Source: http://www.google.de/patents/US9077297
Timestamp: 2017-12-12 06:39:00
Document Index: 573597044

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'application No. 200880003130', 'application No. 200880003130', 'application No. 200880003130', 'application No. 200780023875', 'application No. 200880003130', 'application No. 200880003130']

Patent US9077297 - Power amplifier time-delay invariant predistortion methods and apparatus - Google Patentsuche
An embodiment of the invention is a time-delay invariant predistortion approach to linearize power amplifiers in wireless RF transmitters. The predistortion architecture is based on the stored-compensation or memory-compensation principle by using a combined time-delay addressing method, and therefore,...http://www.google.de/patents/US9077297?utm_source=gb-gplus-sharePatent US9077297 - Power amplifier time-delay invariant predistortion methods and apparatus
Veröffentlichungsnummer US9077297 B2
Anmeldenummer US 13/724,157
Auch veröffentlicht unter US8380143, US20080174365, US20130147550, US20160036394
Veröffentlichungsnummer 13724157, 724157, US 9077297 B2, US 9077297B2, US-B2-9077297, US9077297 B2, US9077297B2
Patentzitate (132), Nichtpatentzitate (33), Referenziert von (2), Klassifizierungen (13), Juristische Ereignisse (1)
US 9077297 B2
1. A predistortion system for linearizing the output of a power amplifier comprising:
a first receiver configured to receive a first signal representative of a radio frequency (RF) modulated signal;
a second receiver configured to receive a feedback signal representative of at least one nonlinear characteristic of a power amplifier;
a predistortion controller communicatively coupled with both the first receiver and the second receiver, the predistortion controller comprising at least one lookup table of a predetermined size; and
wherein the at least one lookup table is configured to respond to:
a first input derived from a difference between the square of a quadrature component of the first signal and the square of a quadrature component of the feedback signal, and
a second input derived from a difference between the square of an in-phase component of the first signal and the square of an in-phase component of the feedback signal.
2. The predistortion system of claim 1, further comprising:
a reference path communicatively coupled with the first receiver and the predistortion controller;
a feedback path communicatively coupled with the second receiver and the predistortion controller;
wherein the at least one lookup table is configured to store at least one time-delay value that compensates for a time delay between the reference path and the feedback path.
3. The predistortion system of claim 2 wherein the at least one lookup table is further configured to adaptively update at least one correction value in the lookup table by combining a non-linear correction value of the power amplifier with the at least one time-delay value.
4. The predistortion system of claim 1 wherein the predistortion controller is configured to generate a correction factor for correcting at least one nonlinear characteristic of the power amplifier based on at least the first input or the second input.
5. The predistortion system of claim 1, further comprising combining logic to:
combine the RF modulated signal with a signal corresponding to the correction factor; and
supply the combined RF modulated signal and second signal to the power amplifier to linearize the output of the power amplifier.
6. The predistortion system of claim 1, further comprising a serial shift register for forming an address for the lookup table.
7. The predistortion system of claim 1 wherein the lookup table is addressed by parallel signals.
8. The predistortion system of claim 1 wherein the feedback signal is an analog signal.
This application is a continuation application of U.S. patent applicant Ser. No. 12/021,241, filed Jan. 28, 2008, titled, “Power Amplifier Time-Delay Invariant Predistortion Methods and Apparatus,” which in turn is a continuation-in-part of U.S. patent application Ser. No. 11/262,079, filed Oct. 27, 2005, titled “System and Method for Digital Memorized Predistortion for Wireless Communication” and also claims the benefit of U.S. Provisional Patent Application No. 60/897,746, filed Jan. 26, 2007, titled “Power Amplifier Time-Delay Invariant Predistortion Methods and Apparatus,” and U.S. Provisional Patent Application No. 60/898,312, filed Jan. 29, 2007, titled “Power Amplifier Time-Delay Invariant Predistortion Methods and Apparatus,” the continuation-in-part No. Ser. 11/262/079 of which in turn is a continuation of U.S. patent application Ser. No. 10/137,556, filed May 1, 2002, now U.S. Pat. No. 6,985,704, issued Jan. 10, 2006 titled “System and Method for Digital Memorized Predistortion for Wireless Communication,” all of which are incorporated herein by reference. This application also incorporates by reference U.S. patent application Ser. No. 11/799,239, filed Apr. 30, 2007 and its parent U.S. Provisional Patent Application No. 60/795,820, filed Apr. 28, 2006, titled “High Efficiency Linearization Power Amplifier For Wireless Communication”; related non provisional U.S. patent application Ser. No. 11/962,025, filed Dec. 20, 2007, titled “Power Amplifier Predistortion Methods and Apparatus;” and its parent U.S. Provisional Patent Application No. 60/876,640, filed Dec. 22, 2006, titled “Power Amplifier Predistortion Methods and Apparatus.”
