Joint Decoding of LDPC Code and Phase Factors for OFDM Systems With PTS PAPR Reduction

In this paper, we investigate a low-density parity-check (LDPC)-coded orthogonal frequency-division multiplexing (OFDM) system with a peak-to-average power ratio (PAPR) reduction using the partial transmit sequence (PTS), which does not transmit PTS side information about the phase factors. We view the PTS processing as a stage of coding and call the resulted code of LDPC coding and PTS processing a concatenated LDPC-PTS code. Then, we derive the parity-check matrix of the concatenated LDPC-PTS code. With the parity-check matrix, the LDPC code and phase factors can be jointly decoded using belief propagation algorithms. Neither transmission of PTS side information (phase factors) nor phase factor estimation before decoding is required by the proposed scheme. Simulation results show that the proposed joint decoding provides nearly perfect phase factor recovery and LDPC decoding for a small number of PTS partitions.