WO2020220715A1 - 信号失真预校正方法、装置、系统及复合系统 - Google Patents

信号失真预校正方法、装置、系统及复合系统 Download PDF

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WO2020220715A1
WO2020220715A1 PCT/CN2019/130264 CN2019130264W WO2020220715A1 WO 2020220715 A1 WO2020220715 A1 WO 2020220715A1 CN 2019130264 W CN2019130264 W CN 2019130264W WO 2020220715 A1 WO2020220715 A1 WO 2020220715A1
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signal
correction
module
distortion
parameter
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PCT/CN2019/130264
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English (en)
French (fr)
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李运华
张哲远
杜文豪
宁东方
张作锋
戴征坚
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中兴通讯股份有限公司
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Priority to JP2021562395A priority Critical patent/JP7281558B2/ja
Priority to US17/607,303 priority patent/US20220224290A1/en
Priority to EP19927206.3A priority patent/EP3952109A4/en
Publication of WO2020220715A1 publication Critical patent/WO2020220715A1/zh

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    • 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
    • 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
    • H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
    • H03F1/0205—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
    • 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
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
    • H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
    • 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
    • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
    • 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
    • H03F3/245—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages with semiconductor devices only
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • 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
    • H03F2201/3215—To increase the output power or efficiency
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming

Definitions

  • the embodiments of the present disclosure relate to, but are not limited to, the field of communication technology, and in particular to a method, device, system, and composite system for signal distortion pre-correction.
  • MIMO Multiple In Multiple Out
  • a signal distortion pre-correction device including: a signal distortion correction network module, a correction parameter trainer, a data acquisition module, and a first conversion module.
  • the data acquisition module is connected to an external power amplifier module, wherein: data The acquisition module is configured to time-share the output signals of the multiple channels of the power amplifier module and output multiple analog feedback signals to the first conversion module; the first conversion module is configured to convert the multiple analog feedback signals into multiple And send the digital feedback signals to the correction parameter trainer; the correction parameter trainer is configured to determine correction parameters based on the multiple digital feedback signals and the input forward signal, and output the correction parameters to the signal distortion correction network module; and ,
  • the signal distortion correction network module is configured to output a pre-correction signal after correcting the forward signal based on the correction parameter.
  • Another aspect of the embodiments of the present disclosure provides a signal distortion pre-correction method, including: time-sharing collection of output signals of multiple channels of a power amplifier module to obtain multiple analog feedback signals; and converting the multiple analog feedback signals into A plurality of digital feedback signals; a correction parameter is determined according to the plurality of digital feedback signals and the input forward signal; and the forward signal is corrected based on the correction parameter to obtain a pre-correction signal.
  • a signal distortion pre-correction system including the signal distortion pre-correction device provided in the embodiments of the present disclosure, and further includes a second conversion module, an analog beamforming processor, and a power amplifier module, wherein:
  • the distortion pre-correction device is further configured to output the pre-correction signal to the second conversion module;
  • the second conversion module is configured to convert the pre-correction signal into an analog signal, and output the analog signal to the analog beamforming processor;
  • analog beamforming processing is configured to perform amplitude and phase weighting processing on the input analog signal to generate a weighted analog signal and output it to the power amplifier module; and, the power amplifier module is configured to amplify the weighted analog signal and output it .
  • Another aspect of the embodiments of the present disclosure provides a composite signal distortion pre-correction system, including multiple signal distortion pre-correction systems provided by the embodiments of the present disclosure, and the multiple signal distortion pre-correction systems multiplex the same correction parameter trainer
  • the correction parameter trainer is connected to the relevant modules in the multiple signal distortion pre-correction systems through at least one selection switch.
  • Fig. 1 is a structural diagram of a traditional signal distortion pre-device suitable for a MIMO millimeter wave communication system.
  • FIG. 2 is an architecture diagram of a signal distortion pre-correction device provided by an embodiment of the disclosure.
  • FIG. 3 is a diagram of another architecture of a signal distortion pre-correction device provided by an embodiment of the disclosure.
  • Fig. 4 is a basic structural diagram of a correction parameter trainer provided by an embodiment of the disclosure.
  • FIG. 5 is a basic structure diagram of a signal distortion correction network module provided by an embodiment of the disclosure.
  • FIG. 6 is another basic structure diagram of a signal distortion correction network module provided by an embodiment of the disclosure.
  • FIG. 7 is a flowchart of a signal distortion pre-correction method provided by an embodiment of the disclosure.
  • FIG. 8 is another flowchart of a signal distortion pre-correction method provided by an embodiment of the disclosure.
  • FIG. 9 is a schematic structural diagram of a composite system for signal distortion pre-correction provided by an embodiment of the disclosure.
  • FIG. 10 is a schematic diagram of another structure of a signal distortion pre-correction composite system provided by an embodiment of the disclosure.
  • Figure 1 is a structural diagram of a traditional signal distortion pre-distortion device suitable for MIMO millimeter wave communication systems.
  • the device includes: baseband signal 010, general DPD (Digital Pre-distortion, digital pre-distortion) (module) 011, DAC ( Digital to Analog Converter (module) 012, up-conversion (module) 013, analog beamforming (module) 014, power amplifier group 015, down-conversion (module) 016, ADC (Analog to Digital Converter, analog Digitizer) (module) 017 and data calibration processing (module) 018.
  • the device only performs feedback collection and data calibration processing on the output of one power amplifier, and extracts DPD parameters based on the general DPD architecture, and is used to correct and compensate the nonlinear distortion of all power amplifiers.
  • the feedback collection signals of multiple power amplifiers need to be de-beamed and combined in the analog domain, which is consistent with the characteristics of the power amplifier, and the transmission link between the output of each power amplifier and the combiner
  • the consistency requirements are very high; it is necessary to classify the output signals of all power amplifiers in the analog domain. If the classification standard is not selected properly, the performance of the signal distortion budget method will be greatly affected; and a power amplifier control module is required to control the performance of each power amplifier. Real-time adjustment of the supply voltage or current is not conducive to the stability of the power amplifier characteristics and will increase the system complexity.
  • the embodiments of the present disclosure provide a signal distortion pre-correction method and device suitable for a MIMO millimeter wave communication system.
  • the output signals of each power amplifier are collected in a time-sharing manner, and then multi-channel data parallel linear processing, the establishment of the correction model, and the signal matrix are performed.
  • the embodiment of the present disclosure provides a signal distortion pre-correction device, as shown in FIG. 2, which is an architecture diagram of the signal distortion pre-correction device provided in the embodiment of the disclosure.
  • the device may include: a signal distortion correction network module 100, The first conversion module 170, the correction parameter trainer 180, and the data collection module 190.
  • the device is connected to an external second conversion module 110, an analog beamforming processor 120, a power amplifier module 130 and an antenna array module (not shown in FIG. 2).
  • the antenna array module includes multiple antenna elements.
  • the data acquisition module 190 is connected to the power amplifier module 130.
  • the signal distortion correction network module 100 is connected to the second conversion module 110.
  • the second conversion module 110 is connected to the analog beamforming processor 120.
  • the power amplifier module 130 includes multiple One channel (analog channel), for example, one channel includes a power amplifier.
  • the data collection module 190 may be configured to collect the output signals of multiple channels of the power amplifier module 130 in a time-sharing manner, and output an analog feedback signal to the first conversion module 170.
  • the first conversion module 170 may be configured to convert the analog feedback signal into a digital feedback signal and send it to the correction parameter trainer 180; wherein, the first conversion module 170 is, for example, an analog-to-digital conversion module; in addition, the first conversion module 170 also It may have a frequency conversion function, such as an ADC with integrated frequency conversion function.
  • the correction parameter trainer 180 may be configured to determine correction parameters according to the digital feedback signal and the input forward signal, and output the correction parameters to the signal distortion correction network module 100. Specifically, the correction parameter trainer 180 can perform data linear processing on the forward signal and the digital feedback signal, and perform solution and iterative training on the signal distortion pre-correction model parameters.
  • the signal distortion pre-compensation model can be multiple sets of low-order filters, Volterra series, memory cross polynomials, neural networks (such as BP networks, ART networks, etc.), wavelet networks, support vector bases, and so on.
  • the signal distortion correction network module 100 may be configured to correct the input forward signal based on the correction parameters (or called distortion pre-compensation processing), and then output the pre-corrected signal to the second conversion module 110.
  • the signals of multiple channels can be collected in a time-sharing manner and corrected based on the feedback signals of the multiple channels, which has low requirements for the consistency of the characteristics of the power amplifiers of each channel in the system.
  • the data acquisition module 190 may include: a signal coupling network module 140 and a signal sampling controller 160, wherein the signal coupling network module 140 is connected to an external power amplifier module 130.
  • the signal sampling controller 160 may be configured to control the signal coupling network module 140 to implement time-sharing collection of output signals of multiple channels of the power amplifier module 130. Specifically, the control signal coupling network module 140 connects the output of a certain channel of the power amplifier module 130 with the feedback link to realize the collection of the output signal of the channel. It should be noted that the multiple channels collected by time sharing may include all channels of the power amplifier module 130, or may be part of all channels.
  • the signal coupling network module 140 can be configured to perform time-sharing coupling to the output signal of the channel of the power amplifier module 130 according to the control of the signal sampling controller 160, and output the analog feedback signal to the first conversion module 170; the output signal of each channel can be It is the output signal of each power amplifier of the power amplifier module.
  • the correction parameter trainer 180 may include a data linear processing module 181 and a correction parameter calculation module 182.
  • the data linear processing module 181 can be configured to perform linear processing on the forward signal and the digital feedback signal to obtain a linearly processed forward signal and a linearly processed digital feedback signal; wherein the linear processing includes but is not limited to at least one of the following : Delay alignment, image alignment, frequency alignment, feedback unevenness compensation, complex gain compensation.
  • the linear processing is parallel linear processing.
  • the correction parameter calculation module 182 can be configured to construct a plurality of signal matrices based on a preset signal distortion pre-correction model, linearly processed forward signals, linearly processed digital feedback signals, and pre-corrected signals.
  • the signal matrix and the collected There is a corresponding relationship between the channels; after the multiple signal matrices are respectively weighted with weighting factors, the weighted signal matrix is used to generate a combination matrix; the nonlinear distortion pre-compensation parameters are obtained based on the combination matrix; and the forward direction based on linear processing
  • the signal and the linearly processed digital feedback signal determine the link imbalance calibration parameters, and the weighting factor of the signal matrix is positively correlated with the performance of the channel corresponding to the signal matrix.
  • the weighting factor is the adjacent channel power ratio (Adjacent Channel Power Ratio, ACPR) of the channel corresponding to the signal matrix. It should be noted that the weighting factor is not limited to ACPR, and can also be obtained in other ways.
  • the constructed signal matrix is weighted to optimize the performance index in the beamforming direction; the feedback signal of each power amplifier is performed in parallel Linear processing can eliminate the effect of the delay, phase and amplitude difference of the coupled feedback link on the performance of the distortion correction algorithm; because the feedback signal of each power amplifier can be linearly processed, the beam angle is any angle when the correction parameters are extracted. It is not limited to the 0° beam, and can ensure the distortion pre-correction performance in the far-field beam direction.
  • the correction parameter calculation module 182 may be configured to determine the mismatch filter coefficient and the mutual coupling filter coefficient according to the power amplifier model of the power amplifier module, the linearly processed forward signal, and the linearly processed digital feedback signal; Based on the preset signal distortion pre-correction model, mismatch filter coefficients, mutual coupling filter coefficients, linearly processed forward signals, linearly processed digital feedback signals, and pre-corrected signals, multiple signal matrices are constructed.
  • Mismatch filter coefficient, mutual coupling filter coefficient, mismatch compensation parameters and mutual coupling compensation parameters can be used to correct the distortion caused by load mismatch and the distortion caused by mutual coupling interference between antennas, which can reduce the output load mismatch And the influence of mutual coupling interference between antennas on system performance.
  • mismatch filter coefficient, mutual coupling filter coefficient, mismatch compensation parameter, and mutual coupling compensation parameter may not be calculated.
