Sensing of reconfigurable smart surface (RIS)

Abstract

Systems, apparatus, processes, and computer-readable media for wireless communication are disclosed. For example, an example of a process includes transmitting a plurality of reference signal beams in a plurality of directions to a reconfigurable smart surface (RIS). The process may also include receiving a plurality of reflected reference signal beams in the plurality of directions from the RIS based on a plurality of backtracking reflection coefficients. The process may include measuring, for each of the plurality of backtracking reflection coefficients, a signal strength of each reflected reference signal beam in each of the plurality of directions. The process may also include determining a selected beam direction of the plurality of directions and a selected backtracking reflection coefficient of the plurality of backtracking reflection coefficients based on measuring the signal strength.

Description

Technical Field

[0001] The present disclosure generally relates to wireless communications.For example, aspects of the present disclosure relate to sensing (eg, sensing the position of) one or more reconfigurable smart surfaces (RIS), such as based on performing retro-reflection coefficient scanning. Background Art

[0002] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging and broadcasting. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency and power). Examples of such multiple access systems include fourth generation (4G) systems (such as long term evolution (LTE) systems, advanced LTE (LTE-A) systems or LTE-A Pro systems) and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may use techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA) or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting communication for multiple communication devices, which may be further referred to as user equipment (UE). Some wireless communication systems may support communication between UEs, which may involve direct transmission between two or more UEs.

[0003] As larger bandwidths are allocated for wireless cellular communication systems (e.g., including 5G and beyond 5G) and more use cases are introduced into cellular communication systems, multiplexing sensing signals and communication signals for joint communication and sensing may be an essential feature of existing or future wireless communication systems, such as to enhance the overall spectrum efficiency of the wireless communication network. Summary of the invention

[0004] The following presents a simplified summary of the invention related to one or more aspects disclosed herein. Thus, the following summary of the invention should neither be considered as an exhaustive overview related to all conceived aspects, nor should it be considered to identify key or decisive elements related to all conceived aspects or to delineate the scope associated with any particular aspect. Therefore, the sole purpose of the following summary of the invention is to present certain concepts related to one or more aspects of the mechanisms disclosed herein in a brief form before the detailed embodiments presented below.

[0005] Systems and techniques for wireless communications are described. According to at least one example, a method of wireless communications performed at a network device is provided. The method includes: sending a plurality of reference signal beams in a plurality of directions to a reconfigurable smart surface (RIS); receiving a plurality of reflected reference signal beams in the plurality of directions from the RIS based on a plurality of back-reflection coefficients; measuring the signal strength of each reflected reference signal beam in each direction of the plurality of directions for each back-reflection coefficient in the plurality of back-reflection coefficients; and determining a selected beam direction in the plurality of directions and a selected back-reflection coefficient in the plurality of back-reflection coefficients based on measuring the signal strength.

[0006] In another example, a network device for wireless communication is provided, the network device comprising: at least one memory; and at least one processor (e.g., configured in a circuit), the at least one processor coupled to the at least one memory. The at least one processor is configured to: output multiple reference signal beams in multiple directions for sending to a reconfigurable smart surface (RIS); receive multiple reflected reference signal beams in the multiple directions from the RIS based on multiple back-reflection coefficients; measure the signal strength of each reflected reference signal beam in each direction of the multiple directions for each back-reflection coefficient in the multiple back-reflection coefficients; and determine a selected beam direction in the multiple directions and a selected back-reflection coefficient in the multiple back-reflection coefficients based on measuring the signal strength.

[0007] In another example, a non-transitory computer-readable medium is provided, which has instructions stored thereon, which when executed by one or more processors cause the one or more processors to: output multiple reference signal beams in multiple directions for sending to a reconfigurable smart surface (RIS); receive multiple reflected reference signal beams in the multiple directions from the RIS based on multiple back-reflection coefficients; measure the signal strength of each reflected reference signal beam in each of the multiple directions for each of the multiple back-reflection coefficients; and determine a selected beam direction among the multiple directions and a selected back-reflection coefficient among the multiple back-reflection coefficients based on measuring the signal strength.

[0008] In another example, a device for wireless communication is provided. The device includes: a component for sending a plurality of reference signal beams in a plurality of directions to a reconfigurable smart surface (RIS); a component for receiving a plurality of reflected reference signal beams in the plurality of directions from the RIS based on a plurality of back-reflection coefficients; a component for measuring the signal strength of each reflected reference signal beam in each direction of the plurality of directions for each back-reflection coefficient in the plurality of back-reflection coefficients; and a component for determining a selected beam direction in the plurality of directions and a selected back-reflection coefficient in the plurality of back-reflection coefficients based on measuring the signal strength.

[0009] According to at least one other example, a method of wireless communication performed at a reconfigurable smart surface (RIS) is provided. The method includes: receiving a plurality of reference signal beams in a plurality of directions from a network device at the RIS; sending a plurality of reflected reference signal beams in the plurality of directions to the network device based on a plurality of back-reflection coefficients; and receiving a back-reflection coefficient message from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient among the plurality of back-reflection coefficients.

[0010] In another example, an apparatus for wireless communication is provided, the apparatus comprising at least one memory and at least one processor coupled to the at least one memory. The at least one processor is configured to: receive multiple reference signal beams in multiple directions from a network device; send multiple reflected reference signal beams in the multiple directions to the network device based on multiple back-reflection coefficients; and receive a back-reflection coefficient message from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient from the multiple back-reflection coefficients.

[0011] In another example, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium having instructions stored thereon, which, when executed by one or more processors, cause the one or more processors to: receive multiple reference signal beams in multiple directions from a network device; send multiple reflected reference signal beams in the multiple directions to the network device based on multiple back-reflection coefficients; and receive a back-reflection coefficient message from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient from the multiple back-reflection coefficients.

[0012] In another example, an apparatus for wireless communication is provided. The apparatus includes: a component for receiving multiple reference signal beams in multiple directions from a network device; a component for sending multiple reflected reference signal beams in multiple directions to the network device based on multiple back-reflection coefficients; and a component for receiving a back-reflection coefficient message from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient from the multiple back-reflection coefficients.

[0013] In some aspects, the network device or apparatus described herein is a UE, is part of a UE, and / or includes a UE, such as a wearable device, an extended reality (XR) device (e.g., a virtual reality (VR) device, an augmented reality (AR) device, or a mixed reality (MR) device), a head-mounted display (HMD) device, a wireless communication device, a mobile device (e.g., a mobile phone and / or a mobile phone and / or a so-called "smart phone" or other mobile device), a camera, a personal computer, a laptop computer, a server computer, a vehicle or a computing device or a component of a vehicle, another device, or a combination thereof. In some aspects, the apparatus includes one or more cameras for capturing one or more images. In some aspects, the apparatus also includes a display for displaying one or more images, notifications, and / or other displayable data. In some aspects, the apparatus may include one or more sensors (e.g., one or more inertial measurement units (IMUs), such as one or more gyroscopes, one or more gyrometers, one or more accelerometers, any combination thereof, and / or other sensors).

[0014] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim.

[0015] The foregoing and other features and aspects will become more apparent upon reference to the following description, claims and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are presented to aid in describing various aspects of the present disclosure and are provided solely for illustration and not limitation of the various aspects.

[0017] Figure 1 is a diagram illustrating an example wireless communication system that may be employed by the disclosed systems and techniques for sensing a reconfigurable smart surface (RIS) by retrospective reflection coefficient scanning in accordance with some aspects of the present disclosure.

[0018] Figure 2is a diagram illustrating an example of a decomposed base station architecture that may be employed by the disclosed systems and techniques for sensing RIS by retro-reflection coefficient scanning in accordance with some aspects of the present disclosure.

[0019] Figure 3 is a diagram illustrating an example of a frame structure that may be employed by the disclosed systems and techniques for sensing RIS by retroreflection coefficient scanning in accordance with some aspects of the present disclosure.

[0020] Figure 4 is a block diagram illustrating an example of a computing system of an electronic device that may be employed by the disclosed systems and techniques for sensing RIS by retroreflection coefficient scanning in accordance with some aspects of the present disclosure.

[0021] Figure 5 is a diagram illustrating an example of a wireless device utilizing radio frequency (RF) monostatic sensing techniques that may be employed by the disclosed systems and techniques described herein to determine one or more characteristics of a target object in accordance with some aspects of the present disclosure.

[0022] Figure 6 is a diagram illustrating an example of a receiver utilizing RF bistatic sensing techniques with a transmitter that may be employed by the disclosed systems and techniques described herein to determine one or more characteristics of a target object in accordance with some aspects of the present disclosure.

[0023] Figure 7 is a diagram illustrating an example of a receiver utilizing RF bistatic sensing techniques with multiple transmitters that may be employed by the disclosed systems and techniques described herein to determine one or more characteristics of a target object in accordance with some aspects of the present disclosure.

[0024] Figure 8 is a diagram illustrating example geometries for bistatic (or monostatic) sensing in accordance with some aspects of the present disclosure.

[0025] Fig. 9 is a diagram illustrating bistatic distances for bistatic sensing according to some aspects of the present disclosure.

[0026] Fig. 10A is a diagram illustrating an example of a system for performing RIS-assisted communications according to some aspects of the present disclosure.

[0027] Fig. 10B is a diagram illustrating an example of a system for performing RIS-assisted sensing according to some aspects of the present disclosure.

[0028] Fig.11A is a diagram illustrating an example of a RIS that may be employed by the disclosed systems and techniques for sensing the RIS by retroreflection coefficient scanning in accordance with some aspects of the present disclosure.

[0029] Fig. 11B is an example of some aspects of the present disclosure. Fig.11A Table of example phase shift and amplitude responses for different configurations of the RIS.

[0030] Fig.12 is a diagram illustrating an example of a system for sensing RIS by using retroreflection coefficients according to some aspects of the present disclosure.

[0031] Fig.13A is a diagram illustrating an example of a system for single-station sensing of RIS by retrospective reflection coefficient scanning according to some aspects of the present disclosure.

[0032] Fig. 13B is a diagram illustrating an example of a system for bistatic sensing of RIS by retrospective reflection coefficient scanning according to some aspects of the present disclosure.

[0033] Fig.14 is a diagram illustrating example signaling that may be employed by the disclosed systems and techniques for sensing RIS by retro-reflection coefficient scanning in accordance with some aspects of the present disclosure.

[0034] Fig.15A , Fig. 15B and Fig. 15C is a diagram illustrating signal generation of reflections using retroreflection coefficients associated with different angles of incidence in accordance with some aspects of the present disclosure.

[0035] Fig.16 is a diagram illustrating an example of retroreflection coefficient beam scanning according to some aspects of the present disclosure.

[0036] Fig.17 is a diagram illustrating example RIS on / off modes according to some aspects of the present disclosure.

[0037] Fig.18 is a flow chart illustrating an example of a process for wirelessly communicating at a network device utilizing a method for sensing RIS by retrospective reflection coefficient scanning according to some aspects of the present disclosure.

[0038] Fig.19 is a flow chart illustrating an example of a process for wirelessly communicating at a RIS utilizing a method for sensing the RIS by retrospective reflection coefficient scanning in accordance with some aspects of the present disclosure.

[0039] Fig. 20 is a block diagram illustrating an example of a computing system that may be employed by the disclosed systems and techniques for sensing RIS by retroreflection coefficient scanning in accordance with some aspects of the present disclosure. DETAILED DESCRIPTION

[0040] For illustrative purposes, some aspects of the present disclosure are provided below. Without departing from the scope of the present disclosure, alternative aspects can be designed. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted, so as not to make the relevant details of the present disclosure difficult to understand. Some aspects described herein can be applied independently, and some of them can be applied in combination, which is obvious to those skilled in the art. In the following description, specific details are set forth for explanation purposes to provide a thorough understanding of various aspects of the application. However, it is obvious that various aspects can be practiced without these specific details. Each drawing and description are not intended to be restrictive.

[0041] The following description provides only example aspects and is not intended to limit the scope, applicability or configuration of the present disclosure. Instead, the following description of the example aspects will provide a description that can be used to implement the example aspects to those skilled in the art. It should be understood that various changes may be made to the function and arrangement of the elements without departing from the scope of the present application as set forth in the appended claims.

[0042] Radar sensing systems use radio frequency (RF) waveforms to perform RF sensing to determine or estimate one or more characteristics of a target object, such as the distance, angle, and / or speed of the target object. The target object may include a vehicle, an obstacle, a user, a building, or other objects. A typical radar system includes at least one transmitter, at least one receiver, and at least one processor. When a receiver co-located with a transmitter is used, the radar sensing system can perform single-station sensing. When a receiver is positioned at a first device away from a transmitter of a second device is used, the radar system can perform dual-station sensing. Similarly, when multiple receivers of multiple devices are used that are all positioned away from at least one transmitter of at least one device, the radar system can perform multi-station sensing.

[0043] During operation of the radar sensing system, a transmitter transmits an electromagnetic (EM) signal in the RF domain toward a target object. The signal reflects from the target object to produce one or more reflected signals that provide information or properties about the target, such as the position and velocity of the target object. At least one receiver receives the one or more reflected signals, and at least one processor that may be associated with the at least one receiver utilizes information from the one or more reflected signals to determine information or properties of the target object. The target object may also be referred to herein as a target.

[0044] Generally speaking, RF sensing involves monitoring moving targets with different motions (e.g., moving cars or pedestrians, human body motions such as breathing, and / or other micro-motions associated with the target). Doppler (which measures phase changes in the signal and indicates motion) is an important characteristic for sensing of targets.

[0045] In some cases, a radar sensing signal, such as a sensing reference signal (S-RS), which may be referred to as a radar reference signal (RS), may be designed and used for sensing purposes. A radar RS does not contain any communication information. In contrast, a communication RS, such as a demodulation reference signal (DMRS), is typically designed and used only for communication purposes, such as estimating channel parameters for communication.

[0046] Cellular communication systems are designed to send communication signals on designated communication bands (e.g., 23 gigahertz (GHz), 3.5 GHz, etc. for 5G / NR, 2.2 GHz, etc. for LTE). RF sensing systems are designed to send RF sensing signals on designated radar RF bands (e.g., 77 GHz for autonomous driving). It is likely that the spectrum used for communication and sensing will be shared in future cellular communication systems, in which case communication and sensing should be considered jointly.

[0047] In some cases, as wireless communication systems (e.g., including cellular communication systems such as 4G / LTE, 5G / NR and beyond) are allocated greater bandwidth and more use cases are introduced into wireless communication systems, multiplexing sensing signals and communication signals (e.g., via time division multiplexing and / or frequency division multiplexing) for joint communication and sensing may be an essential feature of existing and future wireless communication systems. Performing wireless communication and radar sensing simultaneously may provide cost-effective deployment for both radar and communication systems.

[0048] Joint communication and radar sensing can provide mutual performance gains. For example, sensing information such as Doppler measurements can be used to improve communication link quality (e.g., sensing-assisted communication). In addition, cooperative sensing may be more feasible for wireless communication networks (e.g., communication-assisted sensing).

[0049] Integrated sensing and communication (ISAC) using multiplexed sensing and communication signals can be considered a key 5G and sixth generation (6G) feature for the cellular industry. ISAC can provide cost effectiveness by using shared RF and possibly baseband hardware (HW) for both sensing and communication. ISAC can also provide spectrum effectiveness by providing always-on availability of spectrum for both sensing use cases and communication use cases. ISAC can be used for a variety of different use cases, including but not limited to macro sensing (e.g., weather monitoring; autonomous driving; dynamic mapping; low-altitude airspace, such as unmanned aerial vehicles, management; and intruder detection), micro sensing (e.g., gesture recognition, vital sign detection, and high-resolution imaging using terahertz signals), and sensing-assisted communication (e.g., beam management). Some contributions have been made in 3GPP for ISAC. For example, some companies have proposed some requirements and network architectures for ISAC in 3GPP Stand-Alone 1 (SA1). In addition, in China, International Mobile Telecommunications (IMT)-2020 and IMT-2030 are promoting ISAC for 5G-A and 6G.

[0050] Reconfigurable smart surfaces (RIS) may be employed for sensing and / or communication. Traditionally, reconfigurable smart surfaces (RIS) have been used for communication. However, RIS may also be employed to assist in sensing one or more objects of an ISAC system (e.g., to determine the location, position, and / or other characteristics of one or more objects). RIS-assisted sensing may require a higher accuracy (e.g., higher precision) of RIS location than required for RIS-assisted communication.

[0051] RIS can shape the wireless environment into a desired form at a low cost. In practice, RIS has three types of specific implementations, including reflection (e.g., where the signal can be reflected by the RIS), transmission (e.g., where the signal can penetrate the RIS), and hybrid (e.g., where the RIS can have dual functions of reflection and transmission).

[0052] The RIS is a programmable array structure that can be used to control the propagation of electromagnetic (EM) waves (e.g., steer an RF beam) by changing the electrical and magnetic properties of the surface of the RIS. The RIS includes an array of metamaterial RIS elements, which consists of an ultra-thin surface with multiple wavelength scatterers embedded. The electromagnetic properties of the RIS elements can be dynamically controlled by applying control signals to tunable elements (e.g., Pin diodes) on the RIS elements, which can enable active and intelligent modulation of electromagnetic waves in a programmable manner to form an electromagnetic field with controllable amplitude, phase, polarization and / or frequency. For example, the electromagnetic response of the RIS elements (e.g., steering the phase shift of the RF beam) can be controlled by a programmable Pin diode.

[0053] Conventional sensing without using RIS may present many challenges, which may include, but are not limited to, limited coverage distance due to return transmissions, coverage holes (e.g., holes in the coverage area) when there is no line-of-sight (LOS) link between a network device (e.g., a base station) and a target, and insufficient number of positioning reference points because one network device (e.g., a base station) can only provide a single reference point. Employing RIS to assist sensing (e.g., RIS-based sensing) may provide many benefits, including, but not limited to: extending coverage distance by using RIS beamforming, eliminating coverage holes by operating RIS as a relay device (e.g., RIS may be flexibly deployed to have a LOS link to a coverage hole of a base station), and adding additional reference points for the location of the RIS.

[0054] In order to realize the benefits of RIS-based sensing, the network device (e.g., a base station or user equipment) should know the location of the RIS. For example, during operation of the disclosed system, if the location of the RIS is unknown (e.g., the RIS does not have global positioning system (GPS) capabilities), the network device may first estimate the location of the RIS before using the RIS to assist in sensing. After the network device obtains the location of the RIS, the network device may determine a specific beam radiated from the RIS and may use the location of the RIS as a reference point for sensing. In some aspects of the present disclosure, systems, apparatuses, methods (also referred to as processes), and computer-readable media (collectively referred to herein as "systems and techniques") are described herein that provide a solution for a network device (e.g., a base station or user equipment) to sense the RIS and estimate the location of the RIS. In some aspects, the systems and techniques may employ retro-reflection coefficient scanning.

