A semi-blind LMMSE multiuser detector for DS-CDMA using a subspace noise estimator

In this paper a semi-blind LMMSE multiuser detector is given for use in multipath DS-CDMA communication systems. The detector uses a subspace-based method of estimating channel noise. Due to its computational simplicity, the detector is suitable for use in either the downlink or the uplink of a DS-CDMA system. This detector gives superior performance over both the conventional single user detector and the LMMSE detector with no knowledge of the noise power.