IQ imbalance adaptive correction method based on 16QAM signal

Abstract

The present invention provides an IQ imbalance adaptive correction method based on 16QAM signal, which belongs to the field of communication transmission technology. The method comprises: a modulation end signal is input to a demodulation end after IQ imbalance compensation at the modulation end; the demodulation end estimates and compensates the IQ imbalance at the modulation end signal after IQ imbalance compensation at the modulation end to obtain an IQ imbalance compensation signal at the demodulation end; the demodulation end estimates the IQ imbalance compensation coefficient at the modulation end for the demodulation end IQ imbalance compensation signal to obtain the compensation coefficient at the modulation end; the modulation end IQ imbalance compensation is feedback-adjusted by using the compensation coefficient at the modulation end until the compensation coefficient at the modulation end converges, and then the demodulation end IQ imbalance compensation signal is output, so that the IQ imbalance compensation at the modulation end and the demodulation end can be effectively realized even in the presence of Doppler.

Description

Technical Field

[0001] The present invention relates to the field of communication transmission technology, and in particular to an IQ imbalance adaptive correction method based on a 16QAM signal. Background Art

[0002] In high-speed laser communications, signal receivers usually use superheterodyne receivers and zero intermediate frequency receivers. The superheterodyne receiver structure is the most mature receiver structure, and it can achieve excellent performance after careful design. However, due to the overly complex hardware circuit itself and the need for an off-chip bandpass filter with good performance, it has the disadvantages of high device cost, large size and power consumption, and low integration, which seriously restricts its development and application. The transmitter of the zero intermediate frequency receiver structure directly up-converts the baseband signal to obtain the RF signal, and the receiver directly down-converts the RF signal to the baseband signal. The zero intermediate frequency receiver removes the intermediate frequency, has a simple circuit structure, is easy to integrate, and has low cost and power consumption. It has received extremely extensive attention and research in recent years. However, the zero intermediate frequency receiver also has some inherent defects, such as the IQ imbalance problem caused by inconsistent device and circuit characteristics, which affects the performance of the receiver.

[0003] IQ imbalance means that due to the non-ideality of analog devices, the I and Q signals of the zero-IF receiver cannot guarantee 90° complete orthogonality during down-conversion; in addition, the I and Q low-pass filters, analog-to-digital and digital-to-analog converters at the modulation and demodulation ends are not completely consistent, the amplitude gain is different, and the up and down conversion operations will all lead to IQ imbalance. IQ imbalance causes image interference signals, which seriously affects system performance. In particular, for high-speed communication systems, due to the high frequency band, the frequency of the local oscillator signal used in the modulation and demodulation process of the I and Q signals is also very high, so the amplitude and phase of the two signals are more difficult to match than low-frequency communication systems. In summary, it is very important and meaningful to study the compensation algorithm for IQ imbalance.

[0004] The methods of suppressing IQ imbalance are mainly divided into using high-performance analog devices and estimating and compensating in the digital domain. Although the former can suppress its influence from the source, it is difficult to completely and efficiently eliminate IQ imbalance due to the large size and high cost of analog devices. The latter can be compensated by digital signal processing methods, which has the advantages of low cost, continuous improvement, and stronger adaptability to the environment than using analog devices.

[0005] At present, the commonly used methods for IQ imbalance compensation using digital signal processing technology mainly include GSOP (Gram-Schmidt orthogonalization) algorithm, BASS (blind source signal separation) algorithm and IQ imbalance compensation algorithm based on training sequence. Among them, GSOP algorithm is the earliest proposed time domain compensation method that can realize IQ imbalance correction, but its compensation accuracy is not as good as BASS algorithm, and the implementation process involves division operation, which is difficult to implement. BASS compensation accuracy is high, but it is mainly applicable to QPSK signals, and the compensation effect for modulation modes such as 16QAM is poor. The training sequence compensation algorithm requires the additional transmission of specially designed preamble training sequences, resulting in low bandwidth utilization, and after the system communication protocol is changed, the training sequence needs to be redesigned, and the self-adaptability is relatively poor.

[0006] Therefore, how to achieve adaptive correction of IQ imbalance of 16QAM signals has become a technical problem that those skilled in the art need to solve urgently. Summary of the invention

[0007] The present invention provides an IQ imbalance adaptive correction method based on 16QAM signal, which is used to solve the defect that the IQ imbalance adaptive correction of 16QAM signal cannot be performed in the prior art.

[0008] In a first aspect, the present invention provides an IQ imbalance adaptive correction method based on a 16QAM signal, comprising:

[0009] The modulation end signal is input to the demodulation end after IQ imbalance compensation at the modulation end;

[0010] The demodulation end performs demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation to obtain a demodulation end IQ imbalance compensation signal;

[0011] The demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient;

[0012] The modulation-end IQ imbalance compensation is feedback-adjusted by using the modulation-end compensation coefficient until the modulation-end compensation coefficient converges, and then the demodulation-end IQ imbalance compensation signal is output.

