Zte Umts Amr-nb & Amr-wb Feature Guide

AMR-NB & AMR-WB WCDMA RAN

Feature Guide

AMR-NB & AMR-WB Feature Guide

ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. I


Version Date Author Approved By Remarks

V4.5 2010-10-

15

Hu Xingxing/

Huang He Guo tian

© 2010 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or

used without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information of the document is

subjected to change without notice.


ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. II

TABLE OF CONTENTS

1 Functional Attribute ............................................................................................ 1

2 Overview ............................................................................................................. 1

2.1 Function Introduction ............................................................................................. 1

2.1.1 CS Conversational RAB for AMR Speech ............................................................ 3

2.1.2 WB-AMR Speech Support .................................................................................... 3

2.1.3 AMR Rate Controlling ............................................................................................ 4

2.1.4 TrFO ...................................................................................................................... 4

3 Technical Description ........................................................................................ 5

3.1 CS AMR Voice and Session Service Bearer ........................................................ 5

3.1.1 Implementation Mechanism of CS AMR Voice and Session Service Bearer Function ................................................................................................................ 5

3.1.2 Signaling Flow of AMR Service ............................................................................. 6

3.2 AMR-WB Voice Service ........................................................................................ 8

3.2.1 Implementation Mechanism of AMR-WB Functions ............................................. 8

3.3 Dynamic AMR Adaptation ................................................................................... 10

3.3.1 Classification of Dynamic AMR Adaptation......................................................... 10

3.3.2 Dynamic AMR Adaptation Based on Single-Link Transmission Power ............. 11

3.3.3 Dynamic Adjustment Triggered by Resource Congestion ................................. 14

3.3.4 Dynamic Adjustment Triggered by Load............................................................. 15

3.4 TrFO Support ...................................................................................................... 15

3.4.1 OoBTC Outband Codec Control......................................................................... 16

3.4.2 IuUP Initialization ................................................................................................. 17

3.4.3 IuUP Rate Control ............................................................................................... 17

4 Parameters and Configuration........................................................................ 19

4.1 Parameter List of AMR Dynamic Rate Adjustment ............................................ 19

4.1.1 Configuration of AMR Dynamic Rate Adjustment Parameters........................... 20

5 Counter and Alarm ............................................................................................ 26

5.1 Counter List ......................................................................................................... 26

5.2 Alarm List ............................................................................................................ 30

6 Glossary ............................................................................................................. 30


ZTE Confidential Proprietary © 2010 ZTE Corporation. All rights reserved. III

FIGURES

Figure 3-1 Signaling Flow of AMR Service ................................................................................ 7

Figure 3-2 UE Transmission Power Measurement Event Report (Trigger Time is fixed to be 100ms) ...................................................................................................................................... 12

Figure 3-3 NodeB DTCP Measurement Event Report (Hysteresis Time is fixed to be 100ms) .................................................................................................................................................. 14

Figure 3-4 Flow of OoBTC Outband Codec Control ............................................................... 16

Figure 3-5 IuUP Initialization..................................................................................................... 17

Figure 3-6 Flow of IuUP Rate Control ...................................................................................... 18

TABLES

Table 2-1 AMR-NB Rate Classification...................................................................................... 2

Table 2-2 AMR-WB Rate Classification .................................................................................... 2

Table 4-1 Parameter List ......................................................................................................... 19


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

1 Functional Attribute

System version: [RNC V3.09, OMMR V3.09, Node B V4.09, OMMB V4.09]

Attribute: [Optional]

NEs involved:

UE NodeB RNC MSCS MGW SGSN GGSN HLR

√ - √ √ √ - - √

Note:

*-: No NE is involved.

*√: An NE is involved.

Dependency: [None]

Mutual exclusion: [None]

Remarks: [None]

2 Overview

2.1 Function Introduction

The present 3GPP employs narrowband AMR (AMR-NB) and wideband AMR (AMR-WB).

For the AMR-NB, the speech channel bandwidth is limited to 3.7 kHz, and the sampling

frequency is 8,000 Hz. For the AMR-WB, the speech channel bandwidth is up to 7 kHz,

and the sampling frequency is up to 16,000 Hz. The AMR-WB has better speech quality

than the AMR-NB, although the two modes have the same frame length of 20ms.

AMR is introduced into the 3G system based on the following considerations :

By means of the AMR Control (AMRC), voice rate can be reduced to improve voice

quality. In addition, system load can be effectively lightened. In the case of certain

radio load, if users want to obtain the optimal subjective feeling of voice quality, the

most suitable AMR is not the maximum rate, but a suitable medium rate. By

weighing load, the AMRC can achieve the following goals:

The AMRC can reduce an AMR when load is heavy. This lightens system load

and improves voice quality.

The AMRC can increase an AMR when load is light. In this way, QoS is greatly

improved.



When uplink coverage is limited, AMR can be reduced to effectively widen uplink

coverage. In initial WCDMA network construction, both uplink coverage and downlink

capacity are limited; therefore, it is especially important to widen uplink coverage.

The Adaptive Multi-Rate (AMR) is also called the AMR-NB (Narrowband). This service has

three service RBs, and can provide eight speech rates and two mute rates, as shown in

Table 2-1:

Table 2-1 AMR-NB Rate Classification

AMR

Codec Mode

Total Number

of Bits

Sub-

flow 1

Sub-

flow 2

Sub-

flow 3

Codec Mode

AMR 4.75 kbps 95 42 53 0 AMR_4.75

AMR 5.15 kbps 103 49 54 0 AMR_5.15

AMR 5.9 kbps 118 55 63 0 AMR_5.90

AMR 6.7 kbps 134 58 76 0 AMR_6.70

AMR 7.4 kbps 148 61 87 0 AMR_7.40

AMR 7.95 kbps 159 75 84 0 AMR_7.95

AMR 10.2 kbps 204 65 99 40 AMR_10.20

AMR 12.2 kbps 244 81 103 60 AMR_12.20

AMR SID 39 39 0 0 AMR_SID

GSM-EFR SID 43 43 0 0 GSM-EFR SID

*SID (Silence Descriptor)

AMR-NB voice coding is divided into three sub-flows out of consideration for the

importance of information and error tolerance in voice coding. Each sub-flow requires its

own QoS assurance. Sub-flow 1 is the most important. Sub-flow 2 comes next. Sub-flow 3

is the least important. Sub-flow 1 needs better channel coding at an air interface to

guarantee its accuracy. No data rate is the coding in the case of mute. SID uses this

frame to indicate that current voice is not activated.

