A topology discovery and routing delivery method combining wireless ad hoc network and SDN

Abstract

The application discloses a kind of topology discovery and routing issuing method combined with wireless ad hoc network and SDN, belong to wireless ad hoc network management field.It includes: issuing link state request under wireless ad hoc network;After receiving the self-information and adjacent information of all node feedback, adjacent matrix of wireless ad hoc network is constructed based on adjacent information, the self-information includes node own model, transmission capacity and residual power;According to adjacent matrix and node self-information, the priority of each node is calculated;According to the priority of node, select several backbone nodes to form the backbone node set that meets minimum dominating set, according to whether there is connection between nodes and backbone node power, the default backbone node of each ordinary node is specified and announced;After receiving the information uploaded by backbone node, decision and issue routing.The application takes node endurance as a decision factor for selecting backbone node, the transmission is carried out by the interaction of backbone node, reduces the power consumption of ordinary node, realizes the efficient endurance of cluster.

Description

Technical Field

[0001] This invention belongs to the field of wireless ad hoc network management, and more specifically, relates to a topology discovery and route distribution method that combines wireless ad hoc networks and SDN. Background Technology

[0002] With the rapid development of wireless network technology, wireless communication application scenarios are becoming increasingly complex and diverse. Among them, mobile ad hoc wireless networks (VHFs) are favored for their self-organizing, self-addressing, and self-routing characteristics. VHFs have wide applications in emergency rescue, vehicle communication, and battlefield communication. Unlike the Internet, where nodes are always connected, mobile VHFs frequently experience network partitioning due to node movement or changes in environmental conditions. This can lead to a lack of reliable end-to-end links between source and target nodes, resulting in a decline in the overall performance of the VHF network or even its inability to function properly. Therefore, the reliability of data transmission is becoming increasingly urgent for VHF research, and node energy conservation is imperative.

[0003] To address these issues, researchers are attempting to apply the latest network technologies to the design of novel ad hoc networks, with ad hoc network research combining software-defined networking (SDN) and ad hoc networks being a hot topic. After acquiring global information, the SDN controller performs global scheduling of the ad hoc network nodes, ensuring efficient use of network bandwidth resources and improving network lifetime. Furthermore, it provides corresponding adjustments when the network topology changes between ad hoc network nodes.

[0004] Patent CN113055404A provides a software-defined ad hoc network node construction method, node data forwarding method, and node architecture. It introduces software-defined concepts into ad hoc network node design, utilizing meta-protocols—the basic unit defining ad hoc network functions—to construct network nodes for data forwarding and transmission. This fully decouples the hardware and software of ad hoc network nodes, reducing node energy consumption and enhancing the service capabilities of ad hoc network nodes while maintaining compatibility with traditional network nodes. The process involves parsing the application and extracting user service characteristics, representing these characteristics as a meta-protocol generalization. This generalization is described by a five-tuple, which includes: a tag field for meta-protocol identification, an interface field for data interaction between the network control plane and data plane, an adapter for providing business API interfaces to manage the dynamic protocol stack, a database for storing meta-protocol instance information, and a bidirectional link for indicating the data transmission order of the dynamic protocol stack. A dynamic protocol stack for instantiating meta-protocols is constructed based on user service requests, and the instantiated meta-protocol parameters are adjusted by adjusting the dynamic protocol stack as node resources change. However, this solution does not take into account the power consumption caused by the SDN controller managing wireless ad hoc network nodes, which may have a significant impact on the battery life of the wireless ad hoc network cluster.

[0005] The paper "Design and Implementation of a Hybrid Network Architecture Based on SDN" proposes an architecture combining software-defined networking and wireless ad hoc networks. It essentially separates the delay-tolerant module responsible for DTN forwarding from the routing management module for conventional routing. The entire architecture consists of four main parts: a controller unit (responsible for route reception, flow table setting, and data processing), a routing management module, a softswitch unit (responsible for flow table configuration and data forwarding), and a delay-tolerant module. It's important to note that each node is a distributed controller, not a centralized controller for the entire network. Each node's communication service board can have multiple external interfaces, and the softswitch supports multiple interfaces. However, this is only an architectural approach and does not provide a detailed implementation plan. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a topology discovery and route distribution method that combines wireless ad hoc networks and SDN, aiming to solve the problem of poor endurance of existing wireless ad hoc network management methods.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a topology discovery and route distribution method combining wireless ad hoc networks and SDN, the method being applied to an SDN controller, comprising:

[0008] S1. Send a link status request via broadcast in the wireless ad hoc network;

[0009] S2. After receiving the self-information and adjacency information fed back by all nodes in the wireless ad hoc network, construct the adjacency matrix of the wireless ad hoc network based on the adjacency information. The self-information includes the node device's own model, transmission capacity and remaining power.

[0010] S3. Calculate the priority of each wireless ad hoc network node based on the adjacency matrix and the node's own information;

[0011] S4. Based on the priority of the wireless ad hoc network nodes, select several backbone nodes to form a backbone node set that conforms to the minimum dominance set. Based on whether there is a connection between the nodes and the power of the backbone nodes, designate the default backbone node for each ordinary node and notify the wireless ad hoc network cluster.

[0012] S5. Upon receiving the information uploaded by the backbone node, make a decision and issue a route.

[0013] Preferably, step S3 is as follows:

[0014]

[0015] Where P1 is the current power level of the node, P0 is the device battery capacity; R1 is the degree of the node, R0 is the number of nodes in the cluster; B1 is the transmission bandwidth of the node, B0 is the maximum transmission bandwidth of all nodes; a1, a2, and a3 are weighting coefficients.

[0016] Preferably, the step of selecting several backbone nodes based on the priority of the wireless ad hoc network nodes to form a backbone node set that conforms to the minimum dominating set is as follows:

[0017] ① Select the highest priority wireless ad hoc network node to join the backbone node set;

[0018] ② Determine whether the set satisfies the condition of a minimal dominating set;

[0019] ③ If the conditions are met, the nodes in the set are designated as backbone nodes; otherwise, the wireless ad hoc network node with the highest priority outside the backbone node set is added to the backbone node set, and then proceed to ①.

[0020] Preferably, the step of specifying the default backbone node for each ordinary node based on whether there is a connection between nodes and the power level of the backbone node is as follows:

[0021] When a regular node is connected to two backbone nodes at the same time, the backbone node with the larger battery level is designated as the default backbone node; when the battery levels are the same, the backbone node with the larger data transmission capacity is designated as the default backbone node; if they are still the same, the backbone node with the closer MAC address is designated as the default backbone node.

[0022] Preferably, step S5 is as follows:

[0023] If there is a cached path, check if there are multiple paths. If so, select the route with the lowest link load for delivery; otherwise, deliver directly.

[0024] If there is no cached path, the path is calculated and sent using Dijkstra's algorithm.

[0025] Preferably, if no suitable path is found, the SMT algorithm is used to find the path that meets the business requirements and minimizes the change in node topology; a movement command is issued to the wireless ad hoc network nodes to make them move in space, thereby changing the physical location of the cluster to meet the transmission task.

[0026] Preferably, the working status of the backbone nodes is monitored in real time. If the power of a backbone node is lower than a set threshold, the backbone node is deleted from the backbone node set and a new backbone node set is constructed.

[0027] To achieve the above objectives, in a second aspect, the present invention provides a topology discovery and route distribution method combining wireless ad hoc networks and SDN. This method is applied to wireless ad hoc network nodes and includes:

[0028] After receiving the link status request, T1 confirms the connection status with other nodes through a hello message and reports its own information and adjacency information to the SDN controller. The own information includes the node device's own model, transmission capacity and remaining power.

[0029] T2. Receives the default backbone node announced by the SDN controller;

[0030] T3. To transmit data, first determine if the destination address is a neighboring node. If so, transmit directly. Otherwise, determine if it is a backbone node. If so, transmit the information to the SDN controller. Otherwise, upload the information to the default backbone node for data upload.

[0031] To achieve the above objectives, in a third aspect, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the above-described method.

[0032] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0033] This invention proposes a topology discovery and route distribution method combining wireless ad hoc networks (WLANs) and SDN (Software-Defined Networking). Utilizing software-defined networking technology within the WLAN cluster, the node's battery life is acquired by the SDN controller as a network resource and used as a factor in backbone node selection. All interactions with the SDN controller are handled by the backbone nodes, reducing power consumption for other nodes and achieving efficient cluster battery life and basic traffic scheduling. Furthermore, if a transmission cannot be completed or its completion is too costly, commands are issued to change the physical location of nodes, thereby altering the cluster's physical location to fulfill the transmission task. Additionally, the working status of backbone nodes is monitored in real time. If a backbone node's battery level falls below a set threshold, it is removed from the backbone node set, and a new backbone node set is constructed to ensure high network battery life. Attached Figure Description

[0034] Figure 1 This is a diagram of the neighbor discovery message structure provided by the present invention.

