What is visible light communication (LiFi)

LiFi is an emerging wireless communication technology based on light, not radio, that combines the lighting and data communication capabilities of light, as shown in Figure 1. While LiFi is not affected by LED lighting, the signal is modulated on the LED light source, and the high frequency scintillation signals that can't be perceived by the eye can be generated by fast switching to transmit data.

Compared with the current mainstream WiFi communication technology, LiFi has the following advantages:

(1)In terms of capacity, the spectrum of radio waves is very crowded, and the spectrum width of visible light (about 400 THz) is 10,000 times larger than that of radio waves.

(2)efficiency, the efficiency of the radio wave base station is only 5%, most of the energy is only consumed in the cooling of the base station, and the LiFi data can be transmitted in parallel, while improving the efficiency。

(3)in practical terms, radio waves are only obtained in the base station, and WiFi can not be used on aircraft, operation room or gas stations, and every light in the world can easily access LiFi hot spots.

(4)In terms of security, radio waves are easy to be intruded, and visible light can not penetrate walls, or even curtains, providing network privacy security.

As a new technology for lighting and communication, LiFi can not affect the quality and requirements of lighting while pursuing high transmission rate, especially in the development of light source. The light source of LiFi should not only have the advantages of good modulation performance, high transmitting power and high sensitivity of response, but also meet the characteristics of high brightness, low power consumption and wide range of radiation.