Ryotaro Taniguchi’s research while affiliated with Nippon Telegraph and Telephone and other places

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Publications (34)


Proposal on Radio Propagation Prediction System Using Quantum Annealers
  • Conference Paper

November 2024

Keita Fujita

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Tetsuro Imai

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Wataru Yamada

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[...]

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Ryotaro Taniguchi



Direction of Arrival Estimation of Circular Array Using Compressed Sensing in 20-GHz Band

February 2021

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32 Reads

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15 Citations

IEEE Antennas and Wireless Propagation Letters

The super-high-frequency (SHF) band is used in the 5th generation mobile communication system (5G), and the introduction of massive multiple-input multiple-output (MIMO) to 5G is being considered. In an environment with substantial propagation loss, such as that in the case of millimeter waves, massive MIMO can realize beamforming according to the position of terminal stations. Therefore, it is important to understand the direction of arrival of millimeter waves. In this paper, we clarify the relationship between power, delay time, and direction of arrival, while focusing on the horizontal direction, using a 48-element massive array in the 20-GHz band in urban Japan. In addition, we obtain direction of arrival estimation results using an iterative reduction threshold algorithm (ISTA), which is based on compressed sensing. It is shown that the dominant path can be estimated by using the ISTA even with approximately five elements.


A simple model of outdoor to indoor penetration path-loss considering incident angles at 0.9, 2.3 and 5.1 GHz

February 2021

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38 Reads

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2 Citations

IEICE Communications Express

The fifth generation (5G) of mobile communication systems is actively being investigated worldwide. Various systems exist when considering the microwave bands after the introduction of the 5G systems. Considering microwave propagation characteristics is crucial to minimize possible interferences among systems. This study focused on the fact that wireless communication devices such as smartphones and wireless LANs are primarily used in various indoors environments. Previously, we evaluated the loss due to the difference between the incident angles of the vertical plane with respect to a window through which radio waves enter from outdoor to indoor (O2I). In the present study, we measured the loss when radio waves enter from O2I through a window in the 0.9/2.3/5.1 GHz band, where many IoT devices are expected to be used. From the data analysis of the measured results, we proposed a simple O2I penetration path-loss model using incident angles in the vertical and horizontal planes.







Citations (14)


... The authors of [17] developed a sub-THz massive multipleinput multiple-output (MIMO) channel sounder using 896 antenna elements, offering a high time-spatial channel resolution. The developed channel sounder could determine how many pathways arrived with a lower received power in real time. ...

Reference:

Transceiver Design of a Secure Multiuser FDSS-based DFT-Spread OFDM System for RIS-and UAV-assisted THz Communications
Sub-Terahertz MassiveMIMO Channel Sounder for 6G Mobile Communication Systems
  • Citing Conference Paper
  • March 2024

... Virtual MIMO technology (V-MIMO), which has been deeply studied for wireless sensor networks, can solve some problems of the traditional MIMO technology. V-MIMO technology utilizes multiple single antenna terminals, to cooperate with each other to form an effective antenna array [29]. After receiving the information forwarded by the cooperative partner, the terminal combines the signals to achieve spatial diversity gain. ...

Effectiveness of the virtual massive MIMO in 5G with OFDM
  • Citing Conference Paper
  • January 2021

... DoA-based wave source localization schemes are proposed in [5]- [7]. Takase et al. [5] propose a wave source localization scheme in LOS environments, where each path between a UAV and the wave source includes a direct path by placing the UAV at a sufficient height. ...

Source Location Estimation via Compressed Sensing using UAVs
  • Citing Conference Paper
  • January 2021

... The selection of frequencies 24 GHz and 27 GHz, which fall within the millimeter-wave spectrum [13], [14], presents notable advantages for 5G applications [15], including elevated data rates, reduced latency, TELKOMNIKA Telecommun Comput El Control  1×2 microstrip patch antennas array for mm-waves 5G application (Karima Benkhadda) 41 and expanded network capacity. Moreover, selecting these frequencies aligns with worldwide initiatives aimed at allocating spectrum for the deployment of 5G technology. ...

Direction of Arrival Estimation of Circular Array Using Compressed Sensing in 20-GHz Band
  • Citing Article
  • February 2021

IEEE Antennas and Wireless Propagation Letters

... GHz band is used as the microwave band, and the 28 GHz band is used as the millimeter wave band. For such a complex system, it requires a great deal of effort to evaluate its propagation characteristics in multiple frequency bands [1]. In this paper, we propose a method to estimate the datarate based on the received power measurement using continuous wave ("CW") signals, SNR and K-factor [2]. ...

Comparison of SNR and channel capacity with micro and milli-meter wave bands based on outdoor propagation measurement
  • Citing Article
  • January 2020

IEICE Communications Express

... To further utilize the spatial DoFs, some regular/irregular array geometries were explored with the objective of yielding a channel with equal singular values, thereby enhancing spatial multiplexing performance [8], [9]. Additionally, the potential of mechanically rotating the uniform linear array was also investigated to achieve better channel conditions [10]. ...

Novel Unmanned Aerial Vehicle Based Line-of-Sight MIMO Configuration Independent of Transmitted Distance Using Millimeter Wave
  • Citing Article
  • Full-text available
  • January 2020

IEEE Access

... In [3], the focus is on the incident angles in the horizontal plane; further, O2I factors, which show the path-loss coefficient, are presented for the 0.8, 2.2, and 4.7 GHz bands. In our previous study, we evaluated the O2I penetration path-loss characteristics at 2 and 5 GHz for different incident angles considering only the vertical plane [4]. ...

A study on outdoor to indoor penetration path loss at 2 and 5 GHz
  • Citing Article
  • September 2019

IEICE Communications Express

... In the practical viewpoint, limited statistical CSI feedback constraint was considered and machine learning based user grouping aided hybrid beamforming was proposed [18]. Further, CSI estimation elimination approach, which applies a blind adaptive array signal processing, has been proposed and its practical performance was evaluated with considering medium access control (MAC) layer overhead of IEEE802.11ac and frequency division duplex (FDD) based LTE standards [19]. ...

Evaluation of Multi-Beam Massive MIMO Considering MAC Layer Using IEEE802.11ac and FDD-LTE

Electronics

... Link adaptation in massive MIMO was analyzed from the perspective of throughput-fairness tradeoff in [11]. Authors in [12] proposed an adaptive modulation scheme which utilizes a lookup table as an index of the modulation type by using the feature of amplitude beam selection. More recently, a learning-based rate adaptation mechanism was proposed for a downlink massive MIMO with underlaid device-to-device links [13]. ...

A Study on Adaptive Modulation Method for Downlink Multi-Beam Massive MIMO
  • Citing Conference Paper
  • August 2018

... We previously proposed analog-digital hybrid massive MIMO transmission that eliminates CSI estimation by utilizing a multibeam circuit [7] [8]. In this method, the multibeam circuit is in the analog part, and multiple beams with only amplitude information in the multibeam circuit are selected according to the distribution of users [9]. Then, in the digital part, interference is cancelled using only a received signal without CSI estimation. ...

Multi-Beam Massive MIMO with Beam-Selection Using Only Amplitude Information in Uplink Channel
  • Citing Article
  • January 2018

IEICE Transactions on Communications