On the intermittence of routing paths in vehicle-formed mobile ad hoc networks on highways

An information network built on top of vehicles using IVC (Inter-Vehicle Communications) can be viewed as a type of mobile ad hoc networks (MANET). Due to the high mobility of vehicles, the topology of an IVC network can change rapidly and thus an established routing path can easily break. One reason for path breakage is that a vehicle moves out of the wireless transmission range of its previous or next vehicle on the path causing a wireless hop of the path to break. On highways, however, due to lane-changing and car-following among vehicles, such a broken hop may later become reconnected and cause the path to become reconnected as well. In this paper we use several vehicle mobility traces generated by a microscopic traffic simulator to answer the following question - How possible a broken path may later become reconnected if the routing protocol is willing to give it some time to recover before switching to another path. Our finding shows that the path-reconnection possibility is very tiny and it is not worth waiting for such an event to occur.