94516831 3G KPI Analysis Report

WCDMA : KPI ANALYSIS & OPTIMIZATION Network planning& Optimization

Illustration on RAN KPI-RU20 SRNC Relocation

RNC Accessibility: RRC Setup & Access Rate RAB Setup & Access Rate Call Setup Success Rate PS setup success rate (NRT,HSDPA, HSUPA)

SRNC

UE

BTS1

X

Retainability: RRC Drop Rate RAB Drop Rate PS success rate (NRT, HSDPA, HSUPA)

RNC Usage: Cell Availability Ave. Uplink Load Ave. Downlink Load HSDPA Throughput Cell Throughput

Mobility: SHO/ISHO Success Rate SHO Overhead HDSPA/HSUPA SCC success Presentation / Author rate / Date

BTS2

X

Preemption

Genuine Call Setup Failure Scenarios – RF issue

• Interference / Dominance / Coverage • Missing neighbour

– System Issue - BTS

• No response to “RRC Connection Request” • “RRC Connection Reject” to “RRC Connection Request” – System issue - RNC

• “CC Disconnect” after “Call Proceeding” due to “DL RRC Connection Release” – Core NW

• “CM Service Abort” after “CM Service Request” – System issue (test number)

• “CC Disconnect” after “CC Progress”

Genuine Drop Call scenarios RF issue – Interference / Dominance / Coverage

– Missing Neighbours

System issue BTS – Sudden “CC Disconnect” due to “DL RRC Connection Release” – Sudden drop to idle, no disconnect messaging

System issue RNC – Sudden “CC Disconnect” due to “DL RRC Connection Release”

KPI Definitions

The KPIs to be monitored from the RAN could be: – Cell availability – Call Setup Success Rate (CSSR) – Call Drop rate – SHO/ISHO/HSPA SCC success rate – Packet Session setup/success rate (NRT, HSDPA, HSUPA) In NOLS: – RNC counter description – NetAct DB description for RNC measurements – WCDMA RAN Key Performance Indicators – Key Indicator Changes – Measurement Changes

Presentation / Author / Date

AMR CS Call Phases UE

WBTS

DRNC

1. Cell search, BCCH decoding & RACH access 2. RRC connection set-up 3. UE <--> CS-CN signalling 4. RAB set-up 5. UE <--> CS-CN Signalling 6. Service Established 7. Branch addition/deletion & Active set update 8. Service Released

SRNC

CN

Call Setup Failure Analysis Process__DT

Start

A

Best server’s RSCP > -102dBm

Missing Neighbour ?

Yes Best server’s Ec/No > -12dB

Coverage Optimization

No

No

Yes

No

Dominance Optimization

Neighbour list Optimization

Yes

B

UL coverage & RACH parameter. Optimization (changing serving cell)

No

AICH(ACK) received?

Report & Finish (Check failure cause) No

Yes “RRC Connection Setup” received?

No

Yes

D

Report & Finish (Reason of problem: L1 sync fail)

No

No

AC optimization (check PrxNoise & interferer around BTS)

(DCH) “RRC Connection setup Completed” sent from UE?

“Radio Bearer setup failure”Received? Ye s

C

Yes

Report & Finish

Yes Report & Finish (Check failure cause)

“RRC Setup Reject” received?

E

Report & Finish Check failure cause (Not radio problem/cell update)

Call setup failures – MissingA Neighbour Missing neighbour analysis over the whole route (3G-3G, 3G-2G) Search for failures due to missing 3G3G neighbours Search for failures due to missing 3G – 2G neighbours – It is suggested to place 2G scanner to the test vehicle

Call Setup Failure Analysis-B Block B The purpose of this activity is to check the Random Access Process is working adequately by investigating whether AI (Acquisition Indicator) has been received through DL AICH If AICH was not received by UE, the cause of the problem can be classified into: – Inadequate RAN parameter related to Random Access: RAN parameter

Call Setup Failure Analysis-B RNC WBTSB UE Block Preamble/RACH

Acquisition Indicator/AICH RRC: RRC Connection Request/PRACH NBAP: RADIO LINK SETUP REQUEST NBAP: RADIO LINK SETUP RESPONSE

RRC: RRC CONNECTION SETUP/FACH L1 Synchronisation NBAP: SYNCHRONISATION INDICATOR

RRC: RRC CONNECTION SETUP COMPLETE/DCH UE in CELL_DCH state

B

RACH Process Downlink BS

L1 ACK / AICH Not detected UEtxPowerMaxPRACH

PowerRampStepPRACHpreamble

…… Uplink MS

…… Message part

Preamble Preamble 1 2

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

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

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

Call Setup Failure Analysis-B Block BNo Solutions for RACH optimisation To Max UE Tx power hit Toincrease increasePRACH_Preamble_retrans PRACH_Preamble_retrans Or OrPowerRampStepPRACHPreamble PowerRampStepPRACHPreamble

the UE_P_MAX(24dBm)?

