Downlink performance of Alamouti space-time transmission in practical distributed antenna systems

Motivated by realistic applications, we focus on the downlink performance of a practical distributed antenna system (DAS) in this paper. The so-called practical DAS represents a multi-cell DAS with individual transmit power constraint for each antenna element and only the large-scale channel state information (CSI) known at the transmitters. In order to give consideration to both utility of transmit power and suppression of inter-cell interference, a simple Alamouti space-time transmission (ASTT) scheme is proposed. Accordingly, we derive a closed-form expression for the ergodic achievable rate offered by ASTT so as to evaluate quantitatively the performance of ASTT. It is demonstrated that ASTT is preferable to the existing blanket transmission (BT) scheme and single transmit selection (STS) scheme under low and moderate SNR conditions.