Backscatter-based localization

Abstract

This disclosure provides systems, methods, and devices for wireless communication supporting backscatter-based positioning. In a first aspect, a method of wireless communication includes transmitting a configuration signal indicating a tag address of a tag device and a modulation scheme for generating a backscatter signal (402). The method also includes transmitting a positioning reference signal (PRS) after transmitting the configuration signal (404). The method also includes receiving a backscatter signal (406) from the tag device based on the modulation scheme and the PRS. Other aspects and features are also claimed and described.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Patent Application No. 18 / 060,429, entitled "BACKSCATTER - BASED POSITIONING", filed on November 30, 2022, which is hereby incorporated by reference in its entirety. Technical Field

[0003] Aspects of the present disclosure generally relate to wireless communication systems, and more particularly, to backscatter - based positioning. Some features enable and provide improved communication, including reduced control overhead, efficient resource utilization, improved network access, improved ranging measurements, position determination, transmit / receive point (TRP) selection, reduced interference, or combinations thereof. Background Art

[0004] Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcasting, etc. These wireless networks can be multi - access networks capable of supporting multiple users by sharing available network resources. Such networks can be multi - access networks that communicate by sharing available network resources to support multiple users.

[0005] A wireless communication network may include several components. These components may include wireless communication devices, such as a base station (or Node B) that can support communication for multiple user equipments (UEs). The UEs can communicate with the base station via the downlink and the uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

[0006] The base station can send data and control information to the UE on the downlink, or receive data and control information from the UE on the uplink. On the downlink, the transmission from the base station may encounter interference due to transmissions from neighboring base stations or other radio frequency (RF) transmitters. On the uplink, the transmission from the UE may encounter interference from other UEs communicating with neighboring base stations or from uplink transmissions of other wireless RF transmitters. Such interference may degrade the performance on both the downlink and the uplink.

[0007] Due to the continuous growth in the demand for mobile broadband access, with more UEs accessing remote wireless communication networks and more short - range wireless systems deployed in the community, the likelihood of interference and congested networks is also increasing. Research and development continue to advance wireless technologies to not only meet the growing demand for mobile broadband access but also enhance and improve the user experience of mobile communication.

[0008] Radio Frequency Identification (RFID) systems and devices generally include a reader device, referred to as a reader, and one or more tag devices, such as RFID tag devices. Tag devices generally include a wireless microchip that is used to tag an object for automatic identification. However, as an illustrative non-limiting example, the use of tag devices has not been applied to current 3GPP technologies and Internet of Things (IoT) implementations that may include identification, monitoring, positioning, and tracking. Thus, the use of tag devices applied to current 3GPP technologies, such as coexistence with user equipment (UE) and infrastructure in the frequency bands for current 3GPP technologies, has not been established. Given the low power and limited processing capabilities of different types of tag devices, the integration of tag devices with 3GPP technologies presents various complexities and technical challenges, such as limiting network congestion, overhead, and interference associated with the use of tag devices leveraging 3GPP technologies. SUMMARY OF THE INVENTION

[0009] Some aspects of the present disclosure are summarized below to provide a basic understanding of the technologies discussed. This summary is not an exhaustive overview of all the expected features of the present disclosure and is neither intended to identify key or important elements of all aspects of the present disclosure nor to delineate the scope of any or all aspects of the present disclosure. The sole purpose of this summary of the invention is to present some concepts of one or more aspects of the present disclosure in a generalized form as a prelude to the more detailed embodiments that are presented later.

[0010] In one aspect of the present disclosure, a method for wireless communication is performed by a tag device. The method includes receiving a configuration signal that indicates a tag address of the tag device and a modulation scheme for generating a backscatter signal. The method further includes receiving a positioning reference signal (PRS) after receiving the configuration signal. The method further includes transmitting the backscatter signal based on the modulation scheme and the PRS.

[0011] In an additional aspect of the present disclosure, an apparatus includes at least one processor and a memory coupled to the at least one processor. The at least one processor is configured to receive a configuration signal that indicates a tag address of the tag device and a modulation scheme for generating a backscatter signal. The at least one processor is further configured to receive the PRS after receiving the configuration signal. The at least one processor is further configured to transmit the backscatter signal based on the modulation scheme and the PRS.

[0012] In an additional aspect of the present disclosure, an apparatus includes means for receiving a configuration signal that indicates a tag address of the tag device and a modulation scheme for generating a backscatter signal. The apparatus further includes means for receiving the PRS after receiving the configuration signal. The apparatus further includes means for transmitting the backscatter signal based on the modulation scheme and the PRS.

[0013] In an additional aspect of the present disclosure, a non-transitory computer-readable medium stores instructions that, when executed by a processor, cause the processor to perform operations. The operations include receiving a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The operations further include receiving a PRS after receiving the configuration signal. The operations also include transmitting the backscatter signal based on the modulation scheme and the PRS.

[0014] In an additional aspect of the present disclosure, a method for wireless communication is performed by a network entity. The method includes transmitting a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The method further includes transmitting a PRS after transmitting the configuration signal. The method also includes receiving the backscatter signal from the tag device based on the modulation scheme and the PRS.

[0015] In an additional aspect of the present disclosure, an apparatus includes at least one processor and a memory coupled to the at least one processor. The at least one processor is configured to transmit a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The at least one processor is further configured to transmit a PRS after transmitting the configuration signal. The at least one processor is also configured to receive the backscatter signal from the tag device based on the modulation scheme and the PRS.

[0016] In an additional aspect of the present disclosure, an apparatus includes means for transmitting a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The apparatus further includes means for transmitting a PRS after transmitting the configuration signal. The apparatus also includes means for receiving the backscatter signal from the tag device based on the modulation scheme and the PRS.

[0017] In an additional aspect of the present disclosure, a non-transitory computer-readable medium stores instructions that, when executed by a processor, cause the processor to perform operations. The operations include transmitting a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The operations further include transmitting a PRS after transmitting the configuration signal. The operations also include receiving the backscatter signal from the tag device based on the modulation scheme and the PRS.

[0018] The features and technical advantages of examples in accordance with the present disclosure have been outlined rather broadly above so that the detailed description below may be better understood. Additional features and advantages will be described hereinafter. The disclosed concepts and specific examples can be readily used as a basis for modifying or designing other structures for achieving the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics (both its organization and method of operation) of the concepts disclosed herein, as well as the associated advantages, will be better understood from the following description when considered in conjunction with the accompanying drawings. Each of the drawings provided is for the purpose of illustration and description and not as a definition of the limits of the claims.

[0019] While aspects and specific implementations are described herein by way of illustration of some examples, those skilled in the art will understand that additional specific implementations and use cases may arise in many different arrangements and scenarios. The innovations described herein can be implemented across many different platform types, devices, systems, shapes, sizes, packaging arrangements. For example, aspects and / or uses may be implemented via integrated chips and other non-module-component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). Although some examples may or may not be specifically directed to use cases or applications, applicability of various types of the described innovations may arise. The scope of specific implementations can range from chip-level or module components to non-module, non-chip-level implementations and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more aspects of the described innovations. In some practical environments, devices incorporating the described aspects and features may also necessarily include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily includes multiple components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). The innovations described herein are intended to be practiced in a variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc., having different sizes, shapes, and configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A further understanding of the nature and advantages of the present disclosure can be realized by reference to the following drawings. In the drawings, like components or features may have the same reference numeral. Additionally, various components of the same type can be distinguished by adding a dash and a second numeral used to differentiate between like components after the reference numeral. If only the first reference numeral is used in the specification, the description applies to any one of the like components having the same first reference numeral regardless of the second reference numeral.

[0021] Figure 1 is a block diagram illustrating details of an example wireless communication system according to one or more aspects.

[0022] Figure 2 is a block diagram illustrating examples of a base station and a user equipment (UE) according to one or more aspects.

[0023] Figure 3 is a block diagram illustrating an example wireless communication system supporting backscatter-based positioning according to one or more aspects.

[0024] Figure 4 is a ladder diagram illustrating an example of backscatter-based positioning according to one or more aspects.

[0025] Figure 5 is a conceptual diagram illustrating the timing of a wireless communication system supporting backscatter-based positioning according to one or more aspects.

[0026] Figure 6 is a conceptual diagram depicting interference at a transmit / receive point (TRP) in one or more aspects.

[0027] Figure 7 is a conceptual diagram illustrating the timing associated with backscatter-based positioning according to one or more aspects.

[0028] Figure 8 is a conceptual diagram illustrating the timing associated with backscatter-based positioning according to one or more aspects.

[0029] Figure 9 is a conceptual diagram illustrating the timing associated with backscatter-based positioning according to one or more aspects.

[0030] Figure 10 is a conceptual diagram illustrating the timing associated with backscatter-based positioning according to one or more aspects.

[0031] Figure 11 is a flowchart illustrating an example process supporting backscatter-based positioning according to one or more aspects.

[0032] Figure 12 is a block diagram of an example tag device supporting backscatter-based positioning according to one or more aspects.

[0033] Figure 13 is a flowchart illustrating an example process supporting backscatter-based positioning according to one or more aspects.

[0034] Figure 14 is a block diagram of an example network entity supporting backscatter-based positioning according to one or more aspects.

[0035] Like reference numerals and names in the various figures indicate like elements. Detailed Description

[0036] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to limit the scope of the disclosure. On the contrary, the detailed description includes specific details for providing a thorough understanding of the subject matter of the present invention. It will be apparent to those skilled in the art that these specific details are not required in every instance and that in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

[0037] The present disclosure provides systems, apparatuses, methods, and computer-readable media that support backscatter-based positioning. For example, the present disclosure describes positioning tag devices such as passive Internet of Things (IoT) devices via backscatter transmissions. By way of illustration, a network entity such as a transmit / receive point (TRP) may perform a positioning session (e.g., a ranging session) with a tag device. The network entity may send a configuration signal that indicates a tag address of the tag device (e.g., a tag identifier of the tag device or a group identifier associated with the tag device) and a modulation scheme for generating a backscatter signal. The modulation scheme may indicate a frequency shift parameter, a phase scrambling parameter, an on / off pattern, modulation data, or a combination thereof. The scrambling parameter may include or indicate a scrambling sequence ID for multiplexing data (e.g., modulation data or predefined data) in the code domain. The frequency shift parameter may include or indicate a frequency shift in the frequency domain. The on / off pattern may include or indicate a pattern or sequence for the tag device to perform backscatter operations or energy harvesting operations. In some embodiments, the configuration signal further includes an energy signal that is configured to be converted by the tag device into energy for energy harvesting by the tag device. After sending the configuration signal, the network entity may send a positioning reference signal (PRS) for the positioning session. The tag device may receive the PRS, generate a backscatter signal modulated based on the modulation scheme, and send the backscatter signal. The network entity receives the backscatter signal from the tag device based on the modulation scheme and the PRS. The network entity may correlate the backscatter signal and the PRS and determine a round-trip time (RTT) based on the correlation of the backscatter signal and the PRS. The position of the tag device may be determined based on the RTT. In some embodiments, the network entity identifies interference in the channel of the backscatter signal after sending the PRS. The interference may include self-interference, environmental interference, or a combination thereof. The network entity may update the modulation scheme based on the interference to cancel the interference.

[0038] Specific embodiments of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages or benefits. In some aspects, this disclosure provides techniques for supporting backscatter-based positioning. The described techniques facilitate determining the location (such as a two-dimensional or three-dimensional location) of tag devices (such as passive tag devices or semi-passive tag devices) with limited on-board power and computing resources by providing enhanced techniques for a network entity (such as a TRP) to perform RTT measurements. Specifically, the disclosed techniques facilitate the performance of RTT measurements even when performing positioning operations on tag devices with limited on-board power, limited computing resources, asynchronous operation with the TRP, or a combination thereof. These RTT measurements can then be used to determine the location of the tag device.

