Дисертації з теми "Cooperative relay system"
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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.
Повний текст джерелаLanzarini, Matteo. "Distributed optimization methods for cooperative beamforming in satellite communications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23246/.
Повний текст джерелаÇelebi, Mehmet Bahadır. "On the Improvement of the Capacity of the Heterogeneous Networks with Link-Level and System-Level Approaches." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5353.
Повний текст джерелаWu, Victor Kai Yuen. "OFDM-based cooperative communications in a single path relay network and a multiple path relay network." Thesis, Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11092006-152421/.
Повний текст джерелаDanaee, Ahmad. "Precoder Design for Cooperative MIMO Relay Systems." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1372335578.
Повний текст джерелаAbadi, Tarla. "Design and performance analysis of cooperative relay systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/design-and-performance-analysis-of-cooperative-relay-systems(8edce5bc-1518-4df2-aa49-36bf5386036a).html.
Повний текст джерелаZhang, 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.
Повний текст джерелаHesketh, Thomas John. "Detection and resource allocation algorithms for cooperative MIMO relay systems." Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/6145/.
Повний текст джерелаDuo, Bin. "Polar Coding Schemes for Cooperative Transmission Systems." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14619.
Повний текст джерелаLi, Houmin Thomas Gwynedd A. "Geotextile antenna design for mobile phone cooperative communication relay node." Auburn, Ala., 2008. http://hdl.handle.net/10415/1498.
Повний текст джерелаMallick, Shankhanaad. "Resource optimization in relay based cooperative wireless systems under channel uncertainty." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51485.
Повний текст джерелаApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Shi, Jia. "Cooperation and resource allocation in relay and multicarrier systems." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/378927/.
Повний текст джерелаDai, Gao Yang. "A novel soft forwarding technique for cooperative communication /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?ECED%202010%20DAI.
Повний текст джерелаGu, Jiaqi. "Low-cost interference mitigation and relay processing for cooperative DS-CDMA systems." Thesis, University of York, 2016. http://etheses.whiterose.ac.uk/15577/.
Повний текст джерелаPoulimeneas, Dimitrios. "Back-pressure-like mechanisms on relay selection policies for cooperative diversity systems." Thesis, KTH, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-167794.
Повний текст джерелаOliveira, Pedro Marinho Ramos de. "PARATUCK-N semi-blind receivers for multi-hop cooperative MIMO relay systems." reponame:Repositório Institucional da UFC, 2017. http://www.repositorio.ufc.br/handle/riufc/27317.
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Rejected by Marlene Sousa (mmarlene@ufc.br), reason: Prezado Pedro: Existe uma orientação para que normalizemos as dissertações e teses da UFC, em suas paginas pré-textuais e lista de referencias, pelas regras da ABNT. Por esse motivo, sugerimos consultar o modelo de template, para ajudá-lo nesta tarefa, disponível em: http://www.biblioteca.ufc.br/educacao-de-usuarios/templates/ Vamos agora as correções sempre de acordo com o template: 1. Na capa as informações relativas a hierarquia institucional deve ser em língua portuguesa, Nome da INSTITUIÇÃO; do CENTRO; do DEPARTAMENTO e do PROGRAMA DE PÓS-GRADUAÇÃO. Nesta ordem. Todas as informações devem está em negrito e em caixa alta. Retire a informação Master’s Degree Dissertation e também o nome do estado e o mes. Deixe apenas o nome da cidade e o ano. 2. Na folha de rosto (que segue a capa) Veja o modelo de apresentação das informações de acordo com o template. Apenas o titulo deve ficar em inglês as demais informações são em português. A partir da folha de rosto, todas as outras devem ficar em inglês. Não use negrito nessa folha. Deixe apenas o nome da cidade e o ano. A ficha catalográfica deve vir depois da folha de rosto e as palavras relacionadas aos assuntos devem ser em português. 3. A folha de aprovação naõ deve ter nenhuma informação em negrito. Veja o tamanho da fonte. 4. A dedicatória deve ser depois da folha de aprovação e não é em negrito. 5. A palavra Acknowledgments é em caixa alta, negrito e centralizada na folha. Não use negrito no texto. As folhas prétextuais devem ser contadas mas não são numeradas. Retire numeração. 6. O resumo deve vir antes do Abstract, mesmo quando o trabalho for em língua inglesa. A palavra resumo é em caixa alta, negrito e centralizada na folha. Não use negrito no texto e nem use parágrafos. A palavra abstract é em caixa alta, negrito e centralizada na folha. Não use negrito no texto e nem use parágrafos. 7. As palavras List of Figures, List of Tables, Acronyms, Notation e Sumary são em caixa alta, negrito e centralizada na folha. Não use negrito no texto 8. O sumário está fora dos padrões. Veja uso de maiusculo, minusculo, negrito e itálico nas seções. Não coloque em formato de capítulos e nem coloque as pre-textuais no sumário. Use a palavra referencias e não bibliografia 9. Na lista de referências, Coloque os nomes dos autores entrando pelo sobrenome, seguido do pré nome. Ex. ALMEIDA, A. Se vc optar por abreviar os nomes em toda a lista eles devem ser abreviados. Se vc optar em colocar por extenso em toda e lista deve ficar por extenso para haver uma padronização. Os títulos das publicações devem ser destacadas com o uso do negrito (não use aspas). Com exceção dos artigos de periódicos que devem ser destacados o nome das revistas e não o titulo do artigo. Ao citar os artigos coloque as abreviações v. n. p. e não vol. no e pp. Após essas correções, enviaremos o nada consta por e-mail. Att. Marlene Rocha mmarlene@ufc.br on 2017-09-11T12:55:01Z (GMT)
