amr_nokia

Adaptive Multi Rate Codec SystemFeature Description

DN03298089Issue 5-0 en

# Nokia Corporation 1 (38)

BSC3120Nokia GSM/EDGE BSS, Rel. BSS12, SystemDocumentation

The information in this document is subject to change without notice and describes only theproduct defined in the introduction of this documentation. This document is intended for the useof Nokia's customers only for the purposes of the agreement under which the document issubmitted, and no part of it may be reproduced or transmitted in any form or means without theprior written permission of Nokia. The document has been prepared to be used by professionaland properly trained personnel, and the customer assumes full responsibility when using it.Nokia welcomes customer comments as part of the process of continuous development andimprovement of the documentation.

The information or statements given in this document concerning the suitability, capacity, orperformance of the mentioned hardware or software products cannot be considered binding butshall be defined in the agreement made between Nokia and the customer. However, Nokia hasmade all reasonable efforts to ensure that the instructions contained in the document areadequate and free of material errors and omissions. Nokia will, if necessary, explain issueswhich may not be covered by the document.

Nokia's liability for any errors in the document is limited to the documentary correction of errors.NOKIA WILL NOT BE RESPONSIBLE IN ANY EVENT FOR ERRORS IN THIS DOCUMENTOR FOR ANY DAMAGES, INCIDENTAL OR CONSEQUENTIAL (INCLUDING MONETARYLOSSES), that might arise from the use of this document or the information in it.

This document and the product it describes are considered protected by copyright according tothe applicable laws.

NOKIA logo is a registered trademark of Nokia Corporation.

Other product names mentioned in this document may be trademarks of their respectivecompanies, and they are mentioned for identification purposes only.

Copyright © Nokia Corporation 2006. All rights reserved.

2 (38) # Nokia Corporation DN03298089Issue 5-0 en

Adaptive Multi Rate Codec System Feature Description

Contents

Contents 3

Summary of changes 5

1 Adaptive Multi Rate Codec 71.1 Link adaptation 121.2 Channel allocation 14

2 System impact of Adaptive Multi Rate Codec 172.1 Requirements 172.2 Impact on transmission 202.3 Impact on BSS performance 202.4 User interface 212.4.1 BSC MMI 212.4.2 BTS MMI 212.4.3 BSC parameters 212.4.4 Alarms 232.4.5 Measurements and counters 232.5 Impact on Network Switching Subsystem (NSS) 302.6 Impact on NetAct products 302.7 Impact on interfaces 312.8 Impact on mobile terminals 312.9 Interworking with other features 32

3 Implementing Adaptive Multi Rate Codec 353.1 Activating Adaptive Multi Rate Codec 353.2 Deactivating Adaptive Multi Rate Codec 37



Contents

Summary of changes

Changes between document issues are cumulative. Therefore, the latest documentissue contains all changes made to previous issues.

Changes made between issues 5-0 and 4-0

Section System impact of Adaptive Multi Rate Codec has been updated with thefollowing information:

. impact on transmission with new BSC variants

. 107 AMR RX Quality Measurement

. interworking with Single Antenna Interference Cancellation

Section Activating Adaptive Multi Rate Codec has been restructured.

Changes made between issues 4-0 and 3-0

Information on AMR HR licensing added.



Summary of changes

1 Adaptive Multi Rate Codec

The Adaptive Multi Rate (AMR) codec, standardised for GSM during 1998-1999, optimises speech quality in various radio channel conditions by adapting itsbit rate allocation between speech and channel coding. This provides the nextstep in the improvement of speech quality in GSM after the introduction of theEnhanced Full Rate (EFR) codec in 1996, the first codec to provide wirelinespeech quality. The AMR codec brings further quality enhancements, especiallyin terms of high error robustness in the full rate channel. It also provides the firstcodec with quality comparable to wireline for the half rate channel in goodchannel conditions. All previous GSM codecs operate with fixed partitioningbetween speech and channel coding (error protection) bit rates. These bit rateshave been chosen as compromises between performance in error-free and high-error channels. The AMR codec operates in either the GSM full or half ratechannel and selects the optimum bit rate trade-off between speech and channelcoding, according to the channel quality, to deliver the best possible overallspeech quality. To achieve overall good speech quality, the quality degradationcaused by speech coding and the errors engendered by the transmission channelhave to be carefully balanced.

