Hop count threshold-based self-adaptive hybrid routing method for ad hoc network

Abstract

The invention belongs to the technical field of mobile ad hoc network communication, and discloses an ad hoc network adaptive hybrid routing method based on a hop count threshold, and the method comprises the steps: obtaining a routing hop count from a source node to a destination node; comparing the routing hop count with a preset hop count threshold value; according to a comparison result, different routing modes are selected for data transmission; wherein when the routing hop count is greater than the hop count threshold value, the AODV unicast routing mode is used for data transmission; when the routing hop count is smaller than or equal to the hop count threshold value, data transmission is carried out in a CBR broadcast routing mode; the technical problem that a single routing protocol cannot give consideration to short-range high reliability and long-range low overhead at the same time is solved, optimization and balance of the overall transmission performance of the network are achieved, the transmission reliability is improved, the network overhead is effectively reduced at the same time, and the method has the advantages of being high in compatibility and usability and wide in application scene.

Description

Technical Field

[0001] This invention belongs to the field of mobile ad hoc network communication technology, specifically relating to an adaptive hybrid routing method for ad hoc networks based on hop count threshold. Background Technology

[0002] Routing protocols in Mobile Ad-hoc Networks (MANETs) are crucial for ensuring multi-hop communication performance. Currently, mainstream routing schemes are mainly divided into two categories: on-demand unicast routing (such as Ad hoc On-Demand Distance Vector, AODV) and Controlled Barrage Region (CBR) technology.

[0003] The AODV protocol reduces overhead by discovering unicast paths on demand. Its core mechanism is to dynamically discover and establish a point-to-point unicast path only when nodes need to communicate, through the interaction of broadcast route requests (RREQ) and unicast route replies (RREP). While this mechanism effectively reduces the network overhead caused by periodic route advertisements, a complete route discovery process is still required for short-distance communication, introducing unnecessary latency and control overhead.

[0004] CBR (Continuous Broadcast Buffer) technology improves the reliability of short-range multicast / broadcast and achieves service flow isolation by constructing controlled broadcast areas. Its basic idea is to build a controlled, limited-range broadcast area between the source and destination nodes by controlling message interaction. Nodes within the area are divided into relay nodes (responsible for forwarding) and blocking nodes (suppressing forwarding), thereby achieving multi-flow isolation and avoiding network-wide flooding. However, the area construction parameters of existing CBR technologies are usually fixed, making it unable to adapt to dynamic changes in network topology and real-time fluctuations in link quality.

[0005] Therefore, neither the AODV protocol alone nor the CBR technology can meet the diverse transmission requirements in dynamic ad hoc networks: the AODV protocol has high overhead for short-distance communication, while the CBR technology has low reliability for long-distance communication, making it difficult to achieve a balance between high reliability and low overhead in different communication distance scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide an adaptive hybrid routing method for self-organizing networks based on a hop count threshold. By introducing a hop count threshold, the routing protocol can intelligently sense the communication distance and dynamically and adaptively switch between AODV unicast routing mode and CBR broadcast routing mode, so as to achieve a balance between high reliability and low overhead in different communication distance scenarios.

[0007] The present invention adopts the following technical solution: An adaptive hybrid routing method for ad hoc networks based on a hop count threshold includes the following steps: Get the number of hops from the source node to the destination node; Compare the route hop count with a preset hop count threshold; Based on the comparison results, different routing modes are selected for data transmission; When the number of hops exceeds the hop count threshold, AODV unicast routing mode is used for data transmission. When the number of hops is less than or equal to the hop count threshold, CBR broadcast routing mode is used for data transmission.

[0008] The beneficial effects of this invention are: by introducing a hop count threshold as a decision criterion, this invention enables the routing protocol to intelligently sense changes in communication distance and dynamically switch adaptively between the low-overhead AODV unicast routing mode and the high-reliability CBR broadcast routing mode; it solves the inherent contradiction that a single protocol cannot simultaneously achieve high reliability in the short term and low overhead in the long term, and realizes the optimization and balance of the overall network transmission performance. Attached Figure Description

[0009] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the controlled interception area establishment process in this invention; Figure 3 This is a schematic diagram of the controlled interception area in this invention. Detailed Implementation

[0010] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0011] The relevant terms in this invention are explained as follows: Route hop count: The number of intermediate nodes traversed in the data transmission path from the source node to the destination node; it is an indicator of path length.

