141 research outputs found

    Radio-Communications Architectures

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    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

    Architectures multi-bandes en mode impulsionnel et circuits pour des applications nomades très haut débit autour de 60GHz

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    Avec la croissance actuelle du marché des applications de transfert de données multimédia à très haut débit, les bandes de fréquences autour de 60 GHz sont une nouvelle alternative promettant des performances intéressantes en terme de débits mais soulèvent des défis techniques et technologiques au niveau des architectures et circuits. C'est dans ce cadre que s'inscrit cette thèse, qui propose une approche multi bande impulsionnelle MBOOK avec un récepteur à détection d'énergie, et qui analyse plus spécifiquement les verrous au niveau de l'émetteur. L'étude du canal de propagation à 60 GHz, basée sur les modèles de canaux du standard IEEE 802.15.3c, a permis de démontrer la potentialité de cette architecture et permet d'atteindre des débits de 2 Gbps à 2metres dans un environnement de type résidentiel. Le dimensionnement de l'architecture ainsi que des performances des principaux blocs ont conduit à plusieurs possibilités pour l'architecture de l'émetteur MBOOK à 60 GHz. Les critères ont été d'assurer un compromis performances, consommation. Une étude approfondie sur l'étude des imperfections de certains blocs critiques et l'impact sur l'impulsion transmise, et donc sur les performances du système ont été établies. Le banc de filtres, nécessaire à l'émission et à la réception, représente l'un des verrous, et nous proposons une solution de filtrage à base de lignes couplées. L'étude des solutions de génération d'impulsions, des étages de commutation, et des étages d'amplification de l'émetteur sont détaillées et discutées dans les deux derniers chapitresWith the current increasing market request concerning high speed data rates applications, the 60 GHz frequency bands seems to be one of the new promising alternatives for high data rate wireless communications. In this context, the development of new systems operating at these frequencies becomes a very attractive research subject. This study focuses on nomadic systems offering high data and reconfigurable rates, low complexity, low power consumption for short communications. One of the important tasks in the millimetre wave architecture design is to consider the channel propagation characteristics simultaneously with the technological performance of integrated circuits and antennas. This requires a co-design of the entire system. Therefore, we begun by studying the characteristics of the channel propagation channel at 60GHz according to the IEEE 802.15.3c and IEEE 802.11.ad models. This PHD thesis proposes a new transceiver architecture based on multi-band impulse mode, with On Off Keying modulation schema and non coherent receiver. This architecture is dedicated to nomadic systems offering high data and reconfigurable rates, low complexity, low power consumption for short communications. Analysis and performances for the proposed architecture are presented. More than 2 Gbps at 2 m are obtained. The imperfections of some critical blocks and their impact on the transmitted pulses were analysed and thus the performance of the system has been established. The potentiality of microstrip band pass filter bank presenting a constant relative bandwidth and reasonable insertion losses is presented in this study. The study of pulse generation solutions, switchers, amplification stages and antennas are detailed and discussed in the last two chaptersconstant relative bandwidth and reasonable insertion losses is presented in this study.The study of pulse generation solutions, switchers, amplification stages and antennas are detailed and discussed in the last two chapters.PARIS-EST-Université (770839901) / SudocSudocFranceF

    Analyse de l'influence du codage d'enveloppe sur les performances de l'amplificateur classe E d'une architecture polaire.

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    National audienceAujourd'hui on observe une augmentation de la dynamique des signaux pour les nouveaux standards. L'utilisation d'amplificateurs linéaires ne permet pas d'obtenir de forts rendements. On peut envisager d'utiliser des amplificateurs en classe commutée associés à une architecture polaire fournissant un signal à enveloppe constante. Cela grâce à un codage de l'enveloppe par un modulateur de type ΣΔ . Le but de cet article est de comprendre l'influence que peut avoir la forme d'un signal binaire sur les performances en commutation d'un amplificateur classe E conçu pour une application Wimax mobile (3.7GHz). L'article étudie les performances pour différentes répartitions probabilistes des niveaux à plusieurs fréquences de codage

