A path loss modeling method for RIS-assisted communication system

Abstract

This invention discloses a path loss modeling method for RIS-assisted communication systems, comprising: establishing a three-dimensional coordinate system with the RIS center as the coordinate center, and constructing a path loss model dataset; setting the adjustment step size to s, and dividing the RIS electromagnetic unit into regularly sized RIS electromagnetic blocks; constructing a joint normalized power radiation pattern of the transmitting antenna, RIS electromagnetic blocks, and receiving antenna; constructing the total phase change term of the signal after reflection by the RIS electromagnetic blocks; constructing the programmable reflection coefficient of the RIS electromagnetic unit; constructing a double-superposition reflection gain model of the RIS electromagnetic unit performance; and integrating these to obtain the final path loss model method. This invention achieves a unified theoretical framework for propagation characteristics from near field to far field, significantly improves computational efficiency, and can be dynamically adjusted according to actual scenario requirements, achieving a dynamic balance between computational efficiency and system performance, providing engineering support for RIS to achieve low-latency, deployable systems in real dynamic environments.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically to a path loss modeling method for RIS-assisted communication systems. Background Technology

[0002] Path loss models are core tools for describing signal power attenuation during propagation, and are crucial for link budgeting, performance analysis, and network deployment in communication systems. RIS (Reconfigurable Intelligent Surface)-assisted communication systems exhibit path loss characteristics fundamentally different from traditional point-to-point communication due to the cascaded channel structure (transmitter-RIS-receiver) introduced by RIS. The array gain, element scattering characteristics, phase configuration strategy, and operating region (near-field / far-field) of the RIS all have complex effects on path loss.

[0003] Currently, most studies have explored path loss models for RIS-assisted communication systems in a fragmented manner, failing to establish a unified framework. This leads to decreased prediction accuracy in the near-field boundary region, resulting in inaccurate performance evaluation of the communication system. Furthermore, the fragmented models increase the complexity of parameter estimation, requiring separate calibration for different scenarios, which is inefficient and difficult to adapt to dynamic environments.

[0004] Secondly, the existing path loss model of RIS-assisted communication system is highly complex, and the computational overhead increases exponentially with the increase of the number of RIS units, making it difficult to meet the real-time optimization requirements of large-scale RIS-assisted communication systems and unable to be effectively applied to real-world scenarios that require real-time beamforming or dynamic channel estimation.

[0005] In addition, existing models are relatively rigid, making it difficult to precisely control and flexibly balance model complexity, computational efficiency and prediction accuracy. They lack effective adjustment mechanisms, cannot be dynamically adjusted according to the needs of actual scenarios, and are difficult to achieve a dynamic balance between computational efficiency and system performance. They have poor adaptability, either having excessive computational overhead or insufficient accuracy. For example, the free space path loss modeling method proposed in the paper "Wireless communications with reconfigurable intelligent surface: Path loss modeling and experimental measurement" published in IEEE Transactions on Wireless Communications reveals the relationship between the free space path loss of the RIS and the distance from the transmitter / receiver to the RIS, the size of the RIS, the near-field / far-field effect of the RIS, and the radiation pattern of the antenna and the unit. It proposes to consider key physical characteristics such as the physical size of the RIS and the radiation pattern of the unit, and derives a general formula to characterize the free space path loss of RIS-assisted wireless communication. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a path loss modeling method for RIS-assisted communication systems. This method realizes a unified theoretical framework for propagation characteristics from the near field to the far field, significantly improves computational efficiency, and can be dynamically adjusted according to actual scenario requirements to achieve a dynamic balance between computational efficiency and system performance.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a path loss modeling method for RIS-assisted communication systems, comprising: S1. Establish a three-dimensional coordinate system with the RIS center as the coordinate center, and construct the path loss model dataset. ; S2, Set the adjustment step size to , ,Bundle Each RIS electromagnetic unit is divided into sizes. Regular electromagnetic blocks of electromagnetic units; Among them, the adjustment step size It can be dynamically adjusted according to the real-time requirements of specific application scenarios; S3. Construct the joint normalized power radiation pattern of the transmitting antenna, RIS electromagnetic block, and receiving antenna. Specifically, calculate the power radiation pattern of the transmitting antenna, the RIS electromagnetic block, and the receiving antenna, then multiply all the patterns to obtain the joint normalized power radiation pattern. ; S4. Construct the total phase change term of the signal after reflection by the RIS electromagnetic block, based on the path loss model dataset. Combined with wavelength Construct a dynamic estimation function for the total phase change. ; S5. Construct the programmable reflection coefficient of the RIS electromagnetic unit, including the reflection amplitude of the RIS electromagnetic unit. Compensation phase angle of RIS electromagnetic unit Using the core variable, a dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed. ; S6. Based on the aforementioned joint normalized power radiation pattern Dynamic estimation function of total phase change and the dynamic estimation function of programmable reflection coefficient Based on the total number of RIS electromagnetic blocks, a dual superposition reflection gain model of RIS electromagnetic unit performance is constructed. ; S7, introduces RIS with long physical size and Total number of electromagnetic units Transmit antenna gain Receiver antenna gain The dual superposition reflection gain model of the RIS electromagnetic unit performance is incorporated. The final path loss is obtained by integration. .

