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Home | Seminars and Symposia | Past seminars/symposia: Thursday, April 25, 2002

DTC Seminar Series

Double-Directional Channels and MIMO Systems


Andreas F. Molisch
AT&T Labs — Research

Thursday, April 25, 2002
8:30–9:30 am

402 Walter Library

Slide presentation (pdf 6.09 MB) A MIMO (multiple-input-multiple-output) wireless system has multiple antennas at both transmitter and receiver. It is possible to transmit different data streams from different antennas, and separate these streams again at the receiver. Thus, the data rate of a MIMO system can be much higher, without actually using up more spectrum. However, it is the nature of the propagation channel, especially the directions of the multipath components at transmitter and receiver, that ultimately decides the performance of MIMO systems. Thus, MIMO system design is intimately related to double-directional propagation channels. This talk will give a description of measurement methods for double-directional channels, and describe some exemplary results. Furthermore, the question how measurement results can be best transformed into efficient simulation models is addressed. We next discuss the relationship between the double-directional channels and the capacities of MIMO systems. We give an introduction to the theory of MIMO systems, and intuitive explanations for the high achievable capacities. We also present a novel method that allows the extraction of capacity distribution functions from a single measurement, saving a great deal of measurement effort. Finally, a present a reduced-complexity MIMO system, showing how the channel characteristics influence such a system will be presented.


Andreas F. Molisch received the Dipl. Ing., Dr. techn. (with highest honors), and habilitation degrees from the Technical University Vienna in 1990, 1994, and 1999, respectively. From 1991 to 2001, he was with the TU Vienna, most recently as associate professor. From 2001 to 2002, he was with AT&T Laboratories — Research as Principal Member of Technical Staff in the Wireless Systems Research Department. Since 2001, he has also been full professor for radio systems at TU Lund, Sweden. His current research interests are MIMO systems, characterization of mobile radio channels, smart antennas, and wideband systems. He is senior member of IEEE, and (co)author of two books, five book chapters, some 50 journal papers, and numerous conference contributions. His professional activities include chairman of the COST273 working group on MIMO channels, editor of the IEEE Transactions on Wireless Communications, and member of numerous Technical Program Committees.