1. ACKNOWLEDGEMENT
I thank my seminar guide Mrs. Rahul mathur for his proper guidance, and valuable
suggestions. I am indebted to Mrs. Surendra bohra, the HOD, ECE department & other faculty
members for giving me an opportunity to learn and present the seminar. If not for the above
mentioned people my seminar would never have been completed successfully.
I once again extend my sincere thanks to all of them.
Vikash jakhar
(student of electronics & comm.branch).
1

2. INDEX OF REPORT
Sr.no
Objectives Names
1.
Abstract of Li-Fi technology ……………………………………………….01
2.
Introduction to Li-Fi technology …………………………………………….02
3.
Genesis of LI-FI technology …………………………………………………..05
4.
How Li-Fi Works?
5.
Comprision Between Li-Fi & Wi-Fi ………………………………………..11
6.
How LI-FI Light Sources Work? …………………………………………….13
7.
Function Of The Bulb ?
8.
Application area of li-fi technology… ……………………………………….17
9.
Conclusion
………...…………………………………………………….31
10.
References
…….………………………………………………………..32
……………………………………………………….07
……………………………………………………14
2

3. Abstract of Li-Fi Technology:Whether you‘re using wireless internet in a coffee shop, stealing it from the guy next
door, or competing for bandwidth at a conference, you‘ve probably gotten frustrated at the slow
speeds you face when more than one device is tapped into the network. As more and more
people and their many devices access wireless internet, clogged airwaves are going to make it
increasingly difficult to latch onto a reliable signal. But radio waves are just one part of the
spectrum that can carry our data. What if we could use other waves to surf the internet? One
German physicist,DR. Harald Haas, has come up with a solution he calls ―Data Through
Illumination‖—taking the fiber out of fiber optics by sending data through an LED light bulb
that varies in intensity faster than the human eye can follow. It‘s the same idea behind infrared
remote controls, but far more powerful. Haas says his invention, which he calls D-Light, can
produce data rates faster than 10 megabits per second, which is speedier than your average
broadband connection. He envisions a future where data for laptops, smartphones, and tablets is
transmitted through the light in a room. And security would be a snap—if you can‘t see the light,
you can‘t access the data.
Li-Fi is a VLC, visible light communication, technology developed by a team of
scientists including Dr Gordon Povey, Prof. Harald Haas and Dr Mostafa Afgani at the
University of Edinburgh. The term Li-Fi was coined by Prof. Haas when he amazed people by
streaming high-definition video from a standard LED lamp, at TED Global in July 2011. Li-Fi is
now part of the Visible Light Communications (VLC) PAN IEEE 802.15.7 standard. ―Li-Fi is
typically implemented using white LED light bulbs. These devices are normally used for
illumination by applying a constant current through the LED. However, by fast and subtle
variations of the current, the optical output can be made to vary at extremely high speeds.
3

4. Unseen by the human eye, this variation is used to carry high-speed data,‖ says Dr Povey, ,
Product Manager of the University of Edinburgh's Li-Fi Program ‗D-Light Project‘.
Introduction of Li-Fi Technology:In simple terms, 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.
Since simple light bulbs are used, there can technically be any number of access points.
This technology uses a part of the electromagnetic spectrum that is still not greatly
utilized- The Visible Spectrum. Light is in fact very much part of our lives for millions and
millions of years and does not have any major ill effect. Moreover there is 10,000 times more
space available in this spectrum and just counting on the bulbs in use, it also multiplies to 10,000
times more availability as an infrastructure, globally.
It is possible to encode data in the light by varying the rate at which the LEDs flicker on
and off to give different strings of 1s and 0s. The LED intensity is modulated so rapidly that
human eyes cannot notice, so the output appears constant.
More sophisticated techniques could dramatically increase VLC data rates. Teams at the
University of Oxford and the University of Edinburgh are focusing on parallel data transmission
using arrays of LEDs, where each LED transmits a different data stream. Other groups are using
mixtures of red, green and blue LEDs to alter the light's frequency, with each frequency
encoding a different data channel.
Li-Fi, as it has been dubbed, has already achieved blisteringly high speeds in the lab.
Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over
500 megabytes per second using a standard white-light LED. Haas has set up a spin-off firm to
sell a consumer VLC transmitter that is due for launch next year. It is capable of transmitting
data at 100 MB/s - faster than most UK broadband connections.
4

