著者

Nobuyasu Shiga Kohta Kido Satoshi Yasuda Bhola Panta Yuko Hanado Seiji Kawamura Hiroshi Hanado Kenichi Takizawa Masugi Inoue

出版者

(社)電子情報通信学会

雑誌

IEICE Communications Express (ISSN:21870136)

巻号頁・発行日

vol.6, no.2, pp.77-82, 2017 (Released:2017-02-01)

参考文献数

2

被引用文献数

12

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Wireless two-way interferometry (Wi-Wi) is the simplified version of “carrier phase based two-way satellite time and frequency transfer,” wherein a wireless communication technology is used instead of a satellite communication technology. We used the carrier phase of a 2.4 GHz ZigBee module to measure the variation of two rubidium clocks at remote sites. Since clocks in the ZigBee module are much less precise than rubidium clocks, the carrier phase of the ZigBee signal cannot be used to compare two rubidium clocks in a simple manner. Using a technique to cancel the clock error of transmitters, we demonstrated picosecond-level precision measurement of the time variation of clocks between two remote systems. This synchronization technique at picosecond-level precision opens the door to low-cost wireless positioning at millimeter accuracy.

著者

Daijiro Koyama Yunzhuo Wang Nobuyasu Shiga Satoshi Yasuda Nicolas Chauvet Makoto Naruse

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

Nonlinear Theory and Its Applications, IEICE (ISSN:21854106)

巻号頁・発行日

vol.12, no.2, pp.225-235, 2021 (Released:2021-04-01)

参考文献数

9

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The growing demand of high-bandwidth and low-latency information transfer in information and communication technologies such as data centers and in-vehicle networks has increased the importance of optical communication networks in recent years. However, complicated arbitration schemes can impose significant overheads in data transfer, which may inhibit the full exploitation of the potential of optical interconnects. Herein, we propose an arbitration protocol based on precision time synchronization via wireless two-way interferometry (Wi-Wi), and numerically validate its efficiency including the ability to impose a strict upper bound on the latency of data transfer. We introduce the notion of arbitration point (AP) for a designated time duration, which is shared by all nodes thanks to the time synchronization by Wi-Wi, to determine data transmission while ensuring avoiding collision. Compared with the conventional carrier sense multiple access/collision detection (CSMA/CD)-based approach, a significant improvement in the data transfer was observed especially in the cases with high traffic flow rate. Furthermore, we conducted a proof-of-principle experiment for Wi-Wi-based data transfer between two electrically connected nodes and confirmed that the skew was less than 300 ns and remained stable over time. Conversely, non-Wi-Wi-based data transfer exhibited huge and unstable skew. These results indicate that precision time synchronization is a promising resource to reduce the communication overheads and ensure low latency for future networks and real-time applications.