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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

SDR radar demonstrator using OFDM-modulation / SDR radardemonstrator med OFDM-modulation

Larsson, Oskar, Karlsson, Jimmy January 2009 (has links)
<p>Today radars are used to measure the distance to almost anything. It is used to determine the position of airplanes as well as the level of an oiltank. To achieve high precision in level gauging radars high quality components are demanded. This makes them expensive.</p><p>In this project we evaluate the possibility to use relatively cheap components, used in radio communication, to measure distances with an OFDM-modulated signal. The components are cheap due to large production volumes rather than low performance.</p><p>To do this we started with working out the theory needed for length estimation. At our disposal we had the SDR SFF Development Platform from Lyrtech. A simulation model of the platform was built in MatLab. This model was used to verify the theory developed. Finally our algorithms was implemented on the development platform.</p><p>Both simulations and real life measurements show that OFDM can be used to measure distances. Even though the hardware used in this project is not dedicated for this application we managed to perform measurements with good accuracy at short range. We believe that with more suitable hardware OFDM-radars will be able to compete with todays high end level gauging radars at all ranges.</p> / <p>Nu för tiden används radar för att mäta avstånd i en rad olika sammanhang. Det används till allt från att bestämma positionen på flygplan till att mäta nivån i oljetankar. För att uppnå den höga precision som krävs vid nivåmätning ställs höga krav på de ingående komponenterna. Detta gör att radarn blir dyr.</p><p>I detta examensarbete utvärderar vi möjligheten att använda relativt billiga komponenter, som används inom radiokommunikation, för att mäta avstånd med hjälp av en OFDM-modulerad signal. Dessa komponenter är billiga till följd av stora tillverkningsvolymer, inte för att de är dåliga.</p><p>Till att börja med tog vi fram den teori som behövdes för att skatta avstånd. Till vårt förfogande hade vi Lyrtechs SDR SFF Developmemt Platform. En simuleringsmodell av platformen gjordes i MatLab vilken användes för att verifiera teorin. Slutligen implementerades algoritmerna på utvecklingsplattformen.</p><p>Både simuleringar och riktiga mätningar visar att OFDM kan användas för att mäta avstånd. Trots att hårdvaran som användts under examensarbetet inte är anpassad för avståndsmätning blev mätresultaten goda för korta avstånd. Vi är övertygade om att med en, för ändamålet, mer anpassad hårdvara kommer en OFDM-radar upppnå samma precision som dagens högpresterande nivåmätareäven för längre avstånd.</p>
102

Design of Programmable Baseband Processors

Tell, Eric January 2005 (has links)
The world of wireless communications is under constant change. Radio standards evolve and new standards emerge. More and more functionality is put into wireless terminals. E.g. mobile phones need to handle both second and third generation mobile telephony as well as Bluetooth, and will soon also support wireless LAN functionality, reception of digital audio and video broadcasting, etc. These developments have lead to an increased interest in software defined radio (SDR), i.e. radio devices that can be reconfigured via software. SDR would provide benefits such as low cost for multi-mode devices, reuse of the same hardware in different products, and increased product life time via software updates. One essential part of any software defined radio is a programmable baseband processor that is flexible enough to handle different types of modulation, different channel coding schemes, and different trade-offs between data rate and mobility. So far, programmable baseband solutions have mostly been used in high end systems such as mobile telephony base stations since the cost and power consumption have been considered too high for handheld terminals. In this work a new low power and low silicon area programmable baseband processor architecture aimed for multi-mode terminals is presented. The architecture is based on a customized DSP core and a number of hardware accelerators connected via a configurable network. The architecture offers a good tradeoff between flexibility and performance through an optimized instruction set, efficient hardware acceleration of carefully selected functions, low memory cost, and low control overhead. One main contribution of this work is a study of important issues in programmable baseband processing such as software-hardware partitioning, instruction level acceleration, low power design, and memory issues. Further contributions are a unique optimized instruction set architecture, a unique architecture for efficient integration of hardware accelerators in the processor, and mapping of complete baseband applications to the presented architecture. The architecture has been proven in a manufactured demonstrator chip for wireless LAN applications. Wireless LAN firmware has been developed and run on the chip at full speed. Silicon area and measured power consumption have proven to be similar to that of a non-programmable ASIC solution.
103

