Adaptive receiving array intermodulation interference cancellation method and device

Abstract

The invention relates to a self-adaptive receiving array intermodulation interference cancellation method and device, and the method comprises the steps: collecting data from all downlink channels, and collecting data from uplink channels which need to be subjected to interference cancellation; constructing a fitting intermodulation signal by using a downlink signal and a power amplifier intermodulation model, and performing uplink shaping filtering on the fitting intermodulation signal to obtain a fitting intermodulation signal only containing an uplink passband part; performing cross-correlation operation on the filtered fitting intermodulation signal and an uplink actual interference signal, comparing a cross-correlation operation result with a preset threshold, and recording a set of all downlink channels which can interfere uplink reception as B according to a comparison result; an optimization algorithm is used for estimating to obtain a counteracting coefficient of a downlink channel set B and uplink interference, then the counteracting coefficient is combined with a downlink signal to generate a counteracting signal which is equal to the uplink interference in size and opposite to the uplink interference in phase, and finally the generated counteracting signal and the uplink signal are added or subtracted to eliminate interference falling in an uplink band.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna array receiving and transmitting interference removal, and more specifically, to an adaptive receiving array intermodulation interference cancellation method and device. Background Art

[0002] In a coplanar antenna array, when the antenna works in FDD mode, the transmitted signal will generate nonlinear spectra due to the nonlinear characteristics of the transmit channel. These spectra usually fall into the receive frequency band. Even after the transmit and receive antennas are isolated and the transmit out-of-band filter is suppressed, some energy will still remain, thus affecting the signal-to-noise ratio of the receive link.

[0003] Usually, the energy outside the transmission band is suppressed by a filter after the last amplifier stage of the transmission. However, increasing the out-of-band suppression of the filter will lead to a decrease in the gain within the transmission band and a corresponding increase in the size and weight of the filter, thereby affecting the efficiency, power consumption, size and weight of the transmission link.

[0004] In order not to affect the efficiency, power consumption and volume of the transmission link, the present invention provides a method for canceling interference on the received signal without imposing overly stringent requirements on the transmission filter, only requiring a smaller sampling rate to achieve the purpose, reducing algorithm resource pressure. Summary of the invention

[0005] The present invention aims to overcome at least one defect (shortcoming) of the above-mentioned prior art and provide a method and device for adaptive receiving array intermodulation interference cancellation, which effectively solves the out-of-band interference of transmission on reception in the antenna array, greatly reduces the demand of the transmission channel for out-of-band suppression of the filter, reduces the power consumption, volume, weight of the array, reduces the pressure on algorithm resources, and improves the efficiency of the array.

[0006] In a first aspect, the technical solution adopted by the present invention is a method for adaptively receiving array intermodulation interference cancellation, the method comprising:

[0007] S1: Collect data from all downlink channels and collect data from uplink channels that need interference cancellation;

[0008] S2: construct a fitting intermodulation signal using the downlink signal and the power amplifier intermodulation model, and perform uplink shaping filtering on it to obtain a fitting intermodulation signal containing only the uplink passband part;

[0009] S3: performing a cross-correlation operation on the fitted intermodulation signal filtered in step S2 and the actual uplink interference signal, and comparing the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B;

[0010] S4: Use an optimization algorithm to estimate the cancellation coefficient of the downlink channel set B and the uplink interference, and use the cancellation coefficient to build an anti-interference model. In the anti-interference model, the cancellation coefficient and the downlink signal are combined to obtain a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

[0011] In the present application, the method of digital interference cancellation is adopted, and the optimal cancellation coefficient is calculated by using an optimization algorithm to generate a signal opposite to the downlink signal intermodulation, which can effectively remove the nonlinear interference to the receiving array in the uplink receiving band, improve the quality of the uplink signal, improve the signal-to-noise ratio, reduce the bit error rate, and improve the reliability and data transmission rate of the communication system. Such technical effects are particularly important for communication systems working in complex environments (such as high interference, multi-band sharing, etc.), which helps to improve the spectrum efficiency and overall performance of the system, and because the scheme of the present invention only needs to pay attention to the part where the intermodulation interference falls on the uplink passband, and does not need to offset the intermodulation of all frequency bands, and is in the receiver processing signal, it will not have any impact on the downlink link, so only a smaller sampling rate is needed to achieve the purpose of removing the nonlinear interference to the receiving array in the uplink receiving band, which greatly reduces the algorithm resource pressure.

