IRS (Inter-Reference Signal) transmission method under non-ideal CSI (Channel State Information) condition

Abstract

The invention discloses an IRS (Independent Reference Signal) transmission method under a non-ideal CSI (Channel State Information) condition. The method mainly comprises the following steps: S1, determining an optimal incoherent detection algorithm of an SIMO + IRS system; s2, determining a unique decomposable condition of the incoherent received signal; reliable communication of an incoherent system depends on construction of a unique decomposable constellation, an IRS system is considered and combined, and a unique decomposition theory is planned to be used as a design criterion of an incoherent space-time coding scheme in consideration of abnormal complexity of a decoding error probability expression in IRS incoherent transmission analysis; s3, carrying out IRS system parameterization unique decomposable constellation design; s4, designing a constellation optimization method based on a least square method criterion; and S5, carrying out incoherent optimal transmission strategy design on the IRS, and constructing an optimization equation of space-time coding and IRS phase shift under incoherent transmission. According to the method, the reliable and safe transmission of a communication system can be remarkably improved, and a relatively high transmission rate is obtained through algorithm optimization.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to an IRS transmission method under non-ideal CSI conditions. Background Art

[0002] Most of the current research based on IRS assumes that its channel state information (CSI) is perfectly known. However, the IRS signal processing capability is limited and there is no RF device, so it is difficult to use the IRS end to perform channel estimation. Secondly, the large number of IRS units requires a large number of pilots for channel estimation, resulting in excessive system overhead and long information transmission delay, which is impractical in fast-changing channels or low-latency transmission scenarios.

[0003] Compared with traditional coherent transmission, the incoherent communication system does not require the real-time CSI of the system when detecting and demodulating at the receiving end, so it can deal with the channel estimation error problem when the channel changes rapidly. In addition, since there is no need to send pilot information during the communication process, it can effectively reduce the communication delay. Based on these advantages, incoherent communication is particularly suitable for communication occasions with strict requirements on delay, and has begun to attract the attention of researchers.

[0004] First, the use of pilot-based data communication to achieve IRS transmission is bound to reduce transmission efficiency and generate certain transmission delays, which is not suitable for low-latency industrial control scenarios. This phenomenon is more obvious for IRS communication systems with multiple reflection units. Therefore, it is more practical to use pilot-free incoherent communication to achieve low-latency and reliable transmission of IRS systems. Secondly, the ultra-high mobility of the user end often means a drastic change in the user channel fading coefficient, which also greatly reduces the accuracy of channel estimation. There are no reports on the use of multiple base station antennas or even large-scale antennas and combined space-time coding strategies to improve the reliability of the IRS transmission system. Therefore, it is of great research significance to study how to use incoherent communication to achieve the transmission of the IRS system in communication scenarios with strict requirements on delay and transmission efficiency. Summary of the invention

[0005] The purpose of the present invention is to address the defects and shortcomings of the above-mentioned prior art and propose an IRS transmission method under non-ideal CSI conditions. The present invention first studies the design of space-time coding of the IRS system based on the unique decomposition theory under no CSI conditions, and combines the optimal phase shift to realize the system's incoherent communication to meet the low-latency reliable transmission scenario. Then, on the basis of the non-ideal IRS, the low-latency communication scenario based on the IRS fast-changing channel is further considered, the application of incoherent transmission based on the IRS system in fast-changing channels and low-latency transmission scenarios is studied, and the corresponding space-time coding and optimal phase shift are designed.

