Multi-access method for fixed-wing unmanned aerial vehicle swarm network

Abstract

The invention relates to a multi-access method for a fixed-wing unmanned aerial vehicle swarm network, which can overcome the defects and deficiencies of the existing single multi-access protocol, and provides a hybrid multi-access protocol for accessing different network information by adopting a statistical priority multi-access protocol and a time division multi-access protocol according to time slot distribution on the basis of a multi-channel sending system. In the protocol, time-sensitive information is respectively inserted into different queues according to the service priorities of the time-sensitive information, whether the current time slot meets the sending condition of the time-sensitive information is judged, if so, the time-sensitive information of the corresponding priority is sent, common information is sent in the service time slot, and meanwhile, the time-sensitive information can be sent in the service time slot by reasonably arranging the occurrence frequency and interval of the time-sensitive time slot. And the transmission delay of the time-sensitive information is controlled. According to the hybrid multiple access protocol provided by the invention, the interaction of each node state and reconnaissance information in the whole network can be realized while the low-delay transmission of the time-sensitive information is met, so that the unmanned aerial vehicle swarm network or cooperation requirements in different scenes are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicle (UAV) swarm information interaction, and in particular relates to a multiple access method for a fixed-wing UAV swarm network. Background Art

[0002] A single drone has a single function and has limitations in collaborative search, intelligence transmission, situational awareness, etc. In order to improve the survivability and search efficiency of drones, the drone working mode has been transformed from point-to-point to swarm collaborative mode.

[0003] The drone swarm information interaction system is the foundation for drone interconnection and interoperability. It relays control commands between swarm nodes within a certain range. In scenarios such as large-scale drone collaborative search, coordinated attack, and coordinated reconnaissance and strike, drone swarms often maintain dense formations. To ensure flight safety and maintain formation, nodes must frequently exchange attitude and position information, individual status information, reconnaissance information, and time-sensitive target data. This ensures the network has the self-organizing and self-repairing capabilities to meet the needs of drone swarm collaborative search. Furthermore, to track fast-moving targets, the drone swarm information interaction system must possess low-latency transmission capabilities for time-sensitive information.

[0004] The Multiple Access Control (MAC) protocol for drone swarm information interaction systems describes the rules that each node in the network must follow when accessing a shared channel. This protocol determines when a node is allowed to send packets and controls its access to the physical layer. The MAC protocol describes how mobile nodes in a network efficiently share limited, unlimited broadband resources. As the underlying layer of the network protocol, the quality of the multiple access protocol directly impacts network performance metrics such as throughput and latency.

[0005] Multiple access protocols can be roughly divided into two categories based on the media access method: one is the MAC protocol based on the contention mechanism, and the other is the MAC protocol based on the allocation mechanism. In the MAC protocol based on the contention mechanism, there is no central node to uniformly allocate channel resources, and each node competes for the channel on demand. The advantage of this method is that it can ensure low-latency transmission of high-priority services, but the disadvantage is that it cannot completely avoid conflicts. In the MAC protocol based on the allocation mechanism, the allocation mechanism adopts a synchronous communication mode and allocates channel time to each node using a specified transmission time scheduling algorithm. Nodes occupy the channel within their allocated time. The advantage of this method is that the allocation of protocol time can achieve collision-free transmission of information, but the disadvantage is that it is difficult to ensure low latency for high-priority services.

[0006] Current multi-access protocols for drone swarm networking are primarily scheduling-based protocols, often employing time-division multiple access (TDMA) protocols to achieve multi-node channel access. While these protocols are easy to implement and exhibit minimal multi-access interference, they suffer from slow networking, inability to dynamically establish networks, difficulty scaling networks, and significant data latency. Furthermore, they cannot meet the low-latency transmission requirements for time-sensitive targets during drone swarm coordination and joint attack missions. Contention-based random access protocols, such as the Tactical Targeting Network Technology (TTNT), can achieve low-latency transmission of time-sensitive information, but are prone to network congestion when a large number of nodes are communicating simultaneously within the network. To address the advantages and disadvantages of contention-based and allocation-based MAC protocols, researchers have proposed hybrid access multiple access protocols, typified by the Z_MAC and Funneline MAC protocols. Both employ a hybrid access scheme using CSMA and TDMA, employing CSMA when channel resources are relatively idle and TDMA when resources are limited to resolve channel contention. However, it is difficult to ensure low-latency transmission of time-sensitive information. This is because: 1) When channel resources are relatively idle, if a high-priority service is being sent while other services are already being sent, the high-priority service will have to wait. 2) When resources are limited, using TDMA to send services will be limited by time slots, resulting in increased transmission latency.

