Visible light communications: the road to standardization and commercialization (Part 2) [Guest Editorial]

Visible light communications (VLC) has a long history dating back to ancient signal fires, followed by the 1880 Alexander Graham Bell photophone, which transmitted speech wirelessly using modulated reflected sunlight. But it was the emergence of solid state light sources that sparked the imagination of researchers, such as those at Nakagawa Laboratories at Keio University around the turn of the 21st century, to demonstrate that solid state light sources could be used for secondary purposes such as data transmission and positioning.