UMTS Speech Quality Principles

Security Level:

UMTS Speech Quality Principles + Troubleshooting Methods + Cases + Deliverables Prepared by: UMTS Maintenance Department/UMTS Design Department Reviewed by: Qi Haofeng

August 29, 2012

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Abstract Speech quality problems are classified into the following two types: •Problems that are measured by using the Mean Opinion Score (MOS). This type of problems generally has a low MOS. •Problems that are measured through end users’ subjective perception of speech quality, including one-way audio, silence, water running sound, and call drop. This presentation describes the 11 prescribed actions and related cases for handling MOS problems as well as six prescribed actions and related cases for handling perceptual speech quality problems. This presentation also offers deliverables that frontline engineers need to submit when feeding back the preceding two types of speech quality problems, including analysis results of alarms, traffic measurement, call history record (CHR), and drive test data. The typical cases in this presentation showcase the importance and necessity for frontline engineers to execute prescribed actions as well as the immediate effect of these actions. If the speech quality problem persists after you execute the 11 prescribed actions for MOS problems and the six prescribed actions (there is an entry criteria for each action) for perceptual speech quality problems, submit this problem to R&D engineers directly.

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Change History Date

Version

2012-8-28

1.0

2012-10-26

1.01

Description

Reviewer

Author

Qi Haofeng, Tang Yuanxian, Gong Qian Lanying, The draft was completed. Jie, Cui Chengxiao, Fan Jingchang, and Fan and Yuan Qiang Jingchang Revised based on review Qian Lanying comments.

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Contents 1

MOS Evaluation Standards and Principle

2

Factors That Affect MOS and MOS Problem Handling Process and Cases

3

Perceptual Speech Quality Problems

 Silence and Noise Handling Process and Cases  Water Running Sound Handling Process and Cases

4

Appendix: Speech Quality Deliverables

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MOS Evaluation Standards and Principle Subjective Evaluation The MOS (scaling 1 to 5) (ITU-T P800) is generated by averaging the results of a set of subjective tests Objective Evaluation The objective evaluation standards obtain the speech quality score by comparing the transmitted degraded signals with the reference signals and adopting an algorithm. These standards include the perceptual analysis measurement system (PAMS) (ITU-T P861), perceptual evaluation of speech quality (PESQ) (P862), PESQ-LQ, and PESQ-LQO(ITU-T P862.1). Parameter Evaluation The transmitted voice signals are estimated through some parameters of the wireless network, for example, the Speech Quality Indicator (SPI) of Ericsson and the Voice Quality Indicator (VQI) of Huawei. This method has a broad prospect for application on wireless networks. Universal rating and acceptance standard

Nowadays carriers around the world use the MOS as a major network acceptance indicator. One of the widely used rating standards is the PESQ-LQO (ITU-T P862.1) algorithm PESQ-LQO scores lie between 1.0 and 4.5 and have five scales: Excellent, Good, Fair, Poor and Bad.

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Speech Quality Testers •

•

Third-party testers: 

DSLA



Swissqual



Comarco



Rising/Dingli

Testers from equipment vendors: 

Ericsson: Tems



Huawei: Probe



Nokia: Nemo

Carriers at present have high requirements for the speech quality test. Mainstream carriers in Europe have used Swissqual as the drive test tool and opted for the PESQLQO(P862.1) standard in the speech quality acceptance test of several offices. HUAWEI TECHNOLOGIES CO., LTD.

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Contents 1

MOS Evaluation Standards and Principle

2

Factors That Affect MOS and MOS Problem Handling Process and Cases

3

Perceptual Speech Quality Problems

Silence and Noise Handling Process and Cases Water Running Sound Handling Process and Cases

4

Appendix: Speech Quality Deliverables

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Factors That Affect MOS 

Factors that affect the MOS include:

1. Test methods, PSTN, and tools (software and hardware), for example, reference signal and software settings. 2. Network-related factors:





Codecs



Bit errors (coverage, interference, transmission, algorithm and equipment)



Handover

To optimize MOS, you need to adopt appropriate test methods, select the optimal codec, and minimize the impact of bit error rate (BER) and handover on the speech quality. In some scenarios, however, optimizing speech quality (for example, link reestablishment and timer optimization) may affect such counters as call drop rate and hard handover success rate.

