Wireless sensing system based on sound wave communication technology and communication method

Abstract

The invention discloses a wireless sensing system based on a sound wave communication technology and a communication method, the wireless sensing system comprises a plurality of measuring nodes and sub-measuring systems, the measuring nodes are arranged on a solid sound transmission medium of a measured device, the measuring nodes are connected through sound wave communication, and the sub-measuring nodes are in communication connection with the measuring system; the sub-measurement system is a superior sub-measurement system and / or a parallel sub-measurement system, the measurement node comprises a CPU module, a power management module, a sensor measurement module, a sound wave communication module and a sensor, and the CPU module is connected with the power management module, the sensor measurement module and the sound wave communication module. One end of the sensor is connected with the sensor measuring module, and the other end of the sensor is arranged on the solid sound transmission medium of the measured device. By introducing the sound wave communication technology, the problem of information interaction between the measurement nodes is effectively solved.

Description

Technical Field

[0001] The invention relates to a wireless sensor network technology of a dam safety monitoring automation system, and in particular to a wireless sensor system and a communication method based on acoustic wave communication technology. Background Art

[0002] Dams are the main hydraulic structures of water conservancy hubs. The operating conditions are very complex and there are many uncertain factors. At the same time, the safe operation of dams is related to the safety of life and property of the people upstream and downstream and the protection of the ecological environment. Once a dam fails, it will cause huge losses to the life and property of the people downstream. Although a certain safety factor is adopted in the design stage to enable the dam to bear various load combinations, it is impossible to foresee all adverse changes in the design and the construction quality cannot be perfect. The dam is still likely to fail during use. A large number of facts have also proved that there are signs of dam damage beforehand. Systematic observation of dams is the most effective means to timely grasp the changes in the state of the reservoir. Therefore, dam safety monitoring has become an indispensable work item in the daily operation of dams.

[0003] Dam safety monitoring involves many monitoring projects, which can be divided into internal monitoring and external monitoring. Among them, internal monitoring generally needs to be realized through various sensors buried in the dam body. Due to the structural characteristics of the dam body, it generally does not have line-of-sight conditions. Traditional internal measurement methods generally use manual reading or distributed measurement to realize data collection of sensors. Distributed measurement generally uses the method of extending the wire to relatively concentrate some sensors that are close to each other (generally not more than 100m) into several data acquisition devices, and then network the data acquisition devices through wired communication methods (such as optical fiber communication, RS485 serial bus, etc.), and finally realize the data collection function of all internal sensors. Although this method can basically realize the automatic data collection function, the construction difficulty and engineering volume are very large, the construction cost is high, and the overall technical level is also low. With the rapid development of WSN technology in other fields, the wireless technology upgrade of the existing dam safety monitoring system is becoming an urgent new demand. Although the current wireless sensor network technology (WSN) is very mature and has been widely used in engineering, it cannot be applied to special fields such as dam safety monitoring (especially corridor environment) because it uses electromagnetic wave wireless communication and cannot solve the line-of-sight obstruction problem.

[0004] Acoustic wave communication is a relatively advantageous wireless communication networking solution in this application scenario. The present invention relates to a method and device for realizing a wireless sensing system based on acoustic wave communication technology. The device is composed of a plurality of measurement nodes. Furthermore, each measurement node is composed of a CPU module, a power management module, a sensor measurement module, an acoustic wave communication module, a network communication interface (optional), and the like. Among them, the acoustic wave communication module is the core module of the device. In an environment with severe line-of-sight obstruction such as a corridor environment, the acoustic wave communication is replaced by electromagnetic wave communication to realize the communication and networking functions between the measurement nodes using acoustic waves as the transmission medium. The network communication interface (optional) provided in the measurement node is mainly used for extended applications with other network devices, and can also provide traditional electromagnetic wave communication networking functions for application scenarios with line-of-sight communication conditions, providing flexible and diverse communication networking means for WSN. Summary of the invention

[0005] Purpose of the invention: In view of the practical difficulty that the existing wireless sensor network system based on electromagnetic wave communication networking technology cannot be operated in engineering under the condition that the electromagnetic wave communication path is constrained, the present invention provides a wireless sensor system based on acoustic wave communication technology.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A wireless sensor system based on acoustic wave communication technology includes a plurality of measurement nodes and a sub-measurement system. The measurement nodes are arranged on a solid sound transmission medium of a device under test. The measurement nodes are connected to each other through acoustic wave communication, and the sub-measurement nodes are connected to the measurement system through communication. The sub-measurement system is an upper-level sub-measurement system and / or a parallel sub-measurement system. The measurement node includes a CPU module, a power management module, a sensor measurement module, an acoustic wave communication module, and a sensor. The CPU module is connected to the power management module, the sensor measurement module, and the acoustic wave communication module respectively. One end of the sensor is connected to the sensor measurement module, and the other end is arranged on the solid sound transmission medium of the device under test.

