A wireless link self-healing method and device for linear topology

Abstract

This invention discloses a wireless link self-healing method and apparatus for linear topologies, relating to the field of wireless communication technology. The method and apparatus employ a physical frequency band isolation architecture with segmented inter-frequency main chain and globally independent backup frequencies. Through three core mechanisms—dual-dimensional disconnection judgment, distributed self-healing activating only the nodes at the two ends of the disconnection, and oscillation-free recovery from power-off snapshots—it solves the technical problems of existing chained networks, such as multi-hop performance avalanche, severe co-channel interference, network oscillations after large-scale power outages, and network-wide paralysis due to continuous failures of multiple nodes. This invention supports automatic link reconstruction in scenarios of single-node failure, continuous multi-node failure, and simultaneous disconnections at multiple locations. After the faulty node recovers, the original topology can be accurately restored based on pre-stored link snapshots, maintaining high throughput, low latency, and low interference transmission throughout.

Description

Technical Field

[0001] This invention relates to the field of wireless communication network technology, and in particular to a wireless link self-healing method and apparatus for linear topology. Background Technology

[0002] With the rapid development of IoT technology, the demand for wireless communication over long-distance strip areas is increasing. Currently, wireless chain-type cascade topologies are commonly used for data backhaul in these scenarios, but existing technologies suffer from the following insurmountable fatal flaws: Co-channel interference and multi-hop performance avalanche: Traditional co-channel half-duplex relays experience a 50% drop in throughput per hop and double the latency, becoming essentially unusable for services such as high-definition video after 7 hops. Existing Mesh self-healing technologies typically use the same frequency band as the primary service during link switching, further exacerbating co-channel interference and leading to a significant decrease in backup link throughput.

[0003] A single point of failure can paralyze the entire network: Traditional chain relays are serial structures with no backup mechanism. When a single node fails due to power outage, lightning strike, or damage, the entire link will break directly. Most existing technologies only support single-point failure recovery. When two or more consecutive nodes fail, the network will completely collapse, and it will be impossible to establish a connection across the fault zone.

[0004] Network instability after large-scale power outages: In practical field applications, large-scale synchronous power outages often occur. After existing equipment restarts, due to the lack of unified timing control and state memory, multiple nodes simultaneously initiate connection requests, which can easily lead to P-type conflicts, routing instability, and topology chaos, with recovery times lasting tens of minutes or even hours.

[0005] Self-healing is inefficient and complex to maintain: Existing Mesh self-organizing networks use a network-wide flooding method for self-healing. After a link loss, all nodes participate in routing calculations, generating a large number of broadcast storms, and the self-healing time is usually more than several minutes. Moreover, self-healing will permanently change the network topology, leading to a significant increase in long-term maintenance difficulty.

[0006] Therefore, those skilled in the art urgently need a link self-healing technology that can achieve rapid detection of disconnection, intelligent jumper reconstruction, and oscillation-free restoration of the original topology after fault recovery under a different frequency architecture, in order to overcome the many shortcomings of the existing technology. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wireless link self-healing method and device for linear topology, which realizes distributed automatic self-healing in scenarios of single node failure, multiple node continuous failure and multiple simultaneous disconnection, while maintaining high throughput, low latency and low interference transmission throughout the process, completely solving the problem of network oscillation after large-scale power outage, significantly improving the availability and reliability of the system and reducing operation and maintenance costs.

[0008] A method and apparatus for self-healing wireless links in linear topology. This invention employs a dual-frequency domain architecture of "main link segment-by-segment frequency distribution + globally independent backup frequency." The main link uses a strict segment-by-segment frequency distribution, meaning that any two adjacent main link segments use different frequencies, completely eliminating co-channel self-interference. The backup link uses a globally unified independent frequency band, completely isolated from all main link frequency bands in the physical spectrum, ensuring that the main and backup links do not interfere with each other. This architecture not only solves the multi-hop performance degradation problem but also provides a foundation for fast hops across any number of nodes.

[0009] This invention leverages the inherent characteristics of linear topology to propose a distributed self-healing mechanism that activates only the nodes at the two ends of a broken link. When a link breaks, only the nodes before and after the broken segment enter backup control mode, while all other normal nodes maintain their original main link frequency-dependent operating mode and do not send any backup broadcast frames. This mechanism completely avoids network-wide flooding, significantly improves self-healing speed, and reduces system overhead.

