Method, model and communication system for compensating for nonlinear signal distortion

Abstract

The disclosed signal nonlinear distortion compensation method, model, and communication system relate to the wireless communication technology field. In this disclosure, a preset nonlinear compensation fusion model is used to perform DPD processing, CFR processing, and error compensation processing on an initial OFDM signal to obtain a nonlinear distortion-compensated initial OFDM signal. In this nonlinear compensation fusion model, the BL-DPD module, BL-CFR module, and error compensation module are arranged in parallel, avoiding the technical drawbacks of the prior art, where the DPD module is applied after the CFR module, which increases the requirements for the ADC / DAC sampling rate and the requirements for hardware and algorithm convergence speed, thereby increasing the difficulty and cost of system implementation. This not only reduces the requirements for the ADC / DAC sampling rate, but also improves the DPD compensation ability for power amplifier nonlinearities, thereby improving the communication and sensing performance of the OFDM system.

Description

[Technical Field]

[0001] The present disclosure relates to the field of wireless communication technology, and more particularly to a method, model and communication system for compensating for nonlinear distortion of a signal. [Background technology]

[0002] Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier modulation technique that divides a carrier into multiple mutually orthogonal subcarriers to solve frequency selective fading and narrowband interference.

[0003] Therefore, signals modulated using OFDM technology, i.e., OFDM signals, usually have characteristics such as a non-stationary envelope, a wide (frequency) bandwidth, and a high Peak-to-Average Power Ratio (PAPR), etc. However, when an OFDM signal passes through a power amplifier (PA), nonlinear distortion inevitably occurs.

[0004] Initially, to ensure good linearity of the signal output from the power amplifier, simple power back-off methods were usually used, but this method reduced the efficiency of the power amplifier and wasted resources.To improve the efficiency of the power amplifier, the power amplifier was usually operated near its saturation point, which caused severe in-band distortion, increased the bit error rate of the communication system, and also caused out-of-band spectrum spreading and adjacent channel interference.

[0005] In light of this, conventional techniques for reducing the effects of nonlinear distortion in power amplifiers typically utilize crest factor reduction (CFR) and digital predistortion (DPD). CFR reduces the PAPR of a signal by lowering its peak power. This reduction in PAPR reduces the power amplifier's backoff value relative to the output peak power at the average power operating point, thereby improving the power amplifier's efficiency. DPD is an effective method for compensating for the nonlinear and memory effects of power amplifiers in high-efficiency regions. Therefore, combining CFR and DPD simultaneously meets the application needs of improving power amplifier efficiency and linearity.

[0006] Therefore, in the related art, a CFR module and a DPD module can usually be cascaded to achieve improved power amplifier efficiency and linearity. Furthermore, in the technical solution combining the traditional CFR technology and DPD technology, the DPD module is usually applied after the CFR module.

[0007] However, when the CFR module and DPD module are cascaded, the DPD module is applied after the CFR module. This means that the signal that has been peak-clipped and has reduced PAPR through the CFR module experiences a re-increase in PARA after passing through the DPD module. Furthermore, due to the nonlinearity of the power amplifier, spectral spreading occurs in the output signal. This places higher demands on the sampling rate of the analog-to-digital converter (ADC) / digital-to-analog converter (DAC) in the OFDM system, as well as higher demands on the hardware and algorithm convergence speed, increasing the difficulty and cost of implementing the system.

[0008] Therefore, how to reduce the requirements for the sampling rate of the ADC / DAC and improve the DPD compensation ability for the power amplifier nonlinearity are currently technical challenges that need to be solved. Summary of the Invention

[0009] The embodiments of the present disclosure provide a signal nonlinear distortion compensation method, model, and communication system to further improve the communication and sensing capabilities of OFDM systems by reducing the requirements for the sampling rate of ADC / DAC and improving the DPD compensation ability for power amplifier nonlinearity.

[0010] In a first aspect, an embodiment of the present disclosure provides a method for nonlinear distortion compensation of a signal, the method comprising: inputting an initial orthogonal frequency division multiplexing OFDM signal into a preset nonlinear compensation fusion model, the nonlinear compensation fusion model comprising a frequency band limited digital predistortion (BL-DPD) module, a frequency band limited crest factor reduction (BL-CFR) module, and an error compensation module, the error compensation module performing error compensation on the OFDM signal output from the BL-DPD module and the BL-CFR module; For the initial OFDM signal, respectively obtain a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module; and obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0011] In one preferred embodiment, the basis functions used by each of the BL-DPD and BL-CFR modules are the same.

[0012] In one preferred embodiment, for an initial OFDM signal, respectively obtaining a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module includes: and modulating the initial OFDM signal based on the model parameter sets converged in the offline modes of the BL-DPD module, the BL-CFR module, and the error compensation module, to obtain a first OFDM signal, a second OFDM signal, and a third OFDM signal, respectively.

[0013] In one preferred embodiment, the model parameter set is: A combination of parameters consisting of the kernel coefficients, nonlinearity order, memory depth, and order of the low-order low-pass filter (LPF) of the BL-DPD module; A combination of parameters consisting of the kernel coefficients, nonlinearity order, memory depth and order of the low-order LPF of the BL-CFR module; A combination of parameters consisting of kernel coefficients, nonlinearity order, and memory depth of the error compensation module; Contains one of the following:

[0014] In one preferred embodiment, when the parameter combination of the model parameter set consists of the kernel coefficient of the BL-DPD module, the nonlinear order, the memory depth, and the order of the low-order LPF, the model parameter set can be expressed as follows: inputting a sample OFDM signal in offline mode into a BL-DPD module to obtain a sample OFDM signal after DPD processing; Obtaining an inverse DPD sample OFDM signal based on the DPD sample OFDM signal and a conjugate parameter set corresponding to the initial parameter set of the BL-DPD module; Obtaining a target DPD error signal based on the sampled OFDM signal in an offline mode and the sampled OFDM signal after inverse DPD processing; performing iterative modifications to the initial parameter set based on the target DPD error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target DPD error signal is less than the set DPD error signal threshold; The initial parameter set after iterative modification is taken as the model parameter set of the BL-DPD module.

[0015] In one preferred embodiment, obtaining the inverse DPD processed sample OFDM signal based on the DPD processed sample OFDM signal and a conjugate parameter set corresponding to the initial parameter set of the BL-DPD module comprises: performing digital-to-analog conversion, up-converting, and power amplification on the sample OFDM signal after the DPD processing, to obtain a sample OFDM signal after power amplification; performing power attenuation, down-conversion and analog-to-digital conversion processing on the power-amplified sample OFDM signal in order to obtain an analog-to-digital converted sample OFDM signal; and obtaining a sampled OFDM signal after inverse DPD processing based on the sampled OFDM signal after analog-to-digital conversion and a conjugate parameter set corresponding to the initial parameter set.

[0016] In one preferred embodiment, performing iterative modifications to the initial parameter set based on the target DPD error signal and a preset low noise variable step size least mean square algorithm includes: Each time you modify the initial parameter set, Obtaining sample OFDM signals corresponding to each of a plurality of historical time points adjacent to the current sample OFDM signal in an offline mode; obtaining an average value of the DPD error signals at a current time of the sampled OFDM signals in an offline mode based on historical DPD error signals corresponding to each of the plurality of sampled OFDM signals; obtaining a first target step size factor based on an average value of the DPD error signal, a step size factor at a time in history immediately preceding the current time, a target DPD error signal at the current time, and a historical DPD error signal at the time in history immediately preceding the current time; The method includes modifying the initial parameter set at the current time based on the first target step size factor, a conjugate DPD error signal corresponding to the target DPD error signal at the current time, and the sampled OFDM signal after analog-to-digital conversion to obtain a modified initial parameter set; and executing the modified initial parameter set.

[0017] In one preferred embodiment, before making iterative modifications to the initial parameter set based on the target DPD error signal and a preset low noise variable step size least mean square algorithm: If the absolute value of the target DPD error signal is equal to or greater than the DPD error signal threshold, the initial parameter set is used as the model parameter set of the BL-DPD module.

[0018] In one preferred embodiment, when the parameter combination of the model parameter set consists of the kernel coefficient of the BL-CFR module, the nonlinear order, the memory depth and the order of the low-order LPF, the model parameter set is: inputting a sample OFDM signal in offline mode into a BL-DPD module and a preset CFR module in sequence to obtain a sample OFDM signal after DPD-CFR processing; Obtaining a sample OFDM signal after CFR processing based on the sample OFDM signal in an offline mode and a conjugate parameter set corresponding to the initial parameter set of the BL-CFR module; obtaining a target CFR error signal based on the sample OFDM signal after DPD-CFR processing and the sample OFDM signal after CFR processing; performing iterative modifications to the initial parameter set based on the target CFR error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target CFR error signal is less than the set CFR error signal threshold; The initial parameter set after iterative modification is taken as the model parameter set of the BL-CFR module.

[0019] In one preferred embodiment, before making iterative modifications to the initial parameter set based on the target CFR error signal and a preset low noise variable step size least mean squares algorithm: If the absolute value of the target CFR error signal is equal to or greater than the threshold value of the CFR error signal, the initial parameter set is used as the model parameter set of the BL-CFR module.

