Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during th...Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during the operational cycle,which results in the packet delivery latency increased significantly on the multiple hops path.To reduce the packet delivery latency on multi-hop path and energy waste of the sender's idle listening,a new low latency routing-enhanced asynchronous duty-cycle MAC protocol was presented,called REA-MAC.In REA-MAC,each sensor node decided when it waked up to send the beacon based on cross-layer routing information.Furthermore,the sender adaptively waked up based on the relationship between the transmission request time and the wakeup time of its next hop node.The simulation results show that REA-MAC reduces delivery latency by 60% compared to RI-MAC and reduces 8.77% power consumption on average.Under heavy traffic,REA-MAC's throughput is 1.48 times of RI-MAC's.展开更多
基于OFDMA-WLAN系统提出了一种改进的上行MAC协议,用以提高IEEE802.11无线局域网(Wireless Local Area Network,WLAN)在大量站点(stations,STAs)存在时的信道利用率和吞吐量。在OFDMA-WLAN系统存在多个子信道时,该协议使多个STA同时在...基于OFDMA-WLAN系统提出了一种改进的上行MAC协议,用以提高IEEE802.11无线局域网(Wireless Local Area Network,WLAN)在大量站点(stations,STAs)存在时的信道利用率和吞吐量。在OFDMA-WLAN系统存在多个子信道时,该协议使多个STA同时在时域与频域上按照CSMA/CA方式发送信道接入的请求帧,在不需要额外增加信道与射频的基础上,解决了随机接入带来的静默问题。数值分析结果表明,与现有的基于OFDMA的上行MAC协议FICA相比,本协议较好地提高了系统的信道利用率和吞吐量。展开更多
随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)...随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)是下一代WLAN的重要特性,然而已有的关于下一代WLAN的多址接入协议研究或者较少关注QoS保障,或者对于公平性保障较差。文章提出了一种面向QoS的下一代WLAN OFDMA多址接入协议:QoS-OFDMA。该协议引入了2次OFDMA并行随机接入的思想,第1次随机接入不区分业务优先级,从而保障了公平性;进一步允许第1次随机接入失败的高优先级用户,在分配剩余的可用子信道上,进行第2次随机接入,从而保障了高优先级业务的QoS。仿真结果表明,与RA-OFDMA协议和OMAX协议相比,QoS-OFDMA高优先级业务吞吐量分别提升了22.05%和89.6%,同时很好地保障了低优先级业务公平性。展开更多
针对现有能够应用于太赫兹超高速无线网络的能量和频谱感知的媒介接入控制(energy and spectrum-aware media access control,ES-MAC)及IEEE802.15.3c协议存在的时隙申请量未及时更新、超帧结构不合理及分配时隙时未合并同一对节点之间...针对现有能够应用于太赫兹超高速无线网络的能量和频谱感知的媒介接入控制(energy and spectrum-aware media access control,ES-MAC)及IEEE802.15.3c协议存在的时隙申请量未及时更新、超帧结构不合理及分配时隙时未合并同一对节点之间的时隙请求等问题,提出了一种高吞吐量低时延MAC(high throughput low delay MAC,HLMAC)协议。通过设计一种新的超帧结构,使节点及时得到时隙分配信息,大大降低数据接入时延;通过更新时隙请求量和合并同一对节点的时隙请求,增加了数据发送量,提高了网络吞吐量。理论分析表明了HLMAC协议的有效性,仿真结果显示它比ES-MAC协议增加了65.7%的网络吞吐量,同时降低了30%的接入时延。展开更多
基金Projects(61103011,61170261) supported by the National Natural Science Foundation of China
文摘Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during the operational cycle,which results in the packet delivery latency increased significantly on the multiple hops path.To reduce the packet delivery latency on multi-hop path and energy waste of the sender's idle listening,a new low latency routing-enhanced asynchronous duty-cycle MAC protocol was presented,called REA-MAC.In REA-MAC,each sensor node decided when it waked up to send the beacon based on cross-layer routing information.Furthermore,the sender adaptively waked up based on the relationship between the transmission request time and the wakeup time of its next hop node.The simulation results show that REA-MAC reduces delivery latency by 60% compared to RI-MAC and reduces 8.77% power consumption on average.Under heavy traffic,REA-MAC's throughput is 1.48 times of RI-MAC's.
文摘基于OFDMA-WLAN系统提出了一种改进的上行MAC协议,用以提高IEEE802.11无线局域网(Wireless Local Area Network,WLAN)在大量站点(stations,STAs)存在时的信道利用率和吞吐量。在OFDMA-WLAN系统存在多个子信道时,该协议使多个STA同时在时域与频域上按照CSMA/CA方式发送信道接入的请求帧,在不需要额外增加信道与射频的基础上,解决了随机接入带来的静默问题。数值分析结果表明,与现有的基于OFDMA的上行MAC协议FICA相比,本协议较好地提高了系统的信道利用率和吞吐量。
文摘随着无线服务的日趋多样化和业务量的爆炸式增长,服务质量(quality of service,QoS)的保障是下一代无线局域网(wireless local area network,WLAN)的重要目标之一。正交频分多址(orthogonal frequency division multiple access,OFDMA)是下一代WLAN的重要特性,然而已有的关于下一代WLAN的多址接入协议研究或者较少关注QoS保障,或者对于公平性保障较差。文章提出了一种面向QoS的下一代WLAN OFDMA多址接入协议:QoS-OFDMA。该协议引入了2次OFDMA并行随机接入的思想,第1次随机接入不区分业务优先级,从而保障了公平性;进一步允许第1次随机接入失败的高优先级用户,在分配剩余的可用子信道上,进行第2次随机接入,从而保障了高优先级业务的QoS。仿真结果表明,与RA-OFDMA协议和OMAX协议相比,QoS-OFDMA高优先级业务吞吐量分别提升了22.05%和89.6%,同时很好地保障了低优先级业务公平性。
基金Supported by the National High-Tech Research and Development Plan of China under Grant No.2005AA121570(国家高技术研究发展计划(863))the National Basic Research Program of China under Grant No.2003CB314802(国家重点基础研究发展计划(973))
文摘针对现有能够应用于太赫兹超高速无线网络的能量和频谱感知的媒介接入控制(energy and spectrum-aware media access control,ES-MAC)及IEEE802.15.3c协议存在的时隙申请量未及时更新、超帧结构不合理及分配时隙时未合并同一对节点之间的时隙请求等问题,提出了一种高吞吐量低时延MAC(high throughput low delay MAC,HLMAC)协议。通过设计一种新的超帧结构,使节点及时得到时隙分配信息,大大降低数据接入时延;通过更新时隙请求量和合并同一对节点的时隙请求,增加了数据发送量,提高了网络吞吐量。理论分析表明了HLMAC协议的有效性,仿真结果显示它比ES-MAC协议增加了65.7%的网络吞吐量,同时降低了30%的接入时延。
基金Supported by the Program for New Century Excellent Talents in University of China under Grant No.NCET-05-0657(新世纪优秀人才支持计划)the Foundation for Distinguished Young Scientists of Hubei Province of China under Grant No.2006ABB028(湖北省青年杰出人才基金)
