Converging reactive routing and DTN message transmission methods and storage media

Abstract

This invention specifically relates to a message transmission method and storage medium that integrates reactive routing and DTN. The method includes: when a source node transmits a message to a destination node: first, it broadcasts a routing request message in the network using the reactive MANET routing protocol mechanism; upon receiving a routing response message, it transmits the message to the source node; upon receiving a routing error message, it uses the DTN mechanism to allocate a copy of the message to a relay node at the topology boundary of the source node, making it a virtual source node; if message transmission fails, it stores a copy of the message at the relay node where the communication link is interrupted, making it a virtual source node; the virtual source node broadcasts routing solicitation information to its neighboring nodes, and repeats the above steps when an opportunity to establish a connection with the destination node is found. This invention can improve the reliability of message transmission through the DTN routing mechanism and fully explore the connectable subtopologies in the MANET network.

Description

Technical Field

[0001] This invention relates to the field of wireless network protocol technology, specifically to a message transmission method and storage medium that integrates reactive routing and DTN. Background Technology

[0002] Reactive routing protocols, also known as on-demand routing protocols, are specifically designed for MANET (Mobile Ad Hoc Network) environments. Unlike table-driven routing protocols, these protocols do not pre-generate all routes; instead, they establish routes only when needed by the source node. In other words, the node's routing table information is built on demand, and it may only contain a portion of the overall topology information. Reactive routing generally includes two phases: route discovery and route maintenance.

[0003] The main differences between reactive routing protocols lie in the route discovery process, the methods for obtaining and maintaining routing information, and the way data is transmitted. Compared to proactive routing protocols, reactive routing protocols do not need to periodically maintain unused routes; they only need to acquire routes when data is being sent. Therefore, they generate far less routing control information than proactive routing protocols. However, because routes must be acquired before data transmission, there is a certain startup delay. Therefore, reactive routing protocols are suitable for situations where the network load is not too heavy and the node movement speed is not too fast.

[0004] In existing technologies, message transmission methods based on reactive MANET routing protocols are prone to network disconnection issues. This occurs when a message sent by a source node reaches a relay node, but the next-hop node suddenly disconnects for some reason, preventing the message or message copy from being effectively transmitted to the destination node. To address this problem, existing technologies typically integrate multiple routing protocols for message transmission. When the reactive MANET routing connection is lost, a serial switching mechanism switches to another routing strategy to complete message transmission. However, while existing multi-routing protocol integration schemes ensure message transmission reliability to some extent, their method of directly switching routing strategies at the source node does not fully explore the connectable sub-topologies within the MANET, resulting in low utilization of the network's connectable topologies. Therefore, designing a method that efficiently utilizes the connectable topologies in a MANET network to improve message transmission reliability is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a message transmission method that integrates reactive routing and DTN, so as to improve the reliability of message transmission through the DTN routing mechanism, fully explore the connectable sub-topologies in the MANET network, and thus improve the utilization rate of the connectable topologies in the reactive MANET, thereby ensuring the stability and practicality of message transmission.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] The message transmission method, which integrates reactive routing and DTN, is used when a message source node transmits a message to a message destination node:

[0008] S1: First, use the reactive MANET routing protocol mechanism to broadcast routing request information in the network;

[0009] S2: Receive routing response information from the message destination node or routing error information from the relay node at the point of communication link interruption through the message source node; if routing response information is received, transmit the message to the message source node; if routing error information is received, distinguish between different communication connection conditions and use the DTN mechanism to distribute message copies to the relay nodes at the topology boundary of the message source node to make them virtual source nodes.

[0010] S3: Determine whether the message in transmission has been successfully delivered to the message destination node: if yes, the message transmission is successful; otherwise, store a copy of the message at the relay node where the communication link is interrupted, making it a virtual source node.

[0011] S4: The virtual source node searches for the message destination node by broadcasting routing query information to its neighboring nodes. When an opportunity to establish a connection with the message destination node is found, it jumps to step S2 until the message transmission is completed.

