中文摘要：

针对分析模型和仿真模型研究车载自组网IEEE 802.11p广播模式网络性能存在的不足,采用层次随机着色Petri网（HSCPN）对协议的媒体访问控制层进行建模,模型着重描述了消息的产生、重传、退避和虚拟碰撞的过程.在此模型的基础上,对网络性能指标进行了分析.结果表明：高优先级队列的消息具有较小的时延和时延抖动.HSCPN建模方法的采用可直观地了解协议的运行机制,有利于协议的改进,并可为车载自组网的部署提供理论依据.

英文摘要：

Due to the shortages of the analytical model and simulation model, hierarchical stochastic colored Petri net has been proposed to model the media access control layer of IEEE 802.11 p, which is used for investigating the broadcast performance of vehicular ad hoc networks. The proposed model has been used to describe the generation, retransmission, backoff and internal collision process. Then, the per- formance metrics have been simulated and analyzed. The results show that the higher priority access cate- gory has the shorter time delay and delay jitter. Moreover, the operation of the IEEE 802.11 p can be intuitively understood by using the hierarchical stochastic colored Petri net（HSCPN） model, which is helpful for the protocol improvement, and it can also provide theoretical basis for the deployment of VANETs.