Hyperparameter-Free RFF based Post-Distortion for Multi-RIS Aided DCO-OTFS VLC System with LED Non-Linearity

Abstract

Reconfigurable intelligent surfaces (RISs) have emerged as a promising solution for enhancing visible light communication (VLC) by dynamically shaping the optical propagation environment. Despite these advancements, VLC systems continue to suffer from challenges such as light-emitting diode (LED) non-linearity, user mobility, and multipath, which lead to signal distortion and inter-symbol interference (ISI). To mitigate these impairments, we propose a hyperparameter-free random Fourier features (RFF)-based nonlinear post-distortion for a multi-RIS assisted direct current biased optical orthogonal time frequency space (DCO-OTFS) VLC systems. Furthermore, we have employed the message passing (MP) algorithm for symbol detection in DCO-OTFS VLC systems. The bit error rate (BER) performance of the proposed system is analyzed and validated through computer simulations under multi-RIS VLC channels. Simulation results show that the use of RIS with DCO-OTFS VLC significantly improves BER performance as compared to conventional methods, thus positioning it as a strong candidate for next-generation VLC systems. The proposed approach eliminates manual kernel-width tuning, thereby reducing computational complexity and enhancing robustness across static and mobile VLC channels. © 2025 IEEE.