Littérature scientifique sur le sujet « Digital Terrestrial TV Broadcasting »

In the second decade of the 21st century, the interconnection and even interdependence between the qualitative characteristics of modern screen produce and screen arts in general and those of rapidly developing innovative technologies becomes increasingly obvious. tte affinity of different academic problems pertaining to the analysis of film industry, in humanities and science in particular, raises a lot of questions. One of them deals with revealing the factors necessary for the international recognition of a fundamental project and its subsequent implementation. This issue is illustrated in the article by the history of terrestrial television which has evolved from analogue broadcasting to digital, multi-program, interactive TV.

Russian TV industry is now undergoing a stage of impetuous reforming. Alongside with the introduction of the digital platform of nation-wide terrestrial broadcasting with free analogue programs other demanded segments of TV market - cable and satellite TV, IPTV, webcasting, mobile TV - are rapidly developing. The article surveys the International Exhibition CSTB’2012, (organized by MIDEXPO and Russian Association of Cable Broadcasting) as an example of the dynamics of the processes in Russian television.

Perkembangan perkotaan yang pesat dengan pembangunan fisik berupa gedung bertingkat baik berupa hotel, perkantoran maupun apartemen akhir-akhir ini berakibat juga terhadap perambatan gelombang radio diudara bebas .Media televisi terestrial tidak berbayar ( free to air ) yang menggunakangelombang radio jalur Ultra High Frequency (UHF), pada frekuensi sekitar 600 MHz dengan Sistem Penyiaran (Broadcasting) analog yaitu Phase Alternating Line (PAL), akan terasa dampaknya akibat gedung pencakar langit tadi, karena perambatan gelombang yang cenderung mendatar diatas permukaan bumi (Ground Wave). Secara otomatis di daerah-daerah perkotaan yang dikelilingi gedung bertingkat sulit mendapatkan tayangan secara langsung (direct broadcast) dari transmisi terrestrial free to airatau secara teknis dikenal dengan blank spot area.Kondisi tersebut memberikan kesempatan untuk televisi berbayar (Pay TV ) untuk memenangkan persaingan dalam menggaet penonton dengan melakukan penetrasi penjualan layanan pada daerah tersebut , baik untuk Pay TV berbasis satelit , cable maupun digital terrestrial.

The main objective of the study was to analyse the particularities of transition from terrestrial to digital format of the television in Ukraine. This objective was accomplished with the help of the following research methods: the method of analysis was applied to select the subjects of digitalization and to determine their role in the overall process; historical method was used to reconstruct the chronological order of events in transition to the digital television in Ukraine and in the world; the method of analogy was applied to determine the prospects of digital broadcasting development in Ukraine. Results and Conclusions. The process of transition from analogue to digital format of television in Ukraine has been lasting for 10 years. This is due to some problems at the state level (the conflict in competences of the responsible state agencies, the lack of a single decision-making centre, the lack of influence on the monopoly provider), at the TV content market (the unfounded costs of territory coverage with analogue signal, the lack of digital broadcasting licenses for many regional and local channels), and at the service provider’s level (the monopoly position of the existing provider, the absence of grounded calculation for territory coverage by the current national network). This set of problems leads to ambiguity in digital television perception within the domestic market, and costs Ukraine in its international public image due to failure to fulfil the Geneva 2006 agreement. The new relationships and patterns in transition from terrestrial to digital format of the television broadcasting in Ukraine were discovered in this study. It is grounded that the coordinated and efficient work of responsible state agencies is needed to solve the existing problems and to implement transition to digital broadcasting in Ukraine. The construction of alternative digital networks and the licensing of new digital networks providers are also needed, as well as the state assistance in providing digital TV devices to vulnerable groups of population and proper information campaign of the need to transit to digital TV.

