Orientador: Michel Daoud Yacoub / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-23T14:27:26Z (GMT). No. of bitstreams: 1 Heinrich_RalphRobert_M.pdf: 7113070 bytes, checksum: 2a64f903bc44fb31b9ee53ef545bb24e (MD5) Previous issue date: 2013 / Resumo: Este projeto de pesquisa objetiva responder a algumas questões sistêmicas levantadas por ocasião do início do desenvolvimento do sistema LTE-450, parte integrante do projeto RASFA - Redes de Acesso Sem Fio Avançadas, conduzido pelo CPqD - Fundação Centro de Pesquisa e Desenvolvimento em Telecomunicações, com recursos do FUNTTEL - Fundo para o Desenvolvimento Tecnológico das Telecomunicações. Esse projeto visa, como um de seus objetivos, o desenvolvimento de um sistema de rádio acesso sem fio LTE-450, operando na faixa de 450 a 470 MHz, baseado na tecnologia LTE - Long Term Evolution. A faixa de 450 a 470 MHz está atribuída em base global desde 2007 para o Serviço Móvel, conforme identificado pela União Internacional de Telecomunicações na World Radiocommunication Conference 2007. A Anatel - Agência Nacional de Telecomunicações - publicou a nova destinação de uso para a faixa de 450 a 470 MHz em 20 de dezembro de 2010, através da Resolução n º 558. Várias ações vêm sendo empreendidas em apoio ao uso da faixa 450 a 470 MHz, para a prestação de serviços banda larga sem fio para áreas rurais, como consta do Programa Nacional de Telecomunicações Rurais, publicado pela Portaria 431/2009 do Ministério das Comunicações, e do Plano Nacional de Banda Larga, publicado em 13 de maio de 2010. Entende-se que a faixa de 450 a 470 MHz é ideal para a implantação de serviços de banda larga sem fio em áreas rurais, devido às suas características de propagação. Por outro lado, a base de conhecimento sobre o canal rádio em sistemas de rádio acesso móvel banda larga considera o uso, em áreas urbanas, de faixas de frequências situadas entre 850 MHz e 3500 MHz. São notórias as diferenças entre as características de propagação nessas faixas e nas faixas de UHF, principalmente quando a área de prestação do serviço deixa de ser a urbana e passa a ser a rural. Nesse sentido, alguns requisitos sistêmicos podem ser questionados e mesmo redimensionados. Esses requisitos foram aqui endereçados através de levantamento de dados em campo e posterior análise crítica contra a base de conhecimento disponível. São questões como a amplitude do desvanecimento seletivo e por despolarização, a intensidade do ruído impulsivo, os modelos de propagação aplicáveis à área rural e à faixa de UHF, a variação da perda de percurso com a altura da antena do terminal e a discriminação de polarização da antena do terminal / Abstract: This research project aims to answer some systemic issues raised during the early development of the LTE-450 radio access system, part of a project RASFA - Advanced Wireless Networks Access, led by CPqD Foundation - Center for Research and Development in Telecommunications with resources of FUNTTEL - Technological Development of Telecommunications Fund. This project aims, as one of its objectives, the development of a LTE-450 wireless system, operating in the 450-470 MHz band, based on LTE - Long Term Evolution technology. The 450-470 MHz band is allocated, on a global basis, since 2007 for Mobile Service, as identified by the International Telecommunication Union in the World Radiocommunication Conference 2007. Anatel - The Brazilian National Telecommunications Agency has published a new destination for the 450-470 MHz band on December 20, 2010, through Resolution No. 558. Several actions have been undertaken in support of the use of the 450-470 MHz band, to provide wireless broadband services to rural areas, as set out in the National Rural Telecommunications Plan, published by the Decree 431/2009 of the Ministry of Communications and the National Broadband Plan (PNBL), published on May 13, 2010. It is understood that the 450-470 MHz band is ideal for deploying wireless broadband services in rural areas, due to its propagation characteristics. On the other hand, the base of knowledge about the mobile broadband access radio systems channel, considering the use in urban areas, situated between 850 MHz and 3500 MHz bands have notable differences between the propagation characteristics of these bands and the UHF bands, especially when the area of service provision ceases to be the urban and goes to the rural areas. Thus, some systemic requirements can be questioned and even resized. These requirements are addressed here through field data gathering and subsequent critical analysis against the knowledge base available. These issues are such as the extent of selective fading and depolarization, the intensity of the impulse noise, the propagation models applicable to the rural area and the UHF band, the variation of the path loss with the height of the terminal antenna and of terminal antenna polarization discrimination / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

