Frequency hopping predistortion method and system based on model prediction
By using a model-based prediction-based frequency hopping predistortion method, the problem of poor performance of digital predistortion technology in frequency hopping devices is solved, achieving efficient correction and lightweight design, and improving the transmission performance of frequency hopping signals.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA ELECTRONICS TECH GRP NO 7 RES INST
- Filing Date
- 2026-01-28
- Publication Date
- 2026-05-01
AI Technical Summary
Existing digital predistortion technology performs poorly in frequency hopping equipment, making it difficult to achieve effective correction within the very short transmission cycle of each hop, resulting in signal distortion and increased energy consumption, as well as increased equipment weight and size.
A model-based frequency hopping predistortion method is adopted. By simultaneously correcting modulator distortion and amplifier distortion, a digital predistortion coefficient prediction model is constructed. The preset coefficients are used for signal correction, reducing convergence time and achieving efficient correction of the signal per hop.
It improves the transmission performance of frequency hopping signals, reduces the waiting time and energy consumption of equipment, and promotes the lightweight design of frequency hopping equipment.
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Figure CN121966608A_ABST
Abstract
Description
Model-based prediction-based frequency hopping predistortion method and system Technical Field
[0001] This invention relates to the technical field of frequency hopping communication, and more specifically, to a model-predictive frequency hopping predistortion method and system. Background Technology
[0002] Frequency hopping transmission is a communication method that rapidly changes its operating frequency during signal transmission and reception. It helps to evade targeted electromagnetic interference released by the enemy and has important value in information warfare.
[0003] Frequency-hopping communication equipment used for frequency-hopping transmission requires several watts of output power to ensure long-distance communication needs. While outputting high power, it also requires sufficiently low signal distortion. Therefore, to avoid the power amplifier operating at full power with high distortion, power reduction measures, such as power back-off, are generally required to keep the frequency-hopping communication equipment operating in a linear region with lower distortion. However, this significantly reduces energy conversion efficiency and necessitates the use of heavy heat dissipation devices, increasing the weight and size of the equipment.
[0004] Digital predistortion (DPD) technology can solve the dilemma of the trade-off between low distortion and high efficiency. However, DPD performs poorly in frequency-hopping devices, making it difficult to apply. This is because digital predistortion typically requires convergence times on the order of milliseconds or even seconds, while the continuous dwell time of frequency-hopping devices at each operating frequency may be less than one millisecond. Their circuit characteristics are constantly changing rapidly, causing the corresponding algorithm to fail to converge to the optimal state.
[0005] To address frequency-hopping transmission distortion in frequency-hopping devices, existing technologies perform independent calculations and corrections on each hop signal, and minimize adjustment time by optimizing basis functions and tracking algorithms; alternatively, they treat frequency-hopping transmission as a large-bandwidth fixed-frequency system covering the entire frequency hopping range, and then use a fixed-frequency method for correction. Even if the former ultimately achieves sufficient correction, the overall performance is low due to previous poor performance; the latter is costly and energy-intensive, contradicting the initial goal of energy conservation.
[0006] Furthermore, the radio frequency (RF) distortion generated by the transmitter in frequency-hopping equipment mainly includes modulator distortion and amplifier nonlinear distortion. Correcting RF distortion typically involves first correcting modulation distortion and then nonlinear distortion to avoid the distortion components from the preceding stages generating more complex and difficult-to-process distortion components in the subsequent stages. While this method is simple and easy to implement, it lengthens the processing flow, is unsuitable for the very short transmission cycles of frequency-hopping systems, and results in low overall performance. Summary of the Invention
[0007] To address the issue of poor performance of existing digital predistortion technology in frequency hopping devices, this invention proposes a model-predictive-based frequency hopping predistortion method and system. This method improves the performance of digital predistortion technology in frequency hopping devices, enhances the transmission performance of frequency hopping signals, and facilitates the lightweighting of frequency hopping devices.
