车联网城市交通移动多场景建模仿真及分析

Modeling and Analyzing of Urban Traffic Mobile Scenes for Vehicular Ad Hoc Networks

本文针对车载自组织网络环境中的城市交通车辆移动应用场景进行了分析,在VanetMobiSim交通仿真器和NS-2网络仿真器协同仿真环境中,对城市智能交通中的两类典型应用场景交叉路口和双向快速四车道进行了模型构建,同时在这两类应用场景中对AODV和DSDV路由协议进行了仿真和分析.通过端到端时延、抖动率、丢包率和控制包开销四个评价指标对比不同协议在同一场景下的表现效果.此外,针对AODV协议,分析了车辆速度、车辆密度、最大联机数和单位时间内发送封包数等环境因子对协议通信效果的影响.仿真结果表明,选取合适的移动场景模型有助于客观评价协议性能,不同的协议对不同的场景的表现性和适应性不同. DSDV应用于简单稳定的移动场景时表现较优,而AODV面对复杂多变的移动场景时有更好的适应性,且AODV协议受网络拓扑复杂程度和结构变化频率影响较大.

The mobility scenes of urban transport applications in the vehicular Ad Hoc networks is analyzed in this study.Based on the VanetMobiSim traffic simulator and NS-2 network simulator, two kinds of typical scenarios of urban intelligent traffic were built, which are Models of junction and two-way fast four-lane, and the AODV and DSDV routing protocols were simulated and analyzed in these two scenarios simultaneously. Four evaluation indicators which include end-to-end delay, jitter rate, packet loss rate, and control packet overhead, are introduced to evaluate and compare the performances of different protocols in the same scene. In addition, in the simulation experiments of AODV, the effects resulted from vehicle speed, vehicle density, the maximum number of connections, and the number of packets sending per unit time are also analyzed. The simulation result shows that selecting the appropriate mobility scene model helps to evaluate the performance of the protocols objectively, different protocols present different performance and adaptability in different scenarios. DSDV performs better when applied to simple and stable mobile scenarios, while AODV has better adaptability to complex and ever-changing mobile scenarios. Moreover, AODV protocol is greatly affected by the complexity of network topology and the frequency of the change in structure.