[0012] Valid route entry: A route record stored in the node’s local routing table that is currently available for forwarding data. It must simultaneously satisfy the following conditions: (1) the entry exists; (2) the entry has not expired; and (3) the entry contains hop count information.

[0013] Route Request (RREQ) message: When no valid route exists, it is broadcast by the source node to discover a path to the destination node.

[0014] Route Reply (RREP) messages: These are unicast messages sent from the destination node or an intermediate node that knows the route to the source node along the reverse path established by the RREQ, and they carry the route hop count.

[0015] Controlled Interception Zone: In CBR mode, this is a logical broadcast transmission zone dynamically formed between the source and destination nodes through control message exchange. This zone is jointly defined by relay nodes and blocking nodes.

[0016] Intermediate node: A network node that, in addition to the source node and the destination node, can receive and process control messages and data packets on the path from the source node to the destination node.

[0017] Relay node: Within the controlled interception area of ​​the CBR, the node is identified as responsible for receiving and forwarding data packets and control messages.

[0018] Blocking nodes: Nodes at the edge of the controlled interception zone of the CBR that are determined to discard all data packets and control messages of this flow and not participate in forwarding.

[0019] Request To Send (RTS) messages: used for topology probing.

[0020] Buffer update (BUF) messages: used for early warning notifications.

[0021] Clear To Send (CTS) message: used to trigger role determination.

[0022] Controlled Interception Area Acknowledgment (CBRAck) message: Used to acknowledge the successful reception of data packets within a controlled intercept area, returned by the relay node or destination node via broadcast.

[0023] This invention provides an adaptive hybrid routing method for ad hoc networks based on a hop count threshold, such as... Figure 1 As shown, it includes the following steps: S100, preset hop count threshold and interception area parameters; the hop count threshold is used to determine the routing mode switching conditions, and the interception area parameters are used to determine the width of the interception area.

[0024] Specifically: S101, Hop Count Threshold Setting: The initial value of the hop count threshold is preset through network management commands (the default value is 5, and the value range is from 0 to the integer of the network diameter, which can be dynamically adjusted) to determine the conditions for switching routing modes.

[0025] Interception area parameter settings: The initial value of the preset interception area width parameter N (the default initial value is 1, and the value range is 0 to 5) is used to determine the size of the interception area width. The upper limit of the retransmission frequency is C1 (the default value is 0.1) and the lower limit is C2 (the default value is 0.2).

[0026] S102, Cache parameter settings: Set the lifetime of broadcast data cache entries (default is 2s), and the lifetime of RREQ hop count cache entries (default is 5s).

[0027] S103, Node Role Initialization: All nodes are initialized to the full-featured AODV node role by default.

[0028] S104, Local routing table initialization: Clear the local routing table, retaining only the entry corresponding to the node's own identifier.

[0029] S200: Get the number of hops from the source node to the destination node.

[0030] This includes: querying the local routing table; if a valid route entry to the destination node exists in the local routing table, then extracting the route hop count from the valid route entry; if no valid route entry exists, the source node broadcasts an RREQ message, and after receiving an RREP message from the destination node, extracts the route hop count between the source node and the destination node from the RREP message; where a valid route entry refers to a route entry that has not expired and contains hop count information.

[0031] Specifically: S201, Route query triggered: The node application layer initiates a data sending request, carrying the source node identifier, destination node identifier and business data, triggering the route hop count acquisition.

[0032] S202, Valid route determination: Query the local routing table to determine if there is a valid route entry to the destination node; the local routing table records the correspondence between the source node and the destination node, the hop count, and the link state parameters.

[0033] S203, Hop Count Extraction: If a valid route entry exists, the hop count information of that route is extracted directly from the valid route entry.

[0034] S204, Route Discovery Completion: If no valid route entry exists, the following route discovery process is executed: a. The source node broadcasts an RREQ message, which carries the source node identifier, destination node identifier, RREQ ID, and initial hop count of 0.

[0035] b. When an intermediate node forwards an RREQ message, it updates the hop count field, increments the current hop count by 1, and records the reverse route, recording the path from the source node to the current intermediate node.

[0036] c. After receiving the RREQ message, the destination node unicasts an RREP message in response. The RREP message carries the shortest hop count between the source node and the destination node.

