analysis report on perceptual speech quality problems of xx project

Analysis Report on Perceptual Speech Quality Problems of XX Project PUBLIC

Analysis Report on Perceptual Speech Quality Problems of XX Project

XX department XX November 27, 2012

1 Overview1.1 Background

Briefly describe project background, including project name and scale.

Project background:

Project scale:

1.2 ProblemsDescribe the current problems and detailed information about complaints.

Introduction to problems: When two customers call each other, one-way audio symptom occurs, namely, one party cannot hear any voice.

1.3 Versions and transmission ModesDescribe versions of NEs, such as BSC and BTS, on the live network. If multiple versions are involved, specify all the versions. If version upgrades are involved, specify the versions before and after upgrade, the upgrade time, and transmission modes.

CN Manufacturer: EricssonBSC version: V900R013ENGC01SPH556

BTS version: BTS3000V100R012C00SPC048 (3900 series)

BTS3000V100R008C12SPC018 (3900E)

Transmission mode: ATM or IP, shown as in the following figure:

2023-04-18 Huawei confidential. No spreading without permission. of 13

app:ds:Ericsson


2 Implementation of Required ActionsProvide the implementation results from required actions, including necessary deliverables, troubleshooting results, and current difficulties.

Required Action Completion Status

Engineer Name

Deliverable and Check Result

Required action 1: Checking alarms Completed A N

Required action 2: Checking versions and parameters for known problems

Completed B Y

Required Action 3: Checking UEs



Required Action Completion Status

Engineer Name

Deliverable and Check Result

Required action 4: Checking and analyzing traffic statistics

Ongoing C N

Required action 5: Checking and analyzing logs

Ongoing D N

Required action 6: Tracing and analyzing a single UE

Not started E N

Required action 7: Taking active actions Partially completed

F Y

3 Detailed Analysis of Required Actions3.1 Required Action 1: Checking Alarms

3.1.1 Analyzing Alarm LogsCheck alarms based on cells, NodeBs, boards, and transmission devices in the complaint area.

Classification of Perceptual Speech Quality Problems

Alarm Type Alarm ID Check Result Check Result

One-way audio and silence

DSP CPU overload alarm

ALM-22501 DSP CPU overload alarm

Y/N Y/N

Interface board forwarding overload alarm

ALM-20275 interface board forwarding overload alarm

Y/N Y/N

Transmission-related alarms

ALM-21352 IPPATH excessive packet loss alarm

Y/N Y/N

ALM-21221 IMA link out-of-frame alarm

Y/N Y/N

ALM-21202 E1/T1 out-of-frame alarm

Y/N Y/N

ALM-21208 E1/T1 excessive slip frame

Y/N Y/N




Alarm Type Alarm ID Check Result Check Result

alarm

ALM-21223 IMA link remote receiving fault alarm

Y/N Y/N

Clock-related alarms ALM-20205 system clock source unavailable alarm

Y/N Y/N

ALM-20211 DSP time synchronization exception alarm

Y/N

ALM-20209 clock phase-lock loop fault alarm

Y/N

NodeB-related alarms ALM-20209 DL ASIC Chip Encoding Resource Faulty

Y/N

Noise Transmission-related alarms

ALM-21351 excessive IP transport layer errored frame alarm

Y/N

ALM-21207 E1/T1 excessive BER alarm

Y/N

3.1.2 ConclusionCheck whether alarms are generated in NEs and transmission links to identify causes affecting voice quality.

3.2 Required Action 2: Checking Versions and Parameters for Known Problems

3.2.1 Checking Versions and Parameters for Known Problems

Check known version problems of NodeBs based on the version information in the complaint area, and check known RNC-level problems affecting voice quality.




Version & Parameter

Impact Check Result

Known noise problems

Check the NodeB D board version that has speech quality problems.

R12 V200R012C00SPC440 (earlier versions) Y/N

R13 V200R013C00SPC310 (earlier versions) Y/N

Known one-way audio and silence problems

Check RNC parameters and enable the AMRC switch.