[0008] To achieve the above-mentioned technical effects, the technical solution of the present invention is as follows:
[0009] Firstly, this application proposes a model-based prediction-based frequency hopping predistortion method, comprising the following steps: S1: Based on the preset coefficient vector of the current hop and the unified representation of the distortion compensation signal, compensate for the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop to generate a pre-compensation signal; S2: Use the pre-compensation signal to correct the initial frequency hopping input signal to obtain a digital predistortion signal; S3: Based on the digital predistortion signal, obtain a frequency hopping output signal, process the frequency hopping output signal to generate an error signal; S4: Based on the unified representation of the initial frequency hopping input signal, the error signal, and the distortion compensation signal, calculate... S5: Solve the predistortion optimization coefficient vector of the current hop. Based on the predistortion optimization coefficient vector of the current hop and the preset coefficients, obtain the total predistortion optimization coefficient vector; S6: Describe each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating band. Based on the description results, obtain the frequency response equation set; S7: Solve the frequency response equation set to obtain the digital predistortion coefficient prediction model for any frequency within the operating band; S8: Use the digital predistortion coefficient prediction model and the next hop operating frequency to solve for the preset coefficients of the frequency hopping signal of the next hop; S9: Determine whether the frequency hopping signal has been transmitted. If yes, end; otherwise, return to S1.
[0010] Preferably, the expression for the uniform representation of the distortion compensation signal is:
[0011] in, This indicates modulator distortion, and k represents time. Indicates conjugate operation; Indicates the leaked components in the image. This indicates the DC offset corresponding to the leaked local oscillator signal; This is the representation of the amplifier distortion model.
[0012] Preferably, based on the preset coefficient vector of the current jump, the process of generating the pre-compensation signal is as follows: taking the baseband equivalent form of the amplifier distortion model part, the expression is:
[0013] in, This represents the specific amplifier distortion model; M represents the memory depth of the RF hardware, and P represents the order of the nonlinear model. Let the coefficients of the corresponding terms be ; let the preset coefficient vector of the current jump be . , Both represent coefficient vectors, denoted as predistortion optimization coefficients C, and their expression is:
[0014] Where N represents the number of elements; let Take the initial frequency hopping input signal of the current hop. Let the predistortion optimization coefficient C be the preset coefficient vector of the current jump. Calculations yielded ,Will As a pre-compensation signal .
[0015] Preferably, the frequency hopping input signal is corrected using the pre-compensation signal to obtain a digital predistortion signal. The process is as follows: the pre-compensation signal is added to the initial frequency hopping input signal to obtain the digital predistortion signal, expressed as:
[0016] in, Indicates digital predistortion signal, This represents the initial frequency hopping input signal. This indicates a pre-compensation signal.
[0017] Preferably, a frequency-hopping output signal is obtained based on the digital predistortion signal. The frequency-hopping output signal is then processed to generate an error signal. The process involves: sequentially performing digital-to-analog conversion, modulating, and amplifying the digital predistortion signal to obtain the frequency-hopping output signal; converting the frequency-hopping output signal to an intermediate frequency and filtering it before converting it into a digital signal; performing frequency and phase correction on the digital signal, and aligning its amplitude and time delay to generate a feedback signal. ; the initial frequency hopping input signal With the feedback signal Subtracting them yields the error signal. The expression is: .
[0018] Preferably, based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal for the current hop, the predistortion optimization coefficient vector for the current hop is solved. Based on the predistortion optimization coefficient vector of the current hop and the preset coefficients, the total predistortion optimization coefficient vector is obtained. The process is as follows: Based on the unified representation of the distortion compensation signal, the predistortion optimization coefficient vector C is solved, denoted as... Based on the predistortion optimization coefficient vector of the current jump and the preset coefficient vector of the current jump. The total coefficient vector of predistortion optimization is obtained. The expression is:
[0019] in, This represents the operating frequency of the nth hop, and N represents the number of elements.
[0020] Preferably, each element in the predistortion optimization total coefficient vector is described based on the frequency within the frequency hopping operating band. Based on the description results, a set of frequency response equations is obtained. The process is as follows: using Q basis functions... Describe the total coefficient vector of predistortion optimization any element in With frequency The changing pattern was used to obtain the frequency of the most recent L-jump. With any element The frequency response equations:
[0021] in, is a coefficient.
