Dissertations / Theses on the topic 'Antenna Selection'
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Al-Shuraifi, Mohammed. "Transmit antenna selection and user selection in multiuser MIMO downlink systems." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13271.
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Multiuser multiple input multiple output (MU-MIMO) systems play essential role in improving throughput performance and link reliability in wireless communications. This improvement can be achieved by exploiting the spatial domain and without the need of additional power and bandwidth. In this thesis, three main issues which are of importance to the data rate transmission have been investigated. Firstly, antenna selection in MU-MIMO downlink systems has been considered, where this technique can be e fficiently used to reduce the complexity and cost caused by radio frequency chains, associated with antennas, while keeping most of the diversity advantages of the system. We proposed a transmit antenna selection algorithm which can select an optimal set of antennas for transmission in descending order depending on the product of eigenvalues of users' effective channels. The capacity achieved by the proposed algorithm is about 99:6% of the capacity of the optimum search method, with much lower complexity. Secondly, user selection technology in MU-MIMO downlink systems has been studied. Based on the QR decomposition, we proposed a greedy suboptimal user selection algorithm which adopts the product of singular values of users' effective channels as a selection metric. The performance achieved by the proposed algorithm is identical to that of the capacity-based algorithm, with significant reduction in complexity. Finally, a proportional fairness scheduling algorithm for MU-MIMO downlink systems has been proposed. By utilising the upper triangular matrix obtained by applying the QRD on the users' effective channel matrices, two selection metrics have been proposed to achieve the scheduling process. The first metric is based on the maximum entry of the upper triangular matrix, while the second metric is designed using the ratio between the maximum and minimum entries of the triangular matrix multiplied by the product of singular values of effective channels. The two metric provide significant degrees of fairness. For each of these three issues, a different precoding method has been used in order to cancel the interuser interference before starting the selection process. This allows to investigate each precoding design separately and to evaluate the computational burden required for each design.
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Husbands, Ryan R. "Transmit antenna selection for multiuser massive MIMO." Thesis, University of Kent, 2018. https://kar.kent.ac.uk/69467/.
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In massive multiple input multiple output (MIMO) systems, major challenges are present due to the large number of active antennas and radio frequency (RF) chains,suchasincreasedpowerconsumptionandcomputationcomplexity. Transmitantennaselection(TAS)isbeinginvestigatedasasolutiontotacklethesechallenges. In this thesis, a dynamic transmit antenna selection technique is proposed whichcanmaximizethesumrateofamultiuser(MU)-MIMOcommunicationsystem. In order to satisfy the objective, the number of transmit antennas required is determined by remodeling it as a binary Knapsack Problem (KP) and then extending to a Multiple KP (MKP) for MU-MIMO. Furthermore, an improvement in the decision making is also proposed with the introduction of a flexible decision criteria, whilst reducing the structure of the MKP to resemble that of a single binary KP. Additionally, comparisons of the KP based algorithms are done with two low complexity techniques, which are the sequential selection algorithm and random selection algorithm. Results show that the KP based techniques outperform these low complexity techniques. The modified binary KP algorithm is also superior to that of the MKP, as it is not sensitive to solving as binary knapsack sub-problems. The proposed technique has good performance for different antenna selection measures and is suitable to ensure communication efficiency in future wireless communication systems.
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Hugine, Akilah L. "Antenna Selection for a Public Safety Cognitive Radio." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/32577.
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Ever since the dawn of radio communication systems, the antenna has been the key component in the construction and performance of every wireless system. With the proliferation of new radio systems, a cognitive radio is a radio that has the capability to sense, learn, and autonomously adapt to its environment. The hardware components are essential to optimizing performance. Antenna hardware for cognitive radio applications presents distinctive problems, since in theoretical terms, a cognitive radio can operate anywhere in the spectrum.
The purpose of this thesis is to investigate a particular type of cognitive radio system and examine the potential affects the antenna will have on the system. The thesis will provide an overview of fundamental antenna properties, the performance characteristics of the particular antenna used in this research, and the system characteristics when the antenna is integrated. This thesis will also illustrate how the antenna and its properties affect the overall public safety cognitive radio performance. This information can be used to establish antenna selection criteria for optimum system performance.Master of Science
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Lupupa, Mzabalazo. "Transmit antenna selection in fading wireless communication systems." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/12110.
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Includes abstract.Includes bibliographical references (leaves 79-83).
To address the drawbacks associated with multiple-input multiple-output (MIMO) systems, we propose the use of the transmit antenna selection technique. In transmit antenna selection, the best performing antenna(s) is selected from all the available transmit antennas for transmission. Transmit antenna selection reduces the number of radio frequency chains, and the system complexity while still achieving the goals of multiple antenna systems. In this thesis the performance of a MIMO system employing transmit antenna selection and maximal-ratiocombining is studied.
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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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PEREZ, DAILYS ARRONDE. "ANTENNA SELECTION IN THE DOWNLINK OF PRECODED MULTIUSER MIMO SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36056@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Esta dissertação enfoca o enlace direto de sistemas MIMO multiusuário com pré-codificação onde a estação base e os terminais dos usuários possuem múltiplas antenas mas transmitem e recebem, respectivamente, símbolos de informação através de subconjuntos selecionados de seus conjuntos de antenas. O trabalho considera sistemas que utilizam técnicas de précodificação linear como Zero Forcing (ZF) e Minimum Mean Square Error (MMSE). Expressões gerais que descrevem os sistemas e relacionam a energia gasta na transmissão com a energia disponível para a detecção em cada usuário são apresentadas. Com base nestas relações, um procedimento para seleção de antenas na transmissão é proposto visando a minimização da probabilidade de erro. Um algoritmo de busca não exaustiva denominado ITES (Iterative Search) foi desenvolvido e testado e mostrou-se capaz de, com apenas uma pequena fração do esforço computacional, fornecer um desempenho próximo ao da seleção ótima, que demanda uma busca exaustiva. A seleção de antenas na recepção é também efetuada usando um critério de otimização semelhante. O caso geral da seleção conjunta de antenas na transmissão e na recepção contempla a combinação de ambas estratégias, resultando na redução da complexidade tanto na estação base, quanto nos terminais dos usuários. Os resultados de desempenho em termos da taxa de erro de bit, obtidos por meio de simulações e abordagem semianalítica, são apresentados para diferentes cenários.
This thesis focuses on the downlink of a multiuser multiple-input multiple-output (MU-MIMO) systems where the Base Station (BS) and the users stations (UEs) transmit and receive information symbols, respectively, by selected subset of their antennas. The performance of the system is evaluated employing linear precoding techniques as Zero Forcing (ZF) and Minimum Mean Square Error (MMSE). A general model to describe the system and expressions that relate the energy spent in transmission with the energy available for detection at each user are presented. A transmit antenna selection procedure is proposed aiming at the minimization of the detection error probability. A suboptimal search algorithm, called ITES (Iterative Search), able to deliver a performance close to the one resulting from the optimal exhaustive search selection is also proposed. The receive antenna selection is also performed using a similar optimization criterion. Joint antennas selection at the transmitter and receiver contemplates the efficient combination of both strategies, leading to a complexity reduction in BS and UEs. BER performance results, obtained via simulation and semi-analytical approaches, are presented for different scenarios.
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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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Morris, Matthew Leon. "The Impact of Antenna and RF System Characteristics on MIMO System Capacity." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd978.pdf.
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Zhou, Zhenxiang. "Performance analysis and tracking for multibeam selection antenna array system in mobile communication." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/MQ51520.pdf.
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Jang, Dhong Woon. "A 3D LINK ANALYSIS AND SELECTION OF A RECEIVE ANTENNA ANGLE IN TELEMETRY SYSTEMS." International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/606362.
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International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, CaliforniaA three dimension (3D) link analysis is performed considering multipath effects caused by a reflected signal and the difference angle between the antenna bore-sight and Line-Of-Sight (LOS). In addition, a direction of a receive antenna is determined for a receiver to get maximum signal strength in a telemetry situation. For a fixed receive antenna, the angle is determined to maximize the average Carrier to Noise Ratio (CNR) over the interested part of a trajectory. For a tracking antenna, the angle at every position is selected to give maximum CNR or to direct the boresight to the flying projectile.