SET UCORRMALGOSWITCH: CsSwitch=CS_AMRC_SWITCH-1;

Y/N

Known garble noise problems

Check RNC parameters and disable the DRD HHO CMP switch.

SET UCORRMALGOSWITCH: CmpSwitch=CMP_UU_AMR_DRD_HHO_COMPAT_SWITCH-0;

Y/N

Check RNC parameters and enable the SRB OVER H switch.

SET UFRCCHLTYPEPARA: SrbChlType=HSPA; Y/N

Known MOS problems

Check RNC parameters and enable the OLPC BLER adjust switch.

SET URRMCDLCFG:INNERSWITCH1=OLPC_BLER_COEF_ADJUST_SWITCH_13-0; (versions earlier than SPC550)

SET UCORRMPARA: ReservedSwitch0=RESERVED_SWITCH_0_BIT24-1; (versions later than SPC550)

3.2.2 ConclusionModify incorrect parameters based on parameter check results and draw conclusions.

3.3 Required Action 3: Checking UEs

Serial Number Method Check Result

1 Comparing UEs by tests What are the comparison results of UEs?

2 Checking UE compatibility against the bug list

Yes or No? If yes, specify the UE type.

3 Filtering logs Yes or No? If yes, specify the UE type.



3.3.1 ConclusionCheck impacts of abnormal UEs on voice quality based on the check results and draw conclusions.

3.4 Required Action 4: Checking and Analyzing Traffic Statistics

3.4.1 Check and Analyze Traffic StatisticsCheck boards-level, cell-level, and transmission problems based on traffic statistics. Provide check results, as shown in the following table:

Complaints

Complaint Area Counter Check Results

One-way audio

DSP board-level area VS.DSP.UsagePeak>90%, VS.DSP.UsageAvg>70%

Y/N

cell-level area VS.CS.CallDrop.Cell.Rate>2% Y/N

NodeB transmission area

ATM VS.AAL2PATH.PVCLAYER.DROPFORHEADCELLS, VS.AAL2PATH.PVCLAYER.DROPFORRXOVERFLOWCELLS, VS.AAL2PATH.PVCLAYER.DROPFORTXOVERFLOWCELLS.

The number of lost packets is more than 60.

Y/N

IP IPPM activated

VS.IPPM.Forword.Peak.DropRates>1% Y/N

IPPM not activated

VS.IPPATH.IPLAYER.TXDROPPACKETS, VS.IPPATH.IPLAYER.RXDROPPACKETS.

The number of lost packets is more than 60.

Y/N

Noise cell-level VS.Speech.VQI.Bad>5%, VS.Speech.VQI.Accept<90%, VS.Speech.VQI.Good<90%, VS.ULBlerAMR>1%

Y/N

3.4.2 ConclusionInitially identify problems based on traffic statistics and provide analysis results.



3.5 Required Action 5: Checking and Analyzing Logs

3.5.1 Check and analyze logsProvide judgment results of different scenarios based on log analysis in complaint areas.

Analysis of one-way audio and silence:

Import the PCHR logs generated in the complaint period, and output the one-way audio count: ucAmrSilentNum.

Judgment criteria: If ucAmrSilentNum is greater than 0, one-way audio occurs in the call and the one-way audio count is X

Identify whether one-way audio occurs: Y/N

Analysis of noise:

BLER analysis:

Uplink BLER count at rank 1: BLER_RANK1_TIMES.





Uplink BLER count at rank 6: BLER_RANK6_TIMES

Judgment criteria: If (rank 5+6)/(rank 1+2+3+4+5+6) > 5%, the noise is related to uplink bit error;

Identify whether noise results from high BLER: Y/N

Analysis of garble noise:

Judgment criteria:

If ucSpeechNoiseStatusReport > 0 (subject to the AMR adjustment switch), ucHfnAdjustState ≤ 4 (subject to the AMR adjustment switch), and the start time of garble noise detection SpeechNoiseTime > 0, there is garble noise on the call at the time of XXX

Identify whether garble noise exists: Y/N

3.5.2 ConclusionJudge whether abnormal voice records exist according to the PCHR analysis and provide judgment results.

3.6 Required Action 6: Tracing and Analyzing a Single UE

3.6.1 Trace and Analyze a single UE Verify whether noise and one-way audio exists based on logs related to problems that recur.



