WO2016095528A1 - 一种数字预失真的方法、装置和计算机存储介质 - Google Patents

一种数字预失真的方法、装置和计算机存储介质 Download PDF

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WO2016095528A1
WO2016095528A1 PCT/CN2015/085289 CN2015085289W WO2016095528A1 WO 2016095528 A1 WO2016095528 A1 WO 2016095528A1 CN 2015085289 W CN2015085289 W CN 2015085289W WO 2016095528 A1 WO2016095528 A1 WO 2016095528A1
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distortion
frequency band
frequency
signal
predistortion
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PCT/CN2015/085289
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English (en)
French (fr)
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袁静
戴征坚
潘卫明
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中兴通讯股份有限公司
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits
    • H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems

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  • the present invention relates to the field of digital signal processing, and in particular, to a digital predistortion method, apparatus, and computer storage medium.
  • the multi-band pre-distortion technology mainly has the following two problems: First, the frequency band separation of the feedback distortion data is usually implemented by using an analog filter, which not only increases the hardware resources, but also has complicated design due to the analog filter. The processing consistency between the frequency bands is poor; the second is that the prior art mostly implements pre-distortion in the digital intermediate frequency. If the third-order distortion is considered, the sampling rate is at least three times that of the signal IBW, and the pre-distortion is for the ultra-wideband signal with a small OBW/IBW ratio. Both the processing rate and the training sample sampling rate are high.
  • the present invention is directed to a method, apparatus, and computer storage medium for digital predistortion that can at least partially solve the problem that existing predistortion methods use analog filters to perform frequency separation of feedback distortion data, resulting in increased hardware resources and poor consistency between frequency bands. Pre-distortion at the digital intermediate frequency results in a technical problem with a higher pre-distortion processing rate.
  • a first aspect of the embodiments of the present invention provides a digital predistortion method, including the following steps:
  • the method further includes:
  • the distortion feedback signal of each frequency band is digitally down-converted to generate a baseband distortion feedback signal of each frequency band.
  • the step of updating the multi-dimensional predistortion lookup table corresponding to the frequency band according to the band distortion feedback signal and the baseband signal of the frequency band before the predistortion includes:
  • the step of selecting a frequency band that needs to update the multi-dimensional predistortion lookup table includes:
  • the power of the baseband signal of each frequency band before the pre-distortion is detected, and the frequency band that needs to update the multi-dimensional predistortion lookup table is selected according to the detection result.
  • the step of updating the multi-dimensional predistortion lookup table corresponding to the selected frequency band according to the distortion feedback signal of the selected frequency band and the baseband signal before the predistortion includes:
  • the step of performing digital pre-distortion processing on the baseband signals of each frequency band by querying the corresponding multi-dimensional predistortion lookup table, and generating the digital predistortion signals of each frequency band includes:
  • the multi-dimensional index comprising: a self-index generated according to a baseband signal of the frequency band, a mutual index generated according to a baseband signal of other frequency bands, and an overall index generated according to a baseband signal of all frequency bands;
  • the digital predistortion signal of each frequency band is generated according to the baseband signal of each frequency band and the query result of each frequency band.
  • the step of performing multi-stage frequency selection on the broadband multi-band combined pre-distortion signal, and separating the distortion feedback signals of each frequency band step by step includes:
  • the multi-stage frequency selection of the broadband multi-band combined pre-distortion signal fed back is separated step by step to separate the distortion feedback signals of each frequency band.
  • the step of separating the multi-level frequency selection of the fed back broadband multi-band combined pre-distortion signal according to the frequency band control word and the frequency point information to sequentially separate the distortion feedback signals of each frequency band includes:
  • Each stage of frequency selection is performed according to the following procedure until the feedback feedback signal of all frequency bands in the broadband multi-band combined predistortion signal fed back is separated:
  • a second aspect of the embodiments of the present invention further provides a digital predistortion device, including: a digital predistortion module, a digital upconversion module, a frequency shift combining module, a frequency selection module, and an update module;
  • the digital pre-distortion module is configured to perform digital pre-distortion processing on the baseband signals of each frequency band by querying a corresponding multi-dimensional predistortion lookup table, and generate digital predistortion signals of each frequency band;
  • the digital up-conversion module is configured to digitally up-convert the baseband digital pre-distortion signals of each frequency band to generate intermediate-frequency digital pre-distortion signals of each frequency band;
  • the frequency selection module is configured to perform multi-stage frequency selection on the fed back broadband multi-band combined pre-distortion signal to separate the distortion feedback signals of each frequency band step by step;
  • the updating module is configured to update the multi-dimensional pre-distortion lookup table corresponding to the frequency band according to the distortion feedback signal of the frequency band and the baseband signal of the frequency band before the pre-distortion.
  • the digital pre-distortion module comprises: a plurality of digital pre-distortion sub-modules respectively corresponding to the broadband multi-band signal frequency band, the digital up-conversion module comprising: a plurality of respectively corresponding to the number a digital up-conversion sub-module corresponding to the word pre-distortion sub-module;
  • the digital pre-distortion sub-module is configured to perform digital pre-distortion processing on a corresponding frequency band baseband signal by querying a multi-dimensional pre-distortion look-up table stored therein to generate a digital pre-distortion signal of the frequency band;
  • the digital up-conversion sub-module is configured to digitally up-convert the baseband digital pre-distortion signal transmitted by the corresponding digital pre-distortion sub-module to generate an intermediate frequency digital pre-distortion signal.
  • a digital down conversion module
  • the digital down conversion module is configured to: after the frequency selection module separates the distortion feedback signals of the respective frequency bands, before updating the multidimensional predistortion lookup table, the update module digitally down-converts the frequency band distortion feedback signals to generate basebands of each frequency band. Distortion feedback signal.
  • the update module includes: a power detection module and an adaptive algorithm module;
  • the detecting module is configured to detect a power of a baseband signal in each frequency band before pre-distortion, and select a frequency band that needs to update a multi-dimensional pre-distortion lookup table according to the detection result;
  • the adaptive algorithm module is configured to:
  • the digital pre-distortion sub-module includes: an index generating module, a multi-dimensional lookup table module, and a distortion signal generating module;
  • the index generating module is configured to generate a multi-dimensional index of a frequency band baseband signal corresponding to the digital pre-distortion sub-module, where the multi-dimensional index includes: a self-index generated according to a baseband signal of the frequency band, and a mutual generated according to a baseband signal of other frequency bands Index and overall index generated from baseband signals for all bands;
  • the multi-dimensional lookup table module is configured to query a multi-dimensional pre-distortion lookup table stored by itself according to the multi-dimensional index;
  • the distortion signal generating module is configured to generate a digital distortion signal of the frequency band according to a query result of the multi-dimensional lookup table module and a frequency band baseband signal corresponding to the digital predistortion submodule.
  • the frequency selection module is configured to perform multi-stage frequency selection on the broadband multi-band combined pre-distortion signal fed back according to the frequency band control word and frequency point information to separate the distortion feedback signals of each frequency band.
  • a third aspect of the embodiments of the present invention further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, wherein the computer executable instructions are used in at least one of the methods of the foregoing first aspect.
  • the digital pre-distortion method, device and computer storage amount mechanism provided by the embodiments of the present invention perform digital pre-distortion processing on the baseband signals of each frequency band in the broadband multi-band signal by querying the corresponding multi-dimensional predistortion lookup table, and generate digital pre-distortion of each frequency band.
