Channel-usage model in underlay cognitive radio networks

Abstract

In underlay cognitive radio networks (CRNs), a licensed channel can be shared with its primary users (PUs), provided the resultant interference power level at the primary receiver is below a predefined threshold, known as interference power constraint (IPC). Therefore, in such a scenario secondary users (SUs) have to perform the following - (a) perform spectrum sensing to detect the existence of PUs and (b) estimate the IPC to protect the PU from harmful interference. In this paper we develop a channel-usage model of PU's in underlay mode of CRNs using a Hidden Markov Model (HMM) that allows SU to predict the unused/usable spectra. The model estimates the interference power level of a license channel due to the presence of SUs and decides on the availability of the channel for SU's transmission imposing IPC. Further, a channel selection scheme is developed so that SUs can decide and select the best channel in the presence of multiple available licensed channels. Simulation results demonstrate the efficacy of the proposed model and its usability in underlay CRN. © 2013 Springer Science+Business Media.