KR20190049344A - Method and Apparatus for Digital Pre-Distortion - Google Patents

Abstract

An apparatus and a method for digital predistortion are disclosed. The apparatus and the method for digital predistortion can reduce performance deterioration of a power amplifier operating in a wide frequency region by adjusting a size and a phase of a digital signal input to a peaking amplifier and a carrier amplifier included in a high efficient power amplifier during a predistortion process to linearize a nonlinear output of the power amplifier. To this end, the apparatus for digital predistortion comprises a signal separator, a peak predistortion controller, a carrier predistortion controller, a peak predistortion calculation unit, and a carrier predistortion calculation unit.

Description

[0001] The present invention relates to a digital predistortion apparatus and method,

Embodiments of the present invention relate to a digital predistortion apparatus and method, and more particularly, to a digital predistortion apparatus and method for predistorting a nonlinear output of a power amplifier, To a digital predistortion apparatus and method for improving the performance degradation of a power amplifier operating in a wide frequency range.

The following description merely provides the background information related to the embodiments of the present invention and does not constitute the prior art.

With the development of wireless communication technology and the expansion of the mobile communication market, there are increasing demands for frequency and various methods for increasing the frequency efficiency in order to cope with the increasing frequency demand. Some of the various methods for increasing frequency efficiency are either using higher order modulation or using multi-channel transmission.

However, using these techniques increases the peak to average power ratio (PAPR) of the transmitted signal. Although it is possible to reduce the output of an amplifier (Power Amplifier) in order to linearize the input-output characteristics in a wide frequency range, this method has a disadvantage in that the efficiency of the entire system is greatly reduced.

Therefore, the power amplifier which has the greatest effect on the system efficiency is utilized in the nonlinear section to maximize the overall efficiency, and in order to solve the problem, a technique of linearizing the output of the power amplifier is used.

Recently, Digital Pre-Distortion (DPD) technology, which has relatively simple structure and excellent performance among these linearization methods, is attracting attention. The digital predistortion is a technique for extracting the nonlinear characteristic of the power amplifier from the output signal of the power amplifier and finally linearizing the output of the power amplifier by distorting and transmitting the input signal of the power amplifier using the inverse function of the nonlinear characteristic.

High-power wireless transmission systems of hundreds of watt or more use Doherty power amplifiers, which can improve overall system efficiency by using up to nonlinear periods, while still being efficient. Typically, Doherty power amplifiers use two classes of amplifiers with different turn-on periods, namely a peaking amplifier and a carrier amplifier in parallel. The Doherty power amplifier inputs the same input signal in an analog domain, combines the output of the peaking amplifier and the output of the carrier amplifier using a power combiner, and outputs the combined signal. The Doherty amplifier operates based on an active load modulation scheme, allowing the peaking amplifier and the carrier amplifier to variably operate with the optimum load impedance trajectory depending on the amplitude of the input signal. In addition, the Doherty amplifier basically increases the amplifier average efficiency without compromising the input / output linearity of the signal.

FIG. 1 is a conceptual diagram of a conventional digital predistorter 100. FIG.

A conventional digital predistorter 100 includes a predistorter 110, a DAC 122, an ADC 124, an RF downconverter 132, an RF upconverter 134, a signal separator 140, a power amplifier 150, a power combiner 160, an RF coupler 170, and a predistortion coefficient extractor 180.

