Subspace-based estimation of frequency-selective channels for space-time block precoded transmissions

Space time coding has been by now well documented as an attractive means of achieving high data rate transmissions with high quality of service, provided that the underlying channels can be accounted for. We propose in this paper a (semi-) blind channel estimation algorithm that is suitable for space time (ST) block precoded transmissions over frequency-selective channels. We show that multi-channel identifiability is guaranteed up to only one scalar ambiguity regardless of channel zero locations. Simulation results illustrate that the proposed algorithm is capable of tracking slow channel variations.