Systems and methods for wireless communication using configurable surfaces

Abstract

Various aspects of the present invention utilize a prism-like effect occurring in a reconfigurable intelligent surface (RIS), wherein the RIS reflects incident signals of different frequencies in different directions to determine the characteristics of a channel between a transmitter and a receiver, wherein the channel includes the RIS. Specifically, this may include estimating the angle of arrival (AoA) of the RIS in uplink transmission or estimating the angle of departure (AoD) from the RIS in downlink transmission. Various aspects of the present invention also provide schemes for compensating for the prism effect in broadband transmissions, particularly at high frequencies (e.g., millimeter waves and THz).

Description

Technical Field

[0001] This invention generally relates to wireless communication, and in certain embodiments, is designed to use configurable surfaces to reflect wireless signals between a transmitter and a receiver. Background Technology

[0002] In some wireless communication systems, user equipment (UE) communicates wirelessly with a base station (or gNB) to send and / or receive data from the base station. Wireless communication from the UE to the base station is called uplink (UL) communication. Wireless communication from the base station to the UE is called downlink (DL) communication. Wireless communication from one UE to another is called sidelink (SL) communication or device-to-device (D2D) communication.

[0003] Performing uplink, downlink, and sidelink communications requires resources. For example, a base station can wirelessly transmit data to a UE in a downlink transmission, such as a transport block (TB), at a specific frequency and for a specific duration. The frequency and time period used are examples of resources.

[0004] For uplink or downlink transmissions, beamforming is a technique that directs a wireless signal toward a specific receiving device, rather than propagating the signal in a wider direction. Beamforming is an important aspect of 5G networks. One technique for beamforming a signal involves using multiple adjacent antennas, all broadcasting the same signal at slightly different times. The interference produced by the overlapping transmitted waves is constructive in some areas, making the signal stronger, while it is destructive in other areas, making the signal weaker or canceling it out. Summary of the Invention

[0005] According to one aspect of the present invention, a method is provided, involving transmitting first configuration information to user equipment (UE), the first configuration information identifying the reference signal and a carrier frequency of the reference signal, the reference signal and the carrier frequency being used to determine channel information regarding a channel between a base station and the UE via a reconfigurable intelligent surface (RIS). The method further includes: transmitting a reference signal redirected by the RIS based on second configuration information, the second configuration information configuring the RIS to redirect different frequency components of the reference signal in different directions. The method further includes: receiving measurement information from the UE relating to measurements of the reference signal redirected by the RIS, and determining the channel information based on the transmitted reference signal and the received measurement information.

[0006] According to one aspect of the present invention, an apparatus comprising a processor and a computer-readable medium is provided. The computer-readable medium stores computer-executable instructions, which, when executed, cause the processor to: send first configuration information to a UE, the first configuration information identifying the reference signal and a carrier frequency of the reference signal, the reference signal and the carrier frequency being used to determine channel information regarding a channel between a base station and the UE via a RIS; send a reference signal redirected by the RIS based on second configuration information, the second configuration information configuring the RIS to redirect different frequency components of the reference signal in different directions; receive measurement information from the UE relating to measurements of the reference signal redirected by the RIS; and determine the channel information based on the sent reference signal and the received measurement information.

[0007] According to one aspect of the present invention, a method is provided, relating to: a UE receiving configuration information, the configuration information identifying the reference signal and a carrier frequency of the reference signal, the reference signal and the carrier frequency of the reference signal being used to determine channel information regarding a channel between a base station and the UE via a RIS (Reference Information System). The method further relates to: the UE receiving a reference signal that has been redirected by the RIS; and the UE measuring the received reference signal. The method further relates to: transmitting measurement information related to the measurement of the received reference signal.

[0008] In some embodiments, the UE also receives data that has been redirected by the RIS.

[0009] In some embodiments, the UE receives at least one of the following: one or more narrowband reference signals, redirected by the RIS in different directions such that reflected beams from the RIS do not substantially overlap; one or more narrowband reference signals, redirected by the RIS in different directions such that reflected beams from the RIS overlap; or a wideband reference signal, wherein the frequency components of the wideband reference signal are redirected by the RIS in different directions due to a prism-like effect of the RIS.

[0010] In some embodiments, the UE compensates for the multipath fading effect caused by the redirection of frequency components in a wideband reference signal occupying a certain frequency range by the RIS in different directions by receiving an indication to perform channel equalization to compensate for the multipath fading effect.

[0011] In some embodiments, measuring the received reference signal includes measuring at least one of the following: the frequency response of the received wideband reference signal; the reference signal received power (RSRP) of one or more reference signals; the reference signal strength indicator (RSSI) of one or more reference signals; the reference signal received quality (RSRQ) of one or more reference signals; or the signal-to-noise ratio (SNR) of one or more reference signals.

[0012] In some embodiments, transmitting measurement information includes transmitting at least one of the following: an identifier of one or more reference signals having a received reference signal strength that satisfies a minimum threshold; a measurement of the reference signal received power (RSRP) of one or more reference signals; a measurement of the reference signal strength indicator (RSSI) of one or more reference signals; a measurement of the reference signal received quality (RSRQ) of one or more reference signals; a measurement of the signal-to-noise ratio (SNR) of one or more reference signals; or the frequency response of a received wideband reference signal.

[0013] In some embodiments, receiving the configuration information includes receiving one or more of the following: an indication that the RIS is being used to redirect signaling to the UE; an indication of the type of RIS used to redirect signaling to the UE; an identifier of the carrier frequency used to transmit the reference signal; or an identifier of the bandwidth of the reference signal.

[0014] According to one aspect of the present invention, an apparatus comprising a processor and a computer-readable medium is provided. The computer-readable medium stores computer-executable instructions that, when executed, cause the processor to: receive configuration information identifying a reference signal and a carrier frequency of the reference signal, the reference signal and the carrier frequency being used to determine channel information regarding a channel between a base station and a UE via a reconfigurable intelligent surface (RIS); receive a reference signal that has been redirected by the RIS; measure the received reference signal; and transmit measurement information relating to the measurement of the received reference signal.

[0015] According to one aspect of the invention, a method is provided, involving a RIS receiving first configuration information for configuring the RIS to redirect different frequency components of a reference signal in different directions. The method also involves receiving a reference signal from a transmitter and redirecting the received reference signal to a receiver based on the first configuration information.

[0016] In some embodiments, the method further includes: the RIS receiving second configuration information for configuring the RIS to redirect data transmission in an appropriate direction when data transmission interacts with the RIS.

[0017] In some embodiments, the method further includes at least one of the following: receiving the data transmission from the transmitter; or redirecting the received data transmission in the direction of the receiver based on the second configuration information.

[0018] In some embodiments, receiving the reference signal includes receiving at least one of the following: one or more narrowband reference signals, redirected by the RIS in different directions such that reflected beams from the RIS do not substantially overlap; one or more narrowband reference signals, redirected by the RIS in different directions such that reflected beams from the RIS overlap; and a wideband reference signal, wherein the frequency components of the wideband reference signal are redirected by the RIS in different directions due to a prism-like effect of the RIS.

[0019] In some embodiments, the method further includes: compensating for multipath fading effects caused by the redirection of frequency components in a broadband reference signal occupying a certain frequency range in different directions by the RIS in order to reduce deviation from the main desired direction.

[0020] In some embodiments, configuring the RIS to reduce deviation from the desired direction includes configuring the RIS using third configuration information, the third configuration information including configuration information of at least one of the following: configuring the RIS to redirect broadband data signals transmitted in a wide beam, the wide beam being larger than the deviation caused by a prism-like effect; configuring the RIS to divide the RIS into separate portions, each portion redirecting a subset of the broadband data signals incident on the RIS; and configuring the RIS such that different sets of one or more configurable elements of the RIS redirect the broadband data signals incident on the RIS in the desired direction by: configuring the configurable elements at one end of the RIS to redirect the lowest frequency component of the broadband data signals in the desired direction, and then gradually changing the configuration of the other configurable elements of the RIS such that at the other end of the RIS, the configurable elements are configured to redirect the highest frequency of the broadband data signals in the desired direction.

[0021] In some embodiments, receiving the first configuration information includes receiving one or more of the following: the carrier frequency used to transmit the reference signal; the AoA of the reference signal for downlink transmission at the RIS; one or more assumed AoDs of the reference signal from the RIS when the reference signal is redirected for downlink transmission; one or more assumed AoAs of the reference signal for uplink transmission at the RIS; the AoD of the reference signal from the RIS when the reference signal is redirected for uplink transmission; the beamwidth of the signal being redirected; and the division of the RIS to redirect reference signals of different frequencies.

[0022] According to one aspect of the present invention, an apparatus comprising a processor and a computer-readable medium is provided. The computer-readable medium stores computer-executable instructions that, when executed, cause the processor to: receive configuration information for configuring the RIS to redirect different frequency components of a reference signal in different directions; receive the reference signal from a transmitter; and redirect the received reference signal to a receiver based on the configuration information.

[0023] In addition to the methods described above that typically involve downlink channel estimation and data transmission over channels including RIS, aspects of the present invention can also be applied to uplink channel estimation and data transmission over channels including RIS, as well as sidelink channel estimation and data transmission over channels including RIS.

[0024] Additional aspects of the invention also include devices such as base stations, user equipment, and RIS according to the embodiments appended herein.

[0025] In some embodiments of the invention, a planar array of configurable elements, such as a Reflection Array (RIS), is used in the path of the communication link between the base station and the user equipment to redirect transmissions. This allows the RIS to intentionally reflect in multiple directions, for example, when using a narrow band, or when using a wide band signal, due to deviations in certain frequency components. Simultaneous reflection effectively reduces the beam scanning process performed at the receiver. Furthermore, for some materials used in the RIS (e.g., liquid crystal), the response time between applying a bias voltage to the elements in the RIS and completing the reconfiguration of the elements to reflect in another direction is long. Therefore, reducing the overhead of simultaneous reflection helps to improve the time available for reconfiguring the RIS.

