li-fi technology - thesis scientist · pdf fileintroduction •light fidelity (li-fi) is a...
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INTRODUCTION• Light Fidelity (Li-Fi) is a bidirectional, high-speedand fully networked wireless communicationtechnology similar to Wi-Fi.
• LI-FI is a technology that uses the light emittingdiodes 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 usesthe visible light between 400 Thz (780 nm) and 800Thz (375 nm) as optical carrier for data transmission
HistoryThe 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 YEAR2012.
PROFESSOR,UNIVERSITY OF
EDINBURGH, UK
“Mobile phones transmit 600 TB data every month.
Wireless communication has become an utility like electricity and water.
PRESENT SCENARIO
RADIO SPECTRUM ISSUES
◎ 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
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
WHY ONLY VLC ??
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.
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 .
Working Process
LI-FI CONSTRUCTIONThe LI FI product consists of 4 primary sub-assemblies:
• Bulb
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure
1. 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.
3. 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
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.
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.
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.
APPLICATION AREAS
◎INTRINSICALLY SAFE ENVIRONMENT
It can be used in petroleum or chemical plants where other transmission or frequencies could be hazardous.
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.
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.
LIMITATIONS
There should be line of sight between senderand receiver
Visible light cannot penetrate through solidobjects
High installation cost of the VLC systems
Interferences from external light sources likesun light, normal bulbs, and opaque materials inthe path of transmission will cause interruption inthe communication
A major challenge facing Li-Fi is how thereceiving device will transmit back to transmitter.
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.
“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.
“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.
CONCLUSION
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