High efficiency linearization power amplifier for wireless communication

• US 10,305,521 B2
• Filed: 08/21/2017
• Issued: 05/28/2019
• Est. Priority Date: 05/01/2002
• Status: Expired due to Term

• Current Assignee: Dali Wireless Inc. (Dali Systems Co., Ltd.)
• Original Assignee: Dali Wireless Inc. (Dali Systems Co., Ltd.)
• Inventors: Yang, Dali, Yang, Jia
• Primary Examiner(s): Pascal, Robert J
• Assistant Examiner(s): Rahman, Hafizur
• Application Number:
  US15/682,431
• Publication Number:
  US 20180097530A1
• Time in Patent Office: 645 Days
• Field of Search: 330 75, 330149, 375296-297, 398193, 4551143, 714786
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2200/57 Separate feedback of real and complex signals being present
• CPC Class Codes: H03F 2201/3215 To increase the output power or efficiency
• CPC Class Codes: H03F 2201/3233 Adaptive predistortion using lookup table, e.g. memory, RAM, ROM, LUT, to generate the predistortion
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/21 with semiconductor devices only H03F3/245 takes precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 2001/0425 with linearisation using predistortion
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and a predistortion system for linearizing an output of a power amplifier include receiving a first input signal representative of an analog RF modulated signal of the predistortion system, receiving a digitized reference signal representative of an idealized reference signal, and receiving a digitized feedback signal representative of nonlinear characteristics of the power amplifier. The method further includes generating, using a lookup table, a predistortion correction signal based on an error between the digitized reference signal and the digitized feedback signal. The first input signal and the predistortion correction signal are combined to produce a predistortion signal that is supplied to the power amplifier to linearize the output of the power amplifier.

Claims

1. A predistortion system for linearizing an output of a power amplifier, the predistortion system comprising:

a first input operable to receive a first input signal representative of an analog RF modulated signal;

a second input operable to receive a digitized reference signal representative of an idealized reference signal;

a third input operable to receive a digitized feedback signal representative of nonlinear characteristics of the power amplifier;

a predistortion controller operable to generate, using a lookup table, a predistortion correction signal based on a first error signal between the digitized reference signal and the digitized feedback signal;

combining logic operable to combine the first input signal and the predistortion correction signal to produce a predistortion signal that is supplied to the power amplifier to linearize the output of the power amplifier; and

error logic operable to determine the first error signal as a difference between a square of the digitized reference signal and a square of the digitized feedback signal.

2. The predistortion system of claim 1, further comprising:

a multiplier operable to multiply the first error signal by an adaptive factor.

3. The predistortion system of claim 1, wherein the digitized reference signal and the digitized feedback signal each include an in-phase component and a quadrature component, and wherein the predistortion controller is operable to form a first component of the predistortion correction signal using the in-phase components and a second component of the predistortion correction signal using the quadrature components.

4. The predistortion system of claim 3, wherein the predistortion controller is operable to perform a first lookup in the lookup table for the in-phase component of the digitized reference signal and a second lookup in the lookup table for the quadrature component of the digitized reference signal.

5. The predistortion system of claim 1, wherein the lookup table receives, as a first lookup table input, an address derived from the digitized reference signal.

6. The predistortion system of claim 5, wherein the predistortion controller further comprises an address former operable to generate the address based on the digitized reference signal.

7. The predistortion system of claim 5, wherein the lookup table receives, as a second lookup table input, a second error signal derived from the first error signal and from a previous value output by the lookup table.

8. A method for linearizing an output of a power amplifier, the method comprising:

receiving a first input signal representative of an analog RF modulated signal of a predistortion system;

receiving a digitized reference signal representative of an idealized reference signal;

receiving a digitized feedback signal representative of nonlinear characteristics of the power amplifier;

generating, using a lookup table, a predistortion correction signal based on a first error signal between the digitized reference signal and the digitized feedback signal;

combining the first input signal and the predistortion correction signal to produce a predistortion signal that is supplied to the power amplifier to linearize the output of the power amplifier; and

determining the first error signal as a difference between a square of the digitized reference signal and a square of the digitized feedback signal.

9. The method of claim 8, further comprising:

multiplying the first error signal by an adaptive factor.

10. The method of claim 8, further comprising:

receiving, as a first input to the lookup table, an address derived from the digitized reference signal.

11. The method of claim 10, further comprising:

receiving, as a second input to the lookup table, a second error signal derived from the first error signal and from a previous value output by the lookup table.

12. The method of claim 8, wherein the digitized reference signal and the digitized feedback signal each include an in-phase component and a quadrature component, the method further comprising:

forming a first component of the predistortion correction signal using the in-phase components; and

forming a second component of the predistortion correction signal using the quadrature components.

13. The method of claim 12, further comprising:

performing a first lookup in the lookup table for the in-phase component of the digitized reference signal; and

performing a second lookup in the lookup table for the quadrature component of the digitized reference signal.