ZGO-01-01-003 Adaptive Multi-Rate _AMR_ Codec V8.20 20091230.pdf

8/10/2019 ZGO-01-01-003 Adaptive Multi-Rate _AMR_ Codec V8.20 20091230.pdf

1/30

ZGO-01-01-003 Adaptive Multi-

Rate (AMR) CodecFeature Description


2/30


3/30

ZGO-01-01-003 Adaptive Multi-Rate (AMR) Codec

ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. 1


Version Date Author Approved By Remarks

V8.11 2009-02-26 Not open to the Third Party



2010 ZTE Corporation. All rights reserved.ZTE CONFIDENTIAL:This document contains proprietary information of ZTE and is not to bedisclosed or used without the prior written permission of ZTE.Due to update and improvement of ZTE products and technologies, information of the document issubjected to change without notice.


4/30


2 2010 ZTE Corporation. All rights reserved. ZTE ConfidentialProprietary

TABLE OF CONTENTS

1

Feature Attributey ...................................................................................................... 1

2 Overv iew ..................................................................................................................... 12.1 Feature Introduction ..................................................................................................... 12.2 Corelation with Other Features .................................................................................... 4

3 Technical Description ................................................................................................ 43.1 AMR Procedure ........................................................................................................... 43.2 Description of AMR Functions ..................................................................................... 73.3 Description of AMR Parameters .................................................................................. 83.3.1 ACS .............................................................................................................................. 83.3.2 Threshold and Hysteresis ............................................................................................ 93.3.3 ICM ............................................................................................................................ 10

3.3.4

Others ........................................................................................................................ 113.4 AMR with TrFO .......................................................................................................... 11

4 Parameters and Configurations .............................................................................. 134.1 Parameter List ........................................................................................................... 134.2 Parameter Configurations .......................................................................................... 16

5 Related Counters and Alarms ................................................................................. 205.1 Related Counters ....................................................................................................... 205.2 Related Alarms .......................................................................................................... 23

6 Engineering Guide ................................................................................................... 236.1 Application Scenario .................................................................................................. 23

6.2

Configuration Description .......................................................................................... 23

6.3 Network Impact .......................................................................................................... 23

7 Abbreviation ............................................................................................................. 24

8 Reference Document ............................................................................................... 24

FIGURES

Figure 1

AMR coding modes ....................................................................................................... 3Figure 2 AMR speech quality ....................................................................................................... 4

Figure 3 Message procedure of AMR on major system interfaces .............................................. 5

Figure 4 Speech Version Establishment Flow ............................................................................. 7

Figure 5 Definition of threshold and hysteresis during code mode adaptation ............................ 9

Figure 6 Out-of-band codec negotiation procedure ................................................................... 12

Figure 7 Windows for AMR Configuration-1 .............................................................................. 17

Figure 8 Windows for AMR FR Configuration ............................................................................ 18

Figure 9 Windows for AMR HR Configuration ........................................................................... 18


Figure 11 19

Figure 12

Windows for AMR Configuration-3 .............................................................................. 19


5/30




TABLES

Table 1 List of coding rate modes in ACS .................................................................................. 9

Table 2 Counter List for CS Basic Measurement ..................................................................... 20

Table 3 Counter List of Radio Resource Availability Measurement ......................................... 21

Table 4 Counter List of TCH/F Measurement ........................................................................... 21

Table 5 Counter List of TCH/H Measurement .......................................................................... 22


6/30


7/30



1 Feature Attributey

iBSC Version: [ZXG10 iBSC V6.20].

BTS Version: [Independent of BTS software and hardware platforms]

Property: [Optional function]

Related Network Element:

NE Name Involved Or Not Special Requirement

MS

BTS

BSC

MSC

MGW -

SGSN -

GGSN -

HLR -

Dependent Function: [None].

Exclusive Function: [None].

Note: [None].

2 Overview

2.1 Feature Introduction

As a second generation digital cellular communication system, Global System for Mobile

Communications has been widely used around the world. At present, voice services arethe major services in GSM. The development of voice services and coding technologiesis fuelled up by users' demand for high-quality voice communication services andoperators demand for capacity increase to reduce investment. Therefore, the AdaptiveMulti-Rate Codec (AMR) technology was introduced into ETSI standards in 1999.