[0006] The technical solution adopted by the present invention to solve the technical problem is: an IRS transmission method under non-ideal CSI conditions. The method first considers the design of a transmission strategy in an IRS communication scenario where no CSI is available, and specifically includes the following steps:

[0007] Step S1: Determination of the optimal non-coherent detection algorithm of the SIMO+IRS system, considering that the transmitter is a single-antenna user and the receiver is an M-antenna base station, given the IRS phase shift parameter, assuming that there is no channel estimation and the specific probability distribution of the channel is unknown, and the receiver only has the second-order information of the channel, a two-symbol period transmission strategy is designed, and s1 and s2 are sent in the first and second symbol periods respectively;

[0008] Step S2: Determine the unique decomposable condition of the incoherent received signal. The reliable communication of the incoherent SIMO system depends on the construction of a unique decomposable constellation. Here, the IRS system is considered. Considering that the expression of the decoding error probability in the IRS incoherent transmission analysis is extremely complex, the unique decomposition theory is used as the design criterion of the incoherent space-time coding scheme to provide an effective solution for realizing the reliable transmission of IRS in specific scenarios.

[0009] Step S3: Design a unique decomposable constellation for parameterization of the IRS system. In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s is normalized to obtain the necessary conditions that the unique decomposable constellation s satisfies;

[0010] Step S4: Based on the constellation optimization method design under the least squares criterion, according to the IRS incoherent transmission characteristics, the objective function of signal detection is established based on the least squares criterion, and the first kind of Riemann distance (D R1 ) as the constellation measurement criterion, and establish the optimization equation of the unitary space-time constellation suitable for SIMO+IRS transmission;

[0011] Step S5: Design an optimal incoherent transmission strategy for IRS, and construct the optimization equations for space-time coding and IRS phase shift under incoherent transmission. Since the constructed optimization equation is a non-convex optimization equation, the block descent method is used to group the variables first in combination with the characteristics of the equation, and then the variables are iteratively optimized by group until convergence.

[0012] Furthermore, step S1 of the present invention includes the following contents:

[0013] The transmitter is a single-antenna user, the receiver is an M-antenna base station, and M>>1; f and G represent the transmission channels from the user to the IRS and from the IRS to the base station, respectively. The total equivalent channel h is:

[0014] h=[fΘg1,...,fΘg M ] T ∈CM×1

[0015]

[0016] Considering the communication without channel estimation, the specific probability distribution of the channel is unknown, and the receiving end only has the second-order information of the channel. A two-symbol period transmission strategy is designed. The first and second periods send s1 and s2 respectively. The received signal is:

[0017] Y=hs T +n0. (1)

[0018] Y=(y1,y2)∈C M×2 ,y1=hs1+n1, y2=hs2+n2, s=(s1,s2) T ,n0=(n1,n2)∈C M×2 ;

[0019] Where g1 represents the channel vector between IRS and the first base station antenna, g M represents the channel vector between IRS and the mth base station antenna, Represents the diagonal phase shift matrix of IRS. There are N reflection units on IRS, where θ1 represents the phase shift on the lth reflection unit, θ n represents the phase shift on the nth reflection unit, and n0 represents additive white Gaussian noise.

[0020] Furthermore, step S2 of the present invention includes the following contents:

[0021] Reliable communication of the incoherent SIMO system depends on the construction of a uniquely decomposable constellation. Combined with the IRS system, the condition for the unique decomposability of the received signal can be expressed as follows: From formula (1), we can get Therefore, Y H The necessary and sufficient conditions for Y / M to have a unique solution with respect to s (i.e., s is the only decomposable constellation) are: ( S is a set of 2-dimensional column vectors), then there must be in, Represents the noise power.

[0022] Furthermore, step S3 of the present invention includes the following contents:

[0023] Normalize s: ||s||=α, and In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s can be redefined:

[0024]

[0025] (2) where s is the constellation point of S (α, θ and e jφ Constellation Q α ,Q θ and Q φ The necessary conditions for the unique decomposable constellation S to be satisfied are: Based on (2) parameterized coding scheme: If α>0, 0≤φ≤2π, Constellation It is the only decomposable constellation.

