Jun-ichi Takada

Publications (4)0.18 Total impact

• Conference Proceeding: MIMO channel capacity measurement in the presence of spatial clusters using a fading emulator.

  Tsutomu Sakata, Atsushi Yamamoto, Koichi Ogawa, Jun-ichi Takada
  Proceedings of the IEEE 20th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2009, 13-16 September 2009, Tokyo, Japan; 01/2009
• Source

  Available from: titech.ac.jp

  Article: Concept of diversity antenna gain

  Jun-Ichi Takadaand, Koichi Ogawa, Jun-Ichi Takada
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  ABSTRACT: To evaluate the performance of the diversity antennas, MEG of each antenna and correlation between them have been used as the parameters. However, use of two separated values are inconvenient for the comparison between two different sets of diversity antennas. The authors have proposed the concept of diversity antenna gain, which is a single parameter that directly expresses the performance of the diversity antennas. This TD reviews the concept and definition of diversity antenna gain.
  04/2003;
• Article: An analysis of the effective performance of a handset diversity antenna influenced by head, hand, and shoulder effects—A proposal for a diversity antenna gain based on a signal bit‐error rate and analytical results for the PDC system

  Koichi Ogawa, Jun-ichi Takada
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  ABSTRACT: An analysis of the effective performance of a handset diversity antenna, comprising a whip antenna and a planar inverted F antenna (PIFA), has been made by introducing a new figure-of-merit, the Diversity Antenna Gain (DAG). The analysis includes the electromagnetic interaction with a human operator. The DAG can take account of all of the effects associated with effective antenna gains, unequal median values, and correlations between diversity branches, and therefore can directly indicate the system gain in a multiple radio wave environment. By using the DAG, a direct performance comparison between diversity antennas with different effective gains and correlations can be easily made from the viewpoint of particular system criteria. This comparison is difficult to make from the respective performances only. The analysis has been made on π/4-shift QPSK signals with the assumption of a PDC system with a postdetection two-branch selection combining method or a maximum ratio combining method. The analytical results indicate DAG characteristics under various incident wave propagation environments with head-to-radio separation, whip length, and inclination of the radio from the vertical as variable parameters. The results demonstrate the structural and environmental requirements for designing a diversity antenna with a high effective performance in an actual talk situation. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(6): 10–23, 2001
  Electronics and Communications in Japan (Part II Electronics) 05/2001; 84(6):10 - 23. · 0.18 Impact Factor
• Source

  Available from: titech.ac.jp

  Article: MIMO Performance Evaluation in a Street Microcell Using a Spatial Fading Emulator in Comparison with a Radio Propagation Test

  Atsushi Yamamoto, Sakata Tsutomu, Toshiteru Hayashi, Koichi Ogawa, Jesper Ø Nielsen, Gert F Pedersen, Jun-Ichi Takada, Kei Sakaguchi
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  ABSTRACT: This paper presents effectiveness of a RF-controlled spatial fading emulator on MIMO performance evaluation in a street microcell environment in comparison with a radio propagation test. The fading emulator can produce a radio propagation environment with a uniform and non-uniform angular power spectra (APS) in the horizontal plane. In this paper, we measured MIMO characteristics of four handset arrays in a multipath environment with one cluster by the emulator. From this, good agreement between the results obtained by the emulator and experimental data of a radio propagation test in a street microcell reveals the emulator to be effective in evaluating the handset MIMO performance in a multipath environment. The study presented in this paper was conducted under the collaboration between Tokyo Institute of Technology, Japan and Panasonic Corporation, Japan. The propagation test presented here was performed under the collaboration among Aalborg University, Denmark and Panasonic Corporation and Panasonic Mobile Communications Corporation, Japan.