Signal synchronization method and device of wireless ad hoc network, storage medium and node

Abstract

The invention discloses a signal synchronization method and device of a wireless ad hoc network, a storage medium and a node, and relates to the technical field of communication, the wireless ad hoc network comprises a receiving node and a sending node, and the receiving node can execute the following steps: receiving a data packet sent by the sending node; obtaining a first receiving sequence from the data packet by adopting a sliding window with a first length; performing frequency domain cross-correlation calculation analysis on the first receiving sequence and a local sequence to obtain a signal rough synchronization point; obtaining a second receiving sequence where the signal rough synchronization point is located by adopting a sliding window with a second length; frequency domain cross-correlation calculation analysis is carried out on the second receiving sequence and the local sequence, a signal starting point is obtained, and the first length is larger than the second length. According to the invention, the signal synchronization accuracy and efficiency of the wireless ad hoc network can be effectively improved.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a signal synchronization method, apparatus, storage medium, and node for a wireless ad hoc network. Background Art

[0002] Taking the UAV ad hoc network combining UAV communication and wireless ad hoc network as an example, relevant ad hoc network protocols usually adopt a fixed preamble sequence structure combining a Short Training field (STF) and a Long Training field (LTF) as the basis for receiving node detection and synchronization. Based on this structure, the receiving node usually finds the signal start point through the autocorrelation operation of the STF sequence in the time domain and the cross-correlation operation of the LTF sequence in the time domain.

[0003] In the current manner, since the length of a single STF sequence is short, it is usually necessary to increase the length of the STF sequence after AGC adjustment to ensure the accuracy of signal detection. However, increasing the length of the STF sequence may cause a large change in its autocorrelation value, so the positioning synchronization accuracy of the signal start point is still limited, and the autocorrelation operation of the STF sequence in the time domain usually requires multiple calculations, resulting in poor positioning synchronization efficiency of the signal start point. Summary of the Invention

[0004] An embodiment of this application provides a signal synchronization solution for a wireless ad hoc network, which can effectively improve the signal synchronization accuracy and efficiency of the wireless ad hoc network.

[0005] The embodiments of this application provide the following technical solutions: According to an embodiment of this application, a signal synchronization method for a wireless ad hoc network, the wireless ad hoc network includes a receiving node and a sending node, the method is applied to the receiving node, and the method includes: receiving a data packet sent by the sending node; obtaining a first received sequence from the data packet by using a sliding window of a first length; performing frequency-domain cross-correlation calculation and analysis on the first received sequence and a local sequence to obtain a rough signal synchronization point; obtaining a second received sequence where the rough signal synchronization point is located by using a sliding window of a second length; performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal start point, where the first length is greater than the second length.

[0006] In some embodiments of this application, the data packet is sent by the sending node according to a combined training sequence frame structure, the combined training sequence frame structure includes a preamble sequence and fixed-length control data, a signal synchronization sequence is configured at the head of the preamble sequence, and the local sequence is a sequence pre-configured to be the same as the signal synchronization sequence.

[0007] In some embodiments of the present application, the length of the signal synchronization sequence is N, the first length is greater than N, and the second length is equal to N.

[0008] In some embodiments of the present application, the frequency-domain cross-correlation calculation and analysis of the first received sequence and the local sequence to obtain a rough signal synchronization point includes: performing a Fourier transform of the first received sequence at the first length points to obtain a first transformed sequence; performing a Fourier transform of the local sequence at the first length points to obtain a second transformed sequence; performing conjugate point multiplication of the first transformed sequence and the second transformed sequence in the frequency domain to obtain a first conjugate point multiplication sequence; performing an inverse Fourier transform of the first conjugate point multiplication sequence at the first length points to obtain a first calculation result, where the first calculation result is the absolute value in the time domain; determining whether the maximum peak point in the first calculation result is greater than a first predetermined threshold; if so, determining the position of the maximum peak point in the first calculation result as the rough signal synchronization point.

[0009] In some embodiments of the present application, the frequency-domain cross-correlation calculation and analysis of the second received sequence and the local sequence to obtain a signal start point includes: performing a frequency-domain cross-correlation calculation of the second received sequence and the local sequence to obtain a second calculation result; determining whether the maximum peak point in the second calculation result is greater than a second predetermined threshold; if so, determining the signal start point in the data packet according to the position of the maximum peak point in the second calculation result.

