担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers (IEEE)  

添付ファイル： IEEE Access_Fast Double-Directional Full Azimuth Sweep Channel Sounder Using Low-Cost COTS Beamforming RF Transceivers.pdf

DOI： 10.1109/access.2021.3085325

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper reports the measurement campaign and identification results of the millimeter-wave multi-path propagation characteristics at 61.5 GHz band in a passenger vehicle environment. Four measurement scenarios were assumed, and the propagation characteristics of the dominant paths in each were identified. From the results, it can be seen that the dominant paths are distributed along the line-of-sight (LoS) direction, but it could also be seen that some other communication links of which power are ranged from 10 to 15 dB smaller than that of the LoS component are available.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In recent years, since the propagation channel characteristics have been effectively used for applications such as motion sensing, position detection, etc. A great deal of attention is attracted to channel sounding methods easy to utilize using low-cost devices. This paper presents a device-free indoor location estimation method using spatio-temporal features of radio propagation channels using the 2.4-GHz band 3-by-3 MIMO channel sounder developed using commodity wireless LANs. The measurement results demonstrated a reasonable performance of the proposed method with small number of antennas.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In the future, the importance of in-vehicle sensors will increase. The usage of wireless communications is considered to save the number of electric wires for connecting the sensors. In this paper, we show ray-tracing simulation and experimental measurement in passenger vehicle. From the comparison between simulation and measurement, it was seen that the angular path loss distributions were very similar even if the path loss of the reflected paths in measurement were about 20 dB or more larger than those of the corresponding paths in the simulation.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/twc.2020.2992533

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

The IEEE 802.11ay channel models have been developed based on the quasi-deterministic (Q-D) channel modeling that considers environment specific property of millimeter-wave (mm-wave) propagation by representing multi-path channels as superposition of deterministic (called D-ray) and random clusters (called R-ray). Based on the Q-D model, this letter presented the inter-cluster parameters of the random clusters which were obtained from the double-directional channel measurement in an indoor entrance hall environment. Comparison between the parameters obtained in this study and those of the existing IEEE 802.11ay/MiWEBA model showed that both are reasonable values inferred from each corresponding environment.

DOI： 10.1587/comex.2020XBL0052

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electronics, Information and Communications Engineers (IEICE)  

In radio channel measurements and modeling, directional scanning via highly directive antennas is the most popular method to obtain angular channel characteristics to develop and evaluate advanced wireless systems for high frequency band use. However, it is often insufficient for ray-/cluster-level characterizations because the angular resolution of the measured data is limited by the angular sampling interval over a given scanning angle range and antenna half power beamwidth. This study proposes the sub-grid CLEAN algorithm, a novel technique for high-resolution multipath component (MPC) extraction from the multi-dimensional power image, so called double-directional angular delay power spectrum. This technique can successfully extract the MPCs by using the multi-dimensional power image. Simulation and measurements showed that the proposed technique could extract MPCs for ray-/cluster-level characterizations and channel modeling. Further, applying the proposed method to the data captured at 58 :5 GHz in an atrium entrance hall environment which is an indoor hotspot access scenario in the fifth generation mobile system, the multipath clusters and corresponding scattering processes were identified.

DOI： 10.1587/transcom.2019ebp3055

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electronics, Information and Communications Engineers (IEICE)  

DOI： 10.1587/transcom.2019hmp0005

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/access.2020.2991044

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electronics, Information and Communications Engineers (IEICE)  

DOI： 10.1587/comex.2019xbl0093

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IET  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electronics, Information and Communication, Engineers, IEICE  

In order to utilize higher frequency bands above 6 GHz, which is an important technical challenge in fifth generation mobile systems, radio propagation channel properties in a large variety of deployment scenarios should be thoroughly investigated. The authors' group has been involved in a fundamental research project aimed at investigating multipleinput- multiple-output (MIMO) transmission performance and propagation channel properties at microwave frequency above 10 GHz from 2009 to 2013, and since then they have been conducting measurement and modeling for high frequency bands. This paper aims at providing comprehensive tutorial of a whole procedure of channel modeling
multi-dimensional channel sounding, propagation channel measurement, analysis, and modeling, by introducing the developed MIMO channel sounders at high frequency bands of 11 and 60 GHz and presenting some measurement results in a microcell environment at 11 GHz. Furthermore, this paper identifies challenges in radio propagation measurements, and discusses current/future channel modeling issues as future works.

DOI： 10.1587/transcom.2017ISI0003

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers Inc.  

To resolve the crowded radio spectrum problem observed in conventional microwave bands (below 6 GHz), new frequency bands higher than 6 GHz are being considered to facilitate the use of a much wider bandwidth for next-generation wireless systems. Various channel sounding measurements have been conducted to elucidate the radio propagation properties at such new frequency bands. For a high-frequency channel sounding measurement, directional scanning with high-gain antennas is a popular method adopted to save the development cost of a full antenna array. This letter presents the analysis of the maximum likelihood multipath component parameter estimation accuracy where a Gaussian beam antenna pattern obtained by the scaled von Mises distribution function is used for the ease of analysis. The numerical analysis shows that the angle estimation error is approximately proportional to the square of the antenna half-power beamwidth (HPBW) and the square root of the angular sampling interval (ASI), respectively, and the amplitude and phase estimation error is approximately proportional to the HPBW and the square root of the ASI, respectively. The intrinsic performance of the used antenna is also discussed.

DOI： 10.1109/LAWP.2017.2768434

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

This paper presents a clustering and tracking method that exploits the geometry of the scattering points (SPs) obtained from the measurement-based ray tracer. The multipath components (MPCs) were categorized into clusters by applying the KPowerMeans (KPM) framework to those SPs. The clusters were tracked by comparing the cluster-centroid SPs of the adjacent snapshots. The clusters were estimated based on the indoor environment geometry at 11 GHz, and their physical mechanisms were interpreted. The complexity and performance of this method was assessed and compared with that of conventional KPM by comparing the number of floating point operations (FLOPS) and the channel eigenvalues obtained from the reconstructed channel matrices, which were calculated by superposing the MPCs randomly generated from intracluster parameters. The verification of this method showed that most clusters were estimated and tracked according to the physical location of the scatterers in the environment with acceptable error. Moreover, the eigenvalues reconstructed from the proposed method were closer to the measured ones with less number of FLOPS, which indicates both accuracy and complexity improvement. The results also imply that multiple-input multiple-output performance is highly dependent on the radio propagation channel; therefore, it is imperative that clusters in the channel be determined accurately.

DOI： 10.1109/TAP.2017.2754417

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記述言語：英語  

DOI： 10.1109/TAP.2017.2728087

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

To use millimeter wave bands in future cellular and outdoor wireless networks, understanding the multipath cluster characteristics such as delay and angular spread for different polarization is very important besides knowing the path loss and other large scale propagation parameters. This paper presents result from analysis of wide-band full polarimetric double directional channel measurement at the millimeter wave band in a typical urban pico-cell environment. Only limited number of multipath clusters with gains ranging from -8 dB to -26.8 dB below the free space path loss and mainly due to single reflection, double reflection and diffraction, under both line of sight (LOS) and obstructed LOS conditions are seen. The cluster gain and scattering intensity showed strong dependence on polarization. The scattering intensities for v - v polarization were seen to be stronger compared to phi - phi polarization and on average 6.1 dB, 5.6 dB and 4.5 dB higher for clusters due to single reflection, double reflection and scattering respectively. In each cluster, the paths are highly concentrated in the delay domain with delay spread comparable to the delay resolution of 2.5 ns irrespective of polarization. Unlike the scattering intensity, the angular spread of paths in each cluster did not show dependence on polarization. On the base station side, average angular spread in azimuth and in elevation were almost similar with <= 3.3 degrees spread in azimuth and <= 3.2 degrees spread in elevation for v - v polarization. These spreads were slightly smaller than those observed for phi - phi polarization. On the mobile station side the angular spread in azimuth was much higher compared to the base station side. On average, azimuth angular spread of <= 11.4 degrees and elevation angular spread of <= 5 degrees are observed for v - v polarization. These spreads were slightly larger than in phi - phi polarization. Knowing these characteristics will be vital for more accurate modeling of the channel, and in system and antenna design.

DOI： 10.1587/transcom.2016EBP3303

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Body area network (BAN) is a fundamental technology to realize future ICT-based healthcare services and applications, where channel modeling plays an important role in designing more reliable BAN systems. The greatest challenge of the WBAN channel modeling is that the antennas operate in proximity to the human body. Near-field interactions between the antenna and the human body make it difficult to distinguish the contribution of the antennas within the channel response, i.e., the antennas are embedded in the channel. As a result, the characterized channels had to be always specific to the given antenna, and antenna optimization is difficult. Therefore, this paper proposed antenna deembedding by applying the spherical wave function channel modeling into the on-body channel. The finite-difference time-domain (FDTD) method was utilized to implement the concept. The proposed implementation was validated against the conventional antenna-embedded simulation. Furthermore, the antenna performance evaluation in terms of mean path gain during a specific body motion was demonstrated as an application. The simplified but practical version of the proposed approach, involving only the fundamental modes, was introduced. The obtained mean path gain was compared with the measurement.

DOI： 10.1109/TAP.2017.2655006

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Recently, the fifth-generation mobile communication system (5G) has been widely investigated to accommodate increasing mobile users' traffic. In the 5G system, although the utilization of the higher frequency band above the 6 GHz band is expected, the detailed investigation for the applicability to the mobile communication is still necessary because of different radio channel characteristics compared with microwave bands. In this paper, 11 GHz band MIMO channel measurements were conducted in a street micro-cell environment. The result shows that the delay and the angular spreads of the specular paths were smaller compared with the results in the microwave band. The scattered signal component was weak compared with measurement results of indoor environments. The result is expected to utilize for the MIMO channel modeling in the higher frequency band.

DOI： 10.23919/EuCAP.2017.7928473

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In order to utilize higher frequency bands above 6 GHz which is an important technical challenge in fifth generation mobile systems and ultra-high speed WLANs, radio propagation channel properties in large variety of deployment scenarios should be thoroughly investigated. This paper presented measurement results in an atrium entrance hall environment at an millimeter-wave band of 58.5 GHz assuming an indoor hotspot access scenario. In this measurement, the channel transfer functions of a wideband signal with 400 MHz bandwidth were measured by rotating high gain horn antennas with 12 and 30 degree half power beamwidth at 25 receiver positions. From the measured double-directional angular delay power spectrum, the multi-path clusters were roughly identified by local peak detection. This paper presented delay and angle domain intercluster characteristics and identified the propagation mechanism of each cluster comparing with ray tracing simulation. The measurement results revealed that the dominant mechanisms of the multi-path clusters are the first-order specular reflection from environment specific large walls and scattering by columns and square pillars.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In this paper, a novel approach of a human motion classification system in wireless body area network (WBAN) using received radio signal strength was developed. This method enables us to classify human motions in WBAN using only the radio signal strength during communication without additional tools such as an accelerometer. The proposed human motion classification system has a potential to be used for improving communication quality in WBAN as well as recording daily-life activities for self-awareness tool. To construct the classification system, a numerical simulation was used to generate WBAN propagation channel in various motions at frequency band of 403.5MHz and 2.45 GHz. In the classification system, a feature vector representing a characteristic of human motions was computed from time-series received signal levels. The proposed human motion classification using the radio signal strength based on WBAN simulation can classify 3-5 human motions with the accuracy rate of 63.8-95.7 percent, and it can classify the human motions regardless of frequency band. In order to confirm that the human motion classification using radio signal strength can be used in practice, the applicability of the classification system was evaluated by WBAN measurement data.

