On the cluster size of cognitive radio networks

In opportunistic model of cognitive radio(CR) networks, secondary users(SUs) are allowed to access the licensed band provided they do not interfere with the primary users(PUs). To ensure this, SUs have to perform spectrum sensing to locate the spectrum holes. The performance of spectrum sensing is improved through cooperation among spatially distributed SUs in a clustered network. In this paper, we are proposing an algorithm to find the optimal radius, R of the clustered network to limit the number of SUs participating in cooperative spectrum sensing which would therefore also reduce the burden on band limited control channel. We have found the optimal value of R for single threshold energy detection method to be 1.1235 km and for double threshold energy detection to be 0.5476 km.