校園無線網(wǎng)絡(luò)技術(shù)及應(yīng)用發(fā)展(英文版)

28.09.20231校園無線網(wǎng)路技術(shù)與應(yīng)用發(fā)展Sheng-TzongCheng

鄭憲宗stcheng@.tw..tw28.09.2023成大資訊鄭憲宗2Outline無線區(qū)域網(wǎng)路─IEEE802.11無線應(yīng)用通訊協(xié)定─WAP28.09.2023成大資訊鄭憲宗3無線區(qū)域網(wǎng)路通訊協(xié)定WirelessLocalAreaNetwork(IEEE802.11)28.09.2023成大資訊鄭憲宗4無線區(qū)域網(wǎng)路標(biāo)準(zhǔn)-IEEE802.11SpecifiesasingleMediumAccessControl(MAC)sublayerand3PhysicalLayerSpecifications.Stationscanoperateintwoconfigurations:Ad-hocmodeInfrastructuremodeThreePHYspecificationsFrequencyHoppingSpreadSpectrum(FHSS).DirectSequenceSpreadSpectrum(DSSS).InfraredPHY.28.09.2023成大資訊鄭憲宗5IEEE802.11規(guī)範(fàn)IEEEProject802Charter:Local&MetropolitanAreaNetwork1Mbpsto100Mbpsandhigher2lowerlayersof7LayerOSIReferenceModelIEEE802.11WorkingGroupscope:Wirelessconnectivityforfixed,portableandmovingstationswithinalimitedareaAppeartohigherlayer(LLC)thesameasexisting802standardsApplicationLayerNetworkLayerMACPhysicalLayer...LLCIEEE802.11DataLinkLayer28.09.2023成大資訊鄭憲宗61997/6/26通過成為IEEE802系列標(biāo)準(zhǔn)IEEE802.11架構(gòu)MediaAccessControlLogicalLinkControlInfraredPhysicalLayerFHSSPhysicalLayerDSSSPhysicalLayer28.09.2023成大資訊鄭憲宗7AdHoc網(wǎng)路OneBasicServiceSetDirectedConnectionLimitedCoverageArea28.09.2023成大資訊鄭憲宗8APBSSInfrastructure網(wǎng)路APBasicServiceSetExistingWiredLANDistributionSystemOtherLANsExtendServiceSet28.09.2023成大資訊鄭憲宗9Infrastructure網(wǎng)路(cont.)AccessPointandMobileStationDistributedSystemInterconnectMultipleCellsviaAccessPointstoformasinglenetworkExtendsWirelessCoverageAreaMultipleBasicServiceSetsconnectedtogetherformanExtendedServiceSetAllowMobileStationtoaccessfixedresourceSupportRoamingforMobileStationsviaAccessPointPointCoordinationFunction,PowerManagement,TimeSynchronizationsupportthroughAccessPoint28.09.2023成大資訊鄭憲宗10IEEE802.11ServicesProvidesserviceswiththefollowingfunctionality:roamingwithinaESS,multipledataratesinBSSsandPowerManagement.TheMACprotocolisCarrierSenseMultipleAccesswithCollisionAvoidance(CSMA/CA)MACservicesAssociationserviceAuthenticationserviceDistributionserviceIntegrationserviceDeauthentication/Deassociationservice28.09.2023成大資訊鄭憲宗11SpreadSpectrumTechnologyDSSS（DirectSequenceSpreadSpectrum）11channelsPN-code長度為11-bit展頻寬度為11MHzFHSS（FrequencyHoppingSpreadSpectrum）78hopsequences頻帶範(fàn)圍為1MHz，跳頻的頻率為每秒2.5次InfraredRay發(fā)展趨勢：DHSS往高速無線區(qū)域網(wǎng)路系統(tǒng)發(fā)展，適合辦公室環(huán)境使用；FHSS會往低價網(wǎng)路應(yīng)用發(fā)展，提供SOHO及家庭應(yīng)用、或周邊設(shè)備之無線網(wǎng)路連結(jié)。