A method for optimizing geographic routing based on two-hop peripheral forwarding

Abstract

The application belongs to the field of wireless communication, and discloses a kind of geographical routing optimization method based on two-hop peripheral forwarding, comprising: step 1, construct local neighbor information base, step 2, calculate the forwarding priority value of current node;Step 3, the reachability of current node to neighbor node is predicted and evaluated;Step 4, if there is candidate neighbor node in one-hop candidate neighbor node set, then select the one-hop neighbor node with the minimum forwarding priority of neighbor node as the next hop node, and complete data forwarding;Step 5, if one-hop candidate neighbor node set is empty, then trigger two-hop forwarding mechanism;Step 6, after completing data forwarding, if the current node is not the destination node, then the new forwarding node continues to execute step 1-step 5, if the current node is the target node, then the forwarding process of data packet is ended.The application improves the robustness and forwarding efficiency in complex dynamic environment while maintaining the advantage of stateless forwarding of GNSR.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of wireless communication, and in particular relates to a geographic routing optimization method based on two-hop peripheral forwarding. BACKGROUND

[0002] With the continuous development of dynamic topology network environments such as tactical communication networks and Internet of vehicles, traditional routing protocols based on link state or topology table driving have obvious limitations in frequently changing scenarios. In order to adapt to such high-dynamic and infrastructure-free network environments, a geographic-based stateless routing protocol (GNSR, Geographic-based Network Stateless Routing) is proposed. The GNSR method relies on the geographic position, motion direction and speed of nodes and other information to achieve efficient data forwarding without relying on global topology and routing table, and has good topology adaptability and routing flexibility.

[0003] In GNSR, nodes usually use hop-by-hop forwarding mechanism to send data packets to the neighbor node closest to the destination node in the instantaneous geographic position. However, in actual deployment, due to node mobility, channel fluctuation or spatial obstacles, the phenomenon of "local forwarding stagnation" often occurs, that is, the current node cannot find a next hop node that is still better than itself at the next moment, resulting in interruption of the forwarding process. In order to solve such problems, a two-hop peripheral forwarding mechanism is introduced in GNSR, which selects a better forwarding path by extending to the two-hop neighbor range, trying to jump out of the local optimal trap.

[0004] However, the existing two-hop peripheral forwarding method is mostly based on simple distance or right-hand rule judgment, which has the following problems: only relying on the static position information of neighbor nodes, without considering dynamic factors such as speed and direction, it is difficult to adapt to high-speed mobile scenarios; nodes lack perception of neighbor density, link stability and other factors, resulting in insufficient forwarding selection accuracy; the current method lacks effective global evaluation index when selecting two hops, which is easy to fall into new local optimum, affecting the overall routing success rate and stability. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a geographic routing optimization method based on two-hop peripheral forwarding, which further optimizes the two-hop peripheral forwarding mechanism on the basis of GNSR, introduces the forwarding priority value of nodes, and comprehensively considers factors such as position information, speed vector and neighbor density, while maintaining the stateless forwarding advantage of GNSR, improves the robustness and forwarding efficiency in complex dynamic environment.

[0006] In order to achieve the above purpose, the present application is realized by the following technical scheme:

[0007] This application presents a geographical routing optimization method based on two-hop surrounding forwarding. The geographical routing optimization method specifically includes the following steps:

[0008] Step 1: Build and maintain a local neighbor information database: The current node periodically broadcasts the current node status announcement message. At the same time, the current node listens for and receives the status announcement messages of neighboring nodes, and builds and maintains a local neighbor information database based on the current node status announcement message and the neighboring node status announcement messages.

