A novel low-power low-complexity active dual-functional reconfigurable intelligent surface unit and surface

Abstract

The application provides a novel low-power-consumption low-complexity active dual-function reconfigurable intelligent surface unit and surface, which comprises: an active load for amplifying an incident electromagnetic signal to obtain an amplified electromagnetic signal; a power distribution network for receiving the amplified electromagnetic signal transmitted by the active load and distributing the power of the amplified electromagnetic signal to obtain a power-distributed electromagnetic signal; a first phase shifter for receiving the power-distributed electromagnetic signal transmitted by the power distribution network, modulating the phase of the power-distributed electromagnetic signal, and outputting a modulated-phase electromagnetic signal; and a second phase shifter for receiving the power-distributed electromagnetic signal transmitted by the power distribution network and outputting the modulated-phase electromagnetic signal. Due to the low cost, low power consumption and easy installation of the active dual-function reconfigurable intelligent surface, the application can be widely promoted in the field of wireless communication.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a novel low-power, low-complexity active dual-function reconfigurable smart surface unit and surface. Background Technology

[0002] In recent years, 5G, the fifth-generation mobile communication system, has become a hot topic in the communications industry and academia. To achieve greater network capacity and more wireless device access, various wireless technologies, such as millimeter wave (mmWave), have been proposed and studied extensively over the past decade. However, in practical systems, achieving high-quality communication requires very expensive radio frequency chains and complex processing circuits. Furthermore, adding more active circuits to the wireless link can lead to more severe interference. Passive reconfigurable intelligent surfaces (RIS), which can reconfigure the wireless propagation environment through software-controlled reflection, are a promising solution for sustainable wireless network development due to their high spectral and energy efficiency and low hardware cost. Specifically, a reconfigurable intelligent surface is a planar array composed of a large number of reconfigurable passive elements (e.g., low-cost printed dipoles). Each circuit element in this planar array can independently generate a certain amplitude and / or phase shift under the control of an intelligent controller, thereby collectively changing the propagation of the reflected signal and achieving more directional three-dimensional reflected beamforming. Therefore, in future 5G / 6G wireless communication systems, reconfigurable smart surfaces can improve channel capacity, expand communication coverage, and reduce energy consumption.

[0003] However, passive reconfigurable smart surfaces can only reflect incident signals, meaning that users on the other side cannot receive service. To address this issue, intelligent omni-surface (IOS) was proposed (see: DoCoMo NT T. DOCOMO conducts world's first successful trial of transparent dynamic metasurface[J]. 2020.). Compared to RIS, it has the dual function of signal reflection and transmission, meaning that signals incident on the IOS can be simultaneously reflected and transmitted to receivers located on the same side and the other side of the IOS. Similar to RIS, by properly designing and controlling the IOS, the wireless transmission environment can be altered to provide 360° omnidirectional coverage.

[0004] However, due to the "double fading" effect (i.e., the signal received through the reflected link is affected by two large-scale attenuations; specifically, the equivalent path loss from the transmitter to the receiver via the RIS is the product of the path loss from the transmitter to the RIS and the path loss from the RIS to the receiver, rather than the sum, which is usually thousands of times greater than the loss of the direct link), passive reconfigurable smart surfaces are almost impossible to achieve significant capacity gains in typical wireless transmission environments where direct links exist (see reference: Najafi M, Jamali V, Schober R, et al. Physics-based modeling and scalable optimization of large intelligent reflecting surfaces[J].IEEE Transactions on Communications, 2020, 69(4):2673-2691). To overcome the physical limitations of the "double fading" effect, active reconfigurable smart surfaces have recently been proposed as a promising solution. They can significantly improve communication performance in typical communication scenarios (with a direct path). Similar to existing passive reconfigurable smart surfaces, active reconfigurable smart surfaces can also adjust the incident signal by controlling the adjustable phase. Unlike passive reconfigurable smart surfaces that only reflect the signal without amplifying it, active reconfigurable smart surfaces can further amplify the reflected signal through integrated active reflective amplifiers, such as current converters, asymmetric current mirrors, or some integrated chips. Although this structure can improve communication performance and has lower hardware complexity, it cannot solve the problem of service blind spots, that is, users located behind the active smart surface cannot be served. While amplify-relay relays can amplify and transmit signals, they typically require a bulky and power-intensive RF chain to receive the signal before amplification and transmission. This necessitates two time slots for amplification and relay processing. Operating in full-duplex mode significantly increases hardware complexity to reduce self-interference. Furthermore, amplify-relay relays directly amplify the received signal without phase correction; therefore, additional phase adjustment is required at the receiver in amplify-relay-assisted wireless communication system. Thus, designing an active reconfigurable smart surface that comprehensively improves communication performance for all users is essential. Summary of the Invention

