Li-Fi is a technology that uses light from LED bulbs to transmit data wirelessly. It works by switching the state of LED bulbs on and off very rapidly in order to transmit digital signals. The fast switching is undetectable to the human eye but allows for high-speed data transmission. Li-Fi has several advantages over traditional Wi-Fi including very high speeds of over 1 Gbps, no interference from radio frequencies, improved security, and energy efficiency. While Li-Fi has promise, it also faces challenges in only working within line of sight of the light source and potentially higher costs than Wi-Fi systems. Researchers continue developing the technology to increase speeds and implementation.

1. Under the guidance of
Asst. prof GIRISH KUMAR D
Presented by
KOTESHWAR RAO M
(3BR11IS017)

2.  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- LIGHT FIDEALITY

3.  Li-Fi is now part of visible light communication (VLC).
 It can be very easily explained as, if the LED is ON, you
are transmitting the data means you transmit a digital 1 ;
and if the LED is OFF you transmit a digital 0,or null, or
simply no data transfer happens.
 As one can switch them on and off very frequently one
can transmit data easily because the LEDs intensity is
modulated so rapidly that human eye cannot notice, so the
output in form of light appears constant and hence
offering permanent connectivity.

4.  Till now it was implemented through white LED bulbs only but
teams at the University of Oxford and the University of
Edinburgh are focusing on parallel data transmission by using
multiple LEDs or array of LEDs, where each LED transmits a
different stream of data.
 Mixtures of red, blue, green LEDs are also used by some
groups to encode different data channels by altering the light
frequencies.
 In simple terms we can consider it to be a light based Wi-Fi
which has achieved blistering high speed in the labs at Heinrich
Hertz institute in Berlin, Germany of around 500 megabytes
per second using a standard white-light LED.
 So quiet obviously, modems would be replaced by transceiver
fitted LED lamps which can serve both in purposes of
lightening the room as well as transmitting the data.

5. Professor Harald Haas,
from the University of
Edinburgh in the UK, is
widely recognised as the
original founder of Li-Fi. He
coined the term Li-Fi and is
Chair of Mobile
Communications at the
University of Edinburgh and
co-founder of pureLiFi.

6.  In October 2011, companies and industry groups formed the
Li-Fi Consortium, to promote high-speed optical wireless
systems and to overcome the limited amount of radio-based
wireless spectrum available by exploiting a completely
different part of the electromagnetic spectrum.A number of
companies offer uni-directional VLC products which is not the
same as Li-Fi.
 VLC technology was exhibited in 2012 using Li-Fi. By August
2013, data rates of over 1.6 Gbit/s were demonstrated over a
single color LED.In September 2013, a press release said that
Li-Fi, or VLC systems in general, do not require line-of-sight
conditions. In October 2013, it was reported Chinese
manufacturers were working on Li-Fi development kits
 In April 2014, the Russian company Stins Coman announced
the development of a Li-Fi wireless local network called
BeamCaster. Their current module transfers data at 1.25
gigabytes per second but foresee boosting speeds up to 5
GB/second in the near future.

8. 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.
1.4 Million 5 Billion

12. 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 bse
used with low power.
HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

15. 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

18. LI FI CONSTRUCTION-
The LI FI product consists of 4 primary sub-assemblies:
• Bulb
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure
3-The PCB controls the electrical inputs and outputs of the lamp and houses
the microcontroller used to manage different lamp functions.
2- An RF (radio-frequency) signal is generated by the solid-state PA and is
guided into an electric field about the bulb.
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
pasma generates an intense source of light. All of these subassemblies are
contained in an aluminum enclosure.

20. Characteristics WI-FI LI-FI
Frequency 2.4GHz to 5GHz No frequency for light
Standard IEEE 802.11 IEEE 802.15
Range 100m Base on LED light
Primary application Wireless local area
networking
Wireless local area
networking
Data transfer rate 11Mbps >1Gbps
Power consumption Medium Low
Cost Medium High
Security Its medium secure Its high secure
Primary devices Notebook computers, Mobile phones, office and

22. Advantages of Li-Fi Technologies
Long service life (10-15 years while usual bulbs last 1-2
years)
Energy Saving (8W LED bulb=60W ordinary Bulb)
Light emitting Diodes are a source of light (release large
amount of energy in the form of light)
Can be switched on/off at very high speed
Energy Efficiency
High speed data transfer
It’s main advantage is it’s bandwidth, It is 10,000 times
than the radio waves
Cost Benefits

23.  The main drawback in LI-FI is power consumption.
 Light signals not easily move just like as radio
signals they will follow certain path so it is also
draw back of LI-FI.
 It consume more power rather that WI-FI
technology.

24. 1. Health Technologies
2. Airlines
3. Power plants
4. Under sea working
5. Information delegation
6. Various other areas
7. Free from frequency bandwidth problem
8. Learning
9. Green Information technology
10. GPS usage
11. Increase Communication safety
12. Multi User Communication
13. Lightings points used as Hotspot

25.  Possibilities for future utilization are abundant. Every light
bulb can be converted into li-fi signal receptor to transfer
data and we could proceed toward the cleaner, safer,
greener and brighter future.
 As we know that the airways are getting clogged day by
day Li-fi can offer a genuine and very efficient alternative.
Li-Fi is enabled by advanced digital transmission
technologies. Optical cell networks based on Li-Fi are the
link between future energy efficient illumination and
cellular communications.
 They can also harness unregulated, unused and vast
amount of electromagnetic spectrum and can even enable
ever smaller cells without the need for new infrastructure.
 The issues of shortage of radio frequency can be tackled
easily with only limitation being that it works in direct line
of sight of light. There are no dead ends to technology and
science. Now both light and radio waves can be used
simultaneously to transfer data and signals

26.  Further enhancements can be ma in this
method, like using an array of LEDs for
parallel data transmission or using mixture
of red, green and blue LEDs to alter the
light’s frequency with each frequency
encoding a different data channels.
 Such advancements promise a theoretical
speed of 10 Gbps-meaning one can download
a full high definition film in just 30 seconds.

27.  M. Afgani, H. Haas, H. Elgala, and D. Knipp,
“Visible Light Communication using OFDM” in
Proc. of the 2nd International Conference on
Testbeds and Research Infrastructures for the
Development of Networks and Communities
(TRIDENTCOM), Barcelona, Spain, March 1-3
2006, pp. 129-134.
 http://www.electronicsforu.com/electronicsforu
/circuitarchives/view_articl
asp?sno=778&title%20=%20Li-
Fi%3A+A+New+Paradigm+in+Wireless+Communica
tion&b_type=new&I =12042
 http://en.wikipedia.org/wiki/Li-Fi

28. THANK YOU