Stepwise-simulation-based ray tracing modeling method and system for reconfigurable intelligent surface channel

Abstract

Provided in the present invention are a stepwise-simulation-based ray tracing modeling method and system for a reconfigurable intelligent surface (RIS) channel. The method comprises: constructing a simulation scenario, and setting simulation parameters; verifying a simulation environment layout; constructing an RIS; classifying multipaths; performing stepwise simulation to acquire multipath information; extracting a channel impulse response of the RIS; on the basis of multipath information of a first multipath and multipath information of a second multipath, extracting a channel impulse response of a cascade link of a base station, the RIS and a user to obtain a path loss, a delay power spectral density and an angular power spectral density, so as to analyze channel characteristics of an RIS channel in a delay domain and an angular domain. The present invention supports RIS channel simulation in any frequency band and any scenario, such that deterministic modeling methods for RISs are enriched, RIS channel parameters can be acquired with less manpower, fewer material resources and lower time costs, and channel characteristic analysis of simulation results has guiding significance for the application and deployment of RISs in actual communication systems.

Description

Ray tracing modeling method and system for intelligent metasurface channels based on step-by-step simulation Technical Field

[0001] The present invention belongs to the field of channel modeling technology, and in particular relates to a method and system for intelligent metasurface channel ray tracing modeling based on step-by-step simulation. Background Art

[0002] To achieve the vision of full coverage, full spectrum, full applications, full sensory, fully digital, and robust security for the sixth-generation (6G) mobile communication system, key enabling technologies such as ultra-large-scale multiple-input-multiple-output (MIMO) and terahertz (THz) communication will be incorporated into future mobile communication systems. While equipping base stations (BSs) with ultra-large-scale MIMO antenna arrays improves spatial resolution and capacity, it also increases power consumption, hardware expenses, and maintenance costs. While THz communication supports ultra-high transmission rates, high path loss (PL) and poor diffraction capability severely limit wireless communication range and application scenarios. Reconfigurable Intelligent Surfaces (RIS), also known as smart metasurfaces, stand out among the many key 6G technologies due to their programmable nature, low energy consumption, and ease of deployment, making them a potential solution for future wireless networks.

[0003] A wireless channel is the medium through which signals propagate in space. The introduction of the emerging technology RIS (Reliable Interference Response) (RIS) breaks the uncontrollable nature of traditional channels, causing them to exhibit different channel characteristics in different frequency bands and application scenarios. Accurate and effective channel models are essential for studying these characteristics. Therefore, the system design, theoretical analysis, performance evaluation, optimization, and location deployment of wireless communication systems incorporating smart metasurfaces urgently require reliable smart metasurface channel models. Traditional wireless channel research involves the following steps: first, obtaining the channel impulse response (CIR) of the actual wireless propagation environment through field channel measurements; second, estimating the channel parameters using channel estimation algorithms such as the Space-Alternating Generalized Expectation-Maximization (SAGE) algorithm; third, analyzing the channel characteristics based on the obtained CIR and channel parameters to reveal the channel characteristics; and finally, constructing a channel model and comparing the modeled channel characteristics with the measured results to verify the model's accuracy.

[0004] However, current smart metasurface channel measurement presents certain challenges. First, the RIS device itself is still in the design and development phase, making it expensive and immature. Second, the RIS's directional reflectance properties rely on the design of the RIS encoding, which in turn relies on precise positional information between the transmitter, receiver, and RIS. In actual measurements, since better RIS directional reflectance results in a narrower main lobe width, even slight deviations in the RIS's positional layout can hinder signal reception at the receiver. Furthermore, high-performance channel detectors are expensive, making channel measurement on smart metasurfaces challenging.

[0005] Summary of the Invention

[0006] In response to the deficiencies in the prior art, the present invention provides a method and system for modeling intelligent metasurface channel ray tracing based on step-by-step simulation.

[0007] In a first aspect, the present invention provides a smart metasurface channel ray tracing modeling method based on step-by-step simulation, comprising:

[0008] Determine the layout of the simulation environment and the materials to be used to draw the simulation environment;

[0009] Determine antenna parameters, transceiver layout, and signal center frequency to complete the simulation setup;

[0010] Determine the deployment location and size of the smart metasurface to complete the construction of the smart metasurface;

[0011] Determining whether the transmitted signal is reflected by the smart metasurface;

[0012] If yes, the multipath through which the transmitted signal is reflected by the smart metasurface and reaches the user is taken as the first multipath;

[0013] If not, the multipath through which the transmitted signal reaches the user without being reflected by the smart metasurface is taken as the second multipath;

[0014] The multipath information of the first multipath is obtained by step-by-step simulation; the multipath information includes the phase, delay and power of the multipath;

[0015] The material of the smart metasurface is set to an absorbing material, the transmitting and receiving antennas at the transmitting and receiving ends are set to a working state, and the receiving and transmitting antennas at the smart metasurface are set to a non-working state. The cascade link simulation of the base station, the smart metasurface and the user is performed to obtain the multipath information of the second multipath;

[0016] Based on the multipath information of the first multipath and the multipath information of the second multipath, the channel impulse response of the cascade link of the base station, the smart metasurface and the user is extracted to obtain the path loss, delay power spectral density and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and angle domain.

