Anti-doppler-frequency-shift near-field wireless communication beamforming method for internet of vehicles

Abstract

An anti-Doppler-frequency-shift near-field wireless communication beamforming method for the Internet of Vehicles. The method comprises: 1) determining boundaries of a far-field area and a near-field area in a coverage area; 2) determining whether a mobile terminal is located within the near-field area; 3) determining the distance from a vehicle to the center of an antenna array, the complementary angle of the included angle between the vehicle and the plane of the antenna array, and the speed of the vehicle traveling along a straight line; 4) determining the distance L(x,y) between the moving vehicle and each antenna unit in the super-large-scale antenna array of a base station; 5) determining a channel expression from each antenna unit in the super-large-scale antenna array of the base station to the moving vehicle; 6) adjusting beamforming parameters, and performing beamforming control on array antennas; and 7) updating information on the basis of the periodic location of the mobile terminal. The method is a near-field wireless communication beamforming method based on a super-large-scale array antenna, and enhances the data transmission guarantee for the Internet of Vehicles in an urban environment.

Description

A Doppler-shift-resistant near-field wireless communication beamforming method for connected vehicles Technical Field

[0001] The present invention relates to a Doppler shift-resistant near-field wireless communication beamforming method for an Internet of Vehicles (IoV), and belongs to the technical field of wireless communication. Background Art

[0002] Faced with the rapidly growing demand for data services in wireless communication systems, millimeter-wave communication technology, leveraging its large bandwidth, can meet the need for high-speed, low-latency communications. Millimeter-wave communication technology is one of the core technologies in current wireless communications. Its abundant spectrum resources enable ultra-high data transmission rates and a wide range of application scenarios, making it a research hotspot in both industry and academia. However, the ultra-high frequency of millimeter waves and various factors in the transmission environment can cause severe path loss and limited coverage. By deploying ultra-large-scale antenna arrays at base stations and user terminals, and designing appropriate and effective beamforming parameter adjustment schemes, path loss can be effectively compensated for and communication quality can be improved. The introduction of millimeter-wave technology in urban transportation communication environments can help address communication quality issues between vehicles and between vehicles and base stations.

[0003] However, the deployment of ultra-large-scale antenna arrays expands the near-field region of radio wave propagation, placing users frequently within this region. This requires analysis and processing based on the characteristics of near-field spherical waves, rather than the approximate plane wave analysis and design used in the far-field region. Furthermore, urban traffic communication scenarios present significant Doppler shift issues. The high mobility of vehicles generates Doppler shift in radio waves, causing rapid channel changes and leading to unstable channel gain, thus impacting data transmission.

[0004] Therefore, in order to study the superposition effect of the angle and distance of the incoming wave brought about by the above-mentioned near-field spherical wave transmission characteristics and high mobility, it is necessary to study the near-field beamforming with Doppler shift resistance of the Internet of Vehicles to ensure that the base station transmits a high-gain signal beam to the target vehicle, improve the data transmission quality between the base station and the vehicle, and ensure highly reliable and low-latency communication services.

[0005] Patent publication number CN10707-0818B, "Doppler frequency offset estimation method and apparatus based on millimeter wave MIMO system," proposes a Doppler frequency offset estimation scheme based on a maximum likelihood estimation model. Using the signal acquired at the receiving end of the millimeter wave system as the model input, the model derives an expression for the Doppler frequency shift estimate. Patent publication number CN11110-6859B, "Millimeter wave / terahertz network massive MIMO wireless transmission method," synchronizes the acquired signal in time and frequency at the receiving end and utilizes a deterministic equivalence method to determine the optimal power allocation matrix to mitigate the transmission performance degradation caused by multipath and Doppler effects. However, these works do not consider the near-field communication issues presented by ultra-large-scale antenna arrays or the Doppler frequency shift caused by the high mobility of vehicles in complex urban environments.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to address the defects and shortcomings of the above-mentioned prior art and propose a near-field wireless communication beamforming method that is resistant to Doppler shift for vehicle networks, which is used for communication transmission between highly mobile vehicles and fixed base stations in complex urban environments. While effectively overcoming Doppler shift, this method can accurately achieve near-field beamforming, improve the data transmission quality between base stations and vehicles, and is beneficial for vehicles in urban environments to obtain high-quality communication services while driving, and is also beneficial to the safe and stable operation of urban transportation communication networks.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a near-field wireless communication beamforming method with Doppler shift resistance for the Internet of Vehicles, the method comprising the following steps:

[0009] Step 1: Each base station in an urban environment is equipped with a large-scale uniform circular antenna array. The boundaries D of the far and near fields in the coverage area are determined based on the antenna array characteristic parameters.

