Run out of internet through light

　　Since its birth in France in 2009, visible light wireless communication technology has developed rapidly, successfully passed tests in office buildings, museums and supermarkets, and is expected to enter thousands of households in the near future.
　　At home, French quantum physics professor and researcher Souart Taupsou can download movies, attend teleconferences at work or surf the Internet simply by turning on the lights without connecting to a Wi-Fi network! To be precise, what he turned on was a new type of light—light-emitting diodes. This kind of technology that can connect to the Internet as long as people are under the light is called visible light wireless communication technology, which came out at Paris-Saclay University 13 years ago. Its principle is simple: install a light-emitting diode on the ceiling, connect it to an Internet box through wires, and transmit the data from the Internet box through the light beam of the light-emitting diode. “We can compare visible light wireless communication technology to Morse code: digital information is converted into flashes of light, just like we are constantly switching lights on and off, but the frequency is millions of times per second. This frequency is the human eye. imperceptible. These signals are then translated into computer language by a receiver like a large USB stick (plugged into a computer, tablet or mobile phone), ” says Frédéric Granotier. He is an expert in the lighting field of visible light wireless communication technology in France and the president of Light Flash Technology Company.
　　”We already have more than 100 customers, including banks and some corporate headquarters. In addition, we have just won a tender for a university in Toulon, Var, to install our products for three teaching buildings.” , Granotier was excited.
　　Does this mean that we can relegate wireless networks to the ranks of obsolete technologies, like mininets (the national network France created itself in 1982, predating the Internet) and wired telephony?
　　In places where radio waves cannot pass or the signal is poor, such as subways, underground parking lots, trains or airplanes, visible light wireless communication is indeed a good substitute. On October 30, 2019, on an Air France plane flying from Paris to Toulouse, passengers actually participated in an e-sports competition during the flight through the wireless network generated by the LEDs installed in the seats.
　　| Safe and harmless, a hundred times faster than wireless networks|
　　The hazards of radio waves are still debated, while the carrier of visible light wireless communication – light – is generally considered harmless. Since 2015, the Abeye Law has banned the use of Wi-Fi in establishments hosting children under the age of three. The law, proposed by French MP Lawrence Abeye, aims to reduce the harm caused by electromagnetic waves to children. Nurseries and kindergartens are therefore likely to be interested in VLC technology. In Courbevoie, Haute-Seine, an early childhood education institution decisively installed visible light wireless communication equipment in 2016.
　　The emergence of visible light wireless communication technology can also solve the saturation problem of radio waves, Taupsu said. “In the next few years, there may be 80 billion connected products in our homes. There will be no interference between them, and the popularity of fifth-generation mobile communication technology means that we need to increase the number of base stations. In order to avoid excessive exposure to radio In waves, we can use this technology instead,” he said.

　　This invention is also especially necessary for places where sensitive information is often transmitted, such as hospitals, nuclear power plants, research and development centers, etc. “If you want to receive a signal, you have to be under the beam. Since light cannot penetrate walls, this makes visible light wireless communication technology very safe. Wireless networks are different. People can search from nearby rooms or on the street. The military also There is a lot of interest in this technology because visible light wireless communication devices are easier to install than wired connections on the battlefield,” Granotier said. Most importantly, visible light wireless communication is 100 to 150 times faster than wireless network communication! In June 2020, a Grenoble researcher broke a world record by transmitting data at a rate of 7.7 gigabits per second. What is the concept of 7.7 gigabits per second? Just fast, very fast! “It’s so fast that we can download more than 20 movies in one second,” Taupsu said.
　　Harmless, safe, fast… Visible light wireless communication technology seems to be impeccable, except for one thing: what happens if you turn off the light? “It will break the network. Unless we use infrared light, which is invisible, but in this way, the speed will be slowed down.” Taupsu added. Visible light wireless communication technology is especially suitable for indoor connections. If we look at our mobile phone while walking on the street, or turn on the navigation in the car, we can only use the existing network. “Visible light wireless communication technology cannot replace the fourth-generation and fifth-generation mobile communication technologies or wireless networks, but can only be used as a supplementary solution. We can switch from one technology to another according to needs. In office buildings, every 1.5 There is one light source per square meter, and in this case, visible light wireless communication technology is more suitable.” Taopusu said.
　　| Multipurpose |
　　Slowly, visible light wireless communication technology has entered the public eye. Today, several museums have installed this wireless communication system, including the Curtius Museum in Liege, Belgium, and the Playing Card Museum in Haute-Seine, France. Visitors can receive a tablet at the entrance, and whenever they walk near a work, they can receive relevant information under the lights to enrich their visit. The Saint-Grégoire-Leclerc supermarket near Rennes is also testing the communication technology in its cultural section: customers can check book reviews on tablets or watch movie clips on the CD-ROM shelf in front of them. A Leclerc supermarket in Paris is using the technology to connect shopping carts to the Internet and analyze the journey of customers in the store.

　　At present, the high price of visible light wireless communication technology is the main reason that prevents it from entering thousands of households: a lamp from Lightblink Technology is worth 1,000 euros. In addition, the receiver will also be updated, and the plug-in is destined to be replaced by the embedded. “Peripheral devices will eventually disappear. With the development of fifth-generation mobile communication technology, manufacturers will redesign their computers, tablets and smartphones, which also provides an opportunity for the popularity of visible light wireless communication technology. Homes should be in 2025. Use this technology back and forth,” Taupsu concluded in a teleconference. Then, he turned off the light.