[0037] d. After receiving the RREP message, the source node establishes a forward route and updates its local routing table, extracting the hop count from the local routing table.

[0038] In this invention, the hop count is obtained by querying the local routing table, enabling extremely fast response to data transmission requests. When a route is valid, existing path information can be directly utilized, avoiding the control overhead and latency caused by route discovery for every communication, thereby improving the overall network efficiency. When a valid route is lacking, the hop count is obtained by triggering a standard route discovery process, ensuring the reliability and reachability of the routing information. This mechanism is the fundamental guarantee for obtaining the route hop count, ensuring that the adaptive decision-making system can obtain the necessary path information to make the correct mode selection under any circumstances (especially after new communication or drastic topology changes).

[0039] S300 compares the route hop count with a preset hop count threshold.

[0040] S400 selects different routing modes for data transmission based on the comparison results; when the number of route hops is greater than the hop count threshold, the AODV unicast routing mode is used for data transmission; when the number of route hops is less than or equal to the hop count threshold, the CBR broadcast routing mode is used for data transmission.

[0041] If a route failure is detected during data transmission via AODV unicast routing mode or CBR broadcast routing mode, the route hop count from the source node to the destination node is re-acquired, and the steps of comparing and selecting the routing mode are re-executed.

[0042] In this invention, when a route failure is detected, the system does not simply attempt to repair the original path, but triggers a completely new global decision-making process to reselect the optimal routing mode based on the latest network topology. This "closed-loop maintenance" mechanism significantly improves the robustness and adaptability of the network in dynamically changing environments.

[0043] Specifically: S401: When the number of hops exceeds the hop count threshold, AODV unicast routing mode is used to transmit data.

[0044] Due to the high number of routing hops, using AODV unicast routing mode for long-distance data transmission can reduce network redundancy overhead. The specific process is as follows: a. Route establishment confirmation: Confirm that a valid route entry exists in the local routing table.

[0045] b. Data packet construction: The source node constructs unicast data packets. The packet header carries the source node identifier, destination node identifier, next-hop address, protocol type and data length, and the data part is business data.

[0046] c. Hop-by-hop forwarding: The source node sends the data packet to the next-hop intermediate node. After receiving the packet, the next-hop intermediate node queries its local routing table to determine the next-hop address corresponding to the intermediate node and continues to forward the packet until it reaches the destination node.

[0047] d. Route maintenance: During data transmission, the signal strength, transmission delay, and packet loss rate of each hop link are monitored in real time to determine link breakage and trigger route updates.

[0048] e. The broken node sends a Route Error (RERR) message to the source node to inform it that the route has failed; after receiving the RERR message, the source node deletes the failed route entry, re-executes the route discovery process in step S200, obtains the new route hop count, and then re-enters the route mode determination in steps S300 and S400.

[0049] f. Transmission confirmation: After receiving the data packet, the destination node returns a unicast confirmation message to the source node according to the service requirements. The source node determines that the transmission was successful after receiving the confirmation.

[0050] S402: When the number of hops is less than or equal to the hop count threshold, CBR broadcast routing mode is used to transmit data.

[0051] Because the number of routing hops is relatively small, the CBR broadcast routing mode can improve transmission reliability and multi-flow isolation when performing short-distance transmission. The specific process includes three stages: controlled interception area construction, data broadcast transmission, and area disbandment.

[0052] Phase 1: Controlled Interception Zone Construction. A controlled interception zone is constructed between the source node and the destination node. Specifically: ... Figure 2 As shown, the process involves using RTS / BUF / CTS three-color control message interaction to define intermediate node roles and construct a limited interception zone. The workflow is as follows: a. Source node broadcasts RTS message: The source node generates an RTS message, using a 16-bit random integer for the flow identifier to ensure uniqueness of identifiers for different flows within the network. The hop count field is set to 0, and the transmission power is set to maximum to ensure coverage of all potential nodes between the source and destination nodes. The source node broadcasts the RTS message to notify surrounding nodes that it is about to start CBR broadcast routing mode to transmit data. The RTS message includes hop count information from the source node to other nodes; other nodes are intermediate nodes or destination nodes. A first timer is started, and if no CTS message is received after the first timer expires, the RTS message is rebroadcast.

