阅读说明：本技术 基于时域波形误差负反馈实现信号evm校正的方法、系统、装置、处理器及其存储介质 (Method, system, device, processor and storage medium for realizing signal EVM correction based on time domain waveform error negative feedback ) 是由 刘景鑫 于 2020-12-23 设计创作，主要内容包括：本发明涉及一种基于时域波形误差负反馈实现信号EVM校正的方法,包括以下步骤：通过期望波形和原始失真波形得到误差波形；通过失真波形和误差波形训练滤波器系数,得到使滤波器输出趋近于误差波形的系数；通过系数对失真信号进行校正补偿。本发明还涉及一种基于时域波形误差负反馈实现信号EVM校正的系统、装置、处理器及其计算可读存储介质采用了本发明的基于时域波形误差负反馈实现信号EVM校正的方法、系统、装置、处理器及其计算可读存储介质,能够快速校正硬件电路带来的信号失真,实时性能好,本发明能满足大带宽情况下高处理速率的要求,处理带宽大,本发明既适用于接收机也适用于发射机,应用范围广。(The invention relates to a method for realizing signal EVM correction based on time domain waveform error negative feedback, which comprises the following steps: obtaining an error waveform through the expected waveform and the original distorted waveform; training a filter coefficient through a distortion waveform and an error waveform to obtain a coefficient which enables the output of the filter to approach the error waveform; and correcting and compensating the distortion signal through the coefficient. The invention also relates to a system, a device, a processor and a computer readable storage medium for realizing signal EVM correction based on time domain waveform error negative feedback, which adopt the method, the system, the device, the processor and the computer readable storage medium for realizing signal EVM correction based on time domain waveform error negative feedback of the invention, can quickly correct signal distortion brought by a hardware circuit, and has good real-time performance.)

1. A method for realizing signal EVM correction based on time domain waveform error negative feedback is characterized by comprising the following steps:

(1) obtaining an error waveform through the expected waveform and the original distorted waveform;

(2) training a filter coefficient through a distortion waveform and an error waveform to obtain a coefficient which enables the output of the filter to approach the error waveform;

(3) and correcting and compensating the distortion signal through the coefficient.

2. The method for realizing signal EVM correction based on time-domain waveform error negative feedback according to claim 1, wherein the step (1) specifically comprises the following steps:

(1.1) acquiring a distorted signal time domain waveform;

(1.2) calculating to obtain expected waveforms with consistent phases according to the modulation types;

and (1.3) subtracting the original distorted signal waveform from the expected waveform to obtain an error waveform.

3. The method for realizing signal EVM correction based on time-domain waveform error negative feedback according to claim 1, wherein the step (2) specifically comprises the following steps:

(2.1) outputting the distortion waveform as an input sequence and the error waveform as a target;

and (2.2) obtaining a coefficient which enables the output of the filter to approach an error waveform through continuous iterative training.

4. The method for realizing signal EVM correction based on time-domain waveform error negative feedback according to claim 1, wherein the step (3) specifically comprises the following steps:

(3.1) carrying out parallelization processing on the distortion data, and dividing the parallelization data into multiple paths;

(3.2) carrying out convolution operation on the multi-channel parallelization data and the trained filter coefficient;

(3.3) carrying out parallelization combination on the calculated data to obtain an error waveform corresponding to the input end distortion waveform;

(3.4) carrying out time delay operation on the input distortion data;

and (3.5) carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

5. The method for implementing signal EVM correction based on time-domain waveform error negative feedback according to claim 1, wherein the filter coefficients obtained in the step (2) are specifically:

the filter coefficients are obtained according to the following formula:

Δw_n＝e×conj(x_n)；

where e is the difference between the desired output and the actual output, x_nTo input data, w_nAre the filter coefficients.

