Wavefront shaping for multi-user line-of-sight and non-line-of-sight visible light communication

Abstract

Visible light communication (VLC) has become a popular method for indoor communication, due to its high transmission speed and robustness against electromagnetic interference. Indoor VLC scenarios commonly consist of multiple users in line-of-sight (LOS) and non-line-of-sight (NLOS) paths. In NLOS, the light waves suffer from attenuation due to diffuse reflection from obstacles in the room, leading to significant attenuation in light intensity. This paper proposes a wavefront shaping method to enhance indoor VLC for multiple users, including both LOS and NLOS. By employing a spatial division scheme, we can simultaneously achieve a light intensity gain of 5.43 dB in NLOS through stepwise partitioning wavefront shaping and an opening angle range of 27° for two LOS users through computational holography. By employing bit-power-loading discrete multi-tone (DMT) modulation, we demonstrated VLC with transmission data rates of 3.082 Gbit/s and 3.052 Gbit/s for two LOS links and 2.235 Gbit/s for NLOS with 30.7% improvement compared with that without wavefront shaping, satisfying the 7% forward-error-correction (FEC) threshold.