A communication signal adaptive demodulation method and system for non-cooperative communication mode

Abstract

The invention provides a communication signal adaptive demodulation method and system in a non-cooperative communication mode, belongs to the technical field of communication signal modulation and demodulation, and solves the problem that the signal blind demodulation quality and parameter estimation accuracy are low under the condition of uncertain signal structure parameters; the invention realizes burst signal detection, separation and data splicing in a burst signal detection module; obtains signal characteristics such as signal modulation style and signal parameters and new signal discrimination in a modulation identification and parameter estimation module, and generates a signal parameter library; in a signal demodulation module, carrier synchronization, timing synchronization and symbol judgment are completed according to signal characteristic parameters, signal demodulation is realized, and a demodulation result is output; in a demodulation quality assessment module, the demodulation result is dynamically evaluated, the demodulation parameters are adjusted, and the signal parameter library is updated; the invention forms a whole communication signal adaptive demodulation feedback link, and can effectively improve the signal blind demodulation quality and parameter estimation accuracy in a non-cooperative communication mode.

Description

Technical Field

[0001] The present invention belongs to the technical field of communication signal modulation and demodulation, is applied to non-cooperative communication modes, and specifically relates to a communication signal adaptive demodulation method and system for non-cooperative communication modes. Background Art

[0002] In a non-cooperative communication mode, a third party cannot participate in the communication dialogue process. Therefore, the third party usually needs to perform blind processing on the communication signal and estimate the signal modulation style, code rate, frequency interval and other parameters based on the signal characteristics for signal demodulation. In the prior art, due to the channel conditions or the accuracy of the estimation algorithm, there is a deviation between the estimated parameters and the actual parameters, which will affect the output result of the signal demodulation. Therefore, how to improve the blind demodulation quality and parameter estimation accuracy of the communication signal when the structure and parameters of the communication signal are uncertain, so as to realize the adaptive demodulation process of the communication signal in the non-cooperative communication mode, has become a problem that researchers in this field need to solve urgently. Summary of the invention

[0003] The present invention provides an adaptive demodulation method for communication signals, the purpose of which is to realize the entire feedback control link of burst signal detection, modulation style recognition, parameter estimation, signal demodulation and demodulation quality assessment, and dynamic parameter adjustment in scenarios with uncertain signal structure and parameters in non-cooperative communication modes, and ultimately effectively improve the blind demodulation quality of communication signals and the accuracy of parameter estimation in non-cooperative communication modes.

[0004] The present invention adopts the following technical solutions to achieve the purpose:

[0005] A communication signal adaptive demodulation method in a non-cooperative communication mode comprises the following steps:

[0006] S1, read the data frame to be demodulated of the communication signal, determine whether there is a burst signal in the data frame to be demodulated, and if so, estimate the start and end time of the burst signal and splice the burst signal across frames to obtain a burst signal data stream;

[0007] S2. Identify the burst signal modulation type and estimate the burst signal characteristic parameters according to the burst signal data stream;

[0008] S3, comparing the modulation type and characteristic parameters of the burst signal with the signal data in the signal parameter library. If the comparison is successful, reading the corresponding signal demodulation parameters from the signal parameter library, demodulating the burst signal, and outputting the demodulation result;

[0009] S4. Calculate the EVM vector of the demodulation result, compare it with the theoretical signal-to-noise ratio-EVM curve under the burst signal modulation type, obtain the EVM vector deviation value, and modify the modulation style and update the signal parameter library based on the comparison result of the EVM vector deviation value and the preset threshold.

[0010] Preferably, before step S1, the method further includes step S0 of importing a signal knowledge accumulation library, wherein the signal knowledge accumulation library contains discrete data tables of theoretical signal-to-noise ratio-EVM curves under various modulation types.

[0011] Furthermore, in step S1, if there is no burst signal in the data frame to be demodulated, it is a continuous signal, and the signal demodulation parameters corresponding to the continuous signal are read from the signal parameter library, the continuous signal is demodulated by blind synchronization and estimation, and the demodulation result is output, and step S4 is entered.

