Dissertations / Theses on the topic 'Terrestrial digital broadcasting'

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

[EN] Next-generation terrestrial broadcasting targets at enhancing spectral efficiency to overcome the challenges derived from the spectrum shortage as a result of the progressive allocation of frequencies - the so-called Digital Dividend - to satisfy the growing demands for wireless broadband capacity. Advances in both transmission standards and video coding are paramount to enable the progressive roll-out of high video quality services such as HDTV (High Definition Televison) or Ultra HDTV. The transition to the second generation European terrestrial standard DVB-T2 and the introduction of MPEG-4/AVC video coding already enables the transmission of 4-5 HDTV services per RF (Radio Frequency) channel. However, the impossibility to allocate higher bit-rate within the remaining spectrum could jeopardize the evolution of the DTT platforms in favour of other high-capacity systems such as the satellite or cable distribution platforms. Next steps are focused on the deployment of the recently released High Efficiency Video Coding (HEVC) standard, which provides more than 50% coding gain with respect to AVC, with the next-generation terrestrial standards. This could ensure the competitiveness of the DTT. This dissertation addresses the use of multi-RF channel aggregation technologies to increase the spectral efficiency of future DTT networks. The core of the Thesis are two technologies: Time Frequency Slicing (TFS) and Channel Bonding (CB). TFS and CB consist in the transmission of the data of a TV service across multiple RF channels instead of using a single channel. CB spreads data of a service over multiple classical RF channels (RF-Mux). TFS spreads the data by time-slicing (slot-by-slot) across multiple RF channels which are sequentially recovered at the receiver by frequency hopping. Transmissions using these features can benefit from capacity and coverage gains. The first one comes from a more efficient statistical multiplexing (StatMux) for Variable Bit Rate (VBR) services due to a StatMux pool over a higher number of services. Furthermore, CB allows increasing service data rate with the number of bonded RF channels and also advantages when combined with SVC (Scalable Video Coding). The coverage gain comes from the increased RF performance due to the reception of the data of a service from different RF channels rather that a single one that could be, eventually, degraded. Robustness against interferences is also improved since the received signal does not depend on a unique potentially interfered RF channel. TFS was firstly introduced as an informative annex in DVB-T2 (not normative) and adopted in DVB-NGH (Next Generation Handheld). TFS and CB are proposed for inclusion in ATSC 3.0. However, they have never been implemented. The investigations carried out in this dissertation employ an information-theoretical approach to obtain their upper bounds, physical layer simulations to evaluate the performance in real systems and the analysis of field measurements that approach realistic conditions of the network deployments. The analysis report coverage gains about 4-5 dB with 4 RF channels and high capacity gains already with 2 RF channels. This dissertation also focuses on implementation aspects. Channel bonding receivers require one tuner per bonded RF channel. The implementation of TFS with a single tuner demands the fulfilment of several timing requirements. However, the use of just two tuners would still allow for a good performance with a cost-effective implementation by the reuse of existing chipsets or the sharing of existing architectures with dual tuner operation such as MIMO (Multiple Input Multiple Output).
[ES] La televisión digital terrestre (TDT) de última generación está orientada a una necesaria mejora de la eficiencia espectral con el fin de abordar los desafíos derivados de la escasez de espectro como resultado de la progresiva asignación de frecuencias - el llamado Dividendo Digital - para satisfacer la creciente demanda de capacidad para la banda ancha inalámbrica. Los avances tanto en los estándares de transmisión como de codificación de vídeo son de suma importancia para la progresiva puesta en marcha de servicios de alta calidad como la televisión de Ultra AD (Alta Definición). La transición al estándar europeo de segunda generación DVB-T2 y la introducción de la codificación de vídeo MPEG-4 / AVC ya permite la transmisión de 4-5 servicios de televisión de AD por canal RF (Radiofrecuencia). Sin embargo, la imposibilidad de asignar una mayor tasa de bit sobre el espectro restante podría poner en peligro la evolución de las plataformas de TDT en favor de otros sistemas de alta capacidad tales como el satélite o las distribuidoras de cable. El siguiente paso se centra en el despliegue del reciente estándar HEVC (High Efficiency Video Coding), que ofrece un 50% de ganancia de codificación con respecto a AVC, junto con los estándares terrestres de próxima generación, lo que podría garantizar la competitividad de la TDT en un futuro cercano. Esta tesis aborda el uso de tecnologías de agregación de canales RF que permitan incrementar la eficiencia espectral de las futuras redes. La tesis se centra en torno a dos tecnologías: Time Frequency Slicing (TFS) y Channel Bonding (CB). TFS y CB consisten en la transmisión de los datos de un servicio de televisión a través de múltiples canales RF en lugar de utilizar un solo canal. CB difunde los datos de un servicio a través de varios canales RF convencionales formando un RF-Mux. TFS difunde los datos a través de ranuras temporales en diferentes canales RF. Los datos son recuperados de forma secuencial en el receptor mediante saltos en frecuencia. La implementación de estas técnicas permite obtener ganancias en capacidad y cobertura. La primera de ellas proviene de una multiplexación estadística (StatMux) de servicios de tasa variable (VBR) más eficiente. Además, CB permite aumentar la tasa de pico de un servicio de forma proporcional al número de canales así como ventajas al combinarla con codificación de vídeo escalable. La ganancia en cobertura proviene de un mejor rendimiento RF debido a la recepción de los datos de un servicio desde diferentes canales en lugar uno sólo que podría estar degradado. Del mismo modo, es posible obtener una mayor robustez frente a interferencias ya que la recepción o no de un servicio no depende de si el canal que lo alberga está o no interferido. TFS fue introducido en primer lugar como un anexo informativo en DVB-T2 (no normativo) y posteriormente fue adoptado en DVB-NGH (Next Generation Handheld). TFS y CB han sido propuestos para su inclusión en ATSC 3.0. Aún así, nunca han sido implementados. Las investigaciones llevadas a cabo en esta Tesis emplean diversos enfoques basados en teoría de la información para obtener los límites de ganancia, en simulaciones de capa física para evaluar el rendimiento en sistemas reales y en el análisis de medidas de campo. Estos estudios reportan ganancias en cobertura en torno a 4-5 dB con 4 canales e importantes ganancias en capacidad aún con sólo 2 canales RF. Esta tesis también se centra en los aspectos de implementación. Los receptores para CB requieren un sintonizador por canal RF agregado. La implementación de TFS con un solo sintonizador exige el cumplimiento de varios requisito temporales. Sin embargo, el uso de dos sintonizadores permitiría un buen rendimiento con una implementación más rentable con la reutilización de los actuales chips o su introducción junto con las arquitecturas existentes que operan con un doble sintonizador tales como
[CAT] La televisió digital terrestre (TDT) d'última generació està orientada a una necessària millora de l'eficiència espectral a fi d'abordar els desafiaments derivats de l'escassetat d'espectre com a resultat de la progressiva assignació de freqüències - l'anomenat Dividend Digital - per a satisfer la creixent demanda de capacitat per a la banda ampla sense fil. Els avanços tant en els estàndards de transmissió com de codificació de vídeo són de la màxima importància per a la progressiva posada en marxa de serveis d'alta qualitat com la televisió d'Ultra AD (Alta Definició). La transició a l'estàndard europeu de segona generació DVB-T2 i la introducció de la codificació de vídeo MPEG-4/AVC ja permet la transmissió de 4-5 serveis de televisió d'AD per canal RF (Radiofreqüència). No obstant això, la impossibilitat d'assignar una major taxa de bit sobre l'espectre restant podria posar en perill l'evolució de les plataformes de TDT en favor d'altres sistemes d'alta capacitat com ara el satèl·lit o les distribuïdores de cable. El següent pas se centra en el desplegament del recent estàndard HEVC (High Efficiency Vídeo Coding), que oferix un 50% de guany de codificació respecte a AVC, junt amb els estàndards terrestres de pròxima generació, la qual cosa podria garantir la competitivitat de la TDT en un futur pròxim. Aquesta tesi aborda l'ús de tecnologies d'agregació de canals RF que permeten incrementar l'eficiència espectral de les futures xarxes. La tesi se centra entorn de dues tecnologies: Time Frequency Slicing (TFS) i Channel Bonding (CB). TFS i CB consistixen en la transmissió de les dades d'un servei de televisió a través de múltiples canals RF en compte d'utilitzar un sol canal. CB difon les dades d'un servei a través d'uns quants canals RF convencionals formant un RF-Mux. TFS difon les dades a través de ranures temporals en diferents canals RF. Les dades són recuperades de forma seqüencial en el receptor per mitjà de salts en freqüència. La implementació d'aquestes tècniques permet obtindre guanys en capacitat i cobertura. La primera d'elles prové d'una multiplexació estadística (StatMux) de serveis de taxa variable (VBR) més eficient. A més, CB permet augmentar la taxa de pic d'un servei de forma proporcional al nombre de canals així com avantatges al combinar-la amb codificació de vídeo escalable. El guany en cobertura prové d'un millor rendiment RF a causa de la recepció de les dades d'un servei des de diferents canals en lloc de només un que podria estar degradat. De la mateixa manera, és possible obtindre una major robustesa enfront d'interferències ja que la recepció o no d'un servei no depén de si el canal que l'allotja està o no interferit. TFS va ser introduït en primer lloc com un annex informatiu en DVB-T2 (no normatiu) i posteriorment va ser adoptat en DVB-NGH (Next Generation Handheld). TFS i CB han sigut proposades per a la seva inclusió en ATSC 3.0. Encara així, mai han sigut implementades. Les investigacions dutes a terme en esta Tesi empren diverses vessants basades en teoria de la informació per a obtindre els límits de guany, en simulacions de capa física per a avaluar el rendiment en sistemes reals i en l'anàlisi de mesures de camp. Aquestos estudis reporten guanys en cobertura entorn als 4-5 dB amb 4 canals i importants guanys en capacitat encara amb només 2 canals RF. Esta tesi també se centra en els aspectes d'implementació. Els receptors per a CB requerixen un sintonitzador per canal RF agregat. La implementació de TFS amb un sol sintonitzador exigix el compliment de diversos requisit temporals. No obstant això, l'ús de dos sintonitzadors permetria un bon rendiment amb una implementació més rendible amb la reutilització dels actuals xips o la seua introducció junt amb les arquitectures existents que operen amb un doble sintonitzador com ara MIMO (Multiple Input Multiple Output).
Giménez Gandia, JJ. (2015). Improved Spectrum Usage with Multi-RF Channel Aggregation Technologies for the Next-Generation Terrestrial Broadcasting [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52520
TESIS

