交通路口场景下基于 802. 11p 的车队通信性能分析模型

As one of the key technologies of automated driving, platooning strategy has been extensively studied and tested in practice. When platoons pass through the traffic intersection controlled by traffic light, kinetic parameters such as traffic light time, intra/inter-platoon spacing, speed, and moving direction are severely affected. At this time, since the platooning communication connectivity network is complex and variable, the driving stability of platoons is difficult to maintain, thus resulting in that the vehicles in platoons that communicate through 802. 11p protocols cannot receive the complete important information within the specified delay limit, which finally leads to road safety issues. To solve this problem, considering the Enhanced Distributed Channel Access (EDCA) mechanism of the 802. 11p protocol, which supports data of 4 transmission priorities to access channel, a novel communication performance analysis model for automated driving platoons under traffic intersection scenario is proposed. First, we build a connectivity network of vehicular communication at the traffic intersection and obtain the network communication performance through constructing the platoon moving model. Then, the classic Markov model that describes the 802. 11p EDCA mechanism is transformed into a z-domain linear model by utilizing the method of probability generating function, and the platooning communication delay and packet delivery ratio (PDR) analysis model is deduced according to the priority differences of the 4 access categories. Finally, iterative method is used to calculate the platooning communication delay. The simulation results verify the accuracy of the analysis model, and it can be found that when passing through the intersection, the communication delay of platoons is lower than the 100ms specified by the 802. 11p protocols and the packet delivery ratio is higher than 0. 95, which ensures the timeliness and completeness of the platoon communication.