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CN110620627B - Non-stationary channel modeling method and device for vehicle-to-vehicle multi-antenna system - Google Patents

Non-stationary channel modeling method and device for vehicle-to-vehicle multi-antenna system Download PDF

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CN110620627B
CN110620627B CN201910973638.6A CN201910973638A CN110620627B CN 110620627 B CN110620627 B CN 110620627B CN 201910973638 A CN201910973638 A CN 201910973638A CN 110620627 B CN110620627 B CN 110620627B
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CN110620627A (en
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马楠
王妙伊
张平
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Beijing University of Posts and Telecommunications
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    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3912—Simulation models, e.g. distribution of spectral power density or received signal strength indicator [RSSI] for a given geographic region
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/391—Modelling the propagation channel
    • H04B17/3913—Predictive models, e.g. based on neural network models
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    • H04—ELECTRIC COMMUNICATION TECHNIQUE
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    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H04W4/46—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P] for vehicle-to-vehicle communication [V2V]

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Abstract

In order to solve the problems of the prior art, the present disclosure provides a non-stationary channel modeling method and apparatus for a vehicle-to-vehicle multi-antenna system, which can build a high-precision channel model. A method of non-stationary channel modeling for a vehicle-to-vehicle multi-antenna system, comprising: establishing a double-ring model by taking the transmitting end and the receiving end as circle centers; establishing a semi-ellipsoid model by taking a transmitting end and a receiving end as focuses; obtaining a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model; obtaining a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-ray path and a double-ray path; a spatio-temporal correlation function is obtained based on a channel impulse response function. The channel model is established based on the direct path, the single-ray path and the double-ray path, the accuracy of the established model is higher, and the characteristics of the V2V MIMO channel can be well represented.

Description

Non-stationary channel modeling method and device for vehicle-to-vehicle multi-antenna system
Technical Field
The present disclosure relates to the field of communications, and in particular, to a method and an apparatus for modeling a non-stationary channel of a vehicle-to-vehicle multi-antenna system.
Background
In recent years, massive MIMO (multiple input multiple output) multiple antenna wireless communication technology has been the focus of research because of its advantage of greatly improving spectral efficiency and system capacity. Meanwhile, vehicle-to-vehicle (V2V) communication is considered one of indispensable parts of intellectualization. Therefore, it is very beneficial for the fifth generation wireless communication network (5G) to consider adopting the MIMO multi-antenna wireless communication technology in the V2V communication system (the V2V communication system adopting the MIMO multi-antenna wireless communication technology is simply referred to as a vehicle-to-vehicle multi-antenna system herein). The existing relevant documents already provide a geometric modeling method of the MIMO channel under the V2V scene, but the model established according to the modeling method of the prior art has low precision and cannot accurately represent the characteristics of the V2V MIMO channel.
Disclosure of Invention
In order to solve at least one of the above technical problems, the present disclosure provides a non-stationary channel modeling method and apparatus for a vehicle-to-vehicle multi-antenna system, which improves the high accuracy of a channel model.
In one aspect of the disclosure, a method of modeling non-stationary channels of a vehicle-to-vehicle multi-antenna system includes:
establishing a double-ring model by taking the transmitting end and the receiving end as circle centers;
establishing a semi-ellipsoid model by taking a transmitting end and a receiving end as focuses;
obtaining a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model;
obtaining a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-ray path and a double-ray path;
a spatio-temporal correlation function is obtained based on a channel impulse response function.
Optionally, the visible gains of the single-ray path and the double-ray path are calculated according to a Hata model path loss formula, and the single-ray path and the double-ray path with the visible gains smaller than the threshold gain are screened out.
Optionally, the channel impulse response function is:
Figure GDA0003123609820000021
in the above formula, the first and second carbon atoms are,
Figure GDA0003123609820000022
representing the direct path component;
Figure GDA0003123609820000023
the components of the single-ray path are represented,
Figure GDA0003123609820000024
representing the bijective path component;
wherein,
Figure GDA0003123609820000025
Figure GDA0003123609820000026
Figure GDA0003123609820000027
optionally, the number of scatterers in each ring region in the double-ring model and the number of scatterers in the semi-ellipsoid model region are set as S, so as to optimize the spatio-temporal correlation function.
