DT KNOWLEGE

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Technical RefreshingPrologueBuild your career with itSTRONGFOUNDATIONPrologueCareer StageBisa karena biasaPrologueCareer StageBisa karena pahamPrologueBisa karena pahamEager to learn continuouslyPrologue

PrologueStrong foundation

Yes, its not the only key. But it gives you flexibility and acceleration to your career trackAdaptiveFast learnerPrologueService Quality

Embrace future opportunityRF GSM & Basic ParameterRF GSM & Basic ParameterHLR/AuCMSC-VLRPacketnetworkPSTNPacketnetworkSS7NetworkSMS-GMSCGrGsEIRBSCBTSUmABSCBTSUmAMSC/GMSCGSM ArchitectureBTS HW ConfigurationPrincipally, BTS similar with a computer

Build from assembledmodular componentBTSCPUBTS HW Configuration

TS 3RF Transmission Principlefrequency ftime tpower 123FDMAPfrequency ftime tpower TS 2TDMAPTS 1Ex: AMPSEx: GSMUm (Air Interface)

UplinkULDownlinkDLMSBTSDL and UL transmitted with different frequencyUm (Air Interface) - FrequencyP-GSM : Primary GSM (GSM900)E-GSM : Enhanced GSM, sedikit tambahan band pada P-GSMR-GSM : Railway GSM, digunakan pada sistem Kereta ApiDCS : Sistem GSM dengan Band baru, 1800 MHz (GSM 1800)876880890GSM90091592192593596017101785180518501880191019301990[MHz]GSM900E-GSME-GSMGSM1800GSM1800GSM1900GSM-RGSM1900Indonesia adopts GSM 900 & GSM 1800Um (Air Interface) - FrequencyC - Radio Frequency Channel (RFC)200 kHzUPLINK (UL)DOWNLINK (DL)Guard band(880) 890 MHz1710 MHz915 MHz1785 MHz(925) 935 MHz1805 MHz960 MHz GSM9001880 MHz GSM1800Duplex distance 45 MHz resp. 95 MHz25 (35) MHz75 MHz25 (35) MHz75 MHzTransmit bandof the Base StationC124(174)374C124'(174')374'C1C2C3C1'C2'C3'Transmit bandof the Mobile StationBCCH: Broadcast Control ChannelFCCH: Frequency Correction ChannelSCH: Synchronisation ChannelPCH: Paging ChannelAGCH: Access Grant ChannelRACH: Random Access ChannelSDCCH: Stand-alone Dedicated Control ChannelSACCH: Slow Associated Control ChannelFACCH: Fast Associated Control ChannelTCH: Traffic ChannelAllocation of signalling channelSignalling MS BTSE for e.g. Call Setup (Authentication, Cipher start, IMEI check,Setup info,..) LUP, SMS,...SignallingTrafficUser DataDLDLULUL + DLDLUL+FCCHSCHPCHAGCHSDCCHSACCHFACCHTCH/FTCH/HFrequency synchronizationTime synchronization + BSIC, TDMA-No.Paging / Searching (MTC)Measurement Report, TA, PC, cell parameters,...Signalling instead of TCH(e.g. for HOV, IMSI Detach, Call Release)BCHBroadcast ChannelCCCHCommon ControlChannelDCCHDedicated ControlChannelUser data Full RateUser data Half RateBCCHCGI, FR/EFR/HR, VAD/DTX, HSCSD,frequency hopping, channel combinationsRACHRequest for signalling channelUm (Air Interface) Logical ChannelMobility Management (MM)MM Idle Mode Behavior

Searching CampingOff

On

MM Cell Selection

Searching CampingOff

OnInitially MS off, then turned on

MS searches for GSM network, selects cell with strongest level, and camps on itMM Cell Reselection

Will do cell reselection based on applied criterion;C1 and C2

MS ONMM C1C1 = Rxlev - RxLevelAccessMin

RxLevRxLevel aktual yang diterima MS di lapangan

RxLevelAccessMinRxLevel minimum yang harus dimiliki MS untuk bisa mengakses cell terkait. Diatur dalam database parameter.

