IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
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Showing 1-10 articles out of 10 articles from the selected issue
  • Sogo Furuya, Kenji Kurokawa
    Type: LETTER
    Subject area: Optical Fiber for Communications
    2020 Volume 9 Issue 9 Pages 400-404
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 16, 2020
    JOURNALS FREE ACCESS

    We have realized a fiber fuse terminator consisting of a commercially available short length of step-index multimode fiber, spliced with conventional SMFs. The fabricated fiber fuse terminator suppressed the fiber fuse propagation when the input power was 6 W, at a wavelength of 1.55 μm.

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  • Keiji Jimi, Akihiro Kajiwara, Yasushi Yamazaki
    Type: LETTER
    Subject area: Sensing
    2020 Volume 9 Issue 9 Pages 405-410
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 16, 2020
    JOURNALS FREE ACCESS

    In this paper, we present a bathroom monitoring sensor system using a 79GHz ultra-wideband radar sensor. It offers low privacy and anti-humidity capability unlike imaging sensors and IR sensors. It is designed to detect various dangerous states such as falling and drowning with Hidden Markov Model (HMM). We conducted experiments in order to show the effectiveness which is also compared with a conventional scheme. It has been found that our proposed scheme is more accurate than the conventional method.

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  • Jin Ren, Guohao Ma, Libin Ji
    Type: LETTER
    Subject area: Wireless Communication Technologies
    2020 Volume 9 Issue 9 Pages 411-415
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 24, 2020
    JOURNALS FREE ACCESS

    We propose a new method to combine the Knn algorithm with the neural network. Due to the size of the training set affects the accuracy of the training results, we propose a neural network with selective training set. Its main method is changed the size of the training set by a control variable to get the most suitable training data. The advantage of this method is that the training set can be adjusted to achieve a trade-off between the positioning accuracy and the training set size. The result of Knn algorithm positioning is more accurate by adding BP (Back Propagation) selective neural network algorithm.

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  • Naobumi Michishita, Luong Anh Tuan, Takahiro Hashimoto, Hisashi Morish ...
    Type: LETTER
    Subject area: Antennas and Propagation
    2020 Volume 9 Issue 9 Pages 416-420
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 24, 2020
    JOURNALS FREE ACCESS

    The use of ultra-high frequency radio frequency identification (RFID) technology has recently been studied for the wireless management of consumable parts in automobiles. The RFID tag antennas attached to the consumable parts in an engine room, which is a closed metal space, require horizontal polarization and omnidirectional radiation characteristics. This paper presents the design results of a circular folded dipole antenna for an RFID tag on a metallic cylinder.

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  • Lin Wang, Hiroki Hagiwara, Yuko Rikuta, Toshiyuki Kobayashi, Hiromi Ma ...
    Type: LETTER
    Subject area: Antennas and Propagation
    2020 Volume 9 Issue 9 Pages 421-425
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 30, 2020
    JOURNALS FREE ACCESS

    A reflectarray with upper sidelobe level (SLL) suppression is proposed for the fifth generation (5G) wireless communications in this letter. A unit cell of the reflectarray is composed of a crossed-dipole element to realize dual-polarized operation. In order to validate the improvement of upper SLL, a 45 degree-beam-steering reflectarray, comprising 20×10 elements, operating at 28GHz for quasi-millimeter-wave applications is designed and analyzed numerically. Simulation results demonstrate that the worst value of all upper SLL in radiation pattern of the reflectarray is reduced by about 10dB as compared to that in previous design.

