Capacity Optimization of Mesh Networks

Interference and collisions greatly limited the throughput of mesh networks that used contention-based MAC protocols such as 802.11. Significantly higher throughput is achievable if transmissions are scheduled. However, traditional methods to compute such schedules are so computationally complex that they can only be used on relatively small networks. This paper presents results from several recent works on techniques to efficiently compute capacity optimizing schedules. The techniques presented allow optimal schedules to be computed for networks with hundreds and perhaps even a few thousand links, satisfying the requirements of current and planned mesh networks. The techniques have been verified on networks generated with a realistic propagation simulator, hence, the findings are directly applicable to the networks planned in urban areas such as Philadelphia and San Francisco. In this setting, it is shown that optimal scheduling increases the capacity by between a factor of four and ten over 802.11 CSMA/CA, depending on the density of the mesh routers and gateways.