AMR Optimization Guidelines - Ver01.02 - Jan06.ppt

AMR Optimization Guidelines

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NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Executive Summary AMR is an important feature that can allow a real jump in the capacity of the network. The US operator had been forerunners in its deployment because of:

d e v Limited frequency band and increased number of GSM customers o m of the Nokia BSS Advanced deployment of the feature in the ANSI e version r software e b Advanced deployment of the AMR capable MS in the US market o t e d i l The following guidelines: s s experience of the authors in the daily i Had been written based on the h optimization of the AMRT in the AT&T Wireless network in the Los Angelesmarket Are mainly aimed to cover the BSS optimization aspects Contain also basic information about the NSS activation aspects

Conclusions of the document are that AMR optimization: Is a basic step of the AMR deployment Need a fair amount of field work (i.e.drive test) in order to have the feeling of the Air i/f behaviour Depends from the penetration of AMR capable MS AMR optimization Guidelines / Jan 16 2006 / Ver 01.01 / NOKIA CONFIDENTIALth

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NOKIA

References In order to write these guidelines the following documents had been used: NED Nokia internal and customer documentation Daily optimization documents from the Los Angeles AT&T Wireless market d e NMS Stats v o Trial / Test on customer network m Drive test re

e b o t e d i l s is h T

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Warning The authors of the guidelines have based their experience on the work in ANSI markets (US operators), so some of the assumptions can be reviewed if the reader is optimizing the AMR in ETSI markets.

e guidelines are Because of this part of the information contained in the following v o the following based on the daily work in the operator office (AT&T Wireless) m e document contains information that are NOKIA and r customer confidential.

d

e b o t e S10.5 capabilities. Nevertheless the The following guidelines are based on d the i labout the S11.0 features that will affect AMR authors have included also few slide s optimization is h T

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Version ReviewVersion Date Changes from previous Version Authors

01

September 5th 2004

-

Andrea Bonanomi, Umesh Dhawan

01.01

January 19th 2006

Risto Jurva

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Topics AMR Overview AMR SW and HW Requirements EFR and AMR Capable Phones AMR Activation AMR Parameter Setting for Channel & Codec Adaptation TRX Prioritization in TCH Allocation HO and PC in AMR AMR Parameter Overview Radio Link Timeout in AMR MaxCap Feature AMR Optimization Remarks FRTx / HRTx Optimization Trial HOC, POC, BTS Optimization Trial Drive Test in AMR Capacity and Coverage AMR KPIs and Network Doctor Reports AMR MML Commands AMR and Soft Channel Capacity Feature (S11.0) Attachments

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AMR Overview

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Before & After AMR Before AMR the GSM operator had available on the air interface: 2 different Channel Type (Full Rate & Half Rate) 2 different channel Coding (1 @ Full Rate & 1 @ Half Rate) With the introduction of AMR the GSM operator has available on the air interface: 2 Different Channel Type (Full Rate / Half Rate) 14 Different Channel Coding (8 @ Full Rate & 6 @ Half Rate) The reason of the introduction of 2 different Channel Types is Exploit where possible the capacity of the TRX Cope w/with temporary increase of traffic The reason of the 14 different Channel Coding is to use in every moment of the conversation the best trade off between Channel Coding and Speech Coding. Increased Speech Coding ~ Increased Voice Reconstruction Accuracy Increased Channel Coding Increased Robustness Good FER in poor C/I environment8 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

AMR Idea The AMR idea is based on the fact that in soft limited RF environments (poor C/I): Speech coding can be decreased in order to improve channel coding Overall result is an improved voice quality (in terms of FER) For AMR, the speech and channel coding data rates are dynamically adapted to best fit the current RF channel conditions. AMR consists on a family of codec with different Channel Coding operating in GSM Full Rate (FR) and Half Rate (HR). The aim is to improve channel (FR/HR) quality by adapting the most appropriate channel codec based on the current radio conditions. With AMR, the speech capacity is increased by using the half rate (HR) mode and still maintaining the quality level of current FR calls. The idea behind the AMR codec concept is that it is capable of adapting its operation optimally according to the prevailing channel conditions.

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AMR Codec GSM FR/EFR channel gross bit-rate is 22.8 kbps in GSM FR/EFR: 13 kbps /speech coding 9.8 kbps /channel coding Note that HR channel gross bit rate 11.4 kbps For AMR case, different codec use different bit rate to encode speech (source coding). The rest of the gross bit-rate is used for channel protectionChannel bit-rate (kbit/s)25 20 15 10 5 0

Channel coding Speech coding

Robustness

FR 12.2

FR 10.2

Speech QualFR 7.95

FR 7.4 FR 6.7 FR 5.9

FR 5.15

FR 4.75

HR 7.95

HR 7.4 HR 6.7 HR 5.9

HR 5.15

HR 4.75

AMR codec mode10 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Algorithms Related to AMR Codec Mode Adaptation Algorithm = Link Adaptation Algorithm -> It selects the best codec

Channel Mode Adaptation Algorithm -> It changes the channel rate between FR and HR codec

Set of Codecs Codec Mode Adapt. Channel Mode Adaptation AMR

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AMR CodecsVoice qualityFull Rate 12.2 10.2 7.95 7.4 6.7 5.9 5.15 4.75 7.4 6.7 5.9 5.15 4.75 7.95 Half rate

AMR codecs: 8 for FR and 6 for HR

AMR Full Rate performance compared to Full Rate EFR in Clean Speech MOS (Mean Opinion Score) 5.0 4.0 3.0 2.01.0 No Errors

6 dB gain in performanceEFR AMR FR16 dB C/I 13 dB C/I 10 dB C/I 7 dB C/I 4 dB C/I

Robustness New AMR family of codec tolerate 6 dB higher interference than current GSM EFR codec Can be directly utilized for higher capacity with Frequency Hopping Higher interference tolerance Reduced time slot occupancy

AMR Half Rate performance compared to Full Rate in Clean Speech MOS (Mean Opinion Score) Quality loss 5.0 of ~ 0.2 between AMR HR 4.0 and FR 3.0 2.0 AMR HR AMR FR

1.0 No Errors 19 dB C/I16 dB C/I 13 dB C/I10 dB C/I 7 dB C/I 4 dB C/I12 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

AMR Channel and Speech CodecChannel mode Channel codec mode CH0-FS CH1-FS CH2-FS TCH/FR CH3-FS CH4-FS CH5-FS CH6-FS CH7-FS CH8-HS TCH/HR CH9-HS CH10 -HS CH11 -HS CH12 -HS Source coding bitrate, speech Net bit rate, in-band channel 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s Channel coding bit-rate, speech 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 3.25 kbit/s 3.80 kbit/s 4.50 kbit/s 5.30 kbit/s 6.05 kbit/s Channel coding bit-rate, in - band 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.30 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s 0.10 kbit/s

12.20kbit/s (GSM/EFR) 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 7.95 kbit/s (*) 7.40 kbit/s (IS-641) 6.70 kbit/s 5.90 kbit/s 5.15 kbit/s

CH13 -HS 4.75 kbit/s 0.10 kbit/s 6.45 kbit/s 0.10 kbit/s (*) Requires 16 kbit/s TRAU. Therefore it is not seen as a feasible codec mode and will not be supported by Nokia BSS10 .

In high-error conditions more bits are used for error correction to obtain error robust coding, while in good transmission conditions a lower amount of bits is needed for sufficient error protection and more bits can therefore be allocated for source coding13 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Codec Mode (Link) Adaptation

Advanced

Codec Mode Adaptation or Link Adaptation (LA) is the algorithm that selects which codec has to be used each moment by the MS (in UL) or by the network (in DL direction) The basic AMR codec mode sets for MS and BTS are provided by BSC via layer 3 signaling Both the MS and the network implement their own independent LA algorithms There are two link adaptation (LA) modes: ETSI specified fast LA Inband codec mode changes on every other TCH frame = 40 msec Nokia proprietary slow LA Changes only every SACCH frame interval = 480 msec The suggested LA rate is the fast one. LA algorithms are vendor dependant / proprietary14 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Advanced Procedure for Codec Mode (Link) Adaptation4.-DL codec used

3.- Network decides which codec to use for DL

DL LA 1.-Which DL Radio Conditions?2.-Request a codec for DL

UL LA

2.-Command a codec for UL

1.-Which UL radio conditions? 3.-MS uses the codec commanded by the network for UL

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In-band SignalingCMI, CMC C MR , CMI

Advanced

SF 2

UL

SF 4CMR SF 6 CMR SF 3

CMR

CMR CMI

CMR CMI

CMR CMI

CMR

CMR CMI

SF 1 8 TDMA

CMI SF 5CMI SF 7 CMI

CMI

CMI

frames SF 2 CMI SF 4 CMI SF 6 CMISF 8 CMI

CMI

CMI CMC CMC

CMI CMC

CMI CMC

CMI CMC

DL

SF 1

SF 3

SF 9 SF 7 CMCSF 5 CMC CMC CMC

SF= Speech Frame CMC = Codec Mode Command CMI = Codec Mode Indicator16 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

time

CMR= Codec ModeRequest

Channel Mode AdaptationChannel Mode Adaptation is an HO algorithm that aims at select the correct channel rate (FR or HR).

