What is Light Fidelity or Li-Fi
- Li-FI (light fidelity) is a wireless system that transmits the data using LED or Infrared light. In simple term it is a light based Wi-Fi technology. As we know, this Wi-Fi is fully networked, bi-directional wireless communication technology and here the data is being transmitted using the radio waves.
- While in case of the of Li-Fi technology, the data is transmitted in the form of visible using the light LED light source. So the house hold LED bulbs and LED lamps which are used as a light source can also be used to transmit the data.
How Li-Fi technology work
- As we can see any LED light source, if we provide LED light source with constant current then it will provide us with constant illumination or constant brightness. So as we change the current that is flowing through the LED bulb, the illumination or brightness of the bulb will also change. So this principle is used for transmitting the data wirelessly using this technology.
- So when no current or minimum current is flowing through this led bulb then, the brightness of the LED source will be minimum which is treated as a digital zero (0). This digital 0 will be transmitted at the reciever side. Similarly, when the light bulb is ON, or we can say that if the maximum amount of the current is flowing through the LED bulb then the illumination or brightness of the LED bulb will be maximum and that will treated as digital one (1) So whenever the LED is ON, digital! Will be transmitted at the receiver end.
- So in this way by flickering the LED light source very rapidly we can transmit the data in the form of 1’s and 0’s to the receiver. And if this flickering is happening at the million times per second then we can not see this flickering by our naked eyes. Because of this we can treat the LED bulb source as a normal regular bulb source.
The schematic of Li-Fi transmitter and receiver system
- As we can see the data which is coming from the web server or the internet first it will reviece at Modem, which provide the necessarily modulation to the incoming data stream. Once this modulation is done as it requires then this modulation data is fed to the LED driver, which changes the driving current for this LED bulb according to the incoming streaming data.
- At the receiver end, if we see their optically received data is firstly converted into the electrical signal using the photo receiver or photo diode. And once the signal conditioning this data is being fd to the computer or laptop. So for this we require incoming data receiver i.e. Li-Fi dongle which consist of photo receiver as well as IR transmitter.
- The company named Pure Li-Fi is one which provides the complete Li-Fi solution. They generally manufacture these Li-Fi dongle
Let us see the advantages of the Li-Fi technology over the other wireless technology that is Speed, Security, Safety, Congesting free
a) Up till now the researchers have achieved the speed up to 10 Gbps in the Lab scale prototype models and also this speed can be upgraded further by using the array of LED source or by using multiple color of LEDs like RGB LEDs, where each LED can transmit the data up to 10 Gbps.
b) So now when compare this technology to 4G/LTE or particularly the LET advanced, the maximum achievable speed under LTE advance is 1 Gbps for the stationary user and 100 Mbps for the mobile user. But all this speed is theoretically achievable speed but actually speed is much lesser.
c) The countries which provide fastest speed in the world has a rate of 40-50 Mbps. which is much lesser compare to the Li-Fi. While we compare with latest Standard under IEEE in case of Wi-Fi the maximum speed reaches to 1.3 Gbps that is under the 5 GHz band which is almost 100 times lesser compared to the Li-Fi speed. Therefore the Li-Fi technology allows 10 times fastest speed then that of Wi-Fi technology.
