Impact and Technical Profile

1. Made a number of world-first contributions to Optical Wireless (OW) systems introducing a large number of new concepts that led to world record performance improvements and data rates that increased as a result from few Mbit/s to multi Gbit/s with full mobility. Previous indoor mobile optical wireless systems operated typically at 30 Mbit/s (Djahani and Kahn IEEE TCOM 2000) to 100 Mbit/s (Audeh Kahn IEEE TCOM 95 and Boucouvalas and Vitsas, IEE Optoelectronics 2003).
2. Introduced OW systems that achieved 2.5 Gbit/s and 5 Gbit/s with full mobility [1, 7, 9, 12-15]. These improvements were achieved through the introduction of four new approaches: transmit beam angle adaptation (beam steering based on liquid crystal devices) [7, 8, 14, 15], beam power adaptation [3, 9, 14, 15], a two dimensional beam clustering method [1, 5, 6, 12, 13] and new diversity imaging receivers [1, 4, 8, 9, 12, 15] resulting in mobile OW channel bandwidths that improved from 38 MHz to over 8 GHz [8] with significant improvements in SNR.
3.  Investigated a number of concepts for the first time in the context of OW systems including relay nodes [5], the use of MCCDMA for multi-user operation [2-4, 10, 11] and has shown how his methods can reduce the impact of shadowing and enable mobile operation in a realistic indoor environment [3, 4, 11].
4. Most notably his work has shown how multi-gigabit mobile wireless communication systems can be realised opening the door to data rates beyond, for example, 40Gbit/s. These are mobile rates beyond those that can be supported in the radio frequency spectrum at present (and in the foreseeable future) and are becoming essential in view of the increased high definition (HD) and 3D media where projections by Cisco indicate that by 2020 over 90% of the Internet traffic will be high data rate video, mostly to dense deployments of handheld devices where currently 70% of the world wireless traffic starts and terminates indoor.
5. Published widely in the top IEEE communications conferences and journals and has received the Carter award, University of Leeds for the best PhD.