Efficient beam separation method and apparatus in unlicensed multi-beam satellite communication system

Abstract

The application provides a high-efficiency beam separation method and device in an unlicensed multi-beam satellite communication system, and is applied to the technical field of satellite communication, wherein the method comprises the following steps: performing first-stage frequency conversion filtering and downsampling on a target number of subbands to obtain a coarse-grained signal; performing second-stage frequency conversion on the coarse-grained signal based on the target number of subbands to obtain two side frequency points of the subband; performing second-stage filtering and downsampling on the two side frequency points to obtain a fine-grained signal; selecting a corresponding signal branch from the fine-grained signal based on a center frequency point of each beam in a plurality of beams to perform third-stage frequency conversion filtering and downsampling to obtain a target beam signal; and performing fourth-stage matching filtering on the target beam signals corresponding to the plurality of beams respectively through a preset matching filter to obtain parallel separation signals corresponding to the plurality of beams respectively. Through the application, the calculation complexity can be reduced through step-by-step frequency conversion, and the beam extraction effect can be optimized in combination with a multi-stage filter group.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and in particular to an efficient beam splitting method and apparatus for an unlicensed multi-beam satellite communication system. Background Technology

[0002] In high-orbit satellite multi-beam systems, the gateway station receiver simultaneously receives signals from multiple beams across the entire communication bandwidth, typically covering hundreds of megahertz. With the development of satellite communication technology, high-orbit satellites employ multi-beam technology to improve communication capacity and spectrum utilization, enabling a single satellite to cover a wider geographical area and enhancing the system's spectrum reuse capability.

[0003] Existing beam splitting techniques mainly include beamforming and blind source separation methods. Beamforming relies on antenna arrays and adaptive weighting to enhance signals in specific directions, but this method typically requires complex array calibration and high computational costs, making it difficult to implement in resource-constrained systems. Blind source separation techniques are based on statistical signal processing methods, such as independent component analysis or minimum mean square error, but their computational complexity is high, and their separation accuracy is limited in highly dynamic satellite environments.

[0004] It is evident that beam splitting methods in related technologies suffer from high computational complexity. Summary of the Invention

[0005] This invention provides an efficient beam splitting method and apparatus for an unlicensed multi-beam satellite communication system, which addresses the high computational complexity of existing beam splitting methods by implementing step-by-step frequency conversion to reduce computational complexity, while simultaneously optimizing beam extraction performance by combining multi-stage filter banks.

[0006] This invention provides an efficient beam splitting method in an unlicensed multi-beam satellite communication system, comprising the following steps: Preprocessing and down-converting the full bandwidth signals of multiple received beams to obtain a baseband signal, wherein the full bandwidth signal includes: beam signals and interference signals; dividing the baseband signal into a target number of sub-bands based on a predetermined target number of fixed center frequencies; performing a first-stage frequency conversion filtering and downsampling on the target number of sub-bands to obtain a coarse-grained signal; performing a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the two side frequencies of the sub-bands; and performing a second-stage filtering and downsampling on the two side frequencies to obtain a fine-grained signal; selecting a corresponding signal path from the fine-grained signal based on the center frequency of each beam in the multiple beams for a third-stage frequency conversion filtering and downsampling to obtain the target beam signals corresponding to each of the multiple beams; and performing a fourth-stage matched filtering on the target beam signals corresponding to each of the multiple beams using a predetermined matched filter to obtain the parallel split signals corresponding to each of the multiple beams.

[0007] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system, wherein dividing the baseband signal into the target number of sub-bands based on a preset target number of fixed center frequencies includes: dividing the baseband signal into the target number of sub-bands based on a preset number of fixed center frequencies. The baseband signal is divided into several fixed center frequencies. There are several sub-bands, wherein the set of center frequency points of the sub-bands is:

[0008] ;

[0009] in, Represents the set of center frequency points of the sub-band. Indicates the first The individual has a center frequency point. This represents the total bandwidth of the baseband signal. This indicates the total number of sub-bands. This indicates a sub-band index.

[0010] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system, wherein performing a first-stage frequency conversion filtering and downsampling on the target number of subbands to obtain a coarse-grained signal includes: [The method involves]... Each sub-band is converted to its center frequency in parallel, and a coarse-grained signal is extracted while being downsampled using a first filter.

[0011] ;

[0012] in, Represents a set of coarse-grained signals. Indicates the first Each sub-band corresponds to a coarse-grained signal. This indicates that the full bandwidth signal will be used. Frequency conversion to the first Individual band center frequency point , This indicates the total number of sub-bands. Indicates a sub-band index. This represents the first filter, where the first filter represents... The Kaiser window multiphase filter has an order of 31.

[0013] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system includes: performing a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and performing a second-stage filtering and downsampling on the frequency points on both sides to obtain a fine-grained signal. The method comprises: converting the coarse-grained signal to the frequency points on both sides of the sub-band, and refining the frequency points on both sides using a second filter to obtain a fine-grained signal.

[0014] ;

[0015] in, Represents a set of fine-grained signals. Indicates the first Each sub-band corresponds to a fine-grained signal. This represents the set of coarse-grained signals. Frequency conversion to both sides of the sub-band , This represents the second filter, which represents... The Kaiser window filter has an order of 53.

