Signal processing method and device for underwater acoustic communication, computer equipment and storage medium

Abstract

The invention relates to a signal processing method and device for underwater acoustic communication, computer equipment and a storage medium. The method comprises the following steps: acquiring original underwater acoustic channel data; based on a preset underwater acoustic channel parameter, converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal; adding a dynamic cyclic prefix in the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with the cyclic prefix; inserting a preset pilot signal into the orthogonal frequency division multiplexing signal with the cyclic prefix, and performing channel estimation by using the preset pilot signal to obtain a channel estimation result; judging whether the channel estimation result meets a preset requirement or not; and if the channel estimation result meets a preset requirement, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with the cyclic prefix to obtain a target orthogonal frequency division multiplexing signal. Therefore, the method can effectively suppress the inter-carrier interference, reduce the bit error rate, and improve the signal recovery precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater acoustic communication, and particularly relates to a signal processing method and device for underwater acoustic communication, a computer device and a storage medium. BACKGROUND

[0002] Underwater acoustic communication is a key means for underwater information transmission. Due to the influence of a complex marine environment, underwater acoustic channels are prone to problems such as long transmission delay, severe multipath effect, Doppler spread and limited bandwidth, which result in serious frequency-selective fading and time-selective fading of signals in the transmission process, and affect the stability and transmission rate of communication.

[0003] Although traditional equalization algorithms can counter the multipath effect and other channel distortion problems to some extent, due to the high complexity of the traditional equalization algorithms, it is difficult to adapt to the dynamic changes of underwater acoustic channels, and thus the recovery effect of underwater acoustic communication signals is poor and the bit error rate is high. SUMMARY

[0004] Embodiments of the present application provide a signal processing method and device for underwater acoustic communication, a computer device and a storage medium, aiming at solving the problem that the recovery effect of underwater acoustic communication signals is poor and the bit error rate is high due to the high complexity of traditional equalization algorithms, which makes it difficult to adapt to the dynamic changes of underwater acoustic channels.

[0005] In a first aspect, the embodiments of the present application provide a signal processing method for underwater acoustic communication, and the signal processing of the underwater acoustic communication method comprises:

[0006] obtaining original underwater acoustic channel data;

[0007] converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters;

[0008] adding a dynamic cyclic prefix to the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix;

[0009] inserting a preset pilot signal into the orthogonal frequency division multiplexing signal with a cyclic prefix, performing channel estimation using the preset pilot signal, and obtaining a channel estimation result;

[0010] judging whether the channel estimation result meets a preset requirement;

[0011] if the channel estimation result meets the preset requirement, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

[0012] In some possible implementation manners, the Doppler compensation is two-step Doppler compensation, including hyperbolic frequency modulation coarse synchronization and pilot fine synchronization, the Doppler compensation processing and the frequency domain equalization processing are performed on the OFDM signal with a cyclic prefix to obtain a target OFDM signal, and the method comprises the following steps of:

[0013] Hyperbolic frequency modulation coarse synchronization is performed on the target OFDM signal to obtain a first compensation OFDM signal.

[0014] Pilot fine synchronization is performed on the first compensation OFDM signal to obtain a second compensation OFDM signal.

[0015] The frequency domain equalization processing is performed on the second compensation OFDM signal to obtain the target OFDM signal.

[0016] In some possible implementation manners, the frequency domain equalization processing is performed on the second compensation OFDM signal to obtain the target OFDM signal, and the method comprises the following steps of:

[0017] The second compensation OFDM signal is filtered to obtain a filtered second compensation OFDM signal.

[0018] The filtered second compensation OFDM signal is iteratively decoded and recovered to obtain the target OFDM signal.

[0019] In some possible implementation manners, after the target OFDM signal is obtained, the method further comprises the following steps of:

[0020] It is judged whether the bit error rate of the target OFDM signal is lower than a preset bit error rate.

[0021] If the bit error rate of the target OFDM signal is lower than or equal to the preset bit error rate, the target OFDM signal is output.

