An Introduction to the Li-Fi Technology

      The term Li-Fi or Light Fidelity was coined first in 2011 by Professor Harald Haas from University of Edinburgh during a TED talk in 2011. He proposed a theory by which light bulbs could act as wireless routers. A Li-Fi is a Visible Light Communications(VLC) system running wireless communications travelling at very high speeds. Li-fi uses common household LED lights to transfer data and it provide a speed upto 224 Gigabits per seconds.

      Wi-Fi and Li-Fi is quite similar to each other. They both works on the same principle i.e. Transmitting data or connection in the form of electromagnetic radiations with the only difference that Wi-Fi uses radio waves to transmit data, whereas, Li-Fi uses light waves for propagating data.

How it Works???

      Its working is quite simple, but you have to first understand how does a LED Light works. When a constant current is passed through an LED, It starts emitting radiation in the form of small packets of energy called photons, which we perceive as Visible range of light. If the input current varied slightly, the output intensity of light i.e. photons also varies. Human eye is perceptible hardly for 60 FPS(Frame per seconds). Frequency higher than this limit is can't even noticed by human eye. Since, LED is a semiconductor device, current can be modulated at very high frequency so as the output. These very fast variations in intensity is detected by photodetector device and converted back to the electric current form which can be interpreted as bits.

Upside of using LiFi

      Lights are almost everywhere you go, from your room to Malls, Cafes etc. It's impossible to make a complete list of existing places for light. LiFi relies on the visible light technology. This means where there is a light, Internet connectivity also there. Also visible light has a far broad spectrum than radio waves ever have(approx 10,000 times broader spectrum). LiFi is also said to increased Bandwidth by 100 times what we have today with WiFi.

      LiFi is more secure than WiFi  due to its shorter range. It is also have seen that waves bouncing back after striking a reflecting surface can still achieve a speed of 70 Megabits per second, which is still higher than the current WiFi technology.

Downside of using LiFi

     Along with above benefits, there is also some disadvantages using LiFi. LiFi is useless where there is no LED lights or OFF state light bulbs. This means that you can't access internet while at bed during night. Also, Light waves can't pass through the walls, so you must be present within the perimeter in order to access the internet, and you have to keep your lights on even during the day. Apart from these, WiFi uses radio waves, which can be passed through the walls, though looses some strength, but still you can access internet. This technology is also not very reliable as well as less pocket friendly due to its high installation charges.