[0008] The present invention further illustrates that the path loss model dataset in S1 This includes the distance from the transmitting antenna to the RIS center. Distance from receiving antenna to RIS center Distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Coordinates of the transmitting antenna Coordinates of the receiving antenna Coordinates of the RIS electromagnetic unit Coordinates of the RIS electromagnetic block Transmit antenna gain Receiver antenna gain .

[0009] The present invention further explains that the control step size in S2 The dynamic adjustment method includes: determining the real-time level based on the real-time requirements of the specific application scenario, and adjusting the control step size according to the determined real-time level. ; Based on the aforementioned control step size Determine the total number of RIS electromagnetic blocks × ,in At the same time, a block mapping model for RIS electromagnetic units and RIS electromagnetic blocks is established.

[0010] The present invention further explains that the calculation of the joint normalized power radiation pattern in S3 specifically involves: Based on the path loss model dataset in S1 The distance from the transmitting antenna to the center of the RIS Distance from the transmitting antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Transmit antenna gain The power radiation pattern of the transmitting antenna is calculated using the following formula, where is the variable: ; Based on the path loss model dataset in S1 The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block Coordinates of the transmitting antenna Coordinates of the receiving antenna The power radiation pattern of the RIS electromagnetic block is calculated using the following formula, where is the variable: ; in, For radiation pattern coefficients; Based on the path loss model dataset in S1 The distance from the receiving antenna to the RIS center Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Receiver antenna gain The power radiation pattern of the receiving antenna is calculated using the following formula, where is the variable: ; Finally, the power radiation pattern of the transmitting antenna is... RIS electromagnetic block power radiation pattern Receiver antenna power radiation pattern After performing cumulative multiplication, the joint normalized power radiation pattern is obtained as follows: .

[0011] The present invention further explains that the total phase change term of the signal after reflection by the RIS electromagnetic block in S4 is specifically based on the path loss model dataset. The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block As the core variable, combined with wavelength The dynamic estimation function for the total phase change is constructed as follows: .

[0012] The present invention further explains that, in S5, the reflection amplitude of the RIS electromagnetic unit is... Compensation phase angle of RIS electromagnetic unit Using the core variable, the dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed as follows: .

[0013] The present invention further explains that, in step S6, the method is based on the joint normalized power radiation pattern. Dynamic estimation function of total phase change Dynamic estimation function of programmable reflection coefficient Combined with the total number of RIS electromagnetic blocks × , Adjustment step size The double superposition reflection gain model of the RIS electromagnetic unit performance is constructed as follows: .

[0014] The present invention further explains that, in S7, a long physical size of the RIS is introduced. and Total number of electromagnetic units Combined with the gain of the transmitting antenna Receiver antenna gain The dual superposition reflection gain model of the RIS electromagnetic unit performance is incorporated. The final path loss model method is derived by integrating the results, and its expression is: ; in, The summation order is determined by Decide.