[0017] Furthermore, determining antenna parameters, transceiver layout, and signal center frequency to complete the simulation setup includes:

[0018] Determine the antenna type, antenna polarization mode, antenna path range, transmitter and receiver point layout, transmitter matching antenna type, receiver matching antenna type, receiver receiving power threshold, transmit signal type, transmit signal center frequency, and transmit signal bandwidth in the simulation environment;

[0019] Complete the simulation setup by determining the dielectric constant of the material based on the center frequency of the transmitted signal.

[0020] Set the simulation propagation mechanism and the maximum order of each propagation mechanism;

[0021] Set the output simulation results; the simulation results include three types of multipath information: phase, delay and power, as well as horizontal arrival angle and pitch arrival angle.

[0022] Furthermore, determining the deployment position and size of the smart metasurface to complete the construction of the smart metasurface includes:

[0023] Setting receiving points on the smart metasurface at half-wavelength intervals to obtain the receiving power at the smart metasurface;

[0024] A transmitting point is set at the center of the smart metasurface to obtain multipath information of the first multipath.

[0025] Furthermore, the step-by-step simulation to obtain multipath information of the first multipath includes:

[0026] Assume that the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface are both in working state, and the transmitting antenna at the smart metasurface and the receiving antenna at the receiving end are both in non-working state, and perform the base station-smart metasurface segment simulation;

[0027] The simulation obtains the receiving power and phase from the base station to each receiving point on the smart metasurface;

[0028] The total received power P at the smart metasurface is calculated according to the following formula: RIS :

[0029] Among them, M is the total number of rows of receiving points in the horizontal direction of the smart metasurface, N is the total number of columns of receiving points in the vertical direction of the smart metasurface, and the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface, Φm,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k=2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector pointing from the center of the smart metasurface to the user; e is a natural constant, and j is an imaginary unit;

[0030] The smart metasurface is used as a secondary emission source, the connection direction between the smart metasurface and the user is used as the reflection direction, and the main lobe width of the smart metasurface is used as the pathfinding range. The link between the smart metasurface and the user is simulated to obtain the first multipath reflected by the smart metasurface to the user.

[0031] The total delay of the first multipath is calculated according to the following formula

[0032] Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface.

[0033] Furthermore, the multipath information of the first multipath and the multipath information of the second multipath are used to extract the channel impulse response of the cascade link of the base station, the smart metasurface, and the user, and obtain the path loss, delay power spectral density, and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and the angle domain, including:

[0034] Construct the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair i,q (f) to characterize the attenuation and distortion of the signal during transmission:

[0035] Where L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ l is the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit;

[0036] According to the transmission signal bandwidth and time domain signal length, H i,q (f) performing frequency domain sampling to obtain a discrete channel transfer function;

[0037] The discrete channel transfer function is processed by inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q ;

[0038] The channel impulse responses of different receiving antenna pairs are averaged along the antenna dimension, and the channel impulse response h(t) between the transmitter and receiver is calculated according to the following formula:

[0039] Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end.

[0040] In a second aspect, the present invention provides an intelligent metasurface channel ray tracing modeling system based on step-by-step simulation, comprising:

[0041] A simulation environment drawing module, used for determining the layout of the simulation environment and the materials to be applied so as to draw the simulation environment;

[0042] The simulation setup completion module is used to determine antenna parameters, transceiver layout, and signal center frequency to complete the simulation setup;

[0043] An intelligent metasurface construction module, used to determine the deployment location and size of the intelligent metasurface to complete the construction of the intelligent metasurface;

[0044] A judgment module, used to judge whether the transmitted signal is reflected by the smart metasurface;

[0045] A first determining module is configured to, when the judging module determines that the transmitted signal is reflected by the smart metasurface, determine a multipath through which the transmitted signal is reflected by the smart metasurface to reach the user as a first multipath;

[0046] A second determining module is configured to, when the judging module determines that the transmitted signal is not reflected by the smart metasurface, determine a multipath in which the transmitted signal reaches the user without being reflected by the smart metasurface as a second multipath;

[0047] A first multipath information acquisition module is used to obtain multipath information of the first multipath through step-by-step simulation; the multipath information includes phase, delay and power of the multipath;

[0048] The second multipath information acquisition module is used to set the material of the smart metasurface to an absorbing material, set the transmitting and receiving antennas at the transmitting end and the receiving end to an operating state, and the receiving and transmitting antennas at the smart metasurface to a non-operating state, and perform a cascade link simulation of the base station, the smart metasurface, and the user to obtain multipath information of the second multipath;

[0049] The channel characteristic analysis module is used to extract the channel impulse response of the cascade link of the base station, the smart metasurface and the user based on the multipath information of the first multipath and the multipath information of the second multipath, and obtain the path loss, delay power spectral density and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and angle domain.

[0050] Furthermore, the simulation setting completion module includes:

[0051] The first determination unit is used to determine the antenna type, antenna polarization mode, antenna path range, point layout of the transmitter and the receiver, the transmitting antenna type matched by the transmitter, the receiving antenna type matched by the receiver, the receiving power threshold of the receiver, the transmission signal type, the transmission signal center frequency and the transmission signal bandwidth in the simulation environment;

[0052] A second determining unit is used to determine the dielectric constant of the material according to the center frequency of the transmitted signal to complete the simulation setting;

[0053] A first setting unit is used to set the simulation propagation mechanism and the highest order of each propagation mechanism;

[0054] The second setting unit is used to set the output simulation results; the simulation results include three types of multipath information: multipath phase, time delay and power, as well as horizontal arrival angle and pitch arrival angle.