AMR is a technology that enables operators smoothly and cost-efficiently to addvoice capacity in their networks. In the Nokia AMR solution, this requires only asoftware upgrade. AMR is one of the voice capacity enhancement technologies(the others are: half rate, frequency hopping, intelligent frequency hopping,further development of handover algorithm).

AMR consists of eight different speech codec modes with a total of 14 channelcodec modes (see Table Channel and speech codec modes available for AMR).All the speech codecs are defined for the full rate channel, while the six lowestones are defined for the half rate channel. The net bit rate is 0.10 kbit/s (in-bandchannel). The channel coding bit rate (in-band) is 0.30 kbit/s.



Adaptive Multi Rate Codec

Table 1. Channel and speech codec modes available for AMR

Channelmode

Channelcodec

mode

Source coding bitrate, speech

Channel codingbit rate, speech

TCH/FR CH0-FS

CH1-FS

CH2-FS

CH3-FS

CH4-FS

CH5-FS

CH6-FS

CH7-FS

12.20kbit/s(GSMEFR)

10.20 kbit/s

7.95 kbit/s

7.40 kbit/s (IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

10.20 kbit/s

12.20 kbit/s

14.45 kbit/s

15.00 kbit/s

15.70 kbit/s

16.50 kbit/s

17.25 kbit/s

17.65 kbit/s

TCH/HR CH8-HS

CH9-HS

CH10-HS

CH11-HS

CH12-HS

CH13-HS

7.95 kbit/s(*)

7.40 kbit/s (IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

3.25 kbit/s

3.80 kbit/s

4.50 kbit/s

5.30 kbit/s

6.05 kbit/s

6.45 kbit/s

(*) Requires 16 kbit/s TRAU. Therefore it is not seen as a feasible codec modeand is not supported by Nokia BSS.

A mobile station must implement all the codec modes. However, the network cansupport any combination of them.

Each codec mode provides a different level of error protection through a differentdistribution between speech and channel coding.

The link adaptation process measures the channel quality. Depending on thequality and possible network constraints (for example network load), modeadaptation selects the optimal speech and channel codecs. The mobile station(MS) and the base transceiver station (BTS) both perform channel qualityestimation for their own receive paths. Based on the channel qualitymeasurements, the MS sends a Codec Mode Request (Mode requested to be usedin the downlink) to the BTS. This signalling is sent in-band, along with thespeech data. The in-band signalling has been designed to allow fast adaptation torapid channel variations.



Codec mode adaptation for AMR is based on received channel quality estimationin both MS and BTS, followed by a decision on the most appropriate speech andchannel codec mode to apply at a given time. In high-error conditions more bitsare used for error correction to obtain error robust coding, while in goodtransmission conditions a lower amount of bits are needed for sufficient errorprotection and more bits can therefore be allocated for the source coding.

An in-band signalling channel is defined for AMR that enables the MS and theBTS to exchange messages on applied or requested speech and channel codecmodes. The selected speech codec mode mentioned above is then sent to thetransmitting side by using the in-band signalling channel, where it is applied forthe other link. The BTS commands the MS to apply a particular speech codecmode in the uplink by Codec Mode Command. The MS sends a Codec ModeRequest (Mode requested to be used in the downlink) to the BTS. The BTS hasan option to override the MS' request. The codec mode in the uplink may bedifferent from the one used in the downlink, but the channel mode (full rate orhalf rate) must be the same.

Mobile stations must support all speech codec modes, although only a set of up to4 speech codec modes is used during a call. BSC supports all of speech codecmodes, except 7.95 kbit/s on HR channel, and it has one default set for eachchannel mode. The default codec sets also include a default set of decisionthresholds and hysteresis. The initial codec mode and codec set with thresholdsand hysteresis are transferred between network elements and MS by using theexisting layer 3 signalling. Only a few add-ons are needed.

EFR, AMR full rate (FR), and AMR half rate (HR) are application software in theBSC. You can use either AMR FR, AMR HR, or both.

AMR HR requires a valid licence in the BSC. For more information, see BSSLicensing.

Benefits of Adaptive Multi Rate Codec

GSM speech codecs (full rate - FR, half rate - HR and enhanced full rate - EFR)operate at a fixed coding rate. The channel protection (against errors) is alsoadded at a fixed rate. The coding rates are chosen as a compromise between thebest clear channel performance and robustness to channel errors.

