The concepts of a digital twin and extended reality have recently emerged, which require a massive amount of sensor data to be transmitted with low latency and high reliability. For low-latency communications, joint source-channel coding (JSCC) is an attractive method for error correction coding and compared to highly complex digital systems that are currently in use. I propose the use of complex-valued and quaternionic neural networks (QNN) to decode JSCC codes, where the complex-valued neural networks show a significant improvement over real-valued networks and the QNNs have an exceptionally high performance. Furthermore, I propose mapping encoded JSCC code words to the baseband of the frequency domain in order to enable time/frequency synchronization as well as to mitigate fading using robust estimation theory. Additionally, I perform robust statistical signal processing on the high-dimensional JSCC code showing significant noise immunity with drastic performance improvements at low signal-to-noise ratio (SNR) levels. The performance of the proposed JSCC codes is within 5 dB of the optimal performance theoretically achievable and outperforms the maximum likelihood decoder at low SNR while exhibiting the smallest possible latency. I designed a Bayesian minimum mean square error estimator for decoding high-dimensional JSCC codes achieving 99.96% accuracy. With the recent introduction of electromagnetic reconfigurable intelligent surfaces (RIS), a paradigm shift is currently taking place in the world of wireless communications. These new technologies have enabled the inclusion of the wireless channel as part of the optimization process. In order to decode polarization-space modulated RIS reflections, robust polarization state decoders are proposed using the Weiszfeld algorithm and an generalized Huber M-estimator. Additionally, QNNs are trained and evaluated for the recovery of the polarization state. Furthermore, I propose a novel 64-ary signal constellation based on scaled and shifted Eisenstein integers and generated using media-based modulation with a RIS. The waveform is received using an antenna array and decoded with complex-valued convolutional neural networks. I employ the circular cross-correlation function and a-priori knowledge of the phase angle distribution of the constellation to blindly resolve phase offsets between the transmitter and the receiver without the need for pilots or reference signals. Furthermore, the channel attenuation is determined using statistical methods exploiting that the constellation has a particular distribution of magnitudes. After resolving the phase and magnitude ambiguities, the noise power of the channel can also be estimated. Finally, I tune an Sq-estimator to robustly decode the Eisenstein waveform. / Doctor of Philosophy / This dissertation covers three novel wireless communications methods; analog coding, communications using the electromagnetic polarization and communications with a novel signal constellation. The concepts of a digital twin and extended reality have recently emerged, which require a massive amount of sensor data to be transmitted with low latency and high reliability. Contemporary digital communication systems are highly complex with high reliability at the expense of high latency. In order to reduce the complexity and hence latency, I propose to use an analog coding scheme that directly maps the sensor data to the wireless channel. Furthermore, I propose the use of neural networks for decoding at the receiver, hence using the name neural receiver. I employ various data types in the neural receivers hence leveraging the mathematical structure of the data in order to achieve exceptionally high performance. Another key contribution here is the mapping of the analog codes to the frequency domain enabling time and frequency synchronization. I also utilize robust estimation theory to significantly improve the performance and reliability of the coding scheme. With the recent introduction of electromagnetic reconfigurable intelligent surfaces (RIS), a paradigm shift is currently taking place in the world of wireless communications. These new technologies have enabled the inclusion of the wireless channel as part of the optimization process. Therefore, I propose to use the polarization state of the electromagnetic wave to convey information over the channel, where the polarization is determined using a RIS. As with the analog codes, I also extensively employ various methods of robust estimation to improve the performance of the recovery of the polarization at the receiver. Finally, I propose a novel communications signal constellation generated by a RIS that allows for equal probability of error at the receiver. Traditional communication systems utilize reference symbols for synchronization. In this work, I utilize statistical methods and the known distributions of the properties of the transmitted signal to synchronize without reference symbols. This is referred to as blind channel estimation. The reliability of the third communications method is enhanced using a state-of-the-art robust estimation method.

Impulse Ultra Wideband (UWB) communications is an emerging technology that promises a number of benefits over traditional narrowband or broadband signals: extremely high data rates, extremely robust operation in dense multipath environments, low probability of intercept/detection, and the ability to operate concurrently with existing users. Unfortunately, most currently available UWB systems are based on dedicated hardware, preventing researchers from investigating algorithms or architectures that take advantage of some of the unique properties of UWB signals. This dissertation outlines the development of a general purpose software radio transceiver testbed for UWB signals. The testbed is an enabling technology that provides a development platform for investigating ultra wideband communication algorithms (e.g., acquisition, synchronization, modulation, multiple access), ranging or radar (e.g., precision position location, intrusion detection, heart and respiration rate monitoring), and could potentially be used in the area of ultra wideband based medical imaging or vital signs monitoring. As research into impulse ultra wideband expands, the need is greater now than ever for a platform that will allow researchers to collect real-world performance data to corroborate theoretical and simulation results. Additionally, this dissertation outlines the development of the Time-Interleaved Analog to Digital Converter array which served as the core of the testbed, along with a comprehensive theoretical and simulation-based analysis on the effects of Analog to Digital Converter mismatches in a Time-Interleaved Sampling array when the input signal is an ultra wideband Gaussian Monocycle. Included in the discussion is a thorough overview of the implementation of both a scaled-down prototype as well as the final version of the testbed. This dissertation concludes by evaluating the of the transceiver testbed in terms of the narrowband dynamic range, the accuracy with which it can sample and reconstruct a UWB pulse, and the bit error rate performance of the overall system. / Ph. D.

