understanding wcdma kpi notes: by john r garvin

8/11/2019 Understanding WCDMA KPI Notes: By John R Garvin

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Section 6Trouble shooting using KPIs andCounters


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Drive Survey Analysis Process Diagram

Drive test Data

Scran Drive testdata

RNC Counters

RNCParameters

Data loaded intosoftware tool

KPI reports perroute

KPI reportfailure analysis

Weekly report


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DPDCHincluding CRC Channel

DecoderDataincluding CRC AdmissionControl

BLERTargets

Min

Max

DPCCH

Pilot Bits

Pilot

EvaluationSIR

Min/Max SIR

DPCCH

TPC

RABAssign

mentfrom

core

UE Node B


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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

Signaling Bearer Set up

RRC connection attempts

The analysis of this keyperformance indicator

Detect problems ininteraction between UEand the network. This must

be setup before NASsignaling can take placefor mobility management,call control and sessionmanagement

Detect cells with highinitial access


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UE Node B RNC MSC / VLR MGW


8. FACH: CCCH: RRC connection rejectRRC

RRC Congestion/Dropped Connections

RRC Congestion/Dropped Connections

Dropped RRC connections attempts can be identified on behalf of thefollowing messages:

RRC connection Reject

RRC Connection release following the cell update request

Admission

Control


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Interference

load

max planned load

max planned Noise Rise

?

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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Call setup failuresSystem issue NodeB

RRC Connection Reject after RRC Connection Request

Good RF conditions

Admission Control can reject too many (or admit too many) connection requests due to wrongPrxNoise Rise measurements.


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NUMBER OF SUCCESSFUL RRC CONNECTION

ESTABLISHMENTS

A. This measurement provides the number of successful RRC connection

establishments screened by establishment cause

C. Reception by the RNC of a RRC CONNECTION SETUP COMPLETEmessage following a RRC connection establishment attempt..

NUMBER OF RRC CONNECTION ESTABLISHMENT

FAILURES

A. This measurement provides the number of RRC connectionestablishment failures screened by establishment failure cause

C. The measurement counts the number of RRC connection establishmentattempts which have not evolved into an RRC connection establishment.

A RRC connection establishment attempt is considered on the reception bythe RNC of a RRC CONNECTION REQUEST message.


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UE Node B RNC


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

Signaling Bearer Set up

NUMBER OF SUCCESSFUL NBAPRADIO-LINK SETUPS

A. This measurement provides thenumber of radio-links successfullysetup on a NBAP point of view,screened by Downlink AccessStratum configuration.

C. Receipt of a "RADIO LINK SETUPRESPONSE" or "RADIO LINKSETUP FAILURE" NBAP messagesent by Node B to the ControllingRNC in response to a RADIO LINKSETUP REQUEST message.

The measurement considers eachRadio Link mentioned as set-up inthe "RADIO LINK SETUPRESPONSE" or "RADIO LINK

SETUP FAILURE" NBAP message.


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Questions

What QoS is NBAP placed?What QoS are users placed?

What QoS is ALCAP placed?

Give 2 items found in an NBAP RADIO LINKSETUP REQUEST

Give reasons for NBAP failure?


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ISHO Failures


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ISHO AMR CallUE CNRNCNODE

B

RCC: Measurement Report

NBAP: RL Reconfigure Prepare

NBAP: RL Reconfigure Ready

NBAP: RL Reconfigure Commit

RCC: Physical ChannelReconfiguration

NBAP: Compressed ModeCommand

RCC: Measurement Report (GSMRSSI)

RCC: Physical Channel ReconfigurationComplete

RCC: Measurement Control



RCC: Measurement Report (BSICverified) RANAP: Relocation Required

RANAP: Relocation CommandRCC: Handover From UTRAN

Command RANAP: Iu Release Command

RANAP: Iu Release CompleteNBAP: Radio Link Deletion

Request

NBAP: Radio Link DeletionResponse

ReportingEvent Triggered

Handover Decision :BSIC verification

required



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B
















Request



RCC: Measurement Control NUMBER OF FAILED NBAPRADIO-LINK

RECONFIGURATION

PREPARATIONSA. This measurement provides thenumber of radio links failed inreconfiguration preparation.

- Receipt of a NBAP RADIO LINKRECONFIGURATION FAILUREmessage sent by Node B to the

Controlling RNC in response to aRADIO LINK RECONFIGURATIONPREPARE message.

Problems could be:

- No reception of RADIO LINK RECONFIGURATION READYmessage before a time-out

- RRM refusal (e.g. no power allocation, no code allocation)

- RNC I-Node refusal (e.g. no CID allocation)


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B
















Request



RCC: Measurement Control COMPRESSED MODECONFIGURATION SUCCESS

A. This measurement provides the

number of successful CompressedMode configuration (CM isconfigured by NBAP RLSetup/Reconfiguration for the BTSand RRC RBSetup/Reconfigurationfor the UE. It may then be activatedlatter if the UE needs to perform

radio measurements on another

UMTS frequency or on GSM,according a radio alarm

criteria).

