WO2023015461A1

WO2023015461A1 - Base station, central station, and nonlinear signal processing method

Info

Publication number: WO2023015461A1
Application number: PCT/CN2021/111907
Authority: WO
Inventors: 李建平; 郭少南; 胡克彬; 黄丹; 于香起
Original assignee: 华为技术有限公司
Priority date: 2021-08-10
Filing date: 2021-08-10
Publication date: 2023-02-16
Also published as: CN117941291A

Abstract

The present application discloses a base station, a central station, and a nonlinear signal processing method. The base station comprises multiple radio frequency links, an optical module, and a feature calculation module; the optical module is used to execute electro-optical conversion on signals of the multiple radio frequency links, send obtained optical signals to the central station, and execute photoelectric conversion on the optical signals to obtain electrical signals; the multiple radio frequency links comprise a first radio frequency link and at least one second radio frequency link, the optical module contains a nonlinear component, a signal of the at least one second radio frequency link passes through the nonlinear component and then generates a nonlinear distortion signal that overlaps with a corresponding frequency band of the first radio frequency link, and the optical signal contains the nonlinear distortion signal; the feature calculation module is used to extract a target signal of the corresponding frequency band of the first radio frequency link from the electrical signals, and calculate a nonlinear distortion prediction signal according to the target signal and the signal of the at least one second radio frequency link; and the first radio frequency link is used to execute pre-distortion processing on the signal of the corresponding frequency band according to the nonlinear distortion prediction signal.

Description

A base station, central station and nonlinear signal processing method

technical field

The present application relates to the technical field of communication, and in particular to a base station, a central station and a nonlinear signal processing method.

Background technique

There are many nonlinear components on the wireless communication link in the wireless communication system, such as low-noise amplifier, power amplifier (Power Amplifier, PA), photoelectric conversion (Optical-Electro, O/E) components, electro-optical conversion (Electro- Optical, E/O) components, etc. These nonlinear components may cause nonlinear distortion of the signal on the communication link. Specifically, the output signal of the nonlinear component will appear in the output signal of a new frequency that is not in the input signal. The component signal is a nonlinear distortion signal, which will interfere with the subsequent processing of some normal signals and affect the performance of the wireless communication system.

At present, in order to solve the nonlinear distortion problem on the communication link in the wireless communication system, the nonlinear characteristics of the nonlinear components in the system can be corrected by analog predistortion to reduce the nonlinear distortion caused by the nonlinear components. Influence. Analog predistortion refers to processing the signal input to the nonlinear components in advance, so that the signal change caused by the processing and the nonlinear distortion generated after the signal is input to the nonlinear components cancel each other, so that the nonlinear distortion caused by the nonlinear components Distortion is corrected. In the above method, the link for correcting the nonlinear index of nonlinear components is generally fixed, and the fitting ability of nonlinear distortion in the process of analog predistortion is limited, and can only be targeted to a certain extent Improve the characteristics of certain types of nonlinear components, so this method has a low ability to correct nonlinear distortion.

Contents of the invention

The application provides a base station, a central station, and a nonlinear signal processing method to improve the accuracy of calculating nonlinear distortion signals caused by nonlinear components, thereby further improving the correction of nonlinear distortion caused by nonlinear components or compensated performance.

In the first aspect, the present application provides a base station, including: a plurality of radio frequency links, an optical module, and a feature calculation module; wherein, the number of the plurality of radio frequency links is greater than or equal to 2; each radio frequency link is used for Receive one signal of the corresponding frequency band through the antenna, and send the one signal to the optical module after performing radio frequency processing on the one signal; The signal is subjected to electro-optical conversion processing to obtain an optical signal including the processed multi-channel signal; wherein, the optical module includes nonlinear components, and there are a first radio frequency link and at least one radio frequency link among the plurality of radio frequency links The second radio frequency link, the signal of the at least one second radio frequency link passes through the nonlinear component to generate a nonlinear distortion signal, and the frequency band of the nonlinear distortion signal corresponds to the frequency band of the first radio frequency link There is overlap, the optical signal also includes the nonlinear distortion signal; sending the optical signal to the central station, and performing photoelectric conversion processing on the optical signal to obtain an electrical signal, and sending the electrical signal to the The feature calculation module; each second radio frequency link is also used to perform radio frequency processing on the received signal of the corresponding frequency band, and then send the obtained signal to the feature calculation module; the feature calculation module is used for from Extracting a target signal from the electrical signal of the optical module; wherein, the target signal includes a signal of a frequency band corresponding to the first radio frequency link contained in the electrical signal; according to the target signal and the signal from the Calculate the nonlinear distortion prediction signal for at least one signal of the at least one second radio frequency link, and send the nonlinear distortion prediction signal to the first radio frequency link, where the nonlinear distortion prediction signal is the A first prediction signal of a nonlinear distortion signal; the first radio frequency link is further configured to perform predistortion processing and radio frequency processing on a signal in a frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, and Send the processed signal to the optical module.

In this solution, the base station can predict and calculate the nonlinear distortion signal generated when the subsequent signal passes through the nonlinear component based on the signal that has previously passed through the nonlinear component and the nonlinear distortion signal caused by the nonlinear component, which can improve The accuracy of the determined nonlinear distortion prediction signal can further predistort the signal transmitted on the transmission link according to the determined nonlinear distortion prediction signal, so as to realize the detection of the signal generated when the signal on the transmission link passes through nonlinear components The correction of nonlinear distortion problem improves the accuracy of nonlinear distortion correction.

In a possible design, the start frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency, wherein: when the multiple radio frequency chains When there is a second radio frequency link in the road, the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, and the second frequency is the frequency corresponding to the second radio frequency link. Twice the cutoff frequency of the frequency band; or, when there are two second radio frequency links in the plurality of radio frequency links, the first frequency is the start frequency of the frequency band corresponding to the two second radio frequency links sum, the second frequency is the sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the start frequency of the frequency bands corresponding to the two second radio frequency links The second frequency is the difference between the cutoff frequencies of the corresponding frequency bands of the two second radio frequency links.

In a possible design, the feature calculation module includes an iterative calculation module, and the iterative calculation module is used to: calculate a target parameter according to the target signal, wherein the target parameter is used to characterize the nonlinear component nonlinear distortion characteristics; calculate the target prediction signal according to at least one signal of the at least one second radio frequency link, wherein the target prediction signal is the second prediction signal of the nonlinear distortion signal; according to the target parameter The target prediction signal is corrected to obtain the nonlinear distortion prediction signal.

In this scheme, the base station calculates the nonlinear distortion characteristic parameters of the nonlinear components based on the signal actually passing through the nonlinear components and the nonlinear distortion signal actually generated after the signal passes through the nonlinear components, which can improve the determination of nonlinear components. The accuracy of the nonlinear distortion characteristics of the device is improved, thereby improving the accuracy of correcting the target prediction signal based on the nonlinear distortion characteristic parameters of the nonlinear components.

In a possible design, the iterative calculation module, when calculating the target parameter according to the target signal, is specifically configured to: calculate the target parameter according to the set first calculation model and the target signal, wherein , the first calculation model is used to represent one of the multiple signals input to the nonlinear component, the nonlinear distortion signal output by the nonlinear component and the same frequency band as the one signal and the nonlinear The correspondence between the nonlinear distortion characteristic parameters of components; when the iterative calculation module calculates the target prediction signal according to at least one signal of the at least one second radio frequency link, it is specifically used for: according to the set second calculation model and at least one signal of the at least one second radio frequency link, and calculate the target prediction signal, wherein the second calculation model is used to represent the at least one signal passing through the nonlinear component and the at least one signal passing through Correspondence between nonlinear distortion signals generated by the nonlinear components.

In this scheme, the base station predicts the nonlinear distortion signal generated by the useful signal through the nonlinear components by using the useful signal and the distorted signal for modeling calculation, and can obtain the required calculation simply, quickly and accurately through the calculation model target prediction signal.

In a possible design, when the iterative calculation module corrects the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal, it is specifically configured to: combine the target parameter with the The target prediction signal is multiplied to obtain the nonlinear distortion prediction signal.

In this scheme, the base station can further improve the accuracy of the determined nonlinear distortion prediction signal by correcting the predicted nonlinear distortion signal according to the nonlinear distortion characteristic parameters of the nonlinear components.

In a possible design, the optical module includes: an electro-optical conversion module, a photoelectric conversion module, a first port, a second port, and a third port; Conversion processing, the electro-optical conversion module includes the nonlinear components; the photoelectric conversion module is used to perform photoelectric conversion processing on the optical signal; the first port is used to receive the multi-channel signal; The second port is used to send the optical signal to the central station; the third port is used to send the electrical signal to the feature calculation module.

In this scheme, by improving the structure of the optical module in the base station and adding a signal transmission port and a photoelectric conversion module, the electrical signal corresponding to the optical signal sent by the base station to the central station can be obtained, so that useful signals can be obtained from the electrical signal The nonlinear distortion signal generated after passing through the nonlinear components of the optical module is fed back to the digital link of the base station, which is convenient for modeling and pre-distortion correction of nonlinear components.

In a possible design, the feature calculation module further includes a filtering module; the filtering module is configured to filter the electrical signal to obtain the target signal.

In this scheme, the base station performs filtering processing on the signal through the filtering module, which can only retain the required signal, avoid some unnecessary signals from interfering with the subsequent processing process, and thus improve the accuracy of signal processing.

In a possible design, the feature calculation module further includes a feedback module, configured to: perform delay correction processing on the target signal and at least one signal of the at least one second radio frequency link, Obtain the target signal and at least one signal of the at least one second radio frequency link with consistent time delays.

In this solution, the base station can ensure that the non-linear distortion prediction signal determined according to the target signal and the at least one second radio frequency link signal have a time delay correction process on the target signal and at least one second radio frequency link signal are corresponding, so as to avoid errors caused by delay problems in the signal processing process.

In a possible design, the feedback module includes: a lock module, a correlator, a threshold judgment module, a time delay calculation module, and a time delay alignment module; A signal of the set time slot length of the second radio frequency link, and the latched signal is sent to the correlator; the correlator is used to perform the target signal and the signal from the lock module Correlation processing, obtaining a correlation signal, and sending the correlation signal to the threshold judgment module, wherein the correlation signal is a nonlinear signal; the threshold judgment module is used to judge the correlation of the received correlation signal Whether the value is greater than or equal to the set value, if so, then the relevant signal is sent to the time delay calculation module, otherwise, the relevant signal is not processed; the time delay calculation module is used to When the correlation signal of the threshold judgment module is used, the time delay between the signal of the first radio frequency link and the signal of the set time slot length of the at least one second radio frequency link is calculated according to the correlation signal, and sending the time delay to the time delay alignment module; the time delay alignment module is configured to remove the time delay according to the time delay after receiving the time delay from the time delay calculation module In the target signal, there is the time-delayed signal with the signal of the set time slot length of the at least one second radio frequency link, and removing the time delay between the signal of the set time slot length of each second radio frequency link and The target signal has the time-delayed signal.

In this solution, the base station can determine the time delay existing between the target signal and the signal of the at least one second radio frequency link through time delay calculation, and then calculate the time delay between the target signal and the at least one second radio frequency link according to the time delay The time delay of the link signal is corrected, and at the same time, the timing update of the time delay calculation process is controlled by the lock number control method, which reduces a certain amount of signal processing.

In a possible design, the threshold decision module is further configured to: when it is determined that the correlation value of the correlation signal is greater than or equal to the set value, instruct the lock module to respectively latch the A signal of a set time slot length of the second radio frequency link, and use the currently locked signal to replace the previously latched signal; when it is determined that the correlation value of the related signal is less than the set value, indicate the The locking module stops locking the signal of the set time slot length from the at least one second radio frequency link.

In this scheme, the threshold decision module of the base station controls the triggering of the lock module according to the magnitude of the correlation value of the nonlinear distortion signal and the correlation signal corresponding to the signal of at least one second radio frequency link, which can be based on the actual scene The actual signal situation controls the update situation of the lock number to improve the accuracy of related control and scene adaptability.

In a possible design, when the first radio frequency link performs predistortion processing on the signal in the frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, it is specifically used to: The nonlinear distortion prediction signal is subtracted from the signal in the frequency band corresponding to the radio frequency link to obtain a signal after predistortion processing is performed on the signal in the frequency band corresponding to the first radio frequency link.

In a second aspect, the present application provides a base station, including: a plurality of radio frequency links, an optical module, and a feature calculation module; wherein, the number of the plurality of radio frequency links is greater than or equal to 2; each radio frequency link is used for Receive one signal of the corresponding frequency band through the antenna, and send the one signal to the optical module after performing radio frequency processing on the one signal; The signal is subjected to electro-optical conversion processing to obtain an optical signal including the processed multi-channel signal; wherein, the optical module includes nonlinear components, and there are a first radio frequency link and at least one radio frequency link among the plurality of radio frequency links The second radio frequency link, the signal of the at least one second radio frequency link passes through the nonlinear component to generate a nonlinear distortion signal, and the frequency band of the nonlinear distortion signal corresponds to the frequency band of the first radio frequency link There is overlap, and the optical signal also includes the nonlinear distortion signal; sending the optical signal to the central station, receiving the target signal from the central station, and performing photoelectric conversion processing on the target signal, and sending the processed target signal to the feature calculation module, wherein the target signal includes a signal of a frequency band corresponding to the first radio frequency link; each second radio frequency link is also used for receiving After performing radio frequency processing on one signal in the corresponding frequency band, the obtained signal is sent to the feature calculation module; the feature calculation module is used to receive the target signal from the optical module; according to the target signal and the At least one signal of the at least one second radio frequency link calculates a nonlinear distortion prediction signal, and sends the nonlinear distortion prediction signal to the first radio frequency link, where the nonlinear distortion prediction signal is the The first prediction signal of the nonlinear distortion signal; the first radio frequency link is also used to perform pre-distortion processing and radio frequency processing on the signal of the frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, And send the processed signal to the optical module.

In this scheme, the base station sends the signal after passing through the nonlinear components to the central station, and then receives the signal containing the useful signal and the nonlinear distortion signal caused by the nonlinear component that is looped back by the central station, which can be based on the previous The signal of the nonlinear component and the nonlinear distortion signal caused by the nonlinear component can predict and calculate the nonlinear distortion signal generated when the subsequent signal passes through the nonlinear component, which can improve the accuracy of the determined nonlinear distortion prediction signal , and further, the signal transmitted on the transmission link can be pre-distorted according to the determined nonlinear distortion prediction signal, so as to realize the correction of the nonlinear distortion problem generated when the signal on the transmission link passes through nonlinear components, and improve the performance of nonlinear distortion. Accuracy of linear distortion correction.

In a possible design, when the optical module receives the target signal from the central station, performs photoelectric conversion processing on the target signal, and sends the processed target signal to the feature calculation module, Specifically used for: receiving a downlink signal from the central station, performing photoelectric conversion processing on the downlink signal, and sending the processed downlink signal to the feature calculation module, wherein the downlink signal includes the The target signal and other signals to be sent to the base station; when the feature calculation module receives the target signal from the optical module, it is specifically used to: receive the downlink signal from the optical module, and The downlink signal is filtered to obtain the target signal.

In this scheme, the base station can extract the target signal from the signal from the central station, which facilitates subsequent processing of the target signal, and avoids interference from other signals on the processing process of the target signal, thereby improving the accuracy of signal processing. At the same time, the target signal is looped back through the central station, so the nonlinear distortion problems of some related nonlinear components in the central station can also be corrected to a certain extent.

