Examinando por Autor "Navarro Cadavid, Andres"

Mostrando 1 - 20 de 26

A 3D Game Tool for Mobile Networks Planning
(IEEE, 2010-02-10) Madriñán, Patricia
In this work, we show the concept of serious game applied to a 3D game for mobile planning. We combine the use of a traditional planning tool with a 3D game engine, representing propagation models as "avatars". The tool allows to execute an initial planning and also to "play" a game according to "missions" like perform a planning with a coverage objective.
Adaptive planning of 3G/4G systems using Q-analysis or polyhedral dynamics
(IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2004-01-01) Cardona, Narcis
In this paper we present a method for use Q-analysis in the initial planning process and later dynamic adaptation for 3G/4G cellular systems that intends to balance load in order to maximize capacity and reduce lost and dropped calls independently of the type of service. We support our proposal on dynamic simulations made with an own developed tool for dynamic simulations of CDMA systems, and show initial results that partially probe our proposed method.
Análisis de Desempeño de Mecanismo de QoS en Redes Convergentes
(ResearchGate, 2010-08-01) Cuellar Quiñones, Juan Carlos
En este trabajo se presenta el análisis de de resultados de una serie de simulaciones donde se analiza que mecanismo de QoS logra mantener dentro de valores admisibles los parámetros de calidad de servicio que presentan las recomendaciones Y.1540 y Y.1541 para la aplicación de voz, apoyados en un grupo de configuraciones realizadas en el núcleo de una red convergente con infraestructura MPLS.
Análisis y caracterización de frameworks para detección de aplicaciones maliciosas en android
(ResearchGate, 2014-06-01) Londoño, Sebastian
y caracterización de frameworks para detección de aplicaciones maliciosas en Android. XIV Jornada Internacional de Seguridad Informática ACIS 2014 1  Resumen—Android incorpora distintos sistemas de seguridad para solucionar los problemas generados por aplicaciones malware como el modelo de permisos para cada aplicación, su propia plataforma de distribución de aplicaciones móviles "Google Play", entre otras. Pero existen otras alternativas que tienen como función mejorar la protección contra el software malicioso. En este artículo se presenta la información más reciente sobre metodologías, frameworks y sistemas que permiten resolver algunos de los problemas generados por aplicaciones maliciosas (Malware) para dispositivos móviles con sistema operativo Android.
Applicability of Game Engine for Ray Tracing Techniques in a Complex Urban Environment
(IEEE, 2010-09-10) Navarro Cadavid, Andres
This work presents results for a new method of ray tracing in urban environments using game engine and graphic processing unit (GPU). First advantage obtained with this method is the simplicity for 3D modeling from raster digital elevation model (DEM). Second advantage is the ability to precisely obtain ray parameters and the multiple paths interacting between transmitter and receiver in urban environment for high and low base station. A third advantage is the reduction in computing time by using the GPU capacity. In this paper, we show simulation results and compare them with measurements, obtaining a good fit. ©2010 IEEE.
Comparison of heuristic UTD coefficients in an outdoor scenario
(Institute of Electrical and Electronics Engineers Inc., 2013-05-15) Rego, Cassio G.
This paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on 3D ray-tracing techniques for a Digital Video Broadcasting (DVB) service. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points in an outdoor scenario.
Comparison of Uniform Theory of Diffraction Coefficients for Delay Spread and Angle Spread Estimation Using Game Engines in MIMO
(Institute of Electrical and Electronics Engineers Inc., 2015-09-06) Guevara, Dinael
In this paper, we show the results of the comparison between two different sets of heuristic uniform theory of diffraction (UTD) coefficients and its influence on the results for delay spread and angle spread. We compared our simulation results with measurements in an outdoor environment, showing the influence of the UTD coefficients in the accuracy of the results. The proposed coefficients show a better behavior than a classical set of coefficients widely used in literature.
Comunicaciones inalámbricas - 071 – evaluación de curso
(Universidad Icesi, 2011-01-06T18:20:39Z) Universidad Icesi
Se hicieron dos evaluaciones a lo largo del semestre. La primera consistió en una serie de mediciones de señal WiFi en la Universidad y su verificación con la herramienta WPS. Cada estudiante entregó un informe con las mediciones y el análisis estadístico de los resultados, de acuerdo a la predicción de la herramienta.
