Telecommunication and Radio Navigation

Our long-medium term research is focused on Telecommunication Systems and Radio Navigation. The main emphasis of our research is on the application of advanced and/or computationally efficient signal processing algorithms for improving the performance, capacity and quality of wireless communications (indoors, vehicular, satellite, the novel high altitude platforms etc.) and radio navigation systems. In order to meet the critical need for enhanced Telecommunication systems, the parameters that limit performance (propagation environments, interference scenarios, the effect of other users etc.) must be comprehensively investigated and understood. The Group's work involves an extensive range of theoretical analysis, computer simulations and modelling tools in order to obtain full assessment of these factors and their effects on system's performance. This work is complemented by a radio communications laboratory in both research and education. In addition, our research is usually carried out in collaboration with other partners in Sweden and abroad.  

BTH research within this subject area

Our research expertise is multidisciplinary and is at the intersection of telecommunications theory, digital wireless communication, applied signal processing and mathematics, antennas and electromagnetic wave propagations, information theory and radio navigation. In Telecommunications, a major interest of the group is to study and promote space-time signal processing and multiple-transmitter multiple-receiver (MTMR) antenna technology in wireless communication systems. This is also known as multiple-input multiple-output (MIMO) technology. While a variant of this approach was proposed as an option for third generation (3G) mobile systems, multiple antennas will likely be mandatory in next generation wireless communication systems. MTMR antenna systems are important since they increase potential data rate or capacity through multiplexing gain and enhance link quality through diversity benefit. We have applied this technology to different systems including indoor communications, cellular mobile radio terminals, satellite systems and High Altitude Platforms (HAPs). 

HAPs is an emerging novel technology which is preserving many of the advantages of both satellite and terrestrial systems and recently started to attract considerable attention in Europe through the European Community COST 297 Action, in which Abbas Mohammed and Tommy Hult from BTH are the Swedish representatives to the Action. HAPs are airships, balloons or planes, operating in the stratosphere, at altitudes of typically 17-22 km. At this altitude (which is well above commercial aircraft height), they can maintain a quasi-stationary position, and support payloads to deliver a range of communication services including emergency communications.

In addition, the group has always been at the forefront of research into new Telecommunication systems and novel technologies such as HAPs, LTE, Cognitive Radio, WiMAX, and short-range wireless communication systems (e.g., UWB).

In Radio Navigation, the main goal of our research is to investigate novel signal processing techniques for mitigating interference sources in order to enhance the performance and precision in these systems. In particular, Professor Abbas Mohammed has discovered new signal processing techniques for the identification of skywave interference in long range navigation (Loran-C) receivers and demonstrated them in a prototype receiver working in real-time. This work has received the Best Paper Award from the International Loran Association (ILA), USA 

The performances of many radio communication and navigation systems are critically dependent on matching the system design to radio frequency propagation characteristics and the propagation environment. Thus, our research aims to contribute to a better understanding of environment effects on radio wave propagation within the individual systems and the coexistence scenarios with other systems in order to offer improvements to existing systems and propose new applications. 

Application areas

Telecommunication Systems and Radio Navigation are among the hottest research fields nowadays. They constitute a vital role in the nation's economical and social strength. They are crucial in many of the services deemed essential for everyday modern life in many parts of the world and will continue to have a dramatic effect on our society.  The group is very active within the European Community projects (Cost 280, 296, 297, IC0802) which include participants from academia, industry and standardisation bodies. Many aspects of our research address the interest of the industry to introduce terrestrial and satellite-based broadband telecommunication systems, which are making optimal use of the limited frequency spectrum. Increasing the system capacity, improving the quality of communications, and enhancing the positioning/navigation accuracy is of great importance to all telecommunications and navigation companies and the operators of these systems. Our research on MIMO technology has shown that these goals and others can be accomplished in a variety of environments and systems. In addition, many communication technologies such as wireless sensor networks also play a vital role in medical, security, environmental and other applications.   

The group has always been at the forefront of research into new Telecommunication systems and technologies such as High Altitude Platforms (HAPs), Cognitive Radio, LTE, WiMAX, and short-range wireless communication systems (e.g., UWB). For example, currently our group is the Swedish representative within the European Community COST 297 Action concerning the novel HAPs technology.  HAPs are attractive for a large class of applications, among which telecommunications is certainly one of the most promising for the commercial revenue they can provide. Another crucial application of HAPs is that they can be deployed in emergency situations and disaster areas where normal telecommunication infrastructure has been disabled.

Links and further information

Contact: Professor Abbas MohammedDirector of Telecommunication and Radio Navigation Reserach, abbas.mohammed@bth.se

A general overview of our research published in Sydöstran News Paper - "Researcher with High-Flying Plans" (OBS. in swedish)

http://www.sydostran.se/index.52666--2-1.html (Opens in new window)

The Graduate School of Telecommunications (GST) 

http://www.ee.kth.se/education/gst/index.php (Opens in new window)

selected publications

Abbas Mohammed and Zhe Yang, "Next Generation Broadband Services from High Altitude Platforms", Chapter 12 in Book "Fourth-Generation Wireless Networks: Applications and Innovations", IGI Global, Jan 2010.

