CN106656355B - Remote underwater acoustic communication system and control method thereof - Google Patents

Remote underwater acoustic communication system and control method thereof Download PDF

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CN106656355B
CN106656355B CN201610875843.5A CN201610875843A CN106656355B CN 106656355 B CN106656355 B CN 106656355B CN 201610875843 A CN201610875843 A CN 201610875843A CN 106656355 B CN106656355 B CN 106656355B
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communication module
communication
sea
sea communication
shallow
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CN106656355A (en
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闫志伟
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Kyland Technology Co Ltd
Beijing Armyfly Technology Co Ltd
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Kyland Technology Co Ltd
Beijing Armyfly Technology Co Ltd
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B13/00Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
    • H04B13/02Transmission systems in which the medium consists of the earth or a large mass of water thereon, e.g. earth telegraphy
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/29Repeaters
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B11/00Transmission systems employing sonic, ultrasonic or infrasonic waves
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/14Relay systems
    • H04B7/15Active relay systems

Abstract

The invention discloses a remote underwater acoustic communication system and a control method thereof, wherein the system comprises: the system comprises a plurality of shallow sea communication modules distributed in a shallow sea area and a plurality of deep sea communication modules distributed in an ocean vocal tract area; each shallow sea communication module corresponds to at least one deep sea communication module within a preset range from the shallow sea communication module; the shallow sea communication module is used for sending the communication signal to any corresponding deep sea communication module; receiving a communication signal forwarded by a corresponding deep sea communication module; the deep sea communication module is used for transmitting the communication signal to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode when receiving the communication signal transmitted by the corresponding shallow sea communication module; and when receiving the communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module. The remote underwater acoustic communication system provided by the embodiment of the invention realizes the remote communication of communication signals in seawater.

Description

Remote underwater acoustic communication system and control method thereof
Technical Field
The invention relates to the technical field of underwater acoustic communication, in particular to a remote underwater acoustic communication system and a control method thereof.
Background
With the further research and utilization of marine resources, underwater acoustic communication is more and more emphasized by people, however, when communication signals are transmitted in seawater, the propagation attenuation of sound intensity in seawater is serious, and the reason can be summarized into three aspects: (1) expansion loss: the attenuation of sound intensity caused by the continuous expansion of the wave front of sound wave in the process of transmission is also called geometric attenuation; (2) absorption loss: generally refers to the attenuation of acoustic intensity due to medium viscosity, thermal conduction, and other relaxation processes; (3) scattering: caused by suspended particles such as silt, bubbles, plankton and the like and the nonuniformity of the medium.
In the prior art, the transmission distance of the remote underwater acoustic communication is between 20km and 200km, and the communication signals are seriously attenuated after being propagated in a long distance, so that the error rate is increased to cause abnormal communication.
Therefore, how to overcome the problem of serious signal attenuation when communication signals are transmitted in seawater is an urgent need to solve the problem of realizing the longer-distance transmission of underwater acoustic communication.
Disclosure of Invention
The embodiment of the invention provides a remote underwater acoustic communication system and a control method thereof, which are used for solving the problem that the longer-distance transmission of underwater acoustic communication cannot be realized due to serious signal attenuation when communication signals are transmitted in seawater in the prior art.
The embodiment of the invention provides a remote underwater acoustic communication system, which comprises: the system comprises a plurality of shallow sea communication modules distributed in a shallow sea area and a plurality of deep sea communication modules distributed in an ocean vocal tract area; wherein the content of the first and second substances,
within a preset range from the shallow sea communication module, each shallow sea communication module corresponds to at least one deep sea communication module;
the shallow sea communication module is used for sending a communication signal to any corresponding deep sea communication module when the shallow sea communication module is used as a communication signal transmitting end to communicate with the target shallow sea communication module; when the communication signal receiving end is used for communicating with the target shallow sea communication module, the communication signal forwarded by the corresponding deep sea communication module is received;
the deep sea communication module is used for forwarding the communication signal to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode when the communication signal sent by the corresponding shallow sea communication module is received; and when receiving communication signals forwarded by other deep sea communication modules, sending the communication signals to the corresponding target shallow sea communication module.
