02 GO_NA09_E1_1 GSM Traffic Statistics Analysis-72

GSM Traffic Statistics AnalysisZTE university

Course TargetWhen you finish studying this courseyou canMaster ZTE traffic statisticMaster the meaning of parameter items of common-used traffic statisticMaster the methods to analyze and position the problems making use of traffic statistic

Contents ZTE Traffic Statistic OverviewDefinitions Of Main Traffic Statistic ParametersPosition And Analyze Problems Making Use Of Traffic StatisticTraffic Statistic Analysis Cases

ZTE Traffic Statistic Overview--The Function Of Traffic Statistic AnalysisOptimization methodRadio Network OptimizationData collectionoptimization method implementationLight adjustment solution and evaluationTraffic statistic analysisKnow network performance index Provide clients with quantitative service guidelines Monitor network performance Position and analyze network problemsImprove network running quality

ZTE Traffic Statistic Overview--ZTE Traffic Statistic Introduce

ZTE Traffic Statistic Overview-- Traffic Statistic IndexOriginal traffic statistic indexSDCCH congestion rateSDCCH assignment success rate SDCCH call drop rate TCH congestion rateTCH assignment success rate TCH call drop rate Handover success rate Random access success ratePaging success rate (correlative index)Synthetical traffic statistic indexTraffic-to-drop ratioWorst cell ratioTCH assignment success rate (China Union definition)Radio connection rate

Definitions Of Key Traffic Statistics Indicators -- SDCCH blocking rate

KPI nameSDCCH blocking ratedefinitionNumber of SDCCH blockings*100%/Number of SDCCH call attemptsV3 (6.20)(C900060005+C900060011+C900060039)*100%/(C900060003+C900060010+C900060038)

Definitions Of Key Traffic Statistics Indicators --Signaling statistical point of SDCCH blocking

MS

BTS

BSC

CHL_REQ

CHL_RQD

A1

CHL_ACT

CHL_ACT_ACK

A2

IMM_ASS_CMD

IMM_ASS

SABM

EST_IND

A3

SD blocking

SD assignment success

Definitions Of Key Traffic Statistics Indicators -- TCH blocking rate

KPI nameTCH blocking rateDefinition Number of TCH blockings *100%/ Number of TCH call attemptsV3 (6.20)(C900060020+C900060031+C900060043+C900060047)*100%/(C900060019+C900060030+C900060042+C900060046)

Definitions Of Key Traffic Statistics Indicators --Signaling statistical point of TCH blocking

MS

BTS

BSC

CHL_ACT_ACK

UA

B1

ASS_COM

CHL_ACT

ASS_CMD

ASS_COM

B2

ASS_CMD

ASS_CMD

SABM

EST_IND

B3

MSC

ASS_COM

B4

Definitions Of Key Traffic Statistics Indicators --TCH assignment success rate

KPI nameTCH assignment success rateDefinitionNumber of TCH assignment successes*100/(Number of TCH assignment successes + Number of TCH assignment failures) V3 (V6.20)((C900060028+C900060036+C900060199+C900060210+C900060017+C900060235)*100/(C900060028+C900060036+C900060199+C900060210+C900060017+C900060235+C900060029+C900060037+C900060200+C900060211+C900060018+C900060135)

Definitions Of Key Traffic Statistics Signaling statistical point of TCH assignment success rate

MS

BTS

BSC

CHL_ACT_ACK

UA

B1

ASS_COM

CHL_ACT

ASS_CMD

ASS_COM

B2

ASS_CMD

ASS_CMD

SABM

EST_IND

B3

MSC

ASS_COM

B4

Definitions Of Key Traffic Statistics -- Signaling statistical point of TCH assignment failureMS sends Assignment Failure to BSC after the assignment fails.After T3107 expires, BSC counts assignment failure for one time.

