To the existing spectrum sharing schemes in wireless-powered cognitive wireless sensor networks,the protocols are limited to either separate the primary and the secondary transmission or allow the secondary user to tr...To the existing spectrum sharing schemes in wireless-powered cognitive wireless sensor networks,the protocols are limited to either separate the primary and the secondary transmission or allow the secondary user to transmit signals in a time slot when it forwards the primary signal.In order to address this limitation,a novel cooperative spectrum sharing scheme is proposed,where the secondary transmission is multiplexed with both the primary transmission and the relay transmission.Specifically,the process of transmission is on a three-phase time-switching relaying basis.In the first phase,a cognitive sensor node SU1 scavenges energy from the primary transmission.In the second phase,another sensor node SU2 and primary transmitter simultaneously transmit signals to the SU1.In the third phase,the node SU1 can assist the primary transmission to acquire the opportunity of spectrum sharing.Joint decoding and interference cancellation technique is adopted at the receivers to retrieve the desired signals.We further derive the closed-form expressions for the outage probabilities of both the primary and secondary systems.Moreover,we address optimization of energy harvesting duration and power allocation coefficient strategy under performance criteria.An effective algorithm is then presented to solve the optimization problem.Simulation results demonstrate that with the optimized solutions,the sensor nodes with the proposed cooperative spectrum sharing scheme can utilize the spectrum in a more efficient manner without deteriorating the performance of the primary transmission,as compared with the existing one-directional scheme in the literature.展开更多
为解决ZigBee Cluster-Tree路由算法路径选择不优的问题,提出了一种能量感知的ZigBee树型路由EZTR(Energy-Aware ZigBee tree routing)算法.该算法利用每个节点感知的地址信息,按照ZigBee网络树型结构计算下一跳邻居节点到目的节点之间...为解决ZigBee Cluster-Tree路由算法路径选择不优的问题,提出了一种能量感知的ZigBee树型路由EZTR(Energy-Aware ZigBee tree routing)算法.该算法利用每个节点感知的地址信息,按照ZigBee网络树型结构计算下一跳邻居节点到目的节点之间的跳数可避免网络的环路效应,通过引入认知概念,在跳数集合中选出最短路径以降低跳数.在ZigBee网络节点能量的感知过程中,当所选路径存在低能量节点时,及时启用备用节点,从而避免节点因能量过度消耗成为失效节点.NS2(Network simulator version 2)仿真实验表明,EZTR算法可提高网络分组递交率,有效减少节点转发跳数和平均网络延时,减小网络整体能耗,为提高网络的实时性和延长网络生命周期提供理论支持.展开更多
基金Project (61201086) supported by the National Natural Science Foundation of ChinaProject (201506375060) supported by the China Scholarship Council+2 种基金Project (2013B090500007) supported by Guangdong Provincial Science and Technology Project,ChinaProject (2014509102205) supported by the Dongguan Municipal Project on the Integration of Industry,Education and Research,ChinaProject (2017GK5019) supported by 2017 Hunan-Tech&Innovation Investment Project,China
文摘To the existing spectrum sharing schemes in wireless-powered cognitive wireless sensor networks,the protocols are limited to either separate the primary and the secondary transmission or allow the secondary user to transmit signals in a time slot when it forwards the primary signal.In order to address this limitation,a novel cooperative spectrum sharing scheme is proposed,where the secondary transmission is multiplexed with both the primary transmission and the relay transmission.Specifically,the process of transmission is on a three-phase time-switching relaying basis.In the first phase,a cognitive sensor node SU1 scavenges energy from the primary transmission.In the second phase,another sensor node SU2 and primary transmitter simultaneously transmit signals to the SU1.In the third phase,the node SU1 can assist the primary transmission to acquire the opportunity of spectrum sharing.Joint decoding and interference cancellation technique is adopted at the receivers to retrieve the desired signals.We further derive the closed-form expressions for the outage probabilities of both the primary and secondary systems.Moreover,we address optimization of energy harvesting duration and power allocation coefficient strategy under performance criteria.An effective algorithm is then presented to solve the optimization problem.Simulation results demonstrate that with the optimized solutions,the sensor nodes with the proposed cooperative spectrum sharing scheme can utilize the spectrum in a more efficient manner without deteriorating the performance of the primary transmission,as compared with the existing one-directional scheme in the literature.
文摘为解决ZigBee Cluster-Tree路由算法路径选择不优的问题,提出了一种能量感知的ZigBee树型路由EZTR(Energy-Aware ZigBee tree routing)算法.该算法利用每个节点感知的地址信息,按照ZigBee网络树型结构计算下一跳邻居节点到目的节点之间的跳数可避免网络的环路效应,通过引入认知概念,在跳数集合中选出最短路径以降低跳数.在ZigBee网络节点能量的感知过程中,当所选路径存在低能量节点时,及时启用备用节点,从而避免节点因能量过度消耗成为失效节点.NS2(Network simulator version 2)仿真实验表明,EZTR算法可提高网络分组递交率,有效减少节点转发跳数和平均网络延时,减小网络整体能耗,为提高网络的实时性和延长网络生命周期提供理论支持.
