• Title/Summary/Keyword: Relaying Signals

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Hardware Design of IED using DSP for Power Transformer Protection (DSP를 이용한 전력용 변압기용 IED의 하드웨어 설계)

  • Park C. W.;Jung Y. M.;Ha K. J.;Koo C. S.;Shin M. C.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.363-365
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    • 2004
  • This paper proposes a hardware implementation of intelligent electronic device for power transformer protection. And proposes an advanced main protection algorithm by voltage-current trend and flux-differential current slope characteristics. The secondary protection functions include UR, OCGR, OVR, and W etc. The main board of IED is based on the DSP chip TMS32C32 processor The IED was tested with relaying signals obtained for EMTP simulation package.

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Outage Analysis and Optimization for Time Switching-based Two-Way Relaying with Energy Harvesting Relay Node

  • Du, Guanyao;Xiong, Ke;Zhang, Yu;Qiu, Zhengding
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.2
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    • pp.545-563
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    • 2015
  • Energy harvesting (EH) and network coding (NC) have emerged as two promising technologies for future wireless networks. In this paper, we combine them together in a single system and then present a time switching-based network coding relaying (TSNCR) protocol for the two-way relay system, where an energy constrained relay harvests energy from the transmitted radio frequency (RF) signals from two sources, and then helps the two-way relay information exchange between the two sources with the consumption of the harvested energy. To evaluate the system performance, we derive an explicit expression of the outage probability for the proposed TSNCR protocol. In order to explore the system performance limit, we formulate an optimization problem to minimize the system outage probability. Since the problem is non-convex and cannot be directly solved, we design a genetic algorithm (GA)-based optimization algorithm for it. Numerical results validate our theoretical analysis and show that in such an EH two-way relay system, if NC is applied, the system outage probability can be greatly decreased. Moreover, it is shown that the relay position greatly affects the system performance of TSNCR, where relatively worse outage performance is achieved when the relay is placed in the middle of the two sources. This is the first time to observe such a phenomena in EH two-way relay systems.

Rate-Aware Two-Way Relaying for Low-Cost Ship-to-Ship Communications (저비용 선박간 통신을 위한 전송률 인지 양방향 릴레이 기법)

  • Wang, Jinsoo;Kim, Sun Yong;Jeong, Min-A;Lee, Seong Ro;Kim, Yun Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.8
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    • pp.651-659
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    • 2014
  • In this paper, we consider a two way relay network for ship-to-ship communications in a fleet, where two communicating ships exchange the information with the help of a multi-antenna relay ship. For the network, we propose a rate-aware three-phase analog network coding to improve the reliability of the information exchange with asymmetric rates. The proposed scheme allows low-complex implementation of the relay without channel estimation by generating an improved analog network coded signal with the orthogonally received signals from two ships by using only the received signal power at each antenna. In addition, the proposed scheme reduces outages in the data exchange at asymmetric rates by adopting a rate-aware relay power allocation, which is confirmed by evaluating the outage performance via simulation.

Optimal Power Allocation for Spatial Division Multiplexing Scheme at Relays in Multiuser Distributed Beamforming Networks (다중 사용자 분산 빔포밍 네트워크의 중계기에서의 공간 분할 다중화 기법을 위한 최적 전력 할당 방법)

  • Ahn, Dong-Gun;Seo, Bang-Won;Jeong, Cheol;Kim, Hyung-Myung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.4A
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    • pp.360-370
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    • 2010
  • In this paper, a distributed beamforming problem is considered in an amplify-and-forward (AF) wireless relay network consist of multiple source-destination pairs and relaying nodes. To exploit degree of freedom of the number of beamformers, in the first step, we proposed that the sources transmit their signals through orthogonal channels. During the second step, the relays transmit their received signals multiplied by complex weights to amplify and compensate for phase changes introduced by the backward channels through one common channel. The optimal beamforming vectors are obtained through minimization of the total relay transmit power while the signal-to-interference-plus-noise ratios (SINRs) at the destinations are above certain thresholds to meet a quality of services (QoSs) level. In the numerical example, it is shown that the proposed scheme needs less transmit power for moderate network data rates than other schemes, such as space division multiplexing or time-division multiplexing scheme.

Relaying of 4G Signal over 5G Suitable for Disaster Management following 3GPP Release 18 Standard

  • Jayanta Kumar Ray;Ardhendu Shekhar Biswas;Arpita Sarkar;Rabindranath Bera;Sanjib Sil;Monojit Mitra
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.2
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    • pp.369-390
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    • 2023
  • Technologies for disaster management are highly sought areas for research and commercial deployment. Landslides, Flood, cyclones, earthquakes, forest fires and road/train accidents are some causes of disasters. Capturing video and accessing data in real time from the disaster site can help first responders make split second decisions which may save human lives and valuable resource destructions. In this context the communication technologies performing the task should have high bandwidth and low latency which only 5G can deliver. But unfortunately in India, deployment of the 5G mobile communication systems is yet to give a shape and again in remote areas unavailability of 4G signals is still severe. In this situation the authors have proposed, simulated and experimented a 4G-5G communication scheme where from the disaster site the signals will be transmitted by a 5G terminal to a nearby 4G-5G gateway installed in a mobile vehicle. The received 5G signal will be further relayed by the 4G-5G gateway to the fixed 4G base station for onward transmission towards the disaster management station for decision making, deployment and relief monitoring. The 4G-5G gateway acts as a relay and converter of 5G signal to 4G signal and vice versa. This relayed system can be further mounted on a vehicle mounted relay (VMR) as proposed by 3GPP in Release 18. The scheme is also in the same line of context with Verizon's, "Tactical Humanitarian Operations Response" (THOR) vehicle concept. The performance of the link is studied in different channel conditions, the throughput achieved is superb. The authors have implemented the above mentioned system towards smart campus networking and monitoring landslides activities which are common in their regions.