In a possible implementation manner, in the remote underwater acoustic communication system provided in the embodiment of the present invention, each shallow sea communication module corresponds to only one deep sea communication module.
In a possible implementation manner, in the remote underwater acoustic communication system provided in the embodiment of the present invention, each of the shallow sea communication modules corresponds to the deep sea communication module closest to the shallow sea communication module.
In a possible implementation manner, in the remote underwater acoustic communication system provided in the embodiment of the present invention, the deep-sea communication module is further configured to determine a position of the corresponding shallow-sea communication module, and move synchronously with the corresponding shallow-sea communication module.
In a possible implementation manner, in the remote underwater acoustic communication system provided in the embodiment of the present invention, the shallow sea communication module and the corresponding deep sea communication module transmit communication signals in a high-frequency wireless, cable, or optical fiber manner.
In a possible implementation manner, in the remote underwater acoustic communication system provided in the embodiment of the present invention, communication signals are sent between the deep-sea communication modules in an orthogonal frequency division multiplexing transmission mode.
The embodiment of the invention also provides a control method of the remote underwater acoustic communication system, which comprises the following steps:
when the shallow sea communication module is used as a communication signal transmitting end to communicate with the target shallow sea communication module, the shallow sea communication module transmits a communication signal to any corresponding deep sea communication module;
when the deep sea communication module receives the communication signal sent by the corresponding shallow sea communication module, the communication signal is forwarded to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode;
when the deep sea communication module receives communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module;
and when the shallow sea communication module is used as a communication signal receiving end to communicate with the target shallow sea communication module, the shallow sea communication module receives the communication signal forwarded by the corresponding deep sea communication module.
In a possible implementation manner, in the control method of the remote underwater acoustic communication system provided in the embodiment of the present invention, the method further includes:
the deep sea communication module determines the position of the corresponding shallow sea communication module and synchronously moves along with the corresponding shallow sea communication module so as to keep the position within a preset range from the corresponding shallow sea communication module.
In a possible implementation manner, in the control method of the remote underwater acoustic communication system provided in the embodiment of the present invention, the shallow sea communication module and the corresponding deep sea communication module transmit communication signals in a high-frequency wireless, cable, or optical fiber manner.
In a possible implementation manner, in the control method of the remote underwater acoustic communication system provided in the embodiment of the present invention, communication signals are sent between the deep-sea communication modules in an orthogonal frequency division multiplexing transmission mode.
The invention has the following beneficial effects:
the embodiment of the invention provides a remote underwater acoustic communication system and a control method thereof, wherein the remote underwater acoustic communication system comprises: the system comprises a plurality of shallow sea communication modules distributed in a shallow sea area and a plurality of deep sea communication modules distributed in an ocean vocal tract area; each shallow sea communication module corresponds to at least one deep sea communication module within a preset range from the shallow sea communication module; the shallow sea communication module is used for sending a communication signal to any corresponding deep sea communication module when the shallow sea communication module is used as a communication signal transmitting end to communicate with the target shallow sea communication module; when the communication signal receiving end is used for communicating with the target shallow sea communication module, the communication signal forwarded by the corresponding deep sea communication module is received; the deep sea communication module is used for transmitting the communication signal to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode when receiving the communication signal transmitted by the corresponding shallow sea communication module; and when receiving the communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module. The remote underwater acoustic communication system provided by the embodiment of the invention utilizes the principle that the loss of communication signals is extremely low when low-frequency acoustic signals are transmitted in the ocean sound track area, at least one deep sea communication module corresponding to each shallow sea communication module is arranged in the ocean sound track area within a preset range away from the shallow sea communication module, the shallow sea communication module is used for sending the communication signals to any corresponding deep sea communication module, the deep sea communication module is used for forwarding the communication signals to any deep sea communication module corresponding to a target shallow sea communication module in a low-frequency wireless mode, and then the deep sea communication module is used for forwarding the communication signals to the target shallow sea communication module. Because the loss of the low-frequency communication signals transmitted in the ocean sound channel area is extremely low, the distance between the deep sea communication modules can be thousands of kilometers, and further distance transmission of the communication signals in the sea water is realized.