AMR-WB is short for Adaptive Multi-Rate Wideband. This service was introduced in 1999

in order to provide better speech quality and speech reproducibility. It can be applied both

in 3G system and GSM system.

Unlike AMR-NB, the AMR-WB has only two service RBs and provides nine speech rates

and one mute rate, as shown in the Table 2-2 below:

Table 2-2 AMR-WB Rate Classification

AMR-WB

Codec Mode

Total Number

of Bits

Sub-

flow 1

Sub-

flow 2

Sub-

flow 3

Codec Mode



AMR-WB

Codec Mode

Total Number

of Bits

Sub-

flow 1

Sub-

flow 2

Sub-

flow 3

Codec Mode

1.75 40 40 0 0 AMR-WB_SID*

6.60 132 54 78 0 AMR-WB_6.60

8.85 177 64 113 0 AMR-WB_8.85

12.65 253 72 181 0 AMR-WB_12.65

14.25 285 72 213 0 AMR-WB_14.25

15.85 317 72 245 0 AMR-WB_15.85

18.25 365 72 293 0 AMR-WB_18.25

19.85 397 72 325 0 AMR-WB_19.85

23.05 461 72 389 0 AMR-WB_23.05

23.85 477 72 405 0 AMR-WB_23.85

*SID (Silence Descriptor)

Like the AMR-NB, the AMR-WB sub-flow 1 contains the most important information of

speech, with 12-bit CRC protection added on the air interface. The sub-flow 2 contains less

important speech information, without CRC protection on the air interface.

2.1.1 CS Conversational RAB for AMR Speech

ZTE equipment supports all the eight AMRs: 12.2kbps, 10.2kbps, 7.95kbps, 7.4kbps,

6.7kbps, 5.9kbps, 5.15kbps, and 4.75kbps. What rate (s) to be used is same as the rate(s)

in RAB Assignment from CN. ZTE equipment supports DTX and SID.

The RAB parameters of ZTE RAN equipment, used to bear session AMR services, follow

the definition in the 3GPP TS 34.108.

2.1.2 WB-AMR Speech Support

ZTE RAN equipment supports all the nine speech rates of WB-AMR session, that is,

23.85Kbps, 23.05Kbps, 19.85Kbps, 18.25Kbps, 15.85Kbps, 14.25Kbps, 12.65Kbps,

8.85Kbps, 6.6Kbps, together with the mute rate 1.75 Kbps. The rate-(s) to be used is the

same as the rate(s) in RAB Assignment from CN. ZTE RNC enables and disables the

function of WAMR by the parameter WAMRSUPIND.

ZTE RNC does not support RAB negociation between AMR-NB and AMR-WB. When the

AMR-WB can not be established because of resources congestion, it is not supported to

establish AMR-NB by RAB negociation.

The RAB parameters of ZTE RAN equipment, used to bear session AMR-WB services,

follow the definition in the 3GPP TS 34.108.



2.1.3 AMR Rate Controlling

In WCDMA system, the radio environment between UE and a base station always

changes. When a UE is far away from the base station or the radio environment degrades,

the base station or UE is bound to transmit at a higher power under the action of closed-

loop power control in order to guarantee the QoS of AMR service. The power change and

power increase at this time may result in sharp increase in power and further deterioration

of the radio environment. As a result, the system capacity decreases. Even when the

power is increased to even a certain limit value, QoS requirements of service can not be

satisfied.

ZTE RNC equipment can monitor the uplink transmission power of UE in a UE internal

measurement report or the downlink transmission power of a Node B dedicated

measurement report base station. When the uplink or downlink transmission power rises

to a certain threshold, the RNC will automatically adjust this user's AMR to reduce the

power necessary for service. That is, a conversation is most probably kept going by

reducing voice quality. When the radio environment between UE and the base station is

good and the transmission power of the base station or UE decreases to a certain

threshold, AMR can be increased to provide users with better voice quality as long as

other users' feeling and system performance are not affected.

In addition, when a cell evaluated by means of downlink transmission power and uplink

interference has high downlink load and uplink load, ZTE RNC equipment can lighten the

cell load by reducing the AMR of some low-priority users, so as to accommodate more

users.

The actual AMR which can be adjusted by the RNC must belong to the AMR code set

configured for users by the CN during call establishment. The voice quality when low-rate

AMR coding is used is not as good as that when high-rate AMR coding is used, but low-

rate AMR coding has higher capacity (number of users) and wider coverage than high-rate

AMR coding. Analysis of simulation result shows that there is about 30% coverage radius

gain when the lowest AMR (4.75Kbps) instead of the highest AMR (12.2Kbps) is used.

When the lowest AMR is used, a cell will accommodate twice as many users as those

when the highest AMR is used.

2.1.4 TrFO

WCDMA employs AMR compressed voice encoding. The maximum encoding rate is

12.2kbit/s. At the R99 stage, TDM bearer is used between CS core network devices, and

voice must employ 64kbit/s PCM encoding. One very important function of the R99 MSC is

voice Transcoder (TC), which converts the AMR voice codes of a mobile terminal into PCM

codes and transmits them over a network. The calls between mobile users require two

voice encoding/decoding conversions, that is, AMR-PCM-AMR. Frequent

encoding/decoding reduces voice quality.