  • Distortion signal digitally up-converting the baseband digital pre-distortion signal of each frequency band to generate IF digital pre-distortion signals of each frequency band; performing frequency shift combining of each frequency band digital pre-distortion signal to generate a broadband multi-band combined pre-distortion signal;
  • the multi-band frequency pre-distortion signal fed back is subjected to multi-stage frequency selection to separate the distortion feedback signals of each frequency band step by step; and the distortion feedback signal according to the frequency band and the baseband signal of the frequency band before the pre-distortion are updated to correspond to the frequency band corresponding to the frequency band
  • the multidimensional predistortion lookup table is provided to generate IF digital pre-distortion signals of each frequency band.
  • the frequency band separation of the feedback distortion data is directly performed in the baseband signal and the digital domain, the hardware resources are reduced, the processing consistency between the frequency bands is improved, and the pre-distortion is realized at the baseband rate, thereby greatly reducing the DPD processing. Rate; and reduces the requirement for the forward training data sampling rate.
  • FIG. 1 is a schematic flowchart of a method for digital pre-distortion according to Embodiment 1 of the present invention
  • FIG. 2 is a schematic structural diagram of a device for digital predistortion according to Embodiment 2 of the present invention.
  • FIG. 3 is a schematic structural diagram of a multi-dimensional digital pre-distortion module according to Embodiment 2 of the present invention.
  • FIG. 4 is a schematic structural diagram of a multi-stage frequency selection module according to Embodiment 2 of the present invention.
  • FIG. 5 is a schematic structural diagram of a digital predistortion system according to Embodiment 3 of the present invention.
  • FIG. 6 is a schematic flowchart of an adaptive process according to Embodiment 4 of the present invention.
  • FIG. 7 is a schematic structural diagram of a first digital predistortion apparatus according to Embodiment 5 of the present invention.
  • FIG. 8 is a schematic structural diagram of a second digital predistortion apparatus according to Embodiment 5 of the present invention.
  • FIG. 9 is a schematic structural diagram of a third digital predistortion apparatus according to Embodiment 5 of the present invention.
  • FIG. 10 is a schematic structural diagram of a fourth digital predistortion apparatus according to Embodiment 5 of the present invention.
  • FIG. 11 is a schematic structural diagram of a digital pre-distortion sub-module according to Embodiment 5 of the present invention.
  • the predistortion method uses the analog filter to perform frequency separation on the feedback distortion data, which leads to an increase in hardware resources, poor consistency between the frequency bands and pre-distortion in the digital intermediate frequency, resulting in a higher pre-distortion processing rate. problem. Therefore, in the embodiment of the present invention, the predistortion signal of each baseband signal is determined by querying the multi-dimensional predistortion lookup table, and the intermediate frequency digital predistortion signal is formed for the predistortion information numbers, and then the frequency shift combining is performed, and the combined path is generated.
  • the predistortion signal clearly completes the processing of feedback distortion data in the baseband signal and digital domain, which can reduce the cost of hardware resources and improve processing efficiency.
  • Embodiment 1 is a diagrammatic representation of Embodiment 1:
  • a digital predistortion method is provided, as shown in FIG. 1, comprising the following steps:
  • Step 101 Perform digital pre-distortion processing on the baseband signals of each frequency band in the broadband multi-band signal by querying the corresponding multi-dimensional predistortion lookup table, and generate digital predistortion signals of each frequency band.
  • the broadband multi-band signal includes a plurality of frequency band baseband signals.
  • the baseband signal of each frequency band is subjected to digital pre-distortion processing by querying a multi-dimensional predistortion lookup table to generate a digital pre-frequency for each frequency band. Distortion signal.
  • this step includes:
  • the multi-dimensional index comprising: a self-index generated according to the baseband signal of the current frequency band, a mutual index generated according to the baseband signal of the other frequency band, and an overall index generated according to the self-index and the mutual index;
  • the digital predistortion signal of each frequency band is generated according to the baseband signal of each frequency band and the query result of each frequency band.
  • the process of digital predistortion of the baseband signal of one frequency band in the method of this embodiment is:
  • a self-index is generated according to the baseband signal of the frequency band, and a mutual index is generated according to the baseband signal of the other frequency band.
  • a baseband signal of one of the other frequency bands generates a mutual index, for example, a broadband
  • the frequency band signal contains n frequency bands, then n-1 mutual indexes are generated;
  • the digital predistortion signal of the frequency band is generated according to the query result and the baseband signal of the frequency band, for example, the query result and the baseband signal of the frequency band are multiplied to obtain the digital predistortion signal of the frequency band.
  • the digital predistortion processing of the baseband signals in all frequency bands is performed in the manner of performing digital predistortion processing on the baseband signals of the single frequency bands as described above.
  • Step 102 Digitally up-convert the digital pre-distortion signals of each frequency band to generate an intermediate frequency digital pre-distortion signal of each frequency band.
  • the digital predistortion signal generated in step 101 is a baseband digital predistortion signal.
  • the baseband predistortion signal is converted to an intermediate frequency digital predistortion signal.
  • Step 103 Perform frequency shift combining on each frequency band digital frequency predistortion signal to generate a broadband multi-band combined pre-distortion signal.
  • the multi-channel IF digital pre-distortion signals are combined into one digital pre-distortion signal, that is, a broadband multi-band combined pre-distortion signal.
  • Step 104 Perform multi-stage frequency selection on the fed back multi-band combined pre-distortion signal to separate the distortion feedback signals of each frequency band.
  • This step is to complete the frequency separation of the feedback distortion data in the digital domain by the frequency selection algorithm. Specifically, the multi-stage frequency selection of the fed back broadband multi-band combined pre-distortion signal is performed according to the frequency band control word and the frequency point information, and the distortion feedback signal of each frequency band is separated step by step.
  • Step 105 Update the multi-dimensional predistortion lookup table corresponding to the frequency band according to the distortion feedback signal of the frequency band and the baseband signal of the frequency band before the predistortion.
  • the method of the embodiment performs the frequency separation of the feedback distortion data in the digital domain by the frequency selection algorithm, reduces the hardware resources and has good inter-band consistency; realizes pre-distortion at the baseband rate, greatly reduces the DPD processing rate; and reduces the The requirements of the forward training data sampling rate; improve the radio frequency index of the multi-band signal, and improve the output efficiency of the power amplifier to some extent; in addition, the method of the embodiment uses the multi-dimensional pre-distortion index, and the model is more perfect than the prior art. And By indirectly implementing multi-dimensional lookup table functions by combining multiple one-dimensional lookup tables, RAM resources are greatly reduced.
  • the method of the embodiment further includes, between step 104 and step 105, performing digital down-conversion on each frequency band distortion feedback signal to generate a baseband distortion feedback signal of each frequency band.
  • the distortion feedback signal of each frequency band and the signals of each frequency band before pre-distortion are at the same baseband rate, which greatly reduces the processing rate of pre-distortion and the sampling rate of forward training samples.
  • the step 105 may specifically include:
  • the method of this embodiment can algorithmically control which frequency bands need to perform an adaptive update lookup table, and which can bypass or maintain the current predistortion lookup table, thereby improving the stability of the system.
