ITE Transactions on Media Technology and Applications
Online ISSN : 2186-7364
Volume 1 , Issue 1
Showing 1-12 articles out of 12 articles from the selected issue
Special Section on Review of Media Technology and Applications
Regular Section
  • Shinichi Suzuki, Naoto Kogo, Takayuki Nakagawa, Tetsuomi Ikeda
    2013 Volume 1 Issue 1 Pages 60-69
    Published: 2013
    Released: January 01, 2013
    JOURNALS FREE ACCESS
    We are developing a millimeter-wave mobile camera that wirelessly transmits 100 Mbps class High-definition TV (HDTV) video at low compression and with low latency. To realize an uninterrupted wireless transmission while maintaining a high transmission rate, we are investigating the application of multiple-input multiple-output (MIMO) multiplexed transmission technique and millimeter-wave band that enable the use of wide bandwidth. In this article, with the aim of enabling this camera to operate in outdoor line-of-sight (LOS) environments, we performed an evaluation of cross polarized MIMO multiplexed transmission with a horizontally/vertically polarized omni antenna using a film polarizer. As a result, we were able to suppress the transmit correlation between MIMO propagation channels to 0.45 or less, and we achieved a substantial improvement in bit error rate (BER) performance (median value reduced to about 1/30 or less). On the other hand, we have confirmed that the range within which uninterrupted wireless transmission is possible becomes smaller due to the reduction in received power in cross polarization, and we have clarified the cross polarization power ratio (XPR) suitable for LOS transmission environments.
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  • Suphakit Awiphan, Zhou Su, Jiro Katto
    2013 Volume 1 Issue 1 Pages 70-80
    Published: 2013
    Released: January 01, 2013
    JOURNALS FREE ACCESS
    Application-layer multicast has been considered as a promising method for streaming live media to users in P2P networks. However, the inefficient bandwidth utilization and the vulnerability to peer dynamics remain important issues. In this paper, we introduce a new approach to constructing an efficient overlay leveraging the strong features of tree and mesh methods. A core overlay is built in a fashion of multiple sub-trees, which allows each peer to receive data from other peers located in any different sub-trees. We propose a set of auxiliary connections, which connect between two nodes that do not have permanent parent/child relationship, to achieve a push-based data transmission from multiple parents without redundancy. Simulations through ns2 demonstrate that our scheme provides a good streaming quality with low end-to-end delay. Also, the proposed auxiliary links is beneficial in improving the resiliency of the overlay and utilizing the bandwidth of peers.
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  • Kohei Ohno, Makoto Itami, Tetsushi Ikegami
    2013 Volume 1 Issue 1 Pages 81-89
    Published: 2013
    Released: January 01, 2013
    JOURNALS FREE ACCESS
    Spectrum sharing techniques are attractive because the frequency bands for radio systems are limited. The cognitive radio technique and Ultra Wideband (UWB) system with a Detection and Avoidance (DAA) function are strong candidates for spectrum sharing. This paper discusses the techniques for detecting emissions from primary systems and the frequency bands they occupy. The received primary signals are assumed to be the sum of the sinusoidal waves. The sinusoidal signal is detected and is iteratively subtracted from the received signal to minimize the evaluation function. The frequency, phase and amplitude of the sinusoidal signals are estimated using the evaluation function and Newton method. The miss-Detection Error Rate and False Alarm Rate are evaluated to show the effectiveness of the proposed detection technique. The performance of the proposed detection scheme is superior to the ordinary scheme using FFT.
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