Nowadays, the digital terrestrial television (DTT) market is characterized by the high capacity needed for high definition TV services. There is a need for an efficient use of the broadcast spectrum, which requires new technologies to guarantee increased capacities. Non-Uniform Constellations (NUC) arise as one of the most innovative techniques to approach those requirements. NUCs reduce the gap between uniform Gray-labelled Quadrature Amplitude Modulation (QAM) constellations and the theoretical unconstrained Shannon limit. With these constellations, symbols are optimized in both in-phase (I) and quadrature (Q) components by means of signal geometrical shaping, considering a certain signal-to-noise ratio (SNR) and channel model. There are two types of NUC, one-dimensional and two-dimensional NUCs (1D-NUC and 2D-NUC, respectively). 1D-NUCs maintain the squared shape from QAM, but relaxing the distribution between constellation symbols in a single component, with non-uniform distance between them. These constellations provide better SNR performance than QAM, without any demapping complexity increase. 2D-NUCs also relax the square shape constraint, allowing to optimize the symbol positions in both dimensions, thus achieving higher capacity gains and lower SNR requirements. However, the use of 2D-NUCs implies a higher demapping complexity, since a 2D-demapper is needed, i.e. I and Q components cannot be separated. In this dissertation, NUCs are analyzed from both transmit and receive point of views, using either single-input single-output (SISO) or multiple-input multiple-output (MIMO) antenna configurations. In SISO transmissions, 1D-NUCs and 2D-NUCs are optimized for a wide range of SNRs and different constellation orders. The optimization of rotated 2D-NUCs is also investigated. Even though the demapping complexity is not increased, the SNR gain of these constellations is not significant. The highest rotation gain is obtained for low-order constellations and high SNRs. However, with multi-RF techniques, the SNR gain is drastically increased, since I and Q components are transmitted in different RF channels. In this thesis, multi-RF gains of NUCs with and without rotation are provided for some representative scenarios. At the receiver, two different implementation bottlenecks are explored. First, the demapping complexity of all considered constellations is analyzed. Afterwards, two complexity reduction algorithms for 2D-NUCs are proposed. Both algorithms drastically reduce the number of distances to compute. Moreover, both are finally combined in a single demapper. Quantization of NUCs is also explored in this dissertation, since LLR values and I/Q components are modified when using these constellations, compared to traditional QAM constellations. A new algorithm that is based on the optimization of the quantizer levels for a particular constellation is proposed. The use of NUCs in multi-antenna communications is also investigated. It includes the optimization in one or two antennas, the use of power imbalance, the cross-polar discrimination (XPD) between receive antennas, or the use of different demappers. Assuming different values for the parameters evaluated, new Multi-Antenna Non-Uniform Constellations (MA-NUC) are obtained by means of a particularized re-optimization process, specific for MIMO. At the receiver, an extended demapping complexity analysis is performed, where it is shown that the use of 2D-NUCs in MIMO extremely increases the demapping complexity. As an alternative, an efficient solution for 2D-NUCs and MIMO systems based on Soft-Fixed Sphere Decoding (SFSD) is proposed. The main drawback is that SFSD demappers do not work with 2D-NUCs, since they perform a Successive Interference Cancellation (SIC) step that needs to be performed in separated I and Q components. The proposed method quantifies the closest symbol using Voronoi regions and allows SFSD demappers to work. / Hoy en día, el mercado de la