[0055] Furthermore, the intelligent metasurface building module includes:

[0056] A receiving power acquisition unit is used to set receiving points at half-wavelength intervals on the smart metasurface to obtain the receiving power at the smart metasurface;

[0057] The first multipath information acquisition unit is used to set a transmission point at the center of the smart metasurface to obtain multipath information of the first multipath.

[0058] Furthermore, the first multipath information acquisition module includes:

[0059] The first simulation unit is used to set the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface to be in working state, and the transmitting antenna at the smart metasurface and the receiving antenna at the receiving end to be in non-working state, and perform base station-smart metasurface section simulation;

[0060] The second simulation unit is used to simulate and obtain the receiving power and phase from the base station to each receiving point on the smart metasurface;

[0061] The first calculation unit is used to calculate the total received power P at the smart metasurface according to the following formula RIS :

[0062] Among them, M is the total number of rows of receiving points in the horizontal direction of the smart metasurface, N is the total number of columns of receiving points in the vertical direction of the smart metasurface, and the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface, Φ m,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k=2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector pointing from the center of the smart metasurface to the user; e is a natural constant, and j is an imaginary unit;

[0063] The third simulation unit is used to use the smart metasurface as a secondary emission source, the connection direction between the smart metasurface and the user as the reflection direction, and the main lobe width of the smart metasurface as the path finding range to simulate the link between the smart metasurface and the user, and obtain a first multipath reflected by the smart metasurface to the user;

[0064] The second calculation unit is used to calculate the total delay of the first multipath according to the following formula

[0065] Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface.

[0066] Furthermore, the channel characteristic analysis module includes:

[0067] A construction unit for constructing the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair i,q (f) to characterize the attenuation and distortion of the signal during transmission:

[0068] Where L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ lis the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit;

[0069] The frequency domain sampling unit is used to sample H according to the transmission signal bandwidth and time domain signal length. i,q (f) performing frequency domain sampling to obtain a discrete channel transfer function;

[0070] The inverse Fourier transform unit is used to process the discrete channel transfer function using the inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q ;

[0071] The third calculation unit is configured to average the channel impulse responses of different receiving antenna pairs along the antenna dimension and calculate the channel impulse response h(t) between the transmitting end and the receiving end according to the following formula:

[0072] Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end.

[0073] The present invention provides a ray tracing modeling method and system for an intelligent metasurface channel based on step-by-step simulation. The method can realize the directional reflection characteristics of the intelligent metasurface in static ray tracing simulation software. The unit size of the intelligent metasurface is strictly designed according to the theoretically required half-wavelength size, and any number of intelligent metasurface units can be deployed in any position in the environment in any arrangement to realize ray tracing simulation of the intelligent metasurface channel in any frequency band and any scenario. The intelligent metasurface channel parameters can be obtained with low manpower, material resources and time costs, and the intelligent metasurface channel characteristics can be analyzed, laying the foundation for the application of intelligent metasurfaces in actual communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0075] FIG1 is a flow chart of a ray tracing modeling method for an intelligent metasurface channel based on step-by-step simulation provided by an embodiment of the present invention;

[0076] FIG2 is a schematic diagram of multipath classification provided by an embodiment of the present invention;

[0077] FIG3 is a schematic diagram of the incident path and reflection path of the smart metasurface provided by an embodiment of the present invention;

[0078] FIG4 is a schematic diagram of a smart metasurface simulation scenario provided by an embodiment of the present invention;

[0079] FIG5 is a fitting diagram of the UE1-UE20 path loss and measurement data provided by an embodiment of the present invention;

[0080] FIG6 is a diagram of the absolute error of the UE1-UE20 path loss and measurement data provided by an embodiment of the present invention;

[0081] FIG7 is a fitting diagram of the delay power density spectrum of UE1 in the RIS mirror placement state and the measurement data provided by an embodiment of the present invention;

[0082] FIG8 is a fitting diagram of the delay power density spectrum of UE5 in the non-mirror state of RIS and the measured data provided by an embodiment of the present invention;

[0083] FIG9 is an angular power spectrum density diagram of UE2 in a RIS mirror placement state according to an embodiment of the present invention;

[0084] FIG10 is an angular power spectrum density diagram of UE5 in a non-mirror display state of the RIS according to an embodiment of the present invention;

[0085] Figure 11 is a structural diagram of an intelligent metasurface channel ray tracing modeling system based on step-by-step simulation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0086] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0087] Deterministic channel modeling and simulation analysis based on ray tracing (RT) is expected to overcome the current difficulties in smart metasurface channel measurement. Ray tracing, based on geometric optics (GO) and the uniform theory of diffraction (UTD), enables the search for propagation paths of electromagnetic waves under different propagation mechanisms, such as direct radiation, reflection, and diffraction. Although current ray tracing simulation software itself cannot break through the reflection law in geometric optics to achieve the directional reflection characteristics of smart metasurfaces, as long as reasonable and effective smart metasurface modeling and simulation methods can be proposed, combined with the efficient computing power and flexible parameter configuration advantages of ray tracing simulation software itself, smart metasurface channel modeling and simulation can be achieved in any frequency band and any scenario. This allows obtaining channel information of smart metasurface channels with low manpower, material resources, and time costs, and then analyzing their channel characteristics. This will lay the foundation for the future deployment and application of RIS in practical application scenarios, which is of far-reaching significance.