Optionally, the obtaining the space-time correlation function based on the channel impulse response function includes:
establishing a space-time function expression:
Figure GDA0003123609820000028
wherein h iskl,pq(t) represents the channel impulse response between k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at time t, hk′l′,p′q′(t) represents the channel impulse response from k 'row l' row antenna elements at the transmitting end to p 'row q' row antenna elements at the receiving end at the time t, wherein tau represents time delay, a symbol for solving conjugate complex number, and E represents the mathematical expectation symbol;
obtaining each path component of the space-time expression based on the space-time function expression and the channel impulse response function:
direct path component:
Figure GDA0003123609820000029
N1single-shot path component:
Figure GDA00031236098200000210
N2single-shot path component:
Figure GDA0003123609820000031
N3single-shot path component:
Figure GDA0003123609820000032
bijective path component:
Figure GDA0003123609820000033
wherein, N1 represents that N1 mobile scatterers are distributed on a ring with a transmitting end as a center, N1 represents the serial number of scatterers on the ring where multipath passes through, N2 represents that N2 mobile scatterers are distributed on a ring with a receiving end as a center, N2 represents the serial number of scatterers on the ring where multipath passes through, N3 represents that N3 static scatterers are distributed on a hemiellipsoid with two centers as focuses, N3 represents the serial number of scatterers on the hemiellipsoid where multipath passes through, and the number of scatterers in each ring region and the number of scatterers in the hemiellipsoid model region are set as S.
In the above formula, K is the Rice factor; e is a constant, j represents an imaginary number, t represents a time variable,
Figure GDA0003123609820000034
indicating the doppler shift of the direct path component from k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure GDA0003123609820000035
representing the reception phase of the direct path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure GDA0003123609820000036
represents the doppler shift of the direct path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end,
Figure GDA0003123609820000037
representing the receiving phase of a direct path component between k 'rows and l' columns of antenna elements at the transmitting end to p 'rows and q' columns of antenna elements at the receiving end at the time t; piAnd PDBIs a normalized power correlation coefficient satisfying
Figure GDA0003123609820000038
Figure GDA0003123609820000039
Is a scatterer niAnd a transmitting terminal MTMaximum doppler shift in between;
Figure GDA00031236098200000310
is a scatterer niAnd receiving end MRMaximum doppler shift in between;
Figure GDA00031236098200000311
is composed of
Figure GDA00031236098200000312
Azimuth in the x-y plane;
Figure GDA00031236098200000313
the Doppler frequency shift of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the moment t is represented;
Figure GDA00031236098200000314
the receiving phase of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the time t is represented; i is 1,2, 3; NLoS represents a non-line-of-sight component;
Figure GDA0003123609820000041
the Doppler frequency shift of a non-direct bijective path component between the k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at the time t is represented;
Figure GDA0003123609820000042
representing the reception phase of the non-direct bijective path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure GDA0003123609820000043
the Doppler frequency shift of a non-direct path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t is represented;
Figure GDA0003123609820000044
representing the receiving phase of a non-direct path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t;
Figure GDA0003123609820000045
the Doppler frequency shift of a non-direct bijective path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t is represented;
Figure GDA0003123609820000046
representing the receive phase of the non-direct bijection path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end.
Optionally, the method further includes predicting the performance of the communication system based on the spatio-temporal correlation function, or verifying the performance of the communication system based on the spatio-temporal correlation function, or performing back-end signal processing based on the spatio-temporal correlation function.
In another aspect of the present disclosure, a non-stationary channel modeling apparatus of a vehicle-to-vehicle multi-antenna system includes:
the double-ring model establishing module is used for establishing a double-ring model by taking the transmitting end and the receiving end as circle centers;
the semi-ellipsoid model establishing module is used for establishing a semi-ellipsoid model by taking the transmitting end and the receiving end as focuses;
the path acquisition module is used for acquiring a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model;
the channel impulse response function acquisition module is used for acquiring a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-shot path and a double-shot path;
and the space-time correlation function acquisition module is used for acquiring a space-time correlation function based on the channel impulse response function.
Optionally, the path obtaining module is further configured to calculate visible gains of the single-transmission path and the double-transmission path according to a Hata model path loss formula, and screen out the single-transmission path and the double-transmission path whose visible gains are smaller than the threshold gain.
Optionally, the apparatus further includes a spatio-temporal correlation function optimization module, configured to make the number of scatterers in each ring region in the dual-ring model and the number of scatterers in the semi-ellipsoid model region be S, and optimize the spatio-temporal correlation function.
Optionally, the apparatus further comprises a processing module, where the processing module is configured to predict performance of the communication system based on the spatio-temporal correlation function, or verify performance of the communication system based on the spatio-temporal correlation function, or perform back-end signal processing based on the spatio-temporal correlation function.
The invention establishes a double-ring model by taking a transmitting end and a receiving end as circle centers; establishing a semi-ellipsoid model by taking a transmitting end and a receiving end as focuses; obtaining a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model; the channel model is established based on the direct path, the single-ray path and the double-ray path, the accuracy of the established model is higher, and the characteristics of the V2V MIMO channel can be well represented.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.
