Crossroad street wireless propagation channel modeling method

Abstract

The invention discloses a crossroad street wireless propagation channel modeling method, which comprises the following steps of: constructing a crossroad geometric channel model according to the size of a real crossroad street, dividing the geometric model into a plurality of scatterers, and configuring uniform linear antenna arrays on a transmitting end and a receiving end, a time-varying transfer function of the model is obtained by using a geometrical relationship among a transmitting end, a receiving end and a scatterer in a cross street, spatial domain, time domain and frequency domain characteristics of the cross street geometric channel model are researched, and an incident angle and a transmitting angle are obtained by using the geometrical relationship in a cross street scattering scene and a triangular identical equation. The time-varying transfer function of the model is further perfected, expected value calculation is performed on the transfer function of any two antenna propagation paths to obtain the space-time-frequency cross-correlation function of the line-of-sight and the non-line-of-sight, important theoretical reference and design analysis basis are provided for channel measurement, modeling and estimation of a wireless communication system, and the method has important theoretical and application values.

Description

Technical Field

[0001] The invention relates to a method for modeling a wireless propagation channel at a crossroad street, and in particular to the technical field of building a channel model for an urban street. Background Art

[0002] Vehicle-to-vehicle (V2V) communication system refers to a communication method in which vehicles can exchange their respective motion states through wireless communication protocols. As a new traffic telematics application, it can improve the safety and mobility of various roads under different propagation environments. An efficient V2V system can integrate information and communication technologies into transportation infrastructure, cars and other devices, which are also called intelligent transportation systems. In order to improve the safety of V2V communication, corresponding research projects have been carried out worldwide, such as the Vehicle-to-Vehicle Communication Alliance and the European Road Transport Telecommunications Implementation Coordination Organization. V2V communication systems have been developed to date, but there are still some technical difficulties, such as different signal transmission environments and information loss caused by vehicle movement. Therefore, in order to meet the needs of V2V communication, it is particularly important to study the wireless communication channel environment between the mobile transmitter (MT) and the receiver (MR) in different environments. In recent years, many teams at home and abroad have proposed a variety of channel models for V2V communication environments, such as elliptical models and straight street models. For dense urban street environments, M. Patzold provided a pseudo-geometric scattering channel model that visualizes double / triple bounce paths as single bounce paths; Ghorash conducted a polar analysis of the 2.2GHz urban non-line-of-sight (NLOS) propagation channel based on measured data in Tokyo and Yokohama; MacCartney conducted two measurement campaigns in urban microcellular environments and proposed a path loss model suitable for 5G standard formulation. Rasekh used a street canyon approximation model to consider the rough surface of the 60GHz wireless channel in the urban environment. Combining the above discussion, it can be found that the previous channel models cannot cover all important scattering environments and ignore the mutual motion of MT and MR and the impact of the moving direction on the statistical characteristics of the channel. Summary of the invention

[0003] The purpose of the present invention is to provide a method for modeling a wireless propagation channel at a crossroad street, so as to simulate the influence of the movement of small vehicles on the statistical characteristics of the channel in a real dense urban street vehicle-mounted mobile communication environment.

[0004] In order to achieve the above objectives / solve the above technical problems, the present invention is implemented by adopting the following technical solutions.

[0005] In a first aspect, the present invention provides a method for modeling a wireless propagation channel at a crossroad street, comprising:

[0006] According to the street dimensions of the intersection, a geometric channel model of the intersection is constructed;

[0007] The intersection geometric channel model is divided into several scatterers, and the moving vehicles in the intersection geometric channel model are divided into transmitting ends and receiving ends;

[0008] A rectangular coordinate system is established with the receiving end as the origin, and the propagation link is obtained through the positions of the transmitting end, the receiving end and the scatterer in the coordinate system. The time-varying channel impulse response of the intersection geometric channel model is calculated by the signal from the transmitting end to the receiving end through the line-of-sight path or non-line-of-sight path of the propagation link;

[0009] According to the positional relationship between the transmitting end and the receiving end, the incident angle and the emission angle of the signal in the horizontal plane and the vertical plane are calculated;

[0010] The time-varying channel impulse response is transformed into a time-varying channel frequency response function through Fourier transform, and the statistical characteristics of the intersection street model are calculated by combining the incident angle and the emission angle.

[0011] Furthermore, the intersection geometric channel model includes: the transmitter and the receiver move toward each other on a straight road or the transmitter and the receiver move vertically at a T-intersection; when the transmitter and the receiver move toward each other on a straight road, their scatterers are evenly distributed on the street, which are street scatterers; when the transmitter and the receiver move vertically at a T-intersection, the scatterers are distributed at street corners, which are street corner scattering clusters.

[0012] Furthermore, when the transmitting end and the receiving end move toward each other on a straight road, the time-varying channel impulse response of the calculation of the intersection geometric channel model specifically includes:

[0013] Time-varying channel impulse response The calculation process is:

[0014] ,

[0015] in: is the delay, t is the time, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the line-of-sight component, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path; is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path;

[0016] h kl LOS ( t ′ , t ) = c R c R + 1 e − j 2 π f c t ′ LOS kl ⋅ e j [ 2 π f T LOS t cos( α T − c T ) + 2 π f R LOS t cos( β R − c R ) + i LOS ] , ,

[0017] ,

[0018] Where j is the imaginary unit, is the Rice factor; is the carrier frequency; , , are independently distributed random variables in the interval ( 0 , 2 π ] Follow uniform distribution; is the signal emission angle, is the signal incident angle, is the angle of the transmitting antenna in the xy plane relative to the x-axis direction, is the angle of the receiving antenna in the xy plane relative to the x-axis direction; is the Doppler shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler frequency shift caused by the motion of the receiver under the line-of-sight path, ; is the Doppler shift caused by the movement of the transmitter in the non-line-of-sight path, ; is the Doppler shift caused by the movement of the receiving end in the non-line-of-sight path, ; is the angle between the transmitting end's motion direction and the x-axis, is the angle between the receiving end's moving direction and the x-axis, is the moving speed of the transmitter, is the moving speed of the receiving end; For the line-of-sight component signal, the transmission link The propagation delay of The line-of-sight component signal passes through the propagation link Propagation delay, For the line-of-sight component signal, the transmission link The propagation delay of is a street scatterer, is the kth transmitting antenna element at the transmitting end, is the lth transmitting antenna element at the receiving end; M is the total number of street scatterers on the x-axis side, m is the mth street scatterer on the x-axis side, N is the total number of street scatterers on the y-axis side, n is the nth street scatterer on the y-axis side;

[0019] ,

[0020] ,

[0021] ,

[0022] ,

[0023] ,

[0024] ,

[0025] ,

[0026] ,

[0027] in: is the speed of light, (x, y) is the scatterer in the rectangular coordinate system The location coordinates of

[0028] For signals propagating over line-of-sight links The distance, x R is the distance of the receiving end on the x-axis, x T is the distance of the transmitter on the x-axis, y R is the distance of the receiving end on the y axis, y T is the distance of the transmitter on the y axis; The distance from the transmitter to the street scatterer in the non-line-of-sight transmission link The distance The distance from the transmitting signal antenna k to the street scatterer in the non-line-of-sight transmission link The distance, M T is the number of transmitting antennas, is the spacing between the transmitting antenna elements; Street scatterers in non-line-of-sight links The distance to the receiving end, Street scatterers in non-line-of-sight links The distance to the receiving antenna L, M R is the number of antennas at the receiving end, is the spacing between antenna elements at the receiving end.

