A reconfigurable intelligent metasurface beam tracking device

Abstract

The present invention discloses a reconfigurable intelligent metasurface beam tracking device, belonging to the field of wireless communication technology. Specifically, the reconfigurable intelligent metasurface module integrates a large number of metasurface units and embeds tunable elements to achieve reconfigurable electromagnetic characteristics. The receiving end of the communication transceiver module receives the reflected signal from the metasurface during movement and provides feedback on the received signal quality. The positioning perception module senses the receiving end's position in real time. The codebook calculation module calculates the phase control codebook based on the signal quality and position feedback information, converts it into a control voltage value, and transmits the corresponding digital control signal to the voltage control module, which outputs multiple analog voltages to regulate the reflection coefficient of the metasurface array and achieve real-time dynamic beam tracking. The present invention significantly improves the coverage, transmission rate, and service quality of the communication network.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a reconfigurable intelligent metasurface beam tracking device. Background Art

[0002] Reconfigurable Intelligent Surface (RIS) technology is a cutting-edge technology attracting widespread attention in the field of wireless communications, showing great potential in sixth-generation (6G) wireless communication networks. RIS integrates a large number of reflective elements to achieve programmable electromagnetic wave control, providing a more flexible and efficient solution for wireless communications.

[0003] However, in RIS-assisted mobile communication scenarios, beam tracking accuracy becomes a significant challenge as users move and the environment changes. While existing RIS can adjust the direction of the beam to a certain extent, the sheer number of reflectors in the RIS significantly increases the complexity and computational effort of beam steering, leading to significant technical hurdles for existing systems in mobile scenarios.

[0004] Furthermore, beam tracking requires not only highly sensitive control capabilities but also the ability to detect changes in the user's position in real time to quickly adjust the beam. However, existing technologies are limited in positioning and tracking capabilities, lacking real-time perception and rapid response mechanisms. This makes it difficult for existing systems to achieve efficient beam tracking in scenarios where the user is moving.

[0005] Therefore, there are still large technical gaps in the existing system, and new solutions are urgently needed to address the complexity of beam steering and the real-time problems of beam tracking, so as to provide more reliable support for the application and development of 6G networks. Summary of the Invention

[0006] The present invention proposes a reconfigurable intelligent metasurface beam tracking device. When the user moves arbitrarily, by building a signal feedback link, based on real-time perception and positioning, the metasurface control codebook is adaptively and rapidly iterated, enabling the system to achieve arbitrary beam tracking in complex electromagnetic environments, significantly improving the coverage, transmission rate and service quality of the communication network.

[0007] The reconfigurable intelligent metasurface beam tracking device includes: a reconfigurable intelligent metasurface module, a communication transceiver module, a signal feedback module, a codebook calculation module, a voltage control module and a positioning perception module;

[0008] The reconfigurable intelligent metasurface module includes a plurality of metasurface units arranged in a periodic manner to form a two-dimensional array. The metasurface units realize reconfigurable electromagnetic properties by integrating tunable elements. The tunable elements are varactor diodes, and phase reconfiguration is achieved by changing the reverse bias voltage of the varactor diodes.

[0009] The communication transceiver module includes a transmitting end and a receiving end. The transmitting end excites the transmission signal to the reconfigurable intelligent metasurface module, and the receiving end receives the reflected signal from the reconfigurable intelligent metasurface module and sends the received signal quality information to the signal feedback module.

[0010] The signal feedback module transmits the receiving end position and the received signal quality information to the codebook calculation module;

[0011] The codebook calculation module calculates the phase control codebook of the reconfigurable intelligent metasurface module according to the data fed back by the signal feedback module, converts it into a corresponding control voltage value, and transmits the digital signal corresponding to the voltage value to the voltage control module;

[0012] The voltage control module is used to output multiple independent voltage signals, and each voltage signal is output to a corresponding metasurface unit;

[0013] The positioning sensing module is used to sense the position information of the receiving end and send the position information of the receiving end to the signal feedback module;

[0014] Furthermore, the codebook calculation module executes a codebook adaptive iterative algorithm based on the feedback information to calculate a phase codebook, specifically:

[0015] 1) When the feedback information is the receiving end position, the codebook adaptive iterative algorithm directly calculates the reflection phase of each unit based on the position information:

[0016]

[0017] Where k represents the number of electromagnetic waves in space, d x and d y Denote the size of the metasurface unit in the x-axis and y-axis, d i,j represents the distance from the feed source to the metasurface unit with coordinates (i, j), is the azimuth angle of the receiving end relative to the metasurface unit, θ is the pitch angle of the receiving end relative to the metasurface unit;