5. LiFi is transmission of data through illumination by taking the fiber out of fiber optics by
sending data through a LED light bulb that varies in intensity faster than the human eye can
follow.Li-Fi is the term some have used to label the fast and cheap wireless communication
system, which is the optical version of Wi-Fi. The term was first used in this context byHarald
Haas in his TED Global talk on Visible LightCommunication. ―At the heart of this technology is
a new generation of high brightness light-emitting diodes‖, says Harald Haas from the University
of Edinburgh, UK,‖Verysimply, if the LED is on, you transmit a digital 1, if it‘s offyou transmit
a 0,‖Haas says, ―They can be switched on and offvery quickly, which gives nice opportunities
for transmitteddata.‖It is possible to encode data in the light by varying therate at which the
LEDs flicker on and off to give different strings of 1s and 0s.The LED intensity is modulated so
rapidly that human eye cannot notice, so the output appears constant. More sophisticated
techniques could dramatically increase VLC data rate. Terms at the University of Oxford and the
University of Edingburgh are focusing on parallel data transmission using array of LEDs, where
each LED transmits a different data stream. Other group are using mixtures of red,
green and blue LEDs to alter the light frequency encoding a different data channel.Li-Fi, as it has
been dubbed, has already achieved blisteringly high speed in the lab. Researchers at the Heinrich
Hertz Institute in Berlin,Germany,have reached data rates of over 500 megabytes per second
using a standard white-light LED. The technology was demonstrated at the 2012 Consumer
Electronics Show in Las Vegas using a pair of
Casio smart phones to exchange data using light of varying intensity given off from their screens,
detectable at a distance of up to ten metres.
5

6. Fig.1 Li-Fi enviorment
In October 2011 a number of companies and industry groups formed the Li-Fi Consortium, to
promote high-speed optical wireless systems and to overcome the limited amount of
radiobasedwireless spectrum available by exploiting a completely different part of the
electromagnetic spectrum. The consortium believes it is possible to achieve more than 10 Gbps,
theoretically allowing a high-definition film to be downloaded
in 30 seconds.
Li-Fi: A New Paradigm in Wireless Communication
Most of us are familiar with Wi-Fi (Wireless Fidelity), which uses 2.4-5GHz RF to deliver
wireless Internet access around our homes, schools, offices and in public places. We have
become quite dependent upon this nearly ubiquitous service. But like most technologies, it has its
limitations.While Wi-Fi can cover an entire house, its bandwidth is typically limited to 50-100
6

7. megabits per second (Mbps) today using the IEEE802.11n standard. This is a good match to the
speed of most current Internet services, but insufficient for moving large data files like HDTV
movies, music libraries and video games.The more we become dependent upon ‗the cloud‘ or
our own ‗media servers‘ to store all of our files, including movies, music, pictures and games,
the more we will want bandwidth and speed. Therefore RF-based technologies such as today‘s
Wi-Fi are not the optimal way. In addition, Wi-Fi may not be the most efficient way to provide
new desired capabilities such as precision indoor positioning and gesture recognition.Optical
wireless technologies, sometimes called visible light communication (VLC), and more recently
referred to as Li-Fi (Light Fidelity), on the other hand, offer an entirely new paradigm in wireless
technologies in terms of communication speed, flexibility and usability.
Fig. 1: Li-Fi as a superset of different optical wireless technologies involving
communication, positioning, natural user interfaces and many more
Genesis of LI-FI:
Harald Haas, a professor at the University of Edinburgh who began his research in the
field in 2004, gave a debut demonstration of what he called a Li-Fi prototype at the TEDGlobal
7

8. conference in Edinburgh 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
white LED light bulbs (here), thus the idea has been around for awhile and various other global
teams are also exploring the possibilities.
8

9. How Li-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. However,
by fast and subtle variations of the current, the optical output can be made to vary at extremely
high speeds. This very property of optical current is used in Li-Fi setup. 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. Hence all that is required is some LEDs and a controller that code data into
those LEDs. All one has to do is to vary the rate at which the LED‘s flicker depending upon the
data we want to encode. 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.
9

10. To further get a grasp of Li-Fi consider an IR remote.(fig 3.3). It sends a single data
stream of bits at the rate of 10,000-20,000 bps. Now replace the IR LED with a Light Box
containing a large LED array. This system, fig 3.4, is capable of sending thousands of such
streams at very fast rate.
10

11. Light is inherently safe and can be used in places where radio frequency communication
is often deemed problematic, such as in aircraft cabins or hospitals. So visible light
communication not only has the potential to solve the problem of lack of spectrum space, but can
also enable novel application. The visible light spectrum is unused, it's not regulated, and can be
used for communication at very high speeds.
This brilliant idea was first showcased by Harald Haas fromUniversity of Edinburgh, UK,
in his TED Global talk on VLC.He explained,‖ Very simple, if the LED is on, you transmit
adigital 1, if it‘s off you transmit a 0. The LEDs can beswitched on and off very quickly, which
gives nice
opportunities for transmitting data.‖ So what you require at allare some LEDs and a controller
that code data into thoseLEDs. We have to just vary the rate at which the LED‘sflicker
depending upon the data we want to encode. Furtherenhancements can be made in this method,
like using an arrayof LEDs for parallel data transmission, or using mixtures ofred, green and blue
LEDs to alter the light‘s frequency witheach frequency encoding a different data channel.
Suchadvancements promise a theoretical speed of 10 Gbps –meaning you can download a full
high-definition film in just30 seconds. Simply awesome! But blazingly fast data ratesand
11