Yes Yes Is UL Interference abnormally HIGH?

Report Reportthere theremight mightbe bean aninterfering interfering source Nearby the serving source Nearby the servingcell cell

No Change Changethe theServing Servingcell cellto tocover coverthe theproblem problemArea Area => UE is too far to reach the serving cell => UE is too far to reach the serving cell

Call Setup Failure Analysis-B Block B Open loop Power Control parameters from RACH Info message

Call setup failures – SystemC No response to “RRC Connection Request” issue BTS – Good RF conditions – Wrong MHA settings or cable loss settings can cause the site not to “hear” the UE – PrxNoise statistics, receive link parameters and HW units to be checked (faulty MHA, wrong MHA parameters, wrong cable / feeder loss parameters, faulty units)

Call setup failures – SystemC issue BTS “RRC Connection Reject” after “RRC Connection Request” – Good RF conditions – Admission Control can reject too many (or admit too many) connection requests due to wrong PrxNoise measurements. – PrxNoise statistics, receive link parameters and HW units to be checked

C Call Setup Failure Analysis UE has the appropriate DL/UL coverage but if RNC does not allow to set up the RRC connection of the requested RAB (Radio Access Bearer), Call setup will fail. Admission Control (AC) is involved in RRC connection setup. AC can reject RRC reject RRC connection Setup due the DL Load, UL load or DL Spreading codes

– Marginal Load Area: • If measured UL (PrxTotal) or DL (PtxTotal) load exceeds target thresholds (PrxTarget and PtxTarget) AC can still admit new RAB to the cell if a new non-controllable load keeps below target thresholds (in practice this means that AC can admit only new controllable load RABs i.e. NRT RABs)

– Overload Area: • If measured UL (PrxTotal) or DL (PtxTotal) load exceeds

C Call Setup Failure Analysis

• During the pre-optimization phase it is unlikely that AC will stop an RRC connection setup during the drive testing because there are normally very few UEs in the network. (Traffic loading is trivial) • However, it should be checked that measured PtxTotal and PrxTotal are less than PtxTarget (e.g. 40dBm) and PrxTarget (e.g. 4dB, 60% loading) respectively. • If DL AC does not allow RRC setup check the Tx power of WBTS, # of channels transmitted, Signaling messages. • If UL AC does not allow RRC setup: Check out if there is an interfering source nearby the serving cell.

D Call Setup Failure Analysis To check if Layer 1 Synchronization (slot/frame sync) has failed If “RRC Connection Setup” was received by UE but UE does not send “RRC Connection Setup Completed”, we will report “L1 synchronization failure” and have to check L1 system messages.

Call setup failures – SystemE issue RNC • “CC Disconnect” after “Call Proceeding” • Good RF conditions • Failures in RAB setup occur between the “RAB Assignment Request” being received from Core Network and the RAN sending out Radio Bearer Setup. Therefore the failure is between BTS and Core Network.

•

Call setup failures – SystemE issue RNC “CC Disconnect” after “Call Proceeding” (cont.)

•

An example (site shows high values on counter “RAB_STP_FAIL_CS _VOICE_BTS” during the drive test

•

In the recent check the counter showed no failures.

Call setup failures – Core “CM Service Abort” after NW “CM Service Request” Good RF conditions “Security Mode Command”-message not received by UE, thus the failure is believed to be at Core Network.

UE

Node B

E

MGW

RNC

RR C Connection E stablishment Initial Direct Transfer (CM Service Request)

SC CP : Connection R equest S CCP : Connection Confirm Location Reporting Control Common ID S ecurity Mode Command

• R R C: Initial Direct Transfer message is sent using acknowledged mode R LC to the CS core domain. Routing is to be based upon the local -TMSI P

• The NAS message is not read by the RNC but is forwarded to ultimedia the m gateway. The NAS message includes the IMSI as a UE identity

• The SCCP : Connection R equest message establishes the connection orientated signallingnlink i

the same way as it was for the R RC connection phase.This does t reserve no any resources for the AMR call itself.

• The Connection Confirmmessage identifies the RNC with a destination local reference hichwis the same as the source reference within the Connection Requestmessage

• The Connection Confirmmessage identifies the CS core with a source local reference • The CS core sends aRANAP: Location Reporting Control message to the RNC requesting information regarding the location of a particular UE

• The RANAP: Common IDmessage specifies the IMSI belonging to the UE • The Security Mode Command message triggers the start or stop of ciphering and integrity protection.