<span style="font-size: 9pt; font-family: 'Times New Roman', serif;">DVB-T2 (Digital Video Broadcasting – Second Generation Terrestrial) is one of the latest technical standards being developed by the DVB Project for DTT (Digital Terrestrial Television). It is also known as digital broadcasting trough terrestrial system since 2006 and is an extension of the DVB-T system as a second generation program to improve efficiency of the total system. It is important to perform a research on the performance of DVB-T2 because Malaysia has launched the free-to-air digital TV project since 2016 hence there is a need to know how well the signal is being received by viewers. This research focuses on a DVB-T2 transmission process which involve the transmission from Menara Kuala Lumpur transmitter to receivers located at 100 different locations. The performance of DVB-T2 can be determined by measuring the field strength, MER (Module Error Ratio) and BERaLDPC (Bit Error Rate after Low Density Parity Check decoder), and then a comparison between DVB-T and DVB-T2 systems can be made. Equipments involved in the measurement are indoor antenna, distribution amplifier, waveform monitor, field strength meter, DVB-T2 decoder and TV set as the receiver. Results are recorded in Microsoft Excel and analyzed using MATLAB software. The result of the measurement shows92% of the test points had higher reading than the baseline value which means better reception of digital TV signal is delivered to the location.Comparison between DVB-T and DVB-T2 performance shows that field strength of the DVB-T2 system is slightly higher by 1.5 % – 3.8 % from DVB-T</span><p class="MsoNormal"><span style="font-size: 16.0pt; line-height: 107%; mso-bidi-font-style: italic;">Measurement of digital video broadcasting-second generation terestrial (DVB-T2) signal in Kuala Lumpur, Malaysia</span></p>

In many countries, terrestrial broadcasting is the main delivery medium for television. In this paper, we propose a small-volume practical receiving antenna. Our design consists of a linear array of three vertically placed patch antennas which increase antenna gain. The antenna has a double-dielectric substrate (FR4 + air) in order to increase efficiency and bandwidth. In this paper, we also discuss simulations and practical results, and demonstrate that the proposed double-dielectric microstrip antenna is a viable design choice for digital terrestrial TV (DTT) reception. The designed antenna reached a gain of 10.5 dBi at the desired central frequency of 754 MHz.

A novel internal antenna has been developed for indoor reception of UHF terrestrial digital TV broadcasting. The overall size of some configurations of the new antenna is less than 2 cm3, and its weight is less than 1 gm. It is made of a flexible material that can be bent or folded and shaped in any form. It is an unbalanced resonant antenna that does not need a matching circuit. The new antenna can be fully embedded inside TV sets or portable computers. It has a bandwidth of about 68%. Thus, it can also cover the bands of GSM and CDMA, which is advantageous in case of portable computers. The new antenna is linearly polarized. It can be easily modified to be dual polarized by combining two orthogonal antennas with one or two feed points. The overall efficiency of some configurations of the new indoor digital TV receiving antenna is more than 80%, and its peak gain is about 2 dBi over the whole UHF band. The peak gain can be increased to more than 5 dBi by adding EBG (electromagnetic bandgap) structures. The EBG structure also increases the efficiency to around 90%.

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.

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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.

