AMR Huawei

AMR GBSS13.0

Feature Parameter Description

Issue 03

Date 2012-06-30

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2012. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior

written consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their respective

holders.

Notice

The purchased products, services and features are stipulated by the contract made between Huawei and

the customer. All or part of the products, services and features described in this document may not be

within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,

information, and recommendations in this document are provided "AS IS" without warranties, guarantees or

representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the

preparation of this document to ensure accuracy of the contents, but all statements, information, and

recommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

Bantian, Longgang

Shenzhen 518129

People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

http://www.huawei.com/

mailto:[email protected]

GSM BSS

AMR Contents

Issue 03 (2012-06-30) Huawei Proprietary and Confidential

Copyright © Huawei Technologies Co., Ltd

i

Contents

1 Introduction ................................................................................................................................ 1-1

1.1 Scope ............................................................................................................................................ 1-1

1.2 Intended Audience ........................................................................................................................ 1-1

1.3 Change History .............................................................................................................................. 1-1

2 Overview of AMR ....................................................................................................................... 2-1

3 Technical Description .............................................................................................................. 3-1

3.1 Inband Signaling ............................................................................................................................ 3-1

3.2 Speech Rate Adjustment ............................................................................................................... 3-2

3.3 Rate Adjustment Threshold Adaptation ......................................................................................... 3-5

3.4 Um Interface Speech Frame Repairing ......................................................................................... 3-6

3.5 AMR Power Control ....................................................................................................................... 3-6

3.6 Handover ....................................................................................................................................... 3-7

3.7 E-CODER ...................................................................................................................................... 3-7

4 Related Features ....................................................................................................................... 4-1

5 Impact on the Network ............................................................................................................ 5-1

5.1 AMR FR ......................................................................................................................................... 5-1

5.1.1 Impact on System Capacity .................................................................................................. 5-1

5.1.2 Impact on Network Performance .......................................................................................... 5-1

5.2 AMR HR ........................................................................................................................................ 5-1






5.4 AMR Coding Rate Threshold Adaptive Adjustment ....................................................................... 5-1






5.6 AMR Radio Link Timer .................................................................................................................. 5-2



5.7 AMR FR/HR Dynamic Adjustment ................................................................................................. 5-2



6 Engineering Guidelines ........................................................................................................... 6-1

6.1 When to Use AMR ......................................................................................................................... 6-1

GSM BSS

AMR Contents



ii

6.1.1 AMR FR and AMR HR .......................................................................................................... 6-1

6.1.2 AMR Power Control .............................................................................................................. 6-1

6.1.3 AMR Coding Rate Threshold Adaptive Adjustment .............................................................. 6-1

6.1.4 Um Interface Speech Frame Repairing ................................................................................ 6-1

6.1.5 AMR Radio Link Timer .......................................................................................................... 6-1

6.1.6 AMR FR/HR Dynamic Adjustment ........................................................................................ 6-1

6.2 Information to Be Collected ........................................................................................................... 6-1

6.2.1 AMR FR and AMR HR .......................................................................................................... 6-1






6.3 Network Planning .......................................................................................................................... 6-2

6.3.1 AMR FR and AMR HR .......................................................................................................... 6-2






6.4 Deploying AMR FR and AMR HR .................................................................................................. 6-3

6.5 Deploying AMR Power Control ...................................................................................................... 6-3

6.6 Deploying AMR Coding Rate Threshold Adaptive Adjustment...................................................... 6-3

6.7 Deploying Um Interface Speech Frame Repairing ........................................................................ 6-3

6.8 Deploying AMR Radio Link Timer ................................................................................................. 6-3

6.9 Deploying AMR FR/HR Dynamic Adjustment ............................................................................... 6-3

7 Performance Optimization ..................................................................................................... 7-1

7.1 AMR FR and AMR HR ................................................................................................................... 7-1

Table 7-1 Counters related to channel usage for the AMR FR and AMR HR traffic ... 7-1


7.3 AMR Coding Rate Threshold Adaptive Adjustment ....................................................................... 7-1


7.5 AMR Radio Link Timer .................................................................................................................. 7-1

Monitoring ...................................................................................................................................... 7-1

Table 7-2 Counters related to AMR FR and AMR HR call drops ...................................... 7-2

7.6 AMR FR/HR Dynamic Adjustment ................................................................................................. 7-2

8 Parameters ................................................................................................................................. 8-1

9 Counters ...................................................................................................................................... 9-1

10 Glossary .................................................................................................................................. 10-1

GSM BSS

AMR Contents



iii

11 Reference Documents ......................................................................................................... 11-1

GSM BSS

AMR 1 Introduction



1-1

1 Introduction

1.1 Scope

This document describes the AMR feature. It describes adaptive multirate (AMR) speech rate adjustment, rate adjustment threshold adaptation, Um interface speech frame repairing, AMR power control, enabling of Tandem Free Operation (TFO) and Discontinuous Transmission (DTX) in the case of AMR, handover between AMR FR and AMR HR, enhanced coding (E-CODER), and impacts on KPIs .

1.2 Intended Audience

This document is intended for:

Personnel who need to understand AMR

Personnel who work with Huawei products

1.3 Change History

This section provides information on the changes in different document versions.

There are two types of changes, which are defined as follows:

Feature change: refers to the change in the AMR feature of a specific product version.

Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues

The document issues are as follows:

03(2012-06-30)

02 (2011-10-30)

01 (2011-03-31)

Draft A (2011-01-15)

03(2012-06-30)

This is the third commercial release of GBSS13.0.

Compared with issue 02 (2011-10-30), issue 03 (2012-06-30) incorporates the changes described in the following table.

Change Type Change Description Parameter Change

Feature change None None

Editorial change Added the description for4 Related Features,5 Impact on the Network and 6 Engineering Guidelines.

None

02 (2011-10-30)

This is the second commercial release of GBSS13.0.

Compared with issue 01 (2011-03-31), issue 02 (2011-10-30) incorporates the changes described in the following table.

GSM BSS

AMR 1 Introduction



1-2


Feature change Deleted the description for DTX and TFO. Deleted the following parameters:

FRDLDTX

FRULDTX

HRDLDTX

HRULDTX

NBAMRTFOSWITCH

Editorial change Added the description for AMR half-rate (HR) speech rate adjustment and related parameters.

Added the following parameters:

ULTHH1

ULHYSTH1

ULTHH2

ULHYSTH2

ULTHH3

ULHYSTH3

01 (2011-03-31)

This is the first release of GBSS13.0.

Compared with issue draft A (2011-01-15) of GBSS13.0, issue 01 (2011-03-31) of GBSS13.0 has no change.

Draft A (2011-01-15)

This is the draft release of GBSS13.0.

Compared with issue 01 (2010-06-30) of GBSS12.0, issue draft A (2011-01-15) of GBSS13.0 incorporates the changes described in the following table.


Feature change

Added sections 3.4 "Um Interface Speech Frame Repairing" and 3.9 "E-CODER."

Added the following parameters:

UMSFRSWITCH

EncodeMode

Editorial change

None None

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GSM BSS

AMR 2 Overview of AMR



2-1

2 Overview of AMR

AMR is an adaptive multi-rate voice coding/decoding, which is termed full-rate speech version 3 and half-rate speech version 3 in GSM specifications. AMR enables the BTS and the MS to automatically select an appropriate coding/decoding rate from the specified ACS according to the interference level in the radio environment. This enhances the capability and the speech quality of the wireless communication system.

AMR is classified into AMR FR and AMR HR. AMR specifies eight speech coding rates. Table 2-1 lists the speech coding rates supported by AMR FR and AMR HR. (GBFD-115501 AMR FR, GBFD-115502 AMR HR)

Table 2-1 AMR speech coding rates

Coding Rate AMR FR AMR HR

4.75 kbit/s √ √

5.15 kbit/s √ √

5.90 kbit/s √ √

6.70 kbit/s √ √

7.40 kbit/s √ √

7.95 kbit/s √ √

10.2 kbit/s √ -

12.2 kbit/s √ -

NOTE

-: not supported

√: supported

Note: When SERVICEMODE of the BTS is set to IP or HDLC, Huawei BSS supports the AMR coding rate of 7.95 kbit/s. When SERVICEMODE of the BTS is set to TDM, Huawei BSS does not support the AMR HR coding rate of 7.95 kbit/s.

