A collision-based beacon rate adaptation scheme(CBA) for VANETs

Safety applications in VANET use two types of messages (a)periodical messages/beacons: they are broadcast several times per second to exchange information with neighbors; and (b) warning (event driven) messages: they are generated when an event occurs (e.g., a car accident) and are disseminated in the network to notify nodes of interest. Although warning messages have higher priority, beacons are equally as important since a good dissemination strategy usually relies on information provided by beacons to choose forwarding nodes. However, in dense networks, beacons may cause network congestion leading to performance degradation of safety applications. In this paper, we propose CBA: a congestion control approach that uses the number of detected collisions as a metric to control the beacon generation frequency and therefore reduce the effect of congestion. Simulation results show that our proposed scheme achieves a balanced trade-off between beacon information accuracy and beacon related overhead.