Hybrid multi-technology routing in heterogeneous vehicular networks

Recent developments of wireless communication systems have resulted in the availability of heterogeneous access networks at any geographic area. To make use of this heterogeneous environment for vehicular users to access the Internet, in this article we propose a hybrid multi-technology routing (HMTR) protocol for multihop vehicular networks. HMTR takes into account different combinations of wireless technologies in intermediate hops and is generally formed of a combination of topology-based and position-based routing schemes for packet forwarding. For a given packet, HMTR uses the position-based routing approach over highly variable links whose lifetimes are shorter than the packet expiry time. On the other hand, it employs the topology-based routing approach over more stable links that are expected to stay valid before the expiry time of the packet. Among the candidate routes, any route which does not meet the user requirements in terms of budget or quality of service metrics such as delay and bandwidth is ruled out first. Then, among the remained candidates those with adequate levels of connectivity are assessed for their appropriateness in terms of network utilizations, which are of the network’s concern and connection costs, which are of users’ concern. Simulation results show that HMTR enables us to achieve the best possible performance in terms of delivery ratio and delivery delay for a given budget, whereas in pure position-based or pure topology-based routing schemes sacrificing the performance or budget may be inevitable in many scenarios.