WO2021148061A2 - 一种适用于5g宽带mimo系统的dpd装置及方法 - Google Patents

一种适用于5g宽带mimo系统的dpd装置及方法 Download PDF

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WO2021148061A2
WO2021148061A2 PCT/CN2021/091983 CN2021091983W WO2021148061A2 WO 2021148061 A2 WO2021148061 A2 WO 2021148061A2 CN 2021091983 W CN2021091983 W CN 2021091983W WO 2021148061 A2 WO2021148061 A2 WO 2021148061A2
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signal
feedback
dpd
output
channel
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French (fr)
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WO2021148061A3 (zh
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陈平
王从瑞
彭金民
秦玉峰
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南京濠暻通讯科技有限公司
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Priority to US17/311,360 priority Critical patent/US20230361722A1/en
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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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/24—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • 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
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
    • 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
    • H03F3/213—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only in integrated circuits
    • 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
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B1/0475—Circuits with means for limiting noise, interference or distortion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/451—Indexing scheme relating to amplifiers the amplifier being a radio frequency amplifier
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B2001/0408—Circuits with power amplifiers
    • H04B2001/0425—Circuits with power amplifiers with linearisation using predistortion

Definitions

  • the present invention relates to the field of wireless communication technology, and in particular to a DPD device and method suitable for a 5G broadband MIMO system.
  • the output signal of the RF power amplifier needs to be fed back.
  • the feedback signal is digitally processed and sent to the DPD core algorithm.
  • the DPD model uses the feedback signal and the input signal to iteratively process, extract the predistortion coefficient, correct the predistortion of the input signal, and then Through the non-linear RF power amplifier, the linearized signal output is finally obtained.
  • the distortion of the power amplifier is composed of amplitude-amplitude distortion (AM-AM), amplitude-phase distortion (AM-PM) and distortion caused by the memory effect.
  • AM-AM amplitude-amplitude distortion
  • AM-PM amplitude-phase distortion
  • 5G signals use a larger bandwidth.
  • the wider the system bandwidth the more obvious the memory effect of the RF power amplifier, the more serious the nonlinear effect, and the more complicated the linearization process.
  • new communication systems have increasingly demanding delays, and the DPD model is also required to quickly respond to the distortion caused by the RF power amplifier.
  • the feedback signal loop mainly adopts a separate feedback for each channel and a multi-channel switching feedback method.
  • Each channel of separate feedback requires higher hardware requirements, and each channel of RF amplifier requires a separate channel of feedback loop, down-conversion, analog-to-digital conversion and other resources.
  • the advantage is that it can monitor the transmitted signal in real time and respond in time.
  • the multi-channel switching mode requires polling to feedback each signal. When the number of channels is large, the polling cycle takes a long time and the hardware resources are less occupied, but the response is not timely.
  • the present invention provides a DPD device and method suitable for a 5G broadband MIMO system, which has the advantages of occupying less hardware resources, real-time monitoring of DPD feedback loop signals, and timely response.
  • a DPD device suitable for 5G broadband MIMO system including a data processing module, a digital-to-analog conversion module, a signal output module, a signal feedback module, and an analog-to-digital conversion module,
  • the data processing module iteratively processes the baseband input signal and feedback signal, obtains the predistortion coefficient, performs DPD processing on the baseband signal through the established DPD model, and then connects to the digital-to-analog conversion module;
  • the digital-to-analog conversion module performs digital-to-analog conversion on the predistorted signal processed by the data processing module, performs quadrature IQ modulation after filtering, and connects to the signal output module;
  • the signal output module performs power amplification and filtering processing on the signal input from the digital-to-analog conversion module, and then transmits and outputs it through the antenna;
  • the signal feedback module is to ensure that the feedback signal has at least two feedback paths, the first feedback path is the main feedback loop, and the second feedback path is the auxiliary feedback loop;
  • the main feedback loop uses the switch mode to share feedback for multiple output signals. Only one output signal feedback can be turned on at the same time, which is used for the main adjustment of the DPD coefficient. When the output of all channels is normal, the polling is turned on in time. Update the DPD coefficient of each channel to ensure the best linearity of the output signal of the updated channel;
  • the auxiliary feedback loop provides feedback through air interface coupling or multiple output signal coupling and then combined.
  • the feedback signal contains a combination of multiple output signals, which is used for real-time monitoring of the signal. It is used as a preselector for the output signal distortion channel. When there is a serious distortion signal output, judge the distortion signal output channel, and quickly complete the main adjustment of the DPD coefficient by switching the main feedback loop to the channel with the most severe distortion of the output signal.
  • the auxiliary feedback loop is also used as the auxiliary adjustment of the DPD coefficient to adjust the output signal. When the distortion is small, finely adjust the DPD coefficient;
  • the analog-to-digital conversion module demodulates the feedback signal of the signal feedback module and then performs analog-to-digital conversion, which is connected to the data processing module.
  • the signal feedback module includes multiple coupling units, multiple transmitting antennas, and radio frequency switches.
  • the multiple coupling units receive multiple power signals output by the signal output module, and output multiple transmitted signals and multiple coupled signals;
  • Multiple transmitting antennas are connected to multiple coupling units to receive multiple transmission signals and radiate multiple transmission signals;
  • the main feedback loop receives multiple coupling signals, and outputs a coupling signal through the RF switch, which is demodulated by IQ, low-pass filtering, After ADC conversion, it enters the data processing module;
  • the auxiliary feedback loop consists of a coupled antenna that receives multiple composite transmission signals to form a feedback signal, which enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion.
  • the data processing module includes multiple DPD processing modules, two DPD adaptation modules and a controller.
  • Multiple DPD processing modules process multiple baseband signals to compensate for the introduced nonlinear distortion;
  • two DPD adaptation modules Receive two digital feedback signals of the main feedback loop and the auxiliary feedback loop, adjust the DPD output signal through a plurality of DPD processing modules, the controller receives the digital baseband signal and the digital feedback signal, and controls the radio frequency switch according to the state of the feedback signal.
  • the signal feedback module also includes a plurality of two power dividers, and the plurality of two power dividers receive multiple coupling signals sent by the coupling unit, divide each coupling signal into two, and output two channels and multiple
  • the power division coupling signal multiple power division coupling signals are used as the main feedback loop through the radio frequency switch, and the other multiple power division coupling signals are synthesized by the combiner as the auxiliary feedback loop.
