| 研究実績の概要 |
In the AY2022, we work on the proposal of a novel entanglement-based FSO/QKD system that uses LEO and GEO satellites. FSO/QKD systems using low-Earth orbit (LEO) satellites and EB scheme have been proposed previously. The LEO satellite benefits from the low channel loss; however, its coverage is limited. While a geosynchronous satellite (GEO) satellite with an altitude of 35,786 km can solve the coverage problem, the system suffers from a high path loss and limited key rates. Therefore, combining GEO and LEO satellites becomes a promising solution for the global-scale QKD network. In our proposal, we focus on designing a system that can support multiple wireless users, which opens the potential to establish a global-scale QKD network. Based on the design criteria for the proposed system, we investigate the feasibility of a case study for the Japan QKD network using the existing GEO satellite and LEO satellite constellation to provide QKD service for legitimate users in Japan. Furthermore, the secret key performance of the proposed system is studied based on the design criteria of transmitters and receivers considering the unauthorize receiver attack (URA) and beam-splitting attack (BSA). In particular, we aim to design the transmitted signal to prevent URA and propose a simple scheme that allows legitimate users to detect BSA. Besides, we work on issues related to the design and applications of satellite based FSO systems, including hybrid FSO/RF systems, error control and improvement using advanced hybrid ARQ technique.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The project progressed slightly delayed than the initial plan due to the COVID pandemic during the first year (AY2021). We successfully recruit 2 research assistants (MS/PhD student) from oversea. However, due to the border blockage situation in Japan, only one student managed to arrive and start working in AY2021. Starting from 2022, we have full manpower as planned. Therefore, WP1 and WP2 are progressed smoothly while WP3 is slightly delayed to the final year (AY2023).
We have a good progress in WP4 thanks to the fact that the Research Collaborator #2 remains in the research team after PhD graduation.
In overall, the project is progressed rather smoothly, and we have better achievement than target in terms of research result dissemination (WP5). In particular, in AY2022, our research results were published five journal articles and four conference papers.
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| 今後の研究の推進方策 |
In AY2023, we continue the WP2 which focuses on the system model and design for FSO-QKD and WP4 - investigation on various improvement techniques that lead to the achievement of the proposed system. Our main focus will be on WP3 - QKD protocol designs, analytical and simulation framework of protocols, We especially focus on the design concept of large-scale satellite-based QKD networks.
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