Wireless communication power coverage calculation method based on ray tracing

Abstract

The invention discloses a wireless communication power coverage calculation method based on ray tracing, which solves the problem of low simulation efficiency of a ray tracing technology in a scene with a large number of receiving points, and comprises the following steps of: 1) preprocessing a wireless channel environment, and combining the surfaces of objects in the scene into a polygon; 2) transmitting an initial projection ray beam according to the position of the transmitting end; (3) intersection judgment is conducted on the projection ray beams, and new propagation ray beams and projection ray beams are generated; 4) receiving judgment is carried out on the propagation ray beam, and a receiving point covered by the propagation ray beam is calculated; and 5) calculating accurate channel information according to the receiving points covered by the propagation ray beams. According to the invention, the simulation efficiency of the power coverage calculation of the ray tracing algorithm is improved, and the simulation precision is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a wireless communication power coverage calculation method based on ray tracing. Background Art

[0002] Deterministic networks and delay-sensitive networks in the design of 6G wireless communication networks have a great demand for high-precision channel state information, which drives a higher demand for channel model accuracy. Ray-Tracing (RT) technology models the propagation process of electromagnetic waves as the propagation of rays through high-frequency approximation and consistent diffraction theory, which can accurately predict the propagation results of wireless signals. Compared with the statistical channel modeling method, the ray tracing deterministic channel modeling method uses specific propagation environment information to calculate the amplitude, delay, departure angle and arrival angle of each multipath signal component, and can obtain the accurate channel characteristics of different scenario channels in time, frequency and space.

[0003] According to different implementation methods, ray tracing methods can be roughly divided into two types, Shooting and Bouncing Ray Method (SBR) and Image Method (IM). The ray bouncing method has a faster simulation speed but lower accuracy than the image method, while the image method has higher accuracy but slower simulation speed than the ray bouncing method. In complex scenes, the simulation time of the image method will increase exponentially according to the number of objects in the scene, so the image method is relatively unsuitable for urban scenes with large areas and many objects.

[0004] In relatively complex communication scenarios, the ray bouncing method is more widely used. The ray bouncing method evenly launches thousands of rays at the transmitter, and these rays propagate in the scene until the number of interactions such as reflection or diffraction reaches a preset order. By determining the rays that reach the receiver and calculating their ray paths, the multipath information of the transmitter and the receiver can be accurately calculated. Using the power, delay, angle and other information of these multipaths, accurate channel characteristics can be calculated.

[0005] With the development of communication technology, many communication scenarios have a great demand for high-precision channel state information. However, the existing ray tracing algorithm has a trade-off relationship between simulation speed and accuracy, and it is impossible to obtain high-precision channel characteristics of various 6G communication scenarios with high-efficiency simulation. If there are a large number of receiving points, the current ray tracing solution needs to perform reception judgment calculations at each receiving point, so the overall simulation time increases significantly. In more complex communication scenarios, neither the ray bouncing method nor the mirror method can achieve efficient acquisition of channel characteristics. Therefore, the existing ray tracing technology is difficult to meet the channel modeling needs of massive receiving points in complex communication scenarios in the future. Summary of the invention

[0006] Technical problem: When simulating wireless communication channels in scenarios with a large number of receiving points, the existing ray tracing technology has the problem of long operation time and low simulation efficiency. The present invention provides a wireless communication power coverage calculation method based on ray tracing. By designing projection ray beams and propagation ray beams, the present invention can achieve higher-precision ray tracing and greatly simplify the intersection determination steps at the receiving point end, greatly improving the simulation efficiency, and meeting the needs of wireless channel simulation in complex communication scenarios and a large number of receiving points in the future.

[0007] Technical solution, for a large number of receiving point channel simulation scenarios, the present invention proposes a wireless communication power coverage calculation method based on ray tracing, the method comprising the following steps:

[0008] Step S1, preprocessing the wireless channel environment, merging the surfaces of objects in the scene into polygons;

[0009] Step S2, emitting an initial projection ray beam according to the position of the emitting end;

[0010] Step S3, performing intersection determination on the projection ray beam to generate a new propagation ray beam and a projection ray beam;

[0011] Step S4, performing reception determination on the propagation ray beam, and calculating the reception points covered by the propagation ray beam;

[0012] Step S5: Calculate the multipath information of each receiving point based on the receiving points covered by the propagation beam, calculate the channel characteristics such as the receiving power based on the multipath information, and record the power of all receiving points to obtain the power coverage result.