  • the method in this embodiment can detect the power of the baseband signal in each frequency band before the pre-distortion, and select a frequency band that needs to update the multi-dimensional pre-distortion lookup table according to the detection result.
  • the frequency band that needs to be fitted with the predistortion parameter is selected, that is, the frequency band of the lookup table needs to be updated.
  • the method of the embodiment may perform the multi-stage frequency selection of the feedback broadband multi-band combined signal in the digital domain, and the step of separating the IF feedback signals of each frequency band one by one may include:
  • Each stage of frequency selection is performed according to the following procedure until the feedback feedback signal of all frequency bands in the broadband multi-band combined predistortion signal fed back is separated:
  • the method of this embodiment is applicable to dual-band pre-distortion, and is also applicable and compatible for multi-band and single-band application scenarios.
  • This embodiment is not limited to correcting the nonlinear distortion of the power amplifier of the communication system, and is used for other nonlinear distortions involving multiple frequency intermodulation interferences.
  • Embodiment 2 is a diagrammatic representation of Embodiment 1:
  • the embodiment provides a digital pre-distortion device, which is suitable for an ultra-wideband multi-band signal, as shown in FIG. 2, comprising: N multi-dimensional digital pre-distortion modules, N digital up-conversion modules, frequency shift combining modules, Multi-stage frequency selection module, N digital down conversion modules and adaptive algorithm modules;
  • Each band is located at zero-band baseband single/multi-carrier CFR post-signal XA-XN as the input signal to the multi-dimensional digital pre-distortion DPDA-DPDN.
  • Multi-dimensional index generation and table lookup operations are performed inside the predistortion module to obtain a multi-band baseband predistortion signal XdpdA-XdpdN.
  • the baseband pre-distortion signal of each frequency band is digitally upconverted by fA-upconversion fN and frequency shifting, and finally the intermediate frequency broadband multi-band predistortion signal Xdpd is obtained.
  • FIG. 3 it is an internal structure of a multi-dimensional digital pre-distortion module A in FIG. 2, including: a self-index generation module and a mutual index generation module; and the structure of multi-dimensional digital pre-distortion A to multi-dimensional digital pre-distortion N is the same.
  • the implementation of the KDK (Digital Pre-Distortion) in the K-band is not only related to the baseband single/multi-carrier signal X k of the frequency band, but also the signal X j (j ⁇ k) of other frequency bands, which is used for each frequency band.
  • the DPD lookup table is implemented by a multi-dimensional index, and the predistortion implementation methods defined as the self-index P k , the mutual index P j (j ⁇ k), and the overall index P s lookup table structure are:
  • each band predistortion lookup table is N+1.
  • the direct implementation of an N+1-dimensional lookup table is huge, and the lookup process requires a lot of operations.
  • the N+1-dimensional index in the model is split into N+1 1-dimensional indexes, and the sum of N+1 1-dimensional indexes is used as a simplified result of the N+1-dimensional index.
  • LSB be the lower sideband
  • HSB be the upper sideband.
  • the simplified multi-dimensional digital pre-distortion can be expressed as:
  • LUT LL , LUT LH , and LUT LS represent the predistortion multi-dimensional lookup table after the lower sideband split
  • LUT HH , LUT HL , and LUT HS represent the predistortion multidimensional lookup table after the upper sideband split
  • P LSB , P HSB , and P S represent the multidimensional table indexes calculated by the index generation module, respectively.
  • k self represents the memory depth corresponding to the self-indexing model
  • k inter represents the memory depth corresponding to the mutual index model
  • k sum represents the memory depth corresponding to the overall index.
  • the adaptive algorithm module performs the following functions: acquiring the baseband rate single-carrier or multi-carrier CFR post-signal XA-XN of each frequency band before pre-distortion, and the intermediate-frequency wideband multi-band nonlinear distortion signal Y as the training data of the adaptive algorithm. .
  • the feedback training data is first separated by the multi-stage frequency selection algorithm to separate the intermediate frequency feedback signal of the frequency band to be fitted, and then digitally down-converted fA-downconversion fN to obtain a baseband feedback signal having the same rate as the forward signal.
  • the adaptive algorithm firstly selects the frequency band that needs to be fitted with the predistortion parameter according to the power detection of the forward signal of each frequency band, and then adaptively trains the frequency band that needs to be fitted with the predistortion parameter to obtain the predistortion coefficient, and the adaptive algorithm includes but not limited thereto.
  • the adaptive algorithm includes but not limited thereto.
  • any model parameters will eventually be converted into a lookup table, closer to the forward link to achieve baseband predistortion.
  • FIG. 4 it is a schematic diagram of the internal structure of the multi-stage frequency selection module, and the multi-stage frequency selection of the feedback broadband multi-band combining is used to separate the intermediate frequency predistortion signals of each frequency band step by step; the specific process is as follows:
  • Step 1 Obtain a system band number control word, determine a level of the frequency selection algorithm, and an algorithm parameter;
  • Step 3 performing frequency shifting according to frequency information of each frequency band, moving the frequency band K to a negative frequency, and moving the other frequency bands to a positive frequency;
  • Step 4 after the frequency shift, the signal IQ is separated;
  • Step 5 performing FFT transformation on the separated I and Q channels respectively, to obtain I', Q';
  • Step 6 taking the original I way Q path and the transformed I', Q', performing signal IQ recombination, to obtain positive and negative frequency separated intermediate frequency signals IF_1, IF_2;
  • Step 7 taking the signal separated by the positive and negative frequency bands, the center frequency of the negative frequency signal is shifted to zero frequency, that is, the K-band data; taking the center frequency of the positive frequency signal to the zero frequency is the combined signal of other frequency bands, completing the level K Frequency selection
  • Embodiment 3 is a diagrammatic representation of Embodiment 3
  • the embodiment describes a specific process for applying the method of the present invention to a dual-band scenario of a transmission link of a communication system.
  • the embodiment provides a system for digital pre-distortion, including: a multi-dimensional digital pre-distortion module and a digital Upconversion module, frequency shift combining module, DAC module, power amplifier module, coupler, attenuator, ADC module, other digital processing algorithms, multi-stage frequency selection module, digital down conversion module and adaptive algorithm module; specific predistortion
  • the process is as follows:
  • Step 1 The dual-band baseband signal passes through the multi-dimensional digital pre-distortion modules DPD1 and DPD2 to obtain a dual-band baseband pre-distortion signal.
  • Step 2 the dual-band pre-distortion signals are respectively digitally up-converted to obtain a high-speed pre-distortion signal
  • Step 3 the dual-band high-speed predistortion signal is combined by frequency shifting to obtain an intermediate frequency predistortion combined signal
  • Step 4 the intermediate frequency predistortion signal is obtained by the digital-to-analog conversion DAC module to obtain a radio frequency predistortion signal;
  • Step 5 the predistortion signal passes through the power amplifier to obtain a linearly corrected power amplification signal
  • Step 6 The power amplifier transmitting signal is coupled back through the attenuator to obtain feedback pre-distortion training data of the broadband combining;
  • Step 7 the feedback predistortion training data is obtained by the analog-to-digital converter ADC module to obtain discrete sampling training samples;
  • Step 8 Obtain the aligned forward and feedback training data through other intermediate frequency digital preprocessing
  • Step 9 The broadband combined feedback training data is subjected to multi-stage frequency selection to obtain an intermediate frequency signal of the frequency band to be fitted;
  • Step 10 the frequency-selected signal is digitally down-converted to obtain a baseband feedback training sample
  • step 11 the predistortion forward and feedback training data are adaptively trained to obtain a multidimensional predistortion table.