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Factors That Affect MOS ─ Data Analysis and Statistics of Live Network China Unicom live network has a low MOS. After analysis, you find that the low MOS is caused by: 1. Test method and tool problems. 2. BER problems:     

Coverage Interference Transmission Algorithm Equipment

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Time Point for Problem Analysis

Cause

Number of Problems

May 23

Coverage

2

June 1

Coverage

1

June 4

Equipment problem

5

June 5

Equipment problem

1

June 7

Equipment problem

1

June 7

Test method and tool

1

June 10

Transmission

1

June 10

Coverage

1

June 10

Test method and tool

1

June 11

Interference

2

June 12

Algorithm

1

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MOS Problem Evaluation Method •

Drive test results are used to estimate the MOS.

•

The MOS baseline value of Huawei is 3.6.

•

The following table lists the benchmark data of all VXX offices. If the drive test result is lower than 3.6, the speech quality problem needs to be located. Projects Benchmark

Average MOS

Project1

3.6

Project2

3.9

Project2

3.9

Project3

3.7

Project4

3.9

Project5

3.9

Project6

3.8

Project7

3.9

Project8

3.9

Project9

3.9

Project10

3.9

Project11

3.9

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MOS Problem Handling - Prescribed Action Checklist Step Step 1

Step 2

Step 3

Step 4

Step 5

Prescribed Action

Entry Condition

Purpose of Analysis

Action 1 Check MOS drive test specifications

Unconditional

Check the drive test method and conduct preliminary analysis.

Action 2 Check version known problems on equipments

Unconditional

Check the version and equipment for known problems.

Action 3 Check all parameters

The MOS is smaller than the baseline value or benchmark.

Check whether there are known problems that affect parameter configuration.

Action 4 Analyze characteristics of low The MOS is smaller than 3 MOS

Analyze low MOS distribution and characteristics. (special site, route..)

Action 5 Check encoding/decoding problems

The MOS is smaller than 3.6 and the maximum MOS is lower than 4.0.

Check speech encoding/decoding.

Action 6 Check BER-related coverage

The MOS is smaller than 3.6 and the average BLER is higher than 1%. A linear relationship exists Check the BER-related coverage problem. between MOS and BLER.

Action 7 Check BER-related interference

The MOS is smaller than 3.6 and the average BLER is higher than 1%. A linear relationship exists Check the interference problem. between MOS and BLER.

Action 8 Check BER-related transmission

The MOS is smaller than 3.6 and the average BLER is higher than 1%. A linear relationship exists Check transmission. between MOS and BLER.

Action 9 Check BER-related algorithm

The MOS is smaller than 3.6 and the average BLER Check the impact of other algorithms and is higher than 1%. A linear relationship exists functions on MOS. between MOS and BLER.

Action 10 Check BER-related equipment

The MOS is smaller than 3.6 and the average BLER Check whether the problem is relevant to is higher than 1%. A linear relationship exists board load and faults. between MOS and BLER.

Action 11 Analyze handovers

The hard handover success rate is higher than 35%.

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Check inter-frequency and inter-RAT hard handovers.

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MOS Test Process 

MOS acceptance standards include the following two types: 

MOS acceptance: The MOS of the whole network must reach a given value. For example, MOS must be higher than 3.6.



MOS distribution acceptance: Ex. MOS must be higher than 3.8 and the proportion of MOSs lower than 3 must be less than 1%

•

Record and output the MOS DT Checklist.