Advanced

The selection of the channel rate depends on 2 main factors: load and quality

Codec Good Load Quality

FR FR

packing unpacking Bad Qualit y

HR HR

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AMR SW and HW Requirements in NOKIA

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Software & Hardware RequirementsNetwork Element NMS MSC TCSM BSC 2nd Generation BTS Talk Family Prime Site UltraSite MetroSite InSite Required Software NetAct OSS3.1 GSM 15 or GSM 13 + MSC paTCH + pool switching capability S10.5 TCSM Software to support Pool 23. S10.5 (S10.ED CD10.1 or above) Does not support AMR DF6 DF6 CX3.0-2A CXM3.0-2 Does not support AMR

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Software & Hardware RequirementsNetwork Element TCSM BSC 2nd Generation BTS Talk Family Prime Site UltraSite MetroSite InSite Required Hardware All existing transcoder hardware supports AMR. Existing TR12 cards support the new Pool 23 with no upgrade required. Both BSC2i and BSC3i support AMR. Does not support AMR AMR is supported, TRX need to be upgraded. AMR is supported, TRX need to be upgraded. AMR is supported, TRX need to be upgraded. AMR is supported, TRX need to be upgraded. Does not support AMR

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Codecs Supported in the NOKIA BTS Note that the codecs supported from the Nokia BTSs depends from the type of BTS These are the codecs supported from the different NOKIA BTSsBTS Talk Family Prime Site Ultrasite Metrosite AMR FR AMR HR

4.75, 5.90, 7.40, 12.2 kbps 4.75, 5.90, 7.40 kbps 4.75, 5.90, 7.40, 12.2 kbps 4.75, 5.90, 7.40 kbps All All All except 7.90 kbps All except 7.90 kbps

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AMR Capable MS

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AMR Implementation Status in Nokia PhonesAMR Phones in Deliveries (until 1H/2005, update with the period 2H/2005-1H/2006)

1100

2300

2600

2650

3200

3220

5140

6170

6220

6230

6260

6810

6820

7200

7270

7280

7260

7610

9300

9500

AMR will be implemented in all new Nokia high volume phones The AMR capable MS can be identified through the MS Capability NMS measurements (P_NBSC_MS_CAPABILITY table) and mapping the classmark23 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

AMR Activation

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4 steps for AMR Activation Step 1 = Check SW & HW MSC, BSC, BTS, TRXs need to be compliant w/ SW & HW requirements (cfr. Previous section) Step 2 = Pool 5 conversion on MSC

d e v o em pool 1 to pool 5. This shall Convert all existing MSC circuits (except 1 DS0)r from e be done 1 T-1 at a time to avoid traffic interruption. b o t e d Step 3 = Pool 23 conversion/creation i l s iscreate the new Pool 23 circuit. Note this will On the BSC either convert or h T Number . If converting an existing circuit, the require a new Circuit Groupcircuit must be deleted and recreated for this conversion. On the MSC either convert or create the new Pool 23 circuit. Make sure the CIC codes maTCH on both sides of the A-interface

Step 4 = Feature activation on BSC On BSC activate AMR ( ZWOC:2,619:A;)

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AMR Activation Process

Start

Implement PRFILE

Activate AMR on BSC

Create AMR Pook (23) on Transcoder

Create Speech cirucit (3) on MSC and BSC

Download Parameters on BSC

Unlock Speech circuitrs on MSC

End AMR Calls

SW

It is advised to carry out deployment per BSC at a time It is always good practice to update all BTSs with latest

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Implement PRFILE Implement PRfile on BSCs

AMR-HR Capabilities

W7I:FEA,FULL:FEA=1,;FEATURE INFORMATION: ---------------------------------------------FEATURE CODE:..............1 FEATURE NAME:..............amr_hr-c FEATURE STATE:.............ON FEATURE CAPACITY:..........1000 COMMAND EXECUTED

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Activate AMR on BSC1. Set the AMR-specific control parameter AMR_CODEC_USED on (WOA). ZWOA:2,619,A; 2. Activate the AMR HR (EQY, W7M). a. Activate the AMR HR licence: ZW7M:FEA=1:ON:; For instructions on managing licences, see Licence-based Feature Management. b. Modify the AMR HR codec mode set: ZEQY:BTS=:HRC=; Value 0 means that the whole codec mode set is disabled.

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Modifying Speech CircuitsThe following procedure is executed once per TCSM2. There are two alternative ways to do the modification: speech circuits are removed and added during modification speech circuits are transferred automatically during modification The second way is simpler in the sense that it contains fewer MML commands than the first one. The modification is possible only between the types that use the same number of bits in the Ater interface, in other words the sub-multiplexing scheme is the same for the current and the new pool.

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Modifying Circuits with Circuit Removal and Addition1. Remove speech circuits of the first TC-PCM from the circuit group that contains circuits of pool 1 (CEC, RCR). a. ZCEC:ETPCM=,CRCT=1-1&&-31:BA; or: ZCEC:ETPCM=,CRCT=1-1&&-31:BL; b. ZCEC:ETPCM=,CRCT=1-1&&-31:NU; c. ZRCR:NCGR=: ETPCM=,CRCT=1-1&&-31; 2. Modify the TC-PCM type (WGM). ZWGM:,1:POOL=23; 3. Restart the TCSM unit (USU). ZUSU:TCSM,; The TCSM must be restarted because the TC-PCM type in the TCSM2 is changed and the TCSM unit is in WO-EX state. The Transcoder Configuration MML notifies about this during the execution of WGM command.30 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Modifying Circuits with Circuit Removal and Addition (2)4. Add speech circuits to the circuit group that contains circuits of pool 23 (RCA, CEC). a. ZRCA:NCGR=: ETPCM=,CRCT=1-1&&-31:CCSPCM=3; b. ZCEC:ETPCM=,CRCT=1-1&&-31:BA; c. ZCEC:ETPCM=,CRCT=1-1&&-31:WO;

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Modifying Circuits with Automatic Circuit Transfer1. Block speech circuits of the TC-PCM (CEC). ZCEC:ETPCM=,CRCT=1-1&&-31:BA; or: ZCEC:ETPCM=,CRCT=1-1&&-31:BL; 2. Modify the TC-PCM type (WGM). Note that the target circuit group has to exist. If the circuit group does not exist, create it with command RCC . ZWGM:,1:POOL=23:NCGR=; 3. Restart the TCSM unit (USU). ZUSU:TCSM,; The TCSM must be restarted because the TC-PCM type in the TCSM2 is changed and the TCSM unit is in WO-EX state. The Transcoder Configuration MML notifies about this during the WGM command. 4. Unblock speech circuit of the TC_PCM (CEC). ZCEC:ETPCM=,CRCT=1-1&&-31:WO;

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Create Speech Circuits on MSC This is will need to be created on the Nortel MSC.


d e v o m re

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Download Parameters on BSC When AMR is activated the default settings are active. It is advised to download after using MML/Plan Editor customised parameter settings for: Codecs used C/I thresholds Power and Handover thresholds

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Common Questions ImplementationQ: Do the TRX/BTS/BCFs need to be locked/unlocked to set AMR parameters A: No Q: Does GPRS have to be disabled/enabled? A: No Q: Quick non service affecting method to rollback? A: Rollback will be possible with just shutting down the MSC Circuit pool 23. BSC does not need to be restarted or AMR deactivated. Pool 23 is AMR only Transcoder pool.

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Unlock Speech Circuits on MSC AMR must be activated before MSC Speech circuits are unlocked as drops may occur. The MSC/NSS has no knowledge if the BSC has AMR activated or not.

The BSS engineers who activated the feature can monitor the usage of Transcoder usage codec during this testing, observing for holding time and traffic levels. MML command - ZRM:pcm number

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AMR Parameter Overview

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AMR BSC ParametersParameter TCH in handover Level BSC Name HRI Suggested Value 1 Comments With this parameter you define the traffic channel allocation during BSS internal or external handovers. The parameter controls the target cell selection and the TCH channel rate and speech codec determination in traffic channel allocation. The parameter can have the following values: 1= The call serving type of TCH has to be primarily allocated. The call serving type of speech codec inside the call serving type of TCH can change. 2 = The call serving type of TCH and the call serving type of speech codec are preferred to be primarily allocated during the speech connection. The channel rate change is possible during data connection, if necessary, and if the radio interface data rate allows it. 3 = The channel rate and speech codec changes are totally denied. 4 = The preferred channel rate of TCH and preferred speech codec have to be primarily allocated. 5 = TCH has to be primarily allocated from the best BTS of the handover candidate list. lower -> limit for FR TCH resources BSC BSC BSC BSC HRL HRU ACH IAC 20 40 1 1 btsLoadDepTCHRate (HRL) and btsLoadDepTCHRate (HRU) are considered in call set-up and handovers only when IAC=1. HR is to be assigned if free resources go below HRL. FR is to be assigned if free resources go above HRU. 1 = the currently used multirate configuration is preferred. 2 = the multirate configuration of target BTS is preferred. 1 = any rate, there are no extra requirements by the parameter and the chosen channel rate is defined by taking into account the currently used information for channel allocation. 2 = AMR FR is preferred over AMR HR and allocated despite of the values of the currently used information for channel allocation. IAC=2 overrides TCHRateInt (HRI) Enable slow link adaptation. This is a proprietary algorithm where codec mode changes happen every SACCH period (480ms) instead of as fast as 40ms. Y = downgrades and upgrades are applied N = downgrades and upgrades are not applied. If multirate configuration of source and target BTS are the same then ACH and ASG has no impact

In networks with mixed configuration of EFR and AMR, HRI = 4 is recommended: -> HRI Study

