Ultra-Wideband Secure Communications and Direct RF Sampling Transceivers

Larger wireless device bandwidth results in new capabilities in terms of higher data rates and security. The 5G evolution is focus on exploiting larger bandwidths for higher though-puts. Interference and co-existence issues can also be addressed by the larger bandwidth in the 5G and 6G evolution. This dissertation introduces of a novel Ultra-wideband (UWB) Code Division Multiple Access (CDMA) technique to exploit the largest bandwidth available in the upcoming wireless connectivity scenarios. The dissertation addresses interference immunity, secure communication at the physical layer and longer distance communication due to increased receiver sensitivity. The dissertation presents the design, workflow, simulations, hardware prototypes and experimental measurements to demonstrate the benefits of wideband Code-Division-Multiple-Access. Specifically, a description of each of the hardware and software stages is presented along with simulations of different scenarios using a test-bench and open-field measurements. The measurements provided experimental validation carried out to demonstrate the interference mitigation capabilities. In addition, Direct RF sampling techniques are employed to handle the larger bandwidth and avoid analog components. Additionally, a transmit and receive chain is designed and implemented at 28 GHz to provide a proof-of-concept for future 5G applications. The proposed wideband transceiver is also used to demonstrate higher accuracy direction finding, as much as 10 times improvement

A QPSK 110-Gb/s Polarization-Diversity MIMO Wireless Link with a 220-255 GHz Tunable LO in a SiGe HBT Technology

In this article, a polarization-diversity technique multiple-input multiple-output (MIMO) is demonstrated to double the spectral efficiency of a line-of-sight quadrature phase-shift keying (QPSK) wireless link at 220-255 GHz with a pair of highly integrated single-chip transmitter (TX) and receiver (RX) front-end modules in 0.13-µ {m SiGe HBT technology ( fTmax=350 /550 GHz) exploiting only a low-cost wire-bonded chip-on-board packaging solution for high-speed baseband (BB) signals. Both TX and RX chips accommodate two independent fundamentally operated direct-conversion in-phase and quadrature (IQ) paths with separately tunable on-chip multiplier-based ( × 16 ) local oscillator (LO) generation paths driven from a single external highly stable 13.75-16-GHz frequency synthesizer. On the RX side, a mixer-first architecture is implemented to improve the symmetry between upper and lower sidebands (USB and LSB) at the cost of an increased noise figure (NF), whereas, on the TX chip, each upconversion mixer is followed by a gain-bandwidth (BW)-limited four-stage power amplifier (PA) to support the link budget at a meter distance. Next, two independent IQ data streams from the upconversion/downconversion paths on each chip are directed to a common lens-coupled broadband on-chip slot antenna system. This way, two orthogonal circular polarizations [left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP)] can be transmitted with sufficient isolation for link operation without the need for a high-speed depolarizer in the BB for any relative orientation between TX and RX modules. The antenna combined with a 9-mm diameter Si-lens provides a directivity of 23.5-27 dBi at 210-270 GHz for each of the modules. This, along with a peak radiated power of 7.5 dBm/ch from the TX module, and the cascaded conversion gain (CG)/single sideband (SSB) NF of 18/18 dB/ch for the RX module followed by a broadband amplifier (PSPL5882) from Tektronix allowed successful transmission of two independent QPSK data streams with an aggregate speed of 110 and 80 Gb/s over 1 and 2 m, respectively, at 230 GHz with a board-level limited channel BB bandwidth (BW) of 13.5 GHz. © 1963-2012 IEEE

Radio-Communications Architectures

Wireless communications, i.e. radio-communications, are widely used for our different daily needs. Examples are numerous and standard names like BLUETOOTH, WiFI, WiMAX, UMTS, GSM and, more recently, LTE are well-known [Baudoin et al. 2007]. General applications in the RFID or UWB contexts are the subject of many papers. This chapter presents radio-frequency (RF) communication systems architecture for mobile, wireless local area networks (WLAN) and connectivity terminals. An important aspect of today's applications is the data rate increase, especially in connectivity standards like WiFI and WiMAX, because the user demands high Quality of Service (QoS). To increase the data rate we tend to use wideband or multi-standard architecture. The concept of software radio includes a self-reconfigurable radio link and is described here on its RF aspects. The term multi-radio is preferred. This chapter focuses on the transmitter, yet some considerations about the receiver are given. An important aspect of the architecture is that a transceiver is built with respect to the radio-communications signals. We classify them in section 2 by differentiating Continuous Wave (CW) and Impulse Radio (IR) systems. Section 3 is the technical background one has to consider for actual applications. Section 4 summarizes state-of-the-art high data rate architectures and the latest research in multi-radio systems. In section 5, IR architectures for Ultra Wide Band (UWB) systems complete this overview; we will also underline the coexistence and compatibility challenges between CW and IR systems