[0012] Furthermore, in step S3, if the modulation type and characteristic parameters of the burst signal are not successfully compared with the signal data in the signal parameter library, the burst signal is a new signal, and the modulation type and characteristic parameters of the new signal are written into the signal parameter library as the signal data of the new signal. The new signal is blindly synchronized and estimated and demodulated according to the signal demodulation parameters of the signal parameter library in a manner consistent with the continuous signal, and the demodulation result is output.

[0013] Furthermore, in step S4, the preset threshold includes a first-level threshold and a second-level threshold; if the EVM vector deviation value exceeds the first-level threshold, the corresponding modulation style is modified; if the EVM vector deviation value is between the first-level threshold and the second-level threshold, the symbol rate or frequency interval is adjusted, and the signal parameter library is updated for the data demodulation process of the next frame of data to be demodulated; if the EVM vector deviation value is lower than the second-level threshold and the deviation value is in a convergence state, it is considered that the demodulation result meets the requirements.

[0014] The present invention also provides a communication signal adaptive demodulation system in a non-cooperative communication mode, comprising a burst signal detection module, a modulation identification and parameter estimation module, a signal demodulation module and a demodulation quality assessment module; the burst signal detection module is used for burst signal detection, separation and data splicing; the modulation identification and parameter estimation module is used for obtaining the modulation type and characteristic parameters of the signal to be demodulated, and performing new signal discrimination; the signal demodulation module is used for implementing a signal demodulation process and outputting a demodulation result according to the modulation type and characteristic parameters of the signal to be demodulated; the demodulation quality assessment module is used for evaluating the quality of the demodulation result and feeding back the demodulation parameters by calculating the EVM vector deviation value.

[0015] Furthermore, the burst signal detection module is used to detect communication signals and burst signals in communication signals, obtain the start and end time of the burst signal, and separate the burst signal data according to the duration and sampling rate; it is also used to perform cross-frame splicing of burst signals that do not end in the current data frame.

[0016] Furthermore, the modulation identification and parameter estimation module is used to estimate the modulation type and characteristic parameters of the signal to be demodulated, and the characteristic parameters include signal code rate, frequency interval and signal-to-noise ratio; it is also used to identify new signals, and when the signal to be demodulated is identified as a new signal, the modulation type and characteristic parameters of the new signal are written into the signal parameter library as signal data of the new signal.

[0017] Furthermore, the signal demodulation module is used to obtain corresponding signal demodulation parameters through a signal parameter library for demodulation; the signal demodulation module includes a burst signal demodulation component and a continuous signal demodulation component; the burst signal demodulation component is used to capture, synchronize and judge the burst signal through known parameters when the synchronization header and channel probe information of the burst signal match the signal knowledge accumulation database; the continuous signal demodulation component is used to read the signal demodulation parameters of the corresponding continuous signal from the signal parameter library, and demodulate the continuous signal for blind synchronization and estimation.

[0018] Furthermore, the demodulation quality assessment module includes a preset threshold component, which is used to set a first-level threshold and a second-level threshold; the demodulation quality assessment module is used to calculate the EVM vector of the demodulation result, and compare it with the theoretical signal-to-noise ratio-EVM curve in the signal knowledge accumulation database to obtain an EVM vector deviation value; it is also used to compare the calculated EVM vector deviation value with the preset threshold, and based on the comparison result, modify the modulation style and update the signal parameter library.

[0019] In summary, due to the adoption of this technical solution, the beneficial effects of the present invention are as follows:

[0020] The present invention proposes a method for adaptive demodulation of communication signals in a non-cooperative communication mode, and a corresponding system structure, which realizes blind demodulation of communication signals with uncertain signal structures and parameters, and the entire feedback closed-loop control of burst signal detection, modulation recognition, parameter estimation, demodulation, demodulation quality assessment, and dynamic adjustment of signal parameters, thereby effectively improving the blind demodulation quality of communication signals in the non-cooperative communication mode and improving the accuracy of estimated parameters; therefore, the method and system of the present invention solve the problem of low signal blind demodulation quality and low parameter estimation accuracy when the communication signal structure parameters are uncertain. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the steps of the method of the present invention;

[0022] Figure 2 A partial flow chart of the adaptive demodulation process of the method of the present invention;

[0023] Figure 3 It is another part of the flow chart of the adaptive demodulation process of the method of the present invention;

[0024] Figure 4 It is a structural block diagram of the composition of the system of the present invention;

[0025] Figure 5 It is a component block diagram of each module in the system of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] like Figure 1 FIG. 1 is a method for adaptively demodulating communication signals in a non-cooperative communication mode. For a detailed description of each step in this embodiment, please also refer to FIG. Figure 2 The process diagram of the method includes the following steps:

[0030] S0. Import a signal knowledge accumulation library, which contains discrete data tables of theoretical signal-to-noise ratio-EVM curves under various modulation types.