In view of this, the 3GPP organization has introduced the Tandem Free Operation (TFO)

and Transcoder Free Operation (TrFO) in the R4 protocol to avoid voice encoding/decoding.

Meantime, the TFO and TrFO help save the transmission network bandwidth between core

networks. The differences between both technologies are as follows: The TFO still needs

TC resource. After call establishment, a direct connection is established between the TCs

of the calling and called MSCs by means of in-band signaling negotiation to bypass

encoding/decoding. The TrFO does not need any TC resource at all. It means that outband

signaling encoding/decoding function (OoBTC) is used during call establishment to

implement consistent voice encoding/decoding negotiation between UE and network.

The TFO technology is implemented in the core network equipment. It does not need the

participation of RAN equipment. The TrFO technology requires that RAN equipment should

support outband voice encoding negotiation and the processing related to a user plane.

Both the TFO and TrFO can be used for AMR-WB encoding.

ZTE RAN equipment supports the TrFO function and complies with the 3GPP TS 23.153

and TS 25.415.

3 Technical Description

3.1 CS AMR Voice and Session Serv ice Bearer

3.1.1 Implementation Mechanism of CS AMR Voice and Session Service

Bearer Function

Selection of AMR-NB Rates

Function description: The 3GPP protocol defines eight speech rates and two mute

rates for AMR-NB, which supports the speech rate up to 12.2k. A database saves all

the rate configuration combinations of AMR-NB. According to the maximum rate of

AMR-NB in a CN assignment message, the RNC searches for corresponding

configuration information from the database.

Setup of Single AMR-NB Service and Concurrence with the PS Service

Function description: This function supports the setup of a single AMR-NB service

and the concurrency of AMR-NB and PS services.

Three Service RBs Established for the AMR-NB

Function description: This function supports service transformation by means of three

service RBs and reconfiguration.

Mobility of AMR-NB



Function description: This function supports soft handover, hard handover, and

relocation of AMR-NB service, and handover between 2G and 3G.

Directed Retry of the AMR-NB Service During Assignment

Function description: This function supports directed retry of AMR-NB service during

service assignment.

Default Configuration of AMR-NB rates: 12.2k, 12.2/7.95/5.9/4.75k and 7.95kbps.

Function description: This function supports the default configuration of AMR-NB

rates: 12.2k, 12.2/7.95/5.9/4.75k and 7.95kbps. It is used for the handover between

2G and 3G. The RNC establishes bearer according to this default configuration, sets

the default configuration in the HANDOVER TO UTRAN COMMAND message, and

sends this message to the UE through the 2G network.

RAB Modification of AMR-NB

Function description: This function does not support RNC initiates the RAB

modification of AMR-NB service; it supports CN initiates the RAB modification of

AMR-NB service. At present, the main scenarios for the CN to initiate RAB

modification to the AMR-WB include the TFO or TrFO conditions satisfied after

performance of handover, call forwarding, and intelligent service.

Dynamic Rate Adjustment for AMR-NB Service

Function description: This function supports dynamic rate adjustment for the AMR-

NB service triggered by link level, resource congestion, and load control. If the rate

adjustment threshold is met, the uplink rate is controlled by the RNC through the TFC

Control, and the downlink rate is controlled by the RNC through the Iuup reverse rate

control frame.

3.1.2 Signaling Flow of AMR Service

The setup flow of the AMR-WB and AMR-NB services is practically identical to that of

common services. The following example demonstrates the setup flow of the DCH service

in the synchronous mode.



Figure 3-1 Signaling Flow of AMR Service

6. Downlink Synchronisation

7. Uplink Synchronisation

UE Node B

Serving RNS

Serving

RNC

CN

RRC RRC

10. DCCH : Radio Bearer Setup Complete

NBAP NBAP 4. Radio Link Reconfiguration Ready

DCH-FP

NBAP NBAP 8. Radio Link Reconfiguration Commit

RRC RRC

9. DCCH : Radio Bearer Setup

Apply new transport format set

Select L1, L2 and Iu Data

Transport Bearer parameters

RANAP RANAP

11. RAB Assignment

Response

5. ALCAP Iub Data Transport Bearer Setup

2. ALCAP Iu Data

Transport Bearer Setup

Not required towards PS

domain

RANAP RANAP

1. RAB Assignment

Request

[Establishment]

NBAP NBAP 3. Radio Link Reconfiguration Prepare

[DCH Addition]

DCH-FP DCH-FP

DCH-FP

1 CN initiates establishment of the radio access bearer with RANAP message Radio

Access Bearer Assignment Request. Parameters: Radio Access Bearer

parameters, User Plane Mode, Transport Address, Iu Transport Association.

2 SRNC initiates set-up of Iu Data Transport bearer using ALCAP protocol. This request

contains the AAL2 Binding Identity to bind the Iu Data Transport Bearer to the Radio

Access Bearer (this step is not required towards PS domain).

3 SRNC requests its Node B to prepare establishment of DCH to carry the radio access

bearer (Radio Link Reconfiguration Prepare ). Parameters: Transport Format Set,

Transport Format Combination Set, Power control information.

4 Node B allocates resources and notifies SRNC that the preparation is ready (Radio

Link Reconfiguration Ready). Parameters: Transport layer addressing information

(AAL2 address, AAL2 Binding Id) for Iub Data Transport Bearer.



5 SRNC initiates the setup of Iub Data Transport Bearer using ALCAP protocol. This

request contains the AAL2 Binding Identity to bind the Iub Data Transport Bearer to

DCH.

6 The Node B and SRNC establish synchronism for the Iub and Iur Data Transport

Bearer by means of exchange of the appropriate DCH Frame Protocol frames

Downlink Synchronization.

7 The Node B and SRNC establish synchronism for the Iub and Iur Data Transport

Bearer by means of exchange of the appropriate DCH Frame Protocol frames Uplink

Synchronization.

