Alliance based approach for reducing saturation and congestion in VANETs

Vehicular Ad hoc Networks (VANETs) have received special attention from scientists because of their importance in daily life. In VANETs, we mainly find fixed entities (Road Side Units “RSUs”) and mobile entities (vehicles). In order to exchange information and data relating to the safety and comfort of road users, these different entities must establish communications between them. In these communications, one of the main problems is related to congestion and saturation of RSUs. To solve this problem, we propose in this paper a new approach of cooperation between the RSUs of a VANET in order to reduce its congestion and thus to avoid as much as possible the saturation of these RSUs. This approach, called “D2A2RS” (Defensive Alliance based Approach for Reducing RSUs Saturation), is based on the concept of defensive alliances in graphs that ensures efficient collaboration between the RSUs. Furthermore, we propose two analytical models based on Markov chains to compare our D2A2RS protocol with a concurrent protocol (IAGR). The obtained comparaison results have shown the efficiency and the performance of our approach in terms of packet loss.