Transmit-antennae space-time block coding for generalized OFDM in the presence of unknown multipath

Transmit antenna diversity has been exploited recently to develop high-perf ormance space-time coders and simple maximum-likelihood decoders for transm issions over flat fading channels. Relying on block preceding, this paper d evelops generalized space-time coded multicarrier transceivers appropriate for wireless propagation over frequency-selective multipath channels, Multi carrier preceding maps the frequency-selective channel into a set of flat f ading subchannels, whereas space-time encoding/decoding facilitates equaliz ation and achieves performance gains by exploiting the diversity available with multiple transmit antennas, When channel state information is unknown at the receiver, it is acquired blindly based on a deterministic variant of the constant-modulus algorithm that exploits the structure of space-time b lock codes, To benchmark performance, the Cramer-Rao bound of channel estim ates is also derived, System performance is evaluated both analytically and with simulations.