A method and system for pairing users with intelligent reflective surfaces to improve wireless transmission capacity

Abstract

The present invention discloses a method and system for pairing users and intelligent reflecting surfaces for improving wireless transmission capacity, belonging to the field of wireless communication technology. The method comprises the following steps: obtaining channel state information of a direct link between a source node and each destination node and channel state information of a cascade link between the source node and each destination node via each intelligent reflecting surface; calculating a phase shift matrix of the intelligent reflecting surface based on the channel state information of the direct link and the cascade link; calculating the channel capacity of the total link between the source node and each destination node assisted by each intelligent reflecting surface based on the channel state information of the direct link and the cascade link and the phase shift matrix of the intelligent reflecting surface; screening out the maximum value of the channel capacity using a maximum priority algorithm, combining the user and intelligent reflecting surface corresponding to the maximum value as a pairing result, and the sum of the maximum values corresponding to all users as the wireless transmission capacity. Compared with traditional multi-user systems and multi-user systems assisted by a single intelligent reflecting surface, the method proposed by the present invention improves wireless transmission capacity and reduces the complexity of intelligent reflecting surface phase design.

Description

Technical Field

[0001] The present invention relates to a method and system for pairing a user with an intelligent reflective surface to improve wireless transmission capacity, and belongs to the technical field of wireless communications. Background Art

[0002] A smart reflector is a reflective plane composed of a large number of low-cost passive reflective elements. It has the advantages of energy conservation, flexible deployment, and low-cost materials. Since each reflector unit can independently change the phase of the incident signal, smart reflectors can be used to assist wireless communication systems to improve system performance. In complex wireless communication networks, with the increasing shortage of spectrum resources, the increasing quality of wireless communication services required by users, and the promotion of green and energy-saving communications, the development of a new generation of wireless communications requires more technical support. Traditional communication theory believes that complex and time-varying wireless channels are uncontrollable. The emergence of smart reflectors has made it possible to artificially improve wireless channels. Therefore, the application prospects of smart reflectors are very broad, and research on them is increasing.

[0003] In future wireless communication networks, the envisioned use of smart reflectors is for large-scale deployment in buildings and other public facilities. Therefore, the question of how to pair smart reflectors with users becomes a pressing issue. Existing research assumes that the same smart reflector can serve multiple users simultaneously, so the design of its phase shift matrix must simultaneously account for information from multiple wireless channels, which complicates the design of the smart reflector's phase. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for pairing users with smart reflective surfaces to improve wireless transmission capacity, thereby improving wireless transmission capacity and reducing the complexity of smart reflective surface phase design.

[0005] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides a method for pairing a user with a smart reflective surface to improve wireless transmission capacity, comprising:

[0007] Acquire channel state information of direct links between the source node and each destination node and channel state information of cascade links between the source node and each destination node through each smart reflector surface;

[0008] Calculating a phase shift matrix of the smart reflection surface based on the channel state information of the direct link and the cascade link;

[0009] The channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector is calculated based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector;

[0010] The maximum value of the channel capacity is screened out by a maximum priority algorithm, and the user and smart reflective surface combination corresponding to the maximum value is the pairing result. The sum of the maximum values of the channel capacities corresponding to all users is the wireless transmission capacity;

[0011] Wherein, the destination node is a user.

[0012] In combination with the first aspect, further, the total link between the source node and each destination node with the assistance of each smart reflecting surface includes a direct link between the source node and each destination node and a cascade link between the source node and each destination node through each smart reflecting surface.

[0013] In combination with the first aspect, further, the cascade link between the source node and each destination node through each smart reflection surface is a Rice channel, and the modeling method of the Rice channel is as follows:

[0014] H l =h l L

[0015]

[0016]

[0017] Among them, l is 1 or 2. When l is 1, H l is the small-scale fading loss between the source node and each smart reflector. When l is 2, H l is the small-scale fading loss between each smart reflector and each destination node; h l is the Ricean channel gain, and L is the large-scale fading loss; K l is the Rice factor, is the complex Gaussian sight-distance component, and is the complex Gaussian non-line-of-sight component in the cascaded link, and d l is the distance from the source node to the smart reflective surface or to the destination node, α is the fading coefficient; S is the number of reflective elements on the smart reflective surface.