  • the signal matrix corresponding to the j-th channel may be:
  • z j is a pre-correction signal
  • y 'j is a digital feedback signal after linear processing
  • h a is mismatched filter coefficients
  • h b is the mutual coupling of filter coefficients, L, Q, respectively, Is the memory depth and nonlinear order of the signal distortion pre-correction model
  • N+1 is the data length used to construct the signal matrix.
  • generating a combined matrix using the weighted signal matrix includes:
  • ⁇ 1 , ⁇ 2 ,..., ⁇ K are weighting factors.
  • FIG. 4 is a basic structural diagram of the correction parameter trainer 180 provided by an embodiment of the disclosure.
  • the correction parameter trainer 180 may include: a data linear processing module (not shown in FIG. 4) and a correction parameter calculation module 182.
  • the data linear processing module may include multiple parallel data linear processing sub-modules 181(1), 181(2), ... 181(K);
  • the correction parameter calculation module 182 may include a mismatch and mutual coupling coefficient estimation module 1821.
  • Matrix generation module (not shown in Figure 4), matrix weighting processing module 1823, and parameter estimation module 1824, wherein the matrix generation module may include multiple matrix generation sub-modules 1822(1), 1822(2),... .1822(K).
  • the mathematical expression of each power amplifier output signal is as follows:
  • y i (t) and x i (t) are the analog input signal and output signal of the i-th power amplifier respectively;
  • G[x i (t)] and ⁇ [x i (t)] are the i-th power amplifier respectively ⁇ i and ⁇ i are the frequency offset and transmission delay of the i-th analog channel, respectively.
  • the mismatch and mutual coupling coefficient estimation module 1821 may be configured to estimate the mismatch filter coefficient and the mutual coupling filter coefficient.
  • the mismatch filter coefficient is the coefficient used by the mismatch filter module for filtering
  • the mutual coupling filter coefficient is the coefficient used by the mutual coupling filter module for filtering.
  • y′ j f(x j ,x′ j ,x′′ j ),
  • j 1, 2, ..., K, f( ⁇ ) is a function describing the characteristics of the power amplifier; * is a linear convolution operator; x′ j is a standing wave signal fitted based on the forward signal; x′′ j based on the inter-forward signal and the interference fit of mutual coupling signal; h a mismatch of the filter coefficient; h b is the mutual coupling coefficient of the filter.
  • the power amplifier model can be selected according to the power amplifier characteristics in the power amplifier module, such as the memory cross polynomial model, of course, this is only an example, you can choose other power amplifier models as needed), select the forward after linear processing signal and the feedback signal (x j and y 'j), using a least squares algorithm (Least square, LS) of the model coefficients and mismatched filter coefficients and the mutual coupling of filter coefficients cross estimate, until meet the accuracy requirements of the coefficient h a and h b ; Then, select other groups of linearly processed data to perform the same operations as above to obtain multiple sets of mismatch filter coefficients and mutual coupling filter coefficients, and then average them to obtain the final mismatch filter coefficients and Mutual coupling filter coefficient.
  • LS least squares algorithm
  • the matrix generation module includes a plurality of matrix generation sub-modules 1822(1), 1822(2), ...
  • the matrix generation sub-module 1822(1) constructs signal matrices W 1 and V 1
  • matrix generation The sub-module 1822(2) constructs the signal matrices W 2 and V 2
  • the matrix generation sub-module 1822(K) constructs the signal matrices W K and V K ; the specific forms of the matrices W j and V j depend on the signal distortion used Pre-compensation model. If the memory polynomial model is adopted, the matrices W j and V j are:
  • L and Q are respectively the memory depth and nonlinear order of the signal distortion pre-compensation model
  • N+1 is the data length used to construct the signal matrix
  • the matrix weighting processing module 1823 can be configured to use weighting factors ⁇ 1 , ⁇ 2 ,..., ⁇ K to respectively perform matrix W 1 , W 2 ,..., W K and V 1 , V 2 ,... ,V K, after weighting, use the weighted matrix to generate the combined matrix W and V, namely:
  • the purpose of weighting the matrix is to ensure that the MIMO beamforming system can obtain better performance indicators in the far-field direction; among them, the weighting factors ⁇ 1 , ⁇ 2 ,..., ⁇ K and their corresponding channels
  • the performance is positively correlated, that is, the better the performance of the channel, the larger the weighting factor of the corresponding signal matrix.
  • a method for determining the weighting factor is as follows, the weighting factor ⁇ j of the signal matrix corresponding to the j-th channel is:
  • K is the number of channels (that is, the number of channels for time-sharing collection)
  • ACPR j is the adjacent channel power ratio of the j-th channel, which is calculated based on the j-th feedback signal y j ', that is, the signal of the main channel The ratio of the power to the signal power of the adjacent channel. It should be noted that the method of calculating the weighting factor is only an example, and other calculation methods can be used as needed.
  • the parameters include nonlinear distortion pre-compensation parameters, mismatch compensation parameters and mutual coupling compensation parameters; and the link imbalance calibration parameters are determined based on the linearly processed forward signal and the linearly processed feedback signal.
  • Link imbalance calibration parameters are used to eliminate IQ imbalance, local oscillator leakage and link unevenness.
  • the method of determining link imbalance calibration parameters can refer to related technologies.
  • the parameter solving iterative algorithm used includes but not limited to the following methods:
  • ⁇ and ⁇ are the adjustment factors of the iterative algorithm
  • c(n) is the parameter estimation value of the nth iteration
  • x(n) is the input signal of the distortion pre-correction model
  • ( ⁇ ) H is the total of the complex vector Yoke transposition operation
  • e(n) is the current fitting error value obtained by the pre-calibration model
  • h(n) is the weighting coefficient of the error signal e(n).
  • the signal distortion correction network module 100 may include: a first filter bank 101, a nonlinear distortion correction module 102, a link imbalance correction module 108, and a second filter bank 109.
  • the first filter bank 101 may be configured to perform rate conversion processing on the forward signal, and output the transformed forward signal to the nonlinear distortion correction module 102; the first filter bank 101 may include, for example, multiple finite impulse responses ( Finite Impulse Response (FIR) filter, which filters the forward signal x in parallel, and arranges the output signals s 1 , s 2 ,..., s M of each filter in chronological order to obtain the signal x a , thus completing Rate conversion processing of the forward signal x.
  • FIR Finite Impulse Response
  • the nonlinear distortion correction module 102 may be configured to correct the transformed forward signal according to the nonlinear distortion pre-compensation parameter in the correction parameters to generate a first correction signal and output the first correction signal to the link imbalance correction module 108. Specifically, the nonlinear distortion correction module 102 performs the construction of nonlinear basis functions on the output signal of the first filter bank 101 and the multiplication operation of each basis function and the nonlinear distortion pre-compensation parameters, thereby correcting the nonlinear characteristics introduced by the power amplifier. The signal is distorted.
  • An implementation manner is: using the output signal x a of the first filter bank 101 to construct nonlinear basis functions T 1 , T 2 , T 3 ,..., T N , where N is the number of nonlinear basis functions; Then, these nonlinear basis functions are multiplied by the corresponding model coefficients (ie, nonlinear distortion pre-compensation parameters) to obtain the first correction signal x d , which is used to offset the nonlinear signal distortion generated by the forward signal excitation power amplifier.
  • the specific presentation form of the nonlinear basis function depends on the signal distortion pre-compensation model used, which can be multiple sets of low-order filters, Volterra series, memory cross polynomials, neural networks (such as BP network , ART network, etc.), wavelet network and support vector basis, etc.; it should be noted that the signal distortion pre-compensation model may not be limited to the above models.
  • the link imbalance correction module 108 may be configured to process the first correction signal x d according to the link imbalance calibration parameter in the correction parameters, and output the fifth correction signal x h to the second filter bank 109; /Q imbalance, local oscillator leakage, and link unevenness correction processing.
  • the second filter bank 109 may be configured to perform rate conversion processing on the fifth correction signal x h to obtain a pre-correction signal, and output the pre-correction signal.
  • the second filter bank 109 may, for example, include multiple FIR filters, and perform parallel filtering processing on the signal x h to complete the rate conversion of the transmission signal to meet the rate requirement of the subsequent second conversion module 110.
  • the signal distortion correction network module 100 may include: a first filter bank 101, a nonlinear distortion correction module 102, a merging module 107, a link imbalance correction module 108, and a second filter bank 109.
  • the signal distortion correction network module 100 may also include a mismatch correction unit composed of a mismatch filter module 103 and a mismatch error compensation module 105, and a mutual coupling correction unit composed of a mutual coupling filter module 104 and a mutual coupling error compensation module 106.
  • the signal distortion correction network module 100 may only include the mismatch filter module 103 and the mismatch error compensation module 105, or may only include the mutual coupling filter module 104 and the mutual coupling error compensation module 106, or both include mismatch
  • the functions of the first filter bank 101, the nonlinear distortion correction module 102, and the second filter bank 109 can be referred to the foregoing content, which will not be repeated here. It should be noted that in this embodiment, the first correction signal output by the nonlinear distortion correction module 102 is not input to the link imbalance correction module 108, but is input to the merging module 107.
  • the mismatch filtering module 103 can be configured to filter the transformed forward signal (causal filtering or non-causal filtering) according to the mismatch filter coefficient in the correction parameter to generate the first intermediate signal x b , where x b is used for simulation
  • the standing wave signal generated by the load mismatch at the output end of the power amplifier module, and the first intermediate signal x b is output to the mismatch error compensation module 105; that is, the mismatch filter module 103 is used to simulate the output end load mismatch generated by the power amplifier module Standing wave signal.
  • the mismatch error compensation module 105 may be configured to correct the first intermediate signal x b according to the mismatch compensation parameter in the correction parameters to obtain the second correction signal x e , and output the second correction signal x e to the combining module 107. Specifically, the mismatch error compensation module 105 performs a nonlinear basis function construction on the output signal of the mismatch filter module and the first filter bank and the multiplication operation of each basis function and the mismatch filter coefficient, thereby correcting the load mismatch Signal distortion introduced.
  • the output signal of the first filter bank 101 and the output signal x a mismatched filtering module 103 x b, to construct the non-linear basis function S 1, S 2, S 3 , ..., S K, K is The number of nonlinear basis functions; then, these nonlinear basis functions are multiplied by the corresponding coefficients to obtain the error compensation signal x e ; the error compensation signal x e is used to offset the standing wave signal excitation power amplifier caused by the output load mismatch The resulting nonlinear signal is distorted.
  • the specific presentation form of the nonlinear basis function depends on the adopted mismatch error pre-compensation model, which can be multiple sets of low-order filters, Volterra series, memory cross polynomials, neural networks (such as BP network, ART network, etc.), wavelet network and support vector basis, etc.
  • the mismatch error pre-compensation model is not limited to the above-mentioned model.
  • the distortion caused by load mismatch can be corrected to reduce the impact of output load mismatch on system performance.
  • the mutual coupling filter module 104 may be configured to filter the transformed forward signal (causal filtering or non-causal filtering) according to the mutual coupling filter coefficient in the correction parameter to generate a second intermediate signal x c , where x c is used for simulation
  • the mutual coupling error compensation module 106 may be configured to correct the second intermediate signal x c according to the mutual coupling compensation parameter in the correction parameters to obtain the third correction signal x f , and output the third correction signal x f to the combining module 107.
  • the mutual coupling error compensation module 106 performs the construction of nonlinear basis functions on the output signals of the mutual coupling filter module 104 and the first filter bank 101 and the multiplication operation of each basis function and the mutual coupling filter coefficient, thereby correcting the antenna Signal distortion introduced by mutual coupling.
  • the output signal x a of the first filter bank 101 and the output signal x c of the mutual coupling filter module 104 are used to construct the nonlinear basis functions R 1 , R 2 , R 3 ,..., R M , M is the number of nonlinear basis functions; then, these nonlinear basis functions are multiplied by the corresponding coefficient values to obtain the mutual coupling error compensation signal x f ; the mutual coupling error compensation signal x f is used to offset the mutual coupling between antennas
  • the interference signal excites the nonlinear distortion produced by the power amplifier.