Call setup failures – SystemE “CC Disconnect” after “CC (test number) Issue Progress” Cause: recovery on timer expiry The call goes via IN SCP to a recording. A static test was done by Nokia Customer Care and in few instances the call dropped after 30 seconds of recording passed. Hence the problem is associated with the test number not the RAN

30 sec

Cause: recovery on timer expiry

State Transition triggers

Phys. Reconfiguration

After RT call with inactive PS RABs

Frequent cell updates

Phys. Reconfiguration

UTRA RRC Connected Mode

URA Update, UL data, Paging

Fast call setup from CELL_PCH

CELL_PCH

URA_PCH

Fast call setup from URA_PCH

Phys. Reconfiguration UL/DL activation timer

After RT call with inactive PS RABs & high mobility in CELL_DCH

CELL_FACH

CELL_DCH

Phys. Reconfiguration Cell Update, UL data, paging

RB. Reconfiguration Traffic Volume, RACH load RRC Setup / Release

RB. Reconfiguration Inactivity Timer, Overload IDLE Mode

State Transition triggers IDLE

Call Setup 1.2 sec

DCH Transition DCH-FACH due to inactivity  10 sec )Parameter) FACH PCH

Transition FACH-PCH du to inactivity  2 sec )Parameter)

FACH DCH

IDLE

Wake up time PCH – DC due to activity  3 sec

CELL_DCH State

• DCCH and – if configured – DTCH • Dedicate physical channel in use • UE location known on active set cell level • UE responsible for measurement reporting • Cell system information on BCCH • RRC messages on DCCH active set cell

25

© 2006 Nokia Layer 3 (RRC) / Kittipong Thamapa

active set cell

CELL_FACH State • DCCH and – if configured – DTCH • FACH used for higher layer data transfer, • UE monitors FACH permanently • Uplink transmission on RACH • UE location known on serving cell level • UE performs cell re-selection • UE responsible for measurement reporting • Cell system information on BCCH • RRC messages on BCCH, CCCH and DCCH

26


serving cell

CELL_PCH• no and URA_PCH State DCCH and DTCH

• Before uplink transmission ⇒ UE moves to CELL_FACH • UE must be paged • RRC messages on BCCH and PCCH • In CELL_PCH - UE location known on cell level - UE performs cell re-selection and cell updates • In URA_PCH - UE location known on URA level - UE performs cell re-selection and URA updates •one or several cells URA – UTRAN Registration Area •independent from LA URA 1 RNC supply area URA 2 27


URA 3

RU20 New Counters & Measurements

/

Cell Availability RNC_183c Cell Availability KPI counts Cell availability from user point of view: Cell _ Availability =

100 * sum( AVAIL _ WCELL _ IN _ WO _ STATE ) sum( AVAIL _ WCELL _ EXIST _ IN _ RNW _ DB )

M1000C178 AVAILABILITY WCELL IN WORKING STATE • # of samples when WCELL is in WO State. Counter M1000C180 is always updated along with this counter • Counter is updated with the value 1 once in approx. 5 seconds when the WCELL is in WO State M1000C180 AVAILABILITY WCELL EXIST IN RNW DATABASE • # of samples when WCELL is configured in the database. This counter is used as a denominator for cell availability calculation • Counter is updated with the value 1 one in approx. 5 seconds when the WCELL is configured in the radio network database


Cell Availability – There is also Optional Cell availability KPI, which counts Cell Availability from network point of view. Situation where WCELL is blocked by User are excluded from the formula. – RNC_727a Cell Availability blocked 100KPI, * sum(excluding AVAIL _ WCELL _ IN _ WO _by STATE ) Cell _ Availabili ty _ excluding _ BLU _ state = user state (BLU), Counts Cell availability from network _ WCELL _ EXIST _ IN _ RNW _ DB   AVAIL   sum point of view: − AVAIL _ WCELL _ BLOCKED _ BY _ USER   M1000C179 AVAILABILITY WCELL BLOCKED BY USER • # of samples when WCELL is BLU State. Counter M1000C180 is always updated along with this counter • Counter is updated with the value 1 once in approx. 5 seconds when the WCELL is in BLU state


CSSR definition

DNO Optimization Processes / JC Ejarque

Low in CSSR? Call phases Setup Phases Identify call setup failure

CSSR affected if any of the followings take place. 1. RRC Conn. Setup Fail 2. RRC Conn. Access Fail 3. RAB Setup Fail 4. RAB Setup Access Fail

Call Setup Success

Call Drop

Connected

Call Setup Phase RRC RRC RRC RRC Conn. Req Conn. Setup Conn. Acc Conn. Act

RAB Setup


RAB Drop

Low in CSSR? RRC/RAB Setup & Access Analysis Process Flow Chart

Top (N) RAB Setup and Access failures

Top (N) RRC Setup and Access failures

Cell and Neighbour Cells availability Alarms/Tickets

Setup Failure Cause?

