Performance analysis of Alamouti scheme with joint imperfect transmit antennas selection and power allocation over Rayleigh fading channels

Paper takes the presence of the erroneous channel state information (CSI) into consideration. A three transmit antennas and one receive antenna Alamouti space-time scheme system {3,2; 1} with transmit antennas selection (TAS) is investigated. We assume that channel is an independent and flat Rayleigh fading channel and the system employs Binary Phase-Shift Keying (BPSK) modulation. Considering a solution over order statistic characteristic of the selective channel with CSI feedback error at the transmitter side, three kinds of possible TAS subsets (1,2), (1,3) and (2,3) for {3,2; 1} system are proposed. Combination of transmit power allocation technique and TAS technique, the three accurate analytical expressions of bit-error rate (BER) have been derived. The analysis results show that when the error is existed in CSI we ought to try to choose the subset consisting of largest ordinal number as transmit in a practical system. The numerical results also show that appropriate power allocation for transmit antennas selected can effectively enhance system bit error performance, when the factor k is large enough, such as k≥10, thus the BER performance of subset (1,3) is consistent with (2,3).