[0013] According to a method for adaptively correcting IQ imbalance based on 16QAM signals provided by the present invention, the method for estimating and compensating IQ imbalance at the demodulation end includes:

[0014] Performing array reading on the modulation end signal after the modulation end IQ imbalance compensation to obtain multi-channel parallel array signals;

[0015] Demodulation-end IQ imbalance correction is performed on the multi-path parallel array signals respectively to obtain a demodulation-end IQ imbalance compensation signal.

[0016] According to a method for adaptively correcting IQ imbalance based on 16QAM signals provided by the present invention, after respectively performing demodulation end IQ imbalance correction on the multi-channel parallel array signals, the method further comprises:

[0017] Generate a random number M between 1 and N through the random number generation submodule;

[0018] Selecting, by a data selection submodule, a demodulation end compensated output signal corresponding to the random number M from the data after the demodulation end IQ imbalance correction is performed;

[0019] Inputting the compensated output signal of the demodulation end corresponding to the random number M into the error extraction submodule to obtain an error;

[0020] Inputting the error into a compensation coefficient updating module to update the compensation coefficient;

[0021] The compensation coefficients are used to perform feedback adjustment on the IQ imbalance correction of the demodulation end of the multi-path parallel array signals.

[0022] According to an IQ imbalance adaptive correction method based on 16QAM signal provided by the present invention, the error extraction submodule is:

[0023]

[0024] in, Indicates the error, It represents the compensated output signal of the demodulation end corresponding to the random number M, and A, B and C are determined based on the position characteristics of the 16QAM signal.

[0025] According to a 16QAM signal-based IQ imbalance adaptive correction method provided by the present invention, the demodulation end IQ imbalance correction is performed on the multi-path parallel array signals respectively, comprising:

[0026]

[0027] in, is the i-th input signal before compensation at time k, is the i-th output signal after compensation at time k, and is the compensation coefficient at time k, express The conjugation of.

[0028] According to an IQ imbalance adaptive correction method based on 16QAM signal provided by the present invention, the updated compensation coefficient is:

[0029]

[0030] in, , , is the iteration step length, express k Moment n The compensation coefficient, express k Moment m The conjugate of the compensation coefficient, express The square of .

[0031] According to the present invention, an IQ imbalance adaptive correction method based on a 16QAM signal also includes:

[0032] First, the IQ imbalance compensation coefficient of the modulation end is estimated, and the IQ imbalance compensation module of the modulation end is turned off;

[0033] When the modulation end IQ imbalance compensation coefficient estimation converges, the obtained compensation coefficient is fed back to the modulation end IQ imbalance compensation module, and the modulation end IQ imbalance compensation is performed, and the modulation end IQ imbalance compensation coefficient estimation module is closed.

[0034] According to the present invention, an IQ imbalance adaptive correction method based on a 16QAM signal also includes:

[0035] The modulation end performs modulation preprocessing, carrier modulation and digital-to-analog conversion on the modulation signal;

[0036] The demodulation end performs analog-to-digital conversion, demodulation preprocessing, timing synchronization, matching filtering, channel equalization and carrier synchronization on the input signal of the modulation end.

[0037] In a second aspect, the present invention further provides an IQ imbalance adaptive correction device based on a 16QAM signal, comprising:

[0038] A modulation module, used for inputting the modulation end signal into the demodulation end after IQ imbalance compensation at the modulation end;

[0039] The demodulation module is used for the demodulation end to estimate and compensate for the IQ imbalance of the modulation end signal after the IQ imbalance compensation of the modulation end, so as to obtain the IQ imbalance compensation signal of the demodulation end; the demodulation end estimates the IQ imbalance compensation coefficient of the modulation end on the IQ imbalance compensation signal of the demodulation end, so as to obtain the compensation coefficient of the modulation end;

[0040] The feedback module is used to perform feedback adjustment on the modulation end IQ imbalance compensation by using the modulation end compensation coefficient until the modulation end compensation coefficient converges, and then output the demodulation end IQ imbalance compensation signal.

[0041] In a third aspect, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, an IQ imbalance adaptive correction method based on a 16QAM signal as described in any one of the above is implemented.

[0042] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described methods for adaptively correcting IQ imbalance based on 16QAM signals.

[0043] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any of the above-mentioned methods for adaptively correcting IQ imbalance based on 16QAM signals.