[0010] In some embodiments of the present application, determining the signal start point in the data packet according to the position of the maximum peak point includes: intercepting data within a predetermined range before the maximum peak point in the second calculation result from the second calculation result; determining the position of the first point greater than the second predetermined threshold from the beginning to the end in the data within the predetermined range as the signal start point.

[0011] In some embodiments of the present application, performing a frequency-domain cross-correlation calculation of the second received sequence and the local sequence to obtain a second calculation result includes: performing a Fourier transform of the second received sequence at the second length points to obtain a third transformed sequence; performing a Fourier transform of the local sequence at the second length points to obtain a fourth transformed sequence; performing conjugate point multiplication of the third transformed sequence and the fourth transformed sequence in the frequency domain to obtain a second conjugate point multiplication sequence; performing an inverse Fourier transform of the second conjugate point multiplication sequence at the second length points to obtain the second calculation result, where the second calculation result is the absolute value in the time domain.

[0012] In some embodiments of the present application, obtaining the second received sequence where the rough signal synchronization point is located by using a sliding window of a second length includes: retreating a predetermined retreat length from the rough signal synchronization point in the data packet to obtain a retreat point; and taking data from the retreat point by using the sliding window of the second length to obtain the second received sequence.

[0013] In some embodiments of the present application, the predetermined retreat length is greater than the length of the cyclic prefix of an orthogonal frequency division multiplexing symbol.

[0014] According to an embodiment of the present application, a signal synchronization device for a wireless ad-hoc network, where the wireless ad-hoc network includes a receiving node and a transmitting node, the device is applied to the receiving node, and the device includes: a receiving module, configured to: receive a data packet sent by the transmitting node; a first synchronization analysis module, configured to: obtain a first received sequence from the data packet by using a sliding window of a first length; perform a frequency-domain cross-correlation calculation and analysis on the first received sequence and a local sequence to obtain a rough signal synchronization point; a second synchronization analysis module, configured to: obtain a second received sequence where the rough signal synchronization point is located by using a sliding window of a second length; perform a frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal start point, where the first length is greater than the second length.

[0015] According to another embodiment of the present application, a storage medium stores a computer program, and when the computer program is executed by a processor of a node, the node is caused to execute the method described in the embodiments of the present application.

[0016] According to another embodiment of the present application, a node may include: a memory storing a computer program; and a processor reading the computer program stored in the memory to execute the method described in the embodiments of the present application.

[0017] According to another embodiment of the present application, a computer program product or a computer program includes computer instructions stored in a computer-readable storage medium. A processor of a node reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the node to execute the methods provided in the various alternative implementations described in the embodiments of the present application.

[0018] In the signal synchronization method of the wireless ad hoc network according to the embodiments of the present application, the wireless ad hoc network includes a receiving node and a transmitting node. The receiving node may perform: receiving a data packet sent by the transmitting node; obtaining a first received sequence from the data packet by using a sliding window of a first length; performing frequency-domain cross-correlation calculation and analysis on the first received sequence and a local sequence to obtain a rough signal synchronization point; obtaining a second received sequence where the rough signal synchronization point is located by using a sliding window of a second length; and performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal start point, where the first length is greater than the second length.

[0019] In this way of the embodiments of the present application, first, on the one hand, different lengths of sliding windows are used for rough synchronization processing and fine synchronization processing, and the length of the sliding window for rough synchronization processing is greater than the length of the sliding window for fine synchronization processing; on the other hand, frequency-domain cross-correlation calculation and analysis are performed in the frequency domain during rough synchronization processing; the combined effect of these two aspects can effectively reduce the number of calculations of the cross-correlation operation and shorten the signal synchronization detection time. Further, during rough synchronization processing, frequency-domain cross-correlation calculation and analysis are performed with the local sequence in the frequency domain, avoiding a large synchronization error caused by increasing the length of the short training sequence. Therefore, overall, the signal synchronization accuracy and efficiency of the wireless ad hoc network can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 Shows a flowchart of a signal synchronization method for a wireless ad hoc network according to an embodiment of the present application.

[0022] Figure 2 Shows a schematic diagram of sliding data acquisition according to an example of the present application.