[0026] Furthermore, in the case of broadband transmission, the base station notifies the UE of the use of RIS in the communication channel. This is because RIS makes the channel appear as a multipath fading channel, even though at high frequencies the channel is typically flat with less scattering. The channel appears as a multipath fading channel because frequencies in broadband transmission can be redirected in several different directions due to a prism-like effect, which will be described in more detail below. Attached Figure Description

[0027] To provide a more comprehensive understanding of the embodiments of the present invention and their advantages, the following description is given with reference to the accompanying drawings, in which:

[0028] Figure 1 This is a schematic diagram of a transmission channel between a source and a destination according to one aspect of the invention, wherein a planar array of configurable elements is used to redirect signals.

[0029] Figure 2 This is a schematic diagram of a communication system that may occur in an embodiment of the present invention;

[0030] Figure 3A , Figure 3B and Figure 3C These are block diagrams of an exemplary user equipment, a base station, and a RIS.

[0031] Figure 4A This is a schematic diagram of how RIS is used to redirect two different frequency transmission signals sent by a base station in two different directions.

[0032] Figure 4B It is as follows Figure 4A A graphical representation of the angle of departure (AoD) of two different frequency signals in the RIS redirection configuration.

[0033] Figure 5A This is a graphical representation of three different frequencies of AoD redirected by RIS.

[0034] Figure 5B RIS is used to redirect frequencies transmitted by the base station in multiple different directions (e.g., Figure 5A A schematic diagram (as shown).

[0035] Figure 5C This is a graphical representation of three different frequencies of AoD (Aspect of Arrival) redirected by RIS at different angles of arrival (AoA), resulting in the AoD range being... Figure 5A Compared to the previous version, it is reduced.

[0036] Figure 6A This is a graphical representation of the normalized gain of the corresponding AoD of the signal redirected by the RIS, which has been divided into four distinct parts, each used to redirect the signal with a different bias voltage.

[0037] Figure 6B This is a graph showing the relationship between the mean squared error and the AoD estimate for a given frequency redirected by RIS.

[0038] Figure 7 According to one aspect of this application, this is a signal flow diagram of signaling between the base station, RIS, and UE for downlink configuration and data transmission.

[0039] Figure 8 According to one aspect of this application, this is a signal flow diagram of signaling between the base station, RIS, and UE for uplink configuration and data transmission. Detailed Implementation

[0040] For illustrative purposes, specific exemplary embodiments are explained in more detail below with reference to the accompanying drawings.

[0041] The embodiments described herein illustrate information sufficient to practice the claimed subject matter and explain methods for practicing such subject matter. Upon reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of the claimed subject matter and recognize that the application of these concepts is not specifically mentioned herein. It should be understood that these concepts and applications are within the scope of this invention and the appended claims.

[0042] Furthermore, it should be understood that any module, component, or device disclosing the executable instructions herein may include or otherwise access one or more non-transitory computer / processor-readable storage media for storing information, such as computer / processor-readable instructions, data structures, program modules, and / or other data. A non-exhaustive list of examples of non-transitory computer / processor-readable storage media includes magnetic tape cassettes, magnetic tape, disk storage or other magnetic storage devices, compact disc read-only memory (CD-ROM), digital video disc or digital versatile disc (i.e., DVD), Blu-ray disc™ and other optical discs, or other optical storage devices; volatile and non-volatile, removable and non-removable media implemented in any method or technology; random-access memory (RAM); read-only memory (ROM); electrically erasable programmable read-only memory (EEPROM); flash memory or other storage technologies. Any of these non-transitory computer / processor-readable storage media may be part of a device or may be accessed or connected to a device. Computer / processor-readable / executable instructions used to implement the applications or modules described herein may be stored by such non-transitory computer / processor-readable storage media or otherwise preserved.

[0043] Reconfigurable intelligent surfaces (RIS), also known as large intelligent surfaces (LIS), intelligent reflective arrays, intelligent passive mirrors, artificial wireless spaces, reconfigurable metasurfaces, and holographic multiple input multiple output (MIMO), are arrays of configurable elements. These configurable elements can also be called metamaterial units or unit cells. Metamaterials (or Beyond-Material) are materials engineered to alter their properties, thereby manipulating the amplitude and / or phase of waves incident on them. Amplitude and / or phase can be manipulated by changing the impedance or relative permittivity (and / or permeability) of the metamaterial. At low frequencies, impedance is controlled by lumped elements such as PIN diodes, variable capacitors, transistors, or microelectromechanical systems (MEMS). At high frequencies, the relative permittivity and / or permeability of material elements (such as liquid crystals at high frequencies and graphene at even higher frequencies) change their permittivity according to variations in the bias voltage applied to the material. Therefore, the phase of the signal redirected by the material changes according to the change in dielectric constant. Because the bias voltage involved in these materials is quite low, they are often called passive phase shifters.

[0044] In some discussions of this invention, the RIS device may be referred to as a set of configurable elements arranged in a linear or planar array. However, the analysis and discussion can be extended to other two-dimensional or three-dimensional arrangements (e.g., circular arrays). A linear array is a vector of N configurable elements, and a planar array is a matrix of N×M configurable elements. These configurable elements are capable of redirecting waves / signals incident on the linear or planar array by changing the phase of the wave / signal. The configurable elements are also capable of changing the amplitude, polarization, and even frequency of the wave / signal. In some planar arrays, these changes are caused by changing the bias voltage, which controls the individual configurable elements of the array via control circuitry connected to the linear or planar array. The control circuitry capable of controlling the linear or planar array can be connected to a communication network, to which base stations and UEs communicating with each other are part. For example, the network controlling the base station can also provide configuration information to the linear or planar array. Control methods other than bias voltage control include, but are not limited to, mechanical deformation and phase change materials.

[0045] Because these control methods can manipulate incident waves, these types of devices are less expensive, and because they require less bias voltage, RIS has recently attracted widespread research interest in the field of wireless communications as a valuable tool for beamforming and / or modulating communication signals. Figure 1 A basic example of using RIS in beamforming is shown, where each RIS configurable element (unit cell) can change the phase of the incident wave from the source, such that the reflected waves from all RIS elements are aligned with the direction of the destination to increase or maximize its received signal strength (e.g., maximize SNR). This reflection via RIS can be called reflective array beamforming.

[0046] While RIS has been studied to some extent in the channel path between the transmitter and receiver, this study does not consider the prism-like effect that occurs in practical RIS implementations. The prism-like effect occurs because the characteristics of the RIS define the relationship between phase shift, frequency, and control methods (e.g., bias voltage), causing the RIS to redirect incident signals of different frequencies in different directions. From an optical perspective, a prism is a dispersive element used to separate white light into its constituent spectral wavelengths. In this context, the prism-like effect describes how, when different frequencies of incident communication beams with the same angle of arrival (AoA) strike the RIS, for the same bias voltage, these different frequencies have different angles of departure (AoD). This effect has been used in RIS for optical applications such as multicolor imaging and meta-lenses.

[0047] For the same applied bias voltage used to control RIS components, the phase shift of the incident wave differs at different frequencies. However, the difference in phase shift under different applied bias voltages is not necessarily linear. For example, for a given RIS, when the applied bias voltage is 1.1 volts, the phase shift is approximately 50 degrees at 125 GHz and approximately 275 degrees at 130 GHz. However, when 1.5 volts is applied, the phase shift is approximately 225 degrees at 125 GHz and approximately 360 degrees at 130 GHz.

[0048] In some implementations of RIS, a linear relationship between phase shift and frequency can be achieved over a range of applied voltages, but at the cost of a narrow bandwidth. For example, in a practical 100 GHz operating frequency range, the linear relationship between phase shift, frequency, and applied voltage might be around 4 GHz, which is not very useful within that range. It's important to note that the first derivative of the phase shift with respect to frequency is called the group delay. Only a linear relationship between phase shift and frequency can guarantee a constant group delay, ensuring that beams at different frequencies do not separate.

[0049] This invention provides a method and apparatus for providing a certain level of compensation for the prism-like effect of the aforementioned RIS, wherein the RIS reflects incident signals of different frequencies in different directions. This effect is more pronounced at high frequencies (e.g., sub-THz bands) due to the typically large transmission bandwidth used at these frequencies. This prism-like effect can also cause interference and multipath fading effects at the receiver. This application also utilizes the configuration of RIS to provide novel configuration signaling between devices in a communication network.

[0050] Various aspects of the present invention utilize the prism-like effect described above to determine the characteristics of a channel, wherein the channel includes a RIS (Real-Induced Spectrum). Specifically, this may include estimating the AoA (Aspect-Oriented Ability) of the RIS in uplink transmission or estimating the AoD (Aspect-Oriented Daughter) from the RIS in downlink transmission. Various aspects of the present invention provide schemes for compensating for the prism effect in broadband transmissions, particularly at high frequencies (e.g., millimeter waves and THz). Various aspects of the present invention provide novel signaling associated with the prism effect during estimation and transmission.

[0051] Figure 1 A planar array of configurable elements is shown in the channel between source 2 or transmitter and destination 6 or receiver (in Figures 4A-4B Examples are labeled RIS. The channel between source 2 and destination 6 includes the channel between source 2 and RIS 4, and the channel between RIS 4 and destination 6. For the i-th RIS configurable element (RIS unit), it is identified as h respectively. i and g i Where i∈{1,2,3,…,N*M}, and assume that RIS consists of N*M elements or unit cells. A wave leaving source 2 and arriving at RIS 4 can be said to arrive with a specific AoA. When a wave is reflected or redirected by RIS 4, it can be considered that the wave leaves RIS 4 with a specific AoD.

[0052] Although it has a two-dimensional planar array RIS 4 Figure 1 Channel h is shown i and channel g i However, the figure does clearly show the elevation and azimuth angles of the transmission from source 2 to RIS 4, and the elevation and azimuth angles of the redirected transmission from RIS 4 to destination 6. In the case of a linear array, it might be necessary to focus on only one angle, namely the azimuth angle.

