An adaptive unmanned cluster MAC layer hybrid networking method

Abstract

The application discloses an adaptive unmanned cluster MAC layer hybrid networking method, and belongs to the wireless communication technical field. The application solves the problems that the existing method is difficult to adapt to the dynamic change of the node quantity, the time slot is difficult to allocate when the node quantity is large, and congestion conflict and channel resource waste are easily generated frequently when the communication traffic of part of nodes is large. The application designs a protocol frame structure, a part of time slots in the protocol frame structure is designed as a dynamic competition window, and the other part of time slots is set as fixed time slots. In the initialization stage, the node accesses the network through the competition window, and the priority of the accessed node is allocated, the priority is dynamically adjusted according to the network congestion degree of the node in the network running process, the high-priority node can be allocated to the fixed time slot and has higher competition priority in the competition window, and the low-priority node participates in the time slot competition in the competition window, and then the business data receiving and transmitting are carried out after the competition is successful. The method can be applied to the wireless communication technical field.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to an adaptive unmanned cluster MAC (Medium Access Control) layer hybrid networking method. Background Technology

[0002] In large-scale unmanned cluster networks, the number of nodes is enormous and dynamically changing. Traditional TDMA (Time Division Multiple Access) protocols are difficult to adapt to the dynamic changes in the number of nodes, and allocating time slots becomes difficult when the number of nodes increases significantly. On the other hand, CSMA (Carrier Sense Multiple Access) protocols are prone to frequent congestion conflicts and waste of channel resources when some nodes have high traffic volumes. Therefore, a single TDMA or CSMA protocol cannot simultaneously meet the requirements of high efficiency and adaptability in the utilization of channel resources in large-scale unmanned cluster networks.

[0003] In summary, to address the difficulties in allocating time slots using existing methods when the number of nodes is large, and the frequent congestion conflicts and waste of channel resources when some nodes have high communication traffic, a new unmanned cluster MAC layer hybrid networking method is proposed to solve this problem urgently. Summary of the Invention

[0004] The purpose of this invention is to address the problems that existing methods struggle to adapt to dynamic changes in the number of nodes, have difficulty allocating time slots when the number of nodes is large, and are prone to frequent congestion conflicts and waste of channel resources when some nodes have high communication traffic. Therefore, an adaptive unmanned cluster MAC layer hybrid networking method is proposed.

[0005] The technical solution adopted by this invention to solve the above-mentioned technical problems is: an adaptive unmanned cluster MAC layer hybrid networking method, the method specifically including the following steps:

[0006] Step 1: Initialize the protocol frame length of the MAC layer to M service time slots;

[0007] Step 2: Initialize the protocol frame count t = 1;

[0008] Step 3: Determine whether the t-th protocol frame has reached the node priority update cycle, wherein the node priority update cycle is set to 10M;

[0009] If the node priority update cycle is reached in the t-th protocol frame, then before the start of the t-th protocol frame, collect the network congestion index of the historical access nodes, update the priority of the historical access nodes according to the collected network congestion index, and then execute step four.

[0010] If the t-th protocol frame has not reached the node priority update cycle, proceed directly to step five;

[0011] Step 4: Determine the window positions of fixed time slots and contention time slots based on the updated historical access node priorities and the priorities of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to the allocated contention probability within the contention time slot, and only send and receive service data after successfully competing.

[0012] After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three.

[0013] Step 5: Determine the window positions of fixed time slots and contention time slots based on the priority of historical access nodes and the priority of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to the allocated contention probability within the contention time slot. Service data is sent and received only after successful contention.

[0014] After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three.

[0015] Furthermore, the method broadcasts the window position information of the fixed time slot and contention time slot within the current protocol frame of the MAC layer in real time through the network controller.

[0016] Furthermore, the new node obtains the contention slot window position based on the information broadcast by the network controller, and then randomly selects a contention slot within the contention slot window to send an access request message;

[0017] The access request message includes the node ID, the estimated cache queue length, the estimated data packet latency, and the estimated packet loss rate.

[0018] Furthermore, the priority of the node is calculated as follows:

[0019]

[0020] Where BL represents the node's buffer queue length, PD represents the node's data packet latency, PLR represents the node's packet loss rate, ω1, ω2 and ω3 are all weights, P represents the node's priority, α represents the buffer queue length threshold, β represents the data packet latency threshold, and γ represents the packet loss rate threshold.

