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Dissertations / Theses on the topic 'Frequency relay'

Author: Grafiati

Published: 4 June 2021

Last updated: 10 February 2022

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1

Lang, Ke. "Toward optimal cooperative sensing and cooperative relay in cognitive radio networks /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?ECED%202010%20LANG.

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2

Zhang, Shunqing. "Cooperative relay in the next generation wireless networks /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20ZHANGS.

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3

Schedler, Stephan [Verfasser]. "Generalized Frequency Division Multiplexing in the Two-Way-Relay Channel / Stephan Schedler." Aachen : Shaker, 2016. http://d-nb.info/1120863880/34.

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4

St, Germain Kenneth W. "Shipboard radio frequency and free space optics communications system using an airborne relay." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FStGermain.pdf.

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5

Eddaghel, Masoud. "Mitigating PAPR in cooperative wireless networks with frequency selective channels and relay selection." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16339.

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The focus of this thesis is peak-to-average power ratio (PAPR) reduction in cooperative wireless networks which exploit orthogonal frequency division multiplexing in transmission. To reduce the PAPR clipping is employed at the source node. The first contribution focuses upon an amplify-and-forward (AF) type network with four relay nodes which exploits distributed closed loop extended orthogonal space frequency block coding to improve end-to-end performance. Oversampling and filtering are used at the source node to reduce out-of-band interference and the iterative amplitude reconstruction decod

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6

Ma, Jun. "Channel estimation and signal detection for wireless relay." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37082.

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Wireless relay can be utilized to extend signal coverage, achieve spatial diversity by user cooperation, or shield mobile terminals from adverse channel conditions over the direct link. In a two-hop multi-input-multi-output (MIMO) amplify-and-forward (AF) relay system, the overall noise at the destination station (DS) consists of the colored noise forwarded from the relay station (RS) and the local white noise. We propose blind noise correlation estimation at the DS by utilizing statistics of the broadband relay channel over the RS-DS hop, which effectively improves signal detection at the DS.

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7

Ghafari, Christophe. "Innovative numerical protection relay design on the basis of sampled measured values for smartgrids." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT113/document.

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Avec le paradigme du réseau intelligent, les ingénieurs de protection ont maintenant à leur disposition une large gamme de nouvelles technologies de communication. Parmi elles, la norme CEI 61850-9-2 a introduit le concept de bus de procédé qui permet l'envoi de valeurs échantillonnées horodatées à un temps absolu depuis les transformateurs de mesure du terrain jusqu’aux relais de protection numériques. Ces derniers peuvent intégrer la fonction d'unité de mesure de phaseur qui peut être utilisé pour échanger des synchrophaseurs entre les fonctions de protection et pour une nouvelle protection

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8

Motter, Daniel. "Modelagem computacional de funções de proteção baseadas em medidas de frequência para detecção de ilhamento de geração distribuída." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-14032014-083240/.

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O ilhamento em sistemas elétricos contendo geração distribuída ocorre quando parte da rede elétrica torna-se eletricamente isolada da concessionária e o subsistema isolado continua a ser energizado por geradores distribuídos. É importante detectar essa condição, que pode, por exemplo, levar a problemas como alteração da qualidade da energia elétrica e religamento automático fora de sincronismo, causando danos irreversíveis aos equipamentos da rede elétrica. Uma forma de detecção do ilhamento é o uso de funções de proteção de frequência e suas variações, tais como a função de taxa de variação d

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9

Mahmud, Azwan Bin. "Enhancing capacity and coverage for heterogeneous cellular systems." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/enhancing-capacity-and-coverage-for-heterogeneous-cellular-systems(bdacd285-1afa-498a-a2fa-abb7fad84d00).html.

