WSN中基于中继选择的DH-MSMR-CARQ时延与吞吐量分析

为提高无线传感器网络（WSN）的时延和吞吐量性能，提出了一种两跳多源多中继协同自动重传请求（DH-MSMR-CARQ）协议。建立最大比合并（MRC）下两种不同中继选择的DH-MSMR-CARQ协议Markov链模型，分别给出状态空间。基于截短，由各自的平均分组差错率和状态转移概率矩阵推导协议的平均传输时延和吞吐量解析表达式。数值模拟结果表明，源节点数、分组长度及最佳中继节点到目的节点的分组差错率是影响平均传输时延的关键因素，采用第一种中继选择方式具有更高的吞吐量。另外，在非极端恶劣信道环境下（源节点到中继节点的分组差错率小于0.8），DH-MSMR-CARQ协议比可直达的SSSR-CARQ、MSSR-CARQ和MSMR-CARQ协议具有更高的吞吐量。

Delay and throughput analysis of DH-MSMR-CARQ based on relay selection in WSN

To improve the delay and throughput performance of wireless sensor network(WSN), this paper proposed a dual-hop, multi-source and multi-relay cooperative automatic repeat request(DH-MSMR-CARQ) protocol. The paper established the Markov chain models of DH-MSMR-CARQ protocol with two different relay selections under maximum ratio combining(MRC) and gave the state spaces respectively. Based on truncation, this paper derived analytical expressions of average transmission delay and throughput according to their respective average packet error rate and state transition probability matrix. The numerical simulation results show that the number of source nodes, packet length and the packet error rate from the best relay node to destination node are the key factors affecting the average transmission delay, and the first relay selection method has higher throughput. In addition, the DH-MSMR-CARQ protocol has higher throughput than the direct SSSR-CARQ, MSSR-CARQ and MSSR-CARQ protocols in non-extreme channel environment(the packet error rates between source nodes and relay nodes are less than 0.8).