[0005] This invention addresses the issues of insufficient gain and limited service range in existing passive reconfigurable smart surface beamforming systems, and provides a novel low-power, low-complexity active dual-function reconfigurable smart surface cell, comprising:

[0006] The incident electromagnetic signal is amplified to obtain an active load of the amplified electromagnetic signal;

[0007] Receive the amplified electromagnetic signal transmitted by the active load, perform power distribution on the amplified electromagnetic signal, and obtain a power distribution network for the power-distributed electromagnetic signal.

[0008] Receive the power-allocated electromagnetic signal transmitted by the power distribution network, perform phase modulation on the power-allocated electromagnetic signal, and output the first phase shifter of the modulated electromagnetic signal;

[0009] The system receives the power-distributed electromagnetic signal transmitted by the power distribution network, performs phase modulation on the power-distributed electromagnetic signal, and outputs a second phase shifter of the modulated electromagnetic signal.

[0010] Furthermore, it also includes a controller, which sends the amplification factor, power distribution factor and modulation phase determined by the receiver channel state information to the integrated amplifier, the power distribution network, the first phase shifter and the second phase shifter, respectively.

[0011] A novel low-power, low-complexity active dual-function reconfigurable smart surface includes M smart surface units as described above.

[0012] Furthermore, the intelligent surface unit is square, rectangular, circular, rhomboid, or triangular.

[0013] Furthermore: it includes a first smart surface RIS-1 and a second smart surface RIS-2; the first smart surface RIS-1 and the second smart surface RIS-2 are deployed in opposition to each other;

[0014] The first smart surface RIS-1 and the second smart surface RIS-2 have the same structure.

[0015] Furthermore: the M smart surface units are arranged in an array;

[0016] The amplified signal of the first smart surface RIS-1 reconfigurable smart surface is represented as follows:

[0017]

[0018] in: This represents the channel from the transmitter to the active dual-function reconfigurable smart surface.

[0019] v represents the input noise of the active smart surface and the thermal noise caused by the active smart surface; This represents the amplification factor matrix of an active dual-function reconfigurable smart surface.

[0020] This represents the amplification coefficient vector of an active dual-function reconfigurable smart surface;

[0021] The transmitted signal is represented as in, It is the signal transmitted from the transmitter to the k-th receiver, and satisfies... It is the beamforming of the transmitter to the k-th receiver.

[0022] A multi-user multiple-input single-output signal transmission system includes a transmitter, a receiver, and a dual-function reconfigurable smart surface;

[0023] The transmitting end transmits a signal, which passes through a channel to reach the dual-functional reconfigurable smart surface, where the dual-functional reconfigurable smart surface processes the signal.

[0024] The processed signal is then transmitted to the receiving end through the channel.

[0025] The objective function to maximize the overall rate of the system is as follows:

[0026]

[0027] The process of solving the objective equation for the total rate of the system is as follows:

[0028] S1: Transform the objective equation by introducing the auxiliary variable γ based on fractional programming theory. k and τ k This transforms the original problem into an equivalent form that is easier to solve.

[0029] S2: Update auxiliary variable γ k and τ k When other variables are given, taking the derivative of the objective function can yield the optimal solution for the auxiliary variables;

[0030] S3: Update transmitter beamforming: When all other variables are known, the optimization problem of transmitter beamforming is a convex optimization problem, which can be solved using the Lagrange multiplier method;

[0031] S4: Update the reflection coefficient matrix of the active reconfigurable smart surface by iteratively solving the reflection coefficient matrix based on the Riemannian manifold algorithm;

[0032] S5: Updating the magnification matrix is ​​a standard second-order cone optimization problem, and its optimal solution can be easily obtained using various existing optimization tools;

[0033] S6: After obtaining other optimization variables, iteratively design each element of the power allocation coefficient vector ζ until convergence.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The electromagnetic signal forwarding and amplification is achieved by using more economical and energy-efficient integrated amplifiers, impedance devices and other basic circuit elements, thereby providing sufficient channel gain and achieving ideal communication performance. At the same time, this circuit structure is very simple. The incident signal is amplified and distributed by basic circuit elements, and then phase-controlled and reflected / transmitted by phase shifters. This maximizes hardware efficiency and greatly reduces power consumption. The intelligent reconfigurable surface reduces the use of the radio frequency chain, so it can be densely deployed with low cost and low energy consumption.

