- 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
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
- Manabu Hagiwara
- 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.5, no.2, pp.49-51, 2016 (Released:2016-02-03)
- 参考文献数
- 3
- 被引用文献数
- 7
A short proof for the s-deletion error-correction property of Helberg codes is given.
- 著者
- Kotaro Matsuoka Yasutomo Yushima Ryo Hayakawa Riho Kawasaki Kazunori Hayashi Megumi Kaneko
- 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
- pp.2016XBL0012, (Released:2016-02-22)
This paper proposes a tag identification protocol built upon Boolean compressed sensing (CS) for radio frequency identification (RFID) systems. Unlike the conventional CS-based tag identification (CS-ID) protocol, the proposed protocol can cope with flat fading channels without explicit channel estimation. Simulation results show that the proposed scheme requires less amount of bits for successful identification than dynamic framed slotted ALOHA (DFSA) protocol, and that it even outperforms the conventional CS-ID protocol with perfect channel information.
- 著者
- Ken T. Murata Hidenobu Watanabe Kazunori Yamamoto Eizen Kimura Masahiro Tanaka Osamu Tatebe Kentaro Ukawa Kazuya Muranaga Yutaka Suzuki Hirotsugu Kojima
- 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.3, no.2, pp.74-79, 2014-02-25 (Released:2014-02-25)
- 参考文献数
- 6
- 被引用文献数
- 4 7
A variety of satellite missions are carried out every year. Most of the satellites yield big data, and high-performance data processing technologies are expected. We have been developing a cloud system (the NICT Science Cloud) for big data analyses of Earth and Space observations via spacecraft. In the present study, we propose a new technique to process big data considering the fact that high-speed I/O (data file read and write) is important compared with data processing speed. We adopt a task scheduler, the Pwrake, for easy development and management of parallel data processing. Using a set of long-time scientific satellite observation data (GEOTAIL satellite), we examine the performance of the system on the NICT Science Cloud. We successfully archived high-speed data processing more than 100 times faster than those on traditional data processing environments.
- 著者
- Ryutaroh Matsumoto
- 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.2, no.8, pp.343-346, 2013-08-15 (Released:2013-08-15)
- 参考文献数
- 5
- 被引用文献数
- 4
We propose a Gilbert-Varshamov-type existential bound for the relative dimension length profile and the relative generalized Hamming weight of nested pairs of linear codes.
- 著者
- Masanori Shinriki Hiroshi Takase
- 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.1, no.5, pp.165-170, 2012-10-16 (Released:2012-10-16)
- 参考文献数
- 4
Binary codes for a multi-range-resolution radar are proposed. Inverse filters can be then used for a multi-range resolution radar and compress the proposed codes to different pulse widths. These binary codes are compressed to several sub-pulses, only if a matched filter is applied. We describe that the compressed pulses have very small pulse compression losses and side-lobe amplitudes, even though the binary codes are compressed to the pulse width smaller than the reciprocal of the bandwidth of the codes. This fact is confirmed by computer calculations.
1 0 0 0 OA OSNR improvement by introducing intra-node arrayed optical amplifiers into multi-degree ROADM
- 著者
- Yohei Sakamaki Takeshi Kawai Tomoyoshi Kataoka Mitsunori Fukutoku
- 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.2, no.4, pp.148-153, 2013-04-15 (Released:2013-04-15)
- 参考文献数
- 8
We propose an intra-node arrayed optical amplifier (AOA) to improve the OSNR of received signals by reducing the insertion loss of multi-degree ROADM nodes. Our AOA shares a pump laser between several EDFAs with the aim of reducing the module size and manufacturing cost compared with the size and cost when only arraying discrete EDFA modules. We confirmed the feasibility of our fabricated AOA experimentally. The experimental results show that the pump power was properly distributed to each EDFA and the OSNR of the received signals was successfully improved for 128-Gbit/s PDM-QPSK signal transmission systems.