technologyHigh speed bidirectional fully

networked wireless communication.

Project submitted by:

Vinay Kumar Gattu.

KNRR(ECE)

Introduction:

LI-FI is a technology that uses the light emitting diodes to transmit the data wirelessly.

LI-FI is fast and cheap optical version of Wi-Fi ,based on visible light communication(VLC).

VLC is a data communication medium, which uses the visible light between 400 THz (780 nm) and 800 THz (375 nm) as optical carrier for data transmission.

By this technology the led bulb having power of

one watt will distribute internet to four systems

at a time.

The led bulbs having microchips will transmit

internet with speed of 150mbps.

Diagrammatic representation of li-fi

LI-FI Environment:

WHO INVENTED IT ?

This technology was invented by German physicist

HARALD HAAS , from the University of Edinburgh.

He demonstrated it in the year 2012.

How LI-FI works:

The heart of this technology is a new generation high

brightness LED’S.

These LED’S varies in intensity (that is gets on and

off) so fast that a human eye cannot detect it.

If LED is ON , then we transmit logic 1, and if LED is

OFF , then we transmit logic 0.

A controller is connected at the back side of these

LED bulbs to code data to these LED’S.

LI-FI Equipment

LI-FI VS WI-FI

LI-FI has a High speed

data transfer rate over

1gbps.

Wi-Fi has a data

transfer rate of

maximum 54

mbps.

DATA TRANSFER

SPEED

• Why so much difference?

• LI-FI has an upper hand due to parallel data

transmission.

Part of EM spectrum they use

LI-FI

LI-FI uses the visible light portion of the EM spectrum.

WI-FI

Wi-Fi use the

radio wave portion

of EM spectrum

Issues with radio wave:

Capacity

• With advent of new technologies like 3G, 4G we are

running out of spectrum.

• This is because radio waves are now becoming

expensive.

Efficiency

There are 1.4 million cellular radio base stations.

Efficiency of each base station is just 5%.

Most of the energy is not used for transmission

but rather for cooling down the base station.

Security

• Radio waves can penetrate through walls

and hence can be intercepted.

• Any one with skills of hacking may misuse

it.

Availability

• We have to switch off mobiles in aircrafts.

• It is not advisable to use mobiles at petrol

bunks.

ALTERNATIVE OF RADIO WAVES

CAN IT BE INFRARED WAVES ?

Ir Waves Are Harmful For Our Eyes

Hence Used At Very Low Power

CAN IT BE UV RAYS?

• UV rays are harmful for our skin and cannot be used

for long duration.

CAN IT BE GAMMA RAYS ?

Gamma Rays Are Radioactive And Are

Dangerous.

CAN IT BE X-RAYS ? NO

SO WE ARE LEFT ONLY WITH VISIBLE

LIGHT SPECTRUM.

Advantages of li-fi which are limitations to

RW

CAPACITY

• 10000 Times More Spectrum Than Rw.

• Light Boxes Are Already Present, So

Infrastructure Is Available Already And

Installed.

EFFICIENCY

Highly Efficient Because Led Consumes

Less Energy.

AVAILABLITY

• Light Is Present Everywhere.

• Data is present where light is present.

SECURITY

• Light Waves Does not Penetrate

Through Walls.

• Hence they can’t be intercepted.

Advantages of LI-FI

• You Can Use Li-fi In Hospitals And Aircrafts Also.

• Cheaper Then Wi-Fi , Since Visible Light Spectrum Is

A Free Spectrum Band.

• No License Needed.

• Thousands And Millions Of Street Lamps Can Be

Converted To Li-fi Hotspots.

IS THIS A PROVEN TECHNOLOGY ?

Yes This Already Proven.

HARALD HAAS DEMONSTRATED HIS INVENTION

USING AN ORDINARY TABLE LAMP THAT

SUCCESSFULLY TRANSMITTED DATA AT SPEEDS

EXCEEDING 10mbps USING LIGHT WAVES FORM LED

LIGHT BULBS TO A COMPUTER LOCATED BELOW THE

LAMP. To Prove That The Light Was The Source Of

The Data Stream He Periodically Blocked The Beam

Of Light , Causing The Connection To Drop.