Channel Assignment in Multi-Radio Wireless Mesh Networks: A Graph-Theoretic Approach

In this paper, we propose a load-based scheme for assigning channels to radio interfaces in multi-radio, multi-channel wireless mesh networks. We first construct a model for channel assignment as an optimization problem with the goal of minimizing the overall network interference. The problem is proven to be NP-Hard. We then apply the Lagrangian relaxation method to obtain lower bounds as well as near-optimal feasible solutions for large size networks. We further present a meta-heuristic based on genetic algorithms, which can yield good quality solutions for very large networks. With these two centralized approaches as the benchmark, we propose a fully distributed algorithm in order to tackle the channel assignment problem practically. Our extensive simulation experiments demonstrate that the distributed algorithm performs competitively and can serve as a practical and scalable solution to the channel assignment problem.