[0013] Furthermore, the S1 step includes:

[0014] S1.1. Split all objects in the scene into reflective surfaces, and calculate the vertices, plane equations, and normal vectors of all reflective surfaces;

[0015] S1.2. Select all reflecting surfaces with the same plane equation and split them into line segments with directions, where each line segment represents an edge of the reflecting surface;

[0016] S1.3, starting from a split line segment, search for the next line segment according to its direction. If two line segments have the same vertices and opposite directions, eliminate the two line segments together; if two line segments connected in sequence have the same direction, merge the two line segments into one;

[0017] S1.4. Reassemble the remaining line segments into polygons and replace the original reflection surfaces with the same plane equations.

[0018] Furthermore, the S2 step includes:

[0019] S2.1. Find the plane closest to the transmitter and record its distance to the transmitter as d min ;

[0020] S2.2, the construction side length is 1.8×d min A cube with its center at the transmitting end is constructed with six faces of the cube as the base and the center of the cube as the vertex to form six tetrahedral pyramids;

[0021] S2.3. Use the six generated quadrangular pyramid vertices as the source points of the initial projection ray beam, and the bottom surface of the quadrangular pyramid as the bottom surface of the initial projection ray beam, to generate six initial projection ray beams.

[0022] Furthermore, the S3 step includes:

[0023] S3.1. Calculate the plane equation of the bottom surface of the projection ray beam, and project the reflection surface in the scene onto the plane where the bottom surface of the projection ray beam is located;

[0024] Furthermore, step S3.1 includes the following sub-steps:

[0025] S3.1.1. Substitute all vertices of the plane in the scene into the plane equation of the bottom surface of the projection ray beam, determine whether all vertices of the plane in the scene are on the same side of the bottom surface of the projection ray beam as the source point of the projection ray beam, and only retain the planes on the same side;

[0026] S3.1.2. Connect the vertices of the retained rear plane with the source point of the projection ray beam to form straight lines, calculate the intersection points of these straight lines with the bottom surface of the projection ray beam, and the polygon formed by the intersection points is the polygon after the reflection surface in the scene is projected;

[0027] S3.2, determining whether the projection reflection surface intersects with the bottom surface of the projection ray beam;

[0028] S3.3, dividing the bottom surface of the projection ray beam according to the projection reflection surface intersecting with the bottom surface of the projection ray beam, generating a plurality of polygons, and using these polygons to generate a propagation ray beam;

[0029] Furthermore, step S3.3 includes the following sub-steps:

[0030] S3.3.1. Calculate the distances from all intersecting reflection surfaces to the bottom of the projection ray beam, and sort the intersecting reflection surfaces in ascending order of distance;

[0031] S3.3.2. Segment the projection reflection surface from the bottom surface of the projection ray beam, cut the bottom surface of the projection ray beam into a number of polygons using all the edges of the projection reflection surface, and use the polygons generated after cutting to segment the subsequent projection reflection surfaces until all the projection reflection surfaces are segmented, at which time a number of cutting polygons are generated;

[0032] S3.3.3. Taking each cutting polygon as the top surface of a propagation ray beam and taking the reflection surface in the scene corresponding to each cutting polygon as the bottom surface of a propagation ray beam, generating a plurality of propagation ray beams;

[0033] S3.4. Generate a corresponding new projection ray beam according to each propagation ray beam.

[0034] Furthermore, step S3.4 includes the following sub-steps:

[0035] S3.4.1. Mirror the source point of the original projection ray beam about the plane where the bottom surface of each propagation ray beam is located to generate a number of corresponding mirror source points;

[0036] S3.4.2. Each mirror image source point is used as the source point of a new projection ray beam, and the bottom surface of the corresponding propagation ray beam is used as the bottom surface of the new projection ray beam to generate several new projection ray beams.