[0055] Additional aspects of the disclosure are described in more detail below.

[0056] As used herein, the terms "user equipment" (UE) and "network entity" are not intended to be dedicated to or otherwise limited to any particular radio access technology (RAT), unless otherwise specified. In general, a UE can be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, and / or a tracking device, etc.), a wearable device (e.g., a smart watch, smart glasses, a wearable ring, and / or an extended reality (XR) device (such as a virtual reality (VR) headset, an augmented reality (AR) headset or glasses, or a mixed reality (MR) headset)), a vehicle (e.g., a car, a motorcycle, a bicycle, etc.), and / or an Internet of Things (IoT) device, etc., for a user to communicate on a wireless communication network. A UE can be mobile or can be stationary (e.g., at certain times) and can communicate with a radio access network (RAN). As used herein, the term "UE" may be interchangeably referred to as an "access terminal" or "AT," a "client device," a "wireless device," a "subscriber device," a "subscriber terminal," a "subscriber station," a "user terminal" or "UT," a "mobile device," a "mobile terminal," a "mobile station," or variations thereof. Generally speaking, a UE may communicate with a core network via a RAN, and through the core network, the UE may connect to external networks (such as the Internet) and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through a wired access network, a wireless local area network (WLAN) network (e.g., based on IEEE 802.11 communication standards, etc.), and the like.

[0057] The network entity may be implemented in an aggregated or monolithic base station architecture, or alternatively, in a disaggregated base station architecture, and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near-RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC. A base station (e.g., with an aggregated / monolithic base station architecture or a disaggregated base station architecture) may operate according to one of several RATs communicating with a UE (depending on the network in which it is deployed), and may alternatively be referred to as an access point (AP), a network node, a Node B (NB), an evolved Node B (eNB), a next generation eNB (ng-eNB), a new radio (NR) Node B (also referred to as a gNB or gNode B), etc. A base station may be primarily used to support wireless access for UEs, including supporting data, voice, and / or signaling connections for the supported UEs. In some systems, a base station may provide edge node signaling functionality, while in other systems, a base station may provide additional control and / or network management functionality. The communication link by which a UE can transmit signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). The communication link by which a base station can transmit signals to a UE is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term traffic channel (TCH) may refer to an uplink, a reverse or downlink, and / or a forward traffic channel.

[0058] The term "network entity" or "base station" (e.g., having an aggregated / monolithic base station architecture or a disaggregated base station architecture) may refer to a single physical transmit-receive point (TRP) or multiple physical transmit-receive points (TRPs), which may or may not be co-located. For example, where the term "network entity" or "base station" refers to a single physical TRP, the physical TRP may be a base station antenna corresponding to a cell (or several cell sectors) of the base station. Where the term "network entity" or "base station" refers to multiple co-located physical TRPs, these physical TRPs may be antenna arrays of the base station (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming). Where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transmission medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs may be the serving base station receiving the measurement report from the UE and the neighbor base station whose reference radio frequency (RF) signal (or "reference signal" for short) the UE is measuring. Because, as used herein, a TRP is the point at which a base station transmits and receives wireless signals, references to transmitting from a base station or receiving at a base station should be understood to refer to a specific TRP of a base station.

[0059] In some implementations of supporting UE positioning, a network entity or base station may not support wireless access for a UE (e.g., may not support data, voice, and / or signaling connections for a UE), but may instead send a reference signal to be measured by the UE to the UE, and / or may receive and measure signals sent by the UE. Such a base station may be referred to as a positioning tower (e.g., in the case of sending a signal to the UE) and / or as a position measurement unit (e.g., in the case of receiving and measuring a signal from the UE).

[0060] RF signals include electromagnetic waves of a given frequency that transmit information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same transmitted RF signal on different paths between a transmitter and a receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal" where it is clear from the context that the term "signal" refers to a wireless signal or an RF signal.

[0061] According to various aspects, Figure 1An exemplary wireless communication system 100 that can be employed by the disclosed systems and techniques described herein for sensing RIS by back-reflection coefficient scanning is illustrated. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 and various UEs 104. In some aspects, the base stations 102 may also be referred to as "network entities" or "network nodes". One or more of the base stations 102 may be implemented in an aggregated or monolithic base station architecture. Additionally or alternatively, one or more of the base stations 102 may be implemented in a decomposed base station architecture and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near-RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). On the one hand, the macro cell base station may include an eNB and / or an ng-eNB (where the wireless communication system 100 corresponds to a long term evolution (LTE) network), or a gNB (where the wireless communication system 100 corresponds to an NR network), or a combination of both, and the small cell base station may include a femto cell, a pico cell, a micro cell, etc.

[0062] The base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or a 5G core (5GC)) through a backhaul link 122, and interface to one or more location servers 172 (which may be part of the core network 170 or may be external to the core network 170) through the core network 170. Among other functions, the base stations 102 may perform functions related to one or more of the following: delivering user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC or 5GC) through a backhaul link 134 (which may be wired and / or wireless).

[0063] Base station 102 can communicate wirelessly with UE 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. In one aspect, base station 102 in each coverage area 110 can support one or more cells. A "cell" is a logical communication entity for communicating with a base station (e.g., on a certain frequency resource, referred to as a carrier frequency, component carrier, carrier, frequency band, etc.), and can be associated with an identifier (e.g., a physical cell identifier (PCI), a virtual cell identifier (VCI), a cell global identifier (CGI)) to distinguish cells operating via the same or different carrier frequencies. In some cases, different cells can be configured according to different protocol types (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB) or other protocol types) that can provide access to different types of UEs. Since a cell is supported by a specific base station, the term "cell" can refer to either or both of a logical communication entity and a base station supporting the logical communication entity, depending on the context. In addition, since a TRP is typically a physical transmission point of a cell, the terms "cell" and "TRP" can be used interchangeably. In some cases, the term "cell" may also refer to a geographic coverage area (eg, a sector) of a base station, as long as a carrier frequency can be detected and used for communications within some portion of the geographic coverage area 110.

[0064] Although the geographic coverage areas 110 of neighboring macrocell base stations 102 may partially overlap (e.g., in a handover area), some areas of the geographic coverage areas 110 may substantially overlap with the larger geographic coverage area 110. For example, a small cell base station 102' may have a coverage area 110' that substantially overlaps with the coverage area 110 of one or more macrocell base stations 102. A network that includes both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB) that may provide services to a restricted group referred to as a closed subscriber group (CSG).

[0065] The communication link 120 between the base station 102 and the UE 104 may include uplink (also known as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (also known as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric for the downlink and uplink (e.g., more or fewer carriers may be allocated to the downlink than to the uplink).

[0066] The wireless communication system 100 may further include a WLAN AP 150 in communication with a WLAN station (STA) 152 via a communication link 154 in an unlicensed spectrum (e.g., 5 gigahertz (GHz)). When communicating in the unlicensed spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or a listen-before-talk (LBT) procedure before communicating to determine whether a channel is available. In some examples, the wireless communication system 100 may include a device (e.g., UE, etc.) that communicates with one or more UEs 104, base stations 102, APs 150, etc. using an ultra-wideband (UWB) spectrum. The UWB spectrum may range from 3.1 GHz to 10.5 GHz.

[0067] The small cell base station 102' can operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell base station 102' can adopt LTE or NR technology and use the same 5GHz unlicensed spectrum used by the WLAN AP 150. The small cell base station 102' adopting LTE and / or 5G in the unlicensed spectrum can boost the coverage of the access network and / or increase the capacity of the access network. NR in the unlicensed spectrum can be referred to as NR-U. LTE in the unlicensed spectrum can be referred to as LTE-U, license-assisted access (LAA) or MulteFire.

[0068] The wireless communication system 100 may further include a millimeter wave (mmW) base station 180 that can operate in mmW frequencies and / or near mmW frequencies to communicate with UE 182. The mmW base station 180 can be implemented in an aggregated or monolithic base station architecture, or alternatively, in a decomposed base station architecture (e.g., including one or more of CU, DU, RU, near RT RIC, or non-RT RIC). Extremely high frequency (EHF) is part of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz, and a wavelength between 1 mm and 10 mm. The radio waves in this band may be referred to as millimeter waves. Near mmW can be extended down to a frequency of 3 GHz, and a wavelength of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, which is also referred to as centimeter waves. Communications using mmW and / or near mmW radio frequency bands have high path loss and a relatively short range. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and / or receive) on the mmW communication link 184 to compensate for the extremely high path loss and short range. In addition, it should be understood that in alternative configurations, one or more base stations 102 may also transmit using mmW or near-mmW and beamforming. Therefore, it should be understood that the foregoing illustrations are merely examples and should not be construed as limiting the various aspects disclosed herein.

[0069] Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node or entity (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node), and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal to the receiving device. In order to change the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that broadcast the RF signal. For example, a network node can use an array of antennas (referred to as a "phased array" or "antenna array") that produces a beam of RF waves that can be "steered" to point in different directions without actually moving the antenna. Specifically, the RF current from the transmitter is fed to the individual antennas in the correct phase relationship so that the radio waves from the separate antennas are added together in the desired direction to increase the radiation, and canceled in the undesired direction to suppress the radiation.

[0070] The transmit beams can be quasi-co-located, which means that they appear to the receiver (e.g., UE) to have the same parameters, regardless of whether the transmit antennas of the network nodes themselves are physically co-located. In NR, there are four types of quasi-co-location (QCL) relationships. Specifically, a given type of QCL relationship means that certain parameters about the second reference RF signal on the second beam can be derived based on information about the source reference RF signal on the source beam. Therefore, if the source reference RF signal is QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay and delay spread of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type D, the receiver may use the source reference RF signal to estimate spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0071] In receive beamforming, a receiver uses a receive beam to amplify an RF signal detected on a given channel. For example, a receiver may increase the gain setting of an antenna array in a particular direction and / or adjust the phase setting of an antenna array in a particular direction to amplify (e.g., increase its gain level) the RF signal received from that direction. Thus, when a receiver is referred to as performing beamforming in a certain direction, this means that the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain of other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), etc.) of the RF signal received from that direction.

[0072] The receive beams may be spatially correlated. The spatial relationship means that the parameters of the transmit beam for the second reference signal may be derived from information about the receive beam for the first reference signal. For example, the UE may receive one or more reference downlink reference signals (e.g., positioning reference signal (PRS), tracking reference signal (TRS), phase tracking reference signal (PTRS), cell-specific reference signal (CRS), channel state information reference signal (CSI-RS), primary synchronization signal (PSS), secondary synchronization signal (SSS), synchronization signal block (SSB), etc.) from a network node or entity (e.g., a base station) using a specific receive beam. The UE may then form a transmit beam based on the parameters of the receive beam for transmitting one or more uplink reference signals (e.g., uplink positioning reference signal (UL-PRS), sounding reference signal (SRS), demodulation reference signal (DMRS), PTRS, etc.) to the network node or entity (e.g., a base station).

[0073] Note that, depending on the entity forming the "downlink" beam, the beam can be a transmit beam or a receive beam. For example, if a network node or entity (e.g., a base station) is forming a downlink beam to send a reference signal to a UE, the downlink beam is a transmit beam. However, if the UE is forming a downlink beam, the downlink beam is a receive beam that receives a downlink reference signal. Similarly, depending on the entity forming the "uplink" beam, the beam can be a transmit beam or a receive beam. For example, if a network node or entity (e.g., a base station) is forming an uplink beam, the uplink beam is an uplink receive beam, and if the UE is forming an uplink beam, the uplink beam is an uplink transmit beam.

[0074] In 5G, the spectrum in which the wireless network nodes or entities (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges: FR1 (from 450 megahertz (MHz) to 6000 MHz), FR2 (from 24250 MHz to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system (such as 5G), one of the carrier frequencies is referred to as a "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", and the remaining carrier frequencies are referred to as "secondary carriers" or "secondary serving cells" or "SCells". In carrier aggregation, the anchor carrier is a carrier operating on the primary frequency (e.g., FR1) used by the UE 104 / 182 and the cell in which the UE 104 / 182 performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels and can be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2), which can be configured and can be used to provide additional radio resources once an RRC connection is established between the UE 104 and the anchor carrier. In some cases, the secondary carrier may be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals, for example, since the primary uplink carrier and the primary downlink carrier are usually UE-specific, those signaling information and signals specific to the UE may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. This is also true for the uplink primary carrier. The network is able to change the primary carrier of any UE 104 / 182 at any time. This is done, for example, to balance the load on different carriers. Since a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency or component carrier through which some base stations communicate, the terms "cell", "serving cell", "component carrier", "carrier frequency", etc. may be used interchangeably.

[0075] For example, still refer to Figure 1, one of the frequencies used by the macrocell base station 102 may be an anchor carrier (or "PCell"), and the other frequencies used by the macrocell base station 102 and / or the mmW base station 180 may be secondary carriers ("SCells"). In carrier aggregation, the base station 102 and / or the UE 104 may use a spectrum of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz) bandwidth per carrier, with up to a total of Yx MHz (x component carriers) in each direction for transmission. The component carriers may be adjacent to each other or may not be adjacent to each other in the spectrum. The allocation of carriers may be asymmetric with respect to the downlink and uplink (e.g., more or fewer carriers may be allocated to the downlink than to the uplink). The simultaneous transmission and / or reception of multiple carriers enables the UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically result in a doubling of the data rate (i.e., 40 MHz) compared to the data rate obtained with a single 20 MHz carrier.

[0076] In order to operate on multiple carrier frequencies, the base station 102 and / or the UE 104 are equipped with multiple receivers and / or transmitters. For example, the UE 104 may have two receivers, namely "receiver 1" and "receiver 2", where "receiver 1" is a multi-band receiver that can be tuned to band (i.e., carrier frequency) "X" or band "Y", and "receiver 2" is a single-band receiver that can be tuned to only band "Z". In this example, if the UE 104 is being served in band "X", the band "X" will be referred to as the PCell or active carrier frequency, and "receiver 1" will need to tune from band "X" to band "Y" (SCell) to measure band "Y" (and vice versa). In contrast, regardless of whether the UE 104 is being served in band "X" or band "Y", due to the separate "receiver 2", the UE 104 can measure band "Z" without interrupting the service on band "X" or band "Y".

[0077] The wireless communication system 100 may further include a UE 164 that may communicate with the macrocell base station 102 over the communication link 120 and / or communicate with the mmW base station 180 over the mmW communication link 184. For example, the macrocell base station 102 may support a PCell and one or more SCells for the UE 164, and the mmW base station 180 may support one or more SCells for the UE 164.

[0078] The wireless communication system 100 may further include one or more UEs (such as UE 190) that are indirectly connected to one or more communication networks via one or more device-to-device (D2D) or peer-to-peer (P2P) links (referred to as “side links”). Figure 1 In the example of FIG. 1 , UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of base stations 102 (e.g., UE 190 can indirectly obtain cellular connectivity through the D2D P2P link), and has a D2D P2P link 194 with WLAN STA 152 connected to WLAN AP 150 (UE 190 can indirectly obtain WLAN-based Internet connectivity through the D2D P2P link). In an example, D2D P2P links 192 and 194 can use any well-known D2D RAT (such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), As mentioned above, UE 104 and UE 190 can be configured to communicate using sidelink communications. In some cases, the sidelink transmission can include a request for feedback from the receiving UE (e.g., hybrid automatic repeat request (HARQ)).

[0079] Figure 2 is a diagram illustrating an example of a decomposed base station architecture that can be employed by the disclosed systems and techniques for sensing RIS by back-reflection coefficient scanning. The deployment of a communication system (such as a 5G NR system) can be arranged in a variety of ways with various components or constituent parts. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or network equipment (such as a base station (BS)), or one or more units (or one or more components) that perform base station functionality can be implemented in an aggregated or decomposed architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an AP, a transmit receive point (TRP) or a cell, etc.) can be implemented as an aggregated base station (also called a stand-alone BS or a monolithic BS) or a decomposed base station.

[0080] The aggregated base station can be configured to utilize a radio protocol stack physically or logically integrated within a single RAN node. The decomposed base station can be configured to utilize a protocol stack physically or logically distributed between two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, the CU can be implemented within a RAN node, and one or more DUs can be co-located with the CU, or alternatively, can be geographically or virtually distributed in one or more other RAN nodes. The DU can be implemented to communicate with one or more RUs. Each of the CU, DU, and RU can also be implemented as a virtual unit, namely a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0081] Base station type operations or network designs may take into account the aggregated nature of base station functionality. For example, a disaggregated base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (network configurations such as those initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which may enable flexibility in network design. Individual units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0082] As mentioned earlier, Figure 2 A diagram illustrating an example decomposed base station 201 architecture is shown. The decomposed base station 201 architecture may include one or more central units (CUs) 211 that may communicate directly with a core network 223 via a backhaul link, or indirectly with a core network 223 through one or more decomposed base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 227 via an E2 link, or a non-real-time (non-RT) RIC 217 associated with a service management and orchestration (SMO) framework 207, or both. The CU 211 may communicate with one or more distributed units (DUs) 231 via respective midhaul links, such as an F1 interface. The DU 231 may communicate with one or more radio units (RUs) 241 via respective fronthaul links. The RU 241 may communicate with respective UEs 221 via one or more RF access links. In some implementations, a UE 221 may be served simultaneously by multiple RUs 241.

[0083] Each of the units (i.e., CU 211, DU 231, RU 241, and near-RT RIC 227, non-RT RIC 217, and SMO framework 207) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interfaces of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, the unit may include a wired interface configured to receive or send signals to one or more of the other units on a wired transmission medium. Additionally, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) configured to receive or send signals, or both, to one or more of the other units on a wireless transmission medium.

[0084] In some aspects, CU 211 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface configured to communicate signals with other control functions hosted by CU 211. CU 211 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 211 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 211 may be implemented to communicate with DU231 for network control and signaling.

[0085] DU 231 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 241. In some aspects, DU 231 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) at least in part according to a functional split such as defined by the Third Generation Partnership Project (3GPP). In some aspects, DU 231 may further host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 231 or with control functions hosted by CU 211.

[0086] Lower layer functionality may be implemented by one or more RUs 241. In some deployments, a RU 241 controlled by a DU 231 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, the RU 241 may be implemented to handle over-the-air (OTA) communications with one or more UEs 221. In some implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 241 may be controlled by the corresponding DU 231. In some scenarios, this configuration may enable the implementation of the DU 231 and the CU 211 in a cloud-based RAN architecture (such as a vRAN architecture).

[0087] The SMO framework 207 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 207 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 207 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 291) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 211, DU 231, RU 241, and near-RT RIC 227. In some specific implementations, the SMO framework 207 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 213) via the O1 interface. Additionally, in some specific implementations, the SMO framework 207 may communicate directly with one or more RUs 241 via the O1 interface. The SMO framework 207 may also include a non-RT RIC 217 configured to support the functionality of the SMO framework 207 .

