Ray tracing channel modeling method for super-large-scale MIMO (Multiple Input Multiple Output) communication

Abstract

The invention discloses a ray tracing channel modeling method for super-large-scale MIMO (Multiple Input Multiple Output) communication. The method comprises the following steps: setting a simulation scene and simulation parameters for the super-large-scale MIMO communication, calculating a coherent distance of a super-large-scale MIMO antenna array, determining a selection interval of antenna units in the MIMO antenna array, and selecting the antenna units for simulation; performing ray tracing simulation on the selected antenna unit according to a reflection and diffraction propagation mechanism, determining a propagation trajectory of rays, determining ray paths in combination with a receiving end in a simulation scene, and screening out non-repeated ray paths from the ray paths; mapping the non-repeated ray paths to unselected antenna units in the MIMO antenna array, and determining ray paths of the unselected antenna units; and obtaining the channel characteristics of all antenna units in the MIMO antenna array, and realizing the construction of the ray tracing channel model of the super-large scale MIMO communication.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication technology, and particularly relates to a ray-tracing channel modeling method for ultra-large-scale MIMO communication. Background Art

[0002] In the design of 6G wireless communication networks, the demand for high-precision channel state information in deterministic networks and delay-sensitive networks is increasing day by day, which has promoted higher requirements for the accuracy of channel models. Ray-Tracing (RT) technology is based on the high-frequency approximation and the theory of uniform diffraction, and models the propagation of electromagnetic waves as ray propagation, so as to accurately predict the propagation characteristics of wireless signals. Compared with statistical channel modeling methods, ray tracing, as a deterministic channel modeling method, uses specific propagation environment information to obtain accurate channel characteristics in the time, frequency, and space domains by calculating the amplitude, delay, departure angle, and arrival angle of each multipath signal.

[0003] According to different implementation methods, ray-tracing methods are mainly divided into the Shooting and Bouncing Ray Method (SBR) and the Image Method (IM). The SBR has a relatively fast simulation speed but relatively low accuracy; while the IM can provide higher accuracy due to the use of accurate geometric optics calculations, but the simulation speed is slow. In a complex environment, the computational complexity of the IM increases exponentially with the increase in the number of objects in the scene, so it is not suitable for complex scenes with large-scale and dense object distributions. In contrast, the SBR has been more widely used in relatively complex communication environments because it can uniformly emit a large number of rays at the transmitter and trace their propagation paths in the scene. The SBR determines the rays reaching the receiver and calculates their propagation paths, thereby accurately obtaining multipath information and deriving accurate channel characteristics based on parameters such as the power, delay, and angle of the multipath signals.

[0004] Ultra-massive MIMO (Massive MIMO) communication is one of the important application scenarios in the 6G era. Its channel exhibits characteristics such as spherical wave characteristics, spatial non-stationarity, channel hardening effect, and angular domain sparsity. With the significant increase in the complexity of 6G systems, various channel characteristics may have a profound impact on system performance. Therefore, the ray-tracing-based channel model needs to comprehensively analyze relevant characteristics. However, in the ultra-massive MIMO scenario, due to the substantial increase in the number of antenna elements, the computational complexity of traditional ray-tracing models increases exponentially, resulting in a significant extension of the simulation time. Between simulation accuracy and computational complexity, the ray-tracing method faces a trade-off problem that is difficult to balance, making it difficult to efficiently obtain high-precision channel characteristics in the ultra-massive MIMO communication scenario. Therefore, the existing ray-tracing technologies have obvious limitations between computational efficiency and accuracy and urgently need to be improved to meet the channel modeling requirements of ultra-massive MIMO communication. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a ray-tracing channel modeling method for ultra-massive MIMO communication, which selects some antenna elements for simulation based on the coherence distance and uses a mapping method to determine the ray paths of the unselected antenna elements. The present invention can greatly simplify the ray-tracing simulation of ultra-massive MIMO antenna arrays, improve the simulation efficiency, and meet the channel modeling requirements of ultra-massive MIMO communication scenarios.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solutions: A ray-tracing channel modeling method for ultra-massive MIMO communication, comprising the following steps: Step S1: Set the simulation scenario and simulation parameters for ultra-massive MIMO communication, and calculate the coherence distance of the ultra-massive MIMO antenna array; Step S2: Determine the selection interval of antenna elements in the MIMO antenna array based on the coherence distance; Step S3: Select the antenna elements for simulation in the MIMO antenna array according to the selection interval; Step S4: Perform ray-tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms, determine the propagation trajectory of the rays, determine the ray paths in combination with the receiving end in the simulation scenario, and screen out non-repeated ray paths from the ray paths; Step S5: Map the non-repeated ray paths to the unselected antenna elements in the MIMO antenna array to determine the ray paths of the unselected antenna elements; Step S6: Obtain the channel characteristics of all antenna elements in the MIMO antenna array to realize the construction of the ray-tracing channel model for ultra-massive MIMO communication.

