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ID:59440819
大小:852.00 KB
页数:53页
时间:2020-09-18
《无线网路的概观与80211无线区域网路(Overview)ppt课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、IEEE802.11OverviewRong-HongJanDeptofComputerandInformationScienceNationalChiaoTungUniversity802.11Technologies:Past,PresentandFutureApprovedandnear-term802.11LetterStandardsFaster:Standards-basedWi-Finowdeliversdataratesupto54MbpstoWi-Ficlients.(11a,11g)Better-performing:Theneedforabetter-performin
2、gMAChasbeendrivenbydemandingapplicationsuchasvoiceandvideo.QualityofServiceenhancementshavemodifiedtheMACtoprovideadmissioncontrolandprioritizedchannelaccess.(11e)3Moresecure:Securityenhancementshavebeendevelopedtoaddressaccesscontrolandauthenticationanddataprivacyandintegrity,drivenbythemarketrequi
3、rementforenterprise-levelsecurityinwirelessLANs.(11i)Broaderapplicability:Regulatoryenhancementsthatbroadentheapplicabilityof802.11tootherfrequenciessuchas4.9GHzinJapanandotherregulatorydomains.(11j)4PhysicalLayerenhancements11a,11b,11gQualityofService(QoS)enhancements11eSecurityenhancements11iWPARe
4、gulatoryenhancements11d11h5Future802.11Standards802.11jThe802.11jTaskGroupisworkingonJapaneseregulatoryextensionstoallowforoperationinthe4.9GHzand5GHzbandsinJapan.Thisisexpectedtobeapprovedin2005.802.11k802.11kisfocusedonstandardizingtheradiomeasurementsthatwillallowuniformmeasurementofradioinformat
5、ionacrossdifferentmanufacturerplatforms.6Byhavingstandardized,repeatablemeasurements,systemdesignerscanutilizeradioenvironmentinformationtomakebetterdecisionsastofrequencyuse,transmitpowerlevels,etc.802.11nThe802.11nTaskGroupisfocusingoncreatingastandardtofurtherincreasethenetthroughputofwirelessnet
6、works.Thegoalistoachievegreaterthan150Mbpsusablethroughputoveran802.11.7BothphysicalandMAClayerchangesarebeingconsidered,butbackwardcompatibilityisrequired.802.11rThe802.11rTaskGroupisworkingonreducingthehandofflatencywhenclientdevicestransitionbetweenaccesspointsorcellsinanESS.Thisstandardwillfacil
7、itatethedeploymentofSIP-basedVoiceoverWi-Fi(VoWi-Fi)portablephones.8802.11sThe802.11sTaskGroupisworkingonaninfrastructuremeshstandardtoallow802.11accesspointsorcellsfrommultiplemanufacturerstoself-con
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