Method for analyzing birth-death characteristics of scattering clusters in vacuum tube maglev train scene

Abstract

The application provides a method for analyzing the birth-death characteristics of scattering clusters in a vacuum tube maglev train scene. The method comprises the following steps: building a random geometry model in the vacuum tube maglev train scene, and representing the coordinates of the transmitting and receiving antennas of the maglev train and the scattering points in the model; establishing the birth-death concept of the scattering clusters based on the random geometry model of the vacuum tube, obtaining the statistical model of the birth-death characteristics of the scattering clusters in the vacuum tube maglev train scene; deriving the cluster center distribution of the scattering clusters according to the statistical model of the birth-death characteristics of the scattering clusters, and generating the distribution characteristics of the scattering points based on the cluster center; representing the distribution characteristics of the scattering points as the distribution probability of the angle, and generating the correlation function of the birth-death characteristics of the scattering clusters according to the distribution probability of the angle. The application can effectively capture the instantaneous dynamic characteristics and long-term statistical trend of the multipath clusters, and provide more actual channel modeling basis for the link design and performance evaluation of the wireless communication system of the vacuum tube maglev train.

Description

Technical Field

[0001] This invention relates to the field of vacuum tube maglev train technology, and in particular to a method for analyzing the generation and extinction characteristics of scattering clusters in a vacuum tube maglev train scenario based on a Geometry Based Stochastic Modeling (GBSM). Background Technology

[0002] Vacuum tube maglev trains, as a strategic transportation mode, are leading the transformation of ground transportation systems due to their ultra-high speed, low energy consumption, and high efficiency. This train operates within a cylindrical, narrow, low-vacuum metal tube, achieving supersonic "near-ground flight" through superconducting magnetic levitation technology in conjunction with the vacuum environment. Its reliable operation heavily relies on a stable and efficient vehicle-to-ground wireless communication system, which must handle train control commands, safety monitoring data transmission, and high-speed internet access for passengers.

[0003] In recent years, China has made several breakthroughs in the field of vacuum tube magnetic levitation: Southwest Jiaotong University has built a prototype testing platform and a multi-mode coupled dynamic test platform for rail transit; China Aerospace Science and Industry Corporation has built a high-speed train test line in Datong, Shanxi Province, and completed system integration demonstration and verification under low vacuum conditions. However, existing research mainly focuses on the power and transportation fields, and research on wireless communication channel modeling is still insufficient.

[0004] In the unique communication environment of a vacuum tube, traditional mobile communication theory faces unprecedented technical challenges. The enclosed metal tube structure forms a natural electromagnetic waveguide, causing significant waveguide effects during radio wave transmission. This effect results in a path loss exponent that is significantly lower than that of the free-space propagation model. Furthermore, the cylindrical geometry of the tube makes the propagation trajectories of multipath signals highly similar, producing a significant keyhole effect, which severely restricts the performance of large-scale MIMO (Multiple-Input Multiple-Output) systems.

[0005] When a train travels at speeds approaching 1000 km / h, the immense relative velocity triggers an extreme Doppler shift effect. The relative positions of the transmitting and receiving devices change drastically within milliseconds, causing rapid switching of the visible area of ​​scatterers within the tube. This results in strong non-stationary characteristics in the channel response in both the time and spatial domains. A 5G communication link that performs stably in a traditional high-speed railway tunnel environment exhibits severe performance degradation in a vacuum tube simulation scenario, with the system bit error rate rising sharply to the critical level of communication interruption within 0.5 seconds. This demonstrates that traditional channel models based on open-space propagation environments or low-speed movement scenarios are no longer able to accurately describe the electromagnetic wave propagation characteristics under high-speed operation in a vacuum tube.

[0006] Current wireless channel modeling methods are divided into deterministic models and stochastic models: deterministic models have high accuracy but high computational complexity and are suitable for simple scenarios; stochastic models describe the environment by randomly distributing scattering points, and have strong universality and low computational complexity.

[0007] GBSM, as a commonly used stochastic model, combines geometric constraints and statistical distribution modeling to simultaneously characterize the spatial distribution of scatterers and the temporal evolution of the channel, making it suitable for dynamic propagation scenarios with deterministic structural constraints. Furthermore, the introduction of the cluster concept can characterize the aggregation characteristics of multipath signals in the time delay and angular domains, but further dynamic observation of the cluster evolution process with train position is required.