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The thesis is concerned with capacity and coverage enhancement of OFDMA heterogeneous cellular systems with a specific focus on fractional frequency reuse (FFR), femtocells and amplify-and-forward (AF) relay systems. The main aim of the thesis is to develop new mathematical analysis for the spectral efficiency and outage probability of multi-cells multi-tier systems in diverse traffic, interference and fading scenarios. In the first part of the thesis, a new unified mathematical framework for performance analysis of FFR and soft frequency reuse (SFR) schemes is developed. This leads to new exa

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Ho, Zuleita, Eduard Jorswieck, and Sabrina Engelmann. "Information Leakage Neutralization for the Multi-Antenna Non-Regenerative Relay-Assisted Multi-Carrier Interference Channel." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-121245.

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In heterogeneous dense networks where spectrum is shared, users' privacy remains one of the major challenges. On a multi-antenna relay-assisted multi-carrier interference channel, each user shares the spectral and spatial resources with all other users. When the receivers are not only interested in their own signals but also in eavesdropping other users' signals, the cross talk on the spectral and spatial channels becomes information leakage. In this paper, we propose a novel secrecy rate enhancing relay strategy that utilizes both spectral and spatial resources, termed as information leakage

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11

Souza, Silvio Aparecido de. "Algoritmos genéticos aplicados à proteção e estimação de harmônicos em sistemas elétricos de potência." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-17032009-150821/.

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O objetivo de um sistema elétrico de potência é gerar energia elétrica e fornecer continuamente esta energia aos usuários finais dentro de padrões de qualidade aceitáveis. Neste contexto, diferentes aplicações usando algoritmos genéticos (AGs) para resolver problemas relacionados a sistemas elétricos de potência são apresentadas neste trabalho. A estimação de harmônicos, estudos relativos aos relés de freqüência e aplicações da proteção de distância são os assuntos investigados nesta tese. Para análise harmônica foram consideradas freqüências em sistemas de potência de até a vigésima quinta or

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12

Nguyen, Hai Dang. "Déploiement et ordonnancement dans Wimax avec relais : IEEE802.16j." Phd thesis, Université d'Evry-Val d'Essonne, 2011. http://tel.archives-ouvertes.fr/tel-00878774.

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Les systèmes cellulaires modiles WiMAX ont pour objectif de fournir des services multimédias à haut débit à n'importe quel moment, n'importe quel endroit avec un prix abordable. La combinaison d'orthogonale accès multiples (OFDMA) et le relais en Wimax donnent plusieurs opportunités pour des réseaux moins coûteux et plus performances. La norme Wimax 802.16j élargit non seulement la couverture de la cellule, mais aussi augmente le débit moyen des utilisateurs. Plusieurs recherches de cette norme ont été publiées afin d'optimiser la performance du réseau. Cependant, lorsque nous étudions les arc

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Vargas, Elis Tápia. "Uma proposta de relé digital de freqüência baseado em algoritmos genéticos." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-17112006-112206/.

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Este trabalho apresenta um método baseado em algoritmos genéticos AGs, o qual consiste na estimação dos parâmetros associados as formas de ondas, tais como amplitude, freqüência e ângulo de fase das mesmas, referentes a uma proposição de relé de freqüência. O método proposto é baseado em algoritmos genéticos com representação real, tendo em vista a não necessidade de codificação dos valores logo na entrada do processo. O objetivo do trabalho é apresentar um estudo de uma das várias técnicas da computação evolutiva, conhecida como AG, cuja aplicação é inspirada nos mecanismos da evolução natu

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CAMPOS, Alana Kelly Xavier Santos. "Um novo método de estimação fasorial para uso em relés digitais de proteção." Universidade Federal de Campina Grande, 2016. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/582.

