A full-duplex self-interference channel estimation system and method

Abstract

The present invention discloses a full-duplex self-interference channel estimation system and method. The self-interference channel estimation system includes a transmitter, a receiver, and a self-interference estimation unit. The transmitter includes a digital transmission baseband control board, a radio frequency transmission channel, a power splitter, a transmission array antenna, and multiple transmission beam channels, each of which includes a transmission beamforming unit and an amplifier. The receiver includes a reception array antenna, a combiner, a radio frequency reception channel, a digital reception baseband control board, and multiple reception beamforming channels, each of which includes a low-noise amplifier and a reception beamforming unit. The self-interference estimation unit includes a power detection module, a summing module, and a parameter control module. The present invention extracts channel statistical information by feeding back power values, and can perform channel estimation while the transmission and reception arrays are operating normally, thereby improving array operating efficiency and enabling timely response to changes in channel status.

Description

Technical Field

[0001] The present invention relates to full-duplex technology, and in particular to a full-duplex self-interference channel estimation system and method. Background Art

[0002] Full-duplex phased array systems support independent transmit and receive arrays operating simultaneously within the same spectrum, effectively improving spectrum efficiency, reducing end-to-end latency, and promoting the development of the Internet of Everything (IoE) communication network. A major challenge facing full-duplex phased array analog systems is self-interference, which couples from the transmit array to the receive array. High-power self-interference can saturate the RF front-end of adjacent receive arrays, severely impacting demodulation of the desired received signal.

[0003] Current research focuses on reducing the power of coupled self-interference by leveraging self-interference suppression techniques. As the first component of the self-interference propagation channel, spatial domain self-interference suppression can effectively reduce the self-interference power coupled to the receiving array. Adaptive beamforming can be used to suppress spatial domain self-interference. By varying the relative phase, delay, and amplitude between the transmitted signals from antenna elements, signals are transmitted in the null space of the self-interference channel. Therefore, obtaining beamforming coefficients requires prior knowledge of the self-interference channel. The self-interference channel between the transmit and receive arrays is typically considered to propagate in the near field. Existing research has mostly modeled the self-interference channel using the spherical wave channel model. However, this spherical wave model often exhibits significant discrepancies with measured results. Analog phased arrays cannot assign a distinct steering sequence to each transmit channel, making it impossible to use steering-assisted channel estimation to obtain channel state information. Consequently, obtaining accurate channel state information is difficult in large-scale analog beamforming networks. A feasible approach in engineering is to use a vector network analyzer to measure the channel between all transmit and receive element pairs. Each measurement requires opening a transmit RF channel and a receive RF channel. This process will be repeated several times, resulting in the measurement method requiring dedicated time slots and being unable to run in parallel with communication services. This is both time-consuming and inefficient. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a full-duplex self-interference channel estimation system and method. By extracting channel statistical information through feedback power values, channel estimation can be performed while the transmitting and receiving arrays are operating normally, thereby improving the array's operating efficiency and being able to respond to changes in channel status in a timely manner.

[0005] The object of the present invention is achieved through the following technical solutions: a full-duplex self-interference channel estimation system, comprising a transmitter, a receiver and a self-interference estimation unit;

[0006] The transmitter includes a digital transmission baseband control board, a radio frequency transmission channel, a power splitter, a transmission array antenna and a plurality of transmission beam channels, each of which includes a transmission beam forming unit and an amplifier;

[0007] The transmit array antenna includes K transmit antenna elements. The transmit beam channels are the same number as the transmit antenna elements and correspond one to one. The digital transmit baseband control board is used to generate a digital baseband signal, and after passing through the RF transmit channel, the signal is split into K paths by a power splitter. Each power split signal is transmitted to a transmit beam channel, where it undergoes transmit beamforming and signal amplification before being transmitted to the transmit antenna element corresponding to the transmit beam channel.

