WO2012129850A1

WO2012129850A1 - Method for reconstructing outer mode field of multiple input multiple output antenna channels

Info

Publication number: WO2012129850A1
Application number: PCT/CN2011/075996
Authority: WO
Inventors: 彭宏利; 黄旭
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-03-30
Filing date: 2011-06-20
Publication date: 2012-10-04
Also published as: CN102723973A

Abstract

A method for reconstructing an outer mode field of multiple input multiple output (MIMO) antenna channels is provided in the present invention. In the method, a sphere, which surrounds a terminal to be measured and the MIMO antenna, is determined; the number of truncated terms of a spherical vector wave function of the determined sphere is obtained, and power point-sources are arranged on nodes of grids formed by dividing the sphere; by using the number of the truncated terms, mode fields of the spherical vector wave function of all the power point-sources are superposed, and then an equivalent mode field of the power point-sources array is constructed; and then, a reconstructed equivalent mode field is obtained by matching an actual radiation field of the MIMO antenna with the equivalent mode field. A device for reconstructing an outer mode field of MIMO antenna channels is also provided in the present invention. The invention can accurately and quickly determine the information of an outer space radiation electromagnetic field of the MIMO antenna sphere, and obtain the same equivalence efficiency for any complex MIMO antenna and less root-mean-square error, and thus has high universality.

Description

Multi-input multi-output antenna channel out-of-channel mode field reconstruction method and device

The present invention relates to a multiple input multiple output (MIMO) antenna technology, and more particularly to a MIMO antenna channel out-of-field mode field reconstruction method and apparatus. Background technique

At present, the spatial channel models used by the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project) and Winner (Wireless World Initiative New Radio) are SCM ( Spatial Channel Model ) and SCME ( Spatial Channel Model Extenion ), respectively. The parameters are obtained by statistically processing the transmission at both ends of the transceiver and its near-field scattered signal. Although this statistical processing method can theoretically support antenna elements and arrays of arbitrary topologies, due to the diversity of antenna channels and the complexity of interaction between antennas and near-field environments, transmission based on both ends of transmission and reception and its near field The SCM and SCME channel models obtained by the scatter signal statistics cannot accurately reflect the characteristics of the antenna and its near-field channel. This situation cannot meet the long-term evolution (LTE, Long Term Evolution) and the B3G (Beyond Third Generationin) wireless chain. The urgent need for accurate simulation and evaluation of road performance. For example, on the base station side, SCM and SCME only consider an idealized, unsuitable Uniform Linear Array (ULA) model, while on the terminal side, the antenna is simplified by SCM and SCME as an ideal point radiator. . The simulation and actual measurement results show that the use of ULA antenna and point radiator model to evaluate the performance of the actual multi-antenna system will lead to large deviations, especially with the point radiator model instead of the finer terminal antenna channel model. When describing system performance, it is difficult to effectively characterize the characteristics of the terminal air (OTA, Over the Air) and the terminal SAR (Specific Absorption Rate). In order to more accurately design, evaluate and test a new generation of systems such as LTE-MIMO, it is necessary to develop a sophisticated antenna channel characteristic model in SCM and SCME. However, the construction of a fine antenna channel characteristic model involves complex electromagnetic theory. Based on the inherent miniaturization and high-density characteristics of the terminal antenna, the flexibility of the spatial structure of the terminal antenna array, the randomness of the polarization characteristics of the antenna element, and its unique strong near-field coupling effect and load-pull effect characteristics are considered. It is an urgent problem to be solved to develop an efficient and universal antenna channel model and to integrate it with existing SCM and SCME models to meet the efficiency requirements and standardization requirements of communication system fine simulation. Summary of the invention

In view of this, the main object of the present invention is to provide a method and apparatus for OFDM antenna out-of-channel mode field reconstruction, which can accurately and quickly determine the radiated electromagnetic field information of the MIMO antenna out-of-plane space.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides a method for OFDM antenna out-of-channel mode field reconstruction, the method comprising: determining a spherical surface surrounding a MIMO antenna and a terminal to be tested, acquiring a number of truncated terms of a spherical vector wave function of the determined spherical surface, and in the spherical surface An excitation point source is placed on the mesh point of the segmentation;

Using the number of truncated terms, the spherical vector wave function mode fields of all excitation point sources are superimposed to construct an equivalent mode field of the excitation point source array;

The equivalent mode field is reconstructed by matching the radiation field of the actual MIMO antenna with the equivalent mode field.

