02 RN31572EN40GLA0 Performance Monitoring

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For internal use

2013 Nokia Solutions and Networks. All rights reserved. RN31572EN40GLA0

3G RANOP RU40 Performance Monitoring

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For internal use


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For internal use


Module Objectives

At the end of the module you will be able to:

Describe 3G RAN performance monitoring hierarchy

Describe the mechanisms for call analysis related to

Busy hour

Paging, RRC and RAB setup and access failure

Session setup failure for NRT and HSPA

SHO, ISHO, relocation and SCC failure

RAB, DCH, radio link and HSPA drop

List possible reasons for failures and improvement activities

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For internal use


Performance Monitoring

KPI analysis hierarchies

Call setup (busy hour, paging, RRC, RAB, PS session)

Call drop (RAB, DCH, radio link)

Mobility (SHO, ISHO, relocation)

HSPA setup

HSPA drop

HSPA mobility (SCC, HSUPA SHO)

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KPI analysis hierarchy

Available data can be classified as in the figure below

There is no point to look at detailed data if the bigger picture is not clear

More details

More

understanding

More

complexity

More cost and

time in

acquisition

KPIs (e.g. CSSR, CDR by Traffica)

Service level

(RRC / RAB / PS session)

SHO SCC IFHO ISHO

Signaling (RRC, NBAP, RNSAP, RANAP)

Subscriber trace, ICSU logs (NSN internal use only)

Cell resource (TCP, RTWP, codes)

BTS / Iub / RNC resources

Interface trace and probe statistics

Performance data hierarchy

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Availability of neighbor cell

Missing adjacency has impact both

on serving and neighboring cell

Iub

WBTS

KPIs and counters

detect faults at different layers

- Handover performance

- Traffic

- Cell resources

- Iub Signaling

- Cell availability

- Failures due to Radio, BTS, transport


Cell and cluster specific performance

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Complexity of performance data increases with number of cells in the network

Almost all data have to be analysed at cell or WBTS level

But evaluation over time and comparison between large areas (cities, RNCs) still required

Cell Availability

Failures due to Radio, to BTS, to transport

Handover Performance

Traffic

Cell Resources

Iub Signaling

Some data better analysed at RNC level

Here only time evolution and RNC comparison are useful

Failures due the RNC, Iu, Iur

NAS and relocation Signaling

Cell and cluster specific performance

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For internal use


Too big lists of results will irritate consultants

Main impacts must be visible and manageable for hands on task

Different tables of different data warehouse must be verifiable

Data / KPI benchmark should be easy

List top 10-20 worst cells

E.g. those of highest CDR


Analysis priority

Cell ID CDR/%

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Few bad cells (here 3 of 90)

cause already about of all

drops

Quick fault diagnostics due to priority of worst cells


Highest analysis priority for cells of highest failure rate

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For internal use



Either total number of failures or failure rate (%) can be used

Total number of failures directly proportional to loss of income for operator

Cell with high failure rate might not have high priority, if total traffic is low

To reach more uniform performance

Consider statistics with some periodicity large enough (e.g. per month)

Consider filter requesting minimum number of attempts / failures per cell depending on network traffic (reduce statistical fluctuations)

Highest analysis priority for cells of highest failure rate

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HSPA setup

HSPA drop


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MAX (CS_VOICE_CALL_DL + CS_DATA_CALL_CONV_DL +

CS_DATA_CALL_STREAM_DL + PS_DATA_CALL_CONV_DL +

PS_DATA_STREAM_DL + PS_DATA_CALL_INTERA_DL +

PS_DATA_CALL_BACKG_DL)

Busy hour on the basis of traffic sum

RT and NRT summed every hour

Each counter represents product bit rate * allocation duration

Hour with maximum value taken as BH

0 24 h 12 h

Traffic sum RT / NRT

e.g. by NetAct

1 h

1 h

1 h

1 h

BH

CSSR

CDR

Call setup busy hour

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Busy hour on the basis of data volume (example on RNC level)


Time / h

Data volume / GByte

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Voice, R99 NRT and HSPA peak traffic can happen at different times

Blocking of specific service not necessarily happening during BH based on traffic sum

In loaded networks CSSR taken at weekly BH is relevant

Failures originate mostly from congestion (Iub, BTS HW (CEs), radio)

Target call blocking probability designed for BH

In unloaded networks CSSR taken at weekly BH may not yield the hour with highest blocking (NRT traffic is taken into account as well as RT one)

On cell level needed to compute BH statistic based on absolute time period (e.g. 16-18h every day)

Daily data may not be accurate enough due to big variations of results (ongoing operation, system failures, sleeping cells, alarms etc.)

Busy hour daily or weekly

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IuB

Air Interface WBTS HW Resources Transport

UL interference

DL transmisson power

DL Codes

FSP/ WSP capacity (N*) E1 capacity / AAL2 or IP

RLC/MAC

DSP processing

RNC

During call setup (RRC, RAB, PS session)

several resource areas are checked and

physical / logical resources allocated

Resource checks

Call setup bottlenecks

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UE BS RNC CN

Paging

Paging type 1

RRC connection request

Paging types

Call setup paging

UE in RRC idle

E.g. incoming RT or NRT call

Paging

Paging type 1

RRC cell update

Paging

Paging type 2

RRC cell update

UE in Cell_PCH or URA_PCH

E.g. inactive NRT RAB and incoming voice call

UE in Cell_FACH or Cell_DCH

E.g. active NRT RAB and incoming voice call

Incoming data

Paging type 1

RRC cell update

UE in Cell_PCH or URA_PCH

NRT RAB inactive, but still data arriving from core network

RNC pages UE to take the data

CN

in

itia

ted

R

NC

in

itia

ted

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For internal use


Paging channels

Call setup paging

PCH with 8 Kbit/s

Standard implementation

With 80 bit per page message up to 100 pages / s supported per cell

Has SF256

Default power setting 5 dB below CPICH (28 dBm = 0.63 W, 3% of maximum power of 20 W cell)