[0023] Figure 3 Shows a schematic diagram of the combined training sequence frame structure according to an example of the present application.

[0024] Figure 4 Shows a flowchart of rough synchronization processing according to an embodiment of the present application.

[0025] Figure 5 Shows a flowchart of fine synchronization processing according to an embodiment of the present application.

[0026] Figure 6A block diagram of a signal synchronization device for a wireless ad hoc network according to an embodiment of the present application is shown.

[0027] Figure 7 A block diagram of a node according to an embodiment of the present application is shown. Detailed implementation manners

[0028] The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments provided herein are only used to explain the present disclosure and are not used to limit the present disclosure. In addition, the embodiments provided below are partial embodiments for implementing the present disclosure, rather than all embodiments for implementing the present disclosure. Without conflict, the technical solutions described in the embodiments of the present disclosure can be implemented in any combined manner. It should be noted that, in the embodiments of the present disclosure, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a method or device including a series of elements not only includes those elements expressly recited, but also includes other elements not expressly listed, or further includes elements inherent to the implementation of the method or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional related elements in the method or device including the element (such as steps in a method or units in a device, for example, the unit may be a part of a circuit, a part of a processor, a part of a program or software, etc.). For example, the signal synchronization method for a wireless ad hoc network provided by the embodiments of the present disclosure includes a series of steps, but the signal synchronization method for a wireless ad hoc network provided by the embodiments of the present disclosure is not limited to the recited steps. Similarly, the signal synchronization device for a wireless ad hoc network provided by the embodiments of the present disclosure includes a series of units, but the device provided by the embodiments of the present disclosure is not limited to including the expressly recited units, and may further include units required for obtaining relevant information or processing based on the information. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present disclosure belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. It can be understood that, in the specific implementation manner of the present application, when related data is involved, when the embodiments in the present application are applied to specific products or technologies, user permission or consent is required, and the collection, use and processing of the related data need to comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0029] Figure 1The flowchart of the signal synchronization method of the wireless ad hoc network according to an embodiment of the present application is schematically shown. The wireless ad hoc network includes receiving nodes and transmitting nodes, and the receiving nodes and transmitting nodes can be any nodes in the wireless ad hoc network, such as devices like drones, vehicle-mounted terminals, mobile phones, smart watches, etc. In a specific embodiment of the present application, the nodes in the wireless ad hoc network are specifically drones.

[0030] The receiving nodes in the wireless ad hoc network can execute the steps of the signal synchronization method as Figure 1 shown. As Figure 1 shown, the signal synchronization method of the wireless ad hoc network can include steps S110 to S150.

[0031] Step S110, receiving the data packet sent by the transmitting node; Step S120, obtaining a first received sequence from the data packet by using a sliding window of a first length; Step S130, performing frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence to obtain a rough signal synchronization point; Step S140, obtaining a second received sequence where the rough signal synchronization point is located by using a sliding window of a second length; Step S150, performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain the signal starting point, where the first length is greater than the second length.

[0032] The receiving nodes in the wireless ad hoc network can receive the data packets sent by the transmitting nodes (i.e., the received data 210 as Figure 2 shown).

[0033] The receiving node first performs coarse synchronization processing. Specifically: obtaining a first received sequence from the data packet by using a sliding window of a first length (i.e., the coarse synchronization window 220 as Figure 2 shown), and then performing frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence to obtain a rough signal synchronization point (i.e., the rough synchronization point 230 as Figure 2 shown).

[0034] The receiving node then performs fine synchronization processing. Specifically: obtaining a second received sequence where the rough signal synchronization point is located by using a sliding window of a second length (i.e., the fine synchronization window 240 as Figure 2 shown), and then performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain the signal starting point, where the first length is greater than the second length.

[0035] In this way of the embodiment of the present application, first, on the one hand, different-length sliding windows are adopted for coarse synchronization processing and fine synchronization processing, and the length of the sliding window for coarse synchronization processing is greater than that of the sliding window for fine synchronization processing; on the other hand, frequency-domain cross-correlation calculation and analysis are performed in the frequency domain during coarse synchronization processing; the combined effect of these two aspects can effectively reduce the number of calculations of the cross-correlation operation and shorten the signal synchronization detection time. Further, during coarse synchronization processing, frequency-domain cross-correlation calculation and analysis are performed with the local sequence in the frequency domain to avoid large synchronization errors caused by increasing the length of the short training sequence (STF sequence). Therefore, overall, the signal synchronization accuracy and efficiency of the wireless ad hoc network can be effectively improved.

