IR-UWB and OFDM-UWB Transceiver Nodes for Communication and Positioning Purposes

Résumé Ultra-wideband (UWB) a suscité l'intérêt de chercheurs et de l'industrie en raison de ses nombreux avantages tels que la faible probabilité d'interception et de la possibilité de combiner la communication des données de positionnement dans un seul système. Il existe plusieurs UWB couche physique (PHY) présentées initialement à la norme IEEE qui convergent en deux propositions principales: des porte-UWB ou Orthogonal Frequency-Division Multiplexing (OFDM-UWB), et à court d'impulsion porteuse à-UWB ou Impulse Radio-(IR-UWB). Une des plus grandes tâches difficiles pour les chercheurs est de nos jours la conception d'émetteurs-récepteurs UWB optimisés qui satisfont à des conditions rigoureuses, dont la simplicité caractéristiques large bande, à faible coût et de conception. Des études antérieures ont montré que les récepteurs à conversion directe basée sur Wave-radio interféromètre (WRI) circuits représentent un bon candidat pour les applications UWB. Circuits IRG ont plusieurs avantages tels que l'exploitation à large bande, à faible coût et la simplicité. Des travaux antérieurs sur l'IRG circuit, cependant, a enquêté sur le circuit de l'IRG sur la base du concept de porteuse unique signaux (par exemple, les signaux sinusoïdaux). L'objectif de ce projet est de fournir les résultats de conception, de simulation, de mise en oeuvre et le test d'un émetteur-récepteur WRI basé sur ce que peut être utilisé comme un noeud ou un pico-réseau dans un détecteur sans fil / réseau de données. Nous allons passer par les étapes de conception et de mise en oeuvre de propositions UWB deux: IR-UWB et OFDM-UWB. Pour la proposition porteuse à nous concentrer sur la conception et la mise en oeuvre de l'émetteur-récepteur en intégrant les opérations de transmission / réception dans un prototype unique, alors que pour la proposition des porte-nous concevoir et mettre en oeuvre l'émetteur-récepteur avec le circuit de l'IRG dans le récepteur seulement utilisé en tant que convertisseur abaisseur directe. Résultats expérimentaux, de simulation et d'analyse ont été obtenus et sont présentés dans cette thèse.----------Abstract Ultra-wideband (UWB) technology has attracted interest from both researchers and the industry due to its numerous advantages such as low probability of interception and the possibility of combining data communication with positioning in a single system. There are several different UWB physical layer (PHY) proposals originally submitted to IEEE which converged into two main proposals: carrier‐based UWB or Orthogonal-Frequency Division Multiplexing (OFDM‐UWB), and short‐pulse carrierless‐UWB or Impulse-Radio (IR-UWB). One of the biggest challenging tasks for researchers nowadays is the design of optimized UWB transceivers that would satisfy rigorous conditions, among which wideband characteristics, low-cost and design simplicity. Previous studies have shown that direct-conversion receivers based on Wave-Radio Interferometer (WRI) circuits represent a suitable candidate for UWB applications. WRI circuits have several advantages such as wideband operation, low cost, and simplicity. Previous works on WRI circuit, however, investigated the WRI circuit based on the concept of single-carrier signals (i.e., sinusoidal signals). The objective of this project is to provide the design, simulation, implementation and testing results of a WRI-based transceiver that can be utilized as a node or a piconet in a wireless sensor/data network. We will go through the design and implementation steps for both UWB proposals: IR-UWB and OFDM-UWB. For the carrierless proposal we will focus on designing and implementing the transceiver by integrating the transmitter/receiver operations in a single prototype, while for the carrier‐based proposal we will design and implement the transceiver with the WRI circuit in the receiver only utilized as a direct downconverter

Architectures and Algorithms for the Signal Processing of Advanced MIMO Radar Systems

