ABSTRACT

Dynamic spectrum allocation (DSA) solutions such as cognitive radio networks (CRNs) have been proposed as a key technology to exploit the frequency segments that are spectrally underutilized. In this paper, the performance of cooperative CRNs has been analyzed under two different operational modes, namely, constant primary user protection (CPUP) and constant secondary user spectrum usability (CSUSU). The CRN performance metrics have been selected to be the overall CRN capacity and the overall interference from CRN to the primary users under CPUP and CSUSU scenario, respectively. Computer simulations are invoked to evaluate the CRN performance with varying the sensing time as well as the number of cooperating users in the network and the observations have been presented. Finally, particle swarm optimization algorithm has been used to jointly optimize the sensing time duration and cooperation level of spectrum sensing in CRNs. The simulation results show that the CRN performance can be noticeably improved by applying suitable optimization algorithms.