WO2021243799A1

WO2021243799A1 - Signal detection and acquisition method and device, receiver, and storage medium

Info

Publication number: WO2021243799A1
Application number: PCT/CN2020/100752
Authority: WO
Inventors: 李建龙; 郑波浪; 李晓明; 刘伟; 熊艳伟
Original assignee: 北京升哲科技有限公司
Priority date: 2020-06-01
Filing date: 2020-07-08
Publication date: 2021-12-09
Also published as: TW202147797A; CN111641420A; TWI758774B; CN111641420B

Abstract

The present application discloses a signal detection and acquisition method and device, a receiver, and a storage medium. The method comprises: obtaining a current received signal sequence and a current receiver state corresponding thereto; performing timing position correction and frequency offset correction on the current received signal sequence, and performing segmented Fourier transform processing on the corrected signal sequence; updating the current receiver state according to a result of the segmented Fourier transform processing and a state switching condition matching the current receiver state; and returning to the step of obtaining a current received signal sequence and a current receiver state corresponding thereto until it is determined that a frame signal to which the current received signal sequence belongs is a target signal.

Description

Signal detection and capture method, device, receiver and storage medium

This disclosure claims the priority of a Chinese patent application filed with the Chinese Patent Office with an application number of 202010486272.2 on June 1, 2020, and the entire content of the above application is incorporated into this disclosure by reference.

Technical field

This application relates to the field of wireless communication technology, for example, to a signal detection and acquisition method, device, receiver, and storage medium.

Background technique

In order to meet the communication between long-distance IoT devices, low-power, high-capacity wide area networks have emerged, such as Lora and sigfox working in unlicensed frequency bands, and NB-IoT working in licensed frequency bands. The spread spectrum technology has a high anti-interference tolerance, and even the signal is annihilated in the noise, the information can be received correctly, which is suitable for long-distance communication.

In related technologies, the low-power wide area network represented by Lora uses linear sweep signals as spread-spectrum signals. Since Fourier transform is used for signal processing in many scenarios, it can simplify calculations and improve efficiency. To realize the spread spectrum signal, the receiver basically uses Fourier transform to detect and capture the signal. However, the larger the spreading factor that the receiver can support, the longer the received signal sequence of a single Fourier transform. When the sequence length of the received signal is very long, on the one hand, the calculation amount of the Fourier transform is very large, the calculation time required is very long, and the data processing speed is slow. On the other hand, it needs to occupy more hardware resources and increase Consumption of resources.

Summary of the invention

The embodiments of the present application provide a signal detection and acquisition method, device, receiver, and storage medium, so as to reduce hardware resource consumption and increase data processing speed while ensuring the accuracy of target signal acquisition.

In the first aspect, an embodiment of the present application provides a signal detection and acquisition method applied to a receiver, including:

Acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

Performing corresponding timing position correction and frequency offset correction on the current received signal sequence according to the operation matching the current receiver state, and performing segmented Fourier transform processing on the corrected current received signal sequence;

Updating the current receiver state according to the result of the segmented Fourier transform processing and the state switching condition matching the current receiver state, and the receiver includes a plurality of selectable switching states;

Return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

In the second aspect, an embodiment of the present application also provides a signal detection and acquisition device, which is applied to a receiver, and includes:

An acquiring module configured to acquire the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

The transformation module is configured to perform corresponding timing position correction and frequency offset correction on the current received signal sequence according to an operation matching the current receiver state, and perform segmentation Fourier on the corrected current received signal sequence Leaf transformation processing;

The state update module is configured to update the current receiver state according to the result of the segmented Fourier transform processing and the state switching condition matching the current receiver state, and the receiver includes a plurality of options Switch state

The loop module is configured to return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

In a third aspect, an embodiment of the present application also provides a receiver, the receiver including:

processor;

Storage device for storing programs,

When the program is executed by the processor, the processor realizes the signal detection and capture method provided by any embodiment of the present application.

In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium having a computer program stored on the computer-readable storage medium. When the computer program is executed by a processor, the signal provided by any embodiment of the present application is realized. Detection and capture methods.

Description of the drawings

Figure 1a is a flowchart of a signal detection and capture method in Embodiment 1 of the present application;

FIG. 1b is a time domain diagram of a linear frequency sweep signal in Embodiment 1 of the present application;

FIG. 1c is a frequency domain diagram of a linear frequency sweep signal in Embodiment 1 of the present application;

FIG. 1d is a schematic diagram of a frame structure of a received signal in Embodiment 1 of the present application;

FIG. 1e is a schematic diagram of the state switching of a receiver in Embodiment 1 of the present application;

2 is a flowchart of a signal detection and capture method in the second embodiment of the present application;

FIG. 3 is a schematic structural diagram of a signal detection and capture device in the third embodiment of the present application;

Fig. 4 is a schematic structural diagram of a receiver in the fourth embodiment of the present application.

detailed description

The application will be further described in detail below with reference to the drawings and embodiments. It is understandable that the specific embodiments described here are only used to explain the application, but not to limit the application. In addition, it should be noted that, for ease of description, the drawings only show a part of the structure related to the present application, but not all of the structure.

