A Distributed Constraint Optimization Algorithm for Dynamic Load Balancing in WLANs

The traffic load of Wireless local area networks (WLANs) is often distributed unevenly among access points. In addition, interference from collocated wireless devices operating in the same unlicensed frequency band may cause WLANs to become unstable, leading to temporarily failures of access points. This paper addresses how to dynamically balance the load and how to quickly respond to instability in WLANs. We propose a new decentralized load balancing framework for WLANs based on multi-agent systems, which maps the WLAN load balancing problem into a distributed constraint optimization problem. A distributed optimization algorithm, DLB-SDPOP, is designed to solve this problem and dynamically balance WLAN load in a fully distributed way. It focuses on pseudo-tree repair instead of pseudo-tree reconstruction each time when instability problems occur. We empirically show that the proposed distributed constraint optimization algorithms improve WLAN load balancing performance significantly.