Multi Vendor Network Parameter Management

Whitepaper

Published: January 2007Revised: Rev A June 2007

Rev B October 2009 For more information , please visit :

http://www.aexio.com

Glossary

BSC BaseStationController

GPEH GlobalParameterEventHandler

MGw MediaGateway

MSC MobileSwitchingCenter

MTR MobileTrafficRecording

NMS NetworkManagementSystem

NOC NetworkOperationsCenter

OSS OperationsSupportSystem

RBS RadioBaseStation

RNC RadioNetworkController

UETR UserEquipmentTrafficRecording

UI UserInterface

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Contents1.Introduction......................................................................................1.1RadioNetworkOptimizationProcessess........................................ QualityManagementProcesses................................................. BasicQualityManagement......................................................... 1.2.1 DailyProcesses................................................................ 1.2.1.1WorstCellTrouble-Shooting........................................... 1.2.1.2NetworkParameterManagement.................................. 1.2.2 WeeklyProcesses........................................................... 1.2.2.1StatisticalPerformanceMonitoring................................ 1.2.3 MonthlyProcesses.......................................................... 1.2.3.1BenchmarkingIntegrityCheck(Optional)....................... EnhancedQualityManagement................................................. 1.2.4 Bi-weeklyAutomaticDriveTestReview............................ 1.2.5MonthlyCustomerDrivenNetworkQualityReview........ 1.2.6 YearlyOptimisationStrategyReview................................ SpecialisedQualityManagement...............................................

NetworkParameterManagement........................................................2.TheNeedforNetworkParameterManagement.............................. 2.1ManagingParameterConsistency......................................... FigureX:............................................................................ 2.2Intraandinterdepartmentalcoordination............................ FigureY:............................................................................ 2.3Rehoming.............................................................................. FigureZ:Rehomingexample............................................

3.HighLevelSolutionforNetworkParameterManagement..............

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IntroductionRadioNetworkqualityinacellularnetworkcanbeusedasabarometertogaugetheoverallqualityofanetwork.Thisisinalargepartduetothefactthatthemobilenetwork’squalityisdominatedbyasubstantialnumberofenvironmentalfactors.Bytrackingafewkeyperformanceindicators(KPIs)intheradionetwork,callqualityandsubscribers’perceptionofthequalityofthenetworkcanbemonitored.TheseKPIinclude,forexample,blockedcalls,droppedcalls,voicequalityandthroughput.

RadioNetworkOptimizationisgearedtowardsthemaximizationofcallqualityinalivemobilenet-workatanygivenpointintime,fromtheperspectiveoftheradionetwork.Byoptimizingtheradionetworkonadailybasis,subscriberscanenjoythebestcallqualityatwhateverstagethecellularnetworkisin–whetherduringexpansionormaintenancephases.

PartIofthiswhitepaperisageneralintroductiontotheRadioOptimizationProcessinagenericmobilenetworkOperator.ItattemptstodescribetheQualityManagementProcessforRadioOpti-mizationdepartmentsasaseriesofoverlappingprocesseswhich,inconcert,aimtomaintainandimprovQualityofServiceforthesubscribersfromaday-to-dayperspectiverightuptothemediumandlongerterm

PartIIwilladdressoneaspectoftheOptimizationProcesswhichdealswithmanagingkeyparam-eters inthemobilenetworkinamulti-vendorandmulti-technologyenvironment.ManagementoftheseparametersisthemostbasicrequirementtomaintainQoSinamobilenetworkenviron-mentwhichiseverdynamicintermsofitsgrowthandsubscribermobilityandformsthebasisforfurtherworktoimprovenetworkQoS.PartIIshowsthatfailuretoaddresstheseinconsistentparameterscanleadtodegradedQoSsuchasdroppedcalls.

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Radio Network Optimization

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1 Radio Network Optimization Processes

RadioNetworkOptimizationdepartments encapsulate this qualitydrivennetworkoptimizationprocess in their own departmental processes. Figure A below shows the quality driven radionetworkoptimizationprocessesdividedintothreelevelsaspicturedbelow:

FigureA:Genericqualitydrivenradionetworkoptimisationprocesses

Quality Management Processes

TheQualityManagementprocesscanbedividedinto3highlevelprocesses,definedhereas:1. BasicQualityManagement2. EnhancedQualityManagement3. SpecializedQualityManagement

InBasicQualityManagement,optimizationprocessesencompassactivities thatare required tominimallymaintainthenetworkqualityandprovideabasisforconsistentnetworkperformance.Suchconsistentnetworkperformanceisfundamentaltopreventingchurnduetonetworkqualityissues.

InEnhancedQualityManagement,optimizationprocessesareputinplacetoprovideadditionalquality improvements insteadofpuremaintenance. EnhancedQualityManagementprocessesinclude broad based strategies such as area based frequency / scrambling code planning andnetworkreviews.