[0016] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system, based on the center frequency of each of the multiple beams, selects corresponding signal splitters from the fine-grained signal for third-stage frequency conversion filtering and downsampling to obtain target beam signals corresponding to the multiple beams respectively. The method includes: determining the correction frequency point corresponding to the center frequency of each of the multiple beams in the fine-grained signal, and the signal splitter for each of the multiple beams in the fine-grained signal; frequency-converting the signal splitters to zero frequency based on the correction frequency point, and extracting the target beam signals corresponding to the multiple beams respectively through a third filter.

[0017] ;

[0018] Represents the target beam signal set. Indicates the first The target beam signal corresponding to each beam. Indicates the first The center frequency of each beam The corresponding signal branch, Indicates based on the correction frequency point Split the signal Frequency conversion to zero frequency, This indicates the total number of beams. Indicates beam index, This refers to the third filter, which is... The Kaiser window filter has an order of 72.

[0019] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system is provided. The method involves performing a fourth-level matched filtering on the target beam signals corresponding to the multiple beams through a preset matched filter to obtain parallel splitting signals corresponding to the multiple beams. The method includes performing time-frequency feature conjugate matching on the target beam signals corresponding to the multiple beams through a preset matched filter to obtain parallel splitting signals corresponding to the multiple beams.

[0020] This invention also provides an efficient beam splitting device for an unlicensed multi-beam satellite communication system, comprising the following modules: a preprocessing module for preprocessing and down-converting the full bandwidth signals of multiple received beams to obtain a baseband signal, wherein the full bandwidth signal includes beam signals and interference signals; a division module for dividing the baseband signal into a target number of sub-bands based on a preset target number of fixed center frequency points; a first frequency conversion filtering module for performing a first-stage frequency conversion filtering and downsampling on the target number of sub-bands to obtain a coarse-grained signal; and a second frequency conversion filtering module for dividing the target number of sub-bands into a coarse-grained signal based on the target number of sub-bands. The coarse-grained signal is subjected to a second-stage frequency conversion to obtain the frequency points on both sides of the sub-band; and the frequency points on both sides are subjected to a second-stage filtering and downsampling to obtain a fine-grained signal; a third frequency conversion filtering module is used to select the corresponding signal branch from the fine-grained signal based on the center frequency point of each of the multiple beams and perform a third-stage frequency conversion filtering and downsampling to obtain the target beam signals corresponding to the multiple beams respectively; a fourth matched filtering module is used to perform a fourth-stage matched filtering on the target beam signals corresponding to the multiple beams respectively through a preset matched filter to obtain the parallel separated signals corresponding to the multiple beams respectively.

[0021] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement an efficient beam splitting method in any of the above-described unlicensed multi-beam satellite communication systems.

[0022] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an efficient beam splitting method in any of the above-described unlicensed multi-beam satellite communication systems.

[0023] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements an efficient beam splitting method in any of the above-described unlicensed multi-beam satellite communication systems.

[0024] This invention provides an efficient beam splitting method and apparatus for unlicensed multi-beam satellite communication systems. After preprocessing and down-conversion to extract the baseband signal, the first-stage frequency conversion (based on a fixed center frequency) combined with filtering and downsampling divides the full-bandwidth signal into coarse-grained sub-bands, reducing the amount of data processed. The second-stage frequency conversion performs secondary frequency shifting and filtering on the frequency points on both sides of the sub-band, refining the segmentation of adjacent frequency point signals and eliminating inter-band interference. The third-stage frequency conversion dynamically selects the target sub-band based on the beam center frequency and accurately aligns the spectrum to suppress adjacent-channel interference. Finally, the fourth-stage matched filter performs time-frequency domain optimization matching on the target sub-band signal to enhance the target beam signal energy, ultimately achieving efficient parallel beam splitting of multiple beams under unlicensed spectrum, balancing low complexity and high precision. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced one by one below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the efficient beam splitting method in an unlicensed multi-beam satellite communication system provided by the present invention.

[0027] Figure 2 This is a flowchart of the beam splitting system for an unlicensed satellite covert communication system based on a multi-level filter bank, provided by the present invention.

[0028] Figure 3 This is a block diagram of a beam splitting system for an unlicensed satellite covert communication system based on a multi-level filter bank, provided by the present invention.

[0029] Figure 4 This is a schematic diagram of an efficient beam splitter in an unlicensed multibeam satellite communication system provided by the present invention.

[0030] Figure 5 This is a schematic diagram of the physical structure of the electronic device provided by the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] In high-orbit satellite multi-beam systems, the gateway station receiver simultaneously receives signals from multiple beams across the entire communication bandwidth, typically covering hundreds of megahertz. With the development of satellite communication technology, high-orbit satellites employ multi-beam technology to improve communication capacity and spectrum utilization, enabling a single satellite to cover a wider geographical area and enhancing the system's spectrum reuse capability. However, the characteristics of multi-beam communication systems mean that the gateway station needs to process a large number of mixed signals from different beams during reception; effectively separating the target beam becomes a key challenge.

[0033] Existing beam splitting techniques mainly include beamforming, blind source separation, and traditional bandpass filtering methods. Beamforming relies on antenna arrays and adaptive weighting to enhance signals in specific directions, but this method typically requires complex array calibration and high computational costs, making it difficult to implement in resource-constrained systems. Blind source separation techniques are based on statistical signal processing methods, such as independent component analysis or minimum mean square error, but their computational complexity is high, and their separation accuracy is limited in highly dynamic satellite environments.