Evaluation of Software Defined Radio platform with respect to implementation of 802.15.4 Zigbee

Dabcevic, Kresimir January 2011 (has links)
With the development of powerful computational resources such as Digital Signal Processors and Field Programmable Gate Arrays, It has become possible to utilize many radio functions via software. This is the main concept of an up-and-coming technology of Software Defined Radio. In the Thesis, a number of platforms for implementation of Software Defined Radio has been evaluated. Platform that proved to be most suitable for the project was Ettus’ USRP N210. Using the platform, implementation of 802.15.4 Zigbee’s physical layer was done, where experiments whose outputs can later be used to compare performance with respect to "hardware radios" were performed. / Med utvecklingen av enheter med kraftfulla beräkningsegenskaper som “Digital Signal Processors” och “Field Programmable Gate Arrays” har det blivit möjligt att implementera flera radiofunktioner i mjukvara. Det är huvudkonceptet i den uppåtgående teknologin mjukvaru definierad radio.I det här examensarbetet har ett flertal plattformar för mjukvaru definierad radioutvärderats. Plattformen som visade sig vara mest lämplig för projektet var Ettus USRP N210. En implementation av IEEE 802.15.4 Zigbees fysiska lager har realiserats till plattformen. Experiment, vars utdata senare kan användas för att jämföra prestanda mellan mjukvaru definierad radio och hårdvaru baserad radio, har även utförts. / TESLA - Time-critical and Safe wireLess Automation communication / GAUSS - Guaranteed Automation communication Under Severe disturbanceS
104

Flot de conception système sur puce pour radio logicielle

Tian, Guangye 28 June 2011 (has links) (PDF)
La Radio Logicielle (SDR) est une radio dont les transformations de la forme d'onde, modulation, démodulation des signaux d'un système radio sont mises en œuvre par du logiciel plutôt que par du matériel à fonctionnalité spécifique. Avec cette approche, l'adaptation du système à une autre norme de communication, ou même l'évolution vers une technologie plus récente peuvent être réalisés par mise à jour du logiciel sans remplacement du matériel qui serait long et coûteux. L'architecture de communication logicielle (Software Communication Architecture, SCA), est une architecture ouverte largement acceptée pour les projets de SDR. La spécification SCA minimise le coût de portage des applications en fournissant une couche d'abstraction qui rend transparentes les méthodes spécifiques de chaque système. Dans cette thèse, on s'intéresse au développement et à la programmation d'une plateforme SDR conforme à SCA.Les nouvelles plateformes de SDR sont en général implémentées sur des plateformes multiprocesseurs système sur puce (MPSoC) exploitant ses importantes ressources de calculs avec une bonne efficacité énergique. Les possibilités d'un rapide développement, déploiement et vérification des logiciels embarqués parallèles sur ces nouvelles plateformes MPSoC sont autant de points clés pour satisfaire les objectifs de performance tout en respectant les délais de mise à disposition sur le marché et le coût de développement.On a proposé un flot de conception pour la SDR avec l'exploration architecturale systématique et l'optimisation multi-objective utilisant le modèle de programmation hybride (distribué client/serveur + parallèle).On a étudié aussi la synthèse de topologie de réseau-sur-puce (PSTRP) qui est une partie du flot de conception. Le problème de la synthèse de la topologie du réseau-sur-puce peut se modéliser sous forme de programme linéaire en nombres entiers. Les résultats montrent que les contraintes d'implémentation, comme la hiérarchie du réseau sur puce, doivent être prises en compte pour obtenir un résultat à la fois mathématiquement optimisé et électroniquement réalisable.
105

Optimization of Multi-standards Software Defined Radio Equipments: A Common Operators Approach

