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IEEE SENSORS LETTERS 2023年第2期7卷

作者： Ogawa, Yuta Honma, Naoki Murata, Kentaro Iwai, Morio Kobayashi, Koichiro Iwate Univ Grad Sch Arts Sci Morioka 0208551 Japan

This letter proposes a modified constant modulus algorithm (CMA)-based beamforming method for a multiple-input-multiple-output (MIMO) radar to track and detect vital signs via blind processing. Our method consists of two key functions: 1) the beamforming weight and dc offset are jointly updated to remove the semiconstant clutter and maintain the constant amplitude, which is the original function of CMA, and 2) the weight is updated by considering the phase variance owing to the typical respiratory response to make the weight converge to the vital signs. The proposed method was experimentally evaluated by comparing its heart rate estimation accuracy with that of the conventional CMA-based and maximal-ratio combining (MRC)-based beamforming methods. The experimental results showed that the proposed beamforming method with and without the phase variance constraint achieved the median errors of 3.45 and 4.06 bpm from the reference electrocardiogram, respectively, whereas the conventional CMA-based and MRC-based beamforming methods achieved the median errors of 21.1 and 9.79 bpm, thereby demonstrating the effectiveness of the proposed method.

关键词： Microwave/millimeter wave sensors adaptive array antenna arctangent demodulation heart rate vital signs

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2D Angle of Arrival Estimations and Bandwidth Recognition for Broadband Signals 11

2D Angle of Arrival Estimations and Bandwidth Recognition fo...

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11th European Conference on antennas and Propagation (EUCAP)

作者： BniLam, Noori Steckel, Jan Weyn, Maarten Univ Antwerp MOSAIC Res Grp iMinds Antwerp Belgium Univ Antwerp Cosys Lab Res Grp Antwerp Belgium

ISBN: (纸本)9788890701870

In many angle of arrival (AoA) estimation algorithms for broadband signals a-prior knowledge about the impinging signals' bandwidth is required for the algorithms to function. In this paper, we present a new technique for estimating the AoA and the bandwidth of the received broadband signals without requiring any knowledge of the bandwidth of the received signals. The proposed technique consists of a uniform circular array (UCA) followed by a transversal filter. It employs variable bandwidth spatial vectors along with the signal to thermal noise ratio (STNR) estimator to estimate the AoA and the bandwidth of the received signals simultaneously. The simulation results illustrate the capabilities of the proposed technique in estimating not only the elevation and the azimuth of the impinging signals with different bandwidths, but also the bandwidths of these received signals.

关键词： broadband AoA estimation adaptive array antenna Transversal Filter MVDR algorithm UCA

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Unnecessary power radiation suppression technique using a transmit antenna directivity control in ubiquitous communication environments

Unnecessary power radiation suppression technique using a tr...

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18th IEEE International Symposium on Personal, Indoor and Mobile Radio Communication

作者： Yamanaka, Masaaki Morinaga, Norihiko Sampei, Seiichi Miyamoto, Shinichi Hiroshima Int Univ Dept Informat & Commun Technol 1-1-5 Shinkoshingai Hiroshima Japan Osaka Univ Grad Sch Engn Suita Osaka Japan

ISBN: (纸本)9781424411436

This paper will propose an unnecessary radiation power suppressing technique to electromagnetically restricted areas in ubiquitous communication environments. An adaptive array antenna is employed in each terminal to control a directivity of transmit antenna not to radiate unnecessary power to the electromagnetically restricted areas while keeping sufficient gain to a target terminal. To identify angle of departures to the electromagnetically restricted areas, a radio power sensor network is assumed. Moreover, channel sounding based delay profile estimation is conducted to identify the strongest path direction for the desired signal. Based on the identified strongest path for the desired signal and the direction of the unwanted radiation detected using the radio power sensor network, artificial delay profile for a transmitted signal is created, and antenna directivity for the transmitted signal is created using a deep and wide null creation technique based on the artificial delay profile. Computer simulation confirms that the unnecessary radiation to the electromagnetically restricted areas is sufficiently suppressed while keeping throughput at a satisfactory level.

关键词： radiational power suppressing adaptive array antenna

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79GHz-band Millimeter-Wave Radar High Precision and Wide Field of View Technologies

79GHz-band Millimeter-Wave Radar High Precision and Wide Fie...

