We propose an improved orthogonal frequency division multiplexing (OFDM) signal detector which uses the minimum mean-square error (MMSE) noise feedback equalization (NFE). The input bit stream is trellis-coded to form OFDM signal blocks and the maximal ratio combining (MRC) is adopted at the receiver in order to improve the performance of the detector. As a result, we obtain significantly improved detection performance compared with the conventional OFDM receivers as follows. Using the proposed MMSE-NFE in the receiver, we can obtain the performance gain of about 1.5 dB to 2 dB in symbol energy to noise power spectral density (E-s/N-O) for Doppler frequencies of f(d) = 20 and 100 Hz, respectively over the receiver with the MMSE linear equalization (LE) alone at symbol error rate (SER) of about 10(-3). With MRC and trellis coding, the performance gain of about 11 dB in E-s/N-O for f(d) = 20 and 100 Hz at SER of about 10(-3) is obtained.