Obtaining reliable and specific data for adaptive digital predistortion

Patent metadata

Field	Value
Publication number	US-2022190852-A1
Application number	US-202117537724-A
Country	US
Kind code	A1
Filing date	Nov 30, 2021
Priority date	Dec 10, 2020
Publication date	Jun 16, 2022
Grant date	—

Abstract

Systems, devices, and methods related to performing digital predistortion in radio frequency (RF) systems are provided. A digital predistortion (DPD) arrangement includes a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component. The DPD arrangement further includes a DPD capture circuit to perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component; compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and perform, based on the one or more criteria, the subsequent capture of the feedback signal. The DPD arrangement circuit further includes a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

First claim

1 . A digital predistortion (DPD) arrangement, the DPD arrangement comprising:
a DPD actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of a nonlinear component; a DPD capture circuit to:
perform, based on a capture cycle timing, multiple captures of a feedback signal, the feedback signal indicative of an output of the nonlinear component;
compute, based on one or more characteristics of the multiple captures, one or more criteria for a subsequent capture of the feedback signal; and
perform, based on the one or more criteria, the subsequent capture of the feedback signal; and
a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent capture.

2 . The DPD arrange of claim 1 , wherein the DPD capture circuit further computes the one or more characteristics for the multiple captures.

3 . The DPD arrangement of claim 1 , wherein the one or more characteristics of the multiple captures comprises a statistical measure associated with at least one of a peak power or a mean power.

4 . The DPD arrangement of claim 3 , wherein the DPD capture circuit further stores, at a memory, the statistical measure associated with the at least one of the peak power or the mean power.

5 . The DPD arrangement of claim 1 , wherein the DPD capture circuit computes the one or more criteria by setting one or more thresholds for the subsequent capture based on the one or more characteristic for the multiple captures.

6 . The DPD arrangement of claim 5 , wherein the one or more thresholds for the subsequent capture comprises at least one of:
an upper bound threshold peak power; a lower bound threshold peak power; an upper bound threshold mean power; a lower bound threshold mean power; an upper bound threshold number of samples exceeding a first threshold; or a lower bound threshold number of samples exceeding a second threshold.

7 . The DPD arrangement of claim 1 , wherein the DPD capture circuit performs the subsequent capture based on the one or more criteria by:
monitoring the feedback signal until a portion of the feedback signal satisfies the one or more criteria.

8 . The DPD arrangement of claim 7 , wherein the DPD adaptation circuit updates the DPD coefficients further based on the portion of the feedback signal that satisfies the one or more criteria.

9 . The DPD arrangement of claim 7 , wherein the DPD capture circuit further stops the subsequent capture based on a detection of the portion of the feedback signal satisfying the one or more criteria.

10 . The DPD arrangement of claim 7 , wherein the DPD capture circuit further stores, at a memory, the portion of the feedback signal satisfying the one or more criteria.

11 . A radio frequency (RF) device comprising:
a nonlinear component; a digital predistortion (DPD) actuator circuit to predistort, using DPD coefficients, at least a portion of an input signal, the DPD coefficients associated with a characteristic of the nonlinear component; a DPD capture circuit to:
capture, based on a specified capture cycle timing, multiple bursts of a feedback signal, the feedback signal indicative of an output of the nonlinear component;
compute, based on the multiple bursts, one or more statistical measures for determining one or more thresholds for a subsequent capture; and
perform the subsequent capture by monitoring the feedback signal for a subsequent portion of the feedback signal that satisfies the one or more thresholds; and
a DPD adaptation circuit to update the DPD coefficients based at least in part on the subsequent portion of the feedback signal that satisfies the one or more thresholds.

12 . The RF device of claim 11 , wherein the DPD capture circuit further determines, based on the one or more computed statistical measures of the multiple bursts of the feedback signal, the one or more thresholds for the subsequent capture of the feedback signal.

13 . The RF device of claim 12 , wherein the one or more thresholds for the subsequent capture of the feedback signal comprises at least one of:
an upper bound threshold peak power; a lower bound threshold peak power; an upper bound threshold mean power; a lower bound threshold mean power; an upper bound threshold number of samples exceeding a first threshold; or a lower bound threshold number of samples exceeding a second threshold.

14 . The RF device of claim 12 , wherein the DPD capture circuit comprises:
a capture triggering circuit to trigger, based on the specified capture cycle timing, capturing of the multiple bursts of the feedback signal; and a measurement circuit to compute, based on the multiple bursts, the one or more statistical measures for determining the one or more thresholds for the subsequent capture.

15 . A method for performing digital predistortion (DPD), the method comprising:
predistorting, using a DPD actuator circuit, at least a portion of an input signal based on DPD coefficients associated with a characteristic of a nonlinear component; capturing, based on a specified capture cycle timing using a DPD capture circuit, multiple portions of a feedback signal, the feedback signal indicative of an output of the nonlinear component; computing, based on one or more statistical measures of the multiple captured portions of the feedback signal, one or more criteria for a subsequent capture of the feedback signal; performing the subsequent capture based on the one or more criteria, wherein the performing comprises monitoring the feedback signal until a detection of a subsequent portion of the feedback signal satisfies the one or more criteria; and updating, using a DPD adaptation circuit, the DPD coefficients based at least in part on the subsequent portion of the feedback signal.

16 . The method of claim 15 , further comprising:
computing the one or more statistical measures for the multiple portions of the feedback signal, wherein the one or more statistical measures are associated with at least one of a peak power or a mean power.

17 . The method of claim 15 , wherein the computing the one or more criteria for monitoring the feedback signal comprises computing at least one of:
an upper bound threshold peak power; a lower bound threshold peak power; an upper bound threshold mean power; a lower bound threshold mean power; an upper bound threshold number of samples exceeding a threshold; or a lower bound threshold number of samples exceeding a threshold.

18 . The method of claim 15 , further comprising:
triggering the capturing of the multiple portions of the feedback signal responsive to a register value.

19 . The method of claim 15 , further comprising:
storing, at a memory, the subsequent portion of the feedback signal based the subsequent portion of the feedback signal satisfying the one or more criteria.

20 . The method of claim 15 , further comprising:
refraining from storing, at a memory, the multiple portions of the feedback signal captured for computing the one or more statistical measures.

Assignees

• Analog Devices International Unlimited Co

Inventors

• Summerfield Stephen
• Chandrasekaran Praveen
• Mayer Christopher

Classifications

• 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