[0009] Step 2: By reading the status announcement messages of neighboring nodes stored in the local neighbor information database constructed in Step 1, and combining them with the current node's status announcement message (i.e., geographical location information, velocity vector, acceleration vector, remaining energy level, local clock synchronization information, and the number of neighboring nodes), calculate the forwarding priority value of the current node. This measures the applicability of the current node in the forwarding process;

[0010] Step 3: The current node reads cached information from the constructed local neighbor information database to obtain the status announcement messages of each neighbor node. Combining the status announcement messages of each neighbor node, the current node predicts and evaluates the reachability of the neighbor nodes within a prediction period T, where T is the prediction time window, usually 1–3 seconds, which can be adaptively adjusted according to the node's movement speed and the dynamic characteristics of the network scenario. If a neighbor node is still within the communication coverage area within the prediction period, the neighbor node is retained, and its forwarding priority value is calculated. If the prediction result indicates that a neighboring node is about to leave the coverage area, then that neighboring node is removed from all neighboring nodes, and only those that meet the requirements are retained. < Given candidate neighbor nodes, construct a one-hop candidate neighbor node set;

[0011] Step 4: If there are candidate neighbor nodes in the one-hop candidate neighbor node set, then select the forwarding priority value of the neighbor node. The smallest first-hop neighbor node is used as the next-hop node and the data forwarding is completed. After the forwarding is completed, the candidate neighbor node is updated to the new current node, and then steps 1-4 are repeated.

[0012] Step 5: If the set of candidate neighbor nodes for one hop is empty, then the two-hop forwarding mechanism is triggered;

[0013] Step 6: After data forwarding is completed, if the current node is not the destination node, the new forwarding node continues to execute steps 1-5. If the current node is the destination node, the data packet forwarding process ends.

[0014] The further improvement of the application is that the current node state notification message and the state notification message of the neighbor node in step 1 respectively comprise geographical position information, a speed vector, an acceleration vector, a residual energy level, local clock synchronization information of the node.

[0015] The further improvement of the application is that in step 2, the forwarding priority value of the current node is calculated according to the following formula: The calculation formula is as follows:

[0016]

[0017]

[0018] Wherein, is the Euclidean distance between the current node and the destination node, is the instantaneous speed of the node ; is the position offset of the current node in the prediction time window T, is the acceleration vector of the node, is the link stability factor, is the neighbor density factor of the current node, and the larger the value is, the better the local area connectivity of the node is; is the speed vector of the node at the current position, is the dynamic adjustment coefficient.

[0019] The further improvement of the application is that in step 3, the forwarding priority value of the neighbor node is calculated according to the following formula: The calculation formula is as follows:

[0020]

[0021]

[0022] Wherein, is the Euclidean distance between the neighbor node and the destination node, is the speed of the neighbor node ; is the position offset of the neighbor node in the prediction time window, is the link stability factor of the neighbor node , is the neighbor density factor of the neighbor node, is the speed vector of the neighbor node . ​​

[0023] The further improvement of the present application is that in step 5, the two-hop forwarding mechanism is specifically:

[0024] Step 5.1, by analyzing the joint information of the one-hop neighbor node of the current node and the two-hop neighbor node of the current node, the comprehensive FPV of the two-hop neighbor node of the current node is calculated, and the calculation formula is:

[0025]

[0026] Wherein: is the FPV value of the two-hop neighbor node Z itself, which is calculated using the same formula as the one-hop neighbor; represents the link quality between the one-hop neighbor node M and the two-hop neighbor node Z, is the weight coefficient of the link quality factor, which is used to dynamically adjust the influence of the link quality in the comprehensive FPV;

[0027] Step 5.2, select the two-hop neighbor node Z with the minimum FPV, and determine the one-hop relay node M that can reach the two-hop neighbor node Z;

[0028] Step 5.3, first forward the data to the relay node M, and then forward the data to the two-hop neighbor node Z by the relay node M.

[0029] The beneficial effects of the present application are:

[0030] The present application can continue to effectively forward data when a routing hole appears by introducing a multi-dimensional forwarding priority value (FPV) calculation based on motion prediction and link quality when a routing hole appears, thereby effectively avoiding routing interruption and improving the reliability of data transmission.

[0031] The present application can more accurately evaluate the priority of the node in the network by dynamically calculating the forwarding priority value of the node by comprehensively considering the position, speed, neighbor node density and other factors of the node. Compared with the traditional algorithm, the present application shows stronger adaptability in complex network topology changes, and significantly improves the routing success rate.