[0018] In combination with the first aspect, further, the direct link between the source node and each destination node is a Rayleigh channel, and the modeling method of the Rayleigh channel is as follows:

[0019]

[0020] Where L is the large-scale fading loss, is the complex Gaussian non-line-of-sight component in the direct link.

[0021] In combination with the first aspect, further, the smart reflective surface and the transmission signal are matched with an optimal phase shift, and the phase shift matrix of the optimal phase shift is calculated by the following method:

[0022] φ=diag(θ)

[0023] Where φ is the phase shift matrix, j is the imaginary unit, diag() is to take the elements of the corresponding vector to form a diagonal matrix, and T represents transpose.

[0024] In combination with the first aspect, further, the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflective surface is calculated by the following method:

[0025]

[0026] Among them, P is the transmission power of the transmission signal, H2 H φH1 represents the channel gain of the cascade link between the source node and the destination node with the assistance of the intelligent reflector, G represents the channel gain of the direct link between the source node and the destination node, |*| is the modulo operation, σ 2 is the noise power.

[0027] In combination with the first aspect, further, the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflective surface is calculated by the following method:

[0028]

[0029] Where P is the transmission power of the transmission signal, G represents the channel gain of the cascade link from the source node to the mth user with the assistance of the nth smart reflector. m represents the channel gain of the direct link between the source node and the mth user, |*| is the modulo operation, σ 2 is the noise power.

[0030] In combination with the first aspect, further, screening out the maximum value of the channel capacity by a maximum priority algorithm includes:

[0031] A: Store the channel capacity in an M×N CIM matrix, search for the largest element in the CIM matrix, record the value and position of the largest element, and set all elements in the same row and column to zero;

[0032] B: Repeat step A, ignoring all elements in the row and column of the largest element found. Find all the largest elements and record their values and positions until the rank of the CIM matrix reaches 0. This results in the maximum channel capacity for all users.

[0033] In the element positions, rows represent users and columns represent smart reflective surfaces; the value of the element represents the value of the channel capacity.

[0034] In a second aspect, the present invention further provides a user and smart reflective surface pairing system for improving wireless transmission capacity, comprising:

[0035] Channel state information acquisition module: used to obtain channel state information of direct links between the source node and each destination node and channel state information of cascade links between the source node and each destination node through each smart reflector surface;

[0036] Phase shift matrix calculation module: used to calculate the phase shift matrix of the smart reflection surface based on the channel state information of the direct link and the cascade link;

[0037] Channel capacity calculation module: used to calculate the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector;

[0038] Pairing module: used to filter out the maximum value of the channel capacity through the maximum priority algorithm. The user corresponding to the maximum value and the smart reflective surface combination are the pairing result, and the sum of the maximum values corresponding to all users is the wireless transmission capacity.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention provides a method and system for pairing users with intelligent reflective surfaces to improve wireless transmission capacity. The method calculates the channel capacity of the total link between a source node and each destination node, assisted by each intelligent reflective surface, based on channel state information of direct links and cascade links and the phase shift matrix of the intelligent reflective surface. The maximum value of the channel capacity is screened out using a maximum-first algorithm, thereby maximizing the wireless transmission capacity and improving the wireless transmission capacity. The user corresponding to the maximum value is combined with the intelligent reflective surface as the pairing result. The present invention considers that each intelligent reflective surface only serves one user, thereby increasing wireless transmission capacity, reducing the complexity of the intelligent reflective surface phase design, and improving pairing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a method for pairing a user with a smart reflective surface to improve wireless transmission capacity, provided by an embodiment of the present invention;

[0042] Figure 2 This is a system model of multi-user and multi-intelligent reflective surfaces provided by an embodiment of the present invention;

[0043] Figure 3 This is a comparison chart of wireless transmission capacities corresponding to different methods under different initial signal-to-noise ratios when the number of users is 5 and the number of smart reflective surfaces is 5, provided by an embodiment of the present invention;

