• Introduction

• What is Li-Fi??

• What is VLC??

• Why only VLC??

• Architecture of Li-Fi.

• How does Li-Fi works??

• Advantages, Disadvantage, Limitation.

• Comparison with other

• Applications.

In the olden days.

Wired networking

Satellites Communications.

Wireless Networking

• LI-FI (Light Fidelity) is transmission of data through

illumination-taking the fiber optics by sending data

through an LED light bulb.

• At the heart of this technology is a new generation

of high brightness LEDs.

• If the LED is on a digital 1 is transmitted, if the LED

is off then a digital 0 is transmitted. They can be

switched on and off in order to transmit data

continuously.

It is transmission of data through

illumination, i.e. sending data through a

LED light bulb that varies in intensity faster

than human eye can follow.

Li-Fi is a fast and cheap optical version of Wi-Fi,

The technology of which is based on Visible

light Communication(VLC).

VLC is a data communication medium, which

uses visible light between 400 THz(780 nm) and

800 THz (375 nm) as optical carrier for data

Transmission and illumination.

It uses fast pulses of light to transmit information

wirelessly.

Radio

Waves

Infrared

Rays

Visible

Rays

Ultraviolet

RaysX-Rays

Gama

Rays

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, due to eye safety regulation can only be used

with low power.

Hence we left with the only the VISIBLE- LIGHT SPECTRUM.

Conversion of data to light

Morse code is used

Fast speed

Microchip

Photo sensitive device

1. Cost is low as compare to other light device.

2. Visible light spectrum is 10000 times more

compared to radio wave spectrum.

3. Speed can reach up to thousands of GBps.

4. Parallel data transmission that helps to

increase speed.

5. Tariff rates cheap.

Presence of Light is essential.

Light can’t pass through objects.

Interferences from external light sources like sun

light, normal bulbs, and opaque materials in the

path of transmission will cause interruption in the

communication.

High installation cost of the VLC system

A major challenge facing Li-Fi is how the receiving

will transmit back to transmitter.

Technology Speed Data density

Wireless(Current)

Wi-Fi

IEEE802.11n

150Mbps *

Bluetooth 3Mbps *

IrDA 4Mbps ***

Wireless(Future)

WiGig 2Gbps **

Giga-IR 1Gbps ***

Li-Fi >1Gbps ****

Traffic lights

Safe Environments

On Ocean Beds

Public internet hotspots

Aircrafts