  • step 12 the multi-dimensional predistortion lookup table is newly added to the forward link predistortion module to complete the predistortion function.
  • Embodiment 4 is a diagrammatic representation of Embodiment 4:
  • the digital predistortion method of the present invention can be applied to multi-band pre-distortion and is also compatible with single-band pre-distortion function.
  • the following describes the process of adaptive pre-distortion in the digital pre-distortion method, that is, the process of updating the pre-distortion look-up table by using feedback data, as shown in FIG. 6 . Shown, including:
  • Step 601 collecting pre-distortion training samples
  • the predistortion training samples in this step are feedback predistortion training data of the wideband combined;
  • Step 602 Perform other intermediate frequency digital signal processing
  • Step 603 the system configuration parameter acquisition, including acquiring frequency band information and frequency point information;
  • Step 604 determine whether multi-dimensional pre-distortion processing is required, if multi-dimensional pre-distortion is required, proceed to step 605, otherwise go to step 609;
  • Step 605 The multi-band combined training sample passes, and the multi-stage frequency selection module separates the intermediate frequency training data of each frequency band step by step.
  • Step 606 The intermediate frequency training samples of each frequency band are subjected to down-conversion and frequency shift to obtain baseband training samples.
  • Step 607 power detection of each frequency band, and dividing the frequency band to be fitted and the frequency band not required to be matched according to signal power detection of each frequency band;
  • Step 608 Generate a multi-dimensional index for the frequency band to be fitted, and maintain a lookup table for the unfitting frequency band;
  • Step 609 predistortion parameter adaptive parameter extraction. You can choose LS, LMS or other adaptive algorithms.
  • step 610 a predistortion lookup table is generated. Integrate all band predistortion lookup tables
  • step 611 the predistortion lookup table is updated to the forward link to complete the adaptation process.
  • Embodiment 5 is a diagrammatic representation of Embodiment 5:
  • the embodiment provides a digital pre-distortion device, including: a digital pre-distortion module, a digital up-conversion module, a frequency shift combining module, a frequency selection module, and an update module;
  • the digital pre-distortion module is configured to perform digital pre-distortion processing on each baseband baseband signal by querying a corresponding multi-dimensional predistortion lookup table to generate a digital predistortion signal of each frequency band;
  • the digital up-conversion module is configured to digitally up-convert the baseband digital pre-distortion signals of each frequency band to generate intermediate-frequency digital pre-distortion signals of each frequency band;
  • the frequency selection module is configured to perform multi-stage frequency selection on the fed back multi-band combined pre-distortion signal to separate the distortion feedback signals of each frequency band step by step;
  • the updating module is configured to perform a distortion feedback signal according to a frequency band and a frequency band of the pre-distortion
  • the baseband signal updates the multi-dimensional predistortion lookup table corresponding to the frequency band.
  • the digital pre-distortion module includes: a plurality of digital pre-distortion sub-modules respectively corresponding to the broadband multi-band signal frequency band, where the digital up-conversion module includes: a plurality of The digital up-conversion sub-module corresponding to the pre-distortion sub-module;
  • FIG. 8 includes n digital pre-distortion sub-modules and n digital up-conversion sub-modules, and n corresponds to the number of frequency bands of the broadband multi-frequency signal;
  • the digital pre-distortion sub-module is configured to perform digital pre-distortion processing on a corresponding frequency band baseband signal by querying a multi-dimensional pre-distortion look-up table stored therein to generate a digital pre-distortion signal of the frequency band;
  • the digital up-conversion sub-module is configured to digitally up-convert the baseband digital pre-distortion signal transmitted by the corresponding digital pre-distortion sub-module to generate an intermediate frequency digital pre-distortion signal.
  • the apparatus of this embodiment may further include: a digital down conversion module;
  • the digital down conversion module is configured to: after the frequency selection module separates the distortion feedback signals of the respective frequency bands, before updating the multidimensional predistortion lookup table, the update module digitally down-converts the frequency band distortion feedback signals to generate basebands of each frequency band. Distortion feedback signal.
  • the update module in the apparatus of this embodiment includes: a power detection module and an adaptive algorithm module;
  • the detecting module is configured to detect a power of a baseband signal in each frequency band before pre-distortion, and select a frequency band that needs to update a multi-dimensional pre-distortion lookup table according to the detection result;
  • the adaptive algorithm module is configured to:
  • the digital pre-distortion sub-module includes: an index generating module, a multi-dimensional lookup table module, and a distortion signal generating module;
  • the index generating module is configured to generate a multi-dimensional index of a frequency band baseband signal corresponding to the digital pre-distortion sub-module, where the multi-dimensional index includes: a self-index generated according to a baseband signal of the frequency band, and a mutual generated according to a baseband signal of other frequency bands Index and overall index generated from baseband signals for all bands;
  • the multi-dimensional lookup table module is configured to query a multi-dimensional pre-distortion lookup table stored by itself according to the multi-dimensional index;
  • the distortion signal generating module is configured to generate a digital distortion signal of the frequency band according to a query result of the multi-dimensional lookup table module and a frequency band baseband signal corresponding to the digital predistortion submodule.
  • the frequency selection module is configured to perform multi-stage frequency selection on the broadband multi-band combined pre-distortion signal fed back according to the frequency band control word and frequency point information to separate the distortion feedback signals of each frequency band.
  • the embodiment of the present invention further provides a computer storage medium, where the computer storage medium stores computer executable instructions, and the computer executable instructions are used in at least one of the methods of digital predistortion described in the foregoing embodiment, specifically The method shown in Figures 1 and / or Figure 6.
  • the computer storage medium may be a storage medium such as an optical disk, a mobile hard disk, a USB flash drive, a magnetic tape, or the like, and may be a non-transitory storage medium.

