Using a relaying system to provide spatial diversity and improve the system performance is a tendency in the wireless cooperative communications. Amplify-and-forward （AF） mode with a low complexity is easy to be imp...Using a relaying system to provide spatial diversity and improve the system performance is a tendency in the wireless cooperative communications. Amplify-and-forward （AF） mode with a low complexity is easy to be implemented. Under the consideration of cooperative communication systems, the scenario includes one information source, M relay stations and N destinations. This work proposes a relay selection algorithm in the Raleigh fading channel. Based on the exhaustive search method, easily to realize, the optimal selection scheme can be found with a highly complicated calculation. In order to reduce the computational complexity, an approximate optimal solution with a greedy algorithm applied for the relay station selection is proposed. With different situations of the communication systems, the performance evaluation obtained by both the proposed algorithm and the exhaustive search algorithm are given for comparison. It shows the proposed algorithm could provide a solution approach to the optimal one.展开更多
提出一种车载自组织网络(VANET)中考虑节点质量的机会路由协议——QAOR(Quality of node based Adaptive Opportunistic Routing Protocol)。针对以往协议均没考虑到节点历史接触频繁性的问题,该协议在路口根据距离目的最近和反映节点...提出一种车载自组织网络(VANET)中考虑节点质量的机会路由协议——QAOR(Quality of node based Adaptive Opportunistic Routing Protocol)。针对以往协议均没考虑到节点历史接触频繁性的问题,该协议在路口根据距离目的最近和反映节点接触频繁性的质量两个指标机会选择下一跳,改善了GPSR在路口下一跳没有后续节点的情况;在直路上运用加入携带转发机制的贪婪算法。NS-2仿真显示,在城市场景中,QAOR自适应选路,比传统贪婪算法GPSR投递率增加,延时减少。展开更多
基金supported by National Science Council under Grant No.101-2221-E-029-020-MY3
文摘Using a relaying system to provide spatial diversity and improve the system performance is a tendency in the wireless cooperative communications. Amplify-and-forward （AF） mode with a low complexity is easy to be implemented. Under the consideration of cooperative communication systems, the scenario includes one information source, M relay stations and N destinations. This work proposes a relay selection algorithm in the Raleigh fading channel. Based on the exhaustive search method, easily to realize, the optimal selection scheme can be found with a highly complicated calculation. In order to reduce the computational complexity, an approximate optimal solution with a greedy algorithm applied for the relay station selection is proposed. With different situations of the communication systems, the performance evaluation obtained by both the proposed algorithm and the exhaustive search algorithm are given for comparison. It shows the proposed algorithm could provide a solution approach to the optimal one.
文摘提出一种车载自组织网络(VANET)中考虑节点质量的机会路由协议——QAOR(Quality of node based Adaptive Opportunistic Routing Protocol)。针对以往协议均没考虑到节点历史接触频繁性的问题,该协议在路口根据距离目的最近和反映节点接触频繁性的质量两个指标机会选择下一跳,改善了GPSR在路口下一跳没有后续节点的情况;在直路上运用加入携带转发机制的贪婪算法。NS-2仿真显示,在城市场景中,QAOR自适应选路,比传统贪婪算法GPSR投递率增加,延时减少。
文摘针对车辆节点快速移动和非均匀分布导致的车联网网络空洞问题,以及空洞节点采用SCF(store carry forward)方法长期携带过时交通信息导致浪费存储资源的问题,提出一种先应式空洞发现策略以及一种限时携带的贪婪前传广播(CGFB,limited time carry and greedy forward broadcast)方法.CGFB结合了GF(greedy forward)算法和SCF算法的优点,可以提高建立路径的成功概率并降低存储消耗.仿真结果表明,当平均邻居节点数大于4时,CGFB算法成功建立路径的概率可达97%以上;相比SCF算法,当平均邻居节点数为2时,可节省90%以上的存储资源.
