statistics data analysis and optimization v 4.0
TRANSCRIPT
Statistics Data Analysis
and Optimization V4.0
for HUAWEI GSM/GPRS/EDGE System
Compiled by Jin/JiangxinE-mail: [email protected]
2008/5/8
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
course contents
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
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 results are throughout the optimization process.
Emphasis of the optimization
System performanceAccess
Channel success
Congestion
Drop
Handover
Traffic
Quality
Coverage
Frequency
1. Immediate assignment rate
2. CSSR
3. 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 traffic
14. TCHF and TCHH traffic balance
15. Overlay and underlay traffic balance
16. Coverage rate (DT)
17. BER/MOS
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, check cell health, consistency, frequency, LAC data, neighbor
Start optimization
Hardware solved and system test
Hardware solved and system test
Start optimization meeting
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
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
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
FAN BOX
SWITCH BOX
FAN BOX
AIR BOX
AIR BOX
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Common equipment
TRXCDU
air/fan
Review of BTS312
CDU: Combiner & Divider Unit
TRX: Transceiver Module
PMU: Power Monitoring Unit
TMU: Timing/Transmission & Management
PSU: Power Supply Unit
TES: Transmission Extension power Supply
TEU: Transmission Extension Unit
TDU: Time Distribution Unit
Function: Core of siteTimingTransmissionManagement
BSC
External synchronous clock
MMI man-machine interface
ExternalAlarmingcontrol
BIU
OMU
EAC MCK
Standby MCK
Extended BIU
DBUS Internal data bus
CBUS Internal control bus
TDU Internal clock bus
TMU
Combiner
Distributor
Distributor
CouplerTX1TX2
TX-COMBTX-DUP
RX1RX2RX3RX4
HL-out
RX2RX3RX4
RX1
HL-inRXD
TX/RX-ANT
RXD-out
CDU
In common use way: 2TRX+1CDU: TX-COMB and TX-DUP ,HL_in and RXD-out connected2TRX+2CDU: TX-COMB and TX-DUP connected or not connected( less loss)4TRX+2CDU: TX-COMB and TX-DUP connected6TRX+1SCU+1/2CDU: TX-COMB and TX-DUP ,HL_in and HL_out connected8TRX+2SCU+1/2CDU: TX-COMB and TX-DUP ,HL_in and HL_out connected
Especially the TX_out can be connected with TX_DUP and it can decrease 3db of
combination loss.
Distributor
CouplerTX1
RX1RX2
TX/RX-ANT1
Distributor
CouplerTX1
RX3RX4
TX/RX-ANT2
EDU and SCU
Tx_Comb
TX4
TX3
TX2
TX1
3dBBridge
3dBBridge
3dBBridge
SCU: no coupler Four carriers are combined output through 2steps of 3dB bridges plug loss is 6.8dB.
EDU: No combined loss
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 actuallyReceive: dividing receiver when TRU combined indepandent receiver when TRU no combined
Access link check Dual polarizationantenna
TTAoption
Lightning arrester
BTS rack
Jumper connector(DIN)
DIN connector Lightning arrester/feederconnector(DIN)
Jumper/TTA Connector (DIN)jumper
Jumper/TTA connector(DIN)
Antenna Connector(DIN)
FAN BOX
SWITCH BOX
FAN BOX
AIR BOX
AIR BOX
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Inside jumper
TRX jumperTX and RDX cables
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
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)
CM
MM
RR
LAPDm
SigL1
L3
L2
L1
MS
RR BTSM
LAPDm
SigL1
LAPD
SigL1
LAPD
SigL1
BTSM
RR
SCCP
MTP
BSSMAP
CM
MM
BSSMAP
SCCP
MTP
MSCBSCBTS
Um½Ó¿Ú A½Ó¿ÚAbis½Ó¿Ú
GSM protocol stake
Speech/channel coding
Speech A/D 8KHz, 260bit Speech codeSection
20ms13kbit/s Channel code
Interleaving Burst pulseCipher
22.8kbit/s,456 bits,20ms
Modulate 33.8kbit/s
transmission
Speech coding : Coding type: RPE-LTP sampling 8Khz,and 20ms/frame, in each frame there are 4 sub-frame then get a rate of 13kbit/s. 260bits/20ms=13kbit/sChannel coding: 456bit/20ms=22.8kbit/s
From 260 bits to 456 bits in a speech frame
Parity check 3bitsConvolution
Coder
50bit *2
132bit
78bit
456bitTail 4bits
Interleave
1 2 3 4 5 6 7 8 ... ...452 453 454 455 456
Block
8
16
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B0 B1 B2 B3 B4 B5 B6 B7
{A4,B0} {A5,B1} {A6,B2} {A7,B3} {B4,C0} {B5,C1} {B6,C2} {B7,C3}
Rectangular interleave
Diagonal interleave
456bit/8=57bit/frame
Two type of interleave: rectangular type and diagonal type
Frame structure and burst frame
0 1 2 3 2044 2045 2046 2047
0 1 2 3 48 49 5047
0 1 24 25
0 1 24 25 1 49 500
0 1 4 5 762 3
TB3
TB3
GP8.25 TB: Tail bit
TB3
TB3
GP8.25
GP: Guard period
TB3
TB3
GP8.25
TB3
TB3 GP 68.25
58 information bits 26 TSC 58 info bits
Constant bit 142
Info bit 39 Extended TS 64 Info. bit 39
sequence 41 Info bit 36
Normal burst (NB for traffic)
Freq correct burst(FB for for freq synchronization)
Sync burst (SB for time sync)
Access burst (AB for access)
1 hyper frame(for hopping FN)=2048 super-frames=2715648TDMA frames (3 hours, 28 minutes, 53 seconds and 760 milliseconds)
1 super-frame=1326TDMA frames (6.12 seconds)
1SACCH multiframe=26TDMA frames (120ms) 1 multiframe=51TDMA frames (235.4ms)
1TDMA frame=8 timeslots (120/26=4.615ms)
1 timeslot=156.25 bit duration (4.615/8=0.577ms)(1 bit duration: 0.577/156.25=3.69us)
BCCHCCCHSDCCH
TCHSACCH/TFACCH
1SACCH super-frame=104TDMA frames (480ms)
TS: training sequence
26-frame multi-frame24TCH/F+FACCH/F+1SACCH/TF+1idle (full-rate TCH)
1SACCH super-frame=4SACCH multi-frame=4*26=104frames(480ms) Full (Rxlevel/Rxqual)=(26-1idle) *4=100frame measure average Sub (Rxlevel/Rxqual)= 12 frame measure average( under DTX allowed) (52-59 frame and 4 SACCH frame)
TCH/H+FACCH/H+SACCH/TH (half-rate TCH)51-frames multi-frameMain BCCH: 5FCCH+5SCH+20BCCH+20CCCH+1idle=51frame Combined BCCH: (5FCCH+5SCH+4BCCH+12CCCH+16SDCCH/4+8SACCH/C4 )*2=102frameMain SDCCH : (32SDCCH/8+16SACCH/C8 +3idle)*2=102 frame
Combinations of frame and TA
TB
3
Information
571
Training sequence
261
TB
3
Information
57
147+8.25=156.25bit(0.577ms)
GB
3
1Bit period=0.577ms/156.25=3.68usTA=63bit/max*3.69us/bit=233us for normal cellRadius/max twice(ms to BTS to ms): 233us*300000km/s=70kmMax cell radius is 70km/2 35km1TA=1bit=554mTA=219bit/max in 2 timeslot extended cell,radius/max=120km
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
FCCHSCHBCCHPCHAGCH
BCCH
CCCH
Common Channel
SDCCHSACCHFACCHTCH/FTCH/H
DCCH
TCH
Dedicated Channel
PCH AGCH
Downlink CCCH
RACH CCCHCommon Channel
SDCCHSACCHFACCHTCH/FTCH/H
DCCH
TCH
Dedicated ChannelRACH
Uplink CCCH
Downlink and uplink channels
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 : 2Paging 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 36Pch 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 type 4 times in each Pch blocks for TMSI paging typeSo total paging times/max=Pch blocks/sec*(times in each Pch blocks)
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
Conversation
Call release
FCCH
SCH
BCCH
PCH
RACH
AGCH
SDCCH
SDCCH
TCH
FACCH
idle mode
“off” state
dedicated mode
idle mode
Functions of Channels
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
Path Loss(dB)=k1+k2log(d)+k3Hms+k4log(Hms)+k5log(Heff)+k6log(Heff)log(d) +k7(Diffraction Loss)+Clutter Loss
Note: the values are only reference to, and need to corrected in planning project.K1: loss constant for freq.
