Blind adaptive space-time receiving and transmitting diversities for multiuser DS-CDMA systems

Blind adaptive space-time processing techniques are developed for both uplink reception and downlink transmission in multiuser TDD DS-CDMA systems to overcome multipath fading effects and multiple access interference. The system consists of a space-time array, a decorrelator, and a weight-adapter. For uplink reception, a hybrid combination of the constant modulus algorithm and decision-directed algorithm approach is employed for blind adaptation. For multi-input-multi-output channel estimation, minimum mean squared error estimation is made using re-spread sequences of the decision symbols as references. For downlink multiuser transmission, the generalized zero-forcing approach is developed for pre-equalization and pre-interference cancellation