[0031] S1. Read the data frame to be demodulated of the communication signal, and determine whether there is a burst signal in the data frame to be demodulated. If so, estimate the start and end time of the burst signal and splice the burst signal across frames to obtain a burst signal data stream.

[0032] In this step, it is first determined whether the data frame contains a communication signal. If not, the process of reading the data frame is repeated; if contained, the data frame to be demodulated of the communication signal is read.

[0033] At the same time, if there is no burst signal in the data frame to be demodulated, it is a continuous signal. The signal demodulation parameters corresponding to the continuous signal are read from the signal parameter library, the continuous signal is blindly synchronized and estimated and demodulated, the demodulation result is output, and the subsequent step S4 in this embodiment is entered.

[0034] S2. According to the burst signal data stream obtained in step S1, identify the burst signal modulation type and estimate the burst signal characteristic parameters.

[0035] In this step, the burst signal characteristic parameters are estimated, including code rate, signal bandwidth and signal-to-noise ratio parameters.

[0036] S3. Compare the modulation type and characteristic parameters of the burst signal with the signal data in the signal parameter library. If the comparison is successful, read the corresponding signal demodulation parameters from the signal parameter library, demodulate the burst signal, and output the demodulation result.

[0037] In this step, if the signal parameters of the burst signal do not belong to the existing signal type in the signal parameter library after comparison with the signal parameter library, that is, the comparison is unsuccessful, then the burst signal is treated as a new signal, and the modulation type and characteristic parameters of the new signal are written into the signal parameter library as the signal data of the new signal.

[0038] The process of demodulating the burst signal in this step and the process of demodulating the continuous signal mentioned in step S1 can be specifically described as follows: when the signal structure of the burst signal such as the synchronization header and the channel probe matches the data in the signal knowledge accumulation library, the signal can be captured, synchronized and judged through known parameters; on the contrary, if it does not match, it is consistent with the continuous signal, and the burst signal is blindly synchronized and estimated and demodulated according to the parameters of the signal parameter library, and the demodulation result is output.

[0039] S4. Calculate the EVM vector of the demodulation result, compare it with the theoretical signal-to-noise ratio-EVM curve under the burst signal modulation type, obtain the EVM vector deviation value, and modify the modulation style and update the signal parameter library based on the comparison result of the EVM vector deviation value and the preset threshold.

[0040] In this step, the preset thresholds include a primary threshold and a secondary threshold; if the EVM vector deviation value exceeds the primary threshold, the corresponding modulation style is modified; if the EVM vector deviation value is between the primary threshold and the secondary threshold, the symbol rate or frequency interval is adjusted, and the signal parameter library is updated for the data demodulation process of the next frame of data to be demodulated; if the EVM vector deviation value is lower than the secondary threshold and the deviation value is in a convergence state, it is considered that the quality of the demodulation output result has met the requirements under the modulation style and signal-to-noise ratio conditions.

[0041] Example 2

[0042] like Figure 3 As shown, this embodiment specifically introduces a communication signal adaptive demodulation system of a non-cooperative communication mode, which includes 4 main structures, namely a burst signal detection module, a modulation identification and parameter estimation module, a signal demodulation module and a demodulation quality assessment module. Among them, the burst signal detection module is used for burst signal detection, separation and data splicing; the modulation identification and parameter estimation module is used to identify the modulation type of the signal to be demodulated, estimate the characteristic parameters of the signal to be demodulated, and perform new signal discrimination, and also store the signal parameters in the signal parameter library; the signal demodulation module is used to implement the signal demodulation process according to the modulation type and characteristic parameters of the signal to be demodulated, and output the demodulation result. The specific functions are burst signal demodulation and continuous signal demodulation; the demodulation quality assessment module is used to evaluate the quality of the demodulation result and feedback the demodulation parameters by calculating the EVM vector deviation value, so as to realize the evaluation of the demodulation quality and make reasonable parameter adjustments.

