Presented By:

GAGANDEEP SINGH

04213202811

E.C.E.-1

GURU TEGH BAHADUR

INSTITUTE OF TECHNOLOGY

Seminar Presentation On:

Li-Fi Technology in Wireless

Communication

Introduction

History

Present Technology

Why Only VLC

Working Process Of Li-fi

Architecture Of Li-fi

Li-fi Environment

Li-fi Construction

Model Prototype Of Li-fi

Difference Between The Technologies

Applications

Advantages Of Li-fi

Limitations Of Li-fi

Conclusion

Refrences

Li-fi stands for light fidelity and li-fi is transmission technology of

data through illumination sending data through a led light bulb that

varies in intensity faster than human eye can follow

Li-fi is a technology that uses the light emitting diodes to transmit

the data wirelessly.

Led lights can be switched on and off at high speeds. This property

is the basics for li-fi. Led when on gives binary 1 and it off gives

binary 0.

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 to 800 thz (375 nm) as optical carrier for data

transmission.

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.

A German physicist Dr. Harald Haas, has

started working on transmission of data

using visible light back in 2004.

In the year 2011 he first introduced to the

world this new technology, LI FI in the

TED talk show.

He envisions a future where data for

laptops and other mobile devices is

transmitted through a light in a room.HARALD HASS

1.4 Million 5 Billion

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 .

1.4 Million base stations, 5 billion Mobile stations

600tb data every month

Major issues with radio waves are capacity , efficiency,

availibility and security.

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 bse used with low power.

We have already seen the short comings of radio waves.

HENCE WE LEFT WITH ONLY THE VISIBLE -LIGHT SPECTRUM.

Radio-Waves

Infra-Waves

VisibleRays

Ultra-Violet

X-raysGamma

Rays

Operational procedure is very simple, LED ie Light emitting diode can be

switched on and off faster since operating speed of LED is less than 1 μs, than

the human eye can detect, causing the light source to be appear continuously.

This invisible on-off activity enables a kind of data transmission using binary

codes. Switching on and LED is a logical ‘1’, switching it off is a logical ‘0’.It

is possible to encode data in the light by varying the rate at which LED’s

flicker on and off to give different strings of 1s and 0s. Modulation is so fast

that human eye doesn’t notice.

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.

Thus every light source will works as a hub

for data transmission.

The LiFi product consists of 4 primary sub-assemblies:

Bulb

RF Power Amplifier Circuit (PA)

Printed Circuit Board (PCB)

Enclosure

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

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

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

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

Can be used in the places where it is

difficult to lay the optical fiber like

hospitals. In operation theatre Li-Fi

can be used for modern medical

instruments.

Li-Fi can even wok underwater

were Wi-Fi fails completely, thereby

throwing open endless opportunities

for military/navigation operations.

In traffic signals Li-Fi can be used

which will communicate with the

LED lights of the cars and accident

numbers can be decreased.

Thousands and millions of

street lamps can be

transferred to Li-Fi lamps

to transfer data.

Whenever we travel through

airways we face the problem in

communication media ,because

the whole airways

communication are performed

on the basis of radio waves.In

aircraft Li-Fi can be used to

transmit data.

Visible Light is more safe

than RF, hence it can be

used in places where RF

can't be used such as

petrochemical plants

CAPACITY

10000times more spectrum than Radio waves.

Light box are already present.

We have the infrastructure available and alreadyinstalled.

EFFICIENCY

Data through illumination and thus data transmissioncomes for free.

Led light consumes less energy.

High efficient.

AVAILABILITY

Light is present everywhere.

Can be used in airplanes.

It can be underwater where radio waves cannot.

SECURITY

Light waves doesn’t penetrate through walls.

Can’t be intercepted and misused.

Data is present where there is light.

There should be line of sight between sender and receiver

Visible light cannot penetrate through solid objects

Interference with other electromagnetic waves makes the

transmitting data to distort

Light cannot approach the range and penetration of radio waves

High installation cost of the VLC systems

A major challenge facing Li-Fi is how the receiving device will

transmit back to transmitter.

Interferences from external light sources like sun light, normal

bulbs, and opaque materials in the path of transmission will cause

interruption in the communication.

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 Wi-Fi

hotspot to transmit wireless data and we will proceed

onwards the

Cleaner, Greener, Safer and Brighter future.

1. http://www.electronicsforu.com/electronicsfo

ru/circuitarchives/view_article.asp?sno=778&title%20=%2

0lifi%3a+a+new+paradigm+in+wireless+communication&

b_type=new&id=12042

2. lificonsortium.org

3. http://en.wikipedia.org/wiki/li-fi

4. ebookbrowse.com/an002-instrumentlighting-pdf-

d20428293

5. international journal of advances in computing &

communications, vol 1, 2013,page

no-12 www.ijacc.org

6. purevlc.com

GAGANDEEP SINGH

En. Roll. :04213202811

Serial No. : 039

(ECE-1)