Example one

Figure 1a is a flow chart of a signal detection and capture method in the first embodiment of the present application. This embodiment can be applied to a situation where a long received signal sequence is subjected to Fourier transform to detect and capture a target signal. The method can be executed by a signal detection and acquisition device, which can be implemented by hardware and/or software, and can be integrated in a receiver. As shown in Figure 1a, the method is applied to a receiver and includes:

Step 110: Obtain the current received signal sequence and the current receiver state corresponding to the current received signal sequence.

In this embodiment, the received signal sequence is intercepted from the frame signal received by the receiver through the sliding window. By moving the position of the sliding window, different received signal sequences can be intercepted in the received frame signal. The received frame signal may include attenuated sweep signal, noise, and data signal. The received signal sequence in this embodiment refers to the attenuated sweep signal plus noise. The sweep signal is used to realize signal detection and signal detection. capture. As shown in Figure 1b, the sweep signal uses a sinusoidal signal as excitation, the amplitude of the excitation remains unchanged, and the frequency of the excitation increases with a fixed step as the time changes, and after frequency domain transformation, the sweep signal It can achieve sparse representation in the frequency domain, thereby presenting an energy focusing effect, as shown in Figure 1c.

In this embodiment, the receiver may be a non-coherent receiver. The current receiver state indicates the signal processing stage of the receiver in the current received signal processing process. The receiver performs different processes on the current received signal sequence in different receiver states. Signal processing operations to achieve different processing effects. Exemplarily, when the current receiver state is the first state, it means that the receiver is currently in the initialization stage of received signal processing. The operation matching the current receiver state can determine whether the current received signal sequence is a frame synchronization word.

Step 120: Perform corresponding timing position correction and frequency offset correction on the current received signal sequence according to the operation matched with the current receiver state, and perform segmented Fourier transform processing on the corrected current received signal sequence.

In this embodiment, considering that the received signal sequence may have a frequency offset and a timing position offset of the sliding window, in order to improve the accuracy of the Fourier transform processing result corresponding to the current received signal sequence, it is necessary to obtain information corresponding to the current received signal sequence. After the current receiver state, you can first perform the corresponding timing position correction and frequency offset correction on the current received signal sequence according to the operation matching the current receiver state, so as to roughly eliminate the frequency offset and the timing position offset of the sliding window. The effect of subsequent piecewise Fourier transform processing.

Optionally, performing the corresponding timing position correction and frequency offset correction on the current received signal sequence according to the operation matching the current receiver state may include: if the current receiver state is the initialized first state, then the current received signal is not corrected. The sequence performs the corresponding timing position correction and frequency offset correction; if the current receiver state is not the first state, the current received signal sequence is corrected according to the spectral peak position of the historical received signal sequence, and the current received signal sequence is corrected according to the The frequency offset value of the historical received signal sequence, and the fractional frequency offset correction of the current received signal sequence.

In this embodiment, the position of the peak value of the spectrum obtained after the Fourier transform processing of the historical sweep signal sequence closest to the current sweep signal sequence (that is, the previous sweep signal sequence of the current sweep signal sequence) can be used to correct The current received signal sequence undergoes rough integer multiple timing position correction. In addition, considering that the received signal sequence without frequency offset is subjected to Fourier transform processing, the peak position of the spectrum is usually fixed. Therefore, it can be based on the transformation processing of one or more historical received signal sequences before the current received signal sequence. The frequency offset value calculated as a result is used to roughly correct fractional frequency offset of the current received signal sequence.

In this embodiment, when the initialized first state processes the first received signal sequence obtained by the sliding window, the current received signal sequence does not have the conversion processing result of the historical received signal sequence to be used. When the first state processes the first received signal sequence, For a received signal sequence, the transformation processing result of the historical received signal sequence before the current received signal sequence is usually inaccurate and cannot be used. Therefore, the corresponding timing position correction and frequency offset correction of the current received signal sequence cannot be performed in the first state, and the corresponding timing position of the current received signal sequence can be performed according to the conversion processing result of the historical received signal sequence in the non-first state. Correction and frequency offset correction.

Optionally, performing segmental Fourier transform processing on the corrected current received signal sequence may include: dividing the corrected current received signal sequence into a first number of subsequences, and performing Fourier transform on each subsequence Leaf transform; modulo the Fourier transform results of the first number of subsequences, and perform incoherent superposition processing on the processed Fourier transform results; according to the Fourier transform results after incoherent superposition processing , To determine the spectral peak position and frequency offset value of the current received signal sequence.

In this embodiment, the corrected current received signal sequence and the unmodulated original frequency sweep signal sequence are subjected to a conjugate multiplication operation for despreading, and then the current received signal sequence with a ^{sequence length of N=2 SF is equally divided into} The first number of sub-sequences, and Fourier transform is performed on each sub-sequence, where SF is the spreading factor. For the convenience of calculation, the first number can be a power of two. Then square the modulus of the amplitude spectrum in the Fourier transform result of each sub-sequence to eliminate the phase difference, and then perform incoherent superposition processing on the processed Fourier transform result, from the incoherent superposition processed Fourier Find the subscript corresponding to the maximum value of the spectrum in the transform result as the position of the spectrum peak of the current received signal sequence, and roughly calculate the current received signal sequence according to the magnitude relationship of the spectrum value of the nearest frequency point on both sides of the spectrum peak in the Fourier transform result The frequency offset value.

