Physical Layer Security of AF-Based Hybrid Satellite-Terrestrial Networks

This paper focuses on designing a relay beamformer to maximize a sum secrecy rate in hybrid satellite-terrestrial relay networks. The system employs an amplify-and-forward relay in an uplink multi-user scenario. To resolve the nonconvexity of the formulated optimization problem, slack variables are introduced, and first-order Taylor expansion is applied. The problem is then solved using successive convex approximation. Simulation results compare the sum secrecy rate of the proposed scheme with baselines.