A wireless communication anti-interference method of avionics system

Abstract

The application relates to the technical field of wireless communication networks, and discloses a wireless communication anti-interference method for an avionics system, which comprises the following steps: nodes in a network autonomously synchronize channel switching based on a shared key and a public time reference; when the public time reference is invalid, a mobile node calibrates a local clock by monitoring the channel switching time of a central node to restore synchronization; the application can avoid interference by synchronizing without real-time signaling, solves the network lockout problem caused by invalid coordination signaling, and ensures the reliability of avionics communication by using the hopping behavior of the network itself as an internal clock beacon to enable the nodes to self-recover and synchronize when an external public time reference is lost.

Description

TECHNICAL FIELD

[0001] The application relates to a wireless communication anti-interference method of an avionics system and belongs to the technical field of wireless communication networks. BACKGROUND

[0002] At present, in applications such as avionics systems that have high requirements for communication continuity, anti-interference capability is required to cope with external interference sources in the channel. At present, an anti-interference technology in this field is a coordinated channel switching, that is, a network center node monitors the communication quality of a current working channel, when it is detected that interference causes the communication quality to decrease beyond a preset threshold, the center node decides a standby channel, and broadcasts control signaling to notify all subordinate mobile nodes to switch to the new standby channel for communication. Even if an advanced cluster cooperation scheme is used, it is still difficult to get rid of the dependence on the communication link itself when dealing with the anti-interference cooperation problem. For example, a wireless communication method for dynamic remote fault-tolerant reconstruction of computing resources of a cluster avionics system is disclosed in Chinese Patent for Invention with the authorization announcement No. CN106961700B. The scheme is constructed based on a fixed time slot time frame structure, a master node broadcasts and sends command messages or remote reconstruction command messages to slave nodes within an allocated active time frame, so as to schedule network resources and handle faults. When the channel quality is good, the resources can be managed, the anti-interference strategy is passive in nature and depends on the signaling reachability. The mechanism operates under the strict premise that the control signaling for coordinating switching must still be reachable when interference occurs.

[0003] The design and operation of this way are that the control signaling for coordinating switching must be reachable when interference occurs. The limitation in specific application scenarios such as complex electromagnetic environments or malicious interference suppression faced by the avionics system is that when an external strong interference source suppresses the current working channel, not only the data link is interrupted, but also the control link used by the center node to send the switching instruction is also invalid. At this time, the center node broadcasts the switching instruction on the disturbed channel according to the plan, but the instruction itself is also disturbed and covered, so that the subordinate mobile nodes cannot correctly receive it. The consequence of the defect of this mechanism is that the mobile nodes still try to reconnect in the original interference channel, while the center node may have switched to a new channel. Finally, the network is logically split and loses lock due to the failure of the attempt, resulting in system communication interruption. In order to cope with this situation, the field has tried to introduce a complex handshake protocol or use an independent out-of-band control channel to deliver the switching instruction. However, this way not only increases the complexity and deployment cost of the system, but also introduces additional dependence on the new communication link, and does not solve the problem of how to realize the synchronous decision of the network nodes without real-time signaling coordination in the case of complete suppression of the working channel and instantaneous communication interruption.

[0004] Therefore, how to provide a wireless communication anti-interference method to get rid of the dependence on real-time coordination signaling, and make all nodes in the network switch to a safe channel synchronously and deterministically in the case of communication interruption caused by strong interference, has become a technical problem to be solved by the present application. SUMMARY

[0005] To solve the problems presented in the background art, the technical solutions of the present application are as follows: A wireless communication anti-interference method of an avionics system, applied to a wireless communication network comprising a center node and at least one mobile node, the method comprising:

[0006] The center node and the mobile node, based on a shared key, independently generate a channel hopping sequence with the same content; acquire a common time reference and share a time slot cycle parameter; and independently periodically execute the following first logic: calculate a current time slot index according to the common time reference and the time slot cycle parameter, and determine a current working channel from the channel hopping sequence according to the current time slot index, and autonomously switch the respective communication channel to the current working channel.

[0007] The method further comprises: the mobile node continuously monitoring the signal quality of the common time reference.

[0008] When the mobile node detects that the signal quality is lower than a preset failure threshold, the mobile node starts a clock resynchronization mode.