[0012] Preferably, in step S2, the power amplifier intermodulation model is a Saleh model or a Rapp model or a Volterra series model or other models. In the present application, the selection of the power amplifier intermodulation model can be selected according to the working environment and performance requirements of the power amplifier to achieve the purpose of constructing the optimal fitting intermodulation signal.

[0013] Further preferably, the power amplifier intermodulation model uses a Volterra series model, and the power amplifier intermodulation model actually used is obtained for the component of the signal falling in the uplink passband, and its formula is:

[0014] Y'(k)=y(k)G(t)

[0015] Among them, y(k) is the output of the Volterra series model; G(t) is the output of the uplink shaping filter; Y'(k) represents the output of the power amplifier intermodulation model, which is a fitted intermodulation signal containing only the uplink passband part.

[0016] The Volterra series model selected in the present application can handle the high-order nonlinear effects of the power amplifier, especially when the input signal is strong, the power amplifier exhibits significant nonlinear behavior, and has good flexibility and wide applicability. It can be used to describe various types of nonlinear systems, including various operating modes of the power amplifier. In addition, it can also handle the intermodulation distortion of multi-frequency components. By adjusting the order of the Volterra model (that is, the order of the polynomial terms included), it is possible to achieve a trade-off between different accuracies and computational efficiency, thereby improving the accuracy of the constructed fitted intermodulation signal.

[0017] Preferably, the step S2 further includes performing a band-limiting operation on the power amplifier intermodulation model to align the frequencies of the power amplifier intermodulation model and the uplink shaping filter.

[0018] Since the power amplifier model is based on the downlink signal as the center frequency, and the uplink shaping filter is based on the uplink signal as the center frequency, it is necessary to align the frequencies of the two to avoid spectrum misalignment between the power amplifier and the filter, ensure the phase and frequency consistency of the signal during transmission, ensure that the power amplifier and the filter can operate within the correct frequency bandwidth, improve signal quality, reduce errors caused by inaccurate frequency alignment, and make the constructed fitting intermodulation signal more accurate.

[0019] Preferably, in step S3, the cross-correlation calculation formula is:

[0020]

[0021] Among them, x * (kt) represents the uplink signal; Y′(k) represents the output of the power amplifier intermodulation model; r yx (t) represents the cross-correlation result.

[0022] By comparing the cross-correlation result calculated using the above formula with the preset threshold value, the downlink channel whose intermodulation affects the uplink reception can be quickly found, wherein the threshold value is set according to an empirical value. When the cross-correlation result is greater than the preset threshold value, it means that the intermodulation of the downlink channel affects the uplink reception, and it is necessary to find out these downlink channels that will interfere with the uplink reception, and perform subsequent steps to eliminate the interference within the uplink band.

[0023] Preferably, step S4 includes:

[0024] S41: using the actual uplink interference signal x(k) minus the output Y′(k) of the power amplifier intermodulation model to obtain the error e(k) of the anti-interference model, and obtaining a plurality of cancellation coefficient groups according to the error;

[0025] S42: Select n cancellation coefficient groups with the best cancellation effect from a number of cancellation coefficient groups to form a new initial set, recorded as initial set C = [H1H2H3 ... H n ];

[0026] S43: Optimizing the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

[0027] The cancellation coefficient of the downlink channel set B and the uplink interference is obtained by the above method, so that it can be combined with the downlink signal to generate a cancellation signal with the same magnitude and opposite phase as the uplink interference, and the generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby effectively eliminating the interference falling within the uplink band.

[0028] Preferably, in step S41, obtaining a plurality of compensation coefficients according to the error includes:

[0029] S411: Use optimization algorithm to find a suitable offset coefficient h so that

[0030]

[0031] S412: Since the overdetermined equation has no unique solution, the least square method is used to solve the approximate solution of the optimal offset coefficient, and several offset coefficient groups H are obtained, whose formula is:

[0032] H=(U*U H ) -1 U H X

[0033] Among them, U represents the downlink transmission signal; X represents the uplink reception signal.

