A network topology construction method based on information fusion

Abstract

The present invention provides a method for constructing a network topology based on information fusion, comprising the following steps: a node collects information and updates a neighbor link table through a collection module; when a node evaluation period arrives, the evaluation module calculates a broadcast mode based on the collected information; if the broadcast mode is a periodic mode, periodic broadcasting is performed; if the broadcast mode is an incremental mode, incremental broadcasting is performed; the node diffuses information according to its own broadcast mode and updates a global topology table, and when the global topology table changes, the routing table is recalculated. The present invention has the beneficial effects of adaptively switching between periodic broadcast and incremental broadcast modes using the network dynamics calculated by the evaluation module, and instantly updating link information in combination with information fusion, thereby more efficiently constructing the network topology and flexibly responding to changing network scenarios.

Description

Technical Field

[0001] The present invention belongs to the field of wireless ad hoc network communication, and in particular relates to a network topology construction method based on information fusion. Background Art

[0002] Wireless ad hoc networks (WANs) are independent of pre-defined infrastructure and can adapt to changes in the absence of a central control node. Their high dynamism, diverse structures, and flexible communications have led to their widespread application in military, disaster relief, and environmental monitoring applications. In a WAN, nodes can spontaneously connect with other nodes, and the network maintains efficient and stable communication even as nodes join, leave, or migrate. As environmental conditions and mission requirements constantly change, the network topology can dynamically adjust to accommodate the evolving network environment. However, this adaptability also brings significant network management complexity. Effectively managing and optimizing network performance is a significant challenge, particularly in large-scale, dynamic environments.

[0003] Network topology construction, a critical step in network communications, collects information about the current network structure and state, providing a basis for selecting optimal routing paths. Based on this network topology, transmission efficiency and communication quality can be improved by selecting paths with fewer hops or avoiding unstable wireless channels. Because network topology is dynamic, nodes must continuously update information about links within the network during its construction and maintenance. This includes dynamic information such as the connectivity between nodes, link bandwidth, latency, and load. Nodes primarily disseminate information through periodic broadcasts and incremental broadcasts. Periodic broadcasts are communications methods that periodically send information at specific intervals; incremental broadcasts broadcast information about changed links, rather than all information.

[0004] In relatively stable networks, periodic broadcasting of link information will disseminate redundant information multiple times, consuming significant communication resources. Incremental broadcasting, on the other hand, broadcasts new link information only when links change, reducing the spread of redundant information within the network. In networks where links frequently change, incremental broadcasting generates new link information with each link change. However, the intervening link information is already outdated, making its broadcasting less meaningful and potentially causing a significant amount of invalid information to spread within the network. Periodic broadcasting, on the other hand, broadcasts link information only when the period expires, reducing the broadcast of outdated information to a certain extent. Due to the highly dynamic nature of wireless ad hoc networks, the network topology can change at any time. Therefore, a flexible and efficient method for constructing and maintaining the network topology is required to ensure stable network operation. Summary of the Invention

[0005] In view of this, the present invention aims to propose a network topology construction method based on information fusion to solve the problem that the existing technology has redundant information and is not flexible and efficient enough.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A network topology construction method based on information fusion includes the following steps:

[0008] S1, node acquisition module Collect information;

[0009] S2, determine whether the node evaluation period has arrived, if so, the evaluation module Calculate the broadcast mode based on the collected information and restart the evaluation module timer, otherwise jump to the next step S3;

[0010] S3. If the broadcast mode is periodic mode, perform periodic broadcasting;

[0011] S4. If the broadcast mode is incremental mode, perform incremental broadcast;

[0012] S5. Determine the global topology table Is there a change? If so, use the Dijkstra algorithm to update the routing table. , otherwise, jump to the next step S6;

[0013] S6, determine whether the system is finished, if so, then end the work, otherwise jump to step S2 to continue working;

[0014] In step S2, the evaluation module Calculates broadcast patterns based on collected information, including:

[0015] S21, number of neighbor changes is the sum of the number of disconnected and newly added nodes,

[0016] S22, Evaluation Module According to the evaluation cycle Measure the dynamics of the local network in which the node is located and select the current broadcast mode based on the calculation results:

[0017] Compute nodes The average of the absolute values ​​of the speed differences with one-hop neighbors;

[0018] Set the cutoff value for distinguishing modes , ,node The evaluation module uses the number of neighbor changes and speed difference Calculate the evaluation value ;

[0019] make , The smaller the value, the lower the dynamic level. When selecting incremental broadcast, The larger the value, the greater the dynamic degree. , select Periodic Broadcast.

[0020] Furthermore, in step S1, the node collection module collects information, including:

[0021] Acquisition module Collects information about speed, link status, link quality, and the number of neighbor changes from neighbor nodes.

[0022] Furthermore, in step S21, the number of neighbors changes The expression is as follows:

[0023] ;

[0024] Where, is the number of disconnected nodes, The number of newly added nodes.

[0025] Furthermore, in step S22, the node The average of the absolute values ​​of the speed differences with one-hop neighbors is expressed as follows:

[0026] ;

[0027] Where, Gather for neighbors, is the number of neighbors, is the node speed, For nodes The average of the absolute values ​​of the velocity differences with one-hop neighbors.

[0028] Furthermore, in step S22, the evaluation value , the expression is as follows:

[0029] ;

[0030] Where, , For variable parameters, is the slope adjustment parameter, A dynamic level benchmark.

[0031] Furthermore, in step S3, periodic broadcasting includes:

[0032] S31. Calculate broadcast cycle And start the periodic broadcast timer;

[0033] S32, judging the acquisition module Whether changes in neighbor links are detected, if so, update the neighbor link information table and the topology table to be determined , otherwise, jump to the next step S33;

[0034] S33: Determine whether the link information from other nodes is more effective. If so, update the topology table to be determined. , otherwise, jump to the next step S34;

[0035] S34: Determine whether the broadcast period has arrived. If so, update the global topology table. , otherwise, jump to step S32;

[0036] S35, broadcast fusion information, dynamically adjust the broadcast cycle And restart the periodic broadcast timer;

[0037] S36. Clear the topology table to be determined .

[0038] Furthermore, in step S31 and step S35, the broadcast cycle ,include:

[0039] Broadcast cycle The expression is as follows:

[0040] ;

[0041] Where, For nodes The broadcast cycle, For nodes The minimum number of hops required for any node in the network to obtain the information. is the maximum communication distance of the nodes, The speed of light.

[0042] Furthermore, in step S4, the incremental broadcast includes:

[0043] S41, when the node does not detect any neighbor link update countdown timer reaches zero, if a neighbor link is detected If a change occurs or a valid link is received from another node, the neighbor link is restarted. Update countdown timer And start the countdown timer for collecting information ;

[0044] S42, in the countdown timer for collecting information Before reaching zero, collect valid update links and add them to the pending topology table , and when collecting information countdown timer When it reaches zero, the fused link information is broadcast;

[0045] S43, when a neighbor link is detected Update countdown timer When it reaches zero, update the neighbor link Serial number and restart the update countdown timer After the information collection and fusion are completed, the topology table to be determined is broadcasted. The fusion information in

[0046] S44. Clear the topology table to be determined .

[0047] Compared with the prior art, the network topology construction method based on information fusion described in the present invention has the following beneficial effects:

[0048] (1) Through the combination of periodic broadcast and incremental broadcast, information fusion and iterative processing, information diffusion and network topology construction can be achieved more efficiently.

[0049] (2) In order to optimize the broadcast efficiency, a period dynamic adjustment strategy is introduced in periodic broadcasting, and the broadcast period is dynamically adjusted using the network diameter and the maximum communication distance of the device.

[0050] (3) In incremental broadcasting, set a countdown timer for neighbor links to make it easier to distinguish between the two states: the link information has not changed and the link is invalid. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0052] Figure 1 This is a schematic diagram of a scenario described in an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the overall process described in an embodiment of the present invention;

[0054] Figure 3 This is a schematic diagram of a periodic broadcast mode according to an embodiment of the present invention;

[0055] Figure 4 This is a schematic diagram of the incremental broadcast mode described in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0057] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0058] like Figures 1 to 4 As shown, a network topology construction method based on information fusion includes the following steps:

[0059] S1, node acquisition module Collect information;

[0060] S2, determine whether the node evaluation period has arrived, if so, the evaluation module Calculate the broadcast mode based on the collected information and restart the evaluation module timer, otherwise jump to the next step S3;

[0061] S3. If the broadcast mode is periodic mode, perform periodic broadcasting;

[0062] S4. If the broadcast mode is incremental mode, perform incremental broadcast;

[0063] S5. Determine the global topology table Is there a change? If so, use the Dijkstra algorithm to update the routing table. , otherwise, jump to the next step S6;

[0064] S6. Determine whether the system is finished. If so, end the work. Otherwise, jump to step S2 to continue working.

[0065] The specific implementation is as follows:

[0066] like Figure 1 As shown, each node deploys a collection module to collect and manage neighbor information. and an evaluation module that measures the network dynamics and selects the corresponding broadcast mode Each node also dynamically maintains a neighbor link information table The table records the real-time link information connected to the neighbor. Receive status, address, speed and other information from neighboring nodes and use the processed information in the neighbor link information table Update and evaluation modules Evaluation, etc.; Evaluation module Using the acquisition module After processing the information, the dynamic degree measurement result is output and the mode selection of periodic broadcast and incremental broadcast is completed. The selected mode result is recorded as In addition, each node also maintains a global topology table and a topology table to be determined When receiving link information from other nodes, the received valid link information is integrated with the local information to obtain new link information and fill it into the topology table to be determined. , and then complete the broadcast of fusion information and update of global topology table according to the current mode. After the change, the Dijkstra algorithm is used to calculate the shortest path to other nodes in the network and fill the routing table .

[0067] In periodic broadcast mode, dynamically adjust the broadcast period , thereby effectively managing the transmission of information and the use of bandwidth. In addition, in the incremental broadcast mode, in order to more easily distinguish whether a link has not changed for a long time or the link has failed, the node introduces an update countdown timer for each neighbor link. , whose initial value is recorded as Each link in the network carries information about the effective duration of the link. or When other nodes receive a link information, they can know the starting value of the link's valid timer. When the link's valid countdown reaches 0, it is regarded as an invalid link and the corresponding information in the global topology table is deleted.

[0068] Figure 2 This is the overall flow chart of the present invention. Collect and manage neighbor node information, including node speed, link status, link quality, number of neighbor changes, etc. It is defined as the sum of the number of disconnected and newly added nodes. The formula is as follows:

[0069] (1);

[0070] Among them, the number of disconnected nodes , the number of newly added nodes .

[0071] When the node When no neighbor is detected, it periodically broadcasts its own information so that other nodes can find it. In the network. The neighbor set of , the number of neighbors is expressed as , and its node velocity is expressed as .when When not empty, evaluates the module By evaluation cycle Measure the dynamics of the local network in which the node is located and select its current mode based on the calculation results Is it a periodic broadcast or an incremental broadcast? The following describes the calculation model of the evaluation model.

[0072] when When using node The average of the absolute values ​​of the speed differences with one-hop neighbors Measures the relative mobility of a node and its neighbors. The formula is as follows:

[0073] (2);

[0074] Set the cutoff value for distinguishing modes ,generally . The evaluation module utilizes and Calculate the evaluation value , the formula is as follows:

[0075] (3);

[0076] in, is a variable parameter, and . , used to adjust the slope. It is a rough benchmark for the degree of dynamicity and can be dynamically adjusted according to different device perception, different network environments (urban, rural or mountainous, etc.), different network density, etc. , The smaller the value, the lower the dynamic level. When , select incremental broadcast; The larger the value, the greater the dynamic degree. , select Periodic Broadcast.

[0077] Figure 3 This is a flowchart of the periodic broadcast mode. When a node detects a change in a neighbor link, it updates the neighbor table and fills in the topology table to be determined. If the neighbor link has not changed when the broadcast period is about to expire, the serial number of the link is updated and filled in the topology table to be determined. Fill the valid link information received from other nodes before the broadcast period arrives into the topology table to be determined Perform information fusion and update the global topology table when the broadcast period arrives And broadcast the fusion information, and finally clear the topology table to be determined .node The minimum number of hops required for any node in the network to obtain the information is recorded as , the maximum communication distance of nodes is expressed as . Broadcast cycle Can be based on Adjust the size of Defined as and The speed of information transmission (the speed of light ) ratios, the formula is as follows:

[0078] (4);

[0079] in, and The ratio of represents the maximum time required to communicate with a one-hop neighbor. In the early stages of networking, nodes primarily obtain information about the network status of nodes closer to them. They assume that the number of hops required to propagate broadcast information to the farthest node in the network is relatively small. In this case, a short broadcast period allows for multiple broadcasts of link information within a certain period, minimizing the impact of packet loss on network topology development. However, as link information continues to spread, nodes gradually obtain information about networks farther from them, and the minimum hop count may increase. Increasing the broadcast period can, to a certain extent, mitigate network congestion caused by the spread of redundant information.

[0080] Figure 4 This is a flowchart of the incremental broadcast mode. When the update countdown timer of the node does not detect any neighbor link reaches 0, if the neighbor link is detected Restart the neighbor link when a change occurs or a valid link is received from another node Update countdown timer And start the countdown timer for collecting information .exist Before reaching 0, collect more valid update links and add them to the pending topology table , and when When it reaches 0, the fused link information is broadcast. of When it reaches 0, update the neighbor link Serial number and reboot After the information collection and fusion are completed, the topology table to be determined is broadcasted. The fusion information in .

