Physical layer security of interference-limited land mobile satellite communication systems

In this paper, we investigate the secrecy performance of a downlink land mobile satellite (LMS) system, where a satellite transmits signal to a legitimate user in the presence of an eavesdropper at the ground. Herein, we consider that co-channel interference signals are present at the user destination node. By leveraging the statistics of underlying Shadowed-Rician fading channels for satellite links and Nakagami-m fading for interfering terrestrial links, we derive an accurate expression for secrecy outage probability (SOP) of the considered LMS system. To gain more insights, we derive an asymptotic expression for SOP at high signal-to-noise ratio regime and illustrate that system can attain a unity diversity order even under the influence of interferers. Subsequently, we also deduce the expression for probability of non-zero secrecy capacity. The analytical results are validated through Monte-Carlo simulations and utilized to reveal the impact of various key channel/system parameters in understanding the physical layer security aspects of LMS system.