[0029] Furthermore, when the transmitting end and the receiving end move toward each other on a straight road, the incident angle and the emission angle of the signal in the horizontal plane and the vertical plane specifically include the following steps:

[0030] ,

[0031] ,

[0032] in, ,when hour J 1 = [ w b , R ] ,when hour, J 2 = [ − R , − w m − w n ] , i is the intermediate variable taken to simplify the formula, D 1 is the horizontal straight line distance between the receiving end and the transmitting end in the x-axis direction, R is the radius of the circular street with the receiving end as the origin, and w m is the vertical distance between the transmitter and the receiver on the x-axis, w n is the vertical straight-line distance between the transmitter and the street in the y-axis direction, w b When the vehicles move in a straight line towards each other, the distance between the receiving end and the left side of the road, w c is the vertical distance between the right corner of the transmitting end and the receiving end on the y-axis, w x It is the vertical distance of the road perpendicular to the direction of the vehicle's straight-line movement.

[0033] Furthermore, when the transmitting end and the receiving end move toward each other on a straight road, the time-varying channel impulse response is converted into a time-varying channel frequency response function through Fourier transformation, and the statistical characteristics of the intersection street model are calculated in combination with the incident angle and the emission angle, which specifically include the following steps:

[0034] When the transmitter and the receiver move towards each other on a straight road, the time-varying channel impulse response is transformed into the time-varying channel frequency response function through Fourier transformation:

[0035] ,

[0036] in: for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function;

[0037] The space-time-frequency cross-correlation function when driving on a straight road is:

[0038] ,

[0039] in: is the Doppler shift, is the carrier frequency of the signal, (*) is the complex conjugate, and E{.} is the expectation operator;

[0040] The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is:

[0041] ,

[0042] in,

[0043] ,

[0044] ,

[0045] in, is the time delay of the propagation path of the non-line-of-sight reflection component. The average processing result is and For the receiving end and Antennas and ≠ , and The transmitter and Antennas and ≠ ; and To simplify the formula, we use the intermediate variables: The transmitting end is affected by street scatterers The Doppler frequency caused by the impact;

[0046] The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is:

[0047] ,

[0048] ,

[0049] ,

[0050] ,

[0051] in, and Intermediate variables taken to simplify the formula; is the probability density distribution of the incident angle, and it obeys the von Mises distribution, is the zero-order modified Bessel function, represents a measure of concentration, is the average value of the receiving angle, when As time goes to infinity, That is the Gaussian distribution;

[0052] The spatial-temporal-frequency cross-correlation function of the line-of-sight component is:

[0053] ,

[0054] in, is the time delay of the line-of-sight reflection component propagation path, is the Ricean factor of the sight-range component;

[0055] when When , the spatial cross-correlation function between the transmitter and the receiver when traveling on a straight road is:

[0056] ,

[0057] The time autocorrelation function of the transmitter and receiver when traveling on a straight road is:

[0058] .

[0059] Furthermore, when the transmitter and receiver move vertically at the T-intersection, the time-varying channel impulse response of the intersection geometric channel model is calculated. Specifically include:

[0060] ,

[0061] in: is the impulse response function from the pth transmitting antenna element at the transmitting end to the qth receiving antenna element at the receiving end under the signal line-of-sight component, The signal non-line-of-sight component passes through the first street corner scattering cluster The impulse response of The signal non-line-of-sight component passes through the second street corner scattering cluster The impulse response of The non-line-of-sight component of the signal passes through the third street corner scattering cluster The impulse response of

[0062] , h pq SBT ( t ) = lim M →∞ 1 ( c R + 1 ) M ∑ m = 1 M e − j 2 π f c t ′ m e j [ 2 π f m T t cos( α T m − f T ) + 2 π f m R t cos( β T m − f R ) + i m ] ,

[0063] h pq SBR ( t ′ , t ) = lim N →∞ 1 ( c R + 1 ) N ∑ n = 1 N e − j 2 π f c t ′ n e j [ 2 π f n T t cos( α R n − f T ) + 2 π f n R t cos( β R n − f R ) + i n ] ,

[0064] h pq SBC ( t ′ , t ) = lim K →∞ 1 ( c R + 1 ) K ∑ k = 1 K e − j 2 π f c t ′ k e j [ 2 π f k T t cos( α C k − f T ) + 2 π f k R t cos( β C k − f R ) + i k ] ,

[0065] in: is the emission angle of the line-of-sight component, is the incident angle of the sight component, is the phase of the line-of-sight component; The non-line-of-sight component signal passes through the first scattering cluster Emission angle, The non-line-of-sight component signal passes through the first scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the second scattering cluster Emission angle, The non-line-of-sight component signal passes through the second scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the third scattering cluster Emission angle, The non-line-of-sight component signal passes through the third scattering cluster Angle of incidence; The signal passes through the first scattering cluster The phase at a particular moment caused by The signal passes through the second scattering cluster The phase at a particular moment caused by The signal passes through the third scattering cluster The phase at a specific moment caused by are all independently distributed random variables in the interval ( 0 , 2 π ] Follow uniform distribution; is the Doppler shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler shift caused by the motion of the receiving end in the line-of-sight path, ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The path that the line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of

[0066] ,

[0067] ,

[0068] in: The path from the transmitter to the receiver of the line-of-sight component signal The distance

[0069] ,

[0070] ,

[0071] ,

[0072] in: To transmit the signal p to the first scattering cluster The distance The signal transmitted from the p end to the first scattering cluster at time t The distance The first scattering cluster The distance from the center of the transmitting antenna, The first scattering cluster The distance to the receiving antenna q end, The signal transmitted from the q end to the first scattering cluster at time t The distance The first scattering cluster Distance from the center of the receiving antenna;

[0073] ,

[0074] ,

[0075] in: is the first scattering cluster at time t The distance from the center of the transmitting antenna, is the first scattering cluster at time t The distance from the center of the receiving antenna, is the horizontal distance between the transmitter and the street on the right, is the moving speed of the transmitter, is the moving speed of the receiving end, is the vertical straight-line distance between the receiving end and the street below in the y-axis direction;

[0076] ,

[0077] ,

[0078] ,

[0079] in: The p-end of the transmitted signal passes through the second scattering cluster The distance The p-end of the transmitted signal at time t passes through the second scattering cluster The distance The second scattering cluster Distance from the center of the transmitting antenna; The second scattering cluster The distance to the receiving antenna q end, is the second scattering cluster at time t The distance to the receiving antenna q end; The second scattering cluster Distance from the center of the receiving antenna;