DOI： 10.1587/transcom.2015MIP0009

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper presented an outdoor-to-indoor (O2I) channel measurement result at 58.5 GHz assuming an outdoor hotspot access scenario in 5G mobile systems and WLANs. Comparing the measurement results with ray-tracing (RT) simulation, dominant propagation mechanisms were identified. From the analysis, the propagation mechanism of eight multipath clusters were identified.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

To use millimeter wave bands in future cellular and wireless networks, characterization of the radio propagation channel in outdoor urban small cell or pico cell environment is vital. In this paper we present results from analysis of wideband full polarimetric directional channel measurements in an urban pico-cell environment using the double directional millimeter wave channel sounding system we developed. Multipath clusters with excess gain ranging from -9.6 dB to -22 dB in both line of sight (LOS) and obstructed LOS cases are seen. The most significant clusters were due to first and second order reflection, and diffraction. The clusters ranged from being highly specular in nature with very small (nearly 0 degrees) angular spread to having angular spreads of up to 5.8. in azimuth and 6.3. in elevation. Similarly the delay spread of the clusters ranged up to 2.1 ns.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper presented dominant propagation mechanisms in an outdoor open area environment through the channel measurement and ray-tracing (RT) simulation at an mm-wave band of 58.5 GHz assuming an outdoor hotspot access scenario in 5G mobile systems and WLANs. From the data analysis, multi-path clusters by first- and second-order reflection, first order diffraction and scattering mechanisms were identified. The measurement result revealed that the multi-path clusters have relatively small power less than approximately 20 dB to the direct path other than first-order reflection from nearby buildings that can be predicted in a deterministic manner, and the channel can he well expressed by the quasi-deterministic (Q-D) channel model which supports natural description of environment-specific deterministic components separately from the other random components. Based on Q-D model, this paper presented extracted statistical channel model parameters of the random components by using RT simulation.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In next-generation mobile communication systems, utilization of higher frequency bands above 10 GHz has become a hot research topic because it has the potential to improve network capacity drastically by utilizing the available wideband spectrum. However in the higher frequency bands, in addition to the higher propagation loss, diffuse scattering of propagation wave is thought to affect the multiple-input multiple-output (MIMO) channel characteristic more significantly. In this paper, 11 GHz band MIMO channel measurements were conducted in a line-ofsight (LoS) indoor environment to clarify the characteristics of diffuse scatterings in the higher frequency band. The frequency, angular, and the polarization domain dense multipath component (DMC) propagation parameters were estimated by using the RiMAX-based estimator. The measurement result shows that there was a significant DMC due to diffuse scatterings from the floor and the ceiling. The DMC had directional and polarization dependencies that were different from the RiMAX DMC model. The result is expected to be utilized for the novel MIMO channel model proposal in the higher frequency band that includes the DMC contribution.

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記述言語：日本語   出版者・発行元：公益社団法人 日本生体医工学会  

<p>Wireless body area network (WBAN) is a wireless sensor network inside, on or around the human body, and is expected to be utilized in medical and health-care applications. Dynamic behavior of radio propagation channel is important information for design and characterization of WBAN system. Various factors simultaneously influence the channel responses, such as position and orientation of antennas, electromagnetic interaction antenna and human body, and obstruction by human body itself. Therefore, it is rather difficult to analyze the propagation mechanism of dynamic WBAN channel. This paper reports the development of simultaneous measurement system of MIMO channel response and body posture of dynamic WBAN channel. Body posture information is utilized to synthesize numerical phantom for electromagnetic simulation via computer animation software. Comparison between measurement and predicted channel responses is possible by using the system, and some examples will be presented.</p>

DOI： 10.11239/jsmbe.54Annual.S79

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

For designing reliable wireless body area network (WBAN) systems, channel modeling plays an important role. Antenna de-embedding, in which the contribution of antennas is separately modeled from the channel, has been one of the biggest challenges in WBAN channel modeling. While the antenna de-embedding in mobile communication has been achieved by double-directional channel modeling, this approach can not be applied to the WBAN channel because the antennas are operating close to the human body. Instead, this paper evaluates an antenna de-embedding scheme using spherical-wave-functions (SWFs). The antennas are modeled by the spherical wave coefficients. The channel without the antennas is modeled by a mode-to-mode mapping matrix M which describes the relationship between the radiated and impinging spherical waves. This paper shows the numerical validation of the transmit antenna model. The E-field distribution throughout the region is successfully reproduced by the antenna model in the proposed approach.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper proposes novel clustering approach which utilizes scattering points obtained from the measurement-based ray tracer (MBRT). After that, multipath components (MPCs) were classified into clusters according to those scattering points, the performance of this algorithm was evaluated with 11 GHz channel sounding data in an indoor environment. The evaluation results showed that the MPCs were classified into the clusters and the cluster centroids were tracked accurately by utilizing the physical locations of MPCs in the proposed method.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper investigates a transmission power control scheme based on the context-specific temporal correlation model in WBAN. Firstly construction of the context-specific temporal correlation model is presented. After that a channel estimation method using the last known channel gain and the constructed temporal correlation model is explained. The channel estimation is then used in our proposed transmission power control scheme, that determines the transmit output power of each transmission. Performance of the transmission power control is illustrated using the Castalia simulator. A guideline of parameter tuning that trades off between communication reliability and energy consumption is also given. Furthermore, the effectiveness of the transmission power control scheme is compared to the fixed transmit power at -5 dBm. From the simulation results, applying the transmission power control scheme reduced the energy consumption up to 12.4 percent and yielded a slightly higher packet reception rate when the packet rate was not oversaturated. When the packet rate was oversaturated, the transmission power control scheme reduced 14.2 percent of the energy consumption with less than 0.06 percent of increase in a packet error rate.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Propagation channel of body area networks fluctuates by shadowing caused by human movement. However, to make dynamic BAN channel model for individual human motion by few parameters is not easy, so most of the channel modeling in BANs are performed with statistical treatment of human motions. In this paper, as an attempt to treat individual human motions in BAN channel modeling, a geometrical modeling method of shadowing during human movement is proposed. Shadowing between on-body nodes and an external access point during several human movements (walking, running, and weak-walking) is calculated by numerical simulations, and shadowing rates are modeled by proposed method. As a result, fittings of shadowing by proposed function are obtained with six parameters for individual human movements.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electronics, Information and Communication Engineers  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

This paper proposes a novel approach to extracting the narrowband propagation channel from the communication link by de-embedding the impact of the antennas. In the proposed approach, the mode-to-mode mapping matrix M, which is the expression of the propagation channel in the spherical vector wave domain, is estimated by applying pseudo-inverse computation to the channel transfer functions with dedicated spherical arrays. The estimated M is truncated and only the dominant modes within the spatial bandwidth of the fields radiated from the finite volume of the spherical array are considered. Two types of spherical array are investigated: 1) an ideal array using tangential dipoles; and 2) a virtual array using dielectric resonator antenna (DRA). The ideal array is used for parameter investigation including the array radius and the spacing with regard to the size of M and the condition number of the excitation coefficient matrix, while the virtual DRA array is proposed as a practical implementation of the ideal array. The accuracy of the proposed approach has been validated numerically. The uncertainties of spherical array in practice, such as the influence of nonideally embedded array elements, cables, and fixtures, are considered in the validation. Moreover, the channel transfer functions reproduced by the de-embedded M are analyzed, given different target antennas at link ends. The gain and phase discrepancies as well as the antenna correlations of the reproduced channel transfer function are compared with the generated reference.

DOI： 10.1109/TAP.2015.2443854

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Finite-difference time-domain (FDTD) method is one of the promising approaches for the propagation prediction. However, since the computational domain includes both the antennas and the propagation environment, their coupling prevents evaluating individual contributions to the channel response. As a result, the simulation becomes always specific to the given antenna type or orientation and cannot be reused for other configurations. The simulation also requires the internal structure of the antenna which is often unavailable and/or difficult to be modeled. These problems can be addressed by antenna de-embeddeding which separatelymodels the antenna and the propagation environment, hence the purpose of this paper. In particular, this paper proposes the implementation of spherical-wave-function (SWF) channel modeling using the FDTD method. Instead of modeling the real antenna structures inside the computational domain, the single-mode spherical wave source and the observation points are utilized. The spherical wave source is achieved by a cubical dipole array. The spherical wave source is first validated, including the investigation of the effects of cell and array size. The narrow-band channel response synthesized by the proposed approach is then validated numerically through comparison with the transmission formula in free space and the conventional antenna-embedded simulation in the human shadowing environment as well.

DOI： 10.1109/TAP.2015.2414442

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

To improve the outage performance of a wireless body area network (BAN), exploitation of the diversity in the channel obtained by letting different nodes cooperate and relay signals for each other is an attractive solution. We carry out multi-link channel measurements and modeling for all realistic locations of the on-body sensor nodes and for three different motion scenarios in a typical office environment to develop equivalent channel model for simple and practical cooperative transmission schemes. Using the developed model the performance of the transmission schemes are evaluated and compared. Incremental decode and forward relaying is found to be consistently better than the other schemes with gains of up to 16 dB at 10% outage probability, and an average gain of more than 5.9 dB for any location of the coordinator node. The best location of the coordinator node based on the performance is also determined. Such insights will be very useful in designing BANs.

DOI： 10.1587/transcom.E98.B.554

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Wireless body area networks (WBANs) are an emerging technology for realizing efficient healthcare and remote medicine for the aging society of the future. In order to improve the reliability of WBAN systems and support its various applications, channel modeling and performance evaluation are important. This paper proposes a simulation-based channel modeling for evaluating the performance of WBAN cooperative transmission schemes. The time series of path losses among seven on-body nodes are generated by the finite-difference time-domain method for seven body motions. The statistical parameters of the path loss for all the motions are also obtained. The generated path loss is then applied to the evaluation of the two-hop decode-and-forward relaying scheme, yielding an improvement in transmit power. From the evaluation of body motion, useful insights are obtained such as which relay links are more robust than others. Finally, the proposed approach is validated through comparison with a measurement-based approach.

DOI： 10.1109/JBHI.2014.2326424

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper investigates the dominant propagation mechanisms in indoor line-of-sight (LOS) environments from channel measurement and ray tracing simulation. Double-directional channel sounding was performed using 24x24 multiple-input multiple-output (MIMO) channel sounder at 11 GHz with 400 MHz bandwidth to get the MIMO channel transfer function. Path parameters from ray tracing simulation and antenna array response were used to reconstruct the ray tracing based channel transfer function. Beamforming was applied to both channel transfer functions to get angle resolved power spectrum. Then the angular and delay power spectra were used to identify the dominant propagation mechanisms. Along with LOS component, walls and window reflected paths were found to be the dominant propagation mechanisms observed in both measurement and simulation. But ray tracing failed to predict the scattering power from the long and thin metal objects such as window frame and metal pillar edge which are the significant objects observed in measurement.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper presents a wideband full polarimetric directional channel measurement results at 58.5 GHz in a small office room environment assuming an indoor access-point (AP) scenario in the next generation mobile systems. The delay resolution was 2.5 ns from the signal bandwidth of 4100 MHz, and the double directional angular characteristics were achieved by rotating high gain horn antennas at both sides of transmitter and receiver. By identifying scattering objects from the measurement data analysis, some important observation about the channel properties were reported. The results reveal that there were a few number of dominant specular multipath components of which the relative power to that of the direct path ranged between -8 and -13 dB. It was also observed that the depolarization is not significant in most of the detected paths with cross-polarization ratio of larger than 14 dB.

DOI： 10.1109/PIMRC.2015.7343400

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

High frequency spectrum is expected to offer a wide bandwidth for future broadband cellular networks. This paper presents the measurement results of the outdoor urban cellular wideband channels at 11 GHz. The measurements at various urban cellular environments that are classified into macrocell, microcell and street-cell were conducted, where a wideband 24 x 24 MIMO channel sounder having 400 MHz signal bandwidth and dual-polarized 12-element uniform circular arrays were used. This paper presents large scale characteristics of 11 GHz wideband channels including path losses, shadowing, cell coverage, polarization properties and delay spread, which were calculated by the polarimetric beamforming both at transmitter and receiver. Large shadowing loss of approximately 20 dB was observed in NLoS condition, and from the outage calculation it was seen that the cell coverage with omni-directional antennas is limited to less than 100 m for 30 dB SNR. From the power delay profile (PDP), small RMS delay spreads with the mean value of less than 20 ns were observed.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

To design sufficiently reliable wireless body area network (WBAN) system for future health-care, channel modeling plays an important role. Especially from the viewpoint of antenna optimization, the channel modeling approach should be able to de-embed the antenna contribution to the channel response. Two modeling approaches using spherical wave functions (SWFs) and orthogonal dipoles (ODs) have been proposed so far for this purpose, and the simplified form of the SWF channel modeling involving only fundamental modes is equivalent to OD channel modeling. Although the modeling by SWF fundamental modes or the ODs is practical, the accuracy of their channel approximation should be clarified in advance, hence the purpose of this paper. For the analysis of the accuracy, deviated dipole is utilized to model the antennas in finite size which can emit the higher modes. Applying the finite-difference time-domain method to the deviated dipole and the animated human body, the approximated and the exact channel response are obtained. The error due to the approximation is then modeled by log-normal distribution, of which statistical parameters are empirically obtained as the function of either the antenna size or residual power.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Wireless body area network (WBAN) is expected to be utilized in various fields such as health-care. One of its vital challenges is that dynamic channels suffer severely from fading. Therefore the characterization of WBAN channel is important and many researches have been done in this area. This paper presents a tri-polarized dynamic WBAN channel sounder to realize 3x3 dynamic channel measurement by applying time division multiplexing (TDM), and by using two tri-polarized dielectric resonator antennas (DRAs) and a multi-port oscilloscope. Due to the tri-polarized property of DRA, this present system can contribute to the antenna polarization dependency of WBAN channel as well as the measurement-based antenna de-embedding. In this paper, system configuration, parameter design, DRA antenna, calibration method, and measurement validation are presented.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE  

Copyright © 2014 The Institute of Electronics, Information and Communication Engineers. This paper presents a 24 x 24 MIMO channel sounder that has been developed based on a scalable fully parallel MIMO architecture. It can be flexibly configured with 3 sub-transmitters and 3 sub-receivers, each of which consists of 8 RF ports. This flexibility allows the measurement for both purposes of double directional and multi-link MIMO channel measurements. Implementation issues related to the multi-link operation on the fully parallel architecture were successfully solved by appropriate system design and applying several calibration techniques. The performance of the developed system was validated by extensive test experiments. Finally, a multi-link channel measurement example in an indoor environment was presented demonstrating the capability of the proposed system.