PCH with 24 Kbit/s

Optionally available since RU20

With 80 bit per page message up to 300 pages / s supported per cell

Has SF128 Maximum of 14 codes for HSDPA, if additionally HSUPA with 2ms TTI in use

Default power setting 2 dB below CPICH (31 dBm = 1.26 W, 6% of maximum power of 20 W cell)

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Code tree with 24K PCH

Call setup paging

Cch,256,0

Cch,256,1

Cch,256,2

Cch,256,3

Cch,128,4

Cch,128,5

CPICH

P-CCPCH

AICH

PICH Cch,64,1

Cch,256,14

S-CCPCH 1 FACH

E-AGCH 10 ms

HS-SCCH

E-HICH & E-RGCH

S-CCPCH 2 PCH with 24 K

Cch,128,6

Cch,16,0

Cch,256,15

E-AGCH 2 ms

HSUPA with 2ms TTI requires additionally fractional DPCH

For F-DPCH no place on first sub-tree any more

But loss of 1 HSDPA code not critical

Probability, that air interface allowes 15 codes, usually less than 1:1000

Loss of 3% of maximum cell power by 24K PCH much more significant

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Paging monitoring

Call setup paging

Check number of page messages forwarded to PCH

(M1006)

Paging Type 1 Att CN Orig

Messages originating from core network

Paging Type 1 Att RNC Orig

Messages originating from RNC

Check number of pages transmitted by PCH

(M1000)

Ave PCH Throughput /

PCH Throughput Denom 0 =

Throughput on PCH

Throughput / 80 Bit =

Number of pages per second

Difference

Pages lost by PCH blocking

Check number of responses to paging

(M1006)

Difference

Low air interface performance

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For internal use


Paging optimization

Call setup paging

PCH blocking

Standard rule: If average throughput < 70% of maximum throughput than blocking rate < 1 %

In case of too high blocking rate

1) Instead of 1 S-CCPCH (shared by FACH and PCH) 2 S-CCPCH (one

for FACH, one for 8K PCH)

2) Instead of 8K PCH 24K PCH

3) Reduce size of LA and RA

No response to paging

Check DL performance (RSCP, Ec/Io, S-CCPCH power settings) UE might not be capable to decode page messages

Check UL performance (RTWP, RACH procedure parameter settings) response of UE might not arrive at BTS

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RRC connection setup RAN resources reserved for signaling connection between UE and RNC

RRC access Connection between UE and RRC

RRC active UE has RRC connection

If dropped, also active RAB dropped

RAB setup Attempts to start call

RAB setup access

Connection between UE and core

RAB active phase UE has RAB connection

CSSR affected if any of the following

events takes place

RRC Connection Setup Fail

RRC Connection Access Fail

RAB Setup Fail

RAB Setup Access Fail

Setup

Complete

Access

Complete

Active

Complete

Setup Access Active

Attem

pts

Setup failures (blocking)

Access failures

Access

Active

Release

Active

Failures RRC Drop

Success

Phase:

RRC and RAB

Call setup - phases

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[RACH] RRC Connection Request

UE Node B RNC

ALCAP ERQ

NBAP RL Setup Request

[DCH] RRC Connection Setup Complete

L1 Synchronisation

Start TX/RX

Start TX/RX

[FACH] RRC: RRC Connection Setup

NBAP RL Setup Response

AC to check to accept or reject RRC

Connection Request

ALCAP ECF

NBAP Synchronization Indication

RRC Connection Setup

phase

RRC Connection

Access phase

RRC Connection Active phase

Allocation of UTRAN

resources

Waiting for UE reply

M1001C0

Counter

M1001C1

M1001C8

Three phase for RRC

Call setup successful RRC establishment Signaling and trigger

M1001C8

M1001C0

= successful RRC

establishment

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For internal use


BTS UE RNC CN

RRC connection Request

RRC connection Setup

RRC SETUP phase

(Resource Reservation in RNC)

RRC ACCESS phase

(RNC waits for Reply from UE)

RRC connection Setup Complete

RRC: Initial Direct Transfer

RANAP: Initial UE Message

RANAP: Iu Release Command

UE-CN Signaling

(E.g. RAB Establishment and Release)

RRC: RRC connection Release

RRC: RRC connection Release Complete

Release RRC resources in RNC, BTS,

Transport

RRC ACTIVE phase

RRC ACCESS fails if

UE does not reply to RRC CONNECTION SETUP message with RRC

CONNECTION SETUP COMPLETE message within given time

BTS reports radio link synchronisation failure

RNC internal failure occurs

RRC SETUP fails if some of needed resources (RNC, BTS, air,

transport) are not available

When RRC setup failure occurs the RNC sends RRC CONNECTION

REJECT message to UE

RRC ACTIVE fails when an interface related (Iu, Iur , Iub, or radio) or

RNC internal failure occurs, and the failure causes the release of the

RRC Connection

When an RRC active failure occurs, the RNC send RANAP IU

RELEASE REQUEST to all involved CNs and waits for RANAP IU

RELEASE COMMAND message(s)

RRC ACTIVE release cause NOT indicating a drop can be either

Normal release

IFHO / ISHO

Relocation

Pre-emption

Call setup failure of RRC establishment Failure causes

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For internal use


Sites OK ?

Serving and neighbor cells availability Alarms/Tickets

Setup /Access

Yes

Setup /Access

Setup Failure Cause?

Capacity Optimisation

BTS/TRANS/

Frozen BTS UL/DL Interference (DL codes)

AC

Troubleshooting RNC

RF Optimisation

Top (N) RRC Setup and Access failures

Top (N) RAB Setup and Access or PS Setup failures

Coverage/ Interference

Setup

Setup

Interference

Coverage

3G cell at inter-RNC border ?

