IS MULTIUSER DETECTION DEAD? INTERCARRIER INTERFERENCE SUPPRESSION IN OFDM SYSTEMS
|Organization ||UNIVERSITY OF TENNESSEE|
|Location||EBII ROOM 1230|
|Start Date ||November 16, 2007 12:30 PM|
|End Date ||November 16, 2007 1:30 PM|
Orthogonal frequency division multiplexing (OFDM) is flourishing as the fundamental signaling technique of 4G wireless communication systems. However, its transmission rate is limited by inter-carrier interference (ICI), which is caused by time selectivity of fading channels. Multiuser detection, a well-known technique to suppress interference in CDMA systems, is applied to tackle the problem of ICI. Equivalent spreading code formulation is derived based on the analogy of OFDM and CDMA systems. Technique of linear multiuser detection in CDMA systems is applied to suppress the ICI in OFDM systems. Performance of linear detectors, measured by multiuser efficiency and asymptotic multiuser efficiency, is analyzed in cases with or without channel state information. The performance gain of linear minimum mean square effort (LMMSE) filter over traditional filter (TF) in the high signal-to-noise ratio (SNR) regime is demonstrated with theoretical analysis and numerical simulation results.
Dr. Li received the BS and MS degrees in electronic engineering from Tsinghua University, Beijing, China, in 1998 and 2000, respectively, and the Ph.D. degree in electrical engineering from Princeton University, Princeton, New Jersey in 2005. From 2005 to 2007, he worked as a senior engineer at Qualcomm Inc., San Diego, CA. In 2007, he joined the EECS department of the University of Tennessee, Knoxville, TN, as an assistant professor.
His research is mainly focused on statistical signal processing, wireless communications, networking and information theory. He is also interested in the theory of random matrices. Dr. Li is the recipient of the Best Paper Award of EURASIP Journal of Wireless Communications and Networks, 2005 (together with this PhD. Advisor: Prof. H.V. Poor).