[0036] The following describes Figure 1 During signal synchronization of the wireless ad hoc network in the embodiment, specific embodiments that are further optional under each step are described.

[0037] In one embodiment, the data packet is sent by the sending node according to the combined training sequence frame structure, the combined training sequence frame structure includes a preamble sequence and fixed-length control data, a signal synchronization sequence is configured at the head of the preamble sequence, and the local sequence is a sequence preconfigured to be the same as the signal synchronization sequence.

[0038] Refer to Figure 3 , in the embodiment of the present application, a new combined training sequence frame structure is further provided. The combined training sequence frame structure includes a preamble sequence 310 and fixed-length control data 320. A signal synchronization sequence 311 is configured at the head of the preamble sequence 310. The preamble sequence 310 may further include a short training sequence (Short Training field, STF) 312 and a long training sequence (Long Training field, LTF) 313. The fixed-length control data 320 may include a signaling field 321, a high-throughput short training sequence (HTSTF) 322, and a high-throughput long training sequence (HTLTF) 323. Among them, in one example, the signal synchronization sequence 311 may specifically be a ZC (Zadoff-Chu) sequence.

[0039] In addition, a local sequence identical to the signal synchronization sequence configured in the sending node is preconfigured locally at the receiving node. Based on this combined training sequence frame structure and this local sequence, signal start point positioning synchronization is performed through the foregoing coarse synchronization processing and fine synchronization processing, which can further improve the signal synchronization accuracy of the wireless ad hoc network, especially under low signal-to-noise ratio and multipath channel conditions.

[0040] In the related art, for the STF sequence, autocorrelation operation is performed, and for the LTF sequence and the local LTF sequence, cross-correlation operation is performed to locate and synchronize the signal starting point. It is very vulnerable to the influence of low signal-to-noise ratio and multipath channel conditions, resulting in poor signal synchronization accuracy.

[0041] Further, in an embodiment, the length of the signal synchronization sequence is N, the first length is greater than N, and the second length is equal to N.

[0042] By setting the length of the signal synchronization sequence to N, setting the first length M1 of the sliding window for coarse synchronization processing to be greater than N, and setting the second length M2 of the sliding window for fine synchronization processing to be N, the signal synchronization accuracy can be further ensured. Among them, in one example, the first length can specifically be equal to 2N.

[0043] In one embodiment, referring to Figure 4 , in step S130, performing frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence to obtain the rough signal synchronization point may include: Step S410, performing Fourier transform of the first received sequence with the first length of points to obtain the first transformed sequence; Step S420, performing Fourier transform of the local sequence with the first length of points to obtain the second transformed sequence; Step S430, performing conjugate point multiplication of the first transformed sequence and the second transformed sequence in the frequency domain to obtain the first conjugate point multiplication sequence; Step S440, performing inverse Fourier transform of the first conjugate point multiplication sequence with the first length of points to obtain the first calculation result, and the first calculation result is the absolute value in the time domain; Step S450, determining whether the maximum peak point in the first calculation result is greater than the first predetermined threshold; Step S460, if yes, determining the position of the maximum peak point in the first calculation result as the rough signal synchronization point.

[0044] In this embodiment, specifically, first, performing Fourier transform of the first received sequence with the first length (M1) of points to obtain the first transformed sequence; performing Fourier transform of the local sequence with the first length (M1) of points to obtain the second transformed sequence; performing conjugate point multiplication of the first transformed sequence and the second transformed sequence in the frequency domain to obtain the first conjugate point multiplication sequence.

[0045] Then, performing inverse Fourier transform of the first conjugate point multiplication sequence with the first length of points to obtain the first calculation result, and this first calculation result is the absolute value in the time domain; determining whether the maximum peak point in the first calculation result is greater than the first predetermined threshold (SS1); if the maximum peak point in the first calculation result is greater than the first predetermined threshold (SS1), then determining the position of the maximum peak point in the first calculation result as the rough signal synchronization point.

[0046] In this way, by performing frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence, the rough synchronization point of the signal can be accurately and efficiently located.