televisión digital terrestre (TDT) está caracterizado por la alta capacidad requerida para transmitir servicios de televisión de alta definición y el espectro disponible. Es necesario por tanto un uso eficiente del espectro radioeléctrico, el cual requiere nuevas tecnologías para garantizar mayores capacidades. Las constelaciones no-uniformes (NUC) emergen como una de las técnicas más innovadoras para abordar tales requerimientos. Las NUC reducen el espacio existente entre las constelaciones uniformes QAM y el límite teórico de Shannon. Con estas constelaciones, los símbolos se optimizan en ambas componentes fase (I) y cuadratura (Q) mediante técnicas geométricas de modelado de la señal, considerando un nivel señal a ruido (SNR) concreto y un modelo de canal específico. Hay dos tipos de NUC, unidimensionales y bidimensionales (1D-NUC y 2D-NUC, respectivamente). Las 1D-NUC mantienen la forma cuadrada de las QAM, pero permiten cambiar la distribución entre los símbolos en una componente concreta, teniendo una distancia no uniforme entre ellos. Estas constelaciones proporcionan un mejor rendimiento SNR que QAM, sin ningún incremento en la complejidad en el demapper. Las 2D-NUC también permiten cambiar la forma cuadrada de la constelación, permitiendo optimizar los símbolos en ambas dimensiones y por tanto obteniendo mayores ganancias en capacidad y menores requerimientos en SNR. Sin embargo, el uso de 2D-NUCs implica una mayor complejidad en el receptor. En esta tesis se analizan las NUC desde el punto de vista tanto de transmisión como de recepción, utilizando bien configuraciones con una antena (SISO) o con múltiples antenas (MIMO). En transmisiones SISO, se han optimizado 1D-NUCs para un rango amplio de distintas SNR y varios órdenes de constelación. También se ha investigado la optimización de 2D-NUCs rotadas. Aunque la complejidad no aumenta, la ganancia SNR de estas constelaciones no es significativa. La mayor ganancia por rotación se obtiene para bajos órdenes de constelación y altas SNR. Sin embargo, utilizando técnicas multi-RF, la ganancia aumenta drásticamente puesto que las componentes I y Q se transmiten en distintos canales RF. En esta tesis, se han estudiado varias ganancias multi-RF representativas de las NUC, con o sin rotación. En el receptor, se han identificado dos cuellos de botella diferentes en la implementación. Primero, se ha analizado la complejidad en el receptor para todas las constelaciones consideradas y, posteriormente, se proponen dos algoritmos para reducir la complejidad con 2D-NUCs. Además, los dos pueden combinarse en un único demapper. También se ha explorado la cuantización de estas constelaciones, ya que tanto los valores LLR como las componentes I/Q se ven modificados, comparando con constelaciones QAM tradicionales. Además, se ha propuesto un algoritmo que se basa en la optimización para diferentes niveles de cuantización, para una NUC concreta. Igualmente, se ha investigado en detalle el uso de NUCs en MIMO. Se ha incluido la optimización en una sola o en dos antenas, el uso de un desbalance de potencia, factores de discriminación entre antenas receptoras (XPD), o el uso de distintos demappers. Asumiendo distintos valores, se han obtenido nuevas constelaciones multi-antena (MA-NUC) gracias a un nuevo proceso de re-optimización específico para MIMO. En el receptor, se ha extendido el análisis de complejidad en el demapper, la cual se incrementa enormemente con el uso de 2D-NUCs y sistemas MIMO. Como alternativa, se propone una solución basada en el algoritmo Soft-Fixed Sphere Decoding (SFSD). El principal problema es que estos demappers no funcionan con 2D-NUCs, puesto que necesitan de un paso adicional en el que las componentes I y Q necesitan separarse. El método propuesto cuantifica el símbolo más cercano utilizando las regiones de Voronoi, permitiendo el uso de este tipo de receptor. / Actualment, el mercat de la televisió digital terrestre (TDT) està caracteritzat per l'alta