Low-orbit satellite PAPR reduction method and device based on dynamic matching of beam patterns

Abstract

The present application provides a method and device for reducing PAPR of low-orbit satellites based on dynamic matching of beam patterns, the method comprising: obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern; constructing an optimal matching database of different beam patterns and the corresponding optimal reduction strategy according to a mapping relationship; adapting the most similar phased array antenna beam pattern to the optimal matching database to obtain the corresponding multi-user optimal selection coding sequence and multi-user optimal phase rotation combination; obtaining a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establishing a scaling function according to the scheduling period and elevation angle change; updating the control function and performing power adjustment according to the scaling function to obtain the final beamforming signal. The present application can ensure the quality of FBMC waveforms and effectively reduce the peak-to-average ratio under phased array agile beams.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a method and device for reducing PAPR of a low-orbit satellite based on dynamic matching of beam patterns. Background Art

[0002] The waveform design of low-orbit satellite Internet must fully consider the following factors that are significantly different from those on the ground: 1) Due to payload and energy limitations, satellites have strict requirements on the energy utilization efficiency of communication payloads. The design of communication waveforms requires that high reliability must be maintained when the communication payload is at the maximum upper limit. Since the onboard high power amplifier (HPA) causes serious nonlinear distortion to the signal in the oversaturation and saturation regions, the waveform design should fully consider suppressing the excessive power input of the HPA; 2) In the nonlinear distortion region of the HPA signal, especially multi-carrier systems such as FBMC and OFDM, it is easily affected by nonlinear distortion, and the output signal is seriously distorted; 3) The memory effect of broadband HPA is serious. The nonlinear distortion of traditional HPA can be suppressed and compensated by pre-distortion, but the low-orbit satellite channel is difficult to achieve real-time feedback processing due to large transmission delay and severe complex fading. Compared with OFDM, FBMC concentrates the energy of each subcarrier in the passband through a subband filter group, making the peak-to-average ratio (PAPR) more serious than OFDM. The above-mentioned problems applied to low-orbit satellite Internet will become more prominent.

[0003] The waveform suppression technology based on the selection sequence mapping in the prior art requires multiple attempts and iterations to traverse the optimal design due to the randomness of the sequence symbols, which is inefficient. In addition, the beam of the phased array low-orbit satellite will undergo sudden or continuous changes in the feeding direction due to the scheduling and movement of the wave position during the service cycle. The waveform suppression technology based on phase rotation has high computational complexity and low efficiency when the data rate is relatively high. In addition, the beam of the phased array low-orbit satellite will undergo sudden or continuous changes in the feeding direction due to the scheduling and movement of the wave position during the service cycle. Peak-to-average ratio suppression based on single carrier or constant envelope modulation requires the merging of multiple single carriers, which leads to a significant improvement after merging. The waveform suppression technology based on peak clipping will also change the power covering the ground due to the dynamic changes of the phased array low-orbit satellite. The fixed peak clipping threshold leads to energy waste of the onboard power amplifier or excessive peak clipping, resulting in severe signal distortion. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a method and device for reducing PAPR of a low-orbit satellite based on dynamic matching of beam patterns to eliminate or improve one or more defects existing in the prior art.

[0005] The first aspect of the present application provides a method for reducing PAPR of a low-orbit satellite based on dynamic matching of a beam pattern, the method comprising:

[0006] Constructing an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to the ephemeris position function; obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern;

[0007] Combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select a method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship;

[0008] Constructing a multi-user expected antenna beam pattern; matching the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, selecting one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern; adapting the most similar phased array antenna beam pattern with the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination;

[0009] A control function is obtained according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; a scaling function is established according to the scheduling period and the elevation angle change; the control function is updated and power adjustment is performed according to the scaling function to obtain a final beamforming signal.

[0010] In some embodiments of the present application, constructing an antenna beam pattern model for a given low-orbit satellite position and a given beam position according to the ephemeris position function includes:

[0011] The phased array is set as a planar array, and for the given wave position, a set of plane wave incident azimuth angles and a set of plane wave incident elevation angles between the array elements on the planar array and the center position are calculated through the ephemeris position function and the center position coordinates of the given wave position; a plurality of the array elements are selected to design a beamforming scheme and an antenna selection function is established; an antenna beam pattern model of the given wave position is established according to the set of plane wave incident azimuth angles, the set of plane wave incident elevation angles and the antenna selection function.