[0088] In one embodiment, as shown in FIG1 , an embodiment of the present invention provides a ray tracing modeling method for an intelligent metasurface channel based on step-by-step simulation, comprising:

[0089] Step 101 : Determine the layout of the simulation environment and the materials to be applied to draw the simulation environment.

[0090] For example, a deterministic channel modeling method based on ray tracing is used. First, the application scenario is determined to be an "L"-shaped office area. The test environment is shown in Figure 4. An 18.8×40×3.3m 3 The public office area is a 2.4×32×3.3m 3 The corridor connects the office area. One side of the corridor is made of concrete and metal, while the other side is made of transparent glass and wood. The public office area is separated at both ends by the transparent glass and wooden doors of the conference room. The center is mainly composed of neatly arranged desks, chairs, and load-bearing columns. The walls surrounding the desks, load-bearing columns, and one side of the corridor are mostly metal, while the other side is equipped with transparent glass windows. In addition, a wooden table approximately 0.8m high and 1.2m long was placed at the corner of the office area and the corridor to accommodate the metal plates and intelligent metasurface (RIS) used for measurement. Material parameters for the walls, windows, doors, and floors were also determined.

[0091] Step 102: Determine antenna parameters, transceiver layout, and signal center frequency to complete simulation settings.

[0092] For example, the base station (BS) is a 4×8 dual-polarization array antenna, fixed in a long corridor. The user equipment (UE) is a dual-polarization cylindrical array antenna, located at 20 locations within the office corridor, evenly spaced at 1.2m intervals. All UEs, BSs, and RIS centers are at the same height.

[0093] In this embodiment, the parameters of antenna, transceiver layout, signal waveform, etc. are set as follows:

[0094] Step 1021: Determine the antenna type, antenna polarization mode, and antenna routing range in the simulation environment (based on the determined application scenario); the point layout of the transmitter and receiver, the transmitting antenna type matched by the transmitter, the receiving antenna type matched by the receiver, and the receiving power threshold of the receiver; the transmitted signal type, center frequency, and signal bandwidth.

[0095] As shown in Figure 4, the global coordinate system has its origin at the lower right vertex of the scene, O. The walls on both sides extend in the positive directions of the X and Y axes, respectively, and the Z axis is perpendicular to the ground. The BS coordinates in the global coordinate system are (26, 1.2, 1.3). The BS local coordinate system has its origin at the BS center, O'. The direction of the line connecting the BS center and the RIS center is the positive Y' direction, the direction perpendicular to the ground is the positive Z' direction, and the X' axis is perpendicular to both the Y' and Z' axes. The UE local coordinate system has its origin at the UE center, the direction of the line connecting the UE center and the RIS center is the positive Y" direction, the direction perpendicular to the ground is the positive Z" direction, and the X" axis is perpendicular to both the Y" and Z" axes.

[0096] Using the BS's local coordinate system as a reference, the raycast range is set to 0°-180° horizontally and 0°-180° in elevation, with rays uniformly launched at 0.25° intervals for pathfinding. UE1's coordinates in the global coordinate system are (17.6, 2.4, 1.3). Starting from UE1, 20 receiving points (UE1-UE20) are placed every 1.2 meters along the positive Y-axis of the global coordinate system. The coordinates are in meters. The transmitter's signal center frequency is 5.4 GHz, and the signal bandwidth is 160 MHz.

[0097] Step 1022 , determining the dielectric constant of the material according to the center frequency of the transmitted signal to complete the simulation setting.

[0098] Based on the center frequency of 5.4 GHz, the dielectric constants of materials such as glass, drywall, tiles, and metal used in the environment were corrected to complete the simulation settings.

[0099] Step S1023: setting the simulation propagation mechanism and the highest order of each propagation mechanism.

[0100] Considering the reflection and diffraction mechanisms, illustratively, the highest reflection order is 3rd order and the highest diffraction order is 1st order.

[0101] Step S1024: Set the type of simulation result to be output. The simulation result includes three types of multipath information: phase, delay, and power, as well as horizontal arrival angle and elevation arrival angle.

[0102] Step 103: Determine the deployment location and size of the smart metasurface to complete the construction of the smart metasurface.

[0103] In this embodiment, a ray tracing simulation is performed in a scenario where RIS is not deployed, and the path loss obtained by the simulation is compared and verified with the actual measurement data to ensure the accuracy of the scenario construction.

[0104] For example, the RIS contains 24×24 units and has a size of 624×624 mm. 2 The operating angle range is ±60° in two dimensions, and the horizontal 3-dB bandwidth is approximately 14°. The RIS center coordinates are (17.6, 1.2, 1.3) in meters.

[0105] On the RIS board plane, 24 × 24 receiving points were placed at half-wavelength intervals to obtain the received power at the RIS. A transmitting point was placed at the center of the RIS for subsequent RIS-UE link simulation.

[0106] Step 104: Determine whether the transmitted signal is reflected by the smart metasurface.

[0107] As shown in Figure 2, the multipath components in the propagation environment are classified according to whether they are reflected by the RIS surface. One type is the multipath MP that reaches the UE through directional reflection on the RIS surface. RIS The other type is multipath MP, which does not interact with the RIS surface and reaches the UE through multiple reflections or diffractions from other elements in the environment. non-RIS .

[0108] Step 105: If yes, the multipath through which the transmitted signal is reflected by the smart metasurface and reaches the user is taken as the first multipath.