[0080] ,

[0081] ,

[0082] in: is the second scattering cluster at time t The distance from the center of the transmitting antenna, is the second scattering cluster at time t The distance from the center of the receiving antenna, Indicates the first scattering cluster in the y-axis direction The vertical straight-line distance to the street below, Indicates the vertical straight-line distance between the receiving end and the street above in the y-axis direction. is the distance between the transmitting end and the street on the right in the vertical plane;

[0083] ,

[0084] ,

[0085] ,

[0086] in, The p-end of the transmitted signal passes through the third scattering cluster The distance The p-end of the transmitted signal at time t passes through the third scattering cluster The distance The third scattering cluster The distance from the center of the transmitting antenna, The third scattering cluster The distance to the receiving antenna q end, is the third scattering cluster at time t The distance to the receiving antenna q end, The third scattering cluster Distance from the center of the receiving antenna;

[0087] ,

[0088] ,

[0089] in, is the third scattering cluster at time t The distance from the center of the transmitting antenna, is the third scattering cluster at time t The distance from the center of the receiving antenna.

[0090] Further, when the mobile transmitting end and the mobile receiving end move vertically on the road at the intersection, the signal incident angle and the transmission angle are calculated;

[0091] Transmission Path The signal transmission angle and the angle of incidence :

[0092] ,

[0093] ,

[0094] in, is the horizontal distance between the transmitter and the street on the left;

[0095] Transmission Path The signal transmission angle and the angle of incidence :

[0096] ,

[0097] r pq ., p ′ q ′ ( d T , d R , v ′ , t ) = E { H pq * ( f ′ , t ) H p ′ q ′ ( f ′ + v , t + t )} = x LOS c R c R + 1 e − j 2 π f c ( D LoS − D ′ LoS ) / c o e j 2 pt [ f T LoS cos ( α T − c T ) + f R LoS cos ( β R − c R )] + x SBT c R + 1 ∫ β T minutes m β T max m p ( β T m ) e − j 2 π f c ( D T m − D ′ T m + D R m − D ′ R m ) / c o e j 2 pt [ f m T cos ( β T m − ϕ R ) + f m R cos ( α T m − c T )] d β T m + x SBR c R + 1 ∫ β R minutes n β R max n p ( β R n ) e − j 2 π f c ( D T n − D ′ T n + D R n − D ′ R n ) / c o e j 2 pt [ f n T cos ( β R n − ϕ R ) + f n R cos ( α R n − c T )] d β R n + x SBC c R + 1 ∫ β C minutes k β C max k p ( β C k ) e − j 2 π f c ( D T k − D ′ T k + D R k − D ′ R k ) / c o e j 2 pt [ f k T cos ( β C k − ϕ R ) + f k R cos ( α C k − ϕ T )] d β C k ,

[0098] The street corner at the third scattering cluster is divided into two parts, the upper part of the path Signal transmission angle and and the angle of incidence for:

[0099] ,

[0100] ,

[0101] The lower path The signal transmission angle and and the angle of incidence for:

[0102] ,

[0103] ,

[0104] in, The third scattering cluster Corner area values ​​within the range.

[0105] Furthermore, when the transmitting end and the receiving end move vertically at the T-shaped intersection, the time-varying channel impulse response is converted into a time-varying channel impulse response function through Fourier transformation, and the statistical characteristics of the intersection street model are calculated in combination with the incident angle and the emission angle, specifically including:

[0106] When the transmitter and receiver move vertically at the T-intersection, the time-varying channel impulse response is transformed into the time-varying channel frequency response function through Fourier transformation:

[0107] ,

[0108] The space-time-frequency cross-correlation function of vertical movement at a T-intersection is: r pq . p ′ q ′ ( d T , d R , v ′ , t ′ ) = E { H pq * ( f ′ , t ) H p ′ q ′ ( f ′ + v ′ , t + t ′ )} = x LOS c R c R + 1 e − j 2 π f c ( D LOS pq − D ′ LOS pq ) / c o e j 2 π t ′ [ f T LOS cos( α T − c T ) + f R LOS cos( β R − c R )] + x SBT c R + 1 ∫ β T minutes m β T max m p ( β T m ) e − j 2 π f c ( D T m − D ′ T m + D R m − D ′ R m ) / c o e j 2 π t ′ [ f m T cos( α T m − c T ) + f m R cos( β T m − f R )] d β T m + x SBR c R + 1 ∫ β R minutes n β R max n p ( β R n ) e − j 2 π f c ( D T n − D ′ T n + D R n − D ′ R n ) / c o e j 2 π t ′ [ f n T cos( β R n − f R ) + f n R cos( α R n − c T )] d β R n + x SBC c R + 1 ∫ β C minutes k β C max k p ( β C k ) e − j 2 π f c ( D T k − D ′ T k + D R k − D ′ R k ) / c o e j 2 π t ′ [ f k T cos( β C k − f R ) + f k R cos( α C k − c T )] d β C k ,

[0109] ,

[0110] ,

[0111] ,

[0112] in, The first scattering cluster The probability density distribution of the incident angle, The second scattering cluster Probability density distribution of incident angle; The third scattering cluster The probability density distribution of the incident angle, is the average power under the line-of-sight path; The first cluster under non-line-of-sight h kl LOS ( t ′ , t ) = c R c R + 1 e − j 2 π f c t ′ LOS kl ⋅ e j [ 2 π f T LOS t cos( α T − c T ) + 2 π f R LOS t cos( β R − c R ) + i LOS ] The average power of The second cluster under non-line-of-sight The average power of The third cluster under non-line-of-sight The average power of

[0113] is the horizontal distance from the transmitter to the receiver under the line-of-sight path; It is the horizontal distance from the transmitter to the receiver after the delay in the line-of-sight path; After a delay, the signal p is transmitted to the first scattering cluster. The distance is the first scattering cluster after time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the second scattering cluster. The distance is the second scattering cluster after a time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the third scattering cluster. The distance is the third scattering cluster after time delay The distance to the receiving antenna q end;

[0114] when When , the spatial cross-correlation function of the vertical motion of the transmitter and the receiver at the T-intersection is:

[0115] ,

[0116] The time autocorrelation function of the vertical motion of the transmitter and the receiver at the T-intersection is:

[0117] ,

[0118] when When , the time-frequency cross-correlation function of the vertical motion of the transmitter and the receiver at the T-intersection is: .

[0119] The beneficial effects achieved by the present invention are as follows: the present invention provides a modeling method for a wireless propagation channel at a crossroad street, taking into account the mutual motion of a mobile transmitter (MT) and a mobile receiver (MR) and the influence of the moving direction on the statistical characteristics of the channel, and obtaining a propagation route by using the positions of the transmitter, the receiver and the scatterer; configuring a uniform linear antenna array on the transmitter and the receiver, and obtaining a non-line-of-sight reflection component and a line-of-sight component by using the geometric relationship between the transmitter, the receiver and the scatterer in the crossroad, and adding the two components to obtain a time-varying transfer function of the model, so as to study the statistical characteristics of the geometric channel model of the crossroad, thereby accurately describing the vehicle-mounted mobile communication environment.