[0034] The above method can effectively solve the problem that the overdetermined equation has no unique solution, minimize the error between the obtained offset coefficient and the actual optimal offset coefficient, and improve the anti-interference performance of the system.

[0035] Preferably, the optimization process in step S43 includes:

[0036] S431: Select two groups of cancellation coefficients with the best cancellation effect from the initial set C, then randomly exchange a coefficients therein, and calculate the cancellation errors of the two new groups of cancellation coefficients. If the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst group in the initial set C by more than 1 dB, then add the newly generated cancellation coefficient group to the initial set C to form a new set C1;

[0037] S432: Randomly select two groups of cancellation coefficients in set C1, and randomly exchange a coefficients therein, calculate the cancellation errors of the two new groups of cancellation coefficients, and if the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst performance group in the initial set C by more than 1 dB, then add the newly generated cancellation coefficient group to set C1 to form a new set C2;

[0038] S433: Randomly select a set of offset coefficients from set C2, and then randomly select The number of offset coefficients is m, Indicates rounding up; then the amplitude A of the selected cancellation coefficients is changed to a random value in the interval [0.95A, 1.05A] until the cancellation error of the new cancellation coefficient is more than 1dB better than the cancellation error of the worst performance group in the initial set C, then the newly generated cancellation coefficient group is added to the initial set C to form a new set C3;

[0039] S434: Determine the number of cancellation coefficient groups in the set C3. If the number is greater than 4m, delete several groups of cancellation coefficients with the worst performance until the elements of the set are less than or equal to 4m.

[0040] S435: Repeat steps S431-S434 until the obtained cancellation coefficient can cancel the interference signal below the bottom noise.

[0041] By continuously optimizing the cancellation coefficient through the above steps, it can be ensured that the obtained cancellation coefficient can cancel the interference signal below the noise floor, thereby effectively removing the interference of the nonlinearity in the uplink receiving band to the receiving array.

[0042] On the other hand, the present invention also provides an adaptive receiving array intermodulation interference cancellation device, the device at least comprising a plurality of uplink channels, a plurality of downlink channels and an interference estimation module;

[0043] Wherein, the interference estimation module comprises:

[0044] A data acquisition unit, used to collect data from all downlink channels and to collect data from uplink channels that require interference cancellation;

[0045] An intermodulation signal processing unit is used to construct a fitting intermodulation signal using a downlink signal and a power amplifier intermodulation model, and perform uplink shaping filtering on the fitting intermodulation signal to obtain a fitting intermodulation signal containing only an uplink passband portion;

[0046] A cross-correlation operation unit is used to perform a cross-correlation operation on the fitted intermodulation signal obtained after the intermodulation signal processing unit is processed and the uplink actual interference signal, and compare the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B;

[0047] The interference cancellation unit is used to use an optimization algorithm to estimate the cancellation coefficients of the downlink channel set B and the uplink interference, and use the cancellation coefficients to build an anti-interference model. In the anti-interference model, the cancellation coefficients are combined with the downlink signal to generate a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

[0048] Preferably, the interference cancellation unit further includes:

[0049] A cancellation coefficient acquisition component is used to obtain the error e(k) of the anti-interference model by subtracting the output Y′(k) of the power amplifier intermodulation model from the actual uplink interference signal x(k), and obtain a number of cancellation coefficient groups according to the error;

[0050] The compensation coefficient selection component is used to select n compensation coefficient groups with the best compensation effect from a number of compensation coefficient groups to form a new initial set, which is recorded as the initial set C = [H1H2H3…H n ];

[0051] The cancellation coefficient optimization component is used to optimize the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The present invention adopts a digital interference cancellation method and uses an optimization algorithm to find the cancellation coefficient with the best reception interference cancellation effect. When the antenna is working, a signal with a phase opposite to the intermodulation of the downlink signal falling in the uplink band is generated to cancel the influence of the downlink intermodulation on the uplink reception. In addition, since the present solution only needs to focus on the part of the intermodulation interference falling in the uplink passband, and does not need to cancel the intermodulation of all frequency bands, only a smaller sampling rate is required to achieve the purpose, reducing the pressure on algorithm resources. At the same time, the algorithm used in the present invention is based on correlation and optimization algorithms, and will not generate non-interference signal components and will not affect the original uplink signal. Therefore, the present patent effectively solves the out-of-band interference of transmission on reception in the antenna array, greatly reduces the demand for out-of-band suppression of the filter by the transmission channel, reduces the power consumption, volume and weight of the entire array, and improves the efficiency of the entire array. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of the method flow provided in this embodiment.

