Multicast with cooperative gateways in multi-channel wireless mesh networks

Wireless mesh networks (WMNs) are emerging as a promising solution for pervasive and cost-effective broadband connections. In this paper, we target high-throughput multicast that combats the interference and bandwidth limitation of wireless channels, which are particularly severe with wireless meshes. We suggest that they can be addressed by introducing multiple cooperative mesh gateways and exploiting the diversity of wireless channels. We present a cross-layer design that jointly selects appropriate channels for each mesh node to use at judiciously tuned power, and computes the optimal multicast flows from multiple cooperative gateways. We show that this design can be iteratively optimized through Lagrange relaxation and primal-dual decomposition. A progressive channel assignment and power level adjustment heuristic is introduced in the MAC/PHY layer, together with a smart link capacity allocation for cooperative gateways in the network layer. Through extensive simulations, we demonstrate the effectiveness of the proposed solution framework and the sub-problem heuristics. In particular, a throughput improvement of up to 100% is observed compared to straightforward approaches of utilizing multiple wireless channels for multicast routing.