CN115801086A - Two-dimensional beam alignment method based on orbital angular momentum - Google Patents
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Abstract
The invention discloses a two-dimensional wave beam alignment method based on orbital angular momentum, which is suitable for the application field of vortex waves carrying orbital angular momentum. Firstly, estimating an azimuth angle based on the superimposed vortex waves; then, estimating a pitch angle based on the modal amplitude ratio of the vortex waves; calculating array position parameters through the estimated azimuth angle and the estimated pitch angle; calculating to obtain a two-dimensional beam alignment vector through the array position parameters; beam alignment is achieved based on the alignment vectors. The invention can reduce the symbol crosstalk between modes and compensate the attenuation of intrinsic mode, so that the communication capacity of a non-aligned system is closer to that of an aligned system.
Description
Technical Field
The invention relates to the field of vortex wave application carrying Orbital Angular Momentum (OAM), in particular to a two-dimensional wave beam alignment method based on Orbital Angular Momentum.
Background
Vortex waves carrying orbital angular momentum have the characteristics of annular intensity distribution and spiral phase distribution, and are proved to be capable of multiplexing infinite OAM modes at the same frequency band and the same time, namely, the vortex waves carrying different OAM modes have orthogonality, a brand new degree of freedom is provided for a multiplexing communication technology, and therefore OAM multiplexing communication has great potential in improving frequency spectrum efficiency and improving transmission capacity of a system. However, the transverse offset and the angular offset of the transmitting end and the receiving end in the OAM communication system may cause the received vortex waves to be severely distorted, resulting in inter-modal crosstalk. Aiming at the spatial correlation of OAM multiplexing communication under a non-aligned channel, beam alignment is realized by utilizing the estimated receiving and transmitting array position parameter information, and the cross talk elimination between modes under the non-aligned channel can be realized by a low-complexity system. Under the condition of simultaneous lateral deviation and angular deviation, the performance of a one-dimensional beam alignment algorithm is deteriorated, so that a two-dimensional beam alignment method with better performance under the same condition is urgently needed.
Disclosure of Invention
Aiming at the problem of crosstalk between modes of OAM communication under a non-aligned channel, the invention provides a two-dimensional beam alignment method based on orbital angular momentum, which has the following specific technical scheme:
a two-dimensional beam alignment method based on orbital angular momentum comprises the following steps:
s1: the transmitting end generates a pair of vortex waves with the same OAM modal size but opposite signs, the two vortex waves are overlapped to generate an overlapped vortex wave with uniform rotation intensity distribution along with time by utilizing the frequency difference of the two vortex waves, and azimuth angle estimation is carried out on the basis of the overlapped vortex wave;
s2: on the receiving end, based on the inter-modal amplitude of vortex waves, obtaining OAM modal energy according to a first Bessel function formula; carrying out proportional normalization on the OAM modal energy to construct an OAM modal energy proportional normalization dictionary; matching the actual OAM modal energy proportion normalization sequence received by the receiving end in an OAM modal energy proportion normalization dictionary to obtain an estimation value of a pitch angle;
s3: calculating position parameters of the uniform circular array through the azimuth angle and the pitch angle estimated in the S1 and the S2, wherein the position parameters comprise the transverse offset and the angle offset of the uniform circular array;
s4: calculating the phase modulation angle of each transmitting or receiving array element through the array position parameters estimated in the S3 to obtain a two-dimensional beam alignment vector;
s5: and creating a beam alignment matrix through the two-dimensional beam alignment vector obtained in the S4, realizing beam alignment, and converting the non-aligned channel into an equivalent aligned channel.