In a third aspect, the present application provides a central station, including: an optical module and a signal processing module; the optical module is used to perform photoelectric conversion processing on the optical signal to obtain an electrical signal after receiving an optical signal from a base station, and send the optical signal to the The signal processing module sends the electrical signal; wherein, the electrical signal includes nonlinear distortion signals, multiple signals received by the multiple radio frequency links of the base station through antennas, and the multiple radio frequency links of the multiple radio frequency links The number is greater than or equal to 2, there are a first radio frequency link and at least one second radio frequency link in the plurality of radio frequency links, the base station contains nonlinear components, and the signal of the at least one second radio frequency link The nonlinear distortion signal is generated after passing through the nonlinear components, and the frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link; the signal processing module is used to receive signals from the The electrical signal of the optical module, extracting the target signal of the frequency band corresponding to the first radio frequency link from the electrical signal, and sending the target signal to the optical module; the optical module also uses performing electro-optical conversion processing on the target signal, and sending the processed target signal to the base station.

In this scheme, the central station and the base station can form a loopback link, and the central station loops back the signal from the base station to the base station, so that the base station can correct the nonlinear distortion generated when the subsequent signal passes through the nonlinear components based on the actual signal The signal is predicted and calculated, and the signal transmitted on the transmission link is pre-distorted according to the predicted nonlinear distortion signal, so as to improve the accuracy of the nonlinear distortion correction of the communication link between the base station and the central station. While correcting the nonlinear distortion problem in the base station, it can also correct some nonlinear distortion problems in the central station, and improve the accuracy of communication between the central station and the base station.

In a possible design, the signal processing module includes a filtering module, and the filtering module is configured to receive the electrical signal from the optical module, filter the electrical signal, and obtain the target signal; When the optical module performs electro-optical conversion processing on the target signal, and sends the processed target signal to the base station, it is specifically used to: perform the target signal and other signals to be sent to the base station Electro-optical conversion processing, obtaining a downlink signal including the target signal and other signals to be sent to the base station, and sending the downlink signal to the base station.

In this scheme, the central station filters the signal through the filtering module, which can only retain the required signal, avoid some unnecessary signals from interfering with the subsequent processing process, and improve the accuracy of signal processing. The central station can send the target signal and other signals to the base station in one wave, which can make full use of the existing transmission link, avoid the overhead of adding an additional transmission link, and improve resource utilization.

In a fourth aspect, the present application provides a central station, including: an optical module, a signal processing module, and a feature calculation module; the optical module is configured to receive an optical signal from at least one base station, and perform an operation on each of the at least one base station The optical signal of the base station is subjected to photoelectric conversion processing to obtain the electrical signal of each base station; wherein, the electrical signal of any base station includes a nonlinear distortion signal, and multiple signals received by multiple radio frequency links of the base station through the antenna, The number of the plurality of radio frequency links is greater than or equal to 2, there are a first radio frequency link and at least one second radio frequency link in the plurality of radio frequency links, the base station contains nonlinear components, and the at least A signal of a second radio frequency link passes through the nonlinear component to generate the nonlinear distortion signal, and the frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link; The electrical signals of the base stations are sent to the signal processing module and the feature calculation module; the feature calculation module is used to receive the electrical signals from each base station of the optical module respectively; respectively for the electrical signals of each base station Perform feature calculation processing to obtain the nonlinear distortion prediction signal corresponding to each base station, and send the nonlinear distortion prediction signal corresponding to each base station to the signal processing module; wherein, the characteristic of the electrical signal of any one base station The calculation processing includes the following steps: extracting the target signal of the frequency band corresponding to the first radio frequency link from the electrical signal, and respectively extracting at least one channel from the at least one second radio frequency link from the electrical signal signal; calculate the nonlinear distortion prediction signal according to the target signal and at least one signal of the at least one second radio frequency link, wherein the nonlinear distortion prediction signal is the first prediction of the nonlinear distortion signal signal; the signal processing module is configured to respectively receive electrical signals from each base station of the optical module; perform combined processing on the electrical signals of the at least one base station to obtain a target combined signal; respectively receive signals from the features The nonlinear distortion prediction signal corresponding to each base station of the calculation module; sequentially perform distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to each base station.

In this solution, when the central station processes the signal from at least one base station, it can process the subsequent signal through the non-linear component based on the signal that has previously passed through the nonlinear component in the base station and the nonlinear distortion signal caused by the nonlinear component. Prediction and calculation of the nonlinear distortion signal generated by the linear components can improve the accuracy of the determined nonlinear distortion prediction signal, and furthermore, the signal transmitted from at least one base station can be more accurately calculated according to the determined nonlinear distortion prediction signal Distortion correction processing. At the same time, in this scheme, the central station can perform distortion correction processing on the signals from different base stations, and can effectively correct the nonlinear distortion problem of the base station and the central station.

In a possible design, the feature calculation module includes an iterative calculation module, and the iterative calculation module is used to: calculate a target parameter according to the target signal, wherein the target parameter is used to characterize the nonlinear component The nonlinear distortion characteristic; calculate the target prediction signal according to at least one signal from the at least one second radio frequency link, wherein, the target prediction signal is the second prediction signal of the nonlinear distortion signal; according to the target parameters to modify the target prediction signal to obtain the nonlinear distortion prediction signal.

In this scheme, the central station calculates the nonlinear distortion characteristic parameters of the nonlinear components based on the signal actually passing through the nonlinear components and the nonlinear distortion signal actually generated after the signal passes through the nonlinear components, which can improve the determination of nonlinear The accuracy of the nonlinear distortion characteristic of the component is improved, and then the accuracy of correcting the target prediction signal based on the nonlinear distortion characteristic parameter of the nonlinear component is improved.

In this scheme, the central station predicts the nonlinear distortion signal generated by the useful signal through the nonlinear components by using the useful signal and the distorted signal for modeling calculation, and can obtain the required information easily, quickly and accurately through the calculation model. Calculated target prediction signal.

In this solution, the central station can further improve the accuracy of the determined nonlinear distortion prediction signal by correcting the predicted nonlinear distortion signal according to the nonlinear distortion characteristic parameters of the nonlinear components.

In a possible design, the feature calculation module further includes a filtering module; the filtering module is configured to filter the combined electrical signal to obtain the target signal.

In this scheme, the central station filters the signal through the filtering module, which can only retain the required signal, avoid some unnecessary signals from interfering with the subsequent processing process, and improve the accuracy of signal processing.

In this solution, the central station can ensure that the non-linear distortion prediction signal determined according to the target signal and the at least one second radio frequency link signal are within a time delay correction process for the target signal and at least one second radio frequency link signal The above is corresponding, so as to avoid the error caused by the delay problem in the signal processing process.

In this scheme, the central station can determine the time delay existing between the target signal and the signal of the at least one second radio frequency link through time delay calculation, and then calculate the time delay between the target signal and the at least one second radio frequency link according to the time delay. The delay is corrected for the signal of the radio frequency link, and at the same time, the timing update of the delay calculation process is controlled by the lock number control method, which reduces a certain amount of signal processing.

In this scheme, the threshold decision module of the central station controls the triggering of the lock module according to the magnitude of the correlation value of the nonlinear distortion signal and the correlation signal corresponding to the signal of at least one second radio frequency link, which can be based on the actual scene According to the actual signal situation, the update situation of the number of locks is controlled, and the accuracy of related control and scene adaptability are improved.

In a possible design, the at least one base station includes a first base station and a second base station, and the signal processing module sequentially processes the target combined signal according to the nonlinear distortion prediction signal corresponding to each base station. During the distortion correction processing, it is specifically used to: perform distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to the first base station to obtain the first target combined signal; The nonlinear distortion prediction signal performs distortion correction processing on the first target combined signal to obtain a second target combined signal.

In a possible design, when the signal processing module performs distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to the first base station to obtain the first target combined signal, specifically It is used for: subtracting the nonlinear distortion prediction signal corresponding to the first base station from the target combined signal to obtain the first target combined signal.

In a fifth aspect, the present application provides a nonlinear signal processing method, which is applied to a base station or a central station. The method includes: calculating target parameters according to the target signal, wherein the target signal includes: a first signal, at least one second signal is a nonlinear distortion signal generated after passing through a nonlinear component, the frequency band of the nonlinear distortion signal overlaps with the frequency band of the first signal, and the target parameter is used to characterize the nonlinear distortion signal Non-linear distortion characteristics of linear components; calculating a target prediction signal according to the at least one second signal, wherein the target prediction signal is a prediction signal of the nonlinear distortion signal; predicting the target according to the target parameter The signal is corrected to obtain a nonlinear distortion prediction signal; wherein, the nonlinear distortion prediction signal is a modified prediction signal of the nonlinear distortion signal.

In a possible design, calculating the target parameter according to the target signal includes: calculating the target parameter according to the set first calculation model and the target signal, wherein the first calculation model is used to represent the input non- Correspondence between one signal among the multiple signals of the linear component, the nonlinear distortion signal output by the nonlinear component with the same frequency band as the one signal, and the nonlinear distortion characteristic parameters of the nonlinear component relation.

In a possible design, calculating the target prediction signal according to the at least one second signal includes: calculating the target prediction signal according to a set second calculation model and the at least one second signal, wherein the The second calculation model is used to represent the corresponding relationship between at least one signal passing through the nonlinear component and the nonlinear distortion signal generated after the at least one signal passes through the nonlinear component.

In a possible design, correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal includes: multiplying the target parameter by the target prediction signal to obtain the Nonlinear distortion prediction signal.

In a sixth aspect, the present application provides a device, the device includes a memory and a processor; the memory is used to store computer programs; the processor is used to execute the computer programs stored in the memory, to achieve the fifth aspect or Any possible design of the fifth aspect describes the method.

In a seventh aspect, the present application provides a communication system, the communication system comprising: the base station described in the above first aspect or any possible design of the first aspect, or the above second aspect or any possible design of the second aspect The base station described in the design, and the central station described in the third aspect or any possible design of the third aspect, or the central station described in the fourth aspect or any possible design of the fourth aspect.

For the above-mentioned beneficial effects of the second aspect, please refer to the description of the relevant beneficial effects of the above-mentioned first aspect, and for the above-mentioned beneficial effects of the fifth to seventh aspects, please refer to the description of the above-mentioned beneficial effects of the first to fourth aspects. Repeat it again.

Description of drawings

FIG. 1 is a schematic diagram of the architecture of an ROF system;

Fig. 2 is a schematic diagram of radio frequency signal transmission in an ROF system;

Fig. 3 is the example diagram of three kinds of scenes that produce IMD2 in ROF system;

Fig. 4a is a structural schematic diagram of an analog predistortion nonlinear correction link;

Fig. 4b is a structural schematic diagram of a nonlinear distortion correction link based on a push-pull structure joint adaptive post-compensation;

FIG. 5 is a schematic structural diagram of an ROF system provided in an embodiment of the present application;

FIG. 6 is a schematic diagram of a base station provided in an embodiment of the present application;

FIG. 7 is a schematic diagram of a feedback module in a base station provided by an embodiment of the present application;

FIG. 8 is a schematic diagram of an ROF system provided in an embodiment of the present application;

FIG. 9 is a schematic diagram of an ROF system provided by an embodiment of the present application;

FIG. 10 is a comparative schematic diagram of an optical module structure provided by an embodiment of the present application;

FIG. 11 is a simplified structural schematic diagram of a base station structure provided by an embodiment of the present application;

FIG. 12 is a schematic diagram of a base station and a central station provided in an embodiment of the present application;

FIG. 13 is a schematic diagram of an ROF system provided by an embodiment of the present application;

FIG. 14 is a schematic diagram of a central station provided by an embodiment of the present application;

FIG. 15 is a schematic diagram of an ROF system provided by an embodiment of the present application;

FIG. 16 is a schematic diagram of a nonlinear signal processing method provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions, and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings. Among them, in the description of the embodiments of the present application, the terms "first" and "second" are used for description purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features . Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features.

In order to facilitate understanding, descriptions of concepts related to the present application are provided as examples for reference.

1) Nonlinear distortion, which means that the output signal of a component (or electronic component) does not have a linear relationship with the input signal, which is caused by the nonlinear characteristics of the component. Nonlinear distortion is manifested as multiple signals of the same or different frequencies passing through nonlinear components (such as laser diodes, photodiodes, amplifiers, etc.), generating new harmonic components or interference signals of new frequency components.

Nonlinear distortion includes harmonic distortion (harmonic distortion, HD), intermodulation distortion (intermodulation distortion, IMD), and intermodulation distortion. Wherein, the intermodulation distortion is the distortion of the sum of the frequency components or the difference of the frequency components of an input signal introduced by the nonlinear components. When the signal enters the nonlinear components, the nonlinear characteristics of the nonlinear components will cause the mutual (modulation) effect between the signals, and generate additional signals that are not in the original signal. This additional signal may affect the original signal. Some signals are causing interference.

In the embodiment of the present application, the nonlinear components include, but are not limited to, an optoelectronic converter (electronic-optical converter, O-E), an electro-optical converter, an amplifier, and the like. Exemplarily, the photoelectric converter can be a photodiode (photo-diode, PD); the electro-optical converter can be a laser diode (laser diode, LD), and the amplifier can be a low noise amplifier (low noise amplifier, LNA).

2) Pre-distortion means that before the signal passes through the nonlinear components, the signal is subjected to a preprocessing process whose characteristics are opposite to the nonlinear distortion characteristics caused by the nonlinear components, so that it is different from the non-linear distortion generated when the signal passes through the nonlinear components. The linear distortion compensates each other, so as to reduce or avoid the nonlinear distortion caused by the nonlinear components.

It should be understood that "at least one" in the embodiments of the present application refers to one or more, and "multiple" refers to two or more. "And/or" describes the association relationship of associated objects, indicating that there may be three types of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone, where A, B can be singular or plural. The character "/" generally indicates that the contextual objects are an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural item(s). For example, at least one item (unit) of a, b or c can represent: a, b, c, a and b, a and c, b and c, or a, b and c, wherein a, b, c Can be single or multiple.

Currently, with the promotion of the 5th-generation wireless communication (5G) technology and the research of the 6th-generation wireless communication (6G) technology, the mobile network urgently needs to support ultra-large-scale wireless Technology for access and ultra-high-speed data transmission. ROF (radio over fiber, wireless communication over optical) technology was developed in response to the demand for high-speed and large-capacity wireless communication.

ROF is a wireless access technology that combines optical fiber communication and wireless communication. The ROF system generally includes a center station (center station, CS) and a base station (base station, BS), which communicate through optical fibers. Among them, the central station/base station can modulate the radio frequency electrical signal into an optical signal and then transmit the signal to the opposite end, and can realize the simultaneous ultra-wideband transmission of wireless carrier signals in multiple frequency bands by means of carrier multiplexing, which helps to reduce communication costs. System cost, power consumption and complexity etc. ROF is widely used in mobile wireless communication systems, cable television (CATV) systems, and satellite communication systems.

Fig. 1 shows a schematic diagram of the architecture of an ROF system. As shown in FIG. 1 , the ROF system may include a central station, a base station, and may also include user equipment.

In the embodiment of the present application, the base station may also be called a head end, an analog head end, or a remote radio unit (remote radio unit, RRU). The central station may also be called a mother end, an analog mother end, or a baseband unit (BBU).

