Minimum AP Placement for WLAN with Rate Adaptation Using Physical Interference Model

There are two widely used interference models to characterize interference in wireless communication, protocol model and physical model. The protocol model simplifies the interference by considering only two concerned communication links (or nodes). It ignores the cumulative interference from other links (or nodes). On the other side, the physical model considers the cumulative interference of the ambiance, but its application is very much limited due to the complexity to compute the physical interference of the whole system. In this paper, we study the AP placement problem in the physical interference model. By assuming a simple scheduling method, we propose a heuristic algorithm aiming to find the placement of minimal number of APs in an indoor region to meet the end users´ QoS requirements. From the simulation results, we find that there is a significant difference in performance between the algorithms that use the physical model and the protocol model. It shows that the results obtained from AP placement algorithm in the protocol model are not close to the real situation due to neglect of cumulative interference.