As listed in Table 2-1, the coding rates of 12.2 kbit/s and 10.2 kbit/s are supported by only the AMR FR channel. The other six types of coding rates are supported by both the AMR FR channel and the AMR HR channel.

Each ACS contains a maximum of four coding schemes. One coding scheme corresponds to one speech coding rate.

For an AMR FR call, the ACS contains a maximum of four speech coding rates of the eight rates listed in Table 2-1.

For an AMR HR call, the ACS contains a maximum of four speech coding rates of the six rates listed in Table 2-1.

When AMR is enabled on the network, the BSC selects an ACS and then a coding scheme from the ACS during the call establishment or the handover procedure. Meanwhile, the MS and the BTS continuously measure the receive level, receive quality, and C/I ratio. According to the measurement results, the MS and the BTS continuously evaluate the interference level in the radio environment. The BTS then adjusts the speech coding rates of the MS and the BTS according to the evaluated interference level through the inband signaling.

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GSM BSS

AMR 3 Technical Description



3-1

3 Technical Description

3.1 Inband Signaling

Inband signaling is a type of signaling through which user data and control information are transmitted on the same channel. In this document, the inband signaling refers to the AMR control information such as the CMR and CMI that is transmitted through certain bits in the header of the Transcoder and Rate Adaptor Unit (TRAU) frame.

During a call, the MS and the BTS continuously measure the interference level experienced by the signals and analyze the measurement results. Based on the measurement results, the AMR control information is then exchanged through the inband signaling to enable the BTS to adjust the speech coding rate involved in the ongoing speech service.

The AMR control information is transmitted through certain bits in the header of the TRAU frame. The AMR control information can be classified into the following types:

Downlink Codec Mode Request (DL CMR): The DL CMR occupies two bits in the header of the TRAU frame. It is used by the MS to send the recommended DL coding scheme to the BTS.

Downlink Codec Mode Indication (DL CMI): The DL CMI occupies two bits in the header of the TRAU frame. It is used by the BTS to send the current DL coding scheme to the MS.

Uplink Codec Mode Command (UL CMC): The UL CMC occupies two bits in the header of the TRAU frame. It is used by the BTS to send the UL coding scheme that should be used by the MS to the MS.

Uplink Codec Mode Indication (UL CMI): The UL CMI occupies two bits in the header of the TRAU frame. It is used by the MS to send the current UL coding scheme to the BTS.

Uplink Maximum Codec Mode Command (UL Max CMC): The UL Max CMC occupies three bits in the header of the TRAU frame.

To implement AMR coding scheme adaptation, a Mode Control Entity is used in both the MS and the BTS, as shown in Figure 3-1.

Figure 3-1 AMR coding scheme adaptation

Speech

Decoder

Channel

Decoder

Mode

Control

Entity

Speech

Encoder

Channel

Encoder

MS

DL MEAS

DL CMR

UL CMC

Channel

Encoder

Mode

Control

Entity

Channel

Decoder

BTS

DL CMI

UL CMC

DL CMI

UL CMC

DL CMR

UL CMI

UL MEAS

Speech

Encoder

Speech

Decoder

TRAU

UL Max CMC

As shown in Figure 3-1, the AMR coding scheme adaptation procedure is as follows:

GSM BSS




3-2

Uplink direction

The BTS measures the receive quality of the UL speech and generates the Uplink Measurement (UL MEAS).

The Mode Control Entity of the BTS updates the UL CMC based on the UL MEAS generated by the BTS.

The BTS instructs the MS to change the UL coding scheme through the UL CMC.

The MS changes the UL coding scheme as indicated by the UL CMC and then sends the UL CMI to the BTS to inform the BTS of the new UL coding scheme.

Downlink direction

The MS measures the receive quality of the DL speech and generates the Downlink Measurement (DL MEAS). The Mode Control Entity of the MS converts the DL MEAS into the recommended DL coding scheme. Then, the MS sends the recommended DL coding scheme to the BTS through the DL CMR.

The Mode Control Entity of the BTS updates the DL speech coding scheme based on the recommended DL coding scheme sent from the MS.

The BTS instructs the MS to use the new DL coding scheme through the DL CMI.

3.2 Speech Rate Adjustment

AMR speech rate adjustment is the process that the AMR coding scheme of a call on a channel frequently changes to adapt to the variations of the interference level in the radio environment.

Each AMR coding scheme has an adjustment threshold, which is used to select the coding scheme that is best suited to the C/I ratio or Bit Error Rate (BER) of the interference level in the radio environment. To avoid the constant changes of the coding scheme, the process of hysteresis is introduced. The value of the threshold ranges from 0 to 63. Value 1 indicates 0.5 dB, and value 2 indicates 1 dB. The rest may be deduced by analogy. The value of the hysteresis ranges from 0 to 15. The hysteresis value complements the threshold.

Figure 3-2 shows the procedure for AMR coding scheme adjustment.

Figure 3-2 Procedure for AMR coding scheme adjustment

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)





THR_N: AMR Coding Rate adj.thN (1≤N≤3)

HYST_N: AMR Coding Rate adj.hystN (1≤N≤3)

GSM BSS




3-3

CODEC_MODE_1: indicates the lowest-bit-rate coding scheme

CODEC_MODE_2: indicates the coding scheme whose bit rate is higher than only that of CODEC_MODE_1 (assume that there is more than one coding scheme in the ACS)

CODEC_MODE_3: indicates the coding scheme whose bit rate is the second highest in the ACS (assume that there are more than two coding schemes in the ACS)

CODEC_MODE_4: indicates the coding scheme whose bit rate is the highest in the ACS (assume that there are four coding schemes in the ACS)

Assume that the currently used coding scheme is CODEC_MODE_3. As shown in Figure 3-2, when the C/I ratio is greater than THR_3 plus HYST_3, the coding scheme is changed to CODEC_MODE_4; when the C/I ratio is smaller than THR_2, the coding scheme is changed to CODEC_MODE_2.

The procedure for AMR UL speech rate adjustment is similar to the procedure for AMR DL speech rate adjustment. The AMR UL coding scheme is adjusted by the BTS, and the AMR DL coding scheme is adjusted by the MS. Figure 3-3 shows the procedure through which the BTS adjusts the AMR UL coding scheme.

GSM BSS




3-4

Figure 3-3 Procedure through which the BTS adjusts the AMR UL coding scheme

N

Y

N

Select the initial AMR

coding rate.

Start

Enable AMR rate

adjustment algorithm?

Perform filtering for C/I

or BER data.

Filter value >

(THR_N+HYST_N)?

Filter value <

THR_N-1?

Keep the coding

rate unchanged.

MS must use the AMR coding

rate of a higher level.

MS must use the AMR coding

rate of a lower level.

Adjust the coding

rate.

End

Y

N

Y

THR_N: AMR UL Coding Rate adj.thN (1≤N≤3)

HYST_N: AMR UL Coding Rate adj.hystN (1≤N≤3)

The procedure through which the BTS adjusts the AMR UL coding scheme shown in Figure 3-3 is described as follows:

1. During AMR FR call establishment, INITCDMDF specifies which coding scheme in ACTCDSETF should be used to make a call. During AMR HR call establishment, INITCDMDH specifies which coding scheme in ACTCDSETH should be used to make a call.

2. The RATECTRLSW parameter specifies whether the AMR speech rate is adjusted. The setting of this parameter is described as follows:

− When this parameter is set to Algorithm I, it indicates that the BSC adjusts the AMR speech rate based on the C/I ratio.

