RIS-Enabled Integrated Sensing and Communications: From Theory to Practice

Reconfigurable intelligent surface (RIS)-assisted integrated sensing and communication (ISAC) is emerging as a key enabler for sixth-generation (6G) wireless systems, unifying communication, sensing, and control within a reconfigurable electromagnetic (EM) environment. This article presents a comprehensive review that integrates theoretical foundations, signal processing methodologies, and experimental implementations of RIS-ISAC. It first summarizes core principles of channel modeling, waveform design, and sensing parameter estimation across near-field, broadband, and multihop propagation regimes. Building on these foundations, the article surveys advances in hardware architectures, testbeds, and prototype demonstrations spanning sub-6 GHz to millimeter-wave and terahertz bands. Cross-cutting insights are drawn on system tradeoffs, performance bounds, and learning-aided adaptation. Finally, unified benchmarking metrics and open challenges are identified, covering synchronization, scalability, and standardization, to guide the evolution of RIS-ISAC from conceptual frameworks to practical 6G network deployments.