Joint adaptive bias point adjustment and digital pre-distortion for power amplifier

摘要

One embodiment of the present invention relates to a method and apparatus are provided herein for reducing the power consumption of a transmission chain while maintaining an acceptable figure of merit (e.g., linearity). In one embodiment, an adaptive biasing element is configured to perform adaptive biasing to reduce current consumption of a transmission chain by adjusting the operating point of one or more transmission chain elements (e.g., power amplifier, mixer, etc.). However, since adaptive biasing may reduce the linearity of a transmitted signal, its use is limited by the degradation of figure of merit caused by the introduced non-linearities. Accordingly, a pre-distortion element may be configured to perform adaptive digital pre-distortion (DPD) on a transmission chain input signal to account for non-linearities generated through the adaptive biasing, therefore allowing the adaptive biasing to further reduce the current consumption while maintaining an acceptable figure of merit.

主权项

1. A transmitter circuit, comprising:
one or more transmission chain elements configured to receive an input signal and to generate an output signal; a figure of merit measurement element configured to receive information about the output signal from a feedback loop, extending from the one or more transmission chain elements to the figure of merit measurement element, and to determine a measured figure of merit of the output signal; an adaptive biasing element configured to adaptively bias the one or more transmission chain elements to iteratively reduce a current consumption of the one or more transmission chain elements until the measured figure of merit violates a predetermined quality standard; and a pre-distortion element located upstream of the one or more transmission chain elements and configured to generate a distorted input signal to improve the measured figure of merit and thus account for non-linearities introduced into the output signal during the adaptive biasing, until the measured figure of merit no longer violates the predetermined quality standard.