Experimental study of SPAD-based long distance outdoor VLC systems

The single photon avalanche diode (SPAD) is used for the long-distance visible light communication (VLC) system owing to the high sensitivity and high detection efficiency. In this paper, a SPAD-based real-time outdoor VLC system for long distance applications is presented based on non-return-to-zero on-off keying (NRZ-OOK) modulation. Then we propose the practical maximum likelihood detection (PMLD) and real-time pulse correlation synchronization (RPCS) schemes for the SPAD-based system. Finally, the influences of different practical conditions are discussed. Experimental results show that the maximum data rate achieved by the system is 2 Mbps with the bit error rate below 10−6 when the communication distance is 1.2 Km.