Identifying the Agents

Identifying the AgentsCall Drop Analysis based on Huawei STS

Prepared by Mohyedeen Alkousy5/30/201111Call Drop Analysis : definition and Methods.

Meaning of Radio CDR%, TCH-DR% and CDR%.

The most helpful Huawei STS in call drop analysis.

Call Drop Investigation Process.

ideas under discussionPrepared by Mohyedeen Alkousy5/30/2011226. Using Huawei Tools to Optimize call drop.

7. How to automate the call drop analysis process.

8. One-month plan to optimize CDR% on Network level.

9.Practicing call drop analysis on real cases.

ideas under discussionPrepared by Mohyedeen Alkousy5/30/201133Call drop analysis :To Find out the direct reason(class) and if possible the indirect reason (agent) of call drop.

Direct like Interference , coverage , Hardware OOS etcIn-Direct like wrong frequencies , excessive down-tilt etc

Call Drop Analysis : definition and Methodsdirect ReasonDL/UL Interference Equipment OOSCoverage problemsIndirect ReasonHuman errors system problemsEnvironment effects

Prepared by Mohyedeen Alkousy5/30/201144 What can we analyze ?

Statistics Drive test logfiles Tracing logfiles

How can we analyze in the right way?

Choosing Decisive StatisticsFollow Investigation flow chartAccumulated knowledge databaseUsing optimization tools

Call Drop Analysis : definition and MethodsPrepared by Mohyedeen Alkousy5/30/201155Call Drop Analysis : definition and MethodsPrepared by Mohyedeen Alkousy5/30/201166What is the difference between :

Call Drop Rate (call drop rate excluding handover)

TCH Drop Rate (call drop rate including handover)

TCH RF loss rate (or radio call drop rate)

Erlang minute per dropMeaning of Radio CDR%, TCH-DR% and CDR%Prepared by Mohyedeen Alkousy5/30/201177Call Drop Rate (call drop rate excluding handover)

Meaning of Radio CDR%, TCH-DR% and CDR%No of call dropsSuccessful TCH Seizures (by call setup)Successful TCH Seizures (out handover)Successful TCH Seizures (inc handover)Prepared by Mohyedeen Alkousy5/30/2011882. Call Drop Rate (call drop rate including handover)

Meaning of Radio CDR%, TCH-DR% and CDR%No of call dropsSuccessful TCH Seizures (by call setup)Successful TCH Seizures (out handover)Successful TCH Seizures (inc handover)Prepared by Mohyedeen Alkousy5/30/2011993. TCH RF loss rate (or radio call drop rate)

Meaning of Radio CDR%, TCH-DR% and CDR%No of call dropsCaused by RF reasonsSuccessful TCH Seizures (by call setup)Successful TCH Seizures (inc handover)No of call dropsPrepared by Mohyedeen Alkousy5/30/201110104. Erlang minutes per drop

Meaning of Radio CDR%, TCH-DR% and CDR%Traffic Volume (Erlang)No of call drops60Prepared by Mohyedeen Alkousy5/30/20111111The counters should be selected carefully in order to get the best result :

The STS should be decisive

Cover all the possible root causes

Guide us to causes not the effects

Easy to visualize and analyze

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20111212Radio Link Failure Measurements (RLF)Drop Causes distributionInterference On Idle mode measurements (IOI)Radio Quality Index Measurements (RQI)Balance/Unbalance MeasurementsCorrelated level and quality measurements E1 Bit errors measurements and TCH availabilityHardware Alarms

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20111313Radio Link Failure Measurements (RLF)

Very important because it will give an idea about the link condition when the drop happened

The most helpful Huawei STS in call drop analysis

MRMRMRMRMR

Record the last 3 or 4 measurement reports before the drop happen BTS

MSPrepared by Mohyedeen Alkousy5/30/20111414Mean Rxlevel (value-110) dB = (Rxlev in MR1+Rxlev in MR2+Rxlev in MR3 +.)/ Number of measurement reportsSame calculation for Rxquality and TAMore accumulated values means more accuracy

1512514156131123042145211512514156131123042145214211156151075Rx level: 10Rx Qual: 5TA: 62The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20111515Since these counters are on TRX Level it will be affected by Base band hopping