12. depleting bandwidths worldwide are not the only reasonsthat give this technology an upper hand.
Since Li-Fi uses justthe light, it can be used safely in aircrafts and hospitals that areprone to
interference from radio waves. This can even workunderwater where Wi-Fi fails completely,
thereby throwingopen endless opportunities for military operations
Imagine only needing to hover under a street lamp to getpublic internet access, or
downloading a movie from the lampon your desk. There's a new technology on the block which
could, quite literally as well as metaphorically, 'throw light on'how to meet the ever-increasing
demand for high-speedwireless connectivity. Radio waves are replaced by lightwaves in a new
method of data transmission which is beingcalled Li-Fi.Light-emitting diodes can be switched on
and offfaster than the human eye can detect, causing the light sourceto appear to be on
continuously. A flickering light can beincredibly annoying, but has turned out to have its
upside,being precisely what makes it possible to use light for wirelessdata transmission. Lightemitting diodes (commonly referredto as LEDs and found in traffic and street lights, car
brakelights, remote control units and countless other applications)can be switched on and off
faster than the human eye candetect, causing the light source to appear to be oncontinuously,
even though it is in fact 'flickering'. Thisinvisible on-off activity enables a kind of data
transmissionusing binary codes: switching on an LED is a logical '1',switching it off is a logical
'0'. Information can therefore beencoded in the light by varying the rate at which the LEDsflicker
on and off to give different strings of 1s and 0s. Thismethod of using rapid pulses of light to
transmit informationwirelessly is technically referred to as Visible LightCommunication (VLC),
though it‘s potential to compete withconventional Wi-Fi has inspired the popular
characterization Li-Fi.
Visible light communication (VLC)-“A potential solutionto the global
wireless spectrum shortage”
12

13. LiFi (Light Fidelity) is a fast and cheap optical version of Wi-Fi, the technology of which
is based on Visible LightCommunication (VLC).VLC is a data communication medium, which
uses visible light between 400 THz (780 nm)and 800 THz (375 nm) as optical carrier for data
transmissionand illumination. It uses fast pulses of light to transmitinformation wirelessly. The
main components of thiscommunication system are 1) a high brightness white LED,Which acts
as a communication source and 2) a siliconphotodiode which shows good response to visible
wavelengthregion serving as the receiving element? LED can be switchedon and off to generate
digital strings of 1s and 0s. Data can beencoded in the light to generate a new data stream by
varyingthe flickering rate of the LED. To be clearer, by modulatingthe LED light with the data
signal, the LED illumination canbe used as a communication source. As the flickering rate is so
fast, the LED output appears constant to the human eye. Adata rate of greater than 100 Mbps is
possible by using highspeed LEDs with appropriate multiplexing techniques. VLC. data rate can
be increased by parallel data transmission usingLED arrays where each LED transmits a
different data stream.There are reasons to prefer LED as the light source in VLCwhile a lot of
other illumination devices like fluorescent lamp,incandescent bulb etc. are available.
COMPARISION BETWEEN Li-Fi & Wi-Fi
LI-FI is a term of one used to describe visible lightcommunication technology applied to
high speed wirelesscommunication. It acquired this name due to the similarity toWI-FI, only
using light instead of radio.WI-FI is great forgeneral wireless coverage within buildings, and li-fi
is idealfor high density wireless data coverage in confined area andfor relieving radio
interference issues, so the two technologiescan be considered complimentary.
13

14. Table 1.Comparison between current and future wirelesstechnology
The table also contains the current wireless technologies thatcan be used for transferring
data between devices today, i.e.Wi-Fi, Bluetooth and IrDA. Only Wi-Fi currently offers veryhigh
data rates. The IEEE 802.11.n in most implementationsprovides up to 150Mbit/s (in theory the
standard can go to600Mbit/s) although in practice you receive considerably lessthan this. Note
that one out of three of these is an opticaltechnology.
14

15. Li-Fi technology is based on LEDs for the transfer of data.The transfer of the data can be
with the help of all kinds oflight, no matter the part of the spectrum that they belong. Thatis, the
light can belong to the invisible, ultraviolet or thevisible part of the spectrum. Also, the speed of
the internet isincredibly high and you can download movies, games, musicetc in just a few
minutes with the help of this technology.Also, the technology removes limitations that have been
puton the user by the Wi-Fi. You no more need to be in a regionthat is Wi-Fi enabled to have
access to the internet. You cansimply stand under any form of light and surf the internet asthe
connection is made in case of any light presence. Therecannot be anything better than this
technology.
Technology Brief:How LI-FI Light Sources Work:LI-FI is a new class of high intensity light source of solid state design bringing clean lighting
solutions to general and specialty lighting. With energy efficiency, long useful lifetime, full
spectrum and dimming, LI-FI lighting applications work better compared to conventional
approaches. This technology brief describes the general construction of LI-FI lighting systems
and the basic technology building blocks behind their function.
The LIFI™ product consists of 4 primary sub-assemblies:
• Bulb
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure
The PCB controls the electrical inputs and outputs of the lamp and houses the microcontroller
used to manage different lamp functions.
15

