The LED bulb has such a big effect on the future WiFi or replaced

The Pacific computer network news, since the invention of Edison, tungsten filament bulbs have been serving people for more than a century, but with the arrival of LED lights, the days are few. The power consumption of the LED lamp is only 1/10 of the incandescent lamp and 30 times its service life. Not only that, the use of LED lights is not limited to lighting, and with the invention of smart bulbs, it has been given more extra functions, it allows your laptop, smart phone to connect to the Internet. Throw away Wi-Fi, Li-Fi comes.

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; in the Napoleon era, few people know that Europe has been covered by optical telegraphy, or it would not have called a signal.

With the continuous isolation of a wisp of smoke in the way of Morse code, a message of rescue can be formed, visible light communication, LI-Fi, quickly compiling the data into binary 0 and 1 by adjusting the intensity of the light. For example, the LED opens 1, and the closing represents 0, which can transmit information through a fast switch. But this does not mean that the Li-Fi transceiver will flicker because its speed of regulation exceeds the recognition speed of the human eye.

Wi-Fi vs Li-Fi

With the huge increase in the number of people using WiFi, a large number of WiFi data transfers have brought great pressure to the existing WiFI technology, which is composed of radio and microwave frequency spectra. With the exponential growth of mobile devices, more than 10 billion devices will be expected in 2019 and will exchange information on the surrounding 922 Beijing 3372 trillion 368 billion 54 million 775 thousand and 808 (10's 18 square) bytes. Because of frequency congestion and electromagnetic interference, the current WiFi technology will not be able to achieve this data transmission. The most prominent part of the 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 extra space to meet the growth of user needs. So Li-Hi is likely to replace radio and microwave frequencies Wi-Fi.

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

Unlike Wi-Fi launchers, optical communication is carried out in a closed room. The limitation seems to be the limitation of Li-Fi, but its key advantage is that it is very safe: no one in the room can eavesdrop after hanging the curtains. The array of light sources on the ceiling can send different signals to different users. The power of the transmitter can be localized and can be used more effectively, and it does not affect the Li-Fi source adjacent to it. Compared to Wi-Fi without radio frequency interference, it is a great advantage. Visible light communication is very safe, and can make the traveler do not have to switch his equipment to the flight mode.

The further advantage of Li-Fi is that it can use existing power lines, such as LED lighting, so that it does not need to build new infrastructure.

The reduction of the Internet of things

The Internet of things is a bold vision in a highly interconnected world where everything can communicate with the object. For example, your refrigerator will notify you on your cell phone when the milk is finished, or the information is sent to your cell phone as soon as it expires. The sensor of the car notifications you through a mobile phone when the tire is overworn, or when the tire pressure is too low.

Because of the "items" in the Internet of things, sensors and controllers are needed for network connections, so the bandwidth required for these devices to communicate is huge. 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 be a realistic solution.

Some companies have begun to provide visible light communication products. Li-1st in Edinburgh based PureLii provides wireless point to point Internet access that is secure with 11.5Mbps capacity - equivalent to the first generation Wi-Fi plug and play solution. The other is Oledcomm from France, which uses Li-Fi to connect with the hospital.

Although there are still a lot of technical challenges, people are now taking the first step in achieving Li-Fi. It is certain that in the future, the switch of your lamp will turn on more than just lighting.

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