Layered Decoding for Protograph-Based Low-Density Parity-Check Hadamard Codes

In this letter, we propose a layered decoding algorithm for protograph-based low-density parity-check Hadamard codes (PLDPC-HCs), which have been shown to be ultimate-Shannon-limit approaching. Compared with the standard decoding algorithm, the layered decoding algorithm improves the convergence rate by about two times. At a bit error rate of 2.0×10
^-5
, the layered decoder using 20 decoding iterations shows a very small degradation of 0.03 dB compared with the standard decoder using 40 decoding iterations. Moreover, the layered decoder using 21 decoding iterations shows the same error performance as the standard decoder using 41 decoding iterations.