A two-dimensional modeling method and device for vehicle-to-vehicle broadband communication channels

Abstract

The application discloses a two-dimensional modeling method of a vehicle-to-vehicle broadband communication channel. The method comprises the following steps: based on a two-dimensional elliptical channel model and current speeds of a transmitting vehicle and a receiving vehicle in measured channel parameters at each moment, Doppler power spectrum characteristic parameters at each moment are calculated; based on time delay energy characteristic parameters at each moment in the measured channel parameters at each moment and the Doppler power spectrum characteristic parameters at each moment, channel scattering functions at each moment are calculated to correct the two-dimensional elliptical channel model corresponding to the channel scattering functions. The application only relates to vehicle-to-vehicle motion states in a two-dimensional plane, can significantly simplify a modeling process, and based on the measured channel parameters at each moment, the channel scattering functions at each moment are used to correct the corresponding two-dimensional elliptical channel model, so that the modeling accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and specifically to a two-dimensional modeling method and apparatus for vehicle-to-vehicle broadband communication channels. Background Technology

[0002] Vehicle-to-vehicle (V2V) communication, as a 5G application scenario, has significant application value in areas such as autonomous driving, rapid early warning, emergency braking, and infotainment. Channel models are fundamental to the design of V2V wireless communication systems, effectively simulating the propagation characteristics of electromagnetic waves in wireless communication environments. Current communication channel modeling methods, due to their involvement of vehicle motion states in multi-dimensional planes and the need to consider specific reflection path distributions, result in a complex modeling process and lack of correlation with measured channel data, ultimately affecting the accuracy of modeling and analysis. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the modeling process of vehicle-to-vehicle broadband communication channels in the prior art is relatively complex and is not associated with the measured channel data, which affects the accuracy of modeling and analysis, thereby providing a two-dimensional modeling method and device for vehicle-to-vehicle broadband communication channels.

[0004] According to a first aspect, embodiments of the present invention provide a two-dimensional modeling method for vehicle-to-vehicle broadband communication channels, comprising the following steps:

[0005] During the movement of the transmitting vehicle and / or the receiving vehicle, a two-dimensional elliptical channel model is created in real time with the current position of the transmitting vehicle and the receiving vehicle as the focus. In the two-dimensional elliptical channel model at each moment, the signal sent by the transmitting vehicle to the receiving vehicle is reflected by a preset scatterer to form the channel transmission path at each moment.

[0006] Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the Doppler power spectrum characteristic parameters at each time point are calculated.

[0007] Based on the measured channel parameters and Doppler power spectrum characteristics at each time point, the channel scattering function at each time point is calculated to correct the corresponding two-dimensional elliptical channel model.

[0008] In one embodiment of the first aspect, calculating the Doppler power spectrum characteristic parameters at each time step based on the two-dimensional elliptical channel model at each time step and the measured channel parameters at each time step includes:

[0009] Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the Doppler frequency shift parameters at each time point are calculated.

[0010] Based on the two-dimensional elliptical channel model at each time point, the probability density parameters of the preset scatterer in the channel delay path at each time point are calculated.

[0011] Based on the Doppler frequency shift parameters at each time point and the probability density parameters of the preset scatterer in the channel delay path at each time point, the Doppler power spectrum characteristic parameters at each time point are calculated.

[0012] In another embodiment of the first aspect, based on the two-dimensional elliptical channel model at each time moment, the calculation of the Doppler frequency shift parameter at each time moment, based on the two-dimensional elliptical channel model at each time moment and the measured channel parameters at each time moment, includes:

[0013] Based on the two-dimensional elliptical channel model at the initial moment and the measured channel parameters at each moment, the Doppler frequency shift parameters at the initial moment are calculated.

[0014] Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the current position of the preset scatterer in the channel delay path at each time point is calculated;

[0015] Based on the Doppler frequency shift parameters at the initial time and the current position of the preset scatterer in the channel delay path at each time, the Doppler frequency shift parameters at each time are calculated.

[0016] In another embodiment of the first aspect, calculating the Doppler frequency shift parameter at the initial time based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time includes:

[0017] Based on the two-dimensional elliptical channel model at the initial moment and the measured channel parameters at each moment, calculate the current position of the preset scatterer in the channel delay path at the initial moment;

[0018] Based on the current position of the preset scatterer in the channel delay path at the initial moment and the measured channel parameters at each moment, the Doppler frequency shift parameter at the initial moment is calculated.