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Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-05-04T19:00:50Z No. of bitstreams: 1 ALANA KELLY XAVIER SANTOS CAMPOS – TESE (PPGEE) 2016.pdf: 5517354 bytes, checksum: 24306600f8b9a28a2d230c48b0811a3a (MD5)<br>Made available in DSpace on 2018-05-04T19:00:50Z (GMT). No. of bitstreams: 1 ALANA KELLY XAVIER SANTOS CAMPOS – TESE (PPGEE) 2016.pdf: 5517354 bytes, checksum: 24306600f8b9a28a2d230c48b0811a3a (MD5) Previous issue date: 2016-10-21<br>Capes<br>Um método de estimação fasorial é proposto para ser utilizado em relés digitais de proteção. Este método tem o

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15

Ferreira, André Mariano Silva. "Frequency characterization of single coil RF relays." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/18519.

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Mestrado em Engenharia Electrónica e Telecomunicações<br>Short-Open-Load-Thru (SOLT) e Thru-Re ect-Line (TRL) são as duas técnicas de calibração mais utilizadas na correcção de erros aplicada em Vector Network Analyzers (VNA). No entanto, alguns requisitos têm que ser cumpridos, de modo a permitir a aplicação destas técnicas de calibração em medições realizadas em placas de teste. Esta dissertação destina-se a caracterização em frequência de dispositivos inseridos em placas de teste, mais especificamente de relés electromecânicos de bobina única para aplicações em frequências rádio (R

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16

Kopecký, Jan. "Řídicí obvody kolejového výtahu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413058.

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This master thesis deals with the mechanical and electrical design of the drive of the inclined construction lift. Individual components are selected in the design. Furthermore, a theoretical research is carried out regarding wireless modules and logic controllers. The selection of sensors is made and the method of retrieving signals from sensors and converting them into iputs the control circuits is also outlined. A program is written in Arduino IDE that wirelessly controls the motion of a motor via variable frequency drive.

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17

Harrison, Robert Anthony. "An electromagnetic field model for the design of RF reed relays." Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/2678.

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A model of the electromechanical characteristics, electrostatic characteristics and coil eddy current losses of a reed relay was developed. These characteristics were returned from reed and coil dimensions. The model was intended as an aid to the design of reed relays for Radio Frequency (RF) and high voltage applications. An electromechanical model of a reed switch and coil was developed using a combination of an axisymmetric finite element model and analytical methods. The characteristics returned from this model were operate, release and differential amp turns, contact gap and contact force

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18

Ceja, Gómez Frida. "Setting under-frequency relays in power systems via integer programming." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104711.

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The deviation of the frequency of a power system from its nominal value is a reflection of the mismatch between generation and load. Such deviations are serious and must be monitored and controlled very closely. One major impact of operating outside a narrow range around the nominal frequency is that generators can be damaged. To avoid this, manufacturers set time interval limits for under-frequency operation and when such limits are exceeded, the generator trips. However, unless generator tripping is coordinated with some accompanying load shedding, the system inability to supply its load can

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19

Podolan, Luděk. "Jednoúčelový stroj zajišťující lisování kanystrových nálevek." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221101.

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The aim of this diploma thesis is detail description of theory, design process and final realization of single-purpose machine for pressing canister funnels. Theoretical section of this work covers manufacturing standards of the electrical cabinets, options for the single-purpose machine control with focus on the programmable logic controller e.g. PLC, PLC control program concept with definition of the main alarm states and description of two types of electrical cabinet. Practical part contains description of the electrical cabinet, its block diagram, photo documentation of the wiring (chapter

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20

Osborn, Christopher Eric. "Protection, Automation, and Frequency Stability Analysis of a Laboratory Microgrid System." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1828.

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Due to increasing changes in the power industry, Cal Poly San Luis Obispo's electrical engineering department introduced a set of initiatives to adequately equip students with the skills and knowledge to interact with new technologies. Specifically, the department proposed a microgrid and power systems protection and automation laboratory to strengthen students' knowledge of microprocessor-based relays. This paper outlines a microgrid laboratory system that fulfills the initiative's goal and proposes a collection of laboratory experiments for inclusion in a new laboratory course at Cal Poly. T

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21

Ghandour-Haidar, Soukayna. "Estimation de canal à évanouissements plats dans les transmissions sans fils à relais multibonds." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT102.

