Statistics Data Analysis and Optimization_new

8/3/2019 Statistics Data Analysis and Optimization_new

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Statistics Data Analysis

and Optimization V4.0

for HUAWEI GSM/GPRS/EDGE System

Compiled by Jin/Jiangxin

E-mail: [email protected]


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Chapter 1 GSM system

1. Work items in an optimization project2. Review of the GSM system

3. Based technology in GSM system

4. Drive test and analysis

5. Parameters in common use

6. OMCR statistics data and the formula in common use7. Main methods in the performance analysis procedure

8. Selection and reselection

9. SDCCH congestion

10. TCH congestion and drops

11. Call progress introduction in common use12. Power control algorithm

13. Handover algorithm

14. Cases according to statistics data

course contents


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9. SDCCH congestion






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Work items in optimization

Find the problems Statistics data

DT and CQT Alarm check Custom complain

Analysis the problems Statistics analysis DT and analysis Alarm analysis Call process analysis Frequency plan and reuse

Solve the problems Trouble shooting Improve coverage Adjust TRX configuration Adjust antenna system Edit freq.plan table

Neighbor relations Parameters

Checking and compare results Before and after modify Different BSC/Cells Different network

Problems in network Hardware trouble problem

Freq. interfering problem Coverage problem HO relations problem busy or idle problem Traffic balance Underlay and overlay problem KPI Wireless parameter problem Especial problems

(access,roaming,crossed talk,A-interface .)

Steps for problem Find the problems Analysis the problems Resolve the problems

Checking and compare resultsare throughout the optimization process.


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Emphasis of the optimization

System performance

Access

Channel success

Congestion

Drop

Handover

Traffic

Quality

Coverage

Frequency

1. Immediate assignment rate

2. CSSR3. Wireless access rate

4. Sdcch success rate

5. Sdcch congestion rate

6. Sdcch drop call rate

7. Tch success rate

8. Tch congest rate

9. Tch drop call rate(including HO)

10. Tch drop call rate(excluding HO)

11. Ho success rate(from attempt)

12. Ho success rate(from command)

13. SD/TCH traffic14. TCHF and TCHH traffic balance

15. Overlay and underlay traffic balance

16. Coverage rate (DT)

17. BER/MOS


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Optimization flowing(1)

Collect system data

Analysis data and make

optimization plan

Performance data of past week

Engineer parameter table

Freq. plan table

Neighbor list relation (internal and external)

Antenna information

System topology

Customer complain

Make optimization plan, hardware problem list,

DT plan, checkcell health, consistency, frequency,

LAC data, neighbor

Start optimization

Hardware solved and

system testHardware solved and system test

Start optimization meeting


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Output coverage chat,congestion rate,drop

calls,interfering area according to the DT data.

And optimize frequency, adjust channels in the

congestion cells and concentric lay, adj. parameters

Check and optimize the neighbor relation, correct

neighbor data (internal and external neighbors)

Optimize parameters( general)

Put in suggestions and good plan

Optimization summarize and

technology communion

Optimization flowing(2)

Coverage, frequency,

channels, configuration,parameter

Neighbor relations

optimization

Optimize parameters

compare the performance

and put in suggestions

Optimization

summarize


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9. SDCCH congestion






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PSTN Network

Billing Center

GBTS

TE

MT

MS

GBSC

Internet

A

Pb

Um

Gi

GSM network review

HLR/Auc/EIR

SMS-GMSC/IWMSC

MSC/VLR

SS7 Network

GSM Core Network

GGSN

CG

SGSN

DNS

GPRS Backbone

GbGb

Gs

Abis

Um

GPRS Core Network

EDGE PCU

OMC


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Review of BTS3012

DPU: Digital Power Unit

TRU: Transceiver Unit

PMU: Power Monitoring Unit

TMU: Timing/Transmission & Management

Principle for RF send and receive mode:

Send: combining when TRU combined actually

no combining when TRU not combined actually

Receive: dividing receiver when TRU combined

indepandent receiver when TRU no combined


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Access link check

Dual polarizationantenna

TTAoption

Lightning arrester

BTS rack

Jumperconnector(DIN)

DINconnector Lightning arrester/feederconnector(DIN) Jumper/TTA

Connector (DIN)jumper

Jumper/TTAconnector(DIN)

Antenna

Connector(DIN)

FAN BOX

SWITCH BOX

FAN BOX

AIR BOX

AIR BOX

P

S

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TDU

Inside jumper

TRX jumperTX and RDX cables


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9. SDCCH congestion






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Um layer

Communicate MNG(CM)

Radio resource (RR)

Mobility MNG(MM)

CPU

RACH BCCH AGCH/PCH SDCCH SACCH TCH FACCH

TCH0 TCH1 TCH2 ..SACCH ..TCH24 IDL

Multi-frame

Phy. link layer(L1)

Data link layer(L2)

Application layer(L3)


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CM

MM

RR

LAPDm

SigL1

L3

L2

L1

MS

RR BTSMLAPDm

SigL1

LAPD

SigL1

LAPD

SigL1

BTSM

RR

SCCP

MTP

BSSMAP

CM

MM

BSSMAP

SCCP

MTP

MSCBSCBTS

Um AAbis

GSM protocol stake


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Channels

Broadcast control channel

(BCCH)Control channelCommon control channel

(CCCH)

Voice channel

(TCH)

FCH SCH BCCH

(system information)

TCH/FAGCH RACH SDCCH FACCH

SACCH

TCH/H

TCH/9.6FTCH/ 4.8F, HTCH/ 2.4F, H

PCH

Common channel

(CCH)Dedicated channel

(DCH)

Logical channel


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FCCH

SCHBCCH

PCHAGCH

BCCH

CCCH

CommonChannel

SDCCHSACCHFACCHTCH/FTCH/H

DCCH

TCH

DedicatedChannel

PCH AGCH

Downlink CCCH

RACH CCCHCommonChannel

SDCCHSACCHFACCH

TCH/FTCH/H

DCCH

TCH

DedicatedChannelRACH

Uplink CCCH

Downlink and uplink channels


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CCCH configuration

Ccch_conf: ccch blocks in a 51 CCCH-multi-framesWhen one no-combined case:

bs_ag_blks_res: AGCH reserve blocks : 2bs_pa_mfrms: paging blocks : 2

Paging sub-frame: (9-2)*(bs_pa_mfrms)=14

Ccch config Ccch blocks

one combined 3

one no-combined 9

two no-combined 18

three no-combined 27

four no-combined 36

Pch blocks=Ccch blocks-(bs_ag_blks_res),if ccch_config=1 non_combined, bs_ag_blks_res=2, then PCH=9-2=7.

each CCCH 51-multi-frames will be lasted 235.4msPch blocks/sec= Pch blocks/0.2354ms=29.7 blocks/sec

2 times in each Pch blocks for IMSI paging type4 times in each Pch blocks for TMSI paging type

So total paging times/max=Pch blocks/sec*(times in each Pch blocks)


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Search for frequency correction burst

Search for synchronization sequence

Read system information

Listen paging message

Send access burst

Wait for signaling channel allocation

Call setup

Assign traffic channel

ConversationCall release

FCCH

SCH

BCCH

PCH

RACHAGCH

SDCCH

SDCCH

TCH

FACCH

idle mode

off state

dedicatedmode

idle mode

Functions of Channels


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Rxlevel calculation and transmit model

RxLev=EIRP-Path Loss

2, PATH LOSS (predigest formula, need to corrected in project)Okumura/Hata transmission model for 900M macro network.

Lp=69.55+26.16lg (f)-13.82lg (hb)+(44.9-6.55hb)lg (d)-A (hm)Lp: path loss (db)f : frequency (Mhz)hb : BTS antenna height (m)hm : MS antenna height (m)d: distance between MS with BTS

Cost-231/Hata transmission model for 1800 macro network

Lp=69.55+26.16lg(f)-13.82lg(hb)+(44.9-6.55hb)lg(d)-A(hm)-KCost-231/Walfish ikegami model for 900/1800 micro networkKeenan-motley model for 900/1800 indoor distribution system.Planning software for 900/1800 macro system

Path Loss(dB)=k1+k2log(d)+k3Hms+k4log(Hms)+k5log(Heff)+k6log(Heff)log(d)+k7(Diffraction Loss)+Clutter Loss

1, EIRP: efficient power of BTS.

EIRP=10log[P_Forward(mW)-P_Reflected(mW)]+Tx_Antenna_Gain+Rx_Antenna_Gain-Rx_Feeder_Loss P_Forward: power of forward direction(mW) P_Reflected: power of reflected direction(mW) Tx_Antenna_Gain: TX antenna gain of BTS (dbi) Rx_Antenna_Gain: RX antenna gain dbi) Rx_Feeder_Loss: loss of feeder cable


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Down-tilt, height and coverage

tg(B-A/2)=H/RB: down-tiltA: vertical beam widthH: antenna heightR1,2,3: coverage range


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Layers and priorities in dual band network

Background: Traffic increase rapidly

Limited channels in 900 band Frequency re-use more difficult

Quality decrease

More free channels in 1800 band

Offer loose frequency re-use in 1800band

Parameters set: 900 cells offer coverage service (Layer 3)

1800 cells offer traffic service (Layer 2)

MS stay in Layer 2 more (high cell priority)

Set much CRO in 1800 cells

Set easy access parameters in 1800 cells

Set easy handover to 1800 cells

Set 1800 TRU as overlay in concentric HO

Set 900 TRU as underlay in concentric HO


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RLT (DL) and SACCH multi-frame (UL)

Radio_link_timeout (DL,S(T100) )S+2 when MS decode a SACCH multi-frame correctly, S


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Measure reports (MR) and SACCH frame

MS measure the uplink and downlink during the dedication mode.MS/BTS measures and report the uplink/downlink information.The results are prepare for HO, pwr control

A SACCH super-frames is made of 4 SACCH multi-frames.Total 26 frames in one SACCH multi-frame.The MS deals with a full MR in a SACCH super-frames, the period is 480ms(4*120ms),

MS retains the previous MR result of 480ms when it is in the next 480msMS decode the neighbor cellss BSIC in idle frameMS retain MR result for 10s if MS find that a BCCH go out from best 6 neighbor cells

to prevent stopping the MR when HO request is sent to this cell.