In the above solution, the determining a spherical surface surrounding the MIMO antenna and the terminal to be tested is: determining that the spherical surface surrounding the MIMO antenna and the terminal to be tested is a spherical surface with a radius of R; wherein, R≥max(D ² / A, 3D, 10A ), D is the minimum spherical diameter surrounding the MIMO antenna and the terminal to be tested, and λ is the wavelength at which the MIMO antenna radiates electromagnetic waves.

In the above solution, the number of truncated items of the spherical vector wave function for obtaining the determined spherical surface is: determining the number of truncated items N required for the expansion of the spherical vector wave function according to R; wherein, N = [ ] + 10 , [] represents rounding , k = l7ll λ . In the above solution, the source of the excitation point is placed on the spherical mesh point of the spherical surface: the spherical surface is divided into a uniform spherical mesh, and three vertical vertical positions are placed at each mesh dot position. An electric fundamental oscillator and three mutually perpendicular magnetic fundamental oscillators, and the current and the magnetic current direction of the electric basic oscillator and the magnetic fundamental oscillator respectively correspond to the x, y, and z coordinate axes of the grid local rectangular coordinate system, The three electrical fundamental oscillators and the three magnetic fundamental oscillators form a source of excitation points.

In the above solution, the ball vector wave function mode field of all excitation point sources is superimposed by using the number of truncation items, and an equivalent mode field of the excitation point source array is constructed, which is: combining the spherical vector wave function translation transformation theory, and using the ball The vector wave function expands the required number of truncated items N, and the electric and magnetic radiation fields of the excitation point source are equivalently transformed from the grid local Cartesian coordinate system to the mode field of the global Cartesian coordinate system, then the ball vector of the i-th excitation point source The wave function mode field is: ( ) + ' ^y A f +« ^z + ^, ' ^z A ^, f)F _j (F)

= 3⁄4( , , , , , )

J. Where IF |> , the superscript e and m represent the electric fundamental oscillator and the magnetic fundamental oscillator respectively, the superscript x and _z represent the spatial polarization direction of the basic vibrator, /7 = 120τ; the subscript indicates the first excitation point source, a positive integer; a' ^x , ' ^y , ' ^z , ' ^x , '' ^z are electrical fundamental oscillators, magnetic fundamental oscillator complex coefficient expansion values; , A , :f, A]y, A;; ', ^^ The electrical fundamental oscillator and the magnetic fundamental oscillator are equivalently transformed from the grid local Cartesian coordinate system to the translation and rotation transformation matrix of the global Cartesian coordinate system;

( =1, 2, · --6 ) is the spherical vector function; 匪 2? ^! ^ + ) ;

S, = «, a ^ey , ' ^z , ' ^x , ' ^y , ' ^z ); Let U _fi =(A^,Aj:f,A; _: f,Aj ,A; _: ;,AJ , then = ;

j=l

The spherical vector wave function mode field of all excitation point sources is superimposed to construct the equivalent mode field of the excitation point source array ^ (?): Where L is the number of excitation point sources;

_{_¾ ϋ} = (^) _1≤≤4. , _{1 ≤} ^ ₆ , the magnitude of all excitation point sources _Χ = ₍₁ ^, ,···, υ ^τ , then

E _mod (r) = UX _y ( ).

In the above solution, the equivalent mode field is reconstructed by matching the radiation field of the actual MIMO antenna with the equivalent mode field, and the radiation field ( ) of the actual MIMO antenna and the equivalent mode field _{m are} : _d ( ) is matched to obtain the reconstruction mode field expansion coefficient model Q; according to the reconstruction mode field expansion coefficient model Q, the amplitude X of all excitation point sources is obtained; and the equivalent mode field is reconstructed according to the amplitude X of all excitation point sources. _d ( ).

The invention provides a device for reconstructing a MIMO antenna out-of-channel mode field, the device comprising: a spherical surface determining module, a truncated item number acquiring module, an excitation point source placing module, an equivalent mode field building module, and a reconstructed equivalent mode field module; among them,

a spherical determining module, configured to determine a spherical surface surrounding the MIMO antenna and the terminal to be tested; a truncating item obtaining module, configured to obtain a number of truncated items of a spherical vector wave function of the spherical surface determined by the spherical determining module;

An excitation point source placement module, configured to place an excitation point source on a mesh point of the spherical surface determined by the spherical determination module;

An equivalent mode field construction module is configured to superimpose a ball vector wave function mode field of all excitation point sources by using a number of truncated items to construct an equivalent mode field of the excitation point source array;

The reconstructed equivalent mode field module is used to reconstruct the equivalent mode field by matching the radiation field of the actual MIMO antenna with the equivalent mode field.