[0008] Currently, there is no effective method for modeling the birth and death channels of scattering clusters based on a geometric random scattering model in the scenario of vacuum tube maglev trains. Summary of the Invention

[0009] The embodiments of the present invention provide a method for analyzing the generation and extinction characteristics of scattering clusters in a vacuum tube maglev train scenario, so as to effectively perform channel modeling for wireless communication system links in a vacuum tube maglev train scenario.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] A method for analyzing the generation and extinction characteristics of scattering clusters in a vacuum tube maglev train scenario, comprising: A stochastic geometric model is constructed for the scenario of a vacuum tube maglev train, and the coordinates of the transmitting and receiving antennas and scattering points of the maglev train are represented in the stochastic geometric model. Based on the random geometric model of the vacuum pipe, the concept of the birth and death of scattering clusters is established, and a statistical model of the birth and death characteristics of scattering clusters in the vacuum pipe maglev train scenario is obtained. Based on the statistical model of the birth and death characteristics of the scattering clusters, the distribution of the cluster centers of the scattering clusters is derived, and the distribution characteristics of the scattering points are generated with the cluster centers as the reference. The distribution characteristics of scattering points are represented as the distribution probability of angles, and a correlation function for the birth and death characteristics of scattering clusters is generated based on the distribution probability of angles.

[0012] Preferably, the construction of the random geometric model for the vacuum tube maglev train scenario, wherein the coordinates of the maglev train's transmitting and receiving antennas and scattering points are represented in the random geometric model, includes: Assuming the vacuum tube maglev train uses a 2×2 antenna system, and a Cartesian coordinate system is established with the central axis of the cylindrical vacuum tube as the y-axis and the direction of the maglev train's travel as the positive direction, the transmitting antenna of the maglev train... Located at the top of the inner side of the pipe, the receiving antenna of the maglev train Located on the train, the coordinates of the transmitting and receiving antennas are:

[0013] in , , , These are the coordinates of the q-th and p-th antennas at the transmitting and receiving ends, respectively. The element spacing between the transmitting and receiving ends is as follows: and The angles between the transmitting and receiving antenna arrays and the direction of train movement are respectively and The initial distance between the transmitting and receiving antennas is L, the running speed is v, and the heights of the transmitting and receiving antennas are respectively... and The scattering point is denoted as That is, the coordinates of the scattering point satisfy the formula:

[0014] Where x and z represent the coordinate components of the scattering point on the x-axis and z-axis in the Cartesian coordinate system, respectively, and R is the radius of the vacuum pipe. The method of equal area and the law of cosines are used to derive the... and The coordinates are represented by the following formula:

[0015] in and Representing links respectively For pitch and horizontal angles, considering single-hop propagation, the channel impulse response includes line-of-sight (LOS) components and non-line-of-sight (NLOS) components, expressed as:

[0016] in The direct component of the LOS radius, The non-direct components of the NLOS radius are expressed as follows:

[0017] in, For total energy, For wavelength, The K-factor of the link, Indicates the number of scattering paths. It is the phase offset, in Follows a uniform distribution. Indicates direct link distance, and These represent non-direct links. and distance, and These correspond to the Doppler frequency shifts of the direct and indirect components, respectively:

[0018] Preferably, the step of establishing the concept of the birth and death of scattering clusters based on the random geometric model of the vacuum pipe, and obtaining a statistical model of the birth and death characteristics of scattering clusters in the vacuum pipe maglev train scenario, includes: Based on the stochastic geometric model of the vacuum pipe at the initial time An initial scattering cluster is generated, and the number of the initial scattering clusters is denoted as N(t0). The calculation formula is as follows:

[0019] in The generation rate of the scattering clusters, The initial number of scattering clusters is represented by the generation rate and the destruction rate, where represents the rate of cluster formation and the rate of cluster destruction. The birth and death of scattering clusters depends on their time-based survival probability. Specifically, it is expressed as:

[0020] in By modeling the time-dependent distance constant for time-nonstationary scattering clusters, the statistical model of the birth-death characteristics of scattering clusters is obtained as follows:

[0021] in It's the probability of survival over time. The generation rate of the scattering clusters, The denoted value represents the rate of scattering cluster demise.

