8 research outputs found
Global Throughput Maximization of a Hybrid Unicast-Broadcast Network for Linear Services
International audienceAn exponential growth of the mobile data traffic is expected in future networks. The reason of this growth is related to the increasing popularity of linear services such as mobile TV, live and sports events, which may lead to the delivery of the same contents to a large audience. Recent studies have shown that network cooperation is a promising candidate to deal with such an issue. This paper investigates, from a planning perspective, the optimization of a hybrid unicast/broadcast network for linear services. We introduce an analytical approach with the aim of stating an optimization problem on the hybrid network configuration, namely in terms of the sharing between the unicast and broadcast modes to deliver a particular service. We show by simulation the existence of an optimal operation point which leads to the maximization of the overall throughput of the hybrid network under the constraint of a minimum service success rate
Transmit and Receive Signal Processing for MIMO Terrestrial Broadcast Systems
[EN] Multiple-Input Multiple-Output (MIMO) technology in Digital Terrestrial Television (DTT) networks has the potential to increase the spectral efficiency and improve network coverage to cope with the competition of limited spectrum use (e.g., assignment of digital dividend and spectrum demands of mobile broadband), the appearance of new high data rate services (e.g., ultra-high definition TV - UHDTV), and the ubiquity of the content (e.g., fixed, portable, and mobile). It is widely recognised that MIMO can provide multiple benefits such as additional receive power due to array gain, higher resilience against signal outages due to spatial diversity, and higher data rates due to the spatial multiplexing gain of the MIMO channel. These benefits can be achieved without additional transmit power nor additional bandwidth, but normally come at the expense of a higher system complexity at the transmitter and receiver ends. The final system performance gains due to the use of MIMO directly depend on physical characteristics of the propagation environment such as spatial correlation, antenna orientation, and/or power imbalances experienced at the transmit aerials. Additionally, due to complexity constraints and finite-precision arithmetic at the receivers, it is crucial for the overall system performance to carefully design specific signal processing algorithms.
This dissertation focuses on transmit and received signal processing for DTT systems using MIMO-BICM (Bit-Interleaved Coded Modulation) without feedback channel to the transmitter from the receiver terminals. At the transmitter side, this thesis presents investigations on MIMO precoding in DTT systems to overcome system degradations due to different channel conditions. At the receiver side, the focus is given on design and evaluation of practical MIMO-BICM receivers based on quantized information and its impact in both the in-chip memory size and system performance. These investigations are carried within the standardization process of DVB-NGH (Digital Video Broadcasting - Next Generation Handheld) the handheld evolution of DVB-T2 (Terrestrial - Second Generation), and ATSC 3.0 (Advanced Television Systems Committee - Third Generation), which incorporate MIMO-BICM as key technology to overcome the Shannon limit of single antenna communications. Nonetheless, this dissertation employs a generic approach in the design, analysis and evaluations, hence, the results and ideas can be applied to other wireless broadcast communication systems using MIMO-BICM.[ES] La tecnologÃa de múltiples entradas y múltiples salidas (MIMO) en redes de Televisión Digital Terrestre (TDT) tiene el potencial de incrementar la eficiencia espectral y mejorar la cobertura de red para afrontar las demandas de uso del escaso espectro electromagnético (e.g., designación del dividendo digital y la demanda de espectro por parte de las redes de comunicaciones móviles), la aparición de nuevos contenidos de alta tasa de datos (e.g., ultra-high definition TV - UHDTV) y la ubicuidad del contenido (e.g., fijo, portable y móvil). Es ampliamente reconocido que MIMO puede proporcionar múltiples beneficios como: potencia recibida adicional gracias a las ganancias de array, mayor robustez contra desvanecimientos de la señal gracias a la diversidad espacial y mayores tasas de transmisión gracias a la ganancia por multiplexado del canal MIMO. Estos beneficios se pueden conseguir sin incrementar la potencia transmitida ni el ancho de banda, pero normalmente se obtienen a expensas de una mayor complejidad del sistema tanto en el transmisor como en el receptor. Las ganancias de rendimiento finales debido al uso de MIMO dependen directamente de las caracterÃsticas fÃsicas del entorno de propagación como: la correlación entre los canales espaciales, la orientación de las antenas y/o los desbalances de potencia sufridos en las antenas transmisoras. Adicionalmente, debido a restricciones en la complejidad y aritmética de precisión finita en los receptores, es fundamental para el rendimiento global del sistema un diseño cuidadoso de algoritmos especÃficos de procesado de señal.