Space-Frequency Block Coded OFDMA Transmission System using Multiple Relays for Shadow Area (음영 지역을 위한 다중 중계기 기반의 주파수 공간 블록 부호화 OFDMA 전송 시스템)

  • Won, Hui-Chul
    • Journal of Korea Society of Industrial Information Systems
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    • v.19 no.4
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    • pp.1-8
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    • 2014
  • In order to cope with shadow areas and to extend cell coverage, relay-assisted wireless communication systems have been widely studied. In this paper, we propose a space-frequency(SF) block coded orthogonal frequency division multiple access(OFDMA) transmission system in a relaying multi-path shadow area. The receiving performance of mobile station in a shadow area can be improved by applying SF block code to the recovered signals of multiple relays before re-transmitting them. The simulation result shows that the proposed SF block coded OFDMA transmission system considerably outperforms the conventional single-path OFDMA transmission system.

Cooperative Multi-relay Scheme for Secondary Spectrum Access

  • Duy, Tran-Trung;Kong, Hyung-Yun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.4 no.3
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    • pp.273-288
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    • 2010
  • In this paper, we propose a cooperative multi-relay scheme for a secondary system to achieve spectrum access along with a primary system. In the primary network, a primary transmitter (PT) transmits the primary signal to a primary receiver (PR). In the secondary network, N secondary transmitter-receiver pairs (ST-SR) selected by a centralized control unit (CCU) are ready to assist the primary network. In particular, in the first time slot, PT broadcasts the primary signal to PR, which is also received by STs and SRs. At STs, the primary signal is regenerated and linearly combined with the secondary signal by assigning fractions of the available power to the primary and secondary signals respectively. The combined signal is then broadcasted by STs in a predetermined order. In order to achieve diversity gain, STs, SRs and PT will combine received replicas of the primary signal, using selection combining technique (SC). We derive the exact outage probability for the primary network as well as the secondary network. The simulation results are presented to verify the theoretical analyses.

EMG-based Real-time Finger Force Estimation for Human-Machine Interaction (인간-기계 인터페이스를 위한 근전도 기반의 실시간 손가락부 힘 추정)

  • Choi, Chang-Mok;Shin, Mi-Hye;Kwon, Sun-Cheol;Kim, Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.8
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    • pp.132-141
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    • 2009
  • In this paper, we describe finger force estimation from surface electromyogram (sEMG) data for intuitive and delicate force control of robotic devices such as exoskeletons and robotic prostheses. Four myoelectric sites on the skin were found to offer favorable sEMG recording conditions. An artificial neural network (ANN) was implemented to map the sEMG to the force, and its structure was optimized to avoid both under- and over-fitting problems. The resulting network was tested using recorded sEMG signals from the selected myoelectric sites of three subjects in real-time. In addition, we discussed performance of force estimation results related to the length of the muscles. This work may prove useful in relaying natural and delicate commands to artificial devices that may be attached to the human body or deployed remotely.

Fault Locator using GPS Time-synchronized Phasor for Transmission Line (송전선로의 동기페이저를 이용한 고장점 표정장치)

  • Lee, Kyung-Min;Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.65 no.1
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    • pp.47-52
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    • 2016
  • Fault location identification in the transmission line is an essential part of quick service restoration for maintaining a stable in power system. The application of digital schemes to protection IEDs has led to the development of digital fault locators. Normally, the impedance measurement had been used to for the location detection of transmission line faults. It is well known that the most accurate fault location scheme uses two-ended measurements. This paper deals with the complete design of a fault locator using GPS time-synchronized phasor for transmission line fault detection. The fault location algorithm uses the transmitted relaying signals from the two-ended terminal. The fault locator hardware consists of a Main Processor Unit, Analog Digital Processor Unit, Signal Interface Unit, and Power module. In this paper, sample real-time test cases using COMTRADE format of Omicron apparatus are included. We can see that the implemented fault locator identified all the test faults.

Contract Theory Based Cooperative Spectrum Sharing with Joint Power and Bandwidth Optimization

  • Lu, Weidang;He, Chenxin;Lin, Yuanrong;Peng, Hong;Liu, Xin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.12
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    • pp.5803-5819
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    • 2017
  • In this paper, we proposed a contract theory based cooperative spectrum sharing scheme with joint power and bandwidth optimization under asymmetric information, where the primary user (PU) does not know the secondary users' (SUs) private information. To improve performance, PU needs to provide incentives to stimulate nearby SUs to help forward its signal. By using contract theory, PU and SUs' negotiations are modeled as a labor market. PU and SUs act as the employer and employees, respectively. Specifically, SUs provide labor (i.e. the relay power, which can be used for forwarding PU's signal) in exchange for the reward (i.e. the spectrum access bandwidth which can be used for transmitting their own signals). PU needs to overcome a challenge how to balance the relationship between contributions and incentives for the SUs. We study the optimal contract design which consists of relay power and spectrum access bandwidth allocation. We show that the most efficient SUs will be hired by the PU to attend the cooperative communication. PU can achieve the same maximum utility as in the symmetric information scenario. Simulation results confirm that the utility of PU is significantly enhanced with our proposed cooperative spectrum sharing scheme.