Interface assignment and bandwidth allocation for multi-channel wireless mesh networks

With the ability of simultaneous transmissions, multi-channel multi-interface wireless mesh networks (WMNs) have emerged with great potential in the improvement of network throughput and fairness. However, most proposed channel assignment algorithms for WMNs made an assumption that the network interface cards (NICs) are evenly assigned to the mesh routers. In this paper, we investigate the problems of NIC assignment and bandwidth allocation to minimize the infrastructure cost, and meanwhile guarantee the application requirements. We argue evenly assigning NICs to all routers is neither a necessary condition nor an effective solution, since not only the interference but also the traffic flows are important factors that will affect the parallel use of the bandwidth. One of the principal challenges addressing these problems is their interactive impact on the optimization of network throughput. By analyzing all kinds of constraints for traffic, NIC and performance, we formally define a problem space that addresses the relationships between different assignment and allocation problems. Furthermore, we demonstrate that a hard NIC assignment and bandwidth allocation problem can be decomposed and formulated into a well-defined single or multiple-phase problem. In addition to the linear programming (LP) solutions, we propose novel efficient heuristics for on-line decisions for the situation whenever the network architecture changes and needs recompute the system performance in real-time. We show through extensive simulations that the heuristic algorithms can achieve close to optimal solution and outperform the equal NIC assignment method with even a smaller number of NICs. (C) 2008 Elsevier B.V. All rights reserved.