Esta tesis doctoral se centra en el procesado de señal, tanto en el transmisor como en el receptor, para sistemas TDT que implementan MIMO-BICM (Bit-Interleaved Coded Modulation) sin canal de retorno hacia el transmisor desde los receptores. En el transmisor esta tesis presenta investigaciones en precoding MIMO en sistemas TDT para superar las degradaciones del sistema debidas a diferentes condiciones del canal. En el receptor se presta especial atención al diseño y evaluación de receptores prácticos MIMO-BICM basados en información cuantificada y a su impacto tanto en la memoria del chip como en el rendimiento del sistema. Estas investigaciones se llevan a cabo en el contexto de estandarización de DVB-NGH (Digital Video Broadcasting - Next Generation Handheld), la evolución portátil de DVB-T2 (Second Generation Terrestrial), y ATSC 3.0 (Advanced Television Systems Commitee - Third Generation) que incorporan MIMO-BICM como clave tecnológica para superar el lÃmite de Shannon para comunicaciones con una única antena. No obstante, esta tesis doctoral emplea un método genérico tanto para el diseño, análisis y evaluación, por lo que los resultados e ideas pueden ser aplicados a otros sistemas de comunicación inalámbricos que empleen MIMO-BICM.[CA] La tecnologia de múltiples entrades i múltiples eixides (MIMO) en xarxes de Televisió Digital Terrestre (TDT) té el potencial d'incrementar l'eficiència espectral i millorar la cobertura de xarxa per a afrontar les demandes d'ús de l'escà s espectre electromagnètic (e.g., designació del dividend digital i la demanda d'espectre per part de les xarxes de comunicacions mòbils), l'aparició de nous continguts d'alta taxa de dades (e.g., ultra-high deffinition TV - UHDTV) i la ubiqüitat del contingut (e.g., fix, portà til i mòbil). És à mpliament reconegut que MIMO pot proporcionar múltiples beneficis com: potència rebuda addicional grà cies als guanys de array, major robustesa contra esvaïments del senyal grà cies a la diversitat espacial i majors taxes de transmissió grà cies al guany per multiplexat del canal MIMO. Aquests beneficis es poden aconseguir sense incrementar la potència transmesa ni l'ample de banda, però normalment s'obtenen a costa d'una major complexitat del sistema tant en el transmissor com en el receptor. Els guanys de rendiment finals a causa de l'ús de MIMO depenen directament de les caracterÃstiques fÃsiques de l'entorn de propagació com: la correlació entre els canals espacials, l'orientació de les antenes, i/o els desequilibris de potència patits en les antenes transmissores. Addicionalment, a causa de restriccions en la complexitat i aritmètica de precisió finita en els receptors, és fonamental per al rendiment global del sistema un disseny acurat d'algorismes especÃfics de processament de senyal.
Aquesta tesi doctoral se centra en el processament de senyal tant en el transmissor com en el receptor per a sistemes TDT que implementen MIMO-BICM (Bit-Interleaved Coded Modulation) sense canal de tornada cap al transmissor des dels receptors. En el transmissor aquesta tesi presenta recerques en precoding MIMO en sistemes TDT per a superar les degradacions del sistema degudes a diferents condicions del canal. En el receptor es presta especial atenció al disseny i avaluació de receptors prà ctics MIMO-BICM basats en informació quantificada i al seu impacte tant en la memòria del xip com en el rendiment del sistema. Aquestes recerques es duen a terme en el context d'estandardització de DVB-NGH (Digital Video Broadcasting - Next Generation Handheld), l'evolució portà til de DVB-T2 (Second Generation Terrestrial), i ATSC 3.0 (Advanced Television Systems Commitee - Third Generation) que incorporen MIMO-BICM com a clau tecnològica per a superar el lÃmit de Shannon per a comunicacions amb una única antena. No obstant açò, aquesta tesi doctoral empra un mètode genèric tant per al disseny, anà lisi i avaluació, per la qual cosa els resultats i idees poden ser aplicats a altres sistemes de comunicació sense fils que empren MIMO-BICM.Vargas Paredero, DE. (2016). Transmit and Receive Signal Processing for MIMO Terrestrial Broadcast Systems [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/66081TESISPremiad
On Transmission System Design for Wireless Broadcasting
This thesis considers aspects related to the design and standardisation of transmission systems for wireless broadcasting, comprising terrestrial and mobile reception. The purpose is to identify which factors influence the technical decisions and what issues could be better considered in the design process in order to assess different use cases, service scenarios and end-user quality. Further, the necessity of cross-layer optimisation for efficient data transmission is emphasised and means to take this into consideration are suggested. The work is mainly related terrestrial and mobile digital video broadcasting systems but many of the findings can be generalised also to other transmission systems and design processes.