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Analyse de l'influence des non-linéarités de l'amplificateur de puissance dans une liaison de communication numérique RF

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    L'OBJECTIF PRINCIPAL DE CETTE THESE EST DE PRESENTER L'INFLUENCE DES NON-LINEARITES DE L'AMPLIFICATEUR DE PUISSANCE DANS UNE LIAISON NUMERIQUE RADIO FREQUENCE. UNE ETUDE PERMET DE MONTRER L'IMPORTANCE DE LA MODELISATION DES NON-LINEARITES DE L'AMPLIFICATEUR DE PUISSANCE SUR LES GRANDEURS CARACTERISANT LES LIAISONS NUMERIQUES, TEL QUE L'ADJACENT CHANNEL POWER RATIO. (ACPR). UNE METHODE DE MODELISATION DES NON-LINEARITES D'AMPLITUDE DE L'AMPLIFICATEUR BASE SUR LE GAIN, LE POINT A 1 DB DE COMPRESSION ET LE POINT D'INTERCEPTION D'ORDRE 3EST DEVELOPPEE, AINSI QU'UN LIEN ENTRE CES GRANDEURS CARACTERISANT LES NON-LINEARITES CIRCUITS ET LA GRANDEUR CARACTERISANT LA REMONTEE SPECTRALE. UNE ETUDE PERMET DE MONTRER LA SENSIBILITE DES DIFFERENTES MODULATIONS NUMERIQUES AUX NON-LINEARITES DE L'AMPLIFICATEUR DE PUISSANCEPARIS-EST Marne-la-Vallee-BU (774682101) / SudocSudocFranceF

    Solution de filtrage reconfigurable en technologie CMOS 65nm pour les architectures d'émission numériques

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    Cette thèse porte sur les défis techniques et technologiques dans la conception des architectures mobiles d'émission tout numérique reconfigurables fonctionnant dans les bandes cellulaires pour les standards GSM, W-CDMA, HSUPA et LTE. Avec l'évolution constante des besoins en communication, les terminaux mobiles doivent être en mesure de couvrir différents standards à partir d'une même architecture, en fonction des bandes de fréquences libres, du débit et des contraintes spectrales. Dans un but de réduction des coûts, de consommation et d'une plus grande intégration, de nouvelles architectures dites multistandards se sont développées permettant à un seul émetteur d'adresser chaque standard au lieu de paralléliser plusieurs architectures radio chacune dédiée à un standard particulier. Depuis plusieurs années ont émergé des technologies nanométriques telles que le CMOS 90nm ou 65nm, ouvrant la voie à une plus grande numérisation des blocs fonctionnels des architectures jusqu'alors analogiques. Dans cette étude, nous identifions les évolutions possibles entre monde analogique et monde numérique permettant de déplacer la limite de la bande de base jusqu'à l'amplificateur de puissance. Plusieurs architectures ont été étudiées avec des degrés de numérisation progressifs jusqu'à atteindre l'architecture tout numérique englobant une partie de l'amplification de puissance. Un travail approfondi sur l'étude des différents standards cellulaires mené conjointement avec l'implémentation et la simulation de ces architectures, a permis d'identifier les différents verrous technologiques et fonctionnels dans le développement d'architectures tout numérique . Les contraintes de pollution spectrale des raies de sur-échantillonnage sont apparues comme dimensionnantes. Pour chaque bande de chaque standard, ces contraintes ont été évaluées, afin de définir une méthode d'optimisation des fréquences de sur-échantillonnage. Cependant un filtrage externe reste nécessaire. Une deuxième étape nous a amené à identifier et concevoir une technique de filtrage passe bande reconfigurable pour les bandes cellulaires de 1710 à 1980MHz avec au moins 60MHz de largeur de bande afin d'adresser le standard LTE, et 23dB d'atténuation à 390MHz du centre de la bande pour adresser le pire cas de filtrage (bandes 1, 3 et 10 en W-CDMA). Nous avons alors conçu et implémenté un filtre reconfigurable à inductances actives, afin de garantir reconfigurabilité et très faibles pertes d'insertion. Cette thèse a donc permis à partir d'une problématique actuelle et au travers d'une démarche d'identification des limites des architectures tout numérique , de proposer un prototype de filtre adapté. Ce filtre a été conçu en CMOS 65nm, réalisé et mesuré, les performances sont conformes aux exigences requisesThis thesis addresses the technical and technological challenges in the design of all digital reconfigurable mobile architectures operating cellular standard bands (GSM, WCDMA, HSUPA and LTE). With the ever-changing communication needs, mobile devices must be able to address different standards from a common architecture depending on free frequency bands, data rate and spectral constraints. In order to reduce costs, consumption and to obtain a greater integration, new architectures were developed and called multi-standard allowing a single transmitter to transmit each standard instead of parallelizing several radio architectures each dedicated to a particular standard. For several years nanoscale technologies such as 90nm or 65nm CMOS have emerged, clearing the way to replace analog functional blocks by greater digital functional blocks. In this study, we identify possible changes between "analog world" and "digital world" to move the digital boundary from the baseband to power amplifier. Several architectures have been studied with progressive digitization degrees to meet "all digital" architecture, comprising part of the power amplifier. Extensive work on the study of different cellular standards conducted jointly with the implementation and simulation of these architectures, let us identified the different technological and functional locks in the development of "all digital" architectures. Oversampling spurious constraints have emerged as dimensioning. For each band of each standard, these constraints were evaluated to define an optimization method of over-sampling frequency. However an external filter is required. A second step led us to identify and design a reconfigurable bandpass filtering technique for cellular bands from 1710 to 1980MHz with at least 60MHz of bandwidth in order to address the LTE, and 23dB attenuation at 390MHz from the center of the filter to address the most constringent filtering cases (bands 1, 3 and 10 in W-CDMA). We then designed and implemented a reconfigurable filter based on active inductors to ensure reconfigurability and very low insertion loss. This thesis permit from an actual architecture system issue and through a process to identify limitations of all digital architectures, to propose an adapted filtering solution. This filter was designed in 65nm CMOS, implemented. Measured performance is consistent with requirementsPARIS-EST-Université (770839901) / SudocSudocFranceF

    Architectures et circuits dédiés aux émetteurs Ultra Large Bande bas débit

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    PARIS-EST Marne-la-Vallee-BU (774682101) / SudocSudocFranceF

    Contribution à la modélisation des effets non linéaires dans les amplificateurs RF et micro-ondes des émetteurs de radiocommunications numériques

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    Cette thèse concerne la modélisation comportementale des amplificateurs de puissance, dernier élément d une chaîne de radiocommunication numérique. Le travail comprend, dans une première partie, une analyse comparative des modèles existants et propose un modèle basé sur les séries de Volterra classique. Ce modèle prend en compte les effets de mémoire BF et HF du composant actif. La comparaison des modèles existants et la validation est effectuée sur un signal de type OFDM présentant une grande largeur de bande et une forte dynamique d enveloppe. Une seconde partie est consacrée aux architectures de type EER utilisant des amplificateurs de puissance fonctionnant en classe E. Ces architectures permettent d obtenir des fonctionnements de type multistandards et haut rendement. Nous avons mené une étude sur les conséquences de la non idéalité des paramètres du composant actif utilisé en commutation et des conséquences sur les performances en rendementThis thesis concerns the behavioral modeling of high power amplifiers, last element of digital radio-communications chain. This work includes, in a first part, comparative analysis of the existing models and proposes a model based on the Volterra series. This model takes into account the short-term memory and long-term memory into the active component. The comparison of the existing models and the validation are carried out on a signal OFDM type presenting a great bandwidth and a high amplitude variation. A second part is devoted to architectures of EER type, this architectures employs a class E high power amplifier. These architectures make it possible to obtain an operation of the multistandards type and high efficiency. We have made a study on the consequences in term of performances and efficiency of the active device parameters non-ideality in commutation modePARIS-EST Marne-la-Vallee-BU (774682101) / SudocSudocFranceF
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