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Nair, Sidharth. "A Multiple Antenna Global Positioning System Configuration for Enhanced Performance." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1090937438.
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Ghosh, Soham. "Compact multiple-antenna structures." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110651.
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Multiple-Input-Multiple-Output (MIMO) communications, which employ multiple antennas at the transmitter and receiver, have become quite ubiquitous today due to its capability to increase the system spectral efficiency and reliability. With the current niche of miniaturization of communication devices, one of the key problems is the design of low-profile multi-antennas. Moreover, when the antenna elements are too close to each other, the inherent problem of mutual coupling can greatly reduce the system capacity. Addressing these two issues at the same time remains an engineering challenge given the spatial constraints inside the device. This thesis investigates antenna miniaturization, mutual coupling reduction and antenna performance characterization for various realistic channel scenarios. Electromagnetic Band-Gap structures are used to reduce the size and mutual coupling of multi-element Microstrip Patch Antennas (MPAs), which can be envisioned to be incorporated in WLAN/LTE base-stations. Furthermore, ultra-miniaturized multi-element Planar Inverted-F Antennas (PIFAs) exploiting pattern and polarization diversity are proposed for receiver terminals, such as a handheld device. The capacity and diversity performance of these multi-antennas have been evaluated in free-space and various fading environments.Les systèmes de communication à entrée multiple sortie multiple, utilisant plusieurs antennes à l'émetteur et au récepteur, sont devenus omniprésents de nos jours en raison de leur capacité d'augmenter le rendement spectral et la fiabilité du système. Avec le marché de niche actuelle dans la miniaturisation des périphériques de communication, l'un des principaux problèmes est la conception d'antennes multiples avec un profile modéré. De plus, quand les antennes sont trop proche les uns des autres, le problème inné de couplage mutuel peut réduire substantiellement la capacité du système. Trouver une solution qui résout deux problèmes simultanément demeure un défi d'ingénierie compte tenu des contraintes d'espace à l'intérieur des périphériques. Ce mémoire examine la miniaturisation des antennes, la réduction du couplage mutuel, et la caractérisation de la performance des antennes dans divers scénarios avec des voies de transmissions réalistes. Les structures de bande interdite électromagnétique sont utilisées pour réduire les dimensions et le couplage mutuel dans les antennes planaires à microrubans (MPA) multiples. Ces structures peuvent être envisagées pour être incorporées dans les stations de base de technologie d'évolution à long terme (LTE) et de réseau local sans fil (WLAN). De plus, des antennes planaires F inversées (PIFA) ultra-miniatures à éléments multiples qui exploitent les diversités du motif et de la polarisation sont proposées pour les terminaux récepteurs tels que les périphériques de poche. La capacité et la performance de la diversité de ces antennes multiples sont évaluées dans l'espace libre et dans divers environnements d'évanouissement.
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Evans, Daniel N. "Near-Optimal Antenna Design for Multiple Antenna Systems." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd2796.pdf.
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Zarei, Hossein. "RF variable phase shifters for multiple smart antenna transceivers /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5964.
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Sandhu, Waseem Hussain, and Muhammad Awais. "MULTIPLE ANTENNA TECHNIQUES IN WiMAX." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1120.
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Now-a-days wireless networks such as cellular communication have deeply affected human lives and became an essential part of it. The demand to buy high capacity and better performance devices and cellular services has been rapidly increased. There are more than two hundred different countries and almost three billion users all over the world which are using cellular services provided by Global System for Mobile (GSM), Universal Mobile Telecommunication System (UMTS), Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX). In the past decade, one antenna is connected to only one communication radio device at the same time but currently this scenario has been completely changed. To increase the capacity of the channels and to improve the bit error performance between mobile station and service station, it is now possible to connect one antenna with more than one communication radio device at the same time. Multiple Input Multiple Output (MIMO) systems are designed to obtain this requirement. In MIMO systems, antennas are combined in the form of small frames like coupling in cellular devices. Diversity means to obtain successful transmission and reception of radio signals with accordance to polarization and correlation. Due to diversity the capacity of the channels and bit error rate are improved, so diversity is one of the main and important properties of MIMO systems. This thesis is emphasized to study WiMAX systems by implementing multiple antenna techniques, by observing the bit error rate performance and data rate in WiMAX systems using two important and currently widely applied multiple access communication techniques. The research will also elaborate these techniques and explain the basic parameters, operations, mathematical calculations and different relevant observations. The simulation tool used in this research thesis is MATLAB which is also used to illustrate the results with figures and graphs.Nu för tiden trådlösa nätverk såsom cellulär kommunikation har stor påverkan på människors liv och blev en viktig del av det. Kravet att köpa hög kapacitet och bättre utrustning prestanda och mobiltelefoni har snabbt ökat. Det finns mer än två hundra olika länder och nästan tre miljarder användare över hela världen som använder mobiltelefoni som Global System for Mobile (GSM), Universal Mobile Telecommunication System (UMTS), Wireless Local Area Network (WLAN) och Worldwide Interoperability för Microwave Access (WiMAX). Under det senaste decenniet har en antenn ansluten till en kommunikationsradio enhet vid samma tidpunkt, men för närvarande detta scenario har fullständigt förändrats. Att öka kapaciteten av kanalerna och för att förbättra prestandan lite fel mellan mobil station och bensinstationen, är det nu möjligt att ansluta en antenn med mer än en kommunikationsradio enhet samtidigt. Multiple Input Multiple Output (MIMO) system är utformade för att uppnå detta krav. I MIMO-system, antenner kombineras i form av små ramar som kopplingsanordningar i cellulär enheter. Mångfald innebär att få lyckad överföring och mottagning av radiosignaler i enlighet med polarisation och korrelation. På grund av mångfalden kapacitet av kanalerna och bit error rate förbättras, så att mångfald är en av de största och viktigaste egenskaper MIMO-system. Denna avhandling är betonas att studera WiMAX system genom att genomföra flera antenn teknik, genom att observera bitars prestanda felfrekvensen och datahastighet i WiMAX system med hjälp av två viktiga och som för närvarande tillämpas allmänt flera tekniker tillgång kommunikation. Forskningen kommer också att utveckla dessa metoder och förklara de grundläggande parametrarna, operationer, matematiska beräkningar och olika relevanta iakttagelser. Den simuleringsverktyg som används i denna forskning avhandling är MATLAB som också används för att illustrera resultaten med siffror och diagram.
