Static Channel Assignment for Multi-Radio Multi-Channel Multi-Hop Wireless Networks

Multi-radio multi-channel multi-hop wireless networks recently have drawn considerable research attention. A number of results have been presented on joint optimization of routing, link scheduling, and channel assignment in such networks. Although dynamic channel switching has some benefits, it also poses a number of challenges in managing the network protocols and causes delay in switching channels. In this paper, we study the static channel assignment problem by statically mapping a channel to each radio of the nodes. We first show that it is NP-complete to find a channel assignment such that the resulting network is connected while the number of assigned channels to each node is at most the number of its Network Interface Cards(NICs). Secondly, we give several novel methods that only use a small number of channels while resulting in a connected network. Thirdly, we present a novel method to assign channels such that the network will support a large number of simultaneous transmissions (thus possibly increasing the network throughput). Fourthly, We theoretically analyze the expected number of channels that a node needs to be able to operate so that it can result in a connected network with high probability. Finally, we conduct extensive simulations to study the performances of our algorithms. Our simulations show that our backbone based channel assignment method will give us a connected network without violating the NIC constraints with high probability.