[0055] Figure 2 This is a schematic diagram of the device structure provided in this embodiment. DETAILED DESCRIPTION

[0056] The drawings of the present invention are only for illustrative purposes and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0057] Example 1

[0058] like Figure 1 As shown, this embodiment provides an adaptive receiving array intermodulation interference cancellation method, the method comprising:

[0059] S1: Collect data from all downlink channels and collect data from uplink channels that need interference cancellation;

[0060] S2: construct a fitting intermodulation signal using the downlink signal and the power amplifier intermodulation model, and perform uplink shaping filtering on it to obtain a fitting intermodulation signal containing only the uplink passband part;

[0061] S3: performing a cross-correlation operation on the fitted intermodulation signal filtered in step S2 and the actual uplink interference signal, and comparing the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B;

[0062] S4: Use an optimization algorithm to estimate the cancellation coefficient of the downlink channel set B and the uplink interference, and use the cancellation coefficient to build an anti-interference model. In the anti-interference model, the cancellation coefficient and the downlink signal are combined to obtain a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

[0063] In the present application, the method of digital interference cancellation is adopted, and the optimal cancellation coefficient is calculated by using an optimization algorithm to generate a signal opposite to the downlink signal intermodulation, which can effectively remove the nonlinear interference to the receiving array in the uplink receiving band, improve the quality of the uplink signal, improve the signal-to-noise ratio, reduce the bit error rate, and improve the reliability and data transmission rate of the communication system. Such technical effects are particularly important for communication systems working in complex environments (such as high interference, multi-band sharing, etc.), which helps to improve the spectrum efficiency and overall performance of the system, and because the scheme of the present invention only needs to pay attention to the part where the intermodulation interference falls on the uplink passband, and does not need to offset the intermodulation of all frequency bands, and is in the receiver processing signal, it will not have any impact on the downlink link, so only a smaller sampling rate is needed to achieve the purpose of removing the nonlinear interference to the receiving array in the uplink receiving band, which greatly reduces the algorithm resource pressure.

[0064] Preferably, in step S2, the power amplifier intermodulation model is a Saleh model or a Rapp model or a Volterra series model or other models. In the present application, the selection of the power amplifier intermodulation model can be selected according to the working environment and performance requirements of the power amplifier to achieve the purpose of constructing the optimal fitting intermodulation signal.

[0065] Further preferably, the power amplifier intermodulation model in this embodiment uses a Volterra series model, and its expression is as follows:

[0066] y(k)=y0+∑h1(m)u(km)+∑h2(m1,m2)u(k-m1)u(k-m2)+…

[0067] Among them, u(k) is the downlink signal, y(k) is the output of the Volterra series model, and h is the coefficient corresponding to the model;

[0068] In addition, this solution only focuses on the signal component that falls in the uplink passband. Therefore, the formula of the actual power amplifier intermodulation model is:

[0069] Y′(k)=y(k)G(t) where y(k) is the output of the Volterra series model; G(t) is the output of the uplink shaping filter; Y′(k) represents the output of the power amplifier intermodulation model, which is a fitted intermodulation signal that only contains the uplink passband part.

[0070] The Volterra series model selected in the present application can handle the high-order nonlinear effects of the power amplifier, especially when the input signal is strong, the power amplifier exhibits significant nonlinear behavior, and has good flexibility and wide applicability. It can be used to describe various types of nonlinear systems, including various operating modes of the power amplifier. In addition, it can also handle the intermodulation distortion of multi-frequency components. By adjusting the order of the Volterra model (that is, the order of the polynomial terms included), it is possible to achieve a trade-off between different accuracies and computational efficiency, thereby improving the accuracy of the constructed fitted intermodulation signal.

[0071] Preferably, the step S2 further includes performing a band-limiting operation on the power amplifier intermodulation model to align the frequencies of the power amplifier intermodulation model and the uplink shaping filter.

