The Kalman filter as the optimum MMSE multiuser CDMA detector

摘要

It is shown that the Kalman filter implements the exact linearMMSE filter in an asynchronous multiuser CDMA system, given anydetection delay. The Kalman filter is a finite-order recursive filter asopposed to the well-known tapped-delay line (TDL) MMSE filter, whichmust grow in length with increasing time and is therefore notpractically implementable. Our result is useful as a baseline forcomparison with other linear detectors, and may lead to adaptivedetectors with (soft) feedback