Four-dimensional over the air performance test method for dynamic scene channel

Abstract

The present disclosure discloses a four-dimensional over the air performance test method for a dynamic scene channel. By constructing a time-domain non-stationary dynamic scene channel model, and selecting over the air (OTA) probes of appropriate number, positions and power weight in a four-dimensional multi-probe anechoic chamber (4D-MPAC) test system through a probe selection algorithm, finally a 4D-MPAC dynamic channel test system for a target channel in a DUT test area is constructed, which makes a contribution to solve the current problem of OTA performance test for a time-domain non-stationary channel. The present disclosure aims to provide a four-dimensional multi-probe anechoic chamber (4D-MPAC) for the dynamic scene channel, which can effectively and accurately reproduce a target dynamic scene channel model in an anechoic chamber on the basis of reducing the cost of the test system as much as possible by constructing the dynamic scene channel model, and provide an index for judging the accuracy of constructing the dynamic scene channel model.

Claims

1. A four-dimensional over the air performance test method for a dynamic scene channel, comprising the following steps: step 1: performing dynamic scene channel modeling; step 1.1: determining the motion speed and trajectory of a device under test in a specific scene and a time T to be tested, and determining the position, transmitting power and frequency of a base station and the position, motion speed and direction of user equipment; step 1.2: discretizing the time period T to be tested into N time moments [t.sub.1, t.sub.2, . . . , t.sub.n, . . . , t.sub.N], each time moment respectively corresponding to one of positions [p.sub.t, p.sub.2, . . . , p.sub.n, . . . , p.sub.N] of the user equipment, and respectively performing channel modeling algorithm simulation on the user equipment at each time moment to obtain a spatial channel model at each time moment, comprising an azimuth angle of arrival (AOA), a zenith angle of arrival (ZOA), an azimuth angle of departure (AOD), a zenith angle of departure (ZOD), power and delay of each cluster; stipulating azimuth angle spread of arrival (ASA), zenith angle spread of arrival (ZSA), azimuth angle spread of departure (ASD), zenith angle spread of departure (ZSD), and power angular spectrum (PAS) of each cluster, so as to complete modeling of a dynamic scene cluster delay line channel; and step 1.3: correcting the obtained channel model according to the relative line-of-sight direction between the device under test and the base station at each time moment, simulating the relative position between a terminal and the base station through a three-dimensional turntable, and cooperating with the multipath component simulated by an over the air probe to achieve a dynamic effect; and step 2: constructing a dynamic scene channel model in a multi-probe anechoic chamber test system; step 2.1: by the constructed power angular spectrum of a target channel and an antenna array of the device under test, determining a target Butler beam forming power pattern B.sub.t in a multi-probe anechoic chamber sector, at the time moment of t.sub.n, B.sub.t(Ω,t.sub.n)=a.sup.H(Ω)R.sub.t(t.sub.n)a(Ω), wherein Ω=(Θ,ϕ) is a solid angle, Θ is a vertical azimuth angle, φ is a horizontal azimuth angle, a(Ω) ∈C.sup.U×1 represents an array steering vector of the device under test when a spatial angle is Ω in a far-field condition, the u.sup.th element thereof is a.sub.u(Ω)=e.sup.jkr.sup.u, and k=2π/λ[cosΘcosϕ,cosΘsinϕ,sinΘ] is a wave vector when the angle is Ω=(Θ, ϕ), wherein λ is a wavelength; r.sub.u=[x.sub.u,y.sub.u,z.sub.u] is a position vector of the u.sub.th antenna, wherein x.sub.u,y.sub.u, z.sub.u are respectively corresponding rectangular coordinates of the u.sub.th antenna in x, y and z directions; R.sub.t(t.sub.n) is a spatial correlation matrix of the target channel of the device under test of an antenna, R.sub.t(t.sub.n)=a(Ω)P.sub.t(Ω,t.sub.n)a.sup.H(Ω), wherein P.sub.t(Ω, t.sub.n) is a corresponding normalized power angular spectrum power when the spatial angle at the time moment of t.sub.n is Ω; step 2.2: according to the power angular spectrum distribution of the cluster at each time moment obtained by channel modeling, through a probe selection algorithm, selecting K activated antenna probes from a total of M antenna probes, and the selected K probes being used for simulating the dynamic scene channel model within the time period T to be tested; step 2.3: calculating a simulated Butler beam forming power pattern Be through the selected K activated probes, at the time moment of t.sub.n, B.sub.e(Ω, t.sub.n)=a.sup.H(Ω)R.sub.e(t.sub.n)a(Ω), wherein R.sub.e(t.sub.n) ∈C.sup.U×U is a spatial correlation matrix, for simulating the dynamic channel, of the device under test having U antennae in total at the time moment of t.sub.n, R.sub.e(t.sub.n)=Σ.sup.K.sub.k=1a.sub.e(Ω.sub.k)P.sub.e(Ω.sub.k,t.sub.n)a.sub.e.sup.H(Ω.sub.k), wherein Ω.sub.k is a solid angle corresponding to the kth probe, a.sub.e(Ω.sub.k) ∈C.sup.U×1 represents an array steering vector of a DUT under the setting of a multi-probe anechoic chamber when the spatial angle is Ω.sub.k in a far-field condition, and the u.sub.th element is $a_e\left({\Omega }_k\right)=\mathrm{pl}\left(d_{k,u}\right)e^{j\frac{2\pi }{\lambda }{d}_{k,u}},$ wherein d.sub.k,u represents the distance from the kth OTA probe to the u.sub.th antenna, and pl(d.sub.k,u) represents the path loss in this distance; P.sub.e(Ω.sub.k, t.sub.n) represents the normalized power of the over the air antenna probe with the spatial angle of Ω.sub.k at the time moment of t.sub.n; step 2.4: proposing a time-averaged four-dimensional power spectrum similarity percentage for the construction quality of the multi-probe anechoic chamber dynamic channel test system in the continuous time T, namely, adding a time dimension on the basis of a static three-dimensional PSP, and the calculation method being as follows: $4D-\mathrm{PSP}=\frac{1}{T}{\int }_T\mathrm{PSP}\left(t\right)\mathrm{dt};$ $\mathrm{PSP}\left(t\right)=\frac{1}{2}\int .Math.\frac{P_r\left(\beta ,t\right)}{P_r\left({\beta }^{\prime },t\right)d{\beta }^{\prime }}-\frac{P_o\left(\beta ,t\right)}{P_o\left({\beta }^{\prime },t\right)d{\beta }^{\prime }}.Math.d\beta \times 100\%$ wherein T is the total sampling duration; 4D-PSP is the four-dimensional power spectrum similarity percentage; P.sub.o(β, t) is the target power angular spectrum calculated by using the Butler beam forming algorithm when the angle is β at the time of t; P.sub.r(β, t) is the power angular spectrum of the constructed channel calculated by using the Butler beam forming algorithm; the angle is β; the time is a t time; and the four-dimensional power spectrum similarity percentage ranges from 0 to 1; and step 2.5; judging the construction quality of the dynamic channel according to the calculation result of the four-dimensional power spectrum similarity percentage.

