Com o aumento das aplicações e dispositivos para Internet das Coisas, muitos esforços para reduzir potência dissipada nos transceptores foram investidos. A maioria deles, entretanto, focam individualmente no rádio, nos conversores analógicos para digital e viceversa, e na arquitetura de banda base digital. Como consequência, há pouca margem para melhorias na potência dissipada nestes blocos isolados que compense o enorme esforço. Portanto, este trabalho propõe uma arquitetura adaptativa a nível de sistema focando em reduzir o consumo no conversor analógico para digital e no receptor digital. Ele utiliza um algoritmo robusto para o receptor banda base digital, um conversor analógico para digital topologia Sigma-Delta e um bloco de controle realimentado conforme a relação sinal ruído medida do pacote recebido. O sistema foi projetado para o protocolo IEEE 802.15.4. Para validação do sistema e estimar a potência consumida foi feito um modelo de sistema utilizando a ferramenta Matlab, uma descrição do hardware em linguagem Verilog e uma síntese lógica utilizando o processo da X-FAB XC018. As simulações mostram uma redução na potência consumida pelo sistema de até 13% e ainda atingindo os requisitos do protocolo. Os resultados deste trabalho foram publicados na conferência internacional em tecnologia de instrumentação e medidas de 2014 realizada na cidade de Montevidéu no Uruguai. / With the increase of Internet of Things applications and devices, many efforts to reduce power consumption in transceiver has been invested. Most of them targeted in RF frontend, converters, or in the digital baseband architecture individually. As result, there are few margins nowadays for power improvement in these blocks singly that compensates the huge hard work required. The next optimization step leads to a system level analysis seeking design space and new possibilities expansion. It is in this field that adaptive systems approaches are conquering ground recently. The solutions combines Radio Frequency (RF) and process variation techniques, Low Pass Filters (LPF) and Analog to Digital Converters (ADCs) adjustment for better performance, digital baseband bit width adaptive according to income packet SNR, configurable ADC resolution and topology, and others. In this scenario the current work proposes an adaptive system level architecture targeting ADC and digital receiver power reduction. It uses a robust algorithm for digital baseband receiver, a Sigma-Delta ADC, and suggests a feedback control block based on packet SNR measure. The system was designed for the IEEE 802.15.4 standard and required system modeling using Matlab tool, hardware description in Verilog language, and logic synthesis using X-FAB XC018 process for validation and power consumption estimation. Simulations show up to 15% of system power reduction and still meeting the standard requirements. The work results were published in the International Instrumentation and Measurement Technology Conference of 2014 occurred in Montevideo - Uruguay.

The mobile wireless communication systems has been growing fast and continuously over the past two decades. Therefore, in order to fulfill the demand for this rapid growth, the standardization bodies along with wireless researchers and mobile operators around the world have been constantly working on new technical specifications.An important problem in modern communication is known as NP complete problem in the Maximum Likelihood (ML) detection of signals transmitting over Multiple Input Multiple Output channel of the OFDM transceiver system. Development of the Sphere Decoder (SD) as a result of the rapid advancement in signal processing techniques provides ML detection for MIMO channels at polynomial time complexity average case. There are weaknesses in the existing SDs. The sphere decoder performance is very sensitive for the most current proposals in order to choose the search radius parameter. At high spectral efficiencies SNR is low or as the problem dimension is high and the complexity coefficient can become very large too. Digital communications of detecting a vector of symbols has importance as, is encountered in several different applications. These symbols are as the finite alphabet and transmitted over a multiple-input multiple-output (MIMO) channel with Gaussian noise. There are no limitation to the detection of symbols spatially multiplexed over a multiple-antenna channel and the multi user detection problem. Efficient algorithms are considered for the detection problems and have recognized well. The algorithm of sphere decoder, orders has optimal performance considering the error probability and this has proved extremely efficient in terms of computational complexity for moderately sized problems in case of signal to noise ratio. At high SNR the algorithm has a polynomial average complexity and it is understood the algorithm has an exponential worst case complexity. The efficiency of the algorithm is ordered the exponential rate derivation of growth. Complexity is positive for the finite SNR and small in the high SNR. To achieve the sphere decoding solution applying Schnorr-Euchner by Maximum likelihood method , Depth-first Stack-based Sequential decoding is used. This thesis focuses on the receiver part of the transceiver system and takes a good look at the near optimal algorithm for sphere detection of a vector of symbols transmitted over MIMO channel. The analysis and algorithms are general in nature. / Cell:+8801553448014

The evolved version of LTE is LTE-Advanced which is being developed by 3GPP. LTE-Advanced will meet or go beyond the requirements of the International Telecommunication Union (ITU) for the fourth generation (4G) radio communication standard known as IMT-Advanced. LTEAdvanced is primarily considered as a part of Release 10 of 3GPP specifications. The LTE-Advanced specifications will continue to be developed in subsequent 3GPP releases. The complete physical layer structure has been employed by using the latest 3GPP standards. Furthermore, technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) have also been implemented and integrated with LTEAdvanced. The Multiple Access Scheme in Advanced Mobile radio system has to meet the specific requirements such as: high throughput, robustness, efficient Bit Error Rate (BER), high spectral efficiency, minimum delays, low computational complexity, low Peak to Average Power Ratio (PAPR), low error probability etc. In order to investigate the LTE-Advanced transceiver a thorough study has been carried out using MATLAB Simulink using AWGN and Rayleigh fading channel. This report investigates the performance of OFDMA and various MIMO configurations of LTEAdvanced physical layer, along with diverse modulation techniques such 16QAM and QPSK,the results are then demonstrated on BER and signal to noise ratio graphs. AWGN and Rayleigh fading models are also used to determine the performance of LTE-Advanced in presence of noise and fading.

