A frequency pre-distortion apparatus, a frequency pre-distortion method and a transmitting system

Abstract

The embodiment of the present application discloses a frequency pre-distortion device and a frequency pre-distortion method, which can acquire a main distortion signal located in a main frequency band and an auxiliary distortion signal located in an interference frequency band based on a first radio frequency signal, then, pre-distort a second baseband signal based on the main distortion signal and the auxiliary distortion signal respectively to obtain a first pre-distortion signal and a second pre-distortion signal, and synthesize the first pre-distortion signal and the second pre-distortion signal into a third pre-distortion signal. Since the signal component located in the interference frequency band in the third pre-distortion signal can be offset under the action of non-linear distortion after passing through a radio frequency amplifier, the radio frequency signal provided by the radio frequency amplifier to the antenna has no signal located in the interference frequency band, but only has a signal located in the main frequency band.

Description

Technical Field

[0001] This application relates to the field of communications, and more particularly to a frequency predistortion device, a frequency predistortion method, and a transmission system. Background Technology

[0002] A radio frequency power amplifier (RF PA) is an important component of a wireless transmitter. Its main function is to amplify the low-power radio frequency signal generated by the modulation oscillation circuit to a sufficient level of power so that the power of the radio frequency signal supplied to the antenna can reach the power of the antenna's radiation.

[0003] However, the RF amplifier (or the RF link containing the RF amplifier) ​​may produce nonlinear distortion, causing the RF signal supplied to the antenna to contain not only the frequency components of the useful signal, but also other frequency components, which in turn causes significant interference to wireless communication devices.

[0004] In traditional technology, predistortion devices are added to the radio frequency amplifier to mitigate nonlinear distortion. However, traditional predistortion devices only consider correcting the nonlinear distortion of the main frequency band of the radio frequency signal and do not provide a solution to eliminate frequency components in other frequency bands caused by nonlinear distortion. Summary of the Invention

[0005] This application provides a frequency predistortion device, a frequency predistortion method, and a transmission system for eliminating frequency components in radio frequency signals that are generated in other frequency bands due to nonlinear distortion.

[0006] In a first aspect, this application provides a frequency predistortion device applied in a transmission system, the frequency predistortion device comprising:

[0007] The frequency segmentation module is used to obtain an auxiliary distortion signal located in the interference frequency band based on a first radio frequency signal. The first radio frequency signal is a nonlinear distortion radio frequency signal obtained by up-conversion and radio frequency amplification of a first baseband signal. The first baseband signal is located in the main frequency band, and the first radio frequency signal is located in both the main frequency band and the interference frequency band. The signal component of the first radio frequency signal located in the interference frequency band is generated by the nonlinear distortion of the signal component of the first baseband signal located in the main frequency band.

[0008] The first predistortion module is used to generate a first predistortion signal based on the second baseband signal and the auxiliary distortion signal. The second baseband signal is located in the main frequency band, and the first predistortion signal is located in the interference frequency band. The first predistortion signal is used to cancel the signal component located in the interference frequency band generated by radio frequency amplification, so that the signal after radio frequency amplification does not contain the signal component located in the interference frequency band.

[0009] The first baseband signal can be understood as the baseband signal generated by the baseband signal generation module at a certain historical moment. The second baseband signal is the baseband signal generated by the baseband signal generation module at the current moment, and it is the baseband signal that needs to undergo pre-distortion processing.

[0010] In this embodiment, the frequency segmentation module can obtain the secondary distortion signal located in the interference frequency band from the first radio frequency signal, and perform predistortion processing based on the secondary distortion signal and the second baseband signal to obtain the first predistortion signal. Since the first predistortion signal can be canceled out by the nonlinear distortion after passing through the radio frequency amplifier, the radio frequency signal provided to the antenna by the radio frequency amplifier does not contain signals located in the interference frequency band. Therefore, it is beneficial to accurately eliminate signal components located in the interference frequency band in the radio frequency signal provided to the antenna.

[0011] In one possible implementation, the frequency segmentation module is further configured to acquire the main distortion signal located in the main frequency band based on the first radio frequency signal;

[0012] The frequency predistortion device also includes: a second predistortion module and a merging module;

[0013] The second predistortion module is used to generate a second predistortion signal based on the second baseband signal and the main distortion signal, wherein the second predistortion signal is located in the main frequency band;

[0014] The merging module is used to generate a third predistorted signal based on the first predistorted signal and the second predistorted signal. The third predistorted signal is located in the main frequency band and the interference frequency band. The second radio frequency signal obtained by radio frequency amplification of the third predistorted signal is located in the main frequency band.

[0015] The auxiliary distortion signal located in the interference frequency band is determined based on the signal component of the first radio frequency signal located in the interference frequency band, and the main distortion signal located in the main frequency band is determined based on the signal component of the first radio frequency signal located in the main frequency band.

[0016] In this embodiment, the frequency predistortion device can acquire a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band based on the first radio frequency signal. Then, it performs predistortion processing on the second baseband signal based on the aforementioned primary distortion signal and auxiliary distortion signal to obtain a first predistortion signal and a second predistortion signal, respectively. The first predistortion signal and the second predistortion signal are then combined into a third predistortion signal. Since the signal component in the interference frequency band of the third predistortion signal can be canceled out by the nonlinear distortion after passing through the radio frequency amplifier, the radio frequency signal provided to the antenna by the radio frequency amplifier does not contain signals in the interference frequency band, but only signals in the primary frequency band.

[0017] In one possible implementation, the frequency segmentation module includes at least one filter; a first filter in the at least one filter is used to filter out the analog signal component located in the main frequency band from the first analog signal to obtain the analog signal component located in the interference frequency band in the first analog signal; wherein the first analog signal is a signal obtained by down-converting the first radio frequency signal; or, the first analog signal is the first radio frequency signal.

[0018] In this embodiment, a first filter is proposed to be included in the frequency segmentation module. This first filter can filter out the analog signal components located in the main frequency band of the first analog signal during the analog signal stage, while retaining the analog signal components located in the interference frequency band of the first analog signal. Furthermore, it is proposed that the down-conversion operation can be performed first, followed by the filtering operation; or the filtering operation can be performed first, followed by the down-conversion operation.

[0019] In one possible implementation, the second filter in the at least one filter is used to filter out the analog signal component located in the interference frequency band from the second analog signal to obtain the analog signal component located in the main frequency band in the second analog signal; wherein the second analog signal is a signal obtained by down-converting the first radio frequency signal; or, the second analog signal is the first radio frequency signal.

[0020] In this embodiment, a second filter is proposed to be included in the frequency segmentation module. This second filter can filter out the analog signal components located in the interference frequency band of the second analog signal during the analog signal stage, while retaining the analog signal components located in the main frequency band of the second analog signal. Furthermore, it is proposed that the down-conversion operation can be performed first, followed by the filtering operation; or the filtering operation can be performed first, followed by the down-conversion operation.

[0021] In one possible implementation, the frequency segmentation module further includes: a first analog-to-digital conversion module for sampling the analog signal component in the first analog signal located in the interference frequency band to obtain the auxiliary distortion signal; and a second analog-to-digital conversion module for sampling the analog signal component in the second analog signal located in the main frequency band to obtain the main distortion signal.

[0022] In this embodiment, since the predistortion module (e.g., the first predistortion module and the second predistortion module) performs predistortion processing on the digital signal, the analog signal component located in the interference frequency band and the analog signal component located in the main frequency band need to be converted from analog to digital to obtain the auxiliary distortion signal and the main distortion signal.

[0023] In one possible implementation, the frequency segmentation module further includes: a first analog-to-digital conversion module for sampling the analog signal component in the first analog signal located in the interference frequency band to obtain the auxiliary distortion signal; and a second analog-to-digital conversion module for sampling the signal obtained by down-conversion of the first radio frequency signal to obtain the main distortion signal.

[0024] In one possible implementation, the frequency segmentation module further includes: a first variable gain amplifier for amplifying the analog signal component of the first analog signal input to the first analog-to-digital converter located in the interference frequency band; and a second variable gain amplifier for amplifying the analog signal component of the second analog signal input to the second analog-to-digital converter located in the main frequency band; wherein the amplification ratio of the second variable gain amplifier is different from that of the first variable gain amplifier.

[0025] Optionally, the amplification ratio of the second variable gain amplifier is less than that of the first variable gain amplifier.

[0026] In this embodiment, it is proposed to add variable gain amplifiers to the two branches to amplify the power of the signal entering the first analog-to-digital converter module, so as to ensure that the power of the signal entering the first analog-to-digital converter module and the signal entering the second analog-to-digital converter module are the same or similar.

[0027] In one possible implementation, the frequency segmentation module further includes: a first variable gain amplifier for amplifying the analog signal component of the first analog signal input to the first analog-to-digital converter located in the interference frequency band; and a second variable gain amplifier for amplifying the signal obtained by down-conversion of the first radio frequency signal input to the second analog-to-digital converter; wherein the amplification ratio of the second variable gain amplifier is different from that of the first variable gain amplifier.