[0022] Preferably, the coefficients of the frequency response equations are solved. The expression for the digital predistortion coefficient prediction model is as follows: .
[0023] Preferably, the preset coefficients of the next-hop frequency hopping signal are solved using a digital predistortion coefficient prediction model and the next-hop operating frequency. The process is as follows: the next-hop operating frequency is... Input the digital predistortion coefficient prediction model and solve for the preset coefficients of the next hop. The expression is: .
[0024] Secondly, this application proposes a model-predictive frequency hopping predistortion system to implement the aforementioned model-predictive frequency hopping predistortion method, comprising: a pre-compensation signal generation module, used to compensate for the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop based on a preset coefficient vector and a unified representation of the distortion compensation signal, to generate a pre-compensation signal; a pre-distortion signal generation module, used to correct the initial frequency hopping input signal using the pre-compensation signal to obtain a digital pre-distortion signal; an error signal generation module, used to obtain a frequency hopping output signal based on the digital pre-distortion signal, and to process the frequency hopping output signal to generate an error signal; and a pre-distortion optimization coefficient vector acquisition module, used to obtain the initial frequency hopping input signal of the current hop, the error signal, and the distortion compensation signal. The system employs a unified signal representation, solves for the predistortion optimization coefficient vector of the current hop, and obtains the total predistortion optimization coefficient vector based on the current hop's predistortion optimization coefficient vector and preset coefficients. A frequency response equation construction module describes each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating band, and obtains a set of frequency response equations based on the description results. A coefficient prediction model construction module solves the frequency response equations to obtain a digital predistortion coefficient prediction model for any frequency within the operating band. A preset coefficient solving module uses the digital predistortion coefficient prediction model and the next hop operating frequency to solve for the preset coefficients of the frequency hopping signal in the next hop. A loop module determines whether the frequency hopping signal transmission is complete; if so, the process ends; otherwise, it returns to the pre-compensation signal generation module.
[0025] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention proposes a model-predictive frequency hopping predistortion method and system, which reduces the waiting time for the preceding stage to converge by simultaneously correcting modulator distortion and amplifier distortion; by constructing a digital predistortion coefficient prediction model, the preset coefficients of the next hop frequency hopping signal can be accurately solved; before each hop frequency hopping input signal is input to the frequency hopping device, the preset coefficients are used for correction to obtain a digital predistorted signal, avoiding the problem of poor early-stage signal performance leading to low overall performance. This invention can improve the performance of digital predistortion technology in frequency hopping devices, enhance the transmission performance of frequency hopping signals, and facilitate the lightweighting of frequency hopping devices. Attached Figure Description
[0026] Figure 1 shows a schematic flowchart of the model prediction-based frequency hopping predistortion method proposed in this embodiment of the invention; Figure 2 shows a flowchart of the model prediction-based frequency hopping predistortion method proposed in this embodiment of the invention; Figure 3 shows the global basis function graph proposed in this embodiment of the invention; Figure 4 shows the piecewise basis function graph proposed in this embodiment of the invention; Figure 5 shows the system composition diagram of the model prediction-based frequency hopping predistortion proposed in this embodiment of the invention. Detailed Implementation
[0027] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent actual dimensions. It is understandable to those skilled in the art that some well-known content may be omitted in the drawings.
[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments; the positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting the present patent.
[0029] Example 1 provides a model-based prediction-based frequency hopping predistortion method. The flowchart of this method is shown in Figure 1, and includes the following steps: S1: Based on the preset coefficient vector of the current hop and the unified representation of the distortion compensation signal, compensate for the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop to generate a pre-compensation signal; S2: Use the pre-compensation signal to correct the initial frequency hopping input signal to obtain a digital predistortion signal; S3: Based on the digital predistortion signal, obtain the frequency hopping output signal; process the frequency hopping output signal to generate an error signal; S4: Based on the initial frequency hopping input signal of the current hop, the error signal, and the distortion compensation signal... S5: Solve the predistortion optimization coefficient vector for the current hop, and obtain the total predistortion optimization coefficient vector based on the current hop's predistortion optimization coefficient vector and preset coefficients; S6: Describe each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating band, and obtain the frequency response equation set based on the description results; S7: Solve the frequency response equation set to obtain the digital predistortion coefficient prediction model for any frequency within the operating band; S8: Use the digital predistortion coefficient prediction model and the next hop operating frequency to solve for the preset coefficients of the frequency hopping signal for the next hop; S9: Determine whether the frequency hopping signal has been transmitted completely. If yes, end; otherwise, return to S1.