Database parameter& AlgorithmRxLeAccMin valueRxLev actualMM C1C1 = Rxlev - RxLevelAccessMin

Database parameter& AlgorithmRxLeAccMin valueRxLev actualRxLev (actual)RxLevAccMinNo Service Mode(Karena di bawah RxLevAccMin)Service ModeMM C1RxLev (actual)RxLevAccMin = -86 dBm-80 dBmC1 = -80 (-86) = 6

(Service Mode)RxLev (actual)RxLevAccMin = -86 dBm-88 dBmC1 = -88 (-86) = -2 (No Service Mode)MM C1 : RxLevAccMin AdjustmentRxLev (actual)RxLevAccMin = -86 dBm-88 dBmC1 = -88 (-86) = -2 (No Service Mode)RxLev (actual)RxLevAccMin = -90 dBm-88 dBmC1 = -88 (-90) = 2 (Service Mode)MM C2C2 = C1 + CRO

CROCell Reselection Offset

Encourage MS reselect to the desired cell

MS will reselect to the cell with highest C2 value and C1 > 0

Database parameter& AlgorithmRxLeAccMin valueCRORxLev actualC2 & CRO ?MM Idle Mode BehaviorIdle mode behavior adjustment done for some purposes :Increase / decrease coverage(Coverage layering)Traffic/ Load sharingSDSR optimizationMM Dedicated Mode

SMS Send/ ReceiveEx: *888#MOC: Mobile Originating CallMTC : Mobile Terminating CallCell Reselection to a cell in different LAC

Back to Home NetworkMM Dedicated ModeMobility Management at Dedicated mode:HandoverPurposes of HOTo keep a continuous communication with a moving MSTo improve network service performanceTo reduce the call drop rateTo reduce the congestion rateMM Dedicated ModeClassification of HO: Emergency HOTiming Advance (TA) Emergency HOBad quality (BQ) Emergency HO RxLevel_Drop Emergency HOInterference Emergency HO Normal HOEdge HOLayer HOPower Budget (PBGT) HOSpeed-sensitive HO (Fast moving MS HO)MM Dedicated ModeMobility Management at Dedicated mode:Handover

HO SuccessHO SuccessHO FailureHO ConceptMM Dedicated ModeMobility Management at Dedicated mode:Handover

General HO processMeasurement report preprocessingPenalty processingBasic ranking and Secondary ranking HO judgmentMM Dedicated ModeHandover:

Intra cellInter cell

Intra BSCInter BSC

Intra MSCInter MSC

MM Dedicated ModeHandover:

MSC 1MSC 2BSC ABSC BBSC CDRIVE TESTDrive TestDRIVE TESTING HIGHLIGHTSDrive Testing merupakan suatu metode pengukuran dan penilaian wilayah cakupan, kapasitas dan Quality of Service (QoS) dari jaringan radio seluler.Drive testing di perlukan untuk mengetahui gambaran nyata performance network di lapanganDrive TestPlanningImplementationOptimizationDrive Test WorkIn PLANNING works:

Drive Test Before InstallationPerform drive test before our network implemented. This data later will be compare with drive test after implementation, to justify.

Drive Test Before SWAPBefore swap (change operator network), drive testing needed to compare the current network with the network after swap. To justify the new network is better than before.

Drive Test WorkIn Implementation Works:

Drive Test New Site/ Initial Drive TestInitiate the drive test after a site on-air. Make sure that site perform well after on-air. Test Call New SiteConducting tests call at a new On-Air site, to justify the performance of a site just after On-Air.

Drive Test Upgrade/Expand TRXAfter implement new TRX or expand TRX, a drive test performed to justify that site working well with the new TRX.

Drive Test SFH/Hopping implementation After implement SFH/hopping in the network, a drive test performed to justify that this hopping solution working well with the whole network.Drive Test WorkIn Optimization works:

Drive Test Handover/ Add & Delete neighborsDrive test conducted after theres changing in neighbours database. Make sure the add really added and the delete really deleted.

Drive Test before & after DowntiltDowntilt conducting, to get better coverage from each antenna. Drive test performed to make sure the better coverage from each angle changed.

Drive Test Network AuditPerforming drive test activity to maintain the whole network. Could be an annual work. Drive Test Benchmarkperforming drive test to get justification about our network. Can compete or not. With comparing the whole network including 'us in drive test.

Drive Test troubleshootingDrive test for special troubleshooting case. Such as, a site that cannot handover from sites surround it, a site that cannot transmit good signal and cannot achieve its coverage.Drive Test ModeTo see the quality and coverage of the networkTo see the real network performance run, when people callTo see the coverage and idle mode behaviorWhat to See. What to MeasureRxLevelLevel of Received signal strength. In dBm or Steps. If the value in form of step subtracts 110 to the value to get dBm value.

RxLevel is received power level at MS (maximum RxLevel measured by MS is () 40 dBmWhat to See. What to MeasureRxQual

Received signal quality level, measured base on BER (bit error rate). The value is between 0-7, the lower the better.

