Asynchronous network searching method, system and device for frequency hopping ad hoc network and medium

Abstract

The invention provides an asynchronous network search method, system and device for a frequency hopping ad hoc network and a medium. The method comprises the following steps: determining a network scale M of the frequency hopping ad hoc network and a time error N between network nodes; determining a corresponding synchronous frequency point Ftod in combination with the original data key PK and a preset operation rule, and returning to the first N-1 minutes to obtain N synchronous frequency points; uniformly setting N + 1 synchronous time slots in each subframe through the time error N, and selecting a continuous time slot between two synchronous time slots as an asynchronous network detection time slot; and based on the asynchronous network detection time slot, sending and receiving of broadcast messages are carried out by using the synchronous frequency point, and asynchronous network discovery and time synchronization are completed. According to the method, through time error and synchronization frequency point design, efficient network discovery and time synchronization are realized, different scene requirements can be adapted, time delay fluctuation is reduced through a detection and backspacing mechanism, and network real-time performance and stability are improved.

Description

Technical Field

[0001] This invention relates to the field of frequency-hopping ad hoc networks, and more specifically to an asynchronous network search method, system, device, and medium for frequency-hopping ad hoc networks. Background Technology

[0002] Frequency-hopping ad hoc networks are a widely used network technology in the field of wireless communication. By transmitting data by hopping between different frequencies, they can effectively resist narrowband interference and are suitable for scenarios such as military communications, the Internet of Things, and emergency communications. The core advantages of frequency-hopping ad hoc networks lie in their anti-interference capabilities and stealth, but they also face challenges in time synchronization between network nodes and asynchronous network discovery, especially in scenarios of network splitting or subnet merging.

[0003] Traditional frequency-hopping ad hoc networks typically employ a wait-and-search algorithm for time synchronization. This involves the receiver maintaining a fixed frequency while the transmitter continuously hops frequencies until they match. While simple, this method suffers from significant efficiency issues. First, the synchronization time of the wait-and-search algorithm is directly proportional to the time error between network nodes; the larger the time error, the longer the synchronization time, leading to a substantial increase in communication latency. Second, with a large number of nodes or a complex network topology, the success rate of the wait-and-search algorithm drops drastically, making synchronization failures more likely.

[0004] Furthermore, current asynchronous network discovery technologies primarily rely on random frequency hopping and fixed-frequency probes, lacking a systematic frequency allocation and time slot management mechanism. This random probe method leads to instability in the asynchronous network discovery process, making it prone to probe failures or communication interruptions. For example, when the frequency hopping sequences of two asynchronous networks do not match, nodes may be unable to discover each other for an extended period, resulting in network fusion failure. Moreover, the impact of time errors between network nodes on the probe process is not effectively addressed; nodes with larger time errors may not receive broadcast messages from each other on overlapping frequencies, further reducing the success rate of asynchronous network discovery.

[0005] Therefore, how to design an asynchronous network search method for frequency-hopping ad hoc networks that can achieve efficient time synchronization and asynchronous network discovery, while reducing communication latency fluctuations and improving network stability and real-time performance, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides an asynchronous network search method for frequency hopping ad hoc networks, which can accurately determine the synchronization frequency point, improve search efficiency, reduce resource waste, and at the same time ensure the reliability and stability of the network.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an asynchronous network search method for frequency-hopping ad hoc networks, comprising the following steps:

[0009] S1. Based on relevant design specifications, determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes;

[0010] S2. Based on the current local time of the network node, combined with the original data key PK and the preset operation rules, determine the corresponding synchronization frequency point Ftod, and backtrack to the previous N-1 minutes to obtain N synchronization frequency points;

[0011] S3. Using the time error N, N+1 synchronization time slots are uniformly set in each subframe, and the consecutive time slots between two synchronization time slots are selected as asynchronous network detection time slots;

[0012] S4. Based on the asynchronous network detection time slot, broadcast messages are sent and received using the synchronization frequency point to complete asynchronous network discovery and time synchronization.