[0030] In this embodiment, based on the unified representation of the preset coefficient vector and distortion compensation signal of the current hop, the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop are compensated to generate a pre-compensation signal. The initial frequency hopping input signal is then corrected using the pre-compensation signal to obtain a digital pre-distortion signal. The digital pre-distortion signal is transmitted using the transmitter of the frequency hopping device to obtain a frequency hopping output signal. The frequency hopping output signal is processed through a feedback channel to generate an error signal, which is the residual signal distortion after correction. Based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal of the current hop, the pre-distortion optimization coefficient vector of the current hop is solved. Based on the pre-distortion optimization coefficient vector of the current hop and the preset coefficients, the total pre-distortion optimization coefficient vector is obtained. Each element in the total pre-distortion optimization coefficient vector is described based on the frequency within the frequency hopping operating frequency band. Based on the description results, a set of frequency response equations is obtained. The set of frequency response equations is solved to obtain a digital pre-distortion coefficient prediction model for any frequency within the operating frequency band. By using a digital predistortion coefficient prediction model and the next-hop operating frequency, the preset coefficients of the frequency hopping signal for the next hop are solved.
[0031] Example 2 In this example, the flowchart of the frequency hopping predistortion method based on model prediction is shown in Figure 2, including a digital predistortion signal generation module 1, a frequency hopping device transmitter 2, a frequency hopping output signal preprocessing module 3, a digital predistortion coefficient prediction model solving module 4, and a digital predistortion coefficient prediction model construction and preset coefficient prediction module 5.
[0032] The unified expression for the distortion compensation signal is as follows:
[0033] in, This indicates modulator distortion, and k represents time. Indicates conjugate operation; Indicates the leaked components in the image. This indicates the DC offset corresponding to the leaked local oscillator signal; This is the representation of the amplifier distortion model.
[0034] Specifically, regarding signals In scenarios with large bandwidth and uneven in-band characteristics of the modulator, the distortion compensation signal is uniformly represented by the following expression:
[0035] As shown in Figure 2, in the digital predistortion signal generation module 1, a pre-compensation signal is generated using preset coefficients. , will pre-compensated signal With the initial frequency hopping input signal Add them together to obtain the digital predistortion signal. In the initial stage of frequency hopping signal transmission, the preset coefficient is the coefficient measured at the frequency point using a fixed-frequency method. After the digital predistortion coefficient prediction model stabilizes, the preset coefficients are the coefficients predicted using the digital predistortion coefficient prediction model. The process of generating the pre-compensated signal is as follows: The baseband equivalent form of the amplifier distortion model is taken, and the expression is:
[0036] in, This represents the specific amplifier distortion model; M represents the memory depth of the RF hardware, and P represents the order of the nonlinear model. Let the coefficients of the corresponding terms be ; let the preset coefficient vector of the current jump be . , Both represent coefficient vectors, denoted as predistortion optimization coefficients C, and their expression is:
[0037] Where N represents the number of elements; let Take the initial frequency hopping input signal of the current hop. Let the predistortion optimization coefficient C be the preset coefficient vector of the current jump. Calculations yielded ,Will As a pre-compensation signal .
[0038] Specifically, in the digital predistortion signal model, the amplifier distortion model part is taken in baseband equivalent form. The amplifier distortion model part is the distortion or error part of the amplifier output signal. In practical applications, Chebyshev polynomials, simplified Volterra polynomials, etc. can be used as amplifier distortion models.
[0039] Preferably, the frequency hopping input signal is corrected using the pre-compensation signal to obtain a digital predistortion signal. The process is as follows: the pre-compensation signal is added to the initial frequency hopping input signal to obtain the digital predistortion signal, expressed as:
[0040] in, Indicates digital predistortion signal, This represents the initial frequency hopping input signal. This indicates a pre-compensation signal.