The AMR system exploits the implied performance compromises by adapting thespeech and channel coding rates according to the quality of the radio channel.This gives better and clearer channel quality and better robustness to errors.These benefits are realised regardless of whether operating in full rate or half ratechannels.




Example

Consider the situation where the mobile is in a zone of the cell border where youhave a bad C/I (for example 7dB). With EFR you have a degradation of thequality of the speech due to interference. With AMR, however, similar qualitycan be achieved with a reduced number of speech coded bits which allows morebits to be used for error protection and correction (see Figure ETSI Mean OpinionScore test results for current EFR/FR and AMR FR).

Together with quality improvements, the need to enhance capacity by allocatinghalf rate channels to some or all mobiles in the network is also recognised. Theradio resource algorithm, enhanced to support AMR operation, allocates a halfrate or full rate channel according to channel quality and the traffic load on thecell to obtain the best balance between quality and capacity.

Example

Increase in capacity: in normal C/I condition two voice channels can use a singletimeslot in the case of Half rate coding (HR) with little or no compromise in voicequality compared to EFR (see Figure ETSI Mean Opinion Score test results forcurrent EFR/FR and AMR FR).

Optimal interworking with power control and handover algorithms together withenhanced quality measurements (FER Measurement feature) provides fullbenefits and interworking with prior Nokia capacity features including IntelligentFrequency Hopping (IFH).



Figure 1. ETSI Mean Opinion Score test results for current EFR/FR and AMRFR

1.0

2.0

3.0

4.0

5.0

No Errors 16 dB C/I 13 dB C/I 10 dB C/I 7 dB C/I 4 dB C/I

EFR

AMR FR

AMR Full Rate performance compared to

Full Rate EFR in Clean Speech

1.0

2.0

3.0

4.0

5.0

No Errors 19 dB C/I 16 dB C/I 13 dB C/I 10 dB C/I 7 dB C/I 4 dB C/I

FR

AMR HR

AMR Half Rate performance compared to

Full Rate in Clean Speech

MOS (Mean Opinion Score)

MOS (Mean Opinion Score)




1.1 Link adaptation

Link adaptation is the capacity of AMR feature to vary the codec used accordingto the link conditions. Both networks, for uplink, and MS, for downlink, measurethe radio conditions in each link and decide which codec to apply to each way.

Two different types of link adaptation algorithms are defined: codec modeadaptation and channel mode adaptation. The channel mode adaptation algorithmdecides whether speech can be handled by a full rate channel or by a half ratechannel according to the link conditions, whereas for the channel selected, thecodec mode adaptation algorithm decides which codec is the one that providesthe best speech quality for the current radio conditions. Because each codec has adifferent channel protection and speech encoding performance, the idea of thecodec mode adaptation is to select the codec that provides the best speech qualityfor the radio conditions that the receivers are submitted to.

Codec mode adaptation

There are two link adaptation (LA) modes; the standardised fast LA and theNokia-proprietary slow LA. Fast LA BTS allows in-band codec mode changes onevery other TCH frame, but in Nokia proprietary slow LA BTS allows in-bandcodec mode changes only on SACCH frame interval.

The choice of the LA mode is done on BSC-basis with the parameter Slow Amr

La Enabled: if it is set to N (default), fast LA is used; if it is set to Y, Nokia slowLA is used. With slow LA, BTS allows in-band codec mode changes only on theSACCH frame interval of 480 ms and this option gives better flexibility with HOand PC algorithms. During both LA modes, the BTS indicates the first and thelast used codec during the last measurement interval and the average quality. TheBTS commands the MS to apply a particular speech codec mode in the uplinkconnection, but the MS can only request the BTS to apply a particular speechcodec mode downlink, because the BTS has an option to override the MS'srequest (see Figure AMR Link Adaptation).

The codec mode bit rate, that is, the bit rate partitioning between the speech andchannel coding for a given channel mode, may be varied rapidly (see FigureExample of AMR Codec mode link adaptation). The codec mode can be switchedone up or one down at the time so that it is not possible to switch from the mode12.2 kbit/s to 4.75 kbit/s when for example the modes 5.9 kbit/s and 7.4 kbit/s areincluded to the mode set. Also, it should be noted that codec changes do not takeplace immediately after the Codec Mode Command/Request is sent: there is adelay until a frame is received with the new codec.