28.09.2023成大資訊鄭憲宗12直接序列展頻（DSSS）28.09.2023成大資訊鄭憲宗13跳頻展頻（FHSS）28.09.2023成大資訊鄭憲宗14IEEE802.11TGaTheTGaisworkingonthehighdata-rateextensioninthe5GHzband,project802.11a,wasabletoproduceanewdraftstandardthathasthesupportofatleast80%ofthemembers.TGaislookingatacandidateforworldwidestandardization!28.09.2023成大資訊鄭憲宗15IEEE802.11TGa(cont.)ThespecificationsofthePhysicalLayerencompassdataratesfrom6Mbit/supto54Mbit/s,with20MHzspacingbetweenadjacentchannels.Allimplementationsarerequiredtosupport6,12and24Mbit/s.Optionalextensionsarefor9,18,36,48and54Mbit/s.Themulti-ratemechanismoftheMACprotocolensuresthatalldevicescommunicatewitheachotheratthebestdatarateinthepresentchannel.28.09.2023成大資訊鄭憲宗16IEEE802.11TGbTheTGbisworkingontheextensionofthe1and2Mbit/sdataratesinthe2.45GHzbandwith5.5and11Mbit/shasreachedatechnicalcompromisesolutiontoimprovetheco-existenceandinteroperabilitycharacteristicsbetweenoptions.Themulti-ratemechanismwarrantsthatthe11Mbit/soperationcanswitchbackto5.5Mbit/s.Stationsthatareevenfurthercouldswitchbacktothe2and1Mbit/scapabilitiesoftheDSSSmodulation.28.09.2023成大資訊鄭憲宗17CSMA/CD(LAN)Senddataifthemediumissensed“idle”Ifcollideswithotherhost(s), thenbackoffforarandomnumberoftimesRe-senddatalater28.09.2023成大資訊鄭憲宗18HiddenTerminalProblemBACdatadata28.09.2023成大資訊鄭憲宗19SolutiontoHTPBACRequestGrant28.09.2023成大資訊鄭憲宗20DetectionofCollisionBACRequestRequest28.09.2023成大資訊鄭憲宗21BACRequestAisGrantAisGrantDCollisionAvoidance28.09.2023成大資訊鄭憲宗22RTS/CTS/data/ACKandNAVsetting28.09.2023成大資訊鄭憲宗23SomeIFSrelationshipsandbasicaccessmethod28.09.2023成大資訊鄭憲宗24RandombackofftimeBackofftime=INT(CW*Random())*aSlotTimeINT(x):小於或等於x的最大整數(shù)CW(contentionwindowparameter):介於CWmin和Cwmax間的整數(shù),CW依序遞增的順序為(7,15,31,63,127,255,255,255……)Random():介於0到1間的實數(shù)aSlotTime:傳送器開啟延遲+媒介傳遞延遲+媒介忙碌偵測反應(yīng)時間28.09.2023成大資訊鄭憲宗25AnexampleofexponentialincreaseofCW28.09.2023成大資訊鄭憲宗26Backoffprocedure28.09.2023成大資訊鄭憲宗27Transmissionofamulti-fragmentMPDUusingSIFS28.09.2023成大資訊鄭憲宗28RTS/CTSwithfragmentedMSDU28.09.2023成大資訊鄭憲宗29RTS/CTSwithtransmitterpriorityandmissedacknowledgment28.09.2023成大資訊鄭憲宗30Directdata/ACKMPDU28.09.2023成大資訊鄭憲宗31無線區(qū)域網(wǎng)路軟體技術(shù)架構(gòu)WLANPlatformEmbeddedControlSoftwareWLANManagementUtilityNetworkApplicationsDSSSFHSSMediaAccessControlNetworkDriver(NDIS)SocketInterfaceMobileIPSNMPAgentSecurityDistributedServiceE-MailFileTransferRemoteAccessMobileDataDECTU-NIIorISMbandETSI28.09.2023成大資訊鄭憲宗32無線應(yīng)用通訊協(xié)定WirelessApplicationProtocol(WAP)28.09.2023成大資訊鄭憲宗33無線上網(wǎng)趨勢日本NTT的DoCoMo

