Underwater hybrid network and multiple access method and device thereof, and storage medium

Abstract

The invention relates to an underwater hybrid network and a multiple access method and device thereof, and a storage medium, and is suitable for an underwater acoustic network, the underwater acoustic network comprises a fixed node and a mobile node, the method comprises the following steps: the fixed node divides a time axis into a superframe structure, the superframe structure comprises a reservation stage and a data transmission stage, the reservation stage is composed of a plurality of micro time slots, and the data transmission stage is composed of a plurality of data time slots; the mobile node sends a reservation control packet to the fixed node in the target micro time slot, and the reservation control packet comprises real-time depth information and position information of the node; the fixed node carries out data time slot distribution on the mobile node based on a constructed three-dimensional node topological graph, and the three-dimensional node topological graph is constructed based on real-time depth information and position information; the mobile node sends a data packet in the allocated target data time slot by adopting a preset data transmission mechanism; compared with the prior art, the technical scheme of the invention can improve the communication efficiency and reliability of the underwater hybrid network.

Description

Technical Field

[0001] The present application relates to the technical field of underwater network communications, and in particular to an underwater hybrid network and its multiple access method, device and storage medium. Background Art

[0002] Multiple access technology for underwater hybrid networks is a key foundation for achieving efficient communication in underwater three-dimensional security systems. Traditional underwater networks are limited by the characteristics of underwater acoustic channels and suffer from inherent challenges such as low available bandwidth, long propagation delays, and high bit error rates.

[0003] Existing access methods mainly use fixed allocation or random competition mechanisms. However, the fixed time slot allocation method cannot adapt to node mobility, resulting in low resource utilization. The random competition mechanism has a high collision rate in long-delay underwater acoustic environments and limited system throughput. These problems seriously restrict the communication efficiency and reliability of underwater hybrid networks.

[0004] Therefore, how to adapt to the characteristics of strong mobility and dynamic topology changes of underwater nodes and improve the communication efficiency and reliability of underwater hybrid networks is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The present application provides an underwater hybrid network and its multiple access method, device and storage medium, which improve the communication efficiency and reliability of the underwater hybrid network.

[0006] In the first aspect, the present application provides a multiple access method for an underwater hybrid network, wherein the underwater hybrid network includes fixed nodes and mobile nodes, and the multiple access method includes: the fixed node divides the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of several micro-time slots, and the data transmission phase is composed of several data time slots; the mobile node sends a reservation control packet to the fixed node in the target micro-time slot, wherein the reservation control packet includes the real-time depth information and location information of the node; the fixed node allocates data time slots to the mobile node based on a constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information; the mobile node uses a preset data transmission mechanism to send data packets within the allocated target data time slot.

[0007] In a possible implementation, before the mobile node sends a reservation control packet to the fixed node during the reservation phase, the process further includes: the fixed node performing positioning processing on the mobile node to obtain location information, and sending the location information to the mobile node so that the mobile node receives the location information.

[0008] In one possible implementation, the fixed node performs positioning processing on the mobile node to obtain location information, including: sending an inquiry pulse signal to the mobile node, receiving a response pulse signal returned by the mobile node based on an ultra-short baseline array installed on the fixed node, and recording an arrival timestamp and a signal phase; calculating a time delay difference based on the arrival timestamp; and calculating a phase difference based on the signal phase; resolving a horizontal azimuth and an elevation angle of the mobile node based on the time delay difference and the phase difference; calculating an acoustic propagation time based on the arrival timestamp; and calculating a slant distance between the mobile node and the fixed node based on the acoustic propagation time; calculating relative coordinates of the mobile node based on the horizontal azimuth, the elevation angle, and the slant distance, converting the relative coordinates into geodetic coordinates, and using the geodetic coordinates as the location information of the mobile node.

[0009] In one possible implementation, the mobile node uses a preset data transmission mechanism to send data packets within the allocated target data time slot, including: segmenting the data packets to be sent to obtain multiple original data packets; constructing a multidimensional random coefficient vector, and performing linear combination coding on the multiple original data packets based on the multidimensional random coefficient vector to obtain a random linear combination coding packet; encapsulating the multidimensional random coefficient vector and the random linear combination coding packet to obtain a random linear coding frame; and sending the random linear coding frame to a relay node within the allocated target data time slot, so that after receiving the random linear coding frames from multiple different sources, the relay node performs coding and superposition processing on the random linear coding frames from multiple different sources to obtain a superposition coding frame, and sends the superposition coding frame to a target gateway node for decoding processing.

[0010] In one possible implementation, the mobile node sends a reservation control packet to the fixed node in a target micro-time slot, specifically including: the mobile node listens to a synchronization beacon sent by the fixed node, wherein the synchronization beacon includes superframe structure boundary information; if the synchronization beacon is listened to, the local clock is synchronized, and according to the superframe structure boundary information, a target micro-time slot is randomly selected, and a reservation control packet is sent to the fixed node within the target micro-time slot.

[0011] In one possible implementation, the process of constructing the three-dimensional node topology map includes: obtaining the real-time depth information and location information of the mobile node based on the reservation control packet, and obtaining the static depth information and static location information of the fixed node; vertically stratifying the network into several virtual layers according to preset depth intervals, and dynamically assigning the mobile node and the fixed node to the target virtual layer according to the real-time depth information and the static depth information; calculating the first depth difference between the nodes in the same layer in each target virtual layer, and based on the first depth difference, clustering the nodes in the same layer in each target virtual layer; calculating the second depth difference between each adjacent target virtual layer, if the second depth difference is greater than the preset inter-layer depth difference, setting a relay node between the current adjacent target virtual layers, and performing cross-layer connection on the current adjacent target virtual layers based on the relay node; if the second depth difference is not greater than the preset inter-layer depth difference, directly performing cross-layer connection on the current adjacent target virtual layers to obtain a three-dimensional node topology map.

[0012] In one possible implementation, the fixed node allocates data time slots to the mobile nodes based on the constructed three-dimensional node topology map, including: the fixed node aggregates the target mobile nodes corresponding to the successfully received reservation control packets to obtain a mobile node list, and sorts the mobile node list based on the data priority and node remaining energy in each aggregated preset control packet to obtain a mobile node sorting list; based on the three-dimensional node topology map, obtains the target cluster corresponding to each target mobile node in the mobile node sorting list, allocates adjacent data time slots to the target mobile nodes in the same cluster, generates a data time slot allocation table and broadcasts it to the entire network.

[0013] In the second aspect, the present application provides an underwater hybrid network, comprising: fixed nodes and mobile nodes: the fixed nodes are used to divide the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of several micro-time slots, and the data transmission phase is composed of several data time slots; the mobile nodes are used to send reservation control packets to the fixed nodes in the target micro-time slots, wherein the reservation control packets include the real-time depth information and location information of the nodes; the fixed nodes are used to allocate data time slots to the mobile nodes based on a constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information; the mobile nodes are used to send data packets using a preset data transmission mechanism within the allocated target data time slots.

[0014] In a third aspect, an embodiment of the present application further provides a computer device, which includes a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the above method when executing the computer program.

[0015] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium, which stores a computer program. The computer program, when executed by a processor, can implement the above method.

[0016] The embodiments of the present application provide a method, which has the following advantages compared with the prior art.

[0017] The method divides a time axis into a superframe structure by the fixed node, wherein the superframe structure comprises a reservation stage and a data transmission stage, wherein the reservation stage is composed of a plurality of micro-slots, and the data transmission stage is composed of a plurality of data slots; the mobile node sends a reservation control packet to the fixed node in a target micro-slot, wherein the reservation control packet comprises real-time depth information and position information of the node; the fixed node allocates data slots to the mobile node based on a constructed three-dimensional node topology graph, wherein the three-dimensional node topology graph is constructed based on the real-time depth information and the position information; the mobile node sends a data packet in a target data slot allocated by the fixed node using a preset data transmission mechanism; compared with the prior art, in the technical solution of the present application, the fixed node divides the time axis into a superframe structure comprising a reservation stage and a transmission stage, collects reservation control packets of the mobile node through the micro-slots, and dynamically allocates data slots to the mobile node based on the constructed three-dimensional node topology graph, thereby effectively solving the problems of low underwater network mobility management and resource utilization, and improving the communication efficiency and reliability of the underwater hybrid network. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments consistent with the present application and, together with the description, further serve to explain the principles of the application.

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0020] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and are not construed to limit the embodiments, and elements having the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings in the drawings do not constitute a proportional limitation.

[0021] Figure 1 is a flowchart of an embodiment of a multi-access method of an underwater hybrid network provided by the present application;

[0022] Figure 2This is a schematic structural diagram of an embodiment of an underwater hybrid network provided by the present application;

[0023] Figure 3 This is a structural diagram of a computer device provided by this application. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, these are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0026] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0027] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0029] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0030] Example 1, see Figure 1 , Figure 1 This is a flow chart of an embodiment of a multiple access method for an underwater hybrid network provided by the present application. Figure 1 As shown, the underwater hybrid network of the method includes fixed nodes and mobile nodes, and the multiple access method includes steps 101 to 104, which are specifically as follows:

[0031] Step 101: The fixed node divides the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of a number of mini-time slots, and the data transmission phase is composed of a number of data time slots.

[0032] In one embodiment, the fixed node acts as a network coordinator and divides the time axis into periodically repeated superframe structures. Each superframe structure is clearly divided into two phases: a reservation phase and a data transmission phase.

[0033] Specifically, the reservation phase consists of several mini-time slots, which are used for mobile nodes to compete for channel resources and send control information.

[0034] Preferably, the length of each mini-time slot needs to cover the maximum propagation delay of the underwater acoustic channel, which is usually 5-10 seconds, to ensure that the control packets of nodes at different distances can be fully transmitted.

[0035] Specifically, the data transmission phase is composed of a number of data time slots, which are used for reliable transmission of actual business data.

[0036] Preferably, the data time slot length is 20-60 seconds, which meets the large capacity requirements of underwater acoustic communication.

[0037] Since underwater communications face inherent bottlenecks such as low sound speed and long propagation delay, traditional random competitive access methods are prone to serious conflicts due to delay uncertainty. Based on this, in the embodiment of the present application, the time axis is divided into a periodically repeating superframe structure, and each superframe structure is clearly divided into two stages: reservation stage and data transmission stage, forming an orderly access process of first reservation and then transmission. Through time stratification, the complex multiple access problem is decomposed into sub-tasks that can be solved step by step, significantly reducing the channel contention overhead.

[0038] Step 102: The mobile node sends a reservation control packet to the fixed node in a target mini-time slot, wherein the reservation control packet includes the real-time depth information and location information of the node.

[0039] In one embodiment, the fixed node performs positioning processing on the mobile node to obtain location information, and sends the location information to the mobile node so that the mobile node receives the location information.

[0040] In one embodiment, the fixed node performs positioning processing on the mobile node to obtain location information, including: sending an inquiry pulse signal to the mobile node, receiving a response pulse signal returned by the mobile node based on an ultra-short baseline array installed on the fixed node, and recording an arrival timestamp and signal phase; calculating a time delay difference based on the arrival timestamp; and calculating a phase difference based on the signal phase; resolving a horizontal azimuth and an elevation angle of the mobile node based on the time delay difference and the phase difference; calculating a sound propagation time based on the arrival timestamp; and calculating a slant distance between the mobile node and the fixed node based on the sound propagation time; calculating relative coordinates of the mobile node based on the horizontal azimuth, the elevation angle, and the slant distance, converting the relative coordinates into geodetic coordinates, and using the geodetic coordinates as the location information of the mobile node.

[0041] Preferably, the fixed node is a gateway node.

[0042] Specifically, the fixed node first transmits an inquiry pulse signal carrying a unique ID identifier to the mobile node at a fixed frequency of 12kHz, wherein the inquiry pulse signal is 10ms long and is encoded using Barker code, which can increase the signal-to-noise ratio by more than 10dB and effectively resist multipath interference in the underwater acoustic channel.

[0043] Specifically, after receiving the inquiry pulse signal transmitted by the fixed node, the mobile node transmits a response pulse signal of the same frequency band to the fixed node after a fixed delay; wherein the fixed delay time is 20ms, and the fixed delay is used to compensate for the signal processing delay of the mobile node to ensure the consistency of the timestamp measurement.

[0044] Specifically, an ultra-short baseline array is rigidly mounted on the fixed node, wherein the ultra-short baseline array includes four receivers, wherein each receiver is used to independently record the arrival timestamp and signal phase of the received reply pulse signal.

[0045] Specifically, when calculating the delay difference based on the arrival timestamp, the fixed node performs pairwise calculations on the timestamps recorded by the four receivers to obtain the delay difference Δt ij =t i -tj , where t i The arrival timestamp recorded for the i-th receiver, t j The arrival timestamp recorded for the jth receiver.

[0046] Specifically, based on the signal phase, when calculating the phase difference, the fixed node performs pairwise calculations on the timestamps recorded by the four receivers to obtain the phase difference Δφ ij =φ i -φ j , modulo 2π, where φ i is the signal phase recorded by the i-th receiver, φ j The signal phase recorded for the jth receiver.

[0047] Specifically, the horizontal azimuth angle is obtained by calculating the horizontal delay difference of the horizontal receiver and substituting the horizontal delay difference into a preset horizontal azimuth angle calculation formula. The preset horizontal azimuth angle calculation formula is as follows:

[0048]

[0049] Where θ is the horizontal azimuth, c is the speed of sound, d1 is the spacing between the lateral receivers, and Δt 12 is the horizontal delay difference.

[0050] Specifically, the vertical delay difference of the vertical receiver is calculated, and the vertical delay difference is substituted into a preset pitch angle calculation formula to obtain the pitch angle; wherein the preset pitch angle calculation formula is as follows:

[0051]

[0052] Where, is the pitch angle, c is the speed of sound, d2 is the vertical receiver spacing, Δt 13 is the vertical delay difference.

[0053] Specifically, when calculating the sound propagation time based on the arrival timestamp, the fixed delay time of the mobile node and the start timestamp of the fixed node sending the inquiry pulse signal are obtained, and the four arrival timestamps, the fixed delay time, and the start timestamp recorded by the four receivers are respectively substituted into the sound propagation time calculation formula to obtain the sound propagation time, wherein the sound propagation time calculation formula is as follows:

[0054]

[0055] Where, T totalis the sound propagation time, t1 is the arrival timestamp recorded by the first receiver, t2 is the arrival timestamp recorded by the second receiver, t3 is the arrival timestamp recorded by the third receiver, t4 is the arrival timestamp recorded by the fourth receiver, T delay is a fixed delay time, T tx The starting timestamp.

[0056] Specifically, the calculated sound propagation time is input into a preset slant distance calculation formula to obtain the slant distance between the mobile node and the fixed node, wherein the slant distance calculation formula is as follows:

[0057]

[0058] Where R is the slant distance, c is the speed of sound, and T total is the sound propagation time.

[0059] Specifically, when calculating the relative coordinates of the mobile node based on the horizontal azimuth angle, the pitch angle, and the slant distance, the horizontal azimuth angle, the pitch angle, and the slant distance are substituted into a relative coordinate calculation formula to obtain the relative coordinates of the mobile node, wherein the relative coordinate calculation formula is as follows:

[0060]

[0061] Specifically, when the relative coordinates are converted into geodetic coordinates and the geodetic coordinates are used as the position information of the mobile node, the relative coordinates are rotated by the attitude matrix M including roll, pitch, and heading to obtain geodetic coordinates; as shown below:

[0062]

[0063] In one embodiment, the mobile node further obtains its own real-time depth information based on a pressure sensor provided on the mobile node.

[0064] In one embodiment, the mobile node constructs a reservation control packet based on the acquired real-time depth information, location information, node ID, number of pending transmissions, data priority, and node remaining energy, wherein the data priority is used to describe the data urgency level.

[0065] In one embodiment, when the mobile node sends a reservation control packet to the fixed node in the target micro-time slot, it listens to the synchronization beacon sent by the fixed node, wherein the synchronization beacon includes superframe structure boundary information; if the synchronization beacon is listened to, the local clock is synchronized, and according to the superframe structure boundary information, the target micro-time slot is randomly selected, and the reservation control packet is sent to the fixed node in the target micro-time slot.

[0066] Specifically, fixed nodes periodically broadcast synchronization beacons, where the synchronization beacons contain superframe structure boundary information, current timestamp and other information. The superframe structure boundary information is marked with the starting time of the current superframe structure and the starting time of the reservation phase and the data transmission phase, ensuring that mobile nodes can maintain clock synchronization even when moving at high speeds; this mechanism solves the clock deviation problem caused by crystal oscillator drift and dynamic Doppler effect of underwater nodes, enables all network nodes to reach a consensus on the time boundaries of the reservation phase and data transmission phase, avoids micro-slots or data slots misalignment caused by clock asynchrony, and is a prerequisite for the normal operation of the entire multiple access mechanism.

[0067] Specifically, since the synchronization beacon carries the current timestamp information of the fixed node, based on this, after the mobile node monitors the synchronization beacon, it can synchronize the local clock through the time difference between sending and receiving to solve the clock deviation problem caused by crystal oscillator drift of the underwater node.

[0068] Specifically, according to the superframe structure boundary information, when randomly selecting the target micro-slot, the number of micro-slots in the reservation phase and their micro-slot lengths are determined by parsing the superframe structure boundary information in the synchronization beacon, a micro-slot time slot map is constructed, and a micro-slot is randomly selected from the micro-slot time slot map as the target micro-slot.

[0069] Preferably, if multiple mobile nodes select the same target micro-time slot, the fixed node identifies the conflicting node through energy detection or decoding failure. At this time, the conflicting node will subsequently receive a retry instruction in the data time slot allocation table sent by the fixed node, and after receiving the retry instruction, adopt a binary backoff algorithm, such as randomly delaying 1-2 superframe structure cycles, and re-compete to reduce the conflict rate.

[0070] Step 103: The fixed node allocates data time slots to the mobile node based on the constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information.

[0071] In one embodiment, the process of constructing the three-dimensional node topology map includes: obtaining the real-time depth information and location information of the mobile node based on the reservation control packet, and obtaining the static depth information and static location information of the fixed node; vertically stratifying the network into several virtual layers according to preset depth intervals, and dynamically assigning the mobile node and the fixed node to the target virtual layer according to the real-time depth information and the static depth information; calculating the first depth difference between the nodes in the same layer in each target virtual layer, and based on the first depth difference, clustering the nodes in the same layer in each target virtual layer; calculating the second depth difference between each adjacent target virtual layer, if the second depth difference is greater than the preset inter-layer depth difference, setting a relay node between the current adjacent target virtual layers, and performing cross-layer connection on the current adjacent target virtual layers based on the relay node; if the second depth difference is not greater than the preset inter-layer depth difference, directly performing cross-layer connection on the current adjacent target virtual layers to obtain a three-dimensional node topology map.

[0072] Specifically, the mobile node sends a reservation control packet to the fixed node during the reservation phase. The reservation control packet includes its own real-time depth information and location information, and uses the real-time depth information and location information to obtain the three-dimensional spatial information of the mobile node; the fixed node periodically broadcasts static location information, including its own static depth information and static location information, and uses the static depth information and static location information as the three-dimensional spatial information of the fixed node; at this time, the routing layer can obtain the three-dimensional spatial information corresponding to the nodes of the entire network through cross-layer interaction, and dynamically construct an initial three-dimensional node topology map based on the three-dimensional spatial information corresponding to the nodes of the entire network, and mark the two-dimensional coordinates and depth coordinates of each node in the initial three-dimensional node topology map to form the spatial basis for routing decisions.

[0073] Specifically, after obtaining the initial three-dimensional node topology map, a preset depth interval is also used to vertically divide the underwater space into several virtual layers. Preferably, the value of the preset depth interval is based on the underwater sound propagation characteristics, such as 100 meters. This is because the sound ray refraction loss corresponding to a 100-meter depth difference increases by approximately 15%, and cross-layer communication needs to be reduced through layered optimization.

[0074] Specifically, the mobile node belongs to the corresponding target virtual layer according to its corresponding real-time depth information; and the fixed node belongs to the corresponding target virtual layer according to the static depth information.

[0075] Specifically, a first depth difference between nodes in the same layer in the same target virtual layer is calculated. If the first depth difference is not greater than a preset depth threshold, the nodes in the same layer are classified into the same cluster; otherwise, the nodes in the same layer are considered not to be in the same cluster.

[0076] Preferably, after the nodes in the same layer are divided into the same cluster, fixed nodes are preferably selected as cluster heads due to their stable location and sufficient power supply. If there is no fixed node in the same cluster, the mobile node with the highest remaining energy and the best link quality is selected as the temporary cluster head.

[0077] Specifically, when the second depth difference between adjacent target virtual layers is greater than the preset inter-layer depth difference, a relay node is set between the layers as a cross-layer bridge; for example, in areas with sudden depth changes, such as seabed cliffs, dedicated relay nodes are deployed to connect adjacent layer clusters to reduce the bending loss of the sound propagation path by minimizing the inter-layer depth difference; if the second depth difference between adjacent target virtual layers is not greater than the preset inter-layer depth difference, communication is carried out directly through the cross-layer nodes without the need for relays, thereby reducing multi-hop delays.

[0078] Specifically, the real-time depth information and location information in the reservation control packet sent by the mobile node are dynamically updated as the mobile node moves. The update frequency is synchronized with the period of the superframe structure to adapt to the depth changes of the mobile node, and an emergency update is triggered when the depth change rate is greater than 1m / s to ensure the timeliness of the topology; preferably, a global topology reorganization is performed every 5 superframe structures, fragmented clusters are merged or relay positions are adjusted, and a new three-dimensional node topology map is broadcast through a deep routing update packet.

[0079] Specifically, the routing layer can also use the Kalman filtering algorithm to fuse the historical node position and current speed of the mobile node to construct a motion vector model, and predict the future position of the mobile node based on the motion vector model. If the future position is compared with the current position, it is a position that crosses the target virtual layer. The routing layer triggers the topology reconstruction in advance, so that the topology pre-reconstruction is executed several superframe structures earlier than the actual cross-layer to compensate for the long propagation delay of the underwater acoustic channel, ensure that the route has been updated when the mobile node reaches the new target virtual layer, and avoid communication interruption.

[0080] In one embodiment, when the fixed node allocates data time slots to the mobile nodes based on the constructed three-dimensional node topology map, the mobile node list is obtained by summarizing the target mobile nodes corresponding to the successfully received reservation control packets, and the mobile node list is sorted based on the data priority and node remaining energy in each summarized preset control packet to obtain a mobile node sorting list; based on the three-dimensional node topology map, the target cluster corresponding to each target mobile node in the mobile node sorting list is obtained, adjacent data time slots are allocated to the target mobile nodes in the same cluster, and a data time slot allocation table is generated and broadcast to the entire network.

[0081] Specifically, after the reservation phase ends, the fixed node screens and aggregates reservation control packets in non-conflicting mini-time slots, obtains all successfully received reservation control packets, and generates a list of mobile nodes to be scheduled based on the node IDs carried in the reservation control packets.

[0082] Specifically, the mobile node list is sorted in two dimensions based on data priority and node remaining energy. For example, the mobile node list is sorted in descending order according to data priority to ensure that emergency data such as alarms are allocated time slots first; and then the mobile nodes with the same data priority are sorted in ascending order according to the node remaining power so that resources are allocated preferentially to low-power nodes. The resulting mobile node sorting list can solve the problem of premature node failure caused by traditional scheduling without considering the energy status, and extend the network life cycle through energy consumption balancing.

[0083] Specifically, the fixed node clusters the sorted list of mobile nodes according to the cluster affiliation recorded in the three-dimensional node topology diagram, and allocates continuous adjacent data time slots to the nodes in the same cluster, which can reduce the bending loss of the sound propagation path and reduce the interference probability between nodes in the cluster; preferably, protection time slots are inserted between different clusters to avoid signal overlap during cross-cluster transmission; the length of the protection time slot is designed based on the maximum propagation delay of the underwater acoustic channel to ensure timing isolation of long-distance inter-cluster communication.

[0084] Specifically, the fixed node further generates a time slot allocation table based on the allocation result of the data time slot, wherein the time slot allocation table includes a node ID and its corresponding target data time slot.

[0085] Specifically, the fixed node broadcasts the time slot allocation table to the entire network before the data transmission phase begins.

[0086] Preferably, the fixed node also screens and aggregates the reservation control packets within the conflicting micro-time slots, and determines a list of conflicting nodes based on the node ID carried in the reservation control packets within the conflicting micro-time slots, and sends a retry instruction, such as a binary backoff strategy, to each conflicting node in the conflicting node list to reduce the probability of competition in the next superframe structure.

[0087] Preferably, fixed nodes need to continuously monitor the network load and dynamically adjust the number of mini-time slots, such as expanding the capacity to improve efficiency when the collision rate is greater than 20%.

[0088] Step 104: The mobile node sends a data packet using a preset data transmission mechanism within the allocated target data time slot.

[0089] In one embodiment, when the mobile node sends a data packet in the allocated target data slot according to the instructions of the time slot allocation table, the fixed node and the relay node remain silent or switch to the receiving mode in the non-allocated time slot to avoid interference; if the data packet of the mobile node is not fully transmitted in the target data slot, it is necessary to re-initiate the reservation in the subsequent superframe structure.

[0090] In one embodiment, when the mobile node uses a preset data transmission mechanism to send a data packet within an allocated target data time slot, it obtains multiple original data packets by segmenting the data packet to be sent; constructs a multidimensional random coefficient vector, and performs linear combination coding on the multiple original data packets based on the multidimensional random coefficient vector to obtain a random linear combination coding packet; encapsulates the multidimensional random coefficient vector and the random linear combination coding packet to obtain a random linear coding frame; and sends the random linear coding frame to a relay node within the allocated target data time slot, so that after receiving the random linear coding frames from multiple different sources, the relay node performs coding superposition processing on the random linear coding frames from multiple different sources to obtain a superposition coding frame, and sends the superposition coding frame to a target gateway node for decoding processing.

[0091] Specifically, the mobile node divides the data packet to be transmitted into k original data packets of equal length according to a fixed size, that is, P = [p1, p2, ..., p k ], where each original data packet p i is an information vector with a length of L bytes, such as L=1000 bytes.

[0092] Specifically, based on the number of the divided original data packets, a multi-dimensional random coefficient vector is constructed; when the number of the original data packets is k, a k-dimensional random coefficient vector is generated Among them, g i ∈ finite field GF(2 8 ).

[0093] Specifically, when performing linear combination coding processing on the multiple original data packets based on the multidimensional random coefficient vector, modular addition and modular multiplication processing are performed on the multiple original data packets and the multidimensional random coefficient vector in a finite field to obtain a random linear combination coding packet e j :

[0094]

[0095] Specifically, when encapsulating the multidimensional random coefficient vector and the random linear combination code packet, the multidimensional random coefficient vector is used as the code vector header, and the random linear combination code packet is encapsulated as the code data to obtain a random linear code frame Framej, as shown below:

[0096]

[0097] Specifically, since the communication range of underwater fixed nodes is limited by the sonar range, when mobile nodes patrol to a farther area, they need to access the network through relay nodes; the relay nodes act as springboards to forward data hop by hop to the target gateway node, solving the problem of insufficient single-point coverage.

[0098] Specifically, the relay node receives random linear coding frames from different mobile nodes, such as receiving random linear coding frames from mobile node A at the same time. and random linear coded frames of mobile node B

[0099] Specifically, the relay node also generates a superposition coefficient vector α, β∈GF(2 8 ).

[0100] Specifically, the coding vector headers in the random linear coding frames of multiple different sources are superimposed based on the superposition coefficient vector to obtain the superimposed coding vector As shown below:

[0101]

[0102] Specifically, the coded data in the random linear coding frames of multiple different sources are superimposed based on the superposition coefficient vector to obtain the superimposed coded data e new , as shown below:

[0103] e new =α·e a +β·e b .

[0104] Specifically, based on the superposition coding vector and the superposition coding data, a superposition coding frame is generated.

[0105] Specifically, after the relay node sends the superimposed coded frame to the target gateway node for decoding processing, the target gateway node collects multiple superimposed coded frames and constructs a coefficient matrix G and a data matrix E based on the collected multiple superimposed coded frames, as shown below:

[0106]

[0107] Specifically, the target gateway node further solves the coefficient matrix G and the data matrix E by Gaussian elimination method, such as G=[p1, p2, ..., p k ] T =E; to complete the decoding process of the superimposed coded frame.

[0108] In one embodiment, a random linear network coding algorithm is used to encode all nodes except the source node, and a superposition coding method is used to linearly combine the coding vector and the information vector of the coded data frame. The sparse network coding method to be applied is theoretically derived and verified. Network throughput, network energy consumption and fairness are used as evaluation indicators. The data transmission protocol based on full network coding is compared with the protocol after adopting the sparse network coding algorithm. It is believed that it can reduce the collision probability, increase network throughput and reduce network energy consumption.

[0109] Preferably, in order to solve the problem of unsuccessful decoding caused by the above-mentioned encoding method, a node cooperation mechanism based on encoding perception is also designed; first, the relay node calculates its own utility, and the factors that need to be taken into account include: link throughput, number of data frames and the probability of successful decoding; then the difference between the node utility value and the maximum utility value of the nodes in the network is encoded, the node backoff time is calculated, and a relay node competition mechanism is designed, and based on this, it is decided whether the node is a candidate relay node, effectively solving the collision problem of the node in the encoding and retransmission process, reducing data packet-ACK conflicts, send-receive conflicts and monitoring conflicts; combined with the aforementioned network coding algorithm, a complete underwater network data transmission protocol is formed.

[0110] Specifically, when a relay node calculates its own utility, it collects key parameters and comprehensively calculates the utility value based on the key parameters. The key parameters include counting the proportion of data packets that can participate in network coding in the total cache, monitoring its own remaining battery energy percentage, and calculating the average depth difference with neighboring nodes. When comprehensively calculating the utility value, the higher the proportion, the more points the utility value adds; the greater the remaining battery energy percentage, the more points the utility value adds; the smaller the average depth difference, the more points the utility value adds, and the utility value is recalculated every 5 minutes.

[0111] Specifically, when encoding the difference between the node utility value and the maximum utility value of the nodes in the network, all nodes periodically broadcast beacon packets containing their own node utility values. After receiving the beacon packets from the neighboring nodes, the relay nodes compare and update the known maximum utility values, compare the current node utility value with the network maximum utility value, and calculate the relative difference percentage between the two; if the difference percentage is ≤20%, it is marked as high priority (00); if the difference percentage is between 20% and 50%, it is marked as medium priority (01); if the difference percentage is greater than 50%, it is marked as low priority (10); the relay node randomly selects a specific waiting time within the interval corresponding to its own priority, and starts a countdown clock to prepare to respond to the request.

[0112] Specifically, the source node broadcasts a relay request in designing a relay node competition mechanism and deciding whether the node is a candidate relay node, wherein the relay request contains the required number of encoded packets, and the nodes receiving the request check their qualifications: the matching degree of the cached data packets needs to exceed 50%, and the nodes cannot be the lowest priority, i.e., nodes without a "10" label; the nodes meeting the conditions start a backoff countdown, continuously listen to the channel during the countdown: if they hear other nodes respond, they immediately exit the competition; if the countdown ends without hearing a response, they send a response packet, wherein the response packet includes the number of encoded packets that can be provided and carries the utility value and depth information of the node itself; in the final decision stage of the source node, all candidate nodes send response packets within a predetermined time; the node providing the most encoded packets is preferentially selected; when the number of provided packets is the same, the node with a higher utility value is selected as the candidate relay node; preferably, if no node responds, the request is reinitiated after a doubled time; if multiple nodes respond at the same time, the node that responds first is selected as the candidate relay node.

[0113] In an embodiment, the mobile node also constructs a transmission path based on the three-dimensional node topology graph when sending data packets in the allocated target data time slot using a preset data transmission mechanism.

[0114] Specifically, based on the three-dimensional node topology graph, the three-dimensional space information of each node is obtained, and based on the three-dimensional space information, the loss values of all adjacent nodes in the topology graph are calculated respectively to form a loss matrix; the mobile node first retrieves all neighbor nodes of the target virtual layer in the three-dimensional node topology graph, obtains the target loss values corresponding to all the neighbor nodes based on the loss matrix, and selects the neighbor node with the smallest loss value as the next hop node; if there is no same layer node or the same layer path is unavailable, the absolute values of the depth differences of all cross-layer neighbor nodes are calculated respectively, and the cross-layer neighbor node with the smallest absolute value of the depth difference is selected as the next hop node; if there are multiple candidate cross-layer neighbor nodes with the same absolute value of the depth difference, the horizontal distances of the candidate cross-layer neighbor nodes are calculated respectively, and the candidate cross-layer neighbor node with the smallest horizontal distance is selected as the next hop node; if the next hop node is the target gateway node, a transmission path is generated; if the next hop node is not the target gateway node, the above steps of retrieving all neighbor nodes of the target virtual layer in the three-dimensional node topology graph are performed again with the currently selected next hop node as the starting point, until the next hop node is the target gateway node.

[0115] Specifically, when calculating the loss values of all adjacent nodes in the topology graph, the slant distance can be calculated according to the horizontal distance and the depth difference of two adjacent nodes, and the geometric distance loss based on the slant distance is calculated as the loss value of the adjacent node.

[0116] Preferably, the mobile node also monitors the rate of change of depth in the transmission path in real time, and when a sudden change in depth Ah > 200m is detected in a certain section of the path, an obstacle avoidance process is triggered immediately, and a path that bypasses the area with the sudden change in depth is selected from the backup path library; if the loss of the backup path increases by no more than 15% compared to the original path, the original path is immediately switched; if the loss increases too much, a topology reconstruction process is started

[0117] A plurality of candidate paths are generated, and the three-dimensional path loss corresponding to each of the plurality of candidate paths is calculated, and the candidate path with the minimum three-dimensional path loss is selected as the transmission path.

[0118] Embodiment 2, see Figure 2 , Figure 2 is a flow structure diagram of an embodiment of an underwater hybrid network provided by the present application, as Figure 2 shown, the underwater hybrid network includes fixed nodes 201 and mobile nodes 202, specifically as follows:

[0119] In an embodiment, the fixed nodes 201 and the mobile nodes 202 are in communication connection.

[0120] In an embodiment, the underwater hybrid network further includes a gateway node.

[0121] Specifically, the underwater hybrid network includes at least one gateway node, a plurality of fixed nodes, and a plurality of mobile nodes.

[0122] Specifically, the fixed nodes act as network backbones and location reference anchor points, which are usually pre-deployed in key areas and know their precise positions; the mobile nodes periodically position themselves using the beacons broadcast by the fixed nodes or the gateway nodes on the water surface; the core strategy of data communication is geographic position routing: each node selects a neighbor node that is closer to the target gateway in terms of geographic position or has better link quality as the next hop for packet forwarding, which can be a fixed node, another mobile node, or a dedicated relay node; the mobile nodes dynamically update their position information and broadcast it to ensure the effectiveness of the routing, and the gateway nodes act as convergence points and ultimately receive all data and transmit it back through a water surface link such as a satellite.

[0123] Specifically, the data transmitted between nodes in the underwater hybrid network is mainly divided into two categories: application data and control signaling. Application data is the core target of the network, which is composed of environmental parameters (such as temperature and salinity) collected by fixed nodes, mission data (such as sonar images, water quality sample information) or status reports (location, power) collected by mobile nodes, and eventually flows to the gateway node. Control signaling is the key to maintaining network operation, including neighbor discovery beacons, routing request / response packets, mobile node location updates, link quality detection information, time synchronization signals and network management instructions (such as task allocation and configuration updates).

[0124] In one embodiment, the fixed node 201 is used to divide the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of a number of micro time slots, and the data transmission phase is composed of a number of data time slots.

[0125] In one embodiment, the mobile node 202 is configured to send a reservation control packet to the fixed node in a target mini-time slot, wherein the reservation control packet includes the real-time depth information and location information of the node.

[0126] In one embodiment, the fixed node 201 is configured to allocate data time slots to the mobile node based on a constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information.

[0127] The mobile node 202 is configured to send data packets using a preset data transmission mechanism within the allocated target data time slot.

[0128] In one embodiment, the fixed node 201 is further configured to perform positioning processing on the mobile node to obtain location information, and send the location information to the mobile node so that the mobile node receives the location information.

[0129] In one embodiment, the fixed node 201 is configured to perform positioning processing on the mobile node to obtain location information, including: sending an inquiry pulse signal to the mobile node, receiving a response pulse signal returned by the mobile node based on an ultra-short baseline array installed on the fixed node, and recording an arrival timestamp and signal phase; calculating a time delay difference based on the arrival timestamp; and calculating a phase difference based on the signal phase; resolving a horizontal azimuth and an elevation angle of the mobile node based on the time delay difference and the phase difference; calculating an acoustic propagation time based on the arrival timestamp; and calculating a slant distance between the mobile node and the fixed node based on the acoustic propagation time; calculating relative coordinates of the mobile node based on the horizontal azimuth, the elevation angle, and the slant distance, converting the relative coordinates into geodetic coordinates, and using the geodetic coordinates as the location information of the mobile node.

[0130] In one embodiment, the mobile node 202 is configured to send data packets using a preset data transmission mechanism within an allocated target data time slot, including: segmenting the data packet to be sent to obtain multiple original data packets; constructing a multidimensional random coefficient vector, and performing linear combination coding on the multiple original data packets based on the multidimensional random coefficient vector to obtain a random linear combination coding packet; encapsulating the multidimensional random coefficient vector and the random linear combination coding packet to obtain a random linear coding frame; and sending the random linear coding frame to a relay node within the allocated target data time slot, so that after receiving the random linear coding frames from multiple different sources, the relay node performs coding superposition processing on the random linear coding frames from the multiple different sources to obtain a superposition coding frame, and sends the superposition coding frame to a target gateway node for decoding processing.

[0131] In one embodiment, the mobile node 202 is used to send a reservation control packet to the fixed node in the target micro-time slot, specifically including: monitoring the synchronization beacon sent by the fixed node, wherein the synchronization beacon includes superframe structure boundary information; if the synchronization beacon is monitored, synchronizing the local clock, and randomly selecting a target micro-time slot based on the superframe structure boundary information, and sending a reservation control packet to the fixed node within the target micro-time slot.

[0132] In one embodiment, the process of constructing the three-dimensional node topology map includes: obtaining the real-time depth information and location information of the mobile node based on the reservation control packet, and obtaining the static depth information and static location information of the fixed node; vertically stratifying the network into several virtual layers according to preset depth intervals, and dynamically assigning the mobile node and the fixed node to the target virtual layer according to the real-time depth information and the static depth information; calculating the first depth difference between the nodes in the same layer in each target virtual layer, and based on the first depth difference, clustering the nodes in the same layer in each target virtual layer; calculating the second depth difference between each adjacent target virtual layer, if the second depth difference is greater than the preset inter-layer depth difference, setting a relay node between the current adjacent target virtual layers, and performing cross-layer connection on the current adjacent target virtual layers based on the relay node; if the second depth difference is not greater than the preset inter-layer depth difference, directly performing cross-layer connection on the current adjacent target virtual layers to obtain a three-dimensional node topology map.

[0133] In one embodiment, the fixed node 201 is used to allocate data time slots to the mobile nodes based on the constructed three-dimensional node topology map, including: summarizing the target mobile nodes corresponding to the successfully received reservation control packets to obtain a mobile node list, and sorting the mobile node list based on the data priority and node remaining energy in each preset control packet to obtain a mobile node sorting list; based on the three-dimensional node topology map, obtaining the target cluster corresponding to each target mobile node in the mobile node sorting list, allocating adjacent data time slots to the target mobile nodes in the same cluster, generating a data time slot allocation table and broadcasting it to the entire network.

[0134] The underwater hybrid network can implement the underwater hybrid network multiple access method of the above method embodiment. The options in the above method embodiment are also applicable to this embodiment and will not be described in detail here.

[0135] like Figure 3 As shown, Figure 3 This is a structural diagram of a computer device provided by the present application; it includes a processor 111, a communication interface 112, a memory 113 and a communication bus 114, wherein the processor 111, the communication interface 112, and the memory 113 communicate with each other through the communication bus 114, and the memory 113 is used to store computer programs.

[0136] In one embodiment of the present application, the processor 111 is configured to implement the multiple access method for the underwater hybrid network provided by any one of the aforementioned method embodiments when executing the program stored in the memory 113 .

[0137] Those skilled in the art will appreciate that all or part of the steps in the method of the above-described embodiment can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the steps in the method of the above-described embodiment.

[0138] Therefore, an embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the multiple access method for an underwater hybrid network provided in any of the aforementioned method embodiments are implemented.

[0139] The storage medium is a physical, non-transient storage medium, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a magnetic disk, or an optical disk, etc. Any physical storage medium capable of storing program code can be non-volatile or volatile.

[0140] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0141] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0142] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the spirit and scope of this application. Thus, as long as these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0143] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A multiple access method for an underwater hybrid network, characterized in that: The underwater hybrid network includes fixed nodes and mobile nodes, and the multiple access method includes: The fixed node divides the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of a plurality of mini-time slots, and the data transmission phase is composed of a plurality of data time slots; The mobile node sends a reservation control packet to the fixed node in a target mini-time slot, wherein the reservation control packet includes real-time depth information and location information of the node; The fixed node allocates data time slots to the mobile node based on a constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information; The mobile node transmits a data packet using a preset data transmission mechanism within the allocated target data time slot.

2. The method according to claim 1, wherein Before the mobile node sends the reservation control packet to the fixed node during the reservation phase, the mobile node further includes: The fixed node performs positioning processing on the mobile node to obtain location information, and sends the location information to the mobile node so that the mobile node receives the location information.

3. The method according to claim 1, wherein The fixed node performs positioning processing on the mobile node to obtain location information, including: sending an inquiry pulse signal to the mobile node, receiving a reply pulse signal returned by the mobile node based on an ultra-short baseline array installed on the fixed node, and recording an arrival timestamp and a signal phase; Calculating a time delay difference based on the arrival timestamp; calculating a phase difference based on the signal phase; resolving a horizontal azimuth angle and a pitch angle of the mobile node based on the time delay difference and the phase difference; calculating a sound propagation time based on the arrival timestamp; and calculating a slant range between the mobile node and the fixed node based on the sound propagation time; Based on the horizontal azimuth angle, the pitch angle, and the slant range, the relative coordinates of the mobile node are calculated, the relative coordinates are converted into geodetic coordinates, and the geodetic coordinates are used as the position information of the mobile node.

4. The method according to claim 1, wherein The mobile node sends a data packet using a preset data transmission mechanism within the allocated target data time slot, including: Segment the data packet to be sent to obtain multiple original data packets; constructing a multidimensional random coefficient vector, and performing linear combination coding processing on the plurality of original data packets based on the multidimensional random coefficient vector to obtain a random linear combination coded packet; Encapsulating the multidimensional random coefficient vector and the random linear combination code packet to obtain a random linear code frame; In the allocated target data time slot, the random linearly coded frame is sent to the relay node, so that after receiving the random linearly coded frames from multiple different sources, the relay node performs encoding and superposition processing on the random linearly coded frames from multiple different sources to obtain superposition coded frames, and sends the superposition coded frames to the target gateway node for decoding processing.

5. The method according to claim 1, wherein The mobile node sends a reservation control packet to the fixed node in a target mini-time slot, specifically comprising: The mobile node monitors a synchronization beacon sent by the fixed node, wherein the synchronization beacon includes superframe structure boundary information; If the synchronization beacon is monitored, the local clock is synchronized, and according to the superframe structure boundary information, a target mini-time slot is randomly selected, and a reservation control packet is sent to the fixed node within the target mini-time slot.

6. The method according to claim 1, wherein The process of constructing the three-dimensional node topology graph includes: Acquire the real-time depth information and location information of the mobile node based on the reservation control packet, and acquire the static depth information and static location information of the fixed node; Vertically stratifying the network into a plurality of virtual layers according to preset depth intervals, and dynamically assigning the mobile node and the fixed node to a target virtual layer according to the real-time depth information and the static depth information; Calculating a first depth difference between nodes in the same layer in each target virtual layer, and dividing each node in the same layer in each target virtual layer into the same cluster based on the first depth difference; Calculate the second depth difference between each adjacent target virtual layer. If the second depth difference is greater than the preset inter-layer depth difference, set a relay node between the current adjacent target virtual layers, and perform cross-layer connection on the current adjacent target virtual layers based on the relay node. If the second depth difference is not greater than the preset inter-layer depth difference, directly perform cross-layer connection on the current adjacent target virtual layers to obtain a three-dimensional node topology map.

7. The method according to claim 6, wherein The fixed node allocates data time slots to the mobile node based on the constructed three-dimensional node topology graph, including: The fixed node aggregates the target mobile nodes corresponding to the successfully received reservation control packets to obtain a mobile node list, and sorts the mobile node list based on the data priority and node remaining energy in each aggregated preset control packet to obtain a sorted mobile node list; Based on the three-dimensional node topology graph, a target cluster corresponding to each target mobile node in the mobile node sorting list is obtained, adjacent data time slots are allocated to target mobile nodes in the same cluster, and a data time slot allocation table is generated and broadcasted to the entire network.

8. An underwater hybrid network, characterized in that: include: Fixed nodes and mobile nodes: The fixed node is used to divide the time axis into a superframe structure, wherein the superframe structure includes a reservation phase and a data transmission phase, wherein the reservation phase is composed of a plurality of mini-time slots, and the data transmission phase is composed of a plurality of data time slots; The mobile node is configured to send a reservation control packet to the fixed node in a target mini-time slot, wherein the reservation control packet includes real-time depth information and location information of the node; The fixed node is configured to allocate data time slots to the mobile node based on a constructed three-dimensional node topology map, wherein the three-dimensional node topology map is constructed based on the real-time depth information and the location information; The mobile node is configured to send data packets using a preset data transmission mechanism within the allocated target data time slot.

9. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the computer program can implement the method according to any one of claims 1 to 7.

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