance expense.

The application of IP transmission increases the bandwidth over the Gb interface. Therefore,

the Gb interface does not restrict the bit rate of subscribers.

This feature facilitates the SGSN pool function. Compared with the frame relay mode, the

cost of using SGSN pool function in IP transmission is much lower because the SGSN pool

function requires a large number of links on the Gb interface. Therefore, SGSN pool can be

implemented in a more cost-efficient way.

Description

Gb over IP complies with the 3GPP protocol.

When Gb over IP is enabled, SGSN pool can be implemented after the license of SGSN pool

is obtained and no upgrade is required in the existing hardware.




189

Gb over IP supports dynamic configuration and highly automatic upgrade compared with the

frame relay mode. If SGSN pool is enabled, the application of Gb over IP can reduce the

configuration work for the Gb interface.

The Gb interface supports the FE/GE interface, the interface in active/standby mode or load

sharing mode, and the interconnection between the CN and the LAN or MAN.

The Gb interface supports IP services based on the DiffServ mechanism and guarantees the

QoS of the services with different levels. When the IP network is congested, the data packets

of the service with higher priority are preferably transmitted.

The BSC supports two kinds of end-to-end communications from the BSC to the SGSN, that

is, the FR network and IP network. In addition, two protocol stacks can work simultaneously

to minimize the impact of the IP transmission on the existing services.

When Gb over IP is applied, the transmission equipment supporting IP transmission should be

used. Compared with the FR equipment, the cost is lower.

With the increase of packet data services, the requirement for the bandwidth over the Gb

interface is higher. Gb over IP can compress the IP header and enable the data over the Gb

interface to share the bandwidth, improving the transmission efficiency and reducing the

transmission cost.

This feature does not support VLAN or multiplexing method.

Enhancement

GBSS9.0



Huawei GBSS supports bidirectional forwarding detection (BFD) on the Abis interface, A

interface, and Gb interface. BFD is a method of detecting IP connection failures by

periodically transmitting BFD packets between two nodes. When BFD packets are not

received within the period of several detection intervals, the communication between the two

nodes fails. In this case, procedures such as port switchover or IP rerouting are triggered to

prevent traffic loss. The interval of BDF detection is about 100 ms, and therefore it can be

used for telecom services over IP. For details, see section 5.2.4 "GBFD-118601 Abis over IP."

Dependency


The interface board for Gb over IP must be configured: FG2a/FG2c/GOUc.





GBFD-114101 GPRS


The SGSN must support this feature.




190


5.2.13 GBFD-118605 IP QoS

Availability


Summary

IP QoS provides a series of QoS mechanisms for the IP transmission to ensure the

transmission quality. The QoS mechanisms include admission control, congestion

management, port traffic shaping, queue scheduling, DSCP, and VLAN.

Benefits

IP QoS ensures the KPIs in the wireless network and prevents the drop in QoS caused by the

network congestion.

IP QoS meets different requirements of applications and enhances user experience.

Description

After the IP transmission is applied to the GBSS, the transmission resources are multiplexed

instead of being occupied exclusively. When the transmission resources are not sufficient, the

congestion may cause the increase of delay, packet loss, and call drop. Therefore, the QoS

mechanisms are required to guarantee the transmission quality of IP network. Huawei GBSS

equipment provides different QoS mechanisms at each protocol layer to guarantee an

end-to-end QoS, as listed in the following table:

Protocol Layer QoS Mechanism

Application layer 1. Admission control

2. Congestion management based on the congestion status of

transmission resources

3. Logical port shaping

4. IP PATH

IP layer 1. Priority mapping

Data link layer 1. VLAN

2. BFD detection

3. Congestion management (PQ, WRR, tail drop, WRED)

Physical layer 1. Physical bandwidth shaping

QoS mechanism at physical layer

Physical bandwidth shaping: The burst flow in the network is controlled by the buffer

and token bucket. If the messages are transmitted at a very high speed, the messages are

buffered and transmitted at a uniform speed under the control of the token bucket.




191

QoS mechanism at data link layer

VLAN: Virtual local area network (VLAN) logically isolates the data of different

applications during transmission. For example, the network allocates the O&M data

transferred between the BSC and the BTS, data transferred by signaling messages, and

service data to different VLANs. This improves the security of network transmission.

This function applies to Abis over IP and A over IP.

BFD detection: bidirectional forwarding detection (BFD) is a simple Hello protocol,

which is similar to the neighbor detection part of the routing protocols. Two systems

periodically send BFD check messages on the channel between the two systems. If one

system does not receive any check message from the other system for a long time, you

can infer that the channel is faulty. BFD detection enables the BSC to detect the link

fault between the BSC and the peer equipment in IP network quickly and then initiate

handover or active/standby switchover. Therefore, the link fault can be quickly identified

and isolated and therefore the service interruption time is greatly reduced. BFD is

applicable when IP transmission is established on Abis, A, and Gb interface.

Congestion management: The congestion occurs when the rate at which the data arrives

at the port is higher than the rate at which the data is sent from the port. Then, the voice

quality deteriorates and the data transmission rate reduces. In addition, the congestion

increases the packet transmission delay and delay variation. An excessively long delay

causes packet retransmission and further aggravates the network congestion. Therefore,

the congestion control mechanisms are used to prevent congestion for the packets

received, such as the tail drop and WRED. The queuing scheduling techniques such as

PQ and WRR are used to send the packets in real time based on the priority of each

packet. The congestion management is applicable when IP transmission is established on

Abis, A, and Gb interface.

IP layer

Priority mapping: A definite rule is used to identify the messages for different services.

Then, the messages are classified and prioritized, and they are associated with the

corresponding flow control and resource assignment. The QoS mapping in the

transmission network is implemented according to the data with different priorities.

Priority mapping is applicable to Abis over IP and A over IP.

Application layer

Admission control: Admission control is a major measure used to prevent congestion and

is an important mechanism of the entire QoS policy. The system determines the

bandwidth required for the access of new services to prevent port or link congestion and

to ensure the QoS of the entire system.

Congestion management: The admission control applies only to new services that

attempt to access the system; whereas, the congestion management applies to the

admitted services and alleviates the congestion when transmission resources are

congested. The BSC decreases the rates of the services that already access the network in

the congestion control and bandwidth reservation phases to increase the processing

capacity of the entire system.

IP PATH is used for admission control and LDR is used for congestion control.

According to the congestion severity, the admission control is classified into three phases:

normal admission, congestion control, and bandwidth reservation. Different admission

strategies are applied in different phases.

Normal admission phase: The transmission resources are not congested and all services

are allowed to access the system.

Congestion control phase: The transmission resources are slightly congested and the

services after rate reduction are allowed to access the system. The rate control measures




192

consist of the PS coding control, CS AMR coding control, and preferential assignment of

TCHHs for CS services.

Bandwidth reservation phase: The transmission resources are severely congested. When

the bandwidth is available, intra-BSC handover, incoming BSC handover, and paging

response are admitted. New services with high priorities are allowed to wait in queue and

preempt transmission resources, whereas other types of services are rejected.

Admission control is performed on the basis of the bandwidth usage of the IP PATH.

When an IP path is configured on the logical port or resource group, two-level (IP PATH

and logical port/resource group) admission is performed.

Logical port shaping: Generally, one physical FE/GE port on the BSC can carry the

traffic of multiple BTSs. Traffic shaping on this physical port cannot be implemented on

these BTSs. When burst flow occurs on one BTS, the traffic processing of other BTSs

may be seriously affected. Therefore, the BSC performs two-level traffic shaping on the

logical ports on the BTSs in Abis over IP mode. In this way, the BSC accurately controls

the traffic flow on the BTSs according to the processing capacity of each BTS. This

prevents the prolonged delay of services and the increase of delay variation and packet

loss rate.

IP PATH: In Abis over IP mode, the IP paths of different bandwidths are configured

according to the service type. This guarantees the transmission resource for each service

type and prevents different service types from preempting the transmission resources.

The IP path is a logical link with virtual bandwidth and is carried on the physical link in

the IP transmission network. The IP PATH mechanism is mainly applicable to admission

control. That is, admission control is performed during the MS access phase according to

the service type and the bandwidth of the corresponding IP path. Therefore, the effect of

the services on each other can be reduced.

IP/Ethernet

Transport Network

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

logicalport

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

Priority Queues

AF4EF

PQ

+W

R

Rq

ueues

BE

FE port

IP Scheduler

2 level shaper

1 level shaper

Enhancement

None




193

Dependency


IP Interface board is needed in Abis/A/Gb interface: FG2a/FG2c/GOUa/GOUc







GBFD-118602 A over IP or

GBFD-118622 A IP over E1/T1 or

GBFD-118603 Gb over IP


None

5.2.14 GBFD-118630 Ethernet OAM

Availability


Summary

The GBSS supports two types of Ethernet OAM: point-to-point Ethernet O&M (802.3ah) and

end-to-end Ethernet O&M (802.1ag). The functions of Ethernet OAM consist of fault

detection, monitoring, verification, and identification. Through these functions, this feature

achieves reliability and high availability of Ethernet services.

Benefits

The Ethernet O&M helps the operator to manage user access in terms of detection,

monitoring, and rectification of Ethernet faults.

This feature achieves reliability and high availability of Ethernet services, enables the service

provider to provide economical and efficient advanced Ethernet services, and ensures that the

services have high quality and reliability that are required by telecommunications services.

This feature is implemented at the GBSS equipment, minimizing the impact of Ethernet

bandwidth fluctuation or faults on the GBSS.

Description

With the introduction of IP GSM, the Ethernet as a type of transport bearer is widely used. As

a Layer 2 protocol, Ethernet O&M can report the status of the network at the data link layer.

Therefore, the network is monitored and managed more effectively. The functions of Ethernet

OAM consist of fault detection, notification, verification, and identification. The faults




194

involve the hardware faults that can be detected by the physical layer, such as link failure, and

the software faults that cannot be detected by the physical layer, such as memory bridging

unit damage. Ethernet O&M plays a significant role in reducing CAPEX/OPEX and

complying with the Service Level Agreement (SLA).

The GBSS supports two types of Ethernet OAM: point-to-point Ethernet OAM (802.3ah) and

end-to-end Ethernet OAM (802.1ag).

1. Point-to-point Ethernet OAM

The point-to-point Ethernet OAM complies with IEEE 802.3ah. The point-to-point Ethernet

OAM concerns the OAM of the last mile rather than the specific services. The OAM

implements point-to-point maintenance of the Ethernet through mechanisms such as OAM

discovery, loopback, link monitoring, and fault detection.

2. End-to-end Ethernet OAM

The end-to-end Ethernet OAM complies with IEEE 802.1ag. Regarding the OAM domain as

a whole, the end-to-end Ethernet OAM establishes end-to-end detection to perform

maintenance of the Ethernet based on the services.

When the BSC detects Ethernet faults or degraded network performance through the Ethernet

OAM, the BSC, based on the practical configuration, can perform operations such as route

reselection, port switchover, and board switchover to ensure proper communication on the

Ethernet.

Enhancement

None

Dependency


IP Interface board is needed in Abis/A/Gb interface: FG2a/FG2c/GOUa/GOUc








195





The Ethernet OAM protocol should be supported by the interconnected transmission

equipment.

5.3 Satellite Transmission

5.3.1 GBFD-113901 Satellite Transmission over Abis Interface

Availability


Summary

Satellite communication features wide coverage, fine mobility, flexible link scheduling, and

good topography adaptability. With this feature, operators can deploy BTSs to provide radio

services in mountainous regions, outlying areas, isolated islands, and other areas that are

difficult to be reached through conventional transmission.

Benefits

With this feature, the operator can deploy BTSs in the areas that are difficult to be reached

through conventional transmission, solving the communication problem in those areas. This

feature can also be used for emergency communication.

Description

The Abis interface of ordinary GSM equipment does not support satellite transmission

because satellite transmission encounters problems such as delay, jitter, and bit error. This

feature takes these factors into account, makes improvements on the Abis signaling

processing, voice processing, and clock processing, and uses special satellite transmission

equipment, addressing the drawbacks of satellite transmission.

With this feature, the voice quality of the CS services can reach the normal level. However,

there is a certain delay in voice because there is a long transmission delay in satellite

transmission.

In the cell using satellite transmission, the EDGE services are supported.

Enhancement

None




196

Dependency


None




None


None

5.3.2 GBFD-113902 Satellite Transmission over A Interface

Availability


Summary


good topography adaptability. This feature enables the operator to deploy the BSS system to

provide radio services in the areas that are difficult to be reached through conventional

transmission.

Benefits


In the areas that are difficult to be reached through conventional transmission, hot spots

on special occasions, or emergency conditions, this feature enables the operator to

deploy the BSS system to provide radio services.

The satellite transmission resources over the A interface can be shared with other

interfaces.

Description

The conventional terrestrial transmission has the problems such as small coverage, poor

topography adaptability, and poor flexibility. With this feature, the operator can deploy the

BSS system in isolated islands or small areas to share the same CN resources with other BSS

systems.

Huawei also provides the A interface monitoring function. This enables the operator to

monitor the circuit usage over the A interface based on which the operator can extend the

circuit (or add the transmission links). Therefore, the cost of the satellite link usage is

effectively reduced.

Enhancement

None




197

Dependency


None




None


None

5.3.3 GBFD-113903 Satellite Transmission over Ater Interface

Availability


Summary


good topography adaptability. This feature enables the operator to deploy the BSS system to

provide radio services in the areas that are difficult to be reached through conventional

transmission.

Benefits


This feature enables the operator to deploy the BSS system to provide radio services in

special geographical areas or emergency conditions.

With this feature, the BSC signaling processing unit can be deployed on the BTS side

and the TRAU unit can be configured in the CN equipment room. Therefore, the

transmission cost is reduced because the Ater interface adopts the 4:1 multiplexing

mode.

The satellite transmission resources over the Ater interface can be shared with other

interfaces.

Description

This feature enables the operator to deploy the BSS system to provide radio services in the

areas that are difficult to be reached through conventional transmission.

With this feature, the TRAU can be configured in the CN equipment room. This enables the

circuit over the Ater interface between the BSC signaling processing unit and the TRAU to

use the 4:1 multiplexing mode. As a result, the bandwidth required by the A interface circuit is

greatly reduced and therefore the cost of using the A interface is reduced.

In addition, Huawei provides the Ater interface monitoring function. This enables the operator

to configure the bandwidth for satellite transmission over the Ater interface as required and




198

dynamically extend the circuit with the increase of the traffic volume. In this manner, the

circuit lease cost, the operation and maintenance cost is greatly reduced.

Enhancement

None

Dependency


None




None


None

5.3.4 GBFD-113905 Satellite Transmission over Gb Interface

Availability


Summary

With this feature, the operator can deploy the network to provide radio services in the areas

that are difficult to be reached through conventional transmission.

Benefits


This feature enables the operator to deploy the BSS system to provide PS services in

special geographical areas.

The satellite transmission resources over the Gb interface can be shared with other

interfaces.

Description

With this feature, the operator can deploy the network to provide radio services in the areas

that are difficult to be reached through conventional transmission.

Enhancement

None




199

Dependency


None




None


None

5.4 RAN Sharing

5.4.1 GBFD-118701 RAN Sharing

Availability


Summary

On the condition that independency of CNs of multiple operators is maintained, RAN Sharing

enables multiple operators to share one GBSS network so that they can use the resources

(including the BSC, BTS, antenna system, transmission, and so on) in the GBSS network

simultaneously.

Benefits

The GBSS equipment sharing enables new operators to access the network easily and

implement the network coverage quickly.

Operators can fully utilize the network resources and increase the revenue by sharing the

equipment on the existing network.

This feature reduces the comprehensive operation cost of operators.

Each operator carries out radio services independently so that they can maintain the

independence of business development from the network planning.

Description

RAN Sharing supports a maximum of four operators. Each operator has an independent CN

(MSC and SGSN). The shared GBSS uses a uniform network management system, which

implements comprehensive management of all the resources in the GBSS.

The shared services in the GBSS are CS services and PS services. For processing these

services, the GBSS routes them to the specific CN to which the cell belongs.




200

In addition, RAN Sharing supports the coexistence of shared resources and non-shared

resources in the BSS. For example, some resources in the BSS, such as all the resources under

one BTS belong to a specific operator. Therefore, other operators cannot use these resources.

The resources under other BTSs in the GBSS can be shared by multiple operators.

The network structure of RAN Sharing is shown as follows:

Enhancement

None

Dependency


None


Refer to the BTS Dependency of feature list.


None


The following M2000 feature must be activated:

WOFD-220200 RAN Sharing Management-GBSS

5.4.2 GBFD-118704 Abis Independent Transmission

Availability





201

Summary

In a RAN sharing network, multiple telecom operators share a base station and associated

auxiliary devices. Cells of different telecom operators can reside under one base station, but

each cell can only belong to one telecom operator. The transmission resources under the base

station can be shared among telecom operators or exclusively used by their respective telecom

operators.

Benefits

Telecom operators flexibly deploy transmission resources, which are applicable in different

scenarios.

Description

In a RAN sharing network, base station resources are usually shared among telecom operators

to reduce Capital Expenditure (CAPEX). Base station resources include site location, power

supply, antenna system, and transmission resources.

If telecom operators have their respective transport networks and transmission resources are

not shared, the Abis interface must support independent transmission.

Each telecom operator's signaling and traffic data is carried by their own transmission

resources over the Abis interface. Only the OM link provided by a specific telecom operator

is shared among telecom operators.

In Abis over TDM transmission mode, E1 ports are not shared among telecom operators.

In Abis over IP transmission mode, logical transmission resources are not shared among

telecom operators.

Enhancement

None

Dependency


None





GBFD-118701 RAN Sharing


None




202

5.4.3 GBFD-118702 MOCN Shared Cell

Availability


Summary

BSS Sharing enables multiple telecom operators to share BSS equipment on a per BTS basis

while still using their respective core network (CN) equipment. A cell, however, cannot be

shared among telecom operators. That is, cells of different operators can reside under one

base station, but each cell can only belong to one telecom operator.

MOCN Shared Cell enables multiple telecom operators to share the BSS equipment on a per

cell basis while still using their respective CN equipment. That is, all the resources under a

cell can work as a resource pool and be shared among telecom operators.

Benefits

The cell-based BSS equipment sharing not only drastically improves the sharing degree of

spectrum, BSS equipment, transmission bandwidth, and network management, but also

minimizes the CAPEX of the operator.

The efficient use of GSM spectrum resources lays a firm foundation for the development of

LTE.

Description

In existing GSM networks, multiple PLMN identifiers cannot be broadcast in a cell due to

protocol limitations, and a GSM MS cannot receive multiple PLMN identifiers. Therefore,

multiple telecom operators use a common PLMN identifier in a GSM cell. The BSC selects a

CN node to serve an MS depending on the setting of the MOCN Switch parameter, which

can be set to CNSEL(CN Select) or BSCSEL(BSC Select).

In a network with the MOCN Shared Cell feature enabled, both the roaming MSs and the

MSs subscribing to different telecom operators exist. The BSC identifies the IMSI, TMSI, or

P-TMSI to determine whether an MS is a subscribing MS or a roaming MS:

If the MS is a subscribing MS, the BSC routes the MS to the CN of the telecom operator

to which the MS subscribes.

If the MS is a roaming MS, the BSC routes this MS to a specific telecom operator

according to the specified rate of distributing roaming MSs among telecom operators.

When a telecom operator is specified for an MS, the CS-domain handover area, NC2 area,

and PS-domain handover area of the MS must belong to the area permitted by the telecom

operator. After this feature is enabled, the BSC integrates this feature with other handover

decisions (such as decisions based on coverage, quality, load, or priorities) to select a target

cell for a subscribing MS or a roaming MS. Then, the BSC triggers an intra-GSM or

GSM-to-UMTS CS-domain handover, NC2, or PS-domain handover.

Enhancement

None




203

Dependency


None





GBFD-117401 MSC Pool

GBFD-119701 SGSN Pool


If the MS routing is selected by the CN, the list of VLRs in which an MS is allowed to roam

needs to be configured at the HLR, or the list of LAIs in which an MS is allowed to roam

needs to be configured at the MSC server.

5.4.4 GBFD-118703 IMSI-Based Handover

Availability


Summary

To meet the operator's requirements of network planning and service, the network can be

divided into multiple areas, and an MS of a specific type can move only in the specified area

to obtain services. That is, the operator can restrict the service area of an MS by configuring

the mapping between the IMSI number ranges and the network areas.

Benefits

In RAN sharing mode, one BSC is shared by multiple operators, which may have different

partner operators. An MS can be handed over only between the networks of partner operators.

In non-RAN sharing mode, MSs are provided with differentiated services based on service

areas.

Description

The operator can divide a network into multiple areas called handover shared areas at the

BSC, based on location areas. In addition, the operator configures the mapping between the

IMSI number ranges and the handover shared areas to restrict the area in which an MS can be

handed over.

During an intra-BSC handover, the BSC determines the target cell to which an MS is to be

handed over according to the IMSI number range of the MS. In this case, the target cell must

belong to the handover shared area.

During an incoming inter-BSC or incoming inter-RAT handover, the BSC determines whether

to allow the MS to access the target cell according to the IMSI number range of the MS. If the




204

MS is not allowed to access the target cell, the handover request is rejected. That is, the MS

cannot be handed over to this BSC.

Enhancement

None

Dependency


None


None


None


The Common Id and Handover Request messages sent by the MSC are required to carry

IMSI.




Page 205 of 362

6 Site Solution

6.1 PICO Solution

6.1.1 GBFD-510601 PICO Automatic Configuration and Planning

Availability


Summary

The pico base station is BTS3900B. After being installed and powered on, the BTS3900B can

connect to the BSC automatically with the network automatic detection function. Operators

do not need to configure radio parameters for cells. The M2000 obtains radio parameters

based on frequency bands and scanning results of the uplink and downlink level of

surrounding frequencies reported from the BTS, and then performs the automatic

configuration and planning of the BTS39000B.

Benefits This feature helps operators to rapidly deploy the network and flexibly adjust the

network layout.

This feature helps reduce the workload of manual configuration once the network is

adjusted.

Description

The BTS3900B is a new generation pico base station launched by Huawei. It is small and

light, has the plug-and-play feature, and supports indoor installation. The automatic

configuration and planning function of the BTS3900B provides simple and easy installation

for operators.

After being equipped with hardware and powered on, the BTS3900B automatically performs

the internal check to confirm that the hardware is properly installed. After the self-check is

complete, the BTS3900B automatically configures the parameters related to IP transmission

and establishes the encrypted IP transmission links with the BSC and the M2000. Then, the

BTS3900B reports its device configurations to the M2000. The M2000 calculates the




206

available radio parameters automatically based on the information about the frequency bands

and ambient radio environment reported by the BTS3900B, and then sends the parameters

including frequencies, BSIC, CGI, and so on to the BSC to configure based on the parameters.

After the basic parameters are configured, the BTS3900B can work normally and process

services.

After the network runs for a period of time, you can manually initiate the automatic planning

procedure of the BTS3900B through the M2000 if the network adjustment is required. Only a

few manual configurations are required during the automatic planning procedure. Therefore,

the BSC provides a mechanism of reporting event alarms to timely notify users of any

exception during automatic planning.

Enhancement

None

Dependency


None




None



WOFD-180800 Pico BTS Automatic Planning-GBSS

6.1.2 GBFD-510602 PICO Synchronization

Availability


Summary

The pico base station is BTS3900B. The BTS3900B implements the frequency

synchronization on the Um interface by demodulating the signals on the frequency correction

channel (FCCH) and synchronization channel (SCH) on the main BCCH in the surrounding

macro BTSs and then adjusting the frequency offset.

Benefits

With this feature, operators need to provide neither the external clock source nor the GPS

hardware for frequency synchronization, saving the cost of deploying sites and O&M cost.




207

Description

In the GSM network, the frequencies must be synchronized on the Um interface among BTSs.

Otherwise, the network quality is affected. For example, the handover success rate drops. At

present, four solutions are employed to implement frequency synchronization on the Um

interface: external BITS clock, IPCLK, upper-level BSC clock, and GPS clock. All these four

solutions require the external clock source or the GPS hardware, and therefore are not

applicable to the indoor BTS3900B.

This feature, however, can implement frequency synchronization on the Um interface

between the pico base station and the surrounding macro BTSs by using software to provide

the 13 MHz synchronization clock.

The BTS3900B applies for frequencies of neighboring cells for synchronization and

modulates the FCCH and SCH to select a target frequency. Then, the BTS3900B calculates

the frequency offset to the target frequency and corrects its frequency to achieve frequency

synchronization on the Um interface.

Enhancement

None

Dependency


None




None


None

6.1.3 GBFD-510603 PICO Dual-band Auto-planning

Availability


Summary

A BTS3900B is a PICO base station. Dual-band automatic planning is an extension of the

existing single-band automatic planning. The PICO Dual-band Auto-planning feature supports

automatic planning of the frequencies on the 900 MHz and 1800 MHz frequency bands or on

the 850 MHz and 1900 MHz frequency bands.

Benefits

The PICO Dual-band Auto-planning feature enables more flexible and high-quality network

planning. Therefore, the site construction workload and the maintenance cost are reduced.




208

Description

After the PICO Dual-band Auto-planning feature is introduced, the BTS3900B supports not

only single-band automatic planning but also automatic planning of the frequencies on the

900 MHz and 1800 MHz frequency bands or on the 850 MHz and 1900 MHz frequency

bands.

The BTS3900B scans the uplink and downlink frequencies specified by the operator and then

reports the frequency scanning result to the M2000. Based on the frequency scanning result,

the M2000 evaluates the interference to each frequency. The M2000 then considers the

neighboring relationships of the surrounding base stations to select the frequency with the

minimum interference as the working frequency of the BTS3900B.

The BTS3900B supports three frequency planning modes. The operator can select a proper

mode according to the actual conditions.

1. Co-BCCH dual-band cell mode: The M2000 allocates the BCCH frequency on the low

frequency band, for example, the 900 MHz or 850 MHz frequency band, and then allocates a

TCH frequency on the low or high frequency band.

2. Band adaptive selection mode: Based on the dual-band frequency scanning result reported

by the BTS3900B, the M2000 selects the frequency with the minimum interference as the

working frequency. The frequency band of the selected frequency becomes the working band

of the BTS3900B. That is, the M2000 configures the BTS3900B as a single-band cell on the

working band.

3. Specified band mode: The BTS3900B scans the frequencies on the two frequency bands

and then reports the frequency scanning result to the M2000. The M2000 selects the working

frequency only from the specified frequency band. The M2000 then configures the

BTS3900B as a single-band cell on the specified frequency band.

Enhancement

None

Dependency


None


Only the BTS3900B supports this feature.


None



WOFD-180800 Pico BTS Automatic Planning-GBSS




209

6.1.4 GBFD-510604 PICO USB Encryption

Availability


Summary

A BTS3900B is a PICO base station. When a BTS3900B is locally commissioned, a USB

device is used to save the configuration file. The PICO USB Encryption feature enables the

encryption of the configuration file in the USB device so that the file is not displayed as plain

text. In this way, the risk of disclosure of the configuration file is reduced.