Density urban: K1=69.55+26.16lg(F)Urban : K1=69.55+26.16lg(F)-2[lg(F/28)]2-5.4)Country : K1=69.55+26.16lg(F)-4.78[lg(F)]2+18.33lg(F)-40.94)
K2: loss constant for distance: K3,K4: corrected coefficient for mobile antenna height K5,K6: corrected coefficient for BTS antenna heightK7: corrected constant for diffractionKclutter: corrected coefficient for clutter.
D: distance between mobile and (km)Hms: height of mobile antenna (m)Heff: efficient height of BTS antenna (m)
The case parameters in urban and country cities.
Planning software transmission model
Down-tilt, height and coverage
tg(B-A/2)=H/RB: down-tiltA: vertical beam widthH: antenna heightR1,2,3: coverage range
Frequency band and channels
890 915 935 960
Dulplex distance band : 45 MHz
GSM 900:
GSM 1800:
uplink downlink
1710 1785 1805 1880
Dulplex distance band : 95 MHz
uplink downlink
Uplink: F1=890.2+(n-1)*0.2 (MHz) ARFCN: 0-124Downlink: F2=uplink+45=f1+45 (MHz)
Uplink: F1=1710+(n-512)*0.2 (MHz) ARFCN: 512-884Downlink: F2=uplink+95=f1+95 (MHz)
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 1800
band
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
RLT (DL) and SACCH multi-frame (UL)
Radio_link_timeout (DL,S(T100) )S+2 when MS decode a SACCH multi-frame correctly, S<= RLT/max. S -1 when MS can’t decode a SACCH multi-frame correctly.S=0,MS gives up the radio resource connection, a drop call occurs.
SACCH-multi-frames(UL)Value +2 when BTS decode a SACCH multi-frame,<= SACCH-multi-frames/max.Value –1 When BTS can’t decode a SACCH multi-frame,Value=0.BTS stop transmitting downlink SACCH. and start T3109.When T100 timeout in handset ,a drop call occurs.When T3109 timeout in BTS,BTS release channel, BSC sends “Clear request” to MSC.
Reasons of RF lossInterfering Bad rx_lev Incorrect PWR control parameter.Hardware problem.TRX Pwr class difference in the same cell.HO drops.Neighbor cell relations problem.Incorrect HO algorithm and parameters RLT,SACCH-multi-frame not correct.
Measure reports (MR) and SACCH frameMS 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 cells’s 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 indicator DTX used indicatorThe rx_lev and rx_qual in uplink and downlinkThe rxlev,freq, BSIC of the 6 best neighbors
Frequency reuse and hopping
Common Reuse 4*3 pattern : 4 sites and 3 sector in one frequency groupLack of channel mode: BCCH 4*3, TCH 1*3 or 1*1 hoppingMRP:(multi-reuse pattern) freq. number of Bcch1≥ Tch2≥Tch3 ≥Tch4 ≥...... ≥ TchnIUO: intelligence underlay and overlayHopping: 4*3, 1*3, 1*1(1*3: MA >=2*TRX, ,1*1: MA >=2*TRX(total))
C/I=(useful signal)/(useless signal) =carrier/interference
Standard: C/I=9db project: C/I=12dbStandard: C/A=-9db, project: C/A=-6db
C/I must be comply for the formula as below: D=Distance of frequency re-useR=Radius of cellN=No. of frequency re-use (E.g. 4*3=12,1*3=3)
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 algorithmN: 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
Frequency hopping (4*3, 1*3, 1*1)
4*3 hoppingSame frequency as 4*3(MA)
1*3 hoppingEach 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 the azimuth 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
No co-channel frequency carriers in one BTS. The frequency separation between BCCH and TCH in the same cell should be not less
than 400K. When frequency hopping is not used, the separation of TCH in the same cell should be
not less than 400K. In non-1*3 reuse mode, co-channel should be avoided between the immediately neighbor
BTS. Neighbor BTS should not have co-channels facing each other directly. Normally, with 1*3 reuse, the number of the hopping frequencies should be not less than
twice of the number of frequency hopping TRX in the same cell. Pay more attention to co-channel reuse, avoiding the situation that the same BCCH and
BSIC in adjacent area.
Frequency planning principles
Principle of AMR AMR (Adaptive Multi Rate) is the set of different speech code rate. BTS and MS select and adjust
the 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 is
better than EFR/HR when system use AMR-FR and AMR-HR whether the interfering is high or low.
Improvement the re-use rate of frequency: the performance is better when system use the No. of frequency re-use=9(3*3) and 12(4*3) than N=12(4*3) and 18(6*3), It means that the system can offer higher No. of frequency re-use mode in the condition of the same speech quality.
Improvement the edge coverage. For C/I, AMR-FR 4.75k need 3dB while EFR 8dB to keep the FER<1%. It means that the performance is improved from 3dB to 8 dB in the coder-encoder between AMR-FR and EFR. So the MOS is improved at the edge of coverage.
Channel assignment of AMR
Channel assignment principle of AMR adjust AMR supports according to the busyness type, speech version, circuit pool when BSC receive
the 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, 2 ;0 < th[i] + hyst[i] < th[i+1] + hyst[i+1] < 63; i = 1, 2 ;
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
DT analysis and bad coverage/qualityDT analysis items
Coverage analysis (over CV, less CV, CV confusion, reflection, antenna connection wrong)BER analysis and suggestionFreq.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 KPI’sRxlev(Full&Sub)Coverage rateRxqual(Full&Sub)Call setup success rateDrop call rate Handover 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 surroundingHardware 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 processMiddle frequency interfering
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)
Wrong azimuth or Confused coverage
Wrong azimuthPlanning azimuth 85/170/240DT azimuth 330/220/60Neighbor relationship and frequency
Confused coverageNeed to check azimuth in cell 3201/3203Need to confirm in every cablesPending? Reflection?Neighbor relationship?
Wrong location and interfering
Wrong Long/LatiPlanning coverageNeighbor relationshipsFrequency interfering
Channel interferingPlanning coverage and azimuthBad Frequency planWrong coverage against planning
Overshooting and low coverage
Overshooting and interfering12km overshootingAdjacent frequency interferingNeighbor relationshipsDrop call
Low coverageDown-tilt, antenna heightPWR, VSWR, OOS,Surrounding
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
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
OOS and no main service cell
Out of service (OOS)VSWR-2 alarm?LapD or transmission broken?No power supply?Locked?
No main service cellSimulate rxlevelNo cell can offer main serviceoffer a main service cellInstall a new main service cell or site
Wrong CGI in MSC
Wrong CGI in MSCMS can’t make any callsAll calls are blockedTCH seizure times for call are 0 timesSupport incoming and outgoing handover
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 can’t 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 callsinterfering Bad rx_lev hardware 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 parameters Handover drop callIncorrect PWR control parameter.
