performance monitoring & kpi improvement workflows

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Performance Monitoring & KPI Improvement Workflows LEO.AJ

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Page 1: Performance Monitoring & KPI Improvement Workflows

Performance Monitoring & KPI Improvement Workflows

LEO.AJ

Page 2: Performance Monitoring & KPI Improvement Workflows

Performance Management….

• Performance management is the process and procedures involved in ensuring that a network operates at maximum efficiency and to the defined Quality of Service (QoS) levels throughout its lifetime. In order to carryout this function a number of tools have been designed to assist both network managers and network engineers.

• The Key Functionalities of Performance management are:-• Ongoing process to monitor network performance• Sustains network quality throughout its lifecycle by proactive maintenance• Reduces risk of network degradation• Improve network performance through optimisation techniques• Support business interests of the network operator

• Poor maintenance procedures lead to network performance degradation resulting in:

• Reactive fault rectification• More complaints from customers• Customer churn• Reduced profit margins• Weakening of operator’s business position

Page 3: Performance Monitoring & KPI Improvement Workflows

Performance Management….

• PERFORMANCE DATA SOURCES:

• Performance Data can be obtained from a number of sources including:

– Drive Tests

– Statistical Measurements:

– MSC data

– Databases (HLR/VLR)

– BSS data (BTS/BSC)

– Customer Complaints

– Field Engineer Reports

Page 4: Performance Monitoring & KPI Improvement Workflows

KPI’s

• KPI’s: KEY PERFORMANCE INDICATOR DEFINITION’S

– CSSR: This is defined as the ratio of successful calls to attempted calls. This formula calculates the proportion of mobiles which successfully access a TCH.

• CSSR % = (Succ TCH Seizures / Attempted TCH Seizures) X 100

– TCH Blocking: TCH Blocking is the ratio of blocked TCH Seizure attempts to that of all attempted TCH Seizures.

• TCH Blocking % = ( Blocked TCH Seizures attempts/Attempted TCH Seizures) X 100

– SDCCH BLOCKING: SDCCH Blocking is the ratio of blocked SDCCH Seizure attempts to that of all attempted SDCCH Seizures.

• SDCCH Blocking % = ( Blocked SDCCH Seizures attempts/Attempted SDCCH Seizures) X 100

– TCH Assignment Failure Rate (excluding blocking) is the rate of TCH seizure failed (system + radio) during normal assignment procedure over the total no of TCH requests for normal assignment procedure. It is mostly expressed as a %ge.

• TCH Assignment Failure Rate = ( Failed TCH Seizures / TCH Assignment Requests) X 100

Page 5: Performance Monitoring & KPI Improvement Workflows

KPI’ s Cont….

– DCR: Drop Call Rate calculates the proportion of mobiles which, having successfully accessed the TCH, subsequently suffer an abnormal release, caused by loss of the radio link. This figure is comprised of RF Losses on the TCH plus losses during handover.

• DCR % = ( Total Abnormal Release/ (Successful TCH Seizures + Intra cell HO + Inter cell HO) X 100

– CSR: Call Success Rate Single overall figure for network quality from a subscriber’s perspective which represents the proportion of calls which complete successfully i.e. Set-Up successfully and do not suffer an RF loss before user termination or successful hand out.

• CSR % = CSSR %ge * (1- DROP CALL RATE)

– HSR: The HANDOVER SUCCESS RATE statistic tracks the percent of handovers that were attempted from the source cell (cell for which the statistic is presented) that succeeded in making it to the destination cell.

• HSR % = (succ Outgoing Internal Inter Cell HO / att Outgoing Internal Inter Cell HO ) X 100

Page 6: Performance Monitoring & KPI Improvement Workflows

INTRODUCTION TO KPI MONITORING

In KPI Monitoring following points are important:-•KPI definitions must be accurate and audited for usage•KPI Trends must be prepared on a weekly, Monthly and daily basis•KPI data collection should be made for suitable duration to identify issues

Page 7: Performance Monitoring & KPI Improvement Workflows

Performance Monitoring:

• Daily:

– Daily Performance Monitoring focuses on assessing and identifying issues that need immediate attention.

• Weekly:

– Weekly reporting should be done for a weekly performance evaluation of the network.