[0039] This disclosure generally relates to providing or participating in authorized shared access between two or more wireless devices in one or more wireless communication systems (also referred to as wireless communication networks). In various embodiments, the techniques and apparatus can be used in wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, fifth-generation (5G) or new radio (NR) networks (sometimes referred to as "5G NR" networks, systems, or devices), and other communication networks. As described herein, the terms "network" and "system" can be used interchangeably.

[0040] CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (W-CDMA) and Low Chip Rate (LCR). CDMA2000 covers the IS-2000, IS-95, and IS-856 standards.

[0041] For example, a TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). The 3rd Generation Partnership Project (3GPP) defines the standards for the GSM EDGE (Enhanced Data rates for GSM Evolution) Radio Access Network (RAN) (also known as GERAN). GERAN is the radio component of GSM / EDGE together with the network connecting base stations (such as the Ater and Abis interfaces) and base station controllers (the A interface, etc.). The radio access network represents the component of the GSM network through which telephone calls and packet data are routed from the Public Switched Telephone Network (PSTN) and the Internet to the subscriber mobile phone (also known as the user terminal or user equipment (UE)) and from the subscriber mobile phone to the PSTN and the Internet. The network of a mobile phone operator may include one or more GERANs, which may be coupled to the UTRAN in the case of a UMTS / GSM network. Additionally, the operator network may also include one or more LTE networks, or one or more other networks. Various different network types may use different Radio Access Technologies (RATs) and RANs.

[0042] An OFDMA network may implement radio technologies such as evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM, etc. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These various radio technologies and standards are known or under development. For example, 3GPP is a cooperation among telecommunication association groups aimed at defining globally applicable third-generation (3G) mobile phone specifications. 3GPP LTE is a 3GPP plan aimed at improving the UMTS mobile phone standard. 3GPP may define the specifications for next-generation mobile networks, mobile systems, and mobile devices. Certain aspects of the present disclosure may be described with reference to LTE, 4G, or 5G NR technologies; however, the description is not intended to be limited to a particular technology or application, and one or more aspects described with reference to one technology may be understood to be applicable to another technology. Additionally, one or more aspects of the present disclosure may relate to shared access to the radio spectrum between networks using different radio access technologies or radio air interfaces.

[0043] The 5G network is expected to have diverse deployments, diverse spectrums, and diverse services and devices enabled by a unified OFDM-based air interface. To achieve these goals, in addition to developing new radio technologies for the 5G NR network, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to provide coverage (1) to large-scale Internet of Things (IoT) with ultra-high density (e.g., about 1M nodes / km 2 ), ultra-low complexity (e.g., about 10s bits / sec), ultra-low power consumption (e.g., about 10+ year battery life), and deep coverage with the ability to reach challenging locations; (2) including mission-critical control with strong security to protect sensitive personal, financial, or classified information, ultra-high reliability (e.g., about 99.9999% reliability), ultra-low latency (e.g., about 1 millisecond (ms)), and users with a wide range of mobility or lack of mobility; and (3) providing coverage with enhanced mobile broadband (including extremely high capacity (e.g., about 10Tbps / km 2 ), extremely high data rates (e.g., multi-Gbps rates, 100+ Mbps user experience rate), and deep awareness with advanced discovery and optimization).

[0044] Devices, networks, and systems can be configured to communicate via one or more portions of the electromagnetic spectrum. The electromagnetic spectrum is typically subdivided into various categories, frequency bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). The frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, in various documents and articles, FR1 is typically (interchangeably) referred to as the "sub-6 GHz" band. Similar naming issues sometimes occur for FR2, and in documents and articles, FR2 is typically (interchangeably) referred to as the "millimeter wave" (mmWave) band, although it is different from the extremely high frequency (EHF) band (30 GHz to 300 GHz) identified by the International Telecommunication Union (ITU) as the "mmWave" band.

[0045] Taking the above aspects into account, unless otherwise specifically stated, it should be understood that if used in this document, terms such as "sub-6 GHz" can generally represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Additionally, unless otherwise specifically stated, it should be understood that if used in this document, terms such as "mmWave" can generally represent frequencies that can include mid-band frequencies, can be within FR2, or can be within the EHF band.

[0046] 5G NR devices, networks, and systems can be implemented to use waveform features based on optimized OFDM. These features can include scalable parameter sets and transmission time intervals (TTIs); a common flexible framework for efficiently multiplexing services and features using dynamic, low-latency time division duplex (TDD) designs or frequency division duplex (FDD) designs; and advanced radio technologies such as massive multiple-input multiple-output (MIMO), robust mmWave transmission, advanced channel decoding, and device-centric mobility. The scalability of parameter sets and the scaling of subcarrier spacing in 5G NR can efficiently address the operation of various services across different spectrums and different deployments. For example, in various outdoor and macro coverage deployments with less than 3 GHz FDD or TDD implementations, the subcarrier spacing may occur at 15 kHz, such as for bandwidths exceeding 1 MHz, 5 MHz, 10 MHz, 20 MHz, etc. For other various outdoor and small cell coverage deployments with TDD greater than 3 GHz, the subcarrier spacing may occur at 30 kHz for 80 MHz / 100 MHz bandwidths. For other various indoor broadband implementations using TDD in the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur at 60 kHz for 160 MHz bandwidths. Finally, for various deployments with transmission via mmWave components under TDD at 28 GHz, the subcarrier spacing can occur at 120 kHz for 500 MHz bandwidths.

[0047] The scalable parameter sets of 5G NR facilitate scalable TTIs for diverse latency and quality of service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs allows transmissions to start at symbol boundaries. 5G NR also anticipates self-contained integrated subframe designs, where uplink or downlink scheduling information, data, and acknowledgments are located in the same subframe. Self-contained integrated subframes support communication in unlicensed or contention-based shared spectrums, and adaptive uplink or downlink can be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet current traffic demands.

[0048] For clarity, certain aspects of the devices and technologies may be described below with reference to example 5G NR implementations or in a 5G-centric manner, and 5G terminology may be used as illustrative examples in parts of the description below; however, the description is not intended to be limited to 5G applications.

[0049] In addition, it should be understood that in operation, a wireless communication network adapted according to the concepts herein can operate using any combination of licensed or unlicensed spectrum depending on load and availability. Thus, it will be apparent to those of ordinary skill in the art that the systems, apparatuses, and methods described herein can be applied to other communication systems and applications beyond the specific examples provided.

[0050] While aspects and specific implementations are described in this application by way of illustration of some examples, those skilled in the art will understand that additional specific implementations and use cases may arise in many different arrangements and scenarios. The innovations described herein can be implemented across many different platform types, devices, systems, shapes, sizes, packaging arrangements. For example, a specific implementation or use can be implemented via an integrated chip or other non-module-component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail or point-of-purchase devices, medical devices, AI-enabled devices, etc.). Although some examples may or may not specifically be directed to a use case or application, applicability of various types of the described innovations can occur. The scope of specific implementations can range from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems that incorporate one or more of the described aspects. In some practical environments, devices that incorporate the described aspects and features may also necessarily include additional components and features for implementing and practicing the claimed and described aspects. It is intended that the innovations described herein be implemented in a wide variety of specific implementations of different sizes, shapes, and configurations, including both large and small devices, chip-level components, multi-component systems (e.g., radio frequency (RF) chains, communication interfaces, processors), distributed arrangements, end-user devices, etc.

[0051] Figure 1 is a block diagram illustrating details of an example wireless communication system according to one or more aspects. The wireless communication system can include a wireless network 100. The wireless network 100 can include, for example, a 5G wireless network. As those skilled in the art will recognize, Figure 1 the components that appear in are likely to have related corresponding components in other network arrangements, including, for example, cellular-style network arrangements as well as non-cellular-style network arrangements (e.g., device-to-device or peer-to-peer or ad-hoc network arrangements, etc.).

[0052] Figure 1The illustrated wireless network 100 includes a number of base stations 105 and other network entities. A base station can be a station that communicates with a UE and can also be referred to as an evolved Node B (eNB), a next-generation eNB (gNB), an access point, etc. Each base station 105 can provide communication coverage for a specific geographical area. In 3GPP, the term "cell" can refer to the specific geographical coverage area of a base station or the base station subsystem serving that coverage area, depending on the context in which the term is used. In a particular implementation of the wireless network 100 herein, the base stations 105 can be associated with the same operator or different operators (e.g., the wireless network 100 can include multiple operator wireless networks). Additionally, in a particular implementation of the wireless network 100 herein, the base stations 105 can use one or more frequencies in the same frequency as an adjacent cell (e.g., one or more frequency bands in licensed spectrum, unlicensed spectrum, or a combination thereof) to provide wireless communication. In some examples, a separate base station 105 or UE 115 can be operated by more than one network operating entity. In some other examples, each base station 105 and UE 115 can be operated by a single network operating entity.

[0053] The base station can provide communication coverage for macro cells or small cells (such as pico cells or femto cells) or other types of cells. A macro cell generally covers a relatively large geographical area (e.g., with a radius of several kilometers) and can allow unrestricted access by UEs having a service subscription with the network provider. A small cell (such as a pico cell) generally covers a relatively small geographical area and can allow unrestricted access by UEs having a service subscription with the network provider. A small cell (such as a femto cell) generally also covers a relatively small geographical area (e.g., a home) and can provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the home, etc.) in addition to unrestricted access. The base station for a macro cell can be referred to as a macro base station. The base station for a small cell can be referred to as a small cell base station, a pico base station, a femto base station, or a home base station. In Figure 1 the example shown, base stations 105d and 105e are conventional macro base stations, while base stations 105a to 105c are macro base stations implemented using one of 3-dimensional (3D), full-dimensional (FD), or massive MIMO. Base stations 105a to 105c utilize their higher-dimensional MIMO capabilities to employ 3D beamforming in elevation and azimuth beamforming to increase coverage and capacity. Base station 105f is a small cell base station, which can be a home node or a portable access point. A base station can support one or more (e.g., two, three, four, etc.) cells.

[0054] The wireless network 100 may support synchronous or asynchronous operations. For synchronous operations, the base stations may have similar frame timings, and transmissions from different base stations may be approximately aligned in time. For asynchronous operations, the base stations may have different frame timings, and transmissions from different base stations may not be aligned in time. In some cases, the network may be enabled or configured to handle dynamic switching between synchronous and asynchronous operations.

[0055] UEs 115 are scattered throughout the wireless network 100, and each UE can be stationary or mobile. It should be understood that although in the standards and specifications promulgated by 3GPP, mobile devices are generally referred to as UEs, such devices may additionally or otherwise be referred to by those skilled in the art as mobile stations (MSs), subscriber stations, mobile units, subscriber units, radio units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals (ATs), mobile terminals, wireless terminals, remote terminals, cell phones, terminals, user agents, mobile clients, clients, gaming devices, augmented reality devices, vehicle components, vehicle devices, or vehicle modules or some other suitable term. In this document, a "mobile" device or UE does not necessarily have the ability to move and can be stationary. Some non-limiting examples of mobile devices may include specific implementations such as one or more UEs 115, including mobile phones, cellular phones, smart phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, laptop computers, personal computers (PCs), notebooks, netbooks, smartbooks, tablet computers, and personal digital assistants (PDAs). Mobile devices can additionally be IoT or "Internet of Everything" (IoE) devices, such as cars or other transportation vehicles, satellite radios, global positioning system (GPS) devices, global navigation satellite system (GNSS) devices, logistics controllers, drones, multi-rotor helicopters, quad-rotor helicopters, smart energy or security devices, solar panels or solar cell arrays, city lighting, tap water, or other infrastructure; industrial automation and enterprise equipment; consumer and wearable devices, such as glasses, wearable cameras, smart watches, health or fitness trackers, mammalian implantable devices, gesture tracking devices, medical devices, digital audio players (e.g., MP3 players), cameras, gaming consoles, etc.; and digital home or smart home devices, such as home audio, video, and multimedia devices, appliances, sensors, vending machines, smart lighting, home security systems, smart meters, etc. In one aspect, a UE can be a device that includes a universal integrated circuit card (UICC). In another aspect, a UE can be a device that does not include a UICC. In some aspects, a UE that does not include a UICC can also be referred to as an IoE device. Figure 1The illustrated specific implementations of UEs 115a through 115d are examples of mobile smartphone-type devices that access the wireless network 100. The UEs can also be machines specifically configured for connectivity communications, including machine type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc. Figure 1 The illustrated UEs 115e through 115k are examples of various machines that access the wireless network 100 and are configured for communications.

