Efficient implementation of the sum-product algorithm for quantized decoding of LDPC codes

Sheng Tong, Peng Wang, Dan Wang, Xin Mei Wang

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


An efficient implementation of the, Sum-Product algorithm (SPA) in the log-likelihood ratio (LLR) domain is presented in [1]. We modify a formula in [1] such that SPA can be implemented by using two small look-up tables. With this modification, all the calculations involved in this implementation involve only additions, subtractions, comparisons and table looking-ups, which leads to low computation complexity and facility in hardware implementation. Based on this modified implementation, various quantization schemes of SPA for decoding low-density parity-check (LDPC) codes are investigated. And the issues related to quantization, such as clipping levels and variables quantization, are also investigated. Simulation results show that the performance of the uniform quantization scheme is very close to that of the non-quantization over the AWGN channel. Moreover, it can obtain the same performance as that of non-quantization at high SNRs.

Original languageEnglish
Pages (from-to)709-713+735
JournalXi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University
Issue number5
StatePublished - Oct 2004
Externally publishedYes


  • Forward/backward algorithm
  • Iterative decoding
  • LDPC codes
  • Parallel implementation
  • Sum-Product algorithm


Dive into the research topics of 'Efficient implementation of the sum-product algorithm for quantized decoding of LDPC codes'. Together they form a unique fingerprint.

Cite this