The predistortion controller 110 converts the input signal to a predistorted signal and delivers it to the DAC 122. The DAC 122 converts the predistorted digital signal to an analog signal and transmits the converted analog signal to an RF upconverter 132. [ The RF up-converter 132 converts the converted analog signal into an RF signal of a specific frequency. The signal separator 140 separates the RF signal into two signals and transmits them to the power amplifier 150. The peaking amplifier 152 and the carrier amplifier 154 of the power amplifier 150 receive and amplify signals separated from the signal separator 140, respectively. The power combiner 160 combines the two signals received from the picking amplifier 152 and the carrier amplifier 154 to generate one signal. RF coupler 170 receives the signal from power combiner 160 and transfers some of the signal to RF downconverter 134. The RF down-converter 134 down-converts the signal received from the RF coupler 170 to a specific frequency and transmits the down-converted signal to the ADC 124. The ADC 124 converts the analog signal received from the RF down-converter 134 into a digital signal and transmits the digital signal to the predistortion coefficient extractor 180. The predistortion coefficient extraction unit 180 performs predistortion calculation using the received signal. The predistortion coefficient extractor 180 extracts the input and output characteristic functions of the power amplifier 150 based on the signal received from the predistortion controller 110 and the signal received from the ADC 124, Generate the inverse function of the characteristic function. The predistortion controller 110 may pre-distort a signal transmitted to the DAC 122 using an inverse function generated by the predistortion coefficient extraction unit 180. [

However, the two amplifiers included in the Doherty amplifier have different operating environments and operate with different classes of amplifiers, so they have inherent imperfections that can compromise the efficiency and operating bandwidth. To overcome these problems with Doherty amplifiers, a variety of analog solutions have been introduced to derive optimal load modulation operations such as asymmetric designs, nonuniform power distribution designs, gate bias adaptive designs, and extended resonant designs.

However, when these analog schemes are applied, characteristics of elements and matching circuits disposed in the input / output paths of the respective amplifiers change when the frequencies of the input and output signals change. Also, when these analog schemes are applied to a wideband system, the performance of the power amplifier may degrade if the output frequency changes.

Therefore, there is a need for a digital predistortion method and apparatus that can address these problems.

Embodiments of the present invention provide a method and apparatus for predistorting and compensating for each nonlinear characteristic of amplifiers included in a power amplifier and measuring the magnitude of a signal coupling path in a wide frequency range such that a value obtained by combining outputs from amplifiers included in the power amplifier is maximized And to provide a device and method for maximizing the linearity and efficiency of a final output of a power amplifier by reflecting a phase change in a digital transmission signal.

According to an aspect of this embodiment, there is provided an apparatus for processing digital predistortion, comprising: a signal separator for separating a digital input signal into a peak signal and a carrier signal; A peak predistortion controller for generating a peak predistortion signal by distorting the peak signal based on a peak predistortion lookup table; A carrier predistortion controller for generating a carrier predistortion signal by distorting the carrier signal based on a carrier predistortion lookup table; A peak predistortion operator for generating first nonlinear characteristic information based on the peak predistortion signal and generating or updating the peak predistortion lookup table using the first nonlinear characteristic information; And a carrier predistortion calculator for generating second nonlinear characteristic information based on the carrier predistortion signal and generating or updating the carrier predistortion lookup table using the second nonlinear characteristic information. Thereby providing a predistortion device.

According to an aspect of the present invention, there is provided a method of processing digital predistortion comprising: a signal separation process of separating a digital input signal into a peak signal and a carrier signal; A peak predistortion control process of generating a peak predistortion signal by distorting the peak signal based on a peak predistortion lookup table; A carrier predistortion control process of generating a carrier predistortion signal by distorting the carrier signal based on a carrier predistortion lookup table; A peak predistortion computing step of generating first nonlinear characteristic information based on the peak predistortion signal and generating or updating the peak predistortion lookup table using the first nonlinear characteristic information; And a carrier predistortion calculation step of generating second nonlinear characteristic information based on the carrier predistortion signal and generating or updating the carrier predistortion lookup table using the second nonlinear characteristic information A digital predistortion method is provided.

According to an embodiment of the present invention, in digital predistortion of a high efficiency power amplifier, linearity and efficiency deterioration of a power amplifier according to a frequency change is improved, thereby preventing performance deterioration due to frequency variation of a power amplifier applied to a broadband system There is an effect that can be done.