[0056] A mobile device such as UE 115 can be capable of communicating with any type of base station, whether it is a macro base station, a pico base station, a femto base station, a relay station, etc. In Figure 1 it, the communication link (represented as lightning) indicates a wireless transmission between the UE and the serving base station (which is the base station designated to serve the UE on the downlink or uplink), a desired transmission between base stations, and a backhaul transmission between base stations. The UE can operate as a base station or other network node in some scenarios. The backhaul communication between the base stations of the wireless network 100 can be carried out using a wired or wireless communication link.

[0057] In operation, at the wireless network 100, base stations 105a through 105c use 3D beamforming and collaborative spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity, to serve UEs 115a and 115b. Macro base station 105d performs backhaul communication with base stations 105a through 105c and the small cell (base station 105f). Macro base station 105d also transmits multicast services subscribed to and received by UEs 115c and 115d. Such multicast services can include mobile TV or streaming video, or can include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or Gray alerts.

[0058] The wireless network 100 in a specific implementation supports mission-critical communications with ultra-reliable and redundant links for mission-critical devices such as this UE 115e acting as a drone. The redundant communication links with the UE 115e include links from macro base stations 105d and 105e and small cell base station 105f. Other machine type devices such as UE 115f (thermometer), UE 115g (smart meter), and UE 115h (wearable device) can communicate directly with base stations such as small cell base station 105f and macro base station 105e through the wireless network 100, or in a multi-hop configuration by communicating with another user equipment that relays its information to the network. For example, UE 115f communicates temperature measurement information to smart meter UE 115g, and then reports it to the network through small cell base station 105f. The wireless network 100 can also provide additional network efficiency through dynamic, low-latency TDD communication or low-latency FDD communication (such as in a vehicle-to-vehicle (V2V) mesh network between UEs 115i to 115k communicating with macro base station 105e).

[0059] The base stations 105 can communicate with the core network 130 and with each other. For example, the base stations 105 can interface with the core network 130 through a backhaul link 132 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 can communicate with each other directly (e.g., directly between base stations 105) or indirectly (e.g., via the core network 130) through a backhaul link (e.g., via X2, Xn, or other interfaces).

[0060] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC), which can include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME can manage non-access stratum (e.g., control plane) functions such as the mobility, authentication, and bearer management of UEs 115 served by base stations 105 associated with the EPC. User IP packets can be relayed through the S-GW, which itself can be connected to the P-GW. The P-GW can provide IP address allocation and other functions. The P-GW can be connected to the network operator's IP services. The operator's IP services can include access to the Internet, intranet, IP multimedia subsystem (IMS), or packet-switched (PS) streaming services.

[0061] In some specific implementations, the core network 130 includes or is coupled to a Location Management Function (LMF) 131, which is an entity in the 5G core network (5GC) that supports various functionalities such as managing support for different location services for one or more UEs. For example, the LMF 131 may include one or more servers, such as multiple distributed servers. The base station 105 may forward location messages to the LMF 131 and may communicate with the LMF via the NR Positioning Protocol A (NRPPa). The LMF 131 is configured to control the positioning parameters of the UE 115, and the LMF 131 may provide information to the base station 105 and the UE 115 such that actions can be taken at the UE 115. In some specific implementations, the UE 115 and the base station 105 are configured to communicate with the LMF 131 via the Access and Mobility Management Function (AMF).

[0062] A tag device system generally includes a tag device 120 and a reader device 121. The tag device 120 includes a Radio Frequency Identification (RFID) device or tag, which includes a wireless microchip for tagging an object for automatic object identification. The reader device 121, such as an RFID reader, may be configured to send electromagnetic signals to other devices such as the tag device 120. The reader device 121 may include one or more processors and a memory and is generally capable of processing data. Additionally, the reader device 121 generally includes one or more transmitters and receivers. During typical operation, the reader device 121 may be configured to send signals that can be received by the tag device 120 and to receive and process signals from the tag device 120 in response to the sent signals.

[0063] Tag devices such as the tag device 120 are classified based on their function or capabilities. For example, depending on the function or capabilities of the tag device 120, the tag device 120 may be classified as one of a passive tag, a semi-passive tag, and an active tag. Thus, the tag device 120 may correspond to a passive tag, a semi-passive tag, or an active tag.

[0064] Passive tags typically lack a power source, harvest energy from ambient electromagnetic signals, and have limited computing capabilities, often lacking components for signal processing such as analog-to-digital converters (ADCs) and digital-to-analog converters (DACs). Due to the lack of signal processing capabilities in passive tags, passive tags typically include simple circuits to reflect received electromagnetic signals back into the environment in the form of backscatter transmissions. For example, a reader device 121 may transmit an electromagnetic signal, and a passive tag such as a tag device 120 may receive the electromagnetic signal and at least partially reflect the electromagnetic signal in the form of a backscatter signal. Specifically, if the tag device 120 is a passive tag, the tag device 120 may include circuitry to at least partially reflect the unabsorbed portion of the electromagnetic signal received from the surrounding environment, such as the electromagnetic signal transmitted by the reader device 121 in the form of a backscatter transmission.

[0065] Semi-passive tags typically include an on-board power source to power on-board electronic components. Generally speaking, semi-passive tags typically have greater computing power than passive tags. Additionally, semi-passive tags may have a limited on-board power source; however, semi-passive tags typically transmit signals via backscatter transmission, as explained above in the context of passive tags.

[0066] Active tags typically include an on-board power source and greater computing capabilities than passive or semi-passive tags. Additionally, unlike passive and semi-passive tags that typically cannot transmit unless a reader device such as reader device 121 is in proximity to them, active tags are capable of transmitting regardless of the proximity of the reader device. Active tag devices typically include signal processing functions such as ADCs, DACs, etc. Additionally, active tags typically include a power source and are capable of active transmission. Specifically, unlike passive and semi-passive tags that generate a backscatter signal by at least partially reflecting a transmission received from a reader device (e.g., reader device 121), active tags are capable of transmitting independently of signals received from another device such as reader device 121.

[0067] Additionally, a tagging device such as tagging device 120 typically includes a tag identifier that uniquely identifies the tagging device. Thus, a tagging device such as tagging device 121 can respond to a transmission received from reader device 121 at the tagging device by including its unique tag identifier. If tagging device 120 corresponds to a passive tag or a semi-passive tag, tagging device 120 can be configured to at least partially reflect the transmission received from reader device 121 in the form of a backscatter signal that can be read by reader device 121. Although an active tag can process the transmitted signal received from reader device 121, in some embodiments, the active tagging device can also partially reflect the received signal as a backscatter signal, or can independently transmit a signal to reader device 121 in response to the signal received from reader device 121.

[0068] A tagging device system including tagging device 120 and reader device 121 can be deployed to locate an object associated with tagging device 120. For example, tagging device 120 can be attached to an object, and reader device 121 can be configured to identify the location (e.g., two-dimensional location, three-dimensional location) of the object to which tagging device 120 is attached by using backscatter-based positioning. Thus, the tagging device system can be deployed in a wide range of applications where precise and accurate object positioning is implemented. As illustrative non-limiting examples, these applications can include self-checkout, medical applications such as monitoring a patient's compliance with medical instructions, and law enforcement and security applications.

[0069] Figure 2 is a block diagram illustrating an example of base station 105 and UE 115 according to one or more aspects. Base station 105 and UE 115 can be Figure 1 any one of the base stations and one of the UEs among the base stations in. For a restricted association scenario (as described above), base station 105 can be Figure 1 the small cell base station 105f in, and UE 115 can be UE 115c or 115d operating in the service area of base station 105f, which will be included in the list of accessible UEs of small cell base station 105f for accessing small cell base station 105f. Base station 105 can also be some other type of base station. As Figure 2 shown, base station 105 can be equipped with antennas 234a to 234t, and UE 115 can be equipped with antennas 252a to 252r for facilitating wireless communication.

[0070] At base station 105, transmit processor 220 may receive data from data source 212 and receive control information from controller 240, such as a processor. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ (automatic repeat request) indicator channel (PHICH), a physical downlink control channel (PDCCH), an enhanced physical downlink control channel (EPDCCH), an MTC physical downlink control channel (MPDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. Additionally, transmit processor 220 may process (e.g., encode and symbol map) the data and control information respectively to obtain data symbols and control symbols. Transmit processor 220 may also generate reference symbols for, e.g., a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), as well as cell-specific reference signals. Transmit (TX) MIMO processor 230 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, or reference symbols (if applicable) and may provide an output symbol stream to modulators (MOD) 232a through 232t. For example, the spatial processing performed on the data symbols, control symbols, or reference symbols may include precoding. Each modulator 232 may process the corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Additionally or alternatively, each modulator 232 may process the output sample stream (e.g., perform analog-to-digital conversion, amplification, filtering, and upconversion on it) to obtain a downlink signal. The downlink signals from modulators 232a through 232t may be transmitted via antennas 234a through 234t respectively.

[0071] At UE 115, antennas 252a through 252r may receive the downlink signals from base station 105 and may provide the received signals to demodulators (DEMOD) 254a through 254r respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the corresponding received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain the received symbols. MIMO detector 256 may obtain the received symbols from demodulators 254a through 254r, perform MIMO detection on the received symbols when needed, and provide the detected symbols. Receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide the decoded data for UE 115 to data sink 260, and provide the decoded control information to controller 280, such as a processor.

[0072] On the uplink, at the UE 115, the transmit processor 264 may receive and process data from the data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from the controller 280 (e.g., for the Physical Uplink Control Channel (PUCCH)). Additionally, the transmit processor 264 may also generate reference symbols for reference signals. The symbols from the transmit processor 264 may be pre-coded by the TX MIMO processor 266 when needed, further processed by the modulators 254a through 254r (e.g., for SC-FDM, etc.), and transmitted to the base station 105. At the base station 105, the uplink signals from the UE 115 may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 when needed, and further processed by the receive processor 238 to obtain the decoded data and control information transmitted by the UE 115. The receive processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller 240.

[0073] The controllers 240 and 280 may direct operations at the base station 105 and the UE 115, respectively. The controller 240 or other processors and modules at the base station 105, or the controller 280 or other processors and modules at the UE 115, may execute or direct the execution of various processes for the techniques described herein, such as executing or directing Figure 11 and Figure 13 the execution shown or other processes for the techniques described herein. The memories 242 and 282 may store data and program codes for the base station 105 and the UE 115, respectively. The scheduler 244 may schedule the UE for data transmission on the downlink or uplink.

[0074] In some cases, UE 115 and base station 105 may operate in a shared radio spectrum band, which may include licensed or unlicensed (e.g., contention-based) spectrum. In the unlicensed frequency portion of the shared radio spectrum band, UE 115 or base station 105 may traditionally perform a medium sensing process to compete for access to the spectrum. For example, UE 115 or base station 105 may perform a listen-before-talk or listen-before-transmit (LBT) process (such as clear channel assessment (CCA)) before communication to determine whether the shared channel is available. In some implementations, CCA may include an energy detection process to determine whether there is any other active transmission. For example, a device may infer that a change in the received signal strength indicator (RSSI) of a power meter indicates that the channel is occupied. In particular, signal power concentrated in a certain bandwidth and exceeding a predetermined noise floor may indicate another wireless transmitter. CCA may also include the detection of a specific sequence indicating the use of the channel. For example, another device may transmit a specific preamble before transmitting a data sequence. In some cases, the LBT process may include a wireless node adjusting its own backoff window based on the amount of energy detected on the channel or acknowledgment / negative acknowledgment (ACK / NACK) feedback for its own transmitted packets (as an indication of a collision).

