IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Issue: 03 | Mar-2015, Available @ http://www.ijret.org 435 Li-Fi (LIGHT FIDELITY) – THE CHANGING SCENARIO OF WIRELESS COMMUNICATION Nitin Vijaykumar Swami 1 1 Computer Engineering Department, Shri Yogeshwari Polytechnic College, Ambajogai, Beed Abstract As per the growing demands of wireless communication there is enormous new technologies participating to make sophisticated environment for an end user. In a recent survey of International Telecommunication Union (ITU) it was found that the number of mobile phone subscribers has exceeds seven billion subscriptions at the end of 2014 using more than 10 to 15 internet utility apps which is more than the entire population of planet. To serve this increasing number and size of wireless communication system the German physicist – Harald Haas proposed a “Li–Fi technology” which he calls “Data through illumination” or “D-Light”. Li- Fi is a new approach of VLC which has much more similar working of a OFC communication system providing data rates of ten’s of Gbps. In this technology data is interpreted by the LED’s ON/OFF concepts. This paper gives a brief focus on Li-Fi technology, it’s working principal, some misconceptions about Li-Fi and related researches like Nobel Prize winning Blue Light emitting diode, Optoelectronic integrated circuit (OEIC) receiver, etc. Keywords: Li- Fi, VLC, Visible light communication, photo detector, optoelectronic integrated circuit, OEIC receiver, AP. --------------------------------------------------------------------***--------------------------------------------------------------------- 1. INTRODUCTION The statistics of ITU said that the use of mobile and internet is increased so that there is around 11 Exabyte (10 18 ) of data transferred through mobile networks [1] . When we consider the other electronics for communication it will surely exceed some more tens of Exabytes. And also due to increase in various communication systems there is no doubt of electromagnetic spectrum band gets occupied within a few next tens of decades. Over the past decade, significant research efforts have been directed towards exploring alternative parts of the electromagnetic spectrum that could potentially offload a large portion of the network traffic from the overcrowded RF domain [2] . The Li-Fi brings the best solution over these all problem which uses VLC. This fidelity concept is much more similar or you may call it as combination of OFC and Wi-Fi by adding and removing few elements. It works on LED’s ON/OFF concept encoded binary ‘one’ for light ON and binary ‘zero’ for light OFF condition. As we know the speed of light is about 1080 million km/hr and we are using the light source for data transmission, we can achieve the data rates in the range of Gbps. From the current experiments, the Li-Fi consortium believes it is possible to achieve more than 10Gbps speed, theoretically allowing a high definition film to be downloaded in 30 seconds [3] . 2. WORKING PRINCIPLE OF LI-FI: The working of Li-Fi is based on VLC, which uses visible light for data transmission. The visible light spectrum has wider range of hundreds of THz of free bandwidth, which is 10,000 times more than RF spectrum up to 30GHz. It uses LED to generate data stream which is connected to the internet or cellular system. As per the data stream the LED flickers at high rate which is not recognized by human eye.