Dynamic threshold capturing method and system for continuous phase modulation

Abstract

The invention relates to a dynamic threshold capturing method and system for continuous phase modulation, and the method comprises the steps: 1, enabling a locally generated synchronization sequence to slide relative to a receiving sequence through the self-correlation characteristic of the synchronization sequence, and carrying out the integral calculation of a correlation value in a symbol period; step 2, according to the constant envelope characteristic of the continuous phase modulation signal, calculating the signal quality by using the envelope fluctuation characteristic of the receiving sequence corresponding to the local synchronization sequence in the symbol period; step 3, dynamically selecting a related threshold according to the current signal quality condition; and 4, judging whether the correlation value calculated in the step 1 is greater than the threshold determined in the step 3, if so, successfully capturing, and if not, repeating the step 1. According to the method, the capture probability can be effectively improved, the false alarm probability is reduced, and the system transmission reliability and the communication distance are ensured.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and in particular relates to a dynamic threshold capture method and system for continuous phase modulation. Background Art

[0002] Continuous Phase Modulation (CPM) is an important modulation technique in digital communications. Its core characteristic is that the signal phase remains continuous, without phase jumps, during symbol switching. This characteristic enables it to excel in spectral efficiency, interference mitigation, and power efficiency, leading to its widespread use in various communication systems.

[0003] In wireless communication systems, synchronized signal reception remains a critical issue. The performance of the synchronization system directly impacts the reliability and applicability of the entire system, as well as its functionality and performance, ultimately limiting the quality and efficiency of wireless communications. The first step in signal synchronization is acquisition. Because the signal transmission delay between transmitter and receiver is unknown, acquisition requires performing sliding correlation in the time domain across all possible delays, ensuring that the phase difference between the local reference synchronization code and the received synchronization code is less than one symbol width.

[0004] Traditional techniques compare the correlation results generated at each moment with a pre-set threshold. Capture is successful if the result exceeds the threshold. The longer the synchronization sequence, the better the capture performance—higher the detection probability and lower the false alarm probability. However, the length of the synchronization sequence is often limited by factors such as hopping rate and transmission efficiency. Furthermore, for anti-interception and security reasons, synchronization sequences are often generated completely randomly, and their autocorrelation cannot be guaranteed. In both cases, when the capture threshold is set low, the capture probability is higher at low signal-to-noise ratios. However, at high signal-to-noise ratios, the false alarm probability increases at the sidelobes of the synchronization sequence or at the target signal of the non-synchronized sequence, which can have a serious adverse impact on the communication system. When the capture threshold is set high, the false alarm situation is improved at high signal-to-noise ratios, but at low signal-to-noise ratios, the capture probability decreases, making it difficult to match data demodulation performance and affecting transmission quality. Summary of the Invention

[0005] The purpose of the present invention is to provide a dynamic threshold capture method and system for continuous phase modulation. Without adding any waveform constraints, the method and system utilize the constant envelope characteristics of the continuous phase modulation signal to predict the signal quality of the received signal and dynamically adjust (set) the capture threshold, thereby effectively improving the capture probability while reducing the false alarm probability, thereby ensuring the reliability of system transmission and the communication distance.

[0006] The present invention provides a dynamic threshold capture method for continuous phase modulation, comprising the following steps:

[0007] Step 1: Using the autocorrelation characteristics of the synchronization sequence, the locally generated synchronization sequence is slid relative to the received sequence, and the correlation value within one symbol period is integrated and calculated;

[0008] Step 2, calculating the signal quality based on the constant envelope characteristic of the continuous phase modulation signal and utilizing the envelope fluctuation characteristics of the received sequence corresponding to the local synchronization sequence within the symbol period;

[0009] Step 3: Dynamically select the relevant threshold based on the current signal quality;

[0010] Step 4: Determine whether the correlation value calculated in step 1 is greater than the threshold determined in step 3. If so, the capture is successful; if not, repeat step 1.

