LIFI

(LIGHT FEDILITY)

CONTENTS

• INTRODUCTION• WORKING• COMPARISION• ADVANTAGES• DISADVANTAGES• APPLICATIONS

INTRODUCTION

WHAT IS LI-FI?• LI-FI is transmission of data through illumination ,sending data

through a LED light bulb.• LI-FI comes under VLC(VISIBLE LIGHT COMMUNICATION)

INTRODUCTION

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. Harald Haas continues to wow the world with the potential to use light for communication.

WORKINGHow LI-FI works?• operational procedure is very simple, if the led is on, you

transmit a digital 1, if its off you transmit a digital 0. The LEDs can be switched on and off very quickly, which gives

nice opportunities for transmitting data.

WORKING PRINCIPLE

LAN Server

Router

Display Signal processing

Photo detector

Led Lamp

TRANSMISSION ELEMENT

• Signals from the data input is modulated to intensity of light.

• Transmission side simply contains an led lamp which transmits the modulated light signals.

• This led lamp contains a series of LED’s which proto fits according to the input given.

RECEIVING ELEMENT

• Receiving elements are “AVALANCHE PHOTO DIODE” .• Avalanche photo diode is responsible for converting the light

signal into electrical signal and further the procedure is carried out by image sensor.

ILLUSTRATION

COMPARISIONWHY VLC??

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 rays, due to eye safety regulation, can only

be used with low power.

ISSUES REGARDING RADIO SPECTRUM

Cont…

CAPACITY• Radio waves• Cost and expensive• Less bandwidth compared to other spectrums• Insufficient spectrum for increasing data

 

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

 

Cont…

AVAILABILITY• Availability within the range of base stations• Limited availability• Unavailability in aircrafts

 

SECURITY• Less secure(passes through the walls

PRESENT SCENARIO

1.4 million 5million

• Radio Spectrum is congested but the demand for wire-less data double each year .Everything, it seems wants to use wireless data but the capacity is drying up

DIFFERENCE B/W TECHNOLOGIES

TECHNOLOGY SPEED

Fire wire 800 Mbps

USB 3.0 5 Gbps

Thunder bolt 20 Gbps

Wi-Fi 150 Mbps

Bluetooth 3 Mbps

IrDA 4 Mbps

Wi-Gig 2 Gbps

Giga-IR 1Gbps

Li-Fi >10 Gbps

APPLICATIONS

• Used in traffic lights which can communicate with cars to avoid accidents.

• Used in airlines: Generally in airlines mobile phones can’t be used as they can effect the radars which are main way of communication.

• Used in power plants for faster data exchange.• Underwater communications. (rare)

ADVANTAGES

• Availability • Efficiency • High security• Easy to use• Fast data transfer• Harmless• Low-cost

DISADVANTAGE

• However, everything comes with a disadvantage. The major disadvantage here is the fact that these signals cannot penetrate walls. So if you want to move from one room to another, you will need to have a wired bulb present in that room as well!

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 hotspot to transmit wireless data and we will proceed toward the cleaner, greener, safer and brighter future.

REFERENCES

• http://timesofindia.indiatimes.com/home/science/Now-just-light-a-bulb-to-switch-on-your-broadband/articleshow/9713554.cms

• http://oledcomm.com/lifi.html• http://en.wikipedia.org/wiki/Li-Fi• http://slideshare.com/li-fitech.html