[0022] Preferably, the step of deriving the cluster center distribution of the scattering cluster based on the statistical model of the birth and death characteristics of the scattering cluster, and generating the distribution characteristics of the scattering points based on the cluster center, includes: Based on the time survival probability of the scattering cluster , generation rate of scattering clusters and the rate of scattering clusters Establish scattering clusters, and define each scattering cluster as containing M scattering points; A random offset dy is added along the pipe axis. The value of the random offset dy ranges from the maximum grid side length. Decision, and It is calculated using physical constraint formulas; The value used is the minimum Euclidean distance from the center of the scattering cluster to the transmitting and receiving antennas. It is the wavelength; In the angular dimension, angular offset Calculate the original azimuth angle of the scattering cluster center based on the arc length offset along the circumference of the pipe. :

[0023] Apply random angular offset This forms a new azimuth angle for the center of the scattering cluster:

[0024] The spatial angular characteristics of each scattering point after double offset constraint are characterized by two parameters: and A scattering cluster is initialized on the inner wall of the vacuum pipe, and the coordinates of the center of the scattering cluster are obtained by transforming the cylindrical coordinate system to the Cartesian coordinate system. ;

[0025] The y-axis follows a uniform distribution in the range [-L, 0], and the angle... obey The uniform distribution on the surface, based on the cluster center, generates scattering points and records the initial channel state; Set minimum update interval The process involves updating the transceiver coordinates, determining the life-or-death status of scattering clusters based on their survival probability, generating scattering points and updating the channel state for surviving scattering clusters, and iterating the scattering point update process repeatedly until a set deadline is reached. This process forms a complete cluster center distribution sequence for the scattering clusters, and generates the distribution characteristics of the scattering points based on the cluster centers. These distribution characteristics include angles. and probability density function and .

[0026] Preferably, the step of representing the distribution characteristics of scattering points as the distribution probability of angles, and generating a correlation function for the birth and death characteristics of the scattering cluster based on the distribution probability of angles, includes: Channel impulse response between links p and q and between links p' and q' and For example, the spatiotemporal correlation function of the birth and death characteristics of a scattering cluster is:

[0027] in This represents the total energy between links p and q. Let p'q be the total energy of link p'q. It is the link pq channel CIR. yes The conjugate; The spatiotemporal correlation function of the birth and death characteristics of a scattering cluster is expressed as:

[0028] in This refers to the correlation function of the LOS path. This refers to the NLOS path correlation function, where the distances between the transmitting and receiving array elements are respectively... and ; The spatiotemporal correlation function of the birth and death characteristics of the scattering clusters of the LOS path is expressed as:

[0029] in It is the link K factor. It is the direct path of link PQ. It is the direct path of link p'q. It is the Doppler frequency offset of the link pq. It is the Doppler frequency offset of link p'q; The spatiotemporal correlation function of the birth and death characteristics of scattering clusters along the NLOS path is expressed as:

[0030] in, and They are and Probability density function.

[0031] As can be seen from the technical solutions provided by the embodiments of the present invention above, the method of the present invention can effectively capture the instantaneous dynamic characteristics and long-term statistical trends of multipath clusters, providing a channel modeling basis that is closer to the actual situation for the link design and performance evaluation of the vacuum tube maglev train wireless communication system.

[0032] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1This is a schematic diagram illustrating the implementation principle of a method for analyzing the birth and death characteristics of scattering clusters in a vacuum tube maglev train scenario based on a geometric random scattering model, provided by an embodiment of the present invention. Figure 2 The flowchart illustrates a method for analyzing the birth and death characteristics of scattering clusters in a vacuum tube maglev train scenario based on a geometric random scattering model, as provided in an embodiment of the present invention. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0036] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0037] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0038] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0039] A scattering cluster refers to a group of spatially adjacent scatterers (such as buildings, terrain features, or microscopic particles) that collectively scatter an incident wave during wireless communication channels or physical scattering processes, forming observable or modelable signal components. In wireless communication, scattering clusters are a core concept in channel modeling. Channel modeling uses mathematical methods to characterize the propagation characteristics of wireless signals, and the scattering cluster model clusters scatterers in the environment into multiple clusters, each cluster corresponding to a time-delay path, thereby simulating multipath effects.