[0053] b. Intermediate nodes receive and forward RTS packets: When an intermediate node receives an RTS packet for a certain flow for the first time, it parses the RTS packet, extracts the source node identifier, flow identifier, and hop count to the source node, stores them in the local mapping table, updates the hop count in the RTS packet, and then forwards it via broadcast. If the intermediate node receives an RTS packet for the same flow again, it discards it directly to avoid duplicate forwarding.

[0054] c. BUF / CTS message feedback: When the destination node receives the RTS message for the first time, it records the shortest hop count between the source node and the destination node and starts the second and third timers.

[0055] Before the second timer expires, the destination node continues to receive RTS messages and records the number of hops to the source node, and finally retains the shortest number of hops from the destination node to the source node.

[0056] After the second timer expires, the destination node broadcasts a BUF message to inform surrounding nodes that an interception zone is about to be built.

[0057] Before the third timer expires, nodes that receive BUF messages but not RTS messages will be identified as the first blocking nodes and will enter the interception preparation state in advance.

[0058] After the third timer expires, the destination node broadcasts a CTS message, which means that sending a notification is allowed. The CTS message carries the source node identifier, destination node identifier, flow identifier, shortest hop count, and hop count to the destination node of 0.

[0059] d. Intermediate Node Role Determination: When an intermediate node receives a CTS message for the first time, it parses the CTS message, extracts the destination node identifier, flow identifier, and hop count to the destination node, stores them in the local mapping table, and updates the hop count in the CTS message.

[0060] The intermediate node queries its local mapping table to obtain the hop count from the intermediate node to the source node, the hop count from the intermediate node to the destination node, and the shortest hop count. The criteria for determining the hop count are as follows: X+Y≤δ+N, Where X is the number of hops from the intermediate node to the source node, Y is the number of hops from the intermediate node to the destination node, δ is the shortest number of hops, and N is the interception area width parameter.

[0061] If an intermediate node meets the determination criteria, it is determined to be a relay node and continues to broadcast and forward CTS messages, possessing the authority to forward the data packets of that flow.

[0062] If an intermediate node does not meet the judgment criteria, it is determined to be a second blocking node, and the forwarding of CTS messages is stopped. The interception mechanism is activated, and the forwarding of all subsequent data packets and control messages in the flow is rejected.

[0063] Intermediate nodes that do not receive CTS messages are considered irrelevant nodes and will not participate in any transmission process of the stream.

[0064] A controlled interception area is formed by using relay nodes, first blocking nodes, and second blocking nodes.

[0065] e. Role Synchronization: After the intermediate node completes the role determination, it synchronizes the intermediate node's role status to all neighboring nodes through periodic HELLO messages. The neighboring nodes update the "role identifier" field in their routing tables to ensure consistency in routing decisions.

[0066] Controlled interception area such as Figure 3 As shown in the figure, S Indicates the source node, D Indicates the destination node. B The symbols represent blocking nodes (including the first and second blocking nodes). 1 indicates a relay node with a distance of one hop from the source node, 2 indicates a relay node with a distance of two hops from the source node, and 3 indicates a relay node with a distance of three hops from the source node. U Indicates an irrelevant node.

[0067] In this invention, by introducing a collaborative interaction process involving three control messages—RTS, BUF, and CTS—and three timers, the construction process of the controlled interception zone is made highly ordered and conflict controllable. The first timer ensures that the source node can resend the message if the destination node does not receive it; the second timer ensures that the destination node can collect the optimal path information; and the third timer provides a buffer time for node role switching, thereby significantly improving the success rate and stability of zone construction.

[0068] Meanwhile, by having intermediate nodes autonomously determine their roles based on received message information, the distributed and automated construction of controlled interception zones is achieved. Nodes can determine their own behavior (relay or block) solely through local computation, without the need for centralized control. This makes the zone construction process highly scalable and adaptable, perfectly matching the distributed characteristics of ad hoc networks.

[0069] Phase 2: Data Broadcast Transmission. The source node broadcasts data packets within the controlled interception area, transmitting the data to the destination node. Specifically, after the controlled interception area is constructed, the data transmission phase begins. Reliability is ensured through confirmation via flow identifiers and CBRAck messages. The process is as follows: a. Data packet construction: The source node constructs broadcast data packets. The packet header carries the source node identifier, destination node identifier, stream identifier, packet sequence number and data length. The data part is business data; the data includes several data packets.

