On construction of shannon capacity-approaching low complexity Polar-LDGM codes

Considering the problems of low convergence performance of Polar codes and high error floor of low density generator matrix (LDGM) codes, a serially-concatenated Polar-LDGM Code, which regards polar codes as external codes and LDGM codes as inner codes, was proposed on the premise of keeping the low encoding and decoding complexity of the both codes to approach the Shannon capacity of binary-input additive white Gaussian noise (BI-AWGN) channels. By the simulations for the proposed encoding and decoding system, the near-optimal combination of the inner coding rate and the outer coding rate and the near-optimal column weight of inner codes were obtained. The simulation results showed that the proposed scheme achieved a good bit error rate (BER) performance without the high error problem while keeping the low complexity.