Referring to Figure 1, in the ROF system, taking the communication downlink process as an example, the central station can modulate the radio frequency electrical signal (also called electromagnetic wave/microwave) to the laser, and then the modulated light wave can be transmitted to the base station through an optical fiber link After the base station receives the light wave signal from the central station, it demodulates the light wave signal through photoelectric conversion to obtain an electrical signal, and then transmits it to the user equipment through the antenna for use by the user equipment. The communication downlink process is opposite to the above communication uplink process, and will not be repeated here.

In the ROF system, the optical carrier link such as optical fiber or optical hybrid cable is used as the transmission link between the central station and the base station, and the optical carrier can be directly used to transmit radio frequency signals, thereby reducing signal transmission loss. Among them, the above-mentioned optical link only plays the role of signal transmission, and the processing of signal exchange, control and signal regeneration can be concentrated in the central station, and the base station can realize the optical-electrical format conversion of the signal, so that complex and high-level The cost devices are concentrated in the central station, so that multiple base stations can share the resources of the central station, thereby reducing the power consumption and cost of the base station.

The advantages of ROF system in wireless communication mainly include the following points: ROF system uses optical transmission technology for signal transmission, which has lower transmission loss than electrical transmission technology (usually the fiber attenuation is less than 0.4dB/km); ROF system supports ultra- Broadband signal bearing and transmission capability (transmission frequency can reach 0-40GHz); ROF system is easy to install and maintain (the weight of optical fiber is about one tenth of that of coaxial cable, and the cost of optical fiber is low), and ROF system has strong confidentiality (transmission The signal is carried by optical fiber, which can resist electromagnetic interference and enhance safety and confidentiality).

While having obvious advantages, the ROF system also has some disadvantages. For example, the ROF system is an analog transmission system, so it is prone to signal impairments (such as noise and distortion); nonlinear effects such as dispersion may occur in optical links; electrical–optical (electrical–optical, E-O) and optical-electrical (O-E) conversion increase the complexity of processing and increase the deployment cost of the ROF system; some nonlinear components in the ROF system will cause nonlinear distortion of the signal and reduce the performance of the ROF system .

FIG. 2 is a schematic diagram of radio frequency (radio frequency, RF) signal transmission in an ROF system. As shown in Figure 2, in the radio frequency signal transmission of the ROF system, some nonlinear components such as laser diodes, photodiodes, radio frequency amplifiers, etc. can be used to implement functions such as signal processing and transmission. However, these nonlinear components may cause nonlinear distortion of the signal during signal processing and transmission, affecting the accurate processing of the signal, especially in the case of multiple users, which will seriously reduce the performance of the ROF system.

Common nonlinear distortion problems in ROF systems include harmonic distortion, intermodulation distortion, and intermodulation distortion. The following takes second-order intermodulation distortion (IMD2) as an example for a brief description. Wherein, IMD2 may be generated after signals of two different frequency bands pass through nonlinear components, or may be generated after signals of the same frequency band pass through nonlinear components. Fig. 3 is an example diagram of three scenarios in which IMD2 is generated in the ROF system.

Exemplarily, in the first possible scenario, such as scenario 1 shown in FIG. 3 , IMD2 is the distortion of the sum of signal frequency components in two frequency bands passing through the nonlinear component. For example, the center frequency of the signal S _F1 is F1, the signal frequency range of the signal S _F1 is the frequency band F11-F12, the center frequency of the signal S _F2 is F2, the signal frequency range of the signal S _F2 is the frequency band F21-F22, the signal S _F1 and The IMD2 signal may be generated after the signal S _F2 passes through the nonlinear components at the same time. The frequency range of the IMD2 signal is between (F11+F21)~(F12+F22). When the overlapping signal S _F3 , signal S _F1 , and signal S _F2 pass through the nonlinear components at the same time, the IMD2 signal generated after the signal S _F1 and the signal S _F2 pass through the nonlinear components will hit the signal S _F3 , causing damage to the signal S _F3 Interference affects subsequent normal processing of the signal S _F3 .

In the second possible scenario, such as scenario 2 shown in FIG. 3 , IMD2 is the distortion of the difference between the signal frequency components of the two frequency bands passing through the nonlinear component. For example, the frequency range of the IMD2 signal generated by the above-mentioned signal S _F1 and the signal S _F2 passing through the nonlinear components at the same time is between (F11-F21) ~ (F12-F22), and the frequency band of the IMD2 signal is the same as that of the above-mentioned signal S _F3 When the frequency bands overlap, they will also hit the signal S _F3 , causing interference to the signal S _F3 and affecting subsequent normal processing of the signal S _F3 .

In the third possible scenario, such as scenario 3 shown in FIG. 3 , IMD2 is the distortion of the sum of frequency components of signals in a frequency band passing through nonlinear components. For example, when the above-mentioned signal S _F1 is the same as the signal S _{F2, for example, only the signal S F1} _, the frequency range of the IMD2 signal generated by the signal S _F1 after passing through the nonlinear components is the frequency range 2F11-2F12, and the frequency range of the IMD2 signal is the same as the above-mentioned signal S When the frequency bands of _F3 overlap, they will also hit the signal S _F3 , causing interference to the signal S _F3 and affecting subsequent normal processing of the signal S _F3 .

The second-order intermodulation distortion signals in the above three scenarios will affect the normal processing of useful signals, thereby affecting the performance of the ROF system.

In order to solve the problem of nonlinear distortion caused by nonlinear components in the ROF system, one solution is to correct the nonlinear distortion in the ROF system through analog pre-distortion, and another solution is to combine the push-pull structure with the automatic The post-adaptive compensation method corrects the nonlinear distortion in the ROF system.

Fig. 4a is a schematic structural diagram of an analog predistortion nonlinear correction link. As shown in Figure 4a, in the scheme of correcting the nonlinear distortion in the ROF system by means of analog predistortion, multiple functional units from the nonlinear distortion signal generation unit to the second phase adjustment unit constitute an analog predistortion Correct the link. The analog predistortion correction link can be built by using pre-designed analog components with fixed parameters and component characteristics to realize the analog predistortion function, which can improve some nonlinear distortion problems to a certain extent. However, in this solution, since the pre-distortion correction link is generally fixed, it can only correct the nonlinear distortion caused by certain types of nonlinear components in a targeted manner, and cannot achieve self-adaptation for the nonlinear distortion caused by different nonlinear components. Iterative correction processing, the scope of use is relatively limited. At the same time, the fitting capability of the fixed analog pre-distortion correction link to the nonlinear distortion signal is relatively limited, resulting in limited correction performance of the analog pre-distortion correction link. In addition, the analog predistortion correction chain cannot adaptively fit the nonlinear effects caused by temperature changes.

Fig. 4b is a schematic structural diagram of a nonlinear distortion correction link based on a push-pull structure combined with adaptive post-compensation. As shown in Figure 4b, in the method of correcting the nonlinear distortion in the ROF system based on the push-pull structure joint adaptive post-compensation method, the phase difference between the uplink and downlink in the system is maintained at around 180 degrees through the push-pull structure , the receiver uses balanced detection to suppress all even-order nonlinear distortions, and then uses an adaptive compensation algorithm to suppress the main odd-order nonlinear distortions. The scheme can adaptively suppress the even-order distortion (such as second-order intermodulation distortion IMD2 and second-order harmonic distortion HD2) and odd-order distortion (such as third-order intermodulation distortion) generated by the nonlinearity of nonlinear components in the system simultaneously. IMD3, XMD3, etc.). However, two sets of LDs and PDs in the correction link of this solution need to be deployed, which has the problems of high system deployment cost and large deployment area of components.

The above solution for nonlinear distortion correction has problems such as low nonlinear distortion correction performance and high cost. In view of this, an embodiment of the present application provides a base station, a central station, and a nonlinear signal processing method to implement the deployment of a nonlinear distortion correction system at a lower deployment cost, and at the same time improve the accuracy of calculating the nonlinear distortion signal, thereby The performance of correcting or compensating the nonlinear distortion according to the determined nonlinear distortion signal is further improved.

In the following embodiments of the present application, taking the solution to the second-order intermodulation distortion problem of the ROF system as an example, the base station, the central station and the nonlinear signal processing method provided in the embodiments of the present application are introduced in detail.

It should be understood that the base station, central station and nonlinear signal processing method provided in the embodiments of the present application are not limited to be applied to the ROF system, and can also be applied to the ROF-based analog optical wireless communication network architecture, similar central stations and distributed base station unit groups In network architectures such as the communication network architecture of the network, the communication network architecture in which multiple analog heads connect to a small number of central stations through optical transmission media (such as optical fiber or optical hybrid cable) (such as the network architecture in which multiple analog heads connect to a central station), etc. . In addition, the base station, the central station, and the nonlinear signal processing method provided in the embodiments of the present application can also be applied to various other wireless communication systems, so as to solve the problem of nonlinear distortion caused by nonlinear components in the wireless communication system. The wireless communication system may be, for example, a long term evolution (long term evolution, LTE) system, a 2G, 3G, 4G, 5G communication system, or a next generation communication system (such as a 6G system). It should also be understood that the base station, central station, and nonlinear signal processing method provided in the embodiments of the present application are not limited to solving the second-order intermodulation distortion problem, and can also solve harmonic distortion (such as HD2), intermodulation distortion (such as IMD3) and other nonlinear distortion problems.

FIG. 5 is a schematic structural diagram of an ROF system provided by an embodiment of the present application. As shown in FIG. 5 , in the embodiment of the present application, the ROF system adopts a digital-analog hybrid architecture. In the ROF system, the base station is mainly composed of optical modules, digital links, analog links and other parts. These parts constitute the downlink transmit (transport, TX) link and uplink receive (receive, RX) link in the base station. The base station can send the signal from the user equipment to the central station through the uplink receive link, or through the downlink The transmit link sends the signal from the central station to the user equipment.

Among them, the optical module is mainly used to convert the radio frequency electrical signal into an optical signal and then send it to the central station, or receive the optical signal from the central station and convert it into a radio frequency electrical signal. The digital link part can be realized by way of field programmable gate array (field programmable gate array, FPGA) or application specific integrated circuit (application specific integrated circuit, ASIC) or digital signal processing (digital signal processor, DSP) circuit. The digital link part can realize functions such as digital filtering, channel selection, and digital processing. The analog link part includes at least components or modules such as amplifiers (such as power amplifiers (PA), LNA, etc.), and the analog link can be used for preliminary processing of the signal received by the base station and transmits the signal to the digital link. way for further processing. What needs to be explained here is that in Figure 5, the digital link part is implemented as a DSP, and the analog link part includes PA or LNA as an example, but the structure or implementation of the digital link or analog link is not limited to Figure 5 in the manner indicated.

The central station mainly includes optical modules, signal processing modules, etc. Among them, the optical module is mainly used to convert the radio frequency electrical signal into an optical signal and then send it to the base station, or receive the optical signal from the base station and convert it into a radio frequency electrical signal. The signal processing module is mainly used to implement conversion processing among baseband (baseband, BB) signals, intermediate frequency (intermediate frequency, IF) signals, and radio frequency (radio frequency) signals.

The base station and the central station may be connected through an optical transmission medium, wherein the optical transmission medium may be an optical fiber, a photoelectric hybrid cable, or the like.

In the above-mentioned ROF system, the base station is a head-end architecture with a digital-analog hybrid design. Compared with the conventional head-end architecture with a purely analog design, it has greater flexibility in function design and has unique advantages in performance, especially for non-standard systems. The problem of linear correction will be described in detail below in conjunction with specific embodiments.

Embodiment one

FIG. 6 is a schematic diagram of a base station provided by an embodiment of the present application. As shown in FIG. 6, in this embodiment, the base station may include multiple radio frequency links (such as radio frequency link 1, radio frequency link 2, and radio frequency link 3 shown in FIG. 6), optical modules, and feature A computing module; wherein, the number of the plurality of radio frequency links is greater than or equal to two.

It should be noted that, for the convenience of introduction, only the case where the base station includes 3 radio frequency links is illustrated in FIG. 6 , and there may be more or less radio frequency links in the actual base station, which will not be repeated here.

In the base station, each radio frequency link is used to receive one signal of a corresponding frequency band through the antenna, and transmit the one signal to the optical module after performing radio frequency processing on the one signal. Wherein, any one or more signals may be signals from one user equipment, and signals of different channels may be signals from different user equipments.

The optical module is configured to perform electro-optical conversion processing on the multi-channel signals from the plurality of radio frequency links to obtain an optical signal including the processed multi-channel signals, and send the optical signal to the central station, and Performing photoelectric conversion processing on the optical signal to obtain an electrical signal and sending the electrical signal to the feature calculation module; wherein, there are a first radio frequency link and at least one second radio frequency link among the plurality of radio frequency links , the optical module includes a nonlinear component, and the signal of the at least one second radio frequency link passes through the nonlinear component to generate a nonlinear distortion signal, and the frequency band of the nonlinear distortion signal is the same as that of the first The frequency bands corresponding to the radio frequency links overlap; the optical signal includes the nonlinear distortion signal and the multichannel signal.

Optionally, the base station further includes a combiner module (not shown in FIG. 6 ), the combiner module is configured to receive multiple signals from the multiple radio frequency links, and combine the multiple signals Perform combination processing to obtain a combination signal, and send the combination signal to the optical module. The optical module is used to receive the combined signal from the combined module, and perform electro-optical conversion processing on the combined signal to obtain the optical signal. Exemplarily, the combining module may be a combiner.

Each second radio frequency link is further configured to perform radio frequency processing on a received signal of a corresponding frequency band, and then send the obtained signal to the feature calculation module.

The feature calculation module is configured to extract a target signal from the electrical signal from the optical module, wherein the target signal is a signal of a frequency band corresponding to the first radio frequency link included in the electrical signal ; calculate a nonlinear distortion prediction signal according to the target signal and at least one signal from the at least one second radio frequency link, and send the nonlinear distortion prediction signal to the first radio frequency link, wherein the The nonlinear distortion prediction signal is a first prediction signal of the nonlinear distortion signal.

The first radio frequency link is further configured to perform predistortion processing and radio frequency processing on signals in the frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, and send the processed signal to the optical module .

In some embodiments of the present application, the radio frequency processing performed by the radio frequency link may include one or more of filtering, power or energy amplification, frequency conversion, analog-to-digital conversion, transmission rate adjustment, power adjustment, and digital-to-analog conversion.

In some embodiments of the present application, the frequency band corresponding to the first radio frequency link overlaps with the frequency band of the nonlinear distortion signal, the starting frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the The cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency. Wherein, in a possible situation, there is a second radio frequency link in the plurality of radio frequency links, then the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link , the second frequency is twice the cutoff frequency of the frequency band corresponding to the one second radio frequency link; for example, the scenario 3 shown in FIG. 3 . In another possible situation, if there are two second radio frequency links among the plurality of radio frequency links, the first frequency is the sum of the starting frequencies of the corresponding frequency bands of the two second radio frequency links , the second frequency is the sum of the cut-off frequencies of the corresponding frequency bands of the two second radio frequency links, for example, the case of scenario 1 as shown in FIG. 3 ; or, the first frequency is the sum of the two second radio frequency links The difference between the start frequencies of the frequency bands corresponding to the two radio frequency links, and the second frequency is the difference between the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links, for example, the scenario 2 shown in FIG. 3 .