[0011] Furthermore, the step 2 includes:

[0012] Using the received sequence y corresponding to the local synchronization sequence in the symbol period i The signal quality is calculated by the envelope fluctuation characteristics of (i=1,…N). The smoother the signal envelope, the higher the signal quality. The calculation formula is as follows:

[0013]

[0014] in:

[0015]

[0016] Furthermore, the step 3 includes:

[0017] Determine the value of γ. When it is greater than or equal to the threshold q, the current signal quality is determined to be good, the corresponding signal-to-noise ratio is high, and the capture probability is high. If the synchronization threshold is set too low, the false alarm probability will increase. In this case, the corresponding correlation threshold thr is set to a larger value thr1 to effectively avoid the risk of false alarms.

[0018] When γ is less than the threshold q, the current signal quality is judged to be poor and the corresponding signal-to-noise ratio is low. In order to improve the capture probability, the relevant threshold thr needs to be lowered and set to thr2, where thr1>thr2; the threshold q is used to distinguish signal quality, and the thresholds thr1 and thr2 are used for different capture thresholds corresponding to different signal qualities;

[0019] Furthermore, the threshold q, the threshold thr1, and the threshold thr2 are obtained by performing simulation tests on at least 1000 samples under different working environments.

[0020] The present invention also provides a dynamic threshold capture system for continuous phase modulation, comprising a dynamic threshold capture module. The dynamic threshold capture module executes the dynamic threshold capture method for continuous phase modulation.

[0021] The present invention also provides a non-transitory computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the dynamic threshold capture method for continuous phase modulation is implemented.

[0022] The present invention also provides an electronic device, comprising:

[0023] A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the dynamic threshold capture method for continuous phase modulation by executing the computer instructions.

[0024] The above solution, through the dynamic threshold capture method and system for continuous phase modulation, has the following technical effects:

[0025] 1) Without adding any additional synchronization sequence overhead or any waveform constraints, the capture probability can be improved, the false alarm probability can be reduced, and the reliability of system transmission and communication distance can be guaranteed.

[0026] 2) Due to the improved capture performance, the overhead of the synchronization sequence can be appropriately reduced, and the transmission of effective data can be increased to improve the transmission efficiency or coding gain.

[0027] 3) It will not increase the additional hardware cost and can be achieved by adding software modules.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flowchart of a dynamic threshold capture method for continuous phase modulation according to an embodiment of the present invention;

[0030] Figure 2 The figure is a schematic structural diagram of an electronic device of the present invention. DETAILED DESCRIPTION

[0031] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0032] Ginseng Figure 1As shown, this embodiment provides a dynamic threshold capture method for continuous phase modulation, including the following steps:

[0033] Step 1: Using the autocorrelation characteristics of the synchronization sequence, the locally generated synchronization sequence is slid relative to the received sequence, and the correlation value within one symbol period is integrated and calculated;

[0034] Step 2: Based on the constant envelope characteristic of the continuous phase modulation signal (the constant envelope characteristic of the continuous phase modulation signal is one of its core technical advantages, the amplitude of the signal remains fixed during the entire transmission process and does not change with the change of the modulation symbol), the received sequence y corresponding to the local synchronization sequence in the symbol period is used. i The signal quality is calculated by the envelope fluctuation characteristics of (i=1,…N). The smoother the signal envelope, the higher the signal quality. The calculation formula is as follows:

[0035]

[0036] in:

[0037]

[0038] Step 3: Dynamically select the relevant threshold based on the current signal quality.

[0039] The value of γ is determined. When it is greater than or equal to the threshold q, the current signal quality is considered to be good and the corresponding signal-to-noise ratio is high. At this time, the capture probability is high. However, if the synchronization threshold is set too low, the false alarm probability will increase (false alarms will occur at the sidelobes of the synchronous sequence or the target signal of the asynchronous sequence). The corresponding correlation threshold thr is set to a larger value thr1 to effectively avoid the risk of false alarms.

[0040] When γ is less than the threshold q, the current signal quality is considered poor, and the corresponding signal-to-noise ratio is low. In this case, the capture probability needs to be improved. Lowering the relevant threshold thr appropriately to thr2 (where thr1 > thr2) does not increase the risk of false alarms. The threshold q is used to distinguish signal quality, and the thresholds thr1 and thr2 are used to set different capture thresholds for different signal qualities.