[0034] Bandpass filtering is a common beam splitting method that extracts the spectral components of the target beam by applying a series of filters at the receiver. However, traditional single-stage filtering methods are difficult to adapt to complex multi-beam environments, easily leading to signal leakage and aliasing problems. Furthermore, for broadband receiving systems, single-bandwidth filtering struggles to balance computational efficiency and signal extraction accuracy; therefore, more sophisticated hierarchical filtering strategies are needed.

[0035] To address the aforementioned problems, this invention proposes a beam separation algorithm based on three-stage frequency conversion calculation and four-stage filtering. This method reduces computational complexity through step-by-step frequency conversion and optimizes beam extraction performance by combining multi-stage filter banks, achieving efficient separation of the target beam signal while ensuring real-time performance.

[0036] Specifically, this invention relates to an efficient beam splitting method for unlicensed multi-beam satellite communication systems, particularly suitable for multi-beam signal separation and processing in covert communication scenarios using unlicensed frequency bands. Through a multi-stage filter bank structure, efficient separation of multiple beams in broadband signals is achieved, improving signal processing efficiency and concealment.

[0037] Optionally, the efficient beam splitting method in the unlicensed multi-beam satellite communication system of this application embodiment can be executed by a server, by a terminal device, or by both a server and a terminal device. For example, the efficient beam splitting method in the unlicensed multi-beam satellite communication system of this embodiment can be executed by a signal receiving end.

[0038] Figure 1 This is a flowchart illustrating the efficient beam splitting method in an unlicensed multi-beam satellite communication system provided by the present invention, as shown below. Figure 1 As shown, the method includes the following steps.

[0039] Step 101: Preprocess and downconvert the full bandwidth signals of the received multiple beams to obtain the baseband signal.

[0040] The full-bandwidth signal includes both beam signals and interference signals.

[0041] In this embodiment of the invention, the full bandwidth signal from a high-orbit satellite is received and preprocessed with low-noise amplification, down-conversion, analog-to-digital conversion, etc., to achieve a full bandwidth of [missing information]. Include The complete signal of each beam Down-convert to baseband, where, Indicates a full-bandwidth signal. Indicates the first One beam signal, Indicates noise and interference signals. This indicates the total number of beams.

[0042] For example, after receiving the full-bandwidth signal from a high-orbit satellite, the signal strength is first enhanced by a low-noise amplifier, then the high-frequency signal (i.e., the full-bandwidth signal) is shifted to the baseband (low-frequency band) by a downconverter, and finally, analog-to-digital conversion is performed to generate a digital baseband signal. This process requires filtering out out-of-band interference to ensure the purity of the baseband signal.

[0043] Step 102: Divide the baseband signal into a target number of subbands based on a preset target number of fixed center frequency points.

[0044] In this embodiment of the invention, the baseband signal is divided into multiple equal-width sub-bands (e.g., four sub-bands) according to a preset fixed center frequency (e.g., uniformly distributed), with each sub-band covering a portion of the total bandwidth. Frequency domain segmentation is achieved through a polyphase filter bank, avoiding spectral aliasing.

[0045] For example, based on the selected The baseband signal is divided into three parts by a fixed center frequency point. Each bandwidth is Sub-band.

[0046] Step 103: Perform first-stage frequency conversion filtering and downsampling on the target number of subbands to obtain a coarse-grained signal.

[0047] In this embodiment of the invention, each subband is frequency-converted and moved to the vicinity of the baseband (zero frequency). Then, the target frequency band is retained by a Kaiser window multiphase filter, and the sampling rate is reduced to reduce the amount of data. The output is a coarse-grained (subband) signal with a wide bandwidth (e.g., 25MHz).

[0048] Step 104: Perform a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and perform a second-stage filtering and downsampling on the frequency points on both sides to obtain the fine-grained signal.

[0049] In this embodiment of the invention, based on the coarse-grained signal, the frequency points on both sides of the sub-band are dynamically selected ( After the second frequency conversion, a finer sub-band is extracted through a filter with a narrower bandwidth, and further downsampled to output a segmented fine-grained signal.

[0050] Step 105: Based on the center frequency of each of the multiple beams, select the corresponding signal branch from the fine-grained signal and perform third-level frequency conversion filtering and downsampling to obtain the target beam signal corresponding to each of the multiple beams.

[0051] In this embodiment of the invention, based on the center frequency of each beam, a matching sub-band is selected from the second-level segmentation signal (fine-grained signal), and it is moved back to the baseband (0 frequency) by frequency conversion. The target beam signal is then accurately extracted using a narrowband filter (e.g., 5MHz bandwidth) to complete downsampling.

[0052] Step 106: Using a preset matched filter, perform fourth-level matched filtering on the target beam signals corresponding to multiple beams to obtain parallel separated signals corresponding to multiple beams.

[0053] In this embodiment of the invention, a preset matched filter (such as a raised cosine filter) is loaded for each target beam signal. The signal-to-noise ratio of the target signal is enhanced by time-domain waveform matching, residual interference is suppressed, and finally multiple independent parallel beam signals are output, which can be directly used for demodulation or transmission.

