Terahertz broadband reconfigurable intelligent surface based on vanadium dioxide

Abstract

Methods and apparatus are disclosed for a vanadium dioxide based terahertz broadband reconfigurable smart surface. In one embodiment, an RIS device comprises: a transceiver; and a processor coupled to the transceiver, where the processor is configured to cause the reconfigurable smart surface device to: transmit control signaling indicative of a set of operating frequencies supported by the reconfigurable smart surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receiving a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable smart surface device and using a transmit power based on a reflection efficiency associated with the operating frequency.

Description

Technical Field

[0001] The subject matter disclosed in this article generally relates to wireless communication, and more specifically to applications based on vanadium dioxide (V₂O₃). A device for a broadband reconfigurable smart surface (RIS) in the terahertz (THz) range. Background Technology

[0002] A wireless communication system may include one or more network communication devices, such as base stations, which may also be referred to as eNodeB (eNB), next-generation NodeB (gNB), or other suitable terms. Each network communication device—such as a base station—may support wireless communication for one or more user communication devices—which may also be referred to as user equipment (UE), or other suitable terms. The wireless communication system may support wireless communication with one or more user communication devices by utilizing the resources of the wireless communication system (e.g., time resources (e.g., symbols, time slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers)). In addition, the wireless communication system may support wireless communication across a variety of radio access technologies, including third-generation (3G) radio access technology, fourth-generation (4G) radio access technology, fifth-generation (5G) radio access technology, and other suitable radio access technologies beyond 5G (e.g., sixth-generation (6G)).

[0003] For example, some 6G-enabled wireless communication systems can utilize the THz RF spectrum (e.g., 0.735-0.965 THz) to achieve highly reliable and low-latency exchange of information (e.g., control, data, etc.), and to enable efficient and effective establishment and management of connections (also known as links) between network communication devices, user communication devices, or any combination thereof. In some implementations, connections utilizing the THz RF spectrum may experience channel path and line-of-sight (LOS) problems between network communication devices, user communication devices, or any combination thereof, which can adversely affect the reliability and latency of information exchange, as well as the effectiveness of managing connections between network communication devices, user communication devices, or any combination thereof. In some wireless communication systems, it may be desirable to deploy RIS (Relational Infrastructure Components) to support wireless communication over the THz RF spectrum and mitigate or reduce these problems. Summary of the Invention

[0004] Methods and apparatus for THz broadband RIS devices are disclosed.

[0005] In one embodiment, a RIS device includes a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the reconfigurable intelligent surface device to: transmit control signaling indicating a set of operating frequencies supported by the reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receive a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0006] In some embodiments, the reconfigurable intelligent surface device includes a metasurface including a plurality of meta-atoms. Each meta-atom includes a symmetric split ring layer having a structure of a symmetric split ring, and wherein the symmetric split ring is composed of a metallic material and at least two symmetric slices.

[0007] the metallic material and the at least two symmetric slices are configured to form a ring-shaped circuit based at least in part on a temperature of the at least two symmetric slices satisfying a temperature threshold - e.g., the temperature of the at least two symmetric slices exceeding a temperature critical point. The ring-shaped circuit is configured to break based at least in part on the temperature of the at least two symmetric slices not satisfying the temperature threshold - e.g., the temperature of the at least two symmetric slices being below the temperature critical point.

[0008] In some embodiments, an outer radius of the ring-shaped circuit is 50 and a width of the ring-shaped circuit is 30 . An opening angle of each of the at least two symmetric slices is 20°. An orientation angle of each of the at least two symmetric slices is 0°.

[0009] In another embodiment, a method performed at a RIS device includes: transmitting control signaling indicating a set of operating frequencies supported by the reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receiving a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0010] In yet another embodiment, a base unit comprises: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and transmit a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0011] In some embodiments, the processor is further configured to transmit, via the transceiver, a set of power control parameters for UL transmission for at least one of the supported operating frequencies, and wherein the set of power control parameters for UL transmission for each supported operating frequency is determined according to the reflection efficiency of that supported operating frequency.