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Asia-Pacific Microwave Conference Proceedings

作者： Miyamoto, Kazuhiko Nakagawa, Yoichi Panasonic Corp Device Solut Ctr R&D Div Kadoma Osaka Japan

ISBN: (纸本)9784902339314

"79GHz high resolution radar" is expected to be used for future safety related applications which reduce traffic fatalities because of its capability for detecting pedestrians and bikes. At intersections where are the cause of about a half of fatalities in Japan, infrastructure cooperative systems have been studied that intend for driver's safety support. So that we have tried to advance millimeter-wave radar technologies toward to apply such intersection surveillance, it is able to perform as not only high precision by using coded pulse modulation but also wide field-of-view by using adaptive array antenna.

关键词： Millimeter-wave radar 79GHz-band infrastructure cooperative system adaptive array antenna coded pulse modulation

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Coexistence of OFDM-Based WLANs by VIrtual subcarrier assignment (VISA) with multiple subcarrier puncturing

Coexistence of OFDM-Based WLANs by VIrtual subcarrier assign...

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60th IEEE Vehicular Technology Conference

作者： Jia, YY Hara, S Osaka Univ Grad Sch Engn Dept Elect Informat Syst & Energy Engn Suita Osaka 5650871 Japan

ISBN: (纸本)0780385217

We have proposed a novel spatial filtering technique named "VIrtual Subcarrier Assignment (VISA)" for OFDM signals, which colors OFDM signals with different virtual subcarrier positions in their spectra to enable adaptive array antenna at the receiver to accept the OFDM signals selectively. In this paper, we propose an attractive application of the VISA with multiple virtual subcarriers to easily realize the coexistence of multiple WLANs in a localized area. In addition, we present a multi-step RLS-based weight control algorithm to support the VISA with multiple subcarrier puncturing in an IEEE802.11a-based system. The validity of the proposed system is verified by simulation results.

关键词： OFDM adaptive array antenna virtual subcarrier assignment multiple subcarrier puncturing WLAN

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Enhancement of data throughput in the AMC-employed DS-CDMA systems through suppression of channel frequency selectivity by a MTMR antenna system

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IEICE TRANSACTIONS ON COMMUNICATIONS 2005年第4期E88B卷 1622-1631页

作者： Kim, J Sampei, S Morinaga, N Osaka Univ Grad Sch Engn Dept Commun Engn Suita Osaka 5650871 Japan Hiroshima Int Univ Fac Infrastruct Technol Hiroshima 7370112 Japan

In this paper, a new algorithm for MTMR adaptive array antenna (AAA) system combined with analog-type transmit power control (TPC) is proposed for DS-CDMA systems in order to employ high level modulation schemes like 64 QAM in wireless multimedia services. A conventional AAA system considering the strongest path as a target path cannot work effectively when angular dispersion between the strongest path and other delayed paths is large, that is, beam selectivity is so small due to severe frequency selective multipath fading. So, in order to solve such a beam selectivity problem, a beam directivity control scheme using a path manipulation technique is introduced for the BS and MS AAA combining in this paper, along with analog-type TPC. It utilizes virtual delay profiles which are modified from the measured complex delay profile and selects a desired path giving the maximum DUR with an optimized weight vector for BS and MS beamforming. We will show through computer simulation that the proposed scheme is very effective in enhancing the data throughput at the downlink of wideband DS-CDMA systems as compared with the conventional system.

关键词： MTMR DS-CDMA adaptive array antenna analog-type TPC frequency selectivity test

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Invariant subspace reduced-dimension AMF-CFAR test

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 1999年第5期53卷 247-253页

作者： Luoyi Liu, GS Gu, H Su, WM Nanjing Univ Sci & Technol Inst Photo & Elect Nanjing 210094 Peoples R China

In the paper, a new method for reducing the dimension is introduced for reduced-dimension STAP. With the new method, it is found that the reduced-dimension AMF-CFAR test may provide the same optimal performance as the full-dimension AMF-CFAR test, if the covariance matrix Is known, and provide nearly optimal performance if the covariance matrix is unknown, even when the reduced degree of freedom of the system is very small.