Sites OK ?

RNC Yes Setup /Access

setup

Setup /Access

Troubleshooting

BTS/TRANS/FROZBS AC

setup

UL/DL Interference (DL codes)

Access

Capacity Optimisation Access

Yes 3G cell at inter-RNC border ?

SRNS Relocation troubleshooting

NO Interference Coverage/Interf erence

RF Optimisation Coverage


Call Setup Success Rate (CSSR) Poor CSSR could be a result of

– Poor coverage or dominance or interference issues in Radio interface – Capacity issues in Radio or Iub interface – Configuration issues in WBTS (parameters or HW) CSSR is essentially RRC Setup Success * RAB Setup Success (or successful PS session setups in case of PS call) CSSR covers all the steps from the initial RRC connection request from the UE to the network, through the RRC setup phase and the RAB setup phase, and until user data is starting to get transferred. The CSSR formulas are for different traffic classes like: – CS voice calls (RNC 565 f) – CS video calls (RNC 566e) – PS RT Streaming Calls (RNC 575 d) – PS NRT Calls (Interactive & Background) (RNC 576d) Presentation / Author / Date

UE

Definition of Call Set-Up Success Rate (CSSR)

RRC: Connection Request

RNC

BTS

CN

RRC Connection Setup phase

Resource Reservation in RNC, BTS, Transmission

RRC: RRC Connection Request Setup RRC Connection Access phase RNC waits reply from UE

RRC: RRC Connection Completed RRC: Initial Direct Transfer cm service request DIRECT TRANSFER (Call Proceeding)

RANAP: Initial UE Message

RAB Connection Setup phase

RANAP: RAB Assignment Request

Resource Reservation in RNC, BTS, Transmission

RRC: Radio Bearer Setup

RAB Connection Access phase RNC waits reply from UE

RRC: Radio Bearer Setup Complete DIRECT TRANSFER (Alerting) DIRECT TRANSFER (Connect) DIRECT TRANSFER (Connect Acknowledge) Presentation / Author / Date

RANAP: RAB Assignment Response

Call Setup Success Rate Call Setup Time

UE

RRC Connection Setup & Access and Active RNC

BTS

CN

RRC: RRC connection Request RRC SETUP phase RRC Setup time

(Resource Reservation in RNC, BTS, Transport) RRC: RRC connection Setup RRC ACCESS phase (RNC waits for Reply from UE) RRC: RRC connection Setup Complete RRC ACTIVE phase RRC: Initial Direct Transfer RANAP: Initial UE Message UE-CN Signalling (E.g. RAB Establishment and Release)

RRC SETUP fails if some of the needed resources (RNC, BTS, AIR, Transport) are not available. When an RRC setup failure occurs the RNC sends an RRC: RRC CONNECTION REJECT message to UE RRC ACCESS fails if the UE does not reply to RRC: RRC CONNECTION SETUP message with the RRC: RRC CONNECTION SETUP COMPLETE message in given time, if the BTS reports a radio link synchronisation failure or in an RNC internal failure occurs 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 RRC send a RANAP: IU RELEASE REQUEST to all involved CNs and waits for RANAP: IU RELEASE COMMAND message (s)

RANAP: Iu Release Command RRC: RRC connection Release RRC: RRC connection Release Complete Release RRC resources in RNC, BTS, Transport

RRC ACTIVE release cause can be either ISHO, IFHO, SRSN relocation or preemption Presentation / Author / Date

RAB Setup & Access and Active

RAB Access failures are not so Common

UE

RNC

BTS

CN

RAB SETUP fails if some of the needed resources (RNC, BTS, AIR, Transport) are not available. When an RAB setup failure occurs the RNC sends a RANAP: RAB ASSINGMENT RESPONSE message to the CN with an appropriate failure cause

RRC Connection Active Phase, UE-CN Signalling RANAP: RAB Assignment Request RAB SETUP phase RAB Setup time

(Resource Reservation in RNC, BTS, Transport) RRC: Radio Bearer Setup RAB ACCESS phase (RNC waits for Reply from UE) RRC: RB Setup Complete RANAP: RAB Assignment Response

RAB ACTIVE phase

RAB ACCESS fails if the UE replies with an RRC: RADIO BEARER SETUP FAILURE message or the connection cannot be established in a give time. When a RAB access failure occurs, the RNC sends a RANAP: RAB ASSINGMENT RESPONSE message to the CN with an appropriate failure cause. Immediately after this, the RNC sends also a RANAP: IU RELEASE REQUEST to the CN and waits for RANAP: IU RELEASE COMMAND message