DOI： 10.1587/transele.E97.C.994

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This paper presents a 24 x 24 MIMO channel sounder that has been developed based on a scalable fully parallel MINI architecture. It can be flexibly configured with 3 sub-transmitters and 3 sub-receivers, each of which consists of 8 RF ports. This flexibility allows the measurement for both purposes of double directional and multi-link MIMO channel measurements. Implementation issues related to the multi-link operation on the fully parallel architecture were successfully solved by appropriate system design and applying several calibration techniques. The performance of the developed system was validated by extensive test experiments. Finally, a multi-link channel measurement example in an indoor environment was presented demonstrating the capability of the proposed system.

DOI： 10.1587/transele.E97.C.994

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

This paper presents the large scale parameters of wideband multipath channels based on extensive measurement campaigns in various indoor environments. The measurements were conducted with a wideband multiple-input multiple-output (MIMO) channel sounder having a bandwidth of 400 MHz at 11 GHz which is a challenging frequency for future mobile systems. In particular, polarization characteristics of path-loss, shadowing, cross-polarization power ratio (XPR), delay spread and coherence bandwidth are characterized. The measurement results show that the path-loss exponents range between 2.0 and 3.0 for none-line-of-sight (NLoS), 0.36 and 1.5 for LoS, respectively. Vertically and horizontally polarized transmissions have almost same path-gain, but in some corridor-room NLoS environments, the path-loss for HH is significantly large. In most cases, the RMS delay spreads are less than 20 and 50 ns for NLoS and LoS, respectively, and the average coherence bandwidth is less than 30 MHz. The Rician K-factors range between 2 and 3 dB for cross-polarization, and in large Hall environments, those for co-polarization are greater than 6.0 dB with 10% probability. Finally, some dominant propagation mechanism and site-specific behaviors are illustrated using the double-directional measurement results.

DOI： 10.1109/TAP.2013.2288633

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Body area network (BAN) has gained a lot of attention in last the few years due to the huge opportunities for application in fields such as healthcare and patient monitoring, sports, military, space applications, business and entertainment among others. In general a BAN node has to be compact, comfortable and safe to be worn by the subject for long durations, while being reliable at the same time. The nodes therefore need to be highly energy efficient and operate at low transmit power. However on the other hand, at low transmit power BAN could suffer from serious reliability issues because of the large attenuation caused by body, body motion and the environment. Additionally a BAN channel is found to be quasi-static nature [1]; BAN channels are composed of dominant slow fading components such that during the packet transmission the channel effectively remains constant, resulting in burst errors that are difficult to be corrected by the simple error correction codes recommended in the BAN standard [2]. Narrowband BAN will also suffer from reliability issues due to interference from other wireless systems such as wireless LAN, Bluetooth and ZigBee with which it has to coexist. In this work cooperative relaying is proposed to improve the outage performance of on-body BAN.2-hop relaying is already recommended and included as an option in the BAN standard There are already few works on two hop cooperative relaying, although most of the existing works are based on only single hop channel measurements and fixed cooperative relaying. Knowing that BAN channels are highly influenced by the relative position of the nodes (or antennas) on the body, the body motion, posture and the surrounding environment, to better understand the possible gains due to cooperative relaying we made simultaneous multi-link channel measurement for all realistic biomedical sensor locations on the body, when the subject covered regular everyday motion scenarios in a typical office environment. Using the measurement and the narrowband PHY layer specifications of the BAN standard, we constructed equivalent 1-hop channel models for three cooperative relaying schemes; simple decode-and-forward (S-DF), cooperative decode-and-forward (C-DF), and incremental decode-and-forward (I-DF) relying. Incremental decode-and-forward relaying, the non-regenerative equivalent of which is proposed in [3], has not been discussed in the context of BAN in existing literature to the best of our knowledge.Knowing the statistics of the equivalent 1-hop channel, the outage probabilities of the three cooperative relaying schemes were then compared to the direct transmission for all possible combinations of source, cooperator and destination node. It was found that at 10% SNR outage probability I-DF relaying provided the greatest improvement in the outage threshold, with up to 16 dB improvement when the best cooperator was chosen. The statistically best coordinator or hub node location in the recommended star topology was also determined based on the gains. On average for any coordinator node location cooperative relaying always provided a net average improvement in the outage threshold, with minimum of more than 5 dB in case of the I-DF relaying. Although more realistic considerations based on actual BAN hardware would be needed to analyze the actual gains in energy due to cooperative relaying, we have demonstrated that the outage performance can be greatly improved by implementing cooperative relaying.

DOI： 10.1587/transcom.E98.B.554

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This work presents spatio-temporal channel characterization of various urban cellular environments at 11 GHz which is a challenging frequency for future high bit-rate mobile communications.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Techniques such as triangulation and trilateration have been used along with RSSI, TDOA etc. for localization in outdoor scenarios. However in densely urban areas where many obstacles exist, multipaths are dominant resulting in the above techniques to be unreliable. Fingerprint-based localization may prove to be advantageous in these scenarios [1]. Location fingerprints should be collected from as many areas as possible, but this is not feasible due to time and space constraints. One approach to solve this problem is to perform spatial interpolation on the collected fingerprints to estimate the fingerprint at an arbitrary location. This research aims to provide insight on effect of the fingerprint collection intervals on estimation accuracy by performing Monte Carlo simulations under various urban environments and conditions.
Popular spatial interpolation techniques include linear interpolation, nearest-neighbor interpolation and spline interpolation. In this research, we compare a technique called Kriging [2], which is a commonly used technique in the field of geostatistics, with several other common interpolation techniques.
The basic idea behind Kriging-based spatial interpolation is to apply weights to already observed values at surrounding locations, and the weights are calculated according to spatial covariance values. It is assumed that propagation characteristics from points located close to each other have higher correlation than points located far away from each other. Therefore, the spatial covariance will be a decreasing function over distance, and Kriging will apply larger weights to observed values located close to the interpolation point. In Kriging, it is assumed that the observed values (fingerprints) can be expressed as the summation of a constant local mean and the residual. The expectation of the residual is assumed to be zero, and covariance of the residual between two locations is assumed to be stationary and only a function of distance.
The whole interpolation process can be divided into several steps. The first step is to estimate the spatial covariance function from observed location fingerprints. Then second step is to fit the estimated covariance function with some basic covariance models. Finally, weights are calculated by solving a set of linear equations based on the covariance model obtained in the previous step.
In this research, we propose and compare several variants of Kriging which may be able to capture the spatial correlation structure of the environment more accurately. The channel impulse response (CIR) and RSSI are utilized as location fingerprints. Ray-tracing simulation is conducted to obtain location fingerprints at various urban environment scenarios. Then the estimation error of several spatial interpolation algorithms is compared with respect to several factors such as fingerprint collection interval and robustness against multipath fading.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper proposes a new clustering method by using scattering points obtained from the measurement-based ray tracer (MBRT). Wideband MIMO channel sounder was used to measure propagation path in indoor environments. The parameters of multipath components (MPCs) were extracted by the space-alternating generalized expectation-maximization (SAGE) algorithm. Comparison between traditional and new clustering method by altering the parameter vector inputted into KPowerMeans algorithm (KPM) was carried out to assess the performance by using several cluster validity indices (CVIs). Simulation results suggest that the proposed method has a better performance than traditional algorithm.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The event-driven network simulator NS-2 does not support frequency hopping (FH) and multi-channel operations, as well as the adjacent channel interference (ACI), in its current form. This paper introduces the key implementation methods to enable FH mobile ad hoc network (MANET) simulations in NS-2. The proposed simulator provides proper analysis in arbitrary topologies of FH-MANET.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

For designing reliable and low-power wireless body area network (WBAN) systems, channel modeling plays an important role. However, coupling between antennas and a human body hinders from separately modeling their individual contributions. Therefore, this paper proposes an antenna de-embedding scheme that is based on the channel modeling by means of spherical wave functions (SWFs). A preliminary validation is also presented.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Automatic modulation classification (AMC) is an important function of radio surveillance systems in order to identify unknown signals. Many previous works on AMC have utilized signal cyclostationarity, particularly spectral correlation density (SCD), but many of them fail to address several implementation issues, such as the assumption of perfect knowledge of the symbol rate. In this paper, we discuss several practical issues, e.g. cyclic frequency mismatch, which may affect the SCD, and propose compensation techniques to overcome those issues. We also propose a novel feature extraction technique from the SCD, which utilizes the SCD of not only the original received signal, but also the squared received signal. A symbol rate estimation technique which complements the feature extraction is also proposed. Finally, the classification performance of the system is evaluated through Monte Carlo simulations using a wide variety of modulated signals, and simulation results show that the proposed technique can estimate the symbol rate and classify modulation with a probability of above 0.9 down to SNRs of 5 dB.

DOI： 10.1587/transcom.E96.B.1158

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Automatic modulation classification (AMC) involves extracting a set of unique features from the received signal.. Accuracy and uniqueness of the features along with the appropriate classification algorithm determine the overall performance of AMC systems. Accuracy of any modulation feature is usually limited by the blindness of the signal information such as carrier frequency, symbol rate etc. Most papers do not sufficiently consider these impairments and so do not directly target practical applications. The AMC system proposed herein is trained with probable input signals, and the appropriate decision tree should be chosen to achieve robust classification. Six unique features are used to classify eight analog and digital modulation schemes which are widely used by low frequency mobile emergency radios around the globe. The Proposed algorithm improves the classification performance of AMC especially for the low SNR regime.

DOI： 10.1587/transcom.E96.B.1030

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In this paper, the measurement results of indoor wideband MIMO channels at 11 GHz will be presented. The path loss and delay spread for different polarizations will be shown and the empirical models will be presented as well. Then, the channel capacity of the dual polarized MIMO configuration will be evaluated.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

This paper proposes a parametric method of frequency-dependent I/Q imbalance compensation for wideband quadrature modulators using the spectrum measurement of a radio frequency (RF) signal that is easily performed by a general-purpose spectrum analyzer. The proposed method empirically estimates the frequency-dependent circuit parameters using only the magnitude of the frequency spectrum of the RF signal that is fed back from the spectrum analyzer. The frequency dependency of the I/Q imbalance effect generated by the difference between the overall frequency responses of the I and Q branches is modeled by frequency-dependent circuit parameters. By dividing the entire signal band into several sub-bands, the transmit signals are predistorted per sub-band in the frequency domain. To estimate the frequency-dependent circuit parameters, in this study, the modified method of steepest descent developed for single-band compensation is extended to the frequency-domain sub-band compensation scheme. We demonstrate the compensation effect by implementing an automatic sub-band circuit parameter estimation system. © 2012 IEEE.

DOI： 10.1109/TMTT.2012.2228215

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

The WBAN on-body multi-link radio channels at 2.4 GHz were investigated. A wearable channel sounding system using commercial off-the-shelf Zigbee radios capable of continuous, prolonged and synchronized measurement has been developed. The measured channels were statistically analyzed to identify the potential cooperator nodes for two hop relaying in a star topology WBAN. This will be useful in designing relaying and cooperative communication schemes for improving the reliability of a WBAN under various channel fading conditions. Significant performance gain for two hop link, with the selected cooperator node, over the direct link in terms of outage rate is demonstrated.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Study of the radio propagation channel is essential to design a reliable wireless system, especially in the Body Area Network (BAN) which will be used for medical/healthcare purposes. In the simulation of the BAN channel, various postures and motions of the human body should be examined for robustness. However, generating this motion data consumes time and is costly since experience with 3D animation software or complex motion capture systems with multiple cameras is required. Therefore, this paper proposes the utilization of Kinect, a motion capture gaming device, for the BAN channel simulation. The data from Kinect, namely the series of joints, depth, and image are converted into series of voxel models. Then, finite-difference time-domain (FDTD) simulation using the generated voxel models is performed.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

This paper presents a novel multiple-input-multiple-output (MIMO) channel sounding technique with a fully parallel transceiver architecture that employs a layered scheme of frequency and space-time division multiplexing. It offers inherent scalability of the number of antennas by a combination of multiple transceiver units and flexibility for both directional MIMO channel and multi-link MIMO channel measurements. This paper describes the principle of the channel sounding technique and formulates the signal processing that makes possible various scalable unit configurations. The influence of the transceiver imperfections such as I/Q imbalance (IQI) and phase noise (PN) on the measurement accuracy is discussed, and a multitone allocation scheme that is robust against IQI is also introduced. Using computer simulations, the measurement accuracy in the presence of IQI and PN is evaluated using the normalized mean square error, which provides a design guideline for the realization of hardware.