Further, S1 specifically is:
s101: the transmitting end generates a pair of vortex waves of OAM modes l and-l with the same size and opposite signs, the two modes bear the same signs, after the two vortex waves are superposed, the intensity of the two vortex waves is divided into two symmetrical lobes, and the signal intensity of a narrow region in the middle is almost zero; the transmitting antenna of the transmitting end is a uniform circular array, M array elements are uniformly distributed on a circle with a certain radius, all the array elements form a transmitting plane, each array element sequentially shifts the phase of a transmitting signal by 2 pi l/M around the array, and l is an OAM mode, so that vortex waves with the phase changed to 2 pi l around the transmission shaft are generated; the superposed vortex waves are superposed waves generated by superposing vortex waves in different OAM modes, and are obtained by adding emission waveforms on each array element required by the vortex waves in the different OAM modes;
s102: enabling the frequency difference of two vortex waves of a mode l and a mode-l generated by a transmitting end to be delta f, and enabling the intensity distribution of the superposed vortex waves to rotate at a constant speed along with time;
s103: the received signal of each receiving array element in the receiving plane passes through a low-pass filter and is compared with a sine signal
Performing correlation to obtain the initial phase of the low-frequency real sinusoidal signal
Combined use of initial phase
Dividing by the transmitted vortex wave mode l to calculate the azimuth angle of the receiving array element
Further, the S2 specifically is:
s201: a transmitting terminal sequentially transmits a series of CW symbols modulated on a single OAM mode;
s202: demultiplexing the received signal to obtain symbol matrix Y in each mode, and conjugate transposing Y with Y H Multiplying and taking diagonal elements to obtain a modal energy sequence
To pair
Carrying out proportion normalization by taking the lowest-order OAM mode as a standard;
s203: at a receiving end, a receiving antenna is also a uniform circular array, an OAM modal energy proportional normalization dictionary p which is also subjected to proportional normalization by taking the lowest-order OAM modal as a standard is constructed according to a first class Bessel function formula, and a proportional normalization sequence with the actual OAM modal energy is found out by utilizing a table look-up method or a matching method
And the closest term is used for obtaining an estimated value of a pitch angle alpha of the position of the field point.
Further, the S3 specifically is:
s301: calculating the abscissa of the nth receiving array element
Ordinate of the product
And the abscissa of the center of the circular array
And ordinate
Wherein the content of the first and second substances,
for the azimuth of the nth receiving array element,
the pitch angle of the nth receiving array element; n is the number of array elements of the receiving end;
s302: in a space rectangular coordinate system, the origin of coordinates is positioned at the center of the array, the Z axis is vertical to the emission plane, the positive direction is positioned at one side of the radiation direction of the vortex wave, and the estimated angular offsets of the array rotating along the Y axis and the X axis are respectively
And
wherein R is r Is the radius of the receiving circular array.
Further, the S4 specifically is:
s401: respectively calculating an azimuth angle delta alpha of an equivalent rotating shaft of the transmitting array and an azimuth angle delta theta of the equivalent rotating shaft of the receiving array returning to a parallel state:
s402: respectively calculating the phase modulation angle W of the mth transmitting array element m Phase modulation angle W 'of n-th receiving array element' n ：
Wherein R is t Is the radius of the transmitting circular array; λ is the wavelength of the signal;
s403: respectively calculating a transmitting end beam alignment vector a and a receiving end beam alignment vector b:
further, the S5 specifically is:
s501: respectively creating a transmitting end beam alignment matrix A and a receiving end beam alignment matrix B by taking a transmitting end beam alignment vector a and a receiving end beam alignment vector B as diagonal elements, wherein A = diag { a }, and B = diag { B };
s502: through the transmitting end beam alignment matrix A and the receiving end beam alignment matrix B, the symbol matrix Y on each mode is changed from the original one
Become into
Where H' is a non-aligned channel, F Q In order to multiplex the matrices, the first and second,
is F Q The conjugate transpose matrix of (a); s is a transmitting signal matrix, and z is a noise matrix; b T Is the transposition of B; equivalent noise
Is still Gaussian white noise, equivalent channel matrix B T H' a, similar to the aligned channels, achieves beam alignment, converting non-aligned channels to equivalent aligned channels.
