Call Setup Failure and KPI

8/13/2019 Call Setup Failure and KPI

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Section 5 - CS Signalling Flow Diagrams


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Start

Best serversRSCP > -102dBm

Best serversEc/No > -12dB

Coverage Optimisation

Dominance Optimisation

AICH(ACK) received?RACH failureMessage sent?

UL coverage & RACHparam. Opt

(changing serving cell)

Check system message

Report & Finish

(FACH) RRC ConnectionSetup received?

Report & Finish

(Check failure cause)

(DCH) RRC Connection setupCompleted sent from UE?

Report & Finish(Reason of problem:

L1 sync fail)

Radio Bearer setupfailureReceived?

Report & Finish(Check failure cause)

RRC setup rejectreceived?

AC optimisation(check Noise Rise

Iub ConjestionNBAP

ALCAP

Problem CoreCheck AC

Iub Conjestion

Yes

No

Yes

No

Yes

No

No

Yes

No

Yes

Yes

No

Yes

No

No

Report & Finish

Yes

A

NeighbourlistOptimisation

MissingNeighbour ?

Yes

No

Call Setup Failure Analysis Process


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Call Setup Failure Analysis- Block B -UE WBTS RNC

Preamble/RACH

Acquisition Indicator/AICH

RRC: RRC Connection Request/PRACH

NBAP: RADIO LINK SETUP REQUEST

RRC: RRC CONNECTION SETUP/FACH

L1 Synchronisation

NBAP: SYNCHRONISATION INDICATOR

RRC: RRC CONNECTION SETUP COMPLETE/DCH

UE in CELL_DCH state

NBAP: RADIO LINK SETUP RESPONSE

A


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RACH Process

DownlinkBS

L1 ACK / AICH

UplinkMS Preamble

1

Not detected

Message partPreamble2

PRACH_preamble_retrans# PRACH preambles transmitted during one PRACH cycle without receiving AICH response

UEtxPowerMaxPRACH

RACH_tx_Max# preamble power ramping cycles that can be done before RACH transmission failure is reported

PowerRampStepPRACHpreamble

PowerOffsetLastPreamblePRACHmessage

Initial preample power:Ptx = CPICHtransmissionPower-RSCP(CPICH) +RSSI(BS) + PRACHRequiredReceivedCI

A


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AICH power setting

AICH is carrying the Acquisition Indicators (AI) to reply to RACH pre-ambles. All together 16 AI can be multiplexed on one access slot in AICH.

The parameter to be optimized:

the transmission power of AICH is relative to CPICH.

Range: [-22 5] dB, step 1dB, default -8 dB

Related parameters: PRACH parameters includingRACH_preamble_retrans, if AI power is too low for UE to decode, it keepssending preambles until the RACH_preamble_retransis exceeded.


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Total DL Common Channel Power

ServiceType

DefaultPower

MinimumActivity

MinimumAverage

Power

MaximumActivity

MaximumAverage

Power

CPICH 33 dBm 100 % 33 dBm 100 % 33 dBm

P-SCH 30 dBm 10 % 20 dBm 10 % 20 dBm

S-SCH 30 dBm 10 % 20 dBm 10 % 20 dBm

P-CCPCH

28 dBm 90 % 27.5 dBm 90 % 27.5 dBm

S-

CCPCH

33 dBm 25 % 27 dBm 115 %* 33.6 dBm

PICH 25 dBm 96 % 24.8 dBm 96 % 24.8 dBm

AICH 25 dBm 0 % - 80 % 25 dBm

Total - - 35.5 dBm

3.5 W

- 37.5 dBm

5.6 W


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Start

Best serversRSCP > -102dBm

Best serversEc/No > -12dB

Coverage Optimisation

Dominance Optimisation

AICH(ACK) received?RACH failureMessage sent?

UL coverage & RACHparam. Opt

(changing serving cell)

Check system message

Report & Finish

(FACH) RRC ConnectionSetup received?



Report & Finish(Reason of problem:

L1 sync fail)

Radio Bearer setupfailureReceived?




Iub ConjestionNBAP

ALCAP

Problem CoreCheck AC

Iub Conjestion

Yes

No

Yes

No

Yes

No

No

Yes

No

Yes

Yes

No

Yes

No

No

Report & Finish

Yes

B

NeighbourlistOptimisation

MissingNeighbour ?