[0007] In summary, the existing MAC protocols based on contention mechanisms and MAC multiple access protocols based on allocation mechanisms are difficult to meet the requirements of low-latency transmission of time-sensitive information while satisfying the business information interaction between nodes in large-scale drone swarm networks. Summary of the Invention

[0008] The technical problem solved by the present invention is to overcome the shortcomings and deficiencies of the existing single multiple access protocol and provide a multiple access method for a fixed-wing UAV swarm network.

[0009] The technical solution for achieving the purpose of the present invention is: a multiple access method for a fixed-wing UAV swarm network, comprising the following steps:

[0010] Step 1: Based on the multi-channel transmission system, the information generated by the application layer is divided into time-sensitive information and business information. If it is time-sensitive information, proceed to step 2; otherwise, proceed to step 10;

[0011] Step 2: Determine the priority of the information and insert the time-sensitive information between the original information queues in order of priority. The time-sensitive information queues inserted after the a-th original information queue are represented as: qa1, qa2, …, qan, where n is the number of time-sensitive information that can be inserted after the a-th original information queue, and a ≥ 2;

[0012] Step 3: According to the timing allocation, determine the current time slot status. If it is a time-sensitive time slot, set m = 1 and go to step 4;

[0013] Step 4: Check whether the current highest priority time-sensitive information q2m is empty. If it is empty, go to step 9; if it is not empty, go to step 5;

[0014] Step 5: Determine whether the time-sensitive information q2m has timed out. If so, remove the time-sensitive information q2m and go to step 4. If not, go to step 6.

[0015] Step 6: Use the sliding average method to calculate the current busyness of the channel;

[0016] Step 7: Compare the calculated channel busyness with the busy / idle threshold set for the current highest priority service. If the current channel busyness is less than the set busy / idle threshold, access the channel and proceed to step 8, monitoring the channel busyness. Otherwise, stop sending immediately.

[0017] Step 8: Use the backoff algorithm to determine the backoff time and perform random backoff. After the backoff is completed, go to step 5;

[0018] Step 9: Let m=m+1, m<=n, and go to step 4;

[0019] Step 10: insert the service information into the tail of the first information queue q1, and determine whether the current time is the time slot for transmitting the service information of this node. If so, the first information queue q1 after the service information is inserted will be transmitted in sequence.

[0020] Preferably, the specific formula for calculating the current busy / idle degree of the channel chan_acc using the sliding average method is:

[0021]

[0022] Wherein, p and q are integers less than n, and p+q+1=n, X k+i The busyness of the channel at the current moment.

[0023] Preferably, the random backoff time t_dly_m is specifically:

[0024] t_dly_m=rand(T(m+2) 2 / 5)

[0025] Wherein, T is the sliding average window size, and rand is the random function. Compared with the prior art, the present invention has the following significant advantages:

[0026] The present invention combines the advantages of the statistical priority multiple access (SPMA) protocol and the time division multiple access (TDMA) protocol to meet the low-latency transmission requirements of time-sensitive information while enabling the interaction of business information among all nodes in the entire network. The present invention is suitable for drone swarms, clusters, or missile swarm networks, and can meet the needs of drone networks or missile swarms in different scenarios such as collaborative search, collaborative attack, and collaborative reconnaissance and strike. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without any creative work.

[0028] Figure 1 This is a flow chart of a multiple access method for a fixed-wing UAV swarm network according to the present invention.

