A Simplicial Canonical Piecewise Linear Adaptive Filter

Abstract

A new adaptive nonlinear filter realization is presented based on a canonical piecewise linear (CPWL) approach. This filter realization consists of a linear part represented by a finite impulse response filter and a zero-memory nonlinear part implemented as a CPWL map. The resultant structure requires fewer parameters than other realizations found in the literature with comparable modeling capabilities. As a consequence, the proposed nonlinear filter, in addition to its simple description, has low computation and implementation costs. Some results related to convergence properties and implementation of the adaptive algorithm associated to this new realization are presented. The performance of the proposed filter is illustrated through simulation examples.

Compensation for Nonlinear Distortion in OFDM Systems Using a Digital Predistorter Based on the SCPWL Model

“…The parameters β i divide the domain in equal partitions, with β 1 ≤ β 2 ≤ · · · ≤ β σ . From (5) it is clear that the nonlinear gain implicitly includes a saturation behavior. The structure of the SCPWL model considered in this study is shown in Fig.…”

“…In this paper, we propose a simplicial canonical piecewiselinear (SCPWL) model [4], [5] based DPD to compensate for nonlinear distortion introduced by a HPA in OFDM systems. The simiar study has been reported in [6], in which the same SCPWL function was employed but only the normalized amplitude modulation to amplitude modulation (AM/AM) response was considered.…”

A special complex-valued simplicial canonical piecewise linear function for amplifier and predistorter nonlinearity representation

“…The conventional SCPWL function in [4] only fits for R 1 domain and allows the representation of any arbitrary continuous nonlinearity between two real-valued variables. Thus, the polar structure becomes the inevitable choice for baseband complex-valued signal modeling, especially in the digital predistortion system.…”

Spectral characteristics of a piecewise linear function in modeling power amplifier type nonlinearities

“…Recently, a piecewise linear function known as the simplicial canonical piecewise linear (SCPWL) function [8] has been proposed for modeling PA and PD characteristics [9], [10]. The order of the SCPWL function in terms of IMD products cannot be directly observed in its transfer function, as can be done for a polynomial model.…”