• Title/Summary/Keyword: Indoor mobile communication systems

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Hybrid Algorithmic Framework Using IMU and WPS for Smart Phone Positioning Systems (스마트폰 IMU와 WPS를 결합한 복합 측위 방법론)

  • Kim, Jae-Hoon;Kang, Suk-Yon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.8
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    • pp.663-673
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    • 2013
  • The drastic growth of mobile communication and spreading of smart phone make the significant attention on Location Based Service. The one of most important things for vitalization of LBS is the accurate estimating position for mobile object. Focusing on IMU deployed in smart phone, we develop a hybrid positioning estimation framework with a combination of WPS. The developed approaches can strengthen the advantages of independent indoor applicability of IMU. The estimation of IMU is efficiently compensated by radio fingerprint based Wi-Fi Positioning System. We put a focus especially on the hybrid algorithmic framework. Compared on the existing approaches of WPS or IMU, we achieve the comparable higher performance on both of average error of estimation and deviation of errors. Furthermore test-bed based on smart phone platform is practically developed and all data have been harvested from the actual measurement of test indoor area. This can approve the practical usefulness of proposed framework.

A study on indoor navigation system using localization based on wireless communication (무선통신기반 위치인식을 이용한 실내 내비게이션 시스템에 관한 연구)

  • Kim, Jung-Ha;Lee, Sung-Geun;Kim, Jong-Su;Kim, Jeong-Woo;Seo, Dong-Hoan
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.1
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    • pp.114-120
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    • 2013
  • Recently, navigation systems based on wireless communication have been applied to the internal structures such as building or ship. If a stable azimuth information is obtained, these systems can effectively guide the direction of the user's progress through the information and then can improve the performance of guidance. Since conventional method which has acquired an azimuth information using geomagnetic and acceleration sensor(azimuth sensor hereafter) is sensitive to the effects of the magnetic field, it has unstable error range according to the surrounding environment. In order to improve these problems, this paper presents a new relative azimuth estimation algorithm using the displacement of a mobile node and its rotation angle based on Wireless communication. For the performance assessment of the proposed algorithm, experiments using rotating arm are performed and the results are confirmed that the proposed system can estimate the relative azimuth without using additional sensors.

Distance Estimation Using Convolutional Neural Network in UWB Systems (UWB 시스템에서 합성곱 신경망을 이용한 거리 추정)

  • Nam, Gyeong-Mo;Jung, Tae-Yun;Jung, Sunghun;Jeong, Eui-Rim
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.10
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    • pp.1290-1297
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    • 2019
  • The paper proposes a distance estimation technique for ultra-wideband (UWB) systems using convolutional neural network (CNN). To estimate the distance from the transmitter and the receiver in the proposed method, 1 dimensional vector consisted of the magnitudes of the received samples is reshaped into a 2 dimensional matrix, and by using this matrix, the distance is estimated through the CNN regressor. The received signal for CNN training is generated by the UWB channel model in the IEEE 802.15.4a, and the CNN model is trained. Next, the received signal for CNN test is generated by filed experiments in indoor environments, and the distance estimation performance is verified. The proposed technique is also compared with the existing threshold based method. According to the results, the proposed CNN based technique is superior to the conventional method and specifically, the proposed method shows 0.6 m root mean square error (RMSE) at distance 10 m while the conventional technique shows much worse 1.6 m RMSE.

A Study on Experiment of Transmission Power Assignment for Indoor TVWS Wireless Communication System (실내 TVWS 무선통신을 위한 송신 전력 설정 실험에 관한 연구)

  • Yun, Deok-Won;Chang, Hyung-Min;Lee, Won-Cheol
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38B no.10
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    • pp.851-860
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    • 2013
  • To overcome a scarcity of radio resources to mobile broadband service, the usage of TV white space gains much attraction around the world. This paper carries out an interference analysis either by performing realistic experiments or by executing statistical Monte-Carlo simulation to exploit interference probability. The results obtained from experiments are compared to those from simulations in order to clarify the coexistence of utilization of TV band devices (TVBD) in indoor circumstances. Along the execution of our experiment in the presence of DTV receiver, we apply to a variety of transmission parameters proposed in FCC for TVBD. According to experimental and simulation works, the allowable transmission powers of TVBD systems are exploited for the plausible which are coexist on the first as well as the second adjacent frequency bands. Throughout results, it can conclude that TVBD systems can be coexisted via achieving proper transmission powers depending on the locations of themselves without showing harmful interference to DTV reception.

Smart Windows and Doors Platform for Providing Optimized Inner Environment (최적의 실내 환경을 제공하기 위한 스마트 창호 플랫폼)

  • Cho, Yong-Hyun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.25 no.5
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    • pp.464-469
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    • 2015
  • This paper presents the smart system platform for remotely controlling the windows and doors system(WDS), which gathers and analyzes the state of WDS and the environmental data for preventing crimes and keeping a pleasant indoor. In particular, standard API between the smart WDS platform and the smart home platform has been presented to be easy to a home services, such as security, safety, and home appliance control. The private gateway of wire and wireless communication interfaces has been developed to remotely control and monitor the WDS for anytime and anyplace solving the crime prevention and ventilation problem. Web-and App-based user interface in order to detect the opening and shutting states and remotely control WDS have also been developed to support the mobile environment, respectively.