The most helpful Huawei STS in call drop analysis RLF Counters (Full rate)S4307D:Uplink Level during Radio Link Failure S4317D:Uplink Quality during Radio Link Failure S4327D:Downlink Level during Radio Link Failure S4337D:Downlink Quality during Radio Link Failure S4347D:TA during Radio Link Failure S4357D:Radio Link Failures RLF Counters (Half rate)S4308D:Uplink Level during Radio Link Failure (TCHH)S4318D:Uplink Quality during Radio Link Failure (TCHH)S4328D:Downlink Level during Radio Link Failure (TCHH)S4338D:Downlink Quality during Radio Link Failure (TCHH)S4348D:TA during Radio Link Failure (TCHH)S4358D:Radio Link Failures (TCHH)Prepared by Mohyedeen Alkousy5/30/20111616How to use RLF measurements in analysis :

The most helpful Huawei STS in call drop analysisRX LevelLOWHIGHBADGOODNEARFARTime AdvanceRX QualityPrepared by Mohyedeen Alkousy5/30/20111717Examples:In case of interference :

The most helpful Huawei STS in call drop analysisRX LevelLOWHIGHBADGOODNEARFARTime AdvanceRX QualityPrepared by Mohyedeen Alkousy5/30/20111818Examples:In case of coverage problem:

The most helpful Huawei STS in call drop analysisRX LevelLOWHIGHBADGOODNEARFARTime AdvanceRX QualityPrepared by Mohyedeen Alkousy5/30/20111919Examples:In case of sudden drop due to faulty hardware:

The most helpful Huawei STS in call drop analysisRX LevelLOWHIGHBADGOODNEARFARTime AdvanceRX QualityPrepared by Mohyedeen Alkousy5/30/20112020Drop Causes distribution

Counters will be begged according to the messages or events between BTS-BSC-MSC that caused the release of TCH resources.

There are 18 different causes in Huawei but 4 of them are important and the rest rarely triggered.

By using the drop causes STS we can classify if the drop is due to Hardware or RF and if the drop happened during stable or handover state

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20112121The most helpful Huawei STS in call drop analysisDrop Causes CountersM3100A:Call Drops due to ERR IND Received (T200 Expired)M3100B:Call Drops due to ERR IND Received (Unsolicited DM Response)M3100C:Call Drops due to ERR IND Received (Sequence Error)M3101A:Call Drops due to CONN FAIL Received (Radio Link Failure)M3101B:Call Drops due to CONN FAIL Received (HO Access Failure)M3101C:Call Drops due to CONN FAIL Received (OM Intervention)M3101D:Call Drops due to CONN FAIL Received (Radio Resource Unavail)M3101E:Call Drops due to CONN FAIL Received (Other Causes)M3102:Call Drops due to REL IND Received M312:Call Drops due to No MRs from MS for a Long TimeM313:Call Drops due to Abis Terrestrial Link Failure M314:Call Drops due to Equipment Failure M315:Call Drops due to Forced Handover M316:Call Drops due to Resource Check M319B:Clear Requests Sent on the A Interface in Handover State RM3173:Call Drops Due to Loopback Start FailureRM3174:Call Drops Due to Failures to Return to Normal Call from Loopback CM339C:Clear Requests Sent on the A interface (TA Limit)Most of drops in these 4 reasonsPrepared by Mohyedeen Alkousy5/30/20112222The most helpful Huawei STS in call drop analysisBad Rx-Qual on UL/DLSignal decreased sharplyCell OOSLayer 2 messages unacknowledgedSACCH Messages not decoded from MS or BTST200 expiredN200+1 timesLapd layer 2 FailureRLT expiredLayer 3 FailureErr. Indication sent from BTS to BSCConnection Failure sent from BTS to BSCClear request sent from BSC to MSC and Clear request sent from BSC to MSC and CALL DROP T200reason triggered is error indication (T200 expired)CALL DROP RLTreason triggered is conn. failure (radio link failure)Prepared by Mohyedeen Alkousy5/30/20112323The most helpful Huawei STS in call drop analysisTRX , Cell or Site out of serviceCALL DROP EQUIPreason triggered is Equipment failureHardware ProblemsTRX , Combiner , GTMUCALL DROP ABISreason triggered Abis terrestrial failureAbis Transmission ProblemsSynchronization ,high BERSite out of servicePrepared by Mohyedeen Alkousy5/30/20112424 Most of the drops in the network are caused by RF problems, it means that we can bring further Improvement on the call drop rate

Percentage of dropDue to T200 compared to RLT depend on Timer settings

The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/20112525 Interference On Idle mode measurements (IOI)

Very helpful in distinguishing between internal and external InterferenceThe existence of high values in Band 3,4 and 5 confirm Interference but the opposite is not true.Might give wrong averaged values in case if BB hopping is active since they are on TRX level.It only shows the uplink interferenceThresholds between bands can be changed to test special range of level.Sometimes it will not express the real strength of interference since the measuring point is not the same place as the interfered area.

