Vector groupwise interference cancellation in multi-rate DS-CDMA systems

A concatenated receiver structure is proposed, where an antenna array is used to form a simple spatial filter which provides protection against fast fading and spatial white interference and noise. Subsequently, a multiuser detector (MUD) is applied, which cancels the residual interference from the dominant high bit rate users. Low bit rate users are not considered in the MUD. A decision directed MUD is implemented, where a new adaptive scheme for reducing the cost of wrong interference estimates is proposed. Simulation results indicate that such a structure provides a significant gain of 69% in throughput when implemented for UMTS