FIG. 1 is a method flow diagram in an exemplary embodiment of the present disclosure;
FIG. 2 is a diagram of channel models in an exemplary embodiment of the present disclosure;
fig. 3 is a device connection diagram in an exemplary embodiment of the present disclosure.
Detailed Description
The present disclosure will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the present disclosure. It should be further noted that, for the convenience of description, only the portions relevant to the present disclosure are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
As illustrated in fig. 1 and 2, a method of non-stationary channel modeling for a vehicle-to-vehicle multi-antenna system, comprising:
step S1: establishing a double-ring model by taking the transmitting end and the receiving end as circle centers;
step S2: establishing a semi-ellipsoid model by taking a transmitting end and a receiving end as focuses;
step S3: obtaining a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model;
step S4: obtaining a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-ray path and a double-ray path;
step S5: a spatio-temporal correlation function is obtained based on a channel impulse response function.
Transmitting terminal M of the vehicle-to-vehicle multi-antenna system of the present embodimentTAnd a receiving end MRThe method is a method for establishing a channel model from k rows and l columns of a transmitting end to p rows and q columns of receiving end antenna elements.
As shown in fig. 2, in step S1, the dual-ring model includes a first ring centered on the transmitting end and a second ring centered on the receiving end, and the radius of the first ring is denoted as RtAnd the second ring radius is denoted as RrThe semi-ellipsoid model takes a transmitting end and a receiving end as ellipses in the modelThe major and minor semi-axes of the ellipse are respectively a and b, and the focal distance is D0。
The vector of the moving speed of the transmitting terminal is recorded as vTN is distributed on the first ring with the transmitting end as the center1A moving velocity vector of
Figure GDA0003123609820000061
Vehicle (i.e. first scatterer N)1') to a host; the receiving end moving velocity vector is denoted as vRN is distributed on the second ring taking the receiving end as the center of circle2A moving velocity vector of
Figure GDA0003123609820000062
Vehicle (i.e. second scatterer N)2') to a host; consider a vehicle traveling along a road, assuming all speed directions are in the positive x-axis direction. Assume that the semi-ellipsoid model (semi-ellipsoid region in FIG. 2) is distributed with N3A stationary scatterer (i.e. a third scatterer N)2'). In this application, N'iRepresenting scatterers themselves, NiDenotes the number of scatterers, niIs N'iThe value of a single scatterer in the scatterer set is 1 to Ni。
The direct path in step S3 is a direct path from the transmitting end to the receiving end, the single path is a path from the transmitting end to the receiving end through one scatterer (a first scatterer, a second scatterer, or a third scatterer), and the bijective path is a path from the transmitting end to the receiving end through two scatterers (a first scatterer and a second scatterer).
According to the technical scheme, the direct path component (namely the line-of-sight component), the single-shot component of the static scatterer, the single-shot component of the movable scatterer and the secondary scattering component of the movable scatterer are combined to obtain the channel impulse response function and the space-time correlation function, so that the model precision is higher, and the model precision is closer to the actual environment of vehicle communication.
Channel impulse response hkl,pq(t) passing from the direct path component through N1′，N2′，N3The single ray path component of and through N1′N2The bijective path component of' consists of.
The concrete expression is as follows:
Figure GDA0003123609820000071
Figure GDA0003123609820000072
representing the direct path component;
Figure GDA0003123609820000073
the components of the single-ray path are represented,
Figure GDA0003123609820000074
representing the bijective path component.
Specifically, subscript kl in the formula represents k rows and l columns of a transmitting end, pq represents p rows and q columns of a receiving end, and t represents a time variable;
Figure GDA0003123609820000075
representing a direct path component from a transmitting end k row l column to a receiving end p row q column under a time variable t;
Figure GDA0003123609820000076
represents the k rows and l columns of a transmitting terminal to pass through n under the time variable tiA single-shot path component of p rows and q columns to a receiving end;
Figure GDA0003123609820000077
represents the k rows and l columns of a transmitting terminal to pass through n under the time variable t1And n2And p rows and q columns of bijective path components to the receiving end.
Wherein:
direct path component:
Figure GDA0003123609820000078
k is the Rice factor, e is a constant, and has a value of about 2.71828,
Figure GDA0003123609820000079
indicating the doppler shift of the direct path,
Figure GDA00031236098200000710
representing the received phase of the direct path component. j represents an imaginary number, the square equals-1, and t represents a time variable. In particular, the method comprises the following steps of,
Figure GDA00031236098200000711
represents the Doppler frequency shift of the direct path component from k rows and l columns at the transmitting end to p rows and q columns at the receiving end under the time variable t,
Figure GDA00031236098200000712
and the receiving phase of the direct path component from k rows and l columns of the transmitting end to p rows and q columns of the receiving end under the time variable t is shown.