[0026] Furthermore, step S4 of the present invention includes the following contents:

[0027] Since the accurate probability density function f(h) of channel h in the IRS system is complex and it is difficult to obtain an accurate closed-form expression, it is difficult to obtain the probability function of the system receiving signal in the presence of noise; based on this, the objective function of signal detection based on the least squares criterion is established as follows:

[0028]

[0029] s incoherent detector is essentially equivalent to finding With the minimum Riemann distance of the first kind The matrix Therefore, this sub-topic adopts the first kind of Riemann distance (D R1 ) as a criterion for measuring constellations:

[0030]

[0031] It can be further expressed as containing The expression The optimization equation based on the optimal constellation is as follows:

[0032]

[0033] n α +n α +n α =K.(5c)

[0034]

[0035] Where K in (5c) is the number of bits carried by constellation point S, and |S| = 2 K (K≥1); (5d) is the energy limit of the sending end.

[0036] Furthermore, step S5 of the present invention includes the following contents:

[0037] The optimization equations of space-time coding and IRS phase shift under incoherent transmission conditions are constructed, and the following optimization equations are constructed;

[0038]

[0039] stθ n ∈F,(6b)

[0040] s∈S..(6c)

[0041] Since the optimization equation (6) is a non-convex optimization equation, the block descent method is used in this project in combination with the characteristics of the optimization equation. That is, according to the structure of the optimization problem, the variables are grouped, and the optimization variables in the optimization equation are divided into the optimal phase shift variable group based on the IRS reflection surface and the space-time coding related variable group based on the unique decomposition theory. The grouped variables are iterated one by one until convergence.

[0042] Beneficial effects:

[0043] 1. The present invention provides a SIMO non-coherent communication system model based on IRS to solve the communication problem of how to perform reliable transmission under the condition of no CSI.

[0044] 2. The present invention provides a secure transmission scheme for a SIMO incoherent communication system based on IRS. The incoherent transmission based on the unique decomposition theory reduces the symbol error rate of the system.

[0045] 3. The present invention provides an optimization method for secure transmission of a SIMO incoherent communication system based on IRS. A higher transmission rate is obtained through algorithm optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a system model diagram of the present invention.

[0047] Figure 2 The present invention is a flow chart of the method.

[0048] Figure 3 FIG. 4 is a comparison diagram of the effects of the phase shift level of the IRS system of the present invention and the number of IRS reflection units on the system performance.

[0049] Figure 4 This is a comparison diagram of the impact of the number of transmission bits and the number of smart reflective surface units on system performance of the present invention. DETAILED DESCRIPTION

[0050] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0051] like Figure 1As shown, the distributed IRS-assisted communication system of the present invention includes: a single-antenna user, M-antenna base stations, and M>>1. Uplink transmission is adopted. Assume that the channel coefficients from the user to the IRS and from the IRS to the base station are f and G respectively, and all channels obey the small-scale Rice fading model.

[0052] Consider the communication without channel estimation, and assume that the specific probability distribution of the channel is unknown, and the receiver only has the second-order information of the channel. Here we intend to design a two-symbol period transmission strategy, sending s1 and s2 in the first and second symbol periods respectively. Received signal:

[0053] Y=hs T +n0.

[0054] where Y=(y1,y2)∈C M×2 ,y1=hs1+n1, y2=hs2+n2, s=(s1,s2) T ,n0=(n1,n2)∈C M×2 g1 represents the channel vector between IRS and the first base station antenna, g M represents the channel vector between IRS and the mth base station antenna, Represents the diagonal phase shift matrix of IRS. There are N reflection units on IRS, where θ1 represents the phase shift on the lth reflection unit, θ n represents the phase shift on the nth reflection unit. n0 represents additive Gaussian white noise.

[0055] Next, the unique decomposable condition of the incoherent received signal is determined. The reliable communication of the incoherent SIMO system depends on the construction of a uniquely decomposable constellation. Here, considering the IRS system, the unique decomposable condition of the received signal can be expressed as: Set From formula (1), we can get Therefore, Y H The necessary and sufficient conditions for Y / M to have a unique solution with respect to s (i.e., s is the only decomposable constellation) are: ( S is a set of 2-dimensional column vectors), then there must be

[0056] in, Represents the noise power. Normalize s: and In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s can be redefined:

[0057]

[0058] Where s is the constellation point of S (α, θ and e jφConstellation Q α ,Q θ and Q φ The necessary conditions for the unique decomposable constellation S to be satisfied are: Based on (2) parameterized coding scheme: If Constellation It is the only decomposable constellation.

