Light fidelity (in short Li-Fi) is a light-based wireless communication technology. The term Li-Fi was first introduced by Harald Hass, German Professor of Mobile Communications at the University of Edinburgh. Unlike Wi-Fi which uses radio waves for transmitting the data, Li-Fi uses lights (such as LEDs) to transmit the data. It is a high speed, bidirectional, networked wireless communication. Its physical range includes visible light spectrum, UV and infrared radiation.


LED can be turned ON and OFF quickly and the intensity can be rapidly modulated such that it is not visible to the human eye even though it is flickering. When powered ON, LED transmits ‘logic 1’ and powered OFF, LED transmits ‘logic 0’.


LED driver regulates the input power supply to LEDs. LEDs are switched ON and OFF to generate digital strings of combinations of binary 1’s and 0’s. This process can be enhanced by using multiple LEDs or by using LEDs of different colors for more complex data transmissions. Photodiode receives the optical signal and convert it into an electrical signal. The processed output is then fed to the required device.


1) High speed.

2)Highly secured as light cannot pass through opaque surfaces. Therefore, it is safe from hackers.

3)Energy efficient.

4) Very high operating frequency.

5) Since Li-Fi uses light for transmitting data, it will be less harmful for the living organisms.

6) It does not cause electromagnetic interference.


1)Interference from sunlight

2) Shorter range

3) Requires light source


1) Street lights can be used as Li-Fi hotspots.

2) It can be used in underwater applications.

3) It can be used for vehicle to vehicle communication. Therefore, it helps in preventing accidents.

4) Li-Fi will not result in electromagnetic interference. Therefore, it is


It is a developing visible light communication technology. At present, it is not widely used. As internet has become an integral part of our day to day life, Li-Fi which is more beneficial than Wi-Fi will be able to cause a remarkable revolution.