Effects of Imperfect Blind Channel Estimation on Performance of Linear CDMA Receivers

In a code division multiple access (CDMA) system, signal detection under multipath distortion typically requires estimation of unknown channel parameters first. In such a scenario, performance of receivers highly relies on the accuracy of channel estimates. In this paper, effects of channel estimation errors on the performance of linear CDMA receivers due to finite data samples are studied when channel parameters are estimated blindly by a recently proposed covariance-matching technique. Those receivers include zero-forcing (ZF), direct matrix-inversion (DMI) minimum mean-square-error (MMSE), subspace MMSE, and RAKE receivers. Their output signal-to-interference-plus-noise ratios (SINRs) and bit-error-rates (BERs) are adopted for performance measures. Expressions for performance indicators under such an imperfect condition are derived from a perturbation perspective and verified by simulation examples.