128 research outputs found

    MIMO Scattered Pilot Performance and Optimization for ATSC 3.0

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    (c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this[EN] ATSC 3.0 is the latest digital terrestrial television (DTT) standard, and it allows a higher spectral efficiency and/or a transmission robustness with multiple-input multiple-output (MIMO) technology compared to existing DTT standards. Regarding MIMO channel estimation, two pilot encoding algorithms known as Walsh-Hadamard encoding and Null Pilot encoding are possible in ATSC 3.0. The two MIMO pilot algorithms are standardized so as to have the same pilot positions and the same pilot boosting as single-input single-output, and the optimum pilot configuration has not been fully evaluated for MIMO. This paper focuses on the performance evaluation and optimization of the pilot boosting and the pilot patterns for two MIMO pilot encoding algorithms in ATSC 3.0 using physical layer simulations. This paper provides a great benefit to broadcasters to select the MIMO pilot configuration including pilot boosting, pilot pattern, and pilot encoding algorithm that better suits their service requirements. Several channel interpolation algorithms have been taken into account as a typical receiver implementation in both fixed SFN reception and mobile reception.This work was supported in part by the Ministry of Economy and Competitiveness of Spain under Grant TEC2014-56483-R, and in part by the European FEDER Fund.Shitomi, T.; Garro, E.; Murayama, K.; Gomez-Barquero, D. (2018). MIMO Scattered Pilot Performance and Optimization for ATSC 3.0. IEEE Transactions on Broadcasting. 64(2):188-200. https://doi.org/10.1109/TBC.2017.2755262S18820064

    MIMO Sphere Decoding With Successive Interference Cancellation for Two-Dimensional Non-Uniform Constellations

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    [EN] Non-uniform constellations (NUCs) have been introduced to improve the performance of quadrature amplitude modulation constellations. 1D-NUCs keep the squared shape, while 2D-NUCs break that constraint to provide robustness. An impending problem with multiple-input multiple-output (MIMO) is the optimum demapping complexity, which grows exponentially with the number of antennas and the constellation order. Some well-known sub-optimum MIMO demappers, such as soft fixed-complexity sphere decoders (SFSD), can reduce that complexity. However, SFSD demappers do not work with the 2D-NUCs, since they perform a quantization step in separated I/Q components. In this letter, we provide an efficient solution for the 2D-NUCs based on Voronoi regions. Both complexity implications and SNR performance are also analyzed.This work was partially supported by the Ministry of Economy and Competitiveness of Spain (TEC2014-56483-R), co-funded by the European FEDER fund.Barjau, C.; Fuentes, M.; Shitomi, T.; Gomez-Barquero, D. (2017). MIMO Sphere Decoding With Successive Interference Cancellation for Two-Dimensional Non-Uniform Constellations. IEEE Communications Letters. 21(5):1015-1018. doi:10.1109/LCOMM.2017.2653775S1015101821

    Antibacterial and cytotoxic effects of photoexcited Au clusters via blue high-power or white low-power light emitting diode irradiation

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    The development of photosensitizers and light sources has enabled the use of antimicrobial photodynamic therapy (aPDT) in various dental therapies. In the present study, we compared the antibacterial and cytotoxic effects of Au clusters photoexcited by blue and white LED irradiation. We fabricated novel photosensitizers, captopril-protected gold (Capt-Au) clusters and lysozyme-stabilized gold (Lyz-Au) clusters, for aPDT. Au clusters were then photoexcited by two kinds of light sources, blue high-power and white low-power light-emitting diodes (LEDs). Since white LED contains a wide spectrum of light (400–750 nm), white LED would be relevant for aPDT even if using a low-power source. The turbidity and viability of Streptococcus mutans were assessed following application of Capt-Au clusters (500 μg/mL) or Lyz-Au clusters (1,000 μg/mL) photoexcited by a blue high-power LED (1,000 mW/cm2) or white low-power LED (80 mW/cm2). In addition, the cytotoxicity of Au clusters and LED irradiation was evaluated in NIH3T3 and MC3T3-E1 cells. Au clusters photoexcited by the white low-power LED equally decreased the turbidity and viability of S. mutans compared with blue high-power LED. However, Au clusters photoexcited by white LED irradiation caused decreased cytotoxicity in mammalian cells compared with those photoexcited by blue LED irradiation. In conclusion, white LEDs possess biosafe properties for aPDT using Au clusters