[0053] In wireless communication, RIS4 can be deployed as (1) a reflector between a transmitter and a receiver, such as Figure 1 As shown, or (2) a transmitter (integrated at the transmitter) to help realize a virtual MIMO system, since RIS helps guide the signal from the feed antenna.

[0054] The following Figure 2 , Figure 3A and Figure 3B A network and device context is provided, which can be in a network and can implement aspects of the invention.

[0055] Figure 2 An exemplary communication system 100, in which embodiments of the present invention can be implemented, is illustrated. Typically, system 100 enables multiple wireless or wired components to transmit data and other content. The purpose of system 100 may be to provide content (voice, data, video, text) via broadcast, narrowcast, user equipment to user equipment, etc. System 100 can operate efficiently by sharing resources such as bandwidth.

[0056] In this example, the communication system 100 includes electronic devices (EDs) 110a to 110c, radio access networks (RANs) 120a and 120b, a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. Although Figure 2 A certain number of these components or elements are shown, but system 100 may include any reasonable number of these components or elements.

[0057] EDs 110a to 110c are used for operation, communication, or both in system 100. For example, EDs 110a to 110c are used for transmitting, receiving, or both via a wireless communication channel. Each of EDs 110a to 110c represents any suitable end-user equipment for wireless operation and may include (or be referred to as) devices such as: user equipment (UE), wireless transmit / receive unit (WTRU), mobile station, mobile subscriber unit, cellular telephone, station (STA), machine type communication (MTC) device, personal digital assistant (PDA), smartphone, laptop computer, computer, touchpad, wireless sensor, or consumer electronic device.

[0058] Figure 2An exemplary communication system 100, in which embodiments of the present invention can be implemented, is illustrated. Typically, the communication system 100 enables multiple wireless or wired components to transmit data and other content. The purpose of the communication system 100 may be to provide content (voice, data, video, text) via broadcast, multicast, unicast, user equipment to user equipment, etc. The communication system 100 can operate by sharing resources such as bandwidth.

[0059] In this example, the communication system 100 includes electronic devices (EDs) 110a to 110c, radio access networks (RANs) 120a and 120b, a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. Although Figure 2 A certain number of these components or elements are shown, but the communication system 100 may include any reasonable number of these components or elements.

[0060] EDs 110a to 110c are used for operation and / or communication in communication system 100. For example, EDs 110a to 110c are used for transmitting and / or receiving via wireless or wired communication channels. Each of EDs 110a to 110c represents any suitable end-user equipment for wireless operation and may include (or be referred to as) devices such as: user equipment (UE), wireless transmit / receive unit (WTRU), mobile station, fixed or mobile subscriber unit, cellular telephone, station (STA), machine type communication (MTC) device, personal digital assistant (PDA), smartphone, laptop computer, computer, tablet computer, wireless sensor, or consumer electronic device.

[0061] exist Figure 2In this configuration, RAN 120a and 120b include base stations 170a and 170b, respectively. Each base station 170a and 170b is used to establish a wireless connection with one or more EDs (EDs) from ED 110a to 110c, enabling access to any other base stations 170a and 170b, core network 130, PSTN 140, Internet 150, and / or other networks 160. For example, base stations 170a and 170b may include (or may be) one or more of several known devices, such as a base transceiver station (BTS), Node-B (NodeB), evolved NodeB (eNodeB), home eNodeB, gNodeB, transmission and receive point (TRP), site controller, access point (AP), or wireless router. Alternatively, any ED 110a to 110c may be used to connect, access, or communicate with any other base station 170a and 170b, Internet 150, core network 130, PSTN 140, other network 160, or any combination thereof.

[0062] EDs 110a to 110c and base stations 170a and 170b are examples of communication devices that can be used to implement some or all of the functions and / or embodiments described herein. Figure 2In the illustrated embodiment, base station 170a constitutes part of RAN 120a, which may include other base stations, one or more base station controllers (BSCs), one or more radio network controllers (RNCs), relay nodes, components, and / or devices. Any base station 170a, 170b may be a single component, as shown, or multiple components distributed within the corresponding RAN, etc. Furthermore, base station 170b forms part of RAN 120b, which may include other base stations, components, and / or devices. Each base station 170a and 170b transmits and / or receives radio signals within a specific geographical area or region (sometimes referred to as a "cell" or "coverage area"). A cell may be further divided into cell sectors; for example, base stations 170a and 170b may employ multiple transceivers to provide services to multiple sectors. In some embodiments, established picocells or femtocells supported by radio access technologies may exist. In some embodiments, multiple transceivers may be used for each cell, for example, using multiple-input multiple-output (MIMO) technology for each cell. The number of RANs 120a and 120b shown is merely exemplary. Any number of RANs can be considered when designing the communication system 100.

[0063] Base stations 170a and 170b use radio frequency (RF), microwave, infrared (IR), or other wireless communication links to communicate with one or more EDs 110a to 110c via one or more air interfaces 190. Air interface 190 can utilize any suitable wireless access technology. For example, communication system 100 can implement one or more orthogonal or non-orthogonal channel access methods in air interface 190, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA).

[0064] Base stations 170a and 170b can implement Universal Terrestrial Radio Access (UTRA) of the Universal Mobile Telecommunication System (UMTS) to establish an air interface 190 using Wideband CDMA (WCDMA). In this case, base stations 170a and 170b can implement protocols such as High Speed ​​Packet Access (HSPA), Evolved HPSA (HSPA+), and optionally High Speed ​​Downlink Packet Access (HSDPA), High Speed ​​Packet Uplink Access (HSUPA), or a combination of both. Alternatively, base stations 170a and 170b can use LTE, LTE-A, and / or LTE-B to establish an air interface 190 with Evolved UTMS Terrestrial Radio Access (E-UTRA). This is considering that communication system 100 can use multi-channel access capabilities, including those schemes described above. Other wireless technologies used for air interface implementation include IEEE 802.11, 802.15, 802.16, CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, IS-2000, IS-95, IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemes and wireless protocols can also be used.

[0065] RANs 120a and 120b communicate with core network 130 to provide various services, such as voice, data, and other services, to EDs 110a through 110c. RANs 120a and 120b and / or core network 130 may communicate directly or indirectly with one or more other RANs (not shown), which may (or may not) be directly served by core network 130 and may (or may not) employ the same radio access technology as RANs 120a, RAN 120b, or both. Core network 130 may also act as a gateway access between (i) RANs 120a and 120b and / or EDs 110a through 110c, and (ii) other networks (e.g., PSTN 140, Internet 150, and other networks 160).

[0066] EDs 110a to 110c communicate with one or more other EDs via one or more SL air interfaces 180 using wireless communication links (e.g., radio frequency (RF), microwave, infrared (IR), etc.). SL air interfaces 180 can utilize any suitable wireless access technology and can be substantially similar to air interface 190, through which EDs 110a to 110c communicate with one or more base stations 170a to 170c, or they can be significantly different. For example, communication system 100 can implement one or more channel access methods in SL air interface 180, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA). In some embodiments, SL air interface 180 can be implemented at least partially on unlicensed spectrum.

[0067] Additionally, some or all of EDs 110a to 110c may include the ability to communicate with different wireless networks via different wireless links using different wireless technologies and / or protocols. Instead of wireless communication (or other than wireless communication), the ED may also communicate with a service provider or exchange (not shown) via a wired communication channel and with the Internet 150. PSTN 140 may include a circuit-switched telephone network for providing plain old telephone service (POTS). The Internet 150 may include a network of computers and subnets (intranets) or both, incorporating protocols such as Internet Protocol (IP), Transmission Control Protocol (TCP), and User Datagram Protocol (UDP). EDs 110a to 110c may be multimode devices capable of operating according to multiple wireless access technologies and include multiple transceivers required to support multiple wireless access technologies.

[0068] Figure 2The diagram also shows RIS 182 located within the service area of ​​base station 170b. A first signal 185a between base station 170b and RIS 182 is shown, as well as a second signal 185b between RIS 182 and ED 110b, thus illustrating how RIS 182 is located within the uplink or downlink channel between base station 170b and ED 110b. A third signal 185c between ED 110c and RIS 182 is also shown, and a fourth signal 185d between RIS 182 and ED 110b is shown, thus illustrating how RIS 182 is located within the SL channel between ED 110c and ED 110b.

[0069] Although Figure 2 Only one RIS 182 is shown in the diagram, but it should be understood that any number of RISes can be included in the network.

[0070] Figure 3A and Figure 3B Exemplary apparatuses are shown that can implement the methods and guidance provided by this invention. Specifically, Figure 3A An example ED 110 is shown. Figure 3B An exemplary base station 170 is shown. These components can be used in system 100 or any other suitable system.

[0071] like Figure 3A As shown, ED 110 includes at least one processing unit 200. The processing unit 200 implements various processing operations of ED 110. For example, the processing unit 200 may perform signal encoding, data processing, power control, input / output processing, or any other function that enables ED 110 to operate within communication system 100. The processing unit 200 may also be used to implement some or all of the functions and / or embodiments described in detail herein. Each processing unit 200 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 200 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0072] ED 110 also includes at least one transceiver 202. Transceiver 202 is used to modulate data or other content for transmission by at least one antenna or network interface controller (NIC) 204. Transceiver 202 is also used to demodulate data or other content received through at least one antenna 204. Each transceiver 202 includes any suitable structure for generating signals for wireless or wired transmission and / or for processing signals received wirelessly or wiredly. Each antenna 204 includes any suitable structure for transmitting and / or receiving wireless or wired signals. One or more transceivers 202 may be used in ED 110. One or more antennas 204 may be used in ED 110. Although transceiver 202 is shown as a single functional unit, it can also be implemented using at least one transmitter and at least one separate receiver.

[0073] ED 110 also includes one or more input / output devices 206 or interfaces (e.g., a wired interface to the Internet 150). Input / output devices 206 support interaction with users or other devices on the network. Each input / output device 206 includes any suitable structure for providing or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touchscreen, including network interface communication.