The work has led to three main conclusions. First, it is discovered that there are no sufficiently accurate error criteria for measuring the subjective perceived audiovisual quality that could be utilised in transmission system design. Means for designing new error criteria for mobile TV (television) services are suggested and similar work related to other services is recommended.
Second, it is suggested that in addition to commercial requirements there should be technical requirements setting the frame work for the design process of a new transmission system. The technical requirements should include the assessed reception conditions, technical quality of service and service functionalities. Reception conditions comprise radio channel models, receiver types and antenna types. Technical quality of service consists of bandwidth, timeliness and reliability. Of these, the thesis focuses on radio channel models and errorcriteria (reliability) as two of the most important design challenges and provides means to optimise transmission parameters based on these.
Third, the thesis argues that the most favourable development for wireless broadcasting would be a single system suitable for all scenarios of wireless broadcasting. It is claimed that there are no major technical obstacles to achieve this and that the recently published second generation digital terrestrial television broadcasting system provides a good basis. The challenges and opportunities of a universal wireless broadcasting system are discussed mainly from technical but briefly also from commercial and regulatory aspectSiirretty Doriast
Solutions for New Terrestrial Broadcasting Systems Offering Simultaneously Stationary and Mobile Services
221 p.[EN]Since the first broadcasted TV signal was transmitted in the early decades of
the past century, the television broadcasting industry has experienced a series of
dramatic changes. Most recently, following the evolution from analogue to digital
systems, the digital dividend has become one of the main concerns of the
broadcasting industry. In fact, there are many international spectrum authorities
reclaiming part of the broadcasting spectrum to satisfy the growing demand of
other services, such as broadband wireless services, arguing that the TV services
are not very spectrum-efficient.
Apart from that, it must be taken into account that, even if up to now the
mobile broadcasting has not been considered a major requirement, this will
probably change in the near future. In fact, it is expected that the global mobile
data traffic will increase 11-fold between 2014 and 2018, and what is more, over
two thirds of the data traffic will be video stream by the end of that period.
Therefore, the capability to receive HD services anywhere with a mobile device is
going to be a mandatory requirement for any new generation broadcasting system.
The main objective of this work is to present several technical solutions that
answer to these challenges. In particular, the main questions to be solved are the
spectrum efficiency issue and the increasing user expectations of receiving high
quality mobile services. In other words, the main objective is to provide technical
solutions for an efficient and flexible usage of the terrestrial broadcasting spectrum
for both stationary and mobile services.
The first contributions of this scientific work are closely related to the study of
the mobile broadcast reception. Firstly, a comprehensive mathematical analysis of
the OFDM signal behaviour over time-varying channels is presented. In order to
maximize the channel capacity in mobile environments, channel estimation and
equalization are studied in depth. First, the most implemented equalization
solutions in time-varying scenarios are analyzed, and then, based on these existing
techniques, a new equalization algorithm is proposed for enhancing the receivers’
performance.
An alternative solution for improving the efficiency under mobile channel
conditions is treating the Inter Carrier Interference as another noise source.
Specifically, after analyzing the ICI impact and the existing solutions for reducing
the ICI penalty, a new approach based on the robustness of FEC codes is
presented. This new approach employs one dimensional algorithms at the receiver
and entrusts the ICI removing task to the robust forward error correction codes.
Finally, another major contribution of this work is the presentation of the
Layer Division Multiplexing (LDM) as a spectrum-efficient and flexible solution
for offering stationary and mobile services simultaneously. The comprehensive
theoretical study developed here verifies the improved spectrum efficiency,
whereas the included practical validation confirms the feasibility of the system and
presents it as a very promising multiplexing technique, which will surely be a strong
candidate for the next generation broadcasting services.[ES]Desde el comienzo de la transmisión de las primeras señales de televisión a
principios del siglo pasado, la radiodifusión digital ha evolucionado gracias a una
serie de cambios relevantes. Recientemente, como consecuencia directa de la
digitalización del servicio, el dividendo digital se ha convertido en uno de los
caballos de batalla de la industria de la radiodifusión. De hecho, no son pocos los
consorcios internacionales que abogan por asignar parte del espectro de
radiodifusión a otros servicios como, por ejemplo, la telefonÃa móvil, argumentado
la poca eficiencia espectral de la tecnologÃa de radiodifusión actual.
