报告题目：Wideband Spectrum Sensing for Cognitive Radio with Correlated Subband Occupancy
报告人：Prof. Benoit Champagne
Department of Electrical & Computer Engineering,
McGill University, Montréal, Canada
Abstract: In a cognitive radio (CR) system, secondary users (SU) must have the capability to detect and opportunistically use spectrum holes allocated to other, primary users (PU). In recent years, spectrum sensing has gained much importance as CR is an integral component of the IEEE 802.22 standard. Furthermore, emerging 4G wireless standards such as LTE-Advanced and IEEE 802.16m will also support CR concepts. To maximize the opportunistic throughput without interfering with existing users, including the PU or other SUs, spectrum sensing must be fast and accurate. The efficient implementation of spectrum sensing in wideband applications calls for major innovations in the areas of statistical signal processing and physical layer algorithms.
My talk will be divided into three parts. The first part will give a high-level overview of the spectrum sensing problem in CR networks. This will include a brief presentation of CR principles and terminology, formulation of the spectrum sensing problem and a brief survey of various spectrum sensing approaches that have been recently proposed in the technical literature. In particular, it will be explained that current energy detector for wideband spectrum sensing invariably employ a frequency-decoupled structure that is not suitable to exploit the correlation between subband occupancies by the PU (or other SUs). In the second part, we will present a new detector structure, called optimum linear energy detector (OLEC), which has the ability to exploit such correlation in order to improve its detection performance. To this end, we will first discuss the limitations of the optimum maximum a posteriori (MAP) detector of the wideband channel occupancy. We will then introduce the OLEC as a low-complexity, sub-optimal alternative to the MAP by considering the minimum mean-square error (MMSE) estimation of channel occupancy in the presence of subband occupancy correlation. Through analysis and simulations, we will show that the proposed detector can significantly outperform the traditional decoupled approach. In the third part, the OLEC detector will be generalized to multiple users and integrated in the spatial-spectral joint detection framework of Quan et al., to take further advantage of subband occupancy correlation in cooperative wideband spectrum sensing. In particular, it will be shown that the proposed OLEC-based cooperative detector can significantly outperform the original multi-band detector of Quan et al.
Bio: Benoit Champagne was born in Joliette (P.Q.) Canada. He received the B.Ing. degree in Engineering Physics from the Ecole Polytechnique de Montréal in 1983, the M.Sc. degree in Mathematical Physics from the Université de Montréal in 1985, and the Ph.D. degree in Electrical Engineering from the University of Toronto in 1990. From 1990 to 1999, he was an Assistant and then Associate Professor at INRS-Telecommunications, Université du Quebec, Montréal. In 1999, he joined McGill University, Montreal, where he is now a Full Professor within the Department of Electrical and Computer Engineering. He served as Associate Chair of Graduate Studies in the Department from 2004 to 2007.
Prof. Champagne’s research focuses on the development and investigation of new computational algorithms for the processing of information bearing signals by digital means. His interests span many areas of statistical signal processing, including detection and estimation, sensor array processing, adaptive filtering, and applications thereof to broadband communications. He has published several papers in these areas, including key works on time delay estimation, subspace tracking and spread sources localization. His research has been funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada, the “Fonds de recherche sur la nature et les technologies” from the Government of Quebec, as well as some major industrial sponsors, including Nortel Networks, Bell Canada, InterDigital and Zarlink (now Microsemi). He has been an Associate Editor for the IEEE Signal Processing Letters and the EURASIP Journal on Applied Signal Processing and has served on the technical and organizing committees of several international conferences. His is currently Associate Editor for the IEEE Trans. on Signal Processing and a Senior Member of IEEE.