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Okumu, Elizabeth Mukhwana. "Performance evaluation of cross-layer energy-efficient transmit antenna selection for spatial multiplexing systems." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28111.
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Abstract Multiple-input multiple-output (MIMO) and cognitive radio (CR) are key techniques for present and future high-speed wireless technologies. On the other hand, there are rising energy costs and greenhouse emissions associated with the provision of high-speed wireless communications. Consequently, the design of high-speed energy efficient systems is paramount for next-generation wireless systems. This thesis studies energy-efficient antenna selection for spatial multiplexing multiple-antenna systems from a cross-layer perspective, contrary to the norm, where physical-layer energy efficiency metrics are optimized. The enhanced system performance achieved by cross-layer designs in wireless networks motivates this research. The aim of the thesis is to propose and analyze novel cross-layer energy-efficient transmit antenna selection schemes that enhance energy efficiency and system performance - with regard to throughput, transmission latency, packet error rate and receiver buffer requirements. Firstly, this thesis derives the analytical expression for data link throughput for point-to-point spatial multiplexing multiple-antenna systems - which include MIMO and underlay CR MIMO systems - equipped with linear receivers with N-process stop-and-wait (N-SAW) as the automatic repeat request (ARQ) protocol. The performance of cross-layer transmit antenna selection, which maximizes the derived throughput metric, is then analyzed. The impact of packet size, number of SAW processes and the stalling of packets inside the receiver reordering buffer is considered in the investigation. The results show that the cross-layer approach, which takes into account system characteristics at both the data link and physical layers, has superior performance in comparison with the conventional physical-layer approach, which optimizes capacity. Secondly, this thesis proposes a cross-layer energy efficiency metric, based on the derived system throughput. Energy-efficient transmit antenna selection for spatial multiplexing MIMO systems, which maximizes the proposed cross-layer energy efficiency metric, by jointly optimizing the transmit antenna subset and transmit power, subject to spectral efficiency and transmit power constraints, is then introduced and analyzed. Additionally, adaptive modulation is incorporated into the proposed cross-layer scheme to enhance system performance. Cross-layer energyefficient transmit antenna selection for underlay CR MIMO systems, where interference constraints now come into play, is then considered. Lastly, this thesis develops novel reduced complexity versions of the proposed cross-layer energyefficient transmit antenna selection schemes - along with detailed complexity analysis - which shows that the proposed cross-layer approach attains significant energy efficiency and performance gains at affordable computational complexity.
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Anreddy, Vikram R. "Indoor MIMO Channels with Polarization Diversity: Measurements and Performance Analysis." Thesis, Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04112006-093641/.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.Ingram Mary Ann, Committee Chair ; Durgin, Gregory David, Committee Member ; Williams, Douglas B, Committee Member.
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JAIN, VISHESH. "PERFORMANCE ANALYSIS OF GENERALIZED SELECTION COMBINING IN ARBITRARILY CORRELATED NAKAGAMI FADING CHANNELS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1131175492.
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Ge, Lu. "Distributed space-time coding, including the Golden Code, with application in cooperative networks." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17052.
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This thesis presents new methodologies to improve performance of wireless cooperative networks using the Golden Code. As a form of space-time coding, the Golden Code can achieve diversity-multiplexing tradeoff and the data rate can be twice that of the Alamouti code. In practice, however, asynchronism between relay nodes may reduce performance and channel quality can be degraded from certain antennas. Firstly, a simple offset transmission scheme, which employs full interference cancellation (FIC) and orthogonal frequency division multiplexing (OFDM), is enhanced through the use of four relay nodes and receiver processing to mitigate asynchronism. Then, the potential reduction in diversity gain due to the dependent channel matrix elements in the distributed Golden Code transmission, and the rate penalty of multihop transmission, are mitigated by relay selection based on two-way transmission. The Golden Code is also implemented in an asynchronous one-way relay network over frequency flat and selective channels, and a simple approach to overcome asynchronism is proposed. In one-way communication with computationally efficient sphere decoding, the maximum of the channel parameter means is shown to achieve the best performance for the relay selection through bit error rate simulations. Secondly, to reduce the cost of hardware when multiple antennas are available in a cooperative network, multi-antenna selection is exploited. In this context, maximum-sum transmit antenna selection is proposed. End-to-end signal-to-noise ratio (SNR) is calculated and outage probability analysis is performed when the links are modelled as Rayleigh fading frequency flat channels. The numerical results support the analysis and for a MIMO system maximum-sum selection is shown to outperform maximum-minimum selection. Additionally, pairwise error probability (PEP) analysis is performed for maximum-sum transmit antenna selection with the Golden Code and the diversity order is obtained. Finally, with the assumption of fibre-connected multiple antennas with finite buffers, multiple-antenna selection is implemented on the basis of maximum-sum antenna selection. Frequency flat Rayleigh fading channels are assumed together with a decode and forward transmission scheme. Outage probability analysis is performed by exploiting the steady-state stationarity of a Markov Chain model.
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Challita, Frédéric. "Massive MIMO channel characterization and propagation-based antenna selection strategies : application to 5G and industry 4.0." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I043/document.
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Dans le domaine des télécommunications sans fil, les domaines applicatifs sont de plus en plus larges, s’étendant par exemple du grand public, à la voiture connectée, à l’internet des objets (IoT Internet of Things) et à l’industrie 4.0. Dans ce dernier cas, l’objectif est d’aboutir à une flexibilité et à une versatilité accrues des chaînes de production et à une maintenance prédictive des machines, pour ne citer que quelques exemples. Cependant, les réseaux sans fil actuels ne sont pas encore en mesure de répondre aux nombreuses lacunes de la quatrième génération des réseaux mobiles (4G) et aux exigences de la 5G quant à une connectivité massive, une ultra fiabilité et des temps de latence extrêmement faibles. L’optimisation des ressources spectrales est également un point très important. La 5G était initialement considérée comme une évolution, rendue possible grâce aux améliorations apportées à la LTE (Long Term Evolution), mais elle ne tardera pas à devenir une révolution et une avancée majeure par rapport aux générations précédentes.Dans ce cadre, la technologie des réseaux massifs ou Massive MIMO (Multiple-Input Multiple-Output) s’est imposée comme l’une des technologies de couche physique les plus prometteuses. L'idée principale est d'équiper les stations de base de grands réseaux d’antennes (100 ou plus) pour communiquer simultanément avec de nombreux terminaux ou équipements d’utilisateurs. Grâce à un prétraitement intelligent au niveau des signaux d’émission, les systèmes Massive MIMO promettent d’apporter une grande amélioration des performances, tout en assurant une excellente efficacité spectrale et énergétique. Cependant certains défis doivent encore être relevés avant le déploiement complet des communications basées sur le massive MIMO. Par exemple, l’élaboration de modèles de canaux représentatifs de l’environnement réel, l'impact de la diversité de polarisation, les stratégies de sélection optimale d’antennes et l'acquisition d'informations d'état du canal, sont des sujets importants à explorer. En outre, une bonne compréhension des canaux de propagation en milieu industriel est nécessaire pour optimiser les liens de communication de l'industrie intelligente du futur.Dans cette thèse, nous essayons de répondre à certaines de ces questions en nous concentrant sur trois axes principaux :1) La caractérisation polarimétrique des canaux massive MIMO en environnement industriel. Pour cela, on étudie des scénarios correspondant à des canaux ayant ou non une visibilité directe entre émetteur et récepteur (Line of Sight – LOS) ou Non LOS, et en présence de divers types d’obstacles. Les métriques associées sont soit celles utilisées en propagation telles que le facteur de Rice et la corrélation spatiale, soit orientées système comme la capacité totale du canal incluant des stratégies de précodage linéaire. De plus, les schémas de diversité de polarisation proposés montrent des résultats très prometteurs.2) En massive MIMO, un objectif important est de réduire le nombre de chaînes de fréquences radio et donc la complexité du système, en sélectionnant un ensemble d'antennes distribuées. Cette stratégie de sélection utilisant la corrélation spatiale du récepteur et une métrique de propagation comme facteur de mérite, permet d'obtenir une capacité totale quasi-optimale.3) Une technique efficace de réduction des ressources lors de l’acquisition d’informations du canal de propagation dans les systèmes FDD (frequency-division-duplex) est enfin proposée. Elle repose sur la corrélation spatiale au niveau de l'émetteur et consiste à résoudre un ensemble d'équations auto-régressives simples. Les résultats montrent que cette technique permet d’atteindre des performances qui ne sont pas trop éloignées de celles des systèmes TDD (time-division-duplex) initialement proposés pour le massive MIMOContinuous efforts have been made to boost wireless systems performance, however, current wireless networks are not yet able to fulfill the many gaps from 4G and requirements for 5G. Thus, significant technological breakthroughs are still required to strengthen wireless networks. For instance, in order to provide higher data rates and accommodate many types of equipment, more spectrum resources are needed and the currently used spectrum requires to be efficiently utilized. 