[0012] In some embodiments of the present application, the step of acquiring a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern includes:

[0013] The plane wave incident azimuth angle set and the plane wave incident elevation angle set are updated according to the ephemeris position function to obtain a new plane wave incident azimuth angle set and a new plane wave incident elevation angle set; the antenna beam pattern model is updated according to the new plane wave incident azimuth angle set and the new plane wave incident elevation angle set to obtain a dynamic low-orbit satellite phased array antenna beam pattern model.

[0014] In some embodiments of the present application, combining multiple groups of selected coding sequences and phase rotations in one beam pattern to reduce the PAPR of the FBMC signal according to respective corresponding reduction methods includes:

[0015] The multiple groups of selected coding sequences and the multiple groups of phase rotation combinations are randomly generated, wherein the multiple groups of selected coding sequences are used to reduce the PAPR of the FBMC signal, and the multiple groups of phase rotation combinations are used to reduce the PAPR of the FBMC signal.

[0016] In some embodiments of the present application, the mapping relationship between the dynamic optimal selection coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios is constructed according to the dynamic low-orbit satellite phased array antenna beam pattern model, including:

[0017] The different satellite launch scenarios are simulated by changing the ephemeris position function and the given wave position, and a mapping relationship between a dynamic optimal selection coding sequence and a dynamic optimal phase rotation combination under the different satellite launch scenarios is constructed according to the dynamic low-orbit satellite phased array antenna beam pattern model.

[0018] In some embodiments of the present application, the constructing of a multi-user expected antenna beam pattern; matching the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and selecting one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern, includes:

[0019] Designing a multi-user function, and constructing the multi-user expected antenna beam pattern based on the multi-user function;

[0020] The multi-user expected antenna beam pattern is matched with the dynamic low-orbit satellite phased array antenna beam pattern model, a matching function value is designed, and when the matching function value is minimum, one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern are selected.

[0021] In some embodiments of the present application, the acquiring a control function according to the multi-user optimal selected coding sequence and the multi-user optimal phase rotation combination includes:

[0022] A control function is obtained by performing a PTS operation to reduce the PAPR of the multi-user optimal selected coding sequence or a SLM operation to reduce the PAPR of the multi-user optimal phase rotation combination at an initial elevation angle.

[0023] A second aspect of the present application provides a low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns, the device comprising:

[0024] A model building module is used to build an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to an ephemeris position function; and obtain a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern;

[0025] A database construction module is used to combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select a method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; and construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship;

[0026] A multi-user processing module is used to construct a multi-user expected antenna beam pattern; match the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and select one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern; and adapt the most similar phased array antenna beam pattern to the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination;

[0027] A beamforming module is used to obtain a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establish a scaling function according to the scheduling period and the elevation angle change; update the control function and perform power adjustment according to the scaling function to obtain a final beamforming signal.

[0028] The third aspect of the present application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for reducing the PAPR of a low-orbit satellite based on dynamic matching of beam patterns mentioned in the aforementioned embodiment is implemented.

[0029] The fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns mentioned in the aforementioned embodiment.

[0030] The present application provides a method and device for reducing PAPR of low-orbit satellites based on dynamic matching of beam patterns, and the method includes: obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern; constructing an optimal matching database of different beam patterns and the corresponding optimal reduction strategy according to a mapping relationship; adapting the most similar phased array antenna beam pattern to the optimal matching database to obtain the corresponding multi-user optimal selection coding sequence and multi-user optimal phase rotation combination; obtaining a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establishing a scaling function according to the scheduling period and elevation angle change; updating the control function and performing power adjustment according to the scaling function to obtain the final beamforming signal. The present application can ensure the quality of FBMC waveforms and effectively reduce the peak-to-average ratio under phased array agile beams.

[0031] Additional advantages, purposes, and features of the present application will be partially described in the following description, and will become partially apparent to those skilled in the art after studying the following, or may be learned from the practice of the present application. The purposes and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0032] Those skilled in the art will understand that the purposes and advantages that can be achieved by the present application are not limited to the above specific description, and the above and other purposes that can be achieved by the present application will be more clearly understood based on the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and do not constitute a limitation of the present application. The components in the drawings are not drawn to scale, but are only for the purpose of illustrating the principles of the present application. In order to facilitate the illustration and description of some parts of the present application, the corresponding parts in the drawings may be enlarged, that is, they may become larger relative to other components in the exemplary device actually manufactured according to the present application. In the drawings:

[0034] Figure 11 is a flow chart of a method for reducing PAPR of a low-orbit satellite based on dynamic matching of beam patterns in one embodiment of the present application.