[0074] Furthermore, ED 110 includes at least one memory 208. Memory 208 stores instructions and data used, generated, or collected by ED 110. For example, memory 208 may store software instructions or modules for implementing some or all of the functions and / or embodiments described herein, and executed by one or more processing units 200. Each memory 208 includes any suitable one or more volatile and / or non-volatile storage and retrieval devices. Any suitable type of memory can be used, such as random access memory (RAM), read-only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, etc.

[0075] like Figure 3BAs shown, base station 170 includes at least one processing unit 250, at least one transmitter 252, at least one receiver 254, one or more antennas 256, at least one memory 258, and one or more input / output devices or interfaces 266. Transmitters 252 and receivers 254 may be replaced by transceivers (not shown). Scheduler 253 may be coupled to processing unit 250. Scheduler 253 may be included within base station 170 or may operate separately from base station 170. Processing unit 250 implements various processing operations of base station 170, such as signal encoding, data processing, power control, input / output processing, or any other functions. Processing unit 250 may also be used to implement some or all of the functions and / or embodiments detailed above. Each processing unit 250 includes any suitable processing or computing device for performing one or more operations. For example, each processing unit 250 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0076] Each transmitter 252 includes any suitable structure for generating signals for wireless or wired transmission to one or more EDs or other devices. Each receiver 254 includes any suitable structure for processing signals wirelessly or wiredly received from one or more EDs or other devices. Although shown as separate components, at least one transmitter 252 and at least one receiver 254 may be combined into a transceiver. Each antenna 256 includes any suitable structure for transmitting and / or receiving wireless or wired signals. Although a shared antenna 256 is shown herein coupled to transmitter 252 and receiver 254, one or more antennas 256 may be coupled to one or more transmitters 252, and one or more individual antennas 256 may be coupled to one or more receivers 254. Each memory 258 includes any suitable one or more volatile and / or non-volatile storage and retrieval devices, such as those described above in conjunction with ED 110. Memory 258 stores instructions and data used, generated, or collected by base station 170. For example, memory 258 may store software instructions or modules for implementing some or all of the functions and / or embodiments described above, and be executed by one or more processing units 250.

[0077] Each input / output device 266 supports interaction with users or other devices in the network. Each input / output device 266 includes any suitable structure for providing or receiving information from users, including network interface communication.

[0078] Figure 3C An exemplary RIS device is shown that can implement the methods and guidance provided by this invention. In particular, Figure 3CAn exemplary RIS 182 is shown. These components can be used in System 100 or any other suitable system.

[0079] like Figure 3C As shown, RIS 182 includes: a controller 285 including at least one processing unit 280, an interface 290, and a set of configurable elements 275.

[0080] Processing unit 280 implements various processing operations of RIS 182, such as receiving configuration signals through interface 290 and providing the signals to controller 285. For example, processing unit 280 may include a microprocessor, microcontroller, digital signal processor, field-programmable gate array, or application-specific integrated circuit.

[0081] While this is a specific example of RIS, it should be understood that RIS can take different forms and differ from others. Figure 3C The different implementations shown are as follows. The RIS 182 ultimately requires a configurable combination of components, which can be configured for operation as described in this document.

[0082] Although Figure 3C An interface for receiving configuration information from the network is shown, but in an embodiment, when an antenna or sensor is to be connected to the RIS, it can be considered a separate element from the RIS.

[0083] Further details regarding UE 110 and base station 170 are known to those skilled in the art. Therefore, for clarity, these details are omitted herein.

[0084] This section describes the practical implementation of RIS and some methods for channel estimation and rate maximization using RIS.

[0085] As mentioned above, the phase removal caused by the configurable elements of the RIS depends not only on the bias voltage used to control the RIS, but also on the frequency of the incident wave. The following description explains how this phenomenon affects the reflected signal from the RIS between the transmitter and receiver.

[0086] Depending on the type of material used in the RIS, a phase shift range at a first frequency can be obtained within a specific bias voltage range, but a similar phase shift range at a second frequency may require different bias voltage ranges with different start and end voltages. In a certain type of RIS material, at a frequency of 121.5 GHz, almost the entire phase shift range is obtained within a voltage range between 1.6 V and 2.7 V, while other applied voltages result in a nearly constant phase shift. However, at a frequency of 126 GHz, almost the entire phase shift range is obtained within a voltage range between 1 V and 1.6 V. Therefore, for this type of RIS, different and separate bias voltage ranges need to be applied at different frequencies to obtain the desired phase shift. This is more pronounced when the difference between frequencies is large.

[0087] refer to Figure 1 According to some embodiments of the invention, a planar array (RIS) 4 of configurable elements located between source 2 and destination 6 can be operated such that different portions of the planar array are configured with different bias voltages, such that each portion is configured to redirect a specific frequency in a specific direction while having a marginal effect on signals of other frequencies. In a particular example, when AoA = 0 degrees and AoD is unknown, the RIS can be divided into multiple portions (e.g., 2), where different assumed AoDs are assumed for each portion. For ease of discussion, for a frequency of 120 GHz, AoD is assumed to be 25 degrees, and for a frequency of 128 GHz, AoD is assumed to be 40 degrees. Figure 4A This is illustrated in the diagram, where the AoA is the same for signals arriving at RIS 404 from base station 402. RIS 404 is shown to be divided into two parts, 404a and 404b. Part 404a is configured with a bias voltage to assume AoD redirection f1 = 120 GHz at 25 degrees, and part 404b is configured with a bias voltage to assume AoD redirection f2 = 128 GHz at 40 degrees. When base station 402 transmits signals of different frequencies (f1 and f2), or a wideband signal comprising both frequencies, the normalized RIS gain is maximized at an assumed AoD close to the true AoD, as shown below. Figure 4B As shown.

[0088] Figure 4BThis simulation is used to determine the true AoD of signals transmitted at 120 GHz and 128 GHz at base station 402 at the RIS, where the AoA is 0 degrees for signals at these frequencies, and the AoD is assumed to be 25 degrees and 40 degrees respectively. In this simulation, the length of RIS 404 is 20 RIS elements, divided such that 10 elements of total length are used to redirect the 120 GHz signal and 10 elements of total length are used to redirect the 128 GHz signal. When transmitting a wideband signal, the maximum gain is associated with a specific frequency or frequency subband. The normalized RIS gain can be determined by dividing the true RIS gain by the gain and signal-to-noise ratio (SNR) of each RIS element, where SNR = G T G R E T / N0, where G T It is the transmitter (base station 402) gain, G R It is the receiver (UE 406) gain, E T N is the energy transmission, and N0 is the noise variance.

[0089] If the first and second frequencies are relatively close (e.g., 124 GHz and 125 GHz), applying the same set of bias voltages to both parts of the RIS will not cause significant phase shifts in the signal at these frequencies. However, the same set of bias voltages will have significantly different effects at different frequencies within the frequency range, resulting in different group delays at specific frequencies within the range. Group delay is considered to be the derivative of the phase shift with respect to frequency. Therefore, broadband signals reflected by the RIS will experience multipath fading.

[0090] To illustrate the impact of latency on different groups, consider deployments in... Figure 1 The RIS design is used in the basic channel. In a specific example, the transmission has an AoA of 50 degrees at the RIS, while the AoD is assumed to be 65 degrees. Furthermore, the RIS is configured to reflect or redirect incident signals at a frequency of 100 GHz. Figure 5A A graphical representation is shown, generated from a simulation used to determine the actual AoD (Average Area of ​​Degree) of broadband signals transmitted at base station 502 at frequencies of 100 GHz, 95 GHz, and 85 GHz at the RIS. For signals at these frequencies, AoA is 50 degrees, and AoD is assumed to be 65 degrees, 61 degrees, and 57 degrees, respectively. In this simulation, the RIS504 has a length of 10 elements. From... Figure 5AIt can be seen that for the frequency components at 100 GHz, the normalized RIS gain is maximized when the actual AoD is close to the assumed AoD. However, for other frequency components at 95 GHz and 85 GHz, the maximum gain is achieved when the actual AoD is 61 degrees and 57 degrees, respectively, which deviates from the assumed AoD (i.e., 65 degrees).

[0091] Figure 5B The channel between base station 502, RIS 504, and UE 506 is shown, and how the three frequency components of the broadband signal, 100GHz 510, 95GHz 511, and 85GHz 512, have the same AoA, but with different characteristics compared to... Figure 5A and Figure 5C The figure shows different AoDs based on the assumption of AoD. The UE's beam scanning beam 515 is also shown in the figure.

[0092] Figure 5C Another simulation is shown at the same three frequencies of 100 GHz, 95 GHz, and 85 GHz, demonstrating that the deviation decreases as AoA approaches AoD. Figure 5C In specific examples, AoA has already... Figure 5A The degree in the range increases from 50 to 60, while the AoD remains at 65 degrees.

[0093] The first two examples illustrate the effect of the prism-like effect on the RIS reflection of incident signals at different frequencies. Now, examples of how this prism-like effect can be utilized in channel estimation and data transmission will be described.

[0094] As described above, the RIS reflects signals of different frequencies (or different frequency components of a broadband signal) in different directions. Therefore, when performing channel estimation (which may include AoD estimation of signals redirected from a planar array of configurable elements), some embodiments of the present invention enable the planar array of configurable elements to simultaneously estimate multiple AoDs by appropriately selecting the frequency of the transmitted signal.

[0095] Some embodiments of the invention also enable a planar array of configurable elements to serve multiple UEs, each using a narrowband frequency, wherein the planar array of configurable elements can be configured with disjoint sets of voltages for different frequencies. This can reduce interference between UEs.

[0096] As described above, for broadband communication covering a certain frequency range, the signal reflected by the RIS may experience multipath fading due to the different group delays at different frequencies in broadband communication. Some embodiments of the present invention describe how to compensate for this multipath fading. Various embodiments providing compensation at the transmitter, receiver, or RIS are described.

[0097] It should be noted that the terms "narrow bandwidth," "narrow band," "narrow band frequency," and "narrow frequency band" are used interchangeably to refer to the same type of signal. Similarly, the terms "wide bandwidth," "wide frequency band," and "wide frequency band" are used interchangeably to refer to the same type of signal.