This thesis focuses on the research, development and implementation of novel concepts, architectures, demonstrator systems and algorithms for the signal processing of advanced Multiple Input Multiple Output (MIMO) radar systems. The key concept is to address compact system, which have high resolutions and are able to perform a fast radar signal processing, three-dimensional (3D), and four-dimensional (4D) beamforming for radar image generation and target estimation. The idea is to obtain a complete sensing of range, Azimuth and elevation (additionally Doppler as the fourth dimension) from the targets in the radar captures. The radar technology investigated, aims at addressing sev- eral civil and military applications, such as surveillance and detection of targets, both air and ground based, and situational awareness, both in cars and in flying platforms, from helicopters, to Unmanned Aerial Vehicles (UAV) and air-taxis. Several major topics have been targeted. The development of complete systems and innovative FPGA, ARM and software based digital architectures for 3D imaging MIMO radars, which operate in both Time Division Multiplexing (TDM) and Frequency Divi- sion Multiplexing (FDM) modes, with Frequency Modulated Continuous Wave (FMCW) and Orthogonal Frequency Division Multiplexing (OFDM) signals, respectively. The de- velopment of real-time radar signal processing, beamforming and Direction-Of-Arrival (DOA) algorithms for target detection, with particular focus on FFT based, hardware implementable techniques. The study and implementation of advanced system concepts, parametrisation and simulation of next generation real-time digital radars (e.g. OFDM based). The design and development of novel constant envelope orthogonal waveforms for real-time 3D OFDM MIMO radar systems. The MIMO architectures presented in this thesis are a collection of system concepts, de- sign and simulations, as well as complete radar demonstrators systems, with indoor and outdoor measurements. Several of the results shown, come in the form of radar images which have been captured in field-test, in different scenarios, which aid in showing the proper functionality of the systems. The research activities for this thesis, have been carried out on the premises of Air- bus, based in Munich (Germany), as part of a Ph.D. candidate joint program between Airbus and the Polytechnic Department of Engineering and Architecture (Dipartimento Politecnico di Ingegneria e Architettura), of the University of Udine, based in Udine (Italy).Questa tesi si concentra sulla ricerca, lo sviluppo e l\u2019implementazione di nuovi concetti, architetture, sistemi dimostrativi e algoritmi per l\u2019elaborazione dei segnali in sistemi radar avanzati, basati su tecnologia Multiple Input Multiple Output (MIMO). Il con- cetto chiave `e quello di ottenere sistemi compatti, dalle elevate risoluzioni e in grado di eseguire un\u2019elaborazione del segnale radar veloce, un beam-forming tri-dimensionale (3D) e quadri-dimensionale (4D) per la generazione di immagini radar e la stima delle informazioni dei bersagli, detti target. L\u2019idea `e di ottenere una stima completa, che includa la distanza, l\u2019Azimuth e l\u2019elevazione (addizionalmente Doppler come quarta di- mensione) dai target nelle acquisizioni radar. La tecnologia radar indagata ha lo scopo di affrontare diverse applicazioni civili e militari, come la sorveglianza e la rilevazione di targets, sia a livello aereo che a terra, e la consapevolezza situazionale, sia nelle auto che nelle piattaforme di volo, dagli elicotteri, ai Unmanned Aerial Vehicels (UAV) e taxi volanti (air-taxis). Le tematiche affrontante sono molte. Lo sviluppo di sistemi completi e di architetture digitali innovative, basate su tecnologia FPGA, ARM e software, per radar 3D MIMO, che operano in modalit`a Multiplexing Time Division Multiplexing (TDM) e Multiplexing Frequency Diversion (FDM), con segnali di tipo FMCW (Frequency Modulated Contin- uous Wave) e Orthogonal Frequency Division Multiplexing (OFDM), rispettivamente. Lo sviluppo di tecniche di elaborazione del segnale radar in tempo reale, algoritmi di beam-forming e di stima della direzione di arrivo, Direction-Of-Arrival (DOA), dei seg- nali radar, per il rilevamento dei target, con particolare attenzione a processi basati su trasformate di Fourier (FFT). Lo studio e l\u2019implementazione di concetti di sistema avan- zati, parametrizzazione e simulazione di radar digitali di prossima generazione, capaci di operare in tempo reale (ad esempio basati su architetture OFDM). Progettazione e sviluppo di nuove forme d\u2019onda ortogonali ad inviluppo costante per sistemi radar 3D di tipo OFDM MIMO, operanti in tempo reale. Le attivit`a di ricerca di questa tesi sono state svolte presso la compagnia Airbus, con sede a Monaco di Baviera (Germania), nell\u2019ambito di un programma di dottorato, svoltosi in maniera congiunta tra Airbus ed il Dipartimento Politecnico di Ingegneria e Architettura dell\u2019Universit`a di Udine, con sede a Udine