Compared with the original GSM voice codec that adopts constant coding rate, AMRuses link adaptation to select the optimal channel mode (Full Rate (FR) or Half Rate(HR)) and source coding mode (differentiated by bit rate) for speech transmission basedon radio channel and transmission conditions, so as to offer the best trade-off betweenspeech quality and system capacity.

AMR contains the following two adaptive technologies:


8/30



1 Adaptive channel rate mode.

The channel rate mode only changes when a call is set up or MS enters a new cell.MSC allocates constant channel rate mode (FR/HR) for both communication parties

based on channel quality and utilization (for example, frequency and frequencyband utilization. When fewer frequency band is available, MSC will allocate lowerrate mode for new calls to balance the network capacity and service quality.). Thechannel rate mode, once established, will not change during conversation.

2 Adaptive source coding mode and channel coding mode

AMR performs adaptive change of source coding and channel coding modes duringconversion based on estimated channel quality, that is, adjust source coding andchannel coding rates while keeping total channel transmission rate unchanged.AMR adjusts channel coding rate (by providing extra bits) to ensure conversationquality by reducing source coding rate when channel conditions are bad andredundant bits in channel codes are insufficient to correct transmission error.

Contrarily, it increases source coding rate to enhance speech quality when channelconditions are good.

The algorithm adopted by AMR is Multi-Rate Algebraic Code Excited Linear Prediction(MR-ACELP). As a hybrid algorithm of CELP, MR-ACELP not only inherits generaltechnical features of CELP (for example, hybrid parameter analysis and excitationgeneration, and ABS), but also combines advantages of multiple speech-related hybridcoding algorithms in digital mobile communication to adapt to speech codingrequirements of different mobile networks.

AMR speech coding frames are 20 ms long. One frame contains 4 sub-frames, withsampling frequency of 8kHz (160 samples for 20 ms frames). AMR algorithmimplements coding/decoding (respectively relative to the downlink/uplink processing of

speech links) of consecutive 20 ms speech frames based on different rate modes.

As a part of coding data, the coding mode and speech coding data are both involved inchannel coding and are referred to as in-band information. According to the protocol,there are a total of 14 modes of the AMR codec, 8 are available in a full rate channel(FR) and 6 on a half rate channel (HR), as shown in Figure 1. In practice, a maximum of4 modes can be adopted whether in FR or HR. These four modes or less constitute theActive Codec Set (ACS).


9/30



Figure 1 AMR coding modes

AMR contains three core parameters:

ACS: refers to the Active Codec Set of AMR.

Threshold: refers to the threshold value for code change.

Hysteresis: refers to code change Hysteresis.

The latter two parameters are used to determine which rate mode is adopted.

AMR is of variable rate compared with other speech coding modes. It adjusts speechcoding rate based on equivalent Carrier-to-Interference Ratio (C/I) value to ensure thebest possible speech quality under different C/I values, as shown in Figure 2. AMR isenabled based on user requirements when channel conditions are bad.


10/30



Figure 2 AMR speech quality

2.2 Correlation with Other Features

This feature is functionally related to the following features:

ZGO-04-02-007 AMR Radio Link Timers

ZGO-03-02-006 Independent Threshold for Dynamic AMR HR-FR Conversion

ZGO-04-02-008 AMR Power Control

The specific descriptions are as follows:

Relation with AMR Radio Link Timers, Independent Threshold for Dynamic AMR HR-FR Conversion and AMR Power Control: These three features can only beimplemented when AMR is adopted.

3 Technical Description

3.1 AMR Procedure

Figure 3 shows the message procedure of AMR on major system interfaces.


11/30



Figure 3 Message procedure of AMR on major system interfaces

As shown in Figure 3, speech data frame is associated with Codec Mode Indication(CMI) in both uplink and downlink directions. The CMI is used at the receiving end toselect correct channel and source decoders, and it is also sent to TC to select correctsource decoding on mobile network.

BTS must estimate uplink channel quality for uplink coding adaptation, select optimalcoding for current propagation environment and send the information to MS over airinterface through a message.

MS must estimate downlink channel quality for downlink coding adaptation, and send amessage containing quality information to BTS. The quality information is mapped to acoding mode.

The coding mode is theoretically variable in each speech frame, but in practice, codingadaptation is performed at low rate due to transmission delay and necessary filteringduring adaptation. Each link may adopt different coding modes, but the same channeltype (FR or HR) must be adopted for uplink/downlink.

