WLAN planning: Separate and joint optimization of both access point placement and channel assignment

Abstract

In this paper, we are interested to the prob- lem of designing wireless local networks (WLANs), which involves deciding where to install the access points (APs), and assigning frequency channels to them with the aim to cover the service area and to guarantee enough capacity to users. Our proposal provides different solutions to the prob- lems related to the WLAN design and can be divided into two main parts. In the first part, we focus on the prob- lem of designing a WLAN by treating separately the AP positioning and the channel assignment problems. For AP positioning issue, we formulate it as a set covering problem. Since the computation complexity limits the exact solu- tion, we propose two heuristics to offer efficient solution. While, for the channel assignment, we define this issue as a minimum interference frequency assignment problem and propose three heuristics. Two heuristics aim to minimize the interference at AP locations. Whereas, the objective of the third heuristic is to minimize the interference at the TPs level. In the second part, we treat jointly the two aforementioned issues based on the concept of virtual forces. In this case, we start from an initial solution provided by the separated approach and try to enhance it by adjusting the APs’ positions and reassigning their operating frequen- cies. In each part of this work, we start first by describing the problem, then presenting the algorithms proposed to resolve it efficiently and finally we illustrate the obtained results and analyze them.