Benefits

The risk of disclosure of information because the files in the USB device are lost or stolen is

reduced.

Description

When a BTS3900B is locally commissioned, a USB device is used to save the configuration

file. This file contains important configuration information, such as the IP addresses of

network elements and IPsec keys. If the information is saved as plain text, it may be stolen or

disclosed.

After the PICO USB Encryption feature is introduced, the configuration file is encrypted by

using encryption software on the M2000 side and then is decrypted on the BTS side. In this

manner, the configuration file in the USB device is not displayed as plain text, ensuring

information security.

Enhancement

None

Dependency


None




None


The M2000 needs to support this feature.




210

6.1.5 GBFD-510605 PICO Access Control List (ACL)

Availability


Summary

A BTS3900B is a PICO base station. The BTS3900B filters out illegal packets at the

receiving ports after packet analysis so that these packets do not enter the BTS3900B. In this

manner, the robustness and anti-attack capability of the BTS3900B are improved.

Benefits

The anti-attack capability of the BTS3900B in an IP transport network is improved.

Description

In IP transmission mode, the BTS3900B can use an existing public IP transport network to

transmit data. Compared with a private transport network, the public transport network has

greater security vulnerabilities and is more vulnerable to hacker attack.

The ports of the BTS3900B can filter the received packets. These ports receive and process

only the ARP, DHCP, DNS, ISAKMP (IKE), ESP, TCP, and ICMP packets but discard the

packets of other types. The BTS3900B filters out illegal packets so that they do not enter the

BTS3900B. Therefore, the CPU usage of the BTS3900B is reduced. To some extent, the

stability and the anti-attack capability of the BTS3900B are also improved.

Enhancement

None

Dependency


None




None


None

6.1.6 GBFD-510606 PICO Sleeping Mode

Availability





211

Summary

A BTS3900B is a PICO base station. In the specified period, the TRX power amplifiers of the

cell under a BTS3900B can be shut down to reduce power consumption.

Benefits

Power consumption is reduced by shutting down network devices during the period when

there is no traffic. Therefore, the OPEX is cut down.

Description

The BTS3900B is an industry-leading compact PICO base station. It features small size,

flexible site selection, and easy installation, enabling fast and cost-effective blind-spot

coverage. In some temporary blind-spot coverage areas, such as office areas, temporary

meeting rooms, temporary exhibition halls, and warehouses, wireless communication services

are not required in the period when there is no traffic, for example, at night.

With the PICO Sleeping Mode feature, the cell under the BTS3900B can be shut down in the

specified period to reduce power consumption. The operator can specify the period during

which a PICO cell is shut down, for example, between 0:00 a.m. and 6:00 a.m. During this

period, the power amplifiers of all the TRXs (including the BCCH TRX) in the cell are shut

down. In PICO sleeping mode, wireless communication services are unavailable within the

coverage area of the PICO cell.

Enhancement

None

Dependency


None




None


The M2000 needs to support this feature.

6.1.7 GBFD-510607 PICO Automatic Optimization

Availability





212

Summary

A BTS3900B is a PICO base station. If the working frequency of an operational BTS3900B is

severely interfered, the BTS3900B can perform automatic frequency planning under the

control of the M2000.

Benefits

After this feature is introduced, the BTS3900B automatically improves the network QoS

when its working frequency is interfered. In this manner, the network optimization workload

and the maintenance cost are reduced.

Description

The M2000 periodically analyzes the uplink and downlink interference-related traffic

statistics of the BTS3900B. When the working frequency of the BTS3900B is found severely

interfered, the M2000 instructs the BTS3900B to restart uplink and downlink frequency

scanning. Based on the frequency scanning result, the M2000 selects the frequency with the

minimum interference as the working frequency of the BTS3900B.

Through automatic optimization of the working frequency, the BTS3900B avoids using the

frequency with severe interference so that the speech quality and traffic KPIs in the coverage

area are improved significantly. Accordingly, in the coverage area, the handover success rate

increases whereas the call drop rate decreases.

Enhancement

None

Dependency


None




None



WOFD-170100 Pico BTS Frequency Automatic Optimizing-GBSS

6.1.8 GBFD-510608 PICO Transceiver Redundancy

Availability





213

Introduction

A BTS3900B supports a maximum of two transceivers (TRXs). Usually, one TRX operates

and the other TRX is idle. After this feature is introduced, one TRX automatically starts

operating if the other TRX malfunctions.

Benefits


Reduced out-of-service duration

Decreased OM workload

Description

When one TRX configured for a BTS3900B malfunctions, the BTS3900B is reset

automatically. After the BTS3900B restarts, it reconfigures the data on the other TRX. Then,

the BTS3900B starts operating again.

This type of switchover also can be performed manually in remote mode.

Enhancement

None

Dependency


None




None


None

6.2 EasyGSM Solution

6.2.1 GBFD-510701 Compact BTS Automatic Configuration and Planning

Availability





214

Summary

The Compact BTS is BTS3900E. After being installed and powered on, the BTS3900E can

connect to the BSC automatically. Operators do not need to configure radio parameters for

cells. The M2000 obtains radio parameters based on frequency bands and scanning results of

the uplink and downlink level of surrounding frequencies reported from the BTS, and then

performs the automatic configuration and planning of the BTS39000E.

Benefits This feature helps operators to rapidly deploy the network and flexibly adjust the

network layout.

This feature helps reduce the workload of manual configuration once the network is

adjusted.

Description

The BTS3900E is a new generation pico base station launched by Huawei. It is small and

light, has the plug-and-play feature, and supports indoor installation. The automatic

configuration and planning function of the BTS3900E provides simple and easy installation

for operators.

After being equipped with hardware and powered on, the BTS3900E automatically performs

the internal check to confirm that the hardware is properly installed. After the self-check is

complete, the BTS3900E automatically configures the parameters related to IP transmission

and establishes the encrypted IP transmission links with the BSC and the M2000. Then, the

BTS3900E reports its device configurations to the M2000. The M2000 calculates the

available radio parameters automatically based on the information about the frequency bands

and ambient radio environment reported by the BTS3900E, and then sends the parameters

including frequencies, BSIC, CGI, and so on to the BSC to configure based on the parameters.

After the basic parameters are configured, the BTS3900E can work normally and process

services.

After the network runs for a period of time, you can manually initiate the automatic planning

procedure of the BTS3900E through the M2000 if the network adjustment is required. Only a

few manual configurations are required during the automatic planning procedure. Therefore,

the BSC provides a mechanism of reporting event alarms to timely notify users of any

exception during automatic planning.

Enhancement

None

Dependency


None




None




215



WOFD-180900 Compact BTS Automatic Planning-GBSS

6.2.2 GBFD-510702 Compact BTS Automatic Capacity Planning

Availability


Summary

The Compact BTS is BTS3900E. According to the traffic volume, the BSC adjusts the output

power of the TRX in real time to achieve the balance between capacity and coverage of the

network. A cell is initially configured with one TRX of 30 W power. With the increase of the

traffic volume, another TRX in the cell is automatically activated, and these two TRXs share

the 30 W power.

Benefits

With this feature, the network capacity and coverage can be automatically adjusted without

manual intervention, reducing the maintenance cost.

Description

At the early stage of site deployment, the traffic volume is low. Therefore, the BTS is

configured with one TRX, which transmits with 30 W on the GSM900 frequency band. With

the slow increase of the traffic volume, when the preset threshold is exceeded, the BSC

automatically configures two TRXs, with the total transmit power no more than 30 W. During

the operation of the BTS, the system adjusts the TRX transmit power in real time according to

the change of the traffic volume. In this way, the coverage is changed, achieving the optimal

network performance. This feature mainly applies to the scenario where there are few

neighboring cells and the network structure is simple, especially, where the network

experiences slow increase of traffic volume.

Enhancement

None

Dependency


None




None




216



WOFD-181000 Compact BTS Automatic Capacity Planning-GBSS

6.2.3 GBFD-510704 Compact BTS Automatic Neighbor Cell Planning and Optimization

Availability


Summary

The compact BTS is also referred to as the BTS3900E. After this feature is enabled, the

M2000 analyzes the scanning information of the downlink frequencies reported by the

BTS3900E and therefore obtains the information about the neighboring cells. Based on the

obtained information, the M2000 performs the neighboring cell planning of the BTS3900E. If

the M2000 determines that the compact BTS has redundant or missing neighboring cells by

analyzing the measurement reports, the M2000 triggers the automatic neighboring cell

optimization to update neighboring cell relationships.

Benefits The network performance is improved without manual intervention. The handover

success rate is increased and the call drop rate is decreased.

The workload for manually configuring neighboring cells is greatly reduced to improve

the operation and maintenance efficiency.

Description

The BTS3900E is a new type of Huawei compact BTS. It is small, light, and has the feature

of plug-and-play. It is used in indoor spaces and rural areas. This feature facilitates the

installation of the BTS3900E.

The following events occur in automatic neighboring cell planning. The M2000 enables the

BTS3900E to scan downlink frequencies and then the BTS3900E reports the information

about neighboring cells to the M2000. After that, the M2000 adds the scanned cells to the

neighboring cell list of the cell under the BTS3900E and adds the cell under the BTS3900E to

the neighboring cell list of the scanned cells. Therefore, bidirectional neighboring cell

relationships are created. If the scanned cells are not controlled by the M2000, the M2000 can

create only unidirectional neighboring cell relationships.

If the M2000 determines that the BTS3900E has redundant or missing neighboring cells by

analyzing the measurement reports, the M2000 triggers the automatic neighboring cell

optimization to update neighboring cell relationships.

Enhancement

None




217

Dependency


None




None


The following M2000 features must be activated:

WOFD-181100 Compact BTS Frequency Automatic Optimizing-GBSS

WOFD-181200 Compact BTS Automatic Neighboring Relation Optimization-GBSS

6.2.4 GBFD-510705 Compact BTS Timing Power Off

Availability


Summary

In rural areas, MS users habitually do not make phone calls at night. Therefore, the traffic of

the compact BTS (BTS3900E) is extremely light during such period. This feature allows the

BTS to be powered off and on at night as scheduled. In this manner, the power consumption

of the BTS can be reduced. The power-off and power-on times can be configured on the BSC.

Benefits

This feature helps reduce the power consumption of the BTS at night when there is little

traffic. It can reduce the CAPEX on deploying BTSs powered by solar energy, because the

reduced power consumption leads to fewer required solar panels, smaller footprint, and

decreased costs in site construction and auxiliary devices.

Description

This feature can be applied to rural coverage scenarios where MS users habitually do not

make phone calls at night. With this feature, the BTS can be powered off and on as scheduled

during the period. The feature is applicable to the following powering scenarios:

1. BTS3900E Powered By Electricity Grid

In such a powering scenario, the BTS is not powered by solar energy. Telecom operators can

specify the power-off and power-on times of the BTS3900E according to the habits of local

MS users, so that the BTS can sleep at night, for example from midnight to 5 o'clock. When

sleeping, the BTS shuts down some RF devices to reduce power consumption. After this

feature is applied to BTS3900E O2, the power consumption of the BTS can be reduced by

100 W.

2. BTS3900E Powered By Solar Energy




218

In this scenario, this feature can be used in combination with the solar controller. Telecom

operators can set the power-off and power-on times of the BTS3900E on the BSC. The

BTS3900E is then powered off and on by the solar controller as scheduled. After the

BTS3900E is powered back on, it automatically establishes the connection to the BSC and

resumes to the functional state. Compared with the BTS powered by electricity grid, the BTS

powered by solar energy will be completely shut down during the specified power-off period,

therefore not consuming any power.

Note that the BTS3900E cannot process any service during the power-off period. It cannot

automatically wake up or power on even if there are service requests.

In conclusion, this feature contributes a lot to the reduction of power consumption, especially

in the case of the BTS3900E powered by solar energy. It also helps reduce the number of

solar panels to a minimum without comprising the quality of service. In this way, the CAPEX

on the solar energy devices, which counts for a large percent of the total investment in a site,

can be reduced.

Enhancement

None

Dependency


None




None


The M2000 needs to support this feature. The Power2000, an auxiliary power supply product,

is required.

6.2.5 GBFD-510706 Local User Management

Availability


Summary

This feature is applicable to a special business mode. In this business mode, the operator

contracts out the BTS3900E deployed in a remote rural area to an entrepreneur (hereafter

called "village chief"). The village chief then performs local user management. Local user

management involves the following aspects:

1. User registration and deregistration

2. Local services

3. Public network services




219

4. Local services in single-BTS3900E mode

Benefits

The Local User Management feature enables the operator to launch a new business mode so

as to develop a new market.

After the operator contracts out a BTS3900E to the village chief, the village chief gains

profits by providing local services for the users in the village. The village chief is

responsible for performing local user registration, working out the charging policy, and

charging local users for their communications.

Local user management in a remote rural area can be performed even if the transmission

between the public network and the local network is interrupted. In addition, calls can be

made between local users and the calls can be charged.

The BTS3900E purchased by the village chief can provide services for public network

users of the operator.

In the case that the communication between the BTS3900E and the BSC is interrupted,

the BTS3900E attempts to meet the communication requirements of public network

users.

Description

The Local User Management feature involves the following aspects:

1. User registration and deregistration

The village chief that contracts for the BTS3900E purchases a set of SIM cards from the

operator. These SIM cards are registered in the operator's network but not registered in the

local network. The village chief then sells these SIM cards to the villagers while registering

the SIM cards in the local network. Subsequently, the villagers can use mobile phones with

these SIM cards to make local calls and external calls.

The MSs that are registered in the local network covered by the BTS3900E of the village

chief are called local users, whereas other MSs are called public network users.

The village chief uses a PC to perform user registration. The user information, such as the

MSISDN, IMSI, prepaid fee, and balance are stored on the PC.

When a public network user roams into the coverage area of the BTS3900E, the village chief

manually adds this user to the local network so as to meet the communication requirements of

the public network user.

2. Local services

When local user A and local user B camp on the network covered by the BTS3900E of the

village chief, the calls made by the two users and the short messages transmitted between

them are called local services. The charging of local services is performed at the PC. The

village chief uses this PC to print the call detail records (CDRs) of all local calls.

Regarding the prepaid users, the PC periodically updates the balance information. Currently,

only the monthly fee charging is supported.

With respect to local services, the CN neither participates in the service signaling procedure

nor records CDRs. Therefore, legal interception, authentication, and encryption cannot be

performed.

3. Public network services




220

All users except the local users are called public network users. The calls, such as a call made

by a local user after it moves to the coverage area of another base station, or a call made by a

public network user after it moves to the coverage area of the BTS3900E of the village chief,

are called public network services.

When a local user moves to the coverage area of another base station, all the charging and

calls of this user are processed by the MSC. The village chief combines the CDRs of local

calls and the CDRs generated by the public network to calculate the communication fee of the

local user. After charging the local user for the communication fee, the village chief makes fee

settlement with the operator.

4. Local services in single-BTS3900E mode

When the transmission over the Abis interface is interrupted, the BTS3900E enters the

single-BTS3900E mode. In this mode, the BTS3900E independently processes all local calls.

When the transmission over the Abis interface recovers, the BTS3900E automatically

switches from the single-BTS3900E mode to the normal work mode.

If a non-local user enters the coverage area of the BTS3900E in single-BTS3900E mode and

the village chief does not register this user in the local network, the BTS3900E allocates a

temporary MSISDN to the user and notifies the user of the MSISDN through a short message.

Subsequently, normal communication services can be processed between the non-local user

and local users. The BTS3900E records the CDRs of all users, including local users and

non-local users. A CDR contains the fundamental information about a user, such as the IMSI.

Enhancement

None

Dependency


None







None

6.2.6 GBFD-111613 Weather Adaptive Power Management

Availability





221

Summary

This feature checks the strength of solar radiation and estimates the power consumption of a

site using solar energy as its power supply. Based on the checking and estimation results, the

energy consumption behavior, serving time, and service quality of the site can be determined.

This feature helps prolong the serving time of the site and minimize the possibility of the site

running out of power, while ensuring the desirable service quality. Ultimately, this feature

optimizes the deployment of the energy equipment and consequently reduces the related

costs.

Benefits The power consumption of the sites is reduced. As a result, the emission of carbon

dioxide is decreased.

The deployment of the energy equipment is optimized, reducing the related costs and

enhancing the reliability of power supply.

Description

The administrator/operator configures the related parameters and enters the weather forecast

data on the M2000.

The BTS obtains from the solar energy controller the information on the power generation

capacity of the solar panel, power consumption of the BTS, and remaining capacity of the

storage battery. It reports the collected information to the M2000 periodically. The M2000

adjusts the transmit power of the BTS to a proper value based on the estimated power

generation capacity (depending on the weather conditions), the actual power generation

capacity of the solar panel, and the remaining capacity of the storage battery. This prolongs

the battery life and reduces the possibility of the BTS running out of power.

Enhancement

None

Dependency


None




None



WOFD-170600 Weather Adaptive Energy Management-GBSS




222

6.3 Auxiliary Equipment Management

6.3.1 GBFD-510710 Intelligent Battery Management

Availability


Summary

With this feature,

The battery management mode automatically changes depending on the selected grid

type, which prolongs the battery lifespan.

The battery self-protection function is triggered under high temperature, which avoids

the overuse of batteries and the consequent damages to the batteries.

The runtime of batteries is displayed after the mains supply is cut off. According to the

runtime, users can take measures in advance to avoid service interruption due to power

supply cutoff.

Benefits

Prolonged battery lifespan

Less energy consumption

Reduced operation costs

Improved system stability

Description

Automatic change of the battery management mode:

The PMU board records the number of times power supply is cut off and the duration of each

cutoff. Then, the PMU board determines which grid type is chosen and correspondingly

activates a specific power management mode. In grid types 1 and 2, batteries can enter the

hibernation state in which batters do not charge or discharge, which helps prolong battery

lifespan.

Power Supply

Cutoff Duration

Within 15 Days

(Hours)

Grid

Type

Charge and

Discharge

Mode

Current

Limitation

Valve

Hibernation

Voltage (V)

Hibernation

Duration

(Days)

Estimated

Battery Lifespan

Improvement

Rate

≤ 5 1 Mode A 0.10 C 52 13 100%

5-30 2 Mode B 0.15 C 52 6 50%

30-120 3 Mode C 0.15 C N/A N/A 0%

≥120 4 Mode C 0.15 N/A N/A 0%




223

The function of the automatic change of the battery management mode is under license

control. In addition, this function is disabled by default and you can enable it by running an

MML command.

Self-protection under high temperature:

When batteries maintain a temperature exceeding the threshold for entering the floating

charge state for 5 minutes, they enter the state and no alarms are generated.

When batteries maintain a temperature exceeding the threshold for the self-protection

function for 5 minutes, they are automatically powered off or the voltage of batteries is

automatically adjusted.

Display of the battery runtime:

After the mains supply is cut off, the base station works out the runtime of batteries based on

the remaining power capacity, discharge current, and other data. This runtime can be queried

by running an MML command.

To calculate the runtime of batteries, use the following formula:

Runtime of batteries = (Remaining power capacity x Total power capacity x Discharge

efficiency)/(Mean discharge current x Aging coefficient)

Enhancement

None

Dependency


None




The PMU must be of a version that supports this feature.

A license is required to activate the feature.


None




Page 224 of 362

7 Network Performance

7.1 Coverage Enhancement

7.1.1 GBFD-115901 PBT(Power Boost Technology)

Availability


Summary

The Power Boost Technology (PBT) enables the DTRU to transmit the combined signals with

high gain and to achieve extended network coverage.

Benefits


This feature can realize the mutual transformation between the network coverage and the

network capacity.

In the initial network deployment stage, the operators can use the PBT to extend the

network coverage, reducing the number of BTSs.

When the subscriber number increases and the network capacity needs to be expanded,

operator can transform the PBT-enabled single TRX into two common-mode TRXs,

protesting the hardware investment.

Description

In the DTRU, two TRXs are integrated into a TRX module that is configured with a combiner.

The combiner combines the radio signals of the same frequency and same phrase from two

TRXs, and then transmits the combined signals. In this way, the downlink transmit power is

higher than the transmit power of the original signals, and the transmit power with high gain

is achieved and the downlink coverage is extended.

Enhancement

None




225

Dependency


None




None


None

7.1.2 GBFD-115902 Transmit Diversity

Availability


Summary

To enable this feature, the two TRXs in the DTRU are connected to the two separated antenna

feeders respectively, and the two antennas transmit the same downlink signal on the same

frequency. Through the introduction of the controllable delay and changeable phase between

two signals of the two TRXs, the diversity gain in terms of time and space can be obtained,

enhancing the RX signals and reducing the signal attenuation. This in turn, extends the

network coverage.

Benefits


This feature can realize the mutual transformation between the network coverage and the

network capacity.

This feature can effectively extend the downlink coverage, reducing the number of

required BTSs.

When the requirement for the network coverage decreases and the requirement for the

capacity increases, operator can transform the transmit diversity-enabled single TRX into

common-mode TRXs.

Description

The feature enables the two TRXs that are integrated in the DTRU to transmit the correlated

signals on the same frequency. This provides two independent downlink multi-path signals,

and these signals are processed by the equalizer of the MS. In this way, the diversity gain is

obtained, and the quality of the RX signal is improved. Therefore, the downlink coverage is

improved. If the DTRU works in single TRX mode, this feature can be enabled through

remote data configuration.




226

Enhancement

None

Dependency


None






It is mutually exclusive with the following features when using RRU3008/RRU3908:

GBFD-118106 Dynamic Power Sharing (Dual PA power sharing)


None

7.1.3 GBFD-115903 4-Way Receiver Diversity

Availability


Summary

The 4-way receiver diversity technology allows four antennas (four uni-polarized antennas or

two dual-polarized antennas) to receive the mutipath uplink signals from one cell. Then the

received signals are combined. Compared with two-way receiver diversity, four-way receiver

diversity can improve the receive sensitivity, extending the uplink coverage.

Benefits

The 4-way receiver diversity technology can enhance the uplink RX signal strength by

increasing the receive gain of the BTS antennas without increasing the transmit power of the

MS. In this way, the cell coverage is extended and the improved QoS can be achieved.

Description

The coverage of a cell is determined by the transmit power of the BTS and MS, and the

receive gain of the BTS antenna. Because the transmit power of an MS is much lower than

that of a BTS, in most cases, the actual coverage is lower than the designed value and the

voice quality deteriorates.

With appropriate design, the 4-way receiver diversity technology allows one TRX module to

receive the uplink signals from four RX channels and then combine the uplink signals to

achieve better signal quality and demodulation performance. Therefore, the receive sensitivity




227

is improved, and the receive effect is much better than that of none receiver diversity and that

of two-way receiver diversity.

Enhancement

None

Dependency


None




None


None

7.1.4 GBFD-118101 Dynamic Transmit Diversity

Availability


Summary

Dynamic transmit diversity is timeslot-based transmit diversity.

Benefits

Currently, the TRX-based transmit diversity is applied. In this case, a double-transceiver unit

serves as a single-transceiver unit. However, timeslot-based dynamic transmit diversity

maintains optimal balance between capacity and coverage.

Dynamic transmit diversity makes fully use of idle timeslots and expands the coverage in the

areas with weak signals, such as at cell borders, indoors, or in cars. This feature helps save

network resources and capacity. Based on actual network conditions, the application on some

timeslots helps expand the coverage and improve the downlink output capacity, balancing the

traffic volume and coverage.

Dynamic transmit diversity can increase the handover success rate of the MSs at the border of

a cell. This is mainly used to improve the concentric performance when the co-BCCH

function is enabled.

Description

Dynamic transmit diversity is timeslot-based transmit diversity. One MS occupies one TCH

during a call, and the voice quality is monitored by the MR. If the voice quality of an MS is lower than the predefined threshold, the network enables dynamic transmit diversity to assign

the same timeslots on two adjacent TRXs to the MS. The signals carried on the two timeslots




228

are the same, and the phases are also identical. The signals are sent out through different

transmit ports and then enhanced through signal combination. Therefore, the receive quality

of the signals is improved. If the channel of the same timeslot of the adjacent TRX is

occupied by an MS, the intra-cell handover is performed to switch the MS to an idle channel

so that the adjacent channel can be used for dynamic transmit diversity. The receive quality of

the MS that is switched to an idle channel is good. Therefore, no call drop occurs during the

handover.

If the voice quality is higher than the predefined threshold, the network disables dynamic

transmit diversity and then releases the adjacent channel.

Compared with common transmit diversity, dynamic transmit diversity does not decrease the

capacity by half. It can achieve a balance between capacity and coverage and realize flexible

conversion.

Enhancement

None

Dependency


None




This feature depends on GBFD-113201 Concentric Cell.





It is mutually exclusive with the following features when using multi-carrier RRU dynamic

TX diversity:

GBFD-118106 Dynamic Power Sharing(Dual PA power sharing)


None

7.1.5 GBFD-118102 Dynamic PBT (Power Boost Technology)

Availability


Summary

Dynamic Power Boost Technology (PBT) is timeslot-based PBT.




229

Benefits

Currently, the TRX-based PBT is applied. In this case, a double-transceiver unit serves as a

single-transceiver unit. Timeslot-based PBT, however, maintains optimal balance between

capacity and coverage.

Dynamic PBT makes full use of idle timeslots and expands the coverage in the areas with

weak signals, such as at cell borders, indoors, or in cars. This feature helps save network

resources and capacity. Based on actual network conditions, this feature helps balance the

traffic volume and coverage.

Dynamic PBT can increase the handover success rate of the MSs at the border of a cell. This

helps improve the concentric cell performance when the co-BCCH function is enabled.

Description

Dynamic PBT is timeslot-based PBT.

One MS occupies one TCH during a call, and the voice quality is monitored by the MR.

If the signal strength of an MS is lower than the preset threshold, the network enables

dynamic PBT. In this case, the channels corresponding to the same timeslot of two TRXs

in one TRX module cannot be assigned to the MSs; whereas the RF channels serving as

backup channels can provide PBT service. The signals and the phases of the traffic

timeslot in the RF channel are the same as those of the same timeslot in the same TRX

module of the backup channel. The signals are strengthened after the combination, and

therefore the signal strength of MSs is enhanced.

If the channel of the same timeslot of the adjacent TRX is occupied by an MS, the

intra-cell handover is performed to switch the MS to an idle channel so that the adjacent

channel can be used for dynamic PBT. The receive quality of the MS that is switched to

an idle channel is good. Therefore, no call drop occurs during the handover.

If the signal strength of an MS is higher than the preset threshold, the network disables

dynamic PBT. Then, the borrowed channel is restored to the idle state and provides

access services.

Compared with common PBT, dynamic PBT does not decrease the capacity by half. It can

achieve a balance between capacity and coverage and realize flexible conversion.

Enhancement

None

Dependency


None




This feature depends on GBFD-113201 Concentric Cell.





230





None

7.1.6 GBFD-118104 Enhanced EDGE Coverage

Availability


Summary

This feature increases the maximum transmit power of PS services by using the coverage

enhancement and power sharing techniques, enlarging the coverage area of the EDGE

network. This feature is applicable to both dual-carrier TRXs and multi-carrier TRXs.

