Improved optimized link state routing protocol for unmanned aerial vehicle group under hybrid communication architecture

Abstract

The invention discloses an improved optimization link state routing protocol for an unmanned aerial vehicle cluster under a hybrid communication architecture, the unmanned aerial vehicle cluster comprises a plurality of unmanned aerial vehicle nodes, and each node is simultaneously equipped with an omnidirectional RF transceiver antenna and a directional FSO transceiver; in the routing process, the RF link is used for controlling stable distribution of messages, and the FSO link is used for high-speed transmission of service data; a multi-index multi-point relay node comprehensive selection algorithm is designed, and message propagation is optimized and controlled by combining node coverage, average two-hop link stability and relay load indexes; establishing a real-time link quality prediction mechanism based on unscented Kalman filtering, and generating a routing path of stability perception; and a routing compression method adaptive to heterogeneous link propagation characteristics is developed, and redundant hops are eliminated. Through the improved OLSR protocol, the problems of topological response lagging, insufficient link stability and low heterogeneous network efficiency of a traditional routing protocol under a hybrid communication architecture are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of UAV communication technology, and specifically relates to an improved optimized link state routing protocol for UAV swarms under a hybrid communication architecture, which is particularly suitable for achieving efficient and reliable data transmission using free-space optical and radio frequency links in highly dynamic environments. Background Art

[0002] With the rapid development of drone technology, drone swarms are being used more and more widely in military and civilian fields. Drone swarms collaborate to complete tasks through self-organizing networks, and have advantages such as high flexibility and strong adaptability. However, existing drone swarm communications mainly rely on traditional radio frequency technology, which has the following limitations: Link instability: In highly dynamic environments, the rapid movement of drones causes frequent changes in network topology, which traditional routing protocols find difficult to adapt to, resulting in frequent link interruptions and impacting communication reliability. Limited bandwidth: Radio frequency communications are limited by spectrum resources and cannot meet the high bandwidth requirements of large-scale drone swarms, especially in scenarios such as transmitting high-definition video and real-time data. Insufficient security: Radio frequency communications are susceptible to electromagnetic interference and eavesdropping, making it difficult to ensure the confidentiality and integrity of data transmission. Excessive latency: Multi-hop routing increases end-to-end latency, impacting real-time applications such as emergency communications and real-time monitoring.

[0003] In recent years, free-space optical communications (FSOCs), with their high bandwidth and high security, have emerged as a potential solution to these challenges. However, FSCO faces challenges in complex environments, such as atmospheric turbulence and pointing errors, and requires precise node alignment and high stability. Therefore, single-source FSCO or RF communications are insufficient to meet the communication needs of drone swarms for diverse missions.

[0004] Existing research attempts to combine the advantages of both optical and optical networks through hybrid optical architectures. However, these hybrid architectures often rely on simple link selection strategies, failing to fully leverage the high bandwidth of optical communications and the stability of radio frequency. For example, some studies use optical communications for high-speed backbone networks and radio frequency for redundancy or extended coverage. However, this architecture fails to dynamically adapt to changes in information type and environment, resulting in low network resource utilization and inefficient communication.

[0005] In summary, existing drone cluster communication technology has problems such as link instability, limited bandwidth, insufficient security and excessive latency in highly dynamic and complex environments. There is an urgent need for a hybrid communication routing method that can dynamically adapt to environmental changes and fully utilize the advantages of optical communication and radio frequency. Summary of the Invention

[0006] Purpose of the invention: In response to the deficiencies in the existing technology, the present invention proposes an improved optimized link state routing protocol for drone swarms under a hybrid communication architecture to solve the problems of link instability, high latency and excessive control overhead in traditional routing protocols in existing drone swarm communication networks under highly dynamic topology changes.

[0007] Technical Solution: The present invention discloses an improved optimized link state routing protocol for drone swarms under a hybrid communication architecture. The drone swarm includes multiple drone nodes, each equipped with both an omnidirectional RF transceiver antenna and a directional FSO transceiver. During routing, the RF link is used for stable distribution of control messages, and the FSO link is used for high-speed transmission of service data. The protocol includes the following steps:

[0008] S1, the drone node in the network obtains its own three-dimensional spatial position information in real time through GPS, and predicts the location of the next Hello message sending time node through unscented Kalman filtering;

[0009] S2: Each node encapsulates its current location information, predicted location information, the MSS length of its own MPR selection set, and the addresses of various neighbor nodes into a normal Hello message. The link stability value LS between the neighbor nodes is appended to the address of the neighbor node with the one-hop symmetric neighbor type. This improved Hello message is broadcast via the omnidirectional RF antenna.