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Cooperative communication systems is a promising research field nowadays due to its advantages, like the increase of the received power, better quality of signal, and spatial diversity gains. Specifically, multi-hop systems are a very important part of cooperative communications, since they have the advantage of needing less transmission power than the direct systems. Also, multiple-input multiple-output (MIMO) systems are present in several standards of communications, providing some advantages, like the spatial multiplexing gains. Based on this scenario, this work proposes two semi-blind receivers based on the Kronecker product, that jointly estimate the symbol and the channels in a multi-hop Amplify-and-Forward (AF) MIMO relay-assisted system (AF protocol is widely used, due to its great performance and easy implementation). We consider a transmission scheme using a simplified Khatri-Rao space-time (KRST) coding at the source node, combined with an AF scheme at the relay nodes. We show that the third-order tensor of signals received by the destination node satisfies a PARATUCK-(K+1) decomposition, where K is the number of relays. This tensorial modeling enables a semi-blind estimation of symbols and channels with the use of a few pilot symbols. The first receiver called Least-Squares Kronecker-Factorization (LS-KF) is based on a factorization of the Kronecker product matrix between the symbols and the channel matrices. The other receiver called Least-Squares Kronecker-Rearrangement (LS-KR) is based on a rearrangement of this Kronecker product matrix, in order to achieve a rank-1 matrix. The performance of these receivers is evaluated by means of computational simulation results proving their efficiency in estimating the channels and, hence, providing a low Symbol Error Rate (SER). The proposed algorithms in the multi-hop scenario were compared to each other and with the two-hop and three-hop scenarios. The proposed algorithms in the multi-hop scenario were better at all simulations, providing a lower SER and better channels estimations.
Sistemas de comunicações cooperativas são um importante campo de pesquisa atualmente devido às vantagens que oferecem, como o aumento da potência recebida, melhor qualidade de sinal, e ganhos de diversidade espacial. Particularmente, sitemas multi-saltos são uma importante parte das comunicações cooperativas, uma vez que tais sistemas precisam de menos potência de transmissão se comparados a sistemas diretos. Por outro lado, sistemas MIMO (Multiple-Input Multiple-Output) estão presentes em diversos padrões de comunicação, provendo algumas vantagens, como ganhos de multiplexação espacial. Com base nesse cenário, o presente trabalho propõe dois receptores semi-cegos baseados no pro- duto de Kronecker, que estimam conjuntamente os símbolos e os canais de um sistema AF (Amplify- and-Forward) MIMO cooperativo com multiplos saltos (O protocolo AF é bastante usado, devido a sua grande performance e fácil implementação). É considerado um esquema de transmissão usando uma codificação simplificada KRST (Khatri-Rao Space-Time) na fonte, combinada com um esquema AF no relays. É mostrado que o tensor de terceira ordem dos sinais recebidos pelo destino satisfazem uma decomposição tensorial PARATUCK-(K+1), em que K é o número de relays. Esse modelo tensorial permite uma estimação semi-cega dos símbolos e canais, com o uso de alguns símbolos pilotos. O primeiro algoritmo, chamado de Least-Squares Kronecker-Factorization (LS-KF), é baseado em uma fatorização da matrix do produto de Kronecker entre as matrizes de símbolos e canal. Já o outro algoritmo, chamado de Least-Squares Kronecker-Rearrangement (LS-KR), é baseado no re- arranjo dessa matrix do produto de Kronecker, com o objetivo de conseguir uma matrix com rank 1. A performance desses receptores é avaliada através do resultado de simulações computacionais, provando sua eficiência em estimar os canais e prover uma baixa SER (Symbol Error Rate). Os algo- ritmos propostos no cenário multi-hop são comparados um com o outro e com os cenários two-hop e three-hop. Os algoritmos propostos no cenário multi-hop tiveram melhores performance em todas as simulações, resultando numa menor SER e melhores estimações dos canais.
Choi, Gi Wan. "Low-complexity and power-efficient wireless cooperative relay networks with enhanced reliability." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47721.
