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Modern wireless technology calls for high throughput, which can be achieved by large spectral bandwidth, and/or high-order modulation. The in-phase and quadrature (IQ) imbalance is an important factor degrading the transmitter error vector magnitude (EVM), thus limiting the transmitter performance. In order to compensate for the IQ imbalance, a feedback path at the transmitter output is needed to estimate the mismatch. The analog-to-digital converter (ADC) in the feedback path can be power hungry when the signal bandwidth is large. In this paper, we propose a digital IQ imbalance estimator and compensator with 1-bit quantization in the feedback path. We show that the proposed algorithm is valid in terms of estimation convergence and accuracy. Numerical results show that the proposed algorithm achieves comparable estimation accuracy as that using the conventional least mean squares (LMS) method at a much lower cost. [ABSTRACT FROM AUTHOR]

Model comparison problems arise in many fields of science and engineering, including signal processing. In these problems, we wish to quantify how well each of a set of possible models describes a set of observations. Many numerical techniques exist to perform model comparison, but this paper focuses on nested sampling, which is a numerical integration algorithm for evaluating probabilities of models. The original formulation of nested sampling is a strictly sequential algorithm. Most modern advances in computing are via parallel processing, however, and we therefore present a novel method for parallelizing nested sampling. This paper sets out the mathematical foundation for this parallelization, as well as ideas for implementing it. Three examples demonstrate the effectiveness of the present parallel technique in realistic scientific and engineering data analysis problems. [ABSTRACT FROM AUTHOR]

In this paper, we propose extremely accurate, generic, exponential based approximations for the Gaussian Q function. Precisely, we make use of the Romberg numerical integration technique which utilizes the Richardson extrapolation method. This method combines two trapezoidal based approximations thereby yielding accurate yet simple approximations for the Gaussian Q function. We extensively illustrate the significance of the proposed work by comparing it with several other approximations available in the open literature. To show the application of the proposed work in communication theory, as an instance, we further apply the six-term proposed approximation over the versatile κ − μ shadowed fading channel which facilitates the error performance metrics for several wireless communication systems. In addition, the analysis is solidified with the help of computer simulations. [ABSTRACT FROM AUTHOR]

Abstract: The accuracy of pseudo-Zernike moments (PZMs) suffers from various errors, such as the geometric error, numerical integration error, and discretization error. Moreover, the high order moments are vulnerable to numerical instability. In this paper, we present a method for the accurate calculation of PZMs which not only removes the geometric error and numerical integration error, but also provides numerical stability to PZMs of high orders. The geometric error is removed by taking the square-grids and arc-grids, the ensembles of which maps exactly the circular domain of PZMs calculation. The Gaussian numerical integration is used to eliminate the numerical integration error. The recursive methods for the calculation of pseudo-Zernike polynomials not only reduce the computation complexity, but also provide numerical stability to high order moments. A simple computational framework to implement the proposed approach is also discussed. Detailed experimental results are presented which prove the accuracy and numerical stability of PZMs. [Copyright &y& Elsevier]

Abstract: In this paper, we present a new Empirical Mode Decomposition based algorithm for the purpose of QRS complex detection. This algorithm requires the following stages: a high-pass filter, signal Empirical Mode Decomposition, a nonlinear transform, an integration and finally, a low-pass filter is used. In order to evaluate the proposed technique, the well known ECG MIT–BIH database has been used. Moreover it is compared to a reference technique, namely “Christov''s” detection method. As it will be shown later, the proposed algorithm allows to achieve high detection performances, described by means both the sensitivity and the specificity parameters. [Copyright &y& Elsevier]