Li fi

Light-FidelityLi-Fi

Seminar –

University Institute of Technology, BUComputer Science and EngineeringCode – CSE 752Md Quasim – T/2010/1066

LI-FI is transmission of data through illumination, sending data through a LED light bulb that varies in intensity faster than human eye can follow -German physicist, Prof. Harald Haas

INTRODUCTION OF LI – FI

Li-fi is a VLC (Visible Light Communication) technology developed by a team of scientist including Dr Gordon Povey, Prof. Harald Hass and Dr Mostafa Afgani at the university of Edinburg

Prof. Harald Hass

INTRODUCTION OF LI – FILight–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.Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over 500 megabytes per second using a standard white-light LED.It allows wireless communication without the use of radio waves, which can be dangerous in places like oil platforms, underwater and on planesLi-Fi can be thought of as a light-based Wi-Fi.

Li- Fi ENVIRONMENT

Li- Fi ENVIRONMENT

HOW IT WORKS

• 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.

• 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. Hence all that us required is some LEDS and a controller that code data into those LEDs.

HOW IT WORKS

• We have to just vary the rate at which the LED’s flicker depending upon the data we want to encode.

• A light sensitive device (photo detector) receives the signal and converts it back into original data.

WHY ONLY VLCRadio

Waves Infrared

RaysVisible 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 be used with low

power.HENCE WE LEFT WITH THE ONLY THE VISIBLE – LIGHT SPECTRUM.

ADVATAGES OF LI-FI (Visible Light Communication) OVER RADIO WAVES

IN TERMS OF CAPACITY

CAPACITY:

With the increasing number of mobile connections the availability of the spectrum is getting congested.

Radio waves form only a small fraction of the entire EM spectrum thus making the problem even worse.

CAPACITY:

Light is a readily available form of energy and it covers the major portion of the EM spectrum.

Visible light spectrum is 10000 times more compared to radio wave spectrum.

IN TERMS OF EFFICIENCY

EFFICIENCY:

For every unit of energy consumed the data transmitted is relatively less.

The data speeds in the current system can only reach up to a few hundreds of megabits per second.

EFFICIENCY:

The data transmission for a unit energy consumption is high in the case of light waves.

The data transmission can reach up to gigabits per second thus providing very rich data streaming.

IN TERMS OF AVAILABLITY

AVAILABILTY:

The availability of the radio waves is yet another major issue now a days.

These waves are not much available during the flight travel.

AVAILABILITY:

Light is readily available in every part of the world.

This makes it easy for people in airplanes to work on the internet.

IN TERMS OF SECURITY

SECURITY:

These radio waves can easily penetrate through the walls, thus letting anonymous users to use the network.

This can pose threat if the people with bad intentions start using it.

SECURITY:

Unlike radio waves light waves cannot penetrate through opaque objects thus providing plenty of network privacy.

No other person can share a network unless the owner has permitted them to use it.

COMPARISION OF LI-FI AND WI-FI

FUTURE APPLICATIONS• Li-Fi can be used in sensitive areas such as aircraft for data

transmission without causing interference. • It can be used in places where it is difficult to lay optical fibers like

operation theaters .• In traffic scenario, Li-Fi can be used to communicate with the LED

lights of cars and might alert drivers when other vehicles are too close so accident numbers can be decreased.

• It will improve conditions for those working in underwater oil rigs where radio waves can’t propagate.

• Thousands and millions of street lamps can be transferred to Li-Fi lamps to transfer data.

• It can be used in petroleum and chemical plants where other transmission or frequencies could be hazardous.

CHALLENGES FOR LI-FI

• Presence of Light is essential.• Li-Fi requires line of sight.• It is easily blocked by somebody simply walking in front of

LED source.• The grand vision: “LED lights with added microchips will let

us transmit thousands of data streams in parallel, enabling us to access the Internet on smartphones wherever there is a light source”.

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

• Issue of Wired world magazine, february 2012(Article Meet Li-Fi, the LED-based alternative to household Wi-Fi.)

• http://www.ted.com/talks/harald_haas_wireless_data_from_every_light_bulb.html

• http://www.lificonsortium.org/• Journal: International Journal of Innovative Research in

Computer and Communication Engineering ISSN/EISSN: 23209798 23209801

• Year:2013 Volume: 1 Issue: 2

• http://en.wikipedia.org/wiki/Li-Fi