[0012] Preferably, if the message source node receives routing response information from the message destination node, then the following message sending strategy one is used:

[0013] S01: Send the message to the destination node, and then determine whether the message was sent successfully: if yes, proceed to step S07; otherwise, proceed to step S02.

[0014] S02: Store a copy of the message at the relay node at the point of interruption, making it a virtual source node;

[0015] S03: The virtual source node will periodically or eventually send a query message containing the identifier of the destination node of the message to the neighboring nodes;

[0016] S04: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and then jumps to step S07; otherwise, the neighboring node broadcasts routing request information and jumps to step S05.

[0017] S05: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighboring node through the destination node of the message, and jumps to step S06; otherwise, the neighboring node replies the routing error information to the virtual source node, and jumps to step S03.

[0018] S06: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S01; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S03.

[0019] S07: Message sent successfully.

[0020] Preferably, the routing error information includes the location information of the relay node at the point of interruption, and the location information is generated through the following two location strategies;

[0021] Location Strategy 1: Gridded location information obtained with the assistance of satellite positioning systems;

[0022] Location strategy 2: Logical location information based on routing tables.

[0023] Preferably, location strategy one generates location information through the following steps:

[0024] 1) A planar map of the network architecture region is pre-embedded, and the side length of the grid within the network architecture region is r;

[0025] 2) Nodes map their geographical location onto a planar map using the satellite positioning system, obtaining their location coordinates (x, y). i ,y i );

[0026] 3) Number the grids within the network architecture region, determine the reference node's position coordinates as (x0, y0) and the grid position number as (1, 1), where x0 ≤ x i y0≤y i ;

[0027] 4) Calculate the node (x) using the following formula. i ,y i The grid position (p) i ,q i ) as its location information;

[0028]

[0029]

[0030] In the formula: [] is the integer symbol, indicating that the smallest integer is selected.

[0031] Preferably, location strategy two refers to the virtual location information established by logical deduction based on the routing table, the node hop count in the neighbor table, and the number of neighbor nodes maintained in the ad hoc network routing protocol when a node in the network cannot obtain its own geographical location information through the satellite positioning system.

[0032] Preferably, if the message source node receives routing error information from the relay node at the point of interruption, then the following message sending strategy two is used:

[0033] S11: Determine whether the location information of the relay node is generated based on location strategy one: if yes, proceed to step S12; otherwise, proceed to step S13.

[0034] S12: Let the number of message replicas be n, then determine the number of nodes that the message source node can connect to be N, and determine whether there exists N>n-1: If yes, then select the outermost n nodes that are evenly distributed in all directions from the connectable nodes as virtual source nodes to store message replicas, and jump to step S15; otherwise, jump to step S13.

[0035] S13: Store a copy of the message in each relay node that sent the routing error information, making it a virtual source node, and then proceed to step S15;

[0036] S14: Send the message to the destination node, and then determine whether the message was sent successfully: if yes, proceed to step S19; otherwise, proceed to step S15.

[0037] S15: The virtual source node periodically or eventually sends a query message containing the destination node identifier to its neighboring nodes;

[0038] S16: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and jumps to step S19; otherwise, the neighboring node broadcasts routing request information, and jumps to step S17.

[0039] S17: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighbor node and jumps to step S18; otherwise, the neighbor node replies the routing error information to the virtual source node and jumps to step S15.

[0040] S18: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S14; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S15.

[0041] S19: Message sent successfully.

[0042] Preferably, in step S12, if N>n-1, the virtual source node is determined through the following steps:

[0043] S121: Calculate the grid position (p0, q0) of the centroid of the internal grid using the following formula;

[0044]

[0045]

[0046] In the formula: (p i ,q i () indicates the grid position of a node within the topology;

[0047] S122: Calculate the vector X between each node in the topology and the centroid using the following formula. i ,(i=1,2…N);

[0048] X i =(p i -p0,q i -q0), (i = 1, 2…N);

[0049] S123: Let the number of message replicas be n. Then, the message source node retains one message replica and becomes a virtual source node. Then, with vector X1 as the axis, calculate the angle between the vector of each node in the network architecture region and vector X1.

