Title :
Temporal diversity assisted blind channel estimation for downlink long-code CDMA systems
Author :
Liu, Ping ; Xu, Zhengyuan
Author_Institution :
Dept. of Electr. Eng., California Univ., Riverside, CA, USA
Abstract :
In a CDMA downlink, subspace channel estimation can not be applied directly since long spreading codes destroy the rank condition of the received data covariance matrix. However, after introducing temporal diversity in the transmitted chip sequence for all users, subspace techniques can be applied to estimate channels. Detection of the desired user´s signal is then performed by a channel equalizer, cascaded with the desired user´s code despreader. The analytical channel estimation mean-square-error is derived, based on perturbation theory. Experimental comparison with our previously proposed spatial diversity method shows superior performance of the proposed scheme.
Keywords :
blind equalisers; channel estimation; code division multiple access; covariance matrices; diversity reception; mean square error methods; perturbation theory; random codes; channel equalizer; channel estimation mean-square-error; downlink long-code CDMA systems; perturbation theory; received data covariance matrix rank condition; spreading codes; temporal diversity assisted blind channel estimation; transmitted chip sequence temporal diversity; user code despreader; Blind equalizers; Channel estimation; Covariance matrix; Diversity methods; Downlink; Error correction; Error correction codes; Least squares methods; Maximum likelihood detection; Multiaccess communication;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on
Print_ISBN :
0-7803-8484-9
DOI :
10.1109/ICASSP.2004.1326986