[0032] The present application reduces unnecessary control information exchange by optimizing the algorithm design. The node only needs to periodically send and receive messages and calculate the forwarding value based on local information, so as to realize efficient data forwarding, thereby reducing the control information overhead in the network and improving the utilization rate of network resources.

[0033] Compared with the prior art, the two-hop peripheral forwarding mechanism of the present application has the defects that the neighbor node judgment, node forwarding value calculation and communication range out-of-bounds judgment are added when selecting the next hop node. The position of the neighbor node can be judged within the transmission range in a short time. Specifically, the nodes that move out of the communication transmission range at the next moment are eliminated through the position and angle relationship between the neighbor node and the destination node, and the density of the neighbor node is considered to calculate the forwarding value of the neighbor node, and the neighbor node with the smallest forwarding value is selected to forward data, thereby ensuring the reliability of data forwarding, effectively controlling the routing overhead and improving the data forwarding efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flowchart of the two-hop peripheral forwarding mechanism of the present application.

[0035] Figure 2 is a flowchart of the two-hop peripheral forwarding mechanism of the present application.

[0036] Figure 3 is a flowchart of the two-hop peripheral forwarding mechanism of the present application.

[0037] Figure 4 The relationship between the end-to-end delay of various routing algorithms and the node moving speed under different node density conditions is shown.

[0038] Figure 5 The trend of the packet delivery success rate of various routing algorithms with the node moving speed under different node density conditions is compared. DETAILED DESCRIPTION

[0039] The embodiments of the present application will be described below with reference to the drawings. Many practical details will be described in the following description for the purpose of clear illustration. However, it should be understood that these practical details are not used to limit the present application. That is, in some embodiments of the present application, these practical details are unnecessary. In addition, for the purpose of simplifying the drawings, some conventional structures and components will be shown in a simple schematic manner in the drawings.

[0040] As shown in Figures 1-3 , the present application is a geographic routing optimization method based on two-hop peripheral forwarding, which specifically includes the following steps:

[0041] Step 1, constructing and maintaining a local neighbor information base: the current node periodically broadcasts a current node state announcement message, meanwhile, the current node listens and accepts the state announcement message of the neighbor node, and constructs and maintains a local neighbor information base according to the current node state announcement message and the state announcement message of the neighbor node; the local neighbor information base includes the neighbor nodes within one-hop and two-hop communication range and the dynamic state information of the neighbor nodes; the process is used to master the local network environment and node state in real time. The current node state announcement message and the state announcement message of the neighbor node in step 1 respectively include the geographic position information, the speed vector, the acceleration vector, the residual energy level, the local clock synchronization information and the like of the node;

[0042] Step 2, calculating the forwarding priority value of the current node by reading the state announcement message of the neighbor node stored in the local neighbor information base constructed in step 1, and combining the current node state announcement message, i.e. the geographic position information, the speed vector, the acceleration vector, the residual energy level, the local clock synchronization information and the number of neighbor nodes, as multi-dimensional factors. , to measure the applicability of the current node in the forwarding process.

[0043] The forwarding priority value of the current node The calculation formula is:

[0044]

[0045]

[0046] Wherein, is the Euclidean distance between the current node and the destination node , represents the instantaneous speed of the node , i.e. the speed vector; represents the position offset of the current node within the prediction time window T, i.e. the geographic position information, is the acceleration vector of the node, i.e. the acceleration vector, represents the link stability factor, which is used to describe the average duration or relative speed distribution of the communication connection between the current node and the neighbor node; represents the neighbor density factor of the current node, and the larger the value is, the better the local area connectivity of the node is; represents the speed vector of the node i at the current position, is a dynamic adjustment coefficient, and the local clock synchronization information and the prediction time window T.

