This document discusses Li-Fi technology, which uses visible light communication to transmit data wirelessly using LED light bulbs. Li-Fi was coined by Professor Harald Haas as an alternative to Wi-Fi that uses radio frequencies. It provides bidirectional and fully networked wireless connections at high speeds. Potential practical uses of Li-Fi include use in traffic lights, hospitals, airplanes, and underwater communications. Compared to Wi-Fi, Li-Fi has benefits like higher speed and more secure communication, but also faces limitations such as inability to pass through solid objects and interference from other light sources. Future developments could allow Li-Fi to still function in daylight and at night by modulating light intensity.

1. Li-Fi Technology

2. 2
Submitted to
Nahar Sultana
Assistant Professor,
Department of Computer Science
American International University-Bangladesh
Submitted by
1. CHAKMA, JYOTI BASU 15-28558-1
2. IQBAL, ASIF 15-28730-1
3. RUMEL, ABU HUMAYED 15-28983-1
4. KHAN, MD. TASDIKUL ISLAM 15-29210-1
5. MAZBA, AL NOOR TURZA 15-29250-1

3. Motivation
3
 20 billion IoT devices by the year 2020
 Wi-Fi uses radio frequencies
 Internet everywhere

4. Contents
◇ Introduction
◇ Background
◇ Working Principles
◇ Practical Uses
◇ Li-Fi vs Wi-Fi
◇ Limitations
◇ Future Possibilities
◇ Conclusion
◇ References
4

5. Introduction
 Light Fidelity (Li-Fi) is a bidirectional, high-speed and
fully networked wireless communication technology.
 Li-Fi is transmission of data through illumination,
sending data through a LED light bulb that varies
intensity faster than human eye can follow.
 It is wireless and uses visible-light communication or
infrared and near-ultraviolet instead of radiofrequency
spectrum, part of optical wireless communications
technology.
1

6. Background
The technology truly began
during the 1990's in
countries like Germany,
Korea and Japan where
they discovered LED's
could be retrofitted to send
information. Li-Fi coined by
Prof. Harald Haas during
his TED Global talk, is
bidirectional, high speed
and fully networked
wireless communications
similar to Wi-Fi.
2
Prof. Harald Haas
University of Edinburgh

7. Working Principles
3

8. Practical Uses
 Traffic Lights:
Traffic lights can
communicate to
the car and with
each other. Cars
have LED based
headlights. Cars
can communicate
with each other
& and prevent
accidents in by
exchanging
information.
4

9. Practical Uses
 Health sector: Since WI-FI is not safe to be used in
hospitals and other various health care sectors because
it penetrates human body. Li-Fi can be implemented
and well suit in this sector.
4

10. Practical Uses
 Airlines: Whenever
we travel through
airways we face
the problem in
communication
media because the
whole airways
communication
are performed on
the basis of radio
waves. To
overcome this
drawback, Li-Fi is
introduced.
4

11. Practical Uses
 Underwater communications: Since radio waves cannot
be used under water because these waves are strongly
absorbed by sea water within feet of their transmission
and this renders it unusable underwater but Li-Fi is
suitable for underwater communication.
4

12. Practical Uses
 Internet
anywhere: street
lamps, light of
vehicles can be
used to access
internet
anywhere in
footpaths,
roads, malls,
anywhere where
light source is
available.
4

13. Li-Fi vs Wi-Fi
 Carrier
 Cost
 Frequency
 Health Issues
 Range
 Security
 Speed
5

14. Limitations
 Light cannot pass through objects.
 Interferences from external light sources.
 Li-Fi range is limited.
 High installation cost of the VLC systems.
 Light should be always on which is disturbing to
eyes.
6

15. Future Possibilities
 Modulated light can still be detected in daylight.
 Intensity of the light can be changed at night.
7

16. Conclusions
The possibilities are numerous and can be explored further. If this
technology can be put into practical use, every bulb can be used
something like a Wi-Fi hotspots to transmit wireless data.
8

17. References
 https://www.lifi.eng.ed.ac.uk/
 https://purelifi.com/technology/
 http://www.lighting.philips.com/main/products/lifi
 https://www.fastcompany.com/90164732/what-
is-li-fi-the-new-alternative-to-wi-fi
 https://www.techworld.com/data/what-is-li-fi-
everything-you-need-know-3632764/
 http://www.rfwireless-
world.com/Terminology/What-is-Solar-LiFi.html
9

18. Thanks!
Any questions?
18