[0036] By applying the technical solution of this invention, the number of components on the reconfigurable smart surface can be greatly reduced by adding an active load, thereby reducing hardware complexity and power consumption. This solves the problems of insufficient beamforming gain and limited service range of passive reconfigurable smart surfaces in existing transmission systems. By fully utilizing the flexibility and high degree of freedom of active reconfigurable smart surfaces, the communication coverage is expanded to achieve 360° all-round coverage, and the communication performance of all receiving users in the system is improved.

[0037] Due to its outstanding advantages such as low profile, lightweight design, and conformal geometry, intelligent reconfigurable surfaces can be easily installed / removed from building walls or ceilings. Furthermore, intelligent reflective surfaces can be practically manufactured to fit on surfaces of any shape to adapt to different application scenarios, thus offering high flexibility in practical deployment. By installing intelligent reconfigurable surfaces on walls / ceilings within the direct line-of-sight range of the access point / transmitter, the signal strength of receiving users can be significantly improved. Integrating intelligent reconfigurable surfaces into existing networks (such as cellular or WiFi) requires no changes to the hardware or software of the equipment, especially in high-user-density indoor applications (such as stadiums, shopping malls, exhibition centers, airports, etc.).

[0038] It should be noted that while the active dual-function reconfigurable smart surface proposed and researched can amplify the incident signal, it differs significantly from an amplification-retransmission relay in practice. The characteristics and hardware structure of the active dual-function reconfigurable smart surface are essentially the same as those of the traditional passive reconfigurable smart surface, except that the reconfigured passive load impedance is replaced with an active load impedance, and a power distribution network is added. Although the active dual-function reconfigurable smart surface requires additional power consumption to support its active load impedance, its basic operating mechanism remains the direct adjustment of the incident electromagnetic wave signal. Furthermore, the active dual-function reconfigurable smart surface not only amplifies the incident signal but can also readjust its phase, ensuring that the desired signals are superimposed in phase at the receiving end.

[0039] Because active intelligent reconfigurable surfaces have outstanding advantages such as low profile, lightweight and low cost, their practical deployment is highly flexible. They can be directly placed in any existing wireless communication system without any changes to the hardware and software of the device.

[0040] Due to the low cost, low power consumption, and easy installation characteristics of the active dual-function reconfigurable smart surface, this invention can be widely promoted in the field of wireless communication. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the active dual-functional reconfigurable smart surface structure of the present invention;

[0043] Figure 2 This is a flowchart of the algorithm for the joint design of transmitter beamforming and active smart surface in an embodiment of the present invention;

[0044] Figure 3 This is a simulation diagram comparing the transmission power with the total rate in this invention;

[0045] Figure 4 A simulation graph showing the number of active reconfigurable smart surface elements compared to the total rate;

[0046] Figure 5 A simulation graph comparing the user distribution with the total rate. Detailed Implementation

[0047] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. The following description of exemplary embodiments is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0048] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0049] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0050] This invention provides a novel low-power, low-complexity active dual-function reconfigurable smart surface unit for use in wireless communication systems, comprising an active load, a power distribution network, a first phase shifter, and a second phase shifter;

[0051] The active load amplifies the electromagnetic signal incident on the electromagnetic plane to obtain an amplified electromagnetic signal.

[0052] The power distribution network receives the amplified electromagnetic signal transmitted by the active load, performs power distribution on the amplified electromagnetic signal, and obtains the power-distributed electromagnetic signal.

[0053] The first phase shifter receives the power-divided electromagnetic signal transmitted by the power distribution network, performs phase modulation on the power-divided electromagnetic signal, and outputs the modulated electromagnetic signal as a reflected signal.

[0054] The second phase shifter receives the power-divided electromagnetic signal transmitted by the power distribution network, performs phase modulation on the power-divided electromagnetic signal, and outputs the modulated electromagnetic signal as a transmission signal.

