Li-Fi Can be thought of as a light-based Wi-Fi. That is, it uses light instead of Radio Waves to transmit inforatiion
And instead of Wi-Fi modems, Li-Fi would use transceiver-fitted LED lamps that can light a room as well as transmit and recive information.
What is LI-FI?
• Li-Fi is transmission of data through illumination , That is sending data through a LED light bulb that varies in intensity faster than human eye can fallow.
 Harald Haas-who teaches at the university of Edinburgh in the UK, coined the term “Li-Fi” at his TED Global Talk where he introduced the idea of “Wireless data from every light”. He is Chair of Mobile Communications at the university of Edinburgh and co-founder of pureLiFi
 The technology truly began during the 1990’s in some countries.
 But on 12th july2011.He used table lamp with an LED bulb to transmit a video of blooming flowers that was then projected onto a screen behind him.
 Reaching speeds of 224 gigabits per second.
 High-speed communication in a similar manner to WI-FI.
 Visible light communications (VLC) works by switching the current to the LEDs off and on at a very high rate.
Available within the range of base station.Limited availability and also Unavailable in Aircrafts.
Less Security (Pass through the walls).Gama rays cant be used as they could be dangerous.
X-rays have similar health issues.Ultravoilet light ids good for place without people,but other wise dangerous for the human body.

How LI-FI Works?
Operational procedure is very simple, if the LED is on, you transmit a digital 1,if its off you transmit a 0.Thus every light source will works as a hub for data transmission.