Secure performance analysis of cognitive two-way relay system with an eavesdropper

This paper investigates the system performance of two-way relay channel with an eavesdropper in cognitive network, where two users exchange their information via an assisting relay based on the detection results of the primary users. Specifically, when the two-way relay system detects that the primary users do not occupy the spectrum, they will perform the two-way transmission. Otherwise, they will keep silent. Besides, an eavesdropper tries its best to overhear the information from the two-way transmission. For such a system, its performance in terms of the intercept probability is derived over Rayleigh fading channels. Numerical results are provided to show the intercept performance of the system versus the system transmission power and data rate threshold.