[0055] The active load achieves electromagnetic signal forwarding and amplification through basic circuit elements such as integrated power amplifiers and impedance devices;

[0056] The dual-function reconfigurable smart surface unit is supported by a set of active load impedances. Using resistive elements such as tunnel diodes, it converts DC bias power into radio frequency power, amplifying the incident signal at the electromagnetic level without requiring complex and power-consuming radio frequency chain components. The signal power is shunted through a power distribution network composed of basic electromagnetic components, selecting the optimal power distribution coefficient. Compared to passive smart surfaces, active reconfigurable smart surfaces can directly reflect the incident signal and amplify it at the electromagnetic level. It still retains the advantages of low cost and low power consumption, as it does not require complex and power-consuming radio frequency chain components. In hardware circuit design, the active load can be implemented using resistive elements such as tunnel diodes to convert DC bias power into radio frequency power, thereby amplifying the incident signal without significantly violating low power budget requirements.

[0057] The first and second phase shifters are composed of basic electromagnetic components. By adjusting the parameters of the capacitor and inductor to adjust the resonant frequency, the phase of the reflected and transmitted signals is changed, and the phase of the signals is modulated to different degrees. Then, the signals are transmitted in parallel to the front and back, so that the desired signals are superimposed in phase at the receiving end, thereby improving the wireless communication performance of the receiving end.

[0058] The first phase shifter and the second phase shifter can be implemented using simple capacitors, inductors or resistors;

[0059] The number of integrated amplifiers, the number of power distribution networks, and the number of active dual-function reconfigurable smart surface elements are equal. The number of phase shifters is twice the number of active dual-function reconfigurable smart surface elements. That is, each dual-function reconfigurable smart surface unit integrates a reflective power amplifier, a power distribution network, and two phase shifters.

[0060] The dual-function reconfigurable smart surface unit also includes a controller, which sends the amplification factor, power distribution factor, and modulation phase determined by the receiver channel state information to the integrated amplifier, the power distribution network, the first phase shifter, and the second phase shifter, respectively.

[0061] There are currently two types of controllers: one is to connect a control device to the dual-function reconfigurable smart surface unit, and the other is to control it directly through a chip within the dual-function reconfigurable smart surface unit.

[0062] The amplification factor of the active reconfigurable smart surface integrated amplifier, the power distribution coefficient of the power distribution network, and the phase value of the corresponding phase shifter are adjusted according to the channel state information of the receiver. By amplifying the incident signal and readjusting its phase, the desired signal is superimposed in phase at the receiver to improve the wireless communication performance of the receiver.

[0063] A novel low-power, low-complexity active dual-functional reconfigurable smart surface includes M novel low-power, low-complexity active dual-functional reconfigurable smart surface units.

[0064] The smart surface unit can be square, rectangular, circular, rhomboid, or triangular.

[0065] The M smart surface units are arranged in an array. In the active dual-function reconfigurable smart surface structure, the number of components affects the beamforming gain. The more components there are, the greater the beamforming gain; the fewer components there are, the smaller the beamforming gain.

[0066] The reconfigurable smart surface includes a first smart surface RIS-1 and a second smart surface RIS-2; the first smart surface RIS-1 and the second smart surface RIS-2 are deployed in opposition to each other, therefore it is assumed that there are no cross-transmission signals, that is, the reflected signal and the transmitted signal do not affect each other.

[0067] The first smart surface RIS-1 and the second smart surface RIS-2 have the same structure;

[0068] Each face has M phase shifters that can be adjusted by the controller, defining the reflection phase shift vector. and reflection matrix in This represents the phase shift of the m-th element in the first intelligent surface RIS-1. and Let φa and φb represent the amplification coefficient vector and matrix of the active bifunctional reconfigurable smart surface. Similarly, let φ2 and φb represent the phase shift vector and matrix of the second smart surface RIS-2. The signal amplified by the active bifunctional reconfigurable smart surface can be expressed as:

[0069]

[0070] in denoted as the channel from the transmitter to the active dual-function reconfigurable smart surface, and v represents the input noise of the active smart surface and the thermal noise caused by the active smart surface.

[0071] The amplified signal is split into two parts, one of which is phase-shifted by a phase shifter and reflected back to the receiver.

[0072] The power allocation factor at this time is:

[0073]

[0074] Another portion of the signal is also transmitted to the receiving end via phase shifter. The power allocation factor for this part is:

[0075]

[0076] By jointly designing beamforming at the transmitter, the amplification gain matrix, phase shift matrix, and power distribution coefficient matrix of the active dual-function reconfigurable smart surface are used to achieve reflection and transmission functions, improve the communication performance of all receivers, and maximize the overall system rate.

