Enhancing Physical Layer Security in RIS-Aided HAPS for Non-Terrestrial Networks
Hanieh Memarian, S. Mohammad Razavizadeh, Ali Kuhestani · IEEE Access · 2025
This paper presents a novel approach to secure communication by integrating Reconfigurable Intelligent Surfaces (RIS) with High Altitude Platforms (HAPs) within the framework of Non-Terrestrial Networks (NTN) to protect against Aerial Eavesdroppers (AEve). This study addresses critical optimization challenges in enhancing the instantaneous secrecy rate within this innovative framework. By employing fractional programming, we effectively decompose the optimization problem for beamforming, enabling a robust solution that significantly improves security performance. Our model provides conservative estimates and advances the theoretical understanding of security in RIS-assisted HAP communications, which are essential components of future NTN architectures aimed at achieving seamless global connectivity. Simulation results demonstrate that our algorithm converges rapidly and outperforms conventional schemes that do not utilize RIS or employ random phases, achieving substantial improvements in secrecy rates. This research marks a significant advancement in addressing security vulnerabilities in next-generation wireless networks, laying the groundwork for future investigations into secure NTN-enabled RIS-HAP systems.