LiFi Technology

In a recent pilot project, the ministry of electronics and IT successfully tested a technology called LiFi (Light Fidelity), which uses LED bulbs and light spectrum to transmit data at speeds as high as 10 GB per second over a 1-km radius. Indications are strong that it will be soon launched in India on a commercial basis.

The idea is to connect difficult terrains of the country that can’t be reached by fiber but have access to electricity. The technology can be used to connect hospitals where regular internet signals interfere with certain equipment as well as to provide underwater connectivity.

Li-Fi, or light fidelity, invented by German physicist and professor Harald Haas, is a wireless technology that makes use of visible light in place of radio waves to transmit data at terabits per second speeds—more than 100 times the speed of Wi-Fi.

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. Unlike Wi-Fi, which uses radio waves, Li-Fi runs on visible light.

Here, 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 are then converted by the ‘receiver’ into an electrical signal. The signal is then converted back into a binary data stream that the user would recognise as web, video and audio applications that run on internet enables devices.

An LED light bulb is a semiconductor light source meaning that the constant current of electricity supplied to an LED light bulb can be dipped and dimmed, up and down at extremely high speeds, without being visible to the human eye.

Li-Fi could make a huge impact on the internet of things too, with data transferred at much higher levels with even more devices able to connect to one another.

Li-Fi offers great promise to overcome the existing limitations of Wi-Fi by providing for data-heavy communication in short ranges.

Due to its shorter range, Li-Fi is more secure than Wi-Fi.

Since it does not pollute, it can be called a green technology for device-to-device communication in the Internet of Things (IoT).

Li-Fi systems consume less power.

Limitations of Li-Fi:

As visual light can’t pass through opaque objects and needs line of sight for communication, its range will remain very restricted to start with. In order to enjoy full connectivity, more capable LED bulbs will need to be placed at various places.

Li-Fi requires the lightbulb is on at all times to provide connectivity, meaning that the lights will need to be on during the day.

Li-Fi is likely to face interference from external light sources, such as sunlight and bulbs, and obstructions in the path of transmission, and hence may cause interruptions in communication.

Also, initially, there will be high installation costs of visual light communication systems as an add-on to lighting systems.

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