OFDM channel estimation by singular value decomposition

In this report we present and analyse low-rank channel estimators for orthogonal frequency-division multiplexing (OFDM) using the frequency correlation of the channel. Low-rank approximations based on the discrete Fourier transform (DFT) have been proposed but they suffer from poor performance when the channel is not sample-spaced. We apply the theory of optimal rank-reduction to linear minimum mean-squared error (LMMSE) estimators and show that these estimators, when using a fixed design, are robust to changes in channel correlation and signal-to-noise ratio (SNR). The performance is presented in terms of uncoded symbol-error rate (SER) for a system using 16-QAM.Godkänd; 1996; 20080219 (ysko