[0009] In the clock resynchronization mode, the mobile node executes the following second logic: identifies and determines the occurrence time of channel switching by monitoring the channel switching of the center node on the channel hopping sequence; marks the occurrence time as the starting reference point of a new time slot cycle of the local clock of the mobile node; and resumes the execution of the first logic based on the starting reference point of the new time slot cycle and the time slot cycle parameter.

[0010] Preferably, the method further comprises: defining a fixed anchor channel and an anchor time interval in advance, the period of the anchor time interval being greater than the time slot cycle parameter; the center node suspends the execution of the first logic and autonomously switches to the fixed anchor channel to reside in a time slot cycle when the anchor time interval arrives; and a newly added mobile node listens to and accesses the center node to acquire the shared key and the time slot cycle parameter during the anchor time interval.

[0011] Preferably, the channel hopping sequence is generated by a pair of shared keys and a preset pseudo-random algorithm.

[0012] Preferably, the common time reference is derived from the timestamp of a satellite positioning system.

[0013] Preferably, in the first logic, the step of calculating the current time slot index comprises: acquiring the current time value of the common time reference ; acquiring the sequence length of the channel hopping sequence ; and determining the current time slot index by the following operation: wherein, The duration of the time slot cycle parameter, and have the same time unit, is a floor operation, is a modulo operation.

[0014] Preferably, in the clock resynchronization mode, the step of executing the second logic by the mobile node comprises: the mobile node stops executing the first logic; the mobile node sets its receiver to a scanning mode, and polls the channels in the channel hopping sequence one by one until the signal of the central node is captured on a certain channel; the mobile node continues to reside on the certain channel until the signal of the central node disappears, and the moment when the signal disappears is identified as the occurrence moment.

[0015] Preferably, the method further comprises: the central node determines the interference level by monitoring the packet loss rate or the signal-to-noise ratio in the wireless communication network; and when the interference level is higher than a preset first threshold, the central node broadcasts an instruction to shorten the duration of the time slot cycle parameter.

[0016] Preferably, the time slot cycle parameter is a time slot cycle sequence; the central node and the at least one mobile node generate the time slot cycle sequence corresponding to the sequence number of the channel hopping sequence based on the shared key in addition to the channel hopping sequence; in the first logic, the step of calculating the current time slot index is replaced by iteratively accumulating the time slot cycles in the time slot cycle sequence and comparing with the public time reference to determine the current time slot index.

[0017] Preferably, the newly entered mobile node only knows the fixed anchor channel and the anchor time interval; the newly entered mobile node acquires the public time reference, and when the anchor time interval arrives, waits for and receives the beacon frame of the central node on the fixed anchor channel to initiate the association process.

[0018] Preferably, the method further comprises: when the interference level is lower than a preset second threshold, the central node broadcasts an instruction to lengthen the duration of the time slot cycle parameter.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. The decision mechanism of the wireless communication network against interference is changed from relying on real-time coordination signaling susceptible to interference to a deterministic autonomous synchronization mode relying on shared keys between nodes and a public time reference. When the working channel communication is interrupted, the central node and the mobile node in the network do not need to send or listen to any switching instruction, and according to the calculation of the public time reference by each node, they autonomously synchronize to switch to the next channel in the channel hopping sequence to resume communication at the predetermined time slot boundary, thereby eliminating the risk of network logical splitting or losing lock caused by invalid coordination signaling from a network management logic point of view.

[0021] 2、By introducing a unified time slot cycle parameter, the longest interruption time of the network after encountering interference is limited to the remaining length of the time slot cycle. This design changes the network recovery time from an unpredictable random value dependent on signaling retries to a mechanism with a deterministic upper bound preset by system parameters, providing a predictable network service quality guarantee basis for wireless communication network applications such as avionics and other critical systems with high reliability and low latency requirements; provides a network accessibility management mechanism that uses the public time reference of the main scheme to define a fixed anchor cycle on a longer time scale; when the anchor cycle arrives, the center node suspends the execution of the secret channel hopping sequence and instead resides in the preset public anchor channel. This time domain isolation design allows the secret hopping network and the public access network to coexist under the same set of time references. New nodes do not need to know the secret sequence and can access the network deterministically based on the public time and channel parameters, resolving the contradiction between high-security networks and open node access.

