Performance analysis of a time headway based rate control algorithm for VANET safety applications

Vehicular ad hoc network is considered as an integral part of the future intelligent transportation system. As the number of applications which are supported by the vehicular communication grow, the efficient utilization of the control channel and congestion control become important issues. The periodic broadcast of basic safety messages (BSM) by the vehicles consumes most of the control channel interval, leaving less transmission capacity for other types of traffic. To accommodate the data packets from other safety and non-safety applications, the packet transmission rate of BSM must be controlled without compromising the safety of the vehicles. In this paper, we present a BSM generation rate control algorithm based on the measured time headway of the vehicles. The performance analysis shows that the proposed rate control algorithm reduces the channel utilization and improves the BSM reception ratio at different vehicle densities and vehicle speeds. Moreover, the proposed rate control algorithm effectively reduces the notification time of a multi-hop warning message.