[0054] Through the steps described in this embodiment of the invention, after preprocessing and downconversion to extract the baseband signal, the first-stage frequency conversion (based on a fixed center frequency) combined with filtering and downsampling divides the full bandwidth signal into coarse-grained sub-bands, reducing the amount of data processed by the signal; the second-stage frequency conversion performs secondary frequency shifting and filtering on the frequency points on both sides of the sub-band to refine the segmentation of adjacent frequency point signals and eliminate inter-band interference; the third-stage frequency conversion dynamically selects the target sub-band according to the beam center frequency and accurately aligns the spectrum to suppress adjacent channel interference; finally, the fourth-stage matched filter performs time-frequency domain optimization matching on the target sub-band signal to enhance the energy of the target beam signal, ultimately achieving efficient parallel separation of multiple beams under unlicensed spectrum, balancing low complexity and high precision.

[0055] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system, wherein dividing the baseband signal into the target number of subbands based on a preset target number of fixed center frequency points includes:

[0056] According to the preset The baseband signal is divided into several fixed center frequencies. There are several sub-bands, wherein the set of center frequency points of the sub-bands is:

[0057] ;

[0058] in, Represents the set of center frequency points of the sub-band. Indicates the first The individual has a center frequency point. This represents the total bandwidth of the baseband signal. This indicates the total number of sub-bands. This indicates a sub-band index.

[0059] In this embodiment of the invention, the formula is expressed as an expression. Achieve symmetrical distribution of sub-band center frequencies. Divide the total bandwidth of the baseband signal into... There are 16 equal-width sub-bands, each with a width of 100 mm. .

[0060] Through the embodiments of this invention, the total bandwidth of the baseband signal is uniformly divided into K sub-bands by mathematical design. The center frequency points of each sub-band are symmetrically distributed on both sides of the baseband, which can meet the requirements of uniform division and no overlap. By adjusting... The value control signal is divided into granularities to adapt to different scenario requirements.

[0061] According to the present invention, an efficient beam splitting method for an unlicensed multibeam satellite communication system is provided, which divides the beams into three parts. Each sub-band is converted to its center frequency in parallel, and a coarse-grained signal is extracted while being downsampled using a first filter.

[0062] ;

[0063] in, Represents a set of coarse-grained signals. Indicates the first Each sub-band corresponds to a coarse-grained signal. This indicates that the full bandwidth signal will be used. Frequency conversion to the first Individual band center frequency point , This indicates the total number of sub-bands. Indicates a sub-band index. This represents the first filter, where the first filter represents... The Kaiser window multiphase filter has an order of 31.

[0064] In this embodiment of the invention, the full bandwidth signal The frequency band is divided into Each narrowband sub-band has a center frequency point determined by... Sure.

[0065] For each sub-band Full bandwidth signal Multiply Shift the spectrum to the center frequency of the sub-band Therefore, the original baseband signal (near frequency 0) is shifted to a frequency domain position. This generates a narrowband (signal) centered on the center frequency of that subband. Here, all... Each sub-band operates independently through frequency conversion, forming a parallel processing channel.

[0066] Among them, the complex index It is a fundamental tool in signal processing; multiplying by a complex exponent in the time domain is equivalent to shifting the signal's spectrum to the left in the frequency domain. (Negative frequency direction). The complex exponent is composed of cosine (real part) and sine (imaginary part), and can fully represent the amplitude and phase information of the signal.

[0067] First filter express The Kaiser window multiphase filter, with an order of 31, has a stopband attenuation ≥50dB (used to suppress interference between adjacent subbands). It performs downsampling on the signal during filtering. It can be The width is consistent with the sub-band width (e.g., total bandwidth 100MHz). When =4, =25MHz).

[0068] Through this embodiment of the invention, by using parallel frequency conversion, filtering, and downsampling, the broadband baseband signal is efficiently divided into multiple narrowband sub-bands, and the bandwidth of each sub-band signal is reduced to [missing information]. The amount of data was reduced to .

[0069] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system includes: performing a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and performing a second-stage filtering and downsampling on the frequency points on both sides to obtain a fine-grained signal, comprising:

[0070] The coarse-grained signal is frequency-converted to the frequency points on both sides of the sub-band, and then the frequency points on both sides are refined and segmented through a second filter to obtain a fine-grained signal:

[0071] ;

[0072] in, Represents a set of fine-grained signals. Indicates the first Each sub-band corresponds to a fine-grained signal. This represents the set of coarse-grained signals. Frequency conversion to both sides of the sub-band , This represents the second filter, which represents... The Kaiser window filter has an order of 53.

[0073] Among them, the complex index It is a fundamental tool in signal processing; multiplying by a complex exponent in the time domain is equivalent to shifting the signal's spectrum to the left in the frequency domain. (Negative frequency direction). The complex exponent is composed of cosine (real part) and sine (imaginary part), and can fully represent the amplitude and phase information of the signal.

[0074] In this embodiment of the invention, the coarse-grained signal after the first-stage filtering is... Shift the frequency again to both sides. and through The bandwidth filter is refined and segmented.

[0075] For coarse-grained signals Perform two frequency conversion operations, multiply by respectively and This generates frequency signals on the left and right sides. Here, each coarse-grained signal is processed in parallel, and each coarse-grained signal (sub-band) is split into two fine-grained signals (sub-bands).

[0076] In this embodiment of the invention, the second filter represents... Kaiser window filter, It can be It has an order of 53 and a stopband attenuation of ≥50dB, which is used to suppress interference between adjacent fine-grained subbands and ensure signal purity.

