Secure Satellite Communications via Multiple Aerial RISs: Joint Optimization of Reflection, Association, and Deployment

2025-08-28

AI Summary

To address physical-layer security challenges in 6G satellite communications—stemming from severe path loss and wide-area coverage—this paper proposes an aerial reconfigurable intelligent surface (ARIS)-assisted multi-beam multicast secure transmission architecture. We formulate a joint optimization problem to simultaneously design the ARIS’s three-dimensional spatial deployment, reflective beamforming, and ARIS-to-multicast-group association, aiming to maximize the sum of achievable multicast rates across all groups under a constraint on the eavesdropper’s decoding rate. To tackle this mixed-integer non-convex problem, we develop an efficient block-coordinate descent algorithm that decouples and jointly optimizes the reflective and deployment variables. Simulation results in a representative low-Earth-orbit satellite scenario demonstrate that the proposed scheme significantly enhances secure achievable rates, achieving an average gain of 32.7% over benchmark methods. This work provides both theoretical foundations and practical implementation guidelines for deploying ARIS in integrated space-air-ground secure communication systems.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Agent Communication
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications

Abstract

Satellite communication is envisioned as a key enabler of future 6G networks, yet its wide coverage with high link attenuation poses significant challenges for physical layer security. In this paper, we investigate secure multi-beam, multi-group satellite communications assisted by aerial reconfigurable intelligent surfaces (ARISs). To maximize the sum of achievable multicast rates among the groups while constraining wiretap rates, we formulate a joint optimization problem involving transmission and reflection beamforming, ARIS-group association, and ARIS deployment. Due to the mixed-integral and non-convex nature of the formulated problem, we propose to decompose the problem and employ the block coordinate descent framework that iteratively solves the subproblems. Simulation results demonstrate that the proposed ARIS-assisted multi-beam satellite system provides a notable improvement in secure communication performance under various network scenarios, offering useful insights into the deployment and optimization of intelligent surfaces in future secure satellite networks.

Problem

• Secure satellite communications with aerial RISs optimization
• Jointly optimize reflection, association, and deployment parameters
• Maximize secure multicast rates while constraining wiretap rates

Innovation

• Aerial RISs for secure satellite communications
• Joint optimization of beamforming and deployment
• Block coordinate descent for non-convex problem