[0088] The non-RT RIC 217 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 227. The non-RT RIC 217 may be coupled to or in communication with the near-RT RIC 227 (such as via an A1 interface). The near-RT RIC 227 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 211, one or more DUs 231, or both, and the O-eNB 213 with the near-RTRIC 227.

[0089] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 227, the non-RT RIC 217 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 227 and may be received from a non-network data source or from a network function at the SMO framework 207 or the non-RT RIC 217. In some examples, the non-RT RIC 217 or the near-RT RIC 227 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 217 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 207 (such as via reconfiguration of O1) or via creation of RAN management policies (such as A1 policies).

[0090] Various radio frame structures may be used to support downlink transmissions, uplink transmissions, and sidelink transmissions between network nodes (eg, base stations and UEs). Figure 3 is a diagram 300 illustrating an example of a frame structure that may be employed by the disclosed systems and techniques for sensing RIS by retro-reflection coefficient scanning. Other wireless communication technologies may have different frame structures and / or different channels.

[0091] NR (and LTE) utilizes OFDM on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. However, unlike LTE, NR also has the option of using OFDM on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often called tones, frequency bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are transmitted in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of the subcarriers can be 15kHz, and the minimum resource allocation (resource block) can be 12 subcarriers (or 180kHz). Therefore, for a system bandwidth of 1.25 megahertz (MHz), 2.5MHz, 5MHz, 10MHz, or 20MHz, the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may also be divided into multiple subbands. For example, a subband may cover 1.08 MHz (ie, 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, or 20 MHz, respectively.

[0092] LTE supports a single parameter set (subcarrier spacing, symbol length, etc.). In contrast, NR can support multiple parameter sets (μ). For example, 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz or larger subcarrier spacing (SCS) may be available. Table 1 provided below lists some different parameters for different NR parameter sets.

[0093]

[0094] Table 1

[0095] In one example, a 15 kHz parameter set is used. Thus, in the time domain, a 10 millisecond (ms) frame is divided into 10 equally sized subframes, each subframe is 1 ms, and each subframe includes one time slot. Figure 3 , time is represented horizontally (eg, on the X-axis), where time increases from left to right, and frequency is represented vertically (eg, on the Y-axis), where frequency increases (or decreases) from bottom to top.

[0096] A resource grid may be used to represent time slots, each of which includes one or more time-concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)) in the frequency domain. Figure 3 An example of a resource block (RB) 302 is illustrated. Data or information for joint communication and sensing may be included in one or more RBs 302. RBs 302 are arranged by placing the time domain on the horizontal (or x) axis and the frequency domain on the vertical (or y) axis. As shown, RBs 302 may be 180 kilohertz (kHz) wide in frequency and one slot long in time (where a slot is 1 millisecond (ms) in time). In some cases, a slot may include fourteen symbols (e.g., in slot configuration 0). RBs 302 include twelve subcarriers (along the y-axis) and fourteen symbols (along the x-axis).

[0097] The intersection of a symbol and a subcarrier may be referred to as a resource element (RE) 304 or a tone. Figure 3 The RB 302 of the RF includes a plurality of REs, which include resource elements (REs) 304. For example, RE 304 is 1 subcarrier×1 symbol (e.g., OFDM symbol) and is the smallest discrete part of a subframe. RE 304 includes a single complex value representing data from a physical channel or signal. The number of bits carried by each RE 304 depends on the modulation scheme.

[0098] In some aspects, some REs 304 may be used to send downlink reference (pilot) signals (DL-RS). DL-RS may include positioning reference signals (PRS), tracking reference signals (TRS), phase tracking reference signals (PTRS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), primary synchronization signals (PSS), secondary synchronization signals (SSS), etc. Figure 3 The resource grid of exemplifies exemplary locations (labeled as “R”) of REs 304 for transmitting DL-RS.

[0099] Figure 4 4 is a block diagram illustrating an example of a computing system 470 of an electronic device 407 that may be employed by the disclosed systems and techniques for sensing RIS by back-reflection coefficient scanning. The electronic device 407 is an example of a device that may include hardware and software for connecting and exchanging data with other devices and systems using a communication network (e.g., a third generation partner network such as a fifth generation (5G) / new radio (NR) network, a fourth generation (4G) / long term evolution (LTE) network, a WiFi network, or other communication network). For example, the electronic device 407 may include or be part of a mobile device (e.g., a mobile phone), a wearable device (e.g., a web-connected or smartwatch), an extended reality device (e.g., a virtual reality (VR) device, an augmented reality (AR) device, or a mixed reality (MR) device), a personal computer, a laptop computer, a tablet computer, an Internet of Things (IoT) device, a wireless access point, a router, a vehicle or a component of a vehicle, a server computer, a robotic device, and / or other devices used by a user to communicate over a wireless communication network. In some cases, device 407 may be referred to as user equipment (UE), such as when referring to a device configured to communicate using 5G / NR, 4G / LTE, or other telecommunication standards. In some cases, the device may be referred to as a station (STA), such as when referring to a device configured to communicate using the Wi-Fi standard.

[0100] The computing system 470 includes software and hardware components that may be electrically or communicatively coupled via a bus 489 (or may communicate in other ways, as appropriate). For example, the computing system 470 includes one or more processors 484. The one or more processors 484 may include one or more CPUs, ASICs, FPGAs, APs, GPUs, VPUs, NSPs, microcontrollers, dedicated hardware, any combination thereof, and / or other processing devices and / or systems. The bus 489 may be used by the one or more processors 484 to communicate between cores and / or with one or more memory devices 486.

[0101] The computing system 470 may also include one or more memory devices 486, one or more digital signal processors (DSPs) 482, one or more subscriber identity modules (SIMs) 474, one or more modems 476, one or more wireless transceivers 478, one or more antennas 487, one or more input devices 472 (e.g., a camera, a mouse, a keyboard, a touch-sensitive screen, a touchpad, a keypad, a microphone or microphone array, etc.), and one or more output devices 480 (e.g., a display, a speaker, a printer, etc.).

[0102] One or more wireless transceivers 478 can receive wireless signals (e.g., signal 488) via antenna 487 from one or more other devices such as other user devices, network devices (e.g., base stations such as evolved Node B (eNB) and / or gNodeB (gNB)), WiFi access points (APs) such as routers, range extenders, etc.), cloud networks, etc. In some examples, computing system 470 may include multiple antennas or antenna arrays that can facilitate simultaneous transmission and reception functionality. Antenna 487 can be an omnidirectional antenna so that RF signals can be received from all directions and RF signals can be transmitted in all directions. Wireless signal 488 can be sent via a wireless network. The wireless network can be any wireless network, such as a cellular or telecommunications network (e.g., 3G, 4G, 5G, etc.), a wireless local area network (e.g., a WiFi network), a Bluetooth TM network and / or other networks. In some examples, one or more wireless transceivers 478 may include an RF front end that includes one or more components such as an amplifier, a mixer for down-converting a signal (also known as a signal multiplier), a frequency synthesizer (also known as an oscillator) that provides a signal to the mixer, a baseband filter, an analog-to-digital converter (ADC), one or more power amplifiers, and other components. The RF front end generally can handle the selection of the wireless signal 488 and the conversion of the wireless signal to baseband or intermediate frequency, and can convert the RF signal to the digital domain.

[0103] In some cases, computing system 470 may include a coding-decoding device (or CODEC) configured to encode and / or decode data transmitted and / or received using one or more wireless transceivers 478. In some cases, computing system 470 may include an encryption-decryption device or component configured to encrypt and / or decrypt data transmitted and / or received by one or more wireless transceivers 478 (e.g., in accordance with the Advanced Encryption Standard (AES) and / or Data Encryption Standard (DES) standards).

[0104] One or more SIMs 474 can each securely store an International Mobile Subscriber Identity (IMSI) number and associated keys assigned to a user of the electronic device 407. The IMSI and keys can be used to identify and authenticate subscribers when accessing a network provided by a network service provider or operator associated with one or more SIMs 474. One or more modems 476 can modulate one or more signals to encode information for transmission using one or more wireless transceivers 478. One or more modems 476 can also demodulate signals received by one or more wireless transceivers 478 to decode the transmitted information. In some examples, one or more modems 476 can include a WiFi modem, a 4G (or LTE) modem, a 5G (or NR) modem, and / or other types of modems. One or more modems 476 and one or more wireless transceivers 478 can be used to communicate data of one or more SIMs 474.

[0105] The computing system 470 may also include (and / or communicate with) one or more non-transitory machine-readable storage media or storage devices (e.g., one or more memory devices 486), which may include, but are not limited to, local and / or network accessible storage, disk drives, drive arrays, optical storage devices, solid-state storage devices (such as RAM and / or ROM), which may be programmable, flash-updatable, and / or the like. Such storage devices may be configured to implement any suitable data storage, including, but not limited to, various file systems, database structures, etc.

[0106] In various aspects, the functionality may be stored as one or more computer program products (e.g., instructions or code) in the memory device 486 and executed by the one or more processors 484 and / or the one or more DSPs 482. The computing system 470 may also include software elements (e.g., located within the one or more memory devices 486) including, for example, an operating system, device drivers, executable libraries, and / or other code, such as one or more applications, which may include a computer program that implements the functionality provided by various aspects, and / or may be designed to implement methods and / or configure systems, as described herein.

[0107] In some aspects, the electronic device 407 may include components for performing the operations described herein. The components may include one or more of the components of the computing system 470. For example, the components for performing the operations described herein may include one or more of the input device 472, the SIM 474, the modem 476, the wireless transceiver 478, the output device 480, the DSP 482, the processor 484, the memory device 486, and / or the antenna 487.

[0108] In some aspects, the electronic device 407 may include components for providing joint communication and sensing and components for sensing RIS by back-reflection coefficient scanning, for example, when multiplexing sensing and communication signals for joint communication and sensing. In some examples, any or all of these components may include one or more wireless transceivers 478, one or more modems 476, one or more processors 484, one or more DSPs 482, one or more memory devices 486, any combination thereof, or other components of the electronic device 407.

[0109] Figure 5 is a diagram illustrating an example of a wireless device 500 utilizing RF single-station sensing techniques for determining one or more characteristics (eg, position, velocity or speed, heading, etc.) of a target 502 object. Specifically, Figure 5 is a diagram illustrating an example of a wireless device 500 (e.g., a transmit / receive sensing node) that utilizes RF sensing technology (e.g., single-station sensing) to perform one or more functions, such as detecting the presence and location of a target 502 (e.g., an object, user, or vehicle), which is illustrated in the figure in the form of a vehicle.

[0110] In some examples, wireless device 500 may be a mobile phone, a tablet computer, a wearable device, a vehicle, an extended reality (XR) device, a computing device or a component of a vehicle, or other device that includes at least one RF interface (e.g., Figure 4 In some examples, the wireless device 500 may be a user device (e.g., Figure 4 An electronic device 407) provides connectivity, such as a base station (e.g., gNB, eNB, etc.), a wireless access point (AP), or other device including at least one RF interface.

[0111] In some aspects, the wireless device 500 may include one or more components for transmitting RF signals. The wireless device 500 may include at least one processor 522 for generating a digital signal or waveform. The wireless device 500 may also include a digital-to-analog converter (DAC) 504 capable of receiving a digital signal or waveform from the processor 522 (e.g., a microprocessor) and converting the digital signal or waveform into an analog waveform. The analog signal as an output of the DAC 504 may be provided to the RF transmitter 506 for transmission. The RF transmitter 506 may be a Wi-Fi transmitter, a 5G / NR transmitter, a Bluetooth transmitter, or a wireless transmitter. TM transmitter or any other transmitter capable of transmitting RF signals.

[0112] The RF transmitter 506 can be coupled to one or more transmit antennas, such as a Tx antenna 512. In some examples, the transmit (Tx) antenna 512 can be an omnidirectional antenna capable of transmitting RF signals in all directions. For example, the Tx antenna 512 can be an omnidirectional Wi-Fi antenna capable of radiating Wi-Fi signals (e.g., 2.4 GHz, 5 GHz, 6 GHz, etc.) in a 360-degree radiation pattern. In another example, the Tx antenna 512 can be a directional antenna that transmits RF signals in a specific direction.

[0113] In some examples, the wireless device 500 may also include one or more components for receiving RF signals. For example, the receiver array in the wireless device 500 may include one or more receiving antennas, such as a receiving (Rx) antenna 514. In some examples, the Rx antenna 514 may be an omnidirectional antenna capable of receiving RF signals from multiple directions. In other examples, the Rx antenna 514 may be a directional antenna configured to receive signals from a specific direction. In another example, the Tx antenna 512 and / or the Rx antenna 514 may include multiple antennas (e.g., elements) configured as an antenna array (e.g., a phased antenna array).

[0114] The wireless device 500 may also include an RF receiver 510 coupled to an Rx antenna 514. The RF receiver 510 may include a signal for receiving RF waveforms (such as Wi-Fi signals, Bluetooth signals, etc.). TM The RF receiver 510 may be configured to receive an analog RF waveform received by the RF receiver 510 and to receive an analog RF waveform received by the RF receiver 510. The ADC 508 may be configured to convert the received analog RF waveform into a digital waveform. The digital waveform as an output of the ADC 508 may be provided to a processor 522 for processing. The processor 522 (e.g., a digital signal processor (DSP)) may be configured to process the digital waveform.

[0115] In one example, the wireless device 500 can implement an RF sensing technique, such as a single-station sensing technique, by having a Tx waveform 516 transmitted from the Tx antenna 512. Although the Tx waveform 516 is illustrated as a single line, in some cases, the Tx waveform 516 can be transmitted in all directions by the omnidirectional Tx antenna 512. In one example, the Tx waveform 516 can be a Wi-Fi waveform transmitted by a Wi-Fi transmitter in the wireless device 500. In some cases, the Tx waveform 516 can correspond to a Wi-Fi waveform transmitted at the same time or nearly at the same time as a Wi-Fi data communication signal or a Wi-Fi control function signal (e.g., a beacon transmission). In some examples, the Tx waveform 516 can be transmitted using the same or similar frequency resources as the Wi-Fi data communication signal or the Wi-Fi control function signal (e.g., a beacon transmission). In some aspects, the Tx waveform 516 can correspond to a Wi-Fi waveform transmitted separately from the Wi-Fi data communication signal and / or the Wi-Fi control signal (e.g., the Tx waveform 516 can be transmitted at a different time and / or using different frequency resources).

[0116] In some examples, Tx waveform 516 may correspond to a 5G NR waveform transmitted simultaneously or nearly simultaneously with a 5G NR data communication signal or a 5G NR control function signal. In some examples, Tx waveform 516 may be transmitted using the same or similar frequency resources as the 5G NR data communication signal or the 5G NR control function signal. In some aspects, Tx waveform 516 may correspond to a 5G NR waveform transmitted separately from the 5G NR data communication signal and / or the 5G NR control signal (e.g., Tx waveform 516 may be transmitted at a different time and / or using different frequency resources).

[0117] In some aspects, one or more parameters associated with the Tx waveform 516 may be modified, which may be used to increase or decrease RF sensing resolution. These parameters may include frequency, bandwidth, number of spatial streams, number of antennas configured to transmit the Tx waveform 516, number of antennas configured to receive reflected RF signals (e.g., Rx waveform 518) corresponding to the Tx waveform 516, number of spatial links (e.g., number of spatial streams multiplied by number of antennas configured to receive RF signals), sampling rate, or any combination thereof. The transmitted waveform (e.g., Tx waveform 516) and the received waveform (e.g., Rx waveform 518) may include one or more RF sensing signals, which are also referred to as radar reference signals (RS).

[0118] In another example, the Tx waveform 516 can be implemented as a sequence with perfect or nearly perfect autocorrelation properties. For example, the Tx waveform 516 can include a single carrier Zadoff sequence or can include symbols similar to orthogonal frequency division multiplexing (OFDM) long training field (LTF) symbols. In some cases, the Tx waveform 516 can include a chirp signal as used, for example, in a frequency modulated continuous wave (FM-CW) radar system. In some configurations, the chirp signal can include a signal in which the signal frequency increases and / or decreases periodically in a linear and / or exponential manner.

[0119] In some aspects, the wireless device 500 can implement RF sensing techniques by performing alternating transmit and receive functions (e.g., performing half-duplex operation). For example, the wireless device 500 can alternatively enable its RF transmitter 506 to transmit a Tx waveform 516 when the RF receiver 510 is not enabled to receive (i.e., not receiving), and enable its RF receiver 510 to receive an Rx waveform 518 when the RF transmitter 506 is not enabled to transmit (i.e., not transmitting). When the wireless device 500 performs half-duplex operation, the wireless device 500 can transmit a Tx waveform 516, which can be a radar RS (e.g., a sensing signal).

[0120] In other aspects, the wireless device 500 can implement RF sensing techniques by performing concurrent transmit and receive functions (e.g., performing sub-band or full-band full-duplex operation). For example, the wireless device 500 can enable its RF receiver 510 to receive at or nearly the same time as it enables its RF transmitter 506 to transmit the Tx waveform 516. When the wireless device 500 performs full-duplex operation (e.g., sub-band full-duplex or full-band full-duplex), the wireless device 500 can transmit the Tx waveform 516, which can be a radar RS (e.g., a sensing signal).

[0121] In some examples, the transmission of a sequence or pattern included in the Tx waveform 516 may be continuously repeated such that the sequence is transmitted a specific number of times or for a specific duration. In some examples, if the RF receiver 510 is enabled after the RF transmitter 506, the repetition of the pattern in the transmission of the Tx waveform 516 may be used to avoid missing the reception of any reflected signals. In one example implementation, the Tx waveform 516 may include a sequence having a sequence length L that is transmitted two or more times, which may allow the RF receiver 510 to be enabled at a time less than or equal to L in order to receive reflections corresponding to the entire sequence without losing any information.

[0122] By implementing alternating or simultaneous transmit and receive functionality (e.g., half-duplex or full-duplex operation), the wireless device 500 can receive a signal corresponding to the Tx waveform 516. For example, the wireless device 500 can receive a signal reflected from an object or person within the range of the Tx waveform 516, such as the Rx waveform 518 reflected from the target 502. The wireless device 500 can also receive a leakage signal (e.g., Tx leakage signal 520) that is directly coupled from the Tx antenna 512 to the Rx antenna 514 without reflecting from any object. For example, the leakage signal may include a signal that is passed from a transmitter antenna (e.g., Tx antenna 512) on the wireless device to a receive antenna (e.g., Rx antenna 514) on the wireless device without reflecting from any object. In some cases, the Rx waveform 518 may include multiple sequences corresponding to multiple copies of the sequence included in the Tx waveform 516. In some examples, the wireless device 500 can combine multiple sequences received by the RF receiver 510 to improve the signal-to-noise ratio (SNR).

