LED visible light illuminates communication "dead angle"
Calling on the plane, surfing the Internet, using mobile phones in hospital equipment areas or mines, and making smooth conversations in tunnels and subways... For a long time, these places have been blind areas of communication technology or weak signals, and people in them have Communication needs have also to succumb to the current level of technology.
Is it true that these communication "dead spots" will always become blind spots?
the answer is negative. "People's communication needs in these areas can be fully met by LED visible light communication." Xu Zhengyuan, a professor of electronic engineering at Tsinghua University, said that these ideas will be just around the corner, and these scenes will become your normal work and life.
Visible light communication is an emerging wireless optical communication technology based on white LED. It can realize the dual functions of green lighting and communication at the same time. It is one of the most popular research directions in wireless optical communication in recent years.
The LED lamp has high-speed electric modulation performance, and can transmit information through high-speed bright and dark flicker signals that are invisible to the naked eye. This is the fundamental reason why the LED lamp can realize visible light and high-speed communication as a communication light source while displaying the normal illumination. In other words, as long as there is a place for LED illumination, communication can be performed anytime and anywhere.
In addition, LED visible light communication has the advantages of high transmission power, no radio spectrum, no electromagnetic interference, no electromagnetic radiation, private security, energy conservation, etc., which greatly saves communication system cost and improves system capacity.
LED visible light communication research has been in foreign countries for more than ten years, and in some aspects has a higher level of technology. In China, although this research has achieved certain results, there is still a certain gap from the international advanced level and large-scale industrial application.
Professor Xu Zhengyuan returned to China in 2010 in order to promote the research and application of domestic wireless optical communication technology. Prior to this, he spent more than a decade in the United States as a tenured professor at the University of California, and has made great achievements in wireless optical communication, network technology and LED intelligent lighting research. He even led the establishment of the University of California ubiquitous optical communication research center in 2009, and served as the director. He was supported by the US Department of Defense and large enterprises, and his career development is optimistic.
Despite this, Professor Xu Zhengyuan chose to return to China. In 2010, under the support of the National “Thousand Talents Programâ€, Professor Xu settled in Tsinghua. Talking about the reasons, he said that one is to promote the development of domestic LED visible light communication technology, and the second is to reward the cultivation of the alma mater Tsinghua University.
After returning to China, Professor Xu Zhengyuan quickly established a wireless optical information system laboratory at Tsinghua University, using his research experience to promote relevant research on the right track. The laboratory is positioned in a wide range of scientific research covering wide-spectrum wireless light and wireless communications, networking, imaging, sensing, positioning/navigation, intelligent transportation, and the Internet of Things.
At the same time, Professor Xu used his research and network resources accumulated in his overseas experience for more than ten years to lead the laboratory to establish contacts with many well-known international and domestic scholars and related companies in a short period of time, and carried out extensive cooperation and exchanges.
Professor Xu Zhengyuan said that the research and application of visible light communication is not to replace the existing wireless technology, but as an effective supplement to the current situation that cannot be implemented because it is sensitive to RF wireless communication, that is, the article mentioned at the beginning for security. Consider hospitals, engine rooms, mines that shield mobile phone signals, subways, tunnels, and underwater vehicles with strong signal attenuation.
It is understood that the reason why the mobile phone is not allowed during the flight is that the wireless signal sent by the mobile phone will interfere with the pilot's contact with the airport radio and the correctness of the aircraft compass, posing a safety hazard. The use of LED light source does not have such a problem. "You only need to install a central controller on the aircraft, you can use the LED reading light above the seat as a network access point to achieve communication signal connection, not only can call, Can also access the Internet." Professor Xu Zhengyuan revealed that the technology is currently undergoing trial and error of various indicators, and the end of the era of aircraft without communication is just around the corner.
Similarly, LED visible light communication is also suitable for use in mines. The installation of LED lights on miners' helmets, in addition to the inherent lighting functions, can also achieve "communication" between miners. " Moreover, the use of mine tunnel lighting can also access the network, timely transfer of mine data and the ground, so as to achieve the location of the miners and monitoring under the mine, so that the mine is more and more intelligent." Professor Xu Zhengyuan introduced, This research result is now mature in the laboratory and plans to start using it in some mining companies.
In addition, LED visible light communication can also be applied to intelligent transportation systems. “In the body assembly LED lights, between the car and the car, between the car and the traffic lights and street lights can communicate. Drivers can get the most timely traffic, road or location information during driving, choose the best driving route, avoid Collision ensures smooth traffic. In addition, the identity of the vehicle can be realized and managed."
Furthermore, LED visible light communication also has obvious advantages in large-capacity communication in user-intensive areas, and signals between users do not interfere with each other, which is different from the mutual interference of WiFi to limit the overall capacity of the system.
"As a new type of wireless communication means, the advantages of ubiquity and wide coverage provide an infinite space for the development of LED wireless optical communication, which will bring us a more comfortable, convenient and intelligent life." Facing the future, Professor Xu Zhengyuan is full of confidence and believes that the future of wireless optical communication is infinitely bright. What they need to do now is to speed up the research process, to meet the needs of a wide range of information applications for green energy-saving LED lighting and display with mature technology and products, and to write a note for the gorgeous music of wireless optical communication.
Editor's Note:
Xu Zhengyuan is a professor of electronic engineering at Tsinghua University, director of the Wireless Optical Information Systems Laboratory, a doctoral tutor, a national “Thousand Talents Program†special expert and a recipient of the Outstanding Young Scientists Fund. He has long been engaged in research on communication and positioning in the field of wireless light and wireless, especially in the field of ubiquitous wireless optical communication theory, technology, experiment and application system based on green lighting and display LED.
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