Physical-Layer Security for Cognitive Radio Networks over Cascaded Rayleigh Fading Channels

In this paper, physical-layer security (PLS) for an underlay cognitive radio network (CRN) over cascaded Rayleigh fading channels is studied. The underlying cognitive radio system consists of a secondary source transmitting to a destination over a cascaded Rayleigh fading channel. An eavesdropper is attempting to intercept the confidential information of the secondary users (SUs) pair. The secrecy is studied in terms of three main security metrics, which are the secrecy outage probability (SOP), the probability of non-zero secrecy capacity (P
_rnzc
), and the intercept probability (Pint). The effects of the path loss and the variation of the distances from the SU transmitter over the secrecy are also analyzed. Results reveal the great effect of the cascade level over the system secrecy. In addition, the effect of varying the interference threshold that the PU receiver can tolerate over the secrecy of the SUs pair is studied. The effect of the channel model parameters of both the main and the wiretap channels is investigated using both simulation and analytical results.