• Pranav Nandurkar

Do you know: What is Li-Fi technology?

What is Li-Fi?

Light fidelity - Li-Fi

Li-Fi was first introduced by Harald Haas in 2011. Li-Fi a is wireless communication technology which utilizes light to transmit data and position between devices.It is technically termed as a communication system which is capable of transmitting datad at a high speed.

Physical range  -- visible light, ultraviolet and infrared radiation

Description :

Light Fidelity (LiFi) is a Visible Light Communication (VLC) based technology that making light as a media of communication replacing the cable wire communication. LiFi is evolved to overcome the rate speed in WiFi, while using LiFi the rated speed can reach until 14 Gbps. Li-Fi, which uses visible light to transmit signals wirelessly, is an emerging technology poised to compete with Wi-Fi.It enables the electronic device to connect to the internet with no wire. In order to make a communication line between node, a LiFi will need a transceiver to transmit and receive the data. This transceiver will have a modulation technique to make the LED enable to carry the data using the light. The emergence of LiFi is to overcome the shortage of current technology. Unlike Wi-Fi which uses the radio part of the electromagnetic spectrum, Li-Fi uses the optical spectrum i.e. Visible light part of the electromagnetic spectrum. The principle of Li-Fi is based on sending data by amplitude modulation of the light source in a well-defined and standardized way.

Benefits of Li-Fi :

-As the light source is also available inside the water it can also be used underwater. -One main advantage of Li-Fi is security. Since light cannot pass through opaque structures, Li- Fi Internet is available only to the users within a room and cannot be breached by users in other rooms or buildings. -Its another advantage is, light is available everywhere thus high speed data transmission is available everywhere. -Security proves to be an important advantage of lifi as it cannot be hacked.

Drawbacks of LI-FI :

-One of the main disadvantage is,internet cannot be used without a light source. This could limit the locations and situations in which Li-Fi could be used. -As light cannot penetrate walls, the signal's range is limited by physical barriers. -One of the biggest potential drawbacks is the interception of signals outdoors. Sunlight will interfer withe the signals, resulting in the interrupted Internet.Because it uses visible light, and other sources of light may interfere with the signal. -It requires a near or perfect line-of-sight to transmit data.

Applications :

There are numerous applications of Li-Fi technology, from public Internet access through existing lighting (LED) to auto-piloted cars that communicate through their headlights (LED based). Applications of Li-Fi can extend in areas where the Wi-Fi technology lacks its presence like aircraft and hospitals (operation theatres), power plants and various other areas, where electromagnetic (Radio) interference is of great concern for the safety and security of equipment and people.

Some of the applications are :-


Modulation is used for transmission of data from one point to another. Modulation is the process of transmission of a low-frequency data signal with a high-frequency carrier signal. We need two signals for the modulation process. These are data signal to transmit and high-frequency carrier signal. For three reasons modulation is a necessity. First, the low-frequency data signal has not that much energy to travel far distances. Second, if low-frequency data signal were not imposed on a carrier signal, in other words, if not modulated, the dimension of the antenna would be inefficiently long. It is because the dimension of the antenna is inversely proportional to frequency. Third, data signal bandwidth is 20 Hz-20 kHz and assuming the frequency range of amplitude modulation is 5-10 kHz, there could be a few stations established. For these reasons modulation is in demand nowadays.


Hospitals are a specific case of an environment where both EMI sensitivity and security of data are issues. LiFi can enable the better deployment of secure networked medical instruments, patient records, etc. As Li-Fi does not interfere with radio frequency devices, Li-Fi can be safely used in many hospital applications. For example, in corridors, waiting rooms, patient rooms and operating theatres, Li-Fi technology will allow a light communication network, which will remove electromagnetic interference issues from smartphones and the use of Wi-Fi in hospitals. Li-Fi can also be used for real-time monitoring and report of patient movement and vital signs without the need for wires.