[0098] For a specific RIS implementation as described above, if the lower and upper ends of the signal band experience almost the same phase shift for each RIS configurable element's specific configuration when the reference or data signal incident on the RIS is redirected by the RIS, then the signal can be considered to have a narrow bandwidth. Otherwise, the signal is considered to have a wide bandwidth.

[0099] A RIS (Reference Signal Controller) comprising multiple configurable elements can redirect transmitted signals in multiple directions by appropriately selecting the frequency of the transmitted signal. The selection of the frequency components to be used in channel estimation can be done at the base station, or more generally elsewhere within the network, by sending commands to the RIS's controller. For example, the base station or network can provide the RIS controller with information relating to: the frequency of the reference signal available for channel estimation; the AoA (Aspect-Oriented Area) from the base station transmitting the signal to the RIS based on location information between the base station and the RIS; the expected AoD (Aspect-Oriented Distance) from the RIS; or the difference between these two values. This allows the RIS controller to determine how to configure some or all of the RIS's elements.

[0100] While the following embodiments describe schemes in the context of downlink channel estimation (i.e., in the direction from the base station via the RIS to the UE), it should be understood that these schemes can be extended to channel estimation in the uplink direction (i.e., from the UE via the RIS to the base station). These schemes can be further extended to sidelink communication, i.e., communication between two UEs via the RIS with the assistance of the network.

[0101] The RIS can be configured to be virtually divided into multiple parts, such that each part reflects or redirects signals of a specific frequency in different directions. In some embodiments, the beams of the reflected signals substantially do not overlap. "Substantially non-overlapping" means that the beams generally do not overlap; however, some overlap may inevitably occur. For example, in... Figure 4B In the diagram, the reflected beams slightly overlap, as the beams shown are all contained within the range of 30 to 35 degrees.

[0102] In cases where beams do not overlap substantially, the base station transmits beamguided beams to a Reference Signal System (RIS) comprising multiple reference signals, each with a narrow bandwidth. An example of a type of reference signal that can be used is a Channel State Information Reference Signal (CSI-RS). Reference signals partially reflected by RIS components configured with different bias voltages are redirected in different directions.

[0103] The base station can also configure the UE by providing it with an identifier of a frequency that will be transmitted by the base station and redirected by the RIS via a radio resource control (RRC) configuration message. During beam scanning, the UE measures the signal at the identified frequency. Examples of measurement types the UE can perform include measuring reference signal received power (RSRP), reference signal strength indicator (RSSI), reference signal received quality (RSRQ), or signal-to-noise ratio (SNR). The UE then feeds back an identifier corresponding to the reference signal with the strongest measurement. It should be noted that the UE can also feed back multiple identifiers corresponding to multiple reference signals with good measurements (e.g., equal to or greater than a threshold for measurements such as RSRP, RSSI, RSRQ, or SNR required to meet the UE's service requirements, such as data rate). For example, if the reference signal is a CSI-RS, the identifier could be one or more CSI-RS indices.

[0104] Based on one or more identified indices, the base station is able to estimate the AoD from RIS to UE for a specific frequency of a signal that provides the strongest signal strength at the UE or a signal that meets a threshold.

[0105] Once the base station performs channel estimation and determines the optimal AoD for transmitting data to the UE, it can configure the RIS (Reflection Array) to transmit data to the UE. One option is that the entire RIS can be configured to reflect at the desired AoD at a given transmission frequency to increase gain in that direction. This also allows more data to be transmitted over multiple narrowband signals, as is often the case when using carrier aggregation. Alternatively, frequency-selective scheduling can be combined with beamforming to maximize the rate experienced at the receiver. Another option is that a sufficient portion of the RIS (relative to the entire RIS) is configured for reflection such that the received signal at the receiver (e.g., the UE) meets specific requirements, such as a data rate threshold. In this option, the remaining portion of the RIS can be used for other purposes, such as serving one or more other UEs.

[0106] It should be noted that if the UE only feeds back a measurement of a single reference signal, the UE already knows on which beam (e.g., the AoA at the UE) it will receive transmitted data from the base station. However, if the UE feeds back measurements of multiple reference signals, the base station, after selecting one or more feedback measurements to estimate the channel, may need to send back an index of the selected reference signal used for estimation so that the UE knows on which beam (one or more AoA at the UE) it will receive transmitted data from the BS.

[0107] While the examples above include a discussion of channel estimation and data transmission, it should be understood that these two aspects can be used together or separately. Some embodiments utilize only a prism-like effect for channel estimation while avoiding data transmission. Other embodiments may perform channel estimation using other methods but use the prism effect for the data transmission step.

[0108] The number of directions the RIS can reflect can depend on the number of frequencies that can be independently configured to reflect in a specific direction while having a minor impact on the reflection direction of other frequencies related to the non-intersecting range of the applied bias voltage, as described above. If more directions are needed, the base station can perform another transmission of the reference signal at different times using a different configuration of the planar array to reflect it in the new direction. This process is called multi-beam scanning.

[0109] The base station can also instruct the RIS to deploy layered beamforming, meaning the RIS reflects the base station signal into multiple directions of a wide beam. Then, from the selected wide beam direction, the base station further configures the RIS to reflect multiple narrow beams in directions associated with the wide beam.

[0110] The above example describing downlink (DL) transmission can be applied to uplink (UL) transmission as follows. In the UL, given the locations of the RIS and the base station, and both the RIS and the base station are connected to the network, the AoD from the RIS to the base station is known. The base station can configure the UE via RRC signaling to transmit different sounding reference signals (SRS) at different frequencies on each beam or through multiple beams. Furthermore, the base station can configure the RIS such that each RIS portion reflects an incident signal (given AoD) of a specific frequency back to the base station, assuming the AoA differs from the AoA of signals at other frequencies. Then, while beam scanning, the UE transmits SRSs, which are reflected differently (when arriving at the RIS) taking into account their different frequencies. The base station then performs some measurements on the received SRSs. Based on these measurements, the base station estimates the AoA at the RIS. Afterward, the base station configures the RIS to perform appropriate reflections (e.g., maximizing gain at the base station), feeds back one or more indices of the SRS with good measurements, and informs the UE of the transmission scheme (e.g., multi-narrowband transmission at different frequencies).

[0111] Several options exist to adapt the above examples to side-link (SL) communication. Without loss of generality, SL can be viewed as a UE (UE1) wishing to send information to another UE (UE2) with the assistance of RIS. Some exemplary embodiments are given below, but it should be understood that other similar embodiments may also exist.

[0112] Example 1: The network or base station knows the AoA of the signal from the base station to the RIS and the AoD from the RIS to the base station. Then, the AoD from the RIS to UE2 can be estimated as in the DL explained in the example above, while the AoA from UE1 to the RIS can be estimated as in the UL transmission explained above. The base station then configures the RIS to correctly reflect signals from UE1 to UE2 and informs UE1 and UE2 of the transmission scheme (e.g., multi-narrowband transmission at different frequencies).

[0113] Example 2: Similar to Example 1 above, the AoD from RIS to UE2 can be estimated as in the DL explained in the previous example. Then, the AoA from UE1 to RIS can be estimated as in UL transmission, except that the base station configures RIS to reflect the reference signal from UE1 to UE2. UE2 then performs a measurement and feeds the measurement back to the base station or both the base station and UE1. The base station then determines the AoA at RIS and configures RIS to perform reflection to increase the signal gain from UE1 to UE2. The base station also informs UE1 of one or more reference signal indices and transmission schemes. The base station also informs UE2 of the transmission scheme through which the two UEs can communicate.

[0114] Example 3: In short, this is another direction of Example 2. Similar to Example 1, the AoA from UE1 to RIS can be estimated as explained in the UL transmission above. Then, the AoD from RIS to UE2 can be estimated as in the DL transmission, except that the base station configures RIS to reflect the reference signal from UE1 to UE2. UE2 then performs a measurement and feeds that measurement back to the base station or both the base station and UE1. The base station then determines the AoD at RIS and configures RIS to perform appropriate reflections to increase the signal gain from UE1 to UE2. The base station also informs UE1 of one or more reference signal indices with good measurements. The base station also informs both UEs of a transmission scheme through which the two UEs can communicate.

[0115] Example 4: This example describes how to estimate the AoA to the RIS and the AoD from the RIS by transmitting reference signals between UEs. For example, for a hypothetical AoA from UE1 to the RIS and multiple hypothetical AoDs to UE2, the network or base station configures the RIS to reflect incident signals of different frequencies in different directions and configures UE1 to transmit reference signals of different frequencies. This process is repeated for different hypothetical AoA and AoD. It should be noted that both UEs perform beam scanning. UE2 then feeds back the measurement results to the base station or to both the base station and UE1. Based on the measurements, the base station determines the AoA and AoD. The base station also notifies both UEs of one or more indices of the reference signals with good measurements. The base station also notifies both UEs of a transmission scheme through which the two UEs can communicate. This method can also be performed in different ways, for example, considering one hypothetical AoD and multiple hypothetical AoA; or multiple hypothetical AoA and multiple hypothetical AoD.

[0116] In some embodiments, two or more beams of the signal reflected or redirected by the RIS overlap each other. For example... Figure 5A This illustrates how reflected beams essentially overlap between 50 and 75 degrees. The channel approach used for overlapping reflected beams differs from that used for non-overlapping beams.

[0117] In this method, the RIS is configured by a base station or network device to control multiple parts using different bias voltages, such that each part of the RIS reflects signals of a specific frequency component in different directions.

[0118] The base station then directs a transmission beam to the RIS, which includes several narrow-bandwidth reference signals that will be reflected by the RIS in different directions. In some embodiments, the reference signals may be CSI-RS.

[0119] The base station can also configure the UE by providing the UE with an identifier of the frequency to be transmitted by the base station and redirected by RIS via an RRC configuration message. While performing beam scanning, the UE measures the received signal at the frequency identified by the base station, including RSRP, RSSI, RSRQ, and / or SNR.