Single-shot path component:
Figure GDA00031236098200000713
k is the Rice factor, i ═ 1,2,3, PiIs a normalized power-related coefficient that is,
Figure GDA00031236098200000714
is a scatterer niAnd MT(MR) Maximum Doppler shift therebetween, i.e.
Figure GDA00031236098200000715
Represents a scatterer niAnd a transmitting terminal MTThe maximum doppler shift in between is determined,
Figure GDA00031236098200000716
represents a scatterer niAnd receiving end MRMaximum doppler shift in between; as shown in figure 2 of the drawings, in which,
Figure GDA00031236098200000717
is composed of
Figure GDA00031236098200000718
In the x-y plane, i.e. azimuth
Figure GDA00031236098200000719
Is composed of
Figure GDA00031236098200000720
In the azimuth of the x-y plane,
Figure GDA00031236098200000721
is composed of
Figure GDA00031236098200000722
Azimuth in the x-y plane;
Figure GDA00031236098200000723
is that the k rows and l columns of the transmitter pass n under the time variable tiReceiving end M in direct path component to p rows and q columns of receiving endRThe path segment on one side, for example when i is 3,
Figure GDA0003123609820000081
represents a scatterer n3To the receiving end MRA segment;
Figure GDA0003123609820000082
the receive phase, in particular,
Figure GDA0003123609820000083
represents the k rows and l columns of a transmitting terminal to pass through n under the time variable tiAnd (3) receiving phases of the single-ray path components of p rows and q columns to the receiving end. The formula parameters in this application are named as above.
Bijective path component:
Figure GDA0003123609820000084
k is the Rice factor, PiAnd PDBIs normalizedChange the power correlation coefficient to satisfy
Figure GDA0003123609820000085
Figure GDA0003123609820000086
Figure GDA0003123609820000087
Is a scatterer n1And a transmitting terminal MTThe maximum doppler shift in between is determined,
Figure GDA0003123609820000088
is a scatterer n2And receiving end MRMaximum doppler shift in between.
Figure GDA0003123609820000089
A receive phase representing the bijective path component;
Figure GDA00031236098200000810
is composed of
Figure GDA00031236098200000811
In the azimuth of the x-y plane,
Figure GDA00031236098200000812
is composed of
Figure GDA00031236098200000813
The azimuth angle in the x-y plane, specifically,
Figure GDA00031236098200000814
represents the k rows and l columns of a transmitting terminal to pass through n under the time variable t1And n2Receiving phase of bijection path component of p rows and q columns to a receiving end;
Figure GDA00031236098200000815
is that the k rows and l columns of the transmitter pass n under the time variable t1Transmitting end M in direct path component to receiving end p rows and q columnsTPath sections on one side, i.e. freeProjectile n1To the transmitting end MTA segment;
Figure GDA00031236098200000816
is that the k rows and l columns of the transmitter pass n under the time variable t2Receiving end M in direct path component to p rows and q columns of receiving endROne side of the path section, i.e. the diffuser n2To the receiving end MRAnd (4) section.
The doppler shift of each path component can be expressed as:
Figure GDA00031236098200000817
Figure GDA00031236098200000818
Figure GDA00031236098200000819
wherein,<>representing the vector inner product, i.e. dot product. | | | represents a modulus value. The definition of vector inner product is used here, and the inner product of two vectors is divided by the module value of two vectors, which is equal to the cosine value of the included angle between the two vectors.
Figure GDA00031236098200000820
Is a scatterer niAnd MT(MR) Maximum Doppler shift therebetween, i.e.
Figure GDA00031236098200000821
Is a scatterer n1And MTThe maximum doppler shift in between is determined,
Figure GDA00031236098200000822
is a scatterer n1And MRThe maximum doppler shift in between is determined,
Figure GDA00031236098200000823
is a scattering bodyn2And MRThe maximum doppler shift in between is determined,
Figure GDA00031236098200000824
is a scatterer n2And TRλ c/f, the maximum doppler shift betweenc，fcIs the carrier frequency and c is the speed of light.