[0020] In one preferred embodiment, when the parameter combination of the model parameter set consists of the kernel coefficients, the nonlinearity order and the memory depth of the error compensation module, the model parameter set is The sample OFDM signal in offline mode is input to the nonlinear compensation fusion model and the preset high-order LPF, respectively, to obtain the sample OFDM signal after nonlinear distortion compensation and the sample OFDM signal after filtering; Obtaining a target compensation error signal based on the nonlinear distortion compensated sample OFDM signal and the filtered sample OFDM signal; performing iterative corrections to the initial parameter set of the error compensation module based on the target compensation error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target compensation error signal is less than the set compensation error signal threshold; and taking the initial parameter set after iterative modification as the model parameter set of the error compensation module.

[0021] In one preferred embodiment, before making iterative modifications to the initial parameter set of the error compensation module based on the target compensation error signal and a preset low noise variable step size least mean square algorithm: If the absolute value of the target compensation error signal is equal to or greater than the compensation error signal threshold, the initial parameter set is used as the model parameter set of the error compensation module.

[0022] In one preferred embodiment, after obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal, Obtaining an initial OFDM signal after inverse DPD processing based on the initial OFDM signal after nonlinear distortion compensation and a conjugate parameter set corresponding to the model parameter set of the BL-DPD module; Obtaining a target distortion compensation error signal based on the initial OFDM signal after nonlinear distortion compensation and the initial OFDM signal after inverse DPD processing; The method further includes performing iterative corrections to the model parameter set based on the target distortion compensation error signal and a preset sine and error variable step size-least mean square algorithm until the absolute value of the target distortion compensation error signal is smaller than a set distortion compensation error threshold.

[0023] In one preferred embodiment, obtaining the initial OFDM signal after inverse DPD processing based on the initial OFDM signal after nonlinear distortion compensation and the conjugate parameter set corresponding to the model parameter set of the BL-DPD module includes: Sequentially performing digital-to-analog conversion, up-converting, and power amplification processing on the initial OFDM signal after nonlinear distortion compensation to obtain a power-amplified initial OFDM signal; performing power attenuation, down-conversion and analog-to-digital conversion processing on the power-amplified initial OFDM signal in order to obtain an analog-to-digital converted initial OFDM signal; and obtaining an initial OFDM signal after inverse DPD processing based on the initial OFDM signal after analog-to-digital conversion and a conjugate parameter set corresponding to the model parameter set.

[0024] In one preferred embodiment, making iterative modifications to the model parameter set based on the target distortion compensation error signal and a preset sine and error variable step size-least mean square algorithm includes: Each time you modify a set of model parameters, Obtaining sample OFDM signals after nonlinear distortion compensation corresponding to each of a plurality of historical time points adjacent to the current initial OFDM signal after nonlinear distortion compensation; obtaining an average value of the distortion compensation error signals at the current time of the initial OFDM signal after nonlinear distortion compensation based on the historical distortion compensation error signals corresponding to the plurality of sample OFDM signals after nonlinear distortion compensation; Obtaining a second target step size factor based on an error term corresponding to an average value of the distortion compensation error signal, a target distortion compensation error signal at the current time, and a history distortion compensation error signal at a history time immediately preceding the current time; The method includes modifying the model parameter set at the current time based on the second target step size factor, the conjugate distortion compensation error signal corresponding to the target distortion compensation error signal at the current time, and the initial OFDM signal after analog-to-digital conversion, to obtain the modified model parameter set, and executing the modified model parameter set.

[0025] In one preferred embodiment, the method for compensating for nonlinear distortion of a signal comprises the steps of: The method further includes performing iterative modifications to the model parameter set of the BL-DPD module based on the set cycle time.

[0026] In a second aspect, an embodiment of the present disclosure further provides a nonlinear compensation fusion model, the nonlinear compensation fusion model comprising: a BL-DPD module, a BL-CFR module, and an error compensation module; The BL-DPD module, BL-CFR module, and error compensation module are connected in parallel, and the BL-DPD module and the BL-CFR module each use the same basis functions. The error compensation module is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module.

[0027] In one preferred embodiment, the basis functions used by each of the BL-DPD and BL-CFR modules are the same.

[0028] In one preferred embodiment, the nonlinear compensation fusion model is Obtain a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module based on the initial OFDM signal; The nonlinear distortion compensation signal is used to obtain an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0029] In one preferred embodiment, the nonlinear compensation fusion model further comprises: In offline mode, it is used to extract model parameter sets for the BL-DPD module, BL-CFR module and error compensation module based on a preset low-noise variable step size-least mean square algorithm.

[0030] In one preferred embodiment, the nonlinear compensation fusion model is further used to refresh a model parameter set for the nonlinear compensation fusion model in an online mode based on a preset sine and error variable step size-least mean square algorithm and a set period time.

[0031] In one preferred embodiment, the nonlinear compensation fusion model specifically comprises: In online mode, it is used to refresh the model parameter set for only the BL-DPD module in the nonlinear compensation fusion model based on the preset sine and error variable step size-least mean square algorithm and the set cycle time.

[0032] In a third aspect, an embodiment of the present disclosure further provides an OFDM communication system, the OFDM communication system comprising: the nonlinear compensation fusion model according to the second aspect; a first branch; a second branch; a third branch; and a fourth branch; The BL-DPD module and the first branch in the nonlinear compensation fusion model are used to perform iterative modification on the initial parameter set of the BL-DPD module in an offline mode to obtain a model parameter set of the BL-DPD module; The BL-CFR module and the second branch in the nonlinear compensation fusion model are used to perform iterative modification on the initial parameter set of the BL-CFR module in offline mode to obtain the model parameter set of the BL-CFR module; The nonlinear compensation fusion model and the third branch are used to perform iterative modification on the initial parameter set of the error compensation module in an offline mode to obtain a model parameter set of the error compensation module; The nonlinear compensation fusion model and the fourth branch are used to make iterative adjustments to the model parameter sets of the BL-DPD module in online mode.

[0033] In one preferred embodiment, the first branch comprises a digital-to-analog converter DAC, an up-converter, a power amplifier PA, an attenuator, a band-pass filter BPF, a down-converter, an analog-to-digital converter ADC, a training network POST-BL-DPD module, and a preset low-noise variable step size-least mean square algorithm module, arranged in sequence.

[0034] In one preferred embodiment, the second branch comprises a CFR module, a training network POST-BL-DPD module, and a preset low noise variable step size least mean square algorithm module, placed in sequence.

[0035] In one preferred embodiment, the third branch comprises a low pass filter LPF and a preset low noise variable step size least mean square algorithm module placed in sequence.

[0036] In one preferred embodiment, the fourth branch comprises a DAC, an upconverter, a PA, an attenuator, a BPF, a downconverter, an ADC, a training network POST-BL-DPD module, and a preset sine and error variable step size-least mean square algorithm module, arranged in sequence.

[0037] In a fourth aspect, an embodiment of the present disclosure provides an electronic device comprising a processor and a memory, wherein program code is stored in the memory, and when executed by the processor, the program code causes the processor to perform steps of the method for compensating for nonlinear distortion of a signal described in the first aspect above.

[0038] In a fifth aspect, an embodiment of the present disclosure provides a computer-readable storage medium including program code, which, when executed on an electronic device, causes the electronic device to perform steps of the method for compensating for nonlinear distortion of a signal according to the first aspect above.

[0039] In a sixth aspect, an embodiment of the present disclosure provides a computer program product, which, when invoked by a computer, causes the computer to perform steps of the method for compensating for nonlinear distortion of a signal according to the first aspect.

[0040] The beneficial effects of the present disclosure are as follows: In a signal nonlinear distortion compensation method provided in an embodiment of the present disclosure, a preset nonlinear compensation fusion model is used to perform DPD processing, CFR processing, and error compensation processing on an initial OFDM signal, respectively. The nonlinear distortion-compensated initial OFDM signal is then obtained based on a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module. In this way, the BL-DPD module, BL-CFR module, and error compensation module are arranged in parallel in the preset nonlinear compensation fusion model, avoiding the technical drawbacks of the prior art, in which the DPD module is applied after the CFR module, which increases the requirements for the sampling rate of the ADC / DAC in the OFDM system, increases the hardware and algorithm convergence speed, and increases the difficulty and cost of system implementation. This effectively reduces the requirements for the ADC / DAC sampling rate and improves the DPD compensation ability for power amplifier nonlinearities, thereby further improving the communication and sensing capabilities of the OFDM system.