Channel type is selected during call setup or upon handover through radio resourcemanagement function and can be changed based on channel conditions duringconversation.

The calling procedures involved in AMR include: assignment, incoming inter-BSChandover, outgoing inter-BSC handover, and intra-BSC handover.

Assignment procedure is as follows:

MSC judges whether MS is AMR-capable based on MS support capability, call

service type, speech version allowed by MSC and No. of circuit pool of A interface

circuit.

MSC determines speech version set allowed in this call and send it to BSC through

an Assignment Request message.


12/30



BSC obtains the available speech versions by taking the intersection of speech

version set carried in the Assignment Request message and that supported by the

cell.

BSC selects a speech version of highest level from the available speech versions

as the final speech version based on allocated channel type.

If AMR speech codec is selected, BSC sends AMR service parameters to BTS

through channel activation command or mode modification command, and to MS

through assignment command or mode modification command. Upon receiving the

assignment command or mode modification command, MS returns an Assignment

Complete message to MSC. AMR call assignment procedure ends.

Incoming inter-BSC handover procedure is as follows:

MSC judges whether MS is AMR-capable based on MS support capability, call

service type, speech version allowed by MSC and No. of circuit pool of A interface

circuit.

MSC determines speech version set allowed in this call and send it to BSC through

an Assignment Request message.

BSC obtains the available speech versions by taking the intersection of speech

version set carried in the Assignment Request message from MSC and that

supported by the cell.

BSC selects a speech version of highest level from the available speech versions

as the final speech version based on allocated channel type.


through channel activation command. Upon receiving channel activation response

from BTS, BSC returns a handover request response message to MSC and sends

AMR service parameters to MS through handover command.

Outgoing inter-BSC handover procedure is as follows:

BSC handover decision algorithm initiates outgoing inter-BSC handover procedure, and

sends a HO RQD message to MSC, containing the speech version used in current call.

Intra-BSC handover procedure is as follows:

BSC handover decision algorithm initiates intra-BSC handover, and obtains the final

speech version in the same way described in assignment procedure.


through channel activation command and to MS through handover command.

Figure 4 shows speech version establishment flow.


13/30



Figure 4 Speech Version Establishment Flow

3.2 Description of AMR FunctionsAMR supports the following functions:

Support AMR-FR speech codec function, including 8 types of speech rates:

12.2kbit/s (GSM EFR)

10.2kbit/s

7.95kbit/s

7.40kbit/s (IS-641)

6.70kbit/s

5.90kbit/s

5.15kbit/s

4.75kbit/s

Support AMR-FR coding rate adjustment in ACS based on C/I values.

Support AMR-HR speech codec function, including 6 types of speech rates:


14/30



7.95kbit/s

7.40kbit/s(IS-641)

6.70kbit/s

5.90kbit/s

5.15kbit/s

4.75kbit/s

Support AMR-HR coding rate adjustment in ACS based on C/I values.

Note:

The coding rate 7.95kbit/s is supported only when IP transmission mode instead ofTDM is adopted on A interface.

Support cell-level enabling and disabling of AMR.

Support cell-level settings of different ACSs, coding rate adjustment threshold

values and hysteresis values and initial coding rates.

Support dynamic configuration of AMR enabling/disabling, ACS, coding rate

adjustment threshold, hysteresis and initial coding rate.

Support different radio link timers for AMR and non-AMR calls. For details, see

ZGO-04-02-007 AMR Radio Link Timers.

Support different threshold values for AMR HR-FR conversion and non-AMR HR-

FR conversion.

Support different power control strategies for AMR and non-AMR calls. For details,

seeZGO-04-02-008 AMR Power Control.

Support TFO and TrFO.

Support ACS change during handover rather than during channel hold.

3.3 Description of AMR Parameters

3.3.1 ACS

The ACS used in BSS and MS is defined through L3 signaling during call setup orhandover, and set through the parameters AMR-FR coding rate mode set (AmrFullAcs)or AMR-HR coding rate mode set (AmrHalfAcs). ACS contains a maximum of 4 codingmodes, as listed in Table 1.


15/30



Table 1 List of coding rate modes in ACS

Identifier Description

CODEC_MODE_1 It indicates the lowest coding mode (lowest bit rate) in

ACS.CODEC_MODE_2 It indicates next lowest mode if ACS contains more than

one mode.