    Performance evaluation of MIMO channel estimation for ATSC 3.0

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    [Otros] ATSC 3.0, the latest Digital Terrestrial Television (DTT) standard, allows a higher spectral efficiency and/or a transmission robustness with Multiple-Input Multiple-Output (MIMO) technology compared to existing single-antenna DTT networks. Regarding MIMO channel estimation, two pilot encoding algorithms known as Walsh-Hadamard encoding and Null pilot encoding are possible in ATSC 3.0. The two MIMO pilot algorithms are standardized so as to have the same pilot positions and the same pilot boosting as SISO, but the performance has not been evaluated. This paper focuses on the performance evaluation of the two MIMO pilot encoding algorithms in ATSC 3.0 using physical layer simulations. Results can be used as guidelines or recommended practices to broadcasters to select the MIMO pilot encoding algorithm that better suits their service requirments. Several channel estimation algorithms have been evaluated in both mobile and fixed reception conditions. The simulation results show that Null pilot encoding provides slightly better performance than WalshHadamard encoding for fixed reception but worse performance for mobile reception, especially at high signal-to-noise ratios.This work was partially supported by the Ministerio de Educacion y Ciencia, Spain (TEC2014-56483-R), co-funded by European FEDER funds.Shitomi, T.; Garro, E.; Murayama, K.; Gomez-Barquero, D. (2017). Performance evaluation of MIMO channel estimation for ATSC 3.0. IEEE. 1-5. https://doi.org/10.1109/BMSB.2017.7986237S1

    MMP-13 is constitutively produced in human chondrocytes and co-endocytosed with ADAMTS-5 and TIMP-3 by the endocytic receptor LRP1

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    Matrix metalloproteinase 13 (MMP-13) degrades collagenous extracellular matrix and its aberrant activity associates with diseases such as arthritis, cancer, atherosclerosis and fibrosis. The wide range of MMP-13 proteolytic capacity suggests that it is a powerful, potentially destructive proteinase and thus it has been believed that MMP-13 is not produced in most adult human tissues in the steady state. Present study has revealed that human chondrocytes isolated from healthy adults constitutively express and secrete MMP-13, but that it is rapidly endocytosed and degraded by chondrocytes. Both pro- and activated MMP-13 bind to clusters II and III of low-density lipoprotein (LDL) receptor-related protein 1 (LRP1). Domain deletion studies indicated that the hemopexin domain is responsible for this interaction. Binding competition between MMP-13 and ADAMTS-4, -5 or TIMP-3, which also bind to cluster II, further shown that the MMP-13 binding site within cluster II is different from those of ADAMTS-4, -5 or TIMP-3. MMP-13 is therefore co-endocytosed with ADAMTS-5 and TIMP-3 by human chondrocytes. These findings indicate that MMP-13 may play a role on physiological turnover of cartilage extracellular matrix and that LRP1 is a key modulator of extracellular levels of MMP-13 and its internalization is independent of the levels of ADAMTS-4, -5 and TIMP-3