Benefits

The feature increases the TRX transmit power in the 8PSK modulation scheme and the data

throughput at cell border. This improves user experience.

Description

In a GSM network, CS services and low-rate PS services use the GMSK modulation scheme

(CS1–4 and MCS1–4); high-rate PS services use the 8PSK modulation scheme (MCS5–9). In

the case of the 8PSK modulation scheme, the peak-to-average power ratio (PAPR) of a TRX

will increase. Before the introduction of this feature, the transmit power of the TRX needs to

be rolled back by 1.8 dB to ensure the linear output of the power amplifier. The transmit

power on EDGE channels that uses the 8PSK modulation scheme decreases by comparison

with the GMSK modulation scheme. This leads to bad user experience.

To solve this problem, Huawei has developed the feature Enhanced EDGE Coverage. By

adopting the coverage enhancement and power sharing techniques, the maximum transmit

power of the PS service is increased. With this feature, the data throughput at cell border is

increased. This feature is applicable to both dual-carrier TRXs and multi-carrier TRXs.

With respect to the dual-carrier TRX, the maximum transmit power of the PS service is

increased by using the dynamic transmit diversity and dynamic power boost technology (PBT)

techniques on the same timeslot of different carriers. In this way, the cell coverage of the PS

service can be comparable to that of the CS service.

With respect to the multi-carrier TRX, the maximum transmit power of the PS service is

increased by allocating the power margin of the multi-carrier TRX to the 8PSK traffic channel.

The power margin always exists because the power amplifier of the multi-carrier TRX does

not transmit signals at full power in most cases due to power control and the existence of idle

timeslots. By using the power margin, the cell coverage of the PS service can be comparable

to that of the CS service.

The maximum transmit power in the 8PSK modulation scheme should not exceed that in the

GMSK modulation scheme. Therefore, the network planning will not be affected.




231

Enhancement

None

Dependency


None





GBFD-114201 EGPRS




None

7.1.7 GBFD-118106 Dynamic Power Sharing

Availability

This feature is available from GBSS13.0.

Summary

The output power can be shared between TRXs at the timeslot level and be dynamically

adjusted to increase the network coverage.

Benefits

This feature increases the output power of TRXs, enhances the cell coverage, and improves

the power utilization of the Power Amplifier (PA).

Description

Dynamic Power Sharing is a type of cell coverage maximization solution that aims to meet

different power requirements of users distributed in different areas of a cell.

Users distributed in different areas of a cell require different transmit power to access the

radio network. Generally, users near the BTS require low transmit power; whereas users far

from the BTS require high transmit power. The Dynamic Power Sharing feature dynamically

adjusts the transmit power of channels according to the power required by different calls to

meet the power requirements of users far from the BTS. When the user distribution in a cell

dynamically changes, the dynamic transmit power of the TRXs that are enabled with this

feature can be greater than the average available static power of the TRXs to increase the cell

coverage with the same PA output power.




232

Improvement on downlink coverage

In a network with poor downlink signal quality or low-speed downlink PS services, dynamic

power sharing can be enabled to reduce the proportion of users with weak coverage. This

improves speech quality and increases data throughput, thereby improving user experience

and reducing user complaints.

The Dynamic Power Sharing feature can be enabled only when the PA or PAs whose output

power is shared support the multi-carrier RF module. There are two types of Dynamic Power

Sharing, namely, single-PA dynamic power sharing and dual-PA dynamic power sharing.

Single-PA dynamic power sharing. Assume that the multi-carrier RF module GRFU is used.

The output power of three to six TRXs on the GRFU can be dynamically shared. The

single-PA dynamic power sharing function improves the output power compared with static

power.

Dual-PA dynamic power sharing. Assume that two GRFU modules are used. The TRXs

provided by the two GRFU modules work in the resource pool mode, and the output power is

shared between the TRXs in the resource pool. The dual-PA dynamic power sharing function

can further improve the output power of TRXs in large configuration scenarios.

When the dual-PA dynamic power sharing function is enabled, the operating frequencies of

the two RF modules must be within the Downlink Frequency Bandwidth (DFB) (for example,

the DFB is 12.5 MHz when the operating frequencies of the RRU share the output power of

one PA, and the DFB is 15 MHz when the operating frequencies of the RFU share the output

power of one PA). Currently, if the RRU is enabled with the dual-PA dynamic power sharing

function, the RRU must be configured in the single-cell single-module 2-way transmit mode.

If the RFU is enabled with the dual-PA dynamic power sharing function, the RFU must be

configured in the single-cell dual-module mode.

Huawei is committed to optimize the network KPIs through algorithm improvements during

dynamic power sharing. The network KPIs can be further optimized when this feature is used

together with Huawei network planning and network optimization services.

Enhancement

None

Dependency


None




This feature depends on the GBFD-119115 Power Control

The single-PA dynamic power sharing function cannot be used together with any of the

following features:

GBFD-117002 IBCA






233

GBFD-114001 Extended Cell (dual-timeslot extension function)

When the RFU uses the dual-PA dynamic power sharing function, the function cannot be used

together with any of the following features:

GBFD-111602 TRX Power Amplifier Intelligent Shutdown


GBFD-113201 Concentric Cell

GBFD-114501 Co-BCCH Cell

GBFD-113701 RF hopping(Inter-module)




When the RRU uses the dual-PA dynamic power sharing function, the function cannot be used

together with any of the following features:




GBFD-115902 Transmit Diversity

GBFD-118101 Dynamic Transmit Diversity

GBFD-117002 IBCA




Dependency on other NEs:

None

7.1.8 GBFD-114001 Extended Cell

Availability


Summary

The application of extended cell breaks the coverage limit of 35 km of a GSM cell. This helps

operators to provide wider coverage in special areas.




234

Benefits

The extended cell extends the coverage of the BTS and enables MSs to perform services in

long-distance areas, such as in vast plains and seas. In this way, the scope of network services

is extended and the network quality is improved.

Description

According to the GSM specifications, the maximum TA of a cell on the Um interface is 63

bits. Hence, the coverage radius of a cell cannot exceed 35 km. In the vast and sparsely

populated areas where the traffic is light and the transmission and power supply facilities are

unavailable, the cells with a coverage radius greater than 35 km are required. The extended

cell breaks the coverage limit of 35 km of a common cell. When this feature is enabled, the

coverage radius of a cell can reach up to 120 km. This feature enables operators to deploy the

GSM network rapidly in a cost-effective way in remote areas, improving the profitability.

If the coverage radius of a cell exceeds 35 km, the signal delay exceeds the maximum TA of

63 bits. When an MS moves to the border of the cell, the MS transmits signals with the

maximum permissible TA value. If the MS keeps moving outwards, the system cannot adjust

the TA value in an adaptive way because the TA has reached the maximum value. In this case,

some signals transmitted by the MS are sent to the BTS receiver on the next timeslot. To solve

this problem, the extended cell feature can be used. When this feature is enabled, two

continuous timeslots are assigned for each MS call and the receiver window of the BTS

receiver is also extended to the width of two timeslots. Therefore, the cell coverage radius is

extended to more than 35 km. To enable the MSs in the extended coverage area to initiate

calls at any time, the BCCH, CCCH, and SDCCH should be assigned two timeslots.

In the double-timeslot extended cell, the GPRS/EGPRS services are supported.

Enhancement

GBSS8.1

The downlink throughput is enhanced in the double-timeslot extended cell. In the cells with a

coverage radius of more than 35 km, such as coast coverage, island coverage, or wide

coverage on land, the MS supporting multislot capability can be assigned PDCHs for four

downlink timeslots and one uplink timeslot. The extended cell can provide a data throughput

that is four times higher than that in a common cell with a single downlink timeslot for

service establishment. This accelerates the download speed, enhances user experience, and

improves the data service profitability of operators.

Dependency


None










235

GBFD-115830 VAMOS



None

7.2 Capacity Improvement

7.2.1 GBFD-113201 Concentric Cell

Availability


Summary

A concentric cell consists of an overlaid subcell and an underlaid subcell. Different frequency

reuse patterns can be applied to the overlaid and underlaid subcells.

Benefits

The tight frequency reuse pattern is applied to the overlaid subcell. Therefore, the system

capacity is expanded without affecting the voice quality.

Description

With the number of subscribers increasing, frequency resources do not meet the growing

capacity demand. Therefore, tight frequency reuse must be applied to increase frequency

usage and network capacity. Tight frequency reuse, however, may greatly increase

interference and even result in deterioration of voice quality. It is necessary to reduce

interference and ensure voice quality in the tight frequency reuse pattern.

The concentric cell technology divides an ordinary cell into two service layers: overlaid

subcell and underlaid subcell.

For an MS in the underlaid subcell but not in the overlaid subcell, a TRX, such as the

BCCH TRX, in the loose frequency reuse pattern should be assigned.

For an MS in the overlaid subcell, a TRX, such as a non-BCCH TRX, in the tight

frequency reuse pattern should be assigned.

The tight frequency reuse pattern in the overlaid subcell improves the system capacity.

Compared with the MSs in the underlaid subcell, the MSs in the overlaid subcell are far from

the interference sources, and therefore the voice quality is guaranteed even if the tight

frequency reuse pattern is applied to the overlaid subcell. The voice quality of the MSs in the

underlaid subcell is also guaranteed when the loose frequency reuse pattern is applied.

When the capacity of the coverage area changes, the channels in the overlaid subcell and

underlaid subcell should be adjusted. For example, the traffic volume increases because a

large number of calls are made within a short period in the overlaid subcell. Adjusting the

TRX from the underlaid subcell to the overlaid subcell can expand the capacity of the

overlaid subcell and therefore solve the problem of burst traffic increase. When the traffic volume becomes light, the original settings are restored.




236

The BSS provides the power control, channel assignment, and handover algorithms regarding

the concentric cell to balance the traffic distribution in the concentric cell.

Enhancement

GBSS7.0

Support for Main BCCH Configured in Overlaid Subcell: The BCCH can be configured either

in the underlaid subcell or in the overlaid subcell. The BCCH configured in the overlaid

subcell can increase the network capacity because the tight frequency reuse pattern is applied

to the overlaid subcell. When the BCCH is configured in the overlaid subcell, the coverage

area of the overlaid subcell must be equivalent to that of the underlaid subcell. This can

reduce failures in handovers from the overlaid subcell to the underlaid subcell and reduce

failures in overlaid subcell assignments, improving the network performance.

Support for PDCH configured in Overlaid Subcell: The number of PDCHs increases with the

growth of PS services. This aggravates the TCH congestion in the underlaid subcell.

Configuring the PDCH in the overlaid subcell can absorb the PS services into the overlaid

subcell, minimizing the congestion in the underlaid subcell and increasing the capacity of the

concentric cell.

The parameters of concentric handover should be set for CS services and PS services

separately. This can implement timely handovers in CS domain and PS domain and reduce

call drops.

Dependency


None





GBFD-115830 VAMOS


None

7.2.2 GBFD-114501 Co-BCCH Cell

Availability


Summary

The co-BCCH cell refers to a cell where the TRXs on the GSM900/DCS1800,

GSM850/DCS1800, or GSM850/PCS1900 coexist. The TRXs on two bands are distributed in

the overlaid subcell and underlaid subcell that share one BCCH TRX. The co-BCCH cell can

expand the network capacity and reduce the interference between cells.




237

Benefits

This feature helps improve the cell capacity and reduce cell reselections and inter-cell

handovers for the MS.

In a co-BCCH cell, the overlaid subcell and underlaid subcell share one BCCH TRX,

reducing the number of BCCH TRXs and minimizing the interference between BCCH TRXs.

Description

The co-BCCH cell is based on the concentric cell. The TRXs on the GSM900 or GSM850 are

configured in the underlaid subcell to extend cell coverage; the TRXs on the DCS1800 or

PCS1900 are configured in the overlaid subcell to absorb traffic.

Before the channel assignment, the system determines the bands supported by the MS. If the

MS supports the bands in the underlaid and overlaid subcells, the channel assignment strategy

of the concentric cell is applied. Otherwise, only the channel in the underlaid subcell can be

assigned to the MS.

The system assigns channels on different bands to the MS based on the receive level, receive

quality, and TA value. The underlaid subcell is used for extending cell coverage and the

overlaid subcell is used for absorbing traffic. Therefore, the cell coverage is maximized and

the capacity balance between the overlaid subcell and the underlaid subcell is maintained.

In a co-BCCH cell, the TRXs on different bands belong to one cell, and one BCCH is shared

by both the underlaid subcell and overlaid subcell. Compared with the common dual-band

network, one BCCH is saved and used as a TCH, and therefore the system capacity is

enhanced. In addition, the TCHs on the two bands are integrated in a cell so that the channels

can be shared.

Enhancement

GBSS8.1

Support for different frequency hopping (FH) type used by TRXs in overlaid/underlaid

subcells: The FH type is not a cell-level parameter. In a cell, different TRXs may use different

FH types. Generally, the baseband FH is applied to the underlaid subcell because of

insufficient frequencies; whereas the RF FH is applied to the overlaid subcell because of

sufficient frequencies. This helps obtain a high FH gain.

Dependency


None







None




238

7.2.3 GBFD-114402 Enhanced Dual-band Network

Availability


Summary

The enhanced dual-band network is an improvement on the existing dual-band network. In the

enhanced dual-band network, two co-sited cells with different coverage areas logically form a

cell group. One is an overlaid subcell, and the other is an underlaid subcell. The enhanced

dual-band network algorithm enables channel sharing and load balancing between the two

cells in a cell group.

Benefits

The enhanced dual-band network enables a network to support multiple frequency bands and

enables operators to expand frequency bands.

If the KPIs are acceptable, the resource sharing of the overlaid and underlaid subcells expands

the system capacity.

This feature supports the tight frequency reuse pattern. The tight frequency reuse pattern is

applied to the overlaid subcell and the loose frequency reuse pattern is applied to the

underlaid subcell.

Description

Based on the multi-band network, the enhanced dual-band network enhances the channel

sharing of the overlaid and underlaid subcells.

The enhanced dual-band network enables two co-sited cells with different coverage areas to

form a cell group logically. The two cells are configured with the BCCH and SDCCH. One is

an overlaid subcell, and the other is an underlaid subcell. The enhanced dual-band network

algorithm enables channel sharing and load balancing between the two cells in a cell group.

The overlaid and underlaid subcells can obtain the information about each other, such as

signal level, channel, and load. Therefore, the KPIs such as the handover success rate and

assignment success rate can be kept at proper values when the channels in the overlaid and

underlaid subcells are shared.

The two cells cannot be assigned to two different operators.

Tight frequency reuse

In terms of functions, tight frequency reuse is similar to the concentric cell. In a cell

group of an enhanced dual-band network, loose frequency reuse can be applied to the

underlaid subcell, and tight frequency reuse is applied to the overlaid subcell. If an MS

accesses the network from the overlaid subcell and the load in the underlaid subcell is

low, the channel assignment is preferably performed in the underlaid subcell to minimize

the interference to the entire network. If an MS accesses the network from the underlaid

subcell and the load in the underlaid subcell is high, the channel assignment is preferably

performed in the overlaid subcell to achieve the traffic balance in the cell group. In

addition, the enhanced dual-band network supports dynamic distribution of the MSs that

are having calls according to the load and coverage.




239

Enhancement

None

Dependency


None




None


None

7.2.4 GBFD-117001 Flex MAIO

Availability


Summary

When this feature is enabled, the channels with less interference are preferentially selected

during channel assignment. If there is interference in the selected channel, the MAIO with the

minimum interference is assigned to the channel.

Benefits


Reduces the adjacent-channel and co-channel interference in the GSM system.

Achieves tight frequency reuse within the BTSs and therefore improves the system

capacity.

Description

Under the BTSs with large capacity, adjacent-channel or co-channel interference is likely to

occur among channels because the frequency resources are insufficient and tight frequency

reuse is adopted. For example, when some frequencies in the MA list are adjacent,

adjacent-channel interference occurs if the channels with the same timeslot number but on

different TRXs use adjacent MAIOs and are occupied at the same time.

When dynamic MAIO is enabled, the MAIO value is dynamically adjusted according to the

current interference and the MAIO value with the minimum interference is assigned to the

channel. Therefore, the call has the minimum interference from the perspective of the entire

network. Huawei BSS equipment records the interference on each timeslot and updates the

record during each channel activation or channel release.




240

Enhancement

None

Dependency


None





GBFD-113701 Frequency Hopping (RF hopping)


GBFD-117002 IBCA (Interference Based Channel Allocation)

GBFD-118106 Dynamic Power Sharing

GBFD-115830 VAMOS


None

7.2.5 GBFD-115801 ICC

Availability


Summary

When combining the signals from multiple antennas, the interference counteract combine

(ICC) uses interference correlation of different antennas to eliminate some interference.

Benefits


Improves the voice quality and data throughput in the scenarios with severe interference,

for example, where tight frequency reuse is applied, improving user experience.

Improves the anti-interference capability of equipment and increases the system capacity.

Description

ICC is a technology that suppresses the interference by combining signals of multiple

antennas. Generally, the interference on different antennas is generated by the same

interference source. Therefore, the interfering signals received by different antennas have a

certain correlation. ICC uses this correlation when combing signals to eliminate some




241

interference. In this way, ICC improves the anti-interference capability of equipment and

increases the uplink coverage and receiver sensitivity.

ICC can suppress the interference within the GSM system and from other systems only if the

interference on different antennas has a correlation.

Huawei BSS supports dual-antenna ICC and four-antenna ICC.

Enhancement

None

Dependency


None




This feature should be used in a synchronous network.

GBFD-118201 Soft-Synchronized Network

GBFD-118620 Clock over IP Support 1588v2

GBFD-510401 BTS GPS Synchronization


None

7.2.6 GBFD-115821 EICC

Availability


Summary

The interference on the signals received by multiple antennas has both spatial correlation and

temporal correlation: co-channel interference (CCI) and inter-symbol interference (ISI). After

considering the correlation of these two types of interference, EICC combines the signals

received by multiple antennas to provide better signal quality on the uplink.

Benefits


The EICC feature improves the uplink signal quality to meet the requirements for radio

communications and to improve the uplink performance in scenarios with wide

coverage.

With the uplink anti-interference capability improved, tight frequency reuse can be

achieved and therefore the system capacity is increased.




242

Description

Similar to ICC, EICC mainly applies to the network where the tight frequency reuse pattern is

adopted and the traffic volume is heavy.

The interference on the signals received by multiple antennas has both spatial correlation and

temporal correlation: CCI and ISI. Considering the spatial correlation and temporal

correlation of the interference, ICC eliminates these two types of interference independently.

EICC, however, considers the correlation of these two types of interference and constructs the

multidimensional combining coefficient matrix to combine the signals according to the

maximum signal-to-noise ratio (SNR) criteria. In this way, EICC obtains the optimized uplink

signals.

EICC requires the matrix of interference, which is calculated on the basis of the training

sequence of wanted signals. For each RX signal, the network estimates a channel model based

on the training sequence of the signal, reconstructs the wanted signal, and subtracts the

wanted signal from the RX signal to obtain the interfering signal. The network then estimates

the matrix of each interfering signal and analyzes the statistical dependency of these

interfering signals. Based on the statistical dependency, some interference is counteracted

during the combination of RX signals to maximize the combination gain.

Enhancement

None

Dependency


None




This feature should be used in a synchronous network.

This feature should be used with the following features:

GBFD-118201 Soft-Synchronized Network

GBFD-118620 Clock over IP Support 1588v2




None




243

7.2.7 GBFD-113701 Frequency Hopping (RF hopping, baseband hopping)

Availability


Summary

With this feature, wanted signals are transmitted by switching a carrier among many

frequencies according to the specified sequences. Frequency hopping involves RF hopping

and baseband hopping.

Benefits


This feature reduces the co-channel and adjacent-channel interference and therefore

improves the voice quality of the network.

The tight frequency reuse pattern can be adopted to increase the system capacity.

This feature improves the information security.

Description

With this feature, a traffic carrier frequency hops along the time according to the specified

sequence. Frequency hopping involves RF hopping and baseband hopping in terms of

implementation of the TRX. The frequency hopping enables operators to adopt the tight

frequency reuse pattern, increasing the system capacity while maintaining the good voice

quality. The frequency hopping feature minimizes the interference on a channel from the same

interference source. Therefore, it is widely used in the communications system because it

helps improve the anti-attenuation capability, anti-interference capability, and information

security.

In RF hopping, the frequencies for both transmitter and receiver of the TRX participate in

frequency hopping. The number of frequencies participating in the FH can exceed the number

of TRXs in the cell. RF hopping is implemented through the real-time switchover between

two frequency synthesizers. RF hopping has the following advantages:

RF hopping lowers the speed requirements on the frequency synthesizer.

When there is no FH, the two frequency synthesizers work in backup mode, enhancing

the system reliability.

RF hopping avoids the impact of the fast frequency conversion on the signal quality, and

therefore realizes the FH of all frequencies on the supported frequency band.

In baseband hopping, each transmitter works on a fixed frequency, and the TX does not

participate in FH. The TX frequency hopping is achieved though the switching of baseband

signals. The RX of the TRX, however, must participate in FH. Therefore, the number of

frequencies participating in FH in a cell must be less than or equal to the number of TRXs

assigned for the cell. When a TRX is faulty, the system enables the baseband FH TRX

cooperation to ensure that the voice quality in the cell is not affected by the faulty TRX.




244

Enhancement

GBSS9.0

Optimization of Baseband FH TRX cooperation:

In the baseband FH cell, if the TRX involved in baseband FH is faulty, remove the faulty

TRX from baseband FH group and continue FH with the good running TRX. Meanwhile the

same mechanism will take effect when main BCCH TRX cooperation happen, it will still

remain hopping with the baseband TRX.

GBSS12.0

Support RF hopping and baseband hopping at the same time in one cell

Dependency


None




Base band hopping is mutually exclusive with the following features:

GBFD-111604 Intelligent Combiner Bypass

GBFD-111606 Power Optimization Based on Channel Type


GBFD-118102 Dynamic PBT (Power Boost Technology)


None

7.2.8 GBFD-113702 BCCH Carrier Frequency Hopping

Availability


Summary

With this feature, non-BCCH timeslots participate in the baseband hopping, improving the

radio quality of non-BCCH timeslots and the cell performance.

Benefits

This feature helps improve the radio quality of non-BCCH timeslots on the BCCH carrier.




245

Description

In Huawei BSS, the non-BCCH timeslots on the BCCH TRX can participate in baseband

hopping in the cell. In this way, the baseband hopping performance is improved because the

number of frequencies participating in FH increases, and the performance of non-BCCH

timeslots on the BCCH TRX is improved because they also participate in the FH.

For the FH that the BCCH carrier participates in, the BCCH timeslot is not involved, but the

rest timeslots can participate in the baseband hopping.

According to the GSM specifications, the BCCH must be carried on a fixed frequency to

ensure the cell selection, cell reselection, and handover measurement. Therefore, the BCCH

carrier cannot participate in the RF hopping.

Enhancement

None

Dependency


None





Baseband hopping in GBFD-113701 Frequency Hopping (RF hopping, baseband hopping)


RF hopping in GBFD-113701 Frequency Hopping (RF hopping, baseband hopping)


None

7.2.9 GBFD-113703 Antenna Frequency Hopping

Availability


Summary

Similar to the baseband frequency hopping, the antenna frequency hopping enables the data of

all the timeslots on a specific carrier to be transmitted in turn on the antennas of other TRXs

in the cell. In this way, the space diversity is increased and the quality of the TRX data

received by the MS is improved, and therefore the network performance is improved.

Benefits





246

Increases the space diversity and improves the quality of BCCH TRX data received by

the MS, improving the network performance and reducing the network interference.

Increases the network capacity. Compared with the non-FH or FH with a few frequencies,

the antenna frequency hopping can increase the radio network capacity by up to 30% and

the network diversity gain by up to 3 dB.

Description


all carriers to be transmitted in turn on the antennas of other TRXs in the cell.

This feature applies to the BCCH on the BCCH TRX. The BCCH must be transmitted on the

same frequency. Therefore, the BCCH cannot hop by baseband hopping or RF hopping. In a

GSM cell, however, the frequency, frame number, system information, and paging group are

transmitted on the BCCH of the BCCH TRX. These broadcast messages are important for the

MS in idle mode to search for a network and for the MS in dedicated mode to measure the

neighboring cell. If the MS is located in a place where it is difficult to receive the messages

from the BCCH TRX or if the antenna for the BCCH TRX is damaged, then the MS cannot

properly receive the broadcast control messages from the BCCH TRX.


all timeslots on the BCCH TRX to be transmitted in turn on antennas of other TRXs. This

increases the space diversity of the BCCH signals and improves the quality of the data

received by the MS from the BCCH TRX, improving the network performance.

For example:

If a cell is configured with three TRXs and each TRX connects to one antenna with the

antenna frequency hopping enabled, the data of TRX 0 may be transmitted on antenna 1 at

this instant and on antenna 0 at the next instant, and then on antenna 2 at the third instant. In

this way, the space diversity is realized and therefore the receiver performance of the MS is

improved.

Enhancement

None

Dependency


None





GBFD-111602 TRX Power Amplifier Intelligent Shut down (in GBS9.0 and former version;

DRRU/DRFU support GBFD-111602 from GBSS12.0)


GBFD-118104 Enhanced EDGE Coverage

GBFD-111604 Intelligent Combiner Bypass




247

GBFD-111606 Power Optimization Based on Channel Type


GBFD-118102 Dynamic PBT (Power Boost Technology)


The BTS must support this feature, and at least two antennas are required in a cell to enable

antenna frequency hopping.

7.2.10 GBFD-118001 BCCH Dense Frequency Multiplexing

Availability


Summary

This feature allows the operator to adopt the tight frequency reuse pattern for the frequencies

of the BCCH carriers.

Benefits


The number of frequencies occupied by the BCCH carriers reduces, improving the

frequency usage. In addition, the number of frequencies available for the TCHs and the

number of frequencies participating in FH on the TCH increase, increasing the system

capacity and reducing the costs of adding sites and cells.

The TCHs on BCCH carriers are assigned to only the MSs near the BTS, improving the

voice quality because of less uplink interference.

Description

Each cell is configured with a BCCH carrier, and timeslot 0 on the BCCH carrier is used to

carry the BCH and CCCH. This timeslot continually sends messages to all the MSs camping

on the cell. The messages include the synchronization message, system information, paging

message, and assignment message, which are directly related to cell selection, cell reselection,

call initiation, and paging response. Therefore, the BCCH becomes the most important

channel in GSM communications.

Generally, the 4x3 pattern is adopted for the BCCH frequencies. This can ensure a high

carrier-to-interference ratio (CIR) between BCCH carriers. In this pattern, however, the

BCCH carriers occupy 12 frequencies. In a network with tight frequency reuse and limited

frequency resources, if the 3x3 pattern is used for the BCCH frequencies, the interference to

the TCH on the BCCH carrier increases and the performance degrades to an unacceptable

level.

