37 research outputs found

    Estudio del rendimiento de la tecnolog铆a Non-Orthogonal Multiplexing Access para m煤ltiples capas

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    La multiplexaci贸n por divisi贸n en capas (Layered Division Multiplexing, LDM), tambi茅n conocido como acceso m煤ltiple no-ortogonal (Non-Orthogonal Multiple Access, NOMA), es una novedosa t茅cnica de acceso basada en la multiplexaci贸n por potencia. Su uso ha sido aplicado recientemente en el est谩ndar ATSC 3.0, empleando dos capas en la transmisi贸n de la televisi贸n digital terrestre (TDT) para ofrecer servicios m贸viles y fijos. Es decir, hasta ahora se ha limitado la capacidad de LDM en el empleo 煤nicamente de dos capas. El objetivo principal de este proyecto, es extender la investigaci贸n a m煤ltiples capas para evaluar su potencial. Para ello, se ha implementado el an谩lisis te贸rico en una herramienta de simulaci贸n, la cual ha permitido conseguir unos resultados para adquirir una primera idea de su rendimiento. En primer lugar, se presenta tanto la arquitectura definida para el sistema de comunicaciones, como el desarrollo de la herramienta y, a continuaci贸n, las conclusiones obtenidas a partir de las simulaciones realizadas con la herramienta implementada. Finalmente, se presentan nuevos escenarios de aplicaci贸n que podr铆an aprovechar este caso.Geruzatan zatitutako multiplexazioa (Layered Division Multiplexing, LDM), atzipen ez ortogonal anitza (Non-Orthogonal Multiple Access, NOMA)bezala ere ezaguna, potentziarekiko multiplexazioan oinarritutako atzipen teknika berria da. Bere erabilera ATSC 3.0 estandarrean aplikatu berria dalurreko telebista digitalerako,bi geruza erabiliz zerbitzu mugikorrak eta finkoak eskaintzeko[1] [2].Hau da, orain arte LDMren kapazitatea bi geruzatara baino ez da mugatu. Proiektu honen helburu nagusia, ikerketa geruza anitzetara zabaltzea da bere potentzialahausnartzeko. Horretarako, ikerketa teorikoa[3]simulazio-erreminta batean inplementatu da. Lortutako emaitzekin, errendimenduari buruzko lehenengo ideia batera iritsi ahal izanda. Lehenik eta behin, komunikazio-sistemarako definitutako arkitektura zein erremintaren garapena aurkezten da. Ondoren, garatutako erremintarekin lortutako emaitzetan oinarritutako ondorioak. Eta azkenik, garapen honetazbaliatu daitezkeen egoera berriak aurkezten dira.Layer division multiplexing (LDM), also known as non-orthogonal multiple access (NOMA), is a novel access technique based on power multiplexing. Its use has recently been applied in the ATSC 3.0 standard, using two layers in the transmission of digital terrestrial television (DTT) to offer mobile and fixed services [1] [2]. Until now,the capacity of LDM has been limited to theuse of two layers. The main goalof this project is to extendthe research to multiple layers to evaluate its potential. Therefore, the theoretical analysis [3] has been implemented in a simulation tool, which has allowedto obtain the results to acquireafirst idea of its performance. First of all,both,the architecture defined for the communications system andthe development of the toolare presented. Then,the conclusions obtained from the simulations,which have been carried out with the developed tool are presented. Finally, new application scenarios that could benefit ofthis case are proposed

    Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast

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    Tesis por compendioDesde comienzos del siglo XXI, los sistemas de radiodifusi贸n terrestre han sido culpados de un uso ineficiente del espectro asignado. Para aumentar la eficiencia espectral, los organismos de estandarizaci贸n de TV digital comenzaron a desarrollar la evoluci贸n t茅cnica de los sistemas de TDT de primera generaci贸n. Entre otros, uno de los objetivos principales de los sistemas de TDT de pr贸xima generaci贸n (DVB-T2 y ATSC 3.0) es proporcionar simult谩neamente servicios de TV a dispositivos m贸viles y fijos. El principal inconveniente de esta entrega simult谩nea son los diferentes requisitos de cada condici贸n de recepci贸n. Para abordar estas limitaciones, se han considerado diferentes t茅cnicas de multiplexaci贸n. Mientras que DVB-T2 acomete la entrega simult谩nea de los dos servicios mediante TDM, ATSC 3.0 adopt贸 la Multiplexaci贸n por Divisi贸n en Capas (LDM). LDM puede superar a TDM y a FDM al aprovechar la relaci贸n de Protecci贸n 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 m贸viles solo est谩n destinados a obtener la capa superior, conocida como Core Layer (CL). Para no aumentar su complejidad en comparaci贸n con los receptores de capa 煤nica, la capa inferior, conocida como Enhanced Layer (EL), es tratada como un ruido adicional en la decodificaci贸n. Los receptores fijos aumentan su complejidad, ya que deben realizar un proceso de Cancelaci贸n 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 est谩n configuradas con diferentes capacidades de correcci贸n, pero comparten el resto de bloques de la capa f铆sica, incluido el TIL, el PP, el tama帽o de FFT, y el GI. Esta disertaci贸n investiga tecnolog铆as avanzadas para optimizar el rendimiento de LDM. Primero se propone una optimizaci贸n 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 n煤mero de distancias Euclidianas a computar puede aumentar significativamente, conduciendo no solo a receptores fijos m谩s complejos, sino tambi茅n a receptores m贸viles m谩s complejos. A continuaci贸n, se determina la configuraci贸n de piloto ATSC 3.0 m谩s 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 dise帽ados para hacer frente a ecos largos y altas velocidades. La amplitud piloto 贸ptima depende del estimador de canal en los receptores (ej., se recomienda la amplitud m铆nima para una implementaci贸n Wiener, mientras que la m谩xima para una implementaci贸n FFT). Tambi茅n se investiga la potencial transmisi贸n conjunta de LDM con tres tecnolog铆as avanzadas adoptadas en ATSC 3.0: las tecnolog铆as de agregaci贸n MultiRF, los esquemas de MISO distribuido y los de MIMO colocalizado. Se estudian los potenciales casos de uso, los aspectos de implementaci贸n 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 tecnolog铆as avanzadas se consideran admisibles, ya que las mayores demandas ya est谩n contempladas en ATSC 3.0 (ej., una segunda cadena de recepci贸n). Se obtienen ganancias significativas en condiciones de recepci贸n peatonal gracias a la diversidad en frecuencia proporcionada por las tecnolog铆as MultiRF. La conjunci贸n 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 comen莽aments del segle XXI, els sistemes de radiodifusi贸 terrestre han sigut culpats d'un 煤s ineficient de l'espectre assignat. Per a augmentar l'efici猫ncia espectral, els organismes d'estandarditzaci贸 de TV digital van comen莽ar a desenvolupar l'evoluci贸 t猫cnica dels sistemes de TDT de primera generaci贸. Entre altres, un dels objectius principals dels sistemes de TDT de pr貌xima generaci贸 (DVB-T2 i el ATSC 3.0) 茅s proporcionar simult脿niament serveis de TV a dispositius m貌bils i fixos. El principal inconvenient d'aquest lliurament simultani s贸n els diferents requisits de cada condici贸 de recepci贸. Per a abordar aquestes limitacions, s'han considerat diferents t猫cniques de multiplexaci贸. Mentre que DVB-T2 escomet el lliurament simultani dels dos serveis mitjan莽ant TDM, ATSC 3.0 va adoptar la Multiplexaci贸 per Divisi贸 en Capes (LDM). LDM pot superar a TDM i a FDM en aprofitar la relaci贸 de Protecci贸 d'Error Desigual (UEP), ja que tots dos serveis, cridats capes, utilitzen tots els recursos de freq眉猫ncia i temps amb diferents nivells de pot猫ncia. En el costat del receptor, es distingeixen dues implementacions, d'acord amb la capa a decodificar. Els receptors m貌bils solament estan destinats a obtenir la capa superior, coneguda com Core Layer (CL). Per a no augmentar la seua complexitat en comparaci贸 amb els receptors de capa 煤nica, la capa inferior, coneguda com Enhanced Layer (EL), 茅s tractada com un soroll addicional en la decodificaci贸. Els receptors fixos augmenten la seua complexitat, ja que han de realitzar un proc茅s de Cancel路laci贸 d'Interfer猫ncia (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 correcci贸, per貌 comparteixen la resta de blocs de la capa f铆sica, incl貌s el TIL, el PP, la grand脿ria de FFT i el GI. Aquesta dissertaci贸 investiga tecnologies avan莽ades per a optimitzar el rendiment de LDM. Primer es proposa una optimitzaci贸 del proc茅s 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 proc茅s de demapeo de la CL. No obstant a莽貌, el nombre de dist脿ncies Euclidianes a computar pot augmentar significativament, conduint NO sols a receptors fixos m茅s complexos, sin贸 tamb茅 a receptors m貌bils m茅s complexos. A continuaci贸, es determina la configuraci贸 de pilot ATSC 3.0 m茅s 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 redund脿ncia sobre les dades (EL). A partir dels resultats de rendiment, es recomana l'煤s 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 貌ptima dep猫n de l'estimador de canal en els receptors (ex., es recomana l'amplitud m铆nima per a una implementaci贸 Wiener, mentre que la m脿xima per a una implementaci贸 FFT). Tamb茅 s'investiga la potencial transmissi贸 conjunta de LDM amb tres tecnologies avan莽ades adoptades en ATSC 3.0: les tecnologies d'agregaci贸 de MultiRF, els esquemes de MISO distribu茂t i els de MIMO colocalitzat. S'estudien els potencials casos d'煤s, els principals aspectes d'implementaci贸 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 avan莽ades es consideren admissibles, ja que les majors demandes ja estan contemplades en ATSC 3.0 (ex., una segona cadena de recepci贸). S'obtenen guanys significatius per a la capa m貌bil en condicions de recepci贸 per als vianants gr脿cies a la diversitat en freq眉猫ncia proporcionada per les tecnologies MultiRF. La conjunci贸 de LDM amb esquemes MISO distribu茂ts proporciona guanys de rendiment significatius en xarxes SFN per a la capa fixa amb l'esquema d'Alamouti.Garro Crevill茅n, E. (2018). Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast [Tesis doctoral no publicada]. Universitat Polit猫cnica de Val猫ncia. https://doi.org/10.4995/Thesis/10251/105559TESISCompendi

