A cooperative medium access control protocol with priority-based contention (PBC-CMAC) was presented for wireless networks. In the protocol, a source node preselected two optimal relays from its local relay information table, and set their priorities in cooperative request-to-send (CRTS) packet based on the relay efficiency, which reflects the degree of its saved transmission time. Through overhearing the handshakes between the source node and destination node, the two candidate relays can obtain instantaneous transmission rate among source node, destination node and themselves, and then contend to be the final relay without contention collisions according to their priorities and rate information. The proposed protocol can rapidly select the optimal relay to cooperatively transmit data packets under current channel quality without contention collisions from all the potential relays, increase the successful probability of relay selection and cooperation efficiency, and then improve multiple access performance. Simulation results show that the proposed protocol outperforms IEEE 802.11 request-to-send/clear-to-send (RTS/CTS) and CoopMAC protocols.%提出了一种适于无线网络的基于优先级竞争的协作媒质接入控制(PBC-CMAC)协议.该协议首先由源节点根据本地中继信息表选择2个最佳候选中继节点,以反映缩短传输时间程度的中继效率值区分优先级,并在CRTS分组中宣布.被选择的候选节点通过侦听源节点与目的节点交换的控制分组,可得到即时的相关速率信息,并结合自身优先级无冲突竞争成为最终的中继节点.该协议可以从所有可能的中继节点中快速、无冲突地选择出适于当前信道质量状态的最佳中继节点进行协作传输,提高了中继节点选择的成功率和协作效率,改善了网络接入性能.仿真结果表明,与IEEE 802.11 RTS/CTS和CoopMAC协议相比,PBC-CMAC协议有效提高了无线网络的多址性能.
展开▼