  • the adopted technical solution is: a DPD method suitable for 5G broadband MIMO system, including the following steps:
  • Step S01 According to the auxiliary feedback loop signal, monitor the signal power of each radio frequency channel in real time, and estimate the degree of nonlinear distortion of the radio frequency power amplifier of each radio frequency channel;
  • Step S02 Obtain the most severely distorted radio frequency channel, and switch the main feedback loop to the most severely distorted radio frequency channel;
  • Step S03 Obtain the accurate output power and nonlinear distortion state of the channel through the main feedback loop, obtain the channel coefficients through the improved DPD model, and quickly update the RF channel coefficients to maintain the linear output of the channel RF signal;
  • Step S04 Continue to obtain other RF channels with the most severe nonlinear distortion according to the auxiliary feedback loop signal, and update the channel coefficients.
  • the DPD model is a dynamic deviation dimensionality reduction method, which is expressed as:
  • x(n) and y(n) represent the composite envelope of input and output respectively
  • h p,0 (0,...0) and h p,r (0,...,0,i 1 ,. .., i r ) represents the p-order Volterra kernel
  • P is the non-linear order (odd number)
  • M represents the memory depth.
  • Adopting multi-channel switching and multi-channel signal composite two-channel feedback combination form which not only reduces the shortcomings of multi-channel signal independent feedback occupying more hardware resources, but also improves the problem of slow response to multi-channel signal polling feedback;
  • the present invention has less increase in hardware resources, lower cost, simple method and easy implementation;
  • the present invention improves the reliability of the feedback system due to the dual feedback form
  • the invention When the invention is applied to a beam synthesis system, it can also be used to monitor the output signal phase information of each channel in real time, and monitor the synthesis effect of the beam synthesis signal;
  • the present invention adopts a new DPD model algorithm, which reduces model complexity while maintaining high accuracy, saves hardware logic resources, and accelerates system response speed.
  • Fig. 1 is an overall block diagram of a DPD device suitable for a 5G broadband MIMO system according to the present invention
  • Fig. 2 is a flowchart of the DPD method applicable to the 5G broadband MIMO system of the present invention
  • Figure 3 illustrates a schematic block diagram of the device of the present invention
  • Fig. 4 illustrates the principle block diagram of another device of the present invention.
  • the present invention discloses a DPD device suitable for a 5G broadband MIMO system, which includes a data processing module 1, a digital-to-analog conversion module 2, a signal output module 3, a signal feedback module 4, and an analog-to-digital conversion module 5.
  • the data processing module 1 iteratively processes the baseband input signal and the feedback signal, obtains the predistortion coefficient, performs DPD processing on the baseband signal through the established DPD model, and then connects to the digital-to-analog conversion module 2;
  • the digital-to-analog conversion module 2 performs digital-to-analog conversion on the predistorted signal processed by the data processing module 1, and performs quadrature IQ modulation after filtering, and is connected to the signal output module 3;
  • the signal output module 3 performs power amplification and filtering processing on the signal input by the digital-to-analog conversion module 2, and then transmits and outputs it through the antenna;
  • the signal feedback module 4 is to ensure that the feedback signal has at least two feedback paths, the first feedback path is the main feedback loop, and the second feedback path is the auxiliary feedback loop;
  • the main feedback loop uses the switch mode to share feedback for multiple output signals. Only one output signal feedback can be turned on at the same time, which is used for the main adjustment of the DPD coefficient. When the output of all channels is normal, the polling is turned on in time. Update the DPD coefficient of each channel to ensure the best linearity of the output signal of the updated channel;
  • the auxiliary feedback loop provides feedback through air interface coupling or multiple output signal coupling and then combined.
  • the feedback signal contains a combination of multiple output signals, which is used for real-time monitoring of the signal. It is used as a preselector for the output signal distortion channel. When there is a serious distortion signal output, judge the distortion signal output channel, and quickly complete the main adjustment of the DPD coefficient by switching the main feedback loop to the channel with the most severe distortion of the output signal.
  • the auxiliary feedback loop is also used as the auxiliary adjustment of the DPD coefficient to adjust the output signal. When the distortion is small, finely adjust the DPD coefficient;
  • the analog-to-digital conversion module 5 demodulates the feedback signal of the signal feedback module 4 and then performs analog-to-digital conversion, and is connected to the data processing module 1.
  • a DPD method suitable for 5G broadband MIMO systems includes the following steps:
  • Step S01 According to the auxiliary feedback loop signal, monitor the signal power of each radio frequency channel in real time, and estimate the degree of nonlinear distortion of the radio frequency power amplifier of each radio frequency channel;
  • the auxiliary feedback loop signal contains multiple RF channel feedback signals.
  • the auxiliary feedback loop signal is composed of multiple RF channel feedback signals. Because each RF channel signal contained in the auxiliary feedback loop signal is transmitted with the RF channel The signals have been calibrated.
  • the auxiliary feedback loop signal can be monitored in real time, and the state of each radio frequency channel signal can be decomposed and calculated, and the degree of nonlinear distortion of each channel's radio frequency power amplifier can be estimated through the feedback loop signal state.
  • Step S02 Obtain the most severely distorted radio frequency channel, and switch the main feedback loop to the most severely distorted radio frequency channel;
  • the main feedback loop is a feedback path that contains only one RF channel signal in the feedback loop signal. Since the main feedback loop signal contains only one channel signal, it can more accurately reflect the various states of the RF channel. According to the non-linear distortion degree of each channel RF power amplifier estimated in step S01, sort according to the non-linear distortion degree of each RF channel, obtain the RF channel with the most serious signal non-linear distortion among all the RF channels, and connect the main feedback loop The feedback path is switched to the RF channel with the most severe signal distortion.
  • Step S03 Obtain the accurate output power and nonlinear distortion state of the channel through the main feedback loop, obtain the channel coefficients through the improved DPD model, and quickly update the RF channel coefficients to maintain the linear output of the channel RF signal;
  • the main feedback loop has been connected to the RF channel with the most severe nonlinear distortion, and the precise state of the RF channel signal is obtained through calculation, including the RF output power and the nonlinear distortion state caused by the power amplifier.