CODEC_MODE_3 It indicates the third lowest mode if ACS contains morethan two modes.

CODEC_MODE_4 It indicates the highest mode if ACS contains fourmodes.

3.3.2 Threshold and Hysteresis

AMR coding mode is selected from ACS (generally containing one to four coding modes)based on one to three threshold values (parameter AmrThresholds) and hysteresis(parameter AmrHysteresis) during call setup. ACS, threshold and hysteresis are alldefined during call initiation.

Channel quality measurement and estimate are based on equivalent C/I. Both MS andBSS constantly adjust QI based on C/I norm, and CMR and CMC are judged based onquantized values of QI. Hysteresis is used to prevent frequency switching of CMR andCMC among different modes. The previously sent CMC (CMR) is used as the status ofcurrent adaptation logic, and upper and lower thresholds are defined for each status: ForCMC, lower threshold: THR_MC_Dn and upper threshold: THR_MC_Up; for CMR, lowerthreshold: THR_MR_Dn and upper threshold: THR_MR_Up. If the measurement valuefalls below the lower threshold, next CMC/CMR will request a lower coding rate. If the

measurement value rises above the upper threshold, next CMC/CMR will request ahigher coding rate. If the measurement value falls between upper and lower thresholds,CMC/CMR will retain current coding rate, as shown in Figure 5.

To avoid channel error and bit error, CMC, CMR and CMI must control the rate mode tochange stepwise (instead of mode skip) between adjacent modes unless because ofhandover or TFO.

CODEC_MODE_4

CODEC_MODE_3

CODEC_MODE_2

CODEC_MODE_1

C/I

THR_1 + HYST_1 = THR_MX_Up(1)

THR_1 = THR_MX_Dn(2)





Figure 5 Definition of threshold and hysteresis during code mode adaptation


16/30



The switch thresholds shall be given by network in consecutive order.

_1 _ 2 _ 3THR THR THR

_1 _1 _ 2 _ 2 _ 3 _ 3THR HYST THR HYST THR HYST + + +

Parameter Description Scope Numberof bits

THR_1/2/3 Lowest threshold for switching from j to j-1. 0-63 6

HYST_1/2/3 Hysteresis to obtain higher threshold from j to j+1. 0-15 4

Threshold (THR) is given in a step length of absolute value 0.5 dB. The thresholdbetween 0 and 63 must be mapped to normalized C/I:

When threshold and hysteresis parameters defined through L3 signaling are used,HYST_1/2/3 must be coded in a step length of 0.5dB:

3.3.3 ICM

The Initial Codec Mode (ICM) adopted during call setup and handover can be indicatedthrough L3 signaling. The value of ICM is judged through the parameters AMR codecmode (IsAmrICM) and AMR start codec mode (AmrStartMod). The clearly indicated

ICM must have higher priority than default ICM. The default value of ICM is defined asfollows:

If ACS contains:

One codec mode, then ICM is the initial codec mode.

Two or three codec modes, then ICM is the most robust (lowest bit rate) mode in the set.

Four codec modes, then ICM is the next most robust (next lowest bit rate) mode in theset. If the ACS changes during calling, then the default ICM will be used all the time untilanother clearly indicated ICM is received.


17/30



For example,

Assume ACS contains four bit rates of 12.2 kbit/s, 7.95 kbit/s, 6.70 kbit/s and 4.75 kbit/s:

Condition 1: IsAmrICM= Startmode, and AmrStartMode=1,

Then ICM=4.75 kbit/s.

Condition 2: IsAmrICM= Startmode, and AmrStartMode=2,

Then ICM = 6.70 kbit/s.

Condition 3: IsAmrICM=6.70 kbit/s,

Then AmrStartMode is invalid and ICM=6.70 kbit/s.

3.3.4 Others

The parameter AMR Noise Suppression (IsAmrNscb) is used to judge whether AMRnoise suppression is allowed.

3.4 AMR with TrFO

Transcoder Free Operation (TrFO), also known as Out-of-Band Transcoder Control(OoBTC), is a technology used to negotiate speech codec modes through out-of-bandcall control signaling during call setup. After negotiation, MSs can make calls with oneanother without using codec, and hence speech quality is improved. The out-of-bandnegotiation mechanism makes TC resources dispensable for TrFO, and thus savesprecious TC resources and reduces power consumption arising thereof. In addition,using TrFO in group carrier can save bandwidth because speech can be transmitted incore networks at the rate of AMR 12.2 kbps.

