Sampled level orthogonal frequency division multiplexing (OFDM) backscatter for passive devices

Abstract

Systems, apparatus, processes, and computer readable media for wireless communication are disclosed. For example, a passive network device can receive an orthogonal frequency division multiplexing (OFDM) signal from a network device. The passive network device can transmit a backscatter signal based on the OFDM signal, the backscatter signal including frequencies of the OFDM signal shifted to non-overlapping frequencies.

Description

Technical Field

[0001] All aspects of this disclosure relate to wireless communication. For example, aspects of this disclosure relate to sample-level orthogonal frequency division multiplexing (OFDM) backscattering for passive devices, such as Ambient Internet of Things (AIoT) devices. Background Technology

[0002] Wireless communication systems are deployed to provide a variety of telecommunications services, including telephone, video, data, messaging, and broadcasting. Wireless communication systems have undergone several generations of development, including first-generation analog wireless telephone service (1G), second-generation (2G) digital wireless telephone service (including the transitional 2.5G networks), third-generation (3G) high-speed data wireless service with internet capabilities, fourth-generation (4G) services (e.g., LTE, WiMax), and fifth-generation (5G) services (e.g., New Radio (NR)). Currently, many different types of wireless communication systems are in use, including cellular systems and Personal Communication Services (PCS) systems. Known examples of cellular systems include cellular analog Advanced Mobile Phone Systems (AMPS), and digital cellular systems based on Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), etc. Summary of the Invention

[0003] The following is a simplified summary of the invention relating to one or more aspects disclosed herein. Therefore, this summary should not be considered an exhaustive overview relating to all conceived aspects, nor should it be considered to identify key or decisive elements relating to all conceived aspects or to depict the scope associated with any particular aspect. Thus, the sole purpose of this summary is to present, in a concise form, certain concepts relating to one or more aspects involving the mechanisms disclosed herein, prior to the detailed description presented below.

[0004] Systems and techniques for wireless communication are described. According to at least one exemplary example, a passive network device for wireless communication is provided. The passive network device includes at least one memory and at least one processor coupled to the at least one memory and configured to: receive an orthogonal frequency division multiplexing (OFDM) signal from the network device; and induce the transmission of a backscattered signal based on the OFDM signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

[0005] In another exemplary example, a method for wireless communication performed at a passive network device is provided. The method includes: receiving an orthogonal frequency division multiplexing (OFDM) signal from a network device by the passive network device; and transmitting a backscattered signal by the passive network device based on the OFDM signal, the backscattered signal including frequencies of the OFDM signal shifted to non-overlapping frequencies.

[0006] In another exemplary example, a non-transitory computer-readable storage medium is provided having instructions stored thereon that, when executed by at least one processor, cause the at least one processor to: receive an orthogonal frequency division multiplexing (OFDM) signal from a network device; and, based on the OFDM signal, induce the transmission of a backscattered signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

[0007] In another exemplary example, an apparatus for wireless communication is provided, the apparatus comprising: means for receiving an orthogonal frequency division multiplexing (OFDM) signal from a network device; and means for transmitting a backscattered signal based on the OFDM signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

[0008] The aspects generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices and / or processing systems, as fully described herein with reference to the accompanying drawings and description, and as illustrated in the accompanying drawings and description.

[0009] The features and technical advantages of the examples according to this disclosure have been summarized rather extensively above in order to better understand the detailed description below. Additional features and advantages will be described below. The disclosed concepts and specific examples can be readily used as the basis for modifying or designing other structures for achieving the same purpose as this disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, in both their organization and manner of operation, and the associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the drawings provided is for illustrative and descriptive purposes and not as a definition of limitation of the claims.

[0010] While aspects are described herein by way of example, those skilled in the art will understand that such aspects can be implemented in many different arrangements and scenarios. The techniques described herein can be implemented using different platform types, devices, systems, shapes, sizes, and / or package arrangements. For example, some aspects can be implemented via integrated chip implementations or other devices based on non-modular components (e.g., end-user equipment, vehicles, communication equipment, computing devices, industrial equipment, retail / shopping devices, medical devices, and / or artificial intelligence devices). Aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, and / or system-level components. Devices incorporating the described aspects and features may include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals may include one or more components for analog and digital purposes (e.g., hardware components including antennas, radio frequency (RF) chains, power amplifiers, modulators, buffers, processors, interleavers, adders, and / or summers). The aspects described herein are intended to be practiced in a wide variety of devices, components, systems, distributed arrangements, and / or end-user equipment of various sizes, shapes, and configurations.

[0011] Based on the accompanying drawings and detailed description, other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to define the scope of the claimed subject matter. This subject matter should be understood with reference to the appropriate portions of the entire specification, any or all of the drawings, and each claim.

[0012] The foregoing and other features and aspects will become more apparent from the following description, claims and accompanying drawings. Attached Figure Description

[0013] The accompanying drawings are provided to help describe various aspects of this disclosure, and are provided for illustrative purposes only and not to limit the aspects.

[0014] Figure 1 This is a block diagram illustrating an example of a wireless communication network based on some examples; Figure 2 These are illustrations of base station and user equipment (UE) designs based on some examples, which enable the transmission and processing of signals exchanged between the UE and the base station; Figure 3 This is a diagram illustrating an example of a decomposed base station based on some examples; Figure 4 This is a block diagram illustrating the components of a user equipment (UE) based on some examples; Figure 5This is a diagram illustrating examples of passive devices based on some examples; Figure 6 This is a diagram illustrating a sample single-site deployment scenario for passive devices, based on some examples; Figure 7 This is a diagram illustrating an example dual-site deployment scenario for passive devices, based on some examples; Figure 8 This is a diagram illustrating examples of systems for performing backscatter communication, based on some examples; Figure 9 This is a diagram illustrating an example of symbol-level OFDM backscattering based on some examples; Figure 10 This is a diagram illustrating examples of forming backscattered signals based on OFDM signals, according to some examples; Figure 11 This is an illustration of an example of a bi-station deployment scenario with backscattered signals based on a single-tone OFDM signal, according to some examples; Figure 12 This is a diagram illustrating an example of a first configuration of a backscattered signal for symbol-level OFDM backscattering, based on some examples; Figure 13 This is a diagram illustrating an example of a second configuration of the backscattered signal for symbol-level OFDM backscattering, based on some examples; Figure 14 This is a diagram illustrating an example of the mode of a demodulation reference signal (DMRS) subcarrier for an OFDM signal, based on some examples. Figure 15 This is a diagram illustrating an example of an OFDM signal divided into multiple segments, based on some examples; Figure 16 This is a diagram illustrating an example of the configuration of a backscattered signal for symbol-level OFDM backscattering, based on some examples. Figure 17 This is a flowchart illustrating an example of a wireless communication process performed at a network device, based on some examples; and Figure 18 This is a block diagram illustrating an example of a computing system based on some examples. Detailed Implementation

[0015] Certain aspects of this disclosure are provided below for illustrative purposes. Alternative aspects may be devised without departing from the scope of this disclosure. Furthermore, well-known elements of this disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of this disclosure. Some of the aspects described herein can be applied independently, and some of them can be combined, as will be apparent to those skilled in the art. In the following description, specific details are set forth for illustrative purposes to provide a thorough understanding of various aspects of this application. However, it will be apparent that various aspects can be practiced without these specific details. The accompanying drawings and descriptions are not intended to be limiting.

[0016] The following description provides only exemplary aspects and is not intended to limit the scope, applicability, or configuration of this disclosure. Rather, the following description of the exemplary aspects will provide those skilled in the art with a description that can be used to implement the exemplary aspects. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope of this application as set forth in the appended claims.

[0017] Wireless communication networks can be deployed to provide a variety of communication services, such as voice, video, packet data, message sending and receiving, broadcasting, any combination thereof, or other communication services. Wireless communication networks can support both access links and sidelinks for communication between wireless devices. An access link can refer to any communication link between a client device (e.g., a User Equipment (UE), Station (STA), or other client device) and a base station (e.g., a 3GPP gNB for 5G / NR, a 3GPP eNB for 4G / LTE, a Wi-Fi access point (AP), or other base station). For example, an access link can support uplink signaling, downlink signaling, connection procedures, etc. An example of an access link is the Uu link or interface (also known as NR-Uu) between a 3GPP gNB and a UE.

[0018] In various wireless communication networks, a wide range of client devices can be utilized that can be associated with different signaling and communication needs. For example, as 5G networks expand into industrial verticals and the number of deployed Internet of Things (IoT) devices grows, network service categories such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC) can be expanded to better support a variety of IoT devices, including passive IoT devices, semi-passive IoT devices, and so on.

[0019] For example, environmental IoT devices (such as passive and semi-passive IoT devices) are relatively low-cost UEs that can be used to implement one or more sensing and communication capabilities in an IoT network or deployment. In some examples, passive and / or semi-passive IoT sensors (e.g., devices) can be used to provide sensing capabilities for a variety of processes and use cases, such as asset management, logistics, warehousing, manufacturing, etc. Passive and semi-passive IoT devices may include one or more sensors, processors or microcontrollers, and energy harvesters for generating electricity from incident downlink radio frequency (RF) signals received from the passive or semi-passive IoT device.

[0020] In wireless communication network environments (e.g., cellular networks), network devices (e.g., base stations, gNBs, or UEs) can be used to transmit downlink RF signals to passive devices (e.g., AIoT devices, such as energy harvesting devices). In an exemplary example, a base station or gNB can read and / or write information stored on an energy harvesting IoT device by transmitting downlink RF signals. The downlink RF signals can provide power to the energy harvesting IoT device and can be used as the basis for uplink signals carrying information transmitted back to the network device by the energy harvesting IoT device (e.g., based on a portion of the downlink RF signal incident by reflection or backscattering). The base station or gNB can read reflected signals transmitted by the energy harvesting IoT device to decode information transmitted by the IoT device (e.g., sensor information collected by one or more sensors included in the IoT device).

[0021] Recently, AIoT (e.g., passive IoT) technology has attracted much attention in the industry (e.g., within 3GPP). Currently, research is underway on 3GPP Release 19 SA 1 SID for IoT devices enabling ambient power, and a 3GPP RAN plenary study entitled "New SID: Study on Ambient IoT" has been approved in RP-222685.

[0022] AIoT devices (e.g., passive devices) are ultra-low complexity and ultra-low power devices that offer several orders of magnitude lower complexity and power consumption than existing active IoT devices. Type A devices (e.g., passive devices such as AIoT devices) are battery-free devices with no energy storage capacity and rely entirely on the availability of an external energy source (e.g., for RF energy harvesting). Type B devices (e.g., semi-passive IoT devices) have limited energy storage (e.g., supercapacity or conventional capacity energy storage) that does not require manual replacement or recharging.

[0023] AIoT devices (e.g., tags, backscatter UEs (BUEs), or passive UEs (PUEs)) are typically passive devices without active RF components. For example, a PUE may perform data transmission based on modulating incident RF signals emitted by an ambient transmitter (e.g., a base station or UE). The ambient RF signal can be used not only as a signal resource for backscattering but also as an energy resource for energy harvesting by the device.

[0024] RFID tags are an existing battery-free technology. However, RFID tags have a limited read range of only a few meters, making it difficult to support large-scale deployments of RFID tags with seamless coverage. Therefore, new designs for IoT devices that enable environmental power in NR may be beneficial.

[0025] This document describes systems, apparatus, processes (also referred to as methods), and computer-readable media (collectively, the “System and Technology”) for providing sample-level OFDM backscattering for AIoT devices, such as passive devices like RFID tags. In one or more aspects, the System and Technology relates to modifying backscattering techniques to enable the reuse of OFDM waveforms and receivers. In one or more examples, the System and Technology employ sample-level OFDM backscattering to increase the data rate of IoT devices in an environment. However, in some cases, sample-level OFDM backscattering can lead to channel estimation errors on the reader side. The System and Technology provides solutions to minimize these potential errors.

[0026] In one or more examples, the backscatter packet may include a continuous square wave with a time-varying frequency, a preamble, and a payload. The continuous square wave may be associated with one or more OFDM DMRS symbols and can be used for channel estimation on the reader side. The preamble can be used by the reader to locate the start of the backscatter sample relative to the OFDM symbol boundary in the OFDM signal.

[0027] In some examples, backscatter packets may include a preamble and a payload. The DMRS tone (subcarrier) of an OFDM signal can be divided into multiple segments, with zero-power subcarriers located between these segments. The reader can estimate both the channel and timing offset based on the shifted DMRS tone.

[0028] Other aspects of the system and technology will be described in relation to the accompanying drawings.

[0029] As used in this article, the phrase “based on” should not be interpreted as referring to a closed set of information, one or more conditions, one or more factors, etc. In other words, the phrase “based on A” (where “A” can be information, conditions, factors, etc.) should be interpreted as “based on at least A”, unless otherwise stated otherwise.

[0030] As used herein, the terms “User Equipment” (UE) and “Network Entity” are not intended to be specific to or otherwise limited to any particular Radio Access Technology (RAT), unless otherwise specified. In general, a UE can be any wireless communication device (e.g., mobile phone, router, tablet computer, laptop computer, and / or tracking device, etc.), wearable device (e.g., smartwatch, smart glasses, wearable ring, and / or extended reality (XR) device (such as virtual reality (VR) headsets, augmented reality (AR) headsets or glasses, or mixed reality (MR) headsets)), vehicle (e.g., car, motorcycle, bicycle, etc.), aircraft (e.g., airplane, jet, unmanned aerial vehicle (UAV) or drone, helicopter, airship, glider, etc.), and / or Internet of Things (IoT) device, etc., for a user to use to communicate over a wireless communication network. A UE can be mobile or can (e.g., at certain times) be stationary and can communicate with a Radio Access Network (RAN). As used herein, the term "UE" can be interchangeably referred to as "access terminal" or "AT," "client device," "wireless device," "subscriber device," "subscriber terminal," "subscriber station," "user terminal," or "UT," "mobile device," "mobile terminal," "mobile station," or variations thereof. In general, a UE can communicate with the core network via the RAN, and through the core network, the UE can connect to external networks such as the Internet and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through wired access networks, wireless local area network (WLAN) networks (e.g., based on the IEEE 802.11 communication standard), etc.