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Abstract

本发明实施例公开了一种数字预失真的方法和装置。本发明的数字预失真的方法包括：通过查询对应的多维预失真查找表对宽带多频段信号中各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；分别对各频段的基带数字预失真信号进行数字上变频生成各频段中频数字预失真信号；对各频段中频数字预失真信号进行移频合路生成宽带多频段合路预失真信号；对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。本发明实施例还公开了一种计算机存储介质。

Description

一种数字预失真的方法、装置和计算机存储介质 技术领域
本发明涉及数字信号处理领域，尤其涉及一种数字预失真的方法、装置和计算机存储介质。
背景技术
在移动通信***中，许多模拟器件，特别是功率放大器都有非线性效应，产生带内失真和带外频谱扩展。带内失真会降低***性能，带外频谱扩展会干扰邻近信道。目前减小非线性效应的方法主要有功率回退技术、包络消除和恢复技术、前馈线性化技术和数字预失真技术等。其中功率回退会牺牲功放的效率，前馈线性化技术结构复杂、成本高且自适应性差，而数字预失真技术稳定性高，适用带宽较宽，实现成本低，是目前移动通信***中功放线性化的重要手段。近年来移动通信发展的趋势是，频谱资源稀缺，各个运营商拿到的频谱并不连续，总体趋势是工作带宽(Occupied Band Width，OBW)小，瞬时带宽(Information Band Width，IBW)相对很大，即超宽带多频段配置。这种配置下DPD(数字预失真)对资源要求越来越高，且对整个IBW内的链路要求也较高。多频段DPD技术正是针对这种应用场景而提出。
现有的专利和文献中，多频段预失真技术主要有以下两个问题：一是对反馈失真数据的频段分离通常使用模拟滤波器实现，不仅增加了硬件资源，且由于模拟滤波器设计复杂，各频段间处理一致性差；二是现有技术大多在数字中频实现预失真，若考虑三阶失真，采样速率至少是信号IBW的三倍，对于OBW/IBW比值很小的超宽带信号，预失真处理速率和训练样本采样速率都较高。
发明内容
本发明期望提供一种数字预失真的方法、装置和计算机存储介质，能够至少部分解决现有预失真方法使用模拟滤波器对反馈失真数据进行频段分离导致硬件资源增加、各频段之间一致性差和在数字中频实现预失真导致预失真处理速率较高的技术问题。
本发明实施例第一方面提供一种数字预失真的方法，包括如下步骤：
通过查询对应的多维预失真查找表对宽带多频段信号中各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；
分别对各频段的数字预失真信号进行数字上变频生成各频段中频数字预失真信号；
对各频段中频数字预失真信号进行移频合路生成宽带多频段合路预失真信号；
对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；
根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。
可选地，在逐级分离出各频段的失真反馈信号之后，更新多维预失真查找表之前，所述方法还包括：
分别对各频段的失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。
可选地，所述根据频段失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表的步骤包括：
选取需要更新多维预失真查找表的频段；
根据选取频段的失真反馈信号和预失真前的基带信号更新所述选取频段对应的多维预失真查找表。
可选地，所述选取需要更新多维预失真查找表的频段的步骤包括：
检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多维预失真查找表的频段。
可选地，所述根据选取频段的失真反馈信号和预失真前的基带信号更新所述选取频段对应的多维预失真查找表的步骤包括：
根据选取频段的失真反馈信号和预失真前的基带信号对所述选取频段进行自适应训练得到所述选取频段的多维预失真参数；
根据所述选取频段的多维预失真参数生成多维预失真查找表；
根据生成的多维预失真查找表更新所述选取频段对应的多维预失真查找表。
可选地，所述通过查询对应的多维预失真查找表对各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号的步骤包括：
生成各频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所有频段基带信号生成的整体索引；
根据各频段基带信号的多维索引查询各频段对应的多维预失真查找表；
根据各频段基带信号和各频段的查询结果生成各频段的数字预失真信号。
可选地，所述对所述宽带多频段合路预失真信号进行多级频率选择，逐级分离出各频段的失真反馈信号的步骤包括：
根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
可选地，所述根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号的步 骤包括：
根据频段数控制字确定多级频率选择的级数；
按照以下过程进行每一级频率选择直至分离出反馈的所述宽带多频段合路预失真信号中所有频段的失真反馈信号：
根据反馈的所述宽带多频段合路预失真信号中各频段的频点信息进行移频，将与当前频率选择级数对应的频段移到负频、其他频段移到正频；
对移频后的带宽多频合路预失真信号进行IQ正交分离；
分别对分离后的I路预失真信号和Q路预失真信号进行FFT变换；
对所述I路预失真信号、Q路预失真信号、FFT变换后的I路预失真信号、FFT变换后的Q路预失真信号进行IQ重组得到正频预失真信号和负频预失真信号；
将所述负频预失真信号的中心频点移到零频得到与当前频率选择级数对应的频段的失真反馈信号，将所述正频预失真信号的中心频点移到零频。
本发明实施例第二方面还提供了一种数字预失真的装置，包括：数字预失真模块、数字上变频模块、移频合路模块、频率选择模块和更新模块；
所述数字预失真模块，配置为通过查询对应的多维预失真查找表对各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；
所述数字上变频模块，配置为分别对各频段的基带数字预失真信号进行数字上变频生成各频段中频数字预失真信号；
所述频率选择模块，配置为对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；
所述更新模块，配置为根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。
可选地，所述数字预失真模块包括：多个分别与宽带多频段信号频段对应的数字预失真子模块，所述数字上变频模块包括：多个分别与所述数 字预失真子模块对应的数字上变频子模块；
所述数字预失真子模块，配置为通过查询自身存储的多维预失真查找表对与之对应的频段基带信号进行数字预失真处理，生成该频段的数字预失真信号；
所述数字上变频子模块，配置为对与之对应的数字预失真子模块传输的基带数字预失真信号进行数字上变频生成中频数字预失真信号。
可选地，数字下变频模块；
所述数字下变频模块，配置为频率选择模块分离出各频段的失真反馈信号之后，所述更新模块更新多维预失真查找表之前，分别对各频段失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。
可选地，所述更新模块包括：功率检测模块和自适应算法模块；
所述检测模块，配置为检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多维预失真查找表的频段；
所述自适应算法模块，配置为：
根据选取频段的失真反馈信号和预失真前的基带信号对所述选取频段进行自适应训练得到所述选取频段的多维预失真参数；
根据所述选取频段的多维预失真参数生成多维预失真查找表；
根据生成的多维预失真查找表更新所述选取频段对应的多维预失真查找表。
可选地，所述数字预失真子模块包括：索引生成模块、多维查找表模块和失真信号生成模块；
所述索引生成模块，配置为生成与所述数字预失真子模块对应的频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所有频段基带信号生成的整体索引；
