Joint Beamforming and Jamming Design for Secure Cooperative Hybrid Satellite-Terrestrial Relay Network

This paper investigates the secure transmit design of a cooperative hybrid satellite-terrestrial relay network (HSTRN). Assuming that amplify-and-forward (AF) protocol is adapted at terrestrial relays, and global channel state information (CSI) is known, we propose two schemes through jointly optimizing the relay beamforming vector and the covariance matrix of artificial noise (AN) to maximize the secrecy rate. In the first scheme, our design is based on secrecy rate maximization and optimal solution is obtained by following the idea of two-level optimization which is composed of one-dimensional search technique and semidefinite relaxation (SDR) technique. In the second scheme, to reduce the computation, we assume that there is no information leakage to all eavesdroppers, and the solution of this problem is obtained by solving one semidefinite programing (SDP) only with SDR. Numerical results are provided to demonstrate the performance of different designs and the benefit of AN.