On the Stability Region of Cognitive Radio Systems with Imperfect Sensing

Dr. Marian Codreanu

Centre for Wireless Communications, University of Oulu, Finland

Abstract:

The talk will address the stability property of a cognitive radio system comprised of a set of source-destination pairs having different priorities. In particular, we focus attention on the effect of imperfect sensing on the stability region of the system, which has been overlooked in most of related previous work. The adopted cognitive access protocol allows the secondary user not only to exploit the idle slots of the primary user but also to transmit along with the primary user with some probability. This is aimed at achieving the full utilization of the shared channel with capture, i.e., a transmission can be correctly decoded at the destination, even in the presence of other transmissions, if the received signal-to-interference-plus-noise ratio (SINR) exceeds a certain threshold for successful decoding. The abolition of strong primacy, however, requires the secondary user to properly regulate its multi-access probability in order not to impede the primary user’s stability guarantee. To this end, the maximum stability region of the system is characterized which describes the theoretical limit on rates that can be pushed into the system while maintaining the queues stable. Interestingly, we found that even with non-zero sensing error rates, there exists a condition for which we can achieve the identical stability region that is achieved with perfect sensing. For the case when the specified condition does not hold, we precisely quantify the loss due to the imperfect sensing in terms of the size of the stability region.

The talk is based on the following paper (please find the manuscript attached): J. Jeon, M. Codreanu, M. Latva-aho, and A. Ephremides, "The Stability Property of Cognitive Radio Systems with Imperfect Sensing," IEEE Journal on Selected Areas in Communications. Accepted for publication, March 2014.

Biography:

Marian Codreanu received the M.S. degree from the University Politehnica of Bucharest, Romania, in 1998, and the Ph.D. degree from University of Oulu, Finland, in 2007. From 1998 to 2002 he was Teaching Assistant at the Telecommunications Department in University Politehnica of Bucharest. In 2002 he joined the Centre for Wireless Communications at University of Oulu where he is currently an Adjunct Professor. In 2008 he was a visiting postdoctoral researcher the University of Maryland, College Park, USA. His research interests include mathematical optimization, compressed sensing, information theory, and signal processing for wireless communication systems and networks.

Dr. Codreanu received the best doctoral thesis prize within the area of all technical sciences in Finland in 2007. In 2013 he was awarded an Academy Research Fellow position by the Academy of Finland. He was a co-founder and Co-Chair of the Technical Program Committee (TPC) of the First Nordic Workshop on Cross-Layer Optimization in Wireless Networks in 2010, and Co-Chair of the TPC of the Second & Fourth Nordic Workshop on System and Network Optimization for Wireless (SNOW 2011 & 2013). Currently he is serving as Vice Chair of the IEEE Finland Communications and Information Theory Joint Societies Chapter (2011 - Present).