The invention has the following beneficial effects:
(1) The azimuth information contained in the orbital angular momentum of the vortex wave is fully utilized, and the angle estimation method based on the modal amplitude comparison of the superimposed vortex wave and the vortex wave is designed through the unique intensity phase distribution characteristic of the vortex wave, so that the azimuth angle and the pitch angle of the target can be conveniently and quickly estimated; meanwhile, the influence of the direction and the angle of the angle deviation and the transverse deviation on the system is considered, the non-aligned channel is converted into an equivalent aligned channel through the phase modulation of the wave beam on the transceiving array, the inter-modal symbol crosstalk can be reduced, the intrinsic modal attenuation can be compensated, and the communication capacity of the non-aligned system is closer to the communication capacity of the aligned system.
(2) The two-dimensional beam alignment method based on the orbital angular momentum expands the application potential of the orbital angular momentum, estimates the position parameter information of the receiving and transmitting array by utilizing the spatial correlation of OAM multiplexing communication under a non-aligned channel, realizes two-dimensional beam alignment, and realizes the elimination of the inter-modal crosstalk under the non-aligned channel by using a low-complexity system.
Drawings
FIG. 1 is a top-level flow diagram of the process of the present invention.
Fig. 2 is a block diagram of the system of the present invention.
FIG. 3 is a schematic illustration of the intensity and phase distribution of a vortex wave; wherein, the upper graph in the graph (a) is the intensity distribution when the OAM mode is 0, and the lower graph is the phase distribution when the OAM mode is 0; the upper graph in the graph (b) is the intensity distribution when the OAM mode is-3, and the lower graph is the phase distribution when the OAM mode is-3; the upper graph in the graph (c) is the intensity distribution when the OAM mode is-1, and the lower graph is the phase distribution when the OAM mode is-1; in the graph (d), the upper graph shows the intensity distribution when the OAM mode is 1, and the lower graph shows the phase distribution when the OAM mode is 1; the upper graph in the graph (e) is an intensity distribution when the OAM mode is 4, and the lower graph is a phase distribution when the OAM mode is 4.
Fig. 4 is a schematic diagram of a cylindrical coordinate system established based on the transmit array.
Fig. 5 is a schematic diagram of the intensity and phase distribution of two OAM mode stacks of opposite sign; wherein, the upper left graph is an intensity distribution graph of the superimposed vortex wave, and the upper right graph is a partial enlarged graph of the intensity distribution graph; the lower left graph is a phase profile of the superimposed vortex wave, and the lower right graph is a partial enlarged view of the phase profile.
Fig. 6 is a schematic diagram of two-dimensional beam alignment of a transmit receive array in a non-aligned channel.
Detailed Description
The invention is further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.
A two-dimensional beam alignment method based on orbital angular momentum, which is mainly shown in a flowchart of the two-dimensional beam alignment method based on orbital angular momentum shown in fig. 1, and the specific steps are implemented based on a system block diagram of the two-dimensional beam alignment method based on orbital angular momentum shown in fig. 2 as follows:
s1: the transmitting end generates a pair of vortex waves with the same OAM mode size but opposite signs, the two vortex waves are overlapped to generate overlapped vortex waves with intensity distribution rotating at a constant speed along with time by using the frequency difference of the two vortex waves, and azimuth angle estimation is carried out based on the overlapped vortex waves.
The specific embodiment of S1 is as follows:
first, the radius is defined as R t The uniform circular array with the array element number of M is used as a transmitting end, and the radius is R r The uniform circular array with N array elements is used as a transmitting end, and the uniform circular array is an antenna arrangement mode for generating waves carrying orbital angular momentum, in particular to a uniform arrangement of the array elementsThe array elements are distributed on a circle with a certain radius, and all the array elements form an emission plane.
The digital phase shift network can provide different phase shifts for input signals, and in the invention, the digital phase shift network copies the input signals to generate M paths of signals, sequentially shifts the phase by 2 pi l/M, and outputs vortex wave signals with the OAM mode of l; and copying the input signal to generate M paths of signals, sequentially phase-shifting the signals by-2 pi/L/M, and outputting a vortex wave signal with-L OAM mode.
