Abstract: Without modifying the current IEEE 802.11 protocol, a novel heuristic algorithm based on proportional fairness optimization of Channel Assignment and Power Control is proposed to improve the performance of largescale wireless local area networks (WLANs), maximizing the effective bandwidth, while ensuring the fairness for each user to access the WLAN. Based on the traffic characteristic analysis from real network, we take both uplink and downlink traffic into account in the process of network modeling. The analysis towards network utility shows that it has a controllable upper bound. This characteristic helps us develop a strategy to improve network utility by maximizing the upper bound, and then forcing network utility approximate to the enhanced upper limit. In particular, both channel assignment (CA) and power control (PC) are performed in each iteration of the proposed algorithm. Extensive simulations show that the proposed algorithm outperforms current popular onedimensional optimization algorithms LCCS/PCAP, and compared the results in the aspect of increasing throughput, it reduces network delay.

Key words: WLAN, proportional fairness, power control, channel assignment