Name: visible light wireless communication (called LiFi-optical fidelity)
Generate background:
WiFi technology has become more and more popular, but more and more people complain that the wireless signal is unstable, the internet speed is slow, and there are too few WiFi hotspots. Now, there is a new technology that can solve these problems.
The light bulb has always been regarded as a symbol of the inspiration of the inventor's dream. But for German physicist Herald Haas, the light bulb itself inspired him. Haas of the University of Edinburgh and his team have invented a patented technology, which uses flash to transmit digital information wirelessly. This technology is often called visible light communication (VLC).
Technical principle:
Visible light wireless communication (called LIFI-optical fidelity) uses fast optical pulses to transmit information wirelessly. It is completely feasible to encode optical information at different rates. For example, when the LED is on, it means 1, and when it is off, it means 0, so information can be transmitted by fast switching. Because of the luminous intensity of LED, human eyes will not notice the rapid change of light. LiFi technology is still in the laboratory stage, which is a patented technology invented by Haas of Edinburgh University and his team. The light bulb has always been regarded as a symbol of the inspiration of the inventor's dream. Like optical fiber communication, it has the advantages of high bandwidth and high speed. The difference is that LiFi allows light to spread in our surroundings. Where natural light energy reaches, there will be LiFi signal. Li Fei technology is to use the laid equipment (ubiquitous light bulb), as long as tiny chips are implanted in the light bulb, it can become an AP(WiFi hotspot)-like device, allowing the terminal to access the network at any time.
Main uses:
Li-Fi encodes by adjusting the data of LED light output. The human eye can't detect the rapid flicker, but the receiver or mobile device on the desktop computer can read the signal and even send it back to the signal transceiver on the ceiling of the room to provide two-way communication. However, many light emitting diodes use phosphor coatings to convert blue light into white light, which also limits the data transmission rate. The study was published in Optical Express, and Haas and his team showed that replacing the existing LED lamps with laser diodes can greatly improve the current situation. Laser has high energy and light efficiency, and the data transmission rate can be 10 times faster than LED. Without phosphors, laser illumination can mix different wavelengths of light to produce white light. This means that each wavelength of light can be used as a separate data channel, and the same light wave can be transmitted in both directions, which can greatly improve the data transmission rate of light. The experiment of the University of Edinburgh team used nine laser diodes.
Although the data transmission rate of LED-based Li-Fi can reach 10 Gb/s, the upper limit of data transmission rate of Wi-Fi can be increased by 7 GB/s. The data transmission rate of laser can easily exceed100 GB/s.
At present, this kind of equipment is still very expensive, and the University of Edinburgh is seeking mass production to reduce its cost and apply it to the lighting market. The headlights of BMW i8 are based on this laser light.
References:
The successful networking speed of 1 Lifei technology is 100 times faster than WiFi. Netease
2.LiFi: visible light wireless communication. LIFI: visible light wireless communication
3. change WiFi? LiFi using visible light communication still has a long way to go. Tencent
4. The laser Li-Fi transmission speed of Edinburgh University can exceed 100G per second. Phoenix technology