Twice Cooperative Spectrum Sensing in Cognitive Radio Networks

In cognitive radio network (CRN), traditional energy detection algorithm has a bad detection performance in fading and shadowing environment. So cooperative spectrum sensing among cognitive radio nodes is needed in order to overcome these drawbacks. However it will result in a large demand of communication bandwidth on the control channel when the number of the nodes is great. To this problem, this paper proposes a twice cooperative spectrum sensing scheme. In this scheme, all secondary users are grouped into multiple clusters. Double threshold cooperative sensing algorithm and hard fusion ruling are adopted respectively in each cluster and fusion centre. By adopting this scheme, the number of bits transmitted to the fusion centre for decision result will be decreased. The simulation result shows that the proposed scheme can improve the detection performance.