[0007] Further, setting up the simulation scenario and simulation parameters for ultra-large-scale MIMO antenna array communication includes: Taking the three-dimensional geometric model of buildings and objects composed of triangular faces as the simulation scenario, setting the positions of the transmitter and the receiver within the simulation scenario, and deploying an ultra-large-scale MIMO antenna array at the position of the transmitter, and setting the information of the ultra-large-scale MIMO antenna array, including: the arrangement mode of the ultra-large-scale MIMO antenna array, the number of antenna elements, and the antenna element spacing; The simulation scenario also includes several reflecting surfaces that reflect the rays emitted by the antenna elements and several wedges that diffract the rays emitted by the antenna elements; and setting the upper limits of the reflection order and diffraction order of the rays.

[0008] Further, the coherence distance of the ultra-large-scale MIMO antenna array The calculation process is as follows:

[0009] Wherein, is the autocorrelation function of the ultra-large-scale MIMO antenna array.

[0010] Further, the selection interval of the antenna elements in the MIMO antenna array The determination process is as follows:

[0011] Wherein, represents the spacing between adjacent antenna elements in the MIMO antenna array, represents rounding down.

[0012] Further, the specific process of step S3 is as follows: For an ultra-large-scale MIMO antenna array including rows and columns of antenna elements, select antenna elements along a straight line in the ultra-large-scale MIMO antenna array according to the selection interval of the antenna elements. The selected antenna elements are represented as:

[0013]

[0014] …

[0015] Wherein, n represents the selection interval of the antenna elements, , .

[0016] Further, the specific process of determining the ray path by performing ray tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms is as follows: i. Taking the position of each selected antenna element in the simulation scenario as the transmitting end, emit rays around it, and record both the reflection order and the diffraction order of the rays as zero; ii. For each ray, when the ray collides with a reflecting surface, generate a reflected ray according to the principle of mirror reflection and increment the reflection order by one; when the ray collides with an edge, generate a diffracted ray according to the principle of consistent diffraction and increment the diffraction order by one; iii. Repeat step ii for the reflected rays and the diffracted rays until the reflection order is equal to the set upper limit of the reflection order or the diffraction order is equal to the set upper limit of the diffraction order. Then stop propagating the rays and record the propagation trajectory of the rays; iv. Screen out the propagation trajectories that can reach the receiver position from the propagation trajectories of all the rays as the ray paths.

[0017] Further, the process of screening out non-redundant ray paths is as follows: For all the ray paths, judge in turn whether the order of the objects contacted during the propagation of the ray paths is exactly the same for every two ray paths. If they are the same, delete any one of the ray paths; otherwise, keep both ray paths.

[0018] Further, step S5 includes the following sub-steps: Step S5.1: For each non-redundant ray path, record all the reflecting surfaces and occluding surfaces on the ray path, where the occluding surfaces are all the object surfaces located between adjacent reflecting surfaces; Step S5.2: For each unselected antenna element in the MIMO antenna array, recalculate according to the principle of mirror reflection and the principle of consistent diffraction to determine all the ray propagation trajectories of the unselected antenna element; Step S5.3: Obtain the intersection points of each ray propagation trajectory of the unselected antenna element with all the reflecting surfaces on each non-redundant ray path and the intersection points with all the occluding surfaces on each non-redundant ray path; Step S5.4: For each non-redundant ray path, if the intersection points of the ray propagation trajectory with all the reflecting surfaces on the non-redundant ray path are all within the corresponding reflecting surfaces and the intersection points with all the occluding surfaces on the non-redundant ray path are all outside the corresponding occluding surfaces, then take the ray propagation trajectory as the ray path of the unselected antenna element.