DOI： 10.1109/TIM.2012.2205510

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Body area network is an emerging area of wireless communication for medical healthcare applications. This paper characterizes the narrowband wireless on-body channels under specific action scenarios by measurement at the three different sub-GHz frequencies of 444.5, 611, and 953 MHz, which are the candidate frequency bands of narrowband body area network systems with low data rates in IEEE 802.15.6 standard. The channel responses at ten different antenna positions were measured in an office room environment for the two dynamic action scenarios of "walking on the spot" (Action I) and "standing up/sitting down" (Action II). This paper provides generalized on-body channel models of Nakagami- and Weibull distributions for Actions I and II, respectively. Notably, this paper shows that the shadowing effect due to body movement is dominant over the multipath fading. The results were obtained by the statistical analyses of channel fading properties at three different frequencies including level crossing rate, average fade duration and channel dwelling time.

DOI： 10.1109/TAP.2012.2207937

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This letter proposes an automatic IQ imbalance compensation technique for quadrature modulators by means of spectrum measurement of RF signal using a spectrum analyzer. The analyzer feeds back only magnitude information of the frequency spectrum of the signal. To realize IQ imbalance compensation, the conventional method of steepest descent is modified; the descent direction is empirically determined and a variable step-size is introduced for accelerating convergence. The experimental results for a four-channel transmitter operating at 11 GHz are presented for verification.

DOI： 10.1587/transcom.E95.B.1864

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Spectrum sensing, a key technical challenge in cognitive radios (CR) technology, is a technique that enables the spectrum of licensed systems to be accessed without causing undue interference. It is well known that cyclostationarity detectors have great advantages over energy detectors in terms of the robustness to noise uncertainty that significantly degrades the performance as well as the capability to distinguish the signal of interest from the other interferences and noise. The generalized likelihood ratio test (GLRT) is a recognized sensing technique that utilizes the inherent cyclostationarity of the signal and has been intensively studied. However, no comprehensive evaluation on its performance enhancement has been published to date. Moreover high computational complexity is still a significant problem for its realization. This paper proposes a maximum ratio combining multi-cyclic detector which uses multiple cyclic frequencies for performance enhancement with reduced computational complexity. An orthogonal frequency-division multiplexing (OFDM) signal based on the ISDB-T (integrated services digital broadcasting terrestrial), a Japanese digital television broadcasting standard, was used in the evaluation assuming this as a primary system in WRAN (wireless regional area network) applications like IEEE 802.22.

DOI： 10.1587/transcom.E95.B.950

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

In this paper, the shadowing correlations among the multiple links between a coordinate node and sensor nodes in wireless BAN systems were investigated by measurements under everyday-life scenarios. We have developed a body-worn RSSI (receive signal strength indicator) logging system with off-the-shelf ZigBee sensor devices at 2.4 GHz for long time continuous and synchronized measurement among sensor nodes. The cross correlation coefficients calculated within a short time window were statistically characterized. The shadowing correlation will become useful information to develop and evaluate a multi-hop relay and a cooperative transmission scheme for increasing the reliability and power efficiency. © 2012 IEEE.

DOI： 10.1109/EuCAP.2012.6206638

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掲載種別：研究論文（国際会議プロシーディングス）  

The recent explosion of mobile Internet usage results in the need for higher data rate in future mobile communication systems. One of the key technologies to satisfy this requirement is the multilink transmission technique which utilizes the cooperative signal processing among spatially distributed multiple users and/or base stations, thus it is considered as more robust in ensuring the degree of freedom in spatial domain over the conventional single-link multiple-input-multiple-output (MIMO) systems [1]. However for the proper design and development of multi-link transmission systems, the level of inter-link channel correlation needs to be accurately modeled. Moreover since each user terminal and base station will also be equipped with multiple antennas, characterization of directional property at transmitter (Tx) and receiver (Rx) is also important for the design of array antennas. Previously, a lot of field measurement results reported focused on the characterization of multi-link propagation channel as summarized in [2]. However in the earlier works, channel stationarity is often assumed due to the limitations of channel sounder capabilities. Recently in [3], geometry-based multi-link channel modeling approach is proposed based on the measurement by dual-link MIMO channel sounder [4], and the propagation mechanisms which cause the correlation among two links are reported. Nevertheless, the existing results are still limited to specific frequency bands (below 2 GHz or 5 GHz) and environments, thus further evaluation based on the multi-link measurements is desired. © 2012 IEICE.

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掲載種別：研究論文（国際会議プロシーディングス）  

Multiple-input multiple-output (MIMO) systems have attracted lots of attentions, for their potential for high gain in channel capacity. For evaluating the performance of MIMO systems in more practical situations, more accurate channel models are necessary; and channel measurement is necessary to estimate the parameters of the channel models [1] [2]. In [2], we developed a fully parallel wideband MIMO channel sounding system at 11GHz with 400MHz bandwidth, which utilized software defined radio (SDR) architecture and is considered more suitable for real-time evaluation of link-level performance and channel properties, comparing with switching-based time division multiplexing (TDM) sounder, that has been commonly used [3]. However, one of the drawbacks of the fully parallel MIMO channel sounder system is that it needs complex procedures of baseband circuit adjustment, radio frequency (RF) circuit compensation, and back-to-back (B2B) calibration measurement, comparing with switching-based system; and the complexity increases with the numbers of transmit (Tx) and receive (Rx) channels. Since currently, the sounder system developed in[2] has been extended into 24 × 24 MIMO sounder, it becomes a very serious problem that it will take very long time to carry out the B2B calibration measurement for all possible MIMO connections. In this paper, automatic system calibration schemes are introduced and a simplified B2B calibration method is also proposed to shorten the measurement time. © 2012 IEICE.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Computer Society  

This paper proposed the skeleton model to generate human body models for predicting dynamic BAN channels by considering the simplified body geometry in analytical study. The numerical human body model was exported into skeleton in bvh (bio-vision hierarchy) file format. The cylinder body model is constructed by shaping the necessary bones of skeleton by cylinder. The feasibility of model is assessed by FDTD simulation. The results show reasonable agreement between channels calculated from the complex and simplified body models. By using skeleton, the motion data can be transferred into a small size file without losing necessary information for channel prediction. © 2012 IEEE.

DOI： 10.1109/EuCAP.2012.6206616

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

In this paper, we performed six human movement simulation by a commercial software (Poser7). We performed FDTD simulations for body area network propagation with one transmitter and six receivers. Received amplitudes were calculated for every time frame of 1/30 s interval. We also demonstrated a polarization diversity effectiveness for dynamic wearable body area network propagation.

DOI： 10.1587/transcom.E94.B.2496

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Post-disaster situation requires quick and effective rescue efforts by the first responders. Generally the rescue teams use wireless radios for intra-agency communications. Lack of collaboration among different rescue agencies may create interference among the emergency radios. Identification of some physical parameters of these active radios is necessary for collaboration. Carrier frequency and bandwidth can be estimated by spectrum sensing, whereas modulation classification requires further signal processing and classification operations. Processing speed and performance of the classification system can be controlled by appropriate selection of signal parameters, signal processing techniques and the classification algorithms. A wireless disaster area emergency network (W-DAEN) can be installed in the disaster area to detect and capture data (time samples) of the occupied frequencies. This study consists of some simulation results of a machine learning based cooperative automatic modulation classification technique by using six unique features. The classification performance and processing time of the proposed algorithm is quite satisfactory for real-time classification system. © 2011 ICST.

DOI： 10.4108/icst.crowncom.2011.245915

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

In this report, we performed six human movement simulation by a commercial software (Poser7). We performed FDTD simulations for body area network propagation with one transmitter and six receivers. Received amplitudes were calculated for every time frame of 1/30 s interval. We also demonstrated a polarization diversity effectiveness for dynamic wearable body area network propagation. © 2011 IEEE.

DOI： 10.1109/ISMICT.2011.5759798

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

This paper reports the development of MIMO channel sounder operating at 11 GHz with 400 MHz bandwidth. The sounder utilizes the software radio architecture to measure the full MIMO channels simultaneously, since the same hardware can be also used to test the real-time data transmission. © 2011 IEEE.

DOI： 10.1109/URSIGASS.2011.6050855

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

On-body communication channels are gaining increasing interests as more and more wireless devices are wearable in the fields of medicine, military, and personal communications. This paper presents an experimental investigation of the dynamic features of time-varying on-body channels with continuous movements of human body. Channel response at 10 antenna positions in two dynamic scenarios, walking and standing up and sitting down, have been measured in the anechoic chamber. Based on the statistical analyses of fading duration, a five-state Fritchman model that considers channel dwelling time at a given quality is proposed. Parameters of the Fritchman model are estimated from the measured data. The characteristics of simulated burst channels are in good agreement with the measurements. ©2010 IEEE.

DOI： 10.1109/ICC.2010.5502806

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

On-body communication channels are gaining increasing interests as more and more wireless devices are wearable in the fields of medicine, military, and personal communications. This paper presents an experimental investigation of the dynamic features of time-varying on-body channels with continuous movements of human body. Channel response at 10 antenna positions in two dynamic scenarios, walking and standing up and sitting down, have been measured in the anechoic chamber. Based on the statistical analyses of fading duration, a five-state Fritchman model that considers channel dwelling time at a given quality is proposed. Parameters of the Fritchman model are estimated from the measured data. The characteristics of simulated burst channels are in good agreement with the measurements.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In this paper, a centralized polling-based medium access (MAC) scheme, namely, the IEEE 802.11e hybrid coordinator function (HCF) controlled channel access (HCCA), is considered as an alternative to the current MAC protocol used in IEEE 802.11p for Wireless Access in Vehicular Environment (WAVE). At first, the limitations of the current enhanced distributed channel access (EDCA) are examined, and then a simple analytical performance evaluation of HCCA is provided. The results demonstrate that the HCCA scheme can be an alternative option to EDCA and could serve as an efficient channel access mechanism for vehicular communications.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper reports a study on the influence of the phase noise on a frequency division multiplexing (FDM) channel sounding. The channel sounder is designed for the analysis of the propagation channel at 11.0 GHz with a band-width of 400 MHz. It is expected that phase noise in such a high frequency and wide band-width affect the performance of the propagation channel analysis. The simulation results however suggest that the estimated parameters of the propagation channel are not significantly affected by the phase noise.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Big natural or manmade disasters damage infrastructure and cause severe effect on civilizations. Existing telecommunication infrastructure goes down as well as power, water etc. Quick and effective rescue operation requires a collaborative communication infrastructure for the rescue teams. Emergency spectrum usage of the rescue teams is one of the major issues in such scenario. Different teams interfere with each other for lack of collaboration and infrastructure limitations. This study designed and developed a cognitive wireless sensor network that collects and forms a database of the active emitters on the disaster scene. This paper focuses especially on a distributed spectrum sensing scheme for the emergency radios. ©2010 IEEE.

DOI： 10.1109/ISCIT.2010.5665132

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This paper presents a framework of multimode fully digital receiver implementation using direct RF-to-digital conversion. In this architecture the entire band including multiple RF systems is directly converted to digital by a wideband high speed ADC, and the RF systems can be easily switched by only digital signal processing with the minimum analog RF components. The digital RF front-end consists of parallel processing blocks for parallel data streams considering practical ADC's configuration. The RF signals are converted into baseband through digital IF stage and the data rates are made down by two steps of decimation. In this paper, a principle investigation into a dualmode system implementation is presented for simplicity. The circuit resource and the robustness to the spurs (spurious outputs) of an NCO (numerically controlled oscillator) in the proposed design will be presented. The proposed architecture was implemented with an FPGA on the developed prototype system and the operations were also verified.

DOI： 10.1587/transfun.E92.A.1056

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

As a growing interest in the cognitive radio technology has been taken based on the idea of opportunistic spectrum use, the spectrum sensing technique for dynamic channel environment is more and more important to ensure that cognitive radios would not interfere with primary systems while it achieves reasonable throughput opportunistically. Architecture based on filter bank allows to sense multi-channels simultaneously with low spectrum leakage from adjacent channels thanks to efficient implementation of bandpass filters. Therefore it is now attracting much interest. In this paper, we propose a framework of multi-channel sensing architecture based on polyphase DFT filter bank followed by energy detector with minimum complexity. The sensing performance is evaluated by numerical simulation as well as theoretical analysis comparing with the conventional periodogram spectral estimator and time domain sequential sensing.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

This letter presents the characterization of an on-body propagation channel with a specific activity of a body on the basis of the measurement results of a male subject in a radio anechoic chamber. In order to capture the dynamic behavior of the channel, a commercial real-time channel sounding system for the 4.5-GHz narrowband was used. The measurement scenarios included two repetitive actions of walking on the spot and standing up and sitting down at 10 different receive antenna locations where the fading caused by the action was observed and statistically modeled.

