Physical-layer secrecy outage of spectrum sharing CR systems over fading channels

In this paper, we investigate the physical-layer secrecy outage performance of underlay spectrum sharing systems over Rayleigh and log-normal fading channels in the presence of one eavesdropper. In particular, the secondary transmitter sends data to the legitimate receiver under the constraints of the interference temperature at the primary receiver, while suffering the wiretap from the eavesdropper. Closed-form and approximated expressions are derived for the secrecy outage probability over Rayleigh and log-normal fading channels, respectively. The accuracy of our performance analysis is verified by simulation results.