[0041] Additional features and advantages of the present disclosure will be set forth in the specification which follows, and in part will be obvious from the specification, or may be learned by the practice of the present disclosure. The objectives and other advantages of the present disclosure may be realized and obtained by the structure particularly pointed out in the written specification, claims, and drawings. [Brief explanation of the drawings]

[0042] In order to more clearly describe the technical means according to the embodiments of the present disclosure, the drawings necessary for the embodiments will be briefly described below. However, the drawings described below are merely a part of the embodiments of the present disclosure, and it is obvious that a person skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0043] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of an OFDM communication system provided in an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic diagram illustrating the implementation flow of a method for compensating for nonlinear distortion of a signal provided in an embodiment of the present disclosure. [Figure 3] FIG. 3 is a logic diagram for processing an initial OFDM signal provided in an embodiment of the present disclosure. [Figure 4] FIG. 4 is a flow diagram of a method for obtaining a model parameter set of a BL-DPD module provided in an embodiment of the present disclosure. [Figure 5] FIG. 5 is a logic schematic diagram of obtaining a sample OFDM signal after inverse DPD processing provided in an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic implementation flow diagram of a method for modifying an initial parameter set in offline mode provided in an embodiment of the present disclosure. [Figure 7] FIG. 7 is a flow diagram of a method for obtaining a model parameter set of a BL-CFR module provided in an embodiment of the present disclosure. [Figure 8] FIG. 8 is a flow diagram of a method for obtaining a model parameter set of an error compensation module provided in an embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic diagram of the implementation flow of the method for modifying a model parameter set in online mode provided in an embodiment of the present disclosure. [Figure 10] FIG. 10 is a logic schematic diagram of obtaining an initial OFDM signal after inverse DPD processing provided in an embodiment of the present disclosure. [Figure 11] FIG. 11 is a detailed implementation flow diagram based on FIG. 9 provided in an embodiment of the present disclosure. [Figure 12] FIG. 12 is a schematic diagram illustrating the configuration of an electronic device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0044] In order to clarify the purpose, technical means and advantages of the embodiments of the present disclosure, the technical means of the present disclosure will be clearly described in detail below with reference to the drawings in the embodiments of the present disclosure. It is clear that the described embodiments are only a part of the embodiments of the technical means of the present disclosure, and are not all of the embodiments. Based on the embodiments described in the present disclosure, those skilled in the art can obtain all other embodiments without creative efforts, all of which fall within the protection scope of the technical means of the present disclosure.

[0045] In the description of the present disclosure, "plurality" is understood to mean "at least two." The term "and / or" is only used to describe the associative relationship of related objects and indicates the existence of three types of relationships. For example, A and / or B can indicate three situations: A exists alone, A and B exist simultaneously, and B exists alone. A connection to B can indicate two situations: A is directly connected to B and A is connected to B via C. In the description of the present disclosure, terms such as "first," "second," etc. are used for distinction purposes only and do not express or imply relative importance or order.

[0046] First, the design concept of the embodiments of the present disclosure will be briefly described below. OFDM technology is a multi-carrier modulation technology that divides a carrier into multiple mutually orthogonal subcarriers to solve frequency selective fading and narrowband interference. As a result, OFDM signals are the communication signals of the global 5G standard (5G NR, 5th Generation Mobile Networks New Radio) based on the new OFDM air interface design, which allows for more options for time slots, subcarriers, etc. included in each subframe, making it applicable not only to different communication scenarios but also to different sensing scenarios.

[0047] Therefore, signals modulated using OFDM technology, i.e., OFDM signals, usually have characteristics such as non-stationary envelope, wide (frequency) bandwidth, and high PAPR. However, when an OFDM signal passes through a PA, nonlinear distortion inevitably occurs.

[0048] Initially, to ensure good linearity of the signal output from the power amplifier, simple power back-off methods were usually used, but this method reduced the efficiency of the power amplifier and wasted resources.To improve the efficiency of the power amplifier, the power amplifier was usually operated near its saturation point, which caused severe in-band distortion, increased the bit error rate of the communication system, and also caused out-of-band spectrum spreading and adjacent channel interference.

[0049] Currently, to improve the effects of nonlinear distortion in PAs, the advantages of CFR and DPD technologies can be utilized to combine them, which can simultaneously satisfy the application needs and objectives of improving power amplifier efficiency and linearity index.

[0050] Specifically, in conventional techniques combining CFR and DPD technologies, the DPD module is typically applied after the CFR module. However, when the CFR and DPD modules are cascaded, the DPD module is applied after the CFR module. Therefore, even if the signal passes through the CFR module and is peak-clipped to reduce PAPR, the PARA increases again after passing through the DPD module. However, due to the nonlinearity of the power amplifier, the output signal suffers from spectral spreading. Therefore, when implementing DPD, the bandwidth of the feedback receiving channel must be three to five times the bandwidth of the input signal. For a bandwidth of 400 MHz or higher, the ADC sampling rate in the feedback receiving channel must be at least 4 Gbps. Such a high-speed sampling ADC not only requires high requirements for hardware and algorithm convergence speed, but also increases the difficulty and cost of system implementation.

[0051] In view of this, the sampling rate of the ADC / DAC can be effectively reduced, and the suppression impact of peak clipping (CFR) on the DPD effect can be minimized as much as possible, so that 5G To improve the communication and sensing capabilities of NR (e.g., OFDM systems), an embodiment of the present disclosure provides a nonlinear distortion compensation method, which specifically includes: inputting an OFDM signal into a preset nonlinear compensation fusion model, which includes a BL-DPD module, a BL-CFR module, and an error compensation module, and the error compensation module is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module; and, for the initial OFDM signal, respectively obtaining a first OFDM signal processed by the BL-DPD module, a second OFDM signal processed by the BL-CFR module, and a third OFDM signal processed by the error compensation module; and finally, obtaining the initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0052] In particular, preferred embodiments of the present disclosure will be described below with reference to the drawings in the specification. The preferred embodiments described herein are used only to explain and interpret the present disclosure, and are not intended to limit the present disclosure. It is understood that the embodiments of the present disclosure and the features in the embodiments can be combined unless they are inconsistent.

[0053] As shown in FIG. 1, FIG. 1 is a schematic diagram of the configuration of an OFDM communication system provided in an embodiment of the present disclosure, and the OFDM communication system includes a nonlinear compensation fusion model, a first branch, a second branch, a third branch, and a fourth branch.

[0054] The nonlinear compensation fusion model includes a BL-DPD module, a BL-CFR module, and an error compensation module ECM, where the BL-DPD module, the BL-CFR module, and the error compensation module ECM are connected in parallel, and the error compensation module ECM is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module.

[0055] Preferably, the basis functions used by each of the BL-DPD module and the BL-CFR module are the same.

[0056] The first branch includes a DAC, an up-converter, a PA, an attenuator 1 / G, a band pass filter (BPF), a down-converter, an ADC, a training network POST-BL-DPD module, and a preset Low Noise Variable Step Size-Least Mean Square (LNVSS-LMS) algorithm module, which are arranged in sequence.

[0057] The second branch includes a CFR module, a training network POST-BL-DPD module, and a preset low-noise variable step size-least mean square algorithm module, which are arranged in sequence.

[0058] The third branch comprises a Low Pass Filter (LPF) and a preset low noise variable step size least mean square algorithm module, which are arranged in sequence.

[0059] The fourth branch includes a DAC, an upconverter, a PA, an attenuator 1 / G, a BPF, a downconverter, an ADC, a training network POST-BL-DPD module, and a preset Sine and Error Variable Step Size-Least Mean Square (SEVSS-LMS) algorithm module, which are arranged in sequence.

[0060] As described above, the difference between the first and fourth branches is that the first branch uses the LNVSS-LMS algorithm, while the fourth branch simply uses the SEVSS-LMS algorithm. The LNVSS-LMS algorithm adjusts the step-size factor function based on parameters such as the error energy at the current time, the absolute error energy of the error at the previous time, and the average value. This effectively reduces the step-size factor function's susceptibility to noise, improving the LNVSS-LMS algorithm's noise reduction capabilities and adjusting the parameter value to be smaller than the current error value, thereby achieving a smaller step size and a smaller steady-state error. The SEVSS-LMS algorithm controls the variable step-size factor function by adjusting three parameters. Therefore, in the early stage when the error signal is large, the variable step-size factor function automatically increases the step size, resulting in a faster convergence speed. Once the steady state is reached, the variable step-size factor function can maintain a small step size, resulting in a slower convergence speed and a smaller error.

[0061] The nonlinear compensation fusion model is also called a compensation band limited-crest factor reduction-digital predistortion (CFR-DPD, CBL-CFR-DPD) model.

[0062] In addition, the first branch, the second branch, and the third branch can share the same preset low-noise variable step-size least mean square algorithm module to reduce the overhead of the electrical circuit. Note that the embodiment of the present disclosure does not limit the number of preset low-noise variable step-size least mean square algorithm modules.

[0063] In an embodiment of the present disclosure, the nonlinear compensation fusion model is used to perform DPD processing, CFR processing, and error compensation processing on the initial OFDM signal, respectively, to obtain a first OFDM signal processed by the BL-DPD module, a second OFDM signal processed by the BL-CFR module, and a third OFDM signal processed by the error compensation module, thereby obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0064] The BL-DPD module and the first branch in the nonlinear compensation fusion model are used to iteratively modify the initial parameter set of the BL-DPD module in offline mode to obtain the model parameter set of the BL-DPD module, that is, to extract the kernel parameters of the BL-DPD module in offline mode, where offline mode refers to not receiving the initial OFDM signal, i.e., module / model (pre-) training mode.