[0041] Based on the digital predistortion signal, a frequency-hopping output signal is obtained. This frequency-hopping output signal is then processed to generate an error signal. The process involves sequentially performing digital-to-analog conversion, modulation, and amplification on the digital predistortion signal to obtain the frequency-hopping output signal. This signal is then frequency-converted to an intermediate frequency (IF), filtered, and converted back to a digital signal. The digital signal undergoes frequency and phase correction, as well as amplitude and time delay alignment, to generate a feedback signal. ; the initial frequency hopping input signal With the feedback signal Subtracting them yields the error signal. The expression is: .
[0042] Specifically, as shown in Figure 2, a digital predistortion signal is generated using a frequency-hopping transmitter 2. The frequency-hopping transmitter 2 includes a digital-to-analog converter (DAC), a modulator, and an amplifier. The DAC converts the digital predistortion signal into an analog signal, and the modulator and amplifier perform quadrature modulation and amplification on the analog signal to obtain a frequency-hopping output signal. The frequency-hopping output signal preprocessing module 3 processes the signal to obtain an error signal.
[0043] As shown in Figure 2, based on the initial frequency hopping input signal Sum of error signals The predistortion coefficient prediction model is solved using module 4 to obtain the predistortion optimization total coefficient vector. Based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal for the current hop, the predistortion optimization coefficient vector for the current hop is solved. Based on the predistortion optimization coefficient vector and preset coefficients for the current hop, the total predistortion optimization coefficient vector is obtained. The process is as follows: Based on the unified representation of the distortion compensation signal, the predistortion optimization coefficient vector C is solved, denoted as... Based on the predistortion optimization coefficient vector of the current jump and the preset coefficient vector of the current jump. The total coefficient vector of predistortion optimization is obtained. The expression is:
[0044] in, This represents the operating frequency of the nth hop, and N represents the number of elements.
[0045] Specifically, based on the unified representation of distortion-compensated signals, let Take error signal , Take the initial frequency hopping input signal The predistortion optimization coefficient C is obtained by solving the problem, and is denoted as... .
[0046] As shown in Figure 2, the total coefficient vector is optimized based on predistortion. The digital predistortion coefficient prediction model is constructed using the digital predistortion coefficient prediction model and the preset coefficient prediction module 5. This model is then used to predict the digital predistortion coefficients using the next hop operating frequency. Solve for the preset coefficients of the next hop Each element in the predistortion optimization total coefficient vector is described based on the frequency within the frequency hopping operating band. Based on the description results, a set of frequency response equations is obtained. The process is as follows: using Q basis functions... Describe the total coefficient vector of predistortion optimization any element in With frequency The changing pattern was used to obtain the frequency of the most recent L-jump. With any element The frequency response equations:
[0047] in, is a coefficient.
[0048] Specifically, the basis function is a global function covering the entire operating frequency band or a piecewise function covering a portion of the operating frequency band. The global function can take the form of a Chebyshev curve, as shown in Figure 3. The piecewise function can take the form of a B-spline curve, as shown in Figure 4; in Figures 3 and 4, the vertical axis represents amplitude, and the horizontal axis represents the operating frequency of the frequency hopping device.
[0049] Preferably, the coefficients of the frequency response equations are solved, and the expression for the digital predistortion coefficient prediction model is: .
[0050] Specifically, the coefficients of the frequency response equations are solved based on the least squares criterion. A digital predistortion coefficient prediction model was obtained.
[0051] Preferably, the preset coefficients of the next-hop frequency hopping signal are solved using a digital predistortion coefficient prediction model and the next-hop operating frequency. The process is as follows: the next-hop operating frequency is... Input the digital predistortion coefficient prediction model and solve for the preset coefficients of the next hop. The expression is: .
