Embed Size (px)
Citation preview
Li-Fi (Light Fidelity)
Presented by:Naveen Nakka13765A1007
CONTENTS:• PRESENT WIRELESS COMMUNICATION
• ISSUES REGARDING RADIO SPECTRUM
• WHAT IS Li-Fi
• WORKING &BLOCK DIAGRAM
• TRANSMITTING & RECEIVING ELEMENTS
• COMPARISION BETWEEN Wi-Fi AND Li-Fi
• ADVANTAGES & DIS-ADVANTAGES
• APPLICATIONS
• CONCLUSION
PRESENT WIRELESS COMMUNICATION• Radio spectrum
• 1.4 Million base stations, 5 billion Mobile stations
• 600TB data every month
• Cost and Expensive.
• Less Bandwidth compared to other spectrums.
• Insufficient spectrum for increasing data.
• Millions of base stations consume huge amount of energy for
1.Transmitting the radio waves.
2.To cool the base station cabins
• Unavailable in aircrafts.
• Less secure(passes through the walls)
ISSUES REGARDING RADIO SPECTRUM
Is not used generally
Used for hospitals
Dangerous for human body
Which is not used so farSafe to useLarger bandwidth
Expensive, Limited BWLess Secure
Low power Applications
WHAT IS LI-FI....?Light Fidelity (li-fi). It is a simple, cost-effective way to connect to the Internet. It minimizes the need for long cables running from one end of the room to the other or from floor to floor. At the heart of this technology is a light-emitting diodes It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The flicker depending upon the data we want to encode. If the LED is on, you transmit a digital 1, if it’s off you transmit a 0. The LED bulb will hold a micro-chip that will do the job of processing the data.
LI-FI works with the help of Light basically LED’s and fluorescent lamps. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. So what you require at all are some LEDs and a controller that code data into those LEDs. Li-Fi technology is mainly based on LEDs for the transfer of data. The transfer of the data can be with the help of all kind of light i.e Light may be Invisible, Ultraviolet or Visible part of spectrum.
WORKING:
The basic principle here is modulation and de-modulation, the signal is modulated with the help of carrier signal here the carrier signal is light and the modulated signal is transferred through LED and it is detected by photo diodes here the modulated signal is de-modulated to get the modulating signal i.e. signal containing information. Internet from the server is fed to the LED through the lamp driver circuit the LED flickers according to the signal i.e. if it is on, you transmit a digital 1, if it’s off you transmit a 0. The flickering of LED is detected by photo sensors (photo diodes) are used. Therefore it is amplified to get the transferred signal.
BLOCK DIAGRAM
Data
Modulation
Light
SourceData Demodulation Photo Detector
TRANSMITTING ELEMENT
• Normally transmitting elements are LED.
• Fluorescent Lamp
RECEIVING ELEMENT(DETECTOR)• Photo Diode
• Image Sensors
Li-fi USB Key designed by for tablet
Li-Fi router for PC
Li-Fi Dongle for Smartphones.
LI-FI is a term of one used to describe visible light communication technology applied to high speed wireless communication. It acquired this name due to the similarity toWI-FI, only using light instead of radio.WI-FI is great for general wireless coverage within buildings, and li-fi is ideal for high density wireless data coverage in confined area and for relieving radio interference issues, so the two technologies can be considered complimentary.
COMPARISION BETWEEN Li-Fi & Wi-Fi
ADVANTAGES
• It is possible to achieve more than 10Gbps, theoretically
allowing a high-definition film to be downloaded in 30sec.
• Mostly powered by LEDs so cost is low.
• Transmission of data is fast and easy.
• Its main advantage is it’s Bandwidth is 10,000 times than the
radio waves.
DISADVANTAGES
• Presence of light is required.
• There should be line of sight.
• Works better with fluorescent light and LEDs but very low
efficiency with Bulbs.
• shadowing
APPLICATIONS
• Used for modern medical instruments.
• Used in petroleum or chemical plants
• where other transmission or frequencies could be hazardous..
• In Aircrafts.
IN RF RESTRICTED ENVIRONMENTS
HOSPITALS(IN FEW MEDICAL INSTRUMENTS)
IN AIRCRAFT CABINS
UNDER THE OCEAN
CONCLUSION:
The concept of Li-Fi is currently attracting because it may offer a genuine and efficient alternative to radio-based wireless. As a growing number of people and their devices access wireless internet, the air waves are becoming clogged, making it more and more difficult to get a reliable, high-speed signal. So Li-Fi has a bright future.
ANY QUERIES?????!!!!!!!!!!!