capacitat requerida per a transmetre servicis de televisió d'alta definició i l'espectre disponible. És necessari per tant un ús eficient de l'espectre radioelèctric, el qual requereix noves tecnologies per a garantir majors capacitats i millors servicis. Les constel·lacions no-uniformes (NUC) emergeixen com una de les tècniques més innovadores en els sistemes de televisió de següent generació per a abordar tals requeriments. Les NUC redueixen l'espai existent entre les constel·lacions uniformes QAM i el límit teòric de Shannon. Amb estes constel·lacions, els símbols s'optimitzen en ambdós components fase (I) i quadratura (Q) per mitjà de tècniques geomètriques de modelatge del senyal, considerant un nivell senyal a soroll (SNR) concret i un model de canal específic. Hi ha dos tipus de NUC, unidimensionals i bidimensionals (1D-NUC i 2D-NUC, respectivament). 1D-NUCs mantenen la forma quadrada de les QAM, però permet canviar la distribució entre els símbols en una component concreta, tenint una distància no uniforme entre ells. Estes constel·lacions proporcionen un millor rendiment SNR que QAM, sense cap increment en la complexitat al demapper. 2D-NUC també canvien la forma quadrada de la constel·lació, permetent optimitzar els símbols en ambdós dimensions i per tant obtenint majors guanys en capacitat i menors requeriments en SNR. No obstant això, l'ús de 2D-NUCs implica una major complexitat en el receptor, ja que es necessita un demapper 2D, on les components I i Q no poden ser separades. En esta tesi s'analitzen les NUC des del punt de vista tant de transmissió com de recepció, utilitzant bé configuracions amb una antena (SISO) o amb múltiples antenes (MIMO). En transmissions SISO, s'han optimitzat 1D-NUCs, per a un rang ampli de distintes SNR i diferents ordes de constel·lació. També s'ha investigat l'optimització de 2D-NUCs rotades. Encara que la complexitat no augmenta, el guany SNR d'estes constel·lacions no és significativa. El major guany per rotació s'obté per a baixos ordes de constel·lació i altes SNR. No obstant això, utilitzant tècniques multi-RF, el guany augmenta dràsticament ja que les components I i Q es transmeten en distints canals RF. En esta tesi, s'ha estudiat el guany multi-RF de les NUC, amb o sense rotació. En el receptor, s'han identificat dos colls de botella diferents en la implementació. Primer, s'ha analitzat la complexitat en el receptor per a totes les constel·lacions considerades i, posteriorment, es proposen dos algoritmes per a reduir la complexitat amb 2D-NUCs. Ambdós algoritmes redueixen dràsticament el nombre de distàncies. A més, els dos poden combinar-se en un únic demapper. També s'ha explorat la quantització d'estes constel·lacions, ja que tant els valors LLR com les components I/Q es veuen modificats, comparant amb constel·lacions QAM tradicionals. A més, s'ha proposat un algoritme que es basa en l'optimització per a diferents nivells de quantització, per a una NUC concreta. Igualment, s'ha investigat en detall l'ús de NUCs en MIMO. S'ha inclòs l'optimització en una sola o en dos antenes, l'ús d'un desbalanç de potència, factors de discriminació entre antenes receptores (XPD), o l'ús de distints demappers. Assumint distints valors, s'han obtingut noves constel·lacions multi-antena (MA-NUC) gràcies a un nou procés de re-optimització específic per a MIMO. En el receptor, s'ha modificat l'anàlisi de complexitat al demapper, la qual s'incrementa enormement amb l'ús de 2D-NUCs i sistemes MIMO. Com a alternativa, es proposa una solució basada en l'algoritme Soft-Fixed Sphere Decoding (SFSD) . El principal problema és que estos demappers no funcionen amb 2D-NUCs, ja que necessiten d'un pas addicional en què les components I i Q necessiten separar-se. El mètode proposat quantifica el símbol més pròxim utilitzan / Fuentes Muela, M. (2017). Non-Uniform Constellations for Next-Generation Digital Terrestrial Broadcast Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84743 / TESIS