[0043] The detailed description of each module is as follows, which can also be referred to Figure 4 .

[0044] The burst signal detection module has the following specific functions: signal detection, burst signal detection, burst start and end time acquisition, and signal data splicing; it is used to detect communication signals and burst signals in communication signals, obtain the start and end time of burst signals, and separate burst signal data according to duration and sampling rate; it is also used to perform cross-frame splicing of burst signals that do not end in the current data frame.

[0045] The modulation identification and parameter estimation module has the following specific functions: modulation identification, parameter estimation and new signal identification. It is used to estimate the modulation type and characteristic parameters of the signal to be demodulated, and the characteristic parameters include signal bandwidth, signal code rate, frequency interval and signal-to-noise ratio. It is also used to identify new signals, and to determine whether the current signal is a new signal that does not exist in the signal parameter library based on the aforementioned characteristic parameters. When the signal to be demodulated is determined to be a new signal, the modulation type and characteristic parameters of the new signal are written into the signal parameter library as the signal data of the new signal.

[0046] The signal demodulation module is used to obtain the corresponding signal demodulation parameters through the signal parameter library for demodulation; the signal demodulation module includes a burst signal demodulation component and a continuous signal demodulation component; the burst signal demodulation component includes a synchronization header acquisition and comparison function. If the signal knowledge accumulation library contains the parameters of the burst signal, the burst signal can be captured, synchronized, and processed by obtaining its synchronization header. Therefore, when the synchronization header and channel probe information of the burst signal match the signal knowledge accumulation database, the burst signal is captured, synchronized, and judged by known parameters; the continuous signal demodulation component is used to read the signal demodulation parameters of the corresponding continuous signal from the signal parameter library and demodulate the continuous signal for blind synchronization and estimation.

[0047] The demodulation quality assessment module has the functions of demodulation quality assessment and parameter adjustment; it includes a preset threshold component, which is used to set a primary threshold and a secondary threshold; the demodulation quality assessment module is used to calculate the EVM vector of the demodulation result, and after comparing it with the theoretical signal-to-noise ratio-EVM curve in the signal knowledge accumulation database, calculate the EVM vector deviation value to realize the demodulation quality assessment process; it is also used to compare the calculated EVM vector deviation value with a two-level threshold, and according to the comparison result, modify the modulation style and dynamically adjust the signal parameters, and update the signal parameter library at the same time; the process of dynamically adjusting the signal parameters is: if the EVM vector deviation value exceeds the primary threshold, modify the corresponding modulation style; if the EVM vector deviation value is between the primary threshold and the secondary threshold, adjust the symbol rate or frequency interval, and update the signal parameter library for the data demodulation process of the next frame of data to be demodulated; if the EVM vector deviation value is lower than the secondary threshold and the deviation value is in a convergence state, it is considered that the demodulation result meets the requirements and the current demodulation parameters are maintained.

Claims

1. A communication signal adaptive demodulation method in a non-cooperative communication mode, characterized in that: The steps include: S1, read the data frame to be demodulated of the communication signal, determine whether there is a burst signal in the data frame to be demodulated, and if so, estimate the start and end time of the burst signal and splice the burst signal across frames to obtain a burst signal data stream; S2. Identify the burst signal modulation type and estimate the burst signal characteristic parameters according to the burst signal data stream; S3, comparing the modulation type and characteristic parameters of the burst signal with the signal data in the signal parameter library. If the comparison is successful, reading the corresponding signal demodulation parameters from the signal parameter library, demodulating the burst signal, and outputting the demodulation result; S4, calculating the EVM vector of the demodulation result, comparing it with the theoretical signal-to-noise ratio-EVM curve under the burst signal modulation type, obtaining the EVM vector deviation value, and modifying the modulation style and updating the signal parameter library according to the comparison result between the EVM vector deviation value and the preset threshold value; In step S4, the preset threshold includes a primary threshold and a secondary threshold; If the EVM vector deviation value exceeds the first-level threshold, the corresponding modulation mode is modified; If the EVM vector deviation value is between the first-level threshold and the second-level threshold, the symbol rate or frequency interval is adjusted, and the signal parameter library is updated for the data demodulation process of the next frame of data to be demodulated; if the EVM vector deviation value is lower than the second-level threshold and the deviation value is in a convergence state, it is considered that the demodulation result meets the requirements.

