Communication perception integration method and system based on space-time coding metasurface

Abstract

The invention discloses a communication perception integration method and system based on a space-time coding metasurface. The method comprises the steps that the coding metasurface is divided into a space-time coding area and a space coding area; an incoming wave irradiates the metasurface, and a space-time coding area on the coding metasurface converts a part of the incoming wave into a multi-order harmonic wave through a designed space-time coding matrix; the spatial distribution of harmonic waves is received and analyzed, and the direction of arrival is sensed; according to the perceived direction of arrival and an expected target direction, a space coding sequence is created, the space coding sequence controls a space coding area to deflect a fundamental frequency carrier to the expected target direction, and a communication link is established; by designing the coding scheme of the space-time coding metasurface, reliable sensing and wireless communication links can be established at the same time, multi-order harmonics distributed in the space are generated for sensing, and meanwhile, the transmission direction of fundamental frequency carriers is controlled for wireless communication, so that the communication quality can be greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of novel artificial electromagnetic materials and communication technology, and specifically relates to a communication perception integration method and system based on space-time coding metasurface. Background Art

[0002] The coded metasurface is an artificial planar structure that can dynamically control electromagnetic waves to achieve an intelligent wireless environment. The emerging integrated communication and perception is also an important candidate technology for the sixth-generation wireless communication system. It uses shared spectrum, hardware platform and signal processing functions to seamlessly integrate sensing and wireless communication, reducing hardware costs and power consumption. The synergy between the coded metasurface and the integrated communication and perception system is expected to promote the development of wireless network technology.

[0003] When the direct path between the sensing target and the base station is blocked, the coded metasurface can establish a non-line-of-sight link and reflect the signal to achieve the sensing function. However, in this case, the coded metasurface is usually unable to collect environmental information on its own and usually needs to rely on the base station to transmit external control signals through a dedicated control link to configure its phase pattern. To address this limitation, sensors or detectors can be integrated into the coded metasurface, so that the phase pattern can be dynamically configured, realizing sensing and communication at the same time and eliminating the need for a dedicated control link from the base station. However, the integration of sensors or detectors requires additional peripheral circuits, resulting in increased hardware costs. Summary of the invention

[0004] Purpose of the invention: In order to solve the problems of complex hardware structure and high cost in the existing communication perception integration system, the present invention proposes a communication perception integration method and system based on space-time coding metasurface.

[0005] Technical solution: A communication and perception integration method based on space-time coding metasurface, comprising the following steps:

[0006] The coding metasurface is divided into a spatiotemporal coding region and a spatial coding region;

[0007] When the incoming wave hits the metasurface, the space-time coding area on the coding metasurface converts part of the incoming wave into multi-order harmonics through the designed space-time coding matrix.

[0008] By analyzing the spatial distribution of harmonics, the direction of the incoming waves can be perceived;

[0009] A spatial coding sequence is created according to the sensed incoming wave direction and the desired target direction. The spatial coding sequence controls the spatial coding region to deflect the baseband carrier to the desired target direction, thereby establishing a communication link.

[0010] Furthermore, the above-mentioned sensing of the incoming wave direction by analyzing the spatial distribution of harmonics includes:

[0011] The harmonic frequency f c +vf0, v = ±1, ±2...±M along the normal direction, the amplitude is arranged into a vector s (θ i );

[0012] The normalized vector is:

[0013] x(θ i )=s(θ i ) / max[s(θ i )]

[0014] Analyze the spatial-spectral characteristics of the harmonics generated in the spatiotemporal coding region and obtain the normalized harmonic amplitude vector x(θ i ) and the incoming wave direction θ i The relationship between them can realize the perception of the incoming wave direction.

[0015] Furthermore, the spatial coding sequence is created according to the perceived incoming wave direction and the desired target direction, and the specific operations include:

[0016] Assume that the incoming wave direction is θ i , the desired target direction is To deflect the baseband carrier to the desired target direction, the phase difference between the phase responses of adjacent metasurface units is expressed as:

[0017]

[0018] Among them, k c =2πf c / c represents the wavelength of the fundamental frequency carrier in free space, c represents the speed of light, and d represents the spatial period of the metasurface unit;

[0019] Therefore, the phase response of the nth column of metasurface units can be expressed as:

[0020]

[0021] Based on the phase response of each metasurface unit, a spatially encoded sequence is created.