[0077] Compared to amplify-relay relays, active dual-function reconfigurable smart surfaces do not require expensive and power-consuming RF chains to receive signals first and then amplify and transmit them. The basic operating mechanism is to directly adjust the incident electromagnetic wave signal. The amplification, distribution, reflection / transmission of the signal are performed simultaneously without introducing additional time delay. In addition, active dual-function reconfigurable smart surfaces can readjust the phase of the incident signal so that the desired signals are superimposed in phase at the receiving end, while amplify-relay relays directly amplify the received signal without phase correction, requiring additional phase adjustment at the receiving end.

[0078] Each reconfigurable element is supported by a set of active load impedances. Using resistive elements such as tunnel diodes, DC bias power is converted into RF power, amplifying the incident signal at the electromagnetic level without requiring complex and power-consuming RF chain components. The signal power is split through a power distribution network composed of basic electromagnetic elements, selecting the optimal power distribution coefficient. Finally, the signal phase is modulated to different degrees by two phase shifters composed of corresponding basic electromagnetic elements, and then transmitted in parallel forward and backward, ensuring that the desired signals are superimposed in phase at the receiving end to improve the wireless communication performance at the receiving end. The specific advantages of this active dual-function reconfigurable smart surface system architecture based on basic electromagnetic elements are mainly reflected in the following aspects: the required circuit components are simple, the implementation is simpler than traditional repeater-amplifier relays, and the power consumption is also very low. Figure 1 As shown, traditional passive smart reflectors may suffer from resonance loss (the amplitude response is not constant at different frequencies). Therefore, in broadband communication systems, active load impedance based on tunnel diodes can be used to provide gain compensation for signal attenuation at different amplitudes, thereby improving the resonance loss problem. Finally, it is worth mentioning that experiments have shown that a DC power consumption of 45μW can typically support a power gain of 40dB, while the power distribution network and phase shifter composed of basic electromagnetic components consume no power. Therefore, the structure proposed in this invention has very low overall energy consumption and low hardware complexity.

[0079] The present invention also provides a signal transmission system using the above-mentioned novel active dual-function reconfigurable smart surface, including a transmitter, a receiver and the reconfigurable smart surface.

[0080] The transmitting end transmits a signal, and the transmitting end can be a base station;

[0081] The transmitted signal travels through a channel to a dual-functional reconfigurable smart surface, where the signal is processed.

[0082] The processed signal is then transmitted to the receiving end through the channel, and the receiving end may be a user;

[0083] The amplification factor of the active reconfigurable smart surface integrated amplifier, the power distribution coefficient of the power distribution network, and the phase value of the corresponding phase shifter are adjusted according to the channel state information of the receiver. By amplifying the incident signal and readjusting its phase, the desired signal is superimposed in phase at the receiver to improve the wireless communication performance of the receiver.

[0084] Example 1

[0085] The technical solution of the present invention will be further explained below using the design of an active dual-function reconfigurable smart surface-assisted wireless communication system as an example.

[0086] Taking a multi-user multiple-input single-output wireless communication system as an example, the wireless communication system structure assisted by an active reconfigurable smart surface with dual functions of reflection and transmission described in this invention is used. The transmitter equipped with N antennas communicates with K single-antenna receivers via a dual-function active reconfigurable smart surface. The receivers are aggregated using a set of... express;

[0087] Some receivers are located around the active reconfigurable smart surface, and are provided by the side facing them (denoted as RIS-1). Meanwhile, other receivers, located on the back side of the active reconfigurable smart surface, have their direct link to the transmitter blocked and cannot receive sufficiently strong signals reflected from the transmitter or RIS-1, resulting in poor communication service quality. The set of receivers receiving reflected signals from the first smart surface RIS-1 is designated as... This indicates that the set of receivers that receive transmitted signals from the second smart surface RIS-2 is used for... Indicate, and satisfy

[0088] The dual-function active reconfigurable smart surface has M reconfigurable elements that can be adjusted by a controller, defining a reflection coefficient vector. and reflection matrix in This represents the phase shift of the m-th element in the RIS-1 smart surface. and Let φ2 and Φ2 represent the amplification factor vector and matrix of the active smart surface. Similarly, let φ2 and Φ2 represent the phase shift vector and matrix of RIS-2.