[0123] The wireless device 500 may also implement RF sensing techniques by obtaining RF sensing data associated with each of the received signals corresponding to the Tx waveform 516. In some examples, the RF sensing data may include channel state information (CSI) data related to a direct path of the Tx waveform 516 (e.g., the leakage signal 520) and data related to a reflected path corresponding to the Tx waveform 516 (e.g., the Rx waveform 518).

[0124] In some aspects, the RF sensing data (e.g., CSI data) may include information that can be used to determine the manner in which an RF signal (e.g., Tx waveform 516) propagates from the RF transmitter 506 to the RF receiver 510. The RF sensing data may include data corresponding to the effects on the transmitted RF signal due to scattering, fading, and / or power attenuation with distance, or any combination thereof. In some examples, the RF sensing data may include imaginary data and real data (e.g., I / Q components) corresponding to each tone in the frequency domain over a particular bandwidth.

[0125] In some examples, the RF sensing data can be used by the processor 522 to calculate the distance and arrival angle corresponding to the reflected waveform (such as Rx waveform 518). In other examples, the RF sensing data can also be used to detect motion, determine position, detect changes in position or motion patterns, or any combination thereof. In some cases, the distance and arrival angle of the reflected signal can be used to identify the size, position, movement, and / or orientation of a target (e.g., target 502) in the surrounding environment in order to detect target presence / proximity.

[0126] The processor 522 of the wireless device 500 can calculate the distance and arrival angle corresponding to the reflected waveform (e.g., the distance and arrival angle corresponding to the Rx waveform 518) by utilizing signal processing, machine learning algorithms, any other suitable technology, or any combination thereof. In other examples, the wireless device 500 can send or transmit the RF sensing data to at least one processor of another computing device (such as a server or a base station), and the other computing device can perform calculations to obtain the distance and arrival angle corresponding to the Rx waveform 518 or other reflected waveforms.

[0127] In one example, the distance of the Rx waveform 518 may be calculated by measuring the time difference from when the leakage signal is received to when the reflected signal is received. For example, the wireless device 500 may determine a baseline distance zero based on the difference (e.g., propagation delay) from when the wireless device 500 transmits the Tx waveform 516 to when it receives the leakage signal 520. The processor 522 of the wireless device 500 may then determine the distance associated with the Rx waveform 518 based on the difference (e.g., time of flight, also referred to as round trip time (RTT)) from when the wireless device 500 transmits the Tx waveform 516 to when it receives the Rx waveform 518, which may then be adjusted based on the propagation delay associated with the leakage signal 520. In doing so, the processor 522 of the wireless device 500 may determine the distance traveled by the Rx waveform 518, which may be used to determine the presence and movement of an object (e.g., object 502) causing the reflection.

[0128] In another example, the angle of arrival of the Rx waveform 518 may be calculated by the processor 522 by measuring the arrival time difference of the Rx waveform 518 between individual elements of the receive antenna array, such as the antenna 514. In some examples, the arrival time difference may be calculated by measuring the receive phase difference at each element in the receive antenna array.

[0129] In some cases, the distance and angle of arrival of the Rx waveform 518 may be used by the processor 522 to determine the distance between the wireless device 500 and the target 502 and the position of the target 502 relative to the wireless device 500. The distance and angle of arrival of the Rx waveform 518 may also be used to determine the presence, movement, proximity, identity, or any combination thereof of the target 502. For example, the processor 522 of the wireless device 500 may utilize the calculated distance and angle of arrival corresponding to the Rx waveform 518 to determine that the target 502 is moving toward the wireless device 500.

[0130] As mentioned above, the wireless device 500 may include a mobile device (e.g., an IoT device, a smart phone, a laptop, a tablet, etc.) or other types of devices. In some examples, the wireless device 500 may be configured to obtain device location data and device orientation data as well as RF sensing data. In some instances, the device location data and device orientation data may be used to determine or adjust the distance and angle of arrival of a reflected signal (such as Rx waveform 518). For example, when a target 502 (e.g., a vehicle) moves toward the wireless device 500 during the RF sensing process, the wireless device may be set on the ground facing the sky. In this instance, the wireless device 500 may use its location data and orientation data as well as the RF sensing data to determine the direction in which the target 502 is moving.

[0131] In some examples, the wireless device 500 can collect device location data using techniques including RTT measurements, time of arrival (TOA) measurements, time difference of arrival (TDOA) measurements, passive positioning measurements, angle of arrival (AOA) measurements, angle of departure (AoD) measurements, received signal strength indicator (RSSI) measurements, CSI data, using any other suitable techniques, or any combination thereof. In further examples, device orientation data can be obtained from electronic sensors on the wireless device 500, such as a gyroscope, accelerometer, compass, magnetometer, barometer, any other suitable sensor, or any combination thereof.

[0132] Figure 6 6 is a diagram illustrating an example of a receiver 604 utilizing RF monostatic sensing techniques with a transmitter 600 for determining one or more characteristics (e.g., position, velocity or speed, heading, etc.) of a target 602 object. For example, the receiver 604 may use RF bistatic sensing to detect the presence and position of a target 602 (e.g., an object, user, or vehicle) that is located at a certain location. Figure 6 In one example, the receiver 604 may be in the form of a base station such as a gNB.

[0133] Figure 6 The bistatic radar system of includes a transmitter 600 (e.g., a transmitting sensing node), which is depicted in the figure as being in the form of a base station (e.g., a gNB), and a receiver 604 (e.g., a receiving sensing node), which are separated by a distance comparable to the expected target distance. Figure 5 Compared with the single-station system, Figure 6 The transmitter 600 and the receiver 604 of the bistatic radar system are located far from each other. In contrast, a monostatic radar is a radar system that includes transmitters (e.g., Figure 5 RF transmitter 506 of the wireless device 500) and receiver (e.g., Figure 5The RF receiver 510 of the wireless device 500) is a radar system (e.g., Figure 5 system).

[0134] An advantage of a bistatic radar (or more generally, a multistatic radar with more than one receiver) over a monostatic radar is the ability to collect radar echoes reflected from a scene at angles different than the angle at which the pulse was transmitted. This may be of interest in some applications (e.g., vehicle applications, scenes with multiple objects, military applications, etc.) where targets may reflect transmitted energy in many directions (e.g., where targets are specifically designed to reflect in many directions), which may minimize the energy reflected back to the transmitter. It should be noted that in one or more examples, a monostatic system may coexist with a multistatic radar system, such as when the transmitter also has a co-located receiver.

[0135] In some examples, Figure 6 The transmitter 600 and / or the receiver 604 may be a mobile phone, a tablet computer, a wearable device, a vehicle, or other device including at least one RF interface (e.g., Figure 4 In some examples, the transmitter 600 and / or the receiver 604 may be a user device (e.g., Figure 4 IoT device 407) provides connectivity to the device, such as a base station (e.g., gNB, eNB, etc.), a wireless access point (AP), or other device including at least one RF interface.

[0136] In some aspects, the transmitter 600 may include one or more components for transmitting RF signals. The transmitter 600 may include at least one processor (e.g., Figure 5 The transmitter 600 may also include an RF transmitter (e.g., Figure 5 The RF transmitter 506 may be a transmitter configured to transmit a cellular or telecommunication signal (e.g., a transmitter configured to transmit a 5G / NR signal, a 4G / LTE signal, or other cellular / telecommunication signal, etc.), a Wi-Fi transmitter, a Bluetooth transmitter, or a wireless transmitter. TM transmitter, any combination thereof, or any other transmitter capable of transmitting RF signals.

[0137] The RF transmitter may be coupled to one or more transmit antennas, such as a Tx antenna (e.g., Figure 5TX antenna 512). In some examples, the Tx antenna may be an omnidirectional antenna capable of transmitting RF signals in all directions, or a directional antenna capable of transmitting RF signals in a specific direction. In some examples, the Tx antenna may include multiple antennas (e.g., elements) configured as an antenna array.

[0138] The receiver 604 may also include one or more components for receiving RF signals. For example, the receiver 604 may include one or more receiving antennas, such as an Rx antenna (e.g., Figure 5 In some examples, the Rx antenna may be an omnidirectional antenna capable of receiving RF signals from multiple directions, or a directional antenna configured to receive signals from a specific direction. In another example, the Rx antenna may include multiple antennas (e.g., elements) configured as an antenna array.

[0139] The receiver 604 may also include an RF receiver (eg, Figure 5 The RF receiver may include a RF receiver 510 for receiving RF waveforms (such as Wi-Fi signals, Bluetooth TM The output of the RF receiver may be coupled to at least one processor (e.g., Figure 5 The processor may be configured to process the received waveform (eg, Rx waveform 618).

[0140] In one or more examples, the transmitter 600 can implement an RF sensing technique (e.g., a bistatic sensing technique) by transmitting a Tx waveform 616 from a Tx antenna. It should be noted that although the Tx waveform 616 is illustrated as a single line, in some cases, the Tx waveform 616 can be transmitted in all directions by an omnidirectional Tx antenna.

[0141] In one or more aspects, one or more parameters associated with the Tx waveform 616 can be used to increase or decrease the RF sensing resolution. These parameters can include frequency, bandwidth, number of spatial streams, number of antennas configured to transmit the Tx waveform 616, number of antennas configured to receive reflected RF signals (e.g., Rx waveform 618) corresponding to the Tx waveform 616, number of spatial links (e.g., number of spatial streams multiplied by number of antennas configured to receive RF signals), sampling rate, or any combination thereof. The transmitted waveform (e.g., Tx waveform 616) and the received waveform (e.g., Rx waveform 618) can include one or more radar RF sensing signals (also referred to as RF sensing RS).

[0142] During operation, the receiver 604 (e.g., operating as a receive sensing node) can receive a signal corresponding to the Tx waveform 616, which is transmitted by the transmitter 600 (e.g., operating as a transmit sensing node). For example, the receiver 604 can receive a signal reflected from an object or person within the range of the Tx waveform 616, such as the Rx waveform 618 reflected from the target 602. In some cases, the Rx waveform 618 can include multiple sequences corresponding to multiple copies of the sequence included in the Tx waveform 616. In some examples, the receiver 604 can combine the received multiple sequences to improve the SNR.

[0143] In some examples, at least one processor within receiver 604 can use the RF sensing data to calculate a distance, angle of arrival, or other characteristics corresponding to a reflected waveform, such as Rx waveform 618. In other examples, the RF sensing data can also be used to detect motion, determine position, detect a change in position or motion pattern, or any combination thereof. In some cases, the distance and angle of arrival of the reflected signal can be used to identify the size, position, movement, and / or orientation of an object (e.g., object 602) in the surrounding environment in order to detect object presence / proximity.

[0144] The processor of the receiver 604 may calculate the distance and angle of arrival corresponding to the reflected waveform (e.g., the distance and angle of arrival corresponding to the Rx waveform 618) by using signal processing, machine learning algorithms, any other suitable techniques, or any combination thereof. In other examples, the receiver 604 may send or transmit the RF sensing data to at least one processor of another computing device (such as a server), which may perform calculations to obtain the distance and angle of arrival corresponding to the Rx waveform 618 or other reflected waveforms.

[0145] In one or more examples, the angle of arrival of the Rx waveform 618 can be calculated by the processor of the receiver 604 by measuring the time difference of arrival of the Rx waveform 618 between individual elements of the receive antenna array of the receiver 604. In some examples, the time difference of arrival can be calculated by measuring the receive phase difference at each element in the receive antenna array.

[0146] In some cases, the distance and angle of arrival of the Rx waveform 618 may be used by the processor of the receiver 604 to determine the distance between the receiver 604 and the target 602 and the position of the target 602 relative to the receiver 604. The distance and angle of arrival of the Rx waveform 618 may also be used to determine the presence, movement, proximity, identity, or any combination thereof of the target 602. For example, the processor of the receiver 604 may use the calculated distance and angle of arrival corresponding to the Rx waveform 618 to determine that the target 602 is moving toward the receiver 604.

[0147] Figure 7 700a, 700b, and 700c, which can be used to determine one or more characteristics (e.g., position, speed or velocity, heading, etc.) of a target 702 object. For example, receiver 704 can use RF bistatic sensing to detect the presence and location of target 702 (e.g., an object, user, or vehicle). Target 702 is a transmitter (e.g., transmitter 700a, transmitter 700b, and transmitter 700c) that utilizes RF bistatic sensing technology. Figure 7 The objects without communication capabilities (which may be referred to as device-less objects) are depicted in the form of people, vehicles (e.g., vehicles without the ability to send and receive messages such as using C-V2X or DSRC protocols), or other device-less objects. Figure 7 The bistatic radar system is similar to Figure 6 The dual-station radar system is just Figure 7 The bistatic radar system has multiple transmitters 700a, 700b, 700c, and Figure 6 The bistatic radar system has only one transmitter 600 .

[0148] Figure 7 The bistatic radar system of includes a plurality of transmitters 700a, 700b, 700c (eg, transmitting sensing nodes), which are illustrated as being in the form of base stations. Figure 7 The bistatic radar system of also includes a receiver 704 (eg, a receiving sensing node) depicted in the form of a smartphone. Each of the transmitters 700a, 700b, 700c is separated from the receiver 704 by a distance comparable to the expected distance to the target 702. Similar to Figure 6 The dual station system Figure 7 The transmitters 700a, 700b, 700c and the receiver 704 of the bistatic radar system are located far away from each other.

[0149] In one or more examples, the transmitters 700a, 700b, 700c, and / or the receiver 704 can each be a mobile phone, a tablet computer, a wearable device, a vehicle (e.g., a vehicle configured to send and receive communications according to C-V2X, DSRC, or other communication protocols), or other devices including at least one RF interface (e.g., Figure 4 In some examples, transmitters 700a, 700b, 700c and / or receiver 704 may each be a user device (e.g., Figure 4 IoT device 407) provides connectivity to the device, such as a base station (e.g., gNB, eNB, etc.), a wireless access point (AP), or other device including at least one RF interface.

[0150] The transmitters 700a, 700b, 700c may include one or more components for transmitting RF signals. Each of the transmitters 700a, 700b, 700c may include at least one processor (e.g., Figure 5 Each of the transmitters 700a, 700b, 700c may also include an RF transmitter (e.g., Figure 5 RF transmitter 506). In one or more examples, Tx waveforms 716a, 716b, 716c are RF sensing signals, and Tx waveforms 720a, 720b, 720c are communication signals. In one or more examples, Tx waveforms 720a, 720b, 720c are communication signals that can be used to schedule a transmitter (e.g., transmitters 700a, 700b, 700c) and a receiver (e.g., receiver 704) to perform RF sensing of a target (e.g., target 702) to obtain location information about the target. The RF transmitter can be a transmitter configured to transmit a cellular or telecommunication signal (e.g., a transmitter configured to transmit a 5G / NR signal, a 4G / LTE signal, or other cellular / telecom signal, etc.), a Wi-Fi transmitter, a Bluetooth transmitter, or a wireless transmitter. TM transmitter, any combination thereof, or any other transmitter capable of transmitting RF signals.

[0151] The RF transmitter may be coupled to one or more transmit antennas, such as a Tx antenna (e.g., Figure 5 TX antenna 512). In one or more examples, the Tx antenna may be an omnidirectional antenna capable of transmitting RF signals in all directions, or a directional antenna that transmits RF signals in a specific direction. The Tx antenna may include multiple antennas (e.g., elements) configured as an antenna array.

[0152] Figure 7 The receiver 704 may include one or more components for receiving RF signals. For example, the receiver 704 may include one or more receiving antennas, such as Rx antennas (e.g., Figure 5 In one or more examples, the Rx antenna can be an omnidirectional antenna capable of receiving RF signals from multiple directions, or a directional antenna configured to receive signals from a specific direction. In some examples, the Rx antenna can include multiple antennas (e.g., elements) configured as an antenna array (e.g., a phased antenna array).

[0153] The receiver 704 may also include an RF receiver (eg, Figure 5The RF receiver may include a RF receiver 510 for receiving RF waveforms (such as Wi-Fi signals, Bluetooth TM The output of the RF receiver may be coupled to at least one processor (e.g., Figure 5 The processor 522 may be configured to process the received waveform (eg, Rx waveform 718, which is the reflected (echo) RF sensing signal).

[0154] In some examples, the transmitters 700a, 700b, 700c can implement RF sensing techniques (e.g., bistatic sensing techniques) by having Tx waveforms 716a, 716b, 716c (e.g., radar sensing signals) transmitted from a Tx antenna associated with each of the transmitters 700a, 700b, 700c. Although the Tx waveforms 716a, 716b, 716c are illustrated as a single line, in some cases, the Tx waveforms 716a, 716b, 716c can be transmitted in all directions (e.g., through an omnidirectional Tx antenna associated with each of the transmitters 700a, 700b, 700c).

[0155] In one or more aspects, one or more parameters associated with the Tx waveforms 716a, 716b, 716c can be used to increase or decrease RF sensing resolution. These parameters can include, but are not limited to, frequency, bandwidth, number of spatial streams, number of antennas configured to transmit the Tx waveforms 716a, 716b, 716c, number of antennas configured to receive reflected (echo) RF signals (e.g., Rx waveform 718) corresponding to each of the Tx waveforms 716a, 716b, 716c, number of spatial links (e.g., number of spatial streams multiplied by number of antennas configured to receive RF signals), sampling rate, or any combination thereof. The transmitted waveforms (e.g., Tx waveforms 716a, 716b, 716c) and the received waveforms (e.g., Rx waveform 718) can include one or more radar RF sensing signals (also referred to as RF sensing RS). It should be noted that although in Figure 7 Only one reflected sensing signal (eg, Rx waveform 718 ) is shown in , but it should be understood that a separate reflected (echo) sensing signal will be generated by each sensing signal reflected from the target 702 (eg, Tx waveforms 716 a , 716 b , 716 c ).

[0156] exist Figure 7During operation of the system, the receiver 704 (e.g., which operates as a receive sensing node) can receive signals corresponding to Tx waveforms 716a, 716b, 716c transmitted by transmitters 700a, 700b, 700c (e.g., which each operate as a transmit sensing node). The receiver 704 can receive signals reflected from objects or people within the range of the Tx waveforms 716a, 716b, 716c, such as the Rx waveform 718 reflected from the target 702. In one or more examples, the Rx waveform 718 can include multiple sequences corresponding to multiple copies of the sequence included in its corresponding Tx waveform 716a, 716b, 716c. In some examples, the receiver 704 can combine the received multiple sequences to improve the SNR.