This study compares the impact of media ownership, regulation and policy, and technology adoption on the introduction of digital terrestrial television in the United States and Mainland China. Through the use of a case study approach, a qualitative and quantitative examination is given. The results indicate that private group ownership throughout the U.S. digital terrestrial television industry and state ownership in China's television industry lead to the different paths to digital transition. Both governments, however, are deeply involved in respective digital initiatives and play an important role in the implementation from analog to digital. The technical standard adoption in the two countries places the underpinning for the future development of digital television (DTV), which also results in China lagging behind the United States by almost ten years. The differences of technological environments in households and income among consumers in the two countries further predict the intention to DTV adoption.

Made available in DSpace on 2015-04-22T22:00:47Z (GMT). No. of bitstreams: 1 jose.pdf: 2255469 bytes, checksum: cebe37770c4719e5ebf2b60e4ae0d2a6 (MD5) Previous issue date: 2013-06-07
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Currently, the majority of multicarrier transmission systems are based on the Fourier transform, which is used as frequency multiplexing technique. The main advantages of this approach include multipath immunity and low computational complexity, due to the use of a family of fast algorithms, known as Fast Fourier Transform (FFT). However, when used to provide a robust transmission, this technique presents some disadvantages, like the need for a cyclic prefix, which demands part of the useful datarate. In this work, a study for verifying the possibility of replacing the FFT, by the wavelet transform, was carried out, which has the potential to raise some advantages, such as the removal of the cyclic prefix and a simpler synchronization procedure. A computational model for the transmission layer of the Integrated Services Digital Broadcasting Terrestrial, Brazilian version (ISDB-Tb) was created, aiming to provide a direct comparison between two versions: the traditional one, which is based on FFT, and a new proposal, which is based on wavelets. Such an evaluation was performed through the relation between error bit rate and signal-to-noise ratio, in additive white gaussian noise, Rayleigh and Rician fading and also in frequency-selective Rayleigh fading channels. Similar comparisons were also performed for the ETSI TS 101 475 (HIPERLAN-2) and Digital Video Broadcasting Terrestrial (DVB-T) systems. The simulation results show that the wavelet-based systems present a similar performance, when compared with the FFT-based ones, for the chosen channel models, and without employing a cyclic prefix, which allows a more efficiente spectrum use.
Atualmente, uma grande parte dos sistemas de transmissão multiportadoras é baseada na transformada de Fourier, como técnica de multiplexação em frequência. Dentre as suas principais vantagens, encontram-se a imunidade a multipercursos e a baixa complexidade computacional, através de algoritmos rápidos conhecidos como Fast Fourier Transform (FFT). Esta técnica, entretanto, para proporcionar uma transmissão robusta, apresenta a desvantagem de exigir prefixo cíclico, o que resulta no consumo de uma fatia do espectro útil. Neste trabalho, um estudo para se verificar a viabilidade de substituição da FFT pela transformada wavelet foi realizado, o que promete trazer algumas vantagens, tais como a não exigência de prefixo cíclico e uma sincronização mais simples. Um modelo computacional para a camada de transmissão do Integrated Services Digital Broadcasting - Terrestrial, Brazilian version (ISDB-Tb) foi criado, com o objetivo de proporcionar uma comparação entre duas versões: a atual, baseada em FFT, e uma nova proposta, baseada em wavelets. Tal avaliação foi realizada em termos das curvas de taxa de erro de bit versus relação sinal ruído, em canais com adição de ruído gaussiano branco, com desvanecimento plano de Rayleigh e Rice e também com desvanecimento seletivo em frequência de Rayleigh. Comparações similares também foram realizadas para os sistemas ETSI TS 101 475 (HIPERLAN-2) e Digital Video Broadcasting Terrestrial (DVB-T). Os resultados obtidos mostram que os sistemas baseados em wavelets apresentam desempenhos similares aos dos baseados em FFT, para os modelos de canal simulados, com a vantagem adicional de não utilizarem prefixo cíclico, o que promove um uso mais eficiente do espectro.

