A passive routing method, a hybrid routing method and a hybrid routing system

Abstract

The application belongs to the technical field of wireless communication ad hoc network, and discloses a passive routing method, a hybrid routing method and a hybrid routing system. The passive routing method comprises the following steps: acquiring geographical position information and device capability information of a node and other nodes in a network; calculating link states between nodes in the network; generating a network topology structure diagram; calculating an optimal path to form a preferred path set; triggering a source node to send a routing discovery request message when a routing loss event occurs or data packets need to be forwarded across clusters; sending a routing discovery response message by a destination node after receiving the routing discovery request message; and generating a routing table item by the source node after receiving the routing discovery response message and adding the routing table item to a passive routing table. The application avoids routing holes, eliminates routing loops, improves routing efficiency and routing reliability, reduces the occupation of wireless channel resources by routing discovery service broadcast information, and has good applicability in a UAV group scene.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication ad hoc network technology, and particularly relates to a passive routing method, a hybrid routing method, and a hybrid routing system. The passive routing method is an ad hoc network routing method that integrates geographical location information and device capability information. The hybrid routing method integrates the passive routing method and the active routing method. The hybrid routing system implements the hybrid routing method. Background Technology

[0002] In existing technologies, proactive routing strategies offer advantages such as good timeliness of first-packet data and accurate routing information, making them well-suited for small-scale networking scenarios. However, as the scale of unmanned clusters expands, the number of wireless ad hoc network nodes also increases, significantly increasing the overhead of proactive routing strategies. Excessive overhead can degrade network transmission performance and even lead to network congestion. To address this, a logical clustering approach can be used to limit the scope of routing information to a single cluster domain, thereby controlling overhead. Nodes within the same cluster domain establish routes through proactive routing strategies, and then the cluster head region connects routes between nodes in different cluster domains, thus completing the establishment of the entire network route. This clustered proactive routing strategy retains the advantages of proactive routing while limiting the scale of overhead.

[0003] However, the clustering-based proactive routing strategy also brings new problems. Due to the constraints of logical clustering, even if two nodes in different cluster domains have the conditions and physical capabilities for single-hop transmission, packet transmission still needs to be forwarded through the cluster head domain, resulting in a decrease in network bandwidth utilization efficiency. Summary of the Invention

[0004] To address the aforementioned problems in routing within large-scale self-organizing networks, this invention proposes a passive routing method that integrates geographical location information and device capability information, comprising the following steps:

[0005] Step 1: Obtain the geographical location information of this node and other nodes in the network. Nodes in the network can exchange geographical location information with other nodes based on the topology established through active routing, and form a set of geographical location information through periodic updates or location prediction. ,in, For the first in the network i The geographic location information of each node, which is used to calculate the distance between nodes, is latitude and longitude information and elevation information or projected coordinate position and elevation information;

[0006] Step 2: Obtain device capability information for this node and other nodes in the network. Nodes in the network can exchange device capability information with other nodes based on the topology established through active routing, generating a set of device capability information. ,in, For the first in the network i The device capability information of each node is used as a parameter of the channel propagation model for estimating the link state between nodes. The device capability information includes the device's transmit power, antenna gain, operating frequency, and demodulation sensitivity.

[0007] Step 3: Calculate the link status between each node in the network based on geographical location information and device capability information, forming a link status set. ,in, For nodes i and nodes j The link states between them are divided into connectionless states. N One-way connection state H and bidirectional connection status S The link state has weights M ;

[0008] Step 4: Generate network topology graph: Using this node as the source node, select all links in the bidirectional connection state as edges to generate a network topology graph, where the link weights are... M The weights of the edges in the topological graph;

[0009] Step 5: Based on the network topology diagram generated in Step 4, using this node as the source node and other nodes in the network as destination nodes, utilize... Dijkstra Algorithms or other path selection algorithms calculate the optimal path and form a set of preferred paths;

[0010] Step 6: When a route loss event occurs or data packets need to be forwarded across clusters, the source node is triggered to send a route discovery request message. The route discovery request message carries the preferred path information generated in step 5. Nodes along the route use the preferred path as the forward propagation path to propagate the route discovery request information to the destination node.

