The document discusses light-based Wi-Fi (Li-Fi) which uses visible light communication and LED lamps to transmit data wirelessly. It notes that Li-Fi has significantly higher capacity than radio-based Wi-Fi as the light spectrum is much larger. It also describes how Li-Fi has advantages over Wi-Fi such as better security since light cannot pass through walls to intercept signals. The document outlines some of the key components used in a Li-Fi system like LED lamps that can transmit data by varying in intensity and a photodetector that receives the signals.