Contents in MRActual TA of MSActual tx-pwr of MSThe BA changes indicatorDTX used indicatorThe rx_lev and rx_qual in uplink and downlinkThe rxlev,freq, BSIC of the 6 best neighbors


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Hopping

Frequency

F0

Frame

F1

F2

F3

F4

Time

Hopping algorithm(HSN=0)MAI=(FN+MAIO)mod N, RFCHN=MA(MAI)

FH mode: base-band and RF hoppingMA: hopping frequency, 1*3,1*1 need MA>=2TRXsMAIO: No.of TRX-1HSN: 0-63TSC: BCCFN: 2048*51*26 used in hopping algorithm

N: total of MA in one cell

BCCH channel no hopping (benefit to decode BCCH)SDCCH and TCH channel can hoppingBand hopping and RF hopping

Band hoppingUsing fixed frequency in each TRXUsing different TRX in different timeTCHs in BCCH TRX are hopping (option)MA=TRXsTRX problems Will effect performance

RF hoppingUsing vary frequency in each TRXUsing different TRX in different timeTCHs in BCCH TRX are no hoppingTRX problems will not effect performanceMore common than Band hopping


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Frequency hopping (4*3, 1*3, 1*1)

4*3 hoppingSame frequency as 4*3(MA)

1*3 hopping

Each cell have a MA in same siteSame MA and MAIO in same

direct cells in different sitesBe sure no neighbor-MAIO in same

cell or in the same direct cells.Will get more interfering if theazimuth of sites is not regular

1*1 hoppingEach cell have the same MA in all cellsDifferent MAIO in each cell in one siteSame MAIO in same direct cells in different sites


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Principle of AMR

AMR (Adaptive Multi Rate) is the set of different speech code rate. BTS and MS select and adjustthe appropriate rate according to RQI, so that to improve the MOS quality of network.

system select and adjust to low AMR when RQI is bad (or interfering is high);

System select and adjust to high AMR when RQI is good (or interfering is low)

AMR-FR set (8):12.2k(GSM EFR)/10.2k/7.95k/7.40k(IS-641)/6.70k/5.90k/5.15k/4.75k

AMR-HR set (5):7.40k(IS-641)/6.70k/5.90k/5.15k/4.75k

Benefits to network:

Offer better speech quality: the speech quality isbetter than EFR/HR when system use AMR-FRand AMR-HR whether the interfering is high or low.

Improvement the re-use rate of frequency: theperformance is better when system use the No. offrequency re-use=9(3*3) and 12(4*3) thanN=12(4*3) and 18(6*3), It means that the systemcan offer higher No. of frequency re-use mode inthe condition of the same speech quality.

Improvement the edge coverage. For C/I, AMR-FR4.75k need 3dB while EFR 8dB to keep theFER


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Channel assignment of AMR

Channel assignment principle of AMR

adjust AMR supports according to the busyness type, speech version, circuit pool when BSC receivethe assignment command message which sent from MSCBSC.

Prefer to assign AMR channel if system support AMR.

Prefer to assign common channel if system not support AMR

Parameters for AMR: A interface tag: Phase II+ (BSC32)CIC pool:27 Support FR speech version 1~3

Support HR speech version 1~3 (BSC32)Query TC: support FR/HR speech version 3

Support AMR:AMR switch support active ACS(FR/HR):4 selected rate for AMR-FR, 3 selected rate for AMR-HR AMR start mode: the original AMR rate AMR UL/DL coding rate adj.th1: adjust threshold between 0-1, stet: 0.5db AMR UL/DL coding rate adj.th2: adjust threshold between 1-2, stet: 0.5db AMR UL/DL coding rate adj.th3: adjust threshold between 2-3, stet: 0.5db

AMR UL/DL coding rate adj.hyst1: adjust hysist between 0-1, stet: 0.5db AMR UL/DL coding rate adj. hyst2: adjust t hysist between 1-2, stet: 0.5db AMR UL/DL coding rate adj. hyst3: adjust hysist between 2-3, stet: 0.5db

The parameters need to comply for these items:0 < th[i] < th[i+1] < 63; i = 1, 20 < th[i] + hyst[i] < th[i+1] + hyst[i+1] < 63; i = 1, 2


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Chapter 1 GSM system1. Work items in an optimization project

2. Review of the GSM system






9. SDCCH congestion






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DT analysis and bad coverage/quality

DT analysis itemsCoverage analysis (over CV, less CV, CV confusion, reflection, antenna connection wrong)BER analysis and suggestion

Freq.interfering and C/I,C/A analysis HO analysis frequency HO, HO failure, HO drop)Call setup fail analysisHandover analysisDrop call analysis and suggestionLeak of micro cell and suggestionTA analysisPWR control analysisCQT

DT KPIsRxlev(Full&Sub)Coverage rate

Rxqual(Full&Sub)Call setup success rateDrop call rateHandover Success rateTAPower control level

Reasons of bad coverageVSWR alarm and loss much in downlinkDown-tilt or azimuth is not in reasonStatic power class is too lowBar of the building and the surrounding

Hardware problem or jump cable problemFar distance between sitesWrong neighbor cell relationOver shootingCoverage confusionWrong Antenna connectionsAlone island effectIncorrect parameters

Reasons of bad qualityC/I,C/A interfering (freq.planning)Bad rx_level coverageVSWR and reflective freq.interfering (overlap)Hardware problemParameters of HOTMU and reference clockRF drop call process

Middle frequency interfering


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Crossed cables and Yuanyang Crossed cables

Wrong crossed cablesPlanning azimuth 0/160/260DT azimuth 160/0/260Crossed cables between Cell 16101/16102

Yuanyang crossed cablessame Rxlevel in anywhere along azimuth directionsRxlevel in one direction are better than the other2 TX/RX are connect to Cell 1091(good signal)2 RDX are connect to Cell 1093(bad signal)


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Wrong azimuth or Confused coverage

Wrong azimuth

Planning azimuth 85/170/240DT azimuth 330/220/60Neighbor relationship and frequency

Confused coverageNeed to check azimuth in cell 3201/3203

Need to confirm in every cablesPending? Reflection?Neighbor relationship?


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Wrong location and interfering

Wrong Long/Lati

Planning coverageNeighbor relationshipsFrequency interfering

Channel interfering

Planning coverage and azimuthBad Frequency planWrong coverage against planning


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Overshooting and low coverage

Overshooting and interfering

12km overshootingAdjacent frequency interferingNeighbor relationshipsDrop call

Low coverage

Down-tilt, antenna heightPWR, VSWR, OOS,Surrounding


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Spliter and Combiner problems

Spliter problemThere is a Spliter in cell id =GSP3671Azimuth=40/160no signal of GSP-1 in direction of 40 degreeNo installed Spliter yet

Combiner problemCrossed cables between 3011 and 3012Almost no signal in 3011Rxlevel loss have 30db via the combiner between

GSM and CDMA


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Jump cables or TRX problem in cabinet

Jump cables problem in cabinetTCH allocation always failure in some TRXVery less times in TCH seizure successful timesIncoming handover failure

One TRX OOS in cabinetOne of TRX in a cell have low signal suddenlyThe other TRXs have no problemVSWR alarm or OOS


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OOS and no main service cell

Out of service (OOS)

VSWR-2 alarm?LapD or transmission broken?No power supply?Locked?

No main service cell

Simulate rxlevelNo cell can offer main serviceoffer a main service cellInstall a new main service cell or site


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Wrong CGI in MSC

Wrong CGI in MSCMS cant make any callsAll calls are blockedTCH seizure times for call are 0 timesSupport incoming and outgoing handover


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Drop call analysis

Process of RF drop callsRLT+2 and until to the max_RLT if MS decode SACCH frame correctly ,RLT-1,if MS cant decode SACCH frame ,RLT is decreased to 0 when MS continue un-decoded SACCH frame, RF drop call occurs.uplink is as the same as downlink,the counter SACCH multi-frame.

Main reason of drop calls

interferingBad rx_levhardware problem.RLT, Sacch-multi-frame not correct.TRX Pwr class difference in the same cell.HO drops.Nei cell relations problem.Incorrect HO algorithm and parametersHandover drop callIncorrect PWR control arameter.


