Analysis and Design of Algorithms for the Improvement of Non-coherent Massive MIMO based on DMPSK for beyond 5G systems

Mención Internacional en el título de doctorNowadays, it is nearly impossible to think of a service that does not rely on wireless communications. By the end of 2022, mobile internet represented a 60% of the total global online traffic. There is an increasing trend both in the number of subscribers and in the traffic handled by each subscriber. Larger data rates, smaller extreme-to-extreme (E2E) delays and greater number of devices are current interests for the development of mobile communications. Furthermore, it is foreseen that these demands should also be fulfilled in scenarios with stringent conditions, such as very fast varying wireless communications channels (either in time or frequency) or scenarios with power constraints, mainly found when the equipment is battery powered. Since most of the wireless communications techniques and standards rely on the fact that the wireless channel is somehow characterized or estimated to be pre or post-compensated in transmission (TX) or reception (RX), there is a clear problem when the channels vary rapidly or the available power is constrained. To estimate the wireless channel and obtain the so-called channel state information (CSI), some of the available resources (either in time, frequency or any other dimension), are utilized by including known signals in the TX and RX typically known as pilots, thus avoiding their use for data transmission. If the channels vary rapidly, they must be estimated many times, which results in a very low data efficiency of the communications link. Also, in case the power is limited or the wireless link distance is large, the resulting signal-tointerference- plus-noise ratio (SINR) will be low, which is a parameter that is directly related to the quality of the channel estimation and the performance of the data reception. This problem is aggravated in massive multiple-input multiple-output (massive MIMO), which is a promising technique for future wireless communications since it can increase the data rates, increase the reliability and cope with a larger number of simultaneous devices. In massive MIMO, the base station (BS) is typically equipped with a large number of antennas that are coordinated. In these scenarios, the channels must be estimated for each antenna (or at least for each user), and thus, the aforementioned problem of channel estimation aggravates. In this context, algorithms and techniques for massive MIMO without CSI are of interest. This thesis main topic is non-coherent massive multiple-input multiple-output (NC-mMIMO) which relies on the use of differential M-ary phase shift keying (DMPSK) and the spatial diversity of the antenna arrays to be able to detect the useful transmitted data without CSI knowledge. On the one hand, hybrid schemes that combine the coherent and non-coherent schemes allowing to get the best of both worlds are proposed. These schemes are based on distributing the resources between non-coherent (NC) and coherent data, utilizing the NC data to estimate the channel without using pilots and use the estimated channel for the coherent data. On the other hand, new constellations and user allocation strategies for the multi-user scenario of NC-mMIMO are proposed. The new constellations are better than the ones in the literature and obtained using artificial intelligence techniques, more concretely evolutionary computation.This work has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie ETN TeamUp5G, grant agreement No. 813391. The PhD student was the Early Stage Researcher (ESR) number 2 of the project. This work has also received funding from the Spanish National Project IRENE-EARTH (PID2020-115323RB-C33) (MINECO/AEI/FEDER, UE), which funded the work of some coauthors.Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan CarlosPresidente: Luis Castedo Ribas.- Secretario: Matilde Pilar Sánchez Fernández.- Vocal: Eva Lagunas Targaron

Control of phase in radial line slot antenna for 5G communications at 60GHz

This paper shows the design of a radial line slot antenna for being used in indoor environments in the 60 GHz band of the future 5G communication systems. The antenna is designed to work in near field situation, creating a uniform field in a certain volume, improving the size of this volume with respect the use of uniform phase. The paper analyzes different configurations of phase on the slots and performs the design of the slot position and length on the upper plate of the radial line slot antenna

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Nanocrystalline calcium phosphate apatites constitute the main inorganic part of hard tissues, and a growing focus is devoted to prepare synthetic analogs, so-called “biomimetic”, able to precisely mimic the morphological and physico-chemical features of biological apatite compounds. Both from fundamental and applied viewpoints, an accurate characterization of nanocrystalline apatites, including their peculiar surface features, and a deep knowledge of crystallization aspects are prerequisites to attempt understanding mineralization phenomena in vivo as well as for designing innovative bioactive materials that may then find applications in bone tissue engineering, either as self-supported scaffolds and fillers or in the form of coatings, but also in other domains such as drug delivery or else medical imaging. Also,interfacial phenomena are of prime importance for getting a better insight of biomineralization and for following the behavior of biomaterials in or close to their final conditions of use. In this view,both adsorption and ion exchange represent essential processes involving the surface of apatite nanocrystals, possibly doped with foreign elements or functionalized with organic molecules of interest. In this review paper, we will address these various points in details based on a large literature survey. We will also underline the fundamental physico-chemical and behavioral differences that exist between nanocrystalline apatites (whether of biological origin or their synthetic biomimetic analogs) and stoichiometric hydroxyapatite

