Analysis of beaconing message rate in VANET multi-hop broadcast protocols

Multi-hop wireless broadcast is a critical component in Vehicular Ad-hoc Networks (VANET). Many VA NET applications, such as traffic data dissemination, utilize broadcast as a primary mode of communication. Thus creating efficient broadcast schemes is important for supporting practical VANETs. Multi-hop broadcast protocols are generally composed of two components: a rebroadcast algorithm and a beaconing scheme. Beaconing allows nodes to discover topology and exchange neighborhood information with nearby nodes. Rebroadcast algorithms often depend on this information to make retransmit decisions that determine the performance of the protocol. Thus the beaconing scheme plays a key role in the performance of the overall broadcast system. In this paper, we evaluate different types of broadcast protocols to determine beaconing rates required to support them. We test a statistical protocol, DAD, a self-pruning topological protocol, SBA, and a dominant-pruning topological protocol, MPR. Simulation results from JiST/SWANS are shown using simulated traffic mobility models for a range of overhead messaging rates. Results show that overhead-messaging requirements can vary widely between broadcast algorithms in VANET, thus highlighting the need to design efficient broadcast methods that are insensitive to rapidly changing topologies for VANET applications.