Made available in DSpace on 2016-03-15T19:37:57Z (GMT). No. of bitstreams: 1 RICHARD JOHN LINTULAHTI OLANDIM.pdf: 2276167 bytes, checksum: 0d3c0536034c612074740ab02558a1be (MD5) Previous issue date: 2015-06-25
In Brazil, the broadcasting system for television content in high definition is the ISDB-Tb. Although robust, the content transmission in this system, like in any radio frequency propagation, can suffer from external attenuating factors, such as distortion by multipath propagation. One of the techniques used in radio communications for minimizing the effects of this type of distortion is the spatial diversity reception, which uses multiple antennas connected to a single receiver. The signals, received by different antennas, are combined, in a technique known as MRC or Maximal Ratio Combiner, so that the output signal-to-noise ratio is greater than the individual signal-to-noise ratios, allowing the successfully decoding of the received content, even though the individual signal in each antenna does not have sufficient quality to be decoded independently. This study aims to establish a method of spatial diversity in receiving television signals in ISDB-Tb, pondering between the advantages and disadvantages of their use in edge regions of coverage, where the reception of the Brazilian digital TV system is not yet total.
No Brasil, o sistema de radiodifusão para conteúdos televisivos em alta definição é o ISDB-Tb. Apesar de robusto, a transmissão de conteúdos neste sistema, como qualquer propagação em radiofrequência, pode sofrer com fatores externos atenuantes, como por exemplo a distorção por propagação em multi-percurso. Uma das técnicas utilizadas em radiocomunicação para que se minimizem os efeitos deste tipo de distorção é a diversidade espacial na recepção, que utiliza múltiplas antenas conectadas a um mesmo receptor. Os sinais, recebidos pelas diferentes antenas, são trabalhados em uma técnica conhecida como MRC ou Combinação de Máxima Razão, de modo que a relação sinal-ruído de saída seja maior do que as relações sinal-ruído individuais, permitindo a decodificação do conteúdo com sucesso, mesmo que os sinais individuais em cada antena não tenham qualidade suficiente para serem decodificados independentemente. Este estudo tem como objetivo propor um método de diversidade espacial na recepção de sinais televisivos no padrão brasileiro ISDB-Tb, ponderando entre as vantagens e desvantagens de sua utilização em regiões de borda de cobertura, onde a recepção do sistema brasileiro de TV digital ainda não é total.

DAB (Digital Audio Broadcasting) is the radio digital system developed as an european standard by the ETSI, EN 300 400, based on the Eureka-147 group works, to improve the performance of the analogue radio systems (AM and FM). The system is based on the OFDM technology which allows DAB to exploit the spectrum frequencies in a better way with a higher quality of sound for mobile receivers specially. The main part of the OFDM system is based on the FFT algorithms to spread the data flow over different orthogonal carriers. The simulation has been developed in Simulink^TMand Matlab^TMand the layout designed follows faithfully the standard for the transmission system. The simulation can be reloaded by the user with the information presented in this thesis. Thus, this work can be continued to complete the DAB whole system simulation. The results obtained running this simulation show the main DAB system characteristics.

Os sistemas de telecomunicações sem fios dependem fundamentalmente do espectro de frequências radioeléctrico. Actualmente, os estudos dos organismos reguladores indicam que a utilização do espectro com licenciamento fixo é subaproveitada e que existe o problema da escassez de oferta do espectro. Assim, com o aumento da procura de novos serviços e do número de utilizadores os operadores de telecomunicações têm por obrigação de procurar novas soluções, que visem o aumento da eficiência espectral através de técnicas avançadas de processamento para a gestão do espectro. Esta dissertação propõe a operação do LTE em frequências mais baixas (UHF) para o aumento da eficiência espectral em conjunto com a gestão do espectro de rádio com atribuição temporária, no contexto da inter-coexistência. Assim, a transição da televisão analógica para a TDT oferece uma nova oportunidade no aproveitamento das bandas UHF para o aumento da oferta por parte dos operadores de telecomunicações. Em particular, os canais nas bandas UHF são adequados para aplicações móveis, devido às suas excelentes condições de propagação e penetração (superior) em edifícios. Além disso, o comprimento de onda nestas bandas é suficientemente curto, permitindo construir antenas com um tamanho adequado para uso portátil. Como possibilita a cobertura eficiente por parte dos operadores de telecomunicações de vastas áreas geográficas com um menor número de estações base. Assim sendo, a atribuição temporária de espectro nas bandas de TV (espaços vazios da TV, TV White Spaces - TVWS) com direitos exclusivos temporários é muito valiosa. Dado que os TVWS estarão disponíveis em 2012, as bandas utilizadas são um sério candidato para suportar o sistema LTE. As vantagens da utilização do sistema LTE são a flexibilidade em operar em várias bandas de frequência e em várias larguras de banda. No entanto, a maioria dos países europeus pensa utilizar a frequência 2.6 GHz para o sistema LTE o que poderá limitar a sua cobertura e diminuir o seu desempenho. Assim, através da utilização temporária das portadoras LTE nos TVWS (700MHz) poderá obter-se uma capacidade extra em redes próximas da saturação ou de cobertura melhorada. Para se observarem as diferenças entre a utilização dos 2.6GHz e os 700 MHz desenvolveu-se um simulador de LTE em MATLABTM, numa linguagem script orientada a objectos. O simulador permite obter resultados de cobertura e capacidade nas frequências actuais (Legacy) e nos TVWS. No processo de atribuição dinâmico dos recursos do LTE, o simulador utiliza dois algoritmos de Radio Resource Management (RRM), no contexto de Multi Band Access (MBA). Um dos algoritmos atribui recursos das duas bandas de forma equilibrada enquanto a outra dá prioridade a um das bandas, originado numa utilização mais eficiente dos recursos disponíveis. O objectivo é maximizar a utilização dos TVWS na atribuição dinâmica do espectro e minimizar a fragmentação do espectro, mantendo-se a QoS e evitar interferências entre os sistemas secundários e primário.
The wireless systems are dependent of the electromagnetic spectrum. The studies from the regulatory bodies show that, with a permanent licensing, the spectrum is underused; and there exists a shortage in the spectrum availability. Therefore, with the introduction of new services and the growth in the number of subscribers, operators face a new challenge and must find engineering solutions to increase the spectral efficiency and manage the available spectrum. This thesis purposes the extension of LTE operation over low frequency bands (UHF) in order to increase the spectral efficiency in conjunction with temporary use of the available spectrum, in the context of inter-coexistence. Hence, the transition to digital TV (i.e., digital TV switch-over) represents an opportunity to re-use UHF band with the respective increase in the operator's services offers. Namely, the UHF band is considered valuable for mobile services due to its excellent propagation characteristics and penetration through walls. Besides, the wavelength in this band is small enough to allow the construction of antennas that can be used in mobile devices. Additionally, in this band, the cell radius is larger than in upper frequencies (due to the lower path loss) which allow for operators to cover larger areas with less base stations. Therefore, the licensing process to use frequency spectrum in the TV bands for mobile services with temporary exclusive rights is seen to be very valuable. These channels are known as TV white spaces (TVWS). Since TVWS will be available in 2012, they are a serious candidate to support the LTE standard. The advantages of LTE are related with the flexibility to operate in different frequencies with various bandwidths. However, most of the European countries intent to use the 2.6 GHz frequency for LTE networks, which may limit the system's coverage and performance. Hence, with the use of temporary LTE carriers in TVWS (700MHz) it is possible to achieve extra capacity in networks near the saturation point and/or with ameliorated coverage. For this purpose, in order to evaluate the differences in terms of performance between LTE networks at 2.6 GHz and 700 MHz, a simulator was developed using a script language in MATLABTM . The simulator enables to achieve results about the coverage and capacity in the actual Legacy frequencies as well as in TVWS. In the dynamic process of distributing the LTE radio resources, two algorithms were used for Radio Resource Management (RRM), in a Multi Band Access (MBA) context. One of the algorithms try to equally distribute the resources while the other prioritize one of the bands against the other, lending to a more efficient use of available resources. The objective is to maximize the use of TVWS and minimize the fragmentation of the spectrum while keeping the comparable QoS levels.