Sensing Integrated DFT-Spread OFDM Waveform and Deep Learning-powered Receiver Design for Terahertz Integrated Sensing and Communication Systems

Terahertz (THz) communications are envisioned as a key technology of next-generation wireless systems due to its ultra-broad bandwidth. One step forward, THz integrated sensing and communication (ISAC) system can realize both unprecedented data rates and millimeter-level accurate sensing. However, THz ISAC meets stringent challenges on waveform and receiver design to fully exploit the peculiarities of THz channel and transceivers. In this work, a sensing integrated discrete Fourier transform spread orthogonal frequency division multiplexing (SI-DFT-s-OFDM) system is proposed for THz ISAC, which can provide lower peak-to-average power ratio than OFDM and is adaptive to flexible delay spread of the THz channel. Without compromising communication capabilities, the proposed SI-DFT-s-OFDM realizes millimeter-level range estimation and decimeter-per-second-level velocity estimation accuracy. In addition, the bit error rate (BER) performance is improved by 5 dB gain at the $10^{-3}$ BER level compared with OFDM. At the receiver, a deep learning based ISAC receiver with two neural networks is developed to recover transmitted data and estimate target range and velocity, while mitigating the imperfections and non-linearities of THz systems. Extensive simulation results demonstrate that the proposed deep learning methods can realize mutually enhanced performance for communication and sensing, and is robust against Doppler effects, phase noise, and multi-target estimation

Etude système de diodes lasers à verrouillage de modes pour la radio-sur-fibre en bande millimétrique

