Space-time block coding for frequency-selective and time-varying channels

In this work, we present a new space-time block code for time- and frequency-selective (doubly-selective) channels. It can be interpreted as the extension of the Alamouti code to doubly-selective channels, and relies on a joint time-frequency reversal of the transmitted sequences. Under certain channel conditions, the proposed space-time block code belongs to the class that achieves full spatial, delay, and Doppler diversity using a maximum likelihood (ML) receiver, as well as a linear zero-forcing (LZF) or linear minimum mean-squared error (LMMSE) receiver. For realistic doubly-selective channels, a real-valued linear data model is presented, for which different receiver structures can be developed.