[0037] Furthermore, the S4 step includes:

[0038] S4.1, dividing the minimum bounding box according to the geometric size of the propagation ray beam, and screening out the receiving points contained in the bounding box;

[0039] Furthermore, step S4.1 includes the following sub-steps:

[0040] S4.1.1. Record all vertices on the top and bottom surfaces of the propagating ray beam, calculate the minimum and maximum x, y, and z coordinates of all vertices, and record them as: min ,x max ,y min ,y max ,z min ,z max ;

[0041] S4.1.2. Construct a minimum bounding box cube based on the six recorded coordinate values. The eight vertex coordinates of the cube are constructed as follows:

[0042] Box1=(x min ,y min ,z min ),Box2=(x min ,y max ,z min )

[0043] Box3=(x max ,y min ,z min ),Box4=(x max ,y max ,z min )

[0044] Box5=(x min ,y min ,z max ),Box6=(x min ,y max ,z max )

[0045] Box7=(x max ,y min ,z max ),Box8=(x max ,y max ,z max )

[0046] Among them, Box1 to Box8 are the coordinates of the eight vertices of the minimum bounding box;

[0047] S4.1.3, determine whether the coordinates of each receiving point are within the minimum bounding box cube, filter out the receiving points that do not meet the conditions, and retain the receiving points that meet the conditions;

[0048] S4.2. Perform secondary screening on the receiving points retained in step S4.1.3, exclude the receiving points located outside the top and bottom surfaces of the propagation ray beam, and exclude the receiving points located outside each edge surface of the propagation ray beam, to obtain all the receiving points located within the propagation ray beam.

[0049] Furthermore, the step S5 includes:

[0050] S5.1. For the receiving point in the ray beam, record the wall surface through which the corresponding ray beam is reflected. Calculate the ray path connecting the transmitting end and the receiving end according to the plane equation of these walls and the principle of mirror reflection. These ray paths are the multipath information between the transmitting and receiving ends.

[0051] S5.2. For each receiving point, calculate the electric field of all ray paths at the receiving point, and add up the electric field of each ray path to get the receiving power of this receiving point. The electric field of a single ray path is calculated as follows:

[0052]

[0053] Among them, E Rx is the electric field of a ray path at the receiving point, E Tx is the electric field of the corresponding emitted ray, R i is the reflection coefficient matrix of the i-th reflection, n is the total number of reflections, β is the wave number, and d is the propagation distance of the ray path.

[0054] S5.3. Record the receiving power of all receiving points to obtain the power coverage result.

[0055] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0056] The present invention designs projection ray beams and propagation ray beams based on the concept of projection. The projection ray beams efficiently complete the intersection judgment required for ray propagation. The propagation ray beams record the ray propagation range and realize fast reception judgment for a large number of receiving point scenarios, which greatly improves the simulation efficiency of ray tracing technology in a large number of receiving point scenarios and achieves higher simulation accuracy. Compared with the existing ray tracing algorithms, the present invention can obtain accurate channel information in a shorter simulation time and has extremely high simulation efficiency in a large number of receiving point scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 : Flow chart of the method of the present invention;

[0058] Figure 2 :Definition and propagation diagram of projection ray beam and propagation ray beam;

[0059] Figure 3 :10 5 The simulation receiving power result diagram of the present invention at each receiving point;

[0060] Figure 4 :10 5 The simulation receiving power error result diagram of the present invention at each receiving point;

[0061] Figure 5 :10 6 The simulation receiving power result diagram of the present invention at each receiving point;

[0062] Figure 6 :10 6 A top view of the simulation receiving power results of the present invention at each receiving point. DETAILED DESCRIPTION

[0063] Embodiment 1:

[0064] S1. Define a 800m×1100m urban scene communication area, divide the objects in the scene into line segments, and reassemble them into polygons. Define the transmitter height as 2m, and the two transmitters are located at the intersection and the center of the square respectively. The receiver height is 1.5m, and the number is up to 10 6 And evenly distributed in the scene;

[0065] S2, with the transmitting end as the center, generate 6 initial projection ray beams;

[0066] S3, perform intersection determination on the projection ray beam, and generate a new propagation ray beam and a projection ray beam. Figure 2As shown, the reflection surface 2 in the scene is projected onto the plane where the reflection surface 1 is located through the first mirror point of the transmitting end. There is an intersection area between the projected polygon and the projection ray beam 1, so a propagation ray beam will be generated. The top surface of the propagation ray beam 1 is the projected polygon, and the bottom surface is the reflection surface 2. Then, it is necessary to mirror the first mirror point of the transmitting end about the plane where the reflection surface 2 is located to generate the second mirror point of the transmitting end. Thus, the projection ray beam 2 is generated, whose source point is the second mirror point of the transmitting end, and the bottom surface is the reflection surface 2. These ray beams propagate in the scene to generate new projection ray beams and propagation ray beams until the reflection reaches 6 times;

[0067] S4, dividing the minimum bounding box based on the propagation ray beam, first screen out the receiving points outside the bounding box. Then use all surfaces of the propagation ray beam to make a judgment, and exclude the receiving points outside the propagation ray beam;

[0068] S5. Calculate the multipath information of each receiving point based on the receiving points covered by the propagation beam, calculate the channel characteristics such as the receiving power based on the multipath information, and record the power of all receiving points to obtain the power coverage result.

