Lifi TECHNOLOGY REPORT

SAE, Computer Engineering 1 2014-15
Sinhgad Technical Education Society’s
Sinhgad Academy of Engineering, Kondhwa (Bk.), Pune.
Seminar and Technical Communication
Seminar
ON
Li-fi Technology
By
Mr. Onkar Bhujbal 27
Third Year
Department of Computer Engineering
Year 2014-15.

DEPARTMENT OF COMPUTER ENGINEERING
STES’S SINHGAD ACADEMY OF ENGINEERING
KONDHAWA BK, OFF SASWAD ROAD, PUNE 48
CERTIFICATE
This is to certify that the seminar report entitles
“Li-Fi Technology”
Submitted by
Mr. Onkar Bhujbal T120434226
Is a bonafide work carried out by him under the supervision of Prof. S.
R. Pawara and it is submitted towards the fulfillment of the requirement of STCL (TE
Computer Engineering).
Prof. S. R. Pawara Prof. B.B.Gite Prof. A.S.Chanchlani
Internal Guide Head,
Dept. of ComputerEngineering Dept. of ComputerEngineering Seminar
Coordinator
SAE, Pune SAE, Pune SAE, Pune
Place: Pune
Date:

ACKNOWLEDGEMENT
I would like to take this opportunity to thank all the people who were part of this
seminar in numerous ways, people who gave un-ending support right from the initial
stage. In particular, I wish to Thank.
Lecturer Mrs. S. R. Pawara my internal seminar guide who gave their co-operation
timely and precious guidance without which this seminar would not have been a success.
I thank them for reviewing the entire seminar with painstaking efforts and more of her,
uncanning ability to spot the mistakes.
I would like to thank our H.O.D. Prof. B. B. Gite for his continuous encouragement and
support and guidance at each and every stage of seminar.
And last but not the least I would like to thank all my friends who were Associated with
me and helped me in preparing my seminar The Seminar named Li-fi Technology
would not been possible without the extensive support of people who were directly or
indirectly involved in it.
Mr. Onkar Bhujbal (27)

Contents
DEPARTMENT OF COMPUTER ENGINEERING...................................................................2
STES’S SINHGAD ACADEMY OF ENGINEERING..................................................................2
1. ABSTRACT............................................................................................................. 6
2. INTRODUCTION........................................................................................................7
3. LITERATURE SURVEY ............................................................................................ 8
4. WORKING TECHNOLOGY ...................................................................................... 9
4.1 VisibleLightCommunication(VLC)-“A potential solutiontothe global wireless
spectrum shortage”..................................................................................................... 10
4.2 Present Scenario: ................................................................................................... 12
4.3 Light for Wi-Fi communication........................................................................... 13
4.4 CONSTRUCTION ..................................................................................................... 14
4.5 COMPARISION BETWEEN Li-Fi & Wi-Fi..................................................................... 15
4.4 How it is different? ........................................................................................... 16
5. APPLICATIONS OF LI-FI........................................................................................ 18
1. Hospitals................................................................................................................. 18
2. Airlines ................................................................................................................... 18
3. Smarter Power Plants:.............................................................................................. 19
4. Undersea Awesomeness:.......................................................................................... 19
5. It Could Keep You Informed and Save Lives................................................................ 19
6. USES IN VARIOUSAREAS........................................................................................... 20
6. ADVANTAGES OF LIFI....................................................................................... 21
7. LIMITATIONS...................................................................................................... 22
8. FUTURE ENHANCEMENTS................................................................................ 23
8.1 LED light bulb 'li-fi' closer, say Chinese scientists: ..................................................... 23
8.2 Unlimited capacity.................................................................................................. 24
CONCLUSION.............................................................................................................. 25
REFERENCES.............................................................................................................. 26

Figure 1 -DATA TRANSMISSION USING LED ............................................................. 11
Figure 2-Electromagnetic Spectrum.................................................................................. 13
Figure 3-Primary Sub-assemblies ..................................................................................... 14
Figure 4- Table: Comparison between current and future wireless technology .................... 16

1. 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.
What if we can use waves other than Radio waves to surf the internet? Radio
wave seems to be fully exploited and other spectrum needed to be explored. 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.
LIFI 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,
Smartphone’s, and tablets is transmitted through the light in a room. And security would
be a strong. (If you can’t see the light, you can’t access the data.).