InSpecializedQualityManagement,optimizationprocessesincludelaunchingofnewfeaturesandparameter tuningaswell as specialized task forces for areas such in-buildingsor key customerroutes.

ENHANCED QUALITY MANAGEMENTMonthlyNetworkQualityReviewbased

on customercomplaint

Bi-review andanalysisorGeo-coded

Yearlyreviewofnetworkpolicies,frequency/scramblingcodeplanning,

capacityreview etc.

SPECIALIZED QUALITY MANAGEMENT

complaints New Service launch

BASICQUALITY MANAGEMENTDailyConsistencyCheck,

ReviewMonthlyBenchmarking

IntegrityCheckDailyWorst Cell

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Basic Quality Management

1.2.1 Daily Processes

1.2.1.1WorstCellTrouble-Shooting

Onadaytodaybasis,worstperformingcellsinthenetworkneedtobeidentifiedandrootcausesforsuchlowperformanceinvestigated.Theprocessoftroubleshootingthesecellsensuresthatonadailybasis,highprioritycellswithQoSissuesarealwaysmonitored.Whilstthismayseemanoperational issue,optimizationorqualitydepartments,astheprimarypartyresponsiblefornetworkquality,needtoalsoensurethatthereisalwaysasolutionavailabletosolvethesecauseofnetworkqualitydegradation,beitanoperational(suchasahardwarefix)oroptimizationactivity(suchasascramblingcodeorparameterchange).

1.2.1.2NetworkParameterManagement

NetworkParameterManagementandtheunderlyingactivityofparameterconsistencycheckingisdonetoensurethatparameterssuchasneighbordefinitionsareconsistentwithintheBSS(in-tra-andinter-BSCorRNC)andbetweentheBSSandcorenetwork(BSC/RNCtoMSC)evenasthenetwork continuously changes fromday today to siteexpansions, re-homingandoptimizationwork.ConsiderableproblemsdoarisefrominconsistentparametersettingsintheBSSdatabaseandcorenetworkwhichcancausehandoverfailuresanddroppedcalls. Insinglevendorenvironments,alargepartofthiscanbetakencareofwithinternalconsistencycheckswhicharepartoftheNMSsoftwarepackageandshouldberundaily.Inamulti-vendorenvironment,astheformatsforpa-rameterdatabasesarenotstandardized,thisisdoneviainternalmacros,custommadesoftware,aninternalprocedureor,insomecases,notatall.

1.2.2 Weekly Processes

1.2.2.1StatisticalPerformanceMonitoring

ThisprocessinvolvesthemonitoringofstatisticsfromthecorenetworkandtheBSSonaweeklybasis.RawcountersfromboththeswitchesandeventheRBSnodesareaggregatedtoprovidestatistical information on a variety of areas from call setup and handover performance to callterminations.Optimizationengineersusethisinformationtoidentifyworstperformingcellsinthenetworkandwiththeappropriateanalysisofbasecounters,areabletoidentify,insomecases,therootcauseoftheproblemcells.StatisticalinformationisusuallyprovidedbythenetworkequipmentvendorfromtheirNetworkManagementSystem(NMS)or3rdpartysolutions.

1.2.3 Monthly Processes

1.2.3.1BenchmarkingIntegrityCheck(Optional)

Insomecases,Operatorsalsooptformonthly(orquarterly)benchmarkingexercisesbasedondrivetestdata.DataandreportingfromsuchexercisesallowstheOperatortomeasuretheircompetitivenessintheirregionsorcountries.Incertaincases,andmoresointhepresenttime,marketregulatoryrequirementsoftenstatesbenchmarkingasanecessarypartoftheOperator’sactivitieswhichisthenusedtoensurecompliancewithlocalregulationsandpolicies.

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Enhanced Quality Management

EnhancedQualityManagementProcessesarethoseprocesseswhichareneededtobedonetointroducemoreproactivequalitymanagement.Itinvolvesobtainingmoreperspectivesonqualityissuessuchasobtainingandreviewingcustomercomplaintdataaswellasstrategicplanningforcopingwithcapacityincreasesinthemediumterm.Thefrequencyofsuchactivitiesvary,withthefollowingprovidingapragmaticapproachinatypicalOperatorenvironment.

1.2.4 Bi-weekly Automatic Drive Test Review

Whilst network statistics provide a quick view of network performance, it is difficult tounderstandthe(individual)subscriber’sexperienceofthenetwork.AssumingthatanOperator’ssubscriberssignificantlyutilisetheirmobilesontheroad,drive-testingprovidesaverygoodideaofasubscriber’sexperienceiftheQoSissuesaregeo-locatedinthesamevicinity.AutomateddrivetestsprovidehughamountsofdatawhichcanbeusedtoidentifytheseQoShotspots.Withtheadventofgeo-locatedmobiletrafficrecordings,thiswouldbeanotheravenuetoidentifysuchQoShotspotswhichimpactsubscriberperceptionofthenetwork.