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3-5

− When this parameter is set to Algorithm II, it indicates that the BSC adjusts the AMR speech rate based on the Bit Error Rate (BER).

− When this parameter is set to None, it indicates that the AMR rate adjustment is disabled.

3. If the RATECTRLSW parameter is set to Algorithm I or Algorithm II, the AMR coding scheme adapts to the change of the radio environment during the call according to the configured threshold and hysteresis.

The following description takes the adjustment of the AMR FR coding scheme as an example.

The currently used coding scheme is CODEC_MODE_1.

− If the filter value is greater than ULTHF1 plus ULHYSTF1, the peer end needs to adjust the coding scheme to CODEC_MODE_2.

− In other cases, the coding scheme remains unchanged.



− If the filter value is smaller than ULTHF1, the peer end needs to adjust the coding scheme to CODEC_MODE_1.









4. If the coding scheme is to be adjusted, the BTS sends a UL CMC to the MS. The procedure for adjusting the UL coding scheme by the BTS is complete.

The AMR HR calls use the same coding scheme policy adjustment as that used by the AMR full-rate calls; however, they use different parameters. The AMR half-rate coding scheme involves the following parameters: ULTHH1, ULHYSTH1, ULTHH2, ULHYSTH2, ULTHH3, and ULHYSTH3.

3.3 Rate Adjustment Threshold Adaptation

Generally, network planning engineers set the ACS, threshold parameters, and hysteresis parameters for a cell according to the evaluation of the radio channel quality. When the radio channel quality keeps changing or the quality evaluation is inaccurate, the parameter settings do not meet the requirements of the speech services in the cell. In this case, the appropriate AMR coding scheme cannot be selected for a call, and the quality of the speech services is affected.

The AMR rate adjustment threshold adaptation function enables the BSC to monitor the speech quality in real time and to adaptively modify the threshold parameters. Therefore, an appropriate AMR coding scheme can always be selected for the call. (GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment)

The principle for uplink adaptive adjustment of the threshold is the same as that for downlink adaptive adjustment of the threshold.


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GSM BSS




3-6

When the BSC sends a channel activation or a speech coding scheme modification message to the BTS, the channel activation or the speech coding scheme modification message carries LTFERUPTH, LTFERLOWTH, LTFERTGT, and LTTHADJFA, if AMRUADTHAW in the cell is set to Yes and the call is an AMR call. On receiving the message, the BTS adaptively adjusts the AMR coding scheme for the call.

When the BSC sends the BTS a channel activation or a speech coding scheme modification message, the channel activation or the speech coding scheme modification message carries DLLTFERUPTH, DLLTFERLOWTH, DLLTFERTGT, and DLLTTHADJFA, if AMRDADTHAW in the cell is set to Yes and the call is an AMR call. On receiving the message, the BTS adaptively adjusts the AMR coding scheme for the call.

3.4 Um Interface Speech Frame Repairing

This feature automatically repairs the bit-error speech frames over the Um interface, thereby minimizing the impact of the bit-error speech frames on speech performance. This feature is implemented by applying an enhanced decoding technique to the Um interface. (GBFD-115708 Um Interface Speech Frame Repairing)

This feature, applicable to only the uplink, repairs speech frames in the source and channel decoding of EFR and three types of AMR: 4.75 kbit/s, 7.40 kbit/s, and 12.2 kbit/s. Therefore, this feature improves the Mean Opinion Score (MOS) by 0.1 to 0.2 when the C/I ratio is low.

To enable the Um Interface Speech Frame Repairing function, set UMSFRSWITCH to ON.

3.5 AMR Power Control

The procedure of power control for AMR calls is similar to that for non-AMR calls. (GBFD-115503 AMR Power Control)

In Huawei II power control algorithm and Huawei III power control algorithm, parameters related to AMR power control are configured separately from those related to non-AMR power control. The AMR calls and non-AMR calls can adopt different power control strategies. For details, see Power Control Feature Parameter Description. The following lists the parameters related to AMR power control.

AMRPCADJPERIOD

AMRULLEVFTLEN

AMRDLLEVFTLEN

AMRULQUAFTLEN

AMRDLQUAFTLEN

AMRMRCOMPREG

AMRULPREDLEND

AMRDLPREDLEND

AMRULSSHTHRED

AMRULSSLTHRED

AMRULQHTHRED

AMRULQLOWTHRED

AMRDLSSHTHRED

AMRDLSSLTHRED

AMRDLQHTHRED

AMRDLQLTHRED

AMRMAXSTEP0

AMRMAXSTEP1

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GSM BSS




3-7

AMRMAXSTEP2

AMRQUALSTEP

AMRMAXVALADJRX

AMRMAXADJPCVAL

AMRULQUALBADTRIG

AMRULQUALBADUPLEV

AMRDLQUALBADTRIG

AMRDLQUALBADUPLEV

AMRBTSPWRNUM

3.6 Handover

The Intra-cell AMR TCHF-TCHH handover algorithm is introduced in both handover algorithm I and handover algorithm II. For details, see the Handover Feature Parameter Description

Through the dynamic conversion between AMR HR channels and AMR FR channels, the speech quality and the system capacity are optimally balanced.

Before implementing the intra-cell AMR TCHF-TCHH handover algorithm, you must enable the half-rate service and AMR HR.

3.7 E-CODER

Enhanced Coding (E-CODER) optimizes AMR coding modules, therefore improving AMR voice quality. The

emulation results show that E-CODER improves the MOS by 0.05 to 0.12.E-CODER is not supported when A over IP and TFO are enabled. E-CODER is supported only in downlink.

To enable the E-CODER function, set EncodeMode to ON.


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GSM BSS

AMR 4 Related Features



4-1

4 Related Features

Table 4-1 Related features

Feature Prerequisite Feature Mutually Exclusive Feature

Affected Feature

AMR FR None None None

AMR HR GBFD-113401 Half Rate Speech

None None

AMR Power Control GBFD-115501 AMR FR

GBFD-115502 AMR HR

None None

AMR Coding Rate Threshold Adaptive Adjustment

GBFD-117501 Enhanced Measurement Report (EMR)

GBFD-115501 AMR FR

GBFD-115502 AMR HR

GBFD-115701 TFO

GBFD-117702 BTS Local Switch

GBFD-117701 BSC Local Switch

GBFD-118602 A over IP

GBFD-118622 A IP over E1/T1

None

Um Interface Speech Frame Repairing

None None None

AMR Radio Link Timer GBFD-115501 AMR FR

GBFD-115502 AMR HR

None None

AMR FR/HR Dynamic Adjustment

GBFD-115501 AMR FR

GBFD-115502 AMR HR

GBFD-110601 HUAWEI I Handover

GBFD-510501 HUAWEI II Handover

None None

GSM BSS

AMR 5 Impact on the Network



5-1

5 Impact on the Network

5.1 AMR FR

5.1.1 Impact on System Capacity

The AMR FR feature provides a strong anti-interference capability to calls. This allows tight frequency reuse and increases system capacity.

With this feature, calls in some weak coverage areas can be maintained. This reduces the possibility of active hang-ups, increasing the traffic volume.

5.1.2 Impact on Network Performance

The voice quality of 12.2 kbit/s AMR FR calls is equivalent to that of EFR calls and is better than that of FR calls. In areas with weak signals, the voice quality of low-rate AMR FR calls is much better than that of EFR and FR calls because of strong robustness of AMR FR calls.

5.2 AMR HR


When network capacity is limited, the AMR HR feature increases system capacity and reduces the network congestion rate while maintaining acceptable voice quality.


The voice quality of 7.4 kbit/s AMR HR calls is better than that of HR calls. In weak coverage areas, the voice quality of low-rate AMR HR calls is much better than that of HR calls because of strong robustness of AMR HR calls.



The AMR Power Control feature improves the anti-interference capability. This allows tight frequency reuse and increases system capacity.