    NOMA-based 802.11g/n: PHY analysis and MAC implementation

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    Industry 4.0 can be considered as the industrial revolution of the current century. Among others, one of its main objectives is the replacement of wired communications by wireless connectivity. The idea is to overcome the main drawbacks of the current wired ecosystem: the lack of mobility, the deployment costs, cable damage and the difficulties with scalability. However, for this purpose, the nature and requirements of the industrial applications must be taken into account, in particular, the proposed communications protocols must support very low loss rates and a strong robustness against failures. This is a very challenging condition due to the nature of the industrial environments (interference with other communication systems, reflections with metallic objects ...). In addition, another characteristic of the industrial applications is the strict requirement related to the latency. On the other hand, industrial applications are not only based on high challenging services, but also exist more flexible requirement applications, such as, web browser, email, video content or complementary information. Those services are considered Best Effort (BE) services. Eventually, in some wireless applications both critical and BE services have to be offered. For those cases, Non-Orthogonal Multiplexing Access (NOMA) technology together with the IEEE 802.11g/n standard is proposed in this document as the physical layer solution. The IEEE 802.11g/n standard has been modified in order to accommodate NOMA schemes, and then, comprehensive simulations are conducted to check and analyze the behavior of the proposed system. It has been determined that through NOMA technology it is possible to obtain better results in certain cases than those achieved in a transmission cases that implements the IEEE 802.11g/n standard in TDM/FDM basis

