EP1550211A1 - Procede destine a la predistorsion adaptative de valeurs numeriques de donnees brutes et dispositif d'execution correspondant - Google Patents

Procede destine a la predistorsion adaptative de valeurs numeriques de donnees brutes et dispositif d'execution correspondant

Info

Publication number
EP1550211A1
EP1550211A1 EP03773491A EP03773491A EP1550211A1 EP 1550211 A1 EP1550211 A1 EP 1550211A1 EP 03773491 A EP03773491 A EP 03773491A EP 03773491 A EP03773491 A EP 03773491A EP 1550211 A1 EP1550211 A1 EP 1550211A1
Authority
EP
European Patent Office
Prior art keywords
values
raw data
data values
power amplifier
predistortion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03773491A
Other languages
German (de)
English (en)
Inventor
Yingjie Gao
Ralf Kern
Rolf Theisen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of EP1550211A1 publication Critical patent/EP1550211A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H03F1/3247—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits using feedback acting on predistortion circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H03F1/3258—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits based on polynomial terms
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/24—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/207—A hybrid coupler being used as power measuring circuit at the output of an amplifier circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2201/00—Indexing scheme relating to details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements covered by H03F1/00
    • H03F2201/32—Indexing scheme relating to modifications of amplifiers to reduce non-linear distortion
    • H03F2201/3233—Adaptive predistortion using lookup table, e.g. memory, RAM, ROM, LUT, to generate the predistortion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B2001/0408—Circuits with power amplifiers
    • H04B2001/0433—Circuits with power amplifiers with linearisation using feedback