Повний текст джерелаArab, Loodaricheh Roya. "Resource allocation in wireless systems with relay-based cooperation and energy harvesting." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55917.
Повний текст джерелаApplied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
Jiang, Jing. "Virtual-MIMO systems with compress-and-forward cooperation." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5785.
Повний текст джерелаWang, Hongzheng. "Performance analysis of cooperative systems with spatial random relays and interfering nodes." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B44205041.
Повний текст джерелаAlotaibi, Faisal T. "Distributed space-time block coding in cooperative relay networks with application in cognitive radio." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10965.
Повний текст джерелаAzarian, Yazdi Kambiz. "Outage limited cooperative channels protocols and analysis /." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1154740723.
Повний текст джерелаAdvaita, Advaita, and Mani Meghala Gali. "Performance Analysis of a MIMO Cognitive Cooperative Radio Network with Multiple AF Relays." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13643.
Повний текст джерелаBasharati, Sarhad. "MIMO and Relay Systems Based on Multi-Amplitude Minimum Shift Keying." Thesis, University of Canterbury. Electrical and Computer Engineering, 2013. http://hdl.handle.net/10092/8491.
Повний текст джерелаSousa, Igor FlÃvio SimÃes de. "Distributed processing in receivers based on tensor for cooperative communications systems." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12792.
Повний текст джерелаEricsson Brasil
In this dissertation, we present a distributed data estimation and detection approach for the uplink of a network that uses CDMA at transmitters (users). The analyzed network can be represented by an undirected and connected graph, where the nodes use a distributed estimation algorithm based on consensus averaging to perform joint channel and symbol estimation using a receiver based on tensor signal processing. The centralized receiver, developed for a central base station, and the distributed receiver, developed for micro base stations, have their performances compared in a heterogeneous network. Then, two tensor-based receivers are proposed to be used in a relay-assisted network. In this case, the proposed receiver makes use of collaborative signal processing among relays to recover sources information before forwarding to the base station using a Decode-and-Forward protocol. The first receiver is based on the uncoded transmission of the tensor data reconstructed by the relays from the estimation of their factors matrix. The second one considers a tensor encoding of symbols estimated at the relays before transmission to the base station. The different proposed receivers are compared by means of computer simulations in terms of convergence and bit error rate.
Nesta dissertaÃÃo, apresentamos uma abordagem distribuÃda para a estimaÃÃo e detecÃÃo de dados para uplink em uma rede que emprega CDMA nos transmissores (usuÃrios). A rede analisada pode ser representada por um grafo sem direÃÃo e conectado, em que os nÃs fazem uso de um algoritmo de estimaÃÃo distribuÃda baseado em consenso mÃdio para realizar a estimaÃÃo conjunta de sÃmbolos transmitidos e do canal, utilizando um receptor baseado em processamento tensorial. O receptor centralizado, operando em uma EstaÃÃo RÃdio Base central, e o receptor distribuÃdo, operando em Micro EstaÃÃes RÃdio Base, tÃm seus desempenhos comparados em uma rede heterogÃnea. Em seguida, considerando-se uma rede assistida por repetidores, dois receptores tensoriais sÃo propostos. Neste caso, fazemos uso de um processamento de sinais colaborativo entre os repetidores para a recuperaÃÃo da informaÃÃo transmitida pela fonte, antes de ser encaminhada para estaÃÃo rÃdio base fazendo uso do protocolo Decode-and-Forward. O primeiro receptor à baseado na transmissÃo nÃo codificada do tensor de dados reconstruÃdo pelos repetidores a partir da estimaÃÃo de suas matrizes fatores. O segundo considera uma codificaÃÃo tensorial dos sÃmbolos previamente estimados nos repetidores antes da transmissÃo para estaÃÃo rÃdio base. Os diferentes receptores propostos sÃo comparados atravÃs de simulaÃÃes computacionais em termos de convergÃncia e taxa de erro de bit.
Timilsina, Santosh. "Physical Layer Security in Training-Based Single-Hop/Dual-Hop Massive MIMO Systems." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2376.
Повний текст джерелаPeron, Guilherme de Santi. "Esquemas de comunicação cooperativa com múltiplos relays e múltiplas antenas visando a eficiência energética." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2600.
Повний текст джерелаWireless sensor networks are usually composed of devices that require transmission quality, but with limited energy. From this condition arises the necessity of the energy efficiency study. In this document, we present and compare some techniques to improve the energy efficiency, which include the use of diversity, such as the use of multiple antennas in the transmitter and receiver as well as the use of cooperative communication. The latter has better results when a feedback channel is available. We cover two communication scenarios. In the first scenario, only the physical layer is taken into account in a MIMO cooperative network with multiple relays, where we propose a power allocation distributed iterative algorithm based on the Dinkelbach’s algorithm aiming at the energy efficiency maximization. The results show that the use of multiple antennas improve the energy efficiency, but depending on the used MIMO transmission scheme, the number of relays and the number of antennas can lead to different effects with respect to the energy efficiency. In the following, we present a scenario that contains a cross-layer analysis encompassing physical and medim access control (MAC) layers in a cooperative MIMO network, where we propose a distributed cooperative MAC protocol. In this case, besides the energy used to transmit thte data packets, we also analyze the delay and energy consumption to access the channel. Results show that the MIMO techniques improve the energy efficiency when we compare to SISO, especially when employing antenna selection techniques. In addition, other parameters, such as node density, spectral efficiency, number of antennas and distance between nodes, are analyzed with respect to the energy efficiency.