[0021] If a node's priority P ≥ 0.7, then the node is a high-priority node; if a node's priority P < 0.7, then the node is a low-priority node.

[0022] Furthermore, the specific process of step four is as follows:

[0023] Step 4: 1. Determine if there are any nodes that have not communicated in the (t-3)th, (t-2)th, and (t-1)th protocol frames;

[0024] If a node fails to communicate in the (t-3), (t-2), and (t-1)th protocol frames, the node exits the network from the contention window, and step four-two is then executed for the remaining nodes.

[0025] If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step four two.

[0026] Step 4.2: For node a, which had high priority in the previous cycle and has a low priority after the update:

[0027] If node a occupies a fixed time slot in the previous protocol frame, then after releasing the fixed time slot resources of node a, node a's transmit and receive services will be allocated to the contention time slot window, and the contention probability of node a will be set to 20%.

[0028] If node a did not occupy a fixed time slot in the previous protocol frame, then node a's transmit and receive services will still be allocated to the contention time slot window, and node a's contention probability will be adjusted to 20%.

[0029] Then proceed to step four three;

[0030] Step 4. Count the number N of high-priority nodes in the t-th protocol frame. The high-priority nodes in the t-th protocol frame include nodes that were high-priority in the previous period and whose priority remains high after the update, nodes that were low-priority in the previous period and whose priority becomes high after the update, and high-priority nodes that are newly connected in the (t-1)-th protocol frame.

[0031] If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M, then a fixed time slot is allocated to each high-priority node, and the contention probability of each high-priority node in the contention time slot is set to 80%; then proceed to step four.

[0032] If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step four.

[0033] Step 4: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception.

[0034] If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to steps four and five; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to steps four and six.

[0035] If there is no high-priority node that meets condition (1), proceed directly to step four and seven.

[0036] Steps 4 and 5: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80%, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame.

[0037] Then, randomly select 0.9M nodes from the remaining high-priority nodes, and assign a fixed time slot to each selected high-priority node. The contention probability of each selected high-priority node in the contention time slot is set to 80%. Move each high-priority node that was not selected to the contention time slot, and set the contention probability of each high-priority node that was not selected in the contention time slot to 80%.

[0038] Then proceed to step four eight;

[0039] Step 46: Randomly select N-0.9M high-priority nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%.

[0040] Then proceed to step four eight;

[0041] Step 47: Randomly select 0.9M high-priority nodes from all high-priority nodes, and assign a fixed time slot to each selected high-priority node. Set the contention probability of each selected high-priority node in the contention time slot to 80%. Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node in the contention time slot to 80%.

[0042] Then proceed to step four eight;

[0043] Step 48: Assign low-priority nodes in the t-th protocol frame to contention slots, and set the contention probability of each low-priority node in the contention slot to 20%.

[0044] Furthermore, the specific process of step five is as follows:

[0045] Step 51: Determine if there are any nodes that have not communicated in the (t-3)th, (t-2)th, and (t-1)th protocol frames;

[0046] If a node fails to communicate in the (t-3), (t-2), and (t-1)th protocol frames, the node exits the network from the contention window, and step 5.2 is then executed for the remaining nodes.

[0047] If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step 5.2.

[0048] Step 5.2: Count the number N of high-priority nodes in the t-th protocol frame, where the high-priority nodes in the t-th protocol frame include historically accessed high-priority nodes and newly accessed high-priority nodes in the (t-1)-th protocol frame.

[0049] If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M, then a fixed time slot is allocated to each high-priority node, and the contention probability of each high-priority node in the contention time slot is set to 80%; then proceed to step five and seven.

[0050] If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step five three.

[0051] Step 53: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception.

[0052] If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to step five four; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to step five five.

[0053] If there is no high-priority node that meets condition (1), proceed directly to steps five and six.

[0054] Step 54: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80% for all of them, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame.

[0055] Then, randomly select 0.9M nodes from the remaining high-priority nodes, and assign a fixed time slot to each selected high-priority node. The contention probability of each selected high-priority node in the contention time slot is set to 80%. Move each high-priority node that was not selected to the contention time slot, and set the contention probability of each high-priority node that was not selected in the contention time slot to 80%.