[0008] The receiver includes a receiving array antenna, a combiner, a radio frequency receiving channel, a digital receiving baseband control board, and multiple receiving beam channels, each receiving beamforming channel including a low-noise amplifier and a receiving beamforming unit. The receiving array antenna includes J receiving antenna elements, and the receiving beam channels are the same number as the receiving antenna elements and correspond one to one. The signal received by each receiving antenna element is connected to the corresponding receiving beam channel via a coupler, undergoes low-noise amplification and receiving beamforming in each receiving beam channel, is combined by the combiner, and then transmitted to the digital baseband receiving control board via the radio frequency receiving channel to complete signal reception.

[0009] The self-interference estimation unit includes a power detection module, a summing module, and a parameter control module. The input end of the power detection module is respectively connected to the coupling port of each coupler to perform power detection on the signal of each coupler coupling port. The summing module is used to sum the power detection results. The parameter control module is used to control the transmit beamforming coefficient according to the summing result and estimate the Hermitian product of the self-interference channel to obtain a self-interference channel estimation result.

[0010] Assume that after the coupling channel, the self-interference signal incident on the receiving array is expressed as:

[0011] y(t)=Hwx(t) (1)

[0012] Where x(t) represents the transmitted signal, with a mean of 0 and a variance of 1. represents the transmit beamforming coefficient, represents the self-interfering coupling channel.

[0013] The RF transmission channel includes a DAC module and an up-conversion module. The input end of the DAC module is connected to the digital transmission baseband control board, and the output end of the DAC module is connected to the power splitter through the up-conversion module.

[0014] The radio frequency receiving channel includes an ADC module and a down-conversion module. The input end of the down-conversion module is connected to the combiner, and the output end of the down-conversion module is connected to the digital receiving baseband control board through the ADC module.

[0015] A full-duplex self-interference channel estimation method comprises the following steps:

[0016] S1. Construct a solution model for the Hermitian product of the self-interference channel:

[0017] When receiving signals, the coupler connected to each receiving antenna array element couples a signal and sends it to the power detection module. The detected signal power values ​​are added in the summation module to obtain the total self-interference power coupled to the receiving array. The result is stored in the parameter control module. The total self-interference power is expressed as:

[0018] P n =w H H H Hw (2)

[0019] Assuming that the self-interference channel H is static, by changing the transmit beamforming coefficient multiple times through the parameter control module, multiple self-interference total power values ​​will be obtained, and the following formula is given:

[0020] W H H H HW=P (3)

[0021] Where P is called the power feedback matrix, and W is the matrix composed of K different transmit beamforming coefficients, which is:

[0022] W=[w1,w2,...,w K ] (4)

[0023] When W is reversible, the estimated value of M is expressed as:

[0024]

[0025] Represents the estimated value of the matrix P.

[0026] S2. Convert the solution model of the Hermitian product M of the self-interference channel into a model containing intermediate variables P0, H A and H b Computational model of

[0027] S201. Calculate the desired transmission beam pointing upward steering vector, set The azimuth angle is θ and the elevation angle is The transmit steering vector corresponding to the beam pointing direction of is calculated as follows:

[0028]

[0029] Where λ represents the operating wavelength, x A and y A Respectively represent the vectors composed of the x and y coordinates of each array element in the XOY plane;

[0030] S202. Assuming that the gain in the desired beam direction is K, we obtain:

[0031]

[0032] Decompose the transmit beamforming coefficient w into:

[0033] w=q t +q0 (8)

[0034] Among them, q t For a special solution, q0 is a zero solution, Split w into the sum of the two. The special solution part ensures the gain in the beam pointing direction, while the zero solution part is used to suppress self-interference. q0 can be further written as:

[0035] q0=Xk=k1x1+k2x2+...+k K-1 x K-1 (9)

[0036] Where k=[k1,k2,...,k K-1 ] T , represents a set of weighted coefficients, X represents the null space, which is spanned by a set of standard orthogonal bases, that is, X=span{x1,x2,...,x K-1}, let W = [q t X], obviously W is reversible;

[0037] S203. Set W = [q t Substitute X] into formula (3), and use block matrix multiplication and matrix inversion to obtain:

[0038]

[0039] in,

[0040]

[0041] H A =X H MX (12)

[0042] H b =X H Mq t (13)

[0043] Obtain The matrix needs to obtain P0, H A and H b The estimated value of ; these three variables can be regarded as intermediate variables, mainly to simplify the definition of expression.