Abaza, Mohamed. "Cooperative MIMO techniques for outdoor optical wireless communication systems." Thesis, Brest, 2015. http://www.theses.fr/2015BRES0073/document.
Повний текст джерелаFree-space optical (FSO) communication has been the subject of ongoing research activities and commercial attention in the past few years. Such attention is driven by the promise of high data rate, license-free operation, and cheap and ecological friendly means of communications alternative to congested radio frequency communications. In most previous work considering multiple transmitters, uncorrelated channel conditions have been considered. An uncorrelated channel requires sufficient spacing between transmitters. However, this can be difficult and may not be always feasible in some applications. Thereby, this thesis studies repetition codes (RCs) and orthogonal space-time block codes performance in correlated log-normal FSO channels using intensity modulation and direct detection (IM/DD). Furthermore, the effect of different weather conditions on the average bit error rate (ABER) performance of the FSO links is studied. Multiple-input multiple-output (MIMO) FSO communication systems using space shift keying (SSK) modulation have been also analyzed. Obtained results show that SSK is a potential technique for spectral efficiencies equal or greater than 4 bits/s/Hz as compared to RCs with multiple pulse amplitude modulations. The performance analysis of a multi-hop decode and forward relays for FSO communication system using IM/DD is also considered in this thesis. It is shown that multi-hop is an efficient technique to mitigate atmospheric turbulence and different weather attenuation effects and geometric losses in FSO communication systems. Our simulation results show that multiple-input single-output (MISO) multi-hop FSO systems are superior to direct link and MISO systems over links exhibiting high attenuation. Meeting the growing demand for higher data rates communication networks, a system with full-duplex (FD) relays is considered. For such a system, the outage probability and the ABER performance are analyzed under different turbulence conditions, misalignment error and path loss effects. FD relays are compared with the direct link and half-duplex relays. Obtained results show that FD relays have the lowest ABER and the outage probability as compared to the two other systems. Finally, the obtained results in this thesis are very promising towards the next generation of FSO systems
Peron, Guilherme de Santi. "Método distribuído multiobjetivo de seleção de relays em redes cooperativas sem fio utilizando lógica fuzzy." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/326.
Повний текст джерелаIn this master thesis we present a new relay selection algorithm using fuzzy logic. The proposed algorithm is distributed, runs independently at each node, not requiring a central entity for coordination, and is multi-objective, since it aims to maximize both network lifetime and end-to-end throughput. The new method takes into account the instantaneous channel state of the relay-destination link and the residual energy of the node battery. As a result, the algorithm assigns a degree of relevance to each relay, such that the with a higher relevance is chosen to forward the source message. Results show that a considerable increase in the network lifetime can be obtained without compromising the end-to-end throughput.
Li, Kwan-leung, and 李君樑. "The European currency crisis: a replay of strains on bretton woods system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31954522.
Повний текст джерелаTödtling, Franz, Patrick Lehner, and Alexander Kaufmann. "Do different types of innovation rely on specific kinds of knowledge interactions?" Institut für Regional- und Umweltwirtschaft, WU Vienna University of Economics and Business, 2008. http://epub.wu.ac.at/306/1/document.pdf.
Повний текст джерелаSeries: SRE - Discussion Papers
Syed, Tamseel Mahmood. "Precoder Design Based on Mutual Information for Non-orthogonal Amplify and Forward Wireless Relay Networks." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1392043776.
Повний текст джерелаSouza, Alvaro Ricieri Castro e. "Eficiência energética e espectral em sistemas de comunicação sem fio: diversidade cooperativa, espacial e em frequência." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-27082018-091746/.
