Prototyping and measurements for a LiFi system

Proceedings of: Sensor Array and Multichannel Signal Processing Workshop (SAM), 2016 IEEEWe are witnessing a revolution in wireless technology where Light Fidelity (LiFi) emerges as one potential candidate. In this paper we present a LiFi prototype that allows us to verify the feasibility of deploying this technology. The prototype is based on two Spartan 6 FPGAs and uses a Light Emitting Diode (LED) to transport the information through amplitude changes of the light. The receiver uses a low dark current PIN photodiode. We describe the system design, the receiver algorithms and the measurement set-up. We present some measurements where in a Line of Sight (LOS) channel the received pulses are shown to match the transmitted ones.This work has been partly funded by the Company UVAX-Concepts, within Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica 2013-2016 (TSI-100502-2013-024) and ELISA project (TEC2014-59255-C3-3-R). The authors would like to thank this support

Performance of Waterfilling-based Schemes for Interference Cancellation in 4G Networks

The proceeding at: 3rd International Workshop on Cognitive Information Processing (CIP 2012), took place 2012, May 28-30, in Baiona, España. The event Web site at http://cip2012.tsc.uc3m.es/In this work we consider the optimization of the power assigned to the user streams in a coordinated base station downlink environment with Orthogonal Frequency Division Modulation (OFDM). In this scenario the base stations perform distributed cooperative processing with a block diagonalization scheme to remove interference among users. Two schemes based on the waterfilling technique are proposed and compared to the optimal solution, which can be obtained numerically, by using convex optimization. We show that the proposed schemes achieve a performance, in terms of weighted sum rate, very close to the optimal, without the heavy computational complexity required by the numerical solution. These sum rates are compared in a simplified scenario consisting of two-user and two-cell. Other more realistic multicell scenario and some examples of achievable rates are presented too.The research leading to these results has received funding from the Spanish Government under coordinated projects TEC2008-06327-C03-01/02/03 (MULTI-ADAPTIVE) and TEC2011-29006-C03-01/02/03 (GRE3N) and from EU FP7 project INFSO-ICT-247223 ARTIST 4G.Publicad

A robust support vector algorithm for nonparametric spectral analysis

A new approach to the nonparametric spectral estimation on the basis of the support vector method (SVM) framework is presented. A reweighted least squared error formulation avoids the computational limitations of quadratic programming. The application to a synthetic example and to a digital communication problem shows the robustness of the SVM spectral analysis algorithm.Publicad

Adaptive block diagonalization and user scheduling with out of cluster interference

This proceeding at: European Wireless 2014, took place 2014 Mai, 14-16, in Barcelona (España). The event wb site of http://www.ew2014.org/Interference in a cellular network is one of the main impairments that needs to be overcome. Coordination among the Base Stations may enable the use of the interference to improve the transmission rate at the cost of increased computational complexity and more stringent backhaul and feedback requirements. Practical problems of global coordination can be reduced through clustering which, in turn, will introduce Out of Cluster Interference (OCI). OCI can seriously hamper the advantages brought by precoding techniques like Block Diagonalization (BD). In this work we propose a mixed transmission strategy using BD and Single User transmission that is able to overcome the problems introduced by the OCI, in combination with a low complexity scheduling algorithm that enables an increased transmission rate in a multiuser scenario.The research leading to these results has received funding from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía y Competitividad) under projects TEC2011-29006-C03-01(GRE3N-PHY), TEC2011-29006-C03-02 (GRE3N-LINK-MAC), TEC2011-29006-C03-03 (GRE3N-SYST).Publicad

Asymptotic analysis of multiuser-MIMO networks with battery-constrained receivers

