Joint time domain nonlinear post-distortion scheme for reconstruction of distorted signals

Abstract

Reconstruction of distorted signals (RODS), initially proposed in the frequency domain (FD), has been proved to be with high efficiency in depressing the distortion caused by the nonlinear power amplifier (PA). However, multiple high-dimensional transformation matrices are needed to reconstruct the FD distortion matrix, so high complexity is required. In this paper, we propose a new unified time domain (TD) nonlinear post-distortion scheme based on RODS, where a joint distortion matrix containing both PA and multipath channel coefficients is presented. When carrying out the least square inverse operation, the nonlinearity as well as channel fading effect can be eliminated simultaneously. By adjusting the elements in the distortion matrix according to the characteristics of PA and multipath channels, the proposed TD-RODS can also be suitable for flat fading with memoryless or memory nonlinear PAs. Further, the equivalence between the TD- and FD-RODS is presented, and then computer simulations are adopted to verify our analysis. In the proposed TD-RODS, the nonlinear distortion matrix is constructed more straightforward in a more cost-efficiency way, thus the overall computations is effectively reduced.