An area-efficient relaxed half-stochastic decoding architecture for nonbinary LDPC codes

Xin Ru Lee, Chih Wen Yang, Chih-Lung Chen, Hsie-Chia Chang, Chen-Yi Lee

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


This brief presents an area-efficient relaxed half-stochastic nonbinary low-density parity-check (NB-LDPC) decoder. A novel decoding algorithm, namely, cumulative tracking forecast memory with concealing channel values (CTFM-CC) is proposed to reduce algorithm complexity and maintain bit-error-rate performance as well. Furthermore, the hardware complexity of variable node units (VNUs) is reduced through a truncated architecture, which only keeps the most reliable n probability density functions. To deal with the sum-product-algorithm-to-stochastic conversion of VNU, a dynamic random number generation method, which is used for sampling a stochastic symbol, is also proposed. With these features, a (168, 84) regular-(2,4) NB-LDPC code over GF(16) decoder is implemented in a 90-nm process. According to the results of postlayout simulation, this decoder can deliver a throughput of 1.13 Gb/s with a hardware efficiency of 0.90 Mb/s/K-gate at 286 MHz. Compared to related rate-1/2 NB-LDPC decoders, the proposed decoder achieves the highest hardware efficiency with similar error-correcting capability.

Original languageEnglish
Article number6949651
Pages (from-to)301-305
Number of pages5
JournalIEEE Transactions on Circuits and Systems I: Regular Papers
Issue number3
StatePublished - 1 Mar 2015


  • RHS algorithm
  • nonbinary LDPC codes
  • stochastic decoding


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