Codec mode adaptation operates independently on the uplink and downlink. It istransparent to the channel allocation and operates without of it. Control dependsmainly on measurements of the quality of the respective links.



Channel mode adaptation

The channel mode (FR or HR) is switched to achieve the optimum balancebetween speech quality and capacity enhancements. The uplink and downlink usethe same channel mode. The channel mode is selected by the network based onmeasurements of the quality of the uplink and downlink.

Figure 2. AMR link adaptation

DL channelquality

UL codeccommand

DL codec

UL channel quality 16 or 8kbit/s

DLcodec

ULadaptation

MS BTS T

DLadaptation




Figure 3. Example of AMR Codec mode link adaptation

1.2 Channel allocation

HR and EFR principles are applied with one exception: an AMR call may bestarted in full rate channel in a new cell. It depends on the parameter InitialAMR Channel Rate which has a default value Any Rate. This value means thatthe chosen channel rate is defined by taking into account the currently usedinformation (Channel Type IE, resource situation on radio interface, circuit pool,current channel rate, HO parameters). The other option is AMR FR which meansthat full rate channel is allocated despite the values of the currently usedinformation. If AMR FR codec is not present in the Channel Type element or itcannot be allocated (for example AMR FR set is disabled in the target cell),

7.95 kbit/s

12.2 kbit/s

6.70 kbit/s

5.90 kbit/s

C/I EFR operation AMR modeAMRC/I

30

25

20

15

10

5

00 5 10 15 20 25 30

Time[s]



allocation continues with the currently used information. The parameter is validin call setup (except in FACCH call setup), internal inter cell handover andexternal handover. The reason for this parameter is that quality may not besufficient for HR AMR call setup (radio measurement is done on SDCCH).

With the use of the TRP parameter, you can direct AMR calls primarily to non-BCCH TRX and non-AMR calls primarily to BCCH TRX.

Related topics

. Enhanced Speech Codecs: AMR and EFR in Nokia BSC/TCSM ProductDocumentation

. Activating and Testing BSS10004: AMR in Nokia BSC/TCSM ProductDocumentation




2 System impact of Adaptive Multi RateCodec

The system impact of Adaptive Multi Rate speech codec (AMR) is specified inthe sections below. For an overview, see Adaptive Multi Rate Codec.

For implementation instructions, see Activating Adaptive Multi Rate Codec.

AMR HR is an application software product and requires a valid licence in theBSC.

2.1 Requirements

Hardware requirements

Table 2. Required additional or alternative hardware or firmware

Network element HW/FW required

BSC No requirements

BTS No requirements

TCSM TCSM2 or TCSM3irequired.

SGSN No requirements



System impact of Adaptive Multi Rate Codec

Software requirements

Table 3. Required software

Network element Software releaserequired

BSC S10

All Nokia BSCs andTCSM2/TCSM3i withsoftware version S10onwards have fullAMR support, except7.95 kbit/s on HRchannel.

Nokia Flexi EDGEBTSs

EP1.0

Nokia UltraSiteEDGE BTSs

CX3.0 or later

Nokia MetroSiteEDGE BTSs

CXM3.0 or later

Nokia 2nd Gen.BTSs

Not supported

Nokia Talk-familyBTSs

DF6

Nokia Talk-family BTSshave AMR support forFR modes 4.75, 5.9,7.4, and 12.2 as wellas for HR modes 4.75,5.9, and 7.4 withsoftware version DF6.0onwards. With thisapproach, the linkadaptation between fullscale of FR modesand almost full scale ofHR can be achieved.



Table 3. Required software (cont.)

Network element Software releaserequired

Nokia PrimeSiteBTSs

DF6

Frequency Hopping isremoved if AMR isimplemented.

Nokia PrimeSite BTSAMR support is similarto that of Nokia Talk-family BTS. Due to thelimited DSP processor/memory capacity thefrequency hoppingfunctionality isremoved fromPrimeSite BTSs toenable this SWmodification. Thismeans that the lastPrimeSite SW releasesupporting frequencyhopping is DF5.0.

Nokia InSite BTSs Not supported

MSC M10

Nokia NetAct OSS3.1

NetAct Planner 5.0

SGSN No requirements

Table Required software shows the earliest version that supports AMR.

