A Utility-based Framework for Joint Channel, Topology, and Routing Control in Wireless Mesh Networks⋆

We define a utility-based framework for joint channel assignment, topology control and routing in multi-rate multi-radio wireless mesh networks, and present a greedy algorithm for solving the corresponding optimization problem. A key and novel feature of the proposed approach is the support for different target objectives, which are defined as utility functions of the MAC layer throughput, that allow operators to express different requirements in terms of throughput and availability. Such flexibility is important in future access networks. 1 Motivation and Contribution Channel assignment in wireless mesh networks influences the contention among wireless links and the network topology or connectivity between mesh nodes. Indeed, there is a trade-off between minimizing the level of contention and maximizing connectivity, e.g. see [3, 2]. Moreover, channel assignment determines the interference between adjacent channels; such interference exists not only for 802.11b/g, but contrary to common belief also for 802.11a when the distance of antennas is small [1], e.g. when they are located in the same mesh node. Finally, channel assignment influences the connectivity of mesh nodes with wired network gateways, which is a key application of wireless mesh networks. The contribution of this work is twofold: First, we formulate a new utilitybased framework for joint channel assignment and topology control in multi-rate multi-radio wireless mesh networks, which can be extended to incorporate routing. Second, we propose a greedy channel assignment procedure for solving the corresponding optimization problem. The proposed approach has the following key features: 1) channel assignment can be performed with different target objectives, which can reflect different operator-dependant requirements, 2) target objectives are expressed as utility functions of the MAC layer throughput, which captures transmission rate diversity, and 3) the approach efficiently utilizes multiple wired network gateways, and ensures that for every mesh node there exists at least one path to a gateway. Key differences with related work are that we consider throughput estimations in the channel and topology control ⋆ This work was supported in part by the European Commission in the 7th Framework Programme through project EU-MESH (Enhanced, Ubiquitous, and Dependable Broadband Access using MESH Networks), ICT-215320, http://www.eu-mesh.eu