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1
Shekhar, Hemabh. "Multi-antenna physical layer models for wireless network design". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22681.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Ingram, Mary Ann; Committee Member: Andrew, Alfred; Committee Member: Copeland, John; Committee Member: Owen, Henry; Committee Member: Sivakumar, Raghupathy.
2
Jiang, Meilong. "Robust cross-layer scheduling design in multi-user multi-antenna wireless systems". Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38346758.
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Jiang, Meilong, i 江美龍. "Robust cross-layer scheduling design in multi-user multi-antenna wireless systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38346758.
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Pollock, Tony Steven. "On limits of multi-antenna wireless communications in spatially selective channels /". View thesis entry in Australian Digital Theses Program, 2003. http://thesis.anu.edu.au/public/adt-ANU20050418.143712/index.html.
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Yanikömeroglu, Halim. "Multi-antenna systems and interconnection strategies for CDMA wireless access networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/NQ41536.pdf.
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Elsabae, Ramadan G. M. "Optimization techniques for reliable data communication in multi-antenna wireless systems". Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/34613.
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This thesis looks at new methods of achieving reliable data communication in wireless communication systems using different antenna transmission optimization methods. In particular, the problems of exploitation of MIMO communication channel diversity, secure downlink beamforming techniques, adaptive beamforming techniques, resource allocation methods, simultaneous power and information transfer and energy harvesting within the context of multi-antenna wireless systems are addressed.
7
Pollock, Tony Steven, i tony pollock@nicta com au. "On Limits of Multi-Antenna Wireless Communications in Spatially Selective Channels". The Australian National University. Research School of Information Sciences and Engineering, 2003. http://thesis.anu.edu.au./public/adt-ANU20050418.143712.
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Multiple-Input Multiple-Output (MIMO) communications systems using multiantenna arrays simultaneously during transmission and reception have generated significant interest in recent years. Theoretical work in the mid 1990?s showed the potential for significant capacity increases in wireless channels via spatial multiplexing with sparse antenna arrays and rich scattering environments. However, in reality the capacity is significantly reduced when the antennas are placed close together, or the scattering environment is sparse, causing the signals received by different antennas to become correlated, corresponding to a reduction of the effective number of sub-channels between transmit and receive antennas. By introducing the previously ignored spatial aspects, namely the antenna array geometry and the scattering environment, into a novel channel model new bounds and fundamental limitations to MIMO capacity are derived for spatially constrained, or spatially selective, channels. A theoretically derived capacity saturation point is shown to exist for spatially selective MIMO channels, at which there is no capacity growth with increasing numbers of antennas. Furthermore, it is shown that this saturation point is dependent on the shape, size and orientation of the spatial volumes containing the antenna arrays along with the properties of the scattering environment. This result leads to the definition of an intrinsic capacity between separate spatial volumes in a continuous scattering environment, which is an upper limit to communication between the volumes that can not be increased with increasing numbers of antennas within. It is shown that there exists a fundamental limit to the information theoretic capacity between two continuous volumes in space, where using antenna arrays is simply one choice of implementation of a more general spatial signal processing underlying all wireless communication systems.
8
Zhou, Xiangyun. "Transmission resource allocation in multi-antenna wireless communication systems with channel uncertainty". Phd thesis, Institute of Electrical and Electronics Engineers (IEEE), 2013. http://hdl.handle.net/1885/9828.
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In this thesis we investigate the design of transmission resource allocation in current and future wireless communication systems. We focus on systems with multiple antennas and characterize their performance from an information-theoretic viewpoint. The goal of this work is to provide practical transmission and resource allocation strategies taking into account imperfections in estimating the wireless channel, as well as the broadcast nature of the wireless channel. In the first part of the thesis, we consider training-based transmission schemes in which pilot symbols are inserted into data blocks to facilitate channel estimation. We consider one-way training-based systems with and without feedback, as well as two-way training-based systems. Two-way training enables both the transmitter and the receiver to obtain the channel state information (CSI) through reverse training and forward training, respectively. In all considered cases, we derive efficient strategies for transmit time and/or energy allocation among the pilot and data symbols. These strategies usually have analytical closed-form expressions and can achieve near optimal capacity performance evidenced by extensive numerical analysis.
In one-way training-based systems without feedback, we consider both spatially independent and correlated channels. For spatially independent channels, we provide analytical bounds on the optimal training length and study the optimal antenna con¯guration that maximizes an ergodic capacity lower bound. For spatially correlated channels, we provide simple pilot and data transmission strategies that are robust under least-favorable channel correlation conditions. In one-way training-based systems with feedback, we study channel gain feedback (CGF), channel covariance feedback (CCF) and hybrid feedback. For spatially independent channels with CGF, we show that the solutions to the optimal training length and energy coincide with those for systems without feedback. For spatially correlated channels with CCF, we propose a simple transmission scheme, taking into account the fact that the optimal training length is at most as large as the number of transmit antennas. We then provided solution to the optimal energy allocation between pilot and data transmissions, which does not depend on the channel spatial correlation under a mild condition. Our derived resource allocation strategies in CGF and CCF systems are extended to hybrid CCF-CGF systems.
In two-way training-based systems, we provide analytical solutions to the transmit power distribution among the different training phases and the data transmission phase. These solutions are shown to have near optimal symbol error rate (SER) and capacity performance. We find that the use of two-way training can provide noticeable performance improvement over reverse training only when the system is operating at moderate to high signal-to-noise ratio (SNR) and using high-order modulations. While this improvement from two-way training is insignificant at low SNR or low-order modulations. In the second part of the thesis, we consider transmission resource allocation in security-constrained systems. Due to the broadcast nature of the wireless medium, security is a fundamental issue in wireless communications. To guarantee secure communication in the presence of eavesdroppers, we consider a multi-antenna transmission strategy which sends both an information signal to the intended receiver and a noise-like signal isotropically to confuse the eavesdroppers. We study the optimal transmit power allocation between the information signal and the artificial noise. In particular, we show that equal power allocation is a near optimal strategy for non-colluding eavesdroppers, while more power should be used to generate the artificial noise for colluding eavesdroppers. In the presence of channel estimation errors, we find that it is better to create more artificial noise than to increase the information signal strength.
9
Sellathurai, Mathini. "Turbo-blast : a novel technique for multi-transmit and multi-receive wireless communications /". *McMaster only, 2001.
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Yeh, Ho-Hsin. "Developments of 60 GHz Antenna and Wireless Interconnect inside Multi-Chip Module for Parallel Processor System". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/272872.
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In order to carry out the complicated computation inside the high performance computing (HPC) systems, tens to hundreds of parallel processor chips and physical wires are required to be integrated inside the multi-chip package module (MCM). The physical wires considered as the electrical interconnects between the processor chips, however, have the challenges on placements and routings because of the unequal progress between the semiconductor and I/O size reductions. The primary goal of the research is to overcome package design challenges - providing a hybrid computing architecture with implemented 60 GHz antennas as the high efficient wireless interconnect which could generate over 10 Gbps bandwidth on the data transmissions. The dissertation is divided into three major parts. In the first part, two different performance metrics, power loss required to be recovered (PRE) and wireless link budget, on evaluating the antenna's system performance within the chip to chip wireless interconnect are introduced to address the design challenges and define the design goals. The second part contains the design concept, fabrication procedure and measurements of implemented 60 GHz broadband antenna in the application of multi-chip data transmissions. The developed antenna utilizes the periodically-patched artificial magnetic conductor (AMC) structure associated with the ground-shielded conductor in order to enhance the antenna's impedance matching bandwidth. The validation presents that over 10 GHz -10 dB S11 bandwidth which indicates the antenna's operating bandwidth and the horizontal data transmission capability which is required by planar type chip to chip interconnect can be achieved with the design concept. In order to reduce both PRE and wireless link budget numbers, a 60 GHz two-element array in the multi-chip communication is developed in the third part. The third section includes the combined-field analysis, the design concepts on two-element array and feeding circuitry. The simulation results agree with the predicted field analysis and demonstrate the 5dBi gain enhancement in the horizontal direction over a single 60 GHz AMC antenna to further reduce both PRE and wireless link budget numbers.
