07-07-2014, 02:22 PM
Li-Fi (Light Fidelity)
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Abstract
With the vast growing gadgets, their usage and their developments led to the advancement in the Wi-Fi which provides a technology so called Li-Fi.Li-Fi is a technology that makes use of LED light which helps in the transmission of data much more faster and flexible than data that can be transmitted through Wi-Fi.Light reaches nearly everywhere so communication can also go along with light freely. Light Fidelity is a branch of optical wireless communication which is an emerging technology. By using visible light as transmission medium, Li-Fi provides wireless indoor communication. The bit rate achieved by Li-Fi cannot be achieved by Wi-Fi..Dr herald Haas ,the professor of mobile communications at the university of Edinburgh school of engineering ,first time publically displayed the proof of Light Fidelity(Li-Fi) ,a method of Visible Light communication(VLC). Li-Fi is the transfer of data through light by taking fiber out of fiber optics andcan produce data rates faster than 10 megabits per second, which is speedier than your average broadband connection. in future where data for laptops, smart phones, and tablets is transmitted through the light in a room. And security would be snap – if you can’t see the light, you can’t access the data.
INTRODUCTION
Li-fi basically known as “light fedility” is an outcome of twenty first century. The basic ideology behind this technology is that the data can be transmitted through LED light whose intensity varies even faster than the human eye. As the transmission of the data takes place through the light emitting diodes (LED’s) the amount is comparatively small .In modern times, it is called as the optimized version of WI-FI .The advantageous thing is the wireless communication which decreases the cost enormously. HARALD HASS, who is considered to be the father of Li-fi from university of Edinburgh, UK says that the heart of this technology lies in the intensity and the potential of the light emitting diodes. The major reason which lead the modern man through this invention is that the confinement of Wi-Fi to comparatively small distance. As there are more and more devices coming up day-by-day the signals are being clogged up due to heavy traffic, there arised a need for an error free transmission technology.And the solution to this problem was the Li-fi technology. It has been designed in such a way that it overcomes the disadvantages that occurs during the usage of wi-fi. In general terms, Li-fi works even under water thereby causing a great benefit to the military.li-fi technology isVery simple if the LED is on, you transmit a digital 1, if it’s off you transmit a 0,They can be switched on and off very quickly, which gives nice opportunities for transmitted data. 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 eye cannot notice, so the output appears constant. More sophisticated techniques could dramatically increase VLC data rate.Terms at the University of Oxford and the University of Edingburgh are focusing on parallel data transmission using array of LEDs, where each LED transmits a different data stream. Other group are using mixtures of red, green and blue LEDs to alter the light frequency encoding adifferent data channel.Li-Fi, as it has been dubbed, has alreadyachieved blisteringly high speed 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.
WORKING TECHNOLOGY
Radio waves are replaced by lightwaves 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.
Its working is very simple if the LED is 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.” So what you require at all are 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. 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 witheach frequency encoding a different data channel. Such advancements promise a theoretical speed of 10 Gbps –meaning you can download a full high-definition film in just 30 seconds. Simply awesome! But blazingly fast data rates and depleting bandwidths worldwide are not the only reasons that give this technology an upper hand. Since Li-Fi uses just the light, it can be used safely in aircrafts and hospitals that are prone to interference from radio waves. This can even work underwater where Wi-Fi fails completely, thereby throwing open endless opportunities for military operations.
CONCLUSION
Li-Fi is the upcoming and on growing technology acting as compe-tent for various other developing and already invented technologies. Since light is d major source for transmission in this technology it is very advantageous and implementable in various fields that can’t be done with the Wi-Fi and other technologies. Hence the future appli-cations of the Li-Fi can be predicted and extended to different plat-forms like education fields, medical field, industrial areas and many other fields.