[0047] In one embodiment, obtaining the second received sequence where the rough synchronization point of the signal is located by using a sliding window of the second length may include: Retreating a predetermined retreat length from the rough synchronization point of the signal in the data packet to obtain a retreat point; using a sliding window of the second length to extract data starting from the retreat point to obtain the second received sequence.

[0048] Refer to Figure 2 , after determining the rough synchronization point of the signal through coarse synchronization processing (i.e., the rough synchronization point 230 as shown in Figure 2 ), retreat a predetermined retreat length (i.e., the retreat length Q as shown in Figure 2 ) from the rough synchronization point of the signal in the data packet to obtain a retreat point 250. Then, use a sliding window of the second length to extract data starting from the retreat point to obtain the second received sequence. When the second received sequence intercepted in this way is used for fine synchronization processing, the predetermined retreat length can play the role of a guard interval, so as to further improve the positioning synchronization accuracy of the signal starting point.

[0049] Furthermore, in one embodiment, the predetermined retreat length is greater than the length of the cyclic prefix of the orthogonal frequency division multiplexing (OFDM) symbol. This can further ensure the positioning synchronization accuracy of the signal starting point. Among them, orthogonal frequency division multiplexing (OFDM) is a modulation technology used for digital communication. It divides the data stream into multiple subcarriers for transmission. The orthogonal frequency division multiplexing technology can be used for data packet transmission in wireless ad hoc networks.

[0050] In one embodiment, refer to Figure 5 , in step S150, performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain the signal starting point includes: Step S510, performing frequency-domain cross-correlation calculation on the second received sequence and the local sequence to obtain a second calculation result; Step S520, determining whether the maximum peak point in the second calculation result is greater than a second predetermined threshold; Step S530, if so, determining the signal starting point in the data packet according to the position of the maximum peak point in the second calculation result.

[0051] In this embodiment, specifically, first, perform a frequency-domain cross-correlation calculation on the second received sequence and the local sequence to obtain a second calculation result. Then, determine whether the maximum peak point in the second calculation result is greater than a second predetermined threshold (SS2); if the maximum peak point in the second calculation result is greater than the second predetermined threshold (SS2), determine the signal start point according to the position of the maximum peak point in the second calculation result.

[0052] In this way of performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence, the signal start point can be accurately and efficiently located.

[0053] Furthermore, in one embodiment, determining the signal start point in the data packet according to the position of the maximum peak point includes: Intercept data within a predetermined range before the maximum peak point in the second calculation result from the second calculation result; determine the first point greater than the second predetermined threshold from the beginning to the end in the data within the predetermined range as the signal start point.

[0054] In this embodiment, the position of the maximum peak point in the second calculation result is not directly determined as the signal start point (optionally, in other embodiments, the position of the maximum peak point in the second calculation result can be directly determined as the signal start point). Instead, further intercept data within a predetermined range before the maximum peak point in the second calculation result from the second calculation result, and then traverse each point in the data within the predetermined range from the beginning to the end, and determine the first point greater than the second predetermined threshold traversed from the beginning to the end as the signal start point.

[0055] Due to the multipath effect in the actual communication environment, the sequence selected by the receiving node through the sliding window will inevitably contain other sub-path signals. The final result is that when calculating the frequency-domain cross-correlation between the sequence selected by the sliding window and the local sequence, there will be multiple correlation peaks that meet the judgment conditions. On this basis, consider a special multipath channel situation: the power of the first-path signal is less than the power of other path signals. At this time, the signal start point output by the fine synchronization process is incorrect, which causes inter-symbol interference in the service data domain. In this embodiment, a method for dealing with this special multipath channel is designed. Traverse the correlation values within a certain range of the fine synchronization result (i.e., the maximum peak point in the second calculation result) and independently judge the size relationship with the second predetermined threshold, and finally determine the signal start point. This process can effectively suppress the influence of the multipath effect on the synchronization result and further improve the synchronization accuracy of signal start point location.

[0056] Further, in one embodiment, performing frequency-domain cross-correlation calculation on the second received sequence and the local sequence to obtain a second calculation result may include: performing Fourier transform of the second received sequence with a second length of points to obtain a third transformed sequence; performing Fourier transform of the local sequence with a second length of points to obtain a fourth transformed sequence; performing conjugate point multiplication of the third transformed sequence and the fourth transformed sequence in the frequency domain to obtain a second conjugate point multiplication sequence; performing inverse Fourier transform of the second conjugate point multiplication sequence with a second length of points to obtain a second calculation result, and the second calculation result is the absolute value in the time domain.

