owo203030 wcdma ran call drop kpi and relative counters ran11 issue1.00

WCDMA RAN Call Drop KPI and Relative Counters

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Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.




Page2Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Objectives

Upon completion of this course, you will be able to:

Describe call drop counter system

Know how to calculate call drop KPI




Contents

1. Definition Of a Call Drop

2. RNC Call Drop Counter system and KPI

3. Cell Call Drop Counter system and KPI




Call Drop Signaling Procedure

Generally, the release of RABs or IU is initiated by the CN. However, in the following conditions, the RNC triggers the release.

If RNC triggers IU release or RAB release ，and the cause is:

User Inactivity

Normal Release

Successful Relocation

Network Optimization

UE Generated Signaling Connection Release

In some abnormal cases, for example, when an AAL2 link over the Iu interface is abnormal, the RNC sends a RAB RELEASE REQUEST message to the CN to trigger the release of RABs. These kinds of RNC-Triggered RAB Release are taken as call drops.




Call Drop Rate

Call drop rate in Statistic:

0.29%HSUPA Service Drop RatioCDRHSUPA

0.27%HSDPA Service Drop RateCDRHSDPA

0.34%PS Service Drop Rate [%]

0.92%VP Call Drop Rate [%]

0.48%CS AMR Call Drop Rate [%]

CDRAll Service

RNC KPIs (Average Value during N days)

ReleaseIu or RABofNumber

drops Call ofNumber Rate Drop Call =




Contents







CS Call Drop Counters (RNC)

RNC level CS call drop counters categories

Based on reasons

RF reasons

Non-RF reasons

Based on services:

AMR

CS64K

Call drop KPI should be calculated for CS and PS domain separately.

For analyze, there are call drop counters based on reasons, including RF reasons and Non-RF reasons.

For CS domain, there are call drop counters for AMR service and video call service.





Number of CS call drops due to RF

VS.RAB.Loss.CS.RF.RNC

Number of CS call drops due to Abnormal Reasons (Non RF

reasons)

VS.RAB.Loss.CS.Abnorm.RNC

Number of CS service normal releases

VS.RAB.Loss.CS.Norm.RNC

If the RNC has sent an IU RELEASE REQUEST message or a RAB RELEASE REQUEST message with the release cause of "Radio Connection With UE Lost" or "Failure in the Radio Interface Procedure", RNC measures these by RF reason counters.

After the RABs have been successfully set up, the RNC releases the related RABs if an exception occurs .These abnormal released RABs include all released RABs except the following causes: Normal Release, RF Failures . For example, the AAL2 link on the Iuinterface becomes abnormal, RNC measures these by abnormal reason counters.

After call drop , according to different services, RNC measures the counters for AMR services and video call services also.

The counters for normal RAB release are used to calculate call drop rate.




RNC Level CS Service Call Drop KPI

According to Huawei definition, the CS Service Call Drop Rate

for RNC is calculated by the following formula

s.CS.NormVS.RAB.Losm.RNCs.CS.AbnorVS.RAB.Los Cs.CS.RF.RNVS.RAB.Los m.RNCs.CS.AbnorVS.RAB.Los Cs.CS.RF.RNVS.RAB.Los

+++

Similar counters are defined for PS services based on release reason and Max bit rate.

Because of some specific UE, UE signaling trigged releases are not taken as call drop. That means “VS.RAB.Loss.PS.Abnorm.RNC” exclude UE signaling trigged releases .





Number of AMR call drops for CS AMR service

VS.RAB.Loss.CS.AMR.RNC

Number of AMR service normal releases

VS.RAB.Loss.CS.Norm.AMR (cell level counter)

Number of VP call drops for CS VP service

VS.RAB.Loss.CS.Conv64K.RNC

Number of VP service normal releases

VS.Norm.Rel.CS.Conv.RB.64 (cell level counter)

After call drop , according to different services, RNC measures the counters for AMR services and video call services.

Here , the RNC level “service normal releases” is the sum of the cell level counters.




Questions

How to calculate RNC level AMR and VP services call drop Rate ?

In your opinion, among these KPIs, which one is the most

important for you?

RNC level AMR call drop rate:

RNC level VP call drop rate:

AMRs.CS.Norm.VS.RAB.Los NCs.CS.AMR.RVS.RAB.Los NCs.CS.AMR.RVS.RAB.Los

∑+

RB.64l.CS.Conv.VS.Norm.Re 4K.RNCs.CS.Conv6VS.RAB.Los 4K.RNCs.CS.Conv6VS.RAB.Los

∑+




PS Call Drop Counters (RNC)

RNC level PS call drop counters categories

Based on reasons

RF reasons

Non-RF reasons

For PS domain, there are call drop counters for services with different typical rates.