[0047] Step 3: The current node reads cached information from the constructed local neighbor information database to obtain the status announcement messages of each neighbor node. Combining the status announcement messages of each neighbor node, the current node predicts and evaluates the reachability of the neighbor nodes within a prediction period T, where T is the prediction time window, usually 1–3 seconds, which can be adaptively adjusted according to the node's movement speed and the dynamic characteristics of the network scenario. If a neighbor node is still within the communication coverage area within the prediction period, the neighbor node is retained, and its forwarding priority value is calculated. If the prediction result indicates that a neighboring node is about to leave the coverage area, then that neighboring node is removed from all neighboring nodes, and only those that meet the requirements are retained. < Given candidate neighbor nodes, construct a one-hop candidate neighbor node set;

[0048] Forwarding priority of neighboring nodes The calculation formula is:

[0049]

[0050]

[0051] in, Representing neighboring nodes With the target node The Euclidean distance between them Representing neighboring nodes The magnitude of the speed; Representing neighboring nodes Position offset within the prediction time window Representing neighboring nodes Link stability factor, The neighbor density factor represents the neighboring node. Representing neighboring nodes The velocity vector.

[0052] Step 4: If there are candidate neighbor nodes in the one-hop candidate neighbor node set, then select the forwarding priority value of the neighbor node. The smallest first-hop neighbor node is used as the next-hop node and the data forwarding is completed. After the forwarding is completed, the candidate neighbor node is updated to the new current node, and then steps 1-4 are repeated.

[0053] Step 5: If the set of one-hop candidate neighbor nodes is empty, the two-hop forwarding mechanism is triggered. The two-hop forwarding mechanism is as follows:

[0054] Step 5.1: By analyzing the joint information of the current node's one-hop neighbors and two-hop neighbors, calculate the combined FPV of the current node's two-hop neighbors. The calculation formula is as follows:

[0055]

[0056] wherein: is the FPV value of the two-hop neighbor node Z itself, calculated using the same formula as the one-hop neighbor; represents the link quality between the one-hop neighbor node M and the two-hop neighbor node Z, is the weight coefficient of the link quality factor, used to dynamically adjust the influence of the link quality in the comprehensive FPV;

[0057] Step 5.2, select the two-hop neighbor node Z with the minimum FPV, and determine the one-hop relay node M capable of reaching the two-hop neighbor node Z;

[0058] Step 5.3, first forward the data to the relay node M, and then forward the data from the relay node M to the two-hop neighbor node Z.

[0059] Step 6, after completing the data forwarding, if the current node is not the destination node, the new forwarding node continues to perform steps 1-5, and if the current node is the target node, the data packet forwarding process ends.

[0060] Compared with the traditional forwarding scheme, the present application not only focuses on the distance attribute, but also introduces the forwarding priority value calculated according to the own attribute information before forwarding If the next hop node is empty, it means that the current node has no suitable neighbor node for direct forwarding of data in the network.

[0061] Figure 4 The figure shows the relationship between the end-to-end delay of various routing algorithms and the node moving speed under different node density conditions. Figure 4 The multiple curves in the figure respectively represent the performance of different node densities such as low, medium and high density or different algorithms under the corresponding density. The present application can maintain a low transmission delay in a complex scenario of high moving speed and high node density, which is superior to the traditional GPSR algorithm. The effectiveness of the forwarding priority value calculation and the two-hop forwarding mechanism in reducing the data transmission waiting time.

[0062] Figure 5 The figure compares the trend of the packet delivery success rate of various routing algorithms with the node moving speed under different node densities. The present application can maintain a high routing success rate in a high-speed node and high-density network environment, and its performance is superior to other comparative algorithms. Through the strategy of integrating multi-dimensional state information for reachability prediction and intelligent routing selection, the present application can effectively overcome the challenges brought by the rapid change of network topology, and significantly improve the communication reliability.

[0063] In summary, compared with the traditional two-hop peripheral forwarding algorithm, the application effectively improves the routing hole problem existing in the wireless communication network and the limitation of the traditional algorithm. By comprehensively considering the multi-dimensional information such as the position, speed and neighbor node density of the node, the node forwarding value is dynamically calculated, and the path selection is combined with the global information of the two-hop neighbor node, so that the routing hole problem is effectively solved, and the complex network topology change is effectively adapted.

