Robust Beamforming for Practical RIS-Aided RSMA Systems with Imperfect SIC under Transceiver Hardware Impairments

2026-03-19

AI Summary

This work addresses the performance degradation in practical reconfigurable intelligent surface (RIS)-assisted rate-splitting multiple access (RSMA) systems caused by transceiver hardware impairments, RIS amplitude–phase coupling, and imperfect successive interference cancellation (SIC). For the first time, these non-idealities are jointly modeled to derive closed-form expressions for distortion noise and formulate a robust sum-rate maximization framework. The resulting non-convex problem is efficiently solved via asymptotic signal-to-noise ratio analysis combined with a block variable relaxation algorithm. The proposed scheme maintains high sum-rate and strong robustness under various practical impairments, significantly outperforming conventional non-orthogonal multiple access (NOMA) schemes.

Technology Category

• Intelligent Robots: Multi-Robot Systems
• Search and Optimization: Non-convex Optimization
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Search and Retrieval-Augmented AI: Assisted, interactive, and conversational search
• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications

Abstract

Reconfigurable intelligent surface (RIS)-aided rate-splitting multiple access (RSMA) systems have demonstrated remarkable potential in enhancing spectral efficiency. However, most existing works rely on ideal hardware, which is unrealistic.In practical deployments, RIS elements suffer from amplitude-phase coupling, where transceivers are subject to hardware impairments (HWI), and successive interference cancellation (SIC) in RSMA networks cannot achieve perfect interference elimination for decoded signals.To address these limitations, we investigate a robust beamforming design for RIS-aided RSMA systems under practical hardware imperfections. We first characterize the asymptotic signal-to-noise ratio (SNR) of practical RIS systems when the beamformer is designed based on ideal RIS model, thereby theoretically quantifying the resulting performance degradation. We then derive a closed-form expression for the distortion noise power induced by transceiver HWI, while also accounting for residual interference due to imperfect SIC. Building on these insights, we establish a comprehensive system model that jointly incorporates all hardware-induced impairments and formulate a multiuser sum rate maximization problem. To solve the resulting non-convex optimization problem, we develop an efficient block variable relaxation algorithm. Simulation results verify that the proposed scheme significantly outperforms conventional non-orthogonal multiple access (NOMA) approaches, and achieves superior robustness compared with benchmark schemes neglecting HWI, imperfect SIC, or amplitude-phase coupling.

Problem

• Reconfigurable Intelligent Surface (RIS)
• Rate-Splitting Multiple Access (RSMA)
• Hardware Impairments (HWI)
• Imperfect SIC
• Amplitude-Phase Coupling

Innovation

• RIS-aided RSMA
• hardware impairments
• imperfect SIC
• amplitude-phase coupling
• robust beamforming