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
BSC level taskBSC measurement performance
Cell level taskImmediate assignment SDCCHTCHCongestionDropHandoverConcentricChannel capacity and availability
TRX level taskPath 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
Channels CA300J:Channel Requests (Circuit Service)CA303J:Call Setup Indications (Circuit Service)CA304:Call Setup Indications Timed OutRA303G: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 (Traffic Channel)
Cell level statistics items introduction(1)HandoversCH310:Outgoing Internal Inter-Cell Handover RequestsCH311:Outgoing Internal Inter-Cell Handover CommandsCH313:Successful Outgoing Internal Inter-Cell HandoverH312A: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 Rejected) (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) (TCH)H322D:Failed Incoming Internal Inter-Cell Handovers (Reconnection to Old Channels)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) (TCH)H3429Ca:Failed Incoming External Inter-Cell Handovers (Timer Expired) (TCH) (Traffic Channel)
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)
Statistics in Trx levelIn common useMean Number of SDCCHs in Interference Band 1-5Mean Number of TCHFs in Interference Band 1-5Mean 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 level Rank 0-7 receive quality rank 0-7
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 SDCCHK3000:SDCCH Seizure Requests
SDCCH drop rate (%)= CM30:Call Drops on SDCCHK3003:Successful SDCCH Seizures
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 HandoversCH310: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
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Top 20 worst cells from statistics dataCompositor according to the cell level KPI’sSelect the top bad 20(or 10)cells in the main items according to times or rateAnalysis the relative bad KPI itemsSolved the bad cells that affect the BSS level performance result Worst cells
TOP 20 worst cells and DT method
●BSC level●Cell level●TRX level
We can resolve the problems from easy 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
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 value Get the best parameter results
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Boundary model of cells and BA table
HO outgoing boundary,HO_out
Select boundary,Reselect
HO Incoming boundary,HO_in
BCCH neighbor listTransmit in”system information message type 2” in BCCH In use of select and reselect cells64 cells max
SACCH neighbor listTransmit in”system 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.
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 ARFCNMS tune to the max rx-lev , and judge if it is the BCCHIf 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 flowing
The cell is not bared ;C1>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.
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 hasn’t reselect the cells in the past 15s:
To the same LAC, C1 of nei’s >present cell’s 5sTo the different LAC,C1 of nei’s >present cell’s value (C1+cell_reselect_hysteresis)Ms not reselection if has reselected in 15s
PT-T<0, H(pt-t)=0PT-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
Other parameters about reselect(1)CBA: No: normal, Yes: barredPI: No: C2 not used Yes: C2 used ,
PHASE2 MS reselection according to C2PHASE1 MS reselection according to C1
CBQ: No: normal ; Yes: 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: C1, thus MS prefer to reselect B
PI=1,C2 have some affect (suppose to the same layer) micro CRO=20 , macro CRO=0 so micro A: C2=55,> macro B: C2=45, thus MS prefer to reselect A
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
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,CRHSDCCH 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 updateSMSATTCDB (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 TCHIf idle SD<N1+8,then count+12<=restimeIf idle SD=N1+8,the not adjust.
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Reasons of congestion
Reasons of TCH congestionTraffic not balanced between service and neighborsTraffic not balanced between underlay and overlay in concentricHardware 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 functionLower “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
Normal Cell boundary model
HOoutgoing boundary,HO_out
Select boundary,Reselect
HOIncoming boundary,HO_in
Control traffic by cell boundaryrxlev_access_min↘C1/C2↗cell radius↗SD/TCH traffic↗rxlev_access_min ↗SD/TCH traffic↘congestion↘Min_DL_level_on candidate cell↗difficult to incoming HOtraffic↘congestion↘Adjust HO_hysteresisadjust handover boundaryadjust traffic between service cells and neighborsAdjust PGBT HO thrsh. as –HO parameter relief congestionAdjust PI, CRO ,PT, TO, CRH,TX_powerAdjust TRXs/channels/cells/sitesActive Half-rate functionOtoU(UtoO) HO Received Level Threshold↘MS stay more time in overlay traffic in underlay ↘congestion in underlay↘
Abnormal boundary (-PBGT and pingpong HO)
2-HO to nei cells1-setup
Rselect
HO_out.
Reselect>RHO_out reselect
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)=ΔRXLEV_BCCH-ΔRXLEV_ACCESS_MIN>02, PBGT(N)=-ΔRXLEV_BCCH >HO_MARGIN , so C1(cell B)-C1(cell A) = HO_MARGIN+ΔRXLEV_ACCESS_MIN <0MS will setup calls in the cell A,and handover to cell B immediately.Note: Need to select “inter-cell ho thrsh.” =0 and “PBGT ho thrsh”<64. Inter-cell HO thrsh. In cell B to cell A Need more than the value from cell A to cell BOr this parameter will lead to pingpong HO when using –PBGP HO process.
HO to B
RHO_in>RHO_out lead to pingpong HO
RHO_OUT
HO to A RselectHO_out
HO_in
Eg.1: reselect>HO_outHO_MARGIN A→B= -5, RXLEV_ACCESS_MIN=5(-105dbm)HO_MARGIN B→A=8, RXLEV_ACCESS_MIN=5(-105dbm)To cell A: ΔRXLEV_ACCESS_MIN+HO_MARGIN = (5-5)-5 = -5<0The ms setup calls in cell A ,and immediately handover to cell B
Eg.2: reselect<HO_outHO_MARGIN A→B=-5, RXLEV_ACCESS_MIN=15(-95dbm)HO_MARGIN B→A=8, RXLEV_ACCESS_MIN=5(-105dbm)To cell A: ΔRXLEV_ACCESS_MIN+HO_MARGIN = (15-5)-5 = 5>0The ms setup calls in cell A ,but not HO to cell B immediately
Direct retry and load HO
Cell B
Cell ADR to the nei cells
RHO_out
Rselect
Sharing the traffic by DR(suggest not allowed)
MS2
MS1
RHO_out
MS1 ho to B
RHO_out
load ho thrsh
Load HO
MS1
MS1Load ho band
Load 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 BThere is free TCH channels in cell B
TCH dropsReasons of drop callsInterfering Bad 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 cabinetRLT, 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 problemRadio 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 Channel)] +[Failed Outgoing Internal Inter-Cell Handovers (Timer Expired) (TCHH) (Traffic Channel)] +[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 Channel)]
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Call process of MOCMSC BSC BTS MS
Channel Request(RACH)1Channel Required2
Channel Activation3
Channel Activation Ack4
Immediate Assigment Command5 Immediate Assigment (AGCH)6
CM Service Request(SDCCH)7CM Service Request8CM Service Request9
UA(SDCCH)10Authentication Request11 Authentication Request(SDCCH)12
Authentication Reponse(SDCCH)13Authentication Reponse14
Ciphering Mode Command15Ciphering Mode Command16 Ciphering Mode Command(SDCCH)17
Ciphering Mode Complete(SDCCH)18Ciphering Mode Complete19
TMSI Reallocation Command20 TMSI Reallocation Command(SDCCH)21
TMSI Reallocation Complete(SDCCH)22TMSI Reallocation Complete23
Setup(SDCCH)24Setup25
Call Proceeding26Call Proceeding(SDCCH)27
Assignment Request28Channel Activation29
Channel Activation Ack30
Assignment Command(SDCCH)31
SABM(FACCH)32Establish Indication33
UA(FACCH)34
Assignment Complete(FACCH)35Assignment Complete36
Channel Release37
RF Channel Release Ack41
Alerting42Alerting(FACCH)43
Connect(FACCH)45
Connect Ack(FACCH)46Connect Ack47
Measurement Report(SACCH)48Prep_Measurement Result49
Disconnect(FACCH)50Disconnect51
Connect44
Release52Release(FACCH)53
Release Complete(FACCH)54Release Complete55
Clear Command56Channel Release(FACCH)57
Deactivate SACCH58DISC(FACCH)59
UA(SACCH)60Release Indication61
RF Channel Release62
RF Channel Release Ack63Clear Complete64
SCCP Release65
SCCP Release Ack66
Estableish Indication
