A self-measurement method of coupling matrix of a transceiving simultaneous array

Abstract

The application discloses a self-measurement method of a coupling matrix of a transceiving simultaneous array, and comprises the following steps: obtaining a theoretical antenna coupling matrix of the transceiving simultaneous array through simulation; measuring and storing transmitting-receiving array amplitude and phase errors of the transceiving simultaneous array; determining attenuation values required for closing the rest of transmitting channels when transmitting a single signal according to the theoretical antenna coupling matrix of the transceiving simultaneous array, and determining a receiving signal power range; dynamically changing transceiving configurations and receiving gains of the transceiving simultaneous array so that the receiving signal power is within the receiving signal power range; and measuring coupling channels of the transceiving simultaneous array under each transceiving configuration to obtain a coupling matrix. The application realizes self-interference channel estimation of a large-scale transceiving simultaneous phased array system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transceiving simultaneous array coupling matrix measurement, and more particularly to a coupling matrix self-measurement method of a transceiving simultaneous array. BACKGROUND

[0002] With the rapid development of wireless communication technology, the demand for spectrum resources has increased dramatically, and how to more efficiently use limited spectrum resources has become a problem to be solved.

[0003] Transceiving simultaneous technology, also known as in-band full-duplex technology, can simultaneously realize transmission and reception on the same frequency band, thereby improving the utilization rate of spectrum by one time and greatly relieving the pressure of spectrum resource shortage. The biggest challenge of transceiving simultaneous technology is the strong self-interference generated by the transmission signal to the reception signal, which will saturate the reception end and drown the signal of interest.

[0004] With the development of technology, the existing research on self-interference signal suppression is carried out around the three aspects of propagation domain, analog domain and digital domain. However, compared with the digital domain method, the isolation realized by the antenna and analog domain method is limited, especially in a large-scale phased array with strong SI of multi-dimensional cross-coupling between the transmission end and the reception end, the radio frequency cancellation will bring huge cost to the system in terms of size, complexity and power consumption.

[0005] Beamforming is an effective technology that can improve the isolation of the STAR phased array in the spatial domain, and a large number of studies have proposed various algorithms for different types of arrays, which effectively realize the isolation of self-interference signals in the spatial domain. The self-interference coupling matrix describes the self-interference channel between the transmitting antenna and the receiving antenna, and is an important parameter of beamforming.

[0006] The existing beamforming methods applied to transceiving simultaneous array systems all need the coupling channel information from the transmitting antenna to the receiving antenna, however, the research on coupling channel estimation is usually used for digital and analog cancellation, and the coupling channels of different transmitting antennas are not distinguished, and the coupling matrix estimation between multiple transmitting and receiving antennas for beamforming self-interference suppression receives less attention.

[0007] There are three ways to obtain the coupling matrix in the existing research on adaptive beamforming:

[0008] First, the theoretical value of antenna array coupling is simulated by using HFSS or near-field radiation model, which has the disadvantage of being too idealized and not considering the complex time-varying channel environment in actual application.

[0009] Second, a vector network analyzer is used in engineering to measure, which has the disadvantages of large workload, lack of flexibility for system design iteration and environmental change, easy introduction of errors when the antenna is disconnected from the vector network analyzer, and difficulty in forming a fixed system for transceiving simultaneous phased array.

[0010] Third, the traditional channel estimation algorithm, these algorithms are usually oriented wireless communication channel application scenarios, and self-interference channel estimation in the reference source, data volume, signal-to-noise ratio, timeliness, etc. There are obvious differences. At the same time, the large-scale analog phased array cannot allocate different pilot sequences for each transmit channel, so it is not suitable for channel estimation method based on pilot sequence.

[0011] The existing research on the coupling matrix estimation between the transmitting and receiving antennas usually needs a coupler to couple the transmitting and receiving signals for channel estimation, which is not suitable for transceiving simultaneous systems without coupling links. SUMMARY

[0012] The application provides a self-measurement method of a coupling matrix of a transceiving simultaneous array, which solves the technical problems of inaccurate coupling matrix measurement, large workload and unsuitable application scenarios of the beam forming method of the transceiving simultaneous array system in the prior art.

[0013] To solve the above technical problems, the technical scheme of the application is as follows:

[0014] The application provides a self-measurement method of a coupling matrix of a transceiving simultaneous array, which includes the following steps:

[0015] The theoretical antenna coupling matrix of the transceiving simultaneous array is obtained through simulation;

[0016] The transmitting and receiving array amplitude and phase errors of the transceiving simultaneous array are measured and stored;

[0017] According to the theoretical antenna coupling matrix of the transmitting and receiving signals of the transceiving simultaneous array, the attenuation value required for closing the remaining transmitting channels when transmitting a single signal is determined, and the receiving signal power range is determined;

[0018] The transceiving configuration and receiving gain of the transceiving simultaneous array are dynamically changed, so that the receiving signal power is within the receiving signal power range;

[0019] The coupling channel under each transceiving configuration of the transceiving simultaneous array is measured to obtain the coupling matrix.

