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      • SCISCIESCOPUS

        Cloud Transmission: System Performance and Application Scenarios

        Montalban, Jon,Liang Zhang,Gil, Unai,Yiyan Wu,Angulo, Itziar,Salehian, Khalil,Sung-Ik Park,Bo Rong,Wei Li,Heung Mook Kim,Angueira, Pablo,Velez, Manuel [Institute of Electrical and Electronics Engineers 2014 IEEE transactions on broadcasting Vol.60 No.2

        <P>Cloud transmission (Cloud Txn) is a flexible multilayer system that uses spectrum overlay technology to simultaneously deliver multiple program streams with different characteristics and robustness for different services (mobile TV, HDTV, and UHDTV) in one radio frequency channel. Cloud Txn is a multilayer transmission system like layered-division multiplexing. The transmitted signal is formed by superimposing a number of independent signals at desired power levels to form a multilayered signal. The signals of different layers can have different coding, bit rate, and robustness. The upper layer system parameters are chosen to provide very robust transmission that can be used for high-speed mobile broadcasting. The bit rate is traded for powerful coding and robustness so that the signal-to-noise ratio (SNR) threshold at the receiver is in the range of -2 to -3 dB. The top layer is designed to withstand combined noise, co-channel interference and multipath distortion power levels higher than the desired signal power. The lower-layer signal can be a DVB-T2 signal or another new system to deliver HDTV/UHDTV to fixed receivers. The system concept is open to technological advances that might come in the future: BICM/non uniform-QAM, rotated constellations, time frequency slicing or MIMO techniques can be implemented in the Cloud Txn lower (high data rate) layer. The system can have backward compatible future extensions, adding more lower layers for additional services without impact legacy services. This paper describes the performance of Cloud Txn broadcasting system.</P>

      • SCISCIESCOPUS

        Performance Study of Layered Division Multiplexing Based on SDR Platform

        Montalban, Jon,Angulo, Itziar,Regueiro, Cristina,Yiyan Wu,Zhang, Liang,Sung-Ik Park,Jae-Young Lee,Heung Mook Kim,Velez, Manuel,Angueira, Pablo [Institute of Electrical and Electronics Engineers 2015 IEEE transactions on broadcasting Vol.61 No.3

        <P>Two of the main drawbacks of the current broadcasting services are, on the one hand, the lack of flexibility to adapt to the new generation systems requirements, and on the other hand, the incapability of taking a piece of the current mobile services market. In this paper, layered division multiplexing (LDM), which grew out of the concept of Cloud Txn, is presented as a very promising technique for answering those challenges and enhancing the capacity of broadcasting systems. The major contribution of this paper is to present the first comprehensive study of the LDM performance behavior. In particular, in this paper, the theoretical considerations of the LDM implementation are completed with the first computer based simulations and laboratory tests, covering a wide range of stationary channels and the mobile TU-6 channel. The results will support LDM as a strong candidate for multiplexing different services in the next generation broadcasting systems, increasing both flexibility and performance.</P>

      • SCOPUSKCI등재

        A combined pathway of somatic embryogenesis and organogenesis to regenerate radiata pine plants

        Montalban, I.A.,De Diego, N.,Igartua, E. Aguirre,Setien, A.,Moncalean, P. The Korean Society of Plant Biotechnology 2011 Plant biotechnology reports Vol.5 No.2

        This study describes for the first time in Pinus genus a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis from immature seeds of radiata pine. Somatic embryos were obtained from embryogenic line 2162 of Pinus radiata D. Don on EDM basal medium containing $60{\mu}M$ ABA and 6% sucrose. The explants used for organogenesis experiments were either freshly collected somatic embryos or somatic embryos germinated for 1 week. Germination medium was half-strength LP medium, supplemented with 0.2% activated charcoal. Different induction periods and BA concentrations were assayed for shoot induction. After induction treatments, explants were elongated on the same medium used for germination stage. Rooting medium was quarter-strength LP medium supplemented with three different auxin treatments: $1.5mg\;L^{-1}$ 1-naphthalene acetic acid (NAA), $1.5mg\;L^{-1}$ indole-3-butyric acid (IBA) and $1mg\;L^{-1}$ IBA with $0.5mg\;L^{-1}$ NAA (MIX). The effect of the photon flux ($120mmol\;m^{-2}\;s^{-1}$ and darkness) in the first week of the explants in the rooting media was also tested. This methodology could offer an alternative to overcome some problems associated with somatic embryogenesis such as the seasonality of embryogenic tissue (ET) initiation or a low embryo production from the ET, a particularly important issue in the case of genetically transformed ETs.

