Li-Fi is a visible light communication technology that uses LED bulbs to transmit data by varying the intensity of light. It was developed by researchers at the University of Edinburgh including Dr. Gordon Povey and Prof. Harald Haas, who coined the term "Li-Fi" in 2011 when demonstrating streaming video from an LED lamp. Li-Fi transmits data through subtle, rapid variations in LED light intensity that are undetectable to the human eye. Researchers have achieved data rates over 500 megabytes per second in the lab, faster than most broadband connections.
W
hether you’re using wireless internet in a coffee shop,stealing it from the guy next door, or competing for bandwidth at a conference, you have probably gotten frustrated at the slow speeds you face when more than one device is tapped into the network. As more and more people and their manydevices access wireless internet, clogged airwaves are going tomake it.
One German physicist, Harald Haas has come up with asolution he calls “data through illumination” –taking the fibberout of fiber optic by sending data through an LED light bulbthat varies in intensity faster than the human eye can follow.It’s the same idea band behind infrared remote controls but farmore powerful.
Haas says his invention, which he calls D-Light,can produce data rates faster than 10 megabits persecond, which is speedier than your average broadbandconnection. He envisions a future where data for laptops,smart phones, and tablets is transmitted through the light in aroom. And security would be snap – if you can’t see the light,you can’t access the data.
Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. This very property of optical current is used in Li-Fi setup.The operational procedure is very simple-,data from the internet and local network is used to modulate the intensity of the LED light source if any undetectable to the human eye. The photo detector picks up signal, which is converted back into a data stream and sent to the client.
The client can communicate through its own LED output or over the existing network. An overhead lamp fitted with an LED with signal-processing technology streams data embedded in its beam at ultra-high speeds to the photo-detector. A receiver dongle then converts the tiny changes in amplitude into an electrical signal, which is then converted back into a data stream and transmitted to a computer or mobile device.
At the heart of this technology, a new generation of high-brightness light-emitting diodes. Very simply, if the LED is ON, user can transmit a digital string of 1, if it’s OFF then user can transmit a string of 0. It can be switched ON and OFF very quickly, which gives instant opportunity for transmitting data. It is possible to encode data in the light by varying the rate at which the LEDs flicker ON and OFF to pass different strings of 1s and 0s. The modulation is so fast that the human eye doesn’t notice. There are over 14 billion light bulbs used across the world, which needs to be replaced with LEDs ones that transmit data.
Lifi(Light fidelity)-Efficient use of visible spectruminventionjournals
ABSTRACT : LEDs are beginning to be used in every home and office which makes LED’s light ideal for ubiquitous data transmitter This means that everywhere where LEDs are used, lighting bulbs can bring not only the light but wireless connection at the same time. With increasing demand for wireless data, lack of radio spectrum and issues with hazardous electromagnetic pollution, LiFi is a new wireless communication technology which enables a wireless data transmission through LED light. LiFi appears as a new greener, healthier and cheaper alternative to WiFi. Li-Fi is the emerging area of technology is also known as Visible Light Commu-nications (VLC) .Moreover LiFi makes possible to have a wireless Internet in specific environments (hospitals, airplanes etc.) where WiFi is not allowed due to interferences or security considerations.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
How the li-fi technology came into existence.How it works and what are the advantages and disadvantages of li-fi technology.
For new topics visit my blog http://tulasikrishnaravi.blogspot.in/
Li-Fi will be a great advanced technology in Upcoming High Speed Wireless World.This slide is a basic informational Slide about Li-Fi. I hope after reading this slide, You will get the basic knowledge about Li-Fi. This slide was made for my University Presentation. Information was taking from Google.
This is one of the most emerging technology for the transmission of information over light. Transmission over light is faster than any other in the universe. because the light is the fastest thing in the universe.
W
hether you’re using wireless internet in a coffee shop,stealing it from the guy next door, or competing for bandwidth at a conference, you have probably gotten frustrated at the slow speeds you face when more than one device is tapped into the network. As more and more people and their manydevices access wireless internet, clogged airwaves are going tomake it.