[0035] Figure 2 Schematic diagram of the structure of a low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns in another embodiment of the present application.

[0036] Definitions of Abbreviations and Key Terms

[0037] HPA High-Power Amplifier

[0038] PAPR Peak to Average Power Ratio (Peak to Average Power Ratio)

[0039] OFDM Orthogonal Frequency Division Multiplexing

[0040] UFMC Universal Filtered Multicarrier

[0041] GFDM Generalized Frequency Division Multiplexing

[0042] FBMC Filter Bank Multicarrier (Filter Bank Multicarrier)

[0043] OQAM offset quadrature amplitude modulation

[0044] SLM selective mapping

[0045] PTS Partial Transmission Sequence DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the implementation modes and the accompanying drawings. Here, the illustrative implementation modes and descriptions of the present application are used to explain the present application, but are not intended to limit the present application.

[0047] It should also be noted here that in order to avoid obscuring the present application due to unnecessary details, only the structures and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0048] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0049] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection with an intermediate.

[0050] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0051] The main focus of this application is the peak-to-average ratio suppression of the FBMC waveform for phased array low-orbit satellite Internet. Low-orbit satellite Internet has become the only means of 6G global high-speed mobile communication coverage. To achieve support for high-speed, large-scale users, and high-speed mobile communications, breakthrough innovations are needed in the satellite air interface communication system. To this end, integration with ground B5G or 5G new air interface, combined with phased array antennas, to achieve flexible and dynamic beamforming and scheduling, has become the main idea for innovation in the low-orbit satellite Internet communication system. At present, domestic and foreign research institutions have carried out research and demonstration of low-orbit satellite communication systems based on OFDM waveforms. Other B5G / 6G alternative waveforms, such as UFMC, GFDM, FBMC, etc., are also very potential for application in low-orbit satellite Internet. Because FBMC has obvious advantages over UFMC and GFDM in terms of design freedom, and other performance is comparable to the other two waveforms, the present invention mainly focuses on the FBMC waveform.

[0052] There have been studies on the peak-to-average ratio suppression of FBMC, mainly including the use of single carrier or constant envelope modulation, selected sequence modulation (SLM), phase rotation (PTS), clipping and other methods. The challenges of its application in low-orbit satellite Internet are: 1) In the phased array antenna of low-orbit satellites, multiple single carriers need to be merged. The existing single carrier modulation MF-TDMA or DFT-s-OFDM, or the single single carrier of the single-carrier constant envelope modulation will need to be merged, and the PAPR after merging will be significantly improved. 2) Due to the randomness of the sequence symbols, the existing PAPR suppression methods based on SLM and PTS require multiple attempts and iterations to traverse the optimal design for reducing PAPR, which is inefficient. In addition, the beam of the phased array low-orbit satellite will undergo sudden or continuous changes in the feeding direction due to the scheduling and movement of the beam position during the service cycle. The optimal design of the aforementioned PAPR will be difficult to meet the requirements of subsequent changes in PAPR reduction. 3) The existing direct clipping method can still maintain reliable demodulation performance during reception when the channel coding error correction capability is sufficient. However, due to the dynamic changes of phased array low-orbit satellites, the power covering the ground will also change. The fixed peak clipping threshold will lead to energy waste of the onboard power amplifier or excessive peak clipping, resulting in serious signal distortion.

[0053] In summary, our idea for applying FBMC to low-orbit satellite Internet is: considering that during the satellite service cycle, the feeding beam direction of the phased array antenna will continue to change in the direction of satellite movement in the form of several composite beams, and the control information of the above composite beam can be obtained in advance when different users reuse it. To this end, we can construct a series of phased array antenna beam patterns with agile beam pointing, select different PAPR reduction methods and configurations in the given phased array antenna beam pattern, and obtain the optimal PAPR suppression strategy under the current phased array antenna beam pattern through simulation, thereby constructing a database of phased array antenna beam patterns and optimal PAPR suppression strategies. When a phased array low-orbit satellite is in service, the transmitter can obtain the expected phased array antenna beam pattern based on the current user position and beam control information, and search for the most suitable PAPR reduction method and configuration for the phased array antenna beam pattern from the data. Accordingly, the transmitter calculates the gradual configuration method of the selected PAPR method and configuration as the satellite position changes based on the acquired ephemeris, thereby completing the optimal PAPR control of the phased array low-orbit satellite FBMC waveform according to the predetermined PAPR reduction method and configuration.

