Horacio Tertuliano S. Filho

Aspectos gerais da teoria da difração sob o ponto de vista de um princípio de incerteza

Da-se o nome difracao a um conjunto de fenomenos de natureza inerentemente ondulatoria caracterizado pelo encurvamento, alargamento espacial e interferencia de ondas que podem ser ondas mecânicas (som, ondas de agua), eletromagneticas ou ondas de materia no caso da mecânica quântica. Neste trabalho a difracao e abordada sob o ponto de vista de um principio de incerteza e da superposicao e interferencia de solucoes de ondas planas.

Mobile Coverage in Curitiba, Brazil: Methodology for Measuring the Quality of Services Using LTE

Curitiba is a city in south Brazil with an estimated population of 1.8 million inhabitants [3]. The teledensity in this city is over 1.2 cellular for each person and, four players, actually are working with Long Term Evolution (LTE) in the city. However, the quality of the LTE cell coverage has not yet reached the standard of the Third Generation Partnership Project (3GPP) group. Considering the growing demand for better quality of service provided by telecom operators, this study aims to develop a methodology for analyzing the quality of cellular LTE coverage in Curitiba that can easily be extended to any other big city in Brazil, since we consider a dense urban region, in the frequency range of 2600 MHz and a bandwidth of 20 MHz. The methodology includes conducting a proper drive test in a commercial network with the processing of data obtained through the commercial software, as well as developing a spreadsheet to perform a theoretical project for the purpose of comparing and validating the methodology.

Parameters Fitting to Standard Propagation Model (SPM) for Long Term Evolution (LTE) using nonlinear regression method

This paper intends to propose a model of adjustment to the Standard Propagation Model (SPM) for personal mobile communication to fourth generation networks, known as Long Term Evolution (LTE), being implemented in Brazil, whose complexity of urban and suburban environments determine a particular parameterization, in order to plan and design more efficiently and optimally these networks, as well the rational use of available resources. According to a campaign of measures carried out by a local operator, the SPM model was adjusted using a method of nonlinear exponential regression, which showed satisfactory results to evaluate the coverage area and can identify shadow areas not covered in conventional models. The results were evaluated using tools error analysis of statistics, demonstrating that the deviations of the simulations show a significant improvement in performance.

A Study of the Mesh Topology in a ZigBee Network for Home Automation Applications

Technological advances allowed in recent years the development of numerous applications and systems that improve peoples lives in various sectors, especially the home automation. Already the wireless communication has become dominant in the data transmission segment to allow greater adaptability and flexibility in access to multiple devices among users, and networks based on wireless protocols (IEEE 802.11) widely used. However other protocols such as ZigBee (IEEE 802.15.4) appear quite attractive relative to price, power consumption, and reduced implementation of electronic projects. This study aims to evaluate the performance of the mesh topology operating modes in a ZigBee network. Results showed that there is a performance difference between the operation modes of the mesh topology. In the residential environment were carried out communication tests between the ZigBee network devices, where the results were acceptable to the tested environment. Distances and response times between the ZigBee network devices were within the minimum quality requirements for the operation of home automation project.

Performance Analysis of 380-470 MHz Band Radio Systems for Brazilian Public Security Use

The design of intelligent safety systems and interfaced that allow the reliable products and robust enough for use in security, necessary for the ordinary citizen, has been the subject of much discussion and study by the Brazilian federal Government, before the receipt of relevant sportive events. Sensitive sectors and permanent presence as notable are security and defense in the face of challenges and expectations expected. The challenge for the design of these systems is to develop networks of different protocols that are interoperable and shared. Within this context is that this article seeks to contribute to a globally technologies used in Comparative Public Safety radio communications (APCO-25 System, TETRA and TETRAPOL) showing a real case study with the three communication technologies tests carried out in accordance with the national agency of telecommunications - ANATEL and the Ministry of justice through the National Secretariat of Public Security.

Efficiency, Reliability and Availability for 3,5 GHz Transmission Systems

The problem quality of service (QoS efficiency x reliability x availability) of system of transmission it is a of factors that demand more efforts of engineering be attended. The in this case efficiency may be associated the control of the frequency spectrum in line with existing laws and do not to control of transmission rates, losses and delays of package that will be controlled, by the traffic brought, among others. The reliability translates by the perfect geometry of the constituent elements of it, and finally the availability is associated with the limit fault allowed for system in operation. The innovative proposal of this article it is rigorous combination of these factors in the process of design multipoint transmission system and multi-channel so that if obtain data Minimum QoS required by the regulatory agency for telecommunications services of Brazil for systems operating in the 3.5 GHz band currently in phase of standardization in Brazil.