Yes

No

Call Setup Failure Analysis Process


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Call Setup Failure Analysis- Block C -UE Node B RNC MSC / VLR MGW

RRC1. RACH: CCCH: RRC CONNECTION REQUEST

2. RADIO LINK SETUP REQUEST

3. RADIO LINK SETUP RESPONSE

6. DOWNLINK SYNCHRONISATION

7. UPLINK SYNCHRONISATION

11. DCCH: RRC CONNECTION SETUP COMPLETE

8. FACH: CCCH: RRC CONNECTION SETUP

4. ESTABLISH REQUEST (AAL2)

5. ESTABLISH CONFIRM (AAL2)

Start RX

RRC

NBAPNBAP

NBAPNBAP

ALCAP

ALCAP

ALCAP

ALCAP

DCH-FPDCH-FP

DCH-FP DCH-FP

RRC

RRC

RRC

RRC

Start TX

10. RADIO LINK RESTORE INDICATIONNBAPNBAP

9. INSYNCH INDL1 L1




Iub ConjestionNBAP

ALCAP

No

No

Report & Finish

Yes

B


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Interference

load

max planned load

max planned Interference

?

power

load

max planned load

max planned power

?

Admission Control (AC)

Will only allow UE access if the planned Maximuminterference and Maximum planned power is NOTexisted

Power and Interference


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L1 Syn FailUE Node B RNC MSC / VLR MGW

RRC1. RACH: CCCH: RRC CONNECTION REQUEST

2. RADIO LINK SETUP REQUEST

3. RADIO LINK SETUP RESPONSE

6. DOWNLINK SYNCHRONISATION

7. UPLINK SYNCHRONISATION

11. DCCH: RRC CONNECTION SETUP COMPLETE

8. FACH: CCCH: RRC CONNECTION SETUP

4. ESTABLISH REQUEST (AAL2)

5. ESTABLISH CONFIRM (AAL2)

Start RX

RRC

NBAPNBAP

NBAPNBAP

ALCAP

ALCAP

ALCAP

ALCAP

DCH-FPDCH-FP

DCH-FP DCH-FP

RRC

RRC

RRC

RRC

Start TX

10. RADIO LINK RESTORE INDICATIONNBAPNBAP

9. INSYNCH INDL1 L1


Report & Finish

(Reason of problem:L1 sync fail)

Yes

Yes

No


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Once the Node B has relayed the RRC Connection Setupmessage it starts to transmit the downlink DPCCH on the radiolink which has been configured by the NBAP: Radio Link SetupRequestmessage

Transmit power has been computed by AC and sent in theNBAP: Radio Link Setup Requestmessage

The UE uses the information within the RRC Connection Setupmessage to determine which scrambling and channelisationcodesto search for. The RRC Connection Setupmessage alsoprovides timing informationso the UE has some knowledge ofwhen to expect the start of the downlink frame and slot structure

Layer 1 Synchronisation failure- Check power of DPCCH


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Once UE has identified the precise timing of the downlink DPCCH itevaluates the quality over the first 40 ms. If the UE judges the quality to begreater than Qin it sends an CPHY-Sync-IND primitive to higher layers

After the first 40 ms have been judged the UE evaluates the DPCCH qualityevery 10 msbut based upon the previous 40 ms of DPCCH frames (slidingwindow)

Layer 3 of the UE uses timer T312 (6s)and counter threshold N312 (1)todetermine whether or not the L1 synchronisation has succeeded. Both T312and N312 were broadcast to the UE in SIB 1

T312 was started when UE initiated the establishment of the DPCH i.e. whenthe RRC Connection Requestmessage was sent

Layer 3 of the UE must count N312 CPHY-Sync-IND primitives before T312expires to consider the DPCH as established. If T312 expires then the UEconsiders the DPCH establishment attempt as a failure

Layer 1 Synchronisation failure- Check power of DPCCH


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Admission Control (AC) Summary

Admission Control

RAB admission decisionLoad change estimationProducing L2 parameters

Producing TFS

DL power allocation

Resourceinformation

Resource Manager

Radio resource informationCode allocation

Transport resource allocation

Resourcerequest

RB information

Loadinformation

Packet Scheduler

Radio resourceschedulingActiveset

information

Handover Control

Active state mobilitycontrol

Target BLER,B ER and SIR

Power Control

UL Outer looppower control

Iu

RAB setup/modify/release request

Load changeinformation

Load Control

Producing of loadinformation

Loadinformation

Call Setup Failure and KPI

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