For analyze, same as the CS counters ,there are call drop counters based on reasons, include RF reasons and Non-RF reasons.




PS Call Drop Counters (RNC)

Number of PS service call drops due to RF

VS.RAB.Loss.PS.RF.RNC

Number of PS service call drops due to Abnormal Reasons (Non

RF reasons)

VS.RAB.Loss.PS.Abnorm.RNC

Number of PS service normal releases

VS.RAB.Loss.PS.Norm

Similar counters are defined for PS services based on release reason .




RNC Level PS Service Call Drop KPI

According to Huawei definition, the PS Service Call Drop Rate

for RNC is calculated by the following formula

s.PS.NormVS.RAB.Losm.RNCs.PS.AbnorVS.RAB.Los Cs.PS.RF.RNVS.RAB.Los m.RNCs.PS.AbnorVS.RAB.Los Cs.PS.RF.RNVS.RAB.Los

+++

Similar counters are defined for PS services based on release reason and Max bit rate.

Because of some specific UE, UE signaling trigged releases are not taken as call drop. That means “VS.RAB.Loss.PS.Abnorm.RNC” exclude UE signaling trigged releases .




Contents







Contents


3.1 R99 Service Call Drop Counter System and KPI

3.2 HSPA Service Call Drop Counter System and KPI




CS Call Drop Counters (CELL)

Number of Abnormally Released RABs Triggered by RNC due to

RF Failures , RNC measure these counters in the best cell

VS.RAB.Loss.CS.RF

Number of abnormally released RABs in the best cell (Non RF

reasons)

VS.RAB.Loss.CS.Abnorm

Number of Normally Released RABs

VS.RAB.Loss.CS.Norm

After a call drop, according to the call drop reason, RNC measure these counters in the best cell. The call drop reasons include RF reasons , abnormal reasons.




Cell Level CS Call Drop KPIs

According to Huawei definition, the CS Service Call Drop Rate

for a cell is calculated by the following formula

s.CS.NormVS.RAB.Losms.CS.AbnorVS.RAB.Los s.CS.RFVS.RAB.Los ms.CS.AbnorVS.RAB.Los s.CS.RFVS.RAB.Los

+++




CS RF Call Drop Counters (CELL)

Number of Abnormally Released RABs Triggered by RNC due to RF

Failures “VS.RAB.Loss.CS.RF” includes:

Number of CS domain RAB releases triggered by the RNC due to RLC reset

VS.RAB.Loss.CS.RF.RLCRst

Number of CS domain RAB releases triggered by the RNC due to Uplink

Synchronization Fail

VS.RAB.Loss.CS.RF.ULSync

Number of the CS domain RAB releases triggered by the RNC due to

Failure in the Radio Interface Procedure

VS.RAB.Loss.CS.RF.UuNoReply

RF call drop may be caused by several reasons: RLC layer resetPhysical layer Uplink Synchronization Fail Failure in the Radio Interface Procedure

Based on these reasons, three counters are defined.




CS Abnormal Call Drop Counters (CELL)


Non-RF Failures “VS.RAB.Loss.CS.Abnorm” include:

Cause of "O&M Intervention"

VS.RAB.RelReqCS.OM

Cause of "RAB pre-empted"

VS.RAB.RelReqCS.RABPreempt

Cause of “CELL Congestion”

VS.RAB.Loss.CS.Congstion.CELL

Cause of “Iu Interface AAL2 Link Failure”

VS.RAB.Loss.CS.Aal2Loss

Cause of "O&M Intervention“: by LMT, any user or service can be released manually.

Cause of "RAB pre-empted“ and “CELL Congestion” are related to load control algorithm.

Cause of “Iu Interface AAL2 Link Failure” is related to the Iu transmission.




PS Call Drop Counters (CELL)


RF Failures

VS.RAB.Loss.PS.RF

Number of Abnormally Released RABs Triggered by RNC (Non

RF reasons)

VS.RAB.Loss.PS.Abnorm

Number of Normally Released RABs

VS.RAB.Loss.PS.Norm

After a call drop, according to the call drop reason, RNC measure these counters in the best cell.