Threshold selection

upper -> limit for FR TCH resources

Threshold selection AMR configuration in handoversinitial AMR channel rate

slow AMR LA enabled

BSC

SAL

No

AMR set grades enabled38

BSC

ASG

No


AMR BTS Parameters (FR)Parameter AMR FR codec mode set Level BTS Name FRC Suggested Value 149 Comments With this parameter you define the codec mode set for a full rate channel. If the parameter is defined as disabled, then the whole codec mode set is disabled. Codec set used is 12.2(128), 7.40(16), 5.9(4), 4.75(1) kbit/s *) With this parameter, together with AMR FR threshold 1, you define the threshold for switching from codec mode 1 (lowest bit-rate) to codec mode 2 (second lowest bit-rate). Unused hysteresis is set as 0. With this parameter, together with AMR FR threshold 2, you define the threshold for switching from codec mode 2 (second lowest bit-rate) to codec mode 3 (third lowest bit-rate). Unused hysteresis is set as 0. With this parameter, together with AMR FR threshold 3, you define the threshold for switching from codec mode 3 (third lowest bit-rate) to codec mode 4 (highest bit-rate). Unused hysteresis is set as 0. With this parameter you define whether the initial codec mode used by the mobile station is defined explicitly in the AMR codec mode set or is it implicitly derived by the mobile station from the amount of codec modes in the AMR codec mode set. With this parameter you define explicitly the initial codec mode used by the mobile station. With this parameter you define the threshold for switching from codec mode 2 (second lowest bit-rate) to codec mode 1 (lowest bit-rate). Unused threshold is set as 0. With this parameter you define the threshold for switching from codec mode 3 (third lowest bit-rate) to codec mode 2 (second lowest bit-rate). Unused threshold is set as 0. With this parameter you define the threshold for switching from codec mode 4 (highest bit-rate) to codec mode 3 (third lowest bit-rate). Unused threshold is set as 0.

AMR FR hysteresis 1

BTS

FRH1

1(dB)

AMR FR hysteresis 2

BTS

FRH2

1(dB)

AMR FR hysteresis 3

BTS

FRH3

1(dB)

AMR FR initial codec mode indicator (ICMI)

BTS

FRI

0

AMR FR start mode AMR FR threshold 1

BTS BTS

FRS FRT1

0 9(dB)

AMR FR threshold 2

BTS

FRT2

12(dB)

AMR FR threshold 3

BTS

FRT3

16(dB)

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AMR BTS Parameters (FR), contdParameter Super reuse bad C/I threshold AMR FR Super reuse good C/I threshold AMR FR lower limit for FR TCH Resources Level BTS BTS BTS Name BCIF GCIF FRL Suggested Value 10 17 20 Comments With this parameter you define the downlink C/I ratio on a super-reuse TRX for triggering the HO from the super-reuse TRX. Defined for AMR FR calls. With this parameter you define the downlink C/I ratio on a super-reuse TRX for triggering the HO to the super-reuse TRX. Defined for AMR FR calls. With this parameter you define the percentage of full rate TCH resources that must be available for traffic channel allocation. Full rate TCHs are allocated until the number of free full rate resources is reduced below the threshold given in the parameter. The half rate resources are then allocated. With this parameter you define the percentage of full rate TCH resources that must be available for traffic channel allocation. Full rate TCHs are again allocated when the number of the free full rate resources increases above the threshold given by the parameter.

-> Threshold selectionupper limit for FR TCH Resources BTS FRU 40

-> Threshold selection

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AMR BTS Parameters (HR)Parameter AMR HR codec mode set Level BTS Name HRC Suggested Value 21 Comments With this parameter you define the codec mode set for a half rate channel. If the parameter is defined as disabled, then the whole codec mode set is disabled.Codec set used is 7.40(16), 5.9(4), 4.75(1) kbit/s. With this parameter you define together with the AMR HR threshold 1 the threshold for switching from codec mode 1 (lowest bit-rate) to codec mode 2 (second lowest bit-rate). Unused hysteresis is set as 0. With this parameter you define together with the AMR HR threshold 2 the threshold for switching from codec mode 2 (second lowest bit-rate) to codec mode 3 (third lowest bit-rate). Unused hysteresis is set as 0. With this parameter you define together with the AMR HR threshold 3 the threshold for switching from codec mode 3 (third lowest bit-rate) to codec mode 4 (highest bit-rate). Unused hysteresis is set as 0. With this parameter you define whether the initial codec mode used by the mobile station is defined explicitly in the AMR codec mode set or is it implicitly derived by the mobile station from the amount of codec modes in the AMR codec mode set.. With this parameter you explicitly define the initial codec mode used by the mobile station. With this parameter you define the threshold for switching from codec mode 2 (second lowest bit-rate) to codec mode 1 (lowest bit-rate). Unused threshold is set as 0. With this parameter you define the threshold for switching from codec mode 3 (third lowest bit-rate) to codec mode 2 (second lowest bit-rate). Unused threshold is set as 0. With this parameter you define the threshold for switching from codec mode 4 (highest bit-rate) to codec mode 3 (third lowest bit-rate). Unused threshold is set as 0. With this parameter you define the downlink C/I ratio on a super-reuse TRX for triggering the HO from the super-reuse TRX. Defined for AMR HR calls. With this parameter you define the downlink C/I ratio on a super-reuse TRX for triggering the HO to the super-reuse TRX. Defined for AMR HR calls

AMR HR hysteresis 1

BTS

HRH1

1(dB)

AMR HR hysteresis 2

BTS

HRH2

1(dB)

AMR HR hysteresis 3

BTS

HRH3

0(dB)

AMR HR initial codec mode indicator (ICMI)

BTS

HRI

0

AMR HR start mode AMR HR threshold 1

BTS BTS

HRS HRT1

0 14(dB)

AMR HR threshold 2

BTS

HRT2

17(dB)

AMR HR threshold 3

BTS

HRT3

0(dB)

Super reuse bad C/I threshold AMR HR Super reuse good C/I threshold AMR HR

BTS BTS

BCIH GCIH

10 17

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AMR HO & PC ParametersParameter Intra HO threshold Rx qual AMR FR Level BTS Name IHRF Suggested Value 4 Comments With this parameter you define the threshold level of the signal quality downlink and uplink measurements for triggering the intra-cell handover process for an AMR FR call in order to switch it to an AMR HR call (based on load). With this parameter you define the threshold level of the signal quality downlink and uplink measurements for triggering the intra-cell handover process for an AMR HR call in order to switch it to an AMR FR call. With this parameter you define the threshold level of the signal quality downlink measurements for triggering the handover. Defined for the default AMR HR set. With this parameter you define the threshold level of the signal quality uplink measurements for triggering the handover. Defined for the default AMR HR set. With this parameter you define the threshold level of the signal quality downlink measurements for triggering the handover. Defined for the default AMR FR set. With this parameter you define the threshold level of the signal quality uplink measurements for triggering the handover. Defined for the default AMR FR set. With this parameter you define the threshold level of the downlink signal quality measurements for the BTS power increase. Defined for the default FR AMR set. With this parameter you define the threshold level of the downlink signal quality measurements for the BTS power decrease. Defined for the default FR AMR set. With this parameter you define the threshold level of the uplink signal quality measurements for the MS power increase. Defined for the default FR AMR set. With this parameter you define the threshold level of the uplink signal quality measurements for the MS power decrease. Defined for the default FR AMR set. With this parameter you define the threshold level of the downlink signal quality measurements for the BTS power increase. Defined for the default HR AMR set. With this parameter you define the threshold level of the downlink signal quality measurements for the BTS power decrease. Defined for the default HR AMR set.

-> Threshold selectionIntra HO threshold Rx qual AMR HR

-> Threshold selection

BTS

IHRH

4

Threshold dl Rx qual AMR HR

BTS

QDRH

5

Threshold ul Rx qual AMR HR

BTS

QURH

5

Threshold dl Rx qual for AMR FR

BTS

QDRF

6

Threshold ul Rx qual AMR FR

BTS

QURF

6

PC lower threshold dl Rx qual AMR FR

BTS

LDRF

5

PC upper threshold dl Rx qual AMR FR

BTS

UDRF

3

PC lower threshold ul Rx qual AMR FR

BTS

LURF

5

PC upper threshold ul Rx qual AMR FR

BTS

UURF

3

PC lower threshold dl Rx qual AMR HR

BTS

LDRH

3

PC upper threshold dl Rx qual AMR HR

42AMR NOKIA AMR optimization / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL Specific HO andGuidelines PC Parameters

->

BTS

UDRH

1

AMR BTS Parameters (FR in RNW)

43


AMR BTS Parameters (HR in RNW)

44


AMR HO & PC Parameters (RNW)

45


AMR Parameter Setting for Channel & Codec Adaptation

46


Channel Adaptation - RTSL Parameters Following the BSC level AMR feature activation and the addition of circuit pool 23, AMR FR will be functioning on all sites with default parameters settings. To configure the RTSL for half rate support, the existing FR only configuration (TCHF) must be changed to Dual Rate (TCHD) depending upon the traffic need and blocking on the site. ZERM:BTS=x,TRX=x, CHx=TCHD; Configure AMR HR Packing triggers. The value depends upon how aggressive we want to deploy HR. The setting shall be in accordance with traffic/blocking and average C/I in the area. ZEEM:HRU=x,HRL=x; ZEQY:BTS=x,IHRF=x,IHRH=X;

47


Channel Adaptation - Packing & Unpacking Mechanism To trigger the packing of active Full Rate AMR calls to AMR Half Rate, traffic and quality threshold must be set. Spontaneous Packing of AMR FR to AMR HR calls is triggered: Free full rate resources reduces below the value of the parameter btsLoadDepTCHRate(HRL) At least 2 calls in which quality is above the amrHandoverFr(IHRF) and which uses the least robust codec mode Packing continues until the number of free full rate resources increases above the value of the parameter btsLoadDepTCHRate (HRU). Spontaneous unpacking of AMR HR calls to AMR FR calls is triggered when the quality of a AMR HR call degrades below the amrHandoverHr(IHRH). Cell load does not have an effect. HRL and HRU are set on BSC level but load evaluation is based on individual BTS. btsspLoadDepTCHRate (FRL) and (FRU) are BTS specific parameters. They have priority over btsLoadDepTCHRate (HRL) and (HRU) The feature is disable when set HRL > HRU or FRL > FRU Real network behavior shows that if FRL > FRU, but HRL < HRU, the AMR feature is enable

48


Channel Adaptation - Packing & Unpacking Mechanism Example: HRL = 40% HRU = 60% IHRF = 2 IHRH = 4 Packing starts when free FR resources below 40% and calls with RxQual below 2, and stops when free FR resources above 60% Unpacking when HR calls RxQual below 4

49


Codec Adaptation - Parameters The parameters "amrConfigurationFr: codecModeSet" & "amrConfigurationHr: codecModeSet" (FRC) determine the set of codecs in used.