In A-interface over TDM mode, TRAU is located on BSS side. For voice services, itimplements codec conversion from 2G coding/decoding to TDM PCM, and for dataservices, it implements 64k for rate matching. MGW receives the PCM mode, andcoding/decoding algorithm is G.711. TC is not required when MGW accesses A interfaceterminal, and a TrFO call cannot be established in the call process.

In A interface over IP (AoIP) mode, TRAU is built in the MGW. Therefore, the voice

packets from BSS may include several types such as GSM HR, GSM FR, GSM EFR, FRAMR, and HR AMR.

For calls adopting GSM HR, GSM FR, and GSM EFR codec modes, TrFO calls arejudged based on the following conditions:

All streams of terminals at the stream layer are voice services.

The codec types of all streams of terminals at the stream layer are consistent.

For calls adopting HR AMR, FR AMR, UMTS AMR and UMTS AMR2 codec modes,TrFO calls are judged based on the following conditions:


18/30



All streams of terminals at the stream layer are voice services.

The codec types of all streams of terminals at the stream layer are consistent.

The UP Version of streams of UP-capable terminals at the stream layer supports 2.

The ACSs of all streams of terminals at the stream layer are consistent.

Generally, TrFO negotiation is implemented by MGW. At first, BSC performs channelallocation based on the ACS specified in the ASSIGNMENT REQUEST (Asssignment)or HANDOVER REQUEST (outgoing inter-BSC handover) message. The sequence ofchannel types and speech version represents the result of TrFO negotiationimplemented by MSC.

Then, BSC will make the final decision for channel allocation in terms of differentstrategy like requirement from MSC, BSS channel allocation strategy and busy status of

traffic, etc. Afterwards, BSC will send the selected channel type and speech version tothe MSC through the ASSIGNMENT COMPLETE and HANDOVER REQUESTACKNOWLEDGE messages based on the final decision. At this time, TrFOimplementation requirements may be met or may not be met. If its failed to meet therequirement on establishing TrFO call, then MSC will make MGW insert a pair of TCs todo the voice transcoding

Finally, BSC inserts TC unit in MGW.

Codec List (v, w, x, y, z)

Codec List (v, w, x, z)

O-MSC Transit T-MSC

O-MGW T-MGWTransit

MGW

Selected Codec = v, Available List (v, x, z, )

Selected Codec = v

Selected Codec = v

Selected Codec = v, Available

List (v, x, z, )

Selected Codec = v

Bearer EstablishedBearer Established

Figure 6 Out-of-band codec negotiation procedure

The TrFO negotiation procedure in MGW is illustrated in Figure 6, with details listed asfollows:

A calling MS sends a SETUP message carrying a codec list supported by the

calling UE to a calling MSC Server. At this moment, the out-of-band codec

negotiation procedure for TrFo call setup starts. Upon obtaining the codec list, the

calling MSC Server takes an intersection of ACSs supported by RNC and MGW,


19/30



and then sends an IAM message containing the supported codec list to the called

MSC Server. The codec list in the example is (v, w, x, y, z).

The intermediate switch can delete the codec types not supported by itself, for

example, y is deleted from the instance.

Upon obtaining the codec list (v, w, x, z) supported by the calling side, the called

switch calculates the codec list supported by RNC and MGW in connection with the

called MS, and that supported by the called UE, to acquire the available codec list

(ACL). In the above example, the ACL is (v, x, z), where, the first codec v

represents SC, that is, selecting codec v as the current codec type.

The called MSC Server sends the negotiated SC and ACL to the caller's network to

inform MGW, and sets up a user-plane bearer by using codec V. Upon receiving the

SC and ACL, the calling MSC Server If there is a codec is available in ACL, the call

will be set up with inserting TC and then MSC could modify the codec type during

the call to rebuild the TrFO call.

4 Parameters and Configurations

4.1 Parameter ListFull Name AMR Ful l Active Codec Set

Abbreviation AmrFullAcs

Description

The code has 8 bits. The code has 8 bits. Bit 8:12.2 kbps;Bit 7: 10.2 kbps; Bit 6: 7.95 kbps; Bit 5: 6.70 kbpsBit 2: 5.15 kbps; Bit 1: 4.75 kbps.Yes represents 1 and No represents 0.Default code is 10101010 (that is 170)

Value RangeFrom 4.75 kbit/s, 5.15 kbit/s, 5.90 kbit/s, 6.70 kbit/s, 7.40kbit/s, 7.95 kbit/s, 10.2 kbit/s to 12.2 kbit/s, value range isYes/No.