Definitions

  • the invention relates to a method for the adaptive predistortion of digital raw data values for a transmission amplifier having a transmission output stage of a communication device according to the preamble of claim 1 and to an apparatus for performing the method according to the preamble of claim 8.
  • Characterization of such nonlinear power amplifiers can be accomplished by so-called AM-AM conversion, i. H. the amplitude of the output values of the power amplifier dependent on an amplitude of the raw data values, and the AM-PM conversion, d. H. the dependent on the amplitude of the raw data values phase shift in the power amplifier, take place.
  • the non-linearity of the transfer characteristic of real power amplifiers leads to distortions.
  • harmonics of a fundamental frequency are generated, which are present in addition to the fundamental frequency at the output of the power amplifier.
  • the harmonics are generated at these fundamental frequencies, wherein a mixture of the harmonics takes place.
  • Suitable filtering measures can be used to generate generated harmonics suppress.
  • this does not apply to fundamental-frequency intermodulation products due to the harmonic frequency mixing described above.
  • the useful signal or the output signal of the power amplifier is disturbed by the intermodulation products. This disturbance could be suppressed by a suitably high back-off, thereby reducing nonlinearity of the transfer characteristic of the power amplifier and adjusting linearized operation.
  • Supplementing electronic components can also be remedied with regard to intermodulation products, which can not be suppressed by filtering measures. This includes a constructive set-up for adaptive, digital predistortion, which distributes interference close to the channel over a larger frequency spectrum, thereby reducing its amplitudes.
  • the object of the invention is to provide a method for adaptive predistortion for a power amplifier, in which a reduced
  • Computing power is required, and also to provide an apparatus for performing such a method.
  • Raw data values for a transmission output stage having a power amplifier of a communication device comprising the steps of: a) predistorting the raw data values by multiplying the
  • Raw data values with predistortion values from a look-up table for compensating for amplitude-dependent distortions of the power amplifier the look-up table including an association between amplitudes of the raw data values and predistortion values
  • b) returning output signal values of the power amplifier to an adaptation unit c) passing the raw data values to the adaptation unit, d) comparing in time e) adjusting the look-up table based on results of step d), wherein the adaptation unit is discontinuous and interpolating / extrapolating the predistortion values of the lookup table at least for non-occurring raw data values.
  • Predistortion of the raw data values is resorted to. Rather, the adaptation unit operates discontinuously, so that it is purposefully omitted to use a complete collection of associated pairs of raw data values and output signal values of the power amplifier for adaptation. At least those predistortion values for which matching pairs of raw data values and output signal values do not occur due to the discontinuous operation of the adaptation unit are automatically supplemented in the reference table. For this purpose, the associated predistortion values are interpolated or extrapolated, depending on the location of the missing raw data value / output signal value pair within the amplitude spectrum that is used.
  • the adaptation is carried out on the basis of results of step d) within time windows.
  • time windows both raw data values and output signal values are collected and then compared with one another in step d) in order to be able to make a statement about the amplitudes of the power amplifier in terms of amplitude and / or phase of the raw data values.
  • a distance between successive time windows can depend on external parameters which the
  • Affect distortion of the power amplifier, and a desired adjacent channel noise suppression are set.
  • an operating temperature of the power amplifier and its supply voltage have an influence on the distortion behavior of the
  • Power amplifier ie its non-linear transmission characteristics. To what extent a linearization of the Power amplifier is desired, depends on what suppression particular intermodulation products at the output of the power amplifier z. B. is prescribed by a mobile standard.
  • a polynomial can be calculated for each time window, the predistortion values of the reference table being determined on the basis of the function values of the polynomial.
  • coefficients of a polynomial which is fundamentally suitable for describing the course of the output signal values as a function of the raw data values are calculated with the aid of the adaptation unit. For the sake of simplicity, normalization of the output signal values to a total gain of the
  • Power amplifier which is calculated from the maximum value of the output signal values and the maximum value of the raw data values.
  • the use of the polynomial has the advantage of smoothing the history of the predistortion values.
  • the polynomial can also be used for extrapolation / interpolation in the relevant time window of missing raw data value / output signal value pairs.
  • the method can work with both real and complex predistortion values. This depends on whether also a phase distortion of the power amplifier is significant. Whether such a significance exists can easily be determined by means of step d). If, for example, the comparison results in the phases of the raw data values and of the output signal values showing only slight differences, phase correction by means of corresponding predistortion can be dispensed with and real precorrection values are used exclusively. These are real Predistortion values are used to compensate for the amplitude distortion of the power amplifier.
  • a device for linearizing a transmission amplifier of a communication device comprising: a multiplier for multiplying digital raw data values with predistortion values for equalizing amplitude-dependent distortions of the power amplifier, the look-up table having a Assignment between amplitudes of the raw data values and predistortion values, and an adaptation unit to which the output signal values of the power amplifier and the raw data values are supplied synchronized in time and which is adapted to adapt the look-up table, wherein the adaptation unit has a timer which defines a time window for the adaptation the reference table is used.
  • the intended timer has the task of determining the time window within which the raw data values and output signal values for adaptation of the predistortion values are collected, which can then be further processed in the adaptation unit.
  • raw data values V m which contain information to be transmitted by means of a transmission output stage of a mobile communication terminal, reach a predistortion unit 1, which includes a look-up table 2, in which a number N Associations are stored between amplitude intervals of the raw data values and associated predistortion values.
  • the respective predistortion values to be selected thus result from an amplitude of the raw data values V m .
  • a complex multiplier 3 the respective predistortion values to be used from the look-up table 2 are multiplied by the raw data values currently arriving at the complex multiplier 3.
  • the respectively suitable predistortion values are selected with the aid of an amplitude calculation unit 4, at the input of which the raw data values are present and at whose output the magnitude square values of the raw data values are present, which are forwarded to the reference table 2.
  • An output signal of the complex multiplier 3 of the predistortion unit 1 is supplied to a D / A converter 11 for generating an analog signal V d which is applied to the input of a quadrature modulator 5 which modulates the analog signal Vd onto a suitable carrier.
  • An output signal from the quadrature modulator 5 is applied to a power amplifier 6, which provides a desired gain and provides an output signal V a which is transmitted via an antenna (not shown).
  • the power amplifier 6 is chosen for reasons of economy so that the amplitudes of the output signal of the quadrature modulator 5 are at least partially in a non-linear operating range of the power amplifier 6, d. H. a characteristic of the power amplifier 6 is non-linear for at least part of the incoming amplitudes of the output signal of the quadrature modulator 5.
  • the amplitude and phase distortions resulting from the non-linearity of the characteristic curve of the power amplifier 6 can be compensated with the aid of the complex multiplier 3 using the predistortion values in the reference table 2.
  • a real part of the predistortion values is used to compensate for an amplitude error and an imaginary part of the predistortion values to compensate for a phase error of the power amplifier 6.
  • Phase distortion in the used power amplifier 6 significantly comes to light, can be used in a simplified embodiment of the invention with real Vorverzerrungs tone and a simple multiplier, so that only compensation for an amplitude error of the power amplifier 6 is made.
  • the entries in the lookup table 2 are adaptively updated.
  • the procedure is as follows:
  • the output signal V a of the power amplifier 6 is tapped off and supplied to a quadrature demodulator 7 of the transmission output stage, which supplies as well as the Quadradurmodulator 5 with a carrier frequencies
  • Local oscillator 12 in the usual way is in communication.
  • Output values of the power amplifier 6 contains.
  • the signal V r becomes a first input of an adaptation unit 9 which has a second input to which the raw digital data signal V m containing the raw data values is applied.
  • the digital raw data signal V m passes through a delay unit 10 whose task is to delay the raw data signal V m in such a way that temporally mutually corresponding raw data values and output signal values are present at the two inputs of the adaptation unit 9.
  • the adaptation unit 9 has the task of converting any changes in the operating behavior of the power amplifier 6, which influence the amplitude and phase distortions, into a change of the predistortion values in the look-up table 2. To save computing power, the adaptation unit 9 works with the aid of raw data values and output data values which are collected within a time window. Since in contrast to the prior art, no continuous adaptation is made, the selected time window is regularly with respect to the N
  • Amplitude intervals for the raw data values have gaps to be closed by calculation by a suitable algorithm.
  • a suitable value for a delay time V d of the delay unit 10 is first to be calculated.
  • the delay time ⁇ D is estimated by means of the correlation with the digital raw data value signal V m using the digital output signal V r returned within the considered time window, whereby a required accuracy for the delay time ⁇ D can be achieved by appropriate interpolation.
  • the prerequisites for an adaptation of the predistortion values in the lookup table are basically created.
  • both raw data values and output signal values are then collected by means of the adaptation unit 9, the value range for the Amplitudes of the raw data values is divided into the N intervals. Thereafter, the magnitude squared values of the raw data values and the output values of the power amplifier 6 are calculated.
  • Output signal amplitude average for calculating a total gain of the power amplifier 6 are used.
  • the predistortion values in the lookup table 2 are then updated using a comparison of the real and imaginary parts of the raw data and output signal values in a look-up table
  • Amplitude interval n that predistortion value is calculated which optimally compensates for an amplitude and phase distortion of the power amplifier 6 as a multiplication factor for the raw data value from the relevant amplitude interval n.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Algebra (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Pure & Applied Mathematics (AREA)
  • Amplifiers (AREA)
  • Transmitters (AREA)