As shown in fig. 3, the intensity of the vortex wave in the cross section of the propagation axis is distributed annularly, and the phase is distributed spirally, so that the vortex wave has better spatial orientation resolution compared with the plane wave. As shown in FIG. 4, a cylindrical coordinate system is established with the coordinates of a point P in the field as
Assuming that a total number of OAM modes multiplexed is Q,
represents the set of all available OAM modalities, in modality l q The vortex wave of (A) carries a signal of
The signal received at this point may be represented as
Wherein, beta represents the fading coefficient of the sound signal when propagating underwater, and is a constant term, k is wave number, k =2 pi/lambda, r is the position vector of point P, and r is n Is the position vector of the n-th array element, l is the OAM mode, phi n Is the azimuth of the nth array element, J l (. Cndot.) is a Bessel function of order l. Using approximation of | r-r in magnitude m L ≈ r, with approximation in phase
The amplitude and phase distribution of the superposed different OAM modes may also change. When the same symbol s is carried on a pair of modes l and-l of opposite sign, equation (1) can be rewritten as
When the order l is an integer, the phase factors are combined according to the Euler formula, having
It can be seen from equation (3) that when a pair of opposite-sign modes carry the same sign, the received sign strength is subjected to a sine factor
The value of the sine factor is related to the attitude and the mode i. The intensity distribution and the phase distribution of the superimposed l = ± 1 vortex waves are shown in fig. 5, the intensity of the vortex waves is divided into two symmetrical lobes, the signal intensity of a narrow region in the middle is almost zero, the signal phases on two sides of the narrow region are distributed in a ring shape, and the phase inversion occurs at the ring-shaped connection position.
If such superimposed vortex waves are made to rotate at a fixed angular velocity, the signal received by a single array element will be a signal modulated by a low-frequency real sine signal, and the calculation of the initial phase of the low-frequency real sine signal enables the calculation of the attitude of the position of the single antenna. The frequency difference of two vortex waves of a mode l and a mode-l generated by a transmitting end is delta f, so that the intensity distribution of the superposed vortex waves rotates at a constant speed along with time, and the formula (3) can be rewritten into
At this time, the azimuth angle of the array element is only identical with the low-frequency real signal
Is correlated. By passing the received signal of each receiving array element in the receiving plane through a low-pass filter and mixing with the sinusoidal signal
Performing correlation to obtain the initial phase of the low-frequency real sinusoidal signal
Knowing the transmitting vortex wave mode l, the azimuth angle estimated value of the receiving array element can be calculated
S2: at a receiving end, obtaining OAM modal energy according to a first Bessel function formula based on the modal amplitude of vortex waves; carrying out proportional normalization on the OAM modal energy to construct an OAM modal energy proportional normalization dictionary; and matching the actual OAM modal energy proportion normalization sequence received by the receiving end in an OAM modal energy proportion normalization dictionary to obtain an estimation value of the pitch angle.
The specific implementation of S2 is as follows:
based on the vortex wave sound field formula shown in the formula (1), the space pitch angle of one point in the field is only related to the amplitude value of the vortex wave and is not related to the space azimuth angle, the longitudinal section intensity distribution obeys the Bessel function of the first type, the longitudinal section intensity distribution in the radiation direction of the vortex waves in different modes is determined, and when the energy of a transmission signal is fixed, the higher the order number of the OAM mode is, the lower the intensity of the vortex wave is. Under far field assumption, R r D, the pitch angle of the array element is not more than the pitch angle of the array element
Within this range, the amplitude ratios of the different modal signals received at the same point are in a certain relationship.
Therefore, an OAM modal energy ratio normalization dictionary can be constructed according to the Bessel function formula of the first type, and the pitch angle of the position of the field point can be obtained by finding out the item closest to the actual OAM modal energy ratio normalization sequence by using a table look-up method or a matching method.
