Navegando por Assunto "Quality of service (QoS)"

Agora exibindo 1 - 5 de 5

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)
Clustering-driven equipment deployment planner and analyzer for wireless non-mobile networks applied to smart grid scenarios
(Universidade Federal do Pará, 2018-03-16) VRBSKÝ, Ladislav; SILVA, Marcelino Silva da; http://lattes.cnpq.br/7080513172499497
The modern power grids, known as smart grids, rely on various advancements, one of them being the introduction of bi-directional communication. In some cases, data exchanged in the network is of critical importance. The data transmissions need to meet speci c delay limits set by the regulatory agencies in order for the smart grid to function properly. Meeting these standards allows the use of new applications of monitoring, control and system protection, resulting in a more e cient, stable and environment-friendly system. This thesis presents a methodology for analysis and planning of wireless communication networks for smart grid, which uses a clustering algorithm to determine the optimal positions of the routers and gateways of the network to be installed. After, it calculates the delay for each Intelligent Eletronic Device that is a network subscriber. This way, an analysis can be made to obtain the Quality of Service requested for a speci c network setup in a speci c scenario. The results obtained in the performed case study show that it is possible to achieve a network topology that satis es the maximum delay requirements of 100% of its subscribers, using WiMAX or a combination of Wi-Fi and WiMAX. Also, the thesis explores a restricted communication mode that can temporarily suspend the transferences of non-critical data. In most scenario con gurations, the restricted mode delivers all the data within the maximum delay. The software implementation of the proposed model is made publicly available under open-source license, so that anyone, including researchers, or private and public companies, can take advantage of it. The model presented in this thesis is customizable, allowing the use of other technologies and be used with other networks, including scenarios that are not related to smart grid.
Acesso aberto (Open Access)
Green markov - uma abordagem híbrida de política markoviana e simulação discreta para planejamento de alocação de usuários em redes macro-femto
(Universidade Federal do Pará, 2014-10-31) CARDOSO, Jorge Amaro de Sarges; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
The use of voice and data communication via mobile devices has increased significantly in recent years. This expansion brings some difficulties such as: continuous expansion of network capacity and energy efficiency. In this context, has been consolidating the concept of Green Networks, which focuses on the effort to energy saving and CO2 reduction. Thus, this paper proposes validate a model of a policy based on Markov decision process to optimize energy consumption, QoS and QoE, in the allocation of macrocell and femtocell users in networks. For this the model was inserted into the network simulator NS-2, combining the Markov analytical solution to the characteristic flexibility of discrete simulation. From the results presented in the simulation, the policy obtained significant savings in energy consumption, improving energy efficiency by up to 4%, and improve the quality of service in relation to the macrocell and femtocell networks, demonstrating effective in order to directly change the metrics of QoS and QoE.
Acesso aberto (Open Access)
Planejamento de redes de comunicação sem fio para ambientes indoor considerando aplicações multimídia: abordagem híbrida - simulação e medição
(Universidade Federal do Pará, 2014-08-29) BRAGA, Allan dos Santos; FRAIHA, Simone da Graça de Castro; http://lattes.cnpq.br/6398509825377181; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Wireless technologies have evolved rapidly in recent decades. It is an efficient alternative to transmit information, whether data, voice, video and other network services. Knowledge of the propagation process of this information in different environments is a factor of great importance for the planning and development of wireless communications systems. Because of the rapid progress and popularization of these networks, the services offered become more complex and therefore need requirements for qualities that are offered to the end user in a satisfactory manner. Because of this, it is necessary to designers of these systems, a methodology that provides a better assessment of the indoor environment. This assessment is made by analyzing the coverage area and the behavior of the metrics of multimedia services anywhere in the environment that is receiving the service. The work in this study intends to evaluate a methodology for the prediction of quality metrics experience. For this, measurements of video streaming campaigns were conducted in a wireless network and network parameters (packet/frames jitter and packet/frames loss) and some quality parameters of experience (PSNR, VQM and SSIM) were evaluated. The results showed good agreement with literature data and with measurements.
Acesso aberto (Open Access)
Predição de qualidade de experiência em redes wimax em aplicações de video baseada em aspectos de qualidade de serviço
(Universidade Federal do Pará, 2011-07-02) OLIVEIRA, Rosinei de Sousa; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The increasing use of telecommunications services mainly wireless has demanded the adoption of new networking standards that offer higher data rates and reach a larger number of users. In this sense the IEEE 802.16 standard, which is based WiMAX emerges as a potential technology for providing broadband in the next generation of wireless networks, mainly because it offers Quality of Service (QoS) for voice streams natively, data and video. Regarding the video-based applications, there has been a steady growth in recent years. In 2011 it is expected that this type of content exceeds 50% of all traffic from mobile devices. Applications like video have a strong appeal to the end user who is who in fact should be the evaluator's level of perceived quality. Given this, we need new forms of performance assessment that take into account the perception of the user, thereby complementing traditional techniques that rely only on network aspects (QoS). In this sense, there was the performance evaluation based on Quality of Experience (QoE) assessment where the end user rather than the application is the main parameter measured. The results of investigations QoE can be used as an extension over the traditional methods of QoS, and at the same time provide information regarding the delivery of multimedia services from the viewpoint of the user. Examples of control mechanisms that may be included in networks that support new approaches are QoE routing process of selecting the base station and traffic conditioning. Both methods of evaluation are complementary, and if used in combination can generate a more robust assessment. However, the large amount of information hinders this combination. In this context, this paper's main objective is to create a methodology to predict video quality WiMAX networks with combined use of simulation techniques and Computational Intelligence (CI). From QoS and QoE parameters obtained from the simulations will be performed to predict the future behavior of the video with the use of Artificial Neural Networks (ANN). On the one hand the use of simulations allows a range of options such as extrapolation of scenarios to mimic the same real-world situations, the IC techniques allow faster analysis of the results so that they are made predictions of future behavior, correlations and others. In the case of this work, we chose to use RNA as it is the most used technique to predict the behavior, as is being proposed in this dissertation.