C. Successful Compressed Modeconfiguration (Success on bothNBAP RL Reconfiguration

Response and RRC RBSetup/Reconfiguration Response,containing CM configuration).

D. Screened per CompressedMode configuration.


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Level

Received Signal Level(dBm)

From: To:

RXLEV_0 - -110

RXLEV_1 -110 -109

RXLEV_2 -109 -108

RXLEV_62

-49

-48

RXLEV_63 -48 -

In compressed mode

RXLEV is measured and

recorded by the UE.

Measurement Report


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RxLev = -110 + 4 = -106 dBm

4

POOR GSM

COVERAGE

No sui table

cell

Measurement Report


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ISHO delay is affected by;

RNC databuild2G neighbour lists provided to UE must be optimum.The longer the list the longer it takes UE to complete RSSI

measurements

UE measures all GSM carriers indicated in the Measurement Controlmessage prior to sending Measurement Report to RNC

If UE is not able to measure all GSM carriers within the measurementperiod it sends an empty Measurement Report

Handover to 2G Network


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Handover to 2G Network Once the UE has verified the BSIC measurement using the RRC: Measurement Reportthe

RNC sends a RANAP: Relocation Requiredmessage to the CS-CN .. The CS-CNresponds with a RANAP: Relocation Commandmessage.

The RNC instructs the UE to move to the 2G cell using the RRC: Handover Command fromUTRANmessage.

Information on 2G target cell


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ISHO Analysis from Drive Test Data

Need to analyse each ISHO attemptto determine;

Whether it was a necessary ISHO What the trigger mechanism was

(helps determine whether triggerthresholds are set correctly)

Whether the ISHO was successfuland if not the failure cause (e.g. Nocell found, UE failed BSIC

verification, UE didnt receiveHandoverFromUTRANCommand)

ISHO Success Rates

Process needs to be automatedwithin the drive test post-processing tool(s)


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Failure Analysis - Example

33%

33%

7%

7%

7%

13%

Network does not isse 'Cell Change Order'

UE responds to 'Cell Change Order' with a 'Failure'

UE does not react to the 'Cell Change Order'

UE does not report any GSM RSSI measurements

UE does not receive the CM 'Measurement Control'

UE fails BSIC verification


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B
















Request



RCC: Measurement Control NUMBER OF INTER-RATHANDOVER FROM UTRAN

COMMANDS PER CELL

A. This measurement provides thenumber of RRC HANDOVERFROM UTRAN COMMAND

messages (3G to 2G handover forCS or CS+PS) emitted by an RNC,acting as serving RNC,

for each cell controlled by this RNC

The reference cell of the involvedUE has to be under thecontrol ofthis RNC.

S O C


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B
















Request



RCC: Measurement ControlNUMBER OF INTER-RATHANDOVER FROM UTRAN

FAILURES PER CELL

A. This measurement provides thenumber of RRC HANDOVERFROM UTRAN FAILURE

messages (3G to 2G handover forCS or CS+PS) received by anRNC, acting as serving

RNC, for each cell controlled by thisRNC. The reference cell of theinvolved UE has to be

under the control of this RNC.

C. Reception of a RRCHANDOVER FROM UTRANFAILURE message by a RRC

from a UE.

ISHO AMR C ll


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B
















Request



RCC: Measurement ControlNUMBER OF 3G TO 2GHANDOVER REQUESTS PERCELL

A. This measurement provides thenumber of RRM decisions for a 3GTO 2G handover

performed by a RNC, screened byreference cell from which the UEshave left the 3G

Network, when these cells arecontrolled by the considered RNC.

This measurement considers bothCS and PS handovers..

ISHO 3G -> 2G - PS Signalling Flow


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In most cases BSIC verification is not required (data interrupt as UE moves to 2G)

PS makes use of RRC: CELL CHANGE ORDER FROM UTRAN message

UE

NodeB

RNC

RRC: Measurement Report

RRC: MeasurementControl

NBAP: Radio Link ReconfigurationPrepareNBAP: Radio Link Reconfiguration Ready

NBAP: Radio Link ReconfigurationCommit

RRC: Physical Channel Reconfiguration

RRC: Physical Channel ReconfigurationComplete

NBAP: Compressed Mode Command

RRC: Measurement Report

RRC: Measurement Control GSM RSSI Measurement

ISHO triggering (5 reasons arepossible)