[0010] In this invention, when a node detects a main power failure, it utilizes the residual power of the power management module to quickly write the current link status, including radio frequency parameters, neighbor node IDs, link IDs, and topology identifiers, into a non-volatile memory. After the faulty node is powered on again, it directly reads the pre-stored link snapshot information, accurately restoring the working state before the power failure. This avoids problems such as IP conflicts and routing oscillations, achieving oscillation-free and rapid recovery.

[0011] Based on the above three core mechanisms, the complete technical solution of this invention is as follows: A wireless link self-healing method for linear topology, applied to a linear topology network consisting of multiple nodes connected in series, the method comprising the following steps: S1 system initialization: In response to node power-on, the first radio frequency module loads the pre-configured first frequency band parameters and establishes a segmented inter-frequency communication main link with adjacent nodes. The frequencies of any two adjacent main link segments do not overlap. S2 link status monitoring: Each node periodically sends heartbeat frames to its uplink and downlink neighbors, and collects physical layer signal strength indication (RSSI) and heartbeat packet status in real time. The control unit maintains and refreshes the neighbor node status table. S3 dual-dimensional disconnection decision: It adopts a joint decision mechanism of heartbeat timeout + signal strength threshold. When the number of consecutively lost heartbeat packets exceeds the threshold and RSSI is continuously lower than the preset failure threshold, it is determined that the corresponding link has been interrupted. S4 Distributed Backup Activation: After a disconnection occurs, only the two valid nodes at both ends of the disconnected segment enter the backup control state, while the remaining normal nodes maintain their original main link frequency-dependent working mode and do not generate network-wide flooding broadcasts. S5 Inter-frequency Backup Jump: The nodes at both ends of the disconnection automatically switch to the second radio frequency module, load the pre-configured second frequency band parameters, search for reachable nodes according to the preset scanning priority, establish a backup link across the faulty nodes, and restore the network connectivity; the second frequency band is completely isolated from all first frequency bands in the physical spectrum; S6 Snapshot-based Original Link Recovery: When a faulty node is powered on again, it reads the link snapshot information pre-stored in the non-volatile memory, and performs inter-frequency negotiation with neighboring nodes based on the snapshot information to automatically restore the original serial topology.

[0012] In step S3, the dual-dimensional disconnection decision specifically includes: Count the number of consecutively lost heartbeat packets N miss ; Calculate the chain break detection time T det It satisfies the formula: T det =T hello ×N miss +G rand Among them, T hello For the heartbeat cycle, G rand This is a random jitter factor used to avoid conflicts caused by multiple nodes initiating scans simultaneously; When the physical layer RSSI is lower than the preset failure threshold and the duration exceeds T det When this occurs, it is determined that the link is interrupted.

[0013] In step S5, the preset scanning priorities, from high to low, are as follows: The original chain corresponding node of S51 across the disconnected section; S52 is the legal node with the best signal strength in the same link direction; Other nodes within the S53 backup band that match the preset connection ID and encryption parameters; For all successfully matched nodes, calculate the connection score using the following formula, and select the node with the highest score to establish a backup link: Score = RSSI × 0.7 + (1 / number of hops) × 0.3.

[0014] Step S5 also includes a cyclical keep-alive mechanism: If a backup link is not established within the maximum scan window of the second RF module, the system will automatically switch back to the first RF module to continue attempting to connect to the original link, and will cyclically probe in the order of "main link scan → backup link scan" until a connection is successfully established.

[0015] In step S6, the snapshot-style original chain recovery specifically involves: When the power management module detects a power failure in the main power supply, it uses the remaining power to write the current link snapshot information into a non-volatile memory. The link snapshot information includes the radio frequency parameters before the power failure, the neighbor node ID, the link ID, and the topology identifier. After the faulty node is powered back on, a recovery request is broadcast on the original main chain frequency based on the link snapshot information; Adjacent nodes compare the signal-to-noise ratio (SINR) of the current backup link with that of the original link. If the original link has a better SINR and continues for a preset duration during periods of low traffic, a link switchback is triggered. A seamless switching strategy is adopted, which involves first establishing the original chain and then dismantling the backup.

[0016] Accordingly, the present invention also provides a wireless link self-healing device for linear topology that implements the above method, each node device comprising: The first radio frequency module is configured to establish a segmented inter-frequency communication main link with adjacent nodes based on the first frequency band. The second radio frequency module is configured to establish a backup communication link based on the second frequency band, wherein the first frequency band and the second frequency band are physically isolated from each other. Non-volatile memory, configured to store link snapshot information, primary link configuration parameters, backup configuration parameters, and neighbor node status tables; The power management module is configured to detect the main power supply status and trigger a link snapshot write operation the instant power failure. The control chip is coupled to the first RF module, the second RF module, the non-volatile memory, and the power management module, respectively, and is configured to perform link status monitoring, disconnection decision, handover decision, and routing management.