[0120] The UE provides identifiers for the two or more strongest reference signals. In some embodiments, the UE may also provide the corresponding RSRP ratio of the two strongest measurements.

[0121] Figure 6A A simulation of the normalized gain of a channel with a linear array between a transmitter and receiver is shown, where the linear array reflects beams comprising four different frequency elements in different assumed directions, based on different configurations of portions of the array. However, the reflected beams overlap, meaning each beam covers a portion of the phase range of one or more adjacent beams. The linear RIS array described here is a single row of N configurable elements, not a two-dimensional array of N×M configurable elements. Figure 1 As shown. The linear array in the simulation is divided into four parts, such that it is similar to... Figure 5A The method reflects each of the four frequency components in different directions. This simulation represents the AoD of the frequencies after being redirected by the planar array.

[0122] Based on the frequency and RSRP ratio of the reference signal identifier provided by the UE to the base station, the base station can estimate the AoD from the linear array to the UE. For a UE with a specific position relative to the linear array, an appropriate AoD can be determined based on the measured power of each given frequency component, thus ensuring good received signal power reaching the UE. For example, considering factors such as... Figure 6AThe diagram shows the corresponding frequency components with corresponding AoD. If the UE wants to measure the maximum gain of the frequency component 610 with an AoD of 30 degrees, and other frequency components have decreasing gains, then an angle of 30 degrees provides the best signal to the UE. If the normalized gains of the reflected signals at 30 degrees 610 and 40 degrees 620 are approximately equal, and the frequency components have decreasing gains, then an angle between 30 degrees and 40 degrees provides the best signal to the UE. Since the signal gains at 30 degrees and 40 degrees are approximately the same, this means that an AoD of 35 degrees provides the best signal to the UE.

[0123] If the base station subsequently needs to utilize a prism-like effect for data transmission, it configures all portions of the planar array to reflect data with the desired AoD at a given transmission frequency to increase gain in that direction. This also allows more data to be transmitted over multiple narrowband signals, as is often the case when using carrier aggregation. Alternatively, frequency-selective scheduling can be combined with beamforming to maximize the rate experienced at the receiver. Sufficient RIS portions can also be configured for reflection to the UE while still meeting its service requirements (e.g., transmission rate). Using this option, the remaining RIS portions can be used for other purposes (e.g., serving one or more other UEs).

[0124] Figure 6B This is a simulated graphical representation showing the mean square error (MSE) performance of the proposed AoD estimate plotted relative to the tilt angle at the linear RIS array. The tilt angle is π / 2–θr, where θr is the actual or true AoD. The element size is equal to 0.25λ. 2 Where λ is the wavelength, L / λ = 20, and L is the length of the linear RIS array. The wavelength is c / f, where c is the speed of light and f is the frequency within the operating range of the RIS. The linear array is divided into K parts, and the total number of elements in the linear array is N. After obtaining... Figure 6A In the simulation, K=4 and N=40, the transmitter gain G T and receiver gain G R Set to equal 0dB. Furthermore, in the simulation, P... t / (4π(D1D2) 2 ) = 0dB, P t D1 is the transmit power, D2 is the distance between the base station and the RIS, and D2 is the distance between the RIS and the UE. For a panel RIS, there are N×M configurable elements, where M=N=40, with a known elevation angle AoD (considering the transmitter (base station antenna), receiver (held by the user), and the RIS height being known, the elevation angle varies within a small range) and the same length L, MSE can be improved by up to 32dB (i.e., 10*log(40)). 2It should be understood that the gain will vary based on the size of the RIS array. Additionally, it should be noted that even if the elevation angle is unknown, it can be estimated in a similar manner to the azimuth angle (e.g., by vertically dividing the RIS into distinct sections and then following a similar approach described for the azimuth angle). These methods can also be extended to other two-dimensional or three-dimensional configurations of the RIS configurable elements (e.g., circular or hexagonal configurations).

[0125] The above-described embodiments involving overlapping beams can be extended to UL and SL transmissions in a manner similar to that described above-described embodiments involving substantially non-overlapping beams.

[0126] These two embodiments describe the transmission of relatively narrowband signals used for estimating, and, when necessary, when utilizing the prism-like effect of the RIS. The narrowband signals are frequency-separated so that they are reflected independently by the planar array. However, another approach is to utilize the RIS to reflect or redirect wider bandwidth signals, which will be explained below. In some embodiments, this may be particularly relevant to wider bandwidth signals at higher frequencies.

[0127] Base station or network equipment can provide configuration information to configure a planar array to reflect incident broadband signals based on specific frequencies in the broadband signal.

[0128] The base station then directs the transmission beam onto a planar array that includes a broadband reference signal. In some embodiments, the broadband reference signal may be a broadband CSI-RS. Specific frequency components in the broadband reference signal are reflected in a specific direction, while other frequency components may deviate from that specific direction. This is related to... Figure 5A and Figure 5C In the examples, incident narrowband reference signals of different frequencies are reflected in similar ways in different directions.

[0129] For example, a base station transmits a broadband pilot signal (also called a reference signal) reflected by a RIS at an assumed AoD (e.g., 30 degrees). Due to a prism-like effect or RIS configuration, the reflected beam covers a range of 15 to 45 degrees for different frequency components in the broadband pilot signal. Then, at another transmission time, the base station can transmit another pilot signal reflected by the RIS at a different assumed AoD (e.g., 60 degrees). Due to a prism-like effect or RIS configuration, the reflected beam covers a range of 45 to 75 degrees for all frequencies.

[0130] The base station can also configure the UE by providing information about a broadband reference signal to be transmitted by the base station and redirected by the planar array via an RRC configuration message. While performing beam scanning, the UE performs measurements to determine the frequency response of the received broadband signal, which includes the amplitude, phase, or magnitude and phase relative to the frequency.

[0131] Based on channel measurements performed by the UE, the UE feeds back identification and frequency response information for one or more good (e.g., strongest or meeting a specific RSRP or SNR threshold) reference signal components of the broadband reference signal. For example, when the reference signal is a broadband CSI-RS, this could be an identifier of the CSI-RS index that identifies one or more frequency components in the broadband signal that have good signal characteristics (e.g., strongest or meeting a specific RSRP or SNR threshold).

[0132] Based on the frequency response information and the strongest reference signal component of the broadband reference signal, the base station can estimate the AoD from the planar array to the UE. In some embodiments, the base station can also estimate the impact of multipath fading caused by the prism-like effect of the aforementioned planar array on the channel.

[0133] If the base station subsequently needs to utilize a prism-like effect for data transmission, multipath fading can be compensated for in a variety of different ways.

[0134] In some embodiments, multipath fading compensation can be achieved by the base station using OFDM transmission with a subcarrier spacing that depends on the measured frequency response.

[0135] In some embodiments, multipath fading compensation can be achieved by configuring a planar array at the base station to reduce deviation from the main desired direction corresponding to the estimated AoD. This can be accomplished by performing one or more of the following:

[0136] (a) Use a wide beam to reflect the data signal at RIS, the wide beam being larger than the deviation caused by the prism-like effect, to avoid data loss;

[0137] (b) Divide the RIS surface into smaller portions, each portion redirecting a subset of the broadband data signals incident on the RIS; and

[0138] (c) Continuously optimize the beam pointing continuously at the receiver's RIS surface for different frequencies. For example, the leftmost portion of the RIS reflects the lowest frequency beam in the frequency band, and as the beam moves to the right of the RIS, the optimized frequency gradually increases until the rightmost portion of the RIS reflects the highest frequency beam in the frequency band. This may involve configuring the RIS such that different sets of one or more configurable elements of the RIS redirect the broadband beam incident on the RIS from one end of the RIS to the other end of the RIS in different directions.

[0139] In some embodiments, multipath fading compensation can be achieved by the base station instructing the UE to perform an equalization method (e.g., rake the receiver) to compensate for multipath fading caused by the planar array.

[0140] The above-described embodiments involving broadband signals with multiple frequency components can be extended to UL and SL transmissions in a manner similar to the other embodiments described above.

[0141] In the described embodiments, it should be understood that signaling and measurements sent between network nodes may take other forms than those explicitly described; for example, a measurement may be a function of measurement information.

[0142] The following details some of the potential benefits of the above embodiments.

[0143] In the above embodiments, the RIS intentionally reflects or redirects in multiple directions (e.g., in the case of overlapping or non-overlapping beams of a narrow-bandwidth reference signal), or due to the orientation of certain frequency elements deviating from the orientation of specific frequency elements of the reflected or redirected broadband reference signal. Simultaneous reflection of multiple frequency elements helps to speed up the scanning process. Furthermore, for certain types of materials used in planar arrays (e.g., liquid crystals), the response time for reconfiguring the orientation of elements to reflect in another direction can be on the order of microseconds or milliseconds. The reduced overhead used as part of simultaneous reflection allows sufficient time to reconfigure the planar array for these types of materials. For example, if different frequencies are transmitted sequentially at different time intervals, requiring the RIS to be reconfigured for each frequency, the RIS is configured for a first direction. However, it is necessary to wait for a duration equal to the RIS response time to ensure that the configurable elements of the RIS have been established to the correct configuration. Once the first frequency is transmitted, the RIS is reconfigured so that the RIS can reflect a second frequency in a second direction. This process is repeated eight times. Therefore, to cover all 10 frequency directions, the waiting time is equal to 10 times the RIS response time. However, since up to five frequencies are reflected simultaneously in five directions, the additional waiting time to cover 10 directions is two response times: the first time corresponds to the first group of five frequencies, and the second time corresponds to the second group of five frequencies.

[0144] For embodiments using broadband transmission, the base station can notify the UE of the presence of RIS in the channel path. This is helpful because the planar array makes the channel appear as a multipath fading channel, although at high frequencies the channel is generally flat with less scattering.