[0157] In some examples, the RF sensing data can be used by at least one processor within the receiver 704 to calculate the distance, angle of arrival (AOA), TDOA, angle of departure (AoD), or other characteristics corresponding to the reflected waveform (e.g., Rx waveform 718). In other examples, the RF sensing data can also be used to detect motion, determine position, detect changes in position or motion patterns, or any combination thereof. In one or more examples, the distance and angle of arrival of the reflected signal can be used to identify the size, position, movement, and / or orientation of the target (e.g., target 702) in order to detect target presence / proximity.

[0158] The processor of the receiver 704 can calculate the distance and arrival angle corresponding to the reflected waveform (e.g., the distance and arrival angle corresponding to the Rx waveform 718) by using signal processing, machine learning algorithms, any other suitable techniques, or any combination thereof. In one or more examples, the receiver 704 can send or transmit the RF sensing data to at least one processor of another computing device (such as a server), which can perform calculations to obtain the distance and arrival angle corresponding to the Rx waveform 718 or other reflected waveforms (not shown).

[0159] In one or more examples, the processor of the receiver 704 can calculate the angle of arrival (AOA) of the Rx waveform 718 by measuring the TDOA of the Rx waveform 718 between the various elements of the receive antenna array of the receiver 704. In some examples, the TDOA can be calculated by measuring the receive phase difference at each element in the receive antenna array. In an illustrative example, to determine the TDOA, the processor can determine the arrival time difference of the Rx waveform 718 to the receive antenna array element using one of the receive antenna array elements as a reference. The time difference is proportional to the distance difference.

[0160] In some cases, the processor of the receiver 704 may use the distance, AOA, TDOA, other measurement information (e.g., AoD, etc.), any combination thereof of the Rx waveform 718 to determine the distance between the receiver 704 and the target 702, and determine the position of the target 702 relative to the receiver 704. In one example, the processor may use the distance, AOA, and / or TDOA information as input to apply multilateration or other location-based algorithms to determine the position (e.g., 3D position) of the target 702. In other examples, the processor may use the distance, AOA, and / or TDOA of the Rx waveform 718 to determine the presence, movement (e.g., speed or velocity, heading or direction or movement, etc.), proximity, identity, any combination thereof, or other characteristics of the target 702. For example, the processor of the receiver 704 may use the distance, AOA, and / or TDOA corresponding to the Rx waveform 718 to determine that the target is moving toward the receiver 704.

[0161] Figure 8 is a diagram illustrating the geometry for bistatic (or monostatic) sensing. Figure 8 The bistatic radar north reference coordinate system in two dimensions is shown. Specifically, Figure 8 800, receiver 804, and target 802 are shown. The bistatic triangle is located in the bistatic plane. The transmitter 800, target 802, and receiver 804 are shown relative to each other. The transmitter 800 and receiver 804 are separated by a baseline distance L. An extended baseline is defined such that the baseline distance L extends beyond the transmitter 800 or the receiver 804. The target 802 and the transmitter 800 are separated by a distance RT, and the target 802 and the receiver 804 are separated by a distance RR.

[0162] Angle θ T and θ R are the transmitter 800 observation angle and the receiver 804 observation angle, respectively, which are considered positive when measured clockwise from North (N). Angle θ T and θ R Also known as the angle of arrival (AOA) or line of sight (LOS). The bistatic angle (β) is the angle between the transmitter 800, the target 802, and the receiver 804 in the radar. Specifically, the bistatic angle is the angle between the transmitter 800 and the receiver 804, with the vertex at the target 802. The bistatic angle is equal to the observation angle of the transmitter 800 minus the observation angle of the receiver 804 θ R (For example, β = θ T -θ R ).

[0163] When the bistatic angle is exactly zero (0°), the radar is considered to be monostatic; when the bistatic angle is close to zero, the radar is considered to be pseudo-monostatic; and when the bistatic angle is close to 180 degrees, the radar is considered to be a forward scatter radar. Otherwise, the radar is simply considered and is called a bistatic radar. The bistatic angle (β) can be used to determine the radar cross section of the target.

[0164] Fig. 9 9 is a diagram illustrating an example of a bistatic range 910 for bistatic sensing. In the diagram, a transmitter (Tx) 900, a target 902, and a receiver (Rx) 904 of a radar are shown relative to each other. The transmitter 900 is separated from the receiver 904 by a baseline distance L, the target 902 is separated from the transmitter 900 by a distance Rtx, and the target 902 is separated from the receiver 904 by a distance Rrx.

[0165] Bistatic range 910 (shown as an ellipse) refers to a measured range made by a radar having a separate transmitter 900 and receiver 904 (e.g., the transmitter 900 and receiver 904 are positioned far from each other). Receiver 904 measures the arrival time from when transmitter 900 transmits a signal to when receiver 904 receives the signal from transmitter 900 via target 902. Bistatic range 910 defines an ellipse of constant bistatic distance, referred to as an equidistant profile, on which target 902 is located, with the focus centered on transmitter 900 and receiver 904. If target 902 is at a distance Rrx from receiver 904 and a distance Rtx from transmitter 900, and receiver 904 and transmitter 900 are at a distance L from each other, then the bistatic range is equal to Rrx+Rtx-L. It should be noted that the motion of target 902 causes a rate of change in the bistatic range, which results in a bistatic Doppler shift.

[0166] Typically, the constant bistatic distance points draw ellipses with the transmitter 900 and receiver 904 positioned as foci. The bistatic isostatic contours are where the ground slices through the ellipse. When the ground is flat, the intercepts form ellipses (e.g., bistatic distance 910). Note that these ellipses are not centered on the mirror point except when the two platforms have equal heights.

[0167] As mentioned previously, RIS (e.g., Fig. 10A RIS 1030) can be employed for sensing and / or communication. RIS has traditionally been used for communication, however RIS can also be employed to assist in sensing of the ISAC system. RIS-assisted sensing requires a higher accuracy (e.g., higher precision) of RIS location than RIS-assisted communication requires.

[0168] Fig. 10A is a diagram illustrating an example of a system 1000 for performing RIS-assisted communications. Fig. 10A, system 1000 is shown to include a network device 1020 in the form of a UE that can operate as a communication receiver. Also shown is a network device 1010 in the form of a base station (e.g., a gNB or a portion of a gNB such as a CU, DU, RU, near-RT RIC, non-RT RIC, etc.) that can operate as a communication transmitter. System 1000 also includes a RIS 1030. In some cases, an obstacle 1040 (e.g., in the form of a building) may be blocking the line of sight (LOS) from the network device 1010 (e.g., gNB) to the network device 1020 (e.g., UE).

[0169] System 1000 may include, for example Fig. 10A In addition, the system 1000 may include more or fewer network devices as shown. Fig. 10A Different types of network devices (e.g., vehicles) are shown. In one or more examples, network devices 1020 (e.g., UE) and 1010 (e.g., gNB) can be equipped with heterogeneous capabilities, which can include but are not limited to 4G / 5G cellular connectivity, GPS capabilities, camera capabilities, radar capabilities, and / or LIDAR capabilities. Network devices 1020, 1010 can be capable of performing wireless communications with each other via communication signals (e.g., signals 1050a, 1050b).

[0170] RIS 1030 may passively operate as a relay device by reflecting a signal (e.g., a communication signal) radiated from another network device (e.g., a network device 1010 in the form of a gNB) in a direction toward one network device (e.g., a network device 1020 in the form of a UE). For example, during operation of system 1000 for RIS-assisted communication, due to the presence of obstacle 1040 (e.g., a building) located within the LOS between network device 1010 (e.g., a gNB) and network device 1020 (e.g., a UE), network device 1010 (e.g., a gNB) may send a communication signal (e.g., signal 1050a) toward RIS 1030. The communication signal (e.g., signal 1050a) may be reflected from RIS 1030 to generate a reflected communication signal (e.g., signal 1050b). Elements of RIS 1030 may cause the reflected communication signal (eg, signal 1050b) to be radiated in a direction toward network device 1020 (eg, UE), which may then receive the reflected communication signal (eg, signal 1050b).

[0171] Fig. 10B is a diagram illustrating an example of a system 1005 for performing RIS-assisted sensing. Fig. 10B, system 1005 is shown to include a network device 1015 in the form of a base station (e.g., a gNB or a portion of a gNB such as a CU, DU, RU, near-RT RIC, non-RT RIC, etc.). Network device 1015 (e.g., gNB) can operate as a radar transmitter (Tx) and / or a radar receiver (Rx) for sensing purposes (e.g., for monostatic or bistatic sensing of a target such as target 1080). System 1005 also includes RIS 1035. There may also be an obstacle 1045 (e.g., in the form of a building) that is blocking the LOS from network device 1015 (e.g., gNB) to target 1080, which is shown in the form of a vehicle.

[0172] System 1005 may include, for example Fig. 10B In addition, the system 1005 may include more or fewer network devices as shown. Fig. 10B Different types of network devices (e.g., mobile phones and / or vehicles) are shown. In one or more examples, network device 1015 (e.g., gNB) can be equipped with heterogeneous capabilities, which can include but are not limited to 4G / 5G cellular connectivity, GPS capabilities, camera capabilities, radar capabilities, and / or LIDAR capabilities. Network device 1015 (e.g., gNB) can be capable of performing wireless communications with other network devices via communication signals.

[0173] In one or more examples, the network device 1015 (e.g., gNB) may be capable of sending and receiving some type of sensing signal (e.g., camera, RF sensing signal, optical sensing signal, etc.). In some cases, the network device 1015 (e.g., gNB) may send and receive sensing signals (e.g., RF sensing signals 1060a, 1070b) for detecting nearby targets (e.g., target 1080 in the form of a vehicle) using one or more sensors. In some cases, the network device 1015 (e.g., gNB) may detect nearby targets based on one or more images or frames captured using one or more cameras.

[0174] The network device 1015 (e.g., a gNB) that can operate as a radar Tx and / or a radar Rx can perform RF sensing (e.g., bistatic sensing or monostatic sensing) of at least one target (e.g., target 1080) to obtain RF sensing measurements (e.g., Doppler measurements, RTT measurements, TOA measurements, and / or TDOA measurements) of the target (e.g., target 1080). The RF sensing measurements of the target (e.g., target 1080) can be used (e.g., by at least one processor of the network device 1015) to determine one or more characteristics (e.g., velocity, location, distance, movement, heading, size, and / or other characteristics) of the target (e.g., target 1080).

[0175] RIS 1035 can passively operate as a relay device by reflecting a signal (e.g., a sensing signal) radiated from a network device (e.g., a network device 1015 in the form of a gNB) in a direction toward a target (e.g., a target 1080 in the form of a vehicle). RIS 1035 can also passively operate as a relay device by reflecting a signal (e.g., a reflected sensing signal) from a target (e.g., a target 1080) in a direction toward a network device (e.g., a network device 1015).

[0176] For example, during operation of the system 1005 for RIS-assisted sensing, such as when performing single-station sensing of a target (e.g., target 1080), due to the presence of an obstacle 1045 (e.g., a building) located within the LOS between the network device 1015 (e.g., a gNB) and the target 1080 (e.g., a vehicle), the network device 1015 (e.g., a gNB) operating as a radar Tx can send an RF sensing signal 1060a toward the RIS 1035. The RF sensing signal 1060a can be included in the communication signal and the sensing signal that are multiplexed together (e.g., via time division multiplexing and / or frequency division multiplexing) for joint communication and sensing purposes. The sensing signal 1060a can be reflected from the RIS 1035 to produce a reflected sensing signal (e.g., signal 1060b). Elements of the RIS 1035 can cause the reflected sensing signal (e.g., signal 1060b) to be radiated in a direction toward the target 1080.

[0177] The sensing signal 1060b may be reflected from the target 1080 to generate an RF reflected sensing signal 1070a, which may be reflected back toward the RIS 1035. The sensing signal 1070a may be reflected from the RIS 1035 to generate a reflected sensing signal (e.g., signal 1070b). Elements of the RIS 1035 may cause the reflected sensing signal (e.g., signal 1070b) to be radiated in a direction toward the network device 1015 (e.g., gNB).

[0178] The network device 1015 (e.g., gNB) operating as a radar Rx may receive the reflection sensing signal 1070b. After the network device 1015 (e.g., gNB) receives the reflection sensing signal 1070b, the network device 1015 (e.g., gNB) may obtain a measurement (e.g., Doppler measurement, RTT measurement, TOA measurement, and / or TDOA measurement) of the reflection sensing signal 1070b. At least one processor (e.g., Fig. 20The processor 2010) can then determine or calculate characteristics of the target 1080 (e.g., speed, position, distance, movement, heading, size, etc.) by using sensing measurements (e.g., Doppler measurements, RTT measurements, TOA measurements, and / or TDOA measurements) from the received reflected sensing signal 1070b.

[0179] Fig.11A is a diagram illustrating an example of a RIS 1100 that may be employed by the disclosed systems and techniques for sensing RIS by back-tracing reflection coefficient scanning. As previously mentioned, the RIS may shape the wireless environment into a desired form at low cost. In practice, the RIS has three types of specific implementations, including reflection (e.g., where a signal may be reflected by the RIS), transmission (e.g., where a signal may penetrate the RIS), and hybrid (e.g., where the RIS may have dual functions of reflection and transmission).

[0180] A RIS (e.g., RIS1100) is a programmable array structure that can be used to control the propagation of electromagnetic (EM) waves (e.g., steer an RF beam) by changing the electrical and magnetic properties of the surface of the RIS (e.g., RIS1100). Fig.11A In the embodiment of the present invention, RIS 1100 includes an array of metamaterial RIS elements 1110, which are composed of an ultra-thin surface with embedded multiple wavelength scatterers. The electromagnetic properties of RIS elements 1110 can be dynamically controlled by applying control signals to tunable elements (e.g., Pin diodes, varactor diodes, and / or other tunable elements) on RIS elements 1110, which can enable active and intelligent modulation of electromagnetic waves in a programmable manner to form an electromagnetic field with controllable amplitude, phase, polarization, and / or frequency. For example, the electromagnetic response of RIS elements 1110 (e.g., steering the phase shift of an RF beam) can be controlled by a programmable Pin diode.

[0181] RIS 1100 may passively operate as a relay device by reflecting a signal (e.g., signal 1120a). A signal (e.g., signal 1120a) may be transmitted from a network device (e.g., a gNB or a UE) toward RIS 1100 at an incident angle θ. i A signal (eg, signal 1120a) may be reflected from RIS 1110 to generate a reflected signal (eg, signal 1120b), which may be reflected at a reflection angle θ. r The RIS element 1110 may cause a reflected signal (eg, signal 1120b) to be radiated in a specific direction (eg, in a direction toward a target object).

[0182] for Fig.11A, it can be assumed that the network device (e.g., gNB) and the target object are both located in the far field of the surface of RIS1100. When a signal (e.g., signal 1120a) is incident at an angle θ i When transmitting toward RIS1100, the nth element of RIS1100 is at an incident angle θ i and the reflection angle θ r The equivalent channel response value is:

[0183]

[0184] in is the reflection coefficient of the element, d n is the distance from the nth element to the 1st element, and λ is the wavelength.

[0185] All of the RIS elements 1110 are at an incident angle θ i and the reflection angle θ r The overall equivalent channel response value under is:

[0186]

[0187] Theoretically, if the reflection coefficient satisfies:

[0188]

[0189] The reflected beam can then point in the direction θ r

[0190] In practice, the coefficient amplitudes and phase values ​​for each parent element (eg, RIS element 1110) can only come from a finite set {(a1, φ1), (a2, φ2), ..., (a M ,φ M )}. Therefore, the actual beam shape may have a certain deviation from the ideal beam shape. The larger the number of RIS elements 1110, the closer the actual beam shape will be to the ideal beam shape, and the more accurate the beam direction will be.

[0191] Fig. 11B This is an example for Fig.11A Table 1105 of example phase shift 1140 and amplitude responses 1150 for different configurations 1130 of the RIS 1100. Specifically, Fig. 11B , the corresponding phase shift 1140 and amplitude response 1150 (e.g., amplitude or channel response) for each of four different example configurations 1130 (e.g., configurations 1, 2, 3, and 4) of the RIS 1100 are shown in Table 1105. In some aspects, the channel response h (or in some cases, h) that is closest to the determined channel response h is the channel response that is closest to the determined channel response h. n )'s configuration is determined for the RIS1100.

[0192] As previously mentioned, RIS has traditionally been used for communications, however RIS may also be employed to assist in sensing (e.g., of an ISAC system). RIS-assisted sensing may require the RIS location to be determined with higher accuracy than that used for RIS-assisted communications. Traditional sensing (e.g., without the use of RIS) may present many challenges, which may include: limited coverage distance due to return transmissions, coverage holes when there is no LOS link between a network device (e.g., a gNB or UE) and a target, and / or an insufficient number of positioning reference points because one network device (e.g., a gNB or UE) can only provide one reference point. RIS-based sensing (e.g., using RIS for sensing) may provide many benefits, which may include: extending coverage distance by using RIS beamforming, eliminating coverage holes by operating the RIS as a relay device, and / or using the location of the RIS as an additional reference point.

[0193] In order to realize the benefits of RIS-based sensing, the network device (e.g., gNB or UE) should know the location of the RIS. For example, during operation of the disclosed system, if the location of the RIS is unknown (e.g., the RIS does not have GPS capability or the GPS signal is blocked), the network device (e.g., gNB or UE) should first estimate the location of the RIS before using the RIS to assist in sensing. After the network device (e.g., gNB or UE) obtains the location of the RIS, the network device (e.g., gNB or UE) can determine the specific beam radiated from the RIS and can use the location of the RIS as a reference point for sensing. Solutions for sensing the RIS and estimating the location of the RIS are provided herein. These solutions involve sensing the RIS by employing retro-reflection coefficient scanning.

[0194] Fig.12 1 is a diagram illustrating an example of a system 1200 for sensing a RIS 1230 by using a retroreflection coefficient. Fig.12, system 1200 is shown to include network devices 1210a, 1210b in the form of a base station (e.g., a gNB or a portion of a gNB, such as a CU, DU, RU, near-RT RIC, non-RT RIC, etc.). Network devices 1210a, 1210b (e.g., gNB) can each operate as a radar Tx and / or radar Rx for sensing purposes (e.g., for single-station or dual-station sensing). System 1200 also includes network devices 1220a, 1220b in the form of a UE (e.g., a mobile phone (e.g., a smart phone)). Network devices 1220a, 1220b (e.g., UE) can each operate as a radar Tx and / or radar Rx for sensing purposes (e.g., for single-station or dual-station sensing). System 1200 additionally includes RIS 1230.

[0195] System 1200 may include, for example Fig.12 In addition, the system 1200 may include more or fewer network devices as shown. Fig.12 Different types of network devices (e.g., vehicles) are shown. In one or more examples, network devices 1210a, 1210b, 1220a, 1220b can be equipped with heterogeneous capabilities, which can include, but are not limited to, 4G / 5G cellular connectivity, GPS capabilities, camera capabilities, radar capabilities, and / or LIDAR capabilities. Network devices 1210a, 1210b, 1220a, 1220b can be capable of performing wireless communications with other network devices via communication signals.

