performance troubleshooting -ps - throughput v0.1

BSS Performance Troubleshooting Instructions

Throughput

Version 0.1

2 Copyright 2007 Nokia Siemens Networks.All rights reserved.

document description

Title and version Performance troubleshooting instructions - BSSReferenceTarget Group NPO engineers (working in NOA projects)Technology and SW release

2G, 2.5G

Related Service Items

Radio network optimization / Capacity Extension Management

Service Item numberAuthor Karri SunilaDate -Approver Eric Kroon

CHANGE RECORD

This section provides a history of changes made to this document

VERSION DATE EDITED BY SECTION/S COMMENTS

0.1 17.03.2010 Karri Sunila ALL First draft:

Copyright © Nokia Siemens Networks. This material, including documentation and any related computer programs, is protected by copyright controlled by Nokia Siemens Networks. All rights are reserved. Copying, including reproducing, storing, adapting or translating, any or all of this material requires the prior written consent of Nokia Siemens Networks. This material also contains confidential information which may not be disclosed to others without the prior written consent of Nokia Siemens Networks.


Table of Contents

Table of Contents......................................................................................3

1. Purpose and Scope....................................................................4

2. Throughput.................................................................................52.1 Radio resource management..................................................................................52.2 Throughput KPIs.....................................................................................................62.3 Referencing KPIs to be checked.............................................................................72.4 Referencing features.............................................................................................11

3. Troubleshooting.........................................................................113.1 Alarms...................................................................................................................113.2 Quality / Interference.............................................................................................113.3 Coverage...............................................................................................................123.4 Connectivity capacity............................................................................................133.5 HMC and EDA.......................................................................................................173.6 Parameters............................................................................................................18

4. References...............................................................................19


1. Purpose and ScopePurpose:

This document is an optimization guideline with the purpose to instruct NPO engineers working in NOA projects to deliver performance troubleshooting.

This document is meant for INTERNAL USE ONLY

Scope:

The scope of the document is the following:

To show how to troubleshoot cells to improve certain KPIs.

Note! All the networks are different and thus is heavily recommended to analyze network properly before optimization. Also properly optimization strategy should be created, will it be better to use special cell level optimized parameter values and loose control of the network or use some general (not cell level optimized) values.


2. ThroughputThroughput indicates the impact of radio link quality on net data rate per used timeslot considering retransmissions and coding scheme selection Performance of PS connections is very much dependent on the radio conditions in terms of C/I ratio.

The radio conditions determine a coding scheme used during the transmission and the number of retransmissions caused due to bad radio reception. The basic link performance is determined by the GERAN specifications that define the radio channel structure and transmission techniques such as modulation, channel coding and interleaving.

The user experienced throughput is influenced by various factors like: use of frequency hopping, frequency reuse, load, site-to-site distance, fading profile, etc.

2.1 Radio resource managementGPRS radio resource management in BSC involves two processes: division of radio timeslots between circuit switched and packet switched timeslot territories on the one hand, and channel allocation for individual MSs within the PS territory on the other hand. Division of radio timeslots into territories means that BSC selects the radio timeslots that shall be used primarily for packet data traffic and which shall therefore be avoided in traffic channel allocation for circuit switched services. During channel allocation for individual MSs PCU assigns PS territory timeslots for GPRS TBFs.

The radio resource management function which is responsible for the CS/PS territory management also takes care of traffic channel allocation for circuit switched calls. PCU has its own radio channel allocation that takes care of allocating channels for GPRS TBFs. Up to seven uplink GPRS TBFs can share the resources of a single radio timeslot. Uplink and downlink scheduling processes are independent of each other, and for downlink up to nine GPRS TBFs can share the resources of a single radio timeslot.

To enable GPRS traffic in a cell, and to initiate the creation of the necessary PS territory, the operator has to first activate GPRS in the BSC with the cell-specific parameter GPRS enabled (GENA) and define which TRXs are capable of GPRS with the parameter GPRS enabled TRX (GTRX). To activate EGPRS, the operator uses the BTS-specific parameter EGPRS enabled (EGENA).

Only after the BSC has an update on the BTS parameters and other parameters indicating GPRS usage, does it count the number of default and dedicated GPRS timeslots in the BTS and select a TRX where it starts to establish the GPRS territory.

