On convergence of a distributed cooperative spectrum sensing procedure in cognitive radio networks

In this work, we analyze a distributed cooperative spectrum sensing scheme where N secondary users (SUs) of a cognitive wireless network try to agree about the primary user presence (absence) by iterative interchanging individual opinions (states) over an unreliable wireless propagation medium. It is assumed that the SUs update their personal states based on the “K-out-of-N” rule, and the interchange session fails, if the consensus has not been reached within a fixed number of iterations. The problem of forming a joint opinion becomes challenging because a SU makes its personal decision based on local observations distorted by a wireless propagation medium. This fact may cause a disorder. In this paper, we formulate sufficient conditions of reaching the agreement on the basis of local observations.