Firstly, the transmitting end sequentially transmits a series of Continuous Wave (CW) symbols modulated on a single mode, which can enable the transmitting end to transmit a sequence of CW symbols
The positioning symbol matrix S and the receiving signal R transmitted by the baseband are
S＝diag{1，1，...，1} (5)
Demultiplexing the received signal R to obtain a symbol matrix Y on each mode
Where H denotes a non-aligned channel matrix and z denotes an additive white gaussian noise vector. The diagonal element in Y is the amplitude of single mode, in order to eliminate the interference of symbol phase and obtain the modal energy sequence
For is to
When the proportional normalization is performed, the noise energy ratio is higher in consideration of lower signal-to-noise ratio and higher noise energy ratio in the high-order mode, and in order to reduce the influence of noise, the proportional normalization is performed by taking the lowest-order mode as a standard. Normalizing word for OAM modal energy ratioThe exemplary matrix is P, each row is P i Are all standard modal energy proportion normalization sequences, and the receiving modal energy proportion normalization sequence is
Matching is carried out based on the minimum mean square error criterion, and a dictionary matching pseudo spectrum is constructed
And obtaining a peak value spectrum by traversing all modal energy proportion sequences in the dictionary, wherein the position of the spectrum peak is the pitch angle estimated value alpha of the field point.
S3: and calculating the position parameters of the uniform circular array through the azimuth angle and the pitch angle estimated in the S1 and the S2, wherein the position parameters comprise the transverse offset and the angle offset of the uniform circular array.
The specific implementation of S3 is as follows:
by the angle estimation method of S1 and S2, the azimuth angle of the nth receiving array element is estimated
And a pitch angle
In the rectangular space coordinate system, the central coordinate of the non-aligned receiving circular array to be calculated is
The array is rotated along the Y-axis and X-axis by angles, respectively
And
in the far field hypothesis, D > R r The coordinate offset of the array element on the vertical axis caused by the angular offset is very small and can be ignored, because ofThe vertical coordinates of the assumed array elements are all D, and the horizontal and vertical coordinates of the nth receiving array element can be calculated as
Because the array is a uniform circular array, the center of the array is a geometric center and the array elements are evenly distributed, the coordinate of the center of the circular array is the mean value of the coordinates of all the array elements on the circular array, and the coordinate of the center of the circular array is
The array is rotated along the Y-axis and X-axis by angles, respectively
And
taking the mean to reduce the estimation error, the angular offset can be calculated as
S4: and calculating the phase modulation angle of each transmitting or receiving array element through the array position parameters estimated in the S3 to obtain a two-dimensional beam alignment vector.
The specific implementation of S4 is as follows:
offset by d along the X-axis x Offset by d along the Y axis y Let the resultant lateral offset be d and the pitch angle at the center of the receiving array be α, which satisfies
In order to change the transmitting direction of the vortex wave, the transmitting vortex wave needs to be shaped by a wave beam, and the wave beam alignment vector a at the transmitting end is
Wherein, W m Denotes the phase angle of the mth transmitting array element, M =1, 2.
In the coordinate system shown in fig. 6, the transmitted beam alignment vector a is only laterally offset d from the receiving end along the X-axis and Y-axis directions x And d y In relation, the angular offset of the receiving end does not affect the beam alignment of the transmitting end. When d is x Direction vector of array central connecting line when not zero
The projection on the XOY coordinate plane forms an included angle with the X axis
Direction vector at this time
The angle to the Z axis remains the same as α in equation (14), taking into account not only the tilt angle of the array, but also which axis the array is to be rotated about to coincide with the virtual transmit array by rotation α.
Considering the rotation axis of the emitting array to be parallel to the direction vector
Perpendicular, the rotation axis must be aligned with the direction vector
The projection on the emission plane is vertical, and the azimuth angle estimated value of the equivalent rotating shaft of the emission array is
The azimuth included angle between the mth transmitting array element and the equivalent rotating shaft of the transmitting array is
The phase modulation angle W of the mth transmitting array element m Can be expressed as
Substituting equation (17) into equation (15) can obtain the two-dimensional beam alignment vector of the transmitting array.