La diffusion de signaux de télévision numérique est soumise à un certain nombre de contraintes. Notamment les niveaux de rayonnements non essentiels (RNE) émis en dehors des fréquences d’émission doivent être inférieurs à un seuil fixé par les instances de régulation afin de ne pas brouiller les autres canaux de diffusion. Compte tenu du caractère non-linéaire des amplificateurs de puissance, l’augmentation de la puissance diffusée permet d’augmenter le rendement des amplificateurs mais augmente en même temps le niveau des RNE. Les diffuseurs doivent donc trouver un compromis entre le niveau des RNE émis et le coût de revient des équipements de diffusion. Jusque là, les programmes DVB-T sont amplifiés en monocanal, c’est-à-dire que chaque multiplex est amplifié par un amplificateur. Le rendement est optimisé en utilisant un précorrecteur numérique afin de limiter les intermodulations dans le canal et dans les canaux adjacents, et en utilisant un filtre de canal afin de nettoyer le spectre. Cette technique de précorrection numérique, simulée dans ce mémoire, permet effectivement d’améliorer les shoulders et le TEB. L’amplification multicanal permettrait un gain important car un seul amplificateur est nécessaire pour traiter plusieurs multiplex. Cependant sans linérisation, il est nécessaire d’utiliser l’amplificateur de puissance avec un recul de puissance très élevé pour que le seuil maximal des RNE ne soit pas atteint. Nous proposons ici un précorrecteur multicanal qui permet de diminuer Digital television broadcasting is subjected to a certain number of contraints
Among others, the spurious levels must be lower than the threshold imposed by regulation authorities to avoid disturbing the other channels. Taking in account the non linearity nature of power amplifiers, increase the emitted power leads to increase the efficiency but also the spurious level. Consequently, broadcasters should reach a compromise between spurious level and transmitters cost. DVB-T programs are currently amplified in mono-channel, i. E. Each multiplex is amplified by its own amplifier. The efficiency is improved using a digital predistorter and a band-pass filter. The digital predistorter minimizes in band and out of band intermodulations, and the filter cleans the spectrum. The digital predistortion method, simulated in this memory, allows a great improvement of the shoulders and the BER. Multi-channel amplification would conduce to a high profit because only one amplifier is necessary to treat several channels. However without linearization, the amplifier must be used with a very high output back-o? in order to keep the spurious level below the fixed threshold. In this thesis we present a multi-channel predistorter that highly improves the shoulders and the spurious level

Cette thèse a pour objectif l'analyse du système de télévision numérique chinois (DTMB) et l'optimisation de sa fonction d'estimation de canal. Tout d'abord, une analyse approfondie de ce système est effectuée en comparaison du système DVB-T en termes de spécifications, d'efficacité spectrale et de performances. Ensuite, la fonction d'estimation de canal basée sur la séquence pseudo-aléatoire du système est étudiée dans les domaines temporel et fréquentiel, et plusieurs améliorations sont apportées aux méthodes typiques afin de notamment gérer les canaux très dispersifs en temps. Enfin, de nouveaux procédés itératifs aidés par les données et peu complexes sont proposés pour raffiner les estimés de canal. Les fonctions de décodage de canal et d'entrelacement sont exclues de la boucle et des fonctions de filtrage temps/fréquence sont étudiées pour fiabiliser les estimations. Ces nouveaux algorithmes démontrent leur efficacité par rapport aux méthodes courantes de la littérature.

This thesis is focused on a receiver for digital television broadcasting set-top box, mainly on its features, parameters and measurement. The important point of this work is the possibility to analyze and visualize the parallel transport stream in the same time and the solution of this problem. The principle of tuner and its measuring is deeply discussed. The text is supported with oscilloscope screenshots in particular parts of decoding stream. The set-top box is modified for laboratory measurement purpose and the transport stream output is added. An example laboratory exercise was created as a part of this work.