[0017] Compared with the prior art, the present invention has the following outstanding substantive features and significant progress: 1) Stable multi-hop performance and high bandwidth utilization This invention employs a segment-by-segment frequency-differentiated design on the main chain, completely eliminating co-channel self-interference. Experimental data shows that the system of this invention can still maintain over 90% of the initial throughput after 10 hops, with latency increasing by only about 10%, far superior to traditional co-channel relays and mesh self-organizing networks. This enables the invention to carry various broadband services such as high-definition video, voice, and industrial control data, meeting the requirements of industrial-grade communication.

[0018] 2) Fast self-healing speed and low system overhead This invention employs a distributed self-healing mechanism that activates only the nodes at both ends of a broken connection, eliminating broadcast storms and network-wide routing calculations. Experimental data shows that the self-healing time for this invention is only 10-30 seconds, 5-10 times faster than existing Mesh technologies. Simultaneously, system overhead is reduced by over 90%, without affecting normal business operations.

[0019] 3) Extremely survivable and adaptable to extreme environments This invention supports distributed self-healing in the face of any number of consecutive node failures and simultaneous disconnections at multiple locations. Even in extreme scenarios where a large-scale power outage causes multiple consecutive node failures, the system can automatically establish backup links across fault zones, maintaining basic network connectivity. System availability is increased from 95% in existing technologies to over 99.9%, meeting the high-reliability communication requirements of critical infrastructure.

[0020] 4) Restores oscillation-free operation and maintains long-term topological stability. The power outage snapshot oscillation-free recovery mechanism of this invention enables nodes to accurately restore to their pre-power-out working state after power restoration, without IP conflicts, MAC address conflicts, or routing oscillations. After fault recovery, the system automatically switches back to the original inter-frequency serial topology without leaving any topology distortion, ensuring the stability and maintainability of the network in the long term.

[0021] 5) Extremely low false trigger rate, stable and reliable system. This invention employs a two-dimensional disconnection decision mechanism combining heartbeat timeout and signal strength threshold, effectively distinguishing between genuine node failures and instantaneous signal fluctuations. Experimental data shows that the false trigger rate of this invention is less than 0.1%, significantly improving the stability and reliability of the system.

[0022] 6) Simple deployment and low operation and maintenance costs This invention employs a distributed, decentralized architecture, eliminating the need for a core controller and allowing for immediate use. The system features automatic fault detection, self-healing, and recovery capabilities, requiring no on-site human intervention. Furthermore, the system's topology remains stable over the long term, necessitating only periodic equipment inspections by maintenance personnel, significantly reducing field deployment and maintenance costs. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the wireless link self-healing method device for linear topology according to the present invention; Figure 2 This is a schematic diagram of the wireless link self-healing method for linear topology according to the present invention; Figure 3 This is a schematic diagram illustrating the recovery of operation after node C of the present invention fails. Detailed Implementation

[0025] 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.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1: Hardware Architecture of Wireless Link Self-Healing Device like Figure 1 As shown, each node of the wireless link self-healing device of the present invention adopts a modular design, including the following core modules: Optionally, this embodiment uses the NXP i.MX6ULL processor as the main control chip. This processor is based on the ARM Cortex-A7 core, has a clock speed of 800MHz, and features rich peripheral interfaces, including Ethernet, UART, SPI, and I2C interfaces, capable of meeting the needs of complex tasks such as wireless communication protocol processing, link status monitoring, and handover decisions. The control chip runs an embedded Linux operating system, exhibiting good stability and scalability.

[0028] Optionally, the first radio frequency module uses Qualcomm's QCA9880 chip, operating in the 5GHz band, supporting the IEEE 802.11ac standard, and achieving a maximum transmission rate of 1.3Gbps. This module connects to an 18dBi high-gain directional antenna, enabling point-to-point wireless transmission over a distance of more than 5 kilometers. The first radio frequency module is primarily used to establish the main link for segment-by-segment inter-frequency communication, responsible for the transmission of daily business data.

[0029] Optionally, the second RF module uses Qualcomm's QCA9531 chip, operating in the 2.4GHz band, supporting the IEEE 802.11n standard, and achieving a maximum transmission rate of 300Mbps. This module connects to a 12dBi high-gain directional antenna, enabling point-to-point wireless transmission over a distance of more than 10 kilometers. The second RF module is primarily used to establish a backup communication link, handling data transmission in the event of a primary link failure.

