Visible Light Communication in 6G: Advances, Challenges, and Prospects

6G networks are expected to provide extremely high capacity and satisfy emerging applications, but current frequency bands may not be sufficient. Moreover, 6G will provide superior coverage by integrating space/air/underwater networks with terrestrial networks, given that traditional wireless communications are not able to provide high-speed data rates for nonterrestrial networks. Visible light communication (VLC) is a high-speed communication technique with an unlicensed frequency range of 400-800 THz and can be adopted as an alternative approach to solving these problems. In this article, we present the prospects and challenges of VLC in 6G in conjunction with its advances in high-speed transmissions. Recent hot research interests, including new materials and devices, advanced modulation, underwater VLC (UVLC), and signal processing based on machine learning, are also discussed. It is envisaged that VLC will become an indispensable part of 6G given its high-speed transmission advantages and will cooperate with other communication methods to benefit our daily lives.