Asimismo, se debe tener en cuenta que a pesar de que los servicios móviles no
se han considerado fundamentales en el pasado, esta tendencia probablemente
variará en el futuro cercano. De hecho, se espera que el tráfico derivado de
servicios móviles se multiplique por once entre los años 2014 y 2018; y lo que es
más importante, se pronostica que dos tercios del tráfico móvil sea video streaming
para finales de ese periodo. Por lo tanto, la posibilidad de ofrecer servicios de alta
definición en dispositivos móviles es un requisito fundamental para los sistemas de
radiodifusión de nueva generación.
El principal objetivo de este trabajo es presentar soluciones técnicas que den
respuesta a los retos planteados anteriormente. En particular, las principales
cuestiones a resolver son la ineficiencia espectral y el incremento de usuarios que
demandan mayor calidad en los contenidos para dispositivos móviles. En pocas
palabras, el principal objetivo de este trabajo se basa en ofrecer una solución más
eficiente y flexible para la transmisión simultánea de servicios fijos y móviles.
La primera contribución relevante de este trabajo está relacionada con la
recepción de la señal de televisión en movimiento. En primer lugar, se presenta un
completo análisis matemático del comportamiento de la señal OFDM en canales
variantes con el tiempo. A continuación, con la intención de maximizar la
capacidad del canal, se estudian en profundidad los algoritmos de estimación y
ecualización. Posteriormente, se analizan los algoritmos de ecualización más
implementados, y por último, basándose en estas técnicas, se propone un nuevo
algoritmo de ecualización para aumentar el rendimiento de los receptores en tales
condiciones.
Del mismo modo, se plantea un nuevo enfoque para mejorar la eficiencia de
los servicios móviles basado en tratar la interferencia entre portadoras como una
fuente de ruido. Concretamente, tras analizar el impacto del ICI en los receptores
actuales, se sugiere delegar el trabajo de corrección de dichas distorsiones en
códigos FEC muy robustos.
Finalmente, la última contribución importante de este trabajo es la
presentación de la tecnologÃa LDM como una manera más eficiente y flexible para
la transmisión simultánea de servicios fijos y móviles. El análisis teórico presentado
confirma el incremento en la eficiencia espectral, mientras que el estudio práctico
valida la posible implementación del sistema y presenta la tecnologÃa LDM c
Potentzia domeinuko NOMA 5G sareetarako eta haratago
Tesis inglés 268 p. -- Tesis euskera 274 p.During the last decade, the amount of data carried over wireless networks has grown exponentially. Several reasons have led to this situation, but the most influential ones are the massive deployment of devices connected to the network and the constant evolution in the services offered. In this context, 5G targets the correct implementation of every application integrated into the use cases. Nevertheless, the biggest challenge to make ITU-R defined cases (eMBB, URLLC and mMTC) a reality is the improvement in spectral efficiency. Therefore, in this thesis, a combination of two mechanisms is proposed to improve spectral efficiency: Non-Orthogonal Multiple Access (NOMA) techniques and Radio Resource Management (RRM) schemes. Specifically, NOMA transmits simultaneously several layered data flows so that the whole bandwidth is used throughout the entire time to deliver more than one service simultaneously. Then, RRM schemes provide efficient management and distribution of radio resources among network users. Although NOMA techniques and RRM schemes can be very advantageous in all use cases, this thesis focuses on making contributions in eMBB and URLLC environments and proposing solutions to communications that are expected to be relevant in 6G
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin
Cooperative Radio Communications for Green Smart Environments
The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin
XIII Jornadas de ingenierÃa telemática (JITEL 2017)
Las Jornadas de IngenierÃa Telemática (JITEL), organizadas por la Asociación de Telemática (ATEL), constituyen un foro propicio de reunión, debate y divulgación para los grupos que imparten docencia e investigan en temas relacionados con las redes y los servicios telemáticos. Con la organización de este evento se pretende fomentar, por un lado el intercambio de experiencias y resultados, además de la comunicación y cooperación entre los grupos de investigación que trabajan en temas relacionados con la telemática.
En paralelo a las tradicionales sesiones que caracterizan los congresos cientÃficos, se desea potenciar actividades más abiertas, que estimulen el intercambio de ideas entre los investigadores experimentados y los noveles, asà como la creación de vÃnculos y puntos de encuentro entre los diferentes grupos o equipos de investigación. Para ello, además de invitar a personas relevantes en los campos correspondientes, se van a incluir sesiones de presentación y debate de las lÃneas y proyectos activos de los mencionados equiposLloret Mauri, J.; Casares Giner, V. (2018). XIII Jornadas de ingenierÃa telemática (JITEL 2017). Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/97612EDITORIA