In order to change the maximum gain direction of the receiving array, the receiving vortex wave needs to be subjected to inverse beam forming, and the beam alignment vector b at the transmitting end is
W′ n Denotes the phase modulation angle of the nth receiving array element, N =1, 2.
Setting receiving circular array normal vector
The included angle between the projection of the X-ray diffraction grating and the XOZ plane is theta y Direction vector of
The included angle between the projection of the angle and the plane of YOZ is theta x Direction vector of
The included angle between the Z axis and the Z axis is theta, which is called the inclination angle of the array, and theta x Is the angle of rotation of the array along the Y axis, θ y The array is rotated along the X-axis by an angle, and the coordinate of the central point O' of the receiving circular array is (d) x ，d y D) the direction vector of the array central line and the direction vector of the receiving circular array normal vector can be calculated as
In which sin 2 θ＝sin 2 θx+sin 2 θ y 。
Firstly, the rotation angle θ of the receiving array is returned to the state parallel to the transmitting array, and the rotation axis of the receiving array needs to be parallel to the normal vector of the receiving array
The projection in the XOY plane is orthogonal, then the azimuthal estimate of the equivalent axis of rotation of the receiving array back to the parallel state is
Secondly, the receiving array needs to be rotated by a certain angle to coincide with the virtual receiving array. Since the virtual receive array and the virtual transmit array are parallel, and the receive array is parallel to the XOY plane, the receive array rotates the same as the transmit array, and the angle α needs to be rotated along the rotation axis with the azimuth angle Δ α. Thus phase modulation angle W 'of n-th receiving array element' n Can be expressed as
Wherein R is t Is the radius of the transmitting circular array; λ is the wavelength of the signal;
the two-dimensional beam alignment vector of the receiving array can be obtained by substituting the equation (23) into the equation (18).
S5: and creating a beam alignment matrix through the two-dimensional beam alignment vector obtained in the S4, realizing beam alignment, and converting the non-aligned channel into an equivalent aligned channel.
The specific implementation of S5 is as follows:
in order to incorporate phase modulation phases into vortex waves after multiplexing and before demultiplexing, respectively, beam alignment vectors are respectively used
For use in a multiplexing matrix F Q Post and demultiplexing matrices
Before, the signal matrix after demultiplexing in equation (7) becomes:
wherein, a and B represent a transmitting end beam alignment matrix and a receiving end beam alignment matrix, respectively, which are diagonal matrices using beam alignment vectors as diagonal elements, a = diag { a }, B = diag { B }, H' is a non-aligned channel, F Q In order to multiplex the matrices, the matrix is,
is F Q The conjugate transpose matrix of (a); s is a transmitting signal matrix, and z is a noise matrix; b is T Is the transposition of B; equivalent noise
Is still white Gaussian noise, F Q B T The feature matrix of (2) is a unit matrix, and noise cannot be amplified. Equivalent channel matrix B T H' A is similar to the alignment channel, and beam alignment is realizedThe unaligned channel is converted into an equivalent aligned channel.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and although the invention has been described in detail with reference to the foregoing examples, it will be apparent to those skilled in the art that various changes in the form and details of the embodiments may be made and equivalents may be substituted for elements thereof. All modifications, equivalents and the like which come within the spirit and principle of the invention are intended to be included within the scope of the invention.
