Generating Series and Performance Bounds for Convolutional Codes - Part 2: Transmission on Burst-Error Channels

Cecilio Jose Lins Pimentel

DOI: 10.14209/sbrt.2001.10300100

Keywords:

Abstract

"We present an analytical method for evaluating the performance of a communication system that employs a convolutional code, a block interleaving with finite interleaving depth, a binary channel that exhibits statistical dependence in the occurrence of errors, and a decoder that implements the Viterbi algorithm with Hamming metric. The main idea is to apply combinatorial methods to derive a formula for bounds to first-event and bit error probabilities in terms of coefficients of a generating series. The method is used to investigate the tradeoff between coding parameters and interleaving depth to achieve a required performance."

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Generating Series and Performance Bounds for Convolutional Codes - Part 1: Transmission on Memoryless Channels

Cecilio Jose Lins Pimentel

DOI: 10.14209/sbrt.2001.10300101

Keywords:

Abstract

"Performance bounds for convolutional codes over memoryless channels are commonly measured using the distance weight enumerator T(x,y), also referred to as the generating series or the transfer function, of the code. In particular, bounds to the bit error probability are computed using the first few terms of the series expansion of {dT(x,y)/dy}_{x=1}. In this paper we present an efficient algebraic method to obtain this truncated series. We also propose a iterative procedure to compute the truncated T(x,y) that discards, at each step, all paths with Hamming weight higher than a given order."

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Novos Códigos Espácio-Temporais para Canais com Desvanecimento

Luiz Guedes Caldeira, Cecilio Jose Lins Pimentel

DOI: 10.14209/sbrt.2001.10300168

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Abstract

"Este artigo propõe, através de uma busca computacional sistemática, novos códigos espácio-temporais que transmitem múltiplos sı́mbolos por antena em cada transição de estados. Neste caso, o espalhamento da redundância de codificação não limita-se apenas às transmissões paralelas por múltiplas antenas, mas também ao longo das transmissões seriais em cada antena. Os códigos propostos têm ganho máximo de diversidade e apresentam ganhos de codificação em relação aos códigos espácio-temporais propostos recentemente por Tarokh et al. e Baro et al."

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Self-Similar Lan/Wan Traffic Model: a Survey

Anibal Dario Angulo Miranda

DOI: 10.14209/sbrt.2001.10400149

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Abstract

"Results that can be considerate as classicals from self-similar model paradigm are showed in this work. All measurements and results presented here were based on data traffic traces gathered in our network gateway using a simple yet reliable and efficient method. Several statistical methods, to infer an unbiased and well defined Hurst parameter, are also re- viewed. Some important queuing performance measurements with both fractal and Markovian-type models are also presented."

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Uma Proposta de Arquitetura IP para Backbones de Alta Velocidade

Roberto Cesar Betini, Nelcy Keffer Camiña

DOI: 10.14209/sbrt.2001.10500199

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Abstract

"This article presents a purpose of QoS for IP networks. It shows how Internet Service Providers can guaranty QoS, according with the type of flow being controlled. We have described how a high speed network would be implemented without a significant change in the actual internet architecture. Finally, we discussed the internet need to have to provide bandwidth channels enough to guaranty a given QoS and we have suggested the use of IPv4 over DWDM to supply this need in a cost effective way."

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IP/WDM - a União de Tecnologias Robustas na Era da Convergência

Silvio M. Rezende, Roberto Cesar Betini, Nelcy Keffer Camiña

DOI: 10.14209/sbrt.2001.10500222

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Abstract

"The following discussion provides some background on why wavelength division multiplexing (WDM) is an important innovation in optical networks and what benefits it can provide. We begin with a high-level view of the segments of the network and forces that are driving the revolution in fiber optical networks. We then examine the differences between traditional network technologies and the evolution need to employ the Internet Protocol (IP) over WDM."

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Sistemas Ópticos Amplificados Solitônicos

Crisluci Karina S. Santos, Humberto César Chaves Fernandes

DOI: 10.14209/sbrt.2001.10600112

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Abstract

"comportamento de sólitons em sistemas de transmissão de longa distância. Um dos principais fatores limitantes do desempenho destes sistemas é o ruído de emissão espontânea amplificada – ASE, introduzido pelos amplificadores presentes na transmissão. Os efeitos do ruído ASE e sua interação com os sólitons são analisados graficamente em curvas de 2 e 3D."

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Study on Superconducting Microstrip Antenna Array Using TTL Analysis

Rogério Torres Carvalho Filho, Eritônio De Figueiredo Silva, Humberto César Chaves Fernandes

DOI: 10.14209/sbrt.2001.10600124

Keywords: Microstrip antenna array TTL method Wireless

Abstract

"For the microstrip patch resonator, as a planar antenna of a microstrip, a set of equations that represents the electromagnetic fields in the x and z direction as function of the electric field in the y direction are obtained applying the transverse transmission line method. This method is very suitable at microwave and antenna applications, and gives accurate complex resonant frequency which contributes definitively to obtain higher precision antenna parameters. For each type of array is calculated the array factor, considering the excitation, phase and the relative displacement between the elements as well as the dimensions and number of elements."

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Analysis of Millimeter Wave Resonator

Humberto César Chaves Fernandes, Magno Cavalcante Da Silva

DOI: 10.14209/sbrt.2001.10600127

Keywords:

Abstract

"The direct and efficient Transverse Transmission Line (TTL) method is used to analyze the unilateral fin-line resonator. In this method the Maxwell's equations in Fourier transformed domain, are firstly used to obtain the electromagnetic fields in terms of the transversal electromagnetic fields. An inhomogeneous equation system is obtained, in which the current densities in the conductor fins are related to the electric fields in the slot. The TTL method in conjunction with the Galerkin’s procedure and Parseval’s relation are applied to obtaining a homogeneous equation system with two variables. The determinant of this system gives the complex resonance frequency."

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Discretization in Triangular Microstrip Resonators

Humberto César Chaves Fernandes, Carlos Barboza Beltrão

DOI: 10.14209/sbrt.2001.10600226

Keywords:

Abstract

"The triangular microstrip resonator with steps in the width is a way to simulate the triangular form by the triangular discrete, its analyze is made using the full wave and concise Transverse Transmission Line (TTL) method in the Fourier Transformed Domain (FTD), in conjunction with the Moment Method. Numerical results of the resonance frequency are presented in graphics in 2D and 3D with the use of the FORTRAN Power Station and MATLAB languages."

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