[0072] Since the power amplifier model is based on the downlink signal as the center frequency, and the uplink shaping filter is based on the uplink signal as the center frequency, it is necessary to align the frequencies of the two to avoid spectrum misalignment between the power amplifier and the filter, ensure the phase and frequency consistency of the signal during transmission, ensure that the power amplifier and the filter can operate within the correct frequency bandwidth, improve signal quality, reduce errors caused by inaccurate frequency alignment, and make the constructed fitting intermodulation signal more accurate.

[0073] Preferably, in step S3, the cross-correlation calculation formula is:

[0074]

[0075] Among them, x * (kt) represents the uplink signal; Y′(k) represents the output of the power amplifier intermodulation model; r yx (t) represents the cross-correlation result.

[0076] By comparing the cross-correlation result calculated using the above formula with the preset threshold value, the downlink channel whose intermodulation affects the uplink reception can be quickly found, wherein the threshold value is set according to an empirical value. When the cross-correlation result is greater than the preset threshold value, it means that the intermodulation of the downlink channel affects the uplink reception, and it is necessary to find out these downlink channels that will interfere with the uplink reception, and perform subsequent steps to eliminate the interference within the uplink band.

[0077] Preferably, step S4 includes:

[0078] S41: using the actual uplink interference signal x(k) minus the output Y′(k) of the power amplifier intermodulation model to obtain the error e(k) of the anti-interference model, and obtaining a plurality of cancellation coefficient groups according to the error;

[0079] Specifically, in step S41, the calculation formula of the error is:

[0080] e(k)=x(k)-Y′(k)

[0081] Then use the optimization algorithm to find the appropriate compensation coefficient h so that:

[0082]

[0083] Since the overdetermined equation has no unique solution, the least squares method is used to solve the approximate solution of the optimal offset coefficient, and several offset coefficient groups H are obtained, whose formula is:

[0084] H=(U*U H ) -1 U H X

[0085] Among them, U represents the downlink transmission signal; X represents the uplink reception signal.

[0086] A series of cancellation coefficients can be obtained in the above manner. If these cancellation coefficients are unable to cancel the interference signal below the noise floor, the following operations are required to optimize the cancellation coefficients so as to minimize the error between the obtained cancellation coefficients and the actual optimal cancellation coefficients, thereby improving the anti-interference performance of the system.

[0087] S42: Select n cancellation coefficient groups with the best cancellation effect from a number of cancellation coefficient groups to form a new initial set, recorded as initial set C = [H1H2H3 ... H n ];

[0088] S43: Optimizing the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

[0089] Specifically, the optimization process in step S43 includes:

[0090] Step S431: First, two groups of cancellation coefficients with the best cancellation effect are selected from the initial set C, and then a coefficients are randomly exchanged, and the cancellation errors of the two new groups of cancellation coefficients are calculated. If the cancellation error of the new cancellation coefficient is better than the cancellation error of the worst group in the initial set C by more than 1dB, the newly generated cancellation coefficient group is added to the initial set C to form a new set C1;

[0091] Step S432: randomly select two groups of cancellation coefficients in set C1, and randomly exchange a coefficients therein, calculate the cancellation errors of the two new groups of cancellation coefficients, and if the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst performance group in the initial set C by more than 1 dB, then add the newly generated cancellation coefficient group to set C1 to form a new set C2;

[0092] Step S433: Randomly select a set of offset coefficients from set C2, and then randomly select The number of offset coefficients is m, Indicates rounding up; then the amplitude A of the selected cancellation coefficients is changed to a random value in the interval [0.95A, 1.05A] until the cancellation error of the new cancellation coefficient is more than 1dB better than the cancellation error of the worst performance group in the initial set C, then the newly generated cancellation coefficient group is added to the initial set C to form a new set C3;

[0093] Step S434: Determine the number of cancellation coefficient groups in set C3. If it is greater than 4m, delete the worst performing groups of cancellation coefficients until the number of elements in the set is less than or equal to 4m.

[0094] Step S435: Repeat steps S431-S434 until the obtained cancellation coefficient can cancel the interference signal below the bottom noise.

[0095] By continuously optimizing the cancellation coefficient through the above steps, it can be ensured that the obtained cancellation coefficient can cancel the interference signal below the noise floor, thereby effectively removing the interference of the nonlinearity in the uplink receiving band to the receiving array.

