vlc and li-fi

1. 1
LITERATURE SURVEY PRESENTATION
DEPARTMENT OF ELECTRONICS
M.E.S. COLLEGE, MARAMPALLY

2. Presented by
Abhilash K.M
Haseen M.H
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3. Contents
 What is communication
 Access network
 Visible light communication
-Spectrum analysis
-Features
 LI-FI
-History
-working Process
 Advantages and disadvantages
 Application
 Conclusion
 Reference
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4.  FROM LATIN COMMUNICARE, MEANING TO SHARE.
 CONVEYING INFORMATION.
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5. Electronic communication
•Transmitter: is an electronic device which, with the aid of
an antenna , produces radio waves
•Channel : refers either to a physical transmission medium
such as a wire ,or to a logical connection over a
multiplexed medium such as radio channel
•Receiver: is an electronic device that receives radio wave
and converts the information carried by them to a usable
form
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6. AN ACCESS NETWORK IS THE PART OF A
TELECOMMUNICATIONS NETWORK WHICH
CONNECTS SUBSCRIBERS TO THEIR IMMEDIATE
SERVICE PROVIDER
1. Wired access
2. Wireless access
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7. Wired access
 Copper wire
-ISDN(Integrated Services Digital Network)
*speed- 2x64kbps
- DSL(Digital Subscriber Line)
- *speed- 8Mbps
 Optical fiber
-GPON(Gigabyte Passive Optical Network)
*speed- 10Gbps
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8. • Transfer of information between two or
more points that are not connected by an
electric conducter
Example : wi-fi, radio
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9.  Radio Spectrum is congested but the demand for
wireless data double each year .Every thing, it seems
want to use wireless data but the capacity is drying up.
 So what can carry this excess demand in the future .
1.4 Million
5 Billion
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11. The visible light communication (VLC)
refers to the communication
technology which utilizes the visible
light source as a signal transmitter, the
air as a transmission medium, and the
appropriate photodiode as a signal
receiving component.
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12. Radio
Waves
Infrared
Rays
Visible
Rays
Ultraviolet
Rays
X- Rays
Gama
Rays
 Gama rays cant be used as they could be dangerous.
X-rays have similar health issues.
Ultraviolet light is good for place without people, but
other wise dangerous for the human body.
Infrared, due to eye safety regulation, can only be used
with low power.
HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT
SPECTRUM.
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13. Visible light is the form in which
electromagnetic radiation with
wavelengths in a particular range is
interpreted by the human brain. Visible light
is thus by definition comprised of visually-
perceivable electromagnetic waves. The
visible spectrum covers wave lengths from
380 nm to 750 nm.
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14. Frequency spectrum 14

15. VISIBLE LIGHT COMMUNICATION PROCESS
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16. Transmitters:-
• LED
• Fluorescent Light
Receiver:-
• Photodiode
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17. A. Bandwidth: The visible light spectrum is plentiful(10,000 more than RF
spectrum), unlicensed.
B. High speed: Very high data rates can be achieved due to low
interference, high device bandwidths and high
intensity optical output.
C. Planning: Capacity planning is simple since there tends to be
illumination infrastructure where people wish to
communicate, and good signal strength
can literally be seen.
D. Low cost: Requires fewer components than radio technology.
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18. E. Energy: LED illumination is already efficient and the data
transmission requires negligible additional power.
F. Environment: RF transmission and propagation in water is
extremely difficult but Li-Fi works well in this environment.
G. Safe: Life on earth has evolved through exposure to visible
light. There are no known safety or health concerns for this
technology.
H. Non-hazardous: The transmission of light avoids the use of
radio frequencies which can dangerously interfere with
electronic circuitry in certain environments.
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21. LI-FI is transmission of data through illumination, sending
data through a LED light bulb that varies in intensity
faster than human eye can follow
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22. The technology truly began
during the 1990's in countries
like Germany, Korea, and
Japan where they
discovered LED's could be
retrofitted to send
information. Harald Haas
continues to wow the world
with the potential to use light
for communication
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23. •Li-Fi stands for ‘Light Fidelity’.
•Li Fi is now part of Visible Light Communication(VLC) PAN
IEEE 802.15.7 Standard.”Li-Fi is typically implemented using
white LED light bulbs”.
•These device are normally used for illumination by Appling
a constant current through the LED
•Li-Fi is the term have been used to label the fast and
cheap wireless communication system, which is the optical
version of Wi –Fi .
•Li-Fi is light based Wi-Fi that is, it uses light instead of radio
waves to transmit information
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25. • He explained ,”very simple, if the LED is on, you
transmit a 1 and when LED off transmit a 0.The LED
can be switched on and off very quickly, which
gives nice opportunities for transmitting data.”
• 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
encoding a different data channel.
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27. Advantages
 Larger bandwidth (10,000 times the radio bandwidth)
 High efficiency
 More availability
 Highly secure
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28. Disadvantages
 Presence of Light is essential
 There will be interference from sunlight
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31. 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 radio ways , li-fi is
introduced.
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33.  Visible Light is more safe than RF, hence it can be used in places
where RF can't be used such as petrochemical plants .
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34.  There are millions of street lamps deployed around the
world.
 Each of these street lamps could be a free access point.
STREET LAMPS ( AS FREE ACCESS POINTS )
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35. 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
hotspots to transmit wireless data.
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36. REFRENCES
[1] S. Haruyama, “Advances in Visible Light Communication Technologies,” 38th
Euro. Conf. and Exhibition on Optical Commun., 2012, paper We.3.B.5.
[2] IEEE Communications Magazine • December 2013 0163-6804/13/$25.00 ©
2013 IEEE
[3] J. A. J. Roufs and F. J. J. Blommaizt, “Temporal Impulse and Step Responses of
the Human Eye Obtained Psychophysically by Means of a Drift-Correction
Perturbation Technique,” Vision Research, vol. 21, no. 8, 1981, pp. 1203–21.
[4] “Solid-State Lighting Research and Development: Multi Year Program Plan,”
http://apps1.eere.energy.gov/buildings/
publications/pdfs/ssl/ssl_mypp2013_web.pdf, Apr. 2013.
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37. [5] Lighting the Way: Perspectives on the Global Lighting Market, 2nd ed.,
McKinsey & Company, 2012, http://www.mckinsey.com.
[6] International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7
No.11 (2012)
[7] T. Komine and M. Nakagawa, ”Fundamental Analysis for Visible- Light
Communication System using LED Lights”, IEEE Transactions on Consumer
Electronics, vol. 50, no. 1, Feb. 2004
[8] T. Komine and M. Nakagawa, “Fundamental analysis for visible-light
communication system using LED lights,” IEEE Trans. Consumer Electron., vol. 50,
no. 1, pp. 100–107, Feb. 2004.
[9] H. Elgala, R. Mesleh, and H. Haas, “Indoor broadcasting via white LEDs and
OFDM,” IEEE Trans. Consumer Electron., vol. 55, no. 3, pp. 1127–1134, Aug. 2009.
[10] J. Rufo, F. Delgado, C. Quintana, A. Perera, J. Rabadan, and R. Perez-
Jimenez, “Visible light communications for optical video transmission,” Microw.
Opt. Technol. Lett., vol. 52, no. 7, pp. 1572–1576, Jul. 2010.
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