Li fi Light Fiedility

Li –Fi Seminar Report Seminar Report 2014
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light-fidelity
ELECTRONICS & COMMUNICATION

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ABSTRACT
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.

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INDEX
SERIAL NO. PAGE NO.
CHAPTER 1 07-08
1.1 INTRODUCTION 07
CHAPTER 2 09-10
2.1 VISIBLE LIGHT COMMUNICATION 09
CHAPTER 3 11-14
3.1 LIGHT FIDELITY (LI-FI) 11
CHAPTER 4 15-17
4.1 SYSTEM DESIGN 15
4.2 METHODS OF VLC 15
CHAPTER 5 18-21
5.1 WORKING TECHNOLOGY 18
CHAPTER 6 22-24
6.1 COMPARISION BETWEEN LI-FI&WI-FI 22
6.2 ISSUES WITH RADIO WAVES 23
6.3 HOW IS LI-FI DIFFERENT 24
CHAPTER 7 25-31
7.1 FUTURE PROSPECTS 25
7.2 APPLICATIONS 26
CHAPTER 8 32-32
8.1 CONCLUSION 32
CHAPTER 9 33-33
9.1 BIBLIOGRAPHY 33
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List of figures
Figure no. Figure name Page no.
Fig 1.1 2.4 GHz Wireless Router 08
Fig 2.1 Electromagnetic spectrum 09
Fig 3.1 Coinage of LI-FI 11
Fig 3.2 Transfer of data through light 13
Fig 4.1 Communication system 16
Fig 5.1 Working of Li-fi 19
Fig 5.2 Block diagram 20
Fig 5.3 Transfer of data from internet to user 21
Fig 6.1 Four aspects of WI-FI 23
Fig 7.1 Anticipated uses of LI-FI 25
Fig 7.2 Use in medical field 27
Fig 7.3 Use in airlines 28
Fig 7.4 Use in power plants 29
Fig 7.5 Under sea awsomeness 30
Fig 7.6 Use of LI-FI in traffic control 31
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CHAPTER 1
1.1 INTRODUCTION
Li-Fi 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 by Harald
Haas in his TED Global talk on Visible Light Communication. ―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.Very simply, if the LED is on, you transmit a digital 1, if it‘s off
you transmit a 0.Haas says,―They can be switched on and off very quickly, which gives nice
opportunities for transmitted data.‖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 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 In October 2011 a number of companies and industry groups formed the Li-F
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. The consortium believes it is possible to achieve more than 10Gbps,
theoretically allowing a high-definition film to be downloaded in 30 seconds.
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
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limitations.
While Wi-Fi can cover an entire house, its bandwidth is typically limited to 50-100 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
Figure 1.1 . Linksys 2.4 Ghz Wireless Router
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.
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CHAPTER 2
2.1 VISIBLE LIGHT COMMUNICATION
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
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.‘
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 beamguiding, discovery or
generating an alarm for misalignment.
Fig 2.1 Electromagnetic spectrum
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.
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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, shortrange 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.
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CHAPTER 3
3.1 LIGHT FIDELITY(Li-Fi)
VLC represents only a fraction of what appears to be a much larger movement towards optical
wireless technologies in general. This larger word has been dubbed ‗Li-Fi‘ (Light Fidelity) by Dr
Harald Haas of Edinburgh University and organisations such as the Li-Fi Consortium.
Figure 3.1“Li Fi”- The Term Coined By Dr Harald Haas
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
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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’.
Li-Fi is a short term of light fidelity. Just like the more commonly known wireless fidelity,it
aims to transfer data through light. It is a technology based on LED‘s for the exchange of data.
Data will be sent via light, all kinds of light, regardless the part of the spectrum where they
belong. Li-Fi has been developed by Haas whose expertise is on the mobile communications
at Edinburgh University, known as the head over heels in LED from his teenage years.
In that connection, Li-Fi comprises several optical wireless technologies such as optical wireless
communication, navigation and gesture recognition applied for natural user interfaces .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 gigabitclass
to bridge the well-known spectrum 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.
Li-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 communication
speeds for short, medium and long ranges, and unidirectional and bidirectional data transfer
using line-of-sight or diffuse links, reflections 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.
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Fig 3.2 Transfer of data through light
Within a local Li-Fi cloud several databased services are supported through a heterogeneous
communication system. 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 giga-speed technologies, the Li-Fi Consortium defined GigaDock, GigaBeam, GigaShower,
GigaSpot and GigaMIMO models 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 communication speed over several metres.