[0012] In yet another embodiment, a method performed at a base unit comprises: receiving control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and transmitting a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency. BRIEF DESCRIPTION OF DRAWINGS

[0013] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments illustrated in the drawings that are shown by way of example, and in which:

[0014] FIGS. 1(a) and 1(b) illustrate RIS devices;

[0015] FIGS. 2(a) and 2(b) illustrate three-dimensional view and cross-sectional view of a symmetric split ring structure of a superatom;

[0016] FIG. 2(c) illustrates a top view of a symmetric split ring structure of a superatom according to the present disclosure;

[0017] FIG. 3(a) illustrates simulation results of reflection amplitude of a superatom;

[0018] FIG. 3(b) illustrates simulation results of phase difference between superatoms.

[0019] Figures 4(a) to 4(d) simulation results showing a deflected light beam;

[0020] Figure 5 ​Fig. illustrates a structure of a terahertz communication system;

[0021] Figure 6 is a schematic flow chart illustrating an embodiment of a method;

[0022] Figure 7 is a schematic flow chart illustrating an embodiment of another method; and

[0023] Figure 8 is a schematic block diagram illustrating an apparatus according to an embodiment.

[0024] The description of elements in each figure can refer to elements of previous figures. The same numbers in all figures refer to the same elements, including alternative embodiments of the same elements. DETAILED DESCRIPTION

[0025] Figs. 1(a) and 1(b) illustrate a RIS device (100).

[0026] The RIS device (100) consists of an array (referred to as a metasurface) (110) and an array controller (120). As shown in Figs. 1(a) and 1(b), the metasurface includes a plurality of repeating units distributed over one or more panels, where each unit can be referred to as a meta-atom. The RIS device (100) operates as a repeater that is able to obtain (e.g., receive) a signal from a base station (130) (or another transmission-reception point (TRP)) and output (e.g., send, transmit, or reflect) the received signal to user communication devices such as UE1 (e.g., user 140-1), UE2 (e.g., user 140-2),..., UEn (e.g., user 140-n) when the network communication device— such as the base station (130)— is unable to send a signal (e.g., a downlink transmission) directly to the user communication devices. Figure 1(a) and 1(b) As shown, the metasurface includes a plurality of repeating units distributed over one or more panels, where each unit can be referred to as a meta-atom. The RIS device (100) operates as a repeater that is able to obtain (e.g., receive) a signal from a base station (130) (or another transmission-reception point (TRP)) and output (e.g., send, transmit, or reflect) the received signal to user communication devices such as UE1 (e.g., user 140-1), UE2 (e.g., user 140-2),..., UEn (e.g., user 140-n) when the network communication device— such as the base station (130)— is unable to send a signal (e.g., a downlink transmission) directly to the user communication devices.

[0027] The RIS device can be configured to control the radiation direction of a light beam (e.g., a THz light beam). The light beam steering function is explained using the Snell formula. The RIS device can control the radiation direction of a light beam based on the Snell formula given by equation (1):

[0028] (1)

[0029] where and define the incident angle and the reflection angle of the THz light beam, respectively; defines the operational wavelength of the THz light beam; defines the metasurface refractive index by the refractive index of the medium (e.g., air) above the designed metasurface, and corresponding to the phase gradient imparted by the metasurface.

[0030] Various aspects of the present disclosure can determine the refractive index of air (i.e., the medium above the metasurface is air) under a normally incident THz beam of light ) equals 1, where the normally incident THz beam of light means that the angle of incidence ) equals 0° (i.e., = 0). The above equation (1) can be simplified to equation (2):

[0031] (2).

[0032] As a result, the reflection angle (which indicates the radiation direction or deflection direction) of the reflected THz beam of light can be determined according to equation (3):

[0033] (3).

