• 제목/요약/키워드: mRelay

검색결과 219건 처리시간 0.02초

이동 Ad-hoc 네트워크에서의 멀티미디어 서비스 구현 (Implementation of Multimedia Services in a Mobile Ad-hoc Network)

  • 노광현;권혜연;신재욱;박애순
    • 융합신호처리학회논문지
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    • 제7권2호
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    • pp.45-52
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    • 2006
  • 이동 Ad-hoc 네트워크(Mobile Ad-hoc Network)는 자기 조직화, 기반망에 독립적인 네트워크의 특성상 많은 응용 분야를 가지고 있다. 본 논문에서는 mRelay(Multi-hop Relay) 시스템이라고 명명한 MANET을 위한 멀티미디어 응용 서비스 모델을 제안한다. mRelay 시스템은 무선 멀티미디어 통신 기능을 가진 무인 이동체를 mRelay 단말로 사용하여 멀티흡 통신 기반의 인터넷 연동이 가능한 멀티미디어 서비스를 제공한다. 멀티흡 라우팅 프로토콜인 AODV가 수정되어 mRelay 단말에 적용되었고, mRelay 시스템이 실내에서의 다양한 시나리오 상황에서 기반망 도움 없이 이동 Ad-hoc 네트워크를 구성하고 유지하며, 안정적인 멀티흡 멀티미디어 서비스가 가능함을 보였다. mRelay 시스템은 다양한 이동 Ad-hoc 네트워크의 응용 서비스에 활용될 수 있을 것이다.

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Exact Performance Analysis of AF Based Hybrid Satellite-Terrestrial Relay Network with Co-Channel Interference

  • Javed, Umer;He, Di;Liu, Peilin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권9호
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    • pp.3412-3431
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    • 2015
  • This paper considers the effect of co-channel interference on hybrid satellite-terrestrial relay network. In particular, we investigate the problem of amplify-and-forward (AF) relaying in hybrid satellite-terrestrial link, where the relay is interfered by multiple co-channel interferers. The direct link between satellite and terrestrial destination is not available due to masking by surroundings. The destination node can only receive signals from satellite with the assistance of a relay node situated at ground. The satellite-relay link is assumed to follow the shadowed Rice fading, while the channels of interferer-relay and relay-destination links experience Nakagami-m fading. For the considered AF relaying scheme, we first derive the analytical expression for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR). Then, we use the obtained MGF to derive the average symbol error rate (SER) of the considered scenario for M-ary phase shift keying (M-PSK) constellation under these generalized fading channels.

UML(Unified Modeling Language)기법을 이용한 PCM전류차동계전기 정정모듈 개발 (Development of PCM Current Differential Relay Setting Module Using UML)

  • 오태욱;오성민;민병운;이승재;최면송
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.329-331
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    • 2003
  • PROSET2000 that is integrated protective management system had developed and used in order to automate the setting process of protective relays in transmission system protection. PROSET2000 have database for relay setting and automated for relay setting program within. This paper proposed PCM current differential relay setting program point of Object Oriented Programming paradigm using Unified Modeling Language about additional relay in PROSET2000. Nevertheless each relay uses same current differential but setting method is different. This paper discribed different thing about setting method of each relay and evaluated more effective and corrective relay setting program using UML.

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적응형 변조 기법을 이용한 네트워크 부호화 기반 양방향 중계 통신 (Network-Coding Based Two-way Relay Communication Using Adaptive Modulation Sheme)

  • 이진희;공형윤
    • 한국인터넷방송통신학회논문지
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    • 제10권5호
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    • pp.147-151
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    • 2010
  • 논문에서는 양방향 중계기 통신에서 사용자와 중계기의 채널 환경을 기준으로 중계기의 QoS(Quality of Service)를 만족시키도록 하는 적응형 변조 기법을 이용한 네트워크 부호화 기반 양방향 중계기 통신을 제안한다. 양방향 중계기 통신은 두 사용자가 중계기의 도움을 받아 서로의 데이터를 교환하는 통신 방식이다. 네트워크 부호화를 이용한 양방향 중계기 통신은 기존의 양방향 통신에 비해 데이터 전송에 필요한 시간을 줄임으로써 높은 처리량(throughput)을 얻을 수 있다. 본 논문에서는 사용자와 중계기간의 채널 환경를 기준으로 M-QAM(Quadrature Amplitude Modulation) 변조 기법을 이용하여 시스템의 QoS를 만족시키는 적응형 변조 방법을 제안한다. 모의 실험을 통해 제안한 방식이 시스템이 원하는 QoS를 만족시킴을 보인다.

Degrees of Freedom of 3-user MIMO Interference Channels with Instantaneous Relay Using Interference Alignment

  • Qiang, Wang;Yuquan, Shu;Minhua, Dong;Ji, Xu;Xiaofeng, Tao
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권5호
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    • pp.1624-1641
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    • 2015
  • Instantaneous relay (relay-without-delay) using interference alignment is a promising approach to neutralizing interference and improving system capacity. In Wang Chenwei's work, a 2-user scenario required both source and relay to access the global channel state information (CSI). This paper shows a new method of interference alignment improves the degrees of freedom (DoF) prominently for the 3-user MIMO interference channel with instantaneous relay. This new method is focused on the relay node that completes the alignment interference neutralization so the global CSI is obtained only once and the pressure on the base station can be mitigated. In addition, the 3-user MIMO interference channels with instantaneous relay can achieve 2M DoF when source and destination have M antennas, respectively. This method shows 33% improvement over the conventional method using interference alignment which obtains 3M/2 DoF.

