Impacts of Radio Access Protocols on Cooperative Vehicle Collision Avoidance in Urban Traffic Intersections

This paper presents the design of a Cooperative Collision Avoidance application, and evaluates its performance with DSRC-recommended 802.11 Medium Access Control (MAC) and with a novel Vehicular SelfOrganizing MAC (VeSOMAC) protocol. VeSOMAC is designed as a fully distributed TDMA protocol that relies on an in-band control exchange technique for autonomous TDMA slot allocation among vehicle-mounted wireless communication modules. A hybrid traffic and wireless network simulator has been developed for evaluating both network level and application level performance in the presence of different wireless access protocols. Detailed network and vehicular traffic simulation models have also been developed for evaluating a Cooperative Collision Control (CCA) application, operating in urban traffic intersection scenarios. Simulation results demonstrate that unlike the 802.11 style contention based protocols, a schedule based protocol such as VeSOMAC can offer better vehicle safety performance through smaller and bounded packet latency in vehicular ad hoc networks.