2. The method for adaptive demodulation of communication signals in a non-cooperative communication mode according to claim 1, characterized in that: Before step S1, the method further includes step S0, importing a signal knowledge accumulation library, wherein the signal knowledge accumulation library contains discrete data tables of theoretical signal-to-noise ratio-EVM curves under various modulation types.

3. The method for adaptive demodulation of communication signals in a non-cooperative communication mode according to claim 1, characterized in that: In step S1, if there is no burst signal in the data frame to be demodulated, it is a continuous signal. The signal demodulation parameters corresponding to the continuous signal are read from the signal parameter library, the continuous signal is demodulated by blind synchronization and estimation, the demodulation result is output, and step S4 is entered.

4. The method for adaptive demodulation of communication signals in a non-cooperative communication mode according to claim 1, characterized in that: In step S3, if the modulation type and characteristic parameters of the burst signal are not successfully compared with the signal data in the signal parameter library, the burst signal is a new signal, and the modulation type and characteristic parameters of the new signal are written into the signal parameter library as the signal data of the new signal. The new signal is blindly synchronized and estimated and demodulated according to the signal demodulation parameters in the signal parameter library in a manner consistent with the continuous signal, and the demodulation result is output.

5. A communication signal adaptive demodulation system in a non-cooperative communication mode, characterized in that: It includes a burst signal detection module, a modulation identification and parameter estimation module, a signal demodulation module and a demodulation quality assessment module; the burst signal detection module is used for burst signal detection, separation and data splicing; The modulation identification and parameter estimation module is used to obtain the modulation type and characteristic parameters of the signal to be demodulated and to identify the new signal; the signal demodulation module is used to implement the signal demodulation process according to the modulation type and characteristic parameters of the signal to be demodulated and output the demodulation result; the demodulation quality assessment module is used to evaluate the quality of the demodulation result and feedback the demodulation parameters by calculating the EVM vector deviation value; The demodulation quality assessment module includes a preset threshold component, and the preset threshold component is used to set a primary threshold and a secondary threshold; The demodulation quality assessment module is used to calculate the EVM vector of the demodulation result and compare it with the theoretical signal-to-noise ratio-EVM curve in the signal knowledge accumulation database to obtain the EVM vector deviation value; it is also used to compare the calculated EVM vector deviation value with the preset threshold, and based on the comparison result, modify the modulation style and update the signal parameter library.

6. The communication signal adaptive demodulation system of a non-cooperative communication mode according to claim 5, characterized in that: The burst signal detection module is used to detect communication signals and burst signals in communication signals, obtain the start and end time of the burst signal, separate the burst signal data according to the duration and sampling rate; and is also used to perform cross-frame splicing on the burst signal that does not end in the current data frame.

7. The communication signal adaptive demodulation system of a non-cooperative communication mode according to claim 5, characterized in that: The modulation identification and parameter estimation module is used to estimate the modulation type and characteristic parameters of the signal to be demodulated, and the characteristic parameters include signal code rate, frequency interval and signal-to-noise ratio; it is also used to identify new signals, and when the signal to be demodulated is identified as a new signal, the modulation type and characteristic parameters of the new signal are written into the signal parameter library as signal data of the new signal.

8. The communication signal adaptive demodulation system of a non-cooperative communication mode according to claim 5, characterized in that: The signal demodulation module is used to obtain corresponding signal demodulation parameters through a signal parameter library for demodulation; the signal demodulation module includes a burst signal demodulation component and a continuous signal demodulation component; the burst signal demodulation component is used to capture, synchronize and judge the burst signal through known parameters when the synchronization header and channel probe information of the burst signal match the signal knowledge accumulation database; the continuous signal demodulation component is used to read the signal demodulation parameters of the corresponding continuous signal from the signal parameter library and demodulate the continuous signal for blind synchronization and estimation.

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