[0089] The transmitted signal at the transmitting end can be represented as in, It is the signal transmitted from the transmitter to the k-th receiver, and satisfies... It is the beamforming of the transmitter to the k-th receiver.

[0090] The signal amplified by the active reconfigurable smart surface can be represented as:

[0091]

[0092] in This represents the channel from the transmitter to the active smart surface, where v represents the input noise and the resulting thermal noise of the active smart surface.

[0093] The amplified signal is split into two parts, one of which is angle-modulated and reflected back to the receiver. The power allocation factor is:

[0094]

[0095] The other part of the signal is also transmitted to the receiving end via angle modulation. The power allocation factor is:

[0096]

[0097] For the k-th receiver Serviced by the first intelligent surface RIS-1, the signals received by these receivers can be represented as:

[0098]

[0099] in: and Let represent the channels from the transmitter to the k-th receiver and from the active smart surface to the k-th receiver, respectively. This indicates that the variance received by the k-th receiver is... Given the additive white Gaussian noise, the signal-to-interference-plus-noiseratio (SINR) of the k-th receiver located in the reflection region can be expressed as:

[0100]

[0101] in This represents the equivalent channel from the transmitter to the k-th receiver.

[0102] For the receiver located on the back of a dual-function active reconfigurable smart surface, the transmitter-to-reset signal is significantly reduced due to the smart surface's obstruction and severe path attenuation. The receiving end in the middle does not have a direct link, therefore, it is located in The signal-to-interference-plus-noise ratio (SINR) of the signal received by the k-th receiver can be expressed as:

[0103]

[0104] in: Indicates from the transmitter to The equivalent channel of the k-th receiver in the diagram;

[0105] Based on the aforementioned reflection-transmission dual-function active reconfigurable smart surface-assisted multi-receiver wireless communication system, beamforming at the transmitter is jointly designed. k , Given the amplification gain matrix A, phase shift matrices Φ1, Φ2, and power distribution coefficient matrices E1, E2 of the active smart surface, maximize the overall system speed while considering the following constraints:

[0106] (1) Transmitter power limitation, i.e. P T This represents the maximum transmission power of the transmitter.

[0107] (2) Power limitations of active reconfigurable smart surface amplification, i.e. P R This represents the maximum amplification power of an active reconfigurable smart surface.

[0108] (3) Power amplification limit for each element in an active smart surface, i.e. in This represents the equivalent channel from the transmitter to the m-th element of the active smart surface, which is also the m-th row of matrix G, P m For the maximum power limit of the m-th element of the active reconfigurable smart surface (and due to the thermal load of the circuit, P) m satisfy );

[0109] (4) Power ratio constraint between reflection and transmission, i.e.

[0110] (5) The restriction that the phase shift mode is one, i.e., |φ1(m)|=1, |φ2(m)|=1,

[0111] Therefore, the objective equation can be expressed in the following form:

[0112]

[0113] Clearly, this optimization problem is non-convex, and due to the one-module constraint and the coupling between variables, it is difficult to solve directly.

[0114] Therefore, this paper proposes a solution with local optima for the above problem. Specifically, a block coordinate ascent method is used to iteratively update each variable, and the transmitter beamforming, active reconfigurable smart surface magnification, phase shift matrix, and power allocation matrix are solved iteratively. The flowchart is as follows. Figure 2 As shown, the steps are as follows:

[0115] S1: Transform the objective equation by introducing the auxiliary variable γ based on fractional programming theory. k and τ k This transforms the original problem into an equivalent form that is easier to solve.

[0116] S2: Update auxiliary variable γ k and τ k When other variables are given, taking the derivative of the objective function can yield the optimal solution for the auxiliary variables;

[0117] S3: Update transmitter beamforming: When all other variables are known, the optimization problem of transmitter beamforming is a convex optimization problem, which can be solved using the Lagrange multiplier method;

[0118] S4: Update the reflection coefficient matrix of the active reconfigurable smart surface by iteratively solving the reflection coefficient matrix based on the Riemannian manifold algorithm;

[0119] S5: Updating the magnification matrix is ​​a standard second-order cone optimization problem, and its optimal solution can be easily obtained using various existing optimization tools (such as CVX).

[0120] S6: After obtaining other optimization variables, we... (The sentence is incomplete and requires more context to translate accurately.) The design is iterated for each element until convergence. Convergence is determined by the fact that the value of the objective equation remains essentially unchanged.

