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Li-Fi concepts and its applications


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Presented by P.GEETHA Ph.D scholar-NIT- Trichy P.GEETHA Associate Professor


OVERVIEW Introduction Comparison Evolution of Li Fi Working Components Construction Applications Advantages Limitations Conclusion


Introduction Li- Fi is transmission of data through illumination, sending data through a LED light bulb. Li- Fi , or light fidelity, is 5G visible light communication systems using light from light-emitting diodes (LEDs) as a medium to deliver networked, mobile, high-speed communication in a similar manner as Wi-Fi and Optical fiber. Li- Fi could lead to the Internet of Things.


LIGHT FIDELITY Optical version(Light based) of Wi-Fi Light is used instead of radio-waves to transmit information Transceiver fitted LED lamps acts like Wi-Fi modems LED lamps can light a room as well as transmit-receive information Provides illumination as well as data communication


NEED FOR L i -F i Radio spectrum is congested, but the demand for wireless data doubles each year Issues regarding radio spectrum, such as capacity, availability, efficiency, security are solved using LiFi . Speed of data transmission can be increased.

Comparison between Various Technologies :

Comparison between Various Technologies Fire wire 800 Mbps USB 3.0 5 Gbps Thunderbolt 20 Gbps Wired Wireless(Current) Wireless(Future) Li-Fi 10 Gbps Giga-IR 1 Gbps Wi-Gig 2Gbps Wi-Fi 150 Mbps Bluetooth 3 Gbps IrDA 4 Gbps


OVERCOMING W i F i ISSUES CAPACITY Spectrum is 10,000 times greater than that of radio frequency EFFICIENCY Highly efficient since LED consumes less energy AVAILABILITY Light waves available everywhere . SECURITY Cannot penetrate through walls. Hence data cannot be intercepted.

Visible Light Communication:

V isible Light Communication Li- Fi can be the technology for the future where data for laptops, smart phones, and tablets will be transmitted through the light in a room. Security would not be an issue because if you can‘t see the light, you can‘t access the data. As a result, it can be used in high security military areas where RF communication is prone to eavesdropping.


VISIBLE LIGHT COMMUNICATION In electromagnetic spectrum, gamma, UV rays are dangerous for human body. IR rays, due to eye safety regulation, can only be used with low power.

Development Team:

Development Team Li- Fi is a Visible Light Communication (VLC), technology developed by a team of scientists including Dr. Gordon Povey , Prof. Harald Haas and Dr. Mostafa Afgani at the University of Edinburgh. Dr. Gordon Povey Prof. Harald Haas Dr. Mostafa Afgani


LIFE OF LiFi 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. Professor Harald Haas Original founder of Li- Fi . Chairman of Mobile Communications at the  University of Edinburgh. Co-founder of pureLiFi . Prof. Harald Haas University of Edinburgh,U.K

Life of Li-Fi(Contd…):

Life of Li- Fi ( Contd …) In October 2011, Li- Fi Consortium- promote high-speed optical wireless systems . VLC technology was exhibited in 2012 using Li- Fi . By August 2013, data rates of over 1.6 Gbit /s were demonstrated over a single color LED. In September 2013, a press release said that Li- Fi , or VLC systems in general, do not require line-of-sight conditions. In October 2013, it was reported Chinese manufacturers were working on Li- Fi development kits. Philips lighting company has developed a VLC system for shoppers at stores. They have to download an app on their smart phone and then their smart phone works with the LEDs in the store.


HOW IT WORKS? Operational procedure is very simple. Normal light power is replaced by LED light power. The LED bulb will hold a micro-chip that will do the job of processing the data. If LED is ON, digital data ‘1’ is transmitted & if LED is OFF, digital data ‘0’ is transmitted. LEDs varies in intensity so fast that a human eye cannot detect it. A controller connected at the back side of these LEDs is used to code data. Also called as 5G optical communication. Parallel data transmission




VLC-SET UP All the data from Internet is streamed into lamp driver. Data from internet is used to modulate the intensity of LED light source. Thus by fast and subtle variations of current, optical output can be made to vary at extremely high speed The photo detector picks up the signal The receiver dongle then converts the tiny changes in amplitude into a data stream.