[0035] Figure 2 The flowchart for backbone node election provided by this invention.

[0036] Figure 3The flowchart for routing information distribution provided by this invention.

[0037] Figure 4 A flowchart illustrating the topology change information distribution process provided by this invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] This invention provides a topology discovery and route distribution method combining wireless ad hoc networks and SDN, comprising the following steps:

[0040] Step 1: The SDN controller obtains the link status information of each node.

[0041] The SDN controller broadcasts link status request information, which is received by all wireless ad hoc network nodes.

[0042] Step 2: After confirming the connection status with other nodes via the hello message, the wireless ad hoc network node reports its own information, such as the model of the wireless ad hoc network node device, transmission capacity, battery life, and adjacency information, to the SDN controller.

[0043] The transmission of hello messages can occur before the SDN controller issues a request, meaning that the exchange of hello messages can occur when the self-organizing network machine starts up.

[0044] The device's own information includes its model, transmission capacity, and battery life. The device neighbor information contains three elements: device identification information, device neighbor information, and device status information. The device status information may include the wireless ad hoc network node's battery level and transmission capacity. The SDN controller uses this information to establish the global topology and select the backbone node set.

[0045] like Figure 1 As shown, a neighbor discovery message mainly consists of four parts: a header, node information, neighbor information, and a checksum. The node information includes the node device's model, transmission capacity, and battery life. The SDN controller uses the wireless ad hoc network node information as one of the bases for backbone node election. The neighbor information is based on the neighbor request message sent by the device to nearby neighbors when it starts up, and includes a set of all nodes that the device can reach within one hop.

[0046] Step 3: After obtaining the adjacency information, the SDN controller will use this information to build a global topology model.

[0047] After the wireless ad hoc network nodes transmit data frames to the SDN controller, the SDN controller maintains a matrix.

[0048] Where n represents the number of wireless ad hoc network nodes, a 12 This indicates whether there is a neighbor relationship between wireless ad hoc network node 1 and wireless ad hoc network node 2, and provides the weight information for this neighbor relationship. The weight between wireless ad hoc network nodes is related to the device's power level and transmit / receive capabilities as shown in the device information.

[0049] Step 4: Select backbone nodes using a greedy algorithm.

[0050] All interactions with the SDN controller are transmitted through the backbone node. The transmission of control information through the backbone node reduces the power consumption of other wireless ad hoc network nodes.

[0051] The SDN controller can use this matrix to calculate priorities, and the connectivity between each wireless ad hoc network node is also readily apparent. The backbone node set is the set of nodes in the entire ad hoc network that meets the minimum dominance set, or a set larger than this. Through the backbone nodes, the SDN controller can control the entire ad hoc network cluster within a one-hop range. This ensures the cluster's endurance while allowing the SDN controller to effectively control the cluster.

[0052] like Figure 2 As shown, the selection process for backbone nodes is as follows:

[0053] ① The SDN controller selects the highest-priority ad hoc wireless network node to join the backbone node set. The priority of an ad hoc wireless network node is related to its connectivity with other nodes, its power consumption, and its data transmission capabilities.

[0054]

[0055] Where P1 is the current power level of the node, P0 is the device battery capacity; R1 is the degree of the node, R0 is the number of nodes in the cluster; B1 is the transmission bandwidth of the node, B0 is the maximum transmission bandwidth of all nodes; a1, a2, and a3 are weighting coefficients.

[0056] ② Determine whether the set satisfies the minimum dominating set.

[0057] ③ If the conditions are met, the nodes in the designated set are designated as backbone nodes. If the conditions are not met, the SDN controller adds the highest priority wireless ad hoc network node outside the backbone node set to the backbone node set, and then proceeds to ①.

[0058] The entire process also includes updating and judging the backbone node set to ensure the backbone node's endurance: the SDN controller judges the working status of the backbone node, and if it is due to power or other reasons, it deletes the wireless ad hoc network node from the backbone node set before executing step ②.

[0059] Backbone wireless ad hoc network nodes interact more with the SDN controller than ordinary nodes, so their power consumption is faster. When the power of a backbone node falls below a certain value (which the SDN controller determines based on the power of the wireless ad hoc network nodes in the cluster), the SDN controller will remove it from the backbone node cluster.