[0034] Therefore, the radiation direction of the THz beam of light reflected by the RIS device (particularly, by the metasurface) can be tuned by changing the phase gradient ).

[0035] Under the condition of specular reflection, the reflection angle equals the angle of incidence. Due to the properties of the metasurface, when the THz beam of light is reflected by the metasurface, a turning angle is added to the reflection angle. This means that the reflection direction is deflected or turned by the turning angle caused by the metasurface. That is, the actual reflection angle of the THz beam of light reflected by the metasurface equals the sum of the reflection angle and the turning angle. In the present disclosure, the angle of incidence equals 0°. Therefore, the turning angle and the actual reflection angle have the same value. In the following description, the actual reflection angle is referred to as the reflection angle. In other words, in the following description, the reflection angle and the turning angle have the same value.

[0036] Various aspects of the present disclosure are directed to an RIS device supporting THz broadband (e.g., 0.735-0.965 THz), where the metasurface of the RIS device can be based on vanadium dioxide . For example, each meta-atom shown in FIG. 1(b) can be a meta-atom. The meta-atoms can be controlled by a controller (120) to control the radiation direction of the reflected THz beam of light. A field programmable gate array (FPGA), which can be used as the controller (120), can input a sequence to digitally compile the metasurface to change the phase gradient of the metasurface in the THz broadband, where the THz broadband includes an operational bandwidth.

[0037] ​Figures 2(a) and 2(b) show each superatom (200) of the super surface according to the present disclosure An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2 An example of the symmetric split-ring structure of a superatom (200). Figure 2(a) shows a three-dimensional view, and Figure 2(b) shows a cross-sectional view. As shown in Figures 2(a) and 2(b), each superatom (200) contains three layers: a metal (e.g., gold) reflecting layer at the bottom (at the bottom in Figure 2(a) and the right side in Figure 2(b)), which can have a thickness of, for example, 0.2

[0038] The opening angle (Θ ) refers to the angle each piece occupies within the ring. The orientation angle (Φ ) refers to the angle between the x-axis and the angle bisector of the opening angle of each piece.

[0039] has unique properties, that is, it has different states at different temperatures. When the temperature is lower than a temperature critical point (e.g., 60°), it can be considered as insulating (in an insulating state). When the temperature exceeds the temperature critical point (e.g., 60°), it is metallic (in a metallic state). When is in the metallic state, a metallic ring circuit is formed by the metallic (e.g., gold) material and the in the metallic state. When is in the insulating state, the structure of the ring circuit is destroyed. Therefore, the equivalent circuit when is in the metallic state and the equivalent circuit when is in the insulating state are completely different. Due to the difference, the superatoms in the insulating state There is a phase gradient (or phase difference) between superatoms in the insulating state and superatoms in the metallic state.

[0040] The temperature of the superatoms can be controlled by external excitations, such as bias voltage, excitation current, etc. For example, a controller can apply different bias voltages to different superatoms, such that the temperature of each superatom can be controlled to be in the metallic state (e.g., the temperature of the superatom exceeds the temperature critical point) or the insulating state (e.g., the temperature of the superatom is below the temperature critical point).

[0041] In the metallic state, the superatoms have a phase of 0°. In the insulating state, the superatoms have a phase of 180°. There is a phase gradient (or phase difference) between superatoms in the insulating state and superatoms in the metallic state.

[0042] A top view of an example superatom (200) is shown in FIG. 2(c). The symmetric split ring layer includes gold material and two symmetric slices. The length of each side of the square of the superatom is 140 nm. The outer radius (r) of the ring is 50 nm; and the width (w) of the ring is 30 nm. The opening angle (a) is 20°. The orientation angle (b) is 0°.

[0043] The conductivity in the insulating state can be 200 S / m; and The conductivity in the metallic state can be 200,000 S / m.

[0044] According to simulations, as shown in FIG. 3(a), the reflection amplitude of the superatom, where is in the insulating state or the metallic state, exceeds 0.7 in the THz range. In addition, as shown in FIG. 3(b), when the frequency is between 0.735-0.965 THz, the phase difference between the superatom in the insulating state and the superatom in the metallic state reaches 180° ± 20°.

