Construction of Unitary Space-Time constellations in the interleaving sight

Unitary space-time modulation (USTM) is ideally suited for rapid fading scenarios, where neither the transmitter nor the receiver have the channel state information (CSI). However, it has received limited attention compared with the space-time coding schemes that need CSI. An important reason for that is USTM needs too large calculation amount when meeting with a large size constellation. We propose a size-reduced method for unitary space-time constellations in the sight of interleaving. Resorting to the UST (Unitary Space-Time) symbol-wise interleaving, we give a pseudo-random fading effect to the transmitted signals for the receiver to meet the channel requirement in theory. Simulation results show that compared with existing almost unachievable schemes, our method can greatly reduce the complexity of calculation only with a slight penalty in theory.