IEEE 802154概要

IEEE802.15.4IntroductionJuly,2006上海顺舟网络科技有限公司•IEEEGroup•802.15.4Overview•PHYLayer•MACLayer上海顺舟网络科技有限公司•IEEE802.15isWorkingGroupforWirelessPersonalAreaNetworks•Focuses:ThedevelopmentofconsensusstandardsforPersonalAreaNetworksorshortdistancewirelessnetworks•Goal:Publishstandards,recommendedpractices,orguidesthathavebroadmarketapplicabilityanddealeffectivelywiththeissuesofcoexistenceandinteroperabilitywithotherwiredandwirelessnetworkingsolutions上海顺舟网络科技有限公司•Group1:–Bluetooth•Group2:–FacilitatecoexistenceofWirelessPersonalAreaNetworks™(802.15)andWirelessLocalAreaNetworks(802.11)•Group3:–Publishanewstandardforhigh-rate(20Mbit/sorgreater)WPANs;–TelecommunicationsandInformationExchangeBetweenSystems-LAN/MAN•Group4:–Zigbee•Group5–determinethenecessarymechanismsthatmustbepresentinthePHYandMAClayersofWPANstoenablemeshnetworking.上海顺舟网络科技有限公司:WirelessMediumAccessControl(MAC)andPhysicalLayer(PHY)SpecificationsforLow-RateWirelessPersonalAreaNetworks(LR-WPANs)上海顺舟网络科技有限公司:•Definethephysicallayer(PHY)andmediumaccesscontrol(MAC)sublayerspecificationsforlowdataratewirelessconnectivitywithfixed,portable,andmovingdeviceswithnobatteryorverylimitedbatteryconsumptionrequirementstypicallyoperatinginthepersonaloperatingspace(POS)of10m.Purpose:•Provideastandardforultra-lowcomplexity,ultra-lowcost,ultra-lowpowerconsumption,andlowdataratewirelessconnectivityamonginexpensivedevices.上海顺舟网络科技有限公司…P1ZigBee802.15.4PHY802.15.4MACZigBeeNWKZDOEP1Hardware上海顺舟网络科技有限公司•ALR-WPANisasimple,low-costcommunicationnetworkthatallowswirelessconnectivityinapplicationswithlimitedpowerandrelaxedthroughputrequirements•ThemainobjectivesofanLR-WPANare:–easeofinstallation–reliabledatatransfer–short-rangeoperation–extremelylowcost–areasonablebatterylife,–asimpleandflexibleprotocol.上海顺舟网络科技有限公司–928MHzISMAmericas40kbps10868.3MHzISMEurope20kbps1BandTypeGeographicCoverageBurstDataRate#ofChannels上海顺舟网络科技有限公司•SomeofthecharacteristicsofanLR-WPANare–Over-the-airdataratesof250kb/s,40kb/s,and20kb/s–Starorpeer-to-peeroperation–Allocated16bitshortor64bitextendedaddresses–Allocationofguaranteedtimeslots(GTSs)–Carriersensemultipleaccesswithcollisionavoidance(CSMA-CA)channelaccess–Fullyacknowledgedprotocolfortransferreliability–Lowpowerconsumption–Energydetection(ED)–Linkqualityindication(LQI)–16channelsinthe2450MHzband,10channelsinthe915MHzband,and1channelinthe868MHzband上海顺舟网络科技有限公司(FFD)•Anytopology•Networkcoordinatorcapable•TalkstoanyotherdeviceReducedFunctionDevice(RFD)•Limitedtobeingleafdevices•Cannotbecomeanetworkcoordinator•Talksonlytoanetworkcoordinator•Verysimpleimplementation上海顺舟网络科技有限公司•Twochannelaccessmechanisms–Beacon-enablednetwork–Non-beaconnetwork•Beacon-enabledNetwork–Fordedicatedbandwidthandlowlatency–Setupbynetworkcoordinatortotransmitinpredeterminedintervals–Beaconframeistransmittedonthefirstslotofeachsuperframe–Beaconsareusedto:synchronizeattacheddevices,identifythePAN(PANID),describethestructureofasuperframe–DeviceswishingtocommunicateduringCAP(ContentionAccessPeriod)betweentwobeaconscompeteusingCSMA-CA–Alltransactionsmustbecompletedbythetimeofthenextnetworkbeacon上海顺舟网络科技有限公司•Non-BeaconMode–Asimple,traditionalmultipleaccesssystemusedinsimplepeerandnear-peernetworks–Thinkofitlikeatwo-wayradionetwork,whereeachclientisautonomousandcaninitiateaconversationatwill,butcouldinterferewithothersunintentionally–However,therecipientmaynothearthecallorthechannelmightalreadybeinuse•BeaconMode–Averypowerfulmechanismforcontrollingpowerconsumptioninextendednetworkslikeclustertreeormesh–Allowsallclientsinalocalpieceofthenetworktheabilitytoknowwhentocommunicatewitheachother–Here,thetwo-wayradionetworkhasacentraldispatcherwhomanagesthechannelandarrangesthecalls•Asyou’llsee,theprimaryvaluewillbeinsystempowerconsumption上海顺舟网络科技有限公司•SuperframestructureƒFordedicatedbandwidthandlowlatencyƒSetupbynetworkcoordinatortotransmitinpredeterminedintervals•15msto245sec•16equaltimeslotsbetweenbeacons−Channelaccessineachtimeslotiscontentionbased;However,networkcoordinatorcandedicateatimeslot−Upto7guaranteedtimeslots(GTS)perbeaconintervalforQualityofService上海顺舟网络科技有限公司•Beacon–Devicelistensforbeacon–Devicesynchronizestosuperframestructure–DevicetransmitsdataframeusingslottedCSMA-CA–Coordinatorsendsoptionalackpacket•Non-Beacon–DevicesendsdataframeusingunslottedCSMACA–Coordinatorsendsoptionalackpacket