Multislot estimation of fast-varying space-time channels in TD-CDMA systems

We propose a subspace method to estimate the time-varying space-time channel by taking into account the different rates of variation between delays/directions of arrival (slowly-varying) and faded amplitudes (fast-varying) of the multipath propagation. The stationarity of angles and delays across several time-slots is exploited to perform an unstructured estimation that avoids the explicit computation of the path parameters. Numerical analysis for a TD-CDMA system shows that the asymptotic performance is reached with a reasonable number of slots.