[0054] The technical problem that needs to be solved in this application is to ensure the quality of the FBMC waveform and effectively reduce the peak-to-average ratio under the phased array agile beam. Under the low-orbit phased array system, the waveform of the transmitted signal will form several schemes according to the distribution and scheduling requirements of ground users during the satellite service period, and the transmitted signal waveform gradually changes with the movement of the satellite. Therefore, the peak-to-average ratio of the phased array agile beam FBMC waveform also changes dynamically over time. In addition, the transmission link of the low-orbit satellite Internet is long and the delay is large. After the PAPR evaluation is performed after the received signal is fed back to the transmitter, there is often a problem of outdated feedback. Therefore, how to realize the on-demand automatic adjustment of the FBMC waveform peak-to-average ratio suppression strategy is the key to solving the problem of excessively high peak-to-average ratio of the phased array agile beam FBMC waveform. The key issues are as follows:

[0055] (1) Modeling of the beam pattern of phased array antenna with agile beam pointing: The satellite-borne phased array antenna can provide multiple dynamic, mobile, and agile beams to achieve flexible communication coverage. During the satellite service process, the beam pattern of the phased array antenna will form several beamforming schemes in one wave position according to the distribution of users on the ground. The direction of the beam will be obtained by the user's spatial coding information, which will form a combined beam in multiple antenna elements through the beamforming matrix. Therefore, how to combine user coding information and ephemeris information to construct a beam pattern in advance in the planned satellite wave position is the key to accurately control the FBMC multi-carrier after multiple single carriers are combined to reduce PAPR.

[0056] (2) Intelligent matching and adaptive control of PAPR reduction strategy: As the agile beam moves with the satellite, the waveform of the transmitted signal gradually changes, and the peak-to-average ratio of the agile beam FBMC waveform also changes dynamically over time. The transmission link of low-orbit satellite Internet is long and has a large delay. After the PAPR is evaluated after receiving the signal, it is fed back to the transmitter, which often causes the problem of outdated feedback. Therefore, it is possible to consider pre-matching the PAPR reduction scheme corresponding to the expected single-carrier input of the beam according to the design constraints of the phased array antenna beam pattern. At the same time, how to intelligently and dynamically adjust the configuration of the PAPR reduction scheme based on the matching PAPR reduction scheme is the key to solving the problem of on-demand automatic adjustment of the FBMC waveform peak-to-average ratio suppression strategy.

[0057] The details are described in detail through the following examples.

[0058] The embodiment of the present application provides a low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns, which can be performed by a low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns. Referring to the figure, the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns specifically includes the following contents:

[0059] Step 110: construct an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to the ephemeris position function; and obtain a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern.

[0060] Wherein, step 110 includes:

[0061] Step 010: Set the phased array as a planar array, and for the given wave position, calculate the plane wave incident azimuth angle set and the plane wave incident elevation angle set of the array elements on the plane array and the center position through the ephemeris position function and the center position coordinates of the given wave position; select a plurality of the array elements to design a beamforming scheme and establish an antenna selection function; and establish an antenna beam pattern model of the given wave position according to the plane wave incident azimuth angle set, the plane wave incident elevation angle set and the antenna selection function.

[0062] Step 020: According to the ephemeris position function, the plane wave incident azimuth angle set and the plane wave incident elevation angle set are updated to obtain a new plane wave incident azimuth angle set and a new plane wave incident elevation angle set; according to the new plane wave incident azimuth angle set and the new plane wave incident elevation angle set, the antenna beam pattern model is updated to obtain a dynamic low-orbit satellite phased array antenna beam pattern model.

[0063] Specifically,

[0064] Firstly, a plane rectangular coordinate system is established with a certain ground wave position center as the coordinate origin. The coordinates of the satellite in the coordinate system are calculated at different times according to the ephemeris information. Based on this coordinate, the position relationship of the satellite phased array relative to any given wave position at different times, namely the ephemeris position function, is obtained.