Drawings
Fig. 1 is a schematic structural diagram of a remote underwater acoustic communication system according to an embodiment of the present invention;
fig. 2 is a schematic signal interaction diagram of a remote underwater acoustic communication system according to an embodiment of the present invention;
fig. 3 is a flowchart of a control method of the remote underwater acoustic communication system according to an embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a remote underwater acoustic communication system and a control method thereof, aiming at the problem that the communication signal is seriously attenuated when being transmitted in seawater and further distance transmission of underwater acoustic communication cannot be realized in the prior art.
The following describes in detail a specific implementation of the remote underwater acoustic communication system and the control method thereof according to an embodiment of the present invention with reference to the accompanying drawings. The sizes and shapes of the various blocks in the drawings are not to scale and are merely intended to illustrate the invention.
An embodiment of the present invention provides a remote underwater acoustic communication system, as shown in fig. 1, including: a plurality of shallow sea communication modules 101 distributed in a shallow sea area, and a plurality of deep sea communication modules 102 distributed in an ocean vocal tract area; wherein the content of the first and second substances,
each shallow sea communication module 101 corresponds to at least one deep sea communication module 102 within a preset range from the shallow sea communication modules 101;
the shallow sea communication module 101 is used for sending a communication signal to any corresponding deep sea communication module 102 when the shallow sea communication module 101 is used as a communication signal transmitting end to communicate with the target shallow sea communication module 101; when the communication signal receiving end is used for communicating with the target shallow sea communication module 101, the communication signal forwarded by the corresponding deep sea communication module 102 is received;
the deep sea communication module 102 is configured to forward a communication signal to any one deep sea communication module 102 corresponding to the target shallow sea communication module 101 in a low-frequency wireless manner when receiving the communication signal sent by the corresponding shallow sea communication module 101; and when receiving the communication signals forwarded by the other deep sea communication modules 102, forwarding the communication signals to the corresponding target shallow sea communication module 101.
According to the remote underwater acoustic communication system provided by the embodiment of the invention, by utilizing the principle that the loss of communication signals is extremely low when low-frequency acoustic signals are transmitted in the ocean sound channel area, at least one deep sea communication module 102 corresponding to each shallow sea communication module 101 is arranged in the ocean sound channel area within a preset range away from the shallow sea communication module 101, the shallow sea communication module 101 sends the communication signals to any corresponding deep sea communication module 102, the deep sea communication module 102 forwards the communication signals to any corresponding deep sea communication module 102 of a target shallow sea communication module 101 in a low-frequency wireless mode, and then the deep sea communication module 102 forwards the communication signals to the target shallow sea communication module 101. Because the loss of the low-frequency communication signals transmitted in the ocean sound track area is extremely small, the distance between the deep-sea communication modules 102 can be thousands of kilometers, and therefore the communication signals can be transmitted in the sea at a longer distance.
It should be noted that reference to "shallow sea" or "deep sea" in the embodiments of the present invention is the same concept as "shallow sea" or "deep sea" as understood by those skilled in the art, for example "shallow sea" may be, but is not limited to, understood as an area having a water depth of less than 500 meters and "deep sea" may be, but is not limited to, understood as an area having a water depth of greater than 500 meters.