6. A system for realizing signal EVM correction based on time domain waveform error negative feedback is characterized by comprising:

the parallelization module is used for performing parallelization processing on the distortion data and dividing the parallelization data into multiple paths of parallelization data;

the operation unit group comprises a plurality of operation units which are connected with the parallelization module, and each operation unit receives one path of parallelization data output by the parallelization module and performs convolution operation with the trained filter coefficient;

the merging module is connected with the operation unit group and used for carrying out parallel merging on the operated data to obtain an error waveform corresponding to the input end distortion waveform;

the time delay module is connected with the parallelization module and is used for performing time delay operation on input distortion data;

and the subtraction module is connected with the combination module and the delay module and is used for carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

7. An apparatus for implementing signal EVM correction based on time-domain waveform error negative feedback, the apparatus comprising:

a processor configured to execute computer-executable instructions;

a memory storing one or more computer-executable instructions that, when executed by the processor, perform the steps of the method of performing signal EVM correction based on time-domain waveform error negative feedback of any of claims 1 to 5.

8. A processor for implementing signal EVM correction based on time-domain waveform error negative feedback, wherein the processor is configured to execute computer-executable instructions which, when executed by the processor, implement the steps of the method for implementing signal EVM correction based on time-domain waveform error negative feedback as claimed in any one of claims 1 to 5.

9. A computer-readable storage medium, having stored thereon a computer program executable by a processor to perform the steps of the method of performing signal EVM correction based on time-domain waveform error negative feedback of any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of instruments and meters, in particular to the field of wireless communication equipment testing, and specifically relates to a method, a system, a device, a processor and a computer readable storage medium for realizing signal EVM correction based on time domain waveform error negative feedback.

Background

In the field of wireless communication equipment testing, a signal receiver is required to collect signals for analysis, or a signal transmitter is required to be used as a signal source to send out signals, and due to the defects of hardware circuits of the signal transmitter or the signal receiver, the signals are often distorted. Especially, as the technology develops, the bandwidth of the signal becomes larger and the performance requirement of the hardware circuit becomes higher, and the method is provided for compensating the distortion of the signal caused by the receiver or the transmitter circuit of the instrument.

The orthogonal modulation symbols used in wireless communication are generally divided into two components, a real component (denoted as I) and an imaginary component (denoted as Q), and the symbols are plotted on orthogonal coordinates with 1 component as an abscissa and the Q component as an ordinate, so as to obtain a constellation diagram. The constellation diagram can reflect the quality of the signal and the severity of the signal distortion. Fig. 1 and 2 are constellation diagrams of QPSK modulation, and under the condition of good signal quality and small distortion, each data point on the constellation diagram is concentrated near 4 reference points and distributed more densely, as shown in fig. 1. When the signal quality is poor and the distortion is severe, the positions of the data points around the reference point are relatively scattered, as shown in fig. 2. We can judge whether the signal quality is good or bad by analyzing the compactness of the point, and usually use Error Vector Magnitude (EVM) to represent the Vector difference between the actual signal and the reference point. The EVM measures important parameters of the modulated signal quality, including both the amplitude error and the phase error of the signal.

The purpose of compensating for signal distortion is to improve the EVM index. For a receiver, a signal passes through a radio frequency circuit, is converted into a digital signal by an ADC, and finally enters a baseband FPGA, and the distortion of the radio frequency and the ADC is compensated by the FPGA or upper computer software. For a transmitter, a digital signal is generated by an FPGA, sent to a DAC and converted into an analog signal, and finally transmitted by a radio frequency circuit.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method, a system, a device, a processor and a computer-readable storage medium for realizing signal EVM correction based on time-domain waveform error negative feedback, which have the advantages of small error, high precision and wide application range.

In order to achieve the above object, the method, system, apparatus, processor and computer readable storage medium for implementing signal EVM correction based on time domain waveform error negative feedback of the present invention are as follows:

the system for realizing signal EVM correction based on time domain waveform error negative feedback is mainly characterized by comprising the following steps:

(1) obtaining an error waveform through the expected waveform and the original distorted waveform;

(2) training a filter coefficient through a distortion waveform and an error waveform to obtain a coefficient which enables the output of the filter to approach the error waveform;

(3) and correcting and compensating the distortion signal through the coefficient.