[0028] In one possible implementation, the combining module includes a digital signal combiner; the digital signal combiner is used to combine the first predistorted signal and the second predistorted signal into a predistorted baseband signal, the frequency range of the predistorted baseband signal including the main frequency band and the interference frequency band, and the third predistorted signal is a signal obtained by digital-to-analog conversion and up-conversion of the predistorted baseband signal.

[0029] In this embodiment, performing the merging process at the digital signal stage helps ensure the accuracy of the merging operation and saves on digital-to-analog converters and mixers.

[0030] In one possible implementation, the combining module includes an analog signal combiner and a third filter; the third filter is used to filter out noise located in the interference frequency band from the third analog signal and output a noise-reduced third analog signal, the third analog signal being an analog signal obtained by digital-to-analog conversion based on the second predistorted signal; the analog signal combiner is used to generate a predistorted analog signal based on the noise-reduced third analog signal and a fourth analog signal, the fourth analog signal being an analog signal obtained by digital-to-analog conversion based on the first predistorted signal, and the third predistorted signal being a radio frequency signal obtained by up-conversion based on the predistorted analog signal.

[0031] In this embodiment, digital-to-analog conversion is performed first, followed by the merging process. Furthermore, a filter is used before the merging process to remove noise in the interference frequency band of the third analog signal, which helps reduce the noise of the intermediate frequency signal to be merged, thereby reducing the noise of the merged signal. Additionally, performing digital-to-analog conversion and merging before up-conversion—that is, performing the merging process at the intermediate frequency signal stage—reduces the complexity of the analog merging unit and lowers the requirements for the analog merging unit used for the merging process. Moreover, it saves on mixers and reduces the difficulty of up-conversion.

[0032] In one possible implementation, the combining module includes an analog signal combiner and a third filter; the third filter is used to filter out noise located in the interference frequency band from the third analog signal and output a noise-reduced third analog signal, the third analog signal being an analog signal obtained by digital-to-analog conversion based on the second predistortion signal; the analog signal combiner is used to generate the third predistortion signal based on the third radio frequency signal and the fourth radio frequency signal, the third radio frequency signal being a radio frequency signal obtained by up-conversion based on the noise-reduced third analog signal, the fourth radio frequency signal being a radio frequency signal obtained by up-conversion based on the fourth analog signal, and the fourth analog signal being an analog signal obtained by digital-to-analog conversion based on the first predistortion signal.

[0033] In this embodiment, digital-to-analog conversion and up-conversion are performed first, followed by the merging process. Furthermore, a filter is used before the merging process to remove noise in the third radio frequency signal located in the interference frequency band, which helps reduce the noise of the radio frequency signal to be merged, thereby reducing the noise of the merged signal. Additionally, performing up-conversion before merging, i.e., performing the merging process at the radio frequency signal stage, helps improve the accuracy of the merging operation.

[0034] In one possible implementation, the merging module further includes: at least one variable gain amplifier for adjusting the ratio between the power of the noise-reduced third analog signal and the power of the fourth analog signal input to the analog signal merging unit; or, the at least one variable gain amplifier for adjusting the ratio between the power of the third radio frequency signal and the power of the fourth radio frequency signal input to the analog signal merging unit.

[0035] In this embodiment, at least one variable gain amplifier is added to adjust the power ratio of the signal input to the analog combiner, so that the power ratio of the signal component in the main frequency band to the signal component in the interference frequency band in the output third predistortion signal is equal to the power ratio of the signal component in the main frequency band to the signal component in the interference frequency band in the first radio frequency signal, which helps to ensure the accuracy of predistortion correction.

[0036] In one possible implementation, the auxiliary distortion signal and the first baseband signal are used to train a first predistortion model, the first predistortion model is used to generate the first predistortion signal based on the second baseband signal, and the first predistortion model is located in the first predistortion module; the main distortion signal and the first baseband signal are used to train a second predistortion model, the second predistortion model is used to generate the second predistortion signal based on the second baseband signal, and the second predistortion model is located in the second predistortion module.

[0037] In one possible implementation, the frequency value of the main frequency band is greater than the frequency value of the interference frequency band.

[0038] In one possible implementation, the main frequency band is a wireless communication frequency band, and the interference frequency band is a satellite frequency band.

[0039] In this embodiment, when the main frequency band is the wireless communication band and the interfering frequency band is the satellite band, the frequency predistortion device is equipped with satellite band feedback sampling channels and wireless communication band feedback sampling channels respectively. It performs predistortion processing on signals located in different frequency bands, and then performs merging processing. This helps to eliminate signal components located in the satellite band and achieves satellite band spurious suppression.

[0040] Secondly, this application provides a frequency predistortion method applied to a transmission system, such as an NR high-frequency transmission system. In this method, a frequency predistortion device acquires a first radio frequency (RF) signal and, based on the first RF signal, acquires a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band. Then, it predistorts the second baseband signal based on the auxiliary distortion signal and the primary distortion signal, respectively, to obtain a first predistortion signal and a second predistortion signal. The first predistortion signal is located in the interference frequency band, and the second predistortion signal is located in the primary frequency band. Then, it synthesizes a third predistortion signal based on the first and second predistortion signals. The third predistortion signal is located in both the primary frequency band and the interference frequency band, and the second RF signal obtained by RF amplification of the third predistortion signal is located in the primary frequency band.

[0041] The first radio frequency signal is a nonlinear distorted radio frequency signal obtained by up-conversion and radio frequency amplification of the first baseband signal. The first baseband signal is located in the main frequency band, and the first radio frequency signal is located in the main frequency band and the interference frequency band. The signal component of the first radio frequency signal located in the interference frequency band is generated by the nonlinear distortion of the signal component of the first baseband signal located in the main frequency band.

[0042] In one possible implementation, acquiring the primary distortion signal located in the primary frequency band and the secondary distortion signal located in the interference frequency band based on the first radio frequency signal includes:

[0043] The analog signal components located in the main frequency band are filtered out from the first analog signal, and the analog signal components located in the interference frequency band in the obtained first analog signal are converted from analog to digital to obtain the main distortion signal; wherein, the first analog signal is a signal obtained by downconverting the first radio frequency signal, or the first analog signal is the first radio frequency signal.

[0044] The analog signal components located in the interference frequency band are filtered out from the second analog signal, and the analog signal components located in the main frequency band in the obtained second analog signal are converted from analog to digital to obtain the auxiliary distortion signal; wherein, the second analog signal is a signal obtained by down-converting the first radio frequency signal, or the second analog signal is the first radio frequency signal.

[0045] In one possible implementation, before performing analog-to-digital conversion, the method further includes: adjusting the first power of the analog signal component in the first analog signal located in the interference frequency band and the second power of the analog signal component in the second analog signal located in the main frequency band, so that the difference between the first power and the second power is less than a preset value.

[0046] In one possible implementation, the synthesis of a third predistorted signal based on the first predistorted signal and the second predistorted signal includes: using a digital signal combiner to synthesize the first predistorted signal and the second predistorted signal into a predistorted baseband signal; and performing digital-to-analog conversion and up-conversion processing on the predistorted baseband signal to obtain the third predistorted signal.

[0047] In this embodiment, performing the merging process at the digital signal stage helps ensure the accuracy of the merging operation and saves on digital-to-analog converters and mixers.

[0048] In one possible implementation, the synthesis of the third predistorted signal based on the first predistorted signal and the second predistorted signal includes: performing digital-to-analog conversion on the first predistorted signal and the second predistorted signal respectively to obtain a third analog signal and a fourth analog signal; filtering out noise located in the interference frequency band from the third analog signal to output a noise-reduced third analog signal; performing a merging process on the noise-reduced third analog signal and the fourth analog signal to obtain a predistorted analog signal; and performing up-conversion processing on the predistorted analog signal to obtain the third predistorted signal.

[0049] Optionally, before combining the denoised third analog signal and the fourth analog signal, the method further includes: adjusting the ratio between the power of the denoised third analog signal and the power of the fourth analog signal.

[0050] In one possible implementation, the synthesis of the third predistorted signal based on the first predistorted signal and the second predistorted signal includes: performing digital-to-analog conversion on the first predistorted signal and the second predistorted signal respectively to obtain a third analog signal and a fourth analog signal; filtering out noise located in the interference frequency band from the third analog signal to output a noise-reduced third analog signal; performing up-conversion processing on the noise-reduced third analog signal and the fourth analog signal respectively to obtain a third radio frequency signal and a fourth radio frequency signal; and performing a combining processing on the third radio frequency signal and the fourth radio frequency signal to obtain the third predistorted signal.

[0051] Optionally, before performing the merging process based on the third and fourth radio frequency signals, the method further includes: adjusting the ratio between the power of the third radio frequency signal and the power of the fourth radio frequency signal.

[0052] In one possible implementation, the predistortion processing of the second baseband signal based on the secondary distortion signal and the primary distortion signal to obtain a first predistorted signal and a second predistorted signal includes: generating the first predistorted signal based on the second baseband signal and a first predistortion model, wherein the first predistortion model is obtained by training using the secondary distortion signal and the first baseband signal; and generating the second predistorted signal based on the second baseband signal and the second predistortion model, wherein the second predistortion model is obtained by training using the primary distortion signal and the first baseband signal.

