A Modeling Method for Vehicle-to-Vehicle Multi-hop Reflection Channel Based on a Double Elliptic Double Cylindrical Structure
By adopting a vehicle-to-vehicle multi-hop reflection channel modeling method with a double elliptical double cylindrical structure, the problem of insufficient description of multiple signal reflections and far-end scatterer reflection paths in existing models is solved, and accurate modeling and analysis of urban vehicle-to-vehicle communication environment is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING UNIV OF POSTS & TELECOMM
- Filing Date
- 2026-02-06
- Publication Date
- 2026-05-26
AI Technical Summary
Existing vehicle channel modeling methods based on regular geometry are insufficient in describing multiple signal reflections and the reflection paths of far-end scatterers, making it difficult to accurately characterize the wireless propagation characteristics of vehicle communication scenarios.
A double-elliptic double-cylinder structure is used to model static near-end and far-end scatterers in the vehicle communication environment. The double-cylinder structure is combined to describe moving scatterers, and a vehicle-to-vehicle multi-hop reflection channel model is constructed. The multiple reflection components of the signal are considered, and the space-time correlation function is derived to verify the accuracy of the model.
This study enriches the modeling methods for vehicle-to-vehicle channels, enabling a more accurate depiction of the wireless propagation environment of urban vehicle-to-vehicle communication. It compensates for the shortcomings of existing models and provides important reference value.
Smart Images
Figure CN122092997A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of channel modeling technology, and in particular to a method for modeling vehicle-to-vehicle multi-hop reflection channels with a double-elliptical double-cylinder structure. Background Technology
[0002] With the rapid development of intelligent transportation systems and vehicle-to-everything (V2X) technology, the demand for wireless communication between vehicles and between vehicles and roadside infrastructure continues to grow. Influenced by factors such as high-speed relative motion, multiple scatterer distribution, strong non-stationarity, and complex propagation environments, wireless channels in vehicle communication scenarios exhibit propagation characteristics significantly different from traditional cellular communication channels in the time, spatial, and frequency domains. Therefore, constructing a channel model that can accurately characterize the statistical characteristics and time-varying behavior of wireless channels in vehicle communication environments is of great significance for the design, performance evaluation, and verification of related algorithms for vehicle communication systems.
[0003] Existing vehicle channel modeling methods mainly include measurement-based channel models and regular geometry-based random channel models. Measurement-based channel models rely on a large amount of field test data. While they can reflect channel characteristics in specific scenarios to some extent, they suffer from high measurement costs, limited applicability, and insufficient model versatility. In contrast, regular geometry-based random channel models explicitly model the spatial distribution and geometric relationships of scatterers. This ensures the physical interpretability of the model while flexibly characterizing multipath propagation characteristics in different vehicle communication scenarios, thus attracting widespread attention in vehicle communication channel modeling research.
[0004] However, existing vehicle channel modeling methods based on regular geometric models still have certain shortcomings in describing scatterer distribution, path evolution, and Doppler effects. For example, existing models consider fewer signal reflections than the actual number of reflections and do not adequately characterize the reflection paths caused by far-end scatterers, making it difficult for the models to accurately describe signal propagation in real road environments. Therefore, there is an urgent need to propose a vehicle channel modeling method based on regular geometric models that can more realistically reflect the propagation characteristics of vehicle communication scenarios and has both modeling accuracy and flexibility. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a vehicle-to-vehicle multi-hop reflection channel modeling method using a double-elliptical double-cylindrical structure. This method fully considers the influence of multiple signal reflection components during the modeling process. It employs a double-elliptical structure to model the static near-end and far-end scatterers around the transmit and receive ends, and a double-cylindrical structure to describe the moving scatterers around the transmit and receive ends. This solves the problems of existing channel models based on regular geometry in characterizing the multiple signal reflection process and the reflection paths caused by far-end scatterers.
[0006] Therefore, the technical solution adopted in this invention is a vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylindrical structure, comprising the following steps:
[0007] (1) Determine the required geometric elements and simulation time in the vehicle-to-vehicle multi-hop reflection channel model with double elliptical double cylindrical structure, and establish a coordinate system.
[0008] (2) Based on the double elliptical double cylindrical structure, determine the characteristic parameters required for the channel model, including the motion speed parameters of the transmitter and receiver, antenna array parameters, carrier frequency, spatial distribution parameters of the scatterer, and motion speed parameters of the movable scatterer.
[0009] (3) Initialize the simulation start time and set the current simulation time; based on the spatial distribution relationship of the scatterers in the double elliptical double cylindrical structure, determine whether there is an obstacle blocking it, and thus construct the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system; if there is an obstacle blocking it between the transmitting end and the receiving end, the channel impulse response includes single-hop (SB), double-hop (DB) and multiple-hop (MB) reflection components; otherwise, the channel impulse response further includes line-of-sight (LoS) components.