[0022] Furthermore, when the incoming wave direction changes, the perception of the incoming wave direction is updated by analyzing the spatial distribution of harmonics in real time, thereby adjusting the spatial coding sequence of the spatial coding area accordingly.

[0023] Furthermore, the coding metasurface is a reflective coding metasurface or a transmissive coding metasurface.

[0024] The present invention discloses a communication perception integrated system based on space-time coding metasurface, comprising a coding metasurface, a control circuit module and an analysis and calculation module;

[0025] The coding metasurface is divided into a space-time coding region and a spatial coding region; the space-time coding region adopts space-time coding modulation and periodically switches its working state according to the space-time coding matrix; the spatial coding region deflects the baseband carrier to the target direction to establish a communication link;

[0026] The control circuit module is used to provide a control signal of the coding metasurface, control the working state of the coding metasurface unit, so that the spatiotemporal coding area on the coding metasurface periodically switches its working state, converts part of the incoming wave into multi-order harmonics, and controls the spatial coding area according to the spatial coding sequence;

[0027] The analysis and calculation module is used to analyze the spatial distribution of the received harmonics, realize the perception of the incoming wave direction, and create a spatial coding sequence according to the perceived incoming wave direction and target direction.

[0028] Furthermore, in the analysis and calculation module, the spatial distribution of harmonics is analyzed to realize the perception of the incoming wave direction, and the specific operations include:

[0029] The harmonic frequency f c +vf0, v = ±1, ±2...±M along the normal direction, the amplitude is arranged into a vector s (θ i );

[0030] The normalized vector is:

[0031] x(θ i )=s(θ i ) / max[s(θ i )]

[0032] Analyze the spatial-spectral characteristics of the harmonics generated in the spatiotemporal coding region and obtain the normalized harmonic amplitude vector x(θ i ) and the incoming wave direction θ i The relationship between them can realize the perception of the incoming wave direction.

[0033] Furthermore, in the analysis and calculation module, the spatial coding sequence is created according to the perceived incoming wave direction and the desired target direction. The specific operations include:

[0034] Assume that the incoming wave direction is θ i , the desired target direction is To deflect the baseband carrier to the desired target direction, the phase difference between the phase responses of adjacent metasurface units is expressed as:

[0035]

[0036] Among them, k c =2πfc / c represents the wavelength of the fundamental frequency carrier in free space, c represents the speed of light, and d represents the spatial period of the metasurface unit;

[0037] Therefore, the phase response of the nth column of metasurface units can be expressed as:

[0038]

[0039] Based on the phase response of each metasurface unit, a spatially encoded sequence is created.

[0040] Furthermore, in the analysis and calculation module, when the incoming wave direction changes, the spatial distribution of harmonics is analyzed in real time to update the perception of the incoming wave direction, thereby adjusting the spatial coding sequence of the spatial coding area accordingly.

[0041] Furthermore, the coding metasurface is a reflective coding metasurface or a transmissive coding metasurface.

[0042] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0043] (1) The present invention can simultaneously establish reliable perception and wireless communication links by designing a coding scheme for the space-time coding metasurface, generate multi-order harmonics distributed in space for perception, and control the propagation direction of the baseband carrier for wireless communication, thereby greatly improving the communication quality; that is, the present invention can obtain the direction information of the incoming wave by analyzing the amplitude information of the harmonics, thereby adjusting the coding arrangement of the space-time coding metasurface, and deflecting the baseband beam to the target direction to ensure the stability of the communication system;

[0044] (2) The present invention uses harmonics for sensing, without the need to integrate additional sensors or dedicated control links from base stations. It can simultaneously perform sensing and communication functions on a shared hardware platform. The two functions can work simultaneously without interfering with each other. Even if the direction of the incoming wave changes in real time, the reliability of the entire communication system can still be guaranteed.