[0045] In a THz communication system, the higher the reflection efficiency of the metasurface, the higher the beam deflection efficiency, and the better the transmission performance of the communication system. Binary bit reflectivity (BBRR) can be used to evaluate the reflection efficiency of the metasurface. BBRR is defined as where and is when is in the insulating state and when​​​ The complex reflectivity when in the metallic state. This means that BBRR is and The modulus of the difference between them divided by the modulus of their sum. Under ideal conditions, (when is in the insulating state) and (when is in the metallic state) have the same amplitude and a phase difference . Therefore, under ideal conditions, and the sum is zero and BBRR is infinite. Under real conditions, and the sum corresponds to the component of the unwanted specular reflection. This means that under real conditions and the sum is not zero, i.e. is not zero.

[0046] The present disclosure proposes that when is used in a metasurface, BBRR should be greater than a threshold value, for example BBRR > 5, to ensure that the metasurface is able to meet the reflection requirements.

[0047] According to equation (3) above, the simulation of the RIS superatoms shows that, based on the data shown in Figure 3(a) and 3(b) in the frequency band 0.735-0.965 THz, BBRR is all greater than 5 and reaches a peak of 33.5 at 0.905 THz, which means that the proposed metasurface comprising superatoms, each of which has a symmetric split ring structure, meets the conditions for beam deflection.

[0048] Based on the simulation results in Figure 3(a), when For different frequencies (i.e., for different bands), the reflection efficiency is different. Ideally, the reflection efficiency is expected to be 100%, i.e., all the energy of the incident light beam can be reflected by the metasurface without loss. However, based on the simulation results in FIG. 3(a), it is impossible to achieve 100% reflection efficiency. Considering that the RIS device is used to improve coverage and provide a strong path for some UEs that are outside the coverage of the gNB, the reflection efficiency is important for the gNB to determine the transmission power of the DL signal and configure a proper set of power control parameters for UL transmission. That is, for a wideband RIS device, different operating frequencies (or bands) have different reflection efficiencies. Therefore, for different operating frequencies (or bands), the transmission power of the DL signal should be determined by the reflection efficiency corresponding to the operating frequency (or band). In addition, for different operating frequencies (or bands), the gNB should configure the UE with a set of power control parameters for UL transmission corresponding to the operating frequency (or band), where the UE sends the UL signal to the gNB via the RIS device.

[0049] Accordingly, the RIS device should report the supported operating frequencies (or bands) and the reflection efficiency for each of the supported frequencies (or bands) to the gNB. For example, the RIS device includes a processor and a transceiver, and the processor is configured to send the supported operating frequencies and the reflection efficiency for each of the supported frequencies to the gNB via the transceiver.

[0050] As shown in Table 1, an example of reporting the supported operating frequencies and the reflection efficiency for each of the supported frequencies is provided.

[0051]

[0052] Table 1

[0053] Based on the received supported operating frequencies and the reflection efficiency for each of the supported frequencies, when the gNB transmits a DL signal in the supported operating frequencies, the transmission power is determined according to the reflection efficiency for the supported operating frequencies. In addition, the gNB configures the UE with a set of power control parameters for UL transmission (via the RIS device) for at least one of the supported operating frequencies, where the set of power control parameters for UL transmission for each of the supported operating frequencies is determined according to the reflection efficiency for the supported operating frequency.

[0054] When there are different phase gradients among the meta-atoms of the metasurface, the metasurface exhibits different reflection angles.

[0055] An example of a metasurface is described below. The metasurface is composed of 324 meta-atoms, forming 18 18 array structure. Each superatom has a structure as shown in Fig. 2(c).

