Analysis of a Cooperative Strategy for a Large Decentralized Wireless Network

This paper investigates the benefits of cooperation and proposes a relay activation strategy for a large wireless network with multiple transmitters. In this framework, some nodes cooperate with a nearby node that acts as a relay, using the decode-and-forward protocol, and others use direct transmission. The network is modeled as an independently marked Poisson point process and the source nodes may choose their relays from the set of inactive nodes. Although cooperation can potentially lead to significant improvements in the performance of a communication pair, relaying causes additional interference in the network, increasing the average noise that other nodes see. We investigate how source nodes should balance cooperation vs. interference to obtain reliable transmissions, and for this purpose we study and optimize a relay activation strategy with respect to the outage probability. Surprisingly, in the high reliability regime, the optimized strategy consists on the activation of all the relays or none at all, depending on network parameters. We provide a simple closed-form expression that indicates when the relays should be active, and we introduce closed form expressions that quantify the performance gains of this scheme with respect to a network that only uses direct transmission.Comment: Updated version. To appear in IEEE Transactions on Networkin

On Fundamental Trade-offs of Device-to-Device Communications in Large Wireless Networks

This paper studies the gains, in terms of served requests, attainable through out-of-band device-to-device (D2D) video exchanges in large cellular networks. A stochastic framework, in which users are clustered to exchange videos, is introduced, considering several aspects of this problem: the video-caching policy, user matching for exchanges, aspects regarding scheduling and transmissions. A family of \emph{admissible protocols} is introduced: in each protocol the users are clustered by means of a hard-core point process and, within the clusters, video exchanges take place. Two metrics, quantifying the "local" and "global" fraction of video requests served through D2D are defined, and relevant trade-off regions involving these metrics, as well as quality-of-service constraints, are identified. A simple communication strategy is proposed and analyzed, to obtain inner bounds to the trade-off regions, and draw conclusions on the performance attainable through D2D. To this end, an analysis of the time-varying interference that the nodes experience, and tight approximations of its Laplace transform are derived.Comment: 33 pages, 9 figures. Updated version, to appear in IEEE Transactions on Wireless Communication

A BCS microwave imaging algorithm for object detection and shape reconstruction tested with experimental data

An approach based on the Green function and the Born approximation is used for impulsive radio ultra-wideband (UWB) microwave imaging, in which a permittivity map of the illuminated scenario is estimated using the scattered fields measured at several positions. Two algorithms are applied to this model and compared: the first one solves the inversion problem using a linear operator. The second one is based on the Bayesian compressive sensing (BCS) technique, where the sparseness of the contrast function is introduced as extit{a priori} knowledge in order to improve the inverse mapping. In order to compare both methods, measurements in real scenarios are taken using an UWB radar prototype. The results with real measurements illustrate that, for the considered scenarios, the BCS imaging algorithm has a better performance in terms of range and cross-range resolution allowing object detection and shape reconstruction, with a reduced computational burden, and fewer space and frequency measurements, as compared to the linear operator.Fil: Zilberstein, Nicolás. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Maya, Juan Augusto. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Altieri, Andrés Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; Argentin

A Low-Cost Ultra-Wideband Test-Bed

This paper presents the design and implementation of a simple transceiver test-bed for implementing and testing algorithms for impulsive UWB applications. The platform has been developed using low-cost off-the-shelf components. We have conceived a simple modular architecture that was targeted to low power, short-range applications. The test-bed is discussed,commenting on the main design decisions and the benefits of the chosen architecture. Measurements of some blocks of the system are also presented.Fil: Altieri, Andrés Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Gámez, Pablo. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Marchi, Edgardo Jose. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Cervetto, Marcos. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Bouza, Magadalena. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Electronica; ArgentinaFil: Galarza, Cecilia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaXXXV Simpósio Brasileiro de Telecomunicações e Processamento de SinaisSan PedroBrasilSociedade Brasileira de Telecomunicaçõe

La agroecología y el desarrollo rural sostenible en América Latina

Publicado también en: Agroecología y Desarrollo, No 1, marzo 199

Subjective Media Quality Recovery from Noisy Raw Opinion Scores: A Non-Parametric Perspective

Recent parametric approaches to recover subjective media quality from noisy opinion scores involve assumptions that are challenged by numerous complex factors influencing viewer behavior in subjective tests. These approaches commonly involve modeling scoring behavior using parametric distributions, with parameters estimated through methods like maximum likelihood or Bayesian techniques. This paper proposes instead a nonparametric perspective to address the media quality recovery problem, without making any a priori assumption on the subjects' scoring behavior. We propose and motivate an approach to measure the reliability of each single opinion score of a subject. The proposed measure of reliability is then leveraged to formulate an Entropy-based Subjective Quality Recovery (ESQR) algorithm. Simulations and experiments on real datasets show that the proposed ESQR algorithm compares favorably to several state-of-the-art approaches in terms of robustness to noise across various testing conditions. The code to run ESQR and reproduce the results in this paper is made freely available at: http://media.polito.it/ESQR

High Gain Flatness Discrete Low Noise Amplifier for 3 to 5 GHz UWB Operation

This work presents the design of a discrete low-noiseamplifier which operates in the 3-5 GHz band. Considering thatthis amplifier was to be used for the amplification of narrowmodulated pulses, the design efforts were targeted towardsachieving a flat gain and a flat group delay in the band ofinterest, while keeping noise figure under 3 dB. It is shown thatthe resulting design attains a gain of 14dB±0.2dB in the band of interest and noise figure is less than 2.4 dB.Fil: Gámez, Pablo. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Altieri, Andrés Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Galarza, Cecilia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; Argentina2019 Argentine Conference on ElectronicsMar del PlataArgentinaUniversidad de Mar del Plat

UWB target classification using SVM

Ultra-Wideband(UWB) radar signals are characterized for having both high frequency carrier and high bandwidth. This makes the scattered field from the targets when irradiated with UWB pulses highly dependent of the composition and shape of the target. Our goal is toclassify objects by their composition from their scattered responses. In this paper, we propose to use a Support Vector Machine (SVM) to solve the problem for distinct dielectric materials and sphere elements. For a problem considering Mdifferent materials andRradii, we compare performance of three different SVM configurations. The first one considersthe general problem where each class corresponds to adifferent material. In this approach, each class is trained withdata corresponding to all Rradii. On a second approach,we classify by both radii and material. This gives a largerproblem to solve, where the number of classes of the SVM is M×R+ 1. Finally, a third approach considers a cascadeof SVMs where the first layer consists of a SVM for R+ 1classes, each class associated with one radius, while the secondlayer is composed of Rdifferent SVMs, each corresponding to a different radius, that classify between the Mmaterials. Monte Carlo experiments are run to compare performanceamong the different proposed schemes. We analyze the results considering both classification and algorithmic complexity.Fil: Bouza, Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Altieri, Andrés Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaFil: Galarza, Cecilia Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Simulación Computacional para Aplicaciones Tecnológicas; ArgentinaIEEE Biennial Congress of ArgentinaSan Miguel de TucumanArgentinaInstitute of Electrical and Electronics Engineer