A novel design of unitary space-time constellations

In this paper, we propose a novel method for creating constellations of unitary space-time signals for non-coherent multiple-antenna communication link, where neither the transmitter nor the receiver knows the fading coefficients. By employing a theorem for the Clarke subdifferential of the sum of the k largest singular values of the unitary matrix, we present a numerical optimization procedure for finding good constellations of unitary space-time signals and report the best constellations found by this procedure. These constellations of unitary space-time signal improve the performance significantly upon previously best known constellations.