  • the specific presentation form of the nonlinear basis function depends on the mutual coupling error pre-compensation model used.
  • the mutual coupling error pre-compensation model can be multiple sets of low-order filters, Volterra series, memory cross polynomials, neural networks (such as BP network, ART network, etc.), wavelet network and support vector basis, etc. It should be noted that the mutual coupling error pre-compensation model may not be limited to the aforementioned model. According to the embodiments provided in the present disclosure, the distortion caused by mutual coupling interference between antennas is corrected, which can reduce the influence of mutual coupling interference between antennas on system performance.
  • the combining module 107 may be configured to combine the input signals to obtain a fourth correction signal x g , and output the fourth correction signal x g to the link imbalance correction module 108.
  • the input signal may be the first correction signal and the second correction signal, or the first correction signal and the third correction signal, or the first correction signal, the second correction signal, and the third correction signal.
  • the combination method is the addition of each input signal.
  • the link imbalance correction module 108 may be configured to process the fourth correction signal x g according to the link imbalance calibration parameter in the correction parameters, and output the fifth correction signal x h to the second filter bank 109. Specifically, the link imbalance correction module 108 performs filtering processing (linear processing) to correct I/Q imbalance, in-band unevenness, local oscillator leakage, etc. of the system transmission link.
  • filtering processing linear processing
  • the signal distortion correction network module 100 provided by the embodiments of the present disclosure, it is possible to correct the signal distortion introduced by nonlinear analog devices, output load mismatch and coupling interference between antennas.
  • a nonlinear system signal distortion pre-correction device For a MIMO millimeter wave communication system using analog beamforming technology, embodiments of the present disclosure provide a nonlinear system signal distortion pre-correction device.
  • a signal sampling controller is used to control the signal coupling network, collect and feed back the output signals of each power amplifier, and undergo multiple data linear processing operations, the calculation of mismatch factors and mutual coupling factors, and signal distortion pre-correction Model establishment and model parameter extraction can effectively precompensate the signal distortion of the MIMO system, and can cancel the mutual coupling interference between antennas; this can further ensure the performance advantages of the MIMO beamforming system.
  • this device can better solve the precompensation problem of nonlinear system signal distortion in the application scenario where one predistorter corresponds to multiple power amplifiers.
  • the signal distortion pre-correction device provided by the embodiment of the present disclosure has the following advantages.
  • the signal sampling controller controls the coupling network to collect and feedback the output signals of each power amplifier in a time-sharing manner, which has lower requirements for the consistency of the characteristics of each power amplifier in the system.
  • weighting the constructed signal matrix can make the performance index in the beamforming direction the best.
  • the beam angle is any angle when the correction parameters are extracted, not limited to the 0° beam, and the distortion pre-correction performance in the far field beam direction can be guaranteed.
  • the correction device provided by the embodiment of the present disclosure proposes a new signal distortion pre-correction algorithm, which can correct the overall nonlinear distortion of multiple parallel power amplifiers, and can also reduce Output load mismatch, coupling interference between antennas and other factors; it can use a feedback link channel to complete the time-sharing collection of the output signal of each channel.
  • the signal distortion pre-correction device provided by the embodiments of the present disclosure can be applied to wireless communication systems that use analog beamforming technology, such as millimeter wave communication systems, and can also be applied to communication systems where power amplifier characteristics are greatly affected by standing waves .
  • the input data signal (that is, the forward signal) can be either a service signal or a training sequence, and it has low requirements on the consistency of the characteristics of each power amplifier.
  • the feedback link selection switch in the signal coupling network module can be fixed to a certain channel, the feedback signal is collected and the subsequent operation processing is performed.
  • the embodiment of the present disclosure also provides a signal distortion pre-correction method, as shown in FIG. 7, which is a flowchart of the signal distortion pre-correction method provided by the embodiment of the present disclosure.
  • the method may include steps 701 to 704.
  • step 701 the output signals of multiple channels of the power amplifier module are time-divisionally collected to obtain multiple analog feedback signals.
  • step 702 the multiple analog feedback signals are converted into multiple digital feedback signals.
  • step 703 a correction parameter is determined according to the multiple digital feedback signals and the input forward signal.
  • step 704 the forward signal is corrected based on the correction parameter to obtain the pre-corrected signal.
  • the method may further include step 705.
  • step 705 the pre-correction signal is converted into an analog signal, and the analog signal is output to the analog beamforming processor.
  • determining the correction parameter based on the plurality of digital feedback signals and the input forward signal may include: linearly processing the forward signal and the digital feedback signal to obtain a linearly processed forward signal and linear processing After digital feedback signal; based on the preset signal distortion pre-correction model, the forward signal after linear processing, the digital feedback signal after linear processing and the pre-correction signal construct multiple signal matrices, where the signal matrix corresponds to the collected channel After the multiple signal matrices are respectively weighted using weighting factors, the weighted signal matrix is used to generate a combined matrix; the nonlinear distortion pre-compensation parameters, mismatch compensation parameters, and mutual coupling compensation parameters are obtained based on the combined matrix; and,
  • the link imbalance calibration parameter is determined based on the linearly processed forward signal and the linearly processed digital feedback signal, and the weighting factor of the signal matrix is positively correlated with the performance of the channel corresponding to the signal matrix.
  • the weighting factor ⁇ j of the signal matrix corresponding to the j-th channel is:
  • ⁇ max max ⁇ 1 , ⁇ 2 ,..., ⁇ K ⁇ ;
  • K is the number of channels
  • ACPR j is the ACPR of the j-th channel, that is, the ratio of the signal power of the adjacent channel of the j-th analog channel to the main channel.
  • determining the correction parameter according to the plurality of digital feedback signals and the input forward signal may include: linearly processing the input forward signal and the digital feedback signal to obtain the linearly processed forward signal and Digital feedback signal after linear processing; determine the mismatch filter coefficient and mutual coupling filter coefficient according to the power amplifier model of the power amplifier module, the forward signal after linear processing, and the digital feedback signal after linear processing; based on the signal distortion pre-correction model, mismatch Filter coefficients, mutual coupling filter coefficients, linearly processed forward signals, linearly processed digital feedback signals, and pre-correction signals construct multiple signal matrices, where the signal matrix has a corresponding relationship with the collected channels; and Multiple signal matrices are weighted using weighting factors, and the weighted signal matrix is used to generate a combination matrix.
  • nonlinear distortion pre-compensation parameters Based on the combination matrix, nonlinear distortion pre-compensation parameters, mismatch compensation parameters, and mutual coupling compensation parameters are obtained.
  • the signal matrix corresponding to the j-th channel is:
  • x j is a front after linear processing to the signal
  • z j is a pre-correction signal
  • y 'j is a digital feedback signal after linear processing
  • h a is mismatched filter coefficients
  • h b is the mutual coupling of filter coefficients
  • L is the memory depth and nonlinear order of the signal distortion pre-correction model respectively
  • N+1 is the data length used to construct the signal matrix.
  • correcting the input forward signal based on the correction parameter to obtain the pre-corrected signal may include: performing rate conversion processing on the forward signal to obtain the transformed forward signal;
  • the compensation parameter corrects the transformed forward signal to generate a first correction signal;
  • the first correction signal is processed according to the link imbalance calibration parameter in the correction parameters to obtain a fifth correction signal;
  • the fifth correction signal is rate
  • the transformation process obtains the pre-correction signal, and outputs the pre-correction signal.
  • correcting the input forward signal based on the correction parameter to obtain the pre-corrected signal may include: performing rate conversion processing on the forward signal to obtain the transformed forward signal; according to the nonlinear distortion in the correction parameter
  • the pre-compensation parameter corrects the transformed forward signal to generate a first correction signal; filters the transformed forward signal according to the mismatch filter coefficient in the correction parameter to generate the first intermediate signal, and compensates according to the mismatch in the correction parameter
  • the first intermediate signal is corrected by the parameter to obtain the second correction signal; the transformed forward signal is filtered according to the mutual coupling filter coefficient in the correction parameter to generate the second intermediate signal, and the second intermediate signal is generated according to the mutual coupling compensation parameter in the correction parameter.
  • the intermediate signal is corrected to obtain the third correction signal; the first correction signal and the second correction signal, or the first correction signal and the third correction signal, or the first correction signal, the second correction signal and the third correction signal are processed Combine to obtain a fourth correction signal; process the fourth correction signal according to the link imbalance calibration parameter in the correction parameters to generate a fifth correction signal; and perform rate conversion processing on the fifth correction signal to obtain a pre-correction signal, and output the pre-correction signal .
  • the embodiment of the present disclosure also provides a signal distortion pre-correction system.
  • the signal distortion pre-correction system may include the signal distortion pre-correction device provided in the embodiment of the present disclosure, a second conversion module 110, and analog beamforming processing. ⁇ 120 and power amplifier module 130.
  • the signal distortion pre-correction device may also be configured to output a pre-correction signal to the second conversion module 110.
  • the second conversion module 110 may be configured to convert the pre-correction signal into an analog signal and output it to the analog beamforming processor 120.
  • the analog beamforming processor 120 can be configured to perform amplitude and phase weighting processing on the input analog signal to generate the weighted analog signal and output it to the power amplifier module 130; this weighting processing facilitates the formation of the output signal of the subsequent antenna array A beam in a preset direction.
  • the power amplifier module 130 may be configured to amplify and output the weighted analog signal.
  • FIG. 8 it is another flow chart of the signal distortion pre-correction method provided by the embodiment of the present disclosure.
  • the method can be applied to the signal distortion pre-correction device provided in the embodiment of the present disclosure as shown in FIG. Step 801 to step 805 may be included.
  • step 801 the signal sampling controller 160 couples the network module 140 with the control signal, realizes time-sharing collection and feedback of the output signals of each power amplifier, and outputs the analog feedback signal to the first conversion module 170.
  • step 802 the first conversion module 170 converts the analog feedback signal into a digital feedback signal, and sends it to the correction parameter trainer 180.
  • the correction parameter trainer 180 obtains correction parameters according to the digital feedback signal and the input forward signal; the correction parameters may include: nonlinear distortion pre-compensation parameters, mismatch compensation parameters, mutual coupling compensation parameters, and link imbalance calibration parameter.
  • correction parameter trainer 180 may also obtain link imbalance calibration parameters according to the digital feedback signal and the input forward signal.
  • step 804 the correction parameters in the signal distortion correction network module 100 are updated in real time according to the correction parameter c provided by the correction parameter trainer 180; the signal distortion correction network module 100 is based on the forward signal x and its amplitude information, Perform nonlinear distortion and linear distortion pre-correction processing on signal x under the condition of high sampling rate, and send the obtained pre-corrected signal z to the second conversion module 110; the second conversion module 110 converts the pre-corrected signal (a digital signal) The analog signal is sent to the analog beamforming processor 120.
  • the analog beamforming processor 120 performs weighting processing on the phase and amplitude of the input signal and then outputs it.
  • the output signal of the analog beamforming processor 120 is amplified by the power amplifier of the power amplifier module 130 and then directly transmitted to The antenna array module 150 radiates into the space.
  • the analog beamforming processor 120 may use analog components such as an adjustable attenuator and a phase shifter to perform phase and amplitude weighting processing on the input signal.
  • the embodiment of the present disclosure also provides a composite system for signal distortion pre-correction.
  • FIG. 9 which is a schematic structural diagram of a signal distortion pre-correction composite system provided by an embodiment of the disclosure
  • the signal distortion pre-correction composite system may include multiple signal distortion pre-correction systems, and Multiple signal distortion pre-correction systems multiplex the same correction parameter trainer 180, and the correction parameter trainer 180 is connected to related modules in each signal distortion pre-correction system through a selection switch.
  • the correction parameter trainer 180 is connected to the input terminal of each signal distortion pre-correction system through the first selection switch 801, and is connected to the signal distortion correction network module 100 of each signal distortion pre-correction system through the second selection switch 802,
  • the three selection switch 803 is connected to the first conversion module 170 of each signal distortion pre-correction system.
