Updated on 2024/06/24

写真a

 
SHIMAMOTO, Shigeru
 
Affiliation
Faculty of Science and Engineering, School of Fundamental Science and Engineering
Job title
Professor
Degree
工学修士 ( 電気通信大学 )
Master of Electro Engineering
工学博士 ( 東北大学 )
Doctor of Engineering
博士(工学) ( 東北大学 )

Research Experience

  • 2020.10
    -
    Now

    Global Information and Telecommunication Institute   Director

  • 2014.04
    -
    Now

    Communication and and Computer Engineering, Waseda Univeristy   professor

  • 2002.04
    -
    2014.03

    Global Information and Telecommunication Studies, Waseda univeristy   professor

  • 2008.07
    -
    2008.12

    Stanford University   Electrical Engineering   Visiting Professor

  • 2000.04
    -
    2002.03

    Graduate school of Information and Telecommunication Studies, Waseda univeristy   Associate Professor

  • 1994
    -
    2000

    Gunma Univ., Associate Prof.

  • 1992
    -
    1994

    Gunma Univ., Research Assistant.

  • 1990
    -
    1992

    Univ. of Electro Communication, Research Assistant

  • 1987
    -
    1990

    NEC

▼display all

Education Background

  •  
    -
    1987

    University of Electro-Communications   Graduate School, Division of Electro Communications  

  •  
    -
    1985

    University of Electro-Communications   Faculty of Electro Communications  

Professional Memberships

  •  
     
     

    電子情報通信学会

  •  
     
     

    IEEE

  •  
     
     

    情報処理学会

  •  
     
     

    IEICE

Research Areas

  • Information network

Research Interests

  • Ultrasonic Communication

  • Vital Sensing

  • Optical Wireless Communication

  • Air to Ground Communication

  • Satellite Communication

  • Wireless Communication

▼display all

 

Papers

  • A Lightweight Integrated Narrowband Interference Detection and Suppression Scheme for OTFS

    Yuchen Wu, Zhenni Pan, Shigeru Shimamoto

    IEEE Vehicular Technology Conference   2023-June  2023

     View Summary

    Orthogonal Time Frequency Space (OTFS) has been proven to have strong robustness to Doppler shifts and is regarded as a potential candidate for Orthogonal Frequency Division Multiplexing (OFDM) in the next generation wireless communication. However, narrowband interference (NBI) may become a headache for OTFS-based wireless systems. In OTFS, NBI will be spread over the whole delay-Doppler (DD) domain, and thus cause serious interference. Such interference is very dangerous in OTFS-based high-mobility communication for it will let the fast-moving user equipment (UE) in danger of losing control. Previous work infers OTFS to have natural robustness to NBI. In this work, we conduct further analysis and come to the conclusion that such robustness is only capable when NBI is weak, but when NBI gets stronger, OTFS exhibits vulnerability to it. Then we propose an NBI suppression scheme for OTFS to detect and eliminate NBI with a low computation load. Simulation results prove our analysis and indicate the proposed scheme can prevent serious interference resulting from NBI to some extent.

    DOI

    Scopus

  • Joint Active and Passive Beamforming Optimization in Self-sustainable RIS-aided NOMA Networks

    Yiding Li, Zhenni Pan, Shigeru Shimamoto

    IEEE Vehicular Technology Conference    2023

     View Summary

    Reconfigurable Intelligent Surface (RIS) is a competitive technology for future communication systems owning its capability of artificially manipulating the Electro-Magnetic (EM) environment at a low energy cost. Self-sustainable RIS, as a practical design, further enhance the ease of deploying and maintaining the devices. In this paper, we discuss the joint active and passive beamforming design of a Wireless Power Transfer (WPT) powered self-sustainable RIS aided Non-Orthogonal Multiple Access (NOMA) system. An RIS-NOMA transmission scheme and a corresponding min-max fairness problem are proposed. To address the problem and tackle the non-convexity caused by the coupling of active and passive beamforming parameters, we discuss an Alternating Optimization (AO) based solution. Results show the tradeoff between self-sustainability and Spectrum Efficiency (SE) under different RIS settings. It is also determined that self-sustainable RIS and NOMA are mutual beneficial and allow higher SE compared with the combination with traditional OMA schemes.

    DOI

    Scopus

  • Non-contact Blood Pressure Prediction Employing Microwave Reflection based on Machine Learning

    Hinako Ochi, Jiang Liu, Shigeru Shimamoto

    Proceedings - IEEE Consumer Communications and Networking Conference, CCNC   2023-January   696 - 697  2023

     View Summary

    The typical measurement method using a cuff is physiologically stressful for many, especially the elderly people. In order to eliminate the burden and realize comfortable measurements, a non-contact method for monitoring blood pressure is necessary. This paper proposes a non-contact method to detect the human pulse, acceleration pulse waveform and in turn, predict blood pressure. In the experiment, microwave signals were transmitted against, and reflected from the chest and wrist, upon which the time-varying Insertion loss of Scattering parameter(S21) was acquired. Pulse, respiration rate and Augmentation Index(AIx) are first estimated via postprocessing of acquired raw data. Further signal processing also detects the acceleration pulse waveform. Blood pressure is then predicted via Machine Learning (ML) methods with parameter values derived from the detected pulse waveform, respiration waveform and acceleration waveform. Our works indicate that our proposed non-contact method is practical and has great potential for future smart health solutions.

    DOI

    Scopus

    1
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  • Machine Learning based on Air-writing Recognition System

    Yuao Ye, Jiang Liu, Wen Zhao, Peng Liu, Shigeru Shimamoto

    Proceedings - 2023 International Conference on Intelligent Computing and Control, IC and C 2023     13 - 18  2023

     View Summary

    With the development of the Internet of Things, new devices need more diversified input methods. Gesture recognition has become a hot research field, and air-writing [1] is a significant part of the field of gesture recognition. In our previous air writing recognition system, we proposed an input system that measures dynamic data based on an inertial measurement unit that uses a dynamic time warping (DTW) algorithm for recognition. In this paper, cDTWw algorithm, KNN & DTW classification algorithm and fastDTW algorithm are used for comparative experiments. In order to improve the actual recognition ability of the air writing system, save the recognition time as much as possible , and optimize the recognition accuracy. We found that the cDTW w algorithm has a faster recognition speed than the fastdtw algorithm in the air writing recognition system. KNN & DTW class fication algorithm significantly improves the recognition accuracy in the air writing recognition system.

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    Scopus

  • D2D Communication-Based Salvage Transmission Scheme for Communication Disturbance in 5G Networks

    Megumi Saito, Liu Jiang, Pan Zhenni, Shigeru Shimamoto

    Proceedings - IEEE Consumer Communications and Networking Conference, CCNC   2023-January   997 - 998  2023

     View Summary

    This study proposes a salvage transmission (ST) scheme for 5G networks using device-to-device (D2D) communication. In mobile networks, communication is disabled when issues emerge in the core network or base station of the operator. To address this problem, the proposed scheme provides mobile communication services via D2D communication to user equipment (UE) that cannot use cellular networks. The users of an operator that is unable to provide service due to communication failure transmit signal using D2D communication with the closest UE of another operator. This ST scheme enables the mitigation of communication failures. In addition, this study introduced the basic protocols of ST with Wi-Fi Direct (IEEE 802.11) and 5G networks. Furthermore, we verified the effectiveness of the ST scheme in the case of communication failures via a simulation study.

    DOI

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  • Performance Analysis of DSSS-PDMA with SIC in GEO Satellite-Terrestrial Uplink Networks

    Yosuke Higasa, Kazutoshi Yoshii, Megumi Saito, Jiang Liu, Shigeru Shimamoto, Takuya Okura, Naoko Yoshimura, Amane Miura, Hiroyuki Tsuji, Morio Toyoshima

    International Conference on Advanced Communication Technology, ICACT   2022-February   1 - 6  2022

     View Summary

    There is a growing trend to utilize satellite networks for the construction of 5G and Beyond 5G high-capacity systems. The power division scheme used in non-orthogonal multiple access (NOMA), which is a key technology for terrestrial networks, can contribute to improving the system capacity of satellite networks. In this paper, we propose a direct sequence spread spectrum-power level division multiple access (DSSS-PDMA) scheme that combines non-orthogonal PDMA with DSSS technology to mitigate the depletion of communication resources and interference to terrestrial terminals. Finally, simulation results with ETS-9 as the high throughput satellite (HTS) and active electronically scanned array (AESA) antenna as the earth station validate the effectiveness and superiority of the proposed schemes as compared with several existing schemes.

    DOI

    Scopus

    1
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  • Multi-layer Constellation based Is-OWC employing NOMA

    Wataru Tachikawa, Ajgaonkar Swarali Ashish, Kazutoshi Yoshii, Jiang Liu, Shigeru Shimamoto

    2022 IEEE International Conference on Space Optical Systems and Applications, ICSOS 2022     100 - 106  2022

     View Summary

    Inter-Satellite Optical Wireless Communication (Is-OWC) is regarded as the best choice for satellite communication because of its large throughput, low transmission power and high immunity to interference. To increase the availability of Is-OWC, it is required to implement a communication scheme that realizes lower latency and handles more traffic. In this paper, we propose a new Is-OWC system that uses multi-layer satellite constellation that applies uplink Non-Orthogonal Multiple Access (NOMA) to achieve delay suppression and increased throughput. In our proposed scheme, to distribute packets and reduce queue delay in each satellite, each communication path is adapted to the distance between the terrestrial transmitter and receiver. Simulation results validate the performance of our NOMA model is better than that of the conventional OMA model. Furthermore, the results showed that the BER of our model is improved by introducing the original algorithm to optimize the transmission power and the allocated sub-band of each satellite for the NOMA transmission. As a result, comparison of the latency between the proposed model using LEO and MEO satellites and the conventional model using only LEO satellites, the proposed model realizes delay suppression. The difference between the two models becomes more significant as the number of sessions in the entire network increases.

    DOI

    Scopus

    2
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  • Recognition of Japanese Sign Language by Sensor-Based Data Glove Employing Machine Learning

    Li Ji, Jiang Liu, Shigeru Shimamoto

    LifeTech 2022 - 2022 IEEE 4th Global Conference on Life Sciences and Technologies     256 - 258  2022

     View Summary

    This paper presents a sensor-based data acquisition glove for gesture recognition in Japanese Sign Language (JSL), which uses five flex sensors and an inertial measurement unit (IMU) to detect finger flexion and hand motion information. The detected data is sent from the Arduino Micro to a computer. We collected data from the "A"to "Ta"lines of the Japanese (kana) syllabary and using four different machine learning algorithms: Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF), and K-Nearest Neighbor (KNN) to recognize them. RF and KNN have the highest average accuracy, reaching 99.75%. Also, SVM and DT had an average accuracy of 99% and 94.25% respectively. The experimental results show that the proposed system has great potential for gesture recognition in Japanese Sign Language.

    DOI

    Scopus

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  • Radio and Power over Double Clad Fiber System for 4K/8K Satellite Broadcasting

    Zixuan Guo, Jiang Liu, Shigeru Shimamoto

    Proceedings - IEEE Consumer Communications and Networking Conference, CCNC     507 - 508  2022

     View Summary

    With the increasing number of 4K/8K channels and the development of broadcasting technology, the frequency used for the intermediate frequency (IF) signal keeps increasing. Using fiber to replace cable is proved to achieve lower signal loss and reduces the noise sensitivity in 4k/8k broadcasting systems. Power-over-fiber (PoF) is chosen for the power supply. In this research, a 4K/8K broadcasting system using double-clad fiber (DCF) to maintain power and signal transfer simultaneously is proposed. DCF has three layers and can achieve Single-Mode and Multi-Mode transmission simultaneously. The breakthrough we make is using HPLD for energy supply to combine RoF and PoF together.

    DOI

    Scopus

  • Non-contact Blood Pressure Estimation By Microwave Reflection Employing Machine Learning

    Hinako Ochi, Jiang Liu, Shigeru Shimamoto

    Proceedings - IEEE Consumer Communications and Networking Conference, CCNC     889 - 892  2022

     View Summary

    In recent years, hypertension has become a leading cause of diseases worldwide. Despite the recommendation from medical experts to measure blood pressure on a daily basis, only a small few do so. The main reason for this is that the typical measurement method using a cuff is physiologically stressful for many, especially for physically handicapped people, and the elderly. In order to eliminate the burden during measurement, a non-contact method for monitoring blood pressure is necessary. This paper proposes a non-contact method to detect the human pulse and in turn, estimate blood pressure. In the experiment, 2.4GHz microwave signals were transmitted against, and reflected from the body, upon which the time-varying reflection intensity was acquired. Pulse rates are first estimated via post-processing of acquired raw data. Blood pressure is then estimated via Machine Learning (ML) methods with parameter values derived from the detected pulse waveform. Experiments indicate that our proposed method is practical and has great potential for future smart health solutions.

