Title :
Adding diversity to multi-user downlink beamforming by using BER constraints
Author :
Zanatta Filho, Danilo ; Féty, Luc ; Romano, Joao Marcos Travassos
Author_Institution :
State Univ. of Campinas, Campinas
Abstract :
In this work, we propose a novel structure and criterion for joint transmit diversity and multi-user downlink beamforming. The proposed structure can be seen as an extension of the purely spatial downlink beamforming and is a transformation that, for each user, transforms K real antennas into L virtual antennas, with L les K. Classical transmit diversity is then applied to these virtual antennas. We propose a design criterion to optimize the precoders in order to find the best trade-off between minimizing the interference generated towards the other users and maximizing the channel diversity for the desired user. This criterion is based on the minimization of the total transmit power subjected to a target BER constraint for each user. Applied to a multiple-antenna transmitter, the proposed technique outperforms the purely-spatial downlink beamformer by about 5 dB for a target BER of 10-2 in a simple scenario.
Keywords :
antenna arrays; array signal processing; channel coding; diversity reception; error statistics; iterative methods; multiuser channels; optimisation; precoding; radio links; transmitting antennas; BER constraints; bit error rate; channel diversity maximization; iterative algorithm; multiple-antenna transmitter; multiuser downlink beamforming; precoder optimization; transmit diversity; transmit power minimization; virtual antennas; Array signal processing; Bit error rate; Design optimization; Downlink; Interference constraints; Mobile antennas; Signal processing; Spatial filters; Transmitters; Transmitting antennas; MIMO; Minimum BER; Multi-User; Multiple antennas; Smart antennas; antenna correlation; channel correlation; downlink beamforming; transmit diversity;
Conference_Titel :
Telecommunications Symposium, 2006 International
Conference_Location :
Fortaleza, Ceara
Print_ISBN :
978-85-89748-04-9
Electronic_ISBN :
978-85-89748-04-9
DOI :
10.1109/ITS.2006.4433358