[0065] Secondly, the phased array used is set as a plane array, with array elements. Under the condition of ground predetermined wave positions, for a given wave position, the plane wave incident azimuth of each array element on the satellite phased array antenna to the center position of the given wave position is calculated through the ephemeris position function and the coordinates of the center position of the given wave position. and the plane wave incident pitch angle remember is the set of plane wave incident azimuths of all array elements to a given wave position, Ψ l =(θ 1,l ,θ 2,l ,……,θ M,l ) is the set of plane wave incident elevation angles of all array elements for a given wave position. Since the beamforming method and effect will change with the number of array elements used in the phased array antenna and the distribution of each element on the phased array, it is set to select several elements in the phased array antenna to design the beamforming scheme and establish the antenna selection function W m, the function is an M×1 matrix, each value of the matrix corresponds to the antenna selected by the beamforming scheme. When the array element is used, the value of the column is assigned to , otherwise it is assigned to . Select array elements for beamforming, then the total value of the column is assigned to . When the value of the column is assigned to , the corresponding and The value of is also assigned as. Then the function W is selected through the antenna m 、The incident azimuth angle set of the plane wave of the array element Φ l , the incident pitch angle set Ψ l Establish the antenna beam pattern model F for a given wave position m,l =f(W m ,Φ l ,Ψ l ).

[0066] Finally, for the above plane wave incident azimuth angle and the plane wave incident pitch angle Add the ephemeris position function P t As a constraint condition, we get the new plane wave incident azimuth set Φ t,l , the new plane wave incident pitch angle set Ψ t,l , thereby updating the above antenna beam pattern model to obtain the dynamic low-orbit satellite phased array antenna beam pattern model F t,l =f(W m ,Φ t,l ,Ψ t,l ).

[0067] Step 120: Combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select a method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; and construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship.

[0068] Wherein, step 120 comprises:

[0069] Step 030: randomly generate the multiple groups of selected coding sequences and the multiple groups of phase rotation combinations, wherein the multiple groups of selected coding sequences are used to reduce the PAPR of the FBMC signal, and the multiple groups of phase rotation combinations are used to reduce the PAPR of the FBMC signal.

[0070] Step 040: Simulate the different satellite launch scenarios by changing the ephemeris position function and the given wave position, and construct a mapping relationship between the dynamic optimal selection coding sequence and the dynamic optimal phase rotation combination under the different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model.

[0071] Specifically,

[0072] First, the frequency domain information sequence X = (X0, X1, ..., X N-1 ), divided into sub-block sequences (B1, B2, ..., B V ), and these sub-block sequences do not overlap each other, Design and select coding sequence B=(B1,B2,……,B V ) as the sub-block segmentation sequence of the method. At the same time, the phase rotation combination is designed As the phase rotation coefficient of the method. Among them, each phase rotation factor are all randomly generated. In order to reduce the computational complexity, we define (1≤n≤N). Multiple groups of selected coding sequences B and multiple groups of phase rotation combinations Θ are randomly generated, multiple groups of selected coding sequences are used to reduce the PAPR of the FBMC signal, and multiple groups of phase rotation combinations are used to reduce the PAPR of the FBMC signal. The method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method are selected as the optimal reduction strategy as follows:

[0073]

[0074] Wherein, parameter D represents the selection of coding sequence B or phase rotation combination Θ, and G(·) is a function for calculating the frequency domain sequence after the operation using coding sequence B or the operation using phase rotation coefficient Θ.

[0075] Secondly, by changing the satellite motion position (x t ,y t ,z t ) and selected multi-wavelength (Set the number of multi-wavelength positions to ), simulate different satellite launch scenarios. Based on the dynamic low-orbit satellite phased array antenna beam pattern model, record the multi-wavelength position situation = l, calculate the dynamic optimal selection coding sequence under each beam pattern and dynamic optimal phase rotation combination The mapping relationship is constructed as follows:

[0076]

[0077] Finally, the different dynamic optimal selection encoding sequences and dynamic optimal phase rotation combination With different beam patterns F t,l The mapping relationships under are summarized and sorted by scene, and the optimal matching database of different beam patterns and corresponding optimal reduction strategies is constructed as follows

[0078]

[0079] Among them C t,l The subscript indicates the time of signal transmission, and corresponding to different satellite positions, the subscript indicates different wave positions.

[0080] Step 130: construct a multi-user expected antenna beam pattern; match the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and select one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern; adapt the most similar phased array antenna beam pattern to the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination.