    DOI

    Scopus

    3
    Citation
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  • A Lightweight Network Slicing Scheme for 5G Coexistence Network in Multitenant and Services

    Tianshun Fang, Hao Xue, Zhenni Pan, Shigeru Shimamoto

    2022 International Symposium on Networks, Computers and Communications, ISNCC 2022    2022

     View Summary

    Resource allocation of 5G cellular network slicing has been gaining huge interest recently. However, it is not well-explored under the Multi-tenant and Multi-service Coexistence Network scenario. This paper proposes a dynamic network slicing scheme for the 5G Coexistence Network, which considers tenants, priority, baseband resources, slice granularity, service characteristics, quality of service (QoS), and fairness index. The framework of the network slicing scheme consists of a group-level, which performs clustering preprocessing, setting the priority of service, and filtering the desired characteristic service groups; and a slice-level, which performs radio resource allocation among services and follows the changes in the network environment closely. The simulation results show that the proposed scheme can achieve higher goal service group QoS, fairness, and overall QoS compared with three kinds of baseline schemes.

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    Scopus

  • Performance Analysis of Intelligent Reflecting Surface-Assisted Orbital Angular Momentum-Based Communication Systems

    Kosei Ono, Kazutoshi Yoshii, Megumi Saito, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    International Conference on Advanced Communication Technology, ICACT   2022-February   7 - 12  2022

     View Summary

    Uniformed circular array antenna (UCA) based orbital angular momentum (OAM) communication system has some disadvantages, such as not being suitable for long-distance multiplexing and requiring a high degree of synchronization between the transmitting and receiving antennas. To achieve non-line-of-sight (NLoS) communication using OAM radio waves, we propose an inter-mode interference (IMI) cancellation method for intelligent reflecting surface (IRS)-Assisted OAM multiplexing to eliminate the IMI from all OAM modes. We also propose a L2-ba11 projection method to optimize the transmit power allocation for OAM modes to increase the system capacity of IRS-assisted OAM communication systems. The IMI cancellation method and the L2-ball projection method are shown to achieve increasing the maximum system capacity as compared to the L1-ball projection method when the IRS is located closer to the middle between the transmitter UCA and receiver UCA.

    DOI

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    2
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  • Sign language estimation scheme employing Wi-Fi signal

    Changhao Liu, Jiang Liu, Shigeru Shimamoto

    2021 IEEE Sensors Applications Symposium, SAS 2021 - Proceedings    2021.08

     View Summary

    The sign language recognition system plays an important role in the field of human-computer interaction. In the daily life of hearing-impaired people, sign language is used as the main tool to communicate with the world. Although sign language can satisfy simple conversation, it is difficult to deal with in some situations where a lot of conversation is required such as medical emergencies or educational consultation. This paper proposes a sign language recognition system based on Wi-Fi to improve the life of the disabled The proposed system collects the Channel State Information (CSI) due to the change of hand movement. Through the analysis of all subcarriers, the amplitude of CSI is determined to reflect the characteristics of different sign languages, some high-frequency noise is removed in the amplitude of CSI to obtain a smoother signal Gesture feature. We propose a gesture feature extraction method based on the variance of time series and DTW algorithm is used to recognize nine common Japanese sign language gestures. We set two daily conditions to test the system, and the experimental results show that the system performs well in different conditions.

    DOI

    Scopus

    2
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  • Non-contact Blood Pressure Estimation with Pulse Wave employing Microwave Reflection

    Hinako Ochi, Shigeru Shimamoto, Jiang Liu, Yukino Yamaoka

    2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021 - Proceedings    2021.06

     View Summary

    Nowadays it is recommended to do blood pressure measurements on a daily basis at home to prevent diseases caused by high blood pressure. Blood pressure measurements methods using a cuff is most commonly used. However, it is a burden for hypertensive patients and the elderly to put on a blood pressure cuff repeatedly for the multi-metering of blood pressure. Non-contact measurement will provide a comfortable and easy method to monitor blood pressure and pulse rates continuously. This paper proposes a non-contact method to measure both pulse rates and blood pressure simultaneously. In the experiment, microwave signals were transmitted to the body and the reception intensity was measured. The microwave frequencies used in this experiment were 2.4GHz and 5.6GHz. The pulse rates and the blood pressure can be estimated by processing the data obtained from microwave reflection. The experiment results show that the 2.4GHz microwave signals have better estimation accuracy. It indicates that our proposed system is practical and has great potential for the future smart health monitoring system.

    DOI

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    4
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  • A sensor-based hand gesture recognition system for Japanese sign language

    Xianzhi Chu, Jiang Liu, Shigeru Shimamoto

    LifeTech 2021 - 2021 IEEE 3rd Global Conference on Life Sciences and Technologies     311 - 312  2021.03

     View Summary

    In this paper, we propose a sensor-based data acquisition glove for Japanese Sign Language (JSL) hand gesture recognition. Five flex sensors, an Inertial Measurement Unit (IMU), and three Force Sensing Resistors (FSRs) are used to detect the bending degree of fingers and hand movement information. The detected data are transmitted to the computer by an Arduino Micro. The average accuracy of the hand gesture recognition for a single subject, using the Support Vector Machine (SVM) based and the Dynamic Time Wrapping (DTW) based algorithm are 96.9% and 94.5%, respectively. Our proposed system also achieves an average recognition accuracy of about 82.5% for the cross-recognition among three subjects. The experimental results indicate that our proposed system has great potential for JSL hand gesture recognition.

    DOI

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  • Wearable Air-Writing Recognition System employing Dynamic Time Warping

    Yuqi Luo, Jiang Liu, Shigeru Shimamoto

    2021 IEEE 18th Annual Consumer Communications & Networking Conference (CCNC)    2021.01

    DOI

  • Wireless Power Transmission Scheme Employing Phase Control for WSN

    Genta Ishii, Megumi Saito, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    2021 IEEE 18th Annual Consumer Communications & Networking Conference (CCNC)    2021.01

    DOI

  • Value Estimation of SpO2 Using a Non-Contact Method

    NAGAO Yoshimitsu, GAO Yanan, LIU Jiang, SHIMAMOTO Shigeru

    The Journal of the Institute of Image Electronics Engineers of Japan   50 ( 3 ) 439 - 443  2021

    DOI

  • Energy Borrowing Transmission Scheme Based on D2D Communication for 5G Networks

    Megumi Saito, Takashi Koshimizu, Zhenni Pan, Jiang Liu, Hayato Nakazawa, Shigeru Shimamoto

    IEEE ACCESS   9   165841 - 165853  2021

     View Summary

    In our paper, we proposed an Energy Borrowing (EB) transmission scheme which is used to conserve the battery life of user equipment (UE), such as a mobile phone. EB is based on device-to-device (D2D) communication and cellular networks, particularly, on out-band D2D (Wi-Fi Direct, IEEE 802.11) and 5G networks. Since D2D offers higher energy efficiency than cellular networks, in this scheme, a UE with low remaining battery power establishes a D2D connection with a nearby UE, and the nearby UE transfers the low remaining battery UE's packets to/from gNB (5G-base station). As nearby UE plays an active role in the low remaining battery UE's connection with gNB. Therefore, we can rephrase that a UE with low battery power is virtually borrowing the battery resources of a nearby UE. This paper introduces the operation protocol and procedure followed by EB with the use of Wi-Fi Direct and 5G networks. Experiments and simulations demonstrate that EB can extend terminal battery lifetime (a valuable characteristic for long-lasting batteries), and it is more effective as compared with the existing scheme that uses only the cellular network.

    DOI

    Scopus

    1
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  • Radio and Power over Fiber System for 4K/8K Satellite Antenna

    Ziyu Guo, Jiang Liu, Shigeru Shimamoto

    2020 IEEE International Conference on Communication, Networks and Satellite (Comnetsat)    2020.12

    DOI

  • Robotic inner signal propagation and random access over hybrid access scheme

    Md Abir Hossain, Zhenni Pan, Megumi Saito, Jiang Liu, Shigeru Shimamoto

    International Journal of Computer Networks and Communications   12 ( 4 ) 71 - 89  2020.07

     View Summary

    This paper proposes a Hybrid Access Scheme (HAS) aiming to convert a future robot's backend communication system by a finite number of sensors instead of using a lot of wires. To replace this communication, the HAS needs to assure higher reliability within stringent low latency packet transmission. In this paper, the HAS utilizes the packet diversity principle and forward multiple copies of the same packet over the massive number of subcarrier channels. The HAS assigns the random accessing to select a subcarrier channel for general packet transmitting sensors. The audio and video sensors transmit packets over the dedicated channels to avoid collisions. The HAS system allows transmitting audio, video and general sensors simultaneously. The minimum number of subcarriers to satisfy the URLLC reliability requirement of 99.999% is evaluated for different packet duplications over different arrival condition. The HAS system's reliability and collision probability are evaluated in MATLAB simulator for different packet duplication over different arrival condition. Moreover, the signal propagation expressions are captured using ANSYS HFSS software for rectangular and circular transmission medium over the 900 MHz, 2.4 GHz, 24 GHz, and 55 GHz frequency bands for different structural configurations.

    DOI

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    1
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  • Power Control Based on Multi-Agent Deep Q Network for D2D Communication

    Shi Gengtian, Takashi Koshimizu, Megumi Saito, Pan Zhenni, Liu Jiang, Shigeru Shimamoto

    2020 International Conference on Artificial Intelligence in Information and Communication (ICAIIC)    2020.02

    DOI

  • Phase Control Scheme to Reduce Ionospheric Fading for Long Distance HF Communication

    Kazutoshi Yoshii, Megumi Saito, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    12TH WIRELESS DAYS CONFERENCE (WD 2021)    2020

     View Summary

    The dynamic phase control system for the stable long distance high frequency (HF) communication is evaluated in this paper by the ionospheric propagation simulations. The radio wave in HF band reaches to the very far side on the Earth by ionospheric propagation. It is efficacious to low latency long distance communication and emergency communication, but the ionospheric propagation is the cause of a phase fluctuation and power attenuation, the affects lead to ionospheric fading that is the sharp drop of the received power. We have reproduced the HF band propagation in a computer simulation and calculated the received power at the receiving station. The results show the improvement of the received power and fading reduction by the appropriate phase control at transmission station.

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  • A Triple-Band Antenna Loaded with Reflector Surface for WLAN and 5G Applications

    Tengfei Hu, Zhenni Pan, Megumi Saitou, Jiang Liu, Shigeru Shimamoto

    Journal of Communications     729 - 734  2020

     View Summary

    In this paper, a novel triple-band antenna with reflector surface which has the property of both artificial magnetic conductor (AMC) surface and perfect electric conductor (PEC) for WLAN and Sub-6G 5G applications is proposed. The presented antenna is composed of two parts: the AMC surface and the microstrip-fed printed dipole. Baluns are used to excite the dipoles. This antenna design combines the advantages of AMC and PEC. In lower band and middle band, the inserted board works as AMC surface. This AMC surface can help the antenna to achieve unidirectional radiation pattern and low-profile characteristics. While at upper band the antenna works as PEC surface. PEC surface increases the gain of the antenna in upper band. As a result, the proposed antenna can offer an impedance band from 2.39 GHz to 2.63 GHz and from 3.61 GHz to 3.72 GHz and from 5.61 GHz to 5.84 GHz when the S11 is less than - 10dB. Stable radiation patterns with peak gain of 5.6 dBi, 6.5 dBi and 9.6 dBi are obtained in lower band, middle band and upper band, respectively. The proposed antenna can be used for multiband base stations for WLAN and 5G applications.