[0013] Furthermore, S1 includes:

[0014] S11. Based on the geographical location, communication capabilities, and expected network coverage of the frequency hopping self-organizing network, determine the maximum number of network nodes M through simulation or actual testing, and optimize the value of M according to the network topology to adapt to different application scenarios.

[0015] S12. Use a clustering algorithm to group the network nodes in the frequency-hopping ad hoc network; wherein the number of network nodes in each group does not exceed [number missing]. F is the preset grouping factor;

[0016] S13. Based on the time synchronization error requirements of frequency hopping ad hoc networks, time drift is evaluated using a statistical analysis algorithm to obtain the time error N between network nodes; where the unit of time error N is minutes.

[0017] Furthermore, S2 includes:

[0018] S21. Define the current local time of the network node as TODH in minutes;

[0019] S22. Combine the original data key PK and generate the synchronization frequency point Ftod corresponding to the current local time through hash operation rules;

[0020] S23. Go back N-1 minutes from the current time and calculate the corresponding synchronization frequency point for each minute to obtain a set of N synchronization frequency points [Ftod1, Ftod2, Ftod3, ..., FtodN]; where Ftod1 is the synchronization frequency point of the current time and FtodN is the synchronization frequency point of the previous N-1 minutes.

[0021] Furthermore, S3 includes:

[0022] S31. Based on the time error N, N+1 synchronization time slots are evenly set in each subframe to ensure that the intervals between synchronization time slots are equal.

[0023] S32. Select a consecutive time slot between two synchronous time slots as an asynchronous network detection time slot for the discovery and detection of asynchronous networks;

[0024] S33. Broadcast the time allocation information of the synchronous time slot and the asynchronous network probe time slot to all network nodes in the network to ensure that the network nodes can perform synchronization and probe operations according to the time slot table.

[0025] Furthermore, S4 includes:

[0026] When a network node gains the right to send a broadcast message, each network node takes turns using the synchronization frequency points in [Ftod1, Ftod2, Ftod3, ..., FtodN] to send the broadcast message; whereby each network node uses the synchronization time slots within N consecutive subframes to send the broadcast message each time, which contains N*(N+1) synchronization time slots;

[0027] When a network node does not have the right to send broadcast messages, it enters an asynchronous network probing state. Each network node takes turns using the synchronization frequencies Ftod1 and FtodN to receive broadcast messages in each probing period; the probing period contains M*N subframes.

[0028] Furthermore, the broadcast message includes the timestamp and synchronization frequency information of this network for time synchronization between asynchronous networks.

[0029] Furthermore, when a network node does not have the authority to send broadcast messages, this also includes:

[0030] If a network node fails to receive a broadcast message, a fallback mechanism is initiated, gradually increasing the probe interval until a broadcast message is successfully received or the preset maximum number of retries is reached.

[0031] Secondly, the present invention provides an asynchronous network search system for frequency-hopping ad hoc networks, comprising:

[0032] Network parameter determination module: used to determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes based on relevant design specifications;

[0033] Synchronization frequency point calculation module: used to determine the corresponding synchronization frequency point Ftod based on the current local time of the network node, combined with the original data key PK and preset calculation rules, and backtrack to the previous N-1 minutes to obtain N synchronization frequency points;

[0034] Synchronization slot setting module: used to uniformly set N+1 synchronization slots in each subframe based on the time error N, and select consecutive slots between two synchronization slots as asynchronous network detection slots;

[0035] Asynchronous network discovery and time synchronization module: used to send and receive broadcast messages based on the asynchronous network detection time slot and the synchronization frequency point, thereby completing asynchronous network discovery and time synchronization.

[0036] Thirdly, the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described asynchronous network search method for frequency-hopping ad hoc networks.

[0037] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described asynchronous network search method.

[0038] The descriptions of the second to fourth aspects of this invention can be referred to the detailed description of the first aspect; and the beneficial effects described in the second to fourth aspects can be referred to the analysis of the beneficial effects of the first aspect, which will not be repeated here.