[0022] 3、When the mobile node loses the external public time reference, a clock self-healing mechanism is provided. The periodic channel switching of the center node of the main scheme is used as an observable new clock calibration beacon. The node that loses the clock identifies the network time slot boundary by monitoring the exact time when the center node signal disappears, resets the local clock origin, and restores the relative synchronization with the network. The external dependency failure risk of the system operation is hedged through the reuse of the system's own operating characteristics, enabling the network to have the ability to degrade and logically self-heal when the key clock source fails. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 The figure is a schematic diagram of the autonomous synchronization channel switching process of the avionics system of the present application.

[0024] Fig. 2 The figure is a comparison chart of packet loss rates under different interference levels for the time slot cycle strategy of the present application.

[0025] Fig. 3 The figure is a node normal operation and clock failure self-healing flowchart of the present application. DETAILED DESCRIPTION

[0026] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments; based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0027] The application provides a wireless communication anti-interference method of an avionics system, which is applied to a wireless communication network comprising a center node and at least one mobile node; all nodes in the network, including the center node and the at least one mobile node, share a key in advance, can obtain a common time reference, and can switch on a preset channel sequence autonomously and synchronously under the premise of not depending on real-time coordination signaling through a pre-agreed logic, so as to avoid interference; the method also provides a clock self-recovery mechanism, when the common time reference is invalid, the nodes restore synchronization by monitoring the communication behavior in the network; during the network initialization or the node network entry stage, the center node and the at least one mobile node independently generate a channel hopping sequence with the same content based on the shared key; specifically, the shared key can be used as a seed and input into a preset pseudo-random algorithm known by all nodes in the network, so as to ensure that the sequences generated by all legal nodes in the network have the same content, and non-authorized equipment outside the network cannot predict the sequence due to the lack of the key; the channel hopping sequence can be a list comprising a plurality of channel indexes and having a deterministic order; the center node and the at least one mobile node both obtain the common time reference and share a time slot period parameter; in a typical application of the avionics system, the common time reference can be derived from a timestamp of a satellite positioning system, and the time slot period parameter is represented by T, which defines the standard residence duration of the network on each channel in the sequence and is uniformly issued by the center node when the nodes enter the network for the first time and shared by the whole network.

[0028] During the stable operation of the network, the center node and the at least one mobile node both independently and periodically perform the following first logic: the nodes continuously obtain the current time value of the common time reference , obtain the current time slot index through a deterministic calculation procedure according to the shared time slot period parameter and the sequence length of the pre-known channel hopping sequence ; the calculation procedure is as follows: wherein and have the same time unit, is a floor operation, and is a modulo operation; after the current time slot index ​The corresponding current working channel is used to autonomously switch each node's communication channel to the current working channel. Since all nodes use the same key, algorithm, time base, and time slot parameters, this calculation process does not require any real-time signaling coordination, ensuring that all nodes in the network switch to the same channel in the sequence at the same time slot boundary. To address the risk of the common time base failing in the complex electromagnetic environment of avionics, the method also includes: the mobile node continuously monitors the signal quality of the common time base; when the mobile node detects that the signal quality is lower than a preset failure threshold, the mobile node initiates a clock resynchronization mode; in the clock resynchronization mode, the mobile node executes the following second logic: the mobile node stops executing the first logic; the mobile node sets its receiver to scanning mode, polls the known channels in the channel switching sequence one by one, and re-acquires the signal of the central node; when the mobile node acquires the signal of the central node on a certain channel in the sequence, it continuously resides on that channel and continuously listens until the signal of the central node disappears; the mobile node identifies the moment when the signal disappears as the moment when the channel switching occurs; the moment of occurrence is immediately marked as the starting reference point of the new time slot period of its local clock; based on the newly marked starting reference point and the known time slot period parameters... Resume execution of the first logic.

[0029] To address the access issue for newly joined nodes, this method may further include: pre-defining a fixed anchoring channel and an anchoring time interval, with the period of the anchoring time interval being greater than the time slot period parameter; when the anchoring time interval arrives, the central node suspends the execution of the first logic based on the channel transition sequence, autonomously switches to the fixed anchoring channel, and resides for the time slot period; newly joined mobile nodes need to know the fixed anchoring channel and anchoring time interval in advance, and after obtaining a common time reference, wait on the fixed anchoring channel and receive the beacon frame from the central node when the anchoring time interval arrives, initiate an association process, and after successful association, obtain the shared key and time slot period parameter, and join the network's synchronous transition; to enable the network's anti-interference behavior to adapt to changes in the electromagnetic environment, the method may further include: the central node determines the interference level by monitoring the packet loss rate or signal-to-noise ratio in the wireless communication network; when the interference level is higher than a preset first threshold, the central node broadcasts a command to shorten the time slot period parameter. The duration of the interference; when the interference level is lower than a preset second threshold, the central node broadcasts a command to extend the duration of the time slot period parameter; in a further embodiment, to counteract the prediction of network transition rhythm by advanced interference sources, the time slot period parameter is not a fixed value, but a time slot period sequence; the central node and at least one mobile node, while generating the channel transition sequence based on the shared key, additionally and independently generate a time slot period sequence corresponding to the sequence number of the channel transition sequence; in the first logic, the original fixed and The modular arithmetic step is replaced by a stateful iterative accumulation process. Nodes determine the current common time slot index by accumulating the time slot periods in the time slot period sequence one by one by comparing with the common time base.

