Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast

Tesis por compendioDesde 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/10251/105559TESISCompendi

Self-concatenated coding for wireless communication systems

In this thesis, we have explored self-concatenated coding schemes that are designed for transmission over Additive White Gaussian Noise (AWGN) and uncorrelated Rayleigh fading channels. We designed both the symbol-based Self-ConcatenatedCodes considered using Trellis Coded Modulation (SECTCM) and bit-based Self- Concatenated Convolutional Codes (SECCC) using a Recursive Systematic Convolutional (RSC) encoder as constituent codes, respectively. The design of these codes was carried out with the aid of Extrinsic Information Transfer (EXIT) charts. The EXIT chart based design has been found an efficient tool in finding the decoding convergence threshold of the constituent codes. Additionally, in order to recover the information loss imposed by employing binary rather than non-binary schemes, a soft decision demapper was introduced in order to exchange extrinsic information withthe SECCC decoder. To analyse this information exchange 3D-EXIT chart analysis was invoked for visualizing the extrinsic information exchange between the proposed Iteratively Decoding aided SECCC and soft-decision demapper (SECCC-ID). Some of the proposed SECTCM, SECCC and SECCC-ID schemes perform within about 1 dB from the AWGN and Rayleigh fading channels’ capacity. A union bound analysis of SECCC codes was carried out to find the corresponding Bit Error Ratio (BER) floors. The union bound of SECCCs was derived for communications over both AWGN and uncorrelated Rayleigh fading channels, based on a novel interleaver concept.Application of SECCCs in both UltraWideBand (UWB) and state-of-the-art video-telephone schemes demonstrated its practical benefits.In order to further exploit the benefits of the low complexity design offered by SECCCs we explored their application in a distributed coding scheme designed for cooperative communications, where iterative detection is employed by exchanging extrinsic information between the decoders of SECCC and RSC at the destination. In the first transmission period of cooperation, the relay receives the potentially erroneous data and attempts to recover the information. The recovered information is then re-encoded at the relay using an RSC encoder. In the second transmission period this information is then retransmitted to the destination. The resultant symbols transmitted from the source and relay nodes can be viewed as the coded symbols of a three-component parallel-concatenated encoder. At the destination a Distributed Binary Self-Concatenated Coding scheme using Iterative Decoding (DSECCC-ID) was employed, where the two decoders (SECCC and RSC) exchange their extrinsic information. It was shown that the DSECCC-ID is a low-complexity scheme, yet capable of approaching the Discrete-input Continuous-output Memoryless Channels’s (DCMC) capacity.Finally, we considered coding schemes designed for two nodes communicating with each other with the aid of a relay node, where the relay receives information from the two nodes in the first transmission period. At the relay node we combine a powerful Superposition Coding (SPC) scheme with SECCC. It is assumed that decoding errors may be encountered at the relay node. The relay node then broadcasts this information in the second transmission period after re-encoding it, again, using a SECCC encoder. At the destination, the amalgamated block of Successive Interference Cancellation (SIC) scheme combined with SECCC then detects and decodes the signal either with or without the aid of a priori information. Our simulation results demonstrate that the proposed scheme is capable of reliably operating at a low BER for transmission over both AWGN and uncorrelated Rayleigh fading channels. We compare the proposed scheme’s performance to a direct transmission link between the two sources having the same throughput

Improved Spectrum Usage with Multi-RF Channel Aggregation Technologies for the Next-Generation Terrestrial Broadcasting

[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[CA] 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/10251/52520TESI