[0056] Each row of the super surface can be considered as a unit cell. This means that all superatoms in a row (e.g. 18 superatoms) are controlled together, i.e. the same external excitation is applied to all superatoms within one unit cell. For example, all superatoms in a row can be applied the same external excitation such that their temperature is below 60° and accordingly the ring circuit is broken for each superatom in the row. Alternatively, all superatoms in another row (different from the row) can be applied another same external excitation such that their temperature is above 60° and accordingly the ring circuit is formed for each superatom in the other row.

[0057] If ‘0’ indicates that all superatoms in a row are applied an external excitation such that their temperature is below 60° and ‘1’ indicates that all superatoms in a row are applied an external excitation such that their temperature is above 60°; then an 18-bit sequence can configure the temperatures of the 18 rows of the super surface, where each row has 18 superatoms.

[0058] The 18-bit sequence can be in a periodic manner. This means that after a number of ‘0’s, the same number of ‘1’s follows; and the period is twice the number of ‘0’s. For example, the 18-bit sequence can be ‘010101010101010101’ with a period of 2, which can be abbreviated as the sequence ‘01’. For another example, the 18-bit sequence can be ‘001100110011001100’ with a period of 4, which can be abbreviated as the sequence ‘0011’.

[0059] To investigate the effect of broadband THz beam deflection, a super surface comprising 18 The far-field scattering pattern of a super surface of 18 superatoms is simulated, which has an input sequence “0011” (i.e. the sequence ‘001100110011001100’) from 0.735 THz to 0.965 THz, where the superatoms in each row are identically coded as ‘0’ or ‘1’ according to the sequence “0011”. That is, if a row is input ‘0’, the temperatures of all superatoms in the row are applied an external excitation such that they are below 60°; and if a row is input ‘1’, the temperatures of all superatoms in the row are applied another external excitation such that they are above 60°. Figures 4(a) to 4(d) ​The simulation results are shown. Two deflected beams are observed at ±43.2° for 0.77 THz (Fig. 4(a)), ±38° for 0.857 THz (Fig. 4(b)), ±36° for 0.902 THz (Fig. 4(c)), and ±33° for 0.965 THz (Fig. 4(d)), respectively.

[0060] The reflection angle of the light beam imparted by the metasurface can be controlled by different sequences. This means that each sequence corresponds to a certain reflection angle of a predetermined frequency, which can be pre-calculated and stored in the FPGA. When it is needed to deflect a certain angle (e.g., 36°) at a predetermined frequency (e.g., 0.902 THz), the corresponding sequence is retrieved from the FPGA and applied to the metasurface to achieve the required beam steering angle. The FPGA has an interface with the processor (e.g., digital baseband processor) in the RIS device to receive the information of the desired steering angle of the light beam and control the meta-atoms accordingly. The FPGA can be used to direct the light beam to the desired direction for any predetermined frequency within the wideband (e.g., 0.735-0.965 THz).

[0061] Figure 5 The structure of a THz communication system (500) is illustrated. As Figure 5 shown, the RIS device (in particular, the metasurface) (520) reflects the light beam from a base unit (e.g., gNB) (510) to a UE (530). The RIS device (520) includes an RIS controller (525) that functions as a processor and an FPGA. The THz light beam control is achieved by controlling the phase gradient of the meta-atoms of the metasurface. For example, a compiled sequence (e.g., a compiled sequence ID) is sent from the gNB (510) to the RIS controller (525). Based on the compiled sequence ID, the compiled sequence is retrieved from the FPGA to be applied to the metasurface. For example, each row of meta-atoms in the meta-atoms is applied with ‘0’ or ‘1’ such that a predetermined reflection angle (or steering angle) is obtained.

[0062] In a wireless communication system, the system coverage capability can be evaluated by link budget. Link budget is a calculation of all gains and losses in the transmitting end, communication link, propagation environment (atmosphere, coaxial cable, waveguide, optical fiber, etc.), and receiving end in a communication system. It is used to estimate the distance that a signal can successfully travel from the transmitting end to the receiving end.

