Light Ray Technology under one room.

1. Presented by:
Naveen Nakka
13765A1007

2. CONTENTS:
• PRESENT WIRELESS COMMUNICATION
• ISSUES REGARDING RADIO SPECTRUM
• WHAT IS Li-Fi
• WORKING &BLOCK DIAGRAM
• TRANSMITTING & RECEIVING ELEMENTS
• COMPARISION BETWEEN Wi-Fi AND Li-Fi
• ADVANTAGES & DIS-ADVANTAGES
• APPLICATIONS
• CONCLUSION

3. PRESENT WIRELESS
COMMUNICATION
• Radio spectrum
• 1.4 Million base stations, 5 billion Mobile stations
• 600TB data every month

4. • Cost and Expensive.
• Less Bandwidth compared to other spectrums.
• Insufficient spectrum for increasing data.
• Millions of base stations consume huge amount of energy for
1.Transmitting the radio waves.
2.To cool the base station cabins
• Unavailable in aircrafts.
• Less secure(passes through the walls)
ISSUES REGARDING RADIO SPECTRUM

5. Is not used
generally
Used
for
hospital
s
Dangerou
s for
human
body
Which is not used so far
Safe to use
Larger bandwidth
Expensive,
Limited BW
Less Secure
Low power
Applications

6. WHAT IS LI-FI....?
Light Fidelity (li-fi). It is a simple, cost-effective way to
connect to the Internet. It minimizes the need for long cables
running from one end of the room to the other or from floor to
floor. At the heart of this technology is a light-emitting diodes It
is possible to encode data in the light by varying the rate at
which the LEDs flicker on and off to give different strings of 1s
and 0s. The flicker depending upon the data we want to encode.
If the LED is on, you transmit a digital 1, if it’s off you transmit
a 0. The LED bulb will hold a micro-chip that will do the job of
processing the data.

7. LI-FI works with the help of Light basically LED’s and
fluorescent lamps. The LEDs can be switched on and off very
quickly, which gives nice opportunities for transmitting data.
So what you require at all are some LEDs and a controller
that code data into those LEDs. Li-Fi technology is mainly
based on LEDs for the transfer of data. The transfer of the
data can be with the help of all kind of light i.e Light may be
Invisible, Ultraviolet or Visible part of spectrum.
WORKING:

8. The basic principle here is modulation and de-modulation,
the signal is modulated with the help of carrier signal here the
carrier signal is light and the modulated signal is transferred
through LED and it is detected by photo diodes here the
modulated signal is de-modulated to get the modulating
signal i.e. signal containing information.
Internet from the server is fed to the LED through the lamp
driver circuit the LED flickers according to the signal i.e. if it
is on, you transmit a digital 1, if it’s off you transmit a 0. The
flickering of LED is detected by photo sensors (photo diodes)
are used. Therefore it is amplified to get the transferred
signal.

10. BLOCK DIAGRAM
Data Modulation
Light
Source
Data
Demodulatio
n
Photo
Detector

12. TRANSMITTING ELEMENT
• Normally transmitting elements are LED.
• Fluorescent Lamp

13. RECEIVING ELEMENT
(DETECTOR)
• Photo Diode
• Image Sensors

14. Li-fi USB Key designed
by for tablet
Li-Fi router for PC
Li-Fi Dongle for Smartphones.

15. LI-FI is a term of one used to describe visible light
communication technology applied to high speed wireless
communication. It acquired this name due to the similarity to
WI-FI, only using light instead of radio.WI-FI is great for
general wireless coverage within buildings, and li-fi is ideal
for high density wireless data coverage in confined area and
for relieving radio interference issues, so the two
technologies can be considered complimentary.
COMPARISION BETWEEN Li-Fi &
Wi-Fi

16. ADVANTAGES
• It is possible to achieve more than 10Gbps, theoretically
allowing a high-definition film to be downloaded in 30sec.
• Mostly powered by LEDs so cost is low.
• Transmission of data is fast and easy.
• Its main advantage is it’s Bandwidth is 10,000 times than the
radio waves.

17. DISADVANTAGES
• Presence of light is required.
• There should be line of sight.
• Works better with fluorescent light and LEDs but very low
efficiency with Bulbs.
• shadowing

18. APPLICATIONS
• Used for modern medical instruments.
• Used in petroleum or chemical plants
• where other transmission or frequencies could be hazardous..
• In Aircrafts.

19. IN RF RESTRICTED
ENVIRONMENTS

20. HOSPITALS(IN FEW MEDICAL
INSTRUMENTS)

21. IN AIRCRAFT CABINS

22. UNDER THE OCEAN

23. CONCLUSION:
The concept of Li-Fi is currently attracting
because it may offer a genuine and efficient
alternative to radio-based wireless. As a
growing number of people and their devices
access wireless internet, the air waves are
becoming clogged, making it more and more
difficult to get a reliable, high-speed signal. So
Li-Fi has a bright future.

25. ANY QUERIES?????!!!!!!!!!!!