This feature enables the BCCH frequencies to adopt the tight frequency reuse pattern. In this

way, in the network with limited frequency resources, the number of frequencies occupied by

the BCCH carriers decreases and the number of frequencies available for the TCHs increases,

increasing the system capacity without adding hardware and reducing the costs of adding

sites.




248

This feature regards a cell as two logical layers: TCH layer on BCCH carriers and FH layer

on other carriers.

The FH layer serves the entire system and covers the entire network, including the MSs at the

boarder of a cell. The TCH layer on the BCCH carrier, however, provides limited coverage to

ensure the performance of call access. The interference in the area near the BTS is smaller

than that in the area far from the BTS and at the edge of the cell. Therefore, the TCH layer on

the BCCH carrier provides the coverage only for the MSs near the BTS. During the initial

access and channel assignment triggered by handover (non-BCCH tight frequency

multiplexing), the system preferentially assigns TCHs on the non-BCCH carriers to ensure the

access performance. If a call is assigned a TCH on a non-BCCH carrier in the cell, the BCCH

Dense Frequency Multiplexing feature has less impact on the call if the MS is near the BTS.

The system then hands over the call to a TCH on the BCCH carrier and reserves the channels

on the non-BCCH carrier to ensure the access performance of other calls.

Enhancement

None

Dependency


None






GBFD-114501 Co-BCCH Cell

GBFD-114401 Multi-band Sharing One BSC


None

7.2.11 GBFD-117002 IBCA (Interference Based Channel Allocation)

Availability


Summary

When the network accesses a new call, the interference between the established calls and the

new call is calculated. Based on the calculation result, the network assigns a channel with the

minimum interference to the new call. This minimizes the overall interference in the network

and therefore enables a tighter frequency reuse pattern. This increases the network capacity while maintaining the voice quality in the entire network.




249

Benefits


Effectively improves the frequency usage and therefore improves the network capacity.

Reduces the overall interference and therefore improves the network performance.

Improves the voice quality of calls.

Description

In the GSM network, the loose frequency reuse provides better network performance, higher

network KPIs, and excellent voice quality, but reduces the network capacity compared with

the tight frequency reuse. The tight frequency reuse pattern can increase the network capacity,

but also increases the probability that the TRXs use the same frequency or adjacent

frequencies. This results in more co-channel or adjacent-channel interference, degrading the

network performance.

Based on the timeslot synchronization on the Um interface, the IBCA feature considers only

the channel-level interference. During the channel assignment, the IBCA considers the

interference strength of all idle channels and then preferentially assigns the channel with the

minimum interference. The IBCA feature involves the following functions:

Calculation of the interference to the new call caused by the established calls

The IBCA must be used together with frequency hopping. The idle channels with

different MAIOs transmit signals on the Um interface with different frequencies, and

therefore the interference that the idle channels experience from the established calls

varies. The IBCA calculates the interference strength on each idle channel when different

MAIOs are applied.

Calculation of interference to the established calls caused by the new call

The established calls cause interference to the new call. Similarly, the new call causes

interference to the established calls once it accesses the network. The IBCA estimates the

CIR of the new call to the established calls.

Considering the preceding two types of interference, the IBCA-enabled network assigns the

channel and MAIO with the minimum interference to the new call.

The IBCA feature consists of intra-BSC IBCA and inter-BSC IBCA. That is, the

IBCA-enabled cells may belong to one BSC or multiple BSCs.

The IBCA feature improves the frequency usage and therefore effectively increases the

network capacity. In addition, the IBCA-enabled network considers the interference to the

new call caused by the established calls, improving the voice quality of calls.

The network KPIs may be affected after the IBCA is applied. For example, the call drop rate

increases or the handover success rate decreases. Operators need to purchase Huawei's

professional services to minimize the impact of introducing IBCA on network KPIs.

Enhancement

GBSS12.0

IBCA Enhancement:

The limitation on the frequency hopping (FH) in an IBCA-enabled cell is lifted. The

limitation was that an IBCA-enabled cell can be configured with a maximum of three MA

groups and each MA group be configured with a maximum of 12 frequencies. After this




250

enhanced feature is enabled, the numbers of MA groups and frequencies are restricted only by

the BSC memory for cell information. This feature is suitable for sites with a large number of

frequencies.

Dependency


Embedded PCU should be used. Service processing boards should be added for processing

the IBCA-related services. The IP interface board should be added for the inter-BSC IBCA.





GBFD-118201 Soft-Synchronized Network or GBFD-510401 BTS GPS Synchronization

GBFD-113701 Frequency Hopping (RF hopping, baseband hopping)


GBFD-118621 Connection Inter BSC over IP (When IBCA of Inter-BSC is supported)



GBFD-110607 Direct Retry


GBFD-118001 BCCH Dense Frequency Multiplexing


None

7.2.12 GBFD-118201 Soft-Synchronized Network

Availability


Summary

When Soft-Synchronized Network feature is enabled, all the BTSs under a BSC synchronize

with each other by adjusting the frame number, timeslot number, and bit offset in the timeslot

to be the same through software. In a synchronous network, dynamic frequency allocation and

dynamic channel assignment can be adopted to minimize inter-cell co-channel and

adjacent-channel collision. This greatly improves the frequency usage and increases the

network capacity.

Benefits





251

This feature synchronizes all the BTSs under a BSC through software without additional

hardware devices.

After the BTSs are synchronized, the IBCA feature can be implemented. The IBCA

enabled in the synchronous network can improve the network capacity by 20% to 50%.

After the BTSs are synchronized, the performance of technologies such as ICC and

SAIC can be greatly improved. The ICC enabled in the synchronous network can

improve the network performance by about 5.5 dB compared with the performance in

the asynchronous network, and the SAIC enabled in the synchronous network can

increase the network capacity by about 40%.

This feature improves the KPIs such as MOS, paging success rate, handover success rate,

call drop rate, and traffic volume.

This feature realizes the software synchronization with the reference BTS, enabling the

flexible networking and reducing the workload of synchronization.

Description

Most of the existing networks work in asynchronous mode. That is, all BTSs are not

synchronized, and each BTS adopts a different frame number, timeslot number, and offset.

There are two network synchronization modes: hardware synchronization and software

synchronization.

In hardware synchronization mode, each BTS is equipped with a GPS device to realize

the network synchronization through the satellite. This requires expensive hardware

devices.

The Soft-Synchronized Network feature realizes the synchronization through software.

This feature enables all the BTSs under a BSC to synchronize with each other by

adjusting the frame number, timeslot, and bit offset to be the same through software.

In the asynchronous network, the system cannot estimate the adjacent-channel interference

but only can reduce the interference by using the functions such as loose frequency reuse and

frequency hopping.

In the synchronous network, the system estimates the co-channel and adjacent-channel

interference in any inter-cell overlapping area and minimizes inter-cell co-channel and

adjacent-channel collision by adopting the dynamic frequency allocation and dynamic

channel allocation. This greatly improves the frequency usage and increases the network

capacity.

In the synchronous network, the ICC and SAIC achieves the optimal performance. When

wanted signals are synchronized with interfering signals in time, the interfering signals are the

same in the entire burst. The interference estimated on the basis of the training sequence can

effectively counteract the interference during the burst. In this case, the ICC and SAIC

provide the optimal performance.

The Soft-Synchronized Network feature needs to be used together with the GBFD-117002

IBCA feature to avoid the inter-cell co-channel and adjacent-channel interference. This

greatly improves the frequency usage and increases the network capacity.

The Soft-Synchronized Network feature can be deployed at TDM network (including Abis IP

over E1/T1), while the IP network is not.

The Soft-Synchronized Network feature can only be used for Abis interface using TDM

transmission network (including Abis IP over E1/T1), cannot apply Abis interface using

Ethernet networking scene.




252

The Soft-Synchronized Network feature is applicable to the scenario where the end-to-end

communication between the BSC and BTS is based on TDM, such as Abis TDM over

E1/T1/STM-1 and Abis IP over E1/T1/STM-1. When the Ethernet network is used between

the BSC and BTS, that is, Abis IP over FE / GE, the Soft-Synchronized Network feature is not

supported.

Enhancement

GBSS8.1

Inter-BSC soft-synchronized network: software synchronization of BTSs under multiple

BSCs

Multiple-reference soft-synchronized network: In the system, some BTSs are synchronized

through hardware and others are synchronized through software to enable the flexible

networking. When the network replanning and upgrade are required, the enhanced feature

fully utilizes the existing resources to realize synchronization, reducing the workload of

synchronization and saving the costs.

Dependency


IP interface is needed to support Inter BSC Soft-Synchronized Network.





GBFD-118621 Connection Inter BSC over IP




In the network of using GBFD-118201 Soft-Synchronized Network or GPS for

synchronization, it is recommended working with the following features:

GBFD-115801 ICC

GBFD-115821 EICC



None

7.2.13 GBFD-510401 BTS GPS Synchronization

Availability





253

Summary

The BTS supports the GPS synchronization through a satellite.

Benefits


The frame synchronization on the Um interface in the entire network by using the GPS

provides high synchronization precision and easy implementation.

When the network works in synchronous mode, the features such as ICC and IBCA can

be used to increase the network capacity by more than 40%.

This feature improves the KPIs such as mean opinion score (MOS), paging success rate,

handover success rate, call drop rate, and traffic volume.

Description

In the existing GSM system, the BTSs work in asynchronous mode, resulting in timeslot

overlapping. In the asynchronous network with the tight frequency reuse pattern, the

overlapping of timeslots causes unnecessary and unpredictable interference because the

frequency reuse distance between two cells using the same frequency is relatively short. The

interference (that is, channel quality) rather than the number of channels restricts the network

performance. Therefore, the BTSs in the entire network synchronize with each other based on

the reference clock signals provided by the GPS satellite.

The GPS clock system of the BTS receives the related information sent by the GPS satellite

and then obtains the GPS absolute time and precise 1PPS pulse signals. The BTS clock circuit

traces the 1PPS pulse signals to obtain the reference clock and then obtains various clock

signals based on the reference clock. Each BTS in the network adjusts the frame number

based on the absolute frame number calculated from the GPS absolute time received by the

BTS software.

Enhancement

Each BTS is equipped with a GPS for hardware synchronization of the entire network, which

increases the costs. Therefore, the Soft-Synchronized Network feature, which is an optional

feature, is introduced to GBSS8.0 to realize the frame synchronization on the Um interface

through software. For details, see the GBFD-118201 Soft-Synchronized Network feature.

Dependency


None




None


None




254

7.2.14 GBFD-113706 Mega BSC

Availability


Summary

With this feature, a BSC supports a maximum of 8192 TRXs and 45,000 erlang of traffic

volume when IP over FE/GE is used over the A, Abis, and Gb interfaces.

Benefits


Enables a BSC to support more subscribers while maintaining the speech quality.

Improves the BSC equipment integration, which helps reduce the number of BSC nodes,

the footprint in the equipment room, and the power consumption per TRX.

Simplifies BSC parameter settings, which improves the network maintenance efficiency.

Reduces the number of inter-BSC handovers and cell reselections, which improves

network performance.

Description

With this feature, the improved specifications are as follows:

Item Specification

Number of TRXs 8192

Traffic volume 45,000 (erlang)

Busy hour call attempts (BHCAs)

for a CS+PS composite service

11,000,000

Number of users 2,200,000

Circuit identification codes (CICs)

on the A interface

61,440

Number of PDCHs that can be

activated

32,768

PS traffic throughput 3072 (Mbit/s)

1. If TDM over FE/GE is used over the A, Abis, and Gb interfaces, the TRX supporting

capacity remains unchanged, that is, a BSC supports a maximum of 4096 TRXs.

2. If both IP and TDM transmission modes are used, the maximum number of TRXs

supported by TDM-based BTSs is 4096, and the maximum number of TRXs supported

by the BSC is less than 8192, depending on the number of configured TRX boards.




255

3. The system specification (a maximum number of 2048 BTSs and 2048 cells) remains

unchanged.

Enhancement

None

Dependency


The BSC6900 must be configured with the following boards: DPUf, DPUg, XPUb, FG2c,

GOUc, SCUb, and OMUc. In addition, IP over FE/GE must be used over the A, Gb, and Abis

interfaces.


None


None


None

7.3 High Speed Mobility

7.3.1 GBFD-510101 Automatic Frequency Correction (AFC)

Availability


Summary

The automatic frequency correction (AFC) feature uses a special balancing algorithm to

estimate the difference between the standard frequency and the frequency of the

GMSK-coded signal sent from the fast-moving MS to the BTS. The AFC estimates the

frequency offset between the frequency of each received burst and the standard frequency in

real time. Then, the estimated frequency offset is used to correct the RX working frequency of

the BTS.

Benefits

This feature improves the decoding performance of the physical link in the uplink in the fast

moving condition, ensuring the physical transmission performance and reliable connections

between the fast-moving MS and the BTS. In addition, this feature enables the system to

support a telecommunication environment with a speed higher than 500 km/h, which serves

as the basis of the high-speed frequency offset handover algorithm.




256

Description

AFC is a BTS frequency correction algorithm designed for fast-moving MSs. This algorithm

ensures reliable radio links and continuous services with good voice quality when the MS

moves at a speed of 500 km/h.

According to Doppler frequency shift principle, the frequency of the signals sent by the

fast-moving MS shifts. The frequency shift information is related to the moving speed and

direction of the MS relative to the BTS. The BTS digital signal processor uses a special

balancing algorithm to estimate the difference between the standard frequency and the

frequency of the GMSK-coded signal sent from the fast-moving MS to the BTS. The AFC

estimates the frequency offset between the frequency of each received burst and the standard

frequency in real time. Then, the estimated frequency offset is used to correct the RX working

frequency of the BTS. This feature improves the decoding performance of the physical link in

the uplink in the fast moving condition, ensuring the physical transmission performance and

reliable connections between the fast-moving MS and the BTS.

The performance of AFC depends on the vertical distance between the BTS and the railway.

The shorter the vertical distance is, the faster the change of the frequency offset is when the

train approaches the BTS. Therefore, the AFC loop cannot keep pace with the change of

frequency offset, leading to a great residual frequency offset.

Simulation results show that the frequency offset smaller than 100 Hz has little impact on the

demodulation performance. Therefore, when the TRX is on the GSM900 band and the speed

of the train is 600 km/h, only the vertical distance of more than 100 m is supported if the loop

bandwidth is 2 Hz. In the case of a lower demand for the voice quality, the vertical distance

between the BTS and the railway can be shorter.

Enhancement

GBSS12.0

Common AFC corrects only uplink frequencies so that the BTS can correctly demodulate

uplink signals. The downlink signals from the BTS to the MS also encounter Doppler

frequency shift. Most MSs, however, do not have the frequency correction function.

The downlink AFC function enables the BTS to pre-compensate downlink signals for

frequency offset based on the estimated uplink frequency offset so that the frequency offset of

the downlink signals received by the MS is zero.

Dependency


None






GBFD-115821 EICC

GBFD-115830 VAMOS




257


None

7.3.2 GBFD-510102 Fast Move Handover

Availability


Summary

This feature enables better cell handover in a short period of time.

Benefits

Generally, the chain cell algorithm is not used because of the special characteristics of the

railway and highway users. This may lead to slow handover or call drops during handover.

With this feature, the handover success rate in the fast-moving condition is increased and

therefore the subscriber satisfaction is increased.

Description

In a fast-moving train, it takes a short time for an MS to move across a cell. Therefore, a

handover must be performed quickly. To reduce the handover failure rate, a handover must be

quickly initiated when required. If the handover fails (for example, when the radio interface

suddenly incurs interference), a second handover must be quickly initiated.

The fast PBGT handover algorithm enables better cell handover in a short period of time.

Compared with the existing PBGT handover algorithm, the fast PBGT handover algorithm

has the following advantages:

Handing over an MS to a proper target cell by predicting the moving direction of the MS

Accelerating the handover decision to improve the handover rate

Enhancement

None

Dependency


None





GBFD-510103 Chain Cell Handover





258

None

7.3.3 GBFD-510103 Chain Cell Handover

Availability


Summary

This feature enables the fast-moving MS to be preferentially handed over to the chain

neighboring cell.

Benefits

This feature increases the handover success rate in the fast-moving condition and therefore

increases the subscriber satisfaction.

Description

By predicting the moving direction of a fast-moving MS, this feature enables the fast-moving

MS to be handed over between two chain neighboring cells. Therefore, the handover success

rate is increased and the network quality is improved. Chain neighboring cells ensure reliable

handovers between cells.

Chain neighboring cells are formed on the basis of the linear coverage characteristic of

the fast-moving environment such as the railway.

A handover to a chain neighboring cell is preferred. In addition, handover to the moving

direction of the user should be guaranteed.

Enhancement

None

Dependency


None




None


None




259

7.3.4 GBFD-510104 Multi-site Cell

Availability


Summary

This feature enables the subsites in different physical sites to be set to a logical cell, which is

also called a cascading cell. A subsite refers to a certain area physically covered by multiple

RRU/RFUs that belong to the same BBU. In the scenarios such as railway, tunnel, or indoor

coverage, a cascading cell can reduce handovers, improve the coverage efficiency, and

enhance the user experience.

Benefits


This feature reduces handovers between cells and increases the handover success rate.

A cascading cell increases the effective coverage distance of each subsite and improves

the coverage efficiency of the entire cell because few handover areas are required

between different subsites.

Description

Cell cascading means that different subsites in the same BBU physically belong to different

sites but logically belong to the same cell. The principle is shown in the following figure.

Cascading cells are carried in multiple subsites. These subsites have the same cell parameters

such as physical configurations, the number of TRXs, and frequencies. One cascading cell has

only one primary subsite responsible for cell management and service control. Other subsites

are secondary subsites. Under the control of the primary subsite, these secondary subsites




260

implement cell service functions such as the selection of available TRXs and the activation of

channels.

During the initial access of an MS, all the subsites calculate the uplink signal noise ratio (SNR)

of the MS respectively and report the result to the primary subsite. Then the primary subsite

selects the subsite with the optimal SNR as the serving subsite.

All the subsites continuously calculate the uplink SNR of the MS and then report the SNR to

the primary subsite. When the SNR reported by an adjacent subsite is better than the SNR

reported by the serving subsite, the handover between subsites is triggered. When the MS is

handed over between subsites, the new subsite is connected and then the old subsite is

disconnected without the interruption of services. In this manner, seamless handover is

implemented and the QoS is guaranteed.

Enhancement

None

Dependency


None




This feature cannot be used with the following features:


GBFD-118201Soft-Synchronized Network


GBFD-115830 VAMOS

GBFD-111612 Multi-Carrier Intelligent Voltage Regulation

This feature cannot be used with the following features in GBSS12.0 and its earlier versions:




None

7.3.5 GBFD-510105 PS AFC

Availability





261

Summary

PS Automatic Frequency Control (AFC) applies to PS services that use Gaussian Minimum

Shift Keying (GMSK) or 8 Phase Shift Keying (8PSK) and are processed along high-speed

railways. PS AFC estimates the frequency offset for each burst by using frequency

discrimination. Based on the frequency offset, PS AFC corrects the frequency of baseband

signals before whitening filtering, and then the signals whose frequencies are corrected are

used for demodulation.

This feature improves the demodulation performance of uplink high-order PS services from

MSs that are moving at least 200 km/hour (GSM900) or at least 100 km/hour (DCS1800).

Applying this feature on services from MSs that are moving at a low rate of speed, however,

will deteriorate the demodulation performance.

Benefits


Improves the throughput of uplink Enhanced Data Rates for Global Evolution (EDGE)

services.

Decreases the demodulation threshold for uplink EDGE services.

Decreases the EDGE data block retransmission rate.

Description

PS AFC has three procedures: frequency discrimination, frequency correction, and time

resynchronization and channel estimation. The AFC process is described as follows:

1. PS AFC performs frequency discrimination on the IQ data of a burst before whitening

filtering as follows: After reconstructing reference receive signals based on the local training

sequence and the Channel Impulse Response (CIR), the PS AFC module performs the

correlation operation and cross product on the receive signals and the reference receive signal

to estimate the frequency offset. If the estimated frequency offset is less than or equal to 1000

Hz (GSM900)/2000 Hz (DCS1800), the estimated value is used. If the estimated frequency

offset is greater than 1000 Hz (GSM900)/2000 Hz (DCS1800), the value 1000 Hz

(GSM900)/2000 Hz (DCS1800) is used.

2. PS AFC corrects the frequency of the IQ data for this burst before whitening filtering.

3. PS AFC performs time resynchronization and Least Square (LS) channel estimation on the

IQ data after frequency correction. The length of the CIR used during time resynchronization

and LS channel estimation is calculated by the CIR length adaptive module.

If PS AFC is enabled, the IQ data and CIR after AFC are used. If PS AFC is disabled, the IQ

data and CIR before AFC are used.

If PS AFC is disabled, PS services using Modulation and Coding Scheme 5 (MCS5) are

unavailable for MSs moving faster than 350 km/hour because the demodulation performance

is poor. If PS AFC is enabled, PS services using MCS5 reach the peak throughput when the

Signal-to-Noise Ratio (SNR) is greater than 10 dB.

Applying PS AFC increases the throughput of PS services using MCS1 by 25% to 100% for

MSs moving 550 km/hour and with an SNR of 2 dB to 6 dB. The throughput of these PS

services is inversely proportional to the SNR.

The preceding moving speed applies to MSs that work at GSM900. The speed for MSs that work at GSM1800 is reduced by 50%.




262

Enhancement

None

Dependency


None





GBFD-115821 EICC


None

7.4 Intra-System Mobility Management

7.4.1 GBFD-510501 HUAWEI II Handover

Availability


Summary

HUAWEI II handover algorithm is optimized from HUAWEI I handover algorithm. HUAWEI

II handover algorithm takes all results of handover decisions into account, obtaining more

accurate results of handover decisions.

Benefits

This feature improves the accuracy of the handover decision and increases the handover

success rate.

This feature enhances the network quality and improves the network KPIs.

Description

HUAWEI II handover algorithm takes account all results of handover decisions and candidate

cell list, and then generates the handover execution policy.

HUAWEI II handover algorithm is categorized into three handover algorithms: emergency

handover (directed retry, frequency offset handover, bad quality handover, TA handover, and

edge handover), intra-cell handover (interference handover, BCCH tight frequency

multiplexing in concentric cell, AMR handover), inter-cell handover (better cell handover,

enhanced dual band network handover, fast-moving handover, and GSM-to-3G inter-RAT




263

handover). All handover decisions are traversed in the handover decision phase. Unlike

common handover algorithms, HUAWEI II handover algorithm is not performed immediately

if the triggering condition of a handover is met during the traverse. But only the candidate

target cell lists with handover decision type are generated independently. After all handover

decisions are traversed, HUAWEI II handover algorithm takes the intersection from the

candidate target cell lists corresponding to the handovers that meet the triggering condition,

and then generates the final target cell list for the handover. Compared with common

handover algorithms, HUAWEI II handover algorithm takes all results of handover decisions

into account, obtaining more accurate results of handover decisions.

Enhancement

GBSS14.0

A handover penalty inheritance mechanism is added to the load handover. When a load

handover is successful, the penalty cell list from the source cell is inherited and therefore

ping-pong handovers are prevented.

Dependency


None




None


None

7.4.2 GBFD-510502 Handover Re-establishment

Availability


Summary

On receiving the Error Indication message from the BTS during the handover process, the

BSC does not regard it as a call drop directly and attempts to re-establish a call on the old

channel.

Benefits

Handover re-establishment provides the following benefits:

Reduces the call drop rate and improving user satisfaction.

Improves network KPIs.




264

Description

In the handover process, the BSC sends the Handover Command message to the MS. Then, if

the BSC does not receive any response from the MS but receives an Error Indication message

from the BTS, the BSC regards it as a call drop. After handover re-establishment is applied,

the BSC indicates that the BTS can re-establish a call on the old link over the Um interface

after the BSC receives an Error Indication message on the old link. If the call re-establishment

is successful, the MS makes calls on the old channel and no call drop occurs.

Enhancement

None

Dependency


None




None



7.4.3 GBFD-117501 Enhanced Measurement Report (EMR)

Availability


Summary

The EMR is a new downlink measurement report introduced in R99. Compared with the

traditional MR, the EMR has more measurement-related information, such as the bit error

probability (BEP) and frame erase ratio (FER). This facilitates the performance improvement

of the power control algorithm and the handover algorithm.

Benefits


Improves the capability of monitoring the voice quality, and the performance of the

power control algorithm and the handover algorithm.

Provides better performance for GSM/WCDMA/TD-SCDMA interoperability by

supporting up to 15 neighboring 3G cells.




265

Description

The EMR is a new downlink measurement report introduced in R99. It is reported to the

network by the MS. Compared with the MR, the EMR has the following advantages:

1. The EMR uses an optimized scheme of encoding the neighboring cell information and

reports more neighboring cells than the MR. The MR provides up to six neighboring GSM

cells whereas the EMR provides up to 15 GSM/WCDMA/TD_SCDMA neighboring cells.

Therefore, the EMR provides better performance for the GSM/WCDMA/TD-SCDMA

interoperability and ensures the service continuity.

2. The EMR is added with the BEP, which is used to identify the channel quality. BEP is

estimated one burst after another. It reflects the current C/I, delay of signals, and velocity of

the MS. In addition, BEP adopts the 5-bit encoding scheme whereas RXQUAL adopts the

3-bit encoding scheme. Therefore, compared with RXQUAL, BEP has higher precision,

especially when the radio signal quality is poor.

3. The EMR is added with the number of speech frames that are correctly received, which is

used to calculate FER. In comparison with RXQUAL that measures the radio signal, the

measurement effect of EFR is better because it measures the encoding/decoding performance

of the speech signal.

RXQUAL should be replaced with BEP and FER for the power control algorithm and the

handover algorithm that use RXQUAL to evaluate radio signal quality because BEP and FER

can be used to improve the performance of those algorithms.

According to 3GPP TS 44018, through the MI/2QUATER system information, the network

can determine whether an MS should report the measurement information about the serving

cell and neighboring cells through MR or EMR.

This feature should be supported by MS. If EMR enabled, and MS cannot report accurately

measurement items of EMR, like BEP and FER, the HO success rate may be dropped.

Enhancement

None

Dependency


None




None






266

7.4.4 GBFD-117101 BTS Power Lift for Handover

Availability


Summary

Before sending the handover command to the MS, the BSC adjusts the transmit power of the

BTS to the maximum value to prevent call drops due to rapid level drop.

Benefits


Reduces call drops, increases handover success rate, and optimizes KPIs.

Improves voice quality, prolongs call duration, and increases the operators' revenue.

Description

During the call, if the receive level drops rapidly, the handover is triggered to avoid call drops.

The power control algorithm, however, may fail to adjust the MS and BTS power in time.

Therefore, the MS fails to receive the handover command, which then causes call drops.

Using the BTS power lift for handover feature, the BSC can adjust the transmit power of the

BTS to the maximum value before sending the handover command to the MS to prevent call

drops due to rapid level drop.