[0044] Figure 4 This is a code example diagram of the maximum-first algorithm provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] Example 1

[0047] like Figure 2 As shown, a multi-user, multi-intelligent reflective surface system model is established, including a base station (source node), multiple users (destination nodes), and multiple intelligent reflective surfaces. All nodes in this system model can accurately obtain all link information. The source node sends the transmission signal to the destination node and the intelligent reflective surface. The intelligent reflective surface continuously controls the phase of the cascaded link to maintain consistency with the direct link, improving the signal strength reaching the destination node and thus increasing the wireless transmission capacity. The link between the source node and each destination node is a direct link, and the link between the source node and each destination node through each intelligent reflective surface is a cascaded link.

[0048] The source node sends signals in a time-division multiplexing manner, and all the above calculations are completed by the source node; multiple smart reflective surfaces are connected to a centralized controller.

[0049] like Figure 1 As shown, an embodiment of the present invention provides a method for pairing a user with a smart reflective surface to improve wireless transmission capacity, including:

[0050] The channel state information of the direct link between the source node and each destination node and the channel state information of the cascade link between the source node and each destination node through each smart reflective surface are obtained.

[0051] The channel state information between the source node and each destination node through each smart reflection surface is obtained. The channel state information includes the distance between each smart reflection surface and each destination node and the large-scale fading coefficient.

[0052] The channel characteristics between the source node and each destination node through each intelligent reflector surface follow the Rice distribution, which is modeled as follows:

[0053]

[0054] The modeling method of the path loss of each link is as follows:

[0055]

[0056] The modeling method of the overall modeling of the cascade link is as follows:

[0057] H l =h l L

[0058] Among them, l is 1 or 2. When l is 1, H l is the small-scale fading loss between the source node and each smart reflector. When l is 2, H l is the small-scale fading loss between each smart reflector and each destination node; h l is the Ricean channel gain, and L is the large-scale fading loss; K l is the Rice factor, is the complex Gaussian sight-distance component, and is the complex Gaussian non-line-of-sight component in the cascaded link, and d l is the distance from the source node to the smart reflective surface or to the destination node, α is the fading coefficient; S is the number of reflective elements on the smart reflective surface.

[0059] The direct link between the source node and each destination node is a Rayleigh channel, and the modeling method of the Rayleigh channel is as follows:

[0060]

[0061] Where L is the large-scale fading loss, is the complex Gaussian non-line-of-sight component in the direct link.

[0062] The phase shift matrix of the smart reflection surface is calculated according to the channel state information of the direct link and the cascade link.

[0063] The smart reflector and the transmitted signal are matched with an optimal phase shift. The phase shift matrix of the optimal phase shift is calculated by the following method:

[0064] φ=diag(θ)

[0065] Where φ is the phase shift matrix, j is the imaginary unit, diag() is to take the elements of the corresponding vector to form a diagonal matrix, and T represents transpose.

[0066] Since |a+b|≤|a|+|b|, |H2 is satisfied if and only if a and b are in phase. H φH1+G| is the largest. Therefore, the following formula is required:

[0067] angle(H2 H φH1)=angle(G)

[0068] And because:

[0069] H2 H φH1=θ T diag(H2 H )H1

[0070] make So:

[0071]

[0072] In this way, the optimal phase shift matrix φ can be calculated; where θ T is the transpose of θ, H2 H is the conjugate transpose of H2, angle is the phase operation; H1 is the small-scale fading loss between the source node and each smart reflector, and H2 is the small-scale fading loss between each smart reflector and each destination node.

[0073] The channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector is calculated based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector.

[0074] The channel capacity of the total link between the source node and each destination node with the assistance of each intelligent reflector is calculated using the following method:

[0075]

[0076] Among them, P is the transmission power of the transmission signal, H2 H φH1 represents the channel gain of the cascade link between the source node and the destination node with the assistance of the intelligent reflector, G represents the channel gain of the direct link between the source node and the destination node, |*| is the modulo operation, σ 2 is the noise power; H1 is the small-scale fading loss between the source node and each smart reflector; H2 is the small-scale fading loss between each smart reflector and each destination node.

