Network Deployment for Maximal Energy Efficiency in Uplink with Zero-Forcing

This work aims to design a cellular network for maximal energy efficiency (EE). In particular, we consider the uplink with multi-antenna base stations and assume that zero- forcing (ZF) combining is used for data detection with imperfect channel state information. Using stochastic geometry and a new lower bound on the average per-user spectral efficiency of the network, we optimize the pilot reuse factor, number of antennas and users per base station. Closed-form expressions are computed from which valuable insights into the interplay between the optimization variables, hardware characteristics, and propagation environment are obtained. Numerical results are used to validate the analysis and make comparisons with a network using maximum ratio (MR) combining. The results show that a Massive MIMO setup arises as the EE-optimal network configuration. In addition, ZF provides higher EE than MR while allowing a smaller pilot reuse factor and a more dense network deployment.Comment: 7 pages, 3 figures; presented at the Global Communications Conference (GLOBECOM'17), 4-8 December, 2017, Singapor

Solving Fractional Polynomial Problems by Polynomial Optimization Theory

This work aims to introduce the framework of polynomial optimization theory to solve fractional polynomial problems (FPPs). Unlike other widely used optimization frameworks, the proposed one applies to a larger class of FPPs, not necessarily defined by concave and convex functions. An iterative algorithm that is provably convergent and enjoys asymptotic optimality properties is proposed. Numerical results are used to validate its accuracy in the non-asymptotic regime when applied to the energy efficiency maximization in multiuser multiple-input multiple-output communication systems.Comment: 5 pages, 2 figures, 1 table, submitted to Signal Processing Letter

Analysis and Implementation of PAPR reduction algorithms for C-OFDM signals

Nowadays multicarrier modulation has become a key technology for communication systems; for example C-OFDM schemes are used in wireless LAN (802.11a/g/n), terrestrial digital television (DVB-T) and audio broadcaster (DAB) in Europe, and discrete multitone (DMT) in x.DSL systems. The principal difficulty with OFDM is the occurrence of the coherent alignment of the time domain parallel signals at the transmitted side which forces system designer to introduce either additional hard computationally device or a suitable power back-off at the high power amplifier in order to cope with the large magnitude signal fluctuation. This leads to a significant increment in computational cost in the former case whereas in a worse allowable power utilization in the latter case with respect to the original system. However since both allowable power and computational cost are subject to a design as well as regulatory limit others solution must be accomplished. Peak reduction techniques reduce maximum-to-mean amplitude fluctuations nominating as a feasible solution. Peak-to-average power ratio is the key metric to measure this amplitude fluctuations at transmitter and to give a clear figure of merit for comparison among different techniques

Máscaras y misterios: lo secreto, lo íntimo

Una lectura psico-pedagógica de la novela La elegancia del erizo. La lectura de esta novela generó en mí continuas analogías con el vínculo pedagógico en el aula, vínculo enmarcado en el reconocimiento, la confianza y la afectividad, habilitantes del aprender

Network Deployment for Maximal Energy Efficiency in Uplink with Multislope Path Loss

This work aims to design the uplink (UL) of a cellular network for maximal energy efficiency (EE). Each base station (BS) is randomly deployed within a given area and is equipped with $M$ antennas to serve $K$ user equipments (UEs). A multislope (distance-dependent) path loss model is considered and linear processing is used, under the assumption that channel state information is acquired by using pilot sequences (reused across the network). Within this setting, a lower bound on the UL spectral efficiency and a realistic circuit power consumption model are used to evaluate the network EE. Numerical results are first used to compute the optimal BS density and pilot reuse factor for a Massive MIMO network with three different detection schemes, namely, maximum ratio combining, zero-forcing (ZF) and multicell minimum mean-squared error. The numerical analysis shows that the EE is a unimodal function of BS density and achieves its maximum for a relatively small density of BS, irrespective of the employed detection scheme. This is in contrast to the single-slope (distance-independent) path loss model, for which the EE is a monotonic non-decreasing function of BS density. Then, we concentrate on ZF and use stochastic geometry to compute a new lower bound on the spectral efficiency, which is then used to optimize, for a given BS density, the pilot reuse factor, number of BS antennas and UEs. Closed- form expressions are computed from which valuable insights into the interplay between optimization variables, hardware characteristics, and propagation environment are obtained.Comment: 30 pages, 5 figures, 2 tables, https://ieeexplore.ieee.org/document/8362685

El aula: una invitación a crear

Concebir el aula como un espacio-tiempo de creación supone un desafío tanto para el enseñante como para el aprendiente. Desafío que interpela ambas subjetividades, las que se encuentran convocadas, signadas para la construcción del saber. Enseñante y aprendiente nacen en el contexto de una relación pedagógico-didáctica cuyo soporte está constituido por un juego de tensiones políticas, estéticas, éticas, epistemológicas y axiológicas las que se enmarcan en cierta concepción del aprender y enseñar y su relación con el sentir-pensar. Relación de sometimiento, control, disciplina, muerte, o, relación de libertad, cuidado, emancipación, vida. Elaborar, entonces, un dispositivo pedagógico-didáctico que despierte la imaginación supone la configuración de un dispositivo abierto, flexible, dando lugar a lo inesperado, organizando las contingencias, ofreciendo el encuentro con múltiples y hasta disparatados materiales procedentes de distintas fuentes; todo lo cual invite el aprender, despierte el deseo de conocer. La actividad propuesta tomará la forma de una “puesta en relación” por medio de la cual los sujetos pondrán en funcionamiento una operación mental -creatividad, divergencia- la que los conducirá a la re-construcción y elaboración subjetiva del saber y su correspondiente apropiación que le permite ir construyendo la autonomía; puesto que toda creación es una diferenciació

Wide-Aperture MIMO via Reflection off a Smooth Surface

This paper provides a deterministic channel model for a scenario where wireless connectivity is established through a reflection off a smooth planar surface of an infinite extent. The developed model is rigorously built upon the physics of wave propagation and is as precise as tight are the unboundedness and smoothness assumptions on the surface. This model allows establishing how line-of-sight multiantenna communication is altered by a reflection off an electrically large surface, a situation of high interest for mmWave and terahertz frequencies.Comment: arXiv admin note: text overlap with arXiv:2205.0121

Aportes desde A. Adler a la educación

El entramado hombre-mundo está cargado de tensiones, los griegos hablaban del agón –pugna, lucha, contienda–. La historia de la humanidad nos muestra cómo los hombres han ido confrontando, resolviendo el cotidiano vivir; y que el mismo es siempre una construcción colectiva. La vida en común es la condición de posibilidad y sostén de lo humano. La vida anímica y su visión del mundo la podemos representar como una multiplicidad de juegos caleidoscópicos. El encuentro del hombre con lo exógeno no es neutro, está siempre enmarcado por sus “apercepciones o percepciones tendenciosas” –Adler–. La realidad si es que existe nunca es una y estática, es siempre relativa, diversa, múltiple, móvil; resultado de una singular producción, creación humana. Fuerte concepción subjetiva de la visión del mundo.Adler afirma que el “estilo de vida” y el respectivo sentido están condicionados por las opiniones que los hombres tienen de sí mismos y del mundo. Desde una concepción holista mira y busca comprender al mundo y la singular forma de ser y estar en é