[0020] In the above technical means, the coupling matrix between the transmitting antennas and the receiving antennas is estimated by controlling the array transmitting antennas to transmit in turn, the receiving antennas to receive in turn, and the receiving power to be adaptively adjusted, and then the adaptive beam forming and digital cancellation of the self-interference signal are performed, and the isolation of the transceiving simultaneous array is improved.

[0021] Further, the theoretical antenna coupling matrix of the transceiving simultaneous array is obtained through simulation, including:

[0022] The theoretical antenna coupling matrix of the simultaneous transmit receive array is a complex matrix of JxK, where the element in the jth row and the kth column defines the propagation coefficient from the jth transmit antenna to the kth receive antenna, J and K are the total number of transmit antennas and receive antennas respectively;

[0023] The theoretical antenna coupling matrix of the simultaneous transmit receive array is obtained by HFSS simulation.

[0024] Further, the transmit receive array amplitude and phase error includes transmit amplitude and phase error Γ t and receive amplitude and phase error Γ r , wherein the transmit amplitude and phase error Γ t is the propagation coefficient from the digital-to-analog converter at the end of the transmit link to the antenna when the transmit link gain and the beamforming weight of the simultaneous transmit receive array are equal, and the receive amplitude and phase error Γ r is the propagation coefficient from the analog-to-digital converter at the end of the receive link to the antenna when the receive link gain and the beamforming weight of the simultaneous transmit receive array are equal.

[0025] Further, the transmit receive array amplitude and phase error of the simultaneous transmit receive array is measured and stored, including:

[0026] The transmit receive array amplitude and phase error of the simultaneous transmit receive array is measured and stored by a vector network analyzer or near-field measurement.

[0027] Further, according to the theoretical antenna coupling matrix of the transmit signal and the receive signal of the simultaneous transmit receive array, the attenuation value required when the remaining transmit channels are closed when a single transmit signal is transmitted is determined, and the receive signal power range is determined, including:

[0028] Defining the attenuation value S of the antenna switch filter of the simultaneous transmit receive array as the attenuation value required when a single antenna of the transmit array transmits and the remaining transmit channels are closed;

[0029] Iterating through different attenuation values S of the antennas of the simultaneous transmit receive array;

[0030] For each attenuation value S, let one transmit channel transmit and the remaining closed transmit channels apply the attenuation value S, and use Monte Carlo simulation to simulate the influence of the remaining closed transmit channels on the digital-to-analog converter coupling self-interference at the receive antenna when random phase shifts exist;

[0031] Select the attenuation value S with less influence;

[0032] Confirm whether there is a hardware configuration of the transmit link of the simultaneous transmit receive array that can reach the above attenuation value;

[0033] If so, the receive signal power range corresponding to the attenuation value S with less influence is obtained.

[0034] Further, the influence of the random phase shift of the rest closed transmitting channels on the coupled self-interference at the receiving antenna is simulated by Monte Carlo, including:

[0035] The influence of the random phase shift of the rest closed transmitting channels on the coupled self-interference at the receiving antenna is evaluated by the relative mean square error, wherein the relative mean square error is defined as the ratio of the channel estimation mean square error to the square of the amplitude of the channel estimation result.

[0036] Further, the receiving signal power range corresponding to the less influenced attenuation value S is obtained, including:

[0037]

[0038] In the formula, P kj is the receiving signal power when the jth antenna transmits alone and the kth antenna receives alone, V ref is the reference voltage of the analog-to-digital converter of the receiving link in the transceiving simultaneous array, P min is the minimum receiving signal power ensuring that the relative mean square error in the self-interference coupling channel estimation is small and is not affected by the quantization error.

[0039] Further, the transceiving configuration and the receiving gain of the transceiving simultaneous array are dynamically changed so that the receiving signal power is within the receiving signal power range, including:

[0040] The transmitting antennas of the transceiving simultaneous array are controlled to transmit alone in turn, and the receiving antennas of the transceiving simultaneous array are controlled to receive alone in turn.

[0041] The receiving gain of the receiving antennas of the transceiving simultaneous array is controlled so that the receiving signal power is within the receiving signal power range.

[0042] The transmitting signal, the receiving signal and the receiving gain at each configuration are saved.

[0043] Further, the receiving gain of the receiving antennas of the transceiving simultaneous array is controlled so that the receiving signal power is within the receiving signal power range, including:

[0044] The receiving signal power is calculated.

[0045] If the receiving signal power is less than the minimum receiving signal power, the receiving gain is increased:

[0046] G kj (m+1)= G kj (m)+Δ G ,P kj ≤P min

[0047] If the receiving signal power is greater than the maximum receiving signal power, the receiving gain is decreased:

[0048]

[0049] where m is the iteration number of adjusting the receive gain, G kj (m) is the receive gain when the iteration number is m, AG is the adjustment step of the receive gain, with the unit of dB;

[0050] If the received signal power is within the range of the received signal power, the loop is ended, the difference between the receive gain at this time and the initial receive gain is calculated, and the transmit power difference matrix G Δ,dB .