[0077] When the number of users is M and the number of smart reflective surfaces is N, the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflective surface is calculated as follows:

[0078]

[0079] Where P is the transmission power of the transmission signal, G represents the channel gain of the cascade link from the source node to the mth user with the assistance of the nth smart reflector. m represents the channel gain of the direct link between the source node and the mth user, |*| is the modulo operation, σ 2 is the noise power; m is an integer from 1 to M, and n is an integer from 1 to N.

[0080] The maximum value of the channel capacity is screened out through the maximum priority algorithm, and the user corresponding to the maximum value and the smart reflective surface combination are the pairing result. The sum of the maximum values of the channel capacity corresponding to all users is the wireless transmission capacity.

[0081] Through Figure 4 The maximum priority algorithm shown in the figure selects the maximum channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector surface. The user and smart reflector surface combination corresponding to this maximum value is the pairing result. Where min(N,M) is the minimum number of users or smart reflectors, the CIM matrix is the matrix storing the channel capacity, max(CIM) is to find the maximum element in the CIM matrix, CIM(,m) = 0 and CIM(n,) = 0 means that the information of the paired user and smart reflector surface is ignored, and RIS is the smart reflector surface.

[0082] The maximum priority algorithm places the calculated channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector in the CIM matrix, where the rows and columns represent users and smart reflectors.

[0083] The algorithm process is to search for the largest element in the CIM matrix each time, and record the value and position information of the element. In the next search, all values in the row and column where the element is located are ignored, and the search is carried out in sequence until the rank of the CIM matrix is 0.

[0084] When recording element values and positions, if the number of users is less than the number of smart reflective surfaces, this algorithm ensures that each user is assisted by a smart reflective surface. If the number of users is greater than the number of smart reflective surfaces, the remaining users are not assigned smart reflective surfaces and communicate directly with the base station. However, after pairing is complete, the remaining user information cannot be determined. Therefore, the CIM matrix is multiplied by an N×1 matrix with all elements set to 1. The output is an M×1 matrix. The non-zero elements in this matrix are selected. The position of these elements corresponds to the remaining users without matching smart reflective surfaces. The channel capacity for these users becomes the channel capacity for direct link communication.

[0085] When the number of users is less than or equal to the number of smart reflective surfaces, this method can allocate a corresponding smart reflective surface to each user; when the number of users is greater than the number of smart reflective surfaces, the remaining users are not allocated smart reflective surfaces and communicate directly with the base station.

[0086] In actual operation, the calculated R m,n Store an M×N CIM matrix (CIM is a self-named name), then find the largest element in the matrix, record the position of the element and set all elements in the same row and column to zero.

[0087] However, if the number of users exceeds the number of smart reflective surfaces, the remaining user information cannot be determined after pairing is complete. Therefore, after the pairing is completed, the CIM matrix is multiplied by an N×1 matrix with all elements set to 1. The output is an M×1 matrix, and the non-zero elements in this matrix are selected. The position of this element corresponds to the remaining users without a matching smart reflective surface. The channel capacity of these users becomes the channel capacity for direct link communication.

[0088] The maximum-first algorithm selects pairing results, focusing on the maximum value of the elements in the matrix. This may sacrifice the wireless transmission capacity obtained through pairing. However, due to the random arrangement of spatial positions, the channel capacity of some users assisted by a certain smart reflector surface will be much greater than the channel capacity of others. Therefore, the wireless transmission capacity calculated by the pairing method provided by the present invention in this scenario is very close to the maximum wireless transmission capacity calculated by pairing using the Kuhn-Munkres algorithm.

[0089] The calculated pairing results are sent to a centralized controller connected to all smart reflective surfaces. The transmitter encodes each user's transmission signal and transmits it using time-division multiplexing. During each user's transmission time slot, the centralized controller activates the smart reflective surface corresponding to the matching result and adjusts its phase shift. Due to the differences in each user's channel, the phase shift matrix minimizes the amount of signal received from other users, thus negligible interference between user transmission signals.