[0120] The present invention uses the space-time-frequency cross-correlation function of a mobile vehicle when it is traveling to analyze the multi-dimensional statistical characteristics of the wireless communication channel, especially the changes and correlations of the channel in the spatial domain (antenna), temporal domain (time) and frequency domain (frequency); by understanding the relevant characteristics of the channel in time, frequency and space, it is convenient to guide the antenna arrangement design, modulation scheme selection, time-frequency scheduling and resource allocation optimization decisions of the MIMO system, thereby improving the capacity, reliability and spectrum efficiency of the system, providing an important theoretical reference and design analysis basis for channel measurement, modeling and estimation of wireless communication systems, and having important theoretical and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0121] Figure 1 It is a transmission scene of the cross street;

[0122] Figure 2 It is a cross street geometric scattering model (straight-line driving);

[0123] Figure 3 It is a cross street geometric scattering model (driving at a T-shaped intersection);

[0124] Figure 4 is the spatial cross-correlation function of the vehicle channel model under non-line-of-sight conditions (moving towards each other on a straight road);

[0125] Figure 5 is the spatial cross-correlation function of the vehicle channel model under line-of-sight conditions (moving towards each other on a straight road);

[0126] Figure 6 It is the time-frequency cross-correlation function of the channel model of cars moving towards each other under non-line-of-sight conditions (moving towards each other on a straight road);

[0127] Figure 7 is the time-frequency cross-correlation function of the vehicle channel model under line-of-sight conditions (moving towards each other on a straight road);

[0128] Figure 8 is the time autocorrelation function of the moving receiving end and the transmitting end of the car channel model with different values ​​of Rice factor (driving in a straight line);

[0129] Figure 9 is the time autocorrelation function of the mobile receiver and transmitter in the channel model of a car with different values ​​of Rice factor (driving in a straight line) traveling in the opposite direction;

[0130] Figure 10 is the spatial cross-correlation function of the cars (driving at a T-junction);

[0131] Figure 11 is the time-frequency cross-correlation function of the car (driving at a T-junction);

[0132] Figure 12is the time autocorrelation function of the car (driving at a T-junction). DETAILED DESCRIPTION

[0133] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0134] like Figure 1~3 An embodiment shown in the figure proposes a method for modeling a wireless signal propagation channel at a crossroad, including: constructing a crossroad geometric channel model according to the crossroad street size;

[0135] The intersection geometric channel model is divided into several scatterers, and the moving vehicles in the intersection geometric channel model are divided into transmitters and receivers; a rectangular coordinate system is established with the receiver as the origin, and the propagation link is obtained through the positions of the transmitter, receiver and scatterer in the coordinate system. The time-varying channel impulse response of the intersection geometric channel model is calculated by the signal from the transmitter to the receiver through the line-of-sight path or non-line-of-sight path of the propagation link; according to the positional relationship between the transmitter and the receiver, the incident angle and emission angle of the signal in the horizontal and vertical planes are calculated; the time-varying channel impulse response is converted into a time-varying channel frequency response function through Fourier transformation, and the statistical characteristics of the intersection street model are calculated in combination with the incident angle and emission angle; the incident angle and emission angle are obtained through the geometric relationship in the cross street scattering scene and the trigonometric identity, and the time-varying transfer function of the model is further improved, and the expected value calculation of the transfer function of any two antenna propagation paths is performed to obtain the line-of-sight and non-line-of-sight space-time-frequency cross-correlation functions.

[0136] The intersection geometric channel model includes: the transmitting end and the receiving end move toward each other on a straight road or the transmitting end and the receiving end move vertically at a T-shaped intersection; when the transmitting end and the receiving end move toward each other on a straight road, their scatterers are evenly distributed on the street, which are street scatterers; when the transmitting end and the receiving end move vertically at a T-shaped intersection, the scatterers are distributed at street corners, which are street corner scattering clusters.

[0137] When the transmitting end and the receiving end move toward each other on a straight road, the time-varying channel impulse response of the calculation of the intersection geometric channel model specifically includes:

[0138] Time-varying channel impulse response The calculation process is:

[0139]

[0140] in: is the delay, t is the time, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the line-of-sight component, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path; is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path;

[0141] h kl LOS ( t ′ , t ) = c R c R + 1 e − j 2 π f c t ′ LOS kl ⋅ e j [ 2 π f T LOS t cos( α T − c T ) + 2 π f R LOS t cos( β R − c R ) + i LOS ] , ,

[0142] ,

[0143] Where j is the imaginary unit, is the Rice factor; is the carrier frequency; , , are independently distributed random variables in the interval ( 0 , 2 π ] Follow uniform distribution;

[0144] is the signal emission angle, is the signal incident angle, is the angle of the transmitting antenna in the xy plane relative to the x-axis direction, is the angle of the receiving antenna in the xy plane relative to the x-axis direction;

[0145] is the Doppler shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler frequency shift caused by the motion of the receiver under the line-of-sight path, ; is the Doppler shift caused by the movement of the transmitter in the non-line-of-sight path, ; is the Doppler shift caused by the movement of the receiving end in the non-line-of-sight path, ; is the angle between the transmitting end's motion direction and the x-axis, is the angle between the receiving end's moving direction and the x-axis, is the moving speed of the transmitter, is the moving speed of the receiving end; For the line-of-sight component signal, the transmission link The propagation delay of For the line-of-sight component signal, the transmission link Propagation delay, For the line-of-sight component signal, the transmission link The propagation delay of is a street scatterer, is the kth transmitting antenna element at the transmitting end, is the lth transmitting antenna element at the receiving end; M is the total number of street scatterers on the x-axis side, m is the mth street scatterer on the x-axis side, N is the total number of street scatterers on the y-axis side, n is the nth street scatterer on the y-axis side;

[0146] ,

[0147] ,

[0148] ,

[0149] ,

[0150] ,

[0151] ,

[0152] ,

[0153] ,

[0154] in: is the speed of light, (x, y) is the scatterer in the rectangular coordinate system The location coordinates of

[0155] For signals propagating over line-of-sight links The distance, x R is the distance of the receiving end on the x-axis, x T is the distance of the transmitter on the x-axis, y R is the distance of the receiving end on the y axis, y T is the distance of the transmitter on the y axis;

[0156] The distance from the transmitter to the street scatterer in the non-line-of-sight transmission link The distance The distance from the transmitting signal antenna k to the street scatterer in the non-line-of-sight transmission link The distance, M T is the number of transmitting antennas, is the spacing between the transmitting antenna elements;

[0157] Street scatterers in non-line-of-sight links The distance to the receiving end, Street scatterers in non-line-of-sight links The distance to the receiving antenna L, M R is the number of antennas at the receiving end, is the spacing between antenna elements at the receiving end.