[0044] S3. Give the calculation method of the power feedback matrix P:

[0045] The P matrix is ​​a Hermitian matrix whose diagonal elements can be expressed as:

[0046]

[0047] Where diag(·) represents the matrix diagonal elements, and its physical meaning is the total coupled self-interference power corresponding to each transmit beamforming coefficient. The element in the kth row and ith column (i≠k) of the P matrix is ​​expressed as:

[0048]

[0049] The off-diagonal elements are usually complex numbers, but the power feedback value is a positive real number and cannot be directly obtained through power feedback;

[0050]

[0051]

[0052]

[0053]

[0054] Among them, j represents the imaginary unit, real(·) represents the real part, imag(·) represents the imaginary part, and w i +w k and w i +jw k As transmit beamforming coefficients, they are assigned to the transmit array, and the real and imaginary parts of the elements in the P matrix can be obtained through power feedback.

[0055] S4. Control the change of the transmit beamforming coefficient through the parameter control module. Under different transmit beamforming coefficients, the total power of the feedback self-interference is solved and stored in the parameter control module for subsequent channel estimation calculation;

[0056] S401. Let w = q t , and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0057] S402. Let w = x k, k=1,2,...,K-1, set the cycle, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0058] S403. Let w = q t +x k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0059] S404. Let w = q t +jx k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0060] S405. Let w = q t +x i +x k , k=1,2,...,K-1,i=1,2,...,K-1,i≠k, set the loop, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0061] S406. Let w = q t +x i +jx k , k=1,2,...,K-1, i=1,2,...,K-1, i≠k, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0062] S5. The parameter control module integrates all the total power of the feedback self-interference and calculates H A and H b The estimated value H A 、H b , and combined with the estimated value of P0 Calculated That is, to obtain the estimated value of the Hermitian product of the self-interference channel;

[0063] S501.H b is a column vector, where the real and imaginary parts of the kth element are and

[0064]

[0065]

[0066] S502. Matrix H AThe real and imaginary parts of the elements in row k and column i (i≠k) are and The diagonal elements are

[0067]

[0068]

[0069] S503. Change P0, H A and H b The estimated value of is brought in and the calculation is That is, the estimated value of the Hermitian product of the self-interference channel is obtained.

[0070] The beneficial effects of the present invention are as follows: the present invention extracts channel statistical information by feeding back power values, can perform channel estimation while the transmitting and receiving arrays are operating normally, improves array operating efficiency, and can respond to changes in channel status in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 Schematic diagram of the system principle of the present invention. DETAILED DESCRIPTION

[0072] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0073] like Figure 1 As shown, a full-duplex self-interference channel estimation system includes a transmitter, a receiver and a self-interference estimation unit;

[0074] The transmitter includes a digital transmission baseband control board, a radio frequency transmission channel, a power splitter, a transmission array antenna and a plurality of transmission beam channels, each of which includes a transmission beam forming unit and an amplifier;

[0075] The transmit array antenna includes K transmit antenna elements. The transmit beam channels are the same number as the transmit antenna elements and correspond one to one. The digital transmit baseband control board is used to generate a digital baseband signal, and after passing through the RF transmit channel, the signal is split into K paths by a power splitter. Each power split signal is transmitted to a transmit beam channel, where it undergoes transmit beamforming and signal amplification before being transmitted to the transmit antenna element corresponding to the transmit beam channel.

