XXXI Simpósio Brasileiro de Telecomunicações

This paper presents a binary matrix code based on QR Code (Quick Response Code), denoted as CQR Code (Colored Quick Response Code), and evaluates the effect of JPEG and JPEG2000 compression on the decoding process. The proposed CQR Code has three additional colors (red, green and blue), what enables twice as much storage capacity when compared to the...

High order modulation nonlinear effects has been appointed as the main limitation in coherent optical fiber transmission. Many different approaches has been investigated to cope with nonlinear effects in optical systems and the most studied method for coherent systems is the digital back-propagation algorithm. MLSE methods have also been effective in...

This work considers the uplink of a multiuser heterogeneous cellular network based on direct-sequence code division multiple access (DS-CDMA). Two cases are considered: i) a centralized case, where a base-station (BS) gathers the information of all users; and ii) a distributed case, where micro-BS nodes perform the signal processing in a distributed...

The objective of this work is to perform real-time full HD video encoding by using the x264 library. This library implements in software a high performance H.264/AVC encoder whose set of configuration parameters contains a large number of options. Thus, a methodology is proposed in order to select a relevant subset of parameters which allow real-time...

Seismic imaging is a tool to reconstruct the sub-structure of a given ground from the data collected in a seismic acquisition. The standard technique for this purpose is called migration. This technique has resolution, i.e., the capacity to differentiate two nearby elements, limited by factors such as the size of the acquisition coverage and the...

This paper proposes an improved and more general model for the η-μ fading distribution. The rationale behind this new model lies in the introduction of a phase parameter affecting the balance of number of multipath clusters in phase and quadrature signals. Despite the introduction of the phase parameter, the obtained formulations are still presented in...

Four strategies for LDPC code shortening has been investigated in this work. A shortening strategy is characterized basically by the choice of positions in the information-word to place the known shortening bits. Our simulation results have shown that the right choice of the shortening strategy is an important issue. Of the examined strategies the one...

This article presents an algorithm to estimate a distributed target’s azimuth using an ArcSAR radar. This radar has transmitting and receiving antennas which rotate around a fixed axis with constant angular velocity, aiming a high nominal resolution in azimuth. In this scenario, this radar has two transmitting and receiving channels and uses this...

This paper presents two transmission schemes for MIMO systems considering the use of a precoding at the transmitter. The precoders are updated at each new transmission frame and this updating is based on the feedback information. One transmission scheme uses the precoder for rotating the transmitted symbol phase, while the other one considers the...

In this paper, the cubic interpolation process is analyzed. We use information about the acquisition process of the sequence to be interpolated to set the cubic interpolation filter. This analysis provides relationships between the filter parameter a and the autocorrelation function of the sequence to be interpolated which minimize the MSE for many...