所述多维查找表模块，配置为根据所述多维索引查询自身存储的多维预失真查找表；
所述失真信号生成模块，配置为根据所述多维查找表模块的查询结果和与所述数字预失真子模块对应的频段基带信号生成该频段的数字失真信号。
可选地，所述频率选择模块，配置为根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
本发明实施例第三方面还提供一种计算机存储介质，所述计算机存储介质中存储有计算机可执行指令，所述计算机可执行指令用于前述第一方面所述方法的至少其中之一。
本发明实施例提供的数字预失真的方法、装置和计算机存储额机制，通过查询对应的多维预失真查找表对宽带多频段信号中各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；分别对各频段的基带数字预失真信号进行数字上变频生成各频段中频数字预失真信号；对各频段中频数字预失真信号进行移频合路生成宽带多频段合路预失真信号；对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。在本发明实施例提供的技术方案中，直接在基带信号和数字域完成反馈失真数据的频段分离，减少硬件资源、提高频段间处理一致性；在基带速率下实现预失真，大大降低了DPD处理速率；且降低了对前向训练数据采样速率的要求。
附图说明
图1为本发明实施例一提供的一种数字预失真的方法的流程示意图；
图2为本发明实施例二提供的一种数字预失真的装置的结构示意图；
图3为本发明实施例二提供的一种多维数字预失真模块的结构示意图；
图4为本发明实施例二提供的一种多级频率选择模块的结构示意图；
图5为本发明实施例三提供的一种数字预失真的***的结构示意图；
图6为本发明实施例四提供的一种自适应过程的流程示意图；
图7为本发明实施例五提供的第一种数字预失真的装置的结构示意图；
图8为本发明实施例五提供的第二种数字预失真的装置的结构示意图；
图9为本发明实施例五提供的第三种数字预失真的装置的结构示意图；
图10为本发明实施例五提供的第四种数字预失真的装置的结构示意图；
图11为本发明实施例五提供的一种数字预失真子模块的结构示意图。
具体实施方式
通过研究发现，在现有技术中，预失真方法使用模拟滤波器对反馈失真数据进行频段分离将导致硬件资源增加，各频段之间一致性差和在数字中频实现预失真导致预失真处理速率较等问题。故本发明实施例中，通过查询多维预失真查找表确定出各个频段基带信号的预失真信号，并对这些预失真信息号形成中频数字预失真信号，最后进行移频合路，将生成合路预失真信号，显然在基带信号和数字域中完成了反馈失真数据的处理，这样能够降低硬件资源的成本，提高处理效率。下面通过具体实施方式结合附图对本发明作进一步详细说明，应当理解为，以下所说明的优选实施例仅用于说明和解释本发明，并不用于限定本发明。
实施例一：
考虑到现有预失真方法使用模拟滤波器对反馈失真数据进行频段分离导致硬件资源增加、各频段之间一致性差和在数字中频实现预失真导致预失真处理速率较高的技术问题，本实施例提供了一种数字预失真的方法，如图1所示，包括如下步骤：
步骤101：通过查询对应的多维预失真查找表对宽带多频段信号中各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号。
本实施例方法中宽带多频段信号含多个频段的基带信号，本实施例方法对于每个频段基带信号均通过查询多维预失真查找表的方式来进行数字预失真处理生成每个频段的数字预失真信号。
具体地，本步骤包括：
生成各频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所述自索引和所述互索引生成的整体索引；
根据各频段基带信号的多维索引查询各频段对应的多维预失真查找表；
根据各频段基带信号和各频段的查询结果生成各频段的数字预失真信号。
以一个频段的基带信号为例，本实施例方法中对一个频段基带信号进行数字预失真的处理过程为：
首先，根据本频段基带信号生成自索引，根据其他频段基带信号生成互索引，根据所述自索引和所述互索引生成的整体索引，其中一个其他频段基带信号生成一个互索引，例如有宽带多频段信号包含n个频段，那么就会生成n-1个互索引；
然后，根据自索引、互索引以及整体索引查询对应的多维预失真查找 表得到一个查询结果；
最后，根据查询结果和本频段基带信号生成本频段的数字预失真信号，例如将查询结果和本频段基带信号相乘得到本频段的数字预失真信号。
本实施例按照上述对单个频段的基带信号进行数字预失真处理的方式完成所有频段的基带信号的数字预失真处理。
步骤102：分别对各频段的数字预失真信号进行数字上变频生成各频段中频数字预失真信号。
在步骤101中生成的数字预失真信号为基带数字预失真信号，本步骤是将基带预失真信号变换至中频数字预失真信号。
步骤103：对各频段中频数字预失真信号进行移频合路生成宽带多频段合路预失真信号。
本步骤是将多路中频数字预失真信号合并为一路数字预失真信号，即宽带多频段合路预失真信号。
步骤104：对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
本步骤是通过频率选择算法在数字域完成反馈失真数据的频段分离。具体地，根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
步骤105：根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表
本实施例方法通过频率选择算法在数字域完成反馈失真数据的频段分离，减少了硬件资源的同时频段间一致性好；在基带速率下实现预失真，大大降低了DPD处理速率；且降低了对前向训练数据采样速率的要求；改善了多频段信号的射频指标，一定程度上提高了功放输出效率；另外，本实施例方法使用多维度预失真索引，与现有技术相比，模型更加完善，且 通过结合多个一维查找表间接实现多维查找表功能，大大减少了RAM资源。
为进一步在基带速率上实现预失真，本实施例方法在步骤104和步骤105之间还包括：分别对各频段失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。这样各频段的失真反馈信号与预失真前各频段的信号均在在相同基带速率下，大大降低预失真的处理速率和前向训练样本采样速率。
考虑到频段间的独立控制需求，本实施例方法中步骤105可以具体包括：
选取需要更新多维预失真查找表的频段；
根据选取频段的失真反馈信号和预失真前的基带信号更新所述选取频段对应的多维预失真查找表。
本实施例方法可以算法控制哪些频段需要进行自适应更新查找表，哪些可以旁路或保持当前预失真查找表格，提升了***的稳定性。
可选地，本实施例方法可以检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多维预失真查找表的频段。
例如根据各频段前向信号的功率检测选择需要拟合预失真参数的频段，即需要更新查找表的频段。
本实施例方法可以在数字域对反馈的宽带多频段合路信号进行多级频率选择逐一分离出各频段中频反馈信号的步骤可包括：
根据频段数控制字确定多级频率选择的级数；
按照以下过程进行每一级频率选择直至分离出反馈的所述宽带多频段合路预失真信号中所有频段的失真反馈信号：
根据反馈的所述宽带多频段合路预失真信号中各频段的频点信息进行移频，将与当前频率选择级数对应的频段移到负频、其他频段移到正频；
对移频后的带宽多频合路预失真信号进行IQ正交分离；
分别对分离后的I路预失真信号和Q路预失真信号进行FFT变换；
对所述I路预失真信号、Q路预失真信号、FFT变换后的I路预失真信号、FFT变换后的Q路预失真信号进行IQ重组得到正频预失真信号和负频预失真信号；
将所述负频预失真信号的中心频点移到零频得到与当前频率选择级数对应的频段的失真反馈信号，将所述正频预失真信号的中心频点移到零频。
本实施例方法适用于双频段预失真，也对多频段和单频段的应用场景都适用并兼容。本实施例不限于校正通信***功率放大器的非线性失真，对其他涉及多个频率互调干扰的非线性失真都使用。
实施例二：
本实施例提供了一种数字预失真的装置，适用于超宽带多频段信号，如图2所示，包括：N个多维数字预失真模块、N个数字上变频模块、移频合路模块、多级频率选择模块、N个数字下变频模块和自适应算法模块；
每个频段位于零频的基带单/多载波CFR后信号XA-XN作为多维数字预失真DPDA-DPDN的输入信号。在预失真模块内部完成多维索引生成和查表操作，得到多频段基带预失真信号XdpdA-XdpdN。各频段基带预失真后信号经过数字上变频fA-上变频fN和移频合路，最终得到中频宽带多频段预失真信号Xdpd。