[0039] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. This method generates a synchronization frequency point by combining the current local time of the network node and the original data key PK, and uses the time error N to uniformly set the synchronization time slot and asynchronous network detection time slot in each subframe. This enables network nodes to complete asynchronous network discovery and time synchronization in a short time, significantly reducing the time overhead of traditional wait-and-search algorithms and improving the real-time performance and efficiency of network discovery.

[0041] 2. The network size M is determined through simulation or actual testing, and network nodes are grouped using clustering algorithms, enabling flexible adaptation to the needs of different application scenarios. Simultaneously, time drift is evaluated using statistical analysis algorithms to determine the time error N between nodes, ensuring stable network operation under different time synchronization error requirements and enhancing the system's adaptability and robustness.

[0042] 3. An asynchronous network probing time slot and backoff mechanism were also designed. When a network node does not have the right to send a broadcast message, it can take turns using the synchronization frequencies Ftod1 and FtodN to receive messages. If a synchronization message is not successfully received, the backoff mechanism is activated, gradually increasing the probing interval until successful reception or the maximum number of retries is reached. This effectively reduces communication latency fluctuations, improves the reliability of asynchronous network probing, and ensures stable network operation in complex environments. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0044] Figure 1 A flowchart of an asynchronous network search method for a frequency-hopping ad hoc network provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram illustrating the process of sending and receiving broadcast messages using a synchronization frequency point, provided as an embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram illustrating a method for transmitting broadcast messages using a synchronization frequency point, provided in an embodiment of the present invention.

[0047] Figure 4 This is a schematic diagram of the asynchronous network search process in an emergency communication network provided in an embodiment of the present invention;

[0048] Figure 5 A framework diagram of an asynchronous network search system for a frequency-hopping ad hoc network is provided in an embodiment of the present invention.

[0049] Figure 6 A schematic diagram of the electronic device structure is provided for an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The asynchronous network search method provided in this application can be applied to an asynchronous network search server. The asynchronous network search server can be hardware or software. When the asynchronous network search server is hardware, it can be implemented as a distributed server cluster providing asynchronous network search services, or it can be implemented as a single server. When the asynchronous network search server is software, it can be installed on the servers listed above. It can be implemented as multiple software programs or software modules, or it can be implemented as a single software program or software module; no specific limitations are made here.

[0052] Example 1;

[0053] like Figure 1 As shown, this embodiment provides an asynchronous network search method for frequency-hopping ad hoc networks, including the following steps:

[0054] S1. Based on relevant design specifications, determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes;

[0055] S2. Based on the current local time of the network node, combined with the original data key PK and the preset operation rules, determine the corresponding synchronization frequency point Ftod, and backtrack to the previous N-1 minutes to obtain N synchronization frequency points;

[0056] S3. Using the time error N, N+1 synchronization time slots are uniformly set in each subframe, and the consecutive time slots between two synchronization time slots are selected as asynchronous network detection time slots;

[0057] S4. Based on the asynchronous network detection time slot, broadcast messages are sent and received using the synchronization frequency point to complete asynchronous network discovery and time synchronization.

[0058] This method generates a synchronization frequency point by combining the current local time of network nodes and the original data key, and uses time errors to uniformly set synchronization time slots and asynchronous network detection time slots, achieving efficient time synchronization and network discovery. Its flexible network scalability and time error adaptability can optimize network performance according to different application scenarios. At the same time, through a reliable asynchronous network detection and backoff mechanism, it reduces communication latency fluctuations and significantly improves the real-time performance, stability, and robustness of network discovery.

[0059] The following provides a further detailed explanation of each step in the above method;

[0060] Furthermore, S1 includes:

[0061] S11. Based on the geographical location, communication capabilities, and expected network coverage of the frequency hopping ad hoc network, determine the maximum number of network nodes M through simulation or actual testing, and optimize the value of M according to the network topology to adapt to different application scenarios. For example, in urban environments, due to building obstruction and multipath effects, the network coverage is small, and the value of M may need to be appropriately reduced; while in open areas, the value of M can be appropriately increased.

