Channel estimation for MIMO systems employing single-carrier modulations with iterative frequency-domain equalization

A promising receiver structure for LST (layered space-time) MIMO (multi-input/multi-output) schemes employs SC (single-carrier) modulation and IB-DFE (iterative block decision feedback equalization) receivers. We present a channel estimation method for these schemes. The channel estimates are obtained with the help of predefined reference blocks. These reference blocks are designed to have reduced envelope fluctuations in the time domain and the corresponding frequency domain samples have constant absolute value. This allows efficient channel estimation, and also efficient power amplification. Moreover, the reference blocks associated with the different layers are transmitted simultaneously and remain orthogonal, even for severe time-dispersive channels, allowing the estimation of all channels with a single training interval.