[0010] (4) During the set simulation time, based on the relative motion relationship between the transmitter, receiver and the scatterer in the double elliptical double cylindrical structure, the time-varying angle of arrival, time-varying elevation angle of the signal, as well as the time-varying geometric position relationship between the transmitter, receiver and the scatterer, time-varying Doppler frequency shift and time-varying propagation path length are calculated and updated hourly until the simulation time ends.
[0011] (5) Calculate the space-time correlation function to analyze the channel characteristics and compare them with the measured data to verify the accuracy of the model.
[0012] Step (1): Determine the required geometric elements and simulation time in the vehicle-to-vehicle multi-hop reflection channel model with a double-elliptical double-cylinder structure, and establish a coordinate system as follows:
[0013] The model includes an inner ellipse with a semi-major axis of a1, a semi-medium axis of b1, a semi-minor axis of c1, and a focal length of D, which is used to represent the distribution range of the vehicle's static near-end scatterers.
[0014] The model also includes an outer ellipse with a semi-major axis of a2, a semi-medium axis of b2, a semi-minor axis of c2, and a focal length of D, which is used to represent the distribution range of the vehicle's static far-end scattering body.
[0015] At the common focus of the inner and outer ellipses, there are two cylinders with radii respectively. and The heights are respectively and This is used to represent the distribution range of the near-end scattering bodies of the vehicles at both the transmitting and receiving ends.
[0016] The simulation time is set to T, and a coordinate system is established with the transmitter as the origin. The initial coordinate positions of the transmitter and receiver are as follows: and .
[0017] Step (2): Based on the double-elliptical double-cylinder structure, determine the characteristic parameters required for the channel model, including the motion velocity parameters of the transmitter and receiver, antenna array parameters, carrier frequency, spatial distribution parameters of the scatterer, and motion velocity parameters of the movable scatterer, as follows:
[0018] Based on step (1), set the mobile receiver R X and mobile transmitter T X The speeds are respectively and The directions of motion are respectively and .
[0019] Both the transmitting and receiving ends are equipped with uniform linear antenna arrays, and the number of antenna elements in the transmitting antenna array and the receiving antenna array are respectively... and The antenna element spacing is as follows: and The azimuth and elevation angles of the transmitting antenna are respectively and The azimuth and elevation angles of the receiving antenna are respectively and .
[0020] Set the carrier frequency to f c N2 static near-end scatterers S2 are distributed on the inner ellipse, and N3 static far-end scatterers S3 are distributed on the outer ellipse, with a receiver R... X N4 moving near-end scatterers S4 are distributed on the surrounding cylinder, at the transmitting end T X N1 moving near-end scatterers S1 are distributed on the surrounding cylinder.
[0021] The speeds of the moving near-end scatterers are respectively and The directions of motion are respectively and .
[0022] The signal sent by the transmitter reaches the receiver through different reflection paths formed by various scatterers.
[0023] The relevant parameters are defined as shown in Table 1.
[0024] Table 1 Model Parameters and Definitions
[0025]
[0026] Step 3): Initialize the simulation start time and set the current simulation time. Based on the spatial distribution of scatterers in the double-elliptical double-cylindrical structure, determine whether there are obstacles blocking the path, and thus construct the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system. If there are obstacles blocking the path between the transmitter and receiver, the channel impulse response includes SB, DB, and MB reflection components. When there are no obstacles blocking the path between the transmitter and receiver, the channel impulse response further includes a LoS component, as follows:
[0027] Initialization Simulation Start Time ,make Then, the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system is established:
[0028]
[0029] The channel impulse response expressions for the LoS component, SB component, DB component, and MB component are as follows:
[0030]
[0031]
[0032]
[0033]
[0034] Where p = 1, 2, ..., A T , q=1,2,…,A R These represent the antenna indices at the transmitting and receiving ends, respectively, where K is the Rice factor. Indicates the transmitting antenna to the receiving antenna Link power, , and These are the normalized power coefficients of each component, satisfying... , It is the carrier wavelength. This indicates the number of scatterers in the SB component that cause the first bounce reflection. and These represent the number of scatterers in the DB component that cause the first and second bounce reflections, respectively. and These represent the number of scatterers in the MB component that cause the first and last bounce reflections, respectively. This indicates the time-varying propagation distance of the signal under the Loss of Suppression (LoS) condition. It is the time-varying Doppler frequency shift of the Loss component. Indicating the SB-th component Time-varying propagation distance of the signal reflection path Indicating the SB component The time-varying Doppler frequency shift, Indicating DB component Time-varying propagation distance of the signal reflection path Indicating DB component The time-varying Doppler frequency shift, Indicating MB components Time-varying propagation distance of the signal reflection path Indicating MB components The time-varying Doppler frequency shift.
