Navegando por Assunto "Canal de retorno"

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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)
Estratégias baseadas em análise multicritério para seleção de tecnologia de acesso de primeira milha em padrão ISDB-T
(Universidade Federal do Pará, 2012-11-23) SERUFFO, Marcos César da Rocha; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
This thesis proposes the development of a planning strategy that combines: load characterization of a typical Digital TV, extraction of a weight vector from belief networks, and multicriteria decision making with analytical methods (TOPSIS and ELECTRE III), providing decision support at the service providers; in order to enable the optimal choice for the return channel technology (ADSL2 +, PLC, WiMAX and 3G), considering the typical load of an interactive Digital TV scenario, standard ISDB-T. The proposed strategy has five steps: definition of return channels and performance metrics; performance measurements of access technologies in real scenarios; scenario simulation; apply correlation techniques to generate the weight vector; and application of analytical decision making for choosing the best technology to be implemented in a given scenario. As main result a generic and flexible model is presented, validated with a case study for ordering the preference of the evaluated technologies.