Space-time constellations for unknown frequency-selective channels

We consider the design of space-time constellations for communication over frequency-selective fading channels where neither the transmitter nor the receiver has any channel state information. The design is based on the asymptotic union bound on error probability as design criterion and the optimization is carried out using a gradient search algorithm. Full multi-antenna multipath diversity gains are demonstrated to be achieved by the designed codes. Compared to other constellations proposed by Hochwald et al., power savings of up to 2 dB are shown to be possible.