[0090] The centralized controller can not only change the phase shift of the smart reflective surface, but also change the reflection amplitude of the smart reflective surface. When the reflection amplitude of the smart reflective surface is set to 0, it is equivalent to turning the smart reflective surface off. When the reflection amplitude of the smart reflective surface is set to 1, it is equivalent to turning the smart reflective surface on. The encoding order of each user transmission signal by the source node corresponds to the activation order of each smart reflective surface. Therefore, in fact, the source node only needs to send the transmission order information and phase shift information of the user transmission signal to the centralized controller.

[0091] A comparative solution and a method for pairing users with smart reflective surfaces to improve wireless transmission capacity provided by the present invention are given below for comparative analysis.

[0092] The Kuhn-Munkres algorithm divides users and smart reflective surfaces into two unrelated sets. During initialization, a weight is assigned to each element in the user set, which is equal to the maximum channel capacity of this user with the assistance of the smart reflective surface. During initialization, a weight is also assigned to each element in the smart reflective surface set, which is 0.

[0093] The next step is to search for each element of the user set to find the sum of the user's weight and the weight of a certain smart reflective surface equal to the maximum channel capacity of the user with the assistance of the smart reflective surface. At this time, the corresponding smart reflective surface I1 is the matching object for user U1.

[0094] However, when another user U2 finds the same smart reflective surface I1 at the same time, an augmenting path is formed. By searching along I1, U1 can be found. At this time, the weights of user U1 and smart reflective surface I1 need to be changed. The weight change strategy is:

[0095] First, calculate the minimum difference G1 between the channel capacity of user U1 without the assistance of smart reflector I1 and the channel capacity with the assistance of smart reflector I1. Next, calculate the minimum difference G2 between the channel capacity of user U2 without the assistance of smart reflector I1 and the channel capacity with the assistance of smart reflector I1. Then compare G1 and G2 and select the smaller one. If it is G1, reduce the weights of all users in the augmenting path by G1 and increase the weights of all smart reflectors in the augmenting path by G1. At this point, the weights of all elements in this augmenting path are changed. The purpose of changing the weights is to enable U1 and U2 to find a matching smart reflector and to ensure that the sum of the channel capacities of U1 and U2 in this augmenting path with the assistance of smart reflectors is maximized.

[0096] By repeatedly recursively applying the above algorithm and continuously changing the weights, a matching result is finally obtained. At this point, the channel capacity is maximized, that is, the wireless transmission capacity is maximized. When the number of users and smart reflective surfaces is equal, the matching result obtained by the Kuhn-Munkres algorithm is also called a perfect match. Each user can be matched with a smart reflective surface, and the wireless transmission capacity is maximized. When the number of users and smart reflective surfaces is not equal, it is necessary to artificially add fake users. The channel capacity of each fake user communicating through the smart reflective surface is zero. In other words, the CIM matrix is padded with zeros to form a square matrix. In the result, any matching result with a channel capacity of zero is considered invalid.

[0097] In order to test the effect of the present invention, a simulation experiment was carried out using MATLAB.

[0098] The simulation assumes that all devices in the system know the channel state information, the base station can send multiple signals simultaneously, and the interference between smart reflective surfaces is ignored. Because the smart reflective surfaces have the effect of beamforming, the interference between users is ignored, and the time for designing the phase shift matrix of the smart reflective surfaces is ignored. The simulation tests the wireless transmission capacity of the method of the present invention, the matching method using the Kuhn-Munkres algorithm, and the random matching method under different initial signal-to-noise ratios.

[0099] The channel capacity under each signal-to-noise ratio is obtained using the Monte Carlo algorithm to meet the universality of the experiment; the simulation parameters are: the number of smart reflective surfaces is 5, the number of channel simulations is 500, there are 64 reflective elements on each smart reflective surface, and the number of users is 5; the initial signal-to-noise ratio is 23dB to 35dB, each group of data is 3dB apart, there are five groups in total, and the path loss index α is 3; the distances between the user, the smart reflective surface and the base station are all random. Since the closer the smart reflective surface is to the transmitter or receiver, the better its effect, considering the actual application scenario, the distance between the simulated smart reflective surface and the user is relatively close; the simulation results of MATLAB are as follows Figure 3 shown.