[0019] In another embodiment of the first aspect, the calculation of the channel scattering function at each time moment to correct the corresponding two-dimensional elliptical channel model is performed by the following formula:

[0020]

[0021]

[0022] Where S(τ, f) d () represents the channel scattering function at each time point. Let p(f) be the time-delay domain energy characteristic parameter at each time step.d |τ i ) represents the Doppler power spectrum characteristic parameters at each time point, where f d Let τ be the Doppler frequency shift parameter at each time step, and τ be the time delay parameter in the channel delay path at each time step. i Let τ be the time delay parameter in the channel delay path at time i, and P(τ) be the corrected Doppler power spectrum characteristic parameter at each time.

[0023] In another embodiment of the first aspect, calculating the current positions of the transmitting vehicle and the receiving vehicle includes:

[0024] The initial position and current speed of the transmitting vehicle and the receiving vehicle are acquired in real time.

[0025] The current positions of the transmitting vehicle and the receiving vehicle are calculated based on their initial positions and current speeds.

[0026] According to the second aspect, this embodiment also provides a two-dimensional modeling device for vehicle-to-vehicle broadband communication channels, comprising the following modules:

[0027] The channel model creation module is used to create a two-dimensional elliptical channel model at each moment in real time, with the current position of the transmitting vehicle and / or the receiving vehicle as the focus, during the movement of the transmitting vehicle and / or the receiving vehicle. In the two-dimensional elliptical channel model at each moment, the signals sent by the transmitting vehicle to the receiving vehicle are reflected by a preset scatterer to form the channel transmission path at each moment.

[0028] The Doppler power spectrum calculation module is used to calculate the Doppler power spectrum characteristic parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time.

[0029] The channel scattering function correction module is used to calculate the channel scattering function at each time point based on the measured channel parameters and the Doppler power spectrum characteristic parameters at each time point, so as to correct the corresponding two-dimensional elliptical channel model.

[0030] In one embodiment of the second aspect, the Doppler power spectrum calculation module includes:

[0031] The Doppler frequency shift calculation submodule is used to calculate the Doppler frequency shift parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time.

[0032] The probability density calculation submodule is used to calculate the probability density parameters of the preset scatterer in the channel delay path at each time based on the two-dimensional elliptical channel model at each time.

[0033] The Doppler power spectrum calculation submodule is used to calculate the Doppler power spectrum characteristic parameters at each time based on the Doppler frequency shift parameters at each time and the probability density parameters of the preset scatterer in the channel delay path at each time.

[0034] According to a third aspect, embodiments of the present invention provide a computer-readable storage medium storing computer instructions for causing the computer to execute the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels as described in the first aspect or any embodiment of the first aspect.

[0035] According to a fourth aspect, this embodiment provides a computer device, including: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels as described in the first aspect or any embodiment of the first aspect.

[0036] The technical solution of this invention has the following advantages:

[0037] This invention discloses a two-dimensional modeling method and apparatus for vehicle-to-vehicle broadband communication channels. The method involves: during the movement of the transmitting vehicle and / or the receiving vehicle, creating a two-dimensional elliptical channel model at each moment, with the current position of the transmitting and receiving vehicles as the focus; in each moment's two-dimensional elliptical channel model, the signal transmitted from the transmitting vehicle to the receiving vehicle is reflected by a preset scatterer to form the channel transmission path at each moment; based on the two-dimensional elliptical channel model at each moment and the measured channel parameters at each moment, calculating the Doppler power spectrum characteristic parameters at each moment; and based on the measured channel parameters and the Doppler power spectrum characteristic parameters at each moment, calculating the channel scattering function at each moment to correct the corresponding two-dimensional elliptical channel model. This invention only relates to the vehicle motion state in a two-dimensional plane, significantly simplifying the modeling process. Furthermore, by obtaining the channel scattering function at each moment based on the measured channel parameters and correcting the corresponding two-dimensional elliptical channel model, the accuracy of the modeling is improved. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1A flowchart illustrating a specific example of a two-dimensional modeling method for a vehicle-to-vehicle broadband communication channel in an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the two-dimensional elliptical channel model at the initial moment in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the two-dimensional elliptical channel model at various times in the embodiments of the present invention;

[0042] Figure 4 A flowchart illustrating another specific example of the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels in this invention;

[0043] Figure 5 A flowchart illustrating another specific example of the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels in this invention;

[0044] Figure 6 A flowchart illustrating another specific example of the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels in this invention;

[0045] Figure 7 This is a schematic diagram of the time delay domain energy characteristic parameters at each moment in the channel measured parameters at each moment in the embodiments of the present invention;

[0046] Figure 8 This is a simulation diagram of the time-domain channel Doppler power spectrum in an embodiment of the present invention;

[0047] Figure 9 This is a schematic diagram of the modified simulated time-domain channel Doppler power spectrum in an embodiment of the present invention;