Exemplarily, when there is a second radio frequency link among the plurality of radio frequency links, the first radio frequency link may be the radio frequency link 3 shown in FIG. 6 , and the second radio frequency link may be It is radio frequency link 1 or radio frequency link 2 shown in FIG. The frequency band of the linear distortion signal overlaps with the frequency band of the signal on the radio frequency link 3 . When there are two second radio frequency links in the plurality of radio frequency links, the first radio frequency link may be the radio frequency chain 3 shown in FIG. 6, and the two second radio frequency links may be respectively shown in FIG. The radio frequency link 1 and the radio frequency link 2 shown in 6, the signals on the radio frequency link 1 and the radio frequency link 2 generate a nonlinear distortion signal after passing through the nonlinear components, and the nonlinear distortion The frequency band of the signal overlaps with the frequency band of the signal on the radio frequency link 3 .

In this embodiment, the optical module may include an electro-optic conversion module, a photoelectric conversion module, a first port, a second port, and a third port.

In the optical module, the first port is used to receive the multiple signals from the multiple radio frequency links and transmit them to the electro-optic conversion module.

The electro-optic conversion module is connected to the first port, and is used to perform electro-optical conversion processing on the multi-channel signal to obtain an optical signal, the electro-optic conversion module includes the nonlinear component, and the nonlinear component It can be used for electrical-optical conversion processing of signals. Exemplarily, the nonlinear component is an electro-optical converter, such as an LD.

Optionally, when the base station includes the combining module, the first port is connected to the combining module, and the first port is used to receive the combining module from the combining module. signal and transmit it to the electro-optical conversion module. The electro-optical conversion module is used to perform electro-optical conversion processing on the combined signal to obtain the optical signal.

The second port is connected to the electro-optical conversion module, and is used to send the optical signal obtained by the electro-optical conversion module, for example, to send the optical signal to a central station through an optical transmission medium.

The photoelectric conversion module is configured to receive the optical signal from the electro-optical conversion module, and perform photoelectric conversion processing on the optical signal to obtain the electrical signal. Exemplarily, the photoelectric conversion module is a photoelectric converter, such as a PD.

In some embodiments of the present application, the optical signal received by the photoelectric conversion module from the electro-optic conversion module may be obtained by sampling an optical signal obtained by performing electro-optic conversion processing by the electro-optic conversion module.

The third port is connected to the photoelectric conversion module, and is used to send the electrical signal obtained by the photoelectric conversion module to the feature calculation module.

In this embodiment, the feature calculation module includes a filter module and an iterative calculation module.

In the feature calculation module, the filtering module is configured to receive the electrical signal sent by the photoelectric conversion module through the third port, and filter the electrical signal to obtain the target signal. Exemplarily, the filtering module is a filter.

In some embodiments of the present application, when the filtering module performs filtering processing on the electrical signal, it may use the signal frequency band of the first radio frequency link as a reference to perform filtering, so as to filter out the electrical signal that is related to the electrical signal. A signal in a frequency band different from the signal frequency band of the first radio frequency link.

Optionally, the feature calculation module may further include a power amplification module, which is connected after the filter and used to amplify the power or energy of the target signal obtained by the filter. Exemplarily, the power amplification module may be an LNA.

The iterative calculation module, the iterative calculation module can be used to: receive the target signal from the filter, and receive at least one signal from the at least one second radio frequency link, and according to the target signal calculating a target parameter, calculating a target prediction signal according to at least one signal of the at least one second radio frequency link, and then correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal. Wherein, the target parameter is used to characterize the nonlinear distortion characteristic of the nonlinear component, and the target prediction signal is the second prediction signal of the nonlinear distortion signal.

Specifically, after receiving the target signal, the iterative calculation module calculates the target parameter according to the set first calculation model and the target signal, and calculates the target parameter according to the set second calculation model and the at least one first calculation model. Calculate the target prediction signal for at least one signal of two radio frequency links, wherein the first calculation model is used to represent one of the multiple signals input to the nonlinear component, and the output of the nonlinear component The corresponding relationship between the nonlinear distortion signal with the same frequency band of the one signal and the nonlinear distortion characteristic parameter of the nonlinear component; the second calculation model is used to represent the relationship between at least one signal passing through the nonlinear component and Correspondence between the nonlinear distortion signals generated after the at least one signal passes through the nonlinear components. Wherein, the above set first calculation model and the set second calculation model can be obtained by performing model training in advance.

After the iterative calculation module calculates the target parameter and the target prediction signal, the target parameter is multiplied by the target prediction signal to obtain the nonlinear distortion prediction signal. Wherein, the target parameter is a nonlinear distortion coefficient obtained according to at least one signal actually passing through the nonlinear component and the nonlinear distortion signal actually generated after the at least one signal passes through the nonlinear component, which can more accurately reflect Nonlinear distortion characteristics of nonlinear components. The target prediction signal is obtained only by predicting a nonlinear distortion signal generated after the at least one signal passes through a nonlinear component based on at least one signal of the at least one second radio frequency link. On the basis of a nonlinear distortion prediction signal (that is, the second prediction signal), the corresponding target parameters are further used to correct the estimated nonlinear distortion prediction signal, and a more accurate nonlinear distortion prediction signal (that is, the second prediction signal) can be obtained. The first prediction signal), so as to greatly improve the accuracy of pre-distortion processing on the signal of the first radio frequency link according to the finally obtained nonlinear distortion prediction signal.

In some embodiments of the present application, the feature calculation module further includes a feedback module, and the feedback module can be used to perform delay correction on signals received by the radio frequency link in the base station. The feedback module may be located between the iterative calculation module and the filter, and the feedback module is used to receive the target signal from the filter and at least one channel from the at least one second radio frequency link signal, and perform delay correction processing on the target signal and at least one signal of the at least one second radio frequency link to obtain the target signal and at least one signal of the at least one second radio frequency link with consistent delays signal, and send the obtained signal to the iterative calculation module.

Specifically, referring to FIG. 7 , the feedback module may include a lock module, a correlator, a threshold decision module, a delay calculation module, and a delay alignment module.

The locking module is configured to respectively latch signals with a set time slot length from the at least one second radio frequency link, and send the latched signals to the correlator. Wherein, the number lock module can be realized by a latch.

As an optional implementation, the number lock module can use a fixed time slot lock number, for example, the number lock module can be based on a wireless communication frame structure, with a set duration (such as 10ms) synchronization signal as a reference, a fixed delay Collecting and respectively latching signals from the at least one second radio frequency link, wherein different delays correspond to signals of different time slots. For example, when the fixed delay is 5 ms, after the lock module collects signals with a total time length of 10 ms between the 10th and 20 ms, in the next collection, it collects signals with a total time length of 10 ms between the 15th and 25 ms .

As another optional implementation manner, the lock module may perform signal acquisition and latch according to the control of the threshold judgment module, which will be described in detail below.

The correlator is configured to perform correlation processing on the target signal and the signal from the lock module to obtain a correlation signal, and send the correlation signal to the threshold judgment module, wherein the correlation signal is Nonlinear component signal.

Specifically, when the correlator performs correlation processing on the target signal and the signal from the number-locking module, firstly, according to the signal from the number-locking module, that is, at least one channel of the at least one second radio frequency link signal to determine the target prediction signal, and then perform correlation processing on the target signal and the target prediction signal to obtain the correlation signal. Wherein, the correlator may determine the target prediction signal in the same manner as the iterative calculation module.

The threshold judgment module is configured to receive the correlation signal from the correlator, and judge whether the correlation value (or accumulation value or correlation accumulation value) of the received correlation signal is greater than or equal to a set value, and if so, Then send the related signal to the delay calculation module, otherwise, do not process the related signal.

In some embodiments of the present application, the threshold decision module may also be used to perform latch control on the lock module. Specifically, when the threshold determination module determines that the correlation value of the correlation signal is greater than or equal to the set value, it instructs the lock module to start latching or perform latch update, and respectively latches signals from the at least one The second radio frequency link sets the signal of the time slot length, and replaces the previously latched signal with the currently latched signal. Wherein, the set time slot length can be flexibly set according to actual needs. When the threshold judgment module determines that the correlation value of the correlation signal is less than the set value, instruct the lock module to suspend the latch signal, that is, stop latching the settings from the at least one second radio frequency link time slot length until the threshold judgment module again determines that the correlation value of the correlation signal from the correlator is greater than the set threshold, then the threshold judgment module instructs the lock module to continue latching the signal and updating the lock stored signal.

The delay calculation module is configured to calculate the signal of the first radio frequency link and the at least one second radio frequency link according to the correlation signal when receiving the correlation signal from the threshold judgment module The time delay between the signals of the set time slot length, and send the time delay to the time delay alignment module.

The delay alignment module is configured to, after receiving the delay from the delay calculation module, remove the setting between the target signal and the at least one second radio frequency link according to the delay. Signals with the time delay in the signals with a fixed slot length, and respectively removing the signals with the time delay with the target signal in the signals with the set time slot length of each second radio frequency link, thereby respectively retaining The target signal is a signal with the same time delay as the signal of the at least one second radio frequency link.

Through the above method, there is basically no time delay between the target signal received by the iterative calculation module and the signal of the at least one second radio frequency link, which can ensure the accurate calculation of the corresponding nonlinear distortion prediction signal, thereby improving the subsequent The accuracy of the predistortion process.

After the above iterative calculation module calculates the nonlinear distortion prediction signal, it sends the nonlinear distortion prediction signal to the first radio frequency link, and the first radio frequency link receives the nonlinear distortion prediction signal, according to The nonlinear distortion prediction signal performs pre-distortion processing on signals in a frequency band corresponding to the first radio frequency link. Specifically, after the first radio frequency link subtracts the nonlinear distortion prediction signal from the signal in the frequency band corresponding to the first radio frequency link, the predistortion processing is performed on the signal in the frequency band corresponding to the first radio frequency link. after the signal. The first radio frequency link performs radio frequency processing on the predistorted signal, and then sends it to the optical module, and the optical module can send the signal to the central station.

Optionally, the first radio frequency link includes a pre-distortion processing module, and the pre-distortion processing module is configured to perform pre-distortion processing on a signal in a frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal . Exemplarily, the pre-distortion processing module may be an adder, a multiplier, or a multiplication-add combination module, wherein the multiplication-add combination module has functions of a multiplier and an adder.

In the above embodiment, the base station can calculate the nonlinear distortion characteristic parameters of the nonlinear components based on the signal actually passing through the nonlinear component and the nonlinear distortion signal actually generated after the signal passes through the nonlinear component, which can improve the determination of nonlinear The accuracy of the nonlinear distortion characteristics of a component. After the base station determines the nonlinear distortion parameter of the nonlinear component, it combines the parameter with the signal currently transmitted on the transmission link to estimate the nonlinear distortion prediction signal generated when the signal passes through the nonlinear component, which can improve the determined nonlinear The accuracy of the distortion prediction signal can further pre-distort the signal currently transmitted on the transmission link according to the determined nonlinear distortion prediction signal, so as to realize the nonlinear distortion generated when the signal on the transmission link passes through nonlinear components The correction of the problem can improve the accuracy of nonlinear distortion correction. At the same time, the method has a wide range of applications, and can more accurately predict the nonlinear distortion signals caused by various nonlinear components, and is also convenient for various nonlinear distortion signals. The nonlinear distortion problem caused by linear components is corrected, so the method has strong versatility and adaptability.

The base station provided in the foregoing embodiments of the present application will be described below in combination with specific application scenarios and by taking two second radio frequency links among the plurality of radio frequency links as an example.

Fig. 8 is a schematic diagram of an ROF system provided by an embodiment of the present application. Exemplarily, referring to FIG. 8 , the base station provided by the embodiment of the present application can be applied in a ROF system, and the base station includes at least three radio frequency links, which are respectively the first radio frequency link and the two second radio frequency links link. The three radio frequency links can respectively receive signals of three different frequency bands through the antenna. For example, as shown in FIG. The second signal and the third signal are denoted as f2 and f3 respectively.

When the base station shown in Figure 6 is applied to the ROF system, the base station may also include some components or modules in the ROF system shown in Figure 5 above, as well as other components or modules for signal processing, the following example illustrate.

Each radio frequency link in the base station includes a digital link and an analog link. The digital link may be implemented as a DSP shown in FIG. 8 , and the analog link may be implemented as an LNA shown in FIG. 8 . LNA can be used as a high frequency or intermediate frequency preamplifier or amplifying circuit, which can amplify the power or energy of the signal, and has the advantages of low noise and high gain.

Optionally, each radio frequency link in the base station may further include a filter, an adder, a data processing module, and the like. Among them, the filter can be used to perform filtering processing on the signal, and keep or filter out the signal of a specific frequency band (or frequency). The adder may be used to subtract the nonlinear distortion prediction signal from the signal in the frequency band corresponding to the first radio frequency link, so as to implement pre-distortion processing on the signal in the frequency band corresponding to the first radio frequency link. The data processing module can be used to adjust the transmission rate, gain and other characteristics of the signal on the radio frequency link. Of course, other components or modules may also be included in the radio frequency link. As for which components or modules are specifically included in the radio frequency link, it can be flexibly adjusted according to actual needs, and will not be described in detail here.

The combiner module in the base station is a combiner, and the combiner is used to combine the signals of the three radio frequency links to obtain a combined signal, or the combiner is used to combine the signals in the base station Signals of multiple radio frequency links including the three radio frequency links are combined and processed to obtain a combined signal. Optionally, the function of the combiner may be implemented by an adder, that is, the combiner may be an adder.

The optical module in the base station may include an electro-optic conversion component such as an LD, and the optical module may send the signal converted by the electro-optic conversion component to the central station. Optionally, the optical module in the base station may further include a photoelectric conversion component such as a PD, and the photoelectric conversion component is used to convert a signal from the central station into an electrical signal.

The feature calculation module in the base station may include a photoelectric converter, a filter module, a power amplification module, an analog feedback module, a digital feedback module, an iterative calculation module, and the like. Wherein, the analog feedback module is mainly used to perform analog-to-digital conversion on the signal, which can be realized by an analog-to-digital converter; the digital feedback module is the above-mentioned feedback module, which is used to perform delay correction processing on the signal. For the functions of other components or modules, reference may be made to the descriptions in the above embodiments, and details are not repeated here.