In a typical prior art predistortion system for the linearization of power amplifiers, the system typically contains multiple signal transmission paths, such as a reference path and a feedback path. In a predistortion linearization system, when a signal passes through different signal transmission paths, such as a reference path and a feedback path, the occurrence of a timing difference caused by the distinct signal paths is inevitable. This difference, usually referred to as a time delay, presents significant problems with respect to the accuracy of the predistortion correction. These problems are made worse by the fact that the time delay can vary with environmental conditions including temperature, system conditions including signal power level, system aging, and so on. Therefore, it is difficult to measure in a laboratory such an intrinsic time delay parameter, and, moreover, a parameter for correcting the time-delay cannot be designed as a constant. Many efforts have been made in the prior art to compensate for, reduce or eliminate this time-delay. Traditionally, two methods have been used in prior art predistortion circuits to solve the problem created by the time-delay.
More particularly, the present invention uses, in one implementation, one combined predistortion and time-delay lookup table structure to provide correction factors for both the PA's non-linear distortion and the system's time-delay. This permits the system and method of the present invention to be a self-calibrating solution for performance improvement and nonlinear correction in wireless RF transmitter systems.
In one implementation, the lookup table of the predistortion processing unit, or predistorter, is addressed by a set of time-related addresses that can be structured by a shift register, although parallel addressing may be implemented in some schemes, as discussed in greater detail hereinafter. For present purposes, the shift register technique will be used for illustration. The addressing of the lookup table is based upon a stored-compensation or memory compensation principle that stores information at different time by a vector form and maps the input vector into one of the entries in the lookup table. The set of addressed entries in the lookup table will result in an output signal that is a mapping function of the corresponding input vector. Due to the input address vector comprising different time signals, the output signal of the lookup table is actually related to the different time information, including the current signal and previous N transmitted signals, where N>1 and N is an integer. As a result, the signal stored in each entry of the lookup table can be considered as a combination of all past transmitted signals rather than the sole response of the current input signal. Typically, the bit length of the address vector in the lookup table determines the duration of time-delay signal to be covered.
An input down-converter circuit 20 receives an idealized reference signal VRF from modulator in base station, and is biased by a local oscillator 40, such that it provides an output Vd to an analog-to-digital converter 21. The ADC 21 converts the signal Vd to digital form (as I and Q signals), whereupon it is provided as one input pair to the Digital Predistortion Processor, and more specifically to variables 221 and 22Q, respectively.
A feedback down-converter circuit 26, also biased by a local oscillator 40, receives a raw feedback signal Vo(t) from the output of the PA, and provides a feedback signal Vf to an feedback ADC 25. The digital output of the ADC 25 then provides a second input, i.e. feedback signal, to the Digital Predistortion Processor, and more particularly to variables 241 and 240. The Digital Predistortion, discussed in greater detail below, provides a digital output signal Vf to a DAC 30, which converts the digital signal to an analog form, where it is combined with the modulated RF signal in the multiplier 11.
As shown in FIG. 1, address data formers 32I-32Q receive inputs from the ADC 21 I/Q, and are designed to generate the required signal format for a lookup table 33 I/Q. The data formers 32 I/Q address memory units within the lookup tables 33 I/Q, where the lookup table provides separate I and Q outputs to an adder 31. It will be appreciated that the lookup table 33 can be implemented as one or more lookup tables. The address provided by the address formers 32I-32Q can be considered a lookup-table key or address.
The predistortion controller lookup tables 33I-33Q are designed memory units to store the predistortion signal for high power amplifier linearization. The predistortion signals in the tables are based on the error generated by a comparison of the ideal signal vd and the feedback signal vr and the presented adaptive algorithm. The data stored in the tables 33 I/Q can be updated by adaptive iteration as described hereinafter, and forms digitally indexed data reflecting the nonlinear characteristics of the power amplifier.
v in =v RF v p =v RF F(V) (1)
where vp is the output of predistortion processor generated by a mapping function F of lookup table. Usually, the mapping function F is unknown and is difficult to express mathematically. However, F may be determined adaptively by updating the entries in the lookup table in accordance with the adaptive algorithm to realize all possible mapping that corresponds to the relations with
{0,1}N →v p.