DOI： 10.1109/LAWP.2009.2036570

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

On-body communication channels are of increasing interest as more and more wireless devices are wearable in medical, military, and personal communications. This letter presents an experimental investigation into the dynamic on-body channel with body movements. Based on statistical analyses of level crossing rate and fading duration, a three-state Fritchman model that considers both channel dwelling time and channel quality is proposed to describe the burst characteristics of on-body fading. The dynamic on-body channels are classified into unstable error-free state, constant error-free state, and error state. Parameters for the Fritchman model are estimated from the measured data.

DOI： 10.1109/LAWP.2009.2036749

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER INTERNATIONAL PUBLISHING AG  

In the early deployment of electric toll collecting (ETC) system, multipath interference has caused the malfunction of the system. Therefore, radio absorbers are installed in the toll gate to suppress the scattering effects. This paper presents a novel radio propagation measurement system using the beamforming with 8-elmenet antenna array to examine the power intensity distribution of the ETC gate in real time without closing the toll gates that are already open for traffic. In addition, an identification method of the individual scattering objects with 3D visualization by using virtual reality modeling language will be proposed and the validity is also demonstrated by applying to the measurement data. Copyright (C) 2009 Minseok Kim et al.

DOI： 10.1155/2009/131576

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

The input impedance of an antenna fluctuates because of various usage conditions, which causes a mismatch between an internal circuit and an antenna. An automatic matching system solves this problem. then this paper presents a reconfigurable impedance tuner that has a set of fixed capacitors controlled by switching p-i-n diodes. A fast control algorithm for selecting the appropriate conditions of an impedance tuner is proposed and mounted on FPGA to demonstrate the performance.

DOI： 10.1093/ietele/e91-c.8.1348

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

At present, when using space-time processing techniques with multiple antennas for mobile radio communication, real-time weight adaptation is necessary. Due to the progress of integrated circuit technology, dedicated processor implementation with ASIC or FPGA can be employed to implement various wireless applications. This paper presents a resource and performance evaluation of the QRD-RLS systolic array processor based on fixed-point CORDIC algorithm with FPGA. In this paper, to save hardware resources, we propose the shared architecture of a complex CORDIC processor. The required precision of internal calculation, the circuit area for the number of antenna elements and wordlength, and the processing speed will be evaluated. The resource estimation provides a possible processor configuration with a current FPGA on the market. Computer simulations assuming a fading channel will show a fast convergence property with a finite number of training symbols. The proposed architecture has also been implemented and its operation was verified by beam-forming evaluation through a radio propagation experiment.

DOI： 10.1093/ietcom/e91-b.4.1068

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This letter evaluates a transmitter architecture using harmonic images in D/A conversion for generating RF signals. In generating harmonic images, the problems such as intermodulation distortion of DAC were investigated. We developed an evaluation system with two bandpass filter and a buffer amplifier. It was experimentally found that the RF signal up to around 400 MHz can be generated by a commonly used 14-bit DAC at the sampling rates of around 40 MHz with EVM less than 6.6%. This letter also presents a more feasible transmitter example having an IF stage with harmonic image extraction scheme and a typical RF upconversion stage.

DOI： 10.1093/ietcom/e91-b.4.1215

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

This paper proposes a new design of a dualmode operation antenna. We introduced loop-shaped inverted-F wire antenna using a parasitic element within a feeding element for additional resonance mode that has small and low profiled structure. This paper discusses theoretical dual resonance operation and investigates the characteristics along some dimensional parameters by numerical analyses. The measurement results with the proposed structure will be also presented.

DOI： 10.1109/LAWP.2008.915805

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人電子情報通信学会  

本論文では, MMSE (Minimum Mean Square Error)アダプティブアレーアンテナの高速処理を目的として, そのアルゴリズムのFPGA (Field Programmable Gate Array)への実装法について検討を行っている.並列処理が可能であるFPGAを用いることで処理速度の向上を図ることが考えられるが, FPGAは固定小数点での演算が適しているため, 固定ワード長でのアルゴリズム処理の精度について検討する必要がある.本論文では, 収束が速く演算精度が良いとされるRLSアルゴリズムをFPGAに実装して送受信系システムの構築により実験的に検討することを目的とし, 入力情報及び内部変数の固定ワード長の決定やシフト演算による除算の検討を行い, 固定小数点演算を用いてRLSアルゴリズムのシミュレーションを行ってその演算精度を確認した.また, 実際にRLSアルゴリズムをFPGAに実装し, 同期処理部を含めた送受信システムを構築して伝搬実験を行い, BER特性よりその性能を評価した.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Undersampling (or bandpass sampling) phase modulated signals directly at high frequency band, the harmful effects of the aperture jitter characteristics of ADCs (Analog-to-Digital converters) and sampling clock instability of the system can not be ignored. In communication systems the sampling jitter brings additional phase noise to the constellation pattern besides thermal noise, thus the BER (bit error rate) performance will be degraded. This paper examines the relationship between the input frequency to ADC and the sampling jitter in digital IF (Intermediate Frequency) downconversion receivers with undersampling scheme. This paper presents the measurement results with a real hardware prototype system as well as the computer simulation results with a theoretically modeled IF sampling receiver. We evaluated EVM (Error Vector Magnitude) in various clock jitter configurations with commonly used and reasonable cost ADCs of which sampling rates was 40 MHz. According to the results, the IF input frequencies of QPSK (16 QAM) signals were limited below around 290 (210) MHz for wireless LAN standard, and 730 (450) MHz for W-CDMA standard, respectively, in our best configuration.

DOI： 10.1093/ietisy/e88-d.7.1430

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記述言語：英語   掲載種別：学位論文（その他）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electronics, Information and Communication, Engineers, IEICE  

Undersampling (or bandpass sampling) phase modulated signals directly at high frequency band, the harmful effects of the aperture jitter characteristics of ADCs (Analog-to-Digital converters) and sampling clock instability of the system can not be ignored. In communication systems the sampling jitter brings additional phase noise to the constellation pattern besides thermal noise, thus the BER (bit error rate) performance will be degraded. This paper examines the relationship between the input frequency to ADC and the sampling jitter in digital IF (Intermediate Frequency) downconversion receivers with undersampling scheme. This paper presents the measurement results with a real hardware prototype system as well as the computer simulation results with a theoretically modeled IF sampling receiver. We evaluated EVM (Error Vector Magnitude) in various clock jitter configurations with commonly used and reasonable cost ADCs of which sampling rates was 40 MHz. According to the results, the IF input frequencies of QPSK (16 QAM) signals were limited below around 290 (210) MHz for wireless LAN standard, and 730 (450) MHz for W-CDMA standard, respectively, in our best configuration. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1093/ietisy/e88-d.7.1430

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

DOA (Direction Of Arrival) estimation is a useful technique in various positioning applications including the DOA-based adaptive array antenna system. This paper presents a practical implementation of FPGA (Field Programmable Gate Array) based fast DOA estimator for wireless cellular basestation. This system incorporates spectral unitary MUSIC (MUltiple SIgnal Classification) algorithm, which is one of the representative super resolution DOA estimation techniques. This paper proposes a way of digital signal processor design suitable for FPGA and its real hardware implementation. In this system, all digital signal processing procedures are computed by the only fixed-point operation with finite word-length for fast processing and low power consumption. The performance will be assessed by hardware level simulations and experiments in a radio anechoic chamber.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Electrical and Electronics Engineers Inc.  

In recent and future wireless cellular communications, Co-Channel Interference (CCI) is very critical problem. At basestation, adaptive array antenna technology exploiting spatial domain filtering with antenna array and digital signal processing can combat the CCI, thus the system capacity can be increased. Most algorithms for adaptive array antenna system have been studied. Most algorithms usually need directions of arrival (DOAs) of desired and interferer signals in advance. The DOA-based adaptive array antenna systems make use of the estimated DOAs in a beamformer in order to separate the desired signal from interferers spatially. But, of course, there are other types of algorithms that exploit temporal reference and not need the DOA information. The performance of DOA,-based beamforming is superior to that of other types of algorithms for small angular spread, while it has time-consuming tasks due to its large amount of computational burden [1].

DOI： 10.1109/WCT.2003.1321565

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Computing the Eigen Value Decomposition (EVD) of a symmetric matrix is a frequently encountered problem in adaptive (or smart or software) antenna signal processing, for example, super resolution DOA (Direction Of Arrival) estimation algorithms such as MUSIC (MUltiple SIgnal Classification) and ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique). In this paper the hardware architecture of the fast EVD processor of symmetric correlation matrices for the application of an adaptive antenna technology such as DOA estimation is proposed and the basic idea is also presented. Cyclic Jacobi method is well known for the simplest algorithm and easily implemented but its convergence time is slower than other factorization algorithm like QR-method. But if considering the fast parallel computation of the EVD with a hardware architecture like ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), the Jacobi method can be a appropriate solution, since it offers a quite higher degree of parallelism and easier implementation than other factorization algorithms. This paper computes the EVD using a Jacobi-type method, where the vector rotations and the angles of the rotations are obtained by CORDIC (COordinate Rotation DIgital Computer). The hardware architecture suitable for ASIC or FPGA with fixed-point arithmetic is presented. Because it consists of only shift and add operations, this hardware friendly feature provides easy and efficient implementation. In this paper, the computational load, the estimate of circuit scale and expected performance are discussed and the validation of fixed-point arithmetic for the practical application to MUSIC DOA estimation is examined.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Computing the Eigen Value Decomposition (EVD) of a symmetric matrix is a frequently encountered problem in adaptive (or smart or software) antenna signal processing, for example, super resolution DOA (Direction Of Arrival) estimation algorithms such as MUSIC (MUltiple SIgnal Classification) and ESPRIT(Estimation of Signal Parameters via Rotational Invariance Technique). In this paper the hardware architecture of the fast EVD processor of a symmetric correlation matrix for the application of an adaptive antenna technology such as DOA estimation is proposed and the basic idea is also presented. ©2002 IEEE.

DOI： 10.1109/PIMRC.2002.1046673

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

将来高速な無線通信の需要が更に高まると予想されており、それを実現するために空き周波数が比較的多く、広帯域確保可能なミリ波帯が注目を集めている。次世代ヘテロジニアスネットワークにおけるピコセルの周波数帯域として、連続的に5GHz以上の帯域が確保できる60GHz帯は有力な候補と考えられる。60GHzにおいては、自由空間損失、及び大気吸収損失が大きいため、高利得な指向性アンテナやアレーアンテナが必要となる。さらに、MIMOビームフォーミングやビームステアリングなどの技術を用いる際、方向性を含む電波伝搬路特性を様々な環境で調べることが重要である。本研究では、放射方向、及び到来方向の角度電力スペクトルが測定可能かつ低コストなミリ波帯チャネルサウンダを提案し、一般的な屋内環境における実験の解析結果を示す。

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

This paper presents a low-cost flexible channel sounder with the maximum bandwidth of 12.5MHz operating at various frequency bands within 400 - 4400 MHz developed by using GNU radio/USRP. This paper describes an improved work based on its previous channel sounding system and especially focuses on the techniques of timing synchronization and phase alignment which were hard to achieve in its previous work. Finally, The effect of improvement of previous work was demonstrated and validated by a DUT test.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Elucidation of the space-time radio wave propagation characteristics is always an important fundamental task to develop new wireless transmission systems. For this purpose, we specifically developed a scalable full Multiple-Input Multiple-Output (MIMO) channel sounder to measure the radio channel at 11 GHz with bandwidth of 400 MHz which is a challenging frequency for future high bit-rate mobile communications. The measurement campaign in various indoor environment was conducted at Tokyo Institute of Technology. Individual paths are extracted from the measurement with the Space Alternating Generalized Expectation Maximization (SAGE) algorithm. For cluster based analysis, we used K-means algorithm for automatic clustering of the detected paths and the statistical characteristics of cross-, co-polarization ratio, delay spread and direction spread were investigated based on clustering result.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

10GHz以上の高周波数帯は広帯域が確保できるため更なる高速移動通信を実現するために注目されている.本報告では,石垣島で実施した11GHz帯市街地マイクロセルラ環境における電波伝搬測定の解析結果を報告する.伝搬測定では,400MHzの帯域幅を持つ広帯域24×24MIMOチャネルサウンダと直交二偏波12素子円形アレーアンテナを用いており,基地局アンテナがマンションの3階(約9m)に設置され,半径約200mの住居エリアをアンテナ高3mの移動局が走行しながら伝達関数を測定した.データ解析はビーム形成による角度遅延電力分布とSAGE法によるマルチパスパラメタを用いた.本稿では,まず,見通し内・交差点見通し外における伝搬損失の距離特性と偏波特性,RMS遅延広がりについて報告する.それから,解析対象を半径60mのエリアに絞り,移動局位置の変化による角度遅延電力分布とマルチパスパラメタの変化を解析し支配的な伝搬メカニズムを考察する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