Relocation troubleshooting

Yes

NO

Access

Access

Call setup analysis process Flow chart for RRC / RAB

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For internal use


Call setup failure

RRC or RAB setup failure can be due to

Coverage or interference

Capacity AC for radio capacity issues (UL load, DL load, DL spreading codes)

BTS for channel element (FSM or WSP) capacity issues

TRANS for Iub capacity issues

RNC problem RNC fault

Failure of incoming relocation

Failure overview

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For internal use


Call setup RRC setup failure Failure cause example

Dominating failure cause during RRC

setup due to BTS

Check e.g. channel cards

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For internal use


RRC setup failure analysis

RRC_CONN_STP_FAIL_AC

Check UL interference, DL power and code occupancy (M1000)

UL power spikes Disable UL admission control if number of failures is critical

RRC_CONN_STP_FAIL_BTS

Evaluate NBAP counters (radio link setup failures) for troubleshooting BTS resources (M1005)

Check BTS configuration in terms of WAM and CE allocation use channel element counters in order to evaluate lack of channel elements (M5001)

Expand the capacity or decrease the traffic offered to the site

In case BTS is not responding delete and re-create COCO

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RRC setup failure analysis

RRC_CONN_STP_FAIL_TRANS

Evaluate number of reconfiguration failures due the transmission

Check COCO configuration

Use AAL2 Mux in case of two WAM

Expand the capacity or decrease the traffic offered to the site

RRC_CONN_STP_FAIL_RNTI ALLO FAIL

RNC decides to reject RRC connection request due to RNTI allocation

failure caused by RRMU overload

RRC_CONN_STP_FAIL_RNC

Typically RNC fault or incoming SRNC relocation failure

Requires ICSU log tracing if no RNC fault or SRNC relocation problem

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For internal use


Network access of UE via Cell_FACH

RACH and FACH transport channels used for call setup

Call setup on CCH is faster than on DCH

All time consuming procedures move to Cell_DCH

Depending on Ec/Io and CCH load/power status, UE moves to Cell_DCH

RRC IdleRRC Idle

no UE Location Information

in UTRAN

only LAI / RAIin CN

no data transfer possible

RRC Connectionestablishment via

RACH/FACH

signaling

New

Establish

/ Release

RRC

Connection

Cell_PCH UEs cell known UE to be paged (DRX functionality PICH)

Cell_FACH common channel allocated (FACH, RACH, CPCH, DSCH)

UEs cell known

Cell_DCH DCH allocated UEs cell known

URA_PCH similar to Cell_PCH no Cell Update, but URA Update

Connection modeConnection mode

With I-phone

not possible

Quicker access

via RACH/FACH

for UE

Common channel setup

Call setup RRC setup optimization

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For internal use


UE BS RNC CN

CM service request

RAB ass. req.

Radio Bearer Setup

Radio Bearer Setup Complete

RAB ass. resp.

RAB SETUP PHASE

RAB ACCESS PHASE



RRC Connection Request

RRC Connection Setup

RRC Connection Setup Compete

Security procedures

RRC SETUP PHASE

RRC ACCESS PHASE

No RL setup

No CAC

No AAL setup

No RL setup

No CAC

No AAL setup

Cell_FACH state used for subsequent signaling

UE enters Cell_FACH e.g. for pure signaling procedure like LA update

Traffic Volume Measurements performed in Cell_FACH state

Cell_DCH used once channel type switching selected DCH or HSPA transport channel

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For internal use


Allocation of RACH / FACH or DCH based on establishment cause received from UE (22 causes)

Available SRB bit rate on DCH 3.4 kbps or 13.6 kbps configurable by parameter

RACH and FACH load continuously monitored in RNC (too high load prevents common channel setup default = 75% load)

Air interface quality (CPICH Ec/Io) criteria has impact on common channel allocation (default Ec/Io -8 dB required)



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For internal use


L1 Synchronisation

NBAP: Synchronisation Indication

RRC Connection Setup Complete X

UE BTS RNC

X No L1 synchronization

Failure due to radio

L1 Synchronisation

X UE BTS RNC

No response from UE

Failure due to UE

Cell reselection or directed RRC setup (no error)

Call setup RRC access failure Failure definitions

NBAP: Synchronisation Indication

RRC Connection Setup Complete

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For internal use


Call setup RRC access failure Failure cause example

Dominating failure cause for RRC access due to radio

But for a few days dominating failure due to RNC

Check e.g. ICSU and DSPs

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For internal use


RRC access failure analysis

RRC_CONN_ACC_FAIL_RADIO

Dominant failure cause

Perform drive test to detect if lack of UL or DL coverage

UL coverage tune cell dominance if cause is UL interference

DL coverage tune S-CCPCH power if UE does not receive RRC connection setup message

RRC_CONN_ACC_FAIL_MS

UL coverage tune cell dominance (CPICH) in order to balance UL and DL (if UL interference not the cause

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For internal use


Quicker access due to post verification of QoS

If CPHY-Sync-IND primitive quality sufficiently

good, UE starts 70 ms quicker

Faults due to radio will decrease, faults due to

UE (post verification) will increase

Node B starts transmitting

Post verification check

40 ms window

UE starts transmitting with Post Verification

UE starts receiving,

mobile is listing on FACH

UE stops transmitting if verification check fails

10 ms radio frames

UE L1 collects 40 ms

of quality

measurements

The total delay before UE starts UL

transmission is reduced by 70 ms.

40 ms window

50 ms window

UE starts transmitting

without Post Verification

40 ms window

40 ms window

40 ms window

RRC Connection Access phase

[RRC Connection Setup (FACH)

Fast Layer 1 synchronization

Call setup RRC access optimization

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For internal use


Call setup successful RAB establishment Signaling and trigger

UE BS RNC CN

CM service request

RAB ass. req.