[0018] 2) For feedback information of the received signal quality at the receiving end, the codebook adaptive iterative algorithm searches the codebook based on the received signal quality at the receiving end. The reflection phase of each metasurface unit is divided into three parts:

[0019] Φ d =kd i,jIt only depends on the geometric relationship between the feed source and the metasurface unit and is a fixed value;

[0020] Reflects the phase gradient in the horizontal direction;

[0021] Reflects the phase gradient in the vertical direction;

[0022] The compensation phase of the metasurface unit is represented as the superposition of the horizontal phase gradient and the vertical phase gradient;

[0023] To further reduce the complexity of codebook search, in the two-dimensional array of reconfigurable smart metasurface modules, reflective units in the same row share a horizontal phase gradient, and reflective units in the same column share a vertical phase gradient. Phase iteration logic is performed by updating the phase gradients of each row and column.

[0024] Furthermore, the positioning perception module includes a positioning transmitting antenna, a positioning receiving antenna and a signal processing device, wherein the positioning transmitting antenna and the receiving antenna are respectively connected to the signal processing device, the signal processing device controls the positioning transmitting antenna to transmit a signal, and estimates the position of the positioning transmitting antenna according to the received signal of the positioning receiving antenna based on the phase configuration information of the metasurface unit and the position and direction of the positioning receiving antenna relative to the metasurface unit;

[0025] For feedback information that is the quality of the received signal at the receiving end, the workflow of the reconfigurable intelligent metasurface beam tracking device is as follows:

[0026] Step 1: The transmitter in the communication transceiver module transmits a signal. When the receiver moves at any time, the positioning transmitting antenna in the positioning sensing module follows the receiver and transmits a positioning signal in real time.

[0027] Step 2: The positioning receiving antenna in the positioning sensing module receives the positioning signal from the positioning transmitting antenna, obtains the real-time position information of the receiving end after signal processing, and sends the position signal to the signal feedback module;

[0028] Step 3: The signal feedback module further feeds back the position information of the receiving end to the codebook calculation module;

[0029] Step 4: The codebook calculation module calculates the reflection coefficient of the metasurface array based on the position information of the receiving end, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface module, and transmits the digital control signal corresponding to the voltage value to the voltage control module;

[0030] Step 5: The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, changing the phase gradient of the metasurface array, thereby reflecting the signal from the transmitting end to the location of the receiving end, realizing real-time dynamic beam tracking, and the reflected signal moves together with the receiving end.

[0031] For feedback information that is the receiving end position, another workflow of the reconfigurable intelligent metasurface beam tracking device is as follows:

[0032] Step 1: The codebook calculation module initializes the reflection coefficient of the metasurface array, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface, and transmits the digital control signal corresponding to the voltage value to the voltage control module;

[0033] Step 2: The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, thereby changing the phase gradient of the metasurface array;

[0034] Step 3: The transmitter in the communication transceiver module transmits a signal, and the reconfigurable metasurface module reflects the incident signal from the transmitter to the receiver. When the receiver moves arbitrarily, the quality information of the received signal is fed back to the signal feedback module.

[0035] Step 4: The signal feedback module further feeds back the received signal quality information of the receiving end to the codebook calculation module;

[0036] Step 5: The codebook calculation module determines whether the received signal quality reaches the threshold. If so, the receiving end and the transmitting end communicate normally, realizing real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the received signal quality until the received signal quality at the receiving end reaches the threshold.

[0037] The phase iteration logic includes:

[0038] (1) First, the phase gradient of the metasurface array is randomly initialized to evaluate the radiation pattern and obtain the received signal quality at the receiving end;

[0039] (2) Randomly select a row or column of the metasurface array, change the phase gradient, continue to evaluate the radiation pattern, and obtain the received signal quality at the receiving end;

[0040] (3) Determine whether the quality of the received signal at the receiving end is greater than the quality of the received signal in the previous iteration. If so, fix the phase gradient change of the row or column; otherwise, discard the phase gradient change of the row or column and repeat (2);

[0041] The advantages of the present invention are:

[0042] 1. The present invention discloses a reconfigurable intelligent metasurface beam tracking device. The designed metasurface unit structure realizes phase reconfiguration based on varactor diodes, has a simple structure, and is easy to integrate and implement.

[0043] 2. The present invention provides a reconfigurable intelligent metasurface beam tracking device. The designed metasurface-assisted positioning solution is highly scalable and can be easily integrated with existing metasurface systems.

