中文摘要：

研究车辆间通信交换信标消息的性能。首先通过建立马尔科夫链模型在理论上分析随着最小竞争窗口和车辆密度的变化关系信标消息的平均到达时延和广播接收率；然后对理论分析结果进行NS2仿真，仿真结果与理论分析具有一致性，表明文章提出的模型适用于研究车载网中的信标消息，对进一步研究车载网的其他性能也具有一定的参考价值。

英文摘要：

This paper discusses the performance of beacons exchanged among vehicles. Firstly, it analyzes the acceptance rate and average delay with the variation of minimum contention window size and vehicle density theoretically by building Markov Model, then studies the theoretical by results using ns-2 network simulator. The simulation results are consistent with the theoretical analysis, it demonstrats that the Markov Model proposed in this paper is suitable to be used to study the beacon performance, and the simulation results will provide some reference for further research of other performance of VANETs.