The call drop reasons include RF reasons , abnormal reasons.




Cell Level PS Call Drop KPIs

According to Huawei definition, the PS Service Call Drop Rate

for a cell is calculated by the following formula

s.PS.NormVS.RAB.Losms.PS.AbnorVS.RAB.Los s.PS.RFVS.RAB.Losms.PS.AbnorVS.RAB.Los s.PS.RFVS.RAB.Los

+++





Number of Abnormally Released RABs Triggered by RNC due to RF

Failures “VS.RAB.Loss.PS.RF” include:

Number of PS domain RAB releases triggered by the RNC due to RLC reset

VS.RAB.Loss.PS.RF.RLCRst

Number of PS domain RAB releases triggered by the RNC due to Uplink

Synchronization Fail

VS.RAB.Loss.PS.RF.ULSync

Number of the PS domain RAB releases triggered by the RNC due to

Failure in the Radio Interface Procedure

VS.RAB.Loss.PS.RF.UuNoReply

RF call drop can be caused by several reasons:

RLC layer reset

Physical layer Uplink Synchronization Fail

RRC layer procedure failure

Based on these reasons, three counters are defined.

Because of PS traffic and signaling are configured with RLC AM ,so “RLC reset” for PS include SRB reset and TRB reset, measured by “VS.RAB.Loss.PS.SRBReset” and “VS.RAB.Loss.PS.TRBReset”.






Abnormal Failures “VS.RAB.Loss.PS.Abnorm” include:

Cause of "O&M Intervention"

VS.RAB.RelReqPS.OM

Cause of "RAB pre-empted"

VS.RAB.RelReqPS.RABPreempt

Cause of “CELL Congestion”

VS.RAB.Loss.PS.Congstion.CELL

Cause of “GTPU Failure ”

VS.RAB.Loss.PS.GTPULoss

The counters for abnormal failures are similar with the CS counters.




Questions

How to calculate Cell level AMR and VP services call drop Rate ?

In these call drop counters, which one may be caused by

missing neighbors?

Can you tell the procedure of the call drop caused by missing

neighbors?

Missing neighbors may cause RF call drops.




Contents


3.1 R99 Service Call Drop Counter System and KPI

3.2 HSPA Service Call Drop Counter System and KPI




Cell HSDPA Call Drop Counters

Number of Abnormally Released HSDPA Services due to RF

VS.HSDPA.RAB.Loss.RF

Number of Abnormally Released HSDPA Services due to Non-RF

VS.HSDPA.RAB.Loss.Abnorm.NonRF

Number of Normally Released HSDPA Services

VS.HSDPA.RAB.Loss.Norm

If the RAB is set up for the HSDPA service, the RNC measures the items in the HSDPA cell that the UE camps on after HSDPA call drop.

The call drop reasons could be RF or abnormal (Non-RF) reasons.

Because of some specific UE, UE signaling trigged releases are not taken as call drops, these releases are included in “VS.HSDPA.RAB.Loss.Norm”




Cell HSDPA Call Drop Counters

Number of Abnormally Released HSUPA Services

VS.HSUPA.RAB.Loss.Abnorm

Number of Normally Released HSUPA Services

VS.HSUPA.RAB.Loss.Norm

“VS.HSUPA.RAB.Loss.Abnorm” , this measurement item takes statistics of the number of all HSUPA RABs abnormally released by the RNC in a cell.




Cell Level HSPA Service Call Drop KPIs

Cell level HSDPA service call drop rate :

Cell level HSUPA service call drop rate :

rmAB.Loss.NoVS.HSDPA.Rnorm.NonRFAB.Loss.AbVS.HSDPA.R AB.Loss.RFVS.HSDPA.Rnorm.NonRFAB.Loss.AbVS.HSDPA.R AB.Loss.RFVS.HSDPA.R

+++

rmAB.Loss.NoVS.HSUPA.RnormAB.Loss.AbVS.HSUPA.RnormAB.Loss.AbVS.HSUPA.R

+




Discussion

HSPA state may be a temporary state of a service, that means,

during the service, UE may be switched to Cell_DCH or

Cell_FACH state.

If a UE service is normally released after switching to Cell_FACH

or Cell_DCH state, then this release will not trigger the

“VS.HSxPA.RAB.Loss.Norm” .

What is the effect of this?

How to solve it?



Thank youwww.huawei.com

owo203030 wcdma ran call drop kpi and relative counters ran11 issue1.00

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