Dynamic code adaptation is based on C/I estimation. Threshold and hysteresis: FRTx: AMR FR threshold x amrConfigurationFr: thresholdx, with x=1,2,3 FRHx: AMR FR hysteresis x amrConfigurationFr: hysteresisx, with x=1,2,3 HRTx: AMR HR threshold x amrConfigurationHr: thresholdx, with x=1,2,3 HRHx: AMR HR hysteresis x amrConfigurationHr: hysteresisx, with x=1,2,3 AMR optimization Guidelines / Jan 16 2006 / Ver 01.01 / NOKIA CONFIDENTIALth

50

NOKIA

TRX Prioritisation in TCH Allocation

51


Enhanced TRX Prioritization in TCH AllocationSDCCHpreferred TCHs for non-AMR calls

BCCH

Traffic channels in BCCH TRX can be in the first hand allocated for non-AMR terminals. Targeted for handling of non-AMR roamers and home PLMN non-AMR terminal subscribers. AMR terminals tolerate lower C/I radio conditions than the others Better signal quality can be provided for non-AMR terminals in BCCH TRX.

BCCH TRX TRX 2 TRX 3 TRX 4Fixed CS PS territory

Dynamic TCH Dynamic TCH

CS data calls are preferred over non-AMR terminals in BCCH TRX.

52


Enhanced TRX Priorisation in TCH Allocation New values of TRP:(TRX Priority in TCH allocation )TRP Effect

New values of BFG:(prefer BCCH frequency GPRS)BFG Effect

(default)

0

All TRXs are treated equally in TCH allocation

0

(default)

All TRXs are treated equally in TRX selection for GPRS use

1

A traffic channel is allocated primarily from the BCCH TRX

1

GPRS channels are allocated primarily from the BCCH TRX

2

A traffic channel is allocated primarily beyond BCCH TRX

2

GPRS channels are allocated primarily beyond the BCCH TRX

(new value)

3

A traffic channel is allocated primarily from the BCCH TRX for the non-AMR users and for the AMR users beyond the BCCH TRX

53


HO and PC in AMR

54


HO and PC in AMR Environment HOC and POC is done based on RX quality Following actions are taken based on Rx quality cases of PC & HO algorithms in BSC: If the quality is below lower thresholds then HO or PC (more power) is triggered depending on the current threshold values. Otherwise if quality is above lower thresholds, nothing is done. Respectively, if the quality is above upper thresholds then PC (less power) is triggered. Otherwise if quality is below upper thresholds, nothing is done. Above cases are valid only in quality HO, not for example in PBGT HO RXLEV and Power Budget HO parameters are identical for AMR and EFR AMR call would handover at the same point as an EFR call

55


Intracell HO in AMR New RxQual HO parameters are specified for FR and HR AMR and they are taken into account when making intra-cell handovers between FR AMR and HR AMR: Intra HO threshold Rx Qual for AMR FR Intra HO threshold Rx Qual for AMR HR Current Nx and Px values of RxQual thresholds are used. All the information (codec usage and quality) goes to BSC statistics part for further processing. Intra cell Handover process ( FR to HR packing ) is based upon BTS load, call quality and current codec being used as shown in the next slides.

56


Intracell HO in AMRIntra-cell HO process (packing) Packing Process

Previous Packing finished

No

No Packing attempt

YesTCH rate intra-cell Handover(TRIH) = 0?

No

TCH rate intra-cell Handover(TRIH) = 3?

Yes

YesTCH rate internal Handover(HRI) = 3

No Yesupper limit for FR TCH resources < lower limit for FR TCH resources Selection Based on Cell load

Yes

NoTRIH=0 Means: Constraints given by the BSS-level parameter TCH rate internal HO are followed TRIH=3 Means: Channel rate and speech codec changes denied HRI=3 Means: Channel rate and speech codec changes denied57 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

No

Intracell HO in AMRSelection Based on Cell load

Intra-cell HO process (packing)

Is packing being started?

Yes

Packing is stopped

Existing 2 calls with quality >intra HO threshold Rx Qual AMR FR ?

No Yes Yes

NoNo Packing attempt

No% of free TCH voice CHL < lower limit for FR TCH resources ? % of free TCH voice CHL > upper limit for FR TCH resources ?

Both calls using least robust codec mode?

No

Yes

No

YesPacking of 2 calls. Packing is considered as started HR Radio Resource Search

Packing is not started

58


Inter cell HO in AMR Separate RXQUAL threshold parameters for AMR on BTS level Default set to worse values compared to the EFR RXQual parameters (e.g. EFR =4, AMR = 5) Same px/nx values used for both AMR and EFR With these default settings AMR calls would be expected to have fewer HO due to quality

No difference in RXQUAL measurement method between EFR and AMR EFR call and AMR call in identical location should show identical RXQUAL measurements Packing/Unpacking Unpacking from HR to FR is always based on RX quality In congested cell with no available TS for unpacking, Inter-cell HO required based on RXQUAL. Improved robustness in AMR over EFR AMR better able to handle poor radio conditions - low RXLEV, poor RXQUAL, low C/I59 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

RXQuality Handover Parameters Separate thresholds for AMR-FR than for AMR-HR Different HO thresholds for AMR than for EFR Same px/nx values used for both AMR and EFRed v

m AMR allows to use more aggressive HO e thresholds (1-2 classes r lower) e BTS level parameters

o

is h T

e d i sl

b o t

60


Inter cell HO in AMRRXQUAL parameters for AMR HR and AMR FR Threshold dl Rx qual AMR HR threshold level of the signal quality downlink measurements for triggering the handover Threshold ul Rx qual AMR HR threshold level of the signal quality uplink measurements for triggering the handover Threshold dl Rx qual for AMR FR threshold level of the signal quality downlink measurements for triggering the handover Threshold ul Rx qual AMR FR threshold level of the signal quality uplink measurements for triggering the handover

61


AMR Configuration in Handovers amrConflnHandover 1 = the currently used multirate configuration is preferred 2 = the multirate configuration of target BTS is preferred amrSetGradesEnabl Y/N Y = downgrades and upgrades are applied N = downgrades and upgrades are not applied If multirate configuration of source and target BTS are the same, these 2 parameters has no impact.

62


AMR Configuration in Handovers If multirate configuration of source and target BTS are difference (e.g. Talk family BTS supports less codecs than UltraSite and MetroSite), the multirate configuration can be aligned before or after HO. Recommendation amrConflnHandover = 2 amrSetGradesEnabl = Y Mode modify is triggered for BTS and MS on source side before HO if target BTS support less codec (downgraded, UltraSite Talk family) Mode modify is triggered for BTS and MS on target side after HO if target BTS support more codec (upgrade, Talk family UltraSite) In order to make it possible to connect unidirectional speech path on target side, the multirate configuration on both sides should be the same (reduce muting period during HO).

63


AMR Thresholds OverviewRXQuality Class: 7 6 Qual_reason_HO for FR 5 4 unpack HR -> FR 3 Qual_reason_HO for HR; 2 pack FR -> HR 1 0 LDRH, LURH LDRF, LURF UDRH, UURH UDRF, UURF

64


Handover Prioritization When there are cells with In order to facilitate the continuation of an AMR call HO target cell list is sorted so that lightlyloaded AMR-capable cells are more attractive. AMR-capable cells can be defined by the AMR target cell of direct access to desired layer (DADLA) Prioritized by BTS Load Threshold (BLT) Prioritization only used for an on-going AMRmode call

Call set-up

AMR and without AMR

In AMR environment, DADL/B is used to handover AMR calls from non-AMR-capable cell to co-located AMR capable cells during call set-up phase. AMR cells which load below BTSLoadThreshold and meet hoMarginPBGT are prioritised for AMR call.