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20112626 Interference On Idle mode measurements (IOI):

The most helpful Huawei STS in call drop analysisIOI Measurements AS4207A:TCHFs in Interference Band 1AS4207B:TCHFs in Interference Band 2AS4207C:TCHFs in Interference Band 3AS4207D:TCHFs in Interference Band 4AS4207E:TCHFs in Interference Band 5IOI Measurements (TCHH)AS4208A:TCHHs in Interference Band 1AS4208B:TCHHs in Interference Band 2AS4208C:TCHHs in Interference Band 3AS4208D:TCHHs in Interference Band 4AS4208E:TCHHs in Interference Band 5Number of highly interfered TSsWith level > -90 dBmPrepared by Mohyedeen Alkousy5/30/20112727Internal Interference effect on IOI measure (strong)The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/20112828Internal Interference effect on IOI measure (weak)The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/20112929External Interference effect on IOI measure (strong):The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/20113030External Interference effect on IOI measure (weak effect):The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/201131314. Radio Quality Index (RQI):

We can use it only if AMR is activated.Radio quality index is the dB value of C/I multiplied by 2 RQI = 2 * C/I ( dBm) .RQI represent the C/I values in the uplink only.We can get RQI of all Mobiles per TA and by comparing it to RLF per TA we can tell the RQI values in areas which suffer from high radio link failures.RQI range of values[055+] = 2 * C/I range of values [030].RQI values less than 18 (C/I = 9) indicate very bad quality and strong interference.Since RQI values given on TRX level we might get wrong averaged values in case of BB hopping is activated.

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/201132324. Radio Quality Index (RQI): The most helpful Huawei STS in call drop analysisRQI MeasurementsS4400E:Number of Measurement Reports (RQI = 0 to 1)S4401E:Number of Measurement Reports (RQI = 1 to 2)S4402E:Number of Measurement Reports (RQI = 2 to 3). . . .. . . .S4418E:Number of Measurement Reports (RQI = 45 to 55)S4419E:Number of Measurement Reports (RQI greater than 55)S4440E:Number of Measurement Reports with RQIRQI MeasurementsS4400C:MRs with RQI (TA = 0)S4401C:MRs with RQI (TA = 1)S4402C:MRs with RQI (TA = 2)...S4455C:MRs with RQI (TA = 55 to 63)S4463C:MRs with RQI (TA greater than 63)RQI MeasurementsS4400D:RQI (TA = 0)S4401D:RQI (TA = 1)S4402D:RQI (TA = 2)...S4455D:RQI (TA = 55 to 63)S4463D:RQI (TA greater than 63)Prepared by Mohyedeen Alkousy5/30/201133334. Radio Quality Index (RQI): The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/201134344. Radio Quality Index (RQI): The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/201135354. Balance/Un-Balance Measurements:

Used usually to detect Problems in RF Path (RF Path include antenna , feeders , Jumpers , CDU, DDPU , DCOM and Carrier receivers).Having unbalanced measurements on uplink or downlink indicate that we have path problem but the opposite is not necessarily true.We can determine if the problem on uplink or downlink but getting deeper may require the help of regional team to visit the site.In case of BB hopping we should disable it to know the problematic TRX , this will help the regional team a lot in solving the problem.

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20113636The most helpful Huawei STS in call drop analysis

Downlink high lossUplink high lossPrepared by Mohyedeen Alkousy5/30/20113737The most helpful Huawei STS in call drop analysis

Downlink high lossUplink high lossPrepared by Mohyedeen Alkousy5/30/20113838Correlated level and quality measurements

The most helpful Huawei STS in call drop analysisWeakest levelsStrongest levelsWorst qualityBest qualityPrepared by Mohyedeen Alkousy5/30/20113939Correlated level and quality measurements

Give an idea about the situation of quality and level in all the cell not like RLF measurementsAffected by BB hopping since the STS given on TRX levelInclude 128 counters for FR and 128 for HRBetter to be analyzed by 3D chart since its three dimension Matrix

The most helpful Huawei STS in call drop analysis

Prepared by Mohyedeen Alkousy5/30/20114040E1 Bit errors and CRC check and TCH AvailabilityWe have many STS that give the seconds of error during the transmission ,CRC check and badly received or sent frames.These counters can help in identifying the drops caused by Abis interface Problems.TCH availability check is necessary to make sure the call drop is not caused by Hardware ProblemsAlarmsAlarms should take a priority in Optimization process to eliminate any possibility of Hardware issues.Its important to know that if the alarm exist then we have hardware Problem but the opposite is not true

The most helpful Huawei STS in call drop analysisPrepared by Mohyedeen Alkousy5/30/20114141Its very important to choose the right procedure to analyze the call drops.The procedure should be adequate for Mobilis problems.The procedure should be the initial schema for automating of call drop optimization process.Follow the rule : the larger problem should take priority.Two methods ,either check every thing starting from the important or follow the cause effect chain by using the correct counters.