[0045] (3) Compared with the traditional communication and perception integrated system relying on phased array antennas, the present invention has more advantages in reducing hardware cost and power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a communication-sensing integration method and system based on a spatiotemporal coding metasurface;

[0047] Figure 2 An example of a space-time coding matrix used for region 1 of a space-time coding metasurface, an example of a space coding sequence used for region 2, and a schematic diagram of the corresponding fundamental carrier and harmonic far-field patterns;

[0048] Figure 3A schematic diagram of an implementation scheme for a communication-perception integration method based on a spatiotemporal coding metasurface;

[0049] Figure 4 Schematic diagram of the workflow of the communication-perception integration method based on spatiotemporal coding metasurface. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following will further illustrate the communication perception integration method and system based on space-time coding metasurface proposed by the present invention in combination with the accompanying drawings and embodiments.

[0051] Embodiment 1:

[0052] like Figure 4 As shown, this embodiment proposes a communication and perception integration method based on space-time coding metasurface, which uses certain specific harmonics for wireless sensing and can regulate the propagation of baseband carriers, and simultaneously establishes reliable perception and wireless communication links by controlling the space-time coding matrix. It mainly includes the following steps:

[0053] Step 1: Divide the space-time coding hypersurface into two regions, including region 1 and region 2, as shown in Figure 3 ; Region 1 adopts space-time coding modulation, and its working state is periodically switched according to the space-time coding matrix. Region 2 adopts space coding, which can be switched on demand using the control circuit module; the area and relative position of the two regions can be flexibly adjusted; the space-time coding metasurface in this step can be reflective or transmissive, and each metasurface unit presents a corresponding electromagnetic response according to the control signal. Figure 2 An example of a space-time coding matrix used in region 1, an example of a space coding sequence used in region 2, and a schematic diagram of the corresponding fundamental frequency carrier and harmonic wave far-field patterns are shown.

[0054] Step 2: When the incoming wave is irradiated onto the space-time coding metasurface, region 1 converts part of the incoming wave into multi-order harmonics. Different incoming wave directions make the harmonics present different spatial distributions. A group of harmonics is selected, and the spatial distribution of the harmonics can be analyzed to realize the perception of the incoming wave direction. For example, antenna 1 transmits a modulated signal and irradiates it onto the space-time coding metasurface. By analyzing the spatial distribution of the harmonics received by antenna 2 at a fixed angle, the incoming wave direction of antenna 1 can be estimated.

[0055] Step 3: Based on the estimated incoming wave direction and target direction, the required spatial coding sequence of area 2 is calculated so that the baseband carrier is deflected to the target direction, thereby establishing a communication link;

[0056] Step 4: When the incoming wave direction changes, the spatial distribution of the harmonics is analyzed in real time, the incoming wave direction information is updated with low latency, the spatial coding sequence of area 2 is adjusted accordingly, and the information is fed back to the control circuit module to ensure the stability of the communication link between antenna 1 and antenna 3.

[0057] In this embodiment, the perception of the incoming wave direction and the establishment of the communication link work simultaneously and do not interfere with each other. Therefore, even if the incoming wave direction changes, the incoming wave direction information can still be updated by real-time analysis of the spatial distribution of harmonics to ensure that the baseband carrier is always deflected to the target direction.

[0058] Now take a 2-bit reflective coded digital metasurface as an example. The metasurface is composed of 16×16 metasurface units, each of which integrates two PIN diodes. Each metasurface unit can switch between four states: "OFF-OFF", "ON-OFF", "OFF-ON" and "ON-ON", achieving a 90° phase difference, and the corresponding digital states can be represented by "0", "1", "2" and "3". The metasurface is divided into two regions. Region 1 adopts space-time coding modulation and periodically switches its working state according to the space-time coding matrix, while region 2 adopts spatial coding and can be switched on demand. The area and relative position of the two regions can be adjusted flexibly.

