Network-Aware Double-Layer Distance-Dependent Broadcast Protocol for VANETs

Dissemination of traffic information over multiple hops in vehicular networks requires scalability measures that prevent network congestion and avoid wasting network capacity with unnecessary information forwarding. This issue is even more important if such traffic information coexists with critical safety information. In particular, a viable solution for traffic information dissemination is piggybacking compressed information over periodic basic safety messages. Leveraging this technique, we propose a network-aware double-layer distance-dependent protocol for fast broadcasting of aggregated traffic information over multiple hops. The first distance-dependent layer uses a message size control scheme and a probabilistic approach to ensure that the forwarding within each hop is as fast as possible. The second layer progressively decreases the forwarding rate of subsequent hops as the distance from the source increases. Jointly, the two layers considerably reduce the overall latency of information while also improving the scalability and robustness of the system. We evaluate the performance of the algorithm and compare it with the existing methods, using ns-3 simulations. The results confirm that significant improvement in performance is possible without complicating the forwarding algorithm.