In an orthogonal frequency division multiplexing (OFDM) system, part of bandwidth is occupied by pilot symbols for time-varying channel estimation. In order to reduce the period of the training sequence while improving bandwidth efficiency, we study new time-domain channel tracking algorithms with a modified decision feedback loop. In company with the channel tracking algorithms, some decision error detectors and error concealment methods are proposed to reduce the error probability for

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... decision error propagation. In our simulations, we compare the performance of the proposed decision error detectors and error concealment methods to show the efficiency of the proposed algorithms in time-varying channels.