16. 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 plasma generates an intense
source of light.
All of these subassemblies are contained in an aluminum enclosure
FUNCTION OF THE BULB:At the heart of LIFI™ is the bulb sub-assembly where a sealed bulb is embedded in a dielectric
material. This design is more reliable than conventional light sources that insert degradable
electrodes into the bulb. The dielectric material serves two purposes; first as a waveguide for the
RF energy transmitted by the PA and second as an electric field concentrator that focuses energy
in the bulb. The energy from the electric field rapidly heats the material in the bulb to a plasma
state that emits light of high intensity and full spectrum.
The design and construction of the LIFI™ light source enable efficiency, long stable life, full
spectrum intensity that is digitally controlled and easy to use.
16

17. 17

18. Fig :- representing the data transfer using light
18

19. Application area of li-fi technology
 Airways:-
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 radioways ,li-fi is introduce.
 Green information technology:Green information technology means that unlike radiowaves and other
communication waves affects on the birds , human bodys etc. Li-Fi never gives such
side effects on any living thing..
Free From Frequency Bandwidth Problem:Li-fi is an communication media in the form of light ,so no matter about
the frequency bandwidth problem . It does not require the any bandwidth
spectrum i.e. we don‘t need to pay any amount for communication and licence.
 Increase Communication Safety:Due to visual light communication , the node or any terminal attach to our
network is visible to the host of network .
 Multi User Communication:Li-Fi supports the broadcasting of network , it helps to share multiple
thing at a single instance called broadcasting.
 Lightings Points Used as Hotspot:-
19

20. Any lightings device is performed as a hotspot it means that the light
device like car lights, ceiling lights , street lamps etc area able to spread internet
connectivity using visual light communication. Which helps us to low cost
architecture for hotspot.
Hotspot is an limited region in which some amount of device can
access the internet connectivity .
4.1 You Might Just Live Longer
For a long time, medical technology has lagged behind the restof the wireless world.
Operating rooms do not allow Wi-Fiover radiation concerns, and there is also that whole lack
ofdedicated spectrum. While Wi-Fi is in place in many hospitals,interference from cell phones
and computers can block signalsfrom monitoring equipment. Li-Fi solves both problems: lights
are not only allowed in operating rooms, but tend to be themost glaring (pun intended) fixtures in
the room. And, as Haasmentions in his TED Talk, Li-Fi has 10,000 times thespectrum of Wi-Fi,
so maybe we can, I dunno, delegate redlight to priority medical data. Code Red!
4.2 Airlines
Airline Wi-Fi. Ugh. Nothing says captive audience like havingto pay for the "service" of
dial-up speed Wi-Fi on the plane.And don‘t get me started on the pricing. The best I‘ve heard
sofar is that passengers will "soon" be offered a "high-speedlike" connection on some airlines.
United is planning onspeeds as high as 9.8 Mbps per plane. Uh, I have twice thatcapacity in my
living room. And at the same price as checkinga bag, I expect it. Li-Fi could easily introduce that
sort ofspeed to each seat's reading light. I‘ll be the guy WoWing nextto you. Its better than
listening to you tell me about yourwildly successful son, ma‘am.
4.3 Smarter Power Plants
20

21. Wi-Fi and many other radiation types are bad for sensitiveareas. Like those surrounding
power plants. But power plantsneed fast, inter-connected data systems to monitor things like
demand, grid integrity and (in nuclear plants) coretemperature. The savings from proper
monitoring at a singlepower plant can add up to hundreds of thousands of dollars.Li-Fi could
offer safe, abundant connectivity for all areas ofthese sensitive locations. Not only would this
save moneyrelated to currently implemented solutions, but the draw on apower plant‘s own
reserves could be lessened if they haven‘tyet converted to LED lighting
4.4 Undersea Awesomeness
Underwater ROVs, those favourite toys of treasure seekersand James Cameron, operate
from large cables that supplytheir power and allow them to receive signals from their
pilotsabove. ROVs work great, except when the tether isn‘t longenough to explore an area, or
when it gets stuck on something.If their wires were cut and replaced with light — say from
asubmerged, high-powered lamp — then they would be muchfreer to explore. They could also
use their headlamps tocommunicate with each other, processing data autonomouslyand referring
findings periodically back to the surface, all thewhile obtaining their next batch of orders.
4.5. It Could Keep You Informed and Save Lives
Say there‘s an earthquake in New York. Or a hurricane. Takeyour pick — it‘s a wacky
city. The average New Yorker maynot know what the protocols are for those kinds of
disasters.Until they pass under a street light, that is. Remember, withLi-Fi, if there‘s light, you‘re
online. Subway stations andtunnels, common dead zones for most emergencycommunications,
pose no obstruction. Plus, in times lessstressing cities could opt to provide cheap high-speed
Webaccess to every street corner.
21

