this is ppt on lifi technology....describing meaning, working , construction , application , merits/demerits etc. of lifi technology.

1. GURU TEGH BAHADUR
INSTITUTE OF TECHNOLOGY
Presented By:
GAGANDEEP SINGH
04213202811
E.C.E.-1
Seminar Presentation On:
Li-Fi Technology in Wireless
Communication

2.  Introduction
 History
 Present Technology
 Why Only VLC
 Working Process Of Li-fi
 Architecture Of Li-fi
 Li-fi Environment
 Li-fi Construction
 Model Prototype Of Li-fi
 Difference Between The Technologies
 Applications
 Advantages Of Li-fi
 Limitations Of Li-fi
 Conclusion
 Refrences

3.  Li-fi stands for light fidelity and li-fi is transmission technology of
data through illumination sending data through a led light bulb that
varies in intensity faster than human eye can follow
 Li-fi is a technology that uses the light emitting diodes to transmit
the data wirelessly.
 Led lights can be switched on and off at high speeds. This property
is the basics for li-fi. Led when on gives binary 1 and it off gives
binary 0.
 Li-fi is fast and cheap optical version of wi-fi based on visible light
communication (vlc).
 Vlc is a data communication medium,which uses the visible light
between 400 thz to 800 thz (375 nm) as optical carrier for data
transmission.

4.  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.
 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.
 He envisions a future where data for
laptops and other mobile devices is
transmitted through a light in a room.
HARALD HASS

5. 1.4 Million 5 Billion

6.  Radio Spectrum is congested but the demand for wireless
data double each year .Every thing, it seems want to use
wireless data but the capacity is drying up.
 So what can carry this excess demand in the future .
 1.4 Million base stations, 5 billion Mobile stations
 600tb data every month
 Major issues with radio waves are capacity , efficiency,
availibility and security.

9.  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 bse used with
low power.
 We have already seen the short comings of radio waves.
HENCE WE LEFT WITH ONLY THE VISIBLE -
LIGHT SPECTRUM.
Radio-
Waves
Infra-
Waves
Visible
Rays
Ultra-
Violet
X-rays
Gamma
Rays

10. Operational procedure is very simple, LED ie Light emitting diode can be
switched on and off faster since operating speed of LED is less than 1 μs, than
the human eye can detect, causing the light source to be appear continuously.
This invisible on-off activity enables a kind of data transmission using binary
codes. Switching on and LED is a logical ‘1’, switching it off is a logical ‘0’.It
is possible to encode data in the light by varying the rate at which LED’s
flicker on and off to give different strings of 1s and 0s. Modulation is so fast
that human eye doesn’t notice.
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.

13. The LiFi 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.

16.  Can be used in the places where it is
difficult to lay the optical fiber like
hospitals. In operation theatre Li-Fi
can be used for modern medical
instruments.
 Li-Fi can even wok underwater
were Wi-Fi fails completely, thereby
throwing open endless opportunities
for military/navigation operations.
 In traffic signals Li-Fi can be used
which will communicate with the
LED lights of the cars and accident
numbers can be decreased.
 Thousands and millions of
street lamps can be
transferred to Li-Fi lamps
to transfer data.

17.  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.In
aircraft Li-Fi can be used to
transmit data.
 Visible Light is more safe
than RF, hence it can be
used in places where RF
can't be used such as
petrochemical plants

18. CAPACITY
 10000times more spectrum than Radio waves.
 Light box are already present.
 We have the infrastructure available and already
installed.
EFFICIENCY
 Data through illumination and thus data transmission
comes for free.
 Led light consumes less energy.
 High efficient.

19. AVAILABILITY
 Light is present everywhere.
 Can be used in airplanes.
 It can be underwater where radio waves cannot.
SECURITY
 Light waves doesn’t penetrate through walls.
 Can’t be intercepted and misused.
 Data is present where there is light.

20.  There should be line of sight between sender and receiver
 Visible light cannot penetrate through solid objects
 Interference with other electromagnetic waves makes the
transmitting data to distort
 Light cannot approach the range and penetration of radio waves
 High installation cost of the VLC systems
 A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.
 Interferences from external light sources like sun light, normal
bulbs, and opaque materials in the path of transmission will cause
interruption in the communication.

21. 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 Wi-Fi
hotspot to transmit wireless data and we will proceed
onwards the
Cleaner, Greener, Safer and Brighter future.

22. 1. http://www.electronicsforu.com/electronicsfo
ru/circuitarchives/view_article.asp?sno=778&title%20=%2
0lifi%3a+a+new+paradigm+in+wireless+communication&
b_type=new&id=12042
2. lificonsortium.org
3. http://en.wikipedia.org/wiki/li-fi
4. ebookbrowse.com/an002-instrumentlighting-pdf-d20428293
5. international journal of advances in computing &
communications, vol 1, 2013,page
no-12 www.ijacc.org
6. purevlc.com

23. GAGANDEEP SINGH
En. Roll. :04213202811
Serial No. : 039
(ECE-1)