於2/1999推出無線上網(wǎng)服務(wù)，一年內(nèi)累積3百萬用戶，每週增加10萬人WAPForum於1997年成立，至1999年12月全世界有200家無線通訊事業(yè)成為會員(95%市場之相關(guān)業(yè)者投入)1999年，WAP是手機使用者最熱門話題之一28.09.2023成大資訊鄭憲宗34無線上網(wǎng)趨勢(續(xù))1999年在臺灣銷售180萬隻手機前兩大廠─Motorola於2000上半年WAP手機佔40%，下半年100%投入；Nokia則佔30%。國內(nèi)新上市的手機六到七成內(nèi)建WAP功能臺灣已超過1000萬人有行動手機，而PC上網(wǎng)人數(shù)約3至4百萬語音：數(shù)據(jù)─95%:5%(2000);40%:60%(2005)28.09.2023成大資訊鄭憲宗35全球無線通訊用戶成長28.09.2023成大資訊鄭憲宗36預(yù)估未來WAP手機的佔有率28.09.2023成大資訊鄭憲宗3728.09.2023成大資訊鄭憲宗3828.09.2023成大資訊鄭憲宗39手持型元件之延革28.09.2023成大資訊鄭憲宗4028.09.2023成大資訊鄭憲宗41bringtheinternetcontentandadvancedservicesto後PC時代之userscreateaglobalwirelessprotocoltoworkacrossdifferingwirelessnetworktechnologies

enableapplicationstoscaleacrossavarietyoftransportoptionsanddevicetypesWhat’sWAPfor?28.09.2023成大資訊鄭憲宗42WhatisdefinedinWAP?Micro-BrowserScriptingtoenhanceMScapabilitiesWTA/WTAIfortelephonefunctionality(e.g.callchains)ContentFormatsbusinesscard(vCard)calendarevent(vCalendar)LayeredTelecommunicationStack28.09.2023成大資訊鄭憲宗43Comparison28.09.2023成大資訊鄭憲宗4428.09.2023成大資訊鄭憲宗45GoalsforWTP(WAPv1.1)acommoninterfacetophysicaltransportmechanismsprovideaport-basedabstractinterfacetoupperlayerprotocolsallowapplicationsdesignedindependentfromspecifictransportsextensibletoavarietyofdigitalwirelessnetworksandfuturetransportoptions28.09.2023成大資訊鄭憲宗46GoalsforWTP(cont.)supportsconnection-oriented,transaction,anddatagrammodesoptimizefornarrowtomediumbandwidthchannelstobecapableofimplementationinalowmemoryfootprint,suitableforstandardorlow-IQhandsets28.09.2023成大資訊鄭憲宗47RequirementsforWTPWTP/Cprovidesareliableconnection-orientedservicetotheupperlayerWTP/Tprovidesareliabletransaction-orientedservicesuitableforwebbrowsingWTP/Dprovidesadatagramservicelightweight:implementablein<=10Kb(lowmemory/computationalneeds)28.09.2023成大資訊鄭憲宗48WTP/Dfeatures

(WDPinWAPv1.2)WTP/D(Datagram)providesaconnection-less,unreliabledatagramserviceWTP/DisreplacedbyUDPwhenusedoveranIPnetworklayer.usestheServicePrimitiveT-UnitData.req.ind28.09.2023成大資訊鄭憲宗49WAPv1.2WirelessBearers:SMSUSSDCSDIS-136CDMAIDENCDPDPDC-PGPRSWirelessApplicationEnvironment(WAE)WirelessSessionProtocol(WSP)WirelessTransactionProtocol(WTP)WirelessTransportLayerSecurity(WTLS)Datagrams(UDP/IP)Datagrams(WDP)OtherServicesandApplicationsWirelessBearers:SMSUSSDCSDIS-136CDMAIDENCDPDPDC-PGPRSWirelessApplicationEnvironment(WAE)WirelessSessionProtocol(WSP)WirelessTransactionProtocol(WTP)WirelessTransportLayerSecurity(WTLS)Datagrams(UDP/IP)Datagrams(WDP)OtherServicesandApplications28.09.2023成大資訊鄭憲宗50WTP/Tfeatures