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  • Multi-Dimensional Affinity Propagation Clustering Applying a Machine Learning in 5G-Cellular V2X

    Takashi Koshimizu, Shi Gengtian, Huan Wang, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEEE Access   8   94560 - 94574  2020

    DOI

  • Multiband Massive Channel Random Access in Ultra-Reliable Low-Latency Communication

    Abir Hossain, Zhenni Pan, Megumi Saito, Jiang Liu, Shigeru Shimamoto

    IEEE Access   8   81492 - 81505  2020

    DOI

  • Value Estimation of SpO2 Using a Non-Contact Method : Comparison with a Contact Method

    NAGAO Yoshimitsu, GAO Yanan, LIU Jiang, SHIMAMOTO Shigeru

    IIEEJ Transactions on Image Electronics and Visual Computing   7 ( 2 ) 142 - 150  2019.12

     View Summary

    It is impossible to estimate arterial oxygen saturation (i.e., SpO2) for individuals by using conventional approaches unless the given sensor of the pulse oximeter is attached to an individual’s finger. This study introduces a novel method to solve this problem. This study has focused on realizing SpO2 measurements by using non-contact space measurements, and the success of the approach is validated through experiments. Finally, despite a few problems including the susceptibility of the proposed approach to other light interference, the study offers an initial method to utilize laser wavelengths for the fore-mentioned purposes. As the characteristic of elderly individuals involves the hardening of the fingertips’ skin, it is difficult for the light of a probe to enter the same. Therefore this study can be applied to medical care, elder care, and other related fields. .Additionally, there are cases that symptoms are unmeasurable. The light receiving property to other light interference in space constitutes a problem for the fore-mentioned method.

    DOI CiNii

  • Design of Ultrasonic Wireless Power Transfer System

    Kensuke Nagaya, Jiang Liu, Shigeru Shimamoto

    2019 IEEE Globecom Workshops (GC Wkshps)    2019.12

    DOI

  • Prediction of Ionospheric Fading for Long Distance Emergency Communication

    Kazutoshi Yoshii, Megumi Saitou, Jiang Liu, Shigeru Shimamoto

    2019 IEEE International Conference on Communications Workshops (ICC Workshops)    2019.05

    DOI

  • MMLPA: Multilayered Metamaterial Low Profile Antenna for IoT Applications

    Rakotoaritina Tojoarisoa, Saito Megumi, Pan Zhenni, Liu Jiang, Shimamoto Shigeru

    Journal of Advanced Simulation in Science and Engineering   6 ( 1 ) 273 - 281  2019

     View Summary

    Nowadays, within the concept of Internet of Things (IoT), smart homes, smart factory, intelligent transportation among others are infrastructure systems that connect our world to the Internet. However, wireless communications technology are considerably constrained by complicated structures, and lossy media in complex environments. Fundamental limitations on the transmission range have been treated to connect IoT devices in such Radio Frequency (RF) challenging environments. In order to extend the transmission range in complex environments, Magnetic Induction (MI) communication has been proved to be an efficient solution. In this paper, a Multilayered Metamaterial low profile antenna (MMLPA) using Magnetic Induction communication scheme is proposed for IoT applications. The system model of the MMLPA is analyzed. Then an MMLPA system is designed by using a circular loop antenna backed with isotropic metamaterial which is considered as a Defected Ground Structure (DGS) as well as with anisotropic metamaterial for the purpose of a dielectric uniaxial metamaterial. By using a full-wave finite-element method, the proposed analysis is supported with simulation results where good agreement is achieved compared to the measurement results after realizing four prototypes of the MMLPA antennas. The effect of the presence of metal in the vicinity of the transceivers is also analyzed.

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  • Non-invasive Glucose Measurement Based on Ultrasonic Transducer and Near IR Spectrometer

    Yanan Gao, Yukino Yamaoka, Yoshimitsu Nagao, Jiang Liu, Shigeru Shimamoto

    Lecture Notes in Electrical Engineering     33 - 40  2019

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  • $P$ -Persistent Energy-Aware Handover Decisions Employing RF Fingerprint for Adaptive-Sized Heterogeneous Cellular Networks

    Zhenni Pan, Megumi Saito, Jiang Liu, Shigeru Shimamoto

    IEEE Access   7   52929 - 52944  2019

    DOI

  • Energy splitting for swipt in Qos-constraint MTC network: A non-cooperative game theoretic approach

    Kang Kang, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    International Journal of Computer Networks and Communications   10 ( 5 ) 105 - 116  2018.09

     View Summary

    This paper studies the emerging wireless energy harvesting algorithm dedicated for machine type communication (MTC) in a typical cellular network where one transmitter (e.g. the base station, a hybrid access point) with constant power supply communicates with a set of users (e.g. wearable devices, sensors). In the downlink direction, the information transmission and power transfer are conducted simultaneously by the base station. Since MTC only transmits several bits control signal in the downlink direction, the received signal power can be split into two parts at the receiver side. One is used for information decoding and the other part is used for energy harvesting. Since we assume that the users are without power supply or battery, the uplink transmission power is totally from the energy harvesting. Then, the users are able to transmit their measured or collected data to the base station in the uplink direction. Game theory is used in this paper to exploit the optimal ratio for energy harvesting of each user since power splitting scheme is adopted. The results show that this proposed algorithm is capable of modifying dynamically to achieve the prescribed target downlink decoding signal-to-noise plus interference ratio (SINR) which ensures the high reliability of MTC while maximizing the uplink throughput.

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  • Traffic-Aware Energy Optimizing Strategies for Multi-Cell Coordinated Green Cellular Networks

    Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEEE Transactions on Green Communications and Networking   2 ( 2 ) 418 - 431  2018.06

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  • Fairness-aware hybrid resource allocation with cross-carrier scheduling for LTE-U system

    Yupu Dong, Zhenni Pan, Kang Kang, Jiang Liu, Shigeru Shimamoto, Ragil Putro Wicaksono, Seiji Kunishige, Kwangrok Chang

    Lecture Notes in Electrical Engineering   425   114 - 128  2018

     View Summary

    Recently, the 3rd Generation Partnership Project (3GPP) proposes to extend the Long Term Evolution Advanced (LTE-A) to the unlicensed spectrum, named Long Term Evolution Unlicensed (LTE-U), which enables LTE to operate in both the licensed band and the unlicensed band. In this paper, we consider how to make LTE-U get even higher throughput in the high traffic unlicensed band. In order to achieve this target, there is a big challenge to make LTE-U a good neighbor to the existing wireless communication technologies in the unlicensed band, such as WIFI system in the 5 GHz band. In our research, we assume two carriers aggregated, one is from licensed band, and the other is from unlicensed. We also define two kinds of frequency resources in the unlicensed band. One is the normal frequency resource that has not been utilized by the WIFI systems, and the other is the special frequency resource that has been utilized by the WIFI systems already. We propose a novel hybrid resource allocation algorithm by combining two different frequency sharing schemes (Underlay and Interweave) and apply different resource allocation algorithm to achieve higher throughput for all kinds of user equipment (UE) from LTE-U when the WIFI system’s traffic is heavy. We also consider the fairness for all UEs from LTE-U system and guarantee that the interference to the WIFI UEs (WUEs) is acceptable.

    DOI

    Scopus

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  • Novel UE RF condition estimation algorithm by integrating machine learning

    Yupu Dong, Zhenni Pan, Mohamad Erick Ernawan, Jiang Liu, Shigeru Shimamoto, Ragil Putro Wicaksono, Seiji Kunishige, Kwangrok Chang

    Lecture Notes in Electrical Engineering   425   102 - 113  2018

     View Summary

    By 2020, 5G era will be commercially available. The smart city construction will also make great progress. Compared to current situation, more than thousand times of devices will connect to the cellular networks. For the operators, in order to analyze overall network performance, it is a key factor to estimate the user equipment (UE) radio frequency (RF) condition. However, practical RF estimation scheme is based on UE data log which can only observe UE that is at the top-serving cell with good RF condition. However, according to the comparison of actual UE data log and the scanner data log, potential RF problems may still exist since the UE will not always be served by the top-1 cell. In this paper, we propose a novel estimation scheme by integrating machine learning (ML) algorithm to analyze the scanner data logs from the target estimation zones where the mobility problems may occur. A hypothesis is obtained from learning step by various kinds of RF condition as input features. The numerical results show that the proposed estimation algorithm integrated ML can estimate probability of the potential mobility problems accurately.

    DOI

    Scopus

  • Full-Duplex Wireless Powered IoT Networks

    Kang Kang, Rong Ye, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEEE ACCESS   6   53546 - 53556  2018

     View Summary

    This paper studies the emerging wireless power transfer for the Internet-of-Things (IoT) network, where one hybrid access point (H-AP) with constant power supply communicates with a set of IoT devices. This H-AP is assumed to work in a full-duplex mode, which transmits/receives signals to/from these IoT devices simultaneously during the whole frame. The IoT devices are capable of harvesting energy from the received signals broadcast by the H-AP. And the harvested energy is used to support the uplink transmission. Since time-division multiple access is used in uplink transmission, one IoT device keeps harvesting energy till its own uplink time slot. The objective of this paper is to maximize the total surplus energy, which is defined as the gap between available energy and consumed energy for uplink transmissions, by exploiting the optimal time allocation scheme for each device. A distributed non-cooperative and a bargaining cooperative game-based algorithms are proposed to solve this problem. In addition, the well-known KKT condition approach is adopted as a comparison. The numerical results show that the bargaining cooperative algorithm outperforms the distributed non-cooperative algorithm (DNCA) and KKT algorithm (KKTA) in terms of total surplus energy and fairness index. The performance of DNCA is better than that of KKTA in terms of total surplus energy while KKTA is fairer than DNCA.

    DOI

    Scopus

    4
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  • 3D radio signal visualization employing drone

    Ryota Hagiwara, Hikari Inata, Yukihiko Okouchi, Jiang Liu, Shigeru Shimamoto

    2018 15th IEEE Annual Consumer Communications & Networking Conference (CCNC)    2018.01

    DOI

  • A Game Theory Based Power Control Algorithm for Future MTC NOMA Networks

    Kang Kang, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    2017 14TH IEEE ANNUAL CONSUMER COMMUNICATIONS & NETWORKING CONFERENCE (CCNC)     203 - 208  2017

     View Summary

    In this paper, we propose a power control algorithm dedicated for machine type communications (MTC) in future non-orthogonal multiple access (NOMA) networks employing game theory. In MTC networks, communication reliability should be considered prior to power consumption or energy efficiency. Once the reliability is satisfied, discussions about power consumption makes sense. We build a cost function for each device based on a non-cooperative game model. The cost function reflects the power consumption as well as received signal-to-interference plus noise ratio (SINR) of each device. Since we assume the devices are battery-driven, the objective is to minimize the power consumption as much as possible provided that the received SINR of each device is kept beyond an acceptable level so that the reliability can be guaranteed. We derive the power control algorithm function and prove the convergence of this iteration algorithm and the unique existence of Nash equilibrium as well. The simulation results show that under the same constraints of maximum power consumption and minimum acceptable SINR, the proposed algorithm outperforms the conventional algorithms in terms of power consumption and power efficiency.

  • Game-Theory-Based Distributed Power Splitting for Future Wireless Powered MTC Networks

    Kang Kang, Rong Ye, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEEE ACCESS   5   20124 - 20134  2017

     View Summary

    This paper studies the emerging wireless power transfer for machine type communication (MTC) network, where one hybrid access point (AP) with constant power supply communicates with a set of users (i.e., wearable devices and sensors) without power supply. The information and energy are transferred simultaneously in downlink direction. For MTC networks, most devices only receive several bits control data from AP in downlink transmission. So it is possible to utilize part of the received power to execute energy harvesting provided that the transmission reliability is guaranteed. Since we assume that all devices are without power supply or battery, the power of uplink transmission is entirely from energy harvesting. After converting electromagnetic wave to electricity, the devices are able to transmit their measured and collected data in uplink. Based on these considerations, a non-cooperative game model is formulated and a utility function involving both downlink decoding signal to noise ratio (SNR) and uplink throughput is established. The existence of Nash equilibrium (NE) in the formulated game model is proved. The uniqueness of NE is discussed and the expected NE is selected based on fairness equilibrium selection mechanism. The optimal splitting ratio within the feasible set, which maximizes the utility function, is obtained by an iterative function derived from this utility function. The numerical results show that in addition to ensuring the downlink decoding SNR and maximizing uplink throughput of an individual device, our proposed algorithm outperforms the conventional algorithm in terms of system performance.

    DOI

    Scopus

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  • Partnership and Data Forwarding Model for Data Acquisition in UAV-aided Sensor Networks

    Sotheara Say, Hikari Inata, Mohamad Erick Ernawan, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    2017 14TH IEEE ANNUAL CONSUMER COMMUNICATIONS & NETWORKING CONFERENCE (CCNC)     933 - 938  2017

     View Summary

    This paper explores a cooperative partnership and data forwarding model in wireless sensor networks using unmanned aerial vehicle (UAV) with the goal of enhancing the data collection efforts. A UAV-based data acquisition architecture is presented to suppress the limitations of the traditional wireless sensor network. For this, we introduce a flexible and fast approach to collect data by taking into consideration the mobility of the mobile sink (UAV) and sensor nodes in the network. In other words, leveraging the mobility of the UAV and the location of sensor nodes, we adopt a novel frame selection technique that classifies sensor nodes into different frames. Then we present a cooperative partnership model that allows sensor nodes in the network to individually pair with their peers and thus transmitting data simultaneously. We also aim to alleviate the packet loss originated from certain sensor nodes located in the rear edge-side of the UAV's coverage area. This situation happens when the UAV is moving in the forward direction while collecting data. Thus, to alleviate these packet losses while guaranteeing a higher success rate of packet reception ratio, we propose a novel data forwarding scheme to closely integrate with the aforementioned partnership model. We conduct simulations to verify our proposed framework, and results show huge performance gain is obtained over the traditional data collection technique.