Claims (6)
1. A two-dimensional beam alignment method based on orbital angular momentum is characterized by comprising the following steps:
s1: the transmitting end generates a pair of vortex waves with the same OAM modal size but opposite signs, the two vortex waves are overlapped to generate an overlapped vortex wave with uniform rotation intensity distribution along with time by utilizing the frequency difference of the two vortex waves, and azimuth angle estimation is carried out on the basis of the overlapped vortex wave;
s2: at a receiving end, obtaining OAM modal energy according to a first Bessel function formula based on the modal amplitude of vortex waves; carrying out proportional normalization on the OAM modal energy to construct an OAM modal energy proportional normalization dictionary; matching the actual OAM modal energy proportion normalization sequence received by the receiving end in an OAM modal energy proportion normalization dictionary to obtain an estimation value of a pitch angle;
s3: calculating position parameters of the uniform circular array through the azimuth angle and the pitch angle estimated in the S1 and the S2, wherein the position parameters comprise transverse offset and angle offset of the uniform circular array;
s4: calculating the phase modulation angle of each transmitting or receiving array element through the array position parameters estimated in the S3 to obtain a two-dimensional beam alignment vector;
s5: and creating a beam alignment matrix through the two-dimensional beam alignment vector obtained in the S4, realizing beam alignment, and converting a non-aligned channel into an equivalent aligned channel.
2. The two-dimensional beam alignment method based on orbital angular momentum of claim 1, wherein S1 is specifically:
s101: the transmitting end generates a pair of vortex waves of OAM modes l and-l with the same size and opposite signs, the two modes bear the same signs, after the two vortex waves are superposed, the intensity of the two vortex waves is divided into two symmetrical lobes, and the signal intensity of a narrow region in the middle is almost zero; the transmitting antenna of the transmitting end is a uniform circular array, M array elements are uniformly distributed on a circle with a certain radius, all the array elements form a transmitting plane, each array element sequentially shifts the phase of a transmitting signal by 2 pi l/M around the array, and l is an OAM mode, so that vortex waves with the phase changed to 2 pi l around the transmission shaft are generated; the superposed vortex waves are superposed waves generated by superposing vortex waves in different OAM modes, and are obtained by adding emission waveforms on each array element required by the vortex waves in different OAM modes;
s102: enabling the frequency difference of two vortex waves of a mode I and a mode-I generated by a transmitting end to be delta f, and enabling the intensity distribution of the superposed vortex waves to rotate at a constant speed along with time;
s103: the received signal of each receiving array element in the receiving plane passes through a low-pass filter and is compared with a sine signal
Performing correlation to obtain the initial phase of the low-frequency real sinusoidal signal
Combined use of initial phase
Dividing by the transmitted vortex wave mode l to calculate the azimuth angle of the receiving array element
3. The two-dimensional beam alignment method based on orbital angular momentum of claim 1, wherein the S2 is specifically:
s201: a transmitting terminal sequentially transmits a series of CW symbols modulated on a single OAM mode;
s202: demultiplexing the received signal to obtain symbol matrix Y in each mode, and conjugate transposing Y with Y H Multiplying and taking diagonal elements to obtain a modal energy sequence
To pair
Carrying out proportion normalization by taking the lowest-order OAM mode as a standard;
s203: at a receiving end, the receiving antenna is also a uniform circular array, an OAM modal energy proportion normalization dictionary p which is also used for carrying out proportion normalization by taking the lowest-order OAM mode as the standard is constructed according to a Bessel function formula of the first kind, and a proportion normalization sequence with the actual OAM modal energy is found out by utilizing a table look-up method or a matching method
And the closest term is used for obtaining an estimated value of a pitch angle alpha of the position where the field point is located.
4. The two-dimensional beam alignment method based on orbital angular momentum according to claim 1, wherein the S3 is specifically:
s301: calculating the abscissa of the nth receiving array element
Ordinate of the curve
And the abscissa of the center of the circular array
And ordinate
Wherein, the first and the second end of the pipe are connected with each other,
for the azimuth of the nth receiving array element,
the pitch angle of the nth receiving array element; n is the number of array elements of the receiving end;
s302: in a space rectangular coordinate system, the origin of coordinates is positioned at the center of the array, the Z axis is vertical to the emission plane, the positive direction is positioned at one side of the radiation direction of the vortex wave, and the estimated angular offsets of the array rotating along the Y axis and the X axis are respectively
And
wherein R is r Is the radius of the receiving circular array.