The lookup table therefore maps each set of N-bit input address vector V to a real output V. In fact, the N-dimensional address vector represents the transmitted signal sequences going through power amplifier from the current time though previous N time, expressed by
V(k)=(d 1(k), d2(k), . . . , d N(k))T (2)
where each data di in above vector V is either 1 or 0, expressed as
d i(k)=0 or 1 for 1≦i≦N (3)
A={V(k),V(k−1), . . . ,V(k−M+1)} (4)
Having fully described the invention in detail in detail, including several embodiments and alternatives, those skilled in the art will appreciate that numerous other alternatives and equivalents exist which are within the scope of the present invention. Therefore the invention is intended not to be limited by the above description, but rather only by the appended claims.
US5589797 26. Sept. 1995 31. Dez. 1996 Lucent Technologies Inc. Low distortion amplifier
US5655220 22. Sept. 1995 5. Aug. 1997 Qualcomm Incorporated Reverse link, transmit power correction and limitation in a radiotelephone system
US6252912 24. Dez. 1997 26. Juni 2001 General Dynamics Government Systems Corporation Adaptive predistortion system
US6314142 17. Juni 1997 6. Nov. 2001 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Pre-distortion for a non-linear transmission path in the high frequency range
US6320463 14. Juni 2000 20. Nov. 2001 Alcatel Adaptive digital pre-correction of nonlinearities introduced by power amplifiers
US6356555 19. Juli 1996 12. März 2002 Terayon Communications Systems, Inc. Apparatus and method for digital data transmission using orthogonal codes
US6373902 19. Juni 1998 16. Apr. 2002 Samsung Electronics Co., Ltd Device and method for linearizing transmitter in digital communication system
US6388518 28. März 2001 14. Mai 2002 Hitachi Kokusai Electric Inc. Distortion compensation apparatus
US6489846 22. Mai 2001 3. Dez. 2002 Sony Corporation Distortion compensating device and distortion compensating method
US6741867 17. Nov. 2000 25. Mai 2004 Nec Corporation Non-linear distortion compensation circuit, transmitter device to be employed in the same and mobile communication unit
US7098734 23. Sept. 2004 29. Aug. 2006 Hitachi Kokusai Electric Inc. Distortion-compensated amplifier using predistortion technique
US7123890 20. Febr. 2004 17. Okt. 2006 Andrew Corporation Signal sample acquisition techniques
US7190222 26. Jan. 2005 13. März 2007 Hitachi Kokusai Electric Inc. Predistorter
US8380143 * 28. Jan. 2008 19. Febr. 2013 Dali Systems Co. Ltd Power amplifier time-delay invariant predistortion methods and apparatus
US20010051504 14. März 2001 13. Dez. 2001 Tokuro Kubo Activation method of communications apparatus with a non-linear distortion compensation device
US20020025790 20. Juni 2001 28. Febr. 2002 Akihiko Matsuoka Linear compensated amplifying equipment
US20020193087 7. Juni 2001 19. Dez. 2002 Jaehyeong Kim Method and apparatus for modeling and estimating the characteristics of a power amplifier
US20030112068 13. Febr. 2001 19. Juni 2003 Peter Kenington Amplifier
US20040142667 21. Jan. 2003 22. Juli 2004 Lochhead Donald Laird Method of correcting distortion in a power amplifier
US20050226346 10. Juni 2005 13. Okt. 2005 Takayoshi Ode Distortion compensating apparatus
US20060067426 28. Sept. 2004 30. März 2006 Maltsev Alexander A Multicarrier transmitter and methods for generating multicarrier communication signals with power amplifier predistortion and linearization
US20060109052 31. Okt. 2005 25. Mai 2006 Aryan Saed Adaptive predistortion for a transmit system
US20060121858 19. Aug. 2005 8. Juni 2006 Renesas Technology Corp. Sigma delta transmitter circuits and transceiver using the same
US20060238245 10. März 2006 26. Okt. 2006 Scott Carichner RF amplifier employing active load linearization
US20070190952 15. Febr. 2007 16. Aug. 2007 Texas Instruments Incorporated Linearization of a transmit amplifier
US20130243124 14. Sept. 2012 19. Sept. 2013 Dali Systems Co. Ltd. System and method for digital memorized predistortion for wireless communication
1 Bernardini et al., "Analysis of Different Optimization Criteria for IF Predistortion in Digital Radio Links With Nonlinear Amplifiers", IEEE Trans. On Communications, vol. 45, No. 4, Apr. 1997.
2 Cavers, "Adaptive Behavioue of a Feed-Forward Amplifier Linearizer", IEEE Trans. On Vehicular Technology, vol. 44, No. 1, Feb. 1995, pp. 31-40.