[0076] The receiver includes a receiving array antenna, a combiner, a radio frequency receiving channel, a digital receiving baseband control board, and multiple receiving beam channels, each receiving beamforming channel including a low-noise amplifier and a receiving beamforming unit. The receiving array antenna includes J receiving antenna elements, and the receiving beam channels are the same number as the receiving antenna elements and correspond one to one. The signal received by each receiving antenna element is connected to the corresponding receiving beam channel via a coupler, undergoes low-noise amplification and receiving beamforming in each receiving beam channel, is combined by the combiner, and then transmitted to the digital baseband receiving control board via the radio frequency receiving channel to complete signal reception.

[0077] The self-interference estimation unit includes a power detection module, a summing module, and a parameter control module. The input end of the power detection module is respectively connected to the coupling port of each coupler to perform power detection on the signal of each coupler coupling port. The summing module is used to sum the power detection results. The parameter control module is used to control the transmit beamforming coefficient according to the summing result and estimate the Hermitian product of the self-interference channel to obtain a self-interference channel estimation result.

[0078] In an embodiment of the present application, each of the transmit beamforming units includes a first adjustable attenuator and a first adjustable phase shifter.

[0079] In an embodiment of the present application, each of the receive beamforming units includes a second adjustable attenuator and a second adjustable phase shifter.

[0080] In the embodiment of the present application, the signal transmission and reception process is as follows:

[0081] The digital transmit baseband control board generates the signal to be transmitted, which is then sent to the power splitter through the RF transmit channel and divided into K paths. Each power split signal is then transmitted to a transmit beam channel. After undergoing transmit beamforming and amplification in the transmit beam channel, it is transmitted to the transmit antenna array element corresponding to the transmit beam channel. The signal is then transmitted by the K transmit antenna array elements of the transmit array antenna.

[0082] The J receiving antenna elements of the receiving array antenna receive signals. The signals received by each receiving antenna element are transmitted to the corresponding receiving beam channel through a coupler. After low-noise amplification and receiving beamforming in each receiving beam channel, they are combined by a combiner and then transmitted to the digital baseband receiving control board through the RF receiving channel to complete the signal reception.

[0083] After the coupling channel, the self-interference signal of the incident receiving array is expressed as:

[0084] y(t)=Hwx(t) (20)

[0085] Where x(t) represents the transmitted signal, with a mean of 0 and a variance of 1. represents the transmit beamforming coefficient, represents the self-interfering coupling channel.

[0086] A full-duplex self-interference channel estimation method comprises the following steps:

[0087] S1. Construct a solution model for the Hermitian product of the self-interference channel:

[0088] When receiving signals, the coupler connected to each receiving antenna array element couples a signal and sends it to the power detection module. The detected signal power values ​​are added in the summation module to obtain the total self-interference power coupled to the receiving array. The result is stored in the parameter control module. The total self-interference power is expressed as:

[0089] P n =w H H H Hw (21)

[0090] Assuming that the self-interference channel H is static, by changing the transmit beamforming coefficient multiple times through the parameter control module, multiple self-interference total power values ​​will be obtained, and the following formula is given:

[0091] W H H H HW=P (22)

[0092] Where P is called the power feedback matrix, and W is the matrix composed of K different transmit beamforming coefficients, which is:

[0093] W=[w1,w2,...,w K ] (twenty three)

[0094] When W is reversible, the estimated value of M is expressed as:

[0095]

[0096] S2. Convert the solution model of the Hermitian product M of the self-interference channel into a model containing intermediate variables P0, H A and H b Computational model of

[0097] S201. Calculate the desired transmission beam pointing upward steering vector, set The azimuth angle is θ and the elevation angle is The transmit steering vector corresponding to the beam pointing direction of is calculated as follows:

[0098]

[0099] Where λ represents the operating wavelength, x A and y A Respectively represent the vectors composed of the x and y coordinates of each array element in the XOY plane;