1 is a conceptual diagram of a conventional digital predistorter.
2 is a conceptual diagram of a digital predistorter according to an embodiment of the present invention.
3 is a flow chart illustrating a digital predistortion method in accordance with an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that, in the drawings, like reference numerals are used to denote like elements in the drawings, even if they are shown in different drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0027] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the components of the embodiments according to the present invention, the first, second, i), ii), a), b) and the like can be used. Such a code is intended to distinguish the constituent element from other constituent elements, and the nature of the constituent element, the order or the order of the constituent element is not limited by the code. It is also to be understood that when an element is referred to as being "comprising" or "comprising", it should be understood that it does not exclude other elements unless explicitly stated to the contrary, do.

Hereinafter, a digital predistorter and a method according to embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a conceptual diagram of a digital predistorter according to an embodiment of the present invention.

2, digital predistortion system 200 includes a signal separator 210, a peak predistortion controller 222, a carrier predistortion controller 224, a first DAC 232, a second DAC 234 A first up converter 242, a second up converter 244, a down converter 246, a power amplifier 250, a power combiner 260, an RF coupler 270, a peak predistorter 270, A calculator 282 and a carrier predistortion calculator 284. The digital predistortion system 200 shown in FIG. 2 is according to one embodiment, and not all of the blocks shown in FIG. 2 are required, and in some embodiments, some of the blocks included in the digital predistortion system 200 Can be added, changed or deleted.

The digital predistorter 201 according to an embodiment of the present invention includes a signal predistorter 210, a peak predistortion controller 222, a carrier predistortion controller 224, a peak predistort calculator 282, (284).

The signal separator 210 means a separator for separating the digital transmission signal (input signal X). The signal separator 210 separates the digital transmission signal (input signal X) into two signals. For example, the signal separator 210 includes a peaking signal Xp for transmitting a digital transmission signal to the power amplifier 250, Into a signal Xc.

The signal separator 210 transmits the peaking signal Xp to the peaking amplifier 252 and the carrier signal Xc to the carrier amplifier 254.

The signal separator 210 according to the present embodiment outputs a peaking signal Xp in the digital signal form before converting the digital transmission signal (input signal X) to an analog signal for transmission to the peaking amplifier 252 and the carrier amplifier 254. [ And a carrier signal Xc.

The signal separator 210 separates the digital transmission signal into the picking signal Xp and the carrier signal Xc may be implemented by various methods depending on the implementation method. For example, the signal separator 210 outputs a signal to be transmitted to each amplifier at a voltage level of a digital transmission signal that is turned on by the picking amplifier 252 and the carrier amplifier 254 constituting the power amplifier 250 Can be separated.

Since the peaking amplifier 252 and the carrier amplifier 254 included in the power amplifier 250 are designed to be physically very close to each other, the phase shifted signal is input to avoid mutual interference and the phase shift is performed at the output. The signal separator 210 separates the signal by shifting one of the peaking signal Xp and the carrier signal Xc by 90 degrees in consideration of the phase shift within the power combiner 250.

The peak predistortion controller 222 generates the peaking distortion signal Zp by distorting the peaking signal Xp. Specifically, the peak predistortion controller 222 generates the peaking distortion signal Zp by distorting the peaking signal Xp based on the first nonlinear characteristic information calculated and processed by the peak predistortion calculator 282. [ Here, the peak predistortion controller 222 can distort the peaking signal Xp by using the inverse function of the nonlinear characteristic included in the first nonlinear characteristic information.

The peak predistortion controller 222 may generate a peaking distortion signal Zp using a look-up table (LUT) scheme. The peak predistortion controller 222 stores a peak predistortion lookup table and generates a peaking distortion signal Zp by distorting the peaking signal Xp based on the peak predistortion lookup table. Here, the peak predistortion lookup table means table information generated or updated by a lookup table configuration value included in the first nonlinear characteristic information acquired from the peak predistortion calculator 282. [

The peak predistortion controller 222 generates the peaking distortion signal Zp using a look-up table (LUT) method. However, the present invention is not limited to this, and a polynomial method may be used. To generate a peaking distortion signal Zp. In the case of using the polynomial method, the peak predistortion controller 222 stores polynomial information, and based on the coefficient of the polynomial included in the first nonlinear characteristic information acquired from the peak predistortion calculator 282, And generates a signal Zp.

