Blind decoders for linear dispersion codes in downlink DS-CDMA systems

Among many proposed space-time codes, the linear dispersion (LD) space-time codes possess many coding advantages and retain a simple decoding at the same time. An LD decoder combined with a blind subspace-based multiuser detector (MUD) is studied in the downlink of a DS-CDMA system. To further improve the performance, a subspace-based sphere decoding algorithm is proposed. Finally, a decimation-combining processing is applied to the proposed subspace-based blind decoders to reduce the complexity with only slight performance loss.