Doppler estimation method and device for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots

Abstract

The present application proposes a MIMO-OFDM underwater acoustic communication Doppler estimation method and device based on multiple high-energy pilots, the method comprising: inserting multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and distributing the high-energy pilots of multiple transmission data streams at intervals; in response to the receiving end receiving a signal that has undergone frequency selective fading, dividing the in-band spectrum of the received signal into multiple intervals equal to the number of high-energy pilots; for each transmission data stream, finding the highest energy frequency point in the interval where all its high-energy pilots are located to calculate the frequency domain Doppler factor; using the relationship between the time-frequency domain stretching and compression factors, the time domain Doppler factor of the transmission data stream is calculated according to the frequency domain Doppler factor. The present application inserts multiple equally spaced high-energy pilots in the OFDM transmission data block, and uses the frequency shift of the high-energy pilots at the receiving end to inversely solve the Doppler factor, so as to achieve a large-scale low-complexity estimation of different Doppler factors for different data streams.

Description

Technical Field

[0001] The present application relates to the field of underwater acoustic communication, and in particular to a MIMO-OFDM underwater acoustic communication Doppler estimation method and device based on multiple high-energy pilots. Background Art

[0002] The ocean is the cradle of life and a huge treasure trove of resources. The development and utilization of marine resources is of great significance to alleviating the current shortage of resources and promoting the development of the national economy. In recent years, with the continuous increase of underwater application equipment, the demand for marine information transmission has increased significantly. Underwater acoustic communication is the main way of underwater medium and long-distance information transmission, and has played an important role in seabed resource detection, marine environment development, military and national defense.

[0003] MIMO-OFDM technology, which combines multi-input multi-output (MIMO) technology with orthogonal frequency-division multiplexing (OFDM) technology, can achieve extremely high communication rates by making full use of time, space and frequency resources. However, it is sensitive to the Doppler effect. When there is relative motion between transceivers, the orthogonality between subcarriers will be destroyed, resulting in inter-carrier interference (ICI), which ultimately leads to an increase in bit error rate and a decrease in communication performance. Therefore, Doppler estimation technology is very important for MIMO-OFDM underwater acoustic communication systems.

[0004] In MIMO-OFDM underwater acoustic communication, there are two commonly used Doppler estimation methods in practice. The first method is to insert hyperbolic frequency modulation (HFM) signals as leading and trailing signals at the frame header and frame tail, respectively, and estimate the Doppler factor by using the change in the relative delay of the leading and trailing signals in the received signal. However, the estimation result of this method is the average Doppler factor of the entire data frame, which cannot track the Doppler factor of each OFDM data block, and cannot distinguish the different Doppler factors of different transmitted data streams. The second method is to insert an m-sequence at the frame header, and use the m-sequence stretched and compressed by different Doppler factors to correlate with the received signal at the receiving end, and select the Doppler factor corresponding to the maximum correlation value as the estimation result. However, when the relative speed between the transceivers is large, that is, when the Doppler factor is large, this method requires a large number of correlation operations, and the amount of calculation is large. Summary of the invention

[0005] The present application aims to solve one of the technical problems in the related art at least to some extent.

[0006] To this end, the purpose of this application is to propose a MIMO-OFDM underwater acoustic communication Doppler estimation method and device based on multiple high-energy pilots, inserting multiple equally spaced high-energy pilots into an OFDM transmission data block, and using the frequency shift of the high-energy pilots at the receiving end to inversely solve the Doppler factor, thereby realizing a large range of low-complexity estimation of different Doppler factors for different data streams.

[0007] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a MIMO-OFDM underwater acoustic communication Doppler estimation method based on multiple high-energy pilots, comprising:

[0008] Insert multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and distribute the high-energy pilots of multiple transmission data streams at intervals;

[0009] In response to a receiving end receiving a signal that has undergone frequency selective fading, dividing an in-band spectrum of the received signal into a plurality of intervals equal in number to the high-energy pilot tones;

[0010] For each transmitted data stream, find the highest energy frequency point in the interval where all high-energy pilots are located, and calculate the frequency domain Doppler factor according to the highest energy frequency point and the original high-energy pilot frequency;

[0011] The relationship between the time-domain stretching and compression factors is utilized to calculate the time-domain Doppler factor of the transmitted data stream according to the frequency-domain Doppler factor.

[0012] Optionally, dividing the in-band spectrum of the received signal into a plurality of intervals equal to the number of high-energy pilots includes:

[0013]

[0014] in, Indicates interval.