RL rec. prepare

RL rec. ready

AC

RNC Iub internal resources

AAL2

CAC AAL2 sig. ERQ

RAB_STP_ATTEMPTS

Radio Bearer Setup

Radio Bearer Setup Complete

AAL2 sig. ERQ

AAL2 sig. ECF

RAB ass. resp. (success)

RAB_STP_COMPLETE

RAB SETUP PHASE

RAB_ACC_COMPLETE

RAB ACCESS PHASE

Iu CS

RNC internal resources

AAL2

CAC

AAL2 sig. ECF

RAB ass. resp. (failure cause, if resources missing)

Exception: release of the RAB during SETUP or ACCESSE phase

M1001C66 RAB STP ATT

M1001C115 RAB ACC CPL

RL rec. commit M1001C73 RAB STP CPL

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For internal use


Call setup RAB setup failure Failure cause example for voice

Many CS RAB setup failure causes due to AC, Iub and BTS

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For internal use


RAB setup failure analysis

RAB_STP_FAIL_XXX_AC (not done in case of NRT RAB)

Check UL interference, DL power and code occupancy

Evaluate AMR voice and PS 64K code congestion

RAB_STP_FAIL_XXX_BTS

Evaluate NBAP counters (radio link reconfiguration failures) for troubleshooting BTS resources (M1005)

Check BTS configuration in terms of WAM and CE allocation use channel element counters in order to evaluate lack of channel elements (M5001)

Expand capacity or decrease traffic offered to the site

In case BTS is not responding delete and re-create COCO

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For internal use


RAB setup failure analysis

RAB_STP_FAIL_XXX_TRANS

Evaluate number of reconfiguration failures due the transmission

Check COCO Configuration

RAB_ACC_FAIL_XXX_MS

Evaluate cell resources TCP and RTWP (for example high uplink interference)

Check radio bearer reconfiguration failure ratio

RAB_ACC_FAIL_XXX_RNC



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For internal use


Call setup RAB access failure Failure cause example for voice

Many CS RAB access failure causes due to UE

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For internal use


RAB access failure analysis

RAB_ACC_FAIL_XXX_MS

Evaluate cell resources TCP and RTWP (for example high uplink interference)

Check radio bearer reconfiguration failure ratio

RAB_ACC_FAIL_XXX_RNC



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For internal use


Call setup successful PS session establishment Signaling and trigger

UE BS RNC

Capacity request

RL rec. prepare

RL rec. ready

AC

RNC Iub internal resources

AAL2

CAC AAL2 sig. ERQ

Radio Bearer Reconfig.

Radio Bearer Reconfig. Complete

AAL2 sig. ECF

RL rec. commit

PS session SETUP PHASE

PS session ACCESS PHASE

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For internal use


Call setup PS session setup failure Failure cause example

Fault analysis completely analog to RRC and RAB

Many PS RAB setup failure causes due to UE and AC

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For internal use







HSPA setup

HSPA drop


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For internal use


Top (N) drops

Serving and neighbor cells availability Alarms/Tickets

Configuration and parameter audit

SHO Success

Rate < 90%?

Conf OK ?

Site OK ?

ISHO Failures

Iur performance Investigation Iur

Audit adjacent sites for alarms, availability,

configuration and capacity

Traffic neighbor performance (use SHO success per adjacency

counters to identify badly performing neighbors) and map

3G Cell at RNC

border?

NO

YES

New site ?

Analyse last detailed radio measurements

RF and IFHO neighbor optimisation

No cell found ratio

>40 %

ISHO Success

Rate < 90%

RF and ISHO neighbor optimisation

3G cell

covers over a coverage hole

?

3G cell at inter-RNC border ?

Wrong reference clock (10MHz tuning)

No cell found ratio > 90 % and enough

ADJG

2G Cell Doctor

2G Investigation TCH blocking or

TCH seizure failure (interference)

NO

YES

YES

YES

NO

YES

NO

YES

YES

SHO

ISHO

Call drop analysis process 1/2 Flow chart for RAB

No SHO See next slide

No SHO triggered??? Fragmented Cell! Forgotten Neigbours! Temporary Solution DSR;

Solution Fragmented Cell find Reflection or antenna side lobe change Antenna tilt or azimuth;

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For internal use


Call drop analysis process 2/2

No SHO Check adjacencies

Not OK

Corrrect the adjacencies list (Include forgotten neighbors)

OK

Check of cell fragmentation

change Antenna tilt or azimuth

Temporary solution: activate DSR

YES

Check SHO parameters No

No SHO triggered??? Fragmented Cell! Forgotten Neigbours! Temporary Solution DSR;

Solution Fragmented Cell find Reflection or antenna side lobe change Antenna tilt or azimuth;

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For internal use


Call drop analysis Failure cause example for voice

Many CS RAB drop causes due to radio and transmission

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For internal use


Call drop analysis Failure cause example for PS

Many PS RAB drop causes due to UE and radio

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For internal use


Call drop analysis 1. Check high call drop cells and its neighboring cells for any fault alarms

2. Generate call drop root cause distribution and check for main contributors (radio, BTS, Iub, Iur, RNC, Iu, MS)

3. Check SHO if success rate < 90% (leads to radio link failure)

Check if cells are at RNC border (check Iur capacity and SRNC relocation problem)

Detect badly performing neighbors using SHO success rate per adjacency counters (M1013)

High incoming HO failure rate from all adjacencies check sync alarms

Assess neighbor list plan and do visualization check with map

Evaluate HO control parameters and trigger thresholds

4. Check ISHO KPI if RT ISHO < 90% or NRT < 80% (leads to radio failure)

Check missing neighbors (M1015)

