4,061 research outputs found

    The κ-µ Shadowed Fading Model with Integer Fading Parameters

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    (c) 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. DOI: 10.1109/TVT.2017.2678430We show that the popular and general κ-μ shadowed fading model with integer fading parameters μ and m can be represented as a mixture of squared Nakagami- m̂ (or Gamma) distributions. Thus, its PDF and CDF can be expressed in closed-form in terms of a finite number of elementary functions (powers and exponentials). The main implications arising from such connection are then discussed, which can be summarized as: (1) the performance evaluation of communication systems operating in κ-μ shadowed fading becomes as simple as if a Nakagami- m̂ fading channel was assumed; (2) the κ-μ shadowed distribution can be used to approximate the κ-μ distribution using a closed-form representation in terms of elementary functions, by choosing a sufficiently large value of m; and (3) restricting the parameters μ and m to take integer values has limited impact in practice when fitting the κ-μ shadowed fading model to field measurements. As an application example, the average channel capacity of communication systems operating under κ-μ shadowed fading is obtained in closed-form.Universidad de Málaga. Campus de Excelencia Internacional. Andalucía Tech

    The Fluctuating Two-Ray Fading Model: Statistical Characterization and Performance Analysis

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    (c) 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.We introduce the fluctuating two-ray (FTR) fading model, a new statistical channel model that consists of two fluctuating specular components with random phases plus a diffuse component. The FTR model arises as the natural generalization of the two-wave with diffuse power (TWDP) fading model; this generalization allows its two specular components to exhibit a random amplitude fluctuation. Unlike the TWDP model, all the chief probability functions of the FTR fading model (PDF, CDF, and MGF) are expressed in closed-form, having a functional form similar to other state-of-the-art fading models. We also provide approximate closed-form expressions for the PDF and CDF in terms of a finite number of elementary functions, which allow for a simple evaluation of these statistics to an arbitrary level of precision. We show that the FTR fading model provides a much better fit than Rician fading for recent small-scale fading measurements in 28 GHz outdoor mm-wave channels. Finally, the performance of wireless communication systems over FTR fading is evaluated in terms of the bit error rate and the outage capacity, and the interplay between the FTR fading model parameters and the system performance is discussed. Monte Carlo simulations have been carried out in order to validate the obtained theoretical expressions.Universidad de Málaga. Campus de Excelencia Internacional. Andalucía Tech

    The Fluctuating Two-Ray Fading Model for mmWave Communications

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    We introduce the Fluctuating Two-Ray (FTR) fading model, a new statistical channel model that consists of two fluctuating specular components with random phases plus a diffuse component. The FTR model arises as a natural generalization of the two-wave with diffuse power (TWDP) fading model proposed by Durgin, Rappaport and de Wolf; in this extended model, the two specular components exhibit a random amplitude fluctuation. Unlike in the TWDP model, we show that all the chief probability functions of the FTR fading model (PDF, CDF and MGF) can be expressed in closed-form. We also show that the FTR fading model provides a much better fit than the Rician fading model for recent small-scale fading measurements of the 28 GHz outdoor millimeter-wave channels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    The fluctuating two-ray fading model: exact and approximate statistical characterization

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    El congreso en el que se ha presentado este artículo no genera libro de actas, por lo que el copyright no se ha transferido a IEEE.We introduce the Fluctuating Two-Ray (FTR) fading model, a new statistical channel model that consists of two fluctuating specular components with random phases plus a diffuse component. The PDF and MGF are expressed in closed-form, having a functional form similar to other state-of-the-art fading models. We also provide an approximate closed-form expressions for the PDF, which allow for a simple evaluation of these statistics to an arbitrary level of precision. We show that the FTR fading model provides a much better fit than Rician fading for recent small-scale fading measurements in 28 GHz outdoor millimeter-wave channels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto MINECO-FEDER TEC2013-42711-R, TEC2014-57901-R y TEC2013-44442-P. Junta de Andalucía P2011-TIC-7109 y P2011-TIC-8238

    A MATLAB program for the computation of the confluent hypergeometric function Φ2

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    We here present a sample MATLAB program for the numerical evaluation of the confluent hypergeometric function Φ2. This program is based on the calculation of the inverse Laplace transform using the algorithm suggested by Simon and Alouini in their reference textbook [1]

