Li fi technology PPT

1. Powerpoint Templates
Page 1
PRESENTED BY
SURA TEJA, 14281A0456
ELECTRONICS AND
COMMUNICATIONENGINEERING

2. Powerpoint Templates
Page 2
• Introduction
• What is Wi-Fi ???
• Issues regarding Wi-Fi (Radio Spectrum)
• What is Li-Fi???
• Principle of Li-Fi Technology
• Visible Light Communication
• Construction and Working of Li-Fi
• Comparison between Wi-Fi and Li-Fi
• Future Applications of Li-Fi
• Advantages and Disadvantages
• Conclusion
• References
CONTENTS

3. Powerpoint Templates
Page 3
WHAT IS Wi-Fi??
WHAT IS
Wi-Fi ???

4. Powerpoint Templates
Page 4

5. Powerpoint Templates
Page 5

6. Powerpoint Templates
Page 6
LI-FI

7. Powerpoint Templates
Page 7
Li-Fi (LighT FidELiTy)
• Li-Fi (Light Fidelity )can be thought of as a light-based Wi-Fi.
• Technology uses The Visible Spectrum
• The term was first used by Harald Haas in his TED Global talk
on Visible Light Communication in 2011
• In October 2011 a number of companies and industry groups
formed the Li-Fi consortium, to promote high-speed optical
wireless systems.
• Researchers at the Heinrich Hertz Institute in Berlin,
Germany, have reached data rates of over 500 megabytes per
second using a standard white-light LED.

8. Powerpoint Templates
Page 8
LI-FI ENVIRONMENT

9. Powerpoint Templates
Page 9
PRINCIPLE OF LI-FI
TECHNOLOGY
• The heart of this technology is a new generation high
brightness led’s.
• Visible Light Communication.
• 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 a digital signal 1,and if the
led is off , then we transmit a digital signal 0.
• A controller is connected at the back side of these led
bulbs to code data to these led’s.

10. Powerpoint Templates
Page 10
If led is on , then we transmit a digital signal 1,
and if the led is off , then we transmit a digital signal 0.

11. Powerpoint Templates
Page 11
VISIBLE LIGHT COMMUNICATION
ж Li-Fi is a faster and cheaper version of Wi-
Fi, which is based on visible light
communication (VLC).
ж The visible light communication is a data
communication technique using visible light
between 400 THz and 800 THz as an optical
carrier for data transmission.

12. Powerpoint Templates
Page 12
WHY VLC???

13. Powerpoint Templates
Page 13
ж Gama rays,X-rays,Ultraviolet rays are harmful for the human
body.
ж Infrared rays are also dangerous, due to eye safety
regulation, and can only be used with low power.
ж Radio waves are expensive and they are less secure.
ж Hence we are left with only the VISIBLE - LIGHT
SPECTRUM which is not harmful for humans .

14. Powerpoint Templates
Page 14
CONSTRUCTION AND WORKING OF LI-FI

15. Powerpoint Templates
Page 15
CONSTRUCTION aNd WORKING OF LI-FI (CONTI..)
ж Li-Fi is implemented using white LED light bulbs at
downlink transmitter.
ж By fast variations of the current, optical output can be made
to vary at extremely high speeds.
ж An overhead lamp fitted with an LED with signal processing
technology streams data embedded in its beam at ultra high
speeds to the photodiodes.
ж A receiver dongle then converts the tiny changes in
amplitude into an electrical signal, which is then converted
back into a data stream & transmitted to a computer or
mobile device.

16. Sl.No Parameters Light Fidelity Wireless Fidelity
1 Speed for data transfer Faster transfer speed (>1 Gbps) Data Transfer speed (150 Mbps)
2 Medium through which
data transfers occurs
Used Light as a carrier Used Radio spectrum
3 Spectrum Range Visible light spectrum has 10,000
time
broad spectrum in comparison to
radio frequency
Radio frequency spectrum range
is
less than visible light spectrum.
4 Cost Cheaper than Wi-Fi because free
band
doesn’t need license and it use light.
Expensive in comparison to Li-Fi
because its uses radio spectrum.
5 Network topology Point to point Point to point
6 Operating frequency Hundreds of Tera Hz (THz) 2.4 GHz
COMPaRISON BETWEEN LI-FI aNd WI-FI

17. In vehicles and traffic lights, reducing accidents
and traffic congestion

19.  Hospitals

20.  Street lamps(as free access points)

21.  Petroleum and chemical industries

23. •Light can't pass through objects.
•A major challenge facing Li-Fi is
how the receiving device will transmit
back to transmitter.
•High installation cost of the VLC systems
•Interferences from external light sources like
sun , light , normal bulbs , opaque materials .

24.  The possibilities are numerous and can be
explored further.
 In spite of disadvantages if this 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.

25.  Websites:
 1: http://timesofindia.indiatimes.com/home/science/Now-
just-light-a-bulb-to- switch-on-your-broadband/article
show/9713554.cms

 2: http://oledcomm.com/lifi.html

 3: http://en.wikipedia.org/wiki/Li-Fi

 4: http://slideshare.com/li-fitech.html