3 Cavers, "Amplifier Linearization Using Digital Predistorter With Fast Adaptation and Low Memory Requirements", IEEE Trans. On Vehicular Technology, vol. 39, No. 4, Nov. 1990, pp. 374-382.
4 Faukner et al., "Adaptive Linearization Using Predistortion-Experimental Results", IEEE Trans. On Vehicular Technology, vol. 43, No. 2, May 1994, pp. 323-332.
5 Fifth Office Action and English Translation for related Chinese patent application No. 200880003130.3 dated Dec. 24, 2013, 8 pages.
6 Final Office Action for U.S. Appl. No. 11/262,079 mailed on May 4, 2009, 13 pages.
7 Final Office Action for U.S. Appl. No. 11/799,239 mailed on Jun. 24, 2010, 10 pages.
8 Final Office Action for U.S. Appl. No. 11/962,025 mailed on Feb. 16, 2011, 17 pages.
9 Final Office Action for U.S. Appl. No. 12/021,241 mailed on Sep. 21, 2010, 31 pages.
10 First Office Action for related Chinese patent application No. 200880003130.3 dated Aug. 5, 2011, 8 pages.
11 Fourth Office Action and English Translation for related Chinese patent application No. 200880003130.3 dated Jul. 8, 2013, 9 pages.
12 Hilborn et al., "An Adaptive Direct Conversion Transmitter", IEEE Trans. On Vehicular Technology, vol. 43, No. 2 May 1994, pp. 223-233.
13 Nagata, "Linear Amplification Technique For Digital Mobile Communications", in Proc. 39th IEEE Vehicular Technology Conference, San Francisco, CA 1989, pp. 159-165.
14 Non-Final Office Action for U.S. Appl. No. 10/137,556 mailed on Dec. 2, 2004, 8 pages.
15 Non-Final Office Action for U.S. Appl. No. 11/262,079 mailed on Aug. 29, 2008, 11 pages.
16 Non-Final Office Action for U.S. Appl. No. 11/262,079 mailed on Dec. 11, 2009, 16 pages.
17 Non-Final Office Action for U.S. Appl. No. 11/262,079 mailed on Mar. 26, 2012, 17 pages.
18 Non-Final Office Action for U.S. Appl. No. 11/799,239 mailed on Oct. 29, 2009, 11 pages.
19 Non-Final Office Action for U.S. Appl. No. 11/962,025 mailed on Jul. 9, 2010, 32 pages.
20 Non-Final Office Action for U.S. Appl. No. 11/962,025 mailed on May 24, 2012, 14 pages.
21 Non-Final Office Action for U.S. Appl. No. 11/962,025 mailed on Sep. 28, 2012, 9 pages.
22 Non-Final Office Action for U.S. Appl. No. 12/021,241 mailed on Apr. 15, 2009, 18 pages.
23 Non-Final Office Action for U.S. Appl. No. 12/021,241 mailed on Dec. 18, 2009, 25 pages.
24 Non-Final Office Action for U.S. Appl. No. 12/021,241 mailed on Feb. 15, 2012, 25 pages.
25 Non-Final Office Action for U.S. Appl. No. 13/301,224 mailed on May 24, 2012, 6 pages.
26 Non-Final Office Action for U.S. Appl. No. 13/301,224 mailed on Oct. 25, 2012, 18 pages.
27 Notice of Allowance for U.S. Appl. No. 10/137,556 mailed on Jul. 6, 2005, 14 pages.
28 Notice of Allowance for U.S. Appl. No. 11/799,239 mailed on Sep. 22, 2011, 7 pages.
29 Notice of Allowance for U.S. Appl. No. 12/021,241 mailed on Sep. 25, 2012, 8 pages.
30 Office Action for related Chinese patent application No. 200780023875.1 dated Dec. 23, 2011, 6 pages.
31 Santella, "Performance of Adaptive Predistorters in Presence of Orthogonal Multicarrier Modulation", International Conference on Telecommunications, pp. 621-626, Melbourne, Australia, Apr. 2-5, 1997.
32 Second Office Action for related Chinese patent application No. 200880003130.3 dated May 3, 2012, 10 pages.
33 Third Office Action for related Chinese patent application No. 200880003130.3 dated Jan. 11, 2012, 13 pages.
Internationale Klassifikation H03F1/32, H03F3/24, H04B1/04
Unternehmensklassifikation H04L1/0044, H04B1/0475, H03F1/3247, H03F1/3241, H04B2001/0425, H03F2201/3233, H03F2200/57, H03F2200/451, H03F3/24, H03F2201/3224