Hardware Architecture of Layered Decoders for PLDPC-Hadamard Codes

Protograph-based low-density parity-check Hadamard codes (PLDPC-HCs) are a new type of ultimate-Shannon-limit-approaching codes. In this paper, we propose a hardware architecture for the PLDPC-HC layered decoders. The decoders consist mainly of random address memories, Hadamard sub-decoders and control logics. Two types of pipelined structures are presented and the latency and throughput of these two structures are derived. Implementation of the decoder design on an FPGA board shows that a throughput of $1.48$ Gbps is achieved with a bit error rate (BER) of $10^{-5}$ at around $E_b/N_0 = - 0.40$ dB. The decoder can also achieve the same BER at $E_b/N_0 = - 1.14$ dB with a reduced throughput of $0.20$ Gbps.