[0050]

[0051] S124: Establish a set of reference angles Then the included angle The nodes in the (n-1) grid positions that are closest to the elements in the reference angle set are used as virtual source nodes.

[0052] Preferably, in step S124, if there are multiple nodes in the same grid location, the functions of each node are considered to be equivalent, and any node is selected as the virtual source node.

[0053] Preferably, when the message source node broadcasts routing request information, there is a broadcast time threshold. If the message source node does not receive any message after the broadcast time threshold is reached, the message source node broadcasts a copy of the message to neighboring nodes until the message is delivered or the message's lifespan expires.

[0054] The present invention also discloses a readable storage medium storing a computer management program thereon, which, when executed by a processor, implements the steps of the converged reactive routing and DTN message transmission method as described in the present invention.

[0055] The message transmission method that integrates reactive routing and DTN in this invention has the following beneficial effects:

[0056] This invention transmits messages using a reactive MANET routing protocol, enabling the message source node to establish a connection with the message destination node via a "handshake" before sending the message. On the one hand, the message transmission method based on reactive routing can greatly reduce routing control information, thereby improving the efficiency of message transmission. On the other hand, the method of establishing a connection between the message source node and the message destination node in advance through a handshake can effectively ensure the accuracy of network connection and message transmission, thereby improving the stability of message transmission.

[0057] This invention receives and forwards message copies through the DTN routing mechanism when reactive MANET routes are disconnected, thereby improving the reliability of message transmission. Furthermore, unlike existing reactive MANETs that directly switch routing strategies upon disconnection, this invention designs virtual source nodes to broadcast route solicitation messages to neighboring nodes. This allows the virtual source nodes to continuously seek connectable subtopologies, maximizing the utilization of connectable subtopologies. In other words, it fully explores connectable subtopologies within the MANET network, thereby improving the utilization rate of connectable topologies in the MANET and ultimately enhancing the practicality of message transmission.

[0058] This invention incorporates node location information obtained through a satellite positioning system into the routing response and error information received by the reactive routing message source node. This location information is further processed to form a gridded location information structure. Unlike the replica allocation method in the existing spray-wait protocol's spray phase, this invention designs a gridded virtual source node allocation algorithm based on different location strategies. Specifically, it selects the outermost nodes, evenly distributed in all directions, from the connectable nodes as virtual source nodes. This allows for more accurate and effective determination of virtual source nodes, reducing network load caused by redundant information. This invention uses virtual source nodes to better seek connectable sub-topologies, thereby maximizing the utilization of connectable sub-topologies. Specifically, it can fully explore the connectable sub-topologies in the MANET network, thus further improving the utilization rate of reactive MANET routing.

[0059] This invention provides two location strategies based on whether satellite system geographic location information can be obtained, making it more suitable for message transmission needs in different scenarios, thereby improving the stability and practicality of message transmission. Attached Figure Description

[0060] To make the objectives, technical solutions, and advantages of the invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0061] Figure 1 A flowchart for message sending strategy one;

[0062] Figure 2 A flowchart for generating location information for location strategy one;

[0063] Figure 3 A flowchart for generating location information for location strategy two;

[0064] Figure 4 A flowchart for message sending strategy two;

[0065] Figure 5 This is a flowchart for determining virtual source nodes based on location-based strategy one. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but only to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0067] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0068] The following detailed explanation illustrates the specific implementation methods:

[0069] Example 1:

[0070] This embodiment discloses a message transmission method that integrates reactive routing and DTN.

[0071] The message transmission method, which integrates reactive routing and DTN, is used when a message source node transmits a message to a message destination node:

[0072] S1: First, the reactive MANET (Mobile Ad Hoc Network) routing protocol mechanism is used to broadcast route request information (RREQ) in the network;

[0073] S2: Receive route reply information (RREP) from the message destination node or route error information (RREP) from the relay node at the point of communication link interruption through the message source node; if route reply information is received, transmit the message to the message source node; if route error information is received, distinguish between different communication connection conditions, and use the DTN mechanism to distribute message copies to the relay nodes at the topology boundary of the message source node to make them virtual source nodes;

[0074] S3: Determine whether the message in transmission has been successfully delivered to the message destination node: if yes, the message transmission is successful; otherwise, store a copy of the message at the relay node where the communication link is interrupted, making it a virtual source node.

