Spectrum-Sharing-MAC-layer-Protocols：MAC层协议的频谱共享

SpectrumSharing

MAC-layerProtocolsSang-YoonChangECE439Spring2010SpectrumSharing

MAC-layerPr1MotivationBandwidthbecomingscarcerandmorevaluableIncreaseddemandsonwirelessapplicationsUsersdemandhigherperformanceDynamicallyaccessingmultiplechannelscanincreasespectrumefficiencyOurgoalistosupportmultipletransmissionsandincreaseperformancebymitigatinginterferenceMotivationBandwidthbecomings2FCCSpectrumAllocationChartFCCSpectrumAllocationChart3SpectrumUtilizationAsnapshotofspectrumutilizationupto6GHzinanurbanareaatmid-day[1]SpectrumUtilizationAsnapshot4BackgroundCognitiveradioSecondaryusersoperatingonlicensedBandRequiredtodetectprimaryusers’signals(physical-layer)Avoidandyieldthechannelusetoprimaryusers(MAC-layer)Inaddition,coordinationwithothersecondaryusersOtherSpectrumSharingTechniquesUltraWideBand(UWB)CommunicationUnlicensedBand,e.g.,ISMbandBackgroundCognitiveradio5ProjectOverviewRandomaccessprotocolwithoutcoordination[2]Centralizedchannelallocationalgorithm[3]Distributedchannelallocationalgorithm[4],[5]Singleradioperuser[6],[7]Sensingoverhead/limitations[7],[8]Divergingfromtraditionalslottedchannelization[7],[10],[11],[12]Selfishusers[14]MMAC[6],HMAC[7]SWIFT[10]ProjectOverviewRandomaccess6Hidden-TerminalProblemInsingle-channelenvironment,IEEE802.11DCF,busy-toneAssumedsingleradioperuserIEEE802.11DCFinmulti-channelenvironmentCdoesnotheartheCTS(2)fromB,andthuscollisionIfmultipleradiosperuser,DynamicChannelAssignment(DCA)byWu[9]NeedscomplexhardwareHidden-TerminalProblemInsing7MMACProtocolMulti-ChannelMAC(MMAC)bySoandVaidya[6]SingleradioperuserBuildonIEEE802.11PSMprotocol(beaconinterval,ATIM)RequiresglobalsynchronizationInATIMwindow,AgreeonachannelaccordingtoPreferableChannelList(High,Medium,Low)ATIM-REStonotifythechannelreservationMMACProtocolMulti-ChannelMAC8BeaconIntervalBeaconInterval9MMACPerformanceWLAN(above)andmulti-hop(below)environmentAlsoobservedpacketdelayCBRtrafficPacketsize=512BytesBeaconinterval=100msATIMwindowsize=20ms3channelsMMACPerformance10HC-MACProtocolHardware-ConstrainedCognitiveMAC(HC-MAC)

byJiaetal.[7]Singleradio,partialspectrumsensing,spectrumaggregationlimitConstructastoppingproblemtodecidewhetherornottosensefurtherchannelsRobusttomulti-channelhiddenterminalproblemHC-MACProtocolHardware-Constr11HC-MAC:SensingDecisionsB=TransmissionRate,T=PacketDuration,t=SensingTime**HC-MAC:SensingDecisionsB=T12HC-MAC:ControlPacketsContention(C-RTS/C-CTS)CompetingforcommoncontrolchannelaccessSensing(S-RTS/S-CTS)ExchangechannelavailabilityandagreeondatachannelTransmission(T-RTS/T-CTS)NotifyneighboringnodesthecompletionoftransmissionHC-MAC:ControlPacketsContent13SWIFTProtocolSplitWidebandInterfererFriendlyTechnology(SWIFT),Rahul[10]UnlikeUWB,noneedtosacrificetransmissionpower,rateCognitiveaggregationofnon-contiguousfrequencybandAdaptivesensing(probethespectrumandobservereaction)SWIFTProtocolSplitWidebandI14SWIFT:AdaptiveSensing(sec)SWIFT:AdaptiveSensing(sec)15SWIFTBinSync.ProblemSWIFTBinSync.Problem16SWIFT:BinSynchronizationSWIFTusersindependentlydecidewhichbandsthattheycanuse.i)Ifdrasticdisagreementonusablebands,orbootupSendsusablebinsinallfrequencybinsTxerandRxeragreesatleastononeofthebinsii)Iflimiteddisagreement,Stripesdataacrossthepreviouslyagreedbins,buttransmitsonlyinthesubsetthatisstillusableTransformthepotentialdisagreementtobiterrorsErrorcorrectingcodesSWIFT:BinSynchronizationSWI17DiscussionandConclusionSecurityissuesarise,e.g.,Denial-of-Services(primaryuseremulation,jamming,etc.)Analyzedcorrectnessandperformanceofschemesassumingrationalusers(whocarefortheirperformances)Withsmartradiobecomingreality,burgeoninginterestinMACprotocolsthataredesignedformulti-channelenvironmentDiscussionandConclusionSecur18References[1]R.W.Brodersen,A.Wolisz,D.Cabric,andS.M.Mishra,“CORVUS:ACognitiveRadioApproachforUsageofVirtualUnlicensedSpectrum,”2004.[2]S.Huang,X.Liu,andZ.Ding,“OpportunisticSpectrumAccessinCognitiveRadioNetworks,”IEEEInfocom,2008.[3]T.ShuandM.Krunz,“CoordinatedChannelAccessinCognitiveRadioNetworks:AMulti-LevelSpectrumOpportunityPerspective,”IEEEInfocom,2009.[4]J.Zhao,H.Zheng,andG.-H.Yang,“DistributedCoordinationinDynamicSpectrumAllocationNetworks,”IEEEDySPAN,2005.[5]L.Cao,H.Zheng,andG.-H.Yang,“DistributedCoordinationinDynamicSpectrumAllocationNetworks,”IEEECrownCom,2007.[6]J.SoandN.Vaidya,“Multi-ChannelMACforAdHocNetworks:HandlingMulti-ChannelHiddenTerminalsUsingaSingleTransceiver,”ACMMobiHoc,2004.[7]J.Jia,Q.Zhang,andX.Shen,“HC-MAC:AHardware-ConstrainedCognitiveMACforEfficientSpectrumManagement,”IEEEJournalonSelectedAreasinCommunications,vol.26,no.1,pp.106-117,2008.[8]S.Shetty,M.Song,C.Xin,andE.K.Park,“ALearning-BasedMultiuserOpportunisticSpectrumAccessApproachinUnslottedPrimaryNetworks,”IEEEInfocom,2009.[9]S.-L.Wu,C.-Y.Lin,Y.-C.Tseng,andJ.-P.Sheu,“ANewMulti-ChannelMACProtocolwithOn-DemandChannelAs