Title :
Downlink beamforming for frequency division duplex systems
Author :
Hugl, Klaus ; Laurila, Juha ; Bonek, Ernst
Author_Institution :
Inst. fur Nachrichtentech. und Hochfrequenztech., Tech. Univ. Wien, Austria
fDate :
6/21/1905 12:00:00 AM
Abstract :
We propose a downlink beamforming method for an adaptive antenna system utilizing our new spatial covariance matrix transformation (SCMT). Therefore we first estimate the azimuthal power spectrum (APS) of the received uplink data for all users within the same physical channel. Afterwards we modify the APS of the user and the interference to prevent beampointing errors for the desired user and improve the nulling capabilities. Finally we construct the spatial covariance matrices at the downlink frequency and use this spatial information for antenna weight calculation. The approach is applicable for any adaptive antenna system with FDD. It outperforms direction of arrival based methods by at least 10 dB in SNIR. Applying the SCMT we approach the upper downlink limit within 4 dB in urban environments
Keywords :
adaptive antenna arrays; array signal processing; cellular radio; covariance matrices; digital simulation; interference suppression; multiuser channels; radio links; radiofrequency interference; space division multiple access; spectral analysis; SDMA; SNIR; adaptive antenna system; antenna weight calculation; azimuthal power spectrum; beampointing errors; cellular mobile communication systems; direction of arrival based methods; downlink beamforming; downlink frequency; frequency division duplex systems; interference; nulling capabilities improvement; physical channel; received uplink data; simulation environment; space division multiple access; spatial covariance matrices; spatial covariance matrix transformation; spatial information; urban environments; Adaptive arrays; Antennas and propagation; Array signal processing; Covariance matrix; Degradation; Downlink; Frequency conversion; Narrowband; Robustness; Telecommunications;
Conference_Titel :
Global Telecommunications Conference, 1999. GLOBECOM '99
Conference_Location :
Rio de Janeireo
Print_ISBN :
0-7803-5796-5
DOI :
10.1109/GLOCOM.1999.827574