  • FIG. 10 it is another structural schematic diagram of the signal distortion pre-correction composite system provided by the embodiments of the present disclosure.
  • the signal distortion pre-correction composite system can be applied to a MIMO millimeter wave communication system.
  • the numbers of digital channels and analog radio frequency channels are set to 4 and 32, respectively, and each digital channel corresponds to 8 analog radio frequency channels.
  • the output of 1 analog radio frequency channel is connected with 2 antenna elements.
  • the transmission signals of the 4 digital channels are 400MHz baseband signals containing 10 subcarriers, which are x a , x b , x c and x d respectively .
  • the following takes the signal transmission of digital channel 1 as an example to describe in detail the correction process of the signal distortion of the nonlinear system.
  • the signal transmission of the other digital channels is similar, and will not be repeated here.
  • the relevant signals of different digital channels are distinguished by subscripts a, b, c, and d.
  • the feedback VGA 200a is used to adjust the gain of the feedback signal y i (t) to ensure that the amplitude of the feedback signal is not too small to affect the extraction and training of distortion correction parameters.
  • step 1004 the correction parameter value c obtained by the correction parameter trainer 180 is copied to the signal distortion correction network module 100a through the selection switch Z, and the correction parameters in the signal distortion correction network module 100a are updated accordingly.
  • the analog radio frequency channel is transmitted, and the signal power becomes one-eighth;
  • the analog beamforming processor 120a uses the steering vector [ ⁇ 0 , ⁇ 1 e -j2 ⁇ d sin ⁇ ,..., ⁇ 7 e -j7*2 ⁇ d sin ⁇ ] weights the amplitude and phase of the RF transmission signal in the 8 analog channels to form a beam in a specific direction;
  • the power amplifier module 130a uses 8 parallel power amplifiers (130a1 ⁇ 130a8) for the analog beamforming processor 120a
  • the output signal of is amplified, directly transmitted to the antenna array module 150a and radiated into the space. It should be noted that ⁇ 0 , ⁇ 1 ,..., ⁇ 7 are the
  • the antenna array modules 150a, 150b, 150c, and 150d may each use 16 antenna elements, and the layout form is a 4*4 antenna area array; the 4 digital channels share a calibration parameter trainer 180.
  • the parameter trainer 180 is connected to the forward transmission link, signal distortion correction network and coupling feedback link of each digital channel through the selector switches X, Z, and Y, which can reduce the hardware resource requirements of the transmitter and greatly reduce The power consumption of the system.
  • Such software may be distributed on a computer-readable medium, and the computer-readable medium may include a computer storage medium (or a non-transitory medium) and a communication medium (or a transitory medium).
  • the term computer storage medium includes volatile and non-volatile memory implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Sexual, removable and non-removable media.
  • Computer storage media include but are not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage device, or Any other medium used to store desired information and that can be accessed by a computer.
  • communication media usually contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as carrier waves or other transmission mechanisms, and may include any information delivery media .

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Abstract

本公开提供一种信号失真预校正装置、方法、系统及复合系统。该信号失真预校正装置包括：信号失真校正网络模块、校正参数训练器、数据采集模块和第一转换模块，数据采集模块连接外部的功放模块，其中：数据采集模块，配置为对功放模块的多个通道的输出信号进行分时采集，并输出多个模拟反馈信号至第一转换模块；第一转换模块，配置为将该多个模拟反馈信号转换为多个数字反馈信号，并发送给校正参数训练器；校正参数训练器，配置为根据该多个数字反馈信号和输入的前向信号确定校正参数，并将校正参数输出给信号失真校正网络模块；以及，信号失真校正网络模块，配置为基于校正参数对所述前向信号进行校正后，输出预校正信号。

Description

信号失真预校正方法、装置、系统及复合系统 技术领域
本公开实施例涉及但不限于通信技术领域，尤其涉及一种信号失真预校正方法、装置、系统及复合系统。
背景技术
在现代移动通信系统中，多载波传输技术和高阶数字调制方式会导致系统的峰均比更高、信号传输带宽更大。当功率放大器(Power Amplifier，PA)工作在接近饱和区时，此种情况会导致PA产生严重的非线性失真和记忆效应。一种避免PA非线性失真的有效方法就是对输入信号的功率进行回退，但这会极大地降低PA的效率，也会增加其功耗。目前，数字预失真技术因具有代价较小、失真改善效果明显等优点，已成为非线性系统失真预校正的首选方法。
在第5代(5 th Generation，5G)毫米波通信中，为了获得更大的系统容量、更高的频谱利用率和更高的波束赋形增益，采用大规模多输入多输出(Massive Multiple In Multiple Out，Massive MIMO)技术和模拟波束赋形技术。而采用模拟波束赋形技术，会导致一个数字通道与多个模拟射频通道相连接。在此种情况下，若利用数字预失真技术，则需要设计一个预失真器对多个PA的非线性失真同时进行校正。而且在该系统中，因PA与天线阵子之间不存在环形器，则输出负载失配和天线间耦合干扰会对功放特性造成很大的影响，这也对预失真器的设计提出了更大的挑战。传统预失真算法较适用于一个数字通道对应一个模拟射频通道的场景。在多输入多输出(Multiple In Multiple Out，MIMO)模拟波束赋形系统中，若采用传统预失真方法，则会极大地增加发射机的结构复杂度和体积，也会增大其功耗。
发明内容
本公开实施例的一个方面提供一种信号失真预校正装置，包括：信号失真校正网络模块、校正参数训练器、数据采集模块和第一转换 模块，数据采集模块连接外部的功放模块，其中：数据采集模块，配置为对功放模块的多个通道的输出信号进行分时采集，并输出多个模拟反馈信号至第一转换模块；第一转换模块，配置为将该多个模拟反馈信号转换为多个数字反馈信号，并发送给校正参数训练器；校正参数训练器，配置为根据该多个数字反馈信号和输入的前向信号确定校正参数，并将校正参数输出给信号失真校正网络模块；以及，信号失真校正网络模块，配置为基于校正参数对前向信号进行校正后，输出预校正信号。
本公开实施例的另一个方面提供一种信号失真预校正方法，包括：对功放模块的多个通道的输出信号进行分时采集，获得多个模拟反馈信号；将该多个模拟反馈信号转换为多个数字反馈信号；根据该多个数字反馈信号和输入的前向信号确定校正参数；以及基于校正参数对前向信号进行校正得到预校正信号。
本公开实施例的又一个方面提供一种信号失真预校正系统，包括本公开实施例提供的信号失真预校正装置，还包括第二转换模块、模拟波束赋形处理器和功放模块，其中：信号失真预校正装置，还配置为输出预校正信号至第二转换模块；第二转换模块，配置为将预校正信号转换为模拟信号，输出模拟信号至模拟波束赋形处理器；模拟波束赋形处理器，配置为对输入的模拟信号进行幅度和相位的加权处理，生成加权处理后的模拟信号，并输出至功放模块；以及，功放模块，配置为对加权处理后的模拟信号进行放大处理后输出。
本公开实施例的再一个方面提供一种信号失真预校正复合系统，包括多个本公开实施例提供的信号失真预校正系统，且该多个信号失真预校正系统复用同一个校正参数训练器，校正参数训练器通过至少一个选择开关与该多个信号失真预校正系统中的相关模块相连。
附图说明
附图用来提供对本公开技术方案的进一步理解，并且构成说明书的一部分，与本公开的实施例一起用于解释本公开的技术方案，并不构成对本公开技术方案的限制。
图1为一种传统的适用于MIMO毫米波通信系统的信号失真预装置的架构图。
图2为本公开实施例提供的信号失真预校正装置的一种架构图。