[0052] Example 3 This example provides a model-predictive frequency hopping predistortion system, as shown in Figure 5. This system is used to implement the model-predictive frequency hopping predistortion method, including: a pre-compensation signal generation module, used to compensate for the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop based on the preset coefficient vector and the distortion compensation signal of the current hop, generating a pre-compensation signal; a pre-distortion signal generation module, used to correct the initial frequency hopping input signal using the pre-compensation signal to obtain a digital predistortion signal; an error signal generation module, used to obtain a frequency hopping output signal based on the digital predistortion signal, and process the frequency hopping output signal to generate an error signal; and a predistortion optimization coefficient vector acquisition module, used to obtain the pre-distortion optimization coefficient vector based on the initial frequency hopping input signal of the current hop, the error signal, and the... The distortion compensation signal is uniformly represented, and the predistortion optimization coefficient vector of the current hop is solved. Based on the predistortion optimization coefficient vector of the current hop and the preset coefficients, the total predistortion optimization coefficient vector is obtained. The frequency response equation system construction module is used to describe each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating frequency band. Based on the description results, the frequency response equation system is obtained. The coefficient prediction model construction module is used to solve the frequency response equation system to obtain a digital predistortion coefficient prediction model for any frequency within the operating frequency band. The preset coefficient solving module is used to solve the preset coefficients of the frequency hopping signal of the next hop using the digital predistortion coefficient prediction model and the next hop operating frequency. The loop module is used to determine whether the frequency hopping signal has been transmitted. If so, the process ends; otherwise, it returns to the pre-compensation signal generation module.
[0053] The same or similar reference numerals correspond to the same or similar components; the terms describing positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention; obviously, the above embodiments of the invention are merely examples for clearly illustrating the invention, and are not intended to limit the implementation of the invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the invention should be included within the scope of protection of the claims of the invention.
Claims
1. A frequency hopping predistortion method based on model prediction, characterized in that, Includes the following steps: S1: Based on the preset coefficient vector and the unified representation of the distortion compensation signal of the current hop, the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop are compensated to generate a pre-compensation signal; S2: The initial frequency hopping input signal is corrected using the pre-compensation signal to obtain a digital pre-distortion signal; S3: Based on the digital predistortion signal, obtain the frequency hopping output signal, process the frequency hopping output signal, and generate an error signal; S4: Based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal for the current hop, solve for the predistortion optimization coefficient vector for the current hop. Based on the predistortion optimization coefficient vector for the current hop and the preset coefficients, obtain the total predistortion optimization coefficient vector. S5: Describe each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating band. Based on the description results, obtain the frequency response equation set. S6: Solve the frequency response equation set to obtain a digital predistortion coefficient prediction model for any frequency within the operating band. S7: Using the digital predistortion coefficient prediction model and the next hop operating frequency, solve for the preset coefficients of the frequency hopping signal of the next hop; S8: Determine whether the frequency hopping signal has been transmitted. If yes, end; otherwise, return to S1.
2. The frequency hopping predistortion method based on model prediction according to claim 1, characterized in that, The unified expression for the distortion compensation signal is as follows: in, This indicates modulator distortion, and k represents time. Indicates conjugate operation; Indicates the leaked components in the image. This indicates the DC offset corresponding to the leaked local oscillator signal; This is the representation of the amplifier distortion model.
3. The frequency hopping predistortion method based on model prediction according to claim 2, characterized in that, Based on the preset coefficient vector of the current jump, the process of generating the pre-compensation signal is as follows: taking the baseband equivalent form of the amplifier distortion model part, the expression is: in, This represents the specific amplifier distortion model; M represents the memory depth of the RF hardware, and P represents the order of the nonlinear model. Let the coefficients of the corresponding terms be ; let the preset coefficient vector of the current jump be . ， Both represent coefficient vectors, denoted as predistortion optimization coefficients C, and their expression is: Where N represents the number of elements; let Take the initial frequency hopping input signal of the current hop. Let the predistortion optimization coefficient C be the preset coefficient vector of the current jump. Solving for the given information yields the following results. The solution obtained As a pre-compensation signal 。 4. The frequency hopping predistortion method based on model prediction according to claim 1, characterized in that, The frequency-hopping input signal is corrected using the pre-compensation signal to obtain a digital predistortion signal. The process is as follows: the pre-compensation signal is added to the initial frequency-hopping input signal to obtain the digital predistortion signal, expressed as: in, Indicates digital predistortion signal, This represents the initial frequency hopping input signal. This indicates a pre-compensation signal.