Desde comienzos del siglo XXI, los sistemas de radiodifusión terrestre han sido culpados de un uso ineficiente del espectro asignado. Para aumentar la eficiencia espectral, los organismos de estandarización de TV digital comenzaron a desarrollar la evolución técnica de los sistemas de TDT de primera generación. Entre otros, uno de los objetivos principales de los sistemas de TDT de próxima generación (DVB-T2 y ATSC 3.0) es proporcionar simultáneamente servicios de TV a dispositivos móviles y fijos. El principal inconveniente de esta entrega simultánea son los diferentes requisitos de cada condición de recepción. Para abordar estas limitaciones, se han considerado diferentes técnicas de multiplexación. Mientras que DVB-T2 acomete la entrega simultánea de los dos servicios mediante TDM, ATSC 3.0 adoptó la Multiplexación por División en Capas (LDM). LDM puede superar a TDM y a FDM al aprovechar la relación de Protección de Error Desigual (UEP), ya que ambos servicios, llamados capas, utilizan todos los recursos de frecuencia y tiempo con diferentes niveles de potencia. En el lado del receptor, se distinguen dos implementaciones, de acuerdo con la capa a decodificar. Los receptores móviles solo están destinados a obtener la capa superior, conocida como Core Layer (CL). Para no aumentar su complejidad en comparación con los receptores de capa única, la capa inferior, conocida como Enhanced Layer (EL), es tratada como un ruido adicional en la decodificación. Los receptores fijos aumentan su complejidad, ya que deben realizar un proceso de Cancelación de Interferencia (SIC) sobre la CL para obtener la EL. Para limitar la complejidad adicional de los receptores fijos, las capas de LDM en ATSC 3.0 están configuradas con diferentes capacidades de corrección, pero comparten el resto de bloques de la capa física, incluido el TIL, el PP, el tamaño de FFT, y el GI. Esta disertación investiga tecnologías avanzadas para optimizar el rendimiento de LDM. Primero se propone una optimización del proceso de demapeo para las dos capas de LDM. El algoritmo propuesto logra un aumento de capacidad, al tener en cuenta la forma de la EL en el proceso de demapeo de la CL. Sin embargo, el número de distancias Euclidianas a computar puede aumentar significativamente, conduciendo no solo a receptores fijos más complejos, sino también a receptores móviles más complejos. A continuación, se determina la configuración de piloto ATSC 3.0 más adecuada para LDM. Teniendo en cuenta que las dos capas comparten el mismo PP, surge una contrapartida entre la densidad de pilotos (CL) y la redundancia sobre los datos (EL). A partir de los resultados de rendimiento, se recomienda el uso de un PP no muy denso, ya que ya han sido diseñados para hacer frente a ecos largos y altas velocidades. La amplitud piloto óptima depende del estimador de canal en los receptores (ej., se recomienda la amplitud mínima para una implementación Wiener, mientras que la máxima para una implementación FFT). También se investiga la potencial transmisión conjunta de LDM con tres tecnologías avanzadas adoptadas en ATSC 3.0: las tecnologías de agregación MultiRF, los esquemas de MISO distribuido y los de MIMO colocalizado. Se estudian los potenciales casos de uso, los aspectos de implementación del transmisor y el receptor, y las ganancias de rendimiento de las configuraciones conjuntas para las dos capas de LDM. Las restricciones adicionales de combinar LDM con las tecnologías avanzadas se consideran admisibles, ya que las mayores demandas ya están contempladas en ATSC 3.0 (ej., una segunda cadena de recepción). Se obtienen ganancias significativas en condiciones de recepción peatonal gracias a la diversidad en frecuencia proporcionada por las tecnologías MultiRF. La conjunción de LDM con esquemas de MISO proporciona ganancias de rendimiento significativas en redes SFN para la capa fija con el esquema de Alamouti.
Since the beginning of the 21st century, terrestrial broadcasting systems have been blamed of an inefficient use of the allocated spectrum. To increase the spectral efficiency, digital television Standards Developing Organizations settled to develop the technical evolution of the first-generation DTT systems. Among others, a primary goal of next-generation DTT systems (DVB-T2 and ATSC 3.0) is to simultaneously provide TV services to mobile and fixed devices. The major drawback of this simultaneous delivery is the different requirement of each reception condition. To address these constraints different multiplexing techniques have been considered. While DVB-T2 fulfilled the simultaneous delivery of the two services by TDM, ATSC 3.0 adopted the LDM technology. LDM can outperform TDM and FDM by taking advantage of the UEP ratio, as both services, namely layers, utilize all the frequency and time resources with different power levels. At receiver side, two implementations are distinguished, according to the intended layer. Mobile receivers are only intended to obtain the upper layer, known as CL. In order not to increase their complexity compared to single layer receivers, the lower layer, known as EL is treated as an additional noise on the CL decoding. Fixed receivers, increase their complexity, as they should performed a SIC process on the CL for getting the EL. To limit the additional complexity of fixed receivers, the LDM layers in ATSC 3.0 are configured with different error correction capabilities, but share the rest of physical layer parameters, including the TIL, the PP, the FFT size, and the GI. This dissertation investigates advanced technologies to optimize the LDM performance. A demapping optimization for the two LDM layers is first proposed. A capacity increase is achieved by the proposed algorithm, which takes into account the underlying layer shape in the demapping process. Nevertheless, the number of Euclidean distances to be computed can be significantly increased, contributing to not only more complex fixed receivers, but also more complex mobile receivers. Next, the most suitable ATSC 3.0 pilot configuration for LDM is determined. Considering the two layers share the same PP a trade-off between pilot density (CL) and data overhead (EL) arises. From the performance results, it is recommended the use of a not very dense PP, as they have been already designed to cope with long echoes and high speeds. The optimum pilot amplitude depends on the channel estimator at receivers (e.g. the minimum amplitude is recommended for a Wiener implementation, while the maximum for a FFT implementation). The potential combination of LDM with three advanced technologies that have been adopted in ATSC 3.0 is also investigated: MultiRF technologies, distributed MISO schemes, and co-located MIMO schemes. The potential use cases, the transmitter and receiver implementations, and the performance gains of the joint configurations are studied for the two LDM layers. The additional constraints of combining LDM with the advanced technologies is considered admissible, as the greatest demands (e.g. a second receiving chain) are already contemplated in ATSC 3.0. Significant gains are found for the mobile layer at pedestrian reception conditions thanks to the frequency diversity provided by MultiRF technologies. The conjunction of LDM with distributed MISO schemes provides significant performance gains on SFNs for the fixed layer with Alamouti scheme. Last, considering the complexity in the mobile receivers and the CL performance, the recommended joint configuration is MISO in the CL and MIMO in the EL.
Des de començaments del segle XXI, els sistemes de radiodifusió terrestre han sigut culpats d'un ús ineficient de l'espectre assignat. Per a augmentar l'eficiència espectral, els organismes d'estandardització de TV digital van començar a desenvolupar l'evolució tècnica dels sistemes de TDT de primera generació. Entre altres, un dels objectius principals dels sistemes de TDT de pròxima generació (DVB-T2 i el ATSC 3.0) és proporcionar simultàniament serveis de TV a dispositius mòbils i fixos. El principal inconvenient d'aquest lliurament simultani són els diferents requisits de cada condició de recepció. Per a abordar aquestes limitacions, s'han considerat diferents tècniques de multiplexació. Mentre que DVB-T2 escomet el lliurament simultani dels dos serveis mitjançant TDM, ATSC 3.0 va adoptar la Multiplexació per Divisió en Capes (LDM). LDM pot superar a TDM i a FDM en aprofitar la relació de Protecció d'Error Desigual (UEP), ja que tots dos serveis, cridats capes, utilitzen tots els recursos de freqüència i temps amb diferents nivells de potència. En el costat del receptor, es distingeixen dues implementacions, d'acord amb la capa a decodificar. Els receptors mòbils solament estan destinats a obtenir la capa superior, coneguda com Core Layer (CL). Per a no augmentar la seua complexitat en comparació amb els receptors de capa única, la capa inferior, coneguda com Enhanced Layer (EL), és tractada com un soroll addicional en la decodificació. Els receptors fixos augmenten la seua complexitat, ja que han de realitzar un procés de Cancel·lació d'Interferència (SIC) sobre la CL per a obtenir l'EL. Per a limitar la complexitat addicional dels receptors fixos, les capes de LDM en ATSC 3.0 estan configurades amb diferents capacitats de correcció, però comparteixen la resta de blocs de la capa física, inclòs el TIL, el PP, la grandària de FFT i el GI. Aquesta dissertació investiga tecnologies avançades per a optimitzar el rendiment de LDM. Primer es proposa una optimització del procés de demapeo per a les dues capes de LDM. L'algoritme proposat aconsegueix un augment de capacitat, en tenir en compte la forma de l'EL en el procés de demapeo de la CL. No obstant açò, el nombre de distàncies Euclidianes a computar pot augmentar significativament, conduint NO sols a receptors fixos més complexos, sinó també a receptors mòbils més complexos. A continuació, es determina la configuració de pilot ATSC 3.0 més adequada per a LDM. Tenint en compte que les dues capes comparteixen el mateix PP, es produeix una contrapartida entre la densitat de pilots (CL) i la redundància sobre les dades (EL). A partir dels resultats de rendiment, es recomana l'ús d'un PP no gaire dens, ja que ja han sigut dissenyats per a fer front a ecos llargs i altes velocitats. L'amplitud pilot òptima depèn de l'estimador de canal en els receptors (ex., es recomana l'amplitud mínima per a una implementació Wiener, mentre que la màxima per a una implementació FFT). També s'investiga la potencial transmissió conjunta de LDM amb tres tecnologies avançades adoptades en ATSC 3.0: les tecnologies d'agregació de MultiRF, els esquemes de MISO distribuït i els de MIMO colocalitzat. S'estudien els potencials casos d'ús, els principals aspectes d'implementació del transmissor i el receptor, i els guanys de rendiment de les configuracions conjuntes per a les dues capes de LDM. Les restriccions addicionals de combinar LDM amb les tecnologies avançades es consideren admissibles, ja que les majors demandes ja estan contemplades en ATSC 3.0 (ex., una segona cadena de recepció). S'obtenen guanys significatius per a la capa mòbil en condicions de recepció per als vianants gràcies a la diversitat en freqüència proporcionada per les tecnologies MultiRF. La conjunció de LDM amb esquemes MISO distribuïts proporciona guanys de rendiment significatius en xarxes SFN per a la capa fixa amb l'esquema d'Alamouti.
Garro Crevillén, E. (2018). Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/105559
TESIS

