LATEST DEVELOMENTS
Prof. Koivunen to visit WiDeS: Prof. Visa Koivunen from Helsinki University of Technology, a renowned researcher in the field of signal processing for wireless communications, will visit WiDeS on Nov. 5th and 6th. He will give a talk on MIMO radar, one of the emerging hot topics in multi-antenna systems. Abstract and speaker bio are as follows:
Performance of MIMO Radar with AngularDiversity under Swerling Scattering Models
Visa Koivunen, Helsinki Univ. of Technology
Finland
A brief overview of different MIMO radar concepts is provided. The performance of statistical MIMO (multiple-input multiple-output) radar configurations that use distributed antennas is analyzed in detail. Statistical MIMO radars exploit angular diversity to mitigate the impact of radar cross section (RCS)d fluctuations. The fluctuations can be modeled with the Swerling scattering model consisting of four different
cases with either fast or slow target RCS fluctuations.
In this paper, the performance of different statistical MIMO radar configurations is compared in the different Swerling cases. Both target detection and direction of arrival estimation tasks are considered. We derive the optimal test statistics for target detection for non-orthogonal waveforms in all the Swerling cases in single-pulse as well as multi-pulse scenarios. In the direction finding task, confidence bounds of the squared estimation error of the different configurations are compared. The comparison is done in terms of the confidence bounds as the Cramer-Rao bounds are not defined for all the cases and configurations. The pros and cons of the angular diversity and each radar configuration are pointed out in
different fluctuation scenarios. If time allows, beampattern optimization in MIMO radar will be considered as well. This is joint work with my student Tuomas Aittomäki
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. Since 1999 he has been a Professor of Signal Processing at 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. Years 2003-2007 he was also adjunct full professor at the University of Pennsylvania, Philadelphia, USA. During his sabbatical leave in 2006-2007 he was Visiting Fellow at Nokia Research Center as well as visiting fellow at Princeton University. Year 2009 he was appointed to Academy of Finland distinguished professor position until year 2014.
Dr. Koivunen's research interest include statistical, communications and sensor array signal processing. He has published about 300 papers in international scientific conferences and journals. He co-authored the several papers receiving the best papers in conferences. He has been awarded the IEEE Signal Processing Society best paper award for the year 2007 (co-authored with J. Eriksson). He is member of the IEEE SAM and SPCOM technical committees.
PostDocs and Students join WiDeS: Fall 2009 saw the entry of the first batch of PostDocs, PhD and MS students into Wides. The complete list of the new members will be put up shortly.
More information about each member can be accessed
here.
Molisch gives keynote at WPMC in Japan: Andy Molisch, Professor at USC and Head of the WiDeS group, was invited to give a keynote address at the 12th International Symposium on Wireless Personal Multimedia Communications (WPMC) in Sendai, Japan.
Prof. Molisch delivering the Keynote address at WPMC, Sendai, Japan
The talk was entitled "Multi-user MIMO and Base Station Cooperation", and had the following abstract:
"Multiple-input - multiple-output (MIMO) systems are the method of choice for increasing spectral efficiency for fourth-generation wireless communications systems such as 3GPP-LTE, Wimax, and high-throughput WiFi (IEEE 802.11n). It has been shown that for a single link, the capacity increases linearly with the number of antenna elements at transmitter and receiver. However, in a cellular setting, new effects come into play. First, multiple users are present within one cell, which enables a tradeoff between increasing the data rate for a single user vs. communicating with multiple users at the same time. The talk will discuss methods to optimize overall throughput, as well as considerations for fairness between the users, and methods for reducing feedback overhead. Secondly, interference from neighboring cells tends to limit the capacity. The talk will thus discuss base station cooperation, where multi-antenna base stations cooperate for communications with users in multiple cells, has the potential to eliminate this bottleneck and recover the full potential of MIMO communications also in a cellular setting. A discussion of propagation channel aspects relevant for multi-user MIMO and BS cooperation will round off the talk."
Molisch to participate in "Frontiers of Engineering" Symposium of NAE: The National Academy of Engineering (NAE), has selected 88 researchers to participate in the 15th Symposium on "Frontiers in Engineering" in September 2009, among them Andy Molisch from WiDeS. Below is the press release of the NAE: CREATIVE YOUNG ENGINEERS SELECTED TO PARTICIPATE IN NAE'S 2009 U.S. FRONTIERS OF ENGINEERING SYMPOSIUM WASHINGTON — Eighty-eight of the nation's brightest young engineers have been selected to take part in the National Academy of Engineering's (NAE) 15th annual U.S. Frontiers of Engineering symposium. Engineers ages 30 to 45 who are performing exceptional engineering research and technical work in a variety of disciplines will come together for the 2-1/2-day event. The participants — from industry, academia, and government — were nominated by fellow engineers or organizations and chosen from approximately 240 applicants.
WiDeS at IEEE-ICC in Dresden: One of the flagship events of the IEEE Communications Society, the IEEE International Conference on Communications (ICC) took place in Dresden, Germany, from June 14-18. WiDes was present with 3 papers: power optimization for "split-and-combine relaying"; a model for MIMO car-to-car propagation channels; and a performance analysis of antenna selection algorithms in time-variant channels. In addition, Andy Molisch from WiDeS, together with Dr. Jeff Tao (Mitsubishi Electric Research Labs) and Prof. Neelesh Metha (Indian Institute of Science) gave a well-attended tutorial on the fundamental technologies for fourth-generation wireless systems and their implementations in the most important standards - LTE, Wimax, and 802.11n.
Jussi Salmi to join WiDeS as PostDoc: Jussi Salmi, a researcher at the Helsinki University of Technology, will join the WiDeS group in the fall as PostDoc.
Jussi Salmi was born in Finland in 1981. He received his M.Sc. degree with honors from Helsinki University of Technology, Dept. of Electrical and Communications Engineering, Espoo, Finland, in 2005, and he is currently finalizing his Ph.D. degree. From 2004 to 2005, he worked as a Research Assistant at Radio Laboratory, Helsinki University of Technology. Since 2005 he has held a Researcher position at Dept. of Signal Processing and Acoustics, Helsinki University of Technology. His current research interests include measurement based MIMO channel modeling, parameter estimation, analysis of interference limited multiuser MIMO measurements as well as tensor modeling and decomposition techniques. He has authored a paper receiving the Best Student Paper Award in EUSIPCO'06, and co-authored a paper receiving the Best Paper Award in Propagation in EuCAP'06.
WiDeS IN CHINA: Andy Molisch, Professor at USC and Head of the WiDeS group, visited a number of Chinese universities, participating in the joint Tsinghua-USC workshop on "smart and green" technologies, and giving a number of presentations:
Beijing IEEE ComSoc Chapter and Beihan University (Prof. C Yang): Distributed MIMO Systems and Base Station Cooperation
Zhejiang University (Prof. H Zhang): Cross‐layer optimization of wireless collaborative ad‐hoc networks
Shanghai Jiaotong University (M Tao): Cross‐layer optimization of wireless collaborative ad‐hoc networks
Fudan University (Prof. Y Zhu): Cross‐layer optimization of wireless collaborative ad‐hoc networks
FINNISH CHANNEL MODELING RESEARCHER VISITS WIDES: Jussi Salmi, researcher at the Helsinki University of Technology, visits WiDeS on June 2nd/3rd, and gives a talk.
Abstract: Measurement-based modeling of wireless MIMO propagation channels provides realistic characterization of the physical layer for MIMO transceiver design and network planning. This talk focuses on modeling and parametric estimation of mobile MIMO radio propagation channels. Measured MIMO channels are modeled using a superposition of double-directional, specular-like propagation paths, and a stochastic process describing the diffuse scattering. A state-space modeling approach employing the Extended Kalman filter (EKF) is introduced for sequential estimation of the propagation path parameters from dynamic channel sounding measurements. Moreover, the models are formulated using tensor notation, and a novel tensor decomposition technique is presented. The proposed Sequential Unfolding SVD (SUSVD), has several applications in array signal processing, including a low rank tensor approximation similar to the one obtained using SVD for matrices.
MOLISCH RECEIVES "WIRELESS EDUCATOR OF THE YEAR" AWARD: Andy Molisch, Professor at USC and Head of the WiDeS group, has won the
Wireless Educator of the Year award for 2009 from the
Global Wireless Education Consortium. The award recognizes outstanding faculty in the area of wireless communications, and honors contributions to engineering education.
STANFORD RESEARCHER VISITS WIDES: Dr. Niki Czink, a researcher at Stanford University and well-known expert in wireless channel measurements, will visit the WIDES group on April 3rd, and will give a seminar entitled
“MIMO Interference: Don’t Forget the Spatial Structure!”
Abstract: The capacity of MIMO links under interference is already well known for spatially white channels. However, most channels show a specific spatial structure. In this talk, I will discuss the spatial properties of best-case and worst-case interference (maximizing or minimizing the mutual information), and will present results from a recent measurement campaign supporting our analytic results.