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Ray, Siddharth 1979. "Energy efficient multiple antenna communication." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38228.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (leaves 111-115).
We consider a multiple-input, multiple-output (MIMO) wideband Rayleigh block fading channel where the channel state is unknown at the transmitter and receiver and there is only an average input power constraint. We compute the capacity and analyze its dependence on coherence length, number of antennas and receive signal-to-noise ratio (SNR) per degree of freedom. We establish conditions on the coherence length and number of antennas for the non-coherent channel to have a "near coherent" performance in the wideband regime. We also propose a signaling scheme that is near-capacity achieving in this regime. We compute the decoding error probability and study its dependence on SNR, number of antennas and coherence length. We show that error probability decays inversely with coherence length and exponentially with the product of the number of transmit and receive antennas. Moreover, in the wideband regime, channel outage dominates error probability and the critical and cut-off rates are much smaller than channel capacity. In the second part of this thesis, we introduce the concept of a fiber aided wireless network architecture (FAWNA), which allows high-speed mobile connectivity by leveraging the speed of optical networks.
(cont.) Specifically, we consider a single-input, multiple-output (SIMO) FAWNA, which consists of a SIMO wireless channel interfaced with an optical fiber channel through wireless-optical interfaces. We propose a design where the received wireless signal at each interface is sampled and quantized before being sent over the fiber. The capacity of our scheme approaches the capacity of the architecture, exponentially with fiber capacity. We also show that for a given fiber capacity, there is an optimal operating wireless bandwidth and number of interfaces. We show that the optimal way to divide the fiber capacity among the interfaces is to ensure that each interface gets enough rate so that its noise is dominated by front end noise rather than by quantizer distortion. We also show that rather than dynamically change rate allocation based on channel state, a less complex, fixed rate allocation scheme can be adopted with very small loss in performance.
by Siddharth Ray.
Ph.D.
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Gopala, Kalyana. "Multiple Antenna Communications for 5G." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS352.
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Duplexage par division dans le temps (TDD) Massive Multiple Input Multiple Output (MaMIMO) dépend de la réciprocité de canal pour obtenir des informations d'état de canal au niveau de l'émetteur (CSIT). Toutefois, le canal numérique global de bout en bout n’est pas réciproque en raison de la présence de chaînes de transmission (Tx) et de réception (Rx), qui doivent être corrigées à l’aide de facteurs de calibration. Nous fournissons une expression simple et élégante du Cramér-Rao Bound (CRB) pour l’estimation des paramètres de calibration. Nous analysons des approches des moindres carrés existants et proposons des algorithmes optimaux. Nous considérons également la beamforming pour une liaison MIMO point à point variant rapidement dans le temps. Dans un système Orthogonal Frequency Division Multiplexing (OFDM), il en résulte une interférence entre porteuses (ICI). Avec une hypothèse de variation linéaire de canal à travers le symbole OFDM, il a été observé que le problème est similaire à celui d'une conception de beamformer MIMO par canal de diffusion à interférence (IBC). Le design du beamformer prend en compte le fenêtrage de réception en utilisant le préfixe cyclique en excès. En plus de la CSIT complète, nous étudions également des approches qui maximisent le Expected Weighted Sum Rate (EWSR) lorsque la Tx n’a qu’une connaissance partielle du canal. Premièrement, nous utilisons une approximation de système large qui fonctionne également bien pour un petit nombre d’antennes Tx et Rx. Nous analysons également la possibilité d’utiliser la métrique Expected-signal-expected-interference-WSR de signal EWSR. Enfin, les résultats expérimentaux sont présentésTime Division Duplexing (TDD) Massive Multiple Input Multiple Output (MaMIMO) with a massive number of base station (BS) antennas relies on channel reciprocity to obtain Channel State Information at Transmitter (CSIT). However the overall end to end digital channel is not reciprocal due to the presence of Transmit (Tx) and Receive (Rx) chains which need to be corrected using calibration factors. Our work provides a simple and elegant expression of the Cramer Rao Bound (CRB) for calibration parameter estimation. We provide analysis for the existing least squares approaches and propose optimal algorithms to estimate the calibration parameters. We also consider beamforming for a rapidly time-varying point to point MIMO link. In an Orthogonal Frequency Division Multiplexing (OFDM) sytem, this results in inter-carrier interference (ICI). With an assumption of linear channel variation across the OFDM symbol, it is observed that the beamformer design problem is similar to that of a MIMO Interfering Broadcast Channel (IBC) beamforming design. The beamformer design takes into account receive windowing using the excess cyclic prefix and the window is jointly designed with the Tx beamformer. In addition to full CSIT, we also investigate partial CSIT approaches that maximize Expected Weighted Sum Rate (EWSR) where the Tx has only partial knowledge of the channel. First, we use a large system approximation that also works well for a small number of Tx and Rx antennas to derive the beamformers. In our work, we also analyze the possibility of using the Expected-signal- expected-interference-WSR metric instead of the EWSR. Finally, experimental results on the Eurecom MaMIMO testbed are presented
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Stewart, Scot Howard. "Multiple feed reflector antenna analysis." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/94472.
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A method of calculating the secondary pattern of a reflector illuminated by a feed array is developed. Geometrical optics is used to determine the incident field via a coordinate transformation approach. The incident field from each element is superimposed to form the total field used in finding the surface currents of the physical optics radiation integral. The technique allows each element to be arbitrarily excited, positioned and oriented. The element patterns may be different allowing mutual coupling to be included.M.S.
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Li, Hui. "Decoupling and Evaluation of Multiple Antenna Systems in Compact MIMO Terminals." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96239.