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Cette thèse traite de l'estimation d'un canal de communication radio-mobile multi-bond. La communication entre l'émetteur et le récepteur est ainsi faite par l'intermédiaire de relais (de type « Amplify and-Forward ») en série. Les différents éléments (émetteurs, relais, récepteurs) peuvent être fixes ou mobiles. Chaque lien de communication (chaque bond) est modélisé par un canal de Rayleigh à évanouissements plats, avec un spectre Doppler issu de deux environnements possibles de diffusion : en deux dimensions (2D, amenant le spectre en U de Jakes), ou en trois dimensions (3D, amenant un spec

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22

Galzerano, Leandro. "Estabelecimento de pastagens de tifton 85 sob doses de aduba??o nitrogenada." Universidade Federal Rural do Rio de Janeiro, 2008. https://tede.ufrrj.br/jspui/handle/tede/577.

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Made available in DSpace on 2016-04-28T14:59:45Z (GMT). No. of bitstreams: 1 2008 - Leandro Galzerano.pdf: 1398173 bytes, checksum: 3b9bc8540a1e5f744b54fffefe6a7828 (MD5) Previous issue date: 2008-08-05<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior<br>This work was carried out in order to obtain subsidies under the definition of strategies for nitrogen fertilization of pastures of tifton 85, based on monitoring the dynamics changes in the structure of swards. The underlying assumption was that the application of increasing levels of N is a powerful tool for that purpose. The

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23

Syu, Ting-wei, and 許庭維. "Adaptive under-frequency load shedding relay using load frequency sensitivity and frequency variation rate." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/6xd4tc.

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碩士<br>國立中正大學<br>電機工程所<br>96<br>There are many ways maintain power system stability, for example exciter, governor, automatic generation control (AGC), under-load tap changing transformer (ULTC), flexible AC transmission system(FACTS) and so on. But these methods can only be used for certain disturbances. If major incidents occur in the power system, the abovementioned methods may not be effectively to stabilize the system. To maintain the operation of power system, load shedding would have to be executed to drop off the load buses. Under-frequency load shedding(UFLS), which has been worldwidel

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24

Kwan, Donny H. W. "A computer algorithm for implementing a frequency relay." 1991. http://hdl.handle.net/1993/17328.

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25

"Iterative receiver in multiuser relaying systems with fast frequency-hopping modulation." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-08-1199.

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In this thesis, a novel iterative receiver and its improved version are proposed for relay-assisted multiuser communications, in which multiple users transmit to a destination with the help of a relay and using fast frequency-hopping modulation. Each user employs a channel encoder to protect its information and facilitate interference cancellation at the receiver. The signal received at the relay is either amplified, or partially decoded with a simple energy detector, before being forwarded to the destination. Under flat Rayleigh fading channels, the receiver at the destination can be implemen

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26

Chen, Ying-Tsuen, and 陳盈村. "Layered Video Multicast Using Fractional Frequency Reuse over Wireless Relay Networks." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/15540078543699047488.

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碩士<br>國立中山大學<br>資訊工程學系研究所<br>100<br>Multimedia services over wireless networks are getting popular. With multicast many mobile stations can join the same video multicast group and share the same radio resource to increase frequency utilization efficiently. However users may locate at different positions so as to suffer different path loss, interference and receive different signal to interference and noise ratio (SINR). Users at the cell-edge receiving lower SINR may degrade the multicast efficiency. In this thesis we propose four schemes considering fractional frequency reuse (FFR) over relay

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Hsiao, Ming-Chun, and 蕭名鈞. "Parameter Design of Under-frequency Relay for Microgrid Using Genetic Programming." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/03989239011024702364.