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Prescribed Action 1 for Handling MOS Problems Check MOS Drive Test Specifications Drive test specifications: To ensure the effectiveness of drive test data, the drive test must be conducted in strict compliance with the drive test specifications. When carrying out drive test, check all test items against the MOS DT Checklist:  Test instrument and voice sample: Different voice samples have varied MOSs. Select the appropriate voice samples based on the test instruments.  PSTN: Identical core network (CN). Different CNs baseline configurations have a huge impact on the MOS distribution. CN and RAN should use the same configuration  Traffic model: Identical (daytime or nighttime) time segments (avoid holidays or other special dates).  Vehicles and terminals: Identical vehicles and terminals, the same testing engineers, and identical terminal connection and placement modes.  Test routes: Identical test routes (Prepare a GPS map and carry out drive test on the scheduled route) and driving directions.  Test vehicle speed: Identical and stable vehicle speed (Select appropriate time and vehicle speed).  Tool settings: Identical tool settings and statistics collection methods for front-end data collection and rear-end data output.  Statistical methods used by tool: Check such data as the number of samples and handovers, coverage, and MOS distribution after test. If any discrepancy is found, carry out the drive test again. 



Conform to the preceding drive test specifications and check the test items against the MOS DT Checklist.

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Prescribed Action 2 for Handling MOS Problems Check Equipment and Version for Known Problems Check the equipment and version for known problems: •

NodeB version discrepancies

•

The MOS speech quality problems that exist on the WBBP D board are solved in the following versions: 

R12 V200R012C00SPC440



R13 V200R013C00SPC310

WBBP Board: process board for coding and decoding

Use of the WBBP D board in earlier versions may lead to silence, noise and low MOS.

Output known problem check results of equipment and version

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Prescribed Action 3 for Handling MOS Problems - Check All Parameters •

Check all parameters: 

The speech quality parameters that may affect the MOS include TRFO (Trans-coder Free Operation) , AMRC (Adaptive Multi-Rate Control algorithm ), dynamic power control, link reestablishment and water running sound. NPMater , FMA, OMStar..

•

Output parameter check results (weekly task):

MML command SET UCorrmalgoswitch

Parameter ID

Bitmap

Parameter Name

Baseline Value

Impact

CsSwitch

CS_IUUP_V2_SUPPORT_SWITCH

WRFD-011600 TFO/TrFO.

1 (ENABLE)

Enabling this switch will increase MOS by 0.2 without negative impact. (prevent speech quality deterioration)

CS_AMRC_SWITCH

AMRC

0

Enabling this switch will lead to silence or call drop as a result of the UE compatibility issue. Can involve UE Compatibility issue EX: IPhone 4

CMP_UU_AMR_DRD_HHO_COMPA T_SWITCH

DRD HHO CMP Switch

1

This parameter specifies to enable both HHO and DRD to avoid the water running sound caused by UE compatibility issue.

Automatic Noise Correction Switch (R13)

off

The water running sound is automatically corrected. Can involve UE Compatibility => Disable it

CS Link Reestablishment Switch

0

Enabling this switch helps decrease the call drop rate, but will lead to a 6-second silence, compromising user experience.

SRB OVER H Switch

None

The SRB OVER H switch will reduce to the water running sound.

Silence Detect

0

Enable if Mos is bad for Silence is detected.

Dynamic Power Control

1

When cell load is light, turning on this switch enables a low target BLER to be configured for UEs processing voice services. This improves user experience but increases load and shrinks cell coverage, increases the call drop rate of UEs at the cell edge

CmpSwitch

SET UDPUCFGDATA AmrNoiseCorrectSwitch SET URRCTRLSWITCH

RsvdPara1=RSVDBIT1_BIT24

SET UFRCCHLTYPEPAR A

SrbChlType

SET URRCTRLSWITCH

RsvdPara1

SET UCORRMPARA

RSVDBIT1_BIT15

RESERVED_SWITCH_0_BIT24

SET UUEA

EncryptionAlgo

RNC Supported Encryption Algorithm

UEA01&UEA1-1

SET USTATETIMER

HoPhychRecfgTmr

HHO Physical Channel Reconfiguration Timer

5000

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This algorithm must be consistent with that used on the CN. Otherwise, call drop may occur. If this time is set to more than 10000, the water running problem may occur.