[0015] Optionally, for each transmitted data stream, finding the energy highest frequency point within the interval where the high-energy pilot is located, and calculating the frequency domain Doppler factor according to the energy highest frequency point and the original high-energy pilot frequency, includes:

[0016] For The interval corresponding to all high-energy pilots of a transmitted data stream is:

[0017]

[0018] in, is the number of transmitting array elements of the MIMO system;

[0019] Assume that the received signal in frequency domain i Interval The frequency point with the highest internal energy is , for the The highest frequency point of energy in the interval where the high-energy pilot is located is recorded as , the corresponding interval is , and the corresponding high-energy pilot frequency point at the transmitting end is , then the frequency domain Doppler factor of the transmitted data stream is:

[0020]

[0021] in, is the frequency domain Doppler factor of the transmitted data stream.

[0022] Optionally, the utilizing the relationship between the time-domain stretching and compression factors and calculating the time-domain Doppler factor of the transmitted data stream according to the frequency-domain Doppler factor includes:

[0023]

[0024] in, is the time domain Doppler factor.

[0025] To achieve the above-mentioned purpose, the second embodiment of the present application proposes a MIMO-OFDM underwater acoustic communication Doppler estimation device based on multiple high-energy pilots, comprising:

[0026] A pilot pattern design module is used to insert multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and to distribute the high-energy pilots of multiple transmission data streams at intervals;

[0027] An interval division module, in response to a receiving end receiving a signal that has undergone frequency selective fading, for dividing an in-band spectrum of the received signal into a plurality of intervals equal in number to the high-energy pilot tones;

[0028] A frequency domain Doppler factor calculation module, for each transmitted data stream, is used to find the energy highest frequency point within the interval where all high-energy pilots are located, and calculate the frequency domain Doppler factor based on the energy highest frequency point and the original high-energy pilot frequency;

[0029] The time domain Doppler factor calculation module is used to calculate the time domain Doppler factor of the transmission data stream according to the frequency domain Doppler factor by utilizing the relationship between the time domain stretching and compression factors.

[0030] To achieve the above-mentioned purpose, the third aspect of the present application provides an electronic device, including: a processor, and a memory communicatively connected to the processor;

[0031] The memory stores computer-executable instructions;

[0032] The processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of the first aspects above.

[0033] To achieve the above-mentioned purpose, the fourth aspect embodiment of the present application proposes a computer-readable storage medium, in which computer execution instructions are stored. When the computer execution instructions are executed by a processor, they are used to implement the method as described in any one of the above-mentioned first aspects.

[0034] To achieve the above-mentioned purpose, the fifth aspect of the present application proposes a computer program product, including a computer program, which, when executed by a processor, implements the method as described in any one of the above-mentioned first aspects.

[0035] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0036] By inserting multiple equally spaced high-energy pilots into an OFDM transmission data block, a high-energy pilot pattern for MIMO-OFDM large-scale Doppler factor estimation is designed, which can combat a certain degree of frequency-selective fading channels; by utilizing the frequency shift of high-energy pilots of different transmission data streams at the receiving end, the Doppler factors of different transmission data streams are respectively deconstructed, thereby achieving large-scale low-complexity estimation of the Doppler factors of different transmission data streams.

[0037] In summary, the present invention proposes a MIMO-OFDM underwater acoustic communication Doppler estimation method and device based on multiple high-energy pilots, which can solve the problems that the commonly used Doppler estimation methods in practice cannot track the Doppler factor of each OFDM block, cannot distinguish the different Doppler factors of different transmitted data streams, and the amount of calculation increases with the increase of the size of the Doppler factor to be estimated.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0040] Figure 1 It is a flow chart of a Doppler estimation method for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots according to an embodiment of the present application;

[0041] Figure 2 is a schematic diagram of a pilot pattern design according to an embodiment of the present application;

[0042] Figure 3It is a block diagram of a Doppler estimation device for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots according to an embodiment of the present application;

[0043] Figure 4 It is a block diagram of an electronic device. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0045] The relative motion between transceivers in underwater acoustic communication will introduce the Doppler effect in the received signal, causing the received signal to produce stretching and compression of unknown scale, thus affecting the communication performance. In the high-speed mobile underwater acoustic MIMO-OFDM communication scenario, the two commonly used Doppler estimation methods in practice have the problems of being unable to distinguish the different Doppler factors of different transmitted data streams, being unable to track the Doppler factor of each OFDM block, and having a large amount of computation.