The proceeding at: 20th European Wireless 2014, took place 2014, May 14-16, in Barcelona, Spain.In this paper, we present an asymptotic analysis of the behavior of a network where the mobile terminals are considered to be battery-powered devices provided with energy harvesting capabilities. The asymptotic analysis is based on a multiuser MIMO resource allocation strategy where the battery status of the mobile terminals are considered explicitly in the proposed allocation policy. We provide some numerical results and analytic expressions of the expected value of the data rates and the battery levels for different decoding power consumption models when convergence is attained.The research leading to these results has received funding from the European Commission in the framework of the FP7 Network of Excellence in Wireless COMmunications NEWCOM# (Grant agreement no. 318306), from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economia y Competitividad) under projects TEC2011-29006-C03-01 (GRE3N-PHY), TEC2011-29006-C03-02 (GRE3N-LINK-MAC), TEC2011-29006-C03-03 (GRE3N-SYST) and FPI grant BES-2012-052850, and from the Catalan Government under grant 2009 SGR 891.Publicad

Energy profiling of FPGA-based PHY-layer building blocks encountered in modern wireless communication systems

Proceeding at: IEEE 8th Sensor Array and Multichannel Signal Processing Workshop (SAM), took place 2014, Jun, 22-25 in Coruña (españa). The event web site of http://www.gtec.udc.es/sam2014/ .Characterizing the energy cost of different physical (PHY) layer building blocks is becoming increasingly important in modern cellular-based communications, considering the cross sector requirements for performance enhancements and energy savings. This paper presents energy profiling metrics of different PHY-layer FPGA implementations encountered in modern wireless communication systems. The results give an insight of the distribution of the consumed energy in different baseband building blocks or configurations before and after applying power optimizations in the FPGA design and implementation.This work was partially supported by: the Spanish Government under projects TEC2011-29006-C03-01 (GRE3N-PHY), TEC2011-29006-C03-02 (GRE3N-LINKMAC) and TEC2011-29006-C03-03 (GRE3N-SYST); and the European Commission under project NEWCOM# (GA 318306).Publicad

Perfil de fuerza isométrica máxima de los rotadores de la cadera de un equipo senior de fútbol

Hip rotator weakness and imbalances are associated with injuries in athletes. The aim of the present study was to describe the maximal isometric strength (MIS) profile of the internal (HIR) and external (HER) hip rotators in senior soccer players. An observational, descriptive, cross-sectional study was conducted in 21 senior soccer players that voluntarily participated in the present study. The MIS of HIR and HER were measured with the use of a manual Lafayette dynamometer. A Student's t-test for related data (dependent samples) was calculated to determine the existence of differences between the MIS values of the dominant and nondominant hip, and between the MIS values of the HIR and HER. These analyses were complemented with the effect size of all outcomes using Cohen's d statistic. The players showed MIS results of 200.94 ± 29.98 N, 2.66 ± 0.37 N/kg body mass and 1.09 ± 0.16 N*m/kg body mass in the REC; and 154.22 ± 25.09 N, 2.04 ± 0.33 N/kg body mass and 0.84 ± 0.14 N*m/kg body mass in the RIC. Comparison analysis of MIS means in the different units of measurement showed higher values in HER than in HIR (p = 0.000; Cohen's d > 1.631 [large]). In conclusion, a standardized assessment method has obtained normative values of the FIM profile of hip rotators higher than other soccer players of higher competitive level and both sexes. The FIM values of HER are higher than HIR.La debilidad y desequilibrios de los rotadores de cadera están asociados con las lesiones en los deportistas. El objetivo del presente estudio fue describir el perfil de fuerza isométrica máxima (FIM) de los rotadores internos (RIC) y externos (REC) de la cadera en jugadores senior de fútbol. Para ello, se realizó un estudio observacional, descriptivo y de corte transversal con 21 jugadores senior de fútbol que participaron voluntariamente en esta experiencia. La FIM de la RIC y REC se midió con un dinamómetro manual Lafayette. Se realizó una prueba t de Student para determinar la existencia de posibles diferencias entre la FIM de la cadera dominante y no dominante, y entre los valores de la FIM de RIC y REC. Estos análisis se complementaron con el cálculo del tamaño del efecto mediante la d de Cohen. Los jugadores mostraron resultados de FIM de 200,94 ± 29,98 N, 2,66 ± 0,37 N/kg de masa corporal y 1,09 ± 0,16 N*m/kg de masa corporal en la REC; y 154,22 ± 25,09 N, 2,04 ± 0,33 N/kg de masa corporal y 0,84 ± 0,14 N*m/kg de masa corporal en la RIC. El análisis comparativo de la FIM en las diferentes unidades de medida mostró valores superiores en los REC que en los RIC (p = 0,000; d de Cohen > 1,631 [grande]). Tomando como base podemos concluir, que el procedimiento estandarizado de evaluación empleado en este estudio ha obtenido valores normativos del perfil de FIM de los rotadores de la cadera superiores a los descritos para otros jugadores de fútbol de nivel competitivo superior de ambos sexos. Los valores de la FIM de los REC son superiores a los RIC

