A data predistortion technique for the compensation of nonlinear distortion in MC-CDMA systems

We present a data predistorter to compensate for nonlinear distortion introduced by a traveling wave tube amplifier employed in multi carrier-code division multiple access (MC-CDMA) system. The proposed predistorter rests upon the fixed point iteration (FPI) associated with the contraction mapping theorem. Unlike the predistorter based on the FPI already proposed by the authors in another study which operates on complex-valued modulated signal, the proposed predistorter in this paper deals with real-valued FPI on signal amplitude, resulting in much less complexity. Simulation results on a 64-subcarrier synchronous MC-CDMA system indicate that the proposed predistorter achieves significant improvement in terms of total degradation over that without the predistorter. Moreover, the proposed predistorter outperforms its complex-valued counterpart, in particular, for small output back-off levels.