Definitions Of Key Traffic Statistics --TCH call drop rate

KPI nameTCH drop rate / Call drop rateDefinitionNumber of TCH call drops*100%/Number of TCH assignment successesV3 (V6.20)(C900060054+C900060055)*100/(C900060028+C900060036+C900060199+C900060210)

Definitions Of Key Traffic Statistics IndicatorsSignaling statistical point of radio call drops

BTS

BSC

Measure Report

MSC

Measure Result

Connection failure

Ms

Clear Request(Radio Interface Failure)

A1

Definitions Of Key Traffic Statistics IndicatorsSignaling statistical point of call drops due to handoversCall drop due to intra-cell handover Call drop due to inter-BSC handoverCall drop due to inter-BSC handoverThe signaling statistical point for call drops due to all kinds of handovers is A2, which means after the timer expires due to handover failure, BSC clears the channels and counts one time of call drop due to handover failure.

A1

BSC

BTS:TRX

MS

ASSIGNMENT COMMAND

CHANNEL ACTIVATE

A2

CHANNEL ACTIVATE ACK

SET T3107

T3107 Timeout

A1

BSC

Old BTS:

MS

HANDOVER COMMAND

CHANNEL ACT

A2

CHANNEL ACT ACK

SET T3103

New BTS

HANDOVER COMMAND

T3103 Timeout

A1

BSC

Old BTS:

MS

HANDOVER COMMAND

CHANNEL ACT

A2

CHANNEL ACT ACK

SET T8

New BTS

HANDOVER COMMAND

T8 Timeout

Definitions Of Key Traffic Statistics --TCH handover success rate

KPI nameHandover success rateDefinitionNumber of busy-hour handover successes*100%/ Number of busy-hour handover requestsV3 (V6.20)(C900060098+C900060102+C900060120)*100/(C900060097+C900060213+C900060214+C900060215+C900060099+C900060100+C900060101+C900060216+C900060119)

Definitions Of Key Traffic Statistics Indicators -- Signaling statistical point of TCH handover success rateThe signaling statistical point of intra-cell handover request is C1, and that of handover success is C3, which means Assign Complete message is received by BSC after the handover is completed successfully.

MS

BTS

BSC

C1

CHL_ACT

C2

ASS_CMD

ASS_CMD

SABM

EST_IND

C3

MSC

MEAS_RES

CHL_ACT_ACK

UA

ASS_COM

ASS_COM

HO_PREFORM

MEAS_REP

Definitions Of Key Traffic Statistics Indicators --Signaling statistical point of TCH handover success rateThe signaling statistical point of intra-BSC handover request is A4, which means the message received by BSC is incoming handover request. The signaling statistical point of handover success is A6, which means the Handover Complete message is received after the handover is completed successfully.

A1

BSC:Ori_Cell

BTS:Ori_Cell

MS

HANDOVER COMMAND

CHANNEL ACT

A2

CHANNEL ACT ACK

HANDOVER COMPLETE

BTS:Des_Cell

HANDOVER COMMAND

HANDOVER COMPLETE

Measurement Report

Handover Algorithm

A3

BSC:Des_Cell

RADIO APPLY

RADIO AVAIL

Measurement Report

HANDOVER COMPLETE

A4

A5

A6

Definitions Of Key Traffic Statistics Indicators -- Signaling statistical point of TCH handover success rateThe signaling statistical point of inter-BSC handover request is D1, which means the handover request message sent by MSC is received. The signaling statistical point of handover success is D3, which represents that Handover Complete message is received.

MS

BTS

BSC

D1

CHL_ACT

HO_REQ

D2

HO_DETECT

HO_ACCESS

SABM

HO_DETECT

D3

MSC

CHL_ACT_ACK

UA

HO_COM

HO_COM

HO_COM

HO_REQ_ACK

PHY_INFO

Definitions Of Key Traffic Statistics Indicators -- DL TBF establishment success rate

KPI nameDL TBF establishment success rateDefinitionNumber of GPRS DL signaling TBF establishment + Number of GPRS DL data TBF establishment + Number of EGPRS DL signaling TBF establishment + Number of EGPRS DL data TBF establishment *100% / Number of DL packet channel requests V3V3 (V6.20)(C900040007+C900040015+C900040008+C900040016)*100/(C900040141+C900040142+C900040143+C900040144+C900040145+C900040146+C900040147+C900040148)

Definitions Of Key Traffic Statistics Indicators -- Signaling statistical point of DL TBF establishment success rateStatistical point of DL TBF establishment before T3192 expires: AStatistical point of DL TBF establishment with existing resource: AStatistical point of DL TBF establishment on the PACCH of UL TBF: A2

