Secrecy performance analysis over cascaded fading channels

Abstract

In this study, the authors investigate the secrecy performance at the physical layer of wireless communication systems where the channels are modelled as cascaded fading channels, in which the fading effects are worse than those in the cellular communication channels like Rayleigh and Nakagami-m. Analytic results are derived for the cascaded Nakagami-m fading channel model comprising the cascaded Rayleigh, 2*Nakagami-m, the generalised-K, and the conventional cellular channel models as well. By evaluating the information-theoretic physical layer security performance, they obtain the closed-form expressions of the average secrecy capacity and probability of the positive secrecy capacity in case of that channel-stateinformation of the eavesdropper is known by the source. Then they obtain the exact closed-form secrecy outage probability (SOP) when the eavesdropper is passive. Analytic results are computed in terms of the bivariate and univariate Meijer's G functions and later on are successfully validated through Monte Carlo simulations. The simulation results show that the secrecy performance worsens with the increasing cascading degree of the fading channels. For example, in 2*Nakagami-m fading channels where the cascading degree is 2, extra 4 dB signal-to-noise ratio is required to achieve the same SOP value in comparison with the classical Nakagami-m fading channels.