[0062] S12. Use a clustering algorithm to group the network nodes in the frequency-hopping ad hoc network; wherein the number of network nodes in each group does not exceed [number missing]. F is a preset grouping factor; in practice, nodes can be clustered based on their geographical location, communication load, or energy consumption to ensure that the number of nodes in each group does not exceed the preset grouping factor (e.g., 10 nodes), thereby optimizing network load balancing.

[0063] S13. Considering the time synchronization error requirements of frequency-hopping ad hoc networks, a statistical analysis algorithm is used to evaluate time drift and obtain the time error N between network nodes; where the unit of time error N is minutes. This statistical analysis can use a sliding window mean or Kalman filter to evaluate time drift, and model based on historical time error data to predict future time errors N, ensuring the accuracy of time synchronization.

[0064] Furthermore, S2 includes:

[0065] S21. Define the current local time of the network node as TODH in minutes; it can obtain high-precision time through GPS or Network Time Protocol (NTP) to ensure that the time base of all nodes is consistent.

[0066] S22. Combining the original data key PK, the synchronization frequency point Ftod corresponding to the current local time is generated through hash operation rules. The hash operation rules here use encrypted hash algorithms such as SHA-256, taking TODH and PK as inputs to generate a unique synchronization frequency point, ensuring the randomness and security of the frequency point.

[0067] S23. Go back N-1 minutes from the current time and calculate the corresponding synchronization frequency point for each minute to obtain a set of N synchronization frequency points [Ftod1, Ftod2, Ftod3, ..., FtodN]; where Ftod1 is the synchronization frequency point of the current time and FtodN is the synchronization frequency point of the previous N-1 minutes.

[0068] Furthermore, S3 includes:

[0069] S31. Based on the time error N, N+1 synchronization time slots are evenly set in each subframe to ensure that the interval between synchronization time slots is equal. For example, if the subframe length is 1 second and the time error N is 5 minutes, then the interval between each synchronization time slot is 1 second / (5+1) = 166.67 milliseconds.

[0070] S32. Select a consecutive time slot between two synchronous time slots as an asynchronous network detection time slot for the discovery and detection of asynchronous networks;

[0071] S33. Broadcast the time allocation information for synchronous and asynchronous network probe time slots to all network nodes within the network to ensure that network nodes can perform synchronization and probe operations according to the time slot table. In specific implementation, the time slot table can be sent through the control channel or broadcast channel to ensure that all nodes can operate according to a unified time slot table.

[0072] Furthermore, such as Figure 2 The diagram illustrates the process of sending and receiving broadcast messages using synchronous frequencies in an asynchronous network environment, as well as the allocation and usage of time slots within different subframes. The diagram uses yellow, green, and blue colors to mark synchronous TOD time slots, communication time slots, and asynchronous network probe time slots, respectively. Specifically, S4 includes:

[0073] When a network node gains the right to send a broadcast message, each network node takes turns using the synchronization frequency points in [Ftod1, Ftod2, Ftod3, ..., FtodN] to send the broadcast message; whereby each network node uses the synchronization time slots within N consecutive subframes to send the broadcast message each time, which contains N*(N+1) synchronization time slots;

[0074] like Figure 3 As shown, it can be represented by a matrix of frequency hopping sequences, where the elements of the rows and columns are arranged cyclically from F1 to Fn. This arrangement simulates the transmission method of synchronization frequencies on synchronization time slots. Each frequency is transmitted sequentially, and after reaching the last frequency, it cycles back to the first frequency, forming a periodic transmission pattern.

[0075] When a network node does not have the right to send broadcast messages, it enters an asynchronous network probing state. Each network node takes turns using the synchronization frequencies Ftod1 and FtodN to receive broadcast messages in each probing period; the probing period contains M*N subframes.

[0076] In this implementation, a round-robin scheduling algorithm is used to allocate sending permissions, ensuring that each node has a chance to send within N consecutive subframes. Specifically, node A sends a message using Ftod1 in the first subframe, node B sends a message using Ftod2 in the second subframe, and so on. When a node does not have sending permission, it enters an asynchronous network probing state, taking turns using Ftod1 and FtodN to receive messages. In addition, a timer is used to control the probing period, ensuring that nodes can cover all possible synchronization frequencies within each probing period.

[0077] Furthermore, the broadcast message includes the timestamp and synchronization frequency information of this network for time synchronization between asynchronous networks.

[0078] After parsing the broadcast message, the receiving node calculates the time error based on the timestamp and adjusts its local frequency hopping sequence according to the synchronization frequency information. If the receiving node finds a time error of 2 minutes, it can adjust its local time forward or backward by 2 minutes to complete time synchronization.

[0079] Furthermore, when a network node does not have the authority to send broadcast messages, this also includes:

[0080] If a network node fails to receive a broadcast message, a fallback mechanism is initiated, gradually increasing the probe interval until a broadcast message is successfully received or the preset maximum number of retries is reached.

[0081] The initial detection interval is 1 second. If the detection fails, the detection interval is increased to 2 seconds, 4 seconds, 8 seconds, until the preset maximum number of retries (e.g., 5 times) is reached. It can effectively deal with interference or signal attenuation in the network environment, avoid resource waste caused by frequent detection, and improve the success rate of detection.

[0082] This embodiment provides an asynchronous network search method for frequency-hopping ad hoc networks. It combines an efficient clustering algorithm, accurate time drift assessment, and flexible synchronization frequency calculation, ensuring efficient and stable time synchronization and network discovery even in unstable network environments. Furthermore, a backoff mechanism optimizes the probe interval, further improving communication efficiency and reliability, and adapting to the needs of different application scenarios.

[0083] Example 2;

[0084] This embodiment employs frequency-hopping ad hoc networking technology to construct a temporary emergency communication network for post-earthquake rescue operations. Post-earthquake communication infrastructure may be damaged, making the rapid establishment of a reliable communication network crucial for the success of rescue efforts. This emergency communication network needs to be able to quickly adapt to changing environments and provide stable and efficient information exchange capabilities.

[0085] like Figure 4 As shown, the specific implementation steps include:

[0086] 1) Determine the network size and time error;

[0087] First, based on the specific circumstances of the disaster area, such as geographical features and the expected number of rescue teams, the maximum number of network nodes M was determined to be 500 using simulation tools. Considering the complex and variable environment of the disaster area, especially the significant building obstruction and multipath effects in urban ruins, as well as the impact of mountainous terrain on signal propagation, the network topology was adjusted to adapt to different application scenarios. In urban centers, where dense buildings limit signal propagation, the network node density was appropriately reduced; while in open areas, the node density was increased to expand coverage. Furthermore, a clustering algorithm was used to divide these nodes into several groups, each with no more than 50 nodes, optimizing network load balancing and ensuring good communication quality even under poor network conditions.

[0088] Furthermore, the time synchronization requirements between network nodes were assessed. Considering potential signal interference and other uncertainties caused by earthquakes, a time error N was set at 3 minutes. To accurately assess time drift, two statistical analysis methods—sliding window mean and Kalman filtering—were used to process historical time error data and predict future time errors N. This not only ensured the accuracy of time synchronization but also enabled the network to better adapt to constantly changing external environments. Effective management of time drift improved the overall network's time synchronization accuracy, thereby enhancing the reliability of information transmission.

[0089] 2) Generate synchronization frequency points;

[0090] Each network node generates a corresponding synchronization frequency point Ftod based on its local time TODH (obtained from GPS or Network Time Protocol NTP) and the original data key PK, using the SHA-256 hash algorithm. This ensures the randomness and security of the frequency point, preventing unauthorized access. Simultaneously, using a cryptographic hash algorithm effectively avoids frequency collisions, improving network resource utilization.

[0091] Furthermore, going back 2 minutes (i.e., N-1 minutes), three synchronization frequencies [Ftod1, Ftod2, Ftod3] are calculated. This process allows nodes to effectively switch frequencies within a certain time range, increasing the network's flexibility and robustness. When a node encounters interference or signal loss while attempting to connect, it can quickly switch to another pre-calculated synchronization frequency, reducing the time required to re-establish a connection and significantly improving communication efficiency and reliability.