[0053] In one possible implementation, the frequency value of the main frequency band is greater than the frequency value of the interference frequency band.

[0054] In one possible implementation, the main frequency band is a wireless communication frequency band, and the interference frequency band is a satellite frequency band.

[0055] Thirdly, this application provides a transmission system including a radio frequency amplifier and a frequency predistortion device as described in any embodiment of the first aspect. Optionally, the transmission system further includes a baseband signal generation module. The baseband signal generation module is used to generate a baseband signal. The frequency predistortion device performs predistortion processing on the baseband signal to obtain a predistorted signal. The radio frequency amplifier amplifies the predistorted signal, and under the nonlinear distortion effect of the radio frequency amplifier, the signal transmitted to the antenna by the radio frequency amplifier does not exhibit nonlinear distortion.

[0056] As can be seen from the above technical solutions, this application has the following advantages:

[0057] In this application, the frequency predistortion device can acquire a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band based on a first radio frequency signal. Then, it performs predistortion processing on a second baseband signal based on the aforementioned primary distortion signal and auxiliary distortion signal to obtain a first predistortion signal and a second predistortion signal, respectively. The first predistortion signal and the second predistortion signal are then combined to form a third predistortion signal. Since the signal component in the interference frequency band of the third predistortion signal can be canceled out by the nonlinear distortion after passing through the radio frequency amplifier, the radio frequency signal provided to the antenna by the radio frequency amplifier does not contain signals in the interference frequency band, but only signals in the primary frequency band. Attached Figure Description

[0058] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0059] Figure 1A This is a system architecture diagram applicable to the frequency predistortion device in this application;

[0060] Figure 1B This is an example plot of the frequency spectrum of the nonlinear distortion signal in this application;

[0061] Figure 2 This is a schematic diagram of one embodiment of the frequency predistortion device in this application;

[0062] Figure 3A This is an example diagram of the signal components located in the interference frequency band in this application;

[0063] Figure 3B This is an example diagram of the signal components located in the main frequency band in this application;

[0064] Figure 4A This is a schematic diagram of an embodiment of the frequency segmentation module in the frequency predistortion device of this application;

[0065] Figure 4B This is a schematic diagram of another embodiment of the frequency segmentation module in the frequency predistortion device of this application;

[0066] Figure 4C This is a schematic diagram of another embodiment of the frequency segmentation module in the frequency predistortion device of this application;

[0067] Figure 4D This is a schematic diagram of another embodiment of the frequency segmentation module in the frequency predistortion device of this application;

[0068] Figure 5A This is a schematic diagram of an embodiment of the incorporation module in the frequency predistortion device of this application;

[0069] Figure 5B This is a schematic diagram of another embodiment of the incorporation module in the frequency predistortion device of this application;

[0070] Figure 5C This is a schematic diagram of another embodiment of the incorporation module in the frequency predistortion device of this application;

[0071] Figure 6A This is a schematic diagram of another embodiment of the frequency predistortion device in this application;

[0072] Figure 6B This is a schematic diagram of another embodiment of the frequency predistortion device in this application;

[0073] Figure 7 This is a flowchart of the frequency predistortion method in this application. Detailed Implementation

[0074] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0075] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0076] To facilitate understanding, the technical terms used in this application will be introduced below:

[0077] Nonlinear distortion refers to the phenomenon where the output signal of a nonlinear system undergoes a nonlinear change compared to the input signal. This nonlinear distortion includes not only nonlinear changes in the signal's power and amplitude but also nonlinear changes in the frequency band in which the signal resides. Specifically, the nonlinear change in the frequency band refers to the addition of a signal component in the output signal that is located in a new frequency band compared to the input signal. For example, if the input signal is located in frequency band A, and the output signal contains not only a signal component in frequency band A but also a signal component in frequency band B, then the signal component in frequency band B is the newly added signal component in the new frequency band. The original frequency band of the input signal (e.g., frequency band A in the example) is a useful or effective frequency band, while the newly added frequency band in the output signal (e.g., frequency band B in the example) is an unwanted or interfering frequency band. For ease of explanation, the original frequency band of the input signal is referred to as the primary frequency band, and the newly added frequency band in the output signal is referred to as the interference frequency band. It should be noted that the nonlinear distortion in this application may be nonlinear distortion caused solely by the RF amplifier, or nonlinear distortion caused by an RF amplification link consisting of devices such as digital-to-analog converters, mixers (e.g., upconverters) and RF amplifiers. No specific limitation is made here.

[0078] Digital pre-distortion refers to the distortion processing performed on the input signal before it is input to the RF amplifier. This distortion process generally occurs during the digital signal stage. The purpose of pre-distortion is to distort the input signal in a certain direction, opposite to the distortion direction of the RF amplifier (or RF link). In other words, the input signal undergoes one distortion during the pre-distortion processing stage, resulting in a pre-distorted signal. This pre-distorted signal then undergoes another distortion after passing through the RF amplifier (or RF link), resulting in the output signal. Since the two distortions are in opposite directions and of the same degree, the pre-distortion process can offset or cancel the nonlinear distortion effect of the RF amplifier (or RF link) on the signal.

[0079] Variable gain amplifier (VGA): It can amplify the power of a signal by adjusting the voltage, or it can reduce the power of a signal by adjusting the voltage. The amplification and reduction ratio is adjustable.

[0080] Analog-to-digital converter (ADC): Samples an analog signal and converts it into a digital signal. The higher the sampling rate, the more accurate the generated digital signal.

[0081] Digital-to-analog converter (DAC): Converts digital signals into analog signals.

[0082] The frequency predistortion method provided in this application can be applied to 5th generation (5G) communication technology or new radio (NR) high-frequency scenarios. For example, scenarios where signals from wireless communication frequency bands (e.g., the 26GHz band) generate signal components in satellite frequency bands (e.g., the 23.6GHz~24GHz band) due to nonlinear distortion. Based on the frequency predistortion method provided in this application, the nonlinear distortion signal components of wireless communication frequency band signals in satellite frequency bands can be effectively reduced. It is understood that the frequency predistortion method provided in this application can also be used to reduce nonlinear distortion signal components of signals from other frequency bands outside the main frequency band; specific applications are not limited here.

[0083] The frequency predistortion method provided in this application can be applied to, for example... Figure 1A The transmission system shown can also be applied to other transmission systems that may produce nonlinear distortion; specific applications are not limited here. Figure 1AIn the transmission system shown, the baseband signal generated by the baseband signal generation module 02 is transmitted to the RF amplifier PA03 after processing such as digital-to-analog conversion and up-conversion. For example... Figure 1B As shown, the signal before input to RF amplifier PA03 is located in the main frequency band. Due to the nonlinear distortion of RF amplifier PA03, the signal output from RF amplifier PA03 has signal components not only in the main frequency band but also in the interference frequency band. However, the signal components in the interference frequency band are not the desired signals and may interfere with communication. It should be understood that the signal output from RF amplifier PA03 may also be affected by the nonlinear distortion of the digital-to-analog converter (not shown) or mixer (not shown) on the RF amplification link.

[0084] It should be understood that interference bands and primary bands are relative concepts. Primary bands refer to the bands that are originally needed; interference bands refer to the bands that are originally not needed.

[0085] This application incorporates a frequency predistortion device before the RF amplifier, for example... Figure 1A As shown, a frequency predistortion device 01 is set between the baseband generation module 02 and the radio frequency amplifier PA 03. By performing predistortion processing by frequency division, the frequency components of other frequency bands generated by nonlinear distortion in the radio frequency signal are eliminated.

[0086] The following will combine Figure 2 A detailed introduction to the frequency predistortion device:

[0087] like Figure 2 The diagram shown is a structural schematic of a frequency predistortion device provided in this application. The frequency predistortion device 01 includes: a frequency segmentation module 011, a first predistortion module 012, a second predistortion module 013, and a merging module 014.

[0088] The frequency segmentation module 011 is used to acquire a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band based on a first radio frequency signal. The first radio frequency signal is a nonlinear distorted radio frequency signal obtained by up-conversion and radio frequency amplification of a first baseband signal, and this first radio frequency signal is located in both the primary and interference frequency bands. The first baseband signal is a baseband signal generated by the baseband signal generation module 02 at a historical moment. This first baseband signal is located in the primary frequency band. The signal component of the first radio frequency signal located in the interference frequency band is generated by the nonlinear distortion of the first baseband signal.

[0089] For example, the communication frequency band between the terminal device and the network device is 26 GHz, and the radio frequency signal generated in the terminal device is 26 GHz. Theoretically, if no nonlinear distortion occurs, the signal transmitted from the antenna after processing by the radio frequency amplifier should only contain the 26 GHz signal. However, in reality, the signal transmitted from the antenna after processing by the radio frequency amplifier not only contains the 26 GHz signal but also includes a 24 GHz signal. Here, 24 GHz is the satellite frequency band, and communication between the terminal device and the network device does not require the 24 GHz signal. In this example, 26 GHz can be understood as the aforementioned main frequency band, and 24 GHz can be understood as the aforementioned interference frequency band.