[0051] Further, the coupling channel under each kind of transceiving configuration of the transceiving simultaneous array is measured, and the coupling matrix is obtained:

[0052] The self-interference channel estimation between the antennas is obtained by using the least square channel estimation method:

[0053]

[0054] wherein, indicates the self-interference channel between the jth transmitting antenna and the kth receiving antenna obtained by using the least square channel estimation method, Y kj (e jω ), X kj (e jω ) respectively indicate the Fourier transform of the received signal and the transmitted signal, Γ tj indicates the transmitting amplitude and phase error of the jth antenna, Γ rk indicates the receiving amplitude and phase error of the kth antenna, G Δ,kj is the receive gain adjustment difference when the antenna j transmits alone and the antenna k receives alone, with the unit converted from dB to 1;

[0055] The estimated coupling matrix is constructed:

[0056]

[0057] wherein, is the coupling matrix estimated by using the least square channel estimation method;

[0058] The self-interference channel estimation between the antennas is obtained by using the recursive least square channel estimation method:

[0059]

[0060] wherein, indicates the self-interference channel between the jth transmitting antenna and the kth receiving antenna obtained by using the recursive least square channel estimation method, N is the filter length, and wkj,i is the i-th weight after convergence of the recursive least square algorithm, i = 1,..., N-1, Γ tj represents the transmitting amplitude and phase error of the j-th transmitting antenna, Γ rk represents the receiving amplitude and phase error of the k-th receiving antenna, G Δ,kj is the receiving gain adjustment difference value when the antenna j transmits alone and the antenna k receives alone, the unit is converted from dB to 1;

[0061] construct the estimated coupling matrix:

[0062]

[0063] in the formula, is the coupling matrix estimated by using the recursive least square channel estimation method.

[0064] Compared with the prior art, the beneficial effects of the technical scheme of the present application are:

[0065] 1. The present application is conducive to engineering implementation, can adapt to complex time-varying self-interference channel environment, realizes in-machine measurement of the coupling matrix, and is conducive to actual engineering implementation of the transmitting-receiving simultaneous phased array;

[0066] 2. The present application is applicable to analog and digital transmitting-receiving simultaneous array systems with or without cancellation architecture, and can effectively improve the transmitting-receiving isolation of the system;

[0067] 3. The present application estimates the coupling matrix by transmitting and receiving signals transmitted and received by the transmitting and receiving antennas alone, reduces the calculation amount and error accumulation of the matrix inversion and estimation of multiple intermediate variables in the prior art, and realizes fast and accurate estimation of the coupling matrix between the transmitting-receiving antennas of the transmitting-receiving simultaneous phased array. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 is a flowchart of a coupling matrix self-measurement method of a transmitting-receiving simultaneous array provided by an embodiment of the present application;

[0069] Figure 2 is a structural schematic diagram of a transmitting-receiving simultaneous array provided by an embodiment of the present application;

[0070] Figure 3 is an array antenna arrangement schematic diagram of a transmitting-receiving simultaneous array provided by an embodiment of the present application;

[0071] Figure 4 is an algorithm flowchart provided by an embodiment of the present application;

[0072] Figure 5 is a diagram showing the influence of the coupling error on the attenuation value of the closed channel switch filter provided by an embodiment of the present application;

[0073] Figure 6 The relative mean square error of channel estimation provided by the embodiment of the present application is affected by the proportion of received signal to received ADC bits, as shown in the schematic diagram;

[0074] Figure 7 The amplitude and phase of the coupling matrix estimated by the LS and RLS methods provided by the embodiment of the present application are shown in the schematic diagram;

[0075] Figure 8 The amplitude and phase of the coupling matrix estimated by the LS and RLS methods provided by the embodiment of the present application and the error of the coupling matrix true value estimation are shown in the schematic diagram;

[0076] Figure 9 The self-interference signal power and effective isotropic isolation of different scanning angles provided by the embodiment of the present application are shown in the schematic diagram. DETAILED DESCRIPTION

[0077] The accompanying drawings are only used for illustrative purposes and should not be construed as limiting the patent;

[0078] In order to better illustrate the embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product;

[0079] For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0080] The technical solutions of the present application will be further described below in combination with the drawings and embodiments.

[0081] Embodiment 1

[0082] The embodiment provides a self-measurement method of a coupling matrix of a transceiving simultaneous array, as shown in Figure 1 and Figure 4 , comprising the following steps:

[0083] Obtain the theoretical antenna coupling matrix of the transceiving simultaneous array through simulation;

[0084] Measure and store the amplitude and phase errors of the transmitting and receiving array of the transceiving simultaneous array;

[0085] According to the theoretical antenna coupling matrix of the transmitting and receiving array of the transceiving simultaneous array, determine the attenuation value required when closing the remaining transmitting channels when transmitting a single signal, and determine the receiving signal power range;

[0086] Dynamically change the transceiving configuration and receiving gain of the transceiving simultaneous array so that the receiving signal power is within the receiving signal power range;

[0087] Measure the coupling channel under each transceiving configuration of the transceiving simultaneous array to obtain the coupling matrix.

[0088] Example 2

[0089] This embodiment further describes the self-measurement method of the coupling matrix of the simultaneous transmit and receive array, based on Embodiment 1.