Advanced receivers for distributed cooperation in mobile ad hoc networks

Mobile ad hoc networks (MANETs) are rapidly deployable wireless communications systems, operating with minimal coordination in order to avoid spectral efficiency losses caused by overhead. Cooperative transmission schemes are attractive for MANETs, but the distributed nature of such protocols comes with an increased level of interference, whose impact is further amplified by the need to push the limits of energy and spectral efficiency. Hence, the impact of interference has to be mitigated through with the use PHY layer signal processing algorithms with reasonable computational complexity. Recent advances in iterative digital receiver design techniques exploit approximate Bayesian inference and derivative message passing techniques to improve the capabilities of well-established turbo detectors. In particular, expectation propagation (EP) is a flexible technique which offers attractive complexity-performance trade-offs in situations where conventional belief propagation is limited by computational complexity. Moreover, thanks to emerging techniques in deep learning, such iterative structures are cast into deep detection networks, where learning the algorithmic hyper-parameters further improves receiver performance. In this thesis, EP-based finite-impulse response decision feedback equalizers are designed, and they achieve significant improvements, especially in high spectral efficiency applications, over more conventional turbo-equalization techniques, while having the advantage of being asymptotically predictable. A framework for designing frequency-domain EP-based receivers is proposed, in order to obtain detection architectures with low computational complexity. This framework is theoretically and numerically analysed with a focus on channel equalization, and then it is also extended to handle detection for time-varying channels and multiple-antenna systems. The design of multiple-user detectors and the impact of channel estimation are also explored to understand the capabilities and limits of this framework. Finally, a finite-length performance prediction method is presented for carrying out link abstraction for the EP-based frequency domain equalizer. The impact of accurate physical layer modelling is evaluated in the context of cooperative broadcasting in tactical MANETs, thanks to a flexible MAC-level simulato

Machine Learning in Digital Signal Processing for Optical Transmission Systems

The future demand for digital information will exceed the capabilities of current optical communication systems, which are approaching their limits due to component and fiber intrinsic non-linear effects. Machine learning methods are promising to find new ways of leverage the available resources and to explore new solutions. Although, some of the machine learning methods such as adaptive non-linear filtering and probabilistic modeling are not novel in the field of telecommunication, enhanced powerful architecture designs together with increasing computing power make it possible to tackle more complex problems today. The methods presented in this work apply machine learning on optical communication systems with two main contributions. First, an unsupervised learning algorithm with embedded additive white Gaussian noise (AWGN) channel and appropriate power constraint is trained end-to-end, learning a geometric constellation shape for lowest bit-error rates over amplified and unamplified links. Second, supervised machine learning methods, especially deep neural networks with and without internal cyclical connections, are investigated to combat linear and non-linear inter-symbol interference (ISI) as well as colored noise effects introduced by the components and the fiber. On high-bandwidth coherent optical transmission setups their performances and complexities are experimentally evaluated and benchmarked against conventional digital signal processing (DSP) approaches. This thesis shows how machine learning can be applied to optical communication systems. In particular, it is demonstrated that machine learning is a viable designing and DSP tool to increase the capabilities of optical communication systems

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

Spatial Modulation for Generalized MIMO:Challenges, Opportunities, and Implementation

A key challenge of future mobile communication research is to strike an attractive compromise between wireless network's area spectral efficiency and energy efficiency. This necessitates a clean-slate approach to wireless system design, embracing the rich body of existing knowledge, especially on multiple-input-multiple-output (MIMO) technologies. This motivates the proposal of an emerging wireless communications concept conceived for single-radio-frequency (RF) large-scale MIMO communications, which is termed as SM. The concept of SM has established itself as a beneficial transmission paradigm, subsuming numerous members of the MIMO system family. The research of SM has reached sufficient maturity to motivate its comparison to state-of-the-art MIMO communications, as well as to inspire its application to other emerging wireless systems such as relay-aided, cooperative, small-cell, optical wireless, and power-efficient communications. Furthermore, it has received sufficient research attention to be implemented in testbeds, and it holds the promise of stimulating further vigorous interdisciplinary research in the years to come. This tutorial paper is intended to offer a comprehensive state-of-the-art survey on SM-MIMO research, to provide a critical appraisal of its potential advantages, and to promote the discussion of its beneficial application areas and their research challenges leading to the analysis of the technological issues associated with the implementation of SM-MIMO. The paper is concluded with the description of the world's first experimental activities in this vibrant research field

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