[0031] Network entities can be implemented in a converged or monolithic base station architecture, or alternatively, in a decomposed base station architecture, and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC. A base station (e.g., with a converged / monolithic or decomposed base station architecture) may operate according to one of several RATs communicating with the UE (depending on the network in which it is deployed), and may alternatively be referred to as an access point (AP), network node, NodeB (NB), evolved NodeB (eNB), next-generation eNB (ng-eNB), new radio (NR) NodeB (also known as gNB or gNodeB), etc. The base station may primarily be used to support the UE's radio access, including supporting data, voice, and / or signaling connections for the supported UE. In some systems, the base station may provide edge node signaling functions, while in others, it may provide additional control and / or network management functions. The communication links through which a UE can transmit signals to a base station are called uplink (UL) channels (e.g., reverse traffic channels, reverse control channels, access channels, etc.). The communication links through which a base station can transmit signals to a UE are called downlink (DL) or forward link channels (e.g., paging channels, control channels, broadcast channels, or forward traffic channels, etc.). As used herein, the term traffic channel (TCH) can refer to uplink, reverse or downlink, and / or forward traffic channel.

[0032] The terms "network entity" or "base station" (e.g., having a converged / monolithic or decomposed base station architecture) can refer to a single physical transmit / receive point (TRP) or multiple physical TRPs that may be co-located or non-co-located. For example, when the term "network entity" or "base station" refers to a single physical TRP, that physical TRP may be a base station antenna corresponding to a cell (or several cell sectors) of the base station. When the term "network entity" or "base station" refers to multiple co-located physical TRPs, these physical TRPs may be antenna arrays of the base station (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming). When the term "base station" refers to multiple non-co-located physical TRPs, the physical TRPs may be a distributed antenna system (DAS) (e.g., a network of spatially separated antennas connected via a transmission medium to a common source) or a remote radio headend (RRH) (e.g., a remote base station connected to a serving base station). Alternatively, a non-co-located physical TRP can be the serving base station from which the UE receives measurement reports and the neighboring base station where the UE is measuring its reference radio frequency (RF) signal (e.g., or simply "reference signal"). Because, as used herein, a TRP is the point by which a base station transmits and receives radio signals, references to transmitting from or receiving at a base station should be understood to refer to the specific TRP of that base station.

[0033] In some specific implementations supporting UE positioning, network entities or base stations may not support the UE's radio access (e.g., may not support data, voice, and / or signaling connections regarding the UE), but instead may transmit reference signals to the UE for measurement, and / or receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., in the case of transmitting signals to the UE) and / or as a location measurement unit (e.g., in the case of receiving and measuring signals from the UE).

[0034] As described herein, a node (which may be referred to as a node, network node, network entity, or wireless node) may include, may be included in, or may be a component of: a base station (e.g., any base station described herein), a UE (e.g., any UE described herein), a network controller, apparatus, device, computing system, integrated access and backhaul (IAB) node, distributed unit (DU), central unit (CU), remote / radio unit (RU) (which may also be referred to as a remote radio unit (RRU)), and / or another processing entity configured to perform any of the techniques described herein. For example, a network node may be a UE. As another example, a network node may be a base station or a network entity. As yet another example, a first network node may be configured to communicate with a second or third network node. In one aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a UE. In another aspect of this example, the first network node may be a UE, the second network node may be a base station, and the third network node may be a base station. In still other aspects of this example, the first network node, the second network node, and the third network node may be different from these examples. Similarly, references to UE, base station, device, equipment, computing system, etc., may include disclosures of UE, base station, device, equipment, computing system, etc., as network nodes. For example, a disclosure of a UE being configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node. Consistent with this disclosure, once a particular example is extended according to this disclosure (e.g., a disclosure of a UE being configured to receive information from a base station also discloses that a first network node is configured to receive information from a second network node), a broader example of a narrower example may be interpreted in reverse, but in a broad, open-ended manner. In the above example where a UE is configured to receive information from a base station and a first network node is configured to receive information from a second network node, the first network node may refer to a first UE, a first base station, a first device, a first equipment, a first computing system, a first set of one or more components, or a first processing entity, etc., configured to receive information; and the second network node may refer to a second UE, a second base station, a second device, a second equipment, a second computing system, a second set of one or more components, or a second processing entity, etc.

[0035] As described herein, different terms may be used in various contexts to describe the transmission of information (e.g., any information, signal, etc.). Disclosure of one communication term includes disclosure of other communication terms. For example, a first network node may be described as being configured to send information to a second network node. In this example and consistent with this disclosure, disclosure that a first network node is configured to send information to a second network node includes disclosure that the first network node is configured to provide, transmit, output, communicate, or send information to the second network node. Similarly, in this example and consistent with this disclosure, disclosure that a first network node is configured to send information to a second network node includes disclosure that the second network node is configured to receive, obtain, or decode information provided, transmitted, output, communicate, or sent by the first network node.

[0036] RF signals comprise electromagnetic waves of a given frequency that transmit information across the space between a transmitter and a receiver. As used herein, a transmitter may send a single “RF signal” or multiple “RF signals” to a receiver. However, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple “RF signals” corresponding to each transmitted RF signal. The same transmitted RF signal on different paths between the transmitter and receiver can be referred to as a “multipath” RF signal. As used herein, where the context clearly indicates that the term “signal” refers to a wireless signal or RF signal, an RF signal may also be referred to as a “wireless signal” or simply a “signal.”

[0037] Various aspects of the systems and technologies described herein will be discussed below with reference to the accompanying drawings. According to these aspects, Figure 1 An example of a wireless communication system 100 is illustrated. The wireless communication system 100 (e.g., also referred to as a wireless wide area network (WWAN)) may include individual base stations 102 and individual UEs 104. In some aspects, base station 102 may also be referred to as a "network entity" or "network node". One or more of base stations 102 may be implemented in an aggregated or monolithic base station architecture. Additionally or alternatively, one or more of base stations 102 may be implemented in a decomposed base station architecture and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC. Base station 102 may include macrocell base stations (e.g., high-power cellular base stations) and / or small cell base stations (e.g., low-power cellular base stations). On the one hand, macro cell base stations may include eNB and / or ng-eNB (where wireless communication system 100 corresponds to a Long Term Evolution (LTE) network), or gNB (where wireless communication system 100 corresponds to an NR network), or a combination of both, and small cell base stations may include femtocells, picocells, microcells, etc.

[0038] Base station 102 can collectively form a RAN and interface with core network 170 (e.g., evolved packet core (EPC) or 5G core (5GC)) via backhaul link 122, and interface with one or more location servers 172 via core network 170 (e.g., the one or more location servers may be part of core network 170 or may be outside core network 170). Among other functions, base station 102 can perform functions related to one or more of the following: delivering user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, location, and delivery of warning messages. Base station 102 can communicate with each other directly or indirectly (e.g., via EPC or 5GC) via backhaul link 134 (which may be wired and / or wireless).

[0039] Base station 102 can wirelessly communicate with UE 104. Each base station in base station 102 can provide communication coverage for a corresponding geographical coverage area 110. In one aspect, base station 102 in each coverage area 110 can support one or more cells. A “cell” is a logical communication entity used to communicate with a base station (e.g., on a frequency resource, referred to as a carrier frequency, component carrier, carrier, frequency band, etc.) and can be associated with an identifier (e.g., Physical Cell Identifier (PCI), Virtual Cell Identifier (VCI), Cell Global Identifier (CGI)) to distinguish cells operating via the same or different carrier frequencies. In some cases, different cells can be configured according to different protocol types that can provide access for different types of UEs (e.g., Machine Type Communication (MTC), Narrowband IoT (NB-IoT), Enhanced Mobile Broadband (eMBB), or other protocol types). Because a cell is supported by a specific base station, the term “cell” can refer to either or both of the logical communication entity and the base station supporting the logical communication entity, depending on the context. Furthermore, since the TRP is typically the physical transmission point of a cell, the terms “cell” and “TRP” can be used interchangeably. In some cases, the term "cell" can also refer to the geographic coverage area of ​​a base station (e.g., a sector), as long as the carrier frequency can be detected and used for communication within a portion of the geographic coverage area 110.

[0040] While the geographic coverage areas 110 of adjacent macro cell base stations 102 may partially overlap (e.g., in handover areas), some areas within geographic coverage areas 110 may substantially overlap with larger geographic coverage areas 110. For example, a small cell base station 102' may have a coverage area 110' that substantially overlaps with the coverage areas 110 of one or more macro cell base stations 102. A network that includes both small cell base stations and macro cell base stations can be referred to as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB) that can provide service to a restricted group referred to as a Closed Subscriber Group (CSG).

[0041] The communication link 120 between base station 102 and UE 104 may include uplink (e.g., also referred to as the reverse link) transmission from UE 104 to base station 102 and / or downlink (e.g., also referred to as the forward link) transmission from base station 102 to UE 104. The communication link 120 may use MIMO antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. One or more carrier frequencies may be used to provide the communication link 120. Carrier allocation may be asymmetric with respect to the downlink and uplink (e.g., more or fewer carriers may be allocated to the downlink compared to the uplink).

[0042] Beamforming (also known as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting or receiving device (e.g., one or more of base station 102, UE 104, etc.) to shape or guide an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting and receiving devices. Beamforming can be implemented by combining signals transmitted via antenna elements of an antenna array such that some signals propagating relative to a particular orientation of the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to the signals transmitted via the antenna elements may include applying amplitude shifts, phase shifts, or both to the signals carried via the antenna elements associated with the device by the transmitting or receiving device. The adjustments associated with each of these antenna elements may be defined by a beamforming weight set associated with a particular direction (e.g., relative to the antenna array of the transmitting or receiving device or relative to some other direction).

[0043] Transmitting and / or receiving devices (e.g., one or more such as base station 102 and / or UE 104) may use beam scanning technology as part of beamforming operations. For example, base station 102 (e.g., or other transmitting devices) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 104 (e.g., or other receiving devices). Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by base station 102 (or other transmitting devices) in different directions. For example, base station 102 may transmit signals according to different beamforming weight sets associated with different transmission directions. Transmission in different beam directions may be used to identify (e.g., by transmitting devices such as base station 102, or by receiving devices such as UE 104) beam directions so that base station 102 may transmit or receive later.

[0044] Some signals (such as data signals associated with a specific receiving device) may be transmitted by base station 102 in a single beam direction (e.g., the direction associated with the receiving device, such as UE 104). In some examples, the beam direction associated with transmission along a single beam direction may be determined based on the signals transmitted in one or more beam directions. For example, UE 104 may receive one or more signals transmitted by base station 102 in different directions, and may report to base station 104 an indication of signals received by UE 104 with the highest signal quality or other acceptable signal quality.

[0045] In some examples, transmissions performed by a device (e.g., by base station 102 or UE 104) may be performed using multiple beam directions, and the device may use a combination of digital pre-decoding or radio frequency beamforming to generate combined beams for transmission (e.g., from base station 102 to UE 104, from transmitting device to receiving device, etc.). UE 104 may report feedback indicating pre-decoding weights for one or more beam directions, and this feedback may correspond to a configured number of beams across system bandwidth or one or more subbands. Base station 102 may transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), etc.), which may or may not be pre-decoded. UE 104 may provide feedback for beam selection, which may be a pre-decoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel codebook, linear combination codebook, port selection codebook). Although these techniques are described with reference to signals transmitted by base station 102 in one or more directions, UE 104 may employ similar techniques to transmit signals multiple times in different directions (e.g., to identify beam direction for subsequent transmission or reception by UE 104), or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0046] A receiving device (e.g., UE 104) may attempt multiple receiving configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 102. For example, the receiving device may attempt multiple receiving directions by: receiving via different antenna subarrays; processing the received signal according to different antenna subarrays; receiving according to different sets of receiving beamforming weights applied to signals received at multiple antenna elements of the antenna array (e.g., different directional listening weight sets); or processing the received signal according to different sets of receiving beamforming weights applied to signals received at multiple antenna elements of the antenna array. Any of these may be referred to as “listening” according to different receiving configurations or receiving directions. In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when a data signal is received). The single receiving configuration may be aligned on a beam direction determined based on listening according to different receiving configuration directions (e.g., based on listening according to multiple beam directions and determining that it has the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality).

[0047] The wireless communication system 100 may also include a WLAN AP 150 communicating with a WLAN station (STA) 152 via a communication link 154 in unlicensed spectrum (e.g., 5 GHz). When communicating in unlicensed spectrum, the WLAN STA 152 and / or WLAN AP 150 may perform a Free Channel Assessment (CCA) or Listen-After-Talk (LBT) process before communication to determine if the channel is available. In some examples, the wireless communication system 100 may include devices (e.g., UEs, etc.) that communicate with one or more UEs 104, base stations 102, APs 150, etc., using ultra-wideband (UWB) spectrum. The UWB spectrum can range from 3.1 GHz to 10.5 GHz.