The following explains the principle of extremely low loss when low frequency acoustic signals are transmitted in the ocean channel region:
when the communication signal is transmitted in the seawater in the form of an acoustic signal, the sound velocity of the acoustic signal is related to factors such as temperature, pressure, salinity and the like in the seawater, and the lower the temperature is, the slower the sound velocity is; the higher the pressure, the faster the speed of sound. The temperature change in the seawater is caused by solar irradiation, so the temperature decreases with increasing depth of the seawater, while the pressure increases with increasing depth of the seawater. Therefore, as the depth of the seawater increases, the sound velocity of the acoustic signal becomes slower due to the decrease of the temperature of the seawater, when the temperature of the seawater reaches the lowest value, the temperature basically does not change any more, and as the depth of the seawater continues to increase, the sound velocity becomes faster along with the pressure of the seawater. Therefore, the sound velocity of the sound signal propagating in the sea water forms an upper layer and a lower layer in the whole ocean, the sound velocity of the sound signal at the upper layer is reduced along with the increase of the depth, the sound velocity of the sound signal at the lower layer is increased along with the increase of the depth, a special acoustic waveguide channel, namely a sound channel shaft, is formed at the boundary of the two layers, and the sound signal is always bent towards the direction with lower sound velocity during propagation, so that the sound signal is folded back to the sound channel shaft when propagating above and below the sound channel shaft, the energy of the sound signal is concentrated in a water layer with certain thickness above and below the sound channel shaft, and the energy loss is. When the acoustic signal is transmitted at a small angle deviating from the sound channel axis, the acoustic signal is coupled with the acoustic waveguide channel by means of refraction, and when the low-frequency signal which is not easily absorbed by seawater is transmitted in the acoustic waveguide channel, the long-distance transmission can be realized by extremely low loss.
The sound channel axis is generally located at a water depth of 900-1300 m, and is averagely located at a position with a water depth of about 1200 m, but the position of the sound channel axis varies with the geographical position, for example, the sound channel axis in some tropical sea areas can be up to 2000 m, while the position of the sound channel axis in temperate sea areas rises with the increase of latitude, and can rise to a depth of 200-500 m, and in sea areas of two polar regions of the earth, the sound channel axis is located near the sea surface. Therefore, in practical implementation, the deep-sea communication module may be disposed at a position near the sound channel axis according to an actual geographic position, and the closer the position of the deep-sea communication module is to the sound channel axis, the smaller the loss of the acoustic signal is, and thus the longer the distance the communication signal travels.
In particular implementations, the shallow sea communication module 101 is typically located in a shallow sea area with a water depth of about 300 meters. Each shallow sea communication module 101 can set up in the shallow sea submarine ship, and the submarine ship sets up the position of the depth of water about 300 meters under water, when guaranteeing that submarine ship is submerged this position easily, can make shallow sea communication module 101 when transmitting communication signal, be difficult for receiving the influence of sea water surface other factors.
In the remote underwater acoustic communication system provided by the embodiment of the present invention, based on the principle that the loss of the low-frequency acoustic signal is extremely low when the low-frequency acoustic signal is transmitted in the ocean acoustic channel region, at least one deep sea communication module 102 corresponding to each shallow sea communication module 101 is arranged in the ocean acoustic channel region within a preset range from the shallow sea communication module 101, where the preset range may be the maximum distance at which the shallow sea communication module 101 can transmit the communication signal to the deep sea communication module 102, and the size of the preset range may be determined according to the actual communication signal transmission mode. As shown in fig. 1, two shallow sea communication modules 101 correspond to a plurality of deep sea communication modules 102 in fig. 1, for example, and the number of the shallow sea communication modules 101 and the deep sea communication modules 102 is not limited. In a specific implementation, a plurality of deep-sea communication modules 102 may be provided to form a deep-sea communication network in the deep sea, and one shallow-sea communication module 101 may be provided corresponding to the plurality of deep-sea communication modules 102 to implement transmission of communication signals of different functions, or may be used as a spare deep-sea communication module 102. Because the low-frequency communication signals have extremely low loss in the ocean sound track area, the distance between the deep sea communication modules 102 can be set to be thousands of kilometers, so that the long-distance transmission of the communication signals in the sea water is realized, and the transmission distance can reach thousands of kilometers and far exceeds the transmission distance of 20km to 200km in the prior art.
In practical applications, each shallow sea communication module 101 may be disposed in an underwater boat in a shallow sea area, and each deep sea communication module 102 is preferably located directly below the corresponding shallow sea communication module 101, so that the distance between each deep sea communication module 102 and the corresponding shallow sea communication module 101 is the closest, and the loss of communication signals transmitted between the deep sea communication module 102 and the corresponding shallow sea communication module 101 is reduced.
