Congestion Control and Channel Assignment in Multi-Radio Multi-Channel Wireless Mesh Networks

We address the problem of congestion control in multi-radio, multi-channel, wireless mesh networks. Compared to its single radio counterpart for which solutions exist, this problem is significantly more complex because it requires the radio channel assignments and the traffic allocations per channel be jointly optimized. We address the problem by introducing a formulation that allows its decomposition in two subproblems: A congestion control subproblem for traffic allocation to a fixed channel assignment over a node path and a discrete combinatorial channel assignment subproblem. We solve the conditional congestion control subproblem by mapping it to an optimization problem of traffic distribution to a set of radio paths. The solution provides channel congestion information that is utilized to address the channel assignment subproblem. This leads to an iterative procedure which guarantees successive increases to overall network utilization. Compared to existing work on multiradio, multi-channel mesh networks, we show that our approach can yield significant gains both in terms of network utilization and establishing fairness.