Deployment strategies of access points for outdoor wireless local area networks

In this paper, we investigate the issues of deploying access points for wireless local area networks (WLANs) in an outdoor environment, where several adjacent access points (APs) forms a cluster and in each cluster access points are connected through wireless repeaters to ease deployment. Access points are usually placed aiming to maximize its cell coverage. Nevertheless, a larger coverage distance leads to a lower throughput for the wireless repeater. We apply the mixed-integer nonlinear programming (MINLP) optimization approach to determine the number of access points in a cluster and the best separation distance between access points. The objective is to maximize the ratio of the total carried traffic load to the total cost for a cluster of APs connected by wireless repeaters. In this paper, the uniform-spacing and the increasing-spacing placement strategies for access points are proposed and compared. Our results show that the increasing-spacing placement strategy outperforms the uniform-spacing placement strategy in terms of an objective function considering total carried traffic load, the number of access points, and the cost connecting an AP to the backbone network.