[0056] Then proceed to step five or seven;

[0057] Step 5: Randomly select N-0.9M high-priority nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%.

[0058] Then proceed to step five or seven;

[0059] Steps 5 and 6: Randomly select 0.9M nodes from all high-priority nodes, assign a fixed time slot to each selected high-priority node, and set the contention probability of each selected high-priority node in the contention time slot to 80%; Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node in the contention time slot to 80%.

[0060] Then proceed to step five or seven;

[0061] Step 57: Assign the low-priority nodes in the t-th protocol frame to the contention slot, and set the contention probability of each low-priority node in the contention slot to 20%.

[0062] Furthermore, when a node conflict occurs within the competition time slot, the high-priority node continues to participate in the time slot competition in the next competition time slot, while the low-priority node goes back to participate in the time slot competition after 5 competition time slots.

[0063] The beneficial effects of this invention are:

[0064] This invention designs a protocol frame structure, using dynamic CSMA contention windows for some time slots and setting the remaining time slots as fixed time slots. During initialization, nodes access the network through contention windows, and priorities are assigned to these nodes. As the network operates, priorities are dynamically adjusted based on network congestion levels. High-priority nodes are allocated fixed time slots and enjoy higher contention priority within the contention window, while low-priority nodes compete for time slots within the contention window. Successful competition allows for the transmission and reception of service data. This invention dynamically adjusts node priorities, fixed time slot allocations, and contention priorities within the contention window to adapt to real-time changes in network node communication traffic and the number of nodes, effectively avoiding congestion conflicts and channel resource waste, and ensuring maximum utilization of network channel resources. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the frame structure of the MAC layer hybrid networking method of the present invention;

[0066] Figure 2 This is a flowchart illustrating the node dynamic priority update mechanism and time slot allocation of the present invention;

[0067] Figure 3 This is a schematic diagram of the frame structure when a small number of nodes are initially connected in this invention;

[0068] Figure 4 This is a schematic diagram of the time slot reallocation frame structure in the unsaturated state when the node priority period is updated according to the present invention.

[0069] Figure 5 This is a schematic diagram of the hybrid MAC protocol frame structure reaching saturation state according to the present invention;

[0070] Figure 6 This is a schematic diagram of the frame structure for time slot reallocation after node priority update when the hybrid MAC protocol frame structure of the present invention reaches saturation.

[0071] Figure 7 This is a schematic diagram illustrating the transition of the hybrid MAC protocol frame structure from saturation to non-saturation in this invention.

[0072] Figure 8 This is a schematic diagram illustrating the exit of a failed node from the network according to the present invention. Detailed Implementation

[0073] Specific implementation method one: Combining Figure 2 This embodiment describes an adaptive unmanned cluster MAC layer hybrid networking method, which specifically includes the following steps:

[0074] Step 1: Initialize the protocol frame length of the MAC layer to M service time slots (in this invention, M is 100, and the length of each time slot is 1ms, that is, the period of the protocol frame is 100ms).

[0075] Step 2: Initialize the protocol frame count t = 1;

[0076] Step 3: Determine whether the node priority update cycle has been reached in the t-th protocol frame (when t=1, the node priority update cycle is assumed to have been reached; the network congestion index of each node in the MAC layer is counted before the start of the first protocol frame, and the priority of each node is calculated). The node priority update cycle is set to 10M (that is, in this invention, the network congestion index of the node needs to be collected after the 10th protocol frame, after the 20th protocol frame, and after the 30th protocol frame, and the node priority is updated, and so on, the node priority is updated once every 10 protocol frames. Within the 10 protocol frames of one update cycle, the node priority remains unchanged).

[0077] The priority of newly added nodes in the previous protocol frame is calculated based on the initialization parameters. Then, the priority of the nodes is updated once a time by collecting network congestion indicators at each priority update cycle.

[0078] If the node priority update cycle is reached in the t-th protocol frame, then before the start of the t-th protocol frame, collect the network congestion index of the historical access nodes, update the priority of the historical access nodes according to the collected network congestion index, and then execute step four.