[0057] In this embodiment, specifically, first, perform Fourier transform of the second received sequence with a second length (M2) of points to obtain a third transformed sequence; perform Fourier transform of the local sequence with a second length (M2) of points to obtain a fourth transformed sequence; perform conjugate point multiplication of the third transformed sequence and the fourth transformed sequence in the frequency domain to obtain a second conjugate point multiplication sequence. Then, perform inverse Fourier transform of the second conjugate point multiplication sequence with a second length of points (M2) to obtain a second calculation result, and the second calculation result is the absolute value in the time domain. The second calculation result obtained in this way can be used to accurately locate the starting point of the synchronization signal.

[0058] To facilitate better implementation of the signal synchronization method for wireless ad-hoc networks provided in the embodiments of the present application, the embodiments of the present application further provide a signal synchronization device for wireless ad-hoc networks based on the above signal synchronization method for wireless ad-hoc networks. The meanings of the terms are the same as those in the above signal synchronization method for wireless ad-hoc networks, and the specific implementation details can refer to the descriptions in the method embodiments. Figure 6 The block diagram of a signal synchronization device for wireless ad-hoc networks according to an embodiment of the present application is shown.

[0059] The wireless ad-hoc network includes a receiving node and a transmitting node. As Figure 6 shown, the signal synchronization device 600 for wireless ad-hoc networks is applied to the receiving node. The signal synchronization device 600 for wireless ad-hoc networks may include: a receiving module 610 may be used to: receive the data packet sent by the transmitting node; a first synchronization analysis module 620 may be used to: obtain a first received sequence from the data packet using a sliding window of a first length; perform frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence to obtain a rough signal synchronization point; a second synchronization analysis module 630 may be used to: obtain a second received sequence where the rough signal synchronization point is located using a sliding window of a second length; perform frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal starting point, where the first length is greater than the second length.

[0060] In some embodiments of the present application, the data packet is sent by the sending node according to a combined training sequence frame structure, the combined training sequence frame structure includes a preamble sequence and fixed-length control data, a signal synchronization sequence is configured at the head of the preamble sequence, and the local sequence is a pre-configured sequence identical to the signal synchronization sequence.

[0061] In some embodiments of the present application, the length of the signal synchronization sequence is N, the first length is greater than N, and the second length is equal to N.

[0062] In some embodiments of the present application, the first synchronization analysis module 620 may be configured to: perform a Fourier transform of the first received sequence at the first length points to obtain a first transformed sequence; perform a Fourier transform of the local sequence at the first length points to obtain a second transformed sequence; perform a conjugate point multiplication of the first transformed sequence and the second transformed sequence in the frequency domain to obtain a first conjugate point multiplication sequence; perform an inverse Fourier transform of the first conjugate point multiplication sequence at the first length points to obtain a first calculation result, the first calculation result being the absolute value in the time domain; determine whether the maximum peak point in the first calculation result is greater than a first predetermined threshold; if so, determine the position of the maximum peak point in the first calculation result as the rough signal synchronization point.

[0063] In some embodiments of the present application, the second synchronization analysis module 630 may be configured to: perform a frequency domain cross-correlation calculation of the second received sequence and the local sequence to obtain a second calculation result; determine whether the maximum peak point in the second calculation result is greater than a second predetermined threshold; if so, determine the signal start point in the data packet according to the position of the maximum peak point in the second calculation result.

[0064] In some embodiments of the present application, the second synchronization analysis module 630 may be configured to: intercept data within a predetermined range before the maximum peak point in the second calculation result from the second calculation result; determine the position of the first point greater than the second predetermined threshold from the beginning to the end in the data within the predetermined range as the signal start point.

[0065] In some embodiments of the present application, the second synchronization analysis module 630 may be configured to: perform a Fourier transform of the second received sequence at the second length points to obtain a third transformed sequence; perform a Fourier transform of the local sequence at the second length points to obtain a fourth transformed sequence; perform a conjugate point multiplication of the third transformed sequence and the fourth transformed sequence in the frequency domain to obtain a second conjugate point multiplication sequence; perform an inverse Fourier transform of the second conjugate point multiplication sequence at the second length points to obtain the second calculation result, the second calculation result being the absolute value in the time domain.