[0015] By adopting the above technical solution, the technical solution implemented in this invention breaks through the limitation of the separation of far-field and near-field models in the path loss modeling of existing RIS-assisted communication systems, and establishes a unified theoretical framework that continuously describes the propagation characteristics from the near field to the far field. By introducing a control step size parameter, the RIS is divided into several rectangular electromagnetic blocks. The electromagnetic units within the same electromagnetic block adopt consistent or highly approximate electromagnetic response characteristics, thereby transforming the high-dimensional problem of unit-level control into a unified control problem of equivalent electromagnetic characteristics based on electromagnetic blocks as basic units, which significantly improves computational efficiency. At the same time, the control step size is dynamically adjusted according to the actual scenario requirements, realizing precise control and flexible trade-off between model simplification, computational efficiency and prediction accuracy, enhancing practicality and robustness, and providing stronger engineering applicability for low-latency processing and deployment of RIS in actual dynamic environments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method flow of the present invention; Figure 2 This is a schematic diagram of the system in Embodiment 1 of the present invention; Figure 3 This invention and Reference 1 control step size A diagram showing the comparison of predicted path loss results at different times; Figure 4 This invention and Reference 1 control step size A diagram showing the comparison of predicted path loss results at different times; Figure 5 This is a schematic diagram comparing the time consumption of the present invention and the method proposed in Reference 1 in calculating the dynamic estimation function of the total phase change; Figure 6 This is a schematic diagram comparing the time consumption of the present invention and the method proposed in Reference 1 in calculating the joint normalized power radiation pattern; Figure 7 This is a schematic diagram illustrating the efficiency improvement of the method proposed in this invention and in Reference 1 in calculating the dynamic estimation function of the total phase change and the joint normalized power radiation pattern. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] Please see Figures 1 to 7 The present invention provides the following technical solutions: Example 1 See Figures 1 to 2 , Figure 1 This is a schematic flowchart of a path loss modeling method for a RIS-assisted communication system provided according to Embodiment 1 of the present invention. Figure 1 As shown, the method includes the following steps: S1. Establish a three-dimensional coordinate system with the RIS center as the coordinate center, and construct the path loss model dataset. ; S2, Set the adjustment step size to , ,Bundle Each RIS electromagnetic unit is divided into sizes. Regular electromagnetic blocks of electromagnetic units; Among them, the adjustment step size It can be dynamically adjusted according to the real-time requirements of specific application scenarios; S3. Construct the joint normalized power radiation pattern of the transmitting antenna, RIS electromagnetic block, and receiving antenna. Specifically, calculate the power radiation pattern of the transmitting antenna, the RIS electromagnetic block, and the receiving antenna, then multiply all the patterns to obtain the joint normalized power radiation pattern. ; S4. Construct the total phase change term of the signal after reflection by the RIS electromagnetic block, based on the path loss model dataset. Combined with wavelength Construct a dynamic estimation function for the total phase change. ; S5. Construct the programmable reflection coefficient of the RIS electromagnetic unit, including the reflection amplitude of the RIS electromagnetic unit. Compensation phase angle of RIS electromagnetic unit Using the core variable, a dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed. ; S6. Based on joint normalized power radiation pattern Dynamic estimation function of total phase change and the dynamic estimation function of programmable reflection coefficient Based on the total number of RIS electromagnetic blocks, a dual superposition reflection gain model of RIS electromagnetic unit performance is constructed. ; S7, introduces RIS with long physical size and Total number of electromagnetic units Transmit antenna gain Receiver antenna gain Incorporating a dual superposition reflection gain model of RIS electromagnetic unit performance The final path loss is obtained by integration. .

[0020] Furthermore, Figure 2 This is a system schematic diagram of a path loss modeling method for RIS-assisted communication systems according to Embodiment 1 of the present invention. Based on the above implementation steps, this section further optimizes and provides an optional implementation scheme, such as... Figure 2 As shown.

[0021] The method of this invention is applicable to free-space path loss modeling in RIS-assisted wireless communication. Figure 2 The diagram omits the direct link between the transmitter and receiver. Specifically, In this embodiment, a three-dimensional coordinate system is established with the RIS center as the coordinate center, and a path loss model dataset is constructed. This includes the distance from the transmitting antenna to the RIS center. Distance from receiving antenna to RIS center Distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Coordinates of the transmitting antenna Coordinates of the receiving antenna Coordinates of the RIS electromagnetic unit Coordinates of the RIS electromagnetic block Transmit antenna gain Receiver antenna gain .

[0022] Based on the real-time requirements of the specific application scenario, determine the real-time level, and adjust the control step size according to the determined real-time level. ; Based on the determined control step size ， Determine the total number of RIS electromagnetic blocks × ,in Simultaneously, a block mapping model for RIS electromagnetic units and RIS electromagnetic blocks is established to realize RIS electromagnetic unit indexing. Index to RIS Electromagnetic Block Precise, programmable mathematical mappings. Specifically, this includes: Index standardization: unifying coordinates to a non-negative indexing system for any electromagnetic unit. Execute the following formula: ; Block index calculation: Calculating RIS electromagnetic units With RIS electromagnetic block The positional relationship is determined by the following formula: ; Membership determination: Set a fault tolerance threshold ,if: ; Then the RIS electromagnetic unit ∈RIS electromagnetic block .

