this is the presentation on lifi technology

1.  Presented by
 Sachin gupta
 Cs 3rd year
 1300110044

2. What is LI-FI
 Li-Fi can be thought of as a light-based Wi-Fi. That
is, it uses light instead of radio waves to transmit
information.
 And instead of Wi-Fi modems, Li-Fi would use
transceiver-fitted LED lamps that can light a room
as well as transmit and receive information.

3.  LI-FI is transmission of data through illumination
,ie sending data through a LED light bulb that varies
in intensity faster than human eye can follow
 LI-FI stands for LIGHT FIDEALITY

5. HISTORY
 Prof. Harald Hass is widely recognized
as the founder of the Li-Fi
 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 Prof. Harald Hass

6. on 12th July 2011. He used a table lamp with an LED bulb to
transmit a video of blooming flowers that was then projected onto
a screen behind him. During the event he periodically blocked the
light from lamp to prove that the lamp was indeed the source of
incoming data.
At TEDGlobal, Haas demonstrated a data rate of transmission of
around 10Mbps -- comparable to a fairly good UK broadband
connection. Two months later he achieved 123Mbps.
Back in 2011 German scientists succeeded in creating an800Mbps
(Megabits per second) capable wireless network by using nothing
more than normal red, blue, green and yellow.

7. WHO CAN REPLACE THE
RADIO WAVES FOR
WIRELESS
COMMUNICATION ?

10. HOWLi-Fi WORKS
 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.
The operational procedure is very simple-, if the LED is on, you
transmit a digital 1, if it’s off you transmit a 0. The LEDs can be
switched on and off very quickly, which gives nice opportunities for
transmitting data

11.  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
 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

12.  A light sensitive device (photo detector) receives the signal and
converts it back into original data. This method of using rapid
pulses of light to transmit information wirelessly is technically
referred as Visible Light Communication
 Further enhancements can be made in this method, like using an
array of LEDs for parallel data transmission, or using mixtures of
red, green and blue LEDs to alter the light‘s frequency with each
frequency encoding a different data channel. Such advancements
promise a theoretical speed of 10 Gbps – meaning one can
download a full high-definition film in just 30 seconds

13. Forgiga-speedtechnologies,theLi-FiConsortiumdefined GigaShower,GigaSpot
andGigaMIMOmodels

14. THE GIGA SHOWER
WHATIT IS
- Ceiling unit sends up to 10Gbit/s stream
- IR receivers plug into mobile devices
WHATIT DOES
- Delivers up to10 Gbit/s across many users
- Each user can have separate channels
- Receivers can be wide-angle tolerant
WHATIT IS FOR
- Broadcasting large volume of data
(e.g. audio and video)
- Public areas or meeting rooms

15. THEGIGA MEMO
WHATIT IS
- Ceiling unit steers multiple beams
- Receivers point beam back up
WHATIT DOES
- Many bidirectional high speed links
- Delivers 10 Gbit/s to each user
- Beams track user movement
- Mobile indoor communication
WHATIT IS FOR
- Many simultaneous users

16. LI-FI VSWI-FI
SNO. PARAMETERS WIRELESSTECHNOLOGY
LI-FI WI-FI
1 SPEED Faster transfer speed
(> 1 gbps)
Data transfer speed
(150 mbps)
2 Medium Used light as the carrier Used radio spectrum
3 Spectrum range Visible light spectrum has
10000 broad spectrum in
comparison to the radio
spectrum
Radio frequency spectrum
range is less then the visible
light spectrum
4 Cost Cheaper Expensive
5 Operating frequency Hundreds of tera Hz 2.4 GHz

18. APPLICATIONOF LI-FI
Li Fi technology is still in its infancy .However some areas
where it seems perfectly applicable are:-
TRAFFIC LIGHT
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.

20. INTRINSICALLY SAFE ENVIRONMENT
Visible Light is more safe than RF, hence it can be used in places
where RF can't be used such as petrochemical plants .

21. 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 overcomes this drawback on radiowaves, li-fi is introduced.

24. LIMITATIONS OR CHALLENGES
light can't pass through objects
Interferences from external light sources like sun light, normal
bulbs, and opaque materials in the path of transmission will
cause interruption in the communication.
High installation cost of the VLC systems
A major challenge facing Li-Fi is how the receiving device will
transmit back to transmitter.

25. CONCLUSION
The possibilities are numerous and can be explored further. If
this technology put into practical use, every bulb can used
something like a WI-FI hotspot to transmit wireless data

26. THANK YOU FOR YOUR
TIME 
ANY QUERIES