10GHz以上の高周波数帯は広帯域が確保できるため更なる高速移動通信を実現するために注目されている.本報告では,石垣島で実施した11GHz帯市街地マイクロセルラ環境における電波伝搬測定の解析結果を報告する.伝搬測定では,400MHzの帯域幅を持つ広帯域24×24MIMOチャネルサウンダと直交二偏波12素子円形アレーアンテナを用いており,基地局アンテナがマンションの3階(約9m)に設置され,半径約200mの住居エリアをアンテナ高3mの移動局が走行しながら伝達関数を測定した.データ解析はビーム形成による角度遅延電力分布とSAGE法によるマルチパスパラメタを用いた.本稿では,まず,見通し内・交差点見通し外における伝搬損失の距離特性と偏波特性,RMS遅延広がりについて報告する.それから,解析対象を半径60mのエリアに絞り,移動局位置の変化による角度遅延電力分布とマルチパスパラメタの変化を解析し支配的な伝搬メカニズムを考察する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

10GHz以上の高周波数帯は広帯域が確保できるため更なる高速移動通信を実現するために注目されている.本報告では,石垣島で実施した11GHz帯市街地セルラ環境における電波伝搬測定の解析結果を報告する.伝搬測定は基地局アンテナの高さの異なるマクロ,マイクロ,ストリートセルの各環境において,400MHzの帯域幅を持つ広帯域24×24MIMOチャネルサウンダと二偏波12素子円形アレーを用いて実施された.本報告では,各環境における伝搬損失を評価し,見通し外の環境では約20dB程度の大きいシャドウイング損失を観測した.さらに,アウテージ評価により,SN比の30dBを満たすセル半径が100m未満に限定されることを確認した.また,遅延プロファイルと角度遅延電力スペクトルを用いて,伝搬路の時空間特性について考察した結果,空間的に広く分布する多数のマルチパスが観測されたが,平均RMS遅延広がりが15ns未満と比較的に小さいことを確認した.さらに,RMS遅延広がりが伝搬損失と比例することを確認した.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Antenna de-embedding is to extract antennas from both ends of a MIMO system and to study the propagation channel only. Antenna-Channel Recombination is to recombine the de-embedded channel with other antennas at both ends. Through antenna de-embedding and antenna-channel recombination, the performances of different antennas in certain propagation environment can be evaluated. A MIMO channel can be described in either plane wave domain or spherical wave domain. Plane wave channel model is difficult for antenna-channel separation, since diffuse scattering requires infinite resolution of plane waves but practically only best fitted discrete paths are feasible. Alternatively, spherical wave channel model is possible for antenna-channel separation, because physically any radiated field can be expanded into a weighted sum of spherical harmonics with finite number of modes, including the field corresponding to diffuse scattering. This paper will study the feasibility of antenna de-embedding and antenna-channel recombination in spherical wave domain. Since spherical wave channel model is sensitive to array configurations and the number of modes, the criteria of appropriate array configurations and appropriate number of modes for antenna de-embedding and antenna-channel recombination will be discussed accordingly.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Antenna de-embedding is to extract antennas from both ends of a MIMO system and to study the propagation channel only. Antenna-Channel Recombination is to recombine the de-embedded channel with other antennas at both ends. Through antenna de-embedding and antenna-channel recombination, the performances of different antennas in certain propagation environment can be evaluated. A MIMO channel can be described in either plane wave domain or spherical wave domain. Plane wave channel model is difficult for antenna-channel separation, since diffuse scattering requires infinite resolution of plane waves but practically only best fitted discrete paths are feasible. Alternatively, spherical wave channel model is possible for antenna-channel separation, because physically any radiated field can be expanded into a weighted sum of spherical harmonics with finite number of modes, including the field corresponding to diffuse scattering. This paper will study the feasibility of antenna de-embedding and antenna-channel recombination in spherical wave domain. Since spherical wave channel model is sensitive to array configurations and the number of modes, the criteria of appropriate array configurations and appropriate number of modes for antenna de-embedding and antenna-channel recombination will be discussed accordingly.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

無線バイタルセンサネットワークにおいてデータを継続的に収集するためには,無線伝送における信頼性の向上が必要不可欠である.広帯域無線伝送でおいては,マルチパス遅延波を合成するRAKEダイバーシティや,複数アンテナを用いたダイバーシティ技術を用いることにより,人体遮蔽による受信電力レベル低下が軽減可能であり,ロバストな無線伝送リンクの構築に有効である.しかしながらこれらのシステムは,伝搬環境におけるマルチパス伝搬路の状況によりその性能が決定される.本研究では,消費電力や取り付け自由度の高いUWB BAN(ultra wideband body area network)コーディネータに着目し,ベルト状に複数アンテナを取り付けた場合の伝搬実験を行った.そして,信頼性を向上させる手法として,RAKEダイバーシティおよびアンテナダイバーシティの導入を想定し,それぞれの手法における性能改善を評価した.特に,室内における被験者の立ち位置の改善効果への影響について検討した.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Body Area Network(BAN)の規格であるIEEE 802.15.6においては,アウテージ性能を改善するために隣接ノードによる中継が推奨されている.本稿では,隣接ノードが協調中継ノードとして動作し,宛先であるコーディネータノードがダイバーシチ合成を行う場合のアウテージ性能を評価する.アウテージ性能評価には,チャネル測定結果から導出したチャネルモデルを用いた.チャネル測定は,実利用が想定される生体センサ位置に測定ノードを配置し,全ノード間のマルチリンクチャネル測定を3種類の動作シナリオに対して行ったものである.協調中継有り・無しの場合について10%のアウテージ確率を与えるSNRを計算し,それらの差で定義されるパフォーマンスゲインを評価した.その結果,パフォーマンスゲインの最大値が16dBであることを明らかにした.また,コーディネータ位置を変えた場合にも評価を行い,コーディネータがどのような位置にあっても,5.58dB以上のパフォーマンスゲインが得られることを明らかにした.さらに,アウテージ性能の観点から最適なコーディネータ位置の検討も行った.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本研究では、人体歩行時のWBANにおいて安定的に通信を行うことができる体表上のアンテナの配置を明らかにすることを目的とした。まず、2.4GHzでの電波伝搬測定に必要なWBAN用アンテナの設計および試作を行った。次に、試作したアンテナを歩行の人体動作時におけるWBAN電波伝搬測定に基づき良好な通信状況となるアンテナ配置方向の検討を行った。被験者2人について室内環境で臍を送信点、胸、頭、右上腕、右手首、右足首を受信点として直立及び歩行動作時の1対1での受信レベルの時間変化を測定した。この平均値について被験者及び受信アンテナの位置ごとに二元配置分散分析を行った結果、送受信のアンテナ配置方向が受信レベル変化の要因となっていることが定量的に明らかになった。また、直立及び歩行動作時に1対1通信を行う場合には被験者に共通して、臍にあるアンテナ配置方向を変えることが受信レベルの改善に有効、1対多の場合には最適な配置方向は被験者ごとに異なるという結果が得られた。本研究で得られた知見は今後高信頼性のWBANシステム設計を行う上で有効と考えられる。

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

This paper presents a low-cost flexible MIMO channel sounder with the maximum bandwidth of 25MHz operating at various frequency bands between 400 MHz and 4400 MHz developed by using GNU radio/USRP that employs a simple time division multiplexing (TDM) scheme. This paper describes the principle of the channel sounding technique, data processing, and presents the hardware setup as a MIMO channel sounder in detail. By computer simulation, this paper also clarifies the influence of the most critical transceiver imperfections such as phase noise (PN) and I/Q imbalance (IQI) on channel estimation accuracy. The operation is demonstrated and validated by a simple DUT test, and MISO test by fading simulator.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では,マルチパス環境における指向性を有する円形アレーを用いたパスゲインの計算法を提案する.双方向チャネル測定には,実装上の問題から指向性を有する円形アレー使用することが一般的であり,交差偏波識別度(XPD)が10数dBと制限されているため,偏波成分ことの正確なパスゲインを求めることが困難である.本報告では,まず,ビームフォーミングによる角度電力スペクトルからパスゲインを求める方法について説明し,その推定誤差を改善できる固有ビーム形成法を提案する.本提案手法は,アレー応答ベクトルを固有空間とサンプルアレーベクトルに分離し,固有ビーム形成により無指向性のサンプルアレーベクトルから生成されるチャネル行列に変換し,行列のノルムからパスゲインを推定する.さらに,主偏波と交差偏波を部分空間で分離し,パスゲインの交差偏波成分をより正確に計算できる.本手法の有効性は,開発した円形アレーのパタンデータを用いて計算機解析により検証された.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本研究では,11GHz帯マイクロセル環境においてMIMOチャネルサウンダによる電波特性測定を行うとともに,同環境を模したレイトレースシミュレーションを行った.両者の角度遅延電力スペクトルの比較と伝搬パスの可視化により電波伝搬における散乱メカニズムの解釈を行い,レイトレースシミュレーションでは考慮に入れない非正規散乱の受信電力における影響を確認した.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

A field measurement was conducted in Ishigaki city with the developed MIMO (multi-input multi-output) channel sounder. One of the main streets of Ishigaki city is measured for resolve the propagation environment of the macrocell of mobile communication at 11 GHz. The employed antenna arrays are circular arrays at both the transmitter (Tx) and receiver (Rx); or linear arrays and 12 QAM arrays at the Rx and Tx sides, respectively. The circular arrays are designed for estimating the angle of arrival (AOA) and angle of departure (AOD) of the multipaths, and the linear and 12 QAM arrays are employed for measuring the MIMO channels. In this paper, we show the analysis results of the path gain that calculated from the channel transfer functions measured with the circular arrays and compare them with that measured by the linear and 12 QAM arrays. The eigenvalues and capacity results of the channels also showed for evaluation of the environment.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

A field measurement was conducted in Ishigaki Island with the developed MIMO (multi-input multi-output) channel sounder. One of the main streets of Ishigaki city is measured for resolve the propagation environment of the microcell of mobile communication at 11 GHz. The employed antenna arrays at the transmitter (Tx) and receiver (Rx) are circular arrays, that designed for estimating the angle of arrival (AOA) and angle of departure (AOD) of the multipaths. In this paper, we show the analysis results of the path gain and delay spread for different polarization with the channel transfer functions that measured with the circular arrays.

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）   出版者・発行元：電子情報通信学会  

安価で誰でも手軽に構築できる無線システムとして,GNU Radioオープンソースソフトウェア無線プラットホームが注目されている.その評価用ハードウェアとして提供されるUSRPは,RF信号を周波数変換しサンプリングして,複素ベースバンド信号に変換する.その後の全ての処理はUSB2.0あるいはギガビットイーサーネットを経由して接続されたPC上のソフトウェアによりリアルタイムで行われる.本稿では,GNU Radioの基本概念,ソフトウェア・ハードウェアの構成,ハードウェアの特徴と制約を紹介し,最後にコグニティブ無線技術の試作例を紹介する.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

ボディエリアネットワーク(BAN)とは体内,体表,人体周辺での通信ネットワークのことで,将来的に医療分野を始めとして,エンターテイメント,スポーツ等の様々な分野への応用が期待されている.BANにおいては,人体動作による遮断効果が生じ伝搬特性が劣化するため,動的なチャネル特性の把握が重要である.従来のベクトルネットワークアナライザによる広帯域チャネル測定法では,周波数掃引に時間を要し動的チャネルを正しく測定することが困難である.また,複数チャネル間の相関関係を解明するためにはマルチチャネル測定が必要となる.このような背景から,本研究ではマルチチャネルオシロスコープを用いた時間領域チャネル測定装置を構築し,その妥当性に関する検証を行った.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本稿ではBAN(Body Area Network)における電波伝搬特性モデリングに向けて,FDTD法を用いた人体近傍でのパスロスのシミュレーション結果を示す.始めに,FDTD法によるパスロスのシミュレーションの有効性を検証するために,人体と同じスケール・媒質定数を有する損失誘電体球による散乱問題の厳密解との比較を行った.そのうえで,on-body間のノードの通信を想定して歩行動作によるパスロス変動のシミュレーションを行った.シミュレーション結果から,送信アンテナ3方向および受信アンテナ3方向の全ての偏波の組み合わせについて,偏波間の比較を行った.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