    On the Calculation of the Incomplete MGF with Applications to Wireless Communications

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    (c) 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. DOI: 10.1109/TCOMM.2016.2626440The incomplete moment generating function (IMGF) has paramount relevance in communication theory, since it appears in a plethora of scenarios when analyzing the performance of communication systems. We here present a general method for calculating the IMGF of any arbitrary fading distribution. Then, we provide exact closed-form expressions for the IMGF of the very general κ-μ shadowed fading model, which includes the popular κ-μ, η-μ, Rician shadowed, and other classical models as particular cases. We illustrate the practical applicability of this result by analyzing several scenarios of interest in wireless communications: 1) physical layer security in the presence of an eavesdropper; 2) outage probability analysis with interference and background noise; 3) channel capacity with side information at the transmitter and the receiver; and 4) average bit-error rate with adaptive modulation, when the fading on the desired link can be modeled by any of the aforementioned distributions.Universidad de Málaga. Campus de Execelencia Internacional. Andalucía Tech

    A Tractable Line-of-Sight Product Channel Model: Application to Wireless Powered Communications

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    We here present a general and tractable fading model for line-of-sight (LOS) scenarios, which is based on the product of two independent and non-identically distributed κ- μ shadowed random variables. Simple closed-form expressions for the probability density function and cumulative distribution function are derived, which are as tractable as the corresponding expressions derived from a product of Nakagami-m random variables. This newly proposed model simplifies the challenging characterization of LOS product channels, as well as combinations of LOS channels with non-LOS ones. Results are used to analyze performance measures of interest in the context of wireless powered communications.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Memoria de la red de coordinación del tercer curso del grado en Ingeniería Multimedia

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    Durante el presente curso se ha constatado el asentamiento del tercer curso del grado en Ingeniería Multimedia, lo que se deriva de los informes de seguimiento de las asignaturas del curso que, en su gran mayoría, no han destacado problema alguno (con alguna excepción de la que se informa). Por otro lado, se ha llevado a cabo una iniciativa para contrastar si las dependencias entre las asignaturas de tercero con respecto a sus precedentes en el plan de estudios responden en realidad a los planteamientos que se hicieron durante el diseño del mismo, intentando descubrir carencias o inconsistencias en los contenidos. De esta manera, se han detectado dependencias que no son tales, dependencias que faltan y temarios de asignaturas básicas en los que, desde el punto de vista de las asignaturas de tercero faltan o sobran contenidos

    Bilayered smectic phase polymorphism in the dipolar Gay-Berne liquid crystal model

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    We present computer simulations of the Gay–Berne model with a strong terminal dipole. We report the existence of different stable antiferroelectric interdigitated bilayered phases in this model with diverse in-plane organization. The occurrence of these phases depends crucially on the value of the molecular elongation . For = 3 we find an interdigitated bilayered smectic-A phase absent when there is no dipole and a bilayered smectic-T or crystal with positional in-plane tetragonal ordering, different from the hexatic observed in the absence of the molecular dipole. For =4, bilayered smectic-A and in-plane hexatic-ordered smectic-B or crystal phases are observe

    Breather trapping and breather transmission in a DNA model with an interface

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    We study the dynamics of moving discrete breathers in an interfaced piecewise DNA molecule. This is a DNA chain in which all the base pairs are identical and there exists an interface such that the base pairs dipole moments at each side are oriented in opposite directions. The Hamiltonian of the Peyrard--Bishop model is augmented with a term that includes the dipole--dipole coupling between base pairs. Numerical simulations show the existence of two dynamical regimes. If the translational kinetic energy of a moving breather launched towards the interface is below a critical value, it is trapped in a region around the interface collecting vibrational energy. For an energy larger than the critical value, the breather is transmitted and continues travelling along the double strand with lower velocity. Reflection phenomena never occur. The same study has been carried out when a single dipole is oriented in opposite direction to the other ones. When moving breathers collide with the single inverted dipole, the same effects appear. These results emphasize the importance of this simple type of local inhomogeneity as it creates a mechanism for the trapping of energy. Finally, the simulations show that, under favorable conditions, several launched moving breathers can be trapped successively at the interface region producing an accumulation of vibrational energy. Moreover, an additional colliding moving breather can produce a saturation of energy and a moving breather with all the accumulated energy is transmitted to the chain.Comment: 15 pages, 11 figure
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