[0044] The IQ imbalance adaptive correction method based on 16QAM signal provided by the present invention comprises: inputting the modulation end signal into the demodulation end after the modulation end IQ imbalance compensation; the demodulation end performs demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation to obtain the demodulation end IQ imbalance compensation signal; the demodulation end performs modulation end IQ imbalance compensation coefficient estimation on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; and the modulation end IQ imbalance compensation is feedback-adjusted by using the modulation end compensation coefficient until the modulation end compensation coefficient converges, and then the demodulation end IQ imbalance compensation signal is output. Through the demodulation end IQ imbalance compensation, channel interference and Doppler do not affect the demodulation end IQ imbalance coefficient estimation, and first compensating the demodulation end IQ imbalance helps to improve the timing synchronization accuracy in conventional demodulation. The modulation end IQ imbalance compensation coefficient estimation is performed after the conventional demodulation at the demodulation end, avoiding the influence of channel interference and Doppler on the modulation end IQ imbalance compensation coefficient estimation. Even in the presence of Doppler, IQ imbalance compensation can be effectively achieved at the modulation and demodulation ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 It is a schematic diagram of the influence of IQ phase imbalance and IQ amplitude imbalance on constellation points in the prior art;

[0047] Figure 2 16QAM signal-based IQ imbalance adaptive correction method provided in this embodiment;

[0048] Figure 3 1 is a flow chart of an IQ imbalance adaptive correction method based on a 16QAM signal provided in this embodiment;

[0049] Figure 4 2 is a schematic diagram showing the principle of IQ imbalance estimation and compensation at the demodulation end provided by this embodiment;

[0050] Figure 5 It is a comparison constellation diagram before and after compensation obtained by the method of the present invention;

[0051] Figure 6 is a schematic diagram for comparing the performance of different algorithms provided in this embodiment;

[0052] Figure 7 is a schematic diagram of estimating the IQ imbalance compensation coefficient at the modulation end provided by this embodiment;

[0053] Figure 8 is a schematic diagram of a modulation end IQ imbalance compensation module provided in this embodiment;

[0054] Fig. 9 is a constellation diagram before and after IQ imbalance compensation from the modulation end provided by this embodiment;

[0055] Fig.10 This is a performance diagram of compensating for IQ imbalance of a 16QAM signal modulation end at a modulation end and a demodulation end provided by this embodiment;

[0056] Fig.11 1 is a schematic diagram of bit error rate performance for compensating for IQ imbalance at the modulation end and the demodulation end provided by this embodiment;

[0057] Fig.12 1 is a schematic diagram of the structure of an IQ imbalance adaptive correction device based on a 16QAM signal provided in this embodiment;

[0058] Fig.13 It is a schematic diagram of the structure of the electronic device provided in this embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In a zero-IF receiver, the IQ modulator and the 90-degree optical mixer at the demodulation end are equivalent to an orthogonal coordinate system, that is, the two outputs differ in phase. Due to manufacturing defects of both, the received signals lose orthogonality, i.e. IQ imbalance. The damage model of IQ imbalance can be expressed by the following formula (1):

[0061] (1)

[0062] in, and Represents amplitude imbalance, Represents phase imbalance, and represents the original signal, and Indicates the signal after being affected by IQ imbalance. Figure 1 As shown in Figure 1, the impact of IQ phase imbalance and IQ amplitude imbalance on constellation points when noise exists. Figure 1 Through various situations, we can clearly understand the impact of IQ phase imbalance and IQ amplitude imbalance on the constellation points respectively and their joint impact on the constellation points. It can be seen that IQ imbalance interference causes the distribution of constellation points to no longer be near the symbol standard point, and the Euclidean distance between the constellation point and other symbols becomes smaller, which obviously affects the demodulation bit error rate.

[0063] Figure 2 is a structural principle diagram of an IQ imbalance adaptive correction method based on 16QAM signal provided in this embodiment, Figure 3 It is a flowchart of the IQ imbalance adaptive correction method based on 16QAM signal provided in this embodiment.

[0064] like Figure 2 As shown in the figure, the modulation end is composed of modulation preprocessing (including coding and mapping), IQ imbalance compensation at the modulation end, carrier modulation, and DAC (digital-to-analog conversion) modules. The modulation end signal reaches the demodulation end through the channel. The demodulation end is composed of ADC (analog-to-digital conversion), demodulation preprocessing (including extraction filtering, AGC automatic gain control), demodulation end IQ imbalance estimation & compensation, conventional demodulation (including timing synchronization, matched filtering, channel equalization and carrier synchronization), and modulation end IQ imbalance compensation coefficient estimation module.

[0065] like Figure 3 As shown, the IQ imbalance adaptive correction method based on 16QAM signal provided in the embodiment of the present invention mainly includes the following steps:

[0066] 101. The modulation end signal is input to the demodulation end after IQ imbalance compensation at the modulation end.

[0067] In a specific implementation process, the signal flows from the modulation end to the demodulation end and then outputs the signal. The workflow of the modulation end is to first undergo modulation preprocessing, then perform modulation end IQ imbalance compensation, then perform carrier modulation and digital-to-analog conversion, and send the signal to the demodulation end through the channel.