(WTPinWAPv1.2)

WTP/T(Transaction)providesreliabledatatransferbasedonrequest/replyparadigmnoexplicitconnectionsetuporteardowndatacarriedinfirstpacketofprotocolexchangeseekstoreduce3-wayhandshakeoninitialrequest28.09.2023成大資訊鄭憲宗51WTP/Tfeatures(cont.)

supportsretransmissionoflostpacketsselective-retransmissionsegmentation/re-assemblyportnumberaddressing(specifictoWTP/T)flowcontrolmessageoriented(notstream)supportsanAbortfunctionforoutstandingrequests28.09.2023成大資訊鄭憲宗52WirelessSessionProtocol

WSP/BprovidesupperlayerswithsessionservicesandmanagementWSP/BProvidessemanticsandmechanismsbasedonHTTP1.1WSPprovidesmeansto:establishareliablesessionfromclienttoserveragreeoncommonlevelofprotocolfunctionalitybycapabilitynegotiationcompactencodingsuspendandresume28.09.2023成大資訊鄭憲宗53WSPfeaturesHTTP1.1functionalityExchangeofclientandserversessionheadersInterruptmechanismfortransactionsinprocessContentPushfromservertoclientNegotiationformultiple,simultaneousasynchronoustransactions28.09.2023成大資訊鄭憲宗54WTLSRecordProtocol

4recordprotocolclients:ThehandshakeprotocolThechangecipherspecprotocolThealertprotocolTheapplicationdataprotocolWTLSconnectionstate:theoperatingenvironmentforrecordprotocolcompression/encryptionalgorithmMACalgorithm--keys28.09.2023成大資訊鄭憲宗55RecordProtocolUsage

HandshakeprotocolNegotiatesecureattributesofasecuresessionauthentication,securityparametersettingsChangecipherspecprotocolSignaltransitionsincipheringstrategiessentbeforeverifyingfinishedmessageAlertprotocolconveytheseverityofthemessageandadescriptionofthealert28.09.2023成大資訊鄭憲宗56WirelessApplicationEnvironment

(WAE)

AnInternet(.)programmingmodel

Vendor-controlledMMIInitialfocusonphonesSlowbearersSmallmemoryLimitedCPUSmallscreenLimitedinputmodel28.09.2023成大資訊鄭憲宗57WAEComponentsArchitecture–Applicationmodel–Browser,Gateway,ContentServerWML(WirelessMarkupLanguage)–DisplaylanguageWMLScript–ScriptinglanguageContentFormats–Dataexchange28.09.2023成大資訊鄭憲宗58WAEIn-DeviceArchitecture28.09.2023成大資訊鄭憲宗59WML

Tag-basedbrowsinglanguage:Screenmanagement(text,images)Datainput(text,selectionlists,etc.)Hyperlinks&navigationsupportSyntax:W3CXML(SGMLderivative)InheritstechnologyfromHDMLandHTML28.09.2023成大資訊鄭憲宗60WML(cont.)

CardmetaphorUserinteractionsaresplitintocardsNavigationoccursbetweencardsStatemanagementandvariablesReducenetworktrafficResultsinbettercachingExplicitinter-cardnavigationmodelHyperlinksUIEventhandlingHistory28.09.2023成大資訊鄭憲宗61WMLExample

28.09.2023成大資訊鄭憲宗62WMLScript

Scriptinglanguage:Procedurallogic,loops,conditionals,etc.Optimizedforsmall-memory,small-cpudevicesDerivedfromJavaScript?IntegratedwithWMLPowerful