Digital predistortion tailored to specified frequencies in the power amplifier (PA) output spectrum

Patent metadata

Field	Value
Publication number	US-10097141-B1
Application number	US-201715615192-A
Country	US
Kind code	B1
Filing date	Jun 6, 2017
Priority date	Jun 6, 2017
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

An apparatus to apply frequency selective digital predistortion (DPD) to a power amplifier (PA) circuit is disclosed. The apparatus comprises a first transformation circuit configured to receive a PA input comprising a quantity indicative of an input signal of the PA circuit and process the PA input by applying a first predetermined weighted function, to form a processed PA input, and a second transformation circuit configured to receive a PA output comprising a quantity indicative of an output signal of the PA circuit and process the PA output by applying a second predetermined weighted function, to form a processed PA output. The apparatus further comprises a coefficient computation circuit configured to receive the processed PA input and the processed PA output; and estimate distortion coefficients, to be utilized for predistorting the input signal of the PA circuit, based on the processed PA input and the processed PA output.

First claim

What is claimed is:

1. An apparatus that facilitates to apply frequency selective digital predistortion (DPD) to a power amplifier (PA) circuit, comprises:
a first transformation circuit configured to receive a PA input comprising a processed version of an input signal of the PA circuit and process the PA input based on a first predetermined weighted function, to form a processed PA input;
a second transformation circuit configured to receive a PA output comprising a processed version of an output signal of the PA circuit and process the PA output based on a second predetermined weighted function, to form a processed PA output; and
a coefficient computation circuit configured to:
receive the processed PA input and the processed PA output; and
estimate distortion coefficients, to be utilized for predistorting the input signal of the PA circuit, based on the processed PA input and the processed PA output.

2. The apparatus of claim 1 , wherein the first predetermined weighted function and the second predetermined weighted function facilitates to apply specific weights to specified frequencies in an output spectrum of the PA circuit.

3. The apparatus of claim 1 , wherein the distortion coefficients comprises inverse PA coefficients associated with the PA circuit, estimated based on a predetermined relation between the processed PA output and the processed PA input, wherein the predetermined relation is derived in accordance with a predetermined inverse memory model of the PA circuit.

4. The apparatus of claim 3 , wherein the PA input comprises a PA input vector comprising a plurality of PA input samples associated with the input signal of the PA circuit and the PA output comprises a PA output matrix constructed from output measurements of the PA circuit, wherein the PA output matrix is constructed based on the predetermined inverse memory model associated with the PA circuit.

5. The apparatus of claim 1 , wherein the distortion coefficients comprises PA coefficients associated with the PA circuit, estimated based on a predetermined relation between the processed PA output and the processed PA input, wherein the predetermined relation is derived in accordance with a predetermined memory model of the PA circuit.

6. The apparatus of claim 5 , wherein the PA input comprises a PA input matrix constructed from input measurements associated with the input signal of the PA circuit, wherein the PA input matrix is constructed based on the predetermined memory model associated with the PA circuit, and the PA output comprises an PA output vector comprising a plurality of PA output samples.

7. The apparatus of claim 1 , wherein the coefficient computation circuit is further configured to provide the predistortion coefficients to a predistortion circuit associated with the PA circuit, in order to predistort the input signal of the PA circuit.

8. The apparatus of claim 1 , wherein the first predetermined weighted function and the second predetermined weighted function are the same.

9. The apparatus of claim 1 , further comprising an input processing circuit configured to receive the input signal of the PA and generate the PA input based thereon.

10. The apparatus of claim 1 , further comprising an output processing circuit configured to receive the output signal of the PA and generate the PA output based thereon.

11. The apparatus of claim 2 , wherein the first predetermined weighted function and the second predetermined weighted function comprises a linear transformation matrix comprising a plurality of filter coefficients that defines a filter, wherein the filter is determined based on frequencies required in the output spectrum of the PA circuit.

12. A power amplifier (PA) system, comprises:
a PA circuit configured to receive a PA input signal and amplify the PA input signal to generate a PA output signal based thereon;
a coefficient estimation circuit, comprising:
a first transformation circuit configured to receive a PA input comprising a processed version of the PA input signal associated with the PA circuit and process the PA input based on a first predetermined weighted function, to form a processed PA input;
a second transformation circuit configured to receive a PA output comprising a processed version of the PA output signal associated with the PA circuit and process the PA output based on a second predetermined weighted function, to form a processed PA output; and
a coefficient computation circuit configured to:
receive the processed PA input and the processed PA output; and
estimate distortion coefficients to be utilized for predistorting the PA input signal, based on the processed PA input and the processed PA output.

13. The system of claim 12 , wherein the first predetermined weighted function and the first predetermined weighted function facilitates to apply specific weights to specified frequencies in an output spectrum of the PA circuit.

14. The system of claim 12 , further comprising a predistortion circuit coupled to the input of the PA circuit and configured to:
receive the distortion coefficients from the coefficient estimation circuit; and
modify the PA input signal, based on the distortion coefficients.

15. The system of claim 12 , wherein the distortion coefficients comprises inverse PA coefficients associated with the PA circuit, estimated based on a predetermined relation between the processed PA output and the processed PA input, wherein the predetermined relation is derived in accordance with a predetermined inverse memory model of the PA circuit.

16. The system of claim 15 , wherein the PA input comprises a PA input vector comprising a plurality of PA input samples associated with the PA input signal and the PA output comprises a PA output matrix constructed from output measurements of the PA output signal associated with the PA circuit, wherein the PA output matrix is constructed based on the predetermined inverse memory model associated with the PA circuit.

17. The system of claim 12 , wherein the distortion coefficients comprises PA coefficients associated with the PA circuit, estimated based on a predetermined relation between the processed PA output and the processed PA input, wherein the predetermined relation is derived in accordance with a predetermined memory model of the PA circuit.

18. The system of claim 17 , wherein the PA input comprises a PA input matrix constructed from input measurements associated with the PA input signal, wherein the PA input matrix is constructed based on the predetermined memory model associated with the PA circuit, and the PA output comprises an PA output vector comprising a plurality of PA output samples associated with the PA output signal.

19. The system of claim 12 , wherein the first predetermined weighted function and the second predetermined weighted function are the same.

20. The system of claim 12 , wherein the coefficient estimation circuit further comprises an output processing circuit configured to receive the PA output signal and generate the PA output based thereon.

21. The system of claim 12 , wherein the coefficient estimation circuit further comprising an input processing circuit configured to receive the PA input signal and generate the PA input based thereon.

22. The system of claim 13 , wherein the first predetermined weighted function and the second predetermined weighted function comprises a linear transformation matrix comprising a plurality of filter coefficients that defines a filter, wherein th

Assignees

• Intel Corp

Inventors

• Almog Itay
• Kerner Michael
• Gazneli Avi

Classifications

• H04L27/367

  using predistortion · CPC title

• H03F2201/3212

  Using a control circuit to adjust amplitude and phase of a signal in a signal path · CPC title

• H04B2001/0425

  with linearisation using predistortion · CPC title

• H04B1/0475 Primary

  with means for limiting noise, interference or distortion (H04B1/0483 takes precedence) · CPC title

• H03F1/3241 Primary

  using predistortion circuits (H03F1/3211, H03F1/3217 take precedence) · CPC title