[0068] The coefficient of the modulation end IQ imbalance compensation at the modulation end is controlled by the estimation of the modulation end IQ imbalance compensation coefficient at the demodulation end, thereby forming a feedback adjustment. Performing the modulation end IQ imbalance compensation at the modulation end instead of the demodulation end will not destroy the structure of the white noise and will not affect the bit error rate.

[0069] 102. The demodulation end estimates and compensates for the IQ imbalance of the modulation end signal after the IQ imbalance compensation of the modulation end, and obtains a demodulation end IQ imbalance compensated signal.

[0070] The demodulation end IQ imbalance estimation and compensation are performed through the demodulation end. Figure 4 FIG. 2 is a schematic diagram showing the principle of IQ imbalance estimation and compensation at the demodulation end provided by this embodiment. Figure 4 As shown, the whole is divided into the first part of parallel processing (including array reading, N-way IQ imbalance correction, array combination) and the second part of serial processing (including random number generation, data selection, error extraction, compensation coefficient update). The first part performs IQ imbalance compensation at the demodulation end, and the second part performs IQ imbalance compensation coefficient calculation at the demodulation end. Through such a structure, parallel processing of IQ imbalance compensation is realized, and the IQ imbalance compensation signal at the demodulation end is obtained.

[0071] 103. The demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient.

[0072] After obtaining the demodulation end IQ imbalance compensation signal, the demodulation end is further used to estimate the modulation end IQ imbalance compensation coefficient for the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient, that is, the modulation end compensation coefficient is determined at the demodulation end.

[0073] Before conventional demodulation at the demodulation end, IQ imbalance compensation at the demodulation end is performed. On the one hand, channel interference and Doppler do not affect the estimation of the IQ imbalance coefficient at the demodulation end, so there is no need to compensate for the channel and Doppler through channel equalization and carrier synchronization in conventional demodulation. On the other hand, compensating the IQ imbalance at the demodulation end first helps improve the timing synchronization accuracy in conventional demodulation. After conventional demodulation at the demodulation end, the IQ imbalance compensation coefficient estimation at the modulation end is performed, which avoids the influence of channel interference and Doppler on the estimation of the IQ imbalance compensation coefficient at the modulation end.

[0074] 104. Perform feedback adjustment on the modulation end IQ imbalance compensation by using the modulation end compensation coefficient until the modulation end compensation coefficient converges, and then output a demodulation end IQ imbalance compensation signal.

[0075] Since the modulation end IQ imbalance time-varying is very small, the modulation end IQ imbalance compensation module and the modulation end IQ imbalance compensation coefficient estimation module are controlled according to the following process: first, the modulation end IQ imbalance compensation coefficient is estimated, and the modulation end IQ imbalance compensation module is turned off at the same time; when the modulation end IQ imbalance compensation coefficient estimation converges, the obtained compensation coefficient is fed back to the modulation end IQ imbalance compensation module, and the modulation end IQ imbalance compensation is performed, and the modulation end IQ imbalance compensation coefficient estimation module is turned off.

[0076] like Figure 4 As shown, the demodulation end IQ imbalance estimation and compensation in this embodiment includes: performing array reading on the modulation end signal after the modulation end IQ imbalance compensation to obtain multiple parallel array signals; performing demodulation end IQ imbalance correction on the multiple parallel array signals respectively to obtain the demodulation end IQ imbalance compensation signal.

[0077] Specifically, when receiving and processing high-speed or ultra-high-speed signals, parallel processing is usually used, that is, multiple outputs are calculated in the same clock cycle. At time k, the input signal of the N-way parallel module before compensation is (2):

[0078] (2)

[0079] in, Represents the i-th parallel input IQ signal at time k.

[0080] In the first part of the demodulation end IQ imbalance estimation and compensation module, the array reading submodule is first used to obtain the parallel input signal Read out Then The 1st, 2nd, ..., Nth parallel IQ imbalance correction submodules are input respectively. The i-th parallel IQ imbalance correction submodule performs IQ imbalance correction according to the correction formula (3), as follows:

[0081] (3)

[0082] in, is the i-th input signal before compensation at time k, is the i-th output signal after compensation at time k, and is the compensation coefficient at time k, express The conjugation of.

[0083] Finally, At the same time, the array combination submodule is input to obtain the compensation output signal of the demodulation end IQ imbalance compensation signal at time k, as shown in formula (4): (4)

[0084] like Figure 4 As shown, after the demodulation end IQ imbalance compensation is completed by the first part, the demodulation end IQ imbalance compensation coefficient is calculated by the second part.