将来の移動通信システムにおける更なる高速大容量化を実現するための基礎検討として,高周波帯の活用及びMIMOマルチリンク協調技術の導入を前提とした伝送方式の研究・装置化が進められている.本報告では,このような無線通信システムの実現可能性を明らかにするため,11GHz帯における屋内MIMOマルチリンク伝搬測定を実施し,取得した3リンクの4×4MIMO伝搬行列から,マルチリンク協調技術の設計において重要とな,るリンク間の相関について検討を行った.測定に使用したシステムは,すでに開発した4×4MIMOチャネルサウンダをマルチリンク測定用に拡張したものであり,11GHz帯MIMO伝搬路における複数リンク間の相関だけでなく,受信側における遅延角度情報から伝搬メカニズムを推定することも可能である.測定は屋内ホール環境で行い,柱により遮蔽されるポイントを除き常に見通しが存在する構成とした.また,環境内における移動物体の影響が無視できるよう配慮して実験を行った.各リンクのMIMO伝搬行列の固有値変動と到来方向測定から推定された伝搬メカニズムを合わせて評価した結果,送信アンテナに対する見通しの有無によってリンク間の相関が特性づけられることが明らかとなった.今後は,送受それぞれ3ユニットに分割可能な24×24MIMOシステムを使用して屋内・屋外において伝搬測定を行い,様々な環境における高周波帯MIMO伝搬路の特性を明らかにしていく予定である.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では,広帯域直交変調器における周波数選択性I/Qインバランス補償法を提案する.本手法は,直交変調器のRF出力の電力スペクトルをスペクトルアナライザで観測し,イメージ抑圧比を最大にすることで,回路パラメタを推定する実験的なアルゴリズムを開発した.I/Qインバランスの周波数選択性は,IとQチャネルの低域通過フィルタやDA変換器などの総合的な周波数特性のばらつきが原因で生じるが,本手法では,信号帯域を複数のサブバンドに分割しそれぞれの回路パラメタを推定する.また,推定されたパラメタを用いて周波数領域プリディストーションを行い,RF出力信号に現れるイメージ干渉とDCオフセット成分を低減する.本報告で開発した手法の検証のため,評価システムを構築し,400MHzの広帯域にわたって,十分なイメージ抑圧の達成できることを確認した.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

高速伝送レートを実現する無線通信に対する要求が一層高まっており,高速伝送レートを実現するためには新たな周波数の開拓が必要である.なお,フェムトセルのように小さなエリアにおける利用形態の増加が予想され,個別環境における電波伝搬特性を解明することが重要とされている.本研究では,個別環境の電波伝搬チャネルを効率的に測定するために,広帯域双角度チャネル特性およびマルチリンクMIMOチャネル特性の測定が柔軟に行える24×24MIMOチャネルサウンダを開発した.本報告では,スケーラブルなチャネル測定手法を紹介し,複数送受信ユニットを制御するハードウェア・ソフトウェアの仕様を説明する.さらに,動作検証として行った屋内伝搬実験における到来方向推定例を紹介する.

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記述言語：日本語   出版者・発行元：[信号処理学会]  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Many modulation schemes exhibit a peak along the cross-section of the spectral correlation density (SCD) at the carrier frequency, where the cyclic frequency of that peak represents the symbol rate of the received signal. In this paper, a symbol rate estimation technique for various modulated signals is proposed. Window functions are used to improve discrete Fourier transform (DFT) results, and a simple filter is used to amplify peaks across the cyclic frequency domain. The proposed technique can be used together with feature extraction to perform AMC. Simulation results show that the proposed technique can estimate the symbol rate and classify modulations with good performance at SNRs of 4dB and above.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では,TVホワイトスペースを利用したエリア放送型システムのための技術的条件(案)に準拠し,都内における利用可能チャネル数の試算例を紹介する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

著者らは,直交変調器のIQインバランスの狭帯域モデルから,スペクトラムアナライザを用いて入力信号における特定の周波数の振幅成分だけを取得し,IQインバランス補償を行う簡易補償法を提案した.本報告では,この手法により広帯域における補償法について検討し、4×4MIMO送信機での検証結果について報告する.本補償法は直交変調された信号スペクトルをフィードバックし,モデルパラメタの最適値を逐次推定する.実際の広帯域直交変調器に存在する周波数特性への対策として,帯域を複数に分けて補償を行うサブバンドを用いた補償法を提案し,その効果を確かめる.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Dept. of International Development Engineering, Tokyo Institute of Technology

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

将来の移動通信システムにおける更なる高速大容量化を実現するための基礎検討として,高周波帯の活用を前提とした伝送方式の研究・装置化が進められている.本報告では,上記の前提に基づいて既に開発した4×4 MIMOソフトウェア無線機を拡張した8×8システムについて報告するとともに,広帯域双角度チャネル特性およびマルチリンクMIMOチャネル特性の測定を念頭に置いたアレーアンテナ構成,及びチャネルサウンディング手法を提案する.ソフトウェア無線アーキテクチャを採用することにより,ビット誤り率やパケット誤り率などの伝送特性と伝搬路特性を実環境において同時に測定・評価できる.さらに,送信機・受信機をユニット単位で増設・分割することが可能であり,将来導入が予想されるマルチリンクMIMOシステムの実環境における評価にも適用できる利点がある.チャネルサウンダの性能としては,伝搬路の時間変動測定のために,1つのMIMOチャネル行列測定に要する時間が重要な指標となるが,提案するハードウェア構成及び多重化法を用いることにより一般的なスイッチング方式のチャネルサウンダと比較して,測定可能なドップラー変動を大きく拡張できる.提案手法の有効性を検証するため,開発した試作機を用いてチャネルサウンダとしての動作検証実験を行い,装置化したハードウェアおよびサウンディング手法の有効性を確認した.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Automatic modulation classification (AMC) is an important component for cognitive radio (CR) in order to identify unknown signals and is useful for CRs to fully grasp the condition of the radio environment. In this paper, signal cyclostationarity has been utilized for AMC. The spectral correlation density (SCD) is calculated, and the cyclic frequencies of the spectral peaks are collected as features. Taking hardware implementation into consideration, a decision tree is used as a classifier due to lower complexity. The targeted modulations in this paper are AM, BPSK, QPSK, 8PSK, π/2-DBPSK, π/4-DQPSK, OQPSK, MSK, GMSK, 2FSK and 4FSK signals. Simulation results show reasonable classification performance at SNRs of 6 dB and above.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Automatic modulation classification (AMC) is used in many military and civilian applications such as surveillance, spectrum monitoring, security, emitter identification, cognitive radio etc. Typically the receivers for the AMC is blind in nature i.e there is no pilot channel or known training sequence between the transmitters and receivers. This requires some non-data aided (NDA) signal processing in the receiver side. The detection algorithm becomes more complex in an environment where emitters use both analog and digital modulation schemes. AMC unit must estimate the carrier frequency, bandwidth, symbol rate etc. for accurate detection of the modulation types. In this demonstration, a feature based AMC algorithm will be introduced in the software defined radio (SDR) platform by using universal software peripheral radio (USRP), GNU radio and some open-source software.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では,広帯域双角度チャネル特性およびマルチリンクMIMOチャネル特性の測定を念頭に置いたチャネルサウンダをMIMOソフトウェア無線(SDR)アーキテクチャを用いて実現する方法を提案し,従来方式との比較によりその得失を議論する.SDRアーキテクチャを採用した提案方式では,ビット誤り率やパケット誤り率などの伝送特性と伝搬路特性の関係をリアルタイムに解析できる.さらに,送信機・受信機をユニット単位で増設・分割することが可能であり,将来導入が予想されるマルチリンクMIMOシステムの実環境における評価にも適用できる利点がある.提案手法の有効性を検証するため,4×4MIMO構成の試作機を用いてチャネルサウンダとしての動作検証実験を行い,提案するチャネルサウンディング手法の有効性を確認した.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

近年,安価で誰でも手軽に構築できる無線評価システムとして,GNU Radioオープンソース・ソフトウェア無線プラットフォームが注目を浴びている.その評価用ハードウェアとして開発されたUSRPで,周波数変換とサンプリングを行い複素ベースバンド信号に変換し,その後の全ての処理はUSB 2.0あるいはGigabit Ethernetで接続されたPC上のソフトウェアによりリアルタイムで行われる.ハードウェアに関わる下位層の処理はライブラリとしてオープンソースで提供されるため,物理層の専門知識をそれ程必要とせず,USRPの性能内であれば誰でも手軽に自分の試作機を構築することが可能である.本稿では,GNU Radioの基本概念,ソフトウェア・ハードウェアの構成,ハードウェアの制約などを紹介し,ソフトウェア無線とコグニティブ無線システムの試作と評価用にGNU Radioを導入した研究例を紹介する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Emergency rescue operations require quick and efficient setup of collapsed telecommunication infrastructure in the disaster area. In a scenario where international rescue teams come for help, an automatic network collaboration system is necessary to avoid the interferences. This work developed a prototype that can detect the presence of active emergency radios with some physical parameters and maintain a public database. The prototype can demonstrate some basic functions of the proposed system. Energy detector based cooperative spectrum sensing as well as a supervised learning based automatic modulation recognition system have been implemented by using USRP and GNU Radio.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

無線チャネルを測定・解析・モデル化する際に,通信機器の一部である送受信アンテナをチャネルから切り出し,アンテナに依存しない電波伝搬路モデルを構築するアプローチは双角度チャネルモデルと呼ばれている.本稿では,双角度チャネルモデルを球波動関数を用いて再構築することを目的とし,実際のアンテナ及び伝搬路特性に対して球波動関数による表現を試みる.さらに,球波動関数を用いて再構成した複素放射パタンを示し,また再構成のために必要とされるモード数を議論する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

近年,Opportunisticな周波数の二次利用により周波数の効率的な利用を図るコグニティブ無線技術が注目をされるなか,既存システムに干渉を与えないために既存システムのスペクトル利用状況を高い信頼性で判断するスペクトルセンシング技術が重要な課題となっている.本報告では,スペクトル検出の信頼性を高める手法としてOFDM信号の周期定常性を用いるCyclic Detectorについて解説するとともに,効率的な広帯域スペクトル検出手法としてポリフェーズDFTフィルタバンクを利用した複数チャネルセンシング機構について紹介する.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Scarcity of wireless channels leads the researchers to develop opportunistic spectrum usage systems. Spectrum sensing is the most important and complex job for the cognitive radios. Spectrum sensing may play a vital role to detect the presence of unknown emitters in a noisy and multi-path environment. In emergency situations (i.e. after earthquake) a number of rescue teams come to the field and setup their own radio communication systems. If the teams have no collaboration among themselves (which is most likely), they may interfere with each other by using same RF channels. One of the possible way to detect the presence of emitters is spectrum sensing. To utilize the advantages of Software Defined Radio (SDR) GNU Radio and USRP are used to capture the signal samples and store to a data file. Matlab communications toolbox is used to analyze the data and examine the spectrum. A number of theoretical analyses are available in literatures to detect the presence of signal. To investigate some of them from experimental perspective, we developed a spectrum sensing system with GNU Radio and USRP. GNU Radio based spectrum analyzers can be a cost effective solution for blind channel estimations also.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

AD変換器の高速化およびディジタルプロセッサの処理能力の進化に伴い,RF信号を直接AD変換して処理するダイレクトコンバージョン方式に基づいたソフトウェア無線技術が広く用いられている.ダイレクトコンバージョン方式では,RF信号の膨大なデータ処理のために,高速かつ高精度なディジタルフィルタが必要となるが,ディジタル実装時にフィルタの回路規模が問題となる.本稿では,このフィルタ演算の回路規模を減らすために,SPT項(Signed-Powers-of-Two Term)を用いてフィルタの乗算器係数を近似したFIRフィルタを設計し,FPGAで実装して,設計フィルタの回路規模の評価によりその有効性を検証する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Emergency communication systems are set to perform efficient rescue operations after disasters. Wireless communications is the only choice for these networks. After a natural disaster like earthquake in a metropolitan area, rescue operations must be quick and collaborative. Rescue teams setup their own emergency networks urgently. Checking the availability of the wireless channels in the disaster area is a time consuming and inconvenient solution. A spectrum sensing network that can detect the location and frequency of active emergency radio emitters in the disaster area can be helpful to avoid the interference among the rescue teams. This study discusses about the technologies and framework of such a spectrum sensing system for emergency communications.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