[0048] Figure 10 This is a structural block diagram of a two-dimensional modeling device for a vehicle-to-vehicle broadband communication channel in an embodiment of the present invention;

[0049] Figure 11 This is a schematic diagram of the hardware structure of a computer device in an embodiment of the present invention. Detailed Implementation

[0050] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0054] This embodiment provides a two-dimensional modeling method for vehicle-to-vehicle broadband communication channels, such as... Figure 1 As shown, it includes the following steps:

[0055] Step S11: During the movement of the transmitting vehicle and / or the receiving vehicle, a two-dimensional elliptical channel model is created in real time with the current position of the transmitting vehicle and the receiving vehicle as the focus; in the two-dimensional elliptical channel model at each moment, the signal sent from the transmitting vehicle to the receiving vehicle is reflected by a preset scatterer to form the channel transmission path at each moment.

[0056] like Figure 2 The figure shows a two-dimensional elliptical channel model corresponding to the channel delay path at the initial moment. In the vehicle-to-everything (V2V) environment, the multipath component of V2V communication originates from surrounding scatterers. These scatterers are distributed around both the transmitting vehicle Tx and the receiving vehicle Rx, causing multipath interference in the signal received by the receiving vehicle Rx. Figure 2In this scenario, assuming a scatterer exists around the road (as mentioned above), the signal received by the receiving vehicle Rx will have multiple reflected paths from the scatterer in addition to the main path. To quantize these multipath signals, a two-dimensional elliptic channel model is introduced in this embodiment. Since the time delay is the same at all points on the ellipse with the transmitting and receiving vehicles as foci (i.e., the paths are the same), this embodiment uses elliptic theory to model the V2V wireless channel.

[0057] like Figure 3 As shown, during the movement of the transmitting vehicle and / or the receiving vehicle, a two-dimensional elliptical channel model is created at each moment. That is, each channel delay path at different moments corresponds to a two-dimensional elliptical channel model. Each channel delay path is assumed to have a reflector (i.e., the preset scatterer mentioned above). Multiple channel delay paths will have multiple preset scatterers.

[0058] In one specific implementation, calculating the current positions of the transmitting vehicle and the receiving vehicle includes:

[0059] Step 1: Obtain the initial position and current speed of the transmitting and receiving vehicles in real time.

[0060] exist Figure 2 In this embodiment, based on the two-dimensional elliptical channel model at each time point, the coordinate system selected is the Cartesian coordinate system, which can be represented as x(t) = [x(t), y(t)]. C .

[0061] Step 2: Calculate the current position of the transmitting and receiving vehicles based on their initial positions and current speeds.

[0062] For example, using the two vehicles, the transmitting vehicle and the receiving vehicle, as endpoints, can be represented as follows:

[0063] x t (t)=x t0 +v t t (1);

[0064] x r (t)=x r0 +v r t (2);

[0065] Where, x t0 =[-d / 2,0] C Indicates the initial position of the launching vehicle, x r0 =[d / 2,0] C This represents the initial position of the receiving vehicle. The origin of this coordinate system is located at the midpoint of the line connecting the two vehicles, and the Y-axis is perpendicular to the line connecting the two vehicles. The velocity vector of the transmitting vehicle is... The velocity vector of the receiving vehicle is x t (t) represents the current position of the transmitting vehicle, x r (t) represents the current location of the receiving vehicle.

[0066] Step S12: Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, calculate the Doppler power spectrum characteristic parameters at each time point.

[0067] In one specific implementation, such as Figure 4 As shown, step S12 above calculates the Doppler power spectrum characteristic parameters at each time point based on the two-dimensional elliptical channel model and the measured channel parameters at each time point, including:

[0068] Step S41: Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, calculate the Doppler frequency shift parameters at each time point.

[0069] The measured channel parameters at each moment are obtained by measuring the current speeds of the transmitting and receiving vehicles in real time within the two-dimensional elliptical channel model at each moment, and then calculating x using the formulas (1) and (2) above. t (t), x r (t), based on the two-dimensional elliptic channel model at each time point, substituting x t (t), x r (t) Calculate the Doppler frequency shift parameters at each time point.

[0070] For example, the Doppler frequency shift parameters at each time point are calculated using the following formula:

[0071]

[0072] in, Let be the Doppler frequency shift parameter at time t. The current position of the preset scatterer in the channel delay path at time t. Let x be the X-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. Let x be the Y-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. t (t) represents the X-axis parameter at time t in the Cartesian coordinate system, and y t (t) represents the Y-axis parameter at time t in the Cartesian coordinate system, f c denoted as the channel center frequency, and c as the speed of light.

