Improving Secrecy Performance of Land Mobile Satellite Systems via a UAV Friendly Jammer

Land mobile satellite (LMS) systems and unmanned aerial vehicles (UAVs) are the key enablers for broadband wireless networks to serve terrestrial mobile users over a broad area with low cost. However, with the increasing dependency on the aerospace communication infrastructure, the wiretapping and security threats would be a major concern. In this paper, we investigate the secrecy performance of a downlink LMS system by employing a UAV-based friendly jammer in the presence of an eavesdropper on the ground. Specifically, we derive the secrecy outage probability (SOP) of the considered LMS system under the pertinent heterogeneous channels for the satellite links and the air-to-ground jammer. We further derive an asymptotic SOP expression to gain more insights into the system performance. Our theoretical results are validated through simulations and they reveal the impact of UAV position and other key parameters on the secrecy performance of LMS systems.