Efficient route maintenance in wireless mesh networks

In this paper, we address the problem of route fragility in backhaul wireless mesh networks. Mesh routing protocols rely on intermediate nodes in the multihop path to forward data and detect route breakage. An intermediate node reports the link to next hop as broken after a fixed number of unsuccessful packet transmission attempts at the MAC layer. Transmission failure of a single packet on any link in the multihop path thus renders the route unusable. In practice, many transmission failures are isolated and temporary, caused by transient congestion on the wireless link. False route failures triggered by temporary transmission failures render otherwise good routes as unusable and degrade performance. We propose a novel route maintenance mechanism Congestion Aware Routing (CAR) which addresses this problem and makes a more dasiainformedpsila decision about the link status. CAR uses estimation of medium congestion and the frequency and distribution of link failures to distinguish between broken (or poor quality) links from those experiencing temporary losses. Simulation results for TCP traffic show that CAR can provide up to 15% higher throughput, 50% delay reduction with 8 times smaller routing overhead.