[0085] Specifically, after the demodulation end IQ imbalance correction is performed on the multi-channel parallel array signals, a random number M between 1 and N is generated by the random number generation submodule; The demodulation end output signal after compensation corresponding to the random number M is selected from the random number M, that is, the data of the Mth channel ;Will Input the error extraction submodule to get the error.

[0086] The error extraction submodule is (5):

[0087] (5)

[0088] in, Indicates the error, It represents the compensated output signal of the demodulation end corresponding to the random number M, and A, B and C are determined based on the position characteristics of the 16QAM signal.

[0089] The advantage of using formula (5) to calculate the error is that the steady-state error of the 16QAM signal is 0, so there is good compensation accuracy.

[0090] Finally, the input error To the compensation coefficient update module, the compensation coefficient is updated by formula (6); the compensation coefficient is used to perform feedback adjustment on the IQ imbalance correction of the demodulation end of the multi-channel parallel array signal.

[0091] (6)

[0092] in, , , is the iteration step length, express k Moment n The compensation coefficient, express k Moment m The conjugate of the compensation coefficient, express The square of .

[0093] By dividing the IQ imbalance estimation and compensation at the demodulation end into two parts, the first part is processed in parallel and the second part is processed in series, a lot of computing resources are saved compared to the full parallel processing method. The reliability of error extraction is improved by selecting a signal with random numbers instead of a fixed signal for error extraction. Figure 5 This is a comparison of the constellation diagrams before and after compensation obtained by the method of the present invention. It can be seen that the IQ imbalance at the demodulation end ( and They are 1.08 and 0.91 respectively. It can be seen from the constellation diagrams before and after compensation that the present invention can effectively compensate for the influence of IQ imbalance at the demodulation end, so that the signal mapping point is located near the standard position again.

[0094] Figure 6 4 is a schematic diagram for comparing the performance of different algorithms provided in this embodiment.

[0095] like Figure 6 As shown, in order to compare the performance of the correction method of the present invention with the BASS algorithm and the GSOP algorithm in compensating the IQ imbalance of the demodulation end of the 16QAM signal, the three methods are used to correct the same IQ imbalance of the demodulation end ( and They are 1.08 and 0.91 respectively. It can be seen that the compensation effect of the method adopted by the present invention is the best, which is better than the GSOP algorithm and the BASS algorithm. The performance superiority of the present invention is verified by the simulation results.

[0096] Figure 7 It is a schematic diagram of estimating the IQ imbalance compensation coefficient at the modulation end provided by this embodiment.

[0097] like Figure 7 As shown, based on the above embodiment, by Figure 7It can be seen that the overall structure of the IQ imbalance compensation coefficient estimation at the demodulation end is very similar to the IQ imbalance estimation and compensation module structure at the demodulation end. The difference is that the first part does not combine the outputs of the 1st, 2nd, ..., N-way parallel IQ imbalance correction submodules through the data combination submodule as the module output, but directly passes the module input as the module output. And the coefficients calculated in the second part and After convergence, the coefficients are recorded by the coefficient storage submodule and used to set the modulation end IQ imbalance compensation module.

[0098] Figure 8 It is a schematic diagram of the IQ imbalance compensation module at the modulation end provided in this embodiment.

[0099] like Figure 8 As shown, its overall structure is the same as the first part of the demodulation end IQ imbalance estimation and compensation module, the difference is that the compensation coefficient and It is not calculated by the second part, but recorded by the coefficient setting, that is, the IQ imbalance compensation coefficient estimation module at the modulation end. and .

[0100] Furthermore, it should be noted that the reason why the modulation end IQ imbalance compensation module is placed at the modulation end rather than the demodulation end in the present invention is as follows:

[0101] Assume that the IQ imbalance at the modulation end can be expressed by matrix (7):

[0102] (7)

[0103] Then the IQ imbalance compensation process is equivalent to multiplying the matrix The inverse matrix Therefore, the compensation at the demodulation end is equivalent to (8):

[0104] (8)

[0105] in, and Represent the noise of I path and Q path respectively.

[0106] The compensation at the modulation end is equivalent to (9):

[0107] (9)

[0108] It can be seen that although the IQ imbalance of the signal is compensated at the demodulation end, the Gaussian structure of the noise is Destruction; while compensation at the modulation end not only compensates for the signal IQ imbalance, but also does not change the noise structure, thus achieving better demodulation performance.

[0109] Fig. 9 1 is a constellation diagram before and after IQ imbalance compensation from the modulation end provided by this embodiment.

[0110] like Fig. 9 As shown, and They are 1.08 and 0.91 respectively. It is 8°, so it can be obtained that the influence of IQ imbalance at the modulation end on the signal is different from that at the demodulation end, thus increasing the difficulty of compensation; for IQ imbalance at the modulation end, the constellation diagram compensated at the modulation end is better than that at the demodulation end; the influence of IQ imbalance at the modulation end can be effectively compensated.

