XXX Simpósio Brasileiro de Telecomunicações

This paper discusses the network dimensioning strategies of two operating companies that supply channels to the same population of users based on a common infrastructure, in a competitive environment. The users wish to be serviced with minimum blocking probability, while the operators wish to maximize their profits. The resulting two...

Since Gallager introduced Bit-Flipping (BF ) deco- ding with hard-decision for Low-Density Parity-Check Codes (LDP C), other two variants were proposed by Sipser and Spielman for expander codes. Later, a soft-decision version of BF decoding, known as Modified Weighted BF (M W BF ) decoding, was investigated. This article proposes modified versions...

High resolution algorithms such as SAGE (Space Alternating Generalized Expectation Maximization) may be used to obtain the time response from a communication channel and, consequently, to obtain the power delay profile from environment. This paper presents a measure campaign by frequency sounding which employs SAGE to process these measurements,...

This paper studies the problem of depth map compression for 3D video applications, based on virtual view synthesis. In this context, we propose an alternative algorithm to the current image coding standards, which avoids the known problems of depth map compression. The proposed algorithm is based on a flexible segmentation, combined with an...

There are numerous methods to increase pixel density in an image, many of them based in its frequency com- ponents, others based in computational intelligence techniques, among others. In this paper, we implement a supersampling method based on ISAT (In Situ Adaptive Tabulation). To assess the method’s efficiency, we compare the results of our...

In this paper, we investigate the ergodic capacity of multiple-input multiple-output (MIMO) wireless communication systems over spatially uncorrelated Rayleigh-fading channels, assuming that the channel state information (CSI) is unknown at the transmitter and perfectly known at the receiver. Applying some results of majorization theory, we provide...

Recently, considerable attention has been given to the problem of robust detection and tracking of facial features. In this work, a framework for facial landmarks detection is presented. This framework is comprised by three interchangeable parts, namely preprocessing, classification and post-processing. In the classification stage, we used a cascade...

This work proposes three different ways to apply the Kahunen and Loève Transform (KLT) in the algorithm for image compression recommended by CCSDS, in order to reduce the interband redundancy of multispectral images. The proposed schemes work with a fixed rate and have a simple algorithm to allocate the rate over the KLT components. The new...

This paper evaluates the outage performance of multiuser relay networks in which the source and each one of the destinations are equipped with multiple antennas and employ beamforming techniques. More specifically, assuming Rayleigh fading channels and an amplify-and-forward relay, a general closed-form expression for the end-to-end outage...

In this paper, we present a definition for the fractio- nal cosine transform over finite fields. The proposed transform is derived from the knowledge of the eigenstructure of the discrete cosine transform and its relations with the eigenstructure of the discrete Fourier transform. A possible application of the new transform in the field of image...