One German physicist, Harald Haas has come up with asolution he calls “data through illumination” –taking the fibberout of fiber optic by sending data through an LED light bulbthat varies in intensity faster than the human eye can follow.It’s the same idea band behind infrared remote controls but farmore powerful.
Haas says his invention, which he calls D-Light,can produce data rates faster than 10 megabits persecond, which is speedier than your average broadbandconnection. He envisions a future where data for laptops,smart phones, and tablets is transmitted through the light in aroom. And security would be snap – if you can’t see the light,you can’t access the data.
Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. This very property of optical current is used in Li-Fi setup.The operational procedure is very simple-,data from the internet and local network is used to modulate the intensity of the LED light source if any undetectable to the human eye. The photo detector picks up signal, which is converted back into a data stream and sent to the client.
The client can communicate through its own LED output or over the existing network. An overhead lamp fitted with an LED with signal-processing technology streams data embedded in its beam at ultra-high speeds to the photo-detector. A receiver dongle then converts the tiny changes in amplitude into an electrical signal, which is then converted back into a data stream and transmitted to a computer or mobile device.
At the heart of this technology, a new generation of high-brightness light-emitting diodes. Very simply, if the LED is ON, user can transmit a digital string of 1, if it’s OFF then user can transmit a string of 0. It can be switched ON and OFF very quickly, which gives instant opportunity for transmitting data. It is possible to encode data in the light by varying the rate at which the LEDs flicker ON and OFF to pass different strings of 1s and 0s. The modulation is so fast that the human eye doesn’t notice. There are over 14 billion light bulbs used across the world, which needs to be replaced with LEDs ones that transmit data.
Lifi(Light fidelity)-Efficient use of visible spectruminventionjournals
ABSTRACT : LEDs are beginning to be used in every home and office which makes LED’s light ideal for ubiquitous data transmitter This means that everywhere where LEDs are used, lighting bulbs can bring not only the light but wireless connection at the same time. With increasing demand for wireless data, lack of radio spectrum and issues with hazardous electromagnetic pollution, LiFi is a new wireless communication technology which enables a wireless data transmission through LED light. LiFi appears as a new greener, healthier and cheaper alternative to WiFi. Li-Fi is the emerging area of technology is also known as Visible Light Commu-nications (VLC) .Moreover LiFi makes possible to have a wireless Internet in specific environments (hospitals, airplanes etc.) where WiFi is not allowed due to interferences or security considerations.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
How the li-fi technology came into existence.How it works and what are the advantages and disadvantages of li-fi technology.
For new topics visit my blog http://tulasikrishnaravi.blogspot.in/
Li-Fi will be a great advanced technology in Upcoming High Speed Wireless World.This slide is a basic informational Slide about Li-Fi. I hope after reading this slide, You will get the basic knowledge about Li-Fi. This slide was made for my University Presentation. Information was taking from Google.
This is one of the most emerging technology for the transmission of information over light. Transmission over light is faster than any other in the universe. because the light is the fastest thing in the universe.
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Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi would use transceiver-fitted LED lamps that can light a room as well as transmit and receive information. Since simple light bulbs are used, there can technically be any number of access points.
Smart phones, tablets, and the rise of the Internet of Things are driving an insatiable demand for wireless capacity. This demand requires networking and Internet infrastructures to evolve to meet the needs of current and future multimedia applications. Wireless HetNets will play an important role toward the goal of using a diverse spectrum to provide high quality-of-service, especially in indoor environments where most data are consumed. An additional tier in the wireless HetNets concept is envisioned using indoor gigabit small-cells to offer additional wireless capacity where it is needed the most. The use of light as a new mobile access medium is considered promising. In this article, we describe the general characteristics of WiFi and VLC (or LiFi) and demonstrate a practical framework for both technologies to coexist. We explore the existing research activity in this area and articulate current and future research challenges based on our experience in building a proof-of-concept prototype VLC HetNet.
