Under the guidance of

Asst. prof GIRISH KUMAR D

Presented by

KOTESHWAR RAO M

(3BR11IS017)

LI-FI is transmission of data through

illumination ,ie sending data through a LED

light bulb that varies in intensity faster

than human eye can follow

LI FI- LIGHT FIDEALITY

Li-Fi is now part of visible light communication (VLC).

It can be very easily explained as, if the LED is ON, you

are transmitting the data means you transmit a digital 1 ;

and if the LED is OFF you transmit a digital 0,or null, or

simply no data transfer happens.

As one can switch them on and off very frequently one

can transmit data easily because the LEDs intensity is

modulated so rapidly that human eye cannot notice, so the

output in form of light appears constant and hence

offering permanent connectivity.

Till now it was implemented through white LED bulbs only but

teams at the University of Oxford and the University of

Edinburgh are focusing on parallel data transmission by using

multiple LEDs or array of LEDs, where each LED transmits a

different stream of data.

Mixtures of red, blue, green LEDs are also used by some

groups to encode different data channels by altering the light

frequencies.

In simple terms we can consider it to be a light based Wi-Fi

which has achieved blistering high speed in the labs at Heinrich

Hertz institute in Berlin, Germany of around 500 megabytes

per second using a standard white-light LED.

So quiet obviously, modems would be replaced by transceiver

fitted LED lamps which can serve both in purposes of

lightening the room as well as transmitting the data.

Professor Harald Haas,

from the University of

Edinburgh in the UK, is

widely recognised as the

original founder of Li-Fi. He

coined the term Li-Fi and is

Chair of Mobile

Communications at the

University of Edinburgh and

co-founder of pureLiFi.

In October 2011, companies and industry groups formed the Li-Fi Consortium, to promote high-speed optical wireless systems and to overcome the limited amount of radio-based wireless spectrum available by exploiting a completely different part of the electromagnetic spectrum.A number of companies offer uni-directional VLC products which is not the same as Li-Fi.

VLC technology was exhibited in 2012 using Li-Fi. By August 2013, data rates of over 1.6 Gbit/s were demonstrated over a single color LED.In September 2013, a press release said that Li-Fi, or VLC systems in general, do not require line-of-sight conditions. In October 2013, it was reported Chinese manufacturers were working on Li-Fi development kits

In April 2014, the Russian company Stins Coman announced the development of a Li-Fi wireless local network called BeamCaster. Their current module transfers data at 1.25 gigabytes per second but foresee boosting speeds up to 5 GB/second in the near future.

Radio 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.

1.4 Million 5 Billion

Radio Waves

Infrared Rays

Visible Rays

Ultraviolet Rays

X- 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 bse

used with low power.

HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

LED ie Light emitting diode can be switched on and

off faster since operating speed of LED is less than

1 μs, than the human eye can detect, causing the

light source to be appear continuously. This

invisible on-off activity enables a kind of data

transmission using binary codes. Switching on and

LED is a logical ‘1’, switching it off is a logical

‘0’.It is possible to encode data in the light by

varying the rate at which LED’s flicker on and off

to give different strings of 1s and 0s. Modulation is

so fast that human eye doesn’t notice

LI FI CONSTRUCTION-The LI FI product consists of 4 primary sub-assemblies:

• Bulb

• RF power amplifier circuit (PA)

• Printed circuit board (PCB)

• Enclosure

3-The PCB controls the electrical inputs and outputs of the lamp and houses

the microcontroller used to manage different lamp functions.

2- An RF (radio-frequency) signal is generated by the solid-state PA and is

guided into an electric field about the bulb.

The high concentration of energy in the electric field vaporizes the

contents of the bulb to a plasma state at the bulb’s center; this controlled

pasma generates an intense source of light. All of these subassemblies are

contained in an aluminum enclosure.

Characteristics WI-FI LI-FI

Frequency 2.4GHz to 5GHz No frequency for light

Standard IEEE 802.11 IEEE 802.15

Range 100m Base on LED light

Primary application Wireless local area

networking

Wireless local area

networking

Data transfer rate 11Mbps >1Gbps

Power consumption Medium Low

Cost Medium High

Security Its medium secure Its high secure

Primary devices Notebook computers,

desktop

Mobile phones, office and

industrial

Advantages of Li-Fi Technologies

Long service life (10-15 years while usual bulbs last 1-2

years)

Energy Saving (8W LED bulb=60W ordinary Bulb)

Light emitting Diodes are a source of light (release large

amount of energy in the form of light)

Can be switched on/off at very high speed

Energy Efficiency

High speed data transfer

It’s main advantage is it’s bandwidth, It is 10,000 times

than the radio waves

Cost Benefits

The main drawback in LI-FI is power consumption.

Light signals not easily move just like as radio

signals they will follow certain path so it is also

draw back of LI-FI.

It consume more power rather that WI-FI

technology.

1. Health Technologies

2. Airlines

3. Power plants

4. Under sea working

5. Information delegation

6. Various other areas

7. Free from frequency bandwidth problem

8. Learning

9. Green Information technology

10. GPS usage

11. Increase Communication safety

12. Multi User Communication

13. Lightings points used as Hotspot

Possibilities for future utilization are abundant. Every light bulb can be converted into li-fi signal receptor to transfer data and we could proceed toward the cleaner, safer, greener and brighter future.

As we know that the airways are getting clogged day by day Li-fi can offer a genuine and very efficient alternative. Li-Fi is enabled by advanced digital transmission technologies. Optical cell networks based on Li-Fi are the link between future energy efficient illumination and cellular communications.

They can also harness unregulated, unused and vast amount of electromagnetic spectrum and can even enable ever smaller cells without the need for new infrastructure.

The issues of shortage of radio frequency can be tackled easily with only limitation being that it works in direct line of sight of light. There are no dead ends to technology and science. Now both light and radio waves can be used simultaneously to transfer data and signals

Further enhancements can be ma in this

method, like using an array of LEDs for

parallel data transmission or using mixture

of red, green and blue LEDs to alter the

light’s frequency with each frequency

encoding a different data channels.

Such advancements promise a theoretical

speed of 10 Gbps-meaning one can download

a full high definition film in just 30 seconds.

M. Afgani, H. Haas, H. Elgala, and D. Knipp, “Visible Light Communication using OFDM” in Proc. of the 2nd International Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities (TRIDENTCOM), Barcelona, Spain, March 1-3 2006, pp. 129-134.

http://www.electronicsforu.com/electronicsforu/circuitarchives/view_articl asp?sno=778&title%20=%20Li-Fi%3A+A+New+Paradigm+in+Wireless+Communication&b_type=new&I =12042

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

THANK YOU