[0011] Step 7: After receiving the route discovery request message, the destination node sends a route discovery response message. The route discovery response message is propagated back to the source node along the preferred link. During the back propagation, the nodes along the way add the link quality information of themselves and their neighbors to the route discovery response message. The link quality information includes signal strength and signal-to-noise ratio.

[0012] Step 8: After receiving the route discovery response message, the source node generates a route table entry and adds the route table entry to the passive route table. The route table entry contains destination node information, next-hop node information, hop count information, and link quality information for each hop.

[0013] Furthermore, in step 3, the nodes are calculated based on geographical location information and equipment capability information. i and nodes j The link status process is as follows:

[0014] Step 3.1: From the set of geographic location information in Step 1 Get from and and calculate the nodes i and nodes j Distance between ;

[0015] Step 3.2: Calculate the node using the channel propagation model algorithm. i Send, node j Maximum communication distance during reception Conversely, recalculate the nodes. j Send, node i Maximum communication distance during reception ;

[0016] Step 3.3: Determine the connection status of the link:

[0017] when At that time, the link status is a bidirectional connection.

[0018] when At that time, the link status is a connectionless state;

[0019] when and At that time, the link status is a one-way connection.

[0020] Step 3.4: Calculate the link weights based on the nodes. i ,node j Information on their respective equipment capabilities and distances And combine the channel propagation model algorithm to calculate the node i and nodes j The minimum value among the respective received power margins is selected as the link weight.

[0021] This invention also proposes a hybrid routing system, including a clustered active route maintenance module, a passive route maintenance module, and a route fusion module, wherein,

[0022] The clustered active routing maintenance module is used to establish and maintain the active routing table. It uses the active routing method to establish intra-cluster and inter-cluster routes. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information includes signal strength and signal-to-noise ratio.

[0023] The passive routing maintenance module is used to establish and maintain the passive routing table. It uses the perceived geographical location information and device capability information to pre-establish link status information and network topology, and selects one or more preferred paths based on the pre-established network topology. Then, it uses the preferred paths to guide the propagation of passive routing discovery protocol messages to complete the establishment of the passive routing table. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information includes signal strength and signal-to-noise ratio.

[0024] The routing fusion module is used to merge the active routing table and the passive routing table. When there are paths to the destination node in both the active routing table and the passive routing table, the path with the fewest hops or the largest link weight is selected as the routing result and a forwarding routing table is generated.

[0025] This invention also proposes a hybrid routing method based on the above-mentioned hybrid routing system, comprising the following steps:

[0026] Step 1: When an active or passive route generates a route update, a route update message is sent to the route fusion module;

[0027] Step 2: After receiving the route update message, the route fusion module merges the active route table entries and the passive route table entries to obtain a set of all reachable destination nodes;

[0028] Step 3: Traverse all reachable destination nodes, check whether the destination node has a routing table entry in the active routing table and passive routing table, and decide how to add the routing table entry to the forwarding routing table according to Step 4 and Step 5;

[0029] Step 4: If an entry for reaching the destination node exists only in the active or passive routing table, then directly add the routing entry to the forwarding routing table.

[0030] Step 5: If both the active routing table and the passive routing table contain routing entries leading to the destination node, then calculate the weights of the two routing table entries respectively. Q The path with the larger weight is selected as the optimal path, and the corresponding entry is added to the forwarding routing table.

[0031] Furthermore, in step 5, the weight of the routing table entry is calculated. Q for:

[0032] ,

[0033] in, N This represents the hop count of the route. Let be the signal-to-noise ratio of the i-th hop. i =1,2,…, N .

[0034] This invention generates optimal paths while avoiding routing holes and eliminating routing loops, thus improving routing efficiency and reliability. Furthermore, because the route discovery protocol messages propagate along the optimal path using unicast, broadcast propagation is unnecessary, effectively reducing the wireless channel resource consumption of route discovery service broadcast information. This invention is well-suited for scenarios where channel propagation models are easily predictable, especially in UAV swarm scenarios. Attached Figure Description

[0035] Figure 1 This is a diagram illustrating hybrid routing optimization.

[0036] Figure 2 This is a structural diagram of the hybrid routing system of the present invention;

[0037] Figure 3 This is a basic flowchart of the passive routing method of the present invention;

[0038] Figure 4 This is a flowchart of the hybrid routing method of the present invention;

[0039] Figure 5 This is a network structure diagram of an embodiment of the present invention;

[0040] Figure 6 This is a clustered active routing topology diagram according to an embodiment of the present invention;

[0041] Figure 7 This is a pre-built network topology diagram. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] The basic process of the passive routing method of this invention, which integrates geographic location information and device capability information, is as follows: Figure 3 As shown, the steps are explained below.