[0064] The above merely describes the embodiments of the present application and is not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A geographical routing optimization method based on two-hop surrounding forwarding, characterized in that: The geographical routing optimization method specifically includes the following steps: Step 1: Build and maintain a local neighbor information database: The current node periodically broadcasts the current node status announcement message. At the same time, the current node listens for and receives the status announcement messages of neighboring nodes, and builds and maintains a local neighbor information database based on the current node status announcement message and the neighboring node status announcement messages. Step 2: By reading the status announcement messages of neighboring nodes stored in the local neighbor information database constructed in Step 1, and combining the current node's status announcement message and the number of neighboring nodes, calculate the forwarding priority value of the current node. This measures the applicability of the current node in the forwarding process; Step 3: The current node reads cached information from the constructed local neighbor information database to obtain the status announcement messages of each neighbor node. Combining the status announcement messages of each neighbor node, the current node predicts and evaluates the reachability of the neighbor nodes within a prediction period T, where T is the prediction time window. If a neighbor node is still within the communication coverage area within the prediction period, the neighbor node is retained, and the forwarding priority value of the neighbor node is calculated. If the prediction result indicates that a neighboring node is about to leave the communication coverage area, then that neighboring node is removed from all neighboring nodes, and only those that meet the requirements are retained. < Given candidate neighbor nodes, construct a one-hop candidate neighbor node set; Step 4: If there are candidate neighbor nodes in the one-hop candidate neighbor node set, then select the forwarding priority value of the neighbor node. The smallest first-hop neighbor node is used as the next-hop node and the data forwarding is completed. After the forwarding is completed, the candidate neighbor node is updated to the new current node, and then steps 1-4 are repeated. Step 5: If the set of candidate neighbor nodes for one hop is empty, then the two-hop forwarding mechanism is triggered; Step 6: After data forwarding is completed, if the current node is not the destination node, the new forwarding node continues to execute steps 1-5. If the current node is the destination node, the data packet forwarding process ends. The two-hop forwarding mechanism is as follows: Step 5.1: By analyzing the joint information of the current node's one-hop neighbors and two-hop neighbors, calculate the combined FPV of the current node's two-hop neighbors. The calculation formula is as follows: ， in: The FPV value of the two-hop neighbor node Z itself. Let M be the link quality between a one-hop neighbor node M and a two-hop neighbor node Z. This is the weighting coefficient for the link quality factor, used to dynamically adjust the impact of link quality on the overall FPV; Step 5.2: Select the two-hop neighbor node Z with the smallest FPV, and determine the one-hop relay node M that can reach the two-hop neighbor node Z; Step 5.3: First forward the data to relay node M, and then relay node M forwards it to the two-hop neighbor node Z.

2. The geographical routing optimization method based on two-hop surrounding forwarding according to claim 1, characterized in that: The current node status announcement message and the neighbor node status announcement message in step 1 mainly include the node's geographical location information, velocity vector, acceleration vector, and local clock synchronization information.

3. The geographical routing optimization method based on two-hop surrounding forwarding according to claim 1, characterized in that: In step 2, the forwarding priority value of the current node. The calculation formula is: ， ， in, For the current node to the destination node The Euclidean distance between them For nodes The magnitude of the instantaneous velocity; This indicates the current node within the prediction time window T. Position offset Let be the acceleration vector of the node. For link stability factor, The neighbor density factor of the current node. For nodes The velocity vector at the current position, This is the dynamic adjustment coefficient.

4. The geographical routing optimization method based on two-hop surrounding forwarding according to claim 1, characterized in that: In step 3, the forwarding priority value of neighboring nodes The calculation formula is: ， ， in, Neighboring nodes With the target node The Euclidean distance between them Neighboring nodes The magnitude of the speed; Neighboring nodes Position offset within the prediction time window Neighboring nodes Link stability factor, Neighboring nodes Neighbor density factor Neighboring nodes The velocity vector.

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