Digital pre-distortion technique using nonlinear filters

摘要

A system and method for stabilizing a coefficient set used by a digital predistortion (DPD) engine to apply pre-distortion to a transmit signal and cancel distortion generated by a distorting element or distorting system when transmitting the transmit signal, including obtaining an initial coefficient set; rotating the initial coefficient set to maintain a phase of fundamental components (w₁₀(t), . . . , w_1Q(t)) of the initial coefficient set as a constant value; averaging in the time domain the rotated coefficient set to obtain an averaged coefficient set; applying the averaged coefficient set to the DPD engine, the initial coefficient set expressed in a first equation [27]; computing the phase of the fundamental components of the initial coefficient set with a second equation [28]; and computing the rotated coefficient set with a third equation [29].