Li fi

LIGHT FIDELITY

LI-FI

BYUtkarsh singh vihan (ECE)

CONTENTS

• INTRODUCTION TO LIFI• HOW DOES IT WORKS?• COMPARISON WITH WI-FI• 4 ISSUES WITH RADIOWAVE• ALTERNATIVE FOR RADIO WAVE• APPLICATION OF LI-FI• IS IT A PROVEN TECHNOLOGY?

INTRODUCTION TO LI-FI• LI-FI IS A TECHNOLOGY THAT USES THE LIGHT

EMITTING DIODES TO TRANSMIT THE DATA WIRELESSLY.

• LI-FI IS FAST AND CHEAP OPTICAL VERSION OF WI-FI ,BASED ON VISIBLE LIGHT COMMUNICATION(VLC).

• VLC IS A DATA COMMUNICATION MEDIUM,WHICH USES THE VISIBLE LIGHT BETWEEN 400 THz (780 nm) and 800 THz (375 nm) AS OPTICAL CARRIER FOR DATA TRANSMISSION

A LI-FI ENVIRONMENT

WHO INVENTED IT ?

• THIS TECHNOLOGY WAS INVENTED BY GERMAN PHYSICIST HARALD HAAS , FROM THE UNIVERSITY OF EDINBURGH ,U.K .

• HE DEMONSTRATED IT IN THE YEAR2012.

HOW DOES LI-FI WORKS?

• THE HEART OF THIS TECHNOLOGY IS A NEW GENERATION HIGH BRIGHTNESS LED’S.

• THESE LED’S VARIES IN INTENSITY (THAT IS GETS ON AND OFF) SO FAST THAT A HUMAN EYE CANNOT DETECT IT.

• IF LED IS ON , THEN WE TRANSMIT A DIGITAL SIGNAL 1,AND IF THE LED IS OFF , THEN WE TRANSMIT A DIGITAL SIGNAL 0.

• A CONTROLLER IS CONNECTED AT THE BACK SIDE OF THESE LED BULBS TO CODE DATA TO THESE LED’S.

LIFI VS WIFI

DATA TRANSFER SPEED

• Li-Fi has a High speed data transfer rate over 1Gbps.

• Wi-Fi has a data transfer rate of maximum 54Mbps

•WHY SO MUCH DIFFERENCE?

• LI-FI HAS AN UPPERHAND DUE TO PARALLEL DATA TRANSMISSION.

LI-FI VS WIFI (CONTD…)PART OF EM SPECTRUM THEY USE

• LI-FI USES THE VISBLE LIGHT PORTION OF THE EM SPECTRUM

• WIFI USE THE RADIOWAVE

PORTION OF THE EM SPECTRUM

ISSUES WITH RADIO WAVE

CAPACITY

• WITH THE ADVENT OF NEW TECHNOLOGIES LIKE 3G ,4G WE ARE RUNNING OUT OF SPECTRUM.

• THAT’S WHY RADIO WAVES ARE NOW BECOMING EXPENSIVE.

EFFICIENCY

• THERE ARE 1.4 MILLIONS CELLULAR RADIO BASE STATIONS .

• EFFICIECY OF EACH BASE STATION IS JUST 5%.• MOST OF THE ENERGY IS NOT USED FOR

TRANSMISSION BUT RATHER FOR COOLING DOWN THE BASE STATION.

SECURITY• RADIO WAVES CAN PENETRATE THROUGH

WALLS AND HENCE CAN BE INTERCEPTED.• ANYONE WITH KNOWLEDGE AND BAD

INTENTION CAN MISUSE IT.AVALILABLITY• WE HAVE TO SWITCH OFF MOBILES IN

AIRCRAFTS.• IT IS ALSO NOT ADVISABLE TO USE MOBILES

AT PETROL PUMPS.

ALTERNATIVE OF RADIO WAVES

CAN IT BE INFRARED WAVES ? NO

IR WAVES ARE HARMFUL FOR OUR EYES HENCE USED TA VERY LOW POWER

CAN IT BE UV RAYS? NO• UV RAYS ARE HARMFUL FOR OUR SKIN AND

CANNOT BE USED FOR LONG DURATION. CAN IT BE GAMMA RAYS ? NO• GAMMA RAYS ARE RADIOACTIVE AND ARE

DANGEROUS. CAN IT BE X-RAY S ? NO

SO WE ARE LEFT ONLY WITH VISIBLE LIGHT SPECTRUM.

OVERCOMING THE FOUR ISSUES WITH RW IN LI-FI

1. CAPACITY• 10000 TIMES MORE SPECTRUM THAN RW. LIGHT BOXES ARE ALREADY PRESENT, SO

INFRASTRUCTURE IS AVAILABLE ALREADY AND INSTALLED.

2. EFFICIENCY• HIGHLY EFFICIENT BECAUSE LED CONSUMES

LESS ENERGY.

3. AVAILABLITY• LIGHT IS PRESENT EVERYWHERE.• DATA IS PRESENT WHERE LIGHT IS PRESENT.

4. SECURITY• LIGHT WAVES DOESNOT PENETRATE

THROUGH WALLS.• HENCE THEY CAN’T BE INTERCEPTED.

ADVANTAGES OF LI-FI• YOU CAN USE LI-FI IN HOSPITALS AND

AIRCRFTS ALSO.• CHEAPER THEN WIFI , SINCE VISIBLE LIGHT

SPECTRUM IS A FREE SPECTRUM BAND.• NO LICENSE NEEDED.• THOUSANDS AND MILLIONS OF STREET

LAMPS CAN BE COVERTED TO LI-FI SPOTS.

IS THIS A PROVEN TECHNOLOGY ?

• YES THIS ALREADY PROVEN.• HARALD HAAS DEMONSTRATED HIS INVENTION

USING AN ORDINARY TABLE LAMP THAT SUCCESSFULLY TRANSMITTED DATA AT SPEEDS EXCEEDING 10Mbps USING LIGHT WAVES FORM LED LIGHT BULBS TO A COMPUTER LOCATED BELOW THE LAMP.TO PROVE THAT THE LIGHT WAS THE SOURCE OF THE DATA STREAM HE PERIODICALLY BLOCKED THE BEAM OF LIGHT , CAUSING THE CONNECTION TO DROP.

THANK YOU