In the above solution, the spherical determining module is specifically configured to determine that the spherical surface surrounding the MIMO antenna and the terminal to be tested is a spherical surface with a radius of R; wherein, R≥max(D ² 1 A, 3D, \λ), D is The minimum spherical diameter surrounding the MIMO antenna and the terminal to be tested, and λ is the wavelength at which the ΜΙΜΟ antenna radiates electromagnetic waves.

In the above solution, the truncated item number obtaining module is specifically configured to determine the number of truncated items required for the expansion of the spherical vector wave function according to R; wherein, N = [ ] + 10, [] represents rounding, k 2 Ι π Ι λ. In the above solution, the excitation point source placement module is specifically configured to divide the spherical surface determined by the spherical surface determining module into a uniform hook spherical surface grid, and place three mutually perpendicular electric basic vibrators at each of the obtained mesh dot positions. And three mutually perpendicular magnetic fundamental oscillators, and the current and magnetic current directions of the electric basic oscillator and the magnetic fundamental oscillator respectively correspond to the xyz coordinate axis direction of the grid local rectangular coordinate system, the three electric basic oscillators and three A magnetic fundamental oscillator forms a source of excitation points.

In the above solution, the equivalent mode field construction module is specifically used to combine the spherical vector wave function translation transformation theory, and uses the spherical vector wave function to expand the required number of truncated items N, and the electric and magnetic radiation fields of the excitation point source are The net pattern domain Cartesian coordinate system is equivalently transformed to the mode field of the global Cartesian coordinate system, then the spherical vector wave function mode field of the i-th excitation point source is: ( ) + ' ^y A f +« ^z + ^, ' ^z A ^, f) F _j (F)

= 3⁄4( , , , , , )

J. Where | |> i?, the superscript em represents the electric fundamental oscillator and the magnetic fundamental oscillator respectively, the superscript xy, z represents the spatial polarization direction of the basic vibrator, η = 120π; the subscript indicates the first excitation point source, which is positive Integer; a' ^x , ' ^y , ' ^z a "' ^y , ' ^z is the electrical fundamental oscillator, the magnetic fundamental oscillator complex coefficient expansion value; A, Af, ; ', ^^ is the electrical fundamental oscillator and the magnetic fundamental oscillator The rectangular coordinate system of the pattern domain is equivalently transformed to the translation and rotation transformation matrix of the global Cartesian coordinate system; () ( _ / = 1,2 ··6 ) is the spherical vector wave function system; J = 2N(N + 1) ; S , = ( ' ^x a ^ey ' ^ζ , ' ^χ , ' ^y ' ^z ); Let υ _β =( _: ;,Α,ηΑ^,Α; _: ;,Α; , then J^Sfy y, Superimposing the spherical vector wave function mode field of all excitation point sources to construct the equivalent mode field of the excitation point source array

Where L is the number of excitation point sources;

Let ϋ = (ί/ ·) _1≤≤ ο _≤6 , the amplitude of all excitation point sources _χ = ^, ,···, υ ^τ , then

E _mod (r ) =

In the above solution, the reconstructed equivalent mode field module is specifically used to compare the radiation field ( ) of the actual MIMO antenna with the equivalent mode field. _d ( ) is matched to obtain the reconstruction mode field expansion coefficient model

Q; According to the reconstruction mode field expansion coefficient model Q, the amplitude X of all excitation point sources is obtained; the equivalent mode field is reconstructed according to the amplitude X of all excitation point sources. _d ( ). The present invention provides a method and apparatus for OFDM antenna out-of-channel mode field reconstruction, determining a spherical surface surrounding a MIMO antenna and a terminal to be tested (DUT), and acquiring a number of truncated items of a spherical vector wave function of the determined spherical surface, and The excitation point source is placed on the spherical mesh point of the spherical surface; the spherical vector wave function mode field of all the excitation point sources is superimposed by using the number of truncated items, and the equivalent mode field of the excitation point source array is constructed; by using the actual MIMO antenna The radiation field is matched with the equivalent mode field to reconstruct the equivalent mode field; thus, the radiation electromagnetic field information of the outer space of the MIMO antenna can be accurately and quickly determined, and the MIMO antenna of the present invention is regarded as a "black box", The specific implementation and structure of the MIMO antenna, for any complex MIMO antenna, have the same equivalent efficiency, small root mean square error, and strong versatility, which can meet the efficiency requirements and standardization requirements of the fine simulation of the communication system. DRAWINGS