[0044] Step 1: Obtain the geographical location information of this node and other nodes in the network. Nodes in the network can exchange geographical location information with other nodes based on the topology established through active routing. This can be achieved through periodic updates or location prediction to form a set of geographical location information. ,in, This represents the geographic location information of the i-th node in the network. The geographic location information is used to calculate the distance between nodes and can be latitude, longitude, and elevation, or it can be projected coordinates and elevation.

[0045] Step 2: Obtain device capability information for this node and other nodes in the network. Nodes in the network can exchange device capability information with other nodes based on the topology established through active routing. Generate a set of device capability information. ,in, This refers to the device capability information of the i-th node in the network. This device capability information, used as parameters in the channel propagation model for estimating the link state between nodes, may include, but is not limited to, information such as the device's transmit power, antenna gain, operating frequency, and demodulation sensitivity.

[0046] Step 3: Calculate the link status between each node in the network based on geographical location information and device capability information, forming a link status set. ,in, Represents a node i and nodes j The link status between them. Link status can be divided into connectionless state, one-way connection state, and two-way connection state, represented by letters respectively. N , H and S This is used to represent the link state. The link state can have weights. M A higher weight indicates a better link quality.

[0047] For example: The value is ( S ,5) represents a node i and nodes j The link between them is in a bidirectional connection state with a weight of 5.

[0048] Based on geographic location information and device capability information, computing nodes i and nodes j The link status process is as follows:

[0049] 1) Obtain from the geographic location information set and and calculate the nodes i and nodes j Distance between ;

[0050] 2) Select a suitable channel propagation model algorithm (e.g., in high-altitude line-of-sight UAV swarm wireless communication scenarios, a free-space propagation model algorithm can be selected) for computation nodes. i Send, node j Maximum communication distance during reception Conversely, recalculate the nodes.j Send, node i Maximum communication distance during reception ;

[0051] 3) Determine the connection status of the link:

[0052] when At that time, the link status is a bidirectional connection.

[0053] when At that time, the link status is a connectionless state;

[0054] when and At this time, it is in a one-way connection state;

[0055] 4) Calculate the link weight.

[0056] In one specific embodiment, it can be based on the node i ,node j Information on their respective equipment capabilities and distances And combine the selected channel propagation model algorithm to calculate the node i and nodes j The minimum value among the respective received power margins is selected as the link weight.

[0057] Step 4: Generate the network topology diagram.

[0058] Using this node as the source node, select all links in the bidirectional connection state as edges to generate a network topology graph, where the weights of the links are... M This refers to the weight of the edges in the topological graph.

[0059] Step 5: Based on the network topology diagram, using this node as the source node and other nodes in the network as destination nodes, utilize... Dijkstra Algorithms or other path selection algorithms calculate the preferred path to each destination node, forming a set of preferred paths.

[0060] Preferably, multiple preferred paths with low correlation can be selected for each destination node. Multiple preferred paths can improve the success rate of route discovery and establishment.

[0061] Step 6: When a route loss event occurs or when data packets need to be forwarded across clusters, the source node is triggered to send a route discovery request message.

[0062] The preferred path information generated in step 5 is carried in the route discovery request message, and the nodes along the route use the preferred path as the forward propagation path to propagate the route discovery request information to the destination node.

[0063] Step 7: After receiving the route discovery request message, the destination node sends a route discovery response message.

[0064] The route discovery response message propagates back to the source node along the preferred path. During this back propagation, nodes along the way add their own and their neighbors' link quality information to the route discovery response message. This link quality information may include signal strength and signal-to-noise ratio. SNR Information such as...

[0065] Step 8: After receiving the route discovery response message, the source node generates a routing table entry and adds it to the passive routing table. This routing table entry contains destination node information, next-hop node information, hop count information, and link quality information for each hop.

[0066] In this invention, nodes in the network utilize perceived geographical location information and device capability information to pre-construct link states and network topology. Based on the pre-constructed network topology, one or more preferred paths are selected. Route discovery protocol messages propagate using the preferred paths as the forward propagation paths. This invention effectively avoids route holes, route loops, and broadcasting of route discovery protocols, improving the reliability, stability, and timeliness of routing protocols while reducing network bandwidth consumption.