AMR optimizes the speech codec but not the signaling codec. Therefore, AMR slightly affects the handover success rate theoretically. AMR can expand the radio network coverage. Therefore, MSs can make calls even if they are located in weak coverage areas. However, the receive quality in measurement reports (MRs) is poor, leading to bad quality handovers. When AMR is enabled, the number of bad quality handovers may increase. When the AMR Power Control feature is enabled, network interference decreases, and the number of handovers due to interference decreases.

This feature enhances the anti-interference capability for AMR calls, improving voice quality experience of subscribers in weak coverage areas.

5.4 AMR Coding Rate Threshold Adaptive Adjustment


None

GSM BSS

AMR 5 Impact on the Network



5-2


The AMR Coding Rate Threshold Adaptive Adjustment feature makes AMR coding rate adjustment thresholds and hysteresis more adaptive to the Um interface quality, improving the voice quality.



None


In weak coverage areas with low a CIR, the Um Interface Speech Frame Repairing feature reduces the proportion of frame loss due to poor signal quality, improving the voice quality.

5.6 AMR Radio Link Timer


None


AMR FR improves the robustness of AMR FR speech frames but not the robustness of SACCH signaling frames. Therefore, AMR FR does not affect the TCH call drop rate theoretically. In practice, however, when AMR FR is enabled, the TCH call drop rate increases because of the following causes:

For EFR/FR/HR calls, SACCH signaling frames have the similar robustness to that of speech frames. Therefore, a subscriber in a weak coverage area may hang up the phone because of poor conversation quality. Such a hang-up is not counted as a call drop. However, such a hang-up for an AMR call is counted as a call drop.

When AMR FR is enabled, the robustness of AMR FR speech frames is stronger than that of SACCH signaling frames. Therefore, speech frames area can be correctly decoded in a weak coverage, and therefore subscribers will not hang up the phone. SACCH frames, however, cannot be correctly decoded. Therefore, RLT expires, and call drops occur, leading to an increase in the TCH call drop rate.

AMR FR and AMR HR incorporates the following parameters: AFRDSBLCNT, AHRDSBLCNT, AFRSAMULFRM, and AHRSAMULFRM. By modifying the settings of these parameters, you can improve the robustness of SACCH signaling frames and enhance network coverage performance using AMR to decrease the TCH call drop rate.

5.7 AMR FR/HR Dynamic Adjustment


Conversion from AMR FR to AMR HR increases network capacity and decreases network deployment costs while maintaining voice quality.


Conversion from AMR HR to AMR FR improves the Um interface quality when the radio link quality deteriorates. This improves network performance.

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GSM BSS

AMR 6 Engineering Guidelines



6-1

6 Engineering Guidelines

6.1 When to Use AMR

6.1.1 AMR FR and AMR HR

It is recommended that the AMR FR or AMR HR feature be used in the following scenarios:

Capacity-sufficient scenarios: If the number of AMR calls reach a certain proportion, enable AMR FR or AMR HR in some cells to improve voice quality and user experience.

Capacity-limited scenarios: Based on the strong anti-interference capability of AMR, tight frequency reuse can be used. Based on the similarity of voice quality between AMR FR used with AMR HR and AMR FR, some HR channels can be used to improve the network capacity while maintaining network quality.

6.1.2 AMR Power Control

It is recommended that the AMR Power Control feature be used with AMR FR or AMR HR. This enhances anti-interference capability, increases network capacity, and improves voice quality.

6.1.3 AMR Coding Rate Threshold Adaptive Adjustment

It is recommended that the AMR Coding Rate Threshold Adaptive Adjustment feature be used when radio link quality varies frequently or network planning personnel are difficult to predict radio quality. With this feature, the BTS adaptively adjusts AMR coding rate thresholds to ensure AMR performance.

6.1.4 Um Interface Speech Frame Repairing

It is recommended that the Um Interface Speech Frame Repairing feature be used when poor uplink receive quality causes a high uplink Frame Erase Ratio (FER). This feature repairs speech frames, improving uplink voice quality.

6.1.5 AMR Radio Link Timer

It is recommended that the AMR Radio Link Timer feature be used with AMR FR or AMR HR. This decreases the call drop rate and improves user experience.

6.1.6 AMR FR/HR Dynamic Adjustment

It is recommended that the AMR FR/HR Dynamic Adjustment feature be used in a capacity-limited scenario where both AMR FR and AMR HR are used. This helps balance cell capacity and voice quality.

6.2 Information to Be Collected


Before deploying the AMR FR or AMR HR feature, collect the following information: AMR-capable MS penetration rate and Um-interface coverage quality. For AMR HR deployment, you also need to learn about the network load. If the network is congested, you are advised to enable AMR HR.


None

GSM BSS




6-2


Before deploying the AMR Coding Rate Threshold Adaptive Adjustment feature, analyze network interference and determine AMR coding rate adjustment thresholds. This feature supports the functions of uplink and downlink AMR coding rate threshold adaptive adjustment. The downlink AMR coding rate threshold adaptive adjustment function depends on the Enhanced Measurement Report (EMR) feature. Before enabling this function, collect the EMR-capable MS penetration rate.


Before deploying the Um Interface Speech Frame Repairing feature, check whether there are a large number of calls with poor uplink quality.


Before deploying the AMR Radio Link Timer feature, collect the AMR FR or AMR HR call drop rate.


Before deploying the AMR FR/HR Dynamic Adjustment feature, check whether the network is congested and whether AMR HR is enabled.

6.3 Network Planning


RF Planning

According to the impact of AMR on network capacity and quality, RF planning for AMR is as follows: Compared with FR and EFR, AMR supports a lower CIR with the same voice quality. In addition, AMR improves network performance in a tight frequency reuse pattern. Therefore, you can configure some channels on a TRX as AMR HR channels with the same network frequency planning so that these AMR HR channels are allocated to AMR calls. This increases system capacity.

Certain MSs do not support AMR. Therefore, you must appropriately plan the network capacity based on the AMR-capable MS penetration rate and select a proper frequency reuse pattern for frequency planning. If you perform network planning without considering the MSs that do not support AMR, the overall network KPIs deteriorate.

Network Topology

N/A

Hardware Planning

N/A


N/A


N/A

GSM BSS




6-3


N/A


N/A


N/A

6.4 Deploying AMR FR and AMR HR

For details about how to activate, verify, and deactivate this feature, see Configuring AMR.

6.5 Deploying AMR Power Control


6.6 Deploying AMR Coding Rate Threshold Adaptive Adjustment

For details about how to activate, verify, and deactivate this feature, see Configuring AMR Coding Rate Threshold Adaptive Adjustment.

6.7 Deploying Um Interface Speech Frame Repairing

For details about how to activate, verify, and deactivate this feature, see Configuring Um Interface Speech Frame Repairing.

6.8 Deploying AMR Radio Link Timer


6.9 Deploying AMR FR/HR Dynamic Adjustment

For details about how to activate, verify, and deactivate this feature, see Configuring HUAWEI II Handover.

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GSM BSS

AMR 7 Performance Optimization



7-1

7 Performance Optimization

7.1 AMR FR and AMR HR

Monitoring

You can monitor the counters related to channel usage for the AMR FR and AMR HR traffic in a cell to determine whether the network performance needs to be optimized. Table 7-1 lists the related counters.

Table 7-1 Counters related to channel usage for the AMR FR and AMR HR traffic

Counter Description Counter Name

A0409I:Full Rate AMR TCH Successful Call Occupancy Times (Service Channel)

CELL.CALL.OCCUPY.SUCC.TCHF.AMR

A0409J:Full Rate AMR TCH Successful Handover Occupancy Times (Service Channel)

CELL.CALL.HO.OCCUPY.SUCC.TCHF.AMR

AR3551C:Traffic Volume on AMR TCHFs CELL.CHAN.BUSY.NUM.TCHF.AMR.TRAF.AVE

A0409L:Half Rate AMR TCH Successful Call Occupancy Times (Service Channel)

CELL.CALL.OCCUPY.SUCC.TCHH.AMR

A0409M:Half Rate AMR TCH Successful Handover Occupancy Times (Service Channel)

CELL.CALL.HO.OCCUPY.SUCC.TCHH.AMR

AR3552C:Traffic Volume on AMR TCHHs CELL.CHAN.BUSY.NUM.TCHH.AMR.TRAF.AVE

Parameter Optimization

To adjust the AMR FR and AMR HR traffic, run the BSC6900 MML command SET GCELLCHMGAD with TCHBUSYTHRES set to an appropriate value. If this parameter is set to a large value, the AMR FR traffic increases. If this parameter is set to a small value, the AMR HR traffic increases.


