Method and system for dynamically adjusting optimal same frequency point of unmanned aerial vehicle ad hoc network

Abstract

The invention discloses an unmanned aerial vehicle ad hoc network optimal same frequency point dynamic adjustment method, and relates to the technical field of wireless communication, and the method comprises the steps: S1, building a synchronous frequency point candidate library of ad hoc network nodes; s2, periodically acquiring background noise information of each synchronous frequency point of the ad hoc network node in the synchronous frequency point candidate library; s3, acquiring an optimal synchronous frequency point of the ad hoc network node in the current period according to the background noise information of the ad hoc network node; s4, judging whether the channel quality of the ad hoc network nodes in the current period is lower than a threshold value or not, if so, entering the next step, otherwise, returning to the step S2; and S5, switching the synchronous frequency point used by the current ad hoc network node to the optimal synchronous frequency point, and updating the synchronous frequency point candidate library in the step S1. According to the technical scheme provided by the invention, the synchronization frequency point used in the current period is dynamically adjusted according to the channel quality, and the problem that the synchronization frequency point is interfered and data is lost is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to a method and system for dynamically adjusting the optimal co-frequency point of an unmanned aerial vehicle self-organizing network. Background Art

[0002] In drone self-organizing network communication, in order to achieve better anti-interference performance, we usually use frequency hopping mode for communication. The frequency hopping mode stipulates that the sender and receiver have the same frequency hopping sequence to ensure normal communication. Usually we use a certain frequency point of the frequency hopping sequence to transmit synchronization information, and this frequency point is called the synchronization frequency point. The synchronization information contains the most critical information for networking and determines whether the networking is successful. The frequency hopping mode has good anti-interference ability, but the frequency hopping sequence itself is a pseudo-random sequence and cannot be dynamically adjusted according to the time-varying characteristics of the channel; in some scenarios, specific interference will cause the drone to lose connection or even crash. Summary of the invention

[0003] The purpose of this application is to provide a method and system for dynamically adjusting the optimal co-frequency point of a drone self-organizing network, aiming to solve the technical problem that the synchronization frequency of the frequency hopping sequence of the drone self-organizing network cannot adapt to the time variation of the channel.

[0004] To achieve the above purpose, the present application proposes a method for dynamically adjusting the optimal co-frequency point of a drone ad hoc network, the method comprising:

[0005] S1. Establish a candidate library of synchronization frequencies for ad hoc network nodes;

[0006] S2. Periodically obtain the background noise information of each synchronization frequency point in the synchronization frequency point candidate library of the self-organizing network node;

[0007] S3. Obtain the optimal synchronization frequency of the self-organizing network nodes in the current cycle according to the background noise information of the self-organizing network nodes;

[0008] S4. Determine whether the channel quality of the ad hoc network node in the current cycle is lower than the threshold. If so, proceed to the next step, otherwise return to step S2;

[0009] S5. Switch the synchronization frequency currently used by the ad hoc network node to the optimal synchronization frequency, and update the synchronization frequency candidate library of step S1.

[0010] Preferably, the step S2 comprises:

[0011] S21. Calculate the average noise floor of each synchronization frequency point in all nodes of the ad hoc network in the current cycle;

[0012] S22. Obtain the synchronization frequency point with the smallest average background noise in the candidate library in the current cycle;

[0013] S23. Obtain the maximum background noise of the synchronization frequency point with the minimum average background noise in the current cycle.

[0014] Preferably, the step S3 comprises:

[0015] S31. Determine whether the average background noise of the synchronization frequency used in the current cycle is greater than or equal to the minimum average background noise. If so, proceed to the next step;

[0016] S32. Determine whether the maximum background noise of the synchronization frequency point used in the current cycle is greater than the maximum background noise of the synchronization frequency point with the smallest average background noise. If so, the synchronization frequency point with the smallest average background noise is the optimal synchronization frequency point.

[0017] Preferably, the method for updating the synchronization frequency candidate library in step S5 includes:

[0018] The synchronization frequency point used in the current period is recorded in the synchronization frequency point candidate library, and the optimal synchronization frequency point in the synchronization frequency point candidate library is deleted.

[0019] Preferably, step S5 includes:

[0020] When any node in the ad hoc network fails to switch to the optimal synchronization frequency, it switches to the synchronization frequency in the original synchronization frequency candidate library until it re-networks with other nodes.

[0021] A system for dynamically adjusting the optimal co-frequency point of a drone self-organizing network, characterized in that the system comprises a storage module, a central processing module, a plurality of network nodes, and a plurality of network node sub-processing modules:

[0022] S1. The storage module is used to establish a candidate library of synchronization frequencies of ad hoc network nodes;

[0023] S2. The central processing module periodically obtains the background noise information of each synchronization frequency point in the synchronization frequency point candidate library of the self-organizing network node;

[0024] S3. The central processing module obtains the optimal synchronization frequency of the ad hoc network nodes in the current cycle according to the background noise information of the ad hoc network nodes;

[0025] S4. The central processing module determines whether the channel quality of the ad hoc network node in the current cycle is lower than the threshold, if so, proceeds to the next step, otherwise returns to step S2;

[0026] S5. The central processing module switches the synchronization frequency point currently used by the ad hoc network node to the optimal synchronization frequency point, and updates the synchronization frequency point candidate library of step S1.

[0027] Preferably, the step S2 comprises:

[0028] S21. Calculate the average noise floor of each synchronization frequency point in all nodes of the ad hoc network in the current cycle;

[0029] S22. Obtain the synchronization frequency point with the smallest average background noise in the candidate library in the current cycle;

[0030] S23. Obtain the maximum background noise of the synchronization frequency point with the minimum average background noise in the current cycle.

[0031] Preferably, the step S3 comprises:

[0032] S31. The central processing module determines whether the average background noise of the synchronization frequency used in the current cycle is greater than or equal to the minimum average background noise. If so, proceed to the next step;

[0033] S32. The central processing module determines whether the maximum background noise of the synchronization frequency point used in the current cycle is greater than the maximum background noise of the synchronization frequency point with the smallest average background noise. If so, the synchronization frequency point with the smallest average background noise is the optimal synchronization frequency point.

[0034] Preferably, the method for updating the synchronization frequency candidate library in step S5 includes:

[0035] The central processing module records the synchronization frequency point used in the current cycle into the candidate library, and deletes the optimal synchronization frequency point in the candidate library.

[0036] Preferably, step S5 includes:

[0037] The network node sub-processing module is used for switching to a synchronization frequency in the original synchronization frequency candidate library when any node in the self-organizing network fails to switch to the optimal synchronization frequency, until re-networking with other nodes.

[0038] One or more technical solutions proposed in this application have at least the following technical effects:

[0039] Due to the influence of the environment, the anti-interference performance of the nodes in the self-organizing network using different frequencies is different. The noise floor information of all nodes in the self-organizing network in the current cycle environment is statistically analyzed in the cycle, and then the optimal synchronization frequency is selected to prepare for the poor channel quality and the node communication is interfered, so as to adapt to environmental changes;

[0040] Dynamically adjust the synchronization frequency point used in the current cycle according to the channel quality, solving the problem of data loss due to interference with the synchronization frequency point;

[0041] When the node fails to switch the synchronous frequency, the node continuously adjusts its own frequency to re-network with other nodes, thereby improving the dynamic adjustment capability of the node. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0043] Figure 1 This is a flow chart of a system for dynamically adjusting the optimal co-frequency point of a drone self-organizing network according to an embodiment of the present application;

[0044] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0048] The present invention discloses a method and system for dynamically adjusting the optimal co-frequency point of a drone self-organizing network, aiming to solve the technical problem that the synchronization frequency point of a frequency hopping sequence using a frequency hopping mode in a drone self-organizing network cannot adapt to channel time variation.

[0049] Embodiment 1

[0050] like Figure 1 As shown, in order to solve the technical problem that the synchronization frequency of the frequency hopping sequence of the frequency hopping mode of the unmanned aerial vehicle self-organizing network cannot adapt to the time-varying channel, this embodiment provides a dynamic adjustment system for the optimal same frequency point of the unmanned aerial vehicle self-organizing network, including a storage module, a central processing module, a plurality of network nodes, and a plurality of network node sub-processing modules, including the following steps:

[0051] S1. The storage module is used to establish a candidate library of synchronization frequencies of ad hoc network nodes;

[0052] The frequency range supported by the drone self-organizing network equipment (f start ~f end ), and broadband range B w , select appropriate synchronization frequency points by equally dividing the frequency band, and establish a synchronization frequency point candidate library for ad hoc network nodes. The specific method is:

[0053] f i =f start +(i-1))*B w , where i is the index of the candidate frequency point (i=1,2,3,......,N-1),

[0054] (If the divisibility is not exact, round down).

[0055] The synchronized frequency candidate library established in this way can completely cover the entire frequency band, and the number of candidate frequency points selected is the smallest while covering the entire frequency band. The advantage of a small number of candidate frequency points is that the background noise information can be collected quickly, allowing the entire system to respond more quickly.

[0056] S2. The central processing module periodically obtains the background noise information of each synchronization frequency point in the synchronization frequency point candidate library of the self-organizing network node;

[0057] The nodes of the ad hoc network are divided into ground stations and aerial nodes. When obtaining the background noise information of each synchronization frequency in the synchronization frequency candidate library of the ad hoc network node, it is to find other possible better frequencies except the current frequency.

[0058] S21. Calculate the average noise floor of each synchronization frequency point in all nodes of the ad hoc network in the current cycle;

[0059] All nodes N total，j The background noise of the frequency points that need to be scanned when idle. Each node records a background noise value for each frequency point. Each node i scans the background noise at each frequency point and records it as N i，j(Noise floor of node i at the frequency point). Each node sends the noise floor information it scans to the central control system of the ground station through a multicast packet. Therefore, the central control system can obtain the average noise floor of each synchronous frequency point in the candidate library on all nodes (n)

[0060]

[0061] In order to reduce the use of the central processing module's computing power, the synchronization frequency with the lowest average background noise value can be initially selected as the candidate optimal synchronization frequency. Therefore, the synchronization frequency with the lowest average background noise value can be obtained by comparison based on all background noise information. That is:

[0062] S22. Obtain the synchronization frequency point with the smallest average background noise in the candidate library in the current cycle;

[0063] According to the statistics of the average background noise of each synchronization frequency point in the previous step S21, the synchronization frequency point with the smallest average background noise in the candidate library can be obtained.

[0064] S23. Obtain the maximum background noise of the synchronization frequency point with the minimum average background noise in the current cycle.

[0065] S3. The central processing module obtains the optimal synchronization frequency of the self-organizing network node in the current cycle according to the background noise information of the self-organizing network node; specifically includes:

[0066] Because the average noise floor is just an average quantity, when the average noise floor is small, the maximum noise floor corresponding to the average noise floor may be large, and the maximum noise floor largely reflects the poor anti-interference ability of the synchronization frequency. Therefore, even if the average noise floor is small, it cannot be the optimal frequency. Therefore, it is possible to judge whether it is the optimal synchronization frequency from the two dimensions of average noise floor and maximum noise floor.

[0067] S31. The central processing module determines whether the average noise floor of the synchronous frequency point used in the current cycle is greater than or equal to the average noise floor. If so, proceed to the next step;

[0068] S32. The central processing module determines whether the maximum background noise of the synchronization frequency point used in the current cycle is greater than the maximum background noise. If so, the current synchronization frequency point is set as the optimal synchronization frequency point.

[0069] Therefore, when the drone is flying, if there is an interference source, the distance between the aircraft and the interference source must be from far to near, and then from near to far. The corresponding channel quality, such as SNR, will also deteriorate first and then improve. When a minimum SNR threshold is set, if the SNR is less than the minimum threshold, the optimal synchronization frequency will be switched. This can solve the problem of switching the synchronization frequency in advance before approaching the interference source, avoiding the problem of not being able to network due to the interference of the synchronization frequency to the limit. At the same time, if it is not lower than the threshold, although the currently used synchronization frequency is not the optimal synchronization frequency, it will not affect the quality of communication. At the same time, it can avoid frequent switching, frequent networking, and communication quality problems.

[0070] S4. The central processing module determines whether the channel quality SNR of the ad hoc network node in the current cycle is lower than the threshold. If so, proceed to the next step, otherwise return to step S2;

[0071] SNR(dB)=10*log 10 (P s / P n )

[0072] Where: SNR (dB) represents the signal-to-noise ratio, in decibels (dB); P s Represents the average power of the signal; P n Represents the average power of the noise.

[0073] After the device is powered on, the transmit power is fixed, so the SNR is negatively correlated with the noise floor. The larger the noise floor, the smaller the SNR.

[0074] S5. The central processing module switches the synchronization frequency point currently used by the ad hoc network node to the optimal synchronization frequency point, and updates the synchronization frequency point candidate library of step S1. Specifically including:

[0075] The synchronization frequency point used in the current cycle is recorded in the candidate library, and the optimal synchronization frequency point in the candidate library is deleted.

[0076] The actual flight environment has various scenarios, so the switching notification may not be received by the aerial node. Therefore, a node self-recovery strategy is proposed to solve the problem.

[0077] That is, when a node in the self-organizing network fails to switch the optimal frequency, the network node sub-processing module switches to the synchronization frequency of the original synchronization frequency candidate library (that is, the synchronization frequency in the candidate library is not updated because the current networking node uses the synchronization frequency in the original candidate library) until it is re-networked with other nodes.

[0078] For example, if aerial node A does not receive the synchronization signal from the ground node within a certain period, it will automatically shut down the transmission and try different synchronization frequencies until it receives the synchronization signal from the ground station again and rejoins the network.

[0079] It can be seen from the above embodiments that the present application dynamically adjusts the synchronization frequency point used in the current cycle according to the channel quality, thereby solving the problem of data loss due to interference with the synchronization frequency point;

[0080] When the node fails to switch the synchronous frequency, the node continuously adjusts its own frequency to re-network with other nodes, thereby improving the dynamic adjustment capability of the node.

[0081] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for dynamically adjusting the optimal co-frequency point of a drone ad hoc network, characterized in that: The method comprises: S1. Establish a candidate library of synchronization frequencies for ad hoc network nodes; S2. Periodically obtain the background noise information of each synchronization frequency point in the synchronization frequency point candidate library of the self-organizing network node; S3. Obtain the optimal synchronization frequency of the self-organizing network nodes in the current cycle according to the background noise information of the self-organizing network nodes; S4. Determine whether the channel quality of the ad hoc network node in the current cycle is lower than the threshold. If so, proceed to the next step, otherwise return to step S2; S5. Switch the synchronization frequency currently used by the ad hoc network node to the optimal synchronization frequency, and update the synchronization frequency candidate library of step S1.

2. The method for optimal frequency synchronization of a drone ad hoc network as claimed in claim 1, characterized in that: The step S2 comprises: S21. Calculate the average noise floor of each synchronization frequency point in all nodes of the ad hoc network in the current cycle; S22. Obtain the synchronization frequency point with the smallest average background noise in the candidate library in the current cycle; S23. Obtain the maximum background noise of the synchronization frequency point with the minimum average background noise in the current cycle.

3. The method for optimal frequency synchronization of a drone ad hoc network as claimed in claim 1, characterized in that: The step S3 comprises: S31. Determine whether the average background noise of the synchronization frequency used in the current cycle is greater than or equal to the minimum average background noise. If so, proceed to the next step; S32. Determine whether the maximum background noise of the synchronization frequency point used in the current cycle is greater than the maximum background noise of the synchronization frequency point with the smallest average background noise. If so, the synchronization frequency point with the smallest average background noise is the optimal synchronization frequency point.

4. The method for optimal frequency synchronization of a drone ad hoc network as claimed in claim 1, characterized in that: The method for updating the synchronization frequency candidate library in step S5 includes: The synchronization frequency point used in the current period is recorded in the synchronization frequency point candidate library, and the optimal synchronization frequency point in the synchronization frequency point candidate library is deleted.

5. The method for optimal frequency synchronization of a drone ad hoc network as claimed in claim 1, characterized in that: Step S5 includes: When any node in the ad hoc network fails to switch to the optimal synchronization frequency, it switches to the synchronization frequency in the original synchronization frequency candidate library until it re-networks with other nodes.

6. A system for dynamically adjusting the optimal frequency point of a drone self-organizing network, characterized in that: The system includes a storage module, a central processing module, a plurality of network nodes, and a plurality of network node sub-processing modules: S1. The storage module is used to establish a candidate library of synchronization frequencies of ad hoc network nodes; S2. The central processing module periodically obtains the background noise information of each synchronization frequency point in the synchronization frequency point candidate library of the self-organizing network node; S3. The central processing module obtains the optimal synchronization frequency of the ad hoc network nodes in the current cycle according to the background noise information of the ad hoc network nodes; S4. The central processing module determines whether the channel quality of the ad hoc network node in the current cycle is lower than the threshold, if so, proceeds to the next step, otherwise returns to step S2; S5. The central processing module switches the synchronization frequency point currently used by the ad hoc network node to the optimal synchronization frequency point, and updates the synchronization frequency point candidate library of step S1.

7. The system for optimal frequency synchronization dynamic adjustment of unmanned aerial vehicle ad hoc network according to claim 6, characterized in that: The step S2 comprises: S21. Calculate the average noise floor of each synchronization frequency point in all nodes of the ad hoc network in the current cycle; S22. Obtain the synchronization frequency point with the smallest average background noise in the candidate library in the current cycle; S23. Obtain the maximum background noise of the synchronization frequency point with the minimum average background noise in the current cycle.

8. The system for optimal frequency synchronization dynamic adjustment of unmanned aerial vehicle ad hoc network according to claim 6, characterized in that: The step S3 comprises: S31. The central processing module determines whether the average background noise of the synchronization frequency used in the current cycle is greater than or equal to the minimum average background noise. If so, proceed to the next step; S32. The central processing module determines whether the maximum background noise of the synchronization frequency point used in the current cycle is greater than the maximum background noise of the synchronization frequency point with the smallest average background noise. If so, the synchronization frequency point with the smallest average background noise is the optimal synchronization frequency point.

9. The system for optimal frequency synchronization dynamic adjustment of unmanned aerial vehicle ad hoc network according to claim 6, characterized in that: The method for updating the synchronization frequency candidate library in step S5 includes: The central processing module records the synchronization frequency point used in the current cycle into the candidate library, and deletes the optimal synchronization frequency point in the candidate library.

10. The system for optimal frequency synchronization dynamic adjustment of unmanned aerial vehicle ad hoc network according to claim 6, characterized in that: Step S5 includes: The network node sub-processing module is used for switching to a synchronization frequency in the original synchronization frequency candidate library when any node in the self-organizing network fails to switch to the optimal synchronization frequency, until re-networking with other nodes.

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