  • the dynamic deviation dimensionality reduction method proposes an effective order reduction method, which removes the high-order dynamic memory effect, because in many actual RF power amplifiers, the influence of the nonlinear dynamic memory effect will increase with the increase of the nonlinear order. And weaken.
  • the number of coefficients increases exponentially with the nonlinear order and memory length, while in the reduced-order model, the number of coefficients increases almost linearly with the nonlinear order and memory length. Since the model complexity is significantly reduced after the high-order dynamic memory effect is truncated, the Volterra model can be used to accurately characterize power amplifiers with strong static nonlinearity and long-term linearity and low-order nonlinear memory effects.
  • x(n) and y(n) represent the composite envelope of input and output respectively.
  • h p,0 (0,...0) and h p,r (0,...,0,i 1 ,...,i r ) represent Volterra kernels of order p.
  • P is the non-linear order (odd number)
  • M is the memory depth.
  • the first-order model can be expressed as:
  • x(n) and y(n) represent the baseband complex envelope of the input and output respectively.
  • Step S04 Continue to obtain other RF channels with the most severe nonlinear distortion according to the auxiliary feedback loop signal, and update the channel coefficients.
  • step S03 the coefficient of the radio frequency channel with the most serious nonlinear distortion has been updated, and the indicated radio frequency channel has completed signal linearization output.
  • the auxiliary feedback loop has already acquired the other RF channels with the most severe nonlinear distortion currently referred to, and then the main feedback loop is switched to the RF channel with the most severe nonlinear distortion at present to complete the current RF channel coefficient update. Repeat the above steps to keep the linearized output of all RF channel signals at all times.
  • the data processing module 1 is mainly but not limited to a field programmable logic gate array (FPGA), which is responsible for the joint processing content of the baseband input signal, the output feedback signal, and the signals of each module.
  • the data processing module 1 mainly implements baseband signal preprocessing, DPD model realization, output feedback signal analysis, module control, digital-to-analog conversion control, analog-to-digital conversion control, local oscillator frequency control and signal gain control.
  • the baseband signal preprocessing is to parse out the instructions and data from the input baseband signal. According to different instructions, the baseband input signal data is preprocessed and divided into two channels. One is used to input the DPD model for DPD preprocessing, and the other is used for Do iterative operations with the feedback signal to obtain the coefficients of the RF channel.
  • the implementation of the DPD model is based on the dynamic deviation dimensionality reduction method described in step S03 in the method of the present invention, and the FPGA hardware description language logic algorithm is used to implement the algorithm.
  • Feedback signal analysis means that after the signal is output by the RF power amplifier, it returns to the data processing module through the feedback loop and is digitally quantized. Based on the digital quantized data, the signal information of each channel is calculated, including the signal amplitude and phase information of each RF channel, and the RF channel The degree of nonlinear distortion.
  • Module control refers to the judgment based on the signal state obtained after the above-mentioned feedback signal analysis, and further operations are carried out according to the judgment result. For example, according to the degree of nonlinear distortion of the RF channel, the RF channel with the most severe nonlinear distortion is obtained, and the RF switch of the main feedback loop is controlled to switch to the RF channel.
  • the digital-to-analog conversion control refers to the format conversion, alignment, synchronization and other processing of the digital baseband signal after the DPD model processing is converted into an analog signal.
  • the analog-to-digital conversion control means that when the feedback signal is converted into a digital signal, processing such as synchronization, alignment, and format conversion is performed on it.
  • the local oscillator frequency control is the configuration processing of the local oscillator frequency used for the up-down conversion of the radio frequency.
  • Signal gain control refers to the gain configuration processing of transmitting and receiving channels during communication.
  • the digital-to-analog conversion module 2 converts the predistortion signal processed by the data processing module into an analog signal, and then performs quadrature (IQ) modulation with the local oscillator signal after filtering.
  • IQ quadrature
  • the modulated radio frequency signal is filtered again, and then connected to the signal output Module 3.
  • the signal output module 3 performs power amplification, filtering processing, transmission and reception isolation on the signal input from the digital-to-analog conversion module 2, and then transmits and outputs the signal via an antenna.
  • circulators and radio frequency switching elements can be used for transceiver isolation
  • multiplexers can be used for transceiver isolation.
  • the signal feedback module 4 ensures that the feedback signal has at least two feedback paths, the first feedback path is the main feedback loop, and the second feedback path is the auxiliary feedback loop.
  • the signal output by the RF power amplifier is fed back.
  • the feedback loop is composed of two channels, one of which is for each RF channel to feed back separately, and the feedback signal of each RF channel is switched by the RF switch to demodulation. After the down-conversion, it is filtered and then enters the analog-to-digital converter (ADC). Therefore, the feedback loop has only one signal connected to the ADC at the same time and converted into a digital signal. This feedback signal is called the main feedback loop.
  • the main adjustment of the DPD coefficient when all the channel outputs are normal, the polling is turned on, and the DPD coefficient of each channel is updated in time to ensure the best linearity of the output signal of the channel.
  • the other feedback signal is combined by multiple feedback loops and then fed back. Generally, the number of RF channels in the combined feedback loop does not exceed 8.
  • the multiple RF channels of this feedback loop can be combined in various forms, which can be air interface coupling or multiple After the output signals are coupled, they are combined by a combiner.
  • This feedback loop is called an auxiliary feedback loop, which is used for real-time signal monitoring and serves as a preselector for the output signal distortion channel.
  • the main feedback loop When there is a serious distortion signal output in the channel, it is judged Distorted signal output channel, by switching the main feedback loop to the channel with the most severe output signal distortion, the main adjustment of the DPD coefficient is quickly completed.
  • the auxiliary feedback loop also serves as the auxiliary adjustment of the DPD coefficient. When the output signal distortion is small, the DPD coefficient can be finely adjusted.
  • the analog-to-digital conversion module 5 couples the signal output from the power amplifier, performs (IQ) demodulation of the coupled signal and the local oscillator signal, filters the analog-to-digital conversion into a digital signal, and inputs it to the data processing module.