[0090] Specifically, the frequency segmentation module 011 receives a first radio frequency signal from the radio frequency amplifier PA 03, and obtains the signal component located in the interference frequency band based on the first radio frequency signal or based on the signal down-converted from the first radio frequency signal (e.g., Figure 3A The signal components shown) and the signal components located in the main frequency band (e.g., Figure 3B (The signal components shown); then, the frequency segmentation module 011 performs appropriate processing on the aforementioned signal components located in the main frequency band and the signal components located in the interference frequency band, respectively, to obtain the auxiliary distortion signal generated based on the signal components located in the interference frequency band and the main distortion signal generated based on the signal components located in the main frequency band.

[0091] The signal component located in the interference frequency band can be either a radio frequency (RF) signal or an intermediate frequency (IF) signal, and the signal component located in the main frequency band can also be either an RF signal or an IF signal. For example, if the frequency segmentation module 011 first performs down-conversion processing on the first RF signal, and then performs frequency segmentation processing on the down-converted signal, then the signal component located in the interference frequency band and the signal component located in the main frequency band are IF signals. Please refer to the following text for details. Figure 4B Related information. For example, if the frequency segmentation module 011 directly performs frequency segmentation processing on the first radio frequency signal, then the signal component located in the interference frequency band and the signal component located in the main frequency band are radio frequency signals. Of course, other modules or devices in the frequency predistortion device 01 will perform down-conversion processing on the radio frequency signal located in the interference frequency band and the radio frequency signal located in the main frequency band respectively; please refer to the following text for details. Figure 4C Related information.

[0092] It should be noted that the frequency predistortion device 01 performs up-conversion, down-conversion, or other frequency conversion operations on the signal during signal processing. Therefore, the frequency values ​​of the signal in the main frequency band are different at different signal processing stages, and the frequency values ​​of the signal in the interference frequency band are also different at different signal processing stages. For example, consider a first radio frequency signal containing a signal component at 26 GHz and a signal component at 24 GHz. If the down-conversion operation shifts the signal component at 26 GHz to 0 GHz and the signal component at 24 GHz to -2 GHz, then the signal component at 26 GHz and the signal component at 0 GHz after down-conversion are both signal components in the main frequency band, and the signal component at 24 GHz and the signal component at -2 GHz after down-conversion are both signal components in the interference frequency band. Therefore, this application does not limit the specific frequency value of the interference frequency band, nor does it limit the specific frequency value of the main frequency band. Furthermore, in the same signal processing stage, the frequency value of the main frequency band is generally greater than the frequency value of the interference frequency band. For example, if the main frequency band is the wireless communication frequency and the interference frequency band is the satellite frequency band, then in the same signal processing stage, the frequency value of the wireless communication frequency band is generally greater than the frequency value of the satellite frequency band.

[0093] Furthermore, the first predistortion module 012 and the second predistortion module 013 in the frequency predistortion device 01 process the second baseband signal based on the auxiliary distortion signal and the main distortion signal, respectively. Specifically, the first predistortion module 012 generates a first predistorted signal based on the second baseband signal and the auxiliary distortion signal, and this first predistorted signal is located in the interference frequency band. The second predistortion module 013 generates a second predistorted signal based on the second baseband signal and the main distortion signal, and this second predistorted signal is located in the main frequency band.

[0094] The second baseband signal is the baseband signal generated by the baseband signal generation module 02 at the current moment, and it is the baseband signal that needs to undergo pre-distortion processing. This second baseband signal is located in the main frequency band.

[0095] Specifically, the first predistortion module 012 can train a first predistortion model based on the first baseband signal and the auxiliary distortion signal. This first predistortion model is used to generate the first predistorted signal based on the second baseband signal. The second predistortion module 013 can train a second predistortion model based on the first baseband signal and the main distortion signal. This second predistortion model is used to generate the second predistorted signal based on the second baseband signal.

[0096] Subsequently, the merging module 014 in the frequency predistortion device 01 is used to generate a third predistortion signal based on the first predistortion signal and the second predistortion signal. The third predistortion signal is located in the main frequency band and the interference frequency band. The second radio frequency signal obtained by amplifying the third predistortion signal is located in the main frequency band. It can be understood that the third predistortion signal is a signal that can cancel the nonlinear distortion effect of the radio frequency amplifier PA 03. The second radio frequency signal obtained after inputting the third predistortion signal into the radio frequency amplifier PA 03 will only contain the signal located in the main frequency band and will not generate the signal located in the interference frequency band.

[0097] In this embodiment, the frequency predistortion device 01 can acquire a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band based on the first radio frequency signal. Then, it performs predistortion processing on the second baseband signal based on the aforementioned primary distortion signal and auxiliary distortion signal to obtain a first predistortion signal and a second predistortion signal, and combines the first predistortion signal and the second predistortion signal into a third predistortion signal. Since the signal component located in the interference frequency band in the third predistortion signal can be canceled out by the nonlinear distortion after passing through the radio frequency amplifier, the radio frequency signal provided to the antenna by the radio frequency amplifier does not contain the signal located in the interference frequency band, but only the signal located in the primary frequency band.

[0098] It should be noted that the frequency predistortion device in this application divides the signal by frequency, which differs from the conventional approach of dividing the signal by amplitude or power. Conventional approaches that divide the signal by amplitude or power and perform predistortion processing separately cannot solve the problem of suppressing signal components in interference frequency bands.

[0099] Specifically, when the primary frequency band is the wireless communication band and the interfering frequency band is the satellite band, the frequency predistortion device has separate satellite band feedback sampling channels and wireless communication band feedback sampling channels. These channels perform predistortion processing on signals located in different frequency bands before merging. This helps eliminate signal components located in the satellite band and achieves satellite band spurious suppression.

[0100] The above will be discussed below. Figure 2 The frequency segmentation module 011 in the middle will be further introduced:

[0101] Specifically, the frequency segmentation module 011 includes at least one filter. This frequency segmentation module 011 can use one or more filters to segment the first radio frequency signal (or the down-converted signal of the first radio frequency signal) by frequency during the analog signal stage to obtain, for example, Figure 3A The signal components located in the interference frequency band shown are as follows: Figure 3B The signal components shown are located in the main frequency band.

[0102] In one possible implementation, such asFigure 4A As shown, the frequency segmentation module 011 includes a first filter 101 and a second filter 102, which are connected in parallel. The first filter 101 is used to filter out the analog signal components located in the main frequency band from the first analog signal, obtaining the analog signal components located in the interference frequency band from the first analog signal. The second filter 102 is used to filter out the analog signal components located in the interference frequency band from the second analog signal, obtaining the analog signal components located in the main frequency band from the second analog signal.

[0103] Wherein, the first analog signal is a signal obtained by down-converting the first radio frequency signal; or, the first analog signal is the first radio frequency signal; the second analog signal is a signal obtained by down-converting the first radio frequency signal; or, the second analog signal is the first radio frequency signal. That is to say, the frequency segmentation module 011 can first perform down-conversion processing on the first radio frequency signal and then segment it according to frequency; or it can first segment it according to frequency and then perform down-conversion processing on the signal component located in the main frequency band and the signal component located in the interference frequency band respectively.

[0104] In one optional implementation, the frequency segmentation module 011 first performs down-conversion processing on the first radio frequency signal, and then segments it according to frequency. For example, the frequency segmentation module 011 can employ methods such as... Figure 4B The implementation shown is as follows. A mixer 301 is disposed on the side of the first filter 101 closest to the RF amplifier, and a mixer 302 is disposed on the side of the second filter 101 closest to the RF amplifier. In this case, the first analog signal is a signal obtained by down-converting the first RF signal, and the second analog signal is also a signal obtained by down-converting the first RF signal. That is, the first RF signal is transmitted to mixers 301 and 302 respectively, and down-converted to obtain the first analog signal output by mixer 301 and the second analog signal output by mixer 302. The first analog signal and the second analog signal may not be the same signal, because the degree of down-conversion of the first analog signal and the degree of down-conversion of the second analog signal may not be the same.

[0105] It should be understood that downconversion can be understood as modulating a high-frequency or radio-frequency signal to a sampling frequency band acceptable to the digital-to-analog converter. Downconversion can be modulating a signal located at 26 GHz to 0 GHz and a signal located at 24 GHz to -2 GHz; it can also be modulating a signal located at 26 GHz to 2 GHz and a signal located at 24 GHz to 0 GHz; it can also modulate a signal located at 26 GHz and a signal located at 24 GHz to other frequency bands, which is not limited here.

