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On transmit diversity with imperfect channel state information

: Jorswieck, E.; Boche, H.

IEEE Signal Processing Society:
IEEE International Conference on Acoustics, Speech, and Signal Processing 2002. Proceedings. Vol.3: Signal processing for communications, sensor array and multichannel signal processing, design and implementation of signal processing systems : May 13 - 17, 2002, Renaissance Orlando Resort, Orlando, Florida, USA
Piscataway: IEEE Operations Center, 2002
ISBN: 0-7803-7402-9
International Conference on Acoustics, Speech, and Signal Processing (ICASSP) <2002, Orlando/Fla.>
Fraunhofer HHI ()
antenna arrays; array signal processing; channel capacity; covariance matrices; diversity reception; eigenvalues and eigenfunctions; radio links; radio receivers; radio transmitters; receiving antennas; transmitting antennas; transmit diversity; imperfect channel state information; multiple-input single-output system; wireless communication link; covariance matrix; eigenvalues; spatial diversity; parallel data streams; transmit antennas; receive antenna; beamforming

The optimal transmission strategy of a multiple-input single-output wireless communication link is studied. The receiver has full channel state information and the transmitter has only long-term channel state information in terms of the channel covariance matrix. A necessary and sufficient condition for the optimal eigenvalues of the transmit covariance matrix is presented. A necessary and sufficient condition for achieving capacity when transmitting in m directions is developed. The main questions regarding the system design are answered using these conditions. It is shown how the optimal number of transmit antennas can be computed to achieve full spatial diversity given the channel covariance matrix. The maximum number of required parallel data streams is computed and a transmit diversity function is defined in order to obtain a measure for the available spatial diversity.