The receive phase of each path component can be expressed as:
Figure GDA0003123609820000091
Figure GDA0003123609820000092
Figure GDA0003123609820000093
Figure GDA0003123609820000094
wherein the initial phase
Figure GDA0003123609820000095
Figure GDA0003123609820000096
Is composed of
Figure GDA0003123609820000097
In the x-y plane. Taking into account stationary scatterers N3The method is used for representing high-rise buildings, trees and other real objects in the surrounding environment of the street, and the height is not negligible during modeling. Note the book
Figure GDA0003123609820000098
Is composed of
Figure GDA0003123609820000099
The angle of elevation of (a) is,
Figure GDA00031236098200000910
is composed of
Figure GDA00031236098200000911
The spatial angle with the x-axis is:
Figure GDA00031236098200000912
Figure GDA00031236098200000913
considering the non-stationary characteristic of the channel, the time delay is denoted as τ, and the time-varying parameter is updated at time t + τ as follows:
Figure GDA00031236098200000914
Figure GDA00031236098200000915
Figure GDA00031236098200000916
based on large-scale loss, considering the influence of distance and path loss factors, dividing visible regions of scatterers, and selecting a Hata model path loss formula according to the street environment characteristics corresponding to a proposed model:
Figure GDA00031236098200000917
where dB is the unit of the number of bits,
Figure GDA00031236098200000918
to be in phase with a receiving antennaCoefficient of correlation, hT、hRRespectively, the height of the transmit and receive antennas, for medium-sized coverage,
Figure GDA00031236098200000919
the values are as follows:
Figure GDA00031236098200000920
according to the scene characteristics of the model, h is obtainedT＝hRAnd (5) arranging to obtain a path loss calculation formula of the model:
PLHata(d)[dB]＝68.75+27.72log fc+44.9log d (19)
and (3) disregarding the power loss at the scattering point to obtain a total formula of visible gain calculation of the single-ray path and the double-ray path:
Figure GDA0003123609820000101
if the visible gain is larger than or equal to the threshold gain, the effective single-ray path and the effective double-ray path are reserved; if the visible gain is smaller than the threshold gain, the invalid path is screened out, and the path component is not considered when the space-time correlation function is calculated.
The space-time correlation function can describe the variation condition of the channel in time and space, characterize the channel characteristics, and calculate the expression as follows:
Figure GDA0003123609820000102
wherein represents a complex conjugate, E [ alpha ], [ alpha ] and [ alpha ], [ alpha ] or an]Expressing an average value; rhok′l′p′q′,klpq(t, τ) represents a correlation function between channels from k 'row/column at the transmitting end to p' row/column at the receiving end and channels from k row/column at the transmitting end to p row/column at the receiving end under the condition of time t and time delay τ.
Figure GDA0003123609820000103
The channel impulse response from k 'row/column at the transmitting end to p' row/column at the receiving end under the condition of time t and time delay tau is shown.
In the conventional assumption, the number of scatterers in the model tends to be infinite, and the angle of departure (AoD) and angle of arrival (AoA) are each represented by a continuously varying probability density distribution. Based on this assumption, each path component in the above equation is separately subjected to the following expansion calculation, wherein the direct path component (LoS path component):
Figure GDA0003123609820000104
N1’，N2' Single shot path component:
Figure GDA0003123609820000105
N3' Single shot path component:
Figure GDA0003123609820000111
bijective path component:
Figure GDA0003123609820000112
considering the number of scatterers in the actual scene should be limited, let N1＝N2＝N3The form of integration is adjusted to the following summation:
N1single-shot path component:
Figure GDA0003123609820000113
N2single-shot path component:
Figure GDA0003123609820000114
N3single-shot path component:
Figure GDA0003123609820000115
bijective path component:
Figure GDA0003123609820000116
the formula parameters can be referred to the explanations in the foregoing;
let the delay factors τ be 0 and k 'l' p 'q' be klpq, respectively, and the space-time correlation function be simplified to obtain a space-time correlation function (CCF) and a time-time correlation function (ACF), respectively.
After the space-time correlation function, the performance of the communication system can be predicted based on the space-time correlation function, the performance of the communication system is verified based on the space-time correlation function, and the back-end signal processing is carried out based on the space-time correlation function.
In this embodiment, the variation of the channel under the combined action of the stationary scatterer and the mobile scatterer is explored by combining a double-ring model and a semi-ellipsoid model (semi-ellipsoid model), and a uniform planar array is adopted for the antenna to characterize the near-field effect of the spherical wave. The visible scattering region is divided by different path losses, and the space-time correlation function is analyzed by changing parameters. The final effect can be displayed by computer simulation.