Abstract

L'invention concerne un procédé de prédistorsion adaptative des valeurs numériques de données brutes destinées à un étage final d'un appareil de communication, cet étage final présentant un amplificateur de puissance. Ce procédé comporte a) la prédistorsion des valeurs de données brutes (Vm) par la multiplication des valeurs de données brutes par des valeurs de prédistorsion issues d'une table de référence (2) pour compenser les distorsions, fonction de l'amplitude et de la phase, de l'amplificateur de puissance (6), la table de référence (2) contenant une affectation entre les amplitudes des valeurs de données brutes et les valeurs de prédistorsion, b) à renvoyer les valeurs de signaux de sortie (Vr) de l'amplificateur de puissance (6) à une unité d'adaptation (9), c) à céder les valeurs de données brutes (Vm) à l'unité d'adaptation (9), d) à comparer dans l'unité d'adaptation les valeurs de données brutes et les valeurs de signaux de sortie qui coïncident temporellement pour évaluer les prédistorsions de l'amplificateur de puissance (6), e) à adapter la table de référence (2) à l'appui des résultats de l'étape d). L'invention vise à économiser une puissance de calcul nécessaire à l'adaptation des valeurs de prédistorsion. A cet effet, l'unité d'adaptation (9) fonctionne en discontinu et les valeurs de prédistorsion de la table de référence (2) sont interpolées/extrapolées au moins pour les valeurs de données brutes (Vm) n'apparaissant pas. L'invention concerne également un dispositif d'exécution du procédé.
EP03773491A 2002-10-09 2003-10-02 Procede destine a la predistorsion adaptative de valeurs numeriques de donnees brutes et dispositif d'execution correspondant Withdrawn EP1550211A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10247034 2002-10-09
DE10247034A DE10247034B3 (de) 2002-10-09 2002-10-09 Verfahren zur adaptiven Vorverzerrung digitaler Rohdatenwerte und Vorrichtung zu dessen Durchführung
PCT/DE2003/003292 WO2004034573A1 (fr) 2002-10-09 2003-10-02 Procede destine a la predistorsion adaptative de valeurs numeriques de donnees brutes et dispositif d'execution correspondant

