Multiple systems sensing for cognitive radio networks over Rayleigh fading channel

Cognitive radios (CRs) with capability of spectrum sensing to fully utilize radio spectrum have been considered as a key technology toward future wireless communications. We can further leverage CRs to form cognitive radio networks (CRNs). When we consider sensing for CRNs, it is critical to identify the potential primary and secondary systems for construction of time-varying CRNs. In this paper we propose a general sensing algorithm to sense the spectrum usage and identify active systems under a multiple-systems coexisting environment over Rayleigh fading channel. We exploit unique characteristics of systems consisting of fundamental frequency, power spectrum density and four-order cumulant to accomplish the multiple systems sensing. Our algorithm can also be applied by Detect and Avoid (DAA) for UWB with a priori knowledge of system parameters in active systems.