[0075] S4: The virtual source node searches for the message destination node by broadcasting routing query information to its neighboring nodes. When an opportunity to establish a connection with the message destination node is found, it jumps to step S2 until the message transmission is completed.

[0076] In this embodiment, when the message source node broadcasts routing request information, there is a broadcast time threshold. If the message source node does not receive any message after the broadcast time threshold is reached, the message source node broadcasts a copy of the message to neighboring nodes until the message is delivered or the message's lifespan is exhausted.

[0077] It should be noted that reactive MANET routing protocols refer to reactive mobile ad hoc network routing protocols. Among them, the On-Demand Plane Distance Vector Routing Protocol (AODV) is a classic reactive MANET routing protocol: When a node in the network wants to send a data packet, it first checks whether it has a route to the message's destination node. If it does, it forwards the data packet directly; otherwise, it sends a routing request via multicast. This request records the network layer addresses of the source and destination nodes. Upon receiving this routing request, neighboring nodes first determine whether they are the destination node. If they are, they send a routing response to the source node; otherwise, they iteratively check whether they have a route to the destination node, repeating this process until the data packet is forwarded to the destination node.

[0078] DTN routing mechanism refers to the delay-tolerant network routing mechanism. Delay-Tolerant Network (DTN) is a self-organizing network that utilizes node movement to create contact opportunities to transmit information even when there is no source-to-end connectivity. DTN adds a "carry-carry" element to the traditional "store-and-forward" message exchange mechanism of ad hoc networks, forming a "store-carry-forward" mechanism. That is, after a node receives a message, if it determines that there is no suitable next-hop forwarding node, it stores the message in its local buffer and then "carries" the message until a suitable forwarding opportunity is found to send the message.

[0079] For details, please refer to the jet waiting scheme in the DTN routing mechanism.

[0080] The Spray-and-Wait scheme is a routing protocol strategy based on controlling the number of flooded replicas. This strategy consists of two phases: Spray and Wait.

[0081] In the Spray phase: the message source node will generate L copies of the message and propagate the message copies to other relay nodes it comes into contact with until the number of message copies is 1, after which it will enter the Wait phase;

[0082] During the Wait phase: If the relay node carrying a copy of the message is unable to transmit the message to the message destination node during the Spray phase, the relay node will carry the message copy until it comes into contact with the message destination node to transmit the message.

[0083] This invention transmits messages using a reactive MANET routing protocol, enabling the message source node to establish a connection with the message destination node via a "handshake" before sending the message. On the one hand, the message transmission method based on reactive routing can greatly reduce routing control information, thereby improving the efficiency of message transmission. On the other hand, the method of establishing a connection between the message source node and the message destination node in advance through a handshake can effectively ensure the accuracy of network connection and message transmission, thereby improving the stability of message transmission.

[0084] Secondly, this invention receives and forwards message copies through the DTN routing mechanism when reactive MANE routes are disconnected, thus improving the reliability of message transmission. Furthermore, unlike existing reactive MANE systems that directly switch routing strategies when routes are disconnected, this invention designs virtual source nodes to broadcast route solicitation messages to neighboring nodes. This allows the virtual source nodes to continuously seek connectable sub-topologies, maximizing the utilization of connectable sub-topologies. In other words, it fully explores connectable sub-topologies in the MANET network, thereby improving the utilization rate of connectable topologies in the MANET and ultimately enhancing the practicality of message transmission.

[0085] Combination Figure 1 As shown, if the message source node receives routing response information from the message destination node, then the following message sending strategy one is used:

[0086] S01: Message source node N s To the message destination node N d Send the message, then determine if the message was sent successfully: if yes, proceed to step S07; otherwise, proceed to step S02; (The reason for message failure is: the message did not reach relay node N) v Its next-hop node suddenly disconnected due to special reasons.

