Transcript
Name : SYED IMRAN ABBASRoll no : 1314321086
INTRODUCTION
• Li-Fi (Light Fidelity) The future technology In Wireless communication .• LI-FI is transmission of data through illumination , i.e sending data through a
LED light bulb that varies in intensity faster than human eye can follow.• Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light instead of
radio waves to transmit information.• 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.
HISTORY
• Professor Harald Haas, from the University of Edinburgh in the UK, is widely recognized as the original founder of Li-Fi.
• The technology truly began during the 1990's in countries like Germany, Korea, and Japan where they discovered LED's could be used to send information.
• Research into this has been conducted in earnest since 2003, mainly in the UK, US, Germany, Korea and Japan. Experiments have shown that LEDs can be electronically adapted to transmit data wirelessly as well as to provide light.
• It was here in 2007 that Professor Harald Haas’s research assistant, Mostafa Afgani, first sent data using light signals.
BASIC CONCEPT
• LED i.e Light emitting diode can be switched on and off very fast ( As operating speed of LED is less than 1 μs) which can’t be detected by human eye, causing the light source to be appear continuous.
• This invisible on-off activity enables a kind of data transmission using binary codes. Switching on and LED is a logical ‘1’, switching it off is a logical ‘0’.
• It is possible to encode data in the light by varying the rate at which LED’s flicker on and off to give different strings of 1s and 0s. Modulation is so fast that human eye doesn’t notice.
HOW “LI-FI” WORKS
ISSUES REGARDING RADIO SPECTRUM
1. Capacity :• Less bandwidth as compared to other spectrum.• Insufficient spectrum for increasing data.2.Efficiency :• Millions of base stations consume huge amount of energy for :a) Transmitting the radio waves.b) To cool the base station cabins.• 5% efficiency.
ISSUES REGARDING RADIO SPECTRUM
3.Availability : • Available within a range of base stations.• Unavailable in aircrafts.• Unavailable in many industries.4.Security :• Less secure (passes through walls).
WHY ONLY VLC
• Gama rays cant be used as they are 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 ARE LEFT WITH ONLY THE VISIBLE - LIGHT SPECTRUM.
Radio Waves
Infrared Rays
Visible Rays
Ultraviolet Rays X- Rays
Gama Rays
LI-FI VS WI-FI
POTENTIAL APPLICATIONS OF LI-FILi-Fi technology is still in its infancy .However
some areas where it seems perfectly applicable are:-• Traffic Lights :Traffic lights can communicate to the car and
with each other. Cars have LED-based headlights, LED-based back lights, and cars can communicate with each other
and prevent accidents in by exchanging information.
POTENTIAL APPLICATIONS OF LI-FI
• INTRINSICALLY UNSAFE ENVIRONMENT : Visible Light is more safe than RF, hence it can be used in places where RF can't be used such as petrochemical plants .
POTENTIAL APPLICATIONS OF LI-FI
• Airlines :Whenever we travel through airways we face the problem in communication media ,because the whole airways communication are performed on the basis of radio waves. To overcomes this drawback on radioways,
li-fi is introduced.
POTENTIAL APPLICATIONS OF LI-FI
• ON OCEAN BEDS : Li-Fi can even work underwater were Wi-Fi fails completely, thereby opening endless opportunities for military/navigation operations.
ADVANTAGES OF USING LI-FI
• Data rate greater than 10 Gbps, Theoretically allowing HD film to be downloaded in 30 seconds.
• Can be used anywhere, even in RF restricted areas, Since light waves will not interfere with radio waves.
• Mostly LED light bulbs are used, which consumes less energy. Hence cost efficient.
• As light waves cannot penetrate through walls, the data cannot be intercepted, Thus provides secured communication.
• Efficient alternative to radio based wireless since it is quick and reliable.
CONCLUSION
Thus, if Li-Fi technology can be put into practical use, every bulb can be
used as an alternative to Wi-Fi hotspots. It provides simple, faster and
efficient wireless data communication. And I believe Li-Fi will enable us to
proceed towards a cleaner, greener, safer and brighter future.
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