Hiroyuki Atarashi

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This paper proposes broadband packet wireless access employing Variable Spreading Factor-Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM) with two-dimensional spreading that prioritizes time domain spreading in the forward link and Multi-carrier/DS-CDMA (MC/DSCDMA) in the reverse link for the system beyond IMT-2000. Based on the wireless(More)
This paper proposes broadband packet wireless access employing variable spreading factor-orthogonal frequency and code division multiplexing (VSF-OFCDM) in the forward link and multicarrier(MC)/DS-CDMA in the reverse link for the system beyond IMT-2000. Based on wireless access schemes, we propose major radio air interface parameters in the physical layer(More)
Future-generation cellular wireless systems, transporting high bit rates in non-ideal radio propagation environments, must be robust to severe frequency selective multipath. Further requirements include moderate terminal and base station hardware costs, high spectral efficiency, and scalability of the cost of terminals with respect to their maximum bit rate(More)
OBJECTIVES In medical institutions, unauthorized access points and terminals obstruct the stable operation of a large-scale wireless local area network (LAN) system. By establishing a real-time monitoring method to detect such unauthorized wireless devices, we can improve the efficiency of security management. METHODS We detected unauthorized wireless(More)