Multipath routing for multiple description video in wireless ad hoc networks

As developments in wireless ad hoc networks continue, there is an increasing expectation with regard to supporting content-rich multimedia communications (e.g., video) in such networks, in addition to simple data communications. The recent advances in multiple description (MD) video coding have made it highly suitable for multimedia applications in such networks. In this paper, we study the important problem of multipath routing for MD video in wireless ad hoc networks. We follow an application-centric cross-layer approach and formulate an optimal routing problem that minimizes the application layer video distortion. We show that the optimization problem has a highly complex objective function and an exact analytic solution is not obtainable. However, we find that a meta-heuristic approach such as genetic algorithms (GAs) is eminently effective in addressing this type of complex cross-layer optimization problems. We provide a detailed solution procedure for the GA-based approach, as well as a tight lower bound for video distortion. We use numerical results to demonstrate the superior performance of the GA-based approach and compare it to several other approaches. Our efforts in this work provide an important methodology for addressing complex cross-layer optimization problems, particularly those involving application and network layers.