DescriptionNetworked visible light communications -also referred to as Li-Fi- are an exciting new field of development in communications. This tutorial looks at practical applications of Li-Fi. Networked visible light communications, also referred to as Li-Fi, promises quantum step improvements in area spectral efficiency while exploiting existing infrastructures by piggy-backing high speed data communication on existing lighting infrastructures. The visible light spectrum is unlicensed and 10,000 times larger than the range of radio frequencies between 0 Hz to 30 GHz. The use of the visible light spectrum for data communication is enabled by inexpensive and off-the-shelf available light emitting diodes (LEDs) which also form the basis for next generation energy efficient lighting. Individual LEDs can be modulated at very high speeds - 3.5 Gbit/s @ 2 m distance have been demonstrated as well as 1.1 Gbit/s @ 10m at the University of Edinburgh. Both demonstrations use micro LEDs with a total optical output power of 5 mW. LED lighting saves energy, and combining lighting and data communication adds additional energy saving benefits. Moreover, transforming the multiple light fixtures in a room into networked optical access points enables high density wireless networking referred to as optical attocell networks. While in radio frequency (RF) communication, multiple antennas as well as multiple transmission chains are required to achieve beamforming, this can simply be accomplished in Li-Fi by optical lenses. Because of this feature and the fact that light is spatially contained (and does not propagate through walls), effective interference management in high density optical attocell networks does not involve large computational complexity und very dense deployment of optical attocells is practically feasible. A by-product of the interference containment is enhanced security which could be exploited for new cybersecurity techniques. Recent research has shown that the area spectral efficiency indoors can be improved by a factor of 900 when using an optical attocell network . Thus it is possible to harness a vast and licence-free wireless transmission resource with existing devices, design optical access points to enable a new level of network densification without creating an unmanageable interference problem, thereby giving Li-Fi the capability to address jointly the issues of wireless data crunch, energy efficiency, security and simple transceivers for the large scale deployment of wireless devices. Links: * www.lifi-centre.com * www.purelifi.com *http://www.bbc.co.uk/programmes/p0213ck8 *http://www.lifi-centre.com/eucnc2014/ *http://www.boldtalks.com/en/speaker/speakers/harald-haas.html *http://www.bbc.co.uk/news/technology-26245544 Students View all
Professor Harald Haas holds the Chair for Mobile Communications at the University of Edinburgh, and in 2011 in his TEDTalk, which has now been viewed over 1.5 million times, he demonstrated that it is possible to turn LED light bulbs into broadband wireless transmission systems. He has pioneered ‘Li-Fi’, listed among the 50 best inventions in TIME Magazine 2011, holds 26 patents and has 20 pending patent applications, and is co-founder and chief scientific officer of pureLiFi Ltd. Professor Haas has published over 270 conference and journal papers including a paper in Science. His second textbook‚ ‘Principles of LED Light Communications Towards Networked Li-Fi‘ will be published by Cambridge University Press in early 2015. Professor Haas invented and has pioneered Spatial Modulation. His main research interests are wireless system engineering and digital signal processing, with a particular focus on optical wireless communications; hybrid optical wireless and RF communications; and energy and spectral efficient wireless communications. In 2012, Professor Haas was awarded the prestigious Established Career Fellowship from the UK Engineering and Physical Sciences Research Council (EPSRC). He was featured in the first edition of CNN's ‘Make Create Innovate‘ Programme in September 2012. In November 2013, a new Li-Fi Research and Development Centre was established, led by Professor Haas. This internationally leading UK centre will accelerate the adoption of Li-Fi and emerging wireless technology through engagement with major industrial partners, to fully harness the commercial and innovative potential of Li-Fi, and establish an exciting new $8 billion Li-Fi industry. The Centre is currently identifying new industrial partners and international electronics companies to collaboratively further develop Li-Fi technology. The Centre uses a National Instruments massive multiple input multiple output (MIMO) Testbed in its Optima Lab. In April 2014, Professor Haas was selected as one of ten RISE Leaders, in recognition of their engagement, influence and impact in scientific research. In August 2014, a new £12 million five-year joint project, ‘Towards Ultimate Convergence if All Networks‘ (TOUCAN), started work on drastically evolving Software Defined Networking (SDN). Professor Haas will lead the TOUCAN Lab, a multi-technology experimental platform to validate the TOUCAN vision, new solutions and architecture through a series of technology evaluation cycles, real-world user trials. The Li-Fi 'optical attocell network' developed in the Li-Fi Centre will be an essential part of this mix of innovative technologies. Li-Fi is innovative, and research and product development is central to the newly emerging Li-Fi industry, and in the future‚ to the ‘internet of everything‘.
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