MS

SGSN

BSC

LLC Frame

RLC Block

LLC Frame

RLC Block

RLC BlockFBI1

Start T3193

A

Packet Downlink Assignment

LLC Frame

MS

SGSN

BSC

RLC Block

RLC Block

RLC Block

A

Packet Downlink Assignment(Packet Timeslot Reconfigure)

LLC Frame

Definitions Of Key Traffic Statistics IndicatorsUL TBF establishment success rate

KPI nameUL TBF establishment success rateDefinitionNumber of GPRS UL signaling TBF establishment + Number of GPRS UL data TBF establishment + Number of EGPRS UL signaling TBF establishment + Number of EGPRS UL data TBF establishment *100% / Number of UL packet channel requests V3V3 (V6.20)(C900040025+C900040033+C900040026+C900040034)*100/(C900040159+C900040160+C900040161+C900040168+C900040163+C900040164+C900040165+C900040166)

Definitions Of Key Traffic Statistics IndicatorsSignaling statistical point of UL TBF establishment success rateUL TBF establishment consists of two modes: one-phase access (left figure) and two-step access (right figure); the statistical point of access success is A1.

MS

BSS

A1

Channel Request/Packet Channel Request

Immediate Assignment/Packet Uplink Assignment

Rlc Data Block/Packet Resource Request/Additional MS Radio Access Capabilities

Packet Uplink AckFAI=0TLLI

Data BlockCV!=0TLLI

Data BlockCV=0

P_UPLINK_ACKFAI=1

P_CTRL_ACK

A2

MS

BSS

A1

Channel Request/Packet Channel Request

Immediate Assignment/Packet Uplink Assignment

Packet Resource Request

Packet Uplink AckFAI=0

Data BlockCV!=0

Data BlockCV=0

P_UPLINK_ACKFAI=1

P_CTRL_ACK

A2

Packet Uplink Assignment

Position And Analyze Problems with Traffic Statistics-- Traffic Statistic Analysis ContentCall Drop Problems AnalysisSDCCH assignment problems analysisTCH congestion problems analysisSDCCH congestion problems analysisHandover problem analysisTCH assignment problems analysisTraffic Statistic Analysis Content

Position And Analyze Problems with Traffic StatisticsWhole Principle of Traffic Statistic AnalysisWhole PrincipleFrom whole problem to the particular problem, from one-day network index observation to one-week network index, from single index to their correlation, from the key cells to subordinate cells.Before Traffic Statistic AnalysisCollect overall data, including all kinds of performance reports and measurement data, and need to know such basic information as networking structure. Carry out Traffic Statistic Analysis Based on the principle of grasp the situation macroscopically, handle it microscopically and characteristics of traffic statistic data, traffic statistic analysis is a process from the whole network performance measurements to the cells performance measurements, and a gradual process from the main index to subordinate index. It analyzes network performance index first, with a clear grasp of the whole network index, then determines which index are worse, finally analyzes the main cells which cause worse index.Combine with other network optimization toolsDuring traffic statistic analyzing, it needs to combine with other network optimization tools to position and analyze problems.

Position And Analyze Problems with Traffic StatisticsTOP Analyze MethodDescription of TOP 10 Method: Use data sort and filter functions of EXCEL or other software tools to sort each data from bad to good. Thus facilitate connecting each data ,finding the rules and locating problems more easily.Carry out studying and contrastive analysis on the sub-items statistic function of BSC-level traffic statistic report.If certain important index (such as call drop ratesuccessful handover rate) are found abnormal in BSC-level traffic statistic report, then carry out cell-level traffic statistic to analyze its more detailed content.Check the cells which single index is abnormal and has more absolute times of failure (call dropcongestionhandover failure, etc) .Combine the two parameters, percentage and absolute times of failure (call dropcongestionhandover failure, etc), to decide whether it needs to adopt further measures.

Position And Analyze Problems with Traffic Statistics--Traffic Statistic Analysis General IdeaBSC Level Report

Position And Analyze Problems with Traffic Statistics--Traffic Statistic Analysis General IdeaThe other optimization methodsDTSimulate Subscriber make calls in moving state, Analyze coveragequalityhandoversignaling.CQTmake a great deal of calls in different placeSignaling TraceCollecting signaling through signaling tool or OMCR signaling trace function.