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碩士<br>中原大學<br>電機工程研究所<br>100<br>In this thesis, the parameters of the under-frequency relay are designed for a microgrid power system. The unnecessary load shedding can be avoided once the power system is subject to severe disturbances, e.g., generator tripping. The NEPLAN V5.5.0 software package was used to set up the microgrid power system. The power flow and the transient stability analysis were conducted considering distributed generations (DGs) trippings. The optimal parameters of the under-frequency relay are obtained using Genetic Programming and penalty function. The tripping pr

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Lai, Hsin-Hung, and 賴信宏. "Multi-Decision Handover Mechanism for Fractional Frequency Reuse in Relay Networks." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/17792021428764940202.

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碩士<br>國立中山大學<br>資訊工程學系研究所<br>101<br>With the popularity of wireless networks, it needs to support user’s mobility cross different base stations, hence, the handover mechanism becomes an important issue. When the user frequently moves between two cells, it will occur the Ping-Pong effect that increases the delay time and reduces the efficiency of system. In this thesis, we proposed a new handover mechanism by considering the fractional frequency reuse (FFR) over relay networks to reuse frequency in multi-cells. The proposed method can reduce the unnecessary handover caused by the interference i

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Chou, Wen-Yang, and 周文揚. "Carrier Frequency Offset Estimation for a Simple Space-Time OFDM Based Relay Networks." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/23690782255068485901.

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碩士<br>國立臺灣大學<br>電信工程學研究所<br>100<br>The well known advantages of orthogonal frequency division multiplexing (OFDM) in combating inter symbol interference (ISI) and frequency selective fading channels have led wireless relay networks to use OFDM for data transmission. However,it is well known that OFDM systems are sensitive to carrier frequency o set(CFO). The performance of these wireless relay networks degrades signi cantly when there is CFO. In this thesis, we study CFO estimation for a simple Space-Time OFDM scheme for relay networks. First, We derive an explicit expression of the correlatio

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"Transmission Strategies for Two-Way Relay Channels." Doctoral diss., 2015. http://hdl.handle.net/2286/R.I.36464.

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abstract: The recent proposal of two-way relaying has attracted much attention due to its promising features for many practical scenarios. Hereby, two users communicate simultaneously in both directions to exchange their messages with the help of a relay node. This doctoral study investigates various aspects of two-way relaying. Specifically, the issue of asynchronism, lack of channel knowledge, transmission of correlated sources and multi-way relaying techniques involving multiple users are explored. With the motivation of developing enabling techniques for two-way relay (TWR) channels exp

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Lai, Yong-Zhen, and 賴勇禎. "Reliability Analysis and Parameter Design of Under-frequency Relay in Mircogrid Using Immune Algorithms." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/33232596496625618722.

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碩士<br>中原大學<br>電機工程研究所<br>101<br>Abstract In this thesis, the parameters of the under-frequency relay are designed and the number of batteries is estimated for a microgrid power system. The unnecessary load shedding can be avoided once the power system is subject to severe disturbances, e.g., generator tripping. This thesis also applies the customer-oriented indices to analyze the reliability. Preliminary simulation results reveal that the outage time can be reduced and the reliabilities for the system can be improved by including the storage batteries. The NEPLANE V5.5.0 software package was u

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Ruan, Ting-Liang, and 阮庭亮. "Carrier Frequency Offset Estimation Bounds with channel Estimation error for OFDM-based Relay Networks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/kew24n.

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碩士<br>國立東華大學<br>電機工程學系<br>102<br>Cooperative relay network system in which future mobile communication system plays an important role. The orthogonal frequency division multiplexing technology can provide higher transmission rates and resistance multipath channel fading. However, the carrier frequency offset will cause the orthogonal frequency division multiplexing signals orthogonality damage and reduce system performance. Therefore, this paper will focus on applied orthogonal frequency division multiplexing system relay network with a carrier frequency of the channel estimation error under t

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Syu, Bo-Han, and 許博涵. "Carrier Frequency Offset Estimation Bounds with Unknown Channel Parameters for OFDM-based Relay Networks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/asve7p.