[0106] In another optional implementation, the frequency segmentation module 011 first segments the signal according to frequency, and then performs down-conversion processing on the signal components located in the main frequency band and the signal components located in the interference frequency band respectively. For example, the frequency segmentation module 011 can adopt the following... Figure 4C The implementation shown is as follows. A mixer 301 is located on the side of the first filter 101 furthest from the RF amplifier, and a mixer 302 is located on the side of the second filter 102 furthest from the RF amplifier. In this case, both the first analog signal and the second analog signal are the first RF signal. That is, the first RF signal is transmitted to the first filter 101 and the second filter 102 respectively. Then, mixer 301 performs down-conversion processing on the signal component located in the interference frequency band, and mixer 302 performs down-conversion processing on the signal component located in the main frequency band.

[0107] Furthermore, the frequency segmentation module 011 also includes an analog-to-digital converter (ADC). Specifically, the frequency segmentation module 011 further includes a first ADC 201 and a second ADC 202. The first ADC 201 is used to sample the analog signal components in the first analog signal located in the interference frequency band to obtain the auxiliary distortion signal. The second ADC 202 is used to sample the analog signal components in the second analog signal located in the main frequency band to obtain the main distortion signal.

[0108] In this embodiment, during the analog signal processing stage, different filters are used to filter the first and second analog signals respectively, obtaining the analog signal component in the first analog signal located in the interference frequency band and the analog signal component in the second analog signal located in the main frequency band. Then, the two signal components are converted from analog to digital to obtain a secondary distortion signal and a primary distortion signal, so that the first predistortion module 012 and the second predistortion module 013 can perform predistortion processing respectively. Since predistortion processing is performed separately for the distorted signals in different frequency bands—that is, predistortion processing is performed separately for the signal component located in the main frequency band and the signal component located in the interference frequency band—the predistortion processing is not affected by signal components in other frequency bands. For example, when predistorting the signal component located in the main frequency band, it is not affected by signal components in the interference frequency band, and when predistorting the signal component located in the interference frequency band, it is not affected by signal components in the main frequency band. Therefore, this helps to ensure the accuracy of the generated predistorted signal.

[0109] It should be noted that when the power of the signal component located in the interference band is much smaller than the power of the signal component located in the main band, a filter for filtering the signal component located in the interference band does not need to be set on the link for acquiring the main distorted signal (e.g., as mentioned above). Figure 4A ,Figure 4B as well as Figure 4C The second filter 102 in the frequency segmentation module 101 includes a first filter 101 for filtering out signal components located in the main frequency band. When the second filter 102 is not set, the first RF signal is down-converted by the mixer 302 and then input to the second ADC 202. Since the power of the signal components located in the interference frequency band is much smaller than the power of the signal components located in the main frequency band, the signal after analog-to-digital conversion by the second ADC 202 can be regarded as having only a high-power main distortion signal, or the low-power auxiliary distortion signal in the signal after analog-to-digital conversion by the second ADC 202 has almost no impact on the subsequent calculation of the second pre-distortion signal.

[0110] At this time, the first analog-to-digital converter module ADC 201 is used to sample the analog signal component located in the interference frequency band of the first analog signal to obtain the auxiliary distortion signal; the second analog-to-digital converter module ADC 202 is used to sample the signal obtained by down-converting the first radio frequency signal to obtain the main distortion signal.

[0111] Based on the aforementioned implementation, the frequency segmentation module 011 can also be equipped with a variable gain amplifier (VGA) to amplify the power of the signal input to the analog-to-digital converter (ADC), so that the ADC can achieve full-amplitude sampling during sampling, which is beneficial to improving sampling accuracy and improving the accuracy of analog-to-digital conversion.

[0112] It should be understood that both variable gain amplifiers (VGA) and radio frequency amplifiers (PA) amplify power. However, the variable gain amplifier has a smaller amplification degree and operates in the linear region, while the radio frequency amplifier has a larger amplification degree and operates in the nonlinear region.

[0113] In one possible implementation, such as Figure 4D As shown, the frequency segmentation module 011 also includes a first variable gain amplifier VGA 401 and a second variable gain amplifier VGA 402. The first VGA 401 is located between the first filter 101 and the first ADC 201, and the second VGA 402 is located between the second filter 102 and the second ADC 202. When the second filter 102 is not set in the frequency segmentation module 011, the second VGA is located between the second ADC 202 and the mixer 302. Specifically, the first VGA 401 amplifies the analog signal component of the first analog signal input to the first ADC 201 located in the interference frequency band; the second VGA 402 amplifies the analog signal component of the second analog signal input to the second ADC 202 located in the main frequency band.

[0114] It should be understood that Figure 4D The implementation shown is in Figure 4BThe first VGA 401 and the second VGA 402 are added based on the embodiment shown; this application can also be implemented in... Figure 4C The aforementioned first VGA 401 and second VGA 402 are added to the implementation shown, and the details will not be elaborated here.

[0115] Optionally, since the power of signals located in different frequency bands after being processed by filters or mixers may not be the same, the amplification ratios of the two VGAs set in the aforementioned frequency segmentation module 011 are generally different.

[0116] Optionally, if the ADCs connected to the two VGAs have the same configuration, the amplification ratio of the two VGAs can be set according to the power ratio of signals located in different frequency bands, so that the power of signals located in different channels after amplification is the same or similar. This simplifies the frequency predistortion device 01 and also enables the two ADCs to achieve full-sampling when sampling signals, improving the signal-to-noise ratio of signal sampling and increasing the conversion efficiency of subsequent analog-to-digital conversion.

[0117] For example, if Figure 4D If the configurations of the first ADC 201 and the second ADC 202 shown are the same, then the amplification ratio of the second VGA 402 and the amplification ratio of the first VGA 401 can be determined based on the power of the signal component located in the interference frequency band (e.g., the analog signal component of the first analog signal located in the interference frequency band) and the power of the signal component located in the main frequency band (e.g., the analog signal component of the second analog signal located in the main frequency band).

[0118] For example, if the power of the signal component located in the interference frequency band (e.g., the analog signal component of the first analog signal located in the interference frequency band) is less than the power of the signal component located in the main frequency band (e.g., the analog signal component of the second analog signal located in the main frequency band), the amplification ratio of the second VGA 402 can be set to be less than the amplification ratio of the first VGA 401, so that the power of the signal entering the first ADC 201 is similar to the power of the signal entering the second ADC 202.

[0119] In this embodiment, because the signal components with relatively low power, i.e., those located in the interference frequency band, can be amplified, it is beneficial for the first ADC 201 to achieve full-amplitude sampling, thereby improving the signal-to-noise ratio of the signal sampled in the interference frequency band, increasing the dynamic range of pre-distortion correction for the signal in the interference frequency band, improving the accuracy of analog-to-digital conversion of the signal components in the interference frequency band, and ultimately improving the accuracy of the output auxiliary distortion signal. Optionally, when the interference frequency band is a satellite frequency band and the main frequency band is a wireless communication frequency band, it is beneficial to improve the dynamic range of satellite frequency band pre-distortion correction.

[0120] Furthermore, the merging module 014 in this application can be implemented in various ways. The merging module 014 can merge a predistorted digital signal located in the interference frequency band (e.g., the aforementioned first predistorted signal) and a predistorted digital signal located in the main frequency band (e.g., the aforementioned second predistorted signal) during the digital signal processing stage. Alternatively, it can merge a predistorted analog signal located in the interference frequency band (e.g., an analog signal processed by digital-to-analog conversion, etc., based on the aforementioned first predistorted signal) and a predistorted analog signal located in the main frequency band (e.g., an analog signal processed by digital-to-analog conversion, etc., based on the aforementioned second predistorted signal) during the analog signal processing stage. These will be described in detail below:

[0121] In one possible implementation, the merging module 014 performs merging processing during the digital signal processing stage. In this case, the merging module 014 includes a digital signal merging unit. This digital signal merging unit is used to combine the first predistorted signal and the second predistorted signal into a predistorted baseband signal, which is located in both the main frequency band and the interference frequency band. After the predistorted baseband signal undergoes digital-to-analog conversion and up-conversion processing, the aforementioned third predistorted signal can be obtained. This third predistorted signal is a radio frequency (RF) signal. After the third predistorted signal undergoes nonlinear distortion by an RF amplifier, the resulting second RF signal is located in the main frequency band and does not contain signals located in the interference frequency band.

[0122] For example, the merging module 014 can adopt the following... Figure 5A The example implementation is shown. The combining module 014 includes a digital signal combiner. Optionally, the combining module 014 further includes a first DAC 501 and a mixer 303. The digital signal combiner combines the first predistorted signal and the second predistorted signal into a predistorted baseband signal; the first DAC 501 converts the predistorted baseband signal received from the digital signal combiner into a predistorted analog signal; and the mixer 303 up-converts the predistorted analog signal obtained from the first DAC 501 to obtain a third predistorted signal.

[0123] In this embodiment, performing the merging process at the digital signal stage helps ensure the accuracy of the merging operation and saves on digital-to-analog converters and mixers.

[0124] In another possible implementation, the incorporation module 014 performs incorporation processing during the analog signal processing stage. In this case, the incorporation module 014 includes an analog signal incorporator. This analog signal incorporator is used to incorporate a predistorted analog signal located in the interference frequency band and a predistorted analog signal located in the main frequency band. Then, the predistorted analog signal obtained after incorporation processing is up-converted to obtain the aforementioned third predistorted signal.