[0158] Furthermore, when the transmitting end and the receiving end move toward each other on a straight road, the incident angle and the emission angle of the signal in the horizontal plane and the vertical plane specifically include the following steps:

[0159] ,

[0160] ,

[0161] in, ,when hour J 1 = [ w b , R ] ,when hour, J 2 = [ − R , − w m − w n ] , i is the intermediate variable taken to simplify the formula, D 1 is the horizontal straight line distance between the receiving end and the transmitting end in the x-axis direction, R is the radius of the circular street with the receiving end as the origin, and w m is the vertical distance between the transmitter and the receiver on the x-axis, w n is the vertical straight-line distance between the transmitter and the street in the y-axis direction, w b When the vehicles move in a straight line towards each other, the distance between the receiving end and the left side of the road, w c is the vertical distance between the right corner of the transmitting end and the receiving end on the y-axis, w x It is the vertical distance of the road perpendicular to the direction of the vehicle's straight-line movement.

[0162] When the transmitting end and the receiving end move toward each other on a straight road, the method of converting the time-varying channel impulse response into a time-varying channel frequency response function through Fourier transform and calculating the statistical characteristics of the intersection street model in combination with the incident angle and the emission angle specifically includes the following steps:

[0163] When the transmitter and the receiver move towards each other on a straight road, the time-varying channel impulse response is transformed into the time-varying channel frequency response function through Fourier transformation:

[0164] ,

[0165] in: for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function;

[0166] The space-time-frequency cross-correlation function when driving on a straight road is:

[0167] ,

[0168] in: is the Doppler shift, is the carrier frequency of the signal, (*) is the complex conjugate, and E{.} is the expectation operator;

[0169] The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is:

[0170] ,

[0171] in,

[0172] ,

[0173] ,

[0174] in, is the time delay of the propagation path of the non-line-of-sight reflection component. The average processing result is and For the receiving end and Antennas and ≠ , and The transmitter and Antennas and ≠ ; and To simplify the formula, we use the intermediate variables: The transmitting end is affected by street scatterers The Doppler frequency caused by the impact;

[0175] The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is:

[0176] ,

[0177] ,

[0178] ,

[0179] ,

[0180] in, and Intermediate variables taken to simplify the formula; is the probability density distribution of the incident angle, and it obeys the von Mises distribution, is the zero-order modified Bessel function, represents a measure of concentration, is the average value of the receiving angle, when As time goes to infinity, That is the Gaussian distribution;

[0181] The spatial-temporal-frequency cross-correlation function of the line-of-sight component is:

[0182] ,

[0183] in, is the time delay of the line-of-sight reflection component propagation path, is the Ricean factor of the sight-range component;

[0184] when When , the spatial cross-correlation function between the transmitter and the receiver when traveling on a straight road is:

[0185] ,

[0186] The time autocorrelation function of the transmitter and receiver when traveling on a straight road is:

[0187] .

[0188] Calculate the time-varying channel impulse response of the intersection geometric channel model when the transmitter and receiver move vertically at the T-intersection Specifically include:

[0189] ,

[0190] in: is the impulse response function from the pth transmitting antenna element at the transmitting end to the qth receiving antenna element at the receiving end under the signal line-of-sight component, The signal non-line-of-sight component passes through the first street corner scattering cluster The impulse response of The signal non-line-of-sight component passes through the second street corner scattering cluster The impulse response of The non-line-of-sight component of the signal passes through the third street corner scattering cluster The impulse response of , h pq SBT ( t ) = lim M →∞ 1 ( c R + 1 ) M ∑ m = 1 M e − j 2 π f c t ′ m e j [ 2 π f m T t cos( α T m − f T ) + 2 π f m R t cos( β T m − f R ) + i m ] ,

[0191] h pq SBR ( t ′ , t ) = lim N →∞ 1 ( c R + 1 ) N ∑ n = 1 N e − j 2 π f c t ′ n e j [ 2 π f n T t cos( α R n − f T ) + 2 π f n R t cos( β R n − f R ) + i n ] ,

[0192] h pq SBC ( t ′ , t ) = lim K →∞ 1 ( c R + 1 ) K ∑ k = 1 K e − j 2 π f c t ′ k e j [ 2 π f k T t cos( α C k − f T ) + 2 π f k R t cos( β C k − f R ) + i k ] ,

[0193] in: is the emission angle of the line-of-sight component, is the incident angle of the sight component, is the phase of the line-of-sight component; The non-line-of-sight component signal passes through the first scattering cluster Emission angle, The non-line-of-sight component signal passes through the first scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the second scattering cluster Emission angle, The non-line-of-sight component signal passes through the second scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the third scattering cluster Emission angle, The non-line-of-sight component signal passes through the third scattering cluster Angle of incidence; The signal passes through the first scattering cluster The phase at a particular moment caused by The signal passes through the second scattering cluster The phase at a particular moment caused by The signal passes through the third scattering cluster The phase at a specific moment caused by are all independently distributed random variables in the interval ( 0 , 2 π ] Follow uniform distribution; is the Doppler shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler shift caused by the motion of the receiving end in the line-of-sight path, ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The path that the line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of

[0194] ,

[0195] ,

[0196] in: The path from the transmitter to the receiver of the line-of-sight component signal The distance

[0197] ,

[0198] ,

[0199] ,

[0200] in: To transmit the signal p to the first scattering cluster The distance The signal transmitted from the p end to the first scattering cluster at time t The distance The first scattering cluster The distance from the center of the transmitting antenna,

[0201] The first scattering cluster The distance to the receiving antenna q end, The signal transmitted from the q end to the first scattering cluster at time t The distance The first scattering cluster Distance from the center of the receiving antenna;

[0202] ,

[0203] ,

[0204] in: is the first scattering cluster at time t The distance from the center of the transmitting antenna, is the first scattering cluster at time t The distance from the center of the receiving antenna, is the horizontal distance between the transmitter and the street on the right, is the moving speed of the transmitter, is the moving speed of the receiving end, is the vertical straight-line distance between the receiving end and the street below in the y-axis direction;

[0205] ,

[0206] ,

[0207] ,

[0208] in: The p-end of the transmitted signal passes through the second scattering cluster The distance The p-end of the transmitted signal at time t passes through the second scattering cluster The distance The second scattering cluster Distance from the center of the transmitting antenna; The second scattering cluster The distance to the receiving antenna q end, is the second scattering cluster at time t The distance to the receiving antenna q end; The second scattering cluster Distance from the center of the receiving antenna;

[0209] ,

[0210] ,

[0211] in: is the second scattering cluster at time t The distance from the center of the transmitting antenna, is the second scattering cluster at time t The distance from the center of the receiving antenna, Indicates the first scattering cluster in the y-axis direction The vertical straight-line distance to the street below, Indicates the vertical straight-line distance between the receiving end and the street above in the y-axis direction. is the distance between the transmitting end and the street on the right in the vertical plane;

[0212] ,

[0213] ,

[0214] ,

[0215] in, The p-end of the transmitted signal passes through the third scattering cluster The distance The p-end of the transmitted signal at time t passes through the third scattering cluster The distance The third scattering cluster The distance from the center of the transmitting antenna, The third scattering cluster The distance to the receiving antenna q end, is the third scattering cluster at time t The distance to the receiving antenna q end, The third scattering cluster Distance from the center of the receiving antenna;

[0216] ,

[0217] ,

[0218] in, is the third scattering cluster at time t The distance from the center of the transmitting antenna, is the third scattering cluster at time t The distance from the center of the receiving antenna.