[0070] b. Broadcast transmission: The source node broadcasts data packets at a preset power and simultaneously initiates an acknowledgment time window.

[0071] c. Packet reception and processing: After successfully receiving a data packet, the relay node and the destination node return a CBRAck message to the source node via broadcast.

[0072] If the source node receives a CBRAck message from the destination node, the data transmission is successful.

[0073] If the source node does not receive a CBRAck message from the destination node, data transmission fails, meaning the current route is invalid.

[0074] Specifically: After receiving a data packet, the relay node first performs a duplicate data check. If there are entries with the same flow identifier, packet sequence number, source node identifier, and destination node identifier, the packet is determined to be a duplicate and is discarded directly. If there are no entries with the same flow identifier, packet sequence number, source node identifier, and destination node identifier, the packet is processed and forwarded immediately, and a CBRAck message is returned via broadcast to confirm the packet.

[0075] e. After receiving a data packet, the destination node performs a duplicate data check: if it is a non-duplicate packet, it processes the business data and returns a CBRAck message to acknowledge the packet; if it is a duplicate packet, it is discarded directly; if the blocking node or an unrelated node receives a data packet, it is discarded directly without forwarding or returning an acknowledgment.

[0076] f. Retransmission decision: The source node counts CBRAck packet groups within the acknowledgment time window. If it receives a CBRAck packet from the destination node, it determines that the packet transmission was successful and proceeds to the next packet transmission. If the source node does not receive any CBRAck packets, or fails to receive any packets after 3 retransmissions, it determines that the transmission has failed and re-executes steps S200 to S400.

[0077] g. Cache update: After all receiving nodes have processed the data packets, they add a new entry to the broadcast data cache table, recording the stream identifier, packet sequence number, source node identifier, destination node identifier, and current timestamp, and start the lifecycle timer.

[0078] In this invention, a CBR (Continuous Broadcast Response) message is broadcast to the source node via relay nodes and the destination node. The source node determines the success or failure of the transmission based on the acknowledgment from the destination node, introducing an efficient, receiver-based reliable transmission guarantee mechanism for the CBR broadcast mode. This not only improves the reliability of data transmission, but its broadcast acknowledgment method also simplifies reverse path maintenance, matching the broadcast characteristics of CBR.

[0079] Phase 3: Region Disbandment. After data transmission is complete, the controlled interception region is disbanded. Specifically, when data transmission is complete or the flow is interrupted, the interception region is disbanded, and node resources are released. The process is as follows: a. Disbandment trigger condition: Transmission complete: The source node has sent all service packets and received the corresponding CBRACK messages from the destination node within the acknowledgment time window.

[0080] Transmission failure: If a packet is retransmitted 3 times but no acknowledgment is received from the destination node, the flow is determined to be interrupted.

[0081] Stream timeout: No data packets are sent after the stream is established and the preset timeout period has elapsed.

[0082] b. Disband command transmission: The source node broadcasts a controlled interception zone disband (CBRTearDown) message, carrying the source node identifier, destination node identifier, and flow identifier, to notify all nodes to disband the current flow's interception zone.

[0083] c. Node resource release: Relay Node: Delete the broadcast data cache entry, RREQ hop count cache entry, and role mapping table corresponding to this stream, and restore it to a normal full-featured AODV node role.

[0084] Blocking Node: Disables the blocking mechanism, deletes all associated cache entries and mapping tables for this stream, and restores it to the normal full-featured AODV node role.

[0085] Irrelevant nodes: Only delete the broadcast data cache entry and RREQ hop count cache entry corresponding to the stream; the role status remains unchanged.

[0086] d. Node reuse: After a region is dissolved, all nodes can participate in the construction of controlled interception regions for other flows, supporting dynamic scheduling and resource reuse of multiple flows.

[0087] In this invention, the controllable interception area is disbanded by triggering the immediate release through the CBRTearDown message, thereby realizing the immediate reclamation and deterministic reuse of network resources. This fundamentally ensures the efficiency of the CBR mechanism, the reliability of multi-stream parallel transmission, and the rapid response capability of the entire adaptive network to dynamic services.

[0088] The present invention also provides an adaptive hybrid routing device for ad hoc networks based on a hop count threshold, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement any of the above methods.

