XXX Simpósio Brasileiro de Telecomunicações

This paper presents a mathematical model for the analysis of losses and dispersion in Bragg fibers with hollow core, based on the transfer matrix method. The paper introduces a strategy for the efficient numerical calculation of the dispersion characteristics of TE 0n , and TM 0n modes. The results are validated by comparison with other methods in...

This paper presents a technique to solve the pro- blem of classifying portions of signal between voice and silence. Surprisingly, the proposed technique is not based on the variation of energy levels over the signal, but on the fundamental charac- teristics that determine the essence of each of these two classes of signals, namely voice and silence....

In this work we assess the impact of channel errors on the perceived quality in high definition videoconference applications. A database containing 31 high definition sequences (1080i) without compression was generated. The set of generated sequences may present backgrounds of different complexities as well as other features, such as number of...

In this article, a new random variable whose distribution closely follows that of the exact distribution of the κ-μ phase distribution is introduced. Whereas the exact statistics is given in an integral form, the approximate one is obtained in a simple formulation that can be computed in a very efficient manner. More interestingly, whereas the exact...

This work aims at the discussion of dielectric antennas ressoadoras. Will be discussed to prepare the ceramic material used in the manufacture of dielectric resonators, which can be used as antennas. The characterization of interest for the transmission in the resonator is made primarily by impedance spectroscopy.

The objective of this work is to study the microwave dielectric properties of the compound BiNbO4 (BNO) with addition of ZnO and discuss the influence of the additions in view of possible applications in dielectric resonators. The BNO ceramic has been produced by the standard method of solid state. The ZnO (3, 5 and 10% by weight) was added in order...

it is necessary to perform a proper planning for an efficient deployment of new infrastructure for transmission of digital television in countries that have adopted such technology. In that sense, the coverage prediction process, which makes use of path loss propagation models, plays an important role. The log-distance path loss model determines...

Delay Tolerant Networks (DTNs) do not have any infrastructure or centralized unit and they allow nodes to exchange messages without routes between them. These points are commonly explored by attackers. One of these attacks is the wormhole. It uses a pre-established infrastructure to force all routes to go through the attacker, forcing a large number...

This paper presents an evaluation of the sym- bol error probability-SEP of θ-QAM scheme under correlated Nakagami-m fading with MRC receiver using Gaussian and Von Mises distributions for modeling the direction of arrival. New mathematical expressions for the SEP are presented and is shown as the magnetic coupling between the elements of the...

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