[0048] Small cell base station 102' can operate in licensed and / or unlicensed spectrum. When operating in unlicensed spectrum, small cell base station 102' can employ LTE or NR technology and use the same 5 GHz unlicensed spectrum as WLAN AP 150. Small cell base station 102' employing LTE and / or 5G in unlicensed spectrum can enhance coverage of the access network and / or increase the capacity of the access network. NR in unlicensed spectrum can be referred to as NR-U. LTE in unlicensed spectrum can be referred to as LTE-U, Licensed Assisted Access (LAA), or MulteFire.

[0049] The wireless communication system 100 may also include a millimeter-wave (mmW) base station 180, which can operate at mmW and / or near-mmW frequencies to communicate with the UE 182. The mmW base station 180 may be implemented in a converged or monolithic base station architecture, or alternatively, in a decomposed base station architecture (e.g., including one or more of a CU, DU, RU, near-RT RIC, or non-RT RIC). Extremely high frequency (EHF) is a portion of the electromagnetic spectrum that contains radio frequency (RF). EHF has a range of 30 GHz to 300 GHz with wavelengths between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-mmW can extend down to frequencies of 3 GHz with wavelengths of 100 mm. Ultra-high frequency (SHF) bands extend between 3 GHz and 30 GHz, and are also referred to as centimeter waves. Communication using mmW and / or near-mmW radio bands has high path loss and relatively short range. mmW base station 180 and UE 182 can utilize beamforming (e.g., transmission and / or reception) on mmW communication link 184 to compensate for extremely high path loss and short range. Furthermore, it should be understood that in alternative configurations, one or more base stations 102 may also use mmW or near-mmW and beamforming for transmission. Therefore, it should be understood that the foregoing illustrations are merely examples and should not be construed as limiting the various aspects disclosed herein.

[0050] In some aspects related to 5G, the spectrum in which wireless network nodes or entities (e.g., base stations 102 / 180, UE 104 / 182) operate is divided into multiple frequency ranges: FR1 (e.g., from 450 MHz to 6,000 MHz), FR2 (e.g., from 24,250 MHz to 52,600 MHz), FR3 (e.g., above 52,600 MHz), and FR4 (e.g., between FR1 and FR2). In multi-carrier systems such as 5G, one of the carrier frequencies is referred to as the “primary carrier” or “anchor carrier” or “primary serving cell” or “PCell,” and the remaining carrier frequencies are referred to as “secondary carriers” or “secondary serving cells” or “SCell.” In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) used by UE 104 / 182 and the cell, where UE 104 / 182 performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure in that cell. The primary carrier carries all common control channels as well as UE-specific control channels and can be a carrier on a licensed frequency (however, this is not always the case). The secondary carrier is a carrier operating on a second frequency (e.g., FR2) that can be configured and used to provide additional radio resources once an RRC connection is established between UE 104 and the anchor carrier. In some cases, the secondary carrier can be a carrier on an unlicensed frequency. The secondary carrier may contain only the necessary signaling information and signals; for example, since the primary uplink and primary downlink carriers are typically UE-specific, those UE-specific signaling information and signals may not be present on the secondary carrier. This means that different UEs 104 / 182 in a cell can have different downlink primary carriers. The same applies to the uplink primary carrier. The network can change the primary carrier of any UE 104 / 182 at any time. This is done, for example, to balance the load on different carriers. Since a “serving cell” (e.g., whether it is a PCell or a SCell) corresponds to a carrier frequency and / or component carrier that some base stations are using for communication, the terms “cell”, “serving cell”, “component carrier”, “carrier frequency”, etc. can be used interchangeably.

[0051] For example, still refer to Figure 1One of the frequencies used by macro cell base station 102 may be an anchor carrier (or "PCell"), and the other frequencies used by macro cell base station 102 and / or mmW base station 180 may be secondary carriers ("SCell"). In carrier aggregation, each carrier of base station 102 and / or UE 104 may use up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz) of spectrum, with up to a total of Yx MHz (e.g., x component carriers) for transmission in each direction. Component carriers may or may not be adjacent to each other in the spectrum. Carrier allocation may be asymmetrical with respect to downlink and uplink (e.g., more or fewer carriers may be allocated to downlink compared to uplink). Simultaneous transmission and / or reception on multiple carriers allows UE 104 / 182 to significantly increase its data transmission and / or reception rates. For example, two aggregated 20 MHz carriers in a multi-carrier system would theoretically result in a doubling of the data rate (e.g., 40 MHz) compared to the data rate obtained by a single 20 MHz carrier.

[0052] To operate on multiple carrier frequencies, base station 102 and / or UE 104 may be equipped with multiple receivers and / or transmitters. For example, UE 104 may have two receivers, namely "Receiver 1" and "Receiver 2", where "Receiver 1" is a multi-band receiver that can be tuned to band "X" or band "Y", while "Receiver 2" is a single-band receiver that can be tuned to only band "Z". In this example, if UE 104 is being served in band "X", then band "X" will be referred to as PCell or active carrier frequency, and "Receiver 1" will need to tune from band "X" to band "Y" (e.g., SCell) to measure band "Y" (and vice versa). In contrast, regardless of whether UE 104 is being served in band "X" or band "Y", due to the separate "Receiver 2", UE 104 can measure band "Z" without interrupting service on band "X" or band "Y".

[0053] The wireless communication system 100 may also include a UE 164, which can communicate with the macro cell base station 102 on the communication link 120 and / or with the mmW base station 180 on the mmW communication link 184. For example, the macro cell base station 102 may support PCells and one or more SCells for the UE 164, and the mmW base station 180 may support one or more SCells for the UE 164.

[0054] The wireless communication system 100 may also include one or more UEs, such as UE 190, which are indirectly connected to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (e.g., referred to as "side links"). Figure 1 In one example, UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of the base stations 102 (e.g., UE 190 can indirectly obtain cellular connectivity through this link), and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (e.g., UE 190 can indirectly obtain WLAN-based Internet connectivity through this link). In one example, D2D P2P links 192 and 194 can use any known D2D RAT (such as LTE Direct (LTE-D), Wi-Fi Direct (Wi-Fi-D), Bluetooth). ® (etc.) to support.

[0055] Figure 2 A block diagram illustrating an example architecture 200 for a base station 102 and a UE 104 according to some aspects of this disclosure is provided, which enables the transmission and processing of signals exchanged between the UE and the base station. Example architecture 200 includes components of base station 102 and UE 104, which may be... Figure 1 The illustrated base station 102 includes one base station and the UE 104 includes one UE. The base station 102 may be equipped with T antennas 234a to 234t, and the UE 104 may be equipped with R antennas 252a to 252r, wherein typically T ≥ 1 and R ≥ 1.

[0056] At base station 102, transmitting processor 220 can receive data for one or more UEs from data source 212, select one or more modulation and decoding schemes (MCS) for each UE based on a channel quality indicator (CQI) received from each UE, process (e.g., encode and modulate) the data for each UE based on the selected MCS, and provide data symbols for all UEs. Transmitting processor 220 can also process system information (e.g., semi-static resource allocation information (SRPI) and control information (e.g., CQI requests, grants, and / or upper-layer signaling) and provide overhead symbols and control symbols. Transmitting processor 220 can also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signal (PSS) and secondary synchronization signal (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 can perform spatial processing (e.g., pre-decoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, where applicable, and can provide T output symbol streams to T modulators (MODs) 232a to 232t. Modulators 232a to 232t are shown as combined modulator-demodulators (MOD-DEMODs). In some cases, the modulators and demodulators can be separate components. Each modulator in modulators 232a to 232t can process a corresponding output symbol stream (e.g., for an orthogonal frequency division multiplexing (OFDM) scheme, etc.) to obtain an output sample stream. Each modulator in modulators 232a to 232t can further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals can be transmitted from modulators 232a to 232t via T antennas 234a to 234t, respectively. Based on some aspects described in more detail below, position coding can be used to generate synchronization signals to transmit additional information.

[0057] At UE 104, antennas 252a to 252r can receive downlink signals from base station 102 and / or other base stations, and can provide the received signals to one or more demodulators (DEMODs) 254a to 254r respectively. Demodulators 254a to 254r are shown as combined modulator-demodulators (MOD-DEMODs). In some cases, the modulator and demodulator can be separate components. Each demodulator in 254a to 254r can adjust (e.g., filter, amplify, down-convert, and digitize) the received signal to obtain an input sample. Each demodulator in 254a to 254r can further process the input sample (e.g., for OFDM, etc.) to obtain the received symbols. MIMO detector 256 can obtain the received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols where applicable, and provide the detected symbols. The receiver processor 258 can process (e.g., demodulate and decode) the detected symbols, provide the decoded data for UE 104 to the data sink 260, and provide the decoded control information and system information to the controller / processor 280. The channel processor can determine the Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), Reference Signal Received Quality (RSRQ), and / or Channel Quality Indicator (CQI), etc.

[0058] On the uplink, at UE 104, the transmitting processor 264 can receive and process data from data source 262 and control information from controller / processor 280 (e.g., reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmitting processor 264 can also generate reference symbols for one or more reference signals (e.g., based on β values ​​or sets of β values ​​associated with the one or more reference signals). The symbols from the transmitting processor 264 can be pre-decoded by the TX MIMO processor 266, further processed by modulators 254a to 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to base station 102. At base station 102, uplink signals from UE 104 and other UEs can be received by antennas 234a to 234t, processed by demodulators 232a to 232t, detected by MIMO detector 236 (e.g., where applicable), and further processed by receiver processor 238 to obtain decoded data and control information transmitted by UE 104. Receiver processor 238 can provide the decoded data to data sink 239 and the decoded control information to controller (e.g., processor) 240. Base station 102 may include communication unit 244 and communicate with network controller 231 via communication unit 244. Network controller 231 may include communication unit 294, controller / processor 290, and memory 292.

[0059] In some respects, one or more components of UE 104 may be included in the housing. These include the controller 240 of base station 102, the controller / processor 280 of UE 104, and / or Figure 2 Any other component may perform one or more techniques associated with the implicit UCI β value determination for NR.

[0060] Memory 242 and 282 may store data and program code for base station 102 and UE 104, respectively. Scheduler 246 may schedule UE for data transmission on downlink, uplink and / or sidelink.

[0061] In some respects, the deployment of communication systems (such as 5G New Radio (NR) systems) can involve a variety of components or constituent parts. In a 5G NR system or network, network nodes, network entities, network mobility elements, radio access network (RAN) nodes, core network nodes, network elements or network equipment (such as base stations (BS)), or one or more units (or components) performing base station functionality can be implemented in aggregated or decomposed architectures. For example, a BS (e.g., such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), transmit / receive point (TRP), or cell, etc.) can be implemented as an aggregated base station (e.g., also referred to as a standalone BS or monolithic BS) or a decomposed base station.

[0062] Aggregated base stations can be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. Decentralized base stations can be configured to utilize a protocol stack that is physically or logically distributed across two or more units (e.g., one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs)). In some aspects, the CU may be implemented within a RAN node, and one or more DUs may co-located with the CU, or alternatively, may be geographically or virtually distributed across one or more other RAN nodes. DUs may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may also be implemented as a virtual unit, namely a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0063] Base station type operation or network design can take into account the aggregation characteristics of base station functionality. For example, decomposed base stations can be used in integrated access backhaul (IAB) networks, open radio access networks (O-RAN (e.g., network configurations such as those initiated by the O-RAN Alliance)), or virtualized radio access networks (e.g., vRAN, also known as cloud radio access networks (C-RAN)). Decomposition can include distributing functionality across two or more units in various physical locations, as well as virtually distributing the functionality of at least one unit, which allows for flexibility in network design. The various units in a decomposed base station or decomposed RAN architecture can be configured for wired or wireless communication with at least one other unit.

[0064] Figure 3 This is an illustration of an example decomposed base station 300 architecture. The decomposed base station 300 architecture may include one or more CUs 310, which may communicate directly with the core network 320 via a backhaul link, or indirectly with the core network 320 via one or more decomposed base station units (e.g., a near real-time (near RT) RAN Intelligent Controller (RIC) 325 via an E2 link, or a non-real-time (non-RT) RIC 315 associated with a Service Management and Orchestration (SMO) framework 305, or both). CUs 310 may communicate with one or more distributed units (DUs) 330 via corresponding midhaul links (e.g., F1 interfaces). DUs 330 may communicate with one or more radio units (RUs) 340 via corresponding fronthaul links. RUs 340 may communicate with corresponding UEs 104 via one or more radio frequency (RF) access links. In some implementations, UE 104 may be served simultaneously by multiple RUs 340.

[0065] Figure 3Each of the units shown and / or described herein (e.g., CU 310, DU 330, RU340, and near-RT RIC 325, non-RT RIC 315, and SMO frame 305) may include one or more interfaces, or may be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via wired or wireless transmission media. Each unit, or an associated processor or controller providing instructions to the communication interfaces of these units, may be configured to communicate with one or more other units via transmission media. For example, these units may include wired interfaces configured to receive signals or transmit signals to one or more other units via wired transmission media. Additionally, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (e.g., a radio frequency (RF) transceiver) configured to receive signals or transmit signals to one or more other units, or both, via a wireless transmission media.

[0066] In some aspects, the CU 310 can host one or more higher-level control functions. Such control functions may include Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), Serving Data Adaptation Protocol (SDAP), etc. Each control function can be implemented using an interface configured to signal to other control functions hosted by the CU 310. The CU 310 can be configured to handle user plane functions (e.g., Central Unit-User Plane (CU-UP)), control plane functions (e.g., Central Unit-Control Plane (CU-CP)), or combinations thereof. In some implementations, the CU 310 can be logically divided into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP units can communicate bidirectionally with the CU-CP units via an interface such as an E1 interface. The CU 310 can be implemented to communicate with the DU 330 for network control and signaling, as needed.

