Efficient Strategies for Channel Management in Wireless LANs

We define efficient algorithms for channel management (channel assignment and load balancing among APs) in 802.11-based WLANs that lead to better usage of the wireless spectrum. These algorithms (called CFAssign) are based on a “conflict-free set coloring” formulation that jointly perform load balancing along with channel assignment. Such a formulation has a number of advantages. First, it explicitly captures interference effects at clients. Next, it intrinsically exposes opportunities for better channel re-use. Finally, algorithms based on this formulation do not depend on specific physical RF models and hence can be applied efficiently to a wide-range of in-building as well as outdoor scenarios. We have performed extensive packet-level simulations and measurements on a deployed wireless testbed of 70 APs to validate the performance of our proposed algorithms. We show that in addition to single network scenarios, CFAssign algorithms are well suited for channel assignment in scenarios where multiple wireless networks share the same physical space and contend for the same frequency spectrum. Our results over a wide range of scenarios indicate that CFAssign reduces the interference at clients by about 50-70% in comparison to current best-known techniques.

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