In another aspect of the present embodiment, as shown in fig. 3, a non-stationary channel modeling apparatus of a vehicle-to-vehicle multi-antenna system includes:
the double-ring model establishing module 1 is used for establishing a double-ring model by taking a transmitting end and a receiving end as circle centers;
the semi-ellipsoid model establishing module 2 is used for establishing a semi-ellipsoid model by taking the transmitting end and the receiving end as focuses;
the path acquisition module 3 is used for acquiring a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model;
the channel impulse response function acquisition module 4 is used for acquiring a channel impulse response function from the transmitting end to the receiving end based on a direct path, a single-shot path and a double-shot path;
and a space-time correlation function obtaining module 5, configured to obtain a space-time correlation function based on the channel impulse response function.
Optionally, the path obtaining module is further configured to calculate visible gains of the single-transmission path and the double-transmission path according to a Hata model path loss formula, and screen out the single-transmission path and the double-transmission path whose visible gains are smaller than the threshold gain.
Optionally, the apparatus further includes a spatio-temporal correlation function optimization module, configured to make the number of scatterers in each ring region in the dual-ring model and the number of scatterers in the semi-ellipsoid model region be S, and optimize the spatio-temporal correlation function.
Optionally, the apparatus further comprises a processing module, where the processing module is configured to predict performance of the communication system based on the spatio-temporal correlation function, or verify performance of the communication system based on the spatio-temporal correlation function, or perform back-end signal processing based on the spatio-temporal correlation function.
The apparatus in this embodiment is used to implement the method in the above-described embodiment, and the principle and effect of the apparatus are the same as those of the method, and the description of this embodiment is not repeated.
The embodiment provides a 3D non-stationary V2V MIMO communication channel model based on geometry for a vehicle communication scene, based on uniform planar array antenna configuration, and by using a double-ring and semi-ellipsoid model (semi-ellipsoid), the distribution of static scatterers and moving scatterers in the environment is comprehensively considered, and the number of the scatterers is subjected to finite approximation. Meanwhile, a direct path component (a line-of-sight component), a single-shot component through a static scatterer, a single-shot component through a moving scatterer and a secondary scattering component through the moving scatterer are combined, a channel impulse response and a space-time correlation function expression are deduced, and a visible region division algorithm of the scatterer is designed by taking the power attenuation degree of a transmission path as a basis. Finally, the influence of different parameters on the channel correlation is analyzed through simulation, and the result shows that the proposed model can well represent the characteristics of the V2V MIMO channel.
In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of illustration of the disclosure and are not intended to limit the scope of the disclosure. Other variations or modifications may occur to those skilled in the art, based on the foregoing disclosure, and are still within the scope of the present disclosure.

Claims (4)

1. A method of modeling non-stationary channels of a vehicle-to-vehicle multi-antenna system, comprising:
establishing a double-ring model by taking the transmitting end and the receiving end as circle centers;
establishing a semi-ellipsoid model by taking a transmitting end and a receiving end as focuses;
obtaining a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model;
calculating the visible gains of the single-ray path and the double-ray path according to a Hata model path loss formula, and screening out the single-ray path and the double-ray path of which the visible gains are smaller than a threshold gain;
obtaining a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-ray path and a double-ray path;
obtaining a space-time correlation function based on a channel impulse response function;
wherein,
Figure FDA0003123609810000011
Figure FDA0003123609810000012
Figure FDA0003123609810000013
is that k rows and l columns at a transmitting end pass through a static scatterer n under a time variable t3Transmitting end M in direct path component to receiving end p rows and q columnsTOr receiving end MRThe path section on one side of the device,
Figure FDA0003123609810000014
is a direct path section from k rows and l columns of a transmitting end to p rows and q columns of a receiving end under a time variable t,
Figure FDA0003123609810000015
is composed of
Figure FDA0003123609810000016
The angle of elevation of (a) is,
Figure FDA0003123609810000017
is composed of
Figure FDA0003123609810000018
The spatial angle with the x-axis is,
Figure FDA0003123609810000019
is that
Figure FDA00031236098100000110
Azimuth in the x-y plane;
the obtaining the space-time correlation function based on the channel impulse response function comprises:
establishing a space-time function expression:
Figure FDA00031236098100000111
wherein h iskl,pq(t) represents the channel impulse response between k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at time t, hk′l′,p′q′(t) represents the channel impulse response from k 'row l' row antenna elements at the transmitting end to p 'row q' row antenna elements at the receiving end at the time t, wherein tau represents time delay, a symbol for solving conjugate complex number, and E represents the mathematical expectation symbol;