[0046] In response to the above problems, the present application proposes a Doppler estimation method and device for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots, which inserts multiple equally spaced high-energy pilots into an OFDM transmission data block, and uses the frequency shift of the high-energy pilots to inversely solve the Doppler factor at the receiving end, thereby achieving large-scale low-complexity estimation of different Doppler factors for different data streams.

[0047] The following describes a Doppler estimation method and device for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots in an embodiment of the present application with reference to the accompanying drawings.

[0048] Figure 1 A MIMO-OFDM underwater acoustic communication Doppler estimation method based on multiple high-energy pilots is shown according to an embodiment of the present application, such as Figure 1 As shown, the method comprises the following steps:

[0049] Step 101: insert multiple high-energy pilots at equal intervals into the subcarriers of an OFDM transmission data block, and distribute the high-energy pilots of multiple transmission data streams at intervals.

[0050] In order to design a high-energy pilot mode for MIMO-OFDM large-scale Doppler factor estimation that can resist a certain degree of frequency selective fading channels, in the embodiment of the present application, high-energy pilots with amplitudes that are preset multiples of the amplitudes of the remaining active subcarriers are inserted at equal intervals in the subcarriers of the OFDM transmission data block, and the high-energy pilots of multiple transmission data streams are distributed at intervals, wherein the first The frequency of the high-energy pilot for:

[0051]

[0052] in, is the bandwidth of the communication system, is the total number of inserted high-energy pilots, is the carrier frequency.

[0053] In one possible embodiment, the amplitude of the high-energy pilot is five times the amplitude of the remaining active subcarriers.

[0054] In another possible embodiment, assuming that there are two transmitting array elements, a total of four high-energy pilots are inserted, and the pilot frequencies are , , , , since high-energy pilots of different transmitted data streams are interspersed and inserted, , Belongs to the first transmitted data stream, , Belongs to the second transmit data stream.

[0055] It should be noted that the frequency selective fading channel is The probability that all the equally spaced high-energy pilot frequency points have large fading is small, so multiple equally spaced high-energy pilots are set to increase the probability that there is at least one high-energy pilot in the received signal, thereby ensuring the robustness of the Doppler estimation algorithm proposed in the present application to frequency selective fading channels. In addition, in order to reduce the probability that all high-energy pilots of a certain data stream are simultaneously subjected to strong fading channels, the high-energy pilots of multiple transmitted data streams are spaced and distributed.

[0056] In a possible embodiment, the schematic diagram of the pilot pattern design of the present invention is as follows: Figure 2 shown.

[0057] Step 102: In response to a receiving end receiving a signal that has undergone frequency selective fading, the in-band spectrum of the received signal is divided into a plurality of intervals equal in number to the high-energy pilots.

[0058] According to the stretching and compression properties of Fourier transform, the Doppler effect in the frequency domain is the stretching and compression in the opposite direction of the time domain, which can be modeled as follows:

[0059]

[0060]

[0061]

[0062]

[0063] in, is the frequency domain Doppler factor, is the time domain Doppler factor, is the relative speed of the transmitting and receiving ends, Indicates opposite movement. Indicates opposite motion, Indicates the speed of sound.

[0064] In order to calculate the Doppler factors of different transmitted data streams, the present application designs an estimation algorithm that uses the frequency shift and initial frequency point of the high-energy pilot to calculate the Doppler factors of different transmitted data streams.

[0065] First, when the receiving end receives a signal that has undergone frequency selective fading, the in-band spectrum of the received signal is divided into multiple intervals equal to the number of high-energy pilots, expressed as:

[0066]

[0067] in, Indicates interval.

[0068] Step 103: for each transmitted data stream, find the highest energy frequency point in the interval where all high-energy pilots are located, and calculate the frequency domain Doppler factor according to the highest energy frequency point and the original high-energy pilot frequency.

[0069] It can be understood that the Doppler factor calculation method of each specific transmission data stream is the same. An embodiment is given below, taking the Doppler factor calculation of a specific transmission data stream as an example for introduction.

[0070] For The interval corresponding to all high-energy pilots of a transmitted data stream is:

[0071]

[0072] in, is the number of transmit array elements in the MIMO system.

[0073] Referring to the embodiment mentioned in step 102, for the first transmitted data stream, the in-band spectrum of the received signal is divided into two intervals, each interval corresponding to a high-energy pilot.

