Distributed \alpha -Optimal User Association and Cell Load Balancing in Wireless Networks

• Published in: IEEE/ACM transactions on networking 2012-02, Vol.20 (1), p.177-190
• Main Authors: Hongseok Kim, de Veciana, G., Xiangying Yang, Venkatachalam, M.
• Format: Article
• Language: English
• Subjects: Admission control; Delay; Delay-optimal; flow-level dynamics; Interference; Load balancing; Load balancing (computing); Load management; Mapping; Mobile communication; Networks; Optimization; Policies; Servers; throughput-optimal; Traffic engineering; user association; wireless network; Wireless networks
• ISSN: 1063-6692; 1558-2566
• DOI: 10.1109/TNET.2011.2157937

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 α-optimal user association. We prove that the optimal load vector ρ * 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. We then address admission control policies for the case where the system is overloaded. For an appropriate system-level cost function, the optimal admission control policy blocks all flows at cells edges. However, providing a minimum level of connectivity to all spatial locations might be desirable. To this end, a location-dependent random blocking and user association policy are proposed.