2. Table of Contents
• What is Li-fi?
• Introduction
• History
• Present Scenario
• Issues of Using Radio Spectrum
• Who can resolve this issue?
• Principle of Li-Fi
• Why Li-Fi use VLC?
• Li-Fi Vs Wi-Fi
• Applications Of Li-Fi.
• Merits And Demerits
• Conclusion
3. What is Lifi?(LIGHT FIDELITY)?
Light based Wi-Fi
Light is used instead of radio
waves to transmit information.
Transceiver fitted LED lamps
acts like Wi-Fi modems.
LED lamps can light a room as
well as transmit-receive
information.
Sending data through a LED
light bulb that varies in intensity
faster than human eye can
follow.
4. HISTORY
Professor Harald Haas Prof. Harald Haas, from
university of Edinburgh in the UK
is the founder of Lifi.
On 20th July 2011 he used a table
lamp with an LED bulb to
transmit a video of blooming
flowers that was then projected
onto a screen behind him. During
the event he periodically blocked
the light from lamp to prove that
the lamp was indeed the source
of incoming data.
6. Present Scenario
Radio Spectrum is congested but the demand
for wireless data double each other.
Data in the form of tera bytes travel every
week or month.
Every one want to use wireless data but the
capacity is drying up resulting in different
issues.
So, what can carry this excess demand in
future
7. Issues Of Using Radio Spectrum
Spectrum is 10,000
times greater than
that of radio
frequency.
Light waves available
everywhere.
Highly efficient
since LED consumes
less energy.
Cannot penetrate
through walls. Hence
data can be secured.
11. Why Li-fi use Visible Light
Communication?
Gama rays, X-rays , Ultraviolet rays are harmful for
the human body.
Infrared Rays are also dangerous due to eye safety
regulation and can only be used with low power.
Radio waves are expensive and they are less secure.
Therefore, only Visible rays or visible light spectrum
is left which is not harmful for humans.
Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays X-Rays
Gamma
Rays
12. Characteristics Wireless Fidelity Light Fidelity
Range 100 meters Based on LED
Power Consumption Medium Low
Cost Expensive in comparison
with LiFi because it uses
Radio Spectrum
Cheaper than Wifi because
free band doesn’t need
license and uses light
Security Moderate Secured Highly Secured
Data transfer rate Within MBPS Greater than GBPS
Medium Through which
data transfer
Use radio Spectrum Use light as a carrier
Spectrum Range Radio Spectrum Range is
less than visible light
spectrum
Visible light spectrum is
10,000 times broader than
Radio spectrum range
13. Applications of Li-Fi
Traffic Scenario:-
• Lifi can be used to communicate
with the LED’s of cars.
• This might prevent accidents by
exchanging information when the
vehicles are too close.
• Using Lifi, street lights can be
used to send information about
the road condition of the car.
14. Home And Small Offices
In home and small offices,
Li-fi can be used to
communicate with the
devices such as:
Laptops
Internet access
HD Video Streaming
Printer
15. Street Lamps & Ocean Beds
An Ocean Beds
Li-Fi can even work under
water where wifi fails.
Communication between
Naval becomes easy.
Street Lamps
There are millions of Lamps
deployed around the world.
Each of these street lamps
could be a free access point.
16. Merits & Demerits
Merits
Data rate greater than 10Gbps
theoretically allowing HD film to
be downloaded in 30 seconds.
Can be used everywhere even in
RF areas, since light waves will
not interfere with radio waves.
As light waves cannot penetrate
through walls, hence data cannot
be intercepted which results in
providing secured communication
Mostly LED light bulbs are used
which consumes less energy.
Hence cost efficient.
Demerits
A major challenge of Li-Fi is how
the receiving device will transmit
back to receiver.
Data transmission can be easily
blocked by any object placed in
front of LED source.
Interferences from external light
source like sunlight, in the path of
transmission can cause
interruption in the communication.
17. Conclusion
Researchers are developing a micron size LED’s.
1000 micron sized LED can fit into an area required
by 1sq.mm large single LED.
A 1sq.mm sized array of micron sized LED’s could
therefore communicate 1000x1000(i.e.) million times
as much information as a single 1sq.mm LED.
Thus ,if Li-Fi technology can be put into practical
use, every bulb can be used as an alternative to Wi-Fi
hotspot.
