Impact of High-Reflectivity Wall Coatings on Non-Line-of-Sight Visible Light Communication Channels

This work investigates the impact of high-reflectivity wall coatings on the performance of NLOS VLC channels. We extend conventional models by incorporating measured Bidirectional Reflectance Distribution Function (BRDF) data to better represent real-world surface behaviors. A comprehensive analysis is conducted through simulations that assess key channel parameters, including received signal strength, delay spread, and achievable data rates. The results demonstrate that specialized coatings significantly enhance NLOS performance, improving signal coverage while moderately affecting multipath dispersion. Unlike prior BRDF-based studies focusing on single-surface cases, this letter provides a systematic, material-aware comparison (ρ = 0.60–0.99) that jointly maps SNR, delay spread, and ISIaware capacity, yielding quantitative design guidelines for NLOS VLC in real rooms.