The BSC can upgrade or downgrade the number of radio resources allocated for GPRS use according to the varying needs of the circuit switched and GPRS traffic. These procedures are explained in detail in the following sections.

From figure below, GPRS territories can be seen:


BCCHTRX 1

TRX 2

TS

Circuit Switched Territory

Circuit / Packet Switched Territory

Dedicated GPRS

Capacity (%)

TS TS TS TS TS TS

TS TS TS TS TS TS TSTS

Territory downgrade forced by the Circuit Switched traffic

Territory upgrade in interval of Territory Upgrade Guard Time

Default GPRS capacity thresholdExtra GPRS capacity

Free time slots in Circuit Switched territory

Default GPRS Capacity (%)

2.2 Throughput KPIs As it was mentioned earlier, basic radio metwork optimization improve also throughput. The optimal GSM network from PSW services point of view has:

o As high signal level as possible It means that even the indoor signal level should be high enough to

have MCS9 for getting the highest data rate on RLC/MAC layer.o As low interference as possible

The aim of having high C/I is to avoid throughput reduction based on interference.

o Enough capacity Enough hardware capacity is needed to provide the required capacity

for PSW services in time. Both CSW and PSW traffic management should be harmonized with the layer structure and long term plans.

o As few cell-reselection as possible The dominant cell coverage is important to avoid unnecessary cell-

reselections in mobility. The prudent PCU allocation can help to reduce the inter PCU cell reselections.

Dominant cell structure can help to maximize the signal level and reduce the interference, too.

o Features All the features should be used which can improve the PSW service

coverage, capacity and quality in general.

Throughput can be analyzed with following KPIs:

o llc_3a Volume weighted LLC throughput

o llc_4a Volume weighted LLC throughput for GPRS

o trf_234 Average effective ACK EGPRS UL throughput per used TSL

o trf_236 Average effective ACK EGPRS DL throughput per used TSL

o trf_233c Average effective ACK GPRS UL throughput per used TSL

o trf_235b Average effective ACK GPRS DL throughput per used TSL


Typical reasons for Throughput problems are

o Poor radio conditions, Interference and bad coverage

o Too small GPRS/EGPRS territory size

o TSL allocation problems

o Transmission problems, for example incorrectly created EDAP

o Lots of cell reselections

2.3 Referencing KPIs to be checkedIn following chapters some KPIs, which should be monitored when analyzing throughput problems are mentioned

There are many times several reasons for KPI degradation, so all step should be checked to be sure that reasons for GPRS attach problems will be found.

2.3.1 Quality (ulq_2a,dlq_2a, Rx_Level_Statistics table)

Bad quality is typically measured as BER (bit error rate) or as FER (frame erasure rate). The FER Measurement provides the uplink frame erasure rate (UL FER) from each codec of each TRX in the BTS.. In this document quality (DL and UL) is measured using BER measurements.

Bad quality is effecting heavily on PS KPis. In this chapter it is shown how quality can be measured and how to analyze if quality is on reason which is causing PS KPI decreasing in the network. In Troubleshooting chapter more detailed information, how to analyze bad quality is described

RX level – quality distribution can be seen below. The distribution (lowest picture) shows that there are quite a lot bad quality samples which will cause problems in the network.

o Voice quality will be decreasedo PS quality (throughput ) will be decreasedo Dominance areas are not working properlyo Drops + HO failures will be increased


q0 q1 q2 q3 q4 q5 q6 q7-100dBm 10645 8516 6813 5450 4360 3488 2791 2232-95dBm 47043 37634 30108 24086 9865 7543 5643 2345-90dBm 56204 44963 35971 28776 16574 5676 845 65-80dBm 200863 160690 128552 102842 17654 3653 145 28-70dBm 12785 10228 8182 6546 456 112 24 23-47dBm 4583 1123 583 452 261 76 26 2

Bad interference problem → signal level good (<-80dBm) and sometimes no better cell available. If better cell available and quality samples are 4 or worse → HO (reason quality or interference, depends on the parameter) Interference is causing drops.

Really bad interference problem → signal level is really good (<-70dBm) and usually no better cell available → no HO → samples can be seen in the table. Interference is causing drops.