8 NBAP message Radio Link Reconfiguration Commit is sent from SRNC to Node

B.

9 RRC message Radio Access Bearer Setup is sent by SRNC to UE. Parameters:

Transport Format Set, Transport Format Combination Set.

10 UE sends RRC message Radio Access Bearer Setup Complete to SRNC.

11 SRNC sends RANAP message Radio Access Bearer Assignment Response to CN.

3.2 AMR-WB Voice Service

3.2.1 Implementation Mechanism of AMR-WB Functions

Selection of AMR-WB Rates

Function description: ZTE through configuring the parameter WAMRSUPIND to

support the WB-AMR. The protocol 26.201 defines nine speech rates and one mute

rate for AMR-WB, which supports the maximum speech rate of 23.85k. The database,

with the AMR-WB service added, needs to save all AMR-WB rate configuration

combinations. According to the maximum AMR-WB rate in the message assigned by

the CN, the RNC searches for corresponding configuration information from the

database.

Note: The AMR-WB supports the voice bandwidth 50Hz-7kHz (the AMR-NB supports

the voice bandwidth 200Hz-3.4kHz); therefore, it has better voice quality than the

AMR-NB. Among the rates (23.85 kbps, 23.05 kbps, 19.85 kbps, 18.25 kbps, 15.85

kbps, 14.25 kbps, 12.65 kbps, 8.85 kbps, and 6.6 kbps) supported by the AMR-WB,

12.65kbps is the minimum rate that can achieve high-quality sound effects. The MOS

values of 6.6 kbps, 8.85 kbps, and 12.65 kbps apparently increase as the rate rises.

The MOS values of 12.65kbps, 14.25kbps, 15.85kbps, 18.25kbps, and 19.85kbps do

not apparently increase as the rate rises. So the rates of 12.65 kbps, 8.85 kbps, and

6.6 kbps are recommended by 3GPP.



Setup of Single AMR-WB Service and Concurrency with PS Service

Function description: The setup of a single AMR-WB service and the concurrency of

the AMR-WB and PS services are supported in the same way as the AMR-NB.

Three Service RBs Established for AMR-WB

Function description: Originally, the AMR-WB had only two service RBs while the

AMR-NB had three. For easy conversion between these two services through

reconfiguration, the 3GPP 25.331 and 34.108 specifications related to the AMR-WB

recommend configuration of three service RBs. The service sub-flow associated with

the third RB does not exist in the Iu port, and its actual data volume is 0 (0 × 60). The

RNC requires special processing, that is, the Iu port still supports two service sub-

flows, while the Iuup port needs to support the interconnection between two service

sub-flows and three service RBs.

Mobility of AMR-WB

Function description: Like the AMR-NB control policy, this function supports soft

handover, hard handover, relocation, and 2G-3G handover for the AMR-WB service.

This function uses the present parameters without new handover parameter added.

Directed Retry of AMR-WB Service During Assignment

Function description: Like the AMR-NB control policy, this function supports directed

retry of the AMR-WB service during service assignment. This function uses the

present parameters without new load balancing parameter added.

RAB Modification of AMR-WB

The RNC is not supported to initiate RAB modification to the AMR-WB service, while

the CN is supported to initiate the RAB modification to the AMR-WB, which is

performed in a way similar to that of the AMR-NB. At present, the main scenarios for

the CN to initiate RAB modification to the AMR-WB include the TFO or TrFO

conditions satisfied after performance of handover, call forwarding, and intelligent

service.

Dynamic Rate Adjustment for AMR-WB Service

Function description: Like the AMR-NB control policy, this function supports the

dynamic rate adjustment for the AMR-WB service triggered by link level, resource

congestion, and load control. This function uses the present parameters without new

load control parameter added. If the rate adjustment threshold is met, the uplink rate

is controlled by the RNC through the TFC Control, and the CN downlink rate is

controlled by the RNC through the Iuup reverse rate control frame.



3.3 Dynamic AMR Adaptation

3.3.1 Classification of Dynamic AMR Adaptation

According to the types of AMR, dynamic AMR adaptation is classified into AMR-NB

dynamic rate adjustment and AMR-WB dynamic rate adjustment. The AMR-WB rate

adjustment principles and steps are the same as those of the AMR-NB. In Iuup Version1,

ZTE RNC configures the AMR-NB rates by the parameters AmrNbMode0UseTag,

AmrNbMode1UseTag, AmrNbMode2UseTag, AmrNbMode3UseTag, AmrNbMode4UseTag,

AmrNbMode5UseTag, AmrNbMode6UseTag and AmrNbMode7UseTag. And ZTE RNC

configures AMR-WB rates by the parameters AmrWbMode0UseTag,

AmrWbMode1UseTag, AmrWbMode2UseTag, AmrWbMode3UseTag,

AmrWbMode4UseTag, AmrWbMode5UseTag, AmrWbMode6UseTag,

AmrWbMode7UseTag and AmrWbMode8UseTag. In Iuup Version2, ZTE RNC supports all

the AMR-NB and AMR-WB rates assigned by the CN. The AMR-NB and AMR-WB

dynamic rate adjustment based on single-link transmission power is controlled by the

configuration parameter AmrRncAdjust.

There are three types of AMR dynamic rate adjustment depending on the trigger

mechanisms:

AMR dynamic rate adjustment based on single-link transmission power

Due to inner-loop power control, uplink/downlink single-link transmission power varies

with the radio environment between the transmitting antennas of UE and NodeB.

When the radio environment degrades, the RNC should reduce the AMR to decrease

single-link transmission power to some degree. This serves to avoid heavy

uplink/downlink load of a cell resulting from increase in single-link transmission power

of AMR. When the single-link transmission power of AMR is low and the system load

is light, the RNC may increase the AMR to provide users with better voice quality by

making full use of system resources.

