22090107000000cpeautomatonsection.docx

22090107000000cpeautomatonsection.docx

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22090107000000cpeautomatonsection

IEEEP802.22

WirelessRANs

CPESpectrumSensingAutomaton

Date:

2009-05-14

Author（s）:

Name

Company

Address

Phone

email

GeraldChouinard

CRC

3701CarlingAve.Ottawa,OntarioCanadaK2H8S2

613-998-2500

gerald.chouinard@crc.ca

Abstract

Thisdocumentproposesanewversionofsection9.3forthe802.22Draftasaresponsetocomments#768to#789andcomments#962to#973.StateofthedocumentisasofMay14.Blockdiagramswereapprovedas“logicaldepictionofthebehaviourofthespectrumautomatonbutnotanimplementationexample”.Itwasagreedunanimouslythatthesediagramsshouldbebroughttothenormativesection9.3.Furtherrefinementtothetexttoreflectthediagramswillbedonebytheeditor.

Notice:

ThisdocumenthasbeenpreparedtoassistIEEE802.22.Itisofferedasabasisfordiscussionandisnotbindingonthecontributingindividual（s）ororganization（s）.Thematerialinthisdocumentissubjecttochangeinformandcontentafterfurtherstudy.Thecontributor（s）reserve（s）therighttoadd,amendorwithdrawmaterialcontainedherein.

Release:

Thecontributorgrantsafree,irrevocablelicensetotheIEEEtoincorporatematerialcontainedinthiscontribution,andanymodificationsthereof,inthecreationofanIEEEStandardspublication;tocopyrightintheIEEE’snameanyIEEEStandardspublicationeventhoughitmayincludeportionsofthiscontribution;andattheIEEE’ssolediscretiontopermitotherstoreproduceinwholeorinparttheresultingIEEEStandardspublication.ThecontributoralsoacknowledgesandacceptsthatthiscontributionmaybemadepublicbyIEEE802.22.

PatentPolicyandProcedures:

ThecontributorisfamiliarwiththeIEEE802PatentPolicyandProcedures

//standards.ieee.org/guides/bylaws/sb-bylaws.pdf>,includingthestatement"IEEEstandardsmayincludetheknownuseofpatent（s）,includingpatentapplications,providedtheIEEEreceivesassurancefromthepatentholderorapplicantwithrespecttopatentsessentialforcompliancewithbothmandatoryandoptionalportionsofthestandard."EarlydisclosuretotheWorkingGroupofpatentinformationthatmightberelevanttothestandardisessentialtoreducethepossibilityfordelaysinthedevelopmentprocessandincreasethelikelihoodthatthedraftpublicationwillbeapprovedforpublication.PleasenotifytheChairasearlyaspossible,inwrittenorelectronicform,ifpatentedtechnology（ortechnologyunderpatentapplication）mightbeincorporatedintoadraftstandardbeingdevelopedwithintheIEEE802.22WorkingGroup.Ifyouhavequestions,contacttheIEEEPatentCommitteeAdministratorat.

CPEspectrumsensingautomaton

TheBSnormallycontrolsthesensingbehavioroftheCPE.HowevertheCPEshallcontrolitssensingbehaviorlocallyunderthefollowingconditions:

1.attheinitialturn-onoftheCPEbeforeassociationisestablishedwiththebasestation;

2.whentheCPElosescontactwithitsbasestation;and

3.duringidletimewhenthebasestationhasnotattributedanyspecifictasktoeithertheCPEsensingsignalpathortheWRANsignalpath,orboth.

ThefunctionalityoftheCPElocalautonomousspectrumsensingforthesethreespecificcasesiscoveredinthefollowingsub-clauses.Amoredetaileddescriptionusinganexampleofapossibleimplementationisgivenin0.

9.3.1Initialturn-on

ThefunctionalityoftheCPElocalautonomousspectrumsensingprocess,whentheCPEisinitiallyswitchedonbeforeassociationwiththebasestation,issummarizedbelowandadescriptionofanexampleofimplementationisgiveninAnnexD.Atinitialturn-onandself-test,theCPEshallsweepaspecificchannel,aspecifiedrangeofchannelsorallthechannelsthatarelikelytobeimpactedbytheCPEoperatingonagivenchanneldependingontheindicationsforthehigherlayers.IfalltheTVchannelsofarangeofoperationneedtobesensedoneadditionalchannelatbothendsoftherangeshallbesensedtocovertheadjacentchannelcaseunlessitgoesbeyondtheextentoftherelevantTVband.

Foreachchannel,anRSSImeasurementshallbeperformedontheWRANsignalpathandattemptshallbemadetocaptureaWRANsuperframeheaderoraCBPburst.IfanSCHiscapturedandtheleveloftheRFsignalissufficientlyhigh,theWRANsignalpathshallattempttoacquiretheframeheader,thebroadcastPDU’ssentbytheBStoadvertisetheWRANserviceforCPEinitializationandthemanagementpacketprovidingthechanneloccupancyfromthebasestation;i.e.,theCHO-UPDMACmessage.IfanSCHcanbeacquiredbutthesignallevelisinsufficientoraCBPburstcanbecaptured,thepresenceofaWRANsignalshallberecordedalongwiththechannelnumberandthemeasuredRSSI.IfanSCHoraCBPburstcannotbedetected,thesensingpathRSSIwillbeevaluatedwhethertheleveloftheRFsignalissufficienttocarryoutafastsignalclassification.

