User scheduling and transmission method for intelligent metasurface assisted uplink communication system

Abstract

The application discloses a user scheduling and transmission method of an intelligent metasurface assisted uplink communication system, and belongs to the wireless communication field. A cell base station adopts a uniform linear antenna array, and an intelligent metasurface adopts a uniform plane array. There are a plurality of single-antenna users at the edge of the cell, which cannot be covered by the base station signal of the cell, and need to be served by providing services. The base station schedules a part of the users from the users to serve. The specific steps are as follows: reasonably deploying the positions of the intelligent metasurface and the base station, scheduling a user group with small channel correlation by using statistical channel information of the users, selecting a discrete Fourier transform code word by the intelligent metasurface by using statistical channel state information of the scheduled user group, and adopting a zero-forcing linear receiver at the base station. The application can perform user scheduling and transmission design with low calculation complexity, can effectively reduce the inter-user interference, and can obtain high system throughput, and is easy to implement.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a user scheduling and transmission method for an intelligent metasurface-assisted uplink communication system. Background Technology

[0002] With the rapid growth in the number of mobile users and wireless devices, the scale and demands of communication networks are expanding, and existing fifth-generation (5G) communication technology can no longer fully meet these needs. To satisfy the multiple demands of future mobile communication networks, such as high capacity, low latency, and energy efficiency, new breakthroughs are needed in basic transmission technologies and resource utilization. Intelligent metasurfaces (RIS), which have emerged in recent years, have become a highly promising technology for 5G and even 6G communication due to their low manufacturing cost, low energy consumption, and reconfigurability. By densely deploying intelligent metasurfaces (RIS) in wireless networks and cleverly coordinating their reflections, the wireless channel between transmitters and receivers can be flexibly reconfigured, thereby reducing wireless channel fading and interference problems.

[0003] When instantaneous Channel State Information (CSI) is known, user scheduling algorithms, the reflection coefficient matrix of the smart metasurface, and the linear receiver at the base station can be jointly designed. However, due to the passive structure of the smart metasurface, user mobility, and the large number of users, obtaining accurate instantaneous CSI is extremely challenging, resulting in high signal processing complexity and significant training overhead. Summary of the Invention

[0004] This invention provides a user scheduling and transmission method for an intelligent metasurface-assisted uplink communication system. Based on the dual-time-scale principle, it employs statistical CSI to design user scheduling criteria and the intelligent metasurface reflection coefficient matrix, and designs the base station linear receiver based on instantaneous CSI. User scheduling is based on the correlation between user statistical channels, and the intelligent metasurface phase shift design is based on the statistical CSI of the scheduled users.

[0005] A first aspect of the present invention provides a user scheduling and transmission method for a smart metasurface-assisted uplink communication system, used to configure a single uplink communication system for a cell with R blocks of smart metasurfaces, wherein there are K single-antenna users in the cell that cannot be covered by the base station signal, the base station adopts a uniform linear antenna array with M antenna elements, and the smart metasurface adopts a uniform planar array containing N reflective elements. The method includes the following steps:

[0006] In the single uplink communication system of the cell, smart metasurface locations are deployed such that the response vector between any two smart metasurfaces satisfies in, and Let represent the angle of arrival of the line-of-sight path between the j1-th and j2-th smart metasurfaces and the base station, respectively, where j1 = 1, ..., R, j2 = 1, ..., R, d is the spacing between adjacent antenna elements on the antenna array of base station k, λ is the carrier wavelength, and M is the number of antenna elements in each cell base station array. The superscript (·) H Represents conjugate transpose;

[0007] Users are grouped according to the distance between each smart metasurface and each user, and user scheduling is performed using the statistical channel state information between each smart metasurface and each user.

[0008] The phase shift design of the smart metasurface is carried out by utilizing the statistical channel state information between the cell base station and each smart metasurface, as well as between each smart metasurface and each user. The design of the base station linear receiver is carried out by utilizing the equivalent instantaneous channel state information between the scheduled users and the base station.