In radio frequency (RF), filtering is an essential part of RF transceivers. They are employed for different purposes of band selection, channel selection, interference cancellation, image rejection, etc. These are all translated in selecting the wanted signal while mitigating the rest. This can be performed by either selecting the desired frequency range by a band pass filter or rejecting the unwanted part by a band stop filter. Although there has been tremendous effort to design RF tunable filters, there is still lack of designs with frequency and bandwidth software-tuning capability at frequencies above 4 GHz. This prevents the implementation of Software Defined Radios (SDR) where software tuning is a critical part in supporting multiple standards and frequency bands. Designing a tunable integrated filter will not only assist in realization of SDR, but it also causes an enormous shrinkage in the size of the circuit by replacing the current bulky off-chip filters. The main purpose of this research is to design integrated band pass and band stop filters aimed to perform interference cancellation. In order to do so, two systems are proposed for this thesis. The first system is a band pass filter capable of frequency and band with tuning for C band frequency range (4-8 GHz) and is implemented in 0.13 µm BiCMOS technology. Frequency tunability is accomplished by using a variable capacitor (varactor) and bandwidth tuning is carried out by employing a negative transconductance cell to compensate for the loss of the elements. Additional circuitry is added to the band pass filter to enhance the selectivity of the filter. The second system is a band stop filter (notch) with the same capability as the band pass filter in terms of tuning. This system is implemented in C band, similar to its band stop counterpart and is capable of tuning its depth by using a negative transconductance in an LC tank. A negative feedback is added to the circuit to improve the bandwidth. While implemented in the same process as the band pass filter, it only employs CMOS transistors since it is generally more attractive due to its lower cost and scalability. Both of the systems mentioned use a varactor for changing the center frequency which is a nonlinear element. Therefore, the nonlinearity of it is modelled using two different methods of nonlinear feedback and Volterra series in order to gain further understanding of the nonlinear process taking place in the LC tank. After the validation of the models proposed using Cadence Virtuoso simulator, two methods of design and tuning are suggested to improve the linearity of the system. After post layout-extraction, the band pass filter is capable of Q tuning in the range of 3 to 270 and higher. With the noise figure of 10 to 14 dB and input 1-dB compression point as high as 2 dBm, the system shows a reasonably good performance along its operating frequency of 4 to 8 GHz. The band stop filter which is designed in the same frequency band can achieve better than 55 dB of rejection with the noise figure of 6.7 to 8.8 dB and 1-dB compression point of -4 dBm. With the power consumption of 39 to 70 mW, the band stop filter can be used in a low power receiver to suppress unwanted signals. The technique used in the band stop filter can be applied to higher frequency ranges if the circuit is implemented in a more advanced silicon technology. Implementing the mentioned filters in a receiver along with other elements of low noise amplifiers, mixers, etc. would be a major step toward full implementation of SDR systems. Studying the linearity theory of varactors would help future designers identify the sources of nonlinearity and suggest more efficient tuning techniques to improve the linearity of RF electronic systems. / Master of Science

Denna studie genomför en detaljerad undersökning av två olika plattformar för programvarudefinierad radio (SDR), GNU Radio och Simulink, för att avgöra vilken som är mest lämpad för integration i en specifik kurs inom läroplanen vid mittuniversitet. Utvärderingen fokuserar på nyckelprestandamått såsom beräkningskapacitet, simuleringens hastighet och visualiseringsförmåga, vilket ger en omfattande jämförelse mellan dessa två plattformar. Undersökningen inleds med att simulera det fysiska lagret av WiFi, vilket är ett grundläggande krav för kursens laboratoriearbete. Studiens omfattning utvidgas sedan för att inkludera simuleringar av andra nätverkstekniker som 4G. Denna expansion syftar till att samla in omfattande data för en mer noggrann jämförelse och för att grundligt utvärdera varje plattforms förmåga att hantera olika nätverkssimuleringar. Dessutom fördjupar studien sig i olika simuleringstekniker genom att diskutera två distinkta angreppssätt till SDR-simuleringar, vilket belyser deras respektive styrkor och tillämpbarhet i ett utbildningssammanhang. Det slutgiltiga målet med denna forskning är att avgöra om GNU Radio erbjuder betydande fördelar jämfört med MATLABs Simulink och om det bör ersätta Simulink som det primära verktyget som används i denna kurs. I förväntan på potentiella förändringar har nya alternativa laborationsinstruktioner för GNU Radio också utvecklats och presenterats. Dessa instruktioner är utformade för att underlätta en smidig övergång om universitetet beslutar att anta GNU Radio, för att säkerställa att utbildningsmålen fortsätter att uppnås på ett effektivt och effektivt sätt. Även om studien visar att GNU Radio erbjuder bättre beräkningskapacitet var själva simuleringsprocessen något svårare. De två plattformarna uppnådde nästan samma resultat, men GNU Radio krävde extra arbete. Med tanke på att inlärningsresultaten var liknande men inlärningsprocessen med GNU Radio var mer komplicerad bedömdes GNU Radio som olämplig för denna kurs. / This study conducts a detailed examination of two distinct Software Defined Radio (SDR) platforms, GNU Radio and Simulink, to ascertain which is more suited for integration into a specific course within the curriculum at Mid University. The evaluation focuses on key performance metrics such as computing efficiency, simulation speed, and visualization capabilities, providing a comprehensive comparison between these two platforms. The investigation begins by simulating the physical layer of WiFi, which is a fundamental requirement of the course laboratory work. The scope of the study is then broadened to include simulations of other network technologies like 4G. This expansion aims to collect extensive data for a more accurate comparison and to thoroughly evaluate the capabilities of each platform in handling various network simulations. Moreover, the study delves into different simulation methodologies by discussing two distinct approaches to SDR simulations, highlighting their respective strengths and applicabilities in an educational context. The ultimate objective of this study is to determine whether GNU Radio offers a significant advantage over MATLAB’s Simulink and if it should replace Simulink as the primary tool used in this course. In anticipation of potential changes, new alternative laboratory instructions for GNU Radio are also developed and presented. These instructions are designed to facilitate a smooth transition should the university decide to adopt GNU Radio, ensuring that educational goals continue to be met efficiently and effectively. While the study shows that GNU Radio offers better computing efficiency, the process of simulating was somewhat more challenging. The two platforms accomplished almost the same tasks, but GNU Radio required extra effort. Considering that the learning outcomes were similar but the learning process with GNU Radio was more difficult, GNU Radio was deemed unsuitable for this course.

