Mobile wireless communications device with separate in-phase (I) and quadrature (Q) phase power amplification and power amplifier pre-distortion and IQ balance compensation

A mobile wireless communications device comprising:

• a housing;
• an antenna carried by the housing;
• at least one circuit board carried by the housing and including radio frequency (RF) circuitry carried by the at least one circuit board and comprising
• an In-phase (I) circuit comprising an I power amplifier circuit and said I circuit configured to modulate and amplify a digital, baseband I signal,
• a Quadrature (Q) circuit comprising a Q power amplifier circuit and said Q circuit configured to modulate and amplify a digital, baseband Q signal,
• a power combiner configured to receive the separately modulated and amplified I and Q signals and output a combined I and Q signal,
• an I demodulator circuit that directly receives a feedback signal from the I power amplifier circuit and configured to demodulate the feedback signal from the I power amplifier circuit and produce a demodulated I signal,
• a Q demodulator circuit that receives a feedback signal from the Q power amplifier circuit and configured to demodulate the feedback signal from the Q power amplifier circuit and produce a demodulated Q signal, and
• a processor configured to compare the digital, baseband I and Q signals with the demodulated I and Q signals to compensate for at least one of an amplitude error, a frequency error, and a phase modulation error.

A method of operating a communications device comprising:

• modulating and amplifying within an I power amplifier circuit a digital, baseband In-phase (I) signal using an I circuit;
• modulating and amplifying with a Q power amplifier circuit a digital, baseband Quadrature (Q) signal using a Q circuit
• outputting a combined I and Q signal using a power combiner receiving the separately modulated and amplified I and Q signals;
• receiving a feedback signal directly from the I power amplifier circuit and demodulating the feedback signal from the I circuit using an I demodulator to produce a demodulated I signal;
• receiving a feedback signal from the Q power amplifier circuit and demodulating the feedback signal from the Q circuit using a Q demodulator to produce a demodulated Q signal;
• and
• comparing the digital, baseband I and Q signals with the demodulated I and Q signals using a processor to compensate for at least one of an amplitude error, a frequency error, and a phase modulation error.