[0065] The BL-CFR module and the second branch in the nonlinear compensation fusion model are used to perform iterative modification on the initial parameter set of the BL-CFR module in offline mode to obtain the model parameter set of the BL-CFR module, that is, to extract the kernel parameters of the BL-CFR module in offline mode.

[0066] The nonlinear compensation fusion model and the third branch are used to perform iterative modification on the initial parameter set of the error compensation module ECM in offline mode to obtain the model parameter set of the error compensation module ECM, that is, to extract the kernel parameters of the error compensation module ECM in offline mode.

[0067] The nonlinear compensation fusion model and the fourth branch are used to iteratively modify the model parameter set of the BL-DPD module in online mode, that is, to effectively refresh the parameters of the nonlinear compensation fusion model (i.e., the CBL-CFR-DPD model) in online mode, thereby ultimately ensuring the post-cascading pre-distortion of the entire OFDM communication system, effectively improving the nonlinear distortion of the power amplifier of the OFDM signal, and improving the efficiency of the entire OFDM communication system. Here, the online mode refers to receiving an initial OFDM signal, i.e., the real-time operation mode.

[0068] Preferably, the nonlinear compensation fusion model is further used to extract model parameter sets for the BL-DPD module, the BL-CFR module, and the error compensation module based on a preset low-noise variable step size-least mean squares algorithm in an offline mode, and / or to refresh model parameter sets for the nonlinear compensation fusion model based on a preset sine and error variable step size-least mean squares algorithm and a set cycle time in an online mode. Preferably, the nonlinear compensation fusion model is specifically used to refresh model parameter sets for only the BL-DPD module in the nonlinear compensation fusion model based on a preset sine and error variable step size-least mean squares algorithm and a set cycle time in an online mode.

[0069] It should be noted that the Mode in FIG. 1 is understood as a state selection module, and the corresponding state may be offline mode or online mode.

[0070] Based on the above-mentioned OFDM communication system, a new nonlinear compensation fusion model (i.e., a CBL-CFR-DPD integrated model) is constructed. The BL-DPD module and the BL-CFR module are integrated into one model using an error compensation module (ECM). By utilizing an "offline + online" mechanism for extracting and refreshing the parameters of each module (i.e., model parameter set), the order of the band-limiting filter can be effectively reduced, reducing the complexity of the entire nonlinear compensation fusion model while ensuring the accuracy of the entire nonlinear compensation fusion model. In offline mode, the parameters of the BL-DPD module, BL-CFR module, and ECM module are extracted and corrected based on the LNVSS-LMS self-adaptive algorithm. In online mode, the parameters of only the BL-DPD module are effectively refreshed and corrected based on the SEVSS-LMS self-adaptive algorithm. In addition, compared to a system that only implements a DPD module, the nonlinear compensation fusion model requires more addition and subtraction operations of several coefficients, but the execution complexity of both is approximately the same. Compared with the conventional technical means that apply a CFR module and a DPD module independently, the execution complexity is reduced, and the compensation ability of the digital predistorter for the nonlinearity of a wideband power amplifier can be effectively improved.

[0071] Based on the above-mentioned OFDM communication system, a signal nonlinear distortion compensation method provided in an exemplary embodiment of the present disclosure will be described below with reference to the drawings. Note that the above system architecture is for easily understanding the spirit and principle of the present disclosure, and the embodiments of the present disclosure are not limited thereto.

[0072] Referring to FIG. 2, FIG. 2 is an implementation flow chart of a signal nonlinear distortion compensation method provided in an embodiment of the present disclosure, which is applied to the OFDM communication system. The detailed implementation flow of the method is as follows:

[0073] S201: Input the initial OFDM signal into a preset nonlinear compensation fusion model.

[0074] Here, the nonlinear compensation fusion model includes a BL-DPD module, a BL-CFR module, and an error compensation module ECM, and the error compensation module ECMH is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module.

[0075] The BL-DPD module and the BL-CFR module use the same basis functions, but different model parameter sets (i.e., coefficients).

[0076] S202: For the initial OFDM signal, respectively obtain a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module.

[0077] 3 , in step S202, the nonlinear compensation fusion model modulates the initial OFDM signal based on the model parameter sets converged in the offline modes of the BL-DPD module, the BL-CFR module, and the error compensation module ECM to obtain the first, second, and third OFDM signals, respectively. The offline mode refers to the absence of the initial OFDM signal. This method processes the initial OFDM signal using three parallel modules, effectively avoiding the technical drawbacks of the prior art, in which the DPD module is applied after the CFR module, which increases the sampling rate of the ADC / DAC in OFDM systems and the requirements for hardware and algorithm convergence speed, thereby increasing the system implementation difficulty and cost.

[0078] JPEG2026500061000002.jpg37170

[0079] JPEG2026500061000003.jpg29170

[0080] JPEG2026500061000004.jpg37169

[0081] JPEG2026500061000005.jpg30170

[0082] JPEG2026500061000006.jpg38170

[0083] JPEG2026500061000007.jpg24170

[0084] Therefore, the model parameter set is 1. A combination of parameters consisting of the kernel coefficients, nonlinearity order, memory depth, and order of the low-order LPF of the BL-DPD module; 2. The combination of parameters consisting of the kernel coefficients, nonlinearity order, memory depth and order of the low-order LPF of the BL-CFR module; 3. A combination of parameters consisting of kernel coefficients, nonlinear order and memory depth of the error compensation module ECM; Contains one of the following:

[0085] S203: Obtain an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0086] Specifically, when step S203 is performed, the nonlinear compensation fusion model obtains the first OFDM signal processed by the BL-DPD module, the second OFDM signal processed by the BL-CFR module, and the third OFDM signal processed by the error compensation module, and then can obtain an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0087] JPEG2026500061000008.jpg63169

[0088] Note that the model parameter sets converged in the offline modes of the BL-DPD module, the BL-CFR module, and the error compensation module are obtained by the nonlinear compensation fusion model and the first branch, the nonlinear compensation fusion model and the second branch, and the nonlinear compensation fusion model and the third branch, respectively.

[0089] In one preferred embodiment, referring to FIG. 4 , when the parameter combination of the model parameter set consists of the kernel coefficient of the BL-DPD module, the nonlinear order, the memory depth, and the order of the low-order LPF, the model parameter set is obtained as follows:

[0090] S401: A sample OFDM signal in offline mode is input to the BL-DPD module, and a sample OFDM signal after DPD processing is obtained.

[0091] For example, when step S401 is performed, assuming that the sample OFDM signal in offline mode is s(n), the kernel processing of the BL-DPD module is performed to obtain the sample OFDM signal x(n) after DPD processing.

[0092] S402: Obtain a sample OFDM signal after inverse DPD processing based on the sample OFDM signal after DPD processing and a conjugate parameter set corresponding to the initial parameter set of the BL-DPD module.

[0093] In a preferred embodiment, referring to FIG. 5 , when step S402 is performed, the OFDM communication system obtains a post-DPD ​​sample OFDM signal, and then, through a first branch in offline mode, sequentially performs digital-to-analog conversion, up-converting, and power amplification on the post-DPD ​​sample OFDM signal to obtain a post-power-amplified sample OFDM signal, and then sequentially performs power attenuation, down-converting, and analog-to-digital conversion on the power-amplified sample OFDM signal to obtain a post-analog-to-digital-converted sample OFDM signal, and finally, obtains a post-inverse DPD sample OFDM signal based on the post-analog-to-digital-converted sample OFDM signal and a conjugate parameter set corresponding to the initial parameter set.

[0094] JPEG2026500061000009.jpg66170

[0095] JPEG2026500061000010.jpg24169

[0096] JPEG2026500061000011.jpg35170

[0097] S403: Obtain a target DPD error signal based on the sampled OFDM signal in the offline mode and the sampled OFDM signal after the inverse DPD processing.

[0098] JPEG2026500061000012.jpg23170

[0099] JPEG2026500061000013.jpg13169

[0100] S404: Based on the target DPD error signal and a preset low-noise variable step size-least mean square algorithm, iteratively modify the initial parameter set until the absolute value of the target DPD error signal is smaller than the set DPD error signal threshold.

[0101] JPEG2026500061000014.jpg57169

[0102] JPEG2026500061000015.jpg25170

[0103] S601: Obtain sample OFDM signals corresponding to each of a plurality of historical time points adjacent to the current sample OFDM signal in offline mode.

[0104] Illustratively, when step S601 is performed, the OFDM communication system obtains sample OFDM signals s(i) corresponding to each of a plurality of historical time points adjacent to the current sample OFDM signal s(n) in offline mode, for example, obtaining the first N sample OFDM signals s(i), where i is an integer ∈ (1, N).

[0105] S602: Based on the historical DPD error signals corresponding to each of the plurality of sampled OFDM signals, obtain an average value of the DPD error signals at the current time of the sampled OFDM signals in the offline mode.