Step 130: Update the state of the receiver according to the result of the conversion processing and the state switching condition that matches the current state of the receiver.

In this embodiment, the receiver includes multiple selectable switching states. For example, the first state of initialization, the second state of detecting the frame synchronization word, the third state of detecting the first frequency synchronization word, the fourth state of detecting the second frequency synchronization word, the fifth state of separating the time-frequency offset, and the estimated score The sixth state with multiple time shifts, etc. Each receiver state actually corresponds to the frame structure of the frame signal received by the receiver one-to-one.

Exemplarily, as shown in Fig. 1d, the framing based on the frequency sweep signal includes a preamble part and a load part. The preamble signal is used for signal detection and signal capture, and the preamble part includes a plurality of frame synchronization words (Preamble). ), 2 frequency synchronization words (SyncWord) and 2.25 fine synchronization words (FineSyncWord). The frame synchronization word is composed of multiple unmodulated frequency sweep signals, which are used for the initial discrimination of signal detection and capture. The frequency synchronization word represents the network identification number, which is unique to each network, and is equivalent to a human ID card, which is used for the final identification of signal capture. Different frequency synchronization word and frame synchronization words is that it is modulated, in other words, the frequency of the synchronization word is not a frequency f _0, but f ₀ + k _i Δf, wherein, k _i represents the modulation information, different frequencies The synchronization word may be configured with different k _i values. The fine sync word is used to estimate the time-frequency offset of the captured target signal to ensure that the time and time-frequency offset of the target signal sent to the demodulation module of the receiver are aligned. The fine sync word is also an unmodulated frequency sweep signal, but The sweep direction of the fine sync word is just opposite to the sweep direction of the frequency sync word and the frame sync word.

Optionally, updating the receiver state according to the conversion processing result and the state switching condition that matches the current receiver state may include: when the current receiver state is the initialized first state, determining the current receiver state according to the conversion processing result Whether the signal-to-noise ratio of the signal sequence is greater than the threshold threshold; if so, the receiver state is updated to the second state of detecting the frame synchronization word, otherwise, the current receiver state is kept unchanged.

In this embodiment, when the current receiver state is the first initialized state, the current received signal sequence and the unmodulated original sweep signal sequence are subjected to conjugate multiplication operation, and after despreading, the current received signal is directly The sequence is subjected to segmented Fourier transform processing to obtain the peak position of the frequency spectrum and the frequency offset value. The ratio of the peak power to the sum of other powers except the peak power is regarded as the signal-to-noise ratio of the current received signal sequence. If the signal-to-noise ratio of the current received signal sequence is detected to be greater than the threshold threshold, it is considered that a sweep signal is detected. Switch the receiver state to the second state of detecting the frame synchronization word, so that the receiver can process the new received signal sequence in the second state; otherwise, skip the current received signal sequence and continue to slide in the first state The next received signal sequence acquired by the window is processed, as shown in Figure 1e.

Optionally, updating the receiver state according to the conversion processing result and the state switching condition that matches the current receiver state may include: when the current receiver state is the second state for detecting the frame synchronization word, if the current state is detected The signal-to-noise ratio of the received signal sequence is greater than the threshold threshold, and the current received signal sequence is determined to be the frame synchronization word according to the spectral peak position of the current received signal sequence, then the counter is accumulated; if the accumulated value of the counter meets the quantity threshold condition, Then update the receiver state to the third state of detecting the first frequency synchronization word; when the current receiver state is the second state of detecting the frame synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is less than or equal to the threshold threshold, And/or, according to the spectral peak position of the current received signal sequence, it is determined that the current received signal sequence is not a frame synchronization word, and then the receiver state is switched back to the initialized first state.

In this embodiment, when the current receiver state is the second state for detecting the frame synchronization word, the current received signal sequence is first corresponded to the current received signal sequence according to the spectral peak position and frequency offset value of the historical received signal sequence before the current received signal sequence. Integer timing position correction and fractional frequency offset correction. Then, the corrected current received signal sequence and the unmodulated original frequency sweep signal sequence are conjugate multiplied to perform despreading, and the despread current received signal sequence is subjected to segmented Fourier transform processing to obtain the peak value of the spectrum. Position and frequency offset value. If it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold value, and the current received signal sequence is determined to be the frame synchronization word according to the spectral peak position of the current received signal sequence, the counter is accumulated, and the counter is used to calculate the second The number of frame sync words detected in the state is counted. When the value of the counter is equal to the preset number, for example, equal to 3, it is considered that the frame synchronization word is detected, and the receiver state can be updated to the third state of detecting the first frequency synchronization word, and the counter is cleared. If it is detected that the current received signal sequence does not meet the conditions of SNR and frame synchronization word at the same time before the value of the counter reaches the preset number, it is considered that the previously determined received signal sequence is a frame synchronization word is a misjudgment, and the receiver status Switch back to the first state of initialization, as shown in Figure 1e.

In this embodiment, when there is no frequency offset, the subscript corresponding to the ideal spectral peak position of the frame synchronization word is 0, but in reality, due to the possible timing position deviation or frequency deviation, the spectral peak position generally does not exactly correspond to the subscript 0 Therefore, in order to prevent missed detection, when the difference between the spectral peak position of the current received signal sequence and the ideal spectral peak position is within the effective range, the current received signal sequence can be regarded as a frame synchronization word.