[0044] 3. The present invention provides a reconfigurable intelligent metasurface beam tracking device. The designed metasurface codebook adaptive iteration scheme can adaptively and intelligently adjust the metasurface coefficients in different environments.

[0045] 4. The present invention provides a reconfigurable intelligent metasurface beam tracking device and a designed beam tracking system that can realize beam tracking in a variety of environments without the need for human control and is flexible and versatile. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a block diagram of a reconfigurable intelligent metasurface beam tracking device according to the present invention;

[0047] Figure 2 Schematic diagram of calculation of the reflection coefficient of the reconfigurable intelligent metasurface of the present invention;

[0048] Figure 3 Schematic diagram of the adaptive phase iteration algorithm of the reconfigurable intelligent metasurface of the present invention;

[0049] Figure 4 is a three-dimensional view of a reconfigurable intelligent metasurface unit according to an embodiment of the present invention;

[0050] Figure 5 is a top view of a reconfigurable intelligent metasurface unit according to an embodiment of the present invention;

[0051] Figure 6 is a phase change diagram of the reconfigurable intelligent metasurface under different voltages within the working bandwidth according to an embodiment of the present invention;

[0052] Figure 7 is a structural diagram of a voltage control module used in an embodiment of the present invention;

[0053] Figure 8 This is a schematic diagram of the working logic of the positioning perception module used in an embodiment of the present invention;

[0054] Figure 9 This is a structural block diagram of the communication transceiver module used in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present invention will be further described below with reference to specific drawings and embodiments.

[0056] The present invention discloses a reconfigurable intelligent metasurface beam tracking device, such as Figure 1 As shown, it includes: a reconfigurable intelligent metasurface module, a communication transceiver module, a signal feedback module, a codebook calculation module, a voltage control module and a positioning perception module;

[0057] The reconfigurable intelligent metasurface module comprises a plurality of metasurface units arranged in a periodic manner to form a two-dimensional array. The metasurface units are integrated with tunable elements to achieve reconfigurable electromagnetic properties. The tunable elements are varactor diodes, and phase reconfiguration is achieved by changing the reverse bias voltage of the varactor diodes.

[0058] The communication transceiver module includes a transmitting end and a receiving end. The transmitting end excites the transmission signal to the reconfigurable intelligent metasurface module, and the receiving end receives the reflected signal from the reconfigurable intelligent metasurface module and sends the received signal quality information to the signal feedback module.

[0059] The signal feedback module collects the receiving end position information and the received signal quality information, and transmits them to the codebook calculation module;

[0060] The codebook calculation module calculates the phase control codebook of the reconfigurable intelligent metasurface module, i.e., the control coefficient, based on the data fed back by the signal feedback module, converts it into a corresponding control voltage value, and transmits the digital control signal corresponding to the voltage value to the voltage control module;

[0061] The voltage control module receives the digital control signal from the codebook calculation module and converts the digital control signal into multiple independent analog voltage signals, each of which is output to a corresponding metasurface unit;

[0062] The positioning sensing module is used to sense the position information of the receiving end and send the position of the receiving end to the signal feedback module;

[0063] Furthermore, the codebook calculation module executes a codebook adaptive iterative algorithm based on the feedback information to calculate a phase codebook, specifically:

[0064] 1) When the feedback information is the receiving end position, such as Figure 2 As shown in Figure 2, the codebook adaptive iterative algorithm directly calculates the reflection phase of each unit based on the position information:

[0065]

[0066] Where k represents the number of electromagnetic waves in space, d x and d y Denote the size of the metasurface unit in the x-axis and y-axis, d i,j represents the distance from the feed source to the metasurface unit with coordinates (i, j), is the azimuth angle of the receiving end relative to the metasurface unit, θ is the elevation angle of the receiving end relative to the metasurface unit;

[0067] 2) When the feedback information is the received signal quality at the receiving end, the codebook adaptive iterative algorithm searches the codebook based on the received signal quality at the receiving end. The reflection phase of each metasurface unit is divided into three parts:

[0068] Φ d =kd i,j It only depends on the geometric relationship between the feed source and the metasurface unit and is a fixed value;

[0069] Reflects the phase gradient in the horizontal direction;

[0070] Reflects the phase gradient in the vertical direction;

[0071] The compensation phase of the metasurface unit is represented as the superposition of the horizontal phase gradient and the vertical phase gradient;

[0072] To further reduce the complexity of phase codebook search, in the two-dimensional array of reconfigurable smart metasurface modules, reflective units in the same row share a horizontal phase gradient, and reflective units in the same column share a vertical phase gradient. Phase iteration logic is performed by updating the phase gradients of each row and column.