Check GSM frequency plan, RNC and MSC database consistency

Check alarm of reference clock in 3G or in 2G

Check 2G TCH congestion

Check RRC drop during ISHO RT / NRT

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For internal use


Call drop analysis 5. Look for DL or UL path loss problem if RAB drop due to radio dominates

Check UE lost counters (active L1 synchronization failure) to check UL/DL path loss problem

Check active set update failure rate (with cause no response from UE)

Map radio failures with RL power and CPICH related parameters (CPICHToRefRABOffset, PTxDPCHMax)

Check call reestablishment timer (T315)

Check Ec/Io distribution for bad coverage issue (M1007)

6. Check core network parameter setting if RAB drop due to Iu

Check SCCP signaling (MSC / SGSN, RNC, IuCS / IuPS)

7. If high RAB drop due to BTS

Check for any BTS faulty alarm (e.g. 7653 cell faulty alarm)

If no alarms, COCO detach/attach

8. If high RAB drop due to MS

Check physical channel reconfiguration failure rate (IFHO, ISHO, code optimization)

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For internal use


Call drop analysis Example for trace of individual dropped call (possible with MEGAMON)

UE does not find SHO neighbor

Event 1F due to RSCP

UE enters compressed mode

But does not find GSM neighbor either

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For internal use


RT

If communication between UE and network interrupted, this will trigger RAB drop

NRT

Interrupted communication between UE and network will not trigger immediately RAB drop

Network tries to shift UE to Cell_FACH state, i.e. tries to keep RAB running

RT and NRT

Soft drop - DCH

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For internal use


Failure cause example

Soft drop - DCH

Two drop cause counters only

Radio

Other

Majority of DCH drops still due to radio

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For internal use


RLSHOFORSUCCSETUPRL

RLFIRSTFORSUCCSETUPRL

SRNCSHOSUCCADDBRANCHRL

FAILSYNRLACTSRNCSHODELACTLOSTUL

_____

_____

_____

________

RL setup due to softer HO

RL deletion due to synchronization failure

Downlink radio link failure results in UL synchronization loss since the UE stops transmitting

Soft drop radio link failure

BTS looses synchronization with UE and cannot re establish it within specified time

Compare number of radio links deletions due to synchronization failure with total number radio link setup processes

In SHO radio link failure downgrades coverage only, but does not trigger immediately DCH or even RAB drop

Definition

RL setup due to initial request

RL setup due to soft HO

The counter DEL_SHO_SRNC_ACT_RL_SYNC_ FAIL measure the number of Radio link deletions on SRNC side due to an active radio link synchronisation failure. If a BTS loses synchronisation on an active RL and is not able to re-establish synchronisation during the allowed time.

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For internal use


Soft drop - radio link failure Failure example RL deletion by SRNC and DRNC (with OSS data)

> 50 % abnormal deletions

< 20 % abnormal deletions Each point represents one cell

Black = RL deletion by SRNC

Red = RL deletion by DRNC

High number of abnormal radio link deletions by DRNC

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For internal use







HSPA setup

HSPA drop


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For internal use


SHO successful softer HO Signaling and trigger

UE BS RNC

Measurement report 1A or 1C

RL addition request

RL addition response

AC

BTS resources needed

But no Iub resources (no CAC)

Active set update

Active set update complete

SETUP PHASE

ACCESS PHASE

If problem, check radio link addition failure causes (M1005)

If problem, check air interface performance

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For internal use


SHO successful soft HO Signaling and trigger

UE BS RNC

Measurement report 1A or 1C

RL setup request

RL setup response

AC

Active set update

Active set update complete

SETUP PHASE

ACCESS PHASE

AAL2 sig. ERQ

AAL2 sig. ECF

BTS resources needed

And Iub resources needed (CAC)

If problem, check radio link setup failure causes (M1005)

If problem, check air interface performance

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For internal use


SHO Overhead Concept and counters

Indicates size of SHO area

If too small, SHO might fail

If too big, capacity is wasted

Counter for calculation of overhead

Consider the time, a call stays in an active set of 1 / 2 / 3 cells, both for RT and NRT services

ONE_CELL_IN_ACT_SET_FOR_(N)RT

TWO_CELL_IN_ACT_SET_FOR_(N)RT

THREE_CELL_IN_ACT_SET_FOR_(N)RT

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For internal use


Call setup in cell A.

Cell A Cell B

Cell A Cell BCell A Cell B


After 40sec Event 1A (addition): Active Set has changed.

(CellA) ONE_CELL_IN_ACTIVE_SET incremented + 40sec

After 60sec Event 1B (deletion): Active Set has changed.

(Cell A) TWO_CELL_IN_ACTIVE_SET incremented +60sec

(Cell B) TWO_CELL_IN_ACTIVE_SET incremented +60sec


After 20sec Call release.

(Cell B) ONE_CELL_IN_ACTIVE_SET incremented + 20sec

SHO Overhead Concept and counters

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For internal use


cell A

cell B

NRTRTSETACTINCELLTHREE

NRTRTSETACTINCELLTWO

NRTRTSETACTINCELLONE



NRTRTFORSETACTINCELLONE

/_____

/_____

/_____

3/_____

2/_____

/______

Factors 1/2/3 = number of

radio links

Total time during which all calls are

running with different AS size

E1A CPICH E1B CPICH

Offset 4dB Offset 6dB

SHO area

KPI shall give average

number of radio links

during a call

Total time of

all calls

SHO Overhead Cell level

63

For internal use


Example: RNC area with 3 cells A, B and C

Cell A: 20 s active alone, 10 s with B, 10 s with C, 5 s with B + C

(20 s alone, 20 s with 2 cells, 5 s with 3 cells)

Cell B: 30 s active alone, 10 s with A, 5 s with C, 5 s with A + C


Cell C: 25 s active alone. 10 s with A, 5 s with B, 5 s with A + B


Cell level results

Cell A: Average AS size = (20x1 + 20x2 + 5x3) / (20 + 20 + 5) = 1.67 (67% overhead)