[ES] Las redes industriales de sensores inalámbricos (IWSN - Industrial Wireless Sensor Networks) tienen una creciente aceptación en los entornos productivos debido a su facilidad de despliegue, bajos costes y eficiencia energética. Sin embargo, la complejidad y precisión que demandan estos entornos requieren que las IWSN implementen mecanismos de calidad de servicio (QoS) que les permitan operar con un alto determinismo. Por esta razón, el estándar IEEE 802.15.4e ha incorporado protocolos de acceso al medio que permiten tener un mayor control sobre las comunicaciones. Estos protocolos permiten asignar de forma predecible y cíclica instantes de tiempo donde los dispositivos de una red pueden transmitir información sin ningún tipo de interferencia o contienda con otros dispositivos de la red. Uno de ellos es el protocolo salto de canal con ranuras de tiempo (TSCH - Time Slotted Channel Hopping) el cual planifica las transmisiones entre los dispositivos en una matriz de dos dimensiones, tiempo y frecuencia. Esta planificación de las transmisiones permite que los dispositivos tengan instantes de tiempo exclusivos para la transmisión, reduciendo así la interferencia y aumentando la fiabilidad de las transmisiones. Sin embargo, este estándar no especifica como asignar los recursos temporales en la planificación TSCH, dando lugar a múltiples soluciones de planificación. Estos enfoques de planificación adquieren una gran relevancia en el actual entorno de la Industria 4.0, donde se busca aumentar de forma masiva la digitalización la interacción y la integración con los diferentes procesos industriales. Por lo tanto, hay una gran diversidad de flujos de información sobre la misma red. Además, al ser flujos de diferentes procesos, también tienen diferentes criticidades, donde deben garantizarse parámetros de QoS como latencia, throughtput, pérdida de paquetes y deadline. Esta creciente demanda de QoS y la diversidad de flujos de tráfico requieren un control estricto y dinámico que no puede lograrse con planificadores convencionales. Por esto, la evolución hacia nuevos paradigmas como las redes definidas por software (SDN - Software Defined Networks) se está convirtiendo en una interesante alternativa para abordar la complejidad de los retos actuales en las IWSN. Estas aceptan un aumento del tráfico de señalización a cambio de ventajas adicionales, tales como: una reducción de la complejidad de los procesos en los nodos, una visión global de todos los elementos de la red y una alta capacidad de reconfiguración. En el desarrollo de esta tesis, se aprovecha el alto nivel de detalle y control que ofrecen las SDN para abordar los complejos desafíos que enfrenta actualmente la adopción de las IWSN en el sector industrial, como la movilidad, la escalabilidad y la garantía de parámetros de QoS. Estos desafíos presentan una complejidad significativa al utilizar los protocolos convencionales; por ello, es necesario implementar un cambio disruptivo que permita superar estas limitaciones de manera sencilla y eficiente. En consecuencia, esta tesis se centra en la investigación y aplicación de mecanismos que permitan adaptar las IWSN al paradigma SDN, así como el desarrollo de protocolos de enrutamiento y planificación TSCH dinámicos que aseguren un alto grado de determinismo y una alta capacidad de adaptación a los cambios en la topología. De esta forma, se garantizan requisitos de QoS independientes para cada tipo de flujo de manera dinámica y con una baja complejidad, incluso en condiciones de movilidad y alta densidad de nodos. / [CA] Les xarxes industrials de sensors sense fils (IWSN - Industrial Wireless Sensor Networks) tenen una creixent acceptació en els entorns productius a causa de la seua facilitat de desplegament, baixos costs i eficiència energètica. No obstant això, la complexitat i precisió que demanden aquests entorns requerixen que les IWSN implementen mecanismes de qualitat de servici (QoS) que els permeten operar amb un alt determinisme. Per aquesta raó, l'estàndard IEEE 802.15.4e ha incorporat protocols d'accés al medi que permeten tindre un major control sobre les comunicacions. Aquest protocols permeten assignar de manera predictible i cíclica instants de temps on els dispositius d'una xarxa poden transmetre informació sense cap mena d'interferència o contesa amb altres dispositius de la xarxa. Un d'ells és el protocol salte de canal amb espais de temps (TSCH - Time Slotted Channel Hopping) el qual planifica les transmissions entre els dispositius en una matriu de dos dimensions, temps i freqüència. Aquesta planificació de les transmissions permet que els dispositius tinguen instants de temps exclusius per a la transmissió, reduint així la interferència i augmentant la fiabilitat de les transmissions. No obstant això, aquest estàndard no especifica com assignar els recursos temporals en la planificació TSCH, donant lloc a múltiples solucions de planificació. Aquest enfocaments de planificació adquireixen una gran rellevància en l'actual entorn de la Indústria 4.0, on es busca augmentar de manera massiva la digitalització, la interacció i la integració amb els diferents processos industrials. Per tant, hi ha una gran diversitat de fluxos d'informació sobre la mateixa xarxa. A més, en ser fluxos de diferents processos, també tenen diferents criticitats, on han de garantir-se paràmetres de QoS com a latència, throughtput, pèrdua de paquets i deadline. Aquesta creixent demanda de QoS i la diversitat de fluxos de trànsit requerixen un control estricte i dinàmic que no pot aconseguir-se amb planificadors convencionals. Per això, l'evolució cap a nous paradigmes com les xarxes definides per programari (SDN - Software Defined Networks) s'està convertint en una interessant alternativa per a abordar la complexitat dels reptes actuals en les IWSN. Aquestes accepten un augment del trànsit de senyalització a canvi d'avantatges addicionals, com ara: una reducció de la complexitat dels processos en els nodes, una visió global de tots els elements de la xarxa i una alta capacitat de reconfiguració. En el desenvolupament d'aquesta tesi, s'aprofita l'alt nivell de detall i control que oferixen les SDN per a abordar els complexos reptes que enfronta actualment l'adopció de les IWSN en el sector industrial, com la mobilitat, l'escalabilitat i la garantia de paràmetres de QoS. Aquests reptes presenten una complexitat significativa en utilitzar els protocols convencionals; per això, és necessari implementar un canvi transgressor que permeta superar aquestes limitacions de manera senzilla i eficient. En conseqüència, aquesta tesi se centra en la investigació i aplicació de mecanismes que permeten adaptar les IWSN al paradigma SDN, així com el desenvolupament de protocols d'encaminament i planificació TSCH dinàmics que asseguren un alt grau de determinisme i una alta capacitat d'adaptació als canvis en la topologia. D'aquesta manera, es garanteixen requisits de QoS independents per a cada tipus de flux de manera dinàmica i amb una baixa complexitat, fins i tot en condicions de mobilitat i alta densitat de nodes. / [EN] Industrial Wireless Sensor Networks (IWSNs) are becoming increasingly