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9. SDCCH congestion






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BSC level taskBSC measurement performance

Cell level taskImmediate assignmentSDCCHTCHCongestion

DropHandoverConcentric

Channel capacity and availabilityTRX level task

Path balancedReceived LevelReceived QualityChannel allocationInterfering on idleTiming AdvancedRQI

Other taskA-interface performanceMTP statisticsGPRS/EGPRS resourceFrequency scanGSM cell to cell outgoing/incoming handover

Especial abnormal cell tasks (according users need)

Traffic statistics task introduction


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ChannelsCA300J:Channel Requests (Circuit Service)CA303J:Call Setup Indications (Circuit Service)CA304:Call Setup Indications Timed Out

RA303G:Success Rate of Call Setup (Immediate Assignment)K3006:Configured SDCCHK3004:Traffic Volume on SDCCHK3000:SDCCH Seizure RequestsK3003:Successful SDCCH SeizuresCM30:Call Drops on SDCCHK3001:Failed SDCCH Seizures due to Busy SDCCHK3015:Available TCHsK3016:Configured TCHsCR3027:Mean Number of Available Channels (TCHF)CR3028:Mean Number of Available Channels (TCHH)

K3014:Traffic Volume on TCH (Traffic Channel)K3024:Traffic Volume on TCH (Signaling Channel)Traffic Volume on TCHHK3010A:TCH Seizure Requests (Traffic Channel)K3013A:Successful TCH Seizures (Traffic Channel)K3011A:Failed TCH Seizures due to Busy TCH (Traffic ChannelTotal TCH Call DropsK3022:Call Drops on TCH (Signaling Channel)K3012A:Call Drops on TCH in Stable State (Traffic Channel)K3012B:Call Drops in TCH Handovers (Traffic Channel)CM330:Call Drops on Radio Interface in Stable State (Traffic Channel)CM3300:Call Drops on TCH in Stable State (Error Indication)CM3301:Call Drops on TCH in Stable State (Connection Failure)CM3302:Call Drops on TCH in Stable State (Release Indication)CM331:Call Drops on Radio Interface in Handover State (TrafficChannel)

Cell level statistics items introduction(1)HandoversCH310:Outgoing Internal Inter-Cell Handover RequestsCH311:Outgoing Internal Inter-Cell Handover CommandsCH313:Successful Outgoing Internal Inter-Cell Handover

H312A:Failed Outgoing Internal Inter-Cell Handovers (No Channel Available)CH312C:Failed Outgoing Internal Inter-Cell Handovers (Timer Expired)CH330:Outgoing External Inter-Cell Handover RequestsCH331:Outgoing External Inter-Cell Handover CommandsCH333:Successful Outgoing External Inter-Cell HandoversH332Kc:Failed Outgoing External Inter-Cell Handovers (Handover Request Rejecte(No Radio Resource Available)H332Kf:Failed Outgoing External Inter-Cell Handovers (Handover Request Rejected(Invalid Cell)CH332C:Failed Outgoing External Inter-Cell Handovers (T8 Expired)CH342C:Failed Incoming External Inter-Cell Handovers (Timer Expired)

CH300:Internal Intra-Cell Handover RequestsCH301:Internal Intra-Cell Handover CommandsCH303:Successful Internal Intra-Cell HandoversCH302A:Failed Internal Intra-Cell Handovers (No Channel Available)CH302C:Failed Internal Intra-Cell Handovers (Timer Expiry)CH320:Incoming Internal Inter-Cell Handover RequestsCH321:Incoming Internal Inter-Cell Handover ResponsesCH323:Successful Incoming Internal Inter-Cell HandoversH3229A:Failed Incoming Internal Inter-Cell Handovers (No Channel Available) (TCHH322D:Failed Incoming Internal Inter-Cell Handovers (Reconnection to Old Channel

CH340:Incoming External Inter-Cell Handover RequestsCH341:Incoming External Inter-Cell Handover ResponsesCH343:Successful Incoming External Inter-Cell HandoversH3429A:Failed Incoming External Inter-Cell Handovers (No Channel Available) (TCH3429Ca:Failed Incoming External Inter-Cell Handovers (Timer Expired) (TCH) (TrChannel)


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Cell level statistics items introduction(2)

ConcentricH3001:Internal Intra-Cell Handover Requests (Overlay to Underlay)CH3031:Successful Internal Intra-Cell Handovers (Overlay to Underlay)

R3225K:Failed Handovers from Overlaid Subcell to Underlaid Subcell due to Busy Channels in Underlaid SubcellH3002:Internal Intra-Cell Handover Requests (Underlay to Overlay)CH3032:Successful Internal Intra-Cell Handovers (Underlay to Overlay)R3224K:Failed Handovers from Underlaid Subcell to Overlaid Subcell due to Busy Channels in Overlaid SubcellR3200:Channel Assignment Requests (Underlaid Subcell Only)R3202:Channel Assignment Requests (Underlaid Subcell Preferred)R3202B:TCH Assignment Requests (Underlaid Subcell Preferred)R3201:Channel Assignment Requests (Overlaid Subcell Only)R3203:Channel Assignment Requests (Overlaid Subcell Preferred)R3203B:TCH Assignment Requests (Overlaid Subcell Preferred)CR3557:Traffic Volume of TCHs (Underlaid Subcell)CR3558:Traffic Volume of TCHs (Overlaid Subcell)


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Statistics in Trx level

In common useMean Number of SDCCHs in Interference Band 1-5Mean Number of TCHFs in Interference Band 1-5

Mean Number of TCHHs in Interference Band 1-5Uplink/Downlink Interference Indication Messages (SDCCH)Uplink/Downlink Interference Indication Messages (TCH)Number of MRs (Uplink-and-Downlink Balance Level = 1-11)Number of MRs (TA = 0-63)CR440A:Attempted Immediate AssignmentsCR440B:Successful Immediate AssignmentsR4419A:Attempted Assignments (TCH)R4419B:Completed Assignments (TCH)

CR443A:Attempted HandoversCR443B:Completed HandoversS4350D:Radio Link Failures (SDCCH)S4357D:Radio Link Failures (TCHF)S4358D:Radio Link Failures (TCHH)

Received qualityquality 0=bit error rate 0.00-0.20% (average 0.14%)quality 1=bit error rate 0.20-0.40% (average 0.28%)

quality 2=bit error rate 0.40-0.80% (average 0.57%)quality 3=bit error rate 0.80-1.60% (average 1.13%)quality 4=bit error rate 1.60-3.20% (average 2.26%)quality 5=bit error rate 3.20-6.40% (average 4.53%)quality 6=bit error rate 6.40-12.80% (average 9.05%)quality 7=bit error rate >12.80% (average 18.10%)

Received rxlevelNumber of MRs on uplink/downlink TCHF (receive level

Rank 0-7 receive quality rank 0-7Number of MRs on uplink/downlink TCHH (receive levelRank 0-7 receive quality rank 0-7


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Formulas in common use-1

TCH drop call rate (excluding HO) (%)=

K3022:Call Drops on TCH (Signaling Channel)+K3012A:Call Drops on TCH in Stable State (Traffic Channel)+K3012B:Call Drops in TCH Handovers (Traffic Channel)K3013A:Successful TCH Seizures (Traffic Channel)

TCH congestion rate (include ho)(%)=

K3011A:Failed TCH Seizures due to Busy TCH (Traffic Channel)+CH302A:Failed Internal Intra-Cell Handovers (No Channel Available)+H3229A:Failed Incoming Internal Inter-Cell Handovers (No Channel Available) (TCH)+

H3429A:Failed Incoming External Inter-Cell Handovers (No Channel Available) (TCH)K3010A:TCH Seizure Requests (Traffic Channel)+CH300:Internal Intra-Cell Handover Requests+CH320:Incoming Internal Inter-Cell Handover Requests+CH340:Incoming External Inter-Cell Handover Requests

CA303J:Call Setup Indications (Circuit Service)CA300J:Channel Requests (Circuit Service)

Imm-assignment success rate(%)=

K3022:Call Drops on TCH (Signaling Channel)+K3012A:Call Drops on TCH in Stable State (Traffic Channel)+K3012B:Call Drops in TCH Handovers (Traffic Channel)K3023:Successful TCH Seizures (Signaling Channel)K3013A:Successful TCH Seizures (Traffic Channel)K3013B:Successful TCH Seizures in TCH Handovers (Traffic Channel)

TCH drop call rate (all)(%)=

SDCCH congestion rate (%)= K3001:Failed SDCCH Seizures due to Busy SDCCH

K3000:SDCCH Seizure Requests

SDCCH drop rate (%)= CM30:Call Drops on SDCCHK3003:Successful SDCCH Seizures


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TCH success rate(%)=K3013A:Successful TCH Seizures (Traffic Channel)K3010A:TCH Seizure Requests (Traffic Channel)

Wireless Access success rate(%)= (100%-TCH congesting Rate)X(100%-SDCCH congesting Rate)

Handover outgoing success rate(%)=

CH313:Successful Outgoing Internal Inter-Cell Handover+CH333:Successful Outgoing External Inter-Cell Handovers+CH303:Successful Internal Intra-Cell Handovers

CH310:Outgoing Internal Inter-Cell Handover Requests+CH330:Outgoing External Inter-Cell Handover Requests+CH300:Internal Intra-Cell Handover Requests

Radio outgoing HO success rate(%)=

CH313:Successful Outgoing Internal Inter-Cell Handover+CH333:Successful Outgoing External Inter-Cell Handovers+CH303:Successful Internal Intra-Cell HandoversCH311:Outgoing Internal Inter-Cell Handover Commands+CH331:Outgoing External Inter-Cell Handover Commands+CH300:Internal Intra-Cell Handover Requests

CSSR(%)=

RA303G:Success Rate of Call Setup (Immediate Assignment) *(100%-CM30:Call Drops on SDCCH/K3003:Successful SDCCH Seizures)*(K3013A:Successful TCH Seizures (Traffic Channel)K3010A:TCH Seizure Requests (Traffic Channel)

Formulas in common use-2


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9. SDCCH congestion






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Top 20 worst cells from statistics dataCompositor according to the cell level KPIsSelect the top bad 20(or 10)cells in the main items according to times or rate

Analysis the relative bad KPI itemsSolved the bad cells that affect the BSS level performance resultWorst cells

TOP 20 worst cells and DT method

BSC levelCell level

TRX level

We can resolve the problems fromeasy to difficult step by step.

DT methodAnalysis the coverage rationality

Bad coverage area and bettermentAnalysis the abnormal layer 3 messageInterfering analysisCall setup failure analysisHO parametersPWR control parameters


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Signal analysis method:Signaling analysis method requires engineer master every step and statistic counter.Trace the calls and analysis the signaling informationAnalysis problems in the call-process stepCompare the counters in the call process step and find out the max lost count point.Analysis the every detail call-process stepFind out the problem result

Signalling analysis and compare method

Parameter compare method:Compare the same parameters in different BSCCompare the different results in different parameter valueGet the best parameter results


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6. OMCR statistics data and the formula in common use

7. Main methods in the performance analysis procedure


9. SDCCH congestion






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Boundary model of cells and BA table

HO outgoing

boundary,HO_out

Select boundary,

Reselect

HO Incoming

boundary,HO_in

BCCH neighbor listTransmit insystem information message type 2 in BCCH

In use of select and reselect cells64 cells max

SACCH neighbor listTransmit insystem information message type 5 in SACCHIn use of handover32 cells max

The two tables can be different,but they are almost the same in common use.


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Process of mobile turn on (selection)

MS have not save the present BCCH info. (initial turn on)Scan all the channel and assess the rx_lev in each ARFCN

MS tune to the max rx-levand judge if it is the BCCH

If it is the BCCH ,then MS try to decode the BCCH info.MS select the cell as flowing

Decode info.correctly,and the cell is among the PLMNThe cell is not BARED;C1>0

MS saved the present BCCH info. (When turn off)

MS scan the saved BCCH when turn on the next timeMS select the cell as flowingThe cell is not baredC1>0

Else MS check if there is correct cells in the neighbor list.If there is one,then select the cell as service cellIf there are more,then select the C1/max cellIf there is no,then scan as the case of no BCCH info.


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Cell reselection(C1&C2)

C1= (A - Max. (B, 0))predigest=(Rxlev Average-rxlev_access_min )

thereinto:A=Rxlev Average - rxlev_access_minB= ms_txpwr_max_cch - ms Max allowed power

ms Max allowed power(ms pwr class)ms_txpwr_max_cch(ms pwr class when access)

Reselect principle: (1)C1>0;(2)select C1/max cell

Ms occurs reselect cell in case of any one as below:Downlink failure (DSC=90/bs_pa_mfrms timeout)The cell is bared in BCCHThe C1 of the service cell is < 0 last 5sMs hasnt reselect the cells in the past 15s:

To the same LAC, C1 of neis >present cells 5sTo the different LAC,C1 of neis >present cells value (C1+cell_reselect_hysteresis)Ms not reselection if has reselected in 15s

PT-T=0, H(pt-t)=1T: time from set 6 best

candidate cell to out of 6 cells

C2=C1+CRO-TO*H(pt-t)+CRH (for PT< 31)C2=C1-CRO+CRH (for PT= 31)

MS assess C2 of nei cell and service cell at least 5sIf C2of best nei cell>C2of service cell for 5s,then Ms select cellIf nei cell and service cell are in different LAC,should add CRH


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Other parameters about reselect(1)

CBA:No: normal, Yes: barred

PI:

No: C2 not usedYes: C2 used

PHASE2 MS reselection according to C2PHASE1 MS reselection according to C1

CBQ:No: normalYes: low

CRO: =2*n dBTO: =10*n dBPT: =20*(n+1)sCRH=2*n dB

Cases: PI=0,C2 has no affect (suppose to the same layer)

micro A: C1=35,macro B: C1=45,so micro A: C1 macro B: C2=45, thus MS prefer to reselect A


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9. SDCCH congestion






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SDCCH and Location updateMs will occur location update as follows:

Choose a new LAC cell as the serviceT3212 timeout

ATT(IMSI attach and detach)Roaming location update (inter mobile operators)Choose reasonable parameter with SD congestion cell

Partition LAC in reasonChoose correct parameter about T3212Add SDCCH channelsActive SDCCH dynamic configurationChoose correct C1,CRO,CRH

SDCCH process died (reset BCCH TRX)

MS BTS BSC MSC

Channel_req Channel_Required(2)

Channel_Active(3)

Channel_Active_Ack(4)

IMMEDIATE ASSIGN COMMAND (5)

Establish_IND(Location Updating Req) (6)

CR(Complete_L3)

Location Updating Accepted (10)

TMSI Reallocation Complete (11)

CC

(NOTE 3) Clear_CMD

Clear_CMP

First SABM

SDCCH traffic includes:Call setup (MOC,MTC)Location update

SMSATTCDB (cell database broadcast)

SDCCH dynamic configuration parametersSDCCH dynamic allocation allowed

switch-yes/noIdle SD thrth.

TCH change to SD(for TCH>4 or TRXs)Cell SD maximum

=SD configured +8Tch minimum recovery times

minimum time from TCH to SDCCH and back to TCHIdle TCH thrth N1

When TCH change to SD,it is set a count as ResTIME.And during the period of SD return to TCH,

if idle SD>N1+8, then count-3->0,SD return to TCH

If idle SD


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9. SDCCH congestion






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Reasons of congestion

Reasons of TCH congestionTraffic not balanced between service and neighborsTraffic not balanced between underlay and overlay in concentric

Hardware problem and some TRX OOS.Traffic is more than the capacity.Incorrect coverage areaIncorrect C1,C2 parametersIncorrect HO parametersTransmission problemSDCCH congestion but TCH traffic low

Ways to resolve TCH congestionResolve the hardware and transmission problemTraffic balanced to neighbors or lay with low traffic usageAdjust azimuth and downtilt so that adjust the coverage and trafficAdjust handover hysteresis,C1,C2,control the traffic directionAdjust min DL level on candidate cell in busy cellActive Half-Rate function

Lower TCH traffic busy threshold%Active direct retryLayer and priority-PBGT handoverAllow load handover functionAdd more TCH channels or more TRXBalance the traffic between underlay and overlay


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Normal Cell boundary model

HOoutgoing

boundary,HO_out

Select boundary,

Reselect

HOIncoming

boundary,HO_in

Control traffic by cell boundaryrxlev_access_minC1/C2cell radiusSD/TCH trafficrxlev_access_min SD/TCH trafficcongestion

Min_DL_level_on candidate celldifficult to incoming HOtrafficcongestion

Adjust HO_hysteresisadjust handover boundaryadjust traffic between service cells and neighborsAdjust PGBT HO thrsh. asHO parameter relief congestionAdjust PI, CRO ,PT, TO, CRH,TX_power

Adjust TRXs/channels/cells/sitesActive Half-rate functionOtoU(UtoO) HO Received Level ThresholdMS stay more time in overlay traffic in underlaycongestion in underlay


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Abnormal boundary (-PBGT and pingpong HO)

2-HO to nei cells1-setup

Rselect

HO_out.

Reselect>RHO_outreselect

C1= (A - Max. (B, 0))predigest=(Rxlev Average-rxlev_access_min )Thereinto :

A=Rxlev Average - rxlev_access_minB= ms_txpwr_max_cch - ms Max allowed power(ms pwr class)

1, C1(cell A)-C1(cell B)=RXLEV_BCCH-RXLEV_ACCESS_MIN>02, PBGT(N)=-RXLEV_BCCH >HO_MARGIN , so C1(cell B)-C1(cell A)HO_MARGIN+RXLEV_ACCESS_MIN HO_outHO_MARGIN AB= -5, RXLEV_ACCESS_MIN=5(-105dbm)HO_MARGIN BA=8, RXLEV_ACCESS_MIN=5(-105dbm)To cell A: RXLEV_ACCESS_MIN+HO_MARGIN(5-5)-5-5


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Direct retry and load HO

Cell B

Cell ADR to the nei cells

RHO_outRselect

Sharing the traffic by DR(suggest not allowed)

MS2

MS1

RHO_out

MS1 ho to B

RHO_outload ho thrsh

Load HO

MS1

MS1

Load ho bandLoad HO parameters:

Load ho allowed (original cell and direct cell)System flux thrsh. For load hoLoad ho thrsh.Load req. on candidate cellLoad ho bandwidthLoad ho step periodLoad ho step level

Conditions of Direct Retry functionMS setup in cell A,No more free TCH channels in cell AActive DR in cell A and B

There is free TCH channels in cell B


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TCH drops

Reasons of drop callsInterferingBad rx_lev

Bad rx_qualCoverage confusedHardware problem and VSWRHO dropsNeighbor cell relations and data problem.Antenna physical parameter wrongCrossed feeder cablesWrong jump connect cables wrong in cabinet

RLT, Sacch-multi-frame not correct.Incorrect HO algorithm and parametersTRX PWR class difference in the same cell.Incorrect PWR control parameter.Wrong configuration dataTransmission not in stableTMU version process problem

Radio link not balanced

Drop statistics items for BSC32 (9 items)Unsuccessful TCH seizure (connection failure)Unsuccessful TCH seizure (error indicator)Unsuccessful TCH seizure (internal clear)

Unsuccessful TCH seizure (release indicator)Unsuccessful TCH seizure (EMLPP)Unsuccessful cell internal handover with unsuccessful reversionUnsuccessful BSC internal handover with unsuccessful reversionUnsuccessful outgoing BSC handover with unsuccessful reversionUnsuccessful incoming BSC handover (timeout)

Drop items for BSC6000 (3 summary items)K3022: Call Drops on TCH (Signaling Channel)K3012A: Call Drops on TCH in Stable State (Traffic Channel)K3012B: Call Drops in TCH Handovers (Traffic Channel)

K3022: Call Drops on TCH (Signaling Channel)=[Call Drops on Radio Interface in Stable State (Signaling Channel)] +[Call Drops on Radio Interface in Handover State (Signaling Channel)] +

