On deriving and incorporating multihop path duration estimates in VANET protocols

The expected duration of multihop paths can be incorporated at different layers in the protocol stack to improve the performance of mobile ad hoc networks. This article presents two discrete-time and discretespace Markov chain-based methods, DTMC-CA and DTMC-MFT, to estimate the duration of multihop roadbased paths in vehicular ad hoc networks (VANET). The duration of such paths does not depend on individual nodes because packets can be forwarded by any vehicle located along the roads forming the path. DTMCCA derives probabilistic measures based only on vehicle density for a traffic mobility model, which in this article is the microscopic Cellular Automaton (CA) freeway traffic model. DTMC-MFT generalizes the approach used by DTMC-CA to any vehicular mobility model by focusing on the macroscopic information of vehicles rather than their microscopic characteristics. The proposed analytical models produce performancemeasure values comparable to simulation estimates from the validated CA traffic model. Furthermore, this article demonstrates the benefits of incorporating expected path durations into a VANET routing protocol. Simulation results show that the network overhead associated with route maintenance can be reduced to less than half by using the expected path durations.