Handover

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

2) Prioritisation of AMR capable cells in handovers

No-AMR 2nd gen. BTS capable AMR capable UltraSite (co-located)65

SDCCH

TCH


Relation with other HOs: Priority1. 2. 3. 4. 5. Interference (UL or DL) NonBCCHLayerExit Uplink quality Downlink quality AMR unpacking due to UL level HO threshold and UL quality (unpacking is started instead of UL level based HO if both, UL level and UL quality for unpacking triggers) 6. Uplink level 7. AMR unpacking due to DL level HO threshold and DL quality (unpacking is started instead of DL level based HO if both, DL level and DL quality for unpacking triggers)8. 9. Downlink level MS-BS Distance

10. Turn-around-corner MS 11. Rapid field drop 12. Fast/Slow moving MS 13. Better cell (Power budget HO or Umbrella HO) 14. Load based HO in Common BCCH from BCCH/non-BCCH layer to non-BCCH layer 15. AMR packing 16. AMR unpacking

* Priority applies when criteria are fulfilled at the same time66 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Power Control in AMR There are special parameters for PC in AMR due to the better FER performance PC can be more aggressive than in EFR Parameters separately for FR and HR BTS level parameters

67


Power Control ParametersPC parameters for FR: PC lower threshold dl Rx qual AMR FR: threshold level of the downlink signal quality measurements for the BTS power increase PC upper threshold dl Rx qual AMR FR: threshold level of the downlink signal quality measurements for the BTS power decrease PC lower threshold ul Rx qual AMR FR: threshold level of the uplink signal quality measurements for the MS power increase PC upper threshold ul Rx qual AMR FR: threshold level of the uplink signal quality measurements for the MS power decrease

68


Power Control ParametersPC parameters for HR: PC lower threshold dl Rx qual AMR HR: threshold level of the downlink signal quality measurements for the BTS power increase PC upper threshold dl Rx qual AMR HR: threshold level of the downlink signal quality measurements for the BTS power decrease PC lower threshold ul Rx qual AMR HR: threshold level of the uplink signal quality measurements for the MS power increase PC upper threshold ul Rx qual AMR HR: threshold level of the uplink signal quality measurements for the MS power decrease

69


Handover & Power Control ParametersQuali ty 01

Intra HO Threshold Rx Qual AMR FR PcUpperThreshold UL/DL RXQual AMR FR/HR

Qual (load)/ Pack/ IntraHO

Decrease Power2

Level Ho

No PC Action Needed

PcLowerThreshold UL/DL RxQual AMR FR/HR

3

Increase Power Intra HO Threshold Rx Qual AMR HR4

Qual/ Lev Unpack/ IntraHO

Threshold UL/DL RxQual AMR FR/HR

5

Threshold UL/DL RxQual AMR FR/HR HoThreshold Lev UL/DL HoThreshold Interference UL/DL RxLevMinCell(n) RxLevAccMin Interference HO Quality Ho Level Ho No action needed PcUpperThreshold UL/DL RXQual FR/HR PcLowerThreshold UL/DL RXQual FR/HR PcUpperThreshold LevUL/DL PcLowerThreshold LevUL/DL RxLevAccMin RxLevMinCell(n) Power decrease Power increase No action needed70

Ho Thresholds7 -110 -108 -106 -104 -102

6

Quality HO

Interference HO

Actions

PcUpperThresholds LevUL/DL HoThreshold Interference UL/DL

Leve l

-84

-58

-54

-52

-98

-96

-94

-92

-90

-88

-86

-60

-56

-78

-100

-74

-82

-80

-76

-72

-70

-68

-66

-64

Pc Thresholds ActionsRxlevAccMin RxlevMin(n)

PcLower Thresholds Lev UL/DL HoThreshold Lev UL/DL


Switch to Slide Show mode

-62

-50

Impact at system level of Power Control ParametersP erformance vs. P C settings4.5%

EFR vs AMR

4.5% 4.0% % Bad Quality S amples 3.5% 3.0% 2.5% 2.0% 1.5% 1.0% 0.5% 0.0% P C=5/3 PC=5/4 PC=4/3 PC se ttin gs TC H FE R > 4% % ended c all avg estim ated M OS < 3.5

4.0%

100% AMRT CH fER > 4%

3.5%

e b o t e d i l s is h T3.0% 2.5% 2.0% 1.5% 1.0% 0.5% 0.0% 5%

d EFR PC=2/3 e 100% v o m re140 % 100% AMR PC=3/510% 15% 20% EFL( %) Codec MA EFR 25% 30% 35%

PC= 3/2

71


Radio Link Timeout in AMR

72


RLT Background 3GPP 05.08 states that Radio Link Failure (RLF) in the MS is determined by the success rate of decoding messages on the downlink SACCH The aim of determining RLF in the MS is to ensure that calls with unacceptable voice/data quality, which cannot be improved either by RF power control or handover, are either re-established or released in a defined manner The Radio Link Timeout (RLT) parameter controls that a forced release (drop) will not normally occur until the call has degraded to a quality below that at which the majority of subscribers would have manually released it The RLF procedure is implemented in the RRM at the BSC and is as follows: After the assignment of a dedicated channel a counter is initialized to RLT When a SACCH message is unsuccessfully decoded the counter is decreased by 1 When a SACCH message is successfully decoded the counter is increased by 2 If the counter reaches 0 a RLF is declared Call is released

73


RLT Background RLT is based on SACCH deletion. SACCH is though not using a dynamic codec like voice in AMR, which means: Using the EFR RLT value an AMR customer can have the call dropped because RLT = 0 when still the FER is good RLT is not anymore reliable with the same value in AMR than in EFR Due to the fact that the FER performance is different when comparing AMR calls to EFR calls, the Radio Link Timeout need to be defined separately for AMR The Radio Link Timeout parameter for AMR is ARLT, available from S11.5. The principle of ARLT is the same than in the RLT but it is used only for the AMR capable mobile stations. With ARLT the maximum value of the radio link counter expressed in SACCH blocks for AMR calls is defined. The values range from 4 to 64 blocks, and can be changed by 4-block steps at a time. The default value for ARLT is 20 (SACCH).

74


RLT AMR-FR vs. EFR - Test 1 The RLT is based on SACCH erased frames, which are independent of speech frames The tests were aimed to find RLT value producing the same speech degradation in AMR as EFR would suffer with default RLT value for this traffic (i.e. 20)EFR Number of Number of unaccepta unacceptable ble samples sa mples (FER>50%) ( FER>25 %) 13 42 54 25 50 42 54 38 50 54 46 58 58 46 67 75 58 67 58 75 54 58 79 58 88 92 63 88 83 88 88 88 75 75 83 83 96 92 83

AMR Number of unacceptable samples (FER>50%) 0 0 1 1 1 1 1 2 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Number of unaccepta ble samples (FER>25 %) 1 2 3 4 5 6 7 8 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Time

RLT

FER

Time

RLT

FER

RLT to select

e b o t e d i l s isBQSThe indicator used was number of h T the FER (with FER>50%/25%) betweentime when the counter starts decreasing from its top value (64) to the point where the link would be released (i.e., when the counter is decreased by the RLT parameter)

00:25:55:82 00:25:56:30 00:25:56:78 00:25:57:26 00:25:57:74 00:25:58:23 00:25:58:71 00:25:59:20 00:25:59:68 00:26:00:16 00:26:00:64 00:26:01:12 00:26:01:60 00:26:02:08 00:26:02:56 00:26:03:05 00:26:03:53 00:26:04:01 00:26:04:49 00:26:04:97 00:26:05:45 00:26:05:93 00:26:06:41 00:26:06:89 00:26:07:37 00:26:07:85 00:26:08:34 00:26:08:82 00:26:09:30 rivad a: 00:26:09:78 RLT = 44 is equivalent to 0 when using FIXED RLT 00:26:10:26 equal to 20 (DEFAULT 00:26:10:74 NOKIA VALUE) 00:26:11:23 00:26:11:71 00:26:12:19 00:26:12:67 00:26:13:15 00:26:13:63 00:26:14:11

64 64 63 62 64 63 62 64 64 63 62 64 64 63 62 61 60 59 61 60 59 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44

d e v o m re

00:26:01:79 00:26:02:27 00:26:02:76 00:26:03:24 00:26:03:72 00:26:04:20 00:26:04:68 00:26:05:16 00:26:05:65 00:26:06:13 00:26:06:61 00:26:07:09 00:26:07:58 00:26:08:06 00:26:08:54 00:26:09:02 00:26:09:50 00:26:09:99 00:26:10:47 00:26:10:95 00:26:11:43 00:26:11:91 00:26:12:40 00:26:12:88 00:26:13:36 00:26:13:84 00:26:14:32 00:26:14:80 00:26:15:28 00:26:15:76 00:26:16:25 00:26:16:73 00:26:17:21

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 39 38 37 36 35

29 43 75 50 29 50 29 70 21 63 63 82 92 78 58 71 92 91 67 88 88 83 100 63 70 96 88 80 88 82 95 78 92

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 25 26 27 28 29

26

27

RLT has very high impact on DCR75 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

RLT AMR-FR vs. EFR - Test 2 Aim is to evaluate when AMR-FR is used which RLT value will result in comparable performance (point at which call is released) to the recommended RLT for EFR

d of speech The RLT is based on SACCH erased frames, which are independent e v the same speech o frames. The principle of the tests is to find RLT value producing m during 30 sec before degradation (FER > 15 % MOS < 1.5 no audible speech e r dropping) in AMR as EFR would suffer with default e RLT value for this traffic (i.e. 20) d i The driving route started at a good coverage location and ended at a bad coverage l s area is Th e b o t

76


AMR vs. EFR: FER Before DroppingRLT 20100 90 80 70 50 40 30 20 10 0 30 to 25 25 to 20 20 to 15 15 to 10 10 to 5 5 to 0 seconds before dropping EFR AMR FER (%) FER (%) 60 100 90 80 70 60 50 40 30 20 10 0

RLT 28

30 to 25

RLT 32100 90 80 70 FER (%) 60 50 40 30 20 10 0 30 to 25 25 to 20 20 to 15 15 to 10