  • Adjustable Energy Consumption Access Scheme for Satellite Cluster Networks

    Lilian del Consuelo Hernandez Ruiz Gaytan, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEICE TRANSACTIONS ON COMMUNICATIONS   E98B ( 5 ) 949 - 961  2015.05

     View Summary

    Satellite clusters have been satisfactorily implemented in a number of applications, such as positioning and sensor networks, with the purpose of improving communication system capabilities. However, because the use of clusters requires good management of the resources, those solutions imply new challenges for communication systems. This paper focuses on improving the data management between network elements by considering a network formed by satellite clusters. Satellite clusters work in cooperation to provide real-time and non-real-time services in different footprint areas. This study proposes the adjustable energy consumption access scheme (AECS) as one possible solution response to particular necessities of communication and at the same time, as a way of decreasing the system energy consumption. Energy consumption is a key issue that concerns green network operations and it is directly linked to the cooperation and coordination between network elements. On the other hand, we support the implementation of Optical Inter-Satellite Links (OISL) for communication between cluster elements. The analysis involves the study of energy consumption, transmission delay, specific link margins, bit error rate (BER) and QoS.

    DOI

    Scopus

  • Dynamic Scheduling for High Throughput Satellites Employing Priority Code Scheme

    Lilian Del Consuelo Hernandez Ruiz Gaytan, Zhenni Pan, Jiang Liu, Shigeru Shimamoto

    IEEE ACCESS   3   2044 - 2054  2015

     View Summary

    Based on the use of multi-beams, high throughput satellites (HTSs) provide high data rates to a large number of users. In this context, the distribution of frequency resources among multi-beams plays an important role. This is because unsuitable distributions might cause the wastage or the starvation of frequencies and bring about low throughput rates. This paper proposes a solution to mitigate the unsuitable allocations of frequency resources in an HTS. The solution is the priority code scheme (PCS), which seeks to respond to users' demands by dynamically scheduling frequency resources for precise satellite footprint areas. The key is to assign a priority code and an efficiency indicator to every multi-beam deployed on the system. The PCS algorithm involves the association of the efficiency indicator with the bandwidth utilization per beam to detect and correct arbitrary bandwidth allocations among the beams. Due to the PCS's cyclical repetition of its algorithm, the concurrence time of the scheme and the tardiness of the algorithm form part of the evaluation of the PCS. Furthermore, we support the implementation of the frequency-reuse process to enhance the exploitation of frequency resources. To evaluate the PCS performance, the analysis delves into the study of the bandwidth utilization, the interference among beams, the concurrence time, and the algorithm tardiness.

    DOI

    Scopus

    14
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  • Cooperative Access among UEs in Cellular Networks

    Megumi Saito, Li Xiwen, Zhenni Pan, Liu Jiang, Shigeru Shimamoto

    PROCEEDINGS OF THE 2015 INTERNATIONAL CONFERENCE ON COLLABORATION TECHNOLOGIES AND SYSTEMS     434 - 440  2015

     View Summary

    This paper proposes the Piggyback schemes between each User Equipment (UE) in cellular networks. This scheme is able to reduce a communication traffic volume of base station by each UE cooperates with other one. Therefore, it can make a smaller load in base station. Each UE establishes an independent connection and communication in current mobile network. When a UE accesses a base station, the UE receive data from other UEs nearby by device-to-device communication and the UE sends its own uplink data with the received data in this proposed method. We name the method a "Piggyback scheme". Here we introduce two methods; one is "real-time active calling based piggyback scheme". The calling UE receives uplink data from other UEs and the UE sends the data in free white space of its own real-time active call channel while using call function in this scheme. The second one is "Data aggregation piggyback scheme". In this scheme, when the UE sends its own uplink data to base station, the UE informs that it can piggyback execute for nearby UEs, and the UE receives data from the nearby UEs. And the UE sends data that includes its own and other's data. And piggyback request UEs use broadcast scheme in searching piggyback execution UE and it choice the best condition piggyback execution UE every time with plural evaluation criteria. In this paper, we confirm that performances of the proposed schemes have an effect on the load reduction of cellular network as it has been shown in the simulations.

  • Neuron Control-Based Power Adjustment Scheme for Sleep Two-tier Cellular Networks

    Zhenni Pan, Megumi Saitou, Jiang Liu, Shigeru Shimamoto

    2014 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC)     3201 - 3206  2014

     View Summary

    This paper proposes a self-optimizing based energy efficient scheme with a dynamic coverage expansion of femtocells in the macro-femto two-tier networks. High SINR and low power consumption can be benefited by coordinating downlink cross tier interference and intra-interference with a neuron control based adaptive power adjustment when sleep mode is involved in the macro base station (MBS). Moreover, by allowing open access in the hybrid femtocells, more near-indoor macro user equipments (MUEs), especially located around the edge of the macrocell can be served by indoor femto access point (FAP), which results in MBS having more of a probability to maintain sleep mode when the traffic is low. Many related performances are evaluated with a comparison of utility-based power control (UBPC) scheme, the energy impact of both MBS and FAP can be largely improved with optimal transmit power, which means the sleep mode technology can be enhanced, as shown in the simulation.

  • Impact of Light Reflection on Indoor Wireless Optical CDMA Systems

    Jiang Liu, Zhenni Pan, Wasinee Noonpakdee, Shigeru Shimamoto

    JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING   4 ( 12 ) 989 - 996  2012.12

     View Summary

    We present a study on evaluating the effects of multipath dispersion on indoor optical code division multiple access (CDMA) systems over optical wireless communication. The indoor propagation channel model which takes multiple reflecting surfaces into account is addressed. Theoretical analysis of the pulse response of direct light and reflected light is given. The bit error rate (BER) of this system is analyzed considering reflected light, background light, avalanche photo-diode noise, thermal noise, and multi-user interference. The results prove that the BER of the system is influenced by reflected light and that the effect of reflected light is related to room size and receiver position. With an increase in the number of users, the effect of reflected light becomes stronger and is a significant source of inter-symbol interference. It becomes clear that when optical CDMA is used in an indoor optical wireless system, the effect of reflected light is a key issue to be considered.

    DOI

    Scopus

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  • Impact of light reflection on indoor wireless optical CDMA systems

    Jiang Liu, Zhenni Pan, Wasinee Noonpakdee, Shigeru Shimamoto

    Journal of Optical Communications and Networking   4 ( 12 ) 989 - 996  2012

     View Summary

    We present a study on evaluating the effects of multipath dispersion on indoor optical code division multiple access (CDMA) systems over optical wireless communication. The indoor propagation channel model which takes multiple reflecting surfaces into account is addressed. Theoretical analysis of the pulse response of direct light and reflected light is given. The bit error rate (BER) of this system is analyzed considering reflected light, background light, avalanche photo-diode noise, thermal noise, and multi-user interference. The results prove that the BER of the system is influenced by reflected light and that the effect of reflected light is related to room size and receiver position. With an increase in the number of users, the effect of reflected light becomes stronger and is a significant source of inter-symbol interference. It becomes clear that when optical CDMA is used in an indoor optical wireless system, the effect of reflected light is a key issue to be considered. © 2009-2012 OSA.

    DOI

    Scopus

    10
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  • Performance analysis of image sensor communication over free space optical channel

    Jiang Liu, Zhenni Pan, Shigeru Shimamoto

    IST 2012 - 2012 IEEE International Conference on Imaging Systems and Techniques, Proceedings     627 - 632  2012

     View Summary

    This paper presents a free space visible light communication (VLC) system using an image sensor as a receiver to acquire position related timely information. Since the atmospheric turbulence affects the communication quality, the analysis of atmospheric turbulence is very important for designing a practical communication system. In this paper, the atmospheric turbulence channel is analyzed. The method of characterizing and quantifying the influence of atmospheric effect to image sensor communication is presented. The noise model of the system using CMOS image sensor as a receiver is given. Furthermore, the bit error probability of the system using OOK modulation considering atmospheric turbulence is studied. © 2012 IEEE.

    DOI

    Scopus

    4
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  • Experiment on space and time division multiple access scheme over free space optical communication

    Jiang Liu, Jin Sando, Shigeru Shimamoto, Chiemi Fujikawa, Kashiko Kodate

    IEEE Transactions on Consumer Electronics   57 ( 4 ) 1571 - 1578  2011.11

     View Summary

    Developments in outdoor free space optical (FSO) communication between buildings using rooftopmounted units are limited by Point-to-Point wireless links. We propose a space and time division multiple access scheme to perform Point-to-Multi-Point communication employing reflectors. A single reflector controlled by a stepping motor and an array of fixed reflectors are used. The reflection characteristics of the reflector are measured. The relationship characteristics between the static angle error of the stepping motor, the beam fluctuation, and the communication distance are demonstrated. The received optical powers are compared on using one or two reflectors while considering the angle of incidence at the surface of the reflector. Moreover, the received power, the bit error rate and the throughput of the experiment system are measured. In addition, the throughput characteristics of the proposal scheme are made clear by experiments. The result of the experiment shows that the new scheme can provide a low-cost and efficient method for Point-to-Multi-Point FSO communication 1. © 2006 IEEE.

    DOI

    Scopus

    9
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  • Performance Evaluation of Multi Hop Relay Network for Oceanic Air Traffic Control Communication

    HO Dac-Tu, PARK Jingyu, SHIMAMOTO Shigeru, KITAORI Jun

    IEICE Trans. Commun.   94 ( 1 ) 86 - 96  2011.01

     View Summary

    This paper proposes a new kind of communication system for air traffic control over the oceans; it is particularly effective at handling high air traffic loads due to many oceanic flights. In this system, each aircraft position report is sent to its relevant ground station by forwardly relaying them via a multi hop ad-hoc network that is formed by the aircraft between this aircraft and the ground station. In addition, an effective multiple access scheme with optimal values is also proposed. This scheme enables the various aircraft involved in relaying the signal to operate autonomously in a flight-route airspace. Furthermore, two useful schemes are proposed for efficient timeslot reuse and timeslot assignment in cases of low aircraft densities: the position aided timeslot reuse (PATR) and distance based timeslot assignment (DBTA), respectively. Finally, another scheme is proposed to improve the achievable relayed packet rate under low aircraft densities, which is called interference-based node selection (IB-NS). In all, the proposed system combined with those three schemes show the availability to utilize this system for air traffic control communications, specifically on high traffic ocean routes.

    DOI CiNii

    Scopus

    5
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  • Long distance optical wireless network employing multiple access scheme

    Jiang Liu, Jin Sando, Wei Li, Hiroshi Takano, Shigeru Shimamoto, Chiemi Fujikawa, Kashiko Kodate

    GLOBECOM - IEEE Global Telecommunications Conference     2258 - 2262  2007

     View Summary

    There has been many developments in long distance optical wireless communication between buildings using rooftop-mounted units over Point-to-Point wireless links. We propose an Angle Division/Time Division Multiple Access scheme to perform Point-to-Multi-Point communication employing reflectors. A single reflector controlled by a stepping motor and an array of fixed reflectors were used. The width of the beam of the infrared rays is measured and the relationship between the width and the stepping angle deviation of the motor are demonstrated. Moreover, the received power, the bit error rate, and throughput of the proposal scheme are measured. The angle of the reflector and the reflection characteristics when using one or two reflectors were compared. In addition, the throughput characteristics of the proposal scheme were made clear by experiments.

    DOI

    Scopus

    3
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  • Proposal and evaluation of 8-ary elliptical phase shift keying

    CY Song, S Shimamoto

    ICC 2005: IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-5     598 - 602  2005

     View Summary

    Some modulation schemes with the general name of. Elliptical Modulation Schemes, have been proposed and generally evaluated through computer simulations in our previous works, namely are Eccentricity Shift Keying (ESK), Inclination Angle Shift Keying (IASK) and Elliptical Phase Shift Keying (EPSK). This paper aimed to propose and evaluate 8-ary Elliptical Phase Shift Keying (8-EPSK), a new modulation scheme with 3-bit information transmission capability. In the paper, 8-EPSK was defined mathematically at first; it was then evaluated mathematically and by computer simulation in terms of BEP, along with comparison to 8PSK. Both analysis results and simulation results showed that 8-EPSK outperforms 8PSK.