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Kassouf, Marthe. "Capacity and information rates for multiple antenna wireless systems with multi-dimensional modulation". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97781.
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Multiple-Input Multiple-Output (MIMO) systems have shown a great potential for increasing the data transmission rates in wireless communications. These systems are characterized by a high design flexibility which allows a wide variety of efficient signaling techniques and resource allocation methods. In this thesis, we consider the capacity and transmission rates for MIMO systems using various multi-dimensional space-time modulation formats. The latters refer to various allocations of orthogonal signal dimensions (or modulating waveforms) to transmit antennas. For a single-user system with a fixed transmit power, we investigate the most efficient allocations of power and signal dimensions to transmit antennas so that transmission rates can be maximized under different cases of channel state information at the transmitter (CSIT). In many situations, we show that using all the signal dimensions on all the transmit antennas yields the largest rates. An analysis of the capacity and transmission rates is also provided at low and high SNR, where the effect of the spatial channel parameters is pointed out. For a broadcast system, we consider the power and signal dimensions allocations not only for transmit antennas, but also among users. [...]Les systemes a entree multiple et sortie multiple permettent d’augmenter le debit de transmission de donnees dans les reseaux de communication sans fil. Ces systemes sont caracterises par une grande flexibilite de conception, ce qui leur permet d’accommoder une grande variete de techniques de signalisation et d’attribution de ressources. Dans cette these, nous considerons la capacite et les debits de transmission possibles pour les systemes a entree multiple et sortie multiple utilisant une variete de formats de modulation espacetemps multidimensionnelle. Ces formats correspondent a differentes manieres d’ attribuer les dimensions orthogonales du signal aux antennes de transmission. Pour un systeme ayant un seul usager et moyennant une puissance de transmission fixe, nous examinons comment attribuer la puissance et les dimensions du signal aux antennes de transmission, de maniere a maximiser les debits de transmission en tenant compte de 1’information sur l’etat du canal dont dispose le transmetteur. Dans plusieurs situations, nous demontrons qu’utiliser toutes les dimensions du signal sur chaque antenne de transmission permet d’atteindre de plus hauts debits de transmission. [...]
12
Nagy, Amr. "Performance enhancement for filter bank multicarrier methods in multi-antenna wireless communication systems". Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30532.
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This thesis investigates filter bank based multicarrier modulation using offset quadrature amplitude modulation (FBMC/OQAM), which is characterised by a critically sampled FBMC system that achieves full spectral efficiency in the sense of being free of redundancy. As a starting point, a performance comparison between FBMC/OQAM and oversampled (OS) FBMC systems is made in terms of per-subband fractionally spaced equalisation in order to compensate for the transmission distortions caused by dispersive channels. Simulation results show the reduced performance in equalising FBMC/OQAM compared to OS-FBMC,where the advantage for the latter stems from the use of guard bands. Alternatively, the inferior performance of FBMC/OQAM can be assigned to the inability of a per-subband equaliser to address the problem of potential intercarrier interference(ICI) in this system. The FBMC/OQAM system is analysed by representing the equivalent transmultiplexed channel including the filter banks as a polynomial matrix. The formulated polynomial matrix is demonstrated as a tri-diagonal matrix plus two corner elements which indicates that the induced ICI is limited to the direct adjacent spectrally overlapped subchannels. Based on polynomial matrix algebra, an equaliser is proposed which considers the cross terms between subchannels rather than performing a per-subband equalisation. The proposed equaliser is obtained through the inversion of the channel polynomial matrix; due to its reduced-rank nature, this inversion requires the extension of pseudo-inversion principles to the domain of polynomial matrices, and the inclusion of a regularisation term for enhanced stability and system performance. Some numerical examples demonstrate the ability of the proposed equaliser to suppress both ISI and ICI. Furthermore, this thesis combines FBMC/OQAM with multi-antenna architectures. In this scenario, the FBMC/OQAM system will not only suffer from ISI and ICI but also from spatial or inter-antenna interference (IAI). The multiple input multiple-output (MIMO) channel including the filter bank system is formulated as a polynomial matrix. A polynomial matrix pseudo-inverse of the equivalent channel polynomial matrix is proposed to approximately eliminate ISI, ICI, and IAI. Examples and simulation results are presented to underpin the performance of the proposed architecture.
13
Zhou, Lin. "Energy efficient transmitter design with compact antenna for future wireless communication systems". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33104.
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This thesis explores a novel technique for transceiver design in future wireless systems, which is cloud radio access networks (CRANs) with single radio frequency (RF) chain antennas at each remote radio head (RRH). This thesis seeks to make three contributions. Firstly, it proposes a novel algorithm to solve the oscillatory/unstable behaviour of electronically steerable parasitic array radiators (ESPAR) when it provides multi-antenna functionality with a single RF chain. This thesis formulates an optimization problem and derives closed-form expressions when calculating the configuration of an ESPAR antenna (EA) for arbitrary signals transmission. This results in simplified processing at the transmitter. The results illustrate that the EA transmitter, when utilizing novel closed-form expressions, shows significant improvement over the performance of the EA transmitter without any pre-processing. It performs at nearly the same symbol error rate (SER) as standard multiple antenna systems. Secondly, this thesis illustrates how a practical peak power constraint can be put into an EA transceiver design. In an EA, all the antenna elements are fed centrally by a single power amplifier. This makes it more probable that during use, the power amplifier reaches maximum power during transmission. Considering limited power availability, this thesis proposes a new algorithm to achieve stable signal transmission. Thirdly, this thesis shows that an energy efficiency (EE) optimization problem can be formulated and solved in CRANs that deploy single RF chain antennas at RRHs. The closed-form expressions of the precoder and power allocation schemes to transmit desired signals are obtained to maximise EE for both single-user and multi-user systems. The results show that the CRANs with single RF chain antennas provide superior EE performance compared to the standard multiple antenna based systems.