[0066] In some embodiments of the present application, the second synchronization analysis module 630 may be configured to: back off a predetermined back-off length from the signal rough synchronization point in the data packet to obtain a back-off point; use a sliding window of the second length to extract data starting from the back-off point to obtain the second reception sequence.

[0067] In some embodiments of the present application, the predetermined back-off length is greater than the length of the cyclic prefix of the orthogonal frequency division multiplexing symbol.

[0068] It should be noted that although several modules or units of a device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of the two or more modules or units described above may be embodied in one module or unit. Conversely, the features and functions of one module or unit described above may be further divided and embodied by multiple modules or units.

[0069] In addition, an embodiment of the present application further provides a node, as Figure 7 shown, Figure 7 The block diagram of a node according to an embodiment of the present application is shown. Specifically: The node may include components such as a processor 701 with one or more processing cores and a memory 702 of one or more computer-readable storage media. Those skilled in the art can understand that Figure 7 the node structure shown in does not constitute a limitation on the node, and it may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements. Among them: The processor 701 is the control center of the node, connecting various parts of the entire computer device through various interfaces and lines. By running or executing software programs and / or modules stored in the memory 702, and by calling data stored in the memory 702, it executes various functions of the computer device and processes data, thereby monitoring the node as a whole. Optionally, the processor 701 may include one or more processing cores; preferably, the processor 701 may integrate an application processor and a modulation and demodulation processor. Among them, the application processor mainly processes the operating system, user interfaces, and application programs, etc., and the modulation and demodulation processor mainly processes wireless communication. It can be understood that the above modulation and demodulation processor may not be integrated into the processor 701.

[0070] The memory 702 can be used to store software programs and modules. The processor 701 executes various functional applications and data processing by running the software programs and modules stored in the memory 702. The memory 702 mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the computer device. In addition, the memory 702 can include high-speed random access memory and can also include non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage devices. Accordingly, the memory 702 can also include a memory controller to provide the processor 701 with access to the memory 702.

[0071] Although not shown, the node may further include a display unit, etc., which will not be elaborated here. Specifically, in this embodiment, the processor 701 in the node will load the executable files corresponding to the processes of one or more computer programs into the memory 702 according to the following instructions, and the processor 701 will run the computer programs stored in the memory 702 to implement various functions in the foregoing embodiments of the present application.

[0072] For example, the processor 701 may execute the following steps: Receive the data packet sent by the sending node; obtain a first reception sequence from the data packet using a sliding window of a first length; perform frequency-domain cross-correlation calculation and analysis on the first reception sequence and the local sequence to obtain a rough signal synchronization point; obtain a second reception sequence where the rough signal synchronization point is located using a sliding window of a second length; perform frequency-domain cross-correlation calculation and analysis on the second reception sequence and the local sequence to obtain a signal start point, where the first length is greater than the second length.

[0073] Those of ordinary skill in the art can understand that all or part of the steps in the above-described various methods can be completed by a computer program or by controlling relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0074] Therefore, an embodiment of the present application further provides a storage medium in which a computer program is stored, and the computer program can be loaded by a processor to execute the steps in any one of the methods provided by the embodiments of the present application.

[0075] Among them, the storage medium may be a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc.

[0076] Since the computer program stored in the storage medium can execute the steps in any of the methods provided in the embodiments of the present application, the beneficial effects achievable by the methods provided in the embodiments of the present application can be realized. For details, refer to the previous embodiments and will not be elaborated here.

[0077] After considering the specification and practicing the disclosed embodiments herein, those skilled in the art will readily conceive of other implementations of the present application. The present application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application.

[0078] It should be understood that the present application is not limited to the embodiments described above and shown in the drawings, but various modifications and changes can be made without departing from its scope.

Claims

1. A signal synchronization method for a wireless ad hoc network, characterized in that, The wireless ad hoc network includes receiving nodes and sending nodes, and the method is applied to the receiving nodes. The method includes: Receiving a data packet sent by the sending node; Obtaining a first received sequence from the data packet using a sliding window of a first length; Performing frequency-domain cross-correlation calculation and analysis on the first received sequence and a local sequence to obtain a rough signal synchronization point; Obtaining a second received sequence where the rough signal synchronization point is located using a sliding window of a second length; Performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal starting point, where the first length is greater than the second length.