Delay spread control hiding first hit objects
(2013-01-01) Navarro Cadavid, Andres
This paper proposes a methodology for the prediction and eventual cancellation of the main scatterer effects on broadcast radio channels. We assume the possibility of using absorbing material or paint to reduce the reflectivity of some surfaces and virtually 'hide' the scatterer, so as to control the maximum Delay Spread in terrestrial Digital Video Broadcasting systems. A desirable condition for the DVB-T2 operators is to limit the Delay Spread of radio channel in conditions where it is not possible to change the location or the orientation of the transmitting antenna; moreover, this can be useful to limit the Inter-Symbol Interference (ISI) and to improve the balance between the interleaving time and the channel capacity. In order to prove the applicability of object hiding, we used ray-tracing 3D techniques to identify the objects that can be hidden or camouflaged, and calculating the effect of objects on parameters of the DVB channel, in this case the delay spread. The results of the simulation applying physical hiding of object shown a expected reduction of Delay Spread. © 2013 EurAAP.
Delay spread in mmwave bands for indoor using Game Engines 3D Ray based Tools
(Institute of Electrical and Electronics Engineers Inc., 2016-04-10) Cruz, William
Simulation results of channel parameters using a Game Engine Ray Based Tool in different operating systems with different hardware architectures and using an open source 3D modeling tool for an indoor scenario are presented in this paper. We present simulation results and compare them with a set of measurements for an indoor scenario in the 5.4 GHz band, obtaining good matches between the rays traced by the tool and measurements for delay spread.
DVB Coverage Prediction Using Game Engine Based Ray-Tracing Techniques
(IEEE, 2011-09-05) Gimenez, Jordi J.
This paper presents the results of an evaluation of a propagation model based on ray-tracing techniques using a game engine and Graphics Processing Unit (GPU) in outdoor scenarios, as a gap-filler for a Digital Video Broadcasting Handheld (DVB-H) service. This model involves complete identification of the parameters of wave propagation, multipath components between the transmitter and the receiver as attenuation, time delay of arrival (TDA), full polarimetric transmission matrix, direction of arrival DoA and the direction of departure DoD. In the paper, we present the results of the simulation and compare them with measurements, obtaining a satisfactory fit. © 2011 IEEE.
Dynamic planning of 3G/4G systems using Q-analysis
(2004-05-25) Cardona, Narcis
In this paper we present a method for use Q-analysis in the initial planning process and later dynamic adaptation for 3G/4G cellular systems that intends to balance load in order to maximize capacity and reduce lost and dropped calls independently of the type of service. We support our proposal on dynamic simulations made with an own developed tool for dynamic simulations of CDMA systems, and show initial results that partially probe our proposed method.
Effect of terrain on electromagnetic propagation in urban environments on the Andean region, using the COST231-Walfisch-Ikegami model and GIS planning tools
(IEE, 2003-03-31) Navarro Cadavid, Andres
This paper includes some results from a research project for the development of an electromagnetic propagation algorithm considering the influence of mountain terrain in UHF (300 MHz-3 GHz) band for wireless communications systems (i.e. 800-900 MHz in DAMPS/US-TDMA/IS-136 and GSM standard). The COST231-Walfisch-Ikegami (1988, 1991) model used in this work has been shown, together with Geographic Information System (GIS) and prediction tools for mobile propagation, to facilitate propagation studies, coverage analysis and analysis of main factors for cell planning in mobile systems. The basic concepts used to design the algorithm, the parameters used in measurements and results analysis in order to verify its applicability in cellular coverage prediction are described. Measurements have been done initially in Bucaramanga, a city located in the Andean Mountain system, for IS-136 band system. Coverage predictions have been done using a locally modified version of CellView, a GIS based Planning tool developed by the Universidad Politecnica de Valencia, while for the measurements a portable monitoring unit (i.e. Miniport Receiver EB200-Rohde&Schwarz from 10 kHz-3 GHz) was used.