Optionally, updating the receiver state according to the conversion processing result and the state switching condition that matches the current receiver state may include: when the current receiver state is the third state for detecting the first frequency synchronization word, if it is detected When the signal-to-noise ratio of the current received signal sequence is greater than the threshold value, and the current received signal sequence is determined to be the frame synchronization word according to the spectral peak position of the current received signal sequence, the current receiver state is kept unchanged; the current receiver state is the detection first In the third state of a frequency synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold, and the current received signal sequence is determined to be the first frequency synchronization word according to the spectral peak position of the current received signal sequence, and the first If the frequency synchronization word matches the first frequency synchronization word of the target signal, the receiver state is updated to the fourth state for detecting the second frequency synchronization word; otherwise, the receiver state is switched back to the initialized first state.

In this embodiment, when the current receiver state is the third state for detecting the first frequency synchronization word, the current received signal sequence is subjected to the same Fourier transform processing as the second state, and the current received signal sequence is calculated according to the result of the transform processing If the signal-to-noise ratio is greater than the threshold value and it is determined that the current received signal sequence is a frame synchronization word, that is, the first frequency synchronization word has not been detected, the current receiver state is maintained as the third state unchanged. If the signal-to-noise ratio is greater than the threshold threshold, and the difference between the current received signal sequence spectrum peak position and the ideal spectrum peak position of the first frequency synchronization word is within the effective range, it is determined that the current received signal sequence is the first frequency synchronization word, In addition, if the first frequency synchronization word matches the first frequency synchronization word of the target signal to be captured, the receiver state is updated to the fourth state for detecting the second frequency synchronization word; otherwise, the receiver state is switched back to the initialized first frequency synchronization word. One state, as shown in Figure 1e.

Optionally, updating the receiver state according to the conversion processing result and the state switching condition that matches the current receiver state may include: when the current receiver state is the fourth state for detecting the second frequency synchronization word, if it is detected The signal-to-noise ratio of the current received signal sequence is greater than the threshold threshold, and the current received signal sequence is determined to be the second frequency synchronization word according to the spectral peak position of the current received signal sequence, and the second frequency synchronization word is the second frequency synchronization word of the target signal If it matches, the receiver state is updated to the fifth state of the separated frequency offset; otherwise, the receiver state is switched back to the initialized first state.

In this embodiment, when the current receiver state is the fourth state for detecting the second frequency synchronization word, the current received signal sequence is subjected to the same Fourier transform processing as the second state, and the current received signal sequence is calculated according to the result of the transform processing If the signal-to-noise ratio is greater than the threshold and the difference between the peak position of the current received signal sequence and the ideal peak position of the second frequency synchronization word is within the effective range, it is determined that the current received signal sequence is the second Frequency synchronization word, and if the second frequency synchronization word matches the second frequency synchronization word of the target signal to be captured, the receiver state is updated to the fifth state of the separated time frequency offset, otherwise, the receiver state is switched back to the initialization The first state is shown in Figure 1e.

Step 140: Return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

Optionally, determining that the frame signal to which the current received signal sequence belongs is the target signal may include: if the second frequency synchronization word matches the second frequency synchronization word of the target signal, determining that the frame signal to which the current received signal belongs is the target signal.

In this embodiment, the frequency synchronization word in the frame structure is used for the final judgment of signal capture. When the two frequency synchronization words of the received signal match the two frequency synchronization words of the target signal, in other words, when the second frequency synchronization word matches the second frequency synchronization word of the target signal, or in other words, the receiver status is updated When it is the fifth state of separating the time-frequency offset, the received signal is considered to be the target signal to be captured. If the target signal has not been determined after processing the current received signal sequence, return to the operation of obtaining the current received signal sequence and the current receiver state corresponding to the current received signal sequence, and continue to process the next received signal sequence until it is determined Until the target signal.

The technical solution of the embodiment of the present application is applied to the receiver, by acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence; according to the operation matching the current receiver state, the current received signal sequence is corresponding The timing position correction and frequency offset correction are performed on the corrected current received signal sequence, and the segmented Fourier transform processing is performed on the corrected current received signal sequence; the receiver state is updated according to the transformation processing result and the state switching condition matching the current receiver state, Return to the operation of obtaining the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal, which solves the problem of long received signal sequences in related technologies. , The problem of slow data processing speed and high resource consumption can reduce hardware resource consumption and increase data processing speed while ensuring the accuracy of target signal capture.

Example two

2 is a flowchart of a signal detection and capture method in the second embodiment of the present application. This embodiment is a modification on the basis of the above-mentioned embodiment, and provides that the frame signal to which the current received signal sequence belongs is determined as the target signal A step of. The signal detection and capture method provided by the second embodiment of the present application will be described below with reference to FIG. 2, which includes the following steps:

Step 210: Obtain the current received signal sequence and the current receiver state corresponding to the current received signal sequence.

Step 220: Perform corresponding timing position correction and frequency offset correction on the current received signal sequence according to the operation matching the current receiver state, and perform segmented Fourier transform processing on the corrected current received signal sequence.