[0067] Based on the passive routing method of this invention, and combined with the active routing method, this invention also proposes a hybrid routing method that can take into account the advantages of both routing strategies. The basic process is as follows: Figure 4 As shown.

[0068] For proactive routing methods, a known proactive routing strategy (such as OLSR) can be selected to construct the proactive routing table entries. The generated routing table entries contain destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information may include signal strength and signal-to-noise ratio. SNR Information such as...

[0069] Step 1: When an active or passive route generates a route update, it sends a route update message to the route fusion module.

[0070] Step 2: After receiving the route update message, the route fusion module merges the active route table entries and the passive route table entries to obtain a set of all reachable destination nodes;

[0071] Step 3: Traverse all reachable destination nodes, check whether the destination node has a routing table entry in the active routing table and passive routing table, and decide how to add the routing table entry to the forwarding routing table according to Step 4 and Step 5.

[0072] Step 4: If an entry for reaching the destination node exists only in the active or passive routing table, then directly add the routing entry to the forwarding routing table.

[0073] Step 5: If both the active routing table and the passive routing table contain routing entries leading to the destination node, then calculate the weights of the two routing table entries respectively. Q The path with the larger weight is selected as the optimal path, and the corresponding entry is added to the forwarding routing table.

[0074] In a specific embodiment of the present invention, the hop count information and the signal-to-noise ratio of each hop are known. SNR Information calculation of routing table entry weights Q The formula is:

[0075] ,

[0076] in, N This represents the hop count of the route. Let be the signal-to-noise ratio of the i-th hop. i =1,2,…, N .

[0077] The hybrid routing method of this invention is based on clustered active routing. When a cross-cluster packet arrives, it can be transmitted immediately according to the multi-hop path generated by the active routing strategy, while simultaneously triggering the execution of a passive routing strategy to attempt to find a better cross-cluster transmission path. This strategy combines the advantage of active routing, where the first packet transmission does not need to wait for route discovery, with the optimization of multi-hop transmission paths between clusters through passive routing strategies. A schematic diagram of the hybrid routing optimization is shown below. Figure 1 As shown.

[0078] This invention also proposes a hybrid routing system, the architecture of which is as follows: Figure 2 As shown, it includes a clustered active route maintenance module, a passive route maintenance module, and a route fusion module.

[0079] The clustered active routing maintenance module is used for the creation and maintenance of active routing tables. It can utilize existing known active routing strategies (such as the OLSR protocol) to establish intra-cluster and inter-cluster routes. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information may include signal strength and signal-to-noise ratio. SNR Information such as...

[0080] The passive routing maintenance module, based on geographic location and device capability information, is used for the creation and maintenance of passive routing tables. This module pre-establishes link state information and network topology using the perceived geographic location and device capability information. Based on the pre-built network topology, it selects one or more preferred paths and uses these preferred paths to guide the propagation of passive route discovery protocol messages, thus completing the creation of the passive routing table. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information may include signal strength and signal-to-noise ratio. SNR Information such as... The passive routing maintenance module is used to implement the passive routing method of the present invention described above.

[0081] The route fusion module merges the active and passive routing tables. When both the active and passive routing tables contain paths to the destination node, it selects the path with fewer hops or a higher link weight as the routing result and generates a forwarding routing table. The forwarding routing table is the result of route optimization and is used for the forwarding path of the final control data packets.

[0082] Example

[0083] like Figure 5 The example network structure shown contains 8 communication device nodes. The dashed lines connecting the communication device nodes indicate that they have the physical capability to conduct wireless communication.

[0084] After implementing the clustered active routing strategy, the generated topology is as follows: Figure 6 As shown, nodes 2, 3, 4, and 5 belong to cluster domain 1; nodes 6, 7, and 8 belong to cluster domain 2; and nodes 1, 2, and 6 belong to cluster head domain.

[0085] This embodiment takes node 5 as an example. Its active routing table entry is shown in the table below. The link information of the i-th hop is represented by (ID, SNR), where ID is the ID of the i-th hop node and SNR represents the SNR value of the i-th hop. NAN indicates that the information does not exist.