[0196] In one or more examples, the network devices 1210a, 1210b, 1220a, 1220b may be capable of sending and receiving some type of sensing signal (e.g., camera, RF sensing signal, optical sensing signal, etc.). In some cases, the network devices 1210a, 1210b, 1220a, 1220b may send and receive sensing signals (e.g., RF sensing signals 1060a, 1070b) for detecting the RIS 1230 (and / or target) using one or more sensors. In some cases, the network devices 1210a, 1210b, 1220a, 1220b may detect the RIS 1230 (and / or target) by using one or more images or frames captured using one or more cameras.

[0197] The network devices 1210a, 1210b, 1220a, 1220b, which may each operate as a radar Tx and a radar Rx, may perform RF sensing (e.g., single-station sensing) of the RIS 1230 to obtain RF sensing measurements (e.g., Doppler measurements, RTT measurements, TOA measurements, and / or TDOA measurements) of the RIS 1230. The RF sensing measurements of the RIS 1230 may be used (e.g., by at least one processor of the network devices 1210a, 1210b, 1220a, 1220b) to determine one or more characteristics (e.g., location) of the RIS 1230.

[0198] RIS 1230 can passively operate as a relay device by reflecting signals radiated from network devices 1210a, 1210b, 1220a, 1220b (e.g., sensing signals) in the opposite direction back toward network devices 1210a, 1210b, 1220a, 1220b. Network devices 1210a, 1210b, 1220a, 1220b can each sense RIS 1230 by using single-station sensing, and RIS 1230 can reflect the reflected sensing signals (e.g., signals 1240b, 1250b) in the correct direction back toward network devices 1210a, 1210b, 1220a, 1220b by using a back-reflection coefficient.

[0199] For example, during operation of the system 1200, such as when performing single-station sensing of the RIS 1230, a network device operating as a radar Tx (e.g., network device 1210a or 1220a) may transmit an RF sensing signal 1240a toward the RIS 1230. The RF sensing signal 1240a may be included in a communication signal and a sensing signal that are multiplexed together (e.g., via time division multiplexing and / or frequency division multiplexing) for joint communication and sensing purposes. The sensing signal 1240a may be reflected from the RIS 1230 to produce a reflected sensing signal (e.g., signal 1240b). Elements of the RIS 1230 (e.g., by using a back reflection coefficient) may cause the reflected sensing signal (e.g., signal 1240b) to be radiated in a direction back toward the network device (e.g., network device 1210a or 1220a).

[0200] A network device (e.g., network device 1210a or 1220a) operating as a radar Rx may receive a reflection sensing signal 1240b. After the network device (e.g., network device 1210a or 1220a) receives the reflection sensing signal 1240b, the network device (e.g., network device 1210a or 1220a) may obtain a measurement (e.g., Doppler measurement, RTT measurement, TOA measurement, and / or TDOA measurement) of the reflection sensing signal 1240b. At least one processor (e.g., network device 1210a or 1220a) of the network device (e.g., network device 1210a or 1220a) may receive a reflection sensing signal 1240b. Fig. 20 The processor 2010) can then determine or calculate characteristics (e.g., position) of the RIS 1230 by using sensing measurements (e.g., Doppler measurements, RTT measurements, TOA measurements, and / or TDOA measurements) from the received reflected sensing signal 1240b.

[0201] Also during operation, a network device operating as a radar Tx (e.g., network device 1210b or 1220b) can send an RF sensing signal 1250a toward the RIS 1230. The RF sensing signal 1250a can be included in a communication signal and a sensing signal that are multiplexed together (e.g., via time division multiplexing and / or frequency division multiplexing) for joint communication and sensing purposes. The sensing signal 1250a can be reflected from the RIS 1230 to produce a reflected sensing signal (e.g., signal 1250b). Elements of the RIS 1230 (e.g., by using a back reflection coefficient) can cause the reflected sensing signal (e.g., signal 1250b) to be radiated in a direction back toward the network device (e.g., network device 1210b or 1220b).

[0202] A network device (e.g., network device 1210b or 1220b) operating as a radar Rx may receive a reflection sensing signal 1250b. After the network device (e.g., network device 1210b or 1220b) receives the reflection sensing signal 1250b, the network device (e.g., network device 1210b or 1220b) may obtain a measurement (e.g., Doppler measurement, RTT measurement, TOA measurement, and / or TDOA measurement) of the reflection sensing signal 1250b. At least one processor (e.g., Fig. 20 The processor 2010) can then determine or calculate characteristics (e.g., position) of the RIS 1230 by using sensing measurements (e.g., Doppler measurements, RTT measurements, TOA measurements, and / or TDOA measurements) from the received reflected sensing signal 1250b.

[0203] In order for the network devices (e.g., network devices 1210a, 1210b, 1220a, 1220b) to receive the reflected sensing signals (e.g., signals 1240b, 1250b), RIS 1230 should make the reflected signal direction the same as the incident signal direction. RIS 1230 can do this by providing RIS elements (e.g., Fig.11A A back reflection coefficient is applied at a RIS element 1110 of the RIS 1230 to make the reflected signal direction the same as the incident signal direction. Multiple values ​​of the back reflection coefficient associated with different incident directions can be applied at multiple resource units (e.g., sensing signal resources). After receiving the signal reflected from the RIS 1230 (e.g., signals 1240b, 1250b), the network device (e.g., network devices 1210a, 1210b, 1220a, 1220b) can determine the location of the RIS 1230 based on measurements (e.g., distance and angle of arrival) from the reflected signal (e.g., signals 1240b, 1250b).

[0204] In one or more aspects, if multiple network devices (e.g., network devices 1210a and 1210b) exist within system 1200, the network devices (e.g., network devices 1210a and 1210b) can each measure the distance to RIS 1230. Then, the position of RIS 1230 can be estimated to be located at the intersection of multiple circles formed with the measured distance as the radius. In some aspects, if a single network device (e.g., network device 1210a or network device 1210b) is equipped with multiple antennas (e.g., multiple Tx and Rx antennas), the network device can measure the angle of arrival (AoA) of RIS 1230 (e.g., based on beamforming or MIMO radar). Then, the position of RIS 1230 can be obtained by the network device (e.g., network device 1210a or network device 1210b) by using the measured AoA.

[0205] Compared to bistatic sensing in which the RIS applies the back reflection coefficient, single-station sensing in which the RIS applies the back reflection coefficient can greatly reduce the duration and complexity of the sensing process. For single-station sensing using the back reflection coefficient (e.g., when the network device and the RIS do not know each other's location), the RIS (e.g., Fig.13A RIS1330) can scan the common incident reflection direction in only one loop. In contrast, for bistatic sensing using back-reflection coefficients (e.g., when the network device and the RIS do not know each other's locations), the RIS (e.g., Fig. 13B The RIS1335) can scan the incident or reflected direction in two loops corresponding to the sending direction and the receiving direction respectively.

[0206] Fig.13Ais a diagram illustrating an example of a system 1300 for single-station sensing of a RIS 1330 by retro-reflection coefficient scanning. Fig.13A , system 1300 is shown to include a network device 1310 in the form of a base station (e.g., a gNB or a portion of a gNB, such as a CU, DU, RU, near-RT RIC, non-RT RIC, etc.). The network device 1310 (e.g., a gNB) can operate as a radar Tx and a radar receiver Rx for sensing purposes (e.g., for single-station sensing). The system 1300 also includes a network device 1320 in the form of a UE (e.g., a mobile phone (e.g., a smart phone). The network device 1320 (e.g., a UE) can operate as a radar Tx and a radar Rx for sensing purposes (e.g., for single-station sensing). The system 1300 additionally includes a RIS 1330.

[0207] During operation of the system 1300 for single-station sensing of the RIS 1330, a network device (e.g., network device 1310 or network device 1320) may transmit a sensing signal (e.g., signal 1350a) at an incident angle toward the RIS 1330. The RIS 1330 may scan the beam 1340 (e.g., loop beam scanning) to receive the transmitted sensing signal (e.g., 1350a). Once the RIS 1330 receives the transmitted sensing signal (e.g., 1350a), the RIS 1330 may reflect the transmitted sensing signal (e.g., 1350a) to produce a reflected sensing signal (e.g., signal 1350b) radiated at the incident angle (e.g., by applying a retro-reflection coefficient), such that the reflection angle of the reflected sensing signal (e.g., signal 1350b) is equal to the incident angle of the sensing signal (e.g., signal 1350a).

[0208] Fig. 13B is a diagram illustrating an example of a system 1305 for bistatic sensing of a RIS 1335 by retrospective reflection coefficient scanning. Fig.13A , system 1305 is shown to include network devices 1315a, 1315b in the form of a base station (e.g., a gNB or a portion of a gNB, such as a CU, DU, RU, near-RT RIC, non-RT RIC, etc.). Network devices 1315a, 1315b (e.g., gNB) can each operate as a radar Tx or a radar receiver Rx for sensing purposes (e.g., for dual-station sensing). System 1305 also includes network devices 1325a, 1325b in the form of a UE (e.g., a mobile phone (e.g., a smart phone)). Network devices 1325a, 1325b (e.g., UE) can each operate as a radar Tx or a radar Rx for sensing purposes (e.g., for dual-station sensing). System 1305 additionally includes RIS 1335.

[0209] During operation of the system 1305 for bistatic sensing of the RIS 1335, a network device (e.g., network device 1315a or network device 1325a) may transmit a sensing signal (e.g., signal 1365a) at an angle of incidence toward the RIS 1335. The RIS 1335 may scan the beam 1345 (e.g., first loop beam scan) to receive the transmitted sensing signal (e.g., 1365a). Once the RIS 1335 receives the transmitted sensing signal (e.g., 1365a), the RIS 1335 may reflect the transmitted sensing signal (e.g., 1365a) to produce a reflected sensing signal (e.g., signal 1350b). The RIS 1335 may then scan the beam 1355 (e.g., second loop beam scan) containing the reflected sensing signal (e.g., signal 1365b) so that another network device (e.g., network device 1315b or network device 1325b) may receive the reflected sensing signal (e.g., signal 1350b).

[0210] Fig.14 is a diagram illustrating example signaling 1440 that may be employed by the disclosed systems and techniques for sensing RIS 1410 by retro-reflection coefficient scanning. Fig.14 In the signaling 1400, the network device 1405 (e.g., gNB or UE) and the RIS 1410 are performing sensing and communicating with each other. For signaling 1400, the network device 1405 (e.g., gNB or UE) can send a message 1415 to the RIS 1410 to start the traceback mode.

[0211] In order to allow the network device 1405 (e.g., gNB or UE) to identify the signal reflected by the RIS 1410, the network device 1405 (e.g., gNB or UE) may configure a specific on / off mode to the RIS 1405. If there are multiple RISs in the system, the on / off modes of the RISs should be distinguishable from each other. The network device 1405 (e.g., gNB or UE) may send a message 1420 to the RIS 1410 to configure the specific on / off mode.

[0212] After RIS1410 receives messages 1415, 1420, RIS1410 can operate in retrospective mode (e.g., apply retroreflection coefficients) and can perform on / off switching according to the configured on / off mode for each retroreflection coefficient (e.g., apply the specific on / off mode requested) 1430.

[0213] In the backtracking mode, the RIS 1410 may sequentially apply a set of backtracking reflection coefficients {c k}、 k=1,…,K, where c k,iis the reflection coefficient at the i-th RIS element.

[0214] c k The value of can be previously calculated by RIS1410 based on the RIS component layout and carrier frequency. To ensure the back reflection,

[0215]

[0216] in And d i Equal to the distance between two RIS elements of RIS 1410.

[0217] Retroreflection coefficient c k Each retroreflection coefficient in can be related to the incident angle θ k is related and can be used at an incident angle of θ k When the reflection direction is the same as the incident direction, k Can be related to the angle of incidence is associated, so {c k} can be uniformly associated with the incident beam over the entire range of reflection angles.

[0218] After the network device 1405 (e.g., a gNB or a UE) sends messages 1415, 1420 to the RIS 1410, if the network device 1405 (e.g., a gNB or a UE) is equipped with multiple antennas, then for single-station sensing of the RIS 1410, the network device 1405 (e.g., a gNB or a UE) may simultaneously send a sensing reference signal beam 1425 to the RIS 1410 in different directions and receive a reflected sensing reference signal beam 1435 from the RIS 1410, while the RIS 1410 sequentially applies the traceback coefficients associated with the different directions.

[0219] In one or more aspects, the network device 1405 (e.g., a gNB or UE) may indicate a particular beam scanning pattern to the RIS 1410 such that the RIS 1410 may apply different back-reflection coefficients for each beam in turn. When the network device 1405 (e.g., a gNB or UE) transmits a sensing reference signal beam toward the RIS 1410, the RIS 1410 may use the back-reflection coefficient associated with the direction toward the network device 1405 (e.g., a gNB or UE) such that the signal received at the network device 1405 (e.g., a gNB or UE) may be the strongest signal strength.

[0220] The network device 1405 (e.g., a gNB or UE) may determine the beam 1440 (and the corresponding back-reflection coefficient) from the RIS 1410 using the strongest received signal strength. The network device 1405 (e.g., a gNB or UE) may then use the beam to determine (estimate) 1445 the distance and / or AoA to the RIS 1410. Based on the determined distance and / or AoA, the network device 1405 (e.g., a gNB or UE) may determine the location of the RIS 1410. The network device 1405 (e.g., a gNB or UE) may then send a message 1450 to the RIS 1410 to indicate the index of the selected back-reflection coefficient.

[0221] In one or more aspects, each retroreflection coefficient can be associated with a corresponding angle of incidence. Fig.15A , Fig. 15B and Fig. 15C Examples of reflected signals 1540a, 1540b, 1540c corresponding to the traceback coefficients associated with different incident angles are shown. Specifically, Fig.15A , 15B 15C are diagrams illustrating generation of reflection signals (e.g., of reflection signals 1540a, 1540b, 1504c) using retroreflection coefficients (e.g., c1, c2, and c3) associated with different incident angles associated with incident signals 1530a, 1530b, 1530c. Fig.15A , Fig. 15B and Fig. 15C RIS1520 can generate retroreflection coefficients (e.g., c1, c2, and c3) for incident angles of -30 degrees, 0 degrees, and 30 degrees, respectively. Fig.15A RIS 1520 may apply a retroreflection coefficient c1 that may generate a reflected signal 1540a at a -30 degree reflection angle, which is equal to the -30 degree incident angle of the incident signal 1530a. Fig. 15B RIS 1520 may apply a retroreflection coefficient c2 that may generate a reflected signal 1540b at a 0 degree reflection angle, which is equal to the 0 degree incident angle of the incident signal 1530b. Fig. 15C RIS1520 can apply a retroreflection coefficient c3, which can generate a reflected signal 1540c at a 30 degree reflection angle, which is equal to the 30 degree incident angle of the incident signal 1530c.

[0222] Fig.16 is a diagram 1600 illustrating an example of retro-reflection coefficient beam scanning. Fig.16In the embodiment of the present invention, a network device (e.g., a gNB or a UE) includes transmitters / receivers 1620a, 1620b, 1620c, and 1620d. The transmitters / receivers 1620a, 1620b, 1620c, and 1620d transmit and receive beams 1630a (e.g., beam 1), 1630b (e.g., beam 2), 1630c (e.g., beam 3), and 1630d (e.g., beam 4), which are scanned to different beam positions for each of the retro-reflection coefficients 1610 (e.g., c1, c2, c3, and c4). The transmitters / receivers 1620a, 1620b, 1620c, and 1620d may be a single transmitter / receiver device.

[0223] In one or more aspects, after completing the beam scanning pattern for each of the retroreflection coefficients 1610, the signal received at the network device (e.g., gNB or UE) has the strongest signal strength at a specific reference signal source (e.g., sensing signal source) having a specific beam (e.g., beam 3) and a specific coefficient (e.g., c4), and then the network device (e.g., gNB or UE) can communicate and / or sense the RIS using the specific beam (e.g., beam 3). In some aspects, the network device (e.g., gNB or UE) can indicate the index of the specific selected coefficient (e.g., c4) to the RIS.

[0224] For example, during operation, the RIS may apply a back-reflection coefficient c1. A transmitter / receiver 1620a of a network device (e.g., a gNB or UE) may transmit a beam 1630a (e.g., beam 1) to the RIS at a first beam scanning position. Using the back-reflection coefficient c1, the RIS will generate a reflected beam 1630a. A transmitter / receiver 1620b of a network device (e.g., a gNB or UE) may then transmit a beam 1630b (e.g., beam 2) to the RIS at a second beam scanning position. Using the back-reflection coefficient c1, the RIS will generate a reflected beam 1630b. A transmitter / receiver 1620c of a network device (e.g., a gNB or UE) may then transmit a beam 1630c (e.g., beam 3) to the RIS at a third beam scanning position. Using the back-reflection coefficient c1, the RIS will generate a reflected beam 1630c. The transmitter / receiver 1620d of the network device (e.g., gNB or UE) can then send a beam 1630d (e.g., beam 4) to the RIS at the fourth beam scanning position. Using the back-reflection coefficient c1, the RIS will generate a reflected beam 1630d.

[0225] The RIS may then apply the back-reflection coefficient c2. The transmitter / receiver 1620a of the network device (e.g., gNB or UE) may transmit a beam 1630a (e.g., beam 1) to the RIS at a first beam scanning position. Using the back-reflection coefficient c2, the RIS will generate a reflected beam 1630a. The transmitter / receiver 1620b of the network device (e.g., gNB or UE) may then transmit a beam 1630b (e.g., beam 2) to the RIS at a second beam scanning position. Using the back-reflection coefficient c2, the RIS will generate a reflected beam 1630b. The transmitter / receiver 1620c of the network device (e.g., gNB or UE) may then transmit a beam 1630c (e.g., beam 3) to the RIS at a third beam scanning position. Using the back-reflection coefficient c2, the RIS will generate a reflected beam 1630c. The transmitter / receiver 1620d of the network device (e.g., gNB or UE) can then send a beam 1630d (e.g., beam 4) to the RIS at the fourth beam scanning position. Using the back-reflection coefficient c2, the RIS will generate a reflected beam 1630d.

[0226] The RIS may then apply the back-reflection coefficient c3. The transmitter / receiver 1620a of the network device (e.g., gNB or UE) may transmit a beam 1630a (e.g., beam 1) to the RIS at a first beam scanning position. Using the back-reflection coefficient c3, the RIS will generate a reflected beam 1630a. The transmitter / receiver 1620b of the network device (e.g., gNB or UE) may then transmit a beam 1630b (e.g., beam 2) to the RIS at a second beam scanning position. Using the back-reflection coefficient c3, the RIS will generate a reflected beam 1630b. The transmitter / receiver 1620c of the network device (e.g., gNB or UE) may then transmit a beam 1630c (e.g., beam 3) to the RIS at a third beam scanning position. Using the back-reflection coefficient c3, the RIS will generate a reflected beam 1630c. The transmitter / receiver 1620d of the network device (e.g., gNB or UE) can then send a beam 1630d (e.g., beam 4) to the RIS at the fourth beam scanning position. Using the back-reflection coefficient c3, the RIS will generate a reflected beam 1630d.

