An active intelligent reflecting surface assisted communication system mode selection method

Abstract

The application discloses an active intelligent reflecting surface (ARIS) assisted communication system mode selection method, which comprises the following steps: 1) at the end of the last communication time slot, the system acquires the path loss of a current transmitting end-ARIS- receiving end, the transmitting power of the transmitting end, the thermal noise power introduced by the ARIS and the noise power at the receiving end; 2) according to the acquired system parameters, the threshold is calculated by considering the power constraints of the transmitting end and the ARIS; 3) the ARIS surface reflecting unit area and the threshold are compared, and the mode that enables the receiving end to have the maximum signal-to-noise ratio is selected for the system to perform assisted transmission; 4) at the beginning of the current communication time slot, the ARIS mode is set, and the ARIS mode selected by the system is adopted to perform assisted communication; 5) at the end of the current communication time slot, the above steps are repeated until the communication is completed. The application takes the maximization of the signal-to-noise ratio of the system receiving end as the target, and provides a selection method for whether the ARIS adopts an amplification mode to assist the communication system, so that the performance of the ARIS assisted communication system can be effectively improved.

Description

Technical Field

[0001] This invention relates to a mode selection method for an active intelligent reflective surface-assisted communication system, belonging to the field of wireless communication technology. Background Technology

[0002] Intelligent Reflectors (RIS) are a key wireless channel control technology in 6G systems. RIS are two-dimensional arrays of passive or active reflective elements. To control the direction and intensity of signal propagation, RIS can adjust the phase and amplitude of the reflected signal. By intelligently reflecting the incident signal, RIS can improve signal quality, expand coverage, and enhance the spectral efficiency of wireless communication systems. Currently, research on RIS-assisted communication systems mainly focuses on active and passive beamforming. These studies treat all reflective elements of the RIS as a collective, without considering the specific location and size of each element. The spatial correlation of reflective elements is similar to that of an antenna, affected by the propagation environment and the distance between reflective elements. Therefore, improper design of the distance or area of ​​reflective elements can lead to phase shifts and interference between reflected signals. Unlike traditional passive intelligent reflectors (PRIS), active intelligent reflectors (ARIS) can overcome the "multiplicative fading" effect, but also generate additional thermal noise. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art by providing a mode selection method for an active intelligent reflective surface-assisted communication system, which configures each reflective unit, maximizes the signal-to-noise ratio at the system receiver, and selects an appropriate transmission mode to effectively improve system performance.

[0004] To achieve the above objectives, the present invention employs the following method:

[0005] A mode selection method for an active intelligent reflective surface (ARIS) assisted communication system, wherein the ARIS assisted communication system includes a transmitter, an ARIS capable of selectively enabling or disabling amplification modes, and a receiver; the mode selection includes an auxiliary communication mode with the ARIS amplification mode enabled and an auxiliary communication mode with the ARIS amplification mode disabled, and the specific method steps include:

[0006] Step 1: At the end of the previous communication time slot, obtain the path loss from the transmitter to the ARIS and from the ARIS to the receiver, the transmit power of the transmitter, the thermal noise power introduced by the ARIS, and the noise power at the receiver.

[0007] Step 2: Obtain the ARIS reflection unit threshold Δ;

[0008] Step 3: At the beginning of the current communication time slot, based on the comparison result of the ARIS reflection unit area and Δ, the ARIS mode is set: when the ARIS reflection unit area is less than the threshold Δ, the ARIS amplification mode is turned on; otherwise, the ARIS amplification mode is turned off.

[0009] Step 4: At the end of the current communication time slot, repeat the above steps until the communication ends.

[0010] Furthermore, in step 1, the channel coefficients between the transmitter-ARIS and the receiver both conform to the Rayleigh fading model.