[0086] Target node Next hop node Number of jumps One jump information Second-hop information Three-hop information Four-jump information 1 4 3 （4,10） （2,3） （1,6） NAN 2 4 2 （4,10） （2,3） NAN NAN 3 3 1 （3,4） NAN NAN NAN 4 4 1 （4,10） NAN NAN NAN 6 4 3 （4,10） （2,3） （6,5） NAN 7 4 4 （4,10） （2,3） （6,5） （7,2） 8 4 4 （4,10） （2,3） （6,5） （8,4）

[0087] Node 5 interacts with other nodes through the topology established by active routing to obtain their geographic location coordinates, as shown in the table below:

[0088] node Projected coordinate position information (x, y, z) 1 （2510, 6700, 0） 2 （6210, 4510, 0） 3 （9180, 3740, 0） 4 （8880, 5960, 0） 5 （10280, 6300, 0） 6 （6060, 9450, 0） 7 （9310, 8050, 0） 8 （8600, 10290, 0）

[0089] Node 5 interacts with other nodes to obtain device capability information through the topology established by active routing, as shown in the table below:

[0090] node Transmit power (dBm) Center frequency (MHz) Demodulation sensitivity (dBm) 1 15 1400 -98 2 15 1400 -98 3 10 1400 -98 4 10 1400 -98 5 10 1400 -98 6 15 1400 -98 7 10 1400 -98 8 10 1400 -98

[0091] Node 5 calculates the link status between nodes in the network based on the acquired geographical location information and device capability information. The link status calculation process is as follows:

[0092] 1) Calculate the distance between node i and node j. The calculation formula is:

[0093] ;

[0094] 2) Calculate the maximum communication distance when node i sends and node j receives. Then calculate the maximum communication distance when node j sends and node i receives. .by For example, the calculation formula is:

[0095] ;

[0096] in, Let be the transmit power of node i. Let be the receiving sensitivity of node j.

[0097] 3) Determine the connection status of the link.

[0098] when At that time, the link status is a bidirectional connection.

[0099] when At that time, the link status is a connectionless state;

[0100] when and At this time, it is in a one-way connection state;

[0101] 4) Assuming the link weight of each bidirectional link is 1, the link state information is shown in the table below:

[0102] node 2 3 4 5 6 7 8 1 (S,1) (H,1) (H,1) (H,1) (S,1) (H,1) (H,1) 2 (S,1) (S,1) (H,1) (S,1) (H,1) (H,1) 3 (S,1) (S,1) (H,1) (N,1) (N,1) 4 (S,1) (H,1) (S,1) (N,1) 5 (H,1) (S,1) (N,1) 6 (S,1) (S,1) 7 (S,1) 8

[0103] Using node 5 as the source node, and selecting all links in the bidirectional connection state as edges, the following can be generated: Figure 7 The network topology diagram is shown below.

[0104] Using node 5 as the source node, the optimal one-hop path to node 8 is calculated using Dijkstra's algorithm as {node 5, node 7, node 8}.

[0105] When a cross-cluster domain service occurs with node 5 as the source node and node 8 as the destination node, the passive routing protocol is triggered. Node 5 embeds the preferred path into the routing discovery request information and sends the routing discovery request information to node 7. After receiving the routing discovery request information, node 7 parses the preferred path in the header to obtain the next-hop node information and sends the routing discovery request information to node 8. After receiving the routing discovery request information, node 8 finds that it is the destination node and terminates the propagation of the routing discovery request information.

[0106] After receiving the route discovery request message, node 8 adds the link quality information with node 7 to its route discovery response message and sends the route discovery response message to node 7. After receiving the route discovery response message, node 7 adds the link quality information with node 5 and sends the route discovery response message to node 5.

[0107] After receiving the route discovery response message, node 5 generates a route table entry to node 8 and adds it to the passive routing table. Simultaneously, node 7, as a relay node in the route path, is also added to the passive routing table. The generated passive routing table results are shown in the table below.

[0108] Target node Next hop node Number of jumps One jump information Second-hop information Three-hop information Four-jump information 8 7 2 （7,10） （8,8） NAN NAN 7 7 1 （7,10） NAN NAN NAN

[0109] After completing the update of the passive routing table entries, node 5 sends a routing update message to the routing fusion module.