Повний текст джерелаModern wireless communication systems, such as the fourth generation (4G) ones, have as main objectives to provide high capacity and quality of service (QoS) for the users. In order to provide such capacity and QoS gain, 4G systems use several advanced transmission techniques and higher bandwidth, combined with resource allocation algorithms that are able to efficiently exploit such techniques, as for example taking advantage of the diversity dimensions of the system. Generally, however, it is also necessary to increase the transmission power to achieve the desired capacity gain, which implies increased costs for service providers, shorter lifetime for the mobile devices and increasingly pronounced environmental impact. Since the expectation is that the number of users and data necessity will continue growing rapidly, it is evident the importance of analyzing the relation between capacity and power expended by the system. This relation can be seen through the energy efficiency (EE) metric, which is given by the ratio between the number of effectively received information bits and the energy consumed in the transmission process, revealing how efficiently the system transform consumed energy into effectively recovered information at the receiver. A system optimized regarding EE is able to transmit more information per unit of energy consumed, resulting in a more rational and efficient utilization of the scarce energetic resources. A second issue is relative to the distribution of the capacity/QoS gains over the whole cell, i.e, which users will be able to take advantage of the higher capacity and QoS. In urban macrocellular environments, the path-loss can reach several tens of decibels in relatively short distances, in addition to natural obstacles, such as land relief, or artificial, such as buildings, which further limits the development of energetically efficient systems. In traditional approaches, such problems require the use of high transmission power, generally greater than the power that the devices can use, or else require increased density of base-stations (BSs), which generally results in unviable costs from the operators point of view. Thus, in 4G systems it is sought to emulate the increase in the density of BSs through the concept of heterogeneous networks, which are cells with smaller coverage area installed in critical points of the original macrocell coverage, as for example the cell-edge area, serving efficiently the users. In the heterogeneous networks scenario, one of the main paradigms is the concept of cooperative networks, in which relay stations (RSs) retransmit the signal received from the source station to the destination station, reducing the power consumed with the mobile wireless channel. As the RSs use a wireless connection to the BS, they can be installed in places with poor infrastructure without requiring major modifications, resulting in very flexible deployments. Thus, this PhD work aims to investigate resource allocation strategies based on the improvement of the energy efficiency for fourth and fifty generation cellular systems using the cooperative networks paradigm, determining potentialities and also items that need to be modified, optimized or even redefined, aiming to a substantial increase in the overall energy efficiency of the wireless communication network. It is sought during the development of the system model to capture and quantify the main features of important cellular systems currently in use, i.e., LTE-A and WiMAX, so that the design decisions consider the standardization efforts, but do not be limited by them. Since the EE-based resource allocation approach can impact the performance metrics of the system, it will be investigated also the tradeoff between energy and spectral (SE) efficiencies, so that the increase in energy efficiency is not caused by degradation of the SE and also to be possible to obtain a higher EE for a same SE and QoS.
Jayasinghe, L. K. (Laddu Keeth Saliya). "Analysis on MIMO relaying scenarios in wireless communication systems." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207391.
Повний текст джерелаTiivistelmä Tässä väitöskirjassa keskitytään arvioimaan ja parantamaan suorituskykyä useissa moniantennitoistinjärjestelmissä, jotka ovat ajankohtaisia tulevaisuuden langattomissa verkoissa. Erityisesti työssä analysoidaan tärkeitä käytännön tilanteita, sisältäen toistimien sijoittamisen, kanavatiedon saatavuuden, rajoitetun taajuuskaistan ja tiedon salauksen. Aluksi epäkoherentin, vahvistavan ja jatkolähettävän moniantennitoistimen suorituskykyä analysoidaan tilanteessa, jossa toistin on sijoitettu siten, että kohteeseen on suora yhteys. Suorituskyvyn arvioinnin pääkohteena on ortogonaalinen tila-aika-tason lohkokoodattu epäkoherentti vahvistava ja jatkolähettävä moniantennitoistin. Työssä johdetaan tarkat lausekkeet tilastollisille parametreille ja suorituskykymittareille ottaen huomioon hetkellinen signaalikohinasuhde vastaanottimessa. Nämä suorituskykymittarit ilmaisevat, että toistimen ja kohteen välillä oleva vahva suoran yhteyden komponentti rajoittaa sitä suorituskykyä, jota moniantennijärjestelmän hajontaympäristö ennustaa. Työssä tutkitaan myös kahdensuuntaisia moniantennitoistimia, jotka käyttävät fyysisen kerroksen verkkokoodausta. Koodauksesta tulee monimutkaista, kun monia datavirtoja yhdistetään toistimessa. Tämän helpottamiseksi käytetään yhdistettyä esikoodaus-dekoodausmenetelmää, jota tutkitaan erilaisten kanavatietojen tapauksissa. Täydellisen kanavatiedon tapauksessa käytetään nollaanpakotuskriteeriä. Epätäydellisen kanavatiedon tapauksessa käytetään robustia yhdistettyä esikoodaus-dekoodausmenetelmää. Esikoodaus- ja dekoodausmatriisit saadaan ratkaisemalla optimointiongelmat. Nämä ongelmat on muodostettu maksimoimaan summadatanopeus, ja minimoimaan painotettu keskineliövirhe, kun optimointirajoitteina ovat solmujen lähetystehot. Seuraavaksi esikoodaus-dekoodausmenetelmää tutkitaan moniantennijärjestelmässä, jossa käytetään kahdentyyppistä laitteesta-laitteeseen (D2D) kommunikaatiomenetelmää: fyysisen kerroksen verkkokoodaukseen