[0010] Step 2: When a vehicle in an urban environment is within the coverage area of ​​the base station, the mobile terminal updates its location information to the base station via a reverse link. The base station determines whether the mobile terminal is within the near-field area based on the location information. If so, it proceeds to the next step. If not, it repeats step 2.

[0011] Step 3: When a moving vehicle in an urban environment is in the near field of the base station, the base station determines the distance l from the vehicle to the center of the antenna array, the complementary angle θ between the vehicle and the antenna array plane, and the vehicle's speed v along a straight line based on the vehicle's location information.

[0012] Step 4: Based on the relevant parameters of the mobile vehicle, including the distance l and the angle θ, determine the distance L(x,y) between the mobile vehicle and each antenna element in the base station's very large-scale antenna array, where x represents the component of the antenna element on the x-axis in the plane where the very large-scale circular antenna is located, and y represents the component of the antenna element on the y-axis in the plane where the very large-scale circular antenna is located;

[0013] Step 5: Based on the near-field channel model of the Internet of Vehicles, determine the channel expression from each antenna unit in the base station's ultra-large-scale antenna array to the mobile vehicle;

[0014] Step 6: The base station adjusts the beamforming parameters according to the channel expression and performs beamforming control on the array antenna based on the adjusted parameters;

[0015] Step 7: Based on the periodic location update information of the mobile terminal, if yes, jump to the above step 2, if not, repeat step 7.

[0016] Furthermore, in step 1, the calculation formula for the far-field and near-field boundaries D in the coverage area is as follows:

[0017] Where R represents the radius of the ultra-large-scale circular antenna array at the base station, λ C Indicates the carrier wavelength of a communication system.

[0018] Furthermore, in step 4, the distance between the mobile vehicle and the antenna units in the base station's ultra-large-scale antenna array is calculated as follows:

[0019] Among them, x i represents the component of the ith antenna unit on the x-axis in the plane where the ultra-large-scale circular antenna is located, and x∈[x min ,x max ], y i represents the component of the ith antenna unit on the y-axis in the plane where the ultra-large-scale circular antenna is located, and y∈[y min ,y max ], σ represents the distance added by the vehicle during the movement, and its calculation formula is as follows:

[0020] σ=vt Equation 3

[0021] Among them, v represents the vehicle speed and t represents the vehicle travel time.

[0022] Furthermore, in step 5, at time t, when the frequency is f, the channel from the i-th antenna unit in the base station's ultra-large-scale antenna array to the mobile vehicle is obtained by the following formula:

[0023] Among them, x irepresents the component of the i-th antenna unit on the x-axis in the plane where the ultra-large-scale circular antenna is located, y i represents the component of the ith antenna element on the y-axis in the plane where the ultra-large-scale circular antenna is located, N t represents the number of antennas in the array, f d represents the Doppler shift caused by vehicle movement, c represents the speed of light in a vacuum, Δ represents the spacing between antenna units, R represents the radius of the ultra-large-scale circular antenna array, v represents the vehicle speed, φ(x i ,y i ) represents the phase configuration on the i-th antenna element, L(x i ,y i ) represents the distance from the mobile vehicle to the i-th antenna unit in the base station's ultra-large-scale antenna array.