22. USES IN VARIOUS AREAS
Can be used in the places where it is difficult to lay the opticalfiber like hospitals. In
operation theatre LiFi can be used formodern medical instruments. In traffic signals LiFi can
beused which will communicate with the LED lights of the carsand accident numbers can be
decreased. Thousand andmillions of street lamps can be transferred to LiFi lamps totransfer data.
In aircraft LiFi can be used for datatransmission.
It can be used in petroleum or chemical plants whereother transmission or frequencies
could be hazardous.
Li-Fi revolution: internet connections using light bulbs are 250 times faster than broadbandLi-Fi,
an alternative to Wi-Fi that transmits data using the spectrum of visible light, has achieved a new
breakthrough, with UK scientists reporting transmission speeds of 10Gbit/s – more than 250
times faster than ‗superfast‘ broadband.
The fastest speed previously reported was 3Gbit/s, achieved earlier this year by the Fraunhofer
Heinrich Hertz Institute in Germany. Chinese researchers also claimed this month to have
produced a 150Mbp/s connection, but some experts were doubtful without seeing further proof.
The term Li-Fi was coined by Edinburgh University's Prof Harald Haas during a TED talk in
2011 (see below for video) though the technology is also known as visible light communications
(VLC).
Many experts claim that Li-Fi represents the future of mobile internet thanks to its reduced costs
and greater efficiency compared to traditional Wi-Fi.
Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi
utilises radio waves, Li-Fi uses visible light. This is a distinct advantage in that the visible light is
far more plentiful than the radio spectrum (10,000 times more in fact) and can achieve far greater
data density.
22

23. Li-Fi signals work by switching bulbs on and off incredibly quickly – too quickly to be noticed
by the human eye. This most recent breakthrough builds upon this by using tiny micro-LED
bulbs to stream several lines of data in parallel.
The research was carried out by the Ultra Parallel Visible Light Communications project, a joint
venture between the universities of Oxford, Cambridge, Edinburgh, St Andrews and Strathclyde,
and funded by the Engineering and Physical Sciences Research Council.
Existing LED light bulbs could be converted to transmit Li-Fi signals with a single microchip,
and the technology would also be of use in situations where radio frequencies cannot be used for
fear of interfering with electronic circuitry.
And although Li-Fi bulbs would have to be kept on to transmit data, the bulbs could be dimmed
to the point that they were not visible to humans and yet still functional. One draw-back is that
the data receiver would have to be in sight of the transmitter-bulb as visible light does not
penetrate solid materials.
The makers of Li-Fi note that this quality might actually be an advantage in some scenarios,
making Li-Fi more secure than Wi-Fi with hackers unable to access unsecured internet
connections from out of sight of the transmitter.
Li-Fi, an alternative to Wi-Fi that transmits data using the spectrum of visible light, has achieved
a new breakthrough, with UK scientists reporting transmission speeds of 10Gbit/s – more than
250 times faster than ‗superfast‘ broadband.
The fastest speed previously reported was 3Gbit/s, achieved earlier this year by the Fraunhofer
Heinrich Hertz Institute in Germany. Chinese researchers also claimed this month to have
produced a 150Mbp/s connection, but some experts were doubtful without seeing further proof.
The term Li-Fi was coined by Edinburgh University's Prof Harald Haas during a TED talk in
2011 (see below for video) though the technology is also known as visible light communications
(VLC).
23

24. Many experts claim that Li-Fi represents the future of mobile internet thanks to its reduced costs
and greater efficiency compared to traditional Wi-Fi.
Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi
utilises radio waves, Li-Fi uses visible light. This is a distinct advantage in that the visible light is
far more plentiful than the radio spectrum (10,000 times more in fact) and can achieve far greater
data density.
Li-Fi signals work by switching bulbs on and off incredibly quickly – too quickly to be noticed
by the human eye. This most recent breakthrough builds upon this by using tiny micro-LED
bulbs to stream several lines of data in parallel.
The research was carried out by the Ultra Parallel Visible Light Communications project, a joint
venture between the universities of Oxford, Cambridge, Edinburgh, St Andrews and Strathclyde,
and funded by the Engineering and Physical Sciences Research Council.
Existing LED light bulbs could be converted to transmit Li-Fi signals with a single microchip,
and the technology would also be of use in situations where radio frequencies cannot be used for
fear of interfering with electronic circuitry.
And although Li-Fi bulbs would have to be kept on to transmit data, the bulbs could be dimmed
to the point that they were not visible to humans and yet still functional. One draw-back is that
the data receiver would have to be in sight of the transmitter-bulb as visible light does not
penetrate solid materials.
The makers of Li-Fi note that this quality might actually be an advantage in some scenarios,
making Li-Fi more secure than Wi-Fi with hackers unable to access unsecured internet
connections from out of sight of the transmitter.
Visible light communications
Many people‘s first exposure to optical wireless technology was VLC. This emerging technology
offers optical wireless communications by using visible light. Today, it is seen as an alternative
to different RF-based communication services in wireless personal-area networks. An additional
24