[0075] Figure 3 is a block diagram of an example wireless communication system 300 that supports backscatter-based positioning in accordance with one or more aspects. In some examples, wireless communication system 300 may implement aspects of wireless network 100. Wireless communication system 300 includes tag device 120 and TRP 340. Although described as TRP 340, in other implementations, TRP 340 may include or be another device, such as a network entity (e.g., reader device 121, base station 105, UE 115, etc.). Although one TRP and one tag device are illustrated, in some other implementations, wireless communication system 300 may generally include additional TRPs, additional tag devices, or combinations thereof.

[0076] Tag device 120 may be an RFID tag device. Additionally, tag device 120 may be a passive tag without a power source and with limited computing capabilities, a semi-passive tag with a limited power source and computing capabilities equal to or greater than those of a passive tag device, or an active tag with a power source and computing capabilities equal to or greater than those of a semi-passive tag device.

[0077] The tag device 120 may include various components (such as structural hardware components) for performing one or more functions described herein. For example, these components may include a circuit 351, a transmitter 356, and a receiver 358. As a non-limiting example, the circuit 351 may include or correspond to an energy harvesting circuit, a microcontroller, one or more processors, a memory, an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), or any combination thereof. The circuit 351 may depend on whether the tag device 120 is a passive tag, a semi-passive tag, or an active tag.

[0078] The transmitter 356 is configured to send one or more signals to one or more other devices (e.g., one or more TRPs or reader 121), and the receiver 358 is configured to receive one or more signals from one or more other devices (e.g., TRP 340, reader 121, core network 130). For example, the transmitter 356 may send a backscatter signal 376 to one or more TRPs (e.g., TRP 340), and the receiver 358 may receive a positioning reference signal 374 from one or more TRPs (e.g., TRP 340). In some embodiments, the transmitter 356 and the receiver 358 may be integrated in one or more transceivers. Additionally or alternatively, the transmitter 356 or the receiver 358 may include or correspond to one or more components of the tag device 120.

[0079] The tag device 120 may include one or more components as described herein with reference to the tag device 120. In some embodiments, the tag device 120 is a tag device with 3GPP capabilities, a tag device with LTE capabilities, a tag device with 5G capabilities, a tag device with 6G capabilities, or a combination thereof.

[0080] The TRP 340 may include various components (such as structural, hardware components) for performing one or more functions described herein. For example, these components may include one or more processors 302 (collectively referred to hereinafter as "processor 302"), one or more memory devices 304 (collectively referred to hereinafter as "memory 304"), one or more transmitters 316 (collectively referred to hereinafter as "transmitter 316"), and one or more receivers 318 (collectively referred to hereinafter as "receiver 318"). In some embodiments, the TRP 340 may include an interface (e.g., a communication interface) that includes a transmitter 316, a receiver 318, or a combination thereof. The processor 302 may be configured to execute instructions 305 stored in the memory 304 to perform the operations described herein. In some embodiments, the processor 302 includes or corresponds to one or more of a receiving processor 238, a transmitting processor 220, and a controller 240, and the memory 304 includes or corresponds to a memory 242.

[0081] Memory 304 includes or is configured to store instructions 305 and information 306. The information 306 may include PRS information 307 and tag device information 309.

[0082] The PRS information 307 includes information for the TRP 340 to generate positioning reference signals (PRSs) 374. For example, the PRS information 307 may include one or more parameters such as timing information, sequences corresponding to the PRSs 374 (e.g., wideband sequences, code division multiple access pseudo-random (CDMA-PN) sequences), an indication of whether the PRSs 374 are periodic, the period of the PRSs 374, or any combination thereof. Additionally or alternatively, the one or more parameters may include a repetition rate, a bandwidth configuration, a comb pattern configuration, or any combination thereof. The repetition rate may include or indicate the number of times the PRSs are transmitted within a certain time period. The comb pattern may include or indicate configurable resource block allocations.

[0083] The tag device information 309 may include or correspond to information about one or more tag devices such as the tag device 120. For example, the tag device information 309 may include the tag address of the tag device 120 (corresponding to the tag address 390), the modulation scheme for generating the backscatter signal 376 by the tag device 120 (corresponding to the modulation scheme 392), or a combination thereof. The tag address may indicate the tag identifier of the tag device 120, the group identifier associated with the tag device 120, or a combination thereof. The modulation scheme may indicate a frequency shift parameter (e.g., whereby the tag device 120 may be configured to shift the frequency of the backscatter signal 376), a phase scrambling parameter (whereby the tag device 120 may be configured to scramble the phase of the backscatter signal 376), an on / off mode, modulation data (for modulating the backscatter signal), or a combination thereof. The on / off mode may indicate one or more transitions of the tag device from a first state to a second state or from the second state to the first state. The first state may correspond to a backscatter transmission state (e.g., during which the tag device 120 is configured to transmit the backscatter signal 376), and the second state may correspond to an energy harvesting state (e.g., during which the tag device 120 is configured to generate energy from the backscatter signal 376).

[0084] Additionally or alternatively, the tag device information 309 may include tag type, bandwidth, PRS slot periodicity, sensitivity, group delay (e.g., tag delay), or a combination thereof. The tag type may correspond to whether the tag device (e.g., tag device 120) is a passive tag, a semi-passive tag, or an active tag. The bandwidth may correspond to the bandwidth over which the tag device 120 is capable of communicating. The PRS slot periodicity may correspond to the time frame during which the tag device 120 expects to receive the PRS 374 or how often it receives the PRS 374. The sensitivity may correspond to the sensitivity of the tag device 120 to the PRS 374, such as the transmit power of the PRS, the distance from the TRP at which the tag device 120 can successfully receive the signal, or a combination thereof. The group delay or tag processing delay may correspond to the amount of time that the tag device 120 takes to process the PRS 374 and generate a backscatter signal 376 in response to the reception or PRS 374 at the tag device 120. In other words, the tag delay such as radio frequency (RF) group delay may include or be based on one or more components of the tag device (e.g., circuit 351, transmitter 356, receiver 358, or a combination thereof). The one or more components are configured to: receive a positioning reference signal; generate a backscatter signal based on the positioning reference signal; and transmit the backscatter signal. In some embodiments, the tag delay is the amount of time between the tag device 120 receiving the positioning reference signal and transmitting the backscatter signal based on the received positioning reference signal.

[0085] The measurement information 310 includes or corresponds to the propagation time associated with the backscatter signal 376. For example, when the TRP 340 is configured as a Tx TRP, the measurement information 310 may include the transmit time of the PRS 374, the receive time of the backscatter signal 376, the amount of time elapsed from the transmit of the PRS 374 to the receive of the backscatter signal 376, or a combination thereof. In some embodiments, when the TRP 340 is configured as an Rx TRP, the measurement information 310 may include the receive time of the PRS 374, the receive time of the backscatter signal 376, the amount of time elapsed from the receive of the PRS 374 to the receive of the backscatter signal 376, or a combination thereof. The TRP 340 may be configured to generate a measurement report based on the measurement information 310.

[0086] The transmitter 316 is configured to send reference signals, control information, and data to one or more other devices, and the receiver 318 is configured to receive reference signals, synchronization signals, control information, and data from one or more other devices. For example, the transmitter 316 may send signaling, control information, and data to the core network 130, another TRP, or a network entity, and the receiver 318 may receive signaling, control information, and data from the core network, another TRP, or a network entity. Additionally or alternatively, the transmitter 316 may send positioning reference signals (e.g., 374), and the receiver 318 may receive backscatter signals (e.g., 376). In some embodiments, the transmitter 316 and the receiver 318 may be integrated in one or more transceivers. Additionally or alternatively, the transmitter 316 or the receiver 318 may include or correspond to one or more components as described for the UE 115 or the base station 105 in reference Figure 2 . In some embodiments, the transmitter 316 and the receiver 318 may be configured to operate in full-duplex mode.

[0087] In some embodiments, the TRP 340 may include one or more antenna arrays. The antenna array may include a plurality of antenna elements configured to perform wireless communication with other devices (such as with the core network 130). In some embodiments, the antenna array may be configured to perform wireless communication using different beams (also referred to as antenna beams). The beams may include Tx beams and Rx beams. By way of illustration, the antenna array may include a plurality of independent sets (or subsets) of antenna elements (or a plurality of independent antenna arrays), and each set of antenna elements of the antenna array may be configured to communicate using a different corresponding beam, which may have a different corresponding direction from other beams. For example, the first set of antenna elements of the antenna array may be configured to communicate via a first beam having a first direction, and the second set of antenna elements of the antenna array may be configured to communicate via a second beam having a second direction. In other embodiments, the antenna array may be configured to communicate via more than two beams. Alternatively, one or more sets of antenna elements of the antenna array may be configured to concurrently generate multiple beams, such as using multiple RF chains. Each individual set (or subset) of antenna elements may include a plurality of antenna elements, such as two antenna elements, four antenna elements, ten antenna elements, twenty antenna elements, or any other number greater than two. Although described as an antenna array, in other embodiments, the antenna array may include or correspond to a plurality of antenna panels, and each antenna panel may be configured to communicate using a different corresponding beam. In some embodiments, the TRP 340 may be configured as or include a reader device, such as an RFID reader device. The TRP 340 may be configured to operate asynchronously with the tag device 120.

[0088] In some specific implementations, the wireless communication system 300 implements a 5G NR network. For example, the wireless communication system 300 may include multiple 5G-capable UEs 115 and multiple 5G-capable base stations 105, such as UEs and base stations configured to operate according to a 5G NR network protocol such as defined by 3GPP. In some other specific implementations, the wireless communication system 300 implements a 6G network. The present disclosure embodies use cases of interest that are not necessarily embodied elsewhere in 3GPP, such as identification, tracking, monitoring, and coexistence with UEs and infrastructure in the frequency bands of current 3GPP technologies.

[0089] In some specific implementations, the location of the tag device 120 may be determined by a network entity (e.g., the TRP 340 or the LMF 131) based on one or more measurement reports generated by one or more TRPs such as the TRP 340. The TRP 340 may generate a measurement report based on measurements such as round-trip time (RTT) measurements performed by one or more TRPs such as the TRP 340. Determining the location of the tag device 120 may include calculating time of arrival (TOA), time difference of arrival (TDOA), angle of arrival (AoA), or any combination thereof. Additionally, the LMF 131 may be configured to send location data indicating the location of the tag device 120.

[0090] During operation of the wireless communication system 300, the TRP 340 may send a configuration signal 372 that indicates the tag address 390 of the tag device 120, the modulation scheme 392 for the tag device 120 to generate the backscatter signal 376, or a combination thereof. The tag address 390 may indicate the tag identifier of the tag device 120, the group identifier associated with the tag device 120, or a combination thereof. The modulation scheme 392 may indicate a frequency shift parameter, a phase scrambling parameter, an on / off mode, modulation data, or a combination thereof. In some specific implementations, the configuration signal 372 is a two-part signal including a first component and a second component, the first component corresponding to an energy signal configured to supply energy to the tag device 120, and the second component corresponding to tag configuration data. The tag configuration data may include or correspond to the tag address 390 and the modulation scheme 392.

[0091] The tag device 120 may receive the configuration signal 372 and may initiate processing of the configuration signal 372. In response to determining that the tag address 390 corresponds to the tag device 120, the tag device 120 may generate the backscatter signal 376 based on the modulation scheme 392. However, if the tag device 120 determines that the tag address 390 does not correspond to the tag device 120, the tag device 120 may ignore the configuration signal 372.

[0092] In some specific implementations, the configuration signal 372 can be a binary signal that has a first energy signal component and a second configuration component that includes the tag address 390 and the modulation scheme 392. In such a case, after receiving the configuration signal 372, the tag device can be configured to generate (e.g., extract) energy based on the energy signal and can process one or more of the tag address 390 and the modulation scheme 392 as previously described herein.