[0063] Equation (4) is a simplified formula for calculating the link budget: where is the link margin, is the transmit power, is the transmit antenna gain, is the receive antenna gain, and H is the low noise amplifier gain (the receive antenna and low noise amplifier are in the UE). is the noise power in the transmission, is the demodulation receive threshold, is the loss of the RIS metasurface, and L is the path loss in free space. The free space loss describes the energy loss of an electromagnetic wave as it travels through air.

[0064] Equation (5) is the calculation of path loss where D is the distance in kilometers, is the frequency and C is the speed of light. It can be seen that for a certain distance, the higher the frequency, the greater the loss.

[0065] The RIS metasurface in the THz band has a low reflection efficiency. When the reflection amplitude is 70%, the energy efficiency is about 20% (which is equivalent to , which is used in the link budget for analysis. According to the link loss equation (5), at an energy efficiency of 20%, if = 0.85 THz, the maximum transmission distance is about 112 m (without considering atmospheric attenuation). This distance satisfies indoor short-range wireless communication.

[0066] Figure 6 is a schematic flowchart illustrating an embodiment of a method 600 according to the present application. In some embodiments, the method 600 is performed by an apparatus, such as a RIS device. In certain embodiments, the method 600 can be performed by a processor executing program code - e.g., a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

[0067] The method 600 can comprise: 602 transmitting control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and 604 receiving a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0068] In some embodiments, the reconfigurable intelligent surface device comprises a metasurface comprising a plurality of meta-atoms. Each meta-atom comprises a symmetric split ring layer having a structure of a symmetric split ring, and wherein the symmetric split ring is composed of a metallic material and at least two symmetric slices.

[0069] The metallic material and the at least two symmetric slices are configured to form a ring circuit based at least in part on a temperature of the slices satisfying a temperature threshold - e.g., the temperature of the slices exceeding a temperature critical point. The ring circuit is configured to form a ring circuit based at least in part on a temperature of the the temperature of the temperature critical point - and disconnect. The temperature of the temperature critical point - and disconnect.

[0070] In some embodiments, the outer radius of the ring-shaped circuit is 50 and the width of the ring-shaped circuit is 30 . The opening angle of each of the at least two symmetric slices is 20°. The orientation angle of each of the at least two symmetric slices is 0°.

[0071] Figure 7 is a schematic flow chart illustrating an embodiment of a method 700 according to the present application. In some embodiments, the method 700 is performed by an apparatus, such as a base unit. In certain embodiments, the method 700 can be performed by a processor, e.g., a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like, executing program code.

[0072] The method 700 can comprise: 702 receiving control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and 704 transmitting a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0073] In some embodiments, the method further comprises: transmitting a set of power control parameters for UL transmissions for at least one of the supported operating frequencies, wherein the set of power control parameters for UL transmissions for each supported operating frequency is determined according to the reflection efficiency of the supported operating frequency.

[0074] Figure 8 is a schematic block diagram illustrating an apparatus according to one embodiment.

[0075] With reference to Figure 8 , the RIS device comprises a processor, a memory, and a transceiver, which is a transmitter and / or a receiver. The processor implements the functions, processes, and / or methods presented in Figure 6 .

[0076] A RIS device comprising: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the reconfigurable intelligent surface device to: transmit control signaling indicating a set of operating frequencies supported by the reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receive a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0077] In some embodiments, the reconfigurable intelligent surface device comprises a metasurface comprising a plurality of meta-atoms. Each meta-atom comprises a symmetric split ring layer having a structure of a symmetric split ring, and wherein the symmetric split ring is composed of a metallic material and at least two symmetric slices.