[0081] Wherein step 130 comprises:

[0082] Step 050: Design a multi-user function, and construct the multi-user expected antenna beam pattern based on the multi-user function; match the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, design a matching function value, and select one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern when the matching function value is minimum.

[0083] Specifically,

[0084] First, for the multi-user case with a number of users, the multi-user function U is designed using the synthesized antenna beam pattern. n =(u1,u2,……,u n ). This function passes u k The value of (1≤k≤n) determines the signal power weight of each user at the corresponding angle on the antenna pattern. Based on this function, the multi-user expected antenna beam pattern F is constructed. M =f'(U n )

[0085] Secondly, the above multi-user expected antenna beam pattern F M Compared with the above dynamic low-orbit satellite phased array antenna beam pattern model F t,l Perform matching and design matching function value

[0086] Among them, hi (F M ,F t,l ) Calculate the antenna beam pattern F M and F t,l The power difference at the user angle is multiplied by the weight ai as the weighted power difference at the user angle. The matching function value H is the sum of the weighted power differences at the user angles. Therefore, the matching function value H reflects the antenna beam pattern F M and F t,l The lower the final H value, the closer the two antenna beam patterns are in function, that is, the higher the similarity level. Calculate the antenna beam pattern F established for each pair of beam centers in the database t,l and the multi-user expected antenna beam pattern F M , find the one or two with the lowest value that corresponds to the most similar phased array antenna beam pattern F t,l .

[0087] The above matching process is the meaning of dynamic matching in the method name.

[0088] Finally, the most similar phased array antenna beam pattern is denoted as F match , by comparing with the optimal matching database obtained in step Adapt and obtain the corresponding multi-user optimal selection coding sequence B match Or the optimal phase rotation combination Θ for multiple users match , the specific formula is as follows:

[0089]

[0090] Step 140: Acquire a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establish a scaling function according to the scheduling period and the elevation angle change; update the control function and perform power adjustment according to the scaling function to obtain a final beamforming signal.

[0091] Wherein step 140 comprises:

[0092] Step 060: Perform a PTS operation to reduce the PAPR of the multi-user optimal selected coding sequence at the initial elevation angle or perform a SLM operation to reduce the PAPR of the multi-user optimal phase rotation combination to obtain a control function.

[0093] Specifically,

[0094] First, the transmitting end signal is processed: at the initial elevation angle Next, the optimal selection of the coding sequence B for the multi-user in step match Do PTS or multi-user optimal phase rotation combination Θ matchThe control function for performing SLM to reduce PAPR operation is as follows:

[0095] x n =g(D match ,X),(D match =B match orΘ match )

[0096] Among them, g(·) represents the function of performing the above operation on the frequency domain sequence, and the final time domain signal x n The value will decrease.

[0097] Secondly, set the scheduling period as the change period of the reduction strategy, the elevation angle between the satellite and the receiving end The received signal changes accordingly. Establish a scaling function based on the change in satellite elevation angle as follows:

[0098]

[0099] Among them, z n (1≤n≤N p ) represents the scaling factor on the th array element. In () the initial elevation angle In the case of In each scheduling cycle, keep matching the most similar phased array antenna beam pattern F match and its adaptation to multi-user optimal selection coding sequence B match Or the optimal phase rotation combination Θ for multiple users match And the scaling function The parameters of the next scheduling cycle are predicted according to the ephemeris information, and the operation of the steps is repeated, and after a scheduling cycle, a new reduction strategy is replaced.

[0100]

[0101] Among them, F n It refers to the most similar phased array antenna beam pattern obtained by matching the optimal matching database in step in the th scheduling period.

[0102] Finally, update the above control function f(·) according to the scaling function After power adjustment, the final beamforming signal is as follows:

[0103]

[0104] In summary, the present application provides a method and device for reducing PAPR of low-orbit satellites based on dynamic matching of beam patterns, and the method includes: obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern; constructing an optimal matching database of different beam patterns and the corresponding optimal reduction strategy according to a mapping relationship; adapting the most similar phased array antenna beam pattern to the optimal matching database to obtain the corresponding multi-user optimal selection coding sequence and multi-user optimal phase rotation combination; obtaining a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establishing a scaling function according to the scheduling period and elevation angle change; updating the control function and performing power adjustment according to the scaling function to obtain the final beamforming signal. The present application can ensure the quality of FBMC waveforms and effectively reduce the peak-to-average ratio under phased array agile beams.

