Reconfigurable intelligent metasurface beam tracking device

Abstract

The invention discloses a reconfigurable intelligent metasurface beam tracking device, and belongs to the technical field of wireless communication. Specifically, the reconfigurable intelligent metasurface module integrates a large number of metasurface units, a tunable element is embedded to achieve reconfiguration of electromagnetic characteristics, a receiving end of the communication receiving and transmitting module receives reflected signals of the metasurfaces and feeds back the quality of the received signals in the moving process, and the positioning sensing module senses the position of the receiving end in real time. And the codebook calculation module calculates a phase regulation codebook based on the signal quality and the position feedback information, converts the phase regulation codebook into a control voltage value, transmits a corresponding digital control signal to the voltage regulation module, and outputs multiple paths of analog voltages, so that the reflection coefficient of the metasurface array is regulated and controlled, and real-time dynamic wave beam tracking is realized. According to the invention, the coverage range, the transmission rate and the service quality of the communication network are obviously improved.

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 that has attracted widespread attention in the field of wireless communications, especially in the sixth generation (6G) wireless communication networks. RIS integrates a large number of reflection units to achieve programmable electromagnetic wave control capabilities, providing a more flexible and efficient solution for wireless communications.

[0003] However, in RIS-assisted mobile communication scenarios, the accuracy of beam tracking becomes an important challenge as users move and the environment changes. In the existing technology, although RIS can adjust the direction of the beam to a certain extent, the complexity and calculation amount of beam control are greatly increased due to the large number of RIS reflection units, resulting in existing systems facing greater technical obstacles when dealing with mobile scenarios.

[0004] In addition, beam tracking requires not only a highly sensitive control capability, but also the ability to capture changes in the user's position in a timely manner in order to quickly adjust the beam. However, existing technologies are insufficient in positioning and tracking capabilities, lacking real-time perception and rapid response mechanisms, making it difficult for existing systems to achieve efficient beam tracking in scenarios where users are moving.

[0005] Therefore, there is still a large technical gap in the existing system, and new solutions are urgently needed to address the complexity of beam control 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 constructing a signal feedback link, based on real-time perception and positioning, the metasurface control codebook is adaptively and quickly iterated, so that the system can realize 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 comprises: 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, which are arranged in a periodic manner to form a two-dimensional array. The metasurface units realize reconfigurable electromagnetic characteristics by integrating tunable elements. The tunable elements are varactor diodes, and phase reconfiguration is realized 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] Further, the codebook calculation module executes a codebook adaptive iterative algorithm through 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 according to the position information:

[0016]

[0017] In the formula, k represents the number of electromagnetic waves in space, d x and d y denote the size of the hypersurface unit on the x-axis and y-axis, respectively, d i,j represents the distance from the feed source to the hypersurface 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;

[0018] 2) For the 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, the reflective units in the same row share a horizontal phase gradient, and the reflective units in the same column share a vertical phase gradient. The phase iteration logic is performed by updating the phase gradients of each row and column.

[0024] Furthermore, the positioning sensing 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 being the quality of a received signal at a 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 receiving end moves arbitrarily, the positioning transmitting antenna in the positioning sensing module follows the movement of the receiving end 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 location 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 according to 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 beam dynamic tracking, and the reflected signal moves with the receiving end.

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

[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 incident signal of the transmitter is reflected to the receiving end through the reconfigurable metasurface module. When the receiving end 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 quality of the received signal reaches the threshold. If so, the receiving end communicates normally with the transmitting end to achieve real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the quality of the received signal until the quality of the received signal 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 a column of the metasurface array and change the phase gradient to continue evaluating 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, which has a designed metasurface unit structure and realizes phase reconfiguration based on a varactor diode. It has a simple structure and is easy to integrate and implement.

