Reducing Handoff Latency for NEMO-Based Vehicular Ad Hoc Networks

In a vehicular ad hoc network, vehicles can communicate with their correspondent nodes through the Internet using various wireless technologies. This kind of wireless networks brings a lot of new applications to metropolitan networks, such as online games, VoIP, etc. However, compared with traditional wireless networks, the high speed of vehicles and the limited transmission range of antennas introduce more frequent handoffs. During the handoff, vehicles have to switch their access points to establish new connections and the current wireless communications will be ceased temporarily. Therefore, long handoff latency causes poor throughput and obvious jitter. In this paper, a fast handoff scheme is proposed for vehicular networks. Using this scheme, vehicles are divided into different clusters; and within each cluster, the network mobility solution is used to reduce the total number of handoffs. Moreover, before the mobile routers start actual handoff process, they can receive their new care of addresses through assistant nodes in the same cluster. Simulation results demonstrate that handoff latency can be significantly reduced by our scheme.