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
  • Yasumasa Naka, Masaya Tamura
    Type: LETTER
    Subject area: Energy in Electronics Communications
    2020 Volume 9 Issue 10 Pages 457-463
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 10, 2020
    JOURNALS FREE ACCESS

    Capacitive wireless power transfer is performed using large electrodes or using a medium having high relative permittivity such as water. The transfer efficiency demonstrates a pronounced change with frequency. A lumped-constant equivalent circuit with parasitic elements represents the change. However, a relationship between conditions for generating minimum/maximum values of the transfer efficiency and structural parameters of the electrodes in the coupler has not clarified. In this study, an equivalent circuit is proposed using a distributed-constant circuit. We converted the lumped-constant circuit into two open-ended directional couplers. From the result, we derived the conditions for generating the minimum and maximum values of the voltage input/output ratio. The efficiencies calculated by the distributed-constant circuit and electromagnetic simulation were in good agreement.

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  • Yasushi Yuminaka, Keigo Taya, Yosuke Iijima
    Type: LETTER
    Subject area: Transmission Systems and Transmission Equipment for Communications
    2020 Volume 9 Issue 10 Pages 464-469
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 14, 2020
    JOURNALS FREE ACCESS

    Four-level pulse amplitude modulation (PAM-4) data formats are adopted to achieve next-generation high-speed data transmission standards. In this letter, a novel eye-opening monitoring technique based on machine learning is proposed to evaluate the received signal quality for the adaptive coefficients setting of a transmitter feed-forward equalizer for PAM-4 signaling. The monitoring technique employs a Gaussian mixture model (GMM) to classify the received PAM-4 symbols. Simulation and measured results of the coefficient adjustment using the GMM method are presented.

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  • Kazuyuki Ishida, Satoshi Yoshima, Ayano Sakamoto, Takashi Suehiro, Mas ...
    Type: LETTER
    Subject area: Sensing
    2020 Volume 9 Issue 10 Pages 470-475
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 27, 2020
    JOURNALS FREE ACCESS

    Optical remote sensing has been greatly expanded by the construction of satellite constellations and improving the performance of the optical sensors. As the data throughput of earth observation satellites increases, photonic technology is expected to be used for the interconnections within the payload in order to reduce its overall size, mass, and power consumption, and to improve its immunity to EMI. Here, we propose an optical time division multiplexing technology for N+1 redundancy in the payload, which is able to improve reliability by reducing the number of active components in the satellites, and present a feasibility study on its transmission efficiency.

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  • Takuma Watanabe, Hiroyoshi Yamada, Yasuyuki Oishi
    Type: LETTER
    Subject area: Sensing
    2020 Volume 9 Issue 10 Pages 476-481
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 27, 2020
    JOURNALS FREE ACCESS

    In this letter, we present the first demonstration of the spectral domain polarimetric decomposition concept with an airborne circular synthetic aperture radar (CSAR) dataset. In CSAR systems, radar-carrying aircraft moves along a circular path that encloses the desired target area. The CSAR image contains the scattering characteristics of the target with respect to the azimuth angle, and we can retrieve it by transforming the spatial domain image into its spectral domain representation. Furthermore, the application of polarimetric decomposition to the spectral domain CSAR image provides additional information about the polarimetric scattering mechanisms. We used a publicly released airborne polarimetric CSAR dataset for the demonstration.

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  • Takashi Ohira
    Type: LETTER
    Subject area: Transmission Systems and Transmission Equipment for Communications
    2020 Volume 9 Issue 10 Pages 482-488
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 31, 2020
    JOURNALS FREE ACCESS

    This paper considers how a class-E amplifier behaves when the load deviates from its nominal impedance. The Kirchhoff’s law and Fourier series formulate the circuit into three simultaneous equations. These equations are decomposed into zeroth- and first-order terms to apply the perturbation technique. The zeroth-order solutions meet the zero-voltage and zero-current switching conditions. The first-order formulas express the DC current consumption, RF output amplitude and phase, equivalent output impedance, and periodic turn-on power dissipation in terms of the load resistance and reactance deviations.