[0022] In some possible implementation manners, the judgment of whether the bit error rate of the target OFDM signal is lower than a preset bit error rate further comprises the following steps of:

[0023] If the bit error rate of the target OFDM signal is higher than the preset bit error rate, an equalization parameter is adjusted or an iteration number is increased, and the frequency domain equalization processing operation is re-executed.

[0024] In some possible implementation manners, the judgment of whether the channel estimation result meets a preset requirement further comprises the following steps of:

[0025] If the channel estimation result does not meet the preset requirement, a pilot density is adjusted and / or a preset sparse reconstruction algorithm is used to re-perform channel estimation.

[0026] In some possible implementation manners, the converting the original underwater acoustic channel data into the OFDM signal based on the preset underwater acoustic channel parameter comprises:

[0027] The original underwater acoustic channel data is converted into parallel underwater acoustic channel data based on the preset underwater acoustic channel parameter;

[0028] The parallel underwater acoustic channel data is subjected to subcarrier mapping and modulation to obtain modulated subcarrier data;

[0029] The modulated subcarrier data is subjected to inverse fast Fourier transform to obtain the OFDM signal.

[0030] In a second aspect, an embodiment of the present application further provides a signal processing apparatus for underwater acoustic communication, which comprises units for executing the above method.

[0031] In a third aspect, an embodiment of the present application further provides a computer device, which comprises a memory and a processor, the memory stores a computer program, and the processor implements the above method when executing the computer program.

[0032] In a fourth aspect, an embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the computer program can implement the above method when being executed by a processor.

[0033] Embodiments of the present application provide a signal processing method, apparatus, computer device and storage medium for underwater acoustic communication. The method comprises: obtaining original underwater acoustic channel data; converting the original underwater acoustic channel data into an OFDM signal based on a preset underwater acoustic channel parameter; adding a dynamic cyclic prefix in the OFDM signal to obtain an OFDM signal with a cyclic prefix; inserting a preset pilot signal in the OFDM signal with the cyclic prefix, performing channel estimation by using the preset pilot signal to obtain a channel estimation result; determining whether the channel estimation result meets a preset requirement; and if the channel estimation result meets the preset requirement, performing Doppler compensation processing and frequency domain equalization processing on the OFDM signal with the cyclic prefix to obtain a target OFDM signal.

[0034] The embodiment of the present application can effectively counter the inter-symbol interference and inter-carrier interference caused by the multipath effect by adding a dynamic cyclic prefix in the OFDM signal, improve the spectrum utilization, and more accurately obtain the state information of the time-varying underwater acoustic channel by inserting a preset pilot signal and performing channel estimation based on the pilot signal, thereby providing a reliable basis for subsequent receiver processing. After the channel estimation result meets the preset requirement, the signal is subjected to joint processing of Doppler compensation and frequency domain equalization, which can effectively cope with the time-selective fading and frequency-selective fading problems in the underwater acoustic channel, effectively suppress error propagation, improve the accuracy of signal processing, and the frequency domain equalization processing can effectively suppress the inter-carrier interference, reduce the bit error rate, and improve the signal recovery accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0037] One or more embodiments are exemplarily illustrated by the pictures in the drawings corresponding thereto, and these exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings in the drawings do not constitute a proportional limitation.

[0038] Figure 1 A flowchart of a first embodiment of a signal processing method for underwater acoustic communication provided by the present application is shown in the figure.

[0039] Figure 2 A structural schematic diagram of a computer device provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0041] The disclosure below provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity, the description below of the specific examples refers only to the described embodiments. It is not intended to limit the present application to these embodiments, which are presented for illustrative purposes. Furthermore, the described embodiments are not intended to be mutually exclusive, unless explicitly stated otherwise. Moreover, the present application can be implemented in various examples using different examples of the components and / or arrangements described. Such variations are not to be regarded as a departure from the scope of the present application, and all examples are contemplated in the scope of the present application.

[0042] It should be understood that the terms "comprises" and "comprising," when used in this specification and the following claims, indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0043] It should also be understood that the terms used in the present specification and the following claims are merely for the purpose of describing particular embodiments, and are not intended to limit the present application. As used in the present specification and the following claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0044] It should further be understood that the term "and / or" used in the present specification and the following claims, means one or more of the associated listed items, as well as all possible combinations of the items.