[0024] Furthermore, in step 6, the base station performs a beamforming parameter adjustment scheme according to the channel model, and adjusts the beam phase configuration scheme Φ of the ultra-large-scale antenna array to maximize the channel gain from the antenna array to the mobile vehicle, thereby maximizing the data transmission rate between the two. If the projection of the vehicle is outside the antenna array, then for the i-th antenna unit, its phase configuration φ(x i ,y i )∈Φ first-order derivative φ'(x i ,y i ), obtained by the following formula:

[0025] Where B represents the system bandwidth, L(x i ,y i ) represents the distance from the i-th antenna unit to the moving vehicle, η1 represents the nonlinear module ratio, η2 is used to control the ratio of the tangent curve, L min Indicates the minimum distance between the antenna unit and the moving vehicle in the ultra-large-scale circular antenna array, L max Indicates the maximum distance between the antenna unit and the moving vehicle in the very large circular antenna array, which is as follows:

[0026] The present invention takes L min The coordinates of the antenna unit when min ,y min ), take L max The coordinates of the antenna unit when max ,y max ). In order to meet the beam focusing in the near field, the beam phase needs to be Linear change, that is, it needs to satisfy and By substituting these two equations into equation 5 and solving them, we can get the values ​​of η1 and η2. Then, by substituting η1 and η2 into equation 5 and solving the integral, we can get the phase configuration φ(x i ,y i ).

[0027] Furthermore, in step 6, the base station adjusts the beamforming parameter scheme according to the channel model, and optimizes the data transmission performance between the two by adjusting the beam phase configuration scheme Φ of the ultra-large-scale antenna array. If the projection of the vehicle is within the antenna array, then for the i-th antenna unit, its phase configuration φ(x i ,y i )∈Φ, is obtained by the following formula:

[0028] Where B is the system bandwidth, c is the speed of light in vacuum, L(x i ,y i ) represents the distance from the i-th antenna unit to the moving vehicle, L min Indicates the minimum distance between the antenna unit and the moving vehicle in the ultra-large-scale circular antenna array, L max Indicates the maximum distance between the antenna unit and the moving vehicle in a very large circular antenna array. Beneficial effects:

[0029] 1. The present invention proposes a Doppler-shift-resistant near-field beamforming method for the Internet of Vehicles (IoV). The basic idea is that when a moving vehicle in an urban environment is in the near-field area of ​​a surrounding base station, the distance from the vehicle to the center of the base station's ultra-large-scale uniform circular antenna array, the complementary angle between the vehicle and the antenna array plane, and the vehicle's speed are determined; then, the distance between the moving vehicle and each antenna unit in the base station's ultra-large-scale antenna array is determined based on the above-mentioned vehicle-related parameters; then, the IoV near-field channel model is used to determine the equivalent channel from each antenna unit in the base station's ultra-large-scale antenna array to the moving vehicle; then, the base station adjusts the beamforming parameter scheme based on the equivalent channel and applies the beam parameter adjustment scheme to the antenna array; finally, through this beam design scheme, the data transmission performance between the vehicle and the base station antenna array is maximized.

[0030] 2. The anti-Doppler shift near-field beamforming method for the Internet of Vehicles proposed in the present invention can be applied to wireless communications in high-frequency bands such as millimeter waves and terahertz, providing a novel and efficient solution for near-field wireless communication beamforming of ultra-large-scale array antennas, and providing an advanced technical method for strengthening the data transmission guarantee of the Internet of Vehicles in urban environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a system diagram of a Doppler-shift-resistant near-field wireless communication beamforming method for Internet of Vehicles according to the present invention.

[0032] FIG2 is a flow chart of a near-field wireless communication beamforming method for Internet of Vehicles with Doppler shift resistance according to the present invention.

[0033] FIG3 is a schematic diagram of a scenario in which a vehicle projection is located within an antenna array on the base station side in a near-field wireless communication beamforming method with Doppler shift resistance for Internet of Vehicles according to the present invention.

[0034] FIG4 is a schematic diagram of a scenario in which a vehicle projection is located outside the antenna array on the base station side in a near-field wireless communication beamforming method with Doppler shift resistance for the Internet of Vehicles according to the present invention. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below with reference to the accompanying drawings.

[0036] As shown in FIG1 and FIG2, a near-field wireless communication beamforming method with Doppler shift resistance for the Internet of Vehicles includes the following steps:

[0037] Step 1: In an urban environment, each base station is equipped with a large-scale uniform circular antenna array. The far-field and near-field boundaries D in the coverage area are determined based on the antenna array characteristic parameters. The number of antennas is N. t , R represents the radius of the ultra-large-scale circular antenna array at the base station, λ C represents the carrier wavelength of the communication system, assuming that the array radius is R = 0.1m, the system bandwidth is B = 40Ghz, and the carrier frequency is f c = 200 GHz, the speed of light in vacuum c = 3 × 10 8 m / s, from formula 1: The near-field boundary D in the antenna array coverage area is obtained as D = 53.3 m;

[0038] Step 2: When a vehicle in an urban environment is within the coverage area of ​​the base station, the mobile terminal updates its location information to the base station via a reverse link. The base station determines whether the mobile terminal is within the near-field area based on the location information. If so, it proceeds to the next step. If not, it repeats step 2.

