Constructing optimal space-time codes over various signal constellations

For any space-time code having a fixed, finite signal constellation, there is a tradeoff between the transmission rate and the transmit diversity gain achieved by the code. For any number of transmit antennas, a unified construction of space-time codes is provided, for a class of signal constellations that includes pulse-amplitude-modulation (PAM), quadrature-amplitude-modulation (QAM) and 2^K-ary phase-shift-keying (PSK) as special cases. The construction is optimal as measured by the rate-diversity tradeoff.