Exemplarily, as shown in FIG. 8, the signal f1 of the first radio frequency link and the signals f2 and f3 received by the two second radio frequency links are sent to the combiner after a series of radio frequency processing, and the combined The circuit breaker completes the combination to obtain the electrical signal of the combination of the signal f1, the signal f2 and the signal f3. In this process, since the feature calculation module has not sampled the signal for calculation, the feature calculation module has no output, and the signal f1 does not change when passing through the adder. The combined electrical signal of signal f1, signal f2 and signal f3 is transmitted to the electro-optical converter of the optical module, and the electro-optical converter can convert the electrical signal into an optical signal and send it to the central station through the optical transmission medium. At the same time, the feature calculation module can sample the optical signal converted by the electro-optical converter, and convert the sampled optical signal into an electrical signal through the photoelectric converter. Among them, the electro-optic converter is a nonlinear component. Due to the nonlinear characteristics of the electro-optic converter, in the process of electro-optical conversion of the electrical signal combined with the signal f1, the signal f2 and the signal f3, the signal f2 and the signal f3 will interact with each other. The modulation effect produces a nonlinear distortion signal of second-order intermodulation, the nonlinear distortion signal is expressed as imd2 (the frequency band of the signal imd2 overlaps with the frequency band of the signal f1), and the output signal of the photoelectric converter includes the signal f1 and the signal f2 , signal f3 and signal imd2, the signal output by the photoelectric converter after photoelectric conversion of the optical signal also includes signal f1, signal f2, signal f3 and signal imd2. After the signal is filtered by a filter, the signal containing only the same frequency band as the signal f1 can be obtained, that is, the target signal, which includes part or all of the signal f1 and the signal imd2 in the same frequency band as the signal f1 (for For convenience of description, it is still referred to as the signal imd2) in the embodiment of the present application. The target signal reaches the digital feedback module after corresponding processing by the power amplification module and the analog feedback module. After the digital feedback module performs delay correction processing on the target signal, signal f2 and signal f3, it sends the obtained corrected target signal, signal f2 and signal f3 to the iterative calculation module. The iterative calculation module calculates the first nonlinear distortion prediction signal according to the corrected target signal, signal f2, and signal f3, and sends the calculated first nonlinear distortion prediction signal to the predistortion processing module on the first radio frequency link such as in the adder. Thereafter, the signal f1 received on the first radio frequency link is processed by an adder, and after being subtracted from the first nonlinear distortion prediction signal (predicted imd2 signal), it is transmitted to the electro-optical converter of the optical module through related components. During the electro-optical conversion process of the signal by the electro-optical converter, the generated imd2 signal and the previously subtracted first nonlinear distortion signal compensate each other, so that the imd2 signal is basically removed from the optical signal obtained by the electro-optical converter, thereby Avoid the interference of imd2 signal to signal f1 as much as possible.

It should be noted that the reception of signals by the first radio frequency link and the two second radio frequency links is synchronous, that is, the three radio frequency links receive corresponding three-way signals at the same time.

Referring to FIG. 9, the processing procedure of the digital feedback module shown in FIG. 8 will be briefly described. As shown in Figure 9, on the one hand, the digital feedback module samples and latches the signals of the two second radio frequency links through the latch module, and sends the latched signals to the correlator, wherein the latched two second The signals of the radio frequency link are represented as the signal f2_latch and the signal f3_latch respectively, and the correlator predicts and calculates the nonlinear distortion signal generated after the signal f2_latch and the signal f3_latch pass through the electro-optical converter, and obtains the corresponding nonlinear distortion prediction signal, and The nonlinear distortion signal and the target signal fb are subjected to correlation processing to obtain a correlation signal of a nonlinear component, and when the threshold judgment module determines that the correlation value of the correlation signal is greater than or equal to a set threshold, the correlation signal is sent to the delay calculation module . The time delay calculation module calculates the time delays between the target signal fb and the signals f2 and f3 according to the relevant signals, and sends them to the time delay alignment module. The time delay alignment module can extract signals with consistent time delays from the target signal fb, signal f2, and signal f3 respectively according to the time delays, and send them to the iterative calculation module. Wherein, the signal extracted by the delay alignment module from the target signal is the signal fb_align, the signal extracted from the signal f2_latch is the signal f2_latch_align, the signal extracted from the signal f3_latch is the signal f3_latch_align, and there is no difference between the signal fb_align, the signal f2_latch_align and the signal f3_latch_align There is a delay.

It should be noted that the above-mentioned system architecture shown in FIG. 8 or FIG. 9 is only an illustration of the system architecture applicable to the embodiment of the present application. Compared with the system architecture shown in FIG. 8 or FIG. 9, the system architecture applicable to the embodiment of the application Other entities can also be added, or some entities can be reduced, and other structures can also be added or some structures (or components) can be reduced in the terminal structure shown in FIG. 8 or FIG. 9 . The various components shown in Fig. 8 or Fig. 9 above are only examples of components that can realize corresponding functions, and each component can also be replaced with other components that can realize corresponding functions.

In the above embodiments, the base station has a mixed digital-analog structure, so in terms of the function design of the base station, it has greater flexibility than the base station architecture with a conventional pure analog design, and at the same time has unique advantages in performance. Among them, in the receiving link of the ROF system, by designing a feedback channel including the photoelectric conversion module and the feature calculation module in the optical module, the coupling sampling of the nonlinear component signal is realized through the internal feedback coupling of the optical module, and through the feedback The channel is looped back to the head-end digital link (for example, the above-mentioned first radio frequency link), so that the modeling calculation of the nonlinear distortion signal and the pre-distortion correction of the radio frequency link signal are realized at the base station side. Therefore, the nonlinear distortion correction scheme shown in FIG. 8 or FIG. 9 may also be called a small loop correction scheme. Through this solution, the nonlinear distortion generated by the nonlinear components in the base station can be solved, and the impact of the head-end nonlinearity on the entire ROF system can be reduced.

It should be noted that, in the above embodiments, the application of the nonlinear signal processing structure and method provided by the present application in the receiving link of the ROF system is used as an example for illustration. In practical applications, the nonlinear signal processing structure provided by the above embodiments The sum method can also be applied in the transmission link of the ROF system. In addition, the nonlinear signal processing structure and method provided by the above embodiments can be applied not only at the base station side, but also at the central station side. For specific applications, refer to relevant introductions in the above embodiments, and details will not be repeated here.

In the solution provided by the embodiment of the present application, the optical module in the base station is compared with the optical module in the existing base station structure, and a coupling port is added, that is, the third port described in the above embodiment. In the embodiment of the present application The signal transmission on the feedback link is realized via this port. Exemplarily, FIG. 10 is a comparative schematic diagram of an optical module structure provided by an embodiment of the present application. As shown in the schematic diagram of (a) in Figure 10, the single-transmit-single-receive (1T1R, that is, one antenna is responsible for signal transmission and reception) analog optical module in the current base station structure is a three-port module, including one for uplink An input electrical port for receiving electrical signals in the link, an output electrical port for sending signals in the downlink, and a transmission optical port for transmitting optical signals, which are respectively port 1 shown in (a) schematic diagram , port 2, and port 3. In the solution of the embodiment of the present application, the optical module in the base station is a four-port module, including an input electrical port for receiving electrical signals in the uplink, and an output electrical port for sending signals in the downlink. port, a transmission optical port for transmitting optical signals, and an electrical signal coupling port for transmitting sampling, which are respectively port 1, port 2, port 3 and port 4 shown in (b) schematic diagram. Wherein, the port 2, the port 3 and the port 4 are respectively the first port, the second port and the third port described in the above embodiment. For its specific application manner, reference may be made to the introduction in the foregoing embodiments, which will not be repeated here.

It should be noted that the structure of the optical module in the embodiment of the present application shown in FIG. 8 , FIG. 9 or FIG. 10 is the structure of a 1T1R optical module. The optical modules responsible for the sending and receiving of signals respectively) can also add multiple feedback channels including the feature calculation module provided by the above-mentioned embodiments of the present application to realize the same functions as above. Among them, for a multi-T multi-R optical module, each 1T1R may correspond to one feedback channel (including the feature calculation module and front and back links), or multiple 1T1Rs may share one feedback channel.

FIG. 11 is a schematic diagram of a simplified structure of a base station structure provided by an embodiment of the present application. In some embodiments of the present application, as shown in FIG. 11 , in the above-mentioned small loop correction scheme shown in FIG. 8 or FIG. 9 , the structure on each radio frequency link can be divided into an analog link and a forward link , where the analog link is mainly used to implement analog signal processing functions such as signal transmission and analog-to-digital conversion, and the forward link is used to implement digital signal processing functions related to nonlinear distortion signal prediction and pre-distortion correction. For example, the two first The forward link part of the second radio frequency link may be used to send signals to the feature calculation module, etc., and the forward link part of the first radio frequency link may be used for predistortion correction processing. The optical module mainly includes an electro-optical conversion module and a photoelectric conversion module. Reference may be made to the introduction in the foregoing embodiments. The feedback link can be combined with the existing system link to build a feedback channel, and realize the time delay alignment of the useful signal and the nonlinear distortion signal, mainly including the above-mentioned feedback module. The calculation link can use the useful signal processed by the feedback link and the nonlinear distortion signal to perform calculation modeling, calculate the nonlinear distortion prediction signal, and feed it back to the forward link of the first radio frequency link, so that the first radio frequency The forward link of the radio frequency link performs predistortion processing on the signal on the first radio frequency link according to the nonlinear distortion prediction signal, so as to compensate the nonlinear distortion in the link.

It should be noted that the above-mentioned division of the base station structure is schematic, and is only a logical function division. In actual implementation, there may be other division methods. In addition, each functional module in each embodiment of the present application may be a separate It exists physically, or two or more modules can be integrated in one module.

Embodiment two

Fig. 12 is a schematic diagram of a base station and a central station provided by an embodiment of the present application. As shown in Fig. 12, in this embodiment, the base station may include multiple radio frequency links (such as the radio frequency chain shown in Fig. 12 1, radio frequency link 2), optical module, feature calculation module; wherein, the number of the plurality of radio frequency links is greater than or equal to 2.

It should be noted that, for the convenience of introduction, only the case where the base station includes two radio frequency links is illustrated in FIG. 12 , and there may be more or less radio frequency links in the actual base station, which will not be repeated here.

In the base station, each radio frequency link is used to receive one signal of a corresponding frequency band through the antenna, and transmit the one signal to the optical module after performing radio frequency processing on the one signal.

The optical module is configured to perform electro-optic conversion processing on the multiple signals from the multiple radio frequency links, obtain an optical signal including the processed multiple signals, and send the optical signal to the center Station, receives the target signal from the central station, performs photoelectric conversion processing on the target signal, and sends the processed target signal to the feature calculation module, wherein there are The first radio frequency link and at least one second radio frequency link, the optical module includes nonlinear components, and the signal of the at least one second radio frequency link passes through the nonlinear components to generate a nonlinear distorted signal, The frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link, and the optical signal also includes the nonlinear distortion signal; the target signal includes the frequency band corresponding to the first radio frequency link signal in the frequency band.

Optionally, the base station further includes a combiner module (not shown in FIG. 12 ), the combiner module is used to receive multiple signals from the multiple radio frequency links, and combine the multiple signals Perform combination processing to obtain a combination signal, and send the combination signal to the optical module. The optical module is used to receive the combined signal from the combined module, and perform electro-optical conversion processing on the combined signal to obtain the optical signal. Exemplarily, the combining module may be a combiner.

The feature calculation module is configured to receive the target signal from the optical module; calculate a nonlinear distortion prediction signal according to the target signal and at least one signal from the at least one second radio frequency link, and calculate the The nonlinear distortion prediction signal is sent to the first radio frequency link, wherein the nonlinear distortion prediction signal is a first prediction signal of the nonlinear distortion signal.

In this embodiment, the optical module includes an electro-optical conversion module, the electro-optical conversion module is used to perform electro-optical conversion processing on the multi-channel signal to obtain an optical signal, and the electro-optical conversion module includes the nonlinear component , the nonlinear component can be used to perform electro-optical conversion processing on signals. Exemplarily, the electro-optic conversion module may be an LD.

After the optical module sends the converted optical signal to the central station, it can receive the target signal from the central station, perform photoelectric conversion processing on the target signal, and send the processed target signal to the Feature calculation module. Wherein, as an optional implementation manner, the optical module may directly receive the target signal from the central station, and send the target signal to the feature calculation module. As another optional implementation manner, the optical module may receive a downlink signal from the central station, perform photoelectric conversion processing on the downlink signal, and send the processed downlink signal to the feature calculation module, wherein the downlink signal includes the target signal and other signals to be sent to the base station. In this manner, the feature calculation module may obtain the target signal by receiving the downlink signal from the optical module and performing filtering processing on the downlink signal.

In the feature calculation module, the filtering module is configured to receive the downlink signal from the optical module, and filter the downlink signal to obtain the target signal. Exemplarily, the filtering module is a filter. For the functions of the iterative calculation module, reference may be made to the description of the iterative calculation module in Embodiment 1 above, which will not be repeated here.

Optionally, the feature calculation module may also include a frequency division module, the frequency division module is connected to the optical module and the filter module, and the frequency division module may be used to receive the downlink from the optical module signal, performing frequency division processing on the downlink signal to obtain a signal in the frequency band corresponding to the first radio frequency link, and sending the signal in the frequency band corresponding to the first radio frequency link to the filter, then the filter It can be used to perform filtering processing on the signal in the frequency band corresponding to the first radio frequency link to obtain the target signal.

In some embodiments of the present application, the feature calculation module further includes a feedback module. For the structure and function of the feedback module, please refer to the description of the feedback module in the first embodiment above, and will not be repeated here.

In addition, it should be noted that in this embodiment, unless otherwise specified, reference can be made to the relevant descriptions in the first embodiment above for the structure, function, and characteristics of each module in the base station, and no further description will be given in this embodiment. restate.

In this embodiment, the central station may include an optical module and a signal processing module.

The optical module is configured to receive an optical signal from the base station, perform photoelectric conversion processing on the optical signal to obtain an electrical signal, and send the electrical signal to the signal processing module, wherein the electrical signal contains a nonlinear Distorted signals, multiple signals received by multiple radio frequency links of the base station through antennas, the number of the multiple radio frequency links is greater than or equal to 2, and the first radio frequency link and the first radio frequency link exist in the multiple radio frequency links At least one second radio frequency link, the base station includes nonlinear components, and the signal of the at least one second radio frequency link passes through the nonlinear components to generate the nonlinear distortion signal, and the nonlinear distortion The frequency band of the signal overlaps with the frequency band corresponding to the first radio frequency link.

In some embodiments of the present application, the optical module of the central station may include a photoelectric conversion module, and the photoelectric conversion module is configured to receive an optical signal from a base station and convert the optical signal into an electrical signal. Optionally, the photoelectric conversion module includes nonlinear components. Exemplarily, the photoelectric conversion module may be a PD.

Exemplarily, as shown in FIG. 12, after the optical module of the base station obtains an optical signal through the electro-optical conversion module, the optical signal is sent to the central station, and the optical module of the central station transmits the optical signal through the photoelectric conversion module The optical signal is converted into an electrical signal and sent to a signal processing module.

The signal processing module is configured to receive the electrical signal from the optical module, extract the target signal of the frequency band corresponding to the first radio frequency link from the electrical signal, and send the target signal to the Described optical module.

Optionally, the signal processing module includes a filtering module, and the filtering module is configured to receive the electrical signal from the optical module, perform filtering processing on the electrical signal, obtain the target signal, and send it to the Described optical module.

The optical module is further configured to perform electro-optical conversion processing on the target signal, and send the processed target signal to the base station. Specifically, after the optical module receives the target signal from the signal processing module, as an optional implementation manner, the optical module may directly and separately send the target signal to the base station. As another optional implementation manner, the optical module may perform electrical-optical conversion processing on the target signal and other signals to be sent to the base station, to obtain the target signal and other signals to be sent to the base station the downlink signal of the signal, and send the downlink signal to the base station.

In some embodiments of the present application, the optical module of the central station may further include an electrical-to-optical conversion module, and the electrical-to-optical conversion module is configured to convert an electrical signal into an optical signal, and then send the optical signal to the base station. Optionally, the electro-optic conversion module includes nonlinear components. Exemplarily, the electro-optic conversion module may be an LD.