[Call Drops due to No MRs from MS for a Long Time (Signaling Channel)] +[Call Drops due to Abis Terrestrial Link Failure (Signaling Channel)] +[Call Drops due to Equipment Failure (Signaling Channel)] +[Call Drops due to Forced Handover (Signaling Channel)]

K3012A: Call Drops on TCH in Stable State (Traffic Channel)=[Call Drops on Radio Interface in Stable State (TCH)] +[Call Drops due to No MRs from MS for a Long Time (TCH)] +[Call Drops due to Abis Terrestrial Link Failure (TCH)] +[Call Drops due to Equipment Failure (TCH)] +[Call Drops due to Forced Handover (TCH)]

K3012B: Call Drops in TCH Handovers (Traffic Channel)=[Failed Internal Intra-Cell Handovers (Timer Expired) (TCHF) (Traffic Channel)] +[Failed Internal Intra-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel)] +[Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHF) (Traffic Chann[Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHH) (Traffic Chann[Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHF) (Traffic Channel)][Failed Outgoing External Inter-Cell Handovers (T8 Expired) (TCHH) (Traffic Channel)][Failed Incoming External Inter-Cell Handovers (Timer Expired) (TCH) (Traffic Channe


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9. SDCCH congestion






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3. PAGING REQUEST 2. PAGING COMMAND

MS BTS BSC PCU SGSN MSC/VLR

11'. PAGING12'. PAGING

REQUEST13'. PAGING

REQUEST

A2

4.CHANNEL REQUEST5.CHANNEL REQUIRED

6.CHANNEL ACTIVATION

7. CHANNEL ACKTIVATION

ACKNOWLEDGE

8.IMMEDIATE ASSIGN

CMMAND9. IMMEDIATE

ASSIGNMENT

10. PAGING

RESPONSE

11. EST IND(PAGINGRESPONSE)

C1

A1

B1

1. PAGING

Circuit paging call flowingA1: received circuit paging messages from MSCA2: received circuit paging messages from MSC via G-s interfaceB1: circuit paging command to BTS

Circuit Paging (BSC level)

BTS BSC MSC/VLR

CCCH LOAD INDICATION

A1

OVERLOADB1

CCCH overload call flowingA1: circuit paging PCH overloads of Abis interfaceB1: circuit paging CCCH overloads of Abis interface

A i (BSC l l)


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MS BTS BSC

.ASSIGN CMMAND

A1

MSC

ASSIGNMENT REQUEST

SABM

UA

ESTABLISH INDICATION

ASSIGNMENT COMPLETE

(directly retry)HANDOVER REQIRED

MODE (MODIFY)

MODE (MODIFY) ACKNOLEDGE

(NEGATIVE ACKNOWLEDGE,REJECT)

(directly retry)HANDOVER FAILURE(REQUEST ACKNOWLEDGE)

CHANNEL ACKTIVATION

CHANNEL ACKTIVATION ACKNOWLEDGE

(NACK)

ASSIGNMENT COMPLETE

In Immediate Assignment orIntraBSC Handover

ASS FAILURE

H 4

B 2

B 3B 4B 5

C1

C 2

D1E1

F1

F1

F2

F3

F3

F3

G1

G 2G 3

G4

G6

G5

G5

B6

H 2

H 3

H 3

ASS FAILURE

ASS FAILURE

Assignment (BSC level)

Assignment call processA1: assignment requestsC1-C2: unsuccessful assignments(requested terrestrial resource unavailableE1: unsuccessful assignments(invalid message content)G1-G6: unsuccessful assignments(no radio resource available)B2-B6: unsuccessful assignments(equipment failure)D1: unsuccessful assignments(terrestrial circuit already allocation

F1-F3: unsuccessful assignments(radio interface fail,reversion to the previous channel)H2-H4: unsuccessful assignments(other causes)

O t i BSC h d (BSC l l)


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MS BSC2BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER REQUEST

HANDOVER REQ ACK

HANDOVER COMMAND

HANDOVER COMMAND

MS

HANDOVER ACCESSHANDOVER DETECT

HANDOVER COMPLETEHANDOVER COMPLETE

CLEAR COMMAND

CLEAR COMPLETE

A1

B1

C1

D1 , E1, F1

Outgoing BSC handover (BSC level)

Attempt outgoing BSC handoversA1: attempt outgoing BSC handoversB1: attempt outgoing BSC handovers (from 900)C1: attempt outgoing BSC handovers (from 1800)D1: outgoing BSC handoversE1: outgoing BSC handovers (900->1800)F1: outgoing BSC handovers (1800->900)

MS BSC2BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER REQUEST

HANDOVER REQ ACK

HANDOVER COMMAND

HANDOVER COMMAND

HANDOVER DETECT

HANDOVER COMPLETE

CLEAR COMPLETE

A1, B1, C1 , D1, E1

CLEAR COMMAND

Successful outgoing BSC handoversA1: successful outgoing BSC handoversB1: successful outgoing BSC handovers (from 900 to 900)C1: successful outgoing BSC handovers (from 1800 to 1800)D1: successful outgoing BSC handovers (900->1800)E1: successful outgoing BSC handovers (1800->900)

BTS BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER COMMAND

CLEAR COMMAND

CLEAR COMPLETE

A1

HANDOVER FAILURE

HANDOVER FAILURE

CLEAR COMMAND

CONN FAIL IND

ERROR INDICATION

HANDOVER COMMAND

B1

B2

B3

Unsuccessful outgoing BSC handoversA1: unsuccessful outgoing BSC handovers with successful reversionB1-B3: unsuccessful outgoing BSC handovers with unsuccessful reversion


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Incoming BSC HO (BSC level)

Unsuccessful incoming BSC handoversA1-A5 : unsuccessful incoming BSC handoversB1-B2: unsuccessful incoming BSC handovers(equipment failure)C1-C3: unsuccessful incoming BSC handovers (other causes)D1 : unsuccessful channel activation in incoming BSC handovers(NACK)

Successful Incoming BSC handoversA1: successful incoming BSC handoversB1: successful incoming BSC handovers(900->1800)C1: successful incoming BSC handovers(1800-900)D1: successful incoming BSC handovers(900 to 900)

E1: successful incoming BSC handovers 1800to 1800)F1: attempt incoming BSC handovers

I di t i t ( ll l l)


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MS BTS BSC

CHANNEL REQUEST

CHANNEL REQUIRED

CHANNEL ACTIVATION

CHANNEL ACTIVATION ACKNOWLEDGE

IMMEDIATE ASSIGN CMMAND

SD-ATT-C1TCH-ATT-C1TCH-ATT-BSC1SD-ATT-BSC1TCH-ATT-C 6

TCH-ATT-C 7

TCH-SUCC-C 6TCH-SUCC-C 1

TCH-ATT-C 62TCH-ATT-C 61

SD-SUCC-C 1

EST_IND

SD-SUCC-C4Immediate assignment processSD-ATT-C1: attempted SDCCH seizures(all)

TCH -ATT-C1: attempted TCH seizures(all)TCH -ATT-C6: attempted TCH seizures for very early assignmentTCH -ATT-C7: attempted TCH seizures for SDCCH overflowSD-SUCC-C1: successful SDCCH seizures(all)SD-SUCC-C4: successful SDCCH seizures for immediate assignmentTCH -SUCC-C6: successful TCH seizures for very early assignmentTCH -SUCC-C1: successful TCH seizures(all)

TCH -SUCC-C61: successful TCH allocation for very early assignmentTCH -SUCC-C62: successful TCH allocation for SDCCH overflow

Immediate assignment (cell level)

A ig t ( ll l l)


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MS BTS BSC

.ASSIGN CMMAND

MSC

ASSIGNMENT REQUEST

SABM

UA


ASSIGNMENT COMPLETE

(directly retry)HANDOVER REQIRED

(directly retry)HANDOVER REQUEST ACK

CHANNEL ACTIVATION

CHANNEL ACTIVATION ACK

TCH-ATT-C 2TCH-ATT-C 8TCH-ATT-C 9

TCH-ATT-C 10TCH-ATT-C 5

TCH-ATT-C13

TCH-ATT-C14QUEUEING INDICATION

TCH-ATT-C16

TCH-ATT-BSC 2

TCH-SUCC-C23

TCH-SUCC-C21,22

TCH-SUCC-C51,54,55,56

TCH-SUCC-C52,53,54,55,56TCH-SUCC-C82,83

TCH-SUCC-C81TCH-SUCC-C91TCH-SUCC-C101

TCH-SUCC-C92,93TCH-SUCC-C102,103

TCH-SUCC-C13

TCH -ATT-C2: attempted TCH seizures(all)

TCH -ATT-C5: attempted TCH seizures for callTCH -ATT-C8: attempted TCH seizures for MOCTCH -ATT-C9: attempted TCH seizures for MTCTCH -ATT-C10: attempted TCH seizures for call-reestablishTCH -ATT-C13: attempted TCH seizures for directed retryTCH -ATT-C14: TCH queue requestsTCH -ATT-C16: TCH preemption

TCH -SUCC-C21--23: successful TCH seizures(all)

TCH -SUCC-C51--53: successful TCH seizures for callTCH -SUCC-C81--83: successful TCH seizures for MOCTCH -SUCC-C91--93: successful TCH seizures for MTCTCH -SUCC-C101--103: successful TCH seizures for call-reestablishTCH -SUCC-C13: successful TCH for directed retryTCH -SUCC-C54: successful assignments of speech v1 TCHTCH -SUCC-C55: successful assignments of speech v2 TCHTCH -SUCC-C56: successful assignments of speech v3 TCH

