[CPCC] TALK: Collaborative Spectrum Sensing for Cognitive Radio Systems

[Ender Ayanoglu]

         Collaborative Spectrum Sensing for Cognitive Radio Systems

                           Prof. Visa Koivunen
                    Helsinki University of Technology


                          EECS Special Seminar
                           Friday, October 31
                                2:00 PM
                            Calit2 Room 3008

                                 ABSTRACT

In this work we propose an energy efficient collaborative spectrum
sensing approach for cognitive radio systems. We extend an existing
statistical hypothesis test for the presence of cyclostationarity to
multiple cyclic frequencies and establish its asymptotic
distributions. In addition, robust nonparametric detectors as well as
sequential detectors are derived and their statistical properties
established. We propose collaborative test statistics for the fusion
of local test statistics of the secondary users. A censoring technique
in which only informative test statistics are transmitted to the
fusion center (FC) during the collaborative detection is proposed for
improving energy efficiency in mobile applications.  A technique for
numerical approximation of the asymptotic distribution of the censored
FC test statistic is proposed. The proposed tests are nonparametric in
the sense that no assumptions on data or noise distributions are
required. In addition, the tests allow dichotomizing between the
desired signal and interference. Simulation experiments showing the
benefits of the proposed cyclostationary approach compared to energy
detection, the importance of collaboration. The simulation examples
focus on detecting OFDM based primary user signals because it is the
modulation scheme of choice in LTE, DVB-T/H, WLAN, WiMAX as well as
IMT-A.

                          SPEAKER'S BIOGRAPHY

Visa Koivunen (Senior Member, IEEE) received his D.Sc. (Tech) degree
with honors from the University of Oulu, Dept. of Electrical
Engineering. He received the primus doctor (best graduate) award among
the doctoral graduates in years 1989-1994. From 1992 to 1995 he was a
visiting researcher at the University of Pennsylvania, Philadelphia,
USA. Year 1996 he held a faculty position at the Department of
Electrical Engineering, University of Oulu. From August 1997 to August
1999 he was an Associate Professor at the Signal Processing
Labroratory, Tampere University of Technology. Since 1999 he has been
a Professor of Signal Processing at the Department of Electrical and
Communications Engineering, Helsinki University of Technology (HUT),
Finland. He is one of the Principal Investigators in SMARAD (Smart
Radios and Wireless Systems) Center of Excellence in Radio and
Communications Engineering nominated by the Academy of Finland.  He
has been also adjunct full professor at the University of
Pennsylvania, Philadelphia, USA. During his sabbatical leave in
2006-2007 he was Nokia Visiting Fellow at Nokia Research Center as
well as visiting professor at Princeton University.

Dr. Koivunen's research interest include statistical, communications
and sensor array signal processing. He has published more than 250
papers in international scientific conferences and journals. He
co-authored the papers receiving the best paper award in IEEE PIMRC
2005, EUSIPCO 2006 and EuCAP 2006. He has been awarded the IEEE Signal
Processing Society best paper award for the year 2007 (co-authored
with J. Eriksson). He served as an associate editor for IEEE Signal
Processing Letters. He is a member of the editorial board for the
Signal Processing journal and Journal of Wireless Communication and
Networking. He is also a member of the IEEE Signal Processing for
Communication Technical Committee (SPCOM-TC). He was the general chair
of the IEEE SPAWC (Signal Processing Advances in Wireless
Communication) 2007 conference in Helsinki, June 2007.

Host: A. Lee Swindlehurst
Directions: www.uci.edu/campusmaps.php