[0008] Preferably: the CPU module implements the QPSK communication strategy of the measurement node through the acoustic signal transceiver control circuit.

[0009] Preferably, the CPU module is provided with a network communication interface, which includes optical fiber communication, RS485 serial bus, Ethernet, 4G / 5G, WIFI, and Bluetooth communication interface.

[0010] Preferably: the power management module is provided with a power supply interface, and the power supply interface includes an alternating current, a solar cell and an energy storage battery power supply interface.

[0011] Preferably, the sound wave frequency adopts the ultrasonic frequency band.

[0012] Preferably, the sound wave signal transmitter of the sound wave communication module is a Cypress ultrasonic solid-state speaker, which is closely attached to the solid surface to achieve the function of coupling the sound wave to the solid medium for propagation.

[0013] Preferably, the sound wave signal receiver of the sound wave communication module is a MEMS microphone chip, which is closely attached to the solid surface to realize the function of collecting the sound wave signal propagating in the solid medium.

[0014] A communication method of a wireless sensor system based on acoustic wave communication technology comprises the following steps:

[0015] Step 1: construct an acoustic emission power level of the acoustic wave communication module according to the emission power coefficient corresponding to the amplitude of the emission point waveform of the measurement node.

[0016] The acoustic emission power gear is 0-99 gears, gear 0 is the transmission power coefficient of the transmission power corresponding to the maximum amplitude of the transmission point waveform, gear 99 is the transmission power coefficient of the transmission power corresponding to the minimum amplitude of the transmission point waveform, and the transmission power coefficient between the transmission power corresponding to the minimum amplitude of the transmission point waveform and the transmission power corresponding to the maximum amplitude of the transmission point waveform is divided into 98 intervals, and each interval corresponds to a gear.

[0017] Step 2: Initialize the network nodes. During initialization, the nodes broadcast their heartbeat messages at the maximum power level and wait for heartbeat replies. When other nodes receive the heartbeat messages, they need to send messages at the same transmission power level to verify the heartbeats.

[0018] Step 3: After receiving the initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the current node communication signal. A0 , then downshift to broadcast its own heartbeat message and wait for the heartbeat reply. When other nodes receive the heartbeat message, they need to send a message reply to verify the heartbeat at the same transmission power.

[0019] Step 4: After receiving the non-initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the communication signal of the current node. A , and then obtain the power level / signal-to-noise ratio transfer coefficient, downshift to broadcast its own heartbeat message, and wait for the heartbeat reply. If the current node does not receive the heartbeat reply, the node sends the heartbeat message with the corresponding level of the heartbeat message sent last time plus 1, and waits for the heartbeat reply. If the current node receives the heartbeat reply, the initialization operation is completed.

[0020] Step 5: After initialization, the node broadcasts information based on the transmission coefficient and the transmission power corresponding to the gear position to complete the acoustic wave communication.

[0021] Preferably, the transmit power coefficient formula is calculated as follows:

[0022]

[0023] Among them, K represents the transmission power coefficient, A represents the amplitude corresponding to the actual transmission power, and A max Indicates the amplitude corresponding to the maximum power.

[0024] Preferably, the transfer coefficient calculation formula is as follows:

[0025]

[0026] Among them, K represents the transfer coefficient, A represents the amplitude corresponding to the actual transmitted power, A0 represents the initial amplitude of the sound wave at the sound source, and A max Indicates the amplitude corresponding to the maximum power.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention introduces the acoustic wave communication technology and effectively solves the information interaction problem between measurement nodes with a new communication idea, thus expanding the engineering application field of the wireless sensor network technology under special working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of a wireless sensing system based on acoustic wave communication technology;

[0030] Figure 2 A block diagram of the measurement node composition based on acoustic wave communication technology;

[0031] Figure 3 Provide a block diagram for the acoustic wave communication module;

[0032] Figure 4 It is a curve diagram showing the relationship between the carrier waveform of the acoustic wave transmission power and the power coefficient;

[0033] Figure 5 This is the flow chart of the acoustic wave transmission communication node initialization and power adjustment algorithm. DETAILED DESCRIPTION

[0034] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0035] With the rapid development of wireless communication technology, wireless sensor network technology (WSN) is becoming an emerging development direction for sensors and detection systems. Since electromagnetic wave wireless communication has many unique advantages in the process of engineering implementation, such as easy microelectronics of actuators, it has become the only choice for WSN communication networking solutions. However, electromagnetic wave wireless communication networking technology is not perfect. In reality, there are also disadvantages such as high cost, line-of-sight communication, and poor obstacle avoidance. For special fields such as dam safety monitoring (especially corridor environments), the above shortcomings will strictly limit the engineering promotion and application of wireless communication networking technology. To this end, we provide a wireless sensor system based on acoustic wave communication technology, such as Figure 1-3 As shown, it includes multiple measurement nodes and sub-measurement systems. The measurement nodes are arranged on the solid sound transmission medium of the device under test. The measurement nodes are connected by sound wave communication. The measurement nodes use sound waves as the transmission medium to realize communication and networking functions. The sub-measurement nodes are connected to the measurement system in communication. The sub-measurement system is an upper-level sub-measurement system and / or a parallel sub-measurement system, such as Figure 2 As shown, the measurement node includes a CPU module, a power management module, a sensor measurement module, an acoustic wave communication module, and a sensor. The CPU module is connected to the power management module, the sensor measurement module, and the acoustic wave communication module respectively. One end of the sensor is connected to the sensor measurement module, and the other end is arranged on the solid sound transmission medium of the device under test.

[0036] The CPU module should have relatively strong computing and analysis capabilities, and it is advisable to use ARM chips of Cortex-M3 or above. The CPU should also be pre-installed with an operating system, such as Windows, Linux, and support file systems and Ethernet communication protocols. The networking protocol of the wireless sensor adopts a ZigBee-like wireless ad hoc networking protocol and a low-power LAN protocol that complies with the IEEE802.15.4 standard. It meets the requirements of low cost, low energy, and high fault tolerance.

[0037] The acoustic wave communication module is the core module of the measurement node. In environments with severe line-of-sight obstruction, such as corridor environments, it replaces electromagnetic wave communication and uses acoustic waves as the transmission medium to achieve communication and networking functions between measurement nodes. Figure 3 This is a schematic diagram of the structure of the sound wave communication module. The sound wave communication module consists of three parts: a sound wave signal transceiver control circuit, a sound wave signal receiver, and a sound wave signal transmitter. The sound wave signal transceiver control circuit demodulates the input information of the sound wave signal receiver under the control of the CPU, and the sound wave signal transmitter modulates the information sent by the CPU and sends it out in the form of sound waves.

[0038] In order to realize the networking expansion function, the measurement node is also equipped with a network communication interface (wired such as optical fiber communication, RS485 serial bus, Ethernet; wireless such as 4G / 5G, WIFI, Bluetooth, etc.), which can realize the networking function between the upper measurement system (mainly the measurement and control computer of the control center) and the parallel measurement system (mainly the same type of measurement subsystems of other working sections). The network communication interface (optional) set in the measurement node is mainly used for the expansion application with other network devices, and can also provide traditional electromagnetic wave communication networking functions for application scenarios with line-of-sight communication conditions, providing flexible and diverse communication networking means for WSN.

[0039] The power supply of the measurement node should have a variety of power supply interface capabilities. The power management module is provided with a power supply interface, which includes AC, solar cell and energy storage battery power supply interfaces. It supports multiple power supply forms such as AC (AC220V, AC36V, etc.), solar cells (parts with sunlight conditions such as dam tops), and energy storage batteries (lead-acid batteries, lithium batteries, etc.). The power management module realizes the conversion of various forms of power into the power system required by the internal circuit of the measurement node, mainly +3.3VDC, and should also have low-power energy management functions such as high conversion efficiency and sleep / standby.

[0040] The acoustic signal transmitter of the acoustic communication module can use a Cypress ultrasonic solid-state speaker, which is close to the solid surface to achieve the function of coupling the acoustic wave to the solid medium for propagation.

[0041] The acoustic signal receiver of the acoustic communication module can use a MEMS microphone chip, which can be close to the solid surface to collect the acoustic wave signals propagating in the solid medium.

[0042] Since the dam safety monitoring system is used in an environment without relative motion, there will be no Doppler effect.

[0043] In order to avoid causing a bad user experience, the sound wave frequency adopts the ultrasonic frequency band (2000-20000Hz range, preferably 3000-5000Hz range).

[0044] The measurement sensor module of the measurement node is designed according to the specific form of the sensor being measured, and complies with the normative requirements related to the measurement function in the automatic collection device for dam safety monitoring data DLT1134-2018.

[0045] To eliminate the multipath effect, under the support of the CPU, the QPSK (Quadrature Phase Shift Keying) communication strategy is implemented through the acoustic signal transceiver control circuit. Therefore, the CPU module implements the QPSK communication strategy of the measurement node through the acoustic signal transceiver control circuit.

[0046] The acoustic wave communication module interacts with the CPU through the data bus and the management bus, wherein the data bus communicates data externally through the acoustic emission unit, and the management bus is responsible for configuring the acoustic wave communication module and collecting information.

[0047] The power of the acoustic wave communication module is designed to be 0-99 gears and is configured through the management bus. The acoustic wave communication module has a signal-to-noise ratio (SNR) measurement function and can report SNR data through the management bus.

[0048] This embodiment introduces acoustic wave communication technology to effectively solve the information interaction problem between measurement nodes with a new communication idea, expands the engineering application field of wireless sensor network technology under special working conditions, and provides a feasible technical implementation method for WSN under the condition of electromagnetic wave communication path constraints.

[0049] This acoustic wave communication system adopts a three-layer structure for data interaction and management:

[0050] Physical layer: responsible for the modulation and propagation of sound wave signals. This layer handles the generation, modulation and characteristics of the sound wave carrier and its transmission medium to ensure the effective transmission of signals in different environments.

[0051] Link layer: manages the data encapsulation, transmission verification and error control of acoustic signals. At this layer, data packets are encapsulated into a frame structure with a specific format. Each frame contains necessary control information and error checking codes to ensure data integrity and reliable transmission.

[0052] Application layer: handles high-level data processing and parsing tasks, including parsing of communication content and generation or consumption of application data. This layer implements specific application logic, provides user interfaces, and performs end-to-end data interaction.

[0053] Link layer protocol specification, data encapsulation structure is as follows:

[0054] Message header:

[0055] Device ID uniquely identifies the sending device and is used for device identification and data routing in the network.

[0056] The acoustic emission power level is dynamically adjusted according to the communication distance and environmental conditions to optimize power consumption and signal strength.

[0057] The target ID is used to identify the final target of the communication. When the intermediate node determines that the target ID does not match itself, it needs to forward the message immediately.

[0058] Source transmission timestamp records the precise time of data transmission for synchronization and delay measurement.

[0059] The most recent forwarding timestamp records the precise time when the data was most recently forwarded, which is used for synchronization and latency measurement.

[0060] Message data:

[0061] It carries the application layer data actually transmitted, and its length and format are determined according to the application layer requirements.

[0062] Message end:

[0063] Contains a checksum field for error detection, usually CRC (cyclic redundancy check) or other checksum methods, to ensure the integrity of the data during transmission.

[0064] Device communication and network management

[0065] Devices exchange data in the acoustic wave signals of the physical layer through the link layer protocol. By analyzing the device ID, acoustic emission power coefficient and emission timestamp, the device can identify the source, evaluate the distance of the signal source, and adjust the local transmission power accordingly. Each node level needs to perform data verification and error correction. In addition, when the device responds to the received data packet, it will send a confirmation message to complete the communication cycle.

[0066] Network topology configuration

[0067] In the network topology, chain topology or tree topology is selected as the topology of the acoustic communication network. The node that manages the device connected through other media is set as the root node. Each node needs to record its own parent / child node ID and only communicate directly with the adjacent parent / child nodes. Intermediate nodes are required as relays for cross-node communication.

[0068] Network node power configuration

[0069] Different from radio communication, in acoustic emission communication based on sound waves, the core component of the acoustic emission communication module is the acoustic emission transducer. In communication, the energy consumption of the transducer is relatively large, and the propagation of sound waves in solid media such as corridors and pipelines attenuates rapidly with increasing distance. Each node needs to select the appropriate acoustic emission power to reduce the power consumption of the communication node while meeting the stable communication requirements.

[0070] The power of the acoustic communication module is configured through the management bus. The power coefficient of the acoustic communication module is a logarithmic coefficient, which reflects the decibel ratio of the current transmission power to the maximum power. The gear setting is shown as follows: Figure 4As shown, the acoustic emission power gear is 0-99 gears, gear 0 is the emission power coefficient of the emission power corresponding to the maximum amplitude of the emission point waveform, gear 99 is the emission power coefficient of the emission power corresponding to the minimum amplitude of the emission point waveform, and the emission power coefficient between the emission power corresponding to the minimum amplitude of the emission point waveform and the emission power coefficient corresponding to the maximum amplitude of the emission point waveform is divided into 98 intervals, each interval corresponding to a gear. The power coefficient calculation formula is as follows (1).

[0071]

[0072] Among them, K represents the transmission power coefficient, A represents the amplitude corresponding to the actual transmission power, and A max Indicates the amplitude corresponding to the maximum power.

[0073] The acoustic wave communication module sets the lowest allowed communication signal-to-noise ratio to 20 dB. The signal-to-noise ratio measurement data is measured through the acoustic wave communication module and the signal-to-noise ratio data is uploaded to the CPU.

[0074] For acoustic wave communication in solid media, the communication quality depends on the attenuation of the acoustic wave in the medium. The acoustic wave communication medium of the present invention is often not an isotropic, standard-shaped structure. Therefore, it is difficult to establish an attenuation model of the acoustic wave in the target scene before the sensor system is deployed. However, during the transmission of the acoustic wave signal, the signal decays exponentially with respect to the propagation distance at a relatively stable rate, that is, a simplified attenuation formula (2) for the signal amplitude can be obtained.

[0075] A(x)=A0e -αx (2)

[0076] Among them, A(x) is the amplitude of the sound wave at a distance x, A0 is the initial amplitude of the sound wave at the sound source, α is the attenuation coefficient, which is considered to be an approximate constant here, and x is the distance the sound wave propagates.

[0077] The attenuation of the acoustic wave amplitude transmission affects the signal-to-noise ratio of communication, as shown in formula (3):

[0078]

[0079] in, The amplitude of the sound wave is A n The signal-to-noise ratio, A s is the amplitude of the sound wave, A n is the amplitude of the sound wave.

[0080] Combining formula (1), the linear transfer coefficient of power level with respect to signal-to-noise ratio can be established:

[0081]

[0082] Among them, K represents the transfer coefficient, A represents the amplitude corresponding to the actual transmitted power, A0 represents the initial amplitude of the sound wave at the sound source, and A max Indicates the amplitude corresponding to the maximum power.

[0083] In the node initialization process, the above formula can be used to calculate the power level that is most suitable for the current node communication link.

[0084] A communication method of a wireless sensor system based on acoustic wave communication technology comprises the following steps:

[0085] Step 1: construct an acoustic emission power level of the acoustic wave communication module according to the emission power coefficient corresponding to the amplitude of the emission point waveform of the measurement node.

[0086] Step 2: Initialize the network nodes. During initialization, the nodes broadcast their heartbeat messages at the maximum power level and wait for heartbeat replies. The heartbeat message format is shown in Table 1. When other nodes receive the heartbeat message, they need to send a message reply to verify the heartbeat at the same transmission power level.

[0087] Table 1 Heartbeat message format

[0088]

[0089] Step 3: After receiving the initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the current node communication signal. A0 , then reduce the power to -3 gears to broadcast its own heartbeat message and wait for the heartbeat reply. When other nodes receive the heartbeat message, they need to send a message reply to verify the heartbeat at the same transmission power.

[0090] Step 4: After receiving the non-initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the communication signal of the current node. A (SNR -3 ), and then obtain the power level / signal-to-noise ratio transfer coefficient, downshift to broadcast its own heartbeat message, and wait for the heartbeat reply. If the current node does not receive the heartbeat reply, the node sends the heartbeat message with the corresponding level of the heartbeat message sent last time plus 1, and waits for the heartbeat reply. If the current node receives the heartbeat reply, the initialization operation is completed.

[0091] Step 5: After initialization, the node broadcasts information based on the transmission coefficient and the transmission power corresponding to the gear position to complete the acoustic wave communication.

[0092] During the operation of the network node, heartbeat communication needs to be sent to the parent / child node at a cycle that is less than 1 / 2 of the data communication cycle. When the heartbeat cannot be verified, the network node initialization process needs to be re-executed to ensure the smoothness of the link.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A wireless sensing system based on acoustic wave communication technology, characterized in that: The method comprises a plurality of measurement nodes and sub-measurement systems, wherein the measurement nodes are arranged on the solid sound transmission medium of the device under test, the measurement nodes are connected to each other through acoustic wave communication, and the sub-measurement nodes are communicatively connected with the measurement system; the sub-measurement system is an upper-level sub-measurement system and / or a parallel sub-measurement system, and the measurement nodes comprise a CPU module, a power management module, a sensor measurement module, an acoustic wave communication module, and a sensor, wherein the CPU module is respectively connected to the power management module, the sensor measurement module, and the acoustic wave communication module, one end of the sensor is connected to the sensor measurement module, and the other end is arranged on the solid sound transmission medium of the device under test.

2. The wireless sensing system based on acoustic wave communication technology according to claim 1, characterized in that: The CPU module implements the QPSK communication strategy of the measurement node through the acoustic signal transceiver control circuit.

3. The wireless sensing system based on acoustic wave communication technology according to claim 2, characterized in that: The CPU module is provided with a network communication interface; the network communication interface includes optical fiber communication, RS485 serial bus, Ethernet, 4G / 5G, WIFI, and Bluetooth communication interface.

4. The wireless sensing system based on acoustic wave communication technology according to claim 3 is characterized in that: The power management module is provided with a power supply interface, and the power supply interface includes an alternating current, a solar cell and an energy storage battery power supply interface.

5. The wireless sensing system based on acoustic wave communication technology according to claim 4, characterized in that: The sound wave frequency adopts the ultrasonic frequency band.

6. The wireless sensing system based on acoustic wave communication technology according to claim 5, characterized in that: The acoustic signal transmitter of the acoustic communication module is a Cypress ultrasonic solid-state speaker, which is in close contact with the solid surface to achieve the function of coupling the acoustic wave to the propagation in the solid medium; the acoustic signal receiver of the acoustic communication module is a MEMS microphone chip, which is in close contact with the solid surface to achieve the function of collecting the acoustic wave signal propagating in the solid medium.

7. A communication method of a wireless sensor system based on acoustic wave communication technology according to claim 1, characterized in that: The following steps are involved: Step 1, constructing the acoustic emission power level of the acoustic wave communication module according to the emission power coefficient corresponding to the amplitude of the emission point waveform of the measurement node; Step 2: Initialize the network nodes. During initialization, the nodes broadcast their heartbeat messages at the maximum power level and wait for heartbeat replies. When other nodes receive the heartbeat messages, they need to send messages at the same transmission power level to verify the heartbeats. Step 3: After receiving the initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the current node communication signal. A0 , then downshift to broadcast its own heartbeat message and wait for the heartbeat reply; when other nodes receive the heartbeat message, they need to send a message reply to verify the heartbeat at the same transmission power; Step 4: After receiving the non-initial heartbeat, the node calculates the signal-to-noise ratio (SNR) of the communication signal of the current node. A , and then obtain the power level / signal-to-noise ratio transfer coefficient, downgrade to broadcast its own heartbeat message, and wait for the heartbeat reply; if the current node does not receive the heartbeat reply, the node sends the heartbeat message with the corresponding level of the heartbeat message sent last time plus 1, and waits for the heartbeat reply; if the current node receives the heartbeat reply, the initialization operation is completed; Step 5: After initialization, the node broadcasts information based on the transmission coefficient and the transmission power corresponding to the gear position to complete the acoustic wave communication.

8. The communication method according to claim 7, characterized in that: The acoustic emission power gear is 0-99 gears, gear 0 is the transmission power coefficient of the transmission power corresponding to the maximum amplitude of the transmission point waveform, gear 99 is the transmission power coefficient of the transmission power corresponding to the minimum amplitude of the transmission point waveform, and the transmission power coefficient between the transmission power corresponding to the minimum amplitude of the transmission point waveform and the transmission power corresponding to the maximum amplitude of the transmission point waveform is divided into 98 intervals, and each interval corresponds to a gear.

9. The communication method according to claim 8, characterized in that: The formula for calculating the transmit power coefficient is as follows: Among them, K represents the transmission power coefficient, A represents the amplitude corresponding to the actual transmission power, and A max Indicates the amplitude corresponding to the maximum power.

10. The communication method according to claim 9, characterized in that: The formula for calculating the transfer coefficient is as follows: Among them, K represents the transfer coefficient, A represents the amplitude corresponding to the actual transmitted power, A0 represents the initial amplitude of the sound wave at the sound source, and A max Indicates the amplitude corresponding to the maximum power.

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