Open Access

Blind Reduced-Rank MMSE Detector for DS-CDMA Systems

EURASIP Journal on Advances in Signal Processing20032002:356983

https://doi.org/10.1155/S1110865702209087

Received: 18 March 2002

Published: 2 January 2003

Abstract

We first develop a reduced-rank minimum mean squared error (MMSE) detector for direct-sequence (DS) code division multiple access (CDMA) by forcing the linear MMSE detector to lie in a signal subspace of a reduced dimension. While a reduced-rank MMSE detector has lower complexity, it cannot outperform the full-rank MMSE detector. We then concentrate on the blind reduced-rank MMSE detector which is obtained from an estimated covariance matrix. Our analysis and simulation results show that when the desired user′s signal is in a low-dimensional subspace, there exists an optimal subspace so that the blind reduced-rank MMSE detector lying in this subspace has the best performance. By properly choosing a subsspace, we guarantee that the optimal blind reduced-rank MMSE detector is obtained. An adaptive blind reduced-rank MMSE detector, based on a subspace tracking algorithm, is developed. The adaptive blind reduced-rank MMSE detector exhibits superior steady-state performance and fast convergence speed.

Keywords

CDMA blind multiuser detection reduced-rank MMSE subspace tracking

Authors’ Affiliations

(1)
Department of Electrical and Computer Engineering, University of Minnesota
(2)
Department of Electrical and Computer Engineering, New Jersey Institute of Technology

Copyright

© Cai et al. 2002