[0023] Dataset based on path loss model The distance from the transmitting antenna to the RIS center Distance from the transmitting antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Transmit antenna gain The power radiation pattern of the transmitting antenna is calculated using the following formula, where is the variable: ; Dataset based on path loss model The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block Coordinates of the transmitting antenna Coordinates of the receiving antenna The power radiation pattern of the RIS electromagnetic block is calculated using the following formula, where is the variable: ; in, For radiation pattern coefficients; Dataset based on path loss model The distance from the receiving antenna to the RIS center Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Receiver antenna gain The receiving antenna power radiation pattern is calculated using the following formula, where is the variable: ; Finally, the power radiation pattern of the transmitting antenna will be analyzed. RIS electromagnetic block power radiation pattern Receiver antenna power radiation pattern After performing cumulative multiplication, the joint normalized power radiation pattern is obtained as follows: ; Dataset based on path loss model The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block As the core variable, combined with wavelength The dynamic estimation function for the total phase change is constructed as follows: ; The reflection amplitude of the RIS electromagnetic unit Compensation phase angle of RIS electromagnetic unit Using the core variable, the dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed as follows: ; Based on joint normalized power radiation pattern Dynamic estimation function of total phase change Dynamic estimation function of programmable reflection coefficient Combined with the total number of RIS electromagnetic blocks × , Adjustment step size The double superposition reflection gain model of the RIS electromagnetic unit performance is constructed as follows: ; Introducing RIS physical size long and Total number of electromagnetic units Combined with the transmit antenna gain Receiver antenna gain Incorporating a dual superposition reflection gain model of RIS electromagnetic unit performance The final path loss model method is derived by integrating the results, and its expression is: ; in, The summation order is determined by Decide.

[0024] Example 2 See Figures 3 to 7 We then quantitatively evaluated the performance of the final path loss model method. We selected path loss prediction results, computation time, and the improvement in computational efficiency as evaluation indicators, and compared them with the method proposed in Reference 1 in the background section.

[0025] The core of the method in this invention and the method proposed in Reference 1 is the double superposition reflection gain model of the RIS electromagnetic unit performance. Includes joint normalized power radiation pattern Dynamic estimation function of total phase change This involves numerous exponential and complex number operations, and the computational overhead increases exponentially with the number of RIS units. It is the most computationally expensive and time-consuming component, and a key factor affecting the real-time computational efficiency of the model. Therefore, in this embodiment, while ensuring that the parameters of the method of this invention are consistent with those of the method proposed in Reference 1, a comparative analysis is conducted on the path loss prediction results, the time required to calculate the joint normalized power radiation pattern and the dynamic estimation function of the total phase change, and the percentage improvement in computational efficiency between the two methods.

[0026] Figure 3 , Figure 4 The results show that, under different control step sizes, the path loss prediction results of the method of this invention are highly consistent with those of the method in Reference 1. Figure 5 , Figure 6 The results show that the method of the present invention is significantly more efficient than the method in reference 1 in terms of calculating the dynamic estimation function of the total phase change and the joint normalized power radiation pattern. Figure 7 The results show that, compared to the method in Reference 1, the method of this invention significantly improves computational efficiency by at least 75%, and even approaches 100%, in calculating the dynamic estimation function of the total phase change and the joint normalized power radiation pattern. Furthermore, the method of this invention can dynamically adjust the control step size according to the actual scenario requirements. This achieves a dynamic balance between computational efficiency and system performance.

[0027] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A path loss modeling method for RIS-assisted communication systems, characterized in that, Includes the following steps: S1. Establish a three-dimensional coordinate system with the RIS center as the coordinate center, and construct the path loss model dataset. ; S2, Set the adjustment step size to , ,Bundle Each RIS electromagnetic unit is divided into sizes. Regular electromagnetic blocks of electromagnetic units; Wherein, the control step size It can be dynamically adjusted according to the real-time requirements of specific application scenarios; S3. Construct the joint normalized power radiation pattern of the transmitting antenna, RIS electromagnetic block, and receiving antenna. Specifically, calculate the power radiation pattern of the transmitting antenna, the RIS electromagnetic block, and the receiving antenna, then multiply all the patterns to obtain the joint normalized power radiation pattern. ; S4. Construct the total phase change term of the signal after reflection by the RIS electromagnetic block, based on the path loss model dataset. Combined with wavelength Construct a dynamic estimation function for the total phase change. ; S5. Construct the programmable reflection coefficient of the RIS electromagnetic unit, including using the reflection amplitude of the RIS electromagnetic unit. The compensation phase angle of the RIS electromagnetic unit Using the core variable, a dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed. ; S6. Based on the aforementioned joint normalized power radiation pattern Dynamic estimation function of total phase change and the dynamic estimation function of programmable reflection coefficient Based on the total number of RIS electromagnetic blocks, a dual superposition reflection gain model of RIS electromagnetic unit performance is constructed. ; S7, introduces RIS with long physical size and Total number of electromagnetic units Transmit antenna gain Receiver antenna gain The dual superposition reflection gain model of the RIS electromagnetic unit performance is incorporated. The final path loss is obtained by integration. .