25. opportunity is arising by using current state-of-the-art LED lighting solutions for illumination
and communication at the same time and with the same module. This can be done due to the
ability to modulate LEDs at speeds far faster than the human eye can detect while still providing
artificial lighting.Thus while LEDs will be used for illumination, their secondary duty could be
to ‗piggyback‘ data communication onto lighting systems. This will be particularly relevant in
indoor ‗smart‘ lighting systems, where the light is always ‗on.‘Other examples for outdoor use
include intelligent traffic systems to exchange data between vehicles, and between vehicles and
road infrastructure like traffic lights and control units. Alternatively, the LEDs‘ primary purpose
could be to transmit information while the secondary purpose of illumination would be to alert
the user to where the data is being transmitted from.In contrast to infrared, the so-called ―what
you see is what you send‖ feature can be used to improve the usability of transmitting data at
shorter point-to-point distances between different portable or fixed devices. There, illumination
can be used for beam guiding, discovery or generating an alarm for misalignment.The premise
behind VLC is that because lighting is nearly everywhere, communications can ride along for
nearly free. Think of a TV remote in every LED light bulb and you‘ll soon realise the
possibilities of this technology.
(A) GigaDock
(B) GigaBeam
25

26. (c) GigaShower
(D) GigaMIMO
Fig. 2: GigaSpeed usage models (Images courtesy: TriLumina Corp.)
One of the biggest attractions of VLC is the energy saving of LED technology. Nineteen per cent
of the worldwide electricity is used for lighting. Thirty billion light bulbs are in use worldwide.
Assuming that all the light bulbs are exchanged with LEDs, one billion barrels of oil could be
saved every year, which again translates into energy production of 250 nuclear power
plants.Driven by the progress of LED technology, visible light communication is gaining
attention in research and development. The VLC Consortium (VLCC) in Japan was one of the
first to introduce this technology.After establishing a VLC interest group within the IEEE 802.15
wireless personal-area networks working group, the IEEE 802.15.7 task group was established
by the industry, research institutes and universities in 2008. The final standard was approved in
2011. It specifies VLC comprising mobile-to-mobile (M2M), fixed-to-mobile (F2M) and
infrastructure-to-mobile (I2M) communications. There, the focus is on low-speed, medium-range
communications for intelligent traffic systems and on high-speed, short-range M2M and F2M
communications to exchange, for example, multimedia data. Data rates are supported from some
100 kbps up to 100 Mbps using different modulation schemes.Other standardisation groups are
working on standardised optical wireless communication (OWC) solutions using visible and
infrared light. The most important groups are IrDA with its new 10 Giga-IR working group, ISO
and ICSA.Li-Fi—the superset of VLC & Co.VLC represents only a fraction of what appears
to be a much larger movement towards optical wireless technologies in general. This larger
world has been dubbed ‗Li-Fi‘ (Light Fidelity) by people such as Dr Harald Haas of Edinburgh
University and organisations such as the Li-Fi Consortium.In that connection, Li-Fi comprises
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27. several optical wireless technologies such as optical wireless communication, navigation and
gesture recognition applied for natural user interfaces (Fig. 1). Thus it provides a completely new
set of optical technologies and techniques to offer users add-on as well as complementary
functionalities compared to well-known and established RF services. This could reach from a
new user experience regarding communication speeds in the gigabit-class to bridge the wellknown spec-trum crunch, over to precise indoor positioning or controlling video games,
machines or robots with entirely new natural user interfaces. Finally, these and many more could
be merged to a full-featured Li-Fi cloud providing wireless services for other future applications
as well.What Li-Fi stands forLi-Fi comprises a wide range of frequencies and wavelengths,
from the infrared through visible and down to the ultraviolet spectrum. It includes sub-gigabit
and gigabit-class com-munication speeds for short, medium and long ranges, and unidirectional
and bidirectional data transfer using line-of-sight or diffuse links, reflec-tions and much more. It
is not limited to LED or laser technologies or to a particular receiving technique. Li-Fi is a
framework for all of these providing new capabilities to current and future services, applications
and end users.Usage modelsWithin a local Li-Fi cloud several databased services are supported
through a heterogeneous communication sys-tem. In an initial approach, the Li-Fi Consortium
defined different types of technologies to provide secure, reliable and ultra-high-speed wireless
communication interfaces. These technologies included giga-speed technologies, optical mobility
technologies, and navigation, precision location and gesture recognition technologies.For gigaspeed technologies, the Li-Fi Consortium defined GigaDock, GigaBeam, GigaShower, GigaSpot
and GigaMIMO models (Fig. 2) to address different user scenarios for wireless indoor and
indoor-like data transfers. While GigaDock is a wireless docking solution including wireless
charging for smartphones tablets or notebooks, with speeds up to 10 Gbps, the GigaBeam model
is a point-to-point data link for kiosk applications or portable-to-portable data exchanges. Thus a
two-hour full HDTV movie (5 GB) can be transferred from one device to another within four
seconds.GigaShower, GigaSpot and Giga-MIMO are the other models for in-house
communication. There a transmitter or receiver is mounted into the ceiling connected to, for
example, a media server. On the other side are portable or fixed devices on a desk in an office, in
an operating room, in a production hall or at an airport. GigaShower provides unidirectional data
services via several channels to multiple users with gigabit-class com-munication speed over
several metres. This is like watching TV channels or listening to different radio stations where no
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28. uplink channel is needed. In case GigaShower is used to sell books, music or movies, the
connected media server can be accessed via Wi-Fi to process payment via a mobile device.
GigaSpot and GigaMIMO are optical wireless single- and multi-channel HotSpot solutions
offering bidirectional gigabit-class communication in a room, hall or shopping mall for
example.How Li-Fi worksImagine yourself walking into a mall where GPS signals are
unavailable but the mall is equipped with ceiling bulbs that create their own ‗constellation‘ of
navigation beacons. As the camera of your cellphone automatically receives these signals, it
switches your navigation software to use this information to guide you to the ATM machine
you‘re looking for.You conclude your ATM transaction and notice the GigaSpot sign for instant
digital movie downloads. You pick out that new Tom Cruise movie using your phone‘s payment
facility, and then download within a few seconds the high-definition movie into the GigaLink
flash drive plugged into the USB port of your smartphone.As you walk away, your phone
notifies you that the leather jacket Tom featured in the movie is on sale nearby. You walk over
