Spanner Based Distributed Channel Assignment in Wireless Mesh Networks

In this paper, we propose a distributed algorithm for channel assignment in multi-radio, multi-channel mesh networks. Channel assignment in multi-radio mesh networks is complicated because, in addition to affecting the interference between spatially closely located links, binding interfaces to channels affects the topology of the network. If the channel assignment is done without taking the topology into consideration, distance between any two nodes may increase arbitrarily. We propose a novel distributed channel assignment algorithm that reduces interference and at the same time provides bounds on the distance between any two nodes in the topology resulting from channel assignment. Our algorithm is based on the concept of spanners. We also develop and implement a modification of AODV, which uses the cumulative metric WCETT [4] as the routing metric. We use this routing algorithm to analyze the performance of our channel assignment algorithm. Through extensive simulations in NS-2, we show that the proposed channel assignment algorithm provides nearly 30% improvement in throughput over a simple, minimal-connectivity preserving channel assignment algorithm.