[0019] Further, step S6 includes the following sub-steps: Step S6.1: Calculate the delay and angle information of each ray path according to all the ray paths of each antenna element in the MIMO antenna array; Step S6.2: Calculate the electric field at the receiving end of the simulation scenario based on all the ray paths of each antenna element in the MIMO antenna array, and determine the received power of the antenna element. Step S6.3: Use the time delay, angle information, and received power corresponding to all the antenna elements in the MIMO antenna array as the channel characteristics of the very large-scale MIMO communication scenario, and realize the construction of the ray tracing channel model for very large-scale MIMO communication.

[0020] Further, the electric field at the receiving end of the simulation scenario of the antenna element is obtained by accumulating the electric fields of all the ray paths of the antenna element at the receiving end of the simulation scenario. Among them, the calculation process of the electric field of each ray path at the receiving end of the simulation scenario is as follows:

[0021] Among them, is the electric field of a certain ray path of the antenna element at the receiving end of the simulation scenario, is the electric field of the transmitted ray corresponding to the ray path, is the total number of reflections, is the th reflection coefficient matrix of the ray in the ray path, is the wave number, is the propagation distance of the ray path, is the imaginary unit.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The ray tracing channel modeling method for very large-scale MIMO communication of the present invention is aimed at a very large-scale MIMO antenna array. Based on the coherence distance, some antenna elements are selected for ray tracing simulation, and other antenna elements are ignored, which can greatly simplify the ray tracing simulation steps and improve the simulation efficiency. In addition, for the unselected antenna elements, by using the intersection relationship between the ray propagation trajectories of the unselected antenna elements and all the reflection surfaces and occlusion surfaces of the non-repeated ray paths of the selected antenna elements, the ray paths of the unselected antenna elements are determined, and the ray paths of the selected antenna elements are accurately mapped to the unselected antenna elements, so as to ensure the rationality and accuracy of the acquisition of the ray paths of the unselected antenna elements, and ensure the simulation accuracy of ray tracing in the very large-scale MIMO communication scenario. The present invention can construct a ray tracing channel model for the very large-scale MIMO communication scenario, and can obtain accurate channel characteristics with extremely low simulation complexity, meeting the channel modeling requirements of the very large-scale MIMO communication scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flowchart of the ray tracing channel modeling method for very large-scale MIMO communication of the present invention; Figure 2 It is a schematic diagram of a simulation scenario; Figure 3 It is the received power coverage map of the MIMO antenna array using the ray tracing channel modeling method for ultra-large-scale MIMO communication of the present invention; Figure 4 It is the azimuth angle power spectrum result map of the MIMO antenna array using the ray tracing channel modeling method for ultra-large-scale MIMO communication of the present invention; Figure 5 It is the elevation angle power spectrum result map of the MIMO antenna array using the ray tracing channel modeling method for ultra-large-scale MIMO communication of the present invention. Detailed implementation manners

[0024] The technical solutions of the present invention will be further explained below with reference to the accompanying drawings.

[0025] As Figure 1 It is the flow chart of the ray tracing channel modeling method for ultra-large-scale MIMO communication of the present invention. This ray tracing channel modeling method includes the following steps: Step S1: Set the simulation scenario and simulation parameters for ultra-large-scale MIMO communication, including: Use the three-dimensional geometric model of buildings and objects composed of triangular faces as the simulation scenario. Set the receiving end in the simulation scenario, deploy the ultra-large-scale MIMO antenna array, use the ultra-large-scale MIMO antenna array as the transmitting end, record the positions of each antenna element in the ultra-large-scale MIMO antenna array and the position of the receiving end, and set the information of the ultra-large-scale MIMO antenna array, including: the arrangement mode of the ultra-large-scale MIMO antenna array, the number of antenna elements, and the antenna element spacing; The simulation scenario also includes several reflecting surfaces that reflect the rays emitted by the antenna elements and several wedges that diffract the rays emitted by the antenna elements; and set the upper limits of the reflection order and diffraction order of the rays. The upper limits of the reflection order and diffraction order respectively determine the upper limits of the number of reflections and diffractions of the rays during propagation.