[0105] From the software level, the present application also provides a low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns for executing all or part of the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns. Referring to the figure, the low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns specifically includes the following contents:

[0106] The model building module 10 is used to build an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to the ephemeris position function; and obtain a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern;

[0107] The database construction module 20 is used to combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select the method that makes the PAPR of the FBMC signal the lowest and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; and construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship;

[0108] The multi-user processing module 30 is used to construct a multi-user expected antenna beam pattern; match the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and select one or two most similar phased array antenna beam patterns with the highest similarity level to the multi-user expected antenna beam pattern; and adapt the most similar phased array antenna beam pattern to the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination;

[0109] The beamforming module 40 is used to obtain a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establish a scaling function according to the scheduling period and the elevation angle change; update the control function and perform power adjustment according to the scaling function to obtain a final beamforming signal.

[0110] The embodiment of the present application also provides an electronic device, such as a central server, which may include a processor, a memory, a receiver and a transmitter, wherein the processor is used to execute the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns mentioned in the above embodiment, wherein the processor and the memory may be connected via a bus or other means, such as by bus connection. The receiver may be connected to the processor and the memory via wired or wireless means.

[0111] The processor may be a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a combination of the above chips.

[0112] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs, non-transitory computer executable programs and modules, such as the program instructions / modules corresponding to the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns in the embodiment of the present application. The processor executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions and modules stored in the memory, that is, the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns in the above method embodiment is implemented.

[0113] The memory may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the processor, etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0114] The one or more modules are stored in the memory, and when executed by the processor, the Internet of Things intrusion detection model training method and / or the Internet of Things intrusion personalized detection method in the embodiment are executed.

[0115] In some embodiments of the present application, the user equipment may include a processor, a memory, and a transceiver unit, which may include a receiver and a transmitter. The processor, memory, receiver, and transmitter may be connected through a bus system. The memory is used to store computer instructions, and the processor is used to execute the computer instructions stored in the memory to control the transceiver unit to send and receive signals.

[0116] As an implementation method, the functions of the receiver and the transmitter in the present application can be considered to be implemented through a transceiver circuit or a dedicated chip for transceiver, and the processor can be considered to be implemented through a dedicated processing chip, a processing circuit or a general chip.

[0117] As another implementation method, it is possible to use a general-purpose computer to implement the server provided in the embodiment of the present application, that is, to store the program code for implementing the functions of the processor, receiver, and transmitter in a memory, and the general-purpose processor implements the functions of the processor, receiver, and transmitter by executing the code in the memory.

[0118] The embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the low-orbit satellite PAPR reduction method based on dynamic matching of beam patterns mentioned in the above embodiment are implemented. The computer-readable storage medium can be a tangible storage medium, such as a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a floppy disk, a hard disk, a removable storage disk, a CD-ROM, or any other form of storage medium known in the technical field.

[0119] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software or a combination of the two. Whether it is specifically performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of this application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier.

[0120] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0121] In the present application, features described and / or illustrated for one embodiment may be used in the same manner or in a similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0122] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the embodiments of the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns, characterized in that: The method includes: Constructing an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to the ephemeris position function; obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern; Combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select a method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship; Constructing a multi-user expected antenna beam pattern; matching the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and selecting the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern; adapting the most similar phased array antenna beam pattern with the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination; Acquire a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establish a scaling function according to the scheduling period and the elevation angle change; update the control function and perform power adjustment according to the scaling function to obtain a final beamforming signal; The step of constructing a multi-user expected antenna beam pattern; matching the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and selecting the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern, includes: Designing a multi-user function, and constructing the multi-user expected antenna beam pattern based on the multi-user function; The multi-user expected antenna beam pattern is matched with the dynamic low-orbit satellite phased array antenna beam pattern model, a matching function value is designed, and when the matching function value is minimum, the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern is selected.

2. The method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns according to claim 1, characterized in that: The step of constructing an antenna beam pattern model for a given low-orbit satellite position and a given beam position according to the ephemeris position function includes: The phased array is set as a planar array, and for the given wave position, a set of plane wave incident azimuth angles and a set of plane wave incident elevation angles between the array elements on the planar array and the center position are calculated through the ephemeris position function and the center position coordinates of the given wave position; a plurality of array elements are selected to design a beamforming scheme and an antenna selection function is established; an antenna beam pattern model of the given wave position is established according to the set of plane wave incident azimuth angles, the set of plane wave incident elevation angles and the antenna selection function.