[0035] SB component , and It is the reflection component produced by the near-end scatterer. It is the reflection component produced by the far-end scatterer, in the DB component. , and It is the reflection component produced by the near-end scatterer. , and The MB component is the reflection component generated by the far-end scatterer. The MB component takes into account the influence of all scatterers around the transmitting and receiving ends. We use the virtual path method to make an approximate model.
[0036] Step 4): Within the set simulation time, based on the relative motion relationships between the transmitter, receiver, and scatterers in the double-elliptical double-cylindrical structure, calculate and update the time-varying angle of arrival, time-varying elevation angle, time-varying geometric positional relationships between the transmitter, receiver, and scatterers, time-varying Doppler frequency shift, and time-varying propagation path length of the signal hourly, until the simulation time ends, as follows:
[0037] At the initial moment The various angles are obtained in the following way: the pitch angles corresponding to all components are generated using a cosine distribution. :
[0038]
[0039] in , express The maximum pitch angle of the reflection path formed by the scatterer.
[0040] The azimuth angles corresponding to all components are generated using the Von Mises distribution through the modified equal-area method. :
[0041]
[0042] in , express The mean azimuth angle of the reflection path formed by the scatterer. This indicates the degree to which the angles are concentrated around the mean. Denotes the zeroth-order modified Bessel function of the first kind. This represents the integral variable.
[0043] The horizontal coordinate positions of the transmitting and receiving ends at time t are represented by the following formula:
[0044]
[0045]
[0046] in It is the initial horizontal distance between the transmitting and receiving ends. and These represent the speeds of the transmitting and receiving ends, respectively. and These are the velocity azimuth angles of the transmitting and receiving ends, respectively.
[0047] The horizontal coordinates of the center of the double-loop ellipse at time t are:
[0048]
[0049] The horizontal distance between the transmitting and receiving ends at time t is expressed by the following formula:
[0050]
[0051] As the transmitting and receiving ends move, the major semi-axis of the double-loop ellipse... and Things will also change:
[0052]
[0053]
[0054] in , .
[0055] The Los component in step 3) This indicates the time-varying propagation distance of the signal under the Loss of Suppression (LoS) condition. The time-varying Doppler frequency shift of the LoS component can be expressed as:
[0056]
[0057]
[0058] in and This represents the difference between the current antenna index and the antenna center position. and This indicates the antenna spacing between the transmitting and receiving antennas. and It refers to the azimuth angles of the transmitting antenna and the receiving antenna. and It refers to the elevation angle of the transmitting antenna and the receiving antenna. It is the time-varying azimuth of arrival of the Loss component. It is the time-varying pitch angle of the Loss component. It is the time-varying departure azimuth of the Loss component. It is the time-varying pitch angle of the Los component.
[0059] The SB component in step 3) SB component Time-varying propagation distance of the signal reflection path Indicating the SB component The time-varying Doppler frequency shift, for These parameters can be expressed as follows:
[0060]
[0061]
[0062] in Indicates the center of the transmitter array to the scatterer The time-varying distance, Represents a scatterer to the center of the receiving array The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the movement, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer The time-varying azimuth and elevation angles at the receiving end.
[0063] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0064]
[0065]
[0066] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer The time-varying azimuth and elevation angles at the receiving end.
[0067] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0068]
[0069]
[0070] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer The time-varying azimuth and elevation angles at the receiving end.
[0071] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0072]
[0073]
[0074] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the movement, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer Time-varying azimuth and elevation angles at the receiving end;
[0075] The DB component in step 3) Indicating DB component Time-varying propagation distance of the signal reflection path Indicating DB component The time-varying Doppler frequency shift.
[0076] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0077]
[0078]
[0079] in .
[0080] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0081]
[0082]
[0083] in .
[0084] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0085]
[0086]
[0087] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0088]
[0089]
[0090] in .
[0091] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0092]
[0093]
[0094] in .
[0095] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0096]
[0097]
[0098] in .
[0099] The MB component in step 3) Indicating MB components The time-varying propagation distance of the signal reflection path was determined by... This represents the length of the virtual link in multi-hop reflection, where Represents the speed of light. Represents virtual latency, where This represents the delay scaling parameter. Indicates delay spread, obey Uniform distribution Indicating MB components The time-varying Doppler frequency shift.
[0100] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0101]
[0102]
[0103] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0104]
[0105]
[0106] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0107]
[0108]
[0109] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0110]
[0111]
[0112] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0113]
[0114]
[0115] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0116]
[0117]
[0118] Step 5): Calculate the space-time correlation function to analyze channel characteristics and compare it with measured data to verify the accuracy of the model.
