System and method for digital predistortion

An antenna unit comprising:

• a digital pre-distortion engine configured to receive a modulated digital data signal from a physically separate radio unit located remote from the antenna unit, the digital pre-distortion engine further configured to pre-distort the modulated digital data signal;
• a digital to analog converter configured to convert the pre-distorted digital data signal to a pre-distorted analog data signal;
• and
• a power amplifier configured to amplify the pre-distorted analog data signal, wherein the power amplifier distorts the pre-distorted analog data signal, the distortion introduced by the power amplifier being opposite to the pre-distortion introduced by the digital pre-distortion engine such that the pre-distortion introduced by the digital pre-distortion engine approximately cancels the distortion introduced by the power amplifier;
• wherein the digital pre-distortion engine is configured to pre-distort the modulated digital data signal based on coefficients calculated by a coefficient computation engine in the radio unit.

A method of compensating for distortion introduced by a power amplifier, the method comprising:

• computing a plurality of coefficients for a pre-distortion operation in a radio unit;
• providing the computed coefficients from the radio unit to an antenna unit, the antenna unit being physically separate from the radio unit and located remote from the radio unit;
• pre-distorting a digital data signal in the antenna unit based on the computed coefficients received from the radio unit, the digital data signal received in the antenna unit from the radio unit;
• converting the pre-distorted digital data signal in the antenna unit to an analog pre-distorted data signal;
• and
• amplifying the analog pre-distorted data signal with the power amplifier in the antenna unit, wherein amplifying the analog pre-distorted data signal introduces distortion into the amplified analog pre-distorted data signal;
• wherein the coefficients used in applying the pre-distortion are computed in the radio unit such that the pre-distortion is approximately equal and opposite to the distortion introduced by the power amplifier such that the pre-distortion approximately cancels the distortion introduced by the power amplifier.