amr codec sets

Feature Trial: AMR

Codec Sets

of 8 Mobily Nokia Optimisation Team 15-Aug-07

Objective

To test:

a) availability of the AMR codec sets feature

b) intersystem handover & interRNC handover

c) coverage improvement

Parameters:

Parameter name Configured CS AMR mode sets

Abbreviated name CSAMRModeSET

3GPP name -

Managed object RNC

Parameter group ACConfiguration

Category Radio Resource Utilisation

Multiplicity 1

Description

The parameter defines the AMR mode sets used in UTRAN for the CS AMR call.

The serving RNC allocates the largest set of the configured AMR mode sets, which

are the permitted subsets of the AMR mode set received from the MSC server in the

resource request message. The configured AMR mode set is a permitted subset if

its modes are producing the lowest AMR mode data rates of the resource request

or, if the previous kind of set does not exist, if it has the AMR mode of the highest

data rate. In the latter case, only version 1 of the Iu UP support mode for predefined

SDU sizes is applicable. Equal maximum permitted configured AMR mode sets are

used in the UL and DL transfer directions.

The parameter is applied in SRNC when the resource request is for RAB

assignment request and in the target RNC of relocation hard handover. The

parameter is not significant if the resource request is received in DRNC from Iur;

AMR mode set of the resource request will be used in the establishment of the radio

link. The parameter is not significant in the SRNS relocation, in which UE is not

involved; the target RNC will use the AMR modes received earlier in the resource

requests from Iur.

Value 0'OFF'of the parameter means that the configured AMR mode sets are not

employed; single AMR mode 12.2 kbps set is used as the only AMR mode set.

Range and step Bit 0: CS AMR codec set (12.2), Bit 1: CS AMR codec set (12.2, 7.95, 5.9, 4.75), Bit

2: CS AMR codec set (5.9, 4.75)

Formula for getting

internal value -

Default value 0

Default value notes 'OFF', set of the single AMR mode 12.2 kbps is used.

Feature Trial: AMR

Codec Sets


Related functions Admission Control

Modification On-Line

Related parameters -

Parameter

relationships -

Related features • AMR Codec Sets (12.2, 7.95, 5.90, 4.75) and (5.90, 4.75) (optional)

Interfaces

• RAC <-> RNC

• EM <-> RNC

• RAC <-> RACApp

References • 3GPP Reference: TS 34.108

Location in GUI RNC RNW Object Browser/RNC-dialog/AC-tab

Test 1: Availability of the AMR Codec Sets Feature

PERIOD_START_TIME DUR_FOR_AMR_5_9_DL_IN_SRNC (s) DUR_FOR_AMR_12_2_DL_IN_SRNC (s) 01-Aug-07 0 8867795415 02-Aug-07 0 8692805063 03-Aug-07 0 7833362547 04-Aug-07 0 8920946908 05-Aug-07 0 9208943040 06-Aug-07 0 8645626610 07-Aug-07 8963316 8921971140 08-Aug-07 54585758 9511140589 09-Aug-07 0 8909014331 10-Aug-07 0 8367368542 11-Aug-07 183497226 8249749817 12-Aug-07 51080590 8405890762 13-Aug-07 146900476 8698819151 14-Aug-07 138757913 8745127347 The PLMN table shows that AMR codec is working when the feature is turn on (7Aug).

Feature Trial: AMR

Codec Sets


Test 2: Intersystem & InterRNC handover

Successful tests are done for intersystem and interRNC handovers.

Intersystem Handover

a) 12.2 codec to GSM

b) 5.9 codec to GSM

InterRNC Handover

a) RNC11 12.2 codec to RNC12 12.2 codec and vice versa

b) RNC11 5.9 codec to RNC12 5.9 codec and vice versa

c) RNC11 12.2 codec to RNC12 5.9 codec and vice versa

Inter-RNC cell Statistics

SHO Succ Rate

90

91

92

93

94

95

96

97

98

99

100

1-Aug 2-Aug 3-Aug 4-Aug 5-Aug 6-Aug 7-Aug 8-Aug 9-Aug 10-Aug 11-Aug 12-Aug 13-Aug 14-Aug

U13749_RNC12 U13778_RNC11 AMR Codec

AM

R C

od

ec S

ets

tu

rn o

n

MGW M181 was down from

9pm (11Aug) until 4am

(12Aug)

There is no degradation for SHO success rate after AMR Codec is turned on.

Feature Trial: AMR

Codec Sets


Daily Voice Drop Call

0

1

2

3

4

5

6

7


U13749_RNC12 U13778_RNC11 AMR Codec

AM

R C

od

ec

Se

ts t

urn

on

There is no degradation on voice drop after AMR Codec is turned on

Test 3: Coverage Improvement

The coverage test is done in U1290C. Tester locked the phone in 3G mode and drive

away from U1290C until the voice call is drop.

Figure 1: AMR codec {12.2 only} with 7.66km

Feature Trial: AMR

Codec Sets


Figure 2: AMR codec {12.2, 7.95, 5.9, 4.75} with 9.31km

Figure 3: AMR Codec {5.9, 4.75} with 12.98km

Feature Trial: AMR

Codec Sets


PLMN Statistics

PLMN CSSR_VOICE%

93

94

95

96

97

98

99

100


CSSR_VOICE% AMR Codec

AM

R C

od

ec

Se

ts t

urn

on


9pm (11Aug) until 4am (12Aug)

There is no degradation on CSSR voice after AMR Codec is turned on

PLMN DROP_VOICE%

0

0.1

0.2

0.3

0.4

0.5


DROP_VOICE% AMR Codec

AM

R C

od

ec

Se

ts t

urn

on

There is no degradation on voice drop rate after AMR Codec is turned on

Feature Trial: AMR

Codec Sets


PLMN CS_VOICE_TRAFFIC(ERL)

18000

20500

23000

25500

28000


CS_VOICE_TRAFFIC(ERL) AMR Codec

AM

R C

od

ec

Se

ts t

urn

on

There is no significant decrease in voice traffic

PLMN SHO_SUCC%

99

99.2

99.4

99.6

99.8

100


SHO_SUCC% AMR Codec

AM

R C

od

ec

Se

ts t

urn

on



SHO success rate remains excellent at above 99.8%

Feature Trial: AMR

Codec Sets


PLMN RT_ISHO_SUCC%

85

90

95

100


RT_ISHO_SUCC% AMR Codec

AM

R C

od

ec S

ets

tu

rn o

n



RT ISHO remains excellent at above 98.4%

Benefits

There is coverage improvement when the AMR codec is turned on. When the codec is

decreased, the required power to sustain the call is decreased as well.

By configuring the AMR mode set {5.9} instead of {12.2}, the number of speech users

in the RAN can be increased. This can be perceived in air interface in uplink, Iub/Iur

transmission and code space.

From user point of view, the voice quality remains similar before and after the AMR

codec sets turn on.

Ramadan benefits: Setting the AMR to lower codec {5.9}, Mobily network will be

ready for sudden surge in traffic by having more capacity in terms of spreading code

space and Iub/Iur transmission.

amr codec sets

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