车载网络flexray调度方案优化设计分析

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1、浙江大学硕士学位论文AbstractWiththedevelopmentofX—by—wiresystem．TraditionalvehiclebusnetworkssuchasCAN，LINandetc，fortheirowninherentcharacteristicsoflowbandwidth，unpredictabilityandetc，areunabletomeettherequirementofhighbandwidth，reliability，fault—toleranceinnextgenerationX—by—wiresystemappli

2、cation．Therefore，thenew—vehiclenetworkbuscalledFlexRaycomesintobeing．FlexRayprotocolisdevelopedbytheFlexRayConsortiumwhichisformedbyBMW，Daimler—Chrysler，Freescale，Bosch，Philipsandetc．in2005，FlexRayConsortiumreleasetheV2．1versionoftheFlexRayprotoc01．Now，productsrelatedtoFlexRayhasbee

3、nsuccessfullyapplledtosomecarsofBMWandAudi．FlexRayprotocolisconstitutedbythestaticsegmentwhichisbasedonTimeDivisionMultipleAccess(TDMA)andthedynamicsegmentwhichisbasedonFlexibleTimeDivisionMultipleAccess(FTDMA)．Cyclicmessagesaretransmittedinthestaticsegmentandsporadicmessagesaretran

4、smittedinthedynamicsegment．Therefore，CreatingthestaticschedulingtableinthestaticsegmentandhowtoassignFIDtoeverydynamicmessageinthedynamicsegmentarecriticalfortheperformanceofanefficientFlexRay—basedsystem．ThepapermainlyfocusonschedulingoptimizationofthestaticanddynamicsegmentofFlexR

5、ay．WefirstlyanalysistheFlexRayprotocolinthispaper，includingthebasiccharacteristic，operationcontrol，thetopologyandetc．basedontheanalysis，westudyonthereal—timeschedulingprobleminthestaticsegment．Selectingbandwidthutilizationastheperformancemetrics，wetransformthesignal—’packingproblemi

6、ntothebin—。packingproblemwithconstraints，andsolvetheproblembyFFDalgorithm．Fortheveryfewlongsignaldata，weproposeasignal—splitmethodtospiitlargesignaldataintoshortsignals，whichimprovethebandwidthutilization．Finally，III浙江大学硕士学位论文Abstractbasedonthesignal—packing，weuseFIDmultiplexingmeth

7、odtominimizethenumberofFIDstobeused．Inthedanymicsegment，wefirstlyanalysisthewrostcaseresponsetime(WCRT)ofthedynamicmessages．Basedonthis，westudyontheschedulingproblem．Toreducetheresponsetimeofdynamicmessages，weselectthelengthofthedynamicsegmentasthesummationofallthedynamicmessages．Th

8、en，aheuristicalgori