Enhancing Physical Layer Security in Cognitive Radio-Enabled NTNs with Beyond Diagonal RIS

2025-03-20

AI Summary

This work addresses physical-layer security in cognitive radio-enabled space-air-ground integrated multi-layer non-terrestrial networks (NTNs), specifically under coexistence of a high-altitude platform station (HAPS) primary network and an unmanned aerial vehicle (UAV) secondary network. Method: We propose the first joint optimization framework incorporating a beyond-diagonal reconfigurable intelligent surface (BD-RIS) into this setting, jointly designing BD-RIS phase shifts and secondary link power allocation to maximize the secondary link’s secrecy rate while respecting the primary network’s interference temperature constraint. The approach integrates BD-RIS-enabled channel reconstruction, cognitive spectrum sharing modeling, and an alternating optimization algorithm. Contribution/Results: Simulation results demonstrate that the proposed scheme significantly enhances secrecy rate and maintains robust secure communication even under stringent interference constraints, establishing a novel paradigm for cross-layer interference management and physical-layer security co-design in NTNs.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Non-convex Optimization
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Applications of cryptography
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Location- and context-aware Web and WoT applications and services

Abstract

Beyond diagonal reconfigurable intelligent surfaces (BD-RIS) have emerged as a transformative technology for enhancing wireless communication by intelligently manipulating the propagation environment. This paper explores the potential of BD-RIS in improving cognitive radio enabled multilayer non-terrestrial networks (NTNs). It is assumed that a high-altitude platform station (HAPS) has set up the primary network, while an uncrewed aerial vehicle (UAV) establishes the secondary network in the HAPS footprint. We formulate a joint optimization problem to maximize the secrecy rate by optimizing BD-RIS phase shifts and the secondary transmitter power allocation while controlling the interference temperature from the secondary network to the primary network. To solve this problem efficiently, we decouple the original problem into two sub-problems, which are solved iteratively by relying on alternating optimization. Simulation results demonstrate the effectiveness of BD-RIS in cognitive radio-enabled multilayer NTNs to accommodate the secondary network while satisfying the constraints imposed from the primary network.

Problem

• Enhance physical layer security in cognitive radio-enabled NTNs.
• Optimize BD-RIS phase shifts and secondary transmitter power allocation.
• Control interference temperature from secondary to primary networks.

Innovation

• BD-RIS enhances wireless communication security.
• Optimizes BD-RIS phase shifts and power allocation.
• Uses alternating optimization for efficient problem-solving.