Li-Fi is transmission of data through illumination by taking thefiber out of fiber optics by sending data through a LED lightbulb that varies in intensity faster than the human eye canfollow. “At the heart of this technology is a newgeneration of high brightness light-emitting diodes”, saysHarald Haas from the University of Edinburgh, UK.”Verysimply, if the LED is on, you transmit a digital 1, if it’s offyou transmit a 0,”Haas says, “They can be switched on and offvery quickly, which gives nice opportunities for transmitteddata.” It is possible to encode data in the light by varying therate at which the LEDs flicker on and off to give differentstrings of 1s and 0s.The LED intensity is modulated so rapidlythat human eye cannot notice, so the output appears constant. More sophisticated techniques could dramatically increaseVLC data rate. Terms at the University of Oxford and theUniversity of Edinburgh are focusing on parallel datatransmission using array of LEDs, where each LED transmits a different data stream. Other groups are using mixtures of red,green and blue LEDs to alter the light frequency encoding adifferent data channel. Li-Fi, as it has been dubbed, has alreadyachieved blisteringly high speed in the lab. Researchers at theHeinrich Hertz Institute in Berlin, Germany have reached datarates of over 500 megabytes per second using a standardwhite-light LED. Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. This very property of optical current is used in Li-Fi setup.The operational procedure is very simple-,data from the internet and local network is used to modulate the intensity of the LED light source if any undetectable to the human eye. The photo detector picks up signal, which is converted back into a data stream and sent to the client. The client can communicate through its own LED output or over the existing network. An overhead lamp fitted with an LED with signal-processing technology streams data embedded in its beam at ultra-high speeds to the photo-detector. A receiver dongle then converts the tiny changes in amplitude into an electrical signal, which is then converted back into a data stream and transmitted to a computer or mobile device.

1. Li-Fi Technology
By
Vivek kumar jha
Reg no- 1001215240
branch- CSE

2. Contents
 Abstract
 Introduction
 Drawbacks Of Before Technologies
 Different Between The Technologies
 Working process
 Applications
 Advantages
 Conclusion

3. Abstract
One germen phycist. Harald Haas has come up with
a solution he calls “data through illumination” –taking the
fibber out of fibber optic by sending data through an LED
light bulb that varies in intensity faster than the human eye
can follow. It’s the same idea band behind infrared remote
controls but far more powerful. Haas says his
invention, which he calls D- LIGHT, can produce data rates
faster than 10 megabits per second, which is speedier than
your average broadband connection.

4. Introduction
Li-Fi means “Light Fidelity”.
At the heart of this technology is a new
generation of high brightness 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.

5. Drawbacks Of Before Technologies

6. Availability
Capacity
Efficiency
Security

9. Different Between The Technologies

10. Working process
LIFI offers an integrated light source that is straightforward to integrate into a projector. In this example
LIFI consists of 5 primary sub-assemblies:




Printed circuit board (PCB)
RF power amplifier (PA)
Bulb
Optics
 Enclosure

12. Applications
Capacity
Availability
Efficiency
Security

14. Advantages
High Security
Easy To Use
Fast Data Transfer
Reliable
Harmless ness
Low Cost

15. Conclusion
The possibilities are numerous and can be explored further.
If his technology can be put into practical use, every bulb can be
used something like a Wi-Fi hotspot to transmit wireless data and
we will proceed toward the cleaner, greener, safer and brighter
future.

16. Reference
http://www.ted.com/talks/harald_haas_w
ireless_data_from_every_light_bulb.html
http://marginalrevolution.com/marginalrevo
lution/2011/08/new-wireless-technologieslifi-and-dido.html

17. Any Queries ?