The peaking distortion signal Zp in the form of a digital signal in the peak predistortion controller 222 is passed through the first DAC 232 and the first up converter 242 to be converted into the first RF signal and then to the peaking amplifier 252 . The first RF signal is amplified through the peaking amplifier 252 and then input to the power combiner 260. Here, the peaking amplifier 252 performs an operation of amplifying the power of the first RF signal whose peaking distortion signal Zp is up-converted to an analog signal. The peaking amplifier 252 may be, but is not necessarily limited to, a Doherty power amplifier.

The carrier predistortion controller 224 generates a carrier distortion signal Zc by distorting the carrier signal Xc. Specifically, the carrier predistortion controller 224 generates the carrier distortion signal Zc by distorting the carrier signal Xc based on the second nonlinear characteristic information calculated and processed by the carrier predistortion calculator 284. Here, the carrier predistortion controller 224 may distort the carrier signal Xc using the inverse function of the nonlinear characteristic included in the second nonlinear characteristic information.

The carrier predistortion controller 224 can generate the carrier distortion signal Zc using a look-up table (LUT) scheme. The carrier predistortion controller 224 stores the carrier predistortion lookup table and generates a carrier distortion signal Zc by distorting the carrier signal Xc based on the carrier predistortion lookup table. Here, the carrier predistortion lookup table means table information generated or updated by a lookup table configuration value included in the nonlinear characteristic information obtained from the carrier predistortion calculator 284.

The carrier predistortion controller 224 generates the carrier distortion signal Zc using a look-up table (LUT) method. However, the carrier predistortion controller 224 is not limited to this and may be a polynomial It is possible to generate the carrier distortion signal Zc. When the polynomial method is used, the carrier predistortion controller 224 stores polynomial information, and based on the coefficients of the polynomial included in the second nonlinear characteristic information acquired from the carrier predistortion calculator 284, And generates a signal Zc.

The carrier distortion signal Zc in the form of a digital signal in the carrier predistortion controller 224 passes through the second DAC 234 and the second upconverter 244 and is converted into a second RF signal and then supplied to the carrier amplifier 254 . The second RF signal is amplified through a carrier amplifier 254 and then input to a power combiner 260. Here, the carrier amplifier 254 performs an operation of amplifying the power of the second RF signal whose carrier distortion signal Zc is up-converted to an analog signal. The carrier amplifier 254 may be, but is not necessarily, a Doherty power amplifier.

The power combiner 260 combines the amplified signals output from each of the peaking amplifier 252 and the carrier amplifier 254 to generate an output signal (output signal Y) of the power amplifier 250.

The output signal of the power combiner 260 is coupled through a coupling from the RF coupler 270 to a downconverter 246 and ADC 236 after the power level is attenuated and converted to a digital output signal. Here, the digital output signal is input to the peak predistortion calculator 282 and the carrier predistortion calculator 284, respectively.

The peak predistortion calculator 282 generates the second nonlinear characteristic information using the digital output signal obtained by digitally converting the peaking distortion signal Zp of the peak predistortion controller 222 and the output signal of the power amplifier 250, And transmits the second nonlinear characteristic information to the peak predistortion controller 222.

Specifically, the peak predistortion calculator 282 uses the digital output signal obtained by digitally converting the peaking distortion signal Zp of the peak predistortion controller 222 and the output signal of the power amplifier 250, Extracts a function for the nonlinear characteristic, and calculates an inverse function for the nonlinear characteristic to generate the first nonlinear characteristic information. Here, the first nonlinear characteristic information may include a configuration value of the lookup table or a coefficient of a polynomial.

