Integrated Localization, Mapping, and Communication through VCSEL-Based Light-emitting RIS (LeRIS)

This paper presents a light-emitting reconfigurable intelligent surface (LeRIS) architecture that integrates vertical cavity surface emitting lasers (VCSELs) to jointly support user localization, obstacle-aware mapping, and millimeter-wave (mmWave) communication in programmable wireless environments (PWEs). Unlike prior light-emitting diode (LED)-based LeRIS designs with diffuse emission or LiDAR-assisted schemes requiring bulky sensing modules, the proposed VCSEL-based approach exploits narrow Gaussian beams and multimode diversity to enable compact, low-power, and analytically tractable integration. We derive closed-form expressions to jointly recover user position and orientation from received signal strength using only five VCSELs, and reduce this requirement to three under specific geometric conditions by leveraging dual-mode operation. In parallel, we introduce a VCSEL-based mapping method that uses reflected signal time-of-arrival measurements to detect obstructions and guide blockage-resilient RIS beam routing. Simulation results demonstrate millimeter-level localization accuracy, robust obstacle detection, high spectral efficiency, and substantial gains in minimum user rate. These findings establish VCSEL-based LeRIS as a scalable and practically integrable enabler for resilient 6G wireless systems with multi-functional PWEs.