Referring to fig. 2, taking two shallow sea communication modules corresponding to two deep sea communication modules respectively as an example, a signal interaction process in the remote underwater acoustic communication system provided by the embodiment of the present invention is described, where the shallow sea communication module a corresponds to the deep sea communication module a ', and the shallow sea communication module B corresponds to the deep sea communication module B', and the method includes the following steps:
s201, the shallow sea communication module A sends a communication signal to the deep sea communication module A';
s202, the deep sea communication module A 'forwards a communication signal to a deep sea communication module B' in a low-frequency wireless mode;
s203, the deep sea communication module B' forwards the communication signal to the shallow sea communication module B;
and S204, the shallow sea communication module B receives the communication signal.
Specifically, in the remote underwater acoustic communication system provided by the embodiment of the present invention, each shallow sea communication module 101 corresponds to only one deep sea communication module 102. In this way, within a preset range from the shallow sea communication module 101, the deep sea communication module 102 is arranged, so that the system is simpler and the transmission process of the communication signal is easier to control. The deep sea communication module 102 is preferably disposed at a vertical position of the shallow sea communication module 101 so that a loss generated when a communication signal is transmitted between the shallow sea communication module 101 and the deep sea communication module 102 is small.
More specifically, in the remote underwater acoustic communication system provided by the embodiment of the present invention, each shallow sea communication module 101 corresponds to the deep sea communication module 102 closest to the shallow sea communication module. When a plurality of deep-sea communication modules 102 exist within a preset range from the shallow-sea communication module 101, the shallow-sea communication module 101 corresponds to the deep-sea communication module 102 closest to the shallow-sea communication module, so that loss generated during transmission of a communication signal is small.
Further, in the underwater acoustic communication system provided by the embodiment of the present invention, the deep-sea communication module 102 is further configured to determine a position of the corresponding shallow-sea communication module 101, and move synchronously with the corresponding shallow-sea communication module 101. In this way, the deep sea communication module 102 can be maintained within a preset range from the corresponding shallow sea communication module 101. Specifically, the deep sea communication module 102 may be controlled to follow the corresponding shallow sea communication module 101 in the following manner:
the first method is as follows: the deep sea communication module 102 acquires the position information of the corresponding shallow sea communication module 101 at set time intervals, and synchronously moves along with the corresponding shallow sea communication module 101 according to the position information; in practical applications, the position of the corresponding shallow sea communication module 101 can be acquired by the deep sea communication module 102 at intervals (e.g. 10s, 20s or 30s, etc.) to follow the corresponding shallow sea communication module 101 to move synchronously;
the second method comprises the following steps: the deep sea communication module 102 acquires the position information of the corresponding shallow sea communication module 101 through the communication buoy and synchronously moves along with the corresponding shallow sea communication module 101 according to the acquired position information; in practical application, the method can be realized by arranging a communication buoy corresponding to the shallow sea communication module;
the third method comprises the following steps: the deep sea communication module 102 is connected with the corresponding shallow sea communication module through a connecting part to move synchronously with the corresponding shallow sea communication module 101; a deep sea communications module is connected to a corresponding shallow sea communications module, for example, using a chain.
The deep sea communication module 102 moves synchronously with the corresponding shallow sea communication module 101, so that communication signals can be transmitted smoothly between the shallow sea communication module 101 and the deep sea communication module 102. The above three following ways are preferred embodiments of the present invention, and in practical applications, other ways may also be adopted, and are not limited herein.
Specifically, in the underwater acoustic communication system provided by the embodiment of the present invention, the shallow sea communication module 101 and the corresponding deep sea communication module 102 transmit communication signals therebetween in a high-frequency wireless, cable, or optical fiber manner.
In practical applications, when performing the remote underwater acoustic communication, since the distance between the shallow sea communication module 101 and the corresponding deep sea communication module 102 is much smaller than the distance between the shallow sea communication modules 101, for example, the distance between the shallow sea communication module 101 and the corresponding deep sea communication module 102 is generally about one kilometer, and the transmission loss of the communication signal passing through the distance is not very large, the communication signal can be transmitted between the shallow sea communication module 101 and the corresponding deep sea communication module 102 in various manners, for example, in a manner of high frequency wireless, cable, or optical fiber.
Specifically, in the remote underwater acoustic communication system provided in the embodiment of the present invention, each deep-sea communication module 102 may include a hydrophone array, and preferably includes a fiber grating-type hydrophone array.
The fiber grating hydrophone array is integrated in each deep-sea communication module 102, so that the optimal communication signal receiving capability can be realized. The fiber bragg grating type hydrophone is based on the principle that the reflection wavelength of the fiber bragg grating moves along with the change of external stress, a plurality of fiber bragg gratings are engraved on one optical fiber, and distributed sensing is easy to form. The sensitivity of 0.61MHz/Pa can be achieved when the underwater sound signal is 100 Hz. Has higher sensitivity than the interference type optical fiber hydrophone. The fiber grating type hydrophone array is integrated in the deep sea communication module 102, time division multiplexing technology is adopted to control each fiber grating type hydrophone, and in the assembly process of the fiber grating type hydrophone array, the problem of ensuring the optical balance of the system when a large number of thousands of devices exist is solved.
In a specific implementation, in the remote underwater acoustic communication system provided in the embodiment of the present invention, the deep sea communication modules 102 transmit communication signals in an Orthogonal Frequency Division Multiplexing (OFDM) transmission mode.
The deep-sea communication modules 102 transmit communication signals in an orthogonal frequency division multiplexing transmission mode, so that the bearing capacity of a communication channel can be improved. The communication rate is improved by removing Cyclic Prefix (CP), and the frequency domain adaptive equalization algorithm is adopted to overcome the multipath effect, so that the frequency utilization rate and the signal communication rate of the uncorrelated frequency shift keying underwater acoustic communication are improved. The multi-carrier communication system divides the whole bandwidth resource into a plurality of independent narrow-band sub-channels, and carries out parallel information transmission on the sub-channels, and the key of the multi-carrier communication lies in the efficient division of the channel resource and the reasonable selection of the communication mode, and reduces the interference between the sub-channels. Unlike the general OFDM technology, the OFDM in the embodiment of the present invention divides the communication information of one user into multiple virtual users, and performs communication by using an OFDM mechanism to provide channel carrying capability. Multiple Modulation modes such as Amplitude-shift keying (ASK), Frequency Shift Keying (FSK), phase-shift keying (PSK), Multilevel Quadrature Amplitude Modulation (MQAM) and the like can be flexibly adopted for each subchannel, wherein FSK reliability is high, MQAM transmission rate is high, and a Modulation mode is adaptively selected according to a channel state. Compared with single carrier communication, OFDM enables bit rate on each sub-frequency band to be remarkably reduced, improves duration time of each code element, has strong multipath resistance, and is suitable for being applied to underwater acoustic channel environments with severe multipath.
In different depth sea areas, the structure of the multipath channel is different with the difference of the transmitting and receiving distance, and under the non-line of sight (NLOS) propagation environment, the amplitude of the received signal obeys the rayleigh distribution and the phase obeys the uniform distribution. Compensation for signal fading under different communication environment conditions needs to be established. The OFDM signal adopts a cyclic prefix-suffix mode as a protection time interval, and a decision feedback adaptive equalization algorithm is introduced to track the channel performance and overcome the requirement of a longer cyclic prefix aiming at the condition that the traditional frequency domain adaptive equalization algorithm needs the longer cyclic prefix.
Further, in the remote underwater acoustic communication method provided by the embodiment of the present invention, the plurality of deep sea communication modules 102 form an ad hoc network, and each deep sea communication module 102 is further configured to serve as a relay node for forwarding a communication signal.
The plurality of deep sea communication modules 102 form an ad hoc network, so that communication signals can be mutually transmitted among the deep sea communication modules 102, and the transmission distance of the communication signals can be longer. The plurality of deep sea communication modules 102 form an ad hoc network, and wireless communication between the deep sea communication modules 102 is realized even when there is no infrastructure (e.g., a base station).
Each deep-sea communication module 102 is also configured to act as a relay node for relaying the communication signal, so that the transmission distance of the communication signal can be further increased. In practical applications, if the distance between the shallow sea communication module 101 as the transmitting end and the target shallow sea communication module 101 is relatively long, after the shallow sea communication module 101 as the transmitting end transmits the communication signal to the corresponding deep sea communication module 102, the deep sea communication module 102 may forward the communication signal to another deep sea communication module 102, and then forward the communication signal to the deep sea communication module 102 corresponding to the target shallow sea communication module 101 through another deep sea communication module 102.
A deep sea communication module corresponding to the shallow sea communication module 101 as a transmitting end is taken as a, and a deep sea communication module corresponding to the target shallow sea communication module 101 is taken as a B for illustration. The deep sea communication module A and the deep sea communication module B are far away from each other, and the deep sea communication module A can forward communication signals to the deep sea communication module B by taking the deep sea communication module C as a relay node; alternatively, the deep sea communication module may be forwarded to the deep sea communication module D through the deep sea communication module C and then forwarded to the deep sea communication module B. The function of the deep sea communication module as a relay node for forwarding the communication signal is only illustrated here, and the number of times of forwarding the communication signal is not limited, and in practical applications, the number of times of forwarding may be determined according to factors such as an actual distance between the shallow sea communication module 101 as a transmitting end and the target shallow sea communication module 101, a communication signal attenuation condition, and an actual position of each deep sea communication module 102 in the deep sea.
In practical implementation, in the remote underwater acoustic communication system provided by the embodiment of the present invention, the frequency of the communication signal transmitted between the deep sea communication modules 102 is less than 1 kHz.
As shown in table 1, for example, when the frequencies of the communication signals transmitted between the deep-sea communication modules 102 are different, the PH of the seawater is 8.15, the salt solubility S of the seawater is 35%, and the temperature T is 15 ℃.
Table 1: absorbing attenuation situation during communication signal transmission in seawater
Frequency f (kHz) 0.5 1.0 3.5 7.0
Absorption coefficient α (dB/km) 0.025 0.074 0.277 0.63
10km absorption attenuation (dB) 0.25 0.74 2.77 6.3
100km absorption attenuation (dB) 2.5 7.4 27.7 63
1000km absorption attenuation (dB) 25 74 277 630
As can be seen from the table, when the frequency of the communication signal is a low-frequency acoustic signal of 1kHz or less, the absorption coefficient and the absorption attenuation at each depth are small, and for deep-sea ultra-long range communication of more than 1000km, a low-frequency acoustic signal of 0.5kHz or less is preferably used. The advantages of selecting the low-frequency wireless mode to transmit the communication signal are as follows: the time correlation radius of the low-frequency signal propagation fluctuation is long, and the impulse response time of the transmitting signal is far shorter than the time correlation radius of the phase fluctuation, so that the propagation phase fluctuation can be ignored in the duration time of the transmitting signal, the influence of frequency dispersion effect and multipath effect is small, the Doppler frequency shift is small, the channel stability is high, and the time gain is easy to obtain.
Based on the same inventive concept, embodiments of the present invention provide a control method for the above-mentioned remote underwater acoustic communication system, and because the principle of the control method for solving the problem is similar to that of the above-mentioned remote underwater acoustic communication system, the implementation of the control method can refer to the implementation of the above-mentioned remote underwater acoustic communication system, and repeated details are omitted. As shown in fig. 3, the control method includes:
s301, when the shallow sea communication module is used as a communication signal transmitting end to communicate with a target shallow sea communication module, the shallow sea communication module transmits a communication signal to any corresponding deep sea communication module;
s302, when the deep sea communication module receives the communication signal sent by the corresponding shallow sea communication module, the communication signal is forwarded to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode;
s303, when the deep sea communication module receives the communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module;
s304, when the shallow sea communication module is used as a communication signal receiving end to communicate with the target shallow sea communication module, the shallow sea communication module receives the communication signal forwarded by the corresponding deep sea communication module.
Specifically, the control method provided in the embodiment of the present invention further includes (not shown in the figure):
the shallow sea communication module controls the corresponding deep sea communication module to move synchronously, so that the deep sea communication module is located in a preset range from the shallow sea communication module.
Further, in the control method provided in the embodiment of the present invention, the deep-sea communication modules send the communication signals in an orthogonal frequency division multiplexing transmission mode.
