Lifi presentation

AUROBINDO INSTITUTE OF ENGG & TECH SHERIGUDA,IBRAHIMPATNAM,R.R DIST

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PRESENTATION ON

A FASTEST WIRELESS TECHNOLOGY BYG.REDDY VENKATESH126Z1A0403

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PRESENT SCENARIOINTRODUCTION TO LI-FIORIGIN OF LI-FIWHY ONLY VLCHOW LIFI WORKSAPPLICATIONS OF LI-FIADVANTAGES OF LI-FILIMITATIONS OF LI-FICONCLUSION

1.Present ScenarioDependent on internetSharing of dataInternet speeds quite annoyingWi-Fi uses radio waves from radio spectrumFreqency range < 300GHz EM wavesCongestion of radio spectrumYou tube

Limitations of wi-fi:Getting blocked slowlyIncreasing complexity

Are radio waves nt fine? Four issues Capacity EfficiencySecurityAvaliability

2.Introduction to Li-FiReplacing Rw with VLC

What is the need for LI-FI ?

What is Li-Fi ?It stands for light fidelityOptical version of wi-fiUses visible light (LED Light) instead of radio wavesComponent of IOT

How does it defer?Privides illumination as well as data transmissionBased on led for transfer of dataSpeed is incredibly high

Origin of Li-FiTechnology began during 1990sLifi came out from mind of Dr.Haas he calls it data through illumination He coined the term Lifi in 2011 at TED Global talk The research was initiated by consortium of universitiesDovelopment of LEDs is the biggest accomplishment

Is this proven technology ?Lifi is verified experimentallyProf Haas demonstrated at global talk on 12th july 2011 by transmission of video data @ 10MBps later he achieve 123MBps

Why only VLC ?VLC uses direct modulation and demodulationRadio technology is complexity It is a data communication medium, which uses visible light frequency range between 400THz(780nm)-800THz(375um)

EM Spectrum

Construction of VLC system Lifi product consists of 4 primary sub assembles

White LED Bulb (source of light)Radio freq power amplifier circuit Printed circuit board Enclosure

How does Lifi work ?Working Principle of Lifi :By varying the current through the LED at high speed we can vary the output at very high speeds It uses visible light for data communication For Ex : Imagine a Torch (Due to rapidity of motion of switching between on & off states torch appears to be on constantly) We should be able to see the light but we cant see the dataLEDs permitting us to send required data via light

Description of working process :Constant current is applied across the LEDs to use The light is detected by photo sensitive devicesLight is amplified & processed then fed to deviceLEDs varies in intensity so fast ; human cant detect it

WORKING-->

Continue.if LED is on=transmit 1

off=transmit 0Some LEDs & a controller is needed which can code data into those LEDs in order to setup the systemBy varying the rate(flickering) we encode the desired data

Modulation techniques used in Lifi:Lifi uses VL for sending data,for transmission modulation of the data necessaryOFDM(orthoganal freq-division multiplexing)OOK(on-off keying)PWM(pulse width modulation)PPM(pulse position modulation)SIM-OFDM(Sub carrier index modulation OFDM)Use of OLEDs(orthogonal light emitted diodes)

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Applications of Li-fi Lifi finds a varity of applications in many fields from access to internet .it can easily be used in all such places where blutooth,infrared,wifi & Internet are broadly in use. Some of applications represented below.Education systemInternet access in aircraftsTraffic lightsIntrinsically safe environmentOn ocean bedsIn the field of medicine

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Advantages Cheaper than wifi,since visible light spectrum is free bindNo license neededIt supports broadcasting of networkMobile connectivityIssues of shortage of radio freq bandwidth may be sorted out

It gives solutions to problems in wi-fi:CapacityEfficiencyAvailabilitySecurityConnectivity

Limitations of lifiLight waves can be easily blocked Light cant pass through solid objects such as walls & obstaclesLi-fi requres line of sightPresence of light is essentialLight cant approach the range of radio wavesInterference from external sources of light in path of transmission will cause interruption in communication

Conclusion

Future scope:We ulitimately run out of radio spectrumLi-fi can be used in each and every scenario without worry of spectrum shortageLi-fi can become one of the major technologies in near futureThe future of li-fi is Gi-fi or giga bit wireless communication

Any quarriesAny quarries.

*Praveeen