Closed-loop four-antenna transmission schemes based on EO-STBCs with partial feedback

We present several close-loop four-antenna transmission schemes based on the extended orthogonal space-time block codes (EO-STBCs). Among the proposed schemes, power allocation and phase rotation are taken into account as the partial feedback information to maximize the Frobenius norm of the equivalent channel matrix so as to increase the antenna array gain. We show that the optimal scheme employing both power allocation and phase rotation could achieve the best antenna array gain and full transmit diversity. At the cost of performance loss, some sub-optimal scenarios are provided by using decreased partial feedback information, and their performance loss is analyzed in details compared with the proposed optimum one. Lastly, we demonstrate our analysis by simulation. The achieved results could provide a theoretical reference for the practical design of the close-loop 4 antenna transmission schemes.