[0078] The metallic material and the at least two symmetric slices are configured to form a ring-shaped circuit based at least in part on a temperature of the metallic material satisfying a temperature threshold - e.g., the temperature of the metallic material exceeding a temperature critical point. The ring-shaped circuit is configured to break based at least in part on the temperature of the metallic material not satisfying the temperature threshold - e.g., the temperature of the metallic material being below the temperature critical point. The temperature of the metallic material can be controlled by an external stimulus. In some embodiments, an outer radius of the ring-shaped circuit is 50 and a width of the ring-shaped circuit is 30 . An opening angle of each of the at least two symmetric

[0079] slices is 20°. An orientation angle of each of the at least two symmetric slices is 0°. A gNB (i.e., a base unit) comprises a processor, a memory, and a transceiver, and the transceiver is a transmitter and / or a receiver. The processor implements the functions, procedures, and / or methods proposed in .

[0080] The base unit comprises a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and transmit a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency. Figure 7

[0081] The base unit comprises a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and transmit a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

[0082] ​​In some embodiments, the processor is further configured to transmit, via the transceiver, a set of power control parameters for UL transmission for at least one of the supported operating frequencies, and wherein the set of power control parameters for UL transmission for each supported operating frequency is determined according to a reflection efficiency of the supported operating frequency.

[0083] The present disclosure also proposes an RIS device for THz transmission, comprising a metasurface consisting of a plurality of meta-atoms, each meta-atom comprising a symmetric split ring layer having a structure of symmetric split rings, the symmetric split rings consisting of a metallic material and two symmetric pads. In some embodiments, the RIS device comprises a metasurface consisting of a plurality of meta-atoms, each meta-atom comprising a symmetric split ring layer having a structure of symmetric split rings, the symmetric split rings consisting of a metallic material and two symmetric pads. In some embodiments, when the temperature of the metallic material exceeds a temperature critical point, the metallic material and the two symmetric pads form a ring circuit, and when the temperature of the metallic material is below the temperature critical point, the ring circuit is broken. The temperature of the metallic material can be controlled by external excitation. In some embodiments, the outer radius of the ring is 50 ; and the width of the ring is 30 In some embodiments, the opening angle of each pad is 20°, and the orientation angle of each pad is 0°.

[0084] As those skilled in the art will appreciate, some aspects of the embodiments can be embodied as a system, a device, a method or a program product. Accordingly, the embodiments can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that can all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, the embodiments can take the form of a program product embodied in one or more computer readable storage devices storing machine-readable code, computer readable code, and / or program code, hereinafter referred to as code. The storage devices can be tangible, non-transitory, and / or non-transmission. The storage devices can not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

[0085] Certain of the functional units described in this specification can be labeled as "modules," in order to more particularly emphasize their implementation independence. For example, a module can be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module can also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[0086] Modules can also be implemented in code and / or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but the module can include disparate instructions stored in different locations which, like a file, a section of a file, or a department store, logically group the instructions together when executed.

[0087] Indeed, a module of code can include a single instruction, or many instructions, and can even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data can be identified within the modules and illustrated as being stored in memory, but such data can be stored in any

[0088] Any combination of one or more computer readable medium can be utilized. The computer readable medium can be a computer readable storage medium. The computer readable storage medium can be a storage device storing the code. The storage device can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0089] A non-exhaustive list of more specific examples of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0090] Code for carrying out operations for embodiments can include any number of lines and any combination of lines, including any number of lines of code in any combination of programming languages, including an object-oriented programming language such as the Python, Ruby, Java, Smalltalk, C++, or the like and conventional procedural programming languages, such as the "C" programming language, or the like, and / or machine languages such as assembly languages. The code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0091] Reference throughout this specification to "one embodiment", "an embodiment", or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment", "in an embodiment", and similar language throughout this specification may, but not

[0092] Furthermore, the described features, structures, or characteristics of the various embodiments can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the embodiments can be practiced without one or more of the

[0093] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function specified in the flowchart diagrams and / or block diagrams block or blocks.

[0094] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function specified in the flowchart diagrams and / or block diagrams block or blocks.

[0095] The code can also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions specified in the flowchart diagrams and / or block diagrams block or blocks.