Assignment (cell level)

TCH call drop (cell le el)


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MS BTS BSC

.ASSIGN CMMAND

MSC

ASSIGNMENT REQUEST

SABM

UA


CHANNEL ACTICATION

CHANNEL ACTIVATION ACK

A1

ERROR INDICATION

CONNECTION FAILURE INDICATION

A2

TCH call drop (cell level)

Call drop processA1: TCH call drop (error indication)A2: TCH call drop (connection failure)

I t l i t ll HO


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MS BTS' BSC Ori-Cell

HANDOVER ACCESS

UA

Intercell Handover Request

TCH-ATT-C11

BSC Des-Cell BTS''

MRHandover algorithm

HANDOVER COMMAND

Intercell Handover Response

HANDOVER DETECT

CH ACT

CH ACT ACK

HANDOVER COMPLETE

Inter Clear Request

(Handover Success)

TCH-ATT-BSC3SD-ATT-BSC2TCH-ATT-C17TCH-ATT-C3

TCH-SUCC-C17TCH-SUCC-C3

SD-SUCC-C2

SD-ATT-C2

SABMTCH-SUCC-C11

Internal inter cell HO

Internal inter cell handovers

SD-ATT-C2: attempted SDCCH seizures(all)TCH -ATT-C3: attempted TCH seizures(all)TCH -ATT-C11: attempted TCH seizures for intraBSC incoming cell handoverTCH -ATT-C17: attempted TCH seizures for intracell handoverTCH -SUCC-C17 : successful TCH seizures for intracell handoverTCH -SUCC-C3: successful TCH seizures(all)TCH -SUCC-C11: successful TCH seizures for intraBSC incoming cell handoverSD-SUCC-C2: successful SDCCH seizures for handover,

successful SDCCH seizures(all)

MS BTS BSC MSC/VLR

HANDOVER COMPLETE

HANDOVER COMMAND

A1, B1, C1, D1, E1

ASSIGNMENT REQUEST

ASSIGNMENT COMPLETE

MS BTS BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER COMMAND

HANDOVER PERFORMED

A1, B1 , C1, D1, E1, F1

Non_DR incoming inter cell HO in BSC(simulate with SDCCH handoveA1: successful intracell handoversB1: successful incoming internal intercell handoversC1: successful incoming internal intercell handovers (from900)D1: successful incoming internal intercell handovers (from1800)E1: successful dual-band intercell handoversF1: successful incoming internal intercell handovers

successful incoming interBSC intercell handovers

DR incoming inter cell HO in BSC(simulate with SDCCH handover)A1: successful TCH seizures for intraBSC incoming cell handoverB1: successful incoming internal intercell handovers (from900)C1: successful incoming internal intercell handovers (from1800)D1: successful dual-band intercell handoversE1: successful incoming internal intercell handovers

Internal inter cell HO fail re


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MS BTS BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER COMMAND

HANDOVER PERFORMED

CONN FAIL IND

A1 , B1

New Channel

ERROR IND

Old Channel

CHANNEL ACT

CHAN ACT ACK

HANDOVER DETECTIOIN

CHAN ACT NACKA4

CONN FAIL IND

A2, B2

CONN FAIL INDA3 , B3

A5, B4

ERROR INDA6 , B5

ERROR INDA7 , B6

New Channel

incoming internal inter cell HO failure

A1-A7: unsuccessful incoming internal inter cell handoversB1-B6: unsuccessful incoming internal inter cell handovers(other causes)

Internal inter cell HO failure

MS BTS BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER COMMAND

HANDOVER PERFORMED

CONN FAIL IND

New Channel

ERROR IND

Old Channel

CHANNEL ACT

A1 , F2

CONN FAIL INDA2, F3, H1,J1

A4, F4

ERROR INDA5, F5, H2, J2

.HANDOVER FAILURE

A3, B1, C1, D1, E1, F1, G1, I1

CLEAR COMMAND

A6, F6

CLEAR COMMAND

A7, F7Old Channel

Outgoing internal inter cell HO failureA1-A7: unsuccessful outgoing internal intercell handoversB1: unsuccessful outgoing internal intercell handovers (channel mode unacceptable)C1: unsuccessful outgoing internal intercell handovers (TA out of rage)D1: unsuccessful outgoing internal intercell handovers (freq. not implemented)E1: unsuccessful outgoing internal intercell handovers (timer expired)

F1-F7: unsuccessful outgoing internal intercell handovers (other causes)G1: unsuccessful internal intercell handovers with successful reversionH1-H2: unsuccessful internal intercell handovers with unsuccessful reversionI1: unsuccessful outging cell handovers with successful reversionJ1-J2: unsuccessful outging cell handovers with unsuccessful reversion

Outgoing interBSC inter cell HO


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MS BSC2BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER REQUEST

HANDOVER REQ ACK

HANDOVER COMMAND

HANDOVER COMMAND

MS

HANDOVER ACCESSHANDOVER DETECT

HANDOVER COMPLETEHANDOVER COMPLETE

CLEAR COMMAND

CLEAR COMPLETE

A1

B1 , C1, D1, E1, F1

HANDOVER REQUIRED

HANDOVER REQUEST

HANDOVER REQ ACK

Outgoing interBSC inter cell HO

outgoing Inter bss inter cell HO attemptedA1: attempt outgoing interBSC intercell handoversB1: inter BSC outgoing cell handoversC1: outgoing interBSC inter cell handovers(to900cell)D1: outgoing interBSC inter cell handovers(to900cell)E1: successful dual-band intercell handoversF1: attempted outgoing intercell handovers(12 causes)

MS BSC2BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER REQUEST

HANDOVER REQ ACK

HANDOVER COMMAND

HANDOVER COMMAND

HANDOVER DETECT

HANDOVER COMPLETE

CLEAR COMPLETE

A1, B1, C1, D1, E1

CLEAR COMMAND

outgoing Inter bss inter cell HO successfulA1: successful outgoing interBSC intercell handoversB1: successful outgoing interBSC inter cell handovers(to900cell)C1: successful outgoing interBSC inter cell handovers(to900cell)D1: successful dual-band intercell handoversE1: successful outgoing intercell handovers(12 causes)

BTS BSC1 MSC/VLR

HANDOVER REQUIRED

HANDOVER COMMAND

CLEAR COMMAND

CLEAR COMPLETE

A1, C1

HANDOVER FAILURE

HANDOVER FAILURE

CLEAR COMMAND

CONN FAIL IND

ERROR INDICATION

HANDOVER COMMAND

B1 , D1

B2 , D2

B3 , D3

inter bss outgling handover failure

A1: unsuccessful outgoing BSC handovers with successful reversionB1-B3: unsuccessful outgoing BSC handovers with successful reversionC1: unsuccessful outgoing cell handovers with successful reversionD1-D3: unsuccessful outgoing cell handovers with unsuccessful reversion

Incoming interBSS inter cell HO


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MS Other BSC

HANDOVER ACCESS

UA

HANDOVER REQUIRED

TCH-ATT-C12

HUAWEI BSC HUAWEI BTS

HANDOVER COMMAND

HANDOVER REQUEST ACK

HANDOVER DETECT

CH ACT

CH ACT ACK

HANDOVER COMPLETE

TCH-ATT-BSC4SD-ATT-BSC3

MSC

TCH-ATT-C15 QUEUEING INDICATION

TCH-ATT-C4

TCH-SUCC-C4TCH-SUCC-C12

SD-SUCC-C3

SD-ATT-C3

SABM

HANDOVER REQUEST

Incoming interbsc inter cell HOSD-ATT-C3: attempted SDCCH seizures(all)TCH -ATT-C4: attempted TCH seizures(all)TCH -ATT-C12: attempted TCH seizures for inter bsc incoming handoversTCH -SUCC-C4: successful TCH seizures(all)TCH -SUCC-C12: successful TCH seizures for inter bsc incoming handoverSD -SUCC-C3: successful SDCCH seizures for handover

successful SDCCH seizures for(all)

Incoming interBSS inter cell HOMS BTS BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER DETECTION

A1, B1, C1

CHANNEL ACT

CHAN ACT ACK

HANDOVER COMPLETE

HANDOVER REQ ACK

HANDOVER REQUESTT

incoming inter bss HO Success

A1: successful incoming inter bsc inter cell handoverB1: successful dual-band intercell handovers

C1: successful incoming intercell handovers

MS BTS New BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER COMMAND

HANDOVER COMPLETE

Old Channel

CONN FAIL IND

HANDOVER DETECTION

A1

New Channel

HANDOVER REQUEST

Old BSC

HANDOVER REQUIRED

CHAN ACT

CHAN ACT ACK

CHAN ACT NACK

New Channel

A2

CLEAR COMMAND

CLEAR COMMAND

CLEAR COMMAND

A3

A4

A5

A3

HANDOVER REQ ACKHANDOVER COMMAND

inter bss incoming handover failure

A1-A5 : inter bsc incoming cell handovers

Intracell HO


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MS BTS BSC MSC/VLR

HANDOVER COMPLETE

HANDOVER COMMAND

A1

(Intracell handover)

HANDOVER PERFORMED

Intracell ho successA1: successful intracell handovers

MS BTS BSC MSC/VLR

HANDOVER COMPLETE

.HANDOVER COMMAND

A2

(Intracell handover)

HANDOVER PERFORMED

CONN FAIL IND

Old Channel

CONN FAIL IND

HANDOVER FAILURE

A3

A1

Old Channel

New Channel

A5

CLEAR COMMAND

CLEAR COMMAND

A4

ERROR IND

A6

ERROR IND

A7

Intracell ho failureA1-A7: unsuccessful intracell handovers

Intracell HO


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9. SDCCH congestion


11. Call progress introduction in common use

12. Power control algorithm



MR pre-processing and voting


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MR pre-processing Each MR has a serial number. the network will fill up MR according to interpolation algorithm. When

the serial numbers are discontinuous (some MRs missing). The simple interpolation algorithm is linearity interpolation according the previous and the later MRs

when missing MRs occur. Calculate average results of several consecutive MRs to obtain current information, reduce the

influence of some abnormal MR for judgment of PWC or HO. The relation parameters: allowed MR numbers lost, filter length

MR pre-processing and voting

MR MR MRMR MR MR

Consecutive MR flow

Filter length

MR MRMR MR

N

Consecutive MR flow

Interpolation m missing MR

N+1 N+m+1 N+m+2

MR

MR voting (N/P) for GSM0508 protocol

N(N1-N8): MR numbers used to voting process in PC and HOP(P1-P8): MR numbers exceeded voting threshold in PC and HO,The process will be performed when the numbers of P over the threshold in N.Parameters relation to PWR control: P1-4/N1-4Parameters relation to HO: P5-8/N5-8P/N5-8 >P/N1-4

When the rxqual or rxlev is not good ,the system try to adjust PWC before HO

Power Control Overview


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Process of power control commands

It takes 3 measurement report periods(3*480ms) from commandsending to execution.