A Detailed Design Study on VDES Test Network Construction and Service Solution Development (VDES 시험망 구축 및 서비스 솔루션 개발에 관한 상세설계 연구)

  • CHOI, Seung-Hyun;KIM, Juntae;Park, Kaemyoung;JANG, Tae Hun;KIM, Pu Reum;JEONG, Woojin;SONG, Jae Min
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2019.11a
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    • pp.259-260
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    • 2019
  • Through Korean Smart-Navigation Project we are tasking with a VDES test network construction and service solution development. In this task, we design a structure that interoperates the VDES network with the service host/client simulator which is communication framework for efficient and reliable and seamless service. The proposed structure includes interface design between VDES test equipments which is VDES shore station, mobile station, gate way, service host and client. And detailed design includes message definition, interface design, operation scenario, equipment design and implementation for VDES test network. After implementing these test equipments with proposed design, we will firstly proceed the test equipment integration and interface test indoors for VDES test network. After fully verifing the VDES test network through indoor tests, we will construct the VDES shore station and mobile station and conduct the sea area tests by 2020.

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Mitigating Techniques for OFDMA System Based on SDD (SDD 기반 OFDMA 시스템을 위한 간섭 완화 기법)

  • Park, Chang-Hwan;Ko, Yo-Han;Kim, Moo-Chul;Park, Kyung-Won;Jeon, Won-Gi;Paik, Jong-Ho;Lee, Seok-Pil;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.8C
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    • pp.742-749
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    • 2009
  • In this paper, we propose mitigation techniques using time-domain shortening filter (TSF) and frequency-domain shortening filter (FSF) to overcome inter-block interference (IBn and inter-carrier interference (ICn due to the time difference of arrival (TDoA) and carrier frequency offset (CFO) between downlink and uplink signals from access point (AP) and subscriber station (SS) in synchronous digital duplexing (SDD)/orthogonal frequency division multiple access (OFDMA) systems for indoor wireless communication. The proposed TSF and FSF maximize SIR for shortening in time (SIRST) and SINR for shortening in frequency (SINRSF), respectively, by using channel impulse responses and timing information among stations, obtained from mutual ranging procedure. It is verified by computer simulation that the proposed TSF and FSF reduce effectively the effects of IBI and ICI in the SDD/OFDMA systems.

NFC-based Smartwork Service Model Design (NFC 기반의 스마트워크 서비스 모델 설계)

  • Park, Arum;Kang, Min Su;Jun, Jungho;Lee, Kyoung Jun
    • Journal of Intelligence and Information Systems
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    • v.19 no.2
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    • pp.157-175
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    • 2013
  • Since Korean government announced 'Smartwork promotion strategy' in 2010, Korean firms and government organizations have started to adopt smartwork. However, the smartwork has been implemented only in a few of large enterprises and government organizations rather than SMEs (small and medium enterprises). In USA, both Yahoo! and Best Buy have stopped their flexible work because of its reported low productivity and job loafing problems. In addition, according to the literature on smartwork, we could draw obstacles of smartwork adoption and categorize them into the three types: institutional, organizational, and technological. The first category of smartwork adoption obstacles, institutional, include the difficulties of smartwork performance evaluation metrics, the lack of readiness of organizational processes, limitation of smartwork types and models, lack of employee participation in smartwork adoption procedure, high cost of building smartwork system, and insufficiency of government support. The second category, organizational, includes limitation of the organization hierarchy, wrong perception of employees and employers, a difficulty in close collaboration, low productivity with remote coworkers, insufficient understanding on remote working, and lack of training about smartwork. The third category, technological, obstacles include security concern of mobile work, lack of specialized solution, and lack of adoption and operation know-how. To overcome the current problems of smartwork in reality and the reported obstacles in literature, we suggest a novel smartwork service model based on NFC(Near Field Communication). This paper suggests NFC-based Smartwork Service Model composed of NFC-based Smartworker networking service and NFC-based Smartwork space management service. NFC-based smartworker networking service is comprised of NFC-based communication/SNS service and NFC-based recruiting/job seeking service. NFC-based communication/SNS Service Model supplements the key shortcomings that existing smartwork service model has. By connecting to existing legacy system of a company through NFC tags and systems, the low productivity and the difficulty of collaboration and attendance management can be overcome since managers can get work processing information, work time information and work space information of employees and employees can do real-time communication with coworkers and get location information of coworkers. Shortly, this service model has features such as affordable system cost, provision of location-based information, and possibility of knowledge accumulation. NFC-based recruiting/job-seeking service provides new value by linking NFC tag service and sharing economy sites. This service model has features such as easiness of service attachment and removal, efficient space-based work provision, easy search of location-based recruiting/job-seeking information, and system flexibility. This service model combines advantages of sharing economy sites with the advantages of NFC. By cooperation with sharing economy sites, the model can provide recruiters with human resource who finds not only long-term works but also short-term works. Additionally, SMEs (Small Medium-sized Enterprises) can easily find job seeker by attaching NFC tags to any spaces at which human resource with qualification may be located. In short, this service model helps efficient human resource distribution by providing location of job hunters and job applicants. NFC-based smartwork space management service can promote smartwork by linking NFC tags attached to the work space and existing smartwork system. This service has features such as low cost, provision of indoor and outdoor location information, and customized service. In particular, this model can help small company adopt smartwork system because it is light-weight system and cost-effective compared to existing smartwork system. This paper proposes the scenarios of the service models, the roles and incentives of the participants, and the comparative analysis. The superiority of NFC-based smartwork service model is shown by comparing and analyzing the new service models and the existing service models. The service model can expand scope of enterprises and organizations that adopt smartwork and expand the scope of employees that take advantages of smartwork.