• LIFI Light Fidelity
• It can be thought of Wi-Fi “but”
transferring data using light
instead of radio waves as used by
• Fast and cheap version of Wi-Fi
as wherever there is light, there is
We can transfer data using light speed.
Thus, a high definition film can be
downloaded in 15-20 seconds.
It works on LED’s ON/OFF concept
encoded binary ‘one’ for light ON and
binary ‘zero’ for light OFF condition.
The Ted Talk show has 2,389,880+
Direct line of sight is not necessary for
Li-Fi to transmit a signal; light reflected off
the walls can achieve 70 Mbit/s
•Some waves like UV, IR, gamma ,x rays are harmful for the human
body and can cause serious problems.
•Radio waves are less secure and expensive too.
•Thus, use of light spectrum came to the idea in transferring data.
which has a higher bandwidth.
•Radio waves are limited.
• It is 1000x times more spectrum than radio waves.
•When a constant current is applied to an LED light bulb a constant
stream of photons are emitted from the bulb which is observed as
•If the current is varied slowly the output intensity of the light dims up
and down and this forms principle of the technology.
•Because LED bulbs are semi-conductor devices, the current, and
hence the optical output, can be modulated at extremely high speeds
which can be detected by a photo-detector device and converted back
to electrical current.
•The intensity modulation is imperceptible to the human eye, and thus
communication is just as seamless. Using this technique, high speed
information can be transmitted from an LED light bulb.
Li-Fi is a fast and cheap optical version of Wi-Fi. It is
based on Visible Light Communication (VLC).VLC is a data
communication medium, which uses visible light between 400
THz (780 nm) and 800 THz (375 nm) as optical carrier for
data transmission and illumination. It uses fast pulses of light
to transmit information wirelessly. The main components of
Li-Fi system are as follows:
•a high brightness white LED which acts as
•a silicon photodiode with good response to visible
light as the receiving element.
“Pure LiFi seeks to resolve the global struggle for diminishing wireless capacity by
developing and delivering technology
for secure, reliable, high speed communication networks that seamlessly integrate
data and lighting utility infrastructures and significantly
reduce energy consumption.”
A striking advantage of LiFi over Wifi is that it can boost
the network speeds about 100 times faster that the
conventional Wifi system available. Tested under real life
conditions. the achieved speeds were up to 1 Gbps.
Light cannot penetrate through walls to reach
outside your workstation. And so, rest assured, it
won’t be able to reach your neighbor in any ways.
Wherever there is a light source, there can be
Internet. Light bulbs are present everywhere – in
homes, offices, shops, malls and even planes,
meaning that high-speed data transmission could be
Traffic Updates :Could you imagine having a car that uses a
GPS system that receives information from traffic lights
informing you of accidents and/or delays up ahead? There is a
kind of system like that already in play for GPS navigational
systems, but the traffic lights could be updating drivers using
basic information or streaming video directly from news
Underwater communication : Radio waves are quickly
absorbed in water, preventing underwater radio
communications, but light can penetrate for large distances.
Therefore, Li-Fi can enable communication from diver to
diver, diver to mini-sub, diver to drilling rig, etc.
It can be used in airplane and hospitals where wifi facility
usually not there . It can also be used in wireless gaming
providing new environment to sensors and all other stuff.
•One of the major drawback of this system is that light should be
turned on whenever you need to access internet.
•It range is lower than normal wifi system.
• The possibilities are numerous and can be explored further.
• If his technology can be put into practical use, every bulb
can be used something like a Wi-Fi hotspot to transmit
wireless data and we will proceed toward the cleaner,
greener, safer and brighter future.