[0067] DU 330 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RU 340s. In some aspects, DU 330 may host one or more of the Radio Link Control (RLC) layer, the Media Access Control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending on a functional partition (e.g., such as that defined by the 3rd Generation Partnership Project (3GPP)). In some aspects, DU 330 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface configured to communicate signals with other layers (and modules) hosted by DU 330 or with control functions hosted by CU 310.

[0068] Lower-layer functionality can be implemented by one or more RU 340s. In some deployments, an RU340 controlled by a DU 330 may correspond to a logical node that hosts RF processing functions or low-PHY layer functions (e.g., performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, Physical Random Access Channel (PRACH) extraction and filtering, or both) based on functional decomposition (such as lower-layer functional decomposition). In such architectures, the RU 340 may be implemented to handle over-the-air (OTA) communications with one or more UE 104s. In some specific implementations, the real-time and non-real-time aspects of control plane and user plane communications with the RU 340 may be controlled by the corresponding DU 330. In some scenarios, this configuration enables the DU 330 and CU 310 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0069] SMO framework 305 can be configured to support RAN deployment and provisioning of both non-virtualized and virtualized network elements. For non-virtualized network elements, SMO framework 305 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which can be managed via operation and maintenance interfaces (e.g., such as the O1 interface). For virtualized network elements, SMO framework 305 can be configured to interact with a cloud computing platform (e.g., such as Open Cloud (O-Cloud) 390) to perform network element lifecycle management (e.g., such as instantiating virtualized network elements) via a cloud computing platform interface (e.g., such as the O2 interface). Such virtualized network elements may include, but are not limited to, CU 310, DU 330, RU 340, and near-RTRIC 325. In some specific implementations, SMO framework 305 can communicate with the hardware aspects of the 4G RAN (e.g., such as the Open eNB (O-eNB) 311) via the O1 interface. Additionally, in some implementations, the SMO framework 305 may communicate directly with one or more RUs 340 via an O1 interface. The SMO framework 305 may also include a non-RT RIC 315 configured to support the functionality of the SMO framework 305.

[0070] The non-RT RIC 315 can be configured to include logical functions that enable non-real-time control and optimization of RAN elements and resources, including artificial intelligence / machine learning (AI / ML) workflows for model training and updates, or policy-based guidance for applications / features in the near-RT RIC 325. The non-RT RIC 315 can be coupled to or communicate with the near-RT RIC 325, for example, via an A1 interface. The near-RT RIC 325 can be configured to include logical functions that enable near real-time control and optimization of RAN elements and resources via an interface, for example, via an E2 interface, through data collection and actions that connect one or more CU 310s, one or more DU 330s, or both, and O-eNBs to the near-RT RIC 325.

[0071] In some implementations, to generate AI / ML models to be deployed in the near-RT RIC 325, the non-RT RIC 315 may receive parameters or external enrichment information from an external server. This information can be utilized by the near-RT RIC 325 and may be received from non-network data sources or network functions at the SMO framework 305 or the non-RT RIC 315. In some examples, the non-RT RIC 315 or near-RT RIC 325 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 315 may monitor long-term trends and patterns in performance and employ AI / ML models to perform corrective actions via the SMO framework 305 (e.g., reconfiguration via O1) or via the creation of RAN management policies (e.g., A1 policies).

[0072] Figure 4 An example of a computing system 470 for a wireless device 407 is illustrated. The wireless device 407 may include client devices such as UEs (e.g., UE 104, UE 152, UE 190) or other types of devices usable by an end user (e.g., a station (STA) configured to communicate using a Wi-Fi interface). For example, the wireless device 407 may include mobile phones, routers, tablet computers, laptop computers, tracking devices, wearable devices (e.g., smartwatches, glasses, extended reality (XR) devices such as virtual reality (VR), augmented reality (AR), or mixed reality (MR) devices), Internet of Things (IoT) devices, vehicles, aircraft, and / or another device configured to communicate via a wireless communication network. The computing system 470 includes software and hardware components that may be electrically coupled or communicatively coupled (e.g., or may otherwise communicate, as applicable) via a bus 489. For example, the computing system 470 includes one or more processors 484. One or more processors 484 may include one or more CPUs, ASICs, FPGAs, APs, GPUs, VPUs, NSPs, microcontrollers, special-purpose hardware, any combination thereof, and / or other processing devices or systems. One or more processors 484 may use bus 489 to communicate between cores and / or with one or more memory devices 486.

[0073] The computing system 470 may also include one or more memory devices 486, one or more digital signal processors (DSPs) 482, one or more SIMs 474, one or more modems 476, one or more wireless transceivers 478, antennas 487, one or more input devices 472 (e.g., camera, mouse, keyboard, touchscreen, touchpad, keypad and / or microphone, etc.) and one or more output devices 480 (e.g., display, speaker and / or printer, etc.).

[0074] In some aspects, computing system 470 may include one or more RF interfaces configured to transmit and / or receive radio frequency (RF) signals. In some examples, the RF interface may include components such as modem 476, wireless transceiver 478, and / or antenna 487. One or more wireless transceivers 478 may transmit and receive wireless signals (e.g., signal 488) from one or more other devices via antenna 487, such as other wireless devices, network devices (e.g., base stations such as eNBs and / or gNBs, Wi-Fi access points (APs) such as routers or range extenders, etc.), and / or cloud networks, etc. In some examples, computing system 470 may include multiple antennas or antenna arrays that facilitate simultaneous transmission and reception functionality. Antenna 487 may be an omnidirectional antenna, allowing radio frequency (RF) signals to be received and transmitted in all directions. Wireless signal 488 may be transmitted via a wireless network. The wireless network may be any wireless network, such as cellular or telecommunications networks (e.g., 3G, 4G, 5G, etc.), wireless local area networks (e.g., Wi-Fi networks), Bluetooth, etc. ™ Networks and / or other networks.

[0075] In some examples, wireless signal 488 can be transmitted directly to other wireless devices using sidelink communication (e.g., using a PC5 interface, using a DSRC interface, etc.). Wireless transceiver 478 can be configured to transmit RF signals via antenna 487 for performing sidelink communication according to one or more transmit power parameters that can be associated with one or more regulated modes. Wireless transceiver 478 can also be configured to receive sidelink communication signals with different signal parameters from other wireless devices.

[0076] In some examples, one or more wireless transceivers 478 may include an RF front end, which includes one or more components such as amplifiers, mixers for down-conversion of signals (e.g., also referred to as signal multipliers), frequency synthesizers (e.g., also referred to as oscillators) that supply signals to the mixers, baseband filters, analog-to-digital converters (ADCs), one or more power amplifiers, and other components. The RF front end typically handles the selection of wireless signals 488 and the conversion of wireless signals to baseband frequencies or intermediate frequencies, and can convert RF signals to the digital domain.

[0077] In some cases, computing system 470 may include a decoder-decoder device (or codec) configured to encode and / or decode data transmitted and / or received using one or more wireless transceivers 478. In some cases, computing system 470 may include an encryption-decryption device or component configured (e.g., according to AES and / or DES standards) to encrypt and / or decrypt data transmitted and / or received by one or more wireless transceivers 478.

[0078] One or more SIMs 474 may each securely store an International Mobile Subscriber Identity (IMSI) number and associated key assigned to a user of a wireless device 407. The IMSI and key can be used to identify and authenticate the subscriber when accessing a network provided by a network service provider or operator associated with one or more SIMs 474. One or more modems 476 may modulate one or more signals to encode information to be transmitted using one or more wireless transceivers 478. One or more modems 476 may also demodulate signals received by one or more wireless transceivers 478 to decode the transmitted information. In some examples, one or more modems 476 may include a Wi-Fi modem, a 4G (or LTE) modem, a 5G (or NR) modem, and / or other types of modems. One or more modems 476 and one or more wireless transceivers 478 may be used to transmit data from one or more SIMs 474.

[0079] The computing system 470 may also include one or more non-transitory machine-readable storage media or storage devices (e.g., one or more memory devices 486) (and / or communicate with them), which may include, but are not limited to, local and / or network-accessible storage devices, disk drives, drive arrays, optical storage devices, solid-state storage devices such as RAM and / or ROM, which may be programmable, flash-updatable, etc. Such storage devices may be configured to implement any suitable data storage, including but not limited to various file systems and / or database structures.

[0080] In various aspects, functionality may be stored in memory device 486 as one or more computer program products (e.g., instructions or code) and executed by one or more processors 484 and / or one or more DSPs 482. Computing system 470 may also include software elements (e.g., residing within one or more memory devices 486) including, for example, operating systems, device drivers, executable libraries, and / or other code, such as one or more applications that may include computer programs implementing the functionality provided by various aspects, and / or may be designed to implement methods and / or configure systems as described herein.

[0081] Figure 5This is an illustration of an example architecture for a radio frequency (RF) energy harvesting device 500 (e.g., a passive device) that can be used to provide sample-level orthogonal frequency OFDM backscattering. As will be described in more detail below, the RF energy harvesting device 500 can harvest RF energy from one or more RF signals received using antenna 590. As used herein, the term "energy harvesting" may be used interchangeably with "power harvesting." In some aspects, an "energy harvesting device" can be a device capable of performing energy harvesting (EH). For example, as used herein, the term "energy harvesting device" may be used interchangeably with the terms "device with EH capability" or "device with energy harvesting capability." In some aspects, the energy harvesting device 500 can be implemented as an Internet of Things (IoT) device, or as a sensor, etc., as will be described in more detail below. In other examples, the energy harvesting device 500 can be implemented as a radio frequency identification (RFID) tag or various other RFID devices.

[0082] Energy harvesting device 500 includes one or more antennas 590 that can be used to transmit and receive one or more wireless signals. For example, energy harvesting device 500 can use antennas 590 to receive one or more downlink signals and transmit one or more uplink signals. Impedance matching component 510 can be used to match the impedance of antenna 590 with the impedance of one or more (or all) receiving components included in energy harvesting device 500. In some examples, the receiving components of energy harvesting device 500 may include demodulator 520 (e.g., for demodulating received downlink signals), energy harvester 530 (e.g., for harvesting RF energy from received downlink signals), regulator 540, microcontroller unit (MCU) 550, and modulator 560 (e.g., for generating uplink signals). In some cases, the receiving components of energy harvesting device 500 may also include one or more sensors 570.

[0083] Downlink signals can be received from one or more transmitters. For example, energy harvesting device 500 can receive downlink signals from network nodes or network entities included in the same wireless network as energy harvesting device 500. In some cases, the network entity can be a base station, gNB, etc., that communicates with energy harvesting device 500 using a cellular communication network. For example, the cellular communication network can be implemented according to 3G, 4G, 5G and / or other cellular standards (e.g., including future standards such as 6G and above).

[0084] In some cases, the energy harvesting device 500 may be implemented as a passive or semi-passive energy harvesting device (also referred to as a passive or semi-passive device) that performs passive uplink communication by modulating and reflecting downlink signals received via antenna 590. The passive or semi-passive energy harvesting device may also be referred to as a passive or semi-passive device with EH capability, respectively. For example, passive and semi-passive energy harvesting devices may not be able to generate and transmit uplink signals without first receiving a modulated and reflected downlink signal. In other examples, the energy harvesting device 500 may be implemented as an active energy harvesting device that utilizes a powered transceiver to perform active uplink communication. The active energy harvesting device is capable of generating and transmitting uplink signals without first receiving a downlink signal (e.g., by using a power source on the device to power its powered transceiver).

[0085] Active or semi-passive energy harvesting devices (e.g., also referred to as active devices with EH capability or semi-passive devices with EH capability, respectively) may include one or more energy storage elements 585 (e.g., collectively referred to as “energy storage devices”). For example, one or more energy storage elements 585 may include batteries, capacitors, etc. In some examples, one or more energy storage elements 585 may be associated with a boost converter 580. The boost converter 580 may receive at least a portion of the energy harvested by the energy harvester 530 as input (e.g., the remainder of the harvested energy is provided as instantaneous power for operating the energy harvesting device 500). In some aspects, the boost converter 580 may be a boost converter that increases the voltage from its input to its output (e.g., and decreases the current from its input to its output). In some examples, the boost converter 580 may be used to increase the harvested energy generated by the energy harvester 530 to a voltage level associated with charging one or more energy storage elements 585. Active or semi-passive energy harvesting devices may include one or more energy storage elements 585 and may include one or more boost converters 580. The number of energy storage elements 585 may be the same as or different from the number of boost converters 580 included in an active or semi-passive energy harvesting device.

[0086] Passive energy harvesting devices (e.g., also referred to as “passive devices with EH capability” or “passive devices”) do not include a power source on the energy storage element 585 or other equipment. For example, a passive energy harvesting device may be powered solely using RF energy harvested from a downlink signal (e.g., using energy harvester 530). As previously mentioned, a semi-passive energy harvesting device may include one or more energy storage elements 585 and / or a power source on other equipment. The energy storage element 585 of a semi-passive energy harvesting device can be used to supplement or complement the RF energy harvested from the downlink signal. In some cases, the energy stored in the energy storage element 585 of a semi-passive energy harvesting device may be insufficient to transmit uplink communication without first receiving downlink communication (e.g., the minimum transmit power of the semi-passive device > the capacity of the energy storage element). Active energy harvesting devices may include one or more energy storage elements 585 and / or a power source on other equipment that can power uplink communication without using supplemented harvested RF energy (e.g., the minimum transmit power of the active device < the capacity of the energy storage element). Energy storage element 585, included in active energy harvesting devices and / or semi-passive energy harvesting devices, can be charged using the harvested RF energy.