Tommy Hult, Abbas Mohammed, Zhe Yang and David Grace, "Performance of a Multiple HAP System Employing Multiple Polarization", Invited Paper, Special Issue of Springer Wireless Personal Communications Journal, Volume 52, Issue 1, pp. 105-117, Jan 2010. 

Tommy Hul and Abbas Mohammed, "The Effect of Mutual Coupling on a HAP Diversity System using Compact Antenna Arrays", Special Issue on Mutual Coupling in Antenna Arrays, Hindawi International Journal of Antennas and Propagation, 2010.

Abbas Mohammed and Tommy Hult, "Capacity Evaluation of a High Altitude Platform Diversity System Equipped with Compact MIMO Antennas", International Journal of Recent Trends in Engineering (IJRTE), Academy Publisher, Vol. 1, No. 3, pp. 244-247, May 2009.

Abbas Mohammed and Zhe Yang, "Broadband Communications and Applications from High Altitude Platforms", International Journal of Recent Trends in Engineering (IJRTE), Academy Publisher, Vol. 1, No. 3, pp: 239-243, May 2009.

Tommy Hult, Abbas Mohammed, David Grace and Zhe Yang, "Performance of a Multiple HAP System Employing Multiple Polarization", Invited Paper, Special Issue of Springer Wireless Personal Communications Journal, No. 11277; Article No. 9511 2008, May 2008.

Abbas Mohammed, Shlomi Arnon, David Grace, Marina Mondin and Ryu Muira, "Advanced Communication Techniques and Applications for High Altitude Platforms", Editorial to the Special Issue "Advanced Communication Techniques and Applications for High Altitude Platforms",  EURASIP International Journal of Communications and Networking, April 2008.
Prof. Abbas Mohammed is the lead editor to this special issue.

Tommy Hult, Abbas Mohammed and David Grace, "WCDMA Capacity and Coverage Enhancement from Multiple High Altitude Platform Configurations", EURASIP International Journal of Communications and Networking, April 2008. Special Issue on "Advanced Communication Techniques and Applications for High Altitude Platforms".

Zhe Yang, Abbas Mohammed, Tommy Hult, and David Grace, "Downlink Coexistence Performance Assessment  and Techniques of WiMAX Services in High Altitude Platforms and Terrestrial Deployments", EURASIP International Journal on Wireless Communications and Networking, April 2008. Special Issue on "Advanced Communication Techniques and Applications for High Altitude Platforms".

Zhe Yang, Abbas Mohammed and Tommy Hult, "Performance Evaluation for WiMAX Broadband from High Altitude Platform Cellular System and Terrestrial Coexisting Capability", EURASIP International Journal on Wireless Communications and Networking, April 2008. Special Issue on "Advanced Communication Techniques and Applications for High Altitude Platforms".

Professor Abbas Mohammed

Abbas Mohammed is a Professor of Telecommunications Theory and the Director of Telecommunication and Radio Navigation Research at the School of Engineering, Blekinge Institute of Technology, Sweden. He was awarded the PhD degree from Liverpool University, UK, in 1992 and the Swedish Docent degree in Radio Communications and Navigation from Blekinge Institute of Technology in 2001. He was the recipient of the Blekinge Research Foundation Award "Researcher of the Year Award and Prize" for 2006.

From 1993 to 1996, he was a Research Fellow with the Radio Navigation Group, University of Wales (Bangor), UK. From 1996 to 1998, he was with the University of Newcastle, UK, working on a European collaborative project within the ACTS (Advance Communications Technologies and Services) FP4 Research Programme that investigated 3G Satellite-UMTS systems. He was also employed by Ericsson AB, where he consulted on Power Control standardization issues for 3G. He has been a visiting lecturer to several Swedish universities. He is a Fellow of The Institution of Electrical Engineering. In 2006 he received Fellowship of the UK's Royal Institute of Navigation "in recognition of his significant contribution in navigation and in particular to advanced signal processing techniques that have enhanced the capability of Loran-C". He is an Associate Editor to the International Journal of Navigation and Observation, a Board Member of the IEEE Signal Processing Swedish Chapter, and an Editorial Board Member of the Radio Engineering Journal and the Mediterranean Journal of Electronics and Communications.

He has also been a Guest Lead Editor for several special issues of international journals. He is the author of over 180 publications, including many book chapters and articles in peer reviewed Journals including invited special issues, in the fields of signal processing, telecommunications and navigation systems. He has also developed techniques for measuring skywave delays in Loran-C receivers and received a Best Paper Award from the International Loran Association, USA, in connection to this work.

He is the Swedish representative and member of the management committee to the European Community COST 280, 296, 297 (High Attitude Platforms - HAPs) and IC0802 Actions. He is the BTH Director of the Graduate School of Telecommunications (a collaborative consortium in research and education between 4 Swedish universities).

Professor Mohammed's research interests are in space-time signal processing and MIMO systems, channel modelling, antennas and propagation, satellite and high altitude platform communications, cognitive radio and dynamic spectrum access, and radio navigation systems.

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