[0060] like Figure 3 As shown, when a wireless ad hoc network node needs to transmit data, if it's destined for a neighboring node, the transmission is done directly; otherwise, it's transmitted via a route dispatch mechanism dispatched by the SDN controller. The route request information is reported to the SDN controller via the backbone nodes. If a suitable path exists in the SDN controller, it issues the route information. If several optimal routes exist simultaneously, they can be used in a loop to achieve local load balancing. By planning routes through the SDN controller, network resources can be utilized efficiently, network congestion can be reduced, and network transmission efficiency and quality can be guaranteed.

[0061] Specifically, when there is a data transmission task, the system will perform the following operations:

[0062] First, the wireless ad hoc network node determines whether the destination address is a neighboring node. If it is, it transmits directly; otherwise, it determines whether it is a backbone node.

[0063] If yes, the information is transmitted to the SDN controller; otherwise, the information is uploaded to the backbone node, which then handles the information upload.

[0064] Backbone nodes are crucial to the entire system, and two factors can cause changes in the backbone node set: first, insufficient node endurance; second, changes in the network topology. The SDN controller has global topology information. If the current topology cannot meet the transmission requirements, the SDN controller will issue a topology change command to complete the transmission task.

[0065] like Figure 4As shown, after receiving the relevant information, the SDN controller determines whether there is a cached path. If so, it sends the route; otherwise, it calculates the path using Dijkstra's algorithm. Specifically, if multiple paths exist, the SDN controller selects the route with the lowest link load for transmission. If no suitable path exists, the SDN controller uses the SMT algorithm to find the path that meets the service requirements and minimizes node topology changes. The SDN controller then sends movement commands to the wireless ad hoc network nodes, causing them to move spatially to fulfill the transmission task.

[0066] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for topology discovery and route distribution combining wireless ad hoc networks and SDN, characterized in that, This method is applied to SDN controllers and includes: S1. Send a link status request via broadcast in the wireless ad hoc network; S2. After receiving the self-information and adjacency information fed back by all nodes in the wireless ad hoc network, construct the adjacency matrix of the wireless ad hoc network based on the adjacency information. The self-information includes the node device's own model, transmission capacity and remaining power. S3. Calculate the priority of each wireless ad hoc network node based on the adjacency matrix and the node's own information; S4. Based on the priority of the wireless ad hoc network nodes, select several backbone nodes to form a backbone node set that conforms to the minimum dominance set. Based on whether there is a connection between the nodes and the power of the backbone nodes, designate the default backbone node for each ordinary node and notify the wireless ad hoc network cluster. S5. Receive information uploaded by the backbone node, make a decision and issue a route; Based on the priority of the wireless ad hoc network nodes, several backbone nodes are selected to form a backbone node set that conforms to the minimum dominating set, as detailed below: ① Select the highest priority wireless ad hoc network node to join the backbone node set; ② Determine whether the set satisfies the condition of a minimal dominating set; ③ If the conditions are met, the nodes in the set are designated as backbone nodes; otherwise, the wireless ad hoc network node with the highest priority outside the backbone node set is added to the backbone node set, and then proceed to ①.

2. The method as described in claim 1, characterized in that, Step S3 is as follows: in, This represents the current battery level of the node. For the device's battery capacity; Let the degree of this node be denoted as . This represents the number of nodes in the cluster. This represents the transmission bandwidth of the node. This represents the maximum transmission bandwidth for all nodes. These are the weighting coefficients.

3. The method as described in claim 1, characterized in that, The default backbone node for each ordinary node is specified based on whether there is a connection between nodes and the power level of the backbone node, as follows: When a regular node is connected to two backbone nodes at the same time, the backbone node with the larger power level is designated as the default backbone node; when the power levels are the same, the backbone node with the larger data transmission capacity is designated as the default backbone node. If they are still the same, the device with the closer MAC address will be designated as the default backbone node.

4. The method as described in claim 1, characterized in that, Step S5 is as follows: If there is a cached path, check if there are multiple paths. If so, select the route with the lowest link load for delivery; otherwise, deliver directly. If there is no cached path, the path is calculated and sent using Dijkstra's algorithm.

5. The method as described in claim 4, characterized in that, If no suitable path is found, the SMT algorithm is used to find the path that meets the business requirements and minimizes the change in node topology; a movement command is issued to the wireless ad hoc network nodes to make them move in space, thereby changing the physical location of the cluster to meet the transmission task.

6. The method according to any one of claims 1 to 5, characterized in that, The working status of backbone nodes is monitored in real time. If the power of a backbone node is lower than the set threshold, the backbone node is deleted from the backbone node set and a new backbone node set is constructed.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it can implement the method of any one of claims 1 to 6.

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