[0100] S202. Assuming that the gain in the desired beam direction is K, we obtain:

[0101]

[0102] Decompose the transmit beamforming coefficient w into:

[0103] w=q t +q0 (27)

[0104] Among them, q t For a special solution, q0 is a zero solution, Split w into the sum of the two. The special solution part ensures the gain in the beam pointing direction, while the zero solution part is used to suppress self-interference. q0 can be further written as:

[0105] q0=Xk=k1x1+k2x2+...+k K-1 x K-1 (28)

[0106] Where k=[k1,k2,...,k K-1 ] T , represents a set of weighted coefficients, X represents the null space, which is spanned by a set of standard orthogonal bases, that is, X=span{x1,x2,...,x K-1}, let W = [q t X], obviously W is reversible;

[0107] S203. Set W = [q t Substitute X] into formula (3), and use block matrix multiplication and matrix inversion to obtain:

[0108]

[0109] in,

[0110]

[0111] H A =X H MX (31)

[0112] H b =X H Mq t (32)

[0113] Obtain The matrix needs to obtain P0, H A and Hb estimated value of;

[0114] S3. Give the calculation method of the power feedback matrix P:

[0115] The P matrix is ​​a Hermitian matrix whose diagonal elements can be expressed as:

[0116]

[0117] Where diag(·) represents the matrix diagonal elements, and its physical meaning is the total coupled self-interference power corresponding to each transmit beamforming coefficient. The element in the kth row and ith column (i≠k) of the P matrix is ​​expressed as:

[0118]

[0119] The off-diagonal elements are usually complex numbers, but the power feedback value is a positive real number and cannot be directly obtained through power feedback;

[0120]

[0121]

[0122]

[0123]

[0124] Among them, j represents the imaginary unit, real(·) represents the real part, imag(·) represents the imaginary part, and w i +w k and w i +jw k As transmit beamforming coefficients, they are assigned to the transmit array, and the real and imaginary parts of the elements in the P matrix can be obtained through power feedback.

[0125] S4. Control the change of the transmit beamforming coefficient through the parameter control module. Under different transmit beamforming coefficients, the total power of the feedback self-interference is solved and stored in the parameter control module for subsequent channel estimation calculation;

[0126] S401. Let w = q t , and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0127] S402. Let w = x k , k=1,2,...,K-1, set the cycle, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0128] S403. Let w = qt +x k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0129] S404. Let w = q t +jx k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0130] S405. Let w = q t +x i +x k , k=1,2,...,K-1,i=1,2,...,K-1,i≠k, set the loop, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0131] S406. Let w = q t +x i +jx k , k=1,2,...,K-1, i=1,2,...,K-1, i≠k, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power

[0132] S5. The parameter control module integrates all the total power of the feedback self-interference and calculates H A and H b The estimated value H A 、H b , and combined with the estimated value of P0 Calculated That is, to obtain the estimated value of the Hermitian product of the self-interference channel;

[0133] S501.H b is a column vector, where the real and imaginary parts of the kth element are and

[0134]

[0135]

[0136] S502. Matrix H A The real and imaginary parts of the elements in row k and column i (i≠k) are and The diagonal elements are

[0137]

[0138]

[0139] S503. Change P0, H A and H b The estimated value of is brought in and the calculation is That is, the estimated value of the Hermitian product of the self-interference channel is obtained.

[0140] Because q t Add any x k or x i and x k The combination of can ensure that the gain in the desired beam direction is K, so in the entire measurement process, except for the beamforming coefficients x1, x2, ..., x K After step 6, the remaining steps ensure transmit beam pointing and gain. The receive array remains open throughout the measurement, and the receive beamforming coefficients remain constant, thus ensuring receive beam pointing and gain. In summary, this method enables channel estimation while maintaining the normal operation of the transmit and receive arrays.