图3为本公开实施例提供的信号失真预校正装置的一另种架构图。
图4为本公开实施例提供的校正参数训练器的一种基本结构图。
图5为本公开实施例提供的信号失真校正网络模块的一种基本结构图。
图6为本公开实施例提供的信号失真校正网络模块的另一种基本结构图。
图7为本公开实施例提供的信号失真预校正方法的一种流程图。
图8为本公开实施例提供的信号失真预校正方法的另一种流程图。
图9为本公开实施例提供的信号失真预校正复合系统的一种结构示意图。
图10为本公开实施例提供的信号失真预校正复合系统的另一种结构示意图。
具体实施方式
为使本公开的目的、技术方案和优点更加清楚明白，下文中将结合附图对本公开的实施例进行详细说明。需要说明的是，在不冲突的情况下，本公开中的实施例及实施例中的特征可以相互任意组合。
在附图的流程图示出的步骤可以在诸如一组计算机可执行指令的计算机系统中执行。并且，虽然在流程图中示出了逻辑顺序，但是在某些情况下，可以以不同于此处的顺序执行所示出或描述的步骤。
针对MIMO模拟波束赋形系统的失真预校正问题，业界也提出了一些解决方案。这些方案都可在一定程度上预校正多天线模拟波束赋形系统中的非线性信号失真，但存在很大的不足。
在一些情形下，只利用一个反馈链路通道对其中一路功放的输出信号进行采集反馈、数据预处理及模型参数提取，并用于对所有功 放的整体非线性失真进行校正，这对所有功放特性的一致性要求非常高。图1为一种传统的适用于MIMO毫米波通信系统的信号失真预装置的架构图，该装置包括：基带信号010、通用DPD(Digital Pre-distortion，数字预失真)(模块)011、DAC(Digital to Analog Converter，数字模拟转换器)(模块)012、上变频(模块)013、模拟波束赋形(模块)014、功放组015、下变频(模块)016、ADC(Analog to Digital Converter，模拟数字转换器)(模块)017和数据校准处理(模块)018。该装置只对一路功放的输出进行反馈采集以及数据校准处理，并基于通用DPD架构进行DPD参数的提取，且用于对所有功放的非线性失真进行校正及补偿。
在另一些情形下，需在模拟域中对多个功放的反馈采集信号进行去波束赋形处理并合路，这对功放特性的一致性、各个功放输出口到合路器之前的传输链路一致性要求非常高；需在模拟域中对所有功放的输出信号进行分类，若分类标准选择不恰当，则会极大地影响信号失真预算法的性能；而且需利用一个功放控制模块对各个功放的供电电压或电流进行实时调整，这不利于功放特性的稳定，且会增加系统复杂度。
此外，上述两种情形都没有考虑输出负载失配、天线耦合干扰等因素对信号失真预校正性能的影响。
本公开实施例提供一种适用于MIMO毫米波通信系统的信号失真预校正方法及装置，对各个功放的输出信号进行分时采集，然后进行多路数据并行线性处理、校正模型的建立、信号矩阵的构造及加权处理，并提取校正参数，最后对失真校正网路中的校正参数进行实时更新，从而达到对非线性系统失真进行预校正的目的。
本公开实施例提供一种信号失真预校正装置，如图2所示，其为本公开实施例提供的信号失真预校正装置的一种架构图，该装置可包括：信号失真校正网络模块100、第一转换模块170、校正参数训练器180和数据采集模块190。该装置与外部的第二转换模块110、模拟波束赋形处理器120、功放模块130和天线阵列模块(图2中未示出)相连。天线阵列模块包括多个天线阵子，数据采集模块190 连接功放模块130，信号失真校正网络模块100连接第二转换模块110，第二转换模块110连接模拟波束赋形处理器120，功放模块130包括多路通道(模拟通道)，一个通道比如包括一个功放。
数据采集模块190，可配置为对功放模块130的多个通道的输出信号进行分时采集，并输出模拟反馈信号至第一转换模块170。
第一转换模块170，可配置为将模拟反馈信号转换为数字反馈信号，并发送给校正参数训练器180；其中，第一转换模块170比如为模数转换模块；另外，第一转换模块170还可具有变频功能，比如为集成了变频功能的ADC。
校正参数训练器180，可配置为根据数字反馈信号和输入的前向信号确定校正参数，并将校正参数输出给信号失真校正网络模块100。具体的，校正参数训练器180可对前向信号和数字反馈信号进行数据线性处理，并对信号失真预校正模型参数进行求解及迭代训练。信号失真预补偿模型可以是多组低阶滤波器、Volterra级数、记忆交叉多项式、神经网络(如BP网络、ART网络等)、小波网络和支持向量基等等。
信号失真校正网络模块100，可配置为基于校正参数对输入的前向信号进行校正(或称失真预补偿处理)后，输出预校正信号至第二转换模块110。
根据本公开实施例提供的信号失真预校正装置，可分时采集多个通道的信号，并基于多通道的反馈信号进行校正，对系统中各个通道的功放的特性一致性要求较低。
在一示例性实施例中，如图3所示，其为本公开实施例提供的信号失真预校正装置的一另种架构图。数据采集模块190可包括：信号耦合网络模块140和信号取样控制器160，其中，信号耦合网络模块140连接外部的功放模块130。
信号取样控制器160，可配置为控制信号耦合网络模块140，实现对功放模块130的多个通道的输出信号的分时采集。具体地，控制信号耦合网络模块140使得功放模块130的某一通道的输出与反馈链路相连，实现对该通道的输出信号的采集。需要说明的是，分时采集 的多个通道可以包括功放模块130的全部通道，也可以是全部通道中的部分通道。
信号耦合网络模块140，可配置为根据信号取样控制器160的控制，对功放模块130的通道的输出信号进行分时耦合，并输出模拟反馈信号至第一转换模块170；各通道的输出信号可以是功放模块的各功放的输出信号。
在一示例性实施例中，校正参数训练器180可包括数据线性处理模块181和校正参数计算模块182。
数据线性处理模块181，可配置为对前向信号和数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；其中，线性处理包括但不限于以下至少之一：时延对齐、镜像校准、频点对齐、反馈不平坦度补偿、复增益补偿。在一示例性实施例中，线性处理为并行线性处理。
校正参数计算模块182，可配置为基于预设信号失真预校正模型、线性处理后的前向信号、线性处理后的数字反馈信号以及预校正信号构造多个信号矩阵，其中，信号矩阵与所采集的通道存在对应关系；将该多个信号矩阵分别使用加权因子进行加权处理后，使用加权后的信号矩阵生成组合矩阵；基于组合矩阵获取非线性失真预补偿参数；以及基于线性处理后的前向信号和线性处理后的数字反馈信号确定链路失衡校准参数，信号矩阵的加权因子与该信号矩阵对应的通道的性能正相关。在一示例性实施例中，加权因子为信号矩阵对应的通道的邻信道功率比(Adjacent Channel Power Ratio，ACPR)。需要说明的是，加权因子不限于ACPR，也可以通过其他方式得到。
根据本公开实施例提供的信号失真预校正装置，在校正参数提取过程中，对所构造信号矩阵进行加权处理，可使波束赋形方向上的性能指标最佳；对各个功放的反馈信号进行并行线性处理，可消除耦合反馈链路的时延、相位及幅度差异等对失真校正算法的性能影响；因可对各个功放的反馈信号进行线性处理，则在提取校正参数时波束角度为任意角，不局限于0°波束，且可保证远场波束方向上的失真预校正性能。
在一示例性实施例中，校正参数计算模块182，可配置为根据功放模块的功放模型、线性处理后的前向信号和线性处理后的数字反馈信号确定失配滤波系数和互耦滤波系数；基于预设信号失真预校正模型、失配滤波系数、互耦滤波系数、线性处理后的前向信号、线性处理后的数字反馈信号以及预校正信号构造多个信号矩阵，其中，信号矩阵与所采集的通道存在对应关系；将该多个信号矩阵分别使用加权因子进行加权处理后，使用加权后的信号矩阵生成组合矩阵；基于组合矩阵获取非线性失真预补偿参数、失配补偿参数、互耦补偿参数；以及，基于线性处理后的前向信号和线性处理后的数字反馈信号确定链路失衡校准参数，信号矩阵的加权因子与该信号矩阵对应的通道的性能正相关。失配滤波系数、互耦滤波系数、失配补偿参数和互耦补偿参数可用于进行对负载失配造成的失真进行校正和对天线间互耦干扰造成的失真进行校正，可减弱输出负载失配及天线间互耦干扰对系统性能的影响。
需要说明的是，在另一示例性实施例中，也可以不计算失配滤波系数、互耦滤波系数、失配补偿参数和互耦补偿参数。
在一示例性实施例中，第j个通道对应的信号矩阵可为：
Figure PCTCN2019130264-appb-000001
Figure PCTCN2019130264-appb-000002
其中，
Figure PCTCN2019130264-appb-000003
x j为线性处理后的前向信号，z j为预校正信号，y′ j为线性处理后的数字反馈信号，h a为失配滤波系数，h b为互耦滤波系数，L、Q分别为信号失真预校正模型的记忆深度和非线性阶数；N+1为构造信号矩阵所用的数据长度。
在一示例性实施例中，将该多个信号矩阵分别使用加权因子进 行加权处理后，使用加权后的信号矩阵生成组合矩阵包括：
Figure PCTCN2019130264-appb-000004
其中，α 1,α 2,....,α K为加权因子。
图4为本公开实施例提供的校正参数训练器180的一种基本结构图。校正参数训练器180可包括：数据线性处理模块(图4中未示出)和校正参数计算模块182。其中，数据线性处理模块可包括多个并行的数据线性处理子模块181(1)、181(2)、...181(K)；校正参数计算模块182可包括失配和互耦系数估计模块1821、矩阵生成模块(图4中未示出)、矩阵加权处理模块1823和参数估计模块1824，其中，矩阵生成模块可包括多个矩阵生成子模块1822(1)、1822(2)、...1822(K)。
数据线性处理子模块181(1)、181(2)、...181(K)基于前向信号x j(j＝1,2,...,K)，同时对各个功放输出的反馈信号y j并行地进行时延对齐、镜像校准、复增益补偿、频点对齐和反馈链路不平坦均衡等线性处理操作，从而得到线性处理后的反馈信号。各个功放输出信号的数学表达式如下：
Figure PCTCN2019130264-appb-000005
其中，y i(t)和x i(t)分别为第i个功放的模拟输入信号和输出信号；G[x i(t)]和Φ[x i(t)]分别为第i个功放的幅度失真和相位失真；ω i和τ i分别为第i个模拟通道的频率偏移和传输时延。因经链路传输后各个反馈信号的传输时延、幅度值和相位值不相同，且差别可能较大，则各路反馈信号分别进行线性处理可以消除传输链路间的差异，有利于后续校正模型参数的提取及训练。
失配和互耦系数估计模块1821，可配置为对失配滤波系数和互耦滤波系数进行估计。其中，失配滤波系数为失配滤波模块进行滤波时使用的系数，互耦滤波系数为互耦滤波模块进行滤波时使用的系数。
当考虑功放输出负载失配和天线间耦合干扰的影响时，前向信号和反馈信号之间的关系表达式如下所示：
y′ j＝f(x j,x′ j,x″ j)，
x′ j＝h a*x j,x″ j＝h b*x j；
式中，j＝1,2,…,K，f(·)为描述功放特性的函数；*为线性卷积运算符；x′ j为基于前向信号而拟合的驻波信号；x″ j为基于前向信号而拟合的天线间互耦干扰信号；h a为失配滤波系数；h b为互耦滤波系数。
根据具体的功放模型(功放模型可以根据功放模块中的功放特性进行选取，例如使用记忆交叉多项式模型，当然，此处仅为示例，可以根据需要选择其他功放模型)，选取线性处理之后的前向信号和反馈信号(x j和y′ j)，利用最小平方算法(Least Square，LS)对模型系数和失配滤波系数及互耦滤波系数进行交叉估计，直至获得满足精度要求的系数h a和h b；然后，选取其他多组的线性处理后数据进行上述相同的操作，得到多组失配滤波系数和互耦滤波系数，并对它们分别进行求平均运算，获得最终的失配滤波系数及互耦滤波系数。
矩阵生成模块，可配置为根据信号失真预校正模型，利用前向信号x j(j＝1,2，...，K)、反馈信号y j’(j＝1,2，...，K)、预校正信号z j(i＝1,2，...，K)、失配滤波系数h a及互耦滤波系数h b，并行构造信号矩阵为W 1,W 2,...,W K和V 1,V 2,...,V K。具体的，矩阵生成模块包括多个矩阵生成子模块1822(1)、1822(2)、...1822(K)，矩阵生成子模块1822(1)构造信号矩阵W 1和V 1，矩阵生成子模块1822(2)构造信号矩阵W 2和V 2，矩阵生成子模块1822(K)构造信号矩阵W K和V K；其中，矩阵W j和V j的具体形式取决于所采用的信号失真预补偿模型。若采用记忆多项式模型，则矩阵W j和V j为：
Figure PCTCN2019130264-appb-000006
Figure PCTCN2019130264-appb-000007
式中，
Figure PCTCN2019130264-appb-000008
L、Q分别为 信号失真预补偿模型的记忆深度和非线性阶数；N+1为构造信号矩阵所用的数据长度。
