Li-Fi is a wireless optical technology that uses the same 802.11 protocols as Wi-Fi. Since Li-Fi uses visible light communication (VLC), it has a much higher bandwidth than Wi-Fi. Li-Fi technology requires a light source fitted with a signal processing chip/unit, typically an LED bulb such as those currently used in homes and offices, and at least one photodiode device that can receive light signals. If the LED is on, a digital 1 is transmitted, if the LED is off, a digital 0 is transmitted. These LEDs can be switched on and off rapidly, unnoticed by the human eye, thus transmitting data.
Although Li-Fi is not currently in common use, it is beginning to be tested in some office buildings. It is believed that it has the potential to reach speeds of up to 10 GB per second, which would mean that a full-length HD movie could be downloaded in just half a minute.