[0111] Fig.10 It is a performance diagram of compensating for IQ imbalance of a 16QAM signal modulation end at a modulation end and a demodulation end provided by this embodiment.

[0112] like Fig.10 As shown, the same modulation end IQ imbalance is achieved at the modulation end and the demodulation end ( and They are 1.08 and 0.91 respectively. The compensation is performed at the modulation end (8°) and the bit error rate is compared. It can be seen that the compensation effect is better at the modulation end.

[0113] Fig.11 It is a schematic diagram of bit error rate performance of simultaneously compensating for IQ imbalance at the modulation end and the demodulation end provided by this embodiment.

[0114] like Fig.11 As shown in the figure, through simulation analysis, the signal is modulated using 16QAM, and the IQ amplitude imbalance coefficients at the modulation end and the demodulation end are the same: and The IQ phase imbalance coefficients are 1.04 and 0.96 respectively. 4°. Through the simulation of a large number of symbol data (the number of simulation symbols is 1e8), the relationship curve between the bit error rate and signal-to-noise ratio of the signal demodulation when the method is used to compensate for IQ imbalance and when the method is not used to compensate for IQ imbalance is compared with the bit error rate theoretical value curve. It can be seen that after adopting this compensation method, the demodulation bit error rate of the signal is significantly reduced and is very close to the theoretical value; for example, in the bit error rate There is a gain of more than 1.5dB at the bit error rate There is a gain greater than 2dB.

[0115] In summary, the IQ imbalance adaptive correction method based on 16QAM signal of the present invention has the following advantages:

[0116] The present invention reduces the influence of Gaussian white noise by adopting equivalent adaptive iteration, and simulation proves (see Figure 6 , Fig.10 , Fig.11 )The demodulation bit error rate of the present invention at any signal-to-noise ratio is very close to the theoretical value. The present invention ensures the good compensation accuracy of the BASS algorithm, while breaking through the limitation that the BASS algorithm is not applicable to 16QAM signals; compared with the GSOP algorithm, the present invention has better compensation accuracy, and simulation proves (see Figure 6 ) The present invention has superior performance. In view of the problem that Doppler causes the traditional algorithm to be unable to compensate for the IQ imbalance at the modulation end, the present invention also proposes a structure in which the IQ imbalance compensation method applicable to 16QAM signals is used to compensate for the IQ imbalance at the modulation end and the demodulation end respectively.

[0117] High efficiency. The present invention not only provides an IQ imbalance compensation method applicable to 16QAM signals, but also proposes a parallel processing structure of the method, through which IQ imbalance compensation for high-rate and ultra-high-rate signals can be achieved with very little resource cost.

[0118] Easy to implement. The calculation process of the present invention mainly uses multiplication, addition, and modulus operations, while submodules such as random number generation use mature methods in digital signal processing. Therefore, the present invention is very suitable for FPGA (programmable logic controller) development and implementation.

[0119] Adaptive: The present invention estimates IQ imbalance in real time and can adaptively track changes in IQ imbalance.

[0120] Universality. This technical method is applicable to application scenarios such as satellite-to-ground laser communication, intersatellite laser communication, and wireless microwave communication, where high-speed zero intermediate frequency reception is required.

[0121] Based on the same general inventive concept, the present invention also protects an IQ imbalance adaptive correction device based on a 16QAM signal. The IQ imbalance adaptive correction device based on a 16QAM signal provided by the present invention is described below. The IQ imbalance adaptive correction device based on a 16QAM signal described below and the IQ imbalance adaptive correction method based on a 16QAM signal described above can refer to each other.

[0122] Fig.12 It is a structural diagram of an IQ imbalance adaptive correction device based on 16QAM signal provided in this embodiment.

[0123] like Fig.12 As shown, this embodiment provides an IQ imbalance adaptive correction device based on 16QAM signal, including:

[0124] Modulation module 1201, used for inputting the modulation end signal into the demodulation end after the modulation end IQ imbalance compensation;

[0125] The demodulation module 1202 is configured to perform demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation, and obtain the demodulation end IQ imbalance compensation signal; the demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal, and obtain the modulation end compensation coefficient;

[0126] The feedback module 1203 is used to perform feedback adjustment on the modulation end IQ imbalance compensation by using the modulation end compensation coefficient until the modulation end compensation coefficient converges, and then output a demodulation end IQ imbalance compensation signal.

[0127] Furthermore, the demodulation module 1202 in this embodiment is specifically used for:

[0128] Performing array reading on the modulation end signal after the modulation end IQ imbalance compensation to obtain multi-channel parallel array signals;

[0129] Demodulation-end IQ imbalance correction is performed on the multi-path parallel array signals respectively to obtain a demodulation-end IQ imbalance compensation signal.