5G, or the fifth generation of mobile networks, is initially being labeled as an evolution, made available through improvements in LTE, but it will not be long before it becomes a revolution and a major step-up from previous generations. Massive MIMO has emerged as one of the most promising physical-layer technologies for future 5G wireless systems. The main idea is to equip base stations with large arrays (100 antennas or more) to simultaneously communicate with many terminals or user equipments. Using smart pre-processing at the array, massive MIMO promises to deliver superior system improvement with improved spectral efficiency, achieved by spatial multiplexing and better energy efficiency, exploiting array gain and reducing the radiated power. Massive MIMO can fill the gap for many requirements in 5G use-cases notably industrial IOT (internet of things) in terms of data rates, spectral and energy efficiency, reliable communication, optimal beamforming, linear processing schemes and so on. However, the hardware and software complexity arising from the sheer number of radio frequency chains is a bottleneck and some challenges are still to be tackled before the full operational deployment of massive MIMO. For instance, reliable channel models, impact of polarization diversity, optimal antenna selection strategies, mutual coupling and channel state information acquisition amongst other aspects, are all important questions worth exploring. Also, a good understanding of industrial channels is needed to bring the smart industry of the future ever closer.In this thesis, we try to address some of these questions based on radio channel data from a measurement campaign in an industrial scenario using a massive MIMO setup. The thesis' main objectives are threefold: 1) Characterization of massive MIMO channels in Industry 4.0 (industrial IoT) with a focus on spatial correlation, classification and impact of cross-polarization at transmission side. The setup consists in multiple distributed user-equipments in many propagation conditions. This study is based on propagation-based metrics such as Ricean factor, correlation, etc. and system-oriented metrics such as sum-rate capacity with linear precoding and power allocation strategies. Moreover, polarization diversity schemes are proposed and were shown to achieve very promising results with simple allocation strategies. This work provides comprehensive insights on radio channels in Industry 4.0 capable of filling the gap in channel models and efficient strategies to optimize massive MIMO setups. 2) Proposition of antenna selection strategies using the receiver spatial correlation, a propagation metric, as a figure of merit. The goal is to reduce the number of radio frequency chain and thus the system complexity by selecting a set of distributed antennas. The proposed strategy achieves near-optimal sum-rate capacity with less radio frequency chains. This is critical for massive MIMO systems if complexity and cost are to be reduced. 3) Proposition of an efficient strategy for overhead reduction in channel state information acquisition of FDD (frequency-division-duplex) systems. The strategy relies on spatial correlation at the transmitter and consists in solving a set of simple autoregressive equations (Yule-Walker equations). The results show that the proposed strategy achieves a large fraction of the performance of TDD (time-division-duplex) systems initially proposed for massive MIMO
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Zhang, Xi. "Transceiver Design for Multiple Antenna Communication Systems with Imperfect Channel State Information." Doctoral thesis, Stockholm : Elektrotekniska system, Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4679.
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Yu, Yuehua. "Non-Orthogonal Transmission for Future Wireless Communication Systems." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18172.
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The 5G networks are envisioned to support large data traffic, massive connectivity, and ultra low-latency communications. This thesis focuses on the low-complexity design and performance analysis of non-orthogonal transmissions, which is one of the potential candidates to address the aforementioned challenges. We first develop a low-complexity transceiver design for massive MIMO channels. By exploring a sparse representation of the MIMO channel in the virtual angular domain, we generate a set of transmit-receive beam pairs to support the transmission of multiple data streams. These data streams can be easily separated via SIC, and the power allocation is optimized with water-filling. The near-optimal DoF and capacity achieved by the proposed approach are analysed. Next, we investigate the joint antenna selection (AS) problem for MIMO TWRNs. Two near-optimal algorithms, namely the joint relay-source AS (JRSAS) and the separated relay-source AS (SRSAS), are proposed in a greedy manner. Numerical results show that both JRSAS and SRSAS can approach the optimal AS algorithm but with much lower computational complexity. Subsequently, we extend the joint AS problem to a MIMO NOMA system. For the rate-adaptive NOMA, the throughput-oriented AS algorithms are first proposed. For the fixed-rate NOMA, the outage-oriented AS approaches are then developed. The average capacity and outage performance of the proposed algorithms are analysed and compared to the OMA counterparts. By naturally integrating the short-packet and NOMA techniques, we finally investigate the potential ability of short-packet communications using NOMA to fulfil low-latency transmission. For a given set of reliability constraints of users, the transmission latency of a fundamental two-user model is first studied, which is followed by a more practical multi-user system. Numerical results demonstrate the superior performance of NOMA in reducing physical-layer transmission latency in short-packet communications.
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Hanif, Muhammad Fainan. "Aspects of Design and Analysis of Cognitive Radios and Networks." Thesis, University of Canterbury. Department of Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/5072.
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Recent survey campaigns have shown a tremendous under utilization of the bandwidth allocated to various wireless services. Motivated by this and the ever increasing demand for wireless applications, the concept of cognitive radio (CR) systems has rendered hope to end the so called spectrum scarcity. This thesis presents various different facets related to the design and analysis of CR systems in a unified way. We begin the thesis by presenting an information theoretic study of cognitive systems working in the so called low interference regime of the overlay mode. We show that as long as the coverage area of a CR is less than that of a primary user (PU) device, the probability of the cognitive terminal inflicting small interference at
the PU is overwhelmingly high. We have also analyzed the effect of a key parameter governing the amount of power allocated to relaying the PU message in the overlay mode of operation in realistic environments by presenting a simple and accurate approximation. Then, we explore the possibilities of statistical modeling of the cumulative
interference due to multiple interfering CRs. We show that although it is possible to obtain a closed form expression for such an interference due a single CR, the problem is particularly difficult when it comes to the total CR interference in lognormally faded environments. In particular, we have demonstrated that fitting a
two or three parameter lognormal is not a feasible option for all scenarios. We also explore the second-order characteristics of the cumulative interference by evaluating
its level crossing rate (LCR) and average exceedance duration (AED) in Rayleigh and Rician channel conditions. We show that the LCRs in both these cases can be evaluated by modeling the interference process with gamma and noncentral χ2 processes, respectively. By exploiting radio environment map (REM) information, we have presented two CR scheduling schemes and compared their performance with the naive primary exclusion zone (PEZ) technique. The results demonstrate the significance of using an intelligent allocation method to reap the benefits of the tremendous information available to exploit in the REM based methods. At this juncture, we divert our attention to multiple-input multiple-output (MIMO) CR systems operating in the underlay mode. Using an antenna selection philosophy, we solve a convex optimization problem accomplishing the task and show via analysis and simulations that antenna selection can be a viable option for CRs operating in relatively sparse PU environments. Finally, we study the impact of imperfect
channel state information (CSI) on the downlink of an underlay multiple antenna CR network designed to achieve signal-to-interference-plus-noise ratio (SINR) fairness
among the CR terminals. By employing a newly developed convex iteration technique, we solve the relevant optimization problem exactly without performing any relaxation on the variables involved.
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Gao, Yuan [Verfasser], and Klaus [Akademischer Betreuer] Solbach. "Low RF-complexity massive MIMO systems : antenna selection and hybrid analog-digital beamforming / Yuan Gao ; Betreuer: Klaus Solbach." Duisburg, 2017. http://d-nb.info/1142113604/34.
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Aldosari, Mansour. "Design and analysis of green mobile communication networks." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/design-and-analysis-of-green-mobile-communication-networks(37b5278a-45da-4a81-b89c-54c7d876586a).html.