      • SCIESCOPUS

        Experimental modal analysis of transverse-cracked rails-influence of the cracks on the real track behavior

        Domingo, Laura Montalban,Giner, Beatriz Baydal,Martin, Clara Zamorano,Herraiz, Julia I. Real Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.52 No.5

        Rails are key elements in railway superstructure since these elements receive directly the train load transmitted by the wheels. Simultaneously, rails must provide effective stress transference to the rest of the track elements. This track element often deteriorates as a consequence of the vehicle passing or manufacturing imperfections that cause in rail several defects. Among these rail defects, transverse cracks highlights and are considered a severe pathology because they can suddenly trigger the rail failure. This study is focused on UIC-60 rails with transverse cracks. A 3-D FEM model is developed in ANSYS for the flawless rail in which conditions simulating the crack presence are implemented. To account for the inertia loss of the rail as a consequence of the cracking, a reduction of the bending stiffness of the rail is considered. The numerical models have been calibrated using the first four bending vibration modes in terms of frequencies. These vibration frequencies have been obtained using the Experimental Modal Analysis technique, studying the changes in the modal parameters of the rails induced by the crack and comparing the results obtained by the model with experimental results. Finally, the calibrated and validated models for the single rail have been implemented in a complete railway ballasted track FEM model in order to study the static influence of the cracks on the rail deflection caused by a load passing.

      • SCISCIESCOPUS

        Layered-Division-Multiplexing for High Spectrum Efficiency and Service Flexibility in Next Generation ATSC 3.0 Broadcast System

        Zhang, Liang,Wu, Yiyan,Li, Wei,Rong, Bo,Salehian, Khalil,Lafleche, Sebastien,Wang, Xianbin,Park, Sung Ik,Kim, Heung Mook,Lee, Jae-young,Hur, Namho,Angueira, Pablo,Montalban, Jon Institute of Electrical and Electronics Engineers 2019 IEEE wireless communications Vol.26 No.2

        <P>LDM, a non-orthogonal multiplexing technology, is one of the main innovations in ATSC 3.0, a next generation terrestrial TV broadcast system. This article gives a general overview of the LDM technology, its current applications in the ATSC 3.0 system, and its cost in terms of the required additional complexity. The transmission capacity benefit offered by LDM is explained by theoretical analysis and demonstrated by simulation results. An efficient implementation scheme is described with less than 15 percent complexity increase. New service coverage paradigms enabled by LDM are presented. Finally, more future innovative applications of LDM, along with their benefits and challenges, are introduced. These include using LDM for wireless in-band backhaul, combining LDM with scalable video coding, and the application of LDM in other future broadcasting and 4G/5G broadband systems.</P>

      • SCISCIESCOPUS

        Layered-Division Multiplexing: An Enabling Technology for Multicast/Broadcast Service Delivery in 5G

        Zhang, Liang,Wu, Yiyan,Li, Wei,Salehian, Khalil,Lafleche, Sebastien,Wang, Xianbin,Park, Sung Ik,Kim, Heung Mook,Lee, Jae-young,Hur, Namho,Angueira, Pablo,Montalban, Jon Institute of Electrical and Electronics Engineers 2018 IEEE communications magazine Vol.56 No.3

        <P>Future 5G systems will include a point-to-multipoint (P2MP) transmission mode to achieve high capacity and high spectrum efficiency for multiple use cases, such as IoT, lifeline communications, and broadcast-type services. Layered-division-multiplexing (LDM) is a novel non-orthogonal multiplexing technology recently adopted by the next generation digital TV broadcast system, ATSC 3.0, which is capable of providing significant capacity improvement when delivering multiple broadcast services simultaneously. This article explores the application of LDM as an enabling technology for 5G to achieve high-efficiency P2MP transmission and to deliver more diversified broadcast-type services using the mobile broadband infrastructure. The potential advantages that can be offered by LDM are demonstrated by capacity analysis and computer simulations. Coverage studies show that a 5G P2MP subsystem with LDM can deliver high-quality broadcast services using the broadband infrastructure. Finally, some general guidelines on the receiver implementation are presented to minimize the hardware complexity of consumer devices.</P>

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