    Reception performance studies for the evaluation and improvement of the new generation terrestrial television systems

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    270 p.La industria de la TV ha experimentado grandes cambios en las 煤ltimas d茅cadas. Las expectativas cada vez mayores de los espectadores y la reducci贸n del espectro disponible para los servicios de TV han provocado la necesidad de sistemas m谩s robustos de Televisi贸n Digital Terrestre (TDT).El primer intento de cumplir estos requisitos es el est谩ndar europeo DVB-T2 (2009). La publicaci贸n de un nuevo est谩ndar significa el inicio de un proceso de evaluaci贸n del rendimiento del mismo mediante, por ejemplo, estudios de cobertura u obtenci贸n de valores de umbral de relaci贸n se帽al / ruido (SNR). Al inicio de esta tesis, este proceso estaba casi terminado para recepci贸n fija y m贸vil. Sin embargo, la recepci贸n en interiores no se hab铆a estudiado en detalle. Por esta raz贸n, esta tesis completa la evaluaci贸n de DVB-T2 en interiores y define una nueva metodolog铆a de evaluaci贸n optimizada para este escenario.A pesar de que DVB-T2 emplea tecnolog铆as muy avanzadas, el sistema se defini贸 hace casi diez a帽os y desde entonces han aparecido nuevas t茅cnicas avanzadas, como por ejemplo nuevos c贸digos de correcci贸n de errores o la nueva t茅cnica de multiplexaci贸n por divisi贸n en capas (LDM). Estas nuevas t茅cnicas tampoco han sido evaluadas en entornos de interior, por lo que esta tesis incluye el an谩lisis de las mismas evaluando su idoneidad para mejorar el rendimiento de DVB-T2. Adem谩s, se ha comprobado que los algoritmos tradicionales de los receptores TDT no est谩n optimizados para los nuevos escenarios en los que se consideran las se帽ales multicapa y recepci贸n m贸vil. Por esta raz贸n, se han propuesto nuevos algoritmos para mejorar la recepci贸n en este tipo de situaciones.El 煤ltimo intento de hacer frente a los altos requisitos actuales de TDT es el est谩ndar americano ATSC 3.0 (2016). Al igual que con DVB-T2, se necesita proceso completo de evaluaci贸n del sistema. Por ello, en esta tesis se han realizado simulaciones y pruebas de laboratorio para completar el estudio de rendimiento de ATSC 3.0 en diferentes escenarios

    NOMA-based 802.11g/n: PHY analysis and MAC implementation

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    Industry 4.0 can be considered as the industrial revolution of the current century. Among others, one of its main objectives is the replacement of wired communications by wireless connectivity. The idea is to overcome the main drawbacks of the current wired ecosystem: the lack of mobility, the deployment costs, cable damage and the difficulties with scalability. However, for this purpose, the nature and requirements of the industrial applications must be taken into account, in particular, the proposed communications protocols must support very low loss rates and a strong robustness against failures. This is a very challenging condition due to the nature of the industrial environments (interference with other communication systems, reflections with metallic objects ...). In addition, another characteristic of the industrial applications is the strict requirement related to the latency. On the other hand, industrial applications are not only based on high challenging services, but also exist more flexible requirement applications, such as, web browser, email, video content or complementary information. Those services are considered Best Effort (BE) services. Eventually, in some wireless applications both critical and BE services have to be offered. For those cases, Non-Orthogonal Multiplexing Access (NOMA) technology together with the IEEE 802.11g/n standard is proposed in this document as the physical layer solution. The IEEE 802.11g/n standard has been modified in order to accommodate NOMA schemes, and then, comprehensive simulations are conducted to check and analyze the behavior of the proposed system. It has been determined that through NOMA technology it is possible to obtain better results in certain cases than those achieved in a transmission cases that implements the IEEE 802.11g/n standard in TDM/FDM basis

