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Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. Optimal transmit strategies in MIMO ricean channels with MMSE receiver
 IEEE Vehicular Technology Society VTS: IEEE 60th Vehicular Technology Conference, VTC 2004 Fall. Proceedings. Vol.5 : Wireless technologies for global security ; 26  29 September 2004, Los Angeles Airport Marriott Hotel, Los Angeles, California, USA Piscataway, NJ: IEEE Operations Center, 2004 ISBN: 0780385217 ISBN: 0780385225 pp.37873791 
 Vehicular Technology Conference (VTC) <60, 2004, Los Angeles/Calif.> 

 English 
 Conference Paper 
 Fraunhofer HHI () 
Abstract
In this work, we study a MIMO system with MMSE receiver in a flatfading environment. We assume that the receiver has perfect CSI and the transmitter knows only the mean channel matrix either by feedback or channel estimation. First, we derive the properties of the average normalized MSE and its dependence on the singular values of the mean component. Next, we show that the optimal transmit strategy is to transmit into direction of the eigenvectors of the squared mean component. In addition to this, we characterize the optimal power allocation using the necessary and sufficient optimality conditions. Furthermore, the optimal strategy for small SNR values is to perform beamforming, i.e. to transmit only in direction of the largest mean matrix eigenvalue.