EURASIP Journal on Applied Signal Processing
Volume 2003 (2003), Issue 11, Pages 1157-1166
doi:10.1155/S1110865703305074
Equivalence between Frequency-Domain Blind Source Separation and
Frequency-Domain Adaptive Beamforming for Convolutive Mixtures
1NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0237, Japan
2Graduate School of Information Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
Received 2 December 2002; Revised 16 March 2003
Abstract
Frequency-domain blind source separation (BSS) is shown
to be equivalent to two sets of frequency-domain adaptive
beamformers (ABFs) under certain conditions. The zero
search of the off-diagonal components in the BSS update equation
can be viewed as the minimization of the mean square error in the
ABFs. The unmixing matrix of the BSS and the filter
coefficients of the ABFs converge to the same solution
if the two source signals are ideally independent. If they are
dependent, this results in a bias for the correct unmixing filter
coefficients. Therefore, the performance of the BSS is limited to
that of the ABF if the ABF can use exact
geometric information. This understanding gives an interpretation
of BSS from a physical point of view.