In some embodiments of the present application, the start frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency. Wherein, in a possible situation, there is a second radio frequency link in the plurality of radio frequency links, and the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, The second frequency is twice the cutoff frequency of the frequency band corresponding to the one second radio frequency link. In another possible situation, there are two second radio frequency links among the plurality of radio frequency links, and the first frequency is the sum of starting frequencies of corresponding frequency bands of the two second radio frequency links, The second frequency is the sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the difference between the start frequencies of the frequency bands corresponding to the two second radio frequency links, so The second frequency is the difference between the cut-off frequencies of the corresponding frequency bands of the two second radio frequency links.

In the above embodiment, after the base station sends the signal passing through the nonlinear components and the nonlinear distortion signal generated by the signal passing through the nonlinear components to the central station, the central station obtains the target signal based on the signal, and then sends the target signal back to base station, and the base station calculates the nonlinear distortion characteristic parameters of the nonlinear components according to the target signal. The accuracy of the nonlinear distortion characteristics of linear components. After the base station determines the nonlinear distortion parameter of the nonlinear component, it combines the parameter with the signal currently transmitted on the transmission link to estimate the nonlinear distortion prediction signal generated when the signal passes through the nonlinear component, which can improve the determined nonlinear The accuracy of the distortion prediction signal can further pre-distort the signal currently transmitted on the transmission link according to the determined nonlinear distortion prediction signal, so as to realize the nonlinear distortion generated when the signal on the transmission link passes through nonlinear components The correction of the problem improves the accuracy of nonlinear distortion correction. On the other hand, the signal on which the base station calculates the nonlinear distortion characteristic parameters is passed back by the central station, so the transmission path of the signal includes some transmission links in the central station, and the nonlinear distortion problem in the base station The correction method can correct the entire link where the nonlinear components are located. Therefore, while correcting the nonlinear distortion problems in the base station, this scheme can also correct some nonlinear distortion problems in the central station, thereby improving the communication between the central station and the central station. The accuracy of communication between base stations.

The base station and the central station provided in the above embodiments of the present application will be described below in combination with specific application scenarios, taking one second radio frequency link among the plurality of radio frequency links as an example, in combination with specific examples.

Fig. 13 is a schematic diagram of an ROF system provided by an embodiment of the present application. Exemplarily, referring to FIG. 13 , the base station and the central station provided by the embodiment of the present application can be applied in a ROF system, and the base station includes at least two radio frequency links, which are respectively a first radio frequency link and a second radio frequency link road. The two radio frequency links can respectively receive signals of two different frequency bands through antennas. For example, as shown in FIG. The road signal is denoted as f5.

When the base station shown in Figure 13 is applied to the ROF system, the base station may also include some components or modules in the ROF system shown in Figure 5 above, and other components or modules for signal processing, specifically Refer to the relevant introduction in the first embodiment above, which will not be repeated here.

Exemplarily, as shown in FIG. 13, the signal f4 received by the first radio frequency link and the signal f5 received by the second radio frequency link are sent to the combiner after a series of radio frequency processes, and the combiner completes Combined to obtain the electrical signal of signal f4 and signal f5 combined, the electrical signal is transmitted to the electro-optical converter of the optical module, the electro-optical converter can convert the electrical signal into an optical signal and send it to the central station through the optical transmission medium. Among them, the electro-optical converter is a nonlinear component. Due to the nonlinear characteristics of the electro-optic converter, in the process of electro-optical conversion of the electrical signal combined with the signal f4 and the signal f5, the frequency component of the signal f5 will undergo intermodulation. The nonlinear distortion signal of the second-order intermodulation, the nonlinear distortion signal is expressed as imd2 (the frequency band of the signal imd2 overlaps with the frequency band of the signal f4), and the signal sent by the electro-optical converter of the base station to the central station includes the signal f4, Signal f5 and signal imd2. After receiving the optical signal, the photoelectric conversion module of the central station converts the optical signal into an electrical signal, and sends the electrical signal to the signal processing module. The signal processing module of the central station can obtain the signal containing only the same frequency band as the signal f4 after filtering the electrical signal through a filter, that is, the target signal, which includes the signal f4 and the signal imd2 in the same frequency band as the signal f4 Part or all of the signals (for ease of description, it is still referred to as the signal imd2 in this embodiment of the application). The target signal and other signals to be sent to the base station are sent to the base station together after passing through the electro-optic converter of the central station. After the photoelectric converter of the base station receives the signal from the central station, it performs photoelectric conversion processing on the signal to obtain a corresponding electrical signal, and sends it to the feature calculation module. The characteristic calculation module of the base station performs frequency division processing on the electrical signal through the frequency division module to obtain a signal corresponding to the frequency band of the first radio frequency link, and performs filtering processing on the signal through a filter to obtain a target signal, and the target signal is passed through the power After corresponding processing by the amplification module and the analog feedback module, it reaches the digital feedback module. After the digital feedback module performs delay correction processing on the target signal and signal f5, the obtained signal is sent to the iterative calculation module. The iterative calculation module calculates the first nonlinear distortion prediction signal according to the target signal and signal f5, and sends the calculated first nonlinear distortion prediction signal to the adder on the first radio frequency link, and processes it through the adder, After subtracting the first nonlinear distortion prediction signal (predicted imd2 signal) from the signal f4 on the first radio frequency link, it is transmitted to the electro-optical converter of the optical module through related components. During the electro-optical conversion process of the signal by the electro-optical converter, the generated imd2 signal and the previously subtracted first nonlinear distortion signal compensate each other, so that the imd2 signal is basically removed from the optical signal obtained by the electro-optical converter, thereby Avoid the interference of imd2 signal to signal f4 as much as possible.

Wherein, it should be noted that, in the central station shown in Fig. 13, the photoelectric converter and the electro-optical converter are also nonlinear components, if the signal from the base station passes through the photoelectric converter or the electro-optical converter also generates If there is a non-linear distortion signal overlapping the frequency band of the signal f4, part or all of the signals in the non-linear distortion signal overlapping the frequency band of the signal f4 will also be carried in the target signal and sent back to the base station, then the base station When calculating the nonlinear distortion prediction signal based on the target signal, the nonlinear distortion problem in the process of the signal passing through the central station can be considered, and some nonlinear distortion in the central station can be corrected during the pre-distortion process, so as to further Improve performance in correcting nonlinear distortions of ROF systems.

In the above-mentioned embodiment, the signal starts from the receiving port of the air interface antenna of the base station, undergoes a radio frequency link in the base station, and the electro-optical converter of the optical module generates nonlinearity, and then transmits through the optical fiber, receives it at the photoelectric converter of the central station, and then passes through the central station. The signal processing of the station is sent by the electro-optical converter on the transmitting side, and then received by the photoelectric converter of the base station through the optical fiber loopback. After frequency division, it is coupled to the feedback link through the feedback channel for nonlinear distortion signal prediction and other processing. The original optical modules of the base station and the central station can be used to realize the large-loop sampling of the nonlinear distortion signal, which is sent to the feature calculation module of the base station to predict the nonlinear distortion signal. Therefore, the modeling calculation of the nonlinear distortion signal on the link between the base station and the central station and the pre-distortion correction of the radio frequency link signal are realized on the base station side. Therefore, the above nonlinear distortion correction scheme shown in FIG. 13 may also be referred to as a giant loop correction scheme. Through this solution, the nonlinear distortion generated by the nonlinear components in the base station and the central station can be solved, and the influence of the nonlinearity in the base station and the central station on the entire ROF system can be reduced.

Embodiment three

FIG. 14 is a schematic diagram of a central station provided by an embodiment of the present application. As shown in FIG. 14 , in this embodiment, the central station may include an optical module, a signal processing module, and a feature calculation module.

The optical module is configured to receive an optical signal from at least one base station, perform photoelectric conversion processing on the optical signal of each base station in the at least one base station, obtain an electrical signal of each base station, and convert the electrical signal of each base station to sent to the signal processing module and the feature calculation module. Wherein, the electrical signal of any base station includes nonlinear distortion signals, multiple signals received by multiple radio frequency links of the base station through antennas, the number of the multiple radio frequency links is greater than or equal to 2, and the multiple There are a first radio frequency link and at least one second radio frequency link in the radio frequency links, the base station contains nonlinear components, and the signal of the at least one second radio frequency link is generated after passing through the nonlinear components For the nonlinear distorted signal, a frequency band of the nonlinear distorted signal overlaps with a frequency band corresponding to the first radio frequency link.

Wherein, the optical module sends the electrical signal of each base station to the signal processing module respectively through different links. The optical module sends the electrical signal of each base station to the feature calculation module through different links.

The feature calculation module is used to respectively receive the electrical signal from each base station of the optical module; respectively perform feature calculation processing on the electrical signal of each base station to obtain a nonlinear distortion prediction signal corresponding to each base station, and respectively The nonlinear distortion prediction signal corresponding to each base station is sent to the signal processing module; wherein, the feature calculation processing on the electrical signal of any base station includes the following steps: extracting the first radio frequency chain from the electrical signal target signal in a corresponding frequency band, and at least one signal from the at least one second radio frequency link is respectively extracted from the electrical signal; according to the target signal and at least one signal of the at least one second radio frequency link One channel of signals calculates the nonlinear distortion prediction signal, wherein the nonlinear distortion prediction signal is a first prediction signal of the nonlinear distortion signal.

The signal processing module is configured to respectively receive electrical signals from each base station of the optical module; perform radio frequency processing on the electrical signals of the at least one base station to obtain a target combining signal; wherein, the target combining signal includes The signal of the frequency band corresponding to the first radio frequency link; the radio frequency processing may include combination processing and frequency division processing; respectively receive the nonlinear distortion prediction signal corresponding to each base station from the feature calculation module; The nonlinear distortion prediction signals corresponding to the base stations perform distortion correction processing on the target combined signal.

In some embodiments of the present application, the start frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency, wherein, in a possible situation , there is a second radio frequency link in the plurality of radio frequency links, the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, and the second frequency is the The second radio frequency link corresponds to twice the cutoff frequency of the frequency band. In another possible situation, there are two second radio frequency links among the plurality of radio frequency links, and the first frequency is the sum of starting frequencies of corresponding frequency bands of the two second radio frequency links, The second frequency is the sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the difference between the start frequencies of the frequency bands corresponding to the two second radio frequency links, so The second frequency is the difference between the cut-off frequencies of the corresponding frequency bands of the two second radio frequency links.

In this embodiment, the optical module includes a photoelectric conversion module, and the photoelectric conversion module is configured to respectively perform photoelectric conversion processing on the optical signals from the at least one base station to obtain electrical signals. Optionally, the photoelectric conversion module includes nonlinear components, and the nonlinear components can be used to perform photoelectric conversion processing on signals. Exemplarily, the photoelectric conversion module may be a PD.

In this embodiment, for the structure and function of the feature calculation module, reference may be made to the description of the feature calculation module in the first embodiment above, and details are not repeated here.

In some embodiments of the present application, the signal processing module includes a radio frequency processing module, a digital processing and compensation module. The radio frequency processing module is configured to perform radio frequency processing on the signal corresponding to each base station received by the optical module, for example, it may include: performing combination processing on the electrical signals of the at least one base station to obtain a combined signal, and The combined signal is subjected to frequency division processing to obtain a signal of a frequency band corresponding to each radio frequency link. Wherein, the signal of the frequency band corresponding to each radio frequency link includes the signal of the frequency band corresponding to the at least one base station and the non-linear distortion signal overlapping with the frequency band. For example, as shown in FIG. 14 , a signal of a frequency band corresponding to the first radio frequency link, and a signal of a frequency band corresponding to the second radio frequency link. Wherein, the signal in the frequency band corresponding to the first radio frequency link is the target combining signal. The digital processing and compensation module is used to sequentially perform distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to each base station. Specifically, the digital processing and compensation module sequentially subtracts the nonlinear distortion prediction signal corresponding to each base station from the target combined signal to obtain the target combined signal from which the nonlinear distortion signal has been removed.

Exemplarily, when the at least one base station includes the first base station and the second base station, and each base station receives two signals through two radio frequency links, the signal sent by the first base station to the central station includes the signal of the first base station A signal on the first radio frequency link, a signal of the second radio frequency link of the first base station, and a nonlinear distorted signal generated after the signal of the second radio frequency link passes through a nonlinear component. The signal sent by the second base station to the central station includes the signal on the first radio frequency link of the second base station, the signal of the second radio frequency link of the first base station, and the signal of the second radio frequency link after passing through the nonlinear components The resulting non-linear distortion signal. Then, the combined signal obtained by combining the electrical signals of the at least one base station by the radio frequency processing module includes at least the above six signals. The radio frequency processing module performs frequency division processing on the combined signal to obtain the target combined signal (including the signal of the first radio frequency link of the first base station, the nonlinear distortion signal from the first base station, and the second The signal of the first radio frequency link of the base station, the nonlinear distortion signal from the second base station), and then perform distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to each base station. Specifically, the signal processing module may first perform distortion correction processing on the target combined signal according to the nonlinear distortion prediction signal corresponding to the first base station to obtain the first target combined signal, and then according to the second base station The corresponding nonlinear distortion prediction signal performs distortion correction processing on the first target combined signal to obtain a second target combined signal. Wherein, the signal processing module obtains the first target combined signal by subtracting the target combined signal from the nonlinear distortion prediction signal corresponding to the first base station, and obtains the first target combined signal by Subtracting the nonlinear distortion prediction signal corresponding to the second base station to obtain the second target combined signal.

In some embodiments of the present application, when the radio frequency processing module performs radio frequency processing on the signals corresponding to each base station received by the optical module, it may also perform combined processing on the electrical signals of the at least one base station to obtain combined signal. Then the combined signal is sent to the digital processing and compensation module as the target combined signal. The digital processing and compensation module is used to sequentially subtract the target combined signal from the nonlinear distortion prediction signal corresponding to each base station to obtain the combined signal of the at least one base station after the nonlinear distortion signal is removed. During subsequent processing of the combined signal of the at least one base station, the central station may perform frequency division processing on the signal to obtain a signal in a frequency band corresponding to each radio frequency link.

In some embodiments of the present application, the signal processing module may also only include a digital processing and compensation module, and then the digital processing and compensation module may separately receive the optical module according to the nonlinear distortion prediction signal corresponding to each base station. Distortion correction processing is performed on the signals of each base station, thereby realizing independent processing of signals from different base stations.

In some embodiments of the present application, the feature calculation module may further include a signal control module in addition to the specific structure described in the first or second embodiment above. The signal control module is used to selectively control the electrical signal from the at least one base station of the optical module, so that the feature calculation module only receives the electrical signal from one base station at a time. Exemplarily, the signal control module may be a single-pole multi-throw switch, wherein the fixed end of the single-pole multi-throw switch is connected to the filter module in the characteristic calculation module, and the movable end of the single-pole multi-throw switch is respectively connected to the transmission of the at least one The link connection of the electrical signal of the base station. The electrical signal of a certain base station transmitted by a certain link can be selected to be transmitted to the characteristic calculation module through the single-pole multi-throw switch, so as to facilitate the calculation of the nonlinear distortion prediction signal for the base station.

In some embodiments of the present application, there may be multiple feature calculation modules in the central station, that is, the central station sets a corresponding feature calculation module for each connected base station, and then the photoelectric conversion module of the central station obtains electrical signals from at least one base station. After receiving the signal, the central station couples the signal to the corresponding feature calculation module on the transmission link corresponding to each signal, and calculates the nonlinear distortion prediction signal of the corresponding base station through the feature calculation module. After the feature calculation module corresponding to each base station determines the nonlinear distortion prediction signal corresponding to the base station, it sends the determined nonlinear distortion prediction signal to the signal processing module respectively.