[0059] The space-time coding matrix required by region 1 is designed to adjust the spatial distribution of harmonics and suppress the fundamental frequency component of the reflected wave. When the incoming wave is irradiated onto the metasurface, region 1 converts part of the incoming wave into multi-order harmonics, converting the harmonic frequency f c +vf0, v = ±1, ±2...±M along the normal direction, the amplitude is arranged into a vector s (θ i ), and define the normalized vector as:

[0060] x(θ i )=s(θ i ) / max[s(θ i )]

[0061] Analyze the space-frequency characteristics of the harmonics generated by spatiotemporal modulation and obtain the normalized harmonic amplitude vector x(θ i ) and the incoming wave direction θ i The relationship between them can be used to estimate the direction of the incident wave.

[0062] When the space-time coding metasurface is incident at an angle of θ i Plane wave illumination, designing spatial encoding in region 2, can deflect the baseband carrier to the target direction The desired phase difference between adjacent unit phase responses is expressed as:

[0063]

[0064] Among them, k c =2πf c / c is the wavelength of the fundamental carrier in free space, c is the speed of light, and d is the spatial period of the unit. Therefore, the phase response of the nth column unit can be expressed as

[0065]

[0066] For a 2-bit coded digital metasurface, the phase response of each metasurface unit can have four discrete values ​​(-π / 2, 0, π / 2, π), which can be digitally represented as "0", "1", "2", and "3". Therefore, the phase response of each metasurface unit needs to be quantized into these four discrete values ​​and encoded into corresponding digital codes to create a spatial coding sequence, thereby deflecting the baseband carrier to the target direction to establish a communication link.

[0067] The method mentioned in this embodiment can be applied to microwave, millimeter wave, terahertz and other frequency bands.

[0068] Embodiment 2:

[0069] like Figure 1 As shown, this embodiment proposes a communication perception integrated system based on space-time coding metasurface, which mainly includes a coding metasurface, a control circuit module and an analysis and calculation module.

[0070] The coding metasurface is divided into a space-time coding region and a spatial coding region; the space-time coding region adopts space-time coding modulation and periodically switches its working state according to the space-time coding matrix; the spatial coding region deflects the baseband carrier to the target direction to establish a communication link;

[0071] Among them, the control circuit module is used to provide a control signal of the coding metasurface, control the working state of the coding metasurface unit, so that the spatiotemporal coding area on the coding metasurface periodically switches its working state, converts part of the incoming wave into multi-order harmonics, and controls the spatial coding area according to the spatial coding sequence;

[0072] The analysis and calculation module is used to analyze the spatial distribution of the received harmonics, realize the perception of the incoming wave direction, and create a spatial coding sequence based on the perceived incoming wave direction and the desired target direction.

[0073] The system provided in this embodiment can be used to execute the method provided in this embodiment 1, and has the corresponding functions and beneficial effects of executing the method.

[0074] Any of the above embodiments utilizes harmonics for sensing without the need to integrate additional sensors or dedicated control links from a base station, thereby being able to perform sensing and communication functions simultaneously without causing interference.

Claims

1. A communication perception integration method based on spatiotemporal coding metasurface, characterized by: The following steps are involved: The coding metasurface is divided into a spatiotemporal coding region and a spatial coding region; When the incoming wave hits the metasurface, the space-time coding area on the coding metasurface converts part of the incoming wave into multi-order harmonics through the designed space-time coding matrix. Receive and analyze the spatial distribution of harmonics to sense the direction of incoming waves; A spatial coding sequence is created according to the sensed incoming wave direction and the desired target direction. The spatial coding sequence controls the spatial coding region to deflect the baseband carrier to the desired target direction, thereby establishing a communication link.

2. According to claim 1, a communication perception integration method based on spatiotemporal coding metasurface is characterized by: The analysis of the spatial distribution of harmonics is used to sense the direction of incoming waves. The specific operations include: The harmonic frequency f c +vf0, v = ±1, ±2...±M along the normal direction, the amplitude is arranged into a vector s (θ i ); The normalized vector is: x(θ i )=s(θ i ) / max[s(θ i )] Analyze the spatial-spectral characteristics of the harmonics generated in the spatiotemporal coding region and obtain the normalized harmonic amplitude vector x(θ i ) and the incoming wave direction θ i The relationship between them can realize the perception of the incoming wave direction.

