Location Management in Heterogeneous VANETs: A Mobility Aware Server Selection Method - (Invited Paper)

Heterogeneous wireless networks are capable of providing customers with better services while service providers can offer more applications to more customers with lower costs. Many services require the support of location management functions, which still need further innovations to become viable in multi-hop vehicular ad-hoc networks (VANETs). High mobility in vehicular networks causes conventional location management systems to overuse the bandwidth and induce extra handovers to clients trying to synchronize themselves to location servers. We provide a routing algorithm for transactions between location servers and mobile nodes. We assume location servers are vehicles equipped with at least one long range and one short range radio interfaces, whereas regular nodes (clients) only need a short range radio interface. The primary goal of our design is to minimize handovers between location servers while limiting the delays of location updates. Taking advantage of vehicle mobility, we propose a mobility-aware server selection scheme and show that it can reduce the number of handovers and yet avoid large delays during location updates. We model the proposed scheme in NS-2 and apply vehicular mobility patterns generated with SUMO for urban and highway scenarios for performance evaluations. We show that proposed scheme significantly lowers the costs of signaling and rate of server handovers by increasing the connection lifetime between clients and servers.