This document discusses Li-Fi, also known as light fidelity. It is a technology that uses visible light communication (VLC) to transmit data wirelessly using LED light bulbs. Some key points: - Li-Fi provides wireless internet access at speeds faster than 10 Mbps by transmitting data through light waves instead of radio waves. - A prototype was able to stream high quality video using a standard LED lamp in 2011. - Li-Fi has advantages over Wi-Fi such as higher speeds up to 500 Mbps, more available spectrum, better security since light cannot pass through walls easily. - Potential applications include underwater communications, internet access anywhere there is light like street lamps, and use in

1. LIGHT FIDELITY OR LI-FI
PRESENTED BY :
JAGRIT VISHWAKARMA
B.TECH CSE

2. Tired of using Slow Speed Wi-Fi Internet ?

3. Can we use other waves instead of Radio waves to surf the Internet?

4. ABSTRACT
• Dr. Herald Haas, German physics, suggested a solution “Data
through Illumination” (i.e. data sending using LED light) in
2004.
• It’s the same idea as Infrared remote control but far more
powerful.
• Data transfer rate will be faster than 10MBPS.
• Security will be high.
• It works on VLC (Visible Light Communication).

5. • In 2011, Dr. Harald Haas was able to build a prototype and was
able to stream a High Quality video by using a standard LED
lamp.
• Li-Fi is now part of the Visible Light Communications (VLC) PAN
IEEE 802.15.7 standard.

6. YES, IT IS
POSSIBLE.
It is possible to transmit Data using Light?

7. INTRODUCTION
• It is a light-based Wi-Fi .
• It uses LIGHT instead of RADIO waves for transmitting
information.
• It is bidirectional, high speed , fully networked wireless
communication.
• It is a subset of Optical Wireless Communication (OWC).

9. • It uses a part of the electromagnetic spectrum that is still not
greatly utilized- The Visible Spectrum.
• Moreover there is 10,000 times more space available in this
spectrum and just counting on the bulbs in use, it also
multiplies to 10,000 times more availability as an
infrastructure, globally.

10. EXISTING WIRELESS TECHNOLOGY - WHY DO WE NEED AN
ALTERNATE TECHNOLOGY?
• Capacity
• Efficiency
• Availability
• Security

11. • 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.
• Haas has set up a spin-off firm to sell a consumer VLC
transmitter that is due for launch next year. It is capable of
transmitting data at 100 MB/s - faster than most UK broadband
connections.

12. VISIBLE SPECTRUM

13. TECH DETAILS
• The main constituent of LI-FI is :
1. An excel brightening white LED which plays the role of a
transmitter.
2. A silicon photodiode with a good response to visible light acts as
a receiver.
• LED’s is switched ON and OFF which produces a chain consisting

14. WORKING OF LI-FI
• An LED lightbulb is a semi-conductor light source meaning that the
constant current of electricity supplied to an LED lightbulb can be
dipped and dimmed, up and down at extremely high speeds, without
being visible to the human eye.
• For example, data is fed into an LED light bulb (with signal
processing technology), it then sends data (embedded in its beam) at
rapid speeds to the photo-detector (photodiode).

15. • The tiny changes in the rapid dimming of LED bulbs is then converted
by the 'receiver' into electrical signal.
• The signal is then converted back into a binary data stream that we
would recognize as web, video and audio applications that run on
internet enables devices.

16. LI-FI VS WI-FI
• Li-Fi signals cannot pass through walls, so in order to enjoy full
connectivity, capable LED bulbs will need to be placed throughout
the home. Not to mention, Li-Fi requires the lightbulb is ON at all
times to provide connectivity, meaning that the lights will need to
be on during the day.
• What's more, where there is a lack of lightbulbs, there is a lack of
Li-Fi internet so Li-Fi does take a hit when it comes to public Wi-Fi
networks.

17. • This new project claims to double the range of connectivity while
using less power. Due to this, Wi-Fi HaLow is reportedly perfect
for battery powered devices such as smartwatches, smartphones
and also on Internet of Things devices such as sensors and smart
applications.
• But it's not all doom and gloom! Due to its impressive speeds, Li-
Fi could make a huge impact on the internet of things too, with
data transferred at much higher levels with even more devices
able to connect to one another.
• What's more, due to its shorter range, Li-Fi is more secure than
Wi-Fi and it's reported that embedded light beams reflected off a

18. APPLICATIONS
• Underwater communications: Since radio waves cannot be used
under water because these waves are strongly absorbed by sea
water and this renders it unusable underwater but LIFI is
suitable for underwater communication
• Health sector: Since WIFI is not safe to be used in hospitals and
other various health care sectors because it penetrates human

19. • Internet anywhere: street lamps, light of vehicles can be used to
access internet anywhere in footpaths, roads, malls, anywhere where
light source is available.
• Safety and management: it can be used to update traffic information
at almost every instant and it will be easy for traffic police to deal
with traffic and catch the one who breaks the rule.
• Navigation System : since visible light is present everywhere, we can
create internal navigation systems for the bigger areas to create
automated machinery/ automatic navigation for the visitors.

21. ANY QUESTIONS?