[0011] Furthermore, in step 2, the calculation formula for the ARIS reflection unit threshold Δ is as follows:

[0012]

[0013] Among them, P max This indicates the maximum transmit power of the transmitter when ARIS is in amplification mode. This indicates the maximum reflection power of ARIS. This represents the maximum transmit power of the transmitter when the ARIS amplification mode is off; N represents the number of ARIS reflector units, μ h μ g These represent the path losses between the transmitter and the ARIS, and between the ARIS and the receiver, respectively. σ 2 These represent the thermal noise power introduced by ARIS and the noise power at the receiver, respectively.

[0014] Furthermore, the ARIS reflection unit threshold Δ is the area of ​​the reflection unit that makes the maximum signal-to-noise ratio of the receiver equal when the ARIS amplification mode is on and off.

[0015] Furthermore, the steps for obtaining the maximum signal-to-noise ratio at the receiver when ARIS is in amplification mode are as follows:

[0016] Step 201: When ARIS is in amplification mode, the ARIS reflection coefficient matrix... ARIS introduces thermal noise Φz, and the received signal at the receiver is represented as:

[0017]

[0018] Where β and θ n These represent the amplification factor and phase shift of the reflecting unit, respectively. It follows a complex Gaussian distribution, I N Describes an N×N identity matrix, 0 NLet P represent the transmit power of the transmitter, x represent the transmit signal of the transmitter, and g and h represent the channels between the transmitter and the ARIS, and between the ARIS and the receiver, respectively. This indicates the noise at the receiving end;

[0019] Step 202: Constrained by the power of the transmitter and ARIS, the following optimization problem is established to maximize the signal-to-noise ratio (SNR) at the receiver. ARIS :

[0020]

[0021] Step 203: Solve the optimization problem using the Lagrange multiplier method, P, θ n The optimal solutions are as follows:

[0022]

[0023] Among them, h n g n Let h and g represent the nth sub-channels respectively, and ∠ represent the phase shift of the sub-channel;

[0024] Substitution ||Φh|| 2 =β 2 Nμ h S n The optimal solution for β is obtained:

[0025]

[0026] Among them, S n Let n be the area of ​​the nth reflective unit in ARIS;

[0027] Step 204: According to the law of large numbers, as N→∞, ||gΦ|| 2 =β 2 Nμ g S n Substituting into the optimization problem, the maximum signal-to-noise ratio at the receiver is:

[0028]

[0029] Furthermore, the steps for obtaining the maximum signal-to-noise ratio at the receiver when ARIS's amplification mode is off are as follows:

[0030] Step 205: When ARIS amplification mode is off, the ARIS reflection coefficient matrix... Due to power constraints at the transmitter, the following optimization problem is established to maximize the signal-to-noise ratio (SNR) at the receiver. PRIS :

[0031]

[0032]

[0033] Among them, P B Indicates the transmission power of the transmitting end;

[0034] Step 206: Utilizing optimal phase shift design

[0035] Substituting into the optimization problem, the maximum signal-to-noise ratio at the receiver is obtained as follows:

[0036]

[0037] Furthermore, this makes SNR' ARIS =SNR' PRIS The area of ​​the established ARIS reflective cell is the reflective cell threshold Δ.

[0038] The present invention also provides a system for pattern selection based on the method described above, comprising:

[0039] The parameter acquisition module is used to acquire, at the end of the previous communication time slot, the path loss between the transmitter and ARIS, the path loss between ARIS and the receiver, the transmit power of the transmitter, the thermal noise power introduced by ARIS, and the noise power at the receiver.

[0040] The threshold calculation module is used to obtain the ARIS reflection unit threshold Δ.

[0041] The ARIS mode selection module is used to set the ARIS mode at the beginning of the current communication time slot based on the comparison results of the ARIS reflection unit area and Δ.

[0042] The present invention also provides a computer-readable storage medium for storing one or more programs, said one or more programs including instructions that, when executed by a computing device, cause the computing device to perform the method described above.

