Seminar Report

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Acknowledgement
I thank my seminar guide Dr. Sambit Kumar Mishra H.O.D of
Computer Science Department, GIET, for his proper guidance, and
valuable suggestions. I am indebted to other faculty members of
Computer Science Department 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.
Anjeet Kumar
1301326440
CSE 6th
Sem

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Contents
Sl. No. Content Page No.
1. Introduction 6 - 7
2. Review Of Literature 8
3. Principles Of Li-Fi 9-10
4. Construction Of Li-Fi 11
5. Comparison with Other Technologies 12
6. Applications 13
7. Future Prospectus 14-15
8. Advantages 16
9. Limitations 17
10. Conclusions 18
11. Reference 19

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Abstract
Whether we are using wireless internet in a shopping mall, in college campus or
borrowing it from the friend, or competing for bandwidth at a conference, we
usually get frustrated at the slow speeds we 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. 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’.

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Introduction
Li-fi basically known as “LIGHT FEDILITY” is an outcome of twenty first
century. The basic ideology behind this technology is that the data can be
transmitted through LED light whose intensity varies even faster
than the human eye.
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.
As the transmission of the data takes place through the light emitting diodes
(LED’s) the amount is comparatively small .In modern times, it is called as the
optimized version of WI-FI .The advantageous thing is the wireless
communication which decreases the cost enormously. HARALD HASS, says
that the heart of this technology lies in the intensity and the potential of the light
emitting diodes. The major reason which lead the modern man through this
invention is that the confinement of Wi-Fi to comparatively small distance. As
there are more and more devices coming up day-by-day the signals are
being clogged up due to heavy traffic, there arised a need for an error free
transmission technology. And the solution to this problem was the Li-fi
technology.. It has been designed in such a way that it overcomes the
disadvantages that occurs during the usage of wi-fi. In general terms, Li- fi
works even under water thereby causing a great benefit to the military
operations.
The phycists envisions that this technology would make a great difference
between the assumption and the proof in this case .The demonstration took
place using two Casio smart phones. The data was made to exchange between

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the phones using light. Even though the distance was nominal, it is sure that
there would be a rapid increase in the distance of transmission.AS there is a
limited amount of Radio based wireless spectrum available, a number of
companies formed a consortium called Li-fi consortium in order to promote
high speed optical wireless systems .The members of this consortium believes
that a speed of 10 Gbps can be achieved in no time. If this would be possible
then a high clarity image would take about 30 seconds to download.

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Review Of Literature
In July 2011, Dr. Herald Hass, Professor, mobile communication, University of
Edinburgh, demonstrated Light fidelity for the first time, a method of Visible
light communication (VLC) technology. Li-Fi technology change the scenario
of accessing the internet, stream video, receive emails and much more. This is
come in familiar forms such as infrared, ultraviolet and visible light.
Research into this VLC has been conducted in 2003,mainly in UK, US,
Germany, Korea and Japan. Experiments have shown that VLC is faster, safer
and cheaper than other forms of wireless internet and also eliminates the need
of costly mobile phone radio masts.
In 2007, Hass’s assistant, Mostafa Afgani, first sent data using light signals in
his small lab with equipment including table lamp and its box of electronics.
Hass’s invention centres on modulation of the information embedded from the
LED’s is transmitted by means of many subtle changes made to the intensity of
the light at the ultra high rate of 100 millions cycles per second(100MHZ).The
photo detector in the Hass box converts this tiny variations into a digital signal
from which the transmitted information is extracted.Using a standard white-
light LED, researchers at the Heinrich Hertz Institute in Berlin, Germany,
have reached data rates of over 500 megabytes per second.
Li-Fi Consortium was formed in October 2011 by a group of companies and
industry groups to promote high-speed optical wireless systems and overcome
the limited amount of radio based wireless spectrum. According to the Li-Fi
Consortium, it is possible to achieve more than 10 Gbps of speed, theoretically
which would allow a high-definition film to be downloaded in just 30 seconds.