Frequency band support

The BSC supports AMR on the following frequency bands:

. GSM 800

. GSM 900

. GSM 1800

. GSM 1900




2.2 Impact on transmission

Table 4. Maximum number of TRXs in different BSC types with AMR FR andAMR HR

BSC TRXs with AMRFR

TRXs withAMR HR

BSC2i 512 256

BSC3i 660 660 330

BSC3i 1000 1000 500

BSC3i 2000 2000 1000

2.3 Impact on BSS performance

OMU signalling

No impact.

TRX signalling

The use of AMR HR adds to TRX signalling, compared to the use of AMR FR.This may require increasing the speed of the TRXSIG link from 16 kbit/s to 32kbit/s.

Impact on BSC units

Table 5. Impact of AMR on BSC units

BSC unit Impact

OMU No impact

MCMU No impact

BCSU No impact

PCU No impact

Impact on BTS units

No impact on BTS units.



2.4 User interface

2.4.1 BSC MMI

The following command groups and MML commands are used to handle AMR:

. Parameter Handling (WO)

. Base Transceiver Handling in BSC (EQ)

. Transceiver Handling (ER)

. Base Station Controller Parameter Handling in BSC (EE)

. Handover Control Parameter Handling (EH)

. Power Control Parameter Handling (EU)

. Adjacent Cell Handling (EA)

. Transcoder Configuration (WG)

. Licence and Feature Handling (W7)

For more information, see the MML Command Reference Manuals in NokiaBSC/TCSM Product Documentation.

2.4.2 BTS MMI

AMR cannot be managed with BTS MMI.

2.4.3 BSC parameters

FIFILE parameters

. AMR_CODEC_USED (for AMR FR)

For more information on FIFILE parameters, see PRFILE and FIFILE ParameterList in Nokia BSC/TCSM Product Documentation.

BSC radio network object parameters

. AMR Configuration In Handovers

. AMR Set Grades Enabled

. Initial AMR Channel Rate




. Lower Limit For FR TCH Resources

. Upper Limit For FR TCH Resources

. Slow AMR LA Enabled

. TCH Rate Internal Handover

BTS radio network object parameters

. AMR FR Codec Mode Set

. AMR HR Codec Mode Set

SEG-specific BTS radio network object parameters

. TCH Rate Intra-Cell Handover

Transceiver radio network object parameters

. TRX Half Rate Support

Handover control radio network object parameters

. Intra HO Threshold Rx Qual AMR FR

. Intra HO Threshold Rx Qual AMR HR

. Threshold DL Rx Qual AMR FR

. Threshold UL Rx Qual AMR FR

. Threshold DL Rx Qual AMR HR

. Threshold UL Rx Qual AMR HR

Note

In Nokia NetAct, the parameters Intra HO Threshold Rx Qual AMR FR andIntra HO Threshold Rx Qual AMR HR are BTS radio network objectparameters.

Power control radio network object parameters

. PC Lower Threshold Dl Rx Qual AMR FR

. PC Upper Threshold Dl Rx Qual AMR FR

. PC Lower Threshold Dl Rx Qual AMR HR



. PC Upper Threshold Dl Rx Qual AMR HR

. PC Lower Threshold Ul Rx Qual AMR FR

. PC Upper Threshold Ul Rx Qual AMR FR

. PC Lower Threshold Ul Rx Qual AMR HR

. PC Upper Threshold Ul Rx Qual AMR HR

Note

In Nokia NetAct, the power control parameters are BTS radio network objectparameters.

Adjacent GSM cell radio network object parameters

. AMR Target Cell Of Direct Access To Desired Layer Applied

Transcoder Configuration

. tc_pcm pool

For more information on radio network parameters, see BSS Radio NetworkParameter Dictionary in Nokia BSC/TCSM Product Documentation.

2.4.4 Alarms

There are no AMR-specific alarms in BSC.

2.4.5 Measurements and counters

The following measurements and counters are related to AMR.

1 Traffic Measurement

Table 6. Counters of Traffic Measurement

Name Number

FULL TCH SEIZ SPEECH VER 2 001109

FULL TCH SEIZ SPEECH VER 3 001110

HALF TCH SEIZ SPEECH VER 3 001113




Table 6. Counters of Traffic Measurement (cont.)

