Light–Fidelity (Li-Fi) technology came into existence in 2011. The term was first used by Harald Haas in his TED Global talk on Visible Light Communication. It allows wireless communication without the use of radio waves, which can be dangerous in places like oil platforms, underwater and on planes. Li-Fi can be thought of as a light-based Wi-Fi.
Heart of Li-Fi technology is high brightness LED’s. The LED bulb will hold a micro-chip that will do the job of processing the data. The on-off activity of LED’s enables a kind of data transmission using binary codes. Switching on an LED is a logical “1”; switching it off is a logical “0”. A light sensitive device (photo detector) receives the signal and converts it back into original data.
VISIBLE LIGHT COMMUNICATION: Li-Fi is a faster and cheaper version of Wi-Fi, which is based on Visible Light Communication. The visible light communication is a data communication technique using visible light between 400 THz and 800 THz as an optical carrier for data transmission.
Devices used in Visible Light communication: Devices which are used for transmission purpose in VLC are visible light LED and fluorescent lamp. This technology uses fluorescent lamps to transmit signals at 10bit/s, or LED’s for upto 500 Mbit/s. Devices which are used for reception purpose in visible light communication are photo diodes and image sensor
Comparison of Li-Fi with present transmitting technologies:
Wi-Fi : 150 Mbps, Bluetooth: 3 Mbps, IrDA: 4 Mbps, Li-FI: > 1 Gbps.