[0109] Step 106: If not, the multipath through which the transmitted signal reaches the user without being reflected by the smart metasurface is taken as the second multipath.

[0110] Step 107, obtaining multipath information of the first multipath by step-by-step simulation; the multipath information includes phase, delay, and power of the multipath;

[0111] For example, this step involves assuming both the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface are in active mode, and both the transmitting antenna at the smart metasurface and the receiving antenna at the receiving end are in inactive mode, and then performing a simulation of the base station-smart metasurface segment. The RIS board has 24 receiving points in both the horizontal and vertical directions, for a total of 576.

[0112] The received power and phase from the base station to each receiving point on the smart metasurface are obtained by simulation. Then, the phase obtained by RIS optimal coding is superimposed in Matlab to calculate the total received power at the RIS.

[0113] The total received power P at the smart metasurface is calculated according to the following formula: RIS :

[0114] Where M is the total number of rows of receiving points in the horizontal direction of the smart metasurface, and N is the total number of columns of receiving points in the vertical direction of the smart metasurface. As shown in Figure 3, the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface. Since the current ray tracing simulation software is based on the far-field assumption, the far-field coding method is adopted. m,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k=2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector pointing from the center of the smart metasurface to the user; e is a natural constant, and j is an imaginary unit.

[0115] The intelligent metasurface is used as a secondary emission source, the connection direction between the intelligent metasurface and the user is used as the reflection direction, and the main lobe width of the intelligent metasurface (horizontally ±7°, in elevation ±60°) is used as the pathfinding range. The intelligent metasurface and user link are simulated to obtain the first multipath MP that reaches the user through the reflection of the intelligent metasurface. RIS It should be noted that the MP obtained by simulation RIS In the multipath information, the delay only includes the RIS-UE segment path delay, so the BS-RIS segment path delay needs to be added. Since BS-RIS is a line-of-sight scenario, when calculating MP RIS The delay plus Get the total delay.

[0116] The total delay of the first multipath is calculated according to the following formula

[0117] Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface, which is 8.4 m in this embodiment.

[0118] Step 108: Set the material of the smart metasurface to an absorbing material, set the transmitting and receiving antennas at the transmitting and receiving ends to a working state, and the receiving and transmitting antennas at the smart metasurface to a non-working state, and perform a cascade link simulation of the base station, the smart metasurface, and the user to obtain multipath information of the second multipath.

[0119] Step 109: Extract the channel impulse response of the cascade link of the base station, the smart metasurface, and the user based on the multipath information of the first multipath and the multipath information of the second multipath, and obtain the path loss, delay power spectral density, and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and angle domain.

[0120] Integrate all multipath information in the propagation environment and construct the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair i,q (f) to characterize the attenuation and distortion of the signal during transmission:

[0121] Where L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ l is the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit.

[0122] According to the measurement bandwidth of 160MHz and the PN sequence length of 1023 used to verify the accuracy of the modeling method, the frequency domain sampling interval Δf is 0.156MHz. According to the transmission signal bandwidth and time domain signal length, H i,q (f) Perform frequency domain sampling to obtain the discrete channel transfer function.

[0123] The discrete channel transfer function is processed by inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q .

[0124] The channel impulse responses of different receiving antenna pairs are averaged along the antenna dimension, and the channel impulse response h(t) between the transmitter and receiver is calculated according to the following formula:

[0125] Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end. In this embodiment, N Tx The value is 64, N Rx The value is 32. For comparison results of path loss, delay power spectral density, and angle power spectral density with the verification data, see Figures 5 to 10.

[0126] The intelligent metasurface channel ray tracing modeling method based on step-by-step simulation provided by the embodiment of the present invention can be used in static ray tracing simulation software, supports intelligent metasurface channel simulation in any frequency band and any scenario, enriches the deterministic modeling method of intelligent metasurfaces, and can obtain intelligent metasurface channel parameters with lower manpower, material and time costs. The channel characteristic analysis of the simulation results has guiding significance for the application and deployment of RIS in actual communication systems.

[0127] Based on the same inventive concept, an embodiment of the present invention also provides an intelligent metasurface channel ray tracing modeling system based on step-by-step simulation. Since the principle of solving the problem by this system is similar to the aforementioned intelligent metasurface channel ray tracing modeling method based on step-by-step simulation, the implementation of this system can refer to the implementation of the intelligent metasurface channel ray tracing modeling method based on step-by-step simulation, and the repeated parts will not be repeated.

[0128] In another embodiment, the intelligent metasurface channel ray tracing modeling system based on step-by-step simulation provided by an embodiment of the present invention, as shown in FIG11 , includes:

[0129] The simulation environment drawing module 10 is used to determine the layout of the simulation environment and the materials to be applied so as to draw the simulation environment.

[0130] The simulation setting completion module 20 is used to determine antenna parameters, transceiver layout and signal center frequency to complete the simulation setting.

[0131] The intelligent metasurface construction module 30 is used to determine the deployment position and size of the intelligent metasurface to complete the construction of the intelligent metasurface.

[0132] The judgment module 40 is used to judge whether the transmitted signal is reflected by the smart metasurface.

[0133] The first determination module 50 is configured to determine, when the judgment module determines that the transmitted signal is reflected by the smart metasurface, a multipath through which the transmitted signal reaches the user via the smart metasurface as a first multipath.

[0134] The second determination module 60 is configured to determine, when the judgment module determines that the transmitted signal is not reflected by the smart metasurface, a multipath in which the transmitted signal reaches the user without being reflected by the smart metasurface as a second multipath.

