Sensing strategies for channel discovery in Cognitive Radio Networks

We consider spectrum sensing strategies used to discover available spectrum in Cognitive Radio Networks (CRNs), using both non-cooperative sensing and cooperative sensing approaches. After introducing the background to sensing techniques, this position paper focuses on strategies and algorithms for conducting sensing such that the sensing time and energy are minimized, and the likelihood of finding available spectrum is maximized. The paper mainly focuses on two approaches. The first is the ordering of channels to be sensed, and the second is cooperative spectrum sensing. After discussing the available strategies under each of these two approaches, we introduce our own proposed approaches. We first introduce a method for sorting the channels to be sensed in order to optimize the sensing time, while satisfying PUs´ protection and false alarm constraints. Then, we introduce a framework for cooperative sensing of multiple PUs´ channels by a group of SUs. The framework includes strategies for assigning different SUs to sense different PUs´ channels, selection of the fusion center for each of the SUs clusters, and routing sensing data within the cluster from the SUs to the fusion center. We show how this framework is capable of optimizing different objective functions. Several open problems and future research directions are also introduced.