[0010] S3: When a node receives a Hello message, it stores it locally and checks whether the distance to the source node exceeds one hop of optical link distance. If the message is received for the first time and the distance is within one hop, it continues to forward it.

[0011] In S4, the node implements a three-way handshake through Hello messages to identify one-hop symmetric neighbors within the omnidirectional range and one-hop symmetric neighbors within the directional range;

[0012] S5, based on the omnidirectional neighbor information, comprehensively considers the node coverage index, the average two-hop omnidirectional link stability and the MPR selection set length index by establishing a weighted calculation formula, and selects the optimal MPR node set that can cover all two-hop nodes according to the ranking of the comprehensive measurement indicators.

[0013] S6, the node selected as the MPR calculates the directional link stability value with all nodes in the local MPR selection set, modifies the TC message format, appends the directional link stability value to the IP address of the included nodes, and broadcasts it through the omnidirectional RF antenna;

[0014] S7: After receiving the TC message, if the node is the first to receive it and it is the source MPR node, it forwards it through the omnidirectional RF antenna, otherwise it does not forward it;

[0015] S8: The node obtains the network topology and link stability values ​​based on the TC message and stores them in the local topology table.

[0016] S9, the node converts the link stability value into the link cost value in the topology table through logarithmic operation, and uses the Dijkstra algorithm to calculate the entire network route and establish a routing table;

[0017] S10: When a node encounters a demand for sending a business message, it forwards the message entirely through the FSO link according to the pre-built routing table.

[0018] Furthermore, the improved Hello message format includes the current location, predicted location, MPR selection set length value of the source node, the type and address of the neighbor node, and the omnidirectional link stability value of the one-hop symmetric neighbor; the omnidirectional link stability value of the neighbor node M of the source node S is calculated according to the following formula:

[0019]

[0020] Among them, d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum movement speed of node M; α is the angle between v and d; k v 、k t 、k d It is a constant parameter and should be adjusted according to actual conditions.

[0021] Furthermore, the implementation process of step S5 is as follows:

[0022] The node coverage index that measures the coverage range of the neighbor nodes M of the source node S is calculated according to the following formula:

[0023]

[0024] The omnidirectional average two-hop link stability value of the neighbor node M of the source node S is calculated according to the following formula:

[0025]

[0026] The MPR selection set length index of the neighbor node M of the source node S is calculated according to the following formula:

[0027]

[0028] The comprehensive quality index of the neighbor node M of the source node S is calculated according to the following formula:

[0029] CLQ=a*ALS+b*MSSLI+c*CDI

[0030] Among them, len() is the length function of the set, N1(S) is the one-hop symmetric neighbor set of the source node S; N2(S,M) is the two-hop neighbor set connected to the source node S through the one-hop neighbor M; len(MSS M ) is the number of nodes selected as MPR nodes, which is provided by the Hello message of node M; a, b, and c are the weights of indicators ALS, MSSLI, and CDI, respectively, satisfying a+b+c=1;

[0031] When selecting MPR nodes, nodes that are connected to some two-hop nodes by only one relay node are first selected as MPR nodes. Then, the CLQ value of each node is calculated. If multiple nodes have the same CLQ, the values ​​of ALS, MSSLI, and CDI are compared in turn, and the nodes are added to the MPR node set from high to low until all two-hop nodes are covered.

[0032] Furthermore, the modified TC message format includes the addresses and link stability values ​​of all nodes in the MPR selection set.

[0033] Furthermore, the directional link stability value in step S6 is:

[0034]

[0035] Among them, d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum movement speed of node M; α is the angle between v and d; k ⊥ 、k t 、k / / is a constant parameter.

[0036] Furthermore, the link cost value in step S9 is:

[0037] cost=-ln(LS d )

[0038] Among them, LS d is the directional link stability value mentioned above, and cost is the link cost value in the topology table.

[0039] A device according to the present invention includes a memory and a processor, wherein:

[0040] a memory for storing computer programs capable of running on the processor;

[0041] The processor is used to execute the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described above when running the computer program.

