A nonbinary LDPC-coded product distribution matching probabilistic shaping scheme for high order modulation

Abstract

In this paper, a non-binary low-density parity-check (LDPC)-coded low complexity product distribution matching (PDM) probabilistic shaping (PS) scheme for high-order modulation is proposed. Compared with conventional non-binary LDPC-coded regular quadrature amplitude modulation (QAM) schemes, the proposed non-binary LDPC-coded low complexity PDM-PS QAM scheme can obtain shaping gain, as evidenced through theoretical average mutual information and simulated error performance analyses. When the spectral efficiency is 4.5 bits/s/Hz, compared with the regular 64QAM system, the proposed 64QAM PDM-PS system can obtain 0.26 dB theoretical energy gain, while its simulated error performance is 0.30 dB. When the spectral efficiency is 6.0 bits/s/Hz, compared with the regular 256QAM system, the proposed 256QAM PDM-PS system can obtain 0.73 dB theoretical energy gain, while its simulated error performance is 0.93 dB. Compared with the conventional non-binary LDPC-coded PS QAM scheme, the proposed non-binary LDPC-coded PDM-PS QAM scheme can reduce the computational complexity by 33.1% and 49.7% under 64QAM and 256QAM, respectively, with acceptable error performance loss. The information-theoretic and error performance analyses both indicate the effectiveness and reliability of the proposed scheme.