[0087] S02: Store a copy of the message at the relay node (or intermediate node) where the interruption occurred. v This makes it a virtual source node;

[0088] S03: The virtual source node will periodically or eventually send a query message containing the identifier of the destination node of the message to the neighboring nodes;

[0089] S04: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and then jumps to step S07; otherwise, the neighboring node broadcasts routing request information and jumps to step S05.

[0090] S05: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighboring node through the destination node of the message, and jumps to step S06; otherwise, the neighboring node replies the routing error information to the virtual source node, and jumps to step S03.

[0091] S06: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S01; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S03.

[0092] S07: Message sent successfully.

[0093] In the specific implementation process, the routing error information includes the location information of the relay node at the point of interruption. The location information is generated through the following two location strategies.

[0094] Location Strategy 1: Gridded location information obtained with the assistance of satellite positioning systems;

[0095] Location strategy 2: Logical location information based on routing tables.

[0096] Combination Figure 2As shown, location strategy one generates location information through the following steps:

[0097] 1) A planar map of the network architecture region is pre-embedded, and the side length of the grid within the network architecture region is r;

[0098] 2) Nodes map their geographical location onto a planar map using the satellite positioning system, obtaining their location coordinates (x, y). i ,y i );

[0099] 3) Number the grids within the network architecture region, determine the reference node's position coordinates as (x0, y0) and the grid position number as (1, 1), where x0 ≤ x i y0≤y i ;

[0100] 4) Calculate the node (x) using the following formula. i ,y i The grid position (p) i ,q i ) as its location information;

[0101]

[0102]

[0103] In the formula: [] is the integer symbol, indicating that the smallest integer is selected.

[0104] Combination Figure 3 As shown, location strategy two refers to the virtual location information established by logical deduction based on the routing table, the node hop count in the neighbor table, and the number of neighbor nodes maintained in the ad hoc network routing protocol when a node in the network cannot obtain its own geographical location information through the satellite positioning system.

[0105] Combination Figure 4 As shown, if the message source node receives routing error information from the relay node at the point of interruption, then the following message sending strategy two is used:

[0106] S11: Determine whether the location information of the relay node is generated based on location strategy one: if yes, proceed to step S12; otherwise, proceed to step S13.

[0107] S12: Let the number of message replicas be n, then determine the number of nodes that the message source node can connect to be N, and determine whether there exists N>n-1: If yes, then select the outermost n nodes that are evenly distributed in all directions from the connectable nodes as virtual source nodes to store message replicas, and jump to step S15; otherwise, jump to step S13.

[0108] S13: Store a copy of the message in each relay node that sent the routing error information, making it a virtual source node, and then proceed to step S15;

[0109] S14: Send the message to the destination node, and then determine whether the message was sent successfully: if yes, proceed to step S19; otherwise, proceed to step S15.

[0110] S15: The virtual source node periodically or eventually sends a query message containing the destination node identifier to its neighboring nodes;

[0111] S16: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and jumps to step S19; otherwise, the neighboring node broadcasts routing request information, and jumps to step S17.

[0112] S17: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighbor node and jumps to step S18; otherwise, the neighbor node replies the routing error information to the virtual source node and jumps to step S15.

[0113] S18: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S14; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S15.

[0114] S19: Message sent successfully.

[0115] Combination Figure 5 As shown, if N>n-1, the virtual source node is determined through the following steps:

[0116] S121: Calculate the grid position (p0, q0) of the centroid of the internal grid using the following formula;

[0117]

[0118]

[0119] In the formula: (p i ,q i () indicates the grid position of a node within the topology;

[0120] S122: Calculate the vector X between each node in the topology and the centroid using the following formula. i ,(i=1,2…N);

[0121] X i =(pi -p0,q i -q0), (i = 1, 2…N);

[0122] S123: Let the number of message replicas be n. Then, the message source node retains one message replica and becomes a virtual source node. Then, with vector X1 as the axis, calculate the angle between the vector of each node in the network architecture region and vector X1.

[0123]

[0124] S124: Establish a set of reference angles Then the included angle The nodes within the (n-1) grid positions closest to an element in the reference angle set are designated as virtual source nodes. If multiple nodes exist within the same grid position, they are considered functionally equivalent, and any one of them is selected as the virtual source node.

