Compensation for Power Amplifier Nonlinearity in the Presence of Local Oscillator Coupling Effects

We consider the design of a digital predistortion (DPD) scheme when there is a crosstalk between a local oscillator (LO) and a power amplifier (PA) called LO self-coupling. We first develop a baseband equivalent model for a direct conversion transmitter afflicted by LO self-coupling. Based on this model, a two-stage process, consisting of a feedback equalizer (FBEQ) and DPD, is proposed for the joint compensation of PA nonlinearity and LO self-coupling. The advantage of the proposed DPD over conventional DPD is demonstrated through computer simulation.