Frequency-domain Channel Frequency Response Estimation for Space-Time Coded MIMO Systems

Frequency-domain equalization (FDE) is an effective technique to mitigate the distortion induced by long-spanning inter-symbol interference, but the receiver requires to estimate the channel information. In this paper, we present a training-based frequency-domain channel frequency response (CFR) estimation scheme, which is hardware efficient when integrating with FDE for space-time (ST) coded multiple-input multiple-output (MIMO) transmissions over frequency-selective fading channels. In this proposed scheme, training sequences are ST block encoded at the transmitter. Similar to when performing FDE, the training sequences are processed after the FFT operation to obtain the CFR. A thorough analysis of the CFR estimation mean square error (MSE) is provided based on both the least squares (LS) and minimum MSE (MMSE) criteria, with the transmit power constraint and the optimal choices of training signals being taken into account. Finally, we demonstrate that when the number of transmit antennas is equal to 2, this CFR estimation could be implemented recursively by means of certain adaptive algorithms. Simulation results are presented to demonstrate the effectiveness of our proposed scheme in joint with FDE in multipath fading channels.