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Increasing energy consumption is a result of the rapid growth in cellular communication technologies and a massive increase in the number of mobile terminals (MTs) and communication sites. In cellular communication networks, energy efficiency (EE) and spectral efficiency (SE) are two of the most important criteria employed to evaluate the performance of networks. A compromise between these two conflicting criteria is therefore required, in order to achieve the best cellular network performance. Fractional frequency reuse (FFR), classed as either strict FFR or soft frequency reuse (SFR), is an intercell interference coordination (ICIC) technique applied to manage interference when more spectrum is used, and to enhance the EE. A conventional cellular model's downlink is designed as a reference in the presence of inter-cell interference (ICI) and a general fading environment. Energy-efficient cellular models,such as cell zooming, cooperative BSs and relaying models are designed, analysed and compared with the reference model, in order to reduce network energy consumption without degrading the SE. New mathematical models are derived herein to design a distributed antenna system (DAS), in order to enhance the system's EE and SE. DAS is designed in the presence of ICI and composite fading and shadowing with FFR. A coordinate multi-point (CoMP) technique is applied, using maximum ratio transmission (MRT) to serve the mobile terminal (MT), with all distributed antenna elements (DAEs), transmit antenna selection (TAS) being applied to select the best DAE and general selection combining (GSC) being applied to select more than one DAE. Furthermore, a Cloud radio access network (C-RAN) is designed and analysed with two different schemes, using the high-power node (HPN) and a remote radio head (RRH), in order to improve the EE and SE of the system. Finally, a trade-off between the two conflicting criteria, EE and SE, is handled carefully in this thesis, in order to ensure a green cellular communication network.
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Chi, Zhanjiang. "Performance Analysis of Maximal-Ratio Combining and Space-Time Block Codes with Transmit Antenna Selection over Nakagami-m Fading Channels." Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/2012.
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The latest wireless communication techniques such as highspeed wireless internet application demand higher data rates and better quality of service (QoS). However, transmission reliability is still degraded by harsh propagation channels. Multiple-input multiple-output (MIMO) systems can increase the system capacity and improve transmission reliability. By transmitting multiple copies of data, a MIMO system can effectively combat the effects of fading. Due to the high hardware cost of a MIMO system, antenna selection techniques have been applied in MIMO system design to reduce the system complexity and cost. The Nakagami-m distribution has been considered for MIMO channel modeling since a wide range of fading channels, from severe to moderate, can be modeled by using Nakagami-m distribution. The Rayleigh distribution is a special case of the Nakagami-m distribution. In this thesis, we analyze the error performance of two MIMO schemes: maximal-ratio combining with transmit antenna selection (the TAS/MRC scheme) and space-time block codes with transmit antenna selection (the TAS/STBC scheme) over Nakagami-m fading channels. In the TAS/MRC scheme, one of multiple transmit antennas, which maximizes the total received signal-to-noise ratio (SNR), is selected for uncoded data transmission. First we use a moment generating function based (MGF-based) approach to derive the bit error rate (BER) expressions for binary phase shift keying (BPSK), the symbol error rate (SER) expressions for M-ray phase shift keying (MPSK) and M-ray quadrature amplitude modulation (MQAM) of the TAS/MRC scheme over Nakagami-m fading channels with arbitrary and integer fading parameters m. The asymptotic performance is also investigated. It is revealed that the asymptotic diversity order is equal to the product of the Nakagami fading parameter m, the number of transmit antenna Lt and the number of receive antenna Lr as if all transmit antenna were used. Then a Gaussian Q-functions approach is used to investigate the error performance of the TAS/STBC scheme over Nakagami-m fading channels. In the TAS/STBC scheme, two transmit antennas, which maximize the output SNR, are selected for transmission. The exact and asymptotic BER expressions for BPSK are obtained for the TAS/STBC schemes with three and four transmit antennas. It is shown that the TAS/STBC scheme can provide a full diversity order of mLtLr.
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Chi, Zhanjiang. "Performance Analysis of Maximal-Ratio Combining and Space-Time Block Codes with Transmit Antenna Selection over Nakagami-m Fading Channels." School of Electrical and Information Engineering, 2007. http://hdl.handle.net/2123/2012.
Full textAbstract:
Master of Engineering (Research)The latest wireless communication techniques such as highspeed wireless internet application demand higher data rates and better quality of service (QoS). However, transmission reliability is still degraded by harsh propagation channels. Multiple-input multiple-output (MIMO) systems can increase the system capacity and improve transmission reliability. By transmitting multiple copies of data, a MIMO system can effectively combat the effects of fading. Due to the high hardware cost of a MIMO system, antenna selection techniques have been applied in MIMO system design to reduce the system complexity and cost. The Nakagami-m distribution has been considered for MIMO channel modeling since a wide range of fading channels, from severe to moderate, can be modeled by using Nakagami-m distribution. The Rayleigh distribution is a special case of the Nakagami-m distribution. In this thesis, we analyze the error performance of two MIMO schemes: maximal-ratio combining with transmit antenna selection (the TAS/MRC scheme) and space-time block codes with transmit antenna selection (the TAS/STBC scheme) over Nakagami-m fading channels. In the TAS/MRC scheme, one of multiple transmit antennas, which maximizes the total received signal-to-noise ratio (SNR), is selected for uncoded data transmission. First we use a moment generating function based (MGF-based) approach to derive the bit error rate (BER) expressions for binary phase shift keying (BPSK), the symbol error rate (SER) expressions for M-ray phase shift keying (MPSK) and M-ray quadrature amplitude modulation (MQAM) of the TAS/MRC scheme over Nakagami-m fading channels with arbitrary and integer fading parameters m. The asymptotic performance is also investigated. It is revealed that the asymptotic diversity order is equal to the product of the Nakagami fading parameter m, the number of transmit antenna Lt and the number of receive antenna Lr as if all transmit antenna were used. Then a Gaussian Q-functions approach is used to investigate the error performance of the TAS/STBC scheme over Nakagami-m fading channels. In the TAS/STBC scheme, two transmit antennas, which maximize the output SNR, are selected for transmission. The exact and asymptotic BER expressions for BPSK are obtained for the TAS/STBC schemes with three and four transmit antennas. It is shown that the TAS/STBC scheme can provide a full diversity order of mLtLr.
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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.
Full textAbstract:
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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Liu, Yi. "The performance of future wireless communication systems." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:a2f0b75e-3b0d-406e-af1b-6c5038c18fae.
Full textAbstract:
Multimedia services provided through wireless networks, such as mobile television and video calls, have recently attracted great attention. These systems require higher data rates, better communication quality, and wider channel bandwidth compared with traditional wireless network services, such as voice calling and text messaging. In response to these demands, multiple-input multiple-output (MIMO) employing multiple antennas at both transmitter and receiver, has been investigated in recent years. Nevertheless, the major impediment in MIMO based wireless systems is the cost of the hardware due to the requirement of the complete radio frequency (RF) chain for each transmit and receive path. One technique named antenna subset selection has been proposed which can reduce the hardware complexity, for example, provide and smaller number of RF chains which are reconfigurable to serve multiple antennas, but retain good communication performance, such as increasing data rates and improving communication quality. On the other hand, network service providers have in recent years established wideband communication systems in order to provide more services and higher bandwidth to customers. However, this development lowers the communication link quality, since signals transmitted in wideband communication systems suffer frequency-selective fading. In order to reduce the fading, orthogonal frequency division multiplexing (OFDM) as a potential infrastructure in the fourth generation mobile communication networks is developed. Referring to the cost-performance ratio, an attractive future wireless system named antenna selection based MIMO-OFDM is considered to be widely utilized in civil wireless communications in near future. The working theory of antenna selection based MIMO-OFDM systems can be simply represented as that a data stream at each selected transmit/receiver antenna is sent/receive over a number of narrow band orthogonal subcarriers. This thesis addresses analysis of wireless channel and performance investigation of future wireless communication systems, such as MIMO and OFDM structures. Moreover, a novel significantly low computational complexity algorithm is introduced in this thesis, which is proposed for antenna selection MIMO-OFDM systems on the basis of multiple selection criteria. It is shown that the proposed selection algorithm clearly reduces the computational complexity load of the selection process and efficiently selects the optimum antenna subset of antenna selection MIMO-OFDM systems. The thesis concludes by outlining the advantage of the proposed antenna selection technique and points out its potential role in future wireless communications.