[0119] The expression for the spacetime related function is as follows:
[0120]
[0121] in This represents the complex conjugate operation. This represents the expectation operation. Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna.
[0122] The beneficial effects of this invention include:
[0123] This invention establishes a vehicle-to-vehicle multi-hop reflection channel model with a double-elliptic double-cylinder structure. It employs a regular geometry of double ellipsoids and double cylinders to describe the distribution of scatterers in vehicle-to-vehicle communication, allowing for flexible matching of scatterer distributions in real-world scenarios. It also considers the influence of reflection paths formed by far-end scatterers and models and analyzes all components of the signal in the channel model, particularly focusing on multi-reflection components not analyzed in other regular geometric models. Furthermore, this invention derives the spatiotemporal correlation functions for different components. Combining these points, this invention enriches vehicle-to-vehicle channel modeling methods, compensates for shortcomings in past research, and accurately characterizes the wireless propagation environment of urban vehicle-to-vehicle communication, providing significant reference value for the analysis of urban vehicle-to-vehicle channel modeling research. Attached Figure Description
[0124] Figure 1 This is a flowchart illustrating the multi-hop reflection channel modeling for the vehicle-to-vehicle structure of the double-elliptical double-cylinder structure of this invention.
[0125] Figure 2 This is a schematic diagram of the basic geometric structure of a vehicle-to-vehicle multi-hop reflection channel model with a double elliptical double cylindrical structure.
[0126] Figure 3 This is a channel model that includes the reflection paths and angles of surrounding near-end scatterers.
[0127] Figure 4 This is a channel model that includes the reflection path and angle of the far-end scatterer.
[0128] Figure 5 This is the time correlation function at different speeds.
[0129] Figure 6 This represents the spatial correlation function under different scatterer concentration directions.
[0130] Figure 7 This is the time correlation function under different angle concentration parameters.
[0131] Figure 8 This is the spatial correlation function under different angular concentration parameters.
[0132] Figure 9 This is the time-dependent function for both Loss and Non-LoS scenarios.
[0133] Figure 10 This is the spatial correlation function for the Loss and NLoS cases.
[0134] Figure 11This is a comparison graph of the time correlation function between the model and the measured data.
[0135] Figure 12 This is a comparison graph of the spatial correlation function between the model and the measured data. Detailed Implementation
[0136] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0137] like Figure 1 As shown, a method for modeling a vehicle-to-vehicle multi-hop reflection channel with a double-elliptic double-cylindrical structure is presented. This method includes the following sequential steps:
[0138] Step 1): Determine the required geometric elements and simulation time in the vehicle-to-vehicle multi-hop reflection channel model with a double-elliptical double-cylinder structure, and establish a coordinate system as follows:
[0139] like Figure 2 As shown, the model includes an inner ellipse with a semi-major axis of a1, a semi-median axis of b1, a semi-minor axis of c1, and a focal length of D, which is used to represent the distribution range of the vehicle's static near-end scatterers.
[0140] The model also includes an outer ellipse with a semi-major axis of a2, a semi-medium axis of b2, a semi-minor axis of c2, and a focal length of D, which is used to represent the distribution range of the vehicle's static far-end scattering body.
[0141] At the common focus of the inner and outer ellipses, there are two cylinders with radii respectively. and The heights are respectively and This is used to represent the distribution range of the near-end scattering bodies of the vehicles at both the transmitting and receiving ends.
[0142] The simulation time is set to T, and a coordinate system is established with the transmitter as the origin. The initial coordinate positions of the transmitter and receiver are as follows: and .
[0143] Step 2): Based on the described double-elliptical double-cylinder structure, determine the characteristic parameters required for the channel model, including the motion velocity parameters of the transmitter and receiver, antenna array parameters, carrier frequency, spatial distribution parameters of the scatterer, and motion velocity parameters of the movable scatterer, as follows:
[0144] Based on step 1), set up the mobile receiver R. X and mobile transmitter T X The speeds are respectively and The directions of motion are respectively and .
[0145] Both the transmitting and receiving ends are equipped with uniform linear antenna arrays, and the number of antenna elements in the transmitting antenna array and the receiving antenna array are respectively... and The antenna element spacing is as follows: and The azimuth and elevation angles of the transmitting antenna are respectively and The azimuth and elevation angles of the receiving antenna are respectively and .
[0146] Set the carrier frequency to f c N2 static near-end scatterers S2 are distributed on the inner ellipse, and N3 static far-end scatterers S3 are distributed on the outer ellipse, with a receiver R... X N4 moving near-end scatterers S4 are distributed on the surrounding cylinder, at the transmitting end T X N1 moving near-end scatterers S1 are distributed on the surrounding cylinder.
