XXXI Simpósio Brasileiro de Telecomunicações

Given a set of spectrum partials obtained from shorter windowed signal frames, it is proposed a fundamental frequency estimation by calculating the approximate GCD of such partials and applying a weighted K-means cluster method to classify them. Such an algorithm allows the use of shorter frame sizes, resulting in high temporal resolution for the...

The transmission of real-time multimedia streams requires service guarantees, such as limited packet loss, minimum bandwidth and limited delay and jitter, in order to deliver a good quality of experience (QoE) for viewers. The spatial and temporal redundancy of videos is explored by coding algorithms, reducing the amount of information necessary to...

In this paper, we compare the energy efficiency of different multiple antenna (MIMO) techniques in wireless sensor networks. The considered energy consumption model takes into account the radio frequency (RF) circuitry, the efficiency of the power amplifier, and the transmission rate. Since the energy consumption of the additional RF chains...

Several spatial filters applied to images are available in technical and scientific literature. Besides the reduction of the noise level, some of them also aim at the preservation of the edges as well as the details. Those filters are commonly applied to the processing of X-ray medical image sequences, which are usually noised due to the low doses...

Communication channels with Rayleigh flat fading are modeled in this work using a class of finite-state Markovian channels denoted by birth and death channels. Modeling results reveal a good agreement between the two channels for a wide range of fading conditions.

We introduce a new concept called zero-error accessible information of a quantum source which measures the amount of information shared by two parties, one which has a quantum source, and the other which uses a measurement scheme to decode the quantum states received, upon the restriction that no decoding errors must occur. No general method to...

In this contribution, lattice reduction (LR) technique is applied to improve the MIMO detector performance under correlated channel constrains. Zero-forcing, minimum mean squared error (MMSE), ordered successive interference cancellation (OSIC) and sphere decoding (SD) detectors are analysed taking into consideration a) different correlated...

In this work, low-complexity suboptimum detectors have been analyzed for a single-input multiple-output (SIMO) direct-sequence code division multiple access (DS/CDMA) system. As a contribution, a hybrid multiuser detector based on polynomial expansion (PE-MuD) with alpha-estimation determined by Gerschgorin circles Theorem (GCT), and followed by a...

This paper aims to analyse the performance of spatial modulation (SM) techniques under imperfect channel state information (iCSI), i.e., errors in the estimation of channel coefficients. The results are compared with the classic spatial multiplexing technique V-BLAST. Furthermore, computational complexity for both SM and V-BLAST are evaluated in...

In this paper, assuming a spectrum sharing environment, we investigate the performance of a full-duplex dualhop cooperative cognitive network composed by one secondary source, one secondary relay, and one secondary destination, where this latter applies joint decoding with the signals received from the source and relay such that the direct link can...