Enhancement

None

Dependency


None




None


None




267

7.5 GSM & WCDMA Interoperability

7.5.1 GBFD-114301 GSM/WCDMA Interoperability

Availability


Summary

The BSS system supports the handover and reselection of MSs between the GSM network

and the WCDMA network.

Benefits

This feature enables the MS to roam and be handed over from the WCDMA network to the

GSM network. This can solve the problem of insufficient coverage in the early stage of the

WCDMA network development. With this feature, the GSM network can smoothly evolve to

the WCDMA network, saving the operator's investment.

Description

GSM/WCDMA interoperability refers to the handover and roaming of dual-mode MSs

between the GSM network and the WCDMA network. Huawei BSS supports the handover

and roaming of dual-mode MSs between the GSM network and the WCDMA network. The

handover and roaming include the following situations:

In idle mode, an MS roams from the GSM system to the WCDMA system.

In idle mode, an MS roams from the WCDMA system to the GSM system.

In busy mode, an MS is handed over from the GSM system to the WCDMA system.

In busy mode, an MS is handed over from the WCDMA system to the GSM system.

This feature consists of the following functions:

Roaming in idle mode

Through PLMN reselection, an MS can be handed over from the GSM network to the

WCDMA network, or from the WCDMA network to the GSM network. The selection of

the GSM network or the WCDMA network is determined by the network operator.

Usually the WCDMA MSs preferentially select the WCDMA network. The PLMN

reselection can be scheduled on the MS. The reselection time is determined by the

operator.

To inform the MS of the information on the WCDMA neighboring cell, the GBSS

system needs to add the description of the WCDMA neighboring cell to the system

information. The system information 3 is modified to indicate whether the system

information 2 quarter exists. The system information 2 quarter includes information

about cell reselection, measurement, and WCDMA neighboring cell.

Through system reselection, a WCDMA MS can be handed over to a neighboring GSM

cell when the signal in the WCDMA network is weak.

CS domain handover in busy mode




268

The handover from the WCDMA system to the GSM system is determined by the

WCDMA network. When receiving the handover request from the MSC, the BSS works

with the MSC to implement the handover based on the resource situation.

Then, the MS in busy mode in the GSM cell measures the WCDMA neighboring cell

based on the neighboring cell information in the system information and submits the

measurement report to the BSC. The BSC then makes decisions according to the

information in the measurement report and initiates inter-RAT handover when the

requirements for the WCDMA cell handover are met.

The cell reselection of the network-controlled MS from the GPRS/EDGE system to the

WCDMA system is implemented by using the inter-RAT NC2 feature. The inter-RAT

NACC feature can speed up the cell reselection from the WCDMA system to the

GPRS/EDGE system.

Enhancement

None

Dependency


None




None


The MS, MSC, SGSN, HLR, and the WCDMA-related NEs must support this feature.

7.5.2 GBFD-114321 GSM/WCDMA Service Based Handover

Availability


Summary

In a GSM-WCDMA co-sited network, the operator can classify services into different types

according to the operation policies. Then, the operator determines whether a service

preferentially uses the radio resources of the GSM system or the WCDMA system. During

call access or the handover, the BSC works with the MSC to perform the handover from the

GSM system to the WCDMA system.

Benefits

With this feature, the advantages of the GSM system and the WCDMA system are fully

utilized and therefore the service quality is improved and the user experience is enhanced. In




269

addition, the operators' investment is saved and the utilization of the network resources is

maximized.

Description

With the application of the WCDMA system, the GSM-WCDMA co-sited network is widely

in use. The service quality on the two radio access systems is different. Therefore, it is

necessary to immediately use different system resources for different services. According to

the service hierarchy principle, different services can be preferentially handed over to

different systems. For example, the CS services are preferentially handed over to the GSM

system whereas the PS services are preferentially retained in the WCDMA system.

In the assignment procedure, the MSC sends the service handover information to the BSC

through the ASSIGNMENT REQUEST message. If the service handover information

indicates that the call should be preferentially processed in the UTRAN, the directed retry

procedure is initiated to hand over the call to the WCDMA system.

The HANDOVER REQUEST message received by the BSC may also carry the service

handover information and the BSC uses this information for the subsequent handover

decision.

Enhancement

None

Dependency


None





GBFD-114301 GSM/WCDMA Interoperability


The MS, MSC, SGSN, HLR, and WCDMA-related NEs must support this feature.

7.5.3 GBFD-114322 GSM/WCDMA Load Based Handover

Availability


Summary

When the cell load in the GSM system is heavy, the BSC can initiate the handover from the

GSM system to the WCDMA system based on the load of the GSM system and the WCDMA

system to balance the overall load in the network, maximizing the utilization of the network

resources.




270

Benefits

This feature balances the load of the WCDMA system and the GSM system, improving the

service quality and the usage of the network resources.

Description

With the application of the WCDMA system, the GSM-WCDMA co-sited network is widely

in use. Therefore, the usage of the resources in the two radio access systems needs to be

maximized. When the load of one radio access system is heavy whereas the load of the other

radio access system with the same coverage is light, the load-based inter-RAT handover can

be initiated to balance the load of the two systems if the services of the current user can be

supported by the other system.

The load information about the WCDMA system is transparently transmitted to the BSC

through the MSC. Then the BSC determines whether to initiate the inter-RAT handover based

on the load information about the WCDMA system and the load information about the BSC.

Meanwhile, the load information about the BSC is carried in the handover request message

for the reference of the target system during the inter-RAT handover decision.

Enhancement

None

Dependency


None





GBFD-114301 GSM/WCDMA Interoperability


The MS, MSC, SGSN, HLR, and WCDMA-related NEs must support this feature.

7.5.4 GBFD-114323 GSM/WCDMA Cell Reselection Based on MS State

Availability


Summary

This feature is designed to optimize cell reselection from the GSM network to the 3G network

(WCDMA network or TD-SCDMA network). It enables dual-mode MSs in the idle state or in




271

the packet transfer state to adopt different reselection policies to access the GSM network or

3G network as required.

Benefits


Helps the operator to determine whether to select the GSM or 3G network according to

the network planning requirements when the MS is in the idle state or in the packet

transfer state.

Reduces the duration of service interruption caused by frequent cell reselection.

Description

During the 3G network construction, operators need to select a proper network planning

strategy for the MSs to select the GSM network or the 3G network based on the coverage of

the 3G network and the compatibility of dual-mode MSs with the 3G network. This feature

provides different cell reselection strategies based on the MS state.

For example, in the early stage of the 3G network construction, operators expect that the 3G

network can share some traffic of the GSM network. The data transmission of the MS in

packet transfer mode, however, may be interrupted after cell reselection because the coverage

of the 3G network is imperfect or the compatibility between the MS and 3G network is poor.

In such a case, the KPIs deteriorate. In addition, the current 3GPP protocols do not support the

NACC feature between the GERAN and the UTRAN. Therefore, the services of the MS in

packet transfer state are inevitably interrupted during the inter-RAT cell reselection and

therefore the quality of the PS services deteriorates. With this feature, operators allow the MS

in idle mode to search for neighboring 3G cells by setting the parameter Qsearch_I to a

specific value between 0 and 14. Similarly, operators can prohibit the MS in packet transfer

mode to search for neighboring 3G cells by setting the parameter Qsearch_P to 15. In this

manner, operators can control the MS's access to the GSM network or the 3G network

according to the MS state.

This feature and the Network-Controlled Cell Reselection (NC2) feature are mutually

exclusive. With the NC2 feature, the MS in packet transfer state can select a neighboring 3G

cell through the BSC's control of the inter-RAT cell reselection. With this feature, however,

the MS in packet transfer state can be prohibited from selecting a neighboring 3G cell. This

problem can be solved by configuring priorities for these two features.

Enhancement

None

Dependency


None








272

GBFD-114301 GSM/WCDMA Interoperability or

GBFD-114302 GSM/TD-SCDMA Interoperability



7.5.5 GBFD-114325 Fast WCDMA Reselection at 2G CS Call Release

Availability


Summary

When an MS terminates a call in the GSM network, it camps on the WCDMA network

according to the cell selection indicator after release information in the Channel Release

message instead of cell reselection from GSM to WCDMA.

Benefits

The cell reselection of the MS is accelerated. The MS can obtain services from the WCDMA

network immediately after the call is released from the GSM network.

Description

In general, when the MS terminates a call in the GSM network, it camps on the cell in which

the call is released and then starts the measurement related to the cell reselection. When a

WCDMA neighboring cell meets the requirements for cell reselection, the MS camps on the

WCDMA network after the cell reselection. The WCDMA cell reselection is initiated after the

MS receives the system information and performs the related calculation. In this case, the

time for the MS to access the WCDMA network is prolonged.

When this feature is enabled, the BSS figures out the best WCDMA neighboring cell based on

the measurement information on the WCDMA neighboring cells after the MS in the GSM

network terminates a CS call. Then, the BSS sends the MS the frequency information on the

cell through the Channel Release message to instruct it to camp on the WCDMA cell. In this

way, the MS can camp on a WCDMA cell without related calculation, accelerating cell

reselection

Enhancement

None

Dependency


None






273


None



7.5.6 GBFD-511101 Load Based Handover Enhancement on Iur-g

Availability


Summary

This feature is implemented through the exchange of Huawei proprietary IE containing load

information over the Iur-g interface. The Iur-g protocol stack complies with the 3GPP

specifications. With this feature, the decision on handover that is not caused by insufficient

coverage can be more accurate, reducing the possibility of ping-pong handovers between the

GSM network and WCDMA network.

Benefits

This feature helps maintain a load balance between the GSM network and WCDMA network.

It also helps increase the accuracy of handover decision, reducing the possibility of ping-pong

handovers. The simulation results show that this feature reduces the percentage of invalid

handovers between the GSM network and WCDMA network by up to 6 % and increases the

total capacity of the GSM network and WCDMA network by up to 5%.

Description

This feature functions as a supplement to GBFD-114322 GSM/WCDMA Load Based

Handover. If the handover decision is based only on load, the occurrence of ping-pong

handover is highly possible. The reason is that the mechanism of load information exchange

between the GSM network and WCDMA network is inadequate. The inadequate mechanism

may cause excessive services to be handed over from the GSM network to the WCDMA

network, leading to the overload of the WCDMA network and consequently handover back to

the GSM network.

This feature enables the load information exchange over the Iur-g interface, so that the

decision on load-based handover can be more rational. The conditions on which the decision

is based are as follows:

The target WCDMA cell meets the load requirements.

The load difference between the source GSM cell and target WCDMA cell exceeds the

predefined threshold.

The handover will not lead to the congestion in the target WCDMA cell.

Enhancement

None




274

Dependency

Dependency on MBSC hardware

The Iur-g interface can be configured only on the FG2a/FG2c/GOUa/GOUc board.

Dependency on MBTS hardware




GBFD-114322 GSM/WCDMA Load Based Handover

WRFD-070004 Load Based GSM and WCDMA Handover Enhancement Based on Iur-g


None

7.5.7 GBFD-511102 NACC Procedure Optimization Based on Iur-g between GSM and WCDMA

Availability


Summary

This feature enables the exchange of messages containing the RAN Information Management

(RIM) information over the Iur-g interface between the RNC and BSC. The Iur-g protocol

stack complies with the 3GPP specifications. In this way, the NACC procedure for PS

services from a WCDMA cell to a GSM cell does not require the information transfer via the

CN.

Benefits

This feature provides a solution that enables the NACC procedure when the CN does not

support the RIM procedure. The simulation results show that this feature helps shorten the

delay of PS handover by two seconds. As the delay is shortened, the user experience can be

improved.

Description

As indicated in the 3GPP specifications, the GERAN (P) SI is obtained through the RIM

procedure during the NACC procedure. The NACC procedure involves the RNC, WCDMA

SGSN, GSM SGSN, and BSC. When this feature is applied, the GSM/WCDMA GERAN (P)

SI information is transferred over the Iur-g interface between the base station controllers,

without being transferred via the CN.

This feature applies only to the Iur-g interface, which connects different base station

controllers. In such a case, the GERAN (P) SI information is transferred over the protocol

stack complying with the 3GPP specifications. If there is no Iur-g interface between WCDMA

and GSM, the GERAN (P) SI information can be exchanged only via the CN, and accordingly




275

the NACC procedure can be implemented only through the CN, as specified in the 3GPP

specifications.

The following figure shows the network topology that supports this feature. As shown in the

figure, Huawei RNCs and BSCs are connected through the Iur-g interface. This feature

applies to the BSC/RNC of other vendors only if it has passed the interoperability test (IOT).

Otherwise, the CN-involved NACC procedure is applied. For the BSC/RNC of other vendors,

the common cell reselection procedure is performed if the CN does not support the RIM

procedure.

Enhancement

None

Dependency







WRFD-070005 NACC Procedure Optimization Based on Iur-g between GSM and WCDMA.


The NACC procedure must be supported by the MS/UE.




276

7.5.8 GBFD-511103 GSM and WCDMA Load Balancing Based on Iur-g

Availability


Summary

This feature implements the load-based GSM/WCDMA handover through the exchange of

Huawei proprietary IE over the Iur-g interface. With this feature, the traffic is distributed on

the basis of the service handover indicator and load of the GSM network and WCDMA

network when an MS accesses the network. In this way, a load balance is achieved between

the GSM network and WCDMA network.

Benefits

This feature aims at striking a load balance between the GSM network and WCDMA network.

It reduces the possibility of congestion in areas covered by both GSM and WCDMA. The

network utilization is consequently increased. The simulation results show that this feature

reduces the percentage of invalid handovers between the GSM network and WCDMA

network by up to 6 % and decreases the access congestion rate during busy hours by up to

4%.

Description

As high-speed PS services are on great demand by a large number of GSM/WCDMA

dual-mode handsets in well-established 2G/3G commercial networks, the load of WCDMA

network has become increasingly heavy. Facing the situation, network operators focus on

reducing the congestion rate and making full utilization of the present network capacity. This

feature can efficiently address this issue. With this feature, the load balance between the GSM

network and WCDMA network can be achieved. This helps reduce the possibility of network

congestion and the percentage of invalid inter-RAT handovers. As a result, the capacity of

both the GSM network and WCDMA network can be fully utilized.

The following figure shows the applicable scenario where the GSM cell and WCDMA cell

have the same coverage. In this scenario, this feature provides a load-balancing function for

admitted MSs through the exchange of Huawei proprietary IE between the GSM cell and

WCDMA cell.




277

The load-balancing function is initiated after RAB setup. The GBSC/MBSC decides whether

to hand over the requested CS service to the WCDMA network on the basis of the service

handover indicator and the load difference between the GSM cell and the target WCDMA cell.

The conditions on which the decision is based are as follows:

The MS supports WCDMA services.

The service handover indicator assigned by the CN or configured at the GBSC/MBSC

shows that the CS service can be handed over to the WCDMA cell.

The target WCDMA cell is lightly loaded.

The load difference between the source GSM cell and target WCDMA cell exceeds the

predefined threshold.

The GBSC/MBSC determines whether to perform the inter-RAT handover on a number

of MSs according to the predefined distribution rate. The rate is considered as a

probability rate with respect to the redirection of a single MS. If the GBSC/MBSC

determines that the handover is not performed, the CS service will be processed in the

GSM cell.

This feature in the present version (GBSS12.0) applies to only the handover of CS services

from a GSM cell to a WCDMA cell.

Enhancement

None

Dependency








278



GBFD-114322 GSM and WCDMA Load Based Handover

WRFD-070006 GSM and WCDMA Load Balancing Based on Iur-g


None

7.5.9 GBFD-511104 GSM and WCDMA Traffic Steering Based on Iur-g

Availability


Summary

This feature supports GSM/WCDMA handover based on service. With this feature, services

are steered on the basis of the service handover indicator, hierarchical network planning, and

the load of the GSM network and WCDMA network when an MS accesses the network.

Benefits

This feature helps operators to develop network services in hierarchies, which facilitates the

hierarchical network planning. With this feature, the spectrum utilization is increased. The

simulation results show that this feature reduces the percentage of invalid inter-RAT

handovers by up to 8% and increases the total capacity of the GSM network and WCDMA

network by up to 8%.

Description

In the case of evolution from a legacy GSM network to a GSM&WCDMA network, the

WCDMA network usually has a larger capacity in the early stage. How to fully utilize the

WCDMA network to carry high-speed services has become a major concern for network

operators. This feature provides the service steering function for the benefit of network

planning. Service steering helps improve the utilization of resources in each network and

divide frequencies and RATs into different hierarchies. In addition to service steering, the

selection of RAT for an MS to access also depends on the network load. This helps optimize

the network performance in the following aspects:

Tasks of different RATs can be clearly defined, which facilitates the planning of network

capacity.

Service steering can reduce interference between different traffic classes, increasing the

network capacity of the WCDMA network.

The flexible distribution of services to the WCDMA and GSM cells can improve the

utilization of system resources, reduce the access congestion rate, and enhance the QoS

of the network.

The service-steering function is initiated after RAB setup. The GBSC/MBSC decides whether

to hand over the MS to the WCDMA network on the basis of the service handover indicator




279

and the load difference between the GSM cell and the target WCDMA cell. The conditions on

which the decision is based are as follows:

The MS requests the CS service.

The MS supports WCDMA services.

The target WCDMA cell is lightly loaded and is with the lightest load among all

neighboring WCDMA cells of the source GSM cell.

This feature in the present version (GBSS12.0) applies to only the steering of CS services

from a GSM cell to a WCDMA cell.

Enhancement

None

Dependency







GBFD-114321 GSM/WCDMA Service Based Handover

WRFD-070007 GSM and WCDMA Traffic Steering Based on Iur-g


None

7.6 GSM & LTE Interoperability

7.6.1 GBFD-511301 Cell Reselection Between GSM and LTE

Availability

This feature was introduced in GBSS12.0 for test. It is commercially used from GBSS13.0.

Summary

This feature enables the GSM/LTE dual-mode MS in idle mode to perform cell reselection

based on the level of the neighboring cells and setting of the radio access technology (RAT)

priority.




280

Benefits This feature enables the GSM network and LTE network to work as a complement to

each other. This is profitable for operators who have deployed both the GSM network

and LTE network.

This feature enables the existing GSM network to provide communication services to

LTE subscribers at the initial deployment stage of LTE, generating profit for the LTE

operators.

This feature can be used to balance the traffic between the GSM network and LTE

network, prolonging the lifecycle of the GSM network.

A GSM/LTE dual-mode MS can be made to camp on the LTE network through the

setting of the RAT priority when the GSM/LTE dual-mode MS is within the coverage

area of the LTE network.

Description

An MS in idle mode periodically measures the level of the serving cell and the cell of the

neighboring cells specified in the system information. The MS determines whether to perform

cell reselection based on the settings of the mode priority parameters and on the cell

reselection algorithm. In this way, the MS can always camp on a cell that can provide quality

services. Therefore, the purpose of this feature is to bind the MS to a cell that can provide

quality services.

The cell reselection between GSM and LTE is based on the setting of the RAT priority. The

RAT priority is set on the BSC side, and is sent to the MS through the system information

message SI2quater. Different RAT priorities must be set for the GSM and LTE networks.

Therefore, the MS can select to camp on the network of higher service quality based on the

RAT priorities.

The MS obtains the information about the frequencies of the neighboring cells by parsing the

system information message SI2quater. It also measures the downlink level of all neighboring

cells to obtain the candidate cells for reselection. Then, the MS sorts the candidate cells

according to the RAT priority, and selects the best cell for reselection.

This feature supports the cell reselection between GSM and LTE FDD and the cell reselection

between GSM and LTE TDD.

Enhancement

None

Dependency


None





GBFD-511312 Fast LTE Reselection at 2G CS Call Release




281

GBFD-511313 CSFB


The Core network must support both GSM and LTE.

The MS must support both GSM and LTE.

7.6.2 GBFD-511302 PS Handover Between GSM and LTE Based on Coverage

Availability

This feature is available for beta use from GBSS12.0. It is available for commercial use from

GBSS13.0.

Summary

MSs in PS connection report MRs to the BSC periodically. The BSC obtains the receive level

of the serving cell through MRs. When the receive level of the serving cell remains lower

than the specified PS handover threshold for a period, the BSC triggers the PS handover

between GSM and LTE. In this manner, the MS reselects a neighboring cell with a higher

receive level.

Benefits

PS handover shortens the duration of the PS service disruption to no more than 150 ms

theoretically and provides guaranteed QoS for PS services, especially conversational services.

Therefore, the operators can deploy more value-added services such as VoIP, PoC, and

Gaming.

This feature provides PS coverage for cells of another RAT to ensure the PS service continuity.

In this manner, the network performance and user experience are improved.

Description

Conversational services have a high requirement for the service delay, which cannot be met

through cell reselection. In view of this, Huawei introduces the PS handover, during which

radio resources are allocated to the target cell before the cell change. In this manner, the

service disruption during cell change is reduced to less than 150 ms.

Based on the MRs reported by the MS, the BSC triggers the coverage-based PS handover

between GSM and LTE when the receive level of the serving cell remains lower than the PS

handover threshold for a period. This ensures that the MS can reselect a neighboring cell with

a higher receive level. As the receive level of the neighboring cell is considered before the

handover, the success rate of the handover, the throughput of the new cell, and the PS QoS

can be guaranteed.

Enhancement

GBSS13.0

The Fast PS Handover between GSM and LTE function is introduced.




282

If GSM cells and LTE cells are co-sited and cover the same areas, blind handovers must be

supported. When a GSM/LTE dual-mode or multi-mode MS is processing PS services in a

GSM cell, a service-based or load-based PS handover can be triggered to hand over the MS to

an LTE cell. In this case, a target LTE cell can be selected according to the default system

setting, without using the measurement reports (MRs).

Dependency


None





GBFD-511301 Cell Reselection Between GSM and LTE

GBFD-119502 PS Handover

PS handover priority:

GBFD-511306 GSM/LTE Service Based PS Handover >

GBFD-511303 PS Handover Between GSM and LTE Based on Quality >

GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load >

GBFD-511302 PS Handover Between GSM and LTE Based on Coverage

It is recommended the 4 features working together.



The SGSN must support PS handover between GSM and LTE.

7.6.3 GBFD-511303 PS Handover Between GSM and LTE Based on Quality

Availability


GBSS13.0.

Summary

MSs in PS connection report MRs to the BSC periodically. Based on the MRs, the BSC

triggers a PS handover to a neighboring LTE cell if the UL or DL signal quality in the current

GSM cell on the air interface reaches the specified threshold.




283

Benefits

PS handover shortens the duration of the PS service disruption to no more than 150 ms

theoretically and provides guaranteed QoS for PS services, especially conversational services.


Gaming.

In the scenarios with severe signal attenuation, this feature can be used to prevent PS service

disruption due to deterioration of signal quality on the air interface, improving network

performance and user experience.

Description

Conversational services have a high requirement for the service delay, which cannot be met

through cell reselection. In view of this, Huawei introduces the PS handover, during which

radio resources are allocated to the target cell before the cell change. In this manner, the

service disruption during cell change is reduced to less than 150 ms.

When the UL or DL air interface quality of the MS in the serving cell is reaches the preset

threshold, the BSC triggers the PS handover between GSM and LTE so that the MS reselects

an LTE neighboring cell with the highest receive level. In this manner, the success rate of the

PS handover, the throughput of the new cell, and the PS QoS are guaranteed.

Enhancement

GBSS13.0







Dependency


None













284







7.6.4 GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load

Availability


GBSS13.0.

Summary

Based on the traffic load and the MRs reported by the MS in PS connection mode, the BSC

may trigger the PS handover from GSM to LTE when the PS load on the GSM cell is high to

achieve load balance and in addition, to fully utilize the transmission resources.

Benefits

PS handover shortens the duration of the PS service disruption to no more than 150 ms and

provides guaranteed QoS for PS services, especially the conversational service. Therefore, the

operators can deploy more value-added services such as VoIP, PoC, and Gaming.

When the GSM network is congested, this feature can be used to transfer part of the load of

the GSM cell to the neighboring LTE cells, increasing the PS service rate and enhancing the

network performance and user experience.

Description

With the construction of the LTE network, the networking with both GSM and LTE is widely

used. Huawei aims to fully utilize the resources of the two networks. The LTE network can

take over part of PS services from the GSM network.

In an area covered with both GSM and LTE networks, if the load difference between the two

networks is great and the current services are supported by both GSM and LTE, the PS

handover between GSM and LTE can be triggered for load balance.

When this feature is enabled, the BSC selects an LTE neighboring cell with the highest

receive level for the handover. In this manner, the success rate of the PS handover, the

throughput of the new cell, and the PS QoS are guaranteed.

Enhancement

GBSS13.0




285


Conversational services have a high requirement for service interruption duration, which

cannot be met by using cell reselection. The PS handover technique, however, solves this

problem. During a PS handover, radio resources are allocated to the target cell before the MS

camps on the target cell. In this manner, the service interruption duration is reduced to less

than 150 ms.






Dependency


None
















7.6.5 GBFD-511305 PS Handover Between GSM and LTE Based on Mode Priority

Availability


GBSS13.0.




286

Summary

This feature enables operators to set priorities for GSM and LTE networks. In this manner,

during the PS handover, the MS will select a network with the higher priority.

Benefits

PS handover shortens the duration of the PS service disruption to no more than 150 ms and

provides guaranteed QoS for PS services, especially the conversational service. Therefore, the

operators can deploy more value-added services such as VoIP, PoC, and Gaming.

The operator can use the LTE network to carry PS services preferentially. That is, in the area

with LTE coverage, use the LTE network to provide high-speed data services for GSM/LTE

dual-mode users; in the area without LTE coverage, use the GSM network to carry the

services. In this manner, the operator can make profit quickly from the LET network and the

user experience is enhanced.

Description

In a network with both GSM and LTE coverage, this feature enables the GSM/LTE dual-mode

MSs to select LTE network preferentially for PS services.

Based on MRs from the MS, the BSC triggers a PS handover when the downlink level of the

serving cell reaches the level threshold for PS handover, when the UL or DL air interface

quality decreases to the handover threshold, or when the PS load of the GSM cell is high. The

BSC selects the cell with the highest receive level from the cells in a network with the highest

priority as the target cell.

Because the receive level, service quality, load, and network mode of the target cell and the

suitable network is considered before the PS handover, the handover success rate and the

throughput of the target cell are guaranteed.

This feature must be used together with the feature GBFD-511302 PS Handover Between

GSM and LTE Based on Coverage, GBFD-511303 PS Handover Between GSM and LTE

Based on Quality, or GBFD-511304 PS Handover Between GSM and LTE Based on Cell

Load.

Enhancement

None

Dependency


None




Depend on:


GBFD-511302 PS Handover Between GSM and LTE Based on Coverage or




287

GBFD-511303 PS Handover Between GSM and LTE Based on Quality or

GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load





7.6.6 GBFD-511306 GSM/LTE Service Based PS Handover

Availability


GBSS13.0.

Summary

In a network with both GSM and LTE coverage, the BSC hands over services of different

types to the GSM or LTE network based on the service distribution information sent by the

SGSN.