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Research on multiple antenna systems has been a hot topic in recent years due to the demands for higher transmission rate and more reliable link in rich scattering environment in wireless communications. Using multiple antennas at both the transmitter side and the receiver side increases the channel capacity without additional frequency spectrum and transmitted power. However, due to the limited space at the size-limited terminal devices, the most critical problem in designing multiple antennas is the severe mutual coupling among them. The aim of this thesis is to provide compact, decoupled and efficient multiple antenna designs for terminal devices. At the same time, we propose a simple and cost effective method in multiple antenna measurement. All these efforts contribute to the development of terminal devices for the fourth generation wireless communication. The background and theory of multiple antenna systems are introduced first, in which three operating schemes of multiple antenna systems are discussed. Critical factors influencing the performance of multiple antenna systems are also analyzed in details. To design efficient multiple antenna systems in compact terminals, several decoupling methods, including defected ground plane, current localization, orthogonal polarization and decoupling networks, are proposed. The working mechanism and design procedure of each method are introduced, and their effectiveness is compared. Those methods can be applied to most of the terminal antennas, reducing the mutual coupling by at least 6dB. In some special cases, especially for low frequency bands below 1GHz, the chassis of the device itself radiates like an antenna, which complicates the antenna decoupling. Thus, we extend the general decoupling methods to the cases when the chassis is excited. Based on the characteristic mode analysis, three different solutions are provided, i.e., optimizing antenna locations, localizing antenna currents and creating orthogonal modes. These methods are applied to mobile phones, providing a more reliable link and a higher transmission rate, which are evaluated by diversity gain and channel capacity, respectively. In order to measure the performance of multiple antenna systems, it is necessary to obtain the correlation coefficients. However, the traditional measurement technique, which requires the phase and polarization information of the radiation patterns, is very expensive and time consuming. In this thesis, a more practical and convenient method is proposed. Fairly good accuracy is achieved when it is applied to various kinds of antennas. To design a compact and efficient multiple antenna system, besides the reduction of mutual coupling, the performance of each single antenna is also important. The techniques for antenna reconfiguration are demonstrated. Frequency and pattern reconfigurable antennas are constructed, providing more flexibility to multiple antenna systems.QC 20120604
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Mukherjee, Souvick. "Multiple antenna microwave ablation: impact of non-parallel antenna insertion." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19058.
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Master of ScienceDepartment of Electrical and Computer Engineering
Punit Prakash
Microwave ablation is a minimally invasive therapeutic modality used for the treatment of cancer in various organs. In this procedure, microwave energy is sent through a thin antenna placed inside the tumor. The microwave energy radiated from the antenna generates heat which kills the tumor cells by necrosis. During multiple-applicator microwave ablation, geometric estimates of treatment outcome are typically obtained by assuming parallel insertion of the applicators. This assumption is based on the guidelines provided in the brochures of antenna manufacturing companies. This assumption is flawed because it is rare to insert the antennas in parallel configuration due to the flexible nature of the antennas and the presence of intervening organs. Furthermore, movement of patients during the treatment procedure alters the position of the antennas. In order to see the effect of non-parallel insertion of antennas, model-based treatment planning may be instructive. Treatment planning can also determine the changes needed to be made for prospective ablation therapy if the antennas are not positioned in their ideal parallel configuration. This thesis provides a detailed computational comparison of the skewed configurations of microwave antennas to their closest parallel configurations. The metric used for com-paring the similarity between the cases is Dice Similarity Coefficient (DSC). Experimental results to validate the computational data are also discussed. Computations were done by using realistic cases of antenna positions obtained from Rhode Island Hospital.
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Lu, Di. "Antenna selection schemes for multiple-input multiple out systems." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493529.
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Theoretical research show that wireless communication systems using multiple-input multiple-output (MIMO) antennas can provide a very high spectral efficiency in rich scattering environments. This thesis investigates issues of antenna selection in MIMO systems with an emphasis on the criteria and algorithms of receive antenna selection in layered spatial multiplexing architectures.
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Trujillo, Castañeda Eduardo Daniel. "Resource allocation for multiple-user multiple-antenna cellular systems." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14078.
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Doutoramento em Engenharia ElectrotécnicaThe thesis addresses the sum rate or spectral e ciency maximization problem in cellular systems with two main components, multiple antennas and multiple users. In order to solve such a problem, several resource allocation techniques are studied and developed for di erent cellular scenarios. The antennas at the transmitters are arranged in several con gurations, i.e., co-located or distributed and for such arrangements di erent levels of coordination and cooperation between transmitters are investigated. Accounting for more receiver antennas than transmitter antennas implies that system optimization must select the best transmitter-receiver match (combinatorial problem) which can be solved with di erent degrees of cooperation between transmitters. The system models studied can be classi ed either as interference limited or as power limited systems. In interference limited systems the resource allocation is carried out independently by each transmitter which yield power leakage to unintended receivers. For this kind of systems, the access network using distributed antenna architectures is examined. The properties of distributed antenna in cellular systems as well as the gains they provide in terms of frequency reuse and throughput are assessed. Accounting for multiple user scenarios, several techniques and algorithms for transmitter-receiver assignment, power allocation, and rate allocation are developed in order to maximize the spectral e ciency. In power limited systems the transmitters jointly allocate resources among transmit and receive antennas. The transmitters are equipped with multiple antennas and signal processing is implemented in order to suppress inter-user interference. Single-cell and multi-cell systems are studied and the problem of sum rate maximization is tackled by decoupling the user selection and the resource allocation (power and precoding) processes. The user selection is a function of the type of precoding technique that is implemented and the level of information that can be processed at the transmitter. The developed user selection algorithms exploit information provided by novel channel metrics which establish the spatial compatibility between users. Each metric provides a di erent trade-o between the accuracy to identify compatible users, and the complexity required to compute it. Numerical simulations are used to assess the performance of the proposed user selection techniques (metrics and algorithms) whose performance are compared to state-of-the-art techniques.