ForthoseTVchannelswheretheRFenergyisfoundtobeinsufficienttoallowforfastsignalclassificationorevenprovideforareliableRSSImeasurement,finesensingshallbeappliedtodeterminethepresenceofbroadcastincumbentsandtheirsignaltype.TheresultofthemeasurementandthesignalclassificationshallbestoredlocallysothatitcanlaterbesenttothebasestationwhenassociationisestablishedorlateronuponrequestfromtheBS.

Thechannelshallthenbeincrementedtorepeattheaboveinitialsensing.Theorderinwhichthechannelsaretobesensedwillbeimplementationdependent.NotethattheinformationacquiredfromthelocalWRANbasestationsthroughtheCHO-UPDMACmessageduringinitializationcouldbeusedtoskipthenon-availablechannels.Itcouldalsobeusedtoskipthesignalclassificationandlowlevelsensingonchannelsbelongingtothe“protected”settosavetimealthough,sincetimeislesscriticalatinitialization,itmaybeusefulthattheCPEconfirmsthattheincumbentsindicatedbytheBSreallyexistinthese‘occupied’channelsatitslocation.

OncealltheTVchannelstobescannedhavebeensensed,theinformationonthelocalWRANchanneloccupancythatwouldnotcreateinterferencetolocalincumbentsonchannelsNandN+/-1shallbemadeavailabletothehigherlayersattheCPE.IfthereisnoWRANchannelthatcanbeused,theCPEinitializationshallbeaborted.DependingontheCPEimplementation,theinformationobtainedfromthevariousWRANbasestationsmaybepresentedtothelocalinterfaceoftheCPEsothatitcouldultimatelybedisplayedonthescreenoftheuserterminaltoallowforaninformedselectionamongavailablelocalWRANnetworks（similartotheAccessPointselectioninWi-Fi）.LocalalgorithmscouldalsobeimplementedintheCPEtoautomatetheprocessforchoosingtheWRANnetwork.

Asecondroundofspectrumsensingshallthentakeplaceontheselectedchannel（N0）anditsadjacentchannels（N0+/-1）.Since,bydefinition,aWRANserviceispresentontheselectedchannel,theWRANsignalpathshallacquiretheSCHortheCBPbursttodeterminethetimingofthequietperiodsinthischannel.Low-powersignalsensingandsignalclassificationshallthenbecarriedoutinchannelN0bythesensingpathduringthequietperiodstoverifythepresenceandattemptidentificationofincumbentserviceunderneaththeWRANservice.Thefindingsshallberecordedlocally.

ThesensingprocessshallthenmovetosensethetwoadjacentchannelsduringthequietperiodsbymeasuringtheRSSIand,dependingonwhetherthemeasuredsignallevelishighorlow,sensethepresenceofanincumbentsignalandclassifyitstypeusingafastalgorithmoralow-levelsensingscheme.Ifthechannelbelongstothe“protected”setassignaledbytheCHO-UPDmessage,thesignalclassificationcouldbeskippedsinceitisalreadyknownbythebasestation.Otherwise,thefindingsshallberecordedlocallyandifincumbentsarefoundinthesechannels,theselectedchannelshallbeeliminatedfromthelistofavailableWRANservicesandtheupdatedlistwillbepresentedtothehigherlayersattheCPEfortheselectionofanotherWRANservice.IfnomoreWRANserviceexists,theCPEinitializationshallbeaborted.Ifnoincumbentispresentinthethreechannelssensed,theCPEinitializationprocessshallcontinueasdescribedinsection6.16.2.

Iftheauthorizationisrefusedbythecurrentlyselectedbasestation,anewshortenedlistofavailableWRANservicesshallbepresentedtothehigherlayersattheCPEforanewchannelselectiontobemade.Then,thenextroundofsensingprocessshallberepeatedwiththealignmentoftheazimuthoftheantennatowardthenewlyselectedWRANbasestationandthesensingofthenewlyselectedchannel（N0）anditsadjacentchannels（N0+/-1）asdescribedabove.Uponsuccessfulsensingresults,theCPEassociationprocesswillcontinueasdescribedinsectionError!

Referencesourcenotfound..

9.3.2Lossofcontactwiththebasestation

IftheCPEloosescontactwithitsbasestation,theCPEautomatonlocalintelligenceshallmakesurethatareasonablenumberofattemptsaremadetore-connectwiththebasestation,whileavoidinganypotentialinterferencetolicensedincumbents.ThefunctionalityoftheCPElocalautomatonissummarizedbelowforthelossofcontactwiththebasestation.

TheCPEshallfirstidentifywhetherornotaWRANsignalisstillpresentontheselectedchannelbytryingtocapturetheSCH.Ifsuccessfulwithin2seconds,attemptstore-associateshallbemadethroughtheBWRequestopportunisticburstoruponspecificinvitationbytheBS.Ifthisdoesnotwork,there-associationshallstartfromanearlierstagewiththeCDMArangingburst.Ifr