[0041] The threshold q, threshold thr1, and threshold thr2 need to be obtained through simulation tests on at least 1000 samples in different working environments.

[0042] Step 4: Determine whether the correlation value calculated in step 1 is greater than the threshold determined in step 3. If so, the capture is successful; if not, repeat step 1.

[0043] This dynamic threshold capture method uses the constant envelope characteristics of the continuous phase modulation signal without adding any waveform constraints to predict signal quality and dynamically set the capture threshold, thereby increasing the capture probability and reducing the false alarm probability, thereby improving the transmission performance of the communication system.

[0044] This embodiment further provides a dynamic threshold capture system for continuous phase modulation, including a dynamic threshold capture module. The dynamic threshold capture module executes the dynamic threshold capture method for continuous phase modulation.

[0045] This embodiment further provides a non-transitory computer-readable storage medium, which stores computer instructions. When the computer instructions are executed by a processor, the dynamic threshold capture method for continuous phase modulation is implemented.

[0046] Ginseng Figure 2 As shown, this embodiment further provides an electronic device, including:

[0047] The memory 201 and the processor 202 are communicatively connected to each other, the memory 201 stores computer instructions, and the processor 202 executes the dynamic threshold capture method for continuous phase modulation by executing the computer instructions.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dynamic threshold capture method for continuous phase modulation, characterized in that: The steps include: Step 1: Using the autocorrelation characteristics of the synchronization sequence, the locally generated synchronization sequence is slid relative to the received sequence, and the correlation value within one symbol period is integrated and calculated; Step 2, calculating the signal quality based on the constant envelope characteristic of the continuous phase modulation signal and utilizing the envelope fluctuation characteristics of the received sequence corresponding to the local synchronization sequence within the symbol period; Step 3: Dynamically select the relevant threshold based on the current signal quality; Step 4: Determine whether the correlation value calculated in step 1 is greater than the threshold determined in step 3. If so, the capture is successful; if not, repeat step 1.

2. The dynamic threshold capture method for continuous phase modulation according to claim 1, characterized in that: The step 2 includes: Using the received sequence y corresponding to the local synchronization sequence in the symbol period i The signal quality is calculated by the envelope fluctuation characteristics of (i=1,…N). The smoother the signal envelope, the higher the signal quality. The calculation formula is as follows: in:

3. The dynamic threshold capture method for continuous phase modulation according to claim 2, characterized in that: The step 3 includes: Determine the value of γ. When it is greater than or equal to the threshold q, the current signal quality is determined to be good, the corresponding signal-to-noise ratio is high, and the capture probability is high. If the synchronization threshold is set too low, the false alarm probability will increase. In this case, the corresponding correlation threshold thr is set to a larger value thr1 to effectively avoid the risk of false alarms. When γ is less than the threshold q, the current signal quality is determined to be poor and the corresponding signal-to-noise ratio is low. At this time, in order to improve the capture probability, the relevant threshold thr needs to be lowered and set to thr2, where thr1>thr2; the threshold q is used to distinguish signal quality, and the thresholds thr1 and thr2 are used for different capture thresholds corresponding to different signal qualities.

4. The dynamic threshold capture method for continuous phase modulation according to claim 3, characterized in that: The threshold q, threshold thr1 and threshold thr2 are obtained by performing simulation tests on at least 1000 samples under different working environments.

5. A dynamic threshold capture system for continuous phase modulation, characterized in that: It comprises a dynamic threshold capture module, which executes the dynamic threshold capture method for continuous phase modulation according to any one of claims 1 to 4.

6. A non-transitory computer-readable storage medium, characterized in that The non-transitory computer-readable storage medium stores computer instructions, and when the computer instructions are executed by a processor, the dynamic threshold capture method for continuous phase modulation according to any one of claims 1 to 4 is implemented.

7. An electronic device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the dynamic threshold capture method for continuous phase modulation as described in any one of claims 1 to 4 by executing the computer instructions.

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