Name Number

FULL TCH SEIZ INT HO CH RATE 001116

HALF TCH SEIZ INT HO CH RATE 001117

FULL TCH SEIZ INTRA AMR HO 001182

HALF TCH SEIZ INTRA AMR HO 001183

TCH CALL REQ FOR AMR 001184

SUCCESSFUL AMR CODEC SET DOWNGRADES 001185

UNSUCCESSFUL AMR CODEC SET DOWNGRADES 001186

SUCCESSFUL AMR CODEC SET UPGRADES 001187

UNSUCCESSFUL AMR CODEC SET UPGRADES 001188

For more information, see Counters/Performance Indicators: 1 TrafficMeasurement in Nokia BSC/TCSM Product Documentation.

4 Handover Measurement

Table 7. Counters of Handover Measurement

Name Number

HO ATT FOR AMR TO HR 004142

HO ATT FOR AMR TO FR 004143

For more information, see Counters/Performance Indicators: 4 HandoverMeasurement in Nokia BSC/TCSM Product Documentation.

14 RX Quality Statistics Measurement

Table 8. Counters of RX Quality Statistics Measurement

Name Number

AMR FR CODEC MODE 1 ON UPLINK DIRECTION WITHRXQUAL 0

014021

AMR FR CODEC MODE 1 ON DOWNLINK DIRECTION WITHRXQUAL 0

014022

This is repeated for each mode up to mode 4 (mode 1 rxq0-rxq7, mode 2 rxq0-rxq7, mode 3 rxq1-rxq7, mode 4 rxq1-rxq7).



Name Number

AMR HR CODEC MODE 1 ON UPLINK DIRECTION WITHRXQUAL 0

014085

AMR HR CODEC MODE 1 ON DOWNLINK DIRECTION WITHRXQUAL 0

014086

This is repeated for each mode up to mode 4 (mode 1 rxq0-rxq7, mode 2 rxq0-rxq7, mode 3 rxq1-rxq7, mode 4 rxq1-rxq7).

Name Number

AMR CODEC MODE SETS 014149

If the AMR codec mode set varies in the network, the counters of 107 AMR RXQuality Measurement are used.

For more information, see Counters/Performance Indicators: 14 RX QualityStatistics Measurement in Nokia BSC/TCSM Product Documentation.

21 Radio Measurement Report

Table 9. Counters of Radio Measurement Report

Name Number

AMR UL 1 0210800

AMR DL 1 0210801

AMR UL 2 0210805

AMR DL 2 0210806

... ...

AMR UL 31 0210950

AMR DL 31 0210951

AMR UL 32 0210955

AMR DL 32 0210956

For more information, see Counters/Performance Indicators: 21 RadioMeasurement Report in Nokia BSC/TCSM Product Documentation.




51 BSC Level Clear Code (PM) Measurement

Table 10. Counters of BSC Level Clear Code (PM) Measurement

Name Number

INTRA HO TO AMR HR 051133

INTRA HO TO AMR FR 051134

For more information, see Counters/Performance Indicators: 51 BSC Level ClearCode (PM) Measurement in Nokia BSC/TCSM Product Documentation.

107 AMR RX Quality Measurement

Table 11. Counters of AMR RX Quality Measurement

Name Number

BTS ID 107000

TRX ID 107001

ID OF FREQUENCY GROUP 107002

TRX FREQUENCY 107003

RX TRX IN EXT AREA 107004

AMR FR 4.75 ON UPLINK DIRECTION WITH RXQUAL 0 107005

AMR FR 4.75 ON DOWNLINK DIRECTION WITH RXQUAL 0 107006

... ...





... ...





... ...





Table 11. Counters of AMR RX Quality Measurement (cont.)

Name Number



... ...





... ...





... ...





... ...





... ...



AMR HR 4.75 ON UPLINK DIRECTION WITH RXQUAL 0 107133

AMR HR 4.75 ON DOWNLINK DIRECTION WITH RXQUAL 0 107134

... ...









Name Number

... ...





... ...





... ...





... ...



SAIC AMR FR 4.75 ON DOWNLINK DIRECTION WITHRXQUAL 0

107213

... ...


107220


107221

... ...


107228


107229

... ...


107236


107237




Name Number

... ...


107244


107245

... ...


107252


107253

... ...


107260


107261

... ...


107268


107269

... ...


107276

SAIC AMR HR 4.75 ON DOWNLINK DIRECTION WITHRXQUAL 0

107277

... ...


107284


107285

... ...


107292


107293

... ...


107300





Name Number


107301

... ...


107308


107309

... ...