[0030] It is important to note that the 5GHz and 2.4GHz bands are completely isolated in terms of physical spectrum, with no frequency overlap. This design ensures that there is no mutual interference between the primary and backup links, and that normal communication on the primary link will not be affected even when the backup link is operational.

[0031] Optionally, this embodiment uses 16MB of SPI Flash as non-volatile memory. The Flash memory is divided into three partitions: a system partition for storing the operating system and applications; a configuration partition for storing main link configuration parameters, backup configuration parameters, neighbor node status tables, etc.; and a snapshot partition specifically for storing link snapshot information. The snapshot partition uses a cyclic writing method, which ensures that data is written quickly during power failure while avoiding wear and tear on the Flash memory.

[0032] Optionally, the power management module uses TI's TPS65217 chip, supporting a wide input voltage range of 9V to 36V, adaptable to various industrial power supply environments. The power management module incorporates overvoltage, overcurrent, and short-circuit protection circuits, effectively protecting the equipment from power failures. Most importantly, the power management module includes a large-capacity 1000μF electrolytic capacitor, capable of maintaining system operation for at least 10 seconds after a mains power failure, ensuring that link snapshot information is completely written to non-volatile memory.

[0033] In this embodiment, the power management module monitors the main power supply voltage in real time. When the main power supply voltage is normal, the large-capacity capacitor is charging. When the main power supply voltage is detected to be lower than a preset threshold, the power management module immediately sends a high-level power-down interrupt signal to the control chip. Upon receiving the interrupt signal, the control chip immediately stops all non-critical tasks and packages the current link status information, including radio frequency parameters, neighbor node IDs, link IDs, topology identifiers, etc., into the snapshot partition of the Flash memory. After writing is complete, the control chip sends an acknowledgment signal to the power management module, and the power management module cuts off the system power.

[0034] More specifically, this invention also provides a rich set of external interfaces, including two 10 / 100Mbps Ethernet interfaces, one RS232 interface, one RS485 interface, and one USB interface. These interfaces can connect to various field devices such as cameras, sensors, and PLCs to meet the needs of different application scenarios.

[0035] More specifically, this invention uses an aluminum alloy die-cast shell with an IP65 protection rating, providing dustproof, waterproof, and corrosion-resistant protection. The shell surface is designed with large heat sinks, ensuring stable operation of the equipment in a wide temperature range of -40℃ to +85℃.

[0036] Example 2: Overall Flowchart of Wireless Link Self-Healing Method like Figure 2 As shown, the overall flow of the wireless link self-healing method for linear topology of the present invention is as follows: After the node powers on, the control chip first performs hardware initialization, including clock configuration, peripheral initialization, and RF module initialization. Then, the control chip reads the main link configuration parameters from the configuration partition of the Flash memory, including operating frequency, transmit power, channel bandwidth, and encryption method. Next, the first RF module starts up and begins scanning for signals from neighboring nodes. Upon detecting a neighboring node's signal, authentication and key negotiation are performed to establish a segment-by-segment inter-frequency communication main link.

[0037] After the main link is successfully established, each node enters normal operating mode and begins transmitting service data. Simultaneously, each node periodically sends heartbeat frames to its uplink and downlink neighbors, approximately every 100ms. The heartbeat frames are encapsulated using the UDP protocol and contain information such as the node's unique ID, link ID, current RF parameters, signal strength, and link status. The control chip receives heartbeat frames from neighboring nodes in real time, collects parameters such as the physical layer signal strength index (RSSI), signal-to-noise ratio (SNR), and packet loss rate, and updates the neighbor node status table. The neighbor node status table is refreshed every 100ms, recording information such as the last heartbeat time, average RSSI value, and link status of each neighboring node.

[0038] Dual-dimensional disconnection judgment The control chip employs a dual-dimensional disconnection decision mechanism that combines heartbeat timeout and signal strength threshold to assess the link status.

[0039] The specific steps are as follows: (1) Count the number of consecutively lost heartbeat packets N miss ; (2) Calculate the chain break detection time T det The formula is: T det =T hello ×N miss +G rand T hello The heartbeat cycle is 100ms in this embodiment; G rand This is a random jitter factor, ranging from 0 to 1 second; it is used to avoid collisions caused by multiple nodes initiating scans simultaneously. (3) Calculate the average RSSI value for the most recent N sampling periods; (4) If the average RSSI value is lower than the preset failure threshold (-90dBm in this embodiment), and the time difference between the current time and the last received heartbeat exceeds T... det If so, it is determined that the corresponding link has been interrupted; (5) If only one of the above conditions is met, it is determined to be a momentary fluctuation of the signal, and the disconnection action is not triggered. The link status is monitored.