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This is like watching TV channels or listening to different radio stations where no 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.
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CHAPTER 4
4.1 SYSTEM DESIGN
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-,data from the internet and local network is used to modulate the intensity of the
LED light source if any undetectable to the human eye. The photo detector picks up signal,
which is converted back into a data stream and sent to the client. The client can communicate
through its own LED output or over the existing network. An overhead lamp fitted with an LED
with signal-processing technology streams data embedded in its beam at ultra-high speeds to the
photo-detector. A receiver dongle then converts the tiny changes in amplitude into an electrical
signal, which is then converted back into a data stream and transmitted to a computer or mobile
device.
4.2 Methods of Visible Light Communication
 Devices used for Visible Light Communication
 Communication using Image Sensors
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Devices used for Visible Light Communication
Visible light
TRANSMITTER RECEIVER
Fig 4.1 Communication system
Transmitter devices of visible light communication
1.>Visible Light LED
 LED light intensity is modulated by controlling its current.
 Data rate: low speed to very high speed (up to several hundred Mbps)
2.> Fluorescent Lamp
 FSK modulation of high frequency fluorescent light.
 Data rate: up to several kilo bps.
Receiver devices of visible light communication
1.>PIN diode
A PIN diode is a diode with a wide, lightly doped 'near' intrinsic semiconductor region between a
p-type semiconductor and an n-type semiconductor region. The p-type and n-type regions are
typically heavily doped because they are used for Ohmic contacts.
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The wide intrinsic region is in contrast to an ordinary PN diode. The wide intrinsic region makes
the PIN diode an inferior rectifier (one typical function of a diode), but it makes the PIN diode
suitable for attenuators, fast switches, photo detectors, and high voltage power electronics
applications.
2.>Avalanche photodiode
An avalanche photodiode (APD) is a highly sensitive semiconductor electronic device that
exploits the photoelectric effect to convert light to electricity. APDs can be thought of as photo
detectors that provide a built-in first stage of gain through avalanche multiplication. From a
functional standpoint, they can be regarded as the semiconductor analog to photo multipliers .By
applying a high reverse bias voltage (typically 100-200 V in silicon), APDs show an internal
current gain effect (around 100) due to impact ionization (avalanche effect). However, some
silicon APDs employ alternative doping and beveling techniques compared to traditional APDs
that allow greater voltage to be applied (> 1500 V) before breakdown is reached and hence a
greater operating gain (>1000).In general, the higher the reverse voltage the higher the gain.
Communication through image sensors
An image sensor is a device that converts an optical image into an electronic signal. It is used
mostly in digital cameras, camera modules and other imaging devices. Early analog sensors were
video camera tubes; most currently used are digital charge-coupled device (CCD) or
complementary metal–oxide–semiconductor (CMOS) active pixel sensors.
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CHAPTER 5
5.1 WORKING TECHNOLOGY
VLC uses visible light between 400 THz (780 nm) and 800 THz (375 nm) as optical carrier for
data transmission and illumination. It uses fast pulses of light to transmit information wirelessly.
The main components of this communication system are
1) a high brightness white LED, Which acts as a communication source and
2) a silicon photodiode which shows good response to visible wavelength region serving as the
receiving element.
LED can be switched on and off to generate digital strings of 1s and 0s. Data can be encoded in
the light to generate a new data stream by varying the flickering rate of the LED. To be clearer,
by modulating the LED light with the data signal, the LED illumination can be used as a
communication source. As the flickering rate is so fast, the LED output appears constant to the
human eye. A data rate of greater than 100 Mbps is possible by using high speed LEDs with
appropriate multiplexing techniques. VLC data rate can be increased by parallel data
transmission using LED arrays where each LED transmits a different data stream. There are
reasons to prefer LED as the light source in VLC while a lot of other illumination devices like
fluorescent lamp, incandescent bulb etc. are available.
Very simply, if the LED is on, you transmit a digital 1, if it‘s off you transmit a 0,‖Haas says,
―They can be switched on and off very quickly, which gives nice opportunities for transmitted
data.‖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 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
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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.
Figure 5.1 Working of LI-FI
So what you require at all are 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.