Cell B: Average AS size = (30x1 + 15x2 + 5x3) / (30 + 15 + 5) = 1.50 (50% overhead)

Cell C: Average AS size = (25x1 + 15x2 + 5x3) / (25 + 15 + 5) = 1.56 (56% overhead)


Too big SHO overhead indicated

64

For internal use


Cell level formula gives too high KPI value

Reason:

If e.g. A and B are active, during this time a call is counted both in A and

B, i.e. two times

If e.g. A. B and C are active, during this time a call is counted in A, B and

C, i.e. three times

cell A

cell B

Counted in

cell A only Counted in cell A and

cell B

If cell A active together

with B

than cell B also active

together with cell A


65

For internal use


cell A

cell B

3//_____

2//_____

/_____

/_____

/_____

/______



NRTRTSETACTINCELLONE



NRTRTFORSETACTINCELLONE

KPI compares effective

number of calls with

number of radio links

Call belongs

to cell A only

Call belongs half to cell A and half to cell B

Denominators 1/2/3:

Call with 1 radio link

Belongs completely to its single

active cell

Cell with 2 radio links

Half the call belongs to each

active cell

Cell with 3 radio links

One third of the call belongs to

each active cell

SHO Overhead RNC level

RT/NRT means sum of counters for RT and NRT e.g. M1007C0+M1007C19 for ASS=1

66

For internal use


Example: RNC area with 3 cells A, B and C

Cell A: 20 s active alone, 10 s with B, 10 s with C, 5 s with B + C

Cell B: 30 s active alone, 10 s with A, 5 s with C, 5 s with A + C

Cell C: 25 s active alone. 10 s with A, 5 s with B, 5 s with A + B

RNC level results

Cell A, B and C altogether

75 s active alone

50 s with second cell

15 s with third cell

Average AS size = (75 + 50 + 15) / (75/1 + 50/2 + 15/3) = 1.33 (33% overhead)

RNC level KPI gives about half the overhead only than the cell level KPI!!

SHO Overhead RNC level

Realistic SHO overhead indicated

67

For internal use


SHO Overhead RNC level example

Typical target for SHO overhead 40%

68

For internal use


SHO per adjacency Concept and counters

SHO attempts per adjacency

No attempts to distant cell might be removed from neighbor list

No attempts to nearby cell check whether SC of ADJS is declared correctly in RNC data base

No attempts to inter-RNC cell check whether RNC data bases are consistent with each other (e.g. SC declarations)

Very few attempts to nearby cell check user distribution and propagation conditions

Very few attempts in general check addition window setting

Too many attempts to specific neighbor check user distribution and pilot pollution

Too many attempts in general check addition window setting

69

For internal use


HO_ATTTRA_FREQ_SSHO_ADJ_IN

HO_COMPLTRA_FREQ_SSHO_ADJ_IN _RNCs_per_ADJSSHO_succes

SHO per adjacency Concept and counters

SHO success per adjacency

High failure rate (several 10%) besides RL setup / addition failures and air interface performance check for SC clash

100% failure rate to intra-RNC cell check for HW faults

100% failure rate to inter-RNC cell check for inconsistency between RNC and core network data base (e.g. CI, LAC and RAC declarations)

Attempt and success per adjacency monitored by AutoDef SHO

counters (M1013)

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For internal use


ISHO successful procedure Signaling and trigger

UE

RRC: Measurement Report (Event 1F)

RRC: Physical Channel Reconfiguration

RRC: Physical Channel Reconfiguration Complete

BTS RNC

UE put into compressed mode

RRC: Measurement Control

RRC: Measurement Report

RxLev measurements

RRC: Measurement Control

RRC: Measurement Report

BSIC verification

MSC

RANAP Relocation required

RANAP Relocation command

RRC: HO from UTRAN Command

ISHO execution

NBAP: RL reconfig. prepare

NBAP: RL reconfig. ready

NBAP: RL reconfig. commit

NBAP: CM command

NBAP: CM command

RANAP Iu release request

71

For internal use


Top N cells

Too low success

rate

No action

needed

No

Missing ADJG or

Bad Neighbor

planning ?

Wrong 2G Ncell

Parameter (BSIC)

Or BSIC collision

No

Yes

Yes

No

Too low ISHO triggering

threshold or

Too strict ADJG

minimum threshold

Non-optimum

Compressed mode

parameter set

Low ISHO

Success ?

Low ISHO

Measurement

success ?

Missing or wrong 2G

parameter in 2G MSC

or SGSN (BCCH, LAC,

CellID)

2G Ncell

Congestion Half Rate in 2G

Ncell ?

Poor GSM

Coverage

CM Start

Not

Possible?

Yes

Check admission

control rejection

TCP and RTWP

Yes

No

ISHO analysis Flow chart

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For internal use


ISHO analysis ISHO cause example (with OSS data)

Blue = RSCP triggered

Red = Ec/Io triggered

Black = DL RL power triggered

UE power triggered = 0

UL SIR target triggered = 0

HHO mostly triggered by event 1F

Event 1F again mostly due to low coverage, but not quality

73

For internal use


ISHO analysis ISHO cause example RSCP under 1F conditions (possible with MEGAMON)

Usually very low coverage under event 1F conditions

Consistent with counter statistics

74

For internal use


ISHO analysis ISHO cause example Ec/Io under 1F conditions

Usually acceptable Ec/Io even under event 1F conditions

Consistent with counter statistics

75

For internal use


ISHO - analysis ISHO failure example no target cell found (with OSS data)

