A novel space-time pre-multiuser downlink transmission scheme suitable for TDD-CDMA systems

The conventional downlink selective transmission method is extended from the space domain to the space-time domain. Based on the cascade and joint processing in space-time domain, a so-called temporal beamformer and a space-time beamformer are presented. Then a novel downlink selective transmission scheme suitable for TDD-CDMA systems is proposed. The theoretical analysis and computer simulations demonstrate that the interference canceling performance of our approach is superior to that of the conventional spatial beamformer by sufficiently utilizing the space-time signature of mobile users. The proposed space-time joint method is superior to the space-time cascade method in terms of the interference canceling performance.