Performance of MF-MSK Systems with Pre-distortion Schemes

TL;DR

This paper presents a predistortion technique to enhance the linearity of Traveling Wave Tube Amplifiers (TWTAs) in RF communication systems, enabling performance comparable to or better than solid-state amplifiers.

Contribution

It introduces a predistorter scheme based on Saleh's model extension to improve TWTA linearity for MF-MSK signals in nonlinear channels.

Findings

Predistortion significantly improves TWTA linearity.

Enhanced TWTA performance can match or surpass SSPA.

Analysis confirms effectiveness for MF-MSK in nonlinear channels.

Abstract

Efficient RF power amplifiers used in third generation systems require linearization in order to reduce adjacent channel inter-modulation distortion, without sacrificing efficiency. Digital baseband predistortion is a highly cost-effective way to linearize power amplifiers (PAs). New communications services have created a demand for highly linear high power amplifiers (HPA's). Traveling Wave Tubes Amplifiers (TWTA) continue to offer the best microwave HPA performance in terms of power efficiency, size and cost, but lag behind Solid State Power Amplifiers (SSAP's) in linearity. This paper presents a technique for improving TWTA linearity. The use of predistorter (PD) linearization technique is described to provide TWTA performance comparable or superior to conventional SSPA's. The characteristics of the PD scheme is derived based on the extension of Saleh's model for HPA. The analysis results of Multi-frequency Minimum Shift Keying (MF-MSK) in non-linear channels are presented in this paper.