Trellis-coded OFDM signal detection with maximal ratio combining and combined equalization and trellis decoding

Abstract

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.