Ris-Assisted Physical Layer Security in Leo Satellite Communications

As terrestrial networks face limitations in delivering global wireless communications, the shift towards non-terrestrial networks, particularly satellite-based systems, becomes increasingly essential for connecting remote regions. However, these networks are susceptible to security risks, such as eavesdropping, making the assurance of physical layer security (PLS) critical to achieving secure global wireless connectivity. Emerging technologies like reconfigurable intelligent surfaces (RISs) and higher frequency bands, such as the THz range, offer promising solutions for enhancing the PLS. This paper investigates the secrecy performance of a RIS-assisted satellite communication system operating in the THz band. We derive expressions for key security metrics, including the secrecy outage probability (SOP), lower bound SOP, and intercept probability (IP). Furthermore, in a practical scenario, we analyze the effect of misalignment and solar scintillation on reliable satellite communication. Simulation results validate the analytical findings, highlighting the importance of utilizing RIS in improving secrecy performance.