[0147] The speeds of the moving near-end scatterers are respectively and The directions of motion are respectively and .
[0148] The signal transmitted by the transmitter reaches the receiver through different reflection paths formed by various scatterers, just as... Figure 3 and Figure 4 As shown, the reflection paths and angles formed by the surrounding near-end scatterers and far-end scatterers are represented respectively.
[0149] Step 3): Initialize the simulation start time and set the current simulation time. Based on the spatial distribution of scatterers in the double-elliptical double-cylindrical structure, determine whether there are obstacles blocking the path, and thus construct the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system. If there are obstacles blocking the path between the transmitter and receiver, the channel impulse response includes SB, DB, and MB reflection components. When there are no obstacles blocking the path between the transmitter and receiver, the channel impulse response further includes a LoS component, as follows:
[0150] Initialization Simulation Start Time ,make Then, the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system is established:
[0151]
[0152] The channel impulse response expressions for the LoS component, SB component, DB component, and MB component are as follows:
[0153]
[0154]
[0155]
[0156]
[0157] Where p = 1, 2, ..., A T , q=1,2,…,A R These represent the antenna indices at the transmitting and receiving ends, respectively, where K is the Rice factor. Indicates the transmitting antenna to the receiving antenna Link power, , and These are the normalized power coefficients of each component, satisfying... , It is the carrier wavelength. This indicates the number of scatterers in the SB component that cause the first bounce reflection. and These represent the number of scatterers in the DB component that cause the first and second bounce reflections, respectively. and These represent the number of scatterers in the MB component that cause the first and last bounce reflections, respectively. This indicates the time-varying propagation distance of the signal under the Loss of Suppression (LoS) condition. It is the time-varying Doppler frequency shift of the Loss component. Indicating the SB-th component Time-varying propagation distance of the signal reflection path Indicating the SB component The time-varying Doppler frequency shift, Indicating DB component Time-varying propagation distance of the signal reflection path Indicating DB component The time-varying Doppler frequency shift, Indicating MB components Time-varying propagation distance of the signal reflection path Indicating MB components The time-varying Doppler frequency shift.
[0158] SB component , and It is the reflection component produced by the near-end scatterer. It is the reflection component produced by the far-end scatterer, in the DB component. , and It is the reflection component produced by the near-end scatterer. , and The MB component is the reflection component generated by the far-end scatterer. The MB component takes into account the influence of all scatterers around the transmitting and receiving ends. We use the virtual path method to make an approximate model.
[0159] Step 4): Within the set simulation time, based on the relative motion relationships between the transmitter, receiver, and scatterers in the double-elliptical double-cylindrical structure, calculate and update the time-varying angle of arrival, time-varying elevation angle, time-varying geometric positional relationships between the transmitter, receiver, and scatterers, time-varying Doppler frequency shift, and time-varying propagation path length of the signal hourly, until the simulation time ends, as follows:
[0160] At the initial moment The various angles are obtained in the following way: the pitch angles corresponding to all components are generated using a cosine distribution. :
[0161]
[0162] in , express The maximum pitch angle of the reflection path formed by the scatterer.
[0163] The azimuth angles corresponding to all components are generated using the Von Mises distribution through the modified equal-area method. :
[0164]
[0165] in , express The mean azimuth angle of the reflection path formed by the scatterer. This indicates the degree to which the angles are concentrated around the mean. Denotes the zeroth-order modified Bessel function of the first kind. This represents the integral variable.
[0166] The elevation and azimuth angles of the receiving end and the elevation and azimuth angles of the transmitting end have a transformation relationship, as follows:
[0167]
[0168]
[0169]
[0170]
[0171]
[0172]
[0173]
[0174]
[0175] Once the angle of the transmitter is generated, the angle of the receiver can be obtained through the formula.
[0176] The horizontal coordinate positions of the transmitting and receiving ends at time t are represented by the following formula:
[0177]
[0178]
[0179] in It is the initial horizontal distance between the transmitting and receiving ends. and These represent the speeds of the transmitting and receiving ends, respectively. and These are the velocity azimuth angles of the transmitting and receiving ends, respectively.
[0180] The horizontal coordinates of the center of the double-loop ellipse at time t are:
[0181]
[0182] The horizontal distance between the transmitting and receiving ends at time t is expressed by the following formula:
[0183]
[0184] The relative speed and direction of the velocity between the transmitting and receiving ends are expressed by the following formula:
[0185]
[0186]
[0187] As the transmitting and receiving ends move, the major semi-axis of the double-loop ellipse... and Things will also change:
[0188]
[0189]
[0190] in , .