Situation is “network is working properly” If there are quality 4 or worse samples → quality HO. Most of the samples are q4 samples. If lots of q5..q7 samples → interference problem and interference must be analyzed / removed. If quality HOs but no q5..q7 samples → better cell is available → no interference problems. In these signal levels overlapping exists and if handover reason is no PBGT, it will be quality HO. By parameter amount of quality HOs can be adjusted




Bad quality samples due to signal level problems. If PBGT overlapping is not existing → lots of quality HOs + level HOs (margin are lower than in PBGT).

Not interference problem, more coverage problem.

DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7-100dBm 12057 2827 3108 3952 4783 6200 7013 8156-95dBm 44818 4811 5041 5866 6587 7223 7259 6781-90dBm 98587 7107 7400 8334 8470 8781 7825 6162-80dBm 225919 7450 7731 8445 7726 7441 5695 3369-70dBm 88708 1014 971 998 751 688 689 367-47dBm 15881 84 109 122 104 167 199 184

There are almost as much samples Q5 and Q7 samples as Q 4 samples → even interference is really bad or there is no better cell available ( no ho’s after bad quality samples). These kind of interference cells should be optimized, otherwise there are lots of drops etc

The curve in the graph below shows the relation between C/I and RLC/MAC data rate based on NTN measurement results The RxLev is –70 dBm, so the performance is limited by interference only (LA enabled).

C/I dependency (FTP Download on 2 TSLs)

0

20

40

60

80

100

120

36 34 32 30 28 26 24 22 20 18 16 15 14 13 12 11 10 9

C/I

kbp

s

RLC/MAC Data Rate (2M Download 2TSLs)


As it can be seen in the graph above the interference starts to be limiting factor from 24 dB. Between 24 and 14 dB there is a significant degradation in data rate and from 14 dB till 9 dB the Link Adaptation is choosing robust enough MCSs (MCS3 and MCS2) to stabilize the throughput on 20 kbps/TSL.

The curve in the graph above is based on averaged values from Application Tester logs.

2.3.2 Coverage (Rx_Level_Statistics table)

Bad coverage means that received signal level is near the (MS/BS) sensitivity level. Here the quality will be decreased due to bad signal level and like bad quality, this bad quality will cause user perceived problems.

Bad coverage, like bad quality, is effecting heavily on PS KPIs. If there are bad coverage dips in the cell, quality will be decreased and call will be dropped. In troubleshooting chapter more detailed information how to analyze bad coverage is described.

See picture below, bad coverage samples are due to bad coverage.

DL_q0 DL_q1 DL_q2 DL_q3 DL_q4 DL_q5 DL_q6 DL_q7-100dBm 7055 1398 1374 1906 2163 2003 1468 832-95dBm 20109 1307 1274 1161 694 332 211 84-90dBm 34531 1053 745 587 273 131 94 41-80dBm 107539 875 518 630 161 98 113 47-70dBm 177614 283 316 663 61 32 29 9-47dBm 58718 78 91 198 54 40 54 32

There are bad quality samples only due to signal level problems.

Note! It should be checked that there is no imbalance problems between UL and DL. Many times UL is the weaker one, so UL coverage should be also checked.

The target of this chapter is to show the effect of signal level on data rate. The sensitivity threshold of the receivers determines the MCSs used during the connections.

The figure below shows that if the signal level is less then around –90 dBm and there is not any interference, than the RLC/MAC throughput will be lower then 100 kbps (Nokia Test Network (NTN) result). The outdoor field strength in city environment is higher than –90 dBm, but the indoor performance can be lower many cases (moreover most of the PSW users are located inside the buildings).


RLC/MAC Data Rate (2 TSLs)

0

20

40

60

80

100

120

-74 -76 -78 -80 -82 -84 -86 -88 -90 -92 -94 -96 -98 -100 -102 -104

RxLev (dBm)

kb

ps

RLC/MAC Data Rate (2M Download on 2 TSLs)

The figure above shows the data rate dependency clearly based on signal level. The interference can further reduce the throughput with the same signal level.

2.3.3 Abis capacity

In addition, the end-user throughput can be reduced if there is no sufficient Abis capacity. The Abis interface is established between a BTS site and a BSC to transmit CS&PS traffic produced by each BTS cell of a given BTS site. The Abis interface can be composed of 1 or more PCM lines depending on a site configuration and traffic load. Each PCM slot consists of 4 Abis sub-channels, each with capacity of 16 kbit/s, that are used to transmit voice and data traffic (TCH/PDCH channels) as well as signalling traffic (LAPD links).