Ultra-Wideband Pulse Doppler Radar for Short-Range Targets

This thesis addresses the design and characterization of a pulse Doppler radar designed to detect targets at short range (R ≤ 7m). To minimize the shortest detectable range, a subnanosecond transmitted pulsewidth is desired. UWB design techniques were combined with a pulse Doppler radar architecture to demonstrate a full radar, including the transmitter, receiver, simulated channel, and post processor. The transmitted pulse train has a 2.5GHz carrier frequency, a 730 ps pulsewidth, and a 1GHz 10 dB-bandwidth. The PRF of the radar is 20 MHz, which allows unambiguous range and Doppler detection with a single PRF. The peak transmitted power is 1.2W. The characteristics of the transmitted waveform provide fine range accuracy (δR = ±0.03m), facilitate a short minimum range, and allow for an efficient transmitter design. The receiver was designed to complement the transmitter; it has a homodyne architecture and is pulsed to isolate a specific detectable range. A closed-loop channel model was designed to simulate the range delay, Doppler shift, and channel attenuation of a moving target; the model is connected to the transmitter and receiver with coaxial cable, facilitating bench-top characterization of the radar and eliminating some effects of wireless transmission, such as multipath. Extensive closed-loop radar testing was performed, and the following radar characteristics were determined: (1) The minimum detectable SNR, assuming a 36.5 μs integration time, is 0 dB. (2) Assuming a transmitter-to-receiver isolation of 80 dB, the minimum range of the radar is R[sub]min = 1:3m+R[sub]lk, where R[sub]lk is the apparent leakage range between the transmitter and receiver. Depending on the antenna system design, the radar can detect targets from 1:5m ≤ R ≤ 7m, meeting the original goal of this work. These results support the supposition that a UWB pulse Doppler radar architecture can be employed for short-range, moving target detection

Analysis and Design of Joint Communication and Sensing for Wireless Cellular Networks

Joint communication and sensing (JCAS) has emerged as an important piece of technology that will radically change ordinary wireless communication and radar systems. This research area, which has significantly grown over the last decade, aims to develop integrated systems that can provide both communication and sensing/radar functionalities simultaneously. The convergence of both systems into the same joint platform facilitates a more efficient use of the hardware and spectrum resources, enabling new civilian and professional applications. This thesis focuses on the integration of JCAS functionalities into mobile cellular networks, such as fifth-generation new radio (5G NR) and sixth generation (6G) communication systems, which are developing toward higher frequency ranges at millimeter-wave (mm-wave) bands, coming with wider bandwidths, and have massive antenna arrays, providing a great framework to develop sensing functionalities. By implementing JCAS, the different nodes of the cellular network, such as the base station and user equipment, can sense and reconstruct their surroundings. However, the JCAS operation yields multiple design challenges that need to be addressed. To this end, this thesis aims to develop novel algorithms in two relevant research areas that comprise self-interference (SI) cancellation and beamforming optimization techniques for JCAS systems. This work analyzes the potential sensing performance of mobile cellular networks, proposing a joint framework and identifying the main radar processing techniques to support JCAS. The fundamental SI challenge stemming from the simultaneous operation of the transmitter and receiver is investigated, and different JCAS cancellation techniques are proposed. The performance and feasibility of the proposed JCAS system is evaluated through simulation and measurement experiments at different frequency bands and scenarios, identifying mm-wave frequencies as the key enabler for future JCAS systems. Alternative antenna architectures and beamforming methods for mm-wave JCAS platforms are proposed by considering both communication and sensing requirements. Specifically, this thesis proposes novel beamforming methods that provide multiple beams, supporting efficient beamformed communications while an additional beam senses the environment simultaneously. In addition, the proposed beam-forming algorithms address the SI challenge by implementing an efficient spatial suppression scheme to suppress the direct transmitter–receiver coupling

The Design of a Novel Tip Enhanced Near-field Scanning Probe Microscope for Ultra-High Resolution Optical Imaging