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Prescribed Action 4 for Handling MOS Problems Analyze Characteristics of low MOS •

Check distribution of low MOS 

•

If low MOS occurs continuously or massively on one side during a drive test, the problem usually lies with the MOS tester, audio cable connection or test method.

Analyze low MOS: Analyze the drive test UE log. Check and filter out low MOSs values and check the radio quality:



 

If the RSCP < -105 dBm or Ec/Io < -14 dB: => the low MOS is caused by poor quality of radio signals and weak coverage, wireless network optimization is required. If the RTWP > -90 dBm, the low MOS is caused by interference. If the signal quality is good , RSCP < -95 dBm or their Ec/Io < -12 dB, the problem may lie with products.

• Output characteristics analysis result of low MOS:

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Prescribed Action 5 for Handling MOS Problems Check Coding/Decoding Problems MOS mean Score

3.460

Mos Max

3.80

MOS 1% by checking the counter Uu_TrCh_Bler >1%.

DT Information MOS mean Score Average BLER BLER (1) rate(0%-0.78%) BLER (2) rate(0.78%-1.56%) BLER (3) rate(1.56%-3.12%) BLER (4) rate(3.12%-6.24%) BLER (5) rate(6.24%-12.48%) BLER (6) rate(12.48%-100%) AverageRSCP Average Ec/Io Ec/Io 1%. 2. Equipment: •

Equipment alarm analysis

•

Single-UE CDT analysis: FP layer, and statistics of IUUP voice packet errors and transmitted and received frames.

• Output BER-related equipment check result

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Prescribed Action 11 for Handling MOS Problems Analyze Handover Typical characteristics of handover problems: HHO Rate= HHO/MOS sample We analyze the impact of hard handover on MOS through the proportion of the number of hard handovers (HHOs) to the number of MOS calls.

MOS mean Score MOS samples HHO numbers HHO/ MOS sample rate

HHO analysis 

Data source: Traffic measurement, script, and CDT



Analysis tool: Nastar, UltraEdit, and UMAT/FMA



Judgment criteria: 

(Inter-frequency or inter-RAT) HHO may lead to loss of voice frames, which will affect the MOS. Therefore, the HHO rate during conversation needs to be calculated. The smaller the HHR rate, the larger the MOS.



Generally the HHO rate is lower than 30%. The HHO rate of higher than 35% is abnormal, and in that case, you need to check whether the settings of neighboring cells and handover parameters are appropriate.



Output handover check result

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3.46 2135 838 39.25%

MOS Problem Handling Report Develop an analysis report template that contains the problem handling process and all factors that may affect speech quality to thoroughly analyze MOS problems and inform relevant frontline Engineers.

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Typical Case 1 - Test Tool Problem Background: The rate of low MOSs (less than 3) in the drive test of an office is up to 6.19%. Action 1: According to the data feedback checklist, recording files with size below 126 KB are found. The size of a normal recording file should be 126 KB. The MOS of abnormal recording files is less than 3. Root cause: Low MOSs are caused by exceptions of terminals or test tools, which is confirmed by the tool vendor.

MOS mean Score

3.71

Mos Max

4.08

MOS Iub analysis A speech packet is sent at a transmission time interval (TTI) of 20 ms based on UMTS speech features. Check the FP layer according to uplink FP packet statistics, and isolate the NodeB and Iub transmission. Judgment criteria: If any uplink FP packet is lost or all packet are empty, one-way audio problem is related to the Iub interface transmission, RAN process, UEs or NodeB equipment.

The cumulative number of uplink speech packets on the Iub interface does not increase in 8s.

 One-way audio -> Iu analysis A speech packet is sent at a TTI of 20 ms based on UMTS speech features. Check the Iu layer according to uplink and downlink IUUP packet statistics, and isolate the CN and Iu transmission. Judgment criteria: If any downlink FP packet is lost, one-way audio is related to the Iu interface transmission or CN.

The cumulative number of downlink speech packets on the Iu interface does not increase in 10s.

