Browse Prior Art Database

Equalization of Non-Linear Channels

IP.com Disclosure Number: IPCOM000017128D
Publication Date: 2003-Jul-22
Document File: 5 page(s) / 153K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that introduces a new equalizer structure to digitally post compensate non-linear Inter-Symbol Interference (ISI). Benefits include the ability to equalize channels that suffer from both non-linear distortion and linear dispersion.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

 

Equalization of Non-Linear Channels

Disclosed is a method that introduces a new equalizer structure to digitally post compensate non-linear Inter-Symbol Interference � (ISI). Benefits include the ability to equalize channels that suffer from both non-linear distortion and linear dispersion.

Background

Non-linear ISI cannot be optimally compensated with conventional Feed Forward Equalizers (FFE’s) or Decision Feedback Equalizers (DFE’s).� These conventional equalizers were intended to compensate for linear ISI only.

Often data, x, transmitted through a non-ideal channel is received as a corrupted signal, y, and is unrecoverable without equalization. Thus receiver designers often use a Linear Feed Forward Equalizer that consists of a linear Finite Impulse Response (FIR) filter for a Feed Forward Filter (FFF). See Figure 1. To initialize this filter, one must find a set of coefficients, wf, which Minimizes the Mean Square Error (MMSE) between the equalized and transmitted waveform.�

To implement this equalizer, the coefficients, wff, are applied to a FIR filter (see Figure 2). Figure 2 assumes a three tap FIR filter functions as the FFF shown in Figure 1.

On other occasions, receiver designers use a DFE that consists of a two linear FIR filters – one for a FFF and one for a Feed Back Filter (FBF). See Figure 3. To initialize this filter, one must find a set of coefficients, w, which minimizes the MSE between the equalized and transmitted waveform. The coefficients wff are applied to a FIR filter in the location of the FFF and the coefficients wfb are applied to a FIR filter in the location of the FBF shown in Figure 3.

General Description

The disclosed method uses Volterra non-linear f...