3. According to claim 1, the communication perception integration method based on spatiotemporal coding metasurface is characterized by: The spatial coding sequence is created according to the perceived incoming wave direction and the desired target direction, and the specific operations include: Assume that the incoming wave direction is θ i , the desired target direction is To deflect the baseband carrier to the desired target direction, the phase difference between the phase responses of adjacent metasurface units is expressed as: Among them, k c =2πf c / c represents the wavelength of the fundamental frequency carrier in free space, c represents the speed of light, and d represents the spatial period of the metasurface unit; Therefore, the phase response of the nth column of metasurface units can be expressed as: Based on the phase response of each metasurface unit, a spatially encoded sequence is created.

4. According to claim 1, a communication perception integration method based on spatiotemporal coding metasurface is characterized by: When the incoming wave direction changes, the spatial distribution of harmonics is analyzed in real time to update the perception of the incoming wave direction, thereby adjusting the spatial coding sequence of the spatial coding area accordingly.

5. According to claim 1, the communication and perception integration method based on spatiotemporal coding metasurface is characterized by: The coding metasurface is a reflective coding metasurface or a transmissive coding metasurface.

6. A communication and perception integrated system based on space-time coding metasurface, characterized by: It includes a coding metasurface, a control circuit module and an analysis and calculation module; The coding metasurface is divided into a space-time coding region and a spatial coding region; the space-time coding region adopts space-time coding modulation and periodically switches its working state according to the space-time coding matrix; the spatial coding region deflects the baseband carrier to the desired target direction to establish a communication link; The control circuit module is used to provide a control signal of the coding metasurface, control the working state of the coding metasurface unit, so that the spatiotemporal coding area on the coding metasurface periodically switches its working state, converts part of the incoming wave into multi-order harmonics, and controls the spatial coding area according to the spatial coding sequence; The analysis and calculation module is used to analyze the spatial distribution of the received harmonics, realize the perception of the incoming wave direction, and create a spatial coding sequence according to the perceived incoming wave direction and the desired target direction.

7. The communication and perception integrated system based on space-time coding metasurface according to claim 6 is characterized by: In the analysis and calculation module, the spatial distribution of harmonics is analyzed to realize the perception of the incoming wave direction. The specific operations include: The harmonic frequency f c +vf0, v = ±1, ±2...±M along the normal direction, the amplitude is arranged into a vector s (θ i ); The normalized vector is: x(θ i )=s(θ i ) / max[s(θ i )] Analyze the spatial-spectral characteristics of the harmonics generated in the spatiotemporal coding region and obtain the normalized harmonic amplitude vector x(θ i ) and the incoming wave direction θ i The relationship between them can realize the perception of the incoming wave direction.

8. The communication and perception integrated system based on space-time coding metasurface according to claim 6 is characterized by: In the analysis and calculation module, the spatial coding sequence is created according to the perceived incoming wave direction and the desired target direction. The specific operations include: Assume that the incoming wave direction is θ i , the desired target direction is To deflect the baseband carrier to the desired target direction, the phase difference between the phase responses of adjacent metasurface units is expressed as: Among them, k c =2πf c / c represents the wavelength of the fundamental frequency carrier in free space, c represents the speed of light, and d represents the spatial period of the metasurface unit; Therefore, the phase response of the nth column of metasurface units can be expressed as: Based on the phase response of each metasurface unit, a spatially encoded sequence is created.

9. The communication and perception integrated system based on space-time coding metasurface according to claim 6, characterized in that: In the analysis and calculation module, when the incoming wave direction changes, the spatial distribution of harmonics is analyzed in real time to update the perception of the incoming wave direction, thereby adjusting the spatial coding sequence of the spatial coding area accordingly.

10. The communication and perception integrated system based on space-time coding metasurface according to claim 6, characterized in that: The coding metasurface is a reflective coding metasurface or a transmissive coding metasurface.

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