[0090] The simultaneous transmit and receive array system described in this embodiment is an analog array, without a reference link architecture. The transmit RF link includes a DAC, mixer, power amplifier, power divider, digitally controlled attenuator, digitally controlled phase shifter, etc.; the receive link includes low-noise amplifier, filter, mixer, ADC, and other receiving components, such as... Figure 2 As shown.

[0091] In a further embodiment, the method further includes determining configuration parameters for the simultaneous transmit and receive array, including:

[0092] Determine the number of transmit and receive antennas in the simultaneous transmit and receive array system;

[0093] Determine the receive gain of the simultaneous transmit and receive array;

[0094] Determine the center frequency at which the transmit and receive array system operates.

[0095] In a further embodiment, obtaining the theoretical antenna coupling matrix of the simultaneous transmit and receive array through simulation includes:

[0096] The theoretical antenna coupling matrix of the simultaneous transmit and receive array is a complex matrix of J×K, where the element in the j-th row and k-th column is defined as the propagation coefficient from the j-th transmit antenna to the k-th receive antenna, and J and K are the total number of transmit antennas and receive antennas, respectively.

[0097] In this embodiment, the simultaneous transmit and receive array is an 8-transmit, 4-receive uniform linear array, and the array elements are coaxially fed helical antennas. The upper left 1×8 array is the transmit array, and the lower right 1×4 array is the receive array, as shown below. Figure 3 As shown; in this embodiment of the invention, the number of transmit and receive links J=8 and K=4, then the size of the ideal transmit and receive antenna coupling matrix of the simultaneous transmit and receive array is a complex matrix of 4 rows and 8 columns, i.e.

[0098] M∈C 4×8

[0099] The theoretical antenna coupling matrix of the simultaneous transmit and receive array was obtained through HFSS simulation.

[0100] In a further embodiment, the amplitude and phase error of the transmit-receive array includes the transmit amplitude and phase error Γ. t and received amplitude and phase error Γ r Among them, the emission amplitude and phase error Γ tFor simultaneous transmission and reception, the propagation coefficient from the digital-to-analog converter to the antenna in the transmit link, the received amplitude, and the phase error Γ are calculated when the transmit link gain and beamforming weight of the array are equal. r The propagation coefficient from the analog-to-digital converter to the antenna end of the receiving link when the receive link gain and beamforming weight of the array are equal during simultaneous transmission and reception.

[0101] In this embodiment, the number of transmit and receive links J = 8 and K = 4. Therefore, the transmit and receive amplitude and phase errors of the array during simultaneous transmission and reception are column vectors of length 8 and 4, respectively.

[0102] Γ t ∈C 8×1

[0103] Γ r ∈C 4×1

[0104] In a further embodiment, the measurement and storage of the amplitude and phase error of the transmit and receive array of the simultaneous transmit and receive array includes:

[0105] The amplitude and phase errors of the transmit and receive arrays are obtained and stored by measuring with a vector network analyzer or by near-field measurement.

[0106] In a further embodiment, the present invention also defines a transceiver system mutual coupling matrix for a simultaneous transceiver array. Used to distinguish it from the inter-antenna coupling matrix, and the transceiver system mutual coupling matrix of the simultaneous transmit and receive array. Defined as the coupling matrix between the transmitting DAC and the receiving ADC of a simultaneous transmit / receive array; the mutual coupling matrix of the transmit / receive system of the simultaneous transmit / receive array is a complex matrix of 4 rows and 8 columns, i.e.

[0107]

[0108] Where, diag(·) is a function that transforms a vector into a diagonal matrix, and H represents the conjugate transpose of the matrix;

[0109] In this embodiment, the entire radio frequency system is used to measure the coupling matrix, so a system-level coupling matrix is ​​defined. This describes the difference between the coupling matrix measured using the radio frequency system and the required inter-antenna coupling matrix, which is affected by channel error. The system coupling matrix is ​​estimated directly using the transmitted and received signals. The inter-antenna coupling matrix, which is the final result, is obtained by subtracting the channel error from the system-level coupling matrix.

[0110] In a further embodiment, based on the theoretical antenna coupling matrix of the transmit and receive signals of the simultaneous transmit and receive array, the attenuation value required to shut down the remaining transmit channels when transmitting only a signal is determined, and the receive signal power range is determined, including:

[0111] Define the attenuation value S required for the array antenna switching filter to be turned off during simultaneous transmission and reception as the attenuation value required for a single antenna of the transmitting array to transmit alone, while the other transmitting channels are turned off.

[0112] Iterate through the different attenuation values ​​S of the array antennas during simultaneous transmission and reception;

[0113] For each attenuation value S, one transmission channel transmits, and the remaining closed transmission channels are subjected to the same attenuation value S. Monte Carlo simulation is used to simulate the effect of random phase shift on the coupling self-interference of the digital-to-analog converter at the receiving antenna when the remaining closed transmission channels have this effect.

[0114] Choose a decay value S with a smaller impact;

[0115] Confirm whether the transmit link of the array has the hardware configuration to achieve the above attenuation value, such as the power amplifier that can be controlled separately in the analog phased array, the digital attenuator, or the digital transmit baseband control board in the digital phased array.

[0116] If it exists, the range of received signal power corresponding to the attenuation value S with a smaller impact is obtained.