[0141] The foregoing description is a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present invention can be used in other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A full-duplex self-interference channel estimation system, characterized by: The self-interference channel estimation system includes a transmitter, a receiver and a self-interference estimation unit; The transmitter includes a digital transmission baseband control board, a radio frequency transmission channel, a power splitter, a transmission array antenna and a plurality of transmission beam channels, each of which includes a transmission beam forming unit and an amplifier; The transmit array antenna includes K transmit antenna elements. The transmit beam channels are the same number as the transmit antenna elements and correspond one to one. The digital transmit baseband control board is used to generate a digital baseband signal, and after passing through the RF transmit channel, the signal is split into K paths by a power splitter. Each power split signal is transmitted to a transmit beam channel, where it undergoes transmit beamforming and signal amplification before being transmitted to the transmit antenna element corresponding to the transmit beam channel. The receiver includes a receiving array antenna, a combiner, a radio frequency receiving channel, a digital receiving baseband control board, and multiple receiving beam channels, each receiving beamforming channel including a low-noise amplifier and a receiving beamforming unit. The receiving array antenna includes J receiving antenna elements, and the receiving beam channels are the same number as the receiving antenna elements and correspond one to one. The signal received by each receiving antenna element is connected to the corresponding receiving beam channel via a coupler, undergoes low-noise amplification and receiving beamforming in each receiving beam channel, is combined by the combiner, and then transmitted to the digital baseband receiving control board via the radio frequency receiving channel to complete signal reception. The self-interference estimation unit includes a power detection module, a summing module, and a parameter control module. The input end of the power detection module is respectively connected to the coupling port of each coupler to perform power detection on the signal of each coupler coupling port. The summing module is used to sum the power detection results. The parameter control module is used to control the transmit beamforming coefficient according to the summing result, and estimate the Hermitian product of the self-interference channel according to the summing result to obtain a self-interference channel estimation result.

2. A full-duplex self-interference channel estimation system according to claim 1, characterized in that: Each of the transmit beamforming units includes a first adjustable attenuator and a first adjustable phase shifter.

3. The full-duplex self-interference channel estimation system according to claim 1, wherein: Each of the receive beamforming units includes a second adjustable attenuator and a second adjustable phase shifter.

4. The full-duplex self-interference channel estimation system according to claim 1, wherein: The RF transmission channel includes a DAC module and an up-conversion module. The input end of the DAC module is connected to the digital transmission baseband control board, and the output end of the DAC module is connected to the power splitter through the up-conversion module. The radio frequency receiving channel includes an ADC module and a down-conversion module. The input end of the down-conversion module is connected to the combiner, and the output end of the down-conversion module is connected to the digital receiving baseband control board through the ADC module.

5. A full-duplex self-interference channel estimation method, based on the system according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Construct a solution model for the Hermitian product of the self-interference channel: S2. Convert the solution model of the Hermitian product M of the self-interference channel into a model containing intermediate variables P0, H A and H b computational models; S3. Give the calculation method of the power feedback matrix P: S4. Control the change of the transmit beamforming coefficient through the parameter control module. Under different transmit beamforming coefficients, the total power of the feedback self-interference is solved and stored in the parameter control module for subsequent channel estimation calculation; S5. The parameter control module integrates all the total power of the feedback self-interference and calculates H A and H b The estimated value of P0 is combined with the estimated value of Calculated That is, the estimated value of the Hermitian product of the self-interference channel is obtained.

