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This paper presents a numerical analysis of the dispersive effects of light polarization in optical fibers. This study analyzed the behavior of the degree of polarization using the Jones matrix method for modeling the transmission channel as a concatenation of 15 sections of polarization scramblers of PMD and PDL, using the RZ, RZ and CSRZ rectangular digital signals. The numerical simulation considers the effects of first order PMD and PDL.

Due to the increasing demand for data services in mobile networks, operators are observing the quality of data services to degrade as their packed switched (PS) resources become insufficient. Even though there are newer 3/4G technologies available, EGPRS is still a good solution for data services due to ubiquitous coverage, the availability of low cost user terminals and its low deployment costs. Hence, alternative solutions are needed to deal with this increased data traffic without affecting the voice services, which play an important role in GSM networks. This paper presents a study on the usage of the Orthogonal Sub Channels (OSC) for improving voice capacity in order to increase the available resources for PS data services in a GSM/EGPRS network, showing that along with OSC it is possible to increase the number of EGPRS subscribers without extensive capital expenditure, such as increasing the number of radios or acquiring further spectrum resources.

In this paper we analyze spatially multiplexed MIMO systems with limited Channel State Information (CSI) and zero forcing (ZF) linear signal detection technique. Two schemes were considered: Quantization Codebook (QC) and Compressive Sensing (CS). Compressive Sensing is used to generate a reduced CSI feedback to the transmitter in order to reduce feedback load into the system. Performance of the schemes are compared by computational simulations of bit error rate (BER) curves for the considered approaches QC and CS.

Resumo-Este trabalho aborda os aspectos de processamento estatístico de sinais e teoria da informação para supressão (cancelamento) de interferência em sistemas com múltiplas entradas e múltiplas saídas (MIMO, do inglês multiple input multiple output) e aspectos de modelagem considerando aspectos geométricos nos sistemas de recuperação da informação. As ferramentas das quais lançamos mão neste trabalho permitem uma aplicação em um grande número de sistemas de informação, não só no problema clássico de comunicações digitais, tais como processamento de voz, imagens, além deáreas por vezes menos conhecidas da comunidade de processamento de sinais, como por exemplo sensoriamento remoto e desconvolução sísmica.