The search functionality is under construction.

Author Search Result

[Author] Katsuhiro TEMMA(3hit)

1-3hit
  • Field-Trial Experiments of an IoT-Based Fiber Networks Control and Management-Plane Early Disaster Recovery via Narrow-Band and Lossy Links System (FRENLL)

    Sugang XU  Goshi SATO  Masaki SHIRAIWA  Katsuhiro TEMMA  Yasunori OWADA  Noboru YOSHIKANE  Takehiro TSURITANI  Toshiaki KURI  Yoshinari AWAJI  Naruto YONEMOTO  Naoya WADA  

     
    PAPER

      Pubricized:
    2020/05/14
      Vol:
    E103-B No:11
      Page(s):
    1214-1225

    Large-scale disasters can lead to a severe damage or destruction of optical transport networks including the data-plane (D-plane) and control and management-plane (C/M-plane). In addition to D-plane recovery, quick recovery of the C/M-plane network in modern software-defined networking (SDN)-based fiber optical networks is essential not only for emergency control of surviving optical network resources, but also for quick collection of information related to network damage/survivability to enable the optimal recovery plan to be decided as early as possible. With the advent of the Internet of Things (IoT) technologies, low energy consumption, and low-cost IoT devices have been more common. Corresponding long-distance networking technologies such as low-power wide-area (LPWA) and LPWA-based mesh (LPWA-mesh) networks promise wide coverage sensing and environment data collection capabilities. We are motivated to take an infrastructure-less IoT approach to provide long-distance, low-power and inexpensive wireless connectivity and create an emergency C/M-plane network for early disaster recovery. In this paper, we investigate the feasibility of fiber networks C/M-plane recovery using an IoT-based extremely narrow-band, and lossy links system (FRENLL). For the first time, we demonstrate a field-trial experiment of a long-latency/loss tolerable SDN C/M-plane that can take advantage of widely available IoT resources and easy-to-create wireless mesh networks to enable the timely recovery of the C/M-plane after disaster.

  • Interference-Aware Channel Segregation Based Dynamic Channel Assignment for Wireless Networks

    Yuki MATSUMURA  Katsuhiro TEMMA  Ren SUGAI  Tatsunori OBARA  Tetsuya YAMAMOTO  Fumiyuki ADACHI  

     
    PAPER-Network Management/Operation

      Vol:
    E98-B No:5
      Page(s):
    854-860

    Recently, we proposed an interference-aware channel segregation based dynamic channel assignment (IACS-DCA). In IACS-DCA, each base station (BS) measures the instantaneous co-channel interference (CCI) power on each available channel, computes the moving average CCI power using past CCI measurement results, and selects the channel having the lowest moving average CCI power. In this way, the CCI-minimized channel reuse pattern can be formed. In this paper, we introduce the autocorrelation function of channel reuse pattern, the fairness of channel reuse, and the minimum co-channel BS distance to quantitatively examine the channel reuse pattern formed by the IACS-DCA. It is shown that the IACS-DCA can form a CCI-minimized channel reuse pattern in a distributed manner and that it improves the signal-to-interference ratio (SIR) compared to the other channel assignment schemes.

  • 2-Step QRM-MLBD for Broadband Single-Carrier Transmission

    Katsuhiro TEMMA  Tetsuya YAMAMOTO  Kyesan LEE  Fumiyuki ADACHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E95-B No:4
      Page(s):
    1366-1374

    Maximum likelihood block signal detection employing QR decomposition and M-algorithm (QRM-MLBD) can significantly improve the bit error rate (BER) performance of single-carrier (SC) transmission while significantly reducing the computational complexity compared to maximum likelihood detection (MLD). However, its computational complexity is still high. In this paper, we propose the computationally efficient 2-step QRM-MLBD. Compared to conventional QRM-MLBD, the number of symbol candidates can be reduced by using preliminary decision made by minimum mean square error based frequency-domain equalization (MMSE-FDE). The BER performance achievable by 2-step QRM-MLBD is evaluated by computer simulation. It is shown that it can significantly reduce the computational complexity while achieving almost the same BER performance as the conventional QRM-MLBD.