[0042] The present invention provides a storage medium having a computer program stored thereon, which, when executed by at least one processor, implements the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described above.

[0043] Beneficial effects: Compared with the existing technology, the beneficial effects of the present invention are: the present invention aims to solve the problems of link instability, excessive delay and excessive control overhead of traditional routing protocols in existing drone swarm communication networks under highly dynamic topology change environments by establishing an improved optimized link state routing protocol for drone swarms under a hybrid communication architecture; the present invention provides a reliable hybrid communication infrastructure in highly dynamic drone swarm networks to ensure the quality of service; experimental results show that compared with the traditional optimized link state routing (Optimize Link State Routing, OLSR) protocol, the present invention significantly improves the data packet transmission rate under different communication architectures, reduces end-to-end delay and control cost, and is suitable for the complex environment of large-scale drone swarm operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A flowchart of the process of establishing an improved routing protocol under the hybrid architecture proposed by the present invention;

[0045] Figure 2 The format diagram of the modified Hello message provided by the present invention;

[0046] Figure 3 This is a diagram of the format of the improved TC message provided by the present invention. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below with reference to the accompanying drawings.

[0048] The present invention proposes an improved optimized link state routing protocol for drone swarms under a hybrid communication architecture, aiming to solve the problems of unstable links, high latency, and inability to fully utilize the advantages of free space optical communication (FSO) and radio frequency (RF) communication in traditional routing protocols in existing drone swarm communications in highly dynamic environments. The present invention uses a multi-standard multi-point relay (MPR) selection algorithm, a stability-aware routing mechanism, and a routing compression method to ensure the service quality of confidential operation information transmission using the high bandwidth and high security of FSO, while using the stability of RF to ensure the reliable transmission of control messages, thereby maintaining the stability of the network topology in a diverse environment. Figure 1 As shown, the specific steps include:

[0049] S1, the drone node in the network obtains its own three-dimensional spatial position information in real time through the GPS device it carries, and predicts its node position at the next Hello message sending time through the Unscented Kalman Filter (UKF) algorithm.

[0050] In S2, each node encapsulates its current location information and predicted location information into a Hello message, and also includes the length of its MPR selection set (MSS), the type and address of each neighbor node, and the omnidirectional link stability value (LSL) between it and the neighbor node after the IP address if the type is a symmetric neighbor. o ), and finally get Figure 2 The modified Hello message shown is broadcast outward through the omnidirectional RF antenna.

[0051] The omnidirectional link stability value between the source node S and the symmetric neighbor node M is calculated according to the following formula:

[0052]

[0053] where d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum movement speed of node M; α is the angle between v and d; k v 、k t 、k d It is a constant parameter and can be adjusted according to actual conditions.

[0054] In step S3, when a node receives a Hello message via its RF antenna, it checks whether the distance to the source node exceeds one optical link hop. If the message is received for the first time and the distance is within one hop, it continues forwarding the message. Otherwise, it stops forwarding the message and stores the data in the Hello message in a local table.

[0055] In step S4, the nodes exchange Hello messages and implement a three-way handshake based on the neighbor information in the Hello messages. They identify one-hop symmetric neighbors within the omnidirectional range and one-hop symmetric neighbors within the directional range outside the omnidirectional range, and store the relevant information in the local neighbor information table.

[0056] In step S5, based on the locally stored omnidirectional symmetric neighbor information, the node coverage index (CDI), average two-hop omnidirectional link stability (ALS), and MPR selection set length index (MSSLI) are comprehensively considered to calculate the weighted comprehensive quality index (CLQ) value of each omnidirectional symmetric neighbor node, and then select the MPR node set from them. When selecting MPR nodes, nodes that are connected to certain two-hop nodes by only one relay node are first selected as MPR nodes. The CLQ value of each node is then calculated. If multiple nodes have the same CLQ, the ALS, MSSLI, and CDI values ​​are compared in sequence, and nodes are added to the MPR node set from highest to lowest until all two-hop nodes are covered and selection stops.