(User Plane Data Transfer) RAB Holding Time

RANAP: RAB Assignment Request with IE: RAB reconfiguration RAB Reconfiguration Actions (Reconfigure RAB resources in RNC, BTS, Transport) RRC: RB Reconfiguration RRC: RB Reconfiguration Complete RANAP: RAB Assignment Response RANAP: RAB Assignment Request with IE: RAB Release RRC: Radio Bearer Release RRC: Radio Bearer Release Complete RANAP: RAB Assignment Response Release RAB resources in RNC, BTS, Transmission

RAB ACTIVE fails when an interface related (Iu, Iur, Iub, or Radio) or RNC internal failure occurs, and the failure causes the release of the RAB connection. • If the UE has more than one RAB connection and the failure is not so critical that it would lease to an RRC Connection drop, only the failed RAB connection is released. The RNC sends a RANAP: RAB RELEASE REQUEST message to the CN and waits for a RANAP: RAB RELEASE COMMAND or RANAP: IU RELASE COMMAND from CN • Otherwise, both the RRC connection and RAB connection (s) are released. The RNC send a RANAP: IU RELASE REQUEST message to the CN and waits for a RANAP: IU RELEASE COMMAND MESSAGE from the CN


RRC connection set up failure

o processing power on ICSU unit RRC Connection is rejected ICSU can not process the call

coming call request can not be handled due to lack of ICSU processing No hand free” is RNC internal clear code.

UE

BS RRC Connection Request

RNC ICSU overload

RRC Connection Reject Cause: congestion

Failure Counter M1001C618

Call Setup Failures RRC and RAB phases Phase:

Setup

Active

Access Complete

Active Release

Attempts

Active Failures

Success

Active Complete Access

Setup Complete

Access

RRC Drop

Access failures Setup failures (blocking) Presentation / Author / Date

RRC connection setup RAN resources are 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 is dropped. RAB setup Attempts to start the call RAB setup access RAB active phase UE has RAB connection CSSR affected if any of the followings take place. • RRC Conn. Setup Fail • RRC Conn. Access Fail • RAB Setup Fail • RAB Setup Access Fail

Call setup Success rate -CSSR

/

Call Setup Success Rate (CSSR) CSSR KPI for CS voice from end user perspective (RNC 565f) 100 * ( sum( MOC _ CONV _ CALL _ ATTS − MOC _ CONV _ CALL _ FAILS + MTC _ CONV _ CALL _ ATTS − MTC _ CONV _ CALL _ FAILS + EMERGENCY _ CALL _ ATTS − EMERGENCY _ CALL _ FAILS − RRC _ ACC _ REL _ EMERGENCY − RRC _ ACC _ REL _ MO _ CONV − RRC _ ACC _ REL _ MT _ CONV ) AMR _ CSSR = sum( MOC _ CONV _ CALL _ ATTS + MTC _ CONV _ CALL _ ATTS + EMERGENCY _ CALL _ ATTS − RRC _ ATT _ REP _ MO _ CONV

RRC part

− RRC _ ATT _ REP _ MT _ CONV − RRC _ ATT _ REP _ EMERGENCY − RRC _ ACC _ REL _ EMERGENCY − RRC _ ACC _ REL _ MO _ CONV − RRC _ ACC _ REL _ MT _ CONV − RRC _ CONN _ STP _ REJ _ EMERG _ CALL )

*

( sum( RAB _ ACC _ COMP _ CS _ VOICE ) sum( RAB _ STP _ ATT _ CS _ VOICE ))

RAB part

RRC request repetitions done by UE after RRC reject are excluded from denominator (not necessarily seen as failures from the user's perspective) – Emergency calls re-directed to GSM layer are excluded from denominator The occurred cell re-selectionsPresentation are subtracted / Author / Date both from the numerator and denominator because they are not considered as call attempts

_PACKET CALL SETUP SUCCESS RATE


PS Call Setup Success Rate (CSSR) RNC_576d- Packet Call Setup Success Ratio [%] over the reporting period. Includes both Interactive and Background PS calls 100 * ( sum( MOC _ INTER _ CALL _ ATTS − MOC _ INTER _ CALL _ FAILS + MOC _ BACKG _ CALL _ ATTS − MOC _ BACKG _ CALL _ FAILS + MTC _ INTER _ CALL _ ATTS − MTC _ INTER _ CALL _ FAILS + MTC _ BACKG _ CALL _ ATTS − MTC _ BACKG _ CALL _ FAILS + EMERGENCY _ CALL _ ATTS − EMERGENCY _ CALL _ FAILS − RRC _ ACC _ REL _ INTER − RRC _ ACC _ REL _ MO _ BACKG ( sum( RAB _ ACC _ COMP _ PS _ INTER − RRC _ ACC _ REL _ MO _ INTER − RRC _ ACC _ REL _ MT _ BACKG ) + RAB _ ACC _ COMP _ PS _ BACKG ) PS _ CSSR = * sum( MOC _ INTER _ CALL _ ATTS + MOC _ BACKG _ CALL _ ATTS sum( RAB _ STP _ ATT _ PS _ INTER

