High-order cumulant blind equalization methods, devices, equipment, media and products

Abstract

This invention relates to the field of signal processing technology, and provides a method, apparatus, device, medium, and product for high-order cumulant blind equalization. The method includes: modeling the received signal as a cubic function with nonlinear distortion; calculating a theoretical high-order cumulant containing cubic function coefficients; substituting the actual high-order cumulant into the theoretical high-order cumulant to determine the cubic function coefficients; and compensating the received signal for nonlinear distortion based on the cubic function with determined coefficients. This invention effectively solves the signal synchronization and demodulation problems caused by power amplifier nonlinear distortion, providing an effective way to improve satellite signal reception quality.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and more specifically, to a high-order cumulant blind equalization method, apparatus, device, medium, and product. Background Technology

[0002] To overcome group delay distortion caused by the non-ideal characteristics of radio frequency devices, blind equalization technology plays a crucial role in satellite communication. In engineering practice, signal distortion and signal quality are typically reduced and improved through either transmitter pre-distortion or receiver equalization, thereby ensuring the stable and efficient operation of the communication system. Receiver equalization technology uses a specially designed equalizer to post-process distorted signals to restore their quality. Under bandwidth-constrained conditions, increasing the modulation order is an effective way to enhance the spectral efficiency and transmission rate of wireless broadband data transmission systems, but this also leads to an increase in the peak-to-average power ratio (PAPR), making the distortion problem caused by channel nonlinearity more prominent. In high-speed data transmission scenarios using small satellite networks, the transmit power has an upper limit due to satellite size and payload limitations. To obtain sufficient power, traveling-wave tube amplifiers (TWTAs) often operate near their saturation point. At this time, high-power amplifiers (HPAs) can induce AM / AM (Amplitude Modulation to Amplitude Modulation) and AM / PM (Amplitude Modulation to Phase Modulation) effects, causing nonlinear signal distortion. With the rapid growth of satellite communication data volume, the multiple stages that signals undergo during satellite-to-ground transmission have led to increasingly severe nonlinear distortion. Currently, satellite communication systems must simultaneously address the combined effects of linear and nonlinear distortion. Therefore, when receiving broadband high-speed signals, joint compensation for these two types of distortion is necessary to significantly improve receiver performance. Blind equalization, as a channel compensation technique at the receiver end, can effectively compensate for channel characteristics and suppress inter-symbol interference without prior acquisition of channel information, making it of significant value in improving the performance of high-speed satellite communication systems. Summary of the Invention

[0003] The present invention aims to provide a high-order cumulant blind equalization method, apparatus, device, medium and product to solve the signal synchronization and demodulation problems caused by power amplifier nonlinear distortion.

[0004] In a first aspect, the present invention provides a high-order cumulant blind equalization method, comprising: The received signal is modeled as a cubic function with nonlinear distortion, and the theoretical higher-order cumulants containing the coefficients of the cubic function are calculated. Substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve the problem and determine the coefficients of the cubic function. Nonlinear distortion compensation of the received signal is performed using a cubic function with deterministic coefficients.

[0005] In a preferred embodiment, the nonlinear distortion modeling of the received signal is a cubic function, and the calculation of the theoretical higher-order cumulants containing the cubic function coefficients includes: The received signal is approximated using a cubic function, which includes the second and third coefficients of the cubic function. The theoretical higher-order cumulants of a cubic function are calculated based on higher-order moments, including theoretical second-order cumulants and theoretical fourth-order cumulants; both theoretical second-order cumulants and theoretical fourth-order cumulants contain the second-order and third-order coefficients of the cubic function.

[0006] In a preferred embodiment, the values ​​of the higher-order moments are calculated in advance based on the signal type.

[0007] In a preferred embodiment, the signal type includes QPSK, 8PSK, 16QAM, 16APSK, and 32QAM.

[0008] In a preferred embodiment, the step of substituting the actual higher-order cumulants into the theoretical higher-order cumulants to determine the coefficients of the cubic function includes: The actual second-order cumulant and the actual fourth-order cumulant are calculated based on the received signal. By substituting the actual second-order cumulants into the theoretical second-order cumulants, and the actual fourth-order cumulants into the theoretical fourth-order cumulants, the second-order and third-order coefficients of the cubic function can be determined by solving the system of equations.

[0009] In a preferred embodiment, the nonlinear distortion compensation of the received signal based on a cubic function with deterministic coefficients includes: Find the inverse function of the cubic function; Then, the inverse function is used to compensate for nonlinear distortion of the received signal.