[0040] This invention provides a spatial distribution probability model of scatterers adapted to the cylindrical closed structure of a vacuum pipe, capable of characterizing the spatial distribution law of scatterers on the inner wall of the pipe; it establishes a dynamic generation and extinction mechanism for scattering clusters, simultaneously capturing the instantaneous dynamic characteristics and long-term statistical trends of multipath clusters, adapting to the strong non-stationary characteristics of the channel caused by the ultra-high-speed movement of trains; it derives the spatiotemporal autocorrelation function of the channel combining the synergistic effect of the pipe structure and high-speed movement, revealing the inherent law of the time-varying characteristics of the channel and improving the modeling accuracy; it optimizes the generation mechanism of scattering points within clusters, ensuring through physical constraints that the distribution of scattering points is consistent with the actual electromagnetic wave propagation law. Ultimately, it provides a high-precision, highly adaptable channel modeling method for the vacuum pipe maglev train scenario, providing a realistic channel modeling basis for the link design and performance evaluation of wireless communication systems in this scenario.

[0041] The implementation principle diagram of the method for analyzing the birth and death characteristics of scattering clusters in a vacuum tube magnetic levitation train scenario based on a geometric random scattering model provided by this invention is shown in the figure below. Figure 1 As shown, the specific processing flow is as follows: Figure 2 As shown, the processing steps include the following: Step S10: Construct a random geometric model of the vacuum pipe, and represent the coordinates of key information such as the transmitting and receiving antennas and scattering points in the random geometric model to provide a modeling foundation for the following text.

[0042] Step S20: Derivation of the physical statistical model of the birth and death characteristics of scattering clusters. Based on the stochastic geometric model of the vacuum pipe described above, the concept of the birth and death of scattering clusters is established, and a statistical model of the birth and death characteristics of scattering clusters under the current environment is obtained, providing statistical indicators for the cluster center generation in step S30.

[0043] Step S30: Generation and death of scattering cluster centers and distribution characteristics of scattering points. Based on the statistical model of the generation and death characteristics of scattering clusters obtained in Step S20, the distribution of scattering cluster centers is derived, and the distribution characteristics of scattering points are generated using the cluster centers as a reference.

[0044] Step S40: Derivation of the statistical properties of the channel correlation function. The distribution characteristics of the scattering points obtained in step S30 are expressed as the probability distribution of angles. Based on the probability distribution of angles, a correlation function for the birth and death characteristics of the scattering clusters is generated.

[0045] Step S10 above specifically includes: assuming a 2×2 antenna system, establishing a Cartesian coordinate system with the central axis of the cylindrical vacuum tube as the y-axis and the direction of the maglev train's movement as the positive direction. Considering the downlink train-to-ground communication link, the transmitting antenna of the maglev train (denoted as...) Located at the top of the inner side of the pipe, the receiving antenna of the maglev train (denoted as...) Located on the train, the coordinates of the transmitting and receiving antennas are:

[0046] in , , , These are the coordinates of the q-th and p-th antennas at the transmitting and receiving ends, respectively. The element spacing between the transmitting and receiving ends is as follows: and The angles between the transmitting and receiving antenna arrays and the direction of train movement are respectively and The initial distance between the transmitting and receiving antennas is L, the operating speed is v, and the heights of the transmitting and receiving antennas are respectively... and The scattering point is denoted as That is, the coordinates of the scattering point satisfy the formula:

[0047] Where x and z represent the coordinate components of the scattering point on the x-axis and z-axis in the Cartesian coordinate system, respectively, and R is the radius of the vacuum pipe. The method of equal area and the law of cosines can be used to derive the formula... and The coordinates are represented by the following formula:

[0048] in and Representing links respectively The pitch and horizontal angles, as expressed in this equation, represent the ensemble stochastic modeling and provide the coordinates of the scattering point for geometric modeling, laying the foundation for subsequent modeling. Considering single-hop propagation, the channel impulse response includes LOS (Line of Sight) and NLOS (Non-Line of Sight) components, which can be expressed as:

[0049] in For direct fire, For non-direct paths, they can be represented as follows:

[0050] in, For total energy, For wavelength, The K-factor of the link, Indicates the number of scattering paths. It is the phase offset, in Follows a uniform distribution. Indicates direct link distance, and These represent non-direct links. and The distance provides a formula for the subsequent derivation of the correlation of S04. and These correspond to the Doppler frequency shifts of the direct and indirect components, respectively:

[0051] The geometric framework established in this step allows for the analysis of scattering clusters.

