Transmission power optimization of concurrently communicating two access points in wireless local area network

Currently, the IEEE 802.11 wireless local-area network (WLAN) has been prevalent around the world due to the advantages of mobility, flexibility, and scalability. WLAN offers the wireless internet-access method through an access-point (AP) at homes, schools, or offices. When multiple APs are deployed in the network field, the proper transmission power of each AP is essential to improve the performance, considering the coverage area, transmission capacity, and interference. In this paper, the authors study the transmission power optimization of concurrently communicating two APs in WLAN. Based on extensive experiment results, the authors propose a method of selecting the best power for each AP from the signal-to-noise ratio (SNR) of receiving signal strength (RSS). For evaluations, the authors implemented the proposed method on the elastic WLAN system testbed using Raspberry Pi for APs and conducted experiments for nine network topologies in two buildings at Okayama University. The results show that the proposal always selects the best power in any topology.