碩士
國立交通大學
科技管理所
89
Due to the progress in digital technologies, digital TV has become an emerging multimedia communications vehicle that will be one of the major broadband accesses to information and entertainment content from home. Because terrestrial TV broadcasting makes use of public resource of radio spectrum, a well conceived government policy is essential to make DTV a driving force to promte the econmic, social cultural and educational development. This research explores the trend of DTV new services and applications, focues on the issues of transmission standards and DTV channel ownership and management. Scholars in media and communication management are surveyed about their opinions, on several aspects in DTV policies and regulations. The findings of this research shall provide as input to the regulators.

碩士
逢甲大學
電子工程所
94
With the advances of science and technology, television broadcasting also moves into the digital era. Therefore, channel coding-decoding is worthy of conferring and researching because it is important for digital television broadcasting systems. The DVB-T published by European Broadcast Union makes use of Reed-Solomon code and viterbi decoder for channel codec. In this thesis we, first at all, compare some Reed-Solomon decoders that take account of area and find the best algorithm of them in this system. Thereafter we reform a structure of finite field multiplier which reducing the amount of logic gate without losing operation speed to optimize the speed of a Reed-Solomon decoder after reducing area. By the two ways, this decoder is designed with VHDL and verified through APEX20K Demo Board by Logic Analyzer. It occupies 2228 logic elements and 5400 memory bits.

碩士
雲林科技大學
電機工程系碩士班
98
The major goal of this thesis is to reduce the number of iterations required by the algorithm in DVB-T2 decoding systems. The overall system is composed of several parts: the outer BCH (Bose, Chaudhuri, and Hocquenghem) code, which can be used for overcoming bursty errors; the inner LDPC (low-density parity-check) code, whose purpose is to increase coding gains; the bit interleaver, which scrambles data bits so that the original message will not suffer too much on bursty channels. After message signals are transmitted through Rayleigh channels, received bits are deinterleaved by using a column twist deinterleaver followed by a parity deinterleaver. Min-Sum Algorithm is used in the inner decoder, which can effectively reduce number of iterations and error rates. Berlekamp-Massey algorithm is then applied in the outer decoder to construct the error location equation. Finally, Chien Search algorithm is used to efficiently locate the locations of errors. Simulation results show that, under all of the specifications for the numbers of column Nc being 8, 12, and 16, and for various code rates (i.e, 1/2, 3/5, 2/3, 3/4, 4/5 and 5/6), the error performance and coding gains can be effectively improved even when the iteration numbers are reduced.

碩士
元智大學
資訊傳播學系
96
In order to produce digital TV programs, terrestrial broadcasting companies must not only spend more budget and effort to upgrade the equipments and internal systems, but also introduce brand new concepts into program production, transmission, and audiences’ viewing habits. Due to the diversity of audiences’ viewing habits and the increase needs of digital contents, this study is going to focus on how to use digital contents effectively to improve marketing abilities and accessibilities. The objective of this study is to develop a model for value-added service of digital content for the terrestrial broadcasting companies. This study then takes a program named “The Grace Fruit in Taiwan” from Formosa TV as an example to examine the effects of implementation of value-added service of digital content on broadcasting companies and to develop several recommendations for those companies. The findings of this study indicate that the terrestrial broadcasting companies might need to develop their digital content on the basis of “content is service, and service is content.” Companies should provide high quality digital content to increase their reputation. By utilizing modular contents and categorizing the digital contents by the attributes of threshold, central, variety-enhancing, and plus-only, the company will be able to utilize the same contents to its fullest potential. The study recommends Formosa TV to focus on topics such as entertainment, information (knowledge), and health when developing their program’s content. Furthermore, the companies should provide specialized training for their personnel, and establish new media departments that employ the cross-media workers.

碩士
國立中山大學
電機工程學系研究所
93
The topic of this thesis presents a digital front end (DFE) of the digital video broadcasting over terrestrial (DVB-T). The DVB-T system is similar to most of the prior digital communication system. It is roughly divided into two major parts, one for channel coding/decoding, and the other for modulation/demodulation. The thesis is mainly focused on the DVB-T digital video broadcasting demodulation part of the receiver and the integration of a complete digital front demodulation system. The major operational processor of the DFE is a 2K/8K dual-mode FFT processor, which has been implemented by the TSMC ( Taiwan Semiconductor Manu-facturing Company ) 0.35um 2P4M CMOS process technology to justify the simulation results as well as the correctness of the proposed architecture.

