RIS-Enabled Smart Wireless Environments: Fundamentals and Distributed Optimization
2025/12/21 by George C. Alexandropoulos, Kostantinos D. Katsanos, Alexandropoulos, George C. +5
Engineering · #Advanced MIMO Systems Optimization #Advanced Wireless Communication Technologies #FOS: Computer and information sciences #FOS: Electrical engineering #Information Theory (cs.IT) #Machine Learning (cs.LG) #Millimeter-Wave Propagation and Modeling #Signal Processing (eess.SP) #electronic engineering #information engineering
paper · doi:10.48550/arxiv.2512.18788
openalex publication_date 2025/12/21 · openalex created_date 2025/12/24 · openalex updated_date 2026/07/28
Abstract
This chapter overviews the concept of Smart Wireless Environments (SWEs) motivated by the emerging technology of Reconfigurable Intelligent Surfaces (RISs). The operating principles and state-of-the-art hardware architectures of programmable metasurfaces are first introduced. Subsequently, key performance objectives and use cases of RIS-enabled SWEs, including spectral and energy efficiency, physical-layer security, integrated sensing and communications, as well as the emerging paradigm of over-the-air computing, are discussed. Focusing on the recent trend of Beyond-Diagonal (BD) RISs, two distributed designs of respective SWEs are presented. The first deals with a multi-user Multiple-Input Single-Output (MISO) system operating within the area of influence of a SWE comprising multiple BD-RISs. A hybrid distributed and fusion machine learning framework based on multi-branch attention-based convolutional Neural Networks (NNs), NN parameter sharing, and neuroevolutionary training is presented, which enables online mapping of channel realizations to the BD-RIS configurations as well as the multi-user transmit precoder. Performance evaluation results showcase that the distributedly optimized RIS-enabled SWE achieves near-optimal sum-rate performance with low online computational complexity. The second design focuses on the wideband interference MISO broadcast channel, where each base station exclusively controls one BD-RIS to serve its assigned group of users. A cooperative optimization framework that jointly designs the base station transmit precoders as well as the tunable capacitances and switch matrices of all metasurfaces is presented. Numerical results demonstrating the superior sum-rate performance of the designed RIS-enabled SWE for multi-cell MISO networks over benchmark schemes, considering non-cooperative configuration and conventional diagonal metasurfaces, are presented.
Citations
- Over-the-Air Semantic Alignment with Stacked Intelligent Metasurfaces
- 2D Waveguide-Fed Metasurface Antenna Arrays: Modeling and Optimization for Bistatic Sensing
- MIMO Communications with 1-bit RIS: Asymptotic Analysis and Over-the-Air Channel Diagonalization
- Joint Active RIS Configuration and User Power Control for Localization: A Neuroevolution-Based Approach
- Electromagnetics-Compliant Optimization of Dynamic Metasurface Antennas for Bistatic Sensing
- Integrating Stacked Intelligent Metasurfaces and Power Control for Dynamic Edge Inference via Over-The-Air Neural Networks
- Receiving RISs: Enabling Channel Estimation and Autonomous Configuration
- Communications-Centric Secure ISAC with Hybrid Reconfigurable Intelligent Surfaces
- Tracking-Aided Multi-User MIMO Communications with Hybrid Reconfigurable Intelligent Surfaces
- Over-the-Air Edge Inference via End-to-End Metasurfaces-Integrated Artificial Neural Networks
- Active Reconfigurable Intelligent Surfaces: Circuit Modeling and Reflection Amplification Optimization
- Beyond Diagonal RIS in Multiuser MIMO: Graph Theoretic Modeling and Optimal Architectures with Low Complexity
- Extremely Large Full Duplex MIMO for Simultaneous Downlink Communications and Monostatic Sensing at Sub-THz Frequencies
- Lightweight Security for Ambient-Powered Programmable Reflections with Reconfigurable Intelligent Surfaces
- Metasurfaces-Enabled Wave Computing for Future Wireless Systems: Opportunities and Challenges
- Characterization of Indoor RIS-Assisted Channels at 304 GHz: Experimental Measurements, Challenges, and Future Directions
- On the Detection of Non-Cooperative RISs: Scan B-Testing via Deep Support Vector Data Description
- Simultaneous Communications and Sensing with Hybrid Reconfigurable Intelligent Surfaces
- MIMO MAC Empowered by Reconfigurable Intelligent Surfaces: Capacity Region and Large System Analysis
- Stacked Intelligent Metasurfaces for Task-Oriented Semantic Communications
- Metasurface Energy Harvesters: State-of-the-Art Designs and Their Potential for Energy Sustainable Reconfigurable Intelligent Surfaces
- Multi-RIS-Empowered Multiple Access: A Distributed Sum-Rate Maximization Approach
- Near-Field Beam Tracking with Extremely Large Dynamic Metasurface Antennas
