Li-Fi has often made the news in recent years but has never been commercially materialized. However, things should start to move with the announcement by the French company Lucibel of the marketing of the first Li-Fi luminaire. Developed in partnership with the Scottish company PureLIFI and manufactured in France, the product is in the form of Led ceiling lighting connected to the Internet via an RJ45 (Ethernet) cable and a transceiver that provides modulation and Receives the signal sent by the connected terminal. The latter uses a Li-Fi USB stick to receive the data.
The lifi, for light fidelity is “the internet by light”.
The term Li-Fi was invented by Professor Harald Haas of the University of Edinburgh at a TED conference in 2011
“Internet by Light” is the way Cedric Mayer -one of the co-founders of Oldecomm, a French start-up that sells this application to the general public- calls it.
The big advantage of the Li-fi (Light Fidelity) is to be able to emit 1GBit per second, 10 times faster than Wifi.
How does Li-Fi work?
Li-Fi and Wi-Fi are quite similar as both transmit data electromagnetically. However, Wi-Fi uses radio waves while Li-Fi runs on visible light.
As we now know, Li-Fi is a Visible Light Communications (VLC) system. This means that it accommodates a photo-detector to receive light signals and a signal processing element to convert the data into ‘stream-able’ content.
An LED lightbulb is a semi-conductor light source meaning that the constant current of electricity supplied to an LED lightbulb can be dipped and dimmed, up and down at extremely high speeds, without being visible to the human eye.
For example, data is fed into an LED light bulb (with signal processing technology), it then sends data (embedded in its beam) at rapid speeds to the photo-detector (photodiode).
The tiny changes in the rapid dimming of LED bulbs is then converted by the ‘receiver’ into electrical signal.
The signal is then converted back into a binary data stream that we would recognise as web, video and audio applications that run on internet enables devices. (http://www.techworld.com/big-data/what-is-li-fi-everything-you-need-know-3632764/)
Advantages of LiFi
- LED bulbs are increasingly used (we find them everywhere: car, house, city, etc.)
- This makes it a potential access point
- From an economic point of view, this technology is cheaper than radio technology
- The LiFi has a theoretical transmission potential well above radio wireless (x10,000). At present, the bit rates reached are 10 Gbit / s
- Unlike its WiFi counterpart, the light does not cross the walls. It will therefore be easier to protect access to its network
- LiFi is currently a unidirectional technology. It must therefore be coupled with another technology (CPL, WiFi) or be used in specific cases (need only downflow);
- Obviously to operate the light should always be on and visible from the receiverConclusion : Thanks to advances in throughput and architecture, the LiFi becomes an increasingly credible and promising wireless technology. Despite the fact that it is unidirectional at the moment, the possibilities of use are numerous (road network, geolocation, underwater communication, etc.).
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