Preferably, the step (1) specifically comprises the following steps:

(1.1) acquiring a distorted signal time domain waveform;

(1.2) calculating to obtain expected waveforms with consistent phases according to the modulation types;

and (1.3) subtracting the original distorted signal waveform from the expected waveform to obtain an error waveform.

Preferably, the step (2) specifically comprises the following steps:

(2.1) outputting the distortion waveform as an input sequence and the error waveform as a target;

and (2.2) obtaining a coefficient which enables the output of the filter to approach an error waveform through continuous iterative training.

Preferably, the step (3) specifically includes the following steps:

(3.1) carrying out parallelization processing on the distortion data, and dividing the parallelization data into multiple paths;

(3.2) carrying out convolution operation on the multi-channel parallelization data and the trained filter coefficient;

(3.3) carrying out parallelization combination on the calculated data to obtain an error waveform corresponding to the input end distortion waveform;

(3.4) carrying out time delay operation on the input distortion data;

and (3.5) carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

Preferably, the filter coefficient obtained in step (2) is specifically:

the filter coefficients are obtained according to the following formula:

Δw_n＝e×conj(x_n)；

where e is the difference between the desired output and the actual output, x_nTo input data, w_nAre the filter coefficients.

The system for realizing signal EVM correction based on time domain waveform error negative feedback is mainly characterized by comprising the following components:

the parallelization module is used for performing parallelization processing on the distortion data and dividing the parallelization data into multiple paths of parallelization data;

the operation unit group comprises a plurality of operation units which are connected with the parallelization module, and each operation unit receives one path of parallelization data output by the parallelization module and performs convolution operation with the trained filter coefficient;

the merging module is connected with the operation unit group and used for carrying out parallel merging on the operated data to obtain an error waveform corresponding to the input end distortion waveform;

the time delay module is connected with the parallelization module and is used for performing time delay operation on input distortion data;

and the subtraction module is connected with the combination module and the delay module and is used for carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

The device for realizing signal EVM correction based on time domain waveform error negative feedback is mainly characterized by comprising the following components:

a processor configured to execute computer-executable instructions;

and a memory storing one or more computer-executable instructions that, when executed by the processor, perform the steps of the above-described method for performing signal EVM correction based on time-domain waveform error negative feedback.

The processor for realizing signal EVM correction based on time domain waveform error negative feedback is mainly characterized in that the processor is configured to execute computer executable instructions, and when the computer executable instructions are executed by the processor, the steps of the method for realizing signal EVM correction based on time domain waveform error negative feedback are realized.

The computer-readable storage medium is mainly characterized by having a computer program stored thereon, wherein the computer program is executable by a processor to implement the steps of the method for implementing signal EVM correction based on time-domain waveform error negative feedback.

The method, the system, the device, the processor and the computer readable storage medium for realizing the signal EVM correction based on the time domain waveform error negative feedback can quickly correct the signal distortion brought by a hardware circuit, have good real-time performance, can meet the requirement of high processing rate under the condition of large bandwidth, have large processing bandwidth, are suitable for both a receiver and a transmitter, and have wide application range.

Drawings

Fig. 1 is a schematic diagram of an example QPSK constellation diagram with better signal quality in the prior art.

Fig. 2 is a diagram illustrating an example of a QPSK constellation with poor signal quality in the prior art.

Fig. 3 is a schematic diagram of a real component of a QPSK time-domain waveform of the method for implementing signal EVM correction based on time-domain waveform error negative feedback according to the present invention.

Fig. 4 is a schematic diagram of imaginary components of a QPSK time-domain waveform of the method for implementing signal EVM correction based on time-domain waveform error negative feedback according to the present invention.

Fig. 5 is a schematic diagram of a logic structure of signal correction in the method for implementing signal EVM correction based on time-domain waveform error negative feedback according to the present invention.

Fig. 6 is a schematic diagram of the correction effect of the QPSK signal in the method for implementing signal EVM correction based on time-domain waveform error negative feedback according to the present invention.

Fig. 7 is a diagram illustrating the original effect of an uncorrected distorted QPSK signal.

Detailed Description

In order to more clearly describe the technical contents of the present invention, the following further description is given in conjunction with specific embodiments.

