This document discusses Li-Fi technology, which transmits data through illumination by varying the intensity of LED lights faster than the human eye can perceive. Li-Fi uses visible light communication through LED bulbs as an alternative to Wi-Fi networks. It has advantages over Wi-Fi such as higher speeds of over 1Gbps, stronger security, and less interference. However, Li-Fi requires line of sight between the light source and receiver and does not work through walls. The document outlines the history, working principle, applications and advantages of Li-Fi technology.

1. B.TECH, III YEAR
Department OF
ELECTRONICS & COMMUNICATION
ENGINEERING
LI-FI TECHNOLOGY
Presented By
V.CHANDRA MOULI REDDY & M.THEJ KUMAR

2. CONTENTS...
 Introduction
 What is a Li-Fi technology
 Visible light
 Working Principle
 Overcoming WIFI issues
 Differences b/w Li-Fi & Wi-Fi
 Applications
 Advantages & Disadvantages of Li-Fi
 Conclusion

3. Light Fidelity (Li-Fi) is a bidirectional, high speed
and fully networked wireless communication
technology
similar to Wi-Fi.
 Li-Fi is a subset of optical wireless
communication (OWC) and can be a complement
to RF communication (Wi-Fi).
INTRODUCTION...

4. HISTORY
 Li-Fi is a VLC, visible light communication,
the Technology developed by a scientist Prof.
Herald Haas at the University of Edinburgh.
The term Li-Fi was coined by Prof. Haas in
July 2011.

5. WHAT IS A LI-FI TECHNOLOGY??..
 Li-Fi (Light-Fidelity)
 LI-FI is transmission of data through
illumination, sending data through LED light
bulb that varies intensity faster than human
eye can follow.

6. Li-Fi is a VLC, visible light communication.
It is a technology based on LED’s for the
exchange of data. Data will be sent via light,
ie.; all kinds of light, regardless the part of
spectrum where they belong.
VISIBLE LIGHT...

9. WORKING PRINCIPLE
 If the LED is on, you transmit a digital 1,
 If its off you transmit a digital 0.
 The LEDs can be switched on and off very
quickly, which gives nice opportunities for
transmitting data.
 A controller connected at the back side of these
LEDs is used to code data.
 Thus every light source will works as a hub for
data transmission.

12. LIFI OVER WIFI

13. OVERCOMING WIFI ISSUES
 CAPACITY
 EFFICIENCY
 AVAILABILITY
 SECURITY

14. DIFFERENCE B/W LI-FI,WI-FI...
 Light Fidelity
 Li-Fi transmits data with the
help of LED bulbs.
 Interference is less, can pass
through sea water, works in
high density region.
 About 1Gbps
 About 10m
 Works in high dense
environment.
 Wireless Fidelity
 Wi-Fi transmits data using
radio waves with the help of
Wi-Fi router.
 Interference is more, can not
pass through sea water, works
in less density region.
 150 Mbps
 32m, vary based on transmit
power and antenna type.
 Works in less dense
environment due to
interference related issues.

15. LI-FI TECHNOLOGY:
Used in airlines, Health sector ,undersea
explorations, operation theatres in the office and
home premises for data transfer and internet
browsing.
WI-FI TECHNOLOGY:
Used for internet browsing with the help of
Wi-Fi hotspots.
APPLICATIONS...

16. ADVANTAGES OF LI-FI..
 It is possible to achieve more than 10Gbps
theoretically allowing a high definition film to
be downloaded in 30 sec.
 Mostly powered by LEDs so it is cost
efficient.
 Transmission of data is fast and easy.

17. DISADVANTAGES
Nothing in this world is not perfect and so
does LIFI.
 These signals cannot penetrate walls. So
the person needs wired bulb in that room
also.
 Only works if there is direct line of sight
between source and receiver.

18. CONCLUSION...
 China has become the most advanced country in the sphere
of using Li-Fi in place of Wi-Fi recently. So we can hope that
this new way of connecting via Li-Fi will be here soon. Haas
estimates that the technology be ready for public use within
the next 2-3 years.

19. ANY QUERIES????