2. The four-dimensional over the air performance test method for the dynamic scene channel according to claim 1, wherein in step 1.2, the azimuth angle of arrival and the azimuth angle of departure of each cluster are in the range of −180° to 180°, and the zenith angle of arrival and the zenith angle of departure of each cluster are in the range of 0° to 180°.

3. The four-dimensional over the air performance test method for the dynamic scene channel according to claim 1, wherein in step 2.4, a scheme for calculating the four-dimensional power spectrum similarity percentage when discrete points are taken is: $4D-{\mathrm{PSP}}_t=\frac{1}{N}\underset{n=1}{\overset{N}{.Math.}}\mathrm{PSP}\left(t_n\right);$ wherein N is the number of sampling times at the total time moment of discretizing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a principle block diagram of a four-dimensional multi-probe anechoic chamber test system for a dynamic scene channel according to the design of the present disclosure;

(2) FIG. 2(a) is a structural schematic diagram in which position ray-tracing results at six time moments are constructed in a scene according to an embodiment of the present disclosure;

(3) FIG. 2(b) is a structural schematic diagram in which a ray-tracing result at the first time moment is constructed in a scene according to an embodiment of the present disclosure;

(4) FIG. 3(a) is a target Butler beam forming power pattern at a time moment of t1 according to an embodiment of the present disclosure;

(5) FIG. 3(b) is a simulated Butler beam forming power pattern at a time moment of t1 according to an embodiment of the present disclosure;

(6) FIG. 4(a) is a target Butler beam forming power pattern at a time moment of t2 according to an embodiment of the present disclosure;

(7) FIG. 4(b) is a simulated Butler beam forming power pattern at a time moment of t2 according to an embodiment of the present disclosure;