[0059] Since the accurate probability density function f(h) of channel h in the IRS system is complex and difficult to obtain an accurate closed-form expression, it is difficult to obtain the probability function of the system receiving the signal in the presence of noise. Based on this, it is proposed to establish the following signal detection objective function based on the least squares criterion:

[0060]

[0061] s incoherent detector is essentially equivalent to finding With the minimum Riemann distance of the first kind The matrix Therefore, the first kind of Riemann distance is used As a criterion for measuring constellations:

[0062]

[0063] It can be further expressed as containing The expression The optimization equation based on the optimal constellation is as follows:

[0064]

[0065] n α +n α +n α =K.(5c)

[0066]

[0067] Where K in (5c) is the number of bits carried by constellation point S, and |S| = 2 K (K≥1). (5d) is the energy limit of the transmitter.

[0068] Then, the optimization equations for space-time coding and IRS phase shift under incoherent transmission conditions are constructed. The following optimization equations are constructed.

[0069]

[0070] stθ n ∈F,

[0071] s∈S..

[0072] Since the optimization equation is a non-convex optimization equation, it is difficult to solve it directly using optimization tools. Therefore, we combine the characteristics of the optimization equation in the project and use the block descent method to "divide and conquer" the optimization problem. That is, according to the structure of the optimization problem, the variables are grouped (in this project, the optimization variables in the optimization equation are mainly divided into the optimal phase shift variable group based on the IRS reflection surface and the space-time coding related variable group based on the unique decomposition theory), and the grouped variables are iterated one by one until convergence. The algorithm flow of the present invention is as follows: Figure 2 As shown, the specific steps include:

[0073] a). Study the unknown CSI and probability distribution in the IRS system, determine and design the parameterized unique decomposable constellation of the IRS system, and use the Riemann distance as the measurement criterion to optimize the space-time coding, and further jointly design the optimal space-time coding and the optimal phase shift according to the optimization goal;

[0074] b). Analyze the channel transmission characteristics of the IRS system, and use approximate analysis to obtain a closed expression for the channel probability distribution in relevant communication scenarios. Based on the unique decomposition theory, determine and design the parameterized decomposable constellation of the IRS system. On this basis, construct the optimization equation for maximizing system users and rates, and use block optimization and other principles to design the optimal space-time coding and optimal phase shift of the IRS system. Further explore accelerated block optimization methods;

[0075] c). Study the incoherent transmission based on NOMA+IRS, explore the space-time block coding structure and design criteria for different users, analyze the complexity of the designed coding strategy and evaluate its applicability.

[0076] Secondly, we consider the research on incoherent space-time coding and optimal phase shift design based on IRS system. Starting from the unique decomposition theory, we design space-time coding with low complexity and high coding gain under the premise of relying only on limited channel information (only the probability distribution of IRS channel or the second-order statistical information of IRS channel). Following the principle of starting from the simple to the complex, we first focus on the optimal space-time coding and phase shift design of IRS under single antenna transmission, which mainly includes the following steps:

[0077] S1: Determination of the optimal non-coherent detection algorithm for the SIMO+IRS system. Consider the transmitter as a single-antenna user and the receiver as an M-antenna base station. Given the IRS phase shift parameters, assume that there is no channel estimation and the specific probability distribution of the channel is unknown, and the receiver only has the second-order information of the channel. Design a two-symbol period transmission strategy, and send s1 and s2 in the first and second symbol periods respectively.

[0078] S2: Determine the unique decomposable condition of the incoherent received signal. The reliable communication of the incoherent SIMO system depends on the construction of a unique decomposable constellation. Here, the IRS system is considered. Considering the extremely complex expression of the decoding error probability in the IRS incoherent transmission analysis, the unique decomposition theory is used as the design criterion of the incoherent space-time coding scheme to provide an effective solution for achieving reliable transmission of IRS in specific scenarios.