1 is a schematic flow chart of a method for implementing a MIMO antenna out-of-channel mode field reconstruction according to the present invention; FIG. 2 is a schematic structural diagram of an apparatus for implementing a MIMO antenna out-of-channel mode field reconstruction according to the present invention. detailed description

The basic idea of the present invention is: determining a spherical surface surrounding the MIMO antenna and the terminal to be tested, acquiring a number of truncated terms of the spherical vector wave function of the determined spherical surface, and placing the excitation point source on the spherical mesh point of the spherically divided mesh; Using the number of truncated terms, the spherical vector wave function mode fields of all excitation point sources are superimposed to construct the equivalent mode field of the excitation point source array. The equivalent mode is reconstructed by matching the radiation field of the actual MIMO antenna with the equivalent mode field. field.

The invention will be further described in detail below with reference to the drawings and specific embodiments.

The present invention implements a method for OFDM antenna out-of-channel mode field reconstruction. As shown in FIG. 1, the method includes the following steps:

Step 101: Determine a spherical surface surrounding the MIMO antenna and the terminal to be tested.

Specifically, if the radius of the spherical surface surrounding the MIMO antenna and the terminal to be tested is R, then R should satisfy the formula (1):

R ≥ m2ix(D ² / , 3D, lO ) ( 1 ); where D is the minimum spherical diameter surrounding the MIMO antenna and the terminal to be tested, and λ is the wavelength of the electromagnetic wave radiated by the MIMO antenna;

Then, the spherical surface surrounding the MIMO antenna and the terminal to be tested is a spherical surface having a radius of R.

Step 102: Acquire a number N of truncation items required for expansion of a spherical vector wave function of the determined spherical surface. Specifically, determine the number of truncated items N and N required for expansion of the spherical vector wave function according to R in the formula (1). Shown

N = [kR] + \0 ( 2 ) where [] denotes rounding, k = 27t l λ .

Step 103: placing an excitation point source on the spherical mesh point segmented by the spherical surface;

Here, the excitation point source is composed of three mutually perpendicular electric fundamental oscillators and three mutually perpendicular The magnetic fundamental oscillator is configured, and the current and the magnetic current direction of the electric basic vibrator and the magnetic basic vibrator are consistent with the coordinate axis direction of the grid local rectangular coordinate system;

Specifically, the spherical surface is divided into a uniform spherical mesh, and three mutually perpendicular electrical fundamental oscillators and three mutually perpendicular magnetic fundamental oscillators are placed at the position of each mesh dot obtained, and the electrical fundamental oscillator and The current and magnetic current directions of the magnetic fundamental oscillator respectively correspond to the x, y, and z coordinate axes of the grid local rectangular coordinate system. The above six basic oscillators constitute an excitation point source, and the amplitude of the first excitation point source can be expressed as η' ^χ , η' ^γ , if ) and ( , i ^y , /TM' ^ζ ), wherein the superscripts ₆ and m represent the electric fundamental oscillator and the magnetic fundamental oscillator, respectively, and the superscript x, y, z represents the basic vibrator The spatial polarization direction, that is, the coordinate axis direction of the grid local Cartesian coordinate system.

Step 104: Using the number of truncated items, superimposing the spherical vector wave function mode fields of all excitation point sources to construct an equivalent mode field of the excitation point source array;

Specifically, it can be known from the electromagnetic field theory that the electric and magnetic radiation fields generated by the first excitation point source can be expressed as:

Wherein, ^X ( ) represents the electric radiation field generated by the first excitation point source in the x-axis direction; ^χ (Ρ) represents the magnetic radiation field generated by the first excitation point source in the axial direction; and y( ) represents the first excitation point; Source The electric radiation field generated in the y-axis direction; ^m 'y( ) indicates the magnetic radiation field generated by the first excitation point source in the axial direction; ' ^Z ( ) indicates the electric radiation field generated by the first excitation point source in the z-axis direction; ^z ( ) represents the magnetic radiation field generated by the first excitation point source in the z-axis direction; |F|>i?, the superscript e and m respectively represent the electric fundamental oscillator and the magnetic fundamental oscillator, and the superscript X and jz represent the basic vibrator The S-pole 4匕 direction, that is, the coordinate axis direction of the grid local Cartesian coordinate system, 77 = 120/r; the subscript indicates the first excitation point source, which is a positive integer; where /= /^1, is a pure imaginary number; a' ^x , ' ^y , ' ^z , a '' ^y , ' ^z are electric fundamental oscillators, magnetic fundamental oscillator complex coefficient expansion values, are parameters to be sought; () ( 7 = 1, 2, -6 ) is the ball vector The wave function system is a known function.

