A POWER POINT PRESENTATION ON

LI-FI

AANM&VVRSR POLYTECHNIC GUDLAVALLERU

By

13030-EC-004

13030-EC-096

CONTENTS: WHAT IS LI-FI?

HISTORY

PRINCIPLE OF LI-FI

HOW DO IT WORK?

CONSTRUCTION

ARCHITECTURE

COMPARISION OVER OTHER WIRELESS

TECHNOLOGIES

LI-FI ENVIRONMENT.

MERITS AND DEMERITS.

APPLICATIONS

CONCLUSION

REFERENCES

WHAT IS LI-FI?

LI-FI is abbreviated

as light fideality.

Li-Fi can be thought

of as a light-based

Wi-Fi. That is, it uses

light instead of radio

waves to transmit

information.

HISTORY:

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.

Later in 2004 prof.Harald hass has demonstrated it

on TED global talk.

PRINCIPLE OF LI-FI:

The principle involved in li-fi is“data through

illumination”.That is by sending data through an LED

light bulb that varies in intensity faster than the human

eye can follow.

HOW DO IT WORK?

LI-FI is typically implemented using white LED bulbs at downlink transmitter.

operational procedure is very simple, if the led is on, you transmit a digital 1, if its off you transmit a 0.

The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data.

CONSTRUCTION:

An LED.

Power amplifier.

Printed circuit board.

Enclosure

A photo detector and regenarative circuit

are mounted on PCB and are enclosed

by enclosure to receive light from LED.

ARCHITECTURE OF LI-FI:

Comparision of LI-FI over WI-FI:

LI-FI WI-FI

Faster transfer speed

>1GBPS upto 10GBPS.

Used light as carrier.

Cheaper than Wi-Fi.

Does not require license

as it uses visible

spectrum.

Radiation free operation.

Uneffected by other rf

devices.

Data transfer speed is 150MBPS.

Used radio spectrum.

Expensive in comparision with li-fi.

Feces limitation of regulated bandwidth license.

Produces high radiation to surroundings.

Simply effected by a microwave oven.

LI-FI ENVIRONMENT:

MERITS:

High Security

Easy To Use

Fast Data Transfer

Reliable

Harmless ness

Low Cost

Wide range as every LED strret light may

be used as hot spot.

DEMERITS:

Connectivity while moving

Interferences from external light

sources like sun light, normal bulbs,

and opaque materials in the path of

transmission will cause interruption in

the communication.

APPLICATIONS:

STREET LAMPS[AS FREE ACCESS

POINTS]

CONCLUSION

:

REFERENCES:

[1].http://www.electronicsforu.com

[2]. http://en.wikipedia.org/wiki/Li-Fi

[3]. International Journal of advances in computing

& communications.

[4].www.ebookbrowse.com.