[0096] The obtained downlink channel set B and the cancellation coefficient of the uplink interference are used to combine them with the downlink signal to generate a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase, and the generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby effectively eliminating the interference falling within the uplink band.

[0097] Example 2

[0098] like Figure 2 As shown, this embodiment provides an adaptive receiving array intermodulation interference cancellation device, which includes at least a plurality of uplink channels, a plurality of downlink channels and an interference estimation module; one end of the interference estimation module is connected behind the DBF module of the transmitting channel, and is used to collect data from the transmitting channel that needs to perform interference cancellation; one end is connected between the DAC+down modulation module and the DBF module of the receiving channel, and is used to collect data from all receiving channels.

[0099] Specifically, the interference estimation module includes:

[0100] A data acquisition unit, used to collect data from all downlink channels and to collect data from uplink channels that require interference cancellation;

[0101] An intermodulation signal processing unit is used to construct a fitting intermodulation signal using a downlink signal and a power amplifier intermodulation model, and perform uplink shaping filtering on the fitting intermodulation signal to obtain a fitting intermodulation signal containing only an uplink passband portion;

[0102] A cross-correlation operation unit is used to perform a cross-correlation operation on the fitted intermodulation signal obtained after the intermodulation signal processing unit is processed and the uplink actual interference signal, and compare the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B;

[0103] The interference cancellation unit is used to use an optimization algorithm to estimate the cancellation coefficients of the downlink channel set B and the uplink interference, and use the cancellation coefficients to build an anti-interference model. In the anti-interference model, the cancellation coefficients are combined with the downlink signal to generate a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

[0104] Preferably, in the intermodulation signal processing unit, the power amplifier intermodulation model used is a Volterra series model, and its expression is as follows:

[0105] y(k)=y0+∑h1(m)u(km)+∑h2(m1,m2)u(k-m1)u(k-m2)+…

[0106] Among them, u(k) is the downlink signal, y(k) is the output of the Volterra series model, and h is the coefficient corresponding to the model;

[0107] In addition, this solution only focuses on the signal component that falls in the uplink passband. Therefore, the formula of the actual power amplifier intermodulation model is:

[0108] Y′(k)=y(k)G(t) where y(k) is the output of the Volterra series model; G(t) is the output of the uplink shaping filter; Y′(k) represents the output of the power amplifier intermodulation model, which is a fitted intermodulation signal that only contains the uplink passband part.

[0109] And because the power amplifier model is based on the downlink signal as the center frequency, and the uplink shaping filter is based on the uplink signal as the center frequency, in this embodiment, the frequencies of the two are also aligned to avoid spectrum misalignment between the power amplifier and the filter, ensure the phase and frequency consistency of the signal during transmission, ensure that the power amplifier and the filter can operate within the correct frequency bandwidth, improve signal quality, reduce errors caused by inaccurate frequency alignment, and make the constructed fitting intermodulation signal more accurate.

[0110] Preferably, in the cross-correlation operation unit, the cross-correlation operation formula is:

[0111]

[0112] Among them, x * (kt) represents the uplink signal; Y′(k) represents the output of the power amplifier intermodulation model; r yx (t) represents the cross-correlation result.

[0113] The above formula can be used to calculate the cross-correlation result between the filtered fitting intermodulation signal and the uplink actual interference signal, and then the cross-correlation operation result is compared with the preset threshold value through the comparison component in the cross-correlation operation unit. When the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, otherwise it means that the intermodulation of the downlink channel has no impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B, and then the obtained set B is sent to the interference cancellation unit for interference cancellation processing.

[0114] Preferably, the interference cancellation unit further includes:

[0115] A cancellation coefficient acquisition component is used to obtain the error e(k) of the anti-interference model by subtracting the output Y′(k) of the power amplifier intermodulation model from the actual uplink interference signal x(k), and obtain a number of cancellation coefficient groups H according to the error;

[0116] The compensation coefficient selection component is used to select n compensation coefficient groups with the best compensation effect from a number of compensation coefficient groups to form a new initial set, which is recorded as the initial set C = [H1H2H3…H n ];

[0117] The cancellation coefficient optimization component is used to optimize the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

[0118] Specifically, the processing flow in the offset coefficient optimization component includes:

