Orthogonal space-time block codes for analog channel feedback

In this paper, we propose to use complex orthogonal space-time block coding (COSTBC) in analog transmission with application to channel feedback. We prove that an equivalent complex orthogonal channel can be generated by COSTBC and then the matched filter bounds on the signal-to-noise ratio via multiple-input multiple-output channels are achieved by maximal ratio combining (MRC). Simulation shows that COSTBC-MRC analog schemes outperforms spatial-multiplexing oriented analog schemes and uncoded random vector quantization schemes with respect to mean-squared errors (MSE).