As an optional implementation, the signal processing module can respectively perform distortion correction processing on the electrical signal of each base station according to the nonlinear distortion prediction signal corresponding to each base station, so that each individual signal component can be nonlinearly constructed. Mode and distortion correction processing, so as to ensure the best performance.

As another optional implementation manner, after the signal processing module performs combination processing and frequency division processing on the electrical signal of the at least one base station, it sequentially performs frequency division The obtained electrical signal is subjected to distortion correction processing, so that the signals after aggregation and channel separation can be separated to achieve the equivalent effect of multi-channel signal separation, and then nonlinear modeling and distortion correction processing can be performed for each component signal, which can Avoid setting up additional physical channels.

It should be noted that in this embodiment, unless otherwise specified, the structures, functions, and characteristics of some modules can refer to the relevant introductions in the above-mentioned Embodiment 1 or Embodiment 2, and will not be described in detail in this embodiment. For example, the center For the structure of the feature calculation module in the station, for the structure other than the signal control module, refer to the related introduction about the feature calculation module in the first embodiment above.

In the above embodiment, the central station can calculate the nonlinear distortion of the nonlinear component based on the signal actually passing through the nonlinear component (in the base station or the central station) and the nonlinear distortion signal actually generated after the signal passes through the nonlinear component The characteristic parameter can improve the accuracy of determining the nonlinear distortion characteristic of the nonlinear component. After the central station determines the nonlinear distortion parameters of the nonlinear components, it combines the parameters with the current transmission signal on the transmission link to estimate the nonlinear distortion prediction signal generated when the signal passes through the nonlinear components, which can improve the determined nonlinear distortion parameters. The accuracy of the linear distortion prediction signal can further distort the signal currently transmitted on the transmission link according to the determined nonlinear distortion prediction signal, so as to realize the nonlinear distortion generated when the signal on the transmission link passes through nonlinear components The correction of the problem improves the accuracy of nonlinear distortion correction. At the same time, the central station can perform nonlinear distortion correction processing on signals from multiple base stations, which improves the performance and efficiency of nonlinear distortion correction.

The base station provided by the above-mentioned embodiments of the present application will be described below in combination with specific application scenarios, taking a first radio frequency link and a second radio frequency link in each base station as an example, and specific examples.

Fig. 15 is a schematic diagram of an ROF system provided by an embodiment of the present application. Exemplarily, referring to FIG. 15 , the central station provided by the embodiment of the present application can be applied to an ROF system, and the central station includes an optical module, a feature calculation module, and a signal processing module. For details, refer to relevant introductions in the foregoing embodiments. The ROF system further includes n base stations, where n is a positive integer. Among the n base stations, each base station includes two radio frequency links, namely a first radio frequency link and a second radio frequency link. The two radio frequency links can respectively receive signals of two different frequency bands through the antenna. For example, as shown in FIG. The second signal received by the channel is expressed as f2_N, where N is less than or equal to n and is a positive integer. Among the n base stations, the frequency bands corresponding to the first radio frequency links of each base station are the same, and the second radio frequency links of each base station The frequency bands corresponding to the channels are the same, and the signals of the second radio frequency links of each base station pass through nonlinear components to generate nonlinear distortion signals overlapping with the frequency bands corresponding to the first radio frequency links.

Exemplarily, as shown in FIG. 15, the signal f1_N received by the first radio frequency link of the Nth base station and the signal f2_N received by the second radio frequency link are sent to the combiner after a series of radio frequency processing, and then The combiner completes the combination to obtain the combined electrical signal of signal f1_N and signal f2_N, and the electrical signal is transmitted to the electro-optical converter of the optical module, which can convert the electrical signal into an optical signal and send it to central station. Among them, the electro-optical converter is a nonlinear component. Due to the nonlinear characteristics of the electro-optic converter, in the process of electro-optical conversion of the electrical signal combined with the signal f1_N and the signal f2_N, the frequency component of the signal f2_N will undergo intermodulation. The nonlinear distortion signal of the second-order intermodulation, the nonlinear distortion signal is expressed as imd2_N (the frequency band of the signal imd2_N overlaps with the frequency band of the signal f1_N), then the signal actually sent by the electro-optical converter of the base station to the central station contains the signal f1_N , signal f2_N and signal imd2_N, expressed as f1_N+f2_N+imd2_N. After receiving the optical signal, the photoelectric conversion module of the central station converts the optical signal into an electrical signal, and sends the electrical signal to the signal processing module. The signal processing module of the central station performs combination processing and frequency division processing on the electrical signals of the at least one base station through the radio frequency processing module to obtain signals corresponding to frequency bands of different radio frequency links. The signal obtained after frequency division at least includes a signal of a frequency band corresponding to the first radio frequency link and a signal of a frequency band corresponding to the second radio frequency link. Wherein, the signals of the frequency band corresponding to the first radio frequency link at least include some or all of the signals f1_1~f1_n and the non-linear distortion signals overlapping with the frequency bands of the signals f1_1~f1_n respectively (indicated as F1+imd2 in FIG. 15 , wherein, F1+imd2=f1_1+imd2_1+f1_2+imd2_2+...+f1_n+imd2_n), the signal of the frequency band corresponding to the second radio frequency link at least includes signals f2_1～f2_n (represented as F2 in Figure 15, where F2=f2_1 +f2_2+…+f2_n). The feature calculation module calculates the nonlinear distortion prediction signal corresponding to each base station according to the electrical signal (f1_N+f2_N+imd2_N) of each base station, and sends it to the signal processing module. The signal processing module sequentially subtracts the nonlinear distortion prediction signal corresponding to each base station from the signal in the frequency band corresponding to the first radio frequency link to implement nonlinear distortion correction for the signal in the frequency band corresponding to the first radio frequency link.

In the above-mentioned solutions of Embodiment 1 and Embodiment 2, both are one-to-one nonlinear distortion correction, that is, one nonlinear distortion correction structure corresponds to one base station module or communication link. In a cellular mobile communication system, usually a central station is connected to multiple base stations (for example, a central station is connected to eight base stations, etc.), and these multiple base stations share the resources of a central station, so the signals of multiple base stations will eventually converge. to a central station. Therefore, in the third embodiment above, by setting the correction link at the central station, one driver and multiple corrections at the central station are realized, that is, the central station can not only correct the nonlinear distortion caused by the nonlinear device in the base station, but also correct the Nonlinear distortion caused by nonlinear devices.

In the above-mentioned embodiments, a new ROF architecture based on digital-analog hybrid is provided, which is conducive to adopting flexible digital links, more accurately solving the nonlinear distortion problem of analog devices in the ROF network, and solving the non-linear distortion caused by optical devices and the like. The constraint of the linear component on the frequency planning of the ROF system realizes the high-performance and low-cost design of ROF, which can improve the performance of 5G and future multi-mode large-bandwidth high-speed transmission and enable low-cost deployment of sites.

It can be understood that, in the above-mentioned embodiments, the solution to the nonlinear distortion problem caused by the nonlinear components in the optical module of the base station is used as an example to introduce the solution provided by the application, but the application scenario of the solution in the application is not limited to this . For the nonlinear distortion problem caused by any nonlinear element in the base station or central station, the scheme provided by this application can effectively solve it. In addition, the scheme provided by this application is mainly described according to the correction of nonlinear distortion components. In fact, The scheme provided in this application can also be applied to linear distortion component correction. For the specific implementation manners of the solution in each of the above scenarios, reference may be made to the introduction of the above embodiments, and no further description is given here.

Based on the above embodiments and the same idea, this embodiment of the present application also provides a nonlinear signal processing method, which can be applied to a base station or a central station. As shown in Figure 16, when the nonlinear signal processing method provided in the embodiment of the present application is applied to a base station, the method includes:

S1601: The base station calculates target parameters according to the target signal, wherein the target signal includes: a first signal passing through a nonlinear component, and a nonlinear distortion signal generated after at least one second signal passes through a nonlinear component, and the nonlinear The frequency band of the distorted signal overlaps with the frequency band of the first signal, and the target parameter is used to characterize the nonlinear distortion characteristic of the nonlinear component.

Wherein, the frequency band of the first signal is the first frequency band, and the frequency bands of the signals in the at least one second signal may be the same or different.

Exemplarily, the first signal may be the signal S _F3 in the scene one shown in FIG. 3 , and the at least one second signal may include the signal S _F1 and the signal S _F2 in the scene two shown in FIG. 3 ; Alternatively, the first signal may be the signal S _F3 in the second scene shown in FIG. 3 , and the at least one second signal may include the signal S _F1 and the signal S _F2 in the second scene shown in FIG. 3 ; or, The first signal may be the signal S _F3 in the third scene shown in FIG. 3 , and the at least one second signal may include the signal S _F1 in the third scene shown in FIG. 3 .

In some embodiments of the present application, the base station may calculate the target parameters according to the set first calculation model and the target signal, wherein the first calculation model is used to represent the multi-channel signals input to the nonlinear components The corresponding relationship between one channel of signal, the nonlinear distortion signal output by the nonlinear component with the same frequency band as the one of the signal, and the nonlinear distortion characteristic parameters of the nonlinear component.

S1602: The base station calculates a target prediction signal according to the at least one second signal, where the target prediction signal is a prediction signal of the nonlinear distortion signal.

Wherein, the base station may calculate the target prediction signal according to the set second calculation model and the at least one second signal, wherein the second calculation model is used to represent the relationship between the at least one signal passing through the nonlinear component and the The corresponding relationship between the nonlinear distortion signals generated after the at least one signal passes through the nonlinear components.

S1603: The base station corrects the target prediction signal according to the target parameter to obtain a nonlinear distortion prediction signal.

Wherein, the nonlinear distortion prediction signal is a modified prediction signal of the nonlinear distortion signal.

When correcting the target prediction signal according to the target parameter, the base station may multiply the target parameter by the target prediction signal to obtain the nonlinear distortion prediction signal.

In the above embodiment, the base station can predict and calculate the nonlinear distortion signal generated when the subsequent signal passes through the nonlinear component based on the nonlinear distortion signal caused by the nonlinear component, which can improve the accuracy of the determined nonlinear distortion prediction signal Further, the useful signal can be pre-distorted according to the determined nonlinear distortion prediction signal, so as to realize the correction of the nonlinear distortion problem caused by the nonlinear components and improve the accuracy of nonlinear distortion correction.

When the nonlinear signal processing method provided in the embodiment of the present application is applied to the central station, reference may be made to the implementation manner when the method is applied to the base station, which will not be repeated here.

Based on the above embodiments and the same idea, an embodiment of the present application also provides a device, the device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory , realizing the nonlinear signal processing method shown in FIG. 16 above.

Based on the above embodiments and the same idea, this embodiment of the present application also provides a chip, the chip may include the components or modules included in the base station in the first embodiment above; or the chip may include the components or modules in the second embodiment above The components or modules included in the base station; or the chip may include the components or modules included in the central station in the second embodiment above; or the chip may include the components included in the central station in the third embodiment above or modules.

Based on the above embodiments and the same idea, the embodiments of the present application also provide a communication system, the communication system at least includes: the base station provided in the first embodiment above, or the base station and the central station provided in the second embodiment above, Or the central station provided in the third embodiment above.

Apparently, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

A base station, characterized by comprising: a plurality of radio frequency links, an optical module, and a feature calculation module; wherein, the number of the plurality of radio frequency links is greater than or equal to 2;

Each radio frequency link is used to receive one signal of a corresponding frequency band through the antenna, and after performing radio frequency processing on the one signal, send the one signal to the optical module;

The optical module is configured to perform electro-optical conversion processing on the multi-channel signals from the multiple radio frequency links to obtain an optical signal including the processed multi-channel signals; wherein the optical module includes a nonlinear element A device, wherein there are a first radio frequency link and at least one second radio frequency link among the plurality of radio frequency links, and a signal of the at least one second radio frequency link generates a nonlinear distorted signal after passing through the nonlinear component, The frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link, and the optical signal also includes the nonlinear distortion signal; the optical signal is sent to the central station, and the performing photoelectric conversion processing on the optical signal to obtain an electrical signal and sending the electrical signal to the feature calculation module;

Each second radio frequency link is also used to send the obtained signal to the feature calculation module after performing radio frequency processing on the received signal of the corresponding frequency band;

The feature calculation module is configured to extract a target signal from the electrical signal from the optical module; wherein the target signal includes a signal of a frequency band corresponding to the first radio frequency link included in the electrical signal ; calculate a nonlinear distortion prediction signal according to the target signal and at least one signal from the at least one second radio frequency link, and send the nonlinear distortion prediction signal to the first radio frequency link, wherein the The nonlinear distortion prediction signal is the first prediction signal of the nonlinear distortion signal;

The first radio frequency link is further configured to perform predistortion processing and radio frequency processing on signals in the frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, and send the processed signal to the optical module .
The base station according to claim 1, wherein the starting frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency, wherein:

When there is a second radio frequency link in the plurality of radio frequency links, the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, and the second frequency is the Twice the cut-off frequency of the corresponding frequency band of a second radio frequency link; or

When there are two second radio frequency links in the plurality of radio frequency links, the first frequency is the sum of the starting frequencies of the corresponding frequency bands of the two second radio frequency links, and the second frequency is the The sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the difference between the start frequencies of the frequency bands corresponding to the two second radio frequency links, and the second frequency is the The difference between the cutoff frequencies of the corresponding frequency bands of the two second radio frequency links.
The base station according to claim 1 or 2, wherein the feature calculation module includes an iterative calculation module, and the iterative calculation module is used for:

calculating a target parameter according to the target signal, wherein the target parameter is used to characterize the nonlinear distortion characteristics of the nonlinear component;

calculating a target prediction signal according to at least one signal of the at least one second radio frequency link, wherein the target prediction signal is a second prediction signal of the nonlinear distortion signal;

Correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal.
The base station according to claim 3, wherein the iterative calculation module, when calculating the target parameter according to the target signal, is specifically used for:

Calculate the target parameters according to the set first calculation model and the target signal, wherein the first calculation model is used to represent one signal among the multiple signals input to the nonlinear component, the nonlinear element The corresponding relationship between the nonlinear distortion signal output by the device and the same frequency band as the one signal and the nonlinear distortion characteristic parameters of the nonlinear component;

When the iterative calculation module calculates the target prediction signal according to at least one signal of the at least one second radio frequency link, it is specifically used for:

Calculate the target prediction signal according to the set second calculation model and at least one signal of the at least one second radio frequency link, wherein the second calculation model is used to represent at least one signal passing through the nonlinear component Correspondence between the at least one signal and the nonlinear distortion signal generated after the at least one signal passes through the nonlinear component.
The base station according to claim 3 or 4, wherein the iterative calculation module, when correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal, is specifically used for:

The target parameter is multiplied by the target prediction signal to obtain the nonlinear distortion prediction signal.
The base station according to any one of claims 1-5, wherein the optical module comprises: an electro-optical conversion module, a photoelectric conversion module, a first port, a second port, and a third port;

The electro-optical conversion module is used to perform electro-optical conversion processing on the multi-channel signal, and the electro-optic conversion module includes the nonlinear components;

The photoelectric conversion module is used to perform photoelectric conversion processing on the optical signal;

The first port is used to receive the multi-channel signal;

the second port for sending the optical signal to the central station;