[0045] As used in the present specification and the following claims, the term "if' can be interpreted as meaning "when" or "once" or "in response to a determination" or "in response to a detection" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted as meaning "once determined" or "in response to a determination" or "once detected [the described condition or event]" or "in response to a detection [the described condition or event]" depending on the context.

[0046] The technical bottleneck of underwater acoustic communication systems is essentially due to the fundamental contradiction between the physical characteristics of underwater acoustic wave propagation and existing signal processing schemes. Due to the fact that the speed of sound wave propagation in water medium is only about 1500 m / s, combined with the complex and changeable underwater environment, there are significant multipath reflection and Doppler effect, which leads to serious time delay spread, frequency selective fading and time selective fading, etc. These channel inherent characteristics have three key influences on system performance:

[0047] First, the orthogonal frequency division multiplexing (OFDM) signal has a high peak-to-average power ratio (PAPR), which is easy to introduce nonlinear distortion in the power amplification process, seriously affecting the energy efficiency of the system;

[0048] Secondly, the fixed length of the cyclic prefix (CP) design in the conventional OFDM system is difficult to adapt to the dynamic change of the multipath time delay spread in the underwater acoustic channel, causing waste of spectrum resources and reducing the spectrum utilization rate;

[0049] Thirdly, the current widely used static pilot insertion mode cannot effectively track the rapid time-varying characteristics of the underwater acoustic channel, resulting in rapid decline in channel estimation accuracy, and further affecting the subsequent demodulation and equalization effect.

[0050] From the signal processing architecture level, the existing technical solutions also have obvious systematic defects. The traditional receiver generally adopts a serial linear processing chain structure, and the Doppler compensation, channel estimation and equalization modules are connected in series. This design method causes the estimation error between modules to be continuously transmitted and accumulated, which seriously affects the overall performance of the system. More seriously, the Doppler compensation and equalization processing processes are independent of each other, lack of joint optimization mechanism, causing algorithm redundancy, not only increasing the calculation complexity, but also reducing the real-time response ability of the system.

[0051] In terms of specific algorithm implementation, the existing solutions face many trade-off dilemmas: on the one hand, high-precision channel estimation algorithms often come with high computational cost; on the other hand, the design of the equalizer needs to be compromised between convergence speed and steady-state error. These technical difficulties jointly restrict the reliability and data transmission rate of the current underwater acoustic communication system in complex marine environments.

[0052] In order to solve the above problems, the present application provides a signal processing device for underwater acoustic communication, which can effectively suppress inter-carrier interference, reduce bit error rate and improve signal recovery accuracy.

[0053] Referring to Figure 1 , Figure 1 The flowchart of the first embodiment of the signal processing method for underwater acoustic communication provided by the present application is shown. The signal processing of the underwater acoustic communication method comprises the following steps:

[0054] Step 110: obtaining original underwater acoustic channel data.

[0055] Step 120: converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters.

[0056] Step 130: adding a dynamic cyclic prefix to the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix.

[0057] Step 140: inserting a preset pilot signal into the orthogonal frequency division multiplexing signal with a cyclic prefix, and using the preset pilot signal for channel estimation to obtain a channel estimation result.

[0058] Step 150: judging whether the channel estimation result meets the preset requirement.

[0059] Step 160: if the channel estimation result meets the preset requirement, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

[0060] The embodiment can effectively resist the inter-symbol interference and inter-carrier interference caused by the multipath effect by adding the dynamic cyclic prefix in the orthogonal frequency division multiplexing signal, improve the spectrum utilization, obtain the state information of the time-varying underwater acoustic channel more accurately by inserting the preset pilot signal and performing channel estimation based on the pilot signal, thereby providing a reliable basis for the subsequent receiving end processing, perform the joint processing of Doppler compensation and frequency domain equalization on the signal after the channel estimation result meets the preset requirement, effectively cope with the time selective fading and frequency selective fading problems in the underwater acoustic channel, effectively suppress the error propagation, improve the accuracy of the signal processing, and the frequency domain equalization processing can effectively suppress the inter-carrier interference, reduce the bit error rate, and improve the signal recovery accuracy.

