Unlicensed Spectrum Usage Method for Cellular Communication Systems

Cellular systems operate on ISM band with the co-existence of wide-deployed WLAN is a promising solution to offload the crowded cellular band, where cellular device acting as virtual a WLAN station contends for WLAN channel resource via applying the same IEEE 802.11 Distributed Coordination Function(DCF) as WLAN rivals is a straightforward way. However, the conventional mechanism cannot fully utilize the spectrum resource, we propose an adaptive probability access (APA) method which could adjust the channel access probability of cellular system by maximizing the proportional fairness throughput of both systems. This method can adjust the cellular access probability step by step to ensure that both cellular and WLAN work near the optimum operating spot. Simulation results show that the proposed APA method improves both the proportional fairness and total throughput.