Reaction time on fencing and karate high level athletes

The great speed of the actions in combat sports makes very difficult to react quickJy without mistakes. If the fighter had longer time to react, their reaction would be more accurate. This fact gives relevance to choice lime reaction (CRT) studies on these kinds of sports. The importance of the athletes1 physical or psychological abilities varies depending on the sporl played. According to the requirements of the speciality, players who reach Ihe maximum level will be those who have the characteristics requested to compete on it. These abilities could be innate or "life-long" acquired by training. Previous studies have not confirmed yet in which sports reaction time is more important, in addition, previous measurements should be considered with caution because some of Ihem included movement time in the reaction time results (Martmez de Quel, 2003). An approach to gel further knowledge about this subject, it is comparing the results of e\perts in two or more disciplines with unspecific tests, in which previous sport experience is not required in order to perform the lest

Channel estimation and prediction in a pilot-less massive MIMO TDD using non-coherent DMPSK

A novel time division duplex massive MIMO technique is proposed based on performing a pilot-less channel estimation in the uplink (UL) utilizing reconstructed differentially encoded data. Spatial multiplexing and differentially encoded data is applied both in the UL and in the downlink (DL). In this system, a reference signal is the first one of the differentially encoded streams in the UL and DL, and the pilots for data estimation are avoided while maintaining spatial multiplexing capabilities. To improve the channel estimation we propose to use a linear Wiener filter and we also propose different symbols placing strategies in an OFDM grid. We also propose a detection improvement of the UL data utilizing the predicted channels. We perform an analysis of the MSE of the blind channel estimation using the differentially encoded data and analyze the symbol-error-rate for both the UL and the DL when channel aging is considered. The analysis is corroborated via numerical results and the proposed scheme is shown to outperform its pilot-based counterpart.This work was supported in part by the European Union Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie European Training Network (ETN) TeamUp5G under Grant 813391, and in part by the Spanish National Project IRENE-EARTH (MINECO/AEI/FEDER/UE) under Grant PID2020-115323RB-C33

Behavioural complementarity among frugivorous birds and lizards can promote plant diversity in island ecosystems

The behavioural complementarity of fruit-eating animals is thought to exert a key role in plant community assembly. However, a mechanistic understanding of the causal links between the two processes is still lacking. This study assesses whether complementarity between dispersers in feeding and microhabitat-use behaviour enhances community-scale dispersal services, resulting in a more diverse community of seedlings. We used a Bayesian approach to connect a comprehensive database of seed dispersal effectiveness at a community scale with a transition probability model that accounts for behavioural complementarity. Our model system was the thermosclerophyllous shrubland of the Canary Islands. There, fleshy-fruited plants rely on two types of frugivores: lizards and birds. Lizards consumed all plant species and preferentially used open areas, whereas birds foraged for small single-seeded fruits and dispersed their seeds beneath plants. Through feeding on different sets of plants, they generated a rich seed-rain community. By diversifying the microhabitat of deposition, more species could find suitable recruitment sites. Distinct foraging and microhabitat-use choices led to complementary dispersal services. Lizards ensured that all plant species were present in the seedling community, while birds promoted a more even distribution of them. As a result, diversity in the community of seedlings was enhanced. Overall, our work underscores that behavioural complementarity promotes diversity in the early-regenerating plant communities. These enhanced dispersal services rely on the presence of all functional groups. Thus, in communities where frugivores display unique behaviours, preserving a diverse community of dispersers should be a conservation target. A free Plain Language Summary can be found within the Supporting Information of this article.Fil: Morán López, Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: González Castro, Aarón. Island Ecology and Evolution Research Group ; Argentina. Consejo Superior de Investigaciones Científicas; EspañaFil: Morales, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Nogales, Manuel. Island Ecology and Evolution Research Group ; Argentina. Consejo Superior de Investigaciones Científicas; Españ

Fractionation and fluxes of metals and radionuclides during the recycling process of phosphogypsum wastes applied to mineral CO2 sequestration