[0117] or,

[0118] The attenuation value S required for the antenna switching filter of the receiving array to be turned off during simultaneous transmission and reception is defined as the attenuation value required for a single antenna of the receiving array to receive alone, while the other receiving channels are turned off.

[0119] Iterate through the different attenuation values ​​S of the array antennas during simultaneous transmission and reception;

[0120] For each attenuation value S, let one transmit channel transmit, one receive channel receive, and apply the attenuation value S to the remaining closed receive channels. Use Monte Carlo simulation to simulate the effect of random phase shift in the remaining closed receive channels on the coupling self-interference of the analog-to-digital converter at the receiving antenna.

[0121] Choose a decay value S with a smaller impact;

[0122] Confirm whether the receiving link of the array has the hardware configuration to achieve the above attenuation value during transmission and reception, such as a low-noise amplifier that can be controlled individually in an analog phased array, a digitally controlled attenuator, or a digital receiving baseband control board in a digital phased array.

[0123] If it exists, the range of received signal power corresponding to the attenuation value S with a smaller impact is obtained.

[0124] In a further embodiment, Monte Carlo simulation is used to demonstrate the effect of random phase shifts in the remaining closed transmit channels on coupling self-interference at the receive antenna, including:

[0125] The relative mean square error is used to assess the impact of random phase shifts in the remaining closed transmit channels on the coupling self-interference at the receiving antenna. The relative mean square error is defined as the ratio of the mean square error of the channel estimation to the square of the amplitude of the channel estimation result.

[0126] In a further embodiment, the range of received signal power corresponding to the attenuation value S with a relatively small impact is obtained, including:

[0127]

[0128] In the formula, P kj V is the received signal power when the j-th antenna transmits alone and the k-th antenna receives alone. ref It is the reference voltage P for the analog-to-digital converter in the receive link of the array during simultaneous transmission and reception. min It is the minimum received signal power that ensures a small relative mean square error in self-interference coupled channel estimation and is unaffected by quantization error.

[0129] In a further embodiment, the transmit / receive configuration and receive gain of the simultaneous transmit / receive array are dynamically changed so that the received signal power is within the range of the received signal power, including:

[0130] The transmitting antennas of the simultaneous transmitting and receiving array transmit sequentially and individually, and the receiving antennas of the simultaneous transmitting and receiving array receive sequentially and individually.

[0131] Control the receiving gain of the array's receiving antennas to ensure that the received signal power is within the range of the received signal power;

[0132] Save the transmit signal, receive signal, and receive gain for each configuration.

[0133] In a further embodiment, controlling the receiving gain of the receiving antenna of the simultaneous transmit and receive array such that the received signal power is within the range of said received signal power includes:

[0134] Calculate the received signal power;

[0135] If the received signal power is less than the minimum received signal power, increase the receiving gain:

[0136] G kj (m+1)=G kj (m)+ΔG,P kj ≤P min

[0137] If the received signal power is greater than the maximum received signal power, reduce the receive gain:

[0138]

[0139] In the formula, m is the number of iterations for adjusting the receiving gain, and G...kj (m) is the receiving gain when the number of iterations is m, and ΔG is the adjustment step size of the receiving gain in dB;

[0140] If the received signal power is within the range of the received signal power, the loop ends, the difference between the current receiving gain and the initial receiving gain is calculated, and the transmit power difference matrix G is constructed. Δ,dB In this embodiment, G Δ,dB It is a matrix with 4 rows and 8 columns.

[0141] In a further embodiment, the coupling channel is measured for each transmit / receive configuration of the simultaneous transmit / receive array to obtain the coupling matrix:

[0142] The coupling channel is measured under each transmit / receive configuration to obtain the coupling matrix. The least squares (LS) channel estimation method or the iterative least squares (RLS) channel estimation method can be selected to estimate the transmitted and received signals for each individual transmit antenna and each individual receive antenna.

[0143] Specifically, the received signal expressions for each individually transmitting antenna and each individually receiving antenna are as follows:

[0144]

[0145] Where k' is the receiving antenna number, j' is the transmitting antenna number, k is the receiving antenna number currently used for individual reception, j is the transmitting antenna number currently used for individual transmission, and s t,j' Let be the switching filter value for the j'-th transmitting antenna. If j' = j, s t,j' =1; if j'≠j, s t,j' =S,s r,k' Let be the switching filter value for the k'-th receiving antenna. If k' = k, s r,k' =1; if k'≠k, s r,k' =S;

[0146] Specifically, using the least squares channel estimation method, the stored individual transmitted and received signals are Fourier transformed and then divided. This result is then divided by the difference in received gain and the amplitude and phase error of the transmit-receive link to obtain the self-interference channel estimate between antennas:

[0147]

[0148] In the formula, Y represents the self-interference channel between the j-th transmit antenna and the k-th receive antenna obtained using the least squares channel estimation method. kj (e jω ), X kj (e jω) represent the Fourier transforms of the received signal and the transmitted signal, respectively, and Γ represents the Fourier transform of the received signal and the transmitted signal, respectively. tj Γ represents the transmission amplitude and phase error of the j-th transmitting antenna. rk G represents the received amplitude and phase error of the k-th receiving antenna. Δ,kj The difference in receiving gain adjustment when antenna j transmits alone and antenna k receives alone, with the unit converted from dB to 1;