M/W대역 디지털 방송중계용 FPU 무선전송 시스템 분석과 시뮬레이터 설계 (Analysis and Simulator Design of Portable Microwave Digital FPU Transmission System)

  • 강희조;조성언;최용석
    • 한국정보통신학회논문지
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    • 제7권4호
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    • pp.658-666
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    • 2003
  • 본 논문에서는 M/W 디지털 방송중계용 주파수의 공유방안에 관한 연구의 기초단계로서 AWGN 채널 환경에서 M/W 디지털 방송중계용 FPU(Field Pick Up) 무선전송 시스템 규격 및 특성을 분석하고 시뮬레이터 설계를 통하여 시스템 성능을 분석하였다. 국내 방송 중계용의 경우 디지털화 진행이 추진되고 있는바 향후 M/W 방송중계용 주파수 재배치를 위한 간섭평가 및 국내 방송중계용 표준화에 대한 기초 자료로 활용하고자 한다.

Exact and Approximate Symbol Error Probability of cooperative systems with best relay selection and all participating relaying using Amplify and Forward or Decode and Forward Relaying over Nakagami-m fading channels

  • Halima, Nadhir Ben;Boujemaa, Hatem
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권1호
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    • pp.81-108
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    • 2018
  • In this paper, we derive the theoretical Symbol Error Probability (SEP) of cooperative systems with best relay selection for Nakagami-m fading channels. For Amplify and Forward (AF) relaying, the selected relay offers the best instantaneous Signal to Noise Ratio (SNR) of the relaying link (source-relay-destination). In cooperative networks using Decode and Forward (DF), the selected relay offers the best instantaneous SNR of the link between the relay and the destination among the relays that have correctly decoded the transmitted information by the source. In the second part of the paper, we derive the SEP when all participating AF and DF relaying is performed. In the last part of the paper, we extend our results to cognitive radio networks where there is interference constraints : only relays that generate interference to primary receiver lower than a predefined threshold T can transmit. Both AF and DF relaying with and without relay selection are considered.

계통변화를 고려한 자율 적응형 과전류 계전기 (Autonomous Adaptive Digital Over Current Relay)

  • 윤준석;이승재;최면송;강상희;김상태;임성일;오성민;김지균;박성준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 A
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    • pp.6-8
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    • 2002
  • In this paper present Autonomous Adaptive Digital Over Current Relay which acts autonomous setting using voltage and current measured by relay in the change of power systems. Automation of relay setting is required for distribution automation although manual relay setting is used at present. This paper presents Autonomous Relay Setting which knows change of the power system and acquires setting element using the Recursive Least Squares. Relay setting is very difficult work. But proposed relay is expected to decrease burden of relay setting using acquired information of power system change and autonomous setting. Also fast protective ability is expected according to change of power system.

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Performance Analysis of Nonlinear Energy-Harvesting DF Relay System in Interference-Limited Nakagami-m Fading Environment

  • Cvetkovic, Aleksandra;Blagojevic, Vesna;Ivanis, Predrag
    • ETRI Journal
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    • 제39권6호
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    • pp.803-812
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    • 2017
  • A decode-and-forward system with an energy-harvesting relay is analyzed for the case when an arbitrary number of independent interference signals affect the communication at both the relay and the destination nodes. The scenario in which the relay harvests energy from both the source and interference signals using a time switching scheme is analyzed. The analysis is performed for the interference-limited Nakagami-m fading environment, assuming a realistic nonlinearity for the electronic devices. The closed-form outage probability expression for the system with a nonlinear energy harvester is derived. An asymptotic expression valid for the case of a simpler linear harvesting model is also provided. The derived analytical results are corroborated by an independent simulation model. The impacts of the saturation threshold power, the energy-harvesting ratio, and the number and power of the interference signals on the system performance are analyzed.

Security Performance Analysis of DF Cooperative Relay Networks over Nakagami-m Fading Channels

  • Zhang, Huan;Lei, Hongjiang;Ansari, Imran Shafique;Pan, Gaofeng;Qaraqe, Khalid A.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권5호
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    • pp.2416-2432
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    • 2017
  • In this paper, we investigate the security performance for cooperative networks over Nakagami-m fading channels. Based on whether the channel state information (CSI) of wiretap link is available or not, optimal relay selection (ORS) and suboptimal relay selection (SRS) schemes are considered. Also, multiple relays combining (MRC) scheme is considered for comparison purpose. The exact and asymptotic closed-form expressions for secrecy outage probability (SOP) are derived and simulations are presented to validate the accuracy of our proposed analytical results. The numerical results illustrate that the ORS is the best scheme and SRS scheme is better than MRC scheme in some special scenarios such as when the destination is far away from the relays. Furthermore, through asymptotic analysis, we obtain the closed-form expressions for the secrecy diversity order and secrecy array gain for the three different selection schemes. The secrecy diversity order is closely related to the number of relays and fading parameter between relay and destination.