100% target cell found

Each point represents one cell

80% target cell found

76

For internal use


ISHO - analysis ISHO failure example no target cell found

In several source cells often failure to find target cell

77

For internal use


ISHO - analysis ISHO failure example target cell not accessed

Much less critical to access target cell

78

For internal use


_ATTER_SYS_HHOHO_ADJ_INT

_COMPLER_SYS_HHOHO_ADJ_INT G_RNCss_per_ADJISHO_succe

ISHO per adjacency Concept and counters

ISHO attempts per adjacency

No attempts to distant cell might be removed from neighbor list

No attempts to nearby cell check whether BCCH frequency and BSIC is declared correctly in RNC data base

ISHO success per adjacency

High failure rate (several 10%) besides air interface performance check for BCCH-BSIC clash

100% failure rate check for inconsistency between RNC, BSC and core network data bases (e.g. CI, LAC and RAC declarations)

Attempt and success per adjacency monitored by AutoDef SHO

counters (M1015)

79

For internal use


CN

RNC RNC

Iu Iu

Iur

CN

RNC RNC

Iu Iu

Iur

CN

D-RNC S-RNC

Iu Iu

Iur

CN

RNC RNC

Iu Iu

Iur

SRNS relocation

SRNC anchoring

SRNC Anchoring not as such standardised mobility method

Can lead to limited mobility at the border between RNCs of different vendors

But can be implemented by applying undefined set of standardised features

SRNS Relocation standardised mobility method

3GPP options to use MM

Anchoring supported in Nokia SRNC only for CS RT and PS NRT services within

Cell_DCH

Keep Iur resources until release of the

call

Inter-RNC mobility Relocation and anchoring

Release Iur resources after drop of last source RNC cell

80

For internal use


Inter-RNC mobility

Relocation procedure and failure detected differently between source and target RNC

Target RNC

Target RNC sees relocation as incoming RRC connection setup with cause SRNC relocation

Setup, access and active counters incremented both for RRC and RAB

In case of failures, corresponding setup and access failure counters are incremented both for RRC and RAB (failure due to RNC)

Source RNC

Source RNC starts relocation procedure and releases finally RRC connection with cause SRNC relocation

Active release counters incremented both for RRC and RAB

In case of failures, corresponding active failure counters are incremented both for RRC and RAB (drop due to RNC)

Incoming and outgoing relocation

81

For internal use


RNC Source

RANAP Relocation required

Core RNC Target

RRC UTRAN mobility info

UE

Signaling and trigger

RNSAP Relocation commit

Inter-RNC mobility successful relocation

RANAP Relocation request

RANAP Relocation request ACK

SETUP PHASE

RRC setup attempt

RRC setup failure due to RNC

ACCESS PHASE

RRC setup complete

RRC access failure due to radio or RNC

RANAP Relocation command

RANAP Relocation detect

RRC UTRAN mobility info confirm

RANAP Relocation complete

RANAP Iu release

RANAP Iu release complete

ACTIVE PHASE

RRC release due to relocation

82

For internal use


Inter-RNC mobility possible failures

Target RNC does not respond to RANAP relocation request or RNSAP relocation

commit (internal RNC or Iu problem)

Target RNC responds with RANAP relocation request NACK (no resource available

in target RAN)

Synchronization failure on Iur (transmission problem)

UE does not respond to RRC UTRAN mobility info (air interface or UE problem)

Synchronization failure on radio link (air interface problem)

83

For internal use







HSPA setup

HSPA drop


84

For internal use


HSDPA setup successful session establishment Signaling and trigger

UE BS RNC

Capacity request

RL rec. prepare

RL rec. ready

AAL2 sig. ERQ

Radio Bearer Reconfig.

Radio Bearer Reconfig. Complete

AAL2 sig. ECF

RL rec. commit

session SETUP PHASE

session ACCESS PHASE

AAL2 sig. ERQ

AAL2 sig. ECF

HS-DSCH capacity request

HS-DSCH capacity allocation

After RRC establishment two further AAL links are needed for HSDPA

85

For internal use


Top N cells Setup Fail

BTS

High setup

failure rate

Setup Fail UL

return

Channel

Setup Fail Iub

Transport Setup Fail UE

Setup Fail

RNC internal

Setup Fail Too

Many Users

No action

needed

Check CE

resource usage

at BH

UL power

congestion

?

Check AAL2

Iub resource

congestion

Check RB

reconfiguration

Failure rate

Check RNC

Unit load

(DMPG) and

faulty alarms

Check number of

simultaneous

HSDPA users

No

Yes

Yes Yes Yes Yes Yes Yes

No No No No

No

HSDPA setup analysis process Flow chart

Lack of CE mainly problem for UL return DCH

For HSDPA CE reserved per scheduler

For associated DCH on DL just 1 CE per user

No

86

For internal use



HSDPA setup analysis process

Many HSDPA setup failure causes due to UE, Iub and UE

87

For internal use



1. Identify main failure contributor

2. If too many HSDPA users

Use license for more users

Use dedicated instead of shared scheduler

3. If due to UL DCH

Monitor UL load

Check PrxTarget and PrxNoise settings

Check for intermodulation

4. If due to UE

Check RB reconfiguration failure rate

Check air interface performance

Check ICSU log for UE type troubleshooting

88

For internal use



5. If due to BTS

Lack of UL channel resources

Check for SHO overhead (all branches must have enough CE capacity if UE is in SHO when HS-DSCH shall be allocated)

6. If due to Iub transport

Evaluate number of reconfiguration failure due the transmission

Check for SHO overhead (all inter-BTS branches must have enough capacity for associated DCH)