Initial CompressedMode Configuration

CN

RANAP: SRNS Context Request

RANAP: SRNS Context Response

RANAP: IU Release

CommandRANAP: IU ReleaseComplete

RRC: Cell Change Order from UTRAN

RANAP: SRNS Data ForwardCommand

ISHO 3G -> 2G - PS Signalling Flow


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Parameter Suggested values

HHoEcNoThreshold -12 dB

HHoEcNoCancel -9 dB

CPICH EcNo HHoEcNoCancelTime 640 ms

HHoEcNoTimeHysteresis 100 ms

EcNoFilterCoefficient 600 ms

HHoRscpThreshold -105 dBm

CPICH RSCP HHoRscpCancel -103 dBm

HHoRscpFilterCoefficient 200 ms

HHoRscpTimeHysteresis 100 ms

HHoRscpCancelTime 640 ms

UL Tx Power GsmUETxPwrThrAMR -3 dB

GsmUETxPwrFilterCoeff 10ms

GsmUETxPwrTimeHyst 320ms

DL DCH GsmDLTxPwrThrAMR +13dB

UL Quality ULQualDetRepThreshold

ISHO:Parameter Summary :


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SHO: FailuresUE RNCNode B2Node B1

RRC: MEASUREMENT REPORT (DCCH)

NBAP: RL SET-UPREQUEST

NBAP: RL SET-UP RESPONSE

ALCAP: ERQ

ALCAP : ECF

RRC: ACTIVE SET UPDATE COMPLETE(DCCH)

L1 SYNC

NBAP: SYNCH INDICATION

RRC: ACTIVE SET UPDATE(DCCH)

FP: Downlink Sync

FP: Uplink Sync

RRC: MEASUREMENTCONTROL

Admission

Control


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ALCAP: ERQ

ALCAP : ECF

RRC: ACTIVE SET UPDATE COMPLETE(DCCH)

L1 SYNC



FP: Downlink Sync

FP: Uplink Sync


AdmissionControl

NUMBER OF SUCCESSFUL RRC ACTIVE SET UPDATES

PER CELL

A. This measurement provides the number of successful RRC ACTIVESET UPDATE procedures managed by an RNC. It is incremented bythe number of cells that are added or removed, on the cells that were inthe original active set and that stay in the new active set ((ie, not addedand not removed).

C. Receipt of a RRC ACTIVE SET UPDATE COMPLETE message sentby UE to the Serving

RNC in response to an ACTIVE SET UPDATE message.

S O


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ALCAP: ERQ

ALCAP : ECF

RRC: RRC ACTIVE SET UPDATEFAILURE (DCCH)

L1 SYNC



FP: Downlink Sync

FP: Uplink Sync


AdmissionControl

NUMBER OF FAILED RRC ACTIVE SET UPDATES PER

CELL

A. This measurement provides the number of failed RRC ACTIVE SET UPDATEprocedures managed by a RNC, for each cell controlled by the RNC.

This measurement is based on two different events:.

- Receipt of a RRC ACTIVE SET UPDATE FAILURE message sent by UE to theServing RNC

in response to a RRC ACTIVE SET UPDATE message.

- Time-out expired without reception of a ACTIVE SET UPDATE COMPLETEmessage or a

ACTIVE SET UPDATE FAILURE message..


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RAB Failures


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Radio Access Bearer (RAB) Set p


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Radio Access Bearer (RAB) Set-upUE CNRNCWBTS/

Node-B

RANAP: RAB Assignment

Request :RRC RADIO BEARERSETUP

Admission Control



ALCAP: Establish Request(ERQ)

ALCAP : Establish Confirm(ECF)

FP Downlink SyncFP Uplink Sync

ALCAP : Establish Request(ERQ)

ALCAP : Establish Confirm(ECF)NBAP: RL Reconfiguration

Commit

RRC: Radio Bearer Set-up

RRC: Radio Bearer SetupComplete RANAP:RRC RADIO

BEARER SETUPmessage.

NUMBER OF SUCCESSFUL RADIO-BEARER

ESTABLISHMENTS PER CELLA. This measurement provides the number ofsuccessful radio bearer establishment procedures,

for each cell controlled by the RNC which is thereference cell.

During such a procedure, the measurement attachedto a given cell is incremented if the cellis the primarycell of the active set of the UE.

C. Reception by the RNC of a RRC RADIO BEARERSETUP COMPLETE message following the

emission of a RRC RADIO BEARER SETUPmessage.

Release of AMR Speech Call


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Release of AMR Speech CallUE RNC MGWNode B

Call Established

Iu Release Command

Iu Release Complete

RRC Connection Release

RRC Connection Release CompleteRRC Connection Release CompleteRRC Connection Release Complete

Radio Link Deletion Request

Radio Link Deletion ResponseALCAP: Release Request

ALCAP: Release ResponseALCAP: Release Request

ALCAP: Release Response

Call Released

Direct Transfer (Disconnect)Direct Transfer (Release)

Direct Transfer (Release Complete)

7

In this example the UE initiates the call release by sending the Disconnectmessage to the CS

core The network acknowledges the Disconnectmessage with a Releasemessage

The core network initiates the release of the Iu resources using the Iu Release Commandmessage


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Layer 3 messages


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Layer 3 messages

The KPI measurement conditions should be used to define exclusion areas during drivetest for acceptance of a cluster.