2. The path loss modeling method for RIS-assisted communication systems according to claim 1, characterized in that, The path loss model dataset in S1 This includes the distance from the transmitting antenna to the RIS center. Distance from receiving antenna to RIS center Distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Coordinates of the transmitting antenna Coordinates of the receiving antenna Coordinates of the RIS electromagnetic unit Coordinates of the RIS electromagnetic block Transmit antenna gain Receiver antenna gain .

3. The path loss modeling method for RIS-assisted communication systems according to claim 2, characterized in that, The adjustment step size in S2 Dynamic adjustment methods include: Based on the real-time requirements of the specific application scenario, a real-time level is determined, and the control step size is adjusted according to the determined real-time level. ; Based on the aforementioned control step size Determine the total number of RIS electromagnetic blocks × ,in At the same time, a block mapping model for RIS electromagnetic units and RIS electromagnetic blocks is established.

4. The path loss modeling method for RIS-assisted communication systems according to claim 3, characterized in that, The block mapping model for the RIS electromagnetic unit and RIS electromagnetic block is as follows: Establish standardization, index calculation, and membership determination formulas to realize RIS electromagnetic unit indexing. Index to RIS Electromagnetic Block Precise, programmable mathematical mappings, specifically including: Index standardization: unifying coordinates to a non-negative indexing system for any electromagnetic unit. Execute the following formula: ； Block index calculation: Calculating RIS electromagnetic units With RIS electromagnetic block The positional relationship is determined by the following formula: ； Membership determination: Set a fault tolerance threshold ,if: ； Then the RIS electromagnetic unit ∈RIS electromagnetic block .

5. The path loss modeling method for a RIS-assisted communication system according to claim 4, characterized in that, The calculation of the joint normalized power radiation pattern in S3 is specifically as follows: Based on the path loss model dataset in S1 The distance from the transmitting antenna to the center of the RIS Distance from the transmitting antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Transmit antenna gain The power radiation pattern of the transmitting antenna is calculated using the following formula, where is the variable: ； Based on the path loss model dataset in S1 The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block Coordinates of the transmitting antenna Coordinates of the receiving antenna The power radiation pattern of the RIS electromagnetic block is calculated using the following formula, where is the variable: ； in, For radiation pattern coefficients; Based on the path loss model dataset in S1 The distance from the receiving antenna to the RIS center Distance from the receiving antenna to the center of the RIS electromagnetic block From RIS electromagnetic block center to RIS center Receiver antenna gain The power radiation pattern of the receiving antenna is calculated using the following formula, where is the variable: ； Finally, the power radiation pattern of the transmitting antenna is... RIS electromagnetic block power radiation pattern Receiver antenna power radiation pattern By performing cumulative multiplication, the joint normalized power radiation pattern is obtained as follows: 。 6. The path loss modeling method for a RIS-assisted communication system according to claim 5, characterized in that: The total phase change term constructed in S4 after the signal is reflected by the RIS electromagnetic block is specifically based on the path loss model dataset. The distance from the transmitting antenna to the center of the RIS electromagnetic block Distance from the receiving antenna to the center of the RIS electromagnetic block As the core variable, combined with wavelength The dynamic estimation function for the total phase change is constructed as follows: 。 7. The path loss modeling method for RIS-assisted communication systems according to claim 6, characterized in that: In S5, the reflection amplitude of the RIS electromagnetic unit is used as an example. Compensation phase angle of RIS electromagnetic unit Using the core variable, the dynamic estimation function for the programmable reflection coefficient of the RIS electromagnetic unit is constructed as follows: 。 8. The path loss modeling method for RIS-assisted communication systems according to claim 7, characterized in that: In step S6, the joint normalized power radiation pattern is used as the basis. Dynamic estimation function of total phase change Dynamic estimation function of programmable reflection coefficient Combined with the total number of RIS electromagnetic blocks × The aforementioned adjustment step size The double superposition reflection gain model of the RIS electromagnetic unit performance is constructed as follows: 。 9. A path loss modeling method for a RIS-assisted communication system according to claim 8, characterized in that: In S7, a long physical size of RIS is introduced. and Total number of electromagnetic units Combined with the gain of the transmitting antenna Receiver antenna gain The dual superposition reflection gain model of the RIS electromagnetic unit performance is incorporated. The final path loss model method is derived by integrating the results, and its expression is: ； in, The summation order is determined by Decide.

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