Next-Generation Security for LEO Satellite Communication: Sub-THz Frequency Paradigm

The increasing demand in data rates and new emerging applications require that the future generation of satellite networks will be designed at sub-THz frequencies with ultra-broad bandwidth. Such next generation communication network owing to its own complexity will be prone to cyberattacks. In this study, we design a physical layer security for the next generation LEO satellite link. We consider a scenario where Eve is placed at a certain distance from the legitimate ground station (Bob) while communicating with low-earth orbit (LEO) satellite (Alice). By taking advantage of the uniqueness of THz atmospheric channel, we derive a closed form expression of the optimum power spectral density (PSD) of the transmitted signal so as to maximize the channel capacity. By leveraging the higher losses due to atmospheric channel and optimum PSD, we improve the physical layer security of the satellite link in the considered scenario. The simulation results show that we can enhance the normalized secrecy capacity beyond a small coverage area near the legitimate receiver Bob.