[0073] Step S42: Based on the two-dimensional elliptical channel model at each time point, calculate the probability density parameters of the preset scatterers in the channel delay path at each time point.

[0074] exist Figure 3 In this model, assuming the scatterer's distribution in the two-dimensional elliptical channel model space, it can be determined using probability density parameters. Given that both the transmitting and receiving vehicles have ideally isotropic omnidirectional antennas, the time-delay Doppler power spectrum p(t; f) at time t can be derived. d |τ). In order to calculate The assumption is that they are uniformly distributed in space, which is a widely used assumption.

[0075] For example, the distribution of the preset scatterers in the channel delay path at each time point in the two-dimensional elliptical channel model at each time point can be obtained in the following way:

[0076] a τ Let b be the semi-major axis of the ellipse. τ Let be the semi-minor axis of the ellipse. Then the differential arc length of the ellipse can be described as dl, which can be calculated using the following formula:

[0077]

[0078] For the eccentricity of the ellipse, It is the differential of the near-point angle. Since we assume the scatterer is uniformly distributed, the arc length is equivalent to the Doppler power spectrum. Therefore, the Doppler power spectrum p(l|τ) is uniform, for example... L τ This is the circumference of the ellipse, which can be calculated using the following formula:

[0079]

[0080] The integral expression here is called the second kind of complete elliptic integral. Once p(l|τ) is known, The calculation of the distribution requires a probability density transformation, which is calculated using the following formula:

[0081]

[0082] Through derivation, we can obtain...

[0083]

[0084] It can be known Only related to the eccentricity ε of the ellipse τ The eccentricity of the ellipse is a function of the time delay τ.

[0085] Step S43: Calculate the Doppler power spectrum characteristic parameters at each time based on the Doppler frequency shift parameters at each time and the probability density parameters of the preset scatterers in the channel delay path at each time.

[0086] For example, in the process of calculating the Doppler power spectrum, firstly, the transformation function F: It is a many-to-one conversion, multiple The same Doppler frequency shift can be obtained, Converted to Doppler power spectrum p(f d |τ), for The corresponding near-point angle, This is the Doppler frequency shift.

[0087] For example, the Doppler power spectrum characteristic parameters at each time point are calculated using the following formula:

[0088]

[0089] τ i Let p(f) be the delay parameter in the channel delay path at time i. d |τ i F represents the Doppler power spectrum characteristic parameters at each time point. -1 yes The inverse mapping, and the set F -1 (f d F is finite and countable. Although F -1 Even though it's not a closed-form problem, it can still be calculated numerically. For the Doppler frequency shift under each channel delay path... First calculate The condition is satisfied in [0, 2π). The solution, generally speaking The number of solutions can be because Different because of their differences.

[0090] In one specific implementation, such as Figure 5 As shown, step S41 above, based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, calculates the Doppler frequency shift parameters at each time point, including:

[0091] Step S51: Based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time, calculate the Doppler frequency shift parameters at the initial time.

[0092] The measured channel parameters at each moment are obtained by measuring the current speeds of the transmitting and receiving vehicles in real time within the two-dimensional elliptical channel model at each moment, and then calculating x using the formulas (1) and (2) above. t (t), x r (t), based on the two-dimensional elliptic channel model at each time point, substituting x t (t), x r (t) Calculate the Doppler frequency shift parameters at the initial time.

[0093] For example, the Doppler frequency shift parameter at the initial moment is calculated using the following formula:

[0094]

[0095] d r =-d t =d / 2, this expression depends on only one parameter. This parameter can determine the position on a two-dimensional elliptic channel model with a specific time delay. All points on a two-dimensional elliptic channel model have the same time delay.

[0096] Step S52: Based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time, calculate the current position of the preset scatterer in the channel delay path at each time.

[0097] The measured channel parameters at each moment are obtained by measuring the current speeds of the transmitting and receiving vehicles in real time within the two-dimensional elliptical channel model at each moment, and then calculating x using the formulas (1) and (2) above. t (t), x r (t), based on the two-dimensional elliptic channel model at each time point, substituting x t (t), x r (t) Calculate the current position of the preset scatterer in the channel delay path at each time step.

[0098] For example, for other times t, the movement of the transmitting and receiving vehicles will cause the ellipse to rotate. Therefore, the ellipse must rotate about the direction of its semi-major axis, and this can be determined as follows:

[0099]

[0100] The rotation angle α(t) is calculated according to the following formula.

[0101]

[0102] The time-varying center of the ellipse as it moves with the vehicle can be calculated using the following formula.

[0103]

[0104] in, Let X be the current position of the preset scatterer in the channel delay path at time t. C (t) is the time-varying center of the ellipse as it moves with the vehicle.