[0110] After receiving the route update message, the route fusion module of node 5 merges the active route table entries and the passive route table entries to obtain the set of reachable destination nodes {node 1, node 2, node 3, node 4, node 6, node 7, node 8}.

[0111] Iterate through all reachable destination nodes. Routing entries for nodes 1, 2, 3, 4, and 6 that only exist in the active routing table are directly added to the forwarding routing table.

[0112] The routing table entry for reaching node 8 exists in both the active and passive routing tables. (Based on the calculation method...) The weights of the active routing table entry and the passive routing table entry are calculated to be 1.24 and 4.47 respectively. The passive routing table entry has a higher weight, so the passive routing table entry is added to the forwarding routing table.

[0113] The final merged forwarding routing table results are shown in the table below.

[0114] Target node Next hop node Number of jumps One jump information Second-hop information Three-hop information Four-jump information 1 4 3 （4,10） （2,3） （1,6） NAN 2 4 2 （4,10） （2,3） NAN NAN 3 3 1 （3,4） NAN NAN NAN 4 4 1 （4,10） NAN NAN NAN 6 4 3 （4,10） （2,3） （6,5） NAN 7 7 1 （7,10） NAN NAN NAN 8 7 2 （7,10） （8,8） NAN NAN

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A passive routing method, characterized in that, The method integrates geographic location information and device capability information, and includes the following steps: Step 1: Obtain the geographical location information of this node and other nodes in the network. Nodes in the network can exchange geographical location information with other nodes based on the topology established through active routing, and form a set of geographical location information through periodic updates or location prediction. ,in, For the first in the network i The geographic location information of each node, which is used to calculate the distance between nodes, is latitude and longitude information and elevation information or projected coordinate position and elevation information; Step 2: Obtain device capability information for this node and other nodes in the network. Nodes in the network can exchange device capability information with other nodes based on the topology established through active routing, generating a set of device capability information. ,in, For the first in the network i The device capability information of each node is used as a parameter of the channel propagation model for estimating the link state between nodes. The device capability information includes the device's transmit power, antenna gain, operating frequency, and demodulation sensitivity. Step 3: Calculate the link status between each node in the network based on geographical location information and device capability information, forming a link status set. ,in, For nodes i and nodes j The link states between them are divided into connectionless states. N One-way connection state H and bidirectional connection status S The link state has weights M ; Step 4: Generate network topology graph: Using this node as the source node, select all links in the bidirectional connection state as edges to generate a network topology graph, where the link weights are... M The weights of the edges in the topological graph; Step 5: Based on the network topology diagram generated in Step 4, using this node as the source node and other nodes in the network as destination nodes, utilize... Dijkstra The algorithm calculates the optimal path and forms a set of preferred paths; Step 6: When a route loss event occurs or data packets need to be forwarded across clusters, the source node is triggered to send a route discovery request message. The route discovery request message carries the preferred path information generated in step 5. Nodes along the route use the preferred path as the forward propagation path to propagate the route discovery request information to the destination node. Step 7: After receiving the route discovery request message, the destination node sends a route discovery response message. The route discovery response message is propagated back to the source node along the preferred path. During the back propagation process, the nodes along the way add their own and their neighbor nodes' link quality information to the route discovery response message. The link quality information includes signal strength and signal-to-noise ratio. Step 8: After receiving the route discovery response message, the source node generates a route table entry and adds the route table entry to the passive route table. The route table entry contains destination node information, next-hop node information, hop count information, and link quality information for each hop.

2. The passive routing method according to claim 1, characterized in that, In step 3, the nodes are calculated based on geographical location information and equipment capability information. i and nodes j The link status process is as follows: Step 3.1: From the set of geographic location information in Step 1 Get from and and calculate the nodes i and nodes j Distance between ; Step 3.2: Calculate the node using the channel propagation model algorithm. i Send, node j Maximum communication distance during reception Conversely, recalculate the nodes. j Send, node i Maximum communication distance during reception ; Step 3.3: Determine the connection status of the link: when At that time, the link status is a bidirectional connection. when At that time, the link status is a connectionless state; when and At that time, the link status is a one-way connection. Step 3.4: Calculate the link weights based on the nodes. i ,node j Information on their respective equipment capabilities and distances And combine the channel propagation model algorithm to calculate the node i and nodes j The minimum value among the respective received power margins is selected as the link weight.