(8) FIG. 5(a) is a target Butler beam forming power pattern at a time moment of t3 according to an embodiment of the present disclosure;

(9) FIG. 5(b) is a simulated Butler beam forming power pattern at a time moment of t3 according to an embodiment of the present disclosure;

(10) FIG. 6(a) is a target Butler beam forming power pattern at a time moment of t4 according to an embodiment of the present disclosure;

(11) FIG. 6(b) is a simulated Butler beam forming power pattern at a time moment of t4 according to an embodiment of the present disclosure;

(12) FIG. 7(a) is a target Butler beam forming power pattern at a time moment of t5 according to an embodiment of the present disclosure;

(13) FIG. 7(b) is a simulated Butler beam forming power pattern at a time moment of t5 according to an embodiment of the present disclosure;

(14) FIG. 8(a) is a target Butler beam forming power pattern at a time moment of t6 according to an embodiment of the present disclosure; and

(15) FIG. 8(b) is a simulated Butler beam forming power pattern at a time moment of t6 according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

(16) To better know the objectives, structures, and functions of the present disclosure, a four-dimensional over the air performance test method for a dynamic scene channel of the present disclosure is further described in detail with reference to the accompanying drawings.

(17) In order to construct a mobile scene channel test system, the continuous time period to be tested needs to be discretized into multiple time moments, and channel modeling is performed at each time moment. In this operation, we need pay attention to the displacement distance between all sampling points to ensure spatial consistency. The channel modeling method can use the ray-tracing (RT) algorithm or other geometry-based stochastic channel model (GBSM) modeling algorithms to obtain the geometric channel model based on a clustered delay line (CDL) at each time moment. The line-of-sight (LOS) direction between DUT and a launch station is used as the reference direction, and by means of the rotation of the DUT on a three-dimensional turntable in the anechoic chamber and the position change of activated probes on an MPAC probe wall, the motion of the device under test is simulated, and the resulting changes in channel parameters such as angle, power, delay, and Doppler frequency are emulated. The principle block diagram of the specific test system is shown in FIG. 1.

(18) The following steps need to be completed in dynamic scene channel modeling:

(19) Step 1: the motion speed and trajectory of a device under test in a specific scene and a time T to be tested are determined, and the position, transmitting power and frequency of a base station and the position, motion speed and direction of user equipment are determined.

(20) Step 2: the time period T to be tested is discretized into N time moments [t.sub.1, t.sub.2, . . . , t.sub.n, . . . , t.sub.N], each time moment respectively corresponds to one of positions [p.sub.1, p.sub.2, . . . , p.sub.n, . . . , p.sub.N] of the user equipment, and respectively performs channel modeling algorithm simulation on the user equipment at each time moment to obtain a spatial channel model at each time moment, including an azimuth angle of arrival (AOA), a zenith angle of arrival (ZOA), an azimuth angle of departure (AOD), a zenith angle of departure (ZOD), power and delay of each cluster. Azimuth angle spread of arrival (ASA), zenith angle spread of arrival (ZSA), azimuth angle spread of departure (ASD), zenith angle spread of departure (ZSD), and power angular spectrum (PAS) of each cluster are stipulated, so as to complete modeling of a dynamic scene cluster delay line channel. The azimuth angle of arrival and the azimuth angle of departure of each cluster are in the range of −180° to 180°, and the zenith angle of arrival and the zenith angle of departure of each cluster are in the range of 0° to 180°.

(21) Step 3: the obtained channel model according to the relative line-of-sight direction between the device under test and the base station at each time moment is corrected, the relative position between a terminal and the base station through a three-dimensional turntable is simulated, and the multipath component simulated by an over the air probe to achieve a dynamic effect is cooperated with.

(22) A dynamic scene channel model in a multi-probe anechoic chamber test system is constructed by the followings:

(23) Step 1: by the constructed power angular spectrum of a target channel and an antenna array of the device under test, a target Butler beam forming power pattern B.sub.t in a multi-probe anechoic chamber sector is determined, at the time moment of t.sub.n, B.sub.t(Ω,t.sub.n)=a.sup.H(Ω)R.sub.t(t.sub.n)a(Ω), where Ω=(Θ, ϕ) is a solid angle, Θ is a vertical azimuth angle, φ is a horizontal azimuth angle, a(Ω) ∈C.sup.U×1 represents an array steering vector of the device under test when a spatial angle is Ω in a far-field condition, the u.sub.th element thereof is a(Ω) ∈C.sup.U×1, a(Ω) ∈C.sup.U×1 is a wave vector when the angle is a(Ω) ∈C.sup.U×1, where a(Ω) ∈C.sup.U×1 is a wavelength a(Ω) ∈C.sup.U×1 is a position vector of the u.sub.th antenna, where a(Ω) ∈C.sup.U×1, a(Ω) ∈C.sup.U×1 are respectively corresponding rectangular coordinates of the u.sub.th antenna in x, y and z directions a(Ω) ∈C.sup.U×1 is a spatial correlation matrix of the target channel of the device under test of an antenna, a(Ω) ∈C.sup.U×1, where a(Ω) ∈C.sup.U×1 is a corresponding normalized power angular spectrum power when the spatial angle at the time moment of t.sub.n is a(Ω) ∈C.sup.U×1.

(24) Step 2: according to the power angular spectrum distribution of the cluster at each time moment obtained by channel modeling, through a probe selection algorithm, K activated antenna probes are selected from a total of M antenna probes, and the selected K probes are used for simulating the dynamic scene channel model within the time period T to be tested.

(25) Step 3: a simulated Butler beam forming power pattern Be through the selected K activated probes is calculated, at the time moment of t.sub.n, B.sub.e(Ω,t.sub.n)=a.sup.H(Ω)R.sub.e(t.sub.n)a(Ω), where B.sub.e(Ω, t.sub.n)=a.sup.H(Ω)R.sub.e(t.sub.n)a(Ω) is a spatial correlation matrix, for simulating the dynamic channel, of the device under test having U antennae in total at the time moment of t.sub.n, R.sub.e(t.sub.n) ∈C.sup.U×U, where R.sub.e(t.sub.n) ∈C.sup.U×U is a solid angle corresponding to the kth probe, R.sub.e(t.sub.n) ∈C.sup.U×U represents an array steering vector of a DUT under the setting of a multi-probe anechoic chamber when the spatial angle is R.sub.e(t.sub.n) ∈C.sup.U×U in a far-field condition, and the u.sub.th element is, where R.sub.e(t.sub.n) ∈C.sup.U×U represents the distance from the kth OTA probe to the u.sub.th antenna, and R.sub.e(t.sub.n) ∈C.sup.U×U represents the path loss in this distance. R.sub.e(t.sub.n) ∈C.sup.U×U represents the normalized power of the over the air antenna probe with the spatial angle of R.sub.e(t.sub.n) ∈C.sup.U×U at the time moment of t.sub.n.

(26) Step 4: a concept of a time-averaged four-dimensional power spectrum similarity percentage (4D PAS Similarity Percentage, 4D-PSP) for the construction quality of the multi-probe anechoic chamber dynamic channel test system in the continuous time T is proposed, namely, a time dimension on the basis of a static three-dimensional PSP is added, and the calculation method is as follows:

(27) $4D-\mathrm{PSP}=\frac{1}{T}{\int }_T\mathrm{PSP}\left(t\right)\mathrm{dt};$$\mathrm{PSP}\left(t\right)=\frac{1}{2}\int .Math.\frac{P_r\left(\beta ,t\right)}{P_r\left({\beta }^{\prime },t\right)d{\beta }^{\prime }}-\frac{P_o\left(\beta ,t\right)}{P_o\left({\beta }^{\prime },t\right)d{\beta }^{\prime }}.Math.d\beta \times 100\%$

(28) where T is the total sampling duration. 4D-PSP is the four-dimensional power spectrum similarity percentage. P.sub.o(β,t) is the target power angular spectrum calculated by using the Butler beam forming algorithm; the angle is β; the time is a t time. P.sub.r(β,t) is the power angular spectrum of the constructed channel calculated by using the Butler beam forming algorithm when the angle is β at the time of t. The four-dimensional power spectrum similarity percentage ranges from 0 to 1.

(29) Since discrete points need to be taken during actual testing, the actual scheme for calculating 4D-PSP is as follows:

(30) $4D-{\mathrm{PSP}}_t=\frac{1}{N}\underset{n=1}{\overset{N}{.Math.}}\mathrm{PSP}\left(t_n\right);$

(31) where N is the number of sampling times at the total time moment of discretizing.

(32) Step 5: the construction quality of the dynamic channel according to the calculation result of the four-dimensional power spectrum similarity percentage is judged.