Gul, Sufi Tabassum 12 November 2009 (has links) (PDF)
La technique de paramétrisation est très prometteuse pour la conception radio logicielle. La radio logicielle consiste à concevoir des systèmes multi-standards qui tirent bénéfice des possibilités de programmation ou de reconfiguration offertes par les composants de traitement la constituant. Cette thèse étudie la technique de paramétrisation par opérateurs communs. Les opérateurs communs sont des unités de traitements communes à plusieurs opérations qu'effectue un équipement, quelle que soit la couche du modèle OSI à laquelle elles appartiennent. La méthode proposée repose sur une approche théorique afin de résoudre le problème de conception d'un équipement multi-standards. Elle consiste en une optimisation d'un hypergraphe. La conception de l'équipement est représentée par des opérateurs à différents niveaux de granularité dans un graphe acyclique orienté. Le niveau le plus élevé représente une approche de conception d'équipements multi-standards de type Velcro. Plus les opérateurs sont bas dans le graphe, plus leur coût est faible en termes de complexité, mais plus il faut faire appel de fois à eux pour effectuer des opérations de différentes sortes. Nous décrivons ensuite en tant qu'exemples des conception basées sur les opérateurs DMFFT (dual mode FFT), LFSR (linear feedback shift register) et le cas du FRMFB (frequency response masking filter bank). Les solutions basées sur les opérateurs communs proposées dans cette thèse peuvent contribuer à optimiser la conception des futurs équipements multi-standards de radio logicielle qui devront supporter de nombreux standards de communication sans fil.
106

Physical Layer Approach for Securing RFID Systems

Kaleem, Muhammad Khizer January 2013 (has links)
Radio Frequency IDentification (RFID) is a contactless, automatic identification wireless technology primarily used for identifying and tracking of objects, goods and humans. RFID is not only limited to identification and tracking applications. This proliferating wireless technology has been deployed in numerous securities sensitive applications e.g. access control, e-passports, contactless payments, driver license, transport ticking and health cards. RFID inherits all the security and privacy problems that are related to wireless technology and in addition to those that are specific to RFID systems. The security and privacy protection schemes proposed in literature for wireless devices are mostly secured through symmetric/asymmetric keys encryption/decryption and hash functions. The security of all these cryptographic algorithms depends on computationally complex problems that are hard to compute using available resources. However, these algorithms require cryptographic operations on RFID tags which contradict the low cost demand of RFID tags. Due to limited number of logic gates in tags, i.e., 5K-10K, these methods are not practical. Much research effort has done in attempt to solve consumer's privacy and security problem. Solutions that prevent clandestine inventory are mostly application layer techniques. To solve this problem, a new RFID physical layer scheme has been proposed namely Direct Sequence Backscatter Encryption (DSB Enc). The proposed scheme uses level generator to produce different levels before transmitting the signal to the tag. The tag response to the signal sent by the reader using backscatter communications on the same signal which looks random to the eavesdropper. Therefore eavesdropper cannot extract the information from reader to tag and tag to reader communication using passive eavesdropping. As reader knows the different generated levels added to the carrier signal, it can remove the levels and retrieve the tag's messages. We proposed a lightweight, low-cost and practically secure physical layer security to the RFID system, for a supply chain processing application, without increasing the computational power and tag's cost. The proposed scheme was validated by simulations on GNU Radio and experimentation using SDR and a WISP tag. Our implementation and experimental results validate that DSB Enc is secure against passive eavesdropping, replay and relay attacks. It provides better results in the presence of AWGN channel.
107

Antenna Characterization with Autonomous UAV and Software Defined Radio

Wennerholm, Lucas, Alenius, Adam January 2018 (has links)
A measurement equipment with the purpose of measuring the radiation pattern of antennas in the frequency interval 30-300 MHz was constructed. To perform the necessary measurements the equipment needs to be mounted on a UAV, a necessity that demands a low weight from the measurement equipment. These kinds of measurements are today done with equipment that is mounted on helicopters, making the equipment smaller and fitting it on an UAV will save cost for the persons or companies that need to utilize this service. To ensure that the system is easy to use for anyone who wants to characterize an antenna efforts were made to make the software application user friendly. The system visualizes measurement results in 2D diagrams that are simple to analyze. Since the equipment has size restrictions the computer in the system needs to be small and light. The single board computer used has computational limitations and therefore the digital signal processing must be carefully designed to both be fast and generate good measurement data. To verify the performance of the system tests and theoretical simulations where performed and compared. The tests were performed both in an echo free antenna chamber and in realistic outdoor environments with an UAV. The finished system performed well and the measurement results showed clear similarities with the theoretical simulations. The outdoor environment clearly influences the shape of an antennas radiation pattern and the need to characterize antennas in a realistic environment became clear.
108