[0026] Calculate the coherence distance of the ultra-large-scale MIMO antenna array according to the information of the simulation scenario and the MIMO antenna array:

[0027] Among them, is the autocorrelation function of the ultra-large-scale MIMO antenna array.

[0028] Step S2: When the antenna element spacing is less than the coherence distance, the ray path similarity of the antenna elements is high and there is no need for repeated simulation. Therefore, based on the coherence distance, the selection interval of the antenna elements in the MIMO antenna array is determined to select some antenna elements with large ray path differences for simulation, which can greatly reduce the simulation complexity.

[0029] The selection interval of the antenna elements in the MIMO antenna array in the present invention The calculation process is as follows:

[0030] Wherein, represents the spacing between adjacent antenna elements in the MIMO antenna array, represents rounding down.

[0031] Step S3: Select the antenna elements for simulation in the MIMO antenna array according to the selection interval; specifically, for the very large-scale MIMO antenna array including rows, columns of antenna elements, select the antenna elements along a straight line in the very large-scale MIMO antenna array according to the selection interval of the antenna elements. The selected antenna elements are represented as:

[0032]

[0033] …

[0034] Wherein, n represents the selection interval of the antenna elements, , .

[0035] Step S4: Perform ray tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms to determine the propagation trajectory of the rays, and combine the receiving end in the simulation scenario to determine the ray paths. Only select some antenna elements for ray tracing simulation, which can greatly simplify the ray tracing simulation steps and improve the simulation efficiency. In addition, the repeated ray paths contain redundant information, which will lead to a decrease in the subsequent simulation efficiency. Therefore, it is necessary to screen out the non-repeated ray paths from the ray paths, including the following sub-steps: Step S4.1: Take the position of each selected antenna element in the simulation scenario as the transmitter and emit rays around it. The directions of these rays are uniformly distributed on the unit sphere surrounding the transmitter, and both the reflection order and the diffraction order of the rays are recorded as zero; Step S4.2: For each ray, when the ray collides with the reflecting surface, generate a reflected ray according to the principle of mirror reflection and increment the reflection order by one; when the ray collides with the wedge, generate a diffracted ray according to the principle of uniform diffraction and increment the diffraction order by one; Step S4.3: Repeat Step S4.2 for the reflected rays and the diffracted rays until the reflection order reaches the set upper limit of the reflection order or the diffraction order reaches the set upper limit of the diffraction order. Then stop propagating the rays and record the propagation trajectories of the rays; Step S4.4: Screen out the propagation trajectories that can reach the receiver position from the propagation trajectories of all the rays as the ray paths; Step S4.5: For all the ray paths, pairwise determine whether the order of the objects contacted during the propagation of the ray paths is exactly the same. If they are the same, it means the two ray paths are duplicates, and delete any one of the ray paths; otherwise, it means the two ray paths are different, and both ray paths are retained.

[0036] Step S5: Map the non-duplicate ray paths to the unselected antenna elements in the MIMO antenna array to determine the ray paths of the unselected antenna elements, which can accurately obtain the ray paths of all antenna elements and ensure the accuracy of the channel characteristics obtained by simulation. It includes the following sub-steps: Step S5.1: For each non-duplicate ray path, record all the reflecting surfaces and occluding surfaces on the ray path, where the occluding surfaces are all the object surfaces located between adjacent reflecting surfaces; Step S5.2: For each unselected antenna element in the MIMO antenna array, recalculate according to the principle of mirror reflection and the principle of uniform diffraction, and there is no need to perform collision judgment again, so that the propagation trajectories of all rays of the unselected antenna elements can be quickly determined; Step S5.3: Obtain the intersection points of each ray propagation trajectory of the unselected antenna element with all the reflecting surfaces on each non-duplicate ray path and the intersection points with all the occluding surfaces on each non-duplicate ray path; Step S5.4: For each non-duplicate ray path, if the intersection points of the ray propagation trajectory with all the reflecting surfaces on the non-duplicate ray path are all within the corresponding reflecting surfaces and the intersection points with all the occluding surfaces on the non-duplicate ray path are all outside the corresponding occluding surfaces, then take the ray propagation trajectory as the ray path of the unselected antenna element. The reflecting surfaces and occluding surfaces are the objects in the simulation scenario that may affect the ray propagation trajectory. By selecting the reflecting surfaces and occluding surfaces instead of all the objects in the scenario to calculate the ray propagation trajectory, the determination accuracy can be guaranteed while the determination can be completed quickly.

