Secrecy Performance Analysis of Cognitive Radio Networks with Full-duplex Relaying

Abstract

In this paper, we investigate the secrecy performance of cognitive radio networks (CRNs) with full-duplex (FD) relaying over Rayleigh channels, where the secondary transmitter (Alice) communicates with the secondary receiver (Bob) with the help of the FD relay in the presence of an eavesdropper (Eve). For secrecy performance enhancement, we propose two schemes at the FD relay, i.e., selection combining-zero forcing beamforming/maximal-ratio transmission (SC-ZFB/MRT) and SC-ZFB/ZFB. The closed-form and asymptotic expressions for the secrecy outage probability (SOP) and the secrecy throughput of the CRNs with SC-ZFB/MRT and SC-ZFB/ZFB schemes are derived, respectively. From the analysis, we demonstrate that: a) the proposed SC-ZFB/ZFB scheme can achieve better secrecy performance than that of the SC-ZFB/MRT scheme and b) when R S is fixed, the SC-ZFB/ZFB and SC-ZFB/MRT schemes always attain higher secrecy throughput than the previously proposed maximal-ratio combining (MRC)/MRT scheme.