Exemplarily, the transmitter selects an appropriate spreading factor SF according to external communication conditions, so the length of a single received signal sequence is N=2 ^SF chips. Suppose that the parameter T is the length of time required for the current received signal sequence, and the parameter T _c is the length of time each chip lasts.

Frequency deviation,

Time skew

Original received signal sequence after the sequence U _{n (n),} if the current state of the receiver to initialize a first state, the current received signal directly to the local sequence be unmodulated conjugated by despreading operation, if the currently received If the machine state is not in the first state, first, according to the frequency peak position and frequency offset value of the previous historical received signal sequence, perform the corresponding integer timing position correction and fractional frequency offset correction for the current received signal sequence, and then compare it with the local signal sequence. The modulated original received signal sequence U _base (n) performs a conjugate multiplication operation:

in,

p is a parameter that affects the frequency offset, and m is a parameter that affects the time offset.

Furthermore, the current received signal sequence whose sequence length is N=2 ^SF is divided into L equal-length sub-sequences. For the convenience of calculation, L can be a power of 2, and the first sub-sequence with a length of N/L is The result of the inner transformation is:

Among them, k represents the k-th frequency point among the N frequency points from 0 to 2π.

By analogy, the results of the Fourier transform of other subsequences are:

It can be seen that the Fourier transform results of the L subsequences only differ in phase, and the subscript value corresponding to the spectral peak value is 1/L times the subscript value corresponding to the spectral peak value of the N-point Fourier transform, and the spectral peak value is also It is 1/L times the peak value of the spectrum of the N-point Fourier transform. The Fourier transform results of the L subsequences are subjected to modulo processing to eliminate the phase difference, and then the incoherent superposition processing is performed. The result of the incoherent superposition processing is denoted as X(k,n). Calculate the index value Index_l=arg max(|X(k,n)|) corresponding to the maximum value of the spectrum from the L subsequences, then the non-coherent receiver obtains the spectrum peak position of the current received signal sequence of length N as index_l ·L.

In this embodiment, after the incoherent superposition processing, the processing result obtained has the problems of integer timing position deviation and fractional frequency deviation. Calculate the spectral peak position of L subsequences of length N/L in a non-coherent way as index_l·L, and the sequence length obtained by the coherent receiver is N. The spectral peak position of the current received signal sequence is Index_n, the positions of both The error is [-L:L], therefore, the spectral peak position of the Fourier transform processing result can also be used to compensate for the time error. In addition, the frequency offset accuracy estimated from the Fourier transform result of the subsequence of length N/L is L times worse than the frequency offset accuracy estimated from the Fourier transform result of the received signal sequence of length N. The frequency offset compensation can be further performed. After the time error is compensated, the frequency offset accuracy can reach the same level as the coherent receiver.

In this embodiment, if the current receiver state is the third state for detecting the first frequency synchronization word, it has been determined that the frame synchronization word has been detected. At this time, the timing position can be further corrected by using the spectral peak position obtained after Fourier transform processing. Deviation and frequency deviation, reduce the deviation between the timing position of the current received signal sequence and the ideal timing position, and improve the estimation accuracy of frequency deviation while reducing unnecessary calculations.

Step 230: Update the state of the receiver according to the result of the conversion processing and the state switching condition matching the current receiver state.

Step 240: Return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

Step 250: Update the current received signal sequence, and estimate the time-frequency offset of the target signal according to the current receiver state corresponding to the updated current received signal sequence.

It should be noted that the protection method of this embodiment is applied to the demodulation module of the non-coherent receiver. The demodulation module is functionally divided into signal detection and capture and demodulation and decoding of the captured target signal. In order to facilitate the The target signal is demodulated and decoded. After the target signal is determined, the current received signal sequence must be updated continuously, and the time-frequency offset of the target signal is estimated according to the current receiver state corresponding to the updated current received signal sequence.

In this embodiment, after determining that the frame signal to which the current received signal sequence belongs is the target signal, the current receiver state switches to the fifth state, and the next received signal sequence is acquired as the current received signal sequence. At this time, the current sweep signal sequence is The first fine sync word. According to the operation matching the fifth state, first perform the corresponding segmented Fourier transform processing on the current received signal sequence, and then use the feature that the sweep direction of the fine sync word is opposite to the sweep direction of the frame sync word and frequency sync word , Use the spectral peak position after Fourier transform to separate the timing position deviation from the integer frequency deviation, and estimate the integer frequency deviation of the target signal.

In this embodiment, after the calculation of the first fine synchronization word in the fifth state is completed, the current receiver state is switched to the sixth state with the estimated fractional time offset, and the current received signal sequence is updated, that is, it enters the second state. A fine synchronization word. According to the operation matching the sixth state, first perform the corresponding integer timing position correction, integer multiple frequency offset correction and fractional frequency offset correction on the current received signal sequence, and then perform interpolation operations on the corrected current received signal sequence , Estimate the fractional timing position deviation, and realize the time deviation estimation accuracy is improved to within 0.25 chips, so as to obtain the time-frequency deviation of the current received signal sequence, that is, the time-frequency deviation of the target signal. It should be noted that, in this embodiment, an interpolation operation may be used to estimate the fractional timing position deviation, or other operations may be used.