107316

For more information, see Counters/Performance Indicators: 107 AMR RXQuality Measurement in Nokia BSC/TCSM Product Documentation.

2.5 Impact on Network Switching Subsystem (NSS)

Information on AMR codec is delivered on the A interface. An AMR-supportingpool must be in use on the A interface.

For more information, see Feature 901: Enhanced A-interface Circuit Allocationin MSC documentation.

2.6 Impact on NetAct products

NetAct Administrator

No impact.

NetAct Monitor

No impact.

NetAct Planner

Utilisation of AMR can be modeled in GSM simulations in NetAct Planner. Formore information, see Planner documentation.



NetAct Radio Access Configurator

NetAct Radio Access Configurator (RAC) can be used to configure radionetwork parameters related to AMR. For more information, see BSS RNWParameters and Implementing Parameter Plans in NetAct documentation.

NetAct Reporter

NetAct Reporter can be used to create reports from measurements related toAMR.

NetAct Tracing

No impact.

2.7 Impact on interfaces

Impact on radio interface

No impact.

Impact on Abis interface

AMR codec information is delivered in the CHANNEL ACTIVATION andMODE MODIFY messages.

Impact on A interface

Information on AMR codec is delivered on the A interface. An AMR-supportingpool must be in use on the A interface.

2.8 Impact on mobile terminals

An AMR supporting MS is required.




2.9 Interworking with other features

Direct Access to Desired Layer/Band (DADL/B)

To support the 2nd generation BTSs in the AMR environment, DADL/B is usedto hand over AMR calls to co-located AMR capable cells during the call set-upphase. Both intra-BSC and inter-BSC DADL/B handovers are possible andpreferably inside one frequency band as the failure probability is higher withDADL/B handovers between bands. The figure below shows an example ofDADL/B.

Figure 4. DADL/B and prioritisation

The relationship between TCH assignment and DADL/B handover start:

1) DADL/B used to direct AMRmobiles to AMR capable cells

2) Prioritisation of AMR capablecells in handovers

2nd gen BTS

UltraSite(co-located)

2nd gen BTS

SDCCH

TCH



. If there are no TCHs available in the accessed cell when an AMR call isattempted, Directed Retry due to congestion, with or without queuing, ismade.

. If there are TCHs available in the accessed cell and there are adjacent cellsdefined as DADL/B handover target cells with the parameter AMR TargetCell of Direct Access to Desired Layer, the DADL/B handover isapplied. Adjacent cells are not verified according to the MS capabilities(single band, dual band, or tri-band), but they have to fulfill the currentsignal level requirements to be considered as a target cell for DADL/Bhandover. The current method for sorting the target adjacent cells is used.

. If no DADL/B handover target cells are defined, the TCH is allocated fromthe accessed cell and another speech codec than AMR is chosen.

Enhanced TRX priorisation

With the use of TRX Priority In TCH Allocation parameter, you can directAMR calls primarily to non-BCCH TRX and non-AMR calls primarily to BCCHTRX.

Common BCCH and Multi BCF

In segment environment, if the AMR codec set of the BCCH BTS of the cell isenabled or disabled, it must also be enabled or disabled in the other BTSs of thatcell.

The AMR FR and AMR HR codec sets can be disabled or enabled separately.

For more information, see Common BCCH and Multi BCF in Nokia BSC/TCSMProduct Documentation.

Intelligent Frequency Hopping and Intelligent Underlay-Overlay

The AMR-specific good and bad C/I thresholds are specified for the HR andAMR FR:

. super reuse good C/I threshold for AMR HR

. super reuse bad C/I threshold for AMR HR

. super reuse good C/I threshold for AMR FR

. super reuse bad C/I threshold for AMR FR

Current Nx and Px values of C/I thresholds are in use.




The new threshold values for the AMR HR also serve the basic HR. The currentgood and bad threshold pair (super reuse good C/I threshold and super reuse badC/I threshold) serves the basic FR.

With the new thresholds you can control which type of speech calls are preferredto enter the super layer cells. For example, AMR HR calls can be packed to thesuper layer in order to increase the capacity of regular layer cells (good value forAMR HR - 5 dB compared to the current value and good value for AMR FR + 5dB, for example).

Satellite Abis

AMR FR is supported with Satellite Abis, but AMR HR is not.

Single Antenna Interference Cancellation

When Single Antenna Interference Cancellation (SAIC) is used in the networktogether with AMR, the SAIC-specific counters are updated in AMR RX QualityMeasurement.



