The document discusses Li-Fi technology, which uses visible light communication (VLC) to transmit data wirelessly using LED light bulbs and photodetectors. It notes that radio spectrum is becoming congested as wireless data usage increases, while visible light spectrum is vastly larger. Li-Fi provides higher speeds and more available bandwidth than traditional Wi-Fi. The document outlines how Li-Fi works and its potential applications, benefits over other technologies, and addresses some common misconceptions about Li-Fi.

1. Presentation
Seminar on Li-Fi
Technology
The future technology in
wireless communications
Sumedh Saraf
338/10
52

2. General network scenario
Whether you are using a wireless internet in
a coffee shop or mall, competing for
bandwidth at a conference or probably
stealing it from the guy next door, you
often get frustrated because of the low
speeds you face.

3. Present Scenario
1.4 Million
5 Billion

4. Present Scenario
Radio Spectrum is congested but the
demand for wireless data doubles each
year .Every thing, it seems want to use
wireless data but the capacity is drying up.

5. Issues with radio waves and
why should we use Visible Light
for Communication

6. CAPACITY:
CAPACITY:
With the increasing number
of mobile connections the
availability of the spectrum is
getting congested.
Light is a readily available
form of energy and it covers
the major portion of the EM
spectrum.
Radio waves form only a
small fraction of the entire EM
spectrum thus making the
problem even worse.
Visible light spectrum is
10000 times more
compared to radio wave
spectrum.

7. EFFICIENCY:
EFFICIENCY:
For every unit of energy
consumed the data
transmitted is relatively less.
The data transmission for a
unit energy consumption is
high in the case of light
waves.
The data speeds in the
current system can only
reach up to a few hundreds
of megabits per second.
The data transmission can
reach up to gigabits per
second thus providing very
rich data streaming.

8. AVAILABILITY:
AVAILABILITY:
The availability of the radio
waves is yet another major
issue now a days.
Light is readily available in
every part of the world.
These waves are not much
available during the flight
travel.
This makes it easy for people
in airplanes to work on the
internet.

9. SECURITY:
SECURITY:
These radio waves can easily
penetrate through the walls,
thus letting anonymous users
to use the network.
Unlike radio waves light
waves cannot penetrate
through opaque objects thus
providing plenty of network
privacy.
This can pose threat if the
people with bad intentions
start using it.
No other person can share a
network unless the owner has
permitted them to use it.

10. ECONOMIC:
ECONOMIC:
Due to the limited
availability of the radio
waves the tariff rates are
relatively costlier.
The tariff rates can be very
cheap as light waves are a
cheap resource.
There can be many
transparency issues during
the spectrum allocations
paving way for many scams
like in the case of 2G.
There can be transparency
in spectrum allocations due
to its cheapness.

11. WHY ONLY VLC
Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays
X- Rays
Gamma
Rays
CAN IT BE GAMMA RAYS ? NO
GAMMA RAYS ARE RADIOACTIVE AND DANGEROUS FOR HEALTH.
CAN IT BE X-RAYS ? NO
X-RAYS HAVE SIMILAR HEALTH ISSUES
CAN IT BE UV RAYS? NO
UV RAYS ARE HARMFUL FOR OUR SKIN AND CANNOT BE USED FOR
LONG DURATION

12. CAN IT BE INFRARED WAVES ? NO
INFRARED, DUE TO EYE SAFETY REGULATION, CAN ONLY BE USED
WITH LOW POWER.
HENCE WE ARE LEFT WITH ONLY THE VISIBLE - LIGHT
SPECTRUM.

13. How can we utilize the
benefits offered by the
visible spectrum?
Li-Fi
(Light Fidelity)

14. Introduction of Li-Fi
 Li-Fi
is a VLC technology developed by Dr.
Gordon Povey, Prof. Harald Haas and Dr.
Mostafa Afghani.
 Li-Fi is now a part of the Visible Light
Communications(VLC) PAN IEEE 802.15.7
standard
 These devices are normally used for
illumination by applying constant current
through the LED

15. Working of Li-Fi
 This
brilliant idea was first showcased in a
TED Global talk on VLC.
 Switching
the LEDs ON and OFF gives nice
opportunities for transmitting data
 Some
LEDs and a controller that can
code data into those LEDs.

16.  Usage
of an array of LEDs for parallel data
transmission, or using mixtures of
red, green and blue LEDs to alter the
light’s frequency.
 Theoretical
 Usage
speed of 10 Gbps
of rapid pulses of light to transmit
information wirelessly

19. A LI-FI ENVIRONMENT

20. Comparison between current
and future technologies

21. POTENTIAL APPLICATIONS OF
LI-FI
 TRAFFIC
LIGHTS

22.  INTRINSICALLY
SAFE ENVIRONMENT

23.  Airlines

24.  Street
Lamps as Access Points

25.  In
Radio Frequency Hostile Environments

26. Common Misconceptions










The lights flicker.
You cannot dim the lights.
VLC is uni-directional (downlink or broadcast
only).
There will be interference from sunlight.
Lights need to be on so this is inefficient.
You must have line-of-sight.
This is a disruptive technology.
You need special LEDs
VLC is a complex technology
It will never work!

27. 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 hotspot to
transmit wireless data and we will proceed
toward the cleaner, greener, safer and
brighter future. This may solve issues such as
the shortage of radio frequency bandwidth
and also allow internet where traditional
radio based wireless isn’t allowed such as
aircraft or hospitals. One of the shortcomings
however is that it only work in line of sight.

28. References
 http://purevlc.co.uk/top-10-li-fi-myths/
 http://www.ted.com/talks/harald_haas_w
ireless_data_from_every_light_bulb.html
 http://timesofindia.indiatimes.com/home/s
cience/Now-just-light-a-bulb-to-switch-onyourbroadband/articleshow/9713554.cms
 http://www.independent.co.uk/news/scie
nce/lifi-revolution-internet-connectionsusing-light-bulbs-are-250-times-faster-thanbroadband-8909320.html