Enhanced CDMA Transmission with Multiple Antennas and Joint Power Control*

We consider downlink transmission at high data rates in a multi-cellular code-division multiple-access (CDMA) network where signals are directed to a mobile station (MS) from antennas located at the same or different base stations (BSs). All antennas use different pilots and transmit data to individual MSs with specified powers when selected to do so. Two sources of error are found to degrade channel identification and performance: channel noise and channel variation due to the power control delay. First, we introduce a modified spatio-temporal array-receiver (STAR) that uses both the pilot and the data signals to reduce the channel identification error. Second, we formulate a power control algorithm for the signal powers transmitted by the participating antennas based on predicting the channel response variations over the power control interval. Significant performance gains are found to result from use of the techniques independently and collectively.