[0073] Furthermore, the positioning perception module includes a positioning transmitting antenna, a positioning receiving antenna and a signal processing device, wherein the positioning transmitting antenna and the receiving antenna are respectively connected to the signal processing device, the signal processing device controls the positioning transmitting antenna to transmit a signal, and estimates the position of the positioning transmitting antenna according to the received signal of the positioning receiving antenna based on the phase configuration information of the metasurface unit and the position and direction of the positioning receiving antenna relative to the metasurface unit;

[0074] When the feedback information is the receiving end position, the workflow of the reconfigurable intelligent metasurface beam tracking device is as follows:

[0075] Step 1: The transmitter in the communication transceiver module transmits a signal. When the receiver moves at any time, the positioning transmitting antenna in the positioning sensing module follows the receiver and transmits a positioning signal in real time.

[0076] Step 2: The positioning receiving antenna in the positioning sensing module receives the positioning signal from the positioning transmitting antenna, obtains the real-time position information of the receiving end after signal processing, and sends the position signal to the signal feedback module;

[0077] Step 3: The signal feedback module further feeds back the position information of the receiving end to the codebook calculation module;

[0078] Step 4: The codebook calculation module calculates the reflection coefficient of the metasurface array based on the position information of the receiving end, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface, and transmits the digital control signal corresponding to the voltage value to the voltage control module;

[0079] Step 5. The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, thereby changing the reflection coefficient of the metasurface array and reflecting the signal from the transmitting end to the location of the receiving end, so that the reflected signal moves with the receiving end and performs real-time dynamic beam tracking.

[0080] For feedback information that is the quality of a received signal at a receiving end, another workflow of the reconfigurable intelligent metasurface beam tracking device is as follows:

[0081] Step 1: The codebook calculation module initializes the reflection coefficient of the metasurface array, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface, and transmits the digital control signal corresponding to the voltage value to the voltage control module;

[0082] Step 2: The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, thereby changing the phase gradient of the metasurface array;

[0083] Step 3: The transmitter in the communication transceiver module transmits a signal, and the reconfigurable metasurface module reflects the incident signal from the transmitter to the receiver. When the receiver moves at any time, it receives signal quality information and sends it to the signal feedback module.

[0084] Step 4: The signal feedback module further feeds back the received signal quality information of the receiving end to the codebook calculation module;

[0085] Step 5: The codebook calculation module determines whether the received signal quality reaches the threshold. If so, the receiving end and the transmitting end communicate normally, realizing real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the received signal quality until the received signal quality at the receiving end reaches the threshold.

[0086] The phase iteration logic includes:

[0087] (4) First, the phase gradient of the metasurface array is randomly initialized, the radiation pattern of the metasurface array is evaluated, and the received signal quality at the receiving end is obtained;

[0088] (5) Randomly select a row or column of the metasurface array, change the phase gradient, continue to evaluate the radiation pattern, and obtain the received signal quality at the receiving end;

[0089] (6) Determine whether the quality of the received signal at the receiving end is greater than the quality of the received signal in the previous iteration. If so, fix the phase gradient change of the row or column; otherwise, discard the phase gradient change of the row or column and repeat (2);

[0090] Since the entire row or column shares the same phase gradient, the rank of the metasurface phase matrix is ​​reduced, resulting in a small amount of information loss and a slight increase in the beam sidelobes, which does not affect its application in actual systems.

[0091] At this time, for an M×N unit metasurface array, the coefficient calculation complexity is reduced from M×N to M+N, and the iterative process is as follows: Figure 3 shown.

[0092] Example:

[0093] The reconfigurable metasurface unit selected in this embodiment includes a substrate material, a resonant structure, a reconfigurable element, a feeder circuit and a packaging layer, wherein: the substrate material is the supporting structure of the metasurface unit; the resonant structure is used to interact with electromagnetic waves to achieve specified electromagnetic characteristics; the reconfigurable element is used to dynamically adjust the electromagnetic response of the metasurface; the feeder circuit is used to drive the reconfigurable element to achieve dynamic adjustment; and the packaging layer is used to protect the metasurface unit from environmental influences.

[0094] The electromagnetic control principle of reconfigurable metasurface units is as follows: by arranging resonant units of specific shapes and sizes on a substrate material, these units resonate with the incident electromagnetic wave, thereby controlling the amplitude and phase characteristics of the wave. By introducing controllable devices, the electromagnetic response of the resonant units can be dynamically changed, achieving real-time control of the electromagnetic wave.