    Reception performance studies for the evaluation and improvement of the new generation terrestrial television systems

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    270 p.La industria de la TV ha experimentado grandes cambios en las 煤ltimas d茅cadas. Las expectativas cada vez mayores de los espectadores y la reducci贸n del espectro disponible para los servicios de TV han provocado la necesidad de sistemas m谩s robustos de Televisi贸n Digital Terrestre (TDT).El primer intento de cumplir estos requisitos es el est谩ndar europeo DVB-T2 (2009). La publicaci贸n de un nuevo est谩ndar significa el inicio de un proceso de evaluaci贸n del rendimiento del mismo mediante, por ejemplo, estudios de cobertura u obtenci贸n de valores de umbral de relaci贸n se帽al / ruido (SNR). Al inicio de esta tesis, este proceso estaba casi terminado para recepci贸n fija y m贸vil. Sin embargo, la recepci贸n en interiores no se hab铆a estudiado en detalle. Por esta raz贸n, esta tesis completa la evaluaci贸n de DVB-T2 en interiores y define una nueva metodolog铆a de evaluaci贸n optimizada para este escenario.A pesar de que DVB-T2 emplea tecnolog铆as muy avanzadas, el sistema se defini贸 hace casi diez a帽os y desde entonces han aparecido nuevas t茅cnicas avanzadas, como por ejemplo nuevos c贸digos de correcci贸n de errores o la nueva t茅cnica de multiplexaci贸n por divisi贸n en capas (LDM). Estas nuevas t茅cnicas tampoco han sido evaluadas en entornos de interior, por lo que esta tesis incluye el an谩lisis de las mismas evaluando su idoneidad para mejorar el rendimiento de DVB-T2. Adem谩s, se ha comprobado que los algoritmos tradicionales de los receptores TDT no est谩n optimizados para los nuevos escenarios en los que se consideran las se帽ales multicapa y recepci贸n m贸vil. Por esta raz贸n, se han propuesto nuevos algoritmos para mejorar la recepci贸n en este tipo de situaciones.El 煤ltimo intento de hacer frente a los altos requisitos actuales de TDT es el est谩ndar americano ATSC 3.0 (2016). Al igual que con DVB-T2, se necesita proceso completo de evaluaci贸n del sistema. Por ello, en esta tesis se han realizado simulaciones y pruebas de laboratorio para completar el estudio de rendimiento de ATSC 3.0 en diferentes escenarios

    Full Stack 5G Physical Layer Transceiver Design for NOMA in Mobile Heterogeneous Networks