2. The method according to claim 1, wherein The data packet is sent by the sending node according to a combined training sequence frame structure, and the combined training sequence frame structure includes a preamble sequence and fixed-length control data. A signal synchronization sequence is configured at the head of the preamble sequence, and the local sequence is a pre-configured sequence identical to the signal synchronization sequence.

3. The method according to claim 2, wherein The length of the signal synchronization sequence is N, the first length is greater than N, and the second length is equal to N.

4. The method according to claim 1, characterized in that The performing frequency-domain cross-correlation calculation and analysis on the first received sequence and the local sequence to obtain a rough signal synchronization point includes: Performing a first-length point Fourier transform on the first received sequence to obtain a first transformed sequence; Performing a first-length point Fourier transform on the local sequence to obtain a second transformed sequence; Performing conjugate point multiplication on the first transformed sequence and the second transformed sequence in the frequency domain to obtain a first conjugate point multiplication sequence; Performing a first-length point inverse Fourier transform on the first conjugate point multiplication sequence to obtain a first calculation result, and the first calculation result is the absolute value in the time domain; Determining whether the maximum peak point in the first calculation result is greater than a first predetermined threshold; If so, determining the position of the maximum peak point in the first calculation result as the rough signal synchronization point.

5. The method according to claim 1, characterized in that, The performing frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal starting point includes: Performing frequency-domain cross-correlation calculation on the second received sequence and the local sequence to obtain a second calculation result; Determining whether the maximum peak point in the second calculation result is greater than a second predetermined threshold; If so, determining the signal starting point in the data packet according to the position of the maximum peak point in the second calculation result.

6. The method according to claim 5, wherein The determining the signal starting point in the data packet according to the position of the maximum peak point includes: Intercepting data within a predetermined range before the maximum peak point in the second calculation result from the second calculation result; Determining the position of the first point greater than the second predetermined threshold from the beginning to the end of the data within the predetermined range as the signal starting point.

7. The method according to claim 5, wherein The performing frequency-domain cross-correlation calculation on the second received sequence and the local sequence to obtain a second calculation result includes: Performing a second-length point Fourier transform on the second received sequence to obtain a third transformed sequence; Performing a second-length point Fourier transform on the local sequence to obtain a fourth transformed sequence; Performing conjugate point multiplication on the third transformed sequence and the fourth transformed sequence in the frequency domain to obtain a second conjugate point multiplication sequence; Perform an inverse Fourier transform of the second conjugate dot product sequence with a second length to obtain the second calculation result, which is the absolute value in the time domain.

8. The method according to claim 1, characterized in that, The obtaining of the second received sequence where the rough signal synchronization point is located by using a sliding window with a second length includes: In the data packet, retreat a predetermined retreat length from the rough signal synchronization point to obtain a retreat point; Use the sliding window with the second length to take data starting from the retreat point to obtain the second received sequence.

9. The method according to claim 8, wherein The predetermined retreat length is greater than the length of the cyclic prefix of the orthogonal frequency division multiplexing symbol.

10. A signal synchronization device for a wireless ad hoc network, characterized in that, The wireless ad hoc network includes a receiving node and a transmitting node. The device is applied to the receiving node and includes: A receiving module for receiving the data packet sent by the transmitting node; A first synchronization analysis module for obtaining a first received sequence from the data packet by using a sliding window with a first length; performing a frequency-domain cross-correlation calculation and analysis on the first received sequence and a local sequence to obtain a rough signal synchronization point; A second synchronization analysis module for obtaining a second received sequence where the rough signal synchronization point is located by using a sliding window with a second length; performing a frequency-domain cross-correlation calculation and analysis on the second received sequence and the local sequence to obtain a signal start point, where the first length is greater than the second length.

11. A storage medium, characterized in that, A computer program is stored thereon. When the computer program is executed by the processor of the node, the node executes the method according to any one of claims 1 to 9.

12. A node, characterized in that, It includes: A memory storing a computer program; A processor for reading the computer program stored in the memory to execute the method according to any one of claims 1 to 9.

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