Game engines ray-tracing models for indoor channel modeling
(IEEE, 2014-07-06) Cardona, Narcis
This paper investigates the use of a full 3D ray-tracing system based on Game Engine for the prediction of channel parameters in indoor using frequencies lower than usual. We explore the modeling of indoor channel for Digital TV frequencies and analyze the behavior of material on such low frequencies and how the frequencies affect the constitutive parameters of materials in the scenario. Because of the environment used for experimentation, the number of rays is very high and the number of interactions is higher than usual. We show results of the ray tracing model compared with measurements of delay spread at 594MHz.
Heuristic UTD coefficients applied for the channel characterization in an andean scenario
(Institute of Electrical and Electronics Engineers Inc., 2015-07-19) Navarro Cadavid, Andres
This paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on 3D ray-tracing techniques in an andean scenario. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points. Finally, we show the path loss prediction for each heuristic UTD coefficients proposed.
Heuristic UTD coefficients for radiowave coverage prediction in a urban scenario
(IEEE, 2015-11-03) Tami, Diego
This paper presents a comparison of three heuristic coefficients for the Uniform Theory of Diffraction (UTD), used to characterize the radiowave scattering in typical urban scenarios. The coefficients were implemented in a propagation model based on ray-tracing techniques based in image theory. In order to evaluate each coefficient we analyze the statistical behavior of the mean and standard deviation of the absolute errors between the estimated values and the measured data of path loss in a large number of receptor points provided in the literature. Finally, we show the path loss prediction for each UTD coefficients proposed.
Indoor Propagation Using a Game Engine Ray-Based Model in Indoor Scenario at 5.4GHz
(Institute of Electrical and Electronics Engineers Inc., 2016-05-15) Gimenez, Jordi Joan
The results of a simulation of signal propagation strength in indoor environment using a game engine ray-based tool and use of an open source 3D modeling tool for scenario building are presented in this paper, showing the flexibility of the XML description language for this kind of scenario. We show simulation results and compare them with an extensive set of measurements for an indoor scenario with multiple materials in the 5.4GHz band, obtaining a good match between the ray-based tool and measurements of received power. We found also that constitutive parameters have an important effect on the simulation results and made some small adjustments to improve results.
Interference detection in centralized cooperative spectrum sensing from sub-Nyquist samples
(IEEE, 2016-12-21) Sosa, Anibal
Wideband spectrum sensing plays a crucial role in a number of applications among which the cognitive radio (CR) is one of the most prominent. In this work we consider a scenario where the wide band of interest is comprised of multiple communication channels occupied by several independent transmissions. Due to the propagation conditions, some of the transmissions can cause potential interference by occupying the same channel at different locations. In order to alleviate the effect of such interference, we employ a network of distributed sensing nodes that sample the wideband signal at sub-Nyquist rate and share the acquired data with the fusion center. We show that using the structure of the correlations between the sub-Nyquist samples obtained at different sensors, we can detect the presence of potential in-channel interference. We present a concrete approach for estimation of the central frequencies of the channels in which it occurs and demonstrate its effectiveness in simulations.
Measurement-based ray-tracing models calibration in urban environments
(IEEE, 2012-07-08) Cardona, Narcis
This paper investigates the effect produced on the accuracy of the estimate of path loss in an outdoor environment in order to adjust the permittivity values for building wall, building roof and street floor by using a full 3D ray-tracing system. Due to the complexity of a real situation, estimation of path loss using the ray-tracing method is generally assumed one or three large classes of homogeneous materials to represent the building walls, building roofs and street floors in order have a viable model of the 3D environment. However, in a real case, an outdoor environment consists of many buildings and streets made of heterogeneous materials. We analyze the behavior of the statistical variation of standard deviation, correlation coefficient and the average error between the values of estimated and measured path loss data when considering various values of permittivity of these three classes.
A new method for spectrum monitoring networks design
(IEEE, 2013-07-07) Restrepo, Joaquin
In the ITU Spectrum Monitoring handbook, edition 2011, a model for design of radio monitoring systems is suggested. This model is based on the work of Pavliuk et al. In this paper we propose a modified version on the Pavliuk model, using methods from the mobile networks world, like semi-deterministic propagation models and population information. We apply the method for the design of the monitoring network in Costa Rica. © 2013 IEEE.