792 research outputs found
On the genetic optimization of APSK constellations for satellite broadcasting
Both satellite transmissions and DVB applications over satellite present
peculiar characteristics that could be taken into consideration in order to
further exploit the optimality of the transmission. In this paper, starting
from the state-of-the-art, the optimization of the APSK constellation through
asymmetric symbols arrangement is investigated for its use in satellite
communications. In particular, the optimization problem is tackled by means of
Genetic Algorithms that have already been demonstrated to work nicely with
complex non-linear optimization problems like the one presented hereinafter.
This work aims at studying the various parameters involved in the optimization
routine in order to establish those that best fit this case, thus further
enhancing the constellation.Comment: IEEE International Symposium on Broadband Multimedia Systems and
Broadcasting (BMSB), 2014; IEEE proceedings, 201
IEEE Transactions on Broadcasting Special Issue on: 5G for Broadband Multimedia Systems and Broadcasting
[EN] The upcoming fifth-generation ( 5G ) of wireless communications technologies is expected to revolutionize society digital transformation thanks to its unprecedented wireless performance capabilities, providing speeds of several Gbps, very low latencies well below 5 ms, ultra-reliable transmissions with up to 99.999% success probability, while being able to handle a huge number of devices simultaneously connected to the network. The first version of the 3GPP specification (i.e., Release 15) has been recently completed and many 5G trials are under plan or carrying out worldwide, with the first commercial deployments happening in 2019."© 2019 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."Gomez-Barquero, D.; Li, W.; Fuentes, M.; Xiong, J.; Araniti, G.; Akamine, C.; Wang, J. (2019). IEEE Transactions on Broadcasting Special Issue on: 5G for Broadband Multimedia Systems and Broadcasting. IEEE Transactions on Broadcasting. 65(2):351-355. https://doi.org/10.1109/TBC.2019.2914866S35135565
Adopting multiview pixel mapping for enhancing quality of holoscopic 3D scene in parallax barriers based holoscopic 3D displays
The Autostereoscopic multiview 3D Display is robustly developed and widely available in commercial markets. Excellent improvements are made using pixel mapping techniques and achieved an acceptable 3D resolution with balanced pixel aspect ratio in lens array technology. This paper proposes adopting multiview pixel mapping for enhancing quality constructed holoscopic 3D scene in parallax barriers based holoscopic 3D displays achieving great results. The Holoscopic imaging technology mimics the imaging system of insects, such as the fly, utilizing a single camera, equipped with a large number of micro-lenses, to capture a scene, offering rich parallax information and enhanced 3D feeling without the need of wearing specific eyewear. In addition pixel mapping and holoscopic 3D rendering tools are developed including a custom built holoscopic 3D displays to test the proposed method and carry out a like-to-like comparison.This work has been supported by European Commission under Grant FP7-ICT-2009-4 (3DVIVANT). The authors wish to ex-press their gratitude and thanks for the support given throughout the project
Reception performance studies for the evaluation and improvement of the new generation terrestrial television systems
270 p.La industria de la TV ha experimentado grandes cambios en las últimas décadas. Las expectativas cada vez mayores de los espectadores y la reducción del espectro disponible para los servicios de TV han provocado la necesidad de sistemas más robustos de Televisión Digital Terrestre (TDT).El primer intento de cumplir estos requisitos es el estándar europeo DVB-T2 (2009). La publicación de un nuevo estándar significa el inicio de un proceso de evaluación del rendimiento del mismo mediante, por ejemplo, estudios de cobertura u obtención de valores de umbral de relación señal / ruido (SNR). Al inicio de esta tesis, este proceso estaba casi terminado para recepción fija y móvil. Sin embargo, la recepción en interiores no se había estudiado en detalle. Por esta razón, esta tesis completa la evaluación de DVB-T2 en interiores y define una nueva metodología de evaluación optimizada para este escenario.A pesar de que DVB-T2 emplea tecnologías muy avanzadas, el sistema se definió hace casi diez años y desde entonces han aparecido nuevas técnicas avanzadas, como por ejemplo nuevos códigos de corrección de errores o la nueva técnica de multiplexación por división en capas (LDM). Estas nuevas técnicas tampoco han sido evaluadas en entornos de interior, por lo que esta tesis incluye el análisis de las mismas evaluando su idoneidad para mejorar el rendimiento de DVB-T2. Además, se ha comprobado que los algoritmos tradicionales de los receptores TDT no están optimizados para los nuevos escenarios en los que se consideran las señales multicapa y recepción móvil. Por esta razón, se han propuesto nuevos algoritmos para mejorar la recepción en este tipo de situaciones.El último intento de hacer frente a los altos requisitos actuales de TDT es el estándar americano ATSC 3.0 (2016). Al igual que con DVB-T2, se necesita proceso completo de evaluación 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
Device-oriented energy-aware utility-based priority scheduler for video streaming over LTE system
Nowadays people tend to spend most of their time in front of a screen, and expect to be able to connect to the Internet anytime and anywhere and from any type of mobile device. Therefore, fast surfing speed on Internet, high resolution display screen, advanced multi-core processor and lasting battery support are becoming the significant standards in the nowadays mobile devices. In this context the network operators must be able to differentiate between their multiscreen offerings in order to ensure uninterrupted, continuous, and smooth video streaming with minimal delay, jitter, and packet loss. This paper proposes a novel Device-Oriented Energy-Aware Utility-based Priority scheduling (DE-UPS) algorithm which makes use of device differentiation in order to ensure seamless multimedia services over LTE networks. The priority decision is based on the device classification, energy consumption of the mobile device and the multimedia stream tolerance to packet loss ratio
5G Radio Access Network Architecture for Terrestrial Broadcast Services
The 3rd Generation Partnership Project (3GPP) has defined based on the Long
Term Evolution (LTE) enhanced Multicast Broadcast Multimedia Service (eMBMS) a
set of new features to support the distribution of Terrestrial Broadcast
services in Release 14. On the other hand, a new 5th Generation (5G) system
architecture and radio access technology, 5G New Radio (NR), are being
standardised from Release 15 onwards, which so far have only focused on unicast
connectivity. This may change in Release 17 given a new Work Item set to
specify basic Radio Access Network (RAN) functionalities for the provision of
multicast/broadcast communications for NR. This work initially excludes some of
the functionalities originally supported for Terrestrial Broadcast services
under LTE e.g. free to air, receive-only mode, large-area single frequency
networks, etc. This paper proposes an enhanced Next Generation RAN architecture
based on 3GPP Release 15 with a series of architectural and functional
enhancements, to support an efficient, flexible and dynamic selection between
unicast and multicast/broadcast transmission modes and also the delivery of
Terrestrial Broadcast services. The paper elaborates on the Cloud-RAN based
architecture and proposes new concepts such as the RAN Broadcast/Multicast
Areas that allows a more flexible deployment in comparison to eMBMS. High-level
assessment methodologies including complexity analysis and inspection are used
to evaluate the feasibility of the proposed architecture design and compare it
with the 3GPP architectural requirements.Comment: 12 pages, 10 figures, 2 tables, IEEE Trans. Broadcastin
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