需要说明的是，上述W j和V j矩阵的构造仅为示例，可以根据需要采用其他方式构造。
在另一示例性实施例中，在不对负载失衡和互耦造成的非线性失真进行补偿时，
Figure PCTCN2019130264-appb-000009
矩阵加权处理模块1823，可配置为利用加权因子α 1,α 2,....,α K分别对矩阵W 1,W 2,...,W K和V 1,V 2,...,V K进行加权处理后，使用加权后的矩阵生成组合矩阵W和V，即：
Figure PCTCN2019130264-appb-000010
其中，对矩阵进行加权处理的目的是为了保证MIMO波束赋形系统能在远场方向获得较优的性能指标；其中，加权因子α 1,α 2,....,α K与其对应的通道的性能正相关，即通道的性能越好，其对应的信号矩阵的加权因子越大。
加权因子的一种确定方法如下，第j个通道对应的信号矩阵的加权因子α j为：
Figure PCTCN2019130264-appb-000011
Figure PCTCN2019130264-appb-000012
其中，K为通道数(即进行分时采集的通道数)，ACPR j为第j个通道的邻信道功率比，是根据第j路的反馈信号y j’计算出来的，即主信道的信号功率与邻信道的信号功率之比。需要说明的是，该计算加权因子的方法仅为示例，可以根据需要使用其他方式计算。
参数估计模块1824，可配置为基于矩阵W和V，V＝W*c，建立误差目标函数；采用参数求解方法进行校正参数提取，并进行多次迭代，得到最优的校正参数值c，校正参数包括非线性失真预补偿参数、失配补偿参数和互耦补偿参数；以及基于线性处理后的前向信号和线性处理后的反馈信号确定链路失衡校准参数。链路失衡校准参数用于消除IQ不平衡、本振泄露和链路的不平坦度，确定链路失衡校准参数的方法可参考相关技术。
其中，所采用的参数求解迭代算法包括但不限于下述方式：
Figure PCTCN2019130264-appb-000013
c(n)＝μ(n)·x(n)·e H(n)，
Figure PCTCN2019130264-appb-000014
上式中，μ、λ为迭代算法的调节因子；c(n)为第n次迭代的参数估计值；x(n)为失真预校正模型的输入信号；(·) H为复数矢量的共轭转置运算；e(n)为预校正模型所得当前时刻的拟合误差值；h(n)为误差信号e(n)的加权系数。
在一示例性实施例中，如图5所示，其为本公开实施例提供的信号失真校正网络模块100的一种基本结构图。信号失真校正网络模块100可包括：第一滤波器组101、非线性失真校正模块102、链路失衡校正模块108和第二滤波器组109。
第一滤波器组101，可配置为对前向信号进行速率变换处理，并输出变换后的前向信号至非线性失真校正模块102；第一滤波器组101比如可包括多个有限冲击响应(Finite Impulse Response，FIR)滤波器，并行对前向信号x进行滤波处理，并将各个滤波器的输出信号s 1,s 2,...,s M按时间顺序排列得到信号x a，从而完成前向信号x的速率变换处理。
非线性失真校正模块102，可配置为根据校正参数中的非线性失真预补偿参数对变换后的前向信号进行校正生成第一校正信号并输出第一校正信号至链路失衡校正模块108。具体地，非线性失真校正模块102对第一滤波器组101的输出信号进行非线性基函数的构造以及各基函数与非线性失真预补偿参数的相乘运算，从而校正由功放非线性特性引入的信号失真。一种实现方式为：利用第一滤波器组101的输出信号x a来构造非线性基函数T 1,T 2,T 3,...,T N，N为非线性基函数的个数；然后，这些非线性基函数与对应的模型系数(即非线性失真预补偿参数)相乘后得到第一校正信号x d，用于抵消由前向信号激励功放 所产生的非线性信号失真。其中，非线性基函数的具体呈现形式取决于所采用的信号失真预补偿模型，该信号失真预补偿模型可以是多组低阶滤波器、Volterra级数、记忆交叉多项式、神经网络(如BP网络、ART网络等)、小波网络和支持向量基等等；需要说明的是，信号失真预补偿模型也可不限于上述模型。
链路失衡校正模块108，可配置为根据校正参数中的链路失衡校准参数对第一校正信号x d进行处理，并输出第五校正信号x h至第二滤波器组109；以实现对I/Q不平衡、本振泄露、以及链路的不平坦度的校正处理。
第二滤波器组109，可配置为对第五校正信号x h进行速率变换处理得到预校正信号，并输出预校正信号。第二滤波器组109例如可包括多个FIR滤波器，对信号x h进行并行滤波处理，完成传输信号的速率变换，以满足后续第二转换模块110的速率要求。
在另一示例性实施例中，如图6所示，其为本公开实施例提供的信号失真校正网络模块100的另一种基本结构图。信号失真校正网络模块100可包括：第一滤波器组101、非线性失真校正模块102、合并模块107、链路失衡校正模块108和第二滤波器组109。信号失真校正网络模块100还可包括由失配滤波模块103和失配误差补偿模块105组成的失配校正单元、由互耦滤波模块104和互耦误差补偿模块106组成的互耦校正单元中的至少一个；即，信号失真校正网络模块100可以只包括失配滤波模块103和失配误差补偿模块105，也可以只包括互耦滤波模块104和互耦误差补偿模块106，或者，同时包括失配滤波模块103和失配误差补偿模块105，以及互耦滤波模块104和互耦误差补偿模块106；即信号失真校正网络模块100可以只进行失配校正，只进行互耦校正，或者，失配校正和互耦校正均进行。第一滤波器组101、非线性失真校正模块102和第二滤波器组109的功能可参考前述内容，此处不再赘述。需要说明的是，在本实施例中，非线性失真校正模块102输出的第一校正信号不输入到链路失衡校正模块108，而是输入到合并模块107。
失配滤波模块103，可配置为根据校正参数中的失配滤波系数对 变换后的前向信号进行滤波(因果滤波或者非因果滤波)生成第一中间信号x b，其中，x b用于模拟功放模块的输出端负载失配所产生的驻波信号，以及输出第一中间信号x b至失配误差补偿模块105；即失配滤波模块103用于模拟功放模块的输出端负载失配所产生的驻波信号。
失配误差补偿模块105，可配置为根据校正参数中的失配补偿参数对第一中间信号x b进行校正得到第二校正信号x e，以及输出第二校正信号x e至合并模块107。具体地，失配误差补偿模块105对失配滤波模块和第一滤波器组的输出信号进行非线性基函数的构造以及各基函数与失配滤波系数的相乘运算，从而校正由负载失配引入的信号失真。首先，利用第一滤波器组101的输出信号x a和失配滤波模块103的输出信号x b，来构造非线性基函数S 1,S 2,S 3,...,S K，K为非线性基函数的个数；然后，将这些非线性基函数与对应的系数相乘后得到误差补偿信号x e；误差补偿信号x e用于抵消由输出负载失配导致的驻波信号激励功放所产生的非线性信号失真。其中，非线性基函数的具体呈现形式取决于所采用的失配误差预补偿模型，该失配误差预补偿模型可以是多组低阶滤波器、Volterra级数、记忆交叉多项式、神经网络(如BP网络、ART网络等)、小波网络和支持向量基等等。需要说明的是，失配误差预补偿模型不限于上述模型。根据本公开提供的实施例，对负载失配造成的失真进行校正，可减弱输出负载失配对系统性能的影响。
互耦滤波模块104，可配置为根据校正参数中的互耦滤波系数对变换后的前向信号进行滤波(因果滤波或者非因果滤波)生成第二中间信号x c，其中，x c用于模拟功放模块的输出端天线间的互耦干扰信号；并输出第二中间信号x c至互耦误差补偿模块106；即该互耦滤波模块104可用于模拟功放模块的输出端天线间的互耦干扰信号。
互耦误差补偿模块106，可配置为根据校正参数中的互耦补偿参数对第二中间信号x c进行校正得到第三校正信号x f，并输出第三校正信号x f至合并模块107。具体地，互耦误差补偿模块106对互耦滤波模块104和第一滤波器组101的输出信号进行非线性基函数的构造以及各基函数与互耦滤波系数的相乘运算，从而校正由天线间互相耦合引 入的信号失真。具体地，首先利用第一滤波器组101的输出信号x a和互耦滤波模块104的输出信号x c，来构造非线性基函数R 1,R 2,R 3,...,R M，M为非线性基函数的个数；然后，将这些非线性基函数与对应的系数值相乘后得到互耦误差补偿信号x f；互耦误差补偿信号x f用于抵消由天线间互耦干扰信号激励功放所产生的非线性失真。其中，非线性基函数的具体呈现形式取决于所采用的互耦误差预补偿模型，该互耦误差预补偿模型可以是多组低阶滤波器、Volterra级数、记忆交叉多项式、神经网络(如BP网络、ART网络等)、小波网络和支持向量基等等。需要说明的是，互耦误差预补偿模型可不限于上述模型。根据本公开提供的实施例，对天线间互耦干扰造成的失真进行校正，可减弱天线间互耦干扰对系统性能的影响。
合并模块107，可配置为对输入信号进行合并得到第四校正信号x g，并输出第四校正信号x g至链路失衡校正模块108。其中，输入信号可能是第一校正信号和第二校正信号，也可能是第一校正信号和第三校正信号，也可能是第一校正信号、第二校正信号和第三校正信号。合并方式为各输入信号相加。
链路失衡校正模块108，可配置为根据校正参数中的链路失衡校准参数对第四校正信号x g进行处理，并输出第五校正信号x h至第二滤波器组109。具体地，链路失衡校正模块108进行滤波处理(线性处理)，以校正系统发射链路的I/Q不平衡、带内不平坦度、本振泄露等。
根据本公开实施例提供的信号失真校正网络模块100，可以实现校正由非线性模拟器件、输出负载失配及天线间耦合干扰而引入的信号失真。
针对采用模拟波束赋形技术的MIMO毫米波通信系统，本公开实施例提供了一种非线性系统信号失真预校正装置。在该校正装置中，利用信号取样控制器对信号耦合网络进行控制，收集并反馈各路功放的输出信号，经过多路数据线性处理操作、失配因子与互耦因子的计算、信号失真预校正模型建立、模型参数的提取，有效地对MIMO系统的信号失真进行预补偿，并可对天线间互耦干扰进行抵消处理；这样可进一步保证MIMO波束赋形系统的性能优势发挥。与传统预失真 技术相比，该装置可较好地解决一个预失真器对应多个功放的应用场景中非线性系统信号失真的预补偿问题。
本公开实施例提供的信号失真预校正装置具有以下优势。
1)信号取样控制器控制耦合网络可对各个功放的输出信号进行分时采集反馈，这对系统中各个功放的特性一致性要求较低。
2)在校正参数提取过程中，对所构造信号矩阵进行加权处理，可使波束赋形方向上的性能指标最佳。
3)对各个功放的反馈信号进行并行线性处理，可消除耦合反馈链路的时延、相位及幅度差异等对失真校正算法的性能影响。
4)因可对各个功放的反馈信号进行线性处理，则在提取校正参数时波束角度为任意角，不局限于0°波束，且可保证远场波束方向上的失真预校正性能。
5)可减弱输出负载失配及天线间互耦干扰对系统性能的影响。
与相关技术中的失真校正装置相比，本公开实施例提供的校正装置提出了一种新的信号失真预校正算法，可实现对多个并行功放的整体非线性失真的校正，同时也可减弱输出负载失配、天线间耦合干扰等因素的影响；它可采用一条反馈链路通道，完成各个通道输出信号的分时采集。本公开实施例提供的信号失真预校正装置，既可应用于采用模拟波束赋形技术的无线通信系统中，例如毫米波通信系统，也可应用在功放特性受驻波影响较大的通信系统中。
根据本公开实施例提供的信号失真预校正装置，其输入的数据信号(即前向信号)既可以是业务信号又可以是训练序列，且其对各路功放特性的一致性要求较低。而且当各路功放特性的一致性较好时，可将信号耦合网络模块中的反馈链路选择开关固定到某一个通道上，采集反馈信号并进行后续的操作处理。
本公开实施例还提供一种信号失真预校正方法，如图7所示，其为本公开实施例提供的信号失真预校正方法的一种流程图，该方法可包括步骤701～步骤704。
在步骤701中，对功放模块的多个通道的输出信号进行分时采集，获得多个模拟反馈信号。
在步骤702中，将多个模拟反馈信号转换为多个数字反馈信号。
在步骤703中，根据该多个数字反馈信号和输入的前向信号确定校正参数。
在步骤704中，基于校正参数对前向信号进行校正得到预校正信号。
在另一示例性实施例中，该方法还可包括步骤705。
在步骤705中，将预校正信号转换为模拟信号，输出模拟信号至模拟波束赋形处理器。
在一示例性实施例中，根据该多个数字反馈信号和输入的前向信号确定校正参数可包括：对前向信号和数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；基于预设信号失真预校正模型，线性处理后的前向信号、线性处理后的数字反馈信号以及预校正信号构造多个信号矩阵，其中，信号矩阵与所采集的通道对应；将该多个信号矩阵分别使用加权因子进行加权处理后，使用加权处理后的信号矩阵生成组合矩阵；基于组合矩阵获取非线性失真预补偿参数、失配补偿参数以及互耦补偿参数；以及，基于线性处理后的前向信号和线性处理后的数字反馈信号确定链路失衡校准参数，信号矩阵的加权因子与该信号矩阵对应的通道的性能正相关。