  • the example shown in Figure 3 includes a data processing module, multiple DACs, multiple up-conversion modulators, a local oscillator source, multiple RF filters, multiple RF power amplifiers, multiple coupling units, multiple transmitters Antenna, a main feedback loop and an auxiliary feedback loop
  • Data processing module containing multiple DPD processing channels, outputting multiple digital baseband signals
  • Multiple DACs connected to multiple DPD processing channels, receive multiple digital baseband signals and convert them into analog baseband signals;
  • Multiple up-conversion modulators connected to multiple DACs, receive multiple analog baseband signals and output modulated radio frequency signals;
  • One local oscillator source connected to multiple up-conversion modulators, and output the local oscillator signal for up-conversion;
  • Multiple RF filters connected to multiple up-conversion modulators, receive multiple RF signals, perform filtering processing, and output filtered RF signals;
  • Multiple RF power amplifiers connected to multiple RF filters, receive filtered RF signals, and amplify the output power signals;
  • Multiple coupling units connected to multiple RF power amplifiers, receive multiple power signals, and output multiple transmission signals and multiple coupling signals;
  • Multiple transmitting antennas connected to multiple coupling units, receiving multiple transmitting signals, and radiating and outputting multiple transmitting signals;
  • a main feedback loop receives multiple coupled signals, outputs a coupled signal through the RF switch, and enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion;
  • An auxiliary feedback loop consists of a coupled antenna that receives multiple composite transmission signals to form a feedback signal, which enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion.
  • Data processing module 1 includes multiple DPD processing modules, two DPD adaptation modules, and a controller. Multiple DPD processing modules process multiple baseband signals to compensate for nonlinear distortion introduced by multiple RF power amplifiers; two DPD adaptation modules Receives two digital feedback signals, the main feedback loop and the auxiliary feedback loop, and adjusts the DPD output signal through multiple DPD processing modules.
  • the controller receives the digital baseband signal and the digital feedback signal, and controls the radio frequency switch according to the state of the feedback signal.
  • the signal feedback module 4 includes multiple coupling units, multiple transmitting antennas and radio frequency switches. Multiple coupling units receive multiple power signals output by the signal output module 3, and output multiple transmission signals and multiple coupling signals; multiple transmission antennas are connected To multiple coupling units, receive multiple transmission signals, and radiate multiple transmission signals; the main feedback loop receives multiple coupling signals, and outputs a coupling signal through the RF switch, and enters the data after IQ demodulation, low-pass filtering, and ADC conversion Processing module; Auxiliary feedback loop, a coupled antenna receives multiple composite transmission signals to form a feedback signal, which enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion.
  • the key to the realization of the example shown in Figure 3 lies in the design of the transmitting antenna and the coupling antenna.
  • the design of the coupling antenna is close to the transmitting antenna of each channel.
  • the coupling coefficient of the transmitting antenna of each channel and the coupling antenna has been calibrated.
  • the amplitude and phase difference between the input signal and the feedback signal of the channel have also been calibrated. Therefore, the status of the radio frequency signal of each channel can be calculated by monitoring the composite feedback signal.
  • the power amplifier of a certain RF channel is working in a non-linear state
  • the feedback loop of the example shown in FIG. 3 is designed in a MIMO system, and it can be used not only for DPD processing, but also for real-time monitoring of the communication quality and channel utilization rate of each transmission channel in the MIMO system.
  • This design can also be used for real-time monitoring of the output signal phase information of each channel in the beam synthesis system, and real-time monitoring of the synthesis effect of the beam synthesis signal.
  • FIG. 4 Another example shown in Figure 4 includes: a data processing module, multiple DACs, multiple up-conversion modulators, a local oscillator source, multiple RF filters, multiple power amplifiers, multiple coupling units, multiple Two power dividers, multiple transmitting antennas, a main feedback loop, and an auxiliary feedback loop.
  • One data processing module, multiple DACs, multiple up-conversion modulators, one local oscillator source, multiple radio frequency filters, multiple power amplifiers, multiple coupling units, and multiple transmitting antennas are the same as those described in FIG. 3.
  • the signal feedback module 4 also includes multiple two power dividers.
  • the multiple two power dividers receive multiple coupling signals sent by the coupling unit, divide each coupled signal into two, and output two multiple power division coupling signals. Multiple power division coupling signals are switched by the radio frequency switch as the main feedback loop, and the other multiple power division coupling signals are synthesized by the combiner as an auxiliary feedback loop.
  • a main feedback loop which receives multiple power division coupling signals, outputs a feedback signal through the RF switch, and enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion;
  • An auxiliary feedback loop receives multiple power division coupling signals from another channel, synthesizes a feedback signal containing multiple power division coupling signals through the combiner, and enters the data processing module after IQ demodulation, low-pass filtering, and ADC conversion.
  • the RF channel signals are independently coupled after being output by the power amplifier.
  • the coupled signals of each RF channel are divided into two paths.
  • One of the coupled signals passes through the RF switch as the main feedback loop, and the other coupled signal passes through
  • the combiner acts as an auxiliary feedback loop after synthesis. Since the path of the feedback signal of each RF channel has been determined, after all RF channels are calibrated, the amplitude and phase difference between the input signal and the feedback signal are also determined, so it can be calculated by monitoring the combined auxiliary feedback signal The status of the RF signal of each channel.
  • the working principle is the same as that shown in Figure 3, which is to adjust the DPD coefficients of multiple RF channels in real time to predistorte the input signals of multiple RF channels, and finally linearize the output of multiple RF channels.