towards the show window and your image comes up on the screen, wearing that coveted jacket.
You turn and pose while the image matches your orientation and body gestures for a ‗digital
fitting.‘ When you walk into the store, the clerk hands you the actual jacket in exactly your
size.On the verge of a breakthroughFirst applications of Li-Fi have been put to use already, for
example, in hospitals where RF signals are a threat due to interference problems with medical
equipment such as blood pumps and other life supporting instruments. Axiomtek Europe
presented such a product at the Embedded World exhibition in Nürn-berg, Germany. The
prototype of a mobile phone with an incorporated VLC system was presented by Casio at the
Consumer Electronics Show in Las Vegas in January this year. In the coming years, we will see
more Li-Fi products entering the market, both in the industrial as well as consumer markets.
Imagine only needing to hover under a street lamp to get public internet access, or downloading
a movie from the lamp on your desk. There's a new technology on the block which could, quite
literally as well as metaphorically, 'throw light on' how to meet the ever-increasing demand for
high-speed wireless connectivity. Radio waves are replaced by light waves in a new method of
data transmission which is being called Li-Fi.
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29. light-emitting diodes can be switched on and off faster than the human eye can detect, causing
the light source to appear to be on continuously
A flickering light can be incredibly annoying, but has turned out to have its upside, being
precisely what makes it possible to use light for wireless data transmission. Light-emitting diodes
(commonly referred to as LEDs and found in traffic and street lights, car brake lights, remote
control units and countless other applications) can be switched on and off faster than the human
eye can detect, causing the light source to appear to be on continuously, even though it is in fact
'flickering'. This invisible on-off activity enables a kind of data transmission using binary codes:
switching on an LED is a logical '1', switching it off is a logical '0'. Information can therefore be
encoded in the light by varying the rate at which the LEDs flicker on and off to give different
strings of 1s and 0s. This method of using rapid pulses of light to transmit information wirelessly
is technically referred to as Visible Light Communication (VLC), though its potential to compete
with conventional WiFi has inspired the popular characterisation Li-Fi.
The concept of Li-Fi is currently attracting a great deal of interest, not least because it may offer
a genuine and very efficient alternative to radio-based wireless. As a growing number of people
and their many devices access wireless internet, the airwaves are becoming increasingly clogged,
making it more and more difficult to get a reliable, high-speed signal. The opportunity to exploit
a completely different part of the electromagnetic spectrum is therefore very appealing. As well
as being a potential solution to our ever-increasing hunger for bandwidth, Li-Fi has other
advantages over WiFi, such as being safe to use on an aircraft, in hospitals and medical devices,
and even underwater, where WiFi doesn't work at all.
Research suggests that Li-Fi has the potential to be faster, safer and cheaper than
conventional WiFi technology. In more ways than one, it looks like the future of wireless
communication definitely has a 'bright side'.
Background – Li-Fi
The technology underpinning Li-Fi was pioneered by German physicist Harald Haas, currently
based at the University of Edinburgh in the UK. Haas coined the term Li-Fi in 2011 in the
context of a talk presenting the new technology at the TED (Technology Entertainment and
Design) Global conference. The word quickly entered common parlance as an instantly
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30. recognisable alternative to WiFi. Both terms are examples of abbreviations linguists sometimes
describe as clipped forms, i.e. WiFi = wireless fidelity, Li-Fi = light fidelity.
Haas's research project, originally known as D-Light (short for Data Light), is now set to launch
a prototype Li-Fi application under the name of newly-formed company VLC (Visible Light
Communication) Ltd, which was set up to commercialize the technology.
Would you like to use this BuzzWord article in class? Visit onestopenglish.com for tips and
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with light and abbreviations.
We use it in our everyday life, private life, business life as currently 2G, 3G, 4G uses radio
waves. Wireless communication has become an utility like also have 5 billion of mobile phones
electricity and water .Mobile phones transmit 600TB of data every month.We have 1.4 million
cellular base stations deployed .
The LiFi product consists of 4 primary sub-assemblies: 1.Bulb 2.RF Power Amplifier Circuit
(PA) 3.Printed Circuit Board (PCB) 4.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.
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 this digital data in the form of light. On the other end this light
is detected by photo sensitive devices. Next this light is amplified and processed and then fed to
the device.
You Can Use Li-Fi In Hospitals And Aircrafts Also. Cheaper Then WiFi , Since Visible Light
Spectrum Is A Free Spectrum Band. No License Needed. Thousands And Millions Of Street
Lamps Can Be Converted To Li-fi Spots. Light Is Readily Available In Every Part Of The
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31. World. This Makes It Easy For People In Airplanes To Work On The Internet. There Are An
Estimated 14 Billion Light Sources On Earth And Each Can Be Easily Converted Into A Li-Fi
Hotspot.
Advantages of LiFi
High efficient.Led light consumes less energy. Data through illumination and thus data
transmission comes for free. We have the infrastructure available and already installed.
Efficiency Light box are already present. 10000times more spectrum than Radio waves.
Advantages of Li-Fi Other Advantages of Li-Fi Technology Capacity
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. Visible light
cannot penetrate through solid objects There should be line of sight between sender and receiver
Limitations of LiFi
To prove that the light bulb was the source of data stream, he periodically blocked the beam of
light, causing the connection to drop. Dr. Harald Hass demonstrated his invention using an
ordinary table lamp that successfully transmitted data at speeds exceeding 10Mbps . Yes, this is
already proven.
LiFi is Proven or Not ? Is it a proven technology?
Demonstration by Harald Hass at TED talk, 2013
Video Demonstration of LiFi Li-Fi
It can used in petroleum or chemical plants
where other transmission or frequencies could be hazardous. In aircraft Li-Fi can be used to
transmit data.
Thousands and millions of street lamps can be transferred to Li-Fi lamps to transfer data.
In traffic signals Li-Fi can be used which will communicate with the LED lights of the cars and
accident numbers can be decreased. Can be used in the places where it is difficult to lay the
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32. optical fiber like hospitals. In operation theatre Li-Fi can be used for modern medical
instruments.
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 Wi-Fi hotspot to transmit wireless
data and we will proceed onwards the Cleaner, Greener, Safer and Brighter future.
32