[0009] Optionally, in one embodiment of the present invention, the statistical channel state information includes: the vertical wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The horizontal wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is separated by the wave departure angle in the vertical direction of the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is relative to the horizontal wave departure angle of the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is relative to the wave angle of arrival at the base station. Rice factor β of the link from the j-th smart metasurface to the base station j j = 1, ..., R;

[0010] The equivalent instantaneous channel state information includes: the equivalent instantaneous channel information h from user k to the base station. k .

[0011] Optionally, in one embodiment of the present invention, user grouping is performed based on the distance between each smart metasurface and each user, including:

[0012] a1) For each intelligent metasurface j, put all users into the allocatable user set Λ j ;

[0013] a2) Initialize the service user candidate set for each smart metasurface Initialize the number of alternating assignment rounds t = 1;

[0014] a3) In the t-th round of allocation, initialize the smart metasurface index n = 1 for the current user to be allocated;

[0015] a4) represents the nth intelligent metasurface from the allocatable user set Λ n Select the nearest user τ n Update the service user candidate set Π of the intelligent metasurface n n =Π n ∪{τ n}, update the set of allocatable users for each smart metasurface to Λ j =Λ j \{τ n},j=1,…,R, update the smart metasurface index n=n+1 for the current user to be assigned;

[0016] a5) Repeat step a4) until n = R + 1 or Stop when the time is right, update the alternation allocation round number t = t + 1, and jump to step a3) when t ≤ K / R, otherwise stop.

[0017] Optionally, in one embodiment of the present invention, user scheduling is performed using statistical channel state information between each smart metasurface and each user, employing a greedy minimum-maximum correlation user scheduling algorithm, including:

[0018] b1) Initialize the system's already scheduled user set Initialize the system to have 0 scheduled users (s = 0).

[0019] b2) Randomly schedule a service user π1 for intelligent metasurface 1 from the candidate user set Π1, update the system's scheduled user set Ξ=Ξ∪{π1}, and update the system's scheduled user count s=1;

[0020] b3) Let j = s + 1, initialize the candidate set of service users for the j-th intelligent metasurface Π j Users k = 1, ..., K j The maximum correlation is ρ k,j =0,K j Represents set Π j The number of users in the set Π j Each user k, k = 1, ..., K j Calculate its maximum correlation ρ k,j :

[0021]

[0022] Where l is the sequence number of the scheduled smart metasurface, π l This represents the service user scheduled by the l-th intelligent metasurface. This represents the line-of-sight component from the l-th smart metasurface to the j-th smart metasurface. This represents the line-of-sight component from the l-th intelligent metasurface to the service user scheduled by the l-th intelligent metasurface. This represents the view distance component from user k to the j-th smart metasurface. The vector represents the view distance component from user k to the l-th smart metasurface. and Let η represent the large-scale fading coefficients from the service user scheduled to the l-th smart metasurface to the j-th and l-th smart metasurfaces, respectively. k,j and η k,l Let d represent the large-scale fading coefficients from user k to the j-th and l-th smart metasurfaces, respectively. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents the Kronecker product, superscript (·). H Represents conjugate transpose;

[0023] b4) Schedule the service users of the j-th intelligent metasurface block to its candidate user set Π j The user with the lowest maximum relevance:

[0024]

[0025] b5) Update the system's scheduled user set to Ξ=Ξ∪{π} j The number of users already scheduled by the system is updated to s = s + 1.

[0026] b6) Repeat steps b3) to b5) until s = R + 1.

[0027] Optionally, in one embodiment of the present invention, the phase shift design of the smart metasurface is performed using statistical channel state information between the cell base station and each smart metasurface, and between each smart metasurface and each user, including:

[0028] c1) Generate an N-dimensional discrete Fourier codebook C = {c 1,1 ,...,c 1,v ,...,c h,1 ,...,c h,v}, where code words

[0029] c2) Select the optimal γ discrete Fourier transform candidate codewords for the j-th smart metasurface:

[0030]

[0031] in, Let the vector represent the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. η k,j d represents the large-scale fading coefficient of the link from the service user scheduled to the j-th smart metasurface. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents Kronecker;

[0032] c3) Combine the discrete Fourier transform candidate codewords of the R-block intelligent metasurface to obtain the quantity set γ. R Discrete Fourier Transform Candidate Codeword Combinations With the goal of maximizing and approximately traversing the spectral efficiency, the optimal discrete Fourier transform codeword combination is selected:

[0033]

[0034] in, Describe the optimal discrete Fourier transform codeword of the intelligent metasurface j. To schedule user π i The approximate ergodic efficiency is expressed as:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] Where p is the transmission power of each user, ξ j β represents the fading coefficient of the link from the smart metasurface j to the base station. j Represents the Rice factor of the smart metasurface j-to-base station link. This represents the line-of-sight component from the smart metasurface j to the base station. This represents the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. Let represent the large-scale fading coefficient of the link from the service user scheduled to the j-th intelligent metasurface, [·]. k This indicates the deletion of the k-th column of the matrix, and ψ(·) represents the digamma function operation;

[0041] c4) Set the reflection coefficient matrix of the j-th smart metasurface to...

[0042] Optionally, in one embodiment of the present invention, the design of a base station linear receiver is performed using the equivalent instantaneous channel state information between the scheduled user and the base station, including:

[0043] The base station linear receiver is designed as a zero-forcing receiver, wherein the zero-forcing receiver is:

[0044] W ZF =(H H H) -1 H H

[0045] Where H = [h1, h2, ..., h R ] represents the joint channel matrix of R scheduled users, h k This represents the equivalent instantaneous channel vector between the k-th scheduling user and the base station.

[0046] The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to the embodiments of the present invention has the following beneficial effects:

[0047] (1) This invention is applicable to a single-cell uplink communication system assisted by multiple IRS blocks, and a low-complexity user scheduling algorithm and adaptive transmission method are designed based on dual time scales.

[0048] (2) The user scheduling algorithm involved in this invention uses statistical channel information, which reduces the overhead of acquiring channel information;

[0049] (3) The calculation of the IRS phase shift involved in this invention does not require search iteration, has lower computational complexity than existing algorithms, and is easy to implement.

[0050] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0051] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0052] Figure 1 This is a flowchart illustrating a user scheduling and transmission method for an intelligent metasurface-assisted uplink communication system according to an embodiment of the present invention. Detailed Implementation

[0053] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0054] As mentioned in the background, due to the passive structure of smart metasurfaces, user mobility, and the large number of users, obtaining accurate instantaneous CSI is extremely challenging, leading to high signal processing complexity and significant training overhead. In contrast, the statistical CSI of the channel remains unchanged over a long period, requiring less training overhead. Considering a dual-timescale principle, using statistical CSI to design user scheduling algorithms and smart metasurface phase shifting, and using instantaneous CSI to design linear receivers at the base station, the channel acquisition overhead can be significantly reduced.

[0055] Because a cell contains multiple users and multiple RIS (Relationship Assisted Systems), jointly scheduling users and designing phase shifters for multiple intelligent metasurfaces is more complex than in the case of fixed users. Designing reasonable user scheduling criteria and intelligent metasurface phase shift matrix calculation methods can effectively reduce inter-user interference and lower the complexity of user scheduling and intelligent metasurface phase shift design. In summary, for a single-cell uplink communication system assisted by intelligent metasurfaces, based on the dual-timescale principle, statistical CSI is used to design the user scheduling algorithm and intelligent metasurface phase shifters, while instantaneous CSI is used to design the linear receiver at the base station.

[0056] Figure 1 This is a flowchart illustrating a user scheduling and transmission method for an intelligent metasurface-assisted uplink communication system according to an embodiment of the present invention.

[0057] The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system is applicable to a single-cell uplink communication system with multiple intelligent metasurfaces. R intelligent metasurfaces are deployed at the edge of the cell. There are K single-antenna users at the cell edge that cannot be covered by the base station signal and need to transmit signals to them through the intelligent metasurfaces. The cell base station adopts a uniform linear antenna array containing M antenna elements. Each intelligent metasurface adopts a uniform planar array containing N reflection elements, with h rows of reflection elements in the vertical direction and v reflection elements in each row in the horizontal direction.