[0092] 3) Set synchronous and asynchronous network probe time slots;

[0093] Based on the time error N, four synchronization time slots are evenly distributed in each subframe (since N=3) to ensure that the intervals between each synchronization time slot are equal. This is to ensure that all nodes can complete the necessary synchronization operations within the predetermined time period, such as sending heartbeat packets or confirming message reception status.

[0094] A consecutive time slot between two synchronous time slots is selected as the asynchronous network probe time slot for the discovery and detection of asynchronous networks. Furthermore, the time allocation information for both the synchronous and asynchronous network probe time slots is broadcast to all nodes within the network, ensuring they can operate according to a unified time slot table.

[0095] 4) Sending and receiving broadcast messages for network discovery and time synchronization;

[0096] When a node gains transmission privileges, it broadcasts messages in turn using the synchronization frequencies [Ftod1, Ftod2, Ftod3] over three consecutive subframes. This achieves efficient information transmission and also helps other nodes complete the time synchronization process. By fairly allocating transmission privileges through a round-robin scheduling algorithm, it ensures that each node has the opportunity to participate in network activities.

[0097] If sending permission is not granted, the node enters asynchronous network probing mode, using Ftod1 and Ftod3 to receive messages. In this mode, the node attempts to listen for information from other nodes to update its own network status in a timely manner. When encountering poor network conditions or signal loss, a fallback mechanism is activated, gradually increasing the probing interval until a broadcast message is successfully received or the preset maximum number of retries is reached.

[0098] This embodiment uses frequency hopping ad hoc networking technology to construct a temporary emergency communication network. By determining the network size and time error, generating synchronization frequency points, setting synchronous and asynchronous time slots, and sending / receiving broadcast messages, it can quickly adapt to the disaster area environment, provide stable and efficient information exchange capabilities, and ensure the successful conduct of earthquake rescue operations.

[0099] Example 3;

[0100] like Figure 5 As shown, this embodiment provides an asynchronous network search system for frequency-hopping ad hoc networks, including:

[0101] Network parameter determination module: used to determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes based on relevant design specifications;

[0102] Synchronization frequency point calculation module: used to determine the corresponding synchronization frequency point Ftod based on the current local time of the network node, combined with the original data key PK and preset calculation rules, and backtrack to the previous N-1 minutes to obtain N synchronization frequency points;

[0103] Synchronization slot setting module: used to uniformly set N+1 synchronization slots in each subframe based on the time error N, and select consecutive slots between two synchronization slots as asynchronous network detection slots;

[0104] Asynchronous network discovery and time synchronization module: used to send and receive broadcast messages based on the asynchronous network detection time slot and the synchronization frequency point, thereby completing asynchronous network discovery and time synchronization.

[0105] This embodiment provides an asynchronous network search system for frequency-hopping self-organizing networks. The system achieves efficient and stable network search and time synchronization functions through modules such as network parameter determination, synchronization frequency point calculation, synchronization time slot setting, asynchronous network discovery and time synchronization.

[0106] Example 4;

[0107] like Figure 6 As shown, this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described asynchronous network search method for frequency-hopping ad hoc networks.

[0108] Example 5;

[0109] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the asynchronous network search method described above.

[0110] In the embodiments provided in this application, it should be understood that the disclosed methods, systems, devices, and media can be implemented in other ways. The embodiments of methods, systems, devices, and media described above are merely illustrative. For example, the division of modules or units is only a logical functional division, and there may be other division methods in actual implementation. Each functional unit can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0111] The units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0112] Computer programs include computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory, random access memory, electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0113] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for asynchronous network search of a frequency hopping ad hoc network, characterized in that, The method comprises the following steps: S1, according to the relevant design index, determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes; S2, based on the current local time of the network node, combined with the original data key PK and the preset operation rule to determine the corresponding synchronization frequency point Ftod, and back to the previous N-1 minutes to obtain N synchronization frequency points; S3, through the time error N, evenly set N+1 synchronization slots in each subframe, and select the continuous slots between the two synchronization slots as the asynchronous network detection slots; S4, based on the asynchronous network detection slots, use the synchronization frequency point to send and receive broadcast messages, complete the asynchronous network discovery and time synchronization.