SA0 SA1A0 SA0A1A1 SA2A2A2 SA3A3A3

BTS sends the command

for power control and TA

in SACCH header.

MS obtains

SACCH block

MS begins to send the

measurement report of the

last multi-frame.

In the 26 multi-

frames, frame 12

sends SACCH.

BTS receives the

measurement report

SACCCH report period:

26X4=104 frames (480ms)

MS adopts the new

power level and TA

MS begins to set up a new SACCH

header to report the new TA andpower control message.

Power Control Overview

PWC algorithm overview


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Huawei PC algorithm: HW I and HW II power control

Measurement reportpre-processing

Power control algorithmselection

Yes

HW I power control

algorithm

HW II power control

algorithm

GSM0508 power control

Algorithm (ordinary)

PWC algorithm overview

Parameters of ordinary PWR control window


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Parameters of ordinary PWR control window

MS: uplinkUL PC allowedRx-lev thrsh.for UL increase=20(-90)

N1/P1Rx_lev thrsh.for UL decrease=40(-70)N2/P2Rx_qual thrsh.for UL increase=5N3/P3Rx_qual thrsh.for UL decrease=1N4/P4

BTS: downlinkDL PC allowedRx-lev thrsh.for DL increase=20(-90)

Rx_lev thrsh.for DL decrease=40(-70)Rx_qual thrsh.for DL increase=5Rx_qual thrsh.for DL decrease=1PC period

MS(uplink) are independence correspondingly and the PWC is rapidGoal: adjust MS tx pwr to let BTS receive stable signal, reduce the uplinkinterference, reduce power of MS.

BTS(downlink) is relations all the MS in this cell and the PWC is slow.Goal: adjust BTS tx pwr to let MS receive stable signal, reduce the downlinkinterference, reduce power of BTS

So it mainly means UL PWC in the Power Control process on this hand.

Ordinary PWC window


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-110 -110

MS(UL):Rx_lev thrsh.for UL decrease=40(-70)

Rx-lev thrsh.for UL increase=20(-90)

BTS(DL):Rx_lev thrsh.for DL decrease=40(-70)

Rx_lev thrsh.for DL increase=20(-80)

-80

-100

-70

-90

-80

-100

-70

-90

Rx_qual thrsh.for UL decrease=1

Rx_qual thrsh.for DL decrease=1

Rx_qual thrsh.for UL increase=5

Rx_qual thrsh.for DL increase=5

0

BER

2

4

6

7

0.14%(0-0.2%)

0.57%(0.4-0.8%)

2.26%(1.6-3.2%)

9.05%(6.4-12.8%)

18.10%(>12.8%)

grade

1 0.28%(0.2-0.4%)

3 1.13%(0.8-1.6%)

5 4.53%(3.2-6.4%)

Ordinary PWC window

Huawei I PWC algorithm (average PWC)


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The adjust value

=(DL/ul rx_lev expected current dl/ul rx_lev) * DL /ul rx_lev compensation

+[current dl/ul rx_qual DL/ul rx_qual expected]*10* DL/ul rx_qual compensation

The adjust value UL edge hoUL RX_LEV CompensationUL Qual. ExpectedUL Qual. CompensationMAX PWC Step

PWC IntervalMS PWC Period

Filter Length for Initial RX_LEVFilter Length for Stable RX_LEVFilter Length for Qual.Power Increment after HO Fail.

BTS: downlinkDL RX_LEV ExpectedDL RX_LEV Compensation

DL Qual. ExpectedDL Qual. CompensationMAX PWC Step

BTS PWC PeriodFilter Length for DL RX_LEVFilter Length for DL Qual.

Huawei II PWC algorithm (self-adapt PWC)


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Huawei II PWC algorithm (self adapt PWC)

Lack of huawei I PWC algorithm:Average PWC algorithm has a delay when system analysis the MRs ,so system cant adjust rapidly.System only analysis the past MR results and cant expected the PC direct well.

Exit the oscillate cases when the PWC process is near to the expected value.

Huawei II PWC algorithm:Adjust the LEV PWC direct in vary LEV value by comparing expected and current value.Adjust the QUAL PWC direct in fixed QUAL value by comparing expected and current valueAssess the final PWC direct and PWC value by calculating LEV PWC and QUAL PWC synthetically.When the PWC direction is the same ,the PWC value take the more value

When the PWC direction is opposition , the PWC is preferred to the value of PWC by LEV.

PC by lev PC by qual PC by lev and qual

AdjStep_Lev AdjStep_Qul max(AdjStep_Lev,AdjStep_Qul) AdjStep_Lev AdjStep_Qul No action AdjStep_Lev No action AdjStep_LevAdjStep_Lev AdjStep_Qul AdjStep_LevAdjStep_Lev AdjStep_Qul max(AdjStep_Lev,AdjStep_Qul)AdjStep_Lev No action AdjStep_Lev

No action AdjStep_Qul AdjStep_QulNo action AdjStep_Qul AdjStep_QulNo action No action No action

Huawei II PWC algorithm (PWC direct and value)


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Huawei II PWC algorithm (PWC direct and value)

Adj. step_lev in UL: UL rx_levUL rx_lev upper thrsh., MS decrease pwr.adj. step_lev=ul rx_lev - (UL rx_lev lower thrsh. +UL rx_lev upper thrsh.)/2

UL rx_lev lower thrsh < UL rx_lev


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9. SDCCH congestion






Summary and classification of HO


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Summary and classification of HO

Summary of HOHO can decrease drop calls and relief congestion when MS is movingMs report best 6 neighbor cells in MR and BSS votes whether HO occurs and direct nei cell

System sends handover command message ,and start HO process.inside shows AFRCN,TS,BCCH,BSIC,PC level,TSC,HO cause, sync/Async about the direct cell.MS send handover complete in the direct cell if MS handovers to direct cell successfully.When MS HO to direct cell unsuccessfully,

if ms reverse to the source cell successfully,ms sent HO failure message to systemelse if reverse unsuccessfully when the timer is timeout, HO call drop occurs in this case.

The message assignment command/complete is used in intra-cell HOs.

Classification of HO Emergency HO

Timing Advance (TA) Emergency HO Bad quality (BQ) Emergency HO Rx_Level_Drop Emergency HO

Interference Emergency HO Load HO Normal HO

Edge HO Layer HO Power Budget (PBGT) HO

Speed-sensitive HO (Fast moving MS HO) Concentric Cell HO

Priority level of HO


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Priority level of HO

M.R.

preprocessing

Penaltyprocessing

Basic ranking

Secondaryranking

HO voting

emergency HO

TA

bad quality(BQ)rapid lev decrease

interfering

Load Sharing HO

normal HOEdge

layer

PBGT

Processingprogram

OMC forced HO

Directed retry

Overlaid/underlaid HO

Fast moving MSHO

HO penalty and ranking rules


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HO penalty process (second step of HO algorithm process ) Penalty on the target cell when a HO fails.

avoid to the ms select this cell again in the next HO voting process.

Penalty on the original serving cell when an emergency HO ( base on BQ and TA ) is performed.avoid MS to be handed back to the BQ&TA cell again within penalty time.

Penalty on other high priority layer cells after a fast moving HO is performed.avoid MS to be handed back to the high priority layer again within certain time(layer priority grade is 4).

A new HO attempt is prohibited within the penalty time after an overlaid/underlaid HO fails.

O pe a ty a d a g u es

Ranking rules

M rule for ranking neighbor cellsit can be put into the candidate cell list only if the cells comply for following conditions.To service cell: Rx_lev(s)rxlev access min(s)-MAX(0,Pa(s)) > 0

Pa(0) =ms_txpwr_max_ccch(s) ms_max_allowed_pwr(s)To nei cell: Rx_lev(n)rxlev access min(n)-max(0,Pa(n))min_access_level_offset(n)>0

K rule for ranking neighbor cellsSort the result cells in descending order by rxlev according to M rule cells.

16bits rule for ranking cells:Both the serving cell and the neighbor cells have their own 16bits value.The smaller the value is, the higher the priority and position the cell is in the cell list.