[0061] In some possible implementation manners, the Doppler compensation is two-step Doppler compensation including hyperbolic frequency modulation coarse synchronization and pilot fine synchronization, and the performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with cyclic prefix to obtain a target orthogonal frequency division multiplexing signal includes:

[0062] Step 161: performing hyperbolic frequency modulation coarse synchronization on the target orthogonal frequency division multiplexing signal to obtain a first compensation orthogonal frequency division multiplexing signal.

[0063] Step 162: performing pilot fine synchronization on the first compensation orthogonal frequency division multiplexing signal to obtain a second compensation orthogonal frequency division multiplexing signal.

[0064] Step 163: performing frequency domain equalization processing on the second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal.

[0065] In some possible implementation manners, the performing frequency domain equalization processing on the second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal, namely step 163, includes:

[0066] Step 1631: performing filtering processing on the second compensation orthogonal frequency division multiplexing signal to obtain a filtered second compensation orthogonal frequency division multiplexing signal.

[0067] Step 1632: performing iterative decoding recovery on the filtered second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal.

[0068] Referring to a second embodiment of a signal processing method of underwater acoustic communication provided by the present application, the signal processing of the underwater acoustic communication method comprises the following steps:

[0069] Step 210: obtaining original underwater acoustic channel data.

[0070] Step 220: converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters.

[0071] Step 230: adding a dynamic cyclic prefix in the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix.

[0072] Step 240: inserting a preset pilot signal in the orthogonal frequency division multiplexing signal with a cyclic prefix, performing channel estimation by using the preset pilot signal to obtain a channel estimation result.

[0073] Step 250: judging whether the channel estimation result meets preset requirements.

[0074] Step 260: if the channel estimation result meets the preset requirements, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

[0075] In some possible implementation manners, if the channel estimation result does not meet the preset requirements, the pilot density is adjusted and / or the channel estimation is re-performed by using a preset sparse reconstruction algorithm.

[0076] Step 270: judging whether the bit error rate of the target orthogonal frequency division multiplexing signal is lower than a preset bit error rate.

[0077] Step 280: if the bit error rate of the target orthogonal frequency division multiplexing signal is lower than or equal to the preset bit error rate, outputting the target orthogonal frequency division multiplexing signal.

[0078] Step 290: if the bit error rate of the target orthogonal frequency division multiplexing signal is higher than the preset bit error rate, adjusting an equalization parameter or increasing an iteration number, and re-executing the frequency domain equalization processing operation.

[0079] Referring to a third embodiment of a signal processing method of underwater acoustic communication provided by the present application, the signal processing of the underwater acoustic communication method comprises the following steps:

[0080] Step 310: obtaining original underwater acoustic channel data.

[0081] Step 320: performing serial-parallel conversion on the original underwater acoustic channel data based on preset underwater acoustic channel parameters to obtain parallel underwater acoustic channel data.

[0082] Step 330: subcarrier mapping and modulation are performed on the parallel underwater acoustic channel data to obtain modulated subcarrier data.

[0083] Step 340: inverse fast Fourier transform is performed on the modulated subcarrier data to obtain an orthogonal frequency division multiplexing signal.

[0084] Step 350: a dynamic cyclic prefix is added to the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix.

[0085] Step 360: a preset pilot signal is inserted into the orthogonal frequency division multiplexing signal with a cyclic prefix, and channel estimation is performed by using the preset pilot signal to obtain a channel estimation result.

[0086] Step 370: it is judged whether the channel estimation result meets a preset requirement.

[0087] Step 380: if the channel estimation result meets the preset requirement, Doppler compensation processing and frequency domain equalization processing are performed on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

[0088] Based on the above embodiment, the signal processing method for underwater acoustic communication provided in the application mainly adopts a MIMO system and a single-antenna OFDM system to process the modeling result after modeling the underwater acoustic channel, wherein the single-antenna OFDM system mainly adopts a peak-to-average ratio suppression technology and a frequency offset estimation technology in a Doppler environment, and the MIMO system mainly adopts a frequency band division technology, a combination technology of a time reversal mirror and a decision feedback equalization, a frequency domain decision feedback Turbo equalization technology and a precoding technology. For details, refer to the following specific description.