Unit None

Default Default is [No, Yes, No, Yes, No, Yes, No, Yes] in order.

Management

ObjectCell

Full Name Threshold of AMR

Abbreviation AmrThresholds


20/30



Description

The threshold of changing AMR mode includes sevenfactors: AmrThresholds1, AmrThresholds2,AmrThresholds3, AmrThresholds4, AmrThresholds5,AmrThresholds6, AmrThresholds7. Also,the following

restricted conditions shall be met:AmrThresholds1AmrThresholds2AmrThresholds3AmrThresholds4AmrThresholds5Amr-Thresholds6AmrThresholds7 AmrThresholds1AmrHysteresis1AmrThresholds2 AmrHysteresis2AmrThresholds3 AmrHysteresis3Amr-Thresholds4 AmrHysteresis4AmrThresholds5AmrHysteresis5AmrThresholds6 AmrHysteresis6AmrThresholds7 AmrHysteresis7

Value Range

Including mode 1, 2, 3, 4, 5, 6, and 7. Value range is0~63.

0: 0.0 dB;

1: 0.5 dB;

2: 1.0 dB

63: 31.5 dB

Unit None

Default 691318243139

Management

ObjectCell

Full Name Hysteresis of AMR

Abbreviation AmrHysteresis

Description

The hysteresis of changing AMR mode includes sevenfactors: AmrHysteresis1, AmrHysteresis2,AmrHysteresis3, AmrHysteresis4, AmrHysteresis5,AmrHysteresis6, AmrHysteresis7. Also, thefollowing restricted conditions shall be met:AmrThresholds1AmrHysteresis1AmrThresholds2AmrHysteresis2AmrThresholds3 AmrHysteresis3AmrThresholds4 AmrHysteresis4Amr-Thresholds5 AmrHysteresis5AmrThresholds6AmrHysteresis6AmrThresholds7AmrHysteresis7

Value Range

Including mode 1, 2, 3, 4, 5, 6, and 7. Value range is0~15.

0: 0.0 dB;

1: 0.5 dB;

2: 1.0 dB

15: 7.5 dB

Unit None


21/30



Default 3435556

Management

ObjectCell

Full Name Initial codec mode

Abbreviation IsAmrICM

Description Use the coding mode specified by Startmode

Value Range Startmode codec, Initial codec mode

Unit None

Default Startmode codec

Management

ObjectCell

Full Name Start mode

Abbreviation AmrStartMode

Description Startmode codec mode

Value Range

When four values are configured as "No" within 8elements in "AMR full Active Codec Set (AmrFullAcs)"interface, value range is 1~4;

When five values are configured as "No" within 8elements in "AMR full Active Codec Set (AmrFullAcs)"interface, value range is 1~3;

When six values are configured as "No" within 8elements in "AMR full Active Codec Set (AmrFullAcs)"

interface, value range is 1~2;

When seven values are configured as "No" within 8elements in "AMR full Active Codec Set (AmrFullAcs)"interface, value range is 1;

When all values are configured as "No" for 8 elementsin "AMR full Active Codec Set (AmrFullAcs)" interface,value range is null;

The values are as follows:

1: Select the coding mode with lowest bit rate as the

initial coding mode.

2: Select the coding mode with the second lowest bitrate, if there is more than one coding mode.

3: Select the coding mode with the third lowest bitrate, if there is more than two coding modes.

4: Select the coding mode with the fourth lowest bitrate, if there are more than three coding modes.

Unit None

Default 1


22/30



Management

ObjectBSC

Full Name Enable noise contro l

Abbreviation IsAmrNscb

Description

This parameter defines whether AMR noise control isenabled, that is, to suppress background noise and keeporiginal voice quality.No: Enable noise suppression;Yes: Disable noise suppression;

Value Range Yes/No

Unit None

Default No

Management

Object Cell

Full Name AMR Half Active Codec Set

Abbreviation AmrHalfAcs

Description

The code has 8 bits. Bit 6~ Bit 8: reserved; Bit 5: 7.40kbps; Bit 4: 6.70 kbps Bit 2: 5.15kbps; Bit 1: 4.75 kbps.Yes represents 1 and Norepresents 0.Four coding modes could be set at the most. Default codeis 00011110 (that is 30).

