α-Optimal User Association and Cell Load Balancing in Wireless Networks

In this paper we develop a framework for user association in infrastructure-based wireless networks, specifically focused on flow-level cell load balancing under spatially inhomogeneous traffic distributions. Our work encompasses several different user association policies: rate-optimal, throughput-optimal, delay-optimal, and load-equalizing, which we collectively denote alpha-optimal user association. We prove that the optimal load vector rho* that minimizes a generalized system performance function is the fixed point of a certain mapping. Based on this mapping we propose and analyze an iterative distributed user association policy that adapts to spatial traffic loads and converges to a globally optimal allocation.