DocumentCode :
810229
Title :
Generalized Correlation Decomposition-Based Blind Channel Estimation in DS-CDMA Systems With Unknown Wide-Sense Stationary Noise
Author :
Zarifi, Keyvan ; Gershman, Alex B.
Author_Institution :
INRS-EMT, Univ. du Quebec & Concordia Univ., Montreal, QC
Volume :
56
Issue :
11
fYear :
2008
Firstpage :
5605
Lastpage :
5617
Abstract :
A new blind subspace-based channel estimation technique is proposed for direct-sequence code-division multiple access (DS-CDMA) systems operating in the presence of unknown wide-sense stationary noise. Unlike most of the blind techniques developed for unknown correlated noise environments so far, the proposed algorithm is applicable to an arbitrary symbol constellation and does not require any auxiliary antennas at the receiver or any prior knowledge of the interfering user spreading codes. Our approach exploits the centro-Hermitian property of the unknown noise covariance matrix and makes use of the generalized correlation decomposition (GCD) to obtain an accurate estimate of the noise subspace and, consequently, of the user-of- interest channel vector. We also obtain optimal values of the GCD weighting matrices which maximally preserve the orthogonality of the estimated noise subspace to the actual signal subspace in the high signal-to-noise ratio (SNR) regime. It is shown that such an optimal choice of the weighting matrices transforms GCD to an extended form of the conventional canonical correlation decomposition (CCD). Simulation results further demonstrate that if such an extended CCD-based approach is used to estimate the user-of-interest channel vector, then the estimation performance can be substantially improved as compared to earlier SVD-based blind channel estimation techniques.
Keywords :
channel estimation; code division multiple access; correlation methods; covariance matrices; matrix decomposition; spread spectrum communication; DS-CDMA system; GCD weighting matrices; arbitrary symbol constellation; blind channel estimation; conventional canonical correlation decomposition; correlated noise; direct-sequence code-division multiple access system; generalized correlation decomposition; signal-to-noise ratio; spreading codes; stationary noise; unknown noise covariance matrix; user-of-interest channel vector; Blind channel estimation; canonical correlation decomposition (CCD); generalized correlation decomposition (GCD); multiuser detection; subspace techniques;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2008.928697
Filename :
4568046
Link To Document :
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