[0079] If the t-th protocol frame has not reached the node priority update cycle, proceed directly to step five;

[0080] Step 4: Determine the window positions of fixed time slots (in a fixed time slot, only the node allocated to that time slot will send and receive service data, i.e., only the node allocated to that time slot will communicate) and contention time slots based on the updated historical access node priorities and the priorities of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to their allocated contention probabilities within the contention time slots, and only send and receive service data after successfully competing.

[0081] After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three.

[0082] Step 5: Determine the window positions of fixed time slots and contention time slots based on the historical access node priorities (which do not need to be updated at present) and the priorities of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to the allocated contention probability within the contention time slot, and only send and receive service data after successfully competing.

[0083] After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three.

[0084] It should be noted that the unmanned swarm of the present invention refers to a swarm including drones and unmanned vehicles, with each unmanned system acting as a node, and the communication process between nodes can be achieved through the method of the present invention.

[0085] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the method uses a network controller to broadcast in real time the window position information of the fixed time slot and contention time slot within the current protocol frame of the MAC layer.

[0086] The other steps and parameters are the same as in Specific Implementation Method 1.

[0087] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the new node obtains the contention slot window position based on the information broadcast by the network controller, and then randomly selects a contention slot from the contention slot window to send the access request message.

[0088] The access request message includes the node ID, the estimated cache queue length, the estimated data packet latency, and the estimated packet loss rate.

[0089] Other steps and parameters are the same as in specific implementation method one or two.

[0090] like Figure 3 The diagram illustrates the frame structure during the initial access of a small number of nodes according to the present invention. When a new node joins the network, it first listens to the hybrid MAC protocol frame structure information broadcast by the network controller to obtain the position and length of the contention window. Within the contention window, the node randomly selects a time slot to send an access request message. The message content includes the node ID, buffer queue length, packet delay, and estimated packet loss rate. After initiating the access request message, the node can compete for network access within the contention window.

[0091] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the priority of the node is calculated as follows:

[0092]

[0093] Where BL represents the node's buffer queue length, PD represents the node's data packet delay, PLR represents the node's packet loss rate, ω1, ω2 and ω3 are all weights (set to 0.5, 0.3 and 0.2 respectively), P represents the node's priority, α represents the buffer queue length threshold, β represents the data packet delay threshold, and γ represents the packet loss rate threshold.

[0094] If a node's priority P ≥ 0.7, then the node is a high-priority node and its priority flag is set to 1; if a node's priority P < 0.7, then the node is a low-priority node and its priority flag is set to 0.

[0095] The other steps and parameters are the same as those in one of the specific implementation methods one to three.

[0096] In this invention, the values ​​of thresholds α, β, and γ can be obtained from historical data (in this invention, threshold α is 100, threshold β is 500ms, and threshold γ is 10%). Generally, the node's buffer queue length will not exceed threshold α, packet latency will not exceed threshold β, and packet loss rate will not exceed γ. Based on thresholds α, β, and γ, the node's network congestion index can be normalized, and then the node priority can be calculated based on the normalized network congestion index. The priority updates for historically accessed nodes and the priorities for newly accessed nodes are both calculated using the method of this embodiment.

[0097] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the specific process of step four is as follows:

[0098] Step 4: 1. Determine if there are any nodes that have not communicated (i.e., have not sent or received services) in the (t-3)th, (t-2)th, and (t-1)th protocol frames;

[0099] If a node fails to communicate within the (t-3), (t-2), and (t-1)th protocol frames, then that node exits the network from the contention window. Figure 8 The diagram shows the exit of a failed node from the network according to the present invention. When a node fails to communicate for 3 consecutive frames, if the node is a high-priority node, the node automatically releases its fixed time slot resources and exits the network from the contention window; if the node is a low-priority node, it directly exits the network from the contention window, and then the remaining nodes continue to execute step four two.

[0100] If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step four two.

[0101] Step 4.2: For node a, which had a high priority in the previous cycle (referring to the node priority update cycle) and has a low priority after the update:

[0102] If node a occupies a fixed time slot in the previous protocol frame, then after releasing the fixed time slot resources of node a, node a's transmit and receive services will be allocated to the contention time slot window, and the contention probability of node a will be set to 20%.

[0103] If node a did not occupy a fixed time slot in the previous protocol frame (i.e., the fixed time slot in the previous protocol frame was saturated, and node a was not allocated a fixed time slot in the previous protocol frame), then... Figure 5The diagram shows the hybrid MAC protocol frame structure reaching saturation. The frame structure has 90 fixed time slots. Correspondingly, the number of contention window time slots in the frame structure is reduced to a minimum of 10. Then, the transmit and receive services of node a are still allocated to the contention time slot window, and the contention probability of node a is adjusted to 20%.

[0104] Then proceed to step four three;

[0105] Step 4. Count the number N of high-priority nodes in the t-th protocol frame. The high-priority nodes in the t-th protocol frame include nodes that were high-priority in the previous period and whose priority remains high after the update, nodes that were low-priority in the previous period and whose priority becomes high after the update, and high-priority nodes that are newly connected in the (t-1)-th protocol frame.

[0106] If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M (i.e., the length of the fixed time slot cannot exceed 90% of the protocol frame length, and when the proportion of fixed time slots reaches 90%, it reaches a saturation state), then allocate a fixed time slot to each high-priority node and set the contention probability of each high-priority node in the contention time slot to 80%; then execute step four eight.

[0107] If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step four.

[0108] Step 4: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception.

[0109] If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to steps four and five; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to steps four and six.

[0110] If there is no high-priority node that meets condition (1), proceed directly to step four and seven.

[0111] Steps 4 and 5: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80%, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame.

[0112] Then, randomly select 0.9M nodes from the remaining high-priority nodes (i.e., high-priority nodes that do not meet condition (1)), assign a fixed time slot to each selected high-priority node, and set the competition probability of each selected high-priority node in the competition time slot to 80%; transfer each high-priority node that was not selected to the competition time slot, and set the competition probability of each high-priority node that was not selected in the competition time slot to 80%;

[0113] Then proceed to step four eight;

[0114] Step 46: Randomly select N-0.9M high-priority nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%.

[0115] Then proceed to step four eight;

[0116] Step 47: Randomly select 0.9M high-priority nodes from all high-priority nodes, and assign a fixed time slot to each selected high-priority node. Set the contention probability of each selected high-priority node in the contention time slot to 80%. Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node in the contention time slot to 80%.

[0117] Then proceed to step four eight;

[0118] Step 48: Assign low-priority nodes in the t-th protocol frame to contention slots, and set the contention probability of each low-priority node in the contention slot to 20%.

[0119] The other steps and parameters are the same as those in one of the specific implementation methods one to four.

[0120] After determining the number of fixed time slots and contention time slots based on node priorities, within the protocol frame, the earlier time slots are fixed time slots, and the later time slots are contention time slots, thus determining the window positions for fixed and contention time slots. For example... Figure 1 The diagram shows the frame structure of the MAC layer hybrid networking method of the present invention. A node with high priority is allocated one fixed time slot resource and is set to participate in the contention of time slots with an 80% probability in the contention window; a node with low priority is not allocated a fixed time slot resource and is set to participate in the contention of time slots with a 20% probability in the contention window; if there are k high priority nodes, the contention window time slots are 100-k (the contention window time slots are not less than 10).

[0121] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the specific process of step five is as follows:

[0122] Step 51: Determine if there are any nodes that have not communicated (i.e., have not sent or received services) in the (t-3)th, (t-2)th, and (t-1)th protocol frames;

[0123] If a node fails to communicate in the (t-3), (t-2), and (t-1)th protocol frames, the node exits the network from the contention window (i.e., the node is rendered invalid), and then step 52 is executed for the remaining nodes.

[0124] If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step 5.2.

[0125] Step 5.2: Count the number N of high-priority nodes in the t-th protocol frame, where the high-priority nodes in the t-th protocol frame include historically accessed high-priority nodes and newly accessed high-priority nodes in the (t-1)-th protocol frame.

[0126] If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M (i.e., the length of the fixed time slot cannot exceed 90% of the protocol frame length, and when the proportion of fixed time slots reaches 90%, it reaches a saturation state), then allocate a fixed time slot to each high-priority node and set the contention probability of each high-priority node in the contention time slot to 80%; then execute step five and seven.

[0127] If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step five three.

[0128] Step 53: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception.

[0129] If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to step five four; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to step five five.

[0130] If there is no high-priority node that meets condition (1), proceed directly to steps five and six.

[0131] Step 54: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80% for all of them, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame.

[0132] Then, randomly select 0.9M nodes from the remaining high-priority nodes, and assign a fixed time slot to each selected high-priority node. The contention probability of each selected high-priority node in the contention time slot is set to 80%. Move each high-priority node that was not selected to the contention time slot, and set the contention probability of each high-priority node that was not selected in the contention time slot to 80%.

[0133] Then proceed to step five or seven;

[0134] Step 5: Randomly select N-0.9M high-priority nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%.

[0135] Then proceed to step five or seven;

[0136] Steps 5 and 6: Randomly select 0.9M nodes from all high-priority nodes, assign a fixed time slot to each selected high-priority node, and set the contention probability of each selected high-priority node in the contention time slot to 80%; Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node in the contention time slot to 80%.

[0137] Then proceed to step five or seven;

[0138] Step 57: Assign the low-priority nodes in the t-th protocol frame to the contention slot, and set the contention probability of each low-priority node in the contention slot to 20%.

[0139] The other steps and parameters are the same as those in one of the specific implementation methods one to five.

[0140] like Figure 4The diagram illustrates the frame structure for time slot reallocation when the node priority update cycle is reached, as per the present invention. When there are too many high-priority nodes in the network, the network controller releases the fixed time slot resources of nodes that were high priority in the previous cycle but have been adjusted to low priority in the current cycle, allocates their service transmission and reception to the contention window, and reduces their contention probability to 20%. For nodes that were low priority in the previous cycle but have been adjusted to high priority in the current cycle, when the network's fixed time slots are not saturated, the network controller will directly allocate new fixed time slot resources to them and increase their contention probability in the contention window to 80%. When the network's fixed time slots are saturated, the network controller will randomly process them, either allocating fixed time slots or transferring them to contention slots. However, regardless of the situation, their contention probability within a contention slot remains at 80%. Assuming that after the adjustments within the above listening period, the ratio of fixed time slots to contention time slots has not yet reached saturation (i.e., the proportion of fixed time slots is less than 90% and the proportion of contention time slots is greater than 10%), if m high-priority nodes are adjusted to low priority and n low-priority nodes are adjusted to high priority, then the number of fixed time slot resources in the frame structure of the adjusted period becomes k-m+n, and the corresponding number of contention window time slots becomes 100-k+mn. Each node in the network will then perform communication services in the new period according to the adjusted time slot allocation.

[0141] like Figure 6 The diagram illustrates the time slot reallocation frame structure after a periodic update when the hybrid MAC protocol frame structure reaches saturation. When the network controller detects that the hybrid MAC protocol frame structure has reached saturation within a certain period, if no new nodes are upgraded to high priority in the current period, nodes downgraded to low priority need to release their fixed time slot resources and be downgraded to low priority nodes. If new nodes are upgraded to high priority in the current period, the network controller will randomly select some or all nodes from those nodes that were allocated fixed time slots in the previous protocol frame and did not perform service transmission or reception in the previous protocol frame (the number of nodes selected needs to be determined based on the network saturation level), and release the fixed time slot resources of the selected nodes. When a node's fixed time slot is released, its services will be transferred to the contention window. Its contention probability will remain unchanged at 80% within this protocol frame. After releasing some fixed time slot resources, they will be used to allocate time slots to other high-priority nodes. If a node's priority is updated to high priority when the next priority update cycle arrives, the fixed time slot allocation process for high-priority nodes will proceed normally. If a node's priority is updated to low priority when the next priority update cycle arrives, the network controller will also reduce its contention probability in the contention window to 20%, thus officially adjusting it to a low-priority node.

[0142] like Figure 7The diagram illustrates the transition of the hybrid MAC protocol frame structure from saturation to desaturation in this invention. The network controller detects a transition from saturation to desaturation within a certain period, specifically when the number of fixed time slots in the frame structure is less than 90 and the number of contention window time slots is greater than 10 at the start of the current period.

[0143] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that when a node conflict occurs within the contention time slot, the high-priority node continues to participate in the time slot contention in the next contention time slot, while the low-priority node continues to participate in the time slot contention after backing off for 5 contention time slots.

[0144] The other steps and parameters are the same as those in one of the specific implementation methods one to six.

[0145] The above examples of the present invention are merely illustrative of the computational model and process of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is impossible to exhaustively list all possible implementations here. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An adaptive unmanned cluster MAC layer hybrid networking method, characterized in that, The method specifically includes the following steps: Step 1: Initialize the protocol frame length of the MAC layer to M service time slots; Step 2: Initialize the protocol frame count t=1; Step 3: Determine whether the t-th protocol frame has reached the node priority update cycle, wherein the node priority update cycle is set to 10M; If the node priority update cycle is reached in the t-th protocol frame, then before the start of the t-th protocol frame, collect the network congestion index of the historical access nodes, update the priority of the historical access nodes according to the collected network congestion index, and then execute step four. The priority of the node is calculated as follows: in, Indicates the length of the node's cache queue. Indicates the packet latency of a node. This represents the packet loss rate of a node. , and All are weights. Indicates the priority of the node. Indicates the cache queue length threshold. Indicates the data packet delay threshold. This represents the packet loss rate threshold; If the node's priority If the priority is 0.7, then the node is a high-priority node; if the node's priority is... If the value is 0.7, then the node is a low-priority node; If the t-th protocol frame has not reached the node priority update cycle, proceed directly to step five; Step 4: Determine the window positions of fixed time slots and contention time slots based on the updated historical access node priorities and the priorities of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to the allocated contention probability within the contention time slot, and only send and receive service data after successfully competing. After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three. The specific process of step four is as follows: Step 4:

1. Determine if there are any nodes that have not communicated in the (t-3)th, (t-2)th, and (t-1)th protocol frames; If a node fails to communicate in the (t-3), (t-2), and (t-1)th protocol frames, the node exits the network from the contention window, and step four-two is then executed for the remaining nodes. If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step four two. Step 4.2: For node a, which had high priority in the previous cycle and has a low priority after the update: If node a occupies a fixed time slot in the previous protocol frame, then after releasing the fixed time slot resource of node a, node a's transmit and receive services will be allocated to the contention time slot window, and the contention probability of node a will be set to 20%. If node a did not occupy a fixed time slot in the previous protocol frame, then node a's transmit and receive services will still be allocated to the contention time slot window, and node a's contention probability will be adjusted to 20%. Then proceed to step four three; Step 4. Count the number N of high-priority nodes in the t-th protocol frame. The high-priority nodes in the t-th protocol frame include nodes that were high-priority in the previous period and whose priority remains high after the update, nodes that were low-priority in the previous period and whose priority becomes high after the update, and high-priority nodes that are newly connected in the (t-1)-th protocol frame. If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M, then a fixed time slot is allocated to each high-priority node, and the contention probability of each high-priority node in the contention time slot is set to 80%; then proceed to step four. If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step four. Step 4: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception. If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to steps four and five; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to steps four and six. If there is no high-priority node that meets condition (1), then proceed directly to step four and seven. Steps 4 and 5: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80%, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame. Then, randomly select 0.9M nodes from the remaining high-priority nodes, and assign a fixed time slot to each selected high-priority node. The contention probability of each selected high-priority node in the contention time slot is set to 80%. Move each high-priority node that was not selected to the contention time slot, and set the contention probability of each high-priority node that was not selected in the contention time slot to 80%. Then proceed to step four eight; Step 46: Randomly select N-0.9M nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%; Then proceed to step four eight; Step 47: Randomly select 0.9M nodes from all high-priority nodes, and assign a fixed time slot to each selected high-priority node. Set the contention probability of each selected high-priority node within the contention time slot to 80%. Move each unselected high-priority node to a contention time slot, and set the contention probability of each unselected high-priority node within the contention time slot to 80%. Then proceed to step four eight; Step 48: Assign low-priority nodes in the t-th protocol frame to contention slots, and set the contention probability of each low-priority node in the contention slot to 20%. Step 5: Determine the window positions of fixed time slots and contention time slots based on the priority of historical access nodes and the priority of new nodes accessing within the (t-1)th protocol frame. All nodes participate in time slot contention according to the allocated contention probability within the contention time slot. Service data is sent and received only after successful contention. After all time slots of the t-th protocol frame have ended, let t = t + 1, and return to step three.

