1. A method comprising: receiving an input polar transmit signal including an input amplitude signal and an input phase signal; generating a predistorted polar transmit signal by predistorting the input polar transmit signal using at least one predistortion parameter selected from a lookup table; generating a phase-and-amplitude modulated radio-frequency transmit signal corresponding to the predistorted polar signal; providing a copy of the generated radio-frequency signal to a polar receiver having an injection lock oscillator (ILO); operating the ILO of the polar receiver to generate in response to the copied, generated radio-frequency signal, a sampled polar signal including a sampled amplitude signal and a sampled phase signal; comparing the sampled polar signal to the input polar transmit signal; and updating the lookup table in response to the comparison.