• 제목/요약/키워드: Relaying Signals

검색결과 74건 처리시간 0.021초

TSR 릴레이를 활용한 무선 전력 Backscatter 통신 성능 분석 (Performance Analysis of Wireless-powered Backscatter Communication with TSR-based Relay)

  • 박시우;박재현;황규성
    • 한국멀티미디어학회논문지
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    • 제23권9호
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    • pp.1164-1170
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    • 2020
  • In this paper, we consider the wireless-powered backscatter communication which consists of a power beacon, a source, a relay, and a destination. For the proposed wireless-powered backscatter communication, the source transmits its signals to both the relay and the destination via a backscattering channel and the relay which has a rechargeable battery performs an energy harvesting as well as an information forwarding based on the time switching relay (TSR) protocol. Based on the decode-and-forward (DF) relay transmission, we investigate performances of the proposed system in terms of outage probability and transmission rate in which the exact performance analysis of outage probability is given. Finally, some numerical examples are given to verify our provided analytical results for different system conditions.

Improving Physical-Layer Security for Full-duplex Radio aided Two-Way Relay Networks

  • Zhai, Shenghua;An, Jianping
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권2호
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    • pp.562-576
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    • 2020
  • The power allocation optimization problem is investigated for improving the physical-layer security in two-way relaying networks, where a full-duplex relay based half-jamming protocol (HJP-FDR) is considered. Specially, by introducing a power splitter factor, HJP-FDR divides the relay's power into two parts: one for forwarding the sources' signals, the other for jamming. An optimization problem for power split factor is first developed, which is proved to be concave and closed-form solution is achieved. Moreover, we formulate a power allocation problem to determine the sources' power subject to the total power constraint. Applying the achieved closed-form solutions to the above-mentioned problems, a two-stage strategy is proposed to implement the overall power allocation. Simulation results highlight the effectiveness of our proposed algorithm and indicate the necessity of optimal power allocation.

IOTA-OFDM/OQAM 시스템 기반의 복호 후 전송 협력 통신 (Decode-and-Forward Cooperative Communication Based on IOTA-OFDM/OQAM System)

  • 김재진;김동호
    • 한국통신학회논문지
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    • 제39A권12호
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    • pp.777-779
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    • 2014
  • 본 논문에서는 보호구간이 삽입된 OFDM 시스템의 단점을 개선한 IOTA-OFDM/OQAM 시스템을 소개한다. 또한 이를 기반으로 하는 DF 협력 통신 모델을 제안한다. 제안 모델의 최종 수신단은 소스와 릴레이로부터 수신한 직교 신호를 MRC 기법으로 결합한다. 이로 인해 얻게 되는 다이버시티 이득으로 제안 모델이 기존 시스템 대비 더 나은 BER 성능을 얻음을 전산 모의실험을 통해 확인하였다.

지능형 디지탈 보호계전 알고리즘 연구 (Study of an algorithm for intelligent digital protective relaying)

  • 신현익;이성환;강신준;김정한;김상철
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.343-346
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    • 1996
  • A new method for on-line induction motor fault detection is presented in this paper. This system utilizes unsupervised-learning clustering algorithm, the Dignet, proposed by Thomopoulos etc., to learn the spectral characteristics of a good motor operating on-line. After a sufficient training period, the Dignet signals one-phase ground fault, or a potential failure condition when a new cluster is formed and persists for some time. Since a fault condition is found by comparison to a prior condition of the machine, on-line failure prediction is possible with this system without requiring information on the motor of load characteristics.

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진행파를 이용한 송전선로의 고장점 표정 알고리즘 (A Fault Location Algorithm for a Transmission Line Using Travelling Waves)

  • 강상희;김진한
    • 대한전기학회논문지:전력기술부문A
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    • 제53권10호
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    • pp.542-549
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    • 2004
  • The conventional fault location algorithms based on the travelling waves have an inherent problem. In cases of the close-up faults occurring near the relaying point and of the faults having zero degree inception angle of voltage signals, the conventional algorithms can not estimate an accurate fault distance. It is because the shapes of travelling waves are near sinusoidal in those cases. A new method solving this problem is presented in this paper. An FIR(Finite Impulse response) filter which makes high frequency components prominent and makes the power frequency component and dc-offset attenuated is used. With this method, the cross-correlation peak is to be very clear when a close-up fault or a fault having near zero-degree inception angle occurs. The cross-correlation peaks can be clearly distinguished and accurate fault location is practically possible consequently. A series of simulation studies using EMTP(Electromagnetic Transients Program) show that the proposed algorithm can calculate an accurate fault distance having maximum 2% or less error.