[0125] Optionally, a filter can be set before the merging operation to remove noise from the predistorted analog signal located in the main frequency band and / or the predistorted analog signal located in the interference frequency band. Optionally, setting a filter to remove noise in the interference frequency band from the predistorted analog signal located in the main frequency band helps to make the predistorted signal obtained after the merging operation more accurate. This, in turn, allows the third predistorted signal, after being input to the RF amplifier, to more accurately cancel the signal components located in the interference frequency band, so that the output second RF signal does not contain signal components located in the interference frequency band.

[0126] For example, the merging module 014 can adopt the following... Figure 5B The example implementation is shown. The combining module 014 includes an analog signal combiner and a third filter 202. Optionally, modules or devices connected to the third filter 202 may also include a second DAC 502, a third DAC 503, and a mixer 304, which can be understood as part of the combining module 014. Specifically, the second DAC 502 obtains a third analog signal based on a second predistorted signal via digital-to-analog conversion. This third analog signal is transmitted to the third filter 202, which filters out noise located in the interference frequency band from the third analog signal, outputting a noise-reduced third analog signal. Simultaneously, the third DAC 503 obtains a fourth analog signal based on a first predistorted signal via digital-to-analog conversion, and this fourth analog signal is transmitted to the analog signal combiner. The analog signal combiner is used to generate a predistorted analog signal based on the noise-reduced third and fourth analog signals. The third predistorted signal is a radio frequency signal obtained by up-conversion based on the predistorted analog signal.

[0127] In this example, digital-to-analog conversion is performed first, followed by the merging process. Furthermore, a filter is used before merging to remove noise in the interference frequency band of the third analog signal, which helps reduce the noise of the intermediate frequency (IF) signal to be merged, thereby reducing the noise of the merged signal. Additionally, performing digital-to-analog conversion and merging before up-conversion—that is, performing merging at the IF signal stage—reduces the complexity of the analog merging unit and lowers the requirements for the analog merging unit used for the merging process. It also saves on mixers and reduces the difficulty of up-conversion.

[0128] For example, the merging module 014 can adopt the following... Figure 5CThe example implementation is shown. The merging module 014 includes an analog signal merging unit and a third filter 202. Optionally, modules or devices connected to the third filter 202 may also include: a second DAC 502, a third DAC 503, a mixer 305, and a mixer 306, which can be understood as part of the merging module 014. Specifically, the second DAC 502 obtains a third analog signal based on a second predistorted signal via digital-to-analog conversion. This third analog signal is transmitted to the third filter 202, which filters out noise located in the interference frequency band from the third analog signal, outputting a noise-reduced third analog signal. Then, the mixer 305 up-converts the noise-reduced third analog signal to obtain a third radio frequency signal located in the main frequency band. Simultaneously, the third DAC 503 obtains a fourth analog signal based on a first predistorted signal via digital-to-analog conversion, and this fourth analog signal is transmitted to the analog signal merging unit. Then, mixer 306 up-converts the fourth analog signal to obtain a fourth radio frequency signal located in the interference frequency band. The analog signal combiner generates the third predistortion signal based on the third and fourth radio frequency signals.

[0129] In this example, digital-to-analog conversion and up-conversion are performed before the merging process. Furthermore, a filter is used to remove noise in the interference frequency band of the third RF signal before merging, which helps reduce the noise of the RF signal to be merged, and thus reduces the noise of the merged signal. In addition, performing up-conversion before merging, that is, performing merging at the RF signal stage, helps improve the accuracy of the merging operation.

[0130] Optionally, if the power of the signal component in the first radio frequency signal located in the interference band is different from the power of the signal component located in the main frequency, at least one variable gain amplifier can be set before the analog combiner to adjust the power ratio of the signal input to the analog combiner.

[0131] For example, such as Figure 5B As shown, a third VGA 403 and a fourth VGA 404 are configured before the analog combiner to adjust the ratio between the power of the third analog signal and the power of the fourth analog signal used for noise reduction in the input analog signal combiner. For example, if the power of the signal component in the first radio frequency signal located in the interference band is less than the power of the signal component located in the main frequency band, then the third VGA 403 and the fourth VGA 404 are used to adjust the power of the fourth analog signal to be less than the power of the noise-reduced third analog signal. For example, if the ratio of the power of the signal component in the first radio frequency signal located in the interference band to the power of the signal component located in the main frequency band is 1:5, then the third VGA 403 and the fourth VGA 404 are used to adjust the ratio of the power of the fourth analog signal to the power of the noise-reduced third analog signal to 1:5.

[0132] It should be understood that during the adjustment process, the third VGA 403 may amplify the power or reduce the power; the fourth VGA 404 may also amplify the power or reduce the power. For example, when the power of the noise-reduced third analog signal output by the third filter 202 is equal to the power of the fourth analog signal, the third VGA can be set to appropriately reduce the fourth analog signal, or the fourth VGA can be set to appropriately amplify the noise-reduced third analog signal; the specifics are not limited here.

[0133] For example, such as Figure 5C As shown, a third VGA 403 and a fourth VGA 404 are configured before the analog signal combiner to adjust the ratio between the power of the third RF signal and the power of the fourth RF signal input to the analog signal combiner. For example, if the power of the signal component in the first RF signal located in the interference band is less than the power of the signal component located in the main frequency band, then the third VGA 403 and the fourth VGA 404 are used to adjust the power of the fourth RF signal to be less than the power of the third RF signal. For example, if the ratio of the power of the signal component in the first RF signal located in the interference band to the power of the signal component located in the main frequency band is 1:6, then the third VGA 403 and the fourth VGA 404 are used to adjust the ratio of the power of the fourth RF signal to the power of the third RF signal to 1:6.

[0134] It should be understood that during the adjustment process, the third VGA 403 may amplify the power or reduce the power; the fourth VGA 404 may amplify the power or reduce the power. For example, when the power of the third RF signal output by the third filter 202 is equal to the power of the fourth RF signal, the third VGA can be set to appropriately reduce the fourth RF signal, or the fourth VGA can be set to appropriately amplify the third RF signal; the specifics are not limited here.

[0135] It should be noted that the aforementioned Figure 5B and Figure 5C In the example shown, the third DAC 503 can be a higher-frequency digital-to-analog converter (DAC) or a lower-frequency DAC. When the third DAC 503 is a lower-frequency DAC, a modem (mod) can be placed after the third DAC 503 to increase the frequency, thereby reducing the frequency requirement on the third DAC 503.

[0136] It should be understood that the merge module 014 mentioned in this application is only a module based on logical function for the convenience of introduction. The merge module can be understood as including the merger and other related structures or devices, or it may exclude other related structures or devices other than the merger from being included in the merge module 014. This application does not make any specific limitation.

[0137] It should be understood that Figure 5A , Figure 5B as well as Figure 5C Any of the implementation methods can be combined with the aforementioned Figure 2 Combine, Figure 4A , Figure 4B , Figure 4C as well as Figure 4D Any of the implementation methods can be compared with the aforementioned Figure 2 Combine.

[0138] For example, if the frequency segmentation module 011 adopts Figure 4D The example implementation shown uses module 014. Figure 5A The example shown illustrates that the structure of the frequency predistortion device 01 can be as follows: Figure 6A As shown. Regarding Figure 6A Please refer to the relevant introductions above for the functions of each module; they will not be repeated here.

[0139] For example, if the frequency segmentation module 011 adopts Figure 4D The example implementation shown uses module 014. Figure 5B The example shown illustrates that the structure of the frequency predistortion device 01 can be as follows: Figure 6B As shown. Regarding Figure 6B Please refer to the relevant introductions above for the functions of each module; they will not be repeated here.

[0140] Furthermore, based on the combination of the aforementioned implementation methods, there are many other ways to achieve this, which will not be listed here.

[0141] like Figure 7 As shown, this application also provides a frequency predistortion method, in which the frequency predistortion device can perform the following steps:

[0142] Step 701: Obtain the first radio frequency signal.

[0143] The first radio frequency (RF) signal is a nonlinear distorted RF signal obtained by up-converting and amplifying the first baseband signal. The first baseband signal is located in the main frequency band, and the first RF signal is located in both the main frequency band and the interference frequency band. The signal component of the first RF signal located in the interference frequency band is generated by the nonlinear distortion of the signal component of the first baseband signal located in the main frequency band.

[0144] Optionally, the frequency value of the primary frequency band is greater than the frequency value of the interfering frequency band. Optionally, the primary frequency band is a wireless communication frequency band, and the interfering frequency band is a satellite frequency band. For details, please refer to the preceding text. Figure 2 The relevant descriptions in the corresponding embodiments.

[0145] Step 702: Based on the first radio frequency signal, obtain the main distortion signal located in the main frequency band and the auxiliary distortion signal located in the interference frequency band.