[0106] JPEG2026500061000016.jpg25169

[0107] JPEG2026500061000017.jpg13170

[0108] S603: A first target step size factor is obtained based on the average value of the DPD error signal, the step size factor at the previous historical time point adjacent to the current time point, the target DPD error signal at the current time point, and the historical DPD error signal at the previous historical time point.

[0109] JPEG2026500061000018.jpg23170

[0110] JPEG2026500061000019.jpg70170

[0111] The above α and β are preset according to the actual situation, and the calculation formula for the first target step size factor can be used as the update formula for the first target step size factor.

[0112] S604: Based on the first target step size factor, the conjugate DPD error signal corresponding to the target DPD error signal at the current time, and the sampled OFDM signal after analog-to-digital conversion, the initial parameter set at the current time is modified to obtain a modified initial parameter set.

[0113] JPEG2026500061000020.jpg23170

[0114] JPEG2026500061000021.jpg36170

[0115] It is apparent that the method described in the above steps S601 to S604 realizes iterative modification of the initial parameter set in offline mode, so that the BL-DPD module completes nonlinear distortion compensation for the initial OFDM signal according to a more accurate model parameter set.

[0116] S405: The initial parameter set after iterative modification is set as the model parameter set of the BL-DPD module.

[0117] Specifically, when step S405 is performed, if it is determined that the absolute value of the current target DPD error signal is smaller than the set DPD error signal threshold, the initial parameter set after iterative modification at this time can be used as the model parameter set of the BL-DPD module, and the model parameter set can be assigned to the BL-DPD module.

[0118] Preferably, before performing step S404, if the absolute value of the target DPD error signal is equal to or greater than the DPD error signal threshold, the initial parameter set is directly used as the model parameter set of the BL-DPD module.

[0119] Therefore, in the OFDM communication system, the method described in steps S401 to S405 selects the Mode as offline mode, processes the sample OFDM signal using the nonlinear compensation fusion model and the first branch, and uses the LNVSS-LMS self-adaptive algorithm to train the POST-BL-DPD module, thereby realizing the modification and extraction of the model parameter set of the BL-DPD module.

[0120] In one preferred embodiment, referring to FIG. 7, when the parameter combination of the model parameter set consists of the kernel coefficient of the BL-CFR module, the nonlinear order, the memory depth and the order of the low-order LPF, the model parameter set is obtained as follows:

[0121] S701: A sample OFDM signal in offline mode is input to a BL-DPD module and a preset CFR module in order to obtain a sample OFDM signal after DPD-CFR processing.

[0122] For example, when step S701 is performed, assuming that the sample OFDM signal in offline mode is s(n), a post-DPD ​​processed sample OFDM signal x(n) is obtained through kernel processing of the BL-DPD module, and the post-DPD ​​processed sample OFDM signal x(n) is processed by a preset CFR module to obtain a post-DPD-CFR processed sample OFDM signal x_c(n).

[0123] S702: Obtain a sample OFDM signal after CFR processing based on the sample OFDM signal in the offline mode and a conjugate parameter set corresponding to the initial parameter set of the BL-CFR module.

[0124] JPEG2026500061000022.jpg23170

[0125] JPEG2026500061000023.jpg35169

[0126] JPEG2026500061000024.jpg48170

[0127] JPEG2026500061000025.jpg8170

[0128] S703: Obtain a target CFR error signal based on the sample OFDM signal after DPD-CFR processing and the sample OFDM signal after CFR processing.

[0129] JPEG2026500061000026.jpg23169

[0130] JPEG2026500061000027.jpg18170

[0131] S704: Based on the target CFR error signal and a preset low-noise variable step size-least mean square algorithm, iteratively modify the initial parameter set until the absolute value of the target CFR error signal is smaller than the set CFR error signal threshold.

[0132] JPEG2026500061000028.jpg58169

[0133] JPEG2026500061000029.jpg38170

[0134] S705: The initial parameter set after iterative modification is set as the model parameter set of the BL-CFR module.

[0135] Specifically, when step S705 is executed, if it is determined that the absolute value of the current target CFR error signal is smaller than the set CFR error signal threshold, the initial parameter set after iterative modification at this time can be used as the model parameter set of the BL-CFR module, and the model parameter set can be assigned to the BL-CFR module.

[0136] Preferably, before performing step 704, if the absolute value of the target CFR error signal is equal to or greater than the CFR error signal threshold, the initial parameter set is directly taken as the model parameter set for the BL-CFR module.

[0137] Therefore, based on the method described in the above steps S701 to S705, in the OFDM communication system, the Mode is selected as the offline mode, the sample OFDM signal is processed using the nonlinear compensation fusion model and the second branch, and the LNVSS-LMS self-adaptive algorithm is used to train the POST-BL-CFR module, thereby realizing the modification and extraction of the model parameter set of the BL-CFR module.

[0138] In one preferred embodiment, referring to FIG. 8, when the parameter combination of the model parameter set consists of the kernel coefficient, the nonlinearity order and the memory depth of the error compensation module ECM, the model parameter set is obtained as follows:

[0139] S801: A sample OFDM signal in offline mode is input to a nonlinear compensation fusion model and a preset high-order LPF, respectively, to obtain a sample OFDM signal after nonlinear distortion compensation and a sample OFDM signal after filtering processing.

[0140] It should be noted that when obtaining the model parameter set of the error compensation module ECM, ie, when performing the method described in steps S801 to S804, the sample OFDM signal in the offline mode is small, ie, has a small width, and is in the linear region of the PA.

[0141] To reduce the complexity of the model, the BL-DPD module and the BL-CFR module are generated by low-order FIR processing. To compensate for the signal loss caused by the low-order FIR, the error compensation parameters are trained offline using high-order FIR, effectively reducing the order of the band-limited FIR. This reduces the complexity of the entire nonlinear distortion fusion model while ensuring the accuracy and performance of the entire model.

[0142] JPEG2026500061000030.jpg28170

[0143] JPEG2026500061000031.jpg73170

[0144] JPEG2026500061000032.jpg30169

[0145] Here, h represents the coefficient of the preset high-order LPF, and L' represents the order of the preset high-order LPF, and preferably, the order L' is 91 or greater.

[0146] S802: Obtain a target compensation error signal based on the sample OFDM signal after nonlinear distortion compensation and the sample OFDM signal after filtering.

[0147] JPEG2026500061000033.jpg24170

[0148] JPEG2026500061000034.jpg19170

[0149] S803: Based on the target compensation error signal and a preset low-noise variable step size-least mean square algorithm, iteratively adjust the initial parameter set of the error compensation module until the absolute value of the target compensation error signal is smaller than the set compensation error signal threshold.

[0150] JPEG2026500061000035.jpg58169

[0151] JPEG2026500061000036.jpg35170

[0152] S804: The initial parameter set after iterative correction is set as the model parameter set of the error compensation module.

[0153] Specifically, when step S804 is performed, if it is determined that the absolute value of the current target compensation error signal is smaller than the set compensation error signal threshold, the initial parameter set after iterative modification at this time can be used as the model parameter set of the error compensation module ECM, and the model parameter set can be assigned to the error compensation module ECM.

[0154] Preferably, before performing step S804, if the absolute value of the target compensation error signal is equal to or greater than the threshold value of the compensation error signal, the initial parameter set is directly taken as the model parameter set of the error compensation module ECM.

[0155] Therefore, based on the method described in the above steps 801 to S804, in the OFDM communication system, the Mode is selected as offline mode, the sample OFDM signal is processed using the nonlinear compensation fusion model and the third branch, and the LNVSS-LMS self-adaptive algorithm is used to train the CBL-CFR-DPD module, thereby realizing the modification and extraction of the model parameter set of the error compensation module ECM.

[0156] Furthermore, referring to FIG. 9 , after the OFDM communication system obtains the initial OFDM signal after nonlinear distortion compensation through the nonlinear compensation fusion model, it can further refresh / modify the model parameter set of the BL-DPD module, and the specific operation flow is as follows:

[0157] S901: Obtain an initial OFDM signal after inverse DPD processing based on the initial OFDM signal after nonlinear distortion compensation and a conjugate parameter set corresponding to the model parameter set of the BL-DPD module.

[0158] In one preferred embodiment, referring to FIG. 10 , the OFDM communication system obtains a post-nonlinear distortion compensation initial OFDM signal, and then, through a fourth branch in online mode, sequentially performs digital-to-analog conversion, up-converting, and power amplification processing on the post-nonlinear distortion compensation initial OFDM signal to obtain a post-power-amplified initial OFDM signal, and then sequentially performs power attenuation, down-converting, and analog-to-digital conversion processing on the power-amplified initial OFDM signal to obtain a post-analog-to-digital conversion initial OFDM signal, and finally, based on the post-analog-to-digital conversion initial OFDM signal and a conjugate parameter set corresponding to the model parameter set, obtain a post-inverse DPD processing initial OFDM signal.

[0159] JPEG2026500061000037.jpg71170

[0160] JPEG2026500061000038.jpg22170

[0161] JPEG2026500061000039.jpg46170

[0162] S902: A target distortion compensation error signal is obtained based on the initial OFDM signal after nonlinear distortion compensation and the initial OFDM signal after inverse DPD processing.

[0163] JPEG2026500061000040.jpg22170

[0164] JPEG2026500061000041.jpg19170

[0165] S903: Based on the target distortion compensation error signal and a preset sine and error variable step size-least mean square algorithm, iteratively adjust the model parameter set until the absolute value of the target distortion compensation error signal is smaller than the set distortion compensation error threshold.

[0166] JPEG2026500061000042.jpg64169

[0167] JPEG2026500061000043.jpg96170

[0168] The new CBL-CFR-DPD integrated technology utilizes an "offline + online" mechanism for extracting and refreshing module parameters, effectively improving the digital predistorter's ability to compensate for wideband PA nonlinearities. In offline mode, the extraction of module parameters is completed, effectively improving operation efficiency. In online mode, the CBL-CFR-DPD module parameters are effectively refreshed, enabling faster predistortion processing for wideband signals. The error compensation module ECM essentially integrates the BL-DPD module and BL-CFR module into a single module. While this model requires more coefficient addition and subtraction operations than a system that only uses a DPD module, the execution complexity of both modules is roughly the same, resulting in lower execution complexity than the traditional technology that uses separate CFR and DPD modules.

[0169] JPEG2026500061000044.jpg23170

[0170] S1101: Obtain sample OFDM signals after nonlinear distortion compensation corresponding to each of a plurality of historical times, adjacent to the current initial OFDM signal after nonlinear distortion compensation.

[0171] JPEG2026500061000045.jpg33170

[0172] S1102: Based on the historical distortion compensation error signals corresponding to the plurality of nonlinearly-distortion-compensated sample OFDM signals, an average value of the distortion compensation error signals at the current time of the initial OFDM signal after nonlinear distortion compensation is obtained.

[0173] JPEG2026500061000046.jpg25169

[0174] JPEG2026500061000047.jpg12168

[0175] S1103: A second target step size factor is obtained based on an error term corresponding to the average value of the distortion compensation error signal, a target distortion compensation error signal at the current time, and a history distortion compensation error signal at the history time immediately preceding the current time.

[0176] JPEG2026500061000048.jpg22169

[0177] JPEG2026500061000049.jpg52170

[0178] S1104: Based on the second target step size factor, the conjugate distortion compensation error signal corresponding to the target distortion compensation error signal at the current time, and the initial OFDM signal after analog-to-digital conversion, the model parameter set at the current time is corrected to obtain the corrected model parameter set.

[0179] JPEG2026500061000050.jpg22170

[0180] JPEG2026500061000051.jpg35169

[0181] It is apparent that, based on the method described in the above steps S1101 to S1104, iterative modification of the model parameter set of the BL-DPD module is realized in online mode, so that the BL-DPD module subsequently completes nonlinear distortion compensation for the OFDM signal according to a more accurate model parameter set.

[0182] Preferably, in online mode, the OFDM communication system can perform iterative modification to the model parameter set of the BL-DPD module based on a set period time, i.e., perform branching (i.e., nonlinear compensation fusion model and fourth branching) processing in online mode on the initial OFDM signal based on a preset period T.

[0183] Furthermore, if it is determined that the absolute value of the current target distortion compensation error signal is smaller than the set distortion compensation error threshold, the model parameter set after this iterative correction can be used as a new model parameter set for the BL-DPD module, and the model parameter set can be assigned to the BL-DPD module.

[0184] Therefore, based on the method described in steps S901 to S903 above, in the OFDM communication system, the Mode is switched to the online mode, and online branching (nonlinear compensation fusion model and fourth branching) processing is performed on the initial OFDM signal based on the preset period T, and the SEVSS-LMS self-adaptive algorithm is used to effectively refresh / modify the parameters of the nonlinear compensation fusion model (i.e., the CBL-CFR-DPD model) (i.e., the model parameter set of the BL-DPD module).

[0185] As described above, in the signal nonlinear distortion compensation method provided in the embodiment of the present disclosure, the initial OFDM signal is subjected to DPD processing, CFR processing, and error compensation processing based on a preset nonlinear compensation fusion model, thereby obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal processed by the BL-DPD module, the second OFDM signal processed by the BL-CFR module, and the third OFDM signal processed by the error compensation module.

[0186] In this way, by parallelizing the BL-DPD module, BL-CFR module, and error compensation module in the preset nonlinear compensation fusion model, it is possible to avoid the technical drawbacks of the prior art, where the DPD module is applied after the CFR module, which increases the requirements for the ADC / DAC sampling rate in the OFDM system and also increases the requirements for hardware and algorithm convergence speed, thereby increasing the difficulty and cost of system implementation. This not only effectively reduces the requirements for the ADC / DAC sampling rate, but also improves the DPD's ability to compensate for power amplifier nonlinearities, thereby further improving the communication and sensing capabilities of the OFDM system.

[0187] Based on the same inventive idea, an embodiment of the present disclosure further provides a nonlinear compensation fusion model, including a BL-DPD module, a BL-CFR module, and an error compensation module, The BL-DPD module, BL-CFR module, and error compensation module are connected in parallel, and the BL-DPD module and the BL-CFR module each use the same basis functions. The error compensation module is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module.

[0188] In one preferred embodiment, the basis functions used by each of the BL-DPD and BL-CFR modules are the same.

[0189] In one preferred embodiment, the nonlinear compensation fusion model is Obtain a first OFDM signal processed by a BL-DPD module, a second OFDM signal processed by a BL-CFR module, and a third OFDM signal processed by an error compensation module based on the initial OFDM signal; The nonlinear distortion compensation signal is used to obtain an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal.

[0190] In one preferred embodiment, the nonlinear compensation fusion model further comprises: In offline mode, it is used to extract model parameter sets for the BL-DPD module, the BL-CFR module and the error compensation module based on a preset low-noise variable step size-least mean square algorithm.

[0191] In one preferred embodiment, the nonlinear compensation fusion model further comprises: In online mode, it is used to refresh the model parameter set for the nonlinear compensation fusion model based on the preset sine and error variable step size-least mean square algorithm and the set cycle time.

[0192] In one preferred embodiment, the nonlinear compensation fusion model specifically comprises: In online mode, it is used to refresh the model parameter set for only the BL-DPD module in the nonlinear compensation fusion model based on the preset sine and error variable step size-least mean square algorithm and the set cycle time.

[0193] Based on the same inventive idea, an embodiment of the present disclosure provides an OFDM communication system, including a nonlinear compensation fusion model, a first branch, a second branch, a third branch, and a fourth branch; The BL-DPD module and the first branch in the nonlinear compensation fusion model are used to perform iterative modification on the initial parameter set of the BL-DPD module in an offline mode to obtain a model parameter set of the BL-DPD module; The BL-CFR module and the second branch in the nonlinear compensation fusion model are used to perform iterative modification on the initial parameter set of the BL-CFR module in offline mode to obtain the model parameter set of the BL-CFR module; The nonlinear compensation fusion model and the third branch are used to perform iterative modification on the initial parameter set of the error compensation module in an offline mode to obtain a model parameter set of the error compensation module; The nonlinear compensation fusion model and the fourth branch are used to make iterative adjustments to the model parameter sets of the BL-DPD module in online mode.

[0194] In one preferred embodiment, the first branch comprises a digital-to-analog converter DAC, an up-converter, a power amplifier PA, an attenuator, a band-pass filter BPF, a down-converter, an analog-to-digital converter ADC, a training network POST-BL-DPD module, and a preset low-noise variable step size-least mean square algorithm module, arranged in sequence.

[0195] In one preferred embodiment, the second branch comprises a CFR module, a training network POST-BL-DPD module, and a preset low noise variable step size least mean square algorithm module, placed in sequence.

[0196] In one preferred embodiment, the third branch comprises a low pass filter LPF and a preset low noise variable step size least mean square algorithm module placed in sequence.

[0197] In one preferred embodiment, the fourth branch comprises a DAC, an upconverter, a PA, an attenuator, a BPF, a downconverter, an ADC, a training network POST-BL-DPD module, and a preset sine and error variable step size-least mean square algorithm module, arranged in sequence.

[0198] Based on the same technical idea, an embodiment of the present disclosure further provides an electronic device, which can implement the steps of the signal nonlinear distortion compensation method provided in the above embodiment of the present disclosure. In one embodiment, the electronic device may be a server, a terminal device, or other electronic devices. Referring to FIG. 12, the electronic device includes: The system includes at least one processor 1201 and a memory 1202 connected to the at least one processor 1201. In the embodiments of the present disclosure, the specific connection medium between the processor 1201 and the memory 1202 is not limited. In FIG. 12, the processor 1201 and the memory 1202 are connected by a bus 1200. The bus 1200 is shown in FIG. 12 with a thick line, and the connection method between other components is merely a schematic illustration and is not intended to be limiting. The bus 1200 can be divided into an address bus, a data bus, a control bus, etc. For convenience of illustration, only one thick line is shown in FIG. 12, but this does not mean that there is only one bus or only one type of bus. Alternatively, the processor 1201 may be called a controller, and the name is not limited.

