A keen and broad explanation on LI-FI technology

1. technology
High speed bidirectional fully
networked wireless
communication.
Project submitted by:
Vinay Kumar Gattu.
KNRR(ECE)

2. Introduction:
 LI-FI is a technology that uses the light emitting
diodes to transmit the data wirelessly.
 LI-FI is fast and cheap optical version of Wi-Fi
,based on visible light communication(VLC).
 VLC is a data communication medium, which uses
the visible light between 400 THz (780 nm) and
800 THz (375 nm) as optical carrier for data
transmission.

3.  By this technology the led bulb having power of
one watt will distribute internet to four systems
at a time.
 The led bulbs having microchips will transmit
internet with speed of 150mbps.

4. Diagrammatic representation of li-fi

5. LI-FI Environment:

6. WHO INVENTED IT ?
 This technology was invented by German physicist
HARALD HAAS , from the University of Edinburgh.
 He demonstrated it in the year 2012.

7. How LI-FI works:

8.  The heart of this technology is a new generation high
brightness LED’S.
 These LED’S varies in intensity (that is gets on and
off) so fast that a human eye cannot detect it.
 If LED is ON , then we transmit logic 1, and if LED is
OFF , then we transmit logic 0.
 A controller is connected at the back side of these
LED bulbs to code data to these LED’S.

9. LI-FI Equipment

10. LI-FI VS WI-FI
 LI-FI has a High speed
data transfer rate over
1gbps.
 Wi-Fi has a data
transfer rate of
maximum 54
mbps.
DATA TRANSFER
SPEED
• Why so much difference?

11. • LI-FI has an upper hand due to parallel data
transmission.

12. Part of EM spectrum they use
LI-FI
 LI-FI uses the
visible light
portion of the EM
spectrum.
WI-FI
 Wi-Fi use the
radio wave portion
of EM spectrum

13. Issues with radio wave:
 Capacity
• With advent of new technologies like 3G, 4G we are
running out of spectrum.
• This is because radio waves are now becoming
expensive.

14.  Efficiency
 There are 1.4 million cellular radio base stations.
 Efficiency of each base station is just 5%.
 Most of the energy is not used for transmission
but rather for cooling down the base station.

15.  Security
• Radio waves can penetrate through walls
and hence can be intercepted.
• Any one with skills of hacking may misuse
it.
 Availability
• We have to switch off mobiles in aircrafts.
• It is not advisable to use mobiles at petrol
bunks.

16. ALTERNATIVE OF RADIO WAVES
CAN IT BE INFRARED WAVES ?
Ir Waves Are Harmful For Our Eyes
Hence Used At Very Low Power

17. CAN IT BE UV RAYS?
• UV rays are harmful for our skin and cannot be used
for long duration.
CAN IT BE GAMMA RAYS ?
Gamma Rays Are Radioactive And Are
Dangerous.
CAN IT BE X-RAYS ? NO
SO WE ARE LEFT ONLY WITH VISIBLE
LIGHT SPECTRUM.

18. Advantages of li-fi which are limitations to
RW
CAPACITY
• 10000 Times More Spectrum Than Rw.
• Light Boxes Are Already Present, So
Infrastructure Is Available Already And
Installed.
EFFICIENCY
Highly Efficient Because Led Consumes
Less Energy.

19. AVAILABLITY
• Light Is Present Everywhere.
• Data is present where light is present.
SECURITY
• Light Waves Does not Penetrate
Through Walls.
• Hence they can’t be intercepted.

20. Advantages of LI-FI
• You Can Use Li-fi In Hospitals And Aircrafts Also.
• Cheaper Then Wi-Fi , Since Visible Light Spectrum Is
A Free Spectrum Band.
• No License Needed.
• Thousands And Millions Of Street Lamps Can Be
Converted To Li-fi Hotspots.

21. IS THIS A PROVEN TECHNOLOGY ?
 Yes This Already Proven.
 HARALD HAAS DEMONSTRATED HIS INVENTION
USING AN ORDINARY TABLE LAMP THAT
SUCCESSFULLY TRANSMITTED DATA AT SPEEDS
EXCEEDING 10mbps USING LIGHT WAVES FORM LED
LIGHT BULBS TO A COMPUTER LOCATED BELOW THE
LAMP. To Prove That The Light Was The Source Of
The Data Stream He Periodically Blocked The Beam
Of Light , Causing The Connection To Drop.