[0039] Step 3: When a vehicle moving in an urban environment is within the near field of the base station, the mobile terminal updates its location information to the base station via a reverse link. The base station then determines the distance lm from the vehicle to the center of the antenna array, the complementary angle θ between the vehicle and the antenna array plane, and the vehicle's speed v along a straight line based on the vehicle's location information.

[0040] Step 4: Based on the relevant position parameters of the mobile vehicle, including the distance l and the angle θ), determine the distance L(x, y) between the mobile vehicle and each antenna element in the base station's very large-scale antenna array, where x represents the component of the antenna element on the x-axis in the plane where the very large-scale circular antenna is located, and y represents the component of the antenna element on the y-axis in the plane where the very large-scale circular antenna is located. In this embodiment, it is assumed that l = 20m and θ = 30°.

[0041] Step 5: Based on the near-field channel model of the Internet of Vehicles, determine the channel expression from each antenna unit in the base station's ultra-large-scale antenna array to the mobile vehicle;

[0042] Step 6: The base station adjusts the beamforming parameters according to the channel expression and performs beamforming control on the array antenna based on the adjusted parameters;

[0043] Step 7: Based on the periodic location update information of the mobile terminal, if yes, jump to the above step 2, if not, repeat step 7.

[0044] In step 4 of the present invention, at time t, the distance between the mobile vehicle and the antenna unit in the base station's ultra-large-scale antenna array is substituted into equation 2: In this case, we can get the following formula:

[0045] Among them, x i represents the component of the ith antenna unit on the x-axis in the plane where the ultra-large-scale circular antenna is located, and x∈[x min ,x max ], y i represents the component of the ith antenna unit on the y-axis in the plane where the ultra-large-scale circular antenna is located, and y∈[y min ,y max ], σ represents the distance added by the vehicle during the movement, and its calculation formula is as follows:

[0046] σ=vt Equation 3

[0047] Where v represents the vehicle speed and t represents the vehicle travel time.

[0048] In step 5 of the present invention, when the frequency is f and the time is t, the channel from the i-th antenna unit in the base station's ultra-large-scale antenna array to the mobile vehicle is obtained by the following formula:

[0049] Among them, x i represents the component of the i-th antenna unit on the x-axis in the plane where the ultra-large-scale circular antenna is located, y i represents the component of the ith antenna element on the y-axis in the plane where the ultra-large-scale circular antenna is located, N trepresents the number of antennas in the array, c represents the speed of light in a vacuum, Δ represents the spacing between antenna units, and λ c represents the carrier wavelength, γ represents the angle between the vehicle's driving direction and the line connecting the array center and the coordinate z-axis (the value is the same as θ in this embodiment), R represents the radius of the ultra-large-scale circular antenna array, v represents the vehicle's driving speed, φ(x i ,y i ) represents the phase configuration on the i-th antenna element, L(x i ,y i ) represents the distance from the mobile vehicle to the i-th antenna unit in the base station's ultra-large-scale antenna array.

[0050] In step 6 of the present invention, the base station adjusts the beamforming parameter scheme according to the channel model, and adjusts the beam phase configuration scheme Φ of each antenna unit in the ultra-large-scale antenna array to maximize the channel gain from the antenna array to the mobile vehicle, thereby maximizing the data transmission rate between the two. If the projection of the vehicle is outside the antenna array, then for the i-th antenna unit, its phase configuration φ(x i ,y i )∈Φ first-order derivative φ'(x i ,y i ), obtained by the following formula:

[0051] Where B represents the system bandwidth, assuming B = 40 GHz, L(x i ,y i ) represents the distance from the i-th antenna unit to the moving vehicle, η1 represents the nonlinear module ratio, η2 is used to control the ratio of the tangent curve, L min Indicates the minimum distance between the antenna unit and the moving vehicle in the ultra-large-scale circular antenna array, L max Indicates the maximum distance between the antenna unit and the moving vehicle in the ultra-large-scale circular antenna array, which is as follows:

[0052] Substituting the parameters in step 4 into equations 6 and 7, we can obtain:

[0053] The present invention takes L min The coordinates of the antenna unit when min ,y min ), take L max The coordinates of the antenna unit when max ,y max ). In order to meet the beam focusing in the near field, the beam phase needs to be Linear change, that is, it needs to satisfy and By substituting these two equations into equation 5 and solving them, we can get the values ​​of η1 and η2. Then, by substituting η1 and η2 into equation 5 and solving the integral, we can get the phase configuration φ(x i ,y i ). The phase configuration of each antenna unit is combined into the phase configuration scheme Φ of the entire antenna array.

[0054] In step 6 of the present invention, the base station adjusts the beamforming parameter scheme according to the channel model, and optimizes the data transmission performance between the two by adjusting the beam phase configuration scheme Φ of the ultra-large-scale antenna array. If the projection of the vehicle is within the antenna array, then for the i-th antenna unit, its phase configuration φ(x i ,y i )∈Φ, is obtained by the following formula:

[0055] Where B represents the system bandwidth, which is 40 GHz here, c represents the speed of light in vacuum, and L(x i ,y i ) represents the distance from the i-th antenna unit to the moving vehicle, L min and L max They represent the minimum and maximum distances between the antenna unit and the moving vehicle in the very large circular antenna array.

[0056] Figure 3 is a scenario diagram of the near-field wireless communication beamforming method for resisting Doppler shift in the Internet of Vehicles of the present invention. As shown in the figure, in this case, the projection of the moving vehicle is located within the base station side antenna array, and linear frequency modulation LFM and hybrid nonlinear frequency modulation hybrid-FM are used to generate signals when designing the near-field beam vector.

[0057] Figure 4 is a scenario diagram of the near-field wireless communication beamforming method for resisting Doppler shift in the Internet of Vehicles of the present invention. As shown in the figure, in this case, the projection of the moving vehicle is outside the antenna array on the base station side, and hybrid nonlinear frequency modulation hybrid-FM is used to generate the signal when designing the near-field beam vector.

[0058] The present invention adopts a Doppler-shift-resistant near-field wireless communication beamforming method for the Internet of Vehicles. When a moving vehicle is located in the near-field area covered by the ultra-large-scale uniform circular antenna array at the base station, it is necessary to consider the propagation characteristics of spherical waves and adjust the technical parameters of its beamforming to ensure its communication with the base station: first, the distance between the vehicle and the center of the ultra-large-scale uniform circular antenna array at the base station, the complementary angle between the vehicle and the antenna array plane, and the vehicle's speed are used to calculate the distance between the vehicle and each antenna unit in the antenna array; then, the channel expression from each antenna unit in the ultra-large-scale antenna array of the base station to the moving vehicle is determined; then, the beamforming parameter scheme of the antenna array is adjusted according to the channel expression, and the beam phase configuration scheme is applied to each antenna unit in the array; finally, the beam parameter scheme is adjusted to maximize the data transmission performance between the vehicle and the base station antenna array, and the corresponding beamforming parameter adjustment and beamforming control are performed according to the periodic mobile terminal position update information. After the implementation of this method, the anti-Doppler frequency shift data transmission performance of near-field wireless communication between vehicles and base stations can be effectively improved, providing an advanced technical method for ultra-large-scale array antenna near-field communication beamforming.