[0057] The node coverage index that measures the coverage range of the neighbor nodes M of the source node S is calculated according to the following formula:

[0058]

[0059] The omnidirectional average two-hop link stability value of the neighbor node M of the source node S is calculated according to the following formula:

[0060]

[0061] The MPR selection set length index of the neighbor node M of the source node S is calculated according to the following formula:

[0062]

[0063] The comprehensive quality index of the neighbor node M of the source node S is calculated according to the following formula:

[0064] CLQ=a*ALS+b*MSSLI+c*CDI

[0065] Among them, len() is the length function of the set, N1(S) is the one-hop symmetric neighbor set of the source node S; N2(S,M) is the two-hop neighbor set connected to the source node S through the one-hop neighbor M; len(MSS M) is the number of nodes selected as MPR nodes, which is provided by the Hello message of node M; a, b, and c are the weights of indicators ALS, MSSLI, and CDI, respectively, which are in the range of 0 to 1 and satisfy a+b+c=1.

[0066] S6, the node selected as MPR calculates the directional link stability value (LS d ), and modify the TC message format, append the directional link stability value to the node IP address, and broadcast it through the omnidirectional RF antenna. Figure 3 The improved TC message format shown includes the addresses of all nodes in the MPR selection set and the directional link stability value.

[0067] The directional link stability value is:

[0068]

[0069] Among them, d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum speed of the UAV node; α is the angle between v and d; k ⊥ 、k t 、k / / It is a constant parameter and can be adjusted according to actual conditions.

[0070] In step S7, after a node receives a Topology Control (TC) message through the RF antenna, if it is the first time receiving the message and it is an MPR node that is the source node, it forwards the message through the omnidirectional RF antenna. Otherwise, it does not forward the message and finally stores the data in the TC message locally.

[0071] In S8, the node obtains the directional stability value of the entire network topology and each link in the topology based on the information in the TC message, and stores it in the local topology table for subsequent calculations. At the same time, it also directly stores the directional link stability value between the node and the one-hop symmetric neighbor within the directional range outside its own omnidirectional range in the local topology table to achieve appropriate routing compression.

[0072] In step S9, the node converts the stability values ​​of each directional link in the local topology table into link cost values ​​in the topology table by taking the logarithm. This converts the link stability requirements of the multiplication into the summation used by the Dijkstra algorithm. Finally, each node calculates the full network route using the Dijkstra algorithm and establishes its own full network routing table.

[0073] The calculation method of the above link cost value is:

[0074] cost=-ln(LS d ).

[0075] Among them, LS d is the directional link stability value mentioned above, and cost is the link cost value in the topology table.

[0076] In step S10, the node continuously updates its routing table by receiving and sending Hello messages and TC messages at regular intervals. When a node needs to send a service message or receives a service message that needs to be forwarded, it queries the pre-built routing table and forwards it to the next hop node via the laser transmitter.

[0077] The present invention also proposes a device, including a memory and a processor, wherein: the memory is used to store a computer program that can be run on the processor; the processor is used to execute the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described above when running the computer program.

[0078] The present invention also provides a storage medium having a computer program stored thereon, and when the computer program is executed by at least one processor, the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described above are implemented.

[0079] Compared with the existing technology, the present invention significantly improves the data transmission rate, reduces the end-to-end delay and control cost in a highly dynamic environment, and provides reliable communication support for large-scale drone cluster operations.

[0080] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An improved optimized link state routing protocol for drone swarms under a hybrid communication architecture, characterized by: The drone cluster includes multiple drone nodes, each of which is equipped with an omnidirectional RF transceiver antenna and a directional FSO transceiver. During the routing process, the RF link is used to stably distribute control messages, and the FSO link is used for high-speed transmission of service data. The protocol includes the following steps: S1, the drone node in the network obtains its own three-dimensional spatial position information in real time through GPS, and predicts the position of the next Hello message sending time node through unscented Kalman filtering; S2: Each node encapsulates its current location information, predicted location information, the MSS length of its own MPR selection set, and the addresses of various neighbor nodes into a normal Hello message. The link stability value LS between the neighbor nodes is appended to the address of the neighbor node with the one-hop symmetric neighbor type. This improved Hello message is broadcast via the omnidirectional RF antenna. S3: When a node receives a Hello message, it stores it locally and checks whether the distance to the source node exceeds one hop of optical link distance. If the message is received for the first time and the distance is within one hop, it continues to forward it. In S4, the node implements a three-way handshake through Hello messages to identify one-hop symmetric neighbors within the omnidirectional range and one-hop symmetric neighbors within the directional range; S5, based on the omnidirectional neighbor information, comprehensively considers the node coverage index, the average two-hop omnidirectional link stability and the MPR selection set length index by establishing a weighted calculation formula, and selects the optimal MPR node set that can cover all two-hop nodes according to the ranking of the comprehensive measurement indicators. S6, the node selected as the MPR calculates the directional link stability value with all nodes in the local MPR selection set, modifies the TC message format, appends the directional link stability value to the IP address of the included nodes, and broadcasts it through the omnidirectional RF antenna; S7: After receiving the TC message, if the node is the first to receive it and it is the source MPR node, it forwards it through the omnidirectional RF antenna, otherwise it does not forward it; S8: The node obtains the network topology and link stability values ​​based on the TC message and stores them in the local topology table. S9, the node converts the link stability value into the link cost value in the topology table through logarithmic operation, and uses the Dijkstra algorithm to calculate the entire network route and establish a routing table; S10: When a node encounters a demand for sending a business message, it forwards the message entirely through the FSO link according to the pre-built routing table.

