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Electronics and Telecommunications Research Institute (한국전자통신연구원)
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Effective identification of dominant fully absorbing sets for Raptor-like LDPC codes

  • Woncheol Cho (Mobile Communication Research Division, Electronics and Telecommunications Research Institute) ;
  • Chanho Yoon (Mobile Communication Research Division, Electronics and Telecommunications Research Institute) ;
  • Kapseok Chang (Mobile Communication Research Division, Electronics and Telecommunications Research Institute) ;
  • Young-Jo Ko (Mobile Communication Research Division, Electronics and Telecommunications Research Institute)
  • Received : 2021.07.29
  • Accepted : 2022.03.22
  • Published : 2023.02.20
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Abstract

The error-rate floor of low-density parity-check (LDPC) codes is attributed to the trapping sets of their Tanner graphs. Among them, fully absorbing sets dominantly affect the error-rate performance, especially for short blocklengths. Efficient methods to identify the dominant trapping sets of LDPC codes were thoroughly researched as exhaustively searching them is NP-hard. However, the existing methods are ineffective for Raptor-like LDPC codes, which have many types of trapping sets. An effective method to identify dominant fully absorbing sets of Raptor-like LDPC codes is proposed. The search space of the proposed algorithm is optimized into the Tanner subgraphs of the codes to afford time-efficiency and search-effectiveness. For 5G New Radio (NR) base graph (BG) 2 LDPC codes for short blocklengths, the proposed algorithm finds more dominant fully absorbing sets within one seventh of the computation time of the existing search algorithm, and its search-effectiveness is verified using importance sampling. The proposed method is also applied to 5G NR BG1 LDPC code and Advanced Television Systems Committee 3.0 type A LDPC code for large blocklengths.

Keywords

Acknowledgement

This work was supported by Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korea government (MSIT) (2018-0-00218, Speciality Laboratory for Wireless Backhaul Communications based on Very High Frequency)

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