This master’s theses consists of theoretical introduction which includes basic search of referenced literature about digital television systems and picture quality classification. The results of signal character measurement of selected TV channels from satellites ASTRA 1E (DVB-S) and ASTRA 1L (DVB-S2) are provided. The energy budget calculation of downlink and results of 24-hour TS error rate measurement is included as well. The video quality by DVQL metric for each particular program of CS link stream was measured during full 24 hours.

The aim of this research was to study a novel, broadband, low cost, low profile and a high-medium gain antenna in the UHF band. This has been achieved through numerical modelling, theoretical investigation and physical measurements. In this study two commercially available antenna systems are investigated in order to compare and establish potential deficiencies in the UHF antenna systems. A number of disadvantages are resolved within a novel antenna system design. The parametric study is performed for each element of the novel antenna system in order to optimise its overall performance. The indoor and outdoor measurements have been carried out in house, in order to validate the predicted results. The novel antenna system is compared to the most popular and commercially available UHF antenna systems. The study demonstrates that the novel antenna system has clear advantages such as broadband, balanced, compact and low cost when compared to the commercial antenna designs studied here. The comparison of the manufacturers' data to the measured results shows a good match, validating the outdoor measurements technique used in this research.

Ma thèse porte sur la configuration dynamique de réseaux de communication radio vérifiant un certain nombre de contraintes (ou objectifs) et l'utilisation, si possible optimale, de l'ensemble des fréquences disponibles à un instant donné. C'est un problème NP-difficile dont l'enjeu économique est important pour l'entreprise TDF. J'ai construit et mis en œuvre des méta-heuristiques hybrides originales pour résoudre ce type de problème et assurer la meilleure qualité de service (QoS) possible. Les fréquences étant une denrée rare et chère, on peut se demander si, pendant un certain temps, une seule fréquence ne suffirait pas pour couvrir les besoins d'un secteur géographique donné. Ceci permettrait d'utiliser les autres fréquences pour d'autres applications. C'est le principe de base des réseaux SFN (Single Frequency Network) qui nécessitent l'optimisation des délais de transmission, le regroupement de certains émetteurs pour construire un tel réseau et le choix de la fréquence à allouer. Du point de vue informatique, il s'agit de réaliser simultanément plusieurs optimisations. La structure d'un réseau SFN doit être ajustable au cours du temps. J'ai développé un logiciel qui réalise ces opérations, à savoir : - sélection des émetteurs pour construire des réseaux (i.e. plaques) SFN, - optimisation des écarts de transmission dans chaque SFN, - choix de la meilleure fréquence possible pour chaque SFN. Les performances de ces algorithmes sont comparées avec la QoS des plans de fréquences utilisés en France et des pays voisins. Les résultats obtenus sont encourageants. / The purpose of my thesis is the dynamic construction of radio communication networks subject to multiple constraints and the optimal (if possible) use of the set of available frequencies at time t. This is an NP-Hard problem with important economical issues. I have designed and used original hybrid meta-heuristics for solving this kind of problems and providing the best possible QoS. Frequencies are rare and expansive therefore we can ask if a single frequency would not be enough, for a while, in order to cover the needs of a given geographical area. This would allow the use of the remaining frequencies for other applications. This is the principle of Single Frequency Networks (SFN) which necessitate the simultaneous optimization of transmission delays, of the allocated frequency and of their design. I have designed an original and e_cient software which performs these operations. We give experimental results for real benchmarks provided by TDF.

L'objet de cette thèse est de doter les réseaux satellites d'accès géostationnaires d'une architecture de QoS compatible avec l'infrastructure NGN (Next Generation Network) qui entend réaliser la convergence des réseaux et services de communication existants et à venir. Dans une première étape, nous établissons un modèle de QoS NGN s'inspirant principalement de l'évolution des architectures de QoS dans les réseaux IP. Dans une deuxième étape, nous démontrons que les réseaux satellites ne disposent pas, en l'état actuel, d'une architecture de QoS suffisamment mature pour assurer un accès large bande aux futurs services IP multimédias. Afin d'y remédier, nous spécifions une architecture de QoS NGN unifiée assurant une étroite collaboration entre les mécanismes de QoS déployés à différents niveaux de communication (Application, Session, Réseau et MAC). Elle assure à la fois une différenciation de la QoS adaptée aux besoins des différentes classes d'applications au niveau IP tout en optimisant l'utilisation des ressources satellites via des mécanismes de bande passante à la demande au niveau MAC. Deux solutions applicatives assurant la corrélation dynamique entre les applications et les services réseaux différenciés sont également spécifiées et implémentées. Enfin un émulateur satellite de niveau réseau a été implémenté et nous a permis d'évaluer les garanties de QoS offertes par notre architecture et de valider leur conformité avec les besoins d'applications multimédias réelles.