[0040] The dual-dimensional decision mechanism of this invention can effectively distinguish between real node faults and instantaneous signal fluctuations, significantly reducing the false trigger rate.

[0041] For example, when a vehicle passes by and blocks the wireless signal, the RSSI value may temporarily fall below the threshold, but the heartbeat packet is not completely lost. In this case, the system will not mistakenly judge it as a disconnection. Only when the node actually fails, neither receiving heartbeat packets nor having a signal strength that is consistently below the threshold, will the system determine it as a disconnection.

[0042] like Figure 3 As shown: When a link is determined to be broken, nodes are automatically marked as either the front or back end of the broken link based on their position in the chain topology and the direction of the break. For example, in the topology A—B—C—D—E—F, if the link between B and C is broken, B is marked as the front end of the broken link and C is marked as the back end of the broken link.

[0043] Only the front-end and back-end nodes of a broken link will enter standby control mode, while all other normal nodes will maintain their original main link frequency-dependent operation mode and will not send any standby broadcast frames. This design completely avoids network-wide flooding, significantly improves self-healing speed, and reduces system overhead.

[0044] Inter-frequency backup jumper After the two nodes at both ends of the disconnection enter the backup control state, perform the following steps to establish a backup link: (1) The control chip controls the first radio frequency module to enter a sleep state and activates the second radio frequency module; (2) Load the pre-configured backup frequency band parameters, including operating frequency, transmit power, channel bandwidth, connection ID, encryption method, etc.; (3) Search for reachable nodes according to the preset scanning priority: ① Prioritize searching nodes in the original chain that cross the disconnected segment. For example, if B and C are disconnected, then B should be searched first for C, and C should be searched first for B; ② Next, search for the legal node with the best signal strength in the same link direction; ③ Finally, search for all nodes matching the preset connection ID and encryption parameters within the backup frequency band; (4) Calculate the connection score for all successfully matched nodes according to the formula Score=RSSI×0.7+(1 / number of hops)×0.3, and select the node with the highest score; (5) Perform identity authentication and key negotiation with the selected node to establish a backup link; (6) Update the routing table and switch the service data to the backup link for transmission.

[0045] If no backup link is established within the maximum scanning window of the second RF module (30 seconds in this embodiment), the system automatically switches back to the first RF module to continue attempting to connect to the original link. The system continuously probes in the order of "primary link scan → backup link scan" until a connection is successfully established. This cyclic keep-alive mechanism ensures that the system can continue to attempt to restore the link even in extremely harsh environments.

[0046] Snapshot-based original chain recovery After the faulty node is powered on again, perform the following steps to restore the original link: (1) Power-on initialization of the faulty node: read the link snapshot information from the snapshot partition of the Flash memory, including the radio frequency parameters before power failure, neighbor node ID, link ID, topology identifier, etc. (2) Activate the first radio frequency module and configure it with the operating frequency and parameters before power failure; (3) Broadcast a recovery request frame to adjacent nodes at the original main chain frequency. The recovery request frame contains information such as the node's unique ID, link ID, and snapshot version number. (4) After receiving the recovery request frame, the neighboring node verifies the legitimacy of the node identity and the link ID; (5) Neighboring nodes compare the signal-to-noise ratio (SINR) of the current backup link with that of the original link; (6) If the signal-to-noise ratio of the original link is better than that of the current backup link, and during periods of low traffic, such as 0:00 to 6:00 AM, the link is switched back for a preset duration of 5 minutes. (7) Adopt a seamless switching strategy of “first establish the original link, then disconnect the backup link”: first establish the original main link, switch the business data to the main link for transmission, and then disconnect the backup link; (8) All nodes update their routing tables and restore the initial serial topology.

[0047] This snapshot-based original chain recovery mechanism ensures that the faulty node can be accurately restored to its pre-power-out working state after power is restored, without IP conflicts or routing oscillations. At the same time, the "build the original chain first, then dismantle the backup" switching strategy minimizes business interruption time and improves system availability.

[0048] Single-node disconnection self-healing process like Figure 3 As shown, the chain topology in this embodiment is A—B—C—D—E—F, with a total of 6 nodes. The main link frequencies for each segment are: AB: 5180MHz, BC: 5200MHz, CD: 5220MHz, DE: 5240MHz, EF: 5260MHz. The global backup frequency band is 2437MHz, which is completely isolated from all main link frequency bands.

[0049] Normal working phase All nodes operate in primary link frequency-differentiated mode, and service data is transmitted via the path A→B→C→D→E→F. Each node periodically sends and receives heartbeat frames to monitor the link status in real time.

[0050] Fault occurrence stage Node C failed due to a lightning strike, causing the links between B and C, and between C and D to break simultaneously.

[0051] Disconnection judgment stage Node B continuously loses heartbeat packets from C, and its RSSI value remains below -90dBm for more than 1 second beyond the link break detection time. It is determined that the downstream link is interrupted and is marked as the front-end node of the link break.

[0052] Node D continuously loses heartbeat packets from C, and its RSSI value remains below -90dBm for longer than the link failure detection time. Therefore, it is determined that the upstream link is interrupted and is marked as a link failure backend node.

[0053] Nodes A, E, and F maintain normal operating mode and do not participate in the backup process.

[0054] Backup link establishment phase Node B and Node D simultaneously activate the second radio frequency module and switch to the backup frequency band 2437MHz.

[0055] Node B first searches for node C, but no signal is detected; then it searches for node D in the same link direction, and a signal from node D is detected, with an RSSI value of -72dBm.

[0056] Node D first searches for node C, but no signal is detected; then it searches for node B in the same link direction, and a signal from node B is detected, with an RSSI value of -70dBm.

[0057] Node B and Node D perform identity authentication and key negotiation to establish a backup link B-D.

[0058] Update the routing table so that service data is transmitted via the path A→B→D→E→F.

[0059] Fault recovery phase After node C is repaired and powered on again, the link snapshot information is read from the Flash memory: the operating frequency is 5200MHz to communicate with B and 5220MHz to communicate with D, the neighboring nodes are B and D, and the link ID is CHAIN-001.

[0060] Node C activates the first radio frequency module and configures it to frequencies of 5200MHz and 5220MHz.

[0061] Node C broadcasts a recovery request frame to B at a frequency of 5200MHz and to D at a frequency of 5220MHz.

[0062] After receiving the recovery request frame, nodes B and D verify the identity of node C and the validity of the link ID.

[0063] Node B compares the signal-to-noise ratio (SNR) of the original link BC (35dB) with the SNR of the backup link BD (28dB) and confirms that the original link is superior.

[0064] Node D compares the signal-to-noise ratio (SNR) of the original link CD (38dB) with the SNR of the backup link BD (28dB), confirming that the original link is superior.

[0065] During periods of low traffic, first establish the BC and CD links, switch the service data back to the primary link for transmission, and then disconnect the BD backup link.

[0066] All nodes update their routing tables, restoring the initial topology A—B—C—D—E—F.

[0067] Laboratory test data: After node C loses power and connection, ping resumes after approximately 19 seconds of interruption. After node C was powered on, the ping interruption lasted for about 91 seconds before the original topology was restored. Main link throughput: 100Mbps; Backup link throughput: 50Mbps; False trigger rate: 0% (1000 hours of continuous testing, no false triggers).

[0068] Example 4: Self-healing process of continuous disconnection at multiple nodes Nodes C and D both failed due to a large-scale power outage.

[0069] Fault occurrence stage When nodes C and D lose power simultaneously, the links between B and C, C and D, and D and E break at the same time.

[0070] Disconnection judgment stage Node B detected a downstream link interruption and marked it as the front-end node of the broken link.

[0071] Node E detected an upstream link interruption and marked it as a disconnected backend node.

[0072] Nodes A and F remain in normal working mode.

[0073] Backup link establishment phase Node B and Node E switch to the backup frequency band 2437MHz.

[0074] Node B first searches for nodes C and D, but no signal is detected; then it searches for node E in the same link direction and detects the signal of node E, with an RSSI value of -78dBm.

[0075] Node E first searches for nodes C and D, but no signal is detected; then it searches for node B in the same link direction and detects the signal of node B, with an RSSI value of -76dBm.

[0076] Node B and Node E establish a backup link B-E.

[0077] Update the routing table so that business data is transmitted via the path A→B→E→F.

[0078] Fault recovery phase Nodes C and D are powered on in sequence and read their respective link snapshot information from Flash.

[0079] Node C broadcasts a recovery request to B, and node D broadcasts a recovery request to E.

[0080] Nodes B and E detected a legitimate original chain signal, triggering the back-switch mechanism.

[0081] First, establish the B-C and D-E links, then establish the C-D link, and finally disconnect the B-E backup link.

[0082] Restore the initial topology A—B—C—D—E—F.

