Since its invention by Edison, incandescent light bulbs for the people to have more than a century, but with the advent of LED lights, it's the day left. LED lamp consumes only one-tenth of incandescent, and its service life is 30 times. Moreover, LED lights and is not limited to the use of lighting, as smart bulb invention, it has been given more additional functions, which can make your laptop, smartphone connected to the Internet. Despite Wi-Fi, Li-Fi here.
With the huge growth in the number using WiFi, a large number of WiFi data transmission tremendous pressure for an existing WiFI science and technology by the radio and microwave frequency spectral composition. With the exponential growth of mobile devices, the 2019 is expected to be over 10 billion devices will exchange around 922 trillion Beijing 3372 Zero 368 million 54,775,808 (10 of 18 power) bytes of information. Because the frequency congestion and electromagnetic interference, the current WiFi technology would not be possible transmission of this data. The most prominent problem in urban areas where, because of the city's most WiFi users.
Basic communication principle is the maximum data transmission on the available electromagnetic frequency bandwidth. Radio frequency spectrum is a lot of use and management, but there is not enough additional space to meet the growing needs of users. So Li-Hi is likely to replace radio and microwave frequencies Wi-Fi.
For communication, the visible light spectrum has huge unused and non-regulatory features. Light diode can be modulated very rapidly: with a single blue LED, data rates up to 3.5 Gb / s. White can also be reached with 1.7Gb / s.
Unlike Wi-Fi transmitter, optical communication is carried out in a closed room. This limitation appears to be the limitations of Li-Fi, but its key advantage is very safe: after hanging curtains, outside the room and no one can eavesdrop. Array light source on the ceiling can send different signals to different users. The transmitter power can be localized, it can be more effectively used, and does not affect the adjacent Li-Fi source. Compared to Wi-Fi no radio frequency interference is indeed a great advantage. Visible light communication is very safe, and can make the traveler does not have to put his equipment to switch to flight mode.
Li-Fi A further advantage is that it can use existing power lines, such as LED lighting, it is not necessary to build new infrastructure.
Things burdens help
In a highly interconnected and everything Jieke independent communication with the object world, things are a bold vision. For example, your refrigerator will be drinking milk at the time of, or soon to expire when to send information to inform you on your cell phone. Automotive sensors in tire excessive wear, or notify you by phone when tire pressure is too low.
Because of things in the "goods", you need sensors and controllers for network connectivity, so these devices required communication bandwidth is huge. According to projections, by 2020 there will be 25 billion devices connected to this, in fact, most of these things only need to connect a very short distance, so the Li-Fi will become a realistic solution.
Some companies have begun to offer a visible light communications products. Headquartered in Edinburgh PureLii the Li-1st, to provide wireless point to point security has 11.5Mbps capacity of the Internet - - corresponding to the first generation of Wi-Fi-play solution. Another is Oledcomm from France, the use of Li-Fi connection with the hospital.
Although there are still many technical challenges, but now it has taken the first step to achieve Li-Fi. To be sure, in the future you light switch will turn on something more, not just lighting.