AMR rate adjustment triggered by the uplink/downlink overload of a cell

When a cell has uplink/downlink overload, the rate of uplink/downlink AMR service

should be reduced to decrease single-link transmission power, so as to lighten the

uplink/downlink load of the cell.

AMR rate adjustment triggered by the uplink/downlink resource congestion of a cell

Reduce the rate of uplink/downlink AMR service to lighten the uplink/downlink

resource congestion.

For these three trigger mechanisms, ZTE RNC can only adjust the rate of WB_AMR

services in the range of WB_AMR rates and can not adjust the rate of WB_AMR services



to the rate of WB_AMR. ZTE RNC can also only adjust the rate of NB_AMR services in

the range of NB_AMR rates.

In terms of the currently implemented functions and AMR service running, ZTE considers it

unnecessary to control an uplink rate with the granularity as accurate as TTI. Therefore,

ZTE has not yet implemented SRB5-based uplink AMR-WB rate adjustment.

3.3.2 Dynamic AMR Adaptation Based on Single-Link Transmission Power

AMR-WB dynamic rate adjustment and AMR-NB dynamic rate adjustment both involve

uplink direction and downlink direction. They have the same principle and use the same

threshold. In view of this, they are unified as AMR dynamic rate adjustment and described

here.

3.3.2.1 Uplink Direction (Based on the UE Transmission power)

Uplink AMR dynamic rate adjustment is based on the transmission power reported by UE.

Its operating principles are as follows:

When the uplink transmission power reported by UE exceeds the threshold

AMR_6A1 (invariably configured as 90% of the maximum transmission power

(MaxUlDpchPwr) of uplink DPCH), the AMR should be reduced by one level if the

current uplink AMR is not the minimum rate. If UE does not report any measurement

result or the reported uplink transmission power exceeds the threshold AMR_6B1

(invariably configured as 80% of the maximum uplink transmission power of UE) after

AMR reduction, we can concluded that the current transmission power is still

relatively high. In this case, the AMR should be further reduced level by level until the

uplink AMR is reduced to the minimum rate or the uplink transmission power reported

by UE is lower than the threshold AMR_6B1. If the uplink transmission power

reported by UE is lower than the threshold AMR_6B1, the AMR reduction will be

terminated.

When the uplink transmission power reported by UE is lower than the threshold

AMR_6B2 (invariably configured as 60% of the maximum transmission power

MaxUlDpchPwr of uplink DPCH), the AMR should be increased by one level if the

current uplink AMR is not the maximum rate and the uplink load of the system is

neither overloaded nor congested. If UE does not report any measurement result or

the reported uplink transmission power is lower than the threshold AMR_6A2

(invariably configured as 70% of the maximum uplink transmission power of UE) after

AMR increase, we can concluded that the current transmission power is still

relatively low. If the current uplink AMR is not the maximum rate and the uplink load

of the system is neither overloaded nor congested, the AMR should be further

increased level by level until the uplink AMR is increased to the maximum rate or the

uplink transmission power reported by UE exceeds the threshold AMR_6A2. If uplink

overload or resource congestion occurs during the increase of the AMR, it is



necessary to stop increasing the AMR. If the uplink transmission power reported by

UE exceeds the threshold AMR_6A2, the AMR increase will be terminated.

In order to avoid Ping-Pang AMR rate adjustment and the bad user experience due to

over frequent AMR rate adjustment, ZTE RNC restricts the two consective AMR rates

adjustment of the same direction by the parameter RevEvtDetectIme.

Figure 3-2 UE Transmission Power Measurement Event Report (Trigger Time is fixed to be

100ms)

Tx Power

Time

AMR_6A1

AMR_6A2

AMR_6B1

AMR_6B2

Report

6A

Report

6B

Report

6A

Report

6B

Trigger

TimeTrigger

Time

Trigger

Time

Trigger

Time

In the TrFO connection mode, the following judgments must be added on the basis of

the steps above:

If the target value of the AMR uplink rate increase originated from the local end is

smaller than or equal to the maximum uplink rate of the Iu port, it is allowed to

originate the rate increase, which then will be admitted by the admission control

module. If the target value of the rate increase originated from the local end is greater

than the maximum uplink rate of the Iu port, it is rejected to originate the rate

increase.

When the RNC receives the rate control command from the CN, the maximum rate is the

uplink target rate required by the CN. The admission control module determines the

maximum uplink rate allowed by the current local end according to the uplink load state of

the current cell and the single-link UE transmission power measurement report, and then

returns this rate in the rate control response command to the peer end. At the same time,

the RNC sends to the UE the TFC control command, requiring adjustment of the UE uplink

rate to a smaller one of the maximum uplink AMR available with the local end and the

maximum uplink AMR stated in the rate control command sent to the RNC from the CN.

3.3.2.2 Downlink Direction (Based on DTCP)

The downlink AMR adjustment is based on the special downlink transmission power

measurement report from Node B on the basic principles as follows:

When the special downlink transmission power reported by NodeB exceeds the

threshold AMR_E1 (invariably configured as 90% of the maximum downlink



transmission power (MaxDlDpchPwr) of AMR service), the downlink AMR should be

reduced by one level if the current downlink AMR is not the minimum rate. If the

special downlink transmission power reported periodically (The period is invariably

configured as four seconds) by NodeB after the downlink AMR reduction still exceeds

the threshold AMR_E1, we can concluded that the current transmission power is still

relatively high. And the downlink AMR should be further reduced to the minimum rate,

or the special downlink transmission power reported by NodeB is reduced to a value

lower than AMR_E2 (invariably configured as 80% of the maximum transmission

power (MaxDlDpchPwr) of downlink DPCH of AMR-WB service). If the special

downlink transmission power reported by NodeB is reduced to a value lower than the

threshold AMR_E2, the AMR reduction should be stopped.