在一示例性实施例中，第j个通道对应的信号矩阵的加权因子α j为：
Figure PCTCN2019130264-appb-000015
Figure PCTCN2019130264-appb-000016
γ max＝max{γ 1,γ 2,....,γ K}；
其中，K为通道数，ACPR j是第j个通道的ACPR，即第j个模拟通道的邻信道与主信道的信号功率之比。
在一示例性实施例中，根据该多个数字反馈信号和输入的前向信号确定校正参数可包括：对输入的前向信号和数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；根据功放模块的功放模型、线性处理后的前向信号和线性处理后的数字反馈信号确定失配滤波系数和互耦滤波系数；基于信号失真预校正模 型、失配滤波系数、互耦滤波系数、线性处理后的前向信号、线性处理后的数字反馈信号以及预校正信号构造多个信号矩阵，其中，信号矩阵与所采集的通道存在对应关系；以及，将该多个信号矩阵分别使用加权因子进行加权处理，使用加权处理后的信号矩阵生成组合矩阵，基于组合矩阵获取非线性失真预补偿参数、失配补偿参数以及互耦补偿参数，基于线性处理后的前向信号和线性处理后的数字反馈信号确定链路失衡校准参数，信号矩阵的加权因子与该信号矩阵对应的通道的性能正相关。
在一示例性实施例中，第j个通道对应的信号矩阵为：
Figure PCTCN2019130264-appb-000017
Figure PCTCN2019130264-appb-000018
其中，
Figure PCTCN2019130264-appb-000019
其中，x j为线性处理后的前向信号，z j为预校正信号，y′ j为线性处理后的数字反馈信号，h a为失配滤波系数，h b为互耦滤波系数，L、Q分别为信号失真预校正模型的记忆深度和非线性阶数；N+1为构造信号矩阵所用的数据长度。
在一示例性实施例中，基于校正参数对输入的前向信号进行校正得到预校正信号可包括：对前向信号进行速率变换处理得到变换后的前向信号；根据校正参数中非线性失真预补偿参数对变换后的前向信号进行校正生成第一校正信号；根据校正参数中的链路失衡校准参数对第一校正信号进行处理，得到第五校正信号；以及，对第五校正信号进行速率变换处理得到预校正信号，输出预校正信号。
在一示例性实施例中，基于校正参数对输入的前向信号进行校正得到预校正信号可包括：对前向信号进行速率变换处理得到变换后的前向信号；根据校正参数中的非线性失真预补偿参数对变换后的前 向信号进行校正生成第一校正信号；根据校正参数中的失配滤波系数对变换后的前向信号进行滤波生成第一中间信号，根据校正参数中的失配补偿参数对第一中间信号进行校正得到第二校正信号；根据校正参数中的互耦滤波系数对变换后的前向信号进行滤波生成第二中间信号，根据校正参数中的互耦补偿参数对第二中间信号进行校正得到第三校正信号；将第一校正信号和第二校正信号，或者，第一校正信号和第三校正信号，或者，第一校正信号、第二校正信号和第三校正信号进行合并得到第四校正信号；根据校正参数中的链路失衡校准参数对第四校正信号进行处理生成第五校正信号；以及，对第五校正信号进行速率变换处理得到预校正信号，输出预校正信号。
本公开实施例还提供一种信号失真预校正系统，参考图2，该信号失真预校正系统可包括本公开实施例提供的信号失真预校正装置，以及第二转换模块110、模拟波束赋形处理器120和功放模块130。
信号失真预校正装置，还可配置为输出预校正信号至第二转换模块110。
第二转换模块110，可配置为将预校正信号转换为模拟信号，并输出至模拟波束赋形处理器120。
模拟波束赋形处理器120，可配置为对输入的模拟信号进行幅度和相位的加权处理，生成加权处理后的模拟信号并输出至功放模块130；该加权处理是便于后续天线阵列的输出信号形成预设方向的波束。
功放模块130，可配置为对加权处理后的模拟信号进行放大处理后输出。
下面结合附图和5G毫米波通信系统的应用场景，对本公开实施例提供的信号失真预校正装置以及方法进行详细描述。
如图8所示，其为本公开实施例提供信号失真预校正方法的另一种流程图，该方法可应用于如图3所示的本公开实施例提供的信号失真预校正装置，该方法可包括步骤801～步骤805。
在步骤801中，信号取样控制器160通过控制信号耦合网络模块140，实现对各个功放输出信号的分时采集反馈，并输出模拟反馈 信号至第一转换模块170。
在步骤802中，第一转换模块170将模拟反馈信号转换为数字反馈信号，并发送给校正参数训练器180。
在步骤803中，校正参数训练器180根据数字反馈信号和输入的前向信号获得校正参数；校正参数可包括：非线性失真预补偿参数、失配补偿参数、互耦补偿参数和链路失衡校准参数。
具体地，校正参数训练器180首先基于前向信号x＝[x 1,x 2,...,x K]，对第一转换模块170的输出信号y＝[y 1,y 2,...,y K]进行多路数据线性处理操作，得到预处理后信号；然后，利用所得的预处理后信号对失配滤波系数和互耦滤波系数进行求解；最后，构造信号失真校正模型的目标函数，并利用参数求解迭代算法获得最终的校正参数c，其中，K为进行分时采集的通道数量，一个通道包括一个功放时，即为并行功放的个数。需要说明的是，K小于等于功放模块130的通道的数量。
另外，校正参数训练器180还可根据数字反馈信号和输入的前向信号获得链路失衡校准参数。
在步骤804中，根据校正参数训练器180所提供的校正参数c，对信号失真校正网络模块100中的校正参数进行实时更新；信号失真校正网络模块100根据前向信号x及其幅值信息，在高采样速率条件下对信号x进行非线性失真和线性失真的预校正处理，将所得预校正信号z发送给第二转换模块110；第二转换模块110将预校正信号(为数字信号)转换为模拟信号发送给模拟波束赋形处理器120。
在步骤805中，模拟波束赋形处理器120对输入信号的相位与幅度进行加权处理后输出，模拟波束赋形处理器120的输出信号经过功放模块130的功率放大器的放大处理后，直接传送到天线阵列模块150并辐射到空间中。其中，模拟波束赋形处理器120可以利用可调衰减器、相位偏移器等模拟器件对输入信号进行相位与幅度的加权处理。
本公开实施例还提供一种信号失真预校正复合系统。如图9所示，其为图9为本公开实施例提供的一种信号失真预校正复合系统的一种结构示意图，该信号失真预校正复合系统可包括多个信号失真预 校正系统，且该多个信号失真预校正系统复用同一校正参数训练器180，校正参数训练器180通过选择开关与各信号失真预校正系统中的相关模块相连。具体地，校正参数训练器180通过第一选择开关801与各信号失真预校正系统的输入端相连，通过第二选择开关802与各信号失真预校正系统的信号失真校正网络模块100相连，通过第三选择开关803与各信号失真预校正系统的第一转换模块170相连。
如图10所示，其为本公开实施例提供的信号失真预校正复合系统的另一种结构示意图，该信号失真预校正复合系统可适用于MIMO毫米波通信系统。
在一示例性实施例中，在采用模拟赋形技术的MIMO下行传输系统中，设定数字通道和模拟射频通道的个数分别为4和32，每1个数字通道对应8个模拟射频通道，1个模拟射频通道的输出与2个天线阵子相连。同时假设4个数字通道的发送信号都为含有10个子载波的400MHz基带信号，分别为x a、x b、x c与x d。
下面以数字通道1的信号发送为例，详细说明非线性系统信号失真的校正过程。其余数字通道的信号发送类似，此处不再赘述。不同数字通道的相关信号以下标a，b，c，d进行区分。
在步骤1001中，信号取样控制器160a通过控制信号耦合网络模块140a，实现对各个功放输出信号的分时采集，得到反馈信号y i(t)，(i＝1,2,...,8)，同时，利用反馈VGA 200a对反馈信号y i(t)的增益大小进行调整，保证反馈信号的幅值不至于过小而影响失真校正参数的提取及训练。
在步骤1002中，210a模块产生频率为fr＝27GHz的本地振荡信号，将射频信号y i(t)搬移至零中频，并经过ADC模块170a后输出数字反馈信号y a＝[y 1,y 2,...,y 8]。
在步骤1003中，校正参数训练器180通过选择开环X、Y分别与数字通道1的前向链路及反馈链路相连后，首先分别对前向信号x i和反馈采集信号y i(i＝1,2,...,8)进行时延对齐、镜像校准、复增益补偿等数据线性处理操作，得到预处理后的信号y i’(i＝1,2,...,8)；然后，基于功放模型，利用前向信号x i对信号y i’进行逼近拟合，采用LS方 法计算出失配滤波系数h a和互耦滤波系数h b的估计值；其次，根据所采用的信号失真预校正模型构造信号矩阵W 1,W 2,...,W 8和V 1,V 2,...,V 8，确定加权因子α 1,α 2,…,α 8的值的大小，并对所构造矩阵进行加权处理得到复合矩阵W和V；最后，使用迭代方法对失真预校正参数进行多次迭代计算，得到校正参数的最优值c。
在步骤1004中，通过选择开关Z将校正参数训练器180所得的校正参数值c复制给信号失真校正网络模块100a，并对信号失真校正网络模块100a中的校正参数进行相应更新。
在步骤1005中，根据数字通道1上发送的400MHz基带信号x a＝[x 1,x 2,...,x K]及其幅值，信号失真校正网络模块100a在高采样速率条件下进行失配和互耦滤波处理，构造非线性基函数，并与相应的校正参数相乘，从而完成对前向信号x a的失真预补偿处理操作，得到预校正信号z a，该信号经DAC(模块)110a处理后转换成模拟信号。
在步骤1006中，210a模块提供频率为f r＝27GHz的本地振荡信号，将DAC(模块)110a的输出信号搬移到射频端；射频发送信号经过功分器组190a处理后，并行地在8个模拟射频通道上传输，且信号功率变为原来的八分之一；模拟波束赋形处理器120a利用导向矢量[β 0,β 1e -j2πd sinθ,...,β 7e -j7*2πd sinθ]对8个模拟通道中射频传输信号的幅度及相位进行加权处理，以便于形成特定方向的波束；而功放模块130a采用并行的8个功放(130a1～130a8)对模拟波束赋形处理器120a的输出信号进行放大处理，直接传输到天线阵列模块150a并辐射到空间中。需要说明的是，β 0,β 1,...,β 7为各个模拟射频通道上的信号幅度加权值，d为天线阵子间的距离，θ为波束方向夹角。
在一示例性实施例中，天线阵列模块150a、150b、150c及150d可均采用16个天线阵子，布局形式为4*4天线面阵；4个数字通道共用一个校正参数训练器180，该校正参数训练器180通过选择开关X、Z、Y分别与各个数字通道的前向发射链路、信号失真校正网络及耦合反馈链路相连，既可减少发射机的硬件资源需求，也可极大地降低系统的功耗。
提供本公开实施例的详细描述的目的是为了使研究本领域的技术 人员能够制造或使用本公开。本公开实施例的各种修改对于本领域的技术人员来说是易理解的。
本领域普通技术人员可以理解，上文中所公开方法中的全部或某些步骤、系统、装置中的功能模块/单元可以被实施为软件、固件、硬件及其适当的组合。在硬件实施方式中，在以上描述中提及的功能模块/单元之间的划分不一定对应于物理组件的划分；例如，一个物理组件可以具有多个功能，或者一个功能或步骤可以由若干物理组件合作执行。某些组件或所有组件可以被实施为由处理器，如数字信号处理器或微处理器执行的软件，或者被实施为硬件，或者被实施为集成电路，如专用集成电路。这样的软件可以分布在计算机可读介质上，计算机可读介质可以包括计算机存储介质(或非暂时性介质)和通信介质(或暂时性介质)。如本领域普通技术人员公知的，术语计算机存储介质包括在用于存储信息(诸如计算机可读指令、数据结构、程序模块或其他数据)的任何方法或技术中实施的易失性和非易失性、可移除和不可移除介质。计算机存储介质包括但不限于RAM、ROM、EEPROM、闪存或其他存储器技术、CD-ROM、数字多功能盘(DVD)或其他光盘存储、磁盒、磁带、磁盘存储或其他磁存储装置、或者可以用于存储期望的信息并且可以被计算机访问的任何其他的介质。此外，本领域普通技术人员公知的是，通信介质通常包含计算机可读指令、数据结构、程序模块或者诸如载波或其他传输机制之类的调制数据信号中的其他数据，并且可包括任何信息递送介质。

Claims (17)

  1. 一种信号失真预校正装置，包括：信号失真校正网络模块、校正参数训练器、数据采集模块和第一转换模块，所述数据采集模块连接外部的功放模块，其中：
    所述数据采集模块，配置为对所述功放模块的多个通道的输出信号进行分时采集，并输出多个模拟反馈信号至所述第一转换模块；
    所述第一转换模块，配置为将所述多个模拟反馈信号转换为多个数字反馈信号，并发送给所述校正参数训练器；
    所述校正参数训练器，配置为根据所述多个数字反馈信号和输入的前向信号确定校正参数，并将所述校正参数输出给所述信号失真校正网络模块；以及
    所述信号失真校正网络模块，配置为基于所述校正参数对所述前向信号进行校正后，输出预校正信号。
