João Furtado de Souza

Level analysis of a digital TV signal using the tool moving average

With the implantation of digital TV system in Brazil since from 2007, several research groups have been created to study the performance of digital TV signal in several areas in the country. This study, in the north region, due their peculiarities (forests, rivers, buildings, etc..), is a very relevant component. In this work a study was carried the signal level with distance using a statistical method, moving average, and the Pearsons correlation factor. The results compared with the experimental results showed good agreement. The average error was 3.88 dB and standard deviation 3.90 dB.

Propagation Path Loss through the Urban Foliated Semi-confined Environment Using Parabolic Equations

A model to predict the propagation path loss through the urban foliated semi-confined environment using parabolic equations (PE) is proposed. For the solution of PE the Crank-Nicolson an implicit scheme of finite difference is used. It is considered for this case the propagation in 15 deg to the paraxial direction. The model consists of an array of rectangles (representing the buildings) and an array of cylinders (representing the trunks of the trees). A campaign of measurements taken in an urban street enclosed by buildings and high trees at 890.4 MHz was carried out to validate the model. Numerical examples demonstrate the computational efficiency of the proposed method

Application of Parabolic Equation and Hata-Davidson propagation models for digital TV coverage prediction

In this paper the formalism of Parabolic Equations for narrow angles, a statistical method, the Moving Average and a empirical model, the Hata-Davidson, were used for to study on the quality of digital TV signal in the UHF band, and were compared with the measured in an heterogeneous environment, because it has areas with large buildings mixed with Amazonian vegetation. The implicit finite difference scheme of the Crank-Nicolson type was applied in order to get the solution of the Parabolic Equation. The propagation was considered in 15° in the direction paraxial. The results showed that the formalism of Parabolic Equations can be used to study the quality of digital TV signal. The average error was 1.62 dB and standard deviation 4.13 dB.

Propagation path loss in mixed-path environment using narrow angle and wide-angle Parabolic equations

A model to predict the propagation path loss through the urban foliated semi-confined environment using parabolic equations (PE) is proposed. For this case the propagation in 15° to the paraxial direction and the implicit finite differences scheme of the Crank-Nicolson type is used. To wide-angle relative to the paraxial direction propagation (up to 90°), it used mixed Fourier transform and considers the impedance boundary conditions. A campaign of measurements taken in three mixed-path environment was carried out to validate the model. The frequency used was 900 MHz to Benfica and Marituba, and 1.8 GHz for Barcarena. Numerical examples demonstrate the computational efficiency of the proposed method.

A model for radio propagation loss prediction in buildings using wide-angle parabolic equations

This paper propose a model to calculate the path loss propagation in an indoor environment using parabolic equations. To solve the parabolic equation a mixed Fourier transform was used. The impedance boundary conditions, wide-angle relative to paraxial direction of propagation and complex refractive index for the medium were considered. A campaign of measurements was carried out in two environments in 900 MHz and 2.4 GHz frequencies. Simulations with the proposed model showed good agreement with the experimental data and with model of UWB Propagation Channels.

A Model for Radio Propagation Loss Prediction in Buildings using Parabolic Equations

This paper presents a model for propagation loss prediction in indoor mobile communications using parabolic wave equation (PE). The implicit finite differences scheme of the Crank-Nicolson type is applied in order to get the solution of the parabolic equation. The propagation is considered in 15 deg in the direction paraxial. To validate this model, a measurement campaign was accomplished at a typical five floor building of a university using a frequency of 850 MHz. The loss predicted by this model had a mean error of 4.69 dB and standard deviation of 3.85 dB in relation to the measured data