Security analysis of relaying NOMA systems over Beaulieu–Xie fading channels with I/Q imbalance

Abstract

The paper studies the impact of in-phase and quadrature-phase imbalance (IQI) on the performance of cooperative non-orthogonal multiple access (NOMA) systems over Beaulieu–Xie fading channels. In the presence of an eavesdropper, the information is decoded-and-forward to the legitimate users at the relay, and the successful interference cancellation technology is utilized at the receiving end to eliminate the interference between the far and the near users. The closed-form expressions of outage probability (OP) and intercept probability (IP) are deduced to investigate the reliability and security. Moreover, the asymptotic expressions of OP for high signal-to-noise ratio are obtained. Finally, Monte Carlo simulations coincide perfectly with the results of theoretical derivation, which verifies the correctness of the analysis. The interesting results are that the presence of IQI reduces reliability but increases security. In addition, the increase of the target rate and the decrease of the channel parameter m can weaken the reliability.