存在移动车辆遮挡的VANETs连通性研究

Connectivity analysis of VANETs which obstructed by mobile vehicles

针对高速公路场景下的车流移动特性以及时变的信道状态，着重考虑道路中其他移动车辆作为遮挡物对车间通信链路的影响，深入分析了车流密度、车辆速度均值以及标准误差对车联网链路连通概率的影响，采用双斜率路径损耗模型并结合车辆速度服从截断型高斯分布的车流移动特性以及两状态的Markov信道状态转移模型，推导出车辆平稳阻挡概率，以信号的传播损耗是否超出通信系统容限为依据对车联网连通性进行判决，得到通信链路连通概率。仿真结果表明，在通信距离一定的条件下，速度服从截断型高斯分布的移动遮挡物模型具有更好的连通性，同时，单位时间内达到的车辆越多，车流密度越大，平稳阻挡概率越大，网络连通性越差。

Aiming at the traffic flow characteristics and the time-varying channel state under the highway scene, this article focuses on the impact of other vehicles on the road as mobile obstructions on the communication links. The influence of traffic density, vehicle speed mean and standard error on the connectivity probability is analyzed in depth. Using dual-slope path loss model and combing the traffic flow movement characteristics which vehicle speed follows truncated Gaussian distribution with the Markov channel state transition model which contains two states, the obstructed probability is deduced. Based on whether the propagation loss of the signal is beyond the tolerance of the communication system, the expressions of VANETs connectivity probability is obtained. The simulation results show that the obstacle-based model which vehicle speed follows truncated Gaussian distribution has better connectivity performance when the communication distance is fixed. At the same time, the more vehicles arrive in the unit time, the greater the traffic density and the obstructed probability, the worse the network connectivity is.