Combining the spherical vector wave function translation transformation theory, and using the spherical vector wave function to expand the required number of truncated items N, the electric and magnetic radiation fields of the excitation point source are equivalently transformed from the grid local rectangular coordinate system to the global rectangular coordinate system. Field, then the ball vector wave function mode field of the first excitation point source ( ) is shown in equation (4a).

E(F)― Y(cf' ^x A ^e ' ^x +cT' ^x A ^m : ^x + ' ^y A ^e : ^y +(f' ^y A ^m ' ^y + ' ^z A ^e : ^z +(f' ^z A ^m ' ^z )F.(7)

43⁄4K, K K)

: ¹ (4a) where, J_ = 2N(N + 1); , , , , , , ; ^z is the translation and rotation of the electrical fundamental oscillator and the magnetic fundamental oscillator from the grid local Cartesian coordinate system to the global Cartesian coordinate system The transformation matrix is determined by the spatial relative position and relative attitude of the electrical fundamental oscillator and the magnetic fundamental oscillator; = ("Γ, ^a !' ^y , ^a , ' ^x , a ' ^y , ' ^z );

, Af), then the formula (4a) can be written as the formula (4b).

The spherical vector wave function mode field of all excitation point sources is superimposed to construct an equivalent mode field of the excitation point source array ^ ( as shown in equation (4c).

among them, . For the number _t of excitation point sources, ^{U =} ( ) i ^ O _≤ 6 , and the amplitudes of all excitation point sources ^ , ..., ^ , can be written as formula (4d).

In this step, the af' ^x ' ^y ' ^z , a '' ^x a '' ^y ' ^z can be expressed as a formula

4.1a~4.1f:

I:' ^z dL (4.1e)

– I dL (4.1f) where is the effective length of the electrical fundamental oscillator and the magnetic fundamental oscillator; the subscript indicates the source of the first excitation point and is a positive integer; l = C is a pure imaginary number.

The ^ ( ) ( =1, 2, . . . 6 ) is generally expressed as:

F _l (7) = ( cos (4.2a)

Where (r,0, represents the spatial coordinate, two ΙπΙ λ, / = V^I

Step 105, the radiation field of the actual MIMO antenna and the equivalent mode field. _d ( ) is matched to obtain a reconstruction mode field expansion coefficient model Q;

Specifically, the radiation field of the actual MIMO antenna and the equivalent mode field _{m are used} . _d ( ) is matched as shown in equation (5a):

In formula (5a), it can be expressed as formula (5b):

(5b)

7=1

Let the reconstruction mode field expansion coefficient model 0 = (2 ₁ , _3⁄4 ,..., _{3⁄4 ]3} , and get the formula (5c) from equations (4d), (5a) and (5b):

E(r)=-∑ QJFJ (r) = - QFj (r) = UX . (F) ( 5c )

j=\ ⁷ / In the spatial spherical excitation point source, the number of the sample is greater than J _max /2, and the characterization parameter of the spherical vector wave function () of the corresponding excitation point source is calculated according to the actual measured value of the excitation point source of the sample, wherein J _max = 2N(N + l) , the linear irrelevant group of the obtained characterization parameters is brought into the formula (5c), and the Gaussian elimination method is used to solve the linear equations. According to Q = dish, the reconstruction mode field expansion coefficient model Q is obtained.

Step 106: Obtain the amplitude of all the excitation point sources according to the reconstruction mode field expansion coefficient model Q.

X;

Specifically, according to the orthogonal normality of the spherical wave function of the sphere, the formula (5c) can be expressed as the formula (6a),

UX = Q ( 6a)

According to the reconstruction mode field expansion coefficient model Q, the linear equations of equation (6a) can be obtained to obtain the amplitude X of all excitation point sources, as shown in equation (6b).

X = U Q ( 6b )

Step 107: reconstruct an equivalent mode field according to the amplitude X of all excitation point sources. _d (F);

Specifically, the amplitude X of all the excitation point sources obtained by the formula (6b) is substituted into the formula (4d) to regain the equivalent mode field), at this time. _d ( ) realizes the reconstruction of the original actual mode field ^ ).

