Adaptive Pre-Distortion of Nonlinear Systems Using Out-of-Band Energy Minimization

A new adaptive pre-distortion algorithm is presented for nonlinear systems with memory. The algorithm uses the out-of-band signal energy at the output of the nonlinear distortion to estimate the parameters of the pre-distorter. The proposed approach does not employ a direct comparison between the input and output signals of the nonlinear distortion, thereby avoiding potential problems with measurement or down-conversion processes. It is shown to outperform the pth-order inverse that tends to produce significant distortion for large inputs. The effectiveness of the pre-distortion algorithm is illustrated with simulation examples.