A caça comercial de jacarés no baixo rio Purus e suas implicações no manejo sustentável na Reserva Piagaçu-Purus, Amazônia Central

Mendonça, Washington Carlos da Silva 09 August 2009 (has links)
Made available in DSpace on 2015-04-11T13:54:35Z (GMT). No. of bitstreams: 1 Dissertacao Washington Carlos da Silva Mendonca.pdf: 484370 bytes, checksum: a48adf077b33b55e5d78ab164b39391d (MD5) Previous issue date: 2009-08-09 / Fundação de Amparo à Pesquisa do Estado do Amazonas / This study valuated the caimans hunting with hook practiced in the Low Purus river at the Sustainable Development Reserve (RDS) Piagaçu-Purus, Central Amazon. This activity is realized by the riveriner aim the caiman meat production in salt-dry to supply the interstates trade. The knowledge scenery about the hunting of caiman with hook was put in public since 2003, however, not much is know about this catch effects on the caiman hunting productivity and its catch length. Aim to valuate the effect of this catch, were accompanied 31 caiman hunting with hook in the period of February to October 2008. Multiple Linear Regressions and Simple Linear Regression Analyzes were applied to model the caiman catch production and size. The mass of meat produced by the hunting were modeling in function of the river water level, community distance and hunting effort using hook. Were caught 124 caimans, where: 53 with suspense hook and 71 with the hook armed under land. The modeling of the size of hook and to water deep explained 48% of caiman length variance, while the modeling that used the height of hook parameter above the water surface and water deep explain 38% of this variance. The Simple Linear Regression was utilized to modeling the caiman length caught in function of distance hook traped under land from the interface water-land, showing a variance of 60% for the sample size. The hunting effect presented in this study indicates the intensive hunting pressure on the caiman population, confirmed through produced caiman meat decreasing near to hunters communities. Confirmed through Multiple Linear Regression values expressed for 70% of variance for this production. Was observed too that the caiman hunting are proportionally inverse to the river water level. The Caiman crocodilus caught length present higher abundance of individual above 70cm of snout-vent length. This indicate that the hunting method guard the replacement individuals to maintain the caiman population. While the Melanosuchus niger specie had the higher abundance of caught individual sub adult, noting the reduction of big adults. The absence of this caiman length class sustain the hypothesis that the individual lenght structure of M. niger population are probably affected by the intense hunting pressure. The results presented can be utilized to subsides the public policy for assert the sustainable management of caiman in the Amazon States, Brazil. / Este estudo avaliou a caça de jacaré com anzol praticada no baixo Rio Purus na Reserva de Desenvolvimento Sustentável (RDS) Piagaçu-Purus, Amazônia Central. Esta atividade é realizada pelos ribeirinhos e visa à produção de carne de jacaré seco-salgada para abastecer o comércio interestadual. O conhecimento do cenário sobre a caça de jacaré com anzol foi levado a publico em 2003, no entanto, pouco se sabe sobre os efeitos desta caça quanto à sua produtividade e tamanho de captura. Com intuito de avaliar o efeito desta prática, foram acompanhadas 31 caçadas de jacaré com anzol no Período de fevereiro a outubro de 2008. Análises de Regressão Linear Múltipla e Simples foram aplicadas para modelar a produção e tamanho dos jacarés capturados. A quantidade de carne produzida por caçada foi modelada em função da cota do rio, da distância da comunidade e do esforço de caça com anzol. Foram capturados 124 jacarés, onde: 53 com anzol suspenso e 71 com anzol armado sobre o solo. A modelagem do tamanho do anzol e da profundidade da água explicou 48% da variância dos tamanhos dos jacarés, enquanto que o modelo que utilizou os parâmetros da altura do anzol acima da lâmina de água e profundidade da água explicou 38% dessa variância. A Regressão Linear Simples foi utilizada para modelar o tamanho do jacaré capturado em função da distância do anzol armadilhado em terra até a interface água-terra, mostrando uma variância de 60% no tamanho dos exemplares. Os efeitos da caça de jacaré apontados neste estudo indicam intensa pressão de caça sobre o estoque, confirmado através da diminuição de carne produzida próximo as comunidades ali instaladas. Confirmado através dos valores da Regressão Linear Múltipla que expressou 70% de variância nessa produção. Foi observado também, que a captura do jacaré é inversamente proporcional ao nível do rio. Os tamanhos dos Caiman crocodilus capturados apresentaram maior abundância de indivíduos acima de 70 cm de comprimento rostro-cloacal indicando que o método de caça resguarda indivíduos repositores para a manutenção da população. Enquanto que a espécie Melanosuchus niger, teve a maior abundância de indivíduos capturados subadultos, notando-se baixa de grandes adultos. A ausência desta classe de tamanho sustenta a hipótese de que a estrutura de tamanho dos indivíduos na população de M. niger é provavelmente afetada pela intensa pressão de caça. Os resultados apresentados podem ser utilizados para subsidiar políticas publicas que possam assegurar o manejo sustentável do jacaré no Estado do Amazonas.
109