    Mucinous cystic neoplasms of the mesentery: a case report and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Mucinous cystic neoplasms arise in the ovary and various extra-ovarian sites. While their pathogenesis remains conjectural, their similarities suggest a common pathway of development. There have been rare reports involving the mesentery as a primary tumour site.</p> <p>Case presentation</p> <p>A cystic mass of uncertain origin was demonstrated radiologically in a 22 year old female with chronic abdominal pain. At laparotomy, the mass was fixed within the colonic mesentery. Histology demonstrated a benign mucinous cystadenoma.</p> <p>Methods and results</p> <p>We review the literature on mucinous cystic neoplasms of the mesentery and report on the pathogenesis, biologic behavior, diagnosis and treatment of similar extra-ovarian tumors. We propose an updated classification of mesenteric cysts and cystic tumors.</p> <p>Conclusion</p> <p>Mucinous cystic neoplasms of the mesentery present almost exclusively in women and must be considered in the differential diagnosis of mesenteric tumors. Only full histological examination of a mucinous cystic neoplasm can exclude a borderline or malignant component. An updated classification of mesenteric cysts and cystic tumors is proposed.</p

    Evaluation and Optimization of Multiple-Input Multiple-Output Antenna Schemes for Next-Generation Wireless Broadcasting

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    [ES] Los esquemas de antenas de múltiples entradas y múltiples salidas (MIMO) pueden maximizar la eficiencia espectral de los sistemas de Televisión Digital Terrestre (TDT) para la provisión de contenidos de gran capacidad, como los servicios emergentes de televisión de ultra alta definición (UHDTV), en el cada vez más escaso y limitado espectro radioeléctrico de la TDT debido a la creciente demanda de servicios inalámbricos de banda ancha (4G y 5G). Las tecnologías MIMO han sido desarrolladas inicialmente en la especificación técnica de TDT DVB-NGH (Digital Video Broadcasting Next Generation Handheld) y estandarizadas en el último estándar de TDT, ATSC 3.0 (Advanced Television Systems Committee 3rd Generation). Sin embargo, no hay despliegues comerciales MIMO de TDT. Por otro lado, la industria móvil ha desarrollado una tecnología de radiodifusión móvil, conocida como hoy en día como 5G Broadcast, basado en LTE (Long Term Evolution). Aunque LTE incorpora MIMO para transmisiones unicast punto a punto, 5G Broadcast sólo utiliza una única antenna en transmisión. Esta tesis doctoral tiene como objetivo evaluar el rendimiento de MIMO para radiodifusión (terrestrial broadcast) para sistemas inalámbricos de radiodifusión de nueva generación, tanto TDT como sistemas celulares. Durante la estandarización de los sistemas MIMO TDT, el diseño inicial tiene en cuenta condiciones de recepción perfectas, por ejemplo, demoduladores óptimos, información de estado del canal (CSI) perfecta, estimación perfecta de la potencia del ruido, etc. El objetivo principal de esta tesis doctoral es evaluar y optimizar el rendimiento de las transmisiones de radiodifusión MIMO en escenarios realistas. Esta tesis doctoral propone nuevos modelos de canales de propagación MIMO terrestres basados en medidas de campo que pueden utilizarse para la evaluación del rendimiento del sistema MIMO TDT. Además, también optimiza las diferentes configuraciones de transmisión y recepción MIMO, como la estimación de los canales MIMO en el receptor, y el procesado de señal. El escenario considerado en la tesis son torres de alta potencia con recepción fija, característico de las redes de TDT. Los resultados de esta tesis han contribuido al foro de estandarización ATSC, al sector de radiocomunicaciones de la Unión Internacional de Telecomunicaciones (UIT-R) y al proyecto nacional japonés de investigación sobre el sistema TDT de próxima generación.