obtaining each path component of the space-time expression based on the space-time function expression and the channel impulse response function:
direct path component:
Figure FDA0003123609810000021
N1single-shot path component:
Figure FDA0003123609810000022
N2single-shot path component:
Figure FDA0003123609810000023
N3single-shot path component:
Figure FDA0003123609810000024
bijective path component:
Figure FDA0003123609810000025
wherein N is1Indicating that N is distributed on the ring with the transmitting end as the center1A moving scatterer, n1Number of scatterers on the ring representing multipath2Indicating that N is distributed on the ring with the receiving end as the center2A moving scatterer, n2Number of scatterers on the ring representing multipath3Showing that N is distributed on a semi-ellipsoid taking two circle centers as focuses3A static scatterer, n3Representing the serial number of scatterers on a semi-ellipsoid passed by multipath, and making the number of scatterers in each ring region and the number of scatterers in the semi-ellipsoid model region in a double-ring model be S;
the channel impulse response function is:
Figure FDA0003123609810000026
in the above formula, the first and second carbon atoms are,
Figure FDA0003123609810000027
representing the direct path component;
Figure FDA0003123609810000028
the components of the single-ray path are represented,
Figure FDA0003123609810000029
representing the bijective path component;
wherein,
Figure FDA00031236098100000210
Figure FDA0003123609810000031
Figure FDA0003123609810000032
in the above formula, K is the Rice factor; e is a constant, j represents an imaginary number, t represents a time variable,
Figure FDA0003123609810000033
indicating the doppler shift of the direct path component from k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA0003123609810000034
representing the reception phase of the direct path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA0003123609810000035
represents the doppler shift of the direct path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end,
Figure FDA0003123609810000036
representing the receiving phase of a direct path component between k 'rows and l' columns of antenna elements at the transmitting end to p 'rows and q' columns of antenna elements at the receiving end at the time t; piAnd PDBIs a normalized power correlation coefficient satisfying
Figure FDA0003123609810000037
Figure FDA0003123609810000038
Is a scatterer niAnd a transmitting terminal MTMaximum doppler shift in between;
Figure FDA0003123609810000039
is a scatterer niAnd receiving end MRMaximum doppler shift in between;
Figure FDA00031236098100000310
is composed of
Figure FDA00031236098100000311
Azimuth in the x-y plane;
Figure FDA00031236098100000312
the Doppler frequency shift of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the moment t is represented;
Figure FDA00031236098100000313
the receiving phase of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the time t is represented; i is 1,2, 3; NLoS represents a non-line-of-sight component;
Figure FDA00031236098100000314
the Doppler frequency shift of a non-direct bijective path component between the k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at the time t is represented;
Figure FDA00031236098100000315
representing the reception phase of the non-direct bijective path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA00031236098100000316
the Doppler frequency shift of a non-direct path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t is represented;
Figure FDA00031236098100000317
representing the receiving phase of a non-direct path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t;
Figure FDA00031236098100000318
the Doppler frequency shift of a non-direct bijective path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t is represented;
Figure FDA00031236098100000319
representing the receive phase of the non-direct bijection path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end.
2. The method of claim 1, further comprising predicting communication system performance based on a spatio-temporal correlation function, or verifying communication system performance based on a spatio-temporal correlation function, or performing back-end signal processing based on a spatio-temporal correlation function.
3. A non-stationary channel modeling apparatus for a vehicle-to-vehicle multi-antenna system, comprising:
the double-ring model establishing module is used for establishing a double-ring model by taking the transmitting end and the receiving end as circle centers;
the semi-ellipsoid model establishing module is used for establishing a semi-ellipsoid model by taking the transmitting end and the receiving end as focuses;
the path acquisition module is used for acquiring a direct path, a single-shot path and a bishot path based on the double-ring model and the semi-ellipsoid model; calculating the visible gains of the single-ray path and the double-ray path according to a Hata model path loss formula, and screening out the single-ray path and the double-ray path of which the visible gains are smaller than a threshold gain;
the channel impulse response function acquisition module is used for acquiring a channel impulse response function from a transmitting end to a receiving end based on a direct path, a single-shot path and a double-shot path;
wherein,
Figure FDA0003123609810000041
Figure FDA0003123609810000042
Figure FDA0003123609810000043
is that k rows and l columns at a transmitting end pass through a static scatterer n under a time variable t3Transmitting end M in direct path component to receiving end p rows and q columnsTOr receiving end MRThe path section on one side of the device,
Figure FDA0003123609810000044
is a direct path section from k rows and l columns of a transmitting end to p rows and q columns of a receiving end under a time variable t,