• Monthly:

– Monthly reporting should be done for generating KPI trending and strategically implementing Network changes or expansions

• All KPI reports need to be monitored at the following different levels:

– Cell Level

– BSC Level

– Network Level

Page 8: Performance Monitoring & KPI Improvement Workflows

Performance Monitoring Data Inputs:

• Performance data can be collected from the following different sources. Following KPI’s need to be given special attention:

» Call Setup Success Rate

» Assignment Failure Rate

» Drop Call Rate- TCH & SDCCH

» Handover Success Rate- Intra & Inter

» TCH & SDCCH Blocking

• These stats can be collected from the following different sources:-

» KPI Statistics

» Drive Test Field Report and Post Processing data

» Customer Complaints

» Performance tools in OMCR in Uplink, Downlink and call trace data

Page 9: Performance Monitoring & KPI Improvement Workflows

KPI Analysis Phase:• The Purpose of the analysis phase is to identify all the prevalent issues in

the network that need attention. This phase consists of the following different checks to identify the cause of poor performance on the cells:-

– Consistency Checks

– Parameter Verification

– Drive tests log analysis

– Physical Site Audits

– Feature Verification

– Depending on the analysis several recommendations may be done to improve network stats like:

– Mechanical tuning

– Frequency Plan changes

– Neibour Plan Changes

– Hardware changes

– Feature enabling &

– Parameter changes

Page 10: Performance Monitoring & KPI Improvement Workflows

Dropped calls on TCH

Check dropped call reason

Bad quality?

Low signal strength?

Most dropped calls during handover?

Check lost handovers

Perform interference analysis with MRR

and/or FAS

Perform low signal strength analysis

Perform handover analysis

Swap & repair HW

Check site position

Site covering too much?

Check MS fleet

Best server exists?

Check radio network features

Power regulation

used properly?

DTX used?

Check output power

Check locating parameters

Bad parameter setting?

Check antenna installation

Perform site survey

Check BTS error log

HW fault?

Transmission fault?

Check link quality

Power balance? Adjust output power

Introduce DTX

Correct parameter setting

Frequency hopping used?

Remove site or change frequency

Perform link investigation

Activate frequency hopping

Add site

Perform MTR/CTR/MRR etc. recordings

Perform drive tests

High timing

advance?

END

F

F

Check site location & TALIM

NO

Correct power regulation parameters

YES

NO

YES

YES

NO

NO

YES

YES

NO

NO

YES

YES

NO

YES

NO

YES

NO

NO

YES

NO

YES

YES

NO

NO

YES

Missing neighbours suspected?

Run NCS YES

NO

iInterference? Check frequency plan,

external interferers and/or filters

YES

NO

Drop Call Rate:Optimisation Flowchart

Page 11: Performance Monitoring & KPI Improvement Workflows

Check TCH congestion

Low TCH assignment success rate

Congestion

on TCH?

Check output power, check if cell reachestoo far by TA distribution with MRR

Low output power? Check output power

parameters

Wrong parameter

setting?

Check signal strength of

BCCH and TCH

Low SS for call

access?

Check BTS Error Log

HW fault?

NO

YES

END

Rectify parameters

Contact NMC toswap & repair HW

Check coverage plots

Perform drive tests

Dominant

server exists?

YES

NO

YES

Add BTS NO

Add transceivers and/ortune Assignment to other

cell and CLS.

YES

NO

YES

YES

NO

Adjust TCH output

power

NO

Check interference withICM, FAS and/or MRR

Disturbance

on SDCCH or

target TCH?

Improve & adjust

frequency plan

NO

YES

Improving TCH Assignment Success rate

Page 12: Performance Monitoring & KPI Improvement Workflows

Collect statistics

Change parameter value

Update parameter recommendations, write report

if required

More parameter values to be tested?

Parameter differs from par. rec. and/or par. log?

Evaluate statisticsCompare with the pre-analisis

result

Recommended value(s) to be changed?

Yes

Yes

No

No

No

Update parameter logYes

FINISH

PRE-ANALYSIS

Parameter Tuning Workflow

Page 13: Performance Monitoring & KPI Improvement Workflows

Feature enabling workflow:

2. Proposal

no yes

5. Field Trial

7. Activation

8. Follow-up

9. Documentation

6. Go

ahead?

noyes

3. Field

trial?

1. Select

Feature

Page 14: Performance Monitoring & KPI Improvement Workflows

SDCCH

congestion

Check site position

Location area border?

Change locationarea border

Check andincrease CRH

Check TCH traffic

TCH Congestion?

