2002 International Telecommunications Symposium

"The conventional QR Decomposition (QRD) method requires order N^2—O[N^2]— multiplications per output samples. However a number of fast QRD algorithms have been proposed with O[N] of complexity. Particularly the Fast QRD algorithm based on a posteriori backward prediction errors is well known for its good numerical behavior and low complexity. This...

"This paper compares the transients of the constrained RLS (CRLS) algorithm with the generalized sidelobe canceller (GSC) employing an RLS algorithm. It is shown that the requirement for transient-equivalence is satisfied by the GSC structure using proper initialization, and any restriction concerning orthogonality of the matrices involved may be...

"The first objective of this work is to analyze the suitability of a framework based on the use of genetic algorithms (GAs) to optimize blind equalization cost functions. This effort is motivated by advances in the field of GAs, as well as by recent breakthroughs in the study of blind techniques and their relations to the Wiener criterion. The second...

"In this work, we propose an approach to the analysis of adaptive filtering criteria, based on an original formulation via least squares. This proposal, though based on some model considerations, possesses great generality and simplicity, encompassing many filtering structures and criteria. The approach is used on the study of three blind techniques...

"A method to code images by approximating them by a triangular mesh is presented. The coder encodes only the amplitudes of mesh nodes (triangle vertices) and the directions and shapes of mesh triangles. The decoder obtains the pixel amplitudes by interpolating the vertex amplitudes of the triangles they belong to. Since the used mesh is regular, the...

"This work reviews the blind linear prediction (LP) approach to combat the loss of digital communications system performance due to intersymbol interference (ISI) and discusses that its alleged robustness to model order overestimation is restricted to the theoretical conditions of exactly known received signal statistics. To circumvent these limitations,...

"This work presents a new fast computational algorithm for decomposing a square signal symmetrical matrix, based on the Jacobi method. It is applied to real time systems with data acquisition updated almost sample by sample. The fast computational technique first involves the Data Matrix formation stage, so as to obtain the desired updated data matrix...

"Finite field transforms have many applications and, in many cases, can be implemented with a low computational complexity. In this paper, the Z Transform over a finite field is introduced and some of its properties are presented."

"The problem of shortening the effective channel impulse response in xDSL is addressed. A new approach is described based on linear phase FIR equaliser filters. The mathematical framework for the LPIRS method is developed and simulation results are presented for several VDSL loops. For a similar performance, the new method offers a design with...

"A blind criterion for adaptive equalization based on probability density function (pdf) estimation is proposed. The criterion measures the divergence between the pdf of an ideally equalized signal and the one from a parametric model resulting in a cost function that is a sort of entropy minimization of the equalizer output signal. It is also shown a...