Embodiments described herein relate to methods and apparatuses for performing digital
predistortion, DPD, to provide a transmit
signal, x̆(n) wherein the transmit
signal, x̆(n), is for deriving one or more
amplifier signals, x̆m(n), for driving one or more power amplifiers, wherein the one or more power amplifiers are associated with a respective one or more antenna elements. A method comprises: receiving a first
signal, x(n); inputting the first signal, x(n), into a combination model, wherein the combination model comprises a
machine learning, ML, model and a
memory polynomial, MP, model; and outputting the transmit signal x̆(n), from the combination model.