pohjautuvaa D2D- ja suoraa D2D-kommunikaatiota. Yhteissuunnittelu perustuu keskineliövirheen minimointiin, joka on hyödyllistä, kun halutaan vähentää häiriötä ja parantaa molempien verkkojen suorituskykyä. Työssä ehdotetaan hajautettuja ja keskitettyjä algoritmeja tilanteessa, jossa käytetään kaksisuuntaista kommunikaatiota molemmissa verkoissa. Järjestelmän suorituskykyä arvioidaan, kun käytetään kahta eri lähetystilan valintaa, dynaamista ja staattista. Tulokset osoittavat, että fyysisen kerroksen verkkokoodaukseen pohjautuva D2D kasvattaa D2D-kommunikaatiojärjestelmän kantamaa. Lopuksi, turvallisia keilanmuodostustekniikoita arvioidaan fyysisen kerroksen verkkokoodaukseen pohjautuvassa kahdensuuntaisessa moniantennitoistinjärjestelmässä, kun useat salakuuntelijat yritävät siepata käyttäjätiedon. Käyttäjillä on epäideaalinen kanavatieto heidän ja salakuuntelijoiden välisten linkkien kanavista. Kanavatiedon estimointivirheitä arvioidaan ellipsoidisella ja Gauss-Markov-epävarmuusmallilla. Robustit optimointiongelmat, joissa suunnitellaan keilanmuodostusvektorit käyttäjän ja toistimen välille, muodostetaan molemmille malleille. Numeeriset tulokset osoittavat, että ehdotetut algoritmit konvergoituvat nopeasti ja tarjoavat korkeamman turvallisuuden
Cardone, Martina. "Techniques de coopération appliquées aux futurs réseaux cellulaires." Thesis, Paris, ENST, 2015. http://www.theses.fr/2015ENST0020/document.
Повний текст джерелаA uniform mobile user quality of service and a distributed use of the spectrum represent the key-ingredients for next generation cellular networks. Toward this end, physical layer cooperation among the network infrastructure and the wireless nodes has emerged as a potential technique. Cooperation leverages the broadcast nature of the wireless medium, that is, the same transmission can be heard by multiple nodes, thus opening up the possibility that nodes help one another to convey the messages to their intended destination. Cooperation also promises to offer novel and smart ways to manage interference, instead of just simply disregarding it and treating it as noise. Understanding how to properly design such cooperative wireless systems so that the available resources are fully utilized is of fundamental importance.The objective of this thesis is to conduct an information theoretic study on practically relevant wireless systems where the network infrastructure nodes cooperate among themselves in an attempt to enhance the network performance in many critical aspects, such as throughput, robustness and coverage. Wireless systems with half-duplex relay stations as well as scenarios where a base station overhears another base station and consequently helps serving this other base station's associated mobile users, represent the wireless cooperative networks under investigation in this thesis. The prior focus is to make progress towards characterizing the capacity of such wireless systems by means of derivation of novel outer bounds and design of new provably optimal transmission strategies
Liu, Lingfeng. "Cooperative wireless channel characterization and modeling: application to body area and cellular networks." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209722.
Повний текст джерелаIn the part of BANs, the dynamic narrowband on-body channels under body motions are modeled statistically on their temporal and spatial fading based on anechoic and indoor measurements. Common body scattering is observed to form inter-link correlation between links closely distributed and between links having synchronized movements of communication nodes. An analytical model is developed to explain the physical mechanisms of the dynamic body scattering. The on-body channel impacts to simple cooperation protocols are evaluated based on realistic measurements.
In the part of cellular networks, the cluster-level multi-link COST 2100 MIMO channel model is developed with concrete modeling concepts, complete parameterization and implementation methods, and a compatible structure for both single-link and multi-link scenarios. The cluster link-commonness is introduced to the model to describe the multi-link properties. The multi-link impacts by the model are also evaluated in a distributed MIMO system by comparing its sum-rate capacity at different ratios of cluster link-commonness.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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.
Повний текст джерелаThis thesis deals with the estimation of the multihop Amplify-and-Forward relay communications. The various objects (transmitter, relays, receivers) can be fixed or mobile. Each link is modeled by a flat fading Rayleigh channel, with a Doppler spectrum resulting from two-dimensional (2D, leading to the U-shape Dopller spectrum) or three-dimensional (3D, leading to a flat Doppler spectrum) scattering environments. The cascade of channel hops is approximated by a first-order autoregressive (AR(1)) model and is tracked by a standard estimation algorithm, the Kalman Filter (KF). The common method used in the literature to tune the parameter of the AR(1) model is based on a Correlation Matching (CM) criterion. However, for slow fading variations, another criterion based on the off-line Minimization of the Asymptotic Variance (MAV) of the KF is shown to be more appropriate. For both the CM and MAV criteria, this thesis gives analytic justification by providing approximated closed-form expressions of the estimation variance in output of the Kalman filter, and of the optimal AR(1) parameter. The analytical results are calculated for given Doppler frequencies and Signal-to-Noise Ratio for both scattering environments, whatever the number and type of transmission hops (Fixed-to-Mobile or Mobile-to-Mobile). The simulation results show a considerable gain in terms of the Mean Square Error (MSE) of the well tuned Kalman-based channel estimator, especially for the most common scenario of slow-fading channel
Ronchini, Ximenes Leandro. "Approches tensorielles pour les systèmes de communication MIMO avec relais." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4009/document.