GoodBadWhat to See. What to MeasureSQIThe parameter used by TEMS to measure Speech Quality. SQI has been designed to cover all factors that RxQual lack to measure. SQI computation considers the factors:

the bit error rate (BER)the frame erasure rate (FER)data on handover eventsstatistics on the distribution of these parameters

GoodBadOthers

CGI

BCCH-BSIC

Hopping

C/I C/AInterference

TATime Advance

What to See. What to Measure

CGI (Cell Global Identity) =What to See. What to Measure

CGI (Cell Global Identity)What to See. What to Measure

510 = Indonesia = Telkomsel --- 11 = XL --- 01 = Indosat --- 89 = HCPT 101 = LAC53601 = Cell IdBCCH ARFCN & BSICWhat to See. What to Measure

BCCH ARFCNAbsolute Radio Frequency Channel Number of Broadcast Control Channel

BSIC = Base Station Identity Code

BSIC = NCC + BCC

NCC (Network Color Code)BCC (Base Station Color Code)NCC = 0 7BCC = 0 .. 7HOPPINGWhat to See. What to Measure

Skema pemancaran dengan frekuensi yang berubah-ubah

Main Purpose : Reduce interference effectFREQUENCY HOPPINGWhat to See. What to MeasureBASEBANDSYNTHESIZERThe BCCH must not hop (FHSYID = 0)N (Hopping Frequencies) N (TRXs)TRX0TRX1TRX2TRX0TRX1TRX2TRX0TRX1TRX2TRX0TRX1TRX2TRX0TRX1TRX2TRX0TRX1TRX2TRX0TRX1TRX2HSN = 1HSN = 2HSN = 3TRX0TRX1TRX2TRX3f B f B f B f B f B f B f B f C f C f C f C f C f C f C TRX3TRX0TRX1TRX2TRX3BCCHBCCHBCCHBCCHBCCHBCCHBCCHBCCHBCCHMAIO = 0MAIO = 1MAIO = 0MAIO = 0MAIO = 1MAIO = 0MAIO = 0MAIO = 1MAIO = 0MAIO = 2MAIO = 3MAIO = 2MAIO = 2MAIO = 3MAIO = 2MAIO = 2MAIO = 3MAIO = 2f A f A f A f A f A f A f A MAIO = 5MAIO = 4MAIO = 4Frequency group: A: 1 4 7 10 13 16B: 2 5 8 11 14 17C: 3 6 9 12 15 18SFH : MAIO & HSNPractice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

C/I and C/ACarrier to Interference ratioInterferenceCo-channelAdjacent Channel12 dB : OK6 dB : OKPractice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

Timing Advance (TA)GSM memakai sistem TDMATransmisi informasi dikirimkan secara urut mulai dariTimeslot 0 .. 1 .. 2 .. 3 .. 4 .. 5 .. 6 .. 7Terkadang user berada di ts 7, Untuk itulah digunakan mekanisme Timing agar ts sampai di BTS dalam keadaan urutPractice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

Timing Advance (TA)GSM memakai sistem TDMADengan mekanisme ini, sekaligus dapat mengetahui jarak antara MS dan BTS.

Hitungan ini didasarkan pada waktu yang dibutuhkan gelombang dari MS sampai ke BTSSecara praktis, cara membaca informasi nilai TA adalah:

TA Value / 2 = Jarak (Dalam Kilometer)Practice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

Typical RF problemCoverage Issue : Low Level, Unstable level, Lack Of dominant server, Fast moving mobile, etc

Quality Issue :Interference, silent call, etc

Practice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

4/10/2015GSM Problem Spot and Recommendation56

Cell ARFCN RxLev C1 C2

Cell A 587 -90 1 41Cell B 58 -65 38 38Cell n1Cell n2

Cell ACell BLow Level Bar Near Site 4/10/2015GSM Problem Spot and Recommendation57

Level Bar Tidak Stabil (Naik-Turun)4/10/2015GSM Problem Spot and Recommendation58

Missing Neighbor Relation Missing Neighbor4/10/2015GSM Problem Spot and Recommendation59Cell ACell BCell n1Cell n2Cell BCell n1Cell n2AB

Non-mutual Neighbor relationNon-mutual Neighbor Relation Cross feeder Case

Practice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

4/10/2015GSM Problem Spot and Recommendation61Non-mutual Neighbor Relation (Missing Neighbor)

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Sample SDCCH analysis in layer 3 messageCongestion Case

Practice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

Call drop due to coverage problem (Bad RxLevel Bad Rxqual)

Call drop Case

Call drop due to interference (Good RxLevel Bad RxQual)

Practice of frequency assignment:example reuse 1x3:

Planning steps:1. Definition of frequency groups A, B , C2. BCCH planning3. Assign groups to sectors4. Assign MAIO to each TRX as shown in slides before5. Assign HSN to each site

4/10/2015GSM Problem Spot and Recommendation64Interference (Co-Channel and Adjacent Channel)Co Channel

Adjacent Channel