In order to implement the method of the present invention, the present invention further provides an apparatus for OFDM antenna out-of-channel mode field reconstruction. As shown in FIG. 2, the apparatus includes: a spherical surface determining module 21, a truncated item number obtaining module 22, and an excitation point source placing module. 23, an equivalent mode field building module 24, a reconstructed equivalent mode field module 25; wherein

a spherical determining module 21, configured to determine a spherical surface surrounding the MIMO antenna and the terminal to be tested; a truncated item number obtaining module 22, configured to obtain a number of truncated items of a spherical vector wave function of the spherical surface determined by the spherical determining module 21;

The excitation point source placement module 23 is configured to be split by the spherical surface determined by the spherical surface determining module 21 Place the excitation point source on the grid point;

The equivalent mode field construction module 24 is configured to superimpose the spherical wave function mode field of all the excitation point sources by using the number of truncated items, and construct an equivalent mode field of the excitation point source array;

Reconstructing the equivalent mode field module 25 for reconstructing the equivalent mode field by matching the radiation field of the actual MIMO antenna with the equivalent mode field;

The spherical determining module 21 is specifically configured to determine a radius R of a spherical surface surrounding the MIMO antenna and the terminal to be tested according to the formula (1);

The truncated item number obtaining module 22 is specifically configured to determine the number of truncated items required for the expansion of the spherical vector wave function according to R, N, as shown in formula (2);

The excitation point source placing module 23 is specifically configured to divide the spherical surface determined by the spherical surface determining module 21 into a uniform hook spherical surface grid, and place three mutually perpendicular electric basic vibrators and three at each mesh mesh point position. a mutually perpendicular magnetic fundamental oscillator, and the current and magnetic current directions of the electric basic oscillator and the magnetic fundamental oscillator respectively correspond to the x, y, and z coordinate axes of the mesh station i or the Cartesian coordinate system, and the above six basic oscillators constitute For a source of excitation points, the amplitude of the source of the first excitation point can be expressed as

(7/' ^x , l ^ey , /; ' ² ) and ( Ι "' ^χ , I ^y , / ' ^ζ ), where the superscripts e and m represent the electrical fundamental oscillator and the magnetic fundamental oscillator, respectively, superscript X, Represents the direction of the interpole 4基本 of the basic vibrator, that is, the coordinate axis direction of the grid local Cartesian coordinate system;

The equivalent mode field construction module 24 is specifically configured to combine the ball vector wave function translation transformation theory, and utilize the spherical vector wave function to expand the required number of truncated items N, and the electric and magnetic radiation fields of the excitation point source are from the grid local area. The Cartesian coordinate system is equivalently transformed to the mode field of the global Cartesian coordinate system, then the spherical vector wave function mode field of the first excitation point source ( ) is shown in formula (4a); the spherical vector wave function mode field of all excitation point sources is obtained. The equivalent mode field of the excitation point source array is superimposed as shown in equation (4c).

The reconstructed equivalent mode field module 25 is specifically configured to use a radiation field of an actual MIMO antenna and an equivalent mode field. _d ( ) is matched to obtain the reconstruction mode field expansion coefficient model Q; According to the reconstruction mode field expansion coefficient model Q, the amplitude χ of all excitation point sources is obtained; the equivalent mode field is reconstructed according to the amplitude X of all excitation point sources. _d ( ).

Example 1, determining the spherical radius of the surrounding antenna by the formula (1)

Through the formula (2), the number of truncated items in the expansion of the spherical vector wave function is obtained as N=390. After the spherical mesh is divided and the excitation point source is placed on the mesh point, the equivalent mode of the excitation point source array is constructed. field. _d , will be actual

The radiation field and equivalent mode field of the MIMO antenna. _d ( ) is matched to solve the amplitude X of all excitation point sources. After the amplitude X of all excitation point sources is substituted into the formula (4d ), the equivalent mode field E _mod (r) is reconstructed from the original actual MIMO antenna. Radiation field ^ ( ).