[0043] 2. The present invention provides a reconfigurable intelligent metasurface beam tracking device, and the designed metasurface-assisted positioning solution has high scalability and is easy to integrate with the existing metasurface system;

[0044] 3. The invention discloses a reconfigurable intelligent metasurface beam tracking device, and 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 It is a schematic diagram of calculating the reflection coefficient of the reconfigurable intelligent metasurface of the present invention;

[0048] Figure 3 It is a 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 It is a schematic diagram of the working logic of the positioning perception module adopted in the embodiment of the present invention;

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

[0055] The present invention is further described below in conjunction with 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 realize reconfigurable electromagnetic characteristics by integrating tunable elements. The tunable elements are varactor diodes, and phase reconfiguration is realized 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, according to 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 receiving end position to the signal feedback module;

[0063] Further, the codebook calculation module executes a codebook adaptive iterative algorithm through 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, the codebook adaptive iterative algorithm directly calculates the reflection phase of each unit according to the position information:

[0065]

[0066] In the formula, k represents the number of electromagnetic waves in space, d x and d y denote the size of the hypersurface unit on the x-axis and y-axis, respectively, d i,j represents the distance from the feed source to the hypersurface 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 of the receiving end, the codebook adaptive iterative algorithm searches the codebook based on the received signal quality of 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, the reflective units in the same row share a horizontal phase gradient, and the reflective units in the same column share a vertical phase gradient. The phase iteration logic is performed by updating the phase gradients of each row and column.

[0073] Furthermore, the positioning sensing 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] For feedback information being 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 receiving end moves arbitrarily, the positioning transmitting antenna in the positioning sensing module follows the movement of the receiving end 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 location 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 according to 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 beam dynamic tracking.

[0080] For feedback information being 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 incident signal of the transmitter is reflected to the receiving end through the reconfigurable metasurface module. When the receiving end moves arbitrarily, the signal quality information is received and sent 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 quality of the received signal reaches the threshold. If so, the receiving end communicates normally with the transmitting end to achieve real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the quality of the received signal until the quality of the received signal 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 quality of the received signal at the receiving end is obtained;

[0088] (5) Randomly select a row or a column of the metasurface array and change the phase gradient to continue evaluating 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, which will produce a small amount of information loss and cause a slight increase in the beam sidelobes, but will not affect its application in actual systems.

[0091] At this time, for an M×N unit supersurface 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 the reconfigurable metasurface unit is: by arranging resonant units with specific shapes and sizes on the substrate material, these units resonate with the incident electromagnetic waves, thereby controlling the amplitude and phase characteristics of the waves. By introducing adjustable devices, the electromagnetic response of the resonant unit is dynamically changed, realizing real-time control of the electromagnetic waves.

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

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

[0097] The top metal patch is an I-shaped copper metal patch. Its induced electric field appears in the gap between the two microstrip patches, which is equivalent to a sheet capacitor. The high-frequency current flows back and forth between the capacitor gap, which is equivalent to the series connection of effective inductance impedance and resistance. The single resonant electromagnetic response reflected is significant. A variable capacitance diode model MAVR-000020-1411P is loaded in the middle. This GaAs tuning diode can provide broadband performance from 10MHz to 70GHz, which is used to change the surface current distribution at different positions of the metal patch, thereby realizing 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 , which is a top view of the super surface unit of this example, and the structural dimensions of the super surface 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 a plurality of output buffers, such as Figure 7 As shown, wherein: 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, the data register can be written with data through a microcontroller (MCU) or a field programmable gate array (FPGA). The microcontroller receives voltage instructions from a host computer or control software and writes these instructions into the data register in digital form. The digital-to-analog conversion circuit can be a T-type conversion circuit composed 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 according to feedback information, calculate the optimal codebook, and convert these codebooks into corresponding control voltages, which are finally sent to the voltage control 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 (Central Processing Units, CPUs), which are responsible for executing the adaptive iterative algorithm.

[0107] The principle of codebook calculation is: by providing bias voltage to the varactor diode to achieve the control of the phase of the electromagnetic wave, 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, which 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 of the system:

[0108]

[0109] Among them, Z1 is the unit equivalent load impedance, Z0 is the characteristic impedance of air, so the phase adjustment of the reflection 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, and the position information includes the direction angle and distance of the receiving end relative to the metasurface.