RRC part

MTC _ INTER _ CALL _ ATTS + MTC _ BACKG _ CALL _ ATTS − RRC _ ATT _ REP _ INTER − RRC _ ATT _ REP _ MO _ INTER − RRC _ ATT _ REP _ MO _ BACKG − RRC _ ATT _ REP _ MT _ BACKG − RRC _ ACC _ REL _ INTER − RRC _ ACC _ REL _ MO _ BACKG − RRC _ ACC _ REL _ MO _ INTER − RRC _ ACC _ REL _ MT _ BACKG ))

+ RAB _ STP _ ATT _ PS _ BACKG ))

RAB part

RRC request repetitions done by UE after RRC reject are included in the formula * The occurred cell re-selections are subtracted both from the numerator and denominator because they are not considered as call attempts from mobile enduser point of view. The UE has made/ Author a new RRC connection via another cell and Presentation / Date Attempts-counter is updated in the new cell for the new attempt.

Low in CSSR: Failure Counters RRC Conn Setup & Access Analysis

RRC_CONN_STP_FAIL_AC Check UL Interference, DL Power & Code occupancy if there is need to upgrade radio capacity RRC_CONN_STP_FAIL_BTS Evaluate NBAP counters (radio link reconf. Failures) and KPIs for troubleshooting BTS resources Check BTS configuration in terms of CE allocation – Use Channel Element (5001) Counters in order to evaluate lack of Channel Elements Expand the Capacity or decrease the traffic offered to the site until the problem is solved In case BTS is not responding delete and re-create COCO RRC_CONN_STP_FAIL_TRANS Evaluate Number of reconfiguration failure due the transmission Check COCO Configuration Expand the capacity or decrease the traffic offered to the site until the problem is solved RRC_CONN_STP_FAIL_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care department RRC_CONN_STP_FAIL_RNTI ALLO FAIL RNC decides to reject RRC connection request due to RNTI allocation failure caused by RRMU overload DNO Optimization Processes / JC Ejarque

Low in CSSR: Failure Counters RRC Conn Setup & Access Analysis RRC_CONN_STP_FAIL_IUB_AAL2_TRANS Updated when there is shortage or blocking of AAL2 resource A subset of RRC_CONN_FAIL_TRANS which include ERQ/ECF fail due to some reason such as DMPG problem in RNC + ERQ/ECF fail due to transport resource needed in RNC between RNC/MGW RRC_CONN_ACC_FAIL_RADIO Dominant failure causes due to wrong UL or DL coverage UL Coverage -> Check if cell is affected by an external interference (Thermal Noise measurements). DL Coverage -> Tune SCCPCH Power if UE does not receive the RRC Setup Message -> If UE does not synchronize, reduce N312 from 2 to 1 (depends on UE model) or tune CPICHToRefRABOffset vs. Qqualmin (or Qrxlevmin) RRC_CONN_ACC_FAIL_MS UL Coverage -> Tune Cell Dominance (or CPICH) in order to balance UL and DL (if UL interference if not the cause). Check if cell is affected by an external interference (Thermal Noise measurements).


Low in CSSR: Failure Counters RAB setup & Access Fail Root Cause Analysis: RT and NRT (I/B) domains

RAB_STP_FAIL_XXX_AC Check UL Interference, DL Power & Code occupancy if there is need to upgrade radio capacity using the already distributed Nokia Capacity Check BO report. Check PrxTarget / PrxOffset / of the affected cells RAB_STP_FAIL_XXX_BTS Evaluate NBAP counters (radio link reconf. Add failures) and KPIs for troubleshooting BTS resources Check BTS configuration in terms of CE allocation – Use Channel Element (5001) Counters in order to evaluate lack of Channel Elements Expand the Capacity or decrease the traffic offered to the site until the problem is solved. In case BTS is not responding delete and re-create COCO RAB_STP_FAIL_XXX_TRANS Evaluate Number of reconfiguration failure due the transmission Check M1005C128 CANC_ADD_SRNC_TRAN_STP_FAIL Check RAB_STP_FAIL_XXX_IUB_AAL2, M1001C531-C533 Check COCO Configuration RAB_STP_FAIL_XXX_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care department DNO Optimization Processes / JC Ejarque

Low in CSSR: Failure Counters RAB setup & Access Fail Root Cause Analysis: RT and NRT (I/B) domains RAB_ACC_FAIL_XXX_UE Evaluate Cell resource Prx and Ptx parameters (same as RAB_STP_FAIL_XXX_AC Case) RAB_ACC_FAIL_XXX_RNC Typically RNC fault or Incoming SRNC Relocation Failure (inter-RNC border) Required ICSU log tracing if no RNC fault or SRNC relocation problem Communicate the problem to Care department.