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Abstract

本发明涉及无线通信技术领域，尤其涉及一种适用于5G宽带MIMO系统的DPD装置，包括数据处理模块、数模转换模块、信号输出模块、信号反馈模块和模数转换模块，信号反馈模块是保证DPD反馈信号至少有两个反馈路径，第一个反馈路径为主反馈回路，第二个反馈路径为辅助反馈回路。本发明具有占用硬件资源少，且能够对DPD反馈回路信号进行实时监测，响应及时的优点。

Description

一种适用于5G宽带MIMO系统的DPD装置及方法 技术领域
本发明涉及无线通信技术领域，尤其涉及一种适用于5G宽带MIMO系统的DPD装置及方法。
背景技术
随着无线通信技术发展，对数据传输速率要求不断提高，为了满足在稀缺频谱资源上实现大容量数据传输，现在通信系统都采用高带宽、高阶调制及多输入多输出(MIMO)等技术。这种非恒定包络调制、多载波技术将导致调制信号的高峰均比，加之高宽带应用，对射频功率放大器的线性度提出了更高的要求。为了提高射频功率放大器的效率，降低系统功耗，目前最有效的方式是对数字信号进行预失真(DPD)处理。
采用DPD装置时，需要将射频功率放大器输出信号进行反馈，反馈信号数字化处理后发送给DPD内核算法，DPD模型通过反馈信号和输入信号迭代处理，提取预失真系数，校正输入信号预失真，然后再通过非线性的射频功率放大器，最终得到线性化的信号输出。
功率放大器的失真由幅度-幅度失真(AM-AM)、幅度-相位失真(AM-PM)以及由记忆效应引起的失真。目前5G信号都采用较大带宽，系统带宽越宽，射频功率放大器记忆效应越明显，非线性影响越严重，其线性化处理越复杂。此外新的通信系统对延时要求越来越高，也要求DPD模型能够快速响应射频功率放大器引起的失真。
目前针对多通道MIMO系统或多频段系统的DPD装置，反馈信号回路主要采用每路单独反馈和多路切换反馈方式。每路单独反馈对硬件要求 较高，需要每路射频放大器单独一路反馈回路、下变频、模数转换等资源，优点是能够对发射信号进行实时监测，及时响应。多路切换方式则需要轮询方式对每路信号进行反馈，当通道数较多时轮询一个周期时间较长，硬件资源占用少，但响应不及时。
发明内容
本发明提供了一种适用于5G宽带MIMO系统的DPD装置及方法，具有占用硬件资源少，且能够对DPD反馈回路信号进行实时监测，响应及时的优点。
为了实现本发明的目的，所采用的技术方案是：一种适用于5G宽带MIMO系统的DPD装置，包括数据处理模块、数模转换模块、信号输出模块、信号反馈模块和模数转换模块，
数据处理模块将基带输入信号和反馈信号进行迭代处理，获取预失真系数，通过建立的DPD模型对基带信号进行DPD处理，然后连接至数模转换模块；
数模转换模块将数据处理模块处理后的预失真信号进行数模转换，滤波后进行正交IQ调制，连接至信号输出模块；
信号输出模块将数模转换模块输入的信号进行功率放大、滤波处理，然后经天线发射输出；
信号反馈模块是保证反馈信号至少有两个反馈路径，第一个反馈路径为主反馈回路，第二个反馈路径为辅助反馈回路；
主反馈回路通过开关切换方式为多路输出信号共用反馈，同一时间只能接通其中一路输出信号反馈，用于DPD系数的主调节，在所有通道输出都正常时，进行轮询接通，及时更新各通道DPD系数，保证更新通道 输出信号线性度最佳；
辅助反馈回路通过空口耦合或多路输出信号耦合后再合路的方式进行反馈，反馈信号中含有多路输出信号组合，用于信号的实时监测，作为输出信号失真通道的预选器，当通道中有较严重的失真信号输出时，判断失真信号输出通道，通过将主反馈回路切换至输出信号失真最严重通道，快速完成DPD系数主调节，辅助反馈回路还作为DPD系数的辅助调节，对输出信号失真较小时，细微调节DPD系数；
模数转换模块将信号反馈模块的反馈信号解调后再进行模数转换，连接至数据处理模块。
作为本发明的优化方案，信号反馈模块包括多个耦合单元、多个发射天线和射频开关，多个耦合单元接收信号输出模块输出的多个功率信号，输出多个发射信号和多个耦合信号；多个发射天线连接至多个耦合单元，接收多个发射信号，辐射输出多个发射信号；主反馈回路接收多个耦合信号，通过射频开关切换输出一个耦合信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块；辅助反馈回路，由一个耦合天线，接收复合的多个发射信号，形成一路反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块。
作为本发明的优化方案，数据处理模块包括多个DPD处理模块、两个DPD适应模块和一个控制器，多个DPD处理模块处理多个基带信号，补偿引入的非线性失真；两个DPD适应模块接收主反馈回路和辅助反馈回路两路数字反馈信号，通过多个DPD处理模块调整DPD输出信号，所述控制器接收数字基带信号和数字反馈信号，并根据反馈信号状态，控制射频开关。
作为本发明的优化方案，信号反馈模块还包括多个二功分器，多个二功分器接收耦合单元发送的多个耦合信号，把每个耦合信号一分为二，输出两路多个功分耦合信号，一路多个功分耦合信号通过射频开关切换作为主反馈回路，另一路多个功分耦合信号经过合路器合成后作为辅助反馈回路。
为了实现本发明的目的，所采用的技术方案是：一种适用于5G宽带MIMO系统的DPD方法，包括如下步骤：
步骤S01：根据辅助反馈回路信号，实时监测各射频通道信号功率，并估算各射频通道射频功率放大器的非线性失真程度；
步骤S02：获取非线性失真最严重的射频通道，并将主反馈回路切换至最严重失真射频通道；
步骤S03：通过主反馈回路获取该通道精确输出功率及非线性失真状态，通过改进发明的DPD模型获取通道系数，并快速更新该射频通道系数，保持该通道射频信号的线性输出；
步骤S04：根据辅助反馈回路信号继续获取其它非线性失真最严重的射频通道，并更新通道系数。
作为本发明的优化方案，DPD模型为动态偏差降维法，表示为：
Figure PCTCN2021091983-appb-000001
其中x(n)和y(n)分别代表输入和输出的复合包络，h p,0(0,...0)和h p,r(0,...,0,i 1,...,i r)表示p阶Volterra内核，P为非线性阶数(奇数)，M代表记忆 深度。
本发明具有积极的效果：
1)采用多路切换及多路信号复合两路反馈组合形式，既降低了多路信号单独反馈占用硬件资源多的缺点，又改进了多路信号轮询反馈响应慢的问题；
