Partial coordination in clustered base station MIMO transmission

This proceeding at: IEEE Wireless Communications and Networking Conference (WCNC, 2013), took place 2013, April, 7-10, in Shaghai (China)We present partial coordination strategies in a clustered cellular environment, evaluating the achievable rate in the downlink transmission. Block Diagonalization is employed for the coordinated users within the cluster to remove interference, while the interference from non-coordinated users remains. The achievable rate is evaluated resorting to an analytical expression conditioned on the position of the users in the cluster. A partial coordination approach is proposed to reduce the coordination complexity and overhead, where users close to the base station are not coordinated. Two approaches are considered, namely the non-coordinated users can be grouped and assigned separated resources from the coordinated ones, or they can be mixed.This work was supported by projects CSD2008-00010 “COMONSENS” and TEC2011-29006-C03-03 “GRE3N”

Achievable rate and fairness in coordinated base station transmission

This work focuses on the fairness in the distribution of the achievable rate per user in a cellular environment where clusters of base stations coordinate their transmissions in the downlink. Block Diagonalization is employed within the cluster to remove interference among users while the interference coming from other clusters remains. The probability distribution of the achievable rate per user shows a perfect match with a Gamma distribution so that a characterization in terms of mean and variance can provide a useful tool for the design of the clusters and the implementation of fairness strategies in a coordinated base station network with Block Diagonalization.This work is partly funded by the projects “GRE3N”: TEC2011-29006- C03-03, and “COMONSENS”: CSD2008-00010.Publicad

Retos para la inclusión digital : propuestas de futuro

Los días 22 a 25 de septiembre de 2004 se celebró en Murcia el III Congreso Nacional de Tecnología, Diversidad y Educación (Tecnoneet 2004), un foro de encuentro y discusión de carácter pluridisciplinar y abierto a profesionales, usuarios y familias que trabajan, investigan o utilizan las nuevas tecnologías en el campo de la discapacidad y las necesidades educativas específicas. Con motivo de dicho evento, los Comités Científico y Organizador elaboraron un documento de conclusiones del que ofrecemos un extracto. Se puede consultar íntegro en http://www.tecnoneet.or

Bitloaded modified enhanced subcarrier index modulation OFDM for visible light communications

Proceeding of: 2nd International Conference on Wireless Communication Systems and Networks (MIC-Wireless 2015), Barcelona, August 7th-9th 2015This paper investigates the use of bit loading al- gorithms in order to use ESIM OFDM in frequency selective channels. This work focuses on maximizing the bit rate minimiz- ing the loss of spectral efficiency because of the insertion of idle subcarriers. Besides, the modified ESIM OFDM is generalized to support groups of subcarriers of arbitrary size based on the number of idle subcarriers. The effect of this generalization, as well as the new bit distribution after using bit loading, on the peak to average power ratio (PAPR) and the bit error rate (BER) are analyzed. Additionally a novel way to evaluate the BER in such a system is proposed. The proposed scheme is shown to outperform the original ESIM OFDM performance in terms of PAPR, at the cost of a small degradation of the BER. This improvement in the PAPR makes the proposed scheme a good candidate for Optical Wireless Communication (OWC) systems, andThis work has been partly funded by project TEC2014-59255-C3-3-R (ELISA

Empresas de inserción = Social insertion companies

En la actualidad la Economía Social ha demostrado ser un sector de gran importancia. En el año 2013 el número de entidades de Economía Social fue de 44.563, siendo de 2.215.175 las personas relacionadas con la Economía Social. Los datos en el mismo año de las empresas de inserción fueron de 205 empresas, con un total de 4.335 trabajadores (de los cuales 2.086 eran trabajadores de inserción). Las empresas de inserción son, por tanto, las grandes desconocidas, y las que más dificultades tienen para su subsistencia. Son las que dentro de la Economía Social presentan los segundos datos más reducidos en número de empresas y también por número de trabajadores empleados en las Empresas de Inserción Los problemas para competir en un mercado normalizado con trabajadores que no siguen los ritmos que se exigen en las empresas actuales, unido a la escasez en las ayudas a las empresas de inserción lastran las posibilidades de crecimiento. En este estudio se pretende una aproximación a estas Empresas; analizando la normativa que las regula, conociendo las particularidades y diferencias con respecto al resto de empresas y diferenciándolas del resto de entidades de la Economía Socia

Block diagonalization techniques for cellular networks: clustering and scheduling