All failures happening in those area, that do not respect the coverage requirementsshould be discarded.

Layer 3 messages must be done in good RF conditions or you will get false reading

Good RF

RSCP equal to or greater -95dBm Ec/No equal to or greater -12dBm

Need to Define the KPI measurement (from Drive test)


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Need to Define the KPI measurement (from Drive test)

Call Setup Success (voice, circuit switched data) Successful call setup means that DL/UL Direct Transfer (CC: Alerting) message is received by

UE.

Session Setup Success (packet switched) This is related to PDP context activation.Successfully activated PDP context means that

activate PDP context accept message has been sent from RNC to UE (RRC:downlink directtransfer (SM:activate PDP context Accept)).

Call Setup Time (voice, circuit switched) Call setup delay is measured from L3 messages, starting from RRC Connection Setup

message to DL Direct Transfer (CC: Alerting) message.

Session Setup Time(packet switched)

The session setup time is the delay between the time the UE sends the data session activationrequest until GPRS attach and PDP context activation has been successfully completed.

Call Drop (voice, circuit switched) A dropped call occurs. The call will be dropped in case RRC connection release (not normal

release) message has been send from RNC to UE.

Session Drop (packet switched) Session drop rate can be defined as the number of successful PDP deactivations against

number of successful PDP activations.

Definition of Call Set-Up Success Rate (CSSR)


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UERRC: Connection Request

RRC Connection Setup phaseResource Reservation in RNC, BTS, Transmission

RRC: RRC Connection Request SetupRRC Connection Access phase

RNC waits reply from UE

RRC: RRC Connection Completed

RRC: Initial Direct Transfer cm service request

RANAP: Initial UE Message DIRECT TRANSFER (Call

Proceeding)RANAP: RAB Assignment

Request

RRC: Radio Bearer Set-up

RRC: Radio Bearer SetupComplete

RAB Connection Setup phaseResource Reservation in RNC, BTS, Transmission

RANAP: RAB AssignmentResponse DIRECT TRANSFER (Alerting)

BTS RNC CN

DIRECT TRANSFER (Connect) DIRECT TRANSFER (Connect

Acknowledge)

RAB Connection Access phaseRNC waits reply from UE

Call Set-up

SuccessRate

Call Set-up Time

Definition of the Call Completion Rate (CCR)


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UE RNC MGWNode B

Call Established

Iu Release Command

Iu Release Complete

RRC Connection Release

RRC Connection Release Complete

RRC Connection Release CompleteRRC Connection Release Complete

Radio Link Deletion Request

Radio Link Deletion ResponseALCAP: Release Request


ALCAP: Release Request


Call Released

Direct Transfer (Disconnect)

Direct Transfer (Release)

Direct Transfer (Release Complete)

DIRECT TRANSFER (Alerting)

DIRECT TRANSFER (Connect) DIRECT TRANSFER (Connect

Acknowledge)

Call DropRate

CallDuration

Definition of Session Setup TimeUE CNRNCWBTS


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INITIAL DIRECT TRANSFER (Attach Request)

Downlink Direct Transfer (Authentication & Ciphering Request)

UE already has an RRC connection

SCCP: Connection Request

SCCP: Connection Confirm

RANAP: Authentication & Ciphering Request

Security Mode Command

Uplink Direct Transfer (Authentication & Ciphering Response) RANAP: Authentication & Ciphering Response

RANAP: Security Mode Command

Security Mode Command RANAP: Security Mode Command

RANAP: Common ID

Downlink Direct Transfer: Identity Request RANAP: Identity Request

Uplink Direct Transfer: Identity Response RANAP: Identity Response

Downlink Direct Transfer: Attach Accept Direct Transfer: Attach Accept

Uplink Direct Transfer: Attach Complete Direct Transfer: Attach Complete

INITIAL DIRECT TRANSFER (Active PDP Context Request) DIRECT TRANSFER (Active PDP Context Request)

DIRECT TRANSFER (Active PDP context Accept)

RANAP: RAB ASSIGNMENTREQUESTRRC: Radio Bearer Set-up

RRC: Radio Bearer Set-up CompleteRANAP: RAB ASSIGNMENT

RESPONSERRC: Measurement Control

INITIAL UE MESSAGE (GPRS Attach)

SessionSet-upTime

Call setup failures RF issue


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Call setup failures RF issue

RF issue? Dominance

understanding wcdma kpi notes: by john r garvin

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