[0058] like Figure 1 As shown, the user scheduling and transmission method of this intelligent metasurface-assisted uplink communication system includes the following steps:

[0059] In step S101, the positions of the smart metasurfaces are rationally deployed such that the response vector between any two smart metasurfaces satisfies the following condition:

[0060]

[0061] in, and Let represent the angle of arrival of the line-of-sight path between the j1-th and j2-th smart metasurfaces and the base station, respectively, where j1 = 1, ..., R, j2 = 1, ..., R, d is the spacing between adjacent antenna elements on the antenna array of base station k, λ is the carrier wavelength, and M is the number of antenna elements in each cell base station array. The superscript (·) H This represents the conjugate transpose.

[0062] In step S102, users are grouped using the distance between each smart metasurface and each user, and users are scheduled using the statistical channel state information between each smart metasurface and each user.

[0063] In embodiments of the present invention, the required statistical channel state information includes: the vertical wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The horizontal wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is separated by the wave departure angle in the vertical direction of the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is relative to the horizontal wave departure angle of the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is relative to the wave angle of arrival at the base station. Rice factor β of the link from the j-th smart metasurface to the base station j j = 1, ..., R

[0064] In an embodiment of the present invention, user grouping is performed using the distance between each smart metasurface and each user, specifically including the following sub-steps:

[0065] a1) For each intelligent metasurface j, put all users into the allocatable user set Λ j ;

[0066] a2) Initialize the service user candidate set for each smart metasurface Initialize the number of alternating assignment rounds t = 1;

[0067] a3) In the t-th round of allocation, initialize the smart metasurface index n = 1 for the current user to be allocated;

[0068] a4) represents the nth intelligent metasurface from the allocatable user set Λ n Select the nearest user τ n Update the service user candidate set Π of the intelligent metasurface n n =Π n ∪{τ n}, update the set of allocatable users for each smart metasurface to Λ j =Λ j\{τ n},j=1,…,R, update the smart metasurface index n=n+1 for the current user to be assigned;

[0069] a5) Repeat step a4) until n = R + 1 or Stop when the time is right, update the alternation allocation round number t = t + 1, and jump to step a3) when t ≤ K / R, otherwise stop.

[0070] In embodiments of the present invention, a minimum-maximum correlation user scheduling algorithm based on a greedy approach is employed, specifically including the following sub-steps:

[0071] b1) Initialize the system's already scheduled user set Initialize the system to have 0 scheduled users (s = 0).

[0072] b2) Randomly schedule a service user π1 for intelligent metasurface 1 from the candidate user set Π1, update the system's scheduled user set Ξ=Ξ∪{π1}, and update the system's scheduled user count s=1;

[0073] b3) Let j = s + 1, initialize the candidate set of service users for the j-th intelligent metasurface Π j Users k = 1, ..., K j The maximum correlation is ρ k,j =0,K j Represents set Π j The number of users in the set Π j Each user k, k = 1, ..., K j Calculate its maximum correlation ρ k,j :

[0074]

[0075] Where l is the sequence number of the scheduled smart metasurface, π l This represents the service user scheduled by the l-th intelligent metasurface. This represents the line-of-sight component from the l-th smart metasurface to the j-th smart metasurface. This represents the line-of-sight component from the l-th intelligent metasurface to the service user scheduled by the l-th intelligent metasurface. This represents the view distance component from user k to the j-th smart metasurface. The vector represents the view distance component from user k to the l-th smart metasurface. and Let η represent the large-scale fading coefficients from the service user scheduled to the l-th smart metasurface to the j-th and l-th smart metasurfaces, respectively. k,j and η k,lLet d represent the large-scale fading coefficients from user k to the j-th and l-th smart metasurfaces, respectively. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents the Kronecker product, superscript (·). H Represents conjugate transpose;

[0076] b4) Schedule the service users of the j-th intelligent metasurface block to its candidate user set Π j The user with the lowest maximum relevance:

[0077]

[0078] b5) Update the system's scheduled user set to Ξ=Ξ∪{π} j The number of users already scheduled by the system is updated to s = s + 1.

[0079] b6) Repeat steps b3) to b5) until s = R + 1.

[0080] In step S103, the phase shift design of the smart metasurface is carried out using the statistical channel state information between the cell base station and each smart metasurface, and between each smart metasurface and each scheduling user. The design of the base station linear receiver is carried out using the equivalent instantaneous channel state information between the scheduling user and the base station.

[0081] In embodiments of the present invention, the required equivalent instantaneous channel state information includes: the equivalent instantaneous channel information h from user k to the base station. k .