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碩士<br>國立東華大學<br>電機工程學系<br>102<br>With the rapid growth of wireless transmission services, the next generation of wireless communication systems need to provide higher transmission rates and better communication quality. The system has a cooperative relay network communication technology can achieve the quality and efficiency of transport in the future mobile communication systems which play an important role. And the carrier frequency offset estimation in the relay network system is an important research topic. Therefore, this paper will focus on orthogonal frequency division multiplexing

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Lu, Yuan-Chieh, and 呂元介. "Carrier Frequency Offest Estimation Bounds with Channel Estimation Error for OFDM Multi-Relay Systems." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vn8pre.

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碩士<br>國立東華大學<br>電機工程學系<br>105<br>With increasingly high demand for communication and transmission, the cooperative relay network system can contribute to high-speed, high-volume and high-quality requirements, and not only can Orthogonal Frequency Division technology improve the transmission rate, but it also can resist the multi-path channel attenuation. Because of the orthogonality of the signal, however, the orthogonal frequency multiplier will degrade the system performance. Hence, this thesis is dedicated to the application in the orthogonal frequency division multiplexing multiple relay s

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Lee, Jian-Hong, and 李建泓. "On the performance Analysis of carrier frequency offset estimation for OFDM-based Relay Networks." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/8vm23y.

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碩士<br>國立東華大學<br>電機工程學系<br>100<br>Cooperative communication which utilizes multiple distributed terminals to transmit data is a promising technology to achieve the high data rate and the better signal quality in the future wireless communication. A relay network with the cooperative communication technology has been shown to effectively increase the throughput and resist the signal fading. In practical, however, the system performance of the relay network would degrade in the presence of the frequency offsets generated by the different terminals. Therefore, it is important to study the frequenc

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Zhou, Jianwei. "Robust Beamforming for OFDM Modulated Two-Way MIMO Relay Network." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-05-11141.

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This thesis studies a two-way relay network (TWRN), which consists of two single antenna source nodes and a multi-antenna relay node. The source nodes exchange information via the assistance of the relay node in the middle. The relay scheme in this TWRN is amplify-and-forward (AF) based analog network coding (ANC). A robust beamforming matrix optimization algorithm is presented here with the objective to minimize the transmit power at the relay node under given signal to interference and noise ratio (SINR) requirements of source nodes. This problem is first formulated as a non-convex optimiza

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Hsing-TaiWu and 吳幸黛. "A High Capacity Cell Architecture Based on Alamouti Coded Relay Strategy and Frequency Allocation Scheme." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/62151314306861490093.

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碩士<br>國立成功大學<br>電腦與通信工程研究所<br>98<br>In the orthogonal frequency division multiple access (OFDMA) system, how to eliminate the inter cell interference (ICI) problem is the key to providing ubiquitously high data rate services. In the recent years, the novel frequency allocation scheme (FAS) and effcient relay strategy has become two popular techniques to solve this problem. In this thesis, we combine these two techniques to build a high-capacity cell architecture. Firstly, each of the inner and outer zone areas within a sector is allocated a portion of bandwidth, i.e. 2/3 and 1/3, respectively,

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Hsu, Guo-Wei, and 徐國瑋. "A Study on the Carrier Frequency Offset Estimation Methods for the OFDM-based Relay Networks." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/12247490096206765375.

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碩士<br>國立東華大學<br>電機工程學系<br>101<br>In this research, relay network’s excellent property is used to level up system efficiency and signal quality. Affected by frequency error and Doppler shift, carrier frequency offset (CFO) happens. Therefore, improving this disadvantage is the main purpose in this research; besides, it was based on Orthogonal Frequency-Division Multiplexing (OFDM) Function Modulation to analyze a certain relay network. Maximum Likelihood Estimation (MLE) was proposed to deal with carrier frequency offset; data were acquired through computer simulation. Various system parameters

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Babi, Bombay. "Setting frequency relays and voltage relays to protect synchronous distributed generators against islanding and abnormal frequencies and voltages." Diss., 2015. http://hdl.handle.net/10500/20705.