[0089] (1) Underwater acoustic channel characteristic analysis and channel modeling

[0090] Due to the particularity of the medium and transmission carrier, the underwater acoustic channel, especially the underwater acoustic channel used for medium distance (1-10 km) transmission, shows great specificity compared with the wireless communication channel. These specificities mainly include the following five aspects: 1) a strictly limited channel caused by sound absorption effect, sound propagation attenuation and strong sound scattering; 2) strong fluctuation characteristics of underwater acoustic signals; 3) specificity of sound field and multipath; 4) large Doppler characteristics caused by small sound velocity; and 5) specificity of background noise. These specificities determine the channel characteristics of long delay, rich multipath components, serious Doppler spread and limited transmission bandwidth, which are key problems that need to be faced in realizing high-speed and reliable underwater acoustic communication.

[0091] (2) Single-antenna orthogonal frequency division multiplexing system and equalization technology thereof

[0092] Among them, the single antenna orthogonal frequency division multiplexing system and its equalization technology can include the following:

[0093] 1) By converting the high-speed serial data stream into a low-speed parallel data stream through serial-parallel conversion for transmission, each sub-band is relatively flat, thereby effectively resisting the underwater acoustic multipath effect, reducing the complexity of the receiver equalization part, and conveniently introducing a cyclic prefix. The cyclic prefix can not only reduce or even eliminate inter-symbol interference and inter-carrier interference, but also reduce the requirement for synchronization accuracy of the system.

[0094] 2) Orthogonality exists between each subcarrier, and the subchannel spectrum overlaps each other, the frequency band resource is fully utilized, and it is suitable for underwater acoustic channels with limited spectrum resources.

[0095] 3) Modulation and demodulation can be realized through IFFT / FFT, and the processing rate is improved.

[0096] 4) Frequency domain equalization can be easily realized by inserting a frequency domain pilot.

[0097] 5) It can be easily combined with other multiple access methods, and asymmetric high-speed data transmission can be realized. At the same time, OFDM has a variable bandwidth, and the system bandwidth is flexibly adjusted through the number of subcarriers.

[0098] Based on the existing OFDM technology, by introducing the estimation of the Doppler spread, a fast and stable synchronization algorithm is studied to realize fast acquisition and stable tracking of the signal, realize data frame start position estimation, Doppler factor estimation and carrier frequency offset estimation. At the same time, the application of compressed sensing method for quasi-static channel estimation can save bandwidth resources on the premise of improving system performance.

[0099] (3) MIMO system and its equalization technology

[0100] With the proposal of multiple-input multiple-output (MIMO) technology, in the transmission dimension of time and frequency, there is also a transmission degree of freedom in space. Compared with single-input single-output (SISO) system, MIMO technology can improve channel capacity and obtain diversity gain. The bandwidth of underwater acoustic channel is limited, and after applying MIMO technology, the actual transmission rate of the system is expected to be greatly improved.

[0101] In the MIMO system using spatial multiplexing system and multi-channel equalizer, the data to be transmitted is divided into several transmission streams at the transmitting end, each transmission stream corresponds to a transmitting transducer. Each transmission stream is independently encoded, constellation mapped, and then transmitted.

[0102] MIMO system introduces Co-Channel Interference (CCI) in the parallel data streams of multiple transmitters. At the receiving end, the receiving hydrophone array is fully utilized, and a multi-channel equalizer is used to recover the transmitted signals.

[0103] (4) Sub-band technology

[0104] The sub-band technology refers to dividing a relatively wide communication frequency band into a plurality of sub-bands during coding, and performing data modulation on each sub-band, respectively. A certain guard band is inserted between each sub-band, so that there is no interference between the sub-bands at the receiving end. Due to the severe time delay spread of the underwater acoustic channel, the filter order in the decision feedback equalization is very high, which increases the complexity of the system. The time reversal mirror technology cannot completely eliminate the inter-symbol interference in the equalization process.

