Fudan said that it has achieved "light Internet access" technology

A few days ago, Fudan University stated that an international cutting-edge communication technology that uses the visible light transmission network signal in the house was successfully implemented in the laboratory. The researchers connected the network signal to a 1W LED lamp bead. The four computers under the light could access the Internet. The maximum rate was 3.25G, and the average Internet access rate was 150M. This is the fastest light Internet access in the world.

Visible light communication is called Li-Fi

For a long time, a shiny light bulb was painted on the top of a person and used to symbolize the inspiration of an inventor. However, the German physicist Harald Haas "lit" the illusion by the light bulb itself. A good idea: relying on a tiny lamp, turning the invisible network signal into a "visible" network signal. Haas and his team at the University of Edinburgh in the United Kingdom recently invented a patented technology that uses flashing light to transmit digital information. This process is called visible light communication (VLC) and people often call it affectionately “Li-Fi. "It shows that it can bring revolutionary changes to wireless network transmission technologies currently represented by Wi-Fi.

How far is this kind of unimaginable network technology from us? The answer is: very close, it is coming from the Fudan University laboratory step by step toward us. Xue Xiangyang, a professor at the School of Computer Science and Technology at Fudan University, told reporters that the current radio signal transmission equipment has many limitations. They are rare, expensive, but inefficient, such as mobile phones, and millions of base stations worldwide help them enhance signals, but most of them The energy is consumed in cooling and the efficiency is only 5%. In contrast, the bulbs used in the world are inexhaustible, especially in the domestic LED light source is replacing traditional incandescent lamps on a large scale. Just add a microchip to any humble LED bulb to turn the bulb into a wireless network transmitter.

Visible light communication was safe and economic. Last year, the Shanghai Science and Technology Commission has deployed this internationally advanced wireless communication technology in universities and research institutes throughout the city. Important research and application of key technologies for visible light communication undertaken by Fudan University have made important progress: not only are researchers In the laboratory environment, visible light is used to transmit network signals, and it is possible to achieve "one to four", that is, to turn on a small lamp, and four computers can simultaneously access the Internet and transmit network signals to each other. Prof. Chi Nan of the researcher pointed out that light and radio waves belong to the same type of electromagnetic wave, and the basic principle of transmitting network signals is the same. In the study, a conventional LED light bulb was equipped with a microchip that could control it to flash millions of times per second, with 1 being on and 0 being off. Because the frequency is so fast that the human eye cannot detect it at all, the photosensitive sensor can receive these changes. In this way, binary data is quickly encoded into light signals and transmitted efficiently. Under the light of the computer, through a set of special receiving device, read the "Morse code" in the light.

"If there is a light, there will be a network signal. Turn off the light and there is no network." Chi Nan told reporters that compared with the existing Wi-Fi, the future of visible light communication is safe and economical. Wi-Fi relies on the invisible radio wave transmission, the power of the equipment is getting bigger and bigger, and the local electromagnetic radiation is bound to increase; the wireless signal passes through the wall and the network information is insecure. These security risks have been “sweeping away” in visible light communications. Moreover, the spectrum is 10,000 times larger than the radio spectrum, which means greater bandwidth and higher speed, and the network setup hardly requires any new infrastructure.

Li-Fi technology also has its limitations. Of course, as a new network technology and product still in the laboratory, its future potential should not be overestimated. "Because, from a light communication control to a chip design and manufacturing, a series of key technology products are all researchers' hands-on activities. To truly enter the world like Wi-Fi, it needs to go through a series of industrial development. There is a long way to go.” Chi Nan believes that Li-Fi technology itself also has its limitations, such as if the light is blocked, the network signal will be cut off and so on. Therefore, it is not a competitor of Wi-Fi, but a complement to each other and helps to free up spectrum space. Its future, whether it can produce killer applications, but also rely on people's unlimited imagination: cars rely on LED lights to "talk", passengers in the aircraft cabin to use the head of the LED reading light to the Internet & hellip