In this example, the radiation field ^ ( ) of the actual MIMO antenna is passed through with the equivalent mode field _m . _{When d} ( ) matches, assuming that the spatial spherical angle sampling interval is Δ0 = Δ, after obtaining the reconstructed mode field expansion coefficient model Q, if the amplitude X of all excitation point sources is obtained by the orthogonality method, the equivalent of the X reconstruction is obtained. The root mean square error of the radiation field of the mode field and the actual MIMO antenna is Errl, then Errl=22.3% when Δ^ = Δ = 1Ο°, and Erlr=6.1% when Δ0 = Δ = 3°;

If the amplitude X of all excitation point sources is obtained by the matrix transformation method, the mean square error of the radiation field of the X-reconstructed equivalent mode field and the actual MIMO antenna is Err2, then when Δ0 = Δ = 1 Ο °, Err2 =0.4%, when Δ0 = Δ = 3°, Err2 = 0.23%;

It can be seen that, after obtaining the amplitude X of all the excitation point sources by the matrix transformation method, the root mean square error of the reconstructed equivalent mode field and the radiation field of the actual MIMO antenna is small.

Through the solution of the invention, the radiant electromagnetic field information of the outer space of the MIMO antenna can be accurately and quickly determined, and the MIMO antenna is regarded as a "black box", and the specific implementation and structure of the MIMO antenna are not involved, for any complex MIMO The antenna has the same equivalent efficiency, small root mean square error, and strong versatility, which can meet the efficiency requirements and standardization requirements of the fine simulation of the communication system.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for multi-input multiple-output (MIM0) antenna out-of-channel mode field reconstruction, the method comprising:

Determining a spherical surface surrounding the MIMO antenna and the terminal to be tested, obtaining a number of truncated items of the spherical vector wave function of the determined spherical surface, and placing an excitation point source on the spherical mesh point of the spherical surface;

The method according to claim 1, wherein the determining a spherical surface surrounding the MIMO antenna and the terminal to be tested is: determining that a spherical surface surrounding the MIMO antenna and the terminal to be tested is a spherical surface having a radius of R; wherein, W ≥ max(D ² / , 3D, 10 ) , D is the minimum spherical diameter surrounding the MIMO antenna and the terminal to be tested, and λ is the wavelength of the electromagnetic wave radiated by the MIMO antenna.

The method according to claim 2, wherein the number of truncated items of the spherical vector wave function of the determined spherical surface is: determining the number of truncated items N required for the expansion of the spherical vector wave function according to R; wherein, W = [ ] + 10 , [] means rounded, k = 27l l λ .

The method according to claim 3, wherein the source of the excitation point is placed on the spherical mesh point of the spherical surface: the spherical surface is divided into a uniform spherical mesh, and each of the obtained meshes is obtained. Three mutually perpendicular electrical fundamental oscillators and three mutually perpendicular magnetic fundamental oscillators are placed at the grid point position, and the current and magnetic current directions of the electrical basic oscillator and the magnetic fundamental oscillator are respectively corresponding to the x-local rectangular coordinate system. The y, z coordinate axis directions, the three electrical fundamental oscillators and the three magnetic fundamental oscillators constitute an excitation point source.

5. The method according to claim 4, wherein the using the number of truncation terms, superimposing the spherical vector wave function mode fields of all excitation point sources to construct an equivalent mode field of the excitation point source array is: combining Ball vector wave function translation transformation theory, and the use of spherical vector wave function expansion The number of truncated items N, the electric field and magnetic radiation field of the excitation point source are equivalently transformed from the grid local Cartesian coordinate system to the mode field of the global Cartesian coordinate system, then the ball vector wave function mode field of the first excitation point source ( : ( ) + ' ^y A f +« ^z + ^, ' ^z A ^, f)F _j (F)

= 3⁄4( , , , , , )

J. Where IF |> , the superscript em represents the electric fundamental oscillator and the magnetic fundamental oscillator respectively, the superscript xj _z represents the spatial polarization direction of the basic vibrator, 77 = 120/r; the subscript represents the first excitation point source, which is a positive integer ; ' ^x , a' ^y ' ^z ' ^x '' ^z is the electrical fundamental oscillator, the magnetic fundamental oscillator complex coefficient expansion value; A; A- A; , A] y ; ', ^ ^ is the electrical fundamental oscillator and the magnetic fundamental oscillator The equivalent transformation from the grid local Cartesian coordinate system to the translation and rotation transformation matrix of the global Cartesian coordinate system; () ( _ = 1,2 ··6 ) is the spherical vector wave function system; J = 2N(N + 1) ; S, = (a' ^x a ^ey ' ^z , ' ^x , ' ^y , ' ^z ); Let ^ =( , _; H , , _; ,

Superimposing the spherical vector wave function mode field of all excitation point sources to construct the equivalent mode field of the excitation point source array

Where is the number of excitation point sources;

_{_¾ ϋ} = (^) _1≤≤4. , _{1 ≤} ^ ₆ , the amplitude of all excitation point sources _X = ₍ S, S ₂ ,..., U ^T , then

E _mod (r) = UX^.( ).