[0093] The TRP 340 can send the PRS 374 after sending the configuration signal 372. The TRP 340 can receive the backscatter signal 376 from the tag device 120 based on the modulation scheme 392 included in the configuration signal 372. For example, in response to receiving the PRS 374 at the tag device 120, the tag device 120 can be configured to generate and send the backscatter signal 376 according to the modulation scheme 392.

[0094] The tag device 120 can receive the PRS 374 after receiving the configuration signal 372. Thereafter, the tag device 120 can send the backscatter signal 376 based on the modulation scheme 392 and the PRS 374. In some specific implementations, the sending of the backscatter signal 376 occurs after the end of a tag processing delay period, such as a time frame during which the tag device 120 processes the PRS 374 and the modulation scheme 392 to generate the backscatter signal 376. In some specific implementations, the tag device 120 modulates the PRS 374 with modulation data based on the modulation scheme 392 to generate the backscatter signal 376. The modulation data can include or correspond to the data included in the modulation scheme 392.

[0095] The TRP can receive the backscatter signal 376 and correlate the backscatter signal 376 with the PRS 374, as further explained herein at least with reference to Figure 6 Based on correlating the backscatter signal 376 with the PRS 374, the TRP 340 can determine the RTT of the PRS 374 and the backscatter signal 376. The RTT can include or correspond to the sum of a first amount of time for the PRS 374 to travel from the TRP 340 to the tag device 120 and a second amount of time for the backscatter signal 376 to travel from the tag device 120 to the TRP 340.

[0096] In some specific implementations, a TRP such as TPR 340 transmits a configuration signal such as configuration signal 372, and the configuration signal indicates a modulation scheme such as modulation scheme 392 for generating a backscatter signal 376. The tag device 120 may receive the configuration signal and may process modulation data corresponding to or included in the modulation scheme. For example, the modulation data may include a symbol pattern that will be modulated by the tag device onto the PRS (e.g., PRS 374) to generate a backscatter signal such as backscatter signal 376. In this way, when the backscatter signal is reflected back to the TRP, the TRP may detect the symbol pattern corresponding to the modulation data.

[0097] In some specific implementations, after transmitting the PRS 374, the TRP receives an unmodulated reflected backscatter signal from the tag device, and the TRP may use the unmodulated reflected backscatter signal to evaluate self-interference, environmental interference, or a combination thereof in the reflected but unmodulated backscatter signal. However, after a time delay at the tag device (which may be attributable to processing the PRS in some cases), the tag device may modulate the PRS using the modulation data and may reflect the modulated PRS corresponding to the backscatter signal. The TRP may receive the backscatter signal (e.g., the PRS modulated with the modulation data), and may correlate the transmitted PRS with the received backscatter signal to determine the RTT corresponding to the transmitted PRS and the received backscatter signal. For example, the correlation may include comparing, by the TRS, a first time of one or more symbols of the transmitted PRS with a second time of one or more symbols of the received backscatter signal (e.g., the PRS modulated with the modulation data). Based on the foregoing comparison, the TRP may be configured to determine the RTT. The RTT may correspond to the sum of a first amount of time during which the PRS travels from the TRP to the tag device and a second amount of time during which the backscatter signal (e.g., the PRS modulated with the modulation data) travels from the tag device to the TRP. In this way, even if the TRP and the tag device operate asynchronously with respect to each other, the TRP may determine the RTT.

[0098] In some specific implementations, to determine the RTT, the TRP 340 detects a backscatter signal such as backscatter signal 376 that includes or corresponds to the PRS modulated with the modulation data, and compares a first time when the TRP 340 receives the backscatter signal with a second time when the TRP 340 transmits the PRS to determine the RTT. Specifically, mathematically, the PRS (e.g., PRS374) may correspond to the signal c(t). The backscatter signal received at the TRP such as TRP 340 (e.g., the PRS modulated with the modulation data) may correspond to c(t - t c )b(t - t b )), where c(t - t c ) corresponds to the PRS component of the backscatter signal, and b(t - tb ) Corresponds to the modulation data modulated onto the PRS. The backscatter signal received at the TRP (e.g., TRP 340), such as backscatter signal 376, can mathematically correspond to r(t) = h c c(t) + h b c(t - t c )b(t - t b ) + ∑ i h i c(t - t i ), where r(t) represents the backscatter signal received at the TRP, h c represents the self-interference channel gain, h b represents the backscatter channel gain, t c includes or corresponds to the RTT, and t b includes or corresponds to an unknown time delay associated with the modulation data. In the foregoing formula, h c c(t) may include or correspond to the self-interference attributable to the transmission of the PRS and experienced by the TRP when in the Rx mode, ∑ i h i c(t - t i ) may include or correspond to the interference attributable to environmental factors such as objects near the tag device and experienced by the TRP when in the Rx mode. As further described herein, the disclosed techniques facilitate the determination of t c .

[0099] As described with reference to Figure 3 , the present disclosure provides techniques for supporting backscatter-based positioning of one or more tag devices such as tag device 120. The described techniques facilitate the determination of the location (such as a two-dimensional or three-dimensional location) of a tag device (such as tag device 120) having limited on-board power and computational resources (e.g., passive or semi-passive tags) by providing enhanced techniques for the TRP (such as TRP 340) to perform round-trip time (RTT) measurements. Specifically, the disclosed techniques facilitate the TRP's performance of RTT measurements even when performing positioning operations on tag devices such as tag device 120 that have limited on-board power, limited computational resources, operate asynchronously with the TRP, or a combination thereof. These RTT measurements can then be used to determine the location of the tag device.

[0100] Figure 4 is a ladder diagram that is an example of backscatter-based positioning according to aspects of the present disclosure. As Figure 4 shown,[[]] Figure 4The system 400 of ladder diagrams includes a tag device 120 and a TRP 405. The tag device 120 can correspond to a passive or semi-passive tag device. Additionally or alternatively, the tag device 120 can correspond to an active tag device operating in a reflection mode rather than an active transmission mode. The TRP 405 can correspond to a Tx / Rx TRP operating in a full-duplex mode.

[0101] At 402, the TRP 405 can send a configuration signal such as configuration signal 372 to the tag device 120. Subsequently, at 404, the TRP 405 can send a PRS such as PRS 374 to the tag device 120. Thereafter, at 406, the TRP can receive a backscatter signal 406 from the tag device 120.

[0102] In some embodiments and with reference to 404, the backscatter signal received at the TRP 405 can be dichotomous. The first part of the backscatter signal can include or correspond to the PRS reflected back to the TRP 405 by the tag device 120 without modulation but possibly with interference. The interference can include self-interference attributable to the TRP 405, interference from environmental sources (such as reflections from objects near the tag device 120), or a combination thereof, as explained at least herein with reference to Figure 6 Further explained.

[0103] The second part of the backscatter signal can include or correspond to the PRS modulated with modulation data, such as the PRS indicated to the tag device by a modulation scheme (e.g., modulation scheme 392) included in the configuration signal. In some embodiments, only the backscatter signal received at the TRP 405 can have a single part that includes or corresponds to the PRS modulated with modulation data. In any case, despite the asynchronous operation of the tag device and the TRP 405, the TRP 405 can still use the backscatter signal that includes the PRS modulated with modulation data to determine the RTT, as explained above and as referenced Figure 7 Further explained.

[0104] Figure 5 Is a conceptual diagram illustrating the timing supporting backscatter-based positioning according to one or more aspects. Initially, a TRP such as TRP 340 operates in a Tx mode 502 to send a configuration signal 372 (signal X) and a PRS 374 (signal Y). A timing gap 512 can separate the configuration signal 372 and the PRS 374. For example, the time period corresponding to the gap 512 can elapse from the first time of sending the configuration signal 372 and the second time of sending the PRS 374.

[0105] Note that the TRP can send a configuration signal X and a PRS Y. The configuration signal X can provide power-on (e.g., an energy portion), addressing, or both. The addressing of the configuration signal X can indicate specific tag devices that should wake up for backscatter transmission operations. The PRS Y can include a source signal carrying timing information. The timing information is configured to be backscattered by the tag device so that the TRP can compare the backscattered signal with the transmission timing. In some embodiments, the PRS Y can be a broadband sequence, such as a CDMA-type PN sequence with low autocorrelation.

[0106] A tag device operating in Rx mode 504, such as tag device 120, can receive a configuration signal 372 and a PRS 374. However, as Figure 5 depicted, the tag device can receive the configuration signal 372 and the PRS 374 with time delays 510, 514. Regarding the time delay 514, there is no requirement for the relative positions of the configuration signal X and the PRS Y, except that the PRS Y follows the configuration signal X. Although the time delay 514 is shown, in other embodiments, there may be no time delay 514. The time delay 514 can account for the processing delay at the tag device 120 to detect the addressing in the configuration signal X and turn on or configure the backscatter circuit of the tag device 120. During this processing delay, the tag device 120 will not perform backscattering and wastes the energy consumed by the tag device 120 for backscattering. In other words, the time delay 514 achieves power savings for the tag device 120, and the time delay 514 can be long enough for the PRS Y to start after the configuration signal X (and after the processing delay of the tag device 120).

[0107] The tag device can process the configuration signal and the PRS, and the time for processing the foregoing signals can correspond to the time delay 516. Additionally, in some embodiments, some PRS data may be lost due to the processing delay. After the end of the time delay 516, the tag device operating in Tx mode 506 can be configured to send a backscattered signal 376 (signal Y') including a PRS (Y) modulated with modulation data (Z). Due to the lost PRS data associated with the processing delay, the transmitted backscattered signal 376 may not include a portion of the reflected PRS. The TRP operating in Rx mode 508 can receive the backscattered signal 376 after the time delay 516.

[0108] In some embodiments, the PRS 374 may include one or more data portions and one or more energy portions. During one or more data portions, the tag device 120 may reflect the PRS 374 to generate a backscatter signal 376. The backscatter signal 376 may be modulated based on the configuration signal 372. During one or more energy portions, the tag device 120 may collect energy based on the PRS 374. For example, the tag device 120 may turn on backscattering during the data portion and may turn off backscattering during the energy portion. In some embodiments, the on / off pattern or sequence may be standardized. In some embodiments, a modulation scheme 392, such as a scrambling sequence, may be defined for the entire positioning session that includes the data and energy portions of the PRS 374, but during the energy portion, nothing is reflected back from the tag device 120.

[0109] Figure 6 is a conceptual diagram depicting interference at the TRP in one or more aspects. Specifically, the TRP operating in the Rx mode may experience self-interference 604, corresponding to h c c(t), as explained with reference to Figure 3 . The self-interference may occur at frequency 602. Additionally, the TRP may experience ambient interference 606, such as from an object in proximity to the tag device, such as a static or moving object. The ambient interference 606 may correspond to ∑ i h i c(t - t i ), as explained above with reference to Figure 3 . The backscatter signal 610 without interference may correspond to h b c(t - t c )b(t - t b ), as described with reference to Figure 3 . As shown, the backscatter signal 610 is frequency-shifted compared to the self-interference 604.

[0110] Figure 7 is a conceptual diagram illustrating the timing associated with backscatter-based positioning according to one or more aspects. Specifically, Figure 7 depicts the TRP, such as the TRP 340, in the Tx mode 702 and the Rx mode 704. In the Tx mode 702, the TRP may be configured to transmit the PRS 374. The PRS 374 may include a plurality of symbols Y(1)... Y(10). Each symbol may represent a fixed duration. For example, each of Y(1)... Y(10) may represent a 10 microsecond (μs) time frame; however, it should be understood that the symbol may be any fixed time frame.