Value RangeFrom 4.75 kbit/s, 5.15 kbit/s, 5.90 kbit/s, 6.70 kbit/s to 7.40kbit/s, value range is Yes/No.

Unit None

Default Default is [No, Yes, Yes, Yes, Yes] in order.

Management

ObjectCell

Full Name IP A AMR Start Mode

Abbreviation IPAAmrStartMode

Description AMR Start Mode when IP A configured

Value Range Default rate, start rate will be the largest rate of ACS

Unit None

Default Default rate

Management

ObjectCell

4.2 Parameter Configurations

In the configuration resource tree window, select [OMC GERAN Subnetwork BSC


23/30



Managed Element Config Set BSC Function BTS Config BTS ID Cell ID],

as shown in the following figure;

Figure 7 Windows for AMR Configuration-1


24/30



Figure 8 Windows for AMR FR Configuration

Figure 9 Windows for AMR HR Configuration

3 In the configuration resource tree window, select [OMC GERAN Subnetwork

BSC Managed Element Config Set BSC Function BTS Config BTS ID


25/30



Cell ID], in the tag on the left side, to configure the AMR functions, as shown in

the following figure;


4 In the tag for [AMR half method params], set the following parameters,

AMR Half Active Codec Set

Threshold of AMR

Hysteresis of AMR


5 In the tag for [AMR Full method params], set the following parameters,

AMR Full Active Codec Set


26/30



Threshold of AMR

Hysteresis of AMR


5 Related Counters and Alarms

5.1 Related Counters

Table 2 Counter List of CS Basic Measurement

Counters What it counts

C900060026Number of TCH/F allocation success for assignment (speechversion3)

C900060027Number of TCH/F allocation failure for assignment (speechversion3)

C900060145Number of TCH/F allocation failure due to BTS connectionfailure for assignment (speech version3)

C900060146Number of TCH/F allocation failure due to BIU connectionfailure for assignment (speech version3)

C900060147Number of TCH/F allocation failure due to TCU connectionfailure for assignment (speech version3)

C900060164Number of TCH/F allocation failure due to channel activationfailure for handover(speech version3)

C900060165Number of TCH/F allocation failure due to BTS connectionfailure for handover (speech version3)


27/30



Counters What it counts

C900060166Number of TCH/F allocation failure due to BIU connectionfailure for handover (speech version3)

C900060167 Number of TCH/F allocation failure due to TCU connectionfailure for handover (speech version3)

C900060191 Number of TCH/H allocation failure due to channel activationfailure for assignment (speech version3)

C900060192 Number of TCH/H allocation failure due to BTS connectionfailure for assignment (speech version3)

C900060193 Number of TCH/H allocation failure due to BIU connectionfailure for assignment (speech version3)

C900060194 Number of TCH/H allocation failure due to TCU connectionfailure for assignment (speech version3)

C900060195 Number of TCH/H allocation failure due to channel activation

failure for handover (speech version3)

C900060196 Number of TCH/H allocation failure due to BTS connectionfailure for handover (speech version3)

C900060197 Number of TCH/H allocation failure due to BIU connectionfailure for handover (speech version3)

C900060198 Number of TCH/H allocation failure due to TCU connectionfailure for handover (speech version3)

Table 3 Counter List of Radio Resource Availability Measurement

Counter What It Counts

C901080017 TCH/H busy time(SpeechVer3)

C901080018 TCH/H congestion time

Table 4 Counter List of TCH/F Measurement


C901260050Number of TCH/F allocation attempts by BSC for assignment(speech version 3)

C901260056 Number of TCH/F allocation attempts by BSC for handover(speech version 3)

C901260057 Number of TCH/F allocation success by BSC for handover(speech version 3)

C901260102Number of data TCH/F allocation failure for assignment due toTIPB connection failure (Speech version 3)

C901260103Number of data TCH/F allocation failure for assignment due toResource request to iTC failure (Speech version 3)

C901260104Number of data TCH/F allocation failure for handover due toTIPB connection failure (Speech version 3)

C901260105 Number of data TCH/F allocation failure for handover due to


28/30




Resource request to iTC failure (Speech version 3)

