Iterative phase recovery method of turbo-coded 16QAM based on soft symbol to bit mapping

We propose a new binary turbo-coded system with phase recovery in I6-QAM modulation. In this system, based on the soft symbol to bit mapping technique, we first get the soft bit information from the received signals and then send them to the binary turbo decoders. The soft outputs of the turbo decoders are recombined and feedback to phase recovery part to perform iterative maximum likelihood (ML) estimation of the carrier phase error. Next the received signals whose phase errors are partially corrected by using the phase estimation and then mapped to bit information for the next decoding iteration. Moreover, the parallel decoding implementation of the turbo coded 16QAM system is given based on the soft symbol to bit conversion. In addition, performance of phase recovery algorithm in different conditions and the corresponding bit error rate (BER) of the whole system are also presented.