Abstract: The design criteria of space-time code(STC) for quasi-static fading channels, fast fading channels, and the time-varying fading channels are investigated. The first-event error probability of STC is evaluated, and a new hybrid design criterion of space-time code for time-varying fading channels is proposed based on that probability. Some new quadrature phase-shift keying (QPSK) STCs designed by the new criterion are proved, by simulation results, to be better than the known codes.

Key words: space-time code, first-event error probability, time-varying fading channels