[0079] S3: Design a unique decomposable constellation for the IRS system parameters. In order to allow the receiving end to more accurately identify the received signal and achieve effective signal transmission, s is normalized to obtain the necessary conditions that the unique decomposable constellation s satisfies.

[0080] S4: Design of constellation optimization method based on the least squares criterion. According to the incoherent transmission characteristics of IRS, the objective function of signal detection is established based on the least squares criterion, and the first kind of Riemann distance (D R1 ) is used as the constellation measurement criterion, and the optimization equation of the unitary space-time constellation suitable for SIMO+IRS transmission is established.

[0081] S5: Design the incoherent optimal transmission strategy for IRS and construct the optimization equations for space-time coding and IRS phase shift under incoherent transmission. Since the constructed optimization equation is a non-convex optimization equation, the block descent method is used to group the variables first according to the characteristics of the equation, and then the variables are iteratively optimized by group until convergence.

[0082] Furthermore, in said S1, the following contents are included:

[0083] The transmitting end is a single-antenna user, the receiving end is an M-antenna base station, and M>>1. f and G represent the transmission channels from the user to the IRS and from the IRS to the base station, respectively. The total equivalent channel h is:

[0084] h=[fΘg1,...,fΘg M ] T ∈C M×1

[0085]

[0086] Consider the communication without channel estimation, and assume that the specific probability distribution of the channel is unknown, and the receiving end only has the second-order information of the channel. Here, a two-symbol period transmission strategy is designed, and s1 and s2 are sent in the first and second periods respectively. The received signal is:

[0087] Y=hs T +n0. (1)

[0088] Y=(y1,y2)∈C M×2,y1=hs1+n1, y2=hs2+n2, s=(s1,s2) T ,n0=(n1,n2)∈C M×2 .

[0089] Where g1 represents the channel vector between IRS and the first base station antenna, g M represents the channel vector between IRS and the mth base station antenna, Represents the diagonal phase shift matrix of IRS. There are N reflection units on IRS, where θ1 represents the phase shift on the lth reflection unit, θ n represents the phase shift on the nth reflection unit. n0 represents additive Gaussian white noise.

[0090] Further, in S2, the reliable communication of the incoherent SIMO system depends on the construction of a uniquely decomposable constellation. Here, considering the IRS system, the unique decomposable condition of the received signal can be expressed as: Set From formula (1), we can get Therefore, Y H The necessary and sufficient conditions for Y / M to have a unique solution with respect to s (i.e., s is the only decomposable constellation) are: ( S is a set of 2-dimensional column vectors), then there must be in, Represents the noise power.

[0091] Furthermore, in said S3, s is normalized: and In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s can be redefined:

[0092]

[0093] (2) where s is the constellation point of S (α, θ and e jφ Constellation Q α ,Q θ and Q φ The necessary conditions for the unique decomposable constellation S to be satisfied are: Based on (2) parameterized coding scheme: If α>0, 0≤φ≤2π, Constellation It is the only decomposable constellation.

[0094] Furthermore, in S4, since the accurate probability density function f(h) of the channel h in the IRS system is complex and it is difficult to obtain an accurate closed-form expression, it is difficult to obtain the probability function of the system receiving the signal in the presence of noise. Based on this, it is proposed to establish the following signal detection objective function based on the least squares criterion:

[0095]

[0096] s incoherent detector is essentially equivalent to finding With the minimum Riemann distance of the first kind The matrix Therefore, this sub-topic intends to use the first kind of Riemann distance As a criterion for measuring constellations:

[0097]

[0098] It can be further expressed as containing The expression The optimization equation based on the optimal constellation is as follows:

[0099]

[0100] n α +n α +n α =K.(5c)

[0101]

[0102] Where K in (5c) is the number of bits carried by constellation point S, and |S| = 2 K (K≥1). (5d) is the energy limit of the transmitter.

