Faculty Profiles - UEHARA Kazuhiro

MISC - UEHARA Kazuhiro

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無線信号処理クラウド化のカギ握る電波データ圧縮伝送技術

李斗煥, 山田貴之, 芝宏礼, 山口陽, 中川匡夫, 上原一浩

日経テクノロジーオンライン 2016.7

Radio spectrum transmission using compressed sensing for a Flexible Wireless System Invited

Doohwan Lee, Takayuki Yamada, Hiroyuki Shiba, Yo Yamaguchi, Tadao Nakagawa, Kazuhiro Uehara

Journal of IEICE 99 ( 5 ) 450 - 455 2016.5

A broad-band, low-noise, wide-dynamic-range SiGe frontend receiver IC for multi-band access points Reviewed

Takana Kaho, Yo Yamaguchi, Hiroyuki Shiba, Munenari Kawashima, Hideki Toshinaga, Kazuhiro Uehara

2013 Asia-Pacific Microwave Conference (APMC 2013) ( T2A-4 ) 267 - 269 2013.11

Authorship：Last author Language：English

A broadband, low-noise, wide dynamic range front-end receiver IC is reported. It uses 0.25 μm SiGe BiCMOS process technology and consists of broadband variable gain low noise amplifiers (VGLNAs), down-conversion mixers, step attenuators, and buffer amplifiers. It can receive triple-band signals concurrently, and the chip size is only 3mm × 3mm. Its measured noise figure was under 3.2 dB and the measured conversion gain was around 30 dB in the broad frequency range from 300 MHz to 3 GHz. It has a wide gain control range of around 100 dB
50 dB is controlled by the VGLNA and the step attenuator, and 50 dB by the mixer with novel relative power control method using dual LO signal. The gain control enhances the input 1dB compression point from -40 dBm to -21 dBm. © 2013 IEEE.

DOI： 10.1109/APMC.2013.6695115

Scopus

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Current status, issues, and future perspective of wireless home networks

Yasushi Takatori, Masato Mizoguchi, Kazuhiro Uehara, Shuichi Yoshino, Mitsuru Harada, Kazuyasu Okada

NTT Technical Review 11 ( 3 ) 1 - 5 2013.3

Current status, issues, and future perspective of wireless home networks

Yasushi Takatori, Masato Mizoguchi, Kazuhiro Uehara, Shuichi Yoshino, Mitsuru Harada, Kazuyasu Okada

NTT Gijyutsu Journal 25 ( 1 ) 12 - 15 2013.1

無線LANのすべて[第8回], 超高速を実現するミリ波無線LAN Invited

Ichihiko Toyoda, Ken Hiraga, Kazuhiro Uehara

Nikkei Communications 76 - 77 2011.5

Flexible Wireless System Invited

Yo Yamaguchi, Hiroyuki Shiba, Takana Kaho, Takayuki Yamada, Doohwan Lee, Kazuhiro Uehara

Radio Engineering and Electronics Association Newsletter, FORN ( 279 ) 2 - 5 2011.3

Ultra-high-speed transmission over millimeter-wave using microstrip antenna array Reviewed

Ken Hiraga, Tomohiro Seki, Kentaro Nishimori, Kenjiro Nishikawa, Kazuhiro Uehara

2010 IEEE Radio and Wireless Symposium (RWS 2010) Paper Digest 673 - 676 2010.1

Authorship：Last author Language：English

In microwave frequency bands, we have found that the application of spatial division multiplexing (SDM) using a number of antenna arrays is particularly effective for short transmission distances. We were also able to raise channel capacity in short-distance communication to several hundred Gbit/s by utilizing parallel transmission over a 60-GHz band with its wide bandwidth. When utilizing this technology, displacement of TX and RX antennas occurs because of the need to adjust the position of antennas manually by users. Antenna displacement causes deterioration in channel capacity. Electromagnetic field analysis results clarified the impact on channel capacity of antenna displacement that occurs in short-range transmission applications. Our results showed that channel capacity degradation is 10% when the horizontal antenna displacement is 1.5 mm and channel capacity degradation is only 2.7% when the rotational antenna displacement is 10°. The channel capacity degradation is smaller with longer transmission distances. © 2010 IEEE.

DOI： 10.1109/RWS.2010.5434243

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Towards ultrahigh-speed high-capacity networks

Masahiko Jinno, Hideaki Kimura, Yoshinori Hibino, Kazuhiro Uehara, Naoya Kukutsu, Fumihiko Ito, Shinji Matsuoka

NTT Technical Review 7 ( 5 ) 1 - 8 2009.5

Language：English

This article introduces technologies that will lead to future photonic networks that support ultrahigh capacities of 100 Gbit/s or more and services with low-latency end-to-end paths (huge-bandwidth services) as a common platform around 2020. Such networks will have on-demand, economical, and highly reliable access and core networks. Technology trends, requirements to be met, and challenges to be overcome are also described.

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Towards ultrahigh-speed high-capacity networks

Masahiko Jinno, Hideaki Kimura, Yoshinori Hibino, Kazuhiro Uehara, Naoya Kukutsu, Fumihiko Ito, Shinji Matsuoka

NTT Technical Journal 20 ( 11 ) 54 - 59 2008.11

Introduction to NTT patents: Multisector antenna (0) Invited

Kazuhiro Uehara, Tomohiro Seki, Kenichi Kagoshima

NTT Technical Review 5 ( 6 ) 1 - 3 2007.6

Introduction to NTT patents: Multisector antenna Invited

Kazuhiro Uehara, Tomohiro Seki, Kenichi Kagoshima

NTT Gijyutsu Journal 19 ( 6 ) 67 - 68 2007.6

Trends in Software Defined Radios Invited

Kazuhiro Uehara

Monthly JADI ( 713 ) 1 - 19 2006.10

Proposal and performance evaluation of wireless AO/DS system employing PHS (Translated from IEICE Transactions on Communications (Japanese Edition) Invited International journal

Hiroyuki Shiba, Kazuhiro Uehara, Shuji Kubota

Electronics and Communications in Japan (Part 1: Communications) 88 ( 5 ) 10 - 19 2005.5

Trends in research and development of software defined radio

Kazuhiro Uehara, Katsuhiko Araki, Masahiro Umehira

NTT Technical Review 1 ( 4 ) 10 - 14 2003.7

PHSから無線LANまで異なる無線方式に対応できるソフトウェア無線機を開発 Invited

Kazuhiro Uehara

NTT R&D 51 ( 3 ) 266 - 267 2002.3

PHSから無線LANまで異なる無線方式に対応できるソフトウェア無線機を試作 Invited

Kazuhiro Uehara

Journal of IEICE 85 ( 3 ) 222 2002.3

PHSから無線LANまで異なる無線方式に対応できるソフトウェア無線機を開発 Invited

Kazuhiro Uehara

NTT Gijyutsu Journal 14 ( 2 ) 74 - 75 2002.2

Trends in the research and development of software radio

Kazuhiro Uehara, Masashi Nakatsugawa, Shuji Kubota, Hideki Mizuno

NTT R&D 50 ( 1 ) 33 - 40 2001.1

Standardization activiteis for software defined radio

Masashi Nakatsugawa, Makoto Sugita, Kazuhiro Uehara

NTT R&D 50 ( 5 ) 57 - 62 2001.1

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