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This study concerns frequency relays and voltage relays applied to the protection of synchronous distributed generators operating in reactive power control mode without a frequency regulation function. The effect of active and reactive powers combination, load power factor, and reactive power imbalance are investigated for their implication for the anti-islanding setting of the frequency relay. Results reveal that the effect of these factors must be considered when setting the relay for islanding detection. For the voltage relay, results reveal that the effect of active and reactive powe

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"Signal detection and equalization in cooperative communication systems having multiple carrier frequency offsets." Thesis, 2009. http://library.cuhk.edu.hk/record=b6074753.

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Different from multiple-input multiple-output (MIMO) systems, a major challenge for cooperative communications is the problem of synchronization because multiple transmissions undertaken by cooperative systems may not be synchronized in time and/or frequency. With synchronization errors, conventional space-time (ST) codes may not be directly applicable any longer. To tackle the problem of timing synchronization, space-frequency (SF) coded orthogonal frequency division multiplexing (OFDM) cooperative systems have recently been proposed to achieve asynchronous diversity due to their insensitivit

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Wu, Meng-Hsueh, and 吳孟學. "Analysis and Simulation of the Carrier Frequency Offset Estimation Bounds for OFDM-based Multi-Relay Systems." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/59524983792048204085.

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碩士<br>國立東華大學<br>電機工程學系<br>103<br>In recent years, demand for wireless transmission services is growing rapidly, so faster transfer speed and good signal quality are now very important issues. In order to increase the transmission capacity and improve system performance of wireless networks, a plurality of input and output Multiple Input Multiple Output (MIMO) system using multiple antennas can inhibit the weak passage and efficiency increase the spectral efficiency of a wireless communication system. But the implementation is not easy because of the device with limited terrain, therefore the r

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Tang, Taiwen. "Multiple antenna downlink: feedback reduction, interference suppression and relay transmission." Thesis, 2006. http://hdl.handle.net/2152/2970.

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CHEN, PO-HSUAN, and 陳柏亘. "Parameter Design of Low-frequency Relay for Power System with Fuzzy Loads Using Variable-Strings-based Genetic Algorithms." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/3458cd.

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碩士<br>中原大學<br>電機工程研究所<br>98<br>In this thesis, the parameters of the low-frequency relay are designed for a small independent power system. The unnecessary load shedding can be avoided once the power system is subject to severe disturbances, e.g., generator tripping. The NEPLANE V5.4.3 software package was used to set up the small independent power system. The power flow and the transient stability analysis were conducted considering severe generator trippings. The optimal parameters of the low-frequency relay are obtained using variable string Genetic Algorithms and penalty function. The t

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Chen, Po-An, and 陳柏安. "Joint Time Synchronization and Carrier Frequency Offset Estimation for OFDM-Based Two-Way Amplify-and-Forward Relay Systems." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69702794028021445191.

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碩士<br>國立清華大學<br>通訊工程研究所<br>102<br>In this thesis, we propose a joint time synchronization and carrier frequency offset (CFO) estimation scheme using partial Zadoff-Chu sequences for orthogonal frequency-division multiplexing (OFDM)-based two-way amplify-and-forward (AF) relay systems. In the preamble design, the training signals for the two terminals are not only separated in the frequency domain but also isolated in the time domain so as to limit their mutual interference in both domains. Such a preamble structure allows joint estimation of timing delays and CFOs and, to the best of our knowl

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Chang, Chia-Yu, and 張家毓. "On Time Synchronization, Carrier Frequency Offset Estimation, and Channel Estimation for OFDM-Based Two-Way Amplify-and-Forward Relay Systems." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/63161735250964401589.