2. 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. 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, who is considered to be the
father of Li-fi from university of Edinburgh, UK 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 arise 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.

3. LITERATURE SURVEY
It was July,2011 , Dr. Harald Hass ,Professor , mobile communication ,University of
Edinburgh, publicly demonstrated Light fidelity for the first time, a method of Visible
light communication (VLC) technology. Further Researchers at the Heinrich Hertz
institute in Berlin, Germany have reached data rates of over 500 MBPS using a standard
white light LED. Dr. Herald Hass also has setup a spin-off firm to sell a VLC transmitter.
Even more sophisticated and advance techniques are undergoing development at the
University of oxford and the University of Edinburgh. Teams from University of oxford
and University of Edinburgh are focusing on parallel data transmission using arrays of
LEDs, where each LED transmits a different data stream while other groups are mixtures
of red, green and blue LEDs to alter the light’s frequency, with each frequency encoding
a data channel.
Today researchers are working for its feasibility and designing the hardware
equipment required for making the technology robust and usable. Li-FI- technology has
higher potential, it is very much possible to transmit the data via light by changing the
flicker rate that provide different strings of 1 and 0, and its intensity is modulated so
quickly that the human eyes cannot notice. There are around 19 billion light emits
worldwide. Which in turns may be replaced by LED, i.e. potential source of transmitting
data? “At the heart of this technology is a new generation of high brightness (LED) light
emitting diodes,” says Herald Hass, from the University of Edinburg, U.K. Very simply,
if the LED is on, you transmit a digital 1 if it’s off, you transmit a 0, “They can be
switched on and off very quickly, which gives nice opportunities for connectivity and
transfer the data very quickly, efficiently and accurate without any external hindrances.

4. WORKING TECHNOLOGY
This brilliant idea was first showcased by Harald Haas from University of
Edinburgh, UK, in his TED Global talk on VLC. He explained,” 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.” 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 each frequency encoding a different data channel. Such
advancements promise a theoretical speed of 10 Gbps – meaning 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. 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 it’s potential to compete with conventional Wi-Fi has
inspired the popular characterization Li-Fi.
4.1 Visible Light Communication (VLC)-“A potential solution to the global
wireless spectrum shortage”
Li-Fi (Light Fidelity) is a fast and cheap optical version of Wi-Fi, the technology
of which is based on Visible Light Communication (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 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.

Figure 1 -DATA TRANSMISSION USING LED [1]

4.2 Present Scenario:
 We have 1.4 million cellular mast radio waves base stations deployed
 We also have over 5 billion of mobile phones
 Mobile phone transmits more than 600 Tb of data
 Wireless communication has become a utility like electricity & water
 We use it in our everyday life, in our private life, business life
 Currently Wi-Fi uses Radio Waves for communication
 It is important to look into this technology which has become fundamental to our
life
Four Issues with radio waves
1. Capacity :
 We transmit wireless data through radio waves
 Radio waves are limited
 Radio waves are scar and expensive
 We only have a certain range of it
 With the advent of the generation technology as of like of 2.5G,3G,4G
and so on we are running out of spectrum.
2. Efficiency :
 There are 1.4 million cellular radio base stations
 They consume massive amount of energy
 Most of this energy is not use for transmission but for cooling down the
base stations
 Efficiency of such a base station is only 5% and that raise a very big
problem
3. Availability :
 Availability of radio waves or rf signals causes another concern
 We have to switch off our mobiles In aero planes
 It is not advisable to use mobiles at places like petrochemical plants and
petrol pumps
4. Security :
 Radio waves penetrates through walls
 They can be intercepted

 If someone has a knowledge and bad intentions than he may misuse it
Alternative to radio waves in Electromagnetic spectrum
a. So there are four major concerns i.e., capacity, efficiency, availability and
security related with radio waves
b. But on the other hand we have 40 billion of light box already installed and light
is part of electromagnetic spectrum
c. So let’s look up at this in context of EM spectrum
Radio
waves
Infra-red Visible Ultra violet X rays Gamma
rays
Electromagnetic spectrum
 Gamma rays are simply very dangerous and thus can’t be used for our purpose
of communication
 X-rays are good in hospital and can’t be used either
 Ultra –violet rays are sometimes good for our skin but for long duration it is
dangerous
 Infra-red rays are bad for our eyes and are therefore use at low power levels
 We have already seen shortcoming of radio waves
So we are left with only visible light spectrum.
Figure 2-Electromagnetic Spectrum
4.3 Light for Wi-Fi communication
 Light has been around for millions of years.
 It has created us, has created life and has created all stuffs of life.

