RMRPTS: a reliable multi-level routing protocol with tabu search in VANET

Vehicular ad hoc network (VANET), a subclass of mobile ad hoc networks (MANETs), is a promising approach for the intelligent transportation system (ITS). One of the main challenges in VANETs is establishment of vehicular communication and stable routing. Another problem of VANETs is their tendency of being trapped in a local optimum. In this paper, a reliable multi-level routing protocol based on clustering, RMRPTS has been introduced in VANETs. Even if this topology constantly changes, clustering based multi-level routing will create the possibility of self-organization and route maintaining; moreover, it will solve the problem of developing a trap in the local optimum using tabu search. At the first level, the proposed protocol is an extension of AODV routing protocol that has been improved using fuzzy logic in order to create reliable routing between cluster members. Tabu search has been used at a higher level for routing between cluster heads and destination. Tabu search is a meta-heuristic improved learning method used for solving hybrid optimization problems, and it uses cost function to select a solution among a set of possible solutions. The effective parameters used in the proposed method to select the best path include nodes distance, the velocity of nodes, node's angle, link stability, and link reliability. The proposed protocol was simulated using an NS-2 simulator, and the results of its performance showed increased average packet delivery rate and decreased average end to end delays, number of packet losses compared with earlier protocols.