[0095] like Figure 4 As shown, the metasurface unit comprises two layers of dielectric substrates and three layers of copper metal patches, wherein:

[0096] The dielectric substrate is made of F4B material, with a dielectric constant of ε r The dielectric constant is 2.65, the thickness is h1 = 3mm, h2 = 0.1mm, and 0.05mm Prepreg material is used for bonding in the middle. r =2.5;

[0097] The top metal patch is an I-shaped copper patch. Its induced electric field appears in the gap between the two microstrip patches, equivalent to a chip capacitor. High-frequency current flows back and forth between the capacitor gap, equivalent to the series connection of effective inductive impedance and resistance, reflecting a significant single-resonant electromagnetic response. A MAVR-000020-1411P varactor diode is loaded in the middle. This GaAs tuning diode provides broadband performance from 10 MHz to 70 GHz and is used to change the surface current distribution at different locations on the metal patch, thereby achieving reconfigurable characteristics.

[0098] The middle metal patch introduces an additional resonant meandering metal layer, which is equivalent to a series resonance model; the bottom metal patch serves as a metal backplane to improve the reflectivity of electromagnetic waves.

[0099] like Figure 5 The figure shows a top view of the metasurface unit of this example. The structural dimensions of the metasurface unit are shown in Table 1:

[0100] Table 1

[0101]

[0102] By applying different reverse bias voltages through the varactor diode integrated in the top metal patch, the metasurface achieves different phase responses, such as Figure 6 shown.

[0103] The voltage control module includes a data register, a multi-channel digital-to-analog conversion circuit and several output buffers, such as Figure 7 As shown, the data register is used to temporarily store the voltage information that needs to be applied to the metasurface unit; the digital-to-analog conversion circuit receives the digital voltage information from the data register and converts it into an analog voltage signal. Each data register corresponds to an independent DAC channel, ensuring that multiple voltage values ​​can be processed in parallel; the buffer provides the necessary current driving capability and stabilizes the output voltage to ensure that the voltage applied to the resonant unit is accurate.

[0104] Specifically, data registers can be written to using a microcontroller (MCU) or field programmable gate array (FPGA). The microcontroller receives voltage commands from a host computer or control software and writes these commands digitally into the data registers. The digital-to-analog conversion circuit can be a T-type conversion circuit consisting of a resistor network, an operational amplifier, a reference power supply, and an analog switch.

[0105] The codebook calculation module is used to execute an adaptive iterative algorithm based on feedback information to calculate the optimal codebook, convert these codebooks into corresponding control voltages, and finally send them to the voltage regulation module through the I / O port to control the electromagnetic response of the reconfigurable metasurface unit.

[0106] Specifically, the codebook calculation module can be implemented by high-performance programmable devices, including digital signal processing (Digital Signal Processing) chips, FPGAs, and embedded central processing units (CPUs), which are responsible for executing the adaptive iterative algorithm.

[0107] The principle of codebook calculation is to control the phase of the electromagnetic wave by providing a bias voltage to the varactor diode. The equivalent load impedance of the reflection unit changes with the change of capacitance. The reflection coefficient is a parameter used to indicate the amount of reflection generated on the surface of a medium with impedance discontinuity. It is equal to the ratio of the amplitude of the reflected wave to the amplitude of the incident wave. In this example, the reflection coefficient is determined by the equivalent load impedance of the reflection unit and the characteristic impedance of the air in the system:

[0108]

[0109] Where Z1 is the unit equivalent load impedance and Z0 is the characteristic impedance of air. Therefore, the phase adjustment of the reflector unit is:

[0110]

[0111] By adjusting the external bias voltage of the variable capacitance diode junction capacitance in the reflection unit, the coefficient of each reflection unit can be dynamically controlled.

[0112] The signal feedback module transmits the received signal quality and position information of the receiving end to the codebook calculation module through a wireless transmission link to optimize and adjust the response of the reconfigurable metasurface unit.

[0113] Specifically, the signal feedback module is connected to the receiving end of the communication transceiver module to obtain the received signal quality in real time. The received signal quality includes the received signal power and the received signal-to-noise ratio.

[0114] Specifically, the signal feedback module is connected to the positioning perception module to obtain the position information of the receiving end, which includes the direction angle and distance of the receiving end relative to the metasurface.

