Load Balancing of Best Effort Traffic in Wireless Systems Supporting End Nodes with Dual Mode Capabilities

We consider a wireless system consisting of a wireless wide area network (WAN) that cooperates with a set of wireless local network (WLAN) access points to serve a spatially distributed customer base. We assume that WAN and WLAN utilize orthogonal, i.e. non-interfering technologies, and that users’ devices are equipped with dual-mode interfaces which enable them to communicate with both the WAN and the WLANs. We focus on the downlink and address the problem of optimal interface selection (decision-making) in order to minimize the total queueing backlog in the system. We start by considering an isolated WAN cell and describe algorithms for centralized and distributed implementation for optimal decision-making. We show via simulations that our proposed algorithms enable significant performance gains over more natural strategies (based on proximity) that we use as a benchmark for comparison. We then turn to a multi-cell scenario, and show how one can modify decisionmaking to factor in the other-cell-interference in the WAN. We construct simulation examples that demonstrate the value of such modifications for achieving better system performance.