[0082] In an embodiment of the present invention, the intelligent metasurface phase-shifting design selects DFT codewords with the goal of maximizing the useful signal for serving users. Specific steps include:

[0083] c1) Generate an N-dimensional discrete Fourier codebook C = {c 1,1 ,...,c 1,v ,...,c h,1 ,...,c h,v}, where code words

[0084] c2) Select the optimal γ DFT candidate codewords for the j-th smart metasurface, i.e.

[0085]

[0086] in, Let the vector represent the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. η k,jd represents the large-scale fading coefficient of the link from the service user scheduled to the j-th smart metasurface. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents Kronecker;

[0087] c3) Combining the DFT candidate codewords of these R smart metasurfaces yields a quantity set of γ. R DFT candidate codeword combination set The goal is to maximize and approximately traverse the spectral efficiency, selecting the optimal DFT codeword combination, i.e.

[0088]

[0089] in, This represents the optimal DFT codeword for smart metasurface j. To schedule user π i The approximate ergodic spectrum efficiency is expressed in the following form.

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Where p is the transmission power of each user, ξ j β represents the fading coefficient of the link from the smart metasurface j to the base station. j Represents the Rice factor of the smart metasurface j-to-base station link. This represents the line-of-sight component from the smart metasurface j to the base station. This represents the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. Let represent the large-scale fading coefficient of the link from the service user scheduled to the j-th intelligent metasurface, [·]. k This indicates the deletion of the k-th column of the matrix, and ψ(·) represents the digamma function operation;

[0096] c4) Finally, the reflection coefficient matrix of the j-th smart metasurface is set to

[0097] In an embodiment of the present invention, the base station linear receiver is designed using the equivalent instantaneous channel state information between the scheduling user and the base station. The base station linear receiver is designed as a zero-forcing receiver as follows:

[0098] W ZF =(H H H) -1 H H

[0099] Where H = [h1, h2, ..., h R ] represents the joint channel matrix of R scheduled users, h k This represents the equivalent instantaneous channel vector between the k-th scheduling user and the base station.

[0100] The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system of the present invention will be described below through a specific embodiment.

[0101] In a single-cell uplink communication system assisted by multiple smart metasurfaces, two smart metasurfaces are deployed at the cell edge. Twelve single-antenna users at the cell edge are not covered by the base station signal and require signal transmission through the smart metasurfaces. The cell base station uses a uniform linear antenna array with 32 antenna elements. Each smart metasurface uses a uniform planar array with 64 reflection elements, comprising 8 rows of reflection elements vertically and 8 reflection elements per row horizontally. The method includes the following steps:

[0102] The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system specifically includes the following steps:

[0103] Step 1: Deploy the smart metasurfaces appropriately so that the response vector between any two smart metasurfaces satisfies the following condition:

[0104]

[0105] in, and Let represent the angles of arrival of the line-of-sight paths between the j1-th and j2-th smart metasurfaces and the base station, respectively, where j1 = 1, 2 and j2 = 1, 2. d is the spacing between adjacent antenna elements on the antenna array of base station k, λ is the carrier wavelength, and M is the number of antenna elements in each cell base station array. The superscript (·) H This represents the conjugate transpose.

[0106] Step 2: Use the distance between each smart metasurface and each user to group users, and use the statistical channel state information between each smart metasurface and each user to schedule users.

[0107] Step 3: Use the statistical channel state information between the cell base station and each smart metasurface, and between each smart metasurface and each scheduling user, to design the phase shift of the smart metasurface. Use the equivalent instantaneous channel state information between the scheduling user and the base station to design the base station linear receiver.

[0108] Step two involves grouping users based on the distance between each smart metasurface and each user, specifically including the following sub-steps:

[0109] a1) For each intelligent metasurface j, place all users into its allocatable user set Λ j ;

[0110] a2) Initialize the service user candidate set for each smart metasurface Initialize the number of alternating assignment rounds t = 1;

[0111] a3) In the t-th round of allocation, initialize the smart metasurface index n = 1 for the current user to be allocated;

[0112] a4) represents the nth intelligent metasurface from the allocatable user set Λ n Select the user closest to it τ n Update the service user candidate set Π of the intelligent metasurface n n =Π n ∪{τ n}, update the set of allocatable users for each smart metasurface to Λ j =Λ j \{τ n},j=1,2, update the smart metasurface index n=n+1 for the current user to be assigned;

[0113] a5) Repeat step a4) until n = 3 or Stop when t is reached, update the alternation allocation round number t = t + 1, and jump to step a3 when t ≤ 6, otherwise stop.