[0105] Step S53: Calculate the Doppler frequency shift parameters at each time step based on the Doppler frequency shift parameters at the initial time step and the current position of the preset scatterer in the channel delay path at each time step.

[0106] For example, formula (3) can be calculated using formulas (9) and (10) above.

[0107] In one specific implementation, such as Figure 6 As shown, step S51 above, based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time, calculates the Doppler frequency shift parameters at the initial time, including:

[0108] Step S61: Based on the two-dimensional elliptical channel model at the initial moment and the measured channel parameters at each moment, calculate the current position of the preset scatterer in the channel delay path at the initial moment.

[0109] The measured channel parameters at each moment are obtained by measuring the current speeds of the transmitting and receiving vehicles in real time within the two-dimensional elliptical channel model at each moment, and then calculating x using the formulas (1) and (2) above. t (t), x r (t), based on the two-dimensional elliptic channel model at each time point, substituting x t (t), x r (t) Calculate the current position of the preset scatterer in the channel delay path at the initial time.

[0110] For example, the current position of the preset scatterer in the channel delay path at the initial moment is calculated by the following formula:

[0111]

[0112] X represents the current position of the preset scatterer in the channel delay path at the initial moment. c (0) is the center of the ellipse at the initial moment.

[0113] Step S62: Based on the current position of the preset scatterer in the channel delay path at the initial time and the measured channel parameters at each time, calculate the Doppler frequency shift parameters at the initial time.

[0114] For example, formula (9) is obtained by combining the vehicle position and velocity vector at the initial moment with the above formula (13). The measured parameter is the measured current speed of the transmitting and receiving vehicles. Based on the measured current speed of the transmitting and receiving vehicles, the current position of the transmitting and receiving vehicles can be further obtained.

[0115] For example, based on the above formulas (1) and (2), the velocity vector of the transmitting vehicle is: velocity vector of the receiving vehicle d K(X,t) represents the total distance the signal travels from the transmitting vehicle, through the scatterer, to the receiving vehicle, which can be expressed as:

[0116] d K (X,t)=d t (X,t)+d r (X,t) (14);

[0117] Where, d t (X,t)=||XX t (t)|| represents the distance from the transmitting vehicle to the scatterer, while d r (X,t)=||XX r (t)|| is the distance from the scatterer to the receiving vehicle, and its time delay τ K (X,t)=d K (X,t) / c, where c is the speed of light.

[0118] The position of different scattering bodies leads to different Doppler frequency shifts. For any time t n Doppler frequency shift f d This can be expressed as the following formula:

[0119]

[0120] Where β is the angle between the velocity vector of the transmitting vehicle and the line connecting the scatterer. It is the angle between the vehicle velocity vector at the receiving end and the line connecting the scatterer. From the above formula (15), it can be seen that the two variables of the Doppler frequency shift are β.

[0121] A simple derivation of the formula τ K (X,t)=d K (X,t) / c, we can find τ K (X,t) will change with the motion.

[0122]

[0123] Using the above formulas (1) and (2), we can obtain the following formula:

[0124]

[0125] Among them, e t =(XX) t (t)) / ||XX t (t)|| and e r =(XX) r (t)) / ||XX r (t)||,e tLet e ​​be the unit vector pointing from the emitter to the scatterer. r This represents the unit vector pointing from the receiver to the scatterer.

[0126] Considering the change in spatial distance d t (X,t), d r (X,t) is a function of X in the above formula xr(t)=xr0+vrt(2). Calculate d t (X,t) and d r The gradient of (X,t) with respect to X is given by the following formula:

[0127]

[0128] Substituting formula (18) into formula (16) yields the following formula:

[0129]

[0130] Formulas (17) and (19) above have the same mathematical meaning. Substituting formula (19) into formula (16), the Doppler frequency shift can be expressed as follows:

[0131]

[0132] Therefore, the time derivative of the path length in the above formula (16) can be represented by the spatial derivative d. t (X,t) represents that d r Calculate Vt and Vr along the corresponding velocity vector (X,t).

[0133] Calculate t = t n f d (X,t), in this embodiment, we aim to calculate the time delay τ using formula (20). k (X,t n ) = τ, the Doppler frequency shift under all time delay paths, that is, in this embodiment, all scatterers with the same transmission path length need to be considered.

[0134] d K (X,t n )=d t (X,t n )+d r (X,t n )=τ K (X,t n )c=τc (21);

[0135] Here we set d K (X,t n )=2a τ , where a τ ∈[(||X t(t n )-X r (t n )||) / 2,∞). Considering d t (X,t n )+d r (X,t n Since τ is a constant, therefore, K (X,t n An ellipse containing the same time-delayed scatterer is called a delay ellipse, and its parameter is τ.