[0030] Example 1: This example demonstrates a specific application of the method in an avionics communication scenario. The wireless communication network employing this invention includes a central node deployed in the airport tower and mobile nodes located on the aircraft during the approach phase. Based on the aforementioned specific implementation method, the network pre-shares a key, a pseudo-random algorithm, and a channel transition sequence. Time slot period parameters The unified access satellite positioning system serves as a common time reference. The network was originally operating stably at the time calculated by the first logic. In each time slot, all network nodes work synchronously within the channel transition sequence. The corresponding current working channel A; in the time slot Before the event was over, a sudden external strong interference source appeared and completely suppressed channel A, causing an instantaneous interruption of communication between the central node and the mobile node.

[0031] When channel A is suppressed, neither the central node nor the mobile node relies on any signaling interaction and both independently execute the aforementioned first logic; each node processor continuously acquires a common time reference. Independent calculation When the public time base Crossing the first The boundary of the first time slot enters the second time slot. In each time slot, the computational procedures of all nodes in the entire network are affected by... The new current time slot index is calculated independently and synchronously as it changes. Then determine from the channel transition sequence with the same content stored locally. The corresponding current working channel B is autonomously switched to channel B; channel B is unaffected, and the central node and mobile node immediately restore communication links on the new channel; this process achieves interference avoidance without any real-time signaling coordination, and the longest network outage time is reduced. The remaining time limit; the sequence consistency guaranteed by shared keys and algorithms, and the timing consistency guaranteed by common time base and time slot parameters, transform the anti-interference mechanism from relying on fragile coordination signaling to relying on deterministic autonomous synchronous computation.

[0032] Example 2: This example quantitatively verifies the clock resynchronization mode in the method of this invention under simulated avionics conditions, verifying the ability of a mobile node to restore synchronization by utilizing the hopping behavior of the central node after losing the common time reference. The test platform is built in a hardware-in-the-loop simulation environment, including a central node simulator, a mobile node simulator, and a broadband radio frequency channel simulator. Both the central node and the mobile node load the method logic defined in the aforementioned specific implementation and share a key. Test network parameters are set as follows: channel hopping sequence. Includes 40 preset channels, time slot period parameters The time reference is set to 100ms; the common time reference is provided by an external high-precision satellite positioning system signal simulator; the local clock of the mobile node is simulated as a non-temperature compensated crystal oscillator with a clock drift rate of 50ppm, which starts drift accumulation after GPS signal loss; the network synchronization tolerance threshold is set to 1.5ms, and the network is considered to have lost lock when the clock deviation between the central node and the mobile node exceeds 1.5ms; the preset failure threshold is set to a GPS signal carrier-to-noise ratio of less than 35dB-Hz and the state lasting for more than 500ms; the test is set up with two groups: the control group adopts the same first logic based on the common time reference as this invention, without loading the clock resynchronization mode, and when GPS signal loss occurs... After the signal loss, the system relies solely on local clock drift for operation. The sample of this invention fully loads all the methods of the aforementioned specific implementation, including the first logic and clock resynchronization mode. At T=0 seconds, both sets of experiments are started, and the GPS signal simulator provides a normal signal with a C / N0 of 48dB-Hz. The network packet loss rate of both sets is maintained at a baseline level below 0.5%. At T=30.0 seconds, the GPS signal simulator instantaneously reduces the signal quality to 30dB-Hz to simulate a GPS signal loss event. The network packet loss rate and clock synchronization status of the two test groups are continuously monitored after T=30.0 seconds until T=120.0 seconds. The key test data records are shown in Table 1.

[0033] Table 1: Comparison of Network Status After Signal Loss

[0034]

[0035] Referring to Table 1, in the control group, after losing the GPS signal at T=30.0 seconds, the local clock began to accumulate a drift of 50 ppm; at T=60.0 seconds, the accumulated drift reached 1.5 ms, triggering the network synchronization tolerance threshold, causing the network packet loss rate to jump to 100%, resulting in network lockout; the sample of this invention lost the signal at T=30.0 seconds, and met the preset failure threshold at T=30.5 seconds, initiating the clock resynchronization mode; causing the network to be in a scanning and calibration state from T=30.5 seconds to T=32.3 seconds, with a packet loss rate of 100%; at T=32.2 seconds, the mobile node identified the occurrence time of the time slot boundary by monitoring the channel switching of the central node, and used this to calibrate the local clock; starting from T=32.3 seconds, the sample of this invention recovered to a baseline packet loss rate of 0.6% under the condition of continuous GPS signal loss, and maintained internal synchronization throughout.

[0036] Example 3: This example combines Figs. 1 to 3 This describes a method for resisting interference in wireless communication of an avionics system, such as... Fig. 1 As shown, the system involves four entities: a satellite positioning system, a central node, mobile nodes, and a wireless channel. Starting in the network initialization phase, the central node distributes a shared key and configures time slot period parameters to the mobile nodes. Both the central node and the mobile nodes generate identical channel transition sequences based on the shared key. During the normal synchronous channel switching process, the satellite positioning system provides a common time reference to both the central node and the mobile nodes. Each node calculates its current time slot index. When the time slot boundary is reached, the central node and the mobile nodes autonomously switch to the new working channel for data communication. Throughout this process, all nodes do not require real-time signaling coordination, achieving autonomous synchronous switching.

[0037] like Fig. 2 As shown, the horizontal axis represents the interference level, including low interference, medium interference, high interference, and extremely high interference, while the vertical axis represents the network packet loss rate in percentage. The legend shows that the packet loss rate for the fixed time slot period is represented by horizontal bars, while the packet loss rate for the adaptive time slot period is represented by diagonal bars. This graph shows that under all four interference levels—low, medium, high, and extremely high—the network packet loss rate of the adaptive time slot period strategy is lower than that of the fixed time slot period strategy. Fig. 3As shown, the process begins with system initialization and access, i.e., the central node and mobile nodes join the network and obtain basic parameters, with the input being the shared key / common time reference. Then, a channel transition sequence is generated, and a consistent sequence is generated using a pseudo-random algorithm. The process then enters the common time reference signal quality monitoring stage. If the signal quality is normal, the left-hand logic is executed, sequentially calculating the current time slot index. Based on the current time and time slot period parameters, and switching to the current working channel, the frequency switching is completed autonomously, ultimately restoring / maintaining communication and avoiding external interference sources. After the next cycle, the process returns to the monitoring stage. If the signal quality monitoring fails, the right-hand clock resynchronization mode is activated, the first logic is stopped, the receiver switches to scanning, and sequentially captures the central node signal, i.e., polls the channel transition sequence and resides there. Then, the time of channel switching is identified, i.e., the disappearance of the monitoring signal is used as the reference point. Then, the local clock is calibrated, i.e., the starting reference point of the time slot period is updated. Finally, the first logic is restored and the process returns to the monitoring stage.

[0038] Example 4: The channel transition sequence can be generated using a linear feedback shift register (LFSR). A 128-bit shared key is used as the initial state value of the LFSR. All nodes in the network adopt the same preset LFSR polynomial structure and start at the initial time point of the common time base. Each time the LFSR runs for one clock cycle, the output bits are mapped to the channel transition sequence. The channel index is specified in the table. To achieve adaptive adjustment of the time slot period parameter, the central node uses the following procedure to calculate the interference level: The central node maintains a 1-second sliding time window on the processor and continuously calculates the network packet loss rate (PLR) within the window. The interference level is determined as the weighted moving average of the PLR ​​within the sliding window. The determination of the preset first threshold is completed through an offline calibration procedure. In a laboratory environment, an interference signal with known increasing strength is injected into the network, and the network packet loss rate and the avionics data link service quality (QoS) index are monitored simultaneously. When the QoS index drops to the preset minimum acceptable level, the corresponding sliding window PLR average value is calibrated as the preset first threshold. In the clock resynchronization mode, the specific logic for the mobile node to identify and determine the channel handover time is as follows: When the mobile node is camped on a channel that has captured the signal of the central node, it samples the received signal strength indication (RSSI) of that channel at a high frequency. The node presets a signal disappearance threshold. The signal disappearance time is identified by the receiver front-end using a sliding window energy detection method, with a sampling frequency of... The calibration procedure is as follows: Determine the maximum allowable synchronization error tolerance of the system. like ms; sets the number of consecutive sampling points below the threshold required to determine the confidence level. For example, point 3; according to the formula Determine the minimum sampling frequency, where The engineering margin coefficient ranges from 0.1 to 0.5, based on... ms , set up for kHz is the sampling interval Processor maintenance length Sliding window, when the received signal strength indicator RSSI moving average is within the window continuous This is below the preset noise floor threshold. like When the signal loss threshold is reached, the processor triggers a signal loss interrupt and sets the local receiver to detect a noise floor plus a fixed margin, such as -85dBm; the mobile node continuously compares the RSSI sample value with the signal loss threshold.

[0039] When a mobile node detects that the RSSI value of three consecutive sampling points is lower than the signal disappearance threshold, the timestamp corresponding to the first sampling point that is lower than the threshold is marked as the occurrence time and the starting reference point of the new time slot period. The clock resynchronization mode includes a handover verification procedure, which is executed by the processor as follows: Step 1, the mobile node monitors the disappearance of the current channel A signal and marks the candidate handover time. Then, according to the channel hopping sequence, the mobile node switches to the next logical channel, Channel B; in step two, the mobile node initiates the verification time window on Channel B. , Duration is expressed by formula The calculation determines that, among which The preset minimum number of preamble detections is set to a value between 2 and 5. For standard frame length, The maximum allowable clock drift; Step 3, if the processor is in During this period, ChannelB demodulates the valid preamble sequence of the central node and determines... Update the local clock reference to the effective time slot boundary; Step 4, if the processor is in At the end, Channel B did not detect a legitimate signal, and it was determined that the disappearance of the Channel A signal was caused by interference suppression. The processor discarded the signal. Keep the local clock running freely and control the receiver to perform a full-band scanning procedure to re-search for the center node signal.

[0040] Example 5: This example illustrates the generation and indexing procedure when the network uses a time-slot periodic sequence to combat timing prediction interference: During the initialization phase, the central node and mobile nodes independently generate two sequences based on a shared key and a preset pseudo-random algorithm: a channel hopping sequence. and time slot periodic sequence ; Is with The corresponding serial number includes An array of duration entries, where the value of each duration entry is pseudo-randomly distributed between a preset minimum dwell time of 80ms and a maximum dwell time of 150ms. In the physical layer communication protocol, the central node transmits a wireless data frame containing a synchronization information field (SIF). The SIF is located at a fixed offset position in the PLCP header of the physical layer aggregation process, and its length is set to... For example, 8 bits carry the current public time slot index value. When the mobile node captures the central node's signal during the clock resynchronization mode scan phase, the physical layer processor demodulates the SIF field to obtain... processor with To address the key value, retrieve the local storage time slot period sequence. Search for the current dwell time From channel transition sequence Retrieve the next-hop target channel index and utilize Calculate the remaining time of the current time slot, at the moment the detection signal disappears and... Channel switching is performed when the theoretical boundary conditions are met.

[0041] use At that time, the calculation procedure used to determine the current time slot index in the first logic is adjusted to a stateful iterative accumulation method: all nodes in the network share the global cycle start time reference point. Set the network-enabled UTC zero point; obtain the current public time base. Then, the node processor performs the following operation: initialize the current index. and cumulative time ; The following logic is executed in a loop: from local storage Get from Corresponding time slot period ; Calculate the end time of the current time slot ;like Less than Loop terminates, processor determines This is the current time slot index, from Search in As the current working channel; if Greater than or equal to Then update ,and Returns to the beginning of the loop.

[0042] Example 6: This example illustrates the procedure for a newly joined mobile node to access the network; the central node and existing mobile nodes execute the first logic, in... Synchronous transitions are defined on the channel; the network is also predefined. Other fixed anchored channels and periods are much larger than The anchoring time interval; when the central node executes the first logic, an additional anchor point judgment logic is added: the central node continuously compares its local public time base with the anchoring time interval; when the start time of the anchoring time interval is determined, the central node suspends the channel switching calculated by the first logic and instead autonomously forces its communication channel to switch to the fixed anchoring channel, and stays on the anchoring channel for a period of time. During this period, beacon frames are broadcast; After the allotted time expires, the central node resumes execution of the first logic and switches to... The corresponding next time slot channel; newly joined mobile nodes only have local knowledge of the fixed anchor channel, anchor time interval, and common time reference acquisition method; after startup, the new mobile node acquires the common time reference and sets the receiver to the fixed anchor channel when the anchor time interval arrives; during this period, the new node listens for and receives beacon frames from the central node and connects to the central node through the standard association process; after successful association, the central node sends the shared key, time slot period parameters, and channel transition sequence generation algorithm to the new mobile node through a secure link; the new node uses the acquired information to generate a message identical to that of the central node. Starting from the next time slot boundary, network synchronization transitions are added.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wireless communication anti-interference method for an avionics system, applied to a wireless communication network including a central node and at least one mobile node, characterized in that, The method includes: The central node and mobile nodes, based on a shared key, independently generate identical channel hopping sequences; obtain a common time reference and share time slot period parameters; and independently and periodically execute the following first logic: calculate the current time slot index based on the common time reference and time slot period parameters, determine the current working channel from the channel hopping sequence based on the current time slot index, and autonomously switch their respective communication channels to the current working channel. The method also includes: the mobile node continuously monitoring the signal quality of the common time reference; When the mobile node detects that the signal quality is lower than a preset failure threshold, it initiates a clock resynchronization mode. In the clock resynchronization mode, the mobile node executes the following second logic: by monitoring the channel switching that occurs at the central node on the channel transition sequence, it identifies and determines the time of occurrence of the channel switching; it marks the time of occurrence as the starting reference point of the new time slot period of the mobile node's local clock; and based on the starting reference point of the new time slot period and the time slot period parameters, it resumes the execution of the first logic. In clock resynchronization mode, the steps for the mobile node to execute the second logic include: the mobile node stops executing the first logic; the mobile node sets its receiver to scanning mode and polls the channels in the channel transition sequence one by one until it captures the signal of the central node on a certain channel; the mobile node continues to camp on that certain channel until the signal of the central node disappears, and identifies the time when the signal disappears as the occurrence time.

2. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, The method also includes: pre-defining a fixed anchoring channel and an anchoring time interval, wherein the period of the anchoring time interval is greater than the time slot period parameter; when the anchoring time interval arrives, the central node suspends the execution of the first logic and autonomously switches to the fixed anchoring channel to reside in the time slot period; newly joined mobile nodes listen to and access the central node during the anchoring time interval on the fixed anchoring channel to obtain the shared key and the time slot period parameter.

3. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, The channel transition sequence is generated using a pair of shared keys and a preset pseudo-random algorithm.

4. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, The public time reference is derived from the timestamps of the satellite positioning system.

5. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, In the first logic, the step of calculating the current time slot index specifically includes: obtaining the current time value of the common time base. ; Obtain the sequence length of the channel transition sequence Current time slot index Determined through the following calculations: ,in, The duration of the time slot period parameter. and They have the same time unit.

6. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, The method further includes: the central node determines the interference level by monitoring the packet loss rate or signal-to-noise ratio in the wireless communication network; when the interference level is higher than a preset first threshold, the central node broadcasts an instruction to shorten the duration of the time slot period parameter.

7. The wireless communication anti-interference method for an avionics system according to claim 1, characterized in that, The time slot period parameter is a time slot period sequence; the central node and at least one mobile node, while generating the channel transition sequence, independently generate a time slot period sequence corresponding to the sequence number of the channel transition sequence based on the shared key; in the first logic, the step of calculating the current time slot index is replaced by iteratively accumulating the time slot period in the time slot period sequence and comparing it with the common time reference to determine the current time slot index.

8. A wireless communication anti-interference method for an avionics system according to claim 2, characterized in that, Newly joined mobile nodes only know the fixed anchoring channel and anchoring time interval. The newly joined mobile nodes obtain a common time reference and wait on the fixed anchoring channel to receive the beacon frame from the central node when the anchoring time interval arrives, and initiate the association process.

9. A wireless communication anti-interference method for an avionics system according to claim 6, characterized in that, The method also includes: when the interference level is lower than a preset second threshold, the central node broadcasts a command to extend the duration of the time slot period parameter.

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