1. LI-FI TECHNOLOGY

2. INTRODUCTION
Light Fidelity (Li-Fi) is a bidirectional, high-speed and fully networked wireless communication technology similar to Wi-Fi.
LI-FI is a technology that uses the light emitting diodes to transmit the data wirelessly.
LI-FI is fast and cheap practical version of WI-FI, based on visible light communication (VLC).
VLC is a data communication medium, which uses the visible light between 400 Thz (780 nm) and 800 Thz (375 nm) as optical carrier for data transmission

3. PROFESSOR,UNIVERSITY OF EDINBURGH, UK
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.  Harald Haas continues to wow the world with the potential to use light for communication.
HE DEMONSTRATED IT IN THE YEAR
2012.
PROFESSOR,UNIVERSITY OF EDINBURGH, UK

4. Li-fi environment

5. PRESENT SCENARIO Mobile phones transmit 600 TB data every month.
Wireless communication has become an utility like electricity and water.

6. EFFICIENCY RADIO SPECTRUM ISSUES Radiowaves Cost and Expensive
CAPACITY
Radiowaves
Cost and Expensive
Less Bandwidth compared to other spectrums
Insufficient spectrum for increasing data
EFFICIENCY
Millions of base stations consume huge amount of energy for
1.Transmitting the radio waves
2.To cool the base station cabins
5% Efficiency

7. SECURITY RADIO SPECTRUM ISSUES
AVAILABILITY
Available within the range of Base stations
Limited availability
Unavailable in aircrafts
SECURITY
Less secure(passes through the walls)
Anyone with knowledge and bad intention can misuse it

8. Alternative of radio waves

9. WHY ONLY VLC ?? X-rays have similar health issues.
Radio Waves
Infrared Rays
Visible Rays
Ultraviolet Rays
X- Rays
Gama Rays
Gama rays cant be used as they could be dangerous.
X-rays have similar health issues.
Ultraviolet light is good for place without people, but other wise dangerous for the human body
Infrared, due to eye safety regulation, can only be used with low power.
HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

10. Working Process
Operational procedure is very simple, if the led is on, you transmit a digital 1, if its off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. Hence all that us required is some LEDs and a controller that code data into those LEDs. We have to just vary the rate at which the LED’s .
Flicker depending upon the data we want to encode .
Thus every light source will works as a hub for data transmission .

11. LI-FI CONSTRUCTION
The LI FI product consists of 4 primary sub-assemblies:
• Bulb
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure
The high concentration of energy in the electric field vaporizes the contents of the bulb to a plasma state at the bulb’s center; this controlled plasma generates an intense source of light.
2. The PCB controls the electrical inputs and outputs of the lamp and houses the microcontroller used to manage different lamp functions.
An RF (radio-frequency) signal is generated by the solid-state PA and is guided into an electric field about the bulb.
4. All of these subassemblies are contained in an aluminum enclosure

12. How It Works ??
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 the digital data in form of light.
On the other hand, this light is detected by photo sensitive devices.
Next this device is amplified and processed and then fed to the device.

15. APPLICATION AREAS TRAFFIC LIGHTS
Traffic lights can communicate to the car and with each other. Cars have LED-based headlights, LED-based cack lights, and cars can communicate with each other and prevent accidents in by exchanging information.

16. APPLICATION AREAS HOSPITALS
In operation theatre, Li-Fi can be used for modern medical instruments

17. APPLICATION AREAS AIRLINES
Whenever we travel through airways we face the problem in communication media , because the whole airways communication are performed on the basis of radio waves. To overcome this drawback on radiowaves , li-fi is introduced.

18. APPLICATION AREAS INTRINSICALLY SAFE ENVIRONMENT
It can be used in petroleum or chemical plants where other transmission or frequencies could be hazardous.

19. APPLICATION AREAS ON OCEAN BED
Li-Fi can even work underwater were Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.

20. APPLICATION AREAS STREET LAMPS
There are millions of street lamps deployed around the world.
Each of these street lamps could be a free access point.

21. LIMITATIONS 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, and opaque materials in the path of transmission will cause interruption in the communication
A major challenge facing Li-Fi is how the receiving device will transmit back to transmitter.

22. IS IT A PROVEN TECHNOLOGY
Yes, this is already proven.
Dr. Harald has demonstrated his invention using an ordinary table lamp that successfully transmitted data at speed exceeding 10 mbps.
To prove that light bulb was the source of data stream, he periodically blocked the beam of light, causing the connection to drop.

23. FUTURE OF LI-FI

24. In November 2014, Li-Fi pioneers pureLiFi joined forces with French lighting company Lucibel aiming to bring out Li-Fi enables products, by the end of 2015.
pureLiFi already have two products on the market: Li-Flame Ceiling Unit to connect to an LED light fixture and Li-Flame Desktop Unit which connects to a device via USB, both aiming to provide light and connectivity in one device. 
Plus, with faster connectivity and data transmission it’s an interesting space for businesses.

25. Continued..
Li-Fi is reportedly being tested in Dubai, by UAE-based telecommunications provider, du and Zero1. Du claims to have successfully provided internet, audio and video streaming over a Li-Fi connection.
What's more, reports suggest that Apple may build future iPhones with Li-Fi capabilities. A Twitter user found that within its iOS 9.1 code there were references to Li-Fi written as 'LiFi Capability' hinting that Apple may integrate Li-fi with iPhones in the future. 

26. Li-Fi has proven itself as a viable, efficient and secure solution.

27. CONCLUSION Cleaner, Greener, safer and Brighter Future
The possibilities are numerous and can be explored further. If this technology can be put into practical use , every bulb can be used something like a Wi-Fi hotspots to transmit wireless data and we will be proceed onwards the
Cleaner, Greener, safer and Brighter Future

28. Thanks..!!