[0043] The present invention also provides an active intelligent reflective surface-assisted communication system mode selection device, comprising one or more processors, one or more memories, and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing the methods described above.

[0044] Compared with existing methods, the present invention has the following technical effects: The mode selection method of the active intelligent reflective surface assisted communication system of the present invention, on the one hand, considers the impact of the configuration of the ARIS reflective unit and whether the amplification mode is enabled on the system performance, and establishes an ARIS assisted communication system model; on the other hand, with the goal of maximizing the signal-to-noise ratio at the system receiver, it provides a method for mode selection of the ARIS assisted communication system, which can effectively improve the performance of the ARIS assisted communication system. Attached Figure Description

[0045] Figure 1 A diagram of the ARIS-assisted communication system model for this method;

[0046] Figure 2 Experimental simulation of a mode selection method for an active intelligent reflective surface-assisted communication system. Detailed Implementation

[0047] To make the objectives, technical methods, and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] According to an embodiment of the present invention, an active intelligent reflective surface-assisted communication system mode selection method is provided. The system model in this example is as follows: Figure 1 As shown, this system is an ARIS-assisted communication system. Considering the blockage of the direct link between the transmitter (base station BS) and receiver (user UE) with a single antenna, an ARIS with N reflector units is used to assist communication. Each reflector unit is configured with a horizontal width of l. H Vertical width is l V The rectangle has a reflective element area of ​​S. n =l H l V , n = 1, 2, ..., N. The channel coefficients between BS-ARIS and ARIS-UE both follow the Rayleigh fading model, and the path loss is μ. h μ g .

[0049] The specific steps of the method of the present invention are as follows:

[0050] Step 201: When ARIS is in amplification mode, the ARIS reflection coefficient matrix... in, θ n ∈[0,2π] represent the amplification factor and phase shift of the active unit, respectively. The noise introduced by the ARIS unit is Φz. It follows a complex Gaussian distribution. The received signal of the UE is represented as:

[0051]

[0052] Where P represents the transmit power of the BS in the ARIS-assisted communication system, and x represents the transmit signal of the BS. These are the channels for BS-ARIS and ARIS-UE, respectively. It is noise at the UE.

[0053] Step 202: Constrained by the power of BS and ARIS, the following model is established to maximize the signal-to-noise ratio (SNR) at the UE. ARIS :

[0054]

[0055] stC1:P≤P max

[0056] C2: Among them, P max This indicates the maximum transmit power at BS when ARIS is in amplification mode. This indicates the maximum reflection power of ARIS.

[0057] Step 203: Solve the optimization problem using the Lagrange multiplier method.

[0058] P opt =P max

[0059]

[0060] Substitution ||Φh|| 2 =β 2 Nμ h S n get

[0061]

[0062] Step 204: According to the law of large numbers, as N→∞,

[0063] ||gΦ|| 2 =β 2 Nμ g S n .

[0064] Substituting into the optimization problem, the maximum signal-to-noise ratio at the UE of the ARIS-assisted SISO system is:

[0065]

[0066] Step 205: When ARIS turns off amplification mode, the reflection coefficient matrix becomes BS transmit power is P BConstrained by the power of the BS, the following model is established to maximize the signal-to-noise ratio (SNR) at the UE. PRIS :

[0067]

[0068] stC1:

[0069] Step 206: Utilizing optimal phase shift design

[0070]

[0071] Substituting into the optimization problem, the maximum signal-to-noise ratio at the UE of the ARIS assisted communication system is:

[0072]

[0073] In the formula, This indicates the maximum transmit power at BS when ARIS's amplification mode is off.

[0074] Step 207: Based on the maximum signal-to-noise ratio obtained by the system when ARIS amplification mode is enabled and disabled, when SNR' ARIS =SNR' PRIS The required area of ​​the reflective element is the reflective element threshold, expressed as:

[0075]

[0076] Step 208: Compare the ARIS surface reflective cell area with the threshold Δ, and select a mode that results in a higher signal-to-noise ratio for auxiliary transmission;

[0077]

[0078] Specifically, when the area of ​​the reflective unit is less than the threshold Δ, ARIS activates the amplification mode auxiliary communication system; otherwise, ARIS deactivates the amplification mode auxiliary communication system.

