Adaptive Sensing Technique to Maximize Spectrum Utilization in Cognitive Radio

A cognitive radio (CR) system exploits spectrum bands that primary users (PUs) are licensed to use. The CR performs channel sensing to find spectrum opportunities. Conventional periodic sensing schemes require a long sensing time to detect a weak signal from the PU with fast channel-usage variation. Since the CR network should be quiet during a sensing period, a long sensing time results in low spectrum utilization. To improve spectrum utilization, we propose a novel sensing scheme that adaptively decides whether to sense the channel or to transmit the user data based on previous sensing results. The simulation results show that the proposed scheme significantly outperforms the conventional scheme.