When the special downlink transmission power reported by NodeB is lower than the

threshold AMR_F1 (invariably configured as 60% of the maximum transmission power

(MaxDlDpchPwr) of downlink DPCH of AMR service), the downlink AMR should be

increased by one level if the current downlink AMR is not the maximum rate and the

downlink load of the system is neither overloaded nor congested. If the special

downlink transmission power reported periodically (The period is invariably configured

as four seconds) by NodeB after the rate increase is still ultra-lower than the

threshold AMR_F1, we can concluded that the current transmission power is still

relatively low. If the current downlink AMR is not the maximum rate and the downlink

load of the system is neither overloaded nor congested, the downlink AMR should be

further increased level by level until the downlink AMR rises to its maximum or the

special downlink transmission power reported by NodeB is higher than the threshold

AMR_F2 (invariably configured as 70% of the maximum downlink transmission power

(MaxDlDpchPwr) of AMR service). If downlink overload or resource congestion occurs

during increase of the AMR rate, it is necessary to stop increasing the AMR rate. If

the special downlink transmission power reported by NodeB has exceeded the

threshold AMR_F2, the downlink AMR increase should be stopped.

In order to avoid Ping-Pang AMR rate adjustment and the bad user experience due to

over frequent AMR rate adjustment, ZTE RNC restricts the two consective AMR rates

adjustment of the same direction by the parameter RevEvtDetectIme.



Figure 3-3 NodeB DTCP Measurement Event Report (Hysteresis Time is fixed to be

100ms)

DTCP

Time

AMR_E1

AMR_F2

AMR_E2

AMR_F1

Report

AReport

B

Report

B

Report

A

Hysteresis

TimeHysteresis

Time

Hysteresis

Time

Hysteresis

Time

Periodic

Report

Periodic

Report

In the TrFO connection mode, the downlink rate depends on the downlink rate of the

Iu port; In a Mobile to Mobile call, the downlink rate depends on the uplink rate of the

peer end. Therefore, the downlink AMR-WB rate adjustment algorithm has the

following changes in comparison with the TrFO connection mode:

When the local end needs to adjust the downlink AMR, the RNC sends the adjusted

target rate through the rate control command to the CN, which then sends this rate

through the rate control command to the peer-end RNC. The returned rate control

response command contains the maximum uplink rate available with the peer end.

The peer end UE sends data at the smaller rate between the maximum uplink rate

supported by the peer end and the target rate required by the local end, so as to

complete downlink rate adjustment for the local end.

When the uplink rate of the peer end is decreased, the downlink rate of the local end

will be decreased accordingly.

When the uplink rate of the peer end is increased, the downlink rate of the local end will be

increased accordingly, resulting in change of the cell downlink load and the single-link

downlink D-TCP. The RNC should determine whether to decrease the increasing downlink

rate according to the cell downlink load and the single-link downlink D-TCP measurement

report. If the downlink rate should be decreased, the RNC sends to the CN the rate control

command that contains the maximum rate supported by the local end, so as to control the

downlink rate of the Iu port.

3.3.3 Dynamic Adjustment Triggered by Resource Congestion

In case of uplink/downlink resource congestion, the RNC should decrease the rate of some

AMR services by priority. When the uplink/downlink resource congestion is cleared, the

RNC should increase step by step the rate of any decreased AMR service that meets the

rate increase conditions described above. This dynamic adjustment also applies to WB-

AMR. For details, please refer to ZTE UMTS Congestion Control Feature Guide.



3.3.4 Dynamic Adjustment Triggered by Load

In case of uplink/downlink overload on a cell, the RNC should decrease the rate of some

AMR services by priority. When the uplink/downlink overload is cleared, the RNC should

increase step by step the rate of any decreased AMR service that meets the rate increase

conditions described above. This dynamic adjustment also applies to WB-AMR. For

details, please refer to ZTE UTMS Overload Control Feature Guide.

3.4 TrFO Support

At the R99 stage, voice at the CN CS employs 64kbit/s PCM encoding based on TDM

bearer. Therefore, the R99 MSC must have the voice TC function. But voice

encoding/decoding is apt to reduce voice quality. The calls between mobile users , in

particular, need dual voice encoding/decoding. If a codec is not used, voice quality will be

improved with network bandwidth saved.

At the R4 stage, voice encoding/decoding times can be reduced by establishing a TrFO

connection. The TrFO connection can be established throughout end-to-end process or

between some node of a call connection. For example, for a call between UMTS UE and a

fixed telephone, the TrFO connection only exists between UMTS UE and a core network.

The core network and RNC in the TrFO connection must support the IuUP V2. Otherwise,

no TrFO connection can be established. ZTE supports the IuUP V1 and IuUP V2. The RNC

will make a choice according to CN RAB assignment parameters.

The TrFO is implemented by employing the outband signaling encoding/decoding control

function (OoBTC). It is applicable to the calls between mobile networks and those between

a mobile network and an external network. When the same voice encoding/decoding type

is used between both call parties or between one call party and a node in the call

connection, the TrFO can transparently transmit compressed voice, which improves voice

quality and saves transmission bandwidth.

The node on both sides with a TrFO connection successfully established between them

will use completely the same common compressed voice encoding type negotiated at the

OoBTC stage. A codec must be inserted between a TrFO connection and a non-TrFO

connection to convert one encoding type into another. The implementation strategy of the

core network will, to the greatest extent, ensure that the insertion position can meet the

following requirements:

The insertion position should reduce the use of a transcoder and improve voice quality;

The insertion position should save transmission bandwidth, that is, it should prolong

the connection which uses compressed voice encoding data for transmission.

ZTE RNC controls the IuUP version between CN and RNC in the RAB assignment

procedure by the parameter IntraRatUpVer if CN support both IuUP Version1 and Version2.



And ZTE RNC controls the IuUP version between CN and RNC in 2G to 3G relocation

procedure by the parameter InterRatUpVer if CN support both IuUP Version1 and Version2.

