On the connection between noncircularly-symmetric and noncentral fading models: univariate and multivariate analysis

This thesis provides new statistical connections between noncircularly-symmetric central and circularly-symmetric noncentral underlying complex Gaussian models. This is particularly interesting since it facilitates the analysis of noncircularly-symmetric models, which are often underused despite their practical interest, since their analysis is more challenging. Although these statistical connections have a wide range of applications in different areas of univariate and multivariate analysis, this thesis is framed in the context of wireless communications, to jointly analyze noncentral and noncircularly-symmetric fading models. We provide an unified framework for the five classical univariate fading models, i.e. the one-sided Gaussian, Rayleigh, Nakagami-m, Nakagami-q and Rician, and their most popular generalizations, i.e the Rician shadowed, η-µ, κ-µ and κ-µ shadowed. Moreover, we present new simple results regarding the ergodic capacity of single-input single-output systems subject to κ-µ shadowed, κ-µ and η-µ fadings. With applications to multiple-input multiple-output communications, we are interested in matrices of the form W=XX^H (or W=X^HX), where X is a complex Gaussian matrix with unequal variance in the real and imaginary parts of its entries, i.e., X belongs to the noncircularly-symmetric Gaussian subclass. By establishing a novel connection with the well-known complex Wishart ensemble, we facilitate the statistical analysis of W and give new insights on the effects of such asymmetric variance profile

On Some Unifications Arising from the MIMO Rician Shadowed Model

This paper shows that the proposed Rician shadowed model for multi-antenna communications allows for the unification of a wide set of models, both for multiple-input multiple-output (MIMO) and single- input single-output (SISO) communications. The MIMO Rayleigh and MIMO Rician can be deduced from the MIMO Rician shadowed, and so their SISO counterparts. Other more general SISO models, besides the Rician shadowed, are included in the model, such as the κ-μ, and its recent generalization, the κ-μ shadowed model. Moreover, the SISO η-μ and Nakagami-q models are also included in the MIMO Rician shadowed model. The literature already presents the probability density function (pdf) of the Rician shadowed Gram channel matrix in terms of the well-known gamma- Wishart distribution. We here derive its moment generating function in a tractable form. Closed- form expressions for the cumulative distribution function and the pdf of the maximum eigenvalue are also carried out.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Caracterización y Simulación de un Diodo Schottky de Microondas

Presentado en el XXVIII Simposium Nacional de la Unión Científica Internacional de Radio. URSI 2013, Santiago de Compostela, 11 al 13 de septiembre de 2013.Microwave diode models included in commercial simulators use a large set of parameters, so they are often difficult to set up in order to match the actual response of a specific device. In this paper a simple model for a zero-bias microwave Schottky diode is presented. Noise characteristics are determined by measurements and then incorporated to the large signal model offered by the manufacturer in the diode datasheet. Using this model a diode power detector in large signal operation is simulated with commercial software, achieving excellent agreement with the measurement results, both in terms of power sensitivity and noise spectrum.Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía, mediante el proyecto P09-TIC-5268. Universidad de Málaga - Campus de Excelencia Internacional Andalucía Tec

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

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

Butler Matrix Based Six-port Passive Junction

In this work we propose the utilization of the Butler matrix as a six-port I/Q demodulator. The inherent symmetry of its topology allows to overcome the intrinsic amplitude and phase imbalances of the traditional approaches making it more suitable for the design of high performance six-port networks. To demonstrate the validity of the proposal a Butler matrix has been designed covering the complete UWB band and its results are compared with the traditional approaches

Extreme eigenvalue distributions of Jacobi ensembles: New exact representations, asymptotics and finite size corrections

Let $\mathbf{W}_1$ and $\mathbf{W}_2$ be independent $n\times n$ complex central Wishart matrices with $m_1$ and $m_2$ degrees of freedom respectively. This paper is concerned with the extreme eigenvalue distributions of double-Wishart matrices $(\mathbf{W}_1+\mathbf{W}_2)^{-1}\mathbf{W}_1$, which are analogous to those of F matrices ${\bf W}_1 {\bf W}_2^{-1}$ and those of the Jacobi unitary ensemble (JUE). Defining $\alpha_1=m_1-n$ and $\alpha_2=m_2-n$, we derive new exact distribution formulas in terms of $(\alpha_1+\alpha_2)$-dimensional matrix determinants, with elements involving derivatives of Legendre polynomials. This provides a convenient exact representation, while facilitating a direct large-$n$ analysis with $\alpha_1$ and $\alpha_2$ fixed (i.e., under the so-called "hard-edge" scaling limit); the analysis is based on new asymptotic properties of Legendre polynomials and their relation with Bessel functions that are here established. Specifically, we present limiting formulas for the smallest and largest eigenvalue distributions as $n \to \infty$ in terms of $\alpha_1$- and $\alpha_2$-dimensional determinants respectively, which agrees with expectations from known universality results involving the JUE and the Laguerre unitary ensemble (LUE). We also derive finite-$n$ corrections for the asymptotic extreme eigenvalue distributions under hard-edge scaling, giving new insights on universality by comparing with corresponding correction terms derived recently for the LUE. Our derivations are based on elementary algebraic manipulations, differing from existing results on double-Wishart and related models which often involve Fredholm determinants, Painlev\'e differential equations, or hypergeometric functions of matrix arguments.Comment: This work was supported by the HKTIIT (HKTIIT16EG01) and the General Research Fund of the Hong Kong Research Grants Council (16202918

Caracterización y Simulación de un Diodo Schottky de Microondas

Presentado en el XXVIII Simposium Nacional de la Unión Científica Internacional de Radio. URSI 2013, Santiago de Compostela, 11 al 13 de septiembre de 2013.Microwave diode models included in commercial simulators use a large set of parameters, so they are often difficult to set up in order to match the actual response of a specific device. In this paper a simple model for a zero-bias microwave Schottky diode is presented. Noise characteristics are determined by measurements and then incorporated to the large signal model offered by the manufacturer in the diode datasheet. Using this model a diode power detector in large signal operation is simulated with commercial software, achieving excellent agreement with the measurement results, both in terms of power sensitivity and noise spectrum.Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía, mediante el proyecto P09-TIC-5268. Universidad de Málaga - Campus de Excelencia Internacional Andalucía Tec