[0114] The user scheduling in step two employs a minimum-maximum correlation user scheduling algorithm based on a greedy approach, specifically including the following sub-steps:

[0115] b1) Initialize the system's already scheduled user set Initialize the system to have 0 scheduled users (s = 0).

[0116] b2) Randomly schedule a service user π1 for intelligent metasurface 1 from the candidate user set Π1, update the system's scheduled user set Ξ=Ξ∪{π1}, and update the system's scheduled user count s=1;

[0117] b3) Let j = s + 1, initialize the candidate set of service users for the j-th intelligent metasurface Π jUsers k = 1, ..., K j The maximum correlation is ρ k,j =0,K j Represents set Π j The number of users in the set Π j Each user k, k = 1, ..., K j The maximum correlation ρ is calculated using the following formula. k,j :

[0118]

[0119] Where l is the sequence number of the scheduled smart metasurface, π l This represents the service user scheduled by the l-th intelligent metasurface. This represents the line-of-sight component from the l-th smart metasurface to the j-th smart metasurface. This represents the line-of-sight component from the l-th intelligent metasurface to the service user scheduled by the l-th intelligent metasurface. This represents the view distance component from user k to the j-th smart metasurface. The vector represents the view distance component from user k to the l-th smart metasurface. and Let η represent the large-scale fading coefficients from the service user scheduled to the l-th smart metasurface to the j-th and l-th smart metasurfaces, respectively. k,j and η k,l Let d represent the large-scale fading coefficients from user k to the j-th and l-th smart metasurfaces, respectively. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents the Kronecker product, superscript (·). H Represents conjugate transpose;

[0120] b4) Schedule the service users of the j-th intelligent metasurface block to its candidate user set Π j The user with the lowest maximum relevance, i.e.

[0121]

[0122] b5) Update the system's scheduled user set to Ξ=Ξ∪{π} j The number of users already scheduled by the system is updated to s = s + 1.

[0123] b6) Repeat steps b3) to b5) until s = 3.

[0124] The intelligent metasurface phase-shift design in step three aims to select DFT codewords with the goal of maximizing the useful signal for the user. Specific steps include:

[0125] c1) Generate an N-dimensional discrete Fourier codebook C = {c 1,1 ,...,c 1,v ,...,c h,1 ,...,c h,v}, where code words

[0126] c2) Select the four optimal DFT candidate codewords for the j-th smart metasurface, i.e.

[0127]

[0128] in, Let the vector represent the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. η k,j d represents the large-scale fading coefficient of the link from the service user scheduled to the j-th smart metasurface. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents Kronecker;

[0129] c3) Combining the DFT candidate codewords of these R smart metasurfaces yields a set of 4. 2 DFT candidate codeword combination set The goal is to maximize and approximately traverse the spectral efficiency, selecting the optimal DFT codeword combination, i.e.

[0130]

[0131] in, This represents the optimal DFT codeword for smart metasurface j. To schedule user π i The approximate ergodic efficiency is expressed in the following form:

[0132]

[0133]

[0134]

[0135]

[0136]

[0137] Where p is the transmission power of each user, ξ j β represents the fading coefficient of the link from the smart metasurface j to the base station. j Represents the Rice factor of the smart metasurface j-to-base station link. This represents the line-of-sight component from the smart metasurface j to the base station. This represents the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. Let represent the large-scale fading coefficient of the link from the service user scheduled to the j-th intelligent metasurface, [·]. k This indicates the deletion of the k-th column of the matrix, and ψ(·) represents the digamma function operation;

[0138] c4) Finally, the reflection coefficient matrix of the j-th smart metasurface is set to

[0139] The design of the base station linear receiver in step three utilizes the equivalent instantaneous channel state information between the scheduling user and the base station. The base station linear receiver is designed as a zero-forcing receiver as follows:

[0140] W ZF =(H H H) -1 H H

[0141] Where H = [h1, h2] represents the joint channel matrix of the scheduling users, h k This represents the equivalent instantaneous channel vector between the k-th scheduling user and the base station.