[0219] Further, when the mobile transmitting end and the mobile receiving end move vertically on the road at the intersection, the signal incident angle and the transmission angle are calculated;

[0220] Transmission Path The signal transmission angle and the angle of incidence :

[0221] ,

[0222] ,

[0223] in, is the horizontal distance between the transmitter and the street on the left;

[0224] Transmission Path The signal transmission angle and the angle of incidence

[0225] ,

[0226] r pq ., p ′ q ′ ( d T , d R , v ′ , t ) = E { H pq * ( f ′ , t ) H p ′ q ′ ( f ′ + v , t + t )} = x LOS c R c R + 1 e − j 2 π f c ( D LoS − D ′ LoS ) / c o e j 2 pt [ f T LoS cos ( α T − c T ) + f R LoS cos ( β R − c R )] + x SBT c R + 1 ∫ β T minutes m β T max m p ( β T m ) e − j 2 π f c ( D T m − D ′ T m + D R m − D ′ R m ) / c o e j 2 pt [ f m T cos ( β T m − ϕ R ) + f m R cos ( α T m − c T )] d β T m + x SBR c R + 1 ∫ β R minutes n β R max n p ( β R n ) e − j 2 π f c ( D T n − D ′ T n + D R n − D ′ R n ) / c o e j 2 pt [ f n T cos ( β R n − ϕ R ) + f n R cos ( α R n − c T )] d β R n + x SBC c R + 1 ∫ β C minutes k β C max k p ( β C k ) e − j 2 π f c ( D T k − D ′ T k + D R k − D ′ R k ) / c o e j 2 pt [ f k T cos ( β C k − ϕ R ) + f k R cos ( α C k − ϕ T )] d β C k ,

[0227] The street corner at the third scattering cluster is divided into two parts, the upper part of the path Signal transmission angle and and the angle of incidence for:

[0228] ,

[0229] ,

[0230] The lower path The signal transmission angle and and the angle of incidence for:

[0231] ,

[0232] ,

[0233] in, The third scattering cluster Corner area values ​​within the range.

[0234] When the transmitting end and the receiving end move vertically at the T-shaped intersection, the time-varying channel impulse response is converted into a time-varying channel impulse response function through Fourier transformation, and the statistical characteristics of the intersection street model are calculated in combination with the incident angle and the emission angle. Specifically, the method includes:

[0235] When the transmitter and receiver move vertically at the T-intersection, the time-varying channel impulse response is transformed into the time-varying channel frequency response function through Fourier transformation:

[0236] ,

[0237] The space-time-frequency cross-correlation function of vertical movement at a T-intersection is: r pq . p ′ q ′ ( d T , d R , v ′ , t ′ ) = E { H pq * ( f ′ , t ) H p ′ q ′ ( f ′ + v ′ , t + t ′ )} = x LOS c R c R + 1 e − j 2 π f c ( D LOS pq − D ′ LOS pq ) / c o e j 2 π t ′ [ f T LOS cos( α T − c T ) + f R LOS cos( β R − c R )] + x SBT c R + 1 ∫ β T minutes m β T max m p ( β T m ) e − j 2 π f c ( D T m − D ′ T m + D R m − D ′ R m ) / c o e j 2 π t ′ [ f m T cos( α T m − c T ) + f m R cos( β T m − f R )] d β T m + x SBR c R + 1 ∫ β R minutes n β R max n p ( β R n ) e − j 2 π f c ( D T n − D ′ T n + D R n − D ′ R n ) / c o e j 2 π t ′ [ f n T cos( β R n − f R ) + f n R cos( α R n − c T )] d β R n + x SBC c R + 1 ∫ β C minutes k β C max k p ( β C k ) e − j 2 π f c ( D T k − D ′ T k + D R k − D ′ R k ) / c o e j 2 π t ′ [ f k T cos( β C k − f R ) + f k R cos( α C k − c T )] d β C k ,

[0238] in,

[0239] ,

[0240] ,

[0241] ,

[0242] in, The first scattering cluster The probability density distribution of the incident angle, The second scattering cluster Probability density distribution of incident angle; The third scattering cluster The probability density distribution of the incident angle, is the average power under the line-of-sight path; The first cluster under non-line-of-sight h kl LOS ( t ′ , t ) = c R c R + 1 e − j 2 π f c t ′ LOS kl ⋅ e j [ 2 π f T LOS t cos( α T − c T ) + 2 π f R LOS t cos( β R − c R ) + i LOS ] The average power of The second cluster under non-line-of-sight The average power of The third cluster under non-line-of-sight The average power of

[0243] is the horizontal distance from the transmitter to the receiver under the line-of-sight path; It is the horizontal distance from the transmitter to the receiver after the delay in the line-of-sight path; After a delay, the signal p is transmitted to the first scattering cluster. The distance is the first scattering cluster after time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the second scattering cluster. The distance is the second scattering cluster after a time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the third scattering cluster. The distance is the third scattering cluster after time delay The distance to the receiving antenna q end;

[0244] when When , the spatial cross-correlation function of the vertical motion of the transmitter and the receiver at the T-intersection is:

[0245] ,

[0246] The time autocorrelation function of the vertical motion of the transmitter and the receiver at the T-intersection is:

[0247] ,

[0248] when When , the time-frequency cross-correlation function of the vertical motion of the transmitter and the receiver at the T-intersection is: .

[0249] Modeling and statistical characteristics analysis of cross street wireless propagation channels,

[0250] like Figure 4 As shown, Simulation diagram of the two-dimensional spatial reference model in the non-line-of-sight situation. During the NLOS transmission process where the plane wave passes from the transmitting antenna to the receiving antenna via the scatterer, the linear array spacing It reaches a maximum value of 1 when , and decreases with the increase of antenna spacing. Therefore, the correlation can be reduced by increasing the antenna unit spacing; therefore, a greater capacity gain can be obtained by changing the antenna spacing.

[0251] like Figure 5 As shown, The simulation diagram of the two-dimensional reference model under the LOS condition. After comparison, it can be known that the two-dimensional space S-CCF changes with the Rice factor And the simulation results are close to the spatial cross-correlation function in Avazov, which proves the reliability of this model.