Ce travail de thèse s inscrit dans la recherche des solutions économiquementviables pour des réseaux personnels à hauts débits (plusieurs Gbps à plusieursdizaines de Gbps) opérationnels en bande millimétrique autour de 60 GHz. Aucas où ces réseaux servent un nombre élevé d utilisateurs, ils comprendront unemultitude d antennes afin d assurer l accès sans fil rapide. Afin de réduire aumaximum le coût d un module d antenne, les réseaux doivent fournir un signalanalogue à des porteuses millimetriques. Une solution prometteuse pour les systèmesde distribution qui correspond à ces besoins sont des structures à fibreoptique, laquelle permet une transmission à faibles pertes et à haute bande passante.On parle de l approche "radio-sur-fibre" (en anglais, radio-over-fiber). Laproblématique est de pouvoir générer et moduler un signal aux fréquences millimétriqueslors de la transmission optique - et ce avec des composant bas coûts.La technique utilisée dans le cadre de cette thèse est l emploi des diodes laser àverrouillage de modes. Ces derniers vont pouvoir générer des hautes fréquencestout en ne nécessitant qu une alimentation continue, et ils peuvent être modulésde manière directe ou externe. Les lasers à semi-conducteurs employés ici sontd une génération encore à l état d étude puisqu il s agit des lasers à boites (ouîlots) quantiques. Ces lasers ont montrés de très bonnes capacités à générer dessignaux électriques aux fréquences autour de 60 GHz, bien qu ayant encore, pourl instant, à une stabilité de fréquence (ou de phase) limitée. Dans le cadre des systèmesde communication opto/micro-ondes, peu de travaux approfondis ont étémenés sur ces structures.Au cours de cette thèse, plusieurs études ont été effectuées. La première portesur les propriétés générales d un système construit à partir de ce type de laser(puissances disponibles, figure de bruit, linéarité etc.). Une deuxième étude aété consacrée aux effets de la propagation des signaux dans les systèmes baséssur les lasers à verrouillage de modes, notamment de la dispersion chromatiquelaquelle a un effet considérable sur les distances de transmission. Les deux étudesmettent en avant l importance d une limitation du nombre de modes générés parla diode laser afin d optimiser non seulement le gain du lien et la puissance RFrécupérée, mais aussi la figure de bruit du système. Lors d une troisième étude, lastabilité en fréquence/phase s est révélée critique, car le bruit de fréquence/phaselimite la qualité de la transmission en introduisant un plancher d erreur mêmepour des rapports signal-a-bruit très élevés. Des différentes générations de lasersà boites (îlots) quantiques et à verrouillage de modes ont été testées. Le problèmedu bruit de fréquence et de phase persiste et ne peut pas être résolu en utilisantles techniques classiques comme les boucles à verrouillage de phase conventionnelles.Une solution pour ce problème a été développée pour les systèmes detransmission; elle permet simultanément un ajustement de fréquence supérieure(précision de quelques Hz à quelques kHz) à celle donnée par le processus de fabricationdes diodes lasers (précision de quelques GHz), ainsi qu une stabilisationde fréquence et de phase.This dissertation is related to the search for an economically sustainable solutionfor high data rate (several Gbps to several tens of Gbps) personal area networksoperating in the millimeter-wave region around 60 GHz. If such networks supplya large number of users, they need to encompass a multitude of antenna pointsin order to assure wireless access to the network. With the aim of reducing thecost of an antenna module, the networks should at best provide quasi "readyto-radiate" signals to the modules, i.e. at millimeter-wave carrier frequencies.Thanks to their low transmission loss and their high bandwidth, optical fiber distributionarchitectures represent a promising solution. The technique is referredto as the so-called "radio-over-fiber" approach whereby the analog radio signalwill be transported to the access point by an optical wave. The challenge herebyis the generation and modulation of an optical signal by a millimeter-wave radiosignal using preferably cost-efficient system components. The technique proposedherein is based on the use of mode-locked laser diodes which can generatesignals at very high frequencies under the condition of continuous current supply.Mode-locked laser diodes can be modulated both directly and externally. Thediodes employed in this work are based on so-called quantum dots (or quantumdashes); these are material structures which are themselves still subject to intensivephysical research. Signals at millimeter-wave frequencies (around 60 GHz)can easily be generated by such lasers. However, their frequency and phase stabilityis as yet limited. In the context of radio-over-fiber communication systems,these structures have not yet been studied in detail.In the course of this dissertation, several aspects are considered. A first systemstudy treats the basic properties of a system built from this type of laser source(available signal power, system noise figure, linearity etc.). A second study isdevoted to an investigation of propagation effects like dispersion, which considerablyinfluence the attainable transmission distances. An essential result of bothstudies is the importance of limiting the laser spectrum to a small number of lasermodes for an optimization of link gain, generated RF power, and system noisefigure. A third study deals with the limited frequency and phase stability whichturn out to be critical factors for transmission quality. The study of several generationsof quantum dot/dash lasers has revealed that the problems of frequencyand phase noise persist and cannot be solved using classical techniques involvinge.g. conventional phase-locked loops. In this dissertation, a solution is presentedwhich not only allows a more precise adjustment of the laser frequency (precisionin the order of Hz to kHz) than that given by the manufacturing process of thelaser (precision in the order of GHz), but also enables a stabilization of frequencyand phase.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Etude système de diodes lasers à verrouillage de modes pour la radio-sur-fibre en bande millimétrique