3. A hybrid routing system, characterized in that, It includes a clustered active route maintenance module, a passive route maintenance module, and a route fusion module, among which, The clustered active routing maintenance module is used to establish and maintain the active routing table. It uses the active routing method to establish intra-cluster and inter-cluster routes. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information includes signal strength and signal-to-noise ratio. The passive routing maintenance module is used for the establishment and maintenance of the passive routing table. It pre-establishes link status information and network topology using perceived geographical location information and device capability information, and selects one or more preferred paths based on the pre-established network topology. These preferred paths then guide the propagation of passive routing discovery protocol messages, completing the establishment of the passive routing table. The generated routing table entries include destination node information, next-hop node information, hop count information, and link quality information for each hop. The link quality information includes signal strength and signal-to-noise ratio. The establishment of the passive routing table is based on the following steps: Step 1: Obtain the geographical location information of this node and other nodes in the network. Nodes in the network can exchange geographical location information with other nodes based on the topology established through active routing, and form a set of geographical location information through periodic updates or location prediction. ,in, For the first in the network i The geographic location information of each node, which is used to calculate the distance between nodes, is latitude and longitude information and elevation information or projected coordinate position and elevation information; Step 2: Obtain device capability information for this node and other nodes in the network. Nodes in the network can exchange device capability information with other nodes based on the topology established through active routing, generating a set of device capability information. ,in, For the first in the network i The device capability information of each node is used as a parameter of the channel propagation model for estimating the link state between nodes. The device capability information includes the device's transmit power, antenna gain, operating frequency, and demodulation sensitivity. Step 3: Calculate the link status between each node in the network based on geographical location information and device capability information, forming a link status set. ,in, For nodes i and nodes j The link states between them are divided into connectionless states. N One-way connection state H and bidirectional connection status S The link state has weights M ; Step 4: Generate network topology graph: Using this node as the source node, select all links in the bidirectional connection state as edges to generate a network topology graph, where the link weights are... M The weights of the edges in the topological graph; Step 5: Based on the network topology diagram generated in Step 4, using this node as the source node and other nodes in the network as destination nodes, utilize... Dijkstra The algorithm calculates the optimal path and forms a set of preferred paths; Step 6: When a route loss event occurs or data packets need to be forwarded across clusters, the source node is triggered to send a route discovery request message. The route discovery request message carries the preferred path information generated in step 5. Nodes along the route use the preferred path as the forward propagation path to propagate the route discovery request information to the destination node. Step 7: After receiving the route discovery request message, the destination node sends a route discovery response message. The route discovery response message is propagated back to the source node along the preferred path. During the back propagation process, the nodes along the way add their own and their neighbor nodes' link quality information to the route discovery response message. The link quality information includes signal strength and signal-to-noise ratio. Step 8: After receiving the route discovery response message, the source node generates a route table entry and adds the route table entry to the passive routing table. The route table entry includes destination node information, next-hop node information, hop count information, and link quality information for each hop. The routing fusion module is used to merge the active routing table and the passive routing table. When there are paths to the destination node in both the active routing table and the passive routing table, the path with the fewest hops or the largest link weight is selected as the routing result and a forwarding routing table is generated.

4. A hybrid routing method based on the hybrid routing system of claim 3, characterized in that, Includes the following steps: Step 1: When an active or passive route generates a route update, a route update message is sent to the route fusion module; Step 2: After receiving the route update message, the route fusion module merges the active route table entries and the passive route table entries to obtain a set of all reachable destination nodes; Step 3: Traverse all reachable destination nodes, check whether the destination node has a routing table entry in the active routing table and passive routing table, and decide how to add the routing table entry to the forwarding routing table according to Step 4 and Step 5; Step 4: If an entry for reaching the destination node exists only in the active or passive routing table, then directly add the routing entry to the forwarding routing table. Step 5: If both the active routing table and the passive routing table contain routing entries leading to the destination node, then calculate the weights of the two routing table entries respectively. Q The path with the larger weight is selected as the optimal path, and the corresponding entry is added to the forwarding routing table.

5. The hybrid routing method according to claim 4, characterized in that, In step 5, the weight of the routing table entry is calculated. Q for: ， in, N This represents the hop count of the route. Let be the signal-to-noise ratio of the i-th hop. i =1,2,…, N .

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