Performance Study of CAM over IEEE 802.11p for Cooperative Adaptive Cruise Control

The IEEE 802.11p is the de-facto vehicular radio communication technology for road safety and efficiency applications. With the advancements in the autonomous vehicle technology, studies on applicability of the IEEE 802.11p and the related protocols for the autonomous driving applications are needed. In this paper, we study the impacts of vehicular communication on platooning control considering that the ETSI-standardised message set Cooperative Awareness Message (CAM) and the IEEE 802.11p are used for both the platooning and cooperative awareness applications. We first develop a theoretical model for the probability of a successful CAM transmission over IEEE 802.11p between platoon members by taking account of the existence of non-platoon vehicles on the road. The model is verified by comparing against simulation results obtained from the NS3 simulator. Finally, we investigate the impacts of the communication performance on the behaviour of platoons, specially the chain stability, when hundreds of vehicles share the wireless channel. The theoretical model reveals that thanks to the capture effect, communications between platoon members drastically outperform communications between arbitrary two vehicles on the road. The simulation results show that in contrast to an adaptive cruise control (ACC), which does not use vehicular communication, the IEEE 802.11p based vehicle to vehicle (V2V) communication aids for realizing stable platoons in highway scenarios.