[0105] In view of the shortcomings of the two equalization methods, the time reversal mirror technology is combined with the decision feedback equalization in the present application. The decision feedback equalization is used to overcome the residual inter-symbol interference after the time reversal processing, and the time reversal mirror technology is used to reduce the number of delay elements of the decision feedback equalizer. The two methods promote each other, and the communication quality of the system under the multi-path condition is improved.

[0106] The performance of underwater acoustic communication can be improved by introducing redundant information in the transmission process through channel coding. In the traditional receiver design, equalization and channel decoding are processed as two independent modules. When the inter-symbol interference is very serious, there is still strong interference in the equalizer output, and the effect of channel decoding needs to be improved. Turbo equalization, which iteratively processes between equalization and decoding, can improve the performance of the communication system in the multi-path channel. Turbo equalization draws on the idea of concatenated codes, uses the channel coding used in the communication system as an outer code, and uses the transmission channel as an outer code. By transmitting soft information between the equalizer and the decoder, iterative processing is performed for signal recovery. In a channel with very serious inter-symbol interference, Turbo equalization can significantly improve the performance of transmission by iteratively performing soft decoding and equalization algorithms.

[0107] In addition, frequency domain Turbo equalization can further reduce the processing complexity of Turbo equalization. When the channel length is large, time domain Turbo equalization needs to invert a large matrix to calculate the filter coefficients, which makes the calculation complexity very high. Therefore, with the help of the time-frequency transformation of FFT and IFFT, the filter coefficients of Turbo equalization can be quickly solved in the frequency domain. Forward filtering and feedback filtering are performed on the received signal and the feedback signal in the frequency domain. The frequency domain Turbo algorithm based on decision feedback significantly reduces the complexity of coefficient calculation and filtering processing, while obtaining a performance close to that of time domain Turbo equalization.

[0108] (5) Precoding technology.

[0109] By using the precoding technology, the input signal of the transmitting transducer is pre-weighted according to the underwater acoustic channel, and then the generalized flat channel transmission is realized.

[0110] Based on the above embodiments, the signal processing method for underwater acoustic communication provided by the application mainly includes the following processes:

[0111] 1) initializing the underwater acoustic channel parameters;

[0112] The underwater acoustic channel parameters can include but are not limited to multipath delay, Doppler factor and bandwidth.

[0113] 2) obtaining original underwater acoustic channel data;

[0114] The original underwater acoustic channel data is a high-speed serial data stream.

[0115] 3) generating an OFDM sending signal, i.e. converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on the preset underwater acoustic channel parameters;

[0116] Specifically, it can include the following steps:

[0117] 3-1) converting the high-speed serial data stream into a plurality of low-speed parallel subcarriers (i.e. parallel underwater acoustic channel data) for transmission through serial-parallel conversion;

[0118] 3-2) performing subcarrier mapping and modulation on the parallel underwater acoustic channel data to obtain modulated subcarrier data;

[0119] 3-3) performing inverse fast Fourier transform on the modulated subcarrier data to obtain an orthogonal frequency division multiplexing signal.

[0120] In this way, the orthogonality between subcarriers can be used to improve the spectrum utilization.

[0121] In addition, the generated OFDM sending signal is encoded before adding a dynamic cyclic prefix.

[0122] 4) adding a dynamic cyclic prefix to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix;

[0123] 5) inserting a preset pilot signal, using the preset pilot signal for channel estimation to obtain a channel estimation result;

[0124] 6) determining whether the channel estimation result is accurate;

[0125] If yes, 7-1) is executed, and if no, 7-2) is executed.

[0126] 7-1) performing two-step Doppler compensation;

[0127] wherein the two-step Doppler compensation comprises HFM coarse synchronization and pilot fine synchronization.

[0128] 7-2) adjusting pilot density and sparse reconstruction algorithm, returning to perform 4).

[0129] 8) performing frequency domain Turbo equalization processing;

[0130] wherein the frequency domain Turbo equalization processing comprises MMSE filtering and LDPC iterative decoding.

[0131] 9) judging whether the decoded bit error rate meets the standard;

[0132] if yes, performing 10), and if no, performing 11).