[0074] Assume that the received signal in frequency domain i Interval The frequency point with the highest internal energy is , for the The highest frequency point of energy in the interval where the high-energy pilot is located is recorded as , the corresponding interval is , and the corresponding high-energy pilot frequency point at the transmitting end is , then the frequency domain Doppler factor of the transmitted data stream is:

[0075]

[0076] in, is the frequency domain Doppler factor of the transmitted data stream.

[0077] It is understandable that a transmitter The interval corresponds to In this application, the frequency points with the highest energy in the region within the interval are recorded as .

[0078] Referring to the embodiment mentioned in step 102, for the first transmitted data stream, assuming that the first interval The frequency point with the highest internal energy is , the second interval The frequency point with the highest internal energy is ,like Higher than , then for the first transmitted data stream, the energy highest frequency point in the interval where the high-energy pilot is located is ,otherwise .

[0079] Step 104: Calculate the time domain Doppler factor of the transmitted data stream according to the frequency domain Doppler factor by using the relationship between the time domain stretching and compression factors.

[0080] Finally, the relationship between the time-domain stretching and compression factors can be used to further obtain the time-domain Doppler factor of the transmitted data stream, which is expressed as follows:

[0081]

[0082] in, is the time domain Doppler factor.

[0083] Furthermore, the present invention is robust to the situation where the transmitting and receiving ends have relatively high-speed motion. The range of relative motion speed of the transmitting and receiving ends that the present invention can withstand is:

[0084]

[0085] when =8, =2, =6kHz, =1500m / s, =12kHz, ,It can be seen that the Doppler range that can be estimated by the present invention can cope with most high-speed mobile underwater acoustic MIMO-OFDM communication scenarios.

[0086] Since the present invention inserts multiple high-energy pilots for Doppler estimation into each OFDM block in the OFDM data frame, it is possible to track and estimate the Doppler factor of each OFDM block. Since the present invention inserts high-energy pilots with orthogonal frequency positions into different transmission data streams, it is possible to simultaneously estimate the different Doppler factors of different transmission data streams. Since the present invention does not need to perform correlation operations, and the amount of operations does not increase with the increase of the Doppler factor, the amount of operations is relatively low.

[0087] In summary, the present invention proposes a Doppler estimation method for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots, which can solve the problems that the commonly used Doppler estimation methods in practice cannot track the Doppler factor of each OFDM block, cannot distinguish the different Doppler factors of different transmitted data streams, and the amount of calculation increases with the increase of the size of the Doppler factor to be estimated.

[0088] In order to implement the above embodiment, the present application also proposes a MIMO-OFDM underwater acoustic communication Doppler estimation device based on multiple high-energy pilots.

[0089] Figure 3 1 is a block diagram of a MIMO-OFDM underwater acoustic communication Doppler estimation device 10 based on multiple high-energy pilots according to an embodiment of the present application, comprising:

[0090] The pilot pattern design module 100 is used to insert multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and distribute the high-energy pilots of multiple transmission data streams at intervals;

[0091] The interval division module 200 is used to divide the in-band spectrum of the received signal into a plurality of intervals equal to the number of high-energy pilots in response to the receiving end receiving the signal that has undergone frequency selective fading;

[0092] The frequency domain Doppler factor calculation module 300 is used to find the energy highest frequency point in the interval where all high-energy pilots are located for each transmitted data stream, and calculate the frequency domain Doppler factor according to the energy highest frequency point and the original high-energy pilot frequency;

[0093] The time domain Doppler factor calculation module 400 is used to calculate the time domain Doppler factor of the transmission data stream according to the frequency domain Doppler factor by utilizing the relationship between the time domain stretching and compression factors.

[0094] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0095] Figure 4 A schematic block diagram of an example electronic device 700 that can be used to implement an embodiment of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described and / or required herein.

[0096] like Figure 4 As shown, the device 700 includes a computing unit 701, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 702 or a computer program loaded from a storage unit 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the device 700 can also be stored. The computing unit 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0097] A number of components in the device 700 are connected to the I / O interface 705, including: an input unit 706, such as a keyboard, a mouse, etc.; an output unit 707, such as various types of displays, speakers, etc.; a storage unit 708, such as a disk, an optical disk, etc.; and a communication unit 709, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 709 allows the device 700 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0098] The computing unit 701 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 701 performs the various methods and processes described above, such as the voice instruction response method. For example, in some embodiments, the voice instruction response method may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 708. In some embodiments, part or all of the computer program may be loaded and / or installed on the device 700 via the ROM 702 and / or the communication unit 709. When the computer program is loaded into the RAM 703 and executed by the computing unit 701, one or more steps of the voice instruction response method described above may be performed. Alternatively, in other embodiments, the computing unit 701 may be configured to perform the voice instruction response method in any other appropriate manner (e.g., by means of firmware).