[0089] To achieve the integration of AODV unicast routing mode and CBR broadcast routing mode, and to solve the problems of multi-flow isolation, controlled interception area construction, and reliable transmission, this invention designs three types of core control messages. Each type of message has independent functions yet works in a coordinated and orderly manner, summarized as follows: Message 1: RREQ message.

[0090] As shown in Table 1, Table 1 is the structure of the routing request header.

[0091] Table 1. Routing Request Header Structure

[0092] The length and function of each part in the table are as follows: Type: 8 bits in length; identifies the message type.

[0093] J: Length 1 bit; Include flag, reserved for multi-target transmission.

[0094] R: 1 bit length; repair flag, reserved for multi-target transmission.

[0095] G: Length 1 bit; Unsolicited RREP flag, indicating whether an unsolicited RREP packet needs to be sent to the node determined by the destination node's IP address field in a single-target manner. Setting it to 1 indicates that it is needed, and clearing it to 0 indicates that it is not needed.

[0096] D: Length 1 bit; a node flag for a single destination, indicating that only one node can respond to this RREQ message.

[0097] U: Length 1 bit; Unknown sequence number, indicating that the node sequence number for this purpose is an unknown sequence number.

[0098] Reserved: 11 bits in length; set to 0 when sending and not processed when receiving.

[0099] Hop Count: 8 bits long; indicates the number of forwarding hops from the source node IP address to the node that processes this RREQ message.

[0100] Route Request Identifier (RREQ ID): This is a sequence number; the RREQ ID and the source node IP address can be used to uniquely identify an RREQ message.

[0101] Destination node sequence number: The latest sequence number of the destination node that the source node has received and that has been reached by any route.

[0102] Source node IP address: The IP address of the node that generated this RREQ message.

[0103] Source node sequence number: The current sequence number in a routing entry that is being used and that points to the source node of this RREQ message.

[0104] Message 2: CBRAck message, used to intercept controlled area route construction reply control messages.

[0105] As shown in Table 2, Table 2 shows the control header structure for constructing controlled interception areas.

[0106] Table 2 Control Header Structure for Controlled Interception Area Construction

[0107] The length and function of each part in the table are as follows: Source node IP address: This indicates the IP address of the node that initially initiated the route discovery request; this address identifies the initiator of the entire route discovery process, and the acknowledgment (ACK) message must eventually be delivered to this address.

[0108] Destination node IP address: Indicates the IP address of the final target node that the original routing request wants to communicate with.

[0109] Route Request ID: This is a sequence number that corresponds to the ID in the original RREQ message. This ID allows the receiver to uniquely identify which specific route request the ACK is a response to, thus matching requests and responses.

[0110] RREQ Hop Count: 8 bits in length; indicates the number of hops the corresponding RREQ message takes from its original source address to the node that generated this ACK. This value reflects the length of the forward path.

[0111] ACK Hop Count: 8 bits long; indicates the number of hops this ACK message traverses during its return journey from the generating node. This value increments each time the ACK message is forwarded through a node, recording the length of the return path.

[0112] Message 3: CBRTearDown message.

[0113] As shown in Table 3, Table 3 is the structure of the disbanding control header for the controlled interception area.

[0114] Table 3. Controlled Interception Area Disband Control Header Structure

[0115] The functions of each part in the table are as follows: Source node IP address: This indicates the IP address of the node that initially initiated the routing request. This address identifies the initiator of the entire route discovery process, and the ACK message must eventually be delivered to this address.

[0116] Destination node IP address: Indicates the IP address of the final target node that the original routing request wants to communicate with.

[0117] In summary, compared with the prior art, the present invention has the following significant advantages: 1. Significantly improved transmission reliability: In CBR broadcast routing mode, through controlled interception areas and CBRAck message confirmation mechanism, the success rate of short-distance transmission is improved by more than 20%, and the packet loss rate is reduced to below 5%.

[0118] 2. Network overhead is effectively reduced: Long-distance transmission adopts AODV unicast routing mode to avoid broadcast redundancy, reducing the overall network overhead by more than 15%.

[0119] 3. Strong compatibility and ease of use: Compatible with standard AODV protocol, it can be seamlessly connected to existing AODV networks; core parameters (hop count threshold, N value) are simple to configure, requiring no complex algorithm adaptation, and are easy to deploy.

[0120] 4. Wide range of applicable scenarios: It is suitable for various self-organizing network scenarios such as unmanned cluster collaboration and emergency rescue, and is especially suitable for the mixed transmission needs of short-distance high reliability and long-distance low overhead.

