In recent years, with the development of white light-emitting diode (LED) technology, visible light communication (Visible Light CommunicaTIon, VLC) has become one of the research hotspots of next-generation wireless communication technology. VLC is also called LiFi (Light Fidelity). In 2011, Professor Hardal Hass, a German physicist from the University of Edinburgh, gave a speech on LiFi technology at the TED conference. For the first time, "VLC" was called "LiFi."
LiFi is an emerging wireless communication technology based on light (rather than radio waves) that combines the lighting and data communication functions of light, as shown in Figure 1. LiFi modulates the signal on the LED light source without affecting the LED illumination, and transmits data by fast switching to generate high-frequency flicker signals that the human eye cannot perceive.
Figure 1 LiFi is a light-based wireless communication technology
Advantages of LiFi
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 more than that of radio waves;
(2) In terms of efficiency, the efficiency of the radio wave base station is only 5%, most of the energy is only consumed by the cooling of the base station, and the data of the LiFi can be transmitted in parallel while improving the efficiency;
(3) In terms of practicality, radio waves are only acquired in the base station, and WiFi cannot be used on the aircraft, in the operating room or at the gas station, and each lamp in the world can be easily connected to the LiFi hotspot;
(4) In terms of safety, radio waves are easily invaded, and visible light cannot pass through walls or even curtains, providing privacy and Security for the network.
As a new technology that combines lighting and communication, LiFi does not affect the quality and requirements of lighting, especially in the development of light sources, while pursuing high transmission rates. The light source of LiFi must have the advantages of good modulation performance, high transmission power and high response sensitivity of the communication light source, and it also needs to meet the characteristics of high brightness, low power consumption and wide radiation range of the illumination source.
On April 8th, there was a wireless communication technology seminar to guide the development of the offline, so that the development of technical problems is worry-free ~!
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