[0199] In an embodiment of the present disclosure, the memory 1202 stores instructions executable by the at least one processor 1201, and the at least one processor 1201 can perform the above-mentioned signal nonlinear distortion compensation method by executing the instructions stored in the memory 1202. The processor 1201 can realize the functions of each module in the corresponding device.

[0200] Here, processor 1201 is the control center of the device, and connects each part of the entire control device via various interfaces and lines, runs or executes instructions stored in memory 1202, and can monitor the entire device by calling up data stored in memory 1202 (each function and processing data of the device).

[0201] In one possible design, processor 1201 may include one or more processing units, and processor 1201 may integrate an application processor and a modem processor, where the application processor primarily handles the operating system, user interface, applications, etc., and the modem processor primarily handles wireless communications. It is understood that the modem processor need not be integrated into processor 1201. In some embodiments, processor 1201 and memory 1202 may be implemented on the same chip, and in some embodiments, they may each be implemented on separate chips.

[0202] The processor 1201 may be a general-purpose processor such as a CPU, a digital signal processing device, a dedicated integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present disclosure. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the method for compensating for nonlinear distortion of a signal disclosed in connection with the embodiments of the present disclosure may be executed directly by a hardware processor, or may be executed by a combination of hardware modules and software modules in the processor.

[0203] The memory 1202 may be used as a non-volatile computer-readable storage medium to store non-volatile software programs, non-volatile computer-executable programs, and modules. The memory 1202 may include at least one type of storage medium, such as flash memory, a hard disk, a multimedia card, a card memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, a magnetic disk, an optical disk, etc. The memory 1202 may be any medium that carries or stores desired program code in the form of instructions or data structures and is accessible by a computer, but is not limited to such. The memory 1202 in the embodiments of the present disclosure may be a circuit for storing program instructions and / or data, or any other device capable of implementing memory functions.

[0204] By designing and programming the processor 1201, a code corresponding to the signal nonlinear distortion compensation method described in the above embodiment can be written into the chip, so that when the chip runs, it can perform the steps of the signal nonlinear distortion compensation method according to the embodiment shown in Fig. 2. The method of designing and programming the processor 1201 is well known to those skilled in the art, and therefore will not be described here.

[0205] Based on the same inventive idea, an embodiment of the present disclosure further provides a storage medium, in which computer instructions are stored, and when the computer instructions are executed on a computer, the computer performs the above-mentioned method for compensating nonlinear distortion of a signal.

[0206] In some preferred embodiments, the present disclosure further provides a program product capable of realizing each aspect of the method for compensating for nonlinear distortion of a signal, the program product including program code, which, when the program product is executed on an apparatus, causes the control device to execute steps of the method for compensating for nonlinear distortion of a signal according to each exemplary embodiment of the present disclosure described herein.

[0207] Although the above detailed description refers to several units or sub-units of the device, such division is merely exemplary and not mandatory. In fact, according to embodiments of the present disclosure, features and functions of two or more units described above may be embodied in one unit. Conversely, features and functions of one unit described above may be embodied by multiple units.

[0208] Furthermore, although the figures describe the operations of the methods of the present disclosure in a particular order, this does not require or imply that the operations must be performed in that particular order, or that all operations must be performed to achieve desired results. Additionally or preferably, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be divided into multiple steps.

[0209] Those skilled in the art should understand that the embodiments of the present disclosure may provide a method, a system, or a computer program product. The present disclosure may be realized as hardware, software, or a combination of hardware and software. The present disclosure may also be realized as a computer program product executable on one or more computer-usable storage media (including, but not limited to, disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0210] The present disclosure has been described with reference to flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, are implemented by computer program instructions. To generate a server, these computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a server, whereby the instructions executed by the processor of the computer or other programmable data processing device can generate a device for implementing the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0211] Program code for carrying out operations of the present disclosure may be written using any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and the like, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may execute entirely on the user computing device, partially on the user device, as a separate package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0212] When referring to a remote computing device, the remote computing device may be connected to the user computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., connected via the Internet via an Internet Service Provider).

[0213] These computer program instructions can be stored in a computer-readable memory that can cause a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device that implements the functions specified in one or more flows of the flowcharts and / or one or more blocks of the block diagrams.

[0214] These computer program instructions can be loaded into a computer or other programmable data processing apparatus and execute a series of operational steps on the computer or other programmable device to generate a computer-implemented process, whereby the instructions executing on the computer or other programmable device provide steps for implementing the functions specified in one or more flows of the flowcharts and / or one or more blocks of the block diagrams.

[0215] It is obvious to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A method for compensating for nonlinear distortion of a signal, comprising: inputting an initial orthogonal frequency division multiplexing OFDM signal into a preset nonlinear compensation fusion model, the nonlinear compensation fusion model comprising a frequency band limited digital predistortion (BL-DPD) module, a frequency band limited crest factor reduction (BL-CFR) module, and an error compensation module, the error compensation module performing error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module; For an initial OFDM signal, respectively obtain a first OFDM signal processed by the BL-DPD module, a second OFDM signal processed by the BL-CFR module, and a third OFDM signal processed by the error compensation module; and obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal. A method for compensating for nonlinear signal distortion.

2. The BL-DPD module and the BL-CFR module each use the same basis function. The method for compensating for nonlinear distortion of a signal according to claim 1 .

3. respectively obtaining, for the initial OFDM signal, a first OFDM signal processed by the BL-DPD module, a second OFDM signal processed by the BL-CFR module, and a third OFDM signal processed by the error compensation module; modulating the initial OFDM signal based on model parameter sets converged in the offline modes of the BL-DPD module, the BL-CFR module, and the error compensation module, to obtain the first OFDM signal, the second OFDM signal, and the third OFDM signal, respectively. The method for compensating for nonlinear distortion of a signal according to claim 1 .

4. The model parameter set is a combination of parameters including a kernel coefficient, a nonlinearity order, a memory depth, and an order of a low-order low-pass filter (LPF) of the BL-DPD module; A combination of parameters consisting of a kernel coefficient, a nonlinearity order, a memory depth, and an order of a low-order LPF of the BL-CFR module; a combination of parameters including kernel coefficients, nonlinearity order, and memory depth of the error compensation module; characterized in that it comprises any one of The method for compensating for nonlinear distortion of a signal according to claim 3.

5. When the parameter combination of the model parameter set includes the kernel coefficient, the nonlinearity order, the memory depth, and the order of the low-order LPF of the BL-DPD module, the model parameter set is inputting a sample OFDM signal in offline mode into the BL-DPD module to obtain a sample OFDM signal after DPD processing; obtaining an inverse DPD sampled OFDM signal based on the DPD sampled OFDM signal and a conjugate parameter set corresponding to an initial parameter set of the BL-DPD module; obtaining a target DPD error signal based on the sampled OFDM signal in the offline mode and the sampled OFDM signal after the inverse DPD processing; performing iterative modifications to the initial parameter set based on the target DPD error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target DPD error signal is less than a preset DPD error signal threshold; and setting the initial parameter set after iterative modification as the model parameter set of the BL-DPD module. The method for compensating for nonlinear distortion of a signal according to claim 4.

6. Obtaining an inverse DPD processed sample OFDM signal based on the DPD processed sample OFDM signal and a conjugate parameter set corresponding to an initial parameter set of the BL-DPD module, performing digital-to-analog conversion, up-converting, and power amplification on the sample OFDM signal after the DPD processing, to obtain a sample OFDM signal after power amplification; performing power attenuation, down-converting, and analog-to-digital conversion processing on the power-amplified sample OFDM signal in order to obtain an analog-to-digital converted sample OFDM signal; and obtaining the inverse DPD processed sample OFDM signal based on the analog-to-digital converted sample OFDM signal and a conjugate parameter set corresponding to the initial parameter set. The method for compensating for nonlinear distortion of a signal according to claim 5.

7. Iteratively modifying the initial parameter set based on the target DPD error signal and a preset low-noise variable step size-least mean square algorithm includes, each time modifying the initial parameter set, obtaining sample OFDM signals corresponding to each of a plurality of historical time points adjacent to the current sample OFDM signal in the offline mode; obtaining an average value of the DPD error signals at a current time of the sampled OFDM signals in the offline mode based on historical DPD error signals corresponding to each of a plurality of sampled OFDM signals; obtaining a first target step size factor based on an average value of the DPD error signal, a step size factor at a time in history immediately preceding the current time, a target DPD error signal at the current time, and a historical DPD error signal at the time in history immediately preceding the current time; modifying an initial parameter set at the current time based on the first target step size factor, a conjugate DPD error signal corresponding to the target DPD error signal at the current time, and a sampled OFDM signal after analog-to-digital conversion to obtain a modified initial parameter set; and executing the method. The method for compensating for nonlinear distortion of a signal according to claim 5.

8. before iteratively modifying the initial parameter set based on the target DPD error signal and a preset low-noise variable step size least mean squares algorithm; If the absolute value of the target DPD error signal is equal to or greater than the threshold value of the DPD error signal, the initial parameter set is used as the model parameter set of the BL-DPD module. The method for compensating for nonlinear distortion of a signal according to claim 5.