1.2.5 Monthly Customer Driven Network Quality Review

Whilstinthepast,CRMsystemshavebeendisjointfromOptimization,moreandmoretodaythequalitymanagementprocesses includedirect feedback fromtheCRMsystem.Customerticketsprovidearelevant inputtotheoptimizationprocessbyhigh-lightingweakspots inthenetworkandprioritisingproblems thatneed tobeaddressedwithurgency.ACustomerdrivenNetworkQualityReviewaimstodojustthatbyensuringareas,whethergeographical,logicalorprocessesarecontinuouslyreviewedandimproved.

1.2.6 Yearly Optimisation Strategy Review

On a yearly basis, as the network expands and grows, it is important to always review andupdate optimization policies and strategies. Such reviews and audits ensures that the optimi-zationdepartmentcankeeppacewithnetworkgrowthtoalwaysmeet itsprimaryobjectiveofmaximizingqualityforthesubscribers.

Specialised Quality Management

SpecialisedQualityManagementProcessesarethoseprocesseswhichareaimedatlookingatthelongertermqualityorcapacityissuesofthenetwork.FeatureandspecificParameterTestingaswellasnewServiceLaunchesfallintothiscategory.Theseprocessesarenotdailyprocessesbutarerequiredonanad-hocbasiswhennetworkqualityorcapacityissuesdemand.Thesead-hocprocessescanbelaunchedwhen,forexample,theyearlyoptimizationStrategyReviewindicatesaneedforthem.OtherprocessesuniquetoeachOperatorsuchasVIPRouteTroubleshootingwillalsofallundertheSpecialisedQualityManagementProcesses.

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PART II

Network Parameter Management

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2 The Need for Network Parameter Management

NetworkParameterManagement fulfils theneed inadynamicnetworkenvironmenttoensurethatparametersinthecellularnetworkareconsistentwithinvendors,betweenvendorsandalsobetweentechnologiessuchas2G,3Gand3.5G.

The followingproblemdescriptionsand scenariosexplain inmoredetail theneed forNetworkParameterManagement.

2.1 Managing Parameter Consistency

Onaday todaybasis, theparameterdatabases innetworknodesare constantlyupdatedandmodifieddue tooperational issues andoptimizationwork.Astimegoesby, asparameters aremodified,inconsistenciescancreepintothedatabaseduetooverlappingactivities,thedifficultyofcoordinatingacrossdepartmentsandsometime,simplehumanerror.

Takeasimplescenariooutlinedhere.

AnetworkconfigurationasseeninFigureXbelowisdescribed.

Figure X:

TheexamplenetworkconfigurationisaNokia2G/3GRANnetworkconnectedtoaSiemensMSCandanEricsson3GRANconnectedtoanEricssonMSC.

When implementing a simple parameter modification, for example, a (Ericsson) neighbouradditiontoaNokia2Gcell,multiplestepsneedtobedonetobeimplemented.1.AddtheEricssonneighbourtotheNokiaCellneighbourlistasa2wayneighbourwithcorrectlydefinedBCCH-BSIC2.Ifundefined,createanexternalcelldefinitionintheEricssonRNC.3.AddtheNokiaCelltotheEricssonneighbourasa2wayexternalcell.4.IfundefinedintheMSClevel,addtheLACforthetargetcells.

3G

Ericsson Nokia3G

2G

Siemens MSCEricsson MSC

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Up to 4 steps is required for updating a single parameter due to the requirements of eachvendorandthetechnologytype.Withmanyparametersbeingupdatedeveryday,thepossibilitythatsomeerror ismade in thisprocess ishigh.Furthermore,conversionofchangerequests toMMLscriptsis,byandlarge,amanualprocesswhichisalsopronetoerror.ThecomplexityandnumberofMMLscriptsrequiredalsoincreasewiththenumberofincreasingnodes,technologytypesandvendors.Failuretomanagethissituationcanleadtoaninconsistentparameterdatabasewhichcanleadtomoredroppedcallsinthesystem.

OneofthesoftwaresolutionstomanagethiswouldbetoautomatethecreationofallMMLscriptsforallparameterchangescenarios.However,itisintheopinionofthisauthorthatsuchasystem,ifconceived,wouldbehighlyexpensiveduetotheverylargenumberofscenariospossible.Thealternativeistousesoftwaretoonlydetectandcorrecttheinconsistentparametersinthesystem,aso-calledcheckandbalanceforthenetwork.

2.2 Intra and interdepartmental coordination

Hereisanotherexampleofapossiblescenariothatcouldleadtoinconsistentparametersinthenetwork.