The peak predistort calculator 282 transmits the first nonlinear characteristic information to the peak predistortion controller 222 to generate a peak predistortion lookup table or update a predetermined peak predistortion lookup table. Here, the peak predistortion lookup table can be replaced by a polynomial.

The peak predistort calculator 282 stores the first nonlinear characteristic information and controls whether or not the peak nonlinear distortion information is transmitted to the peak predistortion controller 222 according to the change of the first nonlinear characteristic information. In other words, the peak predistortion calculator 282 compares the previously stored first nonlinear characteristic information with the newly generated first nonlinear characteristic information, and determines whether to transmit the first nonlinear specific information according to the comparison result. For example, when the difference between the previously stored first nonlinear characteristic information and the new first nonlinear characteristic information is less than or equal to a predetermined threshold value, the peak predistortion calculator 282 outputs the new first nonlinear characteristic information to the peak predistortion controller 222 And stores it only in the peak predistortion calculator 282 without transmitting. On the other hand, when the difference between the previously stored first nonlinear characteristic information and the new first nonlinear characteristic information exceeds a preset threshold value, the peak predistortion calculator 282 outputs the new first nonlinear characteristic information to the peak predistortion controller 222 And stores it in the peak predistortion calculator 282.

The carrier predistortion calculator 284 generates the second nonlinear characteristic information using the digital output signal obtained by digitally converting the carrier distortion signal Zc of the carrier predistortion controller 224 and the output signal of the power amplifier 250, And transmits the second nonlinear characteristic information to the carrier predistortion controller 224. [

More specifically, the carrier predistortion calculator 284 calculates the carrier predistortion signal Zc of the carrier predistorter 224 using the digital output signal obtained by digitally converting the carrier distortion signal Zc of the carrier predistortion controller 224 and the output signal of the power amplifier 250 Extracts a function for the nonlinear characteristic, and calculates an inverse function for the nonlinear characteristic to generate second nonlinear characteristic information. Here, the second nonlinear characteristic information may include a configuration value of the look-up table or a coefficient of a polynomial.

The carrier predistortion calculator 284 transmits the second nonlinear characteristic information to the carrier predistortion controller 224 to generate a carrier predistorted lookup table or update a predetermined carrier predistorted lookup table. Here, the carrier predistortion lookup table can be replaced with a polynomial.

The carrier predistortion calculator 284 stores the second nonlinear characteristic information and controls whether the carrier predistortion controller 224 transmits the carrier nonlinear characteristic information to the carrier predistortion controller 224 in accordance with the change of the second nonlinear characteristic information. In other words, the carrier predistortion calculator 284 compares the previously stored second nonlinear characteristic information with the newly generated second nonlinear characteristic information, and determines whether to transmit the second nonlinear characteristic information according to the comparison result. For example, when the difference between the previously stored second nonlinear characteristic information and the new second nonlinear characteristic information is less than or equal to a preset threshold value, the carrier predistortion calculator 284 outputs the new second nonlinear characteristic information to the carrier predistortion controller 224 And is stored only in the carrier predistortion calculator 284 without transmitting. On the other hand, when the difference between the previously stored second nonlinear characteristic information and the new second nonlinear characteristic information exceeds a predetermined threshold value, the carrier predistortion calculator 284 outputs the new second nonlinear characteristic information to the carrier predistortion controller 224 And stores it in the carrier predistortion calculator 284. [

The nonlinear characteristics of the power amplifier 250 extracted by the peak predistortion calculator 282 and the carrier predistortion calculator 284 are such that the magnitude of the output signal is nonlinearly proportional to the magnitude of the input signal, to-Amplitude Modulation (AM-to-AM) and an AM-to-PM (Amplitude Modulation-to-Phase Modulation) in which the phase of an output signal varies nonlinearly. That is, changes in the magnitude and phase of the input and output signals of the peaking amplifier 252 constituting the power amplifier 250 and the changes in the magnitude and phase of the input and output signals of the carrier amplifier 254 are detected by the respective sub amplifiers (the peaking amplifier and the carrier amplifier ) Can be independently compensated for using the peak predistortion lookup table and the carrier predistortion lookup table, respectively.