[0191] The Los component in step 3) This indicates the time-varying propagation distance of the signal under the Loss of Suppression (LoS) condition. The time-varying Doppler frequency shift of the LoS component can be expressed as:
[0192]
[0193]
[0194] in and This represents the difference between the current antenna index and the antenna center position. and This indicates the antenna spacing between the transmitting and receiving antennas. and It refers to the azimuth angles of the transmitting antenna and the receiving antenna. and It refers to the elevation angle of the transmitting antenna and the receiving antenna. It is the time-varying azimuth of arrival of the Loss component. It is the time-varying pitch angle of the Loss component. It is the time-varying departure azimuth of the Loss component. The time-varying pitch angle of the LoS component can be obtained using the following formulas:
[0195]
[0196]
[0197]
[0198] The SB component in step 3) SB component Time-varying propagation distance of the signal reflection path Indicating the SB component The time-varying Doppler frequency shift.
[0199] for These parameters can be expressed as follows:
[0200]
[0201]
[0202] in Indicates the center of the transmitter array to the scatterer The time-varying distance, Represents a scatterer to the center of the receiving array The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the motion.
[0203] and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer The time-varying azimuth and elevation angles at the receiving end can be obtained using the following formulas:
[0204]
[0205]
[0206]
[0207]
[0208] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0209]
[0210]
[0211] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance.
[0212] in It is a scatterer The time-varying azimuth angle at the receiving end can be obtained using the following formula:
[0213]
[0214] in and Represents a scatterer The horizontal position coordinates at time t can be obtained using the following formula:
[0215]
[0216] in scatterer The elliptic parameter angles of the inner circle ellipse can be obtained using the following formula:
[0217]
[0218] Among them, scattering body At the initial moment Horizontal position coordinates and It can be obtained through the following formula:
[0219]
[0220] It is a scatterer Time-varying pitch angle at the receiving end, and From the emitter to the scatterer The time-varying azimuth and elevation angles can be obtained using the following formulas:
[0221]
[0222]
[0223]
[0224] in .
[0225] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0226]
[0227]
[0228] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance.
[0229] in It is a scatterer The time-varying azimuth angle at the receiving end can be obtained using the following formula:
[0230]
[0231] in and Represents a scatterer The horizontal position coordinates at time t can be obtained using the following formula:
[0232]
[0233] in scatterer The elliptic parameter angles of the inner circle ellipse can be obtained using the following formula:
[0234]
[0235] Among them, scattering body At the initial moment Horizontal position coordinates and It can be obtained through the following formula:
[0236]
[0237] It is a scatterer Time-varying pitch angle at the receiving end, and From the emitter to the scatterer The time-varying pitch angle can be obtained using the following formulas:
[0238]
[0239]
[0240]
[0241] in .
[0242] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0243]
[0244]
[0245] in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the motion.
[0246] and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer The time-varying azimuth and elevation angles at the receiving end can be obtained using the following formulas:
[0247]
[0248]
[0249]
[0250]
[0251] The DB component in step 3) Indicating DB component Time-varying propagation distance of the signal reflection path Indicating DB component The time-varying Doppler frequency shift.
[0252] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0253]
[0254]
[0255] in .
[0256] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0257]
[0258]
[0259] in .
[0260] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0261]
[0262]
[0263] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0264]
[0265]
[0266] in .
[0267] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0268]
[0269]
[0270] in .
[0271] right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows:
[0272]
[0273]
[0274] in .
[0275] The MB component in step 3) Indicating MB components The time-varying propagation distance of the signal reflection path was determined by... This represents the length of the virtual link in multi-hop reflection, where Represents the speed of light. Represents virtual latency, where This represents the delay scaling parameter. Indicates delay spread, obey Uniform distribution Indicating MB components The time-varying Doppler frequency shift.
[0276] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0277]
[0278]
[0279] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0280]
[0281]
[0282] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0283]
[0284]
[0285] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0286]
[0287]
[0288] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0289]
[0290]
[0291] for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
[0292]
[0293]
[0294] Step 5): Calculate the space-time correlation function to analyze channel characteristics and compare it with measured data to verify the accuracy of the model.
[0295] For the Loss scenario, the space-time related function expression is as follows:
[0296]
[0297] in This represents the complex conjugate operation. This represents the expectation operation. Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna , , and These represent the space-time correlation functions for the LoS component, SB component, DB component, and MB component, respectively.
