Advanced Multibeam Satellite Network Security with Encryption and Beamforming Technologies

For B5G/6G networks, security will be a critical issue due to data explosion from the launch of non-terrestrial net-works (NTN) and space-terrestrial integrated networks (STIN). To this end, encryption and physical layer security (PLS) on top of the NTN or STIN have been studied extensively. However, a use of either encryption or PLS only has critical drawbacks: the encryption induces an additional power or time cost, while the performance of PLS can be limited by the capability of eavesdroppers (Eves). In this paper, we propose a multibeam satellite network security solution by exploiting encryption and beamforming technologies. Satellites are assumed to be capable of transmitting two types of encrypted and non-encrypted signals for broadcast and private messages, simultaneously. We first design a security threat under non-colluding and colluding eavesdropping attacks. Thereafter, we explore power allocation, user selection, and beam scheduling based on security threats and channel conditions over satellite downlinks in orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) systems, respectively. We show the improved secrecy performance of the proposed method compared to the secrecy capacity of PLS. Finally, the simulation results demonstrate that NOMA has better total capacity and secrecy performances than OMA.