[0099] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0100] The program code for implementing the method of the present application can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, implements the functions / operations specified in the flow chart and / or block diagram. The program code can be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0101] In the context of the present application, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0102] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0103] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), the Internet, and a blockchain network.

[0104] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship between the client and the server is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services ("Virtual Private Server", or "VPS" for short). The server may also be a server of a distributed system, or a server combined with a blockchain.

[0105] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in this application can be executed in parallel, sequentially or in different orders, as long as the expected results of the technical solution of this application can be achieved, and this document is not limited here.

[0106] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A Doppler estimation method for MIMO-OFDM underwater acoustic communication based on multiple high-energy pilots, characterized in that: include: Insert multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and distribute the high-energy pilots of multiple transmission data streams at intervals; In response to a receiving end receiving a signal that has undergone frequency selective fading, dividing an in-band spectrum of the received signal into a plurality of intervals equal in number to the high-energy pilot tones; For each transmitted data stream, find the highest energy frequency point in the interval where all high-energy pilots are located, and calculate the frequency domain Doppler factor according to the highest energy frequency point and the original high-energy pilot frequency; The relationship between the time-domain stretching and compression factors is utilized to calculate the time-domain Doppler factor of the transmission data stream according to the frequency-domain Doppler factor.

2. The method according to claim 1, characterized in that The method inserts a plurality of high-energy pilots at equal intervals into the subcarriers of an OFDM transmission data block, and distributes the high-energy pilots of a plurality of transmission data streams at intervals, including: In the subcarriers of the OFDM transmission data block, high-energy pilots with amplitudes that are preset multiples of the amplitudes of the remaining active subcarriers are inserted at equal intervals, and the high-energy pilots of multiple transmission data streams are distributed at intervals, wherein the first The frequency of the high-energy pilot for: in, is the bandwidth of the communication system, is the total number of inserted high-energy pilots, is the carrier frequency.

3. The method according to claim 2, characterized in that The step of dividing the in-band spectrum of the received signal into a plurality of intervals equal in number to the high-energy pilot tones comprises: in, Indicates interval.

4. The method according to claim 3, characterized in that For each transmitted data stream, finding the highest energy frequency point within the interval where the high energy pilot frequency is located, and calculating the frequency domain Doppler factor according to the highest energy frequency point and the original high energy pilot frequency, including: For The interval corresponding to all high-energy pilots of a transmitted data stream is: in, is the number of transmitting array elements of the MIMO system; Assume that the received signal in frequency domain i Interval The frequency point with the highest internal energy is , for the The highest frequency point of energy in the interval where the high-energy pilot is located is recorded as , the corresponding interval is , and the corresponding high-energy pilot frequency point at the transmitting end is , then the frequency domain Doppler factor of the transmitted data stream is: in, is the frequency domain Doppler factor of the transmitted data stream.

5. The method according to claim 4, characterized in that The method of calculating the time domain Doppler factor of the transmitted data stream according to the frequency domain Doppler factor by utilizing the relationship between the time domain stretching and compression factors includes: in, is the time domain Doppler factor.

6. A MIMO-OFDM underwater acoustic communication Doppler estimation device based on multiple high-energy pilots, characterized in that: include: A pilot pattern design module is used to insert multiple high-energy pilots at equal intervals in the subcarriers of an OFDM transmission data block, and to distribute the high-energy pilots of multiple transmission data streams at intervals; An interval division module, in response to a receiving end receiving a signal that has undergone frequency selective fading, for dividing an in-band spectrum of the received signal into a plurality of intervals equal in number to the high-energy pilot tones; A frequency domain Doppler factor calculation module, for each transmitted data stream, is used to find the energy highest frequency point within the interval where all high-energy pilots are located, and calculate the frequency domain Doppler factor based on the energy highest frequency point and the original high-energy pilot frequency; The time domain Doppler factor calculation module is used to calculate the time domain Doppler factor of the transmission data stream according to the frequency domain Doppler factor by utilizing the relationship between the time domain stretching and compression factors.

7. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 5 when executed by a processor.

9. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 5 when being executed by a processor.

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