近年,Opportunisticな周波数の二次利用より周波数の効率的な利用を図るコグニティブ無線技術が注目をされるなか,既存システムに干渉を与えないために既存システムのスペクトル利用状況を高い確率で判断するスペクトルセンシング技術が重要な課題となっている.これまでに広帯域にまたがる複数のチャネルを同時にセンシングするための機構として,隣接チャネルからの電力漏れを抑えられるフィルタバンクを用いたセンシング機構が提案されてきている.フィルタバンクはバンドパスフィルタの効率的な実装を可能にすることから注目を集めているが,そのセンシング性能は十分に検討されていない.そのため本報告では,まずポリフェーズDFTフィルタバンクにエネルギー検出器を接続した複数チャネルセンシング機構を提案し,そのセンシング性能を理論的解析と数値シミュレーションで評価し,同時にフィルタ性能や各設計パラメータのセンシング性能に与える影響を検討した.また,従来のDFTによるピリオドグラム法,逐次的な単チャネルセンシングとの比較も行った.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では、ボディエリアネットワークにおける動的なチャネル特性に関して実際の人体にアンテナを装着して行った測定結果について報告する.本測定は,チャネル伝達関数の測定ためネットワークアナライザを使用し,444.5MHz,611MHz,953MHzの周波数,被験者2名、またオフィス環境を想定して測定を行った.また,静止・徒歩・立ち座りの動作モデルを想定し,送信点を臍付近に固定し,人体表面の10ヵ所において測定を行った.本報告では、主に動的なチャネル測定システムの構築について報告する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

近年,Opportunisticな周波数の二次利用より周波数の効率的な利用を図るコグニティブ無線技術が注目をされるなか,既存システムに干渉を与えないために既存システムのスペクトル利用状況を高い確率で判断するスペクトルセンシング技術が重要な課題となっている.これまでに広帯域にまたがる複数のチャネルを同時にセンシングするための機構として、フィルタバンクを用いたセンシング機構が提案されてきている.フィルタバンクはバンドパスフィルタの効率的な実装を可能にすることから注目を集めているが,そのセンシング性能は十分に検討されていない.そのため本報告では,まずポリフェーズDFTフィルタバンクにエネルギー検出器を接続したマルチチャネルセンシング機構を提案し,そのセンシング性能を理論的解析と数値シミュレーションで評価し,同時にフィルタ性能や各設計パラメータのセンシング性能に与える影響を検討した.また,従来のFFTによるセンシング,逐次的な単チャネルセンシングとの比較も行った.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

GNU Radio refers to some open source software which, together with low cost hardware called USRP, can be used to realize a software radio platform. Cognisant of the possible practical limitations inherent to GNU-radio technology, this research seeks to explore the suitability of this technology in realization of a software radio platform. A PN sequence based channel sounding system with two Linux based host PC and two USRPs configured in the Master - Slave mode, was therefore implemented as a target application.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

AD変換器の高速化およびディジタルプロセッサの処理能力の進化に伴い,RF信号を直接AD変換して処理するダイレクトコンバージョン方式に基づいたソフトウェア無線技術が広く用いられている.ダイレクトコンバージョン方式では,RF信号の膨大なデータ処理のために,高速かつ高精度なディジタルフィルタが必要となるが,ディジタル実装時にフィルタの回路規模が問題となる.本稿では,このフィルタ演算の回路規模を減らすために,SPT項(Signed-Powers-of-Two Term)を用いてフィルタの乗算器係数を近似したディジタルフィルタを設計し,FPGAで実装して,従来のフィルタとの回路規模の比較によりその有効性を検証する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

Spectrum sensing is an important functionality for secondary systems to ensure that they do not interfere primary systems when they try to access the unused spectrum of the primary systems. Energy detector is one of the possible candidates for spectrum sensing. In this paper, the important practical detection issues of spectrum sensing i. e. effect of quantization and effect of noise uncertainty on the performance of energy detector have been explored. Simulations have been carried out to show that both of these issues have significant effect on the overall performance of the detector. In addition, it has been shown that co-operative sensing helps to reduce those effects to some extent.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：[電子情報通信学会]  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

ETC料金所における実信号を用いたリアルタイムの多重到来波分離測定システムの開発を行ったので,そのハードウェア構成,測定原理,信号処理の概要に関して報告する.本システムは,ETCレーンを閉鎖せず,ETC基地局から実際に発射される電波を用いて,測定車により移動しながら測定可能である.空間的な電力分布の測定を行なうばかりでなく,多重到来波を分離して各到来波の散乱過程と強度を推定するものである.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では,低軌道周回衛星(low-earth-orbit; LEO)通信のための小型・低姿勢車載用アンテナとして,新たな構造を提案する.これは従来の線状逆Fアンテナ構造の変形を行い,ループ状のエレメントをもつ新たな構造(loop-shaped inverted-F wire antenna; LIFA)である.アンテナを小形化すると使用できる周波数帯域が減少するため,送受信周波数が離れている衛星通信用の用途では,狭帯域なアンテナを二共振として使用帯域を確保する必要がある.このアンテナは,ループ状の給電素子の中にループ状無給電素子を設けることにより二共振を起こし,デュアルモード動作が実現できる.本報告では,提案のアンテナ構造に関する基礎検討として,その動作原理と特性をモーメント法を用いて計算機シミュレーションと,試作実験による原理検証を行ったので報告する.

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）   出版者・発行元：CQ出版  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

ソフトウェア無線の受信系において,理想的な構成としてダイレクトRFサンプリングを用いた構成が挙げられる.しかし,RFサンプリングを行う場合,そのディジタルフロントエンドは,処理の高速化や回路規模の増大の問題が生じる.本稿では,RFサンプリングを用いたマルチモード受信機の構成を提案する.また,FPGA(Field Programmable Gate Array)を用いたADボードにより試作を行い,比較的小規模な回路により提案構成が実現され,復調がなされることを確認する.

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記述言語：日本語   掲載種別：記事・総説・解説・論説等（商業誌、新聞、ウェブメディア）   出版者・発行元：CQ出版  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

使用状況によりアンテナの入力インピーダンスが変化し,内部回路との間に不整合が生じる。その対策として複数の並列キャパシタを配置し,ピンダイオードによるON/OFF切り替えで離散的に回路パターンを作り出すディジタル可変キャパシタを用いた整合回路によってインピーダンスの変化に対応させる方法が考えられる。本報告では,より高速に最適点の検索を行う制御アルゴリズムを検討し,そのアルゴリズムをFPGAに実装を行った。そして,実際にシステム全体を構築し,実験によりその性能の確認を行った。

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

高速移動体通信の実現を可能にする手法としてMMSE (Minimum Mean Square Error)アダプティブアレーアンテナが挙げられる.MMSEアダプティブアレーは,干渉波や遅延波に対してアンテナ指向性のヌルを向けて抑圧し,所望波にはビームを向けることで所望信号のデータを取り出すことができる.主なMMSEアルゴリズムとして,LMS (Least Mean Square), RLS (Recursive Least Squares)アルゴリズムの最適化アルゴリズムがあり,RLSアルゴリズムはLMSアルゴリズムよりも収束が速いが演算量がアンテナ素子数の2乗に比例して増加することが問題になっていた.そこで,効率的な並列パイプライン処理を用いてギブンズ回転に基づくQRD-RLSアルゴリズムの計算を行うのがRLSシストリックアレーであり,RLSアルゴリズムに必要とされる処理時間を削減することができる.本稿ではLMS, RLS, QRD-RLSアルゴリズムのFPGA実装を同一ハードウェアに行い,回路規模と実時間での収束特性および固定小数点演算におけるビット依存性についての評価を行う.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

ソフトウェア無線の要素技術として複数のアンテナを用いて空間処理を行うアダプティブアンテナ技術が注目されている.本稿では16素子アレーアンテナを用いて到来方向推定を行う信号処理システムを紹介する.16素子アレーアンテナから受信された信号は同期サンプリングされ周波数変換後, MUSICアルゴリズムを用いて到来方向推定を行う.本システムはCPU(SH4, Hitachi)上にOSとしてNetBSDが移植された組込みシステムをベースに14ビット80MSPSのAD変換機と14ビット165MSPSのDA変換機がそれぞれ16機が搭載されているデータ処理基板と構成され, 基板上の大容量(100万ゲート×2)のFPGAで並列処理を行うような構成になっている.本稿では, Unitary MUSIC法をFPGAを用いて実装した構成についても紹介する.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

次世代高速移動通信のニーズに応じてアンテナの指向性を適応的に制御可能なアダプティブアレー技術の導入が有効である.筆者らは電波の到来方向を高速で推定可能な処理器を実装し適応指向性を生成する評価システムを試作した.本システムは,高速処理を行うため,FPGA(Field Programmable Gate Array)を用いた専用回路で実装されている.しかし,本システムの固定小数点演算の精度については定量的に確認する必要がある.本報告では,高速方向推定処理器の精度について定量的に調べ,推定された到来方向情報からのビーム形成法について検討する.さらに,特に計算量の少ないドルフチェビシェプ指向性を用いた低サイドローブビーム形成法について,その性能を確認する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

MMSE (Minimum Mean Square Error)アダプティブアレーアンテナを用いてマルチパスフェージングや干渉波の影響を軽減することが可能となる.MMSEアダプティブアレーアンテナには主に3つの最適化手法があり,その中でRLS (Recursive Least Squares)アルゴリズムは収束が早い利点が知られている.一方,RLSアルゴリズムは行列演算を含む計算量が多いという欠点がある.そこで,並列処理が可能なFPGA (Field Programmable Gate Array)を使用することで処理速度の向上を図ることが考えられる.しかし,FPGAは固定小数点演算が適しているため,固定のビット長でのRLSアルゴリズム処理にはその精度について検討が必要である.筆者たちは以前の文献において,シミュレーションから素子数を限定することにより固定小数点演算においても浮動小数点演算並みの推定精度が得られることを確認している.本稿では,シミュレーションにより得られた必要となる固定小数点のビット数をもとに,RLSアルゴリズムをFPGAに実装し,正弦波の場合での実験による検討を行う.また,MMSEアダプティブアレーに関しては同期処理という問題がある.本検討では,正弦波1波が入射した場合に同期を取るためのマッチトフィルタをFPGAに実装する.そして,同期処理器を用いたRLSアルゴリズムの正弦波による検討を行う.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

マルチパスフェージングの問題の解決や、SDMA(Space Division Multiple Access)方式の実現による周波数利用効率の向上に有効な下り回線の指向性制御を行えるシステムを試作した。このシステムは複数のFPGA(Field Programmable Gate Array)を搭載し、各アレーアンテナに必要な信号処理を並列に行う構成となっている。具体的には入力されたシリアルデータにQPSKマッピングを行い複素ウェイトを乗じた後にデジタルアップコンバートで直接IF信号を生成する回路をFPGAに実装を行った。本報告では、アダプティブアレーアンテナ送信機のデジタル部の実装について報告をする。

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

本報告では、アダプティブアレーアンテナの実装や評価のために試作した実験システムについて紹介する.本システムは以前開発したシステムより、チャンネル容量を増やし、また、問題点を改善した.このシステムは以前と同様に、実時間並列信号処理に対応する高性能、大容量のFPGA(Field Programmable Gate Array)で信号処理を行う.ソプトウェア無線のコンセプトに充実して、IF帯域の信号をサンプリングし、デジタルダウンコンバージョンをFPGAで実装している.本報告では、本システムの設計方針や特徴について説明し、最大比合成ビームフォーマを実装することにより、その動作を確認する.

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

本報告ではFPGA(Field Programmable Gate Array)を用いたデジタル処理部を実装し、次世代移動通信に不可欠なリアルタイム処理に向いた簡単な最大比合成ビームフォーミングアンテナの実装について検討する。FPGAとはコンフィグレーション可能なCPLDの一種であり、DSP(Digital Signal Processor)の持つプログラマブールな特性とASIC(Application Specific Integrated Circuit)の高性能のメリットを両方共に持っている。FPGAは将来デジタルビームフォーミングなどの高速リアルタイム性が要求される色々なアプリケーションに大きな役割をすることが予想される。本報告ではFPGA基盤のDSP処理機の実装について報告する。そして電波暗室での実験結果を紹介する。

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記述言語：英語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-26  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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開催地：5D-2  

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記述言語：英語   会議種別：口頭発表（一般）  

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開催地：B-1-26  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：4A-1  

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記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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開催地：B-1-141  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-30  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-31  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Busan, Korea  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Busan, Korea  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：BS-8-1  

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開催地：4B-3  

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開催地：P1-24  

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開催地：BS-1-7  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Toyama, Japan  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Jeju, Korea  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：MICT2018-4  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：MICT2017-55  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-20-3  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-31  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Sydney, Australia  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：SRW2017-82  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Niigata, Japan  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Niigata, Japan  

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開催地：4D-3  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：BS-8-2  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-27  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Busan, Korea  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Busan, Korea  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Sapporo, Japan  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Paris, France  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：SRW2016-6  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Paris, France  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-32  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：B-1-31  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：SRW2016-97  

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記述言語：英語   会議種別：口頭発表（一般）  

開催地：Lisbon, Portugal  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：MICT2016-74  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：4B-3  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：3C-1  

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記述言語：日本語   会議種別：口頭発表（一般）  

開催地：SR2016-64  

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