LED bulbs work so great that future WiFi will be replaced.

Pacific computer network news. Since the invention of Edison, tungsten filament bulbs have been serving people for more than a century. However, with the advent of LED lights, there are few days left. The power consumption of LED lamp is only 1/10 of that of incandescent lamp, and its lifetime is 30 times that of its incandescent lamp. Not only that, the use of LED lights is not limited to lighting. With the invention of smart bulbs, it has been given more extra functions. It can connect your laptop and smart phone to the Internet. Leaving Wi-Fi, Li-Fi is coming.

In fact, wireless communication with visible light is not a new idea. Everyone knows that smoke signals can be used to attract attention on a desert island. Probably in the Napoleon era, few people knew that Europe had been covered by optical telegraphy, otherwise it would not have called the signal lamp.

With the continuous isolation of a wisp of smoke in the way of Morse code, a rescue message can be formed. Visible light communication -- LI-Fi -- quickly compiles data into binary 0 and 1 by adjusting the intensity of light. For example, LED opens 1, and passes 0. Information can be transmitted through fast switches. But this does not mean that the Li-Fi transceiver will flicker because it is faster than the speed of eye recognition.

Wi-Fi vs Li-Fi

With the huge increase in the number of WiFi users, a large amount of WiFi data transmission has brought enormous pressure to the existing WiFI technology, which is composed of radio and microwave frequency spectrum. With the exponential growth of mobile devices, it is expected that by 2019, more than 10 billion devices will be exchanged, and the information will be exchanged around 922 Beijing 3372 Gigabit 368 billion 54 million 775 thousand and 808 (10 18 times) byte. Because of frequency crowding and electromagnetic interference, the current WiFi technology will not be able to achieve this data transmission. The most prominent problem is the urban area, because the WiFi users in the city are the most.

The basic communication principle is to carry out the maximum data transmission on the available electromagnetic bandwidth. Radio frequency spectrum is widely used and managed, but there is not enough room to meet the growth of user demand. So Li-Hi may replace radio and microwave frequencies Wi-Fi.

For communication, visible spectrum is huge, unused and unsupervised. The light generated by diodes can be modulated very quickly: using a single blue LED with a data rate up to 3.5 Gb/s. White light can also reach 1.7Gb/s.

Unlike Wi-Fi transmitters, optical communications are carried out in closed rooms. This restriction seems to be the limitation of Li-Fi, but its key advantage is that it is very safe: after hanging the curtains, no one can eavesdrop. The array of light sources on the ceiling can send different signals to different users. Transmitter power can be localized, can be used more effectively, and will not affect adjacent Li-Fi sources. Compared with Wi-Fi, no radio frequency interference is really a great advantage. Visible light communication is very safe and allows travelers not to switch their equipment to flight mode.

The further advantage of Li-Fi is that it can use existing power lines, such as LED lighting, so there is no need to build new infrastructure.

Reducing the burden of Internet of things

The Internet of things is a bold idea in a highly interconnected world where everything can communicate autonomously with objects. For example, your fridge will send messages to your cell phone to notify you when the milk is finished or expired soon. The sensor of the car will inform you through mobile phone when the tire is over worn or the tire pressure is too low.

Because the "goods" in the Internet of things require sensors and controllers to connect to the network, the bandwidth required for these devices to communicate is enormous. According to the forecast, by 2020, 25 billion of these devices will be connected. In fact, most of these things only need a short distance connection, so Li-Fi will become a realistic solution.

Some companies have already begun to provide visible light communication products. Li-1st, headquartered in PureLii in Edinburgh, provides a secure wireless peer to peer Internet access with 11.5Mbps capacity - equivalent to the first generation Wi-Fi plug and play solution. The other is Oledcomm from France, using Li-Fi to connect with hospitals.

Although there are still many technical challenges, at present, people have taken the first step to achieve Li-Fi. You can be sure that your switch will open more things in the future, not just lighting.

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