The invention discloses a method for realizing signal EVM correction based on time domain waveform error negative feedback, which comprises the following steps:

(1) obtaining an error waveform through the expected waveform and the original distorted waveform;

(1.1) acquiring a distorted signal time domain waveform;

(1.2) calculating to obtain expected waveforms with consistent phases according to the modulation types;

(1.3) subtracting the original distorted signal waveform from the expected waveform to obtain an error waveform;

(2) training a filter coefficient through a distortion waveform and an error waveform to obtain a coefficient which enables the output of the filter to approach the error waveform;

(2.1) outputting the distortion waveform as an input sequence and the error waveform as a target;

(2.2) obtaining a coefficient which enables the output of the filter to approach an error waveform through continuous iterative training;

(3) correcting and compensating the distortion signal through the coefficient;

(3.1) carrying out parallelization processing on the distortion data, and dividing the parallelization data into multiple paths;

(3.2) carrying out convolution operation on the multi-channel parallelization data and the trained filter coefficient;

(3.3) carrying out parallelization combination on the calculated data to obtain an error waveform corresponding to the input end distortion waveform;

(3.4) carrying out time delay operation on the input distortion data;

and (3.5) carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

As a preferred embodiment of the present invention, the filter coefficients obtained in step (2) specifically include:

the filter coefficients are obtained according to the following formula:

Δw_n＝e×conj(x_n)；

where e is the difference between the desired output and the actual output, x_nTo input data, w_nAre the filter coefficients.

The invention discloses a system for realizing signal EVM correction based on time domain waveform error negative feedback, which comprises:

the parallelization module is used for performing parallelization processing on the distortion data and dividing the parallelization data into multiple paths of parallelization data;

the operation unit group comprises a plurality of operation units which are connected with the parallelization module, and each operation unit receives one path of parallelization data output by the parallelization module and performs convolution operation with the trained filter coefficient;

the merging module is connected with the operation unit group and used for carrying out parallel merging on the operated data to obtain an error waveform corresponding to the input end distortion waveform;

the time delay module is connected with the parallelization module and is used for performing time delay operation on input distortion data;

and the subtraction module is connected with the combination module and the delay module and is used for carrying out subtraction operation on the distorted data and the error waveform to obtain undistorted data.

As a preferred embodiment of the present invention, the apparatus for implementing signal EVM correction based on time-domain waveform error negative feedback includes:

a processor configured to execute computer-executable instructions;

and a memory storing one or more computer-executable instructions that, when executed by the processor, perform the steps of the above-described method for performing signal EVM correction based on time-domain waveform error negative feedback.

As a preferred embodiment of the present invention, the processor for implementing signal EVM correction based on time-domain waveform error negative feedback is configured to execute computer-executable instructions, and when the computer-executable instructions are executed by the processor, the steps of the method for implementing signal EVM correction based on time-domain waveform error negative feedback are implemented.

As a preferred embodiment of the present invention, the computer readable storage medium has stored thereon a computer program executable by a processor to perform the steps of the above-described method for implementing signal EVM correction based on time-domain waveform error negative feedback.

In the specific implementation mode of the invention, the signal distortion brought by a hardware circuit is corrected and compensated, and the vector performance of an instrument receiver or a transmitter is improved.

The invention provides an equalizer structure which can be realized in FPGA and a training mode of equalizer coefficients, which can realize the correction of distortion vector signals and compensate the signal quality deterioration caused by hardware circuit defects.

The filter structure is optimized on the basis of the traditional FIR filter: firstly, a parallelization structure is introduced, so that the structure can process signals with high speed and large bandwidth; secondly, the structure only outputs the error waveform of the signal, and the subtraction operation is carried out between the error waveform and the original signal at the tail of the structure, so that the method is suitable for the correction of a receiver and the correction of a transmitter.