Check SMS activity

Many SMSmessages?

Check channel configuration

Same for allcells in area?

Check traffic trend

Short termtraffic growth?

Check SDCCH dimensioning

D

D

Underdimensioned

SDCCH?

Check SDCCH mean holding time

Long meanholding time?

Check periodic registration

Too frequentregistrations?

Is cellbroadcast

used?

Check HWavailabilty

Low availability?

See TCH & SDCCH

availability

Avoid cell broadcastif possible

Change channelconfiguration

Add TCHcapacity and/orAssignment to

other cell or CLS

Consider changingregistration interval

timers

No activity

Check HW and number

of false accesses

RedimensionSDCCH

END

YES

NO

NO

NO

NO

NO

YES

NO

NO

NO

NO

YES

YES

RedimensionSDCCH

1

YES

YES

YES

NO

YES

YES

YES

YES

SDCCH Congestion Improvement Plan.

Page 15: Performance Monitoring & KPI Improvement Workflows

NO

END

SDCCH & TCH

availability

Transmission problem?

Missing SW correction?

Contact NMC toload correct SW

HW fault?

Capacity problem?

Perform more investigations

NO

NO

YES

NO

NO

YES

YES

YES

Cell basebandhopping?

Check transmission

Check loaded SWAdd transmission

capacity

Change or repairtransmission equipment

Check that NUMREQBPCis set to SYSDEF and thatnumber of frequencies is

correct

YES

HW problems? YES

Check BTS Error log

Replace & repair faulty HW

YESCell synth hopping?

Check NUMREQBPC(RLBDP), set to number

of channels

NO

NO

Improving TCH & SDCCH Availability

Page 16: Performance Monitoring & KPI Improvement Workflows

High RACH FAILURE

Check BSIC allocation

Check frequency plan

Access burst from another co-channel cell

Check cell parameter setting

MAXTA too low?

Check SAE

Software file congestion?

Check ICM, run FAS if needed

High noise floor?

END

Reduce interference

Increase SAE

Increase MAXTA

Change BSIC or frequency plan

Check if unknown access code

YES

NO

NO

YES

NO

YES

NO

YES

Check site location

High located site? Consider tilting or

lowering site

NO

YES

Improving RACH Success Rate

Page 17: Performance Monitoring & KPI Improvement Workflows

Handover

analysis

Check successful handovers per cell

Success below x%?

Check handover activity

More than x

handovers

performed?

Check handover flow

Check site location

Important cell?

Uneven flow?

Difference in

performance in out-

and incoming?

Focus on bad direction

E

Check if K or L locating is used

E

Select worst relation

External?Start Inter-BSC/MSC

analysis

High ratio of

urgency

handovers?

High ratio of lost

handovers?

YES

YES

YES

YES

YES

NO

NO

YES

Check if many ping-pong

handovers

Check if assignment handovers

are used

END

Check if cell has HW problems

Check if congested target cell

Perform measures to

improve performance

Check SAE

Check handover related parameters such as relations,

missing relations (using NCS), BA-list, BSIC,

hysteresis, offsets, etc.

NO

NO

NO

Next cell

High ratio of

retensions?

NO NO

Check up- and down link interference with

MRR, FAS ICM, TEMS

Check frequency plan

YES YES

Improving Handover Success Rate

Page 18: Performance Monitoring & KPI Improvement Workflows

CSSRCSSR might be affected and degraded due to followingissues:

– Due to radio interface congestion.– Due to lack of radio resources allocation (for instance: SDCCH).– Increase in radio traffic in inbound network.– Faulty BSS Hardware.– Access network Transmission limitations (For instance: abis expansion restrictions)

Analysis & Findings:Following methods are used to diagnose CSSR degradations as well as improvements– Radio link Congestion statistics monitored using radio counter measurement. – Drive Test Reports. Customer complaints related to block calls have been reviewed.

Improvement Methodologies:Following measures significantly improve the CSSR in live network:

– Radio Resources enhancement (Parameter modification/changes in BSS/OMCR) such as • half rate, • traffic load sharing and • direct retry parameters implementation.

– Transmission media Expansion to enhance hardware additions (such as TRX).– Faulty Hardware Replacement (such as TRX) in order to ensure the resources availability

in live network.

Page 19: Performance Monitoring & KPI Improvement Workflows

THANK YOU!!