Nonlinear Neural Network with Phase Normalization for Base-Band Modelling of Radio-Frequency Non-Linearities

An apparatus, comprising:

• at least one processor;
• and
• at least one non-transitory memory storing instructions that, when executed with the at least one processor, cause the apparatus to perform:
• obtaining a data communication signal comprising a plurality of complex-valued input samples;
• capturing, from the plurality of complex-valued input samples, a current sample and a set of delayed samples;
• generating a phase-normalized input signal based on normalizing phase of the current sample and the set of delayed samples with a normalization term, wherein the normalization term is common for the current sample and the set of delayed samples;
• providing the phase-normalized input signal to a neural network configured to mitigate non-linearity of a data communication chain and to output a complex-valued output sample for the plurality of complex-valued input samples;
• and
• denormalizing phase of the complex-valued output sample with a denormalization term configured to restore phase of the data communication signal;
• wherein the normalization is based on multiplication of the current sample and the delayed samples with the normalization term, and wherein the denormalization is based on multiplication of the complex-valued output sample with the denormalization term, wherein the denormalization term comprises a complex conjugate of the normalization term.