Underwater communication and positioning integrated waveform design method

Abstract

The invention relates to the technical field of underwater communication and positioning, discloses an underwater communication and positioning integrated waveform design method, and aims to optimize the communication and positioning performance of underwater equipment through fusion design. According to the method, a sparse vector coding matrix technology is utilized, the dimension of a sparse signal is reduced into a transmittable modulation symbol, and an integrated waveform is generated by means of inverse discrete Fourier transform (IFFT). The integrated waveform not only has good communication reliability, but also has an excellent self-correlation characteristic, and is suitable for an underwater communication positioning integrated system. According to the technical scheme, the method comprises the key steps of sparse vector mapping, coding matrix dimensionality reduction, pilot frequency generation and insertion, IFFT waveform generation and the like, the joint performance of the underwater communication and positioning integrated system in the changeable marine environment is effectively improved, and the performance of underwater acoustic digital communication and underwater target positioning is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of underwater communication and positioning technology, and in particular to a waveform design method for underwater communication and positioning integration. Background Art

[0002] In the field of underwater communication and positioning technology, sound waves are currently the only information carrier that can achieve long-distance propagation in seawater. Since the underwater acoustic channel is a random multipath channel, it has the characteristics of time-varying, frequency-varying, and space-varying, and has the characteristics of narrow bandwidth and high noise. These characteristics bring great challenges to underwater communication and positioning, especially in waveform design.

[0003] Traditional underwater acoustic communication systems pursue high speed and high reliability, while underwater positioning systems focus on measurement accuracy. However, since communication and positioning are two different business requirements, their waveform designs often need to be carried out separately, which leads to resource waste and system performance limitations. Therefore, the fusion waveform design of communication and positioning has become a research hotspot.

[0004] Therefore, it is necessary to provide an integrated waveform design method that takes into account both communication and positioning performance. Summary of the invention

[0005] The present invention proposes a waveform design method for underwater communication and positioning based on a sparse vector coding matrix, which aims to improve the joint performance of the underwater communication and positioning integrated system in a changeable marine environment, and at the same time obtain performance gains in underwater acoustic digital communication and underwater target positioning.

[0006] Specifically, at the transmitting end, the present invention first performs sparse processing on the binary data, corresponds it to a high-dimensional sparse vector, and then uses a coding matrix to convert it into a transmittable reduced-dimensional modulation symbol, which corresponds to the QAM modulation symbol. Through discrete Fourier transform, the required communication and positioning integrated waveform is obtained. This waveform has ultra-reliability and good autocorrelation performance, and can be used in both communication and positioning. At the receiving end, according to the communication and positioning requirements, an underwater acoustic communication receiver performs demodulation and decoding processing and an underwater acoustic positioning receiver performs ranging and direction finding processing.

[0007] The present invention provides a method for designing an underwater communication and positioning integrated waveform, comprising:

[0008] S1, sparse vector mapping: convert the serial binary data obtained by source coding into a high-dimensional sparse vector, and represent the information by the different positions of the valued elements in the sparse vector. The length of the vector is large enough so that the number of its position combinations is greater than the number of possible values ​​of the binary data;

[0009] S2, coding matrix dimensionality reduction: using the designed coding matrix, multiplying the high-dimensional sparse vector to obtain the reduced-dimensional transmission modulation symbols, which correspond to QAM modulation symbols, and their order depends on the number of valued elements in the sparse vector;

[0010] S3, pilot generation and insertion: The preset training sequence is also subjected to the above processes S1 and S2 to obtain modulation symbols, and is inserted as a comb or block pilot. To ensure good autocorrelation of the waveform, the training sequence needs to be determined in the bit domain and cannot be directly inserted into the QAM modulation symbol;

[0011] S4. IFFT waveform generation: Through inverse discrete Fourier transform, the modulation symbols are converted into orthogonal frequency division multiplexing modulation waveforms, which can be used for underwater acoustic communication and underwater target positioning respectively.

[0012] Preferably, at the receiving end, according to communication and positioning requirements, an underwater acoustic communication receiver performs demodulation and decoding processing and an underwater acoustic positioning receiver performs ranging and direction finding processing respectively.

[0013] Preferably, at the communication level, due to the ultra-reliable and low-latency characteristics of sparse vector coding, the underwater acoustic communication system constructed based on this waveform has a significant reliability gain compared to the conventional underwater acoustic communication system.

[0014] Preferably, at the positioning level, the waveform has good autocorrelation performance, and the hydroacoustic positioning system constructed based on the waveform has higher measurement accuracy than the conventional hydroacoustic positioning system.

[0015] The present invention proposes an underwater acoustic communication system based on an underwater communication and positioning integrated waveform design method, and the system uses the underwater communication and positioning integrated waveform generated by the method to perform communication and positioning.

[0016] Preferably, the system uses the underwater communication and positioning integrated waveform generated by the method to measure the position of the target

[0017] Compared with the related art, the underwater communication and positioning integrated waveform design method provided by the present invention has the following beneficial effects:

[0018] The present invention uses sparse vector coding technology based on compressed sensing theory to complete waveform and pilot design, which has significant advantages over traditional waveforms;

[0019] At the communication level, due to the ultra-reliable and low-latency characteristics of sparse vector coding, the underwater acoustic communication system built based on this waveform has a significant reliability gain compared to conventional underwater acoustic communication systems;

[0020] At the positioning level, this waveform has good autocorrelation performance, and the hydroacoustic positioning system built based on this waveform has higher measurement accuracy than conventional hydroacoustic positioning systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a method for designing an underwater communication and positioning integrated waveform provided by the present invention;

[0022] Figure 2 A time domain diagram of an underwater communication and positioning integrated waveform provided by the present invention;

[0023] Figure 3 It is the corresponding modulation symbol constellation mapping diagram in the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0025] The present invention provides a method for designing an underwater communication and positioning integrated waveform, the process of which is shown in the attached figure. Figure 1 As shown in the figure, this method optimizes communication and positioning performance through fusion design. The specific implementation steps are as follows:

[0026] (1) Communication signal conversion: First, the source-coded data is imported. These data are serial binary data obtained after the original information is processed by source coding. Through a specific conversion algorithm, these binary data are converted into high-dimensional sparse signals. There is a one-to-one mapping relationship between the high-dimensional sparse signal and the communication signal, ensuring the integrity and accuracy of the information.