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 One-way audio -> process analysis Analyze the problem to identify whether it is caused by process exceptions. Judgment criteria: If any uplink FP packet is lost at the time point when a complaint is lodged, check whether during this period: •

The link is re-established.

•

The packet loss occurs before the call drops.

•

The local end is waiting for link disconnection on the CN.

The uplink Iub interface does not receive any speech packet within 6s.

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Prescribed Action 7 for Handling Perceptual Speech Quality Problems – Take Active Actions To support the analysis conclusion and understand user perceptions, you need to take active actions to solve user complaints about perceptual speech quality problems. Step 1:

Collect information about when and where users lodge complaints and about the complained UE type.

According to the area where users lodge complaints, check whether the problem lies with: a.Indoor / outdoor. b.Common NodeBs or transmission features.

According to the complained UE type, check whether the problem lies with certain types of UEs or chips.

According to the period of time when users lodge complaints, check whether the problem occurs in peak hours.

 Step 2: Check against the checklist according to the information collected in step 1.

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Test principle: Determine the test model according to the customer complaint scenario description and UE type. Test model: Mutual CS calls, CS+PS(R99), PS (H)+CS, and third UE call Test area: Perform tests in the areas where customers lodge complaints. Test rules: Hang up each call only after both UEs confirm that there is no problem in each dialing test to avoid accidental hang-up when the fault recurs. Type of Calling Calling UE Test Called UE Test Type of Called UE Test Scenario Test Duration Test Result Information Collection UE Area Area iPhone (UE type) Complaint area

iPhone (UE type)

Complaint area

Dialing test

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

HuaweiU8800

Complaint area

iPhone (UE type)

Complaint area

Dialing test

100 dials in about two hours

Noise recurs twice on iPhone

HuaweiU8800

Complaint area

HuaweiU8800

Complaint area

Dialing test

100 dials in about two hours

No one-way audio or noise

HuaweiU8800

Complaint area

HuaweiU8800

Cross-RNC

Dialing test

100 dials in about two hours

No one-way audio or noise

HuaweiU8800

Complaint area

HuaweiU8800

Cross-MSC

Dialing test

100 dials in about two hours

No one-way audio or noise

HuaweiU8800

Complaint area

HuaweiU8800

Among carriers (PSTN)

Dialing test

100 dials in about two hours

No one-way audio or noise

HuaweiU8800

Complaint area

HuaweiU8800

Complaint area

100 dials in about two hours

One-way audio recurs twice for the calling UE

Collect complete RNC CDT, NodeB CDT, and calling UE tracing data Collect complete RNC CDT, NodeB CDT, and calling and called UE tracing data Collect complete RNC CDT, NodeB CDT, and calling and called UE tracing data Collect complete RNC CDT, NodeB CDT, and calling and called UE tracing data Collect complete RNC CDT, NodeB CDT, and calling and called UE tracing data Collect complete RNC CDT, NodeB CDT, and calling and called UE tracing data

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

iPhone

Complaint area

iPhone

Complaint area

100 dials in about two hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

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Conduct a dialing test, and the called UE removes the UE battery. Conduct a dialing test, and the calling and called UEs establish a PS service and then originate a CS call. Conduct a dialing test, and the calling and called UEs establish a PS service respectively. Conduct a dialing test, and create inter-RAT, interfrequency, and DRD handover scenarios. Conduct a dialing test, and the calling UE sends SMs to a third UE. Conduct a dialing test, and a third UE calls the calling UE. Conduct a dialing test, and the calling UE performs DTMF operations.

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Take Active Actions — Use of DTMF Functions  DTMF application scenario: For the users with single-UE CDT activated, the DTMF functions do not work. For the users with single-UE CDT not activated, they can use the DTMF functions to enable the RNC to automatically perform CDT of a single UE if one-way audio occurs during calls.