The third port is configured to send the electrical signal to the feature calculation module.
The base station according to any one of claims 1-6, wherein the feature calculation module further includes a filtering module;

The filtering module is configured to filter the electrical signal to obtain the target signal.
The base station according to any one of claims 1-7, wherein the feature calculation module further includes a feedback module, and the feedback module is used for:

Perform delay correction processing on the target signal and at least one signal of the at least one second radio frequency link to obtain the target signal and at least one signal of the at least one second radio frequency link with consistent time delays.
The base station according to claim 8, wherein the feedback module comprises: a lock module, a correlator, a threshold judgment module, a delay calculation module, and a delay alignment module;

The locking module is configured to respectively latch signals with a set time slot length from the at least one second radio frequency link, and send the latched signals to the correlator;

The correlator is configured to perform correlation processing on the target signal and the signal from the lock module to obtain a correlation signal, and send the correlation signal to the threshold judgment module, wherein the correlation signal is non-linear signal;

The threshold judgment module is used to judge whether the correlation value of the received correlation signal is greater than or equal to a set value, and if so, send the correlation signal to the delay calculation module, otherwise, do not signal processing;

The delay calculation module is configured to calculate the signal of the first radio frequency link and the at least one second radio frequency link according to the correlation signal when receiving the correlation signal from the threshold judgment module The time delay between the signals of the set time slot length, and sending the time delay to the time delay alignment module;

The delay alignment module is configured to, after receiving the delay from the delay calculation module, remove the setting between the target signal and the at least one second radio frequency link according to the delay. Signals with the time delay in the signals with a fixed slot length, and removing the signals with the time delay with the target signal among the signals with a set time slot length in each second radio frequency link.
The base station according to claim 9, wherein the threshold judgment module is also used for:

When it is determined that the correlation value of the related signal is greater than or equal to the set value, instruct the lock module to respectively lock the signal of the set time slot length from the at least one second radio frequency link, and use the current The latched signal replaces the previously latched signal;

When it is determined that the correlation value of the correlation signal is smaller than the set value, instruct the lock module to stop latching the signal of the set time slot length from the at least one second radio frequency link.
A base station, characterized by comprising: a plurality of radio frequency links, an optical module, and a feature calculation module; wherein, the number of the plurality of radio frequency links is greater than or equal to 2;

Each radio frequency link is used to receive one signal of a corresponding frequency band through the antenna, and after performing radio frequency processing on the one signal, send the one signal to the optical module;

The optical module is configured to perform electro-optical conversion processing on the multi-channel signals from the multiple radio frequency links to obtain an optical signal including the processed multi-channel signals; wherein the optical module includes a nonlinear element A device, wherein there are a first radio frequency link and at least one second radio frequency link among the plurality of radio frequency links, and a signal of the at least one second radio frequency link generates a nonlinear distorted signal after passing through the nonlinear component, The frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link, and the optical signal also includes the nonlinear distortion signal; sending the optical signal to the central station, receiving performing photoelectric conversion processing on the target signal from the central station, and sending the processed target signal to the feature calculation module, wherein the target signal includes the first radio frequency link The signal of the corresponding frequency band;

Each second radio frequency link is also used to send the obtained signal to the feature calculation module after performing radio frequency processing on the received signal of the corresponding frequency band;

The feature calculation module is configured to receive the target signal from the optical module; calculate a nonlinear distortion prediction signal according to the target signal and at least one signal from the at least one second radio frequency link, and calculate the The nonlinear distortion prediction signal is sent to the first radio frequency link, wherein the nonlinear distortion prediction signal is a first prediction signal of the nonlinear distortion signal;

The first radio frequency link is further configured to perform predistortion processing and radio frequency processing on signals in the frequency band corresponding to the first radio frequency link according to the nonlinear distortion prediction signal, and send the processed signal to the optical module .
The base station according to claim 11, wherein the feature calculation module includes an iterative calculation module, and the iterative calculation module is used for:

calculating a target parameter according to the target signal, wherein the target parameter is used to characterize the nonlinear distortion characteristics of the nonlinear component;

calculating a target prediction signal according to at least one signal of the at least one second radio frequency link, wherein the target prediction signal is a second prediction signal of the nonlinear distortion signal;

Correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal.
The base station according to claim 11 or 12, wherein the feature calculation module further includes a filtering module;

The filtering module is configured to filter the electrical signal to obtain the target signal.
The base station according to any one of claims 11-13, wherein the optical module receives the target signal from the central station, performs photoelectric conversion processing on the target signal, and converts the processed When the target signal is sent to the feature calculation module, it is specifically used for:

receiving a downlink signal from the central station, performing photoelectric conversion processing on the downlink signal, and sending the processed downlink signal to the feature calculation module, wherein the downlink signal includes the target signal and other signals to be sent to the base station;

The feature calculation module, when receiving the target signal from the optical module, is specifically used for:

receiving the downlink signal from the optical module, and filtering the downlink signal to obtain the target signal.
The base station according to any one of claims 11-14, wherein the feature calculation module further includes a feedback module, and the feedback module is used for:

Perform delay correction processing on the target signal and at least one signal of the at least one second radio frequency link to obtain the target signal and at least one signal of the at least one second radio frequency link with consistent time delays.
The base station according to claim 15, wherein the feedback module comprises: a lock module, a correlator, a threshold judgment module, a delay calculation module, and a delay alignment module;

The locking module is configured to respectively latch signals with a set time slot length from the at least one second radio frequency link, and send the latched signals to the correlator;

The correlator is configured to perform correlation processing on the target signal and the signal from the lock module to obtain a correlation signal, and send the correlation signal to the threshold judgment module, wherein the correlation signal is non-linear signal;

The threshold judgment module is used to judge whether the correlation value of the received correlation signal is greater than or equal to a set value, and if so, send the correlation signal to the delay calculation module, otherwise, do not signal processing;

The delay calculation module is configured to calculate the signal of the first radio frequency link and the at least one second radio frequency link according to the correlation signal when receiving the correlation signal from the threshold judgment module The time delay between the signals of the set time slot length, and sending the time delay to the time delay alignment module;

The delay alignment module is configured to, after receiving the delay from the delay calculation module, remove the setting between the target signal and the at least one second radio frequency link according to the delay. Signals with the time delay in the signals with a fixed slot length, and removing the signals with the time delay with the target signal among the signals with a set time slot length in each second radio frequency link.
The base station according to claim 16, wherein the threshold judgment module is also used for:

When it is determined that the correlation value of the related signal is greater than or equal to the set value, instruct the lock module to respectively lock the signal of the set time slot length from the at least one second radio frequency link, and use the current The latched signal replaces the previously latched signal;

When it is determined that the correlation value of the correlation signal is smaller than the set value, instruct the lock module to stop latching the signal of the set time slot length from the at least one second radio frequency link.
A central station, characterized in that it includes: an optical module, a signal processing module;

The optical module is configured to perform photoelectric conversion processing on the optical signal to obtain an electrical signal after receiving the optical signal from the base station, and send the electrical signal to the signal processing module; wherein the electrical signal contains a nonlinear Distorted signals, multiple signals received by multiple radio frequency links of the base station through antennas, the number of the multiple radio frequency links is greater than or equal to 2, and the first radio frequency link and the first radio frequency link exist in the multiple radio frequency links At least one second radio frequency link, the base station includes nonlinear components, and the signal of the at least one second radio frequency link passes through the nonlinear components to generate the nonlinear distortion signal, and the nonlinear distortion The frequency band of the signal overlaps with the frequency band corresponding to the first radio frequency link;

The signal processing module is configured to receive the electrical signal from the optical module, extract the target signal of the frequency band corresponding to the first radio frequency link from the electrical signal, and send the target signal to the The optical module;

The optical module is further configured to perform electro-optical conversion processing on the target signal, and send the processed target signal to the base station.
The central station according to claim 18, wherein the starting frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency, wherein:

When there is a second radio frequency link in the plurality of radio frequency links, the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, and the second frequency is the Twice the cut-off frequency of the corresponding frequency band of a second radio frequency link; or

When there are two second radio frequency links in the plurality of radio frequency links, the first frequency is the sum of the starting frequencies of the corresponding frequency bands of the two second radio frequency links, and the second frequency is the The sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the difference between the start frequencies of the frequency bands corresponding to the two second radio frequency links, and the second frequency is the The difference between the cutoff frequencies of the corresponding frequency bands of the two second radio frequency links.
The central station according to claim 19, characterized in that,

The signal processing module includes a filtering module, the filtering module is used to receive the electrical signal from the optical module, filter the electrical signal, and obtain the target signal;

When the optical module performs electro-optical conversion processing on the target signal, and sends the processed target signal to the base station, it is specifically used to: perform the target signal and other signals to be sent to the base station Electro-optical conversion processing, obtaining a downlink signal including the target signal and other signals to be sent to the base station, and sending the downlink signal to the base station.
A central station, characterized in that it includes: an optical module, a signal processing module, and a feature calculation module;

The optical module is configured to receive an optical signal from at least one base station, perform photoelectric conversion processing on the optical signal of each base station in the at least one base station, and obtain an electrical signal of each base station; wherein, the electrical signal of any one base station Including non-linear distortion signals, multiple signals received by multiple radio frequency links of the base station through the antenna, the number of the multiple radio frequency links is greater than or equal to 2, and there is a first radio frequency link among the multiple radio frequency links A radio frequency link and at least one second radio frequency link, the base station includes nonlinear components, and the signal of the at least one second radio frequency link passes through the nonlinear components to generate the nonlinear distortion signal, so The frequency band of the nonlinear distortion signal overlaps with the frequency band corresponding to the first radio frequency link; sending the electrical signal of each base station to the signal processing module and the feature calculation module respectively;

The feature calculation module is used to respectively receive the electrical signal from each base station of the optical module; respectively perform feature calculation processing on the electrical signal of each base station to obtain a nonlinear distortion prediction signal corresponding to each base station, and respectively The nonlinear distortion prediction signal corresponding to each base station is sent to the signal processing module; wherein, the feature calculation processing on the electrical signal of any base station includes the following steps: extracting the first radio frequency chain from the electrical signal target signal in a corresponding frequency band, and at least one signal from the at least one second radio frequency link is respectively extracted from the electrical signal; according to the target signal and at least one signal of the at least one second radio frequency link Calculating the nonlinear distortion prediction signal with one signal, wherein the nonlinear distortion prediction signal is the first prediction signal of the nonlinear distortion signal;

The signal processing module is configured to respectively receive electrical signals from each base station of the optical module; perform radio frequency processing on the electrical signals of the at least one base station to obtain a target combining signal; wherein, the target combining signal includes The signal of the frequency band corresponding to the first radio frequency link; respectively receive the nonlinear distortion prediction signal corresponding to each base station from the feature calculation module; The channel signal is processed for distortion correction.
The central station according to claim 21, wherein the start frequency of the nonlinear distortion signal is greater than or equal to the first frequency, and the cutoff frequency of the nonlinear distortion signal is less than or equal to the second frequency, wherein:

When there is a second radio frequency link in the plurality of radio frequency links, the first frequency is twice the starting frequency of the frequency band corresponding to the second radio frequency link, and the second frequency is the Twice the cut-off frequency of the corresponding frequency band of a second radio frequency link; or

When there are two second radio frequency links in the plurality of radio frequency links, the first frequency is the sum of the starting frequencies of the corresponding frequency bands of the two second radio frequency links, and the second frequency is the The sum of the cutoff frequencies of the frequency bands corresponding to the two second radio frequency links; or, the first frequency is the difference between the start frequencies of the frequency bands corresponding to the two second radio frequency links, and the second frequency is the The difference between the cutoff frequencies of the corresponding frequency bands of the two second radio frequency links.
The central station according to claim 21 or 22, wherein the characteristic calculation module includes an iterative calculation module, and the iterative calculation module is used for:

calculating a target parameter according to the target signal, wherein the target parameter is used to characterize the nonlinear distortion characteristics of the nonlinear component;

calculating a target prediction signal according to at least one signal from the at least one second radio frequency link, wherein the target prediction signal is a second prediction signal of the nonlinear distortion signal;

Correcting the target prediction signal according to the target parameter to obtain the nonlinear distortion prediction signal.
The central station according to claim 23, wherein the iterative calculation module, when calculating the target parameter according to the target signal, is specifically used for:

Calculate the target parameters according to the set first calculation model and the target signal, wherein the first calculation model is used to represent one signal among the multiple signals input to the nonlinear component, the nonlinear element The corresponding relationship between the nonlinear distortion signal output by the device and the same frequency band as the one signal and the nonlinear distortion characteristic parameters of the nonlinear component;

When the iterative calculation module calculates the target prediction signal according to at least one signal of the at least one second radio frequency link, it is specifically used for:

Calculate the target prediction signal according to the set second calculation model and at least one signal of the at least one second radio frequency link, wherein the second calculation model is used to represent at least one signal passing through the nonlinear component Correspondence between the at least one signal and the nonlinear distortion signal generated after the at least one signal passes through the nonlinear component.
The central station according to claim 23 or 24, wherein the iterative calculation module, when correcting the target prediction signal according to the target parameters to obtain the nonlinear distortion prediction signal, is specifically used for :

The target parameter is multiplied by the target prediction signal to obtain the nonlinear distortion prediction signal.
The central station according to any one of claims 21-25, wherein the feature calculation module further includes a filtering module;

The filtering module is configured to filter the combined electrical signal to obtain the target signal.
The central station according to any one of claims 21-26, wherein the feature calculation module further includes a feedback module, and the feedback module is used for:

Perform delay correction processing on the target signal and at least one signal of the at least one second radio frequency link to obtain the target signal and at least one signal of the at least one second radio frequency link with consistent time delays.
The central station according to claim 27, wherein the feedback module comprises: a lock module, a correlator, a threshold judgment module, a time delay calculation module, and a time delay alignment module;

The locking module is configured to respectively latch signals with a set time slot length from the at least one second radio frequency link, and send the latched signals to the correlator;

The correlator is configured to perform correlation processing on the target signal and the signal from the lock module to obtain a correlation signal, and send the correlation signal to the threshold judgment module, wherein the correlation signal is non-linear signal;

The threshold judgment module is used to judge whether the correlation value of the received correlation signal is greater than or equal to a set value, and if so, send the correlation signal to the delay calculation module, otherwise, do not signal processing;

The delay calculation module is configured to calculate the signal of the first radio frequency link and the at least one second radio frequency link according to the correlation signal when receiving the correlation signal from the threshold judgment module The time delay between the signals of the set time slot length, and sending the time delay to the time delay alignment module;

The delay alignment module is configured to, after receiving the delay from the delay calculation module, remove the setting between the target signal and the at least one second radio frequency link according to the delay. Signals with the time delay in the signals with a fixed slot length, and removing the signals with the time delay with the target signal among the signals with a set time slot length in each second radio frequency link.
The central station according to claim 28, wherein the threshold judgment module is also used for:

When it is determined that the correlation value of the related signal is greater than or equal to the set value, instruct the lock module to respectively lock the signal of the set time slot length from the at least one second radio frequency link, and use the current The latched signal replaces the previously latched signal;

When it is determined that the correlation value of the correlation signal is smaller than the set value, instruct the lock module to stop latching the signal of the set time slot length from the at least one second radio frequency link.
A communication system, characterized in that it includes:

The base station according to any one of claims 1-10; or

The base station according to any one of claims 11-17, and the central station according to any one of claims 18-20; or

The central station according to any one of claims 21-29.