Submitted in fulfillment of the requirements of the Master of Technology Degree in Information Technology, Durban University of Technology, Durban, South Africa, 2014. / This dissertation reports on handover in downlink Long Term Evolution (LTE) networks. The LTE is seen as the technology that will bring about Fourth Generation (4G) mobile broadband experience. The necessity to maintain quality of service for delay sensitive data services and applications used by mobile users makes mobility and handover between base stations in the downlink LTE very critical. Unfortunately, several handover schemes in LTE are based on Reference Symbols Received Power (RSRP) which include measurement error due to limited symbols in downlink packets. However, prompt and precise handover decision cannot be based on inaccurate measurement. Therefore, the downlink LTE intra-system handover is studied with focus on user measurement report. The study centers on preparation stage of the LTE handover procedure. Two different types of physical layer filtering technique namely linear averaging and local averaging are focused upon among others investigated. The performance of LTE conventional physical layer filtering technique, linear filtering, is compared with an alternative technique called local averaging. The output of each physical layer filtering is then used for LTE standardized radio resource layer filtering (otherwise called L3 filtering). The analysis of results from handover decision is based on simulations performed in an LTE system-level simulator. The performance metrics for the results are evaluated in terms of overall system and mobility-related performance. The system performance is based on spectral efficiency and throughput while mobility-related performance is based on handover failure. The performance comparison of the results shows that local averaging technique provides improved system performance of about 51.2 % for spectral efficiency and 42.8% cell-edge throughput for high speed users. Local averaging also produces a reduction of about 26.95% in average number of handover failure when L 3 filtering is applied for low speed mobile terminal. This result confirms that both averaging techniques are suitable for LTE network. Moreover, in the case of high mobility local averaging tends to be better than linear averaging.

This thesis presents the design of a communication system (PRCS) which improves on all aspects of the current state of the art 4G communication system Long Term Evolution (LTE) including peak to average power ratio (PAPR), data reliability, spectral efficiency and complexity using the most recent state of the art research in the field combined with novel implementations. This research is relevant and important to the field of electrical and communication engineering because it provides benefits to consumers in the form of more reliable data with higher speeds as well as a reduced burden on hardware original equipment manufacturers (OEMs). The results presented herein show up to a 3 dB reduction in PAPR, less than 10-5 bit errors at 7.5 dB signal to noise ratio (SNR) using 4QAM, up to 3 times increased throughput in the uplink mode and 10 times reduced channel coding complexity.

Poussé par la demande croissante de services à haut débit sans fil, Long Term Evolution (LTE) a émergé comme une solution prometteuse pour les communications mobiles. Dans plusieurs pays à travers le monde, la mise en oeuvre de LTE est en train de se développer. LTE offre une architecture tout-IP qui fournit des débits élevés et permet une prise en charge efficace des applications de type multimédia. LTE est spécifié par le 3GPP ; cette technologie fournit une architecture capable de mettre en place des mécanismes pour traiter des classes de trafic hétérogènes comme la voix, la vidéo, les transferts de fichier, les courriers électroniques, etc. Ces classes de flux hétérogènes peuvent être gérées en fonction de la qualité de service requise mais aussi de la qualité des canaux et des conditions environnementales qui peuvent varier considérablement sur une courte échelle de temps. Les standards du 3GPP ne spécifient pas l’algorithmique de l’allocation des ressources du réseau d’accès, dont l’importance est grande pour garantir performance et qualité de service (QoS). Dans cette thèse, nous nous focalisons plus spécifiquement sur la QoS de LTE sur la voie descendante. Nous nous concentrons alors sur la gestion des ressources et l’ordonnancement sur l’interface radio des réseaux d’accès. Dans une première partie, nous nous sommes intéressés à des contextes de macro-cellules. Le premier mécanisme proposé pour l’allocation des ressources combine une méthode de jetons virtuels et des ordonnanceurs opportunistes. Les performances obtenues sont très bonnes mais n’assurent pas une très bonne équité. Notre seconde proposition repose sur la théorie des jeux, et plus spécifiquement sur la valeur de Shapley, pour atteindre un haut niveau d’équité entre les différentes classes de services au détriment de la qualité de service. Cela nous a poussé, dans un troisième mécanisme, à combiner les deux schémas. La deuxième partie de la thèse est consacrée aux femto-cellules (ou femtocells) qui offrent des compléments de couverture appréciables. La difficulté consiste alors à étudier et à minimiser les interférences. Notre premier mécanisme d’atténuation des interférences est fondé sur le contrôle de la puissance de transmission. Il fonctionne en utilisant la théorie des jeux non coopératifs. On effectue une négociation constante entre le débit et les interférences pour trouver un niveau optimal de puissance d’émission. Le second mécanisme est centralisé et utilise une approche de division de la bande passante afin d’obliger les femtocells à ne pas utiliser les mêmes sous-bandes évitant ainsi les interférences. Le partage de bande passante et l’allocation sont effectués en utilisant sur la théorie des jeux (valeur de Shapley) et en tenant compte du type d’application. Ce schéma réduit les interférences considérablement. Tous les mécanismes proposés ont été testés et évalués dans un environnement de simulation en utilisant l’outil LTE-Sim au développement duquel nous avons contribué. / Driven by the growing demand for high-speed broadband wireless services, Long term Evolution (LTE) technology has emerged as a competitive alternative to mobile communications solution. In several countries around the world, the implementation of LTE has started. LTE offers an IP-based framework that provides high data rates for multimedia applications. Moreover, based on the 3GPP specifications, the technology provides a set of built in mechanisms to support heterogeneous classes of traffic including data, voice and video, etc. Supporting heterogeneous classes of services means that the traffic is highly diverse and has distinct QoS parameters, channel and environmental conditions may vary dramatically on a short time scale. The 3GPP specifications leave unstandardized the resource management and scheduling mechanisms which are crucial components to guarantee the QoS performance for the services. In this thesis, we evaluate the performance and QoS in LTE technology. Moreover, our research addresses the resource management and scheduling issues on the wireless interface. In fact, after surveying, classifying and comparing different scheduling mechanisms, we propose three QoS mechanisms for resource allocation in macrocell scenarios focused on real time services and two mechanisms for interference mitigation in femtocell scenarios taking into account the QoS of real time services. Our first proposed mechanism for resource allocation in macrocell scenarios combines the well known virtual token (or token buckets) method with opportunistic schedulers, our second scheme utilizes game theory, specifically the Shapley value in order to achieve a higher fairness level among classes of services and our third mechanism combines the first and the second proposed schemes. Our first mechanism for interference mitigation in femtocell scenarios is power control based and works by using non cooperative games. It performs a constant bargain between throughput and SINR to find out the optimal transmit power level. The second mechanism is centralised, it uses a bandwidth division approach in order to not use the same subbands to avoid interference. The bandwidth division and assignation is performed based on game theory (Shapley value) taking into account the application bitrate . This scheme reduces interference considerably and shows an improvement compared to other bandwidth division schemes. All proposed mechanism are performed in a LTE simulation environment. several constraints such as throughput, Packet Loss Ratio, delay, fairness index, SINR are used to evaluate the efficiency of our schemes

Channel assignment in multi-radio networks is a topic of great importance because the use of multiple channels and multiple radios reduces interference and increases the network throughput. The goal of our research is to design algorithms that maximize the use of available resources while providing robustness to primary users that could reclaim one or more channels. Our algorithms could be used in ad hoc networks, mesh networks, and sensor networks where nodes are equipped with multiple radios. We design algorithms for channel assignment which provide robustness to primary users without assuming an accurate primary user behavior model. We also compute bounds for capacity in grid networks and discuss how the capacity of a network changes when multiple channels are available. Since preserving energy is very important in wireless networks, we focus on algorithms that do not require powerful resources and which use a reduced number of messages. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

In wireless communication, the nonlinearity of a radio frequency (RF) power amplifier is an important issue for power amplifier designers. Since the nonlinearity is generated by the properties of physical components, it is hard to avoid it in producing power amplifiers. Power amplifier designers should know about the nonlinearity in order to compensate for it. A two-tone test is a relatively widely used method to measure the nonlinearity of a power amplifier, which means the third order intercept point (IP3) can be measured from the two-tone test. Through the two-tone test, researchers have proposed some formulae to present what the amplified Code Division Multiple Access (CDMA) signal is like. They derived formulae in terms of output power, bandwidth, IP3, and IP5 to express the amplified CDMA signal and further to Orthogonal Frequency Division Multiplexing (OFDM) signals. With the development of wireless communication, researchers put their interest increasingly in Multiple Input Multiple Output (MIMO) systems. A formula expressing amplified dual two-tone signals has been proposed. In their research, they discussed what the expressions of intermodulation and cross modulation are and what their locations are. In this research, dual band LTE-Advanced signals, whose modulation is OFDM are utilized, which means this research proposes a formula expression about the power spectrum of dual-band LTE-Advanced signals. Intermodulation and cross modulation caused by nonlinearity of power amplifiers are then specially discussed. This study will help RF designers to continuously compensate for them.

<p>Efficient radio resource management is of paramount importance for achieving the high bit rates targeted by the 3GPP for the 3GPP Long-Term Evolution. The radio air interface must be able to provide both high peak bit rates and acceptable cell-edge bit rates. This thesis therefore investigates three methods which try to combine the peak bit rate of a reuse-1 system with the cell-edge bit rate of a reuse-3 system in an OFDM-based downlink. These methods are soft frequency reuse, reuse partitioning and one variation of soft frequency reuse, reuse-1 with prioritization.</p><p>In static simulations with one user per cell and a system load of 100 percent, a Shannon capacity gain of up to 18 percent at the 10th percentile is shown with reuse partitioning compared to a reuse-1 system. This gain comes coupled with a loss of only 5 percent at the median. Soft frequency reuse is also investigated statically and shows a 13 percent gain at the 10th percentile compared to a reuse-1 system. Having a lower 10th percentile gain than reuse partitioning, it also shows a slightly smaller loss of 4 percent at the median and a much smaller loss at the 90th percentile.</p><p>Dynamic simulations with a traffic model and multiple users per cell offer a more realistic scenario and show that the proposed intercell interference management methods do not provide the same throughput gains in the dynamic case at low system loads. If interference is not an issue, interference coordination is still costly in terms of limiting bandwidth and/or decreasing the scheduling gain, but provides no significant interference reduction. At low system loads, reuse-1 is therefore the best scheme although interference coordination might prove necessary to provide edge-user throughput at high loads. For such purposes, soft frequency reuse is shown to be a potential candidate and although not investigated in a dynamic setting, reuse partitioning is believed to have similar performance. The traffic model chosen in this thesis only allows study of low system loads but at these loads, soft frequency reuse performs promisingly close to a reuse-1 system.</p>

<p>The advanced signal processing systems of today require extreme data throughput and low power consumption. The only way to accomplish this is to use parallel processor architecture.</p><p>The aim of this thesis was to evaluate the use of parallel processor architecture in baseband signal processing. This has been done by implementing three demanding algorithms in LTE on Ambric Am2000 family Massively Parallel Processor Array (MPPA). The Ambric chip is evaluated in terms of computational performance, efficiency of the development tools, algorithm and I/O mapping.</p><p>Implementations of Matrix Multiplication, FFT and Block Interleaver were performed. The implementation of algorithms shows that high level of parallelism can be achieved in MPPA especially on complex algorithms like FFT and Matrix multiplication. Different mappings of the algorithms are compared to see which best fit the architecture.</p>

Efficient radio resource management is of paramount importance for achieving the high bit rates targeted by the 3GPP for the 3GPP Long-Term Evolution. The radio air interface must be able to provide both high peak bit rates and acceptable cell-edge bit rates. This thesis therefore investigates three methods which try to combine the peak bit rate of a reuse-1 system with the cell-edge bit rate of a reuse-3 system in an OFDM-based downlink. These methods are soft frequency reuse, reuse partitioning and one variation of soft frequency reuse, reuse-1 with prioritization. In static simulations with one user per cell and a system load of 100 percent, a Shannon capacity gain of up to 18 percent at the 10th percentile is shown with reuse partitioning compared to a reuse-1 system. This gain comes coupled with a loss of only 5 percent at the median. Soft frequency reuse is also investigated statically and shows a 13 percent gain at the 10th percentile compared to a reuse-1 system. Having a lower 10th percentile gain than reuse partitioning, it also shows a slightly smaller loss of 4 percent at the median and a much smaller loss at the 90th percentile. Dynamic simulations with a traffic model and multiple users per cell offer a more realistic scenario and show that the proposed intercell interference management methods do not provide the same throughput gains in the dynamic case at low system loads. If interference is not an issue, interference coordination is still costly in terms of limiting bandwidth and/or decreasing the scheduling gain, but provides no significant interference reduction. At low system loads, reuse-1 is therefore the best scheme although interference coordination might prove necessary to provide edge-user throughput at high loads. For such purposes, soft frequency reuse is shown to be a potential candidate and although not investigated in a dynamic setting, reuse partitioning is believed to have similar performance. The traffic model chosen in this thesis only allows study of low system loads but at these loads, soft frequency reuse performs promisingly close to a reuse-1 system.

Evolutionary innovations often arise from complex genetic and ecological interactions, which can make it challenging to understand retrospectively how a novel trait arose. In a long-term experiment, Escherichia coli gained the ability (Cit⁺ ) to utilize abundant citrate in the growth medium after ~31,500 generations of evolution. Exploiting this previously untapped resource was highly beneficial: later Cit⁺ variants achieve a much higher population density in this environment. All Cit⁺ individuals share a mutation that activates aerobic expression of the citT citrate:C₄-dicarboxylate antiporter, but this mutation confers only an extremely weak Cit⁺ phenotype on its own. To determine which of the other >70 mutations in early Cit⁺ clones were needed to take full advantage of citrate, we developed a Recursive Genome-Wide Recombination and Sequencing (REGRES) method and performed genetic backcrosses to purge mutations not required for Cit⁺ from an evolved strain. We discovered a mutation that increased expression of the dctA C₄-dicarboxylate transporter greatly enhanced the Cit⁺ phenotype after it evolved, implicating the intracellular supply of succinate or other C₄-dicarboxylates to be a critical factor for the expression of the phenotype. The activity level of citrate synthase (CS), encoded by the gltA gene, was also found to be important for Cit⁺. A mutation to gltA (gltA1) occurred before the evolution of Cit⁺ and led to an increase in CS activity by diminishing allosteric inhibition by NADH. This mutation was found to be deleterious for high-level citrate utilization, a situation that was remedied shortly after the evolution of Cit⁺ by the evolution of compensatory mutations to gltA which decreased CS activity. We speculate that the gltA1 mutation may have been important to 'potentiate' the evolution of a weak Cit⁺ phenotype by increasing succinate production via an upregulated glyoxylate pathway but that as cells became able to import succinate by virtue of the dctA mutation that this pathway became maladaptive, prompting this evolutionary reversal. Overall, our characterization of this metabolic innovation highlights the degree to which interactions between alleles shape the evolution of complex traits and emphasizes the need for novel whole-genome methods to explore such relationships.