[0111] The TRP operating in Rx mode 704 can receive the backscatter signal 376. In some embodiments, the backscatter signal 376 is bipartite, including a first part and a second part. The first part can be a reflection of the PRS 374 without manipulation of the tag device. For example, the first part can be the PRS 374 reflected by the tag device, and the tag device does not modulate the PRS 374 with the modulation data received via a configuration signal such as the configuration signal 372. However, the first part can include interference, such as that described in reference Figure 7 The second part can include the PRS 374 (e.g., symbols of the PRS) modulated with the modulation data (Z).

[0112] The TRP can be configured to use the first part (e.g., corresponding to the symbols Y(1)...Y(4) of the PRS 374) to evaluate self-interference, environmental interference, or a combination thereof. For example, the TRP can monitor the channel for the backscatter signal 376 (e.g., monitor the channel for the second part of the backscatter signal 376) after transmitting the PRS 374, and can use the first part to identify interference in the channel.

[0113] The TRP can be configured to use the second part to determine the RTT of the PRS 374 and the backscatter signal 376. By way of illustration, the TRP can maintain a record of the first time when the TRP initiates the transmission of the PRS 374 (e.g., in the memory 304). Since each symbol corresponds to a fixed time frame, the TRP can determine the second time when the TRP transmits the symbol Y(7) of the PRS 374. Additionally, the TRP can record the third time when the TRP receives the reflected backscatter signal 376 of the symbol Y(5)*Z(1). The TRP can be configured to compare the second time and the third time to determine the RTT of the PRS 374 and the backscatter signal 376. In other words, the tag device can start backscatter modulation from Y(5), and the TRP can detect the signal part II through the correlation with Y(5)*Z(1). The TRP can compare the current timing of Y(7) with the received Y(5) (demodulated from Y(5)*Z(1)) and determine that the RTT is two time units (e.g., the time frame of Y). Based on the RTT (and other RTT measurements performed by other TRPs), the location of the tag device can be determined by TOA, TDOA, AoA, or a combination thereof.

[0114] In some specific implementations, the backscatter signal 376 includes only a single part (e.g., the second part), where the PRS 374 is modulated with modulation data to generate the backscatter signal 376 (denoted by the symbol Y(5)*Z(1)...Y(10)*Z(6)). Instead of receiving the first part, the TRP may be configured to monitor the channel for the backscatter signal 376 (e.g., the PRS modulated with modulation data) after transmitting the PRS 374. By monitoring the channel, the TRP can identify interference in the channel.

[0115] Figure 8 is a conceptual diagram illustrating timing associated with backscatter-based positioning according to one or more aspects. The tag device 120 receives a configuration signal (X), followed by a PRS (Y). However, before the tag device 120 modulates the received PRS (Y) with modulation data (e.g., during backscatter operation), the tag device 120 processes the configuration signal (X). For example, the tag device 120 may process the configuration signal (X) by decoding an address included in the configuration signal to determine whether to continue processing the configuration signal. In response to determining that the configuration signal is addressed to the tag device 120, the tag device 120 may continue to process the configuration signal. For example, the tag device 120 may process a modulation scheme (e.g., modulation scheme 392) to derive modulation data, and the tag device 120 may modulate the modulation data with the PRS to generate a backscatter signal, such as the backscatter signal 376.

[0116] When the tag device 120 performs the foregoing processing of the configuration signal, the tag device 120 may receive a portion of the PRS. However, the tag device 120 may be configured to process the PRS only after processing the configuration signal, such that the tag device 120 can only use a portion of the PRS to generate a backscatter signal by modulating the modulation data with the PRS. The foregoing delay may be referred to as the tag processing delay period. Thus, in some specific implementations, the tag device processes the configuration signal during the tag processing delay period and then modulates the PRS with the modulation data after the tag processing delay period ends during the modulation time period.

[0117] In some specific implementations, the tag device 120 is configured to detect the configuration signal (X). The power-on portion (e.g., wake-up portion) of the configuration signal (X) may provide or enable detection of another portion of the configuration signal (X). Alternatively, if the tag device 120 includes its own power source, the power-on portion of the configuration signal (X) may not be used. Another portion of the configuration signal (X) may include addressing information such that the correct tag device 120 processes the PRS (Y).

[0118] In some specific implementations, after detecting the configuration signal (X), the tag device 120 will activate the backscatter transmission operation, but it is affected by processing delays. The backscatter transmission operation can be activated for a period of time. The overlapping part of the backscatter transmission operation and the incoming PRS (Y) can determine the usable part of the backscatter signal carrying information to determine the RTT. It should be noted that a certain degree of alignment between the PRS (Y) and the backscatter transmission operation can improve the transmission efficiency. There is no strict requirement for alignment, and some waste is acceptable for handling unknown factors (such as unknown processing delay times). Additionally, it should be noted that the techniques described herein may not require time synchronization (chip-level) between the backscatter transmission operation and the PRS (Y), resulting in a simple implementation at the tag device 120 (e.g., low-overhead signaling and power consumption).

[0119] Figure 9 is a conceptual diagram illustrating timing associated with backscatter-based positioning according to one or more aspects. Figure 9 Depicts the PRS (Y), the backscatter signal 904 (Y'), the first reflection 906, and the second reflection 908. In some specific implementations, the PRS 902 can be a periodic signal with a period T. Therefore, to resolve timing offsets (such as the tag processing delay period), the TRP can be configured to monitor the backscatter signal 904 during a time frame set by the period T of the PRS 902. For example, the TRP can monitor the backscatter signal 904 during a time frame equal to an integer multiple K of the period T. In such specific implementations, the TRP can ignore boundary effects (the start and end of the signal and backscatter); rather, the TRP can process a portion of the backscatter signal, such as the middle portion. It should be noted that the TRP may not use all samples of the backscatter signal, but the use of a monitoring window will reduce the processing overhead. Additionally, sample loss can be minimized by appropriately controlling the window position (e.g., relative to the transmission of the PRS (Y)).

[0120] Figure 10 is a conceptual diagram illustrating timing associated with backscatter-based positioning according to one or more aspects. As Figure 10 depicted, the TRP can be configured to generate a PRS (Y) with a specific period T. In some specific implementations, the period T can be selected to accommodate the reference Figure 8 tag processing delay period described. The TRP can be configured to monitor the backscatter signal (Y') within a time window that is an integer (K) multiple of the period T. One or more reflections based on the backscatter signal may also be present during the monitoring, such as the first reflection and the second reflection. Based on the different delays of the backscatter signal (Y'), the first reflection, and the second reflection, each of the backscatter signal (Y'), the first reflection, and the second reflection can have an offset (e.g., a time offset) relative to the PRS (Y).

[0121] The cyclic structure of PRS(Y) can help reduce the complexity associated with timing PRS(Y) and the received backscattered signal (Y'). For illustration, in some specific implementations, if PRS(Y) is periodic (with period T) and the detection window length is a multiple (K) of this period, then the RTT becomes a cyclic delay / shift. The cyclic shift detection can be performed as a phase ramp in the frequency domain. Note that the period T can be chosen to avoid any ambiguity, and T can be at least longer than the expected maximum RTT. In such specific implementations, the detection problem remains in the form h c c(t)+h b C(T - T c )B(T - t b ) + ∑ i H i C(T - t i ); however, the delay can be cyclic and t ∈ [0, KT].

[0122] Figure 11 is a flowchart illustrating an example process 1100 that supports backscatter-based positioning according to one or more aspects. The operations of process 1100 can be performed by a tag device, such as tag device 120 or the tag device described in reference Figure 4 For example, the example operations (also referred to as "boxes") of process 1100 can enable tag device 120 to support backscatter-based positioning.

[0123] At box 1102, the tag device receives a configuration signal that indicates the tag address of the tag device and the modulation scheme for generating the backscattered signal. For example, the configuration signal can include or correspond to configuration signal 372. The tag address can include or correspond to tag device information 309 or tag address 390. The modulation scheme can include or correspond to modulation scheme 392.

[0124] In some specific implementations, the configuration signal includes an energy signal. For example, the tag device can generate energy based on the energy signal. For illustration, the energy derived from the energy signal can be used to power one or more components of the tag device.

[0125] At box 1104, the tag device receives the PRS after receiving the configuration signal. For example, the PRS can include or correspond to PRS 374.

[0126] At block 1106, the tag device transmits a backscatter signal based on a modulation scheme and PRS. For example, the backscatter signal may include or correspond to backscatter signal 376. In some embodiments, the tag device modulates the PRS with modulation data based on the modulation scheme to generate the backscatter signal. In some embodiments, modulating the PRS with tag data occurs after the end of the tag processing delay period during the modulation time period. In some embodiments, the tag device transmits the backscatter signal after the end of the tag processing delay period.

[0127] In some embodiments, the tag device determines that a tag address included in a configuration signal indicates the tag device. In response to determining that the tag address indicates the tag device, the tag device may generate a backscatter signal based on the modulation scheme. In some embodiments, the tag device configures one or more components of the tag device based on the modulation scheme. For example, the one or more components may include or correspond to circuit 351, transmitter 356, or receiver 358. In some embodiments, the tag device processes the configuration signal during the tag processing delay period.

[0128] Figure 12 is a block diagram of an example tag device 1200 that supports backscatter-based positioning according to one or more aspects. The tag device 1200 may include or correspond to the tag device 120. For example, the tag device 1200 may include an RFID or IoT device. Additionally or alternatively, the tag device may include a passive device, a semi-passive device, or an active device.

[0129] The tag device 1200 may be configured to perform operations including the blocks of the process described with reference to Figure 11 In some embodiments, the tag device 1200 includes the structures, hardware, and components shown and described with reference to the tag device 120. For example, the tag device 1200 includes a controller 1280 that operates to execute logic or computer instructions stored in a memory 1282 and controls the components of the tag device 1200 that provide the features and functionality of the tag device 1200. The controller 1280 and the memory 1282 may include or correspond to circuit 351. The tag device 1200 transmits and receives signals via a wireless radio component 1201 and an antenna 1252 under the control of the controller 1280. In some embodiments, the wireless radio component 1201 and the antenna 1252 may include or correspond to the transmitter 356, the receiver 358, or a combination thereof. The wireless radio component 1201 includes various components and hardware. As an illustrative, non-limiting example, as described with reference to Figure 2 the tag device 1200 may include modulators and demodulators 254a-r, a MIMO detector 256, a receive processor 258, a transmit processor 264, and a TX MIMO processor 266.

[0130] The tag device 1200 further includes an energy harvesting circuit 1290. The energy harvesting circuit 1290 may include or correspond to circuit 351. The energy harvesting circuit 1290 may include hardware (e.g., circuitry), software, or a combination thereof configured to harvest energy from an energy source of the tag device 1200. For example, as an illustrative, non-limiting example, the energy source may include a solar energy source, a vibration energy source, or a thermal energy source. The energy harvesting circuit 1290 may be coupled to circuitry such as controller 1280, memory 1282, wireless radio components 1201, a power source of the tag device 1200, or a combination thereof. In some embodiments, the harvested energy may be used to charge a power source such as a battery or a capacitor. The power source may be coupled to controller 1280, memory 1282, wireless radio components 1201, or a combination thereof. Additionally or alternatively, the harvested energy may be configured to power one or more components of the tag device 1200.

[0131] As shown, the memory 1282 may include tag capability information 1202 and communication logic 1204. The tag capability information 202 may include or correspond to tag device information 309. The communication logic 1204 may be configured to enable communication between the tag device 1200 and one or more other devices. The tag device 1200 may receive signals from or send signals to one or more network entities (core network 130, LMF 131, reader device 121, TRP 340 or 405, UE 115, base station 105, or network entities as Figure 14 illustrated).

[0132] Note that the tag device 1200 may include fewer or more components than those described with reference to Figure 12 For example, in some embodiments, the tag device 1200 may include a power storage device. As another example, the tag device 1200 may not include the controller 1280.

[0133] Figure 13 is a flowchart illustrating an example process 1300 that supports backscatter-based positioning in accordance with one or more aspects. Operations of the process 1300 may be performed by a network entity (such as core network 130, LMF 131, reader device 121, TRP 340 or 405, UE 115, base station 105, or network entities as described with reference to Figure 14 For example, the example operations of the process 1300 may enable the TRP to support backscatter-based positioning.

