LIGHT FIDELITY (Li-Fi)

TECHNOLOGY

PRESENTED BY AMBIKA R (1MV10CS008)

BHAGYASHREE (1MV10CS023)

CHAITRA CN (1MV10CS030)

SUPRIYA (1MV11CS417)

CONTENTS

HistoryIntroductionWhy VLC?Present ScenarioWorking processAdvantagesApplicationsIs this a proven technology?ConclusionReferences

History

Light–Fidelity (Li-Fi) technology came into existence in 2011. The term was first used by Harald Haas in his TED Global talk on Visible

Light Communication. In October 2011 a number of companies and industry groups formed the Li-

Fi.consortium, to promote high-speed optical wireless systems.

..

Introduction

Li-Fi is transmission of data through illumination by taking the fiber out of fiber optics by sending data through a LED light bulb that varies in intensity faster than the human eye can follow.

Li-Fi is fast and cheap optical version of wi - fi based on visible light communication(VLC).

At the heart of this technology is the high brightness light-emitting diodes.

Introduction(contd…)

The on-off activity of LEDs enables a kind of data transmission using binary codes. Switching on an LED is a logical ‘1’;switching it off is a logical ‘0’.

It allows wireless communication without the use of radio waves, which can be dangerous in places like oil platforms, underwater and on planes Li-Fi can be thought of as a light-based Wi-Fi.

Why VLC?

Present ScenarioRadio Spectrum is congested but the demand for wireless

data double each year .Every thing, it seems want to use wireless data but the capacity. is drying up.

5 Billion1.4 Million Base Stations

Li-Fi Construction

The Li-Fi product consists of 5 primary sub-assemblies: Bulb RF Power Amplifier Circuit (PA) Optics Printed Circuit Board (PCB) Enclosure

Li-fi Environment

Working Process 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.

Flicker depending upon the data we want to encode . Thus every light source will works as a hub for data transmission .

Visible Light Communication

Methods for Visible light CommunicationDevices used for visible Communication.Communication using images Sensors.

Devices used for VLC

Transmitter Device Receiver Device

Transmitter Device

The transmission side contains an LED Lamp which transmits the modulated light signals.

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

Receiver device

The receiving elements arePIN Photo Diode Image Sensor

PIN Photo Diode

A PIN diode is a diode with a wide, lightly doped 'near' intrinsic semiconductor region between a p-type semiconductor and an n-type semiconductor region.

The wide intrinsic region makes the PIN diode an inferior rectifier. A PIN diode operates under what is known as high-level injection.

Image sensor

An image sensor is a device that converts an optical image into an electronic signal.

It is used mostly in digital cameras, camera modules and other imaging devices.

Communication using Image Sensors

Comparision between Li-Fi and Wi-Fi

LIGHT BASED Wi-Fi. Li-Fi would use transceiver-fitted LED lamps . Wi-Fi is great for general wireless coverage within buildings, and li-fi is

ideal for high density wireless data coverage in confined area. So the two technologies can be considered complimentary.

Advantages

Capacity 10000times more spectrum than Radio waves. Light box are already present. We have the infrastructure available and already

installed.

Efficiency Data through illumination and thus data transmission

comes for free. Led light consumes less energy. High efficient.

Availability Light is present everywhere. Can be used in airplanes. It can be underwater where radio waves cannot.

Security Light waves doesn’t penetrate through walls. Can’t be intercepted and misused. Data is present where there is light.

Application AreasLi Fi technology is still in its infancy .However some areas where it seems perfectly applicable are:-POTENTIAL APPLICATION OF LI-FI

1 . Traffic Lights :

Traffic lights can communicate to the car and with each other. Cars have LED-based headlights, LED-based cack lights, and cars can communicate with each other and prevent accidents in by exchanging information.

2.Hospitals(In Few Medical Equipments) :

3.Airlines :Whenever we travel through airways we face the problem in communication media ,because the whole airways communication are performed on the basis of radio waves. To overcome this drawback on radio ways , li-fi is introduced.

4. On Ocean Beds :

Li-Fi can even wok underwater were Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.

5. Street Lamps (As free Access Points) :

There are millions of street lamps deployed around the world.

Each of these street lamps could be a free access point.

Is it a proven technology???? Yes, this is already proven.

Dr. Harald Hass demonstrated his invention using an ordinary

table lamp that successfully transmitted data at speeds

exceeding 10Mbps .

To prove that the light bulb was the source of data stream, he

periodically blocked the beam of light, causing the connection

to drop.

Future scope Education system. Extends our life span. Reduction in accident number. Replacement for other technologies.

Challenges for LI-FI Light can't pass through objects .

Interferences from external light sources like sun light.

Li- Fi requires line of sight.

A major challenge facing Li-Fi is how the receiving device will transmit back to transmitter.

Conclusion The possibilities are numerous and can be explored further. Cheap and fast. If this technology can be put into practical use every bulb can be

used something like a Wi-Fi hotspots to transmit wireless data. As a growing number of people and their many devices access

wireless internet, the airwaves are becoming increasingly clogged, making it more and more difficult to get a reliable, high-speed signal.

Li-Fi Technology which is for a cleaner, greener and brighter future of planet.

References  http://en.wikipedia.org/wiki/Li-Fi

http://teleinfobd.blogspot.in/2012/01/what-is-lifi.html

www.lificonsortium.org/

Will Li-Fi be the new Wi-Fi?, New Scientist, by Jamie Condliffe, dated 28

July 2011

http://www.digplanet.com/wiki/Li-Fi

“Visible-light communication: Tripping the light fantastic: A fast and cheap

optical version of Wi-Fi iscoming”, Economist, dated 28 Jan 2012

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