The radio timeslots are associated with the Abis sub-channels (16 kbps). Speech channels and (E)GPRS channels with CS1-2 and MCS1 require a single Abis sub-channel while (E)GPRS channels with coding schemes CS2-4, MCS2-9 require up to 5 Abis sub-slots for a single radio timeslot to preserve throughput rates.

In case of the Flexible Abis Allocation there are dedicated resources for LAPD links and the remaining resources are shared fully dynamically by CS/PS traffic. Within the Abis pool, which is dedicated to CS/PS traffic, the association of the radio timeslots with the Abis sub-slots is done dynamically, so common Abis resources are shared by voice and data traffic. Moreover, the dynamic association follows the link adaptation of a given (E)GPRS data transfer, e.g. switching from MCS-9 to MCS-6 due to radio conditions forces reallocation of Abis resources from 5 Abis sub-slots to 3 Abis sub-slots.

In the Dynamic Abis implementation, there is fixed association (mapping) between RTSL and Abis sub-channels. In this way, PS blocking is always avoided since a single Abis sub-channel has enough capacity to handle GPRS traffic with CS1-2 as well as EGPRS traffic with MCS1. On top of this permanent resource allocation, the EDGE dynamic Abis pool (EDAP) is created to guarantee throughput rates for EGPRS with high coding schemes: whenever RTSL requires more than 1 Abis sub-channel then BSC allocates the remaining capacity from the EDAP pool, e.g. MCS-9 requires 4 sub-channels from the EDAP pool in addition to the dedicated Abis sub-channel.


2.4 Referencing featureso GSM Feature Considerations

MultiBCF and Common BCCH RF and BB Hopping FR/HR/DR with AMR IUO/IFH

o (E)GPRS Feature Considerations NMO1 EPCR NCCR NACC Priority based QoS CS3-4 HMC EDA DTM Extended cell for (E)GPRS

3. TroubleshootingThere are many times several reasons for KPI degradation, so all step should be checked to be sure that reasons for dropped calls will be found.

3.1 AlarmsCheck that there are no any ** or *** active alarms. Connection to NetAct is needed.

3.2 Quality / InterferenceBad quality is the most common reason for KPI decreasing. Some troubleshooting steps to reduce interference are mentioned below.

If there are bad quality (q4…q7) samples more than 5%, there are bad quality problems. Also fewer samples can cause bad drop problems in the network. Accurate threshold level is difficult to set, because networks are so different.

o Rx_Level_satistics table can be used for quality/interference analysis

o If bad quality in good signal level,(>-75dB)

Frequency changes (new frequency plan) should be done. This is the worst situation, because no better cell available to make interference HO.

Interference HO threshold can be adjusted to for example -75dB to make the difference between quality HO and interference HO more clear


o If bad quality in signal level,(-75dB…..-100dB)

Frequency changes can be done to reduce interference Handover Threshold Parameters, level, quality, interference. Threshold

values and Px,Nx values can be adjusted Normally some overlapping exists, so HOs to adjacency, reasons

quality/Interference will happen. Checked that no missing adjacency cells. Missing neighbors can be

one reason for bad quality, serving areas are not working properly. If AMR feature can be used, Handover Threshold Parameters, level,

quality, interference. Threshold values and Px,Nx values can be adjusted little more loose.

o If bad quality in bad signal level,(<-100dB) Bad quality due to bad coverage. Improve coverage, see 3.3 Check also imbalance between UL and DL. Which coverage UL or DL

is more important to improve Parameters (Rx Lev Min Cell (SL), Rx Lev Access Min (RXP)) can be

adjusted to avoid call setups / HOs in very bad coverage.

o Broken components, quality results are strange, see picture below

Q4 samples are strange, no typical interference. More quality4 samples than quality3 samples. HW problem, after TRX reset TRX started to work properly.

If AMR feature available and if lots of quality samples in quality5, but not in quality6 or quality7,

3.3 CoverageBad coverage problems are usually indoor problems due to increased losses (walls etc). These can be outdoor problems also. When cell level coverage problems are analyzed, it is good to check from planning tool or map, what kind of area it is (urban, suburban etc)

Bad coverage like bad interference is causing lots of dropped calls. Some troubleshooting step, how to monitor / improve bad coverage are mentioned below.

