Group-blind multiuser detection for uplink CDMA

The recently developed blind techniques for multiuser detection in code div ision multiple access (CDMA) systems lead to several near-far resistant ada ptive receivers for demodulating a given user's data with the prior knowled ge of only the spreading sequence of that user. In the CDMA uplink, however , typically the base station receiver has the knowledge of the spreading se quences of all the users within the cell, but not that of the users from ot her cells. In this paper, group-blind techniques are developed for multiuse r detection in such scenarios. These new techniques make use of the spreadi ng sequences and the estimated multipath channels of all known users to sup press the intracell interference, while blindly suppressing the intercell i nterference. Several forms of group-blind linear detectors are developed ba sed on different criteria. Moreover, group-blind multiuser detection in the presence of correlated noise is also considered. In this case, two receivi ng antennas are needed for channel estimation and signal separation. Simula tion results demonstrate that the proposed group-blind linear multiuser det ection techniques offer substantial performance gains over the blind linear multiuser detection methods in a CDMA uplink environment.