[0119] First, two sets of cancellation coefficients with the best cancellation effect are selected from the initial set C, and then a coefficients are randomly exchanged, and the cancellation errors of the two new sets of cancellation coefficients are calculated. If the cancellation error of the new cancellation coefficient is better than the cancellation error of the worst performance group in the initial set C by more than 1dB, the newly generated cancellation coefficient group is added to the initial set C to form a new set C1;

[0120] Then randomly select two groups of cancellation coefficients in set C1, and randomly exchange a coefficients therein, calculate the cancellation errors of the two new groups of cancellation coefficients, and if the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst performance group in the initial set C by more than 1dB, then add the newly generated cancellation coefficient group to set C1 to form a new set C2;

[0121] Then randomly select a set of offset coefficients from set C2, and then randomly select The number of offset coefficients is m, Indicates rounding up; then the amplitude A of the selected cancellation coefficients is changed to a random value in the interval [0.95A, 1.05A] until the cancellation error of the new cancellation coefficient is better than the cancellation error of the worst performance group in the initial set C by more than 1dB, then the newly generated cancellation coefficient group is added to the initial set C to form a new set C3; and the number of cancellation coefficient groups in set C3 is determined. If it is greater than 4m, the worst performance groups of cancellation coefficients are deleted until the elements of the set are less than or equal to 4m;

[0122] Finally, the above steps are repeated until the obtained cancellation coefficient can cancel the interference signal below the noise floor, thereby achieving continuous optimization of the cancellation coefficient, ensuring that the obtained cancellation coefficient can cancel the interference signal below the noise floor, and effectively removing the interference of nonlinearity in the uplink receiving band to the receiving array.

[0123] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An adaptive receiving array intermodulation interference cancellation method, characterized in that: The method comprises: S1: Collect data from all downlink channels and collect data from uplink channels that need interference cancellation; S2: Based on the collected data, a fitting intermodulation signal is constructed using the downlink signal and the power amplifier intermodulation model, and an uplink shaping filter is performed on the fitting intermodulation signal to obtain a fitting intermodulation signal containing only the uplink passband part; S3: performing a cross-correlation operation on the fitted intermodulation signal filtered in step S2 and the actual uplink interference signal, and comparing the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B; S4: Use an optimization algorithm to estimate the cancellation coefficient of the downlink channel set B and the uplink interference, and use the cancellation coefficient to build an anti-interference model. In the anti-interference model, the cancellation coefficient and the downlink signal are combined to obtain a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

2. The method for canceling intermodulation interference of an adaptive receiving array according to claim 1, characterized in that: In the step S2, the power amplifier intermodulation model is a Saleh model, a Rapp model, a Volterra series model or other models.

3. The method for canceling intermodulation interference of an adaptive receiving array according to claim 2, characterized in that: The power amplifier intermodulation model uses the Volterra series model, and the actual power amplifier intermodulation model is obtained for the component of the signal falling in the uplink passband, and its formula is: Y′(k)=y(k)G(t) Among them, y(k) is the output of the Volterra series model; G(t) is the output of the uplink shaping filter; Y′(k) represents the output of the power amplifier intermodulation model, which is a fitted intermodulation signal containing only the uplink passband part.

4. The method for canceling intermodulation interference of an adaptive receiving array according to claim 3, characterized in that: The step S2 also includes performing a band-limiting operation on the power amplifier intermodulation model to align the frequency points of the power amplifier intermodulation model and the uplink shaping filter.

5. The method for canceling intermodulation interference of an adaptive receiving array according to claim 4, characterized in that: In step S3, the cross-correlation calculation formula is: Among them, x * (kt) represents the uplink signal; Y′(k) represents the output of the power amplifier intermodulation model; r yx (t) represents the cross-correlation result.

6. The method for canceling intermodulation interference of an adaptive receiving array according to claim 5, characterized in that: The step S4 includes: S41: using the actual uplink interference signal x(k) minus the output Y′(k) of the power amplifier intermodulation model to obtain the error e(k) of the anti-interference model, and obtaining a plurality of cancellation coefficient groups according to the error; S42: Select n cancellation coefficient groups with the best cancellation effect from a number of cancellation coefficient groups to form a new initial set, recorded as initial set C = [H1H2H3 ... H n ]; S43: Optimizing the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

7. The method for canceling intermodulation interference of an adaptive receiving array according to claim 6, characterized in that: In the step S41, obtaining a plurality of compensation coefficients according to the error includes: S411: Use optimization algorithm to find a suitable offset coefficient h so that S412: Since the overdetermined equation has no unique solution, the least square method is used to solve the approximate solution of the optimal offset coefficient, and several offset coefficient groups H are obtained, whose formula is: H=(U*U H ) -1 U H X Among them, U represents the downlink transmission signal; X represents the uplink reception signal.