Orientador: Ana Silvia Lopes Davi Medola
Co-orientador: Guido Lemos de Souza Filho
Banca: Wilson Massashiro Yonezawa
Banca: Fernando Antonio Crocomo
O "Programa de Pós-Graduação em Televisão Digital: informação e conhecimento" capacita profissionais para atuarem em televisão digital nas três áreas: comunicação, educação e tecnologia
Resumo: O contexto tecnológico e convergente proposto pela integração de diferentes plataformas e dispositivos digitais provoca uma reconfiguração dos discursos e estimula a geração de novos modelos comunicacionais. Estes modelos são operacionalizados a partir de lógicas colaborativas e participativas que surgem com a inserção de novas ferramentas caracterizadoras de diálogos e interações entre a audiência e os produtores de conteúdos. Neste cenário há um intercâmbio entre os papéis desempenhados pela audiência e produtos, desconstruindo um antigo esquema comunicacional em que os define como "receptor e emissor". A reconfiguração de diálogos e papéis da comunicação televisiva é possibilidade no contexto de implementação da TV digital interativa no Brasil. As novas possibilidades discursivas no campo jornalístico ganharam uma dimensão a partir da Internet com o desenvolvimento da Web 2.0, que permitiu a realização de projetos colaborativos. Na Web 2.0 o jornalismo foi estruturado através dos aspectos de personalização, cooperação e colaboração que são modelados pelas bases comunitárias de produção. Esta prática comunitária permitiu diferentes vertentes da prática jornalística, que foram denominadas de jornalismo open source, user-generated content e prosumersm, citizen journalism e participatory journalism. Nestes modelos de jornalismo a audiência é a principal produtora e consumidora da notícia. As próprias pessoas refletem, elaboraram e divulgam informações que vivenciaram cotidianamente. Entretanto, a apropriação e manutenção da produção jornalística colaborativa recebem uma força essencial com estruturação desta prática a partir de redes sociais. A formação destas redes possibilita a organização comunitária de grupos que compartilham os mesmos interesses e anseios. Dentro deste contexto, a presente pesquisa propõe a modelagem de ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The technological context and convergent proposed by integrating different platforms and digital devices causes a reconfiguration of the discourses and stimulates the generation of new models of communication. These models are operationalized from collaborative and participatory logic that arise with the introduction of new tools for characterizing dialogue and interaction between audience and content producers. In this scenario there is an interchange between the roles played by the audience and producers, desconstructing and old communication scheme that defines them as "receiver" abd "sender". The reconfiguration of dialogues and roles of television communication is possible in the context of implementation of interactive digital TV in Brazil. The new discursive possibilities in the journalistic field have gained a dimension from the Internet with the development of Web 2.0, which allowed the realization of collaborative projects. Web 2.0 journaslism has been structured through the aspects of personalization, cooperation and collaboration that are shaped by community-based production. This community practice allowed different aspects of journalistic practice, which were called open source journalism, user-generated content and prosumersm, citizen journalism and participatory journalism. In these models of journalism, audience is a major producer and consumer of news. The people themselves reflect and disseminate information producing a daily experience. However, ownership and maintenance of collaborative news production receives an essential force in the structuring of this practice from social networks. The formation of these networks allows the community organizing groups to share the same interests and desires. Within this context, this research proposes the modeling of a collaborative process of news production for interactive digital TV from Web 2.0
Mestre

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This paper analyzes the major challenges that the new technologies and changes in the post-industrial society are imposing on the Brazilian digital TV and its business model and provides an analysis of how this new configuration of the information society affects the business model of opened television networks in Brazil in the transitional moment from analog to digital. It analyzes the business model before, analog TV, based on the thirty-second commercial and points to difficulties that the old model is adopted in contexts of political, social and economic affairs that takes place in the new Brazilian society. Still, it seeks to demonstrate that other factors contribute to the migration of audience to other platforms for content distribution, refuting the common view that access to broadband internet is the main cause of falling ratings. This study uses an extensive bibliography that goes beyond the specific field of communication and expands the vision of the television industry in Brazil opened by listing weaknesses of the sector and point to possible strategies for the Brazilian television that can adapt to the new structure of communication which is forming in our country.
O presente trabalho analisa os importantes desafios que as novas tecnologias e as transformações na sociedade pós-industrial estão impondo à TV digital brasileira e ao seu modelo de negócios. Tem como principal objetivo realizar uma reflexão sobre a viabilidade financeira das emissoras abertas com a chegada da TV digital. Para tanto, analisa o modelo de negócios anterior, da TV analógica, baseado nos comerciais de trinta segundos e como esta forma poderá ser afetada inviabilizando a estrutura de produção e distribuição de conteúdo pelas emissoras abertas digitais. Ainda, busca evidenciar demais fatores que contribuem para a migração da audiência para outras plataformas de distribuição de conteúdo, refutando o senso comum de que o acesso à internet banda larga é a principal causa da queda dos índices de audiência. Este estudo se utiliza de uma ampla bibliografia que extrapola o campo específico da Comunicação e amplia o olhar sobre a indústria televisiva aberta no Brasil, enumerando fragilidades do setor e apontando possíveis estratégias para que a televisão brasileira possa se adaptar à nova estrutura da comunicação que está se formando em nosso país.

Digital television is one of the biggest broadcasting media available. All over the world television companies are rearranging their broadcasting from analogue to digital transmission. Former standard disagreements in the analogue era have lead to an agreement of one common European standard for digital television. Countries like USA and Japan have their own similar standards.