In this embodiment, when the current receiver state is the fifth state and the sixth state, it indicates that it has entered the fine synchronization stage of signal processing. The fine synchronization word can be used to distinguish the integer multiple timing position deviation of the sliding window from the integer multiple frequency offset Open to improve the estimation accuracy of the fractional timing position deviation, and calculate the time-frequency offset of the target signal, so as to demodulate the target signal according to the time-frequency offset.

Step 260: Demodulate the target signal according to the estimated time-frequency offset of the target signal.

In this embodiment, after the time-frequency offset value of the target signal is estimated in the fine synchronization stage, the current receiver state switches to the seventh state of correcting the time-frequency offset, and the target signal is time-frequency offset corrected according to the estimated time-frequency offset value , And then perform subsequent signal processing operations such as demodulation on the corrected target signal.

Example three

Fig. 3 is a schematic structural diagram of a signal detection and capture device in the third embodiment of the present application. This embodiment can be applied to a situation where a long received signal sequence is subjected to Fourier transform to detect and capture a target signal. The device can be implemented by hardware and/or software, and generally can be integrated in a receiver. As shown in Figure 3, the device may include:

The acquiring module 310 is configured to acquire the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

The transform module 320 is configured to perform corresponding timing position correction and frequency offset correction on the current received signal sequence according to an operation matching the current receiver state, and perform segmented Fourier transform processing on the corrected current received signal sequence ；

The state update module 330 is configured to update the state of the receiver according to the result of the transformation processing and the state switching condition matching the current receiver state, the receiver including a plurality of selectable switching states;

The loop module 340 is configured to return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

Optionally, the transformation module 320 includes: a correction unit configured to:

If the current receiver state is the first initialized state, the corresponding timing position correction and frequency offset correction are not performed on the current received signal sequence;

If the current receiver state is not the first state, the current received signal sequence is corrected based on the spectral peak position of the historical received signal sequence, and the current received signal sequence is corrected according to the frequency offset value of the historical received signal sequence. The signal sequence undergoes fractional frequency offset correction.

Optionally, the transform module 320 includes a Fourier transform processing unit configured to:

Divide the corrected current received signal sequence into the first number of sub-sequences, and perform Fourier transform on each sub-sequence;

Perform modulo square processing on the Fourier transform results of the first number of subsequences, and perform incoherent superposition processing on the processed Fourier transform results;

According to the Fourier transform result after incoherent superposition processing, the spectral peak position and frequency offset value of the current received signal sequence are determined.

Optionally, the status update module 330 includes: a first update unit configured to:

When the current receiver state is the initialized first state, determine whether the signal-to-noise ratio of the current received signal sequence is greater than the threshold threshold according to the transformation processing result;

If yes, update the receiver state to the second state of detecting the frame synchronization word; otherwise, keep the current receiver state unchanged.

Optionally, the status update module 330 includes: a second update unit configured to:

When the current receiver state is the second state for detecting the frame synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold threshold, and the current received signal sequence is determined to be the frame synchronization word according to the spectral peak position of the current received signal sequence , Then accumulate the counter;

If the accumulated value of the counter meets the quantity threshold condition, updating the receiver state to the third state for detecting the first frequency synchronization word;

When the current receiver state is the second state for detecting frame synchronization words, if it is detected that the signal-to-noise ratio of the current received signal sequence is less than or equal to the threshold threshold, and/or the current received signal sequence is determined according to the spectral peak position of the current received signal sequence If it is not a frame synchronization word, the receiver state is switched back to the first state of initialization.

Optionally, the status update module 330 includes: a third update unit configured to:

When the current receiver state is the third state for detecting the first frequency synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold, and the current received signal sequence is determined to be a frame according to the spectral peak position of the current received signal sequence Synchronization word, keep the current receiver status unchanged;

When the current receiver state is the third state for detecting the first frequency synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold, and the current received signal sequence is determined to be the first according to the spectral peak position of the current received signal sequence A frequency synchronization word, and the first frequency synchronization word matches the first frequency synchronization word of the target signal, the receiver state is updated to the fourth state of detecting the second frequency synchronization word, otherwise, the receiver state is switched back to the initialized state The first state.

Optionally, the status update module 330 includes: a fourth update unit configured to:

When the current receiver state is the fourth state for detecting the second frequency synchronization word, if it is detected that the signal-to-noise ratio of the current received signal sequence is greater than the threshold threshold, and the current received signal sequence is determined to be the first according to the spectral peak position of the current received signal sequence Two frequency synchronization words, and the second frequency synchronization word matches the second frequency synchronization word of the target signal, then the receiver state is updated to the fifth state of the separated time frequency offset, otherwise, the receiver state is switched back to the first initialized state state.

Optionally, the circulation module 340 can be configured as:

If the second frequency synchronization word matches the second frequency synchronization word of the target signal, it is determined that the frame signal to which the current received signal belongs is the target signal.

The signal detection and capture device provided by the embodiment of the present application can execute the signal detection and capture method provided by any embodiment of the present application, and has functional modules and beneficial effects corresponding to the execution method.

Embodiment four

Fig. 4 is a schematic structural diagram of a receiver in the fourth embodiment of the present application. Figure 4 shows a block diagram of an exemplary receiver 12 suitable for implementing embodiments of the present application. The receiver 12 shown in FIG. 4 is only an example.