Deactive SACCH38
Release Indication39
RF Channel Release40
Call process of MTCMSC BSC BTS MS
Channel Request(RACH)4Channel Required5
Channel Activation6
Channel Activation Ack7
Immediate Assigment Command8 Immediate Assigment (AGCH)9
SABM Paging Response(SDCCH)10Paging Response(SDCCH)11Paging Response12
UA(SDCCH)13Authentication Request14 Authentication Request(SDCCH)15
Authentication Reponse(SDCCH)16Authentication Reponse17
Ciphering Mode Command18Ciphering Mode Command19 Ciphering Mode Command(SDCCH)20
Ciphering Mode Complete(SDCCH)21Ciphering Mode Complete22
TMSI Reallocation Command23 TMSI Reallocation Command(SDCCH)24
TMSI Reallocation Complete(SDCCH)25TMSI Reallocation Complete26
Setup(SDCCH)28Setup27
Call Comfirm30 Call Comfirm(SDCCH)29
Assignment Request31Channel Activation32
Channel Activation Ack33
Assignment Command(SDCCH)34
SABM(FACCH)35Establish Indication36
UA(FACCH)37
Assignment Complete(FACCH)38Assignment Complete39
Channel Release40
Alerting46 Alerting(FACCH)45
Connect(FACCH)47
Connect Ack(FACCH)50Connect Ack49
Measurement Report(SACCH)51Prep-Measurement Result52
Disconnect(FACCH)53Disconnect54
Connect48
Release55Release(FACCH)56
Release Complete(FACCH)57Release Complete58
Clear Command59Channel Release(FACCH)60
Deactivate SACCH61DISC(FACCH)62
UA(SACCH)63Release Indication64
RF Channel Release65
RF Channel Release Ack66Clear Complete67
SCCP Release68
SCCP Release Ack69
Paging1Paging Command2
Paging Request3
Establish Indication
Deactive SACCH41
Release Indication42
RF Channel Release43
44 RF Channel Release Ack
Circuit paging call flowingA1: received circuit paging messages from MSC A2: received circuit paging messages from MSC via G-s interface B1: circuit paging command to BTS
Circuit Paging (BSC level)
CCCH overload call flowingA1: circuit paging PCH overloads of Abis interface B1: circuit paging CCCH overloads of Abis interface
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 allocationF1-F3: unsuccessful assignments(radio interface fail,reversion to the previous channel)H2-H4: unsuccessful assignments(other causes)
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 handovers B1: attempt outgoing BSC handovers (from 900) C1: attempt outgoing BSC handovers (from 1800)D1: outgoing BSC handovers E1: outgoing BSC handovers (900->1800) F1: outgoing BSC handovers (1800->900)
Successful outgoing BSC handoversA1: successful outgoing BSC handovers B1: 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)
Unsuccessful outgoing BSC handoversA1: unsuccessful outgoing BSC handovers with successful reversion B1-B3: unsuccessful outgoing BSC handovers with unsuccessful reversion
Incoming BSC HO (BSC level)
Unsuccessful incoming BSC handoversA1-A5 : unsuccessful incoming BSC handovers B1-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 handovers B1: 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
Immediate 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)
MS BTS BSC
.ASSIGN CMMAND
MSC
ASSIGNMENT REQUEST
SABM
UAESTABLISH INDICATION
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 9TCH-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 call TCH -ATT-C8: attempted TCH seizures for MOC TCH -ATT-C9: attempted TCH seizures for MTC TCH -ATT-C10: attempted TCH seizures for call-reestablish TCH -ATT-C13: attempted TCH seizures for directed retry TCH -ATT-C14: TCH queue requests TCH -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 MTC TCH -SUCC-C101--103: successful TCH seizures for call-reestablishTCH -SUCC-C13: successful TCH for directed retryTCH -SUCC-C54: successful assignments of speech v1 TCH TCH -SUCC-C55: successful assignments of speech v2 TCH TCH -SUCC-C56: successful assignments of speech v3 TCH
Assignment (cell level)
TCH call drop (cell level)
Call drop processA1: TCH call drop (error indication)A2: TCH call drop (connection failure)
MS BTS' BSC Ori-Cell
HANDOVER ACCESS
UA
Intercell Handover Request
TCH-ATT-C11
BSC Des-Cell BTS''
MR Handover algorithm
HANDOVER COMMAND
Intercell Handover Response
HANDOVER DETECT
CH ACTCH 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
SABM TCH-SUCC-C11
Internal inter cell HO
Internal inter cell handoversSD-ATT-C2: attempted SDCCH seizures(all) TCH -ATT-C3: attempted TCH seizures(all) TCH -ATT-C11: attempted TCH seizures for intraBSC incoming cell handover TCH -ATT-C17: attempted TCH seizures for intracell handover TCH -SUCC-C17 : successful TCH seizures for intracell handover TCH -SUCC-C3: successful TCH seizures(all) TCH -SUCC-C11: successful TCH seizures for intraBSC incoming cell handover SD-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 handover)A1: successful intracell handoversB1: successful incoming internal intercell handovers C1: successful incoming internal intercell handovers (from900) D1: successful incoming internal intercell handovers (from1800)E1: successful dual-band intercell handovers F1: 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 handover B1: successful incoming internal intercell handovers (from900) C1: successful incoming internal intercell handovers (from1800) D1: successful dual-band intercell handovers E1: successful incoming internal intercell handovers
incoming internal inter cell HO failureA1-A7: unsuccessful incoming internal inter cell handoversB1-B6: unsuccessful incoming internal inter cell handovers(other causes)
Internal inter cell HO failure
Outgoing internal inter cell HO failureA1-A7: unsuccessful outgoing internal intercell handovers B1: 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 reversion H1-H2: unsuccessful internal intercell handovers with unsuccessful reversion I1: unsuccessful outging cell handovers with successful reversion J1-J2: unsuccessful outging cell handovers with unsuccessful reversion
Outgoing interBSC inter cell HO
outgoing Inter bss inter cell HO attemptedA1: attempt outgoing interBSC intercell handovers B1: inter BSC outgoing cell handovers C1: outgoing interBSC inter cell handovers(to900cell) D1: outgoing interBSC inter cell handovers(to900cell) E1: successful dual-band intercell handovers F1: attempted outgoing intercell handovers(12 causes)
outgoing Inter bss inter cell HO successfulA1: successful outgoing interBSC intercell handovers B1: successful outgoing interBSC inter cell handovers(to900cell) C1: successful outgoing interBSC inter cell handovers(to900cell) D1: successful dual-band intercell handovers E1: successful outgoing intercell handovers(12 causes)
BTS BSC1 MSC/VLR
HANDOVER REQUIRED
HANDOVER COMMAND
CLEAR COMMANDCLEAR 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 failureA1: unsuccessful outgoing BSC handovers with successful reversion B1-B3: unsuccessful outgoing BSC handovers with successful reversion C1: unsuccessful outgoing cell handovers with successful reversionD1-D3: unsuccessful outgoing cell handovers with unsuccessful reversion
MS Other BSC
HANDOVER ACCESS
UA
HANDOVER REQUIRED
TCH-ATT-C12
HUAWEI BSC HUAWEI BTS
HANDOVER COMMANDHANDOVER REQUEST ACK
HANDOVER DETECT
CH ACTCH ACT ACK
HANDOVER COMPLETE
TCH-ATT-BSC4SD-ATT-BSC3
MSC
TCH-ATT-C15 QUEUEING INDICATIONTCH-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 handovers TCH -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 HO
incoming inter bss HO Success A1: successful incoming inter bsc inter cell handover B1: successful dual-band intercell handovers C1: successful incoming intercell handovers
inter bss incoming handover failureA1-A5 : inter bsc incoming cell handovers
Intracell ho successA1: successful intracell handovers
Intracell ho failureA1-A7: unsuccessful intracell handovers
Intracell HO
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
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 MR MR MR MR
Consecutive MR flow
Filter length
MR MR MR MR
N
Consecutive MR flow
Interpolation m missing MRN+1 N+m+1 N+m+2
MR
MR voting (N/P) for GSM0508 protocolN(N1-N8): MR numbers used to voting process in PC and HO P(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/N1-4 Parameters relation to HO: P5-8/N5-8 P/N5-8 >P/N1-4 When the rxqual or rxlev is not good ,the system try to adjust PWC before HO
• Process of power control commands– It takes 3 measurement report periods(3*480ms) from command
sending to execution.