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Normando, Paulo Garcia. "Alinhamento de interferÃncia espacial em cenÃrios realistas". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10874.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorDevido ao rÃpido crescimento e os agressivos requisitos de vazÃo nas atuais redes sem fio, como os sistemas celulares de 4 a GeraÃÃo, a interferÃncia se tornou um problema que nÃo pode mais ser negligenciado. Neste contexto, o Alinhamento de InterferÃncia (IA) tem surgido como uma tÃcnica promissora que possibilita transmissÃes livres de interferÃncia com elevada eficiÃncia espectral. No entanto, trabalhos recentes tÃm focado principalmente nos ganhos teÃricos que esta tÃcnica pode prover, enquanto esta dissertaÃÃo visa dar um passo na direÃÃo de esclarecer alguns dos problemas prÃticos de implementaÃÃo da tÃcnica em redes celulares, bem como comparÃ-la com outras tÃcnicas bem estabelecidas. Uma rede composta por trÃs cÃlulas foi escolhida como cenÃrio inicial de avaliaÃÃo, para o qual diversos fatores realistas foram considerados de modo a realizar diferentes anÃlises. A primeira anÃlise foi baseada em imperfeiÃÃes de canal, cujos resultados mostraram que o IA à mais robusto aos erros de estimaÃÃo de canal que o BD (do inglÃs, Block Diagonalization), enquanto as duas abordagens sÃo igualmente afetadas pela correlaÃÃo entre as antenas. O impacto de uma interferÃncia externa nÃo-coordenada, que foi modelada por diferentes matrizes de covariÃncia de modo a emular vÃrios cenÃrios, tambÃm foi avaliado. Os resultados mostraram que as modificaÃÃes feitas nos algoritmos de IA podem melhorar bastante seus desempenho, com uma vantagem para o algoritmo que suprime um Ãnico fluxo de dados, quando sÃo comparadas as taxas de erro de bit alcanÃadas por cada um. Para combinar os fatores das anÃlises anteriores, as variaÃÃes temporais de canal foram consideradas. Neste conjunto de simulaÃÃes, alÃm da presenÃa da interferÃncia externa, os prÃ-codificadores sÃo calculados atravÃs de medidas atrasadas de canal, levando a resultados que corroboraram com as anÃlises anteriores. Um fato recorrente percebido em todas as anÃlises anteriores à o dilema entre aplicar os algoritmos baseados em BD, para que se consiga alcanÃar maiores capacidades, ou enviar a informaÃÃo atravÃs de um enlace mais confiÃvel utilizando o IA. Uma maneira de esclarecer este dilema à efetivamente realizar simulaÃÃes a nÃvel sistÃmico, para isto foi aplicado um simulador sistÃmico composto por um grande nÃmero de setores. Como resultado, todas as anÃlises realizadas neste simulador mostraram que a tÃcnica de IA atinge desempenhos intermediÃrios entre a nÃo cooperaÃÃo e os algoritmos baseados na prÃ-codificaÃÃo conjunta. Uma das principais contribuiÃÃes deste trabalho foi mostrar alguns cenÃrios em que a tÃcnica do IA pode ser aplicada. Por exemplo, quando as estimaÃÃes dos canais nÃo sÃo tÃo confiÃveis à melhor aplicar o IA do que os esquemas baseados no processamento conjunto. TambÃm mostrou-se que as modificaÃÃes nos algoritmos de IA, que levam em consideraÃÃo a interferÃncia externa, podem melhorar consideravelmente o desempenho dos algoritmos. Finalmente, o IA se mostrou uma tÃcnica adequada para ser aplicada em cenÃrios em que a interferÃncia à alta e nÃo à possÃvel ter um alto grau de cooperaÃÃo entre os setores vizinhos.
Due to the rapid growth and the aggressive throughput requirements of current wireless networks, such as the 4th Generation (4G) cellular systems, the interference has become an issue that cannot be neglected anymore. In this context, the Interference Alignment (IA) arises as a promising technique that enables transmissions free of interference with high-spectral efficiency. However, while recent works have focused mainly on the theoretical gains that the technique could provide, this dissertation aims to go a step further and clarify some of the practical issues on the implementation of this technique in a cellular network, as well as compare it to other well-established techniques. As an initial evaluation scenario, a 3-cell network was considered, for which several realistic factors were taken into account in order to perform different analyses. The first analysis was based on channel imperfections, for which the results showed that IA is more robust than Block Diagonalization (BD) regarding the Channel State Information (CSI) errors, but both are similarly affected by the correlation among transmit antennas. The impact of uncoordinated interference was also evaluated, by modeling this interference with different covariance matrices in order to mimic several scenarios. The results showed that modifications on the IA algorithms can boost their performance, with an advantage to the approach that suppresses one stream, when the Bit Error Rate (BER) is compared. To combine both factors, the temporal channel variations were taken into account. At these set of simulations, besides the presence of an external interference, the precoders were calculated using a delayed CSI, leading to results that corroborate with the previous analyses. A recurring fact on the herein considered analyses was the dilemma of weather to apply the Joint Processing (JP)-based algorithms in order to achieve higher sum capacities or to send the information through a more reliable link by using IA. A reasonable step towards solving this dilemma is to actually perform the packet transmissions, which was accomplished by employing a system-level simulator composed by a large number of Transmission Points (TPs). As a result, all analyses conducted with this simulator showed that the IA technique can provide an intermediate performance between the non-cooperation and the full cooperation scheme. Concluding, one of the main contributions of this work has been to show some scenarios/cases where the IA technique can be applied. For instance, when the CSI is not reliable it can be better to use IA than a JP-based scheme. Also, the modifications on the algorithms to take into account the external interference can boost their performance. Finally, the IA technique finds itself in-between the conventional transmissions and Coordinated Multi-Point (CoMP). IA achieves an intermediate performance, while requiring a certain degree of cooperation among the neighboring sectors, but demanding less infrastructure than the JP-based schemes.
15
Gezer, Berat Levent. "Multi-beam digital antenna for radar, communications, and UAV tracking based on off-the-shelf wireless technologies". Thesis, Monterey California. Naval Postgraduate School, 2006. http://hdl.handle.net/10945/2583.
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The state-of-art technologies keep generating new ways of improving on the performance of the old systems. Array antennas, one of the continuously improving technologies, brought many benefits to our life. The superiorities of array antennas remove the disadvantages of the old technology radars such as great sidelobes, vulnerability to the jammers, and degradation effect of the clutter. Array antennas find many applications on different areas. Today, unmanned aerial vehicles (UAVs) have begun to be seen in our life more often than before. UAVs prevent pilot loss of life. They carry out a variety of military and civilian missions such as surveillance and reconnaissance, target recognition, battle damage assessment, EW, search and rescue, and traffic monitoring. An important use of the UAVs is troop support, carrying out reconnaissance and surveillance missions, which requires maintaining a data-link with troops in order to send any data collected, such as video images, or audio. During operations it is necessary to continuously maintain a data and control link with the operator. This requires the ground station antenna to track the UAV so the antenna beam is pointed properly. The purpose of this research is to design and build an array to angle-track a UAV and, eventually, to accomplish the data transfer from the UAV to the ground station.
16
Fahmy, Nader S. Todd Terence D. "Ad hoc networks with power-controlled multi-antenna systems: MAC protocols and multihop relaying applications". *McMaster only, 2005.
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Cha, Jeongwon. "A CMOS radio-frequency front-end for multi-standard wireless communications". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37250.
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The explosive growth of wireless communication market has led the development of low-cost, highly-integrated wireless communication systems. Even though most blocks in the front-end have successfully been integrated by using the CMOS technology, it is still a formidable challenge to integrate the entire front-end. Thus, the objective of this research is to demonstrate the feasibility of the integrated front-end by using improved circuit techniques as well as the improved process technologies. This dissertation proposes an improved control scheme to enhance the high-power handling capability of an antenna switch.
As a part of this research, an antenna switch controller for a GaAs antenna switch was first developed to enhance the performances of the GaAs antenna switch by using the boosted control voltage. To enhance the efficiency of the front-end, efficiency improvement techniques for the antenna switch controller has also been studied. With the suggested efficiency improvement techniques, a fully-integrated antenna switch was implemented using the SOI technology, and exceeding performances over many commercial products for watt-level high-power applications have been successfully demonstrated. As an effort to improve the efficiency of a power amplifier, a linear envelope detector was also implemented, and the results show that the envelope detector is suitable for dynamic biasing of the power amplifier. The research presented in this dissertation, thus, provides a low-cost and high-performance solution for highly-integrated RF front-end used in various wireless communication systems.
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German, Gus R. "A ray-based investigation of the statistical characteristics and efficient representation of multi-antenna communication channels /". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd491.pdf.
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Spencer, Quentin H. "Transmission Strategies for Wireless Multi-user, Multiple-Input, Multiple-Output Communication Channels". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd378.pdf.
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Dimitrov, Emil [Verfasser]. "System design and validation of multi-band OFDM wireless communications with multiple antennas / Emil Dimitrov". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/1036694151/34.
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Liu, Lingjia. "On delay-sensitive communication over wireless systems". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2725.
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Salah, Adham M. S. "Investigation of Integrated Decoupling Methods for MIMO Antenna Systems. Design, Modelling and Implementation of MIMO Antenna Systems for Different Spectrum Applications with High Port-to-Port Isolation Using Different Decoupling Techniques". Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18427.
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Multiple-Input-Multiple-Output (MIMO) antenna technology refers to an antenna with
multiple radiators at both transmitter and receiver ends. It is designed to increase the data rate in
wireless communication systems by achieving multiple channels occupying the same bandwidth
in a multipath environment. The main drawback associated with this technology is the coupling
between the radiating elements. A MIMO antenna system merely acts as an antenna array if the
coupling between the radiating elements is high. For this reason, strong decoupling between the
radiating elements should be achieved, in order to utilize the benefits of MIMO technology.
The main objectives of this thesis are to investigate and implement several printed MIMO
antenna geometries with integrated decoupling approaches for WLAN, WiMAX, and 5G
applications. The characteristics of MIMO antenna performance have been reported in terms of
scattering parameters, envelope correlation coefficient (ECC), total active reflection coefficient
(TARC), channel capacity loss (CCL), diversity gain (DG), antenna efficiency, antenna peak gain
and antenna radiation patterns.
Three new 2×2 MIMO array antennas are proposed, covering dual and multiple spectrum
bandwidths for WLAN (2.4/5.2/5.8 GHz) and WiMAX (3.5 GHz) applications. These designs
employ a combination of DGS and neutralization line methods to reduce the coupling caused by
the surface current in the ground plane and between the radiating antenna elements. The minimum
achieved isolation between the MIMO antennas is found to be better than 15 dB and in some
bands exceeds 30 dB. The matching impedance is improved and the correlation coefficient values
achieved for all three antennas are very low. In addition, the diversity gains over all spectrum
bands are very close to the ideal value (DG = 10 dB).
The forth proposed MIMO antenna is a compact dual-band MIMO antenna operating at
WLAN bands (2.4/5.2/5.8 GHz). The antenna structure consists of two concentric double square
rings radiating elements printed symmetrically. A new method is applied which combines the
defected ground structure (DGS) decoupling method with five parasitic elements to reduce the
coupling between the radiating antennas in the two required bands.
A metamaterial-based isolation enhancement structure is investigated in the fifth proposed
MIMO antenna design. This MIMO antenna consists of two dual-band arc-shaped radiating
elements working in WLAN and Sub-6 GHz 5th generation (5G) bands. The antenna placement
and orientation decoupling method is applied to improve the isolation in the second band while
four split-ring resonators (SRRs) are added between the radiating elements to enhance the
isolation in the first band.
All the designs presented in this thesis have been fabricated and measured, with the simulated
and measured results agreeing well in most cases.Higher Committee for Education Development in Iraq (HCED)
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Diameh, Yousef A. "The optimization of multiple antenna broadband wireless communications. A study of propagation, space-time coding and spatial envelope correlation in Multiple Input, Multiple Output radio systems". Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6361.
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This work concentrates on the application of diversity techniques and space time block coding for future mobile wireless communications.
The initial system analysis employs a space-time coded OFDM transmitter over a multipath Rayleigh channel, and a receiver which uses a selection combining diversity technique. The performance of this combined scenario is characterised in terms of the bit error rate and throughput. A novel four element QOSTBC scheme is introduced, it is created by reforming the detection matrix of the original QOSTBC scheme, for which an orthogonal channel matrix is derived. This results in a computationally less complex linear decoding scheme as compared with the original QOSTBC. Space time coding schemes for three, four and eight transmitters were also derived using a Hadamard matrix.
The practical optimization of multi-antenna networks is studied for realistic indoor and mixed propagation scenarios. The starting point is a detailed analysis of the throughput and field strength distributions for a commercial dual band 802.11n MIMO radio operating indoors in a variety of line of sight and non-line of sight scenarios. The physical model of the space is based on architectural schematics, and realistic propagation data for the construction materials. The modelling is then extended and generalized to a multi-storey indoor environment, and a large mixed site for indoor and outdoor channels based on the Bradford University campus.
The implications for the physical layer are also explored through the specification of antenna envelope correlation coefficients. Initially this is for an antenna module configuration with two independent antennas in close proximity. An operational method is proposed using the scattering parameters of the system and which incorporates the intrinsic power losses of the radiating elements. The method is extended to estimate the envelope correlation coefficient for any two elements in a general (N,N) MIMO antenna array. Three examples are presented to validate this technique, and very close agreement is shown to exist between this method and the full electromagnetic analysis using the far field antenna radiation patterns.
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Dia'meh, Yousef Ali. "The optimization of multiple antenna broadband wireless communications : a study of propagation, space-time coding and spatial envelope correlation in Multiple Input, Multiple Output radio systems". Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6361.
Pełny tekst źródłaStreszczenie:
This work concentrates on the application of diversity techniques and space time block coding for future mobile wireless communications. The initial system analysis employs a space-time coded OFDM transmitter over a multipath Rayleigh channel, and a receiver which uses a selection combining diversity technique. The performance of this combined scenario is characterised in terms of the bit error rate and throughput. A novel four element QOSTBC scheme is introduced, it is created by reforming the detection matrix of the original QOSTBC scheme, for which an orthogonal channel matrix is derived. This results in a computationally less complex linear decoding scheme as compared with the original QOSTBC. Space time coding schemes for three, four and eight transmitters were also derived using a Hadamard matrix. The practical optimization of multi-antenna networks is studied for realistic indoor and mixed propagation scenarios. The starting point is a detailed analysis of the throughput and field strength distributions for a commercial dual band 802.11n MIMO radio operating indoors in a variety of line of sight and non-line of sight scenarios. The physical model of the space is based on architectural schematics, and realistic propagation data for the construction materials. The modelling is then extended and generalized to a multi-storey indoor environment, and a large mixed site for indoor and outdoor channels based on the Bradford University campus. The implications for the physical layer are also explored through the specification of antenna envelope correlation coefficients. Initially this is for an antenna module configuration with two independent antennas in close proximity. An operational method is proposed using the scattering parameters of the system and which incorporates the intrinsic power losses of the radiating elements. The method is extended to estimate the envelope correlation coefficient for any two elements in a general (N,N) MIMO antenna array. Three examples are presented to validate this technique, and very close agreement is shown to exist between this method and the full electromagnetic analysis using the far field antenna radiation patterns.
25
Pan, Zhengang, i 潘振崗. "Generalized beamforming for downlink of multi-user MIMO systems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29636139.
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Narayanaswamy, Sriram Kizhakkemadam. "Queuing delay of multi-antenna multi-user wireless networks". Ann Arbor, Mich. : ProQuest, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3303954.
Pełny tekst źródłaStreszczenie:
Thesis (Ph.D. in Electrical Engineering)--S.M.U.Title from PDF title page (viewed Mar. 16, 2009). Source: Dissertation Abstracts International, Volume: 69-03, Section: B, page: 1842. Adviser: Dinesh Rajan. Includes bibliographical references.
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Almeida, Andrà Lima FÃrrer de. "Modelagem tensorial e processamento de sinais por sistemas de comunicaÃÃes de redes". Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2131.
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CoordenaÃÃo de AperfeiÃoamento de NÃvel SuperiorEm diversas aplicaÃÃes do processamento de sinais em sistemas de comunicaÃÃo sem-fio, o sinal recebido à de natureza multidimensional, possuindo uma estrutura algÃbrica multilinear. Neste contexto, a decomposiÃÃo tensorial PARAFAC tem sido utilizada em vÃrios trabalhos ao longo dos Ãltimos seis anos. Observa-se, entretanto, que decomposiÃÃes tensoriais generalizadas sÃo necessÃrias para modelar uma classe mais ampla de sistemas de comunicaÃÃo, caracterizada pela presenÃa de estruturas de transmissÃo mais complexas, por modelos de canal mais realistas, e por tÃcnicas de processamento de sinais mais eficientes no receptor. Esta tese investiga novas abordagens tensorias e suas aplicaÃÃes em modelagem de sistemas MIMO, equalizaÃÃo, separaÃÃo de sinais e estimaÃÃo paramÃtrica de canal. Inicialmente, duas novas decomposiÃÃes tensoriais (PARAFAC em blocos com restriÃÃes e CONFAC) sÃo desenvolvidas e estudadas em termos de identificabilidade. Em uma segunda parte do trabalho, novas aplicaÃÃes destas decomposiÃÃes tensoriais sÃo propostas. A decomposiÃÃo PARAFAC em blocos com restriÃÃes à aplicada, primeiramente, Âa modelagem unificada de sistemassuperamostrados, DS-CDMA e OFDM, com aplicaÃÃo em equalizaÃÃo multiusuÃria. Em seguida, esta decomposiÃÃo à utilizada na modelagem de sistemas de transmissÃo MIMO com espalhamento espaÃo-temporal e detecÃÃo conjunta. Em seguida, a decomposiÃÃo CONFAC à explorada na concepÃÃo de uma nova arquitetura generalizada de transmissÃo MIMO/CDMA que combina diversidade e multiplexagem. As propriedades de unicidade desta decomposiÃÃo permitem o uso do processamento nÃo-supervisionado no receptor, visando a reconstruÃÃo dos sinais transmitidos e a estimaÃÃo do canal. Na terceira e Ãltima parte deste trabalho, explora-se a decomposiÃÃo PARAFAC no contexto de duas aplicaÃÃes diferentes. Na primeira, uma nova estrutura de transmissÃo espaÃo-temporal-freqÃencial à proposta para sistemas MIMO multiportadora. A segunda aplicaÃÃo consiste em um novo estimador paramÃtrico para canais multipercursos.
In several signal processing applications for wireless communications, the received signal is multidimensional in nature and may exhibit a multilinear algebraic structure. In this context, the PARAFAC tensor decomposition has been the subject of several works in the past six years. However, generalized tensor decompositions are necessary for covering a wider class of wireless communication systems with more complex transmission structures, more realistic channel models and more efficient receiver signal processing. This thesis investigates tensor modeling approaches for multiple-antenna systems, channel equalization, signal separation and parametric channel estimation. New tensor decompositions, namely, the block-constrained PARAFAC and CONFAC decompositions, are developed and studied in terms of identifiability. First, the block-constrained PARAFAC decomposition is applied for a uniÂed tensor modeling of oversampled, DS-CDMA and OFDM systems with application to blind multiuser equalization. This decomposition is also used for modeling multiple-antenna (MIMO) transmission systems with block space-time spreading and blind detection, which generalizes previous tensor-based MIMO transmission models. The CONFAC decomposition is then exploited for designing new MIMO-CDMA transmission schemes combining spatial diversity and multiplexing. Blind symbol/code/channel recovery is discussed from the uniqueness properties of this decomposition. This thesis also studies new applications of third-order PARAFAC decomposition. A new space-time-frequency spreading system is proposed for multicarrier multiple-access systems, where this decomposition is used as a joint spreading and multiplexing tool at the transmitter using tridimensional spreading code with trilinear structure. Finally, we present a PARAFAC modeling approach for the parametric estimation of SIMO and MIMO multipath wireless channels with time-varying structure.
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Zainal, Abidin Intan. "Multi antenna multiplexing techniques in static wireless links". Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/841785/.
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In this digital era, the usage of smart phones and mobile devices is becoming a norm in society with mobile communication quickly transitioned from voice oriented transmission to picture transmission to a more complex live video streaming. This latest development has demanded more capacity and higher bandwidth in communication links. Static links, which are the focus of this thesis, are an integral part of this mobile system in delivering high capacity data transmission using backhauls or nomadic links. Multi polarised antennas with multiple-input multiple-output (MIMO) multiplexing can be employed to greatly enhance the capacity of a mobile system, especially at frequencies lower than 6 GHz, using their compact size. A practical antenna inherently exhibits elliptical polarisation though it may be designed to form linear or circular polarisation. Little attention has been given to this aspect of polarised waves as they have always been deemed as unwanted polarisation, although in practice, any antenna is elliptically polarised as it can never be perfectly circularly or linearly polarised. This work therefore aims to deliberately exploit this opportunity by forming antennas with elliptical polarisation to identify the advantages of doing so in order to improve orthogonality in comparison with linear polarisation. It was found that in order to achieve perfect orthogonality, it was more practical to set the magnitudes and phases of the co-polar and cross-polar linear components, which resulted in an improved co to cross polar ratio more than 20 dB better than linear polarisation in free space. A dual elliptically polarised antenna prototype was designed and evaluated in this work, which was evaluated both in free space and within an indoor measurement campaign. Results concluded that at short distances with low scattering in the channel and directional antennas, elliptically polarised antennas provide improved multiplexing gain over dual linear polarisations. Key words: Elliptical Polarisation, MIMO, Multiplexing, static wireless links, degrees of freedom, dual polarised antenna.
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Banister, Brian Clarke. "Feedback assisted multi-antenna transmission weight adaptation for wireless communications /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3061640.
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Hinton, Danielle A. (Danielle Ayodele) 1978. "Protocols for multi-antenna ad-hoc wireless networking in interference environments". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62416.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 231-242).
A fundamental question for the design of future wireless networks concerns the nature of spectrum management and the protocols that govern use of the spectrum. In the oligopoly model, spectrum is owned and centrally managed, and the protocols tend to reflect this centralized nature. In the common's model, spectrum is a public good, and protocols must support ad hoc communication. This work presents the design, tradeoffs and parameter optimization for a new protocol (Simultaneous Transmissions in Interference (STI-MAC)) for ad hoc wireless networks. The key idea behind the STI-MAC protocol is 'channel stuffing,' that is, allowing network nodes to more efficiently use spatial, time and frequency degrees of freedom. This is achieved in three key ways. First, 'channel stuffing' is achieved through multiple antennas that are used at the receiver to mitigate interference using Minimum-Mean-Squared-Error (MMSE) receivers, allowing network nodes to transmit simultaneously in interference limited environments. The protocol also supports the use of multiple transmit antennas to beamform to the target receiver. Secondly, 'channel stuffing' is achieved through the use of a control channel that is orthogonal in time to the data channel, where nodes contend in order to participate on the data channel. And thirdly, 'channel stuffing' is achieved through a protest scheme that prevents data channel overloading. The STI-MAC protocol is analyzed via Monte-Carlo simulations in which transmitter nodes are uniformly distributed in a plane, each at a fixed distance from their target receiver; and as a function of network parameters including the number of transmit and receive antennas, the distance between a transmitter-receiver pair (link-length), the average number of transmitters whose received signal is stronger at a given receiver than its target transmitter (link-rank), number of transmitter-receiver pairs, the distribution on the requested rate, the offered load, and the transmit scheme. The STI-MAC protocol is benchmarked relative to simulations of the 802.11(n) (Wi-Fi) protocol. The key results of this work show a 3X gain in throughput relative to 802.11(n) in typical multi-antenna wireless networks that have 20 transmitter-receiver pairs, a link-length of 10 meters, four receive antennas and a single transmit antenna. We also show a reduction in delay by a factor of two when the networks are heavily loaded. We find that the link-rank is a key parameter affecting STIMAC gains over Wi-Fi. In simulations of networks with 40 transmit-receiver pairs, link-rank of three, a link-length of 10 meters, and eight transmit and receive antennas in which the transmitter beamforms to its target receiver in its strongest target channel mode, we find gains in throughput of at least 5X over the 802.11(n) protocol.
by Danielle A. Hinton.
Ph.D.
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Janapsatya, Januar. "Switched-beam smart antenna system for indoor wireless LAN /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18419.pdf.
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Li, Ran. "A wireless clock distribution system using an external antenna". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011385.
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Guerra, Leonard. "IEEE 802.11b wireless LAN sensor system and antenna design". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001713.
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Carlsson, Erik. "Underwater Communications System with Focus on Antenna Design". Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121481.
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In this thesis the possibility of building an underwater communication system usingelectromagnetic waves has been explored. The focus became designing and testingan antenna even if the entire system has been outlined as well. The conclusion isthat using magnetically linked antennas in the near field it is a very real possibilitybut for long EM waves in the far field more testing needs to be done. This isbecause a lack of equipment and facilitates which made it hard to do the realworld testing for this implementation even if it should work in theory.
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Heffernan, Travis Jade. "Metamaterial Enhanced Wireless Power Transmission System". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1069.
Pełny tekst źródłaStreszczenie:
Nikolai Tesla's revolutionary experiments demonstrated the possible benefits of transmitting power wirelessly as early as 1891. Applications for the military, consumers, emergency personnel, remote sensors, and others use Tesla’s discovery of wireless power. Wireless power transmission (WPT) has the potential to be a common source of consumable energy, but it will only receive serious consideration if the transmit and receive systems are extremely efficient and capable of delivering usable amounts of power. Research has been conducted to improve the efficiency and performance of nearly every aspect of WPT systems, but the relatively new field of metamaterials (MTMs) has yet to play a dominate role in improving system performance. A gradient index (GRIN) MTM lens was designed using Ansoft’s High Frequency Structure Simulator (HFSS) to improve antenna gain and thereby increase WPT system performance. A simple WPT demonstration system using microstrip patch antennas (MPAs) confirmed the benefits of the GRIN MTM lens. The WPT demonstration system, MPAs, and GRIN MTM lens were constructed and experimentally tested near 2.45 GHz. The theoretical and experimental gain improvement of the MPA due to the GRIN MTM lens is 5.91 dB and 7.06 dB, respectively.
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Ban, K., M. Katayama, W. E. Stark, T. Yamazato i A. Ogawa. "Convolutionally Coded DS/CDMA System using Multi-Antenna Transmission". IEEE, 1997. http://hdl.handle.net/2237/7785.
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Macedo, Aleandro Soares. "Antenna sector-time division multiple access system for indoor wireless communications". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/NQ35234.pdf.
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Subramanian, Srikanth. "A multiple-antenna-multiple-equalizer system for CDMA indoor wireless systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32728.pdf.
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Khan, B. (Bilal). "Adaptive vehicular antenna system for extended range cellular access". Master's thesis, University of Oulu, 2016. http://urn.fi/URN:NBN:fi:oulu-201606092485.
Pełny tekst źródłaStreszczenie:
In this thesis, a steerable antenna system which is able to maintain high connectivity through beamforming towards the strongest base station signal is presented. Main objective of the thesis is to design an antenna system for vehicles operating in poor coverage region or even in no coverage region, in order to enable these vehicles to make a reliable communication link with far away base stations. To achieve this high performance antenna system, several antenna designs were considered and evaluated for their performance. This thesis provides an overview of different antenna designs considered and their pros and cons. Among these designs, the concept of stacked patch antenna was selected for prototype manufacturing because of its good performance in terms of bandwidth, efficiency, gain, impedance matching and ease of fabrication because of its simple structure. Stacked patch antenna was optimized for lower GSM band covering frequencies from 824 MHz to 960 MHz by using electromagnetic simulation software CST Microwave Studio.
Finally the stacked patch antenna was fabricated and measurements were performed. The results for both the prototype measurement and simulations are presented and compared. From the comparison, it is concluded that the manufactured antenna element prototype gives high performance as promised by simulation results and is suitable for the adaptive vehicular antenna system.
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Kiran, T. "Coding For Multi-Antenna Wireless Systems And Wireless Relay Networks". Thesis, 2006. https://etd.iisc.ac.in/handle/2005/399.
Pełny tekst źródłaStreszczenie:
Communication over a wireless channel is a challenging task because of the inherent fading effects. Any wireless communication system employs some form of diversity improving techniques in order to improve the reliability of the channel. This thesis deals with efficient code design for two different spatial diversity techniques, viz, diversity by employing multiple antennas at the transmitter and/or the receiver, and diversity through cooperative commu-
nication between users. In other words, this thesis deals with efficient code design for (1) multiple-input multiple-output (MIMO) channels, and (2) wireless relay channels. Codes for the MIMO channel are termed space-time (ST) codes and those for the relay channels are called distributed ST codes.
The first part of the thesis focuses on ST code construction for MIMO fading channel with perfect channel state information (CSI) at the receiver, and no CSI at the transmitter. As a measure of performance we use the rate-diversity tradeoff and the Diversity-Multiplexing Gain (D-MG) Tradeoff,
which are two different tradeoffs characterizing the tradeoff between the rate
and the reliability achievable by any ST code. We provide two types of code
constructions that are optimal with respect to the rate-diversity tradeoff; one is based on the rank-distance codes which are traditionally applied as codes for storage devices, and the second construction is based on a matrix representation of a cayley algebra. The second contribution in ST code constructions is related to codes with
a certain nonvanishing determinant (NVD) property. Motivation for these constructions is a recent result on the necessary and sufficient conditions for an ST code to achieve the D-MG tradeoff. Explicit code constructions satisfying these conditions are provided for certain number of transmit antennas.
The second part of the thesis focuses on distributed ST code construction for wireless relay channel. The transmission protocol follows a two-hop model wherein the source broadcasts a vector in the first hop and in the second hop the relays transmit a vector that is a transformation of the received vector by a relay-specific unitary transformation. While the source and relays do not have CSI, at the destination we assume two different scenarios (a) destina-
tion with complete CSI (b) destination with only the relay-destination CSI. For both these scenarios, we derive a Chernoff bound on the pair-wise error probability and propose code design criteria. For the first case, we provide explicit construction of distributed ST codes with lower decoding complexity compared to codes based on some earlier system models. For the latter case,
we propose a novel differential encoding and differential decoding technique and also provide explicit code constructions.
At the heart of all these constructions is the cyclic division algebra (CDA) and its matrix representations. We translate the problem of code construction in each of the above scenarios to the problem of constructing CDAs satisfying certain properties. Explicit examples are provided to illustrate each of these constructions.
