Improving routing performance in high mobility and high density ad hoc vehicular networks

In ad hoc networks the broadcast nature of the radio channel poses a unique challenge because the wireless links have time-varying characteristics in terms of link capacity and link-error probability. In mobile networks, particularly in vehicular ad hoc networks (VANETs), the topology is highly dynamic due to the movement of the nodes, hence an on-going session suffers frequent path breaks. In this paper we present a method that uses the available knowledge about the network's topology to improve the routing protocol's performance through decreasing the probability of path breaks. We propose a scheme to identify long duration links in VANETs, which are preferentially used for routing. This scheme is easily integrated in the existent routing protocols. We describe how to integrate it in the Optimized Link-State Routing Protocol 1. Finally, we evaluate the performance of our method with the original protocol. Simulation results show that our method exhibits better end-to-end path delay (almost one magnitude order lower) and packet delivery ratio (between 25% and 38% higher) than the original protocol. This observation is even more evident when the node's density increases.