关键词： STAP array signal processing adaptive array antenna multi-dimension signal processing

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Structures and theories of software antennas for software defined radio

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IEICE TRANSACTIONS ON COMMUNICATIONS 2000年第6期E83B卷 1189-1199页

作者： Kohno, R Yokohama Natl Univ Fac Engn Yokohama Kanagawa 2408501 Japan

Software radio or software defined radio (SDR) is a quite attractive field of research in terms of theoretical crossover research themes between radio engineering and computer science in academia as well as new multi-standard or all-purpose radio system products in industry [1], [2]. In order to promote research and development in a field of SDR this paper briefly introduces some prospective aspect. and research themes on SDR. There are many approaches to research SDR such as architectures, devises, algorithms, description languages and API (application program interface) for achieving reconfigurability and downloadability in an SDR system. One of the approaches is to focus on an antenna for SDR. Although a baseband circuit is generally programable and reconfigurable, an antenna and a RF circuit are used to be less flexible and hardware-dependent and then result in a bottleneck for implementing an SDR system. However, an adaptive array antenna or a smart antenna named a software antenna is adaptively controllable and reconfigurable because it can be programable to form a desired beam partern if an appropriate set of antenna weights is provided with software. It must be a vital tool for carrying out an SDR system. A soft ware antenna can be considered as an adaptive filter in space and time domains for radio communications, so that the communication theory can be generalized from a conventional time domain into both space and time domains. This paper also introduces structures and theories of a software antenna which I have been studying before this millennium.

关键词： software defined radio (SDR) adaptive array antenna software antenna space-time coding

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Frequency sharing hotspot communication under uplink multi-carrier CDMA cellular system

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2008年第5期8卷 563-573页

作者： Khoa, Nguyen Tran Fujii, Takeo Umebayashi, Kenta Kamiya, Yukihiro Suzuki, Yasuo Tokyo Univ Agr & Technol Dept Elect & Elect Engn Koganei Tokyo 1848588 Japan Univ Electrocommun Adv Wireless Commun Res Ctr Chofu Tokyo 1828585 Japan

In multi-carrier CDMA cellular systems, hotspot communication can be established to support the high-traffic areas by using the same frequency band of the original cellular systems. However, interference from the hotspots deteriorates the communication performance of the original cellular system. In this paper, in order to decrease the interference, we set up the access point (AP) of hotspots with the adaptive array antenna and code assignment method between the cellular and the hotspot communication is considered. In the proposed system, OFDM hotspot communication is overlapped to the uplink of MC/DS-CDMA cellular system in the same frequency band and the beam-forming method is applied to eliminate inter-system interference. Moreover, by allocating orthogonal variable spreading factors (OVSF) code to the both hotspot users and cellular users in the hotspot uplink period, the orthogonality of each user is kept. As a result, we can embed many hotspots into the cellular system with very small interference toward the uplink communication of the cellular system and we can improve the throughput of total system. The performance of the proposed system is evaluated by computer simulation under additive white Gaussian noise (AWGN) and Rayleigh fading environment. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： multi-carrier CDMA hotspots adaptive array antenna

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A simple design method of the planar butler matrix using thin dielectric substrate metalized both side

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IEICE TRANSACTIONS ON ELECTRONICS 2003年第2期E86C卷 162-168页

作者： Isota, Y Ishida, S Takeda, F Mitsubishi Electr Corp Informat Technol R&D Ctr Kamakura Kanagawa 2478501 Japan Okayama Univ Sci Dept Elect Engn Okayama 7000005 Japan

adaptive antenna is a promising to increase the spectral efficiency of mobile radio systems. We developed a compact, cost effective planar Butler Matrix as a beam forming network of a multi beam antenna. This circuit consists of a thin substrate that the conductor attaches to both sides, and two thick substrates that the ground conductor attaches to one side. In this circuit, coupling by crossover causes amplitude and phase error of the Butler Matrix. By narrowing the strip width of the crossover, crossover coupling can be suppressed 10 dB. The measurement results of the experimental 8 x 8 Butler Matrix were +/-0.75 dB amplitude deviation, +/-9.5 degree phase deviation and VSWR of less than 1.15 within the relative bandwidth of 10% at 900 MHz band.

关键词： Butler matrix multi beam antenna adaptive array antenna beam forming network

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