VII International Telecommunications Symposium

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Fiber Bragg Grating Compression-based Tuning Device for Reconfigurable OADM
Roberson A. Oliveira, Carlos E. N. Mayer, Alexandre A. P. Pohl, Jucélio T. Pereira

DOI: 10.14209/sbrt.2010.11
Keywords: Fiber Bragg Gratings tuning device OADM
Abstract
In this work a fast Bragg grating-based tuning device, working according to the mechanical compression of the fiber, is demonstrated. The device achieves a tuning range of 10 nm and presents tuning speeds up to 15 nm/ms. The component can function as the basic element in wavelength routers and add-drop multiplexers.

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Microstrip Antennas Array with patch superconductor at High Temperature
Hugo Michel Câmara de Azevedo Maia, Humberto César Chaves Fernandes, Leonardo Martins Caetano, Marinaldo Pinheiro de Sousa Neto

DOI: 10.14209/sbrt.2010.12
Keywords: Temperature antenna microstrip superconductor patch antenna array linear
Abstract
New results and the analysis of the resonance frequency and pattern fields of microstrip antennas array, with superconductor patch for different very high critical temperatures, are presented. The linear superconducting rectangular microstrip antennas array uses the new materials Sn5InBa4Ca2Cu10Oy at temperature of 212 K, conductivity of 1.88x105 S/m and Tl5Ba4Ca2Cu10Oy at temperature of 233 K with conductivity equal 2.0x105 S/m. The concise full wave Transverse Transmission Line (TTL) method, is used in the analysis. New results as functions of the temperature, and resonant frequency as functions of the various antenna parameters, for different superconductor are presented.

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Rounded Patch Antenna with T-Shaped Probe Feeding and Shorted Wall
F. da Silva Paixão, M. N. Kawakatsu, V. A. Dmitriev

DOI: 10.14209/sbrt.2010.13
Keywords: Patch antenna T-shaped probe feeding shorted wall broadband
Abstract
In this work, a modified patch antenna with broad bandwidth and small size is proposed and investigated. Instead of rectangular patch of a known antenna we use a rounded patch. This modification increases significantly the upper frequency edge of the operating band. This allows one to obtain a -10 dB return loss bandwidth of 72 % and to flatten the gain characteristic. In our study, we use the parametric optimization of geometry of the antenna

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A ew Multifractal Traffic Model and Its Impacts on Buffer Queueing Performances
Jeferson Wilian de Godoy Stênico, Lee Luan Ling

DOI: 10.14209/sbrt.2010.14
Keywords: Multiscale Traffic Modeling Loss Probability Network Traffic
Abstract
In this paper, we propose a new analytical expression for estimating byte loss probability at a single server queue with multi-scale traffic arrivals using Pareto distribution. In order to make the estimation procedure numerically tractable without losing the accuracy, we assume and demonstrate that an exponential model is adequate for representing the relation between mean square and variance of Pareto distributed traffic processes under different time scale aggregation. Extensive experimental tests validate the efficiency and accuracy of the proposed loss probability estimation approach and its superior performance for applications in network connection with respect to some wellknown approaches suggested in the literature

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A Robust MERRY Channel Shortening Technique for OFDM Systems in PLC Environment Corrupted by Impulsive Noise
Alam Silva Menezes, Moisés Vidal Ribeiro

DOI: 10.14209/sbrt.2010.15
Keywords:
Abstract
This contribution introduces a robust version of the multicarrier equalization by restoration of redundance (MERY) algorithm for data communication through power line communication (PLC) channel corrupted by impulsive noise. The novelty is the introduction of a nonlinear and differentiable function into the cost function of MERRY algorithm. As a result, the proposed and named robust (R)-MERRY algorithm is less sensitive to the presence and hardness of impulsive noise. Simulation results reveal that bit error rate (BER) performance improvements can be attained in PLC scenarios

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Modulations for Large Signal Constellations Coming from Embedding of Complete Graph
João de Deus Lima, Luana Priscilla R. C. de Lima, Wilken Charles Dantas de Melo

DOI: 10.14209/sbrt.2010.16
Keywords:
Abstract
The integrated system of data transmission, encoding, modulation and block channels are projected in dependent ways with the purpose of getting an integrated action from those elements, and the elimination of additional devices with incompatibility treatment, caused by inadequate choice of some those components. In this system, the modulation and encoding projects take place in topological spaces (Ω; d), where Ω is Riemannian manifolds and d is a metric on Ω, which the discrete memoryless channel Cm, like a graph, is embedded. For each embedding Cm ,! Ω, it’s possible to determine accurately a topological modulation project on Ω, in the sense of knowing the decision regions (or Voronoi’s regions) of each constellation signal. The paper’s purpose is to identify topological projects of modulation on surfaces for large constellations, mainly the regular modulations. The procedures to obtain these projects are based on the method of the current graph developed by Gustin and Youngs and used in the proof of Color Graph Conjecture by Heawood.

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Synchronization of Legacy 802.11a/g Devices Operating in IEEE 802.11n Networks
Roger Pierre Fabris Hoefel, André Michielin Câmara

DOI: 10.14209/sbrt.2010.17
Keywords: 802.11n 802.11a/g synchronization
Abstract
It is investigated the performance of legacy IEEE 802.11a time synchronization algorithms when the synchronization preamble is transmitted by IEEE 802.11n devices with multiple transmitting antennas using cyclic shift diversity. It is concluded that the backward compatibility is achieved when the time synchronization is implemented using an auto-correlation maximum normalization metric.

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A Packet Distribution Traffic Model for Computer Networks
Ewerton Castro, Ajey Kumar, Marcelo S. Alencar, Iguatemi E. Fonseca

DOI: 10.14209/sbrt.2010.18
Keywords: Self-similar Computer Network Internet Traffic File Size Distribution
Abstract
The traditional traffic models which are based on conventional telephone traffic are not suitable for modeling selfsimilar traffic on computer networks. Therefore, emphasis has been put on self-similarity characteristics. This paper presents a model which can be used to compare, simulate and estimate the packet traffic distribution on computer networks.

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Nanophotonics in Modern Communication Systems – Feasibility of Plasmon-Polariton Waveguides in Optical Networks
Anderson O. Silva, Jorge A. Macedo, Victor Dmitriev, André Lages

DOI: 10.14209/sbrt.2010.19
Keywords: Nanophotonics surface-plasmon-polaritons subwavelength waveguiding structures
Abstract
Use of surface-plasmons-polaritons has become a potential way to develop optical components below the diffraction limit. This paper reports the feasibility of some plasmonpolariton waveguides in optical communication systems. Combinations of metal elements of different geometry are theoretically analyzed. They can serve as building blocks in future nanophotonic systems. The spectral responses of these structures show they can be used as frequency selective components in optical communication windows for wavelength division multiplex applications.

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On Indoor Coverage Models for Industrial Facilities
Cassio Bento Andrade, Roger Pierre Fabris Hoefel

DOI: 10.14209/sbrt.2010.20
Keywords: industrial WLANs 802.11 coverage
Abstract
It is shown analytical and measurement results in order to compare five different indoor path loss propagation models in industrial environments: one-slope; dual-slope; partitioned; Cost-231 multi-wall model and average walls. It is concluded that the dual slope propagation model allows a better estimation among the selected models because the propagation loss rate increases abruptly beyond a certain distance from the transmitter in large industrial environments.

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