Position And Analyze Problems with Traffic Statistics--Index Analysis Filter MethodEquipment hardware problemsInterference problemsCoverage problemsCommonness ProblemsHandover problemsOther radio parameters problemsIndividuality ProblemsFirst Commonness Second Individuality

Position And Analyze Problems with Traffic StatisticsCommonness factors lead to bad KPIEquipment hardware problemsInterference problemsCoverage problemsOther factors

Position And Analyze Problems with Traffic Statistics Common Problems

Equipment hardware

Interference

Coverage

TCH call drop

Handover

SDCCH / TCH blocking

SDCCH assignment

TCH assignment

Position And Analyze Problems with Traffic Statistics--Common ProblemsEquipment Hardware Problems

Traffic Statistic AnalysisMethod of Position and ResolveThe hardware problems of transmission error code and stability REPEATER self-excitationtower top amplifier yawp etc. .Target cell channel activation NACK or TIMEOUTHigh group link call drop timesSynchronize CLOCKPosition range of hardware problems according to left analysisjudging whether TRX , CMM and TIC problem, whether power of power amplifier too low, combiner, divider, REPEATER problem etc..CELL performance reportSDCCH and TCH usable rate abnormal< 100%High TCH assignment failure rate especially > 10%BTS measurementposition call drop and assignment failure of TRX levelAlarm statistic: find hardware problemsDynamic channel observationcarrier frequency occupying abnormallyNMS measurementSDCCH/TCH channel occupation timeCheck clock problemsMonitor transmission find transmission problems

Position And Analyze Problems with Traffic Statistics--Common ProblemsInterferenceTraffic Statistic AnalysisMethod of Position and ResolveFrequency checkAnalyze inner interference within same or adjacent frequency pointSweep frequency testsearch external interferenceDTCheck interference and signal quality status of the problem section ;Adjust BTSs transmit power of correlative cellsantenna downtilt or frequency point etc. to avoid interference;Enable function of DTXDPC etc. ;Resolve equipment problems (such as: TRX board self-excitationantenna intermodulation). CELL traffic statisticAnalyze interference bands level CS basic measurementAnalyze discipline of interference bands appearschange with time and traffic capacity BTS measurementPosition TRX level interference bands Handover reason measurementThe ratio of UL/DL RQ handover to all handover Cell radio measurementAnalyze level and quality status of cells. Abis interfaces signaling traceAnalyze cells and TRXs with interference.

Position And Analyze Problems with Traffic Statistics-- Common ProblemsCoverage Problems

DT in weak coverage area;Adjust network parameters according to DT result;BTS transmitting power, antenna downtilt and height, Rxlev_ACCESS_MIN_MS, the neighbor relation, RXLEV_ACCESS_MIN of handover candidate cell.Adjust coverage, avoid over-coverageowe-coverage and alone island phenomenon;Add BTS. Cell traffic statistic: Worse UL/DL RQ and KPI; Power control performance measurement: average of UL/DL signal level is too low; Cell radio measurement: Times of low RX-Level have higher percentage; Handover reason measurement: Times of rescue UL/DL Rx-lev handover has higher percentage;Method of Position and ResolveTraffic Statistic Analysis

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisCall Drop TypeRadio Link Failure call dropHandover Failure call dropLAPD call drop

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisAnalysis FrameBSC Level performance reportCELL level performance reportBTS measurementCell radio measurementCELL Level performance reportCS basic measurementAlarm statisticCommon problems analysisIndividuality problems analysisAlarm analysisTraffic statistic analysisSignaling analysisOther optimization methodsFrom whole to particularCarrier frequency levelEasy to position and analyze First commonness then individualityExecute and solve problems12345Solve Call drop problemsConfirm higher call drop cellAnalyze call drop factorsConfirm call drop typeConfirm TRX level call drop

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisCommon causes of call dropHandover parameters setting problemsCoverage ProblemsEquipment hardware problemsInterferenceUL/DL imbalanceSetting of other parameters is irrationalityCall DropCommon Problems already analyzed

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisImproper setting of handover parameters

Traffic Statistic AnalysisResolve MethodsAdd neighbor relation in reason;Adjust handover parameters.