  • 中継局選択型マルチホップモバイル通信に関する研究

    NASU Yukiko, SHIMAMOTO Shigeru

    電子情報通信学会   vol.J88-B ( 1 ) 234 - 224  2005.01

    CiNii

  • 光無線通信を用いた車両内データアクセス方式の提案及び光伝搬モデルに関する考察

    TAKANO Hiroshi, FUTATSUGI Yasunori, SHIMAMOTO Shigeru, SEKI Kiyotaka

    電子情報通信学会   Vol.J87-B ( 7 ) 950 - 962  2004.07

    CiNii

  • A study of optical wireless mobile communications with movable cells employing cycle emissions

    H Takano, S Shimamoto

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS   87 ( 10 ) 45 - 57  2004  [Refereed]

     View Summary

    This paper considers the application of optical wireless Communications to mobile communications. We consider an optical mobile communications system using cycle emission cells and allowing a reduction of the shadowing effect, which is a problem in optical wireless communications. The proposed system uses multiple transmitters with cycle emissions (DTCE). By varying the number of transmitters, the error rate performance is compared via computer simulation. It is anticipated in particular that when the proposed method is applied to mobile communications, multiple transmitters will be placed in the service area, and the distance between the transmitters and the synchronization among the transmitters will greatly affect the error rate performance. The performance is calculated by varying these parameters via computer simulation, and the results are evaluated. Furthermore, the result is compared to other models which have been proposed in order to reduce the shadowing effect, and the effectiveness of the DTCE system regarding optical wireless mobile communications is demonstrated. (C) 2004 Wiley Periodicals, Inc.

  • Analysis and Practical Countermeasures for Adjacent Channel Interferences of an Airbone VHF Communications System

    TSUDA Yoshio, SHIMANOTO SHigeru

    IEICE Transactions on Communications   VOl,J86-B, No.7 ( 7 ) 1126 - 1138  2003.07

    CiNii

  • 航空機搭載VHF通信システムの干渉障害の検証及び対策

    TSUDA Yoshio, SHIMANOTO SHigeru

    電子情報通信学会論文誌B   Vol.J86-B, No.7 ( 7 ) 1126 - 1138  2003.07

    CiNii

  • 巡回発行セルを用いた光移動体通信に関する研究

    TAKANO Hiroshi, SHIMAMOTO Shigeru

    電子情報通信学会論文誌B   Vol.J86-B, No.4 ( 4 ) 659 - 670  2003.04

    CiNii

  • Poposals of New Modulation Schemes employing Elliptical Cirlce

    IEEE WCNC2003   TS-8-004  2003.03

  • A variable gain amplifier using a photo coupler for a low frequency IF amplifier stage

    Y Tsuda, S Shimamoto

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E86A ( 2 ) 280 - 287  2003.02  [Refereed]

     View Summary

    This paper presents a practical implementation scheme of the variable gain amplifier (VGA) using a Cds photo coupler (Cds PC) as a variable resister at the feedback loop. The fundamental design policies of IF amplifier stage in super-heterodyne receiver were described. We demonstrated the VGA's experimental results. The results indicated the excellent IIP3 of +25 dBm achieved by a gain of 15 dB, and the reasonable thermal stability and variable gain range. Third-order intermodulation distortion (IMD3) comparison between the proposed VGA and conventional PIN diode attenuation type VGA was evaluated and the result indicated that the proposed VGA surpassed the PIN VGA. The proposed VGA was practically fabricated in 455 kHz IF amplifier stage for an airborne VHF communication receiver in order to improve the large signal handling capability to eliminate numerous interferences resulting from the collocated airborne VHF communication systems on the aircraft.

  • A variable gain amplifier using a photo coupler for a low frequency IF amplifier stage

    Y Tsuda, S Shimamoto

    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES   E86A ( 2 ) 280 - 287  2003.02  [Refereed]

     View Summary

    This paper presents a practical implementation scheme of the variable gain amplifier (VGA) using a Cds photo coupler (Cds PC) as a variable resister at the feedback loop. The fundamental design policies of IF amplifier stage in super-heterodyne receiver were described. We demonstrated the VGA's experimental results. The results indicated the excellent IIP3 of +25 dBm achieved by a gain of 15 dB, and the reasonable thermal stability and variable gain range. Third-order intermodulation distortion (IMD3) comparison between the proposed VGA and conventional PIN diode attenuation type VGA was evaluated and the result indicated that the proposed VGA surpassed the PIN VGA. The proposed VGA was practically fabricated in 455 kHz IF amplifier stage for an airborne VHF communication receiver in order to improve the large signal handling capability to eliminate numerous interferences resulting from the collocated airborne VHF communication systems on the aircraft.

  • デジタル放送教科書

    IDG    2003.01

  • Proposals of new modulation schemes employing elliptical circle

    S Shimamoto

    WCNC 2003: IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE RECORD, VOLS 1-3   TS-8-004   223 - 226  2003  [Refereed]

     View Summary

    Most of current wireless communications take sinusoidal waveforms derived from circles. In this paper, new modulation schemes using elliptical circles, in stead of usual circles, are proposed. Several schemes proposed in this paper can be described as "Elliptical Modulation" which modulates signals by varying the geometrical characteristics of ellipses. The elliptical modulation method involves variables such as eccentricity, rotation, revolution frequencies and offset inclination angles. In this paper, several schemes. based upon elliptical modulation have proposed. A performance evaluation of the proposed scheme is shown as well. The proposed schemes seem to open up a new research area of telecommunication field in the future.

  • Proposals of new modulation schemes employing elliptical circle

    Shigeru Shimamoto

    IEEE Wireless Communications and Networking Conference, WCNC   1   223 - 226  2003

     View Summary

    Most of current wireless communications take sinusoidal waveforms derived from circles. In this paper, new modulation schemes using elliptical circles, instead of usual circles, are proposed. Several schemes proposed in this paper can be described as "elliptical modulation" which modulates the signals by varying the geometrical characteristics of ellipses. The elliptical modulation method involves variables such as eccentricity, rotation, revolution frequencies and offset inclination angles. In this paper, several schemes based upon elliptical modulation have been proposed. A performance evaluation of the proposed scheme is shown as well. The proposed schemes seem to open up a new research area of telecommunication field in the future.

    DOI

    Scopus

    5
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  • 洋上航空路アドホックネットワークの提案

    TSUDA Yoshio, SONG Chunyi, SHIMAMOTO Shigeru, MATSUSHITA Seiji, KITAORI Jun, KATO Satoshi

    電子情報通信学会論文誌   Vol.ZJ85-B, No12 ( 12 ) 2054 - 2062  2002.12  [Refereed]

    CiNii

  • A proposal of an Ad-Hoc Network on Oceanic Flight Route

    TSUDA Yoshio, SONG Chunyi, SHIMAMOTO Shigeru, MATSUSHITA Seiji, KITAORI Jun, KATO Satoshi

    IEICE Transactions on Communications   Vol.J85-B, No.12 ( 12 ) 2054 - 2062  2002.12

    CiNii

  • 洋上航空路アドホックネットワークの提案

    TSUDA Yoshio, SONG Chunyi, SHIMAMOTO Shigeru, MATSUSHITA Seiji, KITAORI Jun, KATO Satoshi

    電子情報通信学会論文誌   Vol.ZJ85-B, No12 ( 12 ) 2054 - 2062  2002.12

    CiNii

  • 仰角別電波伝搬特性を考慮した成層圏飛翔体通信に関する研究

    ISHIJIMA Yoshitomo, SHIMAMOTO Shigeru

    電子情報通信学会 無線通信システム研究会   RCS2001-133 ( 370 ) 21 - 28  2001.10

     View Summary

    The important elements of communications between high altitude base station, such as stratospheric aircraft and land mobile station communication, are mutual distance and relative elevation angle. Due to the nature of reflection and incidence angles, direct propagated wave is not interfered as mush by scattering wave at high elevation angles, while it is readily interfereed at low elevation angles. This implies that propagation characteristics must be different for high and low elevation angles. The effect of changing elevation angles on multipath radio propagation was experimentally in vestigated by using trial aircraft survey method, to examine under various conditions was performed. The data obtained from experiment measurements was used for simulations of propagation characteristics conditioned at different elevation angles and in different cities.

    CiNii

  • 可変長フレームを用いたアクセス制御方式に関する研究

    電子情報通信学会 ソサイエティ大会   B-7-16  2001.09

  • 多段位相変位を用いた位相ダイバーシチ方式に関する考察

    電子情報通信学会 ソサイエティ大会   B-8-25  2001.09

  • A Study of New Modulation Dimension Employing Geomrtrical Characteristics of the Ellips

    LEE Ileana

    電子情報通信学会 ソサイエティ大会   B-8-26  2001.09

    CiNii

  • 都市規模に基づく仰角別見通し状況に関する研究

    KOBAYASHI Hironori, ISHIJIMA Yoshitomo, SHIMAMOTO Shigeru

    電子情報通信学会総合大会   SB-2-6   759 - 760  2001.03

    CiNii

  • 位相ダイバーシチを用いた多重アクセス方式に関する考察

    電子情報通信学会総合大会   B-8-21  2001.03

  • 多偏波適応型ワイヤレスアクセス方式に関する考察

    電子情報通信学会総合大会   B-5-324  2001.03

  • 電車車両内における光無線通信の適用に関する研究

    IWASAKI Daichi, SHIMAMOTO Shigeru

    電子情報通信学会総合大会   Bー5ー306   704 - 704  2001.03

    CiNii

  • 成層圏飛翔体を用いた移動体通信システムにおける通信方式の提案及びその性能評価

    電子情報通信学会論文誌   B Vol.J83-B, No.5,  2000.05

  • 仰角別電波伝搬特性の測定

    KOBAYASHI Hironori, ISHIJIMA Yoshitomo, SHIMAMOTO Shigeru

    電子情報通信学会総合大会   B-3-39   295 - 295  2000.03

    CiNii

  • 成層圏飛翔体を用いた移動体通信システムにおける通信方式の提案及びその評価

    電子情報通信学会論文誌   J83-B/5,666-676  2000

  • 低軌道衛星移動体におけるシャドウイング状況を考慮したデータ転送方式の検討

    電子情報通信学会衛星通信研究会   SAT99-95 ( 367 ) 31 - 36  1999.10

    CiNii

  • 遠隔医療に関する研究

    小型衛星研究会   E-F-07  1999.10

  • 巡回発行セルを用いた光移動体通信に関する一考察

    電子情報通信学会ソサエティイ大会   Bー5ー157  1999.09

    CiNii

  • 電子情報通信用語辞典

    コロナ社    1999.06

  • Performance evaluations of communication systems employing stratospheric aircrafts and LEO satellites

    S Shimamoto, T Mikoshiba, S Takakusagi, M Hayashi, H Shiba

    IEICE TRANSACTIONS ON COMMUNICATIONS   E81B ( 12 ) 2343 - 2350  1998.12  [Refereed]

     View Summary

    In recent years, several global network systems using non-stationary satellites have been proposed. Some of them are announced to start services within years. We also have several experimental systems with stratospheric aircrafts. In the future, the radio communication system using stratospheric aircrafts will be one of the promising media for personal communications. The question of how to establish the optimal communication under such circumstance seems to be still open. In this paper, performance evaluations of wireless communication systems using LEO satellites and stratospheric aircrafts are proposed. We will show some proper communication parameters to improve competence of mobile communication in the such systems as well.