As shown in FIG. 4, the receiver 12 takes the form of a general-purpose computing device. The components of the receiver 12 may include: one or more processors or processing units 16, a system memory 28, and a bus 18 connecting different system components (including the system memory 28 and the processing unit 16).

The bus 18 represents one or more of several types of bus structures, including a memory bus or a memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any bus structure among multiple bus structures. For example, these architectures can include industry standard architecture (ISA) bus, microchannel architecture (MAC) bus, enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

The receiver 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the receiver 12, including volatile and non-volatile media, removable and non-removable media.

The system memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and/or cache memory 32. The receiver 12 may also include other removable/non-removable, volatile/nonvolatile computer system storage media. For example only, the storage system 34 may be used to read and write non-removable, non-volatile magnetic media (not shown in FIG. 4, usually referred to as a "hard drive"). Can provide disk drives for reading and writing to removable non-volatile disks (such as "floppy disks"), as well as reading and writing to removable non-volatile optical disks (such as CD-ROM, DVD-ROM or other optical media) Optical drive. In these cases, each drive can be connected to the bus 18 through one or more data media interfaces. The memory 28 may include at least one program product, the program product having a set (for example, at least one) of program modules, and these program modules are configured to perform the functions of each embodiment of the present application.

A program/utility tool 40 having a set of (at least one) program module 42 may be stored in, for example, the memory 28. Such program module 42 may include an operating system, one or more application programs, other program modules, and program data. Each of the examples or some combination may include the realization of a network environment. The program module 42 usually executes the functions and/or methods in the embodiments described in this application.

The receiver 12 can also communicate with one or more external devices 14 (such as keyboards, pointing devices, displays 24, etc.), and can also communicate with one or more devices that enable users to interact with the receiver 12, and/or communicate with Any device (such as a network card, modem, etc.) that enables the receiver 12 to communicate with one or more other computing devices. This communication can be performed through an input/output (I/O) interface 22. In addition, the receiver 12 may also communicate with one or more networks (for example, a local area network (LAN), a wide area network (WAN), and/or a public network, such as the Internet) through the network adapter 20. As shown in the figure, the network adapter 20 communicates with other modules of the receiver 12 through the bus 18. It should be understood that other hardware and/or software modules may be used in conjunction with the receiver 12. Other hardware and/or software modules may include: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data Backup storage system, etc.

The processing unit 16 executes various functional applications and data processing by running programs stored in the system memory 28, such as implementing the signal detection and capture methods provided in the embodiments of the present application.

That is: to implement a signal detection and acquisition method, applied to the receiver, including:

Acquire the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

According to the operation matching the current receiver state, perform corresponding timing position correction and frequency offset correction on the current received signal sequence, and perform segmented Fourier transform processing on the corrected current received signal sequence;

Update the receiver state according to the conversion processing result and the state switching condition matching the current receiver state, and the receiver includes a plurality of selectable switching states;

Return to the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.

Embodiment five

The fifth embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. The program is used to perform a signal detection and capture method when executed by a computer processor, and is applied to a receiver, including:

The computer storage medium of the embodiment of the present application may adopt any combination of one or more computer-readable media. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the above. Examples of computer-readable storage media (non-exhaustive list) may include: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable Programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above. In this document, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device.

The computer-readable signal medium may include a data signal propagated in baseband or as a part of a carrier wave, and computer-readable program code is carried therein. This propagated data signal can take many forms, and can include electromagnetic signals, optical signals, or any suitable combination of the foregoing. The computer-readable signal medium may also be any computer-readable medium other than the computer-readable storage medium. The computer-readable medium may send, propagate or transmit the program for use by or in combination with the instruction execution system, apparatus, or device .

The program code contained on the computer-readable medium can be transmitted by any suitable medium, which can include wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

The computer program code used to perform the operations of this application can be written in one or more programming languages or a combination thereof. The programming languages include object-oriented programming languages—such as Java, Smalltalk, C++, and also conventional Procedural programming language-such as "C" language or similar programming language. The program code can be executed entirely on the user's computer, partly on the user's computer, executed as an independent software package, partly on the user's computer and partly executed on a remote computer, or entirely executed on the remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any kind of network-including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (for example, using an Internet service provider to pass Internet connection).

Claims

A signal detection and acquisition method, applied to a receiver, includes:

Acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

According to the operation matching the current receiver state, perform corresponding timing position correction and frequency offset correction on the current received signal sequence, and perform segmented Fourier transform processing on the corrected current received signal sequence;

Updating the current receiver state according to the result of the segmented Fourier transform processing and the state switching condition matching the current receiver state, and the receiver includes a plurality of selectable switching states;

Return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.
The method according to claim 1, wherein, performing corresponding timing position correction and frequency offset correction on the current received signal sequence according to an operation matching the current receiver state, comprising:

When the current receiver state is not the first state, perform timing position correction on the current received signal sequence according to the spectral peak position of the historical received signal sequence, and correct the current received signal sequence according to the frequency offset value of the historical received signal sequence. The current received signal sequence performs fractional frequency offset correction.
The method according to claim 1, wherein performing the segmented Fourier transform processing on the corrected current received signal sequence comprises:

Dividing the corrected current received signal sequence into the first number of sub-sequences, and performing Fourier transform on each of the sub-sequences;