[0083] Laboratory test data: After nodes C and D lose power and connection, ping resumes approximately 25 seconds after interruption. After nodes C and D are powered on, the ping interruption lasts for about 120 seconds before the original topology is restored. Backup link throughput: 30Mbps.

[0084] Example 5: Simultaneous Disconnection and Self-Healing Process The chain topology in this embodiment is A—B—C—D—E—F—G—H, with a total of 8 nodes. When nodes B and F fail simultaneously, three independent sub-chains are formed: A—C—D—E and G—H.

[0085] Fault occurrence stage The simultaneous failure of nodes B and F causes the links between A and B, B and C, E and F, and F and G to break simultaneously.

[0086] Disconnection judgment stage Node A detected a downstream link interruption and marked it as the front-end node of the broken link. Node C detected an upstream link interruption and marked it as a disconnected backend node. Node E detected a downstream link interruption and marked it as the front-end node of the broken link. Node G detected an upstream link interruption and marked it as a disconnected backend node.

[0087] Nodes D and H remain in normal working mode.

[0088] Backup link establishment phase Nodes A and C switch to the backup frequency band and establish a backup link A-C; Nodes E and G switch to the backup frequency band and establish a backup link E-G; Update the routing table so that service data is transmitted via the path A→C→D→E→G→H.

[0089] Fault recovery phase After node B and node F recover, they broadcast recovery requests based on the link snapshot information. Each disconnected segment independently executes the back-cut mechanism to restore the initial topology A—B—C—D—E—F—G—H.

[0090] Laboratory test data: After both locations lost connection simultaneously, the ping resumed approximately 30 seconds after the interruption. After the faulty node is powered back on, the ping interruption lasts for about 150 seconds before the original topology is restored.

[0091] Comparison test with existing technologies To verify the technical advantages of this invention, it was compared with traditional co-frequency repeaters and IEEE 802.11s Mesh self-organizing networks under the same testing environment. The testing environment was an open outdoor area with a node spacing of 1 kilometer, and a total of 10 nodes were deployed to form a 10-hop chain topology.

[0092] The test results are shown in the table below:

[0093] The test results show that the present invention is significantly superior to the existing technology in terms of multi-hop performance, self-healing speed, survivability and stability, and can well meet the high reliability communication requirements of long-distance linear scenarios.

[0094] This invention is not only applicable to wireless backbone backhaul links, but can also be extended to the following scenarios: adding access point functionality to the main chain node to provide wireless access services to surrounding edge nodes such as sensors and cameras. When a main chain node fails, the edge node can automatically switch to an adjacent main chain node to ensure uninterrupted service.

[0095] This invention can be used in hybrid networks with technologies such as fiber optic communication and 4G / 5G communication. Fiber optic communication is used in areas with available fiber optic infrastructure, while the wireless chain communication of this invention is used in areas without fiber optic infrastructure. When a fiber optic cable fails, the system can automatically switch to a wireless backup link to ensure communication continuity.

[0096] The device of this invention is small in size, lightweight, and quick to deploy, and can be used as an emergency communication device. After natural disasters such as earthquakes and floods, it can quickly deploy temporary communication links to provide communication support for rescue operations.

[0097] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A self-healing method for wireless links in linear topologies, characterized in that, Applied to linear topology networks consisting of multiple nodes connected in series, the method includes the following steps: S1 system initialization: In response to node power-on, the first radio frequency module loads the pre-configured first frequency band parameters and establishes a segmented inter-frequency communication main link with adjacent nodes. The frequencies of any two adjacent main link segments do not overlap. S2 link status monitoring: Each node periodically sends heartbeat frames to uplink and downlink neighbors, collects physical layer signal strength index RSSI and heartbeat packet status in real time, and maintains and refreshes the neighbor node status table by the control unit; S3 Dual-Dimensional Disconnection Decision: It adopts a dual-dimensional disconnection decision of heartbeat timeout + signal strength threshold. When the number of consecutively lost heartbeat packets exceeds the threshold and RSSI is continuously lower than the preset failure threshold, it is determined that the corresponding link has been interrupted. S4 Distributed Backup Activation: After a disconnection occurs, only the two valid nodes at both ends of the disconnected segment enter the backup control state, while the remaining normal nodes maintain their original main link frequency-dependent working mode and do not generate network-wide flooding broadcasts. S5 Inter-frequency Backup Jump: The nodes at both ends of the disconnection automatically switch to the second radio frequency module, load the pre-configured second frequency band parameters, search for reachable nodes according to the preset scanning priority, establish a backup link across the faulty nodes, and restore the network connectivity; the second frequency band is completely isolated from all first frequency bands in the physical spectrum; S6 Snapshot-based Original Link Recovery: When a faulty node is powered on again, it reads the link snapshot information pre-stored in the non-volatile memory, and performs inter-frequency negotiation with neighboring nodes based on the snapshot information to automatically restore the original serial topology.