[0010] Secondly, the present invention provides a high-order cumulative quantity blind equalization device, comprising: The first processing unit is used to model the received signal as a cubic function with nonlinear distortion and to calculate the theoretical higher-order cumulants containing the coefficients of the cubic function. The second processing unit is used to substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve for the coefficients of the cubic function. The third processing unit is used to perform nonlinear distortion compensation on the received signal based on a cubic function with deterministic coefficients.

[0011] Thirdly, the present invention provides an electronic device, comprising: At least one processor; and a memory communicatively connected to said at least one processor; The memory stores instructions that can be executed by the at least one processor, and the at least one processor executes the instructions stored in the memory to perform the above-described method.

[0012] Fourthly, the present invention provides a computer-readable storage medium for storing instructions that, when executed, cause the above-described method to be implemented.

[0013] Fifthly, the present invention provides a computer program product that, when invoked by a computer, causes the computer to execute the above-described method.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This invention models a real nonlinear system as a cubic function, leveraging the advantage that higher-order cumulants can reflect the system's nonlinear characteristics without relying on pilot sequences. By calculating the actual and theoretical higher-order cumulants, a system of equations is constructed to solve for the cubic function coefficients. The inverse function of the cubic function is then used to compensate for power amplifier distortion in the received signal, followed by synchronized signal reception. Experimental results show that, under different modulation schemes, the fitting accuracy of the proposed method for power amplifier distortion improves with increasing signal-to-noise ratio (SNR), achieving approximate fitting at a 20dB SNR. The output constellation diagram obtained after synchronization is quite ideal. Simultaneously, the bit error rate of the compensated signal is significantly improved, effectively solving the signal synchronization and demodulation problems caused by power amplifier nonlinear distortion, and providing an effective way to improve satellite signal reception quality. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating a high-order cumulant blind equalization method applied to the receiver of a satellite communication system, as provided in an embodiment of the present invention.

[0016] Figure 2 A flowchart of a high-order cumulant blind equilibrium method provided in an embodiment of the present invention.

[0017] Figure 3 This is a magnified constellation diagram of 16APSK in an embodiment of the present invention.

[0018] Figure 4 This is a constellation diagram after 16APSK equalization in an embodiment of the present invention.

[0019] Figure 5 This is a magnified constellation diagram of 16QAM in an embodiment of the present invention.

[0020] Figure 6 This is the constellation diagram after 16QAM equalization in an embodiment of the present invention.

[0021] Figure 7 This is a schematic diagram of a high-order cumulant blind equalization device provided in an embodiment of the present invention.

[0022] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] like Figure 1 As shown, this embodiment of the invention provides a high-order cumulant blind equalization method, applied to the receiver of a satellite communication system, which performs nonlinear compensation, matched filtering, and synchronous reception on the received signal after passing through the source, shaping filter, and high-power amplifier.

[0026] like Figure 2 As shown in the figure, an embodiment of the present invention provides a high-order cumulant blind equalization method, which includes the following steps: S100 models the received signal as a cubic function with nonlinear distortion and calculates the theoretical higher-order cumulants containing the coefficients of the cubic function. S200, substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve for the coefficients of the cubic function; S300 performs nonlinear distortion compensation (power amplifier distortion compensation) on the received signal based on a cubic function with deterministic coefficients.

[0027] The following is a detailed illustrative description of a high-order cumulant blind equilibrium method provided by an embodiment of the present invention.

[0028] S100 models the received signal as a cubic function with nonlinear distortion and calculates the theoretical higher-order cumulants containing the coefficients of the cubic function. Modulated signals transmitted via satellite channels The input is a high-power amplifier, and the satellite channel exhibits nonlinear effects; additive white Gaussian noise (AWGN) is superimposed on the output signal of the high-power amplifier to obtain the received signal. First, the received signal can be Approximate using a cubic function Indicate:

[0029] in, Indicates the modulated signal. Denotes the second coefficients of a cubic function. The coefficients of a cubic function are represented by the third-order coefficients.

[0030] Then, the theoretical higher-order cumulants of the cubic function are calculated based on the higher-order moments, including the theoretical second-order cumulants and the theoretical fourth-order cumulants; both the theoretical second-order cumulants and the theoretical fourth-order cumulants contain the second-order and third-order coefficients of the cubic function. Specifically: For the cubic function of the received signal The formula for calculating its second-order cumulant is:

[0031] Where E represents the expected value.