[0125] This invention receives and forwards message copies through the DTN routing mechanism when reactive MANET routes are disconnected, thereby improving the reliability of message transmission. Furthermore, unlike existing reactive MANETs that directly switch routing strategies upon disconnection, this invention designs virtual source nodes to broadcast route solicitation messages to neighboring nodes. This allows the virtual source nodes to continuously seek connectable subtopologies, maximizing the utilization of connectable subtopologies. In other words, it fully explores connectable subtopologies within the MANET network, thereby improving the utilization rate of connectable topologies in the MANET and ultimately enhancing the practicality of message transmission.

[0126] Secondly, this invention incorporates node location information obtained through a satellite positioning system into the routing response and error information received by the reactive routing message source node. This location information is further processed to form a gridded location information structure. Furthermore, unlike the replica allocation method in the existing spray-wait protocol's spray phase, this invention designs a gridded virtual source node allocation algorithm based on different location strategies. Specifically, it selects the outermost nodes, evenly distributed in all directions, from the connectable nodes as virtual source nodes, enabling more accurate and effective determination of virtual source nodes and reducing network load caused by redundant information. This invention, through virtual source nodes, better seeks connectable sub-topologies, thereby maximizing the utilization of connectable sub-topologies. That is, it can fully explore the connectable sub-topologies in the MANET network, thus further improving the utilization rate of reactive MANET routing.

[0127] Finally, this invention provides two location strategies based on whether satellite system geographic location information can be obtained, which can better adapt to message transmission needs in different scenarios, thereby improving the stability and practicality of message transmission.

[0128] Example 2:

[0129] This embodiment discloses a readable storage medium.

[0130] A readable storage medium storing a computer management program, which, when executed by a processor, implements the steps of the converged reactive routing and DTN message transmission method of the present invention. The readable storage medium may be a device with readable storage capabilities, such as a USB flash drive or a computer.

[0131] 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 the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A message transmission method integrating reactive routing and DTN, characterized in that: When the message source node transmits a message to the message destination node: S1: First, use the reactive MANET routing protocol mechanism to broadcast routing request information in the network; S2: Receive routing response information from the message destination node or routing error information from the relay node at the point of communication link interruption through the message source node; if routing response information is received, transmit the message to the message source node. If a routing error message is received, the message copy is distributed to the relay node at the topology boundary of the message source node by using the DTN mechanism to make it a virtual source node, and the different communication connection conditions are distinguished. S3: Determine whether the message in transmission has been successfully delivered to the message destination node: if yes, the message transmission is successful; otherwise, store a copy of the message at the relay node where the communication link is interrupted, making it a virtual source node. S4: The virtual source node searches for the message destination node by broadcasting routing query information to its neighboring nodes. When it finds an opportunity to establish a connection with the message destination node, it jumps to step S2 until the message transmission is completed. The routing error message contains the location information of the relay node at the point of interruption. The location information is generated using the following two location strategies. Location Strategy 1: Gridded location information obtained with the assistance of satellite positioning systems; Location Strategy 2: Based on logical location information formed by the routing table; If the message source node receives a routing error message from the relay node at the point of interruption, then the following message sending strategy two is used: S11: Determine whether the location information of the relay node is generated based on location strategy one: if yes, proceed to step S12; otherwise, proceed to step S13. S12: Let the number of message replicas be n, then determine the number of nodes that the message source node can connect to be N, and determine whether there exists N>n-1: If so, select the outermost n nodes that are evenly distributed in all directions from the connectable nodes as virtual source nodes to store message replicas, and jump to step S15. Otherwise, proceed to step S13; S13: Store a copy of the message in each relay node that sent the routing error information, making it a virtual source node, and then proceed to step S15; S14: Send the message to the destination node, and then determine whether the message was sent successfully: if yes, proceed to step S19; otherwise, proceed to step S15. S15: The virtual source node periodically or eventually sends a query message containing the destination node identifier to its neighboring nodes; S16: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and jumps to step S19; otherwise, the neighboring node broadcasts routing request information, and jumps to step S17. S17: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighbor node and jumps to step S18; otherwise, the neighbor node replies the routing error information to the virtual source node and jumps to step S15. S18: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S14; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S15. S19: Message sent successfully; In step S12, if N>n-1, then based on different location strategies, a gridded virtual source node allocation algorithm is designed to select the outermost node that is evenly distributed along all directions from the connectable nodes as the virtual source node: S121: Calculate the grid position (p0, q0) of the centroid of the internal grid using the following formula; In the formula: (p i ,q i () indicates the grid position of a node within the topology; S122: Calculate the vector X between each node in the topology and the centroid using the following formula. i ,(i=1,2…N); X i =(p i -p0,q i -q0),(i=1,2…N); S123: Let the number of message replicas be n. Then, the message source node retains one message replica and becomes a virtual source node. Then, with vector X1 as the axis, calculate the angle between the vector of each node in the network architecture region and vector X1. S124: Establish a set of reference angles Then the included angle The nodes in the (n-1) grid positions that are closest to the elements in the reference angle set are used as virtual source nodes.

