Professor Haas’ current research focuses on three main areas (a) optical wireless communications, (b) spatial modulation, and (c) interference coordination in wireless networks. His work in these areas can be summarised as follows:
Optical wireless communications: His group published the first proof-of-concept results demonstrating that it is possible to exploit the high crest factor of orthogonal frequency division multiplexing (OFDM) commonly accepted as a disadvantage in radio frequeny (RF) communications, to turn commercially available light emitting diode (LED) light bulbs into broadband wireless transmission systems. This work was published in a book on “100 groundbreaking ideas” that could shape the next century, edited by Nobel Laureate Prof. Hänsch. Prof. Haas was invited to present at the annual Technology Entertainment Design (TED) Global conference in 2011 with a talk entitled: Wireless data from every light bulb. By the time of writing, the video of the talk has been watched 877,000 times. He was finalist for the World Technology Award at the 2011 World Technology Summit in New York, and is now Fellow of the World Technology Network (WTN). Later, the TIME Magazine featured his work as one of the “50 Best Inventions in 2011″ in their 28 November 2011 issue. Haas’ work on optical wireless communcations has appeared in several international media channels such as: BBC (“click” program), NPR, CNBC, New York Times, Wired UK, NewScientist, Economist, and it featured in the ‘Cubed Webzine’ of the British Council. He has launched a university spin-out company, pureVLC Ltd. The company has acquired seed funding from an angel syndicate. Currently he is working one day per week for pureVLC Ltd and holds the position of CTO. In 2011 he published 7 journal papers in optical wireless communications including an overview in the IEEE Communications Magazine. He has been collaborating with Airbus Germany and analysed the possibility of optical wireless communications in an aircraft cabin. In a recent paper he developed an analytical framework that enabled a comprehensive analysis of all the potential digital modulation techniques suitable for optical wireless communications and showed for the first time that among all existing digital modulation techniques OFDM achieves the highest spectral efficiency when only intensity modulation (IM) / direct detction (DD) are available. Professor Haas has been the chair of the 2nd Optical Wireless Communications Workshop at IEEE Globecom 2011, he is co-chair of the 3rd Optical Wireless Communications Workshop at IEEE Globecom 2012, TPC member for the IEEE Summer Topicals 2012 of the IEEE Photonics Society, and guest editor of the EURASIP special issue on “Visible Light Communications”. Prof. Haas is involved in the photonics EPSRC network, UNISON, and the communications EPSRC network, ComNet, and has been co-organiser of annual summer schools and a workshop, and he is initiator of a joint summer school between UNISON and ComNet in June 2012.
Spatial modulation (SM): SM is a radically new wireless transmission technique that combines data modulation and multiple-input-multiple-output (MIMO) in a novel fashion. SM as originally proposed by Prof Haas and his reasearch group, and has been initially investigated under EPSRC project (EP/G011788/1). The leading transaction paper on SM has been cited 61 times (Web of Science). The recent overview article published in the IEEE Communications Magazine was among the top 10 downloads of the IEEE Communications Society (Comsoc) in December 2011. The full list of publications can be found here. For the first time the practical feasibility of SM could be demonstrated on the UK testbed of the UK-China Science Bridge project R&D on Beyond 4G Wireless Mobile Communications (EP/G042713/1) at the end of 2011. This has involved the collaboration of research groups from: Heriot-Watt, Bristol and Edinburgh.
Interference coordination in wireless networks: In collaboration with DOCOMO Euro Labs (Munich) Prof Haas’ group proposed an entire new and pioneering framework for cooperative, self-organising interference mitigation in cellular wireless networks based on one key invention, the “busy burst” principle. This invention solves one of the most fundamental problems in wireless communications, namely that a new transmitter in a wireless network cannot sense the location of a vulnerable receiver (also called the hidden node problem) where a transmission would cause detrimental interference to the ongoing transmission.