[0145] As part of channel estimation and data transmission functions, some signaling functions are used between the network and the plane array, in some cases between network devices and the plane array, and in some cases between the base station and the plane array. Some signaling functions are also used between the base station and the UE. Some examples of new signaling, which will be described in further detail below, include mechanisms by which the base station notifies the UE that the RIS is being used in the channel between the base station and the UE, mechanisms by which the UE feeds back frequency response information of the channel to help the base station determine the AoD at the RIS, and signaling that enables multipath fading compensation.

[0146] Now we will use Figure 7 Explain some of the signaling used for downlink channel estimation and data transmission. Figure 7 A flowchart 700 illustrating downlink channel estimation and data transmission involving base station 702, planar array (labeled RIS) 704, and UE 706 is shown. These are elements that are part of the network, but other components in the network can also perform functions that control how the network operates. For example, the network can provide configuration information to the planar array directly via a wired or wireless connection, or the network can provide configuration information to the planar array through the base station. It should be understood that, although Figure 7 This is for downlink channel estimation and data transmission, but similar principles can be applied to implement uplink channel estimation and data transmission.

[0147] The network can inform base station 702 of the type of RIS being used in the channel. For example, lumped elements such as PIN diodes, transformers, transistors, or MEMS at low frequencies, liquid crystals at high frequencies, and graphene at even higher frequencies. The type can also refer to specific characteristics, such as the relationship between bias voltage, phase shift, and frequency. In some embodiments, the type can be... Figure 7 The event shown is previously identified by the base station. In some embodiments, this information may be part of the configuration information sent to the base station by the RIS in step 710.

[0148] Base station 702 sends (710) configuration information to RIS 704. The configuration information informs RIS 704 that base station 702 will send a reference signal (CSI-RS in this example) in the direction that RIS 704 will redirect to UE 706. This configuration information helps RIS 704 generate a hologram, which is control information driving the configurable elements of RIS 704. This hologram can be a set of bias voltages for the configurable elements of RIS 704. The configuration information includes one or more of the following:

[0149] (a) The carrier frequency of the reference signal;

[0150] (b) The difference in phase shift between adjacent planar array elements;

[0151] (c) One or more assumed AoDs;

[0152] (d)AoA, especially when the planar array is sensitive to the angle of incidence, such as in some types of liquid crystal RIS, AoA may be required;

[0153] (e) the beamwidth of the reflected signal; and

[0154] (f) Identification of the portion of the planar array configured to reflect the corresponding reference signal.

[0155] Although the base station 702 is shown sending configuration information (as described above), the configuration information can be provided to the RIS 704 by network devices other than the base station via wired and / or wireless connections. Furthermore, as described above, the network (when connected to the RIS) can inform the base station 702 about the RIS's configuration, as suggested by the bidirectional arrows in 710.

[0156] Base station 702 sends (715) configuration information to UE 706 regarding reference signals and carrier frequencies of multiple narrow or wide signals. In some embodiments, the configuration information may also include the identifier of RIS 704 in the path of the communication channel, because the measurement and feedback process for channel estimation differs from the measurement and feedback process if RIS 704 is not in the path.

[0157] Base station 702 transmits (720) a reference signal redirected by RIS 704 to UE 706. Although in Figure 7 The signal flow diagram shows three separate transmissions, but it should be understood that the reference signal transmissions can be simultaneous or at separate times. Furthermore, although... Figure 7 The image shows three signals being sent, but this is just an example; there may be more or fewer than three signals being sent.

[0158] UE 706 measures (725) the redirected reference signal, and then UE 706 sends (730) feedback to base station 702 and / or toward RIS 704 so that RIS 704 will reflect the feedback back to the base station. For narrowband reference signals, UE 706 measures the reference signal and feeds the information back to base station 702. For wideband reference signals, UE 706 measures the frequency response and feeds that frequency response back to base station 702. In the scenario of wideband reference signals, when using RIS 704, the channel between base station 702 and UE 706 will behave similarly to a multipath fading channel, which differs from a conventional THz channel that primarily consists of a few distinguishable paths (e.g., a line-of-sight (LOS) path and one or two other paths). UE 706 may measure the RSRP or RSSI of two or more reference signals, or the ratio of two RSRPs or RSSIs. UE 706 sends (730) feedback to base station 702 through various methods, including but not limited to the following:

[0159] A previously known direct link with acceptable quality exists between UE 706 and base station 702;

[0160] The RIS 704's reflection link is known to have acceptable quality from previous "connections";

[0161] Direct links to base station 702 in different frequency bands (e.g., microwave bands);

[0162] Different radio access technology (RAT) mechanisms, such as Bluetooth or Zigbee.

[0163] Base station 702 receives information transmitted from UE 706 and performs processing 735 to estimate the channel. This may include base station 702 determining the AoD of a reference signal at RIS based on the received information. This may include base station 702 determining, based on signal measurements received from UE 706, a portion of a configurable element that redirects a reference signal at a given frequency in a given direction. Base station 702 may then determine, based on the frequency at which data will be transmitted to RIS 704 to obtain the desired AoD from RIS 704. The channel estimation, often referred to as channel information, may include, but is not limited to, the desired AoD from RIS for data transmissions sent by the base station and redirected by RIS for a specific carrier frequency.

[0164] Then, base station 702 sends (740) configuration information to RIS 704 to configure RIS 704 such that data sent by base station 702 to UE 706 will be redirected by RIS 704 in an appropriate manner. The configuration information sent to RIS 704 can also help compensate for multipath effects caused by the prism-like effect of RIS 704. For example, in some embodiments, RIS 704 can be configured to reflect broadband signals to UE 706 with a small deviation from the desired AoD. RIS 704 generates a hologram including bias control information based on the configuration information received from base station 702.

[0165] Base station 702 also sends (745) an identifier of the channel that RIS 704 will use for downlink data communication, which notifies UE 706 to perform some kind of channel equalization to compensate for multipath fading of the channel caused by the prism-like effect of RIS 704. This allows UE 706 to distinguish between equalization methods for transmissions received directly from the base station and transmissions that have been redirected from RIS 704.

[0166] Base station 702 and UE 706 transmit and receive (750) data on the channel via RIS 704. Base station 702 may use specific waveforms, such as orthogonal frequency division multiplexing (OFDM) transmission with specific subcarrier spacing, to mitigate multipath fading in the channel.

[0167] Now we will use Figure 8 Additional examples of signaling used for uplink channel estimation and data transmission are provided. Figure 8 A flowchart 800 illustrating downlink channel estimation and data transmission involving base station 802, planar array (labeled RIS) 804, and UE 806 is shown. These are elements that are part of the network, but other components in the network can also perform functions that control how the network operates. For example, the network can provide configuration information to the planar array directly via a wired or wireless connection, or the network can provide configuration information to the planar array through the base station. It should be understood that, although Figure 8 This is for downlink channel estimation and data transmission, but similar principles can be applied to implement uplink channel estimation and data transmission.

[0168] The network can inform base station 802 of the type of RIS being used in the channel. For example, lumped elements such as PIN diodes, transformers, transistors, or MEMS at low frequencies, liquid crystals at high frequencies, and graphene at even higher frequencies. The type can also refer to specific characteristics, such as the relationship between bias voltage, phase shift, and frequency. In some embodiments, the type can be... Figure 8The event shown is previously identified by the base station. In some embodiments, this information may be part of the configuration information sent to the base station by the RIS in step 810.

[0169] Base station 802 sends configuration information (810) to RIS 804. The configuration information informs RIS 804 that UE 806 will transmit a reference signal (SRS in this example) in the direction that RIS 804 will redirect to RIS 804 of base station 802. This configuration information helps RIS 804 generate a hologram, which is control information driving the configurable elements of RIS 804. This hologram can be a set of bias voltages for the configurable elements of RIS 804. The configuration information includes one or more of the following:

[0170] (a) The carrier frequency of the reference signal;

[0171] (b) The difference in phase shift between adjacent planar array elements;

[0172] (c) One or more hypothetical AoA;

[0173] (d)AoD;

[0174] (e) the beamwidth of the reflected signal; and

[0175] (f) Identification of the portion of the planar array configured to reflect the corresponding reference signal.

[0176] Although the base station 802 is shown sending configuration information (as described above), the configuration information can be provided to the RIS 804 by network devices other than the base station via wired and / or wireless connections. Furthermore, as described above, the network (when connected to the RIS) can inform the base station 802 about the RIS's configuration, as suggested by the bidirectional arrows in 810.

[0177] Base station 802 sends (815) configuration information to UE 806 regarding reference signals and carrier frequencies of multiple narrow or wide signals. In some embodiments, the configuration information may also include the identifier of RIS 804 in the path of the communication channel, because the measurement and feedback process for channel estimation differs from the measurement and feedback process if RIS 804 is not in the path.

[0178] UE 806 transmits (820) a reference signal redirected by RIS 804 to base station 802. Although in Figure 8 The signal flow diagram shows three separate transmissions, but it should be understood that the reference signal transmissions can be simultaneous or at separate times. Furthermore, although... Figure 8 The image shows three signals being sent, but this is just an example; there may be more or fewer than three signals being sent.

[0179] Base station 802 measures the (825) redirected reference signal. For narrowband reference signals, base station 802 measures the reference signal. For wideband reference signals, base station 802 measures the frequency response. In the scenario of wideband reference signals, when using RIS 804, the channel between base station 802 and UE 806 will behave similarly to a multipath fading channel, which differs from a conventional THz channel consisting primarily of a few distinguishable paths (e.g., a Loss path and one or two other paths). Base station 802 can measure the RSRP or RSSI of two or more reference signals, or the ratio of two RSRPs or RSSIs.

[0180] Base station 802 performs processing (830) to estimate the channel by utilizing a prism-like effect. This may include base station 802 determining the AoA of a reference signal at RIS based on received information. This may include base station 802 determining, based on signal measurements, portions of configurable elements that redirect a reference signal at a given frequency in a given direction. Base station 802 may then determine configuration information to be sent to RIS 804 to obtain the desired AoA from UE 806 to RIS 804, based on the frequency to be used to receive data from UE 806 via RIS 804. Processing 830 may also involve determining compensation for the prism-like effect, determining the UE's transmission method, including configuration information that may need to be sent to the UE to implement the transmission method. The channel estimation, often referred to as channel information, may include, but is not limited to, the desired AoA from RIS for data transmission by the UE and redirected by RIS for a specific carrier frequency.

