XXXVIII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

This paper proposes a general-purpose radar simulation tool based on the path tracer Cycles used in Blender, an open-source 3D computer graphics software. The scenarios, object's geometry, and materials can be defined within Blender. The propagation of waves in the scenery is simulated by the Cycles renderer, so that a second computational tool, such as...

In centralized cooperative spectrum sensing with decision fusion, secondary user terminals sense a radio frequency band, sending to a fusion center the local decisions made based on local test statistics. At the fusion center, the global decision on the occupation state of the sensed band is made based on the logical combination of the received local...

This paper considers second order statistics for the composite κ-μ fading model. More specifically, level crossing rate and average fade duration are calculated, and two formulations are offered: exact and approximate. The exact formulation is given in integral form, and the approximate one is written in terms of the Fox H-function, and also expressed as...

We analyze the high-SNR behavior of the level crossing rate and average fade duration for a variable-gain amplify-and-forward relaying system composed of an arbitrary number of hops under Rayleigh fading. Most studies on the second-order statistics of multi-hop amplify-and-forward relaying assume fixed gains at the relays and analyze the end-to-end...

M2MMAC is a MAC protocol for ad hoc wireless networks based on the IEEE 802.11 standard. It uses multiple channels to make feasible many-to-many communication for the purpose of increasing network throughput. In this paper, M2MMAC is described, and new functionalities are proposed for the protocol to deal with packet reception failures. Moreover, the...

Antenna arrays are very used in system that the transmission's direction has to be decided automatically. In this project, a 16x16 square array using phase shifters capable of forming discrete beams and the beam distribution obtained according to requirements are analyzed. In addition to the beam functional analysis, the array is also analyzed by some...

Nonlinear phase-noise induced by the Kerr effect is the main nonlinear impairment in single-channel coherent long-reach passive optical networks (LR-PONs). In this work, we explore the capability of the K-nearest neighbors (KNN) algorithm to mitigate this impairment in links with non-negligible fiber dispersion. Simulation results show that when...

Este trabalho apresenta uma investigação sobre o uso de espectrogramas de fase aplicados a sistemas de reconhecimento automático de fala (automatic speech recognition - ASR) baseados em redes neurais profundas (deep neural network - DNN). Particularmente, visando à obtenção de atributos discriminativos robustos ao ruído, a função atraso de grupo...

Este artigo apresenta um novo algoritmo de seleção de antenas para operação conjunta com algoritmos de conformação de feixe em sistemas de comunicações móveis. Tal algoritmo é formulado visando minimizar os níveis de interferência e atender uma restrição afim relacionada ao número limitado de cadeias de rádio frequência disponível na estação rádio base....

Neste trabalho comparamos três métodos para se determinar a distribuição de uma carteira de renda variável: método Ingênuo onde todas as ações possuem o mesmo peso, Teoria Moderna dos Portfólios e por Referência. O último método foi proposto por nós. Ele tenta replicar o comportamento de uma carteira pulverizada utilizando poucos ativos e foi o que...