Firstly, a distorted signal time domain waveform is required to be collected, the signal type is usually an orthogonal modulation signal, such as QPSK, 16QAM and the like, then, according to the modulation type, a corresponding (identical phase and known code element) ideal signal time domain waveform is calculated, and an original distorted signal waveform is subtracted from the ideal signal waveform to obtain an error waveform. Fig. 3 and 4 show conventional QPSK time domain waveform diagrams, where fig. 3 is a real part I and fig. 4 is an imaginary part Q. The solid line is the distorted original data, the dotted line is the estimated ideal data with the distortion removed, and the dotted line is the subtracted error waveform.

The filter coefficients are trained by using the distortion waveform and the error waveform, and the training algorithm is realized based on a complex error negative feedback algorithm. The distorted waveform is used as an input sequence, the error waveform is used as a target output of training, and through continuous iterative training, a proper coefficient is found to enable the output of the filter to approach the error waveform corresponding to the input of the filter.

Assuming that the input data is X ═ { X1, X2, X3, … …, xn }, the output data is o, and the filter coefficients are W ═ { W1, W2, W3, … …, wn }, then the output o:

assuming that the desired output of the filter is t, the difference between the desired and actual outputs is e-t-o;

new input data X is continuously used to calculate new difference e, and e is used to repeatedly modify filter coefficient W until e converges to a desired magnitude. Updating W for each training:

w′_n＝w_n+αΔw_n

where α is the learning rate, which determines how fast the coefficient converges during training, Δ w_nAnd calculating according to the e:

Δw_n＝e×conj(x_n)；

thus, by continuously updating the coefficient W, training of the filter is realized.

After training is finished, the needed filter coefficient is obtained, and the coefficient is loaded into a logic module for signal correction, so that correction and compensation of the distortion signal can be realized. The signal correction logic structure diagram is shown in fig. 5.

Firstly, the distortion data caused by hardware is subjected to parallelization processing, can be divided into any multiple paths of parallelization data, and can support input data with higher speed and higher bandwidth. For example, as shown in fig. 5, the data is divided into 3 paths, and when the logical operation speed is 200MHz, the data rate of 600MHz can be processed. And respectively inputting the parallelized data into an operation unit based on an FIR structure, and performing convolution operation on the parallelized data and the trained filter coefficients. And carrying out parallelization combination on the data after the operation is finished, wherein the data is an error waveform corresponding to the distorted waveform of the input end according to the previous training method. And after delaying the input distorted data, performing subtraction operation on the input distorted data and the error waveform obtained after convolution operation, and recovering undistorted data after subtracting an error component from the distorted data.

Fig. 1 of the present invention is an example of a constellation diagram, a QPSK constellation diagram with better signal quality and dense data point distribution. Fig. 2 is an example of a constellation, a QPSK constellation with poor signal quality, with scattered data points. Fig. 3 is a QPSK time domain waveform, the real component. The solid line is the distorted original data, the dotted line is the estimated ideal data with the distortion removed, and the dotted line is the subtracted error waveform. Fig. 4 is a QPSK time domain waveform, the imaginary component. The solid line is the distorted original data, the dotted line is the estimated ideal data with the distortion removed, and the dotted line is the subtracted error waveform. Fig. 5 is a logic structure of signal correction, which is implemented based on FPGA, and is implemented by dividing a signal into parallel multiple paths, performing distortion correction on each path by an FIR structure filter, merging parallel data after correction is completed, and subtracting original data to obtain correction data.

Fig. 6 shows the corrected constellation diagram of the data, and fig. 7 shows the uncorrected constellation diagram, so that after the trained filter coefficients are brought, the filter rejects the signal distortion, and the quality of the output signal is improved.

For a specific implementation of this embodiment, reference may be made to the relevant description in the above embodiments, which is not described herein again.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.

It should be noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by suitable instruction execution devices. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware that is related to instructions of a program, and the program may be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a separate product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The method, the system, the device, the processor and the computer readable storage medium for realizing the signal EVM correction based on the time domain waveform error negative feedback can quickly correct the signal distortion brought by a hardware circuit, have good real-time performance, can meet the requirement of high processing rate under the condition of large bandwidth, have large processing bandwidth, are suitable for both a receiver and a transmitter, and have wide application range.

In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.