Dynamic Channel Sensing Management for OFDMA-Based Cognitive Radio Systems

In the cognitive radio (CR) systems, channel sensing policy to detect the presence of primary user directly affects the quality-of-service (QoS) of both primary and CR users. In this paper, we investigate the efficient channel sensing scheme for the orthogonal frequency division multiple access (OFDMA) based CR systems. To improve the overall system performance, the proposed scheme exploits the multiuser-diversity in the frequency-selective fading channel, considering various types of the primary users. Performance of the proposed scheme is evaluated by simulation. Numerical results show that the proposed scheme can increase the utilization of the CR system while reducing the waiting time of the primary user.