[0142] This invention discloses a user scheduling and transmission method for an intelligent metasurface-assisted uplink communication system. The cell base station employs a uniform linear antenna array, and the intelligent metasurface employs a uniform planar array. Several single-antenna users at the cell edge are not covered by the base station signal and require service provision. The base station schedules a subset of these users for service. Specifically, the intelligent metasurface and base station are strategically positioned. The statistical channel information of the users is used to schedule user groups with low channel correlation. The intelligent metasurface uses the statistical channel state information of the scheduled user groups to select discrete Fourier transform codewords. A zero-forcing linear receiver is used at the base station. This invention enables user scheduling and transmission design with low computational complexity, effectively reduces inter-user interference, and achieves high system throughput. It is also easy to implement.

[0143] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0144] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0145] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

Claims

1. A user scheduling and transmission method for a smart metasurface-assisted uplink communication system, used to configure a single-cell uplink communication system with R blocks of smart metasurfaces, wherein there are K single-antenna users in the cell that cannot be covered by the base station signal, the base station adopts a uniform linear antenna array with M antenna elements, and the smart metasurface adopts a uniform planar array containing N reflection elements, characterized in that, Includes the following steps: In the single uplink communication system of the cell, smart metasurface locations are deployed such that the response vector between any two smart metasurfaces satisfies in, and Let represent the angle of arrival of the line-of-sight path between the j1-th and j2-th smart metasurfaces and the base station, respectively, where j1 = 1, ..., R, j2 = 1, ..., R, d is the spacing between adjacent antenna elements on the antenna array of base station k, λ is the carrier wavelength, and M is the number of antenna elements in each cell base station array. The superscript (·) H Represents conjugate transpose; Users are grouped according to the distance between each smart metasurface and each user, and user scheduling is performed using the statistical channel state information between each smart metasurface and each user. The phase shift design of the smart metasurface is carried out by utilizing the statistical channel state information between the cell base station and each smart metasurface, as well as between each smart metasurface and each user. The design of the base station linear receiver is carried out by utilizing the equivalent instantaneous channel state information between the scheduled users and the base station.

2. The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to claim 1, characterized in that, The statistical channel state information includes: the vertical wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The horizontal wave arrival angle of the line-of-sight path between the j-th smart metasurface and user k relative to the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is separated by the wave departure angle in the vertical direction of the smart metasurface. The line-of-sight path between the j-th smart metasurface and the base station is relative to the horizontal wave departure angle of the smart metasurface. j = 1, ..., R, where the line-of-sight path between the j-th smart metasurface and the base station is represented by the angle of arrival relative to the base station. j = 1, ..., R, the Rice factor β of the link from the j-th smart metasurface to the base station. j j = 1, ..., R; The equivalent instantaneous channel state information includes: the equivalent instantaneous channel information h from user k to the base station. k .

3. The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to claim 1 or 2, characterized in that, Users are grouped based on the distance between each smart metasurface and each user, including: a1) For each intelligent metasurface j, put all users into the allocatable user set Λ j ; a2) Initialize the service user candidate set for each smart metasurface Initialize the number of alternating assignment rounds t = 1; a3) In the t-th round of allocation, initialize the smart metasurface index n = 1 for the current user to be allocated; a4) represents the nth intelligent metasurface from the allocatable user set Λ n Select the nearest user τ n Update the service user candidate set Π of the intelligent metasurface n n =Π n ∪{τ n }, update the set of allocatable users for each smart metasurface to Λ j =Λ j \{τ n },j=1,…,R, update the smart metasurface index n=n+1 for the current user to be assigned; a5) Repeat step a4) until n = R + 1 or Stop when the time is right, update the alternation allocation round number t = t + 1, and jump to step a3) when t ≤ K / R, otherwise stop.