[0069] Figure 3 The improved ray tracing channel modeling method proposed in this invention is demonstrated. 5 The received power results of the receiving points are shown in Figure 2. Figure 4 The present invention and the traditional method are shown in 10 5 Compared with the traditional method, the error of the path loss result obtained by the simulation of the present invention is within 5dB, and the overall simulation error is small.

[0070] Figure 5 and Figure 6 The improved ray tracing channel modeling method proposed in this invention is demonstrated. 6 The received power result diagram of the receiving points verifies that the present invention can be used for urban scene simulation and obtain detailed and accurate power coverage results.

[0071] Table 1 shows the improvement of the present invention in terms of computational efficiency. When calculating power coverage, when the number of receiving points increases to the order of one hundred thousand or one million, the present invention can increase the simulation speed by at least 100 times.

[0072] Table 1: Comparison of simulation time consumption between the present invention and the traditional ray tracing method

[0073] Number of receiving points <![CDATA[10 3 ]]> <![CDATA[10 4 ]]> <![CDATA[10 5 ]]> <![CDATA[10 6 <!-- 4 -->]]> Traditional method simulation time (seconds) 137 1046 13009 110458 Simulation time of the method of the present invention (seconds) 53.34 56.97 58.03 110.34 The simulation time reduction of the present invention (%) 61.07 94.55 99.55 99.90

[0074] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A wireless communication power coverage calculation method based on ray tracing, characterized in that: The method comprises the following steps: Step S1, preprocessing the wireless channel environment, merging the surfaces of objects in the scene into polygons; Step S2, emitting an initial projection ray beam according to the position of the emitting end; Step S3, performing intersection determination on the projection ray beam to generate a new propagation ray beam and a projection ray beam; Step S4, performing reception determination on the propagation ray beam, and calculating the reception points covered by the propagation ray beam; Step S5: Calculate the multipath information of each receiving point according to the receiving points covered by the propagation beam, calculate the receiving power channel characteristics according to the multipath information, and record the power of all receiving points to obtain the power coverage result.

2. The wireless communication power coverage calculation method based on ray tracing according to claim 1, characterized in that: The S1 step includes: S1.

1. Split all objects in the scene into reflective surfaces, and calculate the vertices, plane equations, and normal vectors of all reflective surfaces; S1.

2. Select all reflecting surfaces with the same plane equation and split them into line segments with directions, where each line segment represents an edge of the reflecting surface; S1.3, starting from a split line segment, search for the next line segment according to its direction. If two line segments have the same vertices and opposite directions, eliminate the two line segments together; if two line segments connected in sequence have the same direction, merge the two line segments into one; S1.

4. Reassemble the remaining line segments into polygons and replace the original reflection surfaces with the same plane equations.

3. The wireless communication power coverage calculation method based on ray tracing according to claim 1, characterized in that: The S2 step includes: S2.

1. Find the plane closest to the transmitter and record its distance to the transmitter as d min ; S2.2, the construction side length is 1.8×d min A cube with its center at the transmitting end is constructed with six faces of the cube as the base and the center of the cube as the vertex to form six tetrahedral pyramids; S2.

3. Use the six generated quadrangular pyramid vertices as the source points of the initial projection ray beam, and the bottom surface of the quadrangular pyramid as the bottom surface of the initial projection ray beam, to generate six initial projection ray beams.

4. The wireless communication power coverage calculation method based on ray tracing according to claim 1, characterized in that: The S3 step includes: S3.1, calculating the plane equation of the bottom surface of the projection ray beam, and projecting the reflection surface in the scene to the plane where the bottom surface of the projection ray beam is located; step S3.1 includes the following sub-steps: S3.1.

1. Substitute all vertices of the plane in the scene into the plane equation of the bottom surface of the projection ray beam, determine whether all vertices of the plane in the scene are on the same side of the bottom surface of the projection ray beam as the source point of the projection ray beam, and only retain the planes on the same side; S3.1.

