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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