On Optimization of Joint Channel Assignment and Routing in Mobile Ad Hoc Networks

In multi-channel multi-interface mobile ad hoc networks (MANETs), channel assignment and routing can be conducted jointly to improve network capacity. In this paper, we first extend an existing joint channel assignment and routing scheme (J-CAR) to support bidirectional path setup. Compared with unidirectional path setup schemes, the amount of broadcast control traffic and path setup delay is roughly halved. Then, a new channel interference index is designed to facilitate channel selection at each hop. Since both distance and the number of interfering sources are considered, the new interference index allows channels with better quality to be selected first. To further improve network capacity, the loading in the network should be balanced. To this end, a new length-constrained widest-path routing algorithm is designed, where the "width" of a path is determined by the interference level of its bottleneck link. With an adjustable threshold on the path length (with respect to the shortest path), the excessively long path can also be avoided. Simulation results show that, due to the improved load balancing and channel selection performance, our new joint channel assignment and routing algorithm (J-CAR/widest) outperforms the existing J-CAR and its two variants (J-CAR+index and J-CAR+widest) by delivering higher system goodputs and lower end-to-end packet delays.