Blind and semi-blind equalization for generalized space-time precoding

This paper presents a general framework for space-time codes that encompasses a number of recently proposed schemes as special cases. The space-time codes considered are block codes that employ arbitrary redundant linear precoding of a given data sequence together with embedded training symbols, if any. The redundancy introduced by the linear precoding imposes structure on the received data that under certain conditions can be exploited for blind or semi-blind estimation of the transmitted sequence (direct approach) or a linear equalizer that recovers the sequence in a second step (indirect approach). Algorithms based on this observation are developed for the flat-fading case, and then extended to handle frequency-selective fading.