An Enhanced Double Threshold Energy Detection in Cognitive Radio

摘要

Cognitive radio (CR) is regarded as a perfect technique to cope with the scarcity of spectrum resources. Energy detection is preferred by most of Cognitive Radio researchers, because it is easy to implement and it doesn't need the prior information about primary user's (PU) signals. But the performance of energy detection is poor at the low signal-to-noise ratio (SNR) regime. Double threshold spectrum sensing scheme was proposed to increase the reliability of decision. Under the same SNR, if the sensing time is not long enough, a higher noise variance will make the instance energy level falls below the threshold because of the noise uncertainty. In this paper, an enhanced energy detection (EED) scheme combined with double thresholds is proposed, this scheme can reduce the misdetection caused by noise uncertainty. In the proposed method, we compare the average of last M sensing statistic with the preset threshold. It aims at protecting a channel that are underutilizing from being decided to be idle when an immediate signal energy drop happens. The simulation makes a comparison between the proposed method and the traditional method and proves the effectiveness of the new scheme.