Esta tese descreve o problema da maximização da taxa de transmissão ou e ciência espectral em sistemas moveis tomando em atenção duas características fundamentais destes, o número de antenas e utilizadores. A fim de resolver este tipo de problema, várias técnicas de alocação de recursos foram estudadas e propostas para diferentes cenários. As antenas nos transmissores estão organizadas em diferentes configurações, podendo ser localizadas ou distribuídas e para estes esquemas, diferentes níveis de cooperação e coordenação entre transmissores foram investigados. Assumindo mais antenas receptoras do que antenas transmissoras, implica que a otimização do sistema seleccione as melhores combinações de transmissor-receptor (problema combinatório), o que pode ser concretizado usando diferentes graus de cooperação entre transmissores. Os modelos de sistemas estudados, podem ser classificados como sistemas limitados por interferência ou sistemas limitados por potência. Em sistemas limitados por interferência a alocação de recursos e feita independentemente para cada transmissor o que resulta em perda de energia para os receptores não tomados em consideração. Para este tipo de sistemas, e considerado o caso em que a rede de acesso e constituída por antenas distribuídas. Os ganhos obtidos devido ao uso de antenas distribuídas, quer em termos do planeamento de frequências quer da maximização da taxa de transmissão são considerados. Assumindo esquemas multi-utilizador, várias técnicas e algoritmos de transmissão-recepção, alocação de potência e de taxa de transmissão foram desenvolvidos para maximizar a e ciência espectral. Para sistemas limitados em potência os transmissores alocam os recursos quer de antenas de transmissão quer de recepção conjuntamente. Os transmissores estão equipados com várias antenas e o processamento de sinal e implementado de modo a eliminar a interferência entre utilizadores. Sistemas de célula única e de múltiplas células foram estudados. Para estes foi considerado o problema da maximização de taxa de transmissão o qual foi resolvido heuristicamente, através do desacoplamento do problema em duas partes, uma onde se efectua a seleção de utilizadores e outra onde se considera a alocação de recursos. A seleção de utilizadores e feita em função do tipo de técnicas de pré-codificação implementadas e do nível de informação que o transmissor possui. Os algoritmos de seleção de utilizadores desenvolvidos verificam a compatibilidade espacial entre utilizadores, usando para tal métricas propostas. Cada uma das métricas oferece um trade-off diferente entre a precisão para identificar um utilizador compatível e a complexidade necessária para a implementar. Foram usadas simulações numéricas para avaliar a performance das técnicas de seleção de utilizadores propostas (métricas e algoritmos), performance que foi comparada com as técnicas mais inovadoras.
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Peel, Christian B. "Studies in multiple-antenna wireless communications /." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd331.pdf.
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El, Effendi M.-Adib. "Performance evaluation of multiple antenna systems." Thesis, The University of Wisconsin - Milwaukee, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550206.
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Wireless traffic is in a continuous increase and there are growing demands for wireless systems that support higher interference suppression and noise mitigation for mobile and cellular communications. Single antenna systems use frequency or time diversity to overcome the multipath fading effect as it represents a major problem that results in sever performance degradation. However, frequency diversity is inefficient in terms of bandwidth requirements and time diversity needs slow time varying channels. Space diversity has been proposed as an alternative to the former schemes where more antennas are added to the transmitter and/or receiver. Nevertheless, when multiple antennas are used; two different gains can be employed to boost system performance represented by the space diversity gains and array gain and it is not yet clear which gain has better performance as most of the published work study each one separately. Further, there is a variety of beamforming algorithms can achieve a high array gain to mitigate noise and interference. However, because each algorithm uses a different approach to achieve this goal, an ambiguity arises in some of their performance aspects as it is possible that some algorithms may have similar performance in interference suppression but varies in their capability in mitigating noise or vice versa. This may have a big impact on their performance in some environments where the interference and noise floors vary considerably and yet no study has fully addressed this problem. In this work, multiple input multiple output antenna systems were investigated using a variety of antenna configurations and algorithms to evaluate their performance under different noise and interference levels using MATLAB software modeling tools. It was found that array gain gives higher system performance in comparison with the space diversity gain and can be considered the most optimal scheme. After analyzing the performance of different beamformers, it was found that phase shift and MVDR beamformers both have the same capability in mitigating white noise while they vary in their ability in interference suppression depending on the level of SINR of the surrounding environment. Also, Frost beamformer shows high interference suppression while its noise mitigation capability is very low which limits its use in applications where the noise floor is higher than the interference floor.
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Peel, Christian Bruce. "Studies in Multiple-Antenna Wireless Communications." BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/119.
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Wireless communications systems are used today in a variety of milieux, with a recurring theme: users and applications regularly require higher throughput. Multiple antennas enable higher throughput and/or more robust performance than single-antenna communications, with no increase in power or frequency bandwidth. Systems are required which achieve the full potential of this "space-time" communication channel under the significant challenges of time-varying fading, multiple users, and the choice of appropriate coding schemes. This dissertation is focused on solutions to these problems. For the single-user case, there are many well-known coding techniques available; in the first part of this dissertation, the performance of two of these methods are analyzed.
Trained and differential modulation are simple coding techniques for single-user time-varying channels. The performance of these coding methods is characterized for a channel having a constant specular component plus a time-varying diffuse component. A first- order auto-regressive model is used to characterize diffuse channel coefficients that vary from symbol to symbol, and is shown to lead to an effective SNR that decreases with time. A lower bound on the capacity of trained modulation is found for the specular/diffuse channel. This bound is maximized over the training length, training frequency, training signal, and training power. Trained modulation is shown to have higher capacity than differential coding, despite the effective SNR penalty of trained modulation versus differential methods.
The second part of the dissertation considers the multi-user, multi-antenna channel, for which capacity-approaching codes were previously unavailable. Precoding with the channel inverse is shown to provide capacity that approaches a constant as the number of users and antennas simultaneously increase. To overcome this limitation, a simple encoding algorithm is introduced that operates close to capacity at sum-rates of tens of bits/channel-use. The algorithm is a variation on channel inversion that regularizes the inverse and uses a "sphere encoder" to perturb the data to reduce the energy of the transmitted signal. Simulation results are presented which support our analysis and algorithm development.
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Raines, Bryan Dennis. "Systematic Design of Multiple Antenna Systems Using Characteristic Modes." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306951104.
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Zhang, Shuai. "Investigating and Enhancing Performance of Multiple Antenna Systems in Compact MIMO/Diversity Terminals." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-116402.