[0077] In this embodiment of the invention, the second-level processing further divides the coarse-grained subband into a narrower fine-grained signal through dynamic frequency conversion and fine filtering.

[0078] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system is provided, which, based on the center frequency of each of the multiple beams, selects the corresponding signal branch from the fine-grained signal and performs a third-stage frequency conversion filtering and downsampling to obtain the target beam signals corresponding to the multiple beams respectively, including:

[0079] Determine the correction frequency point corresponding to the center frequency point of each of the plurality of beams in the fine-grained signal, and the signal splitting of each of the plurality of beams in the fine-grained signal;

[0080] Based on the correction frequency point, the signal is split and frequency-converted to zero frequency, and the target beam signals corresponding to the multiple beams are extracted through a third filter:

[0081] ;

[0082] Represents the target beam signal set. Indicates the first The target beam signal corresponding to each beam. Indicates the first The signal branching corresponding to the center frequency of each beam Indicates based on the correction frequency point Split the signal Frequency conversion to zero frequency, This indicates the total number of beams. Indicates beam index, This refers to the third filter, which is... The Kaiser window filter has an order of 72.

[0083] Among them, the complex index It is a fundamental tool in signal processing; multiplying by a complex exponent in the time domain is equivalent to shifting the signal's spectrum to the left in the frequency domain. (Negative frequency direction). The complex exponent is composed of cosine (real part) and sine (imaginary part), and can fully represent the amplitude and phase information of the signal.

[0084] In this embodiment of the invention, the calculated value (correction value) of each beam center frequency point after multiple frequency conversions is used. ,exist Select the corresponding signal branch Perform a third frequency conversion to baseband, through The filter extracts the target beam.

[0085] This represents the compensation frequency offset (i.e., the correction frequency point) used to shift fine-grained signals back to baseband (zero frequency).

[0086] Here, Multiply This cancels out the accumulated frequency offset of the first two stages, enabling signal splitting. The baseband is regressed, which facilitates subsequent filtering to extract the target bandwidth.

[0087] Third filter for A Kaiser window filter, order 72, with a stopband attenuation ≥50dB. The target beam (actual) bandwidth, such as a typical satellite beam of 5MHz.

[0088] Through this embodiment of the invention, the cumulative frequency offset of the first two stages is canceled by reverse frequency conversion, ensuring the signal returns to the baseband. Dynamic matching of the original frequency point of the target beam with fine-grained sub-bands avoids omissions or aliasing. A high-order filter (72nd order) suppresses adjacent beams and noise, improving the signal-to-noise ratio.

[0089] According to the present invention, an efficient beam splitting method in an unlicensed multi-beam satellite communication system is provided. This method uses a preset matched filter to perform a fourth-level matched filter on the target beam signals corresponding to multiple beams, obtaining parallel splitting signals corresponding to the multiple beams, including:

[0090] By using a preset matched filter, time-frequency feature conjugate matching is performed on the target beam signals corresponding to multiple beams to obtain parallel separated signals corresponding to multiple beams.

[0091] In this embodiment of the invention, a matched filter is designed. To enhance the target beam signal, suppress interference, and maximize the output signal-to-noise ratio, the output signal is:

[0092] ;

[0093] in, The output consists of parallel separated signals corresponding to the multiple beams. Represents the target beam signal set. This represents a matched filter.

[0094] Through the above embodiments of the present invention, addressing the problems of low accuracy, weak anti-interference capability, and slow processing speed of existing beam separation technologies when processing complex signals at the gateway station receiver in a high-orbit satellite multi-beam system, the present invention provides a beam separation method for an unlicensed satellite covert communication system based on a four-stage filter bank and a three-stage frequency conversion calculation. This method, through dynamic frequency point selection, adaptive filtering, and matched filtering optimization, can efficiently separate multiple beam signals from the complete signal bandwidth, improve the covertness and anti-interference capability of the communication system, and achieve high-precision beam separation while reducing the computational load.

[0095] The following describes an example of the efficient beam splitting method in an unlicensed multi-beam satellite communication system provided by the present invention in a practical application.

[0096] This invention employs a three-stage frequency conversion combined with a four-stage filtering network to form a complete frequency conversion filtering network, progressively downsampling and achieving efficient beam separation. Let the received signal (the full bandwidth signal of the received multiple beams) be: ,in, Indicates the first One beam signal, For noise and interference signals, This refers to the total number of multiple beams. In the first-stage frequency conversion filtering operation, based on... A fixed center frequency point is used to convert the received signal to the target sub-band, and then... A bandwidth filter extracts coarse-grained signals; a second-stage frequency conversion filter dynamically selects the center frequency point on both sides of the sub-band output of the second stage. The bandwidth filter refines the segmentation to obtain a fine-grained signal; the third-stage frequency conversion filter performs baseband frequency conversion at the sub-band center frequency point of the second-stage output based on the target beam position. Simultaneously, the filter, which also controls the bandwidth of the beam signal, separates the narrowband beam signal to obtain the target beam signal. Fourth-stage matched filtering: An optimal matched filter is designed to be conjugate-matched with the time-frequency characteristics of the target beam signal, suppressing noise and interference to obtain parallel separated signals corresponding to multiple beams.