High in DCR? Top (N) drops

Cell and its Neighbour Cells availability Alarms/Tickets

Neighbours’ Performance (use SHO success per adjs counters to identify badly performing neighbours) & Map

Site OK ? YES

Audit adjacent sites for alarms, Availability, configuration and capacity

NO

Configuration & Parameter audit

Conf OK ? YES SHO Success Rate < 90%?

SHO

3G Cell at RNC border?

ISHO Failures

ISHO

Core: Inners / Outers audit

YES

No cell found ratio >40 %

Iur performance

Investigation Iur

New site ? Analyse last detailed radio measurements

NO

YES

To p iss ue s

YES

YES

NO

2G : TCH blocking 3G : Wrong N’ borgs definition

Traffic

RF and IF/IS HO neighbour optimisation

3G cell covers over a coverage hole ?

3G cell at inter-RNC border ?

RF and ISHO neighbour optimisation

YES

NO ISHO Success Rate < 95%

No cell found ratio > 90 % and enough ADJG


Coverage issue (new site needed)

Call drop analysis process Start

SHO Failure Analysis

Yes

SHO Failed No

ISHO Failure Analysis

Yes

ISHO Failed No No

Best server’s RSCP> -102dBm

No

Coverage Optimization No

Missing Neighbour Best server’s Ec/No> -12dB

B

Investigate possible BTS or RNC problem

A


Yes

Dominance Optimization Neighbour list Optimization

Call Drop Analysis process – SHO Analysis Start

Check Iur

Yes

Inter RNC HO

Check neighbor definition parameters No Fix SC Clash

Load Optimisation

Yes

C Yes

No

SC Clash No

Yes

Congestion on target cell

UE Tx Power Max

Yes

No

Check RF Levels

Yes

No DL Tx Power Max

DL ASU received

No

Uplink Interference

Yes

Load Optimisation/ External Interferer

D

No

Link Unbalanced No Presentation / Author / Date

Yes

CPICH Optimisation

Drop call failures – RF issue

RF drops mostly due to poor dominance or interference Poor coverage could lead to ISHO, although poor dominance or interference can cause ISHO to fail. Rapid field drop can cause drop due to coverage Poor dominance or interference can cause Compressed Mode (CM) to start even if RSCP is still good. In CM UE transmits with higher power (more interference) and spends less time on 3G (less accurate measurement reporting) Poor dominance or interference can lead to Active Set update failures and eventually to drop call.


Poor dominance causes Active Set update failures

A


DL synchronisation is lost -> UE has stopped transmitting TrChAgg and DL DPCCH BER high


A


A

Fairly good CPICH Pilot EcNo Transport Channel BER. Btw UE<->RNC (MAC layer)

Sometimes DPCCH BER (btw UE<>WBTS) can be a better indicator of what's happening to the dedicated channel than the CPICH EcNo, in particular in the case that power control may not be tracking well


Drop Call Failures – System B issue BTS Sudden drop to idle, no disconnect messaging – Site malfunctions to be checked – In the example below site had faulty unit (WTR)

Drop to IDLE


Drop Call Failures – System B DPCCH Issues RNC “CC Disconnect” due to BER “DL RRC Connection Release” No response to UL Measurement Reports In the example site had no alarms, good RF & BER Not able to add SC265 to Active Set, next call on the same cell => no failure. Difficult to troubleshoot if the failure does not happen systematically => follow up in the next weeks drive / do a separate drive test in the area

Sudden “RRC Connection Release” Presentation / Author / Date

Drop call failures (SC conflict) Transport Sudden drop to idle channel mode (no disconnect messaging) Cause of the failure: overshooting site and SC reuse Short term solution to add overshooting neighbour in ADJS definitions

BLER 100%

Cell ABC, SC258


C

Drop call failures – Uplink Interference UL interference from the SIB7 message


D

Drop call failures – Link UL & DL Power Control commands can help indicating problems in link Balance balance. PC frequency is 1500 Hz, thus ideally the sum of PC commands to increase or decrease power is 1500 E.g. if the sum of UL PC commands is < 1500, this would indicate UE is starting to loose synchronization in Compressed Mode there is less PC commands, UE spends time on 2G

D

UE RX power control message: DL reception weak -> UE is ordering WBTS to increase power.

Sum of UL PC commands < 1500, UE not receiving all the PC commands.


