System for pre-distorting an input signal for a power amplifier using-non-orthogonal coordinates

US6630862B1 · kind B1 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Rainer Perthold · Weisendorf, DE
• Gerald Ulbricht · Westerburg, DE
• Heinz Gerhaeuser · Erlangen, DE

Key dates

• Filing date: Aug 29, 2001
• Grant date: Oct 7, 2003
• Expiry date: Aug 29, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03F1/3241
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

A circuit for pre-distorting an input signal v to be transmitted via a power amplifier having a non-linear transmission characteristic to produce a pre-distorted input signal y comprises an estimator (10) for determining an estimation signal (22) based on the power of said input signal v. A look-up table (20) is provided for storing complex pre-distortion coefficients BR and AI which depend on the power of the input Signal v and the non-linear transmission characteristic of the power amplifier determined in advance. For BR, the relation BR=AR&#8722;K, K being a constant with 0<K <2 applies, and AR and AI are the real and imaginary parts of a complex pre-distortion function which provides a pre-distortion of the input signal v such that the distortion introduced by the non-linear transmission characteristic of the power amplifier is substantially compensated according to magnitude and phase. Finally, a pre-distorter is provided in order to pre-distort the input signal according to y=v&middot;(K+BR+jAI).