[0097] The beam splitting method for unlicensed satellite covert communication systems proposed in this invention, based on a four-stage filter bank and three-stage frequency conversion calculation, includes the following steps:

[0098] Step 1: Receive broadband signals from high-orbit satellites and perform preprocessing such as low-noise amplification, down-conversion, and analog-to-digital conversion to achieve a total bandwidth of [missing information]. Include The complete signal of each beam (the full bandwidth signal of the multiple received beams) Down-convert to baseband.

[0099] Step Two: Based on the selected The signal is divided into several fixed center frequencies. Each bandwidth is The sub-bands, and the set of center frequencies of the sub-bands are:

[0100] ;

[0101] in, Represents the set of center frequency points of the sub-band. Indicates the first The individual has a center frequency point. This represents the total bandwidth of the baseband signal. This indicates the total number of sub-bands. This indicates a sub-band index.

[0102] right Each sub-band performs frequency conversion processing in parallel and through The filter extracts coarse-grained signals while downsampling, resulting in:

[0103] ;

[0104] in, Represents a set of coarse-grained signals. Indicates the first Each sub-band corresponds to a coarse-grained signal. This indicates that the full bandwidth signal will be used. Frequency conversion to the first Individual band center frequency point , This indicates the total number of sub-bands. Indicates a sub-band index. This represents the first filter, where the first filter represents... The Kaiser window multiphase filter has an order of 31 and a stopband attenuation of ≥50dB, and performs downsampling processing on the signal while filtering.

[0105] Step 3: Filter the signal after the first stage of filtering (i.e., the coarse-grained signal). Shift the frequency again to both sides. and through The bandwidth filter is further refined to obtain:

[0106] ;

[0107] in Represents a set of fine-grained signals. Indicates the first Each sub-band corresponds to a fine-grained signal. This represents the set of coarse-grained signals. Frequency conversion to both sides of the sub-band , This represents the second filter, which represents... The Kaiser window filter has an order of 53 and a stopband attenuation of ≥50dB.

[0108] After filtering Perform downsampling processing.

[0109] Step 4: Calculate the values ​​of each beam's center frequency after multiple frequency conversions. exist Select the corresponding signal branch Perform a third frequency conversion to baseband, through Filter extracts target beam:

[0110] ;

[0111] in, Represents the target beam signal set. Indicates the first The target beam signal corresponding to each beam. Indicates the first The signal branching corresponding to the center frequency of each beam Indicates based on the correction frequency point Split the signal Frequency conversion to zero frequency, This indicates the total number of beams. Indicates beam index, This refers to the third filter, which is... Kaiser window filter, filter The order is 72, and the stopband attenuation is ≥50dB.

[0112] Step 5: Design the matched filter To enhance the target beam signal, suppress interference, and maximize the output signal-to-noise ratio, the output signal is:

[0113] ;

[0114] in, The output consists of parallel separated signals corresponding to the multiple beams. Indicates the target beam signal. This represents a matched filter.

[0115] Step 6: Through the above steps, N signals with N beams output in parallel are obtained.

[0116] refer to Figure 2 , Figure 2This is a flowchart of a beam splitting system for an unlicensed satellite covert communication system based on a multi-level filter bank, provided by the present invention. Specifically, it includes the following steps:

[0117] The total bandwidth B of N beams total The MHz signal is input and down-converted to baseband.

[0118] K fixed center frequency points are selected at equal intervals, and the signal is divided into K sub-bands.

[0119] First-stage frequency conversion filtering: The K sub-bands are frequency converted in parallel and the coarse-grained signal is extracted while being downsampled by a B1MHz polyphase filter.

[0120] Second-stage frequency conversion filtering: The signal after the first-stage filtering is converted again to the frequency points on both sides of the sub-band, and then refined and segmented by a B2MHz bandwidth filter, followed by downsampling.

[0121] Third-stage frequency conversion filtering: Based on the calculated center frequency of each beam, the corresponding branch after the second-stage filtering is selected and frequency-converted to zero frequency, and the target beam is extracted through the B3MHz filter.

[0122] The N parallel signals are passed through a matched filter and then output.

[0123] refer to Figure 3 , Figure 3 This is a block diagram of a beam splitting system for an unlicensed satellite covert communication system based on a multi-stage filter bank, provided by the present invention. It includes: filter channel selection, direct digital synthesis (DDS), a B1MHz polyphase filter, a B2MHz filter, a B3MHz filter, matched filtering, a first-stage splitting into K paths, a second-stage splitting into 2K paths, and a third-stage splitting into N paths.

[0124] The following describes the efficient beam splitting device in the unlicensed multi-beam satellite communication system provided by the present invention. The efficient beam splitting device in the unlicensed multi-beam satellite communication system described below can be referred to in correspondence with the efficient beam splitting method in the unlicensed multi-beam satellite communication system described above.

[0125] refer to Figure 4 , Figure 4 This is a schematic diagram of an efficient beam splitter in an unlicensed multibeam satellite communication system provided by the present invention.

[0126] The preprocessing module 401 is used to preprocess and downconvert the full bandwidth signals of the received multiple beams to obtain a baseband signal, wherein the full bandwidth signal includes: beam signals and interference signals;

[0127] The partitioning module 402 is used to divide the baseband signal into the target number of subbands according to a preset target number of fixed center frequency points;

[0128] The first frequency conversion filtering module 403 is used to perform first-stage frequency conversion filtering and downsampling on the target number of sub-bands to obtain a coarse-grained signal.