2)本发明相对传统多通道系统，硬件资源增加较少，成本较低，方法简单，实现容易；
3)本发明由于采用双重反馈形式，提高了反馈系统的可靠性；
4)该发明应用于宽带的多通道MIMO系统时，实时监测MIMO系统中各发射通道的通信质量及通道使用率；
5)该发明应用于波束合成系统时中，也可用于实时监测各通道输出信号相位信息，对波束合成信号的合成效果进行监测；
6)本发明采用新DPD模型算法，保持较高准确度的同时降低了模型复杂度，节省硬件逻辑资源，加快了系统响应速度。
附图说明
下面结合附图和具体实施方式对本发明作进一步详细的说明。
图1是本发明适用于5G宽带MIMO系统的DPD装置的整体框图；
图2是本发明适用于5G宽带MIMO系统的DPD方法的流程图；
图3示例了一种本发明装置的原理框图；
图4示例了另一种本发明装置的原理框图。
其中：1、数据处理模块，2、数模转换模块，3、信号输出模块，4、信号反馈模块，5、模数转换模块。
具体实施方式
如图1所示，本发明公开了一种适用于5G宽带MIMO系统的DPD装置，包括数据处理模块1、数模转换模块2、信号输出模块3、信号反馈模块4和模数转换模块5，
数据处理模块1将基带输入信号和反馈信号进行迭代处理，获取预失真系数，通过建立的DPD模型对基带信号进行DPD处理，然后连接至数模转换模块2；
数模转换模块2将数据处理模块1处理后的预失真信号进行数模转换，滤波后进行正交IQ调制，连接至信号输出模块3；
信号输出模块3将数模转换模块2输入的信号进行功率放大、滤波处理，然后经天线发射输出；
信号反馈模块4是保证反馈信号至少有两个反馈路径，第一个反馈路径为主反馈回路，第二个反馈路径为辅助反馈回路；
主反馈回路通过开关切换方式为多路输出信号共用反馈，同一时间只能接通其中一路输出信号反馈，用于DPD系数的主调节，在所有通道输出都正常时，进行轮询接通，及时更新各通道DPD系数，保证更新通道输出信号线性度最佳；
辅助反馈回路通过空口耦合或多路输出信号耦合后再合路的方式进行反馈，反馈信号中含有多路输出信号组合，用于信号的实时监测，作为输出信号失真通道的预选器，当通道中有较严重的失真信号输出时，判断失真信号输出通道，通过将主反馈回路切换至输出信号失真最严重通道，快速完成DPD系数主调节，辅助反馈回路还作为DPD系数的辅助调节，对输出信号失真较小时，细微调节DPD系数；
模数转换模块5将信号反馈模块4的反馈信号解调后再进行模数转换，连接至数据处理模块1。
如图2所示，一种适用于5G宽带MIMO系统的DPD方法，包括如下步骤：
步骤S01：根据辅助反馈回路信号，实时监测各射频通道信号功率，并估算各射频通道射频功率放大器的非线性失真程度；
辅助反馈回路信号中包含有多个射频通道的反馈信号，该辅助反馈回路信号由多个射频通道反馈信号组合而成，由于该辅助反馈回路信号中包含的每个射频通道信号与该射频通道发送信号之间已经过校准，可以通过实时监测该辅助反馈回路信号，分解计算得到各个射频通道信号的状态，并且可以通过该反馈回路信号状态估算各通道射频功率放大器的非线性失真程度。
步骤S02：获取非线性失真最严重的射频通道，并将主反馈回路切换至最严重失真射频通道；
主反馈回路是反馈回路信号中只含有一个射频通道信号的反馈路径，由于主反馈回路信号只含有一个通道信号，因此可以更加准确的反应射频通道的各种状态。根据步骤S01估算得到的各通道射频功率放大器的非线性失真程度，按照各个射频通道的非线性失真程度进行排序，获取得到所有射频通道中信号非线性失真最严重的射频通道，并将主反馈回路的反馈路径切换至信号失真最严重的射频通道。
步骤S03：通过主反馈回路获取该通道精确输出功率及非线性失真状态，通过改进发明的DPD模型获取通道系数，并快速更新该射频通道系数，保持该通道射频信号的线性输出；
主反馈回路已连接至非线性失真最严重的射频通道，通过计算获取该射频通道信号的精确状态，包括射频输出功率及功率放大器导致的非线性失真状态。通过动态偏差降维法获取该射频通道的DPD模型系数，可以快速完成射频通道DPD模型系数的更新，保持射频通道的线性输出状态。
动态偏差降维法提出了一种有效的降阶方法，该方法去掉了高阶动态记忆效应，因为在许多实际射频功率放大器中，非线性动态记忆效应的影响会随着非线性阶数的增加而减弱。与经典的Volterra模型不同的是，系数的数量随非线性阶数和记忆长度呈指数增长，而在降阶模型中，系数的数量几乎随非线性阶数和记忆长度呈线性增长。由于经过高阶动态记忆效应截断后，模型复杂度显著降低，该Volterra模型可用于准确表征具有静态强非线性和长期线性和低阶非线性记忆效应的功率放大器。通过对Volterra系数的重新分组，使不同的动态阶数可以被控制和分离，同时又保持了模型提取过程的简单性。该方法可以显着降低经典Volterra模型的复杂度，同时不造成模型保真度的损失，静态非线性和不同阶数的动态效应都可以被识别。动态偏差降维法可表示为：
Figure PCTCN2021091983-appb-000002
其中x(n)和y(n)分别代表输入和输出的复合包络。h p,0(0,...0)和h p,r(0,...,0,i 1,...,i r)表示p阶Volterra内核。P为非线性阶数(奇数),M代表记忆深度。
由于许多射频功率放大器具有动态效应随着非线性阶数的增加而衰减的特性，因此可以通过消除高阶动态效应来显着降低模型复杂度，即将 r的值保持在较小范围内(r＝1；2)。
如果动态r等于1，则一阶模型可以表示为：
Figure PCTCN2021091983-appb-000003
Figure PCTCN2021091983-appb-000004
为了在复杂基带中精确建模功率放大器，公式中的模型需要转换为低通等效格式：
Figure PCTCN2021091983-appb-000005
其中x(n)和y(n)分别表示输入和输出的基带复包络。
步骤S04：根据辅助反馈回路信号继续获取其它非线性失真最严重的射频通道，并更新通道系数。
步骤S03中非线性失真最严重的射频通道系数已更新完成，所指射频通道已完成信号线性化输出。同时辅助反馈回路也已获取当前所指的其他非线性失真最严重的射频通道，之后再将主反馈回路切换至当前非线性失真最严重的射频通道，完成当前射频通道系数更新。重复以上各步骤，时刻保持所有射频通道信号的线性化输出。
其中，数据处理模块1主要但不限于现场可编程逻辑门阵列(FPGA)，其负责基带输入信号、输出反馈信号及各模块的信号的联合处理内容。该数据处理模块1主要实现基带信号预处理、DPD模型实现、输出反馈信号分析、模块控制、数模转换控制、模数转换控制、本振频率控制及信号增益控制。
基带信号预处理是从输入的基带信号中解析出指令及数据，根据不同的指令将基带输入信号数据进行预处理后分两路，一路用于输入DPD模型，做DPD预处理，另一路用于和反馈信号做迭代运算获取射频通道的系数。
DPD模型实现是根据本发明方法中步骤S03所述动态偏差降维法，采用FPGA硬件描述语言逻辑算法实现该算法。
反馈信号分析是指信号经过射频功率放大器输出后，通过反馈回路返回数据处理模块并进行数字量化后，根据该数字量化数据计算各通道信号信息，包括各射频通道信号幅度及相位信息，以及射频通道的非线性失真程度。
模块控制是指根据上述反馈信号分析后得到的信号状态进行判断，根据判断结果进行进一步操作。如根据射频通道非线性失真程度，获取非线性失真最严重的射频通道，控制主反馈回路射频开关切换至该射频通道。
数模转换控制是指经过DPD模型处理后的数字基带信号转换为模拟信号时，对其进行格式转换、对齐、同步等处理。
模数转换控制是指反馈信号转换为数字信号时，对其进行同步、对齐、格式转换等处理。
本振频率控制是对射频上下变频所使用的本振频率进行的配置处理。
信号增益控制是指在通信时发射和接收通道的增益配置处理。
数模转换模块2将数据处理模块处理后的预失真信号进行转换为模拟信号，滤波后再与本振信号进行正交(IQ)调制，调制后的射频信号再进行滤波，然后连接至信号输出模块3。
信号输出模块3将数模转换模块2输入的信号进行功率放大、滤波处 理、收发隔离，然后经天线发射输出。对于TDD系统，收发隔离可采用环形器及射频开关元件，对于FDD系统，收发隔离可采用多工器。
信号反馈模块4是保证反馈信号至少有两个反馈路径，第一个反馈路径为主反馈回路，第二个反馈路径为辅助反馈回路。在本实施例中，将射频功率放大器输出后的信号进行反馈，反馈回路由两路组成，其中一路为每个射频通道单独反馈，各射频通道的反馈信号再通过射频开关进行切换后至解调器，下变频后进行滤波，滤波后进入模数转换器(ADC)，因此该反馈回路同一时刻只有一路信号接入ADC，转换为数字信号，该路反馈信号称为主反馈回路，其用于DPD系数的主调节，在所有通道输出都正常时，进行轮询接通，及时更新各通道DPD系数，保证更通道输出信号线性度最佳。另一路反馈信号则由多个反馈回路组合后再进行反馈，一般组合反馈回路中射频通道数量不超过8路，该反馈回路的多个射频通道组合方式有多种形式，可以是空口耦合或多路输出信号耦合后通过合路器进行组合，该反馈回路称为辅助反馈回路，用于信号的实时监测，作为输出信号失真通道的预选器，当通道中有较严重的失真信号输出时，判断失真信号输出通道，通过将主反馈回路切换至输出信号失真最严重通道，快速完成DPD系数主调节，辅助反馈回路还作为DPD系数的辅助调节，对输出信号失真较小时，可以细微调节DPD系数。
模数转换模块5将功率放大器输出后的信号进行耦合，耦合后的信号与本振信号进行(IQ)解调、滤波后模数转换为数字信号，输入至数据处理模块。
如图3所示实例，包括一个数据处理模块、多个DAC、多个上变频模调制器、一个本振源、多个射频滤波器、多个射频功率放大器、多个耦合 单元、多个发射天线、一个主反馈回路和一个辅助反馈回路
数据处理模块，含有多个DPD处理通道，输出多路数字基带信号；
多个DAC，连接至多个DPD处理通道，接收多个数字基带信号并转换为模拟基带信号；
多个上变频调制器，连接至多个DAC，接收多个模拟基带信号并输出调制的射频信号；
一个本振源，连接至多个上变频调制器，输出上变频用本振信号；
多个射频滤波器，接至多个上变频调制器，接收多个射频信号，进行滤波处理，输出滤波后射频信号；
多个射频功率放大器，连接至多个射频滤波器，接收滤波后的射频信号，放大输出功率信号；
多个耦合单元，连接至多个射频功率放大器，接收多个功率信号，输出多个发射信号和多个耦合信号；
多个发射天线，连接至多个耦合单元，接收多个发射信号，辐射输出多个发射信号；
一个主反馈回路，接收多个耦合信号，通过射频开关切换输出一个耦合信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块；
一个辅助反馈回路，由一个耦合天线，接收复合的多个发射信号，形成一路反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块。
数据处理模块1包括多个DPD处理模块、两个DPD适应模块和一个控制器，多个DPD处理模块处理多个基带信号，补偿由多个射频功率放大器引入的非线性失真；两个DPD适应模块接收主反馈回路和辅助反馈 回路两路数字反馈信号，通过多个DPD处理模块调整DPD输出信号，控制器接收数字基带信号和数字反馈信号，并根据反馈信号状态，控制射频开关。
信号反馈模块4包括多个耦合单元、多个发射天线和射频开关，多个耦合单元接收信号输出模块3输出的多个功率信号，输出多个发射信号和多个耦合信号；多个发射天线连接至多个耦合单元，接收多个发射信号，辐射输出多个发射信号；主反馈回路接收多个耦合信号，通过射频开关切换输出一个耦合信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块；辅助反馈回路，由一个耦合天线，接收复合的多个发射信号，形成一路反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块。
图3所述实例的实现关键在于发射天线与耦合天线的设计，耦合天线设计与各通道发射天线距离都较近，每个通道发射天线与该耦合天线的耦合系数都已经校准过，每个发射通道的输入信号与反馈信号之间的幅度及相位差也都已经校准，因此可以通过监测该复合后的反馈信号，计算得到各通道射频信号的状态。当监测到各通道射频功率放大器均工作在线性状态时，调整各通道DPD系数，对输入信号不进行预失真，当监测到某个射频通道功率放大器工作在非线性状态时，调整该射频通道DPD系数，对该通道输入信号进行预失真，最终使该通道输出线性化。
图3所述实例所述反馈回路设计在MIMO系统中，不仅可以用于DPD处理，还可以用于实时监测MIMO系统中各发射通道的通信质量及通道使用率。该设计在波束合成系统中，也可用于实时监测各通道输出信号相位信息，对波束合成信号的合成效果进行实时监测。
