Presentation On

Li-Fi(Light Fidelity)Technology

Presented To: Presented By : Er. Neeru Name: Abhilash

Er. Lalit Roll No:5511203

Branch – CSE

Semester 5th 1

CONTENTSIntroductionPresent ScenarioHistoryWorking of Li-FiBasic Principle Of Li-FiComparison between Li-Fi & Wi-FiHow Is It DifferentEconomic ValueLimitationsApplication of Li-FiFuture ProspectsConclusionReferences 2

IntroductionLi-Fi is a label for wireless-communication systems using

light as a carrier instead of traditional radio frequencies, as in Wi-Fi.

The term was first used in this context by ‘Harald Haas’ from the University of Edinburgh in his TED Global talk on Visible Light Communication.

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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Fig 1. A Li-Fi Zone4

History

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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Fig 2. Professor Harald Hass

Present Scenario

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1.4 Million 5 Billion

Present Scenario

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 .

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WHAT CAN REPLACE

RADIO WAVES FOR WIRELESS

COMMUNICATION ?

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Working of Li-Fi

Operational procedure is simple : if the LED is on, you transmit a digital signal 1, if it’s off you transmit a 0 signal.

The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. Hence all that us required is 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 LED’s for parallel data transmission.

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11Fig 3. Working Of Li-Fi

Visible Light Communication (VLC)

Visible Light Communication (VLC) is the basic principle behind Li-Fi.

It uses visible light between 400 THz (780 nm) and 800 THz (375 nm) as optical carrier for data transmission and illumination.

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.

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Why VLC ??

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. 13

Fig 4. Electromagnetic Radiation

Li-Fi Vs Wi-Fi

14Table 1. List Of Various Technologies

15Fig5. DATA Transmission Using Li-Fi

ECONOMIC VALUE

A free band that does not need license.High installment cost but very low maintenance

cost.Cheaper than Wi-Fi.Theoretical speed up to 1 GB per second : Less

time & energy consumption.No more monthly broadband bills.Lower electricity costs.Longevity of LED bulb : saves money.Light doesn't penetrate through walls : secured

access.16

LimitationsThe main problem is that light can't pass through objects, so if the receiver

is inadvertently blocked in any way, then the signal will immediately cut out. "If the light signal is blocked, or when you need to use your device to send information -- you can seamlessly switch back over to radio waves".

Reliability and network coverage are the major issues to be considered by the companies while providing VLC services. Interferences from external light sources like sun light, normal bulbs; and opaque materials in the path of transmission will cause interruption in the communication.

High installation cost of the VLC systems can be complemented by large-scale implementation of VLC though Adopting VLC technology will reduce further operating costs like electricity charges, maintenance charges etc.

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APPLICATION OF LI-FI

In Traffic Lights

Airlines

Smarter Power Plants

Undersea Awareness

In Hospitals

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Fig 5. Light bulbs in a remote area

20Fig 6. Underwater Li-Fi application.

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Fig 7.Traffic Lights a source of Li-Fi

Future Prospects

This research report categorizes the global VLC technology market; based on component, applications, and geography. Li-Fi uses light-emitting diodes (LEDs) which are rapidly gaining in popularity for standard light bulbs and other domestic and commercial purposes. They are expected to be ubiquitous in 20 years

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CONCLUSION

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.

23Fig 8. Simple LED

References

Google

Wikipedia

Slideshare

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THANK YOU

Any Queries ???

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