[0087] As mentioned above, passive and semi-passive energy harvesting devices transmit uplink communication by performing backscatter modulation to modulate and reflect the received downlink signal. The received downlink signal is used to provide both power (e.g., for demodulation, local processing, and modulation) and a carrier wave for uplink communication (e.g., for reflection of the downlink signal). For example, a portion of the downlink signal will be backscattered as an uplink signal, while the remainder of the downlink signal can be used to perform energy harvesting.

[0088] Active energy harvesting devices can transmit uplink communication without performing backscatter modulation and without receiving a corresponding downlink signal (e.g., an active energy harvesting device includes an energy storage element for providing power and a powered transceiver for generating a carrier wave for uplink communication). Passive and semi-passive energy harvesting devices cannot transmit uplink signals in the absence of a downlink signal (e.g., passive communication). Active energy harvesting devices do not depend on receiving a downlink signal to transmit uplink signals and can transmit uplink signals as needed (e.g., active communication).

[0089] In an example where energy harvesting device 500 is implemented as a passive or semi-passive energy harvesting device, antenna 590 can be used to receive a continuous carrier downlink signal and modulate (e.g., remodulate) it for uplink communication. In some cases, modulator 560 can be used to modulate the reflected (e.g., backscattered) portion of the downlink signal. For example, the continuous carrier can be a continuous sine wave (e.g., a sine or cosine waveform), and modulator 560 can perform modulation based on changing one or more of the amplitude and phase of the backscattered reflection. Based on the modulation of the backscattered reflection, modulator 560 can encode digital symbols (e.g., binary symbols or more complex symbol systems) indicating uplink communication or data messages. For example, uplink communication can indicate sensor data or other information associated with one or more sensors 570 included in energy harvesting device 500.

[0090] As previously mentioned, impedance matching component 510 can be used to match the impedance of antenna 590 with the receiving components of energy harvesting device 500 when receiving downlink signals (e.g., when receiving a continuous carrier). In some examples, during backscatter operation (e.g., when transmitting uplink signals), modulation can be performed based on an intentional mismatch of the antenna input impedance so that a portion of the incident downlink signal is scattered back. The phase and amplitude of the backscatter reflection can be determined based on the impedance load on antenna 590. Based on changing the antenna impedance (e.g., changing the impedance mismatch between antenna 590 and the remaining components of energy harvesting device 500), digital symbols and / or binary information can be encoded (e.g., modulated) onto the backscatter reflection. Modulator 560 can be used to perform the change of antenna impedance to modulate the phase and / or amplitude of the backscatter reflection.

[0091] like Figure 5As illustrated, a portion of the downlink signal received using antenna 590 can be provided to demodulator 520, which performs demodulation and provides downlink communication (e.g., carried or modulated on the downlink signal) to microcontroller unit (MCU) 550 or other processor included in energy harvesting device 500. The remaining portion of the downlink signal received using antenna 590 can be provided to energy harvester 530, which harvests RF energy from the downlink signal. For example, energy harvester 530 can harvest RF energy based on performing AC-to-DC (alternating current to direct current) conversion, where an AC current is generated from a sinusoidal carrier of the downlink signal and the converted DC current is used to power energy harvesting device 500. In some aspects, energy harvester 530 may include one or more rectifiers for performing AC-to-DC conversion. The rectifier may include one or more diodes or thin-film transistors (TFTs). In one exemplary example, energy harvester 530 may include one or more Schottky diode-based rectifiers. In some cases, energy harvester 530 may include one or more TFT-based rectifiers.

[0092] The output of energy harvester 530 is a DC current generated (e.g., collected) from a portion of the downlink signal supplied to energy harvester 530. In some aspects, the DC current output of energy harvester 530 may vary with the input supplied to energy harvester 530. For example, an increase in the input current to energy harvester 530 may be associated with an increase in the output DC current generated by energy harvester 530. In some cases, MCU 550 may be associated with a narrow band of acceptable DC current values. Regulator 540 may be used to eliminate or otherwise reduce variations in the DC current generated by the output of energy harvester 530. For example, regulator 540 may eliminate or smooth spikes (e.g., increases) in the DC current output by energy harvester 530 (e.g., such that the DC current supplied as input to MCU 550 by regulator 540 remains below a first threshold). In some cases, regulator 540 may eliminate or otherwise compensate for a decrease or reduction in the DC current output by energy harvester 530 (e.g., such that the DC current supplied as input to MCU 550 by regulator 540 remains above a second threshold).

[0093] In some respects, the collected DC current (e.g., generated by energy harvester 530 and regulated up or down by regulator 530 as needed) can be used to power MCU 550 and one or more additional components included in energy harvesting device 500. For example, the collected DC current can be additionally used to power one or more (or all) of impedance matching 510, demodulator 520, regulator 540, MCU 550, sensor 570, modulator 560, etc. For example, sensor 570 and modulator 560 can receive at least a portion of the collected DC current remaining after MCU 550 (e.g., not consumed by MCU 550). In some cases, the collected DC current output by regulator 540 can be provided to MCU 550, modulator 560, and sensor 570 in series, parallel, or a combination thereof.

[0094] In some examples, sensor 570 can be used to acquire sensor data (e.g., sensor data such as sensor data associated with the environment in which energy harvesting device 500 is located). Sensor 570 may include one or more sensors, which may be of the same or different types. In some aspects, one or more (or all) of sensors 570 may be configured to acquire sensor data based on control information included in a downlink signal received using antenna 590. For example, one or more of sensors 570 may be configured based on downlink communication that is acquired based on demodulating the received downlink signal using demodulator 520. In an exemplary example, sensor data may be transmitted based on the backscatter reflection of a continuous carrier received at antenna 590 using modulator 560 (e.g., changing one or more of its amplitude and / or phase). Based on the modulation of the backscatter reflection, modulator 560 may encode digital symbols (e.g., binary symbols or more complex symbol systems) indicating uplink communication or data messages. In some examples, modulator 560 may generate an uplink backscatter modulated signal based on sensor data received directly from sensor 570. In some examples, modulator 560 may generate an uplink backscatter modulated signal based on sensor data received from MCU 550 (e.g., based on MCU 550 receiving sensor data directly from sensor 570).

[0095] As previously mentioned, AIoT (e.g., passive IoT) technology has recently garnered significant attention in the industry (e.g., within 3GPP). Currently, research is underway on 3GPP Release 19 SA 1 SID for IoT devices with ambient power enabled, and a 3GPP RAN plenary study entitled "New SID: Study on Ambient IoT" has been approved in RP-222685.

[0096] AIoT devices (e.g., passive devices) are ultra-low complexity and ultra-low power devices, significantly reducing complexity and power consumption compared to existing active IoT devices. Type A devices (such as passive devices (e.g., AIoT devices)) are battery-free devices with no energy storage capacity and rely entirely on the availability of an external energy source (e.g., for RF energy harvesting). Type B devices (such as semi-passive IoT devices) have limited energy storage (e.g., supercapacity energy storage or conventional capacity energy storage) that does not require manual replacement or recharging.

[0097] AIoT devices (such as tags, backscatter UEs (BUEs), or passive UEs (PUEs)) are typically passive devices without active RF components. PUEs can perform data transmission based on modulating incident RF signals emitted by ambient transmitters (such as base stations or UEs). Ambient RF signals can be used as both a signal resource for backscattering and an energy resource for energy harvesting by the device.

[0098] RFID tags are an existing battery-free technology. However, RFID tags have the drawback of a limited read range of only a few meters, which can make it difficult to support large-scale deployment of RFID tags with seamless coverage. Therefore, new designs for IoT devices that enable environmental power in NR may be useful.

[0099] Figure 6 and Figure 7 Examples of different deployment scenarios for AIoT devices are shown. Specifically, Figure 6 Figure 600 illustrates example single-site deployment scenarios 605a, 605b for passive devices 620 (e.g., AIoT devices). Figure 6 In the single-site deployment scenario 605a, a network device 610 (e.g., a base station in the form of a gNB) and a passive device 620 (e.g., an AIoT device in the form of an AIoT UE, such as an RFID tag) are shown. The network device 610 can operate as a reader using full-duplex (FD). During operation of the single-site deployment scenario 605a, the network device 610 can transmit a continuous wave (CW) to the passive device 620 via a forward link (FL). The passive device 620 can receive the CW from the network device 610 and can transmit a backscattered signal based on the CW via a backscattered link (BL). The FL can also carry control signaling to the passive device 620, and the BL can carry data from the passive device 620 (e.g., tag data, such as RFID tag data). The CW can be used as a power source for the passive device 620 and as a carrier signal for backscattered communication from the passive device 620. The passive device 620 can generate the backscattered signal (e.g., the BL) by modulating the incoming CW from the network device 610.

[0100] Figure 6 Single-site deployment scenario 605b illustrates a network device 630 (e.g., a UE in the form of a smartphone) and a passive device 620 (e.g., an AIoT device in the form of an AIoT UE). The network device 630 can operate as a reader using a FD. During operation of single-site deployment scenario 605b, the network device 630 can send a CW and a FL to the passive device 620. The passive device 620 can receive the CW and FL from the network device 630 and can send a BL based on the CW. The FL can carry control signaling to the passive device 620. The BL can carry data from the passive device 620. The CW can serve as a power source for the passive device 620 and a carrier signal for backscattered communication from the passive device 620. The passive device 620 can generate a backscattered signal (e.g., the BL) by modulating the incoming CW from the network device 630.

[0101] Figure 7 This is illustration 700 illustrating example dual-site deployment scenarios 705a, 705b, 705c, and 705d for passive devices 720 (e.g., AIoT devices). Figure 7 In the dual-site deployment scenarios 705a, 705b, 705c, and 705d, network device 710 (e.g., a base station in the form of a gNB), network device 730 (e.g., a UE in the form of a smartphone), and passive device 720 (e.g., an AIoT device in the form of an AIoT UE, such as an RFID tag) are each shown. Network device 710 and network device 730 can each operate as a reader using half-duplex (HD).

[0102] During operation in a dual-site deployment scenario 705a, network device 710 can send CW and FL to passive device 720. Passive device 720 can receive CW and FL from network device 710 and can send BL, such as a backscatter signal, to network device 730 based on the CW. FL can carry control signaling to passive device 720, and BL can carry data from passive device 720 (e.g., tag data, such as RFID tag data). CW can be used as a power source for passive device 720 and as a carrier signal for backscatter communication from passive device 720. Passive device 720 can generate a backscatter signal (e.g., BL) by modulating the incoming CW from network device 710. Network device 730 can receive BL from passive device 720 and can (e.g., via a Uu link) send communication signals (e.g., which may include information within the BL) to network device 710 and receive such communication signals from network device 710.

[0103] During operation in a dual-site deployment scenario 705b, network device 730 can send CW and FL to passive device 720. Passive device 720 can receive CW and FL from network device 730 and can send BL, such as a backscatter signal, to network device 710 based on the CW. Passive device 720 can generate a backscatter signal (e.g., BL) by modulating the incoming CW from network device 730. Network device 710 can receive the BL from passive device 720 and can (e.g., via a Uu link) send communication signals (e.g., which may include information within the BL) to network device 730 and receive such communication signals from network device 730.

[0104] During operation in a dual-site deployment scenario 705c, network device 710 can send a communication wave (CW) to passive device 720. Network device 730 can send a backscatter signal (FL) to passive device 720. Passive device 720 can receive FL from network device 730. Passive device 720 can also receive CW from network device 710 and can send a backscatter signal (BL), such as a backscattered signal, to network device 730 based on the CW. Passive device 720 can generate a backscattered signal (e.g., BL) by modulating the incoming CW from network device 710. Network device 730 can receive BL from passive device 720 and can (e.g., via a Uu link) send communication signals (e.g., which may include information within the BL) to network device 710 and receive such communication signals from network device 710.

[0105] During operation in a dual-site deployment scenario 705d, network device 730 can send a communication wave (CW) to passive device 720. Network device 710 can send a backscatter signal (FL) to passive device 720. Passive device 720 can receive FL from network device 710. Passive device 720 can also receive CW from network device 730 and can send a backscatter signal (BL), such as a backscattered signal, to network device 710 based on the CW. Passive device 720 can generate a backscattered signal (e.g., BL) by modulating the incoming CW from network device 730. Network device 710 can receive BL from passive device 720 and can (e.g., via a Uu link) send communication signals (e.g., which may include information within the BL) to network device 730 and receive such communication signals from network device 730.

[0106] In backscatter communication, information transmission can be performed using antenna modulation without involving active RF generation. Backscatter devices (e.g., passive devices, such as AIoT devices) can modulate the incoming RF signal by intentionally switching the load impedance within the device to change the amplitude and / or phase of the backscatter signal (e.g., to decode the backscatter signal). For example, with amplitude shift keying (ASK), a passive device can switch the value of the load impedance between a very high impedance and a relatively matched load. When the load impedance is switched to a very high impedance, the mismatch between the antenna impedance and the load impedance causes all the power in the received signal to be reflected back to the reader in the backscatter signal. When the load impedance is switched to a relatively matched load, most of the power from the incoming RF signal is absorbed within the device, and very little power is reflected back to the reader in the backscatter signal.

[0107] Frequency-switching impedance can produce a frequency shift in the incident signal (e.g., the baseband frequency can be shifted by Δ frequency). It can help separate the backscattered signal from the incident RF signal in the frequency domain and minimize mutual interference.