 Use Method:  Activation: *270NN#: is used to enable the RNC to perform CDT of a UE, where * indicates the start-of-DTMF-command marker, 270 indicates a functional character, NN indicates the start duration, 01 indicates one hour, and # indicates the end-of-DTMFcommand marker. In the case of one-way audio, a user can type *27001# to enable CDT.

 Deactivation: (1) The DTMF task is deleted after the UE releases the call. (2) The CDT lasts until the DTMF task is deleted. (3) The UE reports the DTMF deletion command *18000#.

 Trace the log directory:

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Handling Report of Perceptual Speech Quality Problems

Develop an analysis report template that contains the problem handling process and all factors that may affect speech quality to thoroughly analyze perceptual speech quality problems

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Typical Case 1 - Silence (Transfer) Silence caused by transfer exception 

There is silence during calls in an office.

Analysis: Action 1: Check alarms. According to log analysis, lots of link unavailable alarms are generated during Iub interface

transmission at the time point when users lodge complaints. The complaints are related to the Iub interface transfer alarms. Conclusion: Transfer exception leads to one-way audio. Users no longer experience silence on calls and there are no complaints from users after engineers replace the onsite transmission equipment and conduct dialing tests.

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Typical Case 2 - Silence (UE) Silence caused by UE problems 

An office tests the AMRC function (Adaptive Multi-Rate Control algorithm) of dozens of UEs and finds that HTC G7 and Samsung Galaxy W occasionally generates silent call issue. Analysis: Action 1: Check alarms. There is no exception. Action 2: Check known parameters : AMRC is enable Conclusion: Some UEs have the one-way audio problem after AMRC is enabled. According to the logs analysis, the uplink UE packet transmission becomes abnormal after AMRC is enabled. No speech packets are transmitted at 12.2 kbit/s in the uplink. All packets are silent or empty frames. For example, BLKSize9 indicates an empty frame, and BLKSize14 indicates silent frame.

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Typical Case 3 - Silence (Board) Silence caused by DSP overload 

There is silence during calls in an office with about 10% probability. This severely affects user experience and incurs complaints from users. Analysis: Action 1: Check alarms. There is no exception. Action 2: Check known problems for version and parameters. There is no exception. Action 3: Analyze traffic measurement. The average DSP utilization is over 80%. Conclusion: The one-way audio is caused by DSP overload. The problem is solved through DSP expansion.

DSP Usage

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A single UE receives 100 speech frames in every 2s

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number of discarded frames.

Typical Case 4 - Silence (CN Process) 15 seconds of silence caused by NSN CN call re-establishment 

Our VIP customer experiences about 10 seconds of silence during a call, and hangs up the call.

Analysis: Action 1: Check alarms. There is no exception. Action 2: Check known problems for version and parameters. There is no exception. Action 3: Analyze traffic measurement. There is no exception. Action 4: Analyze logs. There is no exception. Action 5: Make the fault recur and trace the call of a single UE. Conclusion: 1)

Compare and analyze the signaling of the calling and called UEs. The called UE experienced a call drop at 14:52:39 due to coverage problems. The call drop process appeared before one-way audio, so the silence is related to the call drop process. However, the calling UE receives a CN link release request after 15s (14:52:54), The one-way audio is related to the CN link release process before the call drop

2) Through confirmation with the customer and NSN, the call re-establishment function is enabled on the NSN CN.

Calling UE

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Called UE

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Typical Case 6 - Silence and Noise (Interference) Silence and noise caused by large-scale external burst interference 

The customer's network quality is unstable. The number of speech quality complaints increases sharply, and the RRC connection success rate fluctuates wildly. Analysis: Action 1: Check alarms. There is no exception. Action 2: Check known problems for version and parameters. There is no exception. Action 3: Analyze traffic measurement. The number of high RTWP cells changes greatly : Sometime only few cells have high RTWP, while in other time the RTWP rises abnormally at the same time in hundreds of cells. Conclusion: The noise is related to a high RTWP, and external interference according to RTWP trend.