[0227] The RIS may then apply the back-reflection coefficient c4. The transmitter / receiver 1620a of the network device (e.g., gNB or UE) may transmit a beam 1630a (e.g., beam 1) to the RIS at a first beam scanning position. Using the back-reflection coefficient c4, the RIS will generate a reflected beam 1630a. The transmitter / receiver 1620b of the network device (e.g., gNB or UE) may then transmit a beam 1630b (e.g., beam 2) to the RIS at a second beam scanning position. Using the back-reflection coefficient c4, the RIS will generate a reflected beam 1630b. The transmitter / receiver 1620c of the network device (e.g., gNB or UE) may then transmit a beam 1630c (e.g., beam 3) to the RIS at a third beam scanning position. Using the back-reflection coefficient c4, the RIS will generate a reflected beam 1630c. The transmitter / receiver 1620d of the network device (e.g., gNB or UE) can then send a beam 1630d (e.g., beam 4) to the RIS at a fourth beam scanning position. Using the back-reflection coefficient c4, the RIS will generate a reflected beam 1630d.

[0228] Then, after the network device (e.g., gNB or UE) has completed the beam scanning pattern for each of the back-reflection coefficients 1610 (e.g., c1, c2, c3, and c4), the network device (e.g., gNB or UE) can determine which beam it received from the RIS has the strongest signal strength. For example, the network device (e.g., gNB or UE) can determine that beam 3 (e.g., at the third beam scanning position) with back-reflection coefficient c4 has the strongest signal strength of all received beams. The network device (e.g., gNB or UE) can then use beam 3 to communicate and / or sense the RIS. The network device (e.g., gNB or UE) can also indicate the index of coefficient c4 to the RIS.

[0229] In one or more aspects, when the RIS applies a specific back reflection coefficient (e.g., c1 or c2), in order to allow a network device (e.g., a gNB or UE) to identify a signal (or propagation path) of the RIS or to allow a network device (e.g., a gNB or UE) to distinguish the RIS from other coexisting RISs, the RIS may adopt a method to be used at multiple occasions (e.g., Fig.17 The RIS backtracks to the specific open / close mode used at (e.g.,

[1010] ). Fig.17 is a diagram 1700 illustrating an example RIS on / off pattern (eg,

[1010] ). Fig.17, two RIS backtracking durations 1710, 1720 are shown. Each RIS backtracking duration 1710, 1720 is shown as including four time blocks. Specifically, RIS backtracking duration 1710 includes time blocks 1715a, 1715b, 1715c, 1715d. RIS backtracking duration 1720 includes time blocks 1725a, 1725b, 1725c, 1725d.

[0230] For each of the RIS backtracking durations 1710, 1720, the RIS may apply a specific backtracking reflection coefficient. For example, for the RIS backtracking duration 1710, the RIS may apply the backtracking reflection coefficient c1. For the RIS backtracking duration 1720, the RIS may apply the backtracking reflection coefficient c2.

[0231] For each of the RIS backtracking durations 1710, 1720, the RIS may follow a specific on / off pattern (e.g.,

[1010] ). For example, for the RIS backtracking duration 1710, for time blocks 1715a and 1715c, the RIS may be on for reflection; and for time blocks 1715b and 1715d, the RIS may be off and not reflective. For the RIS backtracking duration 1720, for time blocks 1725a and 1725c, the RIS may be on for reflection; and for time blocks 1725b and 1725d, the RIS may be off and not reflective.

[0232] In one or more aspects, in each RIS traceback duration 1710, 1720, the RIS may use the same traceback reflection coefficient and may follow a configured on / off pattern (e.g.,

[1010] ). In some aspects, a network device (e.g., a gNB or UE) should use the same beam within one RIS traceback duration 1710, 1720.

[0233] Fig.17 Also included are measured power delay profiles 1750, 1760 corresponding to each of the RIS backtracking durations 1710, 1720. Each measured power delay profile 1750, 1760 includes a plurality of reflection paths. For example, the measured power delay profile 1750 includes a reflection path 1730 from an object other than the RIS. The measured power delay profile 1760 includes the same reflection path 1730 from an object other than the RIS, and additionally includes a RIS reflection path 1740 (e.g., a reflection path from the RIS).

[0234] In one or more aspects, if the time domain positions of all measured power delay profiles (e.g., power delay profile result 2 1760) having a reflection path that is not present in other measured power delay profiles (e.g., power delay profile result 1 1750) in the RIS backtracking duration (e.g., RIS backtracking duration 1720) correspond to the configured on / off mode, then the backtracking reflection coefficient (e.g., c2) for the RIS backtracking duration (e.g., RIS backtracking duration 1720) can be selected for use. In some aspects, a reflection path (e.g., RIS reflection path 1740) that is not present in other measured power delay profiles (e.g., power delay profile result 1 1750) corresponds to a RIS reflection.

[0235] Fig.18 is a flow chart illustrating an example of a process 1800 for wireless communication utilizing a method for sensing RIS by back-tracing reflection coefficient scanning. The process 1800 may be performed by a network device such as a UE, a base station (e.g., a gNB), a portion of a base station (e.g., one or more of a CU, DU, RU, and / or other portions of a base station having a disaggregated architecture), or a component or system (e.g., a chipset) of a UE or a base station. The UE may be a mobile device (e.g., a mobile phone), a vehicle, a wearable device (e.g., a network-connected watch or other wearable device), an extended reality (XR) device (e.g., a virtual reality (VR) or augmented reality (AR) headset or glasses), or other type of UE. The operations of the process 1800 may be implemented as a processor on one or more processors (e.g., Fig. 20 The software components executed and run on the processor 2010 or other processors of the wireless communication device. In addition, the wireless communication device can be enabled to send and receive signals in the process 1800, for example, through one or more antennas and / or one or more transceivers (e.g., wireless transceivers).

[0236] At block 1810, a network device (or a component thereof) may transmit a plurality of reference signal beams in a plurality of directions to a reconfigurable smart surface (RIS).

[0237] At box 1820, the network device (or its components) may receive multiple reflected reference signal beams in multiple directions from the RIS based on multiple back-reflection coefficients. In some cases, the multiple reflected reference signal beams include sensing reference signal beams and / or communication reference signal beams. In some aspects, the network device (or its components) may receive a beam scanning message from the network device, the beam scanning message including an indication for applying a beam scanning mode using the multiple back-reflection coefficients. In some cases, the network device (or its components) may send a switching mode message to the RIS, the switching mode message including an indication of an on-off mode for each back-reflection coefficient in the multiple back-reflection coefficients. In some examples, the network device (or its components) may determine a power delay profile for each back-reflection coefficient in the multiple back-reflection coefficients.

[0238] At block 1830, the network device (or a component thereof) may measure a signal strength of each reflected reference signal beam in each of a plurality of directions for each of a plurality of back reflection coefficients.

[0239] At block 1840, the network device (or its components) may determine a selected beam direction in a plurality of directions and a selected back-reflection coefficient in a plurality of back-reflection coefficients based on the measured signal strength. In some aspects, the network device (or its components) may determine a selected power delay profile based on the path of a reflected reference signal beam in a plurality of reflected reference signal beams (e.g., from a power delay profile determined for a plurality of back-reflection coefficients). In such aspects, the network device (or its components) may determine a selected back-reflection coefficient based on the selected power delay profile for the RIS. In some cases, the network device (or its components) may send a back-reflection coefficient message including an indication of the selected back-reflection coefficient to the RIS.

[0240] In some aspects, the network devices (or their components) may determine the location of the RIS using a reflected reference signal beam associated with a selected beam direction and a selected back-reflection coefficient. In some cases, to determine the location of the RIS, the network devices (or their components) may determine a distance from the network device to the RIS and / or an angle of arrival (AoA) of a reflected reference signal beam from the RIS. In some examples, the network devices (or their components) may use the location of the RIS as a reference point for sensing one or more locations of one or more objects.

[0241] Fig.191 is a flow chart illustrating an example of a process 1900 for wireless communication utilizing a method for sensing RIS by back-reflection coefficient scanning. The process 1900 may be performed by a RIS or by a component or system (e.g., a chipset) of a RIS. The operations of the process 1900 may be implemented as a processor (e.g., a processor) on one or more processors (e.g., Fig. 20 The software components executed and run on the processor 2010 or other processors of the wireless communication device. In addition, the wireless communication device can be enabled to send and receive signals in the process 1900, for example, through one or more antennas and / or one or more transceivers (e.g., wireless transceivers).

[0242] At block 1910, the RIS (or components thereof) may receive a plurality of reference signal beams in a plurality of directions from a network device.

[0243] At block 1920, the RIS (or its components) may send multiple reflected reference signal beams in multiple directions to the network device based on multiple back-reflection coefficients. In some cases, the multiple reflected reference signal beams include sensing reference signal beams and / or communication reference signal beams. In some aspects, the RIS (or its components) may receive a beam scanning message from the network device, the beam scanning message including an indication for applying a beam scanning mode using the multiple back-reflection coefficients. In some cases, the RIS (or its components) may receive a switching mode message from the network device, the switching mode message including an indication of an on-off mode for each back-reflection coefficient in the multiple back-reflection coefficients.

[0244] At block 1930, the RIS (or a component thereof) may receive a back-reflection coefficient message from a network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient from a plurality of back-reflection coefficients.

[0245] Fig. 20 is a block diagram illustrating an example of a computing system 2000 that may be employed by the disclosed systems and techniques for sensing RIS by retroreflection coefficient scanning. Specifically, Fig. 20 An example of a computing system 2000 is illustrated, which may be any computing device, for example, constituting an internal computing system, a remote computing system, a camera, or any components thereof, wherein the components of the system communicate with each other using connection 2005. Connection 2005 may be a physical connection using a bus, or a direct connection into processor 2010, such as in a chipset architecture. Connection 2005 may also be a virtual connection, a networked connection, or a logical connection.

[0246] In some aspects, computing system 2000 is a distributed system, where the functionality described in the present disclosure may be distributed within a data center, multiple data centers, a peer-to-peer network, etc. In some aspects, one or more of the described system components represent a number of such components that each perform a portion or all of the functionality for which the component is described. In some aspects, each component may be a physical or virtual device.

[0247] The example system 2000 includes at least one processing unit (CPU or processor) 2010 and connections 2005 that communicatively couple various system components including system memory 2015, such as read-only memory (ROM) 2020 and random access memory (RAM) 2025, to the processor 2010. The computing system 2000 may include a cache 2012 of high-speed memory directly connected to the processor 2010, in close proximity to the processor, or integrated as part of the processor.

[0248] Processor 2010 may include any general purpose processor and hardware or software services, such as services 2032, 2034, and 2036 stored in storage device 2030, that are configured to control processor 2010 as well as a dedicated processor where software instructions are incorporated into the actual processor design. Processor 2010 may essentially be a completely independent computing system containing multiple cores or processors, buses, memory controllers, caches, etc. Multi-core processors may be symmetric or asymmetric.

[0249] To enable user interaction, the computing system 2000 includes an input device 2045 that can represent any number of input mechanisms, such as a microphone for voice, a touch-sensitive screen for gesture or graphical input, a keyboard, a mouse, motion input, voice, etc. The computing system 2000 may also include an output device 2035 that can be one or more of a plurality of output mechanisms. In some cases, a multimodal system may enable a user to provide multiple types of input / output to communicate with the computing system 2000.

[0250] The computing system 2000 may include a communication interface 2040, which may generally govern and manage user input and system output. The communication interface may perform or facilitate receiving and / or sending wired or wireless communications using wired and / or wireless transceivers, including using an audio jack / plug, a microphone jack / plug, a Universal Serial Bus (USB) port / plug, an Apple TM Lightning TM Ports / plugs, Ethernet ports / plugs, Fiber optic ports / plugs, Dedicated wired ports / plugs, 3G, 4G, 5G and / or other cellular data network wireless signal delivery, Bluetooth TMWireless signal transmission, Bluetooth TM Low Energy (BLE) wireless signal transmission, IBEACON TM Wireless signal transmission, radio frequency identification (RFID) wireless signal transmission, near field communication (NFC) wireless signal transmission, dedicated short range communication (DSRC) wireless signal transmission, 802.11 Wi-Fi wireless signal transmission, wireless local area network (WLAN) signal transmission, visible light communication (VLC), World Interoperability for Microwave Access (WiMAX), infrared (IR) communication wireless signal transmission, public switched telephone network (PSTN) signal transmission, integrated services digital network (ISDN) signal transmission, ad hoc network signal transmission, radio wave signal transmission, microwave signal transmission, infrared signal transmission, visible light signal transmission, ultraviolet light signal transmission, wireless signal transmission along the electromagnetic spectrum, or some combination thereof.

[0251] The communication interface 2040 may also include one or more range finding sensors (e.g., LIDAR sensors, laser range finders, RF radars, ultrasonic sensors, and infrared (IR) sensors) configured to collect data and provide measurements to the processor 2010, whereby the processor 2010 may be configured to perform determinations and calculations required to obtain various measurements of the one or more range finding sensors. In some examples, the measurements may include flight time, wavelength, azimuth, elevation, distance, linear velocity, and / or angular velocity, or any combination thereof. The communication interface 2040 may also include one or more global navigation satellite system (GNSS) receivers or transceivers for determining the location of the computing system 2000 based on receiving one or more signals from one or more satellites associated with one or more GNSS systems. GNSS systems include, but are not limited to, the United States' GPS, Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System (BDS), and Europe's Galileo GNSS. There is no restriction to operating on any particular hardware arrangement, and thus the underlying features herein may be easily substituted for improved hardware or firmware arrangements as they are developed.

[0252] The storage device 2030 may be a non-volatile and / or non-transitory and / or computer-readable memory device, and may be a hard disk or other type of computer-readable medium that can store data accessible by a computer, such as a magnetic cassette, a flash memory card, a solid-state memory device, a digital versatile disk, a cassette, a floppy disk, a floppy disk, a hard disk, a magnetic tape, a magnetic stripe / magnetic stripe, any other magnetic storage medium, flash memory, a memristor memory, any other solid-state memory, a compact disk-read only memory (CD-ROM) optical disk, a rewritable compact disk (CD) optical disk, a digital video disk (DVD) optical disk, a Blu-ray disc (BDD) optical disk, a holographic optical disk, another optical medium, a secure digital (SD) card, a micro secure digital (microSD) card, card, a smart card chip, an EMV chip, a subscriber identity module (SIM) card, a mini / micro / nano / pico SIM card, another integrated circuit (IC) chip / card, a random access memory (RAM), a static RAM (SRAM), a dynamic RAM (DRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash EPROM (FLASH EPROM), a cache memory (e.g., a layer 1 (L1) cache, a layer 2 (L2) cache, a layer 3 (L3) cache, a layer 4 (L4) cache, a layer 5 (L5) cache, other (L#) cache), a resistive random access memory (RRAM / ReRAM), a phase change memory (PCM), a spin transfer torque RAM (STT-RAM), another memory chip or box, and / or a combination thereof.

[0253] Storage device 2030 may include software services, servers, services, etc., which, when the code defining such software is executed by processor 2010, causes the system to perform functions. In some aspects, hardware services that perform specific functions may include software components for performing functions stored in a computer-readable medium connected to necessary hardware components (such as processor 2010, connection 2005, output device 2035, etc.). The term "computer-readable medium" includes, but is not limited to, portable or non-portable storage devices, optical storage devices, and various other media capable of storing, containing or carrying instructions and / or data. Computer-readable media may include non-transient media in which data may be stored and does not include carrier waves and / or transient electronic signals propagated wirelessly or on a wired connection. Examples of non-transient media may include, but are not limited to, disks or tapes, optical storage media (such as compact discs (CDs) or digital versatile discs (DVDs)), flash memory, memory, or memory devices. Computer readable media may store thereon code and / or machine executable instructions, which may represent a procedure, function, subprogram, program, routine, subroutine, module, software package, category, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by transmitting and / or receiving information, data, independent variables, parameters, or memory contents. Information, independent variables, parameters, data, etc. may be transmitted, forwarded, or sent via any suitable means, including memory sharing, message passing, token passing, network sending, etc.

[0254] Specific details are provided in the above description to provide a thorough understanding of the various aspects and examples provided herein, but those skilled in the art will recognize that the application is not limited thereto. Therefore, although the exemplary aspects of the present application have been described in detail herein, it is to be understood that each inventive concept can be embodied and adopted in various other ways, and the appended claims are not intended to be interpreted as including these variations, unless limited by the prior art. The various features and aspects of the above-mentioned applications can be used individually or in combination. In addition, without departing from the broader scope of this specification, each aspect can be used in any number of environments and applications beyond the environment and application described herein. Therefore, the description and the accompanying drawings should be considered as illustrative rather than restrictive. For the purpose of illustration, each method is described in a specific order. It should be appreciated that, in alternative aspects, each method can be performed in an order different from the described order.

[0255] For clarity of explanation, in some instances, the present technology may be presented as including separate functional blocks, which include devices, device components, steps or routines in the method embodied in software or a combination of hardware and software. Additional components other than those components shown in the drawings and / or described herein may be used. For example, circuits, systems, networks, processes and other components may be shown as components in block diagram form to avoid confusing these aspects in unnecessary details. In other instances, known circuits, processes, algorithms, structures and techniques may be shown without unnecessary details to avoid confusing various aspects.

[0256] In addition, it will be appreciated by those skilled in the art that the various exemplary logic blocks, modules, circuits and algorithmic steps described in conjunction with the aspects disclosed herein can be implemented as electronic hardware, computer software or a combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various exemplary components, frames, modules, circuits and steps have been generally described in terms of their functionality. Whether such functions are implemented as hardware or software depends on specific applications and the design constraints proposed to the entire system. Those skilled in the art can implement the described functionality in different ways for each specific application, but such specific implementation decisions should not be interpreted as causing deviations from the scope of the present disclosure.

[0257] Various aspects may be described above as a process or method, which is depicted as a flow chart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flow chart may describe an operation as a sequential process, many operations in the operation may be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. The process is terminated when the operation of the process is completed, but the process may have additional steps not included in the accompanying drawings. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, the termination of the process may correspond to the function returning to the calling function or the main function.