[0059] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A near - field wireless communication beamforming method for vehicle - to - everything (V2X) that resists Doppler frequency shift, characterized in that The method includes the following steps: Step 1: Configure a very large-scale uniform circular antenna array for each base station in the urban environment, and determine the boundary between the near-field and far-field regions in the coverage area according to the characteristic parameters of the antenna array; Step 2: When a moving vehicle in the urban environment is within the coverage area of the base station, the mobile terminal updates its location information to the base station through the reverse link. The base station determines whether the mobile terminal is in the near-field region according to the location information. If so, proceed to the next step; otherwise, repeat this step 2; Step 3: When a moving vehicle in the urban environment is in the near-field region of the base station, the base station determines the distance from the vehicle to the center of the antenna array, the complementary angle of the angle between the vehicle and the antenna array plane, and the speed of the vehicle moving along a straight line according to the location information of the vehicle; Step 4: Determine the distance L(x,y) between the moving vehicle and each antenna element in the very large-scale antenna array of the base station according to the location-related parameters of the moving vehicle, including the distance and angle, where x represents the component of the antenna element on the x-axis in the plane of the very large-scale circular antenna, and y represents the component of the antenna element on the y-axis in the plane of the very large-scale circular antenna; Step 5: Determine the channel expression from each antenna element in the very large-scale antenna array of the base station to the moving vehicle according to the near-field channel model of the vehicle-to-everything network; Step 6: The base station adjusts the beamforming parameters according to the channel expression and performs beamforming control on the array antenna according to the adjusted parameters; Step 7: According to the periodic location update information of the mobile terminal, if so, jump to step 2 above; otherwise, repeat this step 7.

2. A near-field wireless communication beamforming method for vehicle-to-everything (V2X) that resists Doppler frequency shift according to claim 1, wherein In the above step 5, the channel expression from each antenna element in the base station's very large-scale antenna array to the moving vehicle is as follows at time t and frequency f: Among them, N t represents the number of antennas in the array, x i represents the x-axis component of the i-th antenna element in the plane of the very large circular antenna, y i represents the y-axis component of the i-th antenna element in the plane of the very large circular antenna, N t represents the number of antennas in the array, c represents the speed of light in a vacuum, Δ represents the spacing distance between antenna elements, λ c represents the carrier wavelength, γ represents the angle between the line connecting the vehicle's traveling direction and the array center and the coordinate z-axis, R represents the radius length of the very large circular antenna array, v represents the vehicle's traveling speed, φ(x i , y i ) represents the phase configuration on the i-th antenna element, L(x i , y i ) represents the distance from the moving vehicle to the i-th antenna element in the base station's very large antenna array.

3. A near-field wireless communication beamforming method for vehicle-to-everything (V2X) that resists Doppler frequency shift according to claim 1, wherein In step 6, the beam phase configuration scheme Φ in the very large scale antenna array includes the beam phase configuration of each antenna element. If the projection of the vehicle is outside the antenna array, then for the i-th antenna element, the first derivative φ'(x i , y i ) ∈ Φ of φ(x i , y i ) is obtained through the following formula: where B represents the system bandwidth, L(x i ,y i ) represents the distance from the i-th antenna element to the moving vehicle, η1 represents the non-linear module ratio, η2 is used to control the ratio of the tangent curve, L min represents the minimum distance from the antenna element in the very large-scale circular antenna array to the vehicle, and L max represents the maximum distance from the antenna element in the very large-scale circular antenna array to the vehicle.

4. A near-field wireless communication beamforming method for anti-Doppler frequency shift in vehicle-to-everything (V2X) according to claim 3, characterized in that The first derivative φ'(x i , y i ) of the phase configuration φ(x i , y i ) of the i-th antenna element needs to satisfy that the beam phase changes linearly on , that is, it needs to satisfy the following equation: where x min and y min respectively represent the x-axis and y-axis coordinate components of the antenna element with the smallest distance from the vehicle in the very large-scale circular antenna array, x max and y max respectively represent the x-axis and y-axis coordinate components of the antenna element with the largest distance from the vehicle in the very large-scale circular antenna array. By substituting these two expressions into Equation 5, the values of η1 and η2 are obtained, and then the integral is solved to obtain the phase configuration φ(x i , y i ) of the i-th antenna element.

5. A near-field wireless communication beamforming method for vehicle-to-everything (V2X) that resists Doppler frequency shift according to claim 1, characterized in that In step 6, the beam phase configuration scheme Φ in the very large-scale antenna array includes the beam phase configuration of each antenna element. If the projection of the vehicle is within the antenna array, for the i-th antenna element, its phase configuration φ(x i ,y i ) ∈ Φ is obtained through the following formula: where B represents the system bandwidth, c represents the speed of light in vacuum, L(x i ,y i ) represents the distance from the i-th antenna element to the moving vehicle, L min represents the minimum distance from the antenna element in the very large-scale circular antenna array to the moving vehicle, L max represents the maximum distance from the antenna element in the very large-scale circular antenna array to the moving vehicle.

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