The industry of phosphoric acid produces a calcium-rich by-product known as phosphogypsum, which is usually stored in large stacks of millions of tons. Up to now, no commercial application has been widely implemented for its reuse because of the significant presence of potentially toxic contaminants. This work confirmed that up to 96% of the calcium of phosphogypsum could be recycled for CO2 mineral sequestration by a simple two-step process: alkaline dissolution and aqueous carbonation, under ambient pressure and temperature. This CO2 sequestration process based on recycling phosphogypsum wastes would help to mitigate greenhouse gasses emissions. Yet this work goes beyond the validation of the sequestration procedure; it tracks the contaminants, such as trace metals or radionuclides, during the recycling process in the phosphogypsum. Thus, most of the contaminants were transferred from raw phosphogypsum to portlandite, obtained by dissolution of the phosphogypsum in soda, and from portlandite to calcite during aqueous carbonation. These findings provide valuable information for managing phosphogypsum wastes and designing potential technological applications of the by-products of this environmentally-friendly proposal.Junta de Andalucía P10-RNM-6300, P12- RNM-226

Multivariate exploratory data analysis: bias assessment

El objetivo de la presente investigación fue evaluar si el sesgo cometido por los sujetos en una tarea de clasificación de estímulos varió en función del formato de presentación (soles o estrellas) y la forma de asignar las variables (aleatoria, ordenadas según su correlación en 360 grados o representadas en el espacio mediante un biplot: soles o estrellas factoriales). Se encontró que hubo una interacción significativa entre el formato de presentación y la forma de asignar las variables. En concreto, se obtuvo que los sujetos cometieron menos errores cuando clasificaron los soles factoriales que las estrellas factoriales. Asimismo, también clasificaron mejor los soles ordenados que las estrellas ordenadas. Tampoco hubo diferencias significativas entre soles y estrellas cuando no se incluyó ningún tipo de información acerca de las correlaciones (asignación aleatoria), ni entre los soles factoriales y los soles ordenados. Por último, también se obtuvo que los sujetos tardaron más tiempo en completar la tarea en la condición de asignación aleatoria que en la representación factorial.The objective of this investigation was to evaluate if the bias of the subjects varied during a stimulus classification task in relation to the presentation form at (suns and stars) and to the way the variables were assigned (randomly, ordered according to their correlation in 360º or using a biplot: factorial suns or stars). It was found that there was a significant interaction between the presentation format and the method of assigning variables. In particular, it was found that the subjects made fewer mistakes classifying the factorial suns than the factorial stars. Likewise , they also classified better the ordered suns than the ordered stars. There were no significant differences between the suns and stars when no information regarding the correlation was included (random order) nor between the ordered suns and factorial suns. Lastly, it was also found that the subjects took longer to complete a task with random assignment than one with the factorial representation.Ministerio de Educación y Ciencia PB93117

Visual inspection and type of graphs used

El objetivo de la investigación fue estudiar si la evaluación de la efectividad de un tratamiento mediante inspección visual dependía del tipo de representación gráfica. Se estudiaron 3 sujetos a los que se les presentó 3.000 gráficos (1.000 de líneas, 1.000 de barras y 1.000 de caja), representando cada uno de ellos los resultados de un diseño A-B. Los resultados indicaron que los sujetos cometieron mayor número de errores cuando los datos se presentaban mediante líneas o barras.The objective of this research was to see if the evaluation of the effectiveness of a given treatment through visual inspection depends on the type of graphs used. Three subjects were studied with 3000 graphs (1.000 line, 1.000 bar and 1.000 box-plots), each one representing the results of an A-B design. The results indicate that the subjects committed more errors when the data was presented by lines or bars instead of box-plots.Ministerio de Educación y Ciencia PB93-117

Migration Patterns in Male Great Bustards (Otis tarda)

5 paginas, 1 figura y 1 tableThe Great Bustard (Otis tarda) is distributed from Iberia and Morocco in the west to China in the east and has been considered sedentary in all but the northern and eastern parts of its range (Gewalt 1959, Glutz et al. 1973, Cramp and Simmons 1980). However, some studies have reported seasonal changes in population numbers in different areas in the Iberian Peninsula (Hidalgo and Carranza 1990, Alonso et al. 1995), suggesting that the species is a partial migrant (sensu Terrill and Able 1988) in this region. We describe seasonal movements of marked adult male Great Bustards and discuss observed patterns in relation to the following questions: (1) Do migratory males display interannual fidelity to breeding and postbreeding areas? (2) Do males travel significantly farther than females in their seasonal movements? We also suggest several hypotheses that could explain patterns of partial and differential migration in male Great Bustards.This study is a contribution to DGICYT-project PB94–0068.Peer reviewe