[0100] exist Figure 3 The wireless transmission capacity obtained by pairing using the Kuhn-Munkres algorithm is slightly better than the pairing method of the present invention, but this method requires recursion and search, and the algorithm logic is relatively complex, with a complexity of O(v 3 ), where v = max(M, N), and the complexity of the algorithm of the present invention is O(z 2 ), where z = min(M, N); therefore, the present invention provides a method for pairing users with intelligent reflective surfaces for improving wireless transmission capacity, which reduces the complexity of the algorithm logic while maintaining a large wireless transmission capacity.

[0101] Example 2

[0102] An embodiment of the present invention provides a user and smart reflective surface pairing system for improving wireless transmission capacity, including:

[0103] Channel state information acquisition module: used to obtain channel state information of direct links between the source node and each destination node and channel state information of cascade links between the source node and each destination node through each smart reflector surface;

[0104] Phase shift matrix calculation module: used to calculate the phase shift matrix of the smart reflection surface based on the channel state information of the direct link and the cascade link;

[0105] Channel capacity calculation module: used to calculate the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector;

[0106] Pairing module: used to filter out the maximum value of the channel capacity through the maximum priority algorithm. The user corresponding to the maximum value and the smart reflective surface combination are the pairing result, and the sum of the maximum values corresponding to all users is the wireless transmission capacity.

[0107] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0108] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0111] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for pairing users with smart reflective surfaces to improve wireless transmission capacity, characterized in that: include: Acquire channel state information of direct links between the source node and each destination node and channel state information of cascade links between the source node and each destination node through each smart reflector surface; Calculating a phase shift matrix of the smart reflection surface based on the channel state information of the direct link and the cascade link; The channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector is calculated based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector; The maximum value of the channel capacity is screened out by a maximum priority algorithm, and the user and smart reflective surface combination corresponding to the maximum value is the pairing result. The sum of the maximum values of the channel capacity corresponding to all users is the wireless transmission capacity, where the destination node is the user; The step of screening out the maximum value of the channel capacity by using a maximum value first algorithm includes: A: Store the channel capacity in an M×N CIM matrix, which is the channel information matrix. Search for the largest element in the CIM matrix, record the value and position of the largest element, and set all elements in the same row and column to zero. B: Repeat step A, ignoring all elements in the row and column of the largest element found. Find all the largest elements and record their values and positions until the rank of the CIM matrix reaches 0. This results in the maximum channel capacity for all users. In the position of the elements, the rows represent users and the columns represent smart reflective surfaces; the values of the elements represent the channel capacity values; When recording element values and positions, if the number of users exceeds the number of smart reflectors, after pairing, the CIM matrix is multiplied by an N×1 matrix whose elements are all 1. The output is an M×1 matrix, and the non-zero elements in this matrix are selected. The positions of these elements correspond to the remaining users without matching smart reflectors. The channel capacity for these users becomes the channel capacity for direct link communication.

2. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The total link between the source node and each destination node with the assistance of each intelligent reflecting surface includes a direct link between the source node and each destination node and a cascade link between the source node and each destination node through each intelligent reflecting surface.

3. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The cascade link between the source node and each destination node through each intelligent reflection surface is a Rice channel, and the modeling method of the Rice channel is as follows: H l h l L Among them, l is 1 or 2. When l is 1, H l is the small-scale fading coefficient matrix between the source node and each smart reflector. When l is 2, H l h is the small-scale fading coefficient matrix between each intelligent reflector and each destination node; l is the Ricean channel gain, and L is the large-scale fading loss; K l is the Rice factor, is the complex Gaussian sight-distance component, and is the complex Gaussian non-line-of-sight component in the cascaded link, and d l is the distance from the source node to the intelligent reflector or to the destination node, in d l In the equation (1), when l = 1, it represents the distance from the source node to the smart reflective surface; when l = 2, it represents the distance from the source node to the destination node; α is the fading coefficient; and S is the number of reflective elements on the smart reflective surface.

4. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The direct link between the source node and each destination node is a Rayleigh channel, and the modeling method of the Rayleigh channel is as follows: Where L is the large-scale fading loss, is the complex Gaussian non-line-of-sight component in the direct link.

5. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The smart reflective surface is matched with the transmission signal with an optimal phase shift, and the phase shift matrix of the optimal phase shift is calculated by the following method: φ=diag(θ) Where φ is the phase shift matrix, j is the imaginary unit, diag() is to take the elements of the corresponding vector to form a diagonal matrix, T represents the transpose, θ1 to θ S They respectively represent the phase values of the 1st to Sth reflection units of the smart reflection surface.

6. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The channel capacity of the total link between the source node and each destination node with the assistance of each intelligent reflector is calculated using the following method: Among them, P is the transmission power of the transmission signal, H2 H φH1 represents the channel gain of the cascade link between the source node and the destination node with the assistance of the intelligent reflector, G represents the channel gain of the direct link between the source node and the destination node, |*| is the modulo operation, σ 2 is the noise power, H2 represents the small-scale fading coefficient matrix between each smart reflector and each destination node, H represents the conjugate transpose, φ represents the phase shift matrix of the smart reflector, and H1 represents the small-scale fading coefficient matrix between the source node and each smart reflector.

7. The method for pairing users with smart reflective surfaces to improve wireless transmission capacity according to claim 1, characterized in that: The channel capacity of the total link between the source node and each destination node with the assistance of each intelligent reflector is calculated using the following method: Where P is the transmission power of the transmission signal, G represents the channel gain of the cascade link from the source node to the mth user with the assistance of the nth smart reflector. m represents the channel gain of the direct link between the source node and the mth user, |*| is the modulo operation, σ 2 is the noise power, Represents the element in the mth row and nth column of the small-scale fading coefficient matrix H1 between the source node and each smart reflector surface, represents the element in the mth row and nth column of the small-scale fading coefficient matrix H2 between each smart reflector and each destination node, φ m,n Represents the element in the mth row and nth column of the phase shift matrix of the smart reflector.

8. A user and smart reflective surface pairing system for improving wireless transmission capacity, characterized in that: include: Channel state information acquisition module: used to obtain channel state information of direct links between the source node and each destination node and channel state information of cascade links between the source node and each destination node through each smart reflector surface; Phase shift matrix calculation module: used to calculate the phase shift matrix of the smart reflection surface based on the channel state information of the direct link and the cascade link; Channel capacity calculation module: used to calculate the channel capacity of the total link between the source node and each destination node with the assistance of each smart reflector based on the channel state information of the direct link and the cascade link and the phase shift matrix of the smart reflector; Pairing module: used to filter out the maximum value of the channel capacity through the maximum priority algorithm. The user corresponding to the maximum value and the smart reflective surface combination are the pairing result. The sum of the maximum values corresponding to all users is the wireless transmission capacity; The step of filtering out the maximum value of the channel capacity by using a maximum priority algorithm includes: A: Store the channel capacity in an M×N CIM matrix, which is the channel information matrix. Search for the largest element in the CIM matrix, record the value and position of the largest element, and set all elements in the same row and column to zero. B: Repeat step A, ignoring all elements in the row and column of the largest element found. Find all the largest elements and record their values and positions until the rank of the CIM matrix reaches 0. This results in the maximum channel capacity for all users. In the position of the elements, the rows represent users and the columns represent smart reflective surfaces; the values of the elements represent the channel capacity values; When recording element values and positions, if the number of users exceeds the number of smart reflectors, after pairing, the CIM matrix is multiplied by an N×1 matrix whose elements are all 1. The output is an M×1 matrix, and the non-zero elements in this matrix are selected. The positions of these elements correspond to the remaining users without matching smart reflectors. The channel capacity for these users becomes the channel capacity for direct link communication.

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