[0146] In one possible implementation, the frequency predistortion device can first perform a filtering operation on the first radio frequency signal to obtain the signal component in the main frequency band and the signal component in the interference frequency band of the first radio frequency signal. In this case, the main distortion signal can be understood as the signal obtained by performing a series of processes such as down-conversion and analog-to-digital conversion on the signal component in the main frequency band of the first radio frequency signal. The auxiliary distortion signal can be understood as the signal obtained by performing a series of processes such as down-conversion and analog-to-digital conversion on the signal component in the interference frequency band of the first radio frequency signal.

[0147] In another possible implementation, the frequency predistortion device can first perform down-conversion processing on the first radio frequency signal, and then perform filtering to obtain the signal component in the main frequency band of the signal obtained by down-conversion of the first radio frequency signal and the signal component in the interference frequency band of the signal obtained by down-conversion of the first radio frequency signal. In this case, the main distortion signal can be understood as the signal obtained by performing analog-to-digital conversion and other processing on the signal component in the main frequency band of the signal obtained by down-conversion of the first radio frequency signal. The auxiliary distortion signal can be understood as the signal obtained by performing analog-to-digital conversion and other processing on the signal component in the interference frequency band of the signal obtained by down-conversion of the first radio frequency signal.

[0148] Specifically, the frequency predistortion device filters out analog signal components located in the main frequency band from the first analog signal, and performs analog-to-digital conversion on the analog signal components located in the interference frequency band in the obtained first analog signal to obtain the main distortion signal. Simultaneously, it filters out analog signal components located in the interference frequency band from the second analog signal, and performs analog-to-digital conversion on the analog signal components located in the main frequency band in the obtained second analog signal to obtain the auxiliary distortion signal. The first analog signal is either a signal obtained by down-converting the first radio frequency signal, or the first analog signal is the first radio frequency signal; the second analog signal is either a signal obtained by down-converting the first radio frequency signal, or the second analog signal is the first radio frequency signal.

[0149] Optionally, before performing analog-to-digital conversion, the frequency predistortion device can adjust the first power of the analog signal component in the first analog signal located in the interference frequency band and the second power of the analog signal component in the second analog signal located in the main frequency band, so that the difference between the first power and the second power is less than a preset value.

[0150] Step 703: Perform pre-distortion processing on the second baseband signal based on the auxiliary distortion signal and the main distortion signal respectively to obtain the first pre-distortion signal and the second pre-distortion signal.

[0151] The first predistortion signal is located in the interference frequency band, and the second predistortion signal is located in the main frequency band.

[0152] Specifically, the frequency predistortion device can train a first predistortion model based on a first baseband signal and a secondary distortion signal. This first predistortion model is used to generate the first predistorted signal based on the second baseband signal. Furthermore, the frequency predistortion device can also train a second predistortion model based on the first baseband signal and a primary distortion signal. This second predistortion model is used to generate the second predistorted signal based on the second baseband signal.

[0153] Step 704: Synthesize a third predistorted signal based on the first predistorted signal and the second predistorted signal.

[0154] The third predistortion signal is located in both the main frequency band and the interference frequency band. The second radio frequency signal obtained by amplifying the third predistortion signal is located in the main frequency band and does not contain any signal components located in the interference frequency band. This can be understood as the third predistortion signal being capable of canceling the nonlinear distortion effect of the radio frequency amplifier. The second radio frequency signal obtained after inputting the third predistortion signal into the radio frequency amplifier will only contain signals located in the main frequency band and will not generate signals located in the interference frequency band.

[0155] Specifically, the frequency predistortion device can generate the aforementioned third predistortion signal using any of the following implementation methods:

[0156] In one optional implementation, the frequency predistortion device uses a digital signal combiner to combine the first predistortion signal and the second predistortion signal into a predistortion baseband signal. Then, the predistortion baseband signal is subjected to digital-to-analog conversion and up-conversion processing to obtain the third predistortion signal.

[0157] In this embodiment, performing the merging process at the digital signal stage helps ensure the accuracy of the merging operation and saves on digital-to-analog converters and mixers.

[0158] In another optional embodiment, the frequency predistortion device performs digital-to-analog conversion on the first and second predistortion signals respectively to obtain a third analog signal and a fourth analog signal. Then, noise located in the interference frequency band is filtered out from the third analog signal to output a noise-reduced third analog signal. Next, the noise-reduced third and fourth analog signals are combined to obtain a predistorted analog signal. Finally, the predistorted analog signal is up-converted to obtain the third predistorted signal.

[0159] Optionally, before combining the noise-reduced third and fourth analog signals, the frequency predistortion device may adjust the ratio between the power of the noise-reduced third analog signal and the power of the fourth analog signal, such that the ratio of the power of the noise-reduced third analog signal to the power of the fourth analog signal is equal to the ratio of the power of the signal component in the main frequency band to the power of the signal component in the interference frequency band of the first radio frequency signal.

[0160] In this embodiment, digital-to-analog conversion is performed first, followed by the merging process. Furthermore, a filter is used before the merging process to remove noise in the interference frequency band of the third analog signal, which helps reduce the noise of the intermediate frequency signal to be merged, thereby reducing the noise of the merged signal. Additionally, performing digital-to-analog conversion and merging before up-conversion—that is, performing the merging process at the intermediate frequency signal stage—reduces the complexity of the analog merging unit and lowers the requirements for the analog merging unit used for the merging process. Moreover, it saves on mixers and reduces the difficulty of up-conversion.

[0161] In another optional embodiment, the frequency predistortion device performs digital-to-analog conversion on the first predistortion signal and the second predistortion signal respectively to obtain a third analog signal and a fourth analog signal. Then, noise located in the interference frequency band is filtered out from the third analog signal to output a noise-reduced third analog signal. Then, the noise-reduced third analog signal and the fourth analog signal are up-converted respectively to obtain a third radio frequency signal and a fourth radio frequency signal. Then, the third radio frequency signal and the fourth radio frequency signal are combined to obtain the third predistortion signal.

[0162] Optionally, before performing the merging process based on the third radio frequency signal and the fourth radio frequency signal, the frequency predistortion device may further adjust the ratio between the power of the third radio frequency signal and the power of the fourth radio frequency signal, so that the ratio of the power of the third radio frequency signal to the power of the fourth radio frequency signal is equal to the ratio of the power of the signal component located in the main frequency band of the first radio frequency signal to the power of the signal component located in the interference frequency band.

[0163] In this embodiment, digital-to-analog conversion and up-conversion are performed first, followed by the merging process. Furthermore, a filter is used before the merging process to remove noise in the third radio frequency signal located in the interference frequency band, which helps reduce the noise of the radio frequency signal to be merged, thereby reducing the noise of the merged signal. Additionally, performing up-conversion before merging, i.e., performing the merging process at the radio frequency signal stage, helps improve the accuracy of the merging operation.

[0164] In this embodiment, the frequency predistortion device can acquire a primary distortion signal located in the primary frequency band and an auxiliary distortion signal located in the interference frequency band based on the first radio frequency signal. Then, it performs predistortion processing on the second baseband signal based on the aforementioned primary distortion signal and auxiliary distortion signal to obtain a first predistortion signal and a second predistortion signal, respectively. The first predistortion signal and the second predistortion signal are then combined into a third predistortion signal. Since the signal component located in the interference frequency band in the third predistortion signal can be canceled out by the nonlinear distortion after passing through the radio frequency amplifier, the radio frequency signal provided to the antenna by the radio frequency amplifier does not contain signals located in the interference frequency band, but only signals located in the primary frequency band.

[0165] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0166] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0167] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0168] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A frequency predistortion device, characterized in that, include: The frequency segmentation module is used to acquire a main distortion signal located in the main frequency band and an auxiliary distortion signal located in the interference frequency band based on a first radio frequency signal. The first radio frequency signal is a nonlinear distortion radio frequency signal obtained by up-conversion and radio frequency amplification of a first baseband signal. The first baseband signal is located in the main frequency band. The first radio frequency signal is located in both the main frequency band and the interference frequency band. The signal component of the first radio frequency signal located in the interference frequency band is generated by the nonlinear distortion of the signal component of the first baseband signal located in the main frequency band. A first predistortion module is used to generate a first predistortion signal based on a second baseband signal and the auxiliary distortion signal, wherein the first predistortion signal is located in the interference frequency band; The second predistortion module is used to generate a second predistortion signal based on the second baseband signal and the main distortion signal, wherein the second predistortion signal is located in the main frequency band; The module is used to generate a third predistorted signal based on the first predistorted signal and the second predistorted signal. The third predistorted signal is located in the main frequency band and the interference frequency band. The second radio frequency signal obtained by radio frequency amplification of the third predistorted signal is located in the main frequency band.

2. The frequency predistortion device according to claim 1, characterized in that, The frequency segmentation module includes at least one filter; The first filter in the at least one filter is used to filter out the analog signal component located in the main frequency band from the first analog signal to obtain the analog signal component located in the interference frequency band in the first analog signal; Wherein, the first analog signal is a signal obtained by down-converting the first radio frequency signal; or, the first analog signal is the first radio frequency signal.

3. The frequency predistortion device according to claim 2, characterized in that, The second filter in the at least one filter is used to filter out the analog signal component located in the interference frequency band from the second analog signal to obtain the analog signal component located in the main frequency band in the second analog signal; Wherein, the second analog signal is a signal obtained by down-converting the first radio frequency signal; or, the second analog signal is the first radio frequency signal.