[0149] Construct the estimated center frequency coupling matrix between the transmit and receive array antennas:

[0150]

[0151] In the formula, The coupling matrix is ​​estimated using the least squares channel estimation method;

[0152] Using the recursive least squares channel estimation method, the saved individual transmit and receive signals are subjected to RLS adaptive filtering estimation to obtain converged weights. Then, these weights are divided by the receive gain difference and the transmit-receive link amplitude and phase error to obtain the self-interference channel estimate between antennas:

[0153]

[0154] In the formula, This represents the self-interference channel between the j-th transmit antenna and the k-th receive antenna obtained using the recursive least squares channel estimation method, where N is the filter length and w kj,i It is the i-th weight after the recursive least squares algorithm converges, i = 1, ..., N-1, Γ tj Γ represents the transmission amplitude and phase error of the j-th transmitting antenna. rk G represents the received amplitude and phase error of the k-th receiving antenna. Δ,kj The difference in receiving gain adjustment when antenna j transmits alone and antenna k receives alone, with the unit converted from dB to 1;

[0155] Construct the estimated center frequency coupling matrix between the transmit and receive array antennas:

[0156]

[0157] In the formula, This is the coupling matrix estimated using the recursive least squares channel estimation method.

[0158] This invention analyzes the minimum attenuation value of the switching filter required for individual antenna transmission to determine whether the array has the hardware conditions for self-measurement. It considers the impact of amplitude and phase errors in the transmit / receive link on the coupling matrix estimation, distinguishing between the system coupling matrix and the inter-antenna coupling matrix. It uses least-squares channel estimation and recursive least-squares channel estimation methods to estimate the self-interference coupling matrix. The impact of the number of received signal bits occupying the receive ADC on self-interference estimation is analyzed, requiring dynamic adjustment of the received power to achieve better estimation results. First, the theoretical value of the inter-antenna coupling matrix is ​​obtained using HFSS, and the amplitude and phase errors of the transmit / receive link are measured. Then, it is confirmed whether the hardware conditions meet the coupling self-measurement conditions. Next, the transmit antennas transmit sequentially, and the receive antennas receive sequentially, adaptively adjusting the received power. The self-interference channel is estimated using least-squares channel estimation or recursive least-squares channel estimation methods. After removing the effects of amplitude and phase errors and received power adjustment, the coupling matrix between the transmit and receive antennas is obtained.

[0159] Example 3

[0160] This embodiment, based on Embodiments 1 and 2, further describes how to calculate the effective isotropic isolation achieved through beamforming and digital cancellation based on the measured coupling matrix.

[0161] In the simultaneous transmit and receive array digital cancellation architecture, the effective isotropic isolation of the transmit beam is as follows:

[0162]

[0163] Effective isotropic isolation of the receiving beam is:

[0164]

[0165] Among them, P t For transmission power, G t For the transmit antenna gain, G r This represents the receiving antenna gain. t b is the transmitted beamforming vector. r For receiving the beamforming vector, q t q is the steering vector of the transmitting array. r b is the steering vector of the receiving array. t and q t It is a complex column vector of length 8, b r and q r It is a complex column vector of length 4. g t and g r These are the radiation patterns of the transmitting and receiving array elements, respectively. The system noise covariance matrix is ​​calculated using the transmit beamforming vector and the estimated coupling matrix between the center frequency points of the transmit and receive array antennas. This is the system noise covariance matrix calculated using the received beamforming vector and the estimated coupling matrix between the center frequency points of the transmit and receive array antennas. φ represents the azimuth angle in spherical coordinates; θ represents the elevation angle in spherical coordinates.

[0166] Specifically, the expression for the effective radiated power of the transmitting array is:

[0167]

[0168] The expression for the receiver array gain is:

[0169]

[0170] Optionally, the step of calculating the effective isotropic isolation achieved through beamforming and digital cancellation based on the measured coupling matrix includes:

[0171] Transmit beamforming is performed using a transmit beamforming algorithm that minimizes the maximum incident power of all receiver elements.

[0172] Receive beamforming is performed using a receive beamforming algorithm that maximizes the signal-to-interference-plus-noise ratio.

[0173] Digital cancellation is performed based on beamforming;

[0174] Calculate the effective isotropic isolation for each step.

[0175] Example 4

[0176] This embodiment demonstrates the effectiveness of the methods in embodiments 1 to 3, based on embodiments 1 to 3.

[0177] like Figure 5 As shown, the coupling error is affected by the attenuation value of the closed-channel switching filter. Figure 5 The left figure illustrates the maximum amplitude and phase error of the coupled self-interference signal at the receiving antenna compared to the ideal value when the transmitting antenna transmits alone, and the other closed transmitting channels are subjected to a given attenuation value S and a random phase shift within a certain range. The right figure illustrates the maximum amplitude and phase error of the coupled self-interference signal at the receiving ADC compared to the ideal value when the transmitting antenna transmits alone and the receiving antenna receives alone, and the other closed receiving channels are subjected to a given attenuation value S and a random phase shift within a certain range. It can be seen that the larger the attenuation value of the switching filter in the transmitting and receiving links, the smaller the coupled self-interference error. When the attenuation value is less than -50dB, the error amplitude caused by random phase shift within a 45° range is less than 1dB, and the phase shift is less than 5°.