Figure FDA0003123609810000045
is composed of
Figure FDA0003123609810000046
The angle of elevation of (a) is,
Figure FDA0003123609810000047
is composed of
Figure FDA0003123609810000048
The spatial angle with the x-axis is,
Figure FDA0003123609810000049
is that
Figure FDA00031236098100000410
Azimuth in the x-y plane;
a spatio-temporal correlation function acquisition module for
Establishing a space-time function expression:
Figure FDA00031236098100000411
wherein h iskl,pq(t) represents the channel impulse response between k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at time t, hk′l′,p′q′(t) represents the channel impulse response from k 'row l' row antenna elements at the transmitting end to p 'row q' row antenna elements at the receiving end at the time t, wherein tau represents time delay, a symbol for solving conjugate complex number, and E represents the mathematical expectation symbol;
obtaining each path component of the space-time expression based on the space-time function expression and the channel impulse response function:
direct path component:
Figure FDA0003123609810000051
N1single-shot path component:
Figure FDA0003123609810000052
N2single-shot path component:
Figure FDA0003123609810000053
N3single-shot path component:
Figure FDA0003123609810000054
bijective path component:
Figure FDA0003123609810000055
wherein N is1Indicating that N is distributed on the ring with the transmitting end as the center1A moving scatterer, n1Number of scatterers on the ring representing multipath2Indicating that N is distributed on the ring with the receiving end as the center2A moving scatterer, n2Number of scatterers on the ring representing multipath3Showing that N is distributed on a semi-ellipsoid taking two circle centers as focuses3A static scatterer, n3Representing the serial number of scatterers on a semi-ellipsoid passed by multipath, and making the number of scatterers in each ring region and the number of scatterers in the semi-ellipsoid model region in a double-ring model be S;
the channel impulse response function is:
Figure FDA0003123609810000056
in the above formula, the first and second carbon atoms are,
Figure FDA0003123609810000057
representing the direct path component;
Figure FDA0003123609810000058
the components of the single-ray path are represented,
Figure FDA0003123609810000059
representing the bijective path component;
wherein,
Figure FDA0003123609810000061
Figure FDA0003123609810000062
Figure FDA0003123609810000063
in the above formula, K is the Rice factor; e is a constant, j represents an imaginary number, t represents a time variable,
Figure FDA0003123609810000064
indicating the doppler shift of the direct path component from k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA0003123609810000065
representing the reception phase of the direct path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA0003123609810000066
represents the doppler shift of the direct path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end,
Figure FDA0003123609810000067
representing the receiving phase of a direct path component between k 'rows and l' columns of antenna elements at the transmitting end to p 'rows and q' columns of antenna elements at the receiving end at the time t; piAnd PDBIs a normalized power correlation coefficient satisfying
Figure FDA0003123609810000068
Figure FDA0003123609810000069
Is a scatterer niAnd a transmitting terminal MTMaximum doppler shift in between;
Figure FDA00031236098100000610
is a scatterer niAnd receiving end MRMaximum doppler shift in between;
Figure FDA00031236098100000611
is composed of
Figure FDA00031236098100000612
Azimuth in the x-y plane;
Figure FDA00031236098100000613
the Doppler frequency shift of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the moment t is represented;
Figure FDA00031236098100000614
the receiving phase of a non-direct path component between k rows and l columns of antenna elements at a transmitting end and p rows and q columns of antenna elements at a receiving end at the time t is represented; i is 1,2, 3; NLoS represents a non-line-of-sight component;
Figure FDA00031236098100000615
the Doppler frequency shift of a non-direct bijective path component between the k rows and l columns of antenna elements at the transmitting end and p rows and q columns of antenna elements at the receiving end at the time t is represented;
Figure FDA00031236098100000616
representing the reception phase of the non-direct bijective path component between k rows and l columns of antenna elements at the transmitting end to p rows and q columns of antenna elements at the receiving end at time t,
Figure FDA00031236098100000617
indicating that at time t, the antenna elements are k 'row/column' from the transmitting end to p 'row q' from the receiving end' Doppler shift of the non-direct path component between the column antenna elements;
Figure FDA00031236098100000618
representing the receiving phase of a non-direct path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t;
Figure FDA00031236098100000619
the Doppler frequency shift of a non-direct bijective path component between k 'rows and l' columns of antenna elements at the transmitting end and p 'rows and q' columns of antenna elements at the receiving end at the time t is represented;
Figure FDA00031236098100000620
representing the receive phase of the non-direct bijection path component between k ' rows/columns of antenna elements at time t from the transmitting end to p ' rows q ' columns of antenna elements at the receiving end.
4. The apparatus of claim 3, wherein the apparatus further comprises a processing module for predicting communication system performance based on a spatiotemporal correlation function, or verifying communication system performance based on a spatiotemporal correlation function, or performing back-end signal processing based on a spatiotemporal correlation function.
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