2. The adaptive unmanned cluster MAC layer hybrid networking method according to claim 1, characterized in that, The method uses a network controller to broadcast in real time the window position information of the fixed time slots and contention time slots within the current protocol frame of the MAC layer.

3. The adaptive unmanned cluster MAC layer hybrid networking method according to claim 2, characterized in that, The new node obtains the contention slot window position based on the information broadcast by the network controller, and then randomly selects a contention slot within the contention slot window to send an access request message; The access request message includes the node ID, the estimated cache queue length, the estimated data packet latency, and the estimated packet loss rate.

4. The adaptive unmanned cluster MAC layer hybrid networking method according to claim 1, characterized in that, The specific process of step five is as follows: Step 51: Determine if there are any nodes that have not communicated in the (t-3)th, (t-2)th, and (t-1)th protocol frames; If a node fails to communicate in the (t-3), (t-2), and (t-1)th protocol frames, the node exits the network from the contention window, and step 5.2 is then executed for the remaining nodes. If no node has communicated in the (t-3), (t-2), and (t-1)th protocol frames, then proceed directly to step 5.

2. Step 5.2: Count the number N of high-priority nodes in the t-th protocol frame, where the high-priority nodes in the t-th protocol frame include historically accessed high-priority nodes and newly accessed high-priority nodes in the (t-1)-th protocol frame. If the number of high-priority nodes N in the t-th protocol frame is less than or equal to 0.9M, then a fixed time slot is allocated to each high-priority node, and the contention probability of each high-priority node in the contention time slot is set to 80%; then proceed to step five and seven. If the number N of high-priority nodes in the t-th protocol frame is greater than 0.9M, then proceed to step five three. Step 53: Determine whether there is a high-priority node that satisfies condition (1) among the high-priority nodes in the t-th protocol frame. Specifically, condition (1) is: a high-priority node that has been allocated a fixed time slot in the previous protocol frame and has not performed service transmission and reception. If there are high-priority nodes that satisfy condition (1), then when the number of high-priority nodes that satisfy condition (1) is less than or equal to N-0.9M, proceed to step five four; when the number of high-priority nodes that satisfy condition (1) is greater than N-0.9M, proceed to step five five. If there is no high-priority node that meets condition (1), proceed directly to steps five and six. Step 54: Release the fixed time slot resources of all high-priority nodes that meet condition (1), transfer all high-priority nodes that meet condition (1) to the contention time slot and set the contention probability to 80% for all of them, and then remove all high-priority nodes that meet condition (1) from the N high-priority nodes in the t-th protocol frame. Then, randomly select 0.9M nodes from the remaining high-priority nodes, and assign a fixed time slot to each selected high-priority node. The contention probability of each selected high-priority node within the contention time slot is set to 80%. Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node within the contention time slot to 80%. Then proceed to step five or seven; Step 5: Randomly select N-0.9M high-priority nodes from all high-priority nodes that meet condition (1), release the fixed time slot resources of the selected high-priority nodes, transfer the selected high-priority nodes to the contention time slot and set the contention probability to 80%, then allocate a fixed time slot to each of the remaining high-priority nodes, and set the contention probability of the remaining high-priority nodes in the contention time slot to 80%; Then proceed to step five or seven; Steps 5 and 6: Randomly select 0.9M nodes from all high-priority nodes, and assign a fixed time slot to each selected high-priority node. Set the contention probability of each selected high-priority node in the contention time slot to 80%. Move each unselected high-priority node to the contention time slot, and set the contention probability of each unselected high-priority node in the contention time slot to 80%. Then proceed to step five or seven; Step 57: Assign the low-priority nodes in the t-th protocol frame to the contention slot, and set the contention probability of each low-priority node in the contention slot to 20%.

5. The adaptive unmanned cluster MAC layer hybrid networking method according to claim 1, characterized in that, When a node conflict occurs within the competition time slot, the high-priority node continues to participate in the time slot competition in the next competition time slot, while the low-priority node goes back to participate in the time slot competition after 5 competition time slots.

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