performance monitoring & kpi improvement workflows

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Performance Monitoring & KPI Improvement WorkflowsLEO.AJ

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 operators business position

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

KPIs KPIs: KEY PERFORMANCE INDICATOR DEFINITIONS 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

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 subscribers 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

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

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

Performance Monitoring Data Inputs: Performance data can be collected from the following different sources. Following KPIs 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

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

Dropped calls on TCHF

iInterference?

YES

Check frequency plan, external interferers and/or filters

Check locating parameters

NO

Drop Call Rate: Optimisation Flowchart

High timing Bad parameter setting?NO YES

Correct parameter setting

advance?NO

YES

Check site location & TALIM

Check lost handovers

Check radio network features Most dropped calls during handover?NO YES

Power regulation used properly?YES

Perform handover analysis

Correct power regulation parametersNO

Check site position

Check output power Site covering too much? Power balance?YES NO

YES

Remove site or change frequency

Adjust output powerNO

Check BTS error logNO

DTX used?YES

Introduce DTX HW fault? Activate frequency hoppingNO YES

Swap & repair HW

Frequency hopping used?YES

NO

Check link quality

Check dropped call reason

Transmission fault? Perform interference analysis with MRR and/or FAS

YES

Perform link investigation

Bad quality?NO

YES

NO

Best server exists? Perform low signal strength analysis

NO

Add site

Low signal strength?

YES

YES

Check MS fleetNO

Perform drive tests Missing neighbours suspected?NO F YES

Run NCS

Perform MTR/CTR/MRR etc. recordings Perform site survey Check antenna installation END

Low TCH assignment success rate

Check TCH congestion

Improving TCH Assignment Success rateYES

Congestion on TCH?NO

Add transceivers and/or tune Assignment to other cell and CLS.

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

Low output power?

YES

Check output power parameters

Wrong parameter setting?

YES

Rectify parameters

NO NO

Check BTS Error Log

Check signal strength of BCCH and TCHNO

HW fault?

YES

Contact NMC to swap & repair HW

Low SS for call access?

NO YES

Check coverage plots Adjust TCH output power Perform drive tests

Dominant server exists?

NO

Add BTS

YES

Check interference with ICM, FAS and/or MRR

Disturbance on SDCCH or target TCH?

YES

Improve & adjust frequency plan

NO

END

Collect statistics

Parameter Tuning WorkflowPRE-ANALYSIS

Change parameter value

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

Yes

Update parameter log

No Evaluate statistics Compare with the pre-analisis result

Yes

More parameter values to be tested?

No Recommended value(s) No be changed? to Update parameter recommendations, write report if required

Yes

FINISH

Feature enabling workflow:1. Select Feature 2. Proposal

no

3. Field trial?

yes

5. Field Trial

yes 6. Go ahead? 7. Activation

no

8. Follow-up

9. Documentation

D

SDCCH congestion

Check channel configuration

SDCCH Congestion Improvement Plan.Change channel configuration

Check HW availabilty Low availability?NO

Same for all cells in area? See TCH & SDCCHYES

NO

YES

availabilityIs cell broadcast used?YES

Avoid cell broadcast if possible

Check site position Check and increase CRH

NO

Location area border?

YES

Check traffic trend

YES

NO

Change location area border

Short term traffic growth?

YES

No activity

Check TCH traffic TCH Congestion?NO

NO

YES

Add TCH capacity and/or Assignment to other cell or CLS

Check SDCCH mean holding time

Check SMS activity

Long mean holding time?

YES

Check HW and number

of false accesses

Many SMS messages?NO

YES

Redimension 1 SDCCH

NO

Check SDCCH dimensioning

Check periodic registration

Underdimensioned

YES

SDCCH?NO

Redimension SDCCH

Too frequent registrations?

YES

Consider changing registration interval timers

END

NO

D

SDCCH & TCH availability

Cell synth hopping?NO

YES

Check NUMREQBPC (RLBDP), set to number of channels

Improving TCH & SDCCH Availability

Cell baseband hopping?NO

YES

Check that NUMREQBPC is set to SYSDEF and that number of frequencies is

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