LI-FI stands for “Light Fidelity”.

It is the transmission of data throughillumination ,sending data through a LightEmitting Diode which varies in intensity fasterthan human eye can follow to deliver highspeed data transmission.

History

1/25/20153

> The technology truly began during the1990’s in country like Germany, Korea,and Japan where they discovered LED’scould be retrofitted to send information.Harald Hass continues to wow the worldwith the potential to use light forcommunication.

Professor Harald Haas

INTRODUCTON

It is a Visible Light Communication(VLC) ,technologydeveloped by scientists including Dr.Gorden Povey ,Prof Harald Hass and Dr.Mostafa Afgani at UniversityOf Edinburgh.

These devices are normally used for illuminationby applying a constant current through the LED.

Li-fi is the term used for fast and cheap light basedWi-Fi but it uses light rather than radio waves.

Working of LI-FIHow LI-FI works?

• operational procedure is very simple, if the led is on, you

transmit a digital 1, if its off you transmit a digital 0. The

LEDs can be switched on and off very quickly, which gives

nice opportunities for transmitting data.

Working of LI-FI

Today’s Major Data Transmission Technique

Today’s majority of data technique uses Radio Spectrum .

Drawbacks of Radio Spectrum

But the fact that it is congested and the demand forwireless data double each year. Every thing , it seems wantto use wireless data but the capacity is drying up.

Availability :It is available within the range of Base stationsand unavailable in aircrafts.

Efficiency: Consumes huge amount of energy fortransmitting radio waves and to cool the base station cabins

Security: Less secure as it can also pass through walls.

How Li-Fi is different from others?Li-fi is based on LEDs for the transfer of data.

The transfer of data can be with the help of all kinds of light ,no matter the part of spectrum that they belong to.

The speed of the internet is incredibly high and one can download movies ,games ,etc. in just a few minutes.

It also removes the limitation to be in a region where Wi-Fi is only present.

Difference between Light Fidelity And Wireless Fidelity

Parameters Light Fidelity Wireless Fidelity

Medium Uses light as a carrier Uses radio spectrum

Spectrum range Visible light Spectrum Radio frequency spectrum

Speed for Data Transfer Future prospect predict speed>500 Mbps

Data transfer speed>150 Mbps

Cost Cheaper because free band doesnot need license and it uses only light

Expensive as it uses radio spectrum.

Operating frequency Hundreds of Tera Hz Usually 2.4 GHz.

Various Transmitting ElementsLamps

Light Emitting Diodes

Fluorescent Lamps

Study Lamps

Various Receiving Elements

Avalanche Photo Diode

Image Sensor

Potential Application of Li-fi

1.In House Communication :Giga shower

For giga speeds technologies ,the Li-fi consortium has defined GigaShower ,Giga MIMO and Giga Spot.

It provides bidirectional data services via several channels to multipleusers.

This is like watching TV channels or listening to different radio stationswhere no uplink channel is needed.

2.Traffic Lights

Traffic lights can communicate to each other and vehicles.

Cars ,Traffic lights and other vehicles too have LED-basedheadlights so data can be easily transmitted to each other.

3.In Aircraft cabins

This is one of the advantage of li-fi as it could be used in aircrafts because Wi-Fi can not be used there.

4.Hospitals

In hospitals li-fi can be used in those instruments which arecapable of light emitting and used for data transmission.

6.Street lamps as free access points

As there are million of street lamps deployed each of them can be used as free access points for internet and fast data transmission also.

Advantages of LI-FI

Higher Bandwidth (almost 10000 times more)

Availability

Efficiency

High Security

Easy to use

Fast data transfer

Harmless

Low cost

High capacity

Limitations in front of LI-FI

Light can not pass through objects.

A major challenge facing Li-fi is hoe the receiving device will transmit back to the transmitter.

High initial cost of VLC systems.

Interferences from external light sources like sun ,normal lights and opaque materials.

Further Enhancements

Further enhancements can be made in this like using an array of LEDs for parallel data transmission or mixtures of red , green and blue LEDs to alter the light’s frequency encoding a different channel.

Such development promise a theoretical speed of 10 Gbps-meaning one can download a full high-definition film in just few seconds.

Conclusion

The possibilities are numerous and can be explored further.

If this technology can be used to practicality ,every bulb can be used for something like a Wi-Fi hotspots to transmit wireless data.

References

1.www.en.Wikipedia.org/wiki/Li-Fi.

2.www.electronicsforu.com.

3.International Journal of advances in computing and communications .

4.www.ijacc.org