A novel cooperative spectrum sensing scheme based on clustering and softened hard combination

In cognitive radio systems, secondary users can be coordinated to perform cooperative spectrum sensing so as to detect the primary user more accurately. However, the conventional cooperative scheme does not explore the received energy information sufficiently. Thus, in this paper, we investigate the softened two-bit hard combination and clustering cooperative sensing schemes. Encouraged by the performance gain of soft combination, we propose a novel cooperative spectrum sensing scheme by combing the merits of these two schemes. Moreover, for some practical environments, a modification based on SNR estimation to the proposed scheme is made. Numerical results show that the sensing performance of the proposed scheme is improved significantly as opposed to other schemes. And it also achieves a good tradeoff between performance and complexity.