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Bharadwaj, Vivek. "Ultra-Wideband for Communications: Spatial Characteristics and Interference Suppression." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33183.
Full textAbstract:
Ultra-Wideband Communication is increasingly being considered as an attractive solution for high data rate short range wireless and position location applications. Knowledge of the statistical nature of the channel is necessary to design wireless systems that provide optimum performance. This thesis investigates the spatial characteristics of the channel based on measurements conducted using UWB pulses in an indoor office environment. The statistics of the received signal energy illustrate the low spatial fading of UWB signals. The distribution of the Angle of arrival (AOA) of the multipath components is obtained using a two-dimensional deconvolution algorithm called the Sensor-CLEAN algorithm. A spatial channel model that incorporates the spatial and temporal features of the channel is developed based on the AOA statistics. The performance of the Sensor-CLEAN algorithm is evaluated briefly by application to known artificial channels.
UWB systems co-exist with narrowband and other wideband systems. Even though they enjoy the advantage of processing gain (the ratio of bandwidth to data rate) the low energy per pulse may cause these narrow band interferers (NBI) to severely degrade the UWB system's performance. A technique to suppress NBI using multiple antennas is presented in this thesis which exploits the spatial fading characteristics. This method exploits the vast difference in fading characteristics between UWB signals and NBI by implementing a simple selection diversity scheme. It is shown that this simple scheme can provide strong benefits in performance.Master of Science
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Dietze, Kai. "Analysis of a Two-Branch Maximal Ratio and Selection Diversity System with Unequal Branch Powers and Correlated Inputs for a Rayleigh Fading Channel." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32412.
Full textAbstract:
This report, presents an analytical framework for analyzing two-branch diversity systems for a Rayleigh fading channel. In many cases the fading received at both branches (i.e. a two-antenna element system) is correlated because of the proximity of the antenna elements to each other. It is also not uncommon for a diversity system to use antennas with different patterns or polarizations, this usually results in differences in average signal-to-noise ratios at both branches depending on which element is better matched to the signal environment. As will be shown, the performance of a diversity system depends greatly on the envelope correlation, average power imbalance and the combining scheme used on both branches.
An analytical expression for the probability density function of the signal-to-noise ratio at the output of a two-branch maximal ratio and selection diversity system is developed in this report. The two branches are assumed to be Rayleigh fading, correlated, as well as of unequal signal-to-noise ratios. Measurements were made in Rayleigh fading channels and compared to the analytical results. The analytical cumulative distribution functions (derived using probability distributions) were found to be within 1 dB of the measured results (statistics obtained from time combining) for both maximal ratio and selection diversity attesting to the validity of the analytic results. Also developed in this report are the exact analytical average probabilities of symbol error for coherent BPSK and coherent QPSK before and after maximal ratio combining for this environment. The diversity gain for selection, maximal ratio, and equal gain combining for the 10% probability level is presented as a function of power imbalance and correlation between branches for a two-branch Rayleigh diversity systemMaster of Science
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King, Timothy William. "Optimization of the Fading MIMO Broadcast Channel: Capacity and Fairness Perspectives." Thesis, University of Canterbury. Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/3201.
Full textAbstract:
Multiple input multiple output (MIMO) systems are now a proven area in
current and future telecommunications research. MIMO wireless channels, in
which both the transmitter and receiver have multiple antennas, have been
shown to provide high bandwidth efficiency. In this thesis, we cover MIMO
communications technology with a focus on cellular systems and the MIMO
broadcast channel (MIMO-BC).
Our development of techniques and analysis for the MIMO-BC starts with
a study of single user MIMO systems. One such single user technique is that of
antenna selection. In this thesis, we discuss various flavours of antenna selection, with the focus on powerful, yet straightforward, norm-based algorithms.
These algorithms are analyzed and the results of this analysis produce a powerful and flexible power scaling factor. This power scaling factor can be used
to model the gains of norm-based antenna selection via a single signal-to-noise
ratio (SNR)-based parameter. This provides a powerful tool for engineers interested in quickly seeing the effects of antenna selection on their systems. A
novel low complexity power allocation scheme follows on from the selection
algorithms. Named “Poor Man’s Waterfilling” (PMWF), this scheme can provide significant gains in low SNR systems with very little extra complexity
compared to selection alone.
We then compare a variety of algorithms for the MIMO-BC, ranging from
selection to beamforming, to the optimal, yet complex, iterative waterfilling
(ITWF) solution. In this thesis we show that certain algorithms perform better
in different scenarios, based on whether there is shadow fading or not. A power
scaling factor analysis is also performed on these systems. In the cases where
the user’s link gains are widely varying, such as when shadowing and distance
effects are present, user fairness is impaired when optimal and near optimal
throughput occurs.
This leads to a key problem in the MIMO-BC, the balance between user
fairness and throughput performance. In an attempt to find a suitable balance
between these two factors, we modify the ITWF algorithm by both introducing extra constraints and also by using a novel utility function approach. Both
these methods prove to increase user fairness with only minor loss in throughput over the optimal systems.
The introduction of MIMO systems to the cellular domain has been hampered by the effects of interference between the cells. In this thesis we move
MIMO to the cellular domain, addressing the interference using two different
methods. We first use power control, where the transmit power of the base
station is controlled to optimize the overall system throughput. This leads
to promising results using low complexity methods. Our second method is a
novel method of collaboration between base stations. This collaboration transforms neighbouring cell sectors into macro-cells and this results in substantial
increases in performance.
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Bandeira, Carlos Igor Ramos. "Interference alignment in wireless communication systems: precoding design, scheduling and channel imperfections." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/7883.
Full textAbstract:
BANDEIRA, C. I. R. Interference alignment in wireless communication systems: precoding design, scheduling and channel imperfections. 2012. 91 f. Dissertação (Mestrado em Engenharia de Teleinformática) - Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2012.Submitted by Marlene Sousa (mmarlene@ufc.br) on 2014-04-02T12:15:57Z No. of bitstreams: 1 2012_dis_cirbandeira.pdf: 1451016 bytes, checksum: e08c0d3121c26d7cb08fbfbc287c5c23 (MD5)
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In multiuser MIMO systems, the transmitter can select a subset of antennas and/or users which have good channel conditions to maximize the system throughput using various selection criteria. Furthermore, precoding can provide free interference dimensions. The Interference Alignment (IA) is based on the concept of precoding and it offers different trade-offs between complexity and performance. The basic idea of Interference Alignment consists in precoding the transmitted signals such that they are aligned at the receiver where they constitute interference, while at the same time disjointed from the desired signal. However, the Channel State Information (CSI) has been a concern because it impacts the performance of IA algorithms. Hence, we propose to analyze the performance of antenna selection and multiuser diversity together in order to allow opportunistic IA using several criteria over the disturbance of CSI. Analyses and simulations verify the behavior of the proposed scheme.
Em sistemas MIMO multiusuário, o transmissor pode selecionar um subconjunto de antenas e/ou usuários que têm bons canais para maximizar o rendimento do sistema usando vários critérios de seleção. Além disso, os pré-codificadores podem proporcionar dimensões livres de interferência. O alinhamento de interferência (IA) é baseado no conceito de pré-codificação e oferece diferentes compromissos entre complexidade e desempenho. A idéia básica do Alinhamento Interferência consiste em pré-codificar os sinais transmitidos de maneira que os mesmos sejam alinhados no receptor, em que eles constituem interferência, enquanto que ao mesmo tempo os separa do sinal desejado. No entanto, a Informação do Estado do Canal (CSI) tem sido uma preocupação para os pesquisadores porque ela tem um impacto no desempenho de algoritmos de IA. Assim, nos propomos a analisar o desempenho da seleção de antena e diversidade multiusuário em conjunto, a fim de permitir o IA oportunista usando vários critérios com relação à perturbação da CSI. Análises e simulações verificam o comportamento do esquema proposto.
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Starý, Vladimír. "Modelování antén letounu VUT 100." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218039.
Full textAbstract:
The thesis is aimed to analyze parameters of antennas, and work out the computer, which can be used to the modeling of the radiation of antennas of the VUT 100 aircraft. First, used antennas are divided according to the operation frequencies, and the polarization. Second, a MATLAB program is developed and described. The program computes radiation patterns at different frequencies for the different location of antennas on the VUT aircraft. Finally, the MATLAB optimization program is develop and described. The program changes the position of antennas so that the requirements of aircraft producer can be met.