[CA] Els esquemes d"antenes de múltiples entrades i múltiples sortides (MIMO) poden maximitzar l"eficiència espectral dels sistemes de Televisió Digital Terrestre (TDT) per a la provisió de continguts de gran capacitat, com els serveis emergents de televisió d"ultra alta definició (UHDTV) , en el cada vegada més escàs i limitat espectre radioelèctric de la TDT a causa de la creixent demanda de serveis sense fil de banda ampla (4G i 5G). Les tecnologies MIMO han estat desenvolupades inicialment en l'especificació tècnica de TDT DVB-NGH (Digital Video Broadcasting Next Generation Handheld) i estandarditzades a l'últim estàndard de TDT, ATSC 3.0 (Advanced Television Systems Committee 3rd Generation). No obstant això, no hi ha desplegaments comercials MIMO de TDT. D'altra banda, la indústria mòbil ha desenvolupat una tecnologia de radiodifusió mòbil, coneguda com avui dia com a 5G Broadcast, basat en LTE (Long Term Evolution). Tot i que LTE incorpora MIMO per a transmissions unicast punt a punt, 5G Broadcast només utilitza una única antena en transmissió. Aquesta tesi doctoral té com a objectiu avaluar el rendiment de MIMO per a radiodifusió (terrestrial broadcast) per a sistemes sense fil de radiodifusió de nova generació, tant TDT com sistemes cel·lulars. Durant l'estandardització dels sistemes MIMO TDT, el disseny inicial té en compte condicions de recepció perfectes, per exemple demoduladors òptims, informació d'estat del canal (CSI) perfecta, estimació perfecta de la potència del soroll, etc. L¿objectiu principal d¿aquesta tesi doctoral és avaluar i optimitzar el rendiment de les transmissions de radiodifusió MIMO en escenaris realistes. Aquesta tesi doctoral proposa nous models de canals de propagació MIMO terrestres basats en mesures de camp que es poden utilitzar per a l'avaluació del rendiment del sistema MIMO TDT. A més, també optimitza les diferents configuracions de transmissió i recepció MIMO, com l'estimació dels canals MIMO al receptor, i el processament de senyal. L'escenari considerat a la tesi són torres d'alta potència amb recepció fixa, característic de les xarxes de TDT. Els resultats d"aquesta tesi han contribuït al fòrum d"estandardització ATSC, al sector de radiocomunicacions de la Unió Internacional de Telecomunicacions (UIT-R) i al projecte nacional japonès de recerca sobre el sistema TDT de propera generació.[EN] Multiple-Input Multiple-Output (MIMO) antenna schemes in Digital Terrestrial Television (DTT) systems aim to maximize the spectral efficiency for the provision of large capacity contents in the scarce and limited DTT Radio-Frequency (RF) channel. The delivery of the emerging Ultra-High Definition TV (UHDTV) services as well as the continuous broadcast spectrum shortage due to the rapidly growing demand for wireless broadband services (4G and 5G) are the motivations for this proposal. MIMO technologies have been firstly developed in the DTT technical specification DVB-NGH (Digital Video Broadcasting Next Generation Handheld) and standardized in the latest DTT standard, ATSC3.0 (Advanced Television Systems Committee 3rd Generation). However, MIMO broadcasting has not been commercialized due to the additional investment for both service providers and receivers. On the other hand, mobile industry has developed mobile broadcast technologies known today as 5G Broadcast based on LTE (Long Term Evolution). Although LTE incorporates MIMO for point to point unicast, 5G Broadcast only uses a single antenna in transmission at the moment. The Ph.D. aims at assessing the performance of MIMO for broadcasting (terrestrial broadcast) for next-generation wireless broadcasting systems, including next-generation wireless broadcasting systems, both DTT and cellular system. During the standardization of MIMO DTT systems, the initial design accounts for perfect reception conditions, e.g., optimal demodulators, perfect Channel State Information (CSI), perfect noise power estimation. The main goal of this PhD is to assess and optimize the performance of MIMO wireless broadcast transmissions in realistic scenarios. This PhD proposes new models of terrestrial MIMO propagation channels based on field measurements which can be utilized for the evaluation of MIMO DTT system. Furthermore, it also optimizes the different MIMO transmission and reception configurations, such as broadcast MIMO channel estimation and signal processing. The scenarios considered in the thesis are high-power high-tower transmitter with fixed reception and characteristics of DTT networks. The results of the PhD have contributed to the ATSC standardization forum, International Telecommunication Union Radiocommunication Sector (ITU-R), and the Japanese national research project on next generation DTT system.Shitomi, T. (2023). Evaluation and Optimization of Multiple-Input Multiple-Output Antenna Schemes for Next-Generation Wireless Broadcasting [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/20259
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