  • 送信電力制御を用いた衛星通信網制御に関する研究

    SHIMAMOTO Shigeru, KUBOTA Hideki, KUWABARA Hiromasa, ONAZATO Yoshikuni

    電子情報通信学会論文誌   Vol.81-B-II, No.5 ( 5 ) 409 - 418  1998.05

    CiNii

  • 捕捉効果を利用した可変長データ転送方式

    KIKUCHI Keiko, SHIMAMOTO Shigeru

    電子情報通信学会論文誌   Vol.81-B-I, No.3 ( 3 ) 152 - 161  1998.03

    CiNii

  • 捕捉効果を利用した可変長データ転送方式

    KIKUCHI Keiko, SHIMAMOTO Shigeru

    電子情報通信学会論文誌   Vol.81-B-I, No.3 ( 3 ) 152 - 161  1998.03

    CiNii

  • 送信電力制御を用いた衛星通信網制御に関する研究

    SHIMAMOTO Shigeru, KUBOTA Hideki, KUWABARA Hiromasa, ONAZATO Yoshikuni

    電子情報通信学会論文誌B-II   J.81-B-II/5,409-418 ( 5 ) 409 - 418  1998

    CiNii

  • 大学間共同衛星通信実験

    電子情報通信学会誌   80/5,435-456 ( 5 ) 435 - 456  1997

    CiNii

  • トラヒック集中を考慮した完全結合型網におけるネットワークの安定性

    KANAZAWA Ami, SHIMAMOTO Shigeru, ONOZATO Yoshikuni, TERUYA Ken

    電子情報通信学会論文誌B-I   J79-B-I/6,415-423 ( 6 ) 415 - 423  1996

    CiNii

  • 捕捉効果を用いた割当ウンドウアクセス方式

    SAITO Miki, SHIMAMOTO Shigeru, KUDOU Hikaru, ONOZATO Yoshikuni

    電子情報通信学会論文誌   J79-B-I/3,90-97 ( 3 ) 90 - 97  1996

    CiNii

  • 通信衛星を用いた医学画像通信の検討〜骨シンチグラムをモデルとして〜

    核医学   32/10,1073-1077  1995

  • Assigned power level and assigned slot‐based multiple‐access scheme by capture effect

    Shigeru Shimamoto, Yoshikuni Onozato, Yoshimi Teshigawara

    Electronics and Communications in Japan (Part I: Communications)   76 ( 11 ) 48 - 58  1993

     View Summary

    The TDMA scheme, a typical multiple‐access scheme, can provide secure transmission
    but its efficiency is poor under low traffic conditions. By contrast, the random access scheme, represented by the ALOHA scheme, has a small‐delay characteristic under low traffic conditions but a stability problem under heavy traffic conditions. This paper presents a new multiple‐access scheme in which each station is assigned a slot in every frame and stations are assigned to a slot at different power levels to obtain the capture effect. Therefore, the proposed scheme can adapt itself under various traffic conditions with channel status monitoring based control. Different models of capture effect are proposed, and the performance of the models is analyzed both by theory and by computer simulation. Copyright © 1993 Wiley Periodicals, Inc., A Wiley Company

    DOI

    Scopus

  • 小型周回衛星を用いた情報ネットワークシステムの一検討

    電子情報通信学会   B-II/J76-B-II,773-774  1993

  • スロット内分割使用可能なスロット付きアロハ方式

    電子情報通信学会   B-I/J76-B-I,129-137  1993

  • 捕そく効果を利用した送出レベルおよび送出スロット割当て方式

    SHIMAMOTO Shigeru, ONOZATO Yoshikuni, TESHIGAWARA Yoshimi

    電子情報通信学会   J75-B-I/12,773-781 ( 12 ) 773 - 781  1992

    CiNii

  • Combined ALOHA/TDMA Access Scheme with TDMA Window Control

    INADA T.

    IEICE   J73-B-II/8,444-448 ( 8 ) p444 - 448  1990

    CiNii

  • TDMAウィンドウ制御を用いたアロハ/TDMA複合アクセス方式

    INADA T.

    電子情報通信学会   J73-B-II/8,444-448 ( 8 ) p444 - 448  1990

    CiNii

  • Evaluation of Channel Partition Methods for Combined ALOHA/Reseruation Access Schemes

    IEICE   J70-B/11,1360-1366  1987

  • アロハ・予約複合アクセス方式における容量配分方式の評価

    電子情報通信学会   J70-B/11,1360-1366 ( 11 ) p1360 - 1366  1987

    CiNii

▼display all

Books and Other Publications

  • 電子情報通信用語辞典

    コロナ社  1999

Research Projects

  • Proposal and Evaluation of Ultra Reliable Low Latency Communication

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2019.04
    -
    2022.03
     

    Shimamoto Shigeru

     View Summary

    The research was mainly concerned with the proposal and evaluation of wireless communication within robots. It was found that the propagation of radio waves in robot arms and legs depends greatly on the frequency, and that there are some frequencies that are very difficult to propagate. We constructed an environment that simulates the actual robot as much as possible and succeeded in acquiring the propagation in a more realistic environment. The research was accepted for publication in IEEE journals and international conferences, received the Best Presentation Award at international conferences, and was highly evaluated both domestically and internationally.

  • 世界最高水準のモバイルICT環境を実現する次世代情報通信基盤と応用実証

    Project Year :

    2015.04
    -
    2019.03
     

     View Summary

    本申請の研究開発項目として以下を設定している。基盤技術として、(1) 無線通信履歴の取得、(2) 無線通信履歴を活用した通信品質予測、(3) 品質予測に基づく適応配信制御と最適経路探索。拡張技術として、(4) クラウド拡張、セキュリティ、センサー活用、新無線技術、QoE評価、(5) アプリケーションの具体化とプロトタイプ実装。(1)では、初年度に開発したスマートフォンアプリを使用し、大学周辺の無線通信品質計測を進めている。この時、移動手段や時間情報による場合分けも進めている。(2)では、初年度から継続して隠れマルコフモデルと線形予測分析を併用したスループット予測の検討を進めており、国際学会発表を行うと共に、論文誌投稿を準備している。(3)では、通信品質履歴を活用し、スループットを最大化、もしくは消費電力を最小化する移動経路を提示し、実機実験によって有効性を実証し、国際学会で成果発表を行った。(4)でば、クラウド拡張として、研究室内にパーソナルクラウド、学外に商用クラウドを配し、携帯端末情報をエッジ処理する階層化クラウド環境を整備した。セキュリティに関しては、マルウェア対策のためのトラヒック分析に関する成果発表を行った。センサー活用に関しては、可視光カメラ、赤外線カメラ、測距センサーなどを配した実験環境を構築し、イベント検知に基づく適応配信制御に関する成果発表を行った。無線技術に関しては、5Gを想定した実験環境の情報収集と整備を開始した。QoE評価に関しては、新指標の構築を目指した注視点計測等の成果発表を行った。(5)では、高効率・省電力映像配信アプリケーション、家庭内の8K映像再配信、各種IoTデバイスを用いたセンサーアプリケーション、などのプロトタイプ実装を進めた。これらに加え、次世代ネットワークや無線LANの効率的な制御技術に関する招待講演も行った。本研究課題はおおむね順調に進展している。また、昨年度は研究費の前倒し申請を行い、研究開発の加速に役立てた。(1)では、初年度に開発したスマートフォンアプリを活用し、大学周辺の無線通信品質の計測を進めている。また、アプリ拡張として、ダウンロードに加えてアップロード時の省電力化を図る工夫を加えている。(2)では、現状の隠れマルコフモデルと線形予測分析によるアプローチに加え、機械学習を活用した方式検討の準備を進めている。(3)では、実機実験評価として提案方式の有効性を確認し、論文誌投稿の準備を開始した。(4)では、クラウド拡張では、OpenStackによるパーソナルクラウド構築をほぼ完了し、次年度以降の通信実験、ならびに応用実験の目途を付けた。セキュリティでは、研究成果の論文誌投稿の準備を進めている。センサー活用では、上記クラウド拡張と連携し、エッジコンピューティングも活用した効率的かつ柔軟な応用開発を目指している。無線技術は2020年の5G実用化を想定した実験準備を開始し、シミュレーション評価、実機評価実験の二面から準備を進めている。QoE評価に関しては、観測可能な変数(瞬断時間など)からのQoE推定式も活用した評価実験を進めている。(5)のアプリケーション開発では、各種のプロトタイプ実装と評価に加え、上記クラウド拡張とセンサー活用を統合した今後の新規なプロトタイプ実装の準備を進めている。(1)の通信履歴取得では、スマートフォンアプリの開発・改良を進め、試験的な公開を目指す。ユーザに不要なストレスを与えないインライン計測は昨年度からの継続課題であり、今後も継続する。(2)の通信品質予測では、国際学会の動向も踏まえ、深層学習の導入が緊急の課題であり、新規課題としての検討を進める。このとき、(4)のクラウド拡張を踏まえた深層学習の計算環境整備も課題になる。(3)の適応配信制御と最適経路探索に関しては、プロトタイプ実装も含めた評価として、基礎検討に関しては一通りの目途を付けた。今後は、規模の拡大や無線通信環境の動的な変化への対応など、実用的な課題検討にシフトする。(4)の拡張技術に関しては、まずクラウド拡張とセンサー活用を統合し、各種の通信実験と応用実験への拡張を図る。具体的には、SDN拡張やビッグデータ拡張が可能であり、必要に応じて拡張テーマを設定し、外部資金による新規の研究費申請も検討する。また、(1)の通信履歴取得とセンサー活用の統合も図り、通信履歴取得に加え、人間の行動分析等への拡張を図る。また、新無線技術は5Gへの対応を図り、4K/8K映像配信のシミュレータ・エミュレータ評価を開始し、今後の実機評価に向けた準備を進める。QoEに関しては、人間の知覚特性の計測と反映を継続すると共に、客観指標の活用によるプロトタイプ実装評価への適用を図る。(5)のアプリケーション開発に関しては、最終年度も想定し、各種のプロトタイプ実装を開始する

  • Disaster environment adaptive and energy saving never-die network to maximize connection rate satisfaction of a large number of users

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2014.04
    -
    2017.03
     

    Shiratori Norio

     View Summary

    In order to solve the two problems of "huge disaster" and "global warming", as a technology to maximize "connection rate satisfaction" of a large number of people (more than 1 million) who became unable to communicate at the time of a disaster, we proposed and established a fundamental technology of "Disaster Environment Adaptive and Energy Saving Never-die Network". Specifically, we studied and developed ICT technology that allows to grasp the disaster situation autonomously in the event of a disaster and allows multiple people to confirm their safety, while minimizing power consumption. The effectiveness was also shown from some prototype experiments

  • Sudies on Communication employing Ultra Sonic Signal

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2014.04
    -
    2017.03
     

    Shimamoto Shigeru

     View Summary

    WHO define affect of electricmagnetic fields to human body as 3b(out of 5) in 2011. So we must find out more safety media for near field communication. In this study, we have shown the possiblities of usage of ultrasonic communication for indoor applications and shown experimental equations for propagations and transmission rate. We conducted experiments changing symbol rates. The media is air and steel. The experimental distances are 30cm, 60cm, 120cm and 240cm. When symbol rate range is 200k-1000ksps in air, the change of EVM can be seen clearly by experimental distance and symbol rate. And then because the change of EVM in the experimental distance of30cm and 60cm is not large in symbol rate range of200k-1000ksps, the formula is found in the experimental distanceof 120cm and 240cm

  • Studies on Wide Area Network employing Unmanned Aerial Vehicle

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2011.04
    -
    2014.03
     

    SHIMAMOTO Shigeru

     View Summary

    In this study, is possible that the missing person search in the disaster area using not only the air picture but also sensor technology by using Unmanned Aerial Vehicle (UAV). UAV is generally used as a spy plane in the United States and China, but suggests a model to use as a search machine using the sensor technology in this main study. I aim the missing person position identification systems construction from the exchanges of a watch type transponder and the signal with UAV. We have introduced a novel approach implemented to leverage the performance of Medium Access Control for Wireless Sensor Networks and UAV. In fact, including the wristwatch type transponder antenna production evaluation, and also communicates quality evaluation transmission success rate in UAV-sensors, average transmission delay, bit error rate, and packet error rate

  • Study on Access Scheme and Application for Inter-Intra Body Communication

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2008
    -
    2010
     

    SHIMAMOTO Shigeru

     View Summary

    In this research, we examined identification of finger or palm. As for the finger identification scheme, we have succeeded to detect each finger by using received power difference and phase difference. As for the palm detecting, we have proposed palm typing scheme and palm writing scheme. We confirmed that our proposal can become practical use. Furthermore, we have succeeded to detect movements of arm and wrist in order to distinguish Jyanken

  • 楕円変調方式に基づく変調方式、アクセス方式に関する多角的な研究

    日本学術振興会  科学研究費助成事業

    Project Year :