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    The Fifth Generation (5G) and Beyond 5G (B5G) wireless networks are emerging with a variety of new capabilities, focusing on Massive Machine-Type Communications (mMTC), enabling new use cases and services. With this massive increment of mMTC along with increasing users, higher network capacity is a must for 5G and B5G. The integration of mMTC with traditional user traffic creates a heterogeneous network landscape. To address this challenge, future network designs must prioritize optimizing spectrum efficiency while meeting diverse service demands. Non-Orthogonal Multiple Access (NOMA) stands out as a promising technology for enhancing both system capacity and operational efficiency in such heterogeneous networks. Due to its non-orthogonal resource allocation, NOMA outperforms Orthogonal Multiple Access (OMA) in spectral efficiency, throughput, and user capacity, while also offering superior scalability and adaptability to network heterogeneity. Despite its promising advantages, large-scale implementation of NOMA in cellular systems remains elusive due to various challenges, making it a focal point of current research in cellular network technology. While there has been considerable progress in implementing NOMA for broadcast and multicast services, notably with Layer Division Multiplexing (LDM) in next-generation digital TV, the challenges of unicast downlink transmission in NOMA remain largely unexplored. Unicast transmission requires a highly tailored network configuration adaptable to individual user requirements and dynamic channel conditions. Clustering users under a single NOMA channel must be both efficient and adaptive to ensure successful transmission, especially for mobile receiver. Besides, the interplay between NOMA and other 5G technologies remains insufficiently explored, in part due to the lack of an established NOMA-5G framework. Specifically, the collective impact of 5G physical layer technologies such as Low-Density Parity Check (LDPC) coding, Multiple-Input Multiple-Output (MIMO) Beamforming, and mmWave transmission on NOMA鈥檚 performance has not been comprehensively studied. Furthermore, in NOMA schemes involving more than two multiplexed users, known as Multilayer NOMA (N-NOMA), the system becomes increasingly complex and susceptible to noise. While N-NOMA holds considerable promise for scalability, its performance metrics are not yet fully characterized, due to challenges ranging from resource allocation complexities to transceiver design issues. Additionally, existing analytical models for performance evaluation are developed for orthogonal systems, are not fully applicable for assessing NOMA performance. Developing new models that incorporate the impact of non-orthogonality could provide more accurate performance assessments and offer valuable insights for future NOMA research. Initially this thesis investigates the feasibility of LDM for unicast & multicast downlink transmission scenarios for Internet of Things (IoT)- user pairs. The findings indicate the Core Layer (CL) performance aligns with IoT requirements while Enhance Layer (EL) layer is suitable for users. A specialized Bit Error Rate (BER) expression is formulated to precisely predict CL performance, considering Lower Layer (LL) interference with predefined power ratio. Subsequently, the thesis employs a novel surface mobility model and adaptive power ratio allocation to evaluate LDM pair sustainability under various receiver mobility conditions. Extending the LDM-Orthogonal Frequency Division Multiplexing (OFDM) model, this thesis presents a Third Generation Partnership Project (3GPP)-compliant 5G transceiver incorporating N-NOMA. This design incorporates a strategically-arranged set of NOMA functionalities and undergoes a rigorous performance evaluation. In particular, the transceiver provides a comprehensive assessment of N-NOMA performance, considering various transmission parameters such as LDPC code rate, MIMO order, modulation schemes, and channel specifications. These considerations not only provide new insights into non-orthogonal access technologies but also highlight dependencies on these factors for network configuration and optimization. To further advance this work, a one-shot N-NOMA multiplexing technique is developed and implemented, simplifying multi-layer standard sequential combiners to reduce transmission latency and transceiver complexity. A more accurate analytical BER expression is also formulated that considers the impact of both residual and non-residual Successive Interference Cancellation (SIC) errors across NOMA layers. To build upon these advancements, an adaptive Power Allocation (PA) technique is introduced to optimize NOMA cluster sustainability and throughput. Employing a greedy algorithmic approach, this method uses real-time transmission feedback to dynamically allocate power across NOMA layers. In addition, a new Three Dimensional (3D) mobility model has been developed, consistent with existing 3GPP standards, capturing vehicular and pedestrian movement across urban and rural macro & micro-cell environments. When integrated with the PA technique, this model allows for real-time adjustments in the NOMA power ratio, effectively adapting to fluctuating receiver channel conditions. Collectively, the findings from this research not only indicate significant physical layer performance improvements but also provide new insights into the potential of non-orthogonal access technologies. In the LDM-OFDM setup presented in Chapter 3, the EL layer needs 15 dB more Signal-to-Noise Ratio (SNR) than the CL to achieve the same BER, but allows for higher data rates. When it comes to mobility, IoT movement accounts for about 70% of link terminations in scenarios with similar mobility patterns. The N-NOMA-5G shows significant improvement in low SNR performance compared to existing literature. The 3 layer simulations shows on average a 60% reduction in the SNR requirements to achieve similar BER. The implementation of a one-shot multiplexer has demonstrated a substantial reduction in N-NOMA multiplexing time, particularly with the growing number of NOMA layers, as detailed in Chapter 4. Notably, the simulation outcomes spanning 2 to 10 layers of NOMA multiplexing indicate an remarkable 52% reduction in processing time. This underscores the effectiveness of the one-shot multiplexer in enhancing efficiency, particularly as the complexity of the NOMA setup intensifies. The developed analytical model also shows over 95% similarities with the simulation results. The impact of dynamic PA for both static and mobile receivers demonstrates on average, over 40% improvements in link sustainability time for mobile users and for static users, it achieves optimal PA and fast convergence within just 12 iterations, as detailed in Chapter 5

