车载自组网城市环境信道传播模型设计与仿真

Design and simulation of channel propagation model for vehicular Ad Hoc network under urban environment

针对车载自组网(VANET)在城市环境中信道传播模型不真实的问题,提出了一个考虑障碍物影响的信道传播模型。首先,通过地图位置处理把信号的传播分为直接的视距传输、经过1次转向的非视距传输和禁止传输三类;其次,给出了视距与非视距传输下接收端的接收功率表达式;最后,推导了Nakagami分布下的分组传递率。理论分析和洪泛广播协议仿真实验结果表明,该模型有效反映了信号传播受路旁障碍物影响的真实情况,在轻负载的稀疏场景降低了31.4个百分点的覆盖率,而在重负载的稠密场景则提升了13.32个百分点的覆盖率。所提模型模拟了5.9 GHz高频信号的直线传输效应,为通信协议的设计策略以及真实的VANET仿真提供了依据。

Since the channel propagation model for Vehicular Ad Hoc NETwork （VANET） is unrealistic in the urban environment, an propagation model considering the impact of obstacle was proposed. Firstly, using the position of the vehicle in the digital map, the propagation of the signal was classified into three types： Line Of Sight （LOS）, Not Line Of Sight with one （NLOS-1） turn and prohibitive propagation. Secondly, the expression of the received signal power was introduced under the conditions of LOS and NLOS-1. Finally, the packet delivery ratio with Nakagami distribution was deduced. Theoretical analysis and simulation results show that the model can reflect an realistic propagation of the signal which is hindered by the obstacles at roadside, the reachability is decreased by 31.4 percentage points in light load and sparse network, while it is increased by 13.32 percentage points in heavy load and dense network. The rectilinear propagation effect of the high frequency 5.9 GHz signal was simulated by the proposed model, which provides a basis for the communication protocol design and the realistic simulation of VANET.