High efficiency linearization power amplifier for wireless communication

• US 8,620,234 B2
• Filed: 11/21/2011
• Issued: 12/31/2013
• Est. Priority Date: 05/01/2002
• Status: Expired due to Term

• Current Assignee: Dali Wireless Inc. (Dali Systems Co., Ltd.)
• Original Assignee: Dali Systems Co., Ltd.
• Inventors: Yang, Dali, Yang, Jia
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): Sorowar, Golam
• Application Number:
  US13/301,224
• Publication Number:
  US 20120135695A1
• Time in Patent Office: 771 Days
• Field of Search: 455/114.3, 455/63.1, 455/126, 455/296, 455/127.2, 455/113, 455/114.2, 330/149, 375/296, 375/297
• US Class Current: 455/114.3
• 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 predistortion system for linearizing the output of a power amplifier includes a first signal representative of an RF modulated signal and a feedback signal representative of nonlinear characteristics of a power amplifier. The system also includes a predistortion controller, comprising at least one lookup table, adapted to receive the first signal and the feedback signal and to generate a correction factor for correcting the nonlinear characteristics of the power amplifier and combining logic which combines the RF modulated signal with a signal corresponding to the correction factor and supplies it 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 an analog RF modulated signal;

a second input operable to receive a feedback signal representative of nonlinear characteristics of a power amplifier;

a predistortion controller, comprising at least one lookup table, adapted to receive a digitized version of the analog RF modulated signal and a digitized version of the feedback signal and to generate a correction factor for correcting the nonlinear characteristics of the power amplifier;

combining logic which combines the analog RF modulated signal with a signal corresponding to the correction factor and supplies it to the power amplifier to linearize the output of the power amplifier;

a first A-to-D converter coupled to the analog RF modulated signal and operable to generate a first quadrature signal; and

a second A-to-D converter coupled to the feedback signal and operable to generate a second quadrature signal, wherein the correction factor is equal to the square of the first quadrature signal minus the square of the second quadrature signal.

2. The predistortion system of claim 1 wherein the combining logic comprises an analog multiplier.

3. The predistortion system of claim 1 further comprising error logic operable to determine an error between the digitized version of the analog RF modulated signal and the digitized version of the feedback signal.

4. The predistortion system of claim 3 further comprising a multiplier operable to multiple the error by an adaptive factor.

5. The predistortion system of claim 1 wherein the predistortion controller further comprises an address former responsive to the digitized version of the analog RF modulated signal and operable to generate an address supplied to the at least one look-up table.

6. The predistortion system of claim 1 wherein the predistortion controller further comprises an adder operable to provide an entry to the at least one lookup table, wherein the adder receives a scaled error and a previous entry to the at least one lookup table.

7. The predistortion system of claim 1 wherein the at least one lookup table is at least two lookup tables.

8. The predistortion system of claim 7 wherein each of the at least two lookup tables are associated with different operating parameters.

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

receiving an analog RF modulated signal at an input of a predistortion controller;

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

generating a correction factor associated with the nonlinear characteristics of the power amplifier;

combining the analog RF modulated signal with the correction factor to provide a power amplifier input signal;

receiving the power amplifier input signal at an input of the power amplifier;

generating a first quadrature signal using a first A-to-D converter coupled to the digitized version of the RF modulated signal; and

generating a second quadrature signal using a second A-to-D converter coupled to the feedback signal, wherein the correction factor is equal to the square of the first quadrature signal minus the square of the second quadrature signal.

10. The method of claim 9 wherein combining the analog RF modulated signal with the correction factor comprises using an analog multiplier.

11. The method of claim 9 further comprising determining an error between a digitized version of the RF modulated signal and the feedback signal.

12. The method of claim 11 further comprising multiplying the error by an adaptive factor.

13. The method of claim 9 wherein generating the correction factor comprises adding a scaled error and a previous entry to at least one lookup table to provide an entry to the at least one lookup table.

14. The method of claim 13 further comprising generating an address supplied to the at least one lookup table using an address former responsive to the analog RF modulated signal.

15. The method of claim 13 wherein the at least one lookup table is at least two lookup tables.

16. The method of claim 15 wherein each of the at least two lookup tables are associated with different operating parameters.