IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
Volume 4 , Issue 3
Showing 1-4 articles out of 4 articles from the selected issue
  • Daichi Higashi, Hiroyuki Deguchi, Mikio Tsuji
    Type: LETTER
    2015 Volume 4 Issue 3 Pages 85-88
    Published: 2015
    Released: March 13, 2015
    JOURNAL FREE ACCESS
    This letter presents novel resonant elements with four axial symmetry constructing a reflectarray for dual-polarization and wideband use. These elements have low cross-polarization property because the current flows on the strip elements cancel out cross polarized fields. To verify usefulness of the proposed elements, a reflectaray with offset feed is designed in Ku-band, and also the radiation pattern is investigated numerically and experimentally.
    Download PDF (1377K)
  • Shigenori Kinjo
    Type: LETTER
    2015 Volume 4 Issue 3 Pages 89-94
    Published: 2015
    Released: March 13, 2015
    JOURNAL FREE ACCESS
    Wireless communication systems using Tomlinson-Harashima precoding (THP) suffer from modulo operation error in noisy environments. The error causes fatal performance degradation when soft-input forward error correction is applied because the conventional soft demappers provide unreliable log-likelihood ratio (LLR) values. In this paper, we propose an efficient low complexity soft demapper with reliable LLR values for expanded M-QAM constellations of the THP systems. Computer simulations are given to show the effectiveness of the proposed demapper.
    Download PDF (610K)
  • Yoshihiro Kita, Kentaro Aburada, Mirang Park, Naonobu Okazaki
    Type: LETTER
    2015 Volume 4 Issue 3 Pages 95-98
    Published: 2015
    Released: March 26, 2015
    JOURNAL FREE ACCESS
    Most existing authentication methods have a common problem, referred to as shoulder-surfing, in which authentication information is covertly obtained by peeking over the shoulder of a user as he/she completes the authentication sequence. In this paper, we propose a puzzle authentication method that is very simple and sufficiently secure, even when the authentication sequence is being leaked. We also implemented the proposed method on a mobile terminal and is evaluated through experiments and questionnaire surveys.
    Download PDF (2801K)
  • Takashi Shinozuka, Katsumi Fujii, Akira Sugiura, Osami Wada
    Type: LETTER
    2015 Volume 4 Issue 3 Pages 99-104
    Published: 2015
    Released: March 30, 2015
    JOURNAL FREE ACCESS
    The measurements of the characteristics of an artificial mains network (AMN) are always affected by an AC-coaxial adapter connecting an impedance measuring equipment to the AMN. The present paper theoretically investigates the influences of the adapter on the measured AMN S-parameters in terms of the mode S-parameters. As a result, it proposes a correction method for eliminating the adapter influences in order to reveal the true AMN characteristics. The experimental measurements using two adapters of considerably different characteristics prove that the proposed method can yield almost the same estimates of the AMN impedance.
    Download PDF (769K)
feedback
Top