This paper attempts to clarify the difference between visible light communication (VLC) and Light-Fidelity (LiFi). In particular, it will show how LiFi takes VLC further by using light emitting diodes (LEDs) to realise fully networked wireless systems. Synergies are harnessed as luminaries become LiFi attocells resulting in enhanced wireless capacity providing the necessary connectivity to realise the Internet-of-Things (IoT), and contributing to the key performance indicators for the 5th generation of cellular systems (5G) and beyond
1. Li-Fi is a VLC, visible light communication, technology developed by a team of
scientists including Dr Gordon Povey, Prof. Harald Haas and Dr Mostafa Afgani at
the University of Edinburgh. The term Li-Fi was coined by Prof. Haas when he
amazed people by streaming high-definition video from a standard LED lamp, at TED
Global in July 2011. Li-Fi is now part of the Visible Light Communications (VLC)
PAN IEEE 802.15.7 standard. “Li-Fi is typically implemented using white LED light
bulbs. These devices are normally used for illumination by applying a constant current
through the LED. However, by fast and subtle variations of the current, the optical
output can be made to vary at extremely high speeds. Unseen by the human eye, this
variation is used to carry high-speed data,” says Dr Povey, , Product Manager of the
University of Edinburgh's Li-Fi Program ‘D-Light Project’.
Introduction of Li-Fi Technology
In simple terms, Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light
instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi
would use transceiver-fitted LED lamps that can light a room as well as transmit and
receive information. Since simple light bulbs are used, there can technically be any
number of access points.
This technology uses a part of the electromagnetic spectrum that is still not greatly
utilized- The Visible Spectrum. Light is in fact very much part of our lives for
millions and millions of years and does not have any major ill effect. Moreover there
is 10,000 times more space available in this spectrum and just counting on the bulbs in
use, it also multiplies to 10,000 times more availability as an infrastructure, globally.
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 LED intensity is modulated so
rapidly that human eyes cannot notice, so the output appears constant.
More sophisticated techniques could dramatically increase VLC data rates. Teams at
the University of Oxford and the University of Edinburgh are focusing on parallel
data transmission using arrays of LEDs, where each LED transmits a different data
stream. Other groups are using mixtures of red, green and blue LEDs to alter the
light's frequency, with each frequency encoding a different data channel.
Li-Fi, as it has been dubbed, has already achieved blisteringly high speeds in the lab.
Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data
rates of over 500 megabytes per second using a standard white-light LED. Haas has
set up a spin-off firm to sell a consumer VLC transmitter that is due for launch next
2. year. It is capable of transmitting data at 100 MB/s - faster than most UK broadband
connections.
Genesis of LI-FI:
Harald Haas, a professor at the University of Edinburgh who began his research in the
field in 2004, gave a debut demonstration of what he called a Li-Fi prototype at the
TEDGlobal conference in Edinburgh on 12th July 2011. He used a table lamp with an
LED bulb to transmit a video of blooming flowers that was then projected onto a
screen behind him. During the event he periodically blocked the light from lamp to
prove that the lamp was indeed the source of incoming data. At TEDGlobal, Haas
demonstrated a data rate of transmission of around 10Mbps -- comparable to a fairly
good UK broadband connection. Two months later he achieved 123Mbps.
How Li-Fi Works?
Li-Fi is typically implemented using white LED light bulbs at the downlink
transmitter. These devices are normally used for illumination only by applying a
constant current. However, by fast and subtle variations of the current, the optical
output can be made to vary at extremely high speeds. This very property of optical
current is used in Li-Fi setup. The operational procedure is very simple-, if the LED is
3. on, you transmit a digital 1, if it’s 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 is required is some LEDs and a controller that code data into those LEDs. All one
has to do is to vary the rate at which the LED’s flicker depending upon the data we
want to encode. 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 light’s 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.
TTo further get a grasp of Li-Fi consider an IR remote.(fig 3.3). It sends a single data
stream of bits at the rate of 10,000-20,000 bps. Now replace the IR LED with a Light
Box containing a large LED array. This system, fig 3.4, is capable of sending
thousands of such streams at very fast rate.
4. Light is inherently safe and can be used in places where radio frequency
communication is often deemed problematic, such as in aircraft cabins or hospitals. So
visible light communication not only has the potential to solve the problem of lack of
spectrum space, but can also enable novel application. The visible light spectrum is
unused, it's not regulated, and can be used for communication at very high speeds