Direct group-blind multiuser detection for DS-CDMA systems in dispersive channels

We consider the problem of blind (i.e., without training sequence) mitigation of both intersymbol interference (LSI) and multiple-access interference (MAI) in the uplink of asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems transmitting over time-dispersive channels. The proposed method exploits the knowledge (certainly available at the base-station site) of the spreading codes belonging to a group of the active users to directly extract the detector parameters from the received data, without requiring an explicit channel identification step. Simulation results show that the proposed group-blind receiver outperforms the existing blind methods, for small to moderate values of the sample-size.