MAIN COMPONENTS A high brightness white LED , Which act as a communication source. A photodiode which shows good response to visible wavelength region serving as the receiving element.


Li Fi CONSTRUCTION The LI FI product consists of 4 primary sub-assemblies: • Bulb • RF power amplifier circuit (PA) • Printed circuit board (PCB) • Enclosure


HOW IT IS DIFFERENT????? Li- Fi technology is based on LEDs for the transfer of data. The transfer of the data can be with the help of all kinds of light. Also, the speed of the internet is incredibly high and we can download movies, games, music etc in just a few minutes with the help of this technology.



L i -F i NETWORKS Li- Fi connector and router are the main components for a network Room connector: Optical signals cannot penetrate through walls, in order to provide an optical WLAN, rooms need to be connected with each other Li- Fi room connector is a replicator, which sends the data stream from one side of the wall to the other side via an optical fiber. For smaller rooms, connector act as the only Li- Fi hotspot in the room


LI-FI ROUTER Serves as a connector to external link like DSL. Covers a radius of about 20 meters The transmission speed is 100 Mbps. Suitable for small office or home use


APPLICATIONS LiFi can be used in sensitive areas such as aircrafts for data transmission without causing interference Places where it is difficult to lay optical fibers like operation theaters Traffic scenarios, thereby reducing accidents Underwater applications where radio waves cannot propagate. Industries like petrochemical plants, nuclear power plants , petrol pumps etc


TRAFFIC SCENARIO In traffic scenario, LiFi can be used to communicate with the LED lights of cars Cars can have LED-based headlights, backlights and can communicate with each other. This might prevent accidents, by exchanging information, when the vehicles are too close Using LiFi , Street lights can be used to send information about the road condition to the car.


LECTURE / SEMINAR HALLS Downloading notes from blogs of teachers. Interactive classroom with interconnected devices. Sharing views & queries with the entire class

On Ocean Beds : :

On Ocean Beds : Li- Fi can even wok underwater were Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.


INDUSTRIES Used in RF restricted environments like chemical industries, nuclear power plants, petrol pumps




HOME AND SMALL OFFICES In home and small offices, Li- Fi can be used to communicate with devices like Laptops Internet access HD video streaming Printer


AIRCRAFTS The whole airways communication are performed on the basis of radio waves. Hence passengers face the problem in communication media. This problem can be overcome by using Li- Fi , since light waves will not interfere with radio waves.

Street Lamps (As free Access Points) : :

Street Lamps (As free Access Points) : There are millions of street lamps deployed around the world. Each of these street lamps could be a free access point.


VLC SMARTPHONES The first VLC Smartphone was presented by Consumer Electronics in January, 2014 The phone uses Wysips connect – a clear thin layer of crystal glass is added to the small screens Smartphone makes them solar powered. Smartphone could get 15% more battery life in a day Can communicate using Li- Fi .


ADVANTAGES Data rate greater than 10 Gbps ; Theoretically allowing HD film to be downloaded in 30 seconds Can be used anywhere, even in RF restricted areas; Since light waves will not interfere with radio waves. Mostly LED light bulbs are used, which consumes less energy. Hence cost efficient. As light waves cannot penetrate through walls, the data cannot be intercepted; Thus provides secured communication. Efficient alternative to radio based wireless; since it is quick and reliable.


LIMITATIONS Visible light cannot penetrate through solid objects. A major challenge of LiFi is how the receiving device will transmit back to transmitter. Interferences from external light sources like sunlight, in the path of transmission will cause interruption in the communication. Data transmission can be easily blocked by any object placed in front of LED source.


CONCLUSION Thus, if Li- Fi technology can be put into practical use, every bulb can be used as an alternative to Wi-Fi hotspots. It provides simple, faster and efficient wireless data communication. Li- Fi will make us to proceed towards the cleaner, greener, safer and brighter future.

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