1. By, U.Naga Pradeep RRS college of engg and tech 2. Li Fi is transmission of data through illumination by taking the fiber out of fiber optics by sending data through a LED light bulb that varies in intensity faster than the human eye can follow. Li-Fi is the term some have used to label the fast and cheap wireless-communication system, which is the optical version of Wi-Fi. 3. Harald Haas from the University of Edinburgh,UK Harald Haas continues to wow the world with the potential to use LED light for communication 4. The technology truly began during the 1990's in countries like Germany, Korea, and Japan where they discovered LED's could be retrofitted to send information. 5. TED Global talk on VLC. Harald Haas explained, Very simple, if the LED is on, you transmit a digital , if its off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting Radio waves are replaced by light waves in a new method of data transmission which is being called Li-Fi. Light-emitting diodes can be switched on and off faster than the human eye can detect, causing the light source to appear to be on continuously. g data. 6. Light-emitting diodes (commonly referred to as LEDs and found in traffic and street lights, car brake lights, remote control units and countless other applications) can be switched on and off faster than the human eye can detect, causing the light source to appear to be on continuously, even though it is in fact 'flickering'. This invisible on-off activity enables a kind of data transmission using binary codes: switching on an LED is a logical '1', switching it off is a logical '0'. 7. Li Fi (Light Fidelity) 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. 8. Over 1.8 million Over 340 million continues 9. Capacity Availability Efficiency Security 10. The main components of this communication system are: 1) a high brightness LED, 2) a silicon photodiode which shows good response to visible wavelength region serving as the receiving element 11. The LI FI product consists of 4 primary sub- assemblies: Bulb RF power amplifier circuit (PA) Printed circuit board (PCB) Enclosure receiver dongle 12. On one end all the data on the internet will be streamed to a lamp driver when the led is turned on the microchip converts the digital data in form of light A light sensitive device (photo detector) receives the signal and converts it back into original data. This method of using rapid pulses of light to transmit information wirelessly is technically referred as Visible Light Communication 13. Further enhancements can be made in this method, like using an array of LEDs for parallel data transmission, or using mixtures of red, green and blue LEDs to alter the lights frequency with each frequency encoding a different data channel. Such advancements promise a theoretical speed of 10 Gbps meaning one can download a full high-definition film in just 30 seconds 14. LI-FI is a term of one used to describe visible light communication technology applied to high speed wireless communication. Wi-Fi is a wireless networking technology that allows computers and other devices to communicate over a wireless signal. 15. Some of the applications of Li-Fi are given below: Airways Green information technology Free from frequency bandwidth problem Increase communication safety Multi user communication Lightings points used as hotspot Smarter power plants Under sea Awesomeness 16. Li-Fi could offers safe, abundant connectivity for all various of sensitive locations. Can be used underwater without radio interference because salt conducts electricity 17. It is impossible to achieve more than 10Gbps, theoretically allowing a high- definition film to be downloaded in 30 sec. Mostly powered by LEDs so it is cost efficient Transmission of data is fast and easy. 18. Presence of light is essential There should be line of sight Works better with fluorescent light and LEDs but very low efficiency with bulbs 19. Li-Fi is certainly not useless, but it has certain inherent limits for the technology. Li-Fi may not be able to replace conventional radios altogether, but it could turbo charge the development of wireless television and make it easier to throw a wireless signal across an entire house. At present, finding the ideal position for a wireless router is something of a divine art.