 FLICKERING lights are annoying but they may have an upside. Visible light
communication (VLC) uses rapid pulses of light to transmit information
wirelessly, now it may be ready to compete with conventional WIFI.
 So it is inherently safe use and would be great if we can use it for our wireless
communication.
What we have to do?
 We have to replace inefficient fluorescents lights with this new dignitaries
of LED lights.
 It is a semi conductive e-device.
 The LED bulb will hold a microchip that will do the job of processing the
data.
Light intensity can be modulated at very high spends to send data tiny changes in
amplitude.
4.4 CONSTRUCTION
The LIFI product consists of 4 primary sub-assemblies:
Figure 3-Primary Sub-assemblies [2]
• BULB
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure

a) An RF (radio-frequency) signal is generated by the solid-state PA and is guided
into an electric field about the bulb.
b) The PCB controls the electrical inputs and outputs of the lamp and houses the
microcontroller used to manage different lamp functions.
c) The high concentration of energy in the electric field vaporizes the contents of
the bulb to a plasma state at the bulb’s centre; this controlled plasma generates
an intense source of light.
4.5 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.

Figure 4- Table: Comparison between current and future wireless technology [4]
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 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.
4.4 How it 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.

5. APPLICATIONS OF LI-FI
1. Hospitals
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, I don’t know, delegate red
light to priority medical data. Code Red!
2. Airlines
Airline Wi-Fi. Ugh. 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. It’s better than listening to you tell me about your wildly
successful son, ma’am.

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 they haven’t yet converted
to LED lighting.
4. 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.
5. It Could Keep You Informed and Save Lives
Say there’s an earthquake in New York. Or a hurricane. Take your pick — it’s a wacky
city. The average New Yorker 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. Subway 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.
6. USES IN VARIOUS AREAS
Can be used in the places where it is difficult to lay the optical fiber like hospitals. In
operation theatre Li-Fi can be used for modern medical instruments. In traffic signals
Li-Fi can be used which will communicate with the LED lights of the cars and accident
numbers can be decreased. Thousand and millions of street lamps can be transferred to
Li-Fi lamps to transfer data. In aircraft Li-Fi can be used for data transmission.
It can be used in petroleum or chemical plants where other transmission or
frequencies could be hazardous.

6. ADVANTAGES OF LIFI
1) Wi-Fi is great for general wireless coverage while Li-fi is ideal for high density
coverage in a confined region.
2) It is believed that the technology can yield a speed more than 10 Gbps,
allowing a HD film to be downloaded within 30 seconds.
3) Mostly powered by LEDS so it is cost efficient.
4) Its main advantage is its bandwidth. It is 10,000times faster than radio waves.
5) Transmission of data is fast and easy.
6) High installment cost but very low maintenance cost.
7) Longevity of LED bulb: saves money.
8) Light doesn’t penetrate through walls: secured access.
9) Low electricity cost.

7. LIMITATIONS
1) Light can't pass through objects
2) Interferences from external light sources like sun light, normal bulbs, and opaque
materials in the path of transmission will cause interruption in the
communication.
3) High installation cost of the VLC systems
4) A major challenge facing Li-Fi is how the receiving device will transmit back to
transmitter. Still there are some backdrops like it can only transmit when in the
line of sight well it can be sorted out someday or incoming days I hope. There
has been a lot of early, and there are some very good applications.
5) Although this technology sounds like a replacement to Wi-Fi but this high speed
data transferring technology also has some limitations that is the inability of light
to pass through obstacles.