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Principle Of Li-Fi Technology
The basic idea behind this communication scheme is transmission of ‘Data
through illumination’ . Heart of Li-Fi technology is high brightness LED’s.
The on-off activity of LEDs enables a kind of data transmission using binary
codes mode however the human eye cannot perceive this change and the LEDs
appear to have a constant intensity. Switching on an LED is a logical ‘1’
switching it off is a logical ‘0’. A light sensitive device (LDR) receives the
signal and converts it back into original data. This method of using rapid pulses
of light to transmit data is called Visible Light Communication the basic
principle of VLC.
How Li-Fi Works?
There are many situations in which people get frustrated with the dull
performance signals of Wi-Fi at a place with many network connections in
seminars conferences etc. Li-Fi fulfils these needs .This fantabulous idea first
stroked the mind of Harald Haas from University of Edinburgh, UK, in his TED
Global talk on VLC. His idea was very simple that if the LED is “on” then the
digital 1 can be transmitted and if the led is “off” then the digital 0 can be
transmitted. Led’s can be switched on and off very quick. For transmitting
data this way all that we require is LED’s and controller that code data into
Led’s. Parallel data transmission can be done by using array of LED’s or by
using red, green, blue LED’s to alter light frequency with the frequency of
different data channel. Advancements and enhancements in this field generate
a speed of 10 gbps! But amazingly fast data rates and lowering band widths are
not the only reasons that enhance this technology. Lifi usually is based on light
and so it can be probably implemented in articrafts and hospitals that are prone
to inference from radio waves. Unlike Wi-Fi Li-Fi can work even underwater
which makes it more advantageous for military operations. Radio waves are
replaced by light waves in data transmission called Li- Fi.
Light emitting diodes can be switched on and off very much faster than the
human eye allowing the light source to appear continuously. The data
transmission is done through binary codes which involve switching on LED can
be done by logic 1 and switch off using logic 0.The encoding of information in
light can therefore be identified by varying the rate at which the LED’s flicker

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on and off to give strings of 0’s and 1’s.visible light communication is this
method of using rapid pulses of light to transmit information wirelessly.
To further get a grasp of Li-Fi consider an IR remote. 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, is capable of sending
thousands of such streams at very fast rate.
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.

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Li-Fi Construction:-
The Li-Fi product consists of 4 primary sub-assemblies:
• LED 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.
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

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Comparison With Other Technology
Li-Fi is the name which is used for wireless communication, similar to Wi-Fi.
Wi-Fi works well for general wireless coverage within buildings, and Li-Fi is
ideal for high density wireless data coverage inside a confined area or room and
for relieving radio interference issues. The Table given below shows a
comparison between wireless technologies. Wi-Fi currently offers high data
rates. The IEEE 802.11.n in most provides up to 150Mbit/s although practically,
very less speed is received.

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Applications:
There is a wide necessity for data transfer and by the end of the day every field
involves the use of technologies. One such technology is Li-Fi which can
have its applications extended in areas where the Wi-Fi technology lack its
presence like medical technology, powerplants and various other areas where
Li-Fi proved it excellence of the undersea awesomeness.
At present its applications are beyond imagination but still if to think about few
then they are :
 Can be used in the places where it is difficult to lay the optical fiber like
hospitals. In operation theatre LiFi can be used for modern medical
instruments.
 In traffic signals LiFi can be used which will communicate with the LED
lights of the cats and accident numbers can be decreased.
 Thousand and millions of street lamps can be transferred to LiFi lamps to
transfer data.
 In aircraft LiFi can be used for data transmission.
 It can be used in petroleum or chemical plants where other transmission
or frequencies could be hazardous.
 Replacement for other technologies as compare with other wireless
technology Li-Fi have great features, for money applications we can use
Li-Fi as wireless technology.

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Future Prospects
First applications of Li-Fi have been put to use already, for example, in
hospitals where RF signal are a threat due to interference problems with medical
equipment such as blood pumps and other
life supporting instruments. Axiomatic Europe presented such a product at the
Embedded World exhibition in Nurnberg, Germany. The prototype of a mobile
phone with an incorporated VLC
system was presented by Casio at the Consumer Electronics Show in Las Vegas
last year. In the coming years, we will see more Li-Fi products entering the
market, both in the industrial as well as consumer markets.
 Enhanced & Exclusive Shopping Experience
Imagine 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.
 You Might Just Live Longer
For a long time, medical technology has lagged behind the rest of the
wireless world. Operating rooms do not allow Wi-Fi over radiation
concerns, and there is also that whole lack of dedicated spectrum. While
Wi-Fi is in place in many hospitals, interference from cell phones and
computers can block signals from monitoring equipment. Li-Fi solves
both problems: lights are not only allowed in operating rooms, but tend to
be the most glaring (pun intended) fixtures in the room. And, as Haas
mentions in his TED Talk, Li-Fi has 10,000 times the spectrum of Wi-Fi,
so maybe we can delegate red light to priority medical data. Code Red!

