Dr. Sheikh Sajid


Dr  Sajid completed his PhD with Excellence in 2007 from Graz University of Technology, and developed an expertise in Optical Wireless Communications. Dr Sajid has published around 25 Journal articles and more than 50 peer reviewed conference papers. Dr Sajid organized the First IEEE Colloquium on Optical Wireless Communications at the CSNDSP 2008 in Graz, and the subsequent second and third Colloquiums in UK (2010) and Poland (2012). He worked as an Assistant Professor of Electrical Engineering from 2007 to 2011 and established the graduate (MS/PhD) programs at his Department. He supervised the first ever MS thesis to be completed at his Department and has subsequently supervised 10 MS works. From Fall 2011 to Fall 2015, he served working as an Associate Professor of Electrical Engineering and successfully supervised the first ever doctoral thesis to be completed and defended at his Department. His research contributions have led him to invitations of chairing and organizing IEEE Conferences and sessions on Optical Wireless Communications. For his academic achievements and his services to his Department and University, Dr Sajid was promoted to the rank of Professor in Electrical Engineering in 2016.

His published work has initiated new directions of research within the optical wireless domain exhibited by the citations of his papers summarized below

[J1] S. Sheikh Muhammad, B. Flecker, E. Leitgeb and M. Gebhart Characterization of Fog Attenuations in Terrestrial Free Space Optical Links, in Journal of Optical Engineering, vol. 46, No. 6, June 2007  [97 citations] .

[C1] S. Sheikh Muhammad, P. Koehldorfer, E. Leitgeb Channel Modeling for Terrestrial FSO, in IEEE ICTON, pp. 407-410, Barcelona, Spain, July 2005 [126 citations]

Currently, the total number of citations of his various academic works stand at 1282 and his current H-factor is 21.

Professor Dr Sajid was nominated as a Guest Editor for the Journal of Communications special issue on Optical Wireless communications and the IET’s special issue on “Photonic and Optical Wireless Network” whereby contributions from all over the globe were solicitated, peer-reviewed and published in September 2009 and March 2012, respectively. He recently acted as the Guest Editor for the special issue of the Transactions on Emerging Telecommunication Technologies (ETT) on “Optical Wireless Communications” published in June 2014.


Theoretical Advances in Optical Wireless Communications

During the last few years, we are seeing a large and steady growth of ultrafast broadband wireless access networks coming from the consumers in medical, educational, financial, commercial and entertainment sectors. There are two existing capable technologies offering these services which are radio and optical wireless communications. While radio offers mobility and ubiquitous feature for indoor and outdoor communications, it suffers from modulation bandwidth bottleneck, whereas optical wireless communications offers the flexibility in deployment, security as well as ultra-high modulation bandwidth. Recently, there is a considerable interest in both outdoor and indoor optical wireless communications for fulfilling the high data rate requirements and for possible integration in the evolving 5 G Networks.

Optical Wireless Communications is an evolving technology with applications ranging from infra-red operated remote controls (most sold devices) to inter-satellite high data rate laser based communications links. The application areas of optical wireless include optical interconnects, terrestrial links, Inter-satellite links, inter-high altitude platforms (HAP), inter-UAV, HAP-GEO links and links from HAP/aircraft to ground, visible light based LANs, high definition TV entertainment systems, and high speed communication within high-speed trains and passenger aircrafts.

This talk would initiate the audience into recent theoretical research in different aspects of Optical Wireless Communication systems including propagation modeling, channel modeling, coded-modulation techniques and the application of Network information theory to optical wireless networks.

In the propagation modeling domain, the utilization of the Radiative Transfer Equations (RTE) for accurately modeling the optical beam interaction with the atmospheric particles will be emphasized. The talk would also clarify that the most serious deterrent to the wide scale adaptability of terrestrial FSO is the aerosol based scattering in particular fog attenuation. The commonly held misconceptions regarding wavelength selection to combat attenuation would be clarified through results acquired through the RTE modeling.

The application of Network Information Theory to optical wireless networks has led to very interesting derivations of minimum Energy per bit requirement for reliable communication over an Optical Wireless Relay Channels (OWRC). Cooperative relaying can enhance the coverage and availability of optical wireless. An OWRC is the classical three node network comprising source, relay and destination nodes. Considering the nodes to be interconnected by optical wireless Gaussian links, the derived upper and the lower capacity bounds would be discussed. It will be shown that upper and lower bounds tend to converge when peak signal to noise ratio is high.