A network of Kalman filters based detector for joint MAI and ISI suppression in asynchronous DS-CDMA systems

The paper deals with a new joint intersymbol and multiple-access interference suppression algorithm based on a network of Kalman filters. The application of the Kalman filter as a multiuser detector (MUD) in the case of a non Gaussian state noise (which is related to the transmitted symbols of the users in our case) is not optimal. Our approach is based on the approximation of the a posteriori probability density function (PDF) of the symbol sequences of the users by a weighted sum of Gaussians, where each Gaussian term's parameters are adjusted using one Kalman filter. The resulting detector is structured into a network of Kalman filters. The proposed algorithm allows a significant performances improvement compared to the Kalman detector and the RAKE receiver.