IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
Volume 11, Issue 2
Displaying 1-8 of 8 articles from this issue
  • Tsuyoshi Tanaka, Takashi Nishitsuji, Takuya Asaka
    Article type: LETTER
    Subject area: Network
    2022 Volume 11 Issue 2 Pages 70-74
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 12, 2021
    JOURNAL FREE ACCESS

    To solve network-related problems such as communication failures and network delays, a new network technology called an information-centric network (ICN) has been studied. However, there are various problems to be solved to develop ICNs, and they have not been put into practical use. In addition, research on ACOs for ICNs has not considered re-routing, which is the reuse of routing information left by other users. In this study, we propose a method of re-routing in an ICN with ant colony optimization by reusing routing information to achieve efficient routing.

    Download PDF (361K)
  • Akihito Noda
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2022 Volume 11 Issue 2 Pages 75-79
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 12, 2021
    JOURNAL FREE ACCESS

    Backscatter communication is a promising technology for low-power radio communications and will be useful also in two-dimensional communication (2DC) systems. A backscatterer (BX) modulates an externally supplied continuous wave (CW) by switching the terminating impedance of a 2DC surface coupler. The BX operates with very low power because it requires no radio frequency oscillator nor amplifier in itself. However, at the receiver (RX), separating the desired modulated signal and the interfering CW signal is a critical issue. In this paper, the BX generates a frequency-shifted modulation signal, and the RX rejects the strong CW by surface acoustic wave (SAW) filter. A prototype BX module achieved data transmission faster than 2Mb/s with 1.3mW power consumption. This technology provides insights into the practical use of 2DC for intelligent spaces and the Internet of Things (IoT).

    Download PDF (1223K)
  • Kyosuke Sugiura, Masaki Murakami, Yoshihiko Uematsu, Satoru Okamoto, N ...
    Article type: LETTER
    Subject area: Network System
    2022 Volume 11 Issue 2 Pages 80-85
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 12, 2021
    JOURNAL FREE ACCESS

    We have proposed the 10 Tbps class dynamic bandwidth flexible Ethernet-based massively parallel media access control (MAC) system; “Dynamic MAC”. The dynamic MAC requires up to 400 lanes parallel transmission and up to 10 ms skew canceling. Therefore, lane alignment among 400 lanes should be established. In this paper, numerical analysis results of lane alignment characteristics; alignment time and link-up time of the dynamic MAC system, are presented.

    Download PDF (180K)
  • Bin Sheng
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2022 Volume 11 Issue 2 Pages 86-92
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 22, 2021
    JOURNAL FREE ACCESS

    Simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is a new kind of metasurface which can transmit and reflect incident signals to users located at both sides of the surface. At each element of STAR-RIS, two coefficients are used to adjust the phase shifts and amplitudes of the transmitted and reflected signals. Thus, the overall power needs to be split between transmission and reflection coefficients for the sake of energy conservation. In this letter, we focus on the STAR-RIS aided downlink coordinated multipoint (CoMP) transmission and drive a close-form expression for the optimal power allocation when maximal ratio transmission (MRT) is used. Simulation results show that although this expression is only a approximate result, using it can also achieve the same bit error rate (BER) performance as that provided by the optimal power allocation.

    Download PDF (177K)
  • Osamu Kagaya, Takafumi Kikuchi, Keisuke Arai, Takuji Arima, Toru Uno
    Article type: LETTER
    Subject area: Antennas and Propagation
    2022 Volume 11 Issue 2 Pages 93-97
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 25, 2021
    JOURNAL FREE ACCESS

    In this paper, the effect of raindrops on an on-glass antenna is evaluated to appropriately design a C-band automotive antenna. A three-layer composite glass is used for the automotive window glass panel. The electromagnetic field analysis of a dipole on-glass antenna placed in the center of a 300 mm × 300 mm flat composite glass was performed. As a result, it was found that raindrop situation had no significant effect on the reflection characteristics of the antenna. However, the reflection coefficient of the antenna worsens when the raindrops were connected to each other and streaked in a direction parallel to the antenna.

    Download PDF (302K)
  • Ryo Yamada, Akihiro Kajiwara
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2022 Volume 11 Issue 2 Pages 98-103
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 25, 2021
    JOURNAL FREE ACCESS

    This paper is concerned with automotive networks and suggests the use of wireless signal to replace current wired signal between some ECU nodes for the improvement of fuel efficiency and reduction of fossil fuel usage. Considering the wireless connection channel, it would be blocked by passenger’s body and seat, for example, thereby resulting in channel deterioration. This paper presents a wireless approach based on automotive ceiling reflection where the ceiling simply performs as reflector. The ceiling will be able to offer stable wireless link for all the nodes. Measurement was conducted in 60 GHz band and the results are compared with conventional wireless approach. As a result, our suggested approach is found not to be affected by passengers and seat.

    Download PDF (979K)
  • Atsuya Nakamura, Yuta Kumagai, Shuhei Saito, Hirofumi Suganuma, Keita ...
    Article type: LETTER
    Subject area: Wireless Communication Technologies
    2022 Volume 11 Issue 2 Pages 104-110
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: November 26, 2021
    JOURNAL FREE ACCESS

    This study investigates the throughput performance of faster-than-Nyquist (FTN) signaling in the presence of nonlinear distortion under multipath fading channels. In our performance evaluation, we use a practical transmission method, in which single-carrier with frequency-domain equalization (SC-FDE) is applied to FTN signaling for broadband wireless communications. For a radio propagation model, the 3GPP tapped delay line (TDL) model is used to evaluate the effect of multipath fading, and the Rapp model is adopted as a power amplifier (PA) model that provides the impact of nonlinear distortion. We compare the throughput performance of FTN signaling with that of Nyquist signaling under the same transmission rate via computer simulations, which clarifies the applicability of FTN signaling to practical broadband wireless communications.

    Download PDF (272K)
  • Jumpei Usui, Ryo Shibata, Hiroyuki Yashima
    Article type: LETTER
    Subject area: Fundamental Theories for Communications
    2022 Volume 11 Issue 2 Pages 111-116
    Published: February 01, 2022
    Released on J-STAGE: February 01, 2022
    Advance online publication: December 01, 2021
    JOURNAL FREE ACCESS

    We propose a deep-learning-aided low-density parity-check (LDPC) coding scheme for two-user Gaussian multiple access channels with equal rate and equal average power constraints. The proposed neural network model simultaneously optimizes the power allocations and the joint decoder for a given power constraint and LDPC codes. Numerical results show that the proposed scheme achieves a better bit error rate performance than existing schemes for shorter code lengths and fewer decoding iterations.

    Download PDF (216K)
feedback
Top