An underwater acoustic network simulation system

Abstract

The present application discloses an underwater acoustic network simulation system, comprising multiple communication nodes, wherein the communication nodes are configured to divide a transmission channel into multiple sub-channels at the physical layer and determine a channel number for each sub-channel; the communication nodes are further configured to determine the channel number of the channel used to send a data packet using a preset frequency division protocol at the MAC layer to obtain a target channel number, match the corresponding target channel based on the target channel number at the physical layer, and send the data packet based on the target channel. In this way, frequency division simulation of underwater acoustic communication can be implemented, thereby adapting to a wider range of test scenarios.

Description

Technical Field

[0001] The present application relates to the technical field of underwater acoustic network simulation, and in particular to an underwater acoustic network simulation system. Background Art

[0002] Underwater acoustic communication is a key technology for wireless information transmission in the ocean, widely used in a variety of fields, including marine environmental monitoring, offshore exploration, assisted navigation, and tsunami warning. With the increasing complexity and diversity of underwater missions, underwater acoustic communication has evolved from point-to-point communication to multi-node networked communication. Therefore, underwater acoustic communication and networking are particularly important for the development and utilization of marine resources. In complex ocean environments, the performance of underwater acoustic communication networks is severely affected by the underwater acoustic channel. The underwater acoustic channel is a complex medium formed by the ocean and its boundaries. Its internal structure and unique upper and lower surfaces can have many different effects on sound waves. Furthermore, the underwater acoustic channel is characterized by large propagation delay, narrow effective bandwidth, limited energy, and severe multipath and Doppler effects. Therefore, research and design of underwater acoustic communication and networking are necessary to improve the transmission rate of underwater acoustic communication while ensuring its reliability and robustness.

[0003] Research on underwater acoustic communication and networking usually requires verification in a real field (lake / sea) test environment. However, field testing is expensive, labor-intensive, and resource-intensive. The time-varying and space-varying characteristics of underwater acoustic channels complicate the setup of sea-based testing experiments. Therefore, simulation experiments have become the primary means of verifying the performance of underwater acoustic communication network research results before actual sea testing. Developing a reliable, stable, and efficient simulation system to provide an accurate, low-cost testing platform for underwater acoustic communication network research is crucial. However, most existing underwater acoustic communication network systems are based on a single channel, making them difficult to adapt to a wider range of test scenarios. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an underwater acoustic network simulation system that can realize frequency division simulation of underwater acoustic communication, thereby adapting to a wider range of test scenarios. The specific solution is as follows:

[0005] An underwater acoustic network simulation system includes multiple communication nodes, wherein:

[0006] The communication node is configured to divide a transmission channel into a plurality of sub-channels at a physical layer, and determine a channel number for each of the sub-channels;

[0007] The communication node is also used to use a preset frequency division protocol at the MAC layer to determine the channel number of the channel used to send the data packet to obtain a target channel number, match the corresponding target channel based on the target channel number at the physical layer, and send the data packet based on the target channel.

[0008] Optionally, the communication node is specifically used to: if the target channel number is the channel number of any of the sub-channels, then match the corresponding sub-channel based on the channel number at the physical layer, and send the data packet based on the sub-channel; if the target channel number is the channel number of the transmission channel, then send the data packet based on the transmission channel using the entire frequency band at the physical layer.

[0009] Optionally, the communication node is specifically configured to: calculate the bandwidth range of each sub-channel at the physical layer based on the communication bandwidth range and the number of channel divisions in the configuration file to divide the transmission channel into multiple sub-channels.

[0010] Optionally, the communication node is further used to determine the communication mode corresponding to the data packet at the MAC layer, and send the data packet using a processing module corresponding to the communication mode at the physical layer, wherein the communication mode is acoustic communication or optical communication.

[0011] Optionally, if the communication node is an underwater glider node, the communication node is further configured to perform zigzag movement using a preset underwater glider movement module.

[0012] Optionally, it is specifically used to use a preset underwater glider movement module to determine its own velocity vector based on a first preset parameter, perform a zigzag motion according to the velocity vector, and use the preset underwater glider movement module to calculate its own moving distance and current position according to the simulation time, and check whether its own position exceeds the preset depth range at a preset period. If it exceeds the preset depth range, the velocity vector is recalculated according to the opening angle parameter.

[0013] Optionally, if the communication node is a wave glider, the communication node is further configured to simulate movement on the sea surface using a preset wave glider movement module.

[0014] Optionally, the communication node is specifically used to use a preset wave glider movement module to determine the initial motion state based on a second preset parameter and move based on a wave model, and calculate the wave height based on the current time, the two-dimensional sea surface coordinates of the node and the wave model, and calculate the three-dimensional coordinates of the node based on the wave height.

[0015] Optionally, if the communication node is an unmanned underwater vehicle, the communication node is further configured to move based on preset motion instructions using a preset unmanned underwater vehicle movement module.

[0016] Optionally, the communication node is specifically used to use a preset unmanned underwater vehicle movement module to read preset motion instructions from a preset text in sequence, and perform linear motion or curved motion based on the preset motion instructions; wherein the preset motion instructions corresponding to the linear motion carry speed, direction and execution information, and the curved motion carries linear velocity, angular velocity, pitch angle and execution time.

[0017] It can be seen that the underwater acoustic network simulation system provided by the present application includes multiple communication nodes, wherein the communication nodes are used to divide the transmission channel into multiple sub-channels at the physical layer and determine the channel number of each sub-channel; the communication nodes are also used to determine the channel number of the channel used to send the data packet using a preset frequency division protocol at the MAC layer to obtain a target channel number, match the corresponding target channel based on the target channel number at the physical layer, and send the data packet based on the target channel. That is, in the present application, any communication node of the underwater acoustic network simulation system divides the transmission channel into multiple sub-channels at the physical layer and determines the channel number of each sub-channel. When communicating with other nodes, the communication nodes use the preset frequency division protocol at the MAC layer to determine the channel number of the channel used to send the data packet to obtain a target channel number, match the corresponding target channel based on the target channel number at the physical layer, and send the data packet based on the target channel. In this way, frequency division simulation of underwater acoustic communication can be achieved, thereby adapting to richer test scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0019] Figure 1 A schematic diagram of an underwater acoustic network simulation system disclosed in this application;

[0020] Figure 2 A specific multi-band communication flow chart disclosed in this application;

[0021] Figure 3 A specific underwater acoustic network simulation system communication diagram disclosed in this application;

[0022] Figure 4 This is a specific multimodal communication flow chart disclosed in this application. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only 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.

[0024] Research on underwater acoustic communication and networking usually needs to be verified in a real field (lake / sea) test environment. However, field testing is expensive, labor- and material-intensive, and the time-varying and space-varying characteristics of underwater acoustic channels make the construction of sea-test experiments complicated. Therefore, it is crucial to develop a reliable, stable, and efficient simulation system to provide an accurate and low-cost testing platform for underwater acoustic communication network research. However, most existing underwater acoustic communication network systems are based on a single channel and are difficult to adapt to richer test scenarios. To this end, the present application provides an underwater acoustic network simulation system that can realize frequency-division simulation of underwater acoustic communications, thereby adapting to richer test scenarios.

[0025] See also Figure 1 As shown, the embodiment of the present application discloses an underwater acoustic network simulation system 10, including multiple communication nodes, wherein:

[0026] The communication node is used to divide the transmission channel into multiple sub-channels at the physical layer and determine the channel number of each sub-channel.

[0027] In a specific embodiment, the communication node is specifically configured to calculate, at the physical layer, the bandwidth range of each subchannel based on the communication bandwidth range and the number of channel divisions in the configuration file, to divide the transmission channel into multiple subchannels. That is, the communication bandwidth range and the number of channel divisions of the transmission channel can be written into the configuration file. Any communication node in the underwater acoustic network simulation system can calculate, at the physical layer, the bandwidth range of each subchannel based on the communication bandwidth range and the number of channel divisions in the configuration file, to divide the transmission channel into multiple subchannels, and mark each subchannel with a channel number.

[0028] The communication node is further configured to determine, at the MAC layer (i.e., Media Access Control), a channel number of a channel used to send a data packet using a preset frequency division protocol to obtain a target channel number, match a corresponding target channel based on the target channel number at the physical layer, and send the data packet based on the target channel.

[0029] In a specific embodiment, the communication node is specifically configured to, if the target channel number is the channel number of any of the sub-channels, match the corresponding sub-channel based on the channel number at the physical layer and send the data packet based on the sub-channel; if the target channel number is the channel number of the transmission channel, then, if the target channel number is the channel number of the transmission channel, send the data packet using the entire frequency band based on the transmission channel at the physical layer. That is, in this embodiment of the present application, the underwater acoustic network simulation system not only retains the full-band communication tag, that is, the channel number of the transmission channel, but also implements frequency division simulation, thereby meeting the simulation of mixed full-band and sub-band communications.

[0030] It can be understood that the embodiment of the present application implements the frequency division selection function at the physical layer. The underwater acoustic network simulation system can divide the bandwidth based on actual needs. The communication bandwidth range and the number of channel divisions are input in the configuration file. Any communication node calculates the bandwidth range of each sub-channel at the physical layer based on these two parameters in the configuration file, and performs channel numbering at the same time. The MAC layer uses a frequency division related protocol. The data packet will be marked with the corresponding channel number, and the channel number matching will be performed at the physical layer. Finally, the data will be sent according to the communication parameters of the matched channel. In addition, considering that there are mixed communications of full-band and sub-band in practice, in the embodiment of the present application, the underwater acoustic network simulation system retains the full-band communication mark in the frequency division physical layer module, and the node can select the corresponding frequency band based on the MAC protocol result. See. Figure 2 As shown, Figure 2 This is a specific multi-band communication flow chart disclosed in an embodiment of the present application.

[0031] Furthermore, the protocol stack in the underwater acoustic network simulation system provided in the embodiment of the present application includes a channel module, a physical layer, a MAC layer, a network layer, a transport layer, and an application layer. In addition, a cross-layer shared space is used in the network architecture, and each protocol layer in the protocol stack obtains shared information, such as modem configuration, SNR (i.e., signal-to-noise ratio), time synchronization information, node location, etc., through the cross-layer shared space. In this way, the use of a cross-layer shared space makes it easier for each protocol layer in the protocol stack to obtain shared information.

[0032] In addition, in the underwater acoustic network simulation system, the first communication node acts as a sending node and the second communication node acts as a receiving node. The first communication node creates a data packet at the application layer, sends the data packet to the transport layer, sub-packets the data packet at the transport layer, and then sends it to the network layer. The network layer searches for the next hop node and marks it according to the routing protocol. After the MAC layer receives the data packet from the network layer, it makes a communication request to the second communication node according to the MAC protocol. After receiving the reply, it sends the data packet to the physical layer. The data information is modulated at the physical layer and sent to the next hop node through the channel. The second communication node determines whether it is the destination node at the network layer. If it is the destination node, it sends the data packet to the upper layer. If not, it continues to forward the information to the MAC layer according to the routing table.

[0033] For example, see Figure 3 As shown, Figure 3 The present invention discloses a specific communication diagram of an underwater acoustic network simulation system. Assume that node 1 is a sending node and node 2 is a receiving node. Node 1 creates a data packet at the application layer, and the packet header includes a sending address and a destination address, and sends the data packet to the transport layer. The data packet is divided into packets at the transport layer, and then the data packet is sent to the network layer. The network layer searches for the next hop node and marks it according to the routing protocol. After the data link layer, i.e., the MAC layer, receives the data packet from the network layer, it applies for communication according to the MAC protocol, and sends the data packet to the physical layer after receiving the reply. The data information is modulated at the physical layer and sent to the next hop node through the channel. The node that receives the information determines whether it is the destination node at the network layer. If it is the destination node, it sends the data packet to the upper layer. If not, it continues to forward the information to the MAC layer according to the routing table. Node 2 sends an ACK confirmation packet to node 1 at the MAC layer to inform node 1 that the data packet has been received correctly. If node 1 does not receive the ACK confirmation packet within a period of time, it resends the data to node 2.

[0034] Furthermore, in an embodiment of the present application, the communication node is further configured to determine, at the MAC layer, the communication mode corresponding to the data packet, and to transmit the data packet using a processing module corresponding to the communication mode at the physical layer, wherein the communication mode is acoustic communication or optical communication. In a specific embodiment, the communication mode corresponding to the data packet can be determined at the MAC layer, a communication mode tag can be generated, and the data packet can be transmitted at the physical layer using a processing module corresponding to the communication mode tag.

[0035] It should be pointed out that the existing underwater acoustic network simulation system only considers the single mode simulation of acoustic communication, while the underwater acoustic network simulation system provided in the embodiment of the present application supports multi-modal communication simulation of acoustic and optical fusion. Acoustic communication can achieve medium and long distance communication underwater, but the rate is low and the channel has strong spatiotemporal variability. Optical communication can achieve high-speed underwater communication, but the communication distance is short. Therefore, a multimodal communication technology is proposed to combine the advantages of acoustic communication and optical communication to jointly improve the performance of underwater communication networks. In the implementation of this application, the underwater acoustic network simulation system includes two information processing modules, acoustic communication and optical communication. Based on the relevant multimodal protocol, the MAC layer determines which communication mode the data packet uses and marks it. The physical layer identifies the communication mode through the mark and sends the data packet to the corresponding processing module. Data is sent according to the acoustic communication or optical communication parameters, see. Figure 4 As shown, Figure 4 A specific multimodal communication flow chart provided in an embodiment of the present application.

[0036] Furthermore, in the underwater acoustic network simulation system provided in the embodiment of the present application, if the communication node is an underwater glider node, the communication node is also used to perform zigzag movement using a preset underwater glider movement module.

[0037] In a specific embodiment, the communication node is configured to use a preset underwater glider movement module to determine its own velocity vector based on first preset parameters, perform zigzag motion based on the velocity vector, calculate its own movement distance and current position based on simulation time using the preset underwater glider movement module, and check whether its own position exceeds a preset depth range at a preset period. If the position exceeds the preset depth range, the velocity vector is recalculated based on the opening angle parameter. The first preset parameters may include relevant parameters such as velocity, gliding depth range, and opening angle.

[0038] Furthermore, in the underwater acoustic network simulation system provided in an embodiment of the present application, if the communication node is a wave glider, the communication node is also used to simulate movement on the sea surface using a preset wave glider movement module.

[0039] In a specific embodiment, the communication node is specifically used to use a preset wave glider movement module to determine the initial motion state based on a second preset parameter and move based on a wave model, and calculate the wave height based on the current time, the two-dimensional sea surface coordinates of the node and the wave model, and calculate the three-dimensional coordinates of the node based on the wave height.

[0040] Furthermore, in the underwater acoustic network simulation system provided in the embodiment of the present application, if the communication node is an unmanned underwater vehicle, the communication node is also used to move based on preset motion instructions using a preset unmanned underwater vehicle movement module.

[0041] In a specific embodiment, the communication node is specifically configured to utilize a preset UUV movement module to sequentially read preset motion instructions from a preset text, and to perform linear or curved motion based on the preset motion instructions. The preset motion instructions corresponding to the linear motion carry speed, direction, and execution information, while the curved motion carries linear velocity, angular velocity, pitch angle, and execution time. Furthermore, the preset UUV movement module is also configured to save the parameters of the current UUV execution instruction, as well as the UUV's location and time information. The next time the system acquires the UUV's latest location information, the UUV movement module calculates the current UUV's reached location based on the time difference and saves the current state. The UUV movement module automatically reads the next motion instruction upon completion of the current instruction and updates its own motion mode. If all instructions have been executed, the UUV remains stationary and on standby.

[0042] That is, the underwater acoustic network simulation system provided by the embodiment of the present application establishes a submersible movement module based on the movement characteristics of several types of mobile nodes.

[0043] The underwater glider (UG) achieves heave and sinking through buoyancy adjustment, and uses the hydrodynamic force of the fixed wing to achieve underwater zigzag gliding motion. The simulation system creates a new UG Mobility module (Underwater Glider Mobility Module) to simulate its movement trajectory. Relevant parameters such as speed, gliding depth range, and opening angle are preset. When the simulation starts, the UG Mobility module determines its own velocity vector based on the speed value and direction of the glider, and calculates its own movement distance and current position according to the simulation time. The UG Mobility module checks whether the coordinates of the node exceed the preset range at fixed intervals. If the node runs out of the set depth range, the model will recalculate the velocity vector after the node based on the opening angle parameter to ensure that the node moves in a zigzag manner within the specified depth range.

[0044] A wave glider (WG) operates on a similar principle to an underwater glider, leveraging the rise and fall of waves to achieve surface motion. A new WG Mobility module is created in the simulation system to simulate its motion trajectory. The WG's initial motion state is initialized with a preset speed and direction. Upon simulation start, the WG Mobility module calculates the node's position based on its 2D sea surface coordinates and the wave model WaveUtil. The wave model calculates the wave height at a specified plane coordinate based on the system's current time. The wave glider then determines its 3D coordinates based on the wave height.

[0045] An unmanned underwater vehicle (UUV) is an active vehicle that can execute tasks according to pre-set instructions. A new WG Mobility module is created in the simulation system to simulate its movement trajectory. The UV Mobility module pre-reads motion instructions stored in a text file and executes them sequentially. Instructions can select two motion modes: linear and curved. Linear motion instructions specify the UUV's subsequent speed, direction, and execution time; curved motion instructions specify the UUV's subsequent linear velocity, angular velocity, pitch angle, and execution time. The UV Mobility module saves the parameters of the current instruction executed by the UUV, as well as the UUV's position and time information. The next time the system requests the UUV's latest position information, the UV Mobility module calculates the UUV's current position based on the time difference and saves the current state. When the current instruction completes execution, the UV Mobility module automatically reads the next motion instruction and updates its own motion mode. If all instructions have been executed, the UUV remains stationary and waits for further instructions.

[0046] It should be pointed out that most existing underwater acoustic communication network systems are based on single-channel, single-mode, and fixed-node communication simulations, and are unable to accurately simulate frequency division multiplexing algorithms, multimodal communications, and formation mobile cluster networking. The embodiment of the present application proposes an underwater acoustic network simulation system based on NS3 (a discrete event simulator), which, while realizing the basic simulation functions of the underwater acoustic communication network, provides a frequency division selection physical layer module, a multimodal communication module, and a variety of mobile models. That is, the underwater acoustic network simulation system of the embodiment of the present application adds frequency division communication simulation functions, multimodal communication simulation functions, and various types of submarine movement simulations, thereby providing underwater communication network simulations with more complex scenarios and more advanced technologies to adapt to richer test scenarios. Reduce experimental costs and improve verification efficiency.

[0047] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. The steps of the method or algorithm described in conjunction with the embodiments disclosed herein can be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module can be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0048] The above is a detailed introduction to an underwater acoustic network simulation system provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for general technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An underwater acoustic network simulation system, characterized in that: It includes multiple communication nodes, among which, The communication node is configured to divide a transmission channel into a plurality of sub-channels at a physical layer, and determine a channel number for each of the sub-channels; The communication node is further configured to determine, at the MAC layer, using a preset frequency division protocol, a channel number of a channel used to transmit a data packet to obtain a target channel number, match a corresponding target channel based on the target channel number at the physical layer, and transmit the data packet based on the target channel; if the target channel number is the channel number of any subchannel, match the corresponding subchannel; if the target channel number is the channel number of a transmission channel, transmit the data packet using the entire frequency band based on the transmission channel; The protocol stack in the underwater acoustic network simulation system includes the channel module, physical layer, MAC layer, network layer, transport layer, and application layer. The network architecture adopts a cross-layer shared space. Each protocol layer in the protocol stack obtains shared information through the cross-layer shared space, including modem configuration, SNR, time synchronization information, and node location. The communication node is further configured to determine the communication mode corresponding to the data packet at the MAC layer based on a relevant multimodal protocol, generate a communication mode tag, and send the data packet using a processing module corresponding to the communication mode tag at the physical layer. The communication mode is acoustic communication or optical communication. The underwater acoustic network simulation system includes two information processing modules, acoustic communication and optical communication. If the communication node is an underwater glider node, the communication node is also used to perform zigzag movement using a preset underwater glider movement module; if the communication node is a wave glider, the communication node is also used to simulate movement on the sea surface using a preset wave glider movement module; if the communication node is an unmanned underwater vehicle, the communication node is also used to move based on preset movement instructions using a preset unmanned underwater vehicle movement module.

2. The underwater acoustic network simulation system according to claim 1, characterized in that: The communication node is specifically configured to calculate the bandwidth range of each sub-channel at the physical layer based on the communication bandwidth range and the number of channel divisions in the configuration file to divide the transmission channel into multiple sub-channels.

3. The underwater acoustic network simulation system according to claim 1, characterized in that: If the communication node is an underwater glider node, the communication node is specifically used to use a preset underwater glider movement module to determine its own velocity vector based on a first preset parameter, perform a zigzag motion according to the velocity vector, and use the preset underwater glider movement module to calculate its own moving distance and current position according to the simulation time, and check whether its own position exceeds the preset depth range at a preset period. If it exceeds the preset depth range, the velocity vector is recalculated according to the opening angle parameter.

4. The underwater acoustic network simulation system according to claim 1, characterized in that: If the communication node is a wave glider, the communication node is specifically used to use a preset wave glider movement module to determine the initial motion state based on the second preset parameters and move based on the wave model, and calculate the wave height according to the current time, the two-dimensional sea surface coordinates of the node and the wave model, and calculate the three-dimensional coordinates of the node according to the wave height.

5. The underwater acoustic network simulation system according to claim 1, characterized in that: If the communication node is an unmanned underwater vehicle, the communication node is specifically used to use a preset unmanned underwater vehicle movement module to read preset motion instructions from a preset text in sequence, and perform linear motion or curved motion based on the preset motion instructions; wherein the preset motion instructions corresponding to the linear motion carry speed, direction and execution information, and the curved motion carries linear velocity, angular velocity, pitch angle and execution time.

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