2022 Fiscal Year Research-status Report
| Project/Area Number |
20K04493
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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) |
2020-04-01 – 2024-03-31
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| Keywords | wireless communications / sensor networks / massive random-access / fading channel / slotted ALOHA |
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| Outline of Annual Research Achievements |
We are progressing according to the original plan in 2022, and achieved the following results.
Irregular Repetition Slotted ALOHA (IR-SA) scheme is an example of unsourced random access communications. It is simple and practical for applications. Over fading channels, however, the limit performances, i.e., theoretical bounds, of the IR-SA are unknown. In 2022, one of our works is to derive two theoretical bounds of IR-SA over fading channels: a maximum a posteriori (MAP) threshold and a converse bound. The MAP threshold is a theoretical upper bound of a practical decoding performance. The converse bound expresses an impossibility threshold to be approached. The bounds are guidelines for practical implementation of IR-SA.
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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 summarized in the Research Achievements section, the research is smoothly progressing according to the original plan in 2022.
For IR-SA scheme over Rayleigh fading channels, we proposed an asymptotic analysis of the decoding performance for systems. First, since an open decoding tunnel exists in an extrinsic information transfer (EXIT) chart, the sum of the two areas below two EXIT curves is smaller than the area of the entire domain. This gives a converse bound of the traffic, which is tight. Second, a coincidence of the belief propagation (BP) EXIT and maximum a posteriori (MAP) EXIT curves makes it possible to derive an MAP threshold of the traffic. Third, a density evolution for a spatially-coupled scheme is formulated and gives a BP decoding threshold of the traffic.
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| Strategy for Future Research Activity |
Part of this research results in 2022 have been summarized and will be presented in international conferences in 2023 (the extension year).
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| Causes of Carryover |
2022年度の一部の研究成果は，すでに論文にまとめ，2023年3月に学会誌に投稿しました．また，補助事業の目的をより精緻に達成するために，2023年10月の国際会議IEEE 9th World Forum on Internet of Thingsに参加する必要があり，延長を行うこととしました．
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