popular in production environments due to their ease of deployment, low cost and energy efficiency. However, the complexity and accuracy demanded by these environments require IWSNs to implement quality of service (QoS) mechanisms that allow them to operate with high determinism. For this reason, the IEEE 802.15.4e standard has incorporated medium access protocols that allow for greater control over communications. These protocols enable predictable and cyclic allocation of time slots where devices in a network can transmit information without any interference or contention with other devices in the network. One such protocol is the Time Slotted Channel Hopping (TSCH) protocol, which schedules transmissions between devices using a two-dimensional matrix of time and frequency. This scheduling of transmissions allows devices to have unique time slots for transmission, thereby reducing interference and increasing the reliability of transmissions. However, this standard does not specify how to allocate time resources in TSCH scheduling, leading to multiple scheduling solutions such as centralized scheduling, distributed scheduling, and hybrid scheduling, each with its own advantages and disadvantages. These planning approaches become highly relevant in today's Industry 4.0 environment, where digitisation, interaction and integration with different industrial processes are being massively increased. Therefore, there is a great diversity of information flows over the same network. Moreover, as they are flows of different processes, they also have different criticalities, where QoS parameters such as latency, throughput, packet loss, and deadline must be guaranteed. This increasing QoS demand and the diversity of traffic flows require strict and dynamic control that cannot be achieved with conventional schedulers. Therefore, the evolution towards new paradigms such as Software Defined Networks (SDN) is becoming an interesting alternative to address the complexity of today's challenges in IWSNs. SDNs, in the context of IWSNs, refer to the use of software to manage and control the network, allowing for a more efficient and dynamic allocation of resources. They accept an increase in signalling traffic in exchange for additional benefits, such as: a reduction of the complexity of processes at the nodes, a global view of all network elements and a high reconfiguration capacity. In the development of this thesis, the high level of detail and control offered by SDNs is leveraged to address the complex challenges currently facing the adoption of IWSNs in the industrial sector, such as mobility, scalability and QoS parameter guarantees. These challenges present significant complexity when using conventional protocols; therefore, a disruptive change needs to be implemented to overcome these limitations in a simple and efficient manner. Consequently, this thesis focuses on the investigation and implementation of specific mechanisms, such as dynamic resource allocation and traffic prioritization, to adapt IWSNs to the SDN paradigm. Additionally, new protocols, including dynamic TSCH routing and scheduling protocols, are being developed to ensure a high degree of determinism and a high adaptability to topology changes. In this way, independent QoS requirements for each flow type are guaranteed dynamically and with low complexity, even under conditions of mobility and high node density. / Esta tesis ha sido financiada por las siguientes entidades y proyectos: Instituto Tecnológico de Informática - Proyecto HYPERFACTORY: Arquitecturas, herramientas y servicios para la creación de factorías hiperconectadas: IVACE (IMDEEA/2020/68; IMDEEA/2021/87) / European Commision, IVACE 101007273; IMAMCN/2021/1 - Proyecto: DAIS: Distributed Artificial Intelligent System / Orozco Santos, F. (2024). Diseño y evaluación de redes definidas por software para la orquestación dinámica de calidad de servicio en redes industriales de sensores inalámbricos [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/211263

Αντικείμενο της διδακτορικής διατριβής αποτελεί η μελέτη και ανάλυση των μηχανισμών συγχρονισμού που εφαρμόζονται σε ψηφιακούς δορυφορικούς δέκτες διαγραμμάτων αστερισμού πολλαπλών δακτυλίων με σκοπό την ανάπτυξη νέων τεχνικών που παρουσιάζουν βελτιωμένη απόδοση καθώς και μεθόδων αξιολόγησης της απόδοσής τους. Οι σύγχρονες τάσεις στον τομέα των ψηφιακών επικοινωνιών και συγκεκριμένα στο πεδίο των τεχνικών διαμόρφωσης και διόρθωσης σφαλμάτων, καθώς και η εντεινόμενη ανάγκη για πιο αποδοτικές εφαρμογές και υπηρεσίες μέσω δορυφορικών ζεύξεων οδήγησαν στην ανάπτυξη νέων προτύπων δορυφορικών επικοινωνιών, όπως το DVB-S2, από τον Ευρωπαϊκό Οργανισμό Διαστήματος (ΕΟΔ-ESA). Βάσει των προτύπων αυτών, απαιτούνται νέες προσεγγίσεις και τεχνικές στο σχεδιασμό δορυφορικών δεκτών. Παράλληλα, η προσέγγιση Software Defined Radio (SDR) αποτελεί μια πολλά υποσχόμενη μεθοδολογία η οποία επιτρέπει την απαιτούμενη προσαρμοστικότητα και ευελιξία για την υποστήριξη πολλαπλών τύπων λειτουργίας και ρυθμών συμβόλων στους σύγχρονους δέκτες. Ο συγχρονισμός σε ένα δορυφορικό δέκτη (μονού φορέα) αποτελεί μια πολύπλοκη και απαιτητική διαδικασία που αφορά την εκτίμηση των παραμέτρων της μετάδοσης, οι οποίες και ανταποκρίνονται στον πραγματικό ρυθμό συμβόλων, στη συχνότητα και φάση του φορέα μετάδοσης καθώς και στη γνώση των ορίων των πλαισίων φυσικού επιπέδου. Οι μηχανισμοί συγχρονισμού αποτελούν σημαντικό, από άποψη κρισιμότητας και απαιτήσεων σε επεξεργαστική ισχύ, τμήμα των αποδιαμορφωτών, οι οποίοι σε περίπτωση λειτουργικής αποτυχίας οδηγούν στην απώλεια της αξιοπιστίας του δέκτη. Εξαιτίας της σπουδαιότητας των μηχανισμών αυτών, η αναζήτηση αποδοτικών και υλοποιήσιμων αλγορίθμων συγχρονισμού αποτελεί σημαντική παράμετρο στον σχεδιασμό συστημάτων δεκτών. Ένα σημαντικό πρόβλημα που αρχικά αντιμετώπισε η παρούσα διδακτορική διατριβή αφορά την ανάπτυξη βέλτιστης αρχιτεκτονικής διαχείρισης του σήματος εισόδου IF σε ένα δέκτη SDR μέσω κατάλληλης ψηφιακής επεξεργασίας των δειγμάτων εισόδου. Σκοπός της βαθμίδας είναι να υποβιβάσει το φάσμα του ψηφιακού σήματος εισόδου IF στη βασική ζώνη, υπολογίζοντας τις αντίστοιχες συνιστώσες του σήματος βασικής ζώνης. Περιορισμό στο πρόβλημα, αποτελεί η μέγιστη συχνότητα δειγματοληψίας του κυκλώματος ψηφιοποίησης. Η λύση που προτείνεται αντιμετωπίζει τις παραπάνω συνθήκες με μια νέα αρχιτεκτονική που βασίζεται σε δύο βαθμίδες μετατόπισης συχνότητας, μια σταθερής και μια προγραμματιζόμενης συχνότητας. Η προγραμματιζόμενη οδηγείται από την εκτίμηση του σφάλματος μετατόπισης συχνότητας που πραγματοποιείται σε επόμενο στάδιο επεξεργασίας του σήματος βασικής ζώνης. Το πλεονέκτημα της αρχιτεκτονικής αυτής, είναι η διπλάσια ακρίβεια στη ρύθμιση της συχνότητας σε σχέση με την κλασική προσέγγιση για δεδομένη συχνότητα δειγματοληψίας και αριθμό bits στον καταχωρητή συσσώρευσης φάσης του ταλαντωτή. Τέλος, ο παραπάνω υποβιβαστής προορίζεται για χρήση σε δέκτες SDR με χρήση μετατροπέων σήματος (ADC) περιορισμένης συχνότητας δειγματοληψίας. Στο πλαίσιο της παρούσας εργασίας, μελετήθηκε ο μηχανισμός ανάκτησης χρονισμού συμβόλου (Symbol Timing Recovery - STR) που υλοποιείται με τη χρήση κλειστού βρόχου δεύτερης τάξης και βασίζεται στο σήμα ενός ανιχνευτή σφάλματος χρονισμού (Timing Error Detector - TED). Τα θεμελιώδη χαρακτηριστικά του βρόχου, όπως ο χρόνος και η ποιότητα σύγκλισης, καθορίζονται από τις τιμές του κέρδους των δύο κλάδων του φίλτρου του βρόχου πρώτης τάξης τύπου P-I (Proportional-Integral) που αποτελεί μια ευρέως διαδεδομένη λύση για τηλεπικοινωνιακές εφαρμογές συγχρονισμού. Αφού περιγράφηκε και αναλύθηκε η γενικευμένη μεθοδολογία παραμετροποίησης του βρόχου, στη συνέχεια δόθηκε έμφαση σε βρόχους που αξιοποιούν τον ανιχνευτή Gardner. Τα χαρακτηριστικά ανεξαρτησίας του από τις τιμές των συμβόλων που χρησιμοποιεί καθώς και του παραμένοντος σφάλματος συχνότητας, τον καθιστούν μια αξιόπιστη λύση για τον συγχρονισμό συμβόλων πριν από το συγχρονισμό συχνότητας σε ψηφιακούς δέκτες. Κάνοντας χρήση της ανάλυσης αυτής και λόγω της υστέρησης των διαγραμμάτων πολλαπλών δακτυλίων τύπου M-APSK, ως προς την απόδοση του κλειστού βρόχου ανάκτησης χρονισμού συμβόλου, σε σχέση με τα διαγράμματα μονού δακτυλίου ίδιας μέσης ενέργειας, η διατριβή προτείνει μια παραλλαγή του τυπικού βρόχου για τη βελτίωση της συμπεριφοράς τους. Η αυξημένη διακύμανση στο σήμα εισόδου του ανιχνευτή λόγω της εναλλαγής των συμβόλων διαφορετικού πλάτους στην είσοδο του ανιχνευτή σφάλματος χρονισμού αποτελεί την κύρια αιτία για την αυξημένη διακύμανση κατά την παρακολούθηση του σφάλματος χρονισμού από τις δομές τέτοιων βρόχων. Η προσέγγιση που προτείνεται, βασίζεται στην εισαγωγή μιας υπομονάδας στον τυπικό βρόχο που προσαρμόζει τα πλάτη των συμβόλων όλων των δακτυλίων σε ένα δακτύλιο αναφοράς πριν την εισαγωγή τους στον ανιχνευτή σφάλματος χρονισμού. Επίσης κάνει χρήση του τοπικού ρολογιού του βρόχου με στόχο τη ρύθμιση του πλάτους συγκεκριμένων δειγμάτων του σήματος εισόδου και χωρίς να επηρεάζει τα πλάτη των συμβόλων που εισάγονται στο προσαρμοσμένο φίλτρο εξόδου. Η εφαρμογή της υπομονάδας έχει ως αποτέλεσμα τη μείωση του θορύβου κατά την παρακολούθηση του σφάλματος μετά την αρχική σύγκλιση του βρόχου, γεγονός που μεταφράζεται στη μείωση της τυπικής απόκλισης του σφάλματος εκτίμησης του χρονισμού σε σύγκριση με τον τυπικό βρόχο. Η απόδοση των βαθμίδων συγχρονισμού καθορίζεται συνήθως με βάση εσωτερικές παραμέτρους οι οποίες και επηρεάζονται σημαντικά από την αρχιτεκτονική του εκάστοτε μηχανισμού, την παράμετρο εκτίμησης καθώς και την κατάσταση λειτουργίας του μηχανισμού. Η διατριβή αξιοποιώντας την ύπαρξη πολλαπλών δακτυλίων στα διαγράμματα αστερισμού της μεθόδου διαμόρφωσης προτείνει ένα νέο ενιαίο μέγεθος εκτίμησης της απόδοσης των βαθμίδων συγχρονισμού σε δέκτες διαγραμμάτων πολλαπλών δακτυλίων M-APSK. Σημαντικό πλεονέκτημα του μέγεθος αποτελεί η αποκλειστική χρήση του σήματος εξόδου των βαθμίδων συγχρονισμού μέσω κατάλληλης επεξεργασίας (των παραγόμενων τιμών συμβόλων), παρέχοντας τη δυνατότητα στο μέγεθος να χρησιμοποιηθεί σε συνθήκες μετατόπισης συχνότητας/φάσης φορέα και/ή σφάλματος στο χρονισμό συμβόλου. Ένα άλλο πλεονέκτημα του παραπάνω μεγέθους σχετίζεται με το γεγονός ότι δεν είναι αναγκαία η γνώση των μεταδιδόμενων συμβόλων, σε αντίθεση με αντίστοιχα μεγέθη απόδοσης που χρησιμοποιούνται στην έξοδο των αποδιαμορφωτών, όπως το Error Vector Magnitude (EVM). Η μαθηματική ανάλυση της μέσης τιμής του μεγέθους σε συνθήκες προσθετικού λευκού προσθετικού θορύβου (AWGN) που παρουσιάζεται στη διατριβή αυτή αφορά τόσο την περίπτωση όπου ο δέκτης γνωρίζει τον δακτύλιο προέλευσης των λαμβανομένων συμβόλων, όσο και την περίπτωση όπου ο δέκτης αγνοεί τον δακτύλιο προέλευσης των λαμβανομένων συμβόλων και υπολογίζει το μέγεθος σύμφωνα με τον πλησιέστερο σε αυτά δακτύλιο. Το δεύτερο από τα παραπάνω σενάρια αφορά ρεαλιστικά συστήματα δεκτών όπου η πληροφορία του δακτυλίου προέλευσης των συμβόλων λήψης δεν είναι διαθέσιμη. Και στις δύο παραπάνω περιπτώσεις, αποδεικνύεται μια σταθερή σχέση του προτεινόμενου μεγέθους με το λόγο των ισχύων συμβόλου και θορύβου AWGN (Es/No). Βάσει των παραπάνω χαρακτηριστικών, το προτεινόμενο μέγεθος είναι σε θέση να αξιοποιηθεί για την εκτίμηση των συνθηκών στο κανάλι υπό συνθήκες λευκού Gaussian θορύβου μέσω επεξεργασίας του σήματος εξόδου από τον βρόχο STR ο οποίος αποτελεί συνήθως και τον πρώτο μηχανισμό συγχρονισμού σε ψηφιακούς δέκτες δορυφορικών επικοινωνιών. Αξίζει να σημειωθεί ότι η εκτίμηση των συνθηκών αυτών είναι εφικτή ακόμα και υπό συνθήκες σημαντικού παραμένοντος σφάλματος στη συχνότητα του φορέα. Η σπουδαιότητα της εκτίμησης αυτής έγκειται στο γεγονός ότι μπορεί να αξιοποιηθεί από τις ακόλουθες βαθμίδες συγχρονισμού (συχνότητας φορέα και φάσης) για την κατάλληλη προσαρμογή και επιτάχυνση των λειτουργιών τους. Μία δεύτερη μορφή αξιοποίησης του μεγέθους αποτελεί και η εκτίμηση-διόρθωση μεγάλων αποκλίσεων στη συχνότητα του φορέα κάνοντας χρήση προς επεξεργασία παραγόμενων, από το συγκεκριμένο βρόχο, σημάτων. Τα σήματα αυτά σχετίζονται με την είσοδο και την έξοδο του προσαρμοσμένου φίλτρου του βρόχου STR. Ο έλεγχος της απόκλισης στη συχνότητα του φορέα στο συγκεκριμένο σημείο επεξεργασίας των ψηφιακών δεκτών κάτω από συγκεκριμένα όρια, είναι ιδιαίτερα κρίσιμος καθώς επηρεάζει σημαντικά την απόδοση και αποτελεσματικότητα των ακόλουθων βαθμίδων συγχρονισμού. Στο τελικό στάδιό της, η διατριβή αναλύει και παρουσιάζει την υλοποίηση ενός πλήρους αποδιαμορφωτή SDR τεχνολογίας DVB-S2 σε πλατφόρμα επαναπρογραμματιζόμενης λογικής που συνδυάζει κυκλώματα υλικού και λογισμικού (FPGA, DSP). O αποδιαμορφωτής υποστηρίζει τα διαγράμματα μονού (QPSK/8PSK), διπλού (16APSK) και τριπλού (32APSK) δακτυλίου, ενώ αποτελεί τμήμα ενός συνολικού δέκτη DVB-S2 που υλοποιεί όλες τις λειτουργίες, από τη διαχείριση του σήματος εισόδου ΙF μέχρι την προώθηση της ανακτώμενης ψηφιακής πληροφορίας σε τοπικό δίκτυο GbE-LAN. Στην υλοποίηση του αποδιαμορφωτή περιλαμβάνεται η υλοποίηση σε κύκλωμα FPGA του προτεινόμενου υποβιβαστή συχνότητας IF, η υλοποίηση σε DSP του βρόχου STR (βάσει του ανιχνευτή Gardner) και όλων των υπόλοιπων μηχανισμών συγχρονισμού που είναι απαραίτητοι για τη σωστή αποδιαμόρφωση του σήματος εισόδου. Οι μηχανισμοί αυτοί είναι: συγχρονισμός πλαισίου, συγχρονισμός συχνότητας και φάσης φορέα καθώς και κανονικοποίηση πλάτους πριν την αντιστοίχιση των bits. Επίσης δίνονται πληροφορίες για την υλοποίηση των μηχανισμών αντιστοίχισης (Demapping), διόρθωσης σφαλμάτων (FEC - LDPC/BCH) καθώς και του μηχανισμού διαχείρισης και προώθησης (BBFRAME Processing) της ανακτώμενης πληροφορίας προς τη διεπαφή τοπικού δικτύου του δέκτη DVB-S2. / The objective of this thesis is the analysis and study of the synchronization mechanisms performed by digital satellite terminal receivers when multiple ring constellation diagrams are used. The aim of this thesis is to develop new synchronization techniques that exhibit improved performance and to also propose new methods and ways for evaluating the effectiveness of such receiver submodules. The new trends in the field of digital communications systems and, especially, in modulation and error coding techniques, along with the increasing demand for more effective and interactive applications and services through limited satellite links, have initiated the development of new satellite communications standards. The newest standard is DVB-S2, by the European Space Agency (ESA), in which modern and up-to-date techniques for the design of satellite terminal receiver are required. Meanwhile, the Software Defined Radio (SDR) technology comprises a promising implementation approach as it incorporates the necessary flexibility and versatility for supporting various functionalities and rates into modern receiver structures. Synchronization functions of satellite receivers are complicated and demanding procedures that are related to the estimation of transmission parameters, which correspond to the nominal symbol rate, carrier frequency, phase and to the boundaries of the physical layer frames. These functions determine the complexity and performance of receiver realizations. Thus developing more efficient and simple, in terms of implementation complexity, algorithms and mechanisms is a key objective in such processing platforms. A significant problem that was encountered during the research for the present thesis, was the design and implementation of an efficient digital IF down-converter architecture that is able to manipulate the input IF signal of an SDR receiver through proper processing of its digital input sample stream. The objective of this unit is the shifting of the IF input signal to baseband and the generation of the corresponding baseband I, Q signals. A usual limitation in such realizations is the maximum sampling frequency of front-end ADC circuits. The presented solution addresses this constraint with an architecture that is based on two cascaded units of frequency down-conversion, one with fixed and one with programmable frequency. The programmable unit is driven by the frequency offset estimations of a following baseband processing stage. The advantage of this architecture is the double precision that is achieved compared to the typical approach and for a given sampling frequency. It is worth mentioning that the frequency converter is intended for use in SDR receivers utilizing ADC circuits of moderate sampling frequency. Additionally, in the framework of this thesis, the Symbol Timing Recovery (STR) mechanism based on a second order feedback loop driven by the signal of a timing error detector (TED), was studied and analyzed. The fundamental characteristics of such a control loop, mainly the duration and quality of the initial acquisition are defined through the gain value of the two paths included into the first order loop filter (Proportional-Integral, P-I). This structure comprises a usual approach for communications applications. Conforming to this general analysis for the configuration and the design of the feedback loop, the thesis focuses on the feedback loop incorporating the Non-Data-Aided (NDA) Gardner TED. Using the above analysis and due to the fact that multiple ring constellation diagrams exhibit insufficient performance in such closed loops in comparison to the single ring counterparts of the same mean energy, this thesis proposes a modification of the typical loop deploying the Gardner TED that improves its performance. The increased variance of the input signal of the TED that stems from the changes of symbols with variable magnitude comprises the main reason for the increased variance during the tracking of the timing error in such loop structures. The proposed approach is based on the insertion of a subunit inside the loop structure that adjusts the symbol magnitudes of all rings to a reference magnitude before they are fed into the Gardner TED logic. The above subunit makes use of the internally generated clock of the loop in order to control the magnitude of specific signal samples and does not affect the sample stream at the matched filter input. The application of the specific subunit has the advantage of minimizing the noise during the tracking operation of the loop, which leads to the decrease of the standard deviation of the estimation error when compared to the typical loop structure. The performance of synchronization mechanisms is usually evaluated based on internal parameters that are strongly related to the utilized architecture, the estimated parameter and the operational status of the specific mechanism. The present thesis exploits the use of multiple ring constellation diagrams in modulation process and proposes a generic and new `figure of merit' that is able to determine the performance of various synchronization mechanisms that are incorporated into multiple ring constellation (M-APSK) receivers. A significant advantage of this metric is that it solely based on the processing of the signal at the mechanism's output (extracted symbol values) which enables the utilization of this metric in the presence of frequency, phase and symbol rate offset errors. Another advantage of the proposed metric is that it does not require any knowledge on the transmitted symbols, in contrast to other widely used performance metrics that are applied at the demodulator output, such as the Error Vector Magnitude (EVM) e.t.c. The mathematical analysis of the mean value of the metric under additive white Gaussian noise (AWGN) that is exhibited in this document, includes the theoretical and practical cases. In the first, the receiver is aware of the ring derivation of received symbols, whereas in the second case this information is absent and the receiver determines the metric according to the nearest ring for each symbol. The second case corresponds to realistic receiver realizations. As is shown, in both cases there is a fixed relation between the proposed metric and the commonly used performance metric ratio Es/No for AWGN channels. According to the characteristics described above, the proposed metric can be utilized for the estimation of channel condition under additive white Gaussian noise. This is accomplished through the processing of the STR output signal (symbol values) which usually comprises the first synchronization mechanism in digital satellite terminal receivers. It is worth mentioning that the channel estimation is feasible even under significant carrier frequency offset errors. The significance of the above process is related to the fact that this estimation can be exploited by the following synchronization subunits (of carrier frequency and phase) of the receiver in order to properly adjust and make their operations faster. A second application of the proposed metric is the recovery of large frequency offset errors by processing the signal at the input and the output of the matched filter of the previously mentioned STR structure. The control of frequency offset errors at such point of the receiver processing chain under specific limits, is critical as it strongly affects the performance and efficiency of the following synchronization mechanisms. Finally, this thesis analyzes and presents the implementation of a complete SDR IF demodulator that is compliant to DVB-S2 technology and is based on a reconfigurable hardware platform. This platform incorporates hardware (FPGA) and software (DSP) circuits in a unified environment. The IF demodulator supports single (QPSK/8PSK), two (16APSK) and three (32APSK) ring constellations and comprises a significant part of a full receiver implementation that includes all the necessary functions ranging from the manipulation of the input IF signal to the forwarding of the recovered user information to a Gigabit Ethernet (GbE) LAN. In addition, the IF demodulator implementation includes the hardware realization of the IF digital down-converter into an FPGA device and the software realization of the remaining synchronization procedures starting from the STR into the available DSP processors of the reconfigurable platform. The other necessary procedures for the proper demodulation of the input signal, are: frame synchronization, carrier frequency/phase recovery and amplitude normalization. Furthermore, information is also given on the implementation of the corresponding demapping, error correction and LAN interfacing procedures that are performed in the following processing stages of the DVB-S2 receiver.

In this project, two tests were performed. On the first test, Mininet-WiFi was used to simulate a Software Defined Network to demonstrate Mininet-WiFi’ s ability to be used as the Software Defined Network emulator which can also be integrated to the existing network using a Network Virtualized Function (NVF). A typical organization’s computer network was simulated which consisted of a website hosted on the LAMP (Linux, Apache, MySQL, PHP) virtual machine, and an F5 application delivery controller (ADC) which provided load balancing of requests sent to the web applications. A website page request was sent from the virtual stations inside Mininet-WiFi. The request was received by the application delivery controller, which then used round robin technique to send the request to one of the web servers on the LAMP virtual machine. The web server then returned the requested website to the requesting virtual stations using the simulated virtual network. The significance of these results is that it presents Mininet-WiFi as an emulator, which can be integrated into a real programmable networking environment offering a portable, cost effective and easily deployable testing network, which can be run on a single computer. These results are also beneficial to modern network deployments as the live network devices can also communicate with the testing environment for the data center, cloud and mobile provides. On the second test, a Software Defined Network was created in Mininet using python script. An external interface was added to enable communication with the network outside of Mininet. The amazon web services elastic computing cloud was used to host an OpenDaylight controller. This controller is used as a control plane device for the virtual switch within Mininet. In order to test the network, a webserver hosted on the Emulated Virtual Environment – Next Generation (EVENG) software is connected to Mininet. EVE-NG is the Emulated Virtual Environment for networking. It provides tools to be able to model virtual devices and interconnect them with other virtual or physical devices. The OpenDaylight controller was able to create the flows to facilitate communication between the hosts in Mininet and the webserver in the real-life network. / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)

L'informatique en nuage (Cloud Computing) a émergé comme un nouveau paradigme pour offrir des ressources informatiques à la demande et pour externaliser des infrastructures logicielles et matérielles. Le Cloud Computing est rapidement et fondamentalement en train de révolutionner la façon dont les services informatiques sont mis à disposition et gérés. Ces services peuvent être demandés à partir d’un ou plusieurs fournisseurs de Cloud d’où le besoin de la mise en réseau entre les composants des services informatiques distribués dans des emplacements géographiquement répartis. Les utilisateurs du Cloud veulent aussi déployer et instancier facilement leurs ressources entre les différentes plateformes hétérogènes de Cloud Computing. Les fournisseurs de Cloud assurent la mise à disposition des ressources de calcul sous forme des machines virtuelles à leurs utilisateurs. Par contre, ces clients veulent aussi la mise en réseau entre leurs ressources virtuelles. En plus, ils veulent non seulement contrôler et gérer leurs applications, mais aussi contrôler la connectivité réseau et déployer des fonctions et des services de réseaux complexes dans leurs infrastructures virtuelles dédiées. Les besoins des utilisateurs avaient évolué au-delà d'avoir une simple machine virtuelle à l'acquisition de ressources et de services virtuels complexes, flexibles, élastiques et intelligents. L'objectif de cette thèse est de permettre le placement et l’instanciation des ressources complexes dans des infrastructures de Cloud distribués tout en permettant aux utilisateurs le contrôle et la gestion de leurs ressources. En plus, notre objectif est d'assurer la convergence entre les services de cloud et de réseau. Pour atteindre cela, nous proposons des algorithmes de mapping d’infrastructures virtuelles dans les centres de données et dans le réseau tout en respectant les exigences des utilisateurs. Avec l'apparition du Cloud Computing, les réseaux traditionnels sont étendus et renforcés avec des réseaux logiciels reposant sur la virtualisation des ressources et des fonctions réseaux. En plus, le nouveau paradigme d'architecture réseau (Software Defined Networks) est particulièrement pertinent car il vise à offrir la programmation du réseau et à découpler, dans un équipement réseau, la partie plan de données de la partie plan de contrôle. Dans ce contexte, la première partie propose des algorithmes optimaux (exacts) et heuristiques de placement pour trouver le meilleur mapping entre les demandes des utilisateurs et les infrastructures sous-jacentes, tout en respectant les exigences exprimées dans les demandes. Cela inclut des contraintes de localisation permettant de placer une partie des ressources virtuelles dans le même nœud physique. Ces contraintes assurent aussi le placement des ressources dans des nœuds distincts. Les algorithmes proposés assurent le placement simultané des nœuds et des liens virtuels sur l’infrastructure physique. Nous avons proposé aussi un algorithme heuristique afin d’accélérer le temps de résolution et de réduire la complexité du problème. L'approche proposée se base sur la technique de décomposition des graphes et la technique de couplage des graphes bipartis. Dans la troisième partie, nous proposons un cadriciel open source (framework) permettant d’assurer la mise en réseau dynamique entre des ressources Cloud distribués et l’instanciation des fonctions réseau dans l’infrastructure virtuelle de l’utilisateur. Ce cadriciel permettra de déployer et d’activer les composants réseaux afin de mettre en place les demandes des utilisateurs. Cette solution se base sur un gestionnaire des ressources réseaux "Cloud Network Gateway Manager" et des passerelles logicielles permettant d’établir la connectivité dynamique et à la demande entre des ressources cloud et réseau. Le CNG-Manager offre le contrôle de la partie réseau et prend en charge le déploiement des fonctions réseau nécessaires dans l'infrastructure virtuelle des utilisateurs / Cloud computing emerged as a new paradigm for on-demand provisioning of IT resources and for infrastructure externalization and is rapidly and fundamentally revolutionizing the way IT is delivered and managed. The resulting incremental Cloud adoption is fostering to some extent cloud providers cooperation and increasing the needs of tenants and the complexity of their demands. Tenants need to network their distributed and geographically spread cloud resources and services. They also want to easily accomplish their deployments and instantiations across heterogeneous cloud platforms. Traditional cloud providers focus on compute resources provisioning and offer mostly virtual machines to tenants and cloud services consumers who actually expect full-fledged (complete) networking of their virtual and dedicated resources. They not only want to control and manage their applications but also control connectivity to easily deploy complex network functions and services in their dedicated virtual infrastructures. The needs of users are thus growing beyond the simple provisioning of virtual machines to the acquisition of complex, flexible, elastic and intelligent virtual resources and services. The goal of this thesis is to enable the provisioning and instantiation of this type of more complex resources while empowering tenants with control and management capabilities and to enable the convergence of cloud and network services. To reach these goals, the thesis proposes mapping algorithms for optimized in-data center and in-network resources hosting according to the tenants' virtual infrastructures requests. In parallel to the apparition of cloud services, traditional networks are being extended and enhanced with software networks relying on the virtualization of network resources and functions especially through network resources and functions virtualization. Software Defined Networks are especially relevant as they decouple network control and data forwarding and provide the needed network programmability and system and network management capabilities. In such a context, the first part proposes optimal (exact) and heuristic placement algorithms to find the best mapping between the tenants' requests and the hosting infrastructures while respecting the objectives expressed in the demands. This includes localization constraints to place some of the virtual resources and services in the same host and to distribute other resources in distinct hosts. The proposed algorithms achieve simultaneous node (host) and link (connection) mappings. A heuristic algorithm is proposed to address the poor scalability and high complexity of the exact solution(s). The heuristic scales much better and is several orders of magnitude more efficient in terms of convergence time towards near optimal and optimal solutions. This is achieved by reducing complexity of the mapping process using topological patterns to map virtual graph requests to physical graphs representing respectively the tenants' requests and the providers' physical infrastructures. The proposed approach relies on graph decomposition into topology patterns and bipartite graphs matching techniques. The third part propose an open source Cloud Networking framework to achieve cloud and network resources provisioning and instantiation in order to respectively host and activate the tenants' virtual resources and services. This framework enables and facilitates dynamic networking of distributed cloud services and applications. This solution relies on a Cloud Network Gateway Manager and gateways to establish dynamic connectivity between cloud and network resources. The CNG-Manager provides the application networking control and supports the deployment of the needed underlying network functions in the tenant desired infrastructure (or slice since the physical infrastructure is shared by multiple tenants with each tenant receiving a dedicated and isolated portion/share of the physical resources)

Software Defined Networking (SDN) has become increasingly popular in combination with Network Function Virtualization (NFV). SDN is a way to make a network more programmable and dynamic. However, in order to create a homogeneous network using this concept, legacy equipment will have to be substituted by SDN equipment, which is costly. To close the gap between the legacy world and SDN, we introduce the concept of a legacy Network Management System (NMS) that is connected to an SDN controller to perform service provisioning. This way, the NMS is capable of configuring both legacy as well as SDN networks to provide customers with the services that they have ordered, while still allowing for new SDN features in the SDN domain of the network. The main service we wish to provide using SDN is Service Function Chaining (SFC). Service provisioning consists of dynamically constructing a path through the ordered network services, in this case Virtual Network Functions (VNFs). This thesis focuses on the SDN controller and its interaction with the NMS. This project aims at configuring OpenFlow rules in the network using an SDN controller to perform SFC. Moreover, the focus will be on how to represent an SDN element and a service function chain in the legacy network NMS. The thesis also contains a discussion on what information should be exchanged between the management software and the controller. The management software used is called BECS, a system developed by Packetfront Software. Integrating SDN in BECS is done by creating a proof of concept, containing a full environment from the low level network elements to the NMS. By using a bottom-up approach for creating this proof of concept, the information that BECS is required to send to the SDN controller can be identified before designing and implementing the connection between these two entities. When sending the information, the NMS should be able to receive acknowledgement of successful information exchange or an error. However, when the proof of concept was created a problem arose on how to test and troubleshoot it. For this reason, a web Graphical User Interface (GUI) was created. This GUI shows the number of packets that have gone through a VNF. Because it is possible to see how many packets go through a VNF, one can see where a network issue occurs. The subsequent analysis investigates the impact of making such a GUI available for a network administrator and finds that the part of the network where the configuration error occurs can be narrowed down significantly. / Software Defined Networking (SDN) har blivit mer och mer populärt i kombination med Network Function Virtualization (NFV). SDN är en sätt för att göra ett nätverk mer programmerbart och dynamiskt. För att skapa ett homogent nätverk med detta koncept, behöver man dock ersätta traditionell utrustning med SDN utrustning som är dyr. För att stänga gapet mellan traditionella nätverk och SDN-världen, introducerar vi ett koncept med ett traditionell Network Management System (NMS) som är anslutet till en SDN-styrenhet för att utföra tjänsteprovisionering. På detta sätt kan NMS:et konfigurera både traditionella och SDN-nätverk, samt provisionera tjänster för kunderna medan nya SDN-funktioner möjliggörs i SDN-delen av nätverket. Den huvudsakliga tjänsten som vi vill lansera genom SDN är Service Function Chaining (SFC). Tjänsteprovisionering består av att konstruera en väg genom beställda tjänster, i detta fall Virtual Network Functions (VNFs). Detta examensarbete fokuserar huvusakligen på SDN-styrenheten och dess interaktion med NMS:et. Projektet syftar till att konfigurera OpenFlow regler i SDN-styrenheten för att utföra SFC. Dessutom fokuserar arbetet på hur man kan representera SDN-element och SFCs i ett traditionellt NMS. Vidare diskuteras vilken information som ska utbytas mellan NMS:et och SDNstyrenheten. NMS:et som ska vara användas är BECS, ett system utvecklat av Packetfront Software. Uppgiften löses genom att skapa ett proof of concept, som innehåller ett komplett system med alla komponenter från nätverkselement till NMS:et. Genom att använda en bottom-up-strategi för detta proof of concept kan informationen som BECS måste skicka till SDN styrenheten indentifieras, innan design och implementation av förbindelsen mellan enheterna kan utföras. När informationen är skickad ska NMS:et kunna hämta information om huruvida styrenheten fick informationen utan fel. Dock uppstår ett problem gällande hur man testar och felsöker detta proof of concept. Av denna anledning skapades ett web Graphical User Interface (GUI). Användargränssnittet visar antalet paket som går genom varje VNF, samt var i nätverket fel uppstår. Analysen undersöker hur stor effekten är för en nätverkadministrator och visar att området där fel kan uppstå begränsas avsevärt.

Internet of Things is expanding to the areas such as healthcare, home management, industrial, agriculture, and becoming pervasive in our life, resulting in improved efficiency, accuracy and economic benefits. Smart sensors with embedded interfacing integrated circuits (ICs) are important enablers, hence, variety of smart sensors are required. However, each type of sensor requires specific interfacing chips, which divides the huge market of sensors’ interface chips into lots of niche markets, resulting in high develop cost and long time-to-market period for each type. Software defined sensor is regarded as a promising solution, which is expected to use a flexible interface platform to cover different sensors, deliver specificity through software programming, and integrate easily into the Internet of Things. In this work, research is carried out on the design and implementations of ultra low power analog interface circuits toward software defined sensors for healthcare services based on Internet of Things.    This thesis first explores architectures and circuit techniques for energy-efficient and flexible analog to digital conversion. A time-spreading digital calibration, to calibrate the errors due to finite gain and capacitor mismatch in multi-bit/stage pipelined converters, is developed with short convergence time. The effectiveness of the proposed technique is demonstrated with intensive simulations. Two novel circuit level techniques, which can be combined with digital calibration techniques to further improve the energy efficiency of the converters, are also presented. One is the Common-Mode-Sensing-and-Input-Interchanging (CSII) operational-transconductance-amplifier (OTA) sharing technique to enable eliminating potential memory effects. The other is a workload-balanced multiplying digital-to-analog converter (MDAC) architecture to improve the settling efficiency of a high linear multi-bit stage. Two prototype converters have been designed and fabricated in 0.13 μm CMOS technology. The first one is a 14 bit 50 MS/s digital calibrated pipelined analog to digital converter that employs the workload-balanced MDAC architecture and time-spreading digital calibration technique to achieve improved power-linearity tradeoff. The second one is a 1.2 V 12 bit 5~45 MS/s speed and power-scalable ADC incorporating the CSII OTA-sharing technique, sample-and-hold-amplifier-free topology and adjustable current bias of the building blocks to minimize the power consumption. The detailed measurement results of both converters are reported and deliver the experimental verification of the proposed techniques.     Secondly, this research investigates ultra-low-power analog front-end circuits providing programmability and being suitable for different types of sensors. A pulse-width- -modulation-based architecture with a folded reference is proposed and proven in a 0.18 μm technology to achieve high sensitivity and enlarged dynamic range when sensing the weak current signals. A 8-channel bio-electric sensing front-end, fabricated in a 0.35 μm CMOS technology is also presented that achieves an input impedance of 1 GΩ, input referred noise of 0.97 Vrms and common mode rejection ratio of 114 dB. With the programmable gain and cut-off frequency, the front-end can be configured to monitor for long-term a variety of bio-electric signals, such as electrooculogram (EOG), electromyogram (EMG), electroencephalogram (EEG) and electrocardiogram (ECG) signals. The proposed front-end is integrated with dry electrodes, a microprocessor and wireless link to build a battery powered E-patch for long-term and continuous monitoring. In-vivo test results with dry electrodes in the field trials of sitting, standing, walking and running slowly, show that the quality of ECG signal sensed by the E-patch satisfies the requirements for preventive cardiac care.    Finally, a wireless multimodal bio-electric sensor system is presented. Enabled by a customized flexible mixed-signal system on chip (SoC), this bio-electric sensor system is able to be configured for ECG/EMG/EEG recording, bio-impedance sensing, weak current stimulation, and other promising functions with biofeedback. The customized SoC, fabricated in a 0.18 μm CMOS technology, integrates a tunable analog front-end, a 10 bit ADC, a 14 bit sigma-delta digital to current converter, a 12 bit digital to voltage converter, a digital accelerator for wavelet transformation and data compression, and a serial communication protocol. Measurement results indicate that the SoC could support the versatile bio-electric sensor to operate in various applications according to specific requirements. / <p>QC 20151221</p>