Faculty of Engineering and Natural Sciences
Optimum Transmit Strategies for MIMO Networks with Partial CSI
Alkan Soysal, University of Maryland, College Park, MD
Multi-input multi-output (MIMO) systems promise considerable amount of rate increase with respect to single antenna systems. However the amount of this rate increase depends on the availability and the quality of the channel state information (CSI) at the receiver and the transmitter, which may not be practical to obtain perfectly. In this talk, we will consider single-user and multi-user resource allocation problems in MIMO systems, where the receiver side has the perfect CSI, and the transmitter side has partial CSI, which is in the form of long-term statistical information of the channel. We will begin with finding the optimum transmit directions of all users in such a medium, and determine the set of conditions under which beamforming is the optimal transmit strategy. We will present provably convergent algorithms that find the optimum power allocation over the antennas of each user. Next, we will focus on asymptotically large systems, and show that beamforming is always optimal. Finally, we will generalize our results to even more practical systems where the receiver-side CSI is not perfect and subject to channel estimation errors, and mention how these rates can be achieved with an adaptive MQAM scheme.
Alkan Soysal received the B.S. degree in electrical and electronics engineering from Middle East Technical University, Ankara, Turkey in 2002, and the M.S. degree in electrical and computer engineering from the University of Maryland, College Park, MD in 2006. He is currently working toward the Ph.D. degree in the Department of Electrical and Computer Engineering, University of Maryland, College Park with an expected graduation date of December 2007. His research interests include wireless communication theory and information theory with particular focus on resource allocation problems in practical MIMO networks.
December 14, 2007, 13:10, FENS L062