A distributed adaptive MAC protocol for efficient broadcasting in vehicular ad hoc networks

In vehicular ad hoc networks (VANETs), broadcast is a common operation to provide a vehicle to disseminate traffic information or warning messages to all the other vehicles. This paper proposes a distributed adaptive media access control (MAC) protocol, called DA-MAC, to dynamically select proper vehicles to form a connected virtual backbone for provision of efficient broadcasting in VANETs. The proposed DA-MAC protocol exploits an interleaving approach to transmit beacon frames to determine backbone vehicles to guarantee the network connectivity. To minimize the number of backbone vehicles, this study proposes several elegant rules incorporated with DA-MAC to alleviate packet collisions. Simulation results reveal that DA-MAC avoids serious packet collision compared with the IEEE 802.11 MAC and achieves a significant improvement on packet delivery ratio.