A Distributed Infrastructure-Based Congestion Avoidance Protocol for Vehicular Ad Hoc Networks

In order to detect and reduce the congestion level in downtown areas, many research works and projects have been proposed. The previous works have been based on the information gathered at a central database to recommend the best path for vehicles, which introduces a bottleneck problem as well as a single point-of-failure. In this work we propose a dynamic and real time protocol that intends to find the fastest path towards each destination in a distributed fashion, without the need for a centralized database. The proposed protocol recommends paths that will allow vehicles to avoid highly congested road segments towards a certain destination. Moreover, this protocol can alleviate the drastic increase in congestion scenarios by distributing the traffic load over the downtown grid road segments without adversely affecting the traveling time of vehicles. In this paper, we discuss our protocol in details, compare it to other path recommendation protocols and report on its performance evaluation an extensive set of scenarios and experiments implemented on the NS-2 simulator. From the results, we can conclude that our protocol provides better performance in terms of vehicular traveling time towards each destination, without the need for a central database.