FER (%)

o t e d i l s is h T10 to 5 5 to 0

be100 90 80 70 60 50 40 30 20 10 0

d e v o m re25 to 20 20 to 15

15 to 10

10 to 5

5 to 0

seconds before dropping EFR AMR

RLT 36

30 to 25

25 to 20

20 to 15

15 to 10

10 to 5

5 to 0



FER average every 5 seconds, during last 30 seconds before dropping for: RLT = 20, 28, 32, 3677 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Dropped Call Experience Dropped call experience: how long terminal does not receive any audible speech (MOS 15 % during last 30 seconds before dropping, for RLT dAMR, FER > 15 % RLT = 20 RLT = 28 RLT = 32 RLT = 36 RLT = xx 10-15 seconds before dropping

l s is h 18-22 seconds before dropping T15-20 seconds before dropping 25-30 seconds before dropping

t e id

e v o m EFR, FER > 15% e r e b 25-30 s. before drop o

Conclusion:

35-40 s. before drop

AMRRLT=36 has a similar dropped call experience to EFRRLT=20

78


EFR customers w/ increased RLT due to AMR EFR customers wont be negatively effected from increased RLT The only effect that is visible is a possible decrease in the (Dropped Call Ratio) DCR due to the fact that, possibly, due to the longer RLT some customer will close the d e conversation will the system will release it. Note that thesev cases should be pretty o rare due to the fact that the cases where the UL link ism still available (RLT > 0) and the DL link is not available (RLT = 0) are rare. re


79


MaxCap Feature

80


General Description MaxCap feature was developed to improve the AMR channel adaptation performance It was observed that when inter cell handover and unpacking is triggered, and there is no suitable target cell, the call remains in HR the call does not unpack As a result Voice Quality of HR call may become worse and customer will experience bad speech quality The MaxCap feature can be activated/deactivated from S11.0 CD 3.0 onwards and the default value is ON (unpacking allowed) Note that when MaxCap feature is ON unpacking is allowed in the specific condition described above. Therefore, we expect more number of intra cell HOs (depending upon quality threshold, Nx/Px) and this increases the probability of dropping calls

81


MaxCap OFF If quality HO is triggered without a suitable target cell, the call will stay in HR and will not unpack Case 1: HoThresholdsQualUL (quality HO) = amrHandoverHR (unpacking) -> call will not unpack if there is no suitable neighbor

Case 2: If HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) a) the call will unpack only if the RXQUALITY does not go higher than the value set for unpacking. b) if the RXQUALITY triggers unpacking and quality HO at the same time, the call will not unpack

82


MaxCap OFF /Case 1 HoThresholdsQualUL (quality HO) = amrHandoverHR (unpacking) -> call will not unpack if there is no suitable neighbor

When the RXQUALITY reaches the set QHO threshold and there is no target cell the call remains in HR.83 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

If there is a suitable target cell the call hands off and the rate is based on IAC and load.

MaxCap OFF /Case 2a HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) -> the call will unpack in case the RXQUALITY does not go higher than the value set for unpacking

84

RXQUALITY reaches the unpacking threshold first and triggers unpacking. The call goes from HR to FR. Later, RXQUALITY reaches QHO threshold and QHO is NOKIA AMR optimization Guidelines / Jan 16 2006 / Ver 01.01 / NOKIA CONFIDENTIAL initiated.th

If there is a suitable target cell the call hands off and the rate is based on IAC and load. Otherwise it remains in the old cell.

MaxCap OFF /Case 2b HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) -> if the RXQUAL triggers unpacking and quality HO at the same time, the call will not unpack

85


The RXQUALITY jumps up quickly triggering both QHO and unpacking at the same time. If there is no target cell the call remains in HR.


MaxCap ON If quality HO is triggered and there are no suitable target cells, the call will unpack. Case 1: HoThresholdsQualUL (quality HO) = amrHandoverHR (unpacking) Case 2: HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) a) b) the RXQUALITY does not go higher than the value set for unpacking the RXQUALITY triggers unpacking and quality HO at the same time

->

In Case1 and Case2 the call will always unpack if there is no suitable neighbor

86


MaxCap ON /Case1 HoThresholdsQualUL (quality HO) = amrHandoverHR (unpacking) -> call will unpack if there is no suitable neighbor

When RXQUALITY reaches the set QHO threshold and there is no target cell the call will unpack to FR.87 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL


MaxCap ON /Case 2a HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) -> RXQUALITY weakens slowly -> the call will unpack

88

RXQUALITY reaches the unpacking threshold first and triggers unpacking. The call goes from HR to FR. Later, RXQUALITY reaches QHO threshold and QHO is NOKIA AMR optimization Guidelines / Jan 16 2006 / Ver 01.01 / NOKIA CONFIDENTIAL initiated.th

If there is a suitable target cell the call hands off and the rate is based on IAC and load. Otherwise it remains in the old cell.

MaxCap ON /Case 2b HoThresholdsQualUL (quality HO) > amrHandoverHR (unpacking) -> RXQUALITY weakens rapidly -> the call will unpack

89


The RXQUALITY jumps up quickly triggering both QHO and unpacking at the same time. If there is no target cell the call will unpack to FR.


AMR Optimisation Remarks

90


AMR Optimisation Remarks (1/2) It should be noted that the impact to BSC capacity for each dual rate timeslot is double the impact of a full-rate-only RTSL. This impact is seen in the maximum number of RTSLs that may be attached to a BCSU (max. 512 = 64 FR TRXs per BCSU). For this reason, only a limited number of radio timeslots should be configured as Dual Rate. While only dual rate timeslots may serve HR mobiles, they are the last timeslots to be allocated FR traffic. This avoids filling up the valuable DR slots with FR only traffic. This priority of allocating FR only timeslots overrides the TRP preference defined for the cell. (i.e. if TRP prefers BCCH but all BCCH timeslots are DR while Hopping timeslots are FR, FR calls will be assigned to hopping layer first), HR time slots are allocated based on load thresholds. With the AMR HR implementation BSCs maximum channel capacity 4096 must be taken into the account in BSCs TRX amount dimensioning. For example, the BSC2i provides with 512 full-rate TRXs capacity or 256 half rate TRXs. Unpacking shall take place before any HO is triggered to other cells.91 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

AMR Optimisation Remarks (2/2) Aggressive PC settings shall be used for higher capacity gain where as for better speech quality conservative PC setting shall be used. HR shall be used aggressively in dense urban areas where C/I is good and traffic is very high whereas in rural area FR shall be preferred and HR shall be used conservatively based on traffic loads Couple of trials were performed to better understand the affect of parameter changing on performance and find best set of parameters for optimum performance in AMR network. Drive tests were done to understand AMR algorithms and check the working in real network

92


FRTx / HRTx Optimisation Trial

93


Trial on FRTx/HRTx 9 sites were selected RVSDBSC16 to see the affect of changes in the FRT/HRT/FRH/HRH values. Three set of parameters were tested as given in the following table. Parameter changes were made only for few hours for drive test purpose.Parameter AMR Configuration FR Hysteresis 1 (dB) AMR Configuration FR Hysteresis 2 (dB) AMR Configuration FR Hysteresis 3 (dB) AMR Configuration FR Threshold 1 (dB) AMR Configuration FR Threshold 2 (dB) AMR Configuration FR Threshold 3 (dB) AMR Configuration HR Hysteresis 1 (dB) AMR Configuration HR Hysteresis 2 (dB) AMR Configuration HR Hysteresis 3 (dB) AMR Configuration HR Threshold 1 (dB) AMR Configuration HR Threshold 2 (dB) AMR Configuration HR Threshold 3 (dB) Current Value 1 1 1 9 12 16 1 1 0 14 17 0 Case 1 1 1 1 11 14 18 1 1 0 16 19 0 Case 2 1 1 1 7 10 14 1 1 0 12 15 0 Case 3 2 2 2 9 12 16 2 2 0 14 17 0

94


Trial Area 1na F wy

Sa nta A

ra Mi d Blv da

C071I5

3007

Studebaker Rd

E940 C495State Hwy 91

Artesia

Fwy

RVSDBSC16A rt esiValley View St

Malv er

nA

ve

Artesia Blvd

I 605

Pioneer Blvd

C679

aA ve

C727Ma nc he st er B

C780

C400

lvd

E008

South St

Orang

C183

0130Del Amo Blvd

vd

La Palma AveBloomfield Ave

3107

State Hwy 39lvd ch B Bea

Carmenita Ave

Knott StKnott Ave

N Pioneer Blvd

Norwalk Blvd

C313

nG Sa rie ab

onal

r ive lR

Diag

Carson St

N Lo s Co yotes

Carson Ave

C086

Lincoln Ave

W Lincoln Ave

y Fw

C527

95


Moody S

Trial Area 2Sa nAlo ndr a

ta

An

a

Fw

Studebaker Rd

Valley View Ave

Bl v

y

d

e Alondra Av

I5

E940 C495

Artes ia Fw y

5 I 60

C679

Valley View St

C780 C400 E008

Sou th S t

Carmenita Ave

C472

0130Amo BlvdBloomfield Ave

vd

La Palma AveN Pioneer Blvd Pioneer Blvd

3107

Moody St

0137 0137

Norwalk Blvd

96

NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIALSa n ab G r

DL Codec Usage100 90 80 70 60 50 40 30 20 10 0 Current Value Case 1 Case 2 Case 3Cu rre nt t va hres lu e h o ld Lo we Mo r th re res co spee hold d in c h g

12.2 kbit/s 7.4 kbit/s

Hi gh Mo er t re hre s c co han hold d in n e l g

Hy ste 4.75 r e kbit/s fro sis m 1 t cha o 2 ng db ed

5.9 kbit/s

97


UL Codec Usage100 90 80 70 60 50 40 30 20 10 0 Current Value Case 1 Case 2 Case 3

No noticeable change in codec set usage12.2 kbit/s 7.4 kbit/s 5.9 kbit/s 4.75 kbit/s

98


FER Comparison Area 1

Case 1

Case 2

Case 3

Current Value

99


FER Comparison Area 2

Case 1

Case 2

Case 3

Current Value

100


Trial Summary There is no noticeable change in DL FER with change in FRTx/FRHx values. There is a change in codec usage in DL with change in the thresholds. No noticeable change in codec usage in UL. The overall C/I is good in the area chosen for the trial and mostly codec 12.2 and 7.4 are used. The current threshold values are good as best codec in terms of speech is used most of the times. Another area ( Trial area 1 ) is selected where the C/I is not as good so that we can see the affect of FRTx/HRTx values on the DL FER. The DL FER is best when using the current set of FRTx/HRTx values and degraded in all other three set of values. The current set of FRTx/HRTx values shall be used to have best DL FER.101 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

HOC, POC, BTS Optimisation Trial

102


Trial Objective, Schedule, Parameter Setting, Area Objective : Identify the best set of HOC, POC, BTS for an AMR network. Schedule : Phase I Phase II Phase III Before 01/22/04 01/22/04 02/02/04 = Parameter Setting 1 = Parameter Setting 2 = Parameter Setting 3

Area LSANBSC09 was selected as test area for the trial.