Furthermore, in the control method provided by the embodiment of the present invention, the frequency of the communication signal transmitted between the deep-sea communication modules is less than 1 kHz.
Specifically, in the above control method provided by the embodiment of the present invention, the shallow sea communication module and the corresponding deep sea communication module transmit communication signals in a high-frequency wireless, cable or optical fiber manner.
According to the remote underwater acoustic communication system and the control method thereof, by utilizing the principle that the loss of communication signals is extremely low when low-frequency acoustic signals are transmitted in ocean sound channels, at least one deep sea communication module corresponding to each shallow sea communication module is arranged in an ocean sound channel area within a preset range away from the shallow sea communication module, the shallow sea communication module sends the communication signals to any corresponding deep sea communication module, the deep sea communication module forwards the communication signals to any deep sea communication module corresponding to a target shallow sea communication module in a low-frequency wireless mode, and then the deep sea communication module forwards the communication signals to the target shallow sea communication module. Because the loss of the low-frequency communication signals transmitted in the ocean sound channel area is extremely low, the distance between the deep sea communication modules can be thousands of kilometers, and further distance transmission of the communication signals in the sea water is realized.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. A remote underwater acoustic communication system, comprising: the system comprises a plurality of shallow sea communication modules distributed in a shallow sea area and a plurality of deep sea communication modules distributed in an ocean vocal tract area; wherein the content of the first and second substances,
within a preset range from the shallow sea communication module, each shallow sea communication module corresponds to at least one deep sea communication module;
the shallow sea communication module is used for sending a communication signal to any corresponding deep sea communication module when the shallow sea communication module is used as a communication signal transmitting end to communicate with the target shallow sea communication module; when the communication signal receiving end is used for communicating with the target shallow sea communication module, the communication signal forwarded by the corresponding deep sea communication module is received;
the deep sea communication module is used for forwarding the communication signal to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode when the communication signal sent by the corresponding shallow sea communication module is received; and when receiving the communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module.
2. The system of claim 1, wherein each of said shallow sea communication modules corresponds to only one of said deep sea communication modules.
3. The system of claim 1, wherein each of the shallow sea communication modules corresponds to the closest deep sea communication module.
4. The system of claim 2, wherein the deep-sea communication module is further configured to determine a location of the corresponding shallow-sea communication module and move synchronously with the corresponding shallow-sea communication module.
5. The system of claim 1, wherein the shallow sea communication module and the corresponding deep sea communication module transmit communication signals therebetween by means of high frequency wireless, cable or optical fiber.
6. The system of claim 1, wherein the deep-sea communication modules transmit communication signals therebetween using an orthogonal frequency division multiplexing transmission mode.
7. The method of controlling a remote underwater acoustic communication system according to any one of claims 1 to 6, comprising:
when the shallow sea communication module is used as a communication signal transmitting end to communicate with the target shallow sea communication module, the shallow sea communication module transmits a communication signal to any corresponding deep sea communication module;
when the deep sea communication module receives the communication signal sent by the corresponding shallow sea communication module, the communication signal is forwarded to any one deep sea communication module corresponding to the target shallow sea communication module in a low-frequency wireless mode;
when the deep sea communication module receives communication signals forwarded by other deep sea communication modules, forwarding the communication signals to the corresponding target shallow sea communication module;
and when the shallow sea communication module is used as a communication signal receiving end to communicate with the target shallow sea communication module, the shallow sea communication module receives the communication signal forwarded by the corresponding deep sea communication module.
8. The control method according to claim 7, further comprising:
the deep sea communication module determines the position of the corresponding shallow sea communication module and synchronously moves along with the corresponding shallow sea communication module so as to keep the position within a preset range from the corresponding shallow sea communication module.
9. The control method according to claim 7, wherein the shallow sea communication module and the corresponding deep sea communication module transmit communication signals therebetween by means of high-frequency wireless, cable or optical fiber.
10. The control method according to claim 7, wherein the communication signals are transmitted between the deep-sea communication modules by using an orthogonal frequency division multiplexing transmission mode.
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