  2. 根据权利要求1所述的信号失真预校正装置，其中，所述校正参数训练器包括数据线性处理模块和校正参数计算模块，其中：
    所述数据线性处理模块，配置为对所述前向信号和所述多个数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；以及
    所述校正参数计算模块，配置为基于预设信号失真预校正模型、所述线性处理后的前向信号、所述线性处理后的数字反馈信号以及所述预校正信号，构造多个信号矩阵；将所述多个信号矩阵分别使用对应的加权因子进行加权处理，以生成组合矩阵；基于所述组合矩阵获取非线性失真预补偿参数；以及，基于所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定链路失衡校准参数；
    其中，所述多个信号矩阵中的至少一个信号矩阵与所述多个通道中所采集的通道存在对应关系，且所述至少一个信号矩阵对应的加权因子与所述至少一个信号矩阵对应的所述所采集的通道的性能正相关。
  3. 根据权利要求2所述的信号失真预校正装置，其中，所述多个 通道中的第j个通道对应的信号矩阵的加权因子α j为：
    Figure PCTCN2019130264-appb-100001
    Figure PCTCN2019130264-appb-100002
    其中，K为所述多个通道的总通道数，ACPR j是所述第j个通道的邻信道功率比。
  4. 根据权利要求2所述的信号失真预校正装置，其中，所述信号失真校正网络模块包括：第一滤波器组、非线性失真校正模块、链路失衡校正模块和第二滤波器组，其中：
    所述第一滤波器组，配置为对所述前向信号进行速率变换处理，输出变换后的前向信号至所述非线性失真校正模块；
    所述非线性失真校正模块，配置为根据所述校正参数中所述非线性失真预补偿参数对所述变换后的前向信号进行校正生成第一校正信号，并输出所述第一校正信号至所述链路失衡校正模块；
    所述链路失衡校正模块，配置为根据所述校正参数中的所述链路失衡校准参数对所述第一校正信号进行处理，并输出第五校正信号至所述第二滤波器组；以及
    所述第二滤波器组，配置为对所述第五校正信号进行速率变换处理，输出所述预校正信号。
  5. 根据权利要求1所述的信号失真预校正装置，其中，所述校正参数训练器包括数据线性处理模块和校正参数计算模块，其中：
    所述数据线性处理模块，配置为对所述前向信号和所述多个数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；以及
    所述校正参数计算模块，配置为根据所述功放模块的功放模型、所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定失配滤波系数和互耦滤波系数；基于预设信号失真预校正模型、所述失配滤波系数、所述互耦滤波系数、所述线性处理后的前向信号、所述线性处理后的数字反馈信号以及所述预校正信号，构造多个信号矩阵；将所述多个信号矩阵分别使用对应的加权因子进行加权处理，以 生成组合矩阵；基于所述组合矩阵获取非线性失真预补偿参数、失配补偿参数和互耦补偿参数；以及，基于所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定链路失衡校准参数；
    其中，所述多个信号矩阵中的至少一个信号矩阵与所述多个通道中所采集的通道存在对应关系，且所述至少一个信号矩阵对应的加权因子与所述至少一个信号矩阵对应的所述所采集的通道的性能正相关。
  6. 根据权利要求5所述的信号失真预校正装置，其中，所述多个通道中的第j个通道对应的信号矩阵为：
    Figure PCTCN2019130264-appb-100003
    Figure PCTCN2019130264-appb-100004
    其中，
    Figure PCTCN2019130264-appb-100005
    K为所述多个通道的总通道数，x j为所述线性处理后的前向信号，z j为所述预校正信号，y′ j为所述线性处理后的数字反馈信号，h a为所述失配滤波系数，h b为所述互耦滤波系数，L、Q分别为所述预设信号失真预校正模型的记忆深度和非线性阶数；N+1为构造所述多个信号矩阵所用的数据长度。
  7. 根据权利要求5所述的信号失真预校正装置，其中，所述信号失真校正网络模块包括：第一滤波器组、非线性失真校正模块、合并模块、链路失衡校正模块和第二滤波器组；以及，所述信号失真校正网络模块还包括：失配滤波模块和失配误差补偿模块组成的失配校正单元，和/或互耦滤波模块和互耦误差补偿模块组成的互耦校正单元，其中：
    所述第一滤波器组，配置为对所述前向信号进行速率变换处理，输出变换后的前向信号至所述非线性失真校正模块、所述失配滤波模块和所述互耦滤波模块；
    所述非线性失真校正模块，配置为根据所述校正参数中所述非线性失真预补偿参数对所述变换后的前向信号进行校正生成第一校正信号，并输出所述第一校正信号至所述合并模块；
    所述失配滤波模块，配置为根据所述校正参数中的所述失配滤波系数对所述变换后的前向信号进行滤波生成第一中间信号，并输出所述第一中间信号至所述失配误差补偿模块；
    所述失配误差补偿模块，配置为根据所述校正参数中的所述失配补偿参数对所述第一中间信号进行校正得到第二校正信号，并输出所述第二校正信号至所述合并模块；
    所述互耦滤波模块，配置为根据所述校正参数中的所述互耦滤波系数对所述变换后的前向信号进行滤波第二中间信号，并输出所述第二中间信号至所述互耦误差补偿模块；
    所述互耦误差补偿模块，配置为根据所述校正参数中的所述互耦补偿参数对所述第二中间信号进行校正得到第三校正信号，并输出所述第三校正信号至所述合并模块；
    所述合并模块，配置为对其各输入信号进行合并得到第四校正信号，并输出所述第四校正信号至所述链路失衡校正模块；
    所述链路失衡校正模块，配置为根据所述校正参数中的所述链路失衡校准参数对所述第四校正信号进行处理，并输出第五校正信号至所述第二滤波器组；以及
    所述第二滤波器组，配置为对所述第五校正信号进行速率变换处理，输出所述预校正信号。
  8. 根据权利要求1至7任一项所述的信号失真预校正装置，其中，所述数据采集模块包括：信号耦合网络模块和信号取样控制器，所述信号耦合网络模块连接所述功放模块，其中：
    所述信号取样控制器，配置为控制所述信号耦合网络模块，实现对所述多个通道的输出信号的分时采集；以及
    所述信号耦合网络模块，配置为根据所述信号取样控制器的控制，对所述多个通道的输出信号进行分时耦合，输出所述多个模拟反馈信号至所述第一转换模块。
  9. 一种信号失真预校正方法，包括：
    对功放模块的多个通道的输出信号进行分时采集，获得多个模拟反馈信号；
    将所述多个模拟反馈信号转换为多个数字反馈信号；
    根据所述多个数字反馈信号和输入的前向信号确定校正参数；以及
    基于所述校正参数对所述前向信号进行校正得到预校正信号。
  10. 根据权利要求9所述的信号失真预校正方法，其中，根据所述多个数字反馈信号和输入的所述前向信号确定所述校正参数，包括：
    对所述前向信号和所述多个数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；
    基于预设信号失真预校正模型、所述线性处理后的前向信号、所述线性处理后的数字反馈信号以及所述预校正信号，构造多个信号矩阵；以及
    将所述多个信号矩阵分别使用对应的加权因子进行加权处理，以生成组合矩阵，基于所述组合矩阵获取非线性失真预补偿参数，以及基于所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定链路失衡校准参数；
    其中，所述多个信号矩阵中的至少一个信号矩阵与所述多个通道中所采集的通道存在对应关系，且所述至少一个信号矩阵对应的加权因子与所述至少一个信号矩阵对应的所述所采集的通道的性能正相关。
  11. 根据权利要求10所述的信号失真预校正方法，其中，所述多个通道中的第j个通道对应的信号矩阵的加权因子α j为：
    Figure PCTCN2019130264-appb-100006
    Figure PCTCN2019130264-appb-100007
    其中，K为所述多个通道的总通道数，ACPR j是所述第j个通道的邻信道功率比。
  12. 根据权利要求10所述的信号失真预校正方法，其中，基于 所述校正参数对输入的所述前向信号进行校正得到所述预校正信号，包括：
    对所述前向信号进行速率变换处理得到变换后的前向信号；
    根据所述校正参数中所述非线性失真预补偿参数对所述变换后的前向信号进行校正生成第一校正信号；
    根据所述校正参数中的所述链路失衡校准参数对所述第一校正信号进行处理，得到第五校正信号；以及
    对所述第五校正信号进行速率变换处理，得到所述预校正信号，并输出所述预校正信号。
  13. 根据权利要求9所述的信号失真预校正方法，其中，根据所述多个数字反馈信号和输入的所述前向信号确定所述校正参数，包括：
    对所述前向信号和所述多个数字反馈信号进行线性处理，得到线性处理后的前向信号和线性处理后的数字反馈信号；
    根据所述功放模块的功放模型、所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定失配滤波系数和互耦滤波系数；
    基于预设信号失真预校正模型、预设失配滤波系数、预设互耦滤波系数、预设线性处理后的前向信号、预设线性处理后的数字反馈信号以及所述预校正信号，构造多个信号矩阵；以及
    将所述多个信号矩阵分别使用对应的加权因子进行加权处理，以生成组合矩阵，基于所述组合矩阵获取非线性失真预补偿参数、失配补偿参数和互耦补偿参数，以及，基于所述线性处理后的前向信号和所述线性处理后的数字反馈信号确定链路失衡校准参数；
    其中，所述多个信号矩阵中的至少一个信号矩阵与所述多个通道中所采集的通道存在对应关系，且所述至少一个信号矩阵对应的加权因子与所述至少一个信号矩阵对应的所述所采集的通道的性能正相关。
  14. 根据权利要求13所述的信号失真预校正方法，其中，所述多个通道中的第j个通道对应的信号矩阵为：
    Figure PCTCN2019130264-appb-100008
    Figure PCTCN2019130264-appb-100009
    K为所述多个通道的总通道数，x j为所述线性处理后的前向信号，z j为所述预校正信号，y′ j为所述线性处理后的数字反馈信号，h a为所述失配滤波系数，h b为所述互耦滤波系数，L、Q分别为所述预设信号失真预校正模型的记忆深度和非线性阶数；N+1为构造所述多个信号矩阵所用的数据长度。
  15. 根据权利要求13所述的信号失真预校正方法，其中，基于所述校正参数对输入的所述前向信号进行校正得到所述预校正信号包括：
    对所述前向信号进行速率变换处理得到变换后的前向信号；
    根据所述校正参数中的所述非线性失真预补偿参数对所述变换后的前向信号进行校正生成第一校正信号；
    根据所述校正参数中的所述失配滤波系数对所述变换后的前向信号进行滤波生成第一中间信号；
    根据所述校正参数中的所述失配补偿参数对所述第一中间信号进行校正得到第二校正信号；
    根据所述校正参数中的所述互耦滤波系数对所述变换后的前向信号进行滤波生成第二中间信号；
    根据所述校正参数中的所述互耦补偿参数对所述第二中间信号进行校正得到第三校正信号；
    将所述第一校正信号和所述第二校正信号，或者所述第一校正信号和所述第三校正信号，或者所述第一校正信号、所述第二校正信号和所述第三校正信号进行合并得到第四校正信号；
    根据所述校正参数中的所述链路失衡校准参数对所述第四校正信号进行处理生成第五校正信号；以及
    对所述第五校正信号进行速率变换处理得到所述预校正信号，并输出所述预校正信号。
  16. 一种信号失真预校正系统，包括如权利要求1至8任一项所述的信号失真预校正装置，还包括第二转换模块、模拟波束赋形处理器和所述功放模块，其中：
    所述信号失真预校正装置，还配置为输出所述预校正信号至所述第二转换模块；
    所述第二转换模块，配置为将所述预校正信号转换为模拟信号，输出所述模拟信号至所述模拟波束赋形处理器；
    所述模拟波束赋形处理器，配置为对输入的所述模拟信号进行幅度和相位的加权处理，生成加权处理后的模拟信号，并输出至所述功放模块；以及
    所述功放模块，配置为对所述加权处理后的模拟信号进行放大处理后输出。
  17. 一种信号失真预校正复合系统，包括多个如权利要求16所述的信号失真预校正系统，且所述多个信号失真预校正系统复用同一个校正参数训练器，所述校正参数训练器通过至少一个选择开关与所述多个信号失真预校正系统中的相关模块相连。
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