[0298] If there are obstacles obstructing the view, and it is an NLoS scene, then the space-time related function expression is as follows:
[0299]
[0300] By analyzing the statistical characteristics of the channel through correlation analysis, specifically: Figure 5 As shown, as the speeds at both the transmitting and receiving ends increase, the channel changes become more drastic, and the time correlation decreases, demonstrating the impact of speed on channel time correlation; Figure 6 As shown, when the concentration direction of the scatterer deviates further and further from the line-of-sight propagation direction, the influence of the scatterer on the propagation path decreases, and the spatial correlation gradually increases, indicating the influence of the scatterer concentration direction on the channel spatial correlation; as Figure 7 and Figure 8 As shown, when the angular concentration is affected As the value increases, the obtained perspectives become more concentrated, and the temporal and spatial correlations gradually increase, indicating that... The impact of values on channel temporal and spatial correlation; such as Figure 9 and Figure 10 As shown, in the LoS scenario, the temporal and spatial correlations are significantly greater than in the NLoS scenario. This is because there are no scatterers in the LoS scenario to obstruct the propagation of the LoS component, demonstrating the impact of the LoS component on the channel's temporal and spatial correlations. Figure 11 and Figure 12 As shown, the analytical results obtained by the model are basically consistent with the experimental results, and the normalized root mean square error is within 7%, which indicates the accuracy of the proposed model.
[0301] The above description describes specific embodiments of the present invention and the technical principles employed. Any changes made in accordance with the concept of the present invention that do not exceed the spirit of the specification and drawings should still fall within the protection scope of the present invention.
Claims
1. A method for modeling vehicle-to-vehicle multi-hop reflection channels based on a double-elliptic double-cylindrical structure, characterized in that, Includes the following steps: (1) Determine the required geometric elements and simulation time in the vehicle-to-vehicle multi-hop reflection channel model with a double elliptical double cylindrical structure, and establish a coordinate system; (2) Based on the double elliptical double cylindrical structure, determine the characteristic parameters required for the channel model, including the motion velocity parameters of the transmitter and receiver, antenna array parameters, carrier frequency, spatial distribution parameters of the scatterer, and motion velocity parameters of the movable scatterer; (3) Initialize the simulation start time and set the current simulation time; based on the spatial distribution relationship of the scatterers in the double elliptical double cylindrical structure, determine whether there is an obstacle blocking it, and thus construct the channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the corresponding multi-antenna vehicle-to-vehicle system; if there is an obstacle blocking it between the transmitting end and the receiving end, the channel impulse response includes single-hop (SB), double-hop (DB) and multiple-hop (MB) reflection components; otherwise, the channel impulse response further includes line-of-sight (LoS) components; (4) During the set simulation time, based on the relative motion relationship between the transmitter, receiver and the scatterer in the double elliptical double cylindrical structure, calculate and update the time-varying angle of arrival, time-varying elevation angle of the signal, as well as the time-varying geometric position relationship between the transmitter, receiver and the scatterer, time-varying Doppler frequency shift and time-varying propagation path length, until the simulation time ends. (5) Calculate the space-time correlation function to analyze the channel characteristics and compare them with the measured data to verify the accuracy of the model.
2. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylinder structure according to claim 1, characterized in that: The vehicle-to-vehicle multi-hop reflection channel model with a double ellipse and double cylinder structure described in step (1) includes an inner ellipse with a semi-major axis of a1, a semi-median axis of b1, a semi-minor axis of c1, and a focal length of D, which is used to represent the distribution range of the vehicle's static near-end scatterer. The model also includes an outer ellipse with a semi-major axis of a2, a semi-median axis of b2, a semi-minor axis of c2, and a focal length of D, which is used to represent the distribution range of the vehicle's static far-end scattering body. At the common focus of the inner and outer ellipses, there are two cylinders with radii respectively. and The heights are respectively and , used to represent the distribution range of near-end scatterers of the vehicles at both the transmitting and receiving ends; The simulation time is set to T, and a coordinate system is established with the transmitter as the origin. The initial coordinate positions of the transmitter and receiver are as follows: and .
3. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylinder structure according to claim 1, characterized in that: The characteristic parameters required to determine the channel model in step (2) include: Set up the mobile receiver R X and mobile transmitter T X The speeds are respectively and The directions of motion are respectively and ; Both the transmitting and receiving ends are equipped with uniform linear antenna arrays. The number of antenna elements in the transmitting antenna array and the receiving antenna array are respectively... and The antenna element spacing is as follows: and The azimuth and elevation angles of the transmitting antenna are respectively and The azimuth and elevation angles of the receiving antenna are respectively and ; Set the carrier frequency to f c N2 static near-end scatterers S2 are distributed on the inner ellipse, and N3 static far-end scatterers S3 are distributed on the outer ellipse, with a receiver R... X N4 moving near-end scatterers S4 are distributed on the surrounding cylinder, at the transmitting end T X N1 moving near-end scatterers S1 are distributed on the surrounding cylinder; The speeds of the moving near-end scatterers are respectively and The directions of motion are respectively and ; The signal sent by the transmitter reaches the receiver through different reflection paths formed by various scatterers.
4. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylindrical structure according to claim 1, characterized in that: The channel impulse response from the p-th transmitting antenna to the q-th receiving antenna in the multi-antenna vehicle-to-vehicle system described in step (3) is as follows: The channel impulse response expressions for the LoS component, SB component, DB component, and MB component are as follows: Where p = 1, 2, ..., A T , q=1,2,…,A R These represent the antenna indices at the transmitting and receiving ends, respectively, where K is the Rice factor. Indicates the transmitting antenna to the receiving antenna Link power, , and These are the normalized power coefficients of each component, satisfying... , It is the carrier wavelength. This indicates the number of scatterers in the SB component that cause the first bounce reflection. and These represent the number of scatterers in the DB component that cause the first and second bounce reflections, respectively. and These represent the number of scatterers in the MB component that cause the first and last bounce reflections, respectively. This indicates the time-varying propagation distance of the signal under the Loss of Suppression (LoS) condition. It is the time-varying Doppler frequency shift of the Loss component. Indicating the SB-th component Time-varying propagation distance of the signal reflection path Indicating the SB component The time-varying Doppler frequency shift, Indicating DB component Time-varying propagation distance of the signal reflection path Indicating DB component The time-varying Doppler frequency shift, Indicating MB components Time-varying propagation distance of the signal reflection path Indicating MB components The time-varying Doppler frequency shift.
5. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylinder structure according to claim 4, characterized in that: The SB component , and It is the reflected component produced by the near-end scatterer. It is the reflection component produced by the far-end scatterer, in the DB component. , and It is the reflected component produced by the near-end scatterer. , and The MB component is the reflection component generated by the far-end scatterer. The MB component takes into account the influence of all scatterers around the transmitting and receiving ends.
6. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylindrical structure according to claim 4 or 5, characterized in that: The and They are represented as follows: in and This represents the difference between the current antenna index and the antenna center position. and This indicates the antenna spacing between the transmitting and receiving antennas. and It refers to the azimuth angles of the transmitting antenna and the receiving antenna. and It refers to the elevation angle of the transmitting antenna and the receiving antenna. It is the time-varying azimuth of arrival of the Loss component. It is the time-varying pitch angle of the Loss component. It is the time-varying departure azimuth of the Loss component. It is the time-varying pitch angle of the Los component; for The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in Indicates the center of the transmitter array to the scatterer The time-varying distance, Represents a scatterer to the center of the receiving array The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the movement, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer Time-varying azimuth and elevation angles at the receiving end; for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer Time-varying azimuth and elevation angles at the receiving end; for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer Time-varying azimuth and elevation angles at the receiving end; for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: in Represents a scatterer to the center of the receiving array The time-varying distance, Indicates the center of the transmitter array to the scatterer The time-varying distance, It is a scatterer The magnitude of the speed of movement, It is a scatterer The azimuth angle of the movement, and From the emitter to the scatterer The time-varying azimuth and elevation angles, and It is a scatterer Time-varying azimuth and elevation angles at the receiving end; right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in right The time-varying Doppler frequency shift and time-varying propagation distance are expressed as follows: in for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows: for The time-varying Doppler frequency shift and time-varying propagation distance can be expressed as follows:
7. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylinder structure according to claim 1, characterized in that: In step (4), at the initial time The various angles are obtained in the following way: the pitch angles corresponding to all components are generated using a cosine distribution. : in , express The maximum pitch angle of the reflection path formed by the scatterer; The azimuth angles corresponding to all components are generated using the Von Mises distribution through the modified equal-area method. : in , express The mean azimuth angle of the reflection path formed by the scatterer. This indicates the degree to which the angles are concentrated around the mean. Denotes the zeroth-order modified Bessel function of the first kind. Represents the integral variable; The horizontal coordinate positions of the transmitting and receiving ends at time t are represented by the following formula: in It is the initial horizontal distance between the transmitting and receiving ends. and These represent the speeds of the transmitting and receiving ends, respectively. and These are the velocity azimuth angles of the transmitting and receiving ends, respectively. The horizontal coordinates of the center of the double-loop ellipse at time t are: The horizontal distance between the transmitting and receiving ends at time t is expressed by the following formula: As the transmitting and receiving ends move, the major semi-axis of the double-loop ellipse... and Things will also change: in , .
8. The vehicle-to-vehicle multi-hop reflection channel modeling method based on a double-elliptic double-cylinder structure according to claim 1, characterized in that: In step (5), the expression for the space-time correlation function is as follows: in This represents the complex conjugate operation. This represents the expectation operation. Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna Indicates the first The transmitting antenna to the first Channel impulse response of each receiving antenna.