[0136] Using the theory of elliptic geometry, we can obtain a major axis of a. τ short axis b τ The calculation formulas for both are as follows:

[0137]

[0138] Define X C (t n ) = X t (t n )+X r (t n ) / 2 is the center of the time delay ellipse. Further calculations can yield the above formula (13).

[0139] Step S13: Based on the measured channel parameters at each time point and the Doppler power spectrum characteristic parameters at each time point, calculate the channel scattering function at each time point to correct the corresponding two-dimensional elliptical channel model.

[0140] In one specific implementation, step S13 above, calculating the channel scattering function at each time moment to correct the two-dimensional elliptical channel model at each time moment, is performed by the following formula:

[0141]

[0142]

[0143] Where S(τ, f) d ( ) represents the channel scattering function at each time step. Let p(f) be the time-delay domain energy characteristic parameter at each time step. d |τ i f represents the Doppler power spectrum characteristic parameters at each time point. d Let τ be the Doppler frequency shift parameter at each time step, and τ be the time delay parameter in the channel delay path at each time step. iLet be the delay parameter in the channel delay path at time i, and be the corrected Doppler power spectrum characteristic parameters at each time. Therefore, the Doppler power spectrum of the two-dimensional elliptical channel model at each time is corrected by the above formulas (23) and (24) to ensure that the two-dimensional elliptical channel model at each time is more accurate.

[0144] Therefore, the two-dimensional modeling method for vehicle-to-vehicle broadband communication channels in this embodiment only involves the vehicle motion state in a two-dimensional plane, which can significantly simplify the modeling process. Furthermore, the two-dimensional elliptical channel model is corrected based on the channel scattering function obtained at each time step using the measured channel parameters at each time step, thereby improving the accuracy of the modeling.

[0145] In a specific example, such as Figure 7 The figure shows the time-delay domain energy characteristic parameters of the measured channel parameters at each time point. It indicates the time-delay power spectrum of the channel, the energy characteristics of reflection or scattering under different time-delay paths, and is used to correct the energy domain characteristics of Doppler spread under different time delays.

[0146] like Figure 8 The image shows a schematic diagram of a time-domain channel Doppler power spectrum simulation. Figure 7 By correcting the modeled Doppler power spectrum using the measured time-delay domain energy characteristic parameters at each moment, we can obtain... Figure 8 A schematic diagram of the simulation of the Doppler power spectrum of the channel in the mid-time domain.

[0147] like Figure 9 The figure shows a schematic diagram of the channel time-domain Doppler power spectrum corrected by simulation based on the channel scattering function at each time point. Figure 10 The simulation results are presented after corrections for channel attenuation and multipath energy attenuation.

[0148] Based on the same concept, this embodiment also provides a two-dimensional modeling device for vehicle-to-vehicle broadband communication channels, such as... Figure 10 As shown, it includes the following modules:

[0149] The channel model creation module 101 is used to create a two-dimensional elliptical channel model at each moment in real time with the current position of the transmitting vehicle and / or the receiving vehicle as the focus during the movement of the transmitting vehicle and / or the receiving vehicle. In the two-dimensional elliptical channel model at each moment, the signals sent from the transmitting vehicle to the receiving vehicle are reflected by a preset scatterer to form the channel transmission path at each moment.

[0150] The Doppler power spectrum calculation module 102 is used to calculate the Doppler power spectrum characteristic parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time.

[0151] The channel scattering function correction module 103 is used to calculate the channel scattering function at each time based on the measured channel parameters and the Doppler power spectrum characteristic parameters at each time, so as to correct the two-dimensional elliptical channel model at each time.

[0152] In one specific implementation, the Doppler power spectrum calculation module 102 includes:

[0153] The Doppler frequency shift calculation submodule is used to calculate the Doppler frequency shift parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time.

[0154] The probability density calculation submodule is used to calculate the probability density parameters of the preset scatterers in the channel delay path at each time based on the two-dimensional elliptical channel model at each time.

[0155] The Doppler power spectrum calculation submodule is used to calculate the Doppler power spectrum characteristic parameters at each time based on the Doppler frequency shift parameters at each time and the probability density parameters of the preset scatterers in the channel delay path at each time.

[0156] In one specific implementation, the Doppler frequency shift calculation submodule includes:

[0157] The initial Doppler frequency shift calculation unit is used to calculate the initial Doppler frequency shift parameters based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time.

[0158] The preset scatterer current position calculation unit is used to calculate the current position of the preset scatterer in the channel delay path at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time.

[0159] The Doppler frequency shift calculation unit at each time moment is used to calculate the Doppler frequency shift parameters at each time moment based on the Doppler frequency shift parameters at the initial time moment and the current position of the preset scatterer in the channel delay path at each time moment.

