Integrated routing and MAC scheduling for single-channel wireless mesh networks

This paper presents an integrated routing and MAC scheduling protocol (IRMA) for multihop wireless mesh networks. The IRMA approach is motivated by the fact that the overall performance achieved by conventional layered approaches (802.11 MAC combined with independent ad hoc routing protocols) is significantly lower than the underlying network capacity. We propose to integrate the routing and MAC into a single protocol layer and use joint optimization techniques to establish end-to-end path and TDMA schedules for flows across the network. This approach achieves non-conflicting allocation of channel resources based on global or local traffic flow specifications and the network graph. The proposed method not only establishes interference-free MAC link schedules, but also helps to find optimal routes which can route around congested areas of the network. Two specific IRMA algorithms are proposed and evaluated in this paper. The first method solves min-hop routing, then optimizes link scheduling based on routing results and real-time flow demands. The second approach attempts to optimize routing and scheduling decisions simultaneously, using available MAC bandwidth information to route around congested areas. Both centralized and distributed algorithms based on these methods are proposed and evaluated with detailed simulations. Results show significant 2-3x improvements in network throughput when compared with baseline 802.11-based mesh networks using independent routing protocols.