XXXI Simpósio Brasileiro de Telecomunicações

Most of studies in cognitive radio have considered that the transmission of secondary users is not allowed within the sensed band during the sensing period. This consideration leads the CR to under utilize the available spectrum while sensing the radio frequency environment. This paper brings the performance of the continuous sensing technique on CR...

In this paper, we propose an efficient pilot-assisted technique for the estimation of very-large MIMO (multiple-input multiple-output) channels exploiting the inherent sparsity of the channel. We first obtain an appropriate sparse decomposition model from a virtual channel representation of the very-large MIMO channel. Based on this model, we capitalize on...

The Sparse Component Analysis is one of the most used techniques for handle the source separation problem. In this paper, a technique based in atomic decompositions, is used in the identification of a mixture system. If isolated excerpts of the sources are available, we show that using adapted dicionaries can imply a better (with a inferior MSE in,...

In techniques that are based on the texture and depth information to generate virtual view, the depth maps have to be represented with a reduced number of bits without compromising the visual quality of virtual view. The coding of maps using flexible segmentation and approximation of the prediction residuals by linear functions (LFP) has achieved...

Este artigo apresenta uma proposta para implementação de um Proxy Gateway Manager, desenvolvido em plataforma aberta, para gerência de Redes Sensores Sem Fio (RSSFs) integrado ás redes TCP/IP. O ambiente proposto é gerenciado por uma Estação de Gerência de Rede com SNMP. Para validação, foi montado um sistema para monitorar a RSSI de uma rede de...

This paper presents a comparative study of performance metrics applied to color images with invisible digital watermark. The imperceptibility of the watermark and the distortion that can cause in the image are important factors in the evaluation of the invisible watermark insertion algorithms and usually this is done through the performance metrics....

Este artigo apresenta simulações de parâmetros primários para cabos de cobre em frequências até 100 MHz. Especificamente, dois simuladores numéricos – CST Cable Studio 2012 e OptEM – foram comparados com um modelo de cabo analítico. Os resultados indicam que o CST Cable Studio 2012 não reproduz o efeito de proximidade. O OptEM, sendo um simulador...

In this article we consider the uplink scenario of a wireless communication system where M active users simultaneously communicate with a base station equipped with an array of K receive antennas. A method based on tensor modeling is proposed to address the problem of blind spatialsignature estimation. The proposed method is based on exploiting multiple...

O desempenho da modulação codificada em treliça multidimensional 4D-8PSK TCM em canal não linear é analisado por simulação, utilizando um amplificador à válvula de ondas progressivas (TWTA) comercial para o modelamento das distorções AM/AM e AM/PM. Os resultados são avaliados por meio de comparações com outras modulações, enfatizando o impacto na taxa de...

In this paper, we present the Compressive Sensing technique evaluating the quantization effects on image reconstruction by having the L1-norm and the TV-norm minimizations as reconstruction techniques.