[0160] In one specific implementation, the Doppler frequency shift calculation unit at the initial moment includes:

[0161] The first calculation subunit is used to calculate the current position of the preset scatterer in the channel delay path at the initial time based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time.

[0162] The second calculation subunit is used to calculate the Doppler frequency shift parameters at the initial time based on the current position of the preset scatterer in the channel delay path at the initial time and the measured channel parameters at each time.

[0163] The channel scattering function correction module 103 calculates the channel scattering function at each time point to correct the corresponding two-dimensional elliptical channel model by performing the above formulas (23) and (24).

[0164] The modules and units of the two-dimensional modeling device for the vehicle-to-vehicle broadband communication channel in this embodiment have been described in the above method and will not be repeated here. This device only involves the vehicle motion state in a two-dimensional plane, which can significantly simplify the modeling process. Furthermore, based on the measured channel parameters at each time moment, the corresponding two-dimensional elliptical channel model is corrected by obtaining the channel scattering function at each time moment, thereby improving the accuracy of the modeling.

[0165] This embodiment also provides a computer device, such as... Figure 11 As shown, the computer device may include a processor 111 and a memory 112, wherein the processor 111 and the memory 112 may be connected via a bus or other means. Figure 11 Taking the example of a connection between China and Israel via a bus.

[0166] Processor 111 can be a central processing unit (CPU). Processor 111 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.

[0167] The memory 112, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules. The processor 111 executes various functional applications and data processing by running the non-transitory software programs, instructions, and modules stored in the memory 112, thereby realizing the two-dimensional modeling method for the vehicle-to-vehicle broadband communication channel in the above embodiment.

[0168] The memory 112 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 111, etc. Furthermore, the memory 112 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 112 may optionally include memory remotely located relative to the processor 111, and these remote memories may be connected to the processor 111 via a network. Examples of such networks include, but are not limited to, power grids, the Internet, enterprise intranets, local area networks, mobile communication networks, and combinations thereof.

[0169] The one or more modules are stored in the memory 112, and when executed by the processor 111, they execute the two-dimensional modeling method of the vehicle-to-vehicle broadband communication channel in the embodiment shown in the figure.

[0170] The specific details of the above-mentioned computer equipment can be understood by referring to the relevant descriptions and effects in the embodiments shown in the accompanying drawings, and will not be repeated here.

[0171] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0172] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A two-dimensional modeling method for a vehicle-to-vehicle broadband communication channel, characterized in that, Includes the following steps: During the movement of the transmitting vehicle and / or the receiving vehicle, a two-dimensional elliptical channel model is created in real time with the current position of the transmitting vehicle and the receiving vehicle as the focus. In the two-dimensional elliptical channel model at each moment, the signal sent by the transmitting vehicle to the receiving vehicle is reflected by a preset scatterer to form the channel transmission path at each moment. Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the Doppler power spectrum characteristic parameters at each time point are calculated; the Doppler frequency shift parameters at each time point are calculated using the following formula: in, Let be the Doppler frequency shift parameter at time t. The current position of the preset scatterer in the channel delay path at time t. Let x be the X-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. Let Y be the Y-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. Let X be the X-axis parameter at time t in the Cartesian coordinate system. Here are the Y-axis parameters at time t in the Cartesian coordinate system. The center frequency of the channel. At the speed of light, The velocity vector of the transmitter along the X-axis. The velocity vector along the Y-axis of the transmitting end. The velocity vector along the X-axis of the receiving end. The velocity vector along the Y-axis of the receiving end; Based on the measured channel parameters and Doppler power spectrum characteristics at each time point, the channel scattering function at each time point is calculated to correct the corresponding two-dimensional elliptical channel model.

2. The two-dimensional modeling method for vehicle-to-vehicle broadband communication channels according to claim 1, characterized in that, The calculation of Doppler power spectrum characteristic parameters at each time point, based on the two-dimensional elliptical channel model and the measured channel parameters at each time point, includes: Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the Doppler frequency shift parameters at each time point are calculated. Based on the two-dimensional elliptical channel model at each time point, the probability density parameters of the preset scatterer in the channel delay path at each time point are calculated. Based on the Doppler frequency shift parameters at each time point and the probability density parameters of the preset scatterer in the channel delay path at each time point, the Doppler power spectrum characteristic parameters at each time point are calculated.