2. The method of claim 1, wherein the method further comprises: The S1 comprises: S11, based on the geographical position, communication ability and expected network coverage range of the frequency hopping ad hoc network, determine the maximum number of network nodes M through simulation or actual test, and optimize the M value according to the network topology structure to adapt to different application scenarios; S12, grouping network nodes in the frequency hopping ad hoc network by using a clustering algorithm; wherein the number of network nodes in each group is not more than F a preset grouping factor; S13, combined with the time synchronization error demand of the frequency hopping ad hoc network, evaluate the time drift through statistical analysis algorithm, and obtain the time error N between network nodes; wherein, the unit of time error N is minute.

3. The method of claim 1, wherein the method further comprises: The S2 comprises: S21, define the current local time of the network node as TODH in minute unit; S22, combined with the original data key PK, generate the synchronization frequency point Ftod corresponding to the current local time through the hash operation rule; S23, from the current time, back to the previous N-1 minutes, calculate the synchronization frequency point corresponding to each minute, and obtain a group of N synchronization frequency points [Ftod1, Ftod2, Ftod3, …, FtodN]; wherein, Ftod1 is the synchronization frequency point of the current time, and FtodN is the synchronization frequency point of the previous N-1 minutes.

4. The method of claim 1, wherein the method further comprises: The S3 comprises: S31, according to the time error N, evenly set N+1 synchronization slots in each subframe, ensure that the interval between the synchronization slots is equal; S32, select the continuous slots between the two synchronization slots as the asynchronous network detection slots, which are used for the discovery and detection of the asynchronous network; S33, broadcast the time allocation information of the synchronization slots and the asynchronous network detection slots to all network nodes in the network, ensure that the network nodes can perform synchronization and detection operation according to the time slot table.

5. The method of claim 1, wherein the method further comprises: The S4 comprises: When the network node obtains the right to send the broadcast message, each network node uses the synchronization frequency point in [Ftod1, Ftod2, Ftod3, …, FtodN] to send the broadcast message in turn; wherein, each network node uses the synchronization slots in the continuous N subframes to send the broadcast message each time, which contains N*(N+1) synchronization slots; When the network node does not obtain the right to send the broadcast message, enter the asynchronous network detection state, and each network node uses the synchronization frequency points Ftod1 and FtodN to receive the broadcast message in each detection period in turn; wherein, the detection period contains M*N subframes.

6. The method of claim 1, wherein the method further comprises: The broadcast message contains the timestamp and synchronization frequency point information of the network, which is used for the time synchronization between the asynchronous networks.

7. The asynchronous network search method of a frequency hopping ad hoc network according to claim 6, wherein, When the network node does not obtain the right to send the broadcast message, it also comprises: If the network node fails to successfully receive the broadcast message, a fallback mechanism is started, gradually increasing the probe interval time until the broadcast message is successfully received or a preset maximum number of retries is reached.

8. An asynchronous network search system for a frequency hopping ad hoc network, characterized by The method comprises the following steps: The network parameter determination module is configured to determine the network size M of the frequency hopping ad hoc network and the time error N between network nodes according to relevant design indexes; The synchronization frequency point calculation module is configured to determine the corresponding synchronization frequency point Ftod based on the current local time of the network node, in combination with the original data key PK and a preset operation rule, and to obtain N synchronization frequency points by falling back to the previous N-1 minutes; The synchronization time slot setting module is configured to uniformly set N+1 synchronization time slots in each subframe through the time error N, and to select the continuous time slots between two synchronization time slots as asynchronous network probe time slots; The asynchronous network discovery and time synchronization module is configured to perform the sending and receiving of the broadcast message based on the asynchronous network probe time slots and using the synchronization frequency points, and to complete the asynchronous network discovery and time synchronization.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the asynchronous network search method of the frequency hopping ad hoc network according to any one of claims 1 to 7.

10. A computer readable storage medium, the storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the asynchronous network search method of the frequency hopping ad hoc network according to any one of claims 1 to 7.

Images