2. The message transmission method for integrating reactive routing and DTN as described in claim 1, characterized in that: If the message source node receives routing response information from the message destination node, then the following message sending strategy one is used: S01: Send the message to the destination node, and then determine whether the message was sent successfully: if yes, proceed to step S07; otherwise, proceed to step S02. S02: Store a copy of the message at the relay node at the point of interruption, making it a virtual source node; S03: The virtual source node will periodically or eventually send a query message containing the identifier of the destination node of the message to the neighboring nodes; S04: Determine whether the neighboring node is the destination node of the message: If yes, the neighboring node sends routing response information to the virtual source node and establishes a connection for the virtual source node to send messages, and then jumps to step S07; Otherwise, broadcast the routing request information through neighboring nodes and proceed to step S05; S05: Determine whether the destination node of the message has received the routing request information: if yes, then the destination node replies the routing response information to the neighboring node through the destination node of the message, and jumps to step S06; otherwise, the neighboring node replies the routing error information to the virtual source node, and jumps to step S03. S06: Determine whether the neighboring node has received the routing response information from the destination node of the message: if yes, the neighboring node receives the message copy and becomes the new virtual source node, and jumps to step S01; otherwise, the neighboring node replies to the virtual source node with routing error information, and jumps to step S03. S07: Message sent successfully.

3. The message transmission method for integrating reactive routing and DTN as described in claim 1, characterized in that: Location strategy one generates location information through the following steps: 1) A planar map of the network architecture region is pre-embedded, and the side length of the grid within the network architecture region is r; 2) Nodes map their geographical location onto a planar map using the satellite positioning system, obtaining their location coordinates (x, y). i ,y i ); 3) Number the grids within the network architecture region, determine the reference node's position coordinates as (x0, y0) and the grid position number as (1, 1), where x0 ≤ x i y0≤y i ; 4) Calculate the node (x) using the following formula. i ,y i The grid position (p) i ,q i ) as its location information; In the formula: [] is the integer symbol, indicating that the smallest integer is selected.

4. The message transmission method for integrating reactive routing and DTN as described in claim 1, characterized in that: Location strategy two refers to the virtual location information established by logical deduction based on the routing table, the node hop count in the neighbor table, and the number of neighbor nodes maintained in the ad hoc network routing protocol when a node in the network cannot obtain its own geographical location information through the satellite positioning system.

5. The message transmission method for integrating reactive routing and DTN as described in claim 1, characterized in that: In step S124, if there are multiple nodes in the same grid location, the functions of each node are considered to be equivalent, and any node is selected as the virtual source node.

6. The message transmission method for integrating reactive routing and DTN as described in claim 1, characterized in that: When a message source node broadcasts a routing request, there is a broadcast time threshold. If the message source node does not receive any message after the broadcast time threshold is reached, the message source node broadcasts a copy of the message to neighboring nodes until the message is delivered or the message's lifespan expires.

7. A readable storage medium, characterized in that, It stores a computer management program, which, when executed by a processor, implements the steps of the converged reactive routing and DTN message transmission method as described in any one of claims 1-6.

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