3 Implementing Adaptive Multi Rate Codec

3.1 Activating Adaptive Multi Rate Codec

Before you start

Make sure of the following before activating AMR:

1. Hardware is correctly installed and the A and Abis interfaces are created asinstructed in BSS Integration in Nokia BSC/TCSM ProductDocumentation.

2. HR channels are created to the cells that are used for testing AMR HR.

For more information on HR channel creation and activation, seeActivating and Testing BSS6115: Half Rate in Nokia BSC/TCSM ProductDocumentation.

3. A licence covering AMR HR is installed.

4. The MSC supports AMR and an AMR-supporting pool is in use on the Ainterface. For more information on implementing AMR in Nokia MSC, seeFeature 901: Enhanced A-interface Circuit Allocation feature activation inNokia MSC/HLR Product Documentation.

Testing AMR requires an MSC, BSC, TCSM, BTS, and two MSs.

Note

If the BTS does not support AMR, the FACCH call set-up with AMR will fail.

Steps

1. Change the AMR-specific control parameter AMR_CODEC_USED to'ON' (WOA).

2. Activate AMR HR (W7M, EQY).



Implementing Adaptive Multi Rate Codec

3. Modify the speech circuits.

After activating the feature, you need to create an AMR pool. You caneither create a new A interface pool for AMR or modify an existing pool tosupport AMR.

For more information, see instructions in BSS Integration, Creating the Ainterface, sections: Creating the transcoder devices/Creating the TCSM2 orCreating the TCSM3i, Creating the speech channels, and Modifyingspeech circuits in Nokia BSC/TCSM Product Documentation.

You must change the type of the first TC-PCM from FR to AMR. There aretwo alternative ways to do this: you can remove and add the speech circuitsduring the modification or the speech circuits can be transferredautomatically during the modification. The second way is simpler in thesense that it contains fewer MMI commands than the first one.

Note

The modification is possible only between types that use the same number ofbits in the Ater interface. In other words, the submultiplexing scheme must bethe same for the current and the new pool.

Choose one of the following:. Remove and add speech circuits during modification

a. Remove the speech circuits of the first TC-PCM from thecircuit group that contains circuits of the FR pool (CEC,RCR).

b. Modify the TC-PCM type (WGM).

c. Restart the TCSM unit (USU).

d. Add the speech circuits to the circuit group that containscircuits of the AMR pool (RCA, CEC).

. Modify circuits with automatic circuit transfer

a. Block the speech circuits of the TC-PCM (CEC).

b. Modify the TC-PCM type (WGM).

c. Restart the TCSM unit (USU).

d. Unblock the speech circuits of the TC-PCM (CEC).

4. Configure the BTS to have both HR and FR timeslots (ERS, ERM).



Note

Do not use DR timeslots.

5. Lock all HR timeslots in the TRX (ERS) and make a call with an AMRmobile.

Expected outcome

The AMR FR call is successful.

6. Unlock all HR timeslots and lock all FR timeslots in the TRX (ERS)and make a call with an AMR mobile.

Expected outcome

The AMR HR call is successful.

7. Create and start a measurement to confirm a successful call; optional(TPM, TPS).

In the case of AMR FR, the related BTS-specific counter of trafficmeasurement is 001110 FULL TCH SEIZ SPEECH VER 3. In the case ofAMR HR, the counter is 001113 HALF TCH SEIZ SPEECH VER 3.

Further information

. Adaptive Multi Rate Codec

. Deactivating Adaptive Multi Rate Codec

. Activating and Testing BSS10004: AMR in Nokia BSC/TCSM ProductDocumentation.

3.2 Deactivating Adaptive Multi Rate Codec

Purpose

If the AMR-capable pool is no longer needed, remove it as instructed in BSSIntegration, section Creating the A interface, but in the reverse order.Alternatively, you can modify the AMR pool as instructed in Activating AdaptiveMulti Rate Codec.



Implementing Adaptive Multi Rate Codec

Telecom support for AMR is switched off with the feature-specific controlparameters. The parameters become valid after five minutes, therefore a five-minute delay is needed before testing the deactivation.

Steps

1. Switch off the AMR_CODEC_USED parameter (WOA).

2. Deactivate the AMR HR (EQY, W7M).



amr_nokia

Documents