A Practical Validation of RIS Detection and Identification
Recep Vural, Aymen Khaleel, Ertugrul Basar
TL;DR
This work addresses the challenge of identifying reachable RISs in RIS-assisted communications by introducing a phase-aware, amplitude-modulation scheme that maps RIS IDs to amplitude reflection patterns (ARP). The UE emits an unmodulated carrier while RISs modulate the reflected signal according to ARP symbols; a correlation-based detector over circularly shifted ARPs detects reachability, using a Walsh–Hadamard code subset to maintain orthogonality in asynchronous settings. The approach is validated experimentally with a 76-element RIS and SDR hardware across scenarios where RIS 1 is reachable, both RISs are reachable, or none are reachable, reporting false-alarm and miss-detection metrics and showing robustness to synchronization offsets. The results demonstrate practical RIS-ID capability and provide insights into how Tx gain and ARP length $M$ influence detection performance, with implications for deploying RIS-ID alongside beamforming and localization in future networks.
Abstract
Reconfigurable intelligent surface (RIS)-assisted communication is a key enabling technology for next-generation wireless communication networks, allowing for the reshaping of wireless channels without requiring traditional radio frequency (RF) active components. While their passive nature makes RISs highly attractive, it also presents a challenge: RISs cannot actively identify themselves to user equipments (UEs). Recently, a new method has been proposed to detect and identify RISs by letting them modulate their identities in the signals reflected from their surfaces. In this letter, we first propose a new and simpler modulation method for RISs and then validate the concept of RIS detection and identification (RIS-ID) using a real-world experimental setup. The obtained results validate the RIS-ID concept and show the effectiveness of our proposed modulation method over different operating scenarios and systems settings.