2. Connect the vertices of the retained rear plane with the source point of the projection ray beam to form straight lines, calculate the intersection points of these straight lines with the bottom surface of the projection ray beam, and the polygon formed by the intersection points is the polygon after the reflection surface in the scene is projected; S3.2, determining whether the projection reflection surface intersects with the bottom surface of the projection ray beam; S3.

3. The bottom surface of the projection ray beam is divided according to the projection reflection surface intersecting with the bottom surface of the projection ray beam to generate a plurality of polygons, and the propagation ray beam is generated using these polygons.

5. The wireless communication power coverage calculation method based on ray tracing according to claim 4, characterized in that: Step S3.3 includes the following sub-steps: S3.3.

1. Calculate the distances from all intersecting reflection surfaces to the bottom of the projection ray beam, and sort the intersecting reflection surfaces in ascending order of distance; S3.3.

2. Segment the projection reflection surface from the bottom surface of the projection ray beam, cut the bottom surface of the projection ray beam into a number of polygons using all the edges of the projection reflection surface, and use the polygons generated after cutting to segment the subsequent projection reflection surfaces until all the projection reflection surfaces are segmented, at which time a number of cutting polygons are generated; S3.3.

3. Taking each cutting polygon as the top surface of a propagation ray beam and taking the reflection surface in the scene corresponding to each cutting polygon as the bottom surface of a propagation ray beam, generating a plurality of propagation ray beams; S3.

4. Generate a corresponding new projection ray beam according to each propagation ray beam.

6. The wireless communication power coverage calculation method based on ray tracing according to claim 5, characterized in that: Step S3.4 includes the following sub-steps: S3.4.

1. Mirror the source point of the original projection ray beam about the plane where the bottom surface of each propagation ray beam is located to generate a number of corresponding mirror source points; S3.4.

2. Each mirror image source point is used as the source point of a new projection ray beam, and the bottom surface of the corresponding propagation ray beam is used as the bottom surface of the new projection ray beam to generate several new projection ray beams.

7. The wireless communication power coverage calculation method based on ray tracing according to claim 6, characterized in that: The S4 step includes: S4.1, dividing the minimum bounding box according to the geometric size of the propagation ray beam, and screening out the receiving points contained in the bounding box; step S4.1 includes the following sub-steps: S4.1.

1. Record all vertices on the top and bottom surfaces of the propagating ray beam, calculate the minimum and maximum x, y, and z coordinates of all vertices, and record them as: min ,x max ,y min ,y max ,z min ,z max ; S4.1.

2. Construct a minimum bounding box cube based on the six recorded coordinate values. The eight vertex coordinates of the cube are constructed as follows: Box1=(x min ,y min ,z min ),Box2=(x min ,y max ,z min ) Box3=(x max ,y min ,z min ),Box4=(x max ,y max ,z min ) Box5=(x min ,y min ,z max ),Box6=(x min ,y max ,z max ) Box7=(x max ,y min ,z max ),Box8=(x max ,y max ,z max ) Among them, Box1 to Box8 are the coordinates of the eight vertices of the minimum bounding box; S4.1.

3. Determine whether the coordinates of each receiving point are within the minimum bounding box cube, filter out the receiving points that do not meet the conditions, and retain the receiving points that meet the conditions; S4.

2. Perform secondary screening on the receiving points retained in step S4.1.3, exclude the receiving points located outside the top and bottom surfaces of the propagation ray beam, and exclude the receiving points located outside each edge surface of the propagation ray beam, to obtain all the receiving points located within the propagation ray beam.

8. The wireless communication power coverage calculation method based on ray tracing according to claim 7, characterized in that: The S5 step includes: S5.

1. For the receiving point in the ray beam, record the wall surface through which the corresponding ray beam is reflected, and calculate the ray path connecting the transmitting end and the receiving end according to the plane equation of the wall surface and the principle of mirror reflection. The ray path is the multipath information between the transmitting and receiving ends. S5.

2. For each receiving point, the electric field of all ray paths at the receiving point is calculated, and the electric field of each ray path is accumulated to obtain the receiving power of this receiving point. The electric field of a single ray path is calculated as follows: Among them, E Rx is the electric field of a ray path at the receiving point, E Tx is the electric field of the corresponding emitted ray, R i is the reflection coefficient matrix of the i-th reflection, n is the total number of reflections, β is the wave number, and d is the propagation distance of the ray path; S5.

3. Record the receiving power of all receiving points to obtain the power coverage result.

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