Title :
Linear space-time precoding for OFDM systems based on long-term CSI
Author :
Kusume, Katsutoshi
Author_Institution :
Wireless Solution Laboratory, DoCoMo Commun. Laboratories Eur. GmbH, Munich, Germany
Abstract :
This paper addresses the severe performance degradation for OFDM systems in case of long channel delays exceeding a guard interval. Such long delays can be seen as an interference source on one hand and also as a valuable frequency diversity source on the other hand. Instead of simply suppressing such long delays, e.g. by beamforming at transmitter, the newly proposed preceding scheme attempts to find the optimum trade-off between the interference suppression and the diversity gain for the long delays. The optimization problem is formulated exploiting only long-term channel state information instead of the instantaneous one and it is solved based on the minimum mean square error criterion with a constraint on the transmit power. Computer simulation results show that the proposed scheme outperforms the conventional beamforming scheme.
Keywords :
OFDM modulation; channel coding; delays; diversity reception; filters; interference suppression; mean square error methods; optimisation; space-time codes; telecommunication channels; OFDM systems; channel coding; channel state information; frequency diversity; interference suppression; linear space-time precoding filter; long channel delay; long-term CSI; minimum mean square error criterion; optimization; Array signal processing; Channel state information; Constraint optimization; Degradation; Delay; Diversity methods; Frequency diversity; Interference suppression; OFDM; Transmitters;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2004. PIMRC 2004. 15th IEEE International Symposium on
Print_ISBN :
0-7803-8523-3
DOI :
10.1109/PIMRC.2004.1373839