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  • Mampei Kasai, Hidekazu Murata, Toshiro Nakahira, Koichi Ishihara, Taka ...
    Type: LETTER
    Subject area: Wireless Communication Technologies
    2020 Volume 9 Issue 10 Pages 489-494
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 31, 2020
    JOURNALS FREE ACCESS

    Terminal-collaborated multiple-input multiple-output (MIMO) reception with adaptive terminal selection schemes has been studied experimentally. In the experimental system, frequency-domain iterative MIMO equalization was employed, and its performance was evaluated by making use of recorded signal waveforms in a measurement campaign. In iterative signal processing, it is known that early stopping can control unnecessary iterations. In this letter, it is revealed that early stopping can not only reduce computational complexity, but also improve the bit error ratio performance of iterative processing. This is because early stopping prevents the iteration process from causing errors.

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  • Kazuyuki Ishida, Satoshi Yoshima, Ayano Sakamoto, Takashi Suehiro, Mas ...
    Type: LETTER
    Subject area: Satellite Communications
    2020 Volume 9 Issue 10 Pages 495-500
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: July 31, 2020
    JOURNALS FREE ACCESS

    The digital payload for next generation high throughput communication satellites is expected to reduce the operators’ CAPEX and OPEX. Photonic technologies, which have a great affinity with digital signals, have been studied in order to increase the data throughput and reduce the mass of the satellites. Here, we propose an optical time division multiplexing system for routing the signals in the digital channelizer and have conducted a feasibility study on the transmission efficiency. This system has the potential to reduce the cost, mass, and power consumption, and to improve reliability by cleaning up the switches used for routing the signals within the satellites.

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  • Kyo Minoguchi, Toshiaki Shitaba, Tomoaki Yoshida, Jun Terada
    Type: LETTER
    Subject area: Transmission Systems and Transmission Equipment for Communications
    2020 Volume 9 Issue 10 Pages 501-505
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: August 04, 2020
    JOURNALS FREE ACCESS

    We develop the first OLT-pluggable extended-loss-budget transceiver necessary for 10G/1G compatible PON with N: 1 redundant OLT protection. This paper newly define the requirement of the OLT transceiver supporting protection by assuming an additional loss of redundant function. The average output power of 6.95/8.35dBm and minimum receiver sensitivity of -32.02/-34.53dBm for 10G/1G are attained, respectively. Experiments also confirm 40-km-SMF transmission with no dispersion penalties. It achieves the 36.02/35.53-dB loss budget as 10G/1G OLT transceiver, where ONU transceiver’s specification is based on 10GBASE-PR40/1000BASE-PX40, successfully meeting required loss budget for N:1 redundant OLT protection.

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  • Kazuya Inoue, Koichi Ichige, Tatsuya Nagao, Takahiro Hayashi
    Type: LETTER
    Subject area: Antennas and Propagation
    2020 Volume 9 Issue 10 Pages 506-511
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: August 13, 2020
    JOURNALS FREE ACCESS

    In this paper, we propose a radio propagation prediction method using machine learning and building occupancy estimation. There have been learning-based researches using aerial photographs and building occupancy images as spatial information. However, the availability of building occupancy images are often limited to urban areas. We assume the situation that only the aerial photographs are available, and aim to improve radio propagation prediction accuracy by estimating building occupancy images from the given aerial photographs.

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  • Akio Ikami, Takahiro Hayashi, Yoshiaki Amano
    Type: LETTER
    Subject area: Wireless Communication Technologies
    2020 Volume 9 Issue 10 Pages 512-518
    Published: October 01, 2020
    Released: October 01, 2020
    [Advance publication] Released: August 14, 2020
    JOURNALS FREE ACCESS

    For the efficient use of frequency resources, dynamic spectrum allocation (DSA) between different radio systems is promising. In DSA, our approach is to allow different mobile network operators to use the same shared channel without the inter base station (BS) interference. However, this approach is computationally very expensive. Therefore, we formulate this reuse channel allocation as a 0-1 mixed-integer linier programming problem and propose an algorithm to improve the satisfaction of each BS and the time and frequency continuities, which can be used to solve the problem in practical time. Our evaluation demonstrates that our proposed algorithm can improve the satisfaction with the time and frequency continuities simultaneously.

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