一种新颖的车载网性能分析模型
Novel performance analysis model for VANET

针对目前车载网（VANET）容量和传输时延估计的研究均为渐近分析，网络拓扑一般为一维，没有考虑具体的应用场景的问题，文中提出了一种用于估计基于交通安全应用场景和IEEE 802.11p标准的二维车载网吞吐量容量和传输时延等性能指标的分析模型。该模型将每一个生成和广播安全信息数据包的节点用M/G/1队列模拟，并将IEEE 802.11p标准的带冲突避免的载波侦听多址访问（CSMA/CA）机制抽象为一个半马尔可夫过程。通过试位法求解模型参数，得出VANET性能指标的理论值。移动模型仿真软件BonnMotion和网络仿真器NS 3的仿真结果验证了分析模型理论值的正确性。
The available studies on VANET capacity and delay are all about asymptotic analysis and of one dimensional topology, without considering the specific application scenarios. This paper proposes an analysis model to evaluate the throughput and delay of two dimensional VANET for the IEEE 802.11p compliant transportation safety applications. In the model, the nodes are assumed as M/G/1 queues, which generate and broadcast safety message packages. The carrier sense multiple access with collision avoidance (CSMA/CA) scheme of IEEE802.11p standard is assumed as a semi Markov process (SMP). The model is solved by the method for attempting positions. The analytic results of the VANET performance are derived using the model and are verified by simulations with BonnMotion and NS 3