For a UTRAN, its IuUP initialization, reverse initialization, IuUP rate control, and IuUP

reverse rate control are related to the TrFO process.

3.4.1 OoBTC Outband Codec Control

When a call is initiated, both call parties will negotiate about the codec so as to attempt to

establish a TrFO operation. In an IAM, the O-MSC carries the supported codec type list

and sends it to a transmission network. From the list, the transmission network deletes

the types that are not supported and sends it to a T-MSC. From the list, the T-MSC also

deletes the encoding types that are not supported. Then, the T-MSC selects an optimal

common encoding/decoding type, returns it to the transmission network and the O-MSC,

and notifies them of the currently selected encoding/decoding type. Meantime, the T-MSC

feeds back the encoding/decoding type that the Terminating UE supports to the O-MSC,

and begins to establish bearer on the basis of this codec. This flow is shown in Figure 3-4.

Figure 3-4 Flow of OoBTC Outband Codec Control

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 Established Bearer Established

The encoding type that the UE supports is transparently transmitted to the RNC by means

of Uplink Direct Transfer-> NAS Message-> Bearer Capacity. Then, the RNC transparently

transmits the encoding type to the MSC Server by means of Direct Transfer -> NAS



Indicator ->Bearer Capacity. During RAB assignment, the encoding/decoding type lists of

the calling and called parties are completely the same.

3.4.2 IuUP Initialization

IuUP initialization serves to define the mapping relationship (used at the data transmission

stage) between the RNC and CN on both sides of IuUP, including RAB sub-flow

combination, RFCIs, and SDU size of related RAB sub-flow.

If a bearer is successfully established, the CN will deliver an RAB assignment request

message to the RNC. The RNC in R4 version must support all the SDU sub-flow

combinations in the RAB assignment request message. That is, the content in the

initialization frame is a universal set of sub-flow combinations determined by RAB

assignment. Thus, the initialization frame will only be used to negotiate about IuUP version

information and RFCI correspondence (each RFCI corresponds to a sub-flow combination).

In the R99 version, this initialization process can only be initiated when the RNC receives

RAB assignment/modification or RNC relocation. In the R4 version, the CN can also start

this initialization process, called IuUP reverse initialization. IuUP initialization is shown in

Figure 3-5.

Figure 3-5 IuUP Initialization

*

Transfer Of User Data

CN/ RNC

INITIALISATION

((RFCI, SDU sizes[, IPTIs 2) ]) m )

INITIALISATION ACK

* can be repeated N INIT times 2) optional

RNC/ CN

In the RFCI set determined during IuUP initialization, the rate which corresponds to the

first RAB sub-flow combination is the maximum rate in the initialization answer direction

permitted by the local end when data transmission begins. The maximum rate must be

greater than the guaranteed rate and SID rate. It can be modified during IuUP rate control

after IuUP initialization. The rate greater than the guaranteed rate is called a controllable

rate. The rate lower than the guaranteed rate cannot be modified.

3.4.3 IuUP Rate Control

IuUP rate control serves to notify the peer IuUP protocol layer of the maximum rate at the

Iu port in the reverse direction of the rate control frame. In the R4 version, IuUP rate control



can be initiated by the RNC or the CN. In the R99 version, IuUP rate control can only be

initiated by the RNC.

As long as an IuUP entity is not suspended by other control flows, it can initiate rate

control. The controlled rates are all included in the RFC set determined during IuUP

initialization. These rates that correspond to the RFC should be higher than the guaranteed

rate. "Rate control" cannot be implemented in terms of the SID rate and the RFC lower

than the guaranteed rate because they themselves cannot be prohibited.

Figure 3-6 Flow of IuUP Rate Control

CN/ RNC

RNC/ CN

RATE CONTROL

(RFCI indicators)

RATE CONTROL ACK

(RFCI indicators)

Note: The rate control frame describes the use limit of an "RFC set", which is called "RFC

limit set" in the following parts.

In downlink direction, the RNC triggers the rate control frame, records the "RFC limit set"

(downlink direction), and monitors the implementation behavior of the CN. If the CN still

sends the data frame of the limited RFCI, the rate control frame must be resent. In uplink

direction, the IuUP module of the RNC receives the rate control frame and implements the

limit by means of TFC control.

The rate control initiated by the CN is as follows: After receiving a rate control message

from the RNC, the CN initiates rate control to the other party of a call to limit or open the

other party's uplink AMR level. Or the CN initiates a rate adjustment flow on its own

according to TrFO. For example, in SRNS relocation, the CN first performs reverse

initialization after a new RNC sends relocation detection to the CN. Then, the new RNC

initiates a process called immediate initialization. This serves to negotiate about the

maximum rate for data transmission between two IuUP entities which support TrFO.

The rate control initiated by the RNC is as follows: During dynamic AMR process, the RNC

adjusts the downlink AMR level according the downlink load of a cell or the dedicated TCP

measurement of an RL, and initiates rate control.

Compared with the encoding/decoding type negotiation before initialization, the IuUP rate

control is in-band rate control.



4 Parameters and Configuration

4.1 Parameter List of AMR Dynamic Rate

Adjustment

Table 4-1 Parameter List

Id Abbreviated Parameter name

1 AmrRncAdjust AMR Rate Adjustment Switch for RNC

2 MaxUlDpchPwr Maximum Allowed Uplink DPCH Transmission Power

3 MaxDlDpchPwr DPCH Maximum DL Power

4 AmrNbMode0UseTag AMR_NB 4.75k Use Tag








12 AmrWbMode0UseTag AMR_WB 6.60k Use Tag









21 RevEvtDetectIme

Time Interval for Consecutive AMR Adjustment of

Same Direction

22 WAMRSUPIND WB-AMR Speech Support Indicator

23 INTERRATUPVER Inter-RAT IuUP Version

24 INTRARATUPVER Intra-RAT IuUP Version



4.1.1 Configuration of AMR Dynamic Rate Adjustment Parameters

4.1.1.1 AmrRncAdjust

OMC Path

View -> Configuration Management -> RNC NE -> RNC Radio Resource Management

-> Basic Information-> AMR Rate Adjustment Switch for RNC

Parameter Configuration

When the value of this parameter is "Closed", AMR dynamic rate adjustment will not

be triggered due to UE internal measurement and NodeB special measurement; when

the value of this parameter is "Open", AMR dynamic rate adjustment will be triggered

due to the above-mentioned measurement. When this parameter is closed, AMR

voice quality remains unchanged in any case; when this parameter is opened, AMR

voice quality may slightly degrade according to different scenarios, but system

capacity can be increased accordingly.