103


Parameter AMR Configuration FR Hysteresis 1 AMR Configuration FR Hysteresis 2 AMR Configuration FR Hysteresis 3 AMR Configuration FR Threshold 1 AMR Configuration FR Threshold 2 AMR Configuration FR Threshold 3 AMR Configuration HR Hysteresis 1 AMR Configuration HR Hysteresis 2 AMR Configuration HR Hysteresis 3 AMR Configuration HR Threshold 1 AMR Configuration HR Threshold 2 AMR Configuration HR Threshold 3 AMR HO HR Threshold DL RxQual AMR HO HR Threshold UL RxQual AMR POC FR PCL Threshold DL RxQual AMR POC FR PCL Threshold UL RxQual AMR POC FR PCU Threshold DL RxQual AMR POC FR PCU Threshold UL RxQual AMR POC HR PCL Threshold DL RxQual AMR POC HR PCL Threshold UL RxQual AMR POC HR PCU Threshold DL RxQual AMR POC HR PCU Threshold UL RxQual PC Interval PC L T Qual DL RxQual PC L U Qual DL RxQual HO T Qual DL Rx Qual HO T Qual UL Rx Qual104

Parameter SettingLevel BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS BTS Poc POC POC HOC HOC Setting 1 1 1 1 12 18 22 1 1 2 22 28 0 6 6 5 5 1 1 4 4 1 1 0 5 5 5 5 Setting 2 2 2 2 18 24 32 2 2 0 28 34 0 5 5 4 4 3 3 2 2 0 0 1 3 3 4 4

Setting 3 2 2 2 18 24 32 2 2 0 28 34 0 5 5 4 4 3 3 2 2 0 0 0 5 5 5 5

Comments Setting 1 and 3 are very aggressive (low POC & HOC quality threshold) as AMR allow MS to maintain good FER in low C/I


CODEC Profile Composition of Calls 70% calls using AMR Codec 30 % calls using EFR Codec This profile didnt change in the different trial phases.

105


UL FER Behaviour Observation Overall UL FER profile (FER AMR maintains good speech quality in the situation where the connection faces low C/I or low signal level. Also due to retransmissions schemes used by these channels the probability of signaling success maintain very high even for very degraded conditions Capacity -> HR utilization doubles the hardware capacity of the cell since two half-rate connections can be allocated to fill only one timeslot. Practically the gain is up to 150% higher capacity for the same quality Coverage -> additional 3-4 dB effective coverage Cost (HR hardware efficiency) -> 20-40% lower number of TRXs Improved BCCH plan: tighter frequency reuse or better quality with same frequency reuse, potentially releasing frequencies to be used on the non-BCCH layer

124


AMR KPIs and Network Doctor Reports

125


AMR Performance Monitoring AMR brings new speech codecs and channel encoders into air interface Speech Codecs impact would be reflected in the speech quality perceived Channel encoding enhancement is translated into better error correction capabilities (lower FER for same RawBER), which, in turn, enhances the speech quality Traditional performance monitoring indicators based on RXQUAL distribution, or Drop Call Rate, etc. does not reflect clearly the perceived speech quality by the end user. New methods to monitor the performance of AMR closer to speech quality perceived by the user. 2 Main indicators are proposed: FER and O-MOS (Objective MOS). O-MOS is not simple to measure (BSS 10.5) FER is available in UL, but DL FER will be reported when R99 MS come. In the meantime DL FER is just estimated from RXQUAL values

RXQUAL

FER

O-MOS

126


AMR KPIs RXQUALITY: Reported raw bit error rate RXLEV: Reported received power FER: Frame Erasure Rate (after decoding) Codec distribution MOS - speech quality FER per codec Call Drop Rate and other standard benchmarking measures Network collected measurements:Microsoft Word Document

127


AMR KPIs The AMR feature itself will not impact the individual connections DCR, but it will affect the overall system DCR since the interference generated in the network is lower due to the AMR power control settings. Radio Link Timeout can be adapted to AMR in order for dropped calls to maintain the same correlation with voice quality degradation as withd EFR

The new standard was implemented to Los Angeles market .Increasing the radio link timeout to 44 clearly improved the retainability in L.A. core area. Quality -> better perceived speech quality. Traditionally, GSM voice quality has been usually benchmarked based on BER measurements With Frequency Hopping and AMR, BER becomes increasingly meaningless and therefore alternative indicators are needed to benchmark the voice quality BSS10.5 brings FER based counters: In UL, the system measures the UL FER and related counters are available In DL, the system estimates the DL Frame Erasure Probability (FEP) based on the rest of information available

e v o m AWS National standard changed for Radio Link r Timeout changed from 20 to 44 e e b SACCHs.The new standard is due to the ofact that the AMR calls may still have a t s t good communication but radio link timeout is small and call is cleared based on lle u b e RLT. Thes

128


MOS & FERExample of relation MOS-FER: 4-5% FER seems to be acceptable for almost all codecs M OS0 .5 0 P e r c e iv e d q u a lit y ( M O S ) d e g r a d a t io n a s a f u n c t io n o f t h e F E R ( FR T e s t s in C le a n S p e e c h )

M OS0 .5 0

P e r c e iv e d q u a lit y ( M O S ) d e g r a d a t io n a s a f u n c t io n o f t h e F E R ( H R T e s t s in C le a n S p e e c h )

0 .0 0

- 0 .5 0

GSM 06.7 5

0 .0 0

- 0 .5 0

- 1 .0 0

- 1 .0 0 7 .9 5 H R

- 1 .5 0

- 2 .0 0

- 2 .5 0

1 2 .2 1 0 .2 7 .9 5 F R 7 .4 F R 6 .7 F R 5 .9 F R 5 .1 5 F R 4 .7 5 F R

- 1 .5 0

7 .4 H R 6 .7 H R

- 2 .0 0

5 .9 H R 5 .1 5 H R

- 2 .5 0F ER

4 .7 5 H R F ER

- 3 .0 0 0 .0 0 1 % 0 .0 1 0 % 0 .1 0 0 % 1 .0 0 0 % 1 0 .0 0 0 % 1 0 0 .0 0 0 %

- 3 .0 0 0 .0 0 1 % 0 .0 1 0 % 0 .1 0 0 % 1 .0 0 0 % 1 0 .0 0 0 % 1 0 0 .0 0 0 %

MOS degradation for FR

MOS degradation for HR

129


RXLEV and Power Budget HO parameters identical for AMR and EFR AMR call would handover at the same point as an EFR call.

AMR Effect on HO_QUALITY

Separate RXQUAL threshold settings for AMR Default set to worse values than EFR. (e.g. EFR =4, AMR = 5) With these default settings AMR calls would be expected to have fewer HO due to quality No difference in RXQUAL measurement method between EFR and AMR EFR call and AMR call in identical location should show identical RXQUAL measurements Packing/Unpacking Unpacking from HR to FR is always based on RX quality In congested cell with no available TS for unpacking, Inter-cell HO required based on RXQUAL.

130


AMR Effect on HO_Failures Improved robustness in AMR over EFR AMR better able to handle poor radio conditions - low RXLEV, poor RXQUAL, low C/I Separate RXQUAL HO threshold for AMR Effort to squeeze more performance from AMR could have negative impact in case parameters are not properly set up and/or traffic is low Packing/Unpacking Congestion could cause negative impact to HO_Fail No available TS for unpacking within cell. Inter-cell HO required Conclusion Optimization of separate AMR parameters is important to ensure no negative impact to HO_Failures. Different environments will need different parameter settings to optimise the performance. Unpacking algorithm under congested conditions may negatively impact HO_Failures

131


AMR Effect on DCR The AMR feature itself will not impact the individual connections DCR, but it will affect the overall system DCR since the interference generated in the network is lower due to the AMR power control settings. Radio Link Timeout can be adapted to AMR in order for dropped calls to maintain the same correlation with voice quality degradation as with EFR (RLT value could be moved from 20 to 36, for instance)

132


AMR Effect on BH_Congestion Use of AMR HR will decrease BH_Cong Special dimensioning techniques are required: % of HR capable terminals -> system level Load in busy hour (C/I distribution) determines % of HR terminals which can use HR -> cluster level HR Dimensioning tables determine the traffic (Erlangs) to be carried for a certain TSL configuration, a certain grade of service and % of HR traffic -> cell level