2. The improved optimized link state routing protocol for drone swarms under the hybrid communication architecture according to claim 1 is characterized in that: The improved Hello message format includes the current location of the source node, the predicted location, the MPR selection set length value, the type and address of the neighbor node, and the omnidirectional link stability value of the one-hop symmetric neighbor; The omnidirectional link stability value of the neighbor node M of the source node S is calculated according to the following formula: Among them, d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum movement speed of node M; α is the angle between v and d; k v 、k t 、k d It is a constant parameter and should be adjusted according to actual conditions.

3. The improved optimized link state routing protocol for drone swarms under the hybrid communication architecture according to claim 1 is characterized in that: The implementation process of step S5 is as follows: The node coverage index that measures the coverage range of the neighbor nodes M of the source node S is calculated according to the following formula: The omnidirectional average two-hop link stability value of the neighbor node M of the source node S is calculated according to the following formula: The MPR selection set length index of the neighbor node M of the source node S is calculated according to the following formula: The comprehensive quality index of the neighbor node M of the source node S is calculated according to the following formula: CLQ=a*ALS+b*MSSLI+c*CDI Among them, len() is the length function of the set, N1(S) is the one-hop symmetric neighbor set of the source node S; N2(S,M) is the two-hop neighbor set connected to the source node S through the one-hop neighbor M; len(MSS M ) is the number of nodes selected as MPR nodes, which is provided by the Hello message of node M; a, b, and c are the weights of indicators ALS, MSSLI, and CDI, respectively, satisfying a+b+c=1; When selecting MPR nodes, nodes that are connected to some two-hop nodes by only one relay node are first selected as MPR nodes. Then, the CLQ value of each node is calculated. If multiple nodes have the same CLQ, the values ​​of ALS, MSSLI, and CDI are compared in turn, and the nodes are added to the MPR node set from high to low until all two-hop nodes are covered.

4. The improved optimized link state routing protocol for drone swarms under the hybrid communication architecture according to claim 1 is characterized in that: The modified TC message format includes the addresses and link stability values ​​of all nodes in the MPR selection set.

5. The improved optimized link state routing protocol for drone swarms under the hybrid communication architecture according to claim 1 is characterized in that: The directional link stability value in step S6 is: Among them, d o max represents the maximum communication distance of the omnidirectional antenna carried by the source node S; d is the position vector from the source node S to the neighbor node M; v is the relative velocity vector from the source node S to the neighbor node M; v max represents the maximum movement speed of node M; α is the angle between v and d; k ⊥ 、k t 、k / / is a constant parameter.

6. The improved optimized link state routing protocol for drone swarms under the hybrid communication architecture according to claim 1 is characterized in that: The link cost value in step S9 is: cost=-ln(LS d ) Among them, LS d is the directional link stability value mentioned above, and cost is the link cost value in the topology table.

7. A device, characterized in that: comprising a memory and a processor, wherein: a memory for storing computer programs capable of running on the processor; A processor is configured to, when running the computer program, execute the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described in any one of claims 1 to 6.

8. A storage medium, characterized in that: The storage medium stores a computer program, which, when executed by at least one processor, implements the steps of the improved optimized link state routing protocol for drone swarms under the hybrid communication architecture as described in any one of claims 1 to 6.

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