Implementação de técnicas robustas de codificação e modulação para o sistema ISDB-TB LDM

Oliveira, George Henrique Maranhão Garcia de 06 February 2017 (has links)
Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-02-08T20:32:01Z No. of bitstreams: 2 GEORGE HENRIQUE MARANHÃO GARCIA DE OLIVEIRA.pdf: 3162275 bytes, checksum: 7e4e2ff4fcb19dbee94fa8f9ac1a5a69 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-04-03T15:10:51Z (GMT) No. of bitstreams: 2 GEORGE HENRIQUE MARANHÃO GARCIA DE OLIVEIRA.pdf: 3162275 bytes, checksum: 7e4e2ff4fcb19dbee94fa8f9ac1a5a69 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-03T15:10:51Z (GMT). No. of bitstreams: 2 GEORGE HENRIQUE MARANHÃO GARCIA DE OLIVEIRA.pdf: 3162275 bytes, checksum: 7e4e2ff4fcb19dbee94fa8f9ac1a5a69 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-06 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundo Mackenzie de Pesquisa / This work presents the characteristics of the ISDB-TB, adopted in Brazil as part of Digital TV Brazilian System (SBTVD) and the challenges and needed adaptations for the next digital TV generations. It also shows the historic of SDR, physical layer LDM, NUC modulations and error correction code LDPC technologies. Their advantages are demonstrated in terms of eficient use of spectrum, robustness and increase of transmission rate. A digital communication system with this technologies was proposed, allowing the compatibility with the ISDB-TB system. The focus of this work are the stages of coding and modulation in the LDM lower layer, enabling better performance of this technique in the ISDB-TB system. This implementation was performed with the software GNU Radio Companion and the use of the C ++ language. / Este trabalho apresenta as características do ISDB-TB, adotado no Brasil como parte do Sistema Brasileiro de TV Digital (SBTVD) e os desafios e adaptações necessárias para as próximas gerações da TV digital. O trabalho também mostra o histórico das tecnologias SDR, camada física LDM, modulações NUC e código corretor de erro LDPC. Suas vantagens de utilização são demonstradas em termos de sua eficiência espectral, robustez e do aumento da taxa de dados transmitida. Um sistema de comunicação digital unindo estas tecnologias é proposto, permitindo a compatibilidade com o sistema ISDB-TB. O foco deste trabalho são as etapas de codificação e modulação da camada inferior do LDM, permitindo maior desempenho desta técnica no sistema ISDB-TB. Esta implementação foi realizada com o software GNU Radio Companion e o uso da linguagem C++.
110

Modelování a simulace příjímače komunikačního systému pro bezpilotní letadla / Modelling and simulation of communication system receiver for unmanned aircraft

Hoferek, Jakub January 2018 (has links)
This diploma thesis deals with the simulation of the radio communication system for satellite control of unmanned aircraft, namely the command and control communication link – the forward link. The aim of the thesis is to create a simulator in the Matlab environment. The simulator includes a model of the transmitter, radio channel and receiver. Four-state CPM modulation with partial response and filtered symbol shape is used. The radio channel performs noise, frequency Doppler shift and time delay to the received signal. Subsequently, in the Acquisition Unit, the Doppler shift and time delay are detected and compensated. At the end of the thesis, the simulation results of the presented model are presented in the form of graphs đť¸s/đť‘0.

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