5. The two-dimensional beam alignment method based on orbital angular momentum of claim 1, wherein the S4 is specifically:
s401: respectively calculating an azimuth angle delta alpha of an equivalent rotating shaft of the transmitting array and an azimuth angle delta theta of the equivalent rotating shaft of the receiving array returning to a parallel state:
s402: respectively calculating the phase modulation angle W of the mth transmitting array element m Phase modulation angle W 'of n-th receiving array element' n ：
Wherein R is t Is the radius of the transmitting circular array; λ is the wavelength of the signal;
s403: respectively calculating a transmitting end beam alignment vector a and a receiving end beam alignment vector b:
6. the two-dimensional beam alignment method based on orbital angular momentum according to claim 1, wherein the S5 is specifically:
s501: respectively creating a transmitting end beam alignment matrix A and a receiving end beam alignment matrix B by taking a transmitting end beam alignment vector a and a receiving end beam alignment vector B as diagonal elements, wherein A = diag { a } and B = diag { B };
s502: through the transmitting end beam alignment matrix A and the receiving end beam alignment matrix B, the symbol matrix Y on each mode is changed from the original one
Become into
Where H' is a non-aligned channel, F Q In order to multiplex the matrices, the matrix is,
is F Q The conjugate transpose matrix of (c); s is a transmitting signal matrix, and z is a noise matrix; b T Is the transposition of B; equivalent noise
Is still Gaussian white noise, equivalent channel matrix B T H' a, similar to the aligned channels, achieves beam alignment, converting non-aligned channels to equivalent aligned channels.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108631849A (en) * | 2018-04-17 | 2018-10-09 | 西安电子科技大学 | Multi-modal multiplexing vortex electromagnetic wave generation method based on waveform diversity |
| CN109216943A (en) * | 2018-08-03 | 2019-01-15 | 西安电子科技大学 | The controllable hybrid mode vortex wave beam generation device in direction based on phase modulation |
| CN110266354A (en) * | 2019-06-12 | 2019-09-20 | 西安电子科技大学 | The signal acceptance method of orbital angular momentum wireless communication system |
| WO2019186222A1 (en) * | 2018-03-30 | 2019-10-03 | Eutelsat S A | Innovative use of the kalman filter in reception matrices for perfoming an improved estimation of telecommunication signals |
| CN113225141A (en) * | 2021-04-21 | 2021-08-06 | 南京师范大学 | Acoustic vortex communication transceiving array calibration method based on orbital angular momentum spectral decomposition |
-
2022
- 2022-11-01 CN CN202211357378.8A patent/CN115801086A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019186222A1 (en) * | 2018-03-30 | 2019-10-03 | Eutelsat S A | Innovative use of the kalman filter in reception matrices for perfoming an improved estimation of telecommunication signals |
| CN108631849A (en) * | 2018-04-17 | 2018-10-09 | 西安电子科技大学 | Multi-modal multiplexing vortex electromagnetic wave generation method based on waveform diversity |
| CN109216943A (en) * | 2018-08-03 | 2019-01-15 | 西安电子科技大学 | The controllable hybrid mode vortex wave beam generation device in direction based on phase modulation |
| CN110266354A (en) * | 2019-06-12 | 2019-09-20 | 西安电子科技大学 | The signal acceptance method of orbital angular momentum wireless communication system |
| CN113225141A (en) * | 2021-04-21 | 2021-08-06 | 南京师范大学 | Acoustic vortex communication transceiving array calibration method based on orbital angular momentum spectral decomposition |
Non-Patent Citations (2)
| Title |
|---|
| 宋启龙: "基于天线阵列的多模态OAM波束收发原理研究", 中国优秀博硕士学位论文全文数据库(硕士), 15 January 2020 (2020-01-15) * |
| 崔小舟: "无线光通信轨道角动量技术若干关键问题研究", 中国优秀博硕士学位论文全文数据库(B博士), 15 April 2021 (2021-04-15) * |
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