[0115] Specifically, the wireless transmission link uses a WiFi module for wireless transmission. WiFi modules provide a stable communication link, support high-bandwidth data transmission, and are easy to integrate. The WiFi module establishes a communication connection between the receiving end and the codebook calculation module and transmits data packets to the codebook calculation module via UDP or TCP / IP protocols. The data packets contain important feedback information such as received signal power, signal-to-noise ratio, and location information.

[0116] The positioning perception module is as follows Figure 8 As shown in the figure, high-precision positioning is achieved by using the phase configuration of a metasurface structure and a Universal Software Radio Peripheral (USRP). The positioning perception module includes a positioning transmitting antenna, a positioning receiving antenna, and a USRP signal processing device. The positioning transmitting antenna and receiving antenna are respectively connected to the USRP signal processing device. The USRP controls the positioning transmitting antenna to transmit signals and estimates the positioning transmitting antenna's position based on the received signals.

[0117] The positioning transmit antenna is connected to the USRP signal processing unit and transmits positioning signals. Positioning transmit antennas include omnidirectional and directional antennas, depending on the application scenario. The transmit antenna can transmit narrowband or broadband signals to support positioning requirements of varying resolutions. The USRP controls the transmit antenna's signal parameters, including frequency, power, and modulation.

[0118] The positioning receiving antenna is connected to the USRP signal processing unit to receive the positioning signal from the transmitting antenna. The receiving antenna is movable, and its position and orientation relative to the metasurface are unknown and need to be estimated through signal processing. The signal strength and phase information received by the receiving antenna are sent to the USRP for processing and used for positioning calculations.

[0119] The USRP controls the transmit and receive antennas and performs positioning calculations. The USRP possesses powerful real-time signal processing capabilities. After acquiring signals at the receiver, it can perform phase difference measurements, time of arrival (ToA), and angle of arrival (AoA) for precise positioning. When controlling the transmit antennas to transmit signals, the USRP considers the metasurface's phase configuration information, which is provided by the metasurface's codebook calculation module and used to optimize the signal propagation path.

[0120] The specific positioning process is as follows: Figure 8As shown, the USRP controls the positioning transmit antenna to transmit a modulated RF signal. This signal passes through the metasurface structure, where its phase distribution is configured by the codebook calculation module to optimize the signal transmission path. The positioning receive antenna receives this signal, and the USRP collects and analyzes the signal's time delay and phase difference. The USRP uses the metasurface phase configuration information, the position and orientation of the transmit antenna, and the characteristics of the received signal to estimate the spatial position of the positioning receive antenna. The USRP outputs the estimated position of the positioning receive antenna and sends this position information to the codebook calculation module via the signal feedback module.

[0121] The communication transceiver module simulates the base station at the transmitting end and the mobile user at the receiving end to build a communication link for signal transmission and reception processing. Figure 9 shown.

[0122] The transmitter includes:

[0123] The transmitting antenna is used to radiate the radio frequency signal generated by the transmitter into space. It includes omnidirectional antennas and directional antennas, which are used to cover a wide area and a specific area respectively.

[0124] RF switch, used to switch between different transmission modes. The switch is driven by a control signal and can respond quickly.

[0125] A power amplifier is used to boost the signal power to the required transmission power level to ensure that the signal can effectively cover the communication range. The power amplifier usually has linear characteristics to prevent signal distortion;

[0126] A mixer upconverts the baseband or IF signal to the desired radio frequency (RF) band. The mixer receives a local oscillator signal from a phase-locked loop (PLL) and mixes it with the input signal to produce an RF output.

[0127] Phase-locked loop, used to generate a stable local oscillator signal (LO) for use by the mixer;

[0128] A low-pass filter is used to remove high-order harmonics and other unwanted frequency components from the mixer output, retaining only the signal within the target frequency range. The filter is designed as a microstrip line structure;

[0129] Digital-to-analog converter, which converts the baseband signal into an analog signal;

[0130] Digital frequency converter, converts baseband signal to intermediate frequency or directly generates RF signal.

[0131] The receiving end includes:

[0132] The receiving antenna is used to capture the radio frequency signal transmitted from the transmitter. It includes omnidirectional antennas and directional antennas, which are used to cover a wide area and a specific area respectively.

