Space-Time Autocoding

Prior treatments of space-time communications in Rayleigh flat fading generally assume that channel coding covers either one fading interval - in which case there is a nonzero "outage capacity" - or multiple fading intervals - in which case there is a nonzero Shannon capacity. However, we establish conditions under which channel codes span only one fading interval and yet are arbitrarily reliable. In short, space-time signals are their own channel codes. We call this phenomenon space-time autocoding, and the accompanying capacity the space-time autocapacity.