[0032] The cubic function of the received signal Substituting into the formula for calculating second-order cumulants, we obtain the second-order cumulant, expressed as:

[0033] because exist hour, and Linearly uncorrelated, i.e. =0, therefore the theoretical second-order cumulant expression can be written as:

[0034] The expression for higher-order moments is:

[0035]

[0036]

[0037] Therefore, the cubic function of the received signal is calculated based on the higher-order moments. The theoretical second-order cumulant can be expressed as:

[0038] Similarly, the cubic function of the received signal can be calculated based on higher-order moments. The theoretical fourth-order cumulant is expressed as:

[0039] The values ​​of higher-order moments can be calculated in advance based on the type of modulation signal. The higher-order moments of the modulation signal are shown in Table 1.

[0040] Table 1. Theoretical values ​​of higher-order moments for various modulation signals

[0041] The signal types are explained below: Quadrature Phase Shift Keying (QPSK); 8PSK (8-Phase Shift Keying); 16QAM (16-ary Quadrature Amplitude Modulation) 16APSK (16-ary Amplitude Phase Shift Keying).

[0042] It should be noted that the above modulation signal types are only examples in the embodiments of the present invention. Other modulation signal types, such as 32QAM, are also supported in practical applications.

[0043] S200, substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve for the coefficients of the cubic function; First, based on the received signal The actual second-order cumulant and the actual fourth-order cumulant can be calculated at the receiving end and expressed as follows:

[0044]

[0045] By substituting the actual second-order cumulants into the theoretical second-order cumulants, and the actual fourth-order cumulants into the theoretical fourth-order cumulants, the second-order coefficients of the cubic function can be determined by solving the system of equations. and the third coefficients of a cubic function .

[0046] S300 performs nonlinear distortion compensation on the received signal based on a cubic function with deterministic coefficients.

[0047] After determining the second coefficients of the cubic function and the third coefficients of a cubic function Then, the inverse function of the cubic function can be calculated. In this embodiment of the invention, the finverse function in Matlab is used to calculate the inverse function of the cubic function. Then, the inverse function is used to compensate for nonlinear distortion of the received signal. After the nonlinear distortion is compensated, the linearity of the signal is restored, and matched filtering and synchronous reception at the receiving end can continue to be performed, thereby achieving accurate signal reception in satellite communication.

[0048] In the simulation experiment, 16APSK and 16QAM modulated signals were used, passing through a satellite channel model containing a nonlinear high-power amplifier. After executing the method described in this embodiment according to steps S100 to S300 above, as follows... Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, the diffuse constellation diagram after blind equalization is significantly improved, with a clear clustering effect, verifying its effectiveness in combating nonlinear distortion.

[0049] Based on the same technological concept, such as Figure 7 As shown, this embodiment of the invention also provides a high-order cumulant blind equalization device, comprising: The first processing unit is used to model the received signal as a cubic function with nonlinear distortion and to calculate the theoretical higher-order cumulants containing the coefficients of the cubic function. The second processing unit is used to substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve for the coefficients of the cubic function. The third processing unit is used to perform nonlinear distortion compensation on the received signal based on a cubic function with deterministic coefficients.

[0050] The working principle of each processing unit in the above device can be referred to the description in the foregoing method embodiments, and will not be repeated here.

[0051] Based on the same technical concept, embodiments of the present invention also provide an electronic device that can implement the high-order cumulant blind equalization method flow provided in the above embodiments of the present invention. In one embodiment, the electronic device may be a server, a terminal device, or other electronic device. Figure 8 As shown, the electronic device may include: At least one processor and a memory connected to the at least one processor. In this embodiment of the invention, the specific connection medium between the processor and the memory is not limited. Figure 8 The example used is the connection between the processor and memory via a bus. The bus... Figure 8 The connections between other components are indicated by thick lines and are for illustrative purposes only, not as limiting information. Buses can be divided into address buses, data buses, control buses, etc., but for ease of representation, [the specific bus type is not shown here]. Figure 8The processor is represented by a single thick line, but this does not imply that there is only one bus or one type of bus. Alternatively, a processor can also be called a controller; there are no restrictions on the name.

[0052] In this embodiment of the invention, the memory stores instructions that can be executed by at least one processor. By executing the instructions stored in the memory, at least one processor can execute a high-order cumulant blind equalization method as described above.

[0053] The processor is the control center of the device. It can connect to various parts of the control device through various interfaces and lines. By running or executing instructions stored in memory and calling data stored in memory, it can monitor the device's various functions and process data, thereby enabling overall monitoring of the device.

