Reducing the Intermodulation Distortion in Ofdm Systems by Feedforward Linearization Technique

Abstract

This study presents a feedforward linearizer, in order to reduce the intermodulation distortion (IMD) caused by the nonlinear properties of the radio frequency (RF) power amplifier (PA) in orthogonal frequency-division multiplexing (OFDM) systems. The design procedure and validation of OFDM system and feedforward linearizer have been carried out by Agilent-ADS. In order to evaluate the performance of the feedforward linearizer, sweeping back-off power has been used. Adjacent channel power ratio (ACPR) levels versus back-off power results are investigated to evaluate the performance of the linearization technique. Efficiency improvement is figured out by investigating the power added efficiency (PAE) versus back-off power. Simulation results have been shown that ACPR improvements were acceptable for OFDM system when the PA is utilized together with feedforward linearizer. © 2009 IEEE.