基于车联网的广播MAC协议性能分析

针对车载自组织网络IEEE802.11协议中媒体访问控制(medium access control,MAC)层一维广播性能分析模型不适用于小竞争窗口的问题,提出一种考虑了连续冻结过程(consecutive freeze process,CFP)现象的二维马尔科夫模型。将CFP映射为连续发送分组过程和连续退避冻结过程,分析得出饱和状态下节点各状态转移的概率,并推导出节点广播分组的性能表达式。仿真结果表明,与一维分析模型相比,即使是在争用信道的竞争窗口较小情况下,该二维分析模型也能很好地预测饱和状态下节点广播分组的平均时延、吞吐量和成功接收率。

PERFORMANCE ANALYSIS OF BROADCASTING MAC PROTOCOL BASED ON VEHICULAR AD HOC NETWORKS

This paper proposed a two-dimensional Markov model considering consecutive freeze process(CFP) to solve the problem that the one-dimensional broadcasting performance analysis model of media access control(MAC) layer in the vehicular Ad Hoc Network 802.11 protocol was not suitable for small contention windows.The CFP was mapped to the continuous sending packet process and the continuous back-off freezing process.We analyzed the probability of node state transition under saturation state,and deduced the performance expression of node broadcast packet.The simulation results show that compared with the one-dimensional analysis model,the two-dimensional analysis model can predict the average delay,throughput and successful reception rate of broadcast packets in saturated state,even when the competition window of the competing channel is small.