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Today, owners of small communicating device are interested in transmitting or receiving various multimedia data. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diversity/Multiple-Input Multiple-Output (MIMO) techniques can increase wireless channel capacity without the need for additional power or spectrum in rich scattering environments. However, due to the limited space of small mobile devices, the correlation coefficients between MIMO antenna elements are very high and the total efficiencies of MIMO elements degrade severely. Furthermore, the human body causes high losses on electromagnetic wave. During the applications, the presence of users may result in the significant reduction of the antenna total efficiencies and highly affects the correlations of MIMO antenna systems. The aims of this thesis are to investigate and enhance the MIMO/diversity performance of multiple antenna systems in the free space and the presence of users. The background and theory of multiple antenna systems are introduced briefly first. Several figures of merits are provided and discussed to evaluate the multiple antenna systems. The decoupling techniques are investigated in the multiple antenna systems operating at the higher frequencies (above 1.7 GHz) and with high radiation efficiency. The single, dual and wide band isolation enhancements are realized through the half-wavelength decoupling slot, quarter-wavelength decoupling slot with T-shaped impedance transformer, tree-like parasitic element with multiple resonances, as well as the different polarizations and radiation patterns of multiple antennas. In the lower bands (lower than 960 MHz), due to the low radiation efficiency and strong chassis mode, the work mainly focused on how to directly reduce the correlations and enlarge the total efficiency. A new mode of mutual scattering mode is introduced. By increasing the Q factors, the radiation patterns of multiple antennas are separated automatically to reduce the correlations. With the inter-element distance larger than a certain distance, a higher Q factor also improved the total efficiency apart from the low correlation. A wideband LTE MIMO antenna with multiple resonances is proposed in mobile terminals. The high Q factors required for the low correlation and high efficiencies in mutual scattering mode is reduced with another mode of diagonal antenna-chassis mode. Hence, the bandwidth of wideband LTE MIMO antenna with multiple resonances mentioned above can be further enlarged while maintaining the good MIMO/diversity performance. The user effects are studied in different MIMO antenna types, chassis lengths, frequencies, port phases and operating modes. Utilizing these usefully information, an adaptive quad-element MAS has been proposed to reduce the user effects and the some geranial rules not limited to the designed MAS have also been given.QC 20130121
EU Erasmus Mundus External Cooperation Window TANDEM
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McNamara, Darren Phillip. "Characterisation and investigation of multiple-input multiple-output wireless communication channels." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274672.
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Anderson, Adam L. "Unitary space-time transmit diversity for multiple antenna self-interference suppression /." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd500.pdf.
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Adeane, Jaime. "Spatial diversity in wireless communications : multiple antenna systems and virtual antenna arrays." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613069.
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Ayele, Mehari L. "Four-port miniaturized and highly isolated antenna for multiple-input multiple-output communication systems." Thesis, Wichita State University, 2012. http://hdl.handle.net/10057/6118.
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The objective of this paper is to present an efficient miniaturized antenna design and simulation of a highly isolated multi-port micro-strip antenna for multiple-input multiple-output communication (MIMO) systems. Three geometric configurations were proposed and compared to achieve an isolation of as low as –30 dB without affecting the antenna performance greatly. The antenna was designed to operate at a resonance frequency of 2.45 GHz (fc ). Ferrite material beneath each meander structure was used for miniaturization purposes as well as an FR4 substrate with a compact overall area of .75 lambda0 ×.5 lambda0 for a system board, where lambda0 is the free space wavelength. A ground plane with small etched slits was used for isolation purposes. A maximum gain of 4.6 dBi in the azimuthal plane was achieved. Index Terms: MIMO, meander antenna, four-port antenna, defected ground structureThesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science
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Yang, Jingnong. "Channel State Information in Multiple Antenna Systems." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14120.
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In a MIMO system, a transmitter with perfect knowledge of the underlying channel state information (CSI) can achieve a higher channel capacity compared to transmission without CSI. When reciprocity of the wireless channel does not hold, the identification and utilization of partial CSI at the transmitter are important issues.
This thesis is focused on partial CSI acquisition and utilization techniques for MIMO
channels. We propose a feedback algorithm for tracking the dominant channel subspaces for MIMO systems in a continuously time-varying environment. We exploit the correlation between channel states of adjacent time instants and quantize the variation of channel states. Specifically, we model a subspace as one point in a Grassmann manifold, treat the variations in principal right singular subspaces of the channel matrices as a piecewise-geodesic process in the Grassmann manifold, and quantize the velocity matrix of the geodesic.
We design a complexity-constrained MIMO OFDM system where the transmitter has knowledge of channel correlations. The transmitter is constrained to perform at most one inverse Discrete Fourier Transform per OFDM symbol on the average. We show that in the MISO case, time domain beamforming can be used to do two-dimensional eigen-beamforming. For the MIMO case, we derive design criteria for the transmitter beamforming and receiver combining weighting vectors and show some suboptimal solutions.
The feedback channel may have uncertainties such as unexpected delay or error. We consider channel mean feedback with an unknown delay and propose a broadcast approach that is able to adapt to the quality of the feedback.
Having considered CSI feedback problems where the receiver tries to convey its attained
CSI to the transmitter, we turn to noncoherent coding design for fast fading channels, where the receiver does not have reliable CSI. We propose a data-dependent superimposed training scheme to improve the performance of training based codes. The transmitter is equipped with multiple training sequences and dynamically selects a training sequence for each data sequence to minimize channel estimation error. The set of training sequences are optimized to minimize pairwise error probability between codewords.
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Stimming, Christian. "Multiple antenna concepts in OFDM transmission systems." Göttingen Cuvillier, 2009. http://d-nb.info/995846030/04.
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Spyropoulos, Ioannis. "Interference management in multiple-antenna wireless networks." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3378675.
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Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed Oct. 21, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 82-86).
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Subramanian, Srikanth. "A multiple-antenna-multiple-equalizer system for CDMA indoor wireless systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32728.pdf.
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Kang, Heewon. "Multiple antenna systems in a mobile-to-mobile environment." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11172006-173605/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Gordon L. Stuber, Committee Chair ; Guillermo Goldsztein, Committee Member ; Gregory D. Durgin, Committee Member ; John R, Barry, Committee Member ; Mary Ann Ingram, Committee Member.