[0129] The second frequency conversion filtering module 404 is used to perform a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and to perform a second-stage filtering and downsampling on the frequency points on both sides to obtain a fine-grained signal.

[0130] The third frequency conversion filtering module 405 is used to select the corresponding signal branch from the fine-grained signal based on the center frequency point of each of the multiple beams, and perform third-level frequency conversion filtering and downsampling to obtain the target beam signal corresponding to each of the multiple beams.

[0131] The fourth matched filtering module 406 is used to perform fourth-level matched filtering on the target beam signals corresponding to the multiple beams through a preset matched filter to obtain the parallel separated signals corresponding to the multiple beams.

[0132] Specifically, the high-efficiency beam splitting device in the unlicensed multi-beam satellite communication system provided by the present invention can realize all the method steps implemented in the embodiment of the high-efficiency beam splitting method in the unlicensed multi-beam satellite communication system, and can achieve the same technical effect. Here, the parts that are the same as those in the method embodiment and the beneficial effects will not be described in detail.

[0133] Figure 5 This is a schematic diagram of the physical structure of the electronic device provided by the present invention, such as... Figure 5As shown, the electronic device may include: a processor 510, a communications interface 520, a memory 530, and a communications bus 540, wherein the processor 510, the communications interface 520, and the memory 530 communicate with each other through the communications bus 540. The processor 510 can call logic instructions in the memory 530 to execute an efficient beam splitting method in an unlicensed multi-beam satellite communication system. This method includes: preprocessing and down-converting the full-bandwidth signals of multiple received beams to obtain baseband signals, wherein the full-bandwidth signals include beam signals and interference signals; dividing the baseband signals into a target number of sub-bands based on a preset target number of fixed center frequencies; performing a first-stage frequency conversion filtering and downsampling on the target number of sub-bands to obtain coarse-grained signals; performing a second-stage frequency conversion on the coarse-grained signals based on the target number of sub-bands to obtain the frequency points on both sides of the sub-bands; and performing a second-stage filtering and downsampling on the frequency points on both sides to obtain fine-grained signals; selecting corresponding signal paths from the fine-grained signals based on the center frequency of each beam in the multiple beams for a third-stage frequency conversion filtering and downsampling to obtain target beam signals corresponding to each of the multiple beams; and performing a fourth-stage matched filtering on the target beam signals corresponding to each of the multiple beams through a preset matched filter to obtain parallel split signals corresponding to each of the multiple beams.

[0134] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0135] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the efficient beam splitting method in the unlicensed multi-beam satellite communication system provided by the above methods. This method includes: preprocessing and down-converting the full bandwidth signals of multiple received beams to obtain a baseband signal, wherein the full bandwidth signal includes: beam signals and interference signals; dividing the baseband signal into a target number of sub-bands according to a preset target number of fixed center frequency points; and further processing the beam splitting method. The target number of subbands undergoes a first-stage frequency conversion filtering and downsampling to obtain a coarse-grained signal. Based on the target number of subbands, the coarse-grained signal undergoes a second-stage frequency conversion to obtain the frequency points on both sides of the subband. The frequency points on both sides undergo a second-stage filtering and downsampling to obtain a fine-grained signal. Based on the center frequency point of each beam in the multiple beams, the corresponding signal branch is selected from the fine-grained signal for a third-stage frequency conversion filtering and downsampling to obtain the target beam signals corresponding to the multiple beams. Through a preset matched filter, the target beam signals corresponding to the multiple beams undergo a fourth-stage matched filtering to obtain the parallel separated signals corresponding to the multiple beams.

[0136] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements an efficient beam splitting method in an unlicensed multi-beam satellite communication system provided by the methods described above. This method includes: preprocessing and down-converting the full-bandwidth signals of multiple received beams to obtain a baseband signal, wherein the full-bandwidth signal includes beam signals and interference signals; dividing the baseband signal into a target number of sub-bands according to a preset target number of fixed center frequency points; and performing a first-stage frequency conversion filtering on the target number of sub-bands. The signal is obtained by downsampling and filtering to obtain a coarse-grained signal. A second-stage frequency conversion is performed on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-bands. A second-stage filtering and downsampling is then performed on these frequency points to obtain a fine-grained signal. Based on the center frequency of each beam in the multiple beams, the corresponding signal path is selected from the fine-grained signal for a third-stage frequency conversion, filtering, and downsampling to obtain the target beam signals corresponding to each of the multiple beams. Finally, a fourth-stage matched filter is applied to the target beam signals corresponding to each of the multiple beams using a preset matched filter to obtain the parallel separated signals corresponding to each of the multiple beams.

[0137] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0138] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An efficient beam splitting method in an unlicensed multibeam satellite communication system, characterized in that, include: The received full-bandwidth signals from multiple beams are preprocessed and down-converted to obtain a baseband signal, wherein the full-bandwidth signal includes: beam signals and interference signals; The baseband signal is divided into the target number of subbands based on a predetermined target number of fixed center frequency points; The target number of subbands are subjected to first-stage frequency conversion filtering and downsampling to obtain a coarse-grained signal; The coarse-grained signal is subjected to a second-stage frequency conversion based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and the frequency points on both sides are subjected to a second-stage filtering and downsampling to obtain the fine-grained signal. Based on the center frequency of each of the multiple beams, the corresponding signal branch is selected from the fine-grained signal for third-level frequency conversion filtering and downsampling to obtain the target beam signal corresponding to each of the multiple beams; By using a preset matched filter, the target beam signals corresponding to the multiple beams are subjected to a fourth-level matched filter to obtain the parallel separation signals corresponding to the multiple beams.