Check handover parameters, find unreasonable parameters setting;Handover common measurement, check handover out failure status;Handover common measurement, check handover reason and percents of each kind of handover;Adjacent cell handover statistic measurement: low success rate of handover out aim at certain cellfind target cell with low handover success rate and looking for cause;CS basic service measurement: handover times/call times 3

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisUL/DL Imbalance (Tower top amplifierHPAAntenna azimuth)Check tower top amplifierCDURDUBTS boards and RF feeder;Check antenna feeder. Check antenna azimuth and downtilt whether according with design criterion; check antenna feeder, jumper feeder is connected rightly and connecters are connected tightly, feeder is undamaged, make sure standing wave rate under normal range.CS basic service measurement: Analyze UL/DL Average_Rx_Lev;Abis interface signaling trace: Analyze UL/DL Rx_Lev;Cell radio measurement: Analyze UL/DL Rx_Lev distributing.

Resolve MethodsTraffic Statistic Analysis

Position And Analyze Problems with Traffic Statistics--Call Drop AnalysisImproper setting of other parametersAmend irrational parameters.

Check radio parameters: adjust irrational parameters;irrational RLT and Rx_lev_Min;Resolve MethodsTraffic Statistic Analysis

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisHandover Analysis Idea

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisGeneral Analysis IdeaCells with handover problems: All cells or individual cell.Handover direction of problem cells : Handover out cell failure or in cell handover failure;Object of handover failure: Between service cell and multi-cell or individual cell.

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisChecking Handover IndexCheck cells with lower handover success rate;Check cells with much handover failure timesAnalyze handover out/in failure times, find out main factors of handover failure;Register out/in cells handover performance;Observe trait of handover failure: For all adjacent cells or individual adjacent cellall conditions or part condition lower handover success rate.

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisPossible Factors influencing Handover Success Rate

Common Problems already analyzedUL/DL ImbalanceEquipment ProblemHandover Parameters IrrationalityCoverageInterferenceLead Low Handover Success Rate

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisImproper setting of handover parametersCheck PBGTrescue handover etc. handover level threshold, setting of handover function switch whether correct.Result of handover times vs TCH call occupation success times is disproportion. If handover/call3Ping-pong handover exist in all probability, should check handover parameters setting and adjust (least time space of inter-cell, PBGT HoLevThs etc.)Cell performance report: Low handover success rate, more handover failure times;BTS measurement: filter TRXs with more handover failure times.Basic measurement: analyze every handover factors percent, PBGT handover percent too high or too low;Handover statistic handover: find out two cells lead to handover failure.Resolve MethodsTraffic Statistic Analysis

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisComprehensive analysisExtend capacity of target cell or traffic proportion;Check hardware;Adjust handover parameters;Optimize adjacent cells;Performance report of cells level: target cell congestion;CS basic measurement: low handover in success rate, maybe handover in cell hardware problems or has interference etc.; Low handover success rate: maybe target cell congestion or handover parameters setting is irrationality;Check neighbor relation: whether have omitted neighbor,single or redundant neighbor; Check exterior cell: setting of exterior cell parameters error.Resolve MethodsTraffic Statistic Analysis

Position And Analyze Problems with Traffic StatisticsHandover Problems AnalysisOther After eliminate commonness problems, optimize parameters of adjacent cells, analyze and resolve UL/DL balance problems of adjacent cells,

Position And Analyze Problems with Traffic Statistics-- Analysis Of TCH BlockingPossible causes of TCH blockingShortage of system capacity or traffic imbalanceData configuration problemInterferenceCoverage problemAntenna and feeder system problemParameters setting problemTCH BlockingCommon Problems already analyzed

