Light fidelity (li fi)

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LI FI A NEW GENERATION TECHNOLOGY

Guided by : Mr. Sarbeswara Hota.(Assistant Professor,Dept. of CA ,iter)

Presented by : Vivekananda Sahoo. (1461020014,4th sem,MCA ,iter)

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CONTENTS :

• Introduction• Present senario• Working principle• Construction• Advantages• Application area• Limitation• Conclussion• References

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INTRODUCTION :What is LI-FI ?

It is a “Wireless Optical Networking Technology”. As it uses light for transmission of data and the

operation of whole system is depends on precise transmission of data through light.

Therefore, this system is termed as “Li-Fi”. Professor Harald

Haas(germany,University of Edinburg) is the architect of Li-Fi system.

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Li-Fi technology uses visible light spectrum for transmission of data.

Due to use of Visible light spectrum Li-Fi system has larger bandwidth as compared to other systems.

It is the fast and cheap Wireless communication system which is optical version of Wi-Fi.

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.

Present Scenario: Radio Spectrum is congested but the demand for wireless data double each year.At present we have as many as 1.5 million radio wave base stations across the globe.We also have close to 5 billion mobile connections which transmit a data over 600TB.Wireless communication has become an utility like electricity and water.

1.4 BILLION

5 BILLION

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ISSUES WITH RADIO WAVE :

• Capacity• Efficiency• Availability• Security

“ SO WE HAVE TO THINK ABOUT AN ALTERNATIVE WAY TO HANDEL THE CHALLENGE ”

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Who can replace the radio wave for wireless communication ?

Solution is VLC (Visual Light Communication)

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WHY ONLY VLC ?

• electromagnetic spectrum :-

Gamma rays are simply dangerous • X-rays are good in hospitals • Ultra violet ray for our skin is dangerous• Infrared rays are bad for our eyes• So we are now left with Visible Rays.

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How it works :• In simple terms, Li-Fi can be thought of as a light-

based Wi-Fi. That is, it uses light instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi would use transceiver-fitted LED lamps.

• The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data.

• Operational procedure is very simple.• Normal light power is replaced by LED light power.

• If LED is ON, digital data ‘1’ is transmitted & if LED is OFF, digital data ‘0’ is transmitted.• LEDs varies in intensity so fast that a human eye cannot detect it.• On one end all the data on the internet will be streamed to a lamp driver when the led is turned on the microchip converts the digital data in form of light .• A light sensitive device (photo detector) receives the signal and converts it back into original data. This method of using rapid pulses of light to transmit information wirelessly is technically referred as Visible Light Communication .

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Operational diagram :

• Transmission side simply contains LED or fluorescent lamp.

• Receiver end contains photo-diode & image sensor.

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Construction : The LiFi product consists of 4 primary sub-

assemblies:BulbRF Power Amplifier Circuit (PA)Printed Circuit Board (PCB)Enclosure

(Block diagram)

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• The PCB controls the electrical inputs and outputs of the lamp and houses the microcontroller used to manage different lamp functions.

• An RF (radio-frequency) signal is generated by the solid-state PA and is guided into an electric field about the bulb.

• The high concentration of energy in the electric field vaporizes the contents of the bulb to a plasma state at the bulb’s center; this controlled plasma generates an intense source of light.

• All of these subassemblies are contained in an aluminum enclosure.

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ADVANTAGES:

• Larger bandwidth ( 10,000 times the radio bandwidth ).

• High speed data rate .• High efficiency .• Highly secure.• Works even under water in sea.• Safe for health .• More availability.• Low cost solution.

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APPLICATION AREAS :• RF restricted environment – visible light is safe

enough that can be used in petrochemical plants, nuclear power plants.

• Airways – The whole airways communication are performed on the basis of radio waves.To overcome this drawback lifi can be introduced.

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• Hospital – The sensitive electronic equipment may be interfered on the presence of radio frequency. So here lifi can be used.

• Underwater – Lifi can even work under water where wifi fails completely . It is an opportunity for military , research, navigation system.

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• In seminar hall :

• Street lamps as open hotspot :

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LIMITATIONS :• light cannot pass through opaque object or

obstacles.• It can’t cover a large area as that of radio waves.• There should be line of sight between sender and

receiver• Initial setup cost.

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CONCLUSION :• Faster • Smarter• Cheaper and also• Better

OR WE CAN SAY• Cleaner, Greener, Safer and Brighter future.

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REFERENCES :

• http://en.wikipedia.org/wiki/Li-Fi • seminarprojects.com/s/seminar-report-on-Li-

Fi • http://teleinfobd.blogspot.in/2012/01/what-

is-lifi.html • www.lificonsortium.org• the-gadgeteer.com/2011/08/LI-FI

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