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Crossley, David, Morrie Drexler, and Al Waterman. "SIMPLIFIED ANTENNA DESIGN FOR TELEMETRY STATIONS." International Foundation for Telemetering, 1985. http://hdl.handle.net/10150/615596.
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International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, NevadaPSL is developing a telemetry antenna intended to avoid the mechanical complexity of traditional parabolic passive monopulse trackers. For a considerable range of reception scenarios, a stationary non-tracking antenna will fill the reception requirement while greatly simplyfing the antenna hardware as compared to mechanical passive trackers. A single, phi-symmetric, shaped-beam antenna provides proper coverage of the test range for multiple airborne targets. This system is not time shared and requires no acquisition time. Approximate azimuth to the target is displayed on a CRT. This paper examines the applicable test scenario and the resulting hardware.
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Robinson, Michael 1982. "Robust minimum variance beamforming with multiple response constraints." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99791.
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Conventional beamformers can be sensitive to mismatches between presumed and actual steering vectors of the signal-of-interest. A recently proposed class of robust beamformers aim to counteract this problem by using a non-attenuation constraint inside a single hypersphere centered at the presumed steering vector of the signal-of-interest. In an effort to strike a balance between robustness to steering vector error and interference-plus-noise suppression, we propose in this manuscript to use multiple concentric hyperspheres instead of one with different degrees of protection in each. We derive several useful properties of this multiply constrained beamformer and use numerical simulations to show that using two constraints yields improved signal-to-interference-plus-noise-ratio compared to one constraint in certain scenarios, particularly at a large input signal-to-noise-ratio.The manuscript also includes an overview of conventional beamforming, the mismatch problem and previously proposed robust beamformers.
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Li, Zhan. "Antenna designs for handset applications multiple antennas integration and interaction with the human head /." Diss., Restricted to subscribing institutions, 2005. http://proquest.umi.com/pqdweb?did=920934001&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Bahceci, Israfil. "Multiple-Input Multiple-Output Wireless Systems: Coding, Distributed Detection and Antenna Selection." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-022321/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.Altunbasak, Yucel, Committee Chair ; Mersereau, Russell M., Committee Member ; Fekri, Faramarz, Committee Member ; Smith, Glenn, Committee Member ; Huo, Xiaoming, Committee Member. Includes bibliographical references.
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Murthy, Chandra Ramabhadra. "Channel estimation and feedback for multiple antenna communication." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3220395.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed September 5, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 158-164).
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Miao, H. (Honglei). "Channel estimation and positioning for multiple antenna systems." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514284113.
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Abstract
The multiple–input multiple–output (MIMO) technique, applying several transmit and receive antennas in wireless communications, has emerged as one of the most prominent technical breakthroughs of the last decade. Wideband MIMO parameter estimation and its applications to the MIMO orthogonal frequency division multiplexing (MIMO–OFDM) channel estimation and mobile positioning are studied in this thesis.
Two practical MIMO channel models, i.e., correlated-receive independent-transmit channel and correlated-transmit-receive channel, and associated space-time parameter estimation algorithms are considered. Thanks to the specified structure of the proposed training signals for multiple transmit antennas, the iterative quadrature maximum likelihood (IQML) algorithm is applied to estimate the time delay and spatial signature for the correlated-receive independent-transmit MIMO channels. For the correlated-transmit-receive MIMO channels, the spatial signature matrix corresponding to a time delay can be further decomposed in such a way that the angle of arrival (AOA) and the angle of departure (AOD) can be estimated simultaneously by the 2-D unitary ESPRIT algorithm. Therefore, the combination of the IQML algorithm and the 2-D unitary ESPRIT algorithm provides a novel solution to jointly estimate the time delay, the AOA and the AOD for the correlated-transmit-receive MIMO channels. It is demonstrated from the numerical examples that the proposed algorithms can obtain good performance at a reasonable cost.
Considering the correlated-receive independent-transmit MIMO channels, channel coefficient estimation for the MIMO–OFDM system is studied. Based on the parameters of the correlated-receive independent-transmit MIMO channels, the channel statistics in terms of the correlation matrix are developed. By virtue of the derived channel statistics, a joint spatial-temporal (JST) filtering based MMSE channel estimator is proposed which takes full advantage of the channel correlation properties. The mean square error (MSE) of the proposed channel estimator is analyzed, and its performance is also demonstrated by Monte Carlo computer simulations. It is shown that the proposed JST minimum mean square error (MMSE) channel estimator outperforms the more conventional temporal MMSE channel estimator in terms of the MSE when the signals in the receive antenna array elements are significantly correlated. The closed form bit error probability of the space-time block coded OFDM system with correlation at the receiver is also developed by taking the channel estimation errors and channel statistics, i.e., correlation at the receiver, into account.
Mobile positioning in the non-line of sight (NLOS) scenarios is studied. With the knowledge of the time delay, the AOA and the AOD associated with each NLOS propagation path, a novel geometric approach is proposed to calculate the MS's position by only exploiting two NLOS paths. On top of this, the least squares and the maximum likelihood (ML) algorithms are developed to utilize multiple NLOS paths to improve the positioning accuracy. Moreover, the ML algorithm is able to estimate the scatterers' positions as well as those of the MSs. The Cramer-Rao lower bound related to the position estimation in the NLOS scenarios is derived. It is shown both analytically and through computer simulations that the proposed algorithms are able to estimate the mobile position only by employing the NLOS paths.
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Bala, Erdem. "Multichannel, multiuser and multiple antenna wireless communication systems." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 184 p, 2007. http://proquest.umi.com/pqdlink?did=1251904851&Fmt=7&clientId=79356&RQT=309&VName=PQD.
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Bergeron-Burns, Philippe. "Reduced complexity decoding for multiple antenna wireless communications." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82467.
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One way to achieve high data rate and bandwidth efficient wireless communications is to employ multiple transmit and receive antennas creating a Multiple-Input Multiple-Output (MIMO) system, combined with Linear Dispersion (LD) codes. Sphere Decoder (SD) is a low complexity Maximum Likelihood (ML) method of decoding LD codes.Using Subspace Matched Filtering principles, two complexity reducing front-ends to any variant of the SD, are developed. These two-stage decoders are designed to only have marginally worse performance than SD.
