简介:摘要院随着互联网和移动智能设备的普及,以及无线通信技术的高速发展,802.11凭借着其高速,便捷,低成本的优势被广泛应用于家庭和商业场合。本章主要介绍了802.11技术工作原理和协议连接传输过程,以及对目前应用最广泛的802.11n的特性进行技术性的分析。
简介:Backoffmechanismisakeycomponentofcontention-basedmediumaccesscontrol(MAC)layerprotocol.IthasbeenshownthatthebackoffmechanismofIEEE802.11standardmaybeveryinefficientespeciallywhenthenetworkiscongested.Numbersofmethodshavebeenproposedtotunethecontentionwindow(CW)withtheaimtoachievetheoptimalthroughputinIEEE802.11WLANs.However,themechanismsdonotspecificallyaddresspropersettingsforthevariablepacketlengthinfluenceandCWdivergingproblem.Thispaperproposesanovelfour-wayhandshakingfull-feedbackbackoffalgorithmnamedadoptivecontentionwindowbackoff(ACWB)toovercomethesedrawbacks.Theperformanceoftheproposedalgorithmisinvestigatedthroughanalysisandsimulation.SimulationresultsdemonstratethattheACWBalgorithmprovidesaremarkableperformanceimprovementintermsofshort-termfairness,packetdelayanddelayjitter,whilemaintaininganoptimalthroughputclosetothetheoreticalthroughputlimitoftheIEEE802.11distributedcoordinationfunction(DCF)accessscheme.
简介:WLAN是计算机网络与无线通信技术相结合的产物,它速率高、接入灵活,有着广阔的市场应用前景。本文依据移动WLAN系统的设计思路,提出一个基于IEEE802.11b标准的GSM、3G、WLAN的“三网舍一”的室内覆盖系统设计方案。该方案能解决室内GSM移动手机信号的覆盖问题,同时兼容3G业务覆盖,并接入WLAN系统进行互补,较好的解决了异种移动通信系统相互干扰的问题。总体方案具有较高的性价比和较强的可扩展性。