133


Network Doctor Reports related to AMR Report 246: Summary report for AMR KPI Percentage of call time using non-AMR, AMR-FR and AMR-HR UL/DL RxQual classes for non-AMR, AMR-FR and AMR-HR UL/DL FER classes for non-AMR, AMR-FR and AMR-HR Report 244: Distribution of call samples UL/DL by codecs and RxQual classes In FLA the codec mode reported is the last used in 480ms measurement interval (statistics will be fully accurate for SLA) Report 245: Distribution of call samples UL/DL by FER classes separated for codec types and rates

Report 247: Call Failure rate per codec type Report 248: Seizure and failure statistics for codec set modifications in internal HO Report 249: AMR counters summary

134


AMR MML Commands

135


MML Commands Following are the frequently used MML commands used for AMR activation, measurement, parameter monitoring and changes ZWOC:2,619:A; , Activate AMR at BSC ZWOC:2,628,A; Activate FER Feature at BSC ZWOS:2; Output Feature Activation Status ZTPM:MEASUR,FER:ALL,00-00-2400,15:CL1=2,CL2=5,CL3=10,CL4=20,CL5=40,CL6=70,CL7=120,WIN=2,:; Activate FER Measurement ZEQO:BTS=X:AMR; Output BTS level AMR parameters ZEEO:GEN; Output BSC Level AMR parameters ZEUO:BTS=X; Output AMR Power control parameters ZEHO:BTS=X; Output AMR Hand-off and packing parameters ZEGO:PAR; Output FEP parameters

136


AMR & Soft Channel Capacity Feature (S11.0)

137


Soft Channel Capacity to Help AMR Deployment One of the NOKIA BSS practical limits that has been highlighted from the customer is the fact that we cant deploy all the BSC as HR This is true till S10.5 In S11.0 Nokia is introducing the Soft Channel Capacity feature that allows to define all the RTSL in the BSS as Dual Rate This will have in important (positive) impact on the OPEX and CAPEX savings for the customers. As we write the feature is under trial in the AWS Los Angeles market but it is very promising UPDATE!!!!

138


BSC Capacity RoadmapBSC2iBSC Release Platform Capacity PCUs Erlang Connectivity TRX TCH E1/T1 BTS Site BTS sector 512 4 096 144 248 248 768 Ch 512 144 248 248 512 144 248 512 660 124 248 248 960 Ch 768 Ch 660 124 248 248 660 256 500 660 2 000 32 000 256 / rack + SDH/SONET 2 000 2 000 10 000 8 192 8 192 5 280 10,560 10 560

BSC3i

S10.5 S11.0 S11.5 S10.5 S11.0 S11.5 B9 B9 B11 B11 B11 B9 16 3 040 16 16 24 3 920 24 24

Black = Under Development Blue = Planned S12 (Planning Items) B12 BSC3i 2-rack 96 11 880

3 040 3 040

3 920 3 920

TCSM/MGW Ch 960 Ch

139


Attachments- HRI Study - Packing/unpacking Threshold

140


OXNARD BSC 2 PERFORMANCE DEGRADATIONToni Viitanen and Timothy Paul 05/12/03

141


Back to AMR Parameters

Executive SummaryOn April 16 AMR was activated on BSC 16. Upon activation the following issues were seen: 1. Retain ability degradation TCH Drops increased from close 2000 to 3300/day.

Root cause found. TCH HO Drop increased from 1000 to 1500/day.

Root cause found.1. SDCCH Accessibility degradation

This is due to pool switching, will be confirmed after testing with new pool settings.1. Ericsson TEMS phone DTMF tones sustained Root cause investigation ongoing

142


Major Events Event 1 Event 2

AMR activated on 5/16/03 May 5, 4:00 PM - AMR pool blocked accidentally.

Event 3

May 7, 1:00 PM AMR pool reactivated, Pool size doubles. Event 4

May 8, 10:00 AM Downlink DTX turned OFF

143


Ericsson TEMS phone DTMF tones sustained DTMF signalling is between MS and MSC and is transparent to BSS Abis traces indicate that MS did not send the STOP DTMF message to MSC => Hence STOP DTMF ACK message was not sent by MSC.

UL event CHAN. ACT. ACK (DCh) T=0 EST. IND (RLL) T=0 ASSIGNMENT COMPLETE (RR)

DL event Chan. Act. (AMR)

ALERTING CONNECT CONNECT ACKNOWLEDGE (CC) (SSN: 0) START DTMF (CC) (SSN: 1) START DTMF ACK STOP DTMF START DTMF T200 (CC) (SSN: 0) STOP DTMF ACK (CC) (SSN: 1) START DTMF ACK

(CC) (SSN: 0) (CC) (SSN: 0)

(CC) (SSN: 0) (CC) (SSN: 0) (CC) (SSN: 0)

CHANNEL RELEASE (RR) DEACT. SACCH (DCh) T=0 RF CHANNEL REL. (DCh) T=0 RF CH. REL. ACK (DCh) T=0144 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

Nokias implementation of 26.093 CR BTS SW CX3.3 Following changes are implemented for BB2E: If a FACCH needs to be sent during a speech pause, and: 1) if the frame preceding the FACCH is not of TX_TYPE=SPEECH_GOOD, then an ONSET frame shall be signaled to the CHE, followed by the FACCH frame(s); 2) if the frame following the FACCH frame is not of TX_TYPE=SPEECH_GOOD, then a SID_FIRST shall be signaled to the CHE.

BTS SW CX3.3-1

Changes mentioned above are implemented for BB2A Following changes are implemented for both BB2E and BB2A3) A stolen SID_UPDATE should be rescheduled on the frame subsequent to the SID_FIRST marker that follows the FACCH frame(s) (when that marker exists), unless that rescheduling would steal a frame of TX_TYPE="SPEECH_GOOD", or if a frame of TX_TYPE="SID_UPDATE" has been received before the rescheduling could take place. This rescheduling shall not affect the timing of subsequent SID_UPDATE frames.

145


Analysis of DL DTX Dropping calls can be seen when making calls with some phones through Nokias infra. Other related problems that may occur are DTMF, Hold-mode and even some audible noises. Problems occur only when AMR DTX is on. Change Request to GSM 26.093 Handling of FACCH and RATSCCH during AMR DTX It helps phones to detect FACCH messages during AMR DTX. Without implementing this it may cause call dropping and disturbing noises with some terminals. Note, this CR is targeted to 3GPP release 6. Nokia has implemented the following of CR: Specify that FACCH frames shall be framed by ONSET and SID_FIRST in order to fill that part of the burst which would otherwise be undefined BTS SW that includes these changes is CX3.3 Recommendation: Until deployment of CX3.3, it is recommended to turn OFF DL DTX.

146


TCH Drops and TCH HO summary

TCH Radio Drop (counter 1003) and TCH HO Drop Call dropping could be explained if pool switchingwas absolutely necessary but there are no appropriate circuits available (all pools full, congestion) and HO is not possible then the call is dropped if radio conditions go worse enough This situation could not be seen in monitoring logs but switching of pools were always successful and thus it cannot be proven that problem is due to lack of Ainterface circuits

New Nethawk logs were captured on 05/07 Most of error indication message (CC 20) comes after call release procedure was triggered This will trigger the counter 1003 in conversation phase and not in Call release phase as BSC does not know of the call release procedure yet. Disconnect and Release messages are transparent to BSC T200 timer expires when call release phase is triggered Further investigation is ongoing from BSC and BTS perspective

147


SDCCH_ACC degradation analysis Analysis shows the counter increases due to congestion and pegs counters (1122, 4097, 4098, 4101), call is redirected due to AMR circuit not available. Call continues as EFR to EFR. Increase in counters is caused due to the incorrect dimensioning of the AMR circuit pools (20 % penetration of AMR mobiles in the Oxnard area, dimensioning done for lower penetration). If AMR pool full->pool switching to EFR pool. Additional T1 circuits to be added week 19. No new information until new circuit available. This is NORMAL Behaviour Scorecard analysis on SDCCH_ACC formula will be done after additional circuits are available to ensure appropriate grading.

148


SDCCH_ACC counter increase detailed analysis 1(3)Message monitoring for AIV, RRM, and HAS were analysed and below are the findings: A handover channel required message is sent by the A-interface program block to the handover program block with the following parameters: Channel rate and type = fr_p_ch_al_c (Full or half rate TCH, full rate preferred, changes allowed also after first channel allocation as a result of the request) A_Circuit type = 0x17 = fr3_hr3_c (Pool 23, supports full rate speech version 3 and half rate speech version 3) Pool_switch_ind (indicates the pools to which the current pool is allowed to be changed) = 0x0003 = fr1 and fr2 Handover program block passes on this request to the Radio Resource Manager program block with the same parameters to reserve a channel149 NOKIA AMR optimization Guidelines / Jan 16th 2006 / Ver 01.01 / NOKIA CONFIDENTIAL

SDCCH_ACC counter increase detailed analysis 2(3) Radio Resource Manager responds to the channel request with a negative acknowledgement with the following fields: Dx_cause = rrm_switch_crc_pool_c Cause = switch_crc_pool_c Handover program block then sends a handover failure message to the A-interface program block with cause rrm_switch_crc_pool_c which is eventually sent towards the MSC According to GSM 8.08 3.1.1.2:If, on reception by the BSS of an ASSIGNMENT REQUEST message allocating a circuit, the circuit pool implied by the CIC is compatible with the channel type indicated (that is, the pool supports at least one of the radio resource types indicated by the channel type), but the BSS still wishes to change the circuit pool, it sends an ASSIGNMENT FAILURE with the cause "switch circuit pool" and the "circuit pool list

Documents

AMR Optimization Guidelines - Ver01.02 - Jan06.ppt