[0178] Figure 6 The relative mean square error (RMSE) of channel estimation is affected by the number of bits the received signal occupies in the receiver ADC. It describes the relative MMS error of channel estimation after varying the received signal amplitude and passing it through an ADC with a fixed reference voltage and 8 quantization bits. Experimental results show that when the received signal is small, occupying less than 4 bits of the receiver ADC, the relative MMS error of channel estimation increases significantly due to quantization error. When the received signal occupies more than 4 bits of the receiver ADC, the relative MMS error of channel estimation is small for both methods. The RLS method is almost unaffected by the number of bits the received signal occupies in the receiver ADC, but its relative MMS error is greater than that of the LS method.

[0179] Figure 7 The magnitude and phase of the coupling matrix estimated using the LS and RLS methods. Figure 8 The magnitude and phase of the coupling matrix estimated using the LS and RLS methods are compared with the true estimation error of the coupling matrix. Experiments were conducted using Matlab's Simulink module. Figure 3 Simulated transceiver array in medium structure, using Figure 4 The coupling self-measurement scheme process was simulated. The transmitted signal was a narrowband linear frequency modulated signal with a center frequency of 9 GHz, a bandwidth of 20 MHz, and a pulse width of 1 μs. To evaluate the accuracy of the coupling matrix estimation, the coupling matrix was measured by directly extracting signals from both the transmit and receive antennas in the Simulink model. This simulated the traditional method of directly measuring the antenna-end coupling matrix using a vector network analyzer, and the resulting coupling matrix was compared with the method of this invention as the true value. The RLS algorithm filter length was 8. Experimental results show that the error of the LS method in estimating the coupling matrix approaches 0, while the elements of the coupling matrix estimated by the RLS method exhibit a uniform amplitude shift of 0.32 dB and a phase shift of 0.6°. This shift is small and does not affect the reflection of the relative value of the coupling between the transmit and receive antennas. This may be due to the limited filter length of the RLS algorithm, which reduces the computational load of channel estimation.

[0180] Figure 9To evaluate the self-interference signal power and effective isotropic isolation at different scanning angles, uniform beamforming (CBF), uniform beamforming, and baseband digital cancellation (CBF+SIC) were compared. Adaptive beamforming (ABF) and baseband digital cancellation (ABF+SIC) of the transmit / receive array were performed using the coupling matrix estimated by the ground truth, LS, and RLS methods, respectively. Experimental results show that after adaptive beamforming and digital cancellation of the transmit / receive array, an average isolation of 135 dB can be achieved, which is 46 dB higher than the average isolation of 89 dB achieved by uniform beamforming. At certain angles, a maximum isolation of 153.25 dB can be achieved. Meanwhile, the results show that the self-interference signal power and effective isotropic isolation curves of the coupling matrix estimated by the true value of the coupling matrix, LS and RLS methods respectively for transmit-receive array adaptive beamforming (ABF) and digital cancellation (ABF+SIC) are basically coincident, indicating that the coupling matrix estimated by the self-measurement scheme of the coupling matrix of the present invention is effective and can achieve the same effect in self-interference suppression as the coupling matrix obtained by the traditional measurement method.

[0181] The same or similar labels correspond to the same or similar parts;

[0182] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0183] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for self-measurement of a coupling matrix of a transceiving simultaneous array, characterized in that, The method comprises the following steps: obtaining a theoretical antenna coupling matrix of the transceiving simultaneous array through simulation; measuring and storing the amplitude and phase errors of the transmitting and receiving array of the transceiving simultaneous array; determining the attenuation value required for closing the remaining transmitting channels when transmitting a single signal according to the theoretical antenna coupling matrix of the transmitting signal and the receiving signal of the transceiving simultaneous array, and determining the receiving signal power range; dynamically changing the transceiving configuration and receiving gain of the transceiving simultaneous array so that the receiving signal power is within the receiving signal power range; measuring the coupling channel under each transceiving configuration of the transceiving simultaneous array to obtain a coupling matrix.

2. The method of claim 1, wherein, The step of obtaining the theoretical antenna coupling matrix of the transceiving simultaneous array through simulation comprises: the theoretical antenna coupling matrix of the transceiving simultaneous array is a complex matrix of JxK, wherein the element of the jth row and the kth column is defined as the propagation coefficient from the jth transmitting antenna to the kth receiving antenna, and J and K are the total number of transmitting antennas and receiving antennas respectively; the theoretical antenna coupling matrix of the transceiving simultaneous array is obtained through HFSS simulation.

3. The method of claim 2, wherein, The transmit-receive array amplitude and phase errors include transmit amplitude and phase errors and receive amplitude and phase errors wherein the transmit amplitude and phase errors are the propagation coefficients from the digital-to-analog converter to the antenna port of the transmit chain for the case that the transmit chain gain and beamforming weights of the transceiver simultaneous array are equal, the receive amplitude and phase errors are the propagation coefficients from the analog-to-digital converter to the antenna port of the receive chain for the case that the receive chain gain and beamforming weights of the transceiver simultaneous array are equal.

