A multi-slot method to estimate fast-varying channels in TD-CDMA systems

In mobile communications, the multipath radio channel is characterized by fast-varying faded amplitudes and slowly-varying delays. These different varying rates can be exploited by estimating the temporal subspace of the channel through a multi-slot averaging. This paper proves that the temporal subspace basis can be calculated with any accuracy (provided that the averaging memory is large enough), so that the mean square error (MSE) on the channel response depends only on the number of fast-varying parameters. The method shows promising benefits in the channel estimation for time slotted system such as the third generation TD-CDMA standards (TDD-UTRA [1] or TD-SCDMA [2]).