[0258] The processes and methods according to the above examples can be implemented using stored computer executable instructions or otherwise obtained from computer readable media. Such instructions may include, for example, instructions and data that configure a general-purpose computer, a special-purpose computer, or a processing device to perform a certain function or function group. Parts of the computer resources used can be accessed through a network. Computer executable instructions can be, for example, binary, intermediate format instructions such as assembly language, firmware, source code. Examples of computer readable media that can be used to store instructions, information used, and / or information created during the method according to the described examples include disks or optical disks, flash memories, USB devices with non-volatile memory, networked storage devices, etc.

[0259] In some embodiments, computer-readable storage devices, media, and memories may include wired or wireless signals containing bit streams, etc. However, when referred to, non-transitory computer-readable storage media explicitly excludes media such as power consumption, carrier signals, electromagnetic waves, and signals themselves.

[0260] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof in some cases, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0261] The various illustrative logic blocks, modules, and circuits described in conjunction with the various aspects disclosed herein may be implemented or executed using hardware, software, firmware, middleware, microcode, hardware description language, or any combination thereof, and may be implemented in any of a variety of form factors. When implemented in software, firmware, middleware, or microcode, program code or code segments (e.g., computer program products) for performing necessary tasks may be stored in a computer-readable or machine-readable medium. The processor may perform the necessary tasks. Examples of various form factors include: laptops, smart phones, mobile phones, tablet devices, or other small form factor personal computers, personal digital assistants, rack-mounted devices, stand-alone devices, etc. The functionality described herein may also be embodied in peripheral devices or add-in cards. By way of additional examples, such functionality may also be implemented on circuit boards in different chips or different processes executed on a single device.

[0262] Instructions, media for conveying such instructions, computing resources for executing them, and other structures for supporting such computing resources are example means for providing the functionality described in this disclosure.

[0263] The technology described herein may also be implemented in electronic hardware, computer software, firmware, or any combination thereof. Such technology may be implemented in any of a variety of devices, such as general-purpose computers, wireless communication device mobile phones, or integrated circuit devices with multiple uses, including applications in wireless communication device mobile phones and other devices. Any features described as modules or components may be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. If implemented in software, the technology may be implemented at least in part by a computer-readable data storage medium including a program code, which includes instructions for executing one or more of the above-mentioned methods, algorithms, and / or operations when executed. The computer-readable data storage medium may form a part of a computer program product, which may include packaging materials. The computer-readable medium may include a memory or data storage medium, such as a random access memory (RAM) (such as a synchronous dynamic random access memory (SDRAM)), a read-only memory (ROM), a non-volatile random access memory (NVRAM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic or optical data storage medium, etc. Additionally or alternatively, the technology may be implemented at least in part by a computer-readable communication medium that carries or communicates program code in the form of instructions or data structures and that can be accessed, read, and / or executed by a computer, such as a propagated signal or wave.

[0264] The program code may be executed by a processor, which may include one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Such a processor may be configured to perform any of the techniques described in the present disclosure. A general-purpose processor may be a microprocessor; however, in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. Therefore, the term "processor" as used herein may refer to any of the foregoing structures, any combination of the foregoing structures, or any other structure or device suitable for implementing the techniques described herein.

[0265] It should be understood by those of ordinary skill in the art that the less than ("<") and greater than (">") symbols or terms used herein may be replaced by less than or equal to ("≤") and greater than or equal to ("≥") symbols, respectively, without departing from the scope of the present specification.

[0266] Where a component is described as being “configured to” perform certain operations, such configuration may be achieved, for example, by designing electronic circuits or other hardware to perform the operations, by programming programmable electronic circuits (e.g., a microprocessor or other suitable electronic circuits) to perform the operations, or any combination thereof.

[0267] The phrases “coupled to” or “communicatively coupled to” refer to any component being physically connected directly or indirectly to another component, and / or any component being in communication with another component directly or indirectly (e.g., connected to the other component via a wired or wireless connection and / or other suitable communication interface).

[0268] Claim language or other language reciting "at least one of" a set and / or "one or more of" a set indicates that one member of the set or multiple members of the set (in any combination) satisfies the claim. For example, claim language reciting "at least one of A and B" or "at least one of A or B" means A, B, or A and B. In another example, claim language reciting "at least one of A, B, and C" or "at least one of A, B, or C" means A, B, C, or A and B, or A and C, or B and C, or A and B and C. The language "at least one of" a set and / or "one or more of" a set does not limit the set to the items listed in the set. For example, claim language reciting "at least one of A and B" or "at least one of A or B" may mean A, B, or A and B, and may additionally include items not listed in the set of A and B.

[0269] Illustrative aspects of the present disclosure include:

[0270] Aspect 1. A method of wireless communication performed at a network device, the method comprising: sending multiple reference signal beams in multiple directions to a reconfigurable smart surface (RIS); receiving multiple reflected reference signal beams in the multiple directions from the RIS based on multiple back-reflection coefficients; measuring the signal strength of each reflected reference signal beam in each of the multiple directions for each of the multiple back-reflection coefficients; and determining a selected beam direction among the multiple directions and a selected back-reflection coefficient among the multiple back-reflection coefficients based on measuring the signal strengths.

[0271] Aspect 2. The method according to aspect 1 further comprises: sending a beam scanning message to the RIS, the beam scanning message comprising an indication for applying a beam scanning mode using the plurality of retro-reflection coefficients.

[0272] Aspect 3. The method according to any one of aspects 1 to 2, further comprising: determining the position of the RIS using a reflected reference signal beam associated with the selected beam direction and the selected back-reflection coefficient.

[0273] Aspect 4. The method according to aspect 3, wherein determining the location of the RIS comprises determining at least one of a distance from the network device to the RIS or an angle of arrival (AoA) of the reflected reference signal beam from the RIS.

[0274] Aspect 5. The method according to any one of aspects 3 or 4, further comprising: using the position of the RIS as a reference point for sensing one or more positions of one or more objects.

[0275] Aspect 6. The method according to any one of aspects 1 to 5, further comprising: sending a switching mode message to the RIS, the switching mode message comprising an indication of an on-off mode for each of the plurality of retroreflection coefficients.

[0276] Aspect 7. The method according to any one of aspects 1 to 6, further comprising: determining a power delay profile for each of the plurality of retroreflection coefficients.

[0277] Aspect 8. According to the method described in any one of Aspects 1 to 7, the method further includes: determining a selected power delay distribution based on the path of a reflected reference signal beam among the multiple reflected reference signal beams; and determining the selected retrospective reflection coefficient for the RIS based on the selected power delay distribution.

[0278] Aspect 9. The method according to any one of aspects 1 to 8, the method further comprising: sending a retroreflection coefficient message including an indication of the selected retroreflection coefficient to the RIS.

[0279] Aspect 10. The method according to any one of aspects 1 to 9, wherein the network device is one of a user equipment (UE) or a base station.

[0280] Aspect 11. A method according to aspect 10, wherein the base station is a next generation Node B (gNB).

[0281] Aspect 12. The method according to any one of aspects 1 to 11, wherein the plurality of reflected reference signal beams include at least one of a sensing reference signal beam or a communication reference signal beam.

[0282] Aspect 13. A network device for wireless communication, the network device comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and configured to: output multiple reference signal beams in multiple directions for sending to a reconfigurable smart surface (RIS); receive multiple reflected reference signal beams in the multiple directions from the RIS based on multiple back-reflection coefficients; measure the signal strength of each reflected reference signal beam in each of the multiple directions for each of the multiple back-reflection coefficients; and determine a selected beam direction among the multiple directions and a selected back-reflection coefficient among the multiple back-reflection coefficients based on measuring the signal strength.

[0283] Aspect 14. The network device according to aspect 13, the beam scanning message includes an indication for applying a beam scanning mode using the plurality of retro-reflection coefficients.

[0284] Aspect 15. A network device according to any one of Aspects 13 to 14, wherein the at least one processor is configured to determine the position of the RIS using a reflected reference signal beam associated with the selected beam direction and the selected back-reflection coefficient.

[0285] Aspect 16. A network device according to Aspect 15, wherein in order to determine the location of the RIS, wherein the at least one processor is configured to determine at least one of a distance from the network device to the RIS or an angle of arrival (AoA) of the reflected reference signal beam from the RIS.

[0286] Aspect 17. A network device according to any one of Aspects 15 or 16, wherein the at least one processor is configured to use the position of the RIS as a reference point for sensing one or more positions of one or more objects.

[0287] Aspect 18. A network device according to any one of Aspects 13 to 17, wherein the at least one processor is configured to output a switching mode message for sending to the RIS, the switching mode message comprising an indication of an on-off mode for each of the plurality of back-reflection coefficients.

[0288] Aspect 19. The network device according to any one of aspects 13 to 18, wherein the at least one processor is configured to determine a power delay profile for each of the plurality of retro-reflection coefficients.

[0289] Aspect 20. A network device according to any one of Aspects 13 to 19, wherein the at least one processor is configured to: determine a selected power delay profile based on a path of a reflected reference signal beam among the multiple reflected reference signal beams; and determine the selected back-reflection coefficient for the RIS based on the selected power delay profile.

[0290] Aspect 21. A network device according to any one of aspects 13 to 20, wherein the at least one processor is configured to output a back-reflection coefficient message for sending to the RIS, the back-reflection coefficient message including an indication of the selected back-reflection coefficient.

[0291] Aspect 22. A network device according to any one of aspects 13 to 21, wherein the network device is one of a user equipment (UE) or a base station.

[0292] Aspect 23. A network device according to Aspect 22, wherein the base station is a next generation Node B (gNB).

[0293] Aspect 24. A network device according to any one of aspects 13 to 23, wherein the plurality of reflected reference signal beams include at least one of a sensing reference signal beam or a communication reference signal beam.

[0294] Aspect 25. A reconfigurable smart surface (RIS) for wireless communication, the reconfigurable smart surface (RIS) comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory and configured to: receive multiple reference signal beams in multiple directions from a network device; output multiple reflected reference signal beams in the multiple directions based on multiple back-reflection coefficients for sending to the network device; and receive a back-reflection coefficient message from the network device, the back-reflection coefficient message comprising an indication of a selected back-reflection coefficient from the multiple back-reflection coefficients.

[0295] Aspect 26. The RIS according to aspect 25, wherein the at least one processor is configured to receive a beam scanning message from the network device, the beam scanning message including an indication for applying a beam scanning mode using the plurality of retro-reflection coefficients.

[0296] Aspect 27. The RIS according to any one of Aspects 25 to 26, wherein the at least one processor is configured to receive a switching mode message from the network device, the switching mode message comprising an indication of an on-off mode for each of the plurality of back-reflection coefficients.

[0297] Aspect 28. The RIS according to any one of aspects 25 to 27, wherein the network device is one of a user equipment (UE) or a base station.

[0298] Aspect 29. A RIS according to any one of Aspects 25 to 28, wherein the base station is a next generation Node B (gNB).

[0299] Aspect 30. The RIS according to any one of aspects 25 to 29, wherein the plurality of reflected reference signal beams include at least one of a sensing reference signal beam or a communication reference signal beam.

[0300] Aspect 31. A method for wireless communication performed by a reconfigurable smart surface (RIS), the method comprising: receiving multiple reference signal beams in multiple directions from a network device at the RIS; sending multiple reflected reference signal beams in the multiple directions to the network device based on multiple back-reflection coefficients; and receiving a back-reflection coefficient message from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient from the multiple back-reflection coefficients.

[0301] Aspect 32. The method according to aspect 31, the method further comprising: receiving a beam scanning message from the network device, the beam scanning message comprising an indication for applying a beam scanning mode using the plurality of retro-reflection coefficients.

[0302] Aspect 33. The method according to any one of Aspects 31 to 32, further comprising: receiving a switching mode message from the network device, the switching mode message comprising an indication of an on-off mode for each of the multiple back-reflection coefficients.

[0303] Aspect 34. A method according to any one of aspects 31 to 33, wherein the network device is one of a user equipment (UE) or a base station.

[0304] Aspect 35. A method according to any one of Aspects 31 to 34, wherein the base station is a next generation Node B (gNB).

[0305] Aspect 36. A method according to any one of aspects 31 to 35, wherein the plurality of reflected reference signal beams include at least one of a sensing reference signal beam or a communication reference signal beam.

[0306] Aspect 37. A non-transitory computer-readable medium having instructions stored thereon, which, when executed by one or more processors, cause the one or more processors to perform the operations of any one of Aspects 1 to 12.

[0307] Aspect 38. An apparatus for wireless communication, the apparatus comprising: one or more components for performing the operations according to any one of aspects 1 to 12.

[0308] Aspect 39. A non-transitory computer-readable medium having instructions stored thereon, which, when executed by one or more processors, cause the one or more processors to perform operations according to any one of Aspects 31 to 36.

[0309] Aspect 40. An apparatus for wireless communication, the apparatus comprising: one or more components for performing the operations according to any one of aspects 31 to 36.

[0310] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be consistent with the full scope consistent with the language claims, where elements mentioned in the singular are not intended to mean "one and only one", unless specifically stated otherwise, but rather "one or more".

Claims

1. A method of wireless communication performed at a network device, the method comprising: sending a plurality of reference signal beams in a plurality of directions to a reconfigurable smart surface (RIS); receiving a plurality of reflected reference signal beams in the plurality of directions from the RIS based on a plurality of retro-reflection coefficients; measuring, for each of the plurality of retroreflection coefficients, a signal strength of each reflected reference signal beam in each of the plurality of directions; as well as A selected beam direction from among the plurality of directions and a selected back reflection coefficient from among the plurality of back reflection coefficients are determined based on measuring the signal strength.

2. The method according to claim 1, further comprising: A beam scanning message is sent to the RIS, the beam scanning message including an indication for applying a beam scanning mode using the plurality of retroreflection coefficients.

3. The method according to claim 1, further comprising: A position of the RIS is determined using a reflected reference signal beam associated with the selected beam direction and the selected back-reflection coefficient.

4. The method of claim 3, wherein determining the location of the RIS comprises determining at least one of a distance from the network device to the RIS or an angle of arrival (AoA) of the reflected reference signal beam from the RIS.

5. The method according to claim 3, further comprising: The position of the RIS is used as a reference point for sensing one or more positions of one or more objects.

6. The method according to claim 1, further comprising: A switch mode message is sent to the RIS, the switch mode message including an indication of an on-off mode for each of the plurality of retroreflection coefficients.

7. The method according to claim 1, further comprising: A power delay profile is determined for each of the plurality of retroreflection coefficients.

8. The method according to claim 1, further comprising: determining a selected power delay profile based on a path of a reflected reference signal beam among the plurality of reflected reference signal beams; as well as The selected retroreflection coefficient is determined for the RIS based on the selected power delay profile.

9. The method according to claim 1, further comprising: A retroreflection coefficient message including an indication of the selected retroreflection coefficient is sent to the RIS.

10. The method of claim 1, wherein the network device is one of a user equipment (UE) or a base station.

11. The method of claim 10, wherein the base station is a next generation Node B (gNB).

12. The method of claim 1, wherein the plurality of reflected reference signal beams comprises at least one of a sensing reference signal beam or a communication reference signal beam.

13. A network device for wireless communication, the network device comprising: at least one memory; and at least one processor coupled to at least one memory and configured to: Outputting a plurality of reference signal beams in a plurality of directions for sending to a reconfigurable smart surface (RIS); receiving a plurality of reflected reference signal beams in the plurality of directions from the RIS based on a plurality of retro-reflection coefficients; measuring, for each of the plurality of retroreflection coefficients, a signal strength of each reflected reference signal beam in each of the plurality of directions; as well as A selected beam direction from among the plurality of directions and a selected back reflection coefficient from among the plurality of back reflection coefficients are determined based on measuring the signal strength.

14. The network device of claim 13, wherein the at least one processor is configured to receive a beam scanning message from the network device, the beam scanning message comprising an indication for applying a beam scanning mode using the plurality of retro-reflection coefficients.

15. The network device of claim 13, wherein the at least one processor is configured to determine the location of the RIS using a reflected reference signal beam associated with the selected beam direction and the selected back-reflection coefficient.

16. The network device of claim 15, wherein to determine the location of the RIS, the at least one processor is configured to determine at least one of a distance from the network device to the RIS or an angle of arrival (AoA) of the reflected reference signal beam from the RIS.

17. The network device of claim 15, wherein the at least one processor is configured to use the location of the RIS as a reference point for sensing one or more locations of one or more objects.

18. The network device of claim 13, wherein the at least one processor is configured to output a switch mode message for sending to the RIS, the switch mode message comprising an indication of an on-off mode for each of the plurality of back-reflection coefficients.

19. The network device of claim 13, wherein the at least one processor is configured to determine a power delay profile for each of the plurality of retroreflection coefficients.

20. The network device of claim 13, wherein the at least one processor is configured to: determining a selected power delay profile based on a path of a reflected reference signal beam of the plurality of reflected reference signal beams; and The selected retroreflection coefficient is determined for the RIS based on the selected power delay profile.

21. The network device of claim 13, wherein the at least one processor is configured to output a back-reflection coefficient message for sending to the RIS, the back-reflection coefficient message including an indication of the selected back-reflection coefficient.

22. The network device of claim 13, wherein the network device is one of a user equipment (UE) or a base station.

23. The network device of claim 22, wherein the base station is a next generation Node B (gNB).

24. The network device of claim 13, wherein the plurality of reflected reference signal beams include at least one of sensing reference signal beams or communication reference signal beams.

25. A reconfigurable intelligent surface (RIS) for wireless communication, the reconfigurable intelligent surface (RIS) comprising: at least one memory; and at least one processor coupled to at least one memory and configured to: receiving a plurality of reference signal beams in a plurality of directions from a network device; Outputting a plurality of reflected reference signal beams in the plurality of directions based on a plurality of back-reflection coefficients for sending to the network device; as well as A back-reflection coefficient message is received from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient of the plurality of back-reflection coefficients.

26. The RIS of claim 25, wherein the at least one processor is configured to receive a beam scanning message from the network device, the beam scanning message including an indication to apply a beam scanning mode using the plurality of retro-reflection coefficients.

27. The RIS of claim 25, wherein the at least one processor is configured to receive a switch mode message from the network device, the switch mode message comprising an indication of an on-off mode for each of the plurality of back-reflection coefficients.

28. The RIS of claim 25, wherein the network device is one of a user equipment (UE) or a base station, and wherein the base station is a next generation Node B (gNB).

29. The RIS of claim 25, wherein the plurality of reflected reference signal beams include at least one of sensing reference signal beams or communication reference signal beams.

30. A method of wireless communication performed by a reconfigurable intelligent surface (RIS), the method comprising: receiving, at the RIS, a plurality of reference signal beams in a plurality of directions from a network device; Sending a plurality of reflected reference signal beams in the plurality of directions to the network device based on a plurality of back-reflection coefficients; as well as A back-reflection coefficient message is received from the network device, the back-reflection coefficient message including an indication of a selected back-reflection coefficient of the plurality of back-reflection coefficients.

Images