Li- Fi

(Light Fidelity)

- INTRODUCTION

- HOW LI-FI IS DIFFERENT ?

- HISTORY OF LI-FI

- LI-FI CONSTRUCTION

- WHY LI-FI COMES ?

- HOW LI-FI WORKS ?

- LI-FI VS WI-FI

- FEATURES

- ADVANTAGES

- DIADVANTAGES

- APPLICATIONS

- FUTURE SCOPE

- CONCLUSION

Contents

Introduction

Li-Fi means LIGHT FIDELITY

Li-Fi is fast and cheap optical versionof wi-Fi.

Li-Fi is a technology that uses theLIGHT EMITTING DIODES (LED) to

transmit the data wirelessly .

Li-Fi based on VISIBLE LIGHTCOMMUNICATION (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.

- Li-Fi technology is based on LEDs for the

transfer of data.

- The transfer of the data can be with the help of all kind

of light i.e., Light may be Invisible, Ultraviolet or

Visible part of spectrum.

- The speed of the internet is incredibly high and the

user everything in just a few minutes.

How Li-Fi Is Different ?

History of Li-FiThis technology was invented by German Physicist

HARALD HASS, from the university of Edinburgh, U.K.

- He demonstrated it in the year 2012.

- But, the technology was truly began during the 1990s in countries like

Germany, Korea & Japan.

- where they discovered LEDs could be retrofitted to send information

UNIVERSITY OF EDINBURGH :-

Li-Fi Construction

The Li-Fi product consists of three primary sub-assemblies:-

Emitter (including bulb) RF Driver. Power supply

Function of Bulb Assembly

At the heart of LIFI is the bulb sub-assemblywhere a sealed bulb is embedded in a

dielectric material.

The dielectric material serves two purposes:

1) waveguide

2) Electric field

Power amplifier (PA)assembly that uses an

LDMOS device.

Converts electrical energyinto RF power.

The PA is designed forruggedness and efficiency.

The RF driver also containscontrols circuit for digital

and analog lighting controls.

RF Drive

A Typical Li-Fi Scenario

Why Li-Fi comes ?

Capacity

Efficiency

Availability

Security

- Due to Issues regarding with Radio frequency Spectrum

- Electromagnetic spectrum

- These are -

Radio Spectrum Issues

Capacity

Radio waves.

Cost and Expensive.

Less Bandwidth compared to other

spectrums.

Insufficient spectrum for increasing

data.

Availability

Available within the range of

Base stations.

Limited availability.

Unavailable in aircrafts.

Efficiency

Millions of base stations consume

huge amount of energy for

1.) Transmitting the radio waves

2.) To cool the base station cabins

5% Efficiency

Security

Less secure(passes

through the walls)

Electromagnetic Spectrum

Radio Waves

Infrared Rays

Visible Rays

Ultraviolet Rays

X- Rays Gama Rays

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 be used with low power.

HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT

SPECTRUM.

WHAT USES CAN

REPLACE

RADIO WAVES FOR

WIRELESS

COMMUNICATION ?

THROUGH LI-FI- By the use of li-fi we can replace radio waves for wireless

communication

How Li-Fi Works ? Procedure is very simple, if the LED is on , then your device transmit a digit

1 & if it is off, then your device transmit a digit 0.

The LED can be switched on & off very quickly, which gives nice

opportunities for transmitting data.

Hence, all that required is some LEDS & a controller that code data into those

LEDS.

Comparison Between Li-Fi vs. Wi-Fi

Features of Li-Fi

CAPACITY- 10,000 Times more spectrum then RW.- Light boxes are already present, so infrastructure is available already and installed .

EFFICIENCY- Highly efficient because LED consume less energy.

AVAILABLITY- Light is present every where. - Data is present where light is present.

SECURITY- Light waves does not penetrate through walls. - Hence they can not be INTERCEPTED.

MAPS

Advantages of Li-Fi

It is impossible to achieve more than 10Gbps,

theoretically allowing a high-definition film

to be downloaded in 30 sec.

Mostly powered by LEDs so it is cost efficient

Transmission of data is fast and easy.

Disadvantages of Li-FiPresence of light is

essential

There should be line of sight

Works better with fluorescent

light and LEDs but very low

efficiency with bulbs.

Applications of Li-Fi

Street and

traffic

light

Under

water

scenarios

Airplane

scenarios

In RF

restricted

environment

Future Scope

This research report categories the global VLC technology market

based on component, application and geography.

Li-fi uses light emitting diodes (LEDs) which are rapidly gaining in

popularity for standards light bulbs and other domestic and commercial

purposes . They are expected to be ubiquitous in 20 years.

Still under research :-

What will be effect of interference from external light sources like sun

light and normal bulbs ?

What about the limited bandwidth of existing copper cable used for

electrical connection.

Future Scope

Where do the connections uplink, how serious are the

modifications needed to the power grid.

How will other devices React if you Inject a high frequency in to

Main ?

Conclusion

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 a Wi-Fi hotspots to transmit wireless data.

Thanks !

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