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
International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012)©
Research India Publications; http://www.ripublication.com/ijaer.htm each frequency encoding is
a different data channel. Such advancements promise a theoretical speed of 10 Gbps –meaning
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you can download a full high-definition film in just 30 seconds. Simply awesome! But blazingly
fast data rates and depleting bandwidths worldwide are not the only reasons that give this
technology an upper hand. Since Li-Fi uses just the light, it can be used safely in aircrafts and
hospitals that are prone to interference from radio waves. This can even work underwater where
Wi-Fi fails completely, thereby throwing open endless opportunities for military operations.
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 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.
Figure 5.2 Block Diagram
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
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
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enables a kind of data transmission using binary codes. 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 it‘s potential to compete
with conventional Wi-Fi has inspired the popular characterisation Li-Fi.
Fig 5.3 Data from internet to user through light
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CHAPTER 6
6.1 COMPARISION BETWEEN LI-FI&WI-FI
LI-FI is a term of one used to describe visible light communication technology applied to high
speed wireless communication. It acquired this name due to the similarity to WI-FI, only using
light instead of radio WI-FI is great for general wireless coverage within buildings, and li-fi is
ideal for high density wireless data coverage in confined area and for relieving radio interference
issues, so the two technologies can be considered complimentary.
Table 6.1Comparison between current and future wireless technologies
The table also contains the current wireless technologies that can be used for transferring data
between devices today, i.e. Wi-Fi, Bluetooth and IrDA. Only Wi-Fi currently offers very high
data rates. The IEEE 802.11.n in most implementations provides up to 150Mbit/s (in theory the
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standard can go to 600Mbit/s) although in practice you receive considerably less than this. Note
that one out of three of these is an optical technology.
6.2 ISSUES WITH WI-FI USING RADIO WAVES
There are four issues with the current wi-fi scenario , which are :-
Fig 6.1 Four aspects of WI-FI
1.>CAPACITY:
 We transmit wireless data is by using electromagnetic waves -- inparticular, radio waves.
 Radio waves are scarce, expensive and we only have a certain range of it.
 Due to this limitation one can’t forever hope to cope with the demand of wireless data
transmissions and the number of bytes and data which are transmitted every month.
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2.>EFFICIENCY
 There are 1.4 million cellular radio masts deployed worldwide.
 Most of the energy consumed, is not used to transmit the radio waves,but is used to cool
the base stations.
 The efficiency of such a base station is only at about five percent.
3.>AVAILABILITY
 Availability of radio waves or RW signals causes another concern
 We have to switch off our mobile devices in aero planes
 It is not advisable to use mobiles at places like petrochemical plants and petrol pumps
4.>SECURITY
 The radio waves penetrate through walls.
 They can be intercepted, and somebody can make use of one‘s network.
6.3 How LI-FI is different?
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 of light, no matter the part of the spectrum that they belong. That is, the light
can belong to the invisible, ultraviolet or the visible part of the spectrum. Also, the speed of the
internet is incredibly high and you can download movies, games, music etc in just a few minutes
with the help of this technology. Also, the technology removes limitations that have been put on
the user by the Wi-Fi. You no more need to be in a region that is Wi-Fi enabled to have access to
the internet. You can simply stand under any form of light and surf the internet as the connection
is made in case of any light presence. There cannot be anything better than this technology.
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CHAPTER 7
7.1 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. Axiomtek 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 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.
Fig 7.1 Anticipated uses of VLC Technology
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7.2 APLICATIONS
7.2.1 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.
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7.2.2 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!
Figure 7.2 Use In Medical Field
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7.2.3 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. I‘ll be the guy WoWing next to you. Its better than listening to you tell me about
your wildly successful son, ma‘am.
Figure 7.3 Use in airlines
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7.2.3 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 theyhaven‘t yet converted to LED lighting.
Figure 7.4 Use in power plants
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7.2.4 Undersea Awesomeness
Underwater ROVs, those favourite 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.
Figure 7.5 Under sea awesomeness
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7.2.5 It Could Keep You Informed and Save Lives
Say there‘s an earthquake in New Delhi,or a hurricane. Take your pick — it‘s a wacky city. The
average Delhiite may not know what the protocols are for those kinds of disasters. Until they
pass under a street light, that is. Remember, with Li-Fi, if there‘s light, you‘re online. Metro
stations and tunnels, common dead zones for most emergency communications, pose no
obstruction. Plus, in times less stressing cities could opt to provide cheap high-speed Web access
to every street corner.
Figure 7.6 Use of li fi in traffic control
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CHAPTER 8
8.1 CONCLUSION
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 any 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.
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CHAPTER 9
9.1 Bibliography
1. www.wikisedia.com
2 www.visiblelightcomm.com/
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/
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