[0052] In step S20 above, the generation and destruction rates and time-dependent distance constants of the scene are input, and the statistical characteristics of the scattering clusters are output.

[0053] Specifically, this includes: at the initial moment An initial scattering cluster is generated, and the number of the initial scattering clusters is denoted as N(t0). The calculation formula is as follows:

[0054] in The generation rate of the scattering clusters, The initial number of scattering clusters is represented by the generation rate and the destruction rate, which mainly depend on the velocity magnitude.

[0055] Furthermore, the number of scattering clusters changes with the change of t, and the birth and death of scattering clusters depends on the time survival probability. Specifically, it can be expressed as:

[0056] in The time-dependent distance constant for modeling the time nonstationarity of scattering clusters affects this modeling. The number of scattering clusters changes over time, resulting in the following statistical model of the clusters' birth and death characteristics:

[0057] in It's the probability of survival over time. The generation rate of the scattering clusters, The denoted value represents the rate of scattering cluster demise.

[0058] In step S30 above, the statistical characteristics of the birth and death characteristics of the scattering clusters from step S20 are input, and the distribution of scattering points and the angular probability distribution are output.

[0059] Specifically, this includes: establishing a scattering cluster based on the statistical model of the birth and death characteristics of the scattering cluster shown in Equation (11), setting each scattering cluster to contain M scattering points, and generating scattering points using double offset constraints.

[0060] A random offset dy is added along the pipe axis. The value of the random offset dy ranges from the maximum grid side length. Decision, and It is calculated using physical constraint formulas.

[0061] The value used is the minimum Euclidean distance from the center of the scattering cluster to the transmitting and receiving antennas. It is the wavelength.

[0062] Furthermore, in the angular dimension, the angular offset This actually corresponds to the arc length offset along the circumference of the pipe. Calculate the original azimuth angle of the scattering cluster center. :

[0063] Furthermore, apply random angular offset. This forms a new azimuth angle for the center of the scattering cluster:

[0064] After applying dual offset constraints, the spatial angular characteristics of each scattering point are characterized by two parameters, namely... and This provides the basic spatial parameters for the subsequent calculation of the spatiotemporal correlation function.

[0065] Furthermore, a scattering cluster is initialized on the inner wall of the vacuum pipe, and the coordinates of the center of the scattering cluster are obtained by transforming the cylindrical coordinate system to the Cartesian coordinate system. .

[0066]

[0067] The y-axis follows a uniform distribution in the range [-L, 0], and the angle... obey The uniform distribution on the surface, the scattering points are generated based on the cluster center and the initial channel state is recorded.

[0068] Furthermore, set a minimum update interval. The process involves updating environmental information such as the coordinates of the transmitting and receiving ends, determining the life-or-death status of scattering clusters based on their survival probability, generating scattering points and updating the channel state for surviving scattering clusters, and iterating the scattering point update process repeatedly until a set deadline is reached. This process forms a complete cluster center distribution sequence for the scattering clusters, and generates the distribution characteristics of the scattering points based on the cluster centers. These distribution characteristics include angles. and probability density function and and the probability density function and Substitute the relevant function formula into step S40.

[0069] The above step S40 uses the channel impulse response between links p and q and link p'q'. and For example, the spatiotemporal correlation function of the birth and death characteristics of a scattering cluster can be written as:

[0070] in This represents the total energy between links p and q. Let p'q be the total energy of link p'q. It is the link pq channel CIR. yes . conjugate.

[0071] The spatiotemporal correlation function of the birth and death characteristics of scattering clusters can be compared with the channel impulse response, and its expression can be regarded as:

[0072] in This refers to the correlation function of the LOS path. This refers to the NLOS path correlation function, where the distances between the transmitting and receiving array elements are respectively... and .

[0073] The spatiotemporal correlation function of the birth and death characteristics of the scattering clusters of the LOS path can be expressed as:

[0074] in It is the link K factor. It is the direct path of link PQ. It is the direct path of link p'q. It is the Doppler frequency offset of the link pq. It is the Doppler frequency offset of link p'q.