Повний текст джерелаIn cooperative communication systems, two or more transmitting terminals arecombined to increase the diversity and/or the power of the signals arriving at aparticular receiver. Recently, the so-called tensor analysis has been an efficient approach for channel estimation in systems with cooperative diversity. However, among the few works devoted to this task, the utilization of the PARAFAC tensor decomposition for modeling the received signals did not allow the development of techniques for joint symbol and channel estimation. Aiming to avoid the use of pilot-based sequences, the objective of this thesis is to provide new tensor-based strategies, including transmission systems and semi-blind receivers, for one-way two-hop relaying systems. Based on a Khatri-Rao space-time coding at the source and two different Amplify-and-Forward (AF) relaying strategies, two transmission systems are proposed. For these systems, named PT2-AF and NP-AF, the received signals at the destination node follow respectively a PARATUCK2 and a nested PARAFAC tensor model. Exploiting uniqueness properties of these tensor models which are established in the thesis, several semi-blind receivers are derived. Some of these receivers are of iterative form using an ALS algorithm, whereas some other ones are close-form solutions associated with Khatri-Rao factorizations. Some simulation results are finally presented to illustrate the performance of the proposed receivers which are compared to some state-of-the-art supervised techniques
Liu, Chih-Sheng, and 劉稚聖. "Study in relay ordering in wireless cooperative communication system." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68511788036471983930.
Повний текст джерела國立中興大學
通訊工程研究所
102
In this paper,we first propose Algorithm of relay ordering for a wireless multihop cooperative diversity network. This Algorithm of relay ordering reduce the relay used than present research. Furthermore, for reduce the relay used more another step. We second propose another Algorithm of relay ordering in a different relay selection mechanism. Indeed the second Algorithm of relay ordering reduce more relay used than the first Algorithm. In the other hand we third propose two-stage stable matching algorithm of relay ordering which base on the stable matching framework in solving networking problem, which are traditionally solved using utility-based optimization or game theory. For a cooperative network with multiple relays, we simulate to performance of these Algorithm by using an approximate end-to-end signal-to-noise ratio expression. The analysis and the numerical results demonstrate that these selection mechanism of relay ordering shown below. Finally, the simulation results illustrate the performance of the proposed relay selection mechanism.
Lu, Yuan-Kang, and 呂元剛. "An Improved OFDM-Based Cooperative Relay System Using Conjugate Transmission." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/34030917853309827769.
Повний текст джерела國立清華大學
通訊工程研究所
101
In this thesis, we investigate intercarrier interference (ICI) cancellation for OFDM-based cooperative relay systems using conjugate transmission. First, we modify an existing adaptive receiver for such systems by introducing a new amplitude scaling factor for each subcarrier. The presented amplitude scaling factor is optimized by a carrier-to-interference-plus-noise ratio (CINR) criterion derived under multipath environments, rather than by the carrier-to-interference ratio (CIR) derived under AWGN channels in a previous scheme. With the proposed adaptive receiver, we then develop a relay selection method based on a max-min CINR criterion for OFDM-based cooperative relay systems using conjugate transmission, where the frequency offset and channel state information are jointly considered for relay selection. Computer simulation results demonstrate that the proposed adaptive receiver and the proposed relay selection method outperform previous related schemes in terms of the bit-error-rate performance.
Chiu, Han-Chiuan, and 邱翰銓. "Precoding Design in Two-Way Cooperative System with Energy Harvesting Relay." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/64785606245180005933.