This diploma thesis is focused on several ways of communication among people involved in alavanche accident. Different ways of communication are compared. Diploma is focused on verification of features and parameters of avalanche transceivers. Basic introduction in the field of usage of these devices is included. Practical measurement in high-altitude winter mountain terrain and measurement in laboratory verify parameters provided by producers of avalanche transceivers. Different models of avalanche transceivers will be compared. Behaviour of devices will be modeled on computer. Based on simulation results and other findings wiring of receiving and transmitting par of avalanche transceiver will be designed.

This thesis deals with the design and the realization of the radiocommunication monitor for the 868 MHz band. In the thesis, a description of licence-free radio bands complying ITU recommendations and ETSI standards is given. A special attention is paid to the 863 MHz - 870 MHz band. The transceiver CC1020 that forms the base for the monitor is described in detail. The circuit design, the monitor assembly and the firmware creation are presented step by step. The radiocommunication monitor is portable and battery powered. The monitor is able to display RF signals in the 868 MHz band, to indicate the frequency error of the transmitter and to receive FSK modulated signal. Demodulated data can be transferred to the personal computer via the USB.

This thesis deals with a design and implementation monitoring system of Starhill society computer network. Part of the design is development and realization hardware modules that provide restarting of remote network devices. Command transmission is realized through discretionary transceivers available, whose regulations can make such transmissions possible. A usage of 466~MHz frequency band is the main assumption. Both concept and implementation are described in the thesis. The designed system is integrated to the existing IS of the association.

Ce projet doctoral s’est déroulé dans le cadre d’une collaboration entre le laboratoire d’Imagerie par Résonance Magnétique Médicale et Multi-Modalités (IR4M) de l’Université Paris-Sud (France) et le Center for Medical Physics and Biomedical Engineering at Medical (CMPBME) de l’Université Médicale de Vienne (Autriche). L’objectif principal de ce travail était de développer un réseau d’antennes radiofréquence flexible fonctionnant en émission/réception pour l’IRM à 7T. Les réseaux d’antennes permettent de bénéficier du rapport signal sur bruit élevé des antennes de surface de petites tailles tout en accédant à un champ de vue étendu. De plus, les réseaux d’antennes permettent l’utilisation de technique d’imagerie parallèle afin d’accélérer l’acquisition des images ainsi que l’utilisation d’algorithme de transmission parallèle afin de produire un champ radiofréquence homogène, ce qui est crucial en IRM. Ce projet doctoral visait la conception, le développement, l’installation et l’évaluation d’un réseau d’antenne RF flexible basé sur le principe des résonateurs à lignes de transmission (RLT). Ces structures sont intrinsèquement monolithiques et auto-résonantes et ne nécessitent donc pas l’emploi de condensateurs discrets pour accorder l’antenne. Des simulations électromagnétiques 3D, ainsi que des caractérisations expérimentales sur table et en IRM ont été réalisées pour évaluer les performances de ce réseau, en configuration plate et courbée. / This PhD thesis was conducted in the frame of a bilateral project between the laboratoire d’Imagerie par Résonance Magnétique Médicale et Multi-Modalités (IR4M) at Université Paris-Sud (Orsay, France) and the Center for Medical Physics and Biomedical Engineering (CMPBME) at the Medical University of Vienna (Vienna, Austria). The main objective of this work was to develop a flexible transceiver RF coil array for 7 T MRI. Coil arrays benefit from the high SNR of small surface coils over an extended field of view (FOV). Furthermore, array coils enable the use of parallel imaging (PI) techniques for accelerated image acquisition and pTx algorithms that can be used to produce a homogeneous transmit field which is of importance in MRI. This project targets the design, development, implementation and evaluation of a flexible RF coil array based on the transmission line resonator (TLR) principle. TLRs are inherently monolithic and self-resonant structures, i.e. there is no need for lumped element capacitors to tune the coil. 3D electromagnetic simulation (EMS) together with bench and MRI experiments were performed to evaluate the performance of the developed array in flat and bent configuration.

The scope of this work is the development of a 60 GHz flexible transceiver frontend by adopting an economic prototyping approach. Such a platform can validate the proposed protocols for the 60 GHz band in a real wireless environment, especially the physical layer security concept. The development course uses the hybrid architecture with off-the-shelf components and custom-designed RF chain blocks on printed circuit technology. Challenge in this approach is the coarse resolution of the selected manufacturing technology and higher process tolerance. This work extends the state-of-the-art by proposing etching-resilient RF chain blocks on wide bandwidths. It presents the design validation of each block and performance analysis for various manufacturing conditions. The study also reviews and proposes a high-frequency interconnect model for bondwires, vital in a frontend design. Parasitics' compensation of the interconnects at millimeter-wave operation is proposed, compatible with printed circuit technology. The 60 GHz frontend is realized by packaging the designed RF blocks and off-the-shelf components with optimized and characterized high-frequency interconnects. The frontend, equipped with a tailor-made antenna duplexer, is reconfigurable for frequency, power, and modulation scheme. The developed frontend is characterized for local oscillator, transmitter, and receiver operations. The adaptability of the frontend allows it to be used as an agent in a heterogeneous network. Two units of the developed frontends are used in a network for frequency domain channel sounding. The antenna duplexer ensures channel reciprocity in bidirectional sounding campaigns. Matched two-way channel response is achieved in various indoor environments, which endorses the frontend for channel reciprocity key generation. Finally, the frontend units are successfully deployed in a physical layer security demonstrator.:Abstract Chapter1: Introduction Chapter 2: Fundamentals and state-of-the-art Chapter 3: The design Chapter 4: Integration and characterization Chapter 5: Application example: Channel sounder Chapter 6: Summary and future work Appendices Bibliography

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