[0027] (2) Transmission signal generation: The high-dimensional sparse signal is converted into low-dimensional transmission symbols using a sparse vector coding matrix. This step involves the process of reducing the dimension of the coding matrix, where the coding matrix is ​​multiplied by the high-dimensional sparse vector to obtain the reduced-dimensional transmission modulation symbols. These modulation symbols correspond to QAM (Quadrature Amplitude Modulation) modulation symbols, and their order depends on the number of valued elements in the sparse vector.

[0028] (3) Pilot sequence insertion: The pilot sequence that is adapted to the sparse vector coding is inserted to ensure the low peak sidelobe ratio characteristics of the signal. The pilot sequence is inserted to accurately demodulate and locate the signal at the receiving end. The pilot sequence is obtained by the same sparse vector mapping and coding matrix dimension reduction process as the communication signal to obtain the modulation symbol, and is inserted into the waveform as a comb or block pilot. In order to ensure good autocorrelation of the waveform, the training sequence needs to be determined in the bit domain and cannot be directly inserted into the QAM modulation symbol.

[0029] (4) Integrated waveform generation: The low-dimensional transmission symbols are subjected to an inverse discrete Fourier transform (IFFT) to generate an integrated waveform. This waveform is equivalent to the orthogonal frequency division multiplexing (OFDM) modulation waveform and can be used for underwater acoustic communication and underwater target positioning respectively. The inverse discrete Fourier transform is the process of converting frequency domain signals into time domain signals. The resulting waveform is suitable for both communication and positioning.

[0030] (5) Integrated function realization: The integrated function is realized at the receiving end. For communication reception, demodulation and decoding are performed at the receiving end to restore the original data. For positioning reception, the positioning algorithm is used at the receiving end to calculate the position of the target. This step involves the coordinated work of the underwater acoustic communication receiver and the underwater acoustic positioning receiver to handle the communication and positioning requirements respectively.

[0031] As attached Figure 2 The generated underwater communication and positioning integrated waveform time domain diagram is shown, showing the distribution of the integrated waveform in time, as shown in the attached figure. Figure 3 The corresponding modulation symbol constellation diagram (4QAM) is shown, showing the distribution of symbols under 4QAM modulation, which helps to understand the modulation characteristics of the waveform and the transmission method of the signal.

[0032] To sum up the above description, the present invention not only improves the joint performance of the underwater communication and positioning integrated system in a changeable marine environment, but also obtains performance gains in underwater acoustic digital communication and underwater target positioning, thereby improving the reliability of underwater communication and the accuracy of positioning.

[0033] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for designing an underwater communication and positioning integrated waveform, characterized in that: include: S1, sparse vector mapping; S2, encoding matrix dimensionality reduction; S3, pilot generation insertion; S4, IFFT waveform generation.

2. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: The sparse vector mapping specifically includes the following steps: converting serial binary data obtained through source coding into a high-dimensional sparse vector, representing information by the different positions of valued elements in the sparse vector, and the length of the vector is large enough so that the number of its position combinations is greater than the number of possible values ​​of the binary data.

3. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: The coding matrix dimensionality reduction specifically includes the following steps: using the designed coding matrix to multiply with the high-dimensional sparse vector to obtain reduced-dimensional transmission modulation symbols, which correspond to QAM modulation symbols, and their order depends on the number of valued elements in the sparse vector.

4. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: The pilot generation and insertion specifically includes the following steps: the preset training sequence is also subjected to the above processes S1 and S2 to obtain a modulation symbol, and is inserted as a comb or block pilot. To ensure good autocorrelation of the waveform, the training sequence needs to be determined in the bit domain and cannot be directly inserted into the QAM modulation symbol.

5. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: The generation of the IFFT waveform specifically includes the following steps: by inverse discrete Fourier transform, the modulation symbols are converted into an orthogonal frequency division multiplexing modulation waveform, which can be used for underwater acoustic communication and underwater target positioning respectively.

6. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: At the receiving end, in order to meet the communication and positioning needs, there are underwater acoustic communication receivers to perform demodulation and decoding processing and underwater acoustic positioning receivers to perform ranging and direction finding processing respectively.

7. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: At the communication level, due to the ultra-reliable and low-latency characteristics of sparse vector coding, the underwater acoustic communication system built based on this waveform has a significant reliability gain compared to conventional underwater acoustic communication systems.

8. The underwater communication and positioning integrated waveform design method according to claim 1, characterized in that: At the positioning level, this waveform has good autocorrelation performance, and the hydroacoustic positioning system built based on this waveform has higher measurement accuracy than conventional hydroacoustic positioning systems.

9. An underwater acoustic communication system based on the underwater communication and positioning integrated waveform design method according to any one of claims 1 to 8, characterized in that: The system uses the underwater communication and positioning integrated waveform generated by the method to perform communication and positioning.

10. The hydroacoustic positioning system according to claim 9, characterized in that: The system uses the underwater communication and positioning integrated waveform generated by the method to measure the position of the target.

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