SA0 SA1SA0 SA0SA1SA1 SA2SA2SA2 SA3SA3SA3
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 and power control message.
Power Control Overview
• Huawei PC algorithm: HW I and HW II power control
Measurement report pre-processing
Power control algorithm
selection
Yes
HW I power control
algorithm
HW II power control
algorithm
GSM0508 power control
Algorithm (ordinary)
PWC algorithm overview
Parameters of ordinary PWR control windowMS: uplink
UL 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=5 N3/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 uplink interference, 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 downlink interference, reduce power of BTS
So it mainly means UL PWC in the Power Control process on this hand.
-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=1Rx_qual thrsh.for DL decrease=1
Rx_qual thrsh.for UL increase=5Rx_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
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 <MAX PWC step Stable level = current level + the adjustment value
Huawei I PWC algorithm (average PWC)
MS: uplinkInitial RX_LEV ExpectedStable RX_LEV Expected>UL edge hoUL RX_LEV CompensationUL Qual. ExpectedUL Qual. CompensationMAX PWC Step
PWC IntervalMS PWC PeriodFilter 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 CompensationDL 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)
Lack of huawei I PWC algorithm: Average PWC algorithm has a delay when system analysis the MRs ,so system can’t adjust rapidly.System only analysis the past MR results and can’t 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_Lev
↑AdjStep_Lev ↓ AdjStep_Qul ↑AdjStep_Lev
↑AdjStep_Lev ↑ AdjStep_Qul ↑ max(AdjStep_Lev,AdjStep_Qul)
↑AdjStep_Lev No action ↑AdjStep_Lev No action ↓ AdjStep_Qul ↓ AdjStep_Qul No action ↑ AdjStep_Qul ↑ AdjStep_Qul No action No action No action
Huawei II PWC algorithm (PWC direct and value)
Adj. step_lev in UL: UL rx_lev<UL rx_lev lower thrsh. ,MS increase pwr adj. step_lev=(UL rx_lev lower thrsh. +UL rx_lev upper thrsh.)/2-ul rx_lev UL rx_lev >UL 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 <UL rx_lev upper thrsh, no adjust pwr.
The adj. step_lev in DL ,adj.step_qual in UL/DL are the same as the adj. step_lev in UL.
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_Lev
↑ AdjStep_Lev ↓ AdjStep_Qul ↑ AdjStep_Lev
↑ AdjStep_Lev ↑ AdjStep_Qul ↑ max(AdjStep_Lev,AdjStep_Qul)
↑ AdjStep_Lev No action ↑ AdjStep_Lev No action ↓ AdjStep_Qul ↓ AdjStep_Qul No action ↑ AdjStep_Qul ↑ AdjStep_Qul No action No action No action
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Summary and classification of HOSummary 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 cellSystem 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 system else 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
M.R.preprocessing
Penalty processing
Basic ranking
Secondary ranking
HO voting
emergency HOTA
bad quality(BQ)rapid lev decrease
interfering
Load Sharing HO
normal HOEdgelayer
PBGT
Processing program
OMC forced HO
Directed retry
Overlaid/underlaid HO
Fast moving MS HO
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.
HO penalty and ranking rules
Ranking rulesM rule for ranking neighbor cells
it 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)
12345678910111213141516
The 6 strongest cell and service cell rx_lev bit000-110 and the strongest cell value is 000
The 6 strongest cell and service cell rx_lev bit000-110 and the strongest cell value is 000
Intercell ho hysteresis bitService cell=0Rx_lev(n)>rx_lev(s)+ho hys. Set 0else Set 1Compare intercell_ho_hysteresis and PBGT thrsh. The higher value is effective in the HO type
Intercell ho hysteresis bitService cell=0Rx_lev(n)>rx_lev(s)+ho hys. Set 0else Set 1Compare intercell_ho_hysteresis and PBGT thrsh. The higher value is effective in the HO type
Layer and cell priority bit4 layers and 16 cell priority/layer=64Pico 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
Layer and cell priority bit4 layers and 16 cell priority/layer=64Pico 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 bitLoad(s)>load ho thrsh. Is set 1 else 0Means if it is load busy ,it is put a low part in the nei list
Load sharing bitLoad(s)>load ho thrsh. Is set 1 else 0Means if it is load busy ,it is put a low part in the nei list
Co_BSC/MSC bitService cell =0If nei cells and S_cell are in co_BSC/MSC,value is set 0 else 1If rx_lev(s/n) is lower than inter_layer_ho_thrsh. and inter_layer_ho_hysteresis the bits are set 0If co_BSC/MSC is not allowed the value is set 0.
Co_BSC/MSC bitService cell =0If nei cells and S_cell are in co_BSC/MSC,value is set 0 else 1If rx_lev(s/n) is lower than inter_layer_ho_thrsh. and inter_layer_ho_hysteresis the bits are set 0If co_BSC/MSC is not allowed the value is set 0.
Cell type bitInternal =0external-=1
Cell type bitInternal =0external-=1
Inter layer ho thrsh. BitRx_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
Inter layer ho thrsh. BitRx_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 bitReserve bit
Emergency HO and load HO voting
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)=A1×C(nt) + A2×C(nt-t) +…+ A8×C(nt-7t)C (nt) is the uplink RX_Level of the serving cell in the MR received at the time of "nt".Filter A1 ~ A8=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_qual < rxqual thrsh for interf. HO.
Load HO votingCell Load HO Criterions :
System load of BSC < system flux thrsh. for load HO load > load HO thrsh. Load of target cell < load HO threshold
Normal HO, fast moving HO and concentric HO votingNormal HO voting
Edge HO Criterion: Rx_lev <edge HO rx_lev thrsh. In N/P
Inter layer HO criterions: Rx_lev(n) > inter layer ho thrsh. + inter layer ho hysteresis. And target cell priority should be higher than the serving cell’s. 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 <MS Fast_Moving Time Thrsh.
Concentric HO voting Criterion from overlaid(small) to underlaid(large):
TA value >=TA threshold + TA hysteresis Or Rx_lev <= Rx_lev threshold -Rx_lev hysteresis
Criterion from underlaid to overlaid: TA value <= TA threshold - TA hysteresis And Rx_lev <= Rx_lev threshold + Rx_lev hysteresis
Chapter 1 GSM system1. Work items in an optimization project
2. 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 use
7. 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 use
12. Power control algorithm
13. Handover algorithm
14. Cases according to statistics data
Congestion, interfering and TRXProblems: 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 problem- crossed feeder cablesProblems: 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 problemProblems: 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 Can’t 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-312Problems: TRX configuration:3/5/3 in NSRDG-1-2-3 TRX12(5th TRX in NSRDG-2, two cabinet) can not seizure any TCH in some days Have “radio link alarm” in this TRX SCU+2CDU mode in this cell, 4 TRX connect to TX-DUP port in one CDU via 1st CDU. So that can decrease 1 bridge of combiner( save 3 dB of combiner loss) The other TRX connect to TX port in 2nd CDU. Result:wrong jump cables connecting. There is no jump cables between TX-COM and TX-DUP in 2nd CDU. Statistics results are normal after a jumped cable between TX-COM and TX-DUP.
Hardware problem-connecting cable wrong-3012Problems: 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 no RDX receiver in TRX5
After adjust the connecting cable, the path balance in TRX5 is normal.