[0121] Therefore, this invention dynamically selects AODV unicast or CBR broadcast mode by comparing the number of communication hops with a threshold, so as to optimize long-distance overhead and short-distance reliability respectively. The CBR mode constructs a reliable controlled broadcast area through innovative control interaction and confirmation mechanism; effectively solving the performance limitations of a single protocol, and significantly improving the transmission efficiency and overall reliability of dynamic self-organizing network.

Claims

1. A self-organizing network adaptive hybrid routing method based on hop count threshold, characterized in that, Includes the following steps: Get the number of hops from the source node to the destination node; The routing hop count is compared with a preset hop count threshold; Based on the comparison results, different routing modes are selected for data transmission; When the number of hops in the route exceeds the hop count threshold, AODV unicast routing mode is used for data transmission. When the number of hops in the route is less than or equal to the hop count threshold, the CBR broadcast routing mode is used for data transmission.

2. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 1, characterized in that, The method further includes: During data transmission via the AODV unicast routing mode or CBR broadcast routing mode, if the current route is detected to be invalid, the route hop count from the source node to the destination node is re-acquired, and the steps of comparing and selecting the routing mode are re-executed.

3. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 2, characterized in that, Obtaining the route hop count from the source node to the destination node includes: Query the local routing table; If a valid route entry to the destination node exists in the local routing table, then the route hop count is extracted from the valid route entry; The valid routing entry refers to a routing entry that has not expired and contains hop count information.

4. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 3, characterized in that, If no valid route entry exists, the source node broadcasts an RREQ message and, upon receiving an RREP message from the destination node, extracts the route hop count between the source and destination nodes from the RREP message.

5. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 4, characterized in that, Data transmission using CBR broadcast routing mode includes: A controlled interception zone is established between the source node and the destination node; The source node broadcasts data packets within the controlled interception area, transmitting the data to the destination node; the data includes several data packets. After the data transmission is completed, the controlled interception area is disbanded.

6. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 5, characterized in that, Establishing a controlled interception zone between the source node and the destination node includes: The source node broadcasts an RTS message and starts a first timer; the RTS message includes hop count information from the source node to other nodes; the other nodes are intermediate nodes or destination nodes. The intermediate node that receives the RTS message forwards the RTS message and records the number of hops from the intermediate node to the source node; After the destination node receives the RTS message for the first time, it starts the second and third timers. Before the second timer expires, the destination node continues to receive RTS messages and records the number of hops to the source node, and finally retains the shortest number of hops from the destination node to the source node; After the second timer expires, the destination node broadcasts a BUF message; Before the third timer expires, the node that receives the BUF message but does not receive the RTS message is identified as the first blocking node. After the third timer expires, the destination node broadcasts a CTS message; the CTS message includes the shortest hop count and the hop count information from the destination node to other nodes; If the source node still does not receive the CTS message after the first timer expires, the source node will rebroadcast the RTS message.

7. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 6, characterized in that, After the destination node broadcasts the CTS message, it also includes: The intermediate node receives CTS messages and records the number of hops from the intermediate node to the destination node; The determination criteria are constructed based on the number of hops from the intermediate node to the source node, the number of hops from the intermediate node to the destination node, and the shortest number of hops. If the intermediate node meets the determination condition, then the intermediate node is determined to be a relay node; If the intermediate node does not meet the determination condition, then the intermediate node is determined to be the second blocking node; The relay node, the first blocking node, and the second blocking node are used to form a controlled interception area.

8. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 7, characterized in that, The determination criteria are as follows: X+Y≤δ+N, Where X is the number of hops from the intermediate node to the source node, Y is the number of hops from the intermediate node to the destination node, δ is the shortest number of hops, and N is the interception area width parameter.

9. The self-organizing network adaptive hybrid routing method based on hop count threshold according to claim 8, characterized in that, Transmitting the data to the destination node includes: After successfully receiving the data packet, the relay node and the destination node return a CBRAck message to the source node via broadcast. If the source node receives a CBRAck message from the destination node, the data transmission is successful; If the source node does not receive a CBRAck message from the destination node, the data transmission fails, meaning the current route is invalid.

10. An adaptive hybrid routing device for ad hoc networks based on a hop count threshold, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-9.

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