Li FI Technology ppt slides

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Published Date:09-03-2017
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LI-FI TECHNOLOGYINTRODUCTION • Light Fidelity (Li-Fi) is a bidirectional, high-speed and fully networked wireless communication technology similar to Wi-Fi. • LI-FI is a technology that uses the light emitting diodes to transmit the data wirelessly. • LI-FI is fast and cheap practical 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 transmissionHistory 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. Harald Haas continues to wow the world with the potential to use light for communication. HE DEMONSTRATED IT IN THE YEAR 2012. PROFESSOR,UNIVERSITY OF EDINBURGH, UKLi-fi environmentPRESENT SCENARIO “ Mobile phones transmit 600 TB data every month. Wireless communication has become an utility like electricity and water.RADIO SPECTRUM ISSUES ◎ CAPACITY  Radiowaves  Cost and Expensive  Less Bandwidth compared to other spectrums  Insufficient spectrum for increasing data ◎ EFFICIENCY  Millions of base stations consume huge amount of energy for 1.Transmitting the radio waves 2.To cool the base station cabins  5% EfficiencyRADIO SPECTRUM ISSUES ◎ AVAILABILITY  Available within the range of Base stations  Limited availability  Unavailable in aircrafts ◎ SECURITY  Less secure(passes through the walls)  Anyone with knowledge and bad intention can misuse itAlternative of radio wavesWHY ONLY VLC ?? Gama Radio Infrared Visible Ultraviolet X- Rays Rays Waves Rays Rays 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.Working Process  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. We have to just vary the rate at which the LED’s .  Flicker depending upon the data we want to encode .  Thus every light source will works as a hub for data transmission .LI-FI CONSTRUCTION The LI FI product consists of 4 primary sub-assemblies: • Bulb • RF power amplifier circuit (PA) • Printed circuit board (PCB) • Enclosure 1. 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 plasma generates an intense source of light. 2. The PCB controls the electrical inputs and outputs of the lamp and houses the microcontroller used to manage different lamp functions. 3. An RF (radio-frequency) signal is generated by the solid-state PA and is guided into an electric field about the bulb. 4. All of these subassemblies are contained in an aluminum enclosureHow It Works ?? 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.  On the other hand, this light is detected by photo sensitive devices.  Next this device is amplified and processed and then fed to the device.APPLICATION AREAS ◎TRAFFIC LIGHTS Traffic lights can communicate to the car and with each other. Cars have LED-based headlights, LED-based cack lights, and cars can communicate with each other and prevent accidents in by exchanging information.APPLICATION AREAS ◎HOSPITALS In operation theatre, Li-Fi can be used for modern medical instrumentsAPPLICATION AREAS ◎AIRLINES Whenever we travel through airways we face the problem in communication media , because the whole airways communication are performed on the basis of radio waves. To overcome this drawback on radiowaves , li-fi is introduced.APPLICATION AREAS ◎INTRINSICALLY SAFE ENVIRONMENT It can be used in petroleum or chemical plants where other transmission or frequencies could be hazardous.APPLICATION AREAS ◎ON OCEAN BED Li-Fi can even work underwater were Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.APPLICATION AREAS ◎STREET LAMPS There are millions of street lamps deployed around the world. Each of these street lamps could be a free access point.