[0108] Figure 8 An example of backscatter communication is shown, where the backscattered signal is amplitude modulated. Specifically, Figure 8 This is a diagram illustrating an example of a system 800 used for performing backscatter communication. Figure 8 The diagram illustrates a network device 810 (e.g., a base station or UE) operating as a reader and a passive device 850 (e.g., an AIoT device, such as an RFID tag) operating as a backscattering device. The network device 810 includes a transmitter (Tx) 820 and a receiver (Rx) 830. The passive device 850 includes an antenna, an RF energy harvesting unit 860, a microcontroller 870, a switch 880, and multiple loads 890 (Z1, Z2, ... Z...). N In one or more examples, the passive device 850 may generate a backscattered signal that is frequency-modulated and / or phase-modulated instead of amplitude-modulated, such as Figure 8 As shown.

[0109] During operation for backscatter communication, the transmitter 820 of network device 810 can transmit an RF wave (continuous wave or ambient NR OFDM signal) 840 to passive device 850. Passive device 850 can receive the RF wave (continuous wave or ambient NR OFDM signal) 840 via an antenna. RF energy harvesting unit 860 can harvest energy from the received RF wave (continuous wave or ambient NR OFDM signal) 840. Microcontroller 870 can control switch 880 to switch load 890 in various different configurations to modulate data onto the backscatter signal 895 using amplitude modulation accordingly.

[0110] When the antenna of passive device 850 receives power When an RF wave (e.g., continuous wave or ambient NR OFDM signal 840) is emitted, power is transmitted from the antenna to the load (e.g., load 890), and a portion of the power will be reflected by the reflection coefficient. (Kurokawa formula) Power reflected from the load to the antenna. Then radiated from the antenna after reflection. .

[0111] The passive device 850 can then send a modulated backscatter signal 895 to the network device 810. The receiver 830 of the network device 810 can receive the modulated backscatter signal 895 and can decode the modulated backscatter signal 895 to retrieve data from the passive device 850.

[0112] For backscattering from passive devices (e.g., RFID devices), a dedicated RF transmitter (e.g., a dedicated transmitter) is required to send a sinusoidal signal as the RF wave used for backscatter transmission. Using a sinusoidal signal as the carrier may occupy additional space within the spectrum, and deploying a dedicated RF transmitter near the passive device may increase the cost and complexity of the system.

[0113] In one or more examples, backscattering of an OFDM signal can be used instead of a sinusoidal signal. For symbol-level backscattering, the amplitude, phase, or frequency of the ambient OFDM signal (e.g., an NR signal and / or channel) can be modulated on a symbol basis. For example, the bit data (BD) symbol period can be an integer multiple of the OFDM symbol period. In one or more examples, backscattering can embed one (1) bit of data for each or more OFDM symbols (e.g., for an NR FR1 with a 15 kHz or 30 kHz subcarrier spacing (SCS), a maximum data rate of 14 or 28 kilobits per second can be achieved).

[0114] Figure 9 An example of symbol-level backscattering is shown, in which the amplitude, phase, or frequency of an ambient OFDM signal (e.g., an NR signal and / or a channel) is modulated on a symbol basis. Specifically, Figure 9 Figure 900 shows examples 905a, 905b, and 905c of symbol-level OFDM backscattering. Figure 9 Example 905a of symbol-level OFDM backscattering using amplitude shift keying (ASK) is shown. In example 905a, multiplier 930 can multiply RF signal 920 (e.g., OFDM signal transmitted from a network device such as a base station or UE) including NR OFDM symbols (e.g., symbol n and symbol m) with tag data 910 (e.g., bit 0 or bit 1) to generate a backscattered signal, which is associated with different reflection powers using ASK, wherein the switching frequency of the backscattering state is equal to the OFDM symbol rate.

[0115] Figure 9 Example 905b of symbol-level OFDM backscattering using phase shift keying (PSK) is also shown. In example 905b, multiplier 930 can multiply RF signal 920 (e.g., OFDM signal transmitted from a network device such as a base station or UE) including NR OFDM symbols (e.g., symbol n and symbol m) with tag data 910 (e.g., bit 0 or bit 1) to generate a backscattered signal, which is associated with a square wave having a different initial phase (e.g., zero degrees or 180 degrees) using PSK, wherein the frequency of the square wave is equal to the OFDM sampling rate.

[0116] exist Figure 9 Example 905c of symbol-level OFDM backscattering using Frequency Shift Keying (FSK) is also shown. In example 905c, multiplier 930 can multiply RF signal 920 (e.g., OFDM signal transmitted from a network device such as a base station or UE) including NR OFDM symbols (e.g., symbol n and symbol m) with tag data 910 (e.g., bit 0 or bit 1) to generate a backscattered signal, which tag data is associated with square waves of different frequencies (e.g., f0 and f1) using FSK.

[0117] In one or more aspects, to increase the data rate (e.g., for NR FR1 with a 15 kHz or 30 kHz subcarrier spacing, symbol-level OFDM backscattering has a lower maximum data rate of 14 or 28 kilobits per second, and a higher data rate can be achieved by using a larger subcarrier spacing, such as 60 kHz), sample-level OFDM backscattering can be employed. In one or more examples, square waves with different initial phases can be used to modulate the phase of samples in the OFDM signal to embed tag data (e.g., by adjusting the tag data from...). and (Change phase). As long as the switch (e.g., Figure 8The switching frequency of the switch (880) is high enough that the backscattered signal does not overlap with the OFDM signal in the frequency domain, and a filter can be used at the receiver (e.g., reader device) to separate the backscattered signal from the OFDM signal to demodulate the tag data.

[0118] Figure 10 An example of symbol-level OFDM backscattering is shown. Specifically, Figure 10 This is a diagram illustrating an example of forming a backscattered signal 1030 based on an OFDM signal 1010. Figure 10 The diagram illustrates an OFDM signal 1010, a tag switch configuration 1020 for tag data (e.g., on or off), and a backscatter signal 1030. The backscatter signal is shown as comprising an OFDM signal with a frequency carrier (fc) and a baseband signal. The phase of the different square waves associated with the tag switch configuration 1020 can indicate tag data (e.g., 0 bits or 1 bit).

[0119] exist Figure 10 In order to form the backscattered signal 1030, the phase of the sample of the OFDM signal 1010 may (or may not) be changed according to the tag switch configuration 1020 (e.g., tag data). For example, when the tag switch configuration 1020 has a square wave with a phase of zero degrees, the phase of the sample of the OFDM signal 1010 does not change with respect to the backscattered signal 1030. However, when the tag switch configuration 1020 has a square wave with a phase of 180 degrees, the phase of the sample of the OFDM signal 1010 changes by 180 degrees with respect to the backscattered signal 1030.

[0120] In one or more examples, the Fourier series can be used to represent the th... Fang Bo: , in It is a square wave frequency. Let m be the initial phase of the square wave and m be the order of the harmonics. It can be observed that even-order harmonics (e.g., m = 2, 4, 6, ...) are all zero. Higher odd-order harmonics (e.g., m = 5, 7, ...) decay rapidly with increasing order and can therefore be ignored. If we assume that the third harmonic can be eliminated through specific implementation, then we can assume that the backscattered data is carried only by the first harmonic (e.g., m = 1) cosine wave in the Fourier series. In such a case, sample-level modulation can be achieved by... Given that the backscattered sample is far from the original frequency shift in frequency. In order to minimize mutual interference.

[0121] In one or more examples, the backscattered signal received at the reader (e.g., a network device, such as in the form of a base station (e.g., a gNB)) can be represented (in the time domain) by the following formula: , in It is the OFDM signal received at the tag (e.g., passive device, such as AIoT UE, such as RFID tag); It is a tag data signal; and These are the forward link (FL) channel from the RF source (e.g., a network device, such as a UE (e.g., a smartphone)) to the tag and the backscatter link (BL) channel from the tag to the reader; and It is the channel delay; and the symbol This represents the convolution operation between two signals.

[0122] The corresponding frequency domain (FD) signal can be represented by the following formula: Due to convolution operations, the received signal on subcarrier k includes not only the transmitted signal on subcarrier k, but also signals from other subcarriers. Due to unknown... It also includes non-idealities caused by timing and frequency errors at the tag, estimating the backscatter channel. This can be challenging for reader receivers, and coherent detection cannot be applied to tag data demodulation.

[0123] For OFDM backscattering, it is desirable that existing OFDM receivers can be used to receive backscattered signals and process tag data. Decoding requires that the received FD signal can be re-formulated as... It can be proven that the above content is only valid under the following conditions.

[0124] - Case 1: The FL link has a single path, i.e. - Scenario 2: It is constant within the OFDM symbol, and - Case 3: The OFDM signal has only a single tone. In one or more examples, channel estimation problems may exist when a single-tone OFDM signal s(t) is used as the source signal for a passive device. In one or more examples, for a single-tone OFDM signal (e.g., ,in Otherwise, the value is 0, and the frequency domain backscattered signal can be re-formulated as: Will need to know the combined channel For use with tag data Decoding is then performed. That is, the frequency of the backscattered signal needs to be estimated. FL channels and frequencies Multiplication of BL channels on the above However, the pitch can only be estimated from the DMRS of the OFDM signal. For sample-level backscattering, It is not a constant, and if Used for If an approximation is made, the performance (e.g., channel estimation) will degrade, especially when the delay spread of the BL channel is large.

[0125] Figure 11 This is a diagram illustrating an example of a bistationary deployment scenario 1100 with backscattered signals based on single-tone OFDM signals 1140a and 1140b. Figure 11 In the dual-site deployment scenario 1100 (e.g., a system), it is shown to include network device 1130 (e.g., a base station in the form of a gNB), network device 1110 (e.g., a UE in the form of a smartphone), and passive device 1120 (e.g., an AIoT device in the form of an AIoT UE, such as an RFID tag). Network device 1130 and network device 1110 can each operate as a reader using half-duplex (HD).

[0126] exist Figure 11 During the operation of the dual-site deployment scenario 1100, network device 1110 can send a single-tone OFDM signal 1140a s(t) to passive device 1120 via the forward link FL h(t). Passive device 1120 can receive the single-tone OFDM signal 1140a s(t) from network device 1110 via FL h(t). Passive device 1120 can send a backscattered signal 1160a to network device 1130 via the backscattered link BL g(t) based on the modulated incoming OFDM signal and the tag baseband signal 1150a x(t). The backscattered signal 1160a can be represented in the time domain as follows: FL can carry control signaling to passive device 1120. BL can carry data from passive device 1120 (e.g., tag data, such as RFID tag data). A single-tone OFDM 1140a s(t) in CW form can be used as a power source for passive device 1120 and a carrier signal for backscatter communication from passive device 1120. Passive device 1120 can generate a backscatter signal 1160a (e.g., BL) by modulating the incoming OFDM from network device 11130. Network device 1130 can receive the backscatter signal from passive device 1120. .

[0127] Figure 11 Correlated signals in the frequency domain are also shown. Examples include the single-tone OFDM 1140b S(f), the tag baseband signal 1150b X(f), and the received FD backscattered signal 1160b. All are shown in the frequency domain. The monotone OFDM 1140b S(f) is shown as having frequency... The tag baseband signal 1150b X(f) with a bandwidth of 2B is shown as having a frequency The received backscattered signal 1160b is shown as also having a bandwidth of 2B. The received backscattered signal 1160b is shown as having an offset to The frequency.

[0128] This system and technology provide sample-level OFDM backscattering for AIoT devices, such as passive devices like RFID tags. In one or more aspects, the system and technology involve modifying the backscattering technique to enable reuse of OFDM waveforms and receivers. In one or more examples, the system and technology employ sample-level OFDM backscattering to increase the data rate of IoT devices in the environment. However, in some cases, sample-level OFDM backscattering can lead to channel estimation errors on the reader side. The system and technology provide solutions to minimize these potential errors.

[0129] In one or more aspects, the backscatter packet may include a continuous square wave with a time-varying frequency, a preamble, and a payload. The continuous square wave may be associated with one or more OFDM DMRS symbols, and the time-varying frequency of the continuous square wave produces multiple frequency shifts in the DMRS of the incident OFDM signal, which can help the reader receiver estimate the backscatter channel. This is used for decoding tag data. A preamble (e.g., which may be predetermined to indicate the timing of the OFDM signal and is known to the receiver) can be used by the receiver (e.g., a reader) to locate the start of the backscattered sample relative to the OFDM symbol boundary in the OFDM signal.

[0130] In one or more examples, the backscattered signal transmitted by a passive device (e.g., a tag) may comprise three parts: a continuous square wave (CSW) with a time-varying frequency, followed by a preamble and a payload. The CSW and preamble are associated with the DMRS symbol of the OFDM signal. The CSW is a series of square waves without any embedded tag data and consists of multiple frequencies. Composition, in which 2, ..., and This indicates the subcarrier spacing (SCS) of OFDM. It has frequency... The square wave will cause the DMRS tone of the OFDM signal to change from frequency. Shift to frequency This allows the receiver to estimate the channel on the frequency-shifted DMRS tone. .

[0131] In one or more examples, frequency shift sets This can be configured based on the tag data (e.g., depending on the tag data rate). In some examples, the frequency shift set... It can be configured based on the bandwidth of the tag data (e.g., frequency shift set). This can be configured to correspond to the bandwidth of the tag data (e.g., the tag signal bandwidth). Therefore, the effective tag data spectrum can be limited to... Single frequency It can be used in CSW (e.g., when the tag data rate is low). For CSW The adaptation can be performed on the OFDM symbol boundary (e.g., using a backscattering method for the first OFDM symbol). and used for backscattering OFDM symbols Or within OFDM, such as through all within an OFDM symbol. (Switch).