8. The method for canceling intermodulation interference of an adaptive receiving array according to claim 6, characterized in that: In step S43, the optimization process includes: S431: Select two groups of cancellation coefficients with the best cancellation effect from the initial set C, then randomly exchange a coefficients therein, and calculate the cancellation errors of the two new groups of cancellation coefficients. If the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst group in the initial set C by more than 1 dB, then add the newly generated cancellation coefficient group to the initial set C to form a new set C1; S432: Randomly select two groups of cancellation coefficients in set C1, and randomly exchange a coefficients therein, calculate the cancellation errors of the two new groups of cancellation coefficients, and if the cancellation error of the new cancellation coefficients is better than the cancellation error of the worst performance group in the initial set C by more than 1 dB, then add the newly generated cancellation coefficient group to set C1 to form a new set C2; S433: Randomly select a set of offset coefficients from set C2, and then randomly select The number of offset coefficients is m, Indicates rounding up; then the amplitude A of the selected cancellation coefficients is changed to a random value in the interval [0.95A, 1.05A] until the cancellation error of the new cancellation coefficient is more than 1dB better than the cancellation error of the worst performance group in the initial set C, then the newly generated cancellation coefficient group is added to the initial set C to form a new set C3; S434: Determine the number of cancellation coefficient groups in the set C3. If the number is greater than 4m, delete several groups of cancellation coefficients with the worst performance until the elements of the set are less than or equal to 4m. S435: Repeat steps S431-S434 until the obtained cancellation coefficient can cancel the interference signal below the bottom noise.

9. An adaptive receiving array intermodulation interference cancellation device, characterized in that: The device at least includes a plurality of uplink channels, a plurality of downlink channels and an interference estimation module; Wherein, the interference estimation module comprises: A data acquisition unit, used to collect data from all downlink channels and to collect data from uplink channels that require interference cancellation; An intermodulation signal processing unit is used to construct a fitting intermodulation signal using a downlink signal and a power amplifier intermodulation model, and perform uplink shaping filtering on the fitting intermodulation signal to obtain a fitting intermodulation signal containing only an uplink passband portion; A cross-correlation operation unit is used to perform a cross-correlation operation on the fitted intermodulation signal obtained after the intermodulation signal processing unit is processed and the uplink actual interference signal, and compare the cross-correlation operation result with a preset threshold value. If the cross-correlation result is greater than the threshold value, it means that the intermodulation of the downlink channel has an impact on the uplink reception, and then the collection of all downlink channels that will interfere with the uplink reception is recorded as B; The interference cancellation unit is used to use an optimization algorithm to estimate the cancellation coefficients of the downlink channel set B and the uplink interference, and use the cancellation coefficients to build an anti-interference model. In the anti-interference model, the cancellation coefficients are combined with the downlink signal to generate a cancellation signal that is equal to the uplink interference in magnitude and opposite in phase. The generated cancellation signal is added or subtracted from the uplink signal to affect the phase, thereby eliminating the interference falling within the uplink band.

10. The adaptive receiving array intermodulation interference cancellation device according to claim 9, characterized in that: The interference cancellation unit also includes: A cancellation coefficient acquisition component is used to obtain the error e(k) of the anti-interference model by subtracting the output Y′(k) of the power amplifier intermodulation model from the actual uplink interference signal x(k), and obtain a number of cancellation coefficient groups according to the error; The compensation coefficient selection component is used to select n compensation coefficient groups with the best compensation effect from a number of compensation coefficient groups to form a new initial set, which is recorded as the initial set C = [H1H2H3…H n ]; The cancellation coefficient optimization component is used to optimize the cancellation coefficients in the initial set C until the obtained cancellation coefficients can cancel the interference signal below the bottom noise.

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