[0133] 10) outputting the recovered binary data stream.

[0134] 11) optimizing equalization parameters or increasing the number of iterations, returning to perform 8).

[0135] Thus, the application adopts orthogonal frequency division multiplexing technology, converts high-speed serial data stream into multiple low-speed parallel subcarriers for transmission, utilizes the orthogonality between subcarriers to improve spectral efficiency, and effectively counteracts inter-symbol interference (ISI) and inter-carrier interference (ICI) caused by multipath effect by inserting cyclic prefix (CP).

[0136] In addition, the channel estimation and equalization technology based on frequency domain pilot greatly reduces the implementation complexity of the receiver.

[0137] At the channel adaptation level, through the construction of a time-frequency-space three-dimensional joint perception system, all-around cognition of the underwater acoustic channel is realized; a dynamic cyclic prefix adjustment mechanism based on channel prediction is developed, which significantly improves the spectral efficiency. At the signal processing level, a joint channel estimation algorithm assisted by deep prior is designed, which breaks through the precision limit of traditional methods; a collaborative optimization framework of Doppler parameters and equalization parameters is established, which effectively suppresses error propagation. In terms of system architecture, cross-layer optimization design is innovatively adopted, which breaks through the information barrier between the physical layer and the protocol layer; heterogeneous computing acceleration technology is introduced to ensure real-time execution of complex algorithms.

[0138] Corresponding to the above signal processing method of underwater acoustic communication, the application further provides a signal processing device of underwater acoustic communication. The signal processing device of underwater acoustic communication comprises a unit for executing the above signal processing method of underwater acoustic communication, and the signal processing device of underwater acoustic communication can be configured in a desktop computer, a tablet computer, a laptop computer, and the like terminal.

[0139] As Figure 2As shown, the embodiment of the present application provides a computer device, comprising a processor 111, a communication interface 112, a memory 113 and a communication bus 114, wherein the processor 111, the communication interface 112 and the memory 113 complete mutual communication through the communication bus 114,

[0140] The memory 113 is used for storing a computer program.

[0141] In an embodiment of the present application, the processor 111 is used for executing the program stored in the memory 113, and a signal processing method for underwater acoustic communication provided by any one of the foregoing method embodiments is realized, comprising:

[0142] Obtaining original underwater acoustic channel data;

[0143] Converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters;

[0144] Adding a dynamic cyclic prefix in the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix;

[0145] Inserting a preset pilot signal in the orthogonal frequency division multiplexing signal with a cyclic prefix, performing channel estimation by using the preset pilot signal to obtain a channel estimation result;

[0146] Judging whether the channel estimation result meets preset requirements;

[0147] If the channel estimation result meets the preset requirements, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

[0148] Those skilled in the art can understand that all or part of the processes in the method for implementing the above embodiment can be completed by a computer program instructing related hardware. The computer program can be stored in a storage medium, which is a computer readable storage medium. The computer program is executed by at least one processor in the computer system to implement the process steps of the above method embodiment.

[0149] Therefore, the embodiment of the present application further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the signal processing method for underwater acoustic communication provided by any one of the foregoing method embodiments, comprising:

[0150] Obtaining original underwater acoustic channel data;

[0151] Converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters;

[0152] adding a dynamic cyclic prefix in the OFDM signal to obtain an OFDM signal with a cyclic prefix;

[0153] inserting a preset pilot signal in the OFDM signal with a cyclic prefix, performing channel estimation by using the preset pilot signal to obtain a channel estimation result;

[0154] judging whether the channel estimation result meets a preset requirement;

[0155] if the channel estimation result meets the preset requirement, performing Doppler compensation processing and frequency domain equalization processing on the OFDM signal with a cyclic prefix to obtain a target OFDM signal.

[0156] The storage medium is an entity, non-transient storage medium, for example, can be a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a magnetic disk or an optical disk, and various entity storage media that can store program codes. The computer readable storage medium can be non-volatile or volatile.