Benefits PS handover shortens the duration of the PS service disruption to no more than 150 ms

and provides guaranteed QoS for PS services, especially the conversational service.


Gaming.

The services of different types are handed over to the GSM or LTE network based on the

service attribute. In this manner, the loads on the two networks are balanced. In addition,

the PS services will not be handed over to an inappropriate network.

The operator can use the LET network to carry the services with high requirement for

rate and delay, enhancing user experience and increasing the revenue.

Description

In a network with both GSM and LTE coverage, the operator can divide the services into

multiple types, and then determine the network (GSM or LTE) for carrying each type of

services. In this manner, the load is balanced between the two networks, and the operator can

use the advantages of both GSM and LTE to provide satisfactory service quality.

For example, the operator can use the LTE network to carry the streaming services with a high

requirement for rate and the conversational services with a high requirement for delay, and

use the GSM network to carry the background services with a low requirement for rate and

delay.

The operator can configure the policy on the core network, and then during the PS handover,

the BSC hands over the services with different types to the corresponding network according

to the service distribution information sent by the core network.

According to 3GPP 48.018, the PS HANDOVER REQUEST message or the CREATE BSS

PFC message from the SGSN contains the IE that indicates the service type. If the IE is

"Network initiated cell change order to E-UTRAN or PS handover to E-UTRAN procedure




288

should be performed", the handover to an LTE cell is preferred. In this case, the BSC selects

an LTE neighboring cell with the highest receive level as the target cell, and then informs the

MS to hand over to the target cell through PS handover.

Enhancement

GBSS13.0


Conversational services have a high requirement for service interruption duration, which

cannot be met by using cell reselection. The PS handover technique, however, solves this

problem. During a PS handover, radio resources are allocated to the target cell before the MS

camps on the target cell. In this manner, the service interruption duration is reduced to less

than 150 ms.






Dependency


None



















289

7.6.7 GBFD-511307 eNC2 Between GSM and LTE

Availability


Summary

In a GSM/LTE hybrid network, when the MS is in a GSM cell, the MS periodically sends

packet measurement reports to the BSC if the serving cell is in NC2 mode and packet

connection state. On receiving the reports from the MS, the BSC triggers a

network-controlled cell reselection based on the receive level, cell load, receive quality,

modulation scheme, and service priority indicated by the message sent from the core network.

If the target cell is an LTE cell, the BSC triggers a procedure of eNC2 between GSM and

LTE.

Benefits

Compared with the MS-controlled cell reselection, eNC2 Between GSM and LTE has the

following benefits:

The following factors are considered at the network so that the MS can be reselected to a cell

with better signal quality: receive level of the serving cell, receive quality over the Um

interface, and packet service load, priority of modulation scheme, and service priority

indicated by the message sent from the core network. This can prevent deterioration of QoS of

the MS. In this manner, the user experience can be improved, for the duration of packet

service disruption is shortened to less than 500 ms.

Description

Four types of cell reselection decision are involved in eNC2 between GSM and LTE:

service-based cell reselection decision, quality-based cell reselection decision, load-based cell

reselection decision, and coverage-based cell.

1) Service-based cell reselection decision

According to 3GPP 48.018, the PS HANDOVER REQUEST message or the CREATE BSS

PFC message from the SGSN contains the IE that indicates the service type. If the IE is

"Network initiated cell change order to E-UTRAN or PS handover to E-UTRAN procedure

should be performed", the reselection to an LTE cell is preferred. In this case, the BSC selects

an LTE neighboring cell with the highest receive level as the target cell, and then informs the

MS to reselect the target cell through an eNC2 procedure.

2) Quality-based cell reselection decision

The BSC determines whether the radio link quality is good or bad according to the receive

quality or bit error rate, and performs a cell reselection decision based on the receive quality

of the link over the Um interface. When the receive quality of the uplink or downlink radio

link deteriorates to a specified threshold, the BSC triggers the NC2 procedure. The BSC

selects the cell with the highest receive level from the cells in a network with the highest

priority as the target cell.

3) Load-based cell reselection decision

The BSC performs a cell reselection decision based on the packet load of the serving cell.

When the packet load of the serving cell reaches a specified threshold, the BSC triggers the




290

NC2 procedure. The BSC selects the cell with the highest receive level from the cells in a

network with the highest priority as the target cell.

4) Coverage-based cell reselection decision

The BSC performs a cell reselection decision based on the receive level of the serving cell.

When the receive level of the serving cell is lower than a specified threshold for a period, the

BSC triggers the NC2 procedure. The BSC selects the cell with the highest receive level from

the cells in a network with the highest priority as the target cell.

Enhancement

None

Dependency


None






GBFD-119107 Networking Control Mode


The MS must support both GSM and LTE and NC2 procedure.

7.6.8 GBFD-511308 eNACC Between GSM and LTE

Availability


Summary

This feature supports eNACC from LTE to GSM only.

In packet transfer mode, the UE sends the eNodeB a message, requesting for the system

information of the target GSM cell. Upon receiving the message, the eNodeB sends the

system information of the target GSM cell to the UE. Upon receiving the system information,

the UE accelerates the packet service access to the target GSM cell.

Benefits The cell reselection of the UE from an LTE cell to a GSM cell is accelerated, the data

transmission disruption becomes shorter, and the duration of the service disruption is

shorter than 500 ms. In this manner, the requirements of services, such as streaming

service, for delay and throughput are met.




291

The resources of the original cell can be released for new subscribers faster after the cell

reselection. In this manner, the system capacity is increased.

Description

eNACC is a function based on which the UE accesses the target GSM cell quickly after the

cell reselection is completed without receiving the complete system information of the target

cell.

eNACC does not control cell reselection of the UE. Instead, the network is informed of the

message that the UE requires cell reselection, and then the network sends the system

information of target GSM cells to the UE before the cell reselection. In this manner, the cell

reselection is accelerated, and therefore the duration of data transmission disruption is

reduced greatly.

As the cell reselection is accelerated, the SGSN can detect faster that a new cell is reselected

for the UE. Therefore, the resources of the source LTE cell can be released faster for other

subscribers. In this manner, the system capacity is increased.

Limited by 3GPP 48.018 technical specifications, the system does not support GSM-to-LTE

eNACC. LTE-to-GSM eNACC is supported only when the BSC supports RIM over the Gb

interface.

Enhancement

None

Dependency


None





GBFD-116301 Network Assisted Cell Change (NACC)


The MS must support both GSM and LTE and NACC procedure.

The SGSN must support eNACC procedure.

7.6.9 GBFD-511309 SRVCC

Availability

This feature was introduced in GBSS12.0. This feature is recommended for test purposes

rather than for commercial use.




292

Summary

With Single Radio Voice Call Continuity (SRVCC), speech services in the LTE network can

be maintained when it is handed over to a GERAN network or UTRAN network.

Benefits

The speech service can be maintained when it is handed over from the GERAN to the

UTRAN.

Description

At the initial stage of the LTE project, the 3GPP defines that only the packet service is

supported. In the evolution from GERAN to LTE, the 3GPP R8 defines two solutions:

SRVCC and CSFB, to realize the interoperability of speech services between GERAN and

LTE.

To implement the SRVCC solution, the IP Multimedia Subsystem (IMS) must be deployed at

the CN and the speech service must be provided. With the assistance of the VoIP speech

service routing, control, and triggering by the IMS and the handover control by the Mobile

Management Entity (MME), the speech service in the LTE network can be handed over to the

GERAN/UTRAN smoothly.

In SRVCC, speech services are implemented in the LTE packet network, so technically the

SRVCC solution can be regarded as a real LTE VoIP technique. Through circuit switch in

GERAN network or packet switch in LTE network, the UE can access IMS based on which

the speech service is maintained. SRVCC supports handover of speech services from LTE to

GSM only.

SRVCC is available only when GERAN network and LTE network cover the same area.

GBSS12.0 does not support SRVCC in DTM mode.

Enhancement

None

Dependency


None




None


The CN is deployed with IMS and the speech service is available.


The MSC and MGW must support this feature.




293

7.6.10 GBFD-511310 Multi Technology Neighbour Cell Based Handover

Availability


Summary

This feature supports the handover between GSM frequency bands and LTE frequency bands.

Benefits

Through this feature, an MS is handed over to a specific GSM or LTE frequency band, and

the resources of the LTE or GSM frequency band occupied by the MS before the handover are

released. This feature improves the Quality of Service (QoS) of end users, thereby increasing

the revenue of operators.

Description

This feature is an enhancement of the inter-RAT handover. It supports handovers between

frequency bands of different RATs based on the priorities of neighboring cells. Through this

feature, an MS is handed over to a frequency band of another RAT to meet the requirements

of users for mobility or to ensure that the capacity restrictions on frequency bands are not

exceeded.

This feature can be applied to the following combinations of RATs and frequency bands:

GSM 900M

GSM 1800M

LTE 800M

LTE 900M

LTE 2.6G

Enhancement

None

Dependency


None





GBFD-511303 PS Handover Between GSM and LTE Based on Quality




294

GBFD-511304 PS Handover Between GSM and LTE Based on Cell Load




7.6.11 GBFD-511312 Fast LTE Reselection at 2G CS Call Release

Availability


Summary

After an MS terminates a call in the GSM network, the MS can camp on the LTE network

according to the cell reselection indicator after release information element in the Channel

Release message, without performing a cell reselection procedure.

Benefits

This feature speeds up cell reselection so that an MS can immediately receive services in the

LTE network after terminating its call in the GSM network.

Description

Generally, after an MS terminates a call in a GSM cell, it camps on the GSM cell. If a

neighboring LTE cell meets the requirements for cell reselection, the MS can camp on the

LTE cell through a cell reselection. The MS, however, must receive system information and

perform cell reselection calculations before initiating the cell reselection. This means that the

MS cannot process services in the LTE network immediately.

When this feature is enabled, the BSS selects the best neighboring LTE cell based on the

measurement information on neighboring LTE cells after the MS terminates its call in the

GSM network. Then, the BSS sends the frequency information about the best neighboring

LTE cell to the MS by using a Channel Release message, instructing the MS to camp on the

LTE cell. By doing so, the MS can reselect an LTE cell without performing cell reselection

calculations, thereby speeding up cell reselection.

Enhancement

None

Dependency


None







295


GBFD-511309 SRVCC

GBFD-511313 CSFB



7.6.12 GBFD-511313 CSFB

Availability


Summary

The Circuit Switch FallBack (CSFB) feature enables a UE camping on the E-UTRAN

network to access the GERAN/UTRAN network through a PS handover or PS cell reselection

and then process CS services. This feature is available only when the E-UTRAN and

GERAN/UTRAN networks cover the same areas.

Benefits

This feature enables a UE to be handed over from the LTE network to the GERAN network to

process CS services, thereby protecting the investment in the GERAN network.

The GERAN network can be used to provide CS services, and the E-UTRAN network can be

used to provide high-speed PS services.

Compared with the Single Radio Voice Call Continuity (SRVCC) technique, CSFB provides

CS services for UEs in the LTE network with a simpler network structure, without deploying

the IP Multimedia Subsystem (IMS).

Description

In the LTE startup stage, the 3GPP stipulates that LTE supports only PS services. In the

evolution from GERAN to E-UTRAN, 3GPP Release 8 defines two solutions, SRVCC and

CSFB, to implement the interoperability between GERAN and E-UTRAN.

If a mature GERAN network is available in the initial stage of E-UTRAN deployment, the

operator can use the existing GERAN network to provide CS services whereas use the LTE

network to provide PS services. This saves the investment in the existing GERAN network.

With CSFB, a UE in the LTE network can be handed over to the GERAN network to process

CS services.

To implement CSFB, the SGs interface must be configured between the MSC server and the

Mobile Management Entity (MME) so that dual-mode UEs attached to the LTE network can

process services such as calling, calling response, SMS, and combined location update

between E-UTRAN and GERAN. Technically, CSFB is not a real LTE VoIP technique

because a dual-mode UE has been handed over from E-UTRAN to GERAN before it initiates

CS services.

The CSFB feature is available only when GERAN and E-UTRAN cover the same areas.

CSFB does not need the IMS, thereby simplifying the network architecture. However, every time the UE makes or receives a call, the UE is handed over from E-UTRAN to GERAN.




296

This increases the access delay. In addition, the ongoing LTE PS services are affected by the

incoming call.

Enhancement

None

Dependency


None






GBFD-511312 Fast LTE Reselection at 2G CS Call Release


The SGs interface must be configured between the MSC server and the MME.

The MS must be a GSM/LTE dual-mode MS and support CSFB.

7.7 GSM & TD-SCDMA Interoperability

7.7.1 GBFD-114302 GSM/TD-SCDMA Interoperability

Availability


Introduction

This feature enables dual-mode MSs to be handed over and reselect cells between a GSM

network and a TD-SCDMA network when the MS processes CS or PS services.

Benefits Dual-mode MSs can roam and be handed over from a TD-SCDMA network to a GSM

network. This lets dual-mode MSs enjoy continuous network coverage in scenarios with

limited TD-SCDMA coverage, for example, in the early stages of network deployment.

A GSM network can smoothly evolve into a TD-SCDMA network. This helps telecom

operators increase return on investment (ROI).




297

Description

When GSM/TD-SCDMA interoperability is enabled, dual-mode MSs can roam and be

handed over between a GSM network and a TD-SCDMA network. Huawei GSM BSS

supports MS handovers and roaming in the following scenarios:

In idle mode, an MS roams from a GSM network to a TD-SCDMA network.

In idle mode, an MS roams from a TD-SCDMA network to a GSM network.

In dedicated mode, an MS is handed over from a GSM network to a TD-SCDMA

network.

In dedicated mode, an MS is handed over from a TD-SCDMA network to a GSM

network.

Currently, Huawei GSM BSS does not support PS domain handovers. Interoperability

between TD-SCDMA networks and GPRS/EDGE networks is implemented by using the

autonomous cell reselection of MSs. The inter-RAT network assisted cell change (NACC)

function can speed up the cell reselection from a TD-SCDMA network to a GPRS/EDGE

network. The network-controlled cell reselection from a GPRS/EDGE network to a

TD-SCDMA network is implemented by using the inter-RAT Network Control Cell

Reselection Mode 2 (NC2) function.

Enhancement

This feature solves the problem of some GSM terminals breaking down or restarting when a

neighboring TD-SCDMA cell is broadcast in a system information message. In addition, this

feature enables dual-mode MSs to be handed over between a GSM network and a

TD-SCDMA network.

Dependency


None




None


The MS, MSC, SGSN, HLR, and the NEs in the TD-SCDMA network must support this

feature.

7.7.2 GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA

Availability





298

Summary

The Iur-g interface is used for information exchange between the BSC and the TD-RNC.

Through the information exchange and common measurement procedures, the BSC and

TD-RNC can obtain the capacity and load information of each other.

Benefits

The GSM/TD-SCDMA inter-RAT handover mechanism is developed into a mechanism

similar to BSC internal handover in GSM900/1800. In this way, the handover procedure is

simplified. This decreases the handover delay and increases the handover success rate,

improving the customer experience.

Description

The Iur-g interface is introduced because the existing GSM/TD-SCDMA inter-RAT handover

does not meet the requirements of telecom operators in terms of the handover delay and the

handover success rate. The Iur-g interface is used for the information exchange between the

BSC and the TD-RNC, increasing the GSM/TD-SCDMA inter-RAT handover success rate

and decreasing the handover delay.

The Iur-g interface supports the information exchange and common measurement procedures.

The information exchange procedure is used for exchanging capacity information between the

BSC and the TD-RNC. The common measurement procedure is used for exchanging load

information between the BSC and the TD-RNC.

1. Information exchange procedure

Currently, the information exchange procedure can only be initiated by the TD-RNC and

terminated by the BSC. In this procedure, the TD-RNC sends the BSC an information

exchange initialization request message, specifying the measurement objects (CGI of the

GSM cell), information exchange type (Cell Capability Class/NACC Related Data), and

reporting mode (On Demand/On Modification).

The reporting mode is described as follows:

1) On demand: Upon receiving the information exchange initialization request message from

the TD-RNC, the BSC returns the cell capacity information through a response message.

2) On Modification: Upon receiving the initialization request message from the TD-RNC, the

BSC returns the cell capacity information through a response message. If the information is

changed later, the BSC notifies the TD-RNC of the change through an Information Report

message.

2. Common measurement

Currently, the common measurement procedure can only be initiated by the TD-RNC and

terminated by the BSC. In this procedure, the TD-RNC sends the BSC a common

measurement initialization request message, specifying the measurement objects (CGI of the

GSM cell), measurement type (Load/RT Load/NRT Load), and reporting mode (On

Demand/event-triggered/periodic).

The reporting mode is described as follows:

1) On demand: Upon receiving the common measurement initialization request message from

the TD-RNC, the BSC returns the cell load information through a response message.




299

2) Periodic: Upon receiving the common measurement initialization request message from the

TD-RNC, the BSC returns the common measurement initialization response message.

Subsequently, the BSC periodically reports the common measurement results according to the

specified period.

3) Event-triggered: Upon receiving the common measurement initialization request message

from the TD-RNC, the BSC returns the common measurement initialization response message.

Subsequently, the BSC reports the common measurement results when the event triggers the

conditions.

Enhancement

None

Dependency


The BSC must be configured with a pair of IP interface boards for the Iur-g interface.


None


None


None

7.7.3 GBFD-511402 Radio Resource Reserved Handover Between GSM/TD-SCDMA Based on Iur-g

Availability


Summary

Through the information exchange on the Iur-g interface between the BSC and the TD-RNC,

radio resource reservation is added to the standard GSM/TD-SCDMA handover procedure. In

this way, the resource reservation procedure is completed without the assistance of the CN.

The original redirecting procedure is maintained for compatibility with the CN.

Benefits

This feature works with GSM/TD-SCDMA inter-RAT handover to reduce the handover delay

by 80 ms and increase the handover success rate by 0.8% in a co-CN scenario, according to

the theoretical analysis results.

Description

The existing TD-SCDMA/GSM inter-RAT handover mechanism is transformed into a

mechanism similar to BSC internal handover in GSM900/1800. In this way, the handover




300

procedure is simplified. This decreases the handover delay and increases the handover success

rate, improving the customer experience.

This feature complies with the specifications of China Mobile. Through the information

exchange on the Iur-g interface between the BSC and the TD-RNC, radio resource reservation

is added to the standard GSM/TD-SCDMA handover procedure. In this way, the resource

reservation procedure is completed without the assistance of the CN.

The TD-RNC selects an optimum target cell to perform handover based on the signal level,

capacity, and load of neighboring GSM cells. In advance of the handover, the TD-RNC

reserves radio resources through the Iur-g interface to reduce the handover delay. This feature

is advantageous especially in scenarios of heavy load, fast fading, and high-speed movement

in GSM.

The radio resource handover procedure is described as follows:

After receiving measurement reports (MRs) from the UE, the TD-RNC selects an optimum

target cell to perform handover based on the capacity and load of neighboring GSM cells. The

TD-RNC requests Iur-g SCCP links for this UE and sends the BSC an Enhanced Relocation

Resource Request message, requesting radio resources for this UE.

Upon receipt of the Enhanced Relocation Resource Request message, the BSC assigns a

D-RNTI to the UE, reserves radio resources according to the requested Speech Version, and

responds to the TD-RNC with an Enhanced Relocation Resource Response message.

Optionally, this message can carry the capacity and load information of the GSM cell.

After receiving the Enhanced Relocation Resource Response message, the TD-RNC sends the

UE the associated radio resources through the Handover From Utran Command message. At

the same time, it sends the CN a Relocation Required message. Upon receipt of the message,

the CN sends the BSC a Handover Request message. After the BSC completes the setup of A

interface resources, the UE is handed over to the target cell according to the traditional

inter-RAT handover procedure.

Enhancement

None

Dependency


The BSC must be configured with a pair of IP interface boards for the Iur-g interface.


None


GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA


None




301

7.7.4 GBFD-511403 Extended BCCH

Availability


Summary

When this feature is enabled, SI2Quater and SI13 messages are broadcast on the extended

BCCH. This speeds up system information message broadcasting and shortens the delay in

inter-RAT cell reselection.

Benefits

This feature shortens the delay in inter-RAT cell reselection between a GSM network and a

TD-SCDMA network.

Description

If SIQuater and SI13 messages are broadcast on a BCCH, they are multiplexed on the same

BCCH as other system information messages. In addition, only one SIQuater or SI13 message

is broadcast in several scheduling periods. This prolongs inter-RAT cell reselection.

If SI2Quater and SI13 messages are specified to be broadcast on an extended BCCH, only

these two types of messages are broadcast on the extended BCCH. In addition, one SIQuater

or SI13 message is broadcast in each scheduling period. This speeds up the scheduling and

broadcasting of SI2Quater and SI13 messages.

As a result, MSs quickly obtain system information messages for inter-RAT cell reselection,

and the delay in cell reselection decreases.

Enhancement

None

Dependency


None




None






302

7.7.5 GBFD-511405 NC2 between GSM and TD-SCDMA

Availability

This feature is introduced in GBSS14.0 only for tests.

Summary

On a GSM and TD-SCDMA hybrid network, MSs in packet transfer mode using NC2

periodically send measurement reports (MRs) to the BSC. Upon receiving the MRs, the BSC

initiates a cell reselection from GSM to TD-SCDMA for the MSs in NC2 mode based on the

receive level, cell load, and receive quality of the serving cell, as well as the receive level, cell

load, and service duration of neighboring TD-SCDMA cells.

Benefits

By comprehensively considering the receive level, cell load, and receive quality of the serving

cell, as well as the receive level, cell load, and service duration of neighboring TD-SCDMA

cells, the BSC instructs GSM/TD-SCDMA dual-mode MSs to reselect to TD-SCDMA cells

so that PS services are preferentially allocated to the TD-SCDMA network. This prevents

such MSs from reselecting to GSM cells with a high signal strength, therefore improving user

experience and increasing network capacity.

Description

The BSC provides two sets of parameters for GSM/TD-SCDMA dual-mode MSs in idle or

packet transfer mode. The differentiated parameter setting allows dual-mode MSs in packet

transfer mode to measure the load and signal level of TD-SCDMA neighboring cells and to

report the measured values in MRs sent to the BSC.

According to the MRs sent by MSs, the BSC initiates a cell reselection from GSM to

TD-SCDMA for MSs in NC2 mode and selects neighboring TD-SCDMA cells, whose load is

lower than a specified threshold and whose receive level meets the minimum requirement, as

candidate cells. The BSC also monitors the PS service duration of MSs. If the service duration

of an MS in packet transfer mode exceeds a specified value, the BSC instructs the MS to

reselect to a TD-SCDMA cell.

The BSC obtains the loads of neighboring TD-SCDMA cells through the Iur-g interface

between the GSM BSC and the TD-SCDMA RNC during the common measurement

procedure of a cell.

Enhancement

None

Dependency


None






303



GBFD-511401 Iur-g Interface Between GSM and TD-SCDMA

This feature is mutually exclusive with the following feature:

Optimization of GSM/TD-SCDMA inter-RAT cell reselection for MSs in packet transfer

mode in GBFD-114302 GSM/TD-SCDMA Interoperability


This feature requires GSM/TD-SCDMA dual-mode MSs that support the NC2 procedure.

The TD-SCDMA RNC must support the Iur-g interface to obtain the loads of neighboring

TD-SCDMA cells.




Page 304 of 362

8 Network Security

8.1 Security

8.1.1 GBFD-113501 A5/1 and A5/2 Ciphering Algorithm

Availability


Summary

This feature is used when the voice, data, and signaling of the user are transmitted over the

Um interface.

Benefits


An evident advantage of the GSM system over the analog system is that the

unauthorized users are prohibited to access the network and the data of the authorized

users is encrypted through sophisticated ciphering algorithm, ensuring the

communication security.

The ciphering algorithm is referred to as A5 algorithm, which is a 114-bit ciphering

sequence according to the GSM specifications. The GSM specifications define eight

ciphering algorithms: A5/0–A5/7. With this feature, all the voice and signaling

information over the Um interface are transmitted in A5/1 or A5/2 ciphering mode. This

ensures the network security.

Description

The GSM specifications define eight ciphering algorithms: A5/0–A5/7. A5/0 indicates "Not

encrypted". With this feature, all the voice and signaling information over the Um interface

are transmitted in A5/1 or A5/2 ciphering mode. This ensures the network security.

Ciphering procedure

The MSC uses the Cipher Mode CMD message (including the required ciphering

algorithms and the key Kc) to initiate the ciphering procedure through the BSC. Then, according to the ciphering algorithm supported by the MS, the ciphering algorithm

required by the MSC, and the ciphering algorithm allowed by the BSC, the BSC decides




305

the algorithm to be used and notifies the BTS of the decision. The BSC then sends the

Ciphering Mode CMD message to notify the MS of the ciphering algorithm. After

receiving the Ciphering Mode CMD message, the MS initiates the transmission in

ciphering mode.

Enhancement

None

Dependency


None




None



8.1.2 GBFD-113503 A5/3 Ciphering Algorithm

Availability


Summary

This feature is used when the voice, data, and signaling of the user are transmitted over the

Um interface.

Benefits


An evident advantage of the GSM system over the analog system is that the

unauthorized users are prohibited to access the network and the data of the authorized

users is encrypted through sophisticated ciphering algorithm, ensuring the

communication security.

The ciphering algorithm is referred to as A5 algorithm, which is a 114-bit ciphering

sequence according to the GSM specifications. The GSM specifications define eight

ciphering algorithms: A5/0–A5/7. With this feature, all the voice and signaling

information over the Um interface are transmitted in A5/3 ciphering mode. This ensures

the network security.

Description

For details, see the description of the A5/1 and A5/2 ciphering algorithm.




306

Enhancement

None

Dependency


None

Impact on the BTS hardware



None



8.1.3 GBFD-113521 A5/1 Encryption Flow Optimization

Availability


Summary

With this feature, the BTS optimizes the A5/1 ciphering algorithm to improve the network

security.

Benefits

Information security becomes increasingly important as the subscribers use MSs to browse

webpages and do business on the network. This feature aims to solve the low security

problem of the A5/1 ciphering algorithm and therefore improve the data transmission security

by optimizing the service processing procedure and increasing the complexity of network

wiretapping.

Description

With the technology development, some hacker organizations state that they can attack the

calls encrypted by the A5/1 ciphering algorithm within 30 seconds in ideal conditions.

Huawei studies the manner in which hackers attack, and prepares a scheme to enhance the

A5/1 ciphering algorithm. With this scheme, only the network software needs to be upgraded.

Therefore, hackers can attack the calls with a success rate of a maximum of only 10% within

40 successive days. In this manner, the data transmission security is greatly improved.

The ciphering procedure is optimized from the following aspects:

Fast SDCCH handover is adopted in the MS access procedure. This increases the

difficulty for an intruder to trace the calls of an MS.

The TCH timing handover is introduced to increase the difficulty for an intruder to trace

an MS.




307

The Hopping Sequence Number (HSN) in the Flex Training Sequence Code (TSC) and

Flex Mobile Allocation Index Offset (MAIO) differentiates one TCH from another.