N/A

7.3 AMR Coding Rate Threshold Adaptive Adjustment

N/A


N/A

7.5 AMR Radio Link Timer

Monitoring

You can monitor the counters related to AMR FR and AMR HR call drops to determine whether the network performance needs to be optimized. Table 7-2 lists the related counters.

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GSM BSS




7-2

Table 7-2 Counters related to AMR FR and AMR HR call drops

Counter Description Counter Name

M0121A:Full Rate AMR Service Channel Call Drop Times

CELL.CALL.DROP.AMRFR.CAll.FAIL

M0121B:Half Rate AMR Service Channel Call Drop Times

CELL.CALL.DROP.AMRHR.CAll.FAIL

A0409N:Full Rate AMR Call Drop Rate CELL.CALL.DROP.CALL.RATE.TCHF.AMR

A0409P:Half Rate AMR Call Drop Rate CELL.CALL.DROP.CALL.RATE.TCHH.AMR

Parameter Optimization

To adjust the effect of the AMR Radio Link Timer feature, run the BSC6900 MML command SET GCELLCCBASIC with AFRSAMULFRM, AHRSAMULFRM, AFRDSBLCNT, and AHRDSBLCNT set to appropriate values. The larger the value of this parameter, the lower the call drop rate, but the more channel resources are wasted. The smaller the value of this parameter, the fewer channel resources are wasted, but the higher the call drop rate.

7.6 AMR FR/HR Dynamic Adjustment

See the Handover Feature Parameter Description.





Handover.htm

GSM BSS




7-1

GSM BSS

AMR 8 Parameters



8-1

8 Parameters

Table 8-1 Parameter description

Parameter ID

NE MML Command

Feature ID Feature Name

Description

ACTCDSETF

BSC6900 SET GCELLCCAMR(Optional)

GBFD-115501

GBFD-115701

AMR FR

TFO

Meaning: Active coding set (ACS)[F], indicates a set of full-rate coding rates currently available for calls. The AMR is a set of multiple speech coding and decoding rates.If an IP based user plane A-Interface is chosen,5.15KBIT/S will not be included(see 3GPP TS 28.062).

GUI Value Range: 4_75KBIT/S, 5_15KBIT/S, 5_90KBIT/S, 6_70KBIT/S, 7_40KBIT/S, 7_95KBIT/S, 10_2KBIT/S, 12_2KBIT/S

Actual Value Range: 4_75KBIT/S, 5_15KBIT/S, 5_90KBIT/S, 6_70KBIT/S, 7_40KBIT/S, 7_95KBIT/S, 10_2KBIT/S, 12_2KBIT/S

Default Value: 4_75KBIT/S-1&5_15KBIT/S-0&5_90KBIT/S-1&6_70KBIT/S-0&7_40KBIT/S-1&7_95KBIT/S-0&10_2KBIT/S-0&12_2KBIT/S-1

Unit: None

AFRDSBLCNT

BSC6900 SET GCELLCCBASIC(Optional)

GBFD-115505 AMR Wireless Link Timer

Meaning: Counter for radio link failures during an AMR full rate call. See the description of "Radio Link Timeout" in "SET GCELLCCBASIC".

GUI Value Range: 4_Times, 8_Times, 12_Times, 16_Times, 20_Times, 24_Times, 28_Times, 32_Times, 36_Times, 40_Times, 44_Times, 48_Times, 52_Times, 56_Times, 60_Times, 64_Times

Actual Value Range: 1920~30720

Default Value: 64_Times

Unit: 480ms

AFRSAMULFRM



Meaning: Number of SACCH multiframes during an AMR full rate call. See the description of "SACCH Multi-Frames" in "SET GCELLCCBASIC".

GUI Value Range: 0~63


Default Value: 48



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GSM BSS

AMR 8 Parameters



8-2

Parameter ID

NE MML Command


Description

Unit: 480ms

AHRDSBLCNT



Meaning: Counter for radio link failures during an AMR half rate call. See the description of "Radio Link Timeout" in "SET GCELLCCBASIC".




Unit: 480ms

AHRSAMULFRM



Meaning: Number of SACCH multiframes during an AMR half rate call. See the description of "SACCH Multi-Frames" in "SET GCELLCCBASIC".



Default Value: 32

Unit: 480ms

AMRBTSPWRNUM

BSC6900 SET GCELLPWR2(Optional)

GBFD-115503 AMR Power Control

Meaning: Maximum degree by which the BSC can control the power of the AMR BTS dynamically



Default Value: 16

Unit: 2dB

AMRDADTHAW


GBFD-115506 AMR Coding Rate Threshold Adaptive Adjustment

Meaning: Whether to enable the adaptive adjustment function of AMR downlink threshold. After this function is enabled, the BTS estimates the long-term voice quality (indicated by the long-term FER(frame erase ratio)) and compares the estimated result with the specified target voice quality. If the estimated result does not conform to the target voice quality, it indicates that the current AMR handover threshold may not be the best for the current radio conditions. In this case, the BSC6900 adjust threshold adaptively according to the relation between the















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GSM BSS

AMR 8 Parameters



8-3

Parameter ID

NE MML Command


Description

estimated voice quality and the target voice quality.

GUI Value Range: NO(No), YES(Yes)

Actual Value Range: NO, YES

Default Value: NO

Unit: None

AMRDLLEVFTLEN



Meaning: Number of measurement reports sampled for averaging downlink AMR signal strength. A single measurement report may not reflect the actual network situations accurately. Therefore, the BSC needs to average the measured values in several successive measurement reports to reflect the radio environment.


Actual Value Range: TCH:480~9600, step:480; SDCCH:470~9400, step:470

Default Value: 5

Unit: ms

AMRDLPREDLEND



Meaning: Number of downlink AMR measurement reports that the BSC predicts. The BSC takes a while to confirm the power control effect of a power control command. Thus, the BSC makes a power control decision based on a measurement report that lags behind the changes in the receive level and quality instead of reflecting the real-time radio environment. As a result, the power control is late.

To prevent late power control to a certain degree, the power control algorithm involves a measurement report prediction filter. The BSC can sample several downlink measurement reports in a short time and filter them according to a specific weight to predict future N measurement reports.

This parameter specifies the number N.



Default Value: 0

Unit: None

AMRDLQH BSC6900 SET GBFD-115503 AMR Power Meaning: Quality level threshold for











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GSM BSS

AMR 8 Parameters



8-4

Parameter ID

NE MML Command


Description

THRED GCELLPWR2(Optional)

Control decreasing downlink AMR signal power. If the BTS transmits AMR signals at a quality level less than "AMR DL Qual. Upper Threshold", the BSC decreases the power of the BTS. If (downlink receive level - "AMR MAX Down Adj. PC Value by Qual.") < "AMR DL RX_LEV Lower Threshold", the BSC does not adjust the transmit power.



Default Value: 0

Unit: None

AMRDLQLTHRED



Meaning: Quality level threshold for increasing downlink AMR signal power. If the BTS transmits AMR signals at a quality level greater than "AMR DL Qual. Lower Threshold", the BSC increases the power of the BTS. If (downlink receive level + "AMR MAX Up Adj. PC Value by Qual.") > "AMR DL RX_LEV Upper Threshold", the BSC does not adjust the transmit power.