Traditional light microscopy suffers from the diffraction limit, which limits the spatial resolution to λ/2. The current trend in optical microscopy is the development of techniques to bypass the diffraction limit. Resolutions below 40 nm will make it possible to probe biological systems by imaging the interactions between single molecules and cell membranes. These resolutions will allow for the development of improved drug delivery mechanisms by increasing our understanding of how chemical communication within a cell occurs. The materials sciences would also benefit from these high resolutions. Nanomaterials can be analyzed with Raman spectroscopy for molecular and atomic bond information, or with fluorescence response to determine bulk optical properties with tens of nanometer resolution. Near-field optical microscopy is one of the current techniques, which allows for imaging at resolutions beyond the diffraction limit. Using a combination of a shear force microscope (SFM) and an inverted optical microscope, spectroscopic resolutions below 20 nm have been demonstrated. One technique, in particular, has been named tip enhanced near-field optical microscopy (TENOM). The key to this technique is the use of solid metal probes, which are illuminated in the far field by the excitation wavelength of interest. These probes are custom-designed using finite difference time domain (FDTD) modeling techniques, then fabricated with the use of a focused ion beam (FIB) microscope. The measure of the quality of probe design is based directly on the field enhancement obtainable. The greater the field enhancement of the probe, the more the ratio of near-field to far-field background contribution will increase. The elimination of the far-field signal by a decrease of illumination power will provide the best signal-to-noise ratio in the near-field images. Furthermore, a design that facilitates the delocalization of the near-field imaging from the far-field will be beneficial. Developed is a novel microscope design that employs two-photon non-linear excitation to allow the imaging of the fluorescence from almost any visible fluorophore at resolutions below 30 nm without changing filters or excitation wavelength. The ability of the microscope to image samples at atmospheric pressure, room temperature, and in solution makes it a very promising tool for the biological and materials science communities. The microscope demonstrates the ability to image topographical, optical, and electronic state information for single-molecule identification. A single computer, simple custom control circuits, field programmable gate array (FPGA) data acquisition, and a simplified custom optical system controls the microscope are thoroughly outlined and documented. This versatility enables the end user to custom-design experiments from confocal far-field single molecule imaging to high resolution scanning probe microscopy imaging. Presented are the current capabilities of the microscope, most importantly, high-resolution near-field images of J-aggregates with PIC dye. Single molecules of Rhodamine 6G dye and quantum dots imaged in the far-field are presented to demonstrate the sensitivity of the microscope. A comparison is made with the use of a mode-locked 50 fs pulsed laser source verses a continuous wave laser source on single molecules and J-aggregates in the near-field and far-field. Integration of an intensified CCD camera with a high-resolution monochromator allows for spectral information about the sample. The system will be disseminated as an open system design

Acoustic and Elastic Waves: Recent Trends in Science and Engineering

The present Special Issue intends to explore new directions in the field of acoustics and ultrasonics. The interest includes, but is not limited to, the use of acoustic technology for condition monitoring of materials and structures. Topics of interest (among others): • Acoustic emission in materials and structures (without material limitation) • Innovative cases of ultrasonic inspection • Wave dispersion and waveguides • Monitoring of innovative materials • Seismic waves • Vibrations, damping and noise control • Combination of mechanical wave techniques with other types for structural health monitoring purposes. Experimental and numerical studies are welcome

Self-Heating Aware Design of ICs in Deep Sub-Micron FDSOI and Bulk Technologies

Bulk CMOS technologies left the semiconductor market to the novel device geometries such as FDSOI and FinFET below 30 nm, mainly due to their insufficient electrical characteristics arising from different physical limitations. These innovative solutions enabled the ongoing device scaling to continue. However, the threshold voltage and the power supply values did not shrink with the device sizes, which caused an excessive amount of heat generation in very small dimensions. With the high thermal resistivity materials used in FDSOI and FinFET, the generated heat cannot leave the device easily, which is not the case in bulk. With all of these, modern geometries brought a major problem, which is the self-heating. Due to self-heating effects (SHE), the temperature of a device rises significantly compared to its surroundings. Having very large local temperature brings important reliability issues. Moreover, the electrical behaviour of a device also changes dramatically when its temperature is very large. These facts bring the need of considering SHE and the temperature of each device separately. Nevertheless, in many of today's CAD tools, a single global temperature is applied to all of the devices. Even if some advanced simulation options are used, estimating the temperature of a device is not a simple task as it depends on many parameters. The focus of this thesis is to show the significance of SHE in the design of ICs and provide self-heating aware design guidelines. In order to achieve this, different circuit implementations are studied by considering the SHE. The study consists of two main parts, which are the reliability of the high-speed digital circuits and the performance of analog blocks where noise is critical. Moreover, detailed device-level electro-thermal simulations are performed to explain the self-heating phenomena more in detail and to perform a comparison between bulk and FDSOI. The digital part of the self-heating study is performed on two very high-speed full-custom 64-bit Kogge-Stone adders in 40 nm and 28 nm technologies. Thermal simulations are performed on these blocks to compare SHE in bulk and FDSOI geometries. The comparison of two implementations also provides the increasing significance of SHE with scaling. Extensive heating analyses are performed to find the most critical devices that are the primary heat generators. Design guidelines and solutions are proposed to flatten the temperature profiles in precharged and static logic implementations and to decrease the probability of electromigration. The analog study of the work focuses on the thermal noise performance of LNAs and SHE on the flicker noise. Since thermal noise of a device linearly depends on the temperature, it is directly affected by SHE. To show the amount of SHE on the noise figure, three common gate cascode LNAs operating at 2 GHz with different device lengths are implemented in 28 nm FDSOI. The measurements show that the self-heating effects are clearly observed on the noise figure and the performance of the blocks deviate importantly from the simulations. Moreover, the self-heating effects are significantly more in short channel devices due to their large heat density. Similar experiments are also performed on different test structures in FDSOI at lower frequencies to observe SHE on flicker noise. The experiments show that flicker noise degrades at larger temperatures and more in short channel implementations