如图3所示，为图2中一个多维数字预失真模块A内部结构，包括：自索引生成模块、互索引生成模块；多维数字预失真A至多维数字预失真N的结构同理。从图3中可见，第K个频段DPDK(数字预失真)的实现不仅和该频段基带单/多载波信号Xk有关，还需要其它频段的信号Xj(j≠k)，每个频段所用的DPD查找表由多维索引完成，分别定义为自索引Pk、互索引Pj(j≠k)和整体索引Ps查找表结构的预失真实现方法为：
Xdpdk＝f(PA，PB，...PN，PS，Xk)＝LUT(P1，P2，...PN，PS)×Xk
由图2可知，对于一个N频段***，每个频段预失真查找表的维度为N+1。直接实现一个N+1维查找表的工作量巨大，查表过程也需要大量的运算。本发明在做自适应处理时，将模型中的N+1维索引拆分为N+1个1维索引，并将N+1个1维索引之和作为N+1维索引的简化结果。以双频段的预失真为例，设LSB表示下边带，HSB表示上边带，则简化形式的查找表实现的多维数字预失真可以表示为：
XdpdLSB＝
{LUTLL(PLSB(n)，PLSB(n-1)...，PLSB(n-kself))+LUTLH(PHSB(n)，PHSB(n-1)...，PHSB(n-kinter))+LUTLS(PS(n)，PS(n-1)...，PS(n-ksum))}×XLSB
XdpdHSB＝
{LUTHH(PHSB(n)，PHSB(n-1)...，PHSB(n-kself))+LUTHL(PLSB(n)，PLSB(n-1)...，PLSB(n-kinter))+LUTHS(PS(n)，PS(n-1)...，PS(n-ksum))}×XHSB
其中，LUTLL、LUTLH、LUTLS代表下边带拆分后的预失真多维查找表，LUTHH、LUTHL、LUTHS代表上边带拆分后的预失真多维查找表。PLSB、PHSB、PS分别代表索引生成模块计算的多维表格索引。kself代表自索引模型对应的记忆深度，kinter代表互索引模型对应的记忆深度，ksum代表整体索引对应的记忆深度。
图2中，自适应算法模块完成以下功能：采集预失真前各频段基带速率单载波或多载波CFR后信号XA-XN，以及中频宽带多频段非线性失真信号Y，作为自适应算法的训练数据。反馈训练数据首先经过多级频率选择算法分离出待拟合频段的中频反馈信号，再经过数字下变频fA-下变频fN得到和前向信号具有相同速率的基带反馈信号。自适应算法内部首先根据各频段前向信号的功率检测选择需要拟合预失真参数的频段，再对需要拟合预失真参数的频段进行自适应训练得到预失真系数，自适应算法包括但不限 于记忆多项式模型、非线性滤波器模型以及人工神经网络模型等，任意模型参数最终都将转换成查找表，更近到前向链路中以实现基带预失真功能。
如图4所示，为多级频率选择模块的内部结构示意图，对反馈的宽带多频段合路进行多级频率选择逐级分离出各频段的中频预失真信号；具体过程如下：
步骤1，获取***频段数控制字，确定频率选择算法的级数和算法参数；
步骤2，第K级频率选择开始，K＝1(对应最左侧频段)，输入宽带多频段信号；
步骤3，根据各频段频点信息进行移频，将频段K移到负频，其它频段移到正频；
步骤4，移频后信号IQ分离；
步骤5，分别对分离后的I路和Q路进行FFT变换，得到I′、Q′；
步骤6，取原始I路Q路和变换后的I′、Q′，进行信号IQ重组，得到正负频率分离的中频信号IF_1、IF_2；
步骤7，取正负频段分离的信号，负频率信号中心频点移至零频即为K频段数据；取正频率信号中心频点移至零频即为其它频段合路信号，完成第K级频率选择；
步骤8，如果K≤N-1，取K＝K+1重复步骤3-8，直到完成第N-1级频率选择，分离出所有频段信号。
实施例三：
本实施例描述了本发明方法应用于通信***发射链路双频段场景的具体过程，如图5所示，本实施例提供了一种数字预失真的***，包括：多维数字预失真模块、数字上变频模块、、移频合路模块、DAC模块、功放模块、耦合器、衰减器、ADC模块、其他数字处理算法、多级频率选择模块、数字下变频模块和自适应算法模块；具体预失真过程如下：
步骤1，双频段基带信号经过多维数字预失真模块DPD1和DPD2，得到双频段基带预失真信号。
步骤2，双频段预失真信号各自经过数字上变频得到高速预失真信号；
步骤3，双频段高速预失真信号经过移频合路，得到中频预失真合路信号；
步骤4，中频预失真信号经过数模转换DAC模块得到射频预失真信号；
步骤5，预失真信号经过功率放大器，得到线性校正后的功率放大信号；
步骤6，功率放大器发射信号耦合回来经过衰减器，得到宽带合路的反馈预失真训练数据；
步骤7，反馈预失真训练数据经过模数转换器ADC模块得到离散采样训练样本；
步骤8，经过其他中频数字预处理得到对齐后的前向和反馈训练数据；
步骤9，宽带合路反馈训练数据经过多级频率选择得到待拟合频段的中频信号；
步骤10，频率选择后的信号经过数字下变频得到基带反馈训练样本；
步骤11，预失真前向和反馈训练数据经过自适应训练，得到多维预失真表格。
步骤12，将多维预失真查找表新到前向链路预失真模块，完成预失真功能。
实施例四：
本发明数字预失真的方法可以适用于多频段预失真，也可以兼容单频段预失真功能，下面介绍数字预失真的方法中自适应过程即利用反馈数据更新预失真查找表的过程，如图6所示，包括：
步骤601，采集预失真训练样本；
本步骤中预失真训练样本为宽带合路的反馈预失真训练数据；
步骤602，进行其他中频数字信号处理；
步骤603，***配置参数获取，包括获取频段信息和频点信息等；
步骤604，根据***配置参数，判断是否需要多维预失真处理，如果需要多维预失真则继续步骤605，否则转入步骤609；
步骤605，多频段合路训练样本通过，多级频率选择模块逐级分离出各频段中频训练数据，
步骤606，各频段中频训练样本经过下变频和移频得到基带训练样本；
步骤607，各频段功率检测，根据各频段信号功率检测划分待拟合频段和不需要拟合频段；
步骤608，对待拟合频段生成多维索引，对不拟合频段进行查找表保持；
步骤609，预失真参数自适应参数提取。可以选择LS、LMS或其他自适应算法。
步骤610，预失真查找表生成。将所有频段预失真查找表综合；
步骤611，将预失真查找表更新到前向链路，完成自适应过程。
实施例五：
如图7所示，本实施例提供了一种数字预失真的装置，包括：数字预失真模块、数字上变频模块、移频合路模块、频率选择模块和更新模块；
所述数字预失真模块，用于通过查询对应的多维预失真查找表对各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；
所述数字上变频模块，用于分别对各频段的基带数字预失真信号进行数字上变频生成各频段中频数字预失真信号；
所述频率选择模块，用于对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；
所述更新模块，用于根据频段的失真反馈信号和预失真前所述频段的 基带信号更新所述频段对应的所述多维预失真查找表。
可选地，如图8所示，所述数字预失真模块包括：多个分别与宽带多频段信号频段对应的数字预失真子模块，所述数字上变频模块包括：多个分别与所述数字预失真子模块对应的数字上变频子模块；图8中包括n个数字预失真子模块和n个数字上变频子模块，n与宽带多频信号的频段数量对应；
所述数字预失真子模块，配置为通过查询自身存储的多维预失真查找表对与之对应的频段基带信号进行数字预失真处理，生成该频段的数字预失真信号；
所述数字上变频子模块，配置为对与之对应的数字预失真子模块传输的基带数字预失真信号进行数字上变频生成中频数字预失真信号。
可选地，如图9所示，本实施例的装置还可以包括：数字下变频模块；
所述数字下变频模块，配置为频率选择模块分离出各频段的失真反馈信号之后，所述更新模块更新多维预失真查找表之前，分别对各频段失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。
如图10所示，本实施例装置中所述更新模块包括：功率检测模块和自适应算法模块；
所述检测模块，配置为检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多维预失真查找表的频段；
所述自适应算法模块，配置为：
根据选取频段的失真反馈信号和预失真前的基带信号对所述选取频段进行自适应训练得到所述选取频段的多维预失真参数；
根据所述选取频段的多维预失真参数生成多维预失真查找表；
根据生成的多维预失真查找表更新所述选取频段对应的多维预失真查找表。
可选地，如图11所示，本实施例装置中，所述数字预失真子模块包括：索引生成模块、多维查找表模块和失真信号生成模块；