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  • Ya Zhu, Akihito Noda, Masahiro Fujiwara, Yasutoshi Makino, Hiroyuki Sh ...
    Type: LETTER
    Subject area: Transmission Systems and Transmission Equipment for Communications
    2020 Volume 9 Issue 9 Pages 426-432
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 30, 2020
    JOURNALS FREE ACCESS

    Two-dimensional communication (2DC) textile is a technical combination of e-textile and two-dimensional signal transmission (2DST) technology. 2DC textile-based wearable system has several benefits, whereas designing a transmission scheme that ensures both power and high data rate transfer among numerous distributed devices on the textile is still challenging work. This paper proposes a charge/communication switching approach based on a baseband transmission system without modulation/demodulation of carriers. Successful power and more than 1 Mbps, half-duplex data transfer between one master and ten slaves was achieved. We also explain the trade-off relationship between the charging power, data rate, and device number by applying this approach.

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  • Fumiyuki Adachi, Ryo Takahashi
    Type: LETTER
    Subject area: Wireless Communication Technologies
    2020 Volume 9 Issue 9 Pages 433-439
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 30, 2020
    JOURNALS FREE ACCESS

    Multi-user MIMO and spatial diversity are attractive techniques to improve the link capacity. In this paper, multi-user zero-forcing (ZF) coordinated with user-wise maximal-ratio transmitting and combining (MRTC) diversity is studied. A closed-form expression for the received signal-to-noise ratios (SNRs) achievable with 2-user ZF coordinated with user-wise MRTC diversity is derived for the given MIMO channel condition. It is shown from the derived SNR expression that the uplink capacity is higher than the downlink capacity and that the uplink capacity is not necessarily the same among users while the downlink SNR is always identical for users. This is confirmed by numerical evaluation assuming a Rayleigh fading environment.

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  • Satomi Masuda, Erika Shigematsu, Kunihisa Jitsuno, Keizo Inagaki, Atsu ...
    Type: LETTER
    Subject area: Navigation, Guidance and Control Systems
    2020 Volume 9 Issue 9 Pages 440-445
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: June 30, 2020
    JOURNALS FREE ACCESS

    We investigated a two-frequency secondary radar system to prevent traffic accidents between pedestrians and vehicles at intersections with poor visibility. We measured a ranging property between a vehicle and a pedestrian, and direction detecting property. This paper shows the results of these experiments measured in a large anechoic chamber with a wooden L-shaped wall to emulate an NLOS condition. A measurement error in NLOS was larger than that in LOS. However, it was able to detect a pedestrian in NLOS and the direction of the one.

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  • Nobuo Kuwabara, Tohlu Matsushima, Yuki Fukumoto
    Type: LETTER
    Subject area: Electromagnetic Compatibility (EMC)
    2020 Volume 9 Issue 9 Pages 446-450
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: July 09, 2020
    JOURNALS FREE ACCESS

    The analysis method using the chain parameter matrix (F-matrix) has been proposed for calculating radiated emission from the cable used by power line communication (PLC). In this paper, the radiation resistance was implemented to the F-matrix as the load of the common mode current which was converted from the differential mode PLC signal by the unbalance of the transmission system and was considered as the emission source. The calculated result for the simple cable model was compared to the measurement value and to the calculation value of which the radiation resistance was not considered. The investigation result indicated that the influence of radiation resistance appeared at the frequency where the high radiated emission was observed.

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  • Taichi Yokouchi, Kohei Akimoto, Mizuki Motoyoshi, Suguru Kameda, Norih ...
    Type: LETTER
    Subject area: Wireless Communication Technologies
    2020 Volume 9 Issue 9 Pages 451-456
    Published: September 01, 2020
    Released: September 01, 2020
    [Advance publication] Released: July 09, 2020
    JOURNALS FREE ACCESS

    Millimeter-wave (mmW) wireless body area network (WBAN) is effective in reducing inter-WBAN interference because of the large attenuation by human body blocking. In this paper, for evaluating the interference power and the channel capacity of mmW WBAN in consideration of the regularity of the arrangement of users, we proposed a user arrangement model which is assumed an actual overcrowded train. In the proposed model, the channel capacity was calculated in consideration of the user’s shape, arrangement, and direction in the train. As a result of the computer simulation with the proposed model, it is concluded that the channel capacity of the overcrowded train environment with regularity in user arrangement varies more than that of a random environment.

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