2. The efficient beam splitting method in an unlicensed multi-beam satellite communication system according to claim 1, characterized in that, The step of dividing the baseband signal into the target number of sub-bands based on a preset target number of fixed center frequency points includes: According to the preset The baseband signal is divided into several fixed center frequencies. There are several sub-bands, wherein the set of center frequency points of the sub-bands is: ； in, Represents the set of center frequency points of the sub-band. Indicates the first The individual has a center frequency point. This represents the total bandwidth of the baseband signal. This indicates the total number of sub-bands. This indicates a sub-band index.

3. The efficient beam splitting method in an unlicensed multi-beam satellite communication system according to claim 2, characterized in that, The first-stage frequency conversion filtering and downsampling of the target number of sub-bands to obtain a coarse-grained signal includes: The Each sub-band is converted to its center frequency in parallel, and a coarse-grained signal is extracted while being downsampled using a first filter. ； in, Represents a set of coarse-grained signals. Indicates the first Each sub-band corresponds to a coarse-grained signal. This indicates that the full bandwidth signal will be used. Frequency conversion to the first Individual band center frequency point , This indicates the total number of sub-bands. Indicates a sub-band index. This represents the first filter, where the first filter represents... The Kaiser window multiphase filter has an order of 31.

4. The efficient beam splitting method in an unlicensed multi-beam satellite communication system according to claim 3, characterized in that, The coarse-grained signal is subjected to a second-stage frequency conversion based on the target number of sub-bands to obtain the frequency points on both sides of the sub-bands; A second-stage filtering and downsampling process is then performed on the two frequency points to obtain a fine-grained signal, including: The coarse-grained signal is frequency-converted to the frequency points on both sides of the sub-band, and then the frequency points on both sides are refined and segmented through a second filter to obtain a fine-grained signal: ； in, Represents a set of fine-grained signals. Indicates the first Each sub-band corresponds to a fine-grained signal. This represents the set of coarse-grained signals. Frequency conversion to both sides of the sub-band , This represents the second filter, which represents... The Kaiser window filter has an order of 53.

5. The efficient beam splitting method in an unlicensed multi-beam satellite communication system according to claim 4, characterized in that, Based on the center frequency of each of the plurality of beams, a corresponding signal branch is selected from the fine-grained signal for third-stage frequency conversion filtering and downsampling to obtain the target beam signals corresponding to the plurality of beams, including: Determine the correction frequency point corresponding to the center frequency point of each of the plurality of beams in the fine-grained signal, and the signal splitting of each of the plurality of beams in the fine-grained signal; Based on the correction frequency point, the signal is split and frequency-converted to zero frequency, and the target beam signals corresponding to the multiple beams are extracted through a third filter: ； Represents the target beam signal set. Indicates the first The target beam signal corresponding to each beam. Indicates the first The signal branching corresponding to the center frequency of each beam Indicates based on the correction frequency point Split the signal Frequency conversion to zero frequency, This indicates the total number of beams. Indicates beam index, This refers to the third filter, which is... The Kaiser window filter has an order of 72.

6. The efficient beam splitting method in an unlicensed multi-beam satellite communication system according to claim 1, characterized in that, The step of performing a fourth-level matched filter on the target beam signals corresponding to the multiple beams through a preset matched filter to obtain the parallel separation signals corresponding to the multiple beams includes: By using a preset matched filter, time-frequency feature conjugate matching is performed on the target beam signals corresponding to the multiple beams to obtain the parallel separated signals corresponding to the multiple beams.

7. A high-efficiency beam splitter in an unlicensed multi-beam satellite communication system, characterized in that, include: The preprocessing module is used to preprocess and downconvert the full-bandwidth signals of the received multiple beams to obtain a baseband signal, wherein the full-bandwidth signal includes: beam signals and interference signals; The partitioning module is used to divide the baseband signal into the target number of subbands according to a preset target number of fixed center frequency points; The first frequency conversion filtering module is used to perform first-stage frequency conversion filtering and downsampling on the target number of sub-bands to obtain a coarse-grained signal. The second frequency conversion filtering module is used to perform a second-stage frequency conversion on the coarse-grained signal based on the target number of sub-bands to obtain the frequency points on both sides of the sub-band; and to perform a second-stage filtering and downsampling on the frequency points on both sides to obtain a fine-grained signal. The third frequency conversion filtering module is used to select the corresponding signal branch from the fine-grained signal based on the center frequency point of each of the multiple beams, and perform third-level frequency conversion filtering and downsampling to obtain the target beam signal corresponding to each of the multiple beams. The fourth matched filtering module is used to perform fourth-level matched filtering on the target beam signals corresponding to the multiple beams through a preset matched filter, so as to obtain the parallel separated signals corresponding to the multiple beams.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the efficient beam splitting method in the unlicensed multi-beam satellite communication system as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the efficient beam splitting method in the unlicensed multi-beam satellite communication system as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the efficient beam splitting method in the unlicensed multi-beam satellite communication system as described in any one of claims 1 to 6.

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