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Opportunistic Interference Cancellation in Cognitive Multiple Access Network

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Speaker: Behrouz Maham
Event date: Friday, 01 April 2011 02:15 pm - 03:00 pm
Place: Campus Kirchberg – 6, rue Richard Coudenhove-Kalergi, Luxembourg, building ‘F’ room F213

Abstract: In this talk, we investigates the problem of spectrally efficient operation of a multiuser uplink cognitive radio system in the presence of a single primary link. The secondary system applies opportunistic interference cancelation (OIC) and decode the primary signal when such an opportunity is created. We derive the achievable rate in the secondary system when OIC is used. This scheme has a practical significance, since it enables rate adaptation without requiring any action from the primary system. The exact expressions for outage probability of the primary user are derived, when the primary system is exposed to interference from secondary users. Moreover, approximated formulas and tight lower and upper bounds for the ergodic sum-rate capacity of the secondary network are found. Next, the power allocation is investigated in the secondary system for maximizing the sum-rate under an outage constraint at the primary system. We formulate the power optimization problem in various scenarios depending on the availability of channel state information and the type of power constraints, and propose a set of simple solutions. Furthermore, we propose a simple user selection strategy which achieve the optimal capacity given an interference constraint at the primary system. The simulations indicate both the accuracy of the analysis, and the fact that the spectral-efficient, low-complexity, flexible, and high-performing cognitive radio can be designed based on the proposed schemes. Finally, we briefly review our recent research in the context of resource-constrained cooperative networks.

Behrouz Maham received M.Sc in electrical engineering, from University of Tehran in 2007, and his PhD from the University of Oslo, Norway, in April 2010. He worked as a system engineer from 2006 till 2007 at Iran Telecommunication Research Center. From September 2008 to August 2009 he was with the Dept. of Electrical Engineering at Stanford University, USA. Currently, he is a Postdoctoral fellow at the University of Oslo. He has held visiting appointments at Aalto University (formerly Helsinki University of Technology) and University of Oulu, Finland, the Alcatel-Lucent Chair at SUPÉLEC in France, and University of Toronto in Canada. His fields of interest span the broad area of scalable wireless communication and networking, with emphasis on relay techniques, multiuser techniques, cognitive radio, interference alignment, and optimization theory. He has over 40 publications in major technical journals and conferences. He served as a Technical Program Chair and Technical Program Committee member of several major IEEE conferences.