IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
Volume 3 , Issue 9
Showing 1-4 articles out of 4 articles from the selected issue
  • Tomoki Murakami, Yasushi Takatori, Masato Mizoguchi, Fumiaki Maehara
    Type: LETTER
    2014 Volume 3 Issue 9 Pages 263-268
    Published: 2014
    Released: September 05, 2014
    JOURNAL FREE ACCESS
    We propose a cross-layer switching method of orthogonal frequency division multiple access (OFDMA) and multiuser multiple input multiple output (MU-MIMO) for the future wireless local area network systems. The proposed method, employed on the medium access control layer, switches between OFDMA and MU-MIMO as the transmission method after processing by using physical layer information such as an overhead of channel state information feedback, station number, and data length in order to improve the transmission efficiency. Simulation results show that the proposed method achieves higher total throughput than conventional OFDMA or MU-MIMO where switching is not performed.
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  • Takaaki Ibuchi, Tsuyoshi Funaki
    Type: LETTER
    2014 Volume 3 Issue 9 Pages 269-274
    Published: 2014
    Released: September 08, 2014
    JOURNAL FREE ACCESS
    This study focuses on the effect of diode operating temperature on the conducted noise, induced by the reverse recovery current of the diode, of the continuous-current-mode boost DC–DC converter for the Si PiN diode (PiND) and SiC Schottky barrier diode (SBD). The result shows that the SiC SBD exhibits invariant switching behavior and predicts conducted emission level at the operating temperature. The peak reverse recovery current of the Si PiND increases at high operating temperatures. This study indicates that the temperature can affect the noise spectrum distribution for the variation of reverse recovery time and ringing oscillation.
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  • Nattapong Kitsuwan, Frank Slyne, Séamas McGettrick, David B. Payne, Ma ...
    Type: LETTER
    2014 Volume 3 Issue 9 Pages 275-280
    Published: 2014
    Released: September 10, 2014
    JOURNAL FREE ACCESS
    Network protection is a key feature of communications systems to ensure minimal packet loss when failure occurs in the data path. Segment protection is typically used to reroute data around a failed link, using secondary backup paths. We propose a novel solution to this problem, proposing an Independent Transient Plane (ITP) design that reduces the complexity of the path configuration process and the usage of resources in the routing elements, compared to current solutions. This work complements our previous studies, by reporting the results of an international testbed implementation over a pan-European network, showing protection times below 20 ms.
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  • Tuan Hung Nguyen, Takashi Oki, Hisashi Morishita, Hiroshi Sato, Yoshio ...
    Type: LETTER
    2014 Volume 3 Issue 9 Pages 281-286
    Published: 2014
    Released: September 30, 2014
    JOURNAL FREE ACCESS
    In this paper, we present a very simple multi-band technique for a wire inverted-F antenna designed for cellular application inside handset terminals, using multiple branch elements, single feeding port and only one shorting strip to simultaneously obtain good impedance matching at many different frequencies. The results in our investigation show that, the proposed technique is extremely straightforward, and can be simply applied to multi-band design of inverted-F antenna, so that it is possible to control easily and independently both the position and the number of all resonant frequencies.
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