CONTENTS:

1.Introduction

2.History

3.Construction of Li-Fi

4.Working of Li-Fi

5.Why only VLC

6.Advantages

7.Limitations and Challenges

8.Applications

9.Conclusion

INTRODUCTION

Li-Fi means light fidelity.

It can be used as light based Wi-Fi.

Instead of radio waves it uses visible rays for transmission.

Data can be transmitted through LED light.

HISTORYLi-Fi is a VLC [Visible Light

Communication] .

It is a technology developed by a team of

scientists including Dr Gordon Povey , Prof.

Harald Haas and Dr Mostafa Afghani at the

University of Edinburgh UK

.

The term Li-Fi was coined by Prof. Haas in

July 2011

Harald Hass, who is considered to be the

Father of Li-Fi says that the heart of Li-Fi

technology lies in the intensity and the potential

of the LEDs

HARALD HASS

Li-Fi consists of four primary sub-

assemblies:

Printed circuit board (PCB)

RF power amplifier (PA)

Bulb

Enclosure

Electrodes

Bulb Dielectric

material

The bulb is embedded in the

dielectric material

Two degradable electrodes are used.

Dielectric material serves two

purposes-waveguide, electric field

concentrator.

Plasma state-emits light of high

intensity.

The operational procedure is very

simple.

If the LED is ON digital 1 is

transmitted, if it is OFF digital 0 is

transmitted.

Lamp driver-codes data into

LED’s.

Photo detector encodes the data

Gamma rays can’t 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.

Radio waves

Infra-red Rays

Visible Rays

UV Rays

X-RaysGamma

Rays

High SPEEDMore SECURENO Electromagnetic Interference NOT HarmfulSaves POWERLow Cost

Limitations And Challenges

Light can’t pass through objects.Interferences from external light sources like sun

light, normal bulbs, and opaque materials in the path of transmission will cause interruption in the communication.

High installation cost of the VLC systems.A major challenge facing Li-Fi is how the receiving

device will transmit back to transmitter.

APPLICATIONS

Car Lights

oCars with LED based-Head

lights.

oCars communicate – prevent

accidents

Airports:

oWi-Fi will be slow.

oTo avoid these Li-Fi is used.

Visible Light is safer than RF

RF Restricted

Environment

Medical

• Operating rooms don’t allow Wi-Fi.

The possibilities are numerous and can be exploredfurther. If this technology can be put into practical use,every bulb can be used something like a Wi-Fi hotspotsto transmit wireless data.With its magic of light it can make our worldgreener , safer, cleaner and more over a brighter placeto live.

THANK YOU

Presented by

S.UMA SREEMUKHA