[0134] At block 1302, the TRP transmits a configuration signal that indicates the tag address of the tag device and the modulation scheme for generating the backscatter signal. For example, the configuration signal may include or correspond to configuration signal 372. The tag address may include or correspond to tag device information 309 or tag address 390. The modulation scheme may include or correspond to modulation scheme 392. The tag device may include or correspond to tag device 120. In some specific implementations, the configuration signal includes an energy signal that is configured to be converted by the tag device into energy for energy harvesting.

[0135] In some specific implementations, the tag address indicates the tag identifier of the tag device, the group identifier associated with the tag device, or a combination thereof. The modulation scheme may indicate a frequency shift parameter, a phase scrambling parameter, an on / off mode, or a combination thereof. The on / off mode may indicate one or more transitions of the tag device from a first state to a second state or from the second state to the first state. The first state may correspond to the backscatter transmission state, and the second state may correspond to the energy harvesting state.

[0136] At block 1304, the TRP transmits a PRS after transmitting the configuration signal. For example, the PRS may include or correspond to PRS374. In some specific implementations, the PRS includes timing information, a broadband sequence, is periodic, or a combination thereof. For example, the broadband sequence may include a code division multiple access pseudo-random (CDMA-PN) sequence. Additionally or alternatively, the TRP may select the period of the PRS.

[0137] At block 1306, the TRP receives a backscatter signal from the tag device based on the modulation scheme and the PRS. For example, the backscatter signal may include or correspond to backscatter signal 376. In some specific implementations, the TRP correlates the backscatter signal with the PRS. The TRP may determine the RTT based on correlating the backscatter signal with the PRS.

[0138] In some specific implementations, the TRP is configured to operate in full-duplex mode. Additionally or alternatively, the TRP may be configured to operate asynchronously with the tag device.

[0139] In some specific implementations, the modulation scheme includes a frequency shift based on a frequency shift parameter, a phase scramble based on a phase scrambling parameter, modulation data, or a combination thereof. In some specific implementations, the TRP receives tag capability information corresponding to the tag device and determines a tag processing delay period based on the tag capabilities. In some specific implementations, the TRP transmitting the PRS after transmitting the configuration signal includes transmitting the PRS after the end of the tag processing delay period.

[0140] Figure 14is a block diagram of an example network entity 1400 that supports backscatter-based positioning according to one or more aspects. The network entity 1400 may include or correspond to the core network 130, the LMF 131, a reader device, the TRPs 340, 405, the UE 115, or the base station 105. The network entity 1400 may be configured to perform operations including referring to the blocks of the process 1300 described in Figure 13 In some specific implementations, the network entity 1400 includes the structure, hardware, and components shown and described for the base station 105 or the UE 115 with reference to Figure 1 or Figure 2 As an illustrative example, the network entity 1400 may include a controller 240 that operates to execute logic or computer instructions stored in a memory 242 and controls components that provide the features and functionality of the network entity 1400. The network entity 1400 transmits and receives signals under the control of the controller 240 via radio components 1401a-t and antennas 234a-t. The radio components 1401a-t include various components and hardware as illustrated for the base station 105 in Figure 2 including modulators and demodulators 232a-t, a transmit processor 220, a TX MIMO processor 230, a MIMO detector 236, and a receive processor 238.

[0141] As shown, the memory 242 may include configuration information 1402, tag device information 1403, RTT logic 1404, and communication logic 1405. The configuration information 1402 may include or correspond to information for generating a configuration signal 372 and may thus include a tag address 390, a modulation scheme 392, or a combination thereof. The tag device information 1403 may include or correspond to information 306, tag device information 309, or both. The RTT logic 1404 may be configured to determine the RTT based on a positioning reference signal (e.g., 374) and a backscatter signal (e.g., 376). The communication logic 1405 may be configured to enable communication between the network entity 1400 and one or more other devices. The network entity 1400 may receive signals from or send signals to one or more devices such as the tag device 120, the reader device 121, the core network 130, the LMF 131, the TRPs 340, 405, the UE 115, the base station 105, or another device.

[0142] Note that one or more of the blocks (or operations) described with reference to Figure 11 or Figure 13 may be combined with one or more of the blocks (or operations) described with reference to another figure in the various figures. For example, Figure 11 one or more of the blocks (or operations) of Figure 13One or more combinations of boxes (or operations). As another example, one or more boxes associated with Figure 13 can be combined with one or more operations described with reference to Figures 4 to 10 . As another example, one or more boxes associated with Figure 11 or Figure 13 can be combined with one or more boxes (or operations) associated with Figures 1 to 3 . Additionally or alternatively, one or more operations described above with reference to Figures 1 to 10 can be combined with one or more operations described with reference to Figure 12 or Figure 14 .

[0143] In one or more aspects, techniques for supporting backscatter-based positioning may include additional aspects, such as any single aspect or any combination of aspects described below or in combination with one or more other processes or devices described elsewhere herein. In a first aspect, techniques for supporting backscatter-based positioning may include transmitting a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The technique may also include transmitting a positioning reference signal (PRS) after transmitting the configuration signal. The technique further includes receiving a backscatter signal from the tag device based on the modulation scheme and the PRS. In some examples, the techniques in the first aspect may be implemented in a method or process. In some other examples, the techniques of the first aspect may be implemented in a communication device or a communication system. For example, a communication device may include a wireless communication device, such as a network entity, a core network, an LMF, a UE, a base station, a reader device, or components thereof. In some examples, a wireless communication device may include at least one processing unit or system (which may include an application processor, a modem, or other components) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium having program code stored thereon that, when executed by the processing unit, is configured to cause the wireless communication device to perform the operations described herein. Additionally or alternatively, the wireless communication device may include an interface (e.g., a wireless communication interface) that includes a transmitter, a receiver, or a combination thereof. Additionally or alternatively, the wireless communication device may include one or more components configured to perform the operations described herein.

[0144] In a second aspect, in combination with the first aspect, the configuration signal includes an energy signal that is configured to be converted by the tag device into energy for energy harvesting.

[0145] In a third aspect, in combination with the first or second aspect, the technique further includes the tag address indicating a tag identifier of the tag device, a group identifier associated with the tag device, or a combination thereof.

[0146] In a fourth aspect, in combination with one or more of the first to third aspects, the modulation scheme indicates a frequency shift parameter, a phase scrambling parameter, an on / off mode, or a combination thereof.

[0147] In a fifth aspect, in combination with the fourth aspect, the on / off mode indicates one or more transitions of the tag device from a first state to a second state or from the second state to the first state.

[0148] In a sixth aspect, in combination with the fifth aspect, the first state corresponds to a backscatter transmission state.

[0149] In a seventh aspect, in combination with the fifth or sixth aspect, the second state corresponds to an energy harvesting state.

[0150] In an eighth aspect, in combination with one or more of the first to seventh aspects, the PRS includes timing information, a broadband sequence, is periodic, or a combination thereof.

[0151] In a ninth aspect, in combination with the eighth aspect, the technique further includes selecting a period of the PRS.

[0152] In a tenth aspect, in combination with the ninth aspect, the bandwidth sequence includes a CDMA-PN sequence.

[0153] In an eleventh aspect, in combination with one or more of the first to tenth aspects, the technique further includes receiving tag capability information corresponding to the tag device.

[0154] In a twelfth aspect, in combination with the eleventh aspect, the technique further includes determining a tag processing delay period based on the tag capability.

[0155] In a thirteenth aspect, in combination with the twelfth aspect, in order to transmit the PRS after transmitting the configuration signal, the technique further includes transmitting the PRS after the end of the tag processing delay period.

[0156] In a fourteenth aspect, in combination with one or more of the first to thirteenth aspects, the technique further includes correlating the backscatter signal with the PRS.

[0157] In a fifteenth aspect, in combination with the fourteenth aspect, the technique further includes determining the RTT based on correlating the backscatter signal with the PRS.

[0158] In a sixteenth aspect, in combination with one or more of the first to sixteenth aspects, the modulation scheme includes a frequency shift based on the frequency shift parameter, a phase scramble based on the phase scrambling parameter, modulated data, or a combination thereof.

[0159] In a seventeenth aspect, in combination with one or more of the first to sixteenth aspects, the TRP is configured to operate in full-duplex mode.

[0160] In an eighteenth aspect, in combination with the seventeenth aspect, the TRP and the tag device are configured to operate asynchronously with respect to each other.

[0161] In a nineteenth aspect, in combination with one or more of the first to eighteenth aspects, the technique further includes monitoring a channel for backscatter signals after transmitting the PRS.

[0162] In a twentieth aspect, in combination with the nineteenth aspect, identifying interference in the channel, where the interference includes self-interference, environmental interference, or a combination thereof.

[0163] In a twenty-first aspect, in combination with the nineteenth or twentieth aspect, the technique further includes updating a modulation scheme based on the interference to cancel the interference.

[0164] In a twenty-second aspect, in combination with one or more of the first to twenty-first aspects, the technique further includes monitoring backscatter signals during a detection time window.

[0165] In a twenty-third aspect, in combination with the twenty-second aspect, the duration of the time window is greater than the period of the PRS.

[0166] In a twenty-fourth aspect, in combination with the twenty-second or twenty-third aspect, configuring the detection time window based on the period of the PRS.

[0167] In one or more aspects, techniques for supporting backscatter-based positioning may include additional aspects, such as any individual aspect or any combination of aspects described below or in combination with one or more other processes or devices described elsewhere herein. In a twenty-fifth aspect, techniques for supporting backscatter-based positioning may include receiving a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal. The technique may also include receiving a positioning reference signal (PRS) after receiving the configuration signal. The technique further includes transmitting a backscatter signal based on the modulation scheme and the PRS. In some examples, the techniques in the twenty-fifth aspect may be implemented in a method or process. In some other examples, the techniques of the twenty-fifth aspect may be implemented in a wireless communication device such as a tag device or an IoT device, which may include a passive tag, a semi-passive tag, an active tag, a UE, an RFID, or components thereof. In some examples, by way of illustrative, non-limiting example, the wireless communication device may include circuitry such as at least one processing unit or system (which may include an application processor, a modem, or other components) and at least one memory device coupled to the processing unit. The processing unit may be configured to perform the operations described herein with respect to the wireless communication device. In some examples, the memory device includes a non-transitory computer-readable medium having program code stored thereon that, when executed by the processing unit, is configured to cause the wireless communication device to perform the operations described herein. Additionally or alternatively, the wireless communication device may include an interface (e.g., a wireless communication interface) that includes a transmitter, a receiver, or a combination thereof. Additionally or alternatively, the wireless communication device may include one or more components configured to perform the operations described herein.

[0168] In a twenty-sixth aspect, in combination with the twenty-fifth aspect, the configuration signal includes an energy signal.

[0169] In a twenty-seventh aspect, in combination with the twenty-sixth aspect, the technique further includes generating energy based on the energy signal.

[0170] In a twenty-eighth aspect, in combination with the twenty-seventh aspect, the energy can be used to power one or more components of the tag device.

[0171] In a twenty-ninth aspect, in combination with one or more of the twenty-fifth through twenty-eighth aspects, the technique further includes determining that the tag address included in the configuration signal indicates the tag device.

[0172] In a thirtieth aspect, in combination with one or more of the twenty-fifth through twenty-ninth aspects, the technique further includes generating a backscatter signal based on the modulation scheme in response to determining that the tag address indicates the tag device.

[0173] In a thirty - first aspect, in combination with one or more of the twenty - fifth to thirtieth aspects, the technology further includes configuring one or more components of the tag device based on a modulation scheme.

[0174] In a thirty - second aspect, in combination with the thirty - first aspect, configuring one or more components occurs during a tag processing delay period.