Therefore, the characteristics of TCHs are different and an intruder cannot trace other

TCHs according to the characteristics of a TCH.

After the BTS sends a ciphering command, it stops sending System Information 5, 5bis,

and 5ter over the SACCH on the SDCCH.

The dummy bits are randomized.

Enhancement

None

Dependency


None





GBFD-115830 VAMOS


None

8.1.4 GBFD-113522 Encrypted Network Management

Availability


Summary

The encrypted network management is related to the secure socket layer (SSL). This feature

allows the establishment of a TCP transmission channel between the network management

server and a network element (NE) based on the encrypted SSL.

Benefits


With the rapid development of the radio network, operators have higher requirements for

the OM transmission security. Therefore, the encryption of the OM transmission channel

becomes a basic requirement.

The encryption of the OM transmission channel involves the encryption of the data

transmitted between the LMT and the NE and of the data transmitted between the BSC

and the BTS.




308

This feature ensures the confidentiality of the data transmitted through the OM

transmission channel, therefore effectively protecting the privacy of the subscriber data

and reducing the risk that the transmitted plain text is intercepted.

Description

In many scenarios of the communication between the network management system and the

NE, a large amount of data is transmitted in the form of data files, including performance data

file, log file, configuration data file, version file, and patch file. The traditional plain text

transmission in the network is a threat to the secrecy of the transmitted data files.

With the encrypted network management feature, a transmission channel based on the

encrypted SSL is established between the network management server and the NE during the

establishment of the TCP connection. The data is then transmitted over this encrypted

channel.

The encrypted network management feature supports the transmission of plain text and cipher

text, and therefore does not affect the normal communication between the network

management server and the NE that does not support the encrypted SSL.

Network management server

(supporting encrypted SSL)

New network element

(supporting encrypted

SSL)

Old network element

(not supporting

encrypted SSL)

Cipher text

Plain text

Application layer

Transport layer (TCP)

Application layer

Secure socket layer (SSL)

Transport layer (TCP)

Transmission before

encryption

Transmission

after encryption




309

This feature complies with RFC4217, and supports two SSL protocol versions, namely,

SSL3.0 and TSL1.0.

Enhancement

None

Dependency


None




None



WOFD-210100 Encrypted Transmission

8.1.5 GBFD-113524 BTS Integrated IPsec

Availability


Summary

The BTS Integrated IPsec feature encrypts data transmitted between a BTS and a BSC that

are connected over an external gateway. This ensures data confidentiality, integrity, and

non-repeated sending and provides operators a secure end-to-end network.

Benefits

This feature protects IP packets transmitted through an IP network from being intercepted or

modified, providing an end-to-end protection for user data.

Description

Internet Protocol Security (IPsec) is a protocol suite for securing IP communications. IPsec

uses the Authentication Header (AH) and Encapsulating Security Payload (ESP) protocols to

provide the following functions:

Data confidentiality: Data is transmitted in ciphertext.

Data integrity: Received data is checked to ensure that it is not modified.

Data source verification: The credibility of the data source is checked.




310

Repeated data rejection: Old or repeated packets are rejected to avoid attacks from

malicious users who repeatedly send intercepted data.

To simplify the use and management of IPsec, Internet Key Exchange (IKE) is defined and

provides the following functions to enhance bearer network security:

Performs automatic key negotiation.

Sets up and maintains security associations.

IKE supports peer-end identification by using pre-shared keys and digital certificates.

This feature is configured and maintained on the BSC. To enable this feature, the BSC must

be connected to a BTS over an external gateway.

Enhancement

None

Dependency


None




This feature should be used together with the following feature:

GBFD-113526 BTS Supporting PKI




None

8.1.6 GBFD-113526 BTS Supporting PKI

Availability


Summary

This feature enables an NE to automatically obtain a digital certificate authorized by the

Certificate Authority (CA) of an operator. The NE with a digital certificate can be authenticated

by the Internet Protocol Security (IPsec), IEEE 802.1X-2004 standard, or Secure Socket Layer

(SSL) protocol.




311

Benefits

By authenticating NE identification, the Public Key Infrastructure (PKI) feature prevents

malicious users from accessing the network and therefore improves the network security. This

feature is used in conjunction with encryption technologies provided in IPsec or Secure Socket

Layer (SSL) to protect user data from being intercepted or modified.

Description

Based on Certificate Management Protocol version 2 (CMPv2), this feature provides a suite

of functions that apply to certificate management between NEs. The suite includes functions

such as certificate register request, key update, key restore, certificate revocation,

cross-certification, CA key update notification, certificate authorization notification, and

certificate revocation notification.

This feature manages the local digital certificate for a BTS based on CMPv2. Figure 8-1

shows how CMPv2 is applied in PKI.

Figure 8-1 Application of CMPv2 in PKI

During the digital certificate management process, this feature provides the following

functions:

1. BTS entity initialization: BTS entity initialization involves importing the public key of

the root certificate and obtaining options supported by the PKI management entity.

2. Certificate request: A certificate is authorized in the following scenarios:

Initial registration and certification




312

The CA or registration authority (RA) identifies a BTS before authorizing a certificate to

the BTS. If the initial registration and certification is successful, the CA uses the public

key of the BTS to authorize a certificate for it. Then, the CA sends the certificate to the

BTS or releases the certificate to the public database.

Key pair update

Each key pair is updated periodically. Each update requires a new certificate.

Certificate update

A certificated must be updated before it expires.

CA key pair update

Each CA key pair is updated periodically.

3. Certificate revocation: The BTS revokes a certificate by sending a certificate revocation

request to the CA.

Enhancement

None

Dependency


None




None


None

8.2 Reliability

8.2.1 GBFD-117801 Ring Topology

Availability


Summary

The ring topology is a special chain topology. Several BTSs form a chain, and the

lowest-level BTS is connected to the BSC through the transmission link, forming a ring. If

there is a breakpoint on the ring, the BTSs that precede the breakpoint remain unchanged in

networking mode whereas the BTSs that follow the breakpoint form a new chain connection

in the reverse direction.




313

Benefits

Compared with the ordinary chain topology, the advantage of the ring topology is that when a

connection is broken, the ring automatically breaks into two chains. In this way, the BTSs that

precede and follow the breakpoint can work normally, improving the robustness of the

system.

Description

The ring topology supports the following operations:

Automatic switchover

Manual switchover

Querying and dynamically configuring of the switchover parameters

Dynamic data configuration such as adding or deleting a BTS, cell, or TRX.

Figure 8-2 and Figure 8-3 show the ring topologies of the BTS:

Figure 8-2 Ring topology (1)

Figure 8-3 Ring topology (2)




314

Numbers 0 and 1 shown in Figure 8-2 refer to port 0 and port 1 of the BTS. In the BTS ring

topology, the link established at port 0 is a forward link and the link established at port 1 is a

reverse link.

The BTS ring topology can be implemented between interface boards but not between

subracks. In other words, the BTS ring topology must be implemented between the GEIUBs

located in the same subrack, as shown in Figure 8-3.

Generally, the BTS ring topology is a chain of BTS0, BTS1, and BTS2 in sequence, known as

a forward direction. In the forward direction as shown in Figure 8-2, BTS0 is the highest-level

BTS, BTS1 is the second-level BTS, and other BTSs are connected analogically. When the

link A, B, C, or D is broken, the BTSs that precede the breakpoint remains in the same

topology, and the BTSs that follow the breakpoint form a chain in a reverse direction.

The BTS ring topology is categorized into two types: Huawei BTS ring topology I and

Huawei BTS ring topology II. In BTS ring topology I, the BTS with a reverse link is

initialized again after transmission disruption, and therefore the services of the BTS are

interrupted. In BTS ring topology II, the services of the BTS with a reverse link are not

interrupted after transmission disruption.

Enhancement

Fast Ring Network Switch function is introduced in GBSS8.0.

With this feature, when a transmission link in the ring network is faulty, all the BTSs behind

the breaking point in the ring network perform the switchover in the reverse direction.

The Fast Ring Network Switch feature accelerates the ring network switchover and the BTS

does not need to be initialized in the reverse ring direction. Therefore, the call drops due to

the ring network switchover and the impact of the switchover on the new calls are reduced.

This improves the network reliability and user experience.

Dependency


None







GBFD-113728 OML Backup


"Huawei BTS ring topology II" is mutually exclusive with GBFD-117301 Flex Abis






315

8.2.2 GBFD-113801 TRX Cooperation

Availability


Summary

With this feature, when the BCCH TRX or the TRX involved in baseband FH is faulty, the

cell automatically rectifies the faults. Therefore, the services in the cell are not affected before

the faulty TRX is replaced.

Benefits

The TRX Cooperation feature ensures that the cell provides services continuously. This

feature reduces the probability that the cell is out of service because of the faulty BCCH TRX.

It also reduces the probability that the call quality in the cell is degraded because of the faulty

TRX involved in the baseband FH. Therefore, the reliability of the network is greatly

improved.

Description

With this feature, when the BCCH TRX or the TRX involved in baseband FH is faulty, the

cell automatically rectifies the faults. Therefore, the services in the cell are not affected before

the faulty TRX is replaced.

Based on the type of faulty TRXs and the handling method, the TRX cooperation is classified

into BCCH TRX cooperation and baseband FH TRX cooperation. For the non-baseband FH

cell, only the BCCH TRX cooperation occurs. For the baseband FH cell, both BCCH TRX

cooperation and baseband FH TRX cooperation are likely to occur.

BCCH TRX cooperation

In the idle state, the MS needs to obtain information through the broadcast messages sent

on the BCCH. The messages carry information about cell selection, adjacent cell, access

control, dedicated channel control, cell identification code, location, and system

parameters related to the PS services. When a BCCH TRX of a cell is faulty, all the

services in this cell are interrupted. Therefore, when the BCCH TRX is faulty, another

available TRX of the cell is used to substitute the faulty BCCH TRX to ensure that the

cell can continue to provide services. After the fault in the original BCCH TRX is

rectified, the BSC can switch the BCCH back to the original TRX. This process is called

BCCH TRX cooperation.

Baseband FH TRX cooperation

In the baseband FH cell, if the TRX involved in baseband FH is faulty, some speech

frames in the call using the FH channel are lost. Therefore, the speech quality is

degraded. To ensure the speech quality in the cell, the BSC enables the baseband FH

TRX cooperation and remove the faulty TRX from the FH and continue the FH mode

with the fine running TRX. In this way, the speech quality of the cell is not affected by

the faulty TRX. This process is called baseband FH TRX cooperation.

When the BCCH TRX in a baseband FH cell is faulty, baseband FH TRX cooperation

can also be performed. That is, the cell is changed to the non-FH mode. After all the

faults in the original BCCH TRX and in the TRX involved in FH are rectified, the

baseband FH TRX cooperation can be performed. That is, the BSC changes the non-FH

mode to the FH mode.




316

Enhancement

None

Dependency


None




None


None

8.2.3 GBFD-117401 MSC Pool

Availability


Summary

With this feature, multiple MSCs form a resource pool to provide services for the subscribers

belonging to one group of BSCs.

Benefits

The MSCs in an MSC pool share the traffic load and resources. Therefore, this feature

provides the following benefits:

This feature increases the network capacity and saves the equipment investment.

This feature realizes the redundancy backup and therefore improves the network

reliability because the addition or deletion of an MSC does not affect the services.

This feature automatically adjusts the traffic load on an MSC and reduces the operation

and maintenance cost of operators.

The MSC pool is logically an MSC. Therefore, the number of handovers between MSCs

is reduced and the network performance is improved.

Description

With this feature, a maximum of 32 MSCs form a resource pool to provide services for the

subscribers under one group of BSCs. Through the MSC pool, one BSC can be connected to

multiple MSCs simultaneously. In addition, the traffic on the BSC is evenly distributed to the

MSCs in the pool according to the NRI or load balancing principle. The following figure

shows the typical networking of the MSC Pool feature:




317

Area 1

RAN node

Area 5

RAN node

Area 6

RAN node

Area 7

RAN node

Area 8

RAN node

Area 2

RAN node

Area 3

RAN node

Area 4

RAN node

PS pool- area 2 PS pool- area 1

CS pool- area 2

CS pool- area 1

MSC 3

MSC 2

MSC 1

MSC 6

MSC 5

MSC 4 MSC 7

In the preceding figure, MSC 1, MSC 2, and MSC 3 form an MSC pool. All the CS services

or PS services in the BSC service areas (Area 1, Area 2, Area 5, and Area 6) are routed to the

MSC pool for further processing. The routing policies are described as follows:

Routing by network load

For the newly-registered MS, the BSC selects an MSC by using the load balancing

algorithm based on the IMSI carried in the CMP L3 message, the status of MSCs in the

MSC pool, and the available capacity. Then, the BSC directs the traffic of the MS to the

selected MSC for processing.

If the MS without the SIM card initiates an emergency call, the BSC selects the MSC

based on the IMEI, the status of MSCs in the MSC pool, and the available capacity and

then directs the traffic of the MS to the selected MSC for processing.

Routing by the NRI

After the MS is registered, the MSC allocates the TMSI containing the NRI to the MS.

The NRI is used for identifying an MSC in the MSC pool. During the call processing,

the MS sends the TMSI to the network side. On receiving the TMSI, the BSC resolves

the NRI from the TMSI and then directs the traffic to the MSC based on the MSC

signaling point corresponding to the NRI in the configuration data.

With this feature, the BSCs in the pool area share a group of MSCs. If heavy traffic

hours of each BSC are different, less CN resources are required compared with the

network where the MSC Pool feature is disabled. This saves the investment in the CN

equipment.

When an MSC in the MSC pool is faulty, the traffic of the newly accessed MS is

automatically directed to another normal MSC, enhancing the network reliability. When

some maintenance operations such as software upgrade are performed on an MSC in the

MSC pool, the traffic on this MSC can be easily directed to other MSCs. After the

operation is complete, the traffic is reallocated to the original MSC. This reduces the

service interruption duration and therefore improves the user satisfaction.




318

Enhancement

GBSS8.0

The MSC Pool feature in case of A over IP is supported.

GBSS9.0

MSC pool measurements supported: The service requests sent to each MSC in the MSC pool

are counted on the basis of the access method (IMSI, IMEI, or TMSI) used by the MSs. This

helps the operators learn the distribution of MSs using various access methods.

Dependency


None




None


The NSS must support this feature.


WOFD-230100 MSC Pool Management

8.2.4 GBFD-119701 SGSN Pool

Availability


Summary

With this feature, multiple SGSNs form a resource pool to provide services for the subscribers

belonging to one group of BSCs.

Benefits

The SGSNs in an SGSN pool share the traffic load and resources. This feature provides the

following benefits:

Increases the network capacity and saves the investment on equipment.

Implements redundancy backup and therefore improves the network reliability because

the addition or deletion of an SGSN does not affect the services.

Reduces handovers between the SGSNs because the SGSNs in an SGSN pool are

logically one SGSN and therefore improves the network performance.




319

Description

This feature, which is similar to the MSC Pool feature, enables a maximum of 32 SGSNs to

form a resource pool to provide services for the subscribers belonging to one group of BSCs.

With this feature, one BSC can be connected to multiple SGSNs at the same time. In addition,

the traffic on the BSC is evenly distributed to the SGSNs in the pool according to the network

resource identifier (NRI) or load balancing principle.

Area 1

RAN node

Area 5

RAN node

Area 6

RAN node

Area 7

RAN node

Area 8

RAN node

Area 2

RAN node

Area 3

RAN node

Area 4

RAN node

PS pool- area 2 PS pool- area 1

CS pool- area 2

CS pool- area 1

SGSN 6

SGSN 2

SGSN 1

SGSN 5

SGSN 4

SGSN 3

The routing policies are described as follows:

Routing by network load

When an MS accesses the network for the first time, it generates a random TLLI and

sends it to the BSC because it does not have a local/foreign TLLI. Then, the BSC uses

the load balancing algorithm to select an SGSN for the MS according to the status and

available capacity of the SGSNs in the pool and routes the MS to the selected SGSN.

Routing by the NRI

After an MS accesses the network for the first time, the SGSN allocates a new local

TLLI that includes the NRI information associated with this SGSN to the MS. When the

MS processes services, it sends the NRI information to the network through the

local/foreign TLLI. Then, the BSC obtains the NRI from the local/foreign TLLI and

routes the services to the SGSN corresponding to the NRI in the configuration data.

Using the SGSN pool, the BSCs in the pool share a group of SGSNs. If peak hours of

traffic on each BSC are different, less CN resources are required in comparison with the

non-SGSN pool networking. This saves the investment in the CN equipment.

When an SGSN in the SGSN pool is faulty, the new services are automatically

transferred to another normal SGSN and therefore the network reliability is enhanced.

When some maintenance operations such as software upgrade are performed on an

SGSN in the SGSN pool, the traffic on this SGSN can be easily transferred to other

SGSNs. After the operation is complete, the traffic is reallocated to the original SGSN.




320

This reduces the service interruption duration and therefore improves the user

satisfaction.

Enhancement

None

Dependency


None




None


The SGSN must support this feature.


WOFD-230700 SGSN Pool Management

8.2.5 GBFD-116601 Abis Bypass

Availability


Summary

In the case of chain topology, when the power supply to a BTS fails, this feature can bypass

this BTS (that is, this BTS is used only as the path) so that the signals of the lower-level BTSs

can be sent to the BSC.

Benefits

Chain topology is the main topology among the current networking modes. In the chain

topology, if the power supply to the upper-level BTS fails, the transmission of the lower-level

BTSs cannot proceed normally. With this feature, the lower-level BTSs can work normally

even if the power supply to the upper-level BTS fails. Therefore, this feature provides higher

reliability for the network in the chain topology, especially in the areas where the power

supply fails frequently.

Description

To improve the working capability of the BSS system in the areas where the power supply

fails frequently, Huawei BTS provides the Abis Bypass feature. This feature is applicable in

the case of chain topology. When the power supply to a BTS fails, the BTS automatically bypasses the Abis interface so that the lower-level BTSs in the chain network can work




321

normally. When the power supply is recovered, the BTS and the lower-level BTSs are reset

automatically.

Enhancement

In GBSS8.1, this feature is supported from the 3900 series base stations.

Dependency


None











GBFD-117301 Flex Abis(in TDM network, this feature is exclusive only with Ring Topology

is using)



8.2.6 GBFD-113721 Robust Air Interface Signalling

Availability


Summary

With this feature, the FACCH frames and SACCH frames are sent repeatedly when the radio

quality is poor. Therefore, this feature enhances the anti-interference capability of the

signaling links on the FACCH and SACCH and increases the possibility that the MS and the

BSC successfully receive the signaling messages. This feature involves repeated sending of

downlink FACCH frames and repeated sending of uplink/downlink SACCH frames.

Benefits





322

Repeated sending of FACCH frames improves the FACCH link performance of the

ordinary MS by 2 dB and the FACCH link performance of the MS in R6 version by 4 dB

to 5 dB.

Repeated sending of SACCH frames improves the SACCH link performance of the

ordinary MS by 4 dB to 5 dB.

The improvement in the FACCH and SACCH performance reduces call drops and

increases the accuracy of the handover decision and power control decision of the BSC.

Description

In the network with tight frequency reuse and poor radio transmission performance, the

messages sent through the FACCH frames or the SACCH frames may be lost because of the

high bit error rate on the Um interface. This feature involves repeated sending of downlink

FACCH frames and repeated sending of uplink/downlink SACCH frames.

Repeated sending of downlink FACCH frames

When the receive quality in the downlink measurement report is lower than the specified

threshold, the BTS determines whether to resend the FACCH frames. The repeated

sending of downlink FACCH frames can increase the possibility that the MS

successfully receives the signaling messages.

Repeated sending of uplink/downlink SACCH frames

If the BTS detects that the SACCH frames are incorrectly decoded, it instructs the MS to

resend the recent SACCH frame. If the MS detects that the SACCH frames are not

correctly decoded, it instructs the BTS to resend the recent SACCH frame.

With this feature, the voice quality is slightly affected because the signaling messages are sent

through frame stealing.

When the radio quality is poor, repeated sending of signaling messages in the downlink can

reduce call drops caused by decoding failure. Repeated sending of signaling messages in the

uplink can increase the accuracy of the handover decision and power control decision of the

BSC by increasing the possibility of correctly decoding the uplink measurement reports.

Enhancement

None

Dependency


None




None


The MS and the BTS must support this feature.




323

8.2.7 GBFD-117803 Abis Transmission Backup

Availability


Summary

This feature applies to Abis over TDM or Abis over IP mode to improve network reliability.

In Abis over TDM mode, this feature switches services to standby satellite transmission links

if terrestrial TDM transmission links over the Abis interface become faulty due to an

exception caused by a natural disaster. In Abis over IP mode, this feature allows users to

configure two transmission links over the Abis interface: an IP over E1 transmission link

based on the existing TDM or SDH network and an IP over FE transmission link based on the

IP network.

Benefits

This feature improves the reliability of the Abis interface when TDM transmission or IP over

FE transmission is applied over the Abis interface.

Description

During a natural disaster, GBSS devices sometimes work normally; however, the GSM

network cannot provide services because of terrestrial transmission interruption. With this

feature, the standby satellite transmission links can be used for communication between the

BSC and the BTS so that GSM devices can provide services in emergency conditions.

When this feature is enabled, satellite transmission links are used as backup for terrestrial

transmission links. When the terrestrial transmission link is faulty, the GBSS automatically

uses the satellite transmission link. When the active terrestrial transmission links recover, the

GBSS devices can be triggered by hand to make the transmission link rollback to use the

terrestrial transmission links again.

With this feature, no information is transmitted over the standby satellite transmission links.

This saves satellite link bandwidth.

The satellite transmission link switchover applies only to the Abis over TDM mode.

Enhancement

GBSS14.0

Standby Abis transmission links

In Abis over IP mode, this feature allows users to configure two transmission links over the

Abis interface: an IP over E1 transmission link based on the existing TDM or SDH network

and an IP over FE transmission link based on the IP network.

The two transmission links over the Abis interface work in active/standby mode, and services

are carried only on the active transmission link in normal conditions. The active transmission

link uses Link Access Procedure on the D channel (LAPD) detection and the standby

transmission link uses User Datagram Protocol (UDP) Ping detection. If the active

transmission link becomes faulty, the GBSS automatically switches all services over the Abis interface to the standby transmission link. Services are interrupted for less than 1 minute




324

during the switchover. When the original active transmission link recovers, the GBSS

automatically switches all services back to it. If the standby transmission link becomes faulty,

services are not switched over but an alarm is reported, notifying that the standby

transmission link is faulty.

Standby Abis transmission links apply only when one transmission mode (IP over FE or IP

over E1) is used between the BTS and the BSC. Standby Abis transmission links do not apply

when the transmission mode is changed by a router over the bearer network. For example, the

transmission mode is changed from IP over E1 to IP over FE.

Dependency


None




Satellite transmission link switchover depends on the following features:

GBFD-113901 Satellite Transmission over Abis Interface


Abis transmission link backup depends on the following features:




None

8.2.8 GBFD-113725 BSC Node Redundancy

Availability


Summary

The BSC Node Redundancy feature improves the reliability and robustness of the network by

providing the 1+1 backup on the BSC level.

Benefits

The BSC Node Redundancy feature improves the reliability and robustness of the GSM

network, reduces the duration of service interruption caused by a single-point fault, and

therefore improves the service quality.




325

Description

The BSC controls the radio resources of every BTS. Once the BSC is faulty, all the BTSs

controlled by this BSC cannot access the network and the connection cannot be set up in the

coverage area of this BSC. In addition, the fault on the communication link between the BSC

and the BTS will hamper the functioning of the BSC. As a result, the network in this coverage

area of the BTS may break down.

The BSC Node Redundancy feature provides the backup scheme on the BSC level to avoid

the previous problems. The BSC supports the 1+1 backup mode. The principles of 1+1

backup are as follows:

A BTS is configured with two sets of transmission links, which are connected to the main

BSC and sub-BSCs respectively. All the data concerning the BTS, cell, neighboring cell is

backed up on the main BSC and sub-BSCs. The BTSs are generally controlled by the main

BSC. Once the main BSC is faulty, the BTS attempts to connect to the sub-BSC and continues

to provide services.

In this manner, a BTS has two sets of Abis interfaces (including two sets of control plane

links, user plane links, and OM links). In addition, two control BSCs are available to

implement cold backup (calls are not protected). Therefore, the system reliability is improved.

The main and sub-BSCs do not work in active/standby mode. Normally, they are both in

operation state, therefore the equipment can obtain maximal efficiency. If one BSC is faulty,

the other one can take over all the BTSs under the faulty BSC to prevent the BTSs from being

out of service and therefore avoid single-point faults on the BSC level. When one BSC

becomes faulty, the overall service processing capability (including CS Erlang and PS

throughput) of the pair of BSCs in 1+1 backup mode is decreased.

Enhancement

None

Dependency


A/GB/Abis/Inter-BSC interface must be IP mode, using IP interface Board.





GBFD-118601 Abis over IP or GBFD-118611 Abis IP over E1/T1

GBFD-118602 A over IP or GBFD-118622 A IP over E1/T1


GBFD-115301 Local Multiple Signaling Points



WOFD-231100 BSC Redundancy Management–GBSS




326

8.2.9 GBFD-113726 TC POOL

Availability


Summary

With this feature, multiple BSCs share the same TC resources in the TC pool. This increases

the efficiency of the codec hardware.

Benefits The efficiency of the codec hardware is increased because multiple BSCs share the same

resources in one TC pool. For the small-capacity BSC, 20% to 30% TC codec resources

can be saved.

Saving room is possible. For example, three small-capacity GTCSs require three cabinets.

In TC pool mode, three GTCSs require only one cabinet. In this manner, 40% to 60%

area in the equipment room can be saved.

Description

In general, one GTCS belongs to only one BSC and is used to process the CS services of this

BSC. The GTCSs in different BSCs are not associated with each other. In this kind of network

topology, the TC resources cannot be multiplexed among multiple BSCs. In the scenario

where multiple BSCs with small capacity are grouped into a network, the TC resources are

greatly wasted.

In TC pool mode, multiple BSCs share a TC pool of large capacity. The typical network

topology is shown in the following figure.

E1/STM-1

TC(Pool)MSC2

BSC1 (main BSC)

BSC2(sub BSC)

BSC3(sub BSC)

MSC1

MSC3

BSC4(sub BSC)

E1/STM-1

E1/STM-1

E1/STM-1

E1/STM

-1

E1/STM-1

E1/STM-1

Ater A

Abis




327

The TC pool adapts to the mode that the GTCS is separated from the BSC cabinet and is

connected to the BSC through the Ater interface. The codec resources in the TC pool are

shared by the main BSC and sub-BSCs, which work in load sharing mode. When a voice

processing board is faulty, it will out of service automatically. In this manner, the subsequent

CS services are not affected, which improves the system reliability. The speech versions

supported by the TC pool are FR, EFR, HR, AMR-FR, and AMR-HR.

