XXXI Simpósio Brasileiro de Telecomunicações

In this paper we propose a low-complexity rate-one multiple-input multiple-output (MIMO) scheme with fourtransmit antennas. A preprocessor design based on phasefeedback information enables the proposed scheme to achievefull diversity order as well as a coding advantage. A signal-to-noise ratio (SNR) analysis is performed and it is used to findthe optimal...

A simple physical model consisting of a point sourcedisplaced from its center of rotation, in combination with adirectivity model that includes backwards emitted energy areconsidered for the problem of estimating the orientation of adirectional acoustic source. We show, however, that when thetime difference of arrival is also taken into account, a...

This work analyzes, through computer simulations,coded cooperative communication systems with a single relayand using the amplify-and-forward (AF) protocol. Nonbinarylow-density parity-check (LDPC) codes are assumed to be used atthe source and a fast Fourier transform (FFT)-based decodingalgorithm is employed at the destination. The performance ofa...

n the last years, there has been an upsurge ofresearch interest in cooperative wireless communications. Thisarticle presents an overview about important topics related withthe promised theoretical gains of cooperative communicationsand their results in real environments. This work does not intendto be exhaustive but can serve as a roadmap to the most...

This paper evaluates, through computer simulations, a coded watermarking system in the discrete wavelet transform (DWT) domain. The robustness of the systemis analyzed in terms of the length of Reed-Solomon (RS)codes and the decoding algorithms adopted. Two scenarios are investigated: transmission of the watermarked image by an additive...

This paper investigates, in a preliminary way, the behavior of the efficiency of binary Huffman codes applied to memoryless sources with three symbols in its alphabet and its extensions. It was observed that, similarly to the case where source and code alphabets have the same cardinality, there is not always gain in efficiency of the Huffman coding by...

This paper proposes a new model for impulsive noise composed by the sum of a Gaussian component modulated by a discrete process C(t), ηi(t)C(t), applied to characterize the noisy impulsive nature, and a permanent component ηg(t). The modulating processes C(t) characterizes the random nature of ηi(t) in time, in other words C(t) is a process which has...

This work aims at discussing a measurement campaign carried out in a residential apartment to measure hybrid PLC-wireless channel. The hybrid PLC-wireless channels is the one that allow portable devices and devices physically connected to electric distribution grids to communicate with each other. Also, it is presented a capacitive coupling device...

This paper proposes an adaptive spatial filter scheme in time-domain (pre-FFT), aimed to improve the performance and the capacity of OFDM systems. This strategy uses a supervised adaptive algorithm, with frequency domain multiplexed pilots of the OFDM system as reference. The simplicity of the proposed structure, as well as the method used to obtain...

This paper presents a tensorial approach for the modeling and estimation of parameters in L-shape vector antenna arrays. Making use of the PARAFAC decomposition, we propose a method for estimating the directions of arrival and polarizations of the sources. The proposed method is based on the combinationof two PARAFAC models that globally characterize the...