6. The method according to claim 5, wherein the reconstructing the equivalent mode field by matching the radiation field of the actual MIMO antenna with the equivalent mode field is: The radiation field of the antenna) and the equivalent mode field. _d ( ) is matched to obtain the reconstruction mode field expansion coefficient model Q; according to the reconstruction mode field expansion coefficient model Q, the amplitude X of all excitation point sources is obtained; and the equivalent mode field is reconstructed according to the amplitude X of all excitation point sources. _d ( ).

7. A device for OFDM antenna out-of-channel mode field reconstruction, the device comprising: a spherical surface determining module, a truncated item number acquiring module, an excitation point source placing module, an equivalent mode field building module, and a reconstructed equivalent mode field. Module; among them,

The device according to claim 7, wherein the spherical surface determining module is specifically configured to determine that a spherical surface surrounding the MIMO antenna and the terminal to be tested is a spherical surface with a radius of R; wherein R≥max (D ² / A, 3D, 10A) , D is the minimum spherical diameter surrounding the MIMO antenna and the terminal to be tested, and λ is the wavelength at which the MIMO antenna radiates electromagnetic waves.

The apparatus according to claim 8, wherein the truncated item number obtaining module is specifically configured to determine a number N of truncation items required for the expansion of the spherical vector wave function according to R; wherein, N = [kR] + \ , [] represents rounding, k 2 2π Ι λ .

The device according to claim 9, wherein the excitation point source placement module is specifically configured to divide the spherical surface determined by the spherical surface determining module into a uniform spherical mesh, and obtain the position of each mesh dot in the obtained mesh point. Place three mutually perpendicular electrical fundamental oscillators and three mutually perpendicular magnets a basic vibrator, and the current and the magnetic current direction of the electric basic vibrator and the magnetic basic vibrator respectively correspond to the xyz coordinate axis direction of the grid local rectangular coordinate system, and the three electric basic vibrators and the three magnetic basic vibrators constitute an excitation Point source.

The apparatus according to claim 10, wherein the equivalent mode field construction module is specifically configured to combine a ball vector wave function translation transformation theory, and use a spherical vector wave function to expand a required number of truncated items N, The electric and magnetic radiation fields of the excitation point source are equivalently transformed from the grid local Cartesian coordinate system to the mode field of the global Cartesian coordinate system. Then the ball vector wave function mode field of the first excitation point source ( ) is: ( ) + ' ^y A f +« ^z + ^, ' ^z A ^, f)F _j (F)

= 3⁄4( , , , , , )

J. Where |F|>i?, the superscript em represents the electric fundamental oscillator and the magnetic fundamental oscillator respectively, the superscript xy, z represents the spatial polarization direction of the basic vibrator, 77 = 120/r; the subscript represents the first excitation point source , is a positive integer; ' ^x , a ' ^y ' ^z ' ^x '' ^z is the electric fundamental oscillator, the magnetic fundamental oscillator complex coefficient expansion value; A; A- A; , A] y ; ', ^ ^ is the electric basic oscillator And the magnetic fundamental oscillator is transformed from the grid local Cartesian coordinate system to the translation and rotation transformation matrix of the global Cartesian coordinate system; () ( _ = 1,2 ··6 ) is the spherical vector wave function system; J = 2N (N + 1) ; S, = (a' ^x a ^ey ' ^z , ' ^x , ' ^y , ' ^z ); Let ^ =( , _; H , , _; , then ( ) 3⁄4f ( ^? );

V

The spherical vector wave function mode field of all excitation point sources is superposed to construct an equivalent mode field of the excitation point source array ^(=∑^(where L is the number of excitation point sources; (^) _1≤≤4 . , _{1 ≤} ^ ₆ , the amplitude of all excitation point sources _X = ₍ S, S ₂ ,..., U ^T , then

E _mod (r) = UX^.( ).

12. The apparatus according to claim 11, wherein the reconstructed equivalent mode field module is specifically configured to use a radiation field of an actual MIMO antenna and an equivalent mode field. _d ( ) is matched to obtain the reconstruction mode field expansion coefficient model Q; according to the reconstruction mode field expansion coefficient model Q, the amplitude X of all excitation point sources is obtained; and the equivalent mode field is reconstructed according to the amplitude X of all excitation point sources