The digital predistorter 201 according to the embodiment of the present invention independently configures the input and predistortion of the sub-amplifiers (peaking amplifier and carrier amplifier) of the high efficiency power amplifier, and this arrangement causes the power combiner 260 can be minimized by changing the frequency of the phase shifter physically fixed. In addition, the digital predistorter 201 can maximize the output of the power amplifier 250 to operate the high-efficiency power amplifier 250 without deteriorating the performance according to the frequency variation.

3 is a flow chart illustrating a digital predistortion method in accordance with an embodiment of the present invention.

The digital predistorter 201 separates the digital transmission signal (input signal X) into two digital signals (S310). The digital predistorter 201 separates the digital transmission signal into a peaking signal Xp and a carrier signal Xc and the peaking signal Xp which is one of the two separated signals is amplified by the peaking amplifier 252 And the other carrier signal Xc is an input signal for amplifying the carrier signal Xc through the carrier amplifier 254. [

The digital predistortion apparatus 201 outputs a peaking signal Xp in the form of a digital signal and a peaking signal Xp in the form of a digital signal before converting the digital transmission signal (input signal X) for amplification through the peaking amplifier 252 and the carrier amplifier 254 to an analog signal. Carrier signal Xc.

The digital predistorter 201 compensates for the nonlinear characteristic of each of the two digital signals using a predetermined predistortion lookup table (S320).

The digital predistorter 201 stores a peak predistortion lookup table and a carrier predistortion lookup table, respectively, and generates a peaking signal Xp and a carrier signal Xc based on a peak predistortion lookup table and a carrier predistortion lookup table, respectively. To compensate for the nonlinear characteristics of the nonlinear device. Here, the compensation of the nonlinear characteristic is performed by distorting the peaking signal Xp and the carrier signal Xc using the inverse function of the nonlinear characteristic based on the constituent values of each of the predistortion lookup tables to obtain the peaking distortion signal Zp and the carrier distortion signal (Zc).

The digital predistorter 201 transmits the peaking distortion signal Zp and the carrier distortion signal Zc to the power amplifier 250 so that the digital-analog conversion and the RF up-conversion processing are performed (S330). The digital predistorter 201 amplifies the peaking distortion signal Zp and the carrier distortion signal Zc of the first RF signal and the second RF signal, respectively, and combines the amplified first RF signal and the second RF signal into one output signal at step S340.

The digital predistorter 201 determines whether the predistortion process is the optimum value based on the output signal (S350).

The digital predistorter 201 compares the predistortion processing value with a predetermined threshold value, and when it is determined that the predistortion processing is performed optimally, the predistortion processing is terminated.

On the other hand, the digital predistorter 201 compares the predistortion processing value with a predetermined threshold value, and if it is determined that additional predistortion processing is necessary, updates the peak predistortion lookup table and the carrier predistortion lookup table, respectively S360). Here, the digital predistorter 201 generates a new peak predistortion lookup table based on the peaking distortion signal Zp and the output signal, and calculates a new carrier predistortion lookup table based on the carrier distortion signal Zc and the output signal And update the lookup table.

In FIG. 3, it is described that each process is sequentially executed, but it is not limited thereto. In other words, the present invention can be applied to changing the procedure shown in FIG. 3 or executing one or more processes in parallel. Therefore, FIG. 3 is not limited to the time series.

Meanwhile, each step of the flowchart shown in FIG. 3 can be implemented as a computer-readable code in a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. That is, a computer-readable recording medium includes a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.), an optical reading medium (e.g., CD ROM, And the like). In addition, the computer-readable recording medium may be distributed over a network-connected computer system so that computer-readable code can be stored and executed in a distributed manner.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept. Various modifications and variations will be possible. Therefore, the embodiments according to the present invention are intended to illustrate rather than limit the technical idea of the embodiments, and the scope of the technical idea of the embodiments is not limited by these embodiments. The scope of protection of embodiments according to the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the embodiments of the present invention.