[0079] Step 209: At the beginning of this communication time slot, ARIS mode is set according to the transmission mode selected at the end of the previous time slot.

[0080] Step 210: At the end of this communication time slot, repeat the above steps until the communication ends.

[0081] Figure 2This paper demonstrates the impact of reflective element area on communication system performance and the proposed active intelligent reflective surface-assisted communication system mode selection method. Assuming a limited power budget for the communication system and a reflective element number N of 512, it is evident that the ARIS amplification mode performs better when N is fixed and the reflective element area is small. This is because ARIS can overcome the "multiplicative fading" effect in the PRIS-assisted cascaded channel. However, as the area of ​​each reflective element increases, PRIS outperforms ARIS. This is because the excessive thermal noise of ARIS affects the signal-to-noise ratio. Furthermore, the curves confirm that the proposed active intelligent reflective surface-assisted communication system mode selection method ensures maximum system signal-to-noise ratio.

[0082] Based on the same technical solution, the present invention also provides a system for pattern selection based on the method described above, comprising:

[0083] The parameter acquisition module is used to acquire, at the end of the previous communication time slot, the path loss between the transmitter and ARIS, the path loss between ARIS and the receiver, the transmit power of the transmitter, the thermal noise power introduced by ARIS, and the noise power at the receiver.

[0084] The threshold calculation module is used to obtain the ARIS reflection unit threshold Δ.

[0085] The ARIS mode selection module is used to set the ARIS mode at the beginning of the current communication time slot based on the comparison results of the ARIS reflection unit area and Δ.

[0086] Based on the same technical solution, the present invention also discloses a computer-readable storage medium storing one or more programs, wherein the one or more programs include instructions that, when executed by a computing device, cause the computing device to perform the above-described active intelligent reflective surface-assisted communication system mode selection method.

[0087] Based on the same technical solution, the present invention also discloses an active intelligent reflective surface assisted communication system mode selection device, including one or more processors, one or more memories and one or more programs, wherein the one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, and the one or more programs include instructions for performing the above-described active intelligent reflective surface assisted communication system mode selection method.

[0088] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0089] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0091] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An active intelligent reflecting surface (ARIS)-assisted communication system mode selection method, comprising: The ARIS auxiliary communication system comprises a transmitting end, an ARIS capable of selecting an open or closed amplification mode, and a receiving end; the mode selection comprises an auxiliary communication mode in which the ARIS is in the open amplification mode and an auxiliary communication mode in which the ARIS is in the closed amplification mode, and the specific method steps comprise: Step 1: at the end of a previous communication time slot, the path loss between the transmitting end-ARIS, the ARIS-receiving end, the transmitting power of the transmitting end, the thermal noise power introduced by the ARIS, and the noise power at the receiving end are obtained; Step 2: the ARIS reflecting unit threshold Δ is obtained, the ARIS reflecting unit threshold Δ being the area of the reflecting unit that makes the maximum signal-to-noise ratio of the receiving end when the ARIS is in the open amplification mode equal to the maximum signal-to-noise ratio of the receiving end when the ARIS is in the closed amplification mode; Step 3: at the beginning of a current communication time slot, the ARIS mode is set according to the comparison result of the ARIS reflecting unit area and Δ: when the ARIS reflecting unit area is less than the threshold Δ, the ARIS is in the open amplification mode, otherwise the ARIS is in the closed amplification mode; Step 4: at the end of the current communication time slot, the above steps are repeated until the communication ends.

2. The active intelligent reflecting surface aided communication system mode selection method of claim 1, wherein, In step 1, the channel coefficients between the transmitting end-ARIS and the ARIS-receiving end both obey the Rayleigh fading model.

