half rate & amr description

8/13/2019 Half Rate & AMR Description

1/21

13.May 2006

HUAWEI TECHNOLOGIES Co., Ltd.

www.huawei.com

HUAWEI Confidential

Security Level: Internal

Huawei HR and AMR

Introduction


2/21

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 2

Huawei Half Rate

Huawei AMR


3/21


4/21


HR - Assignment Principle

Different MSs support different rates. The assignment principle of radio resource is as

follows:

For the MSs that support full rate and half rate, the full rate is assigned preferentially

to improve the voice quality when the network is idle. The half rate is assigned

preferentially to hold more users when the network is busy. Whether the

network is busy or not is judged by comparing the channel seizure ratio andconfigured threshold (TCH Traffic Thrsh (%)): If the channel seizure ratio is

high than the threshold, the network is busy. Otherwise, the network is idle.

For the half rate call, the single channel is assigned preferentially to reduce the

fragment.

When the rate is enough to meet the service requirement, the channels on the TRXs

that do not allow the rate adjustment are assigned preferentially. The channelson the TRXs that allow rate adjustment are reserved for later use. This way

can ensure the maximum use of the channel resources.


5/21


Two Channel Allocation Strategies

There are two channel assignment strategies: MSC channel assignment

strategy and BSC channel assignment strategy.

MSC channel assignment strategy

Assign the channel according to the MSC request. If the request from MSC is

"TCHF preferred", assign the full rate channel preferentially. If it is "TCHH

preferred", assign the half rate channel preferentially.

BSC channel assignment strategy

When the assignment request sent from MSC is "Full rate TCH preferred" or"

Half rate TCH preferred", BSC assigns the proper channel according to the

availability of idle full rate channel in the cell and the allowance of MSC.

For the call that uses the half rate preferentially, the single channel isassigned preferentially to reduce the fragment.

If a cell has multiple TRXs, the channels on the TRXs that do not allow the

rate adjustment are assigned preferentially.


6/21


Rate Adjustment Principle

The adjustment principle is as follows:

Before assign the channel, determine whether to adjust the rate

or not according to the channel resources in the cell. If yes,

assign the channel to the current call after adjusting the rate.

That is, adjust the rate in real time.


7/21HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 7

Assignment request for full rate only

Full rate available

Assignmentrequest for TCHF

only

Assign full rate

channel

Couple channel

available

Convert couple channel tofull rate channel and then

assign the converted

channel

Initiate intracell handover toform couple channel, and

then convert the couple

channel to full rate channelto assign

Requestreject

Yes

Yes

Yes

No

No

No

more than one halfrate channel


8/21


Assignment request for half rate

only/preferentially

Single channel available

Half rateassignment

request

Assign half ratechanel

Couple channel availableAssign the half rate

channel on thecouple channel

Full rate channelavailable

Convert the full rate channel

into couple channel and thenassign the half rate channel

on the couple channel

Assignmentfails

Yes

Yes

Yes

No

No

No


9/21


10/21


HR Related Parameters

Channel seizure ratio = (Average num. of busy TCHF + Average num. of busy TCHH/2)/

(Average num. of availabe TCHF + Average num. of available TCHH /2) x 100


11/21


HR Related Traffic Statistic

BSC Measurement Function

Cell Measurement Function (2)

Half Rate Call Drop Measurement

Half Rate Receiving Quality Measurement

Half Rate Receiving Level Measurement

Overlaid/Underlaid Subcell Measurement


12/21


Huawei Half Rate

Huawei AMR


13/21


AMR - DefinitionThe Adaptive Multi Rate (AMR)is a set of multiple voice Codec algorithms. The BTS

and MS can automatically choose a proper Codec algorithm according to the actualradio environment to adjust the rate. Thus the voice quality can be improved.

Different Codec algorithm generates different rate voice code stream.

The AMR is only used in voice service. It is not used in the data service or signaling

service. Thus, the AMR is not considered when process the signaling of data

service or signaling service.

Full Rate AMRIt supports full rate channel AMR voice coding and decoding and includes 8 voice

rates: 12.2k (GSM EFR), 10.2k, 7.95k, 7.40k (IS-641), 6.70k, 5.90k, 5.15k, 4.75k;

The full rate AMR can adjust the coding rate according to the radio quality indication

(RQI). The coding rate is adjusted in the active coding set (ACS).

Half Rate AMR

It supports half rate channel AMR voice coding and decoding and includes 5 voice

rates: 7.40k (IS-641), 6.70k, 5.90k, 5.15k, 4.75k;

The half rate AMR can adjust the coding rate according to the radio quality

indication (RQI). The coding rate is adjusted in the ACS.