所述索引生成模块，配置为生成与所述数字预失真子模块对应的频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所有频段基带信号生成的整体索引；
所述多维查找表模块，配置为根据所述多维索引查询自身存储的多维预失真查找表；
所述失真信号生成模块，配置为根据所述多维查找表模块的查询结果和与所述数字预失真子模块对应的频段基带信号生成该频段的数字失真信号。
可选地，所述频率选择模块，配置为根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
本发明实施例还提供一种计算机存储介质，所述计算机存储介质中存储有计算机可执行指令，所述计算机可执行指令用于前述实施例所述数字预失真的方法的至少其中之一，具体如图1和/或图6所示的方法。
所述计算机存储介质可为光盘、移动硬盘、U盘、磁带等存储介质，可选为非瞬间存储介质。
以上内容是结合具体的实施方式对本发明所作的进一步详细说明，不能认定本发明的具体实施只局限于这些说明。凡按照本发明原理所作的修改，都应当理解为落入本发明的保护范围。

Claims (15)

  1. 一种数字预失真的方法，包括如下步骤：
    通过查询对应的多维预失真查找表对宽带多频段信号中各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；
    分别对各频段的数字预失真信号进行数字上变频生成各频段中频数字预失真信号；
    对各频段中频数字预失真信号进行移频合路生成宽带多频段合路预失真信号；
    对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；
    根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。
  2. 如权利要求1所述的方法，其中，在逐级分离出各频段的失真反馈信号之后，更新多维预失真查找表之前，所述方法还包括：
    分别对各频段的失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。
  3. 如权利要求2所述的方法，其中，所述根据频段失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表的步骤包括：
    选取需要更新多维预失真查找表的频段；
    根据选取频段的失真反馈信号和预失真前的基带信号更新所述选取频段对应的多维预失真查找表。
  4. 如权利要求3所述的方法，其中，所述选取需要更新多维预失真查找表的频段的步骤包括：
    检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多 维预失真查找表的频段。
  5. 如权利要求3所述的方法，其中，所述根据选取频段的失真反馈信号和预失真前的基带信号更新所述选取频段对应的多维预失真查找表的步骤包括：
    根据选取频段的失真反馈信号和预失真前的基带信号对所述选取频段进行自适应训练得到所述选取频段的多维预失真参数；
    根据所述选取频段的多维预失真参数生成多维预失真查找表；
    根据生成的多维预失真查找表更新所述选取频段对应的多维预失真查找表。
  6. 如权利要求1所述的方法，其中，所述通过查询对应的多维预失真查找表对各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号的步骤包括：
    生成各频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所有频段基带信号生成的整体索引；
    根据各频段基带信号的多维索引查询各频段对应的多维预失真查找表；
    根据各频段基带信号和各频段的查询结果生成各频段的数字预失真信号。
  7. 如权利要求1至6任一项所述的方法，其中，所述对所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号的步骤包括：
    根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
  8. 如权利要求7所述的方法，其中，所述根据频段数控制字和频点信 息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号的步骤包括：
    根据频段数控制字确定多级频率选择的级数；
    按照以下过程进行每一级频率选择直至分离出反馈的所述宽带多频段合路预失真信号中所有频段的失真反馈信号：
    根据反馈的所述宽带多频段合路预失真信号中各频段的频点信息进行移频，将与当前频率选择级数对应的频段移到负频、其他频段移到正频；
    对移频后的带宽多频合路预失真信号进行IQ正交分离；
    分别对分离后的I路预失真信号和Q路预失真信号进行FFT变换；
    对所述I路预失真信号、Q路预失真信号、FFT变换后的I路预失真信号、FFT变换后的Q路预失真信号进行IQ重组得到正频预失真信号和负频预失真信号；
    将所述负频预失真信号的中心频点移到零频得到与当前频率选择级数对应的频段的失真反馈信号，将所述正频预失真信号的中心频点移到零频。
  9. 一种数字预失真的装置，包括：数字预失真模块、数字上变频模块、移频合路模块、频率选择模块和更新模块；
    所述数字预失真模块，配置为通过查询对应的多维预失真查找表对各频段基带信号进行数字预失真处理，生成各频段的数字预失真信号；
    所述数字上变频模块，配置为分别对各频段的基带数字预失真信号进行数字上变频生成各频段中频数字预失真信号；
    所述频率选择模块，配置为对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号；
    所述更新模块，配置为根据频段的失真反馈信号和预失真前所述频段的基带信号更新所述频段对应的所述多维预失真查找表。
  10. 如权利要求9所述的装置，其中，
    所述数字预失真模块包括：多个分别与宽带多频段信号频段对应的数字预失真子模块，
    所述数字上变频模块包括：多个分别与所述数字预失真子模块对应的数字上变频子模块；
    所述数字预失真子模块，配置为通过查询自身存储的多维预失真查找表对与之对应的频段基带信号进行数字预失真处理，生成该频段的数字预失真信号；
    所述数字上变频子模块，配置为对与之对应的数字预失真子模块传输的基带数字预失真信号进行数字上变频生成中频数字预失真信号。
  11. 如权利要求9所述的装置，其中，还包括：数字下变频模块；
    所述数字下变频模块，配置为频率选择模块分离出各频段的失真反馈信号之后，所述更新模块更新多维预失真查找表之前，分别对各频段失真反馈信号进行数字下变频生成各频段的基带失真反馈信号。
  12. 如权利要求11所述的装置，其中，所述更新模块包括：功率检测模块和自适应算法模块；
    所述检测模块，配置为检测预失真前各频段基带信号的功率，根据检测结果选取需要更新多维预失真查找表的频段；
    所述自适应算法模块，配置为：
    根据选取频段的失真反馈信号和预失真前的基带信号对所述选取频段进行自适应训练得到所述选取频段的多维预失真参数；
    根据所述选取频段的多维预失真参数生成多维预失真查找表；
    根据生成的多维预失真查找表更新所述选取频段对应的多维预失真查找表。
  13. 如权利要求10所述的装置，其中，所述数字预失真子模块包括：索引生成模块、多维查找表模块和失真信号生成模块；
    所述索引生成模块，配置为生成与所述数字预失真子模块对应的频段基带信号的多维索引，所述多维索引包括：根据本频段基带信号生成的自索引、根据其他频段基带信号生成的互索引和根据所有频段基带信号生成的整体索引；
    所述多维查找表模块，配置为根据所述多维索引查询自身存储的多维预失真查找表；
    所述失真信号生成模块，配置为根据所述多维查找表模块的查询结果和与所述数字预失真子模块对应的频段基带信号生成该频段的数字失真信号。
  14. 如权利要求9至13任一项所述的装置，其中，
    所述频率选择模块，配置为根据频段数控制字和频点信息对反馈的所述宽带多频段合路预失真信号进行多级频率选择逐级分离出各频段的失真反馈信号。
  15. 一种计算机存储介质，所述计算机存储介质中存储有计算机可执行指令，所述计算机可执行指令用于执行权利要求1至8所述方法的至少其中之一。
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