Default Value: 3

Unit: None

AMRDLQUAFTLEN



Meaning: Number of measurement reports sampled for averaging downlink AMR signal quality. A single measurement report may not reflect the actual network situations accurately. Therefore, the BSC needs to average the measured values in several successive measurement reports to reflect the radio environment.



Default Value: 5

Unit: ms

AMRDLQUALBADTRIG



Meaning: During downlink power control, if the downlink receive quality level is equal to or greater than this

















GSM BSS

AMR 8 Parameters



8-5

Parameter ID

NE MML Command


Description

threshold, "AMR DL RX_LEV Upper Threshold" is increased by "AMR DL Qual Bad UpLEVDiff" to further increase the expected downlink power level.



Default Value: 2

Unit: None

AMRDLQUALBADUPLEV



Meaning: During downlink power control, if the downlink receive quality level is equal to or greater than "AMR DL Qual Bad Trig Threshold", "AMR DL RX_LEV Upper Threshold" is increased by "AMR DL Qual Bad UpLEVDiff" to further increase the expected downlink power level.



Default Value: 8

Unit: dB

AMRDLSSHTHRED



Meaning: Upper threshold for downlink AMR signal strength.

If the downlink received AMR signal level is greater than this threshold, a power decrease is computed. Then, the power is decreased by the least of the power decrease, maximum power adjustment step allowed by the quality zone to which the received signal quality belongs, and "AMR MAX Down Adj. PC Value by Qual.".

Power decrease = downlink received signal level - ("AMR DL RX_LEV Upper Threshold" + "AMR DL RX_LEV Lower Threshold")/2

The maximum power adjustment step allowed by the quality zone is chosen from "AMR MAX Down Adj. Value Qual. Zone 0", "AMR MAX Down Adj. Value Qual. Zone 1", and "AMR MAX Down Adj. Value Qual. Zone 2" according to the quality zone.



Default Value: 33












GSM BSS

AMR 8 Parameters



8-6

Parameter ID

NE MML Command


Description

Unit: dB

AMRDLSSLTHRED



Meaning: Lower threshold for downlink AMR signal strength.

If the downlink received AMR signal level is less than this threshold, a power increase is computed. Then, the power is increased by the least of the power increase, "AMR MAX Up Adj. PC Value by RX_LEV", and "AMR MAX Up Adj. PC Value by Qual.".

Power increase = ("AMR DL RX_LEV Upper Threshold" + "AMR DL RX_LEV Lower Threshold")/2 - downlink received signal level.



Default Value: 25

Unit: dB

AMRMAXADJPCVAL



Meaning: Maximum step by which the power can be increased according to received signal quality



Default Value: 8

Unit: dB

AMRMAXSTEP0



Meaning: Maximum step by which the power can be decreased when the received signal quality belongs to quality zone 0.

Huawei power control algorithm generation II classifies the received signal quality into three quality zones. The maximum step by which the power can be decreased according to signal level varies according to the quality zones.



Default Value: 2

Unit: dB

AMRMAXSTEP1
























GSM BSS

AMR 8 Parameters



8-7

Parameter ID

NE MML Command


Description




Default Value: 0

Unit: dB

AMRMAXSTEP2







Default Value: 0

Unit: dB

AMRMAXVALADJRX



Meaning: Maximum step by which the power can be increased according to received signal level



Default Value: 8

Unit: dB

AMRMRCOMPREG



Meaning: Whether to enable the compensation of AMR measurement reports in Huawei power control algorithm generation II

If this parameter is set to YES, Huawei power control algorithm generation II puts a currently received measurement report into the measurement report compensation queue. Then, the algorithm records the change in the transmit power based on the MS/BTS power in the measurement report.
















GSM BSS

AMR 8 Parameters



8-8

Parameter ID

NE MML Command


Description

According to the power change, the algorithm compensates the received signal level in a history measurement report after measurement report interpolation.

Before making a power control decision, the BSC samples and weights the received signal level and quality in several history measurement reports. The MS/BTS transmit power may vary over these measurement reports. To ensure the accuracy of the received signal level and quality to be weighted, the power control algorithm needs to compensate the received signal level and quality in the history measurement reports where the transmit power differs from the current transmit power.



Default Value: YES

Unit: None

AMRPCADJPERIOD



Meaning: Minimum interval between two consecutive AMR power control commands



Default Value: 3

Unit: 480ms

AMRQUALSTEP



Meaning: Maximum step by which the power can be decreased according to received signal quality



Default Value: 4

Unit: dB

AMRUADTHAW



Meaning: Whether to enable the adaptive adjustment function of AMR uplink threshold. After this function is enabled, the BTS estimates the long-term voice quality (indicated by the long-term FER(frame erase ratio)) and compares the estimated result with the specified target voice quality. If the estimated result does not conform to the target voice quality, it indicates that
















GSM BSS

AMR 8 Parameters



8-9

Parameter ID

NE MML Command


Description

the current AMR handover threshold may not be the best for the current radio conditions. In this case, the BSC6900 uses the relevant algorithm to adjust the adaptive threshold according to the relation between the estimated voice quality and the target voice quality.



Default Value: NO

Unit: None

AMRULLEVFTLEN



Meaning: Number of measurement reports sampled for averaging uplink AMR signal strength. A single measurement report may not reflect the actual network situations accurately. Therefore, the BSC needs to average the measured values in several successive measurement reports to reflect the radio environment.



Default Value: 5

Unit: ms

AMRULPREDLEND



Meaning: Number of uplink AMR measurement reports that the BSC predicts. The BSC takes a while to confirm the power control effect of a power control command. Thus, the BSC makes a power control decision based on a measurement report that lags behind the changes in the receive level and quality instead of reflecting the real-time radio environment. As a result, the power control is late.

To prevent late power control to a certain degree, the power control algorithm involves a measurement report prediction filter. The BSC can sample several downlink measurement reports in a short time and then weigh them to predict future N measurement reports.

This parameter specifies the number N.












GSM BSS

AMR 8 Parameters



8-10

Parameter ID

NE MML Command


Description


Default Value: 0

Unit: None

AMRULQHTHRED



Meaning: Quality level threshold for decreasing the power of an uplink AMR call. If the MS transmits AMR signals at a quality level less than "AMR ULQual. Upper Threshold", the BTS decreases the power of the MS. If (uplink receive level - "AMR MAX Down Adj. PC Value by Qual.") < "AMR UL RX_LEV Lower Threshold", the BTS does not adjust the transmit power.



Default Value: 0

Unit: None

AMRULQLOWTHRED



Meaning: Quality level threshold for increasing the power of an uplink AMR call. If the MS transmits AMR signals at a quality level greater than "AMR UL Qual. Lower Threshold", the BTS increases the power of the MS. If (uplink receive level + "AMR MAX Up Adj. PC Value by Qual.") > "AMR UL RX_LEV Upper Threshold", the BTS does not adjust the transmit power.



Default Value: 3

Unit: None

AMRULQUAFTLEN



Meaning: Number of measurement reports sampled for averaging uplink AMR signal quality. A single measurement report may not reflect the actual network situations accurately. Therefore, the BSC needs to average the measured values in several successive measurement reports to reflect the radio environment.



Default Value: 5

Unit: ms
















GSM BSS

AMR 8 Parameters



8-11

Parameter ID

NE MML Command


Description

AMRULQUALBADTRIG



Meaning: During uplink power control, if the uplink receive quality level is equal to or greater than this threshold, "AMR UL RX_LEV Upper Threshold" is increased by "AMR UL Qual. Bad UpLEVDiff" to further increase the expected uplink power level.



Default Value: 3

Unit: None

AMRULQUALBADUPLEV



Meaning: During uplink power control, if the uplink receive quality level is equal to or greater than "AMR UL Qual. Bad Trig Threshold", "AMR UL RX_LEV Upper Threshold" is increased by "AMR UL Qual. Bad UpLEVDiff" to further increase the expected uplink power level.



