Hybrid PD/SPAD receiver for vehicular dynamic VLC

To address the issue of link stability in vehicle-to-everything visible light communication (VLC) systems being susceptible to dynamic environmental factors in complex road conditions, which directly reduce the effective communication range, this paper proposes a hybrid receiver architecture based on a linear photodiode (PD) and a single-photon avalanche diode (SPAD) array. The architecture builds a dynamic optical scheduling core, i.e., the hybrid controller, by means of a micro-electro-optical selective switch, which achieves adaptive switching of the incident signal between the linear receiving path of the PIN module and the photon detection path of the SPAD array module. Our hybrid PD/SPAD receiver advances beyond prior indoor-focused designs by addressing outdoor vehicular challenges: weather attenuation, turbulence, pointing errors, and dynamic illumination. The resulting adaptive path selection ensures stability and minimizes BER across all operating conditions. Simulations at a target BER=10^-3 show that under low-light fog (visibility V=0.5km), the hybrid extends reliable range from 60 (PIN-only) to 157 m (+162%); under sunny conditions with 20 mW background illumination, it achieves 29 versus 16 m for SPAD-only (+81%); and under cloudy conditions (V=5km) it maintains >50Mb/s at 200 m while reducing outage probability by 85% relative to the best single-path baseline. By automatically selecting the optimal detection path as channel conditions vary, the proposed architecture enhances link reliability, extends operating range, and improves availability for robust V2V-VLC in complex road environments.