[0103] Furthermore, in S5, an optimization equation for space-time coding and IRS phase shift under non-coherent transmission conditions is constructed. The following optimization equation is constructed.

[0104]

[0105] stθ n ∈F,(6b)

[0106] s∈S..(6c)

[0107] Since the optimization equation (6) is a non-convex optimization equation, it is difficult to solve it directly using optimization tools. Therefore, in this project, we combine the characteristics of the optimization equation and intend to use the block descent method to "divide and conquer" the optimization problem. That is, according to the structure of the optimization problem, the variables are grouped (in this project, the optimization variables in the optimization equation are mainly divided into the optimal phase shift variable group based on the IRS reflection surface and the space-time coding related variable group based on the unique decomposition theory), and the grouped variables are iterated one by one until convergence.

[0108] The practical effects of the present invention are described in detail below in conjunction with simulation.

[0109] 1) Simulation conditions

[0110] The transmitting end is a single-antenna user with one IRS, and the receiving end is an M-antenna base station, where M>>1.

[0111] 2) Simulation results

[0112] In this embodiment, if Figure 3 , Figure 4 The figure shows the comparison of the effect of the IRS phase shift level and the number of IRS reflection units on the system symbol error rate in the present invention, and the comparison of the effect of the number of transmission bits and the number of intelligent reflection surface units on the system user transmission rate in the present invention. Figure 3 It can be observed that the symbol error rate of incoherent transmission based on the unique decomposition theory is significantly lower than the symbol error rate of QAM based on the training sequence, and the symbol error rate when the number of IRS reflection units N=30 is significantly lower than the symbol error rate when the number of reflection units N=20. Figure 4 It can be observed that: the higher the number of transmission bits, the higher the user transmission rate and the transmission rate based on continuous phase shift is basically the same as the transmission rate at 3 bits, and the user transmission rate increases with the increase in the number of smart reflective surface units.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An IRS transmission method under non-ideal CSI conditions, characterized in that: The method comprises the following steps: Step S1: Determination of the optimal non-coherent detection algorithm of the SIMO+IRS system, considering that the transmitter is a single-antenna user and the receiver is an M-antenna base station, given the IRS phase shift parameter, assuming that there is no channel estimation and the specific probability distribution of the channel is unknown, and the receiver only has the second-order information of the channel, a two-symbol period transmission strategy is designed, and s1 and s2 are sent in the first and second symbol periods respectively; Step S2: Determine the unique decomposable condition of the incoherent received signal. The reliable communication of the incoherent SIMO system depends on the construction of a unique decomposable constellation. Here, the IRS system is considered. Considering that the expression of the decoding error probability in the IRS incoherent transmission analysis is extremely complex, the unique decomposition theory is used as the design criterion of the incoherent space-time coding scheme to provide an effective solution for realizing the reliable transmission of IRS in specific scenarios. Step S3: Design a unique decomposable constellation for parameterization of the IRS system. In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s is normalized to obtain the necessary conditions that the unique decomposable constellation s satisfies; Step S4: Based on the constellation optimization method design under the least squares criterion, according to the IRS incoherent transmission characteristics, the objective function of signal detection is established based on the least squares criterion, and the first kind of Riemann distance is used As a constellation measurement criterion, an optimization equation for a unitary space-time constellation suitable for SIMO+IRS transmission is established; Step S5: Design an optimal incoherent transmission strategy for IRS, and construct the optimization equations for space-time coding and IRS phase shift under incoherent transmission. Since the constructed optimization equation is a non-convex optimization equation, the block descent method is used to group the variables first in combination with the characteristics of the equation, and then the variables are iteratively optimized by group until convergence.

