2. INTRODUCTION
Lifi (Light Fidelity) is transmission of data through
illumination i.e., Sending data through a light emitting
diode (LED) that varies in intensity faster than human
eye can follow
3. HISTORY
Harald Hass began his
research on Li-Fi in 2004.
On 12th July 2011, he gave
his debut demonstration at
TED Global conference by
streaming a video through an
LED bulb.
4. WORKING
A modulator turns the
LED ON and OFF in
rapid successions
A controller codes the
data into LED’s
The flickering of light
transmits that data as
digital 0’s and 1’s
ON means a digital 1
and OFF means a
digital 0
5. WORKING (CONT’D)
The light transmitted is detected by photosensitive
devices
That light is amplified
Decoder decodes the light waves and converts data
into 0’s and 1’s
That data is then fed to the system
6.
7. DIFFERENCE BETWEEN WI-FI AND LI-FI
Data transfer speed--
150Mbps
Medium used is Radio
Waves
Range less than that of
visible light spectrum
Expensive as compared
to light spectrum
Data transfer speed--
>1Gbps
Medium used is Light
Waves
Spectrum range 10000
times more than radio
waves
Much cheaper than
Radio spectrum
Wi-Fi Li-Fi
8. APPLICATIONS
In traffic lights and cars so that they can
communicate with each other
In RF restricted areas such as petrochemical plants
In airplanes
In street lamps as free access points
In ocean beds
9. LIMITATIONS
Light can not pass through objects
Interference from external light sources will cause
interference
High installation cost of the Visible Light
Communication (VLC) systems
10. IN THE NUT SHELL…
Li-Fi will make our lives more technology driven if
more researches will be carried out in the field to
overcome the limitations
Every bulb can be used as a Li-Fi spot to transmit
data