Signal processing architectures for automotive high-resolution MIMO radar systems

To date, the digital signal processing for an automotive radar sensor has been handled in an efficient way by general purpose signal processors and microcontrollers. However, increasing resolution requirements for automated driving on the one hand, as well as rapidly growing numbers of manufactured sensors on the other hand, can provoke a paradigm change in the near future. The design and development of highly specialized hardware accelerators could become a viable option - at least for the most demanding processing steps with data rates of several gigabits per second. In this work, application-specific signal processing architectures for future high-resolution multiple-input and multiple-output (MIMO) radar sensors are designed, implemented, investigated and optimized. A focus is set on real-time performance such that even sophisticated algorithms can be computed sufficiently fast. The full processing chain from the received baseband signals to a list of detections is considered, comprising three major steps: Spectrum analysis, target detection and direction of arrival estimation. The developed architectures are further implemented on a field-programmable gate array (FPGA) and important measurements like resource consumption, power dissipation or data throughput are evaluated and compared with other examples from literature. A substantial dataset, based on more than 3600 different parametrizations and variants, has been established with the help of a model-based design space exploration and is provided as part of this work. Finally, an experimental radar sensor has been built and is used under real-world conditions to verify the effectiveness of the proposed signal processing architectures.Bisher wurde die digitale Signalverarbeitung für automobile Radarsensoren auf eine effiziente Art und Weise von universell verwendbaren Mikroprozessoren bewältigt. Jedoch können steigende Anforderungen an das Auflösungsvermögen für hochautomatisiertes Fahren einerseits, sowie schnell wachsende Stückzahlen produzierter Sensoren andererseits, einen Paradigmenwechsel in naher Zukunft bewirken. Die Entwicklung von hochgradig spezialisierten Hardwarebeschleunigern könnte sich als eine praktikable Alternative etablieren - zumindest für die anspruchsvollsten Rechenschritte mit Datenraten von mehreren Gigabits pro Sekunde. In dieser Arbeit werden anwendungsspezifische Signalverarbeitungsarchitekturen für zukünftige, hochauflösende, MIMO Radarsensoren entworfen, realisiert, untersucht und optimiert. Der Fokus liegt dabei stets auf der Echtzeitfähigkeit, sodass selbst anspruchsvolle Algorithmen in einer ausreichend kurzen Zeit berechnet werden können. Die komplette Signalverarbeitungskette, beginnend von den empfangenen Signalen im Basisband bis hin zu einer Liste von Detektion, wird in dieser Arbeit behandelt. Die Kette gliedert sich im Wesentlichen in drei größere Teilschritte: Spektralanalyse, Zieldetektion und Winkelschätzung. Des Weiteren werden die entwickelten Architekturen auf einem FPGA implementiert und wichtige Kennzahlen wie Ressourcenverbrauch, Stromverbrauch oder Datendurchsatz ausgewertet und mit anderen Beispielen aus der Literatur verglichen. Ein umfangreicher Datensatz, welcher mehr als 3600 verschiedene Parametrisierungen und Varianten beinhaltet, wurde mit Hilfe einer modellbasierten Entwurfsraumexploration erstellt und ist in dieser Arbeit enthalten. Schließlich wurde ein experimenteller Radarsensor aufgebaut und dazu benutzt, die entworfenen Signalverarbeitungsarchitekturen unter realen Umgebungsbedingungen zu verifizieren