Rate-Splitting Multiple Access for Intelligent Reflecting Surface-Aided Secure Transmission

TL;DR

This paper proposes a rate-splitting multiple access scheme combined with intelligent reflecting surfaces to enhance secure multi-user communication, optimizing beamforming and artificial noise to maximize the minimum secrecy rate with improved efficiency.

Contribution

It introduces a novel joint optimization framework for IRS-assisted secure communication using RSMA, demonstrating significant secrecy performance improvements over benchmarks.

Findings

Proposed algorithm effectively enhances the minimum secrecy rate.

RSMA reduces the number of IRS elements needed for target secrecy.

Significant performance gains over schemes without IRS or other multiple access methods.

Abstract

In this letter, we study a rate-splitting multiple access (RSMA)-based intelligent reflecting surface (IRS)-aided multi-user multiple-input single-output (MISO) secure communication system with a potential eavesdropper (Eve). Aiming to maximize the minimum secrecy rate (SR) among all the legitimate users (LUs), a design problem for jointly optimizing the transmit beamforming with artificial noise (AN), the IRS beamforming, and the secrecy common rate allocation is formulated. Since the design problem is highly non-convex with coupled optimization variables, we develop a computationally efficient algorithm based on the alternating optimization (AO) technique to solve it suboptimally. Numerical results demonstrate that the proposed design can significantly improve the max-min SR over the benchmark schemes without IRS or adopting other multiple access techniques. In particular, employing the RSMA strategy can substantially reduce the required numbers of IRS elements for achieving a target level of secrecy performance compared with the benchmark schemes.