(33) The present disclosure relates to a 4D-MPAC dynamic channel test system by constructing a time-domain non-stationary dynamic scene channel model, selecting over the air (OTA) probes of appropriate numbers, positions and power weight in the 4D-MPAC test system through the probe selection algorithm, and finally constructing the target channel in a DUT test area, which makes a contribution to solve the current problem of OTA performance test for a time-domain non-stationary channel. In order to illustrate the principle and flow of the present disclosure in detail, a specific example is given below.

(34) Firstly, channel modeling is carried out by the ray-tracing algorithm, and the specific scene for simulation is given. The time to be tested is discretized into 6 time moments [t.sub.1, t.sub.2, t.sub.3, t.sub.4, t.sub.5, t.sub.6], the corresponding positions are respectively [p.sub.t, p.sub.2, p.sub.3, p.sub.4, p.sub.5, p.sub.6],the ray-tracing results of the positions at 6 time moments in the constructed urban micro cell (Urban Micro, UMi) scene are shown as in FIG. 2(a), and constructing the ray-tracing result at the first moment in the scene is shown as in FIG. 2(b). The height of the base station is set to 15 meters, the carrier frequency is set to f=28 GHz, the height of user equipment at the receiving end is set to 1 meter, and the speed is 30 km/h. Reflective materials in the scene are all set to be ideal materials, the maximum number of reflections is 2, and the ray-tracing results at 6 time moments are shown as in Table 1. In addition, the ASA of each cluster is 22°, the ZSA of each cluster is 7°, and both the horizontal and vertical PAS conform to the Laplace distribution.

(35) The ray-tracing result at each time moment in Table 1

(36) TABLE-US-00001 Azimuth Zenith Horizontal Vertical Cluster Power angle of angle of line-of-sight line-of-sight number [dB] arrival [°] arrival [°] angle [°] angle [°] t.sub.1 1 −2.1 −101.6 94.8 20.9 100.2 2 −5.6 −15.3 93.1 3 0 −2.5 96.9 4 0 −2.5 96.0 t.sub.2 1 −0.6 30.6 97.1 17.7 99.6 2 −8 −15.5 93.1 3 0 −85.6 98.7 4 0 −85.6 97.7 t.sub.3 1 −1 29.5 96.7 16.2 99.0 2 −8 −15.3 93 3 0 −82.7 81.3 4 0 −82.7 97.6 t.sub.4 1 0 27.7 96.5 14.2 98.6 2 −6.8 −15.4 92.9 t.sub.5 1 0 26.3 96.3 12.6 98.3 2 −6.8 −15.9 92.9 t.sub.6 1 0 23.9 96.1 10.3 97.9 2 −6.8 −15.8 92.8

(37) The horizontal coverage angle of the 4D-MPAC probe wall is set to −90° to 90°, the vertical coverage angle is 60° to 120°, the horizontal and vertical intervals of each probe are both 5°, so there is a total of probes of=32, the probe selection number M=(180/5-1)(60/5-1) (60/5-1)=385 is set, and it is assumed that the DUT is an array antenna of 8×8, and each single antenna is an omnidirectional antenna and perpendicular to horizontal antennae at an interval of λ/2. Correcting the channel model, subtracting the horizontal line-of-sight angle from all azimuth angles of arrival, and subtracting the vertical line-of-sight angle from all zenith angles of arrival. Then the target Butler beam forming power pattern and the simulated Butler beam forming power pattern at each time moment are shown as in FIG. 3(a), FIG. 3(b), FIG. 4(a), FIG. 4(b), FIG. 5(a), FIG. 5(b), FIG. 6(a), FIG. 6(b), FIG. 7(a), FIG. 7(b), FIG. 8(a), and FIG. 8(b), and PSP and 4D-PSP at each time moment are shown as in Table 2. It can be seen that 4D-PSP after probe selection can reach 85.85%, which has a good channel construction effect.

(38) PSP and 4D-PSP at each time moment in Table 2

(39) TABLE-US-00002 Time moment t1 t.sub.2 t.sub.3 t.sub.4 t.sub.5 t.sub.6 4D-PSP No 95.99% 92.78% 93.37% 94.01% 93.41% 92.21% 93.56% probe selection Probe 80.19% 82.52% 80.33% 90.16% 91.21% 90.70% 85.85% selection number 32

(40) It may be understood that, the present disclosure is described by using some embodiments, and a person skilled in the art learns that various changes and equivalent replacements may be made to these features and embodiments without departing from the spirit and scope of the present disclosure. In addition, in the teachings of the present disclosure, these features and embodiments may be modified to adapt specific situations and materials without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present disclosure fall within the protection scope of the present disclosure.