Proof: Cells with a high RTWP appear in clusters and the interference has an identical origin, that is, external interference. According to interference signal analysis, there is strong narrowband interference that falls within a 5 Mbit/s bandwidth. Test speech quality in the time segment when interference appears. Silence and noise frequently occur and the MOS is very low. Through interference location test, a conclusion is drawn that the silence and noise are caused by self excitation of the customer's repeater. After the interference disappears, the RRC connection success rate and speech quality test result become normal. HUAWEI TECHNOLOGIES CO., LTD.

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Typical Case 6 - Noise (Product Exception) Noise caused by WBBP D board problem 

In an office , Users often experience noise.

Analysis: Action 1: Check alarms. There is no exception. Action 2: Check known problems for version and parameters. There is no exception. Action 3: Analyze traffic measurement. There is no exception. Action 4: Analyze logs. During calls, the uplink BLER is very high and there are massive packet errors, but signal quality is good.

Conclusion: The downlink signal quality on the air interface is good, the uplink RTWP is normal, and there is no packet loss during Iub interface transmission. Therefore, the noise is caused by product exceptions. Proof: Trace the call of a single UE and make the fault recur: 1) According to single-UE CDT, the RNC receives massive consecutive Uplink erroneous frames in the time segment when speech quality is poor. This proves that the noise is related to uplink bit error. 2) The air interface transmission quality and the Ec/No and RSCP Therefore, equipment exception leads to uplink bit error and therefore causes noise.

in

the

measurement

report

sent

by

the

UE

are

good.

3) According to NodeB log analysis, the uplink demodulation of D board results in a decoding exception. This problem is solved in a new NodeB version.

The uplink signal quality is good, and there are massive packet errors.

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Contents 1

MOS Evaluation Standards and Principle

2

Factors That Affect MOS and MOS Problem Handling Process and Cases

3

Perceptual Speech Quality Problems

Silence and Noise Handling Process and Cases Water Running Sound Handling Process and Cases

4

Appendix: Speech Quality Delivery Guide

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Water Running Sound Problems

• What is water running sound? Please play the attached voice file.

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Water Running Sound Detection and Adjustment ─ Principle 

Water running sound detection is implemented in the RNC. Detect IUUP packets by using AMR encoding and decoding algorithms. Extract key parameter information, for example, Linear Spectrum Frequency (LSF) and adaptive codebook index from three AMR sub-streams.

Check the incorrect mode at 3.4 KHz–20 KHz based on certain rules. If the number of continuously detected nonconformities reaches a threshold (for example, 7 abnormal frames out of 50), report the water running sound.

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Water Running Sound Detection and Adjustment Function 

In the processes that involve encryption information configuration or reconfiguration, such as AMR speech service setup, DRD, hard handover, and cell update, the service data encryption and decryption parameter ─ hyper frame number (HFN) may be set with different values on RNC and UE sides, leading to water running sound. The water running sound detection and adjustment function aims to accurately detect the water running sound in the scenarios above by using a specific detection algorithm and to eliminate the water running sound when the difference of HFNs on RNC and UE sides is 1.



If ucSpeechNoiseStatus Report is a non-zero value in the CS service information in the PCHR RAB information block, there is water running sound on calls. The time when water running sound is detected is also recorded and needs to be converted.

As shown in the figure below, the noise start time 321586992 is converted into a hexadecimal string 132B0730 where every two digits in the same color represent Hour:Minute:Second (Tick) respectively. 132B0730 is converted into a time format 19:43:07:(48).



Enable the CS DRD compatibility switch and the water running sound detection and adjustment function to avoid noise and improve user perception.



CS DRD compatibility switch:

SET UCORRMALGOSWITCH: CMPSWITCH=CMP_UU_AMR_DRD_HHO_COMPAT_SWITCH-1; 

Water running sound adjustment switch:

SET UDPUCFGDATA: AMRNOISECORRECTSWITCH=ON;

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Typical Case — Water Running Sound (Configuration) Water running sound caused by incorrect configuration 

There is water running sound on calls in an office.

Analysis: Step 1: Check known problems for version and parameters 

The version is R13SPH510.



