Joint Adaptive Bias Point Adjustment and Digital Pre-Distortion for Power Amplifier
First Claim
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 adjusting a current consumption of the one or more transmission chain elements; and
a pre-distortion element located upstream of the one or more transmission chain elements and configured to generate a distorted input signal to account for non-linearities introduced into the output signal during the adaptive biasing.
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Abstract
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.
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Citations
20 Claims
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1. A transmitter circuit, comprising:
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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 adjusting a current consumption of the one or more transmission chain elements; and a pre-distortion element located upstream of the one or more transmission chain elements and configured to generate a distorted input signal to account for non-linearities introduced into the output signal during the adaptive biasing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for reducing a current consumption of a transmission circuit, comprising:
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adaptively biasing one or more transmission chain elements to reduce the current consumption of the one or more transmission chain elements, wherein adaptively biasing the one or more transmission chain elements produces non-linearities in an output signal; evaluating the non-linearities based upon a feedback signal comprising information about the output signal; and generating a distorted input signal, input to the one or more transmission chain elements, having distortions to account for non-linearities caused by adaptively biasing the one or more transmission chain elements. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for reducing a current consumption of one or more transmission chain elements, comprising:
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setting initial bias conditions of one or more transmission chain elements high enough to guarantee good linearity for an output signal and one or more initial pre-distortion coefficients so as to not distort an input signal. determining a measured figure of merit of the output signal; and alternatively or concurrently performing adaptive biasing and updating the pre-distortion coefficients in a stepwise iterative process based on the measured figure of merit. - View Dependent Claims (17, 18, 19, 20)
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Specification