Resource Allocations for Secure Cognitive Satellite-Terrestrial Networks

In this letter, we investigate the secure transmission in a cognitive satellite-terrestrial network with a multi-antennas eavesdropper, where the interference from terrestrial base station is introduced to enhance security of the satellite link. Our objective is to minimize the transmit power by jointly optimizing the cooperative beamforming and artificial noise while guaranteeing the secrecy rate constraint for satellite link, the information rate constraint for terrestrial link and the total transmit power constraint. Both scenarios of the perfect and imperfect channel cases are considered. The resulting optimization problems are non-convex and challenging, which are efficiently solved via certain transformations to be reformulated more tractable versions, respectively. Numerical results are provided to corroborate the proposed schemes.