The DRD HHO CMP switch is enabled on the live network. (SET UCORRMALGOSWITCH: CmpSwitch=CMP_UU_AMR_DRD_HHO_COMPAT_SWITCH-1;)

The SRB OVER H switch is also enabled (SET UFRCCHLTYPEPARA: SrbChlType=HSPA;), so the DRD HHO CMP switch is disabled. Conclusion: The water running sound is cased by incorrect parameter configuration. Proof: (1) According to single-UE CDT, the CS service makes a DRD and the compatibility problem is not mitigated.

(2) According to signaling, identify the reason why DRD is not made. The UE originates a PS service request. An SRB is established on UPA. The RB5 of TRB is released, and then the PS service is released.

(3) The SRB is not released, and no Iu interface is released. The UE originates a CS service, but RRC is not needed. In this case, DRD and hard handover cannot be implemented. Therefore, the compatibility switch cannot be enabled.

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Contents 1

MOS Evaluation Standards and Principle

2

Factors That Affect MOS and MOS Problem Handling Process and Cases

3

Perceptual Speech Quality Problems

Silence and Noise Handling Process and Cases Water Running Sound Handling Process and Cases

4

Appendix: Speech Quality Deliverables

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Speech Quality Related Parameters Check script parameters: Type

MML Command

Parameter ID

Default/Recommended/Baseline Value

Encryption Mode AMRC

SET UUEA SET UAMRC

EncryptionAlgo DlThdE1

UEA0-1&UEA1-1 50

Broadband AMRC

SET UAMRCWB

DlThdE1

50

Speech Activating Factor

SET UADMCTRL

UlAmrConvAF

50

Speech QOS

SET QOSACT

AMRQosPerform

NO

Redirection

SET REDIRECTION

TRAFFICTYPE

AMR

Measurement Quality

SET UQUALITYMEAS

UlAmrTrigTime6A1

D320

Congestion Setting

SET UCALLSHOCKCTRL

SysAmrRrcNum

60

Alarm Setting

SET UKPIALMTHD

AmrRabEstabSuccRatioThd

60

Admission Control

ADD UCELLCAC

UlNonCtrlThdForAMR

75

Load Control

ADD UCELLLDR

DlLdrAMRRateReductionRabNum

1

HHO Physical Channel Reconfiguration Timer

SET USTATETIMER

HoPhychRecfgTmr

5000

For the complete Baseline Settings of Speech Quality Related Parameters, see related deliverables. HUAWEI TECHNOLOGIES CO., LTD.

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Speech Quality Related Switches Check script parameters: Type TFO/TrFO TFO/TrFO AMRC

MML Command

SET UCORRMALGOSW CfgSwitch ITCH CsSwitch

AMRC DTX

CmpSwitch

VOIP service Water running sound Automatic Noise Correction Switch (R13) CS Link Reestablishment Switch

Bitmap

Default/Recommen ded/Baseline Value

CFG_DL_BLIND_DETECTION_SWI TCH

1

Parameter ID

CS_IUUP_V2_SUPPORT_SWITCH CS_AMRC_SWITCH CS_ZERO_C_AMR_CFG_TWO_CO DCH_SWITCH CMP_UU_AMR_SID_MUST_CFG_S WITCH CMP_UU_VOIP_UP_PROC_AS_NO RMAL_PS_SWITCH CMP_UU_AMR_DRD_HHO_COMPA T_SWITCH

SET UDPUCFGDATA SET URRCTRLSWITCH

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AmrNoiseCorrectSwit ch

1 0 0 0 1 0

off

RsvdPara1=RSVDBIT1_BIT24

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0

Summary of Deliverables For handling of speech quality problems including MOS improvement and user complaints, see the Guide to Troubleshooting Speech Quality.

For script parameters related to speech quality, see the UMTS Parameter Check.

Offer the WCDMA Speech Quality Feedback Checklist for frontline engineers to feed back speech quality problems. For detail, see the Analysis Report on MOS Problems in the XX Project.

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