Two-Dimensional Space–Time Pilot-Symbol-Assisted Demodulation for Frequency-Nonselective Rayleigh Fading Channels

A two-dimensional space–time pilot-symbol-assisted demodulation system is proposed in this paper. Since complex scattering environments can produce nontrivial space–time correlation characteristics, this paper proposes coherent demodulation by estimating the fading channel distortion using pilot observations across both space and time. The optimum interpolation filter takes in multiple signals from receiving antennas, and exploits the space–time channel correlation to produce multiple channel-estimate outputs corresponding to every antenna. The optimal channel-estimation filter, mean-square error performance, and the pairwise symbol-error probability are derived for realistic scattering models to characterize the system performance. A design criterion is proposed for the pilot-symbol spacing and the filter length. Since the filter is a function of the statistical description of the channel, we investigate whether this statistical description and the resulting optimal filters can be estimated simply from the pilot observations.