<p>DVB (Digital Video Broadcasting) is the television digital system. It's however much more than a simple replacement for existing analogue television transmission, this system has many advantages such as picture quality and allows you a range of new features and services including subtitling, multiple audio tracks, interactive content, multimedia content. </p><p>The system is based in the OFDM technology, which allows DVB system to exploit the spectrum frequencies in a better way, saving spectrum, but OFDM has an important drawback that is the peak to average power ratio problem. OFDM is based on the FFT algorithms generating orthogonal subcarriers. </p><p>This thesis talks about the improvement of the PAPR problem using the soft compression method. </p><p>The simulation has been developed in Simulink® and Matlab®. With all the information presented in this thesis, any user can simulate the system. Thus, this thesis can be improved using other techniques to solve the PAPR problem.</p>

The purpose of this master thesis was to investigate how effiecient the extractionof radiofrequency quality metrics from digital video broadcast (DVB) streamscan become using software defined radio. Software defined radio (SDR) is a fairlynew technology that offers you the possibility of very flexible receivers and transmitters where it is possible to upgrade the modulation and demodulation overtime. Agama is interested in SDR for use in the Agama Analyzer, a widely deployedmonitoring probe running on top of standard services. Using SDR, Agama coulduse that in all deployments, such as DVB by cable/terrestrial/satellite (DVBC/T/S), which would simplify logistics. This thesis is an implementation of a SDR to be able to receive DVB-C. TheSDR must perform a number of adaptive algorithms in order to prevent the received symbols from being significantly different from the transmitted ones. Themain parts of the SDR include timing recovery, carrier recovery and equalization.Timing recovery performs synchronization between the transmitted and receivedsymbols and the carrier recovery performs synchronization between the carrierwave of the transmitter and the local oscillator in the receiver. The thesis discusses various methods to perform the different types of synchronizations andequalizations in order to find the most suitable methods.

DVB (Digital Video Broadcasting) is the television digital system. It's however much more than a simple replacement for existing analogue television transmission, this system has many advantages such as picture quality and allows you a range of new features and services including subtitling, multiple audio tracks, interactive content, multimedia content. The system is based in the OFDM technology, which allows DVB system to exploit the spectrum frequencies in a better way, saving spectrum, but OFDM has an important drawback that is the peak to average power ratio problem. OFDM is based on the FFT algorithms generating orthogonal subcarriers. This thesis talks about the improvement of the PAPR problem using the soft compression method. The simulation has been developed in Simulink® and Matlab®. With all the information presented in this thesis, any user can simulate the system. Thus, this thesis can be improved using other techniques to solve the PAPR problem.

The first topic of this thesis presents a bus driver design which is based on a charge recycle technique. The proposed design is mainly composed of a differential low swing circuit and a charge recycling circuit. The differential low swing signaling has been adopted to achieve low power and robust data transmission. The charge recycle is utilized to reduce power dissipation on long lines for the differential low swing signaling. The second topic is the coded orthogonal frequency division multiplex demodulation (COFDM) demodulator compliant with the European digital video broadcasting over terrestrial (DVB-T). It can recover the frequency offset of COFDM signal and dynamically select the FFT stages to synchronize the start of a symbol. The proposed design mainly contains four blocks : a time synchronization block, a frequency synchronization block, a 2K/8K FFT processor, and a channel estimation block.

This thesis proposes a complete framework of an end-to-end transmission of stereo video to mobile devices using DVB-H. Block diagram of the system is presented and operations conducted on the video at each layer are explained. Parameters and methodologies that may make a robust transmission possible are discussed. The transmission performance is analyzed in terms of error robustness under various coding methods, prediction structures, layering and protection strategies for different contents and channel conditions. It also investigates the effect of rate allocation between video quality and protection over robust transmission in erroneous environment. This works provides directive conclusions on the selection of the mentioned parameters and methods.