碩士
元智大學
資訊傳播學系
96
Terrestrial TV has been launched since 1930 and made a great impact on human life style, it not only become the source of entertainment and information for every family, but also become a necessity of life gradually. Since 1990, the internet started to be well developed, it also become an important part of life inch by inch with the convenience of message transmission. In the era of digital convergence, digital television, internet and telecommunications, three majors of network, make cross-border of access channel and services because of bandwidth upgrade and video compression technology developed. Internet can provide cross-media services such as TV programs, which makes television broadcasters have to face the media revolution. Therefore, how to find out correct competitive strategy to enhance the value and function of terrestrial television stations in the media industry has become a very important issue. This paper will focus on how the major terrestrial TV industry finds the right competitive strategy in the digital convergence era. This study documents is under the depth interviews and analysis of data collection to Porter’s (1980) five competitive strategy analysis theory of a traditional television’s greatest competitive advantage in the digital convergence. The initial conclusion is that the internal organizations of those terrestrial TV have to make the basic differences, build low-cost and focus on the audio-visual program supply capacity in order to maintain competitive advantage and position. In addition, they also have to develop multi-platform cooperation services in order to further the pursuit of growth and diversification operation.

碩士
國立中央大學
通訊工程研究所
93
ABSTRACT Viterbi algorithm is the well-known and efficiently maximum likelihood decoding algorithm applied to decode convolutional code. In this discussion, it concentrates on the standard of punctured convolutional encoder in DVB-T system. To design and implement a Viterbi decoder agreed with the decoding throughput which limited by the system, on the other hand, to research the soft-decision method for decoding process with the result in promoting the bit error rate！ The way used to soft-decision is by the minimum distance algorithm . Bit branch metrics have different value if the quantized level is not the same for soft-decision decoding. The analysis is focusing on the performance of soft-decision quantized level Q=8 and Q=16 and hard-dec ision and a basis for the coming IC design of Viterbi decoder. In the implementation issue, full parallel architecture and modulo normalization are used to save the source and decoding throughput, then the 3-pinter even block method is used to trace back and decoding the data. At the last, we implement the Viterbi decoder by above-mentioned ways and the soft-decision quantized level is Q=16.

碩士
國立中央大學
通訊工程研究所
93
Many digital signaling applications in broadcasting use Forward Error Correction, a technique in which redundant information is added to the signal to allow the receiver to detect and correct errors that may have occurred in transmission. Many different types of code have been devised for this purpose, but Reed-Solomon codes have proved to be a good compromise between efficiency and complexity. Reed-Solomon error correction has several applications in broadcasting, in particular forming part of the specification for the ETSI digital terrestrial television standard, known as DVB-T. In this thesis, we applied the specification for the ETSI digital terrestrial television standard(DVB-T) to realize the hardware implementation of Reed-Solomon decoder. Using Verilog Hardware Description Language and simulating by software “Modelsim” to confirm our program of RS(204,188,8) are fine and can correct errors which result from bad channel. Then, synthesizing logic-RTL by Synplify.

A research report is submitted in partial fulfilment of the requirements for the degree of Master of Arts in ICT Policy and Regulation to the Faculty of Humanities, University of the Witwatersrand, 2016
South Africa has a nascent community television sector, which is legislated as a tier of broadcasting. This sector is important in deepening democracy, creating access to information, giving communities the space to share information, and expanding media ownership to communities beyond the public and commercial television broadcasting sectors. Since 2007, when Soweto TV was the first community television station to be licensed, the processes towards migrating analogue to digital terrestrial television have been beset with delays and the experience of the community TV sector with respect to this migration have been not well understood. The conceptual-analytical framework for this historical study of the period 2007 to 2014 drew on the key themes of sector and institutional governance including the effectiveness of policy and regulation, technological advancement, content and services. Using a constructivist methodology the key documents pertaining to broadcast digital migration were reviewed and interviews were conducted with three community TV stations, Soweto TV, Bay TV and Cape Town TV, as well as with the policy-maker, the regulator and sector experts. The findings revealed that the community television (CTV) sector was faced with problems of sector and institutional governance not being effectively addressed in legislation and regulation, stagnation as a result of lack of spectrum in the analogue television-broadcasting dispensation and limitations on content provision. Using McConnell’s 2010 framework, analysis of the data led to the conclusion that the DTTM programme has failed with respect to the community TV sector. Advances for the CTV sector will require revision to legislation and future regulation to guide the governance of the CTV sector and the digital terrestrial television migration should be concluded without further delay, in order to enable the sector to grow. Although CTV stations are providing content to communities, the opportunity for them to make a greater impact, if digital terrestrial television (DTT) is finally launched, should be prioritised as the new technology can provide them with the scope to expand their content offerings.
MT2017

no
This work presents a novel broadband monopole antenna for digital video broadcastingterrestrial (DVB-T) application. The proposed antenna consists of a grating patch and a concave rectangular ground plane with defected ground plane, and the Multiple Split-Ring Resonator (MSRR). The added part in the ground plane and the meta-material are used to enable the antenna height reduction for fixed ranges of operating frequency. The antenna can operate from 468 MHz to 894 MHz frequency range corresponding to 62.5% of impedance bandwidth for |S11|<-7.5 dB. Details of the proposed antenna designs and experimental results of the constructed prototypes are presented and discussed.
The full text cannot be displayed due to the publisher's copyright agreement.

This is an exploratory study conducted to assess the way in which social media could enhance the experience for audiences of the South African Broadcasting Corporation (SABC) television drama. This study focused on Facebook and Twitter since they are two of the top five social media networks that are popular in the country and which have the potential to offer television more mileage in terms of communicating with its audience and extending its reach. The guiding theory for this study was uses and gratifications theory. This theory was employed to assist in assessing the opportunities that exist for SABC television drama, as well as to assess the ways in which the audience believe social media could be helpful in interacting with SABC television drama. The results for this study are interesting in that the majority of respondents believed that having a hashtag on screen during a drama broadcast would help to increase interactivity with the programme, as it could help direct audiences to the correct interactive space for that programme and they would be able to share their ideas and comments on the drama directly with the producers, making feedback immediate. It was interesting to note that the respondents believed that they could interact with SABC television drama for information relating to the story. The findings suggest that SABC television drama needs to actively adopt social media in its programmes for maximum interaction. There is also the need for an understanding of how they Facebook and Twitter could be embedded in SABC drama.
Communication Science
M.A. (Communication Science)

