2017 Fiscal Year Research-status Report
空間結合符号のユニバーサル性を活かした多重接続通信の理論限界達成に関する研究
| Project/Area Number |
16K06373
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| Research Institution | Doshisha University |
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Principal Investigator |
程 俊 同志社大学, 理工学部, 教授 (00388042)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | spatially coupled code / irregular code / LDPC code / channel capacity |
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| Outline of Annual Research Achievements |
We are progressing according to the plan in 2017, and achieved the following results.
We have proposed spatially-coupled irregular LDPC (low density parity check) codes by irregular superposition matrices. Starting with a binary base matrix and replacing non-zero entries in the base matrix by superposition matrices produces a parity-check matrix and its corresponding code ensemble. The proposed codes have two features: a) flexible code rates because the size of the superposition matrix is arbitrarily adjusted, and b) guaranteed iterative decoding performance because the weight distributions of the superposition matrix are optimized, even in a finite coupling width. The numerical analysis of density evolution and Monte-Carlo simulations show that our proposed code ensembles approach the Shannon limits at arbitrary code rates and outperform the conventional codes. Moreover, we analytically estimate the bit error rate (BER) and frame error rate (FER) of the proposed codes in error floor region. The numerical results show that the FER performances in the error floor regions of the proposed codes are superior to the conventional irregular LDPC code ensembles at almost identical belief-propagation thresholds.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
As summarize in the Research Achievements section, the research word is smoothly progressing according to the plan in 2017. The proposed spatially-coupled irregular LDPC codes have the feature of flexible code rates, and thus are available for multiple-access channel.
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| Strategy for Future Research Activity |
Although the proposed three (two in 2016, and one in 2017) kinds of the spatially coupled codes have the decoding performance approaching the channel capacity in finite code length, we still attempt to find a kind of spatially coupled codes with short code length for the practical purpose. So, in 2018, we will slightly change our original research plan. We will continue to propose more powerful spatially coupled codes with short code length. One way of our attempting is to couple Polar codes, since Polar code works relatively well in short code length. After that we will apply our proposed codes to some wireless communication scenarios followed our original plan.
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| Causes of Carryover |
（理由）
2017年度に予定していた成果発表を2018年11月の国際学会で行うことになったため．
（使用計画）
上記理由から，次年度使用額を2018年11月頃に国際会議参加費に支出します．
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Research Products
(23 results)