Повний текст джерела國立中山大學
電機工程學系研究所
102
Due to rapid development of mobile communications, radio-frequency signals are surrounded in our environment. Besides conveying information, the ambient radio-frequency signal has gradually been utilized for energy harvesting. Radio Frequency energy harvesting begins from the fact that people gradually rely on mobile applications, such as communication apps., picturing software, and games, in their daily life. However, these applications are energy consuming. Although these devices can be charged through portable power bank, the energy stored in the power bank is still limited, which leads to inconvenience when the power bank is in outage. To provide further convenience, RF energy harvesting has been developed to avoid mobile devices suffering power outage by gathering energy from from the ambient radio frequency signals and transferring into electricity. Furthermore, simultaneously processing information and harvesting energy from the RF signal has been studied extensively in recent years. In this thesis, we will employ this technique in two-way amplify-and-forward relay system, where two users exchange information under assistance of an energy-harvesting relay node. Specifically speaking, transmission power of the relay node depends on the electrical energy harvested in previous phase. We assume that the relay node is equipped with two antennas, while the users are equipped with a single antenna. With perfect channel information, the relay node can coherently combines the signals received at two antennas, so that the relay node is able to gather more energy. In this thesis, we proposed a joint design of a precoding matrix and power-slitting ratios for the relay node to maximize the sum-rate of two users under a constraint that the transmission power of the relay node cannot exceed the harvested energy. However, this optimization problem is neither convex nor concave, and it can’t be solved by CVX tool. Thus, we divide the problem into two sub-problems to approach a locally-optimal solution of the precoding matrix and power-splitting ratios in an iterative manner. Specifically, we employ gradient algorithm to obtain power-splitting ratios with initial value obtained by exhaustively searching over a rough grid. Then, the beamforming matrix is obtained using power iteration algorithm. After several iterations, two subproblems get converged and we can find the set of suboptimal solutions. It shows through simulation results that the proposed scheme can effectively improve the spectrum efficiency of the system.
Chopra, Khyati. "Secrecy performance analysis of threshold-based cognitive and cooperative relay system with diversity reception." Thesis, 2018. http://eprint.iitd.ac.in:80//handle/2074/7936.
Повний текст джерелаYeh, Tzu-Ming, and 葉子鳴. "Relay Selection in the Cooperative Communication System Based on the Maximum Security Capacity." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/448vnn.
Повний текст джерела臺北市立大學
資訊科學系碩士在職專班
107
In the wireless communication development of nowadays, the need for information communicating medias is also elevated by prosperity of multi-media internet. The created wireless bandwidth demand is rapidly growing with various applications, and cooperative communication could support to improve wireless communication system efficiency through Spatial Diversity. In the wireless communication system based on the cooperative communication, all nodes can take different roles simultaneously as node for sending, node for relay, and receive destination. Through mutual association and forwarding among nodes, this could lead to a more reliable and efficient information transmission. With these facts, the hardware complexity and cost could be lowered and reduce demand for basic establishment to build a low-cost internet. Therefore, how to use cooperative communication system to transmit with maximum security capacity has become an important issue. In most wireless transmission, each node proceeds broadcast in the air in open environment, and hence most security threats would come from signal interception and information eavesdropping by disguised relay. Traditionally, the process of packet encryption and decryption with key needs to cost massive calculation resource which is the process in high level of network. However, physical layer actually has the safely transmission ability. To achieve relay selection with maximum secrecy capacity, this article applies AF mode and CF mode to compliment with MRC and SC as receive station mode to achieve maximum bandwidth capacity. On the maximum security capacity calculation, we apply method of exhaustion to achieve best result and to prove effectiveness of the algorithm.
Bansal, Gaurav. "Cooperative Communication In Store And Forward Wireless Networks Using Rateless Codes." Thesis, 2010. https://etd.iisc.ac.in/handle/2005/2225.
Повний текст джерелаBansal, Gaurav. "Cooperative Communication In Store And Forward Wireless Networks Using Rateless Codes." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/2225.
Повний текст джерелаMEHRPOUYAN, 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.
Повний текст джерелаThesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2010-07-29 16:52:50.272
Chen, Moyuan. "Single and multiple user pair cooperation schemes with delay issues." Thesis, 2011. http://hdl.handle.net/1828/3530.
Повний текст джерелаGraduate
Lai, Chih-Ming, and 賴志銘. "The Relay Selection of Dynamic Decode and Forward Protocol With Cooperative Network Coding System." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/16967657124059417896.
Повний текст джерела國立中正大學
通訊工程研究所
101
Cooperative communication is a very popular research area, and it plays an important role in the new generations of wireless communications. Network coding technology combines several messages, and transmit the mixed messages into next receiver for providing higher transmitting throughput and performance. This thesis builds a wireless communication system combined with dynamic decode and forward (DDF) and network coding technology. We consider the situation when the system has multiple relays, how to select a proper relay? We research outage probability of this system under Rayleigh, Rician and Nakagami fading channels. We choose a single relay to transmit, and derive the theoretical value of outage probability. Last, we compare theoretical value with simulation result. After simulation and analysis, we find whether the system can transmit successfully in the network coding stage is the main factor in affecting outage probability, and we know when we get more relays, outage probability is lower.
Bharadwaj, Sachin. "Analysis and Optimization of Cooperative Amplify-and-Forward Relaying with Imperfect Channel Estimates." Thesis, 2013. http://etd.iisc.ac.in/handle/2005/3279.
Повний текст джерелаBharadwaj, Sachin. "Analysis and Optimization of Cooperative Amplify-and-Forward Relaying with Imperfect Channel Estimates." Thesis, 2013. http://hdl.handle.net/2005/3279.
Повний текст джерела