Computer simulations confirm the lower complexity and close to ML performance of the two-stage decoders. For a two transmit and two receive antenna LD coded MIMO system at an SNR of 22dB, the two-stage decoder reduces the average size of the SD search tree by a factor of 5. The BER performance of the two-stage decoder is within 0.25dB of the ML performance.*
*This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).
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Ng, Kah Heng. "Advanced urban propagation modelling for multiple antenna systems." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424638.
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Govindasamy, Siddhartan 1975. "Multiple-antenna systems in ad-hoc wireless networks." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44410.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (leaves 223-229).
The increasing demand for wireless communication services has resulted in crowding of the electromagnetic spectrum. The "spectral-commons" model, where a portion of the electromagnetic spectrum is public and used on an ad-hoc basis, has been proposed to free up spectrum that has been allocated but underutilized. Ad-hoc wireless networks (networks with no central control) are also interesting in their own right as they do not require costly infrastructure, are robust to single-node failures, and can be deployed in environments where it is difficult to deploy infrastructure. The main contributions of this thesis are expressions for the mean and in some cases the variance of the spectral efficiency (bits/second/Hz) of single-hop links in random wireless networks as a function of the number of antennas per node, link-length, interferer density, and path-loss-exponent (an environmental parameter that determines signal decay with distance), under assumptions chosen for realistic implementability in the near future. These results improve our understanding of such systems as they indicate the data rates achievable as a function of tangible parameters like user density and environmental characteristics, and are useful for designers of wireless networks to trade-off hardware costs, data-rates, and user densities. We found that constant mean spectral efficiencies can be maintained in wireless networks with increasing user density by linearly increasing the number of antenna elements per user, or by maintaining a constant fraction of nodes connected to high capacity infrastructure like optical fiber, equipped with antenna arrays. These are promising ways to serve an increasing density of users without increasing bandwidth. Additionally, several interesting features of such networks have been highlighted.
(cont.) For instance we found that the mean and variance of spectral efficiencies can be characterized in terms of a parameter called the link rank, which on average equals the number of interferers whose signal power is stronger at a representative receiver than its target transmitter. Rank thus combines the effects of node density and link lengths. Another interesting finding is that mean spectral efficiency in networks with rank-1 links, and equal numbers of antennas at transmit and receive sides can be improved if nodes turn off two thirds of their transmit antennas. These results were derived using infinite random matrix theory and validated using Monte Carlo simulations which were also used to characterize the distribution of spectral efficiencies in such networks.
by Siddhartan Govindasamy.
Ph.D.
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Narula, Aradhana. "Information theoretic analysis of multiple-antenna transmission diversity." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10453.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 125-127).
by Aradhana Narula.
Ph.D.
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Hansen, R. C. "A REVIEW OF MULTIPLE BEAM ANTENNA ARRAY TRADEOFFS." International Foundation for Telemetering, 1986. http://hdl.handle.net/10150/615352.
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International Telemetering Conference Proceedings / October 13-16, 1986 / Riviera Hotel, Las Vegas, NevadaTelemetry instrumentation antennas often require several beams to allow simultaneous tracking of several targets. These multiple beams can be provided several ways, including multiple beam antennas and phased arrays. A brief review of the tradeoffs involved in implementing multiple beams with phased arrays is given. Planar arrays, which may be combined to provide wide angular coverage, include a corporate feed giving multiple independent beams, a distributed configuration with independent beams, the Butler beamformer, and the Gent-Rotman beamformer. Conformal implementations include cylindrical and conical arrays, and the spherical dome lens.
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Joudeh, Hamdi. "A rate-splitting approach to multiple-antenna broadcasting." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43930.
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Signal processing techniques for multiple-antenna transmission can exploit the spatial dimension of the wireless channel to serve multiple users simultaneously, achieving high spectral efficiencies. Realizing such gains; however, is strongly dependent on the availability of highly accurate and up-to-date Channel State Information at the Transmitter (CSIT). This stems from the necessity to deal with multiuser interference through preprocessing; as receivers cannot coordinate in general. In wireless systems, CSIT is subject to uncertainty due to estimation and quantization errors, delays and mismatches. This thesis proposes optimized preprocessing techniques for broadcasting scenarios where a multi-antenna transmitter communicates with single-antenna receivers under CSIT uncertainties. First, we consider a scenario where the transmitter communicates an independent message to each receiver. The most popular preprocessing techniques in this setup are based on linear precoding (or beamforming). Despite their near-optimum rate performances when highly accurate CSIT is available, we show that such techniques exhibit severe losses under CSIT uncertainties, even when optimally designed. We depart from this conventional approach and adopt an unorthodox transmission strategy based on Rate-Splitting (RS), which relies on broadcasting a common data stream on top of the private data streams precoded using partial CSIT. We propose an average Weighted Minimum Mean Square Error (WMMSE) algorithm to maximize the ergodic sum-rate performance. While the ergodic sum-rate measure captures the long-term overall performance, it is not well suited for delay-limited or fairness based transmissions. Hence, we generalize the RS strategy to formulate the problem of achieving robust max-min fairness over one random fading state under a bounded CSIT uncertainty model. We derive new performance limits in terms of the symmetric-DoF under heterogeneous CSIT qualities across users to identify the RS gains. Then, a robust WMMSE algorithm based on the cutting-set method is proposed to solve the semi-infinite optimization problem. This framework is extended to address the problem of power minimization under Quality of Service (QoS) constraints. Finally, we consider the problem of achieving max-min fairness in a multigroup multicasting scenario, where each message is intended to a group of users. We assume perfect CSIT in this setup, where the presence of multiple users in each group is thought of as a source of (finite) uncertainty. The DoF performance of conventional beamforming techniques are derived from which their limitations are identified. The RS strategy is then extended to this scenario, where we show that significant DoF gains can be achieved. The RS precoder optimization problem in this setup is then solved using the WMMSE approach.
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Rafati, Hamid Reza. "A new receiver architecture for multiple-antenna systems." Diss., Restricted to subscribing institutions, 2006. http://proquest.umi.com/pqdweb?did=1276402851&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Roh, June Chul. "Multiple-antenna communication systems with finite rate feedback /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3167845.