6. The full-duplex self-interference channel estimation method according to claim 5, characterized in that: The step S1 comprises: When receiving signals, the coupler connected to each receiving antenna array element couples a signal and sends it to the power detection module. The detected signal power values ​​are superimposed in the summation module to obtain the total self-interference power coupled to the receiving array surface, and the result is stored in the parameter control module. After the coupling channel, the self-interference signal of the incident receiving array is expressed as: y(t)=Hwx(t) (1) Among them, x(t) represents the transmitted signal, with a mean of 0 and a variance of 1. represents the transmit beamforming coefficient, represents the self-interference coupling channel; The total self-interference power is expressed as: P n =w H H H Hw (2) Assuming that the self-interference channel H is static, by changing the transmit beamforming coefficient multiple times through the parameter control module, multiple self-interference total power values ​​will be obtained, and the following formula is given: W H H H HW=P (3) Where P is called the power feedback matrix, and W is the matrix composed of K different transmit beamforming coefficients, which is: W=[w1,w2,...,w K ] (4) When W is reversible, the estimated value of M is expressed as: Represents the estimated value of the matrix P.

7. The full-duplex self-interference channel estimation method according to claim 6, wherein: The step S2 comprises: S201. Calculate the desired transmission beam pointing upward steering vector, set The azimuth angle is θ and the elevation angle is The transmit steering vector corresponding to the beam pointing direction of is calculated as follows: Where λ represents the operating wavelength, x A and y A Respectively represent the vectors composed of the x and y coordinates of each array element in the XOY plane; S202. Assuming that the gain in the desired beam direction is K, we obtain: Decompose the transmit beamforming coefficient w into: w=q t +q0 (8) Among them, q t For a special solution, q0 is a zero solution, Split w into the sum of the two. The special solution part ensures the gain in the beam pointing direction, while the zero solution part is used to suppress self-interference. q0 can be further written as: q0=Xk=k1x1+k2x2+...+k K-1 x K-1 (9) Where k=[k1,k2,...,k K-1 ] T , represents a set of weighted coefficients, X represents the null space, which is composed of a set of standard orthogonal bases, that is, X=span{x1,x2,...,x K-1 }, let W = [q t X], it is obvious that W is reversible; S203. Set W = [q t Substitute X] into formula (3), and use block matrix multiplication and matrix inversion to obtain: in, H A =X H MX (12) H b =X H Mq t (13) Obtain P0, H A and H b estimated value.

8. The full-duplex self-interference channel estimation method according to claim 7, wherein: The step S3 comprises: The P matrix is ​​a Hermitian matrix whose diagonal elements are expressed as: Where diag(·) represents the matrix diagonal elements, and its physical meaning is the total coupled self-interference power corresponding to each transmit beamforming coefficient. The element in the kth row and ith column of the P matrix is ​​expressed as: Where i≠k, the off-diagonal elements are usually complex numbers, but the power feedback value is a positive real number and cannot be directly obtained through power feedback; Among them, j represents the imaginary unit, real(·) represents the real part, imag(·) represents the imaginary part, and w i +w k and w i +jw k As transmit beamforming coefficients, they are assigned to the transmit array, and the real and imaginary parts of the elements in the P matrix can be obtained through power feedback.

9. The full-duplex self-interference channel estimation method according to claim 8, characterized in that: The step S4 comprises: S401. Let w = q t , and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power S402. Let w = x k , k=1,2,...,K-1, set the cycle, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power S403. Let w = q t +x k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power S404. Let w = q t +jx k , k=1,2,...,K-1, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power S405. Let w = q t +x i +x k , k=1,2,...,K-1,i=1,2,...,K-1,i≠k, set the loop, and use w as the transmit beamforming coefficient to obtain the total feedback self-interference power S406. Let w = q t +x i +jx k , k=1,2,...,K-1, i=1,2,...,K-1, i≠k, and w is used as the transmit beamforming coefficient to obtain the total feedback self-interference power 10. The full-duplex self-interference channel estimation method according to claim 5, characterized in that: The step S5 comprises: S501.H b is a column vector, where the real and imaginary parts of the kth element are and S502. Matrix H A The real and imaginary parts of the elements in row k and column i are and The diagonal elements are S503. Set P0, H A and H b Substitute the estimated value of That is, the estimated value of the Hermitian product of the self-interference channel is obtained.

Images