Effect of Antenna Beam Pattern and Layout on Cellular Performance in High Altitude Platform Communications

High Altitude Platforms may offer high spectrum efficiency by deploying multi-beam, multi-cell communications networks. The properties of the antennas carried by the HAP payload are key to the effective exploitation of these benefits. This paper compares different models for the antenna sidelobe region and quantifies, in each case, the carrier to interference ratio for a 3 channel re-use plan. Networks of 121 and 313 cells are compared. We show how the ITU recommended pattern for the 47/48 GHz band leads to pessimistic results compared to an adapted pattern which fits that of measured data for an elliptic beam lens antenna. The method is then extended to consider other radiation patterns. Spectrum sharing issues are explored with reference to further ITU recommendations and comparison with measurement data. Finally, an ITU type cellular layout which uses the same antenna for each cell is compared to an alternative hexagonal layout where each cell has equal size. John Thornton is a physics graduate of the University of York, UK, obtained an MSc. in microwave physics from the University of Portsmouth, UK, in 1995 and a PhD from the UK's Open University in 2002. He has held research posts at the Rutherford Appleton Laboratory, UK, developing sub-millimetre wave solid state sources and receivers, and at the University of Oxford, on projects including passive radar transponders, array antennas and superconducting filters. In 2000 he returned to York to join the Department of Electronics as a Research Fellow, where his research interests include microwave techniques, wireless broadband and scanning antennas. David Pearce BA(Cantab), DPhil(York) MIEEE, AMIEE, is a lecturer in the Department of Electronics in the University of York and has worked in the field of Fixed Wireless Access schemes for the last five years. Prior to this he worked developing new copper-based local area network schemes in both academia and industry; including heavy involvement in the standardisation work for ISO-8802.5 token ring. Current research interests are focused on media access schemes for multimedia traffic and adaptive techniques for optimising the bandwidth efficiency of wireless networks. David Grace received his MEng in Electronic Systems Engineering and D.Phil from the University of York, UK in 1993 and 1999 respectively. Since 1994 he has been a member of the Communications Research Group where he is now a Senior Research Fellow whose current interests include radio resource management for broadband communications, particularly from high-altitude platform, and terrestrial ad hoc networks. He is Principal Scientific Officer for CAPANINA, a major European Framework 6 project developing broadband communications from high-altitude platforms. He has been an invited speaker at several conferences and industrial locations in the fields of HAP systems. He is a nominated Researcher in the European NEWCOM Network of Excellence, and a Director of SkyLARC Technologies Ltd, a York based company, specialising in broadband communications from aerial platforms. He is a member of IEE and IEEE. Masayuki Oodo received B.E., M.E., and D.E. degrees in Electrical and Electronic Engineering from Tokyo Institute of Technology, Japan, respectively in 1992,1994, and 1997. In 1997, he joined the Communications Research Laboratory (CRL), now part of the National Institute of Information and Communication Technology (NICT). Since July 2004 he has been a visiting research fellow at the University of York. His research interests are array antennas for wireless communications and frequency-sharing between HAPS and other systems. Dr. Oodo received the Paper Presentation Award from IEEJ (The Institute of Electrical Engineers of Japan) in 1995, the Young Scientist Award from URSI in 1996, the Young Engineer Award from IEICE (The Institute of Electronics, Information and Communication Engineers) of Japan in 1997, and the Young Engineer Award from IEEE AP-S Tokyo Chapter in 1998. Konstantinos Katzis received his BEng degree in Computer Systems Engineering in 2000 and his MSc in Radio Systems Engineering in 2001, both from the University of Hull, UK. Since 2001 he has been a member of the Communications Research Group at York where he has been working on Resource Allocation Techniques for HAPs for his PhD degree. Currently he is a Research Associate working on Radio Resource Management for the European project CAPANINA. His current research interests include Resource allocation and spectrum management, multiple access schemes and medium access control protocol modelling. Tim Tozer MA(Cantab), CEng, FIEE, MIEEE, is Senior Lecturer in Electronics at York, since 1987, and leader of the Communications Research Group. Research interests include: wireless access techniques; multi-user, satellite and High Altitude Platform communications. He has held numerous grants and research contracts from industry, government and international organisations, and is a named author on over 180 technical publications. He is active in the IEE Professional Network on Satellite Systems and Applications. Tim is a regular invited presenter at international conferences, workshops and tutorials, in the fields of VSAT and HAPs communications. He has previous experience in industry, including work on military satellite systems at DERA (now QinetiQ). Tim is also Managing Director of SkyLARC Technologies Ltd.