If there are more than 5% bad coverage samples, these can cause lots of drops in the network. Accurate threshold for bad coverage is difficult to set, networks are so different.


o Rx_Level_satistics table can be used for coverage analysis

o If bad UL signal level,(<-100dB) samples . Check imbalance between UL and DL. If lots of UL imbalance, UL

coverage improvement can improve network performance.o Add MHA to improve UL coverageo Check that receiver is working properly, no broken components

o If bad DL signal level,(<-100dB) samples . Check imbalance between UL and DL. If lots of DL imbalance, DL

coverage improvement can improve network performance.o Check that transmitter is working properly, no broken

componentso Check that power parameter (PMAX) is correct

o If no imbalance and bad coverage Improve coverage by adding RF components

o Add more gain antennaso Use Flexi BTS o Add new sectoro Add new site

Parameters (Rx Lev Min Cell (SL), Rx Lev Access Min (RXP)) can be adjusted to avoid call setups / HOs in very bad coverage.

o Broken components (lots of sample <-100dB), see picture below

Almost all UL samples in bad coverage. DL is working fine => HW problems, broken combiner, TRX etc. No alarms.

3.4 Connectivity capacityThe connectivity optimization for maximum capacity is based on the proper set of CDEF and DAP size. To provide enough capacity for territory upgrade the 75 % utilization in the connectivity limits is recommended by NSN

PCU Connectivity capacity limits can be seen below, see figure. Note, utilization term is used even the configuration is not changing dynamically (BTS, TRX etc)

Outputs Max limit* Utilization Limit unitAbis channles (radio TSLs) 256 75% 192 TSLsEDAP pools 16 75% 12 pcsBTS (cell, segment) 64 75% 48 pcsTRXs 128 75% 96 pcs*PCU & PCU-S handle 128 radio TSLs only with S11.5

*PBCCH is not implemented

Outputs Max limit* Utilization Limit unitAbis channles (radio TSLs) 256 75% 192 TSLsEDAP pools 16 75% 12 pcsBTS (cell, segment) 64 75% 48 pcsTRXs 128 75% 96 pcs*PCU & PCU-S handle 128 radio TSLs only with S11.5

*PBCCH is not implemented


More detailed information, see referencs

Dynamic Abis consists of a pool of channels; Dynamic Abis Pool (DAP) also called as EGPRS Dynamic Abis Pool (EDAP), which is used for excess capacity required for RLC/MAC blocks that does not fit to standard 16kbps Abis channel.

For (E)GPRS the BSC needs the Packet Control Unit (PCU), which implements both the Gb interface and RLC/MAC protocols in the BSS. The PCU controls the GPRS radio resources and acts as the key unit in the following procedures:

o GPRS radio resource allocation and managemento GPRS radio connection establishment and managemento Data transfero Coding scheme selectiono PCU statistics

PCU utilization can be monitored online using MML script Step by step work instruction, how to run this report, can be found

from: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/380102155

Note! Territory size impact on amount of needed PCUs must be analyzedo If territory size too big, PCU capacity is statically reserved too much

3.4.1 Connectivity capacity - monitoring

EDAP capacity can be monitored / optimized with following KPIs:

o DL / UL MCS selection limited by EDAP (dap_7a, dap_8c) o DL / UL MCS selection limited by PCU (dap_9, dap_10)o Peak DL EDAP usage (c76004)o Peak UL EDAP usage (c76005)o UL TBFS WITHOUT EDAP RES (c76006)o DL TBFS WITHOUT EDAP RES (c76007)o DL TBFS WITH INADEQUATE EDAP RES(c76008)o UL MCS LIMITED BY PCU (c76019)o DL MCS LIMITED BY PCU (c76020)o Territory upgrade rejection due to lack of PCU capacity (blck_32)

Not too much capacity nor too less capacityo EDAP / PCU performance can be decreased due to Gb link sizeo UL/ DL Gb load: frl_7a/ frl_8a

This should be checked always with EDAP / PCU optimization

Note! If EDAP utilization is below 100 => increasing EDAP does not provide any help => PCU optimization needed

https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/380102155



As a rule of thumb the following estimation may be used to calculate number of E1’s