- Beyond Diagonal Reconfigurable Intelligent Surfaces in Wideband OFDM Communications: Circuit-Based Modeling and Optimization
- Wideband Channel Capacity Maximization With Beyond Diagonal RIS Reflection Matrices
- Evasive Active Hypothesis Testing with Deep Neuroevolution: The Single- and Multi-Agent Cases
- Two-Dimensional Direction-of-Arrival Estimation Using Stacked Intelligent Metasurfaces
- 1-Bit SubTHz RIS with Planar Tightly Coupled Dipoles: Beam Shaping and Prototypes
- Spatial Secrecy Spectral Efficiency Optimization Enabled by Reconfigurable Intelligent Surfaces
- Stacked Intelligent Metasurfaces for Efficient Holographic MIMO Communications in 6G
- On the Impact of Control Signaling in RIS-Empowered Wireless Communications
- Performance of RIS-Aided Nearfield Localization under Beams Approximation from Real Hardware Characterization
- RIS-Enabled Smart Wireless Environments: Deployment Scenarios, Network Architecture, Bandwidth and Area of Influence
- On the Tacit Linearity Assumption in Common Cascaded Models of RIS-Parametrized Wireless Channels
- STAR-RIS-Enabled Simultaneous Indoor and Outdoor 3D Localization: Theoretical Analysis and Algorithmic Design
- RISs and Sidelink Communications in Smart Cities: The Key to Seamless Localization and Sensing
- RIS-Enabled and Access-Point-Free Simultaneous Radio Localization and Mapping
- RIS-Aided Monostatic Sensing and Object Detection with Single and Double Bounce Multipath
- 3D Localization with a Single Partially-Connected Receiving RIS: Positioning Error Analysis and Algorithmic Design
- Counteracting Eavesdropper Attacks Through Reconfigurable Intelligent Surfaces: A New Threat Model and Secrecy Rate Optimization
- Reconfigurable Intelligent Surfaces and Capacity Optimization: A Large System Analysis
- Integrated Sensing and Communication with Reconfigurable Intelligent Surfaces: Opportunities, Applications, and Future Directions
- Pervasive Machine Learning for Smart Radio Environments Enabled by Reconfigurable Intelligent Surfaces
- Beyond Diagonal Reconfigurable Intelligent Surfaces: From Transmitting and Reflecting Modes to Single-, Group-, and Fully-Connected Architectures
- Online RIS Configuration Learning for Arbitrary Large Numbers of 1-Bit Phase Resolution Elements
- Massive Access of Static and Mobile Users via Reconfigurable Intelligent Surfaces: Protocol Design and Performance Analysis
- Near-Field Hierarchical Beam Management for RIS-Enabled Millimeter Wave Multi-Antenna Systems
- Wideband Multi-User MIMO Communications with Frequency Selective RISs: Element Response Modeling and Sum-Rate Maximization
- Non-Coherent MIMO-OFDM Uplink empowered by the Spatial Diversity in Reflecting Surfaces
- Low-to-Zero-Overhead IRS Reconfiguration: Decoupling Illumination and Channel Estimation
- Channel Estimation with Reconfigurable Intelligent Surfaces -- A General Framework
- Reconfigurable, Intelligent, and SustainableWireless Environments for 6G Smart Connectivity
- PyGAD: An Intuitive Genetic Algorithm Python Library
- Autonomous Reconfigurable Intelligent Surfaces Through Wireless Energy Harvesting
- Wireless Environment as a Service Enabled by Reconfigurable Intelligent Surfaces: The RISE-6G Perspective
- Hybrid Reconfigurable Intelligent Metasurfaces: Enabling Simultaneous Tunable Reflections and Sensing for 6G Wireless Communications
- Active Reconfigurable Intelligent Surface Aided Wireless Communications
- Phase Configuration Learning in Wireless Networks with Multiple\n Reconfigurable Intelligent Surfaces
- Beyond Intelligent Reflecting Surfaces: Reflective-Transmissive Metasurface Aided Communications for Full-dimensional Coverage Extension
- Reconfigurable Intelligent Surfaces with Reflection Pattern Modulation: Beamforming Design and Performance Analysis
- Reconfigurable Intelligent Surfaces: Principles and Opportunities
- Intelligent Reflecting Surface Aided Wireless Communications: A Tutorial
- Dynamic Metasurface Antennas for 6G Extreme Massive MIMO Communications
- Safeguarding MIMO Communications with Reconfigurable Metasurfaces and Artificial Noise
- A Hardware Architecture for Reconfigurable Intelligent Surfaces with Minimal Active Elements for Explicit Channel Estimation
- Intelligent Reflecting Surface: Practical Phase Shift Model and Beamforming Optimization
- Indoor Signal Focusing with Deep Learning Designed Reconfigurable Intelligent Surfaces
- Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming
- Attention Is All You Need
- Evolution Strategies as a Scalable Alternative to Reinforcement Learning
- Asynchronous Methods for Deep Reinforcement Learning
- Neural Machine Translation by Jointly Learning to Align and Translate
- Reconfigurable Intelligent Computational Surfaces: When Wave Propagation Control Meets Computing
Related