A novel decision-directed channel estimator for OFDM systems

Existing DD estimators in OFDM systems do not appropriately reduce the influence brought by incorrect decision, and hence suffer from error propagation. In order to mitigate the error propagation in DD channel estimation, a novel DD channel estimator based on recursive linear minimum mean-square error (LMMSE) is proposed. The algorithm takes the error vector of previous channel state information (CSI) estimation as new information for the current CSI estimation, then calculates the desired correction that the new information brings to the current CSI estimation according to the orthogonality principle and corrects the current CSI estimation with this correction term, thereby the effect induced by incorrect decision can be reduced. Analysis and simulation results have shown that the performance of the proposed algorithm is much better than the conventional DD channel estimation, and close to the optimal LMMSE estimator.