[0081] Example 1 is shown in the following table:

[0082]

[0083] The beneficial effects of the present invention are as follows:

[0084] (1) Through the combination of periodic broadcast and incremental broadcast, information fusion and iterative processing, information diffusion and network topology construction can be achieved more efficiently.

[0085] (2) In order to optimize the broadcast efficiency, a period dynamic adjustment strategy is introduced in periodic broadcasting, and the broadcast period is dynamically adjusted using the network diameter and the maximum communication distance of the device.

[0086] (3) In incremental broadcasting, set a countdown timer for neighbor links to make it easier to distinguish between the two states: the link information has not changed and the link is invalid.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A network topology construction method based on information fusion, characterized by: The following steps are involved: S1, node acquisition module Collect information; S2, determine whether the node evaluation period has arrived, if so, the evaluation module Calculate the broadcast mode based on the collected information and restart the evaluation module timer, otherwise jump to the next step S3; S3. If the broadcast mode is a periodic mode, perform periodic broadcasting; S4. If the broadcast mode is incremental mode, perform incremental broadcast; S5. Determine the global topology table Is there a change? If so, use the Dijkstra algorithm to update the routing table. , otherwise, jump to the next step S6; S6, determine whether the system is finished, if so, then end the work, otherwise jump to step S2 to continue working; In step S2, the evaluation module Calculates broadcast patterns based on collected information, including: S21, number of neighbor changes is the sum of the number of disconnected and newly added nodes, S22, Evaluation Module According to the evaluation cycle Measure the dynamics of the local network in which the node is located and select the current broadcast mode based on the calculation results: Compute nodes The average of the absolute values ​​of the speed differences with one-hop neighbors; Set the cutoff value for distinguishing modes , ,node The evaluation module uses the number of neighbor changes and speed difference Calculate the evaluation value ; make , The smaller the value, the lower the dynamic level. When selecting incremental broadcast, The larger the value, the greater the dynamic degree. , select Periodic Broadcast.

2. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S1, the node collection module collects information, including: Acquisition module Collects information about speed, link status, link quality, and the number of neighbor changes from neighbor nodes.

3. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S21, the number of neighbors changes The expression is as follows: ； Where, is the number of disconnected nodes, The number of newly added nodes.

4. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S22, the node The average of the absolute values ​​of the speed differences with one-hop neighbors is expressed as follows: ； Where, Gather for neighbors, is the number of neighbors, is the node speed, For nodes The average of the absolute values ​​of the velocity differences with one-hop neighbors.

5. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S22, the evaluation value , the expression is as follows: ； Where, , For variable parameters, is the slope adjustment parameter, A dynamic level benchmark.

6. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S3, periodic broadcasting includes: S31. Calculate broadcast cycle And start the periodic broadcast timer; S32, judging the acquisition module Whether changes in neighbor links are detected, if so, update the neighbor link information table and the topology table to be determined , otherwise, jump to the next step S33; S33: Determine whether the link information from other nodes is more effective. If so, update the topology table to be determined. , otherwise, jump to the next step S34; S34: Determine whether the broadcast period has arrived. If so, update the global topology table. , otherwise, jump to step S32; S35, broadcast fusion information, dynamically adjust the broadcast cycle And restart the periodic broadcast timer; S36. Clear the topology table to be determined .

7. The method for constructing a network topology based on information fusion according to claim 6, characterized in that: In step S31 and step S35, the broadcast period ,include: Broadcast cycle The expression is as follows: ； Where, For nodes The broadcast cycle, For nodes The minimum number of hops required for any node in the network to obtain the information. is the maximum communication distance of the nodes, The speed of light.

8. The method for constructing a network topology based on information fusion according to claim 1, characterized in that: In step S4, incremental broadcasting includes: S41, when the node does not detect any neighbor link update countdown timer reaches zero, if a neighbor link is detected If a change occurs or a valid link is received from another node, the neighbor link is restarted. Update countdown timer And start the countdown timer for collecting information ; S42, in the countdown timer for collecting information Before reaching zero, collect valid update links and add them to the pending topology table , and when collecting information countdown timer When it reaches zero, the fused link information is broadcast; S43, when a neighbor link is detected Update countdown timer When it reaches zero, update the neighbor link Serial number and restart the update countdown timer After the information collection and fusion are completed, the topology table to be determined is broadcasted. The fusion information in S44. Clear the topology table to be determined .

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