[0132] Following the CSW, the tag can send its data bits to the receiver. The data bits may include a specialized preamble and a payload, where the preamble can be used by the receiver to find the start of the tag data relative to the OFDM symbol boundary to address any potential timing errors at the tag.

[0133] OFDM signals can be single tones with a cyclic prefix. Tags can be backscattered by modulating the phase of OFDM samples to include the preamble and payload, where modulation can be achieved by a frequency-dependent modulator. Square wave control.

[0134] In one or more examples, the tag (e.g., a passive network device) can modulate a portion of the OFDM symbol of the OFDM signal. In some examples, the length of the portion of the OFDM symbol can be configured depending on the residual timing error at the tag (e.g., the passive network device).

[0135] Figure 12 An example of a backscattering group including the CSW, preamble, and payload is shown. Specifically, Figure 12 This is a diagram illustrating an example of a first configuration 1200 for a backscattered signal used in symbol-level OFDM backscattering. Figure 12 In the diagram, OFDM signal 1210 and tag signal 1220 (e.g., including tag data) are shown in the time domain. OFDM signal 1210 is shown as including a plurality of OFDM symbols 1230, which may be DMRS symbols or data symbols. Tag signal 1220 is shown as including a tag signal with a time-varying frequency (e.g., frequency f). 0、… f K The CSW, preamble (e.g., bit sequence), and payload.

[0136] exist Figure 12 The OFDM signal 1240 and tag signal 1250 are also shown in the frequency domain. The OFDM signal 1390 includes OFDM symbols 1260 as DMRS symbols and data symbols, which are modulated using tag data for backscattered signals.

[0137] In one or more aspects, backscatter packets may include a preamble and a payload. The DMRS tone (subcarrier) of an OFDM signal can be divided into multiple segments, with zero-power subcarriers located between these segments. The reader can estimate both the channel and timing offset based on the shifted DMRS tone.

[0138] In one or more examples, if the OFDM signal is excited using a specific DMRS mode, the backscattered signal transmitted by a passive device (e.g., a tag) may include a preamble and a payload, but not the preceding continuous square wave (CSW) before the preamble begins. The DMRS subcarriers (tones) of the OFDM signal may be mapped to discontinuous subcarriers, with zero-power subcarriers between the discontinuous DMRS subcarriers.

[0139] In one or more examples, a DMRS subcarrier may be mapped to one of every N subcarriers, with the other subcarriers having zero power (ZP). In some examples, a DMRS subcarrier may each comprise M discontinuous segments, each segment containing multiple DMRS tones.

[0140] In one or more examples, the number of zero-power subcarriers located between DMRS subcarriers can be configurable and large enough that the convolution of one DMRS tone (or DMRS segment) with the tag data does not overlap with the convolution of another DMRS tone (or another DMRS segment) with the tag data. Therefore, It can be assumed that it is the same for each DMRS segment, if For each segment being identical, the receiver can pick up (e.g., receive) a DMRS tone from each segment and estimate the backscatter channel. Unknown A common weighting factor can be introduced into the estimated backscatter channel. This common weighting factor can be corrected during time-domain processing of the tag data based on the known tag preamble.

[0141] Figure 13 An example of a backscattered packet including a preamble and a payload is shown. Specifically, Figure 13 This is a diagram illustrating an example of a second configuration 1300 for backscattered signals used in symbol-level OFDM backscattering. Figure 13 In the diagram, OFDM signal 1310 and tag signal 1320 (e.g., tag data) are shown in the time domain. OFDM signal 1310 includes a plurality of OFDM symbols 1330, which may be DMRS symbols or data symbols. Tag signal 1320 (e.g., tag data) is shown as including a preamble (e.g., a bit sequence) and a payload.

[0142] exist Figure 13 In the frequency domain, OFDM signal 1340 and backscattered signal 1350 are shown. The frequency f is shown. c The OFDM signal 1340 is centered on a data symbol and a DMRS symbol, which are frequency-shifted (e.g., shifted to frequency f). c +fs) and modulated using tag data 1320 for backscatter signal 1350. The DMRS subcarriers (tones) of OFDM signal 1340 are shown as mapped to discontinuous subcarriers, and zero-power (ZP) subcarriers are located between the discontinuous DMRS subcarriers.

[0143] In one or more respects, as previously mentioned, the DMRS of an OFDM signal can be mapped to one subcarrier out of every N subcarriers, with the other subcarriers having zero power (ZP). In one or more examples, the DMRS can be mapped to subcarriers. , , ,in The frequency domain (FD) density used for DMRS tone mapping is indicated and determined by the associated backscatter data rate. In some examples, the value of N can be 4, 6, 12, or 24, corresponding to a density of 3, 2, 1, or 0.5 DMRS tones per resource block (RB). In one or more examples, for a density equal to 0.5, a bit may be included to indicate whether the DMRS occupies an odd or even number of resource blocks (RBs). The DMRS sequence can be a ZC sequence as an older sequence.

[0144] Figure 14 Examples of DMRS tone patterns with different FD densities are shown. Specifically, Figure 14 This is a diagram illustrating an example of a mode for a DMRS subcarrier (tone) used in OFDM signals. Figure 14 The diagram shows a resource block (RB) 1400, where the x-axis represents time and the y-axis represents frequency. RB 1400 includes multiple DMRS tones (e.g., including DMRS tone 1410) and multiple subcarriers with zero power (e.g., including subcarrier 1420 with zero power).

[0145] In RB 1400, each row shows a different DMRS tone pattern. For example, the first row of RB 1400 shows a DMRS tone pattern that includes a DMRS tone separated from each other by three subcarriers with zero power. The second row of RB 1400 shows a DMRS tone pattern that includes a DMRS tone separated from each other by five subcarriers with zero power.

[0146] In one or more aspects, as previously mentioned, DMRS subcarriers may each comprise M discontinuous segments, with zero-power subcarriers between these segments. In one or more examples, each segment may comprise multiple contiguous subcarriers, and the segment size may be configurable (e.g., 2, 3, 4, 6, 12, or 24 subcarriers). In some examples, the number of zero-power subcarriers between segments may also be configurable (e.g., 3, 5, 11, or 23 subcarriers), which may depend on the backscatter data rate of the passive device (e.g., environmental IoT).

[0147] In one or more examples, each segment may share the same base sequence (e.g., the same DMRS sequence) with or without additional phase scrambling. For example, the same base sequence may be repeated for each segment. In another example, phase randomization may be applied to the base sequence before mapping to the segments. In one or more examples, assume a Zadoff-Chu (ZC) sequence of length K. Where K is the number of DMRS pitches in each segment, for the _th DMRS fragments can be derived from Given, among which It is the phase scrambling coefficient.

[0148] Figure 15 Figure 1500 illustrates an example of an OFDM signal divided into multiple segments 1520, specifically a DMRS subcarrier (e.g., a data subcarrier 1510). Figure 15 In the diagram, the x-axis represents frequency. Data subcarrier 1510 (e.g., DMRS subcarrier) is shown spanning the OFDM signal bandwidth 1530 in frequency. Data subcarrier 1510 (e.g., DMRS subcarrier) is divided into multiple DMRS segments 1520. DMRS segments 1520 are separated from each other by zero-power (ZP) subcarriers 1540. Some scrambling is shown as applied to each DMRS segment within DMRS segment 1520. Figure 15 In the diagram, each DMRS segment is shown as using a different scrambling sequence (e.g., C0, C1, C2, ... C). M-1 and C M-2 Scrambling is performed.

[0149] In one or more aspects, to address potential synchronization errors at passive devices (e.g., tags), only a portion of the OFDM symbols of the OFDM signal is modulated to carry tag data (e.g., the middle portion of each OFDM symbol). A number of samples can be used for backscatter modulation, and the remaining samples and CP of each OFDM symbol are filled with continuous square waves (CSW) without any embedded tag data. In one or more examples, the network device (e.g., a base station, such as a gNB) can indicate to the tag the length of a portion of the OFDM symbol adapted based on the estimated synchronization error. For example, for A small quantity can be used for initial transmissions with large synchronization errors, and The value can be increased for subsequent transmissions, where it can be based on a timing offset estimate from previous transmissions (e.g., This provides timing advance commands to the tag, and the residual timing error at the passive device is reduced.

[0150] In some respects, Figure 15 In OFDM signals, the data subcarriers can be divided into multiple segments. For example, besides... Figure 15 In addition to segmenting the DMRS tone, the data subcarrier 1510 can also be segmented. In this respect, when the OFDM signal is used as a carrier signal for backscatter communication, the OFDM signal can be mapped to multiple discontinuous segments.

[0151] Figure 16 The middle section of each OFDM symbol 1610a, 1610b is shown. The sample size is used for an example of backscatter modulation, where the remaining samples of each OFDM symbol and CP 1620 are filled with continuous square waves (CSW) without any embedded tag data. Specifically, Figure 16 This is a diagram illustrating an example configuration 1600 for a backscattered signal used in symbol-level OFDM backscattering. Figure 16 The image shows two OFDM symbols 1610a and 1610b. Each OFDM symbol 1610a and 1610b includes a CP 1620 and a data symbol 1630. The middle portion of each data symbol 1630 is shown as including backscattered data 1640, while the remaining portion of data symbol 1630 and CP 1620 are shown as including a continuous square wave (CSW) without any embedded tag data.

[0152] In one or more aspects, passive devices (e.g., tags) can be dynamically instructed (e.g., by a reader, such as a base station or UE) whether to insert a symbol of a continuous square wave before backscattering the tag data. For example, whether to include dynamic switching between CSWs before the preamble can be based on the type of OFDM signal used.

[0153] In one or more aspects, the waveform of the OFDM signal can be based on DFT-s-OFDM. In some examples, the OFDM signal can be a Physical Uplink Shared Channel (PUSCH) using one or two preceding DMRS symbols, where the remaining resource elements (REs) are not used for DMRS in symbols not used for any PUSCH data transmission. The OFDM signal can also be an Uplink (UL) Sound Reference Signal (SRS) followed by a PUSCH, where the SRS and PUSCH are transmitted in the same bandwidth (BW) with the same beam and / or pre-decoder and transmit power. In one or more examples, legacy ULSRS patterns can be reused (e.g., with a comb tooth count of 2 or 4, or with a new RB-level comb tooth pattern to support high tag data rates).

[0154] In one or more aspects, passive devices (e.g., tags) may also be indicated (e.g., by a reader, such as a base station or UE) to have a backscatter symbol rate, which may be defined by the number of tag bits to be backscattered in an OFDM symbol. In one or more examples, the number of tag bits within an OFDM symbol may also be one. In this case, codeword conversion may be used (e.g., using codeword 0 to represent 0 and using another codeword 1 to represent 1), and for non-codeword-based methods, all tag data values ​​within an OFDM symbol must not be a sequence of all "1"s or all "0"s.

[0155] Figure 17This is a flowchart illustrating an example of a process 1700 for providing sample-level OFDM backscattering for environmental IoT devices (e.g., RFID tags or other passive devices or environmental IoT devices). Process 1700 may be provided by passive network devices (e.g., RFID tags or other passive devices or environmental IoT devices, such as...) Figure 5 RF energy harvesting device 500, Figure 6 AIoT UE 620 Figure 7 AIoT UE 720 or Figure 8 The backscattering device 850 or any other network device) or a component or system of a passive network device (e.g., a chipset) performs the operation. The operation of process 1700 can be implemented in one or more processors (e.g., Figure 18 Software components executed and running on the processor 1810 or other processor. Furthermore, the transmission and reception of signals by the network device in process 1700 can be, for example, by one or more antennas and / or one or more transceivers (such as one or more wireless transceivers) (e.g., receiver, transmitter, and / or one or more of the transceivers). Figure 18 This is achieved through the communication interface 1840 and / or other antennas and / or transceivers.

[0156] At box 1710, a passive network device (or a component thereof) can receive orthogonal frequency division multiplexing (OFDM) signals from a network device (e.g., a base station such as a gNB, user equipment (UE), or other network device). In some aspects, the demodulation reference signal (DMRS) subcarriers of the OFDM signal are mapped across multiple segments. In some examples, one or more zero-power (ZP) subcarriers are located between corresponding segment pairs of multiple segments from the DMRS subcarriers, such as... Figure 15 As shown. In some cases, each of the multiple segments may include the same base sequence. In some cases, each of the multiple segments includes a sequence generated by applying phase randomization to the base sequence. In some aspects, the OFDM signal is a single tone and includes a cyclic prefix (CP). In some aspects, the OFDM signal includes one or more preloaded DMRS symbols.

[0157] At box 1720, a passive network device (or a component thereof) may transmit (or cause the transmission of) a backscattered signal based on an OFDM signal, the backscattered signal comprising a frequency of the OFDM signal shifted to a non-overlapping frequency. In some aspects, the backscattered signal may include a preamble and a payload, such as Figure 12 and Figure 13As shown. For example, a preamble can indicate the start of a backscattered sample relative to the OFDM symbol boundary within the OFDM signal. In some cases, the backscattered signal also includes a continuous square wave (CSW) with a time-varying frequency, such as... Figure 12 and Figure 16 As shown. For example, a continuous square wave can precede the preamble in the backscattered signal. In some cases, the frequency of the continuous square wave can be configured depending on at least one of the tag data rate or the tag signal bandwidth. In some cases, a continuous square wave with a time-varying frequency generates multiple frequency shifts in the demodulation reference signal (DMRS) subcarrier of the OFDM signal.

