文档介绍：://&ConclusionFutureWorkQ&,FHSSorIRPHYMACprovidesCSMA/CAthroughNAV(~’CS’)Basic&RTS/essesCongestion,timingand backoffmechanismsOnmodelingDCF-> Bianchi;Wu,-wayhandshakingAssumesthatthereisnoothertransmissionduringthisslot!!!Whatifthereisahiddenstation???ABCDSaturationThroughputModelBianchiprovidesasaturationthroughputmodelbasedonaMarkovmodelofbackoffmechanism- essE[P] Pidles+essTs+PcollisionTcPidle=1-ess=PtrPsPcollision=Ptr(1-Ps)Ptr=1–(1–t)nandPs=nt(1–t)n-1/essfultransmissionandcollidedtransmissionS=HiddenStationModel-StaticKleinrockandTobagi’shearinggraph-1 110012 110013 001114 001105 01001 Eachstationcanhearsomeandnotothers=>Pr(reachable)withassumptionstatic=>notransitionGeneralizethistoann-poseintoak-groupreachabilitygraph- Pr(n)=S(Nr(j)/Nt(j))/kTakeaveragestationspergroup=>work1,23,45(a)(b)(c)HiddenStationModel-DynamicExtendstaticmodelandallowtransitionsbetweenkstates,overnstations?=>adjacencygraphPr(reachable->reachable)=>usecontrolparameter,mPr(hidden->*)=1/l,Pr(reachable->hidden)=(1-m)/(l-1)Balanceequations: Pr(j)+(1–l)Ph(j)=1 (1-m)/(1-l)Pr(j)=(1/l)Ph(j)Solvetoget: Pr(j)=1/(1+l(1–m))12k1234k-stateMarkovchainAdjacency graphOurThroughputModel-SaturationWorstcasethroughputloss=>hiddenstationsalwaystransmitPtr=1;Ps=Nret(1–t)Nre-1Thischangesthroughputto-PsE[P]/(PsTs+PcollTc)IalsochangedTctoincludeACK_Timeout- DIFS+E[P]+SIFS+ACK_..HugedegradationofthroughputforeitherstaticordynamicWLANsWillseesimulationsagreeOurThroughputModel–FiniteLoad(1)Similargroupingintokgroups,butnowwithidenticalloads,liindividuallyandSli=essfulbothfromitsgroupandallothergroups-Further,transmissionprobabilitiesfromkcontendinggroupsconsistingsomestationseachPlugPsandPtrintothroughputequationCanbeusedforbothbasicandRTS/CTSOur