Robust Consensus-Based Distributed Beamforming for Wideband Cell-free Multi-RIS MISO Systems

2026-01-13

AI Summary

This work addresses the high coordination overhead and poor robustness of centralized beamforming in wideband cell-free multi-RIS-assisted MISO systems, which arise from imperfect channel state information and the frequency-selective response of reconfigurable intelligent surfaces (RISs). To overcome these challenges, the paper proposes a consensus-based distributed framework for joint active and passive beamforming. For the first time, consensus optimization is introduced into wideband multi-RIS cell-free systems, enabling distributed and robust phase control of RISs without requiring a central processing unit. The approach integrates Lorentzian-based RIS modeling with imperfect channel information handling to ensure practical feasibility. Simulation results demonstrate that the proposed method significantly reduces coordination overhead, enhances system robustness, and outperforms existing Lorentzian-model-based centralized schemes in terms of overall performance.

Technology Category

• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Distributed Search
• Intelligent Robots: Learning & Optimization for ROB

Application Category

• Responsible Web: Consent frameworks and practices on the web
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation

Abstract

The cell-free networking paradigm constitutes a revolutionary architecture for future generations of wireless networks, which has been recently considered in synergy with Reconfigurable Intelligent Surfaces (RISs), a promising physical-layer technology for signal propagation programmability. In this paper, we focus on wideband cell-free multi-RIS-empowered Multiple-Input Single-Output (MISO) systems and present a decentralized cooperative active and passive beamforming scheme, aiming to provide an efficient alternative towards the cooperation overhead of available centralized schemes depending on central processing unit. Considering imperfect channel information availability and realistic frequency selectivity behavior of each RIS's element response, we devise a distributed optimization approach based on consensus updates for the RISs'phase configurations. Our simulation results showcase that the proposed distributed design is superior to centralized schemes that are based on various Lorentzian-type wideband modeling approaches for the RISs.

Problem

• Cell-free
• Reconfigurable Intelligent Surfaces
• Distributed Beamforming
• Wideband MISO
• Imperfect Channel State Information

Innovation

• Distributed Beamforming
• Consensus-Based Optimization
• Reconfigurable Intelligent Surfaces (RIS)
• Wideband Cell-Free MISO
• Frequency-Selective RIS