    Potentzia domeinuko NOMA 5G sareetarako eta haratago

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    Tesis ingl茅s 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

    Advanced constellation and demapper schemes for next generation digital terrestrial television broadcasting systems

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    206 p.Esta tesis presenta un nuevo tipo de constelaciones llamadas no uniformes. Estos esquemas presentan una eficacia de hasta 1,8 dB superior a las utilizadas en los 煤ltimos sistemas de comunicaciones de televisi贸n digital terrestre y son extrapolables a cualquier otro sistema de comunicaciones (sat茅lite, m贸vil, cable驴). Adem谩s, este trabajo contribuye al dise帽o de constelaciones con una nueva metodolog铆a que reduce el tiempo de optimizaci贸n de d铆as/horas (metodolog铆as actuales) a horas/minutos con la misma eficiencia. Todas las constelaciones dise帽adas se testean bajo una plataforma creada en esta tesis que simula el est谩ndar de radiodifusi贸n terrestre m谩s avanzado hasta la fecha (ATSC 3.0) bajo condiciones reales de funcionamiento.Por otro lado, para disminuir la latencia de decodificaci贸n de estas constelaciones esta tesis propone dos t茅cnicas de detecci贸n/demapeo. Una es para constelaciones no uniformes de dos dimensiones la cual disminuye hasta en un 99,7% la complejidad del demapeo sin empeorar el funcionamiento del sistema. La segunda t茅cnica de detecci贸n se centra en las constelaciones no uniformes de una dimensi贸n y presenta hasta un 87,5% de reducci贸n de la complejidad del receptor sin p茅rdidas en el rendimiento.Por 煤ltimo, este trabajo expone un completo estado del arte sobre tipos de constelaciones, modelos de sistema, y dise帽o/demapeo de constelaciones. Este estudio es el primero realizado en este campo

    Models and Methods for Network Selection and Balancing in Heterogeneous Scenarios

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    The outbreak of 5G technologies for wireless communications can be considered a response to the need for widespread coverage, in terms of connectivity and bandwidth, to guarantee broadband services, such as streaming or on-demand programs offered by the main television networks or new generation services based on augmented and virtual reality (AR / VR). The purpose of the study conducted for this thesis aims to solve two of the main problems that will occur with the outbreak of 5G, that is, the search for the best possible connectivity, in order to offer users the resources necessary to take advantage of the new generation services, and multicast as required by the eMBMS. The aim of the thesis is the search for innovative algorithms that will allow to obtain the best connectivity to offer users the resources necessary to use the 5G services in a heterogeneous scenario. Study UF that allows you to improve the search for the best candidate network and to achieve a balance that allows you to avoid congestion of the chosen networks. To achieve these two important focuses, I conducted a study on the main mathematical methods that made it possible to select the network based on QoS parameters based on the type of traffic made by users. A further goal was to improve the computational computation performance they present. Furthermore, I carried out a study in order to obtain an innovative algorithm that would allow the management of multicast. The algorithm that has been implemented responds to the needs present in the eMBMS, in realistic scenarios
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