14/21


AMR FR MOS

Exper iment 1a - Test Results

1.0

2.0

3.0

4.0

5.0

Condi t ions

MOS

EFR12.210.27.957.46.75.95.154.75

EFR 4.01 4.01 3.65 3.05 1.5312.2 4.01 4.06 4.13 3.93 3.44 1.4610.2 4.06 3.96 4.05 3.80 2.047.95 3.91 4.01 4.08 3.96 3.26 1.437.4 3.83 3.94 3.98 3.84 3.11 1.396.7 3.77 3.80 3.86 3.29 1.875.9 3.72 3.69 3.59 2.205.15 3.50 3.58 3.44 2.434.75 3.50 3.52 3.43 2.66

No Errors C/I=16 dB C/I=13 dB C/I=10 dB C/I= 7 dB C/I= 4 dB C/I= 1 dB


15/21


AMR HR MOS

Experim ent 1b - Test Results

1.0

2.0

3.0

4.0

5.0

Condit ions

MOS

EFR7.957.46.75.95.154.75FRHR

EFR 4.21 4.21 3.74 3.34 1.587.95 4.11 4.04 3.96 3.37 2.53 1.607.4 3.93 3.93 3.95 3.52 2.74 1.786.7 3.94 3.90 3.53 3.10 2.22 1.215.9 3.68 3.82 3.72 3.19 2.57 1.335.15 3.70 3.60 3.60 3.38 2.85 1.844.75 3.59 3.46 3.42 3.30 3.10 2.00FR 3.50 3.50 3.14 2.74 1.50

3.35 3.24 2.80 1.92

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


16/21


AMR call set up process

Y

Deciding whether to assign

channel that supports AMR

function

Finishes AMR call set up

Deciding whether to

support AMR functionNormal Call

N

BSC receives the assigningrequest sent by MSC

Y

NNormal Call


17/21


Start and Close AMR Service Activated coding set

You can set different ACS, coding rate adjustment threshold and hysteresis and

initial coding rate according to the cells.

Add cell-level call statistical metrics.

TC query

You can inquire the TC support capability through the BSC maintenance console:

whether it supports the various voice Codec algorithms

Dynamic configuration function

Codec Mode Report

You can inquire the current coding mode used by a specified channel in real time.

The system outputs the coding mode and C/I information (RQI) used during the

inquiry period.

Intracell HR

FR HandoverThe system controls the balance between the cell capacity and the quality through

the intra-cell HR-FR handover based on RQI.

Different Power Control Methods

The AMR call and the non-AMR call use different power control parameters but the

same algorithm.


18/21


Call Process and Intracell Parameters

No. Parameter

1 TRX supports AMR or not

2 Active coding set

3 Full rate UL rate adjustment threshold (0 - 3)

4 Full rate UL rate adjustment hysteresis (0 - 3)

5 Full rate DL rate adjustment threshold (0 - 3)

6 Full rate DL rate adjustment hysteresis (0 - 3)

7 Half rate UL rate adjustment threshold (0 - 3),

8 Halfrate UL rate adjustment hysteresis (0 - 3),

9 Half rate DL rate adjustment threshold (0 - 3)

10 Half rate DL rate adjustment hysteresis (0 - 3)

No. Parameter

1 Intracell TCHF-TCHH handover statistics time

2 Intracell TCHF-TCHH lasting time

3 Handover threshold from TCHF to TCHH

4 Handover threshold from TCHH to TCHF


19/21


Circuit Pool 27

Service Type Explanation

FR speech version1 Full rate voice version 1, usually called FR.

FR speech version2 Full rate voice version 2, usually called EFR.

FR speech version3 Full rate voice version 3, codec algorithm used in full rate channel.

HR speech version1 Half rate voice version 1, usually called HR.

HR speech version3 Half rate voice version 3, codec algorithm used in half rate channel.


20/21


Typical Case

A user starts AMR function as follows:

In the MSC side, choose the Full rate speech version 3 and Half

rate speech version 3.

Configure the A interface protocol phase as Phase II+.

Configure the A interface circuit to support the AMR function.

It is recommended to configure the circuit pool as 27.

Configure the TRX to support the AMR function.

Configure the AMR call processing parameter.

Configure the AMR power control parameter.

Configure intracell TCHF-TCCH handover data.


21/21


Related Traffic Statistic

No. Item name

1 Successful TCH assignments(FR SV1, excluding directed retry)



2. Cell performance measurement (2)

No. Item name

1 Successful TCH assignments(HR SV1, excluding directed retry)



1. Cell performance measurement

3. Call allocation by TA measurement function

4. Average RQI based on TA value

half rate & amr description

Documents