简介:Themediumaccesscontrol(MAC)protocolforindoorvisiblelightcommunication(VLC)withenergyharvestingisexploredinthispaper.Theunfairnessofthroughputexistsamongdevicesduetothesignificantdifferenceoftheirenergyharvestingrateswhichchangeswithdistance,acceptanceangleandtheobstructionprobability.Weproposeanenergyharvestingmodel,anewobstructionprobabilitymodelandanenergyadaptivecontentionalgorithmtoovercometheunfairnessproblem.Thisdevicecanadjustitscontentionwindowaccordingtotheenergyharvestingrate.Asaresult,thedevicewithlowerenergyharvestingratecangetshortercontentionwindowtoimproveitstransmissionopportunity.SimulationresultsshowthatourMACprotocolcanachieveahigherdegreeoffairness.
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:互联网技术正在以前所未有的速度与包括能源行业在内的各传统产业相互融合,并已为能源行业的互联网化革命提供了先进的信息通信技术基础。目前,实现能源电力基础设施间的互联互通已经成为亟需突破的瓶颈问题,而泛在绿色社区控制网络协议ISO/IEC/IEEE18880标准的提出为解决这一问题提供了一种行之有效的途径。文章重点介绍了该标准的网络架构及其在能源互联网中的应用。
简介:文章提出了一种基于国密算法安全隧道和IEEE802.1x证书认证技术的变电站安全访问接入点(AccessPoint,AP)设计方法,从信息、通信、安全等维度解决无线接入信息内网的实际问题。通过开发该安全AP,在网络层面采用准入准出控制,基于入网用户的身份有效管控用户的访问权限、流量带宽等,实现移动终端接入的灵活性和安全管控。安全AP能充分满足变电站应用场景下的机器人智能巡检、无线视频监控、PMS移动作业应用等业务的无线通信接入需求。