Configuration wrong-HO between systems-1Analysis-1 Low handover success rate(about 25%) and effect to the KPI of BSC level. Low handover performance of “outgong inter BSC intercell handover success The target cell of other BSC is belong to different system. Handover performance are normal from other BSC to present BSC in boundary. The loss times are local from “handover required” to “handover command” There is no “handover ACK” from MSC after “handover required” from BSC.
Analysis-2 BSC receive “handover reject” from A interface after “handover required” by Trace function. It show “ invalid information content” when decoded the “handover reject” information. There are 3 type of information are not defined by GSM0508 protocol, they only defined by different supplier.-- “Response Request , Current Channel , Speech Version” in BSSMAP. ECSC information between different band are be included in these 3 type information. One system defined 2 type of information but the other system defined 3 types. The result are normal after adjust the content of handover in MSC and activate ECSC in BSC.
The external handover between QRBSCH(T4503XA,XB,T4504XA,XB) and KRBSCN3 (T3013XB), from external BSC handover performance, handover normal from T3013XB to T4503XA,XB,T4504XA,XB), but all handovers failures from 4503XA,XB,T4504XA,XB(Huawei) to T3013XB(Nokia) with the reason of “invalid cell”.
We checked the Configure external LAC data in MSC,BSC and The external information from Irancell. the external cell information is the same.
Make a trace in A interface.In the interBSS incoming handover requirement message, it is showing that the external cell LAC=37F9(14329), but the LAC data which Irancell offered is 14327. this is the 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 wrong-HO between systems-2
Configuration problem-frequency and hopping
No hopping zone
hopping zone
hopping zone
Handover success rate is low in T4524XA, The target cell is T4106XA.
Check the frequency between T4524XA and 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 hopping function.
Active Hopping function in this zone, the handover success rate is normal in T4524XA.
Configuration wrong-TRX receiver mode in 3012Problems: 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 wrongProblems: 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-NCC permittedProblems: Difficult handover from T4110XA, XB to the other cells. Handover normal from TT4110XC to the other cells. Compare the parameters between T4110XA,XB,XC NCC permitted is only selected “0 allowed” The handover recovery to normal in T4110 after adjust NCC permitted.
Configuration wrong-BA table losedProblems: 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” are
activation.
Transmission-crossed connectingProblems: SRBSC has high congestion about 14%. Select the most congestion site T4781, arranged a DT team to test the site, found that there is only
T4795’ CGI and frequency near the T4781. But the two sites’ distance is 87KM, the only possible reason is that some wrong data has been configured or wrong connection between the two sites.
Checked the handover of T4795, found that the cell can only handover to the other two cells in same site. Added the T4795’s neighbor cell as the T4781 location. Later, the T4795’s handover and congestion performance is improved. But we do the same to the T4781. this site no any changed, the KPI of this site was also bad.
Checked other site with the same problem in T4784, high congestion and low HOSR. so it is possible that the three site has swap relation among T4781, T4795 and T4784. the KPI are rapidly enhanced in these three sites and SRBSC after we changed the neighborhood T4781 as T4784, T4795 as T4781, T4784 as T4795. It is proved situation what I suspected after we arranged a DT test.
BSS engineer feed back that they found the optic port of transmit had been swapped among these three site and recovery on 13th-Apr. And we change back to the neighborhood data in these cells. the below is the compare of the before and after adjust, total in T4781,T4784,T4795.
Transmission-problem in connectorProblems: 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 is 97.4%. 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 ground protect) cable are connected together, The signaling is connecting to the ground.. It will lead to the transmission can’t 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
Version abnormal-TMU-1 the TRX was out of service in turns in T4090. it means that sometime OOS in some TRX, and the other time, the other TRX will OOS in burst. The traffic in these TRX will all be drop calls. When we check the result, the problem occurs suddenly, and found that the TRX with phase-loop
alarm. The KPI is normal after we reset the site in level 4.
Version abnormal-TMU-2 CSSR is low after cutover 18 sites from TABSCH6 to TABSCH5. Found there are 4939 times for TCH seizure failure times in T4084XC. TCH availability is 40%, TCH congestion rate is 1.1% Some channels in available TRX is red (can’t seizure any users) The KPI is normal after reset the site in level 4 on 3th-May.
Interfering-channel interfering 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.
Chapter 2 GPRS/EDGE system
1. Review of the GPRS/EDGE system2. Based technology
3. Data rate and coding algorithm
4. Parameters in common use
5. Statistics task and formula in common use
6. Call flowing in GPRS/EDGE
Course contents
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
Review of GPRS/EDGE system
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
Chapter 2 GPRS/EDGE system
1. Review of the GPRS/EDGE system
2. Based technology
3. Data rate and coding algorithm
4. Parameters in common use
5. Statistics task and formula in common use
6. Call flowing in GPRS/EDGE
Total 52 frame =12blocks*4+4idle
Based technology
TBF: Temporary Block Flow: physical connection in packet network. simulated with RR connection in GSM.TFI: Temporary Flow Identity: flag of TBF. 5bit(value0-31) and the TFI belongs to especial TBF. it can use the same or different TFI in one TBF FBI: final block identity. 1 bit to indicator if it is the LAST RLC blockUSF: uplink state flag: 3bit(0-7): control MSs to using channels with UFI in “dynamic type” RRBP: Relative Reserved Block Period,3 bit(0-7) , defines the location when ms send to network with “packet control ACK”or packet DL ACK”MAC mode: Three type of MAC mode: fixed allocation, dynamic allocation, extend dynamic allocation
Fixed type: BSS allocation data block for MS with fixed type. BSS will re-allocation data block when the first data block finished transmission but still have data block. Dynamic type: BSS allocation data block for ms with temporary type. BSS assign the USF in different PDCH channels,the packet data will transmission if the USF are the same between MS decoded and BSS allocated.Extend dynamic type: simulate with “dynamic” but the timeslots can more than the timeslot capacity of MS. RLC mode: confirm mode: each packet block need to confirm in each TBF with MS and network during transmission. Or the packed block will resent until be confirmed by each other. And TBF will release after be confirmed “finish” with each other.Non-confirm mode: need not to confirm in each TBF. TBF will release after finish transmitting the packet blocks.
Classes of MSClass A: can use circuit and packet business in the same timeClass B: MS can attach on GSM and GPRS/EDGE network in the same time, but only can use one of circuit or packet business in the same time. MS select GSM or GPRS/EDGE network automatically.Class C: MS can not attach on GSM and GPRS/EDGE network in the same time. MS select GSM or GPRS/EDGE network manually.
.Network operate mode: NO1: the core network send paging message in Gs(SGSN to MSC) interface. MS only need to detect paging in one type of channel(PCH or PPCH).-with Gs interface NO2: paging message only be sent in PCH for CS and PS paging. Because the PPCH is not configuration –with neither Gs nor PPCH. NO3: paging message is sent in PCH (for CS) and PPCH (for PS), MS need to detect PCH and PPCH message in the same time. –with no Gs but PPCH
Multi-timeslots capacity(1-29)it shows the capacity of MS in uplink and downlink for packet service. 1+4 or 2+3 timeslots in common by now.
Multi-TBF in PDCH channel: it shows the capacity for TBF connection in each PDCH channel.default value: 4 uplink+4 downlink TBF in each PDCH channels in the same time.7 uplink TBF or 8 downlink TBF/max in each PDCH channels
Based technology
LQC(link quality control mode)LA: link adaptation: using different MCS scheme in same Family to retransmit and can re-divided 2 RLC blocks to re-transmit.(bad BEP in low MCS, good BEP in high MCS)IR: Incremental redundancy: different MCS scheme in same Family to retransmit
LLC PDU divide to RLC PDU
Data packetRLC/MAC header
LLCheader
SNDCPheader
LLC FCS Dummy bits
LLC PDU
RLC/MAC BLKS
SNDCP PDU
BSN=0 BSN=1 BSN=2 BSN=3 BSN=127 BSN=0 BSN=1
Data packetRLC/MACheader
LLCheader
SNDCPheader
LLC FCS Dummy bit
LLC PDU
RLC/MAC blks
BSN=0 BSN=1 BSN=2BSN=N
1560bit/max
LLC PDU delivery turns in confirm mode
LLC PDU delivery turns in non-confirm mode
RLC PDU recombine to LLC PDU
PDU transmission
PDP context
READY timer expiry or Force to TANDBY
PDP deactive
PDP context
PDU reception
PDP deactive or Cancel Location
MM State Model of MS MM State Model of SGSN
IDLE
READY
STANDBY
IDLE
READY
STANDBY
READY timer expiry or Force to STANDBY or Abnormal RLC condition
Implicit Detach or
t imer exprity
Implicit Detach or
Cancel Location
Three state of MM: Idle: without available RA informationStandby: can implement RA update, selection, reselection, paging function, finished attached to GPRS network Can active PDP context, but no TBF,no transmission with data blockReady: can send and receive UDP, selection, reselection, no paging, cell information sometime with data block transmission in uplink/downlink on TBF
Conversion among different states in MM
Course contents
Chapter 2 GPRS/EDGE system
1. Review of the GPRS/EDGE system
2. Based technology
3. Data rate and coding algorithm
4. Parameters in common use
5. Statistics task and formula in common use
6. Call flowing in GPRS/EDGE
Modulating bitsD3i, d3i+1, d3i+2
Symbol parameter l
(1,1,1) 0
(0,1,1) 1
(0,1,0) 2
(0,0,0) 3
(0,0,1) 4
(1,0,1) 5
(1,0,0) 6
(1,1,0) 7
Coding scheme and rate
Coding scheme and rate
MCS-3
Family A
Family B
Family C
Family A padding
37 octets 37 octets 37 octets37 octets
MCS-6 MCS-9
28 octets 28 octets 28 octets28 octets
MCS-2
MCS-5 MCS-7
22 octets22 octets
MCS-1
MCS-4
34 +3 octets34 +3 octets
MCS-3
MCS-6
MCS-8
34 octets 34 octets 34 octets34 octets
Modem type Coding scheme
Bytes in RLC/MAC
Rate (kbps
)
PDCH/
16kbps
Binding idle ts(16kbps)/
max
Family
CS-(1-4)/GMSK
CS-1 23 9.05 1 / /
CS-2 33 13.4 1 / /
CS-3 39 15.6 2 6 /
CS-4 53 21.4 2 6 /
MCS-(1-4)GMSK
MCS-1 22 8.8 1 3 C
MSC-2 28 11.2 1 3 B
MSC-3 37 14.8 2 6 A
MCS-4 44 17.6 2 6 C
MCS-(5-9)8PSK
MCS-5 56 22.4 2 6 B
MCS-6 74 29.6 2 6 A
MCS-7 2*56 44.8 3 9 B
MCS-8 2*68 54.4 4 12 A
MCS-9 2*74 59.2 4 12 A
Coding scheme and rate
8PSK modeGMSK mode
9.112.2
14.4
20.2
8.811.2
14.817.6
22.4
29.6
44.8
54.4
59.2
0.0
10.0
20.0
30.0
40.0
50.0
60.0
CS-1 CS-2 CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8 MCS-9
kbps
GPRSEGPRS
Coding scheme and rate
Course contents
Chapter 2 GPRS/EDGE system
1. Review of the GPRS/EDGE system
2. Based technology
3. Data rate and coding algorithm
4. Parameters in common use
5. Statistics task and formula in common use
6. Call flowing in GPRS/EDGE
Uplink Number of successful uplink TBF establishment Number of uplink TBF establishment attempts (UL) TBF successful assignment rate (user defined) Number of uplink TBF abnormal release due to no channel Number of uplink TBF establishment failures due to no channel (UL) TBF congestion rate (user defined) Number of uplink TBF abnormal release due to N3101 overflow (MS no response) Number of uplink TBF abnormal release due to N3103 overflow (MS no response) (UL) TBF drop rate (user defined) Number of successful uplink assignments Number of uplink assignments (UL) successful packet assignment rate (user defined)
TBF and packet performance
Downlink Number of successful downlink TBF establishment Number of downlink TBF establishment attempts (DL) TBF successful assignment rate (user defined) Number of downlink TBF abnormal release due to no channel Number of downlink TBF establishment failures due to no channel (DL) TBF congestion rate (user defined) Number of downlink TBF abnormal release due to N3105 overflow (DL) TBF Drop rate (user defined) Number of successful downlink assignments Number of downlink assignments (DL) successful packet assignment rate (user defined)
PDCH occupy Mean number of occupied PDCHs Mean number of available PDCHs Number of PDCHs occupied by downlink TBF Number of PDCHs occupied by uplink TBF Total number of PDCHs occupied by TBF PDCHs occupied rate Number of attempts at converting TCH to PDTCH Number of successful conversions from TCH to PDTCH Number of dynamic PDCHs reclaimed by BSC
PDCH resource, access and retain
Accessibility and retainability Packet Accessibility Packet Retainability
Formulas in common use
Packet Retainability(%)=100%--
Number of uplink TBF abnormal release due to N3101 overflow (MS no response) Number of uplink TBF abnormal release due to N3103 overflow (MS no response)Number of downlink TBF abnormal release due to N3105 overflow)Number of successful uplink TBF establishment Number of successful downlink TBF establishment
Number of Successful Uplink TBF Establishment
Number of Uplink TBF Establishment AttemptsPacket Accessibility(%)=
TBF uplink congestion rate(%)=
Number of uplink TBF establishment failures due to no channel Number of uplink TBF abnormal release due to no channelNumber of uplink TBF establishment attempts
TBF downlink congestion rate(%)=
Number of downlink TBF establishment failures due to no channel Number of downlink TBF abnormal release due to no channelNumber of downlink TBF establishment attempts
Number of Successful Uplink TBF Establishment
Number of Uplink TBF Establishment AttemptsTBF uplink assignment success rate(%)=
Number of Successful downlink TBF Establishment
Number of downlink TBF Establishment Attempts
TBF downlink assignment success rate(%)=
Uplink TBF call-drop rate(%)=
Number of uplink EGPRS TBF abnormal release due to N3101 overflowNumber of uplink EGPRS TBF abnormal release due to N3103 overflowNumber of successful uplink TBF establishment
Downlink TBF call-drop rate(%)=Number of downlink TBF abnormal release due to N3105 overflowNumber of successful downlink TBF establishment
packet uplink assignment success rate(%)=
Number of successful uplink assignmentsNumber of uplink assignments
packet downlink assignment success rate(%)=Number of successful downlinkNumber of downlink assignments