33. CONCLUSION
The possibilities are numerous and can be explored further. If his 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. The concept of
Li-Fi is currently attracting a great deal of interest, not least because it may offer a genuine and
very efficient alternative to radio-based wireless. As a growing number of people and their many
devices access wireless internet, the airwaves are becoming increasingly clogged, making it more
and more difficult to get a reliable, high-speed signal. 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
direct line of sight.
33

34. Refferences:1:- http://timesofindia.indiatimes.com/home/science/Now-just-light-a-bulb-to-switch-on-yourbroadband/articleshow/9713554.cms
2:- http://oledcomm.com/lifi.html
3:- http://en.wikipedia.org/wiki/Li-Fi
4:-http://slideshare.com/li-fitech.html
[1] seminarprojects.com/s/seminar-report-on-lifi
[2] http://en.wikipedia.org/wiki/Li-Fi
[3] http://teleinfobd.blogspot.in/2012/01/what-is-lifi.html
[4] technopits.blogspot.comtechnology.cgap.org/2012/01/11/a-lifi-world/
[5] www.lificonsortium.org/
[6] the-gadgeteer.com/2011/08/29/li-fi-internet-at-thespeed-of-light/
[7] en.wikipedia.org/wiki/Li-Fi
[8] www.macmillandictionary.com/buzzword/entries/Li-Fi.html
[9] dvice.com/archives/2012/08/lifi-ten-ways-i.php
[10] 8. Will Li-Fi be the new Wi-Fi?, New Scientist, byJamie Condliffe, dated 28 July 2011
[11] http://www.digplanet.com/wiki/Li-Fi
[12] 10.‖Visible-light communication: Tripping the lightfantastic: A fast and cheap optical
version of Wi-Fi iscoming‖, Economist, dated 28Jan 2012
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