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Gaur, Sudhanshu. "Interference management in MIMO networks." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24769.
Full textAbstract:
Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Mary Ann Ingram; Committee Member: Geoffrey Li; Committee Member: Gregory Durgin; Committee Member: Prasad Tetali; Committee Member: Raghupathy Sivakumar.
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Ya-WenHsiao and 蕭雅文. "The Antenna Design with Band Selection." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09995826887780080155.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
98
In this thesis, we proposed a planar coupling antenna design with the band selection function. The design is composed of a coupling PIFA model and a coupling open loop model. Using the simple fastening rotary switch to do the two different operating bands switch and those two kinds of models resonate at the different bands respectively; in this thesis, the proposed antenna is suitable to be applied to the laptop and mobile devices. Compared with the antennas using the electronic switch control to achieve the multi-band, there are some advantages of the proposed antenna. First, there is no extra energy loss at the components. Second, the cost of developing produces by using the simple fastening rotary switch is cheaper than the electronic switch. This design not only can operate in American’s operation GSM850 (824~896 MHz)/PCS (1850~1990 MHz), but can operate in Europe’s GSM900 (880~960 MHz)/DCS (1710~1880 MHz) systematic demand. Briefly, the antenna design which we proposed can cover the wide-band operation of the GSM850/900/1800/1900/UMTS operation. Above all, the obtained results show that the radiation efficiency of the antenna all can be more than 50% as well. Hence, these radiation efficiencies can satisfy with the requirement of industry.
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Sudarshan, Pallav. "Antenna selection and space-time spreading methods for multiple-antenna systems." 2004. http://www.lib.ncsu.edu/theses/available/etd-01042005-200617/unrestricted/etd.pdf.
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Herath, Prasanna. "Relay and antenna selection for cooperative communication." Thesis, 2012. http://handle.uws.edu.au:8081/1959.7/515061.
Full textAbstract:
This thesis investigates the effectiveness of relay selection and antenna selection for cooperative wireless communication networks. Analytical expressions are derived for the outage probability and error rates, followed by verification through computer simulation. First, two relay selection schemes are considered. A new relay selection scheme is proposed (Distributed switch-and-examine combining with threshold-based relaying; DSEC-T) and lower bounds of the outage probability and symbol error rate are derived assuming Rayleigh fading channels. Then the performance improvements that can be achieved by partial relay selection in mixed Rayleigh and Rician fading environment are investigated by deriving expressions for the outage probability and bit error rate. Both relay selection schemes considerably decrease the outage probability and error rates while reducing the system complexity. Next the performance of a dual-hop multiple antenna relay network is investigated when the relay is subject to interference. In this network, the source and the destination consist of multiple antennas while the number of antennas at the relay is limited to one. Transmit antenna selection at the source is coupled with maximal ratio combining, equal gain combining or selection combining at the destination. The outage probability of this network is investigated assuming Rayleigh fading channels. In dual-hop systems, it is shown that the impact of interference can be lowered by increasing the number of antennas at the source and the destination. Finally the performance of a fixed relay (infrastructure relay) network is analyzed. In this network, the relay consists of two receive antennas and performs switch-and-stay combining with threshold-based relaying. Lower bounds of the outage probability and symbol error rate for a range of modulation schemes are derived assuming Rayleigh fading channels. It is found that, the switch-and-stay antenna selection scheme considerably reduces the outage probability and symbol error rate while maintaining the complexity at a tractable level.
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Zhang, Hongyuan. "MIMO communications systems antenna selection and interference mitigation /." 2006. http://www.lib.ncsu.edu/theses/available/etd-07252006-140721/unrestricted/etd.pdf.
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Abou, Saleh HASSAN. "Predictive Wireless Antenna Selection for High Mobility Conditions." Thesis, 2013. http://hdl.handle.net/1974/7791.
Full textAbstract:
Accurate channel knowledge is indispensable to the practical success of channel-aware wireless communication technologies. However, channel estimates obtained from pilot symbols rapidly become outdated due to fast time variations of multipath fading channels.
To reduce system cost, antenna subset selection reduces radio frequency (RF) chain components. For systems selecting a subset of a plurality of antennas for reception, this outdated channel information is a significant impediment to selection and data decoding reliability.
In this thesis, training-based schemes for antenna selection (AS) for time-varying channels which account for practical constraints such as training, packetization and antenna switching time are proposed based on discrete prolate spheroidal sequences. They only operate with knowledge or estimates of the Doppler frequency and the channel signal-to-noise ratio (SNR), but do not require detailed statistical correlation knowledge.
A pilot-based AS scheme for time-varying frequency-flat channels for single input-multiple output (SIMO) systems
selecting one of a plurality of antennas using packet or symbol-rate antenna switching is first proposed. It is demonstrated that the presented scheme provides significant performance gain over AS methods using Fourier-based orthogonal training as well as over single antenna systems with perfect channel knowledge. Analytical expressions for the symbol error probability (SEP) of M-ary phase-shift keying (MPSK) for systems employing the suggested techniques are provided.
The second part of this thesis investigates the more general case of selecting a subset of a plurality of receive antennas. A new pilot-based receive antenna subset selection algorithm for time-varying frequency-flat channels is presented. The proposed AS algorithm is shown to outperform AS methods based on Fourier prediction/estimation as well as SIMO systems with perfect channel knowledge. Analysis of MPSK and quadrature amplitude modulation (MQAM) SEP for systems with receive AS is provided.
The combination of AS and orthogonal frequency division multiplexing (OFDM) over the more realistic time-varying and frequency-selective fading scenario is examined in the final part. Training schemes for receive AS using packet-rate antenna switching for SIMO and multiple input-multiple output (MIMO) OFDM systems are developed. The suggested schemes exhibit a superior performance over AS methods using either linear interpolation/extrapolation or Fourier prediction/estimation techniques.Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2013-01-30 16:47:06.057
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Ma, Rui-Xiang, and 馬瑞祥. "Reduced-Complexity Antenna Selection for MIMO Communication Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/29555837396494615655.
Full textAbstract:
碩士國立中正大學
通訊工程研究所
95
Multi-input multi-output (MIMO) communication systems that employ more than one antenna element at both transmitter and receiver are showed to be an efficient method to increase channel capacity. For MIMO communication systems, the major concern is the hardware complexity and computational cost. A promising solution way is to employ the antenna subset selection at the receiver and the antennas are selected to maximize channel capacity. In order to reduce capacity loss and maximize channel capacity, the thesis uses two antenna selection schemes, decremental selection algorithm (DSA) and incremental selection algorithm (ISA), which recursively drop or select one more antenna element in the pre step. However, there are high computational complexity of matrix inversion in these algorithms. In order to reduce computational complexity, the Householder transformation is utilized to alleviate the overall computational complexity of the system. Finally, simulations are conducted to compare these antenna selection algorithms in terms of computational complexity and performance.
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Kung, Chen-Hsien, and 龔振賢. "Energy-Efficiency of MIMO System with Antenna Selection." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99318494313711672511.
Full textAbstract:
碩士國立中正大學
通訊工程學系
98
In wireless communication, the average power consumption of system can be divided into two main components: the power consumption of all the power amplifiers and the power consumption of all other circuit blocks. In multiple-input multiple-output (MIMO) communication systems, the spatial diversity scheme of MIMO system can decrease the error rate of the transmitted signals effectively. In other words, achieving the same error rate communication conditions, MIMO communication systems can transmit signals with lower power than the tradition single–input single-output (SISO) communication system. However, in short-range communication environment such as sensor networks where the circuit energy consumption is comparable to or even dominates the transmission energy. The multiple radio frequency (RF) chains associated with multiple antennas in MIMO systems will increase the circuit energy consumption. And the increasing circuit energy consumption may possible decrease the energy-efficiency of transmission. In the thesis, we can apply the antenna selection technique to MIMO systems. Employing the antenna selection technique, the system can use the antenna subset which has better channel response to transmit signals. By using antenna selection technique, we can get the better energy-efficiency in wireless communication.