5. The frequency hopping predistortion method based on model prediction according to claim 1, characterized in that, Based on the digital predistortion signal, a frequency-hopping output signal is obtained. This frequency-hopping output signal is then processed to generate an error signal. The process involves sequentially performing digital-to-analog conversion, modulation, and amplification on the digital predistortion signal to obtain the frequency-hopping output signal. This signal is then frequency-converted to an intermediate frequency (IF), filtered, and converted back to a digital signal. The digital signal undergoes frequency and phase correction, as well as amplitude and time delay alignment, to generate a feedback signal. ; the initial frequency hopping input signal With the feedback signal Subtracting them yields the error signal. The expression is: 。 6. The frequency hopping predistortion method based on model prediction according to claim 5, characterized in that, Based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal for the current hop, the predistortion optimization coefficient vector for the current hop is solved. Based on the predistortion optimization coefficient vector and preset coefficients for the current hop, the total predistortion optimization coefficient vector is obtained. The process is as follows: Based on the unified representation of the distortion compensation signal, the predistortion optimization coefficient vector C is solved, denoted as... Based on the predistortion optimization coefficient vector of the current jump and the preset coefficient vector of the current jump. The total coefficient vector of predistortion optimization is obtained. The expression is: in, This represents the operating frequency of the nth hop, and N represents the number of elements.
7. The frequency hopping predistortion method based on model prediction according to claim 6, characterized in that, Each element in the predistortion optimization total coefficient vector is described based on the frequency within the frequency hopping operating band. Based on the description results, a set of frequency response equations is obtained. The process is as follows: using Q basis functions... Describe the total coefficient vector of predistortion optimization any element in With frequency The changing pattern was used to obtain the frequency of the most recent L-jump. With any element The frequency response equations: in, is a coefficient.
8. The frequency hopping predistortion method based on model prediction according to claim 7, characterized in that, Solving the frequency response equations, the expression for the digital predistortion coefficient prediction model is as follows: 。 9. The frequency hopping predistortion method based on model prediction according to claim 1, characterized in that, Using a digital predistortion coefficient prediction model and the next-hop operating frequency, the preset coefficients of the next-hop frequency-hopping signal are solved. The process is as follows: The next-hop operating frequency... Input the digital predistortion coefficient prediction model and solve for the preset coefficients of the next hop. The expression is: 。 10. A model-predictive-based frequency hopping predistortion system, used to implement the model-predictive-based frequency hopping predistortion method according to any one of claims 1-9, characterized in that, include: The pre-compensation signal generation module is used to compensate for the modulator distortion and amplifier distortion of the initial frequency hopping input signal of the current hop based on the preset coefficient vector and the unified representation of the distortion compensation signal of the current hop, and generate a pre-compensation signal. The predistortion signal generation module is used to correct the initial frequency hopping input signal using the pre-compensation signal to obtain a digital predistortion signal; An error signal generation module is used to obtain a frequency hopping output signal based on a digital predistortion signal, process the frequency hopping output signal, and generate an error signal. The predistortion optimization coefficient vector acquisition module is used to solve the predistortion optimization coefficient vector of the current hop based on the unified representation of the initial frequency hopping input signal, error signal, and distortion compensation signal of the current hop. Based on the predistortion optimization coefficient vector of the current hop and the preset coefficients, the total predistortion optimization coefficient vector is obtained. The frequency response equation system construction module is used to describe each element in the total predistortion optimization coefficient vector based on the frequency within the frequency hopping operating frequency band. Based on the description results, the frequency response equation system is obtained. The coefficient prediction model construction module is used to solve the frequency response equation set to obtain a digital predistortion coefficient prediction model for any frequency within the working frequency band. The preset coefficient solution module is used to solve the preset coefficients of the frequency hopping signal of the next hop using the digital predistortion coefficient prediction model and the next hop operating frequency; the loop module is used to determine whether the frequency hopping signal has been transmitted. If so, it ends; otherwise, it returns to the pre-compensation signal generation module.