[0157] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0158] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be realized by other ways. For example, the device embodiments described above are only schematic. For example, the division of each unit is only a logical function division, and actual implementation can have another division manner. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0159] The steps in the method embodiments of the present application can be adjusted, combined and deleted according to actual needs. The units in the device embodiments of the present application can be combined, divided and deleted according to actual needs. In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit.

[0160] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a storage medium. Based on such understanding, the technical solutions of the present application essentially or say the part that contributes to the prior art, or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a terminal, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application.

[0161] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0162] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, any modifications and variations of the present application that fall within the scope of the claims of the present application and their equivalent technologies shall be included in the scope of the present application.

[0163] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any modifications or replacements that those skilled in the art can easily think of within the technical scope disclosed by the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A signal processing method for underwater acoustic communication, characterized by, The signal processing method of the underwater acoustic communication comprises the following steps: obtaining original underwater acoustic channel data; converting the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters; adding a dynamic cyclic prefix to the orthogonal frequency division multiplexing signal to obtain an orthogonal frequency division multiplexing signal with a cyclic prefix; inserting a preset pilot signal into the orthogonal frequency division multiplexing signal with a cyclic prefix, performing channel estimation using the preset pilot signal, and obtaining a channel estimation result; judging whether the channel estimation result meets preset requirements; if the channel estimation result meets preset requirements, performing Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal.

2. The method of claim 1, wherein, The Doppler compensation is two-step Doppler compensation, including hyperbolic frequency modulation coarse synchronization and pilot fine synchronization. The Doppler compensation processing and frequency domain equalization processing on the orthogonal frequency division multiplexing signal with a cyclic prefix to obtain a target orthogonal frequency division multiplexing signal comprises the following steps: performing hyperbolic frequency modulation coarse synchronization on the target orthogonal frequency division multiplexing signal to obtain a first compensation orthogonal frequency division multiplexing signal; performing pilot fine synchronization on the first compensation orthogonal frequency division multiplexing signal to obtain a second compensation orthogonal frequency division multiplexing signal; performing frequency domain equalization processing on the second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal.

3. The method of claim 2, wherein, The frequency domain equalization processing on the second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal comprises the following steps: performing filtering processing on the second compensation orthogonal frequency division multiplexing signal to obtain filtered second compensation orthogonal frequency division multiplexing signal; performing iterative decoding recovery on the filtered second compensation orthogonal frequency division multiplexing signal to obtain a target orthogonal frequency division multiplexing signal.

4. The method of claim 1, wherein, After obtaining the target orthogonal frequency division multiplexing signal, the method further comprises the following steps: judging whether the bit error rate of the target orthogonal frequency division multiplexing signal is lower than a preset bit error rate; if the bit error rate of the target orthogonal frequency division multiplexing signal is lower than or equal to the preset bit error rate, outputting the target orthogonal frequency division multiplexing signal.

5. The method of claim 4, wherein, The judgment of whether the bit error rate of the target orthogonal frequency division multiplexing signal is lower than a preset bit error rate further comprises the following steps: if the bit error rate of the target orthogonal frequency division multiplexing signal is higher than the preset bit error rate, adjusting an equalization parameter or increasing an iteration number, and re-executing the frequency domain equalization processing operation.

6. The method of claim 1, wherein, The judgment of whether the channel estimation result meets preset requirements further comprises the following steps: if the channel estimation result does not meet preset requirements, adjusting a pilot density and / or re-performing channel estimation using a preset sparse reconstruction algorithm.

7. The method of claim 1, wherein, The conversion of the original underwater acoustic channel data into an orthogonal frequency division multiplexing signal based on preset underwater acoustic channel parameters comprises the following steps: performing serial-parallel conversion on the original underwater acoustic channel data based on preset underwater acoustic channel parameters to obtain parallel underwater acoustic channel data; performing subcarrier mapping and modulation on the parallel underwater acoustic channel data to obtain modulated subcarrier data; performing inverse fast Fourier transform on the modulated subcarrier data to obtain an orthogonal frequency division multiplexing signal.

8. A signal processing device for underwater acoustic communication, characterized by The computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method according to any one of claims 1-7.

9. A computer device, comprising: The storage medium stores a computer program, and the computer program, when executed by a processor, can implement the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, ​

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