Default Value: 6

Unit: dB

AMRULSSHTHRED



Meaning: Upper threshold for uplink AMR signal strength

If the uplink received AMR signal level is greater than this threshold, a power decrease is computed. Then, the power is decreased by the least of the power decrease, maximum power adjustment step allowed by the quality zone to which the received signal quality belongs, and "AMR MAX Down Adj. PC Value by Qual.".

Power decrease = uplink received signal level - ("AMR UL RX_LEV Upper Threshold" + "AMR UL RX_LEV Lower Threshold")/2

The maximum power adjustment step allowed by the quality zone is chosen from "AMR MAX Down Adj. Value Qual. Zone 0", "AMR MAX Down Adj. Value Qual. Zone 1", and "AMR MAX Down Adj. Value Qual. Zone 2" according to the quality zone.



















GSM BSS

AMR 8 Parameters



8-12

Parameter ID

NE MML Command


Description


Default Value: 30

Unit: dB

AMRULSSLTHRED



Meaning: Lower threshold for uplink AMR signal strength.

If the uplink received AMR signal level is less than this threshold, a power increase is computed. Then, the power is increased by the least of the power increase, "AMR MAX Up Adj. PC Value by RX_LEV", and "AMR MAX Up Adj. PC Value by Qual.".

Power increase = ("AMR UL RX_LEV Upper Threshold" + "AMR UL RX_LEV Lower Threshold")/2 - uplink received signal level.



Default Value: 18

Unit: dB

DLLTFERLOWTH



Meaning: Lower voice quality threshold associated with the automatic adjustment of the AMR downlink handover threshold. The value of this parameter must be smaller than or equal to the value of Downlink Long-term FER Target.



Default Value: 2

Unit: None

DLLTFERTGT



Meaning: Target value of the voice quality automatically adjusted through the downlink threshold of AMR handover



Default Value: 8

Unit: None

DLLTFERUPTH


GBFD-115506 AMR Coding Rate Threshold Adaptive

Meaning: Upper voice quality threshold associated with the automatic adjustment of the AMR handover downlink threshold.





















GSM BSS

AMR 8 Parameters



8-13

Parameter ID

NE MML Command


Description

Adjustment GUI Value Range: 2~255


Default Value: 60

Unit: None

DLLTTHADJFA



Meaning: Factor of downlink threshold adjustment. It indicates the linear relation between the threshold adjustment value and the logarithmic FER.



Default Value: 40

Unit: None

EncodeMode

BSC6900 SET TCPARA(Optional)

GBFD-115711 EVAD Meaning: Whether to improve the voice quality of AMR and EFR services. If this switch is turned on, the downlink MOS of AMR and EFR services is significantly improved. This parameter is used in A over TDM.

GUI Value Range: STANDARD(Standard code mode), ECODEC(Enhanced code mode)

Actual Value Range: STANDARD, ECODEC

Default Value: STANDARD

Unit: None

LTFERLOWTH



Meaning: Lower voice quality threshold associated with the automatic adjustment of the AMR handover uplink threshold;The value of this parameter must be smaller than or equal to the value of Uplink Long-term FER Target.



Default Value: 2

Unit: None

LTFERTGT BSC6900 SET GCELLCCAMR(Optional)


Meaning: Target voice quality value associated with the automatic adjustment of the uplink threshold of AMR handover



Default Value: 8








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GSM BSS

AMR 8 Parameters



8-14

Parameter ID

NE MML Command


Description

Unit: None

LTFERUPTH



Meaning: Upper voice quality threshold associated with the automatic adjustment of the AMR handover uplink threshold



Default Value: 60

Unit: None

LTTHADJFA



Meaning: Factor of uplink threshold adjustment. It indicates the linear relation between the threshold adjustment value and the logarithmic FER.



Default Value: 40

Unit: None

RATECTRLSW


GBFD-115506

GBFD-115507

AMR Coding Rate Threshold Adaptive Adjustment

WB AMR

Meaning: Switch for controlling the AMR rate. Value ALG1 indicates that C/I is used to control the AMR rate. Value ALG2 indicates that BER is used to control the AMR rate.

GUI Value Range: ALG1(Algorithm I), ALG2(Algorithm II), NONE(None)

Actual Value Range: ALG1, ALG2, NONE

Default Value: ALG1

Unit: None

RLT BSC6900 SET GCELLCCBASIC(Optional)

GBFD-111004 Radio Dedicated Channel Management

Meaning: Time for disconnecting a call when the MS fails to decode the SACCH. Once a dedicated channel is assigned to the MS, the counter S is enabled and the initial value is set to this parameter value.

Each time an SACCH message is not decoded, the counter S decreases by 1. Each time an SACCH message is correctly decoded, the counter S increases by 2. When the counter S is equal to 0, the downlink radio link is considered as failed. Therefore, when the voice or data quality is degraded to an unacceptable situation and it cannot be improved through power control or
















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GSM BSS

AMR 8 Parameters



8-15

Parameter ID

NE MML Command


Description

channel handover, the connection is to be re-established or released.




Unit: 480ms

SERVICEMODE

BSC6900 ADD BTS(Optional)

MOD BTS(Optional)

GBFD-118601 Abis over IP

Meaning: Service type of the BTS.

TDM:Time Division Multiplex Mode;

HDLC:High level Data Link Control Mode;

HDLC_HubBTS:Hub Base Transceiver Station Mode. This value is available for versions earlier than current version only. It is retained here for compatibility concerns only;

IP:Internet Protocol Mode.

GUI Value Range: TDM, HDLC, HDLC_HubBTS, IP

Actual Value Range: TDM, HDLC, HubBTS, IP

Default Value: TDM

Unit: None

TCHBUSYTHRES

BSC6900 SET GCELLCHMGAD(Optional)

GBFD-111005 Enhanced Channel Assignment Algorithm

Meaning: If the current channel seizure ratio reaches or exceeds this value, the half-rate TCH is assigned preferentially; otherwise, the full-rate TCH is assigned preferentially.



Default Value: 60

Unit: %

ULHYSTF1 BSC6900 SET GCELLCCAMR(Optional)

GBFD-115501 AMR FR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB;



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GSM BSS

AMR 8 Parameters



8-16

Parameter ID

NE MML Command


Description

if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.


Actual Value Range: 0~7.5

Default Value: 2

Unit: 0.5dB


GBFD-115501 AMR FR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 3

Unit: 0.5dB


GBFD-115501 AMR FR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 3









GSM BSS

AMR 8 Parameters



8-17

Parameter ID

NE MML Command


Description

Unit: 0.5dB

ULHYSTH1 BSC6900 SET GCELLCCAMR(Optional)

GBFD-115502 AMR HR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 3

Unit: 0.5dB





Default Value: 4

Unit: 0.5dB


GBFD-115502 AMR HR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the













GSM BSS

AMR 8 Parameters



8-18

Parameter ID

NE MML Command


Description

call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 15

Unit: 0.5dB

ULTHF1 BSC6900 SET GCELLCCAMR(Optional)

GBFD-115501

GBFD-115507

AMR FR

WB AMR

Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 15

Unit: 0.5dB


GBFD-115501

GBFD-115507

AMR FR

WB AMR












GSM BSS

AMR 8 Parameters



8-19

Parameter ID

NE MML Command


Description

Default Value: 19

Unit: 0.5dB


GBFD-115501

GBFD-115507

AMR FR

WB AMR




Default Value: 28

Unit: 0.5dB

ULTHH1 BSC6900 SET GCELLCCAMR(Optional)




Default Value: 23

Unit: 0.5dB


GBFD-115502 AMR HR Meaning: Based on the RQI in the call measurement report, the BTS and MS automatically adjust the current speech coding rate according to the related algorithm. The coding rate adjustment threshold is the threshold of RQI. The RQI indicates the













GSM BSS

AMR 8 Parameters



8-20

Parameter ID

NE MML Command


Description

carrier-to-interference ratio (CIR) of the call. If RQI equals 1, the CIR is 0.5 dB; if RQI equals 2, the CIR is 1 dB; and so forth. Since there are multiple coding rates in the ACS, there is an adjustment threshold and an adjustment hysteresis between the neighboring coding rates.



