Simplified iterative detector and in serial-concatenated coded and pre-transformed systems

A simplified iterative detector and decoder (IDD) through pre-hard-decision (preHD) is proposed in the serial-concatenated coded and pre-transformed single-carrier system over flat Rayleigh fading channel. For the first iteration, the preHD is done by linear least squares (LS) or minimum mean-squared error (MMSE) detection, and a Chase-like symbol reliability calculation method is designed to select the preHD symbols. For the following iterations, the symbol soft information from SISO decoder is used for preHD. It is shown that the complexity of combined preHD and detection declines exponentially with the number of preHD symbols. Moreover, the performance degradation of simplified IDD is marginal when the pre-transformation size is large and the number of preHD symbols is small.