A toeplitz displacement method for blind multipath estimation for long code DS/CDMA signals

The problem of blind channel identification for direct-sequence/code-divisi on multiple-access (DS/CDMA) multiuser systems is explored. For wideband DS /CDMA signals, multipath distortion is well modeled by a finite-impulse res ponse filter. In this work, a blind channel identification technique based on second-order statistics is investigated, The method exploits knowledge o f the spreading code of the user of interest via matched filtering, as well as properties of spreading codes, The current scheme focuses on a method a ppropriate for randomized long sequence DS/CDMA. This access scheme poses s pecial challenges as the spreading codes are time varying. An analytical ap proximation of the mean-squared error is derived using perturbation techniq ues. The performance of the algorithm is studied via simulation and through the mean-squared error approximation, which is observed to be tight.