Visible Light communication

By SAGINESH M K

APPLIED ELECTRONICSMPTC VADAKARA

Seminar on

Sustainable Energy-Efficient Wireless Application Using Light

OutlineIntroduction

Motivation

History

Technology and modulation

VLC Characteristics

VLC vs. RF Characteristics

Advantages & Disadvantages

Applications

Conclusion

Introduction

Lighting is a major source of electric energy consumption.

Visible light communication is a data communications medium using visible light between 400 THz-800THz.

General characteristics: visibilitySecurityHarmless for human bodyUnregulatedUsing in restricted areaEye safety

MotivationI. Now, researchers came to realize that

WLED devices could also be used for wireless purposes.

II. LEDs rends to be considerable cheaper than RF.

III.Optical wireless allows easy bandwidth reuse and improve security.

IV. It doesn’t generate RF contaminations.

V. Replacing RF device will reduce interference in RF band.

VI.RF radiation in hospital and airplane will be vanished .

VII.Large amount of energy can be saved.

VLC History1900s Current405 B.C. 1800s280 B.C. 1880~

FireFire

SunlightSunlight

LampLamp

LEDLED

Heliograph

Beacon

Fire

Pharos

Lighthouse

Ship-to-ship

Comm.

Photophone

By Bell

Traffic Light

/Signboard Light

800 B.C.

Burning KiteIn Battle

VLCVLC

Technology & Modulation

Data Light source

Modulation

(PPM/FSK)

DataDemodulatio

n(PPM/FSK)

PD or CCD

Why WLED ?

Brightness / Power ratio

Cost

/ B

rig

htn

ess r

ati

o

Incandescent Lamp

Halogen Lamp Fluorescent Lamp

LED

LED

LED

LED

2003

2005

2010

2015

50 100 1500

1

10

100

VLC CharacteristicD

ata

rate

(bps)

115K

4M

100M

480M

16M

50MUFIR

FIR

IR

VI

VLC

1 11

3

Distance (m)

2 6 20

50

UWB

802.11a

802.11b

Bluetooth

ZigBee

Transmitter/receiver of VLCVisible light LED

Fluorescent lamp

PIN photo diode

Avalanche photo diode

Image sensors

VLC vs. RF Characteristics

Property VLC RF

Visibility Yes No

Bandwidth Unlimited, 400nm~700nm

Regulatory, BW Limited

EMI No High

Hazard No Yes

Power Consumption

Relative low Medium

Coverage Distance

Short Medium

Advantages1.Transmit data by sockets of existing

light fixtures.

2.Alleviate a number of problems associated with the radio frequency (RF) communication systems.

3.consume far less energy .

4. Security.

5.Harmless for human body.

6.Eye safety.

Disadvantages1.Atmospheric absorption

2.Shadowing.

3.Beam dispersion

4.Interference from background light sources

Applications1.Under water communication system

2.Flow planning survey system for a store

Applications (contd)3.Inside airplane communication

4.Vehicle to vehicle messaging

5.Indoor broadcasting system.Applications

(contd)

Conclusion and outlookThere are many application that can

be realized using Visible Light Communication. Careful consideration will be needed to introduce it into a market.

ReferenceI. http://press-releases.techwhack.com/25210-irdaII. Hirohashi, Ikawa, Lin, “High-Speed Full-Duplex Multi-

access System for LED Based Wireless Communications Using Visible Light ”, International Symposium on Optical Engineering and Photonic Technology: OEPT 2009, July 2009, Orlando,

III. T. Komine and M. Nakagawa, “Fundamental analysis for visible-lightcommunication system using LED lights,” IEEE Trans. Consumer Electron vol. 50

IV. The Case for Vehicular Visible Light Communication (VLC): Architecture, Services and Experiments By Cen Bi Liu

V. Visible Light Communication Chung Ghiu Lee Chosun University South Korea

Questions ?

THANK YOU

Photophone

Heliograph

Image sensors

Image sensors