3. The method of claim 1, wherein, In step 2, the calculation formula of the ARIS reflecting unit threshold Δ is as follows: where Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode, max Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode, Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode, Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode; N denotes the number of ARIS reflecting units, and h Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode; N denotes the number of ARIS reflecting units, and g Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode; N denotes the number of ARIS reflecting units, and Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode; N denotes the number of ARIS reflecting units, and 2 Pmax,ARIS denotes the maximum transmit power of the transmitter when the ARIS is turned on the amplify-and-forward mode; N denotes the number of ARIS reflecting units, 4. The method of claim 3, wherein, The steps for obtaining the maximum signal-to-noise ratio of the receiving end when the ARIS is in the open amplification mode are as follows: Step 201: When ARIS opens the amplification mode, the ARIS reflection coefficient matrix ARIS introduces thermal noise Φz, and the received signal at the receiving end is represented as: where β and θ n denote the amplification factor and phase shift of the reflecting unit, respectively, subject to complex Gaussian distribution, I N denotes the N × N identity matrix, 0 N denotes the N × 1 zero vector, P denotes the transmit power of the transmitting end, x denotes the transmit signal of the transmitting end, g, h denote the channel between the transmitting end-ARIS and the ARIS-receiving end, respectively, l ~ CN(0, σ 2 ) denotes the noise at the receiving end; Step 202: Subject to the power constraints of the transmitting end and the ARIS, the following optimization problem is established to maximize the signal-to-noise ratio (SNR) of the receiving end ARIS : Step 203: solve the optimization problem using the Lagrange multiplier method, P, θ n The optimal solutions of P, θ and P are respectively: wherein h n , g n denote the nth subchannel of h, g, respectively, and ∠ denotes the phase shift of the subchannel. Substitute ||Φh|| 2 = β 2 Nμ h S n Get the optimal solution of β: where S n is the area of the nth ARIS. Step 204: According to the law of large numbers, when N→∞, ||gΦ|| 2 = β 2 Nμ g S n ; the signal-to-noise ratio of the receiving end is obtained by substituting the optimization problem:

5. The active intelligent reflecting surface aided communication system mode selection method of claim 4, wherein, The steps for obtaining the maximum signal-to-noise ratio of the receiving end when the ARIS is in the closed amplification mode are as follows: Step 205: When the ARIS turns off the amplification mode, the ARIS reflection coefficient matrix Subject to the power constraint at the transmitting end, the following optimization problem is established to maximize the signal-to-noise ratio (SNR) at the receiving end PRIS : where P B represents the transmit power of the transmitting end; Step 206: Utilizing optimal phase shift design Substitute the optimization problem to get the maximum signal-to-noise ratio of the receiving end:

6. The active intelligent reflecting surface aided communication system mode selection method of claim 5, wherein, such that SNR' = SNR ARIS = SNR' PRIS The area of the ARIS reflecting unit for which this is true is the reflecting unit threshold Δ.

7. A system for mode selection based on the method of any one of claims 1 to 6, characterized by Comprise: A parameter acquisition module for obtaining, at the end of a previous communication time slot, the path loss between the transmitting end-ARIS, the ARIS-receiving end, the transmitting power of the transmitting end, the thermal noise power introduced by the ARIS, and the noise power at the receiving end; A threshold calculation module for obtaining the ARIS reflecting unit threshold Δ; An ARIS mode selection module for setting the ARIS mode at the beginning of a current communication time slot according to the comparison result of the ARIS reflecting unit area and Δ.

8. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions that are executable to: The instructions, when executed by a computing device, cause the computing device to perform the method of any one of claims 1 to 6.

9. An active intelligent reflecting surface assisted communication system mode selection device, characterized in that, Comprise one or more processors, one or more memories, and one or more programs, wherein one or more programs are stored in the one or more memories and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing the method of any one of claims 1 to 6.

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