Recently, the idea of Opportunistic Routing has been widely explored to improve the performance of multi hop wireless mesh networks. Most of the previous studies use simulations or empirical measurements to evaluate the performance gain of opportunistic routing and therefore are limited to relatively few types of scenarios. In this paper, we take an analytical approach to study the potential gain of opportunistic routing in multi hop wireless networks. Unlike other analytical studies which use a deterministic channel model, our approach captures the key characteristics of opportunistic routing, i.e. its ability to take advantage of the numerous, yet unreliable wireless links in the network in a probabilistic manner and study the effectiveness of opportunistic routing under diverse radio propagation environment using lognormal shadowing and Rayleigh fading models. Our results show that, under typical network configurations and neglect overhead, the average progress per transmission of opportunistic routing in lognormal shadowing (Rayleigh fading) environment is about 3 (1.5) times higher than that of Traditional Unicast Routing. Finally, we also demonstrate the potential benefits of using different forwarding regions and directional antennas in opportunistic routing.