[0135] The first multipath information acquisition module 70 is used to obtain the multipath information of the first multipath by step-by-step simulation; the multipath information includes the phase, delay and power of the multipath.

[0136] The second multipath information acquisition module 80 is used to set the material of the smart metasurface to an absorbing material, set the transmitting and receiving antennas at the transmitting and receiving ends to a working state, and the receiving and transmitting antennas at the smart metasurface to a non-working state, and perform a cascade link simulation of the base station, the smart metasurface and the user to obtain the multipath information of the second multipath.

[0137] The channel characteristic analysis module 90 is used to extract the channel impulse response of the cascade link of the base station, the smart metasurface and the user based on the multipath information of the first multipath and the multipath information of the second multipath, and obtain the path loss, delay power spectral density and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and angle domain.

[0138] Exemplarily, the simulation setting completion module includes:

[0139] The first determination unit is used to determine the antenna type, antenna polarization mode, antenna path range, point layout of the transmitter and the receiver, the transmitting antenna type matched by the transmitter, the receiving antenna type matched by the receiver, the receiving power threshold of the receiver, the transmission signal type, the transmission signal center frequency and the transmission signal bandwidth in a simulation environment.

[0140] The second determining unit is used to determine the dielectric constant of the material according to the center frequency of the transmitted signal to complete the simulation setting.

[0141] The first setting unit is used to set the simulation propagation mechanism and the highest order of each propagation mechanism.

[0142] The second setting unit is used to set the output simulation results; the simulation results include three types of multipath information: multipath phase, time delay and power, as well as horizontal arrival angle and pitch arrival angle.

[0143] Exemplarily, the smart metasurface building block includes:

[0144] The receiving power acquisition unit is used to set receiving points on the smart metasurface at half-wavelength intervals to obtain the receiving power at the smart metasurface.

[0145] The first multipath information acquisition unit is used to set a transmission point at the center of the smart metasurface to obtain multipath information of the first multipath.

[0146] Exemplarily, the first multipath information acquisition module includes:

[0147] The first simulation unit is used to set the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface to be in working state, and the transmitting antenna at the smart metasurface and the receiving antenna at the receiving end to be in non-working state, to perform base station-smart metasurface segment simulation.

[0148] The second simulation unit is used to simulate and obtain the receiving power and phase from the base station to each receiving point on the smart metasurface.

[0149] The first calculation unit is used to calculate the total received power P at the smart metasurface according to the following formula RIS :

[0150] Among them, M is the total number of rows of receiving points in the horizontal direction of the smart metasurface, N is the total number of columns of receiving points in the vertical direction of the smart metasurface, and the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface, Φ m,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k=2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector pointing from the center of the smart metasurface to the user; e is a natural constant, and j is an imaginary unit.

[0151] The third simulation unit is used to use the smart metasurface as a secondary emission source, the connection direction between the smart metasurface and the user as the reflection direction, and the main lobe width of the smart metasurface as the path-finding range to simulate the smart metasurface and user link to obtain the first multipath that reaches the user through reflection from the smart metasurface.

[0152] The second calculation unit is used to calculate the total delay of the first multipath according to the following formula

[0153] Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface.

[0154] Exemplarily, the channel characteristic analysis module includes:

[0155] A construction unit for constructing the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair i,q (f) to characterize the attenuation and distortion of the signal during transmission:

[0156] Where L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ l is the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit.

[0157] The frequency domain sampling unit is used to sample H according to the transmission signal bandwidth and time domain signal length. i,q (f) Perform frequency domain sampling to obtain the discrete channel transfer function.

[0158] The inverse Fourier transform unit is used to process the discrete channel transfer function using the inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q .

[0159] The third calculation unit is configured to average the channel impulse responses of different receiving antenna pairs along the antenna dimension and calculate the channel impulse response h(t) between the transmitting end and the receiving end according to the following formula:

[0160] Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end.

[0161] For more specific working processes of the above modules, please refer to the corresponding contents disclosed in the above embodiments, which will not be repeated here.

[0162] In another embodiment, the present invention provides a computer device comprising a processor and a memory; wherein, when the processor executes a computer program stored in the memory, the steps of the above-mentioned intelligent metasurface channel ray tracing modeling method based on step-by-step simulation are implemented.

[0163] For more specific details about the above method, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be described again here.

[0164] In another embodiment, the present invention provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the above-mentioned intelligent metasurface channel ray tracing modeling method based on step-by-step simulation are implemented.

[0165] For more specific details about the above method, please refer to the corresponding contents disclosed in the aforementioned embodiments, which will not be described again here.

[0166] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. References to the same or similar parts between the various embodiments will be sufficient. The systems, devices, and storage media disclosed in the embodiments are described briefly because they correspond to the methods disclosed in the embodiments. For relevant details, refer to the method description.

[0167] Those skilled in the art will clearly understand that the techniques in the embodiments of the present invention can be implemented using software plus a necessary general-purpose hardware platform. Based on this understanding, the technical solutions in the embodiments of the present invention, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention or certain portions of the embodiments.