如图4所示的另一个实例，包括：一个数据处理模块、多个DAC、多个上变频模调制器、一个本振源、多个射频滤波、多个功率放大器、多个耦合单元、多个二功分器、多个发射天线、一个主反馈回路、一个辅助反馈回路。其中一个数据处理模块、多个DAC、多个上变频模调制器、一个本振源、多个射频滤波、多个功率放大器、多个耦合单元、多个发射天线与图3所述相同。
信号反馈模块4还包括多个二功分器，多个二功分器接收耦合单元发送的多个耦合信号，把每个耦合信号一分为二，输出两路多个功分耦合信号，一路多个功分耦合信号通过射频开关切换作为主反馈回路，另一路多个功分耦合信号经过合路器合成后作为辅助反馈回路。
一个主反馈回路，接收一路多个功分耦合信号，通过射频开关切换输出一个反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块；
一个辅助反馈回路，接收另一路多个功分耦合信号，通过合路器合成为一个包含多个功分耦合信号的反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块。
图4所述实例中各射频通道信号经功率放大器输出后进行单独耦合，每个射频通道耦合后的信号再分为两路，其中一路耦合信号经过射频开关作为主反馈回路，另一路耦合信号经过合路器合成后作为辅助反馈回路。由于每个射频通道的反馈信号的路径都已确定，所有射频通道经过校准之后，输入信号与反馈信号之间的幅度及相位差也都确定，因此可以通过监测组合后的辅助反馈信号，计算得到各通道射频信号的状态。工作原理与图3所示相同，都是通过实时调整多个射频通道DPD系数，对多个射频 通道输入信号进行预失真，最终使多个射频通道输出线性化。
以上所述的具体实施例，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施例而已，并不用于限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (6)

  1. 一种适用于5G宽带MIMO系统的DPD装置，其特征在于：包括数据处理模块(1)、数模转换模块(2)、信号输出模块(3)、信号反馈模块(4)和模数转换模块(5)，
    所述数据处理模块(1)将基带输入信号和反馈信号进行迭代处理，获取预失真系数，通过建立的DPD模型对基带信号进行DPD处理，然后连接至数模转换模块(2)；
    所述数模转换模块(2)将数据处理模块(1)处理后的预失真信号进行数模转换，滤波后进行正交IQ调制，连接至信号输出模块(3)；
    所述信号输出模块(3)将数模转换模块(2)输入的信号进行功率放大、滤波处理，然后经天线发射输出；
    所述信号反馈模块(4)是保证反馈信号至少有两个反馈路径，第一个反馈路径为主反馈回路，第二个反馈路径为辅助反馈回路；
    所述主反馈回路通过开关切换方式为多路输出信号共用反馈，同一时间只能接通其中一路输出信号反馈，用于DPD系数的主调节，在所有通道输出都正常时，进行轮询接通，及时更新各通道DPD系数，保证更新通道输出信号线性度最佳；
    所述辅助反馈回路通过空口耦合或多路输出信号耦合后再合路的方式进行反馈，反馈信号中含有多路输出信号组合，用于信号的实时监测，作为输出信号失真通道的预选器，当通道中有较严重的失真信号输出时，判断失真信号输出通道，通过将主反馈回路切换至输出信号失真最严重通道，快速完成DPD系数主调节，辅助反馈回路还作为DPD系数的辅助调节，对输出信号失真较小时，细微调节DPD系数；
    所述模数转换模块(5)将信号反馈模块(4)的反馈信号解调后再进 行模数转换，连接至数据处理模块(1)。
  2. 根据权利要求1所述的一种适用于5G宽带MIMO系统的DPD装置，其特征在于：所述的信号反馈模块(4)包括多个耦合单元、多个发射天线和射频开关，多个耦合单元接收信号输出模块(3)输出的多个功率信号，输出多个发射信号和多个耦合信号；多个发射天线连接至多个耦合单元，接收多个发射信号，辐射输出多个发射信号；主反馈回路接收多个耦合信号，通过射频开关切换输出一个耦合信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块；辅助反馈回路，由一个耦合天线，接收复合的多个发射信号，形成一路反馈信号，经过IQ解调制、低通滤波、ADC转换后进入数据处理模块。
  3. 根据权利要求2所述的一种适用于5G宽带MIMO系统的DPD装置，其特征在于：所述数据处理模块包括多个DPD处理模块、两个DPD适应模块和一个控制器，多个DPD处理模块处理多个基带信号，补偿引入的非线性失真；两个DPD适应模块接收主反馈回路和辅助反馈回路两路数字反馈信号，通过多个DPD处理模块调整DPD输出信号，所述控制器接收数字基带信号和数字反馈信号，并根据反馈信号状态，控制射频开关。
  4. 根据权利要求3所述的一种适用于5G宽带MIMO系统的DPD装置，其特征在于：所述信号反馈模块(4)还包括多个二功分器，所述的多个二功分器接收耦合单元发送的多个耦合信号，把每个耦合信号一分为二，输出两路多个功分耦合信号，一路多个功分耦合信号通过射频开关切换作为主反馈回路，另一路多个功分耦合信号经过合路器合成后作为辅助反馈回路。
  5. 一种适用于5G宽带MIMO系统的DPD方法，其特征在于：包括如下步骤：
    步骤S01：根据辅助反馈回路信号，实时监测各射频通道信号功率，并估算各射频通道射频功率放大器的非线性失真程度；
    步骤S02：获取非线性失真最严重的射频通道，并将主反馈回路切换至最严重失真射频通道；
    步骤S03：通过主反馈回路获取该通道精确输出功率及非线性失真状态，通过改进发明的DPD模型获取通道系数，并快速更新该射频通道系数，保持该通道射频信号的线性输出；
    步骤S04：根据辅助反馈回路信号继续获取其它非线性失真最严重的射频通道，并更新通道系数。
  6. 根据权利要求5所述的一种适用于5G宽带MIMO系统的DPD方法，其特征在于：所述DPD模型为动态偏差降维法，表示为：
    Figure PCTCN2021091983-appb-100001
    其中x(n)和y(n)分别代表输入和输出的复合包络，h p,0(0,…0)和h p,r(0,…,0,i 1,…,i r)表示p阶Volterra内核，P为非线性阶数，P为奇数，M代表记忆深度。
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