vehicle-to-vehicle wirelesscommunication protocols foren：车辆无线通信协议公开辩论的课件

Vehicle to VehicleWirelessCommunicationProtocolsforEnhancingHighwayTrafficSafety AComparativeStudyofDataDisseminationModelsforVANETs Presentation NickFrangiadakis SubirBiswas RaymondTatchikou FrancoisDion TamerNadeem PravinShankar LiviuIftode Cheap embeddedprocessorsCheap embedded smallsensorsInterconnectedMobileUbiquitousComputingNewservices applications Towardsthefuture Wireless Towardsthefuture Anumberofdiverse ornot technologies 802 11a b g e GSM UMTS DSRCAnumberofdifferentproblems applications services AnevengreaternumberofsolutionsExerciseforthereader EachofthediscussedtechnologiesaddressbestadifferentsetofproposedapplicationsSurvivalofthebest Notalwaysthecase Survivalofthefittest Alreadydeployedorcheaperorevensupportedfromthelargestcompany Butthisisasystemsproblem Notso orbetternotonly Vastnumberofsensors AlotofDataDistributedPossiblyMobileQueriesaboutthedataMostapplicationsinfactaredata centricInternetcouldalsobeseenasasystemsproblem butthereisalsoe g Google sperspective Anapplication Thesis TrafficsafetyisanapplicationthatweWILLseeinthenearfuture ThetechnologyusedIStheonethatwillbediscussed Thismeansthatthetechnologydiscussedwillbeinplaceinthenearfutureandwillprobablybeusedformoreapplications VANETS Vehicle to VehicleWirelessCommunicationProtocolsforEnhancingHighwayTrafficSafety CCA CooperativeCollisionAvoidance UnitedStates sixmilliontrafficaccidents year2003 230billion 2 889 000injuries 42 643deaths5 850to5 925GHzbandallocatedbyUSFCC CAC ApplicationExamples HighwayaccidentsAutomaticallyadjustingcruisecontrolBeaconforstoppedcars policeAccidentsfromRedlight StopviolationsIngeneralAvoidhumanerrors 90 ofalltrafficaccidents CCA CooperativeCollisionAvoidance CCA CooperativeCollisionAvoidance Thegeneralpicture proposednationalinfrastructure Thegeneralpicture proposednationalinfrastructure DSRC DedicatedShortRangeCommunication MAC Defactostandard 802 11Stabilityproblems e g TDMAisverydifficult PacketForwardingTimetoestablishconnectionistimelostMANETstylenotapplicable e g AODVdoesnotwork Broadcastoriented data driven packetforwardingbasedongeographiccontext Context awarepacketforwarding DirectionAwareBroadcastForwardingDesigntargets minBandwidth limitcollisions prioritizedata Whatarethelimits Na veBroadcastIntelligentBroadcastWithImplicitAcknowledgment Others Context awarepacketforwarding Somenumbers Context awarepacketforwarding Somenumbers Context awarepacketforwarding Somenumbers Context awarepacketforwarding Somenumbers Context awarepacketforwarding Somenumbers SomemorePoints With80 kb s vehiclebackgroundtraffictheprotocolcanstillwork Broadcast intelligentwithprioritiesProblemsimilartoSensorNetworkproblemsforwhichtherearemodelsandbounds e g TheCapacityofWirelessNetworksPiyushGupta P R Kumar 1999 Mobility DataDriven Priority txspeed AComparativeStudyofDataDisseminationModelsforVANETsTamerNadeem PravinShankar LiviuIftode VANETsenableanewclassofapplicationsthatrequiretime criticalresponses lessthan50ms orveryhighdatatransferrates 6 54Mbps Thedisseminationmechanismcaneitherbroadcastinformationtovehiclesinalldirections orperformadirectedbroadcastrestrictinginformationaboutavehicletovehiclesbehindit TrafficView TrafficView GPS OBD Storedmapsetc OBD OnBoardDiagnosis Dataaggregation Periodicallybroadcastallstoreddata Prototype evaluationofsimulationinns2Withoutlossofgenerality weassumevehiclesmoveonbidirectionalstraightroadswithmultiplelanesineachdirection Disseminationmodels Analysis Latencytime L isdefinedasthetimeneededtopropagategenerateddatabetweentwovehiclespositionedDmetersfromeachother Broadcastutilization U isdefinedasthepercentageofthenewlycoveredareabythecurrentbroadcast whichisnotcoveredbyanypreviousbroadcastofthesamedata tothetotalareacoveredbyabroadcast Analysis Latencytime L isdefinedasthetimeneededtopropagategenerateddatabetweentwovehiclespositionedDmetersfromeachother Broadcastutilization U isdefinedasthepercentageofthenewlycoveredareabythecurrentbroadcast whichisnotcoveredbyanypreviousbroadcastofthesamedata tothetotalareacoveredbyabroadcast Simulation LatencyTimeUtilizationrateKnowledgePercentage Foreachregion thepercentageoftheknownvehicle