Design of Parallelly Concatenated Spatially Coupled RA Codes

In this paper, parallelly concatenated spatially coupled RA (PC-SCRA) codes was presented based on spatially coupled RA (SCRA) codes with the advantages of simple coding structure, threshold saturation and low decoding complexity. When encoding, the same message bits are respectively encoded by two same SCRA codes to obtain respective check bits. During transmission, the message bits and the obtained parity bits are merged into one codeword for transmission. Besides, density evolution algorithm was proposed to compute the iterative decoding threshold of PC-SCRA code ensemble over the binary erasure channel. Simulation results show that the proposed PC-SCRA code ensemble has excellent BP threshold performance close to Shannon limit and is superior to the spatially coupled LDPC (SC-LDPC) code with same coderate, which provides a new way for construrting capacity-approaching SC-LDPC codes.