[0130] Furthermore, the demodulation module 1202 in this embodiment is further configured to:

[0131] Generate a random number M between 1 and N through the random number generation submodule;

[0132] Selecting, by a data selection submodule, a demodulation end compensated output signal corresponding to the random number M from the data after the demodulation end IQ imbalance correction is performed;

[0133] Inputting the compensated output signal of the demodulation end corresponding to the random number M into the error extraction submodule to obtain an error;

[0134] Inputting the error into a compensation coefficient updating module to update the compensation coefficient;

[0135] The compensation coefficients are used to perform feedback adjustment on the IQ imbalance correction of the demodulation end of the multi-path parallel array signals.

[0136] Furthermore, the error extraction submodule in this embodiment is:

[0137]

[0138] in, Indicates the error, It represents the compensated output signal of the demodulation end corresponding to the random number M, and A, B and C are determined based on the position characteristics of the 16QAM signal.

[0139] Furthermore, the demodulation end IQ imbalance correction is performed on the multi-path parallel array signals respectively in this embodiment, including:

[0140]

[0141] in, is the i-th input signal before compensation at time k, is the i-th output signal after compensation at time k, and is the compensation coefficient at time k, express The conjugation of.

[0142] Furthermore, the update compensation coefficient in this embodiment is:

[0143]

[0144] in, , , is the iteration step length, express k Moment n The compensation coefficient, express k Moment m The conjugate of the compensation coefficient, express The square of .

[0145] Furthermore, the IQ imbalance adaptive correction device based on 16QAM signal in this embodiment is also used for:

[0146] First, the IQ imbalance compensation coefficient of the modulation end is estimated, and the IQ imbalance compensation module of the modulation end is turned off;

[0147] When the modulation end IQ imbalance compensation coefficient estimation converges, the obtained compensation coefficient is fed back to the modulation end IQ imbalance compensation module, and the modulation end IQ imbalance compensation is performed, and the modulation end IQ imbalance compensation coefficient estimation module is closed.

[0148] Furthermore, the IQ imbalance adaptive correction device based on 16QAM signal in this embodiment is also used for:

[0149] The modulation end performs modulation preprocessing, carrier modulation and digital-to-analog conversion on the modulation signal;

[0150] The demodulation end performs analog-to-digital conversion, demodulation preprocessing, timing synchronization, matching filtering, channel equalization and carrier synchronization on the input signal of the modulation end.

[0151] Fig.13 It is a schematic diagram of the structure of the electronic device provided in this embodiment.

[0152] like Fig.13 As shown, the electronic device may include: a processor (processor) 1310, a communication interface (Communications Interface) 1320, a memory (memory) 1330 and a communication bus 1340, wherein the processor 1310, the communication interface 1320, and the memory 1330 communicate with each other through the communication bus 1340. The processor 1310 can call the logic instructions in the memory 1330 to execute the IQ imbalance adaptive correction method based on the 16QAM signal, the method comprising: the modulation end signal is input into the demodulation end after the modulation end IQ imbalance compensation; the demodulation end performs demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation to obtain the demodulation end IQ imbalance compensation signal; the demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; the modulation end compensation coefficient is used to feedback adjust the modulation end IQ imbalance compensation until the modulation end compensation coefficient converges, and then the demodulation end IQ imbalance compensation signal is output.

[0153] In addition, the logic instructions in the above-mentioned memory 1330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0154] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the IQ imbalance adaptive correction method based on the 16QAM signal provided by the above methods, and the method includes: the modulation end signal is input into the demodulation end after the modulation end IQ imbalance compensation; the demodulation end estimates and compensates the demodulation end IQ imbalance of the modulation end signal after the modulation end IQ imbalance compensation to obtain the demodulation end IQ imbalance compensation signal; the demodulation end estimates the modulation end IQ imbalance compensation coefficient of the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; and the modulation end compensation coefficient is used to feedback adjust the modulation end IQ imbalance compensation until the modulation end compensation coefficient converges, and then the demodulation end IQ imbalance compensation signal is output.

[0155] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the processor executes the IQ imbalance adaptive correction method based on the 16QAM signal provided by the above-mentioned methods, the method comprising: the modulation end signal is input into the demodulation end after the modulation end IQ imbalance compensation; the demodulation end performs demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation to obtain the demodulation end IQ imbalance compensation signal; the demodulation end performs modulation end IQ imbalance compensation coefficient estimation on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; the modulation end compensation coefficient is used to feedback adjust the modulation end IQ imbalance compensation until the modulation end compensation coefficient converges, and then the demodulation end IQ imbalance compensation signal is output.