Publications (1)

Publication Number Publication Date
EP1550211A1 true EP1550211A1 (fr) 2005-07-06

Family

ID=30469825

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03773491A Withdrawn EP1550211A1 (fr) 2002-10-09 2003-10-02 Procede destine a la predistorsion adaptative de valeurs numeriques de donnees brutes et dispositif d'execution correspondant

Country Status (8)

Country Link
US (1) US20060008027A1 (fr)
EP (1) EP1550211A1 (fr)
JP (1) JP2006502630A (fr)
CN (1) CN1703828A (fr)
AU (1) AU2003281930A1 (fr)
DE (1) DE10247034B3 (fr)
RU (1) RU2005114019A (fr)
WO (1) WO2004034573A1 (fr)

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JP4417174B2 (ja) * 2004-05-19 2010-02-17 株式会社日立国際電気 プリディストータ
JP4801074B2 (ja) * 2004-09-15 2011-10-26 テレフオンアクチーボラゲット エル エム エリクソン（パブル） 信号プリディストーションに関する装置と方法
US7653147B2 (en) * 2005-08-17 2010-01-26 Intel Corporation Transmitter control
EP2005580B1 (fr) * 2006-04-10 2010-07-07 Telefonaktiebolaget LM Ericsson (PUBL) Procede de compensation de distorsions de signal dans des amplificateurs composites
US7889810B2 (en) * 2006-12-15 2011-02-15 Pine Valley Investments, Inc. Method and apparatus for a nonlinear feedback control system
CA2708503C (fr) * 2007-12-21 2016-10-25 Astrium Limited Amplificateurs multiport dans des satellites de communication
US8706062B1 (en) * 2008-12-19 2014-04-22 Scintera Networks, Inc. Self-adaptive power amplification
JP2010154042A (ja) * 2008-12-24 2010-07-08 Sumitomo Electric Ind Ltd 歪補償回路
EP2224611A1 (fr) * 2009-02-27 2010-09-01 Astrium Limited Appareil de compensation
US8170508B2 (en) * 2009-05-07 2012-05-01 Rockstar Bidco Lp Pre-distortion for a radio frequency power amplifier
US8913688B1 (en) * 2012-04-30 2014-12-16 Xilinx, Inc. Pre-distortion for a phase interpolator with nonlinearity
CN103001900B (zh) * 2012-12-11 2015-08-05 华为技术有限公司 发射机的发射通道间干扰消除方法及装置
US9300333B2 (en) * 2014-08-01 2016-03-29 Apple Inc. Methods for computing predistortion values for wireless systems
CN105391070B (zh) * 2015-11-13 2018-05-04 天津瑞能电气有限公司 基于主从控制器的新型谐振谐波消去方法
US12603656B2 (en) * 2024-01-29 2026-04-14 Apple Inc. Phase interpolator circuitry with post-distortion linearization

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US6288814B1 (en) * 1994-05-19 2001-09-11 Ortel Corporation In-line predistorter for linearization of electronic and optical signals
US6275685B1 (en) * 1998-12-10 2001-08-14 Nortel Networks Limited Linear amplifier arrangement
US6356146B1 (en) * 1999-07-13 2002-03-12 Pmc-Sierra, Inc. Amplifier measurement and modeling processes for use in generating predistortion parameters
US7058369B1 (en) * 2001-11-21 2006-06-06 Pmc-Sierra Inc. Constant gain digital predistortion controller for linearization of non-linear amplifiers
US6680648B2 (en) * 2002-03-08 2004-01-20 The Aerospace Corporation High power amplifier predistorter system

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Also Published As

Publication number Publication date
DE10247034B3 (de) 2004-02-19
JP2006502630A (ja) 2006-01-19
RU2005114019A (ru) 2006-01-20
CN1703828A (zh) 2005-11-30
US20060008027A1 (en) 2006-01-12
AU2003281930A1 (en) 2004-05-04
WO2004034573A1 (fr) 2004-04-22

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