Ce travail de thèse s inscrit dans la recherche des solutions économiquementviables pour des réseaux personnels à hauts débits (plusieurs Gbps à plusieursdizaines de Gbps) opérationnels en bande millimétrique autour de 60 GHz. Aucas où ces réseaux servent un nombre élevé d utilisateurs, ils comprendront unemultitude d antennes afin d assurer l accès sans fil rapide. Afin de réduire aumaximum le coût d un module d antenne, les réseaux doivent fournir un signalanalogue à des porteuses millimetriques. Une solution prometteuse pour les systèmesde distribution qui correspond à ces besoins sont des structures à fibreoptique, laquelle permet une transmission à faibles pertes et à haute bande passante.On parle de l approche "radio-sur-fibre" (en anglais, radio-over-fiber). Laproblématique est de pouvoir générer et moduler un signal aux fréquences millimétriqueslors de la transmission optique - et ce avec des composant bas coûts.La technique utilisée dans le cadre de cette thèse est l emploi des diodes laser àverrouillage de modes. Ces derniers vont pouvoir générer des hautes fréquencestout en ne nécessitant qu une alimentation continue, et ils peuvent être modulésde manière directe ou externe. Les lasers à semi-conducteurs employés ici sontd une génération encore à l état d étude puisqu il s agit des lasers à boites (ouîlots) quantiques. Ces lasers ont montrés de très bonnes capacités à générer dessignaux électriques aux fréquences autour de 60 GHz, bien qu ayant encore, pourl instant, à une stabilité de fréquence (ou de phase) limitée. Dans le cadre des systèmesde communication opto/micro-ondes, peu de travaux approfondis ont étémenés sur ces structures.Au cours de cette thèse, plusieurs études ont été effectuées. La première portesur les propriétés générales d un système construit à partir de ce type de laser(puissances disponibles, figure de bruit, linéarité etc.). Une deuxième étude aété consacrée aux effets de la propagation des signaux dans les systèmes baséssur les lasers à verrouillage de modes, notamment de la dispersion chromatiquelaquelle a un effet considérable sur les distances de transmission. Les deux étudesmettent en avant l importance d une limitation du nombre de modes générés parla diode laser afin d optimiser non seulement le gain du lien et la puissance RFrécupérée, mais aussi la figure de bruit du système. Lors d une troisième étude, lastabilité en fréquence/phase s est révélée critique, car le bruit de fréquence/phaselimite la qualité de la transmission en introduisant un plancher d erreur mêmepour des rapports signal-a-bruit très élevés. Des différentes générations de lasersà boites (îlots) quantiques et à verrouillage de modes ont été testées. Le problèmedu bruit de fréquence et de phase persiste et ne peut pas être résolu en utilisantles techniques classiques comme les boucles à verrouillage de phase conventionnelles.Une solution pour ce problème a été développée pour les systèmes detransmission; elle permet simultanément un ajustement de fréquence supérieure(précision de quelques Hz à quelques kHz) à celle donnée par le processus de fabricationdes diodes lasers (précision de quelques GHz), ainsi qu une stabilisationde fréquence et de phase.This dissertation is related to the search for an economically sustainable solutionfor high data rate (several Gbps to several tens of Gbps) personal area networksoperating in the millimeter-wave region around 60 GHz. If such networks supplya large number of users, they need to encompass a multitude of antenna pointsin order to assure wireless access to the network. With the aim of reducing thecost of an antenna module, the networks should at best provide quasi "readyto-radiate" signals to the modules, i.e. at millimeter-wave carrier frequencies.Thanks to their low transmission loss and their high bandwidth, optical fiber distributionarchitectures represent a promising solution. The technique is referredto as the so-called "radio-over-fiber" approach whereby the analog radio signalwill be transported to the access point by an optical wave. The challenge herebyis the generation and modulation of an optical signal by a millimeter-wave radiosignal using preferably cost-efficient system components. The technique proposedherein is based on the use of mode-locked laser diodes which can generatesignals at very high frequencies under the condition of continuous current supply.Mode-locked laser diodes can be modulated both directly and externally. Thediodes employed in this work are based on so-called quantum dots (or quantumdashes); these are material structures which are themselves still subject to intensivephysical research. Signals at millimeter-wave frequencies (around 60 GHz)can easily be generated by such lasers. However, their frequency and phase stabilityis as yet limited. In the context of radio-over-fiber communication systems,these structures have not yet been studied in detail.In the course of this dissertation, several aspects are considered. A first systemstudy treats the basic properties of a system built from this type of laser source(available signal power, system noise figure, linearity etc.). A second study isdevoted to an investigation of propagation effects like dispersion, which considerablyinfluence the attainable transmission distances. An essential result of bothstudies is the importance of limiting the laser spectrum to a small number of lasermodes for an optimization of link gain, generated RF power, and system noisefigure. A third study deals with the limited frequency and phase stability whichturn out to be critical factors for transmission quality. The study of several generationsof quantum dot/dash lasers has revealed that the problems of frequencyand phase noise persist and cannot be solved using classical techniques involvinge.g. conventional phase-locked loops. In this dissertation, a solution is presentedwhich not only allows a more precise adjustment of the laser frequency (precisionin the order of Hz to kHz) than that given by the manufacturing process of thelaser (precision in the order of GHz), but also enables a stabilization of frequencyand phase.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF