TCM schemes with predistortion techniques on nonlinear channels

Abstract

The performance of predistorted trellis-coded modulation (TCM) schemes operating over a compensated nonlinear channel is discussed. Compensation methods are chosen in such a way that constellation warping is balanced and intersymbol interference is reduced. This is done by using an adaptive process that includes the effects of the system memory in the computation of predistorted points. Using optimal TCM schemes for a linear channel it is shown that the same coding gains can be achieved on a compensated nonlinear channel and on a linear channel when the 16-QAM (quadrature amplitude modulation) signal constellation is used. The focus is on the comparison of the results obtained for different codes and several predistortion methods in such a way so that the attainable performance can be studied.