110: predistortion controller 122: DAC
124: ADC 132: RF up-converter
134: RF downconverter 140: signal separator
150: power amplifier 160: power combiner
170: RF coupler 180: Predistortion coefficient extracting unit
200: digital predistortion system 210: signal separator
222: Peak Predistortion Controller 224: Carrier Predistortion Controller
232: first DAC 234: second DAC
236: ADC 236 242: first up-
244: second up converter 246: down converter
250: power amplifier 260: power combiner
270: RF coupler 270, 282: peak predistortion calculator
284: Carrier predistortion calculator

Claims (8)

An apparatus for processing digital predistortion,
A signal separator for separating a digital input signal into a peak signal and a carrier signal;
A peak predistortion controller for generating a peak predistortion signal by distorting the peak signal based on a peak predistortion lookup table;
A carrier predistortion controller for generating a carrier predistortion signal by distorting the carrier signal based on a carrier predistortion lookup table;
A peak predistortion operator for generating first nonlinear characteristic information based on the peak predistortion signal and generating or updating the peak predistortion lookup table using the first nonlinear characteristic information; And
A carrier predistortion calculator for generating second nonlinear characteristic information based on the carrier predistortion signal and generating or updating the carrier predistortion lookup table using the second nonlinear characteristic information,
And the digital predistortion device. The method according to claim 1,
The peak predistortion arithmetic unit may include:
And generates or updates the peak predistortion lookup table based on the peak predistortion signal and the output signal of the pre-amplified power amplifier. 3. The method of claim 2,
The peak predistortion arithmetic unit may include:
Extracting a function of a nonlinear characteristic of a peaking amplifier included in the power amplifier using the peak predistortion signal and the output signal, calculating an inverse function of the nonlinear characteristic, and outputting the inverse function of the first predistortion lookup table to the peak predistortion lookup table And generates the nonlinear characteristic information. The method according to claim 1,
The carrier predistortion arithmetic section calculates,
And generates or updates the carrier predistortion lookup table based on the carrier predistortion signal and the output signal of the amplified power amplifier. 5. The method of claim 4,
The carrier predistortion arithmetic section calculates,
Extracting a function for the nonlinear characteristic of the carrier amplifier included in the power amplifier using the carrier predistortion signal and the output signal to calculate an inverse function for the nonlinear characteristic, And generates the nonlinear characteristic information. The method according to claim 1,
Wherein the peak predistortion controller comprises:
Acquires the first nonlinear characteristic information from the peak predistortion computing unit, updates the peak predistortion lookup table based on a lookup table configuration value included in the first nonlinear characteristic information, and updates the updated peak predistortion lookup table And the peak signal is distorted using the peak signal. The method according to claim 1,
Wherein the carrier predistortion controller comprises:
Acquires the second nonlinear characteristic information from the carrier predistortion computing unit, updates the carrier predistortion lookup table based on a lookup table configuration value included in the second nonlinear characteristic information, and updates the updated carrier predistortion lookup table Wherein the distortion correcting unit corrects the carrier signal by performing distortion processing on the carrier signal. A method for processing digital predistortion,
A signal separation process for separating a digital input signal into a peak signal and a carrier signal;
A peak predistortion control process of generating a peak predistortion signal by distorting the peak signal based on a peak predistortion lookup table;
A carrier predistortion control process of generating a carrier predistortion signal by distorting the carrier signal based on a carrier predistortion lookup table;
A peak predistortion computing step of generating first nonlinear characteristic information based on the peak predistortion signal and generating or updating the peak predistortion lookup table using the first nonlinear characteristic information; And
Generating a second nonlinear characteristic information based on the carrier predistortion signal and generating or updating the carrier predistortion lookup table using the second nonlinear characteristic information,
Wherein the digital predistortion method comprises:

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