To synchronize the clock of the GSM network, the main BSC and sub-BSCs in a TC pool

should use the same clock source. In addition, a BSC can be connected to only one TC pool.

One TC pool supports a maximum of 16 BSCs.

Enhancement

None

Dependency


None







GBFD-116902 Ater Compression Transmission


None

8.2.10 GBFD-113728 OML Backup

Availability


Summary

This feature supports configuration of the OMLs on two independent E1s. In this case, only

one OML works at one time. When the OML in working mode is faulty, the BTS uses another

OML. In this way, the BTS can work without being out of service.

Benefits

This feature provides better robustness for the BTS. When the OML is broken because the

transmission links are faulty, this feature ensures that the BTS is not reset and the cell is not

out of service.




328

Compared with the ring topology that requires twice the amount of resources, this feature

requires only a few timeslots. In addition, configuration of the OML on two E1s can ensure

the stable operation of the BTS system with a little consumption of the transmission

resources.

Description

The OML is the operation and maintenance link between the BSC and the BTS. When the

OML is faulty, the entire BTS cannot work. With this feature, two OMLs can be configured

on two independent E1s. When the OML in working mode is faulty, the BTS uses another

OML. Therefore, the BTS and cell can continue to work without being out of service due to

transmission fault or port fault.

When this feature is used, the BSC configures one OML on port 0 and another OML on port 1.

After the BTS is reset, it attempts to establish links on the two ports in turn. If the BTS

establishes the OML on one port, it always uses the OML on this port unless the BTS is reset

or the OML is broken. When the established OML is broken, the BTS attempts to establish an

OML on another port. If the establishment is successful, the BSC triggers the OML

switchover.

After the OML switchover, the RSL, TCH, idle timeslot, and monitoring timeslot are not

switched over. That is, for port 0 and port 1, if the transmission link or port where the working

OML is located is faulty, all the TRX channels, idle timeslots, and monitoring timeslots

become unavailable. The normal port, however, can continue to provide services. Therefore,

the BTS and cell can continue to work without being out of service.

The OM personnel can use the MML command to enable this feature.

This feature is supported by the BTS in TDM and HDLC modes. This feature is not supported

by the BTS in IP mode.

Enhancement

None

Dependency


None














329



8.2.11 GBFD-511002 Access Control Class (ACC)

Availability


Summary

With this feature, the BSC can control the number of MSs accessing the network at a certain

time by allowing only the MSs of a certain ACC class to access the network. In this manner,

the BSS overload or MSC overload caused by numerous MSs' simultaneous access to the

network can be prevented. This feature uses a sliding window mechanism to enable the MSs

of all ACC classes to access the network. Therefore, radio services are available for all MSs,

especially in emergency cases.

Benefits

In emergency cases such as natural disasters, the traffic volume in the network sharply

increases. It may increase to an extent that far exceeds the network capacity. In such a case,

users have difficulties in making calls, and the radio network may even be down. The Access

Control Class (ACC) feature controls the number of MSs accessing the network in emergency

cases by allowing only the MSs of a certain ACC class to access the network. It ensures the

normal operation of the radio network.

Description

When a subscriber is registered with the GSM network, it is assigned a common ACC class

and a special ACC class. The MSs of a certain ACC class are informed of being allowed or of

not being allowed to access the network by the GSM system through system information. The

ACC feature uses a window sliding mechanism to allow only the MSs of a certain ACC class

to access the network at a certain time. The size of the sliding window and the speed of

window motion depend on the operator's configuration policy.

Enhancement

None

Dependency


None


None


None





330

None




Page 331 of 362

9 O&M Experience

9.1 O&M

9.1.1 GBFD-113729 Adaptive Transmission Link Blocking

Availability


Summary

If the transmission quality of an E1 link over the Abis interface deteriorates, the BSC actively

blocks this E1 link, so that the link no longer carries new services. After the transmission

quality of the E1 link becomes desirable, the BSC unblocks the link.

Benefits This feature ensures the service quality by not allocating calls to E1 links with

undesirable transmission quality.

This feature reduces the costs in network monitoring and maintenance.

Description

The transmission quality, especially the quality of microwave transmission, is vulnerable to

bad weather such as raining. Once an E1 link is faulty, all services carried on the link will be

affected, which leads to degraded service quality and increased call drop rate.

To prevent the preceding problem, the BSC monitors transmission quality in real time. The

BSC automatically blocks an E1 link if the transmission quality is lower than the specified

threshold. After being blocked, the E1 link carries only the ongoing services and no longer

carries new services.

After the transmission quality of the E1 link becomes desirable, the BSC unblocks the link.

Enhancement

None




332

Dependency


None







None

9.1.2 GBFD-114701 Semi-Permanent Connection

Availability


Summary

When the semi-permanent connection feature is enabled, some of the idle E1 timeslots in the

existing network can be used to transmit information such as service hall information, alarm

information on the BTS AC power supply, and other maintenance information.

Benefits


Using semi-permanent connection prevents the arrangement of new paths to transmit the

external maintenance information. As a result, the transmission networking is simplified,

the maintenance cost is reduced, and thereby the transmission cost is greatly reduced.

With this feature, the semi-permanent connections on multiple GMPS/GEPS converge

on one E1 through the timeslot switching on the interface boards. Therefore, the

investment in the transmission and timeslot switching devices (DXX devices) are saved.

Description

When some data that does not have a high requirement for the transmission bandwidth needs

to be transmitted from one terminal to another terminal, the idle transmission resources in the

GSM network can be used.

Semi-permanent connection refers to the situation that the information collected on the E1

timeslots of the receiver is exchanged to the E1 timeslots of the transmitter through the

intra-BSS timeslot switching function. The collected information is transparently transmitted

within the BSS. The transparent transmission path is retained permanently without change in

the link configuration. The timeslot switching process is shown in the following figure.




333

Huawei BSS supports the semi-permanent connection at four rates: 8 kbit/s, 16 kbit/s, 32

kbit/s, and 64 kbit/s. The access points of all paths carrying the semi-permanent connections

into the BSS are E1 interface timeslots. The BSS switches over multiple semi-permanent

connections to one E1 and then exports the collected maintenance information to the devices

in the external network.

Huawei BSS supports two types of semi-permanent connections: common semi-permanent

connection and monitoring timeslot.

Common semi-permanent connection

In the case of common semi-permanent connection, the interface boards in the BSC are

used for input and output, and only the BSC is involved in the timeslot switching

function from the input timeslot to the output timeslot. With common semi-permanent

connection, the external information of the BSC equipment room can be sent to the CN

equipment room using the transmission resources over the A interface. In addition,

simple DXX devices can be used to combine multiple timeslots into one E1 for

transmission. As a result, the transmission cost is reduced and the DXX device

investment is saved.

Monitoring timeslot




334

With monitoring timeslot, the timeslot switching function is performed by the BTS and

the BSC. One end of the monitoring timeslot path is connected to the BTS port, and the

other end is connected to the interface board in the BSC. The monitoring timeslot is used

for transmitting external data (such as the information about the alarm of the power

supply) on the BTS side. In BTS cascading, the upper-level BTS is also involved in the

timeslot switching function to transparently transmit the monitoring timeslot data for the

lower-level BTS.

Enhancement

GBSS8.0

This application enhancement supports configuration of monitoring timeslots at the

transmission optimization site.

Dependency


None




When monitoring timeslots are used at the transmission optimization site, E1 connection

paths should be configured between the GEHUB and the GEIUB/GOIUB.


None




335

9.1.3 GBFD-116401 End-to-End MS Signaling Tracing

Availability


Summary

This feature enables you to collect the information about the specified MS if required and

then collect the traced faults in a specific network element using only a few system resources.

In this manner, you can rectify the faults effectively.

Benefits

It is difficult to locate the service faults in MSs because the communications network

becomes increasingly complicated. You can detect the section where the fault occurs only

when the information about the whole process of one MS is collected. By using the

end-to-end MS signaling tracing feature, you can completely record the service activities of

an MS and then locate the section where the fault occurs. The recorded information covers all

the network elements involved in the service of the MS. If the traced MS is properly defined,

the valid location information can be obtained without using a large amount of processing and

transmission resources of the system in the whole tracing process.

Description

With this feature, you can create or delete a tracing task in the HLR. The HLR sends the

tracing activation message to the MSC/VLR where the MS is located. When the traced MS

initiates services, the MSC notifies the BSC to perform tracing. When the MS is switched

over to a new MSC, location update is initiated. Then the HLR sends a tracing activation

message to the new MSC/VLR and the tracing task of the original MSC is complete.

When receiving the message of starting a tracing task from the MSC, the BSC traces

information about all the interfaces and then saves the information to the BAM. The

information is saved as a .tmf file, which is used for interface tracing on the BSC LMT. The

file can be browsed through the function of interface tracing review on the BSC LMT. When

browsing the information about a traced MS, you can choose a time segment and choose the

message field to be viewed through a message filter window.

The BSC supports a maximum of 64 tracing tasks (including single-MS signaling tracing,

interface signaling tracing, and end-to-end MS signaling tracing tasks). There should be at

least 16 end-to-end MS signaling tracing tasks. If the number of existing end-to-end MS

signaling tracing tasks reaches or exceeds 16, determine whether the total number of tasks

reaches the upper threshold when creating an end-to-end MS signaling tracing task. If the

total number does not reach the upper threshold, you can create more tasks. If the total

number reaches the upper threshold, task creation fails.

Enhancement

None

Dependency





336

None




None


The M2000 and the CN must support this feature.

WOFD-190600 GBSS Enhanced Subscriber Tracing

WOFD-191400 G&U CS Subscriber Tracing

9.1.4 GBFD-510901 GSM/3G Neighboring Cell Automatic Optimization

Availability


Summary

By using the Nastar, a network optimization tool, you can find out the missing or redundant

neighboring 2G/3G cells of the GSM serving cell.

Benefits

This feature helps optimize the existing network, increase intra-system and inter-system

handover success rate, optimize the GSM network performance, and improve the user

experience.

Description

Assuming that the operator can provide both the 2G network and the 3G network, the 3G

network can be the WCDMA network or the TD-SCDMA network, if the 3G cells are

configured as the neighboring cells of the 2G cells and the neighboring cell relationships are

configured properly, the quality of the GSM network can be improved and the user can enjoy

abundant 3G services. If the neighboring cell relationships are configured improperly, there

are missing or redundant neighboring cells. The redundant neighboring cells make the MS

cannot quickly search for the useful cells. If the required neighboring cells are not configured,

some areas may not be covered, affecting the handover success rate.

This feature should be supported by the MS, BSC, M2000, and Nastar. The M2000 sends the

list of cells whose neighboring cells should be optimized, the list of neighboring 2G/3G cells

that should be measured by the cells, and the related measurement parameters to the BSC.

Then, the BSC regularly sends the information about the neighboring 2G/3G cells to the MS.

After the MS measures a neighboring cell, the information about the neighboring 2G/3G cell

is sent to the BSC through the measurement reports. The BSC records the neighboring cell

information to the traffic statistics and sends the statistics to the M2000. The Nastar obtains

the statistics from the M2000 and analyzes the statistics to obtain the missing and redundant

neighboring cells as shown in the following figure.




337

Huawei BSS supports two types of neighboring 3G cells: WCDMA neighboring cells (FDD

neighboring cells) and TD-SCDMA neighboring cells (TDD neighboring cells). One serving

cell supports only one type of neighboring cell.

Enhancement

None

Dependency


None




None


This feature should be supported by the M2000 and Nastar, and depends on the following

features:

GNFD-200020 GSM Neighboring Cell Analysis

GNFD-200090 GSM Frequency Analysis

WOFD-270100 Data Collection of Neighboring GBSS Cells

This feature can be enabled only when the related features of the GBSS and Nastar are

bought.




338

9.2 Visualization & Data Collection

9.2.1 GBFD-511701 Radio Measurement Data Interface for Navigation

Availability


Summary

After this feature is enabled, the BSC sends radio measurement data to the Vendor Network

Probe (VNP) through a specified interface, and the VNP sends the data to a navigation service

provider, for example, TomTom. Based on analysis of the radio measurement data, the

navigation service provider provides traffic and congestion information for subscribers.

Benefits

With this feature, the BSC can provide radio measurement data to help telecom operators and

navigation service providers jointly deploy navigation services.

Description

Based on TCP/IP, the BSC reports radio measurement data to the VNP through a specified

interface, which is a private interface currently.

The radio measurement data is reported to the VNP upon any of the following events:

A subscriber accesses a cell under the BSC.

The TA changes.

A cell reselection occurs.

A call connection is released.

An incoming or outgoing BSC handover occurs.

The collection unit (CU) of the navigation service provider then collects radio measurement

data from the VNP.

Enhancement

None

Dependency


None


None





339

None


To support this feature, the BSC can be connected to Huawei Nastar-TS V100R001C00 or

Ericsson VNP. Ericsson VNPs use a message format of Category3 or later versions. Huawei

VNPs use a message format of Category4 versions.




Page 340 of 362

A Acronyms and Abbreviations

Numerics

3G 3 rd Generation Mobile Communication System

3GPP2 3rd Generation Partnership Project 2

8PSK 8 Phase Shift Keying

A

AAL ATM Adaptation Layer

AB Access Burst

AbisPC Abis interface Port Control

ACCH Associated Control Channel

ACS Active Codec Set

AEC Acoustic Echo Cancellation

AFC Automatic Frequency Correction

AGCH Access Grant Channel

AGT Agent

AICP A Interface Common Procedure

ALC Automatic Level Control

ALM Alarm

AMR Adaptive Multi Rate

AMRFS Adaptive Multi Rate Full Speed

AMRHS Adaptive Multi Rate Half Speed

ANR Automatic Noise Restraint

APM Advanced Power Module

APN Access Point Name




341

APP Application

APS Automatic Protection Switchback

ARP Address Resolution Protocol

ARQ Automatic Request for retransmission

ATM Asynchronous Transfer Mode

ATT Attach-Detach allowed

B

BA BCCH Allocation

BAM Back Administration Module

BBU Baseband Control Unit

BCCH Broadcast Control Channel

BEP Bit Error Probability

BER Bit Error Rate

BFD Bidirectional Forwarding Detection

BG Border Gateway

BIU Base station Interface Unit

BKP Backplane Board

BM Basic Module

BMACT Basic Module Active Codec Type

BMRC BM Resource Control

BOM Bill Of Materials

BQ Bad Quality

BR Backward Reporting

BSC Base Station Controller

BSCOM BSC O&M

BSIC Base Station Identity Code

BSSAP Base Station Subsystem Application Part

BSSAP+ Base Station Subsystem Application Part Plus

BSSGP Base Station System GPRS Protocol

BTS Base Transceiver Station

BTSCP BTS Common Processing

BTSOM BTS O&M




342

BTSTRC BTS Transmission Resource Control

BVC BSSGP Virtual Connection

BVCI BSSGP Virtual Connection Identifier

C

CACS Common Active Codec Set

CAPEX Capital expenditures

CBC Cell Broadcast Center

CBCH Cell Broadcast Channel

CBE Cell Broadcast Entity

CBIP Cell Broadcast Interface Process

CBSC CDMA2000 Base Station Controller

CCB Call Control Block

CCCH Common Control Channel

CCU Channel Codec Unit

CDB Cell Broadcast Database

CDU Combining and Distribution Unit

CECCM CEll CCM process

CECHM CEll Channel Management

CEGPRS Cell GPRS Processing

CELP Code-Excited LPC

CESP Cell Service Process

CGI Cell Global Identifier

CHR Call History Record

CI Cell Identify

CI Cell Identity

CIC Circuit identification code

CIU Circuit Interface Unit

CM Configuration Manage

CMI Codec Mode Indication

CMR Codec Mode Request

CPRI Common Protocol Radio Interface

CPUX xpu CPU eXtended




343

CRC Cyclic Redundancy Check

CRDLC Call Radio Link Control

CS Coding Scheme

CSD Circuit Switched Data

CV Countdown Value

CW Call Wait

D

DACS Distant Active Codec Set

DBAPI DataBase API

DBG Debug

DBMI DataBase Management Interface

DBUS Data-BUS

DCS 1800MHz Digital Cellular System 1800MHz

DHCP Dynamic Host Configuration Protocol

Diffserv Differentiated Services

DOPRA Distributed Object-oriented Programmable Realtime Architecture

DPU Data Process Unit

DRFU Double Radio Filter Unit

DRX Discontinuous Reception

DSCP DiffServ Code Point

DSPC DSP for transCoder

DSPI DSP for Integrated

DSPOM DSP O&M

DSPOM_AGT DSP OM Agent

DSPP DSP for Pcu

DT Debug Terminal

DTAP Direct Transfer Application Part

DTCB Distance To Cell Board

DTM Dual Transfer Mode

DTM Dual Transfer Mode

DTMF Dual-Tone Multi-frequency

DTX Discontinuous Transmission




344

E

ECSD Enhanced Circuit Switched Data

ECT Explicit Call Transfer

EDA Extended Dynamic Allocation

EFR Enhanced Full Rate

EFR Enhanced Full Rate

E-GSM Extended GSM-900 Band (includes Standard GSM-900 band)

EICC Enhanced Interference Counteract Combining

EML Extended Operation and Maintenance Link

EM-layer Element Management-layer

eMLPP Enhanced multi-level precedence and preemption service

EMR Enhanced Measurement Report

ES Errored Second

ESL Extend Signaling Link

ESR Errored Second Ratio

ETHERNET

OAM

ETHERNET OAM

ETRAU EGPRS TRAU

F

FACCH Fast Associated Control Channel

FAI Final Ack Indicator

FBI Final Block Indicator

FCS Frame Check Sequence

FDR Frequency Domain Reflectometer

FE Fast Ethernet

FEC Forward Error Correction

FER Frame Erase Ratio

FER Frame Erase Ratio

FH Frequency Hopping

FIR Finite Input Response

Flex Abis Flex Abis




345

FM Forward Monitoring

FN Frame Number

FR Frame Relay

FR Full Rate

FR AMR Full Rate AMR

FS Full Speed

FTP FILE TRANSFER PROTOCOL

FTPS FTP Over SSL

FUC Frame Unit Controller

G

Gb Gb interface

GBSC GSM Base Station Controller

GBSS GSM Base Station Subsystems

GDPUC GDPU for transCoder

GDPUX GDPU for eXtensible use

GE Gigabit Ethernet

GEHUB GSM E1/T1 High level Data Link Control Unit for aBis

GEIUB GSM E1/T1 Interface Unit for aBis

GEPUG GSM E1/T1 Packet Unit for Gb

GFGUA GSM FE/GE electronic interface Unit for A

GFGUB GSM FE/GE electronic interface Unit for Abis

GFGUG GSM FE/GE electronic interface Unit for Gb

GGCU GSM General Clock Unit

GGOUA GSM GE optical interface Unit for A

GGOUB GSM GE optical interface Unit for Abis

GMSK Gaussian Minimum Shift Keying (modulation)

GOMU GSM Operation and Maintenance Unit

GPRS General Packet Radio Service

GPS Global Position System

GRFU GSM Radio Frequency Unit

GRLM GPRS Radio Link Management

GRRM GPRS Radio Resource management




346

GSCU GSM Switching and Control Unit

GSM-R Railways Global System for Mobile Communication

GSN Gigabyte System Network

GTMU GSM Timing and Main control Unit

GTNU GSM TDM switching Network Unit

GTRAU GPRS TRAU

GTRAUE GPRS TRAU Enhancement

GTRAUIP GPRS TRAU IP transmission

GUI Graphical User Interface

GXPUM GSM eXtensible Processing Unit for Main service

H

HDLC High-Level Data Link Control

HLR Home Location Register

HMC High Multislot Classes

HR Half Rate

HR AMR Half Rate AMR

HS Half Speed

HSCSD High Speed Circuit Switched Data

HTTP Hypertext Transfer Protocol

HubBTS Hub Base Transceiver Station

I

IACS Immediate Active Codec Set

IBCA Interference Based Channel Allocation

ICB Inner Combiner bypass

ICC Interference Rejection Combining

ICMP Internet Control Messages Protocol

IDC Instance Distribution Control

IMEI International Mobile Equipment Identity

IMSI International Mobile Subscriber Identity

IP Internet Protocol

IR Incremental redundancy




347

ISI Inter-Symbol Interference

IWF Interworking Function

K

KPI Key Performance Index

L

L3IF Layer-3 Interface

LA Link adaptation

LAC Location Area Code

LACS Local Active Codec Set

LAI Location Area Identity

LAN Local Area Network

LAPD Link Access Protocol on D channel

LLC Logic Link Control

LMT Local Maintenance Terminal

LRM Local Resource Management

M

M3UA MTP3 User Adaptation Layer

MA Mobile Allocation

MAC Medium Access Control

MACS Maximum number of Codes Modes in the Active Codec Set

MAIO Mobile Allocation Index Offset

MCS Modulation and Coding Scheme

MGW Media Gateway

MML Man-Machine Language

MNC Mobile Network Code

MOS Mean Opinion Scores

MPTY MultiParty

MR Measurement Report

MSC Main Switching Center

MSIC MS Instance Control

http://en.wikipedia.org/wiki/Location_Area_Identity




348

MSIP MS Instance Processing

MSISDN Mobile Station International ISDN Number

MTBF Mean Time Between Failures

MTLS Mapping and Transfer between LAPD entity and Service entity

MTP2 Message Transfer Part 2

MTP3 Message Transfer Part 3

MTSS Mapping and Transfer between SCCP entity and Service entity

N

NACC Network Assisted Cell Change

NAT Network Address Translation

NCH Notification Channel

NLN Notification List Number

NM Network Management

NMS Network Management System

NRI Network Resource Identifier

NS Network Service

NSE Network Service Entity

NSEI Network Service Entity Identifier

NSS Network Subsystem

NSVC Network Service Virtual Connection

O

OACS Optimized Active Codec Set

OMC Operations & Maintenance Centre

OML Operation and Maintenance Link

OPEX Operating Expense

P

PACCH Packet Associated Control Channel

PAGCH Packet Access Grant Channel

PARC Platform of Advanced Radio Controller

Pb PCU-BSC interface link




349

PBCCH Packet Broadcast Control Channel

PBGT Power Budget Handover

PBIP Pb Interface Processing

PBT Power Boost Technology

PCCCH Packet Common Control Channel

PCH Paging Channel

PCM Pulse Code Modulation

PCS 1900MHz Personal Communications Service 1900MHz

PCU Packet Control Unit

PDCH Packet Data Channel

PDH Plesiochronous Digital Hierarchy

PDTCH Packet Data Traffic Channel

PDU Power Distribution Unit

PGC Paging Control

P-GSM Primary GSM-900 Band

PIU Packet Interface Unit

PLMN Public Land Mobile Network

PMU Power Management Unit

PoC Push to Talk over Cellular

PPCH Packet Paging Channel

PQ Priority Queue

PRACH Packet Random Access Channel

PS Packet Switch Domain

PSI Packet SI Status

PSU Power Supply Unit

PT Payload Type

PTCCH Packet Timing Advanced Control Channel

P-TMSI Packet-Temporary Mobile Station Identity

PTP Point-To-Point

PTRAU Packet Transcoder/Rate Adaptor Unit

PTT Push-To-Talk

PTU Packet Transmission Unit

PVC Permanent Virtual Connection




350

Q

QoS Quality of Service

QTRU Quadruple Transmission Receiver Unit

R

RACH Random Access Channel

RC Resource control & Common procedure

RFC Request for Comments

RFU Radio Frequency Unit

RIM Reference Information Manager

RLC Radio Link Control

RNC WCDMA Radio Network Controller

RPE-LTP Regular Pulse Excitation-Long Term Prediction

RQI Radio Quality Indicator

RR Radio Resources

RRBP Relative Reserved Block Period

RSL Radio Signaling Link

RTCP Real-Time Transport Control Protocol

RTP Real-Time Transport Protocol

RX Reception

S

SACCH Slow Associated Control Channel

SAIC Single Antenna Interference Cancellation

SAPI Service Access Point Identifier

SCCP Signaling Connection Control Part

SCH Synchronization Channel

SCTP Stream Control Transmission Protocol

SCU Switch Control Unit

SDH Synchronous Digital Hierarchy

SESR Severely Errored Second Ratio

SGSN Serving GPRS Support Node

http://www.google.cn/url?q=http://www.javvin.com/wireless/SCH.html&ei=wVy7ScqpBJTq6QOF3fTaBA&sa=X&oi=spellmeleon_result&resnum=1&ct=result&cd=1&usg=AFQjCNHE-PMOdOClIat6XKhZW3OR0cBokQ




351

SID Silence Descriptor

SIGTRAN Signaling Transport

SMC Short Message Centre

SMLC Serving Mobile Location Center

SMS Short Message Service

SMSCB Short Message Service Cell Broadcast

SONET Synchronous Optical Network

SP Service Provider

SPHY Single PHY

SSL Security Socket Layer

STP Signaling Transfer Point

T

TA Timing Advanced

TBF Temporary Block Flow

TC TransCoder

TCEC The TRAN Circuit Emulation Card

TCH Traffic Channel

TCHF Traffic Channel Full rate

TCP/IP Transfer Control Protocol /Internet Protocol

TD-SCDMA Time Division-Synchronous Code Division Multiple Access

TEI Terminal Endpoint Identifier

TFI Temporary Block Flow Identifier

TFO Tandem Free Operation

TGPU TRAN GBTS Package Process Unit

THP Traffic handle Priority

TLLI Temporary link level identity

TLS Transport Layer Security

TMN Telecommunication Management Network

TMSI Temporary Mobile Subscriber Identifier

TMU Timing/transmission and Management Unit

TNU TDM switching Network Unit

TOP TDM Over Packet




352

TPEC The TRAN Packet over E1/T1 Card

TRAU Transcoder & Rate Adaptation Unit

TRAUE TRAU Enhancement

TRAUIP TRAU IP transmission

TRC Trace

TrFO Transcoder Free Operation

TRM Transport Resource Management

TRU Transmission Receiver Unit

TRX Transceiver

TSU TDM Switching network Unit

TSYN TRAU Synchronization Unit

U

UDP User Datagram Protocol

UMTS Universal Mobile Telecommunications System

UOIP User traffic Data Over IP

UOP User Traffic Data Over Packet

USCU Universal Satellite card and Clock Unit

USF Uplink Status Flag

V

VAD Voice Activity Detector

VBS Voice Broadcast Service

VGCS Voice Group Call Service

VISP Versatile IP and Secure Platform

VLAN Virtual LAN

VLR Visitor Location Register

VoIP Voice over IP

VPN Virtual Private Network

VQI Voice Quality Index

W

WAN Wide Area Network




353

WBBP WCDMA Baseband Processing unit

WCDMA Wideband CDMA

WFQ Weighted Fair Queuing

WMPT WCDMA Main Processing Transmission unit

WRED Weighted Random Early Detection

WRR Weighted Round Robin

X

XPUX XPU eXtended

gbss14.0 optional feature description

Documents

huawei trademarks

huawei proprietary

huawei industrial base

purchased scope

purchased products

automatic noise restraint

automatic level control

usage scope