4. The method of claim 3, wherein, The step of measuring and storing the amplitude and phase errors of the transmitting and receiving array of the transceiving simultaneous array comprises: the amplitude and phase errors of the transmitting and receiving array of the transceiving simultaneous array are measured and stored through a vector network analyzer or near-field measurement.

5. The method of claim 4, wherein, The step of determining the attenuation value required for closing the remaining transmitting channels when transmitting a single signal according to the theoretical antenna coupling matrix of the transmitting signal and the receiving signal of the transceiving simultaneous array, and determining the receiving signal power range comprises: defining the attenuation value S of the transceiving simultaneous array antenna switch filter as the attenuation value required for closing the remaining transmitting channels when transmitting a single signal by a certain antenna of the transmitting array; iterating through different attenuation values S of the transceiving simultaneous array antenna; for each attenuation value S, letting one transmitting channel transmit and the remaining closed transmitting channels apply the attenuation value S, and using Monte Carlo simulation to simulate the influence of random phase shift of the remaining closed transmitting channels on the coupling self-interference at the digital-to-analog converter of the receiving antenna; selecting the attenuation value S with less influence; confirming whether there is a hardware configuration of the transmitting link of the transceiving simultaneous array that can reach the above attenuation value; if there is, obtaining the receiving signal power range corresponding to the attenuation value S with less influence.

6. The method of claim 5, wherein, The step of using Monte Carlo simulation to simulate the influence of random phase shift of the remaining closed transmitting channels on the coupling self-interference at the receiving antenna comprises: using the relative mean square error to evaluate the influence of random phase shift of the remaining closed transmitting channels on the coupling self-interference at the receiving antenna, wherein the relative mean square error is defined as the ratio of the channel estimation mean square error to the square of the amplitude of the channel estimation result.

7. The method of claim 6, wherein the coupling matrix self-measurement of a transceiveing array is performed by: The step of obtaining the receiving signal power range corresponding to the attenuation value S with less influence comprises: wherein, is the received signal power when the jth antenna transmits alone and the kth antenna receives alone, is the reference voltage of the analog-to-digital converter of the receive chain in the simultaneous transmit-receive array, is the minimum received signal power that guarantees a small relative mean square error in the self-interference coupling channel estimation, which is not affected by the quantization error.

8. The method of claim 7, wherein, dynamically changing the transceiving configuration and receiving gain of the transceiving simultaneous array so that the receiving signal power is within the receiving signal power range, comprising: controlling the transmitting antennas of the transceiving simultaneous array to transmit individually in turn, and controlling the receiving antennas of the transceiving simultaneous array to receive individually in turn; controlling the receiving gain of the receiving antennas of the transceiving simultaneous array so that the receiving signal power is within the receiving signal power range; saving the transmitting signal, the receiving signal and the receiving gain under each configuration.

9. The method of claim 8, wherein, controlling the reception gain of the receiving antennas of the transceiving simultaneous array so that the received signal power is within the range of the received signal power, comprising: calculating the received signal power; if the received signal power is less than the minimum received signal power, increasing the reception gain: if the received signal power is greater than the maximum received signal power, decreasing the reception gain: In the formula, m is the iteration number of adjusting the receiving gain, is the receiving gain when the iteration number is m, is the adjustment step of the receiving gain, in dB. If the received signal power is within the range of the received signal power, the loop is ended, the difference between the received gain at this time and the initial received gain is calculated, and a difference matrix of the transmission power is constructed .

10. The method of claim 9, wherein the coupling matrix self-measurement of a transceiving array is performed by: measuring the coupling channel under each transceiving configuration of the transceiving simultaneous array to obtain a coupling matrix: using a least square channel estimation method, the self-interference channel estimation between the antennas is: wherein denotes the self-interference channel estimate between the jth transmit antenna and the kth receive antenna obtained by the least square channel estimation method, denote the Fourier transform of the received signal and the transmit signal, respectively, denotes the transmit amplitude and phase error of the jth transmit antenna, denotes the receive amplitude and phase error of the kth receive antenna, is the receive gain adjustment difference value when antenna j transmits alone and antenna k receives alone, unit is converted from dB to 1;​ constructing the estimated coupling matrix: In the formula, is a coupling matrix estimated using a least square channel estimation method; using a recursive least square channel estimation method, the self-interference channel estimation between the antennas is: wherein, represents the self-interference channel estimation between the jth transmit antenna and the kth receive antenna obtained by using the recursive least square channel estimation method, N is the filter length, is the weight after the recursive least square algorithm converges, represents the transmit amplitude and phase error of the jth transmit antenna, represents the receive amplitude and phase error of the kth receive antenna, is the receive gain adjustment difference value when the antenna j transmits alone and the antenna k receives alone, the unit is converted from dB to 1;​​ constructing the estimated coupling matrix: In the formula, is a coupling matrix estimated using a recursive least square channel estimation method.

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