[0181] Base station 802 also sends to UE 806 one or more of the following: SRS measurements performed by base station 802, frequency response, and configuration information used by UE for data transmission. Base station 802 also sends (835) prism-like effect compensation configuration information to compensate for multipath fading of the channel caused by the prism-like effect of RIS 804.

[0182] Then, base station 802 sends (840) configuration information to RIS 804 to configure RIS 804 such that data transmitted from UE 806 to base station 802 will be redirected by RIS 804 in an appropriate manner. The configuration information may include information enabling RIS to generate appropriate holograms for configurable elements of RIS to redirect data transmission in the direction in which the data transmission will reach UE 806, such as, but not limited to, a defined AoA from RIS 804 to UE 802 for data transmission on a specific carrier frequency. The configuration information sent to RIS 804 may also help compensate for multipath effects caused by prism-like effects of RIS 804. For example, in some embodiments, RIS 804 may be configured to reflect broadband signals to base station 802 with a small deviation from the desired AoA. RIS 804 generates a hologram including bias control information based on the configuration information received from base station 802.

[0183] UE 806 and base station 802 transmit and receive (845) data on the channel via RIS 804. UE 806 may use specific waveforms, such as OFDM transmission with specific subcarrier spacing, to mitigate multipath fading in the channel.

[0184] It should be understood that one or more steps of the methods provided in the embodiments herein can be performed by corresponding units or modules. For example, a signal can be transmitted by a transmitting unit or transmitting module. A signal can be received by a receiving unit or receiving module. A signal can be processed by a processing unit or processing module. The corresponding units / modules can be hardware, software, or a combination thereof. For example, one or more units / modules can be integrated circuits, such as field-programmable gate arrays (FPGAs) or application-specific integrated circuits (ASICs). It should be understood that if these modules are software, they can be retrieved by a processor, in whole or in part, individually or collectively, for processing, or in one or more instances as needed, and these modules themselves can include instructions for further deployment and instantiation.

[0185] While combinations of features are shown in the illustrated embodiments, it is not necessary to combine all features to achieve the advantages of the various embodiments of the invention. In other words, a system or method designed according to embodiments of the invention does not necessarily include all features shown in any of the figures or all portions schematically illustrated in the figures. Furthermore, selected features of one exemplary embodiment may be combined with selected features of other exemplary embodiments.

[0186] Although the invention has been described with reference to illustrative embodiments, this specification is not intended to be limiting. Those skilled in the art will recognize, upon referring to this description, various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A communication method, characterized in that, include: Send first configuration information to user equipment (UE), the first configuration information identifying a reference signal and the carrier frequency of the reference signal, the reference signal and the carrier frequency being used to determine channel information about the channel between the base station and the UE via a reconfigurable intelligent surface (RIS); A reference signal is transmitted by the RIS based on second configuration information, which configures the RIS to redirect different frequency components of the reference signal in different directions; Receive measurement information from the UE related to the measurement of the reference signal redirected by the RIS; The channel information is determined based on the transmitted reference signal and the received measurement information.

2. The method according to claim 1, characterized in that, It also includes at least one of the following: Data transmission is sent in one direction toward the RIS, and the data transmission is redirected by the RIS to the UE; or The UE receives data that has been redirected by the RIS prior to reception.

3. The method according to claim 1 or 2, characterized in that, Sending a reference signal includes sending at least one of the following: One or more narrowband reference signals are redirected by the RIS in different directions such that the reflected beams from the RIS do not overlap; One or more narrowband reference signals are redirected by the RIS in different directions such that the reflected beams from the RIS overlap. or A wideband reference signal, wherein the frequency components of the wideband reference signal are redirected in different directions by the RIS due to the prism-like effect of the RIS.

4. The method according to claim 2, characterized in that, Also includes: The multipath fading effect caused by the redirection of frequency components in a broadband data signal occupying a certain frequency range in different directions by the RIS is compensated by at least one of the following: Orthogonal frequency division multiplexing (OFDM) is used for the data transmission with subcarrier spacing, the subcarrier spacing depending on the measured frequency response of the broadband data signal interacting with the RIS; Configure the RIS to reduce deviation from the desired main direction; or The UE is instructed to perform channel equalization.

5. The method according to claim 4, characterized in that, The compensation is performed by configuring the RIS to reduce the deviation from the primary desired direction, and configuring the RIS to reduce the deviation from the primary desired direction includes configuring the RIS using third configuration information, which includes configuration information of at least one of the following: The RIS is configured to redirect a broadband data signal transmitted in a wide beam, the wide beam being larger than the deviation caused by a prism-like effect; The RIS is configured to divide the RIS into separate parts, each part redirecting a subset of the broadband data signals incident on the RIS; or The RIS is configured such that different sets of one or more configurable elements of the RIS redirect the broadband data signal incident on the RIS in a desired direction by configuring the configurable element at one end of the RIS to redirect the lowest frequency component of the broadband data signal in the desired direction, and then gradually changing the configuration of the other configurable elements of the RIS such that at the other end of the RIS, the configurable element is configured to redirect the highest frequency of the broadband data signal in the desired direction.

6. The method according to claim 1, 2, 4, or 5, characterized in that, Receiving measurement information from the UE includes receiving at least one of the following: An identifier for one or more reference signals having a received reference signal strength that satisfies a minimum threshold, wherein the received reference signal strength is one of the following: Reference signal received power of one or more reference signals RSRP); Reference signal strength indicator for one or more reference signals RSSI); Reference signal received quality of one or more reference signals RSRQ); The signal-to-noise ratio (SNR) of one or more reference signals; or Frequency response of receiving a broadband reference signal.

7. The method according to claim 1, 2, 4, or 5, characterized in that, Sending the first configuration information includes sending one or more of the following: The RIS is being used as an instruction to redirect signaling to the UE; An indication of the type of RIS used to redirect signaling to the UE; An identifier of the carrier frequency used to transmit the reference signal; or The identifier of the bandwidth of the reference signal.

8. The method according to claim 1, 2, 4, or 5, characterized in that, It also includes sending third configuration information to the RIS to configure the RIS to redirect the data transmission in an appropriate direction when the data transmission interacts with the RIS.

9. The method according to claim 1, 2, 4, or 5, characterized in that, It also includes sending the second configuration information to the RIS.

10. The method according to claim 1, 2, 4, or 5, characterized in that, Sending the second configuration information includes sending one or more of the following: The carrier frequency used to transmit the reference signal; The angle of arrival (AoA) of the reference signal at the RIS; When the reference signal is redirected, the reference signal is from one or more assumed angles of departure (AoD) of the RIS; The beamwidth of the redirected signal; or The RIS is divided to redirect reference signals at different frequencies.

11. An apparatus, characterized in that, include: Processing unit; A memory for storing instructions, wherein when the instructions are executed by the processing unit, the apparatus performs the method according to any one of claims 1 to 10.

12. A computer-readable medium, characterized in that, The device includes instructions that, when executed by the processing unit of the device, cause the device to perform the method according to any one of claims 1 to 10.

13. A method performed by a device, characterized in that, The method includes: Receive configuration information, the configuration information identifying a reference signal and the carrier frequency of the reference signal, the reference signal and the carrier frequency of the reference signal being used to determine channel information about the channel between the base station and the device via a reconfigurable intelligent surface (RIS); Receive the reference signal that has been redirected by the RIS; Measure the received reference signal; Send measurement information related to the measurement of the received reference signal.

14. The method according to claim 13, characterized in that, It also includes receiving data that has been redirected by the RIS.

15. The method according to claim 13 or 14, characterized in that, Receiving a reference signal that has been redirected by the RIS includes receiving at least one of the following: One or more narrowband reference signals are redirected by the RIS in different directions such that the reflected beams from the RIS do not overlap; One or more narrowband reference signals are redirected by the RIS in different directions such that the reflected beams from the RIS overlap. or A wideband reference signal, wherein the frequency components of the wideband reference signal are redirected in different directions by the RIS due to the prism-like effect of the RIS.

16. The method according to claim 15, characterized in that, It also includes receiving instructions to perform channel equalization to compensate for multipath fading effects caused by the redirection of frequency components in a wideband reference signal occupying a certain frequency range by the RIS in different directions.

17. The method according to claim 14 or 16, characterized in that, It also includes measuring at least one of the following: Frequency response to receiving a broadband reference signal; Reference signal received power (RSRP) of one or more reference signals; Reference signal strength indicator (RSSI) for one or more reference signals; The reference signal received quality (RSRQ) of one or more reference signals; or The signal-to-noise ratio (SNR) of one or more reference signals.

18. The method according to claim 14 or 16, characterized in that, It also includes sending at least one of the following: An identifier for one or more reference signals that satisfy a minimum threshold received reference signal strength; Measurement of the reference signal received power (RSRP) of one or more reference signals; Measurement of the reference signal strength indicator (RSSI) of one or more reference signals; Measurement of the reference signal received quality (RSRQ) of one or more reference signals; Measurement of the signal-to-noise ratio (SNR) of one or more reference signals; or Frequency response of receiving a broadband reference signal.

19. The method according to claim 13, 14, or 16, characterized in that, It also includes receiving one or more of the following: The RIS is being used to redirect signaling to an instruction from the device. An indication of the type of RIS used to redirect signaling to the device; An identifier of the carrier frequency used to transmit the reference signal; or The identifier of the bandwidth of the reference signal.

20. A device, characterized in that, The device includes: Processing unit; A memory for storing instructions, wherein when executed by the processing unit, the instructions cause the device to perform the method according to any one of claims 13 to 19.

21. A computer-readable medium, characterized in that, The instruction includes, when executed by the processing unit of the device, causing the device to perform the method according to any one of claims 13 to 19.

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