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 Airlines ( Data on the go!)
Nothing says captive audience like having to 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 so far is that passengers will "soon" be offered a "high-
speed like" connection on some airlines. United is planning on speeds as
high as 9.8 Mbps per plane. Uh, I have twice that capacity in my living
room. And at the same price as checking a bag, I expect it. Li-Fi could
easily introduce that sort of speed to each seat's reading light.
 Smarter Power Plants
Wi-Fi and many other radiation types are bad for sensitive areas. Like
those surrounding power plants. But power plants need fast, inter-
connected data systems to monitor things like demand, grid integrity and
(in nuclear plants) core temperature. The savings from proper monitoring
at a single power plant can add up to hundreds of thousands of dollars.
Li-Fi could offer safe, abundant connectivity for all areas of these
sensitive locations. Not only would this save money related to currently
implemented solutions, but the draw on a power plant’s own reserves
could be lessened if they haven’t yet converted to LED lighting.
 Lightings Points Used as Hotspot:
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.
 Undersea Awesomeness:
Underwater ROVs, those favorite toys of treasure seekers and
James Cameron, operate from large cables that supply their power and
allow them to receive signals from their pilots above. ROVs work great,
except when the tether isn‘t long enough to explore an area, or when it
gets stuck on something. If their wires were cut and replaced with light —
say from a submerged, high-powered lamp — then they would be much
freer to explore. They could also use their headlamps to communicate
with each other, processing data autonomously and referring findings
periodically back to the surface, all the while obtaining their next batch of
orders.

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Advantages
 Li-Fi has low implementation and maintenance costs. High
data transmission rates of up to 10 Gbps can be achieved.
 It is safe for humans since light, unlike radio frequencies,
cannot penetrate human body.
 Efficiency: Data transmission using Li-Fi is very cheap
 A free band that does not need license.
 Availability: Availability is not an issue as light sources are
present everywhere.

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Limitations
 Only works if there is direct line of sight (LOS) between the
transmitter and receiver.
 Data transmission can be easily obstructed by opaque obstacles.
 The use of very high frequencies (400-800THz) limits it to very
short distances and
 Point to Point communications only.

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Conclusion
Li-Fi is the upcoming and on growing technology acting as competent for
various other developing and already invented technologies. Since light is the
major source for transmission in this technology it is very advantageous and
implementable in various fields that can’t be done with the Wi-Fi and other
technologies. Hence the future applications of the Li-Fi can be predicted and
extended to different plat- forms like education fields, medical field, industrial
areas and many other fields. 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
towards the cleaner, Greener, Safer and Brighter future.
Li-Fi has great technology in the field of wireless data transmission. It is
advanced Conventional methods of wireless communications that use light as
data carrier. Many Enhancements can be made to the existing technology, by
using fast-switching LEDs, data transmission rates can be further enhanced. The
driving speed of the circuit can be improved by using fastswitching transistors.
Li-Fi is feature key of high speed data transmission. If LI-FI technology can be
put into practical use, every bulb used to transmit a data and will lead toward
the brighter future.

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References
[1] Akshata M Sonnad, Anjanagopan, Sailakshmi N R, Divya S, Ambika R,
“Recent Advancements in li-fi Technology” International Journal of Electrical,
Electronics and Data Communication, volume-1, issue-10, dec-2013 issn: 2320-
2084.
[2] Balaramghosal , Asim Kumar Panda “li-fi a green energy initiative”
International Journal of Computer Applications (0975 – 8887) volume 95– no.
11 june 2014.
[3] Jay h. Bhut, Dharmrajsinh N. Parmar, Khushbu V. Mehta, Electronics &
Communication Engineering, Marwadi Education Foundation, Rajkot, India.
Communication system engineering,
[4] Rahul R. sharma1, Raunak2, Akshay Sanganal Department of Computer
Engineering fr.crit, Vashimumbai, India“li-fi technology transmission of data
through light”int. J. computer Technology & applications, vol 5 (1),150-154
issn:2229-6093.
[5] Kanchan Gupta, Kajal, Ashish saini, “lifi- light fidelity technology- a
review” international journal of emerging research in management &
technology issn: 2278-9359 (volume-3, issue-10).
[6] Vitthal S Saptasagare ,student M.tech, dept of cse, Canara Engineering
College, Mangalore, Karnataka “India next of wi-fi an future technology in
wireless networking li-fi using led over internet of things” international journal
of emerging research in management &technology issn: 2278-9359 (volume-3,
issue-3).

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