[0156] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0157] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adaptively correcting IQ imbalance based on 16QAM signal, characterized in that: include: The modulation end signal is input to the demodulation end after IQ imbalance compensation at the modulation end; The demodulation end performs demodulation end IQ imbalance estimation and compensation on the modulation end signal after the modulation end IQ imbalance compensation to obtain a demodulation end IQ imbalance compensation signal; The demodulation end IQ imbalance estimation and compensation comprises: performing array reading on the modulation end signal after the modulation end IQ imbalance compensation to obtain a multi-channel parallel array signal, and performing demodulation end IQ imbalance correction on the multi-channel parallel array signal respectively to obtain a demodulation end IQ imbalance compensation signal; Generate a random number M between 1 and N through a random number generation submodule, where N represents the number of parallel array signals; select a demodulation end compensated output signal corresponding to the random number M from the data after the demodulation end IQ imbalance correction through a data selection submodule; input the demodulation end compensated output signal corresponding to the random number M into an error extraction submodule to obtain an error; input the error into a compensation coefficient update module to update the compensation coefficient; and use the compensation coefficient to perform feedback adjustment on the demodulation end IQ imbalance correction of the multi-channel parallel array signals respectively; The error extraction submodule is: ； in, Indicates the error, represents the compensated output signal of the demodulation end corresponding to the random number M, where A, B and C are determined based on the position characteristics of the 16QAM signal; The demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; The modulation-end IQ imbalance compensation is feedback-adjusted by using the modulation-end compensation coefficient until the modulation-end compensation coefficient converges, and then the demodulation-end IQ imbalance compensation signal is output.

2. The IQ imbalance adaptive correction method based on 16QAM signal according to claim 1, characterized in that: The demodulation end IQ imbalance correction is performed on the multi-path parallel array signals respectively, including: ； in, is the i-th input signal before compensation at time k, is the i-th output signal after compensation at time k, and is the compensation coefficient at time k, express The conjugation of.

3. The IQ imbalance adaptive correction method based on 16QAM signal according to claim 2, characterized in that: The update compensation coefficient is: ； in, , , is the iteration step length, express k Moment n The compensation coefficient, express k Moment m The conjugate of the compensation coefficient, express The square of .

4. The IQ imbalance adaptive correction method based on 16QAM signal according to any one of claims 1 to 3, characterized in that: Also includes: First, the IQ imbalance compensation coefficient of the modulation end is estimated, and the IQ imbalance compensation module of the modulation end is turned off; When the modulation end IQ imbalance compensation coefficient estimation converges, the obtained compensation coefficient is fed back to the modulation end IQ imbalance compensation module, and the modulation end IQ imbalance compensation is performed, and the modulation end IQ imbalance compensation coefficient estimation module is closed.

5. The IQ imbalance adaptive correction method based on 16QAM signal according to any one of claims 1 to 3, characterized in that: Also includes: The modulation end performs modulation preprocessing, carrier modulation and digital-to-analog conversion on the modulation signal; The demodulation end performs analog-to-digital conversion, demodulation preprocessing, timing synchronization, matching filtering, channel equalization and carrier synchronization on the input signal of the modulation end.

6. An IQ imbalance adaptive correction device based on 16QAM signal, characterized in that: include: A modulation module, used for inputting the modulation end signal into the demodulation end after IQ imbalance compensation at the modulation end; The demodulation module is used for the demodulation end to estimate and compensate the IQ imbalance of the modulation end signal after the IQ imbalance compensation of the modulation end, so as to obtain the IQ imbalance compensation signal of the demodulation end; specifically used for: performing array reading on the modulation end signal after the IQ imbalance compensation of the modulation end, so as to obtain multi-channel parallel array signals, performing demodulation end IQ imbalance correction on the multi-channel parallel array signals respectively, so as to obtain the IQ imbalance compensation signal of the demodulation end; generating a random number M between 1 and N through a random number generation submodule, where N represents the number of parallel array signals; Selecting, by a data selection submodule, a demodulation end compensated output signal corresponding to the random number M from the data after the demodulation end IQ imbalance correction is performed; Input the compensated output signal of the demodulation end corresponding to the random number M into the error extraction submodule to obtain an error; input the error into the compensation coefficient update module to update the compensation coefficient; use the compensation coefficient to perform feedback adjustment on the demodulation end IQ imbalance correction of the multi-channel parallel array signal respectively; The error extraction submodule is: ； in, Indicates the error, The demodulation end compensated output signal corresponding to the random number M is represented, and A, B and C are determined based on the position characteristics of the 16QAM signal; the demodulation end estimates the modulation end IQ imbalance compensation coefficient on the demodulation end IQ imbalance compensation signal to obtain the modulation end compensation coefficient; The feedback module is used to perform feedback adjustment on the modulation end IQ imbalance compensation by using the modulation end compensation coefficient until the modulation end compensation coefficient converges, and then output the demodulation end IQ imbalance compensation signal.

7. 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 program, the IQ imbalance adaptive correction method based on 16QAM signal is implemented as described in any one of claims 1 to 5.

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