[0096] The flow diagrams and / or block diagrams in the drawings are illustrative of the architectures, functional operations and / or steps with regard to the possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the flow diagrams and / or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical functions.

[0097] It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods can be conceived that are equivalent in function, logic, or effect to those illustrated, with the possession of equivalents structures, functions, results, and / or objects.

[0098] Although various arrow types and line types can be employed in the flowcharts and / or block diagrams, these are understood to be taken in a descriptive sense in which there can be any quantity of devices arranged to perform the functions, and each line that can be drawn may

[0099] The layers of the radio interface protocol can be implemented by the processor. The memory is connected with the processor to store various pieces of information for driving the processor. The transceiver is connected with the processor to transmit and / or receive a radio signal. Of course, the transceiver can be implemented as a transmitter for transmitting a radio signal and a receiver for receiving a radio signal.

[0100] The memory can be located inside or outside the processor, and connected with the processor through various well-known means.

[0101] In the above-described embodiments, components and features of the embodiments are combined in a predetermined form. Each component or feature should be considered selective unless explicitly specified otherwise. Each component or feature can be implemented as not associated with other components or features. Also, a new embodiment can be configured by combining some components and / or features. The order that operations described in the embodiments can be changed. Some components or features of any embodiment can be included in another embodiment or replaced with components and features corresponding to another embodiment. It is obvious that claims not explicitly cited in the claims are combined to form embodiments or included in new claims.

[0102] The embodiments can be implemented by hardware, firmware, software, or a combination thereof. In the case of implementation by hardware, the exemplary embodiments described herein can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, etc., according to hardware implementation.

[0103] The embodiments can be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. Therefore, the scope of the application is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A reconfigurable intelligent surface device, comprising: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the reconfigurable intelligent surface device to: transmit control signaling indicating a set of operating frequencies supported by the reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receive a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

2. The reconfigurable intelligent surface device of claim 1, wherein, The reconfigurable intelligent surface device comprises a metasurface comprising a plurality of meta-atoms.

3. The reconfigurable intelligent surface device of claim 2, wherein, Each superatom comprises a symmetric split ring layer having a structure of symmetric split rings, and wherein the symmetric split rings are formed of a metallic material and at least two symmetric pieces.

4. The reconfigurable intelligent surface device of claim 3, wherein, the metal material and the at least two symmetrical The sheet is configured to form a looped circuit based at least in part on a temperature of the metal material satisfying a temperature threshold.

5. The reconfigurable intelligent surface device of claim 4, wherein, The ring circuit is configured to be disconnected based at least in part on the temperature of the not satisfying the temperature threshold.

6. The reconfigurable intelligent surface device of claim 4, wherein, The The temperature is controlled by external excitation.

7. The reconfigurable intelligent surface device of claim 4, wherein, The outer radius of the ring circuit is 50 The width of the ring circuit is 30 .

8. The reconfigurable intelligent surface device of claim 3, wherein, the at least two symmetrical The opening angle of each of the blades is 20°.

9. The reconfigurable intelligent surface device of claim 3, wherein, the at least two symmetrical the orientation angle of each of the pieces is 0°.

10. A base unit, comprising: a transceiver; and a processor coupled to the transceiver, wherein the processor is configured to cause the base unit to: receive control signaling indicating a set of operating frequencies supported by a reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and transmit a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

11. The base unit of claim 10, wherein the processor is further configured to cause the base unit to transmit a set of power control parameters for UL transmissions for at least one of the supported operating frequencies, and wherein the set of power control parameters for UL transmissions for each supported operating frequency is determined from the reflection efficiency of the supported operating frequency.

12. A method performed at a reconfigurable intelligent surface device, comprising: transmitting control signaling indicating a set of operating frequencies supported by the reconfigurable intelligent surface device and a set of reflection efficiencies associated with the set of operating frequencies; and receiving a transmission on an operating frequency of the set of operating frequencies supported by the reconfigurable intelligent surface device and using a transmit power based on the reflection efficiency associated with the operating frequency.

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