[0075] The spatiotemporal correlation function of the birth and death characteristics of scattering clusters along the NLOS path can be expressed as:

[0076] in, and They are and The probability density function. The spatiotemporal correlation function of the birth and death characteristics of the aforementioned scattering clusters obtained here can be used to analyze and design the architecture of communication systems and the antenna optimization design in this scenario.

[0077] In summary, the method of the present invention has the following advantages compared with the traditional GBSM model: First, it has stronger scene adaptability. It constructs a spatial distribution model of scatterers in a cylindrical structure of a vacuum pipe, and derives the coordinates of scattering points through the geometric constraint x²+z²=R² and the equal area method. This solves the problem of distribution modeling distortion in closed pipe scenarios of traditional models and can accurately characterize the effects of waveguide effect and keyhole effect. Second, the dynamic characterization is more accurate. Through the cluster birth and death mechanism and iterative update process, the instantaneous dynamic characteristics and long-term statistical trends of multipath clusters are captured simultaneously, which perfectly adapts to the strong non-stationary characteristics of the channel caused by the ultra-high speed of train movement, and the modeling accuracy is significantly improved. Third, the statistical characteristics are more realistic. The derivation of the spatiotemporal autocorrelation function combines the synergistic effect of the pipeline structure and extreme Doppler frequency shift. Furthermore, through the optimization of angular distribution statistical fitting, the results can more realistically reflect the time-varying laws of the channel, providing a reliable basis for the design of communication systems. Fourth, the engineering applicability is higher. The model is based on the idea of ​​stochastic modeling, the computational complexity is controllable, and the simulation verification process is clear. It can be used for the link design, performance evaluation, and algorithm optimization of the wireless communication system of vacuum pipeline maglev train.

[0078] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0079] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0080] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0081] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for analyzing the birth and death characteristics of scattering clusters in a vacuum tube magnetic levitation train scenario, characterized in that, include: A stochastic geometric model is constructed for the scenario of a vacuum tube maglev train, and the coordinates of the transmitting and receiving antennas and scattering points of the maglev train are represented in the stochastic geometric model. Based on the random geometric model of the vacuum pipe, the concept of the birth and death of scattering clusters is established, and a statistical model of the birth and death characteristics of scattering clusters in the vacuum pipe maglev train scenario is obtained. Based on the statistical model of the birth and death characteristics of the scattering clusters, the distribution of the cluster centers of the scattering clusters is derived, and the distribution characteristics of the scattering points are generated with the cluster centers as the reference. The distribution characteristics of scattering points are represented as the distribution probability of angles, and a correlation function for the birth and death characteristics of scattering clusters is generated based on the distribution probability of angles.

2. The method according to claim 1, characterized in that, The aforementioned construction of a stochastic geometric model for a vacuum tube maglev train scenario, in which the coordinates of the maglev train's transmitting and receiving antennas and scattering points are represented, includes: Assuming the vacuum tube maglev train uses a 2×2 antenna system, and a Cartesian coordinate system is established with the central axis of the cylindrical vacuum tube as the y-axis and the direction of the maglev train's travel as the positive direction, the transmitting antenna of the maglev train... Located at the top of the inner side of the pipe, the receiving antenna of the maglev train Located on the train, the coordinates of the transmitting and receiving antennas are: in , , , These are the coordinates of the q-th and p-th antennas at the transmitting and receiving ends, respectively. The element spacing between the transmitting and receiving ends is as follows: and The angles between the transmitting and receiving antenna arrays and the direction of train movement are respectively and The initial distance between the transmitting and receiving antennas is L, the running speed is v, and the heights of the transmitting and receiving antennas are respectively... and The scattering point is denoted as That is, the coordinates of the scattering point satisfy the formula: Where x and z represent the coordinate components of the scattering point on the x-axis and z-axis in the Cartesian coordinate system, respectively, and R is the radius of the vacuum pipe. The method of equal area and the law of cosines are used to derive the... and The coordinates are represented by the following formula: in and Representing links respectively For the pitch and horizontal angles, considering single-hop propagation, the channel impulse response includes a line-of-sight (LOS) component and a non-line-of-sight (NLOS) component, expressed as: in The direct component of the LOS radius, The non-direct components of the NLOS radius are expressed as follows: in, For total energy, For wavelength, The K-factor of the link, Indicates the number of scattering paths. It is the phase offset, in Follows a uniform distribution. Indicates direct link distance, and These represent non-direct links. and distance, and These correspond to the Doppler frequency shifts of the direct and indirect components, respectively:

3. The method according to claim 1, characterized in that, The aforementioned statistical model for establishing the concept of the birth and death of scattering clusters based on the stochastic geometric model of the vacuum pipe, and obtaining the birth and death characteristics of scattering clusters in the vacuum pipe maglev train scenario, includes: Based on the stochastic geometric model of the vacuum pipe at the initial time An initial scattering cluster is generated, and the number of the initial scattering clusters is denoted as N(t0). The calculation formula is as follows: in The generation rate of the scattering clusters, The initial number of scattering clusters is represented by the generation rate and the destruction rate, where represents the rate of cluster formation and the rate of cluster destruction. The birth and death of scattering clusters depends on their time-based survival probability. Specifically, it is expressed as: in By modeling the time-dependent distance constant for time-nonstationary scattering clusters, the statistical model of the birth-death characteristics of scattering clusters is obtained as follows: in It's the probability of survival over time. The generation rate of the scattering clusters, The denoted value represents the rate of scattering cluster demise.

4. The method according to claim 3, characterized in that, The statistical model derived from the birth and death characteristics of the scattering clusters shows the distribution of cluster centers, and the distribution characteristics of scattering points are generated based on the cluster centers, including: Based on the time survival probability of the scattering cluster , generation rate of scattering clusters and the rate of scattering clusters Establish scattering clusters, and define each scattering cluster as containing M scattering points; A random offset dy is added to the pipe axis. The value of the random offset dy is determined by the maximum grid side length. Decision, and It is calculated using physical constraint formulas; The value used is the minimum Euclidean distance from the center of the scattering cluster to the transmitting and receiving antennas. It is the wavelength; In the angular dimension, angular offset Calculate the original azimuth angle of the scattering cluster center based on the arc length offset along the circumference of the pipe. : Apply random angular offset This forms a new azimuth angle for the center of the scattering cluster: The spatial angular characteristics of each scattering point after double offset constraint are characterized by two parameters: and A scattering cluster is initialized on the inner wall of the vacuum pipe, and the coordinates of the center of the scattering cluster are obtained by transforming the cylindrical coordinate system to the Cartesian coordinate system. ; The y-axis follows a uniform distribution in the range [-L, 0], and the angle... obey The uniform distribution on the surface, based on the cluster center, generates scattering points and records the initial channel state; Set minimum update interval The process involves updating the transceiver coordinates, determining the life-or-death status of scattering clusters based on their survival probability, generating scattering points and updating the channel state for surviving scattering clusters, and iterating the scattering point update process repeatedly until a set deadline is reached. This process forms a complete cluster center distribution sequence for the scattering clusters, and generates the distribution characteristics of the scattering points based on the cluster centers. These distribution characteristics include angles. and probability density function and .

5. The method according to claim 4, characterized in that, The aforementioned expression of the distribution characteristics of scattering points as the distribution probability of angles, and the generation of a correlation function for the birth and death characteristics of scattering clusters based on the distribution probability of angles, includes: Channel impulse response between links p and q and between links p' and q' and For example, the spatiotemporal correlation function of the birth and death characteristics of a scattering cluster is: in This represents the total energy between links p and q. Let p'q be the total energy of link p'q. It is the link pq channel CIR. yes The conjugate; The spatiotemporal correlation function of the birth and death characteristics of a scattering cluster is expressed as: in This refers to the correlation function of the LOS path. This refers to the NLOS path correlation function, where the distances between the transmitting and receiving array elements are respectively... and ; The spatiotemporal correlation function of the birth and death characteristics of the scattering clusters of the LOS path is expressed as: in It is the link K factor. It is the direct path of link PQ. It is the direct path of link p'q. It is the Doppler frequency offset of the link pq. It is the Doppler frequency offset of link p'q; The spatiotemporal correlation function of the birth and death characteristics of scattering clusters along the NLOS path is expressed as: in, and They are and Probability density function.

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