[0029] Figure 2 This is the time slot allocation diagram of the present invention. DETAILED DESCRIPTION

[0030] See also Figure 1 , Figure 2 In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without any creative work.

[0031] A multiple access method for a fixed-wing UAV swarm network, characterized by comprising the following steps:

[0032] Step 1: Based on the multi-channel transmission system, the information msg generated by the application layer is divided into time-sensitive information and business information. If it is time-sensitive information, proceed to step 2; otherwise, proceed to step 10;

[0033] Step 2: Determine the priority of the message msg and insert the time-sensitive message between the original message queues in order of priority. The time-sensitive message queues inserted after the a-th original message queue are represented as: qa1, qa2, ..., qan, where n is the number of time-sensitive messages that can be inserted after the a-th original message queue, and a ≥ 2;

[0034] qa1, qa2, …, qan are the queues with time-sensitive information inserted after the ath original information queue. They are arranged in order of priority. That is, q21 is the time-sensitive information with the highest priority and is arranged behind the original information queue q2. If only the L time-sensitive information with the highest priority can be arranged between the original information queues q2 and q3, the time-sensitive information with the later priority will be arranged in order of priority between the original queues q3 and q4, and so on.

[0035] The low-priority service queue sends information in the time slot specified by TDMA, and the high-priority queue sends information in a competitive manner based on the channel busyness and priority.

[0036] Step 3: According to the timing allocation, determine the current time slot status. If it is a time-sensitive time slot, set m = 1 and go to step 4;

[0037] Step 4: Check whether the current highest priority time-sensitive information q2m is empty. If it is empty, go to step 9; if it is not empty, go to step 5;

[0038] Step 5: Determine whether the time-sensitive information q2m has timed out. If so, remove the time-sensitive information q2m and go to step 4. If not, go to step 6.

[0039] Step 6: Use the sliding average method to calculate the current busyness of the channel chan_acc. The specific formula is:

[0040]

[0041] Wherein, p and q are integers less than n, and p+q+1=n, X k+i The busyness of the channel at the current moment.

[0042] Step 7: Compare the calculated channel busyness with the busy / idle threshold set for the current highest priority service. If the current channel busyness is less than the set busy / idle threshold, access the channel and proceed to step 8, monitoring the channel busyness. Otherwise, stop sending immediately.

[0043] Step 8: Use the backoff algorithm to determine the backoff time and perform a random backoff. After the backoff is complete, go to step 5 and try sending again. The random backoff time t_dly_m is:

[0044] t_dly_m=rand(T(m+2) 2 / 5)

[0045] Among them, T is the size of the sliding average window, and rand is a random function. If the channel busy / idle degree chan_acc does not allow the transmission of the current service, then randomly back off for a period of time and then try to transmit the current service again. The back-off time is determined by a random function related to the service priority. This back-off time can effectively avoid channel conflicts and reduce the transmission delay of high-priority services.

[0046] Step 9: Let m = m + 1, m <= n, and go to Step 4;

[0047] Step 10: Insert the service information into the tail of the first information queue q1, and determine whether the current moment is the service information transmission time slot of this node. If so, the first information queue q1 after inserting the service information is transmitted in sequence.

[0048] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific embodiments taking the reconnaissance and strike UAV swarm network as an example.

[0049] Step 1: Classify the information msg generated by the application layer. The time-sensitive information goes to Step 2, and the service information goes to Step 10;

[0050] Step 2: Time-sensitive information: Judge the priority of the service msg, and insert it into different queues q21, q22,..., q25 according to different priorities;

[0051] Step 3: According to the timing allocation, judge the current time slot. If it is a time-sensitive time slot, then m = 1, and go to Step 4;

[0052] Step 4: Check whether the current highest-priority queue q2m is empty. If it is empty, go to Step 9. If it is not empty, go to Step 5;

[0053] Step 5: Judge whether the information in the queue q2m has timed out. If it has timed out, remove the queue and go to Step 4. If it has not timed out, go to Step 6;

[0054] Step 6: Use the method of sliding average statistics to quickly count the channel busy / idle degree chan_acc;

[0055]

[0056] Among them, p = 25, q = 35.

[0057] Step 7: Compare with the busy / idle threshold C_set_m set for the current highest-priority service. When the channel busy / idle degree chan_acc < C_set_m, access the channel and simultaneously monitor the channel busy / idle degree. When chan_acc >= C_set_m, immediately stop sending, otherwise go to Step 8;

[0058] Step 8: Use the improved exponential backoff algorithm to randomly back off for a time period of t_dly_m. After the backoff period ends, go to step 5 and try sending again.

[0059] t_dly_m=random(0.02*(p+2) 2 / 5)

[0060] Step 9: Set m=m+1 (m<=5), and go to step 4;

[0061] Step 10: Insert the message msg to the end of queue q1 and determine whether the current time is the transmission time slot of this node. If so, queue q1 will transmit in turn;

[0062] The present invention combines the advantages and disadvantages of the contention mechanism MAC protocol and the allocation mechanism MAC protocol to propose a hybrid multiple access protocol. This protocol is based on a multi-channel transmission mechanism and can allow multiple users to transmit signals simultaneously at the same time. The multi-channel can adopt an FDMA system or a frequency hopping system. When a high-priority service needs to be transmitted, the busy-idle threshold set for the priority service is compared with the current channel busy-idle level. If the channel busy-idle level allows transmission, the current service is transmitted immediately; otherwise, a random backoff period related to the priority is applied before transmission is attempted. At the same time, TDMA is used to control the transmission time slots of low-priority services. Since low-priority services are transmitted within the specified time slots, conflicts with high-priority services can be effectively avoided. This ensures low latency for high-priority services while preventing low-priority services from starving due to lack of time slots. The transmission delay of time-sensitive information is controlled by rationally arranging the frequency and interval of time-sensitive time slots.

Claims

1. A multiple access method for a fixed-wing UAV swarm network, characterized in that: The following steps are involved: Step 1: Based on the multi-channel transmission system, the information generated by the application layer is divided into time-sensitive information and business information. If it is time-sensitive information, proceed to step 2; otherwise, proceed to step 10; Step 2: Determine the priority of the information and insert the time-sensitive information between the original information queues in order of priority. The time-sensitive information queues inserted after the a-th original information queue are represented as: qa1, qa2, …, qan, where n is the number of time-sensitive information that can be inserted after the a-th original information queue, and a ≥ 2; Step 3: According to the timing allocation, determine the current time slot status. If it is a time-sensitive time slot, set m = 1 and go to step 4; Step 4: Check whether the current highest priority time-sensitive information q2m is empty. If it is empty, go to step 9; if it is not empty, go to step 5; Step 5: Determine whether the time-sensitive information q2m has timed out. If so, remove the time-sensitive information q2m and go to step 4. If not, go to step 6. Step 6: Use the sliding average method to calculate the current busyness of the channel; Step 7: Compare the calculated channel busyness with the busy / idle threshold set for the current highest priority service. If the current channel busyness is less than the set busy / idle threshold, access the channel and proceed to step 8, monitoring the channel busyness. Otherwise, stop sending immediately. Step 8: Use the backoff algorithm to determine the backoff time and perform random backoff. After the backoff is completed, go to step 5; Step 9: Let m=m+1, m<=n, and go to step 4; Step 10: insert the service information into the tail of the first information queue q1, and determine whether the current time is the time slot for transmitting the service information of this node. If so, the first information queue q1 after the service information is inserted will be transmitted in sequence.

2. The multiple access method for a fixed-wing UAV swarm network according to claim 1, characterized in that: The specific formula for calculating the current busy / idle degree of the channel chan_acc using the sliding average method is: Wherein, p and q are integers less than n, and p+q+1=n, X k+i The busyness of the channel at the current moment.

3. The multiple access method for a fixed-wing UAV swarm network according to claim 1, characterized in that: The random backoff time t_dly_m is specifically: t_dly_m=rand(T(m+2) 2 / 5) Where T is the sliding average window size and rand is the random function.

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