Default Value: 31

Unit: 0.5dB





Default Value: 63

Unit: 0.5dB

UMSFRSWITCH


GBFD-115708 Um Interface Speech Frame Repairing

Meaning: Switch for Um interface speech frame repair. When this parameter is set to ON, Um interface speech frame repair is enabled. When this parameter is set to OFF, Um interface speech frame repair is disabled.



Default Value: NO

Unit: None











GSM BSS

AMR 9 Counters



9-1

9 Counters

Table 9-1 Counter description

Counter ID Counter Name Counter Description Feature ID Feature Name

1278076514 CELL.ASS.CMP.SPEECH.VER.3.DIRECT.RETRY.DR.TCHF

A3111A:Cell Assignment Complete Times of Speech Version 3 (Direct Retry) (TCHF)

GBFD-115501 AMR FR

1278076515 CELL.ASS.CMP.SPEECH.VER.3.DIRECT.RETRY.DR.TCHH

A3112A:Cell Assignment Complete Times of Speech Version 3 (Direct Retry) (TCHH)

GBFD-115502 AMR HR

1278077528 CELL.INTRACELL.HO.DETECT.SPEECH.VER.3.TCHF

H3099X:BSC Intra-cell Handover Detection Times (AMR) (TCHF)

GBFD-115501 AMR FR

1278077529 CELL.INTRACELL.HO.DETECT.SPEECH.VER.3.TCHH

H3099Y:BSC Intra-cell Handover Detection Times (AMR) (TCHH)

GBFD-115502 AMR HR

1278080483 CELL.BSCTOBSC.INTO.CELL.HO.DETECT.SPEECH.VER.3.TCHF

H3881A:Incoming External Inter-Cell Handover Detection Messages Received by BSC (AMR) (TCHF)

GBFD-115501 AMR FR

1278080484 CELL.BSCTOBSC.INTO.CELL.HO.DETECT.SPEECH.VER.3.TCHH

H3882A:Incoming External Inter-Cell Handover Detection Messages Received by BSC (AMR) (TCHH)

GBFD-115502 AMR HR

1278095417 CELL.CALL.DROP.AMRFR.CAll.FAIL

M0121A:Full Rate AMR Service Channel Call Drop Times

GBFD-115501 AMR FR

1278095418 CELL.CALL.DROP.AMRHR.CAll.FAIL

M0121B:Half Rate AMR Service Channel Call Drop Times

GBFD-115502 AMR HR

1278095421 CELL.CALL.SPEECH.VER.3.REQ.TCHF

A0401C:Supports Call Times of Full Rate Speech Version 3

GBFD-110501

GBFD-115501

Call Control

AMR FR

1278095424 CELL.CALL.SPEECH.VER.3.REQ.TCHH

A0402C:Supports Call Times of Half Rate Speech Version 3

GBFD-115502 AMR HR

1278095433 CELL.CALL.OCCUPY.SUCC.TCHF.AMR

A0409I:Full Rate AMR TCH Successful Call Occupancy Times (Service Channel)

GBFD-115501 AMR FR

1278095434 CELL.CALL.HO.OCCUPY.SUCC.TCHF.AMR

A0409J:Full Rate AMR TCH Successful Handover Occupancy Times (Service Channel)

GBFD-115501 AMR FR

1278095436 CELL.CALL.OCCUPY.SUCC.TCHH.AMR

A0409L:Half Rate AMR TCH Successful Call Occupancy Times (Service Channel)

GBFD-115502 AMR HR

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GSM BSS

AMR 9 Counters



9-2

Counter ID Counter Name Counter Description Feature ID Feature Name

1278095437 CELL.CALL.HO.OCCUPY.SUCC.TCHH.AMR

A0409M:Half Rate AMR TCH Successful Handover Occupancy Times (Service Channel)

GBFD-115502 AMR HR

1278095438 CELL.CALL.DROP.CALL.RATE.TCHF.AMR

A0409N:Full Rate AMR Call Drop Rate

GBFD-115501 AMR FR

1278095439 CELL.CALL.DROP.CALL.RATE.TCHH.AMR

A0409P:Half Rate AMR Call Drop Rate

GBFD-115502 AMR HR

1278271449 CELL.AMR.MS.PWR.LEV.AVE

AS3240A:Average MS Power Level of AMR Call

GBFD-115502

GBFD-115501

GBFD-115503

AMR HR

AMR FR

AMR Power Control

1278271450 CELL.AMR.BTS.PWR.LEV.AVE

AS3241A:Average BTS Power Level of AMR Call

GBFD-115502

GBFD-115501

GBFD-115503

AMR HR

AMR FR

AMR Power Control

1278473476 CELL.CHAN.BUSY.NUM.TCHF.AMR.TRAF.AVE

AR3551C:Traffic Volume on AMR TCHFs

GBFD-115501 AMR FR

1278473477 CELL.CHAN.BUSY.NUM.TCHH.AMR.TRAF.AVE

AR3552C:Traffic Volume on AMR TCHHs

GBFD-115502 AMR HR

1282423819 CELL.CHAN.BUSY.NUM.TCHF.AMR.TRAF.OVERLAY.AVE

AR3559C:Traffic Volume on AMR TCHFs (Overlaid Subcell)

GBFD-115501

GBFD-113201

AMR FR

Concentric Cell

1282423822 CELL.CHAN.BUSY.NUM.TCHH.AMR.TRAF.OVERLAY.AVE

AR3560C:Traffic Volume on AMR TCHHs (Overlaid Subcell)

GBFD-115502

GBFD-113201

AMR HR

Concentric Cell










GSM BSS

AMR 10 Glossary



10-1

10 Glossary

For the acronyms, abbreviations, terms, and definitions, see the Glossary.

Glossary.htm

GSM BSS

AMR 11 Reference Documents



11-1

11 Reference Documents

[1] GSM 05.03: "Digital cellular telecommunications system (Phase 2+); Channel coding"

[2] GSM 05.09: "Digital cellular telecommunications system (Phase 2+); Link Adaptation"

[3] GSM 04.08: "Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3 specification"

[4] GSM 06.90: "Digital cellular telecommunications system (Phase 2+); Adaptive Multi-Rate (AMR) speech transcoding "

[5] GSM 06.91: "Digital cellular telecommunications system (Phase 2+); Substitution and muting of lost frames for Adaptive Multi Rate (AMR) speech traffic channels "

[6] GSM 06.92: "Digital cellular telecommunications system (Phase 2+); Comfort noise aspects for Adaptive Multi-Rate (AMR) speech traffic channels "

[7] GSM 06.93: "Digital cellular telecommunications system (Phase 2+); Discontinuous transmission (DTX) for Adaptive Multi Rate (AMR) speech traffic channels "

[8] GSM 06.94: "Digital cellular telecommunications system (Phase 2+); Voice Activity Detection (VAD) for Adaptive Multi-Rate speech traffic channels "

[9] GSM 08.08: "Digital cellular telecommunications system (Phase 2+); Mobile-services Switching Centre - Base Station System (MSC - BSS) interface; Layer 3 specification "

[10] GSM 08.58: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface; Layer 3 specification "

[11] GSM 08.60: "Digital cellular telecommunications system (Phase 2+); In-band control of remote transcoders and rate adaptors for full rate traffic channels "

[12] GSM 08.61: "Digital cellular telecommunications system (Phase 2+); In band control of remote transcoders and rate adaptors for half rate traffic channels "

[13] BSC6900 Feature List

[14] BSC6900 Optional Feature Description

[15] BSC6900 GSM Parameter Reference

[16] BSC6900 GSM MML Command Reference

[17] BSC6900 GSM Performance Counter Reference

[18] Power Control Feature Parameter Description

[19] Handover Feature Parameter Description

Power%20Control.htm

Handover.htm