4. The frequency predistortion device according to claim 3, characterized in that, The frequency segmentation module further includes: The first analog-to-digital conversion module is used to sample the analog signal components located in the interference frequency band of the first analog signal to obtain the auxiliary distortion signal; The second analog-to-digital conversion module is used to sample the analog signal components located in the main frequency band of the second analog signal to obtain the main distortion signal.

5. The frequency predistortion device according to claim 2, characterized in that, The frequency segmentation module further includes: The first analog-to-digital conversion module is used to sample the analog signal components located in the interference frequency band of the first analog signal to obtain the auxiliary distortion signal; The second analog-to-digital conversion module is used to sample the signal obtained by down-conversion of the first radio frequency signal to obtain the main distortion signal.

6. The frequency predistortion device according to claim 4, characterized in that, The frequency segmentation module further includes: A first variable gain amplifier is used to amplify the analog signal component of the first analog signal input to the first analog-to-digital converter located in the interference frequency band; The second variable gain amplifier is used to amplify the analog signal component of the second analog signal input to the second analog-to-digital converter that is located in the main frequency band; The amplification ratio of the second variable gain amplifier is different from that of the first variable gain amplifier.

7. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The merging module includes a digital signal merging unit; The digital signal combiner is used to combine the first predistorted signal and the second predistorted signal into a predistorted baseband signal. The frequency range of the predistorted baseband signal includes the main frequency band and the interference frequency band. The third predistorted signal is a signal obtained by digital-to-analog conversion and up-conversion of the predistorted baseband signal.

8. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The incorporation module includes an analog signal incorporator and a third filter; The third filter is used to filter out noise located in the interference frequency band from the third analog signal and output a noise-reduced third analog signal. The third analog signal is an analog signal obtained by digital-to-analog conversion based on the second predistortion signal. The analog signal combiner is used to generate a predistorted analog signal based on the noise-reduced third and fourth analog signals. The fourth analog signal is an analog signal obtained by digital-to-analog conversion based on the first predistorted signal, and the third predistorted signal is a radio frequency signal obtained by up-conversion based on the predistorted analog signal.

9. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The incorporation module includes an analog signal incorporator and a third filter; The third filter is used to filter out noise located in the interference frequency band from the third analog signal and output a noise-reduced third analog signal. The third analog signal is an analog signal obtained by digital-to-analog conversion based on the second predistortion signal. The analog signal combiner is used to generate the third predistortion signal based on the third radio frequency signal and the fourth radio frequency signal. The third radio frequency signal is a radio frequency signal obtained by up-conversion based on the noise-reduced third analog signal. The fourth radio frequency signal is a radio frequency signal obtained by up-conversion based on the fourth analog signal. The fourth analog signal is an analog signal obtained by digital-to-analog conversion based on the first predistortion signal.

10. The frequency predistortion device according to claim 8, characterized in that, The merging module also includes: At least one variable gain amplifier is provided for adjusting the ratio between the power of the noise-reduced third analog signal and the power of the fourth analog signal input to the analog signal combiner. or, The at least one variable gain amplifier is used to adjust the ratio between the power of the third radio frequency signal and the power of the fourth radio frequency signal input to the analog signal combiner.

11. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The auxiliary distortion signal and the first baseband signal are used to train the first predistortion model. The first predistortion model is used to generate the first predistortion signal based on the second baseband signal. The first predistortion model is located in the first predistortion module. The main distortion signal and the first baseband signal are used to train the second predistortion model. The second predistortion model is used to generate the second predistortion signal based on the second baseband signal. The second predistortion model is located in the second predistortion module.

12. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The frequency value of the main frequency band is greater than the frequency value of the interference frequency band.

13. The frequency predistortion device according to any one of claims 1 to 6, characterized in that, The main frequency band is a wireless communication frequency band, and the interference frequency band is a satellite frequency band.

14. A frequency predistortion method, characterized in that, include: A first radio frequency signal is acquired. The first radio frequency signal is a nonlinear distorted radio frequency signal obtained by up-conversion and radio frequency amplification of a first baseband signal. The first baseband signal is located in the main frequency band. The first radio frequency signal is located in the main frequency band and the interference frequency band. The signal component of the first radio frequency signal located in the interference frequency band is generated by the signal component of the first baseband signal located in the main frequency band due to the nonlinear distortion. Based on the first radio frequency signal, the main distortion signal located in the main frequency band and the auxiliary distortion signal located in the interference frequency band are obtained; The second baseband signal is predistorted based on the auxiliary distortion signal and the main distortion signal respectively to obtain a first predistorted signal and a second predistorted signal. The first predistorted signal is located in the interference frequency band, and the second predistorted signal is located in the main frequency band. A third predistorted signal is synthesized based on the first predistorted signal and the second predistorted signal. The third predistorted signal is located in the main frequency band and the interference frequency band. The second radio frequency signal obtained by radio frequency amplification of the third predistorted signal is located in the main frequency band.

15. The method according to claim 14, characterized in that, The step of acquiring the primary distortion signal located in the primary frequency band and the secondary distortion signal located in the interference frequency band based on the first radio frequency signal includes: The analog signal components located in the main frequency band are filtered out from the first analog signal, and the analog signal components located in the interference frequency band in the obtained first analog signal are subjected to analog-to-digital conversion to obtain the main distortion signal; wherein, the first analog signal is a signal obtained by down-converting the first radio frequency signal, or the first analog signal is the first radio frequency signal; The analog signal components located in the interference frequency band are filtered out from the second analog signal, and the analog signal components located in the main frequency band in the obtained second analog signal are converted from analog to digital to obtain the auxiliary distortion signal; wherein, the second analog signal is a signal obtained by down-converting the first radio frequency signal, or the second analog signal is the first radio frequency signal.

16. The method according to claim 15, characterized in that, Before performing analog-to-digital conversion, the method further includes: Adjust the first power of the analog signal component in the first analog signal located in the interference frequency band and the second power of the analog signal component in the second analog signal located in the main frequency band so that the difference between the first power and the second power is less than a preset value.

17. The method according to any one of claims 14 to 16, characterized in that, The synthesis of the third predistorted signal based on the first predistorted signal and the second predistorted signal includes: A digital signal combiner is used to combine the first predistorted signal and the second predistorted signal into a predistorted baseband signal; The predistorted baseband signal is subjected to digital-to-analog conversion and up-conversion processing to obtain the third predistorted signal.

18. The method according to any one of claims 14 to 16, characterized in that, The synthesis of the third predistorted signal based on the first predistorted signal and the second predistorted signal includes: The first predistorted signal and the second predistorted signal are converted from digital to analog to obtain the third analog signal and the fourth analog signal, respectively. Noise located in the interference frequency band is filtered out from the third analog signal, and a noise-reduced third analog signal is output. The third and fourth analog signals, which have undergone noise reduction, are combined to obtain a predistorted analog signal. The predistorted analog signal is up-converted to obtain the third predistorted signal.

19. The method according to claim 18, characterized in that, Before the third and fourth analog signals based on the noise reduction are combined, the method further includes: Adjust the ratio between the power of the third analog signal and the power of the fourth analog signal for noise reduction.

20. The method according to any one of claims 14 to 16, characterized in that, The synthesis of the third predistorted signal based on the first predistorted signal and the second predistorted signal includes: The first predistorted signal and the second predistorted signal are converted from digital to analog to obtain the third analog signal and the fourth analog signal, respectively. Noise located in the interference frequency band is filtered out from the third analog signal, and a noise-reduced third analog signal is output. The third and fourth analog signals, which have undergone noise reduction, are up-converted to obtain the third and fourth radio frequency signals, respectively. The third predistortion signal is obtained by combining the third radio frequency signal and the fourth radio frequency signal.

21. The method according to claim 20, characterized in that, Before the merging process based on the third radio frequency signal and the fourth radio frequency signal, the method further includes: Adjust the ratio between the power of the third radio frequency signal and the power of the fourth radio frequency signal.

22. The method according to any one of claims 14 to 16, characterized in that, The step of performing predistortion processing on the second baseband signal based on the secondary distortion signal and the primary distortion signal respectively to obtain a first predistortion signal and a second predistortion signal includes: The first predistortion signal is generated based on the second baseband signal and the first predistortion model, wherein the first predistortion model is obtained by training using the auxiliary distortion signal and the first baseband signal; The second predistortion signal is generated based on the second baseband signal and the second predistortion model, wherein the second predistortion model is obtained by training using the main distortion signal and the first baseband signal.

23. The method according to any one of claims 14 to 16, characterized in that, The frequency value of the main frequency band is greater than the frequency value of the interference frequency band.

24. The method according to any one of claims 14 to 16, characterized in that, The main frequency band is a wireless communication frequency band, and the interference frequency band is a satellite frequency band.

25. A launching system, characterized in that, include: The radio frequency amplifier and the frequency predistortion device as described in any one of claims 1 to 13.

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