[0175] In a thirty - third aspect, in combination with the thirty - second aspect, transmitting the backscatter signal occurs after the end of the tag processing delay period.

[0176] In a thirty - fourth aspect, in combination with one or more of the twenty - fifth to thirty - third aspects, the technology further includes modulating the PRS with modulation data based on a modulation scheme to generate a backscatter signal.

[0177] In a thirty - fifth aspect, in combination with one or more of the twenty - fifth to thirty - fourth aspects, the technology further includes processing a configuration signal during a tag processing delay period.

[0178] In a thirty - sixth aspect, in combination with the thirty - fifth aspect, modulating the PRS with modulation data occurs after the end of the tag processing delay period during a modulation time period.

[0179] Those skilled in the art should understand that any of a variety of different techniques and arts can be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may have been mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0180] As used herein Figures 1 to 14 The components, functional blocks, and modules described herein include processors, electronic devices, hardware devices, electronic components, logic circuits, memories, software code, firmware code, etc., or any combination thereof. Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, execution threads, procedures, and / or functions, etc., regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description language, or other terms. Additionally, the features discussed herein can be implemented via dedicated processor circuitry, via executable instructions, or a combination thereof.

[0181] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithmic steps described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such specific implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Those skilled in the art will also readily recognize that the order or combination of the components, methods, or interactions described herein are merely examples, and the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

[0182] The various illustrative logical components, logical blocks, modules, circuits, and algorithmic processes described in connection with the specific implementations disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0183] The hardware and data processing apparatus for implementing or performing the various illustrative logical components, logical blocks, modules, and circuits described in connection with the aspects disclosed herein can be realized using a general-purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. In some particular implementations, the processor may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some particular implementations, specific processes and methods may be performed by circuitry specific to a given function.

[0184] In one or more aspects, the described functionality may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and structural equivalents thereof, or any combination thereof. The specific implementations of the subject matter described in this specification may also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium for execution by, or to control the operation of, a data processing apparatus.

[0185] If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. The processes of the methods or algorithms disclosed herein may be implemented in a processor-executable software module that may reside on a computer-readable medium. A computer-readable medium includes both a computer storage medium and a communication medium including any medium that can be configured to transfer a computer program from one place to another. The storage medium may be any available medium accessible by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer. Additionally, any connection may be properly termed a computer-readable medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, operations of a method or algorithm may reside as one or any combination of code and instruction sets on a machine-readable medium and a computer-readable medium, which may be incorporated into a computer program product.

[0186] Various modifications to the specific embodiments described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to some other specific embodiments without departing from the spirit or scope of this disclosure. Therefore, the claims are not intended to be limited to the specific embodiments shown herein, but rather to cover the broadest scope consistent with this disclosure, the principles disclosed herein, and novel features.

[0187] Additionally, those of ordinary skill in the art will readily recognize that the terms “upper” and “lower” are sometimes used for ease of description of the figures and indicate relative positions corresponding to the orientation of the figures on a properly oriented page and may not reflect the correct orientation of any device as implemented.

[0188] Certain features that are described in the context of separate embodiments in this specification can also be implemented in combination in a single embodiment. Conversely, the various features that are described in the context of a single embodiment can also be implemented separately or in any suitable sub-combination in multiple embodiments. Additionally, although features may have been described above as acting in certain combinations and even initially claimed as such, one or more features from the claimed combination can in some cases be removed from the combination, and the claimed combination can be directed to a sub-combination or variations of the sub-combination.

[0189] Similarly, although operations are depicted in the figures in a particular order, this should not be construed as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed to achieve the desired result. Additionally, the figures may schematically depict one or more example processes in the form of flowcharts. However, other operations not depicted can be incorporated into the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, concurrently with, or between any of the illustrated operations. In certain environments, multitasking and parallel processing are advantageous. Moreover, the separation of the various system components in the embodiments described above should not be construed as requiring such separation in all embodiments, and it should be understood that the program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, some other embodiments also fall within the scope of the appended claims. In some cases, the acts recited in the claims can be performed in a different order and still achieve the desired result.

[0190] As used herein (including in the claims), the term "or" as used in a list of two or more items means that any of the listed items can be employed individually, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, or C, the composition can contain A alone; B alone; C alone; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Additionally, as used herein (including in the claims), "or" as used in a list of items that begins with "at least one of" indicates a disjunctive list, such that a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) or any combination of any of these items. The term "substantially" is defined as being largely but not necessarily completely what is specified (and includes what is specified; e.g., substantially 90 degrees includes 90 degrees, and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any disclosed embodiment, the term "substantially" can be replaced with "[percentage] within" what is specified, where the percentage includes 0.1%, 1%, 5%, or 10%.

[0191] The foregoing description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of wireless communication performed by a network entity, the method comprising: Sending a configuration signal, the configuration signal indicating a tag address of a tag device and a modulation scheme for generating a backscatter signal; Sending a positioning reference signal (PRS) after sending the configuration signal; And Receiving a backscatter signal from the tag device based on the modulation scheme and the PRS.

2. The method according to claim 1, wherein: The configuration signal includes an energy signal, the energy signal being configured to be converted by the tag device into energy for energy harvesting; or The tag address indicates a tag identifier of the tag device, a group identifier associated with the tag device, or a combination thereof.

3. The method according to claim 1, wherein: The modulation scheme indicates a frequency shift parameter, a phase scrambling parameter, an on / off mode, or a combination thereof; The on / off mode indicates one or more transitions of the tag device from a first state to a second state or from the second state to the first state, The first state corresponds to a backscatter transmission state, and The second state corresponds to an energy harvesting state.

4. The method according to claim 1, the method further comprising: Selecting a period of the PRS, and Wherein: The PRS includes timing information, a broadband sequence, is periodic, or a combination thereof; and The broadband sequence includes a code division multiple access pseudo-random (CDMA-PN) sequence.

5. The method according to claim 1, the method further comprising: Receiving tag capability information corresponding to the tag device; And Determining a tag processing delay period based on the tag capability, and Wherein sending the PRS after sending the configuration signal includes sending the PRS after the end of the tag processing delay period.

6. The method according to claim 1, the method further comprising: Correlating the backscatter signal with the PRS; Determining a round-trip time (RTT) based on correlating the backscatter signal with the PRS.

7. The method according to claim 1, wherein the modulation scheme includes: A frequency offset based on a frequency offset parameter, A phase scramble based on a phase scramble parameter, Modulating data, or A combination thereof.

8. The method according to claim 1, wherein: The network entity is configured to operate in a full-duplex mode, and The network entity and the tag device are configured to operate asynchronously with each other.

9. The method according to claim 1, the method further comprising: Monitoring a channel for the backscatter signal after sending the PRS, the channel being monitored according to a monitoring window having a duration less than the duration of the PRS; Identifying interference in the channel, wherein the interference includes self-interference, environmental interference, or a combination thereof; and Updating the modulation scheme based on the interference to cancel the interference.

10. The method according to claim 1, the method further comprising: Monitoring the backscatter signal during a detection time window, and Wherein the duration of the time window is greater than the period of the PRS, and The detection time window is configured based on the period of the PRS.

11. A network entity, the network entity comprising: at least one processor; and a memory coupled to the at least one processor, the at least one processor being configured to: send a configuration signal that indicates a tag address of a tag device and a modulation scheme for generating a backscatter signal; send a positioning reference signal (PRS) after sending the configuration signal; and receive a backscatter signal from the tag device based on the modulation scheme and the PRS.

12. The network entity according to claim 11, wherein: the configuration signal includes an energy signal configured to be converted by the tag device into energy for energy harvesting; or the tag address indicates a tag identifier of the tag device, a group identifier associated with the tag device, or a combination thereof.

13. The network entity according to claim 11, wherein: the modulation scheme indicates a frequency shift parameter, a phase scrambling parameter, an on / off mode, or a combination thereof; the on / off mode indicates one or more transitions of the tag device from a first state to a second state or from the second state to the first state, the first state corresponds to a backscatter transmission state, and the second state corresponds to an energy harvesting state.

14. The network entity according to claim 11, wherein the at least one processor is further configured to: select a period of the PRS, and wherein: the PRS includes timing information, a broadband sequence, is periodic, or a combination thereof; and the broadband sequence includes a code division multiple access pseudo-random (CDMA-PN) sequence.

15. The network entity according to claim 11, wherein the at least one processor is further configured to: receive tag capability information corresponding to the tag device; and determine a tag processing delay period based on the tag capability, and wherein sending the PRS after sending the configuration signal includes sending the PRS after the end of the tag processing delay period.

16. The network entity according to claim 11, wherein the at least one processor is further configured to: correlate the backscatter signal with the PRS; determine a round-trip time (RTT) based on correlating the backscatter signal with the PRS.

17. The network entity according to claim 11, wherein the modulation scheme includes: a frequency offset based on a frequency offset parameter, a phase scramble based on a phase scramble parameter, modulated data, or a combination thereof.

18. The network entity according to claim 11, wherein: the network entity is configured to operate in a full-duplex mode, and the network entity and the tag device are configured to operate asynchronously with each other.

19. The network entity according to claim 11, wherein the at least one processor is further configured to: monitor a channel for the backscatter signal after sending the PRS; identify interference in the channel, where the interference includes self-interference, environmental interference, or a combination thereof; and Update the modulation scheme based on the interference to cancel the interference.

20. The network entity according to claim 11, wherein the at least one processor is further configured to: Monitor the backscattered signal during a detection time window, and wherein the duration of the time window is greater than the period of the PRS, and wherein the detection time window is configured based on the period of the PRS.

21. A method for wireless communication performed by a tag device, the method comprising: Receiving a configuration signal that indicates a tag address of the tag device and a modulation scheme for generating a backscattered signal; Receiving a positioning reference signal (PRS) after receiving the configuration signal; And Transmitting a backscattered signal based on the modulation scheme and the PRS.

22. The method according to claim 21, wherein: The configuration signal includes an energy signal; and The energy generated based on the energy signal can be used to power one or more components of the tag device.

23. The method according to claim 21, the method further comprising: Determining that the tag address included in the configuration signal indicates the tag device; And Generating the backscattered signal based on the modulation scheme in response to determining that the tag address indicates the tag device.

24. The method according to claim 21, the method further comprising: Configuring one or more components of the tag device based on the modulation scheme, and wherein configuring the one or more components occurs during a tag processing delay period, and wherein transmitting the backscattered signal occurs after the end of the tag processing delay period.

25. The method according to claim 21, the method further comprising: Modulating the PRS with modulation data based on the modulation scheme to generate the backscattered signal; And Processing the configuration signal during a tag processing delay period, and wherein modulating the PRS with the modulation data occurs after the end of the tag processing delay period during a modulation time period.

26. A tag device, the tag device comprising: At least one processor; And A memory coupled to the at least one processor, the at least one processor being configured to: Receive a configuration signal that indicates a tag address of the tag device and a modulation scheme for generating a backscattered signal; Receive a positioning reference signal (PRS) after receiving the configuration signal; And Transmit a backscattered signal based on the modulation scheme and the PRS.

27. The tag device according to claim 26, wherein: The configuration signal includes an energy signal; and The energy generated based on the energy signal can be used to power one or more components of the tag device.

28. The tag device according to claim 26, wherein the at least one processor is further configured to: Determine that the tag address included in the configuration signal indicates the tag device; and Generate the backscattered signal based on the modulation scheme in response to determining that the tag address indicates the tag device.

29. The tag device according to claim 26, wherein the at least one processor is further configured to: configure one or more components of the tag device based on the modulation scheme, and wherein the one or more components are configured during a tag processing delay period, and wherein the backscattered signal is transmitted after the end of the tag processing delay period.

30. The tag device according to claim 26, wherein the at least one processor is further configured to: modulate the PRS with modulation data based on the modulation scheme to generate the backscattered signal; and process the configuration signal during a tag processing delay period, and wherein the PRS is modulated with the modulation data after the end of the tag processing delay period during a modulation time period.

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