Application of iterative detector and decoder in serial concatenated coded and pre-transformed systems

The iterative detector and decoder (IDD) in the serial concatenated coded and pre-transformed system is studied in this paper. The performance of the IDD in the single-carrier system over flat fading channel and the orthogonal frequency division multiplexing (OFDM) system over frequency-selective fading channel are thoroughly evaluated. Numerical results show that in the single-carrier system, IDD with 2 to 3 iterations over flat fading channel achieves performance only about 1dB away from that over the additive white Gaussian noise (AWGN) channel. Our study also finds that for OFDM system, the IDD provides considerable performance improvement compared to the coded or pre-coded systems, even when the multipath diversity is low. IN the meanwhile, the excellent performance of IDD does not rely on the optimal design of pre-transformation matrix.