[0133] RF switch, selects different receiving modes at the receiving end;

[0134] Low-noise power amplifiers amplify weak RF signals received in their early stages while minimizing the amount of noise introduced;

[0135] The mixer mixes the received RF signal with the local oscillator signal from the phase-locked loop and down-converts it to an intermediate frequency or baseband for subsequent signal processing. The mixer is designed as a double-balanced structure to reduce distortion and noise;

[0136] Phase-locked loop, used at the receiving end to generate a local oscillator signal, ensuring that the received RF signal can be accurately down-converted to an intermediate frequency or baseband;

[0137] The low-pass filter is used in the signal path after mixing to filter out high-frequency noise and clutter, retaining useful signal components and ensuring signal purity and stability;

[0138] Analog-to-digital converter, which digitizes the analog intermediate frequency or baseband signal for use in the digital signal processing unit;

[0139] Digital frequency converter, used to down-convert the digitized intermediate frequency signal to baseband.

[0140] The workflow of the communication transceiver module is as follows:

[0141] The transmitter generates a baseband signal and converts it to an analog signal via a digital-to-analog converter. A digital frequency converter converts the baseband signal to an intermediate frequency (IF) or radio frequency (RF), and a mixer further upconverts the signal to the desired communication frequency band. After filtering the RF signal through a low-pass filter, it is amplified by a power amplifier and controlled by an RF switch. The signal is ultimately radiated into space through the transmitting antenna, forming the transmitter's output signal.

[0142] After the receiving antenna receives the RF signal, it undergoes initial amplification via a low-noise power amplifier (LNA). The RF switch then selects the appropriate receive path. A mixer downconverts the received signal to an intermediate frequency (IF) or baseband. After a low-pass filter removes unnecessary frequency components, the signal enters an analog-to-digital converter (ADC) for digitization. A digital converter further downconverts the digitized signal to baseband for demodulation and data extraction by the digital signal processing module.

Claims

1. A reconfigurable intelligent metasurface beam tracking device, characterized in that: Specifically include: Reconfigurable intelligent metasurface module, communication transceiver module, signal feedback module, codebook calculation module, voltage regulation module and positioning perception module; The reconfigurable intelligent metasurface module includes a plurality of metasurface units arranged in a periodic manner to form a two-dimensional array. The metasurface units are integrated with tunable elements, namely varactor diodes, and phase reconfiguration is achieved by changing the reverse bias voltage of the varactor diodes. The communication transceiver module includes a transmitting end and a receiving end. The transmitting end excites the transmission signal to the reconfigurable intelligent metasurface module, and the receiving end receives the reflected signal from the reconfigurable intelligent metasurface module and sends the received signal quality information to the signal feedback module. The signal feedback module transmits the receiving end position information and the received signal quality information to the codebook calculation module; The codebook calculation module calculates the phase control codebook of the reconfigurable intelligent metasurface module according to the data fed back by the signal feedback module, converts it into a corresponding control voltage value, and transmits the digital signal corresponding to the voltage value to the voltage control module; Specifically, the codebook calculation module implements capacitance control by providing a reverse bias voltage to the varactor diode. The equivalent load impedance of the reflective unit changes with the change in capacitance. An adaptive iterative algorithm is executed based on feedback information to calculate the optimal codebook. These codebooks are converted into corresponding control voltage information and sent to the voltage control module to control the electromagnetic response of the reconfigurable metasurface unit. The voltage control module is used to output multiple independent voltage signals, each of which is output to a corresponding metasurface unit; it includes a data register, multiple digital-to-analog conversion circuits, and several output buffers, wherein: the data register is used to temporarily store voltage information to be applied to the metasurface unit; the digital-to-analog conversion circuit receives digital voltage information from the data register and converts it into an analog voltage signal, each data register corresponds to an independent digital-to-analog conversion channel, ensuring that multiple voltage values ​​are processed in parallel; the buffer provides the necessary current driving capability and stabilizes the output voltage to ensure that the voltage applied to the resonant unit is accurate; The positioning sensing module is used to sense the position information of the receiving end and send the position of the receiving end to the signal feedback module; To reduce the complexity of codebook search, in a two-dimensional array of reconfigurable smart metasurface modules, reflective units in the same row share a horizontal phase gradient, and reflective units in the same column share a vertical phase gradient. Phase iteration logic is performed by updating the phase gradients of each row and column. The phase iteration logic includes: (1) First, the phase gradient of the metasurface array is randomly initialized to evaluate the radiation pattern and obtain the received signal quality at the receiving end; (2) Randomly select a row or column of the metasurface array, change the phase gradient, continue to evaluate the radiation pattern, and obtain the received signal quality at the receiving end; (3) Determine whether the quality of the received signal at the receiving end is greater than the quality of the received signal in the previous iteration. If so, fix the phase gradient change of the row or column; otherwise, discard the phase gradient change of the row or column and repeat (2).

2. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The reconfigurable metasurface unit includes a substrate material, a resonant structure, a reconfigurable element, a feeder circuit and a packaging layer; wherein: the substrate material is the supporting structure of the metasurface unit; the resonant structure is used to interact with electromagnetic waves to achieve specified electromagnetic characteristics; the reconfigurable element is used to dynamically adjust the electromagnetic response of the metasurface; the feeder circuit is used to drive the reconfigurable element to achieve dynamic adjustment; and the packaging layer is used to protect the metasurface unit from environmental influences.

3. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The codebook calculation module is implemented by a high-performance programmable device and is responsible for executing the adaptive iterative algorithm.

4. The reconfigurable intelligent metasurface beam tracking device according to claim 1, wherein: The reflection coefficient is determined by the equivalent load impedance of the reflection unit and the characteristic impedance of the air in the system: in, is the equivalent load impedance of the reflection unit, is the characteristic impedance of air; Therefore, the phase adjustment of the reflector unit is: By adjusting the external bias voltage of the varactor diode in the reflection unit, the coefficient of each reflection unit can be dynamically controlled.

5. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The codebook calculation module performs a codebook adaptive iterative algorithm based on the receiving end position to calculate the phase codebook, specifically: Where, represents the number of electromagnetic waves in space, and Represent the size of the hypersurface unit in the x-axis and y-axis respectively, Indicates that the feed source is The distance of the metasurface unit, is the azimuth angle of the receiving end relative to the metasurface unit, is the pitch angle of the receiving end relative to the metasurface unit.

6. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The codebook calculation module performs a codebook adaptive iterative algorithm to search the codebook based on the received signal quality at the receiving end. The reflection phase of the metasurface unit is divided into three parts: It only depends on the geometric relationship between the feed source and the metasurface unit and is a fixed value; Reflects the phase gradient in the horizontal direction; Reflects the phase gradient in the vertical direction; The compensation phase of the metasurface unit is represented as the superposition of the horizontal phase gradient and the vertical phase gradient.

7. The reconfigurable intelligent metasurface beam tracking device according to claim 1, wherein: The positioning perception module includes a positioning transmitting antenna, a positioning receiving antenna and a signal processing device, wherein the positioning transmitting antenna and the receiving antenna are respectively connected to the signal processing device, the signal processing device controls the positioning transmitting antenna to transmit signals, and estimates the position of the positioning transmitting antenna according to the received signal of the positioning receiving antenna based on the phase configuration information of the metasurface unit and the position and direction of the positioning receiving antenna relative to the metasurface unit.

8. The reconfigurable intelligent metasurface beam tracking device according to claim 1, wherein the working process is as follows: Step 1: The transmitter in the communication transceiver module transmits a signal. When the receiver moves at any time, the positioning transmitting antenna in the positioning sensing module follows the receiver and transmits a positioning signal in real time. Step 2: The positioning receiving antenna in the positioning sensing module receives the positioning signal from the positioning transmitting antenna, obtains the real-time position information of the receiving end after signal processing, and sends the position signal to the signal feedback module; Step 3: The signal feedback module further feeds back the position information of the receiving end to the codebook calculation module; Step 4: The codebook calculation module calculates the reflection coefficient of the metasurface array based on the position information of the receiving end, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface module, and transmits the digital control signal corresponding to the voltage value to the voltage control module; Step 5: The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, changing the phase gradient of the metasurface array, thereby reflecting the signal from the transmitting end to the position of the receiving end, realizing real-time dynamic beam tracking, and the reflected signal moves together with the receiving end.

9. The reconfigurable intelligent metasurface beam tracking device according to claim 1, wherein another working process is: Step 1: The codebook calculation module initializes the reflection coefficient of the metasurface array, converts the reflection coefficient into the reverse bias voltage of the varactor diode in the reconfigurable intelligent metasurface, and transmits the digital control signal corresponding to the voltage value to the voltage control module; Step 2: The voltage control module converts the digital control signal into an analog voltage signal and outputs it to the reconfigurable intelligent metasurface module, thereby changing the phase gradient of the metasurface array; Step 3: The transmitter in the communication transceiver module transmits a signal, and the reconfigurable metasurface module reflects the incident signal from the transmitter to the receiver. When the receiver moves arbitrarily, the quality information of the received signal is fed back to the signal feedback module. Step 4: The signal feedback module further feeds back the received signal quality information of the receiving end to the codebook calculation module; Step 5: The codebook calculation module determines whether the received signal quality reaches the threshold. If so, the receiving end and the transmitting end communicate normally, realizing real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the received signal quality until the received signal quality at the receiving end reaches the threshold.

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