[0252] like Figure 6~7 As shown, When the time-frequency cross-correlation function takes a value of 0 or 2, we can see from the figure that when When TF-CCF reaches the maximum value of 1, the cross-correlation function gradually decreases with the increase of delay and frequency, and fluctuates slightly in the stable state.

[0253] like Figure 8~9 As shown in the figure, the influence of different Rice factors on the time autocorrelation function is compared. Figure 8 and 9 ) can be found in reverse driving ( , ) When the oscillation frequency under line-of-sight conditions is higher than that under non-line-of-sight conditions, the autocorrelation function increases with The transmitter and receiver travel in the same direction ( ) As the distance increases, the path traversed by the plane wave increases and the time autocorrelation function decreases.

[0254] Figure 10 This is a simulation diagram of the reference model of the two-dimensional spatial cross-correlation function. It can be seen from the figure that when the antenna unit spacing When S-CCF reaches its maximum value, it decreases with the increase of spacing and finally tends to be stable.

[0255] Figure 11 This is a simulation diagram of the reference model of the two-dimensional spatial cross-correlation function. This result is consistent with Figure 7 The simulation results of the time-frequency cross-correlation function in are similar.

[0256] Figure 12The influence of the distance between the transmitter and the receiver on the time autocorrelation function is shown in Figure 2. Figure 12 It can be seen that within the time delay of 0.01s, the ACF decreases quickly. When the distance between the transmitter and the receiver increases, the signal path from the transmitter to the receiver increases, resulting in a decrease in ACF. The figure shows the ACF distribution trend of CHELLI A in a similar T-shaped intersection model. It can be seen that the autocorrelation degree of this model is lower and more suitable for describing the intersection scene, which further verifies the rationality and feasibility of the proposed model to describe the intersection street.

[0257] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

Claims

1. A method for modeling a wireless propagation channel at a crossroad street, characterized in that: include: According to the street dimensions of the intersection, a geometric channel model of the intersection is constructed; The intersection geometric channel model is divided into several scatterers, and the moving vehicles in the intersection geometric channel model are divided into transmitting ends and receiving ends; A rectangular coordinate system is established with the receiving end as the origin, and the propagation link is obtained through the positions of the transmitting end, the receiving end and the scatterer in the coordinate system. The time-varying channel impulse response of the intersection geometric channel model is calculated by the signal from the transmitting end to the receiving end through the line-of-sight path or non-line-of-sight path of the propagation link; According to the positional relationship between the transmitting end and the receiving end, the incident angle and the emission angle of the signal in the horizontal plane and the vertical plane are calculated; The time-varying channel impulse response is transformed into a time-varying channel frequency response function through Fourier transform, and the statistical characteristics of the intersection street model are calculated by combining the incident angle and the emission angle.

2. The method for modeling a wireless propagation channel at a crossroad according to claim 1, characterized in that: The intersection geometric channel model includes: the transmitting end and the receiving end move towards each other on a straight road or the transmitting end and the receiving end move vertically at a T-shaped intersection; When the transmitter and receiver move toward each other on a straight road, their scatterers are evenly distributed on the street, which are street scatterers; when the transmitter and receiver move vertically at a T-intersection, the scatterers are distributed at the street corners, which are street corner scattering clusters.

3. The method for modeling a wireless propagation channel at a crossroad according to claim 2, characterized in that: When the transmitting end and the receiving end move toward each other on a straight road, the time-varying channel impulse response of the calculation of the intersection geometric channel model specifically includes: Time-varying channel impulse response The calculation process is: ， in: is the delay, t is the time, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the line-of-sight component, is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path; is the impulse response function from the kth transmitting antenna element at the transmitting end to the lth receiving antenna element at the receiving end under the non-line-of-sight propagation path; ， ， ， Where j is the imaginary unit, is the Rice factor; is the carrier frequency; , , are independently distributed random variables in the interval Follow uniform distribution; is the signal emission angle, is the signal incident angle, is the angle of the transmitting antenna in the xy plane relative to the x-axis direction, is the angle of the receiving antenna in the xy plane relative to the x-axis direction; is the Doppler frequency shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler frequency shift caused by the motion of the receiver under the line-of-sight path, ; is the Doppler shift caused by the movement of the transmitter in the non-line-of-sight path, ; is the Doppler shift caused by the movement of the receiving end in the non-line-of-sight path, ; is the angle between the transmitting end's motion direction and the x-axis, is the angle between the receiving end's moving direction and the x-axis, is the moving speed of the transmitter, is the moving speed of the receiving end; For the line-of-sight component signal, the transmission link The propagation delay of The line-of-sight component signal passes through the propagation link Propagation delay, For the line-of-sight component signal, the transmission link The propagation delay of is a street scatterer, is the kth transmitting antenna element at the transmitting end, is the lth transmitting antenna element at the receiving end; M is the total number of street scatterers on the x-axis side, m is the mth street scatterer on the x-axis side, N is the total number of street scatterers on the y-axis side, n is the nth street scatterer on the y-axis side; ， ， ， ， ， ， ， ， in: is the speed of light, (x, y) is the scatterer in the rectangular coordinate system The location coordinates of For signals propagating over line-of-sight links The distance, x R is the distance of the receiving end on the x-axis, x T is the distance of the transmitter on the x-axis, y R is the distance of the receiving end on the y axis, y T is the distance of the transmitter on the y axis; The distance from the transmitter to the street scatterer in the non-line-of-sight transmission link The distance The distance from the transmitting signal antenna k to the street scatterer in the non-line-of-sight transmission link The distance, M T is the number of transmitting antennas, is the spacing between the transmitting antenna elements; Street scatterers in non-line-of-sight links The distance to the receiving end, Street scatterers in non-line-of-sight links The distance to the receiving antenna L, M R is the number of antennas at the receiving end, is the spacing between antenna elements at the receiving end.

4. The method for modeling a wireless propagation channel at a crossroad according to claim 3, characterized in that: When the transmitting end and the receiving end move toward each other on a straight road, the incident angle and the emission angle of the signal in the horizontal plane and the vertical plane specifically include the following steps: ， ， in, ,when hour ,when hour, , i is the intermediate variable taken in the simplified formula, D1 is the horizontal straight-line distance between the receiving end and the transmitting end in the x-axis direction, R is the radius of the circular street with the receiving end as the origin, and w m is the vertical distance between the transmitter and the receiver on the x-axis, w n is the vertical straight-line distance between the transmitter and the street in the y-axis direction, w b When the vehicles move in a straight line towards each other, the distance between the receiving end and the left side of the road, w c is the vertical distance between the right corner of the transmitting end and the receiving end on the y-axis, w x It is the vertical distance of the road perpendicular to the direction of the vehicle's straight-line movement.