    2005
    -
    2007
     

    嶋本 薫, QIAO Y, YANTAO Qiao, QIAO Yantao

     View Summary

    1 楕円変調方式に関する研究
    Rate2/3Trellis-Coded 8-ary Elliptical Phase Shift Keying Modulationというタイトルで国際的にも認知度が高く難関国際会議として知られるIEEE International Symposium on Wireless Communication Systems 2007(ISWCS'07)において採録、発表された上記の論文は、楕円変調方式を用いて8相の変調行う場合の具体的なデータ転送方式についてその手法、並びに性能評価を述べている。トレリス符号はBS放送等でも用いられる誤り特性の優れた手法であり、その組み合わせにより新変調方式の具体的なアプリケーション開発に向けた設計が確立された。オックスフォード大学を始めとする海外の研究者が多数本研究に興味を持っており、ISWCS'07のノルウエーでの発表もわざわざオックスフォードから聴講に来るぼどであった。それ以外にも海外からの問い合わせは多く、早稲田発のこの方式がYantao氏の努力で世界に広まりつつある
    2 符号化方式に関する研究
    A Study on Iterative ULS(Unequal Length Search)Syndrome Decoding for Product Codes無線通信分野では世界最高峰の難易度を誇るIEEE Wireless Communications and Networking Conference(WCNC2008)において採録され、発表される上記の研究はこれまでの研究の過程において派生した符号化方式に関するものであり、反復不均一長検索シンドロームに基づく復号方式(Iterative Unequal Length Search(ULS)syndrome decoding)は従来方式と比べた場合、処理負担の軽減が可能なうえに検出能力が高いという優れた特徴を備えている。

  • Studies On Wide Area Multi-Hop Network in HF BAND

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2005
    -
    2006
     

    SHIMAMOTO Shigeru

     View Summary

    We have studied and proposed HF Wide Area Multi-Hop Network in HF Band for emergency situation. It is possible for us to have communication over long distance with low cost in HF Band. It is also possible to have networks without any of infrastructures and Hub station. In this study, we proposed wide area multi-hop network employing HF long distance propagation based upon ionosphere layer reflection. We also proposed some access methods for such systems in terms of shift of transmitting timing and elevation angle control. We have examined the possibilities of elevation angle control using adaptive array system for HF band by some experiments. By using such schemes, we have achieved that our proposed schemes are useful in practical use especially for emergency situations

  • Multilateral Studies for Mobile Communications employing Optical Wireless Signal

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2001
    -
    2002
     

    SHIMAMOTO Shigeru

     View Summary

    We have proposed new access schemes which are harmless for human body and medical equipment using optical wireless communication. New access schemes of cyclic emission of optical mobile systems are proposed as well. I denote the results.1) We have proposed a new access scheme for the people in trains by using optical wireless communication which is harmless to the people who have pace maker.2) We have designed hardware components for the optical wireless systems with many kinds of optical emitter and receiver. We have succeeded to develop an experimental system which is useful to measure delay profile.3) We have measured reflection patterns of optical ray for stainless steel and mirror with respect to angles of incidence. As results, we observe high levels of reflections when we have high incident angles.4) Experiments of optical signal propagation inside train has been done by this works. We have measured many kinds of delay profiles in the real train. We observed the optical signal with 1.5ns delay as reflected signals. The strength of reflected signals are almost 20% of direct signal in case of stainless steel. On the other hand, almost 7.3% of direct signal strength has derived with window pan.5) Measurements of digital modulated signal have been done by this work in terms of affection by optical signal reflections by stainless steel and window pan.6) We have studied optical wireless communication applied to mobile communication. In this paper, we examine optical wireless mobile communication system with movable cells employing cycle emissions in order to reduce shadowing. We examine the case of changing the number of transmitters in this system by computer simulation. In case of this system applied to mobile communication, BER is influenced by difference of synchronization and distance among transmitters; this paper analyzes the performance based upon such parameters. We show this system is effective in optical wireless communication from result of comparing this system with other systems proposed before

  • Next Generation VHF Digital Link

    Project Year :

    2001
    -
     
     

  • Satellite Network System

    Project Year :

    2000
    -
     
     

  • Simultaneous Spread-Time and Spread-Spectrum Modulations with Software Radio Techniques

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    1999
    -
    2000
     

    OKA Ikuo, SHIMAMOTO Shigeru

     View Summary

    The research results on the project "Simultaneous Spread-Time and Spread-Spectrum Modulations with Software Radio Techniques" are summarized as follows.(1) The simultaneaous spread spectrum and spread time modulation system is developed. The modulation is obtained by the spread of spread spectrum FSK in time axis.(2) The waveform, spectrum, and error probability of the developed system are given by the sumulations. The capacity of the system is derived theoretically, and it is shown to be the same as those of spread time PPM and spread spectrum FSK.(3) In the simultaneous spread spectrum and spread time modulation system, the performance depends on the assignment method of channel resource, which is the number of independent dimensions employed in the bandwidth-time space. The assinment method is developed for an adaptive operation to the channel condition.(4) The transmitter function of the simultaneous spread spectrum and spread time modulation system is included in the program of DSP, which generates the waveform of the system.(5) As the error correction of the simultaneous spread spectrum and spread time modulation system, the separate coding with iterative decoding is introduced. The corelation information of the received PPM time slot is effectively employed at the iterative decoding, and the coding gain is shown to be almost the same as full states decoding. The turbo coding is also applied to the system for further improvement.(6) For the efficient use of frequency spectrum, the new modulation is developed. The modulated signal is sent after the cut of discrete spectrum, and the spectrum is recovered in the receiver. The error probability for 1/2, 1/4, and 1/8 spectrum PPM is demonstrated for the example

  • FWA Access Scheme

    Project Year :

    1999
    -
     
     

  • 可変転送レート機能を用いた多元接続方式の構築に関する多角的研究

    日本学術振興会  科学研究費助成事業

    Project Year :

    1994
     
     
     

    嶋本 薫

  • A STUDY ON GROUP WORKS THROUGH GLOBAL COMMUNICATION NETWORKS

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    1992
    -
    1993
     

    ONOZATO Yoshikuni, SHIMAMOTO Shigeru

     View Summary

    1) Architecture of a global mesage network employing low earth-orbiting satellites :We have presented a concept of a global message network, catering to low density traffic from user terminals, using a constellation of low-altitude astellites. Under low traffic, performance measures are estimated.2) Communication structure of group works through global communication networks :2.1) We have proposed a new architecture of a copy network which employs the principle of recursive generation of copy cells.2.2) We have proposed a new algorithm, called PCRA, which can be implemented in a Q-channel connection request environment, where Q>3.3) Modeling and analysis of group works through a global message network :We have presented a global message network employing low earth-orbiting satellites to collect information from finite users in a restricted area. We have shown useful transmission rate to get maximum successful transmissions within a period

  • 高性能多元接続方式の構築に関する多角的研究

     View Summary

    本研究では実衛星を用いた実験を元に、様々な高性能多元接続方式の構築を行った。その概要を以下に示す。(1)実衛星を用いた捕捉効果実験本研究では実衛星(JC-SAT1)を用い、複数キャリアを同一周波数で、異なる電力レベルによるアクセスを行ない、捕捉効果の存在を確認した。実験の結果、実用衛星並びに地球局設備を用い、2レベルの場合は2局間では約5dB、3局間では約9dBで、それぞれ捕捉効果の得られることが明らかになった。更に、3レベルを用いた捕捉も実現可能であることを定量的に示した。捕捉効果という新たななる次元での可能性を示したものとして、高い評価を受けた。(2)捕捉効果を用いた高性能多元接続方式の構築実験により得られた、捕捉効果を用いた多元接続方式としてFAWAC(Fixed Assingment based Window Aucsess)を考案し、その理論解析を行なった。FAWACは低電力で即時送信を行ない、割り当て送信を高電力で行なうもので、低負荷から高負荷までその適用範囲が広く、捕捉効果により遅延特性の優れた方式である。解析では各局が異なったトラヒックを持つ場合など、多様で不均一な環境を想定しその特性を評価した。また、発生データ長が一定でない場合のアクセス方式として、長いデータを高電力で送出することで転送成功率が向上可能な長データ優先送出方式を提案し、その評価を理論解析で行ない、スループット特性が向上することを示した。(3)マルチメディア衛星通信システムの構築多数局が参加する会議を衛星の同報性を利用して行なう場合、新規に発言を要求する場合、その発言要求を伝送するためのチャネルを使用せず、捕捉効果を用い回線交換のイメージで順次切りかえていく切替え方式を提案した

  • 周回衛星を用いた移動体通信網に関する多角的研究

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    本研究では周回衛星を用いた移動体通信の可能性を高めるため、実測に基づく測定パラメータを元にシミュレーションモデルを新たに構築し、移動体周回衛星通信の環境を正確にさせることに成功した。更にその再現モデルに基づき有効なアクセス方式などを提案し、その有効性を示した。具体的には以下の成果が挙げられる。1: 周回衛星を用いた移動体通信路モデルの確立従来の周回衛星に関する研究は断片的なものが多く、例えばシャドウイングの影響に関しても見通し率に基づく簡単な通信モデルが用いられている。本研究ではシャドウイングの継続の度合を継続分布の観点で仰角別に正確に求め、また見通し継続分布も合わせて求めることで、より具体的な通信モデルの構築を行なった。また、道路上では進行方向方面と建物方向方面ではシャドウイングの状況は大きくことなることが考えられるため、本研究では道路方向を0度として30度、60度、90度における各継続分布を個別に測定した。更に、樹木、電信柱、看板等の遮弊小物体に関してもその存在確率の観点から測定を行ない。それぞれ、仰角別に、方向別での通信路状況を正確にモデル化した。また、ライス分布とレイリー分布により具体的な通信特性が得られるシミュレーションを完成した。2: 周回衛星を用いた移動体通信方式の確立予定されるアプリケーションの許容遅延時間によって、構築するシステムは大きく異なる。音声通話、TV会議等の即時性の要求される場合は、衛星ダイバーシチを用い途切れない通信を行ない、即時性が重要でない電子メール等のデータアプリケーションではビル影等の障害物を初めて通信方式として有効活用するDAS(Directional Access using Shadowing)方式を提案し、建物による不要電波発射を押え、周波数の有効利用可能な方式であることを示した。3: 様々な軌道の周回衛星及び成層圏飛翔体との比較周回衛星の軌道は極軌道や傾斜角を持つ軌道など様々であり、また、その高度によっても通信特性は大きく異なる。本研究では成層圏飛翔体を含め、多様な周回衛星を用いた場合の特性を求め、その性能比較を行なった

  • 成層圏飛翔体を用いた移動体通信に関する多角的研究

     View Summary

    1:見通し継続角度分布、遮弊継続角度分布の取得飛翔体との通信を行なう場合、ビル等の構造物による遮弊が問題となる。研究では道路上を移動する車両との通信を想定し、道路方向に対し飛翔体が0°、30°、60°、90°に位置する場合の、各相対角における見通し状況を市街地における実測によって求めた。その際、各相対角度において、仰角で10°毎に水平方向に見通し可能な継続角度である見通し継続角度分布とシャドウイングである遮弊継続角度分布を都市規模別に大都市(新宿,渋谷)、中都市(浅草)、小都市(桐生)においてそれぞれ求めた。更に,各都市規模における建築物の高さ,幅の分布と道路からの距離に基づくモデル化を行ない,実測データに基づく値に近い特性が得られる通信路遮弊理論モデルを構築した.2:仰角別多重伝搬特性取得ビルの屋上にバルーンを上げそこから送信された信号を地上移動体で受信し,その受信電力レベルの変動を仰角別に調べた.実験の結果,低仰角では変動幅が大きく,高仰角では変動幅が小さく信号レベルと散乱波レベルの差であるC/M比では,低仰角で3dBから高仰角で24dBと大きく異なることが分かった.3:成層圏飛翔体通信路モデルの構築上記の2実験により、成層圏飛翔体通信路モデルを構築し,シミュレーションを行ない,都市別の通信状況をパケット欠損率の観点で表現した.その結果,大都市部と小都市部では欠損率が約3倍程度異なることなどを明らかにした.これらの成果は更に論文として発表予定である

  • 楕円変調方式の提案および実用化を目指した多角的研究

     View Summary

    本研究は楕円を用いた新しい変調方式を提案するものであるが、本研究期間内での成果として振幅、周波数、位相の各次元における楕円の変調方式を具体的なパラメータを用いて実現し、その性能評価を行った。まず長軸固定モードにおける、軸角度に基づく各種変調方式の確立、離心率の変化に基づく変調方式の確立と、位相変調との組み合わせであるEPSK方式を提案、構築を行い、各方式に関してはDSPによる実波形の生成、復調、周波数スペクトラムの測定、BER特性取得などを行った。具体的には、長軸固定モード、長軸回転モードにおける波形の導出は楕円信号処理装置、ならびに楕円信号処理システムで行いその基礎特性を取得した。長軸固定モードでは、オフセット長軸角度と離心率の組み合わせで各種伝送情報を表現した他、更に、振幅、位相、周波数での変調を組み合わせて、その特性を周波数スペクトラムの観点と、BER特性の観点で性能評価を行った。位相変調との組み合わせであるEPSK(Elliptical Phase Shift Keying)では4array,8arrayでの位相楕円変調方式を提案し、その特性を解析したほか、DS-CDMAとの組み合わせなど、様々な切り口で評価を行った。理論解析結果より従来方式と比べて信号対雑音特性など、高い性能が得られることが明らかになった