2. The IRS transmission method under non-ideal CSI conditions according to claim 1, characterized in that: The step S1 includes the following contents: The transmitter is a single-antenna user, the receiver is an M-antenna base station, and M>>1; f and G represent the transmission channels from the user to the IRS and from the IRS to the base station, respectively. The total equivalent channel h is: h=[fΘg1,...,fΘg M ] T ∈C M×1 Considering the communication without channel estimation, the specific probability distribution of the channel is unknown, and the receiving end only has the second-order information of the channel. A two-symbol period transmission strategy is designed. The first and second periods send s1 and s2 respectively. The received signal is: Y=hs T +n0.(1) <h2 style=";text-align:left;direction:ltr">Y = (y1,y2)∈C<h2 style=";text-align:left;direction:ltr"> M×2 <h2 style=";text-align:left;direction:ltr"> y1 = hs1 + n1, y2 = hs2 + n2, s = (s1, s2)<h2 style=";text-align:left;direction:ltr"> T <h2 style=";text-align:left;direction:ltr"> ,n0=(n1,n2)∈C<h2 style=";text-align:left;direction:ltr"> M×2 <h2 style=";text-align:left;direction:ltr"> ; Where g1 represents the channel vector between IRS and the first base station antenna, g M represents the channel vector between IRS and the mth base station antenna, Represents the diagonal phase shift matrix of IRS. There are N reflection units on IRS, where θ1 represents the phase shift on the lth reflection unit, θ n represents the phase shift on the nth reflection unit, and n0 represents additive white Gaussian noise.

3. The IRS transmission method under non-ideal CSI conditions according to claim 1, characterized in that: The step S2 includes the following contents: Reliable communication of the incoherent SIMO system depends on the construction of a uniquely decomposable constellation. Combined with the IRS system, the condition for the unique decomposability of the received signal can be expressed as follows: From formula (1), we can get Therefore, Y H The necessary and sufficient conditions for Y / M to have a unique solution with respect to s (i.e., s is the only decomposable constellation) are: (s, S is a set of 2-dimensional column vectors), then there must be in, Represents the noise power.

4. The IRS transmission method under non-ideal CSI conditions according to claim 1, characterized in that: The step S3 includes the following contents: Normalize s: ||s||=α, and In order to allow the receiving end to more accurately identify the received signal and realize effective signal transmission, s can be redefined: (2) where s is the constellation point of S (α, θ and e jφ Constellation Q α ,Q θ and Q φ The necessary conditions for the unique decomposable constellation S to be satisfied are: Based on (2) parameterized coding scheme: If α>0, 0≤φ≤2π, Constellation It is the only decomposable constellation.

5. The IRS transmission method under non-ideal CSI conditions according to claim 1, characterized in that: The step S4 includes the following contents: Since the accurate probability density function f(h) of channel h in the IRS system is complex and it is difficult to obtain an accurate closed-form expression, it is difficult to obtain the probability function of the system receiving signal in the presence of noise; based on this, the objective function of signal detection based on the least squares criterion is established as follows: s incoherent detector is essentially equivalent to finding With the minimum Riemann distance of the first kind The matrix Therefore, this sub-topic adopts the first kind of Riemann distance As a criterion for measuring constellations: It can be further expressed as containing The expression The optimization equation based on the optimal constellation is as follows: n α +n α +n α =K.(5c) Where K in (5c) is the number of bits carried by constellation point S, and |S| = 2 K (K≥1); (5d) is the energy limit of the sending end.

6. The IRS transmission method under non-ideal CSI conditions according to claim 1, characterized in that: The step S5 includes the following contents: The optimization equations of space-time coding and IRS phase shift under incoherent transmission conditions are constructed, and the following optimization equations are constructed; s.t.θ n ∈F,(6b) s∈S..(6c) Since the optimization equation (6) is a non-convex optimization equation, the block descent method is used in this project in combination with the characteristics of the optimization equation. That is, according to the structure of the optimization problem, the variables are grouped, and the optimization variables in the optimization equation are divided into the optimal phase shift variable group based on the IRS reflection surface and the space-time coding related variable group based on the unique decomposition theory. The grouped variables are iterated one by one until convergence.

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