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Lai, Ying-Jie, and 賴英傑. "Antenna Selection Techniques in the Interfered MIMO Systems." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24061667222717133763.
Full textAbstract:
碩士國立臺灣大學
電信工程學研究所
101
Multiple-input and multiple-output (MIMO) systems can improve the channel capacity, however MIMO systems equip the multiple expensive RF chains, increasing the cost and complexity of the hardware. Therefore, antenna selection, choosing a subset of antennas for transmission, is a candidate of methods to solve it. Interference is one of the primary barrier in wireless networks. Conventional systems used orthogonal signals, either in time-domain or in frequency-domain, for solving the inter-user interference. Interference alignment is an alternative based on precoding technique, using the ideal of overlapping interference space, and a half of degrees of freedom (DoF) can be achievable per antenna per user. In this thesis, we proposes a spatial domain IA scheme and antenna selection in the three-user multiple-input multiple-output (MIMO) systems. First, a decrement method is used to choose the antenna subset, and execute interference alignment technique. Second, this decrement method is extended to the noisy channel environment. Last, a minimum mean square error (MMSE) equalizer is applied for the signal detection, and its bit error rate (BER) performance is compared with the zero-forcing decoder.
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Tsao, Wei-Wen, and 曹瑋文. "Low-Complexity Precoding and Antenna Selection of LTE System." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/26803923470686956945.
Full textAbstract:
碩士國立臺灣海洋大學
通訊與導航工程學系
102
Due to the advantages of high data rate and efficacy spectrum utilization, Multiple Input Multiple Output (MIMO) has been widely used in the broadband communication systems. However, as the number of the adopted antennas at both the transmitter and receiver is increasing, the computational complexity will be rapidly increased. To solve this problem, a promising method is to select the best set of antenna among the available ones for transmission. In LTE System, Channel State Information (CSI) can be acquired at the transmitter via three parameter, i.e., Rank Indicator (RI), Precoding Matrix Indicator (PMI) and Channel Quality Indicator (CQI). These parameters can help the transmitter to adjust the signals dynamically to have a better transmission quality. This thesis studies the RI, PMI and Antenna Selection methods and proposes several schemes to have the advantage of low computational complexity. Keyword: Multiple Input Multiple Output system; antenna selection; LTE; Rank Indicator (RI); Precoding Matrix Indicator (PMI);
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Li-Chang-Mu and 李昌穆. "Study of Space Time Coding with Receive Antenna Selection." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/86241650067664310671.
Full textAbstract:
碩士國立暨南國際大學
通訊工程研究所
97
There can be two space-time codes for MIMO systems: space-time block code (STBC) and space-time trellis code (STTC). And it was reported that receive antenna selection (RAS) can provide the competent performance and can reduce the computational complexity. In this thesis, we study STBC, STTC, and their combination: STTC-STBC. To evaluate the effects of RAS on space-time coding, we further impose RAS on STBC, STTC, and STTC-STBC. Simulation results show that the bit error rate (BER) for the schemes with RAS is close to that for the schemes without RAS, and STTC-STBC has the lowest BER among all studied schemes. Also, we evaluate the computational complexity for the studied schemes and the results show the schemes with RAS can have lower computational complexity than the schemes without RAS.
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Hung, Chia Hung, and 洪嘉鴻. "Transmit Antenna Selection for 802.11ac Uplink MU-MIMO Systems." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/74029611074828941077.
Full textAbstract:
碩士國立清華大學
資訊工程學系
104
Multiple-input and multiple-output (MIMO) is a technique that achieves significant communication performance by allowing multiple antennas to simultaneously communicate. However, the achievable throughput highly depends on the channel state of the antennas which are transmitting concurrently. The target of this thesis is to improve the system throughput in interference-cancellation-based MU-MIMO by our proposed transmit antenna selection strategy. The whole proposed scheme consists of two procedures—antenna extraction procedure (based on the anisotropic orthogonal Procrustes analysis) and antenna ordering procedure. Simulation results indicate that our proposed scheme improves system throughput and that the performance of our proposed strategy is excellent in comparison with other schemes.
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Huang, Kuei-Jung, and 黃奎彰. "Precoding Matrix and Antenna Selection of LTE-Advanced System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/19805661972669800456.
Full textAbstract:
碩士國立臺灣海洋大學
通訊與導航工程學系
104
LTE-Advanced is developed by 3rd Generation Partnership Project (3GPP) to meet the requirements for 4G System of International Telecommunication Union (IUT).With wider bandwidth utilization, spectral improvement and the MIMO adoption , the throughput of the 4G system can be greatly increased. LTE-Advanced defines eight transmit antennas in downlink, and dual codebooks are adopted. According to current channel state, precoding matrix indicator of channel state information will be returned to inform the transmitter to adjust signal transmission. However, as the numbers of antenna increase, system hardware and the computation complexity will also be increased in a MIMO system. In this thesis, several novel methods are proposed to select the dual codebooks for LTE-A System. Besides, low complexity antenna selection techniques are also provided to have the low complexity advantage and still maintain the good BER and capacity performances. It can reduce the 55 percent and 75 percent computation complexity and have the same performance compared with conventional methods.
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Chen, Wei-Liang, and 陳威良. "Study of Antenna-Selection Algorithms for MIMO-OFDM Systems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/93517490998557723846.
Full textAbstract:
碩士國立暨南國際大學
通訊工程研究所
99
In the thesis, we study of antenna-selection algorithm based on constrained adaptive Markov chain Monte Carlo(CAMCMC) optimization method with different antenna selection criteria in multiple-input multiple-output-orthogonal frequency division multiplexing(MIMO-OFDM).Show that both the channel capacity and the system BER by the CAMCMC algorithm are close to the exhaustive search(ES). We further demonstrate that the complexity of CAMCMC can be achieved with less than 10% of the complexity of ES rule. Simulate the different antenna-selection algorithm, and change the selected antennas…We find the performance of the CAMCMC algorithm are close to the ES, though the performance can’t be the same, but CAMCMC reduce a lot of computational complexity compare with ES.
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Huang, Shin-Hua, and 黃信華. "Multimode Switching and Antenna Selection Techniques for MIMO Systems." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/97723646495503223580.
Full text
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Lin, Chia-Hung, and 林家宏. "Study on MIMO Antenna Selection Based on Deep Learning." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/hv2hj8.
Full textAbstract:
碩士國立中山大學
通訊工程研究所
106
MIMO technology can improve the spectral efficiency of the communication system obviously. And we usually employ antenna selection technology when we implement MIMO on the mobile device. The benefit of antenna selection are that we can make the most of the advantage of MIMO technology and lower the total power of the transmitter. But most of the antenna selection technology are too complex to be implemented on the mobile device. Industry are forced to use the Maximum norm method which is based on the concept of choosing the single antenna. In this paper, we purpose the finite state machine antenna selection method. This method can solve any antenna selection problem with fix antenna setting. In the over the air test, the purpose method can surpass the Maximum norm method in terms of performance under affordable computing complexity. And the performance of this method will not drop immediately which is common in Maximum norm method. We also purpose the antenna selection network based on deep learning. Instead of the traditional method like increasing the number of the training samples or using some mathematical methods, we employ the random channel shifter to solve the overfitting problem in the training process perfectly. Finally, we use the antenna selection with the ensemble learning to enhance the ability of the antenna selection network. In various testing environment, this method can achieve the performance close to brute force method when the complexity is only many times of random selection.
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Ahmadi, Shokouh Javad. "Receive Soft Antenna Selection for Noise-Limited/Interference MIMO Channels." Thesis, 2008. http://hdl.handle.net/10012/4085.
Full textAbstract:
Although the Multi-Input and Multi-Output (MIMO) communication systems provide
very high data rates with low error probabilities, these advantages are obtained
at the expense of having high signal processing tasks and the hardware cost,
e.g. expensive Analog-to-Digital (A/D) converters. The increased hardware cost
is mainly due to having multiple Radio Frequency (RF) chains (one for each antenna
element). Antenna selection techniques have been proposed to lower the
number of RF chains and provide a low cost MIMO system. Among them, due to a
beamforming capability Soft Antenna Selection (SAS) schemes have shown a great
performance improvement against the traditional antenna sub-set selection methods
for the MIMO communication systems with the same number of RF chains.