Call Drop Investigation flowchartPrepared by Mohyedeen Alkousy5/30/20114242Shown Flow chart usually used In CDR analysis , but is that the correct way to optimize the call drop in Mobilis ??

Call Drop Investigation flow chart

Prepared by Mohyedeen Alkousy5/30/20114343Call Drop Investigation flow chart

General Flow ChartPrepared by Mohyedeen Alkousy5/30/20114444Automating the call Drop Analysis depend on the following point :

Reducing the time needed to Visualize the data

Time needed for analysis

The availability of knowledge database to directly correlate or compare the new problems and determine the reason

How to Automate Call Drop Analysis ProcessPrepared by Mohyedeen Alkousy5/30/20114545Reducing the time needed to Visualize the data

One of the most Important actions that must be taken by Optimizer is to prepare the adequate post processing tool or Macro that will import the raw counters and convert them to different charts and tables that is easy to analyze.

Target of the macro not analyze the data but to help in analyzing by better visualizing

Calculation on the raw counters are needed to reduce the number of data shown and to give more meaningful charts

How to Automate Call Drop Analysis Prepared by Mohyedeen Alkousy5/30/20114646Time needed for analysis :

the Optimizer capability to analyze.Using different methods of analysis.Cannot be done by macro or Optimizer created tools but can be done faster by using vendor Optimization tools like NASTAR, and other tools.

The availability of knowledge database :The good Optimizer should always record a history of problems that he encountered during his work.yet its better to develop the small macro suggested earlier to save the history of STS to small knowledge database that can be used later for correlation.

How to Automate Call Drop Analysis Prepared by Mohyedeen Alkousy5/30/20114747How to Automate Call Drop Analysis Done by the OptimizerDone by the OptimizerDone by the OptimizerDone by the MacroDone by theMacroVISUALIZING STSSAVE IN KNOWLEDGE DATABASEPrepare the raw countersAnalyze the ProblemAccumulated Knowledge databasePrepared by Mohyedeen Alkousy5/30/20114848Since most of the drop in Mobilis is caused by RF reasonsIts Possible to bring huge Improvements to the network by putting an organized Optimization Plan .

Key factors to speed up the implementation of the plan :

Solve by Groups not one by oneSolve easiest problems firstUsing the macro and analysis tools as much as possibleActivating all the features that could bring further enhancement to Voice or Frequency planFollow the investigation flow chart

One Month Plan to Improve CDR on Network LevelPrepared by Mohyedeen Alkousy5/30/20114949Sheet2

YESNO NOT SUREIs it RF Problem??CDR% Thresholds exceeded?Is it Hardware Problem??HOW to Check ?1.check drop cause distribution ? T200 and RLT are the dominant reasons2.Check Interference on Idle Mode?2.check radio link failure (RLF) if we have bad level or bad quaity?3. check Cell frequency scan ?4.check correlated LEV & quality zones , are we in interference zone or bad coverage zone?HOW to Check ?1.Check Alarms History?2.Check call drop distribution , dominant causes are equipment or Abis ?3. check E1 error,CRC and TCH availability ?4.check balance unBalance measurements , do I have un acceptable levels?YESIs it Software Problem??HOW to Check ?1. check any alarms related to software appeared in history ?2.is the problem on site level or cell level ?3. is there any synchronization problems. check by trace and check handover success is it normal?4.check software compatabilityNO NOT SURENO NOT SUREYESPROBLEM SCALEPROBLEM APPEARANCE DATEHOW PROBLEM TRIGGEREDTESTING ACTIONs1.Internal VS External2. One TRX VS Many TRXs3.Near area VS Overshooting area4. Intensive VS Light4.1.Uplink VS Downlink2. One TRX VS Many TRXs3.Near area VS Overshooting area4.Intensive weakness VS light weaknessIs it Interference Problem??Is it weak level Problem??YESNO NOT SUREYESNO NOT SURETAKE ACTIONPROBLEM SCALEPROBLEM APPEARANCE DATEHOW PROBLEM TRIGGEREDTESTING ACTIONsIs it Abis Problem??Is it equipment Problem??YESNO NOT SUREYESNO NOT SUREIs it RF Path Problem??NO NOT SUREYESPROBLEM SCALEPROBLEM APPEARANCE DATEHOW PROBLEM TRIGGEREDTESTING ACTIONsEscalate the Problem

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