Drop call failures – System issue RNC or BTS ? “CC Disconnect” due to “DL RRC Connection Release” is just a consequence of failure which can be due to different reasons – From UE point of view L3-messaging does not identify the point of failure distinctly – BTS or RNC failure? => Suspect BTS first, then RNC Rule out BTS failures – Check the site performance from Counters (Iub, Service level, cell resources SHO, etc) and that site is carrying traffic – PrxNoise, receive link parameters, alarms – SC–reuse – UE performance ?

Identified causes for Active Set Update failure – “Deaf” sites (PrxNoise) – Faulty HW – SC-reuse Presentation / Author / Date

/

HSDPA low • Low HSDPA throughput root causes analysis process throughput? START OSS counters measurement data collection Identify Low throughput areas if exist

YES

YES

Low through put due to low Ec/No or CQI If low throughput due to low Ec/No or Poor CQI, identify reason • Bad Coverage Planning • Quality issue due the neighbour planning • HSDPA Parameters are correctly set up • Change Antenna tilt etc. Implement Changes

NO

If throughput is low in network level, the reason can be also FTP/HTTP server settings (fire wall), Measurement tools etc.

No Optimisation Required NO Identify reason for low throughput if not RF • Mobility (cell change too frequent) • No HSDPA coverage • Iub / Iu User Plane Capacity • Other HSDPA users in Business Object report already delivered in same WBTS/Cell order to measure all Start • DCHParameter traffic too High (DPA, related HSDPA Optimisation by tuning HSDPA Priority) throughput KPIs • HSPDA Mobility parameters (FMCS) • PtxMaxHSDPA (WCEL) • Dynamic Flow Control set to ON (WBTS)


RU10 Reporting Suite • RNC level system program added • Corrections to Capacity report • Modifications to Service level report (Streaming class added+ some other RNC_169e:DR + GAN HO corrections) added, but load & service based counters removed

Report Topic Name 1. System Program 1. System Program 2. Capacity 2. Capacity 2. Capacity 2. Capacity 3. Service Level 3. Service Level 3. Service Level 3. Service Level 4. Traffic 4. Traffic 4. Traffic 4. Traffic 4. Traffic 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover 5. Mobility and Handover

Report Name System Program RNC Level System Program Cell Level RNC Capacity Node B Capacity Cell Capacity NRT Radio Bearer Statistics Service/Session Accessibility Analysis Service/Session Retainability Analysis RAB Holding Times Service Summary Allocated Traffic Amounts (R99 + HSPA) Cell Data Volume and Throughput at RNC Traffic Summary Used CE Capacity per RB Type in RNC Utilization Shares of Total Traffic Allocation Amounts Active Set Size for NRT-RT Traffic HSPA Serving Cell Change IFHO Adjacencies Inter-System Handover per Cause Inter-System Handover Performance Inter-System Handover Reasons ISHO Adjacencies Load Based HO Related Resources Load Based IFHO/ISHO Performance Load Based IFHO/ISHO Triggering Service Based IFHO/ISHO Performance SHO Adjacencies Soft Handover Performance


Report ID RSRAN084 RSRAN000 RSRAN068 RSRAN066 RSRAN067 RSRAN013 RSRAN073 RSRAN079 RSRAN021 RSRAN003 RSRAN070 RSRAN077 RSRAN026 RSRAN022 RSRAN071 RSRAN078 RSRAN033 RSRAN044 RSRAN019 RSRAN023 RSRAN018 RSRAN045 RSRAN047 RSRAN048 RSRAN049 RSRAN050 RSRAN046 RSRAN028

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RU10 Reporting Suite

Modifications to KPIs due to streaming class + 64 HSDPA users/cell

Report Topic Name 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 8. Transport 7. HSPA 7. HSPA 7. HSPA 7. HSPA 7. HSPA 7. HSPA 7. HSPA 6. Signalling 6. Signalling

Report Name ATM Interface Traffic Load ATM VCC Traffic Load ATM VPC Traffic Load FTM Packet Transport Performance FTM Performance Iu-PS Throughputs Iub Throughputs Traffic on AAL5 Traffic on ATM Layer Traffic on Physical Medium Sub-Layer Transport Resource Reservations Channel Switching and HSPA Layering CQI Distribution HSPA Code and Modulation Usage HSPA Power Distribution MAC-hs Efficiency MAC-hs Retransmissions by Code and Modulation Usage Number of HSPA Users and UE capability NBAP Signalling RRC Signalling


Report ID RSRAN081 RSRAN083 RSRAN082 RSRAN076 RSRAN072 RSRAN064 RSRAN080 RSRAN031 RSRAN029 RSRAN030 RSRAN069 RSRAN075 RSRAN039 RSRAN034 RSRAN074 RSRAN040 RSRAN041 RSRAN051 RSRAN027 RSRAN038

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94516831 3G KPI Analysis Report

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