[0158] In some respects, passive network devices (or components thereof) can modulate a portion of the OFDM symbol of an OFDM signal. In some cases, the length of a portion of the OFDM symbol can be configured depending on the residual timing error at the passive network device.

[0159] In some examples, the processes described herein (e.g., process 1700 and / or other processes described herein) may be performed by computing devices or apparatuses (e.g., network devices, such as RFID tags or other passive devices or environmental IoT devices). For example, as noted above, one or more of the processes described herein (e.g., process 1700 and / or other processes described herein) may be performed by energy harvesting devices (e.g., devices with EH capability). In some examples, one or more of the processes described herein (e.g., process 1700 and / or other processes described herein) may be performed by a device with... Figure 5 The device architecture shown is the same as or similar to the EH-capable device architecture, and the device execution is also EH-capable.

[0160] In some cases, a computing device or apparatus may include various components such as one or more input devices, one or more output devices, one or more processors, one or more microprocessors, one or more microcomputers, one or more cameras, one or more sensors, and / or other components configured to perform the steps of the processes described herein. In some examples, a computing device may include a display, one or more network interfaces configured to transmit and / or receive data, any combination thereof, and / or other components. One or more network interfaces may be configured to transmit and / or receive wired and / or wireless data, including data according to 3G, 4G, 5G, and / or other cellular standards, data according to the WiFi (802.11x) standard, and data according to Bluetooth. ™ Standard data, data according to the Internet Protocol (IP) standard, and / or other types of data.

[0161] Components of a computing device may be implemented in circuitry. For example, components may include electronic circuitry or other electronic hardware, and / or may be implemented using electronic circuitry or other electronic hardware, which may include one or more programmable electronic circuits (e.g., a microprocessor, graphics processing unit (GPU), digital signal processor (DSP), central processing unit (CPU), and / or other suitable electronic circuitry), and / or may include computer software, firmware, or any combination thereof for performing the various operations described herein, and / or may be implemented using computer software, firmware, or any combination thereof for performing the various operations described herein.

[0162] Process 1700 is illustrated as a logic flowchart, the operations of which represent a sequence of operations that can be implemented in hardware, computer instructions, or combinations thereof. In the context of computer instructions, each operation represents a computer-executable instruction stored on one or more computer-readable storage media that, when executed by one or more processors, performs the described operation. Generally, computer-executable instructions include routines, programs, objects, components, data structures, etc., that perform a particular function or implement a particular data type. The order in which the operations are described is not intended to be construed as limiting, and any number of described operations can be combined in any order and / or in parallel to implement the process.

[0163] Additionally, process 1700 and / or other processes described herein may be executed under the control of one or more computer systems configured using executable instructions, and may be implemented as code (e.g., executable instructions, one or more computer programs, or one or more applications) that executes jointly on one or more processors, by hardware, or a combination thereof. As noted above, the code may be stored on a computer-readable or machine-readable storage medium, for example, in the form of a computer program comprising multiple instructions executable by one or more processors. The computer-readable or machine-readable storage medium may be non-transitory.

[0164] Figure 18 This is a diagram illustrating an example of a system used to implement certain aspects of this technology. Specifically, Figure 18 An example of computing system 1800 is illustrated. This computing system can be any computing device, such as constituting an internal computing system, a remote computing system, a camera, or any component thereof, wherein the components of the system communicate with each other using connection 1805. Connection 1805 can be a physical connection using a bus, or a direct connection to processor 1810, as in a chipset architecture. Connection 1805 can also be a virtual connection, a networking connection, or a logical connection.

[0165] In some aspects, computing system 1800 is a distributed system in which the functions described in this disclosure can be distributed across a data center, multiple data centers, a peer-to-peer network, etc. In some aspects, one or more system components described represent a number of such components that each perform some or all of the functions described for that component. In some aspects, components can be physical or virtual devices.

[0166] Example system 1800 includes at least one processing unit (CPU or processor) 1810 and a connection 1805 that communicatively couples various system components, including system memories 1815 such as read-only memory (ROM) 1820 and random access memory (RAM) 1825, to the processor 1810. Computing system 1800 may include a cache 1815 of high-speed memory that is directly connected to, closely proximates, or integrated into the processor 1810.

[0167] Processor 1810 may include any general-purpose processor and hardware or software services, such as services 1832, 1834, and 1836 stored in storage device 1830, which are configured to control processor 1810 and dedicated processors in which software instructions are incorporated into the actual processor design. Processor 1810 may be a substantially completely independent computing system containing multiple cores or processors, buses, memory controllers, caches, etc. Multi-core processors may be symmetric or asymmetric.

[0168] To enable user interaction, the computing system 1800 includes an input device 1845 that can represent any number of input mechanisms, such as a microphone for voice, a touch-sensitive screen for gesture or graphic input, a keyboard, a mouse, motion input, and voice input. The computing system 1800 may also include an output device 1835 that can be one or more of a plurality of output mechanisms. In some cases, a multimodal system allows the user to provide multiple types of input / output to communicate with the computing system 1800.

[0169] The computing system 1800 may include a communication interface 1840, which typically controls and manages user input and system output. The communication interface may perform or facilitate the receiving and / or transmitting of wired or wireless communications using wired and / or wireless transceivers, including utilizing audio jacks / plugs, microphone jacks / plugs, Universal Serial Bus (USB) ports / plugs, Apple... ™ Lightning ™ Ports / plugs, Ethernet ports / plugs, fiber optic ports / plugs, dedicated wired ports / plugs, 3G, 4G, 5G and / or other cellular data network wireless signal transmission, Bluetooth ™Wireless signal transmission, Bluetooth ™ Low-power (BLE) wireless signal transmission, IBEACON ™ Wireless signal transmission, including radio frequency identification (RFID) wireless signal transmission, near field communication (NFC) wireless signal transmission, dedicated short range communication (DSRC) wireless signal transmission, 802.11 Wi-Fi wireless signal transmission, wireless local area network (WLAN) signal transmission, visible light communication (VLC), microwave access global interoperability (WiMAX), infrared (IR) wireless signal transmission, public switched telephone network (PSTN) signal transmission, integrated services digital network (ISDN) signal transmission, ad hoc network signal transmission, radio wave signal transmission, microwave signal transmission, infrared signal transmission, visible light signal transmission, ultraviolet light signal transmission, wireless signal transmission along the electromagnetic spectrum, or some combination thereof. The communication interface 1840 may also include one or more Global Navigation Satellite System (GNSS) receivers or transceivers for determining the location of the computing system 1800 based on one or more signals received from one or more satellites associated with one or more GNSS systems. GNSS systems include, but are not limited to, the U.S. Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System (BDS), and Europe's Galileo GNSS. There are no limitations on operation on any particular hardware configuration, and therefore the underlying features here can be easily replaced to obtain improved hardware or firmware configurations as they are developed.

[0170] Storage device 1830 may be a non-volatile and / or non-transitory and / or computer-readable storage device, and may be a hard disk or other type of computer-readable medium capable of storing data accessible by a computer, such as magnetic tape, flash memory cards, solid-state storage devices, digital versatile discs, cartridges, floppy disks, hard disks, magnetic tapes, magnetic stripes, any other magnetic storage media, flash memory, memristor memory, any other solid-state storage, CD-ROM, rewritable CD, digital video disc (DVD), Blu-ray disc (BDD), holographic disc, another optical medium, secure digital (SD) card, micro-secure digital (microSD) card, Memory Stick. ®Cards, smart card chips, EMV chips, Subscriber Identity Module (SIM) cards, mini / micro / nano / micro SIM cards, another integrated circuit (IC) chip / card, random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash EPROM, cache memory (e.g., level 1 (L1) cache, level 2 (L2) cache, level 3 (L3) cache, level 4 (L4) cache, level 5 (L5) cache or other (L#) cache), resistive random access memory (RRAM / ReRAM), phase change memory (PCM), spin-transfer torque RAM (STT-RAM), another memory chip or cassette and / or combinations thereof.

[0171] Storage device 1830 may include software services, servers, services, etc., which enable the system to perform functions when the code defining such software is executed by processor 1810. In some aspects, hardware services that perform specific functions may include software components stored in a computer-readable medium connected to necessary hardware components, such as processor 1810, connection 1805, output device 1835, etc., to perform functions. The term "computer-readable medium" includes, but is not limited to, portable or non-portable storage devices, optical storage devices, and various other media capable of storing, containing, or carrying instructions and / or data. Computer-readable media may include non-transitory media in which data can be stored and which does not include carrier waves and / or transient electronic signals propagated wirelessly or via a wired connection. Examples of non-transitory media may include, but are not limited to, magnetic disks or magnetic tapes, optical storage media (such as compact discs (CDs) or digital versatile discs (DVDs)), flash memory, memory, or memory devices. Computer-readable media may store code and / or machine-executable instructions thereon, which may represent procedures, functions, subroutines, programs, routines, subroutines, modules, software packages, classes, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or hardware circuitry by passing and / or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc., may be passed, forwarded, or transmitted via any suitable means, including memory sharing, message passing, token passing, network transmission, etc.

[0172] Specific details have been provided in the foregoing description to offer a thorough understanding of the aspects and examples presented herein, but those skilled in the art will recognize that this application is not limited thereto. Therefore, although illustrative aspects of this application have been described in detail herein, it is to be understood that the inventive concepts may be embodied and employed in various other ways, and the appended claims are not intended to be construed as including these variations unless limited by prior art. The various features and aspects of the applications described above may be used individually or in combination. Furthermore, without departing from the broader scope of the specification, aspects may be utilized in any number of environments and applications beyond those described herein. Therefore, the specification and drawings should be considered illustrative rather than restrictive. For illustrative purposes, the methods are described in a particular order. It should be understood that, in alternative aspects, the methods may be performed in a different order than described.

[0173] For clarity, in some instances, this technology may be presented as comprising various functional blocks, which include devices, device components, steps, or routines embodied in a method, either in software or a combination of hardware and software. Additional components may be used in addition to those shown in the figures and / or described herein. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form to avoid obscuring these aspects in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail to avoid obscuring the aspects.

[0174] Furthermore, those skilled in the art will understand that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various exemplary components, blocks, modules, circuits, and steps have been described above in general terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of this disclosure.

[0175] Various aspects described above can be presented as processes or methods, depicted as flowcharts, diagrams, data flow diagrams, structure diagrams, or block diagrams. Although flowcharts can describe operations as sequential processes, many operations within an operation can be executed in parallel or concurrently. Furthermore, the order of operations can be rearranged. A process terminates when its operations are completed, but a process may have additional steps not included in the diagrams. A process can correspond to a method, function, procedure, subroutine, subroutine, etc. When a process corresponds to a function, the termination of the process can correspond to the function returning to the calling function or the main function.

[0176] The processes and methods described in the examples above can be implemented using stored computer-executable instructions or computer-executable instructions otherwise available from a computer-readable medium. Such instructions may include, for example, instructions and data that configure, or otherwise configure, a general-purpose computer, special-purpose computer, or processing device to perform a function or group of functions. The portion may be accessible via a network of the computer resources used. The computer-executable instructions may be, for example, binary, intermediate format instructions such as assembly language, firmware, or source code. Examples of computer-readable media that can be used to store the instructions, the information used, and / or information created during the methods according to the described examples include disks or optical discs, flash memory, USB devices with non-volatile memory, networked storage devices, etc.

[0177] In some respects, computer-readable storage devices, media, and memories may include cables or wireless signals containing bit streams, etc. However, when referred to, non-transitory computer-readable storage media explicitly exclude media such as energy, carrier signals, electromagnetic waves, and the signals themselves.

[0178] Those skilled in the art will understand that information and signals can be represented using any of a variety of different techniques and arts. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may, in some cases, be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or light particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0179] The various exemplary logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein can be implemented or executed using hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof, and can take any form factor of various form factors. When implemented in software, firmware, middleware, or microcode, program code or code segments (e.g., computer program products) for performing necessary tasks can be stored in a computer-readable or machine-readable medium. A processor can perform the necessary tasks. Examples of form factors include: laptop computers, smartphones, mobile phones, tablet devices, or other small form factor personal computers, personal digital assistants, rack-mounted devices, self-contained devices, etc. The functionality described herein can also be embodied in peripheral devices or interlocking cards. By further example, such functionality can also be implemented on circuit boards in different chips or different processes running on a single device.

[0180] Instructions, media for delivering such instructions, computing resources for executing them, and other structures for supporting such computing resources are example components for providing the functionality described in this disclosure.

[0181] The techniques described herein can also be implemented in electronic hardware, computer software, firmware, or any combination thereof. Such techniques can be implemented in any of a variety of devices, such as general-purpose computers, wireless communication devices (mobile phones), or integrated circuit devices with multiple uses, including applications in wireless communication devices (mobile phones) and other devices. Any feature described as a module or component can be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. If implemented in software, the techniques can be implemented at least in part by a computer-readable data storage medium comprising program code including instructions that, when executed, perform one or more of the methods, algorithms, and / or operations described above. The computer-readable data storage medium can form part of a computer program product, which may include packaging materials. The computer-readable medium may include memory or data storage media, such as random access memory (RAM) (such as synchronous dynamic random access memory (SDRAM)), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic or optical data storage media, etc. Additionally or alternatively, the technology may be implemented at least in part by a computer-readable communication medium that carries or conveys program code in the form of instructions or data structures that can be accessed, read and / or executed by a computer, such as propagated signals or waves.

[0182] The program code can be executed by a processor, which may include one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Such processors can be configured to perform any of the techniques described in this disclosure. A general-purpