6 research outputs found

    Novas arquiteturas para transmissores digitais flexíveis e de banda larga

    Get PDF
    Next generation of wireless communication (5G) devices must achieve higher data rates, lower power consumption and better coverage by making a more efficient use of the RF spectrum and adopting highly exible radio architectures. To meet these requirements, the development of new radio devices will be far more complex and challenging than their predecessors. The future of radio communications have a twofold evolution, being one the low power consumption and the other the adaptability and intelligent use of the available resources. Conventional approaches for the radio physical layer are not capable to cope with the new demand for multi-band, multi-standard radio signals and present an inefficient and expensive solution for simultaneous transmission of multiple and heterogeneous radio signals. Digital radio transmitters have been presented as a solution for a newer and more exible architecture for future radios. All-digital transmitters use a completely digital implementation of the entire radio datapath from the baseband processing to the digital RF up-conversion. This concept bene ts from the use of highly integrated hardware together with a strong radio digitalization, motivated by the exibility and high performance from cognitive and software defi ned radio. However, such devices are still far from a massive deployment in most of communication scenarios due to some limiting factors that hinder their use. This PhD thesis aims to the development of novel radio architectures and ideas based on all-digital transmitters capable of improving the adaptability and use intelligently the available resources for software de ned and cognitive radio systems. The focus of this thesis is on the improvement of some of the common limitations for all-digital transmitters such as power efficiency, bandwidth, noise-shaping and exibility while using efficient and adaptable digital architectures. In the initial part of the thesis a review of the state-of-the-art is presented showing the most common digital transmitter architectures as well as their major bene ts and key limitations. A comparative analysis of such architectures is made considering their power and spectral efficiency, exibility, performance and cost. Following this initial analysis, the work developed on the course of this PhD is presented and discussed. The initial focus is on the improvement of all-digital transmitters bandwidth trough the study and use of parallel processing techniques capable of greatly improve common bandwidth values presented in the state-of-the-art. The presented work has resulted in several publications where FPGA-based architectures use parallel digital processing techniques to improve the system's bandwidth by a factor higher than 10. Other fundamental contribution of this thesis is focused on the pulsedtransmitters coding efficiency. In this section of the thesis, a method is presented showing the reduction of the quantization noise created by low amplitude resolution digital transmitters using multiple combined pulsedtransmitters to cancel the noise in speci c frequencies. This work has resulted in two main publications that showed how to increase the coding efficiency of the pulse-transmitters as well as the overall efficiency of the transmission system. Lastly, new-noise shaping methods are presented in order to develop new and more exible architectures for all-digital transmitters. The methods presented use new quantization processes that allow for the shaping of the quantization noise produced in pulsed-transmitters while using very simple and adaptable architectures. With these new techniques, it is possible to adjust the noise frequency distribution and deliberately change the noise shape in order to change some of the transmitter's characteristics such as central frequency or bandwidth. The work presented on this thesis has shown promising improvements to the all-digital transmitters' state-of-the-art, either in simulations and laboratory prototype measurements. It has contributed to advance the state-of-the-art in agile and power efficient all-digital RF transmitters with multi-mode and multi-channel capabilities and the improvement of the transceiver's bandwidth enabling the development of true software de ned and cognitive radio systemsA próxima geração de comunicações sem os (5G) exigirá taxas de transmissão mais elevadas, maior efi ciência energética e uma melhor cobertura fazendo um uso mais efi ciente do espectro de radiofrequência e adotando o uso de arquiteturas rádio mais flexíveis. Para cumprir tais requisitos, o desenvolvimento de novos dispositivos rádio será substancialmente mais complexo do que nas gerações anteriores. O futuro das comunicações rádio depende maioritariamente de dois fatores; o baixo consumo de potência e o uso inteligente dos recursos e tecnologias disponíveis. As abordagens convencionais para a camada física dos sistemas rádio não são as mais adequadas para lidar com a necessidade de dispositivos multi-banda e que usem múltiplos standards, por serem soluções inefi cientes e demasiado caras para esse efeito. Os transmissores rádio completamente digitais têm vindo a ser apresentados na literatura como uma solução inovadora e mais flexível para a implementação dos futuros sistemas de rádio. Os transmissores completamente digitais apresentam uma implementação da cadeia de processamento rádio, desde a banda-base até à conversão para RF, completamente constituída por lógica digital. Este conceito tira partido da vasta integração alcançada nas arquiteturas digitais, juntamente com a flexibilidade proveniente da digitalização das arquiteturas rádio que já se encontra em curso com a evolução dos rádios cognitivos e definidos por software. No entanto, devido a algumas limitações inerentes à tecnologia, este tipo de transmissores ainda não é amplamente utilizado na maioria dos sistemas. Esta tese de doutoramento propõe e avalia novas arquiteturas para transmissores completamente digitais, bem como novas técnicas de processamento de sinal que possam beneficiar das tecnologias de implementação existentes (e.g. FPGAs) por forma a construir novos transmissores digitais de forma eficiente e flexível. O objetivo desta tese é reduzir as limitações atuais ainda presentes neste tipo de transmissores, nomeadamente as relacionadas com a eficiência, largura de banda, cancelamento de ruído e falta de flexibilidade. Na parte inicial desta tese é realizada a revisão do estado da arte das diversas topologias de transmissores digitais bem como as suas principais vantagens e limitações técnicas. É também feita uma análise comparativa das diversas técnicas apresentadas em termos da sua eficiência energética, flexibilidade, desempenho e custo. De seguida, é apresentado o trabalho desenvolvido no contexto desta tese de doutoramento, seguindo-se uma discussão focada na resolução das atuais limitações deste tipo de transmissores. A primeira parte foca-se no uso de técnicas de processamento paralelo de sinal, por forma a suportar sinais de largura de banda mais elevada que os reportados no atual estado da arte. O trabalho desenvolvido e publicado baseia-se no uso de arquiteturas implementadas em FPGA que contribuíram para um aumento da largura de banda num fator de aproximadamente dez vezes. Outra das contribuições fundamentais desta tese consiste no aumento da eficiência do sistema através da melhoria da eficiência de codificação do sinal pulsado produzido. Com base no uso de múltiplos transmissores pulsados, e apresentado um esquema de combinação construtiva e destrutiva de sinais para a redução do ruído de quantização proveniente das técnicas de processamento de sinal pulsado usadas. Este trabalho resultou em duas importantes publicações que mostram que a melhoria da eficiência de codificação do sinal pode ser utilizada de forma a obter uma maior eficiência energética do transmissor. Por ultimo, são apresentadas diversas técnicas para a conversão dos sinais banda-base em sinais RF pulsados. As propostas apresentadas permitem o uso de uma arquitetura de hardware simplista, mas configurável por software, o que a torna bastante flexível. Com o uso desta arquitetura e possível alterar em pleno funcionamento a frequência central bem como a largura de banda e resposta do conversor pulsado. O trabalho apresentado nesta tese demonstra alguns dos melhoramentos no estado da arte para transmissores r adio completamente digitais, baseando os resultados obtidos não apenas em simulações mas também na implementação e medidas realizadas sobre protótipos laboratoriais. O trabalho desenvolvido no âmbito desta tese contribuiu com avanços na implementação de transmissores ageis, eficientes, com maior largura de banda e capazes de transmissão em múltiplas bandas com recurso a múltiplos protocolos, abrindo caminho para o desenvolvimento de novos rádios cognitivos e definidos por softwareFCT, FSEPrograma Doutoral em Engenharia Eletrotécnic

    Broadband Direct RF Digitization Receivers

    Full text link

    Digital Complex Delta–Sigma Modulators With Highly Configurable Notches for Multi-Standard Coexistence in Wireless Transmitters

    No full text
    International audienceThis paper presents a complex delta-sigma modu-lator (CDSM) designed for integration in a digital transmitter chain targeting multi-standard coexistence with nearby receivers. The use of a DSM has the advantage of increased performance in terms of signal-to-noise-ratio in the band of interest. However, the resulting out-of-band noise becomes an issue for multi-standard coexistence, thus increasing the complexity of the subsequent filtering stage. This constraint could be relaxed in the DSM stage, by placing a complex zero near the frequency band, where a low noise level is needed. This is achieved by cross coupling the in-phase (I) and quadrature (Q) channels, thus obtaining a CDSM. A review of known design methods for CDSM revealed limitations regarding the poles/zeros optimization, and the configurability of the complex zeros placement. The proposed architecture introduces two additional cross couplings from the I and Q quantizers outputs in order to decorrelate the zeros placement and the poles optimization problem. Hence, the improved CDSM can be implemented using existing optimization tools, which reduces considerably the number of iterations and the computational effort. In addition, the resulting modulator can target different coexistence scenarios without the need of redesign, unlike other known methods. Simulation results show a noise level reduction of approximately 20-30-dB near specific frequency bands by the proposed CDSM scheme with respect to standard DSM. Finally, we show an efficient coarse/fine configurability mechanism, which is obtained when introducing additional delays in the cross-coupling paths. Index Terms-Delta sigma modulator (DSM), complex delta sigma modulator (CDSM), finite impulse response (FIR), multi-standard coexistence, digital transmitter

    Systematic Approaches for Telemedicine and Data Coordination for COVID-19 in Baja California, Mexico

    Get PDF
    Conference proceedings info: ICICT 2023: 2023 The 6th International Conference on Information and Computer Technologies Raleigh, HI, United States, March 24-26, 2023 Pages 529-542We provide a model for systematic implementation of telemedicine within a large evaluation center for COVID-19 in the area of Baja California, Mexico. Our model is based on human-centric design factors and cross disciplinary collaborations for scalable data-driven enablement of smartphone, cellular, and video Teleconsul-tation technologies to link hospitals, clinics, and emergency medical services for point-of-care assessments of COVID testing, and for subsequent treatment and quar-antine decisions. A multidisciplinary team was rapidly created, in cooperation with different institutions, including: the Autonomous University of Baja California, the Ministry of Health, the Command, Communication and Computer Control Center of the Ministry of the State of Baja California (C4), Colleges of Medicine, and the College of Psychologists. Our objective is to provide information to the public and to evaluate COVID-19 in real time and to track, regional, municipal, and state-wide data in real time that informs supply chains and resource allocation with the anticipation of a surge in COVID-19 cases. RESUMEN Proporcionamos un modelo para la implementación sistemática de la telemedicina dentro de un gran centro de evaluación de COVID-19 en el área de Baja California, México. Nuestro modelo se basa en factores de diseño centrados en el ser humano y colaboraciones interdisciplinarias para la habilitación escalable basada en datos de tecnologías de teleconsulta de teléfonos inteligentes, celulares y video para vincular hospitales, clínicas y servicios médicos de emergencia para evaluaciones de COVID en el punto de atención. pruebas, y para el tratamiento posterior y decisiones de cuarentena. Rápidamente se creó un equipo multidisciplinario, en cooperación con diferentes instituciones, entre ellas: la Universidad Autónoma de Baja California, la Secretaría de Salud, el Centro de Comando, Comunicaciones y Control Informático. de la Secretaría del Estado de Baja California (C4), Facultades de Medicina y Colegio de Psicólogos. Nuestro objetivo es proporcionar información al público y evaluar COVID-19 en tiempo real y rastrear datos regionales, municipales y estatales en tiempo real que informan las cadenas de suministro y la asignación de recursos con la anticipación de un aumento de COVID-19. 19 casos.ICICT 2023: 2023 The 6th International Conference on Information and Computer Technologieshttps://doi.org/10.1007/978-981-99-3236-

    Using MapReduce Streaming for Distributed Life Simulation on the Cloud

    Get PDF
    Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

    The Music Sound

    Get PDF
    A guide for music: compositions, events, forms, genres, groups, history, industry, instruments, language, live music, musicians, songs, musicology, techniques, terminology , theory, music video. Music is a human activity which involves structured and audible sounds, which is used for artistic or aesthetic, entertainment, or ceremonial purposes. The traditional or classical European aspects of music often listed are those elements given primacy in European-influenced classical music: melody, harmony, rhythm, tone color/timbre, and form. A more comprehensive list is given by stating the aspects of sound: pitch, timbre, loudness, and duration. Common terms used to discuss particular pieces include melody, which is a succession of notes heard as some sort of unit; chord, which is a simultaneity of notes heard as some sort of unit; chord progression, which is a succession of chords (simultaneity succession); harmony, which is the relationship between two or more pitches; counterpoint, which is the simultaneity and organization of different melodies; and rhythm, which is the organization of the durational aspects of music
    corecore