Figure Y:

Inatypicaloperatorenvironment,optimizationengineersareresponsibleforspecificareas/ven-dorsand/ortechnologies.InthecaseinFigureY,RalphistheOptimizationengineerforEricsson3GandJohn,forNokia2G-3G.

Inaday,RalphmaychoosetooptimiseAreaAattheborder,changingparametersbasedonhisunderstandingofthenetworkatthetime.HemayhavealsoalreadycommunicatedwithJohnwhowouldhavetoldhimthathehasalreadychangedcertainparametersattheNokiaborder,whichheassumedhadbeenchangedastheywerepreviouslysubmitted.RalphmayproceedtosubmithisChangeRequesttooptimizehisborderareas.AtOperations,bothChangeRequestsareimple-mented,however,notnecessarilyintheorderthatbothRalphandJohnenvisaged.Asthereisnoin-builtmulti-vendorcheckattheOSS,bothEricssonandNokiasystemsacceptthechanges.

2G

3G3G

Ralph John

Area A Area BOPERATIONS

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Whilst sucha scenariomay seem trivial, such changesdo introduce inconsistencies in thenet-work.Ifthechangedoesnotimmediatelycauseanydroppedcall,aseriesofuncoordinatedeventssuch as this can lead to parameter databaseswhich are very inconsistent and loweredQoS inthe long run.As theQoSdegradesgradually,departmentsdonot immediatelydetect that it isinconsistenciesintheparameterdatabasethatisthecause.

There are 2 ways of managing this. The first would be strict adherence to intra and interdepartmentalprocessesandcommunication.However,evenwithsuchdiscipline,itisstillpossibleforerrorstobemade,asinanycomplicatedprocess.Amorepragmaticapproachthenwouldbetohaveacheckandbalancesystemthatcandetectwhensuchinconsistenciesoccurinthenetwork.

2.3 Rehoming

Inanotherscenario,arehomingexerciseiscarriedoutasinFigureZbelow.

Figure Z: Rehoming example

Therehoming(orreparenting)exerciseforoperatorsoccursduringtheearlymorningmaintenancewindoworwhenthetrafficis lowestsoasnottodisturbsubscribers,whoexpectnochangeintheQoStheyreceive.However,thisisnotalwaysthecaseasintheprocessofcellsmigratingtoa newBSC (or RNC), a large number of reconfiguration changes aremadeboth physically andconfiguration.Carefulchecksneedtobeperformed inbothareas. Inthe latter,a largenumberparametersneedtobecarefullycheckedtoensureconsistencyinthenewnetworkconfiguration.Thisisanotherareawhereanetworkparametermanagementsolutionincorporatingconsistency checksisuseful.

2G Cells

3G

Ericsson Nokia3G

2G

Siemens MSCEricsson MSC

BSC A BSC B

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3 High Level Solution for Network Parameter Management

Anadequatesolutionfornetworkparametermanagementwhichensuresconsistentparametersinthemobilenetworkshouldhavethefollowingfeatures:

•BefullyautomatedforscheduleddailychecksParametercheckingneedstobedonedailytoensureparametersareconsistentevenwithnewsitescomingonairand/oranynetworkchangesoccurringduringthepreviousnighthours.

•Bedepartmental-wideorenterpriselevelAlloptimizationengineersandmanagersshouldhaveaccesstotheparametersoftware.Inan ideal situation,otherdepartments couldhaveaccesswithdifferentauthorities set fordifferentgroupsofusers.

•Bemulti-vendorandmulti-technologyThe software has to have the ability to check parameter consistency between as manyvendorsandtechnologiesaspossible.

•EasytouseThesoftwareshouldbeintuitivetouseforanoptimizationengineer.

•ProvidecellhistoriesCell histories provide optimization engineers the history of parameter changes in thesystem.Thishelpsinplanningoptimizationstrategiesandprovidesacheckandbalanceforinter-departmentalprocessesbetweentheOptimizationdepartmentandtheNOC.

•ProvideexcellentreportingandexportpackagesWith a strong reporting package, Optimization Engineeringmanagement can control thechangesintheparameterdatabaseanditsimpactonthenetworkquality.WithexportstovariouseasilyavailableformatssuchasExcel,Optimizationengineerscandomorepost-pro-cessing,ifrequired,fortheirownanalysis.

•Semi-orautomatedinconsistencycorrectionsApart from detecting inconsistencies, a good solution will need to be able to correctinconsistencieseitherinasemi-automatedorautomatedmanner.Semi-automatedsolutionswillservethechangemanagementprocessbetterwhereitprovidesanapprovalpointforengineerstoconfirmtherecommendedchangesareinlinewiththeirengineeringdesign.

•InherentlysupportchangemanagementSupport for change management is a pre-requisite. With in-built change requestmanagement,thesolutioncanautomaticallycontrolunauthorizedchangestoimportantpa-rameters(optimizedparameters)inaclosedloopmanner.

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