On the Planning Problem of Wireless Local Area Networks with Directional Antennas

Wireless local area networks (WLANs) are more deployed today than ever before. However, this rapid growth led to uncoordinated deployment and planning tools are rarely used. In this paper, we first propose a mathematical model to solve the WLAN planning problem considering directional antennas. The problem consists of selecting the location of the access points in the network and selecting the transmit power, the antenna type and its orientation as well as the communication channel of each one. The use of interfering channels is allowed to solve the frequency allocation problem. Since the problem is NP-hard, we propose a two-step tabu-based metaheuristic algorithm to find solutions satisfying a radio coverage constraint, a throughput constraint and an interference level constraint. Our objective is to minimize the cost of the network and to distribute evenly the resources amongst the users. The aim of the first step of the algorithm is to obtain a solution that satisfies all the constraints while the second step focuses on optimizing the previously obtained solution. A new neighborhood, based on radio coverage of an access point, is proposed. The results show that solutions can be obtained with the proposed approach for real-size instances of the problem.