Low-dimensional Beamforming Design in Secure Satellite Communications

Recently, physical layer security (PHY-SEC) has been investigated for wireless communications to prevent eavesdropping without upper layer data encryption. This paper studies multibeam satellite secure communications with beamforming technologies. The design objective is to minimize the total transmit power of the satellite, while satisfying the individual secrecy rate constraint for each user. We propose a transmit power minimization (TPM) beamforming scheme aiming to minimize the transmit power. In order to reduce the complexity of the TPM beamforming design, a low-dimensional scheme has been proposed at the expense of the degraded performance. Simulation results demonstrate the efficiency of the TPM beamforming design and the acceptable performance degradation of the low-dimensional scheme.