Check for number of individual AAL connections

Check for frame delay or even frame loss due to congestion

89

For internal use


With RU20 HSPA transport channels can be allocated directly to users in

Cell_FACH or Cell_DCH, without waiting for capacity request

UE must support HSDPA and HSUPA transport channels

HSDPA and HSUPA must be enabled in cell

Direct resource allocation always used when F-DPCH allocated to UE

Prior to RU20 for NRT user allocation of DCH 0/0 by AC

After receiving capacity request, RNC selects channel type

If no capacity request received by RNC, UE moved to Cell FACH

Direct resource allocation

HSDPA setup optimization

90

For internal use







HSPA setup

HSPA drop


91

For internal use


Top N cells

Pre-emption

High drop

ratio

Transition to

DCH due to

mobility

Transition to DCH

due to other

reason (e.g. type

of RAB)

Drop due to

radio

No action

needed

Normal Release

(No action

needed)

Normal Release

(No action

needed)

Normal Release

(No action

needed)

High SCC Failure

Rate

No

Yes

Yes Yes Yes Yes

No No No

Check CQI distribution

and Ec/Io distribution for

coverage issue

Check HSDPA mobility

settings (SHO and SCC

parameter)

No

Drop due to

other reason

No

Check RB reconfiguration failure

rate (UE response with failure or

no response at all)

Check ICSU log (UE type)

Yes

HSDPA drop analysis process Flow chart

Yes

HSDPA drop = soft drop

RNC tries to shift UE to Cell_FACH

RNC tries to keep RAB running

92

For internal use



HSDPA drop analysis process

Majority of DCH drops due to radio

93

For internal use







HSPA setup

HSPA drop


94

For internal use


UE

RRC: Measurement Report (e.g. Ec/Io)

NBAP: Radio Link Reconfiguration Prepare

BTS Source

BTS Target

RRC: Radio Bearer Reconfiguration

RNC

RRC: Radio Bearer Reconfiguration Complete

Serving Cell Change SCC successful procedure Signaling and trigger for inter BTS SCC

NBAP: Radio Link Reconfiguration Ready



ALCAP: Establish Request

ALCAP: Establish Confirm

NBAP: Radio Link Reconfiguration Commit


95

For internal use


UE

RRC: Measurement Report (e.g. Ec/Io)


BTS Source

RRC: Radio Bearer Reconfiguration

RNC

RRC: Radio Bearer Reconfiguration Complete

SCC successful procedure Signaling and trigger for intra-BTS SCC


ALCAP: Establish Request

ALCAP: Establish Confirm


Setup of transport resources only needed in case of inter-

WAM mobility

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For internal use


Addition

window

4dB

CPICH 1 R99

CPICH 2 R5/6

EC/I0

time SHO for A-

DCH initiated

Periodic

reports

Serving cell change

initiated

periodic reports as

long UE in SHO area

HSDPAServCellWindow RNC, 0..6, 0.5, 2 dB

Addition Time

Drop

window

6dB

SCC window settings SCC with associated DCH

CPICH 2 active CPICH 1 not

active anymore

97

For internal use


Addition

window

CPICH 1

CPICH 2

EC/I0

time Just periodic

reports

Serving cell change AND

active set update initiated

periodic reports as

long UE in SHO area Addition Time

HSDPASRBWindow RNC, 0..6, 0.5, 1 dB

HSDPAServCellWindow RNC, 0..6, 0.5, 2 dB

SCC window settings SCC with F-DPCH

CPICH 2 NOT

active yet

CPICH 2 active

together with SCC

Modified (smaller) SCC

window used, as no SHO

with event 1A yet

98

For internal use


Top N cells

SCC Fail BTS

High SCC failure

rate

SCC Fail AC SCC Fail

Transmission SCC Fail UE

SCC Fail

Others

No action

needed

Check BTS HW

Channelization

code

congestion ?

DL power

congestion

?

Check AAL2

Iub resource

congestion

Check RB

reconfiguration

Failure rate

Check RNC

internal transport

resources (DMPG)

ICSU

troubleshooting

No

Yes

Yes Yes Yes Yes Yes

No No No No

No

SCC Fail

Prevention

timer

Check

HSDPACellChange

MinInterval

parameter

Check

Maximum

number of

HSDPA users

No

No

Yes

SCC analysis process Flow chart

99

For internal use


HSPA started

SCC analysis process Failure cause example

Many serving cell change failure causes due to AC

100

For internal use


SCC analysis process

1. Determine main failure cause contributor

2. Check HSDPA setup performance of target cells if SCC failure rate of source cell is high

3. If high SCC failure rate due to admission control

In case of power congestion check HSDPA power settings (in case of dynamic power R99 should not throw out HSDPA completely)

Otherwise check number of HSDPA users

4. If high SCC failure rate due to BTS

Usually NOT lack of CE (associated DCH already in SHO before SCC, for HSDPA CE reserved per scheduler)

Check radio link reconfiguration failure causes of target cells

Check BTS hardware

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For internal use


SCC analysis process

5. If high SCC failure rate due to UE

Check RB reconfiguration failure rate

Check air interface performance

Check ICSU log for UE type monitoring

6. If high SCC failure rate due to transport

Evaluate number of reconfiguration failure due the transmission

Check for number of individual AAL connections

Check for frame delay or even frame loss due to congestion

7. If high SCC failure due to other reason

Check RNC internal transport resources usage (DMPG)

Requires ICSU troubleshooting

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For internal use


RNC

RNC

A

B

C

AS={A,B,C}

Normal SHO for A-DCH

AS={A,B,C}

C= best cell, HS-DSCH data over Iur

AS={C}

Trigger relocation

SCC User data over Iur Previous releases up to RU10

Inter-RNC HS-DSCH serving cell change and relocation at the same time

No flow of user data over Iur

Switch back to DCH not required, but nevertheless interruption of HSDPA service by the mobility procedures

Since RU20

First inter-RNC serving cell change, then relocation

Flow of user data over Iur, when inter-RNC neighbor becomes new serving cell

HSDPA service not interrupted by the mobility procedures

02 RN31572EN40GLA0 Performance Monitoring

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Transcript of 02 RN31572EN40GLA0 Performance Monitoring