Basic/Secondary Ranking(16 bit rule)


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y g( )

12345678910111213141516

The 6 strongest cell and

service cell rx_lev bit

000-110 and the strongest

cell value is 000

Intercell ho hysteresis bit

Service cell=0

Rx_lev(n)>rx_lev(s)+ho hys. Set 0

else Set 1

Compare intercell_ho_hysteresis andPBGT thrsh. The higher value is

effective in the HO type

Layer and cell priority bit

4 layers and 16 cell priority/layer=64

Pico is highest and umbrella is lowest.

If rx_lev(s/n) is lower than inter_layer_ho_thrsh.

and inter_layer_ho_hysteresis the bits are set 0

Load sharing bit

Load(s)>load ho thrsh. Is set 1 else 0

Means if it is load busy ,it is put a low

part in the nei list

Co_BSC/MSC bit

Service cell =0

If nei cells and S_cell are in co_BSC/MSC,

value is set 0 else 1

If rx_lev(s/n) is lower than inter_layer_ho_thrsh.and inter_layer_ho_hysteresis the bits are set 0

If co_BSC/MSC is not allowed the value is set 0.

Cell type bit

Internal =0

external-=1

Inter layer ho thrsh. Bit

Rx_lev(s)>=inter layer ho thrsh.-inter layer ho hysteresis

is set o, and 13,12,10-5 are set 0 ,Else set 1

Rx_lev(n)>= inter layer ho thrsh.+inter layer ho hysteresis

is set o, and 13,12,10-5 are set 0 ,Else set 1

Reserve bit

Emergency HO and load HO voting


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g y g

Emergency HO voting TA HO criterion :

TA of the serving cell > TA Thrsh.

BQ HO criterion :Uplink quality > UL Qual. ThrshDownlink quality > DL Qual. Thrsh.

Rx_Level_Drop HO:C1(nt)=A1C(nt)A2C(nt-t)A8C(nt-7t)C (nt) is the uplink RX_Level of the serving cell in the MR received at the time of "nt".Filter A1A8=value-10(A1++A8=80)

Filter B=compare valueIf C1(nt)B and C(nt)is below edge ho edge_rx_lev thrsh, it is considered as RLD.

Interference HO (DL&UL) :rx_lev>rxlev thrsh.for interf. HO

rx_qualrxqual thrsh for interf. HO.

Load HO votingCell Load HO Criterions :

System load of BSC < system flux thrsh. for loadHO load > load HO thrsh.

Load of target cell < load HO threshold

Normal HO, fast moving HO and concentric HO voting


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, g g

Normal HO voting Edge HO Criterion:

Rx_lev inter layer ho thrsh. + inter layer ho hysteresis.And target cell priority should be higher than the serving cells.

PBGT HO Criterions :PBGT(n)>PBGT ho thrsh. In N/PPBGT(n)=Scell[Min(ms txpwr max ccch,ms max allowed pwr)rxlev dl-PWR_C_D]

Ncell[Min(ms txpwr max ccch,ms max allowed pwr)rxlev dl(n)]

Fast moving HO votingWhen the serving cell is micro cell : MS moves the ms fast-moving valid cells (Q) in ms fast-moving watch cells (P>=Q)

within MS Fast_Moving Time Thrsh. MS moving time=2Radius/Velocity =TA threshold + TA hysteresisOr Rx_lev


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9. SDCCH congestion






Congestion, interfering and TRX


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g , g

Problems: Interfering in PTCSCU-2(interfering level:-60~-80dBm), can not absorb any traffic PTCIJA-1-2-3 are decrease from 2/2/2 to 1/1/1 because of limit of transmission,

and blocked some timeslot PTCSCR-1-2-3 are congestion

Resolve ways: Replace cell from 900 cell to 1800 cell in PTCSCU-2 to avoid interfering, and absorb some traffic. Add more transmission timeslot and recovery to 2/2/2 in PTCIJA-1-2-3 Make traffic balanced between PTCSCR-1/PTCIJA-3/PTCSCU-2 Adjust azimuth from 240 to 270 in PTCIJA-3

Adjust E-tilt from 2 to 7 in PTCSCR-1 Adjust azimuth from 120 to 150 in PTCSCU-2 Add a TRX in PTCSCR-1/2/3

Hardware problemcrossed feeder cables


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p

Problems: There are more drop calls and handover failures times in each cell A little interfering in each cells in uplink(interfering band) and downlink(bad quality) MR are more in band 0~2 in path balance statistics result It showed crossed cables in this site: plan azimuth: 160/240/330, DT test 240/330/160.

Resolve ways: Have wrong frequency plan Get some frequency interfering Have wrong neighbor relationship Get some drop calls in each cells

All statistics and DT test result are normal after adjust crossed cables

Hardware problem-TRX problem


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Problems: TRX configuration:2/2/2 in URJDG-1-2-3 TRX8(2nd in URJDG-3, 1 cabinet) can not seizure any TCH in several days Have radio link alarm in this TRX Cant resolve the problems after swapping configuration data/slot in cabinet Result: TRX hardware problem Statistics results in cell and TRX level are normal after replaced TRX

Hardware problem-connecting cable wrong-3012


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p g g

Problems: In TRX 5, TRX configuration is 3/3/2 the path balance is main in RANK11, it

means that uplink is bad. Check on site, the RDX cables are

connecting wrong, it means there is noRDX receiver in TRX5

After adjust the connecting cable, thepath balance in TRX5 is normal.

Configuration wrong-HO between systems-2


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The external handover between QRBSCH(T4503XA,XB,T4504XA,XB) and KRBSCN3 (T3013XB),from external BSC handover performance, handover normal from T3013XB toT4503XA,XB,T4504XA,XB), but all handovers failures from 4503XA,XB,T4504XA,XB(Huawei) toT3013XB(Nokia) with the reason of invalid cell.

We checked the Configure external LAC data in MSC,BSC and The external information fromIrancell. the external cell information is the same.

Make a trace in A interface.In the interBSS incoming handover requirement message, it is showingthat the external cell LAC=37F9(14329), but the LAC data which Irancell offered is 14327. this isthe problem why all outgoing interBSS handovers are failure from T4503XAXB,T4504XA,T4504XB(Huawei) to T3103XB(Nokia).

The results after modify the external LAC number in MSC and BSC

Configuration problem-frequency and hopping


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No hopping zone

hopping zone

hopping zone

Handover success rate is low in T4524XA,The target cell is T4106XA.

Check the frequency between T4524XAand T4106XA, and found TCH channel are

the same in TCH=23 (not active hopping) Check the data near these two site, only

the sites in this zone are not active hoppingfunction.

Active Hopping function in this zone, thehandover success rate is normal inT4524XA.

Configuration wrong-TRX receiver mode in 3012


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Problems: TRX configuration is 2/2/2, in TRX 10,11, handover

success times is low after expansion.

Check the data, the received mode is wrong. After adjust, the KPI is normal

Configuration wrong- MSC information wrong


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Problems: T4055,T4106 TCH seizure success times is 0. TCH traffic is low from incoming handover. Modified LAC number on 29th-Mar

Wrong plan data (TABSCH6) and wrong BSC data in MSC(TABSCH2). TCH seizure normal after adjust the BSC information in MSC.

Configuration wrong-BA table losed


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Problems: Drop call rate increased from 0.29% to 0.41% after some sites was cut over. RF drop call times are more than cut over. There almost no neighbor cells information in dedicate mode. But there are neighbor cells information in idle mode. BA1(BCCH) are not blank BA2(SACCH) are blank. Switch of user input are activate in these cells.

Result: Somebody activate the switch of user input wrongly when he made the autoconfig file.

System only updated BA1 table, and BA2 need to added manually when user input areactivation.

Transmission-problem in connector


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Problems: Immediate assignment fail times in BSC fail is 34672, this site is 17912(51.66%), immediate

assignment success rate is about 20%, it lead to immediate assignment success rate in BSC level is97.4%. it has affected the network for more than 2 months.

The problem is the transmission connector in DDF, the core (for signaling) and shielding (for groundprotect) cable are connected together, The signaling is connecting to the ground.. It will lead to thetransmission cant bear any traffic and business, and TMU with alarms in all time. it is the reason of

why there are so many immediate assignment fail times. The KPI recovery to normal after re-do the connector

Interfering-channel interfering


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In T4313XB have interference on TRX5, and HOSR is low, The most idle channels are in band4. Modify TCH frequency channel from 27 to 28.

After modified frequency T4313B HOSR recover normal.

Course contents


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Chapter 2 GPRS/EDGE system

1. Review of the GPRS/EDGE system2. Based technology

3. Data rate and coding algorithm


5. Statistics task and formula in common use

6. Call flowing in GPRS/EDGE

Review of GPRS/EDGE system


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PSTN Network

Billing Center

GBTS

TE

MT

MS

GBSC

Internet

A

Pb

Um

Gi

HLR/Auc/EIR

SMS-GMSC/IWMSC

MSC/VLR

SS7 Network

GSM Core Network

GGSN

CG

SGSN

DNS

GPRS Backbone

GbGb

Gs

Abis

Um

GPRS Core Network

EDGE PCU

OMC

Review of GPRS/EDGE system


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POMU: packet operation maintenance unit HSC: hot swap controller RPPU: radio packet process unit

13-15 for Gb interface Others for Pb interface 2 boards of L2PU in each RPPU Each RPPU support 100 EDGE channels/max

or 120 GPRS channels/max Suggest 50%fixed/50%dynamic PDCH channels

Course contents


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Chapter 2 GPRS/EDGE system

1. Review of the GPRS/EDGE system

2. Based technology

3. Data rate and coding algorithm


5. Statistics task and formula in common use6. Call flowing in GPRS/EDGE

Based technology


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Total 52 frame =12blocks*4+4idle

TBF: Temporary Block Flow: physical connection in packet n

Documents

Statistics Data Analysis and Optimization_new