[0054] In an alternative design, the processor may include one or more processing units. The processor may integrate an application processor and a modem processor, wherein the application processor primarily handles the operating system, user interface, and applications, while the modem processor primarily handles wireless communication. It is understood that the modem processor may also not be integrated into the processor. In some embodiments, the processor and memory may be implemented on the same chip; in some embodiments, they may also be implemented separately on separate chips.

[0055] The processor can be a general-purpose processor, such as a CPU, digital signal processor, application-specific integrated circuit, field-programmable gate array or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the high-order cumulative quantity blind equalization method disclosed in the embodiments of this invention can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0056] Memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory can include at least one type of storage medium, such as flash memory, hard disk, multimedia card, card-type memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, magnetic disk, optical disk, etc. Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. In embodiments of the present invention, memory can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0057] By designing and programming the processor, the code corresponding to the high-order cumulative quantity blind equalization method described in the foregoing embodiments can be embedded into the chip, enabling the chip to execute the steps of the method described in the foregoing embodiments during operation. How to design and program the processor is a technique well-known to those skilled in the art and will not be elaborated upon here.

[0058] Based on the same inventive concept, embodiments of the present invention also provide a storage medium storing computer instructions that, when executed on a computer, cause the computer to perform a high-order cumulative blind equalization method described above.

[0059] In some alternative embodiments, the present invention also provides that various aspects of a higher-order cumulative blind equalization method can also be implemented as a program product comprising program code that, when the program product is run on a device, causes the control device to perform the steps in a higher-order cumulative blind equalization method according to various exemplary embodiments of the present invention as described above.

[0060] It should be noted that although several units or sub-units of the apparatus have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the invention, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units. Furthermore, although the operation of the method of the invention is described in a specific order in the drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0061] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0062] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a server, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0063] Program code for performing the operations of this invention can be written using any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0064] In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0065] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0066] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-order cumulant blind equilibrium method, characterized in that, include: The received signal is modeled as a cubic function with nonlinear distortion, and the theoretical higher-order cumulants containing the coefficients of the cubic function are calculated. Substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve the problem and determine the coefficients of the cubic function. Nonlinear distortion compensation of the received signal is performed using a cubic function with deterministic coefficients.

2. The high-order cumulant blind equalization method according to claim 1, characterized in that, The nonlinear distortion modeling of the received signal is a cubic function, and the calculation of theoretical higher-order cumulants containing the cubic function coefficients includes: The received signal is approximated using a cubic function, which includes the second and third coefficients of the cubic function. The theoretical higher-order cumulants of a cubic function are calculated based on higher-order moments, including theoretical second-order cumulants and theoretical fourth-order cumulants; both theoretical second-order cumulants and theoretical fourth-order cumulants contain the second-order and third-order coefficients of the cubic function.

3. The high-order cumulant blind equalization method according to claim 2, characterized in that, The values ​​of the higher-order moments are calculated in advance based on the signal type.

4. The high-order cumulant blind equalization method according to claim 3, characterized in that, The signal types include QPSK, 8PSK, 16QAM, 16APSK, and 32QAM.

5. The high-order cumulant blind equalization method according to claim 2, characterized in that, The step of substituting actual higher-order cumulants into theoretical higher-order cumulants to determine the coefficients of the cubic function includes: The actual second-order cumulant and the actual fourth-order cumulant are calculated based on the received signal. By substituting the actual second-order cumulants into the theoretical second-order cumulants, and the actual fourth-order cumulants into the theoretical fourth-order cumulants, the second-order and third-order coefficients of the cubic function can be determined by solving the system of equations.

6. The high-order cumulant blind equalization method according to claim 1, characterized in that, The nonlinear distortion compensation of the received signal based on a cubic function with deterministic coefficients includes: Find the inverse function of the cubic function; Then, the inverse function is used to compensate for nonlinear distortion of the received signal.

7. A high-order cumulant blind equalization device, characterized in that, include: The first processing unit is used to model the received signal as a cubic function with nonlinear distortion and to calculate the theoretical higher-order cumulants containing the coefficients of the cubic function. The second processing unit is used to substitute the actual higher-order cumulants into the theoretical higher-order cumulants to solve for the coefficients of the cubic function. The third processing unit is used to perform nonlinear distortion compensation on the received signal based on a cubic function with deterministic coefficients.

8. An electronic device, characterized in that, include: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor, which executes the instructions stored in the memory to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store instructions that, when executed, cause the method as described in any one of claims 1-6 to be implemented.

10. A computer program product, characterized in that, When the computer program product is invoked by a computer, it causes the computer to perform the method as described in any one of claims 1-6.

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