This paper proposes a robust beamforming (BF) scheme to enhance the physical layer security (PLS) of a multibeam satellite system operating at Ka band. By considering the effects of beam gain, path loss, and rain attenuation, we first formulate a constrained optimization problem to maximize the minimal achievable secrecy rate of multiuser under the assumption of imperfect eavesdropping channel and the constraint of total transmit power on the satellite. Since the problem is non-convex and mathematically intractable, we exploit the sequential convex approximation approach and S-procedure method to transform the original problem into one with a series of linear matrix inequality and second-order cone constraints, and then propose an iterative scheme to obtain the optimal BF weight vectors. Finally, simulation results showing the effectiveness and superiority of the proposed algorithm are provided.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported in part by the Key International Cooperation Research Project under Grant 61720106003, in part by the National Natural Science Foundation of China under Grants 61801234 and 61271255, in part by the Natural Science Foundation of Jiangsu Province under Grant BK20160911, and in part by the open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications), Ministry of Education No. JZNY201701. The review of this paper was coordinated by Prof. L. Wang.