[0168] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A ray tracing modeling method for intelligent metasurface channels based on step-by-step simulation, characterized in that: include: Determine the layout of the simulation environment and the materials used to draw the simulation environment; Determine antenna parameters, transceiver layout, and signal center frequency to complete the simulation setup; Determine the deployment location and size of the smart metasurface to complete the construction of the smart metasurface; Determine whether the transmitted signal is reflected by the smart metasurface; If yes, the multipath through which the transmitted signal is reflected by the smart metasurface and reaches the user is taken as the first multipath; If not, the multipath through which the transmitted signal reaches the user without being reflected by the smart metasurface is taken as the second multipath; The multipath information of the first multipath is obtained by step-by-step simulation; the multipath information includes the phase, delay and power of the multipath; The material of the smart metasurface is set to an absorbing material, the transmitting and receiving antennas at the transmitting end and the receiving end are set to a working state, and the receiving and transmitting antennas at the smart metasurface are set to a non-working state, and a cascade link simulation of the base station, the smart metasurface and the user is performed to obtain multipath information of the second multipath; According to the multipath information of the first multipath and the multipath information of the second multipath, the channel impulse response of the cascade link of the base station, the smart metasurface and the user is extracted to obtain the path loss, delay power spectral density and angle power spectral density to analyze the channel characteristics of the smart metasurface channel in the delay domain and angle domain.

2. The intelligent metasurface channel ray tracing modeling method based on step-by-step simulation according to claim 1 is characterized in that: Determining antenna parameters, transceiver layout, and signal center frequency to complete simulation settings includes: Determine the antenna type, antenna polarization mode, antenna path finding range, point layout of the transmitter and receiver, the transmitting antenna type matched by the transmitter, the receiving antenna type matched by the receiver, the receiving power threshold of the receiver, the transmitting signal type, the transmitting signal center frequency and the transmitting signal bandwidth in the simulation environment; Complete the simulation setup by determining the dielectric constant of the material based on the center frequency of the transmitted signal; Set the simulation propagation mechanism and the maximum order of each propagation mechanism; The simulation results are set to be output; the simulation results include three types of multipath information: phase, delay and power, as well as horizontal arrival angle and elevation arrival angle.

3. The intelligent metasurface channel ray tracing modeling method based on step-by-step simulation according to claim 1 is characterized in that: Determining the deployment position and size of the intelligent super surface to complete the construction of the intelligent super surface includes: Receiving points are set on the smart metasurface at half-wavelength intervals to obtain receiving power at the smart metasurface; A transmitting point is set at the center of the smart metasurface to obtain multipath information of the first multipath.

4. The intelligent metasurface channel ray tracing modeling method based on step-by-step simulation according to claim 1, characterized in that: The step-by-step simulation to obtain multipath information of the first multipath includes: Assume that the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface are both in working state. The receiving antennas at the receiving end are all in non-working state, and the base station-intelligent metasurface segment simulation is performed; Simulate and obtain the receiving power and phase from the base station to each receiving point on the smart metasurface; The total received power P at the smart metasurface is calculated according to the following formula: RIS : Where M is the total number of rows of receiving points on the horizontal direction of the smart metasurface, N is the total number of columns of receiving points on the vertical direction of the smart metasurface, and the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface, Φ m,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k = 2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector of the center of the smart metasurface pointing to the user; e is a natural constant, and j is an imaginary unit; The smart metasurface is used as a secondary emission source, the connection direction between the smart metasurface and the user is used as the reflection direction, and the main lobe width of the smart metasurface is used as the path-finding range. The smart metasurface and user link are simulated to obtain the first multipath that reaches the user through reflection from the smart metasurface. The total delay of the first multipath is calculated according to the following formula Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface.

5. The intelligent metasurface channel ray tracing modeling method based on step-by-step simulation according to claim 1, characterized in that: The method extracts the channel impulse response of the cascaded link of the base station, the smart metasurface and the user according to the multipath information of the first multipath and the multipath information of the second multipath, obtains the path loss, the delay power spectrum density and the angle power spectrum density, so as to analyze the channel characteristics of the smart metasurface channel in the delay domain and the angle domain, including: Construct the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair i,q (f) to characterize the attenuation and distortion of the signal during transmission: Wherein, L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ l is the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit; According to the transmission signal bandwidth and time domain signal length, H i,q (f) performing frequency domain sampling to obtain a discrete channel transfer function; The discrete channel transfer function is processed by inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q ; The channel impulse responses of different receiving antenna pairs are averaged along the antenna dimension, and the channel impulse response h(t) between the transmitter and the receiver is calculated according to the following formula: Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end.

6. A smart metasurface channel ray tracing modeling system based on step-by-step simulation, characterized in that: include: A simulation environment drawing module, used to determine the layout of the simulation environment and the materials to be applied so as to draw the simulation environment; The simulation setup completion module is used to determine antenna parameters, transceiver layout, and signal center frequency to complete the simulation setup; An intelligent metasurface construction module, used to determine the deployment position and size of the intelligent metasurface to complete the construction of the intelligent metasurface; A judgment module, used to judge whether the transmitted signal is reflected by the smart metasurface; A first determination module is used to determine, when the judgment module determines that the transmitted signal is reflected by the intelligent super surface, a multipath through which the transmitted signal is reflected by the intelligent super surface to reach the user as a first multipath; A second determination module is used to determine, when the judgment module determines that the transmitted signal is not reflected by the smart metasurface, a multipath through which the transmitted signal reaches the user without being reflected by the smart metasurface as a second multipath; A first multipath information acquisition module, used for obtaining multipath information of the first multipath by step-by-step simulation; the multipath information includes phase, delay and power of the multipath; The second multipath information acquisition module is used to set the material of the smart metasurface to an absorbing material, set the transmitting and receiving antennas at the transmitting end and the receiving end to be in a working state, and the receiving and transmitting antennas at the smart metasurface to be in a non-working state, and perform a cascade link simulation of the base station, the smart metasurface and the user to obtain multipath information of the second multipath; The channel characteristic analysis module is used to extract the channel impulse response of the cascade link of the base station, the intelligent metasurface and the user according to the multipath information of the first multipath and the multipath information of the second multipath, and obtain the path loss, delay power spectral density and angle power spectral density to analyze the channel characteristics of the intelligent metasurface channel in the delay domain and angle domain.