Nbr of TRX Amount of E1s12 TRX GSM / GPRS

9 TRX GSM / EGPRS

6 TRX GSM / Heavy EGPRS

18 TRX GSM / GPRS

15 TRX GSM / EGPRS

12 TRX GSM / Heavy EGPRS

24 TRX GSM / GPRS

21 TRX GSM / EGPRS

18 TRX GSM / Heavy EGPRS2 E1

1 E1

1.5 E1

3.4.2 Solution for reducing PS blocking

Total throughput is small due to two reasons

o Throughput per RTSL is small, so the total throughput is also small. This is mainly poor radio conditions, see 3.2 and 3.3

o Not enough available timeslots for data TBFs are shared, so throughput will be small

If PS blocking can be reduced, throughput will be improved => Less time for downloading => blocking will be reduced even more.

PS blocking can be reduced with following step:

o Check sleeping GPRS alarm, no transactions alarm Transmission alarms If alarms, analyze reason for alarms and make corrections

o Check data rate per RTSL If <30kbit/sec => signal level / interference problems => Basic GSM

optimization must be done. Better throughput => less PS blocking

o Check TBF sharing (tbf_37d,tbf_38d, RS_226) If lots of TBF/ TSL => check that CDED parameter <>0 Too much sharing => territory not big enough. If possible, add more

dedicated timeslots . Check also connectivity capacity, Territory size vs. EDAP size analysis

Territory size impact on amount of needed PCUs If territory size too big, PCU capacity is statically reserved too much

o Check Territory usage, run RS_239 Check downgrades due to CSW traffic and PSW rejects Add more dedicated timeslots for data if possible Check CS traffic vs CDED, CMAX Check counters below


0 1 2 3 4 5 6 7

Default territory

1174

1181

1180

1179

0 1 2 3 4 5 6 7

Default territory

1174

1181

1180

1179

o Check territory size (GPRS parameters) Check configuration => TRP / BFG parameters, which TRX is preferred CMAX =100% or other planned value Note! Territory and dual rate in same TRX => not good, should be

changedo Check BTS GPRS parameters

If no system default values, make corrections (with customer acceptance)

o Check HR usage, run RS_211 Optimize HR traffic Add more dual rate timeslots Optimize FRL/FRU parameters + other HR parameters

o HOC optimization Adjusting HO parameters

3.4.3 Gb

In the Gb interface, two different transport technologies can be used: Gb over frame relay or Gb over IP. Gb over IP has a higher overhead than Gbover frame relay. This has an effect on bandwidth usage.

The transmission solution for the Gb interface can be implemented indifferent ways. There is no single correct solution that could be used inevery planning case. The aim is to ensure that the Gb link is large enough to handle the short term peak traffic of any single EDAP. In addition to this, the target is to estimate that the Gb link is large enough to support simultaneous traffic of several EDAPs. This is highly dependent on the traffic distribution.

Gb Capacity can be monitored with frl_8a KPI. Accurate KPI values are always project specific. Values below are only typical values.

o Good value for frl_8a: < maximum received load table values, see table belowo Bad value for frl_8a: > maximum received load table values, see table below


901024

85896

75768

70640

68512

68384

61256

25128

Restricting Gb link utilisation

[%]

Gb bandwidth [kbps]

901024

85896

75768

70640

68512

68384

61256

25128

Restricting Gb link utilisation

[%]

Gb bandwidth [kbps]

Solutions for improving throughput (Gb related)

o In the Gb interface (both Frame Relay and Gb over IP), low downlink throughput may result from incorrect base station system GPRS protocol (BSSGP) flow control values.

See reference, Flow control parameters

o In Gb over Frame Relay, the dimensioning of the interface may also be a limiting factor; for example, the size of the Frame Relay bearer channel, or network service entity (NSE) division into NS-VC(s).

o In Gb over IP, a limiting factor may be user data protocol (UDP) packet dropping caused by a duplex mode mismatch on the Gb over IP configuration.