Performing modulo square processing on the Fourier transform results of the first number of the subsequences, and performing incoherent superposition processing on the processed Fourier transform results;

Determine the spectral peak position and frequency offset value of the current received signal sequence according to the Fourier transform result after the incoherent superposition processing.
The method according to claim 1, wherein the updating the current receiver state according to the result of the piecewise Fourier transform processing and the state switching condition matching the current receiver state comprises:

When the current receiver state is the initialized first state, determining whether the signal-to-noise ratio of the current received signal sequence is greater than a threshold threshold according to a result of the segmented Fourier transform processing;

Based on the judgment result that the signal-to-noise ratio of the current received signal sequence is greater than the threshold threshold, the current receiver state is updated to the second state of detecting the frame synchronization word.
The method according to claim 1, wherein the updating the current receiver state according to the result of the piecewise Fourier transform processing and the state switching condition matching the current receiver state comprises:

When the current receiver state is the second state for detecting the frame synchronization word, the signal-to-noise ratio of the current received signal sequence is detected to be greater than the threshold threshold, and the frequency spectrum peak position of the current received signal sequence is determined to determine the The current received signal sequence is the judgment result of the frame synchronization word, and the counter is accumulated;

Based on the judgment result that the accumulated value of the counter satisfies the quantity threshold condition, updating the current receiver state to the third state for detecting the first frequency synchronization word;

When the current receiver state is the second state for detecting frame synchronization words, based on the result of determining that the signal-to-noise ratio of the current received signal sequence is less than or equal to the threshold threshold, and according to the current received signal The sequence peak position of the spectrum determines that the current received signal sequence is not at least one of the determination results of the frame synchronization word, and the current receiver state is switched back to the initialized first state.
The method according to claim 1, wherein the updating the current receiver state according to the result of the piecewise Fourier transform processing and the state switching condition matching the current receiver state comprises:

When the current receiver state is the third state for detecting the first frequency synchronization word, it is determined based on the detection that the signal-to-noise ratio of the current received signal sequence is greater than the threshold value and the peak position of the spectrum of the current received signal sequence The current received signal sequence is the judgment result of the frame synchronization word, and the current receiver state is kept unchanged;

When the current receiver state is the third state for detecting the first frequency synchronization word, the signal-to-noise ratio based on the current received signal sequence is greater than the threshold threshold, and based on the spectral peak value of the current received signal sequence The location determines that the current received signal sequence is the first frequency synchronization word, and the first frequency synchronization word matches the first frequency synchronization word of the target signal, and the current receiver status is updated to detect the second frequency The fourth state of the synchronization word;

When the current receiver state is the third state for detecting the first frequency synchronization word, based on the judgment result that the signal-to-noise ratio of the current received signal sequence is not greater than the threshold threshold, and based on the current received signal The position of the spectral peak of the sequence determines that the current received signal sequence is not the first frequency synchronization word, and that the current received signal sequence that is the first frequency synchronization word does not match the first frequency synchronization word of the target signal At least one of the results is to switch the current receiver state back to the initialized first state.
The method according to claim 1, wherein the updating the current receiver state according to the result of the piecewise Fourier transform processing and the state switching condition matching the current receiver state comprises:

When the current receiver state is the fourth state for detecting the second frequency synchronization word, it is determined based on the detection that the signal-to-noise ratio of the current received signal sequence is greater than the threshold value and the spectral peak position of the current received signal sequence If the current received signal sequence is the second frequency synchronization word, and the second frequency synchronization word matches the second frequency synchronization word of the target signal, the current receiver status is updated to the first frequency offset separated. Five states

When the current receiver state is the fourth state for detecting the second frequency synchronization word, based on the result of determining that the signal-to-noise ratio of the current received signal sequence is not greater than the threshold threshold, and according to the current The result of determining that the current received signal sequence is not the second frequency synchronization word by the spectral peak position of the received signal sequence, and the current received signal sequence that is the second frequency synchronization word does not match the second frequency synchronization word of the target signal At least one of the results of the judgment is to switch the current receiver state back to the initialized first state.
The method according to claim 7, wherein the determining that the frame signal to which the currently received signal sequence belongs is the target signal comprises:

Based on the judgment result that the current received signal sequence that is the second frequency synchronization word matches the second frequency synchronization word of the target signal, it is determined that the frame signal to which the current received signal sequence belongs is the target signal.
A signal detection and acquisition device applied to a receiver, including:

An acquiring module configured to acquire the current received signal sequence and the current receiver state corresponding to the current received signal sequence;

The transformation module is configured to perform corresponding timing position correction and frequency offset correction on the current received signal sequence according to an operation matching the current receiver state, and perform segmentation Fourier on the corrected current received signal sequence Leaf transformation processing;

The state update module is configured to update the current receiver state according to the result of the segmented Fourier transform processing and the state switching condition matching the current receiver state, and the receiver includes a plurality of options Switch state

The loop module is configured to return to perform the operation of acquiring the current received signal sequence and the current receiver state corresponding to the current received signal sequence until it is determined that the frame signal to which the current received signal sequence belongs is the target signal.
A receiver, the receiver includes:

processor;

Storage device for storing programs,

When the program is executed by the processor, the processor realizes the signal detection and capture method according to any one of claims 1-8.
A computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the signal detection and capture method according to any one of claims 1-8 is realized.