Light-Fidelity [Li-Fi}

Mv Dinesh

S. Sumanth

Sree Vidyanikethan engineering college

Tirupati.

A presentation by

Light-Fidelity

CONTENTS INTRODUCTION

ISSUES WITH RF COMMUNICATION

VISIBLE LIGHT COMMUNICATION

PRINCIPLE OF LI-FI TECHNOLOGY

WORKING OF Li-Fi

COMPARISON BETWEEN LI-FI AND WI-FI

APPLICATIONS

ADVANTAGES

LIMITATIONS

CLOSURE

REFERENCES

“It is a visible light communication system that uses light from light

emitting diodes (LEDs) as a medium to deliver wireless data to PC’s

and mobiles at high-speed in a similar manner as WI-FI”

Present Scenario

Radio Spectrum is congested but the demand for wireless data extending

very fastly. Every thing, it seems require wireless data but the capacity is

drying up.

1.4 Million 5 Billion

Issues With RF Communications

CONTD…CAPACITY:

• Radio waves.

• cost and expensive.

• Less Bandwidth compared to other spectrums.

• Insufficient Spectrum for increasing data.

EFFICIENCY:

• Millions of base stations consume huge energy for

1. Transmitting the radio waves.

2. To cool the base station cabins.

• 5% Efficiency

CONTD…

AVAILABILITY:• Available within the range of Base stations

• Limited availability

• Unavailable in air crafts

SECURITY:

• Less Secure (Data can Pass through walls)

WHY VLC ?

• Gama rays,X-rays,Ultraviolet rays are harmful for the human body.

• Infrared rays are also dangerous, due to eye safety regulation, andcan only be used with low power.

• Radio waves are expensive and they are less secure.

• Hence we are left with only the visible - light spectrum which isnot harmful for humans .

RADIO WAVES

Infrared Rays

Visible Rays

Ultraviolet Rays

X-rays Gama Rays

Principle of LI-FI technology Heart of Li-Fi technology is high brightness LED’s.

The LED bulb will hold a micro-chip that will do the job of processing the data.

The on/off activity of LEDs enables data transmission using binary codes.

Switching on an LED is a logical ‘1’; switching it off is a logical ‘0’.

A light sensitive device (photo detector) receives the signal

and converts it back into original data.

How Li-Fi Works ?

Li-Fi is implemented using white LED light bulbs at downlink transmitter.

By fast variations of the current, optical output can be made to vary at extremely

high speeds.

An overhead lamp fitted with an LED with signal processing microchip streams

data embedded in its beam at ultra high speeds to the photodiodes.

A receiver dongle then converts the tiny changes in amplitude into an electrical

signal, which is then converted back into a data stream & transmitted to a

computer or mobile device

DATA TRANSMISSION THROUGH LED’S

COMPARISON BETWEEN LI-FI AND WIFISl.No Parameters Light Fidelity Wireless Fidelity

1 Speed for data transfer Faster transfer speed (>1 Gbps) Data Transfer speed (150

Mbps)

2 Medium through which

data transfers occurs

Used Light as a carrier Used Radio spectrum

3 Spectrum Range Visible light spectrum has 10,000

time broad spectrum in

comparison to radio frequency

Radio frequency spectrum

range is less than visible

light spectrum.

4 Cost Cheaper than Wi-Fi because free

band doesn’t need license and it

use light.

Expensive in comparison to

Li-Fi because its uses radio

spectrum.

5 Network topology Point to point Point to point

6 Operating frequency Hundreds of Tera Hz (THz) 2.4 GHz

APPLICATIONS

• Visible Light is more safe than RF, hence it can be used in

places where RF can't be used such as petrochemical plants.

SAFE ENVIRONMENT

CONTD…AIRLINES:

• Airways communication are performed on the basis of radio waves.

Using communication causes interference between the two systems. To

overcomes this drawback on radio waves , li-fi is introduced.

• Li-Fi emits no electromagnetic interference and so does not interfere with

medical instruments, nor is it interfered with by MRI scanners.

HOSPITAL & HEALTHCARE:

UNDER WATER COMMUNICATION • Due to strong signal absorption in water, RF use is impractical. Acoustic

waves have extremely low bandwidth and disturb marine life. Li-Fi provides

a solution for short-range communications.

SMART LIGHTING• Street lamps can be used as a source of Li-Fi hotspots

ADVANTAGES OF LI-FI:Li-Fi removes the limitations that have been put on the user by the Wi-Fi.

a) CAPACITY:

Visible light has 10000 times wider bandwidth than radio waves . So, Li-Fi has

got better capacity and also the equipment's are already available.

b) EFFICIENCY:

Data transmission using Li-Fi is very cheap. LED lights consume less energy

and are highly efficient.

c) AVAILABILITY:

There are billions of light bulbs worldwide, they just need to be replaced with

LED’s for proper transmission of data.

d) SECURITY:

Light waves do not penetrate through walls. So, they can‘t be intercepted and misused.

LIMITATIONS• Interference from external light sources like sun light in the path of transmission

will cause interruption in the communication.

• The light waves cannot penetrate walls.

• This technology was demonstrated and it was detectable up to a distance of 10

meter.

• Installation cost of VLC systems are high

• It is easily blocked by somebody simply walking in front of LED source.

CLOSURE: As a growing number of people and their many devices access wireless internet,

making it more and more difficult to get a reliable, high-speed signal.

This may solve issues such as the shortage of radio-frequency bandwidth

Every light source in homes and offices could potentially be a “Li-Fi” hotspots

within 20 years.

When this technology becomes feasible like the Wi-Fi, then our life will be

awesome on earth.

“Forget wireless ,get faster internet through light bulbs..!”

REFERENCES

https://www.google.co.in

http://seminarprojects.com/Thread-report-on-li-fi-technology

http://www.technewspaper.net/best-five-benefits-of-li-fi-technology/

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

http://www.youtube.com/watch?v=gjqSgsKbagQ

http://www.purelifi.com/

http://lificenter.net/solutions/lifi-solutions

https://lificonsortium.org/