Adaptive filter theory (3rd ed.)
Adaptive filter theory (3rd ed.)
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Blind multiuser detection: a subspace approach
IEEE Transactions on Information Theory
Spectral efficiency of CDMA with random spreading
IEEE Transactions on Information Theory
Linear multiuser receivers: effective interference, effective bandwidth and user capacity
IEEE Transactions on Information Theory
IEEE Transactions on Information Theory
IEEE Transactions on Information Theory
MMSE detection in asynchronous CDMA systems: an equivalence result
IEEE Transactions on Information Theory
Blind adaptive multiuser detection
IEEE Transactions on Information Theory
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The Lebesgue spectrum filter (LSF), a finite impulse response (FIR) filter whose coefficients decay exponentially with a negative factor r := √3 - 2, is shown to be effective preprocessing for spreading code in asynchronous code-division multiple-access (CDMA) systems. The LSF has only been studied independently from the well-known minimum mean-square error (MMSE) filter, an optimal FIR filter in the mean-square error sense. In this paper, we propose an efficient structure, employing the LSF at the transmitter and the MMSE filter at the receiver, for asynchronous CDMA systems. We employ a spreading code preprocessed by the LSF (referred to as LSF-code), and the LSF-code supplies a "best" initial estimate (among the ones obtained without any a priori information) to an adaptive algorithm for the MMSE filter, leading to significant reduction of iterations in adaptation. This is verified by computer simulations. Also we investigate the link between the LSF and the MMSE filter by examining their autocorrelation properties.