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碩士<br>國立清華大學<br>通訊工程研究所<br>103<br>In this thesis, a novel preamble structure of two time-domain training signals is proposed for time synchronization, carrier frequency offset (CFO) estimation, and channel estimation in orthogonal frequency-division multiplexing (OFDM)-based two-way amplify-and-forward (AF) relay systems. The first training signal consists of a specific complex sequence with a nice property that the Hadamard product of the sequence and its complex-conjugate circular-shift version (excluding the zero-shift case) is a near-perfect sequence. The second training signal is a sequen

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MEHRPOUYAN, HANI. "Estimation and Effects of Imperfect System Parameters on the Performance of Multi-Relay Cooperative Communications Systems." Thesis, 2010. http://hdl.handle.net/1974/7475.

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To date the majority of research in the area of cooperative communications focuses on maximizing throughput and reliability while assuming perfect channel state information (CSI) and synchronization. This thesis, seeks to address performance enhancement and system parameter estimation in cooperative networks while relaxing these idealized assumptions. In Chapter 3 the thesis mainly focuses on training-based channel estimation in multi-relay cooperative networks. Channel estimators that are capable of determining the overall channel gains from source to destination antennas are derived. Next,

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Rajan, G. Susinder. "Low Decoding Complexity Space-Time Block Codes For Point To Point MIMO Systems And Relay Networks." Thesis, 2008. http://hdl.handle.net/2005/742.

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It is well known that communication using multiple antennas provides high data rate and reliability. Coding across space and time is necessary to fully exploit the gains offered by multiple input multiple output (MIMO) systems. One such popular method of coding for MIMO systems is space-time block coding. In applications where the terminals do not have enough physical space to mount multiple antennas, relaying or cooperation between multiple single antenna terminals can help achieve spatial diversity in such scenarios as well. Relaying techniques can also help improve the range and reliability

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Dutta, Amit Kumar. "Transceiver Design Based on the Minimum-Error-Probability Framework for Wireless Communication Systems." Thesis, 2015. http://etd.iisc.ernet.in/2005/3732.

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Parameter estimation and signal detection are the two key components of a wireless communication system. They directly impact the bit-error-ratio (BER) performance of the system. Several criteria have been successfully applied for parameter estimation and signal detection. They include maximum likelihood (ML), maximum a-posteriori probability (MAP), least square (LS) and minimum mean square error (MMSE) etc. In the linear detection framework, linear MMSE (LMMSE) and LS are the most popular ones. Nevertheless, these criteria do not necessarily minimize the BER, which is one of the key aspect of

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Chiu, Sung-En, and 邱頌恩. "Maximum Achievable Diversity of Noncoherent Space-Frequency Coded Systems with Decode-and-Forward Relays." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/55193327483220843959.

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碩士<br>國立交通大學<br>電子研究所<br>98<br>In this thesis, we conduct the analysis of noncoherent cooperative space-frequency coded (SFC) systems operating under the decode-and-forward (DAF) protocol in a two-hop relaying network, where neither the transmitter nor the receiver knows the channel. We assume practically that each of the intermediate relay nodes may fail to decode the message from the source. Each relay use an error detection method to determine whether or not it has reliably decoded the message, and only those relays who think they decode successfully will forward the message to the destinat

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Wu, Shing-You, and 吳星佑. "Carry Frequency Offset Estimation Bounds For OFDM-based Multi-Relays Network Over Multipath Fading Channel." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/35008777336094159624.

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碩士<br>國立東華大學<br>電機工程學系<br>101<br>Cooperative communication technology has been proven to enhance the system. Capacity and plays a key role in the wireless multi-media communication system. A relay network with cooperative communication can effectively increase the throughput and resist the signal fading by its spatial diversity. Therefore, an OFDM-based relay network system will play a key role in the future wireless multimedia communications. . In an OFDM-based relay network, the carrier frequency offset (CFO) would destroy the orthogonality of the OFDM signal and introduce the inter-carrier

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