7. The intelligent metasurface channel ray tracing modeling system based on step-by-step simulation according to claim 6, characterized in that: The simulation setting completion module includes: The first determination unit is used to determine the antenna type, antenna polarization mode, antenna path finding range, point layout of the transmitter and the receiver, the transmitting antenna type matched by the transmitter, the receiving antenna type matched by the receiver, and the receiving antenna type matched by the receiver in the simulation environment. Receive power threshold, transmit signal type, transmit signal center frequency and transmit signal bandwidth; A second determination unit is used to determine the dielectric constant of the material according to the center frequency of the transmission signal to complete the simulation setting; A first setting unit is used to set the simulation propagation mechanism and the highest order of each propagation mechanism; The second setting unit is used to set the output simulation results; the simulation results include three types of multipath information, namely, multipath phase, time delay and power, as well as horizontal arrival angle and elevation arrival angle.

8. The intelligent metasurface channel ray tracing modeling system based on step-by-step simulation according to claim 6, characterized in that: The smart metasurface building blocks include: A receiving power acquisition unit, used to set receiving points on the smart metasurface at half-wavelength intervals to obtain the receiving power at the smart metasurface; The first multipath information acquisition unit is used to set a transmission point at the center of the smart metasurface to obtain multipath information of the first multipath.

9. The intelligent metasurface channel ray tracing modeling system based on step-by-step simulation according to claim 6, characterized in that: The first multipath information acquisition module includes: The first simulation unit is used to set the transmitting antenna at the transmitting end and the receiving antenna at the smart metasurface to be in working state, and the transmitting antenna at the smart metasurface and the receiving antenna at the receiving end to be in non-working state, and perform a base station-smart metasurface segment simulation; The second simulation unit is used to simulate and obtain the receiving power and phase from the base station to each receiving point on the smart super surface; The first calculation unit is used to calculate the total received power P at the smart metasurface according to the following formula: RIS : Where M is the total number of rows of receiving points on the horizontal direction of the smart metasurface, N is the total number of columns of receiving points on the vertical direction of the smart metasurface, and the smart metasurface has a total of M×N receiving points; P m,n is the received power of the receiving point at the mth row and nth column of the smart metasurface; is the phase of the receiving point at the mth row and nth column of the smart metasurface; Φ m,n is the coding phase of the receiving point at the mth row and nth column of the smart metasurface, Φ m,n =mod(k(v m,n v T -v m,n v R ), 2π), k is the wave number, k = 2π / λ, λ is the wavelength, v m,n v is the vector pointing from the center of the smart metasurface to the receiving point in the mth row and nth column of the smart metasurface; T v is the unit vector pointing from the center of the smart metasurface to the base station; R is the unit vector of the center of the smart metasurface pointing to the user; e is a natural constant, and j is an imaginary unit; The third simulation unit is used to use the smart metasurface as a secondary emission source, the connection direction between the smart metasurface and the user as a reflection direction, and the main lobe width of the smart metasurface as a path-finding range to simulate the smart metasurface and the user link to obtain a first multipath that reaches the user through reflection from the smart metasurface; The second calculation unit is used to calculate the total delay of the first multipath according to the following formula Among them, τ RIS-UE is the delay of each multipath in the first multipath between the smart metasurface and the user segment; c is the speed of light; is the distance from the center O of the base station to the center R of the smart metasurface.

10. The intelligent metasurface channel ray tracing modeling system based on step-by-step simulation according to claim 6, characterized in that: The channel characteristic analysis module comprises: A construction unit is used to construct the channel transfer function H of the i-th transmitting antenna and the q-th receiving antenna pair. i,q (f) to characterize the attenuation and distortion of the signal during transmission: Wherein, L is the total number of multipaths between the i-th transmitting antenna and the q-th receiving antenna; the multipaths between the i-th transmitting antenna and the q-th receiving antenna include the first multipath and the second multipath; p l is the power of the lth multipath; is the phase of the lth multipath; τ l is the time delay of the lth multipath; f is the frequency of the transmitted signal; e is a natural constant, and j is an imaginary unit; The frequency domain sampling unit is used to sample H according to the transmission signal bandwidth and the time domain signal length. i,q (f) performing frequency domain sampling to obtain a discrete channel transfer function; The inverse Fourier transform unit is used to process the discrete channel transfer function using the inverse fast Fourier transform to obtain the channel impulse response h of the i-th transmitting antenna and the q-th receiving antenna pair with the same sampling rate and length as the verification data. i,q ; The third calculation unit is used to average the channel impulse responses of different receiving antenna pairs along the antenna dimension, and calculate the channel impulse response h(t) between the transmitting end and the receiving end according to the following formula: Among them, N Tx N is the number of antenna arrays at the transmitting end; Rx is the number of antenna arrays at the receiving end.

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