5. The method for modeling a wireless propagation channel at a crossroad according to claim 4, characterized in that: When the transmitting end and the receiving end move toward each other on a straight road, the method of converting the time-varying channel impulse response into a time-varying channel frequency response function through Fourier transform and calculating the statistical characteristics of the intersection street model in combination with the incident angle and the emission angle specifically includes the following steps: When the transmitter and the receiver move towards each other on a straight road, the time-varying channel impulse response is transformed into the time-varying channel frequency response function through Fourier transformation: ， in: for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function, for Fourier transform to time-varying channel frequency response function; The space-time-frequency cross-correlation function when driving on a straight road is: ， in: is the Doppler shift, is the carrier frequency of the signal, (*) is the complex conjugate, and E{⋅} is the expected operator; The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is: ， in, ， ， in, is the time delay of the propagation path of the non-line-of-sight reflected component, and For the receiving end and Antennas and ≠ , and The transmitter and Antennas and ≠ ; and To simplify the formula, we use the intermediate variables: The transmitting end is affected by street scatterers The Doppler frequency caused by the impact; The spatial-temporal-frequency cross-correlation function of the non-line-of-sight reflection component is: ， ， ， ， in, and Intermediate variables taken to simplify the formula; is the probability density distribution of the incident angle, and it obeys the von Mises distribution, is the zero-order modified Bessel function, represents a measure of concentration, is the average value of the receiving angle, when As time goes to infinity, That is the Gaussian distribution; The spatial-temporal-frequency cross-correlation function of the line-of-sight component is: ， in, is the time delay of the line-of-sight reflection component propagation path, is the Ricean factor of the sight-range component; when When , the spatial cross-correlation function between the transmitter and the receiver when traveling on a straight road is: ， The time autocorrelation function of the transmitter and receiver when traveling on a straight road is: 。 6. The method for modeling a wireless propagation channel at a crossroad according to claim 2, characterized in that: Calculate the time-varying channel impulse response of the intersection geometric channel model when the transmitter and receiver move vertically at the T-intersection Specifically include: ， in: is the impulse response function from the pth transmitting antenna element at the transmitting end to the qth receiving antenna element at the receiving end under the signal line-of-sight component, The signal non-line-of-sight component passes through the first street corner scattering cluster The impulse response of The signal non-line-of-sight component passes through the second street corner scattering cluster The impulse response of The non-line-of-sight component of the signal passes through the third street corner scattering cluster The impulse response of ， ， ， ， in: is the emission angle of the line-of-sight component, is the incident angle of the sight component, is the phase of the line-of-sight component; The non-line-of-sight component signal passes through the first scattering cluster Emission angle, The non-line-of-sight component signal passes through the first scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the second scattering cluster Emission angle, The non-line-of-sight component signal passes through the second scattering cluster Angle of incidence, The non-line-of-sight component signal passes through the third scattering cluster Emission angle, The non-line-of-sight component signal passes through the third scattering cluster Angle of incidence; The signal passes through the first scattering cluster The phase at a particular moment caused by The signal passes through the second scattering cluster The phase at a particular moment caused by The signal passes through the third scattering cluster The phase at a specific moment caused by are all independently distributed random variables in the interval Follow uniform distribution; is the Doppler shift caused by the motion of the transmitter in the line-of-sight path, ; is the Doppler shift caused by the motion of the receiving end in the line-of-sight path, ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the first scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the second scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the transmitter is ; The non-line-of-sight path signal passes through the third scattering cluster The Doppler frequency shift caused by the motion of the receiving end is ; The path that the line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of The path that the non-line-of-sight component signal takes from the transmitter to the receiver The propagation delay of ， ， in: The path from the transmitter to the receiver of the line-of-sight component signal The distance ， ， ， in: To transmit the signal p to the first scattering cluster The distance The first scattering cluster The distance from the center of the transmitting antenna, The first scattering cluster The distance to the receiving antenna q end, The first scattering cluster Distance from the center of the receiving antenna; ， ， in: is the horizontal distance between the transmitter and the street on the right, is the moving speed of the transmitter, is the moving speed of the receiving end, is the vertical straight-line distance between the receiving end and the street below in the y-axis direction; ， ， ， in: The p-end of the transmitted signal passes through the second scattering cluster The distance The second scattering cluster The distance from the center of the transmitting antenna, The second scattering cluster The distance to the receiving antenna q end, The second scattering cluster Distance from the center of the receiving antenna; ， ， in: Indicates the first scattering cluster in the y-axis direction The vertical straight-line distance to the street below, Indicates the vertical straight-line distance between the receiving end and the street above in the y-axis direction. is the distance between the transmitting end and the street on the right in the vertical plane; ， ， ， ， ， in, The p-end of the transmitted signal passes through the third scattering cluster The distance The third scattering cluster The distance from the center of the transmitting antenna, The third scattering cluster The distance to the receiving antenna q end, The third scattering cluster The distance from the center of the receiving antenna.

7. The method for modeling a wireless propagation channel at a crossroad according to claim 6, characterized in that: When the mobile transmitter and the mobile receiver move vertically on the intersection road, calculate the signal incident angle and emission angle; propagation path The signal transmission angle and the angle of incidence : ， ， in, is the horizontal distance between the transmitter and the street on the left; Transmission Path The signal transmission angle and the angle of incidence for: ， ， The street corner at the third scattering cluster is divided into two parts, the upper part of the path Signal transmission angle and and the angle of incidence for: ， ， The lower path The signal transmission angle and and the angle of incidence for: ， ， in, The third scattering cluster Corner area values ​​within the range.

8. The method for modeling a wireless propagation channel at a crossroad according to claim 7, characterized in that: When the transmitting end and the receiving end move vertically at the T-shaped intersection, the time-varying channel impulse response is transformed into a time-varying channel impulse response function by Fourier transform, and the statistical characteristics of the intersection street model are calculated by combining the incident angle and the transmission angle. Specifically, when the transmitting end and the receiving end move vertically at the T-shaped intersection, the time-varying channel impulse response is transformed into a time-varying channel frequency response function by Fourier transform: ， The space-time-frequency cross-correlation function of vertical movement at a T-intersection is: ， in, ， ， ， in, The first scattering cluster The probability density distribution of the incident angle, The second scattering cluster Probability density distribution of incident angle; The third scattering cluster The probability density distribution of the incident angle, is the average power under the line-of-sight path; The first cluster under non-line-of-sight The average power of The second cluster under non-line-of-sight The average power of The third cluster under non-line-of-sight The average power of is the horizontal distance from the transmitter to the receiver under the line-of-sight path; It is the horizontal distance from the transmitter to the receiver after the delay in the line-of-sight path; After a delay, the signal p is transmitted to the first scattering cluster. The distance is the first scattering cluster after time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the second scattering cluster. The distance is the second scattering cluster after a time delay The distance to the receiving antenna q end; After a delay, the signal p is transmitted to the third scattering cluster. The distance is the third scattering cluster after time delay The distance to the receiving antenna q end; when When , the spatial cross-correlation function of the vertical motion of the transmitter and the receiver at the T-intersection is: ， The temporal autocorrelation function of the vertical motion of the transmitter and receiver at the T-intersection is: 。

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