8. FUTURE ENHANCEMENTS
The first VLC smartphone prototype was presented at the Consumer Electronics
Show in Las Vegas from January 7–10 in 2014. The phone uses Sun Partner's Wysips
CONNECT, a technique that converts light waves into usable energy, making the
phone capable of receiving and decoding signals without drawing on its battery. A
clear thin layer of crystal glass can be added to small screens like watches and
smartphones that make them solar powered. Smartphones could gain 15% more
battery life during a typical day. This first smartphones using this technology should
arrive in 2015. This screen can also receive VLC signals as well as the smartphone
camera. The cost of these screens per smartphone is between $2 and $3, much cheaper
than most new technology.
Philips lighting company has developed a VLC system for shoppers at stores.
They have to download an app on their smartphone and then their smartphone works
with the LEDs in the store. The LEDs can pinpoint where they are located in the store
and give them corresponding coupons and information based on which aisle they are
on and what they are looking at.
The possibilities are numerous and can be explored further. If this technology
can be put into practical use, every bulb can be used something like a Wi-Fi hotspot to
transmit wireless data and we will proceed toward the cleaner, greener, safer and
brighter future.
Using an array of LEDs for parallel data transmission or using mixture of red,
green and blue LEDs to alter the light’s frequency with each frequency encoding a
different data channels. Such advancements promise a theoretical speed of 10 Gbps -
meaning one can download a full high definition film in just 30 seconds.
8.1 LED light bulb 'li-fi' closer, say Chinese scientists:
If "li-fi" technology takes off, all LED lights could potentially provide internet
connectivity. Wi-Fi connectivity from a light bulb - or "li-fi" - has come a step
closer, according to Chinese scientists. A micro chipped bulb can produce data speeds

of up to 150 megabits per second (Mbps), Chi Nan, IT professor at Shanghai's Fudan
University told Xinhua News.
A one-watt LED light bulb would be enough to provide net connectivity to four
computers, researchers say. There are no supporting video or photos showing the
technology in action.
Li-fi, also known as visible light communications (VLC), at these speeds would be faster
- and cheaper - than the average Chinese broadband connection.
In 2011, Prof Harald Haas, an expert in optical wireless communications at the
University of Edinburgh, demonstrated how an LED bulb equipped with signal
processing technology could stream a high-definition video to a computer. He coined
the term "light fidelity" or li-fi and set up a private company, PureVLC, to exploit the
technology.
This year, the Fraunhofer Heinrich Hertz Institute claimed that data rates of up to 1Gbit/s
per LED light frequency were possible in laboratory conditions, making one bulb with
three colors potentially capable of transmitting data at up to 3Gbit/s.
8.2 Unlimited capacity
Li-fi promises to be cheaper and more energy-efficient than existing wireless radio
systems given the ubiquity of LED bulbs and the fact that lighting infrastructure is
already in place.
Visible light is part of the electromagnetic spectrum and 10,000 times bigger than the
radio spectrum, affording potentially unlimited capacity. But there are drawbacks: block
the light and you block the signal. However, this is also a potential advantage from a
security point of view. Light cannot penetrate walls as radio signals can, so drive-by
hacking of wireless internet signals would be far more difficult, if not impossible.
Prof Chi's research team includes scientists from the Shanghai Institute of Technical
Physics at the Chinese Academy of Sciences, the report says. She admitted that the
technology was still in its infancy and needed further developments in microchip design
and optical communication controls before it could go mass market.

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.

REFERENCES
[1] http://students-addaa.blogspot.in/2013/09/li-fi-technology.html
[2] http://lizping.tumblr.com/post/80144182746/technology-how-do-lifi-light-source-work
[3] seminarprojects.com/s/seminar-report-on-lifi
[4] http://en.wikipedia.org/wiki/Li-Fi
[5] www.lificonsortium.org/
[6]”Visible-light communication: Tripping the light fantastic: A fast and cheap optical
version of Wi-Fi is coming”, Economist, dated 28Jan 2012.
[7] http://gimt.edu.in/clientFiles/FILE_REPO/2012/NOV/23/1353645362045/69.pdf
[8] https://www.youtube.com/watch?v=WRG9iXZbuAc
[9] http://purelifi.com/

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