4.1.1.2 MaxUlDpchPwr

OMC Path

View -> Configuration Management -> Rnc Radio Resource Management-> Advanced

Parameter Manager -> Power Control Related to Service and Diversity Mode ->

Maximum Allowed Uplink DPCH Transmission Power(dBm)


Background configuration value. The greater this value is, the higher the maximum

permissible uplink transmission power.

4.1.1.3 MaxDlDpchPwr

OMC Path

View -> Configuration Management ->Rnc Radio Resource Management-> Advanced

Parameter Manager ->Power Control Related to Service and Diversity Mode-> DPCH

Maximum DL Power


It represents the maximum permissible downlink DPCH transmission power. It is

related to service sub-class.



4.1.1.4 AmrNbMode0UseTag

OMC Path


-> Advanced Parameter Manager -> RNC Radio Resource Management -> AMR_NB

4.75k Use Tag


AMR_NB 4.75k using label 0: not using

1: using


OMC Path



5.15k Use Tag



1: using


OMC Path



5.90k Use Tag



1: using


OMC Path



6.70k Use Tag





1: using


OMC Path



7.40k Use Tag



1: using


OMC Path



7.95k Use Tag



1: using


OMC Path



10.2k Use Tag



1: using


OMC Path





12.2k Use Tag



1: using

4.1.1.12 AmrWbMode0UseTag

OMC Path


-> Advanced Parameter Manager -> RNC Radio Resource Management -> AMR_WB

6.60k Use Tag


AMR_WB 6.60k using label 0: not using

1: using


OMC Path



8.85k Use Tag



1: using


OMC Path



12.65k Use Tag





1: using


OMC Path



14.25k Use Tag


AMR_WB 14.25k using label 0:not using

1: using


OMC Path



15.85k Use Tag



1: using


OMC Path



18.25k Use Tag



1: using


OMC Path





19.85k Use Tag



1: using


OMC Path



23.05k Use Tag



1: using


OMC Path



23.85k Use Tag



1: using

4.1.1.21 RevEvtDetectIme

OMC Path


-> Advanced Parameter Manager -> RNC Radio Resource Management -> Time

Interval for Consecutive AMR Adjustment of Same Direction


It is used to set the time interval of two consecutive rate of AMR in the same direction.



4.1.1.22 WAMRSUPIND

OMC Path


-> RNC Configuration Supplement Parameters-> WB-AMR Speech Support Indicator


This parameter indicates whether support for WB-AMR voice services.

1.1.1.1 INTERRATUPVER

OMC Path


-> Advanced Parameter Manager -> RNC Configuration Supplement Information -

>Inter-RAT IuUP Version


Specifies the intra-RAT IuUP Version.

1.1.1.2 INTRARATUPVER

OMC Path


-> Advanced Parameter Manager -> RNC Configuration Supplement Information -

>Intra-RAT IuUP Version


Specifies the intra-RAT IuUP Version.

5 Counter and Alarm

5.1 Counter List Counter No. Description

C310030466 Number of CS AMR 12.2k in the best cell










C310030474 Number of CS WB AMR 23.85k in the best cell









C310030638 Number of CS AMR 12.2k in the non-best cell








C310030646 Number of CS WB AMR 23.85k in the non-best cell









C310063411 Number of CS AMR 12.2k in the DRNC cell








C310063419 Number of CS WB AMR 23.85k in the DRNC cell











C310040001 Holding time for the best cell,AMR12.2








C310040009 Holding time for the best cell,WB-AMR23.85









C310040075 Holding time for the non-best cell,AMR12.2








C310040083 Holding time for the non-best cell,WB-AMR23.85











C310073296 Holding time for the DRNC cell,AMR12.2








C310073304 Holding time for the DRNC cell,WB-AMR23.85




























5.2 Alarm List

No related alarm list.

6 Glossary

A

AMR Adaptive Multi-Rate

AMRC Adaptive Multi-Rate Control

AMR-NB Adaptive Multi-Rate Narrow-Band

AMR-WB Adaptive Multi-Rate Wide-Band

C

CN Core Network

D

D-TCP Dedicated Transmitting Carrier Power

I

IAM Initial Address Message

IuUP Iu User Plane

M

MSC Mobile Switch Center

N

NAS Non-Access-Stratum

O

OoBTC Out-of-Band Transcoder Control

P

PCM Pulse Code Modulation

PSTN Public Switched Telephone Network



Q

QoS Quality of Service

O-MSC Originating Mobile Switch Center

R

RAB Radio Access Bearer

RFC RAB sub-Flow Combination

RFCI RAB sub-Flow Combination Indicator

RL Radio Link

RX Receive

RNC Radio Network Controller

S

SCR Source Controlled Rate

SDU Service Data Unit

SID Silence Information Description

SRNC Serving RNC

T

TC Transcoder

TCP Transmitting Carrier Power

TFC Transport Format Combination

TFO Tandem Free Operation

T-MSC Terminating Mobile Switch Center

TrFO Transcoder Free Operation

TX Transmit

U

UMTS Universal Mobile Telecommunications System

Documents

Zte Umts Amr-nb & Amr-wb Feature Guide