Note! Link to Gb over IP guideline can be found from IMS, see references

3.5 HMC and EDAHigh Multislot Classes increases GPRS/EDGE peak downlink throughput to 296 kbit/s (~250 kbps on 5 DL TSLs in practice)

o Supports 3GPP Release 5 High Multislot Mobiles

o Multi Slot Class 30 ... 45 Mobiles

o Maximum (Sum = 6): 5+1, 4+2 Timeslots DL+UL

Extended Dynamic allocation increases GPRS/EDGE peak uplink throughput to 236.8 kbit/s (~200 kbps on 4 UL TSLs in practice)

o With Class 1-12 mobiles, no EDA

o Maximum 4+1, 3+2 timeslots DL+UL

o With Class 1-12 mobiles and EDA

o Maximum 1+4, 2+3 timeslots DL+UL

o With High Multislot mobiles and EDA


o Maximum 2+4, 3+3 Timeslots DL+UL

So EDA is not only an access method to help the device to connect to the network on UL, but it allows increasing the UL Multislot usage, too.

3.6 ParametersSGSG / GGSN related documents can be checked from IMS.

KPI guidline for SGSNhttps://sharenet-ims.inside.nokiasiemensnetworks.com/Open/358507056

PS core optimization guildleline https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D395591264

PS core optimization training material. https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/411075236:

3.6.1 BS_CV_MAX

The most important functionalities of BS_CV_MAX parameter from network planning point of view is described in [1].

Recommended value: 9

Basically the BS_CV_MAX parameter should define the RLC round-trip delay in block periods.

If the BS_CV_MAX parameter has too high value (e.g. 15), then the mobile may ignore some nacks that would require retransmissions. So in some cases a block has to be nacked twice before the mobile is willing to make the retransmission. This may reduce the performance slightly.

On the other hand, if the BS_CV_MAX parameter is too large or if the mobile is not able to do accurate time stamping for the UL RLC blocks, then the mobile may ignore some negative acknowledgements that were received in the Packet UL ACK/NACK message. This may distort the ARQ procedure slightly.

If the BS_CV_MAX parameter is lower than the actual round-trip delay or if the mobile is not able to do accurate time stamping for the UL RLC blocks, then the mobile may transmit needless retransmissions after processing a Packet UL ACK/NACK message.

It is recommended to tune the BS_CV_MAX parameter so that the minimum value is searched with which the mobile does not send needless RLC retransmissions right after the processing of a Packet UL ACK/NACK message.


https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D395591264



After modification of this parameter it takes about 5 minutes for processes to get the new values. After 5 minutes disable and then re-enable GPRS in those cells where GPRS is active for the change to take effect.

More information, see reference 1


4. References

1 (E)GPRS Radio Networks – Optimization Guidelines v3.0https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970

2 Nokia Flexi EDGE Base Station Transmission Planning Guide https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/382286976

3 GERAN BSS13 EGPRS Optimization Guideline for Abis PCU and Frame Relayhttps://sharenet-ims.inside.nokiasiemensnetworks.com/Open/397142744

4 Update for Abis quality and signaling link load.ppt https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/390957363

5 Abis Signaling Optimization Work Instruction https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/368223476

6 Geran Capacity optimization guide – access transmission

https://sharenet-ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=413652220&objAction=Open&vernum=1&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dsrch%2ESearchCache%26cacheId%3D17042108

7 DTM Planning Theoryhttps://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/369783353

8 BSSGP Flow Control Optimization in GSM/GPRS networkshttps://sharenet-ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=375269236&objAction=Open&viewType=1&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dll%26objId%3D368241835%26objAction%3DBrowse%26viewType%3D1

9GERAN BSS13 EGPRS Optimization Guideline for Abis, PCU and Frame Relayhttps://sharenet-ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=397142744&objAction=Open&viewType=1&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dll%26objId%3D358201401%26objAction%3DBrowse%26viewType%3D1

10 Gb EDGE Dimensioning (in NED)

11The Gb over IP Planning Guideline:https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/365271297

https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/365271297

https://sharenet-ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=397142744&objAction=Open&viewType=1&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dll%26objId%3D358201401%26objAction%3DBrowse%26viewType%3D1






https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/369783353

https://sharenet-ims.inside.nokiasiemensnetworks.com/livelink/livelink?func=ll&objId=413652220&objAction=Open&vernum=1&nexturl=%2Flivelink%2Flivelink%3Ffunc%3Dsrch.SearchCache%26cacheId%3D17042108







https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970

performance troubleshooting -ps - throughput v0.1

Documents

radio conditions

radio channel structure

division of radio timeslots

bad radio reception

impact of radio link

channel coding

throughput kpis

document description