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Romero, Zurita Leonardo Nabil. "Optimising multiple antenna techniques for physical layer security." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7636/.
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Wireless communications offer data transmission services anywhere and anytime, but with the inevitable cost of introducing major security vulnerabilities. Indeed, an eavesdropper can overhear a message conveyed over the open insecure wireless media putting at risk the confidentiality of the wireless users. Currently, the way to partially prevent eavesdropping attacks is by ciphering the information between the authorised parties through complex cryptographic algorithms. Cryptography operates in the upper layers of the communication model, bit it does not address the security problem where the attack is suffered: at the transmission level. In this context, physical layer security has emerged as a promising framework to prevent eavesdropping attacks at the transmission level. Physical layer security is based on information-theoretic concepts and exploits the randomness and the uniqueness of the wireless channel. In this context, this thesis presents signal processing techniques to secure wireless networks at the physical layer by optimising the use of multiple-antennas. A masked transmission strategy is used to steer the confidential information towards the intended receiver, and, at the same time, broadcast an interfering signal to confuse unknown eavesdroppers. This thesis considers practical issues in multiple-antenna networks such as limited transmission resources and the lack of accurate information between the authorised transmission parties. The worst-case for the security, that occurs when a powerful eavesdropper takes advantage of any opportunity to put at risk the transmission confidentiality, is addressed. The techniques introduced improve the security by offering efficient and innovative transmission solutions to lock the communication at the physical layer. Notably, these transmission mechanisms strike a balance between confidentiality and quality to satisfy the practical requirements of modern wireless networks.
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Coon, Justin Porter. "Frequency-domain equalization of single-carrier transmissions in single-antenna and multiple-antenna systems." Thesis, University of Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419133.
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Glenn, Dickins, and glenn dickins@dolby com. "Applications of Continuous Spatial Models in Multiple Antenna Signal Processing." The Australian National University. Research School of Information Sciences and Engineering, 2008. http://thesis.anu.edu.au./public/adt-ANU20080702.222814.
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This thesis covers the investigation and application of continuous spatial models for multiple antenna signal processing. The use of antenna arrays for advanced sensing and communications systems has been facilitated by the rapid increase in the capabilities of digital signal processing systems. The wireless communications channel will vary across space as different signal paths from the same source combine and interfere. This creates a level of spatial diversity that can be exploited to improve the robustness and overall capacity of the wireless channel. Conventional approaches to using spatial diversity have centered on smart, adaptive antennas and spatial beam forming. Recently, the more general theory of multiple input, multiple output (MIMO) systems has been developed to utilise the independent spatial communication modes offered in a scattering environment.¶
Underlying any multiple antenna system is the basic physics of electromagnetic wave propagation. Whilst a MIMO system may present a set of discrete inputs and outputs, each antenna element must interact with the underlying continuous spatial field. Since an electromagnetic disturbance will propagate through space, the field at different positions in the space will be interrelated. In this way, each position in the field cannot assume an arbitrary independent value and the nature of wave propagation places a constraint on the allowable complexity of a wave-field over space. To take advantage of this underlying physical constraint, it is necessary to have a model that incorporates the continuous nature of the spatial wave-field. ¶This thesis investigates continuous spatial models for the wave-field. The wave equation constraint is introduced by considering a natural basis expansion for the space of physically valid wave-fields. This approach demonstrates that a wave-field over a finite spatial region has an effective finite dimensionality. The optimal basis for representing such a field is dependent on the shape of the region of interest and the angular power distribution of the incident field. By applying the continuous spatial model to the problem of direction of arrival estimation, it is shown that the spatial region occupied by the receiver places a fundamental limit on the number and accuracy with which sources can be resolved. Continuous spatial models also provide a parsimonious representation for modelling the spatial communications channel independent of specific antenna array configurations. The continuous spatial model is also applied to consider limits to the problem of wireless source direction and range localisation.
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Chu, Min. "Phase-shifting techniques for wireless multiple-antenna transmitter applications /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/6002.
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Klenner, Peter [Verfasser]. "Multiple Antenna Doppler-Compensation for OFDM Systems / Peter Klenner." Aachen : Shaker, 2011. http://d-nb.info/1071529552/34.
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Tao, Yuming. "Multiple-beam antenna array for millimeter-wave wireless communications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/NQ39397.pdf.
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Khuon, Lunal. "Parallel integrated receivers for multiple antenna wireless LAN systems." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38689.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 147-154).
This thesis focuses on the design of power- and area-efficient parallel integrated receivers for multiple antenna wireless LAN systems. These receivers are part of an indoor parallel radio system that achieves 1 gigabit per second data rates and enables high bandwidth wireless communication between portable user devices and a high speed wired internet connection. Since a critical aspect for efficiency is that an optimal number of transceivers be used to meet system requirements, this thesis first considers power dissipation and area. consumption for parallel integrated transceivers. It develops parallel transceiver power dissipation and area consumption models that are functions of distance, data rate, and noise figure and incorporate the behavior of a multiple-input, multiple-output channel and power dissipation and area consumption values for typical RF circuits. These models properly balance benefits of multiple antennas with drawbacks due to parallel radio overhead. Their application shows that the combined transceiver power dissipation can actually decrease with more antennas and also provides a circuits-based number of antennas upper bound that has not been established previously.
(cont.) The thesis then proposes a solution that applies multiple antenna signal-to-noise ratio (SNR) gain at the receiver to reduce its power dissipation and area consumption. SNR gain trades noise figure for power- and area-efficient circuits. The implementation of a, single chip 5.22-GHz area-efficient parallel receiver RFIC that shows practical application of these models, SNR gain, and area-efficient circuits is demonstrated. The context of this design comes from the Wireless Gigabit Local Area Network (WiGLAN). It's system characteristics such as a wide 150 MHz bandwidth and parallel radios uniquely determine a WiGLAN parallel receiver design.
by Lunal Khuon.
Ph.D.
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Kwala, Pimpin Carleton University Dissertation Engineering Electrical. "Adaptive multiple-beam antenna arrays for indoor wireless communications." Ottawa, 1992.
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Lee, Heechoon. "On the design of reliable multiple antenna communication systems." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1317343331&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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