A SAS method is basically realized by a pre-processing module which is located
in RF domain of a MIMO system. In this thesis, we investigate on the receive
SAS-MIMO, i.e. a MIMO system equipped with a SAS module at the receiver side,
in noise-limited/interference channels. For a noise-limited channel, we study the
SAS-MIMO system for when the SAS module is implemented before Low Noise
Amplifier (LNA), so-called pre-LNA, under both spatial multiplexing and diversity
transmission strategies. The pre-LNA SAS module only consists of passive
elements. The optimality of the pre-LNA SAS method is investigated under two
di erent practical cases of either the external or internal noise dominates. For the
interference channel case, the post-LNA SAS scheme is optimized based on Power
Angular Spectrum (PAS) of the received interference signals. The analytical derivations
for both noise-limited and interference channels are verified via the computer
simulations based on a general Rician statistical MIMO channel model. The simulation
results reveal a superiority of the post-LNA SAS to the post-LNA SAS at any
condition. Moreover, using the simulations performed for the interference channels
we show that the post-LNA SAS is upper bounded by the full-complexity MIMO.
Since in both above-mentioned channels, noise-limited and interference, the
channel knowledge is needed for the SAS optimization, in this thesis we also propose
a two-step channel estimation method for the SAS-MIMO. This channel estimation
is based on an Orthogonal Frequency-Division Multiplexing (OFDM) MIMO system.
Two di erent estimators of Least-Square (LS) and Minimum-Mean-Square-
Error (MMSE) are applied. Simulation results show a superiority of the MMSE
method to the LS estimator for a MIMO system simulated under the 802.16 framing
strategy. Moreover, a 802.11a framing based SAS-MIMO is simulated using
MATLAB SIMULINK to verify the two-step estimation procedure.
Furthermore, we also employ a ray-tracing channel simulation to assess di erent
SAS configurations, i.e. realized by active (post-LNA) and/or passive (pre-LNA)
phased array, in terms of signal coverage. In this regard, a rigorous Signal to Noise
Ratio (SNR) analysis is performed for each of these SAS realizations. The results
show that although the SAS method performance is generally said to be upperbounded
by a full-complexity MIMO, it shows a better signal coverage than the
full-complexity MIMO.
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Wong, Alex H. C. "Antenna Selection and Deployment Strategies for Indoor Wireless Communication Systems." 2007. http://hdl.handle.net/2292/432.
Full textAbstract:
Effective antenna selection and deployment strategies are important for reducing co-channel interference in indoor wireless systems. Low-cost solutions are essential, and strategies that utilise simple antennas (such as directional patches) are advantageous from this perspective. However, performance is always an issue and the improvements achievable through clever antenna deployment need to be quantified. In this thesis, an experimental investigation of indoor propagation comparing the performance of directional antennas and multiple-element arrays (MEAs) with omni-directional antennas is reported. Estimation of the performance of a direct sequence code division multiple access (DS-CDMA) system operating in a variety of deployment scenarios allows the identification of a range of performance-limiting factors and the optimal deployment strategies. It is shown that the orientation of single-element directional antennas can significantly impact on system performance compared to omni-directional antennas in traditional systems. The deployment of MEAs with an active diversity combining scheme can further improve system performance by more than one order of magnitude. From the perspective of system planning, the choice of antenna selection and deployment options depends on the current and future demand for system performance and the financial resources available. An evolutionary path has been proposed to provide a smooth transition from conventional (low-cost) to high-performance (high-cost) antenna systems as demand dictates. Other performance-limiting factors in indoor wireless systems include the physical environment and external interference. It is also shown that electromagnetically-opaque obstacles in the environment can amplify the effectiveness of the antenna deployment by acting as physical zone boundaries that restrict interference. External interference has been shown to cause a significant degradation to the performance of an indoor system when the carrier-to-external-interference ratio (CEIR) is below 30 dB. This performance degradation can be minimised by appropriate antenna deployment, although the optimum antenna orientations depends on the strength of the external interference.
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Abou, Saleh Hassan A. "Antenna selection and performance analysis of MIMO spatial multiplexing systems." Thesis, 2008. http://spectrum.library.concordia.ca/976171/1/MR45270.pdf.
Full textAbstract:
Multiple-input multiple-output spatial multiplexing (MIMO-SM) systems offer an essential benefit referred to as spatial multiplexing gain. Two important signal reception techniques for MIMO-SM systems are the zero-forcing (ZF) and ordered successive interference cancellation (OSIC) as, for example, in the case of the decision-feedback detector (DFD). This thesis studies the communication and signal processing aspects of MIMO-SM. We first investigate the bit error rate (BER) performance of the ZF receiver over transmit correlated Ricean flat-fading channels. In particular, for a MIMO channel with M transmit and N receive antennas, we derive an approximation for the average BER of each sub-stream. A closed-form expression for the optimal transmit correlation coefficient, which achieves the maximum capacity (i.e., uncorrelated case) of two-input two-output spatial multiplexing (TITO-SM) systems, is presented. We further propose an antenna selection (AS) approach for the DFD over independent Rayleigh flat-fading channels. The selected transmit antennas are those that maximize both the post-processing signal-to-noise ratio (SNR) at the receiver end, and the system capacity. An upper bound on the outage probability for the AS approach is derived. It is shown that the AS approach achieves a performance comparable to optimal capacity-based selection based on exhaustive search, but at a lower complexity. Finally, we investigate a cross-layer transmit AS approach for the DFD over spatially correlated Ricean flat-fading channels. The selected transmit antennas are those that maximize the link layer throughput of correlated MIMO channels. A closed-form expression for the system throughput with perfect channel estimation is first derived. We further analyze the system performance with pilot-aided channel estimation. In that, we derive a closed-form expression for the post-detection signal-to-noise-plus-interference ratio (SNIR) of each transmitted substream, conditioned on the estimated channels. The derived SNIR is then used to evaluate the overall system throughput. It is observed that the cross-layer AS approach always assigns the transmission to the antenna combination which sees better channel conditions, resulting in a substantial improvement over the optimal capacity-based AS approach. Considering a training-based channel estimation technique, we compare the performance of the proposed cross-layer AS with that of optimal capacity-based AS when employed with a training-based channel estimation. Our results show that the latter is more robust to imperfect channel estimation. However, in all cases, the cross-layer AS delivers higher throughput gains than the capacity-based AS
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Te-Hung, Wang, and 王德弘. "Combination of Antenna Selection and Power Allocation for MC-CDMA." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/36831244591976388216.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
93
In this thesis, we present a combined scheme of power allocation and antenna selection to improve the bit error rate (BER) performance for multiple input multiple output (MIMO) multicarrier code division multiple access (MC-CDMA) systems over frequency selective Rayleigh fading channels. MIMO configurations with space-time block code (STBC) technology can enhance system performance by improving the spatial diversity order, while MC-CDMA systems provide frequency diversity and multiple access capability by frequency domain spreading and multicarrier modulation. The proposed scheme combines the advantages of these technologies by appropriately selecting the transmit antennas with higher channel gain and allocating the limited transmission power resources among them to improve the overall system performance. The scheme we proposed is to first select the best transmit antenna with highest channel Frobenius norm for each subcarrier. Then, the transmission power is allocated among these subcarriers by water-filling (WF) algorithm to improve the overall system performance. The antennas selection is performed in spatial diversity dimension on each subcarrier employing the norm-based criterion, with the power being allocated in frequency diversity domain to maximize the channel capacity across the subcarriers. The power allocation among the subcarriers is a constrained optimization problem that can be solved by using the Lagrange multiplier method. Simulation results show that the new scheme can provide considerable performance gain.
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Yeh, Wan-Chen, and 葉宛真. "Multimode Antenna Selection with Reduced Complexity for Zero-forcing Receiver." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/3c2brd.
Full textAbstract:
碩士國立交通大學
電控工程研究所
98
In this thesis, we proposed reduced-complexity algorithms to select appropriate transmit antennas for MIMO system with zero-forcing receiver. Two criteria for selecting antennas are derived: achievable data rate maximization and average symbol error rate minimization. In addition, bit allocation is also applied to improve the performance. The computational complexity can be reduced by simplifying search strategy and matrix inversion. The computational complexity analysis and simulation results are given to see that the advantages of the proposed algorithm.