Noise: uplink bit error

Analyze the air interface transmission quality through user plane data and judge packet errors on the air interface based on the CRCI in the FP packet. There is one cyclic redundancy check indicator (CRCI) bit in the FP frame with the value range of {0=Correct, 1=Not Correct}.

Judgment criteria: If usULCrciErrNum/ulULRcvTbNum > 1%, the noise is caused by uplink bit error.

The following is the calculation method:

Figure 3-1 A speech packet is received at an interval of 20 ms

Figure 3-2 All speech packets and CRC error packets received in uplink



Verify whether noise is related to the bit errors:

One-way audio: FP analysis

According to UMTS speech feature, a speech packet is sent at a transmission time interval (TTI) of 20 ms based on UMTS networks. 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 of them are empty at the time point when a complaint is lodged, one-way audio is related to the Iub interface transmission, RAN process, UEs or NodeB equipment.

Verify whether a frame is added in FP packets every 20 ms:

One-way audio: IUUP analysis

According to UMTS speech feature, a speech packet is sent at a TTI of 20 ms based on UMTS networks. 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 at the time point when a complaint is lodged, one-way audio is related to the Iu interface transmission or CN.


The cumulative number of uplink speech packets on the

Iub interface does not increase in 8s.


Verify whether a frame is added in IUUP packets every 20 ms:

3.6.2 ConclusionVerify whether a frame is not added in the FP or IUUP packets every 20 seconds.


The cumulative number of downlink speech packets on the Iu interface does

not increase in 10s.


3.7 Required Action 7: Taking Active ActionsIf root causes to problems are still not located after the preceding actions, carry out dialing tests by referring to the following methods:

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: Carry out dialing tests every 5 to 10 minutes, and 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.

Test model: Mutual CS calls, CS+PS(R99), PS (H)+CS, and third UE call

Type of Calling UE

Calling UE Test Area

Type of Called UE

Called UE Test Area

Test Scenario

Test

Duration

Test Result

Information Collection

iPhone (UE type)

Complaint area

iPhone (UE type)

Complaint area

Dialing test 500 dials in about 48 hours

No one-way audio or noise

Collect complete RNC CDT and NodeB CDT

U121E Complaint area

iPhone (UE type)

Complaint area


Noise recurs twice on iPhone

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

U121E complaint area





U121E complaint area


Conduct a dialing test, and the called UE removes the UE battery.

500 dials in about 48 hours

One-way audio recurs twice for the calling UE


IPHONE Complaint area


Conduct a dialing test, and the calling and called UEs establish a PS service






respectively.



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.




3.7.1 ConclusionProvide dialing test results.

4 ConclusionDraw conclusions according to the analysis and summary of the required actions. Provide conclusive opinions such as the current possible problems, the measures that can be taken, other required troubleshooting methods, and the required data support.

According to the preceding analysis, the following conclusions are drawn:

1. Alarms are generated.

2. Some known parameters are incorrectly set.

3. High block error rate (BLER) exists.

Requirements for feedback:

1. Provide reports related to performed actions.

2. Provide parameter configuration files.

3. Provide traffic statistic files.

4. Provide alarm logs.

5. Provide call history record (CHR) logs.



5 Monitoring Optimization MeasuresMonitor the application time, application scope, and application effect of every optimization measure. In addition, provide a comparison report on the application of a measure, including analysis of indicator changes before and after application of the measure, gain analysis, and analysis of other influences.


analysis report on perceptual speech quality problems of xx project

Documents

checking versions

alarm logs check alarms

check result required

e1t1 excessive ber alarm

current problems

version problems of

versions of nes

multiple versions