C901260118 Number of TCH/F allocation failure due to request AIPB

resource failure for assignment (speech version 3)

C901260119 Number of TCH/F allocation failure due to request UDP portfailure for assignment (speech version 3)

C901260120 Number of TCH/F allocation failure due to AIPB connectionfailure for assignment (speech version 3)

C901260121 Number of TCH/F allocation failure due to request AIPBresource failure for handover (speech version 3)

C901260122 Number of TCH/F allocation failure due to request UDP portfailure for handover (speech version 3)

C901260123 Number of TCH/F allocation failure due to AIPB connectionfailure for handover (speech version 3)

Table 5 Counter List of TCH/H Measurement


C901270050 Number of TCH/H allocation attempts for assignment (speechversion 3)

C901270051 Number of TCH/H allocation success for assignment (speechversion 3)

C901270056 Number of TCH/H allocation attempts by BSC for handover(speech version 3)

C901270057 Number of TCH/H allocation success for handover (speechversion 3)

C901270094 Number of TCH/H allocation failure for assignment due to TIPBconnection failure (Speech version 1)

C901270095 Number of TCH/H allocation failure for assignment due toResource request to iTC failure (Speech version 1)

C901270096 Number of TCH/H allocation failure for handover due to TIPBconnection failure (Speech version 1)

C901270097 Number of TCH/H allocation failure for handover due toResource request to iTC failure (Speech version 1)

C901270118 Number of TCH/H allocation failure due to request AIPB

resource failure for assignment (speech version 3)

C901270119 Number of TCH/H allocation failure due to request UDP portfailure for assignment (speech version 3)

C901270120 Number of TCH/H allocation failure due to AIPB connectionfailure for assignment (speech version 3)

C901270121 Number of TCH/H allocation failure due to request AIPBresource failure for handover (speech version 3)

C901270122 Number of TCH/H allocation failure due to request UDP portfailure for handover (speech version 3)

C901270123 Number of TCH/H allocation failure due to AIPB connectionfailure for handover (speech version 3)


29/30



5.2 Related Alarms

There are no relevant alarms for this function.

6 Engineering Guide

6.1 Application Scenario

This feature can be applied in important business areas, special areas with higherrequirements for speech quality, and areas with poor radio environments. The followings the typical application scenarios of AMR:

1. AMR can be used in BSS system with TDM stream and IP data.

2. If the core network (CN) connects two/more BSS systems which are original fromdifferent films, AMR also has an effect on this kind of system (CN with different BSSsystems).

3. When 3G RAN and 2G RAN want to have a conversation, they can use AMR.

AMR speech coding can improve the speech codec transmission rate, ease the conflictbetween speech quality and system capacity, thus enhancing the speech conception.

6.2 Configuration Description

This feature does not involve the adjustment of iBSC or BTS hardware configuration.

6.3 Network Impact

1 Impacts on network

AMR speech codec features a stronger anti-interference capability than commonspeech codec, so it can deliver better speech quality. In terms of speech quality,

AMR HR-FR lies between HR and FR, and only the network performance indexesof uplink/downlink RQ and MOS values are affected. The uplink/downlink RQ andMOS values of AMR HR-FR also lie between HR and FR.

Furthermore, the activation of AMR enables uplink and downlink channels to adoptthe coding schemes that are more applicable to the actual radio environment, thusreducing the call drop rate during service initiation.

2 Impacts on NEs

This feature has no impact on the capacity of iBSC and BTS.


30/30


7 AbbreviationAbbreviations Full Characteristics

ACS Active Codec SetAMR Adaptive Multi-Rate Codec

AoIP A-interface over IP

BSC Base Station Controller

BTS Base Transceiver Station

CELP Code-Excited Linear Predictive

C/I Carrier/Interference

CMC Code Mode Command

CMI Codec Mode Indication

CMR Code Mode Request

FR Full Rate

HR Half Rate

MOS Mean Opinion Score

MS Mobile Station

MSC Mobile services Switching Centre

QI Quality Indicator

RQ Receive Quality

8 Reference Document[[None]

ZGO-01-01-003 Adaptive Multi-Rate _AMR_ Codec V8.20 20091230.pdf

Documents

Transcript of ZGO-01-01-003 Adaptive Multi-Rate _AMR_ Codec V8.20 20091230.pdf