4. The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to claim 2, characterized in that, User scheduling is performed using statistical channel state information between each smart metasurface and each user. A greedy, minimum-maximum correlation user scheduling algorithm is employed, including: b1) Initialize the system's already scheduled user set Initialize the system to have 0 scheduled users (s = 0). b2) Randomly schedule a service user π1 for intelligent metasurface 1 from the candidate user set Π1, update the system's scheduled user set Ξ=Ξ∪{π1}, and update the system's scheduled user count s=1; b3) Let j = s + 1, initialize the candidate set of service users for the j-th intelligent metasurface Π j Users k = 1, ..., K j The maximum correlation is ρ k,j =0,K j Represents set Π j The number of users in the set Π j Each user k, k = 1, ..., K j Calculate its maximum correlation ρ k,j : Where l is the sequence number of the scheduled smart metasurface, π l This represents the service user scheduled by the l-th intelligent metasurface. This represents the line-of-sight component from the l-th smart metasurface to the j-th smart metasurface. This represents the line-of-sight component from the l-th intelligent metasurface to the service user scheduled by the l-th intelligent metasurface. This represents the view distance component from user k to the j-th smart metasurface. The vector represents the view distance component from user k to the l-th smart metasurface. h represents the number of rows of reflective cells in the vertical direction of the smart metasurface, and v represents the number of reflective cells per row in the horizontal direction of the smart metasurface. and Let η represent the large-scale fading coefficients from the service user scheduled to the l-th smart metasurface to the j-th and l-th smart metasurfaces, respectively. k,j and η k,l Let d represent the large-scale fading coefficients from user k to the j-th and l-th smart metasurfaces, respectively. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents the Kronecker product, superscript (·). H Represents conjugate transpose; b4) Schedule the service users of the j-th intelligent metasurface block to its candidate user set Π j The user with the lowest maximum relevance: b5) Update the system's scheduled user set to Ξ=Ξ∪{π} j The number of users already scheduled by the system is updated to s = s + 1. b6) Repeat steps b3) to b5) until s = R + 1.

5. The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to claim 4, characterized in that, The phase shift design of smart metasurfaces is carried out using statistical channel state information between the cell base station and each smart metasurface, as well as between each smart metasurface and each user. This includes: c1) Generate an N-dimensional discrete Fourier codebook C = {c 1,1 ,...,c 1,v ,...,c h,1 ,...,c h,v }, where code words c2) Select the optimal γ discrete Fourier transform candidate codewords for the j-th smart metasurface: in, Let the vector represent the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. η k,j d represents the large-scale fading coefficient of the link from the service user scheduled to the j-th smart metasurface. R The distance between adjacent reflective elements on the intelligent reflective surface is λ, where λ is the carrier wavelength, and the symbol is λ. Represents Kronecker; c3) Combine the discrete Fourier transform candidate codewords of the R-block intelligent metasurface to obtain the quantity set γ. R Discrete Fourier Transform Candidate Codeword Combinations k j =1,…,γ, with the goal of maximizing and approximately ergodic spectral efficiency, the optimal discrete Fourier transform codeword combination is selected: in, Describe the optimal discrete Fourier transform codeword of the intelligent metasurface j. To schedule user π i The approximate ergodic efficiency is expressed as: Where p is the transmission power of each user, ξ j β represents the fading coefficient of the link from the smart metasurface j to the base station. j Represents the Rice factor of the smart metasurface j-to-base station link. This represents the line-of-sight component from the smart metasurface j to the base station. This represents the line-of-sight component from the j-th intelligent metasurface to the service user scheduled on the j-th intelligent metasurface. Let represent the large-scale fading coefficient of the link from the service user scheduled to the j-th intelligent metasurface, [·]. k This indicates the deletion of the k-th column of the matrix, and ψ(·) represents the digamma function operation; c4) Set the reflection coefficient matrix of the j-th smart metasurface to...

6. The user scheduling and transmission method of the intelligent metasurface-assisted uplink communication system according to claim 1 or 5, characterized in that, The design of a base station linear receiver utilizes the equivalent instantaneous channel state information between scheduled users and the base station, including: The base station linear receiver is designed as a zero-forcing receiver, wherein the zero-forcing receiver is: W ZF =(H H H) -1 H H Where H = [h1, h2, ..., h R ] represents the joint channel matrix of R scheduled users, h R Let represent the equivalent instantaneous channel vector between the R-th scheduling user and the base station.

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