Perfil de fuerza isométrica máxima de los rotadores de la cadera de un equipo senior de fútbol. Isometric maximum strength profile of hip rotators of a senior soccer team

none4sìResumen La debilidad y desequilibrios de los rotadores de cadera están asociados con las lesiones en los deportistas. El objetivo del presente estudio fue describir el perfil de fuerza isométrica máxima (FIM) de los rotadores internos (RIC) y externos (REC) de la cadera en jugadores senior de fútbol. Para ello, se realizó un estudio observacional, descriptivo y de corte transversal con 21 jugadores senior de fútbol que participaron voluntariamente en esta experiencia. La FIM de la RIC y REC se midió con un dinamómetro manual Lafayette. Se realizó una prueba t de Student para determinar la existencia de posibles diferencias entre la FIM de la cadera dominante y no dominante, y entre los valores de la FIM de RIC y REC. Estos análisis se complementaron con el cálculo del tamaño del efecto mediante la d de Cohen. Los jugadores mostraron resultados de FIM de 200,94 ± 29,98 N, 2,66 ± 0,37 N/kg de masa corporal y 1,09 ± 0,16 N*m/kg de masa corporal en la REC; y 154,22 ± 25,09 N, 2,04 ± 0,33 N/kg de masa corporal y 0,84 ± 0,14 N*m/kg de masa corporal en la RIC. El análisis comparativo de la FIM en las diferentes unidades de medida mostró valores superiores en los REC que en los RIC (p = 0,000; d de Cohen > 1,631[grande]).Tomando como base podemos concluir, que el procedimiento estandarizado de evaluación empleado en este estudio ha obtenido valores normativos del perfil de FIM de los rotadores de la cadera superiores a los descritos para otros jugadores de fútbol de nivel competitivo superior de ambos sexos. Los valores de la FIM de los REC son superiores a los RIC. Abstract Hip rotator weakness and imbalances are associated with injuries in athletes. The aim of the present study was to describe the maximal isometric strength (MIS) profile of the internal (HIR) and external (HER) hip rotators in senior soccer players. An observational, descriptive, cross-sectional study was conducted in 21 senior soccer players that voluntarily participated in the present study. The MIS of HIR and HER were measured with the use of a manual Lafayette dynamometer. A Student’s t-test for related data (dependent samples) was calculated to determine the existence of differences between the MIS values of the dominant and nondominant hip, and between the MIS values of the HIR and HER. These analyses were complemented with the effect size of all outcomes using Cohen’s d statistic. The players showed MIS results of 200.94 ± 29.98 N, 2.66 ± 0.37 N/kg body mass and 1.09 ± 0.16 N*m/kg body mass in the REC; and 154.22 ± 25.09 N, 2.04 ± 0.33 N/kg body mass and 0.84 ± 0.14 N*m/kg body mass in the RIC. Comparison analysis of MIS means in the different units of measurement showed higher values in HER than in HIR (p = 0.000; Cohen’s d > 1.631 [large]). In conclusion, a standardized assessment method has obtained normative values of the FIM profile of hip rotators higher than other soccer players of higher competitive level and both sexes. The FIM values of HER are higher than HIR.openAntonio Cejudo, José Manuel Armada-Zarco, Riccardo Izzo, Pilar Sainz de BarandaCejudo, Antonio; Manuel Armada-Zarco, José; Izzo, Riccardo; Sainz de Baranda, Pila