Com o crescimento das tecnologias da informação e comunicação (TICs), a Televisão Analógica Terrestre se tornou obsoleta frente às tecnologias entrantes, por não oferecer serviços tecnológicos de qualidade aos seus utilizadores. Assim, faz-se impreterível a migração das Emissoras de Televisão do sistema analógico para o digital. Nesse contexto, a investigação visou a o estudo de viabilidade, nos planos tecnológico e econômico-financeiro, para a implantação da Televisão Digital Terrestre (TDT), estudo esse suportado num modelo criado para esse efeito. Para tanto, a investigação levantou, através de uma pesquisa bibliográfica, documental e estudo de caso, aspectos tecnológicos e de gestão referentes à TDT, tendo como foco a realidade brasileira. Esses levantamentos serviram de subsídio para a formação das alternativas tecnológicas possíveis na implantação da TDT e também para a concepção dos modelos de negócio utilizando o datacasting. As análises efetuadas mostraram-se eficientes na escolha da tecnologia e dos modelos de negócios. Definidos os modelos, realizou-se uma análise econômica e financeira, a qual mostra que os modelos de negócios através do datacasting e com as configurações tecnológicas utilizadas são economicamente viáveis. A solução proposta está consubstanciada no modelo formulado, o qual resulta da análise crítica dos modelos estudados, permitindo assim, responder à problemática e ao problema de investigação e fundamentar a viabilidade tecnológica e econômicofinanceira relacionada com o objeto e objetivos desta investigação. O modelo permitiu, também, evidenciar que, além da interação com o espectador, a TDT constitui um poderoso meio de distribuição de dados e abre novas frentes de pesquisa nesta área de conhecimento.
The increased development of information and communication technologies (ICTs) turned Analog Terrestrial Television obsolete when compared to new coming technologies, as it cannot provide quality technological services to its users. Thus, the migration of analog Television Stations to digital is imperative. In this context, this research aimed at the feasibility study, in the technological and financial economic plans, for the Digital Terrestrial Television (DTT) implantation and it was supported by an appropriate model that was developed. This model took into account a deep literature review, where different case studies, including technological and management aspects related to DTT, were analysed and adapted to the Brazilian reality. These studies were considered for the possible formation of alternative technologies in the deployment of DTT and also for the design of business models using datacasting. This analysis was effective for the selection of the adopted technological and business models. After defining the proposed models, an economic and financial analysis was performed, which shows that the business models for datacasting, with the technological configurations used, are economically viable. The proposed solution is consolidated in the model formulated, which results from a critical analysis of the studied models, thus, to respond to the problematic and research problem identified and to support the technological, financial and economic feasibility related to the purpose and objectives of this research. The proposed solution also shows that, besides the possibility of interaction with viewers, DTT is a powerful system for data distribution that opens a wide range of new opportunities in this field.

Diploma thesis examines the form of television market in the age of digitalized terrestrial broadcasting with regard to the extent to which there can be found genre innovations, wider scale of origin countries and the placement of its own or foreign programme premieres. For this purpose, it concentrates on eight new digital channels distributed in terrestrial network; available nationwide, not monothematic and having audience share of at least around one percent. In the theoretical part, there is briefly summarized the history of the digitalization process in the Czech Republic, there are profiles of examined TV channels and thesis also presents extinct or minor digital channels shortly. For research purpose, thesis uses quantitative analysis methodology; it allows to explore larger amount of materials and achieve the general knowledge. The results consist of the comparison between the eight channels in three categories, description of the evolution of programme in the course of the time compared to the first month of broadcasting and contextual contrast using partial analysis of broadcasting of main and then only analogue available channels . The major positive aspect of the new channels is a higher degree of ambiguity genre. However, U.S. still holds important role as origin country of the programmes.

Desde o inicio da utilização de radares pelos militares que é conhecido o facto da vulnerabilidade da localização do transmissor quando se encontra a transmitir. Não só por este caso, mas também pelo pelo custo elevado de um transmissor, o radar passivo apresenta-se como uma solução ideal a todos estes problemas. No entanto, como tudo, tem as suas desvantagens, realçando não se controlar o sinal que é transmitido pelo iluminador de oportunidade e este não estar otimizado para sistemas de radar, o que no final, implica um processamento mais complexo. Este conceito de radares passivos não é uma ideia recente. A primeira experiência realizada remonta ao ano de 1935, quando Robert Watson-Watt usara um iluminador de oportunidade de onda curta radiada do BBC Empire transmitter em Daventry para detetar um bombardeiro Heyford a uma distância de 8 km. Porém, o primeiro radar passivo foi desenvolvido uns anos depois pelos alemães, denominado Klein Heidelberg. A presente dissertação objetiva analisar e ampliar o conhecimento existente na literatura através do estudo de sistemas de radar passivo para a deteção de alvos, usando como iluminador de oportunidade, a televisão digital terrestre, Digital Video Broadcasting - Terrestrial (DVB-T) e, simultaneamente, elaborar um trabalho de desenvolvimento sobre radares passivos, processamento de sinal nos mesmos, teoria de antenas e formação de imagem utilizando radares passivos. Esta dissertação tem ainda como objetivo o desenvolvimento de um sistema de radar passivo que permita a deteção de alvos utilizando DVB-T. Em jeito de conclusão e em função dos resultados obtidos pretende-se discutir possíveis cenários de implementação na Marinha Portuguesa.
Since the beginning of the use of radars by the military it is known the fact of vulnerability in the location of the transmitter when it is operating. It is not only by this specific reason, but also because of the pollution of the electromagnetic spectrum or the high cost of a transmitter, the passive radar is an ideal solution to all these problems. However, like everything, it has its disadvantages, such as the signal that is transmitted by the illuminator of opportunity is not controlled and it is not optimized for radar systems, which in the end, implies a more complex processing. The concept of passive radars is not a recent idea. In fact, the first experiment carried out dates back to the year of 1935 when Robert Watson-Watt used a BBC Empire transmitter shortwave illuminator of opportunity in Daventry to detect a Heyford bomber at a range of 8 km. However, the first passive radar was developed a few years later by the Germans, called Klein Heidelberg. This dissertation has as main objective the research of a passive radar system, using DVB-T as an illuminator of opportunity and, simultaneously, to develop a development work on passive radars, its signal processing, basic theory of antennas and passive radars for image formation. This work has also an objective of developing a passive radar system using DVB-T. As a conclusion and based on the results obtained, it is intended to discuss possible implementation scenarios in the Portuguese Navy.

This thesis describes digital television transition in the United States. Its goal is to introduce the way how digital television broadcasting in the United States was formed and analog broadcasting was switched off, and how these changes affected American television market and usage of broadcasting spectrum. In the first part I explain a context in which American television market has been formed and has developed until the beginning of 1990s, when the debate about digital television broadcasting commenced. Reason for a development of the new television norm was a desire to broadcast in high definition. Establishment of ATSC norm is explained in 4th chapter. Following chapter describes how digital television coverage grew and what the expenses were for viewers. The thesis then describes spectrum auctions and changes in the television market which digital television transition brought. When the transition ended need for a new debate about television emerged because current norm is becoming obsolete and did not allow broadcasting in ultra high definition. This lead to the development of ATSC 3.0 norm which allows broadcasting more programs in terrestrial television broadcasting and allows expanding terrestrial broadcasting to other mobile devices.