Mención Internacional en el título de doctorLa necesidad de tasas de transmisión más elevadas y una mayor eficiencia en las redes celulares es la principal motivación para considerar el uso de UFR. La coordinación entre BSs se hace necesaria, entonces, para compensar los problemas introducidos por la interferencia. La coordinación global de la red es demasiado compleja y, además, presenta limitaciones intrínsecas, que impiden su utilización en escenarios reales. La utilización de grupos reducidos de BSs es una alternativa para reducir los requisitos impuestos por la coordinación. Como consecuencia de la agrupación, aparece OCI, la cual perjudica seriamente las comunicaciones. Este trabajo se centra en BD, una técnica de precodificación lineal que combina unas buenas prestaciones con una complejidad relativamente baja. Sin embargo, la interferencia empeora notablemente su funcionamiento. En esta tesis se estudia el canal descendente de una red celular conglomerada, donde se usa BD para coordinar las BSs que forman cada grupo. Se analiza la tasa media obtenible como función de múltiples parámetros del escenario. De especial interés es la dependencia con el tamaño de las agrupaciones, de donde se desprende que existe un tamaño óptimo para los grupos de BSs, por encima del cual no se obtienen mejoras significativas. La equidad del sistema se estudia en presencia de OCI, también como función de diversos parámetros del escenario, como puede ser la asignación de potencia. Se propone una estrategia mixta de transmisión, que combina BD con procesado SU, como mecanismo para combatir las dificultades introducidas por la interferencia que no se gestiona. La estrategia consiste en dos fases: • Los usuarios deciden localmente qué estrategia prefieren para la transmisión, y envían esta información a las BSs. • Las BSs utilizan las decisiones recibidas para planificar las transmisiones, de modo que se pueda optimizar el funcionamiento de la red. El resultado de la estrategia propuesta es una mejora de las prestaciones de BD en presencia de OCI, especialmente para los usuarios más desfavorecidos. Esto se traduce en que, adicionalmente, el sistema se vuelve más justo, al mismo tiempo que el rendimiento de la red aumenta.The need for higher data rates and higher efficiency in cellular networks motivates the use of Universal Frequency Reuse (UFR). Coordination among Base Stations (BSs) is required then to alleviate the performance penalty due to the interference. Global coordination is too complex and has inherent limitations that prevents it from being used in real world scenarios. Clusters of a reduced number of BSs can be considered in order to ease off the requirements of coordination. As a result, Other Cluster Interference (OCI) appears, affecting negatively the communications. This work focuses on Block Diagonalization (BD), a linear precoding technique that combines a good theoretical performance with a relatively low complexity. However, the unwanted interference seriously impacts the results obtained using BD. This thesis studies the downlink of a clustered cellular network, where BD is used to coordinate the BS within each cluster. The mean achievable rate is analyzed as a function of several scenario parameters. Of particular interest is the dependence on the cluster size, which yields that there is an optimum cluster size, beyond which no significant gain is obtained. Fairness considerations are analyzed in the presence of OCI, also studied as a function of scenario parameters such as the power allocation. A mixed strategy using BD and Single User (SU) processing is proposed as a means to overcome the impairment of the unhandled interference. The transmission consists of two stages: • Users locally decide which transmission strategy they prefer and send this information to the BSs. • BSs use the decisions of all users to schedule them for transmission so that the performance of the network is optimized. The result of the proposed strategy is an improvement in the performance of BD in the presence of OCI, especially for the users experiencing the worst conditions. This means that the fairness of the system is also increased, along with the overall performance of the network.Programa Oficial de Doctorado en Multimedia y ComunicacionesPresidente: Lajos Hanzo.- Secretario: Raquel Perez Leal.- Vocal: Atilio Manuel da Silva Gameir

Non-dimensional analysis of experimental pressure drop and energy dissipation measurements in Oscillatory Baffled Reactors

An experimental study is performed to characterize the pressure drop and the power consumption in Oscillatory Baffled Reactors, using dimensionless numbers: the oscillatory Fanning friction factor (f osc ) and the Power number (Po), respectively. Two baffle geometries (one-orifice and three orifices) are tested, for different fluids and oscillating amplitudes. The range of oscillatory Reynolds numbers (Reosc ) tested is 10–1000. Data reduction based on the statistical fitting and the FFT of the pressure drop and velocity signals is introduced to assess the maximum pressure drop and the phase lag between both signals. The new set of experimental data proves the limitations of the conventional models available in the open literature. f osc and Po provide consistent dimensionless results for the different working fluids tested and their trends are clearly related to different flow behaviours: laminar or chaotic flow. Correlations for f osc and Po as a function of Reosc and dimensionless amplitude are obtained.The authors gratefully acknowledge the financial support of the project DPI2015-66493-P by Ministerio de Economía y Competitividad (MINECO, Spain) and the European Regional Development Fund (ERDF)

A new marker for rapid sex identification of red deer (Cervus elaphus)

The red deer (Cervus elaphus) is an economically important game species facing some conservation issues. The knowledge of population parameters such as sex ratios is an important basis for management and conservation. We used previously published Y-chromosomal primers under low-stringency amplification conditions and found that they allow quick and accurate sex identification in this species by producing two different amplicons in males and one in females. Both fragments are clearly different in size and easily separated through agarose gel electrophoresis, allowing one-step sex identification in biological samples such as carcasses, embryos recovered from culled females, and possibly hair or excrements (given sufficient DNA quality). This can help studies on intrauterine sex ratio, sex-biased mortality, or the sex ratio of wild or extensive game populations, with useful applications in demographic studies, game management, and conservation

Hybrid quantum-classical optimization for financial index tracking

Tracking a financial index boils down to replicating its trajectory of returns for a well-defined time span by investing in a weighted subset of the securities included in the benchmark. Picking the optimal combination of assets becomes a challenging NP-hard problem even for moderately large indices consisting of dozens or hundreds of assets, thereby requiring heuristic methods to find approximate solutions. Hybrid quantum-classical optimization with variational gate-based quantum circuits arises as a plausible method to improve performance of current schemes. In this work we introduce a heuristic pruning algorithm to find weighted combinations of assets subject to cardinality constraints. We further consider different strategies to respect such constraints and compare the performance of relevant quantum ans\"{a}tze and classical optimizers through numerical simulations.Comment: 24 pages, 12 figure