[0037] For the unselected antenna elements, based on the intersection relationships between their ray propagation trajectories and all the reflecting and blocking surfaces of the non-repeated ray paths of the selected antenna elements, determine the ray paths of the unselected antenna elements, and accurately map the ray paths of the selected antenna elements to the unselected antenna elements, thereby ensuring the rationality and accuracy of obtaining the ray paths of the unselected antenna elements and guaranteeing the simulation accuracy of ray tracing in the very large-scale MIMO communication scenario.

[0038] Step S6: Obtain the channel characteristics of all antenna elements in the MIMO antenna array to construct a ray tracing channel model for very large-scale MIMO communication, including the following sub-steps: Step S6.1: Calculate the delay and angle information of each ray path according to all the ray paths of each antenna element in the MIMO antenna array:

[0039]

[0040]

[0041] Among them, is the delay of the ray path, is the total length of the ray path, is the speed of light, with a value of 299792458 m / s; is the azimuth angle at which the ray path exits, is the elevation angle at which the ray path exits, is the unit vector in the emission direction corresponding to the ray path; Step S6.2: Calculate the electric field at the receiving end of the simulation scenario according to all the ray paths of each antenna element in the MIMO antenna array to determine the receiving power of the antenna element; among them, the electric field of the antenna element at the receiving end of the simulation scenario is obtained by accumulating the electric fields of all the ray paths of the antenna element at the receiving end of the simulation scenario. The calculation process of the electric field of each ray path at the receiving end of the simulation scenario is as follows:

[0042] Among them, is the electric field of a certain ray path of the antenna element at the receiving end of the simulation scenario, is the electric field of the emission ray corresponding to the ray path, is the total number of reflections, is the th reflection coefficient matrix of the ray in the ray path, is the wave number, which can be calculated from the simulation frequency, , represents the set simulation frequency; is the propagation distance of the ray path, is the imaginary unit.

[0043] Step S6.3: Use the time delay, angle information, and received power corresponding to all antenna elements in the MIMO antenna array as the channel characteristics of the very large-scale MIMO communication scenario, and implement the construction of the ray-tracing channel model for very large-scale MIMO communication.

[0044] The ray-tracing channel modeling method for very large-scale MIMO communication according to the present invention can construct a ray-tracing channel model for a very large-scale MIMO communication scenario, obtain accurate channel characteristics with extremely low simulation complexity, and meet the channel modeling requirements of a very large-scale MIMO communication scenario.

[0045] Embodiment Take the urban scenario simulation as Figure 2 an example. Set the transmitter position and the receiver range, set the simulation frequency to 5.3 GHz, use a very large-scale MIMO antenna array as the transmitter, and set the size of the very large-scale MIMO antenna array to , which contains a total of 1024 antenna elements. The antenna element spacing is 0.0339 m, and the upper limit of the reflection order of the antenna element is set to 5, that is, the ray propagates in the scenario and experiences at most 5 reflections.

[0046] According to the simulation scenario, the coherence distance is obtained as 0.1 m, and then the antenna selection interval is calculated, that is, 1 out of every 4 antenna elements is selected for simulation; according to the antenna selection interval, a total of 64 antenna elements are selected, and the rows and columns where the selected antenna elements are located are represented as:

[0047]

[0048] Perform ray-tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms, determine the propagation trajectory of the rays, determine the ray paths in combination with the receivers in the simulation scenario, and screen out non-repeated ray paths from the ray paths; Map the non-repeated ray paths to the antenna elements in the MIMO antenna array that are not selected, and determine the ray paths of the antenna elements that are not selected; Obtain the channel characteristics of all antenna elements in the MIMO antenna array, and implement the construction of the ray-tracing channel model for very large-scale MIMO communication.