3. The method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns according to claim 2, characterized in that: The step of obtaining a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern includes: The plane wave incident azimuth angle set and the plane wave incident elevation angle set are updated according to the ephemeris position function to obtain a new plane wave incident azimuth angle set and a new plane wave incident elevation angle set; the antenna beam pattern model is updated according to the new plane wave incident azimuth angle set and the new plane wave incident elevation angle set to obtain a dynamic low-orbit satellite phased array antenna beam pattern model.

4. The method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns according to claim 1, characterized in that: The method of combining multiple groups of selected coding sequences and phase rotations in one beam pattern to reduce the PAPR of the FBMC signal in accordance with respective corresponding reduction methods includes: The multiple groups of selected coding sequences and the multiple groups of phase rotation combinations are randomly generated, wherein the multiple groups of selected coding sequences are used to reduce the PAPR of the FBMC signal, and the multiple groups of phase rotation combinations are used to reduce the PAPR of the FBMC signal.

5. The method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns according to claim 1, characterized in that: The mapping relationship between the dynamic optimal selection coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios is constructed according to the dynamic low-orbit satellite phased array antenna beam pattern model, including: The different satellite launch scenarios are simulated by changing the ephemeris position function and the given wave position, and a mapping relationship between a dynamic optimal selection coding sequence and a dynamic optimal phase rotation combination under the different satellite launch scenarios is constructed according to the dynamic low-orbit satellite phased array antenna beam pattern model.

6. The method for reducing PAPR of low-orbit satellite based on dynamic matching of beam patterns according to claim 1, characterized in that: The acquiring a control function according to the multi-user optimal selected coding sequence and the multi-user optimal phase rotation combination comprises: A control function is obtained by performing a PTS operation to reduce the PAPR of the multi-user optimal selected coding sequence or a SLM operation to reduce the PAPR of the multi-user optimal phase rotation combination at an initial elevation angle.

7. A low-orbit satellite PAPR reduction device based on dynamic matching of beam patterns, characterized in that: The device includes: A model building module is used to build an antenna beam pattern model for a given low-orbit satellite position and a given wave position according to an ephemeris position function; and obtain a dynamic low-orbit satellite phased array antenna beam pattern model according to the antenna beam pattern; A database construction module is used to combine multiple groups of selected coding sequences and phase rotations in a beam pattern to reduce the PAPR of the FBMC signal according to their respective corresponding reduction methods, calculate and select a method that minimizes the PAPR of the FBMC signal and the optimal selected coding sequence and optimal phase rotation combination used in the method as the optimal reduction strategy; construct a mapping relationship between the dynamic optimal selected coding sequence and the dynamic optimal phase rotation combination under different satellite launch scenarios according to the dynamic low-orbit satellite phased array antenna beam pattern model; and construct an optimal matching database of different beam patterns and the corresponding optimal reduction strategies according to the mapping relationship; A multi-user processing module is used to construct a multi-user expected antenna beam pattern; match the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and select the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern; and adapt the most similar phased array antenna beam pattern to the optimal matching database to obtain a corresponding multi-user optimal selection coding sequence and a multi-user optimal phase rotation combination; A beamforming module, configured to obtain a control function according to the multi-user optimal selection coding sequence and the multi-user optimal phase rotation combination; establish a scaling function according to the scheduling period and the elevation angle change; update the control function and perform power adjustment according to the scaling function to obtain a final beamforming signal; The step of constructing a multi-user expected antenna beam pattern; matching the multi-user expected antenna beam pattern with the dynamic low-orbit satellite phased array antenna beam pattern model, and selecting the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern, includes: Designing a multi-user function, and constructing the multi-user expected antenna beam pattern based on the multi-user function; The multi-user expected antenna beam pattern is matched with the dynamic low-orbit satellite phased array antenna beam pattern model, a matching function value is designed, and when the matching function value is minimum, the most similar phased array antenna beam pattern with the highest similarity level to the multi-user expected antenna beam pattern is selected.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for reducing PAPR of a low-orbit satellite based on dynamic matching of beam patterns as described in any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for reducing PAPR of a low-orbit satellite based on dynamic matching of beam patterns as described in any one of claims 1 to 6 is implemented.

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