[0115] Specifically, the wireless transmission link uses a WiFi module to achieve wireless transmission. The WiFi module can provide a stable communication link, support high-bandwidth data transmission, and is easy to integrate. The WiFi module establishes a communication connection between the receiving end and the codebook calculation module, and transmits the data packet to the codebook calculation module through the UDP or TCP / IP protocol. The data packet contains important feedback information such as the 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 performed using the phase configuration of the metasurface structure and the 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 the receiving antenna are respectively connected to the USRP signal processing device, and the USRP controls the positioning transmitting antenna to transmit signals and estimates the position of the positioning transmitting antenna based on the received signals.

[0117] The positioning transmitting antenna is connected to the USRP signal processing device to transmit the positioning signal. The positioning transmitting antenna includes omnidirectional antenna and directional antenna, and the specific selection depends on the application scenario. The transmission signal of the transmitting antenna includes narrowband and broadband signals to support positioning requirements of different resolutions. The USRP controls the signal parameters of the transmitting antenna, including frequency, power and modulation mode.

[0118] The positioning receiving antenna is connected to the USRP signal processing device to receive the positioning signal from the transmitting antenna. The receiving antenna can move, and its position and direction 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 calculation.

[0119] USRP is responsible for controlling the transmitting antenna and receiving antenna and performing positioning calculations. USRP has powerful real-time signal processing capabilities. After collecting signals at the receiving end, it can perform phase difference measurement, time of arrival (ToA) measurement, and angle of arrival (AoA) measurement for precise positioning. When controlling the transmitting antenna to transmit signals, USRP takes into account the phase configuration information of the metasurface. This configuration information is provided by the metasurface codebook calculation module to optimize the signal propagation path.

[0120] The specific positioning process is as follows: Figure 8As shown in the figure, USRP controls the positioning transmitting antenna to transmit the modulated RF signal. The signal passes through the metasurface structure, and its phase distribution has been configured by the codebook calculation module to optimize the signal transmission path. The positioning receiving antenna receives the signal, and USRP collects and analyzes the signal delay and phase difference information. USRP uses the metasurface phase configuration information, the position and direction of the transmitting antenna, and the characteristics of the received signal to estimate the spatial position of the positioning receiving antenna. USRP outputs the estimated position of the positioning receiving antenna and sends the position information to the codebook calculation module through 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 transceiver processing. Fig. 9 shown.

[0122] The transmitter includes:

[0123] Transmitting antennas are used to radiate the radio frequency signals generated by the transmitter into space, including omnidirectional antennas and directional antennas, which are used to cover a wide area and focus on covering 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] Power amplifier, used to increase 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 up-converts the baseband or IF signal to the target radio frequency (RF) band. The mixer accepts a local oscillator signal from a phase-locked loop (PLL) and mixes it with the input signal to produce an RF output.

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

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

[0129] A digital-to-analog converter 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] Receiving antennas are used to capture radio frequency signals from the transmitter, including omnidirectional antennas and directional antennas, which are used to cover a wide area and focus on a specific area respectively;

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

[0134] Low-noise power amplifiers that amplify weak received RF signals 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] Low-pass filter, in the signal path after mixing, is used to filter out high-frequency noise and clutter, retain useful signal components, and ensure signal purity and stability;

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

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

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

[0141] The transmitter generates a baseband signal and converts it into an analog signal through a digital-to-analog converter. The digital frequency converter converts the baseband signal to an intermediate frequency or radio frequency, and the mixer further up-converts the signal to the required communication frequency band. The RF signal filtered by the low-pass filter is amplified by the power amplifier, and the path is controlled by the RF switch, and finally radiated into space through the transmitting antenna to form the signal output of the transmitter.

