Navegando por Assunto "Wi-Fi"

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Acesso aberto (Open Access)
Arcabouço para aprovisionamento de QoS e QoE em redes sem fio heterogêneas WiMAX/Wi-Fi com garantia de equidade entre vazões
(Universidade Federal do Pará, 2011-08-17) VALENTE JUNIOR, Warley Murici; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Recently, the society is living amid an agglomerate of mobile devices with multiple wireless interfaces that allow mobile customers home and business solve routine problems in the shortest time and in several locations. On the other hand, the availability of various wireless access technologies such as Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX) and Long Term Evolution (LTE), provide a heterogeneous scenario with several connectivity opportunities for the user of devices with multiple interfaces. Some of the current challenges in framing the so called Next Generation Networks (NGN) are the development of frameworks and mechanisms that enable both adequate support for Quality of Service (QoS) and Quality of Experience (QoE) for multimedia applications, and assurance equity among throughputs of different applications in a heterogeneous environment. This dissertation proposes a framework for provisioning of QoS and QoE in heterogeneous wireless networks consisting of WiMAX and Wi-Fi networks. Specifically, our solution provides static mapping of QoS between classes of service WiMAX and access categories Wi-Fi. In addition, our proposal also combines features of equity among throughputs with the mapping solution in order to achieve a good tradeoff for both, for the network operator and for the user, through a new methodology for collection and calculation of aggregate throughput and algorithm for Vertical Handover Decision (VHD). The quantitative evaluation of the proposal was carried out using simulation models in Network Simulator (NS-2). The performance results demonstrate the efficiency of the framework in terms of QoS (throughput, average throughput and delay) and QoE (Peak Signal to Noise Ratio, Structural Similarity Index and Video Quality Metric) metrics.
Acesso aberto (Open Access)
New strategies for planning and performance evaluation of wireless networks: case studies based on the cross-layer approach
(2013-06) ARAÚJO, Jasmine Priscyla Leite de; RODRIGUES, Josiane do Couto; FRAIHA, Simone da Graça de Castro; GOMES, Hermínio Simões; COSTA, João Crisóstomo Weyl Albuquerque; CAVALCANTE, Gervásio Protásio dos Santos; FRANCÊS, Carlos Renato Lisboa
The use of wireless local area networks, called WLANs, as well as the proliferation of the use of multimedia applications have grown rapidly in recent years. Some factors affect the quality of service (QoS) received by the user and interference is one of them. This work presents strategies for planning and performance evaluation through an empirical study of the QoS parameters of a voice over Internet Protocol (VoIP) application in an interference network, as well as the relevance in the design of wireless networks to determine the coverage area of an access point, taking into account several parameters such as power, jitter, packet loss, delay, and PMOS. Another strategy is based on a hybrid approach that considers measuring and Bayesian inference applied to wireless networks, taking into consideration QoS parameters. The models take into account a cross layer vision of networks, correlating aspects of the physical environment, on the signal propagation (power or distance) with aspects of VoIP applications (e.g., jitter and packet loss). Case studies were carried out for two indoor environments and two outdoor environments, one of them displaying main characteristics of the Amazon region (e.g., densely arboreous environments). This last test bed was carried out in a real system because the Government of the State of Pará has a digital inclusion program called NAVEGAPARÁ.