The report consists of two objectives; a survey of the most commonly used standards for digital television today and the construction of a prototype receiver for the second generation satellite DVB-standard.

A thorough literature study and careful design resulted in a fully functioning system. Measurements performed on the DVB-S sections gave exemplary results. Comparing these results with corresponding measurements performed on the DVB-S2 section showed much better performance for DVB-S2 with the same code rates. This shows some of the advantages of the new standard and proving the coding theory right. New coding algorithms make it possible to transmit more information on noisier channels of inferior quality. In laymen’s words; DVB-S2 gives a better picture and more television channels on the same satellite compared to DVB-S.

This thesis explores the problem of compatibility between generations in the field of Digital Television, and proposes solutions to this problem. Since its inception, the DTV has been under development without taking into account the ability to continue receiving broadcasts with legacy equipment when a new generation is introduced. Therefore, when it comes time to introduce a new technology, a simulcast solution is usually used. The study carried out in this thesis explains the reasons why a traditional simulcast is a problem. As a concrete study example, the case of the transition from SD MPEG-2 to HD H.264 broadcasts according to the DVB-T standard is analyzed. And how this problem unnecessarily extends the transition periods between generations. In this way it postulates that one way to promote the development of new generations of Digital Television is precisely to shorten transition times. In order to facilitate the transition to a new generation, different technical solutions have been studied and developed that provide a certain degree of compatibility between generations. The results obtained conclude that it is not only feasible, but also desirable, to incorporate inter-generational compatibility solutions in Digital Television standards. Using the techniques described here, and others listed as future work, it would be possible for new standards and generations to incorporate this necessary capability.
Esta tesis explora el problema de la compatibilidad entre generaciones en el área de la Televisión Digital, y propone soluciones a ese problema. Desde su inicio, la TVD se ha ido desarrollando sin tener en cuenta la capacidad de seguir recibiendo emisiones con equipos antiguos cuando se introduce una nueva generación. Por lo tanto, cuando llega el momento de introducir una nueva tecnología, se suele utilizar una solución de emisión simultánea o simulcast. El estudio realizado en esta tesis explica las razones por las que un simulcast tradicional es un problema. Como ejemplo de estudio específico, se analiza el caso de la transición desde emisiones SD MPEG-2 a HD H.264 utilizando el estándar DVB-T. Y cómo esta dificultad alarga innecesariamente los períodos de transición entre generaciones. En esta línea se postula que una forma de promover la implantación de nuevas generaciones de Televisión Digital es precisamente acortando los tiempos de transición. Para facilitar la transición a una nueva generación, se han estudiado y desarrollado diferentes soluciones técnicas que proporcionan un cierto grado de compatibilidad entre generaciones. Los resultados obtenidos concluyen que no sólo es factible, sino también deseable, incorporar soluciones de compatibilidad intergeneracional en los estándares de Televisión Digital. Utilizando las técnicas aquí descritas, y otras enumeradas como trabajos futuros, sería posible que los nuevos estándares y generaciones incorporaren esta característica necesaria.

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

CAPES
É um interesse permanente das entidades de teledifusão conhecer a região geográfica servida por suas emissões. Modelos computacionais podem fornecer informações detalhadas sobre a área coberta, ao implementar variados métodos de predição baseados em normas e recomendações. Enquanto tais métodos computacionais são indispensáveis à tomada de decisão dos órgãos reguladores, medir o sinal após sua implementação é atividade imprescindível para validar as predições, e para identificar precisamente áreas sem cobertura e orientar na sua solução. Analisar os diversos aspectos envolvidos, e validar uma metodologia prática para conhecer a cobertura real de um sistema de TV digital é o objetivo deste trabalho.
Knowing the exact region served by a broadcasting station is a permanent interest. Computer models can produce detailed maps of the covered area, by implementing several prediction methods prescribed in specific regulations. While such computer methods are essential to the decision-making process of the regulatory boards, some field-work is still required to validate the predictions, as well as to investigate situations that may give rise to reception difficulties. The analysis of the several aspects involved, and the validation of a practical method for assessing the true coverage of the digital TV system adopted in Brazil is the purpose of this work.