[0142] After the receiving antenna receives the RF signal, the signal is initially amplified by a low-noise power amplifier, and then the appropriate receiving path is selected by the RF switch. The mixer down-converts the received signal to an intermediate frequency or baseband, and after the low-pass filter removes unnecessary frequency components, the signal enters the analog-to-digital converter for digital processing. The digital converter further down-converts 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 comprises a plurality of metasurface units arranged in a periodic manner to form a two-dimensional array, and the metasurface units realize reconfigurable electromagnetic properties by integrating tunable elements; 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; The voltage control module is used to output multiple independent voltage signals, and each voltage signal is output to a corresponding metasurface unit; 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.

2. A reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The tunable element is a varactor diode, and phase reconfiguration is achieved by changing the reverse bias voltage of the varactor diode.

3. A reconfigurable intelligent metasurface beam tracking device as claimed in 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.

4. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The voltage control module includes a data register, a multi-channel digital-to-analog conversion circuit and a plurality of output buffers, wherein: 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 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.

5. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The codebook calculation module is used to execute an adaptive iterative algorithm according to feedback information, calculate the optimal codebook, convert these codebooks into corresponding control voltage information, and send it to the voltage regulation module to control the electromagnetic response of the reconfigurable metasurface unit.

6. A reconfigurable intelligent metasurface beam tracking device as claimed in claim 1 or 5, characterized in that: The codebook calculation module is implemented by a high-performance programmable device and is responsible for executing an adaptive iterative algorithm.

7. A reconfigurable intelligent metasurface beam tracking device as claimed in claim 1, 5 or 6, characterized in that: The principle of the codebook calculation is: capacitance regulation is achieved by providing a reverse bias voltage to a varactor diode, and the equivalent load impedance of the reflection unit changes with the change of the capacitance.

8. The reconfigurable intelligent metasurface beam tracking device according to claim 7, characterized in that: The reflection coefficient is determined by the equivalent load impedance of the reflection unit and the characteristic impedance of the system air: Among them, Z1 is the equivalent load impedance of the reflection unit, and Z0 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.

9. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The codebook calculation module performs a codebook adaptive iterative algorithm at the receiving end position to calculate a phase codebook, specifically: In the formula, k represents the number of electromagnetic waves in space, d x and d y denote the size of the hypersurface unit on the x-axis and y-axis, d i,j represents the distance from the feed source to the hypersurface unit with coordinates (i, j), is the azimuth angle of the receiving end relative to the metasurface unit, and θ is the elevation angle of the receiving end relative to the metasurface unit.

10. 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 according to the quality of the received signal at the receiving end. The reflection phase of the metasurface unit is divided into three parts: 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; 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.

11. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: To reduce the complexity of codebook search, in the two-dimensional array of reconfigurable smart metasurface modules, the reflective units in the same row share a horizontal phase gradient, and the reflective units in the same column share a vertical phase gradient. The phase iteration logic is executed by updating the phase gradients of each row and column.

12. The reconfigurable intelligent metasurface beam tracking device according to claim 11, characterized in that: 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 and change the phase gradient to continue evaluating the radiation pattern. Obtain the quality of the signal received by 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).

13. The reconfigurable intelligent metasurface beam tracking device according to claim 1, characterized in that: The positioning sensing 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.

14. 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 receiving end moves arbitrarily, the positioning transmitting antenna in the positioning sensing module follows the movement of the receiving end 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 location information of the receiving end to the codebook calculation module; Step 4: The codebook calculation module calculates the reflection coefficient of the metasurface array according to 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 beam dynamic tracking, and the reflected signal moves with the receiving end.

15. 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 incident signal of the transmitter is reflected to the receiving end through the reconfigurable metasurface module. When the receiving end 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 quality of the received signal reaches the threshold. If so, the receiving end communicates normally with the transmitting end to achieve real-time dynamic tracking of the beam; otherwise, the phase iteration logic is executed according to the quality of the received signal until the quality of the received signal at the receiving end reaches the threshold.

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