Position And Analyze Problems with Traffic Statistics-- Analysis Of TCH BlockingLack of system capacity or unbalanced trafficExtend capacity, or adjust configuration of busy and idle carrier cells;Adjust coverage (adjust transmit power of BTS, antenna azimuth, downtilt, height etc.);Adjust main parameters (CRO, Rxlev_access_Min_MS, enable trafficHo function);Adjust priority level and handover parameters of cells.Too high traffic capacity in TCH (Traffic per channel>0.6)Too much overflow times, system busy for a long time;Traffic imbalance (three cells of one BTS traffic imbalance, or several BTS traffic imbalance;Analyze out serious congestion from performance reports.Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of TCH BlockingAntenna and feeder problemCheck antenna azimuth, downtilt, connection of antenna and feeder system.Frequency point scanning: results to same frequency point through main and secondary diversity antenna measuring;Cell radio measurement: signal level, quality disturbing;Signaling tracing: measurement report analysis.Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of TCH BlockingImproper setting of parametersAdjust irrationality parameters setting;Solve problems.Performance statistics report: judging TCH congestion;Alarm information statisticBTS or TRX problem;BTS measurement: check TRXs;Check parameters: RxLev_Access_Min_MS, cell reselect parameters.Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of SDCCH BlockingCauses of SDCCH blocking

SDCCHParameters problemCapacitySDCCH CongestionInterferenceLAC PartitionCommon Problems already analyzed

Position And Analyze Problems with Traffic Statistics-- Analysis Of SDCCH BlockingImproper setting of parametersAdjust parameters (random access error level threshold, RACH access level threshold), Maximum retransmission times, Extend Transmission distributed timeslots );Adjust location update parameters;Adjust parameters of the dual-band network.Basic measurement: judging reasons for SDCCH congestionRadio access measurement: immediate assignment success times/immediate assignment times>85Parameters checking: parameters of correlative with radio access;Low usability rate SDCCH.Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of SDCCH BlockingInsufficient system capacity

Extend network capacity;Add SDCCH;Adjust T3122T3212RACH parameters etc. Adjust other parameters.Performance report: TCH and SDCCH both congested; Performance report: TCH dont congest but SDCCH is congested seriously; Parameters adjusting: traffic hinge, such as aviation hinge, railway station etc., has lots of location updates;SMS leap.

Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of SDCCH BlockingImproper LAC division

Adjust CRHAdjust cell reselect parametersAdjust T3212Adjust other parameters.Performance report: SDCCH congested badly;Basic measurement: percent of location update too high;LAC partition: business area, LAC areas are crossed badly;Judging MethodSolution

Position And Analyze Problems with Traffic Statistics-- Analysis Of SDCCH BlockingExistence of interferenceCheck and adjust frequency point;Solve interferences;Adjust access parameters.RACH level threshold is lower, at the same time has interference, system mistake for having lots of SDCCH occupation requests.Performance report: SDCCH congested badly;Basic measurement: more useless SDCCH access ;Judging MethodSolution

Position And Analyze Problems with Traffic StatisticsAnalysis of TCH Assignment ProblemsTCH Channel Analysis Process

TCH

Channel Occupation TCH Channel Allocation TCH Channel Assignment

Position And Analyze Problems with Traffic StatisticsAnalysis of TCH Assignment ProblemsCauses of TCH Assignment Failure Hardware problemsTRXCDUloose panel cables Interferenceco-channel/ adjacent-channel interference/ external interference; Antenna problems: damaged antenna feeder, uni-polarized antenna azimuth, inconsistence between down-tilt and antenna type, high VSWR, crossed or misconnected antenna feeders; Unreasonable parameter configurationimproper setting of HF parameters, T3107 value is set too small, inconsistence between data configured at OMCR and the data planned, etc.; Coverage problemweak signal or uplink &downlink imbalance ; Repeater problem: uplink/downlink interference or imbalance of uplink/downlink; Other reasonssoft & hardware versions of the systemsignaling cooperation between BSC and MSC;

Position And Analyze Problems with Traffic StatisticsAnalysis of TCH Assignment ProblemsAnalysis of traffic statisticsJudging MethodSolutionCheck whether radio parameters of the cell is reasonable;Check BERidle interference band level index, decrease radio interference;Check hardware of the cells;Check transmission problems;DT analysis;Check BSC and base station versions to avoid unmatched versions leading to TCH assignment failure.Performance reportfind out cells with TCH assignment failure; Basic measurementsjudge interference bandcall drophandoveruplink& downlink RQ value;Alarm statisticshardware problemsBTS measurementsposition TCH assignment failure of carrier frequency levelNMSjudge whether carrier frequency occupation is normal by occupation time of TCH and SDCCH;Parameter configurationunreasonable dynamic SDCCH parameter configuration.