3. The two-dimensional modeling method for vehicle-to-vehicle broadband communication channels according to claim 2, characterized in that, The calculation of the Doppler frequency shift parameters at each time point, based on the two-dimensional elliptical channel model and the measured channel parameters at each time point, includes: Based on the two-dimensional elliptical channel model at the initial moment and the measured channel parameters at each moment, the Doppler frequency shift parameters at the initial moment are calculated. Based on the two-dimensional elliptical channel model at each time point and the measured channel parameters at each time point, the current position of the preset scatterer in the channel delay path at each time point is calculated; Based on the Doppler frequency shift parameters at the initial time and the current position of the preset scatterer in the channel delay path at each time, the Doppler frequency shift parameters at each time are calculated.

4. The two-dimensional modeling method for vehicle-to-vehicle broadband communication channels according to claim 3, characterized in that, The calculation of the Doppler frequency shift parameters at the initial time, based on the two-dimensional elliptical channel model at the initial time and the measured channel parameters at each time, includes: Based on the two-dimensional elliptical channel model at the initial moment and the measured channel parameters at each moment, calculate the current position of the preset scatterer in the channel delay path at the initial moment; Based on the current position of the preset scatterer in the channel delay path at the initial moment and the measured channel parameters at each moment, the Doppler frequency shift parameter at the initial moment is calculated.

5. The two-dimensional modeling method for vehicle-to-vehicle broadband communication channels according to claim 2, characterized in that, The calculation of the channel scattering function at each time point to correct its corresponding two-dimensional elliptical channel model is performed by the following formula: ； ； in, Let be the channel scattering function at each of the given times. These are the time-delay domain energy characteristic parameters at each time step. The Doppler power spectrum characteristic parameters at each time point are... The Doppler frequency shift parameters at each time point are given. These are the time delay parameters in the channel time delay path at each time point. for The time delay parameters in the channel delay path at time t. These are the corrected Doppler power spectrum characteristic parameters for each time point.

6. The two-dimensional modeling method for vehicle-to-vehicle broadband communication channels according to any one of claims 1 to 5, characterized in that, Calculating the current positions of the transmitting vehicle and the receiving vehicle includes: The initial position and current speed of the transmitting vehicle and the receiving vehicle are acquired in real time. The current positions of the transmitting vehicle and the receiving vehicle are calculated based on their initial positions and current speeds.

7. A two-dimensional modeling device for a vehicle-to-vehicle broadband communication channel, characterized in that, Includes the following modules: The channel model creation module is used to create a two-dimensional elliptical channel model at each moment in real time, with the current position of the transmitting vehicle and / or the receiving vehicle as the focus, during the movement of the transmitting vehicle and / or the receiving vehicle. In the two-dimensional elliptical channel model at each moment, the signals sent by the transmitting vehicle to the receiving vehicle are reflected by a preset scatterer to form the channel transmission path at each moment. The Doppler power spectrum calculation module is used to calculate the Doppler power spectrum characteristic parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time. The Doppler frequency shift parameters at each time point are calculated using the following formula: in, Let be the Doppler frequency shift parameter at time t. The current position of the preset scatterer in the channel delay path at time t. Let x be the X-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. Let Y be the Y-axis coordinate of the preset scatterer in the Cartesian coordinate system in the channel delay path at time t. Let X be the X-axis parameter at time t in the Cartesian coordinate system. Here are the Y-axis parameters at time t in the Cartesian coordinate system. The center frequency of the channel. For the speed of light, The velocity vector of the transmitter along the X-axis. The velocity vector along the Y-axis of the transmitting end. The velocity vector along the X-axis of the receiving end. The velocity vector along the Y-axis of the receiving end; The channel scattering function correction module is used to calculate the channel scattering function at each time point based on the measured channel parameters and the Doppler power spectrum characteristic parameters at each time point, so as to correct the corresponding two-dimensional elliptical channel model.

8. The two-dimensional modeling device for vehicle-to-vehicle broadband communication channels according to claim 7, characterized in that, The Doppler power spectrum calculation module includes: The Doppler frequency shift calculation submodule is used to calculate the Doppler frequency shift parameters at each time based on the two-dimensional elliptical channel model at each time and the measured channel parameters at each time. The probability density calculation submodule is used to calculate the probability density parameters of the preset scatterer in the channel delay path at each time based on the two-dimensional elliptical channel model at each time. The Doppler power spectrum calculation submodule is used to calculate the Doppler power spectrum characteristic parameters at each time based on the Doppler frequency shift parameters at each time and the probability density parameters of the preset scatterer in the channel delay path at each time.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute the two-dimensional modeling method for the vehicle-to-vehicle broadband communication channel as described in any one of claims 1 to 6.

10. A computer device, characterized in that, include: The system includes a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the two-dimensional modeling method for the vehicle-to-vehicle broadband communication channel as described in any one of claims 1 to 6.

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