2. The wireless link self-healing method for linear topology according to claim 1, characterized in that, In step S3, the dual-dimensional disconnection decision specifically includes: Count the number of consecutively lost heartbeat packets N miss ; Calculate the chain break detection time T det It satisfies the formula: T det =T hello ×N miss +G rand Among them, T hello For the heartbeat cycle, G rand This is a random jitter factor used to avoid conflicts caused by multiple nodes initiating scans simultaneously; When the physical layer RSSI is lower than the preset failure threshold and the duration exceeds T det When this occurs, it is determined that the link is interrupted.

3. The wireless link self-healing method for linear topology according to claim 1, characterized in that, In step S5, the preset scanning priorities, from high to low, are as follows: The original chain corresponding node of S51 across the disconnected section; S52 is the legal node with the best signal strength in the same link direction; Other nodes within the S53 backup band that match the preset connection ID and encryption parameters; For all successfully matched nodes, calculate the connection score using the following formula, and select the node with the highest score to establish a backup link: Score = RSSI × 0.7 + (1 / number of hops) × (0.3 ~ 0.7).

4. The wireless link self-healing method for linear topology according to claim 1, characterized in that, Step S5 also includes a cyclical keep-alive mechanism: If a backup link is not established within the maximum scan window of the second RF module, the system will automatically switch back to the first RF module to continue attempting to connect to the original link, and will cycle through the detection process in the order of "main link scan → backup link scan" until a successful connection is established.

5. A self-healing method for wireless links oriented towards linear topology according to claim 1, characterized in that, In step S6, the snapshot-style original chain recovery specifically involves: When the power management module detects a power failure in the main power supply, it uses the remaining power to write the current link snapshot information into a non-volatile memory. The link snapshot information includes the radio frequency parameters before the power failure, the neighbor node ID, the link ID, and the topology identifier. After the faulty node is powered back on, a recovery request is broadcast on the original main chain frequency based on the link snapshot information; Adjacent nodes compare the signal-to-noise ratio (SINR) of the current backup link with that of the original link. If the original link has a better SINR and continues for a preset duration during periods of low traffic, a link switchback is triggered. A seamless switching strategy is adopted, which involves first establishing the original chain and then dismantling the backup.

6. A self-healing method for wireless links oriented towards linear topology according to claim 1, characterized in that, It also supports multi-node continuous fault handling: When N consecutive nodes in a chain network lose power simultaneously, the remaining surviving nodes establish long-hop backup links across N nodes through the second radio frequency module based on the pre-stored hop-separated neighbor topology information, thus maintaining the segmented connectivity of the network.

7. A self-healing method for wireless links oriented towards linear topology according to claim 1, characterized in that, It also supports handling simultaneous disconnections at multiple locations: When multiple independent disconnected segments appear in the chain network, each disconnected segment independently executes steps S1 to S6 as described in claim 1, without interfering with each other, thus achieving segmented self-healing of the entire network.

8. A wireless link self-healing device for linear topology implementing the method of any one of claims 1 to 7, characterized in that, Each node device includes: The first radio frequency module is configured to establish a segmented inter-frequency communication main link with adjacent nodes based on the first frequency band. The second radio frequency module is configured to establish a backup communication link based on the second frequency band, wherein the first frequency band and the second frequency band are physically isolated from each other. Non-volatile memory, configured to store link snapshot information, primary link configuration parameters, backup configuration parameters, and neighbor node status tables; The power management module is configured to detect the main power supply status and trigger a link snapshot write operation the instant power failure. The control chip is coupled to the first RF module, the second RF module, the non-volatile memory, and the power management module, respectively, and is configured to perform link status monitoring, disconnection decision, handover decision, and routing management.

9. A wireless link self-healing device for linear topology according to claim 8, characterized in that, The first radio frequency module and the second radio frequency module are respectively connected to a high-gain directional antenna to improve long-distance transmission capability and anti-blocking performance.

10. The wireless link self-healing device for linear topology according to claim 8, characterized in that, The power management module supports a wide voltage input of 9V to 36V and has overvoltage, overcurrent and short circuit protection functions. It can maintain system operation for ≥10 seconds after the main power supply fails.

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