Li-fi-The future technology in Wireless Communication

1. TECHNICAL SEMINAR ON
LI-FI(LIGHT FIDELITY)
By
G.N.V.S. SAI KIRAN(10AG1A0441)
Under the Guidance Of:
Asst Prof. Y.V.S. DURGA PRASAD

2.  Present Scenario
 Issues regarding Radio spectrum
 History
 Demonstration
 Introduction
 Working
 Construction
 Applications
 Advantages
 Challenges
 Conclusion
CONTENTS

3. •72 hours of video are uploaded to YouTube
every minute
•25% of global YouTube views come from
mobile devices
•Internet video traffic is growing at 48%
CAGR
•Mobile phones transmit 600TB of data
every month
•Wireless communication has become an
utility like electricity and water
PRESENT SCENARIO

4. LEADING TO RF SPECTRUM SHORTAGE

5. ISSUES REGARDING RADIO SPECTRUM

6. CAPACITY:
 With the increasing number of mobile subscribers the
spectrum is getting congested.
EFFICIENCY:
 The data speeds can only reach up to a few hundreds of
megabits per second.
AVAILABILITY:
 The availability of the radio waves is yet another major
issue.
SECURITY:
 These radio waves can easily penetrate through the
walls, thus letting anonymous users to use the network.

7. HOW TO FIX THE PROBLEM?

8. HISTORY
 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.
 A German physicist Dr. Harald
Haas, has started working on
transmission of data using visible
light back in 2004.
 In the year 2011 he first
introduced to the world this new
technology,LI-FI in the TED talk
show.

9. DEMONSTRATION

10. INTRODUCTION
 Li-Fi is transmission of data through illumination
sending data through a LED light bulb that switches
faster than human eye can follow.
 This invisible on-off activity enables a kind of data
transmission using binary codes, switching on LED is
a logical ‘1’, switching it off is a logical ‘0’.
 Li-Fi is a VLC, visible light communication, which uses
the visible light between 400 THz (780 nm) and 800
THz (375 nm) as optical carrier for data transmission.

11. WHY ONLY VLC ?
 Gamma rays are dangerous and thus can’t be used for
our purpose of communication.
 X-rays are good in hospitals and can’t be used either.
 Ultra violet rays are sometimes good for our skin but for
long duration it is dangerous.
 Infrared rays are bad for our eyes and are therefore
used at low power levels.
 We have already seen the short comings of radio
waves.
 So we are left with Visible light.
Radio-
Waves
Infra-
Waves
Visible
Rays
Ultra-
Violet
X-rays
Gamma
Rays

12. WORKING
• On one end all the data on the
internet will be streamed to a
lamp driver.
• When the LED is turned on the
microchip converts this digital
data in the form of light.
• On the other end this light is
detected by photo sensitive
devices.
• Next this light is amplified and
processed and then fed to the
device.

13. CONSTRUCTION
The Li-Fi chip consists of 4 primary
sub-assemblies:
• Bulb
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure
 The PCB controls the electrical inputs and outputs of the
lamp.
 An RF (radio-frequency) signal is generated by the PA is
guided into an electric field about the bulb vaporizes the
contents of the bulb to a plasma state and generates an
intense source of light.

14. PROTOTYPE OF LI-FI

15. INTRINSICALLY SAFE ENVIRONMENT
Applications

16. IN VEHICLES AND TRAFFIC LIGHTS

17. PUBLIC INTERNET HOTSPOTS

18. IN AIRCRAFT CABINS

19. Hospitals(In few medical instruments)

20. ADVANTAGES
 Visible light spectrum is 10000 times more compared to
radio wave spectrum
 The data transmission can reach up to gigabits per
second thus providing very rich data streaming.
 The sources can be used as normal lights when there is
no data transmission

21. • There should be line of sight between sender
and receiver
• Visible light cannot penetrate through solid
objects
• High installation cost of the VLC systems
• Interferences from external light sources like
sun light, normal bulbs, in the path of
transmission will cause data to distort
CHALLENGES

22. CONCLUSION
 If this technology can be put into practical use, every light
source can be used like a Wi-Fi hotspot to transmit data.
 Li-Fi cannot wipe off the need of Wi-Fi.
 Li-Fi is complementary.