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Misc

  • Satellite-Terrestrial Cooperation System Based on Relaying through Mobile Vehicle Base Stations and Traffic Signal Base Stations

    松藤謙太, LIU Xuanning, 吉井一駿, ZHENNI Pan, 齋藤恵, LIU Jiang, 嶋本薫, 大倉拓也, 三浦周, 辻宏之, 吉村直子, 豊嶋守生

    電子情報通信学会技術研究報告(Web)   120 ( 404(RCS2020 203-261) )  2021

    J-GLOBAL

  • Dynamic Power Allocation in Parallel Interference Cancellation based NOMA Receiver

    DAWADI Bikash, ERNAWAN Mohamad Erick, PAN Zhenni, LIU Jiang, SHIMAMOTO Shigeru

    電子情報通信学会技術研究報告   117 ( 456(RCS2017 317-406) )  2018

    J-GLOBAL

  • Cooperative Traffic Light Control Approach for Reducing Traffic Congestion with V2I Network

    WANG Huan, LIU Jiang, PAN Zhenni, KOSHIMIZU Takashi, SHIMAMOTO Shigeru

    電子情報通信学会大会講演論文集(CD-ROM)   2017  2017

    J-GLOBAL

  • BS-6-24 POSITION ACCURACY FOR INDOOR LOCALIZATION SYSTEM EMPLOYING VISIBLE LIGHT COMMUNICATION(BS-6.Network and service Design, Control and Management)

    Khourn Khemry, Liu Jiang, Shimamoto Shigeru

    Proceedings of the Society Conference of IEICE   2015 ( 2 ) "S - 61"-"S-62"  2015.08

    CiNii

  • BS-3-34 Off Loading based Global LEO Satellite Network employing Adaptive Beam Forming(BS-3. Advanced Technologies in the Design, Management and Control for Future Innovative Communication Network)

    Numakami Akira, Gaytan Lilian del Consuelo Hernandez Ruiz, Nuon Chandarong, Liu Jiang, Shimamoto Shigeru

    Proceedings of the IEICE General Conference   2015 ( 2 ) "S - 72"-"S-73"  2015.02

    CiNii

  • BS-1-4 Unmanned Aerial Vehicle based Missing People Detection System employing Phased Array Antenna

    Ando Taisuke, Aomi Naoto, Inata Hikari, Liu Jian, Shimamoto Shigeru

    Proceedings of the IEICE General Conference   2015 ( 1 ) "S - 7"-"S-8"  2015.02

    CiNii

  • Study on Access schemes for Disaster Network System employing UAV

    Aso Kento, Aomi Naoto, Sotheara Say, Shimamoto Shigeru

    Technical report of IEICE. RCS   113 ( 456 ) 527 - 532  2014.03

     View Summary

    Currently, there are a lot of issues to locate the missing person due to a large-scale earthquake disaster. The establishment of a rapid rescue system for the disaster site will be very important in the future. In this study, we utilize Unmanned Aircraft that can fly in the disaster areas called Unmanned Aerial Vehicle (UAV) to locate the missing person by flew over the site and taking pictures information , also exchanging information with the sensor technology. UAV is commonly used as a reconnaissance aircraft in China and United States, however we propose a model to use UAV as a searching machine, by means of sensor technology. The purpose of this proposed model is to create a system that can locate the missing person using the signal transmitted between UAV and the wrist watch transponder. We fabricate the wrist watch transponder and measure the system performances including transmission success rate between UAV and the sensors for the communication quality, average transmission delay, bit error rate and packet error rate.

    CiNii

  • Energy-sensitive Handoff Scheme Employing RF Fingerprint For Cell Sizing Based Heterogeneous Cellular Networks

    Pan Zhenni, Saito Megumi, Liu Jiang, Shimamoto Shigeru

    Technical report of IEICE. RCS   113 ( 456 ) 145 - 150  2014.03

     View Summary

    The energy optimization in small cell involved heterogeneous networks has been considered as an emerging topic which enables a balance between the power consumption and capacity issues. In this paper, we propose an energy-sensitive handoff scheme for mobile macro user equipment (MUE) in the sleep mode involved cell sizing based macro-femto two-tier networks. The proposed scheme aims at achieving high handoff stability with low MUE power consumption by dynamically scheduling the mobile MUEs switch to the expandable indoor femto access point (FAP) and active macro base station (MBS) with a variable probability. The unique RF fingerprint (RFF) based localization is employed to provide energy-efficient small-cell detection with a flexible matching region. The transmit power of the MUEs for FAP sensing can be adaptively adjusted refer to the instantaneous traffic loads and reference location. Comprehensive evaluations are conducted with a tradeoff and show our proposed scheme has a positive influence on obtaining energy-efficient and QoS satisfiable handoff strategy in the macro-femto two-tier scenarios.

    CiNii

  • BI-2-13 The Study of Missing People Detection System employing UAV

    Oh Woojin, Aso Kento, Zhou Muye, David Donald Mrema, Liu Jian, Shimamoto Shigeru

    Proceedings of the IEICE General Conference   2013 ( 1 ) "SS - 83"-"SS-84"  2013.03

    CiNii

  • BS-1-7 ENERGY HARVESTING BASED OPTICAL WIRELESS IDENTIFICATION SCHEME EMPLOYING THINFILM CORNER CUBE RETROREFLECTOR

    Khoum Khemry, Liu Jiang, Noonpakdee Wasinee, Shimamoto Shigeru

    Proceedings of the IEICE General Conference   2013 ( 2 ) "S - 13"-"S-14"  2013.03

    CiNii

  • A Study on RF Signal Relay System employing Optical Wireless Communication

    LIU Jiang, TAKANO Hiroshi, SHIMAMOTO Shigeru

    Technical report of IEICE. LQE   108 ( 261 ) 23 - 28  2008.10

     View Summary

    This paper studies an effective relay system based on optical wireless communication between the mobile terminal (MT) and the relay station to eliminate the drawback of electromagnetic wave interference to electro-medical apparatus in indoor communication system. RF subcarrier optical communication system using Intensity-modulated Direct-detection (IM/DD) is adopted and its transmission performance is evaluated by simulation. Moreover, optical signal and RF signal diversity receiving method is proposed and quantitatively evaluated in downlink. An optical spatial transmit diversity scheme based on subcarrier phase control is also studied in downlink.

    CiNii

  • B-5-2 A Proposal of Interference Cancellation Scheme Based on IQ-Balanced Transmission

    Liu Jiang, Shimamoto Shigeru

    Proceedings of the IEICE General Conference   2006 ( 1 ) 354 - 354  2006.03

    CiNii

  • B-10-68 A Study on Medium-long Distance Optical Wireless Communication Network Employing Reflectors

    Liu Jiang, Li Wei, Sando Jin, Shimamoto Shigeru, Shimizu Kayo, Fujikawa Chiemi, Kodate Kashiko

    Proceedings of the Society Conference of IEICE   2005 ( 2 ) 286 - 286  2005.09

    CiNii

  • A Study on 5GHz Digital Data Communication for Aircraft Traffic Control

    GUAN Xu, TU Ho Dac, TSUDA Yoshio, SHIMAMOTO Shigeru, KITAORI Jun, NAKATANI Yasuyoshi, KATO Satoshi

    Technical report of IEICE. SANE   104 ( 237 ) 1 - 6  2004.07

     View Summary

    VHP spectrum used in aircraft wireless communication is expected to become saturated due to the enormous increase in aircraft traffic. However, 5GHz frequency band assigned for aircraft radio navigation still hasn't been utilized for that purpose in Japan. Increased aircraft communication traffic combined with increased demand on data transmission, has enhanced the need of employing 5GHz frequency band to aircraft communication. This paper aims to investigate the possible utilization of 5GHz frequency band to data transmission in aircraft communication. To do this, we carried out some flight tests by using an experimental aircraft. Transmission characteristics under 5GHz frequency band have been investigated, and we considered the characteristics in this paper.

    CiNii

  • 異種スロットを混在させた可変長パケット通信方式

    嶋本薫

    信学技報     IN91 - 197  1992

    CiNii

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Syllabus

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Overseas Activities

  • 次世代ワイヤレスネットワークに関する多角的な研究

    2008.07
    -
    2008.12

    アメリカ   スタンフォード大学

Sub-affiliation

  • Faculty of Science and Engineering   Graduate School of Fundamental Science and Engineering

  • Affiliated organization   Global Education Center

Research Institute

  • 2022
    -
    2024

    Waseda Research Institute for Science and Engineering   Concurrent Researcher

  • 2022
    -
    2024

    Global Information and Telecommunication Institute   Concurrent Researcher

Internal Special Research Projects

  • 楕円変調方式の提案及び実用化を目差した多角的研究

    2003  

     View Summary

    本研究は楕円を用いた新しい変調方式を提案するものであるが、本研究期間内での成果として振幅、周波数、位相の各次元における楕円の変調方式を具体的なパラメータを用いて実現し、その性能評価を行った。 まず長軸固定モードにおける、軸角度に基づく各種変調方式の確立、離心率の変化に基づく変調方式の確立と、位相変調との組み合わせであるEPSK方式を提案、構築を行い、各方式に関してはDSPによる実波形の生成、復調、周波数スペクトラムの測定、BER特性取得などを行った。 具体的には、長軸固定モード、長軸回転モードにおける波形の導出は楕円信号処理装置、ならびに楕円信号処理システムで行いその基礎特性を取得した。長軸固定モードでは、オフセット長軸角度と離心率の組み合わせで各種伝送情報を表現した他、更に、振幅、位相、周波数での変調を組み合わせて、その特性を周波数スペクトラムの観点と、BER特性の観点で性能評価を行った。 長軸回転モードでは、長軸の回転速度、回転方向(右回転、左回転)、あるいは回転速度、回転方向の変化のさせ方、離心率のパラメータを各種組み合わせ、それぞれの周波数スペクトラムと、BER特性の関係について調べた。 更に、振幅、位相、周波数変調と組み合わせ、それぞれの特性も導出する。 また、同時に理論モデルの構築も行い、BER等の理論式の検討を行った。また、受信に関してはコリレイターを用いた方式で従来方式よりも優れた特性が得られているので、具体的なシステムとして検討を行った  楕円変調波形は全て楕円信号処理システムおよび楕円信号処理装置で生成され、現有設備であるオシロスコープにより波形を解析した。 

  • 成層圏飛翔体を用いた移動体通信における電波伝搬特性の取得に関する研究

    2000  

     View Summary

     成層圏飛翔体や低軌道衛星などを用いた通信システムでは、構造物による反射の影響により電波伝播は到来方向の仰角別に異なる. 本研究では仰角別に異なると考えられるそれら多重伝搬特性を、実測実験に基づいて測定し、更に様々な周波数で測定し、その比較を行った。まず、送受信用アンテナとして2.4GHz,および1.2GHzでの極力指向性特性をもたないループ型のターンスタイルアンテナ、スリーブアンテナ更には折り曲げタイプのスリーブアンテナをを作成し、その性能を実測実験において測定した。その際、市販のモノポールアンテナとの比較を行い、指向性特性や定在波を測定し、定在波では概ね2.0以下であり、アンテナ利得もほぼ所定の値を示すことを確認した。 次にビルの屋上からアンテナを迫り出させて測定実験を行うため、アルミ性ポールにアンテナ所持機構を持たせるためのボックスを作成し、位相差給電機構が問題なく収納でき、かつ強風にも耐えられるよう強固に固定する支持機構を作成した。また、移動車両においては車両の頂上に受信アンテナを設置するための所持機構を作成し振動等にも耐えられる様工夫を行った。測定データはスペクトラムアナライザにGPIBインターフェイスを持たせたノート型パーソナルコンピュータで取得し、ワークステーションでデータの解析を行った。実験結果は仰角が大きくなるにつれ直接波と間接波の比率における直接波の成分が相対的に大きくなることから受信信号レベルの変動幅が小さくなることが定量的に得られた。今後の課題はこれらのデータをまとめて飛翔体通信のシミュレーションを作成し、通信方式提案やその性能評価を行うことである。これらの成果は電子情報通信学会研究会、論文誌等において発表を行う予定である。