[0049] Figure 3The figure shows the simulation result of the received power of the MIMO antenna array in this embodiment, presenting the power coverage in the urban outdoor simulation scenario. It can be seen that the power coverage intensity of the receiving end close to the transmitting end is high, while that of the receiving end far away is low. The receiving end located at the back of the building, such as the dark blue area in the upper left corner of the figure, has a very low power coverage intensity due to being blocked. Compared with the traditional ray tracing method, the power coverage error obtained by simulating the ray tracing channel modeling method of the present invention is small, and the average error is less than 5 dB. Figure 4 The figure shows the result of the angle power spectrum of the arrival azimuth angle of the MIMO antenna array in this embodiment. Among them, red represents the angle power of the arrival azimuth angle with high received power, and blue represents the angle power of the arrival azimuth angle with low received power. It can be seen that the angle power of the arrival azimuth angle shows periodic fluctuations along the antenna index, indicating that the ray path angles generated by different antenna elements are different. This is a characteristic presented under the condition of spherical wave propagation, thereby reflecting the spherical wave characteristic of the very large-scale MIMO channel, indicating that the ray tracing channel modeling method of the present invention can support the very large-scale MIMO communication scenario. Figure 5 The figure shows the result of the angle power spectrum of the arrival elevation angle of the MIMO antenna array in this embodiment. Among them, red represents the angle power of the arrival elevation angle with high received power, and blue represents the angle power of the arrival elevation angle with low received power. It can be seen that the angle power of the arrival elevation angle shows a birth-death effect along the antenna index, which indicates that the ray paths corresponding to some antenna elements are blocked, reflecting the spatial non-stationary characteristic of the very large-scale MIMO channel, indicating that the present invention can support the very large-scale MIMO communication scenario.

[0050] In a technical solution of the present invention, a computer-readable storage medium is further provided, storing a computer program, and the computer program enables a computer to execute a ray tracing channel modeling method for very large-scale MIMO communication.

[0051] In a technical solution of the present invention, an electronic device is further provided, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, a ray tracing channel modeling method for very large-scale MIMO communication is implemented.

[0052] In the embodiments disclosed in the present application, the computer storage medium may be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of the computer storage medium would include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0053] Those of ordinary skill in the art will appreciate that the units and algorithm steps of the examples described in connection with the embodiments disclosed in the present application can be implemented in electronic hardware or in a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present application.

[0054] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art of this technology, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A ray-tracing channel modeling method for ultra-large-scale MIMO communication, characterized in that It includes the following steps: Step S1: Set the simulation scenario and simulation parameters for very large-scale MIMO communication, and calculate the coherence distance of the MIMO antenna array; Step S2: Determine the selection interval of antenna elements in the MIMO antenna array based on the coherence distance; Step S3: Select the antenna elements for simulation in the MIMO antenna array according to the selection interval; Step S4: Perform ray tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms, determine the propagation trajectory of the rays, combine with the receiving end in the simulation scenario to determine the ray paths, and screen out non-repeated ray paths from the ray paths; Step S5: Map the non-repeated ray paths to the unselected antenna elements in the MIMO antenna array to determine the ray paths of the unselected antenna elements; Step S6: Obtain the channel characteristics of all antenna elements in the MIMO antenna array to realize the construction of the ray tracing channel model for very large-scale MIMO communication.

2. The ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that Setting the simulation scenario and simulation parameters for very large-scale MIMO antenna array communication includes: Taking the three-dimensional geometric model of buildings and objects composed of triangular faces as the simulation scenario, setting the positions of the transmitter and the receiver in the simulation scenario, and deploying a very large-scale MIMO antenna array at the transmitter position, and setting the information of the very large-scale MIMO antenna array, including: the arrangement mode of the very large-scale MIMO antenna array, the number of antenna elements and the antenna element interval; The simulation scenario also includes several reflecting surfaces that reflect the rays emitted by the antenna elements and several wedges that diffract the rays emitted by the antenna elements; and set the upper limit of the reflection order and diffraction order of the rays.

3. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that Coherence distance of the very large scale MIMO antenna array The calculation process is as follows: Among them, is the autocorrelation function of the very large scale MIMO antenna array.

4. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 3, characterized in that The selection interval of antenna elements in the MIMO antenna array is determined as follows: Among them, represents the spacing between adjacent antenna elements in the MIMO antenna array, represents rounding down.

5. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that The specific process of step S3 is as follows: For a very large-scale MIMO antenna array including rows, and columns of antenna elements, antenna elements are selected along a straight line in the very large-scale MIMO antenna array according to the selection interval of the antenna elements. The selected antenna elements are represented as: … Among them, n represents the selection interval of the antenna elements, , .

6. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that The specific process of performing ray tracing simulation on the selected antenna elements according to the reflection and diffraction propagation mechanisms to determine the ray paths is: i. Taking the position of each selected antenna element in the simulation scenario as the transmitter, emitting rays around, and recording both the reflection order and diffraction order of the rays as zero; ii. For each ray, when the ray collides with a reflecting surface, generate a reflected ray according to the principle of mirror reflection, and increment the reflection order by one; when the ray collides with a wedge, generate a diffracted ray according to the principle of consistent diffraction, and increment the diffraction order by one; iii. Repeat step ii for the reflected rays and diffracted rays until the reflection order is equal to the set upper limit of the reflection order or the diffraction order is equal to the set upper limit of the diffraction order, then stop propagating the rays and record the propagation trajectory of the rays; iv. Screen out the propagation trajectories that can reach the receiver position from the propagation trajectories of all rays as the ray paths.

7. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 6, characterized in that The process of screening out non-repeated ray paths is: For all ray paths, judge in turn whether the order of the objects contacted during the propagation of the ray paths is exactly the same. If they are the same, delete any one of the ray paths; Otherwise, both ray paths are retained.

8. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that, Step S5 includes the following sub-steps: Step S5.1: For each non-repeated ray path, record all the reflecting surfaces and occluding surfaces on the ray path, where the occluding surfaces are all object surfaces located between adjacent reflecting surfaces; Step S5.2: For each unselected antenna element in the MIMO antenna array, recalculate according to the mirror principle and the uniform theory of diffraction to determine all ray propagation trajectories of the unselected antenna element; Step S5.3: Obtain the intersections of each ray propagation trajectory of the unselected antenna element with all reflecting surfaces on each non-repeated ray path and the intersections with all occluding surfaces on each non-repeated ray path; Step S5.4: For each non-repeated ray path, if the intersections of the ray propagation trajectory with all reflecting surfaces on the non-repeated ray path are all within the corresponding reflecting surfaces, and the intersections with all occluding surfaces on the non-repeated ray path are all outside the corresponding occluding surfaces, then take the ray propagation trajectory as the ray path of the unselected antenna element.

9. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 1, characterized in that Step S6 includes the following sub-steps: Step S6.1: Calculate the time delay and angle information of each ray path according to all ray paths of each antenna element in the MIMO antenna array; Step S6.2: Calculate the electric field at the receiving end of the simulation scenario according to all ray paths of each antenna element in the MIMO antenna array to determine the received power of the antenna element; Step S6.3: Take the time delay, angle information, and received power corresponding to all antenna elements in the MIMO antenna array as the channel characteristics of the very large scale MIMO communication scenario, and realize the construction of the ray tracing channel model for very large scale MIMO communication.

10. A ray tracing channel modeling method for ultra-large scale MIMO communication according to claim 9, characterized in that, The electric field of the antenna element at the receiving end of the simulation scenario is obtained by accumulating the electric fields of all ray paths of the antenna element at the receiving end of the simulation scenario. Among them, the calculation process of the electric field of each ray path at the receiving end of the simulation scenario is as follows: Wherein, is the electric field at the receiving end of a certain ray path in the antenna unit in the simulation scenario, is the electric field of the transmitting ray corresponding to the ray path, is the total number of reflections, is the th reflection coefficient matrix of the ray in the ray path, is the wave number, is the propagation distance of the ray path, is the imaginary unit.

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