[0121] Figure 3 This is a simulation diagram comparing the transmission power with the total rate in this invention;

[0122] Figure 4 A simulation graph showing the number of active reconfigurable smart surface elements compared to the total rate;

[0123] Figure 5 The simulation graph compares the total rate with the user distribution. Based on the architecture proposed in this invention, the active dual-function reconfigurable smart surface can always achieve better communication performance.

[0124] And from Figure 5 The simulation results show that the architecture proposed in this invention has significant advantages for any distribution of the receiving end.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel low-power, low-complexity active dual-function reconfigurable smart surface unit, characterized in that, include: The incident electromagnetic signal is amplified to obtain an active load of the amplified electromagnetic signal; Receive the amplified electromagnetic signal transmitted by the active load, perform power distribution on the amplified electromagnetic signal, and obtain a power distribution network for the power-distributed electromagnetic signal. Receive the power-allocated electromagnetic signal transmitted by the power distribution network, perform phase modulation on the power-allocated electromagnetic signal, and output the first phase shifter of the modulated electromagnetic signal; The system receives the power-distributed electromagnetic signal transmitted by the power distribution network, performs phase modulation on the power-distributed electromagnetic signal, and outputs a second phase shifter of the modulated electromagnetic signal.

2. The novel low-power, low-complexity active dual-function reconfigurable smart surface unit according to claim 1, characterized in that, It also includes the controller, The controller sends the amplification factor, power distribution factor, and modulation phase determined by the receiver channel state information to the integrated amplifier, the power distribution network, the first phase shifter, and the second phase shifter, respectively.

3. A novel low-power, low-complexity active dual-function reconfigurable smart surface, characterized in that: include A smart surface unit as described in any one of claims 1-2.

4. A novel low-power, low-complexity active dual-function reconfigurable smart surface according to claim 3, characterized in that: The smart surface unit can be square, rectangular, circular, rhomboid, or triangular.

5. A novel low-power, low-complexity active dual-function reconfigurable smart surface according to claim 3, characterized in that: It includes a first smart surface RIS-1 and a second smart surface RIS-2; the first smart surface RIS-1 and the second smart surface RIS-2 are deployed in opposition to each other; The first smart surface RIS-1 and the second smart surface RIS-2 have the same structure.

6. A novel low-power, low-complexity active dual-functional reconfigurable smart surface according to claim 5, characterized in that: The The intelligent surface units are arranged in an array; The amplified signal of the first smart surface RIS-1 reconfigurable smart surface is represented as follows: （1） in: This represents the channel from the transmitter to the active dual-function reconfigurable smart surface. This represents the input noise of the active smart surface and the thermal noise caused by the active smart surface. This represents the amplification factor matrix of an active dual-function reconfigurable smart surface. This represents the amplification coefficient vector of an active dual-function reconfigurable smart surface; The transmitted signal is represented as in, It is the transmitter to the first The transmitted signal of each receiving end, and satisfies , It is the transmitter to the first Beamforming at each receiver.

7. A multi-user multiple-input single-output signal transmission system, characterized in that: Includes a transmitter, a receiver, and a dual-function reconfigurable smart surface as described in claims 3-5; The transmitter transmits a signal. The transmitted signal travels through a channel to a dual-functional reconfigurable smart surface, where the signal is processed. The processed signal is then transmitted to the receiving end through the channel.

8. A multi-user multiple-input single-output signal transmission system according to claim 7, characterized in that: The objective function to maximize the overall rate of the system is as follows: （10） The process of solving the objective equation for the total rate of the system is as follows: S1: Transform the objective equation by introducing auxiliary variables based on fractional programming theory. and This transforms the original problem into an equivalent form that is easier to solve. S2: Update auxiliary variables and When other variables are given, taking the derivative of the objective function can yield the optimal solution for the auxiliary variables; S3: Update transmitter beamforming: When all other variables are known, the optimization problem of transmitter beamforming is a convex optimization problem, which can be solved using the Lagrange multiplier method; S4: Update the reflection coefficient matrix of the active reconfigurable smart surface by iteratively solving the reflection coefficient matrix based on the Riemannian manifold algorithm; S5: Updating the magnification matrix is ​​a standard second-order cone optimization problem, and its optimal solution can be easily obtained using various existing optimization tools; S6: After obtaining other optimization variables, the power allocation coefficient vector Iterate through each element of the design until convergence.

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