Secure RIS-Aided Multicasting: Globally Optimal Beam Management and Discrete-Phase RIS Configuration

2026-09-18

AI Summary

本文针对RIS辅助多播中的安全问题，包括离散相位、共谋窃听者和静态波束效率低下，通过优化RIS配置与基站波束管理，降低窃听信噪比，提高系统安全性。

Abstract

Reconfigurable intelligent surfaces (RISs) are poised to revolutionize wireless multicasting by enabling extended coverage and reliable operation in obstructed environments. These benefits, however, can be undermined by security vulnerabilities arising from practical deployment factors. This work addresses three such critical factors, (i) the discrete nature of RIS phase shifts, (ii) the presence of colluding eavesdroppers, and (iii) the inefficiency of static illumination beams, each threatening security if not properly accounted for in system design. To mitigate these issues, we formulate a joint resource allocation problem that minimizes the wiretap signal-to-noise ratio (SNR) across all eavesdroppers by co-optimizing the RIS configuration and the base station (BS) beam management. This yields a complex, nonconvex mixed-integer nonlinear program (MINLP), which we equivalently reformulate into a tractable mixed-integer quadratically constrained program (MIQCP) solvable to global optimality. Numerical results confirm that the proposed scheme significantly bolsters security, suppressing the wiretap SNR by up to 58% compared to existing baselines.

Problem

• Reconfigurable Intelligent Surfaces
• Wiretap Security
• Discrete-Phase Shifts
• Colluding Eavesdroppers
• Beam Management

Innovation

• Reconfigurable Intelligent Surfaces
• Joint Resource Allocation
• Mixed-Integer Quadratically Constrained Program
• Wiretap SNR
• Security