Navegando por Assunto "WiMAX - Interoperabilidade mundial para acesso de microondas"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Avaliação da tecnologia femtocell como canal de retorno para TV digital
(Universidade Federal do Pará, 2013-08-26) COSTA, Allan Barbosa; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Traffic measurement on Digital TV interactive applications for fourth generation networks, especially WiMAX and femtocell, has been a challenge to researchers around the world. The traffic pattern of an interactive application on the Brazillian System of Digital TV (SBTVD) was identified. Simulations on a wireless network were carried out using data obtained of traffic analysis. In this work a WiMAX and a femtocell network were chosen to simulate the return channel of a Digital TV application on a WMAN (Wireless Metropolitan Area Network). In order to reduce signal attenuation, femtocell arises as a promising solution, reducing macrocell usage, as femtocells cover indoor environments. The simulations is this work were executed using OPNET software. Through them it is possible to estimate the feasibility of femtocell and WiMAX technologies as return channel for Digital TV.
Acesso aberto (Open Access)
Um modelo cross layer para predição de parâmetros de desempenho em redes sem fio baseados em OFDM
(Universidade Federal do Pará, 2011-11-28) MACHADO, Victor de Andrade; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
This dissertation work aims to create a mathematical model that performs the adjustment of data obtained from measurement campaigns using a prototype of a WiMAX scenario. The measurement campaigns were made at the Federal University of Para, using equipment which would enable such work. WiMAX antennas were used, one as a server, located in the building up of High Performance Network Planning Laboratory (LPRAD), and the other receiver, who was on top of a vehicle so that the points were collected. The adjustment method used was the Linear Least Squares. Through the collected data, the method is applied and their behavior is studied, checking how the optimization was effective in the cases presented. The use of relevant technology such as Internet access in some programs like NAVEGAPARÁ, the search for improvements or creation of propagation models and cross-layer analysis of the metrics used in the work, as the influence of signal to noise ratio in the loss frame, are motivating factors for this dissertation research.
Acesso aberto (Open Access)
Projeto de antenas multibandas integradas para terminais 4G
(Universidade Federal do Pará, 2014-02-26) FERREIRA, Hélio Renato Oeiras; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This paper presents a design and analysis of a planar monopole antenna operating in multiband frequencies of 2000 MHz, 2500 MHz and 3500 MHz for use in 3G and 4G mobile devices. Among these bands are contained 3G (1895-2165 MHz), 4G (2500-2690 MHz) and 4G (3400-3600 MHz) spectra used by LTE and WIMAX 3.5. For the development of this study was taken as reference Hua-Ming Chen’s dual-band antenna designed to operate at ISM systems (1800 MHz), wireless networks and Bluetooth (2400 MHz). The project proposed in this work is a modification in the structure of the dual-band antenna adapted for simultaneous triple resonance frequencies used in 4G mobile networks. To achieve the proposed objective was used to simulate the CST® MICROWAVE STUDIO software based on the Finite Integration method in Domain; the simulations were done in the time domain. After obtaining satisfactory simulated results, a prototype antenna was built to test and measurement; the presented results are consistent with those obtained in the simulation, which validates the proposed method.