EDGE RLC/MAC DL performance Mean rate of downlink EGPRS RLC( kbits/s ) Mean throughput of downlink single EGPRS TBF( kbits ) Number of downlink EGPRS RLC control blocks(NUMBER) Number of downlink EGPRS RLC data blocks using MCS1~9 Number of downlink EGPRS RLC dummy blocks(NUMBER) Number of MCS demotions on downlink EGPRS TBF Number of MCS upgrades on downlink EGPRS TBF Retransmission rate of downlink EGPRS RLC data block using MCS1~9(%) Total number of downlink EGPRS RLC data blocks
EDGE RLC/MAC UL performance Mean rate of uplink EGPRS RLC( kbits/s ) Mean throughput of uplink single EGPRS TBF( kbits ) Number of uplink EGPRS RLC control blocks(NUMBER) Number of uplink EGPRS RLC data blocks using MCS1~9 Number of uplink EGPRS RLC dummy blocks(NUMBER) Number of MCS demotions on uplink EGPRS TBF Number of MCS upgrades on uplink EGPRS TBF Retransmission rate of uplink EGPRS RLC data block using MCS1~9(%) Total number of downlink EGPRS RLC data blocks
EDGE RLC/MAC performance
GPRS RLC/MAC DL performance Mean rate of downlink GPRS RLC( kbits/s ) Mean throughput of downlink single EGPRS TBF( kbits ) Number of downlink GPRS RLC control blocks(NUMBER) Number of downlink GPRS RLC data blocks using MCS1~4 Number of downlink GPRS RLC dummy blocks(NUMBER) Number of MCS demotions on downlink EGPRS TBF Number of MCS upgrades on downlink EGPRS TBF Retransmission rate of downlink EGPRS RLC data block using MCS1~4(%)
GPRS RLC/MAC UL performance Mean rate of uplink GPRS RLC( kbits/s ) Mean throughput of uplink single GPRS TBF( kbits ) Number of uplink GPRS RLC control blocks(NUMBER) Number of uplink GPRS RLC data blocks using MCS1~4 Number of uplink GPRS RLC dummy blocks(NUMBER) Number of MCS demotions on uplink GPRS TBF Number of MCS upgrades on uplink GPRS TBF Retransmission rate of uplink GPRS RLC data block using MCS1~4(%) Total number of downlink GPRS RLC data blocks
GPRS RLC/MAC performance
LLC DL performance Downlink throughput(kbits/s) mean length of downlink LLC_PDUs mean LLC_PDU bytes per downlink TBF number of downlink LLC_PDUs discarded due to FLUSH_LL received number of downlink LLC_PDUs discarded due to timeout total bytes of downlink LLC_PDUs received total bytes of downlink LLC_PDUs sent total number of downlink LLC_PDUs received total number of downlink TBFs total number of LLC_PDUs sent
LLC RLC/MAC UL performance mean length of uplink LLC_PDUs mean LLC_PDUs bytes per uplink TBF total bytes of uplink LLC_PDUs sent total numbers of uplink LLC_PDUs sent total number of uplink TBFs uplink throughput(kbits/s)
BEP performance Times of 8PSK_MEAN_BEP=1~32(times) Times of GMSK_MEAN_BEP=1~32(times)
LLC and BEP performance
Course contents
Chapter 2 GPRS/EDGE system
1. Review of the GPRS/EDGE system
2. Based technology
3. Data rate and coding algorithm
4. Parameters in common use
5. Statistics task and formula in common use
6. Call flowing in GPRS/EDGE
Attach call flowing
Note: step2: option, occurs when MS move to new SGSNStep3: option,occurs when step 2 fail.Step4: option,occurs if there is no PDP context activeStep5: optionStep6: option, occurs when MS move to new SGSN or attach to network for the first time.Step7: relation with step1. Occurs when IMSI attach and Gs interface is configured
Detach ,packet paging, RA update(internal SGSN)
Detach: MS request Detach in most time . Also can SGSN.Packet paging: shows in Network Operator II (PCH configured only)RA updating : shows in internal SGSN.
PDP context active and deactivate in request by MS and network
Conversion between PS and CS
Conversion between PS and CSReason: relation with Class B of MS.Initial state: PS mode (in attach or standby or ready mode).Convert state: CS active (location update, cell reselection, incoming calls….)Suspend: plug up from PS.When finished CS ,MS will resume to PS mode (back to attach mode)
+T3190
-T3190
+T3141+T3164
-T3164+T3168
-T3141Reset N3101-T3168
For EDGE: EDGE packet channel request (11bit or 8bit) and indicate phase 1,phase 2, short access inside.For PS block: require to phase 1 and try to phase 2 access in non-confirm mode require and try to phase 2 access in confirm mode.For PS signalling (MM): require to phase 1 access.There is TFI and defined TBF in “immediate assignment”
Broken lines shows the phase 2 access polling information (TLLI)
Establish TBF in PS idle modeEstablish UL TBF in CCCH
phase 1 accessphase 2 access
Establish DL TBF in CCCH
Establish TBF in PS transmission modeEstablish UL TBF in DL transmissionEstablish DL TBF in UL transmission
Establish TBF (1)
Establish TBF in PS idle modeEstablish UL TBF in CCCH
phase 1 access phase 2 access
Establish DL TBF in CCCH
Establish TBF in PS transmission modeEstablish UL TBF in DL transmissionEstablish DL TBF in UL transmission
Establish TBF (2)
S/P: supplyment /polling: to indicator if RRBP is efficiencyS/P=0: no efficiencyS/P=1: efficiency
UL transmission in confirm and NON-confirm mode
Ws: windows size64~1024, need (Vs-Va)mod(SNS) Ws relation with multi-timeslot capacity Vs: 0~SNS-1 variable for sending state, Vs’=Vs+1 when finish sending blocks of BSN=VsVa: 0-SNS-1 variable for ACK state,update from ACK/NACK message
If T3182 timeout ,then N3102-pan_dec, until n3102=0 TBF releaseIf ms receive packet uplink ACK for (vs<va+ws),then N3102+pan-inc,
Timeslots 1 2 3 4 5 6 7 8
Window size 64~192 64~256 64~384 64~512 64~640 64~768 64~896 64~1024
In ONE TBF, WS only increase in RLC layerWS : 64~1024 Relation with PDCH ts.
MS BSS
RLC data block(TFI)
RLC data block(TFI,S/P=1(ES/P=01/10/11))
RLC data block(TFI)
Packet Downlink Ack/Nack
RLC data block(TFI)
RCL data block(FBI=1, S/P=1(ES/P=01/10/11))
Packet Downlink Ack/Nack(ÇëÇóÖØ «)
.
.
..
.
..
.
..ÖØÆôT3190
Packet Downlink Ack/Nack(FAI=1)
Æô¶¯T3191
Í £Ö¹ T3191
.
..RLC data block(TFI£¬ÖØ «Ö ʾ)
RCL data block(FBI=1, S/P=1(ES/P=01/10/11))Æô¶¯T3191
Í £Ö¹ T3191 Æô¶¯T3193
PACKET DL ASSIGNMENT/PACKET TIMESLOT RECONFIGURE
(Control Ack=1)
ÖØÆôT3190
ÖØÆôT3190
ÖØÆôT3190
ÖØÆôT3190
ÖØÆôT3190
ÖØÆôT3190
Í £Ö¹ T3190 Æô¶¯T3192
Í £Ö¹ T3190
.
..RCL data block(FBI=1, S/P=1(ES/P=01/10/11))
Packet Downlink Ack/Nack(FAI=1)
Æô¶¯T3191
Í £Ö¹ T3191 Æô¶¯T3193Í £Ö¹ T3190 Æô¶¯T3192
ÖØÆôT3190
MS BSS
RLC data block(TFI)
RLC data block(TFI)
RCL data block(FBI=1, S/P=1(ES/P=01/10/11))
Packet Control Acknowledgement
.
.
..
.
..
.
..ÖØÆôT3190
Æô¶¯T3191
Í £Ö¹ T3191
.
..
PACKET DL ASSIGNMENT/PACKET TIMESLOT RECONFIGURE
(Control Ack=1)
ÖØÆôT3190
ÖØÆôT3190
ÖØÆôT3190
Í £Ö¹ T3190 Æô¶¯T3192
RCL data block(FBI=1, S/P=1(ES/P=01/10/11))Æô¶¯T3191
Í £Ö¹ T3191 Æô¶¯T3193Í £Ö¹ T3190 Æô¶¯T3192
Æô¶¯T3193
Í £Ö¹ T3192
Packet Control Acknowledgement
DL transmission in confirm and NON-confirm mode
network MS
PACKET TBF RELEASE(release UL TBF , RRBP)
PACKET CONTROL ACKNOWLEDGMENT
RLC DATA BLOCK
(CV)
RLC DATA BLOCK
(CV=0)Release UL TBF
network MS
PACKET TBF RELEASE
(release DL TBF , RRBP)
PACKET CONTROL ACKNOWLEDGMENT
To idle mode if there is no UL TBF
Stop detech DLPDCH
Release TBF in UL/DL