Interference Alignment in Two-way Relay Channel with Compute-and-Forward

  • Jiang, Xue;Zheng, Baoyu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권2호
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    • pp.593-607
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    • 2016
  • This paper analyzes interference alignment in the two-way relay network with compute-and-forward in both single relay and multiple relays networks. The advantages of compute-and-forward over other relaying strategies are that it can relay only linear combinations of the useful signals and remove the noise. The algorithm proposed in this paper adopts the criterion of maximum SINR to derive the pre-coding matrix. The experimental results show that the performance of interference alignment in two-way relay channel via compute-and-forward is better than that of amplify-and-forward, and the total sum rate in the two-way multiple relay networks is larger than that in the two-way single relay networks.

발전기 계자보호를 위한 계자상실 알고리즘에 관한 연구 (A Study on Loss of Excitation Algorithm for Generator Field Protection)

  • 박유영;박철원
    • 전기학회논문지P
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    • 제63권4호
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    • pp.368-372
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    • 2014
  • The most widely used scheme for detecting loss of excitation on generator is used to sense apparent impedance from generator terminals. This paper presents loss of excitation algorithm using DFT filter based negative offset mho elements for generator field protection. It's algorithm includes two negative mho characteristics looking in the generator. The generator control system was modeled by PSCAD/EMTDC software, and then the proposed algorithm was tested by the collecting relaying signals from selected the generator model. From simulation results, the loss of excitation algorithm can be used to field protection for generator.

지능형기법을 이용한 변압기의 디지털 차동보호 (Digital Differential Protection of Transformer using Intelligent Schemes)

  • 박철원;정호성;신명철;이복구;서희석;윤석무;이춘모
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 하계학술대회 논문집 G
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    • pp.2281-2283
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    • 1998
  • In this paper, we propose a digital differential protection of power transformer using intelligent schemes. Intelligent schemes is based on fuzzy logic and neural networks. To enhance the distinction between fault and inrush of conventional approaches, relaying technique by fuzzy logic and neural networks are used. We used transformer inrush currents, external and internal fault signals, which are obtained from EMTP simulation.

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신경회로망에 의한 변압기의 여자돌입과 내부고장 판별에 관한 연구 (A Study on the Discriminate between Magnetizing Inrush and Internal Faults of Power Transformer by Artificial Neural Network)

  • 박철원;조필훈;신명철;윤석무
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 하계학술대회 논문집 B
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    • pp.606-609
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    • 1995
  • This paper presents discriminate between magnetizing inrush and internal faults of power transformer by artificial neural networks trained with preprocessing of fault discriminant. The proposed neural networks contain multi-layer perceptron using back-propagation learning algorithm with logistic sigmoid activation function. For this training and test, we used the relaying signals obtained from the EMTP simulation of model power system. It is shown that the proposed transformer protection system by neural networks never misoperated.

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발전기의 불평형 검출을 위한 디지털 역상 계전 알고리즘 (Digital Negative Sequence Relay Algorithm for Detection of Unbalanced State in a Generator)

  • 박철원
    • 전기학회논문지P
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    • 제62권4호
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    • pp.198-203
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    • 2013
  • There are conditions that can be unbalanced three phase currents in a large generator by untransposed lines, unbalanced loads, unsymmetrical faults, and open phases. The unbalanced conditions can producing negative sequence components of current that induce two times frequence current in the surface of the rotor, the retaining rings, the slot wedges in the field windings. These rotor currents make the rotor rapidly overheat, so the rotor can cause substantial damage in a very short time. This paper presents the digital negative sequence relay algorithm for unbalanced protection in a generator. The proposed algorithm was tested by using collected current signals on PSCAD/EMTDC considering a hydro turbine based generator control system. It can be seen that the proposed relaying by negative sequence current is useful for detection of unbalanced state of large generator.