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Kiran, T. "Coding For Multi-Antenna Wireless Systems And Wireless Relay Networks". Thesis, 2006. http://hdl.handle.net/2005/399.
Pełny tekst źródłaStreszczenie:
Communication over a wireless channel is a challenging task because of the inherent fading effects. Any wireless communication system employs some form of diversity improving techniques in order to improve the reliability of the channel. This thesis deals with efficient code design for two different spatial diversity techniques, viz, diversity by employing multiple antennas at the transmitter and/or the receiver, and diversity through cooperative commu-
nication between users. In other words, this thesis deals with efficient code design for (1) multiple-input multiple-output (MIMO) channels, and (2) wireless relay channels. Codes for the MIMO channel are termed space-time (ST) codes and those for the relay channels are called distributed ST codes.
The first part of the thesis focuses on ST code construction for MIMO fading channel with perfect channel state information (CSI) at the receiver, and no CSI at the transmitter. As a measure of performance we use the rate-diversity tradeoff and the Diversity-Multiplexing Gain (D-MG) Tradeoff,
which are two different tradeoffs characterizing the tradeoff between the rate
and the reliability achievable by any ST code. We provide two types of code
constructions that are optimal with respect to the rate-diversity tradeoff; one is based on the rank-distance codes which are traditionally applied as codes for storage devices, and the second construction is based on a matrix representation of a cayley algebra. The second contribution in ST code constructions is related to codes with
a certain nonvanishing determinant (NVD) property. Motivation for these constructions is a recent result on the necessary and sufficient conditions for an ST code to achieve the D-MG tradeoff. Explicit code constructions satisfying these conditions are provided for certain number of transmit antennas.
The second part of the thesis focuses on distributed ST code construction for wireless relay channel. The transmission protocol follows a two-hop model wherein the source broadcasts a vector in the first hop and in the second hop the relays transmit a vector that is a transformation of the received vector by a relay-specific unitary transformation. While the source and relays do not have CSI, at the destination we assume two different scenarios (a) destina-
tion with complete CSI (b) destination with only the relay-destination CSI. For both these scenarios, we derive a Chernoff bound on the pair-wise error probability and propose code design criteria. For the first case, we provide explicit construction of distributed ST codes with lower decoding complexity compared to codes based on some earlier system models. For the latter case,
we propose a novel differential encoding and differential decoding technique and also provide explicit code constructions.
At the heart of all these constructions is the cyclic division algebra (CDA) and its matrix representations. We translate the problem of code construction in each of the above scenarios to the problem of constructing CDAs satisfying certain properties. Explicit examples are provided to illustrate each of these constructions.
42
HUANG, YUN-HAO, i 黃昀皓. "Designs of Multi-band Antenna Arrays for 5G Wireless Communication System". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/fuxp3s.
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Baraani, Dastjerdi Mahmood. "High-Performance Multi-Antenna Wireless for 5G and Beyond". Thesis, 2020. https://doi.org/10.7916/d8-4q2c-1y14.
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Over the next decade, multi-antenna radios, including phased array and multiple-input-multiple-output (MIMO) radios, are expected to play an essential role in the next-generation of wireless networks. Phased arrays can reject spatial interferences and provide coherent beamforming gain, and MIMO technology promises to significantly enhance the system performance in the coverage, capacity, and user data rate through the beamforming or diversity/capacity gain which can substantially increase the range in wireless links, that are challenged from the transmitter (TX) power handling, receiver (RX) noise perspectives and a multi-path environment. Furthermore, the multi-user MIMO (MU-MIMO) can simultaneously serve multiple users which is vital for femtocell base stations and access points (AP).
Full-duplex (FD) wireless, namely simultaneous transmission and reception at the same frequency, is an emerging technology that has gained attention due to its potential to double the data throughput, as well as provide other benefits in the higher layers such as better spectral efficiency, reducing network and feedback signaling delays, and resolving hidden-node problems to avoid collisions. However, several challenges remain in the quest for the high-performance integrated FD radios. Transmitter power handling remains an open problem, particularly in FD radios that integrate a shared antenna interface. Secondly, FD operation must be achieved across antenna VSWR variations and a changing EM environment. Finally, FD must be extended to multi-antenna radios, including phased array and multi-input multi-output (MIMO) radios, as over the next decade, they are expected to play an essential role in the next generation of wireless networks. Multi-antenna FD operation, however, is challenged not only by the self-interference (SI) from each TX to its own RX but also cross-talk SI (CT-SI) between antennas. In this dissertation, first, a full-duplex phased array circulator-RX (circ.-RX) is proposed that achieves self-interference cancellation (SIC) through repurposing beamforming degrees of freedom (DoF) on TX and RX. Then, an FD MIMO circ.-RX is proposed that achieves SI and CT-SI cancellation (CT-SIC) through passive RF and shared-delay baseband (BB) canceller that addresses challenges associated with FD MIMO operation.
Wireless radios at millimeter-wave (mm-wave) frequencies enable the high-speed link for portable devices due to the wide-band spectrum available. Large-scale arrays are required to compensate for high path loss to form an mm-wave link. Mm-wave MIMO systems with digitization enable virtual arrays for radar, digital beamforming (DBF) for high mobility scenarios and spatial multiplexing. To preserve MIMO information, the received signal from each element in MIMO RX should be transported to ADC/DSP IC for DBF, and vice versa on the TX side. A large-scale array can be formed by tiling multiple mm-wave IC front-ends, and thus, a single-wire interface is desired between DSP IC and mm-wave ICs to reduce board routing complexity. Per-element digitization poses the challenge of handling high data-rate I/O in large-scale tiled MIMO mm-wave arrays. SERializer – DESerializer (SERDES) is traditionally being used as a high-speed link in computing systems and networks. However, SERDES results in a large area and power consumption. In this dissertation, a 60~GHz 4-element MIMO TX with a single-wire interface is presented that de-multiplexes the baseband signal of all elements and LO reference that are frequency-domain multiplexed on a single-wire coax cable.
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Khanafer, Ali. "Precoding and Resource Allocation for Multi-user Multi-antenna Broadband Wireless Systems". Thesis, 2010. http://hdl.handle.net/1807/25728.
Pełny tekst źródłaStreszczenie:
This thesis is targeted at precoding methods and resource allocation for the downlink of
fixed multi-user multi-antenna broadband wireless systems. We explore different utilizations
of precoders in transmission over frequency-selective channels. We first consider
the weighted sum-rate (WSR) maximization problem for multi-carrier systems using
linear precoding and propose a low complexity algorithm which exhibits near-optimal
performance. Moreover, we offer a novel rate allocation method that utilizes the signalto-
noise-ratio (SNR) gap to capacity concept to choose the rates to allocate to each
data stream. We then study a single-carrier transmission scheme that overcomes known
impairments associated with multi-carrier systems. The proposed scheme utilizes timereversal
space-time block coding (TR-STBC) to orthogonalize the downlink receivers and
performs the required pre-equalization using Tomlinson-Harashima precoding (THP).We
finally discuss the strengths and weaknesses of the proposed method.
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Chen, Xin-Xiong, i 陳信雄. "Development of Multi-Antenna System Applicable to Wireless Local Area Network Base Station". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/21404125855817411631.
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碩士國立臺灣科技大學
電機工程系
103
This thesis focuses on the development of multi-antenna systems applicable to wireless local area network base stations. The thesis consists of two parts. The first part is a six-antenna system, which uses slot antenna and invert-F antenna as antenna elements. To achieve space diversity, antennas are miniaturized by adding lump elements. Moreover, by adjusting antenna orientations, it produces differences in polarization and hence improves the isolation between adjacent antennas. Though adding lump element may deteriorate antenna efficiency, the fabricated prototype still shows radiation efficiency between 65 to 71% and is acceptable for projected uses. To test the diversity performance, an effective diversity gain measured systemis used to verify the good performance of the fabricated prototype in antenna diversity. The second part is an eight-antenna system. Two kinds of slot antennas are used as element antennas. The overall antenna system has a low-profile. To enhance the isolation among antennas, meandered slot are used to reduce antenna sizes. The eight antennas are arranged in a symmetrical fashion. Through the implementation and measurements, the fabricated prototype shows good performance in diversity. The antenna is suitable for WLAN base stations.
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Pollock, Tony Steven. "On Limits of Multi-Antenna Wireless Communications in Spatially Selective Channels". Phd thesis, 2003. http://hdl.handle.net/1885/47999.
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Multiple-Input Multiple-Output (MIMO) communications systems using multiantenna arrays simultaneously during transmission and reception have generated significant interest in recent years. Theoretical work in the mid 1990?s showed the potential for significant capacity increases in wireless channels via spatial multiplexing with sparse antenna arrays and rich scattering environments. However, in reality the capacity is significantly reduced when the antennas are placed close together, or the scattering environment is sparse, causing the signals received by different antennas to become correlated, corresponding to a reduction of the effective number of sub-channels between transmit and receive antennas. ¶ By introducing the previously ignored spatial aspects, namely the antenna array geometry and the scattering environment, into a novel channel model new bounds and fundamental limitations to MIMO capacity are derived for spatially constrained, or spatially selective, channels. A theoretically derived capacity saturation point is shown to exist for spatially selective MIMO channels, at which there is no capacity growth with increasing numbers of antennas. Furthermore, it is shown that this saturation point is dependent on the shape, size and orientation of the spatial volumes containing the antenna arrays along with the properties of the scattering environment. ¶ This result leads to the definition of an intrinsic capacity between separate spatial volumes in a continuous scattering environment, which is an upper limit to communication between the volumes that can not be increased with increasing numbers of antennas within. It is shown that there exists a fundamental limit to the information theoretic capacity between two continuous volumes in space, where using antenna arrays is simply one choice of implementation of a more general spatial signal processing underlying all wireless communication systems.
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Su, Student :. Hsuan-Jui, i 蘇炫睿. "Multi-Functions Active Antenna System a Wireless Repeater for the Reception of Digital TV Signals". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/76951911969908585595.
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碩士元智大學
通訊工程學系
98
This main purpose of this article is to develop a wireless repeater for TV reception. It is desired to increase the signal quality and signal strength at a frequency band of 500-600MHz. This antenna is integrated into a multi-function smart antenna system that is designed for WiFi communication 2.4GHz. The design concept is to use a pair of antennas that are used as receiving and transmitting antennas. In order to properly integrate them with the smart antenna system, the TV antennas utilize the support structures of system as a receiving antenna, and add a new antenna to transmit the amplified signal back into the space. To provide a proper isolation between these two antennas, polarization diversity was used, where the vertical and horizontal polarizations were used for the receiving and transmitting antennas. Wire antenna types were used. A RF circuit aiming to amplify the signals was designed using existing RF components. Numerical simulation and experimental measurement were performed and presented to validate the current design. Promising results and permance enhancement were obtained.
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Ho, Wen-Pin, i 何文彬. "Design of Multi-Band Antennas For Wireless Communication System". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/85334455254902181824.
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碩士逢甲大學
電機工程所
99
In this thesis, the designs of multiband antennas for wireless communication system are studied. Here, three different antennas structure for mobile application are investigated and discussed. A hybrid mobile device antenna with double-layer structure for multiband operation is initially proposed. It is able to cover the wireless applications such as GSM/DCS/DCS/UMTS/WLAN 2400. The main structure of this antenna is composed of two layers; the top layer of proposed antenna produces three resonance modes (at around 0.88, 0.97 and 1.18 GHz) with respect to three radiation strips. The bottom layer of proposed antenna produces three resonance modes (at around 1.38, 1.76 and 2.45 GHz) by embedding a T-shape open-ended slot into the rectangle radiation patch. The second proposed antenna is a compact size (15 mm × 40 mm) microstrip-fed printed planar inverted-F antenna (PIFA) for mobile applications. The main structure of this antenna is a simple double-folded PIFA with two wide open-ended radiating sections. By tuning the two wide open-ended radiating sections, optimum impedance matching and inclusion of UMTS band can be achieved. Compared to the previously proposed antenna, this antenna has the advantages such as planar structure, and additional operating band in the WLAN 5.2/5.8 and WiMAX. Finally, a coplanar printed antenna with inverted L-shape coupling feed is proposed. By using an inverted L-shape coupling feed and a meandered shorting strip, two wide operation bands are excited. Both the lower and upper operation band can cover LTE 700/GSM and DCS 1800/PCS 1900/UMTS/LTE 2300, respectively. To operate at LTE 2500 band, a technique of joining a parasitic stub around the feed point which excites a resonance mode at 2.72 GHz is introduced. This proposed antenna can be used as a multiband antenna operation for the application in fourth generation (4 G) wireless communication system. By comparing to the other wireless communication system, the 4G wireless system can provide faster transmission speed and more system capacity.
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Paredes, Riano Javier Mauricio. "Low-complexity space-time coding for multi-antenna systems and wireless relay networks". Phd thesis, 2009. https://tuprints.ulb.tu-darmstadt.de/1421/1/thesis.pdf.
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A rapidly growing demand on transmission rates, coverage and reliability for wireless communication systems has triggered an intensive research in the field of multi-antenna communications. The use of multi-antenna systems provides significant gains by making use of independent propagation paths between the transmitter and the receiver. Space-time coding has been recently proposed to exploit the benefits of the multi-antenna channels. In space-time code design, different tradeoffs have to be taken into account. Good codes should provide a high diversity gain and achieve the highest possible multiplexing gain. At the same time, the encoding/decoding complexity should remain as low as possible to enable computationally efficient signal processing. In this thesis, we propose high-rate high-performance space-time block coding schemes that achieve a significantly reduced maximum likelihood decoding complexity in comparison to other state-of-the-art space-time codes. In particular, we propose a 2x2 full-rate space-time code with non-vanishing determinants that achieves the optimal diversity-multiplexing gain tradeoff while using a fast maximum likelihood decoder. Furthermore, by extending the proposed strategy, we develop space-time codes for 3 and 4 transmit antennas. In certain cases, the use of multi-antenna systems can become impractical due to restrictions in hardware size and cost. As an alternative to create multi-path propagation environments, half-duplex wireless relay networks have emerged. In such networks, single antenna users cooperate to provide gains similar to that of the multi-antenna channel. Considering the initial restrictions, low-complexity distributed space-time coding schemes are required for relay systems. In the second part of the thesis, we develop a novel low-rate feedback-based distributed approach for cooperative transmission in relay networks that achieves the maximum diversity offered by the relay network, enjoys low-complexity maximum likelihood decoding, avoids long decoding delays and is applicable to any number of relays. The use of second-order channel statistics to design “long-term” power control weights is considered to further improve the performance of our approach in practical scenarios with channel links of different quality. Moreover, the proposed distributed space-time coding schemes are generalized to the non-coherent receiver case using differential transmission.
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Ho, Jaunty Tsun Yue. "Frequency-time-space correlation and its applications in multi-antenna systems". Phd thesis, 2004. http://hdl.handle.net/1885/150755.
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