In this paper, we present a new space-time-frequency coded orthogonal frequency-division multiplexing (OFDM) scheme that achieves high diversity gain through frequency-selective multipath fading channels with L taps. The proposed serial concatenated scheme combines an inner super-orthogonal space-time-frequency trellis code (SOSTFTC) with an outer punctured convolutional code (PCC) that provides additional coding and diversity gain, so that the overall diversity of the system becomes G_d = N_r×min{L_gd_(free), N_tL} where N_t and N_r are the number of transmit and receive antennas, respectively, L_g is the build-in space-frequency diversity of the SOSTFTC, and d_(free) is the outer code's minimum Hamming distance. The bit error rate (BER) for an example concatenated code employing inner 16-state QPSK SOSTFTC was evaluated by computer simulations and it is shown that significant error performance improvement is obtained.
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