Considerations on modulations and protocols suitable for visible light communications (VLC) channels: Low and medium baud rate indoor visible ligth communications links

Abstract

This paper describes some applications under development for optical wireless systems based on visible light communications (VLC). The indoor scenario defines services which can be provided to users inside a room such as video broadcasting or home automation. For this purpose a 2Mbps visible downlink and a 125 kbps infrared uplink were used. In this work, we present the Ethernet interface that has been implemented in each AP (access point), the light modulation used and the sensor network developed for demonstration. The main advantages of VLC technology are the robustness against electromagnetic (EM) interference, safety for human eye, and security against undesired network access.