9. When the combination of parameters of the model parameter set consists of the kernel coefficient, the nonlinearity order, the memory depth, and the order of the low-order LPF of the BL-CFR module, the model parameter set is inputting a sample OFDM signal in offline mode into the BL-DPD module and a preset CFR module in sequence to obtain a sample OFDM signal after DPD-CFR processing; obtaining a CFR-processed sample OFDM signal based on the sample OFDM signal in the offline mode and a conjugate parameter set corresponding to an initial parameter set of the BL-CFR module; obtaining a target CFR error signal based on the DPD-CFR processed sample OFDM signal and the CFR processed sample OFDM signal; performing iterative modifications to the initial parameter set based on the target CFR error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target CFR error signal is less than a set CFR error signal threshold; and setting the initial parameter set after iterative modification as the model parameter set of the BL-CFR module. The method for compensating for nonlinear distortion of a signal according to claim 4.

10. before making iterative modifications to the initial parameter set based on the target CFR error signal and a preset low noise variable step size least mean squares algorithm; The method further includes, when the absolute value of the target CFR error signal is equal to or greater than the threshold value of the CFR error signal, directly using the initial parameter set as the model parameter set of the BL-CFR module. The method for compensating for nonlinear distortion of a signal according to claim 9.

11. When the parameter combination of the model parameter set consists of the kernel coefficient, the nonlinearity order and the memory depth of the error compensation module, the model parameter set can be inputting a sample OFDM signal in offline mode into the nonlinear compensation fusion model and a preset high-order LPF, respectively, to obtain a sample OFDM signal after nonlinear distortion compensation and a sample OFDM signal after filtering; obtaining a target compensation error signal based on the nonlinear distortion compensated sample OFDM signal and the filtered sample OFDM signal; performing iterative adjustments to the initial parameter set of the error compensation module based on the target compensation error signal and a preset low-noise variable step size-least mean square algorithm until the absolute value of the target compensation error signal is less than a set compensation error signal threshold; and setting the initial parameter set after iterative modification as the model parameter set of the error compensation module. The method for compensating for nonlinear distortion of a signal according to claim 4.

12. before iteratively modifying an initial parameter set of the error compensation module based on the target compensation error signal and a preset low noise variable step size-least mean square algorithm; If the absolute value of the target compensation error signal is equal to or greater than the threshold value of the compensation error signal, the initial parameter set is used as the model parameter set of the error compensation module. The method for compensating for nonlinear distortion of a signal according to claim 11.

13. After obtaining an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal, obtaining an inverse DPD processed initial OFDM signal based on the nonlinear distortion compensated initial OFDM signal and a conjugate parameter set corresponding to a model parameter set of the BL-DPD module; obtaining a target distortion compensation error signal based on the initial OFDM signal after the nonlinear distortion compensation and the initial OFDM signal after the inverse DPD processing; and iteratively modifying the model parameter set based on the target distortion compensation error signal and a preset sine and error variable step size-least mean square algorithm until the absolute value of the target distortion compensation error signal becomes smaller than a preset distortion compensation error threshold. The method for compensating for nonlinear distortion of a signal according to any one of claims 1 to 12.

14. Obtaining an initial OFDM signal after inverse DPD processing based on the nonlinear distortion-compensated initial OFDM signal and a conjugate parameter set corresponding to a model parameter set of the BL-DPD module, performing digital-to-analog conversion, up-converting, and power amplification processing on the nonlinearly-compensated initial OFDM signal in this order to obtain a power-amplified initial OFDM signal; performing power attenuation, down-conversion, and analog-to-digital conversion processing on the power-amplified initial OFDM signal in this order to obtain an analog-to-digital converted initial OFDM signal; and obtaining the inverse DPD processed initial OFDM signal based on the analog-to-digital converted initial OFDM signal and a conjugate parameter set corresponding to the model parameter set. The method for compensating for nonlinear distortion of a signal according to claim 13.

15. performing iterative modifications to the model parameter set based on the target distortion compensation error signal and a preset sine and error variable step size-least mean square algorithm; Each time the model parameter set is modified, Obtaining sample OFDM signals after nonlinear distortion compensation corresponding to each of a plurality of historical time points adjacent to the current initial OFDM signal after nonlinear distortion compensation; obtaining an average value of the distortion compensation error signals at the current time of the initial OFDM signal after nonlinear distortion compensation based on historical distortion compensation error signals corresponding to the plurality of sample OFDM signals after nonlinear distortion compensation; obtaining a second target step size factor based on an error term corresponding to an average value of the distortion compensation error signal, a target distortion compensation error signal at the current time, and a history distortion compensation error signal at a history time immediately preceding the current time; modifying a model parameter set at the current time based on the second target step size factor, a conjugate distortion compensation error signal corresponding to the target distortion compensation error signal at the current time, and an initial OFDM signal after analog-to-digital conversion, to obtain a modified model parameter set; and executing the method. The method for compensating for nonlinear distortion of a signal according to claim 13.

16. The method for compensating for nonlinear distortion of a signal comprises: The method further includes iteratively modifying a model parameter set of the BL-DPD module based on a set period time. The method for compensating for nonlinear distortion of a signal according to claim 13.

17. A nonlinear compensation fusion model, The system includes a BL-DPD module, a BL-CFR module, and an error compensation module; the BL-DPD module, the BL-CFR module, and the error compensation module are connected in parallel, and the error compensation module is used to perform error compensation on the OFDM signals output from the BL-DPD module and the BL-CFR module. Nonlinear compensation fusion model.

18. The BL-DPD module and the BL-CFR module each use the same basis function. The nonlinear compensation fusion model of claim 17.

19. The nonlinear compensation fusion model is Obtaining, based on an initial OFDM signal, a first OFDM signal processed by the BL-DPD module, a second OFDM signal processed by the BL-CFR module, and a third OFDM signal processed by the error compensation module; is used to acquire an initial OFDM signal after nonlinear distortion compensation based on the first OFDM signal, the second OFDM signal, and the third OFDM signal. The nonlinear compensation fusion model of claim 17.

20. The nonlinear compensation fusion model further comprises: In an offline mode, the method is used to extract model parameter sets for the BL-DPD module, the BL-CFR module and the error compensation module based on a preset low-noise variable step size-least mean square algorithm. The nonlinear compensation fusion model of claim 17.

21. The nonlinear compensation fusion model further includes: In an online mode, the method is used to refresh a model parameter set for the nonlinear compensation fusion model based on a preset sine and error variable step size-least mean square algorithm and a set period time. The nonlinear compensation fusion model of claim 17.

22. The nonlinear compensation fusion model is In an online mode, the preset sine and error variable step size-least mean square algorithm and the set period time are used to refresh a model parameter set only for a BL-DPD module in the nonlinear compensation fusion model. The nonlinear compensation fusion model of claim 21.

23. 1. An OFDM communication system, comprising: A nonlinear compensation fusion model according to any one of claims 17 to 22, a first branch, a second branch, a third branch, and a fourth branch, the BL-DPD module and the first branch in the nonlinear compensation fusion model are used to iteratively modify an initial parameter set of the BL-DPD module in an offline mode to obtain a model parameter set of the BL-DPD module; The BL-CFR module and the second branch in the nonlinear compensation fusion model are used to iteratively modify the initial parameter set of the BL-CFR module in an offline mode to obtain a model parameter set of the BL-CFR module; The nonlinear compensation fusion model and the third branch are used to perform iterative modification on the initial parameter set of the error compensation module in an offline mode to obtain a model parameter set of the error compensation module; The nonlinear compensation fusion model and the fourth branch are used to perform iterative modification to the model parameter set of the BL-DPD module in an online mode. OFDM communication system.

24. the first branch comprises a digital-to-analog converter DAC, an up-converter, a power amplifier PA, an attenuator, a band-pass filter BPF, a down-converter, an analog-to-digital converter ADC, a training network POST-BL-DPD module, and a preset low-noise variable step size-least mean square algorithm module, which are arranged in sequence; 24. The OFDM communication system of claim 23.

25. The second branch comprises a CFR module, a training network POST-BL-DPD module, and a preset low-noise variable step size-least mean square algorithm module, which are arranged in sequence.

24. The OFDM communication system of claim 23.

26. The third branch comprises a low-pass filter LPF and a preset low-noise variable step size-least mean square algorithm module, which are arranged in sequence.

24. The OFDM communication system of claim 23.

27. the fourth branch comprises, in sequence, the DAC, the up-converter, the PA, the attenuator, the BPF, the down-converter, the ADC, the training network POST-BL-DPD module, and a preset sine and error variable step size-least mean square algorithm module; 25. The OFDM communication system of claim 24.

28. An electronic device including a memory, a processor, and a computer program stored in the memory and executable by the processor, the electronic device implementing the method according to any one of claims 1 to 16 when the processor executes the computer program. electronic equipment.

29. A computer-readable storage medium having stored thereon a computer program, the computer program being adapted to implement the steps of the method according to any one of claims 1 to 16 when executed by a processor. A computer-readable storage medium.

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