Abstract: Taking the number of isolated nodes, the maximum connectivity length, the global network efficiency and other parameters as quantitative indicators to evaluate connectivity, the Vehicular Ad-hoc Networks（VANETs） is established by VanetMobisim and the evolution of VANETs connectivity is studied under the Nakagami fading channel model and deterministic channel model in detail. As the results show, the temporal correlation of networks is weak when VANETs is fully connected. When the connectivity of VANETs is low, all the connectivity indexes present heavy-tailed phenomenon and the network connectivity has a strong temporal correlation. Finally, the influence on the connectivity of VANETs is analysed led by the nodes density, path loss index and fading factor etc.

Key words: vehicular ad hoc networks, connectivity, fading channel model, deterministic channel model, temporal correlation

摘要： 以孤立节点数、最大连通长度、全局网络效率等参数为连通性量化指标，应用VanetMobisim车辆仿真软件建立车载自组织网络，详细研究在Nakagami衰落信道模型和确定信道模型下VANETs连通性随时间的演化特征。结果表明当VANETs全连通时，网络时间相关性较弱，当网络连通性比较差时，各项连通性指标均呈现重尾现象，网络连通性具有很强的时间相关性。分析车辆节点密度、路径损耗指数和衰落因子等因素对网络连通性的影响。

关键词: 车载自组织网络, 连通性, 衰落信道模型, 确定信道模型, 时间相关性