Cases of Call DropPhenomenon DescriptionOn 16, March, from OMCR BAM statistic, I10 of Station 3 of BSC 80 in PAKTEL network had much more call drop rate suddenly, with its rate more than 7%. Call drop times increased a lot.Problem AnalysisThrough carrying out statistic on detailed performance data, checking call drop types, we found radio link failure accounted for great part of call drop;Through carrying out statistic on the interference band of the cell, we found 3-level or above interference band accounted for higher percentage; We doubted first that the station had interference. After checking frequency planning, we found there was no neighboring interference with adjoining cells. Through BTS measurements, we found the second and third carrier frequency of the station had a higher failure rate From alarm statistics, this station had no hardware alarms, no adjacent cells missed in configuration, handover parameters are reasonable. However, its found that the MAIOs of the second and third TRXs are the same.

Cases of Call DropSolutionAfter adjusting MAIO of the third carrier frequency from 8 to 10, the interference disappeared, call drop times decreased greatly and call drop rate restored to normal.

Cases of TCH Handover Problemsproblem Description Background performance report data show a low success rate of station 1 cell switch. problem Analysis Check the wireless parameters, set reasonable, no problem. Dynamic management background from OMCR found that the district can not be occupied by a carrier frequency. Determine the carrier frequency of a hardware failure, to submit work orders, requiring troubleshooting. Processing fault plates after replacement, indicators improved significantly, the problem solved.

Cases of TCH BlockingPhenomenon DescriptionOn 21, December, we carried out statistic from BAM, and found TCH traffic of the third sector of No. 106 station in BSC8 under Libyan network is very congested suddenly. TCH congestion rateexclude handoverarrived at higher than 30%.Problem AnalysisBefore, this sector wasnt congested, but this time was in sudden TCH traffic congestion. After implementing statistic on the performance report and alarm statistic of the surrounding cells, we found the reason for congestion was that No.127 station corresponding with this cell had broken, thus the neighboring traffic had been absorbed by the third sector of No, 106 station.SolutionAfter coordinating with the office, commission the No.127 station in time. Then TCH traffic congestion of the third sector of N0. 127 had been cleared.

Cases of TCH BlockingA Contrast Before &After Optimization

Cases of SDCCH BlockingPhenomenon DescriptionIn September, after No.61 new station had been commissioned, SDCCH channel of the third cell congested suddenly and its congestion rate was as high as 35%.Problem AnalysisThrough analyzing the basic measurement of the cell, we found the reason for SDCCH congestion in the third cell was that there existed a great amount of positions to be updated. After checking plan data and LAC division, we didnt find unreasonable points. Thus we analyzed that this new station had certain mistaken data during commissioning.SolutionAfter checking, we found LAC No. of the third cell in the station is 8198, while LAC No. of other two cells of the station is 8199. It is confirmed that during commissioning the new station, LAC No. of the third cell was input 8198 mistakenly. It should be 8199. Thus caused a great amount of positions to be updated. Through readjustment, SDCCH congestion rate restored to normal.

Cases of TCH AssignmentPhenomenon DescriptionIn the third cell of No.1 station of PHO, its call drop rate arrives at 6.9% ,successful handover in rate is only 68.38%, while handover out rate is 91.31%.Problem AnalysisTCH assignment rate is morn than 10%, from which we excluded the interference problem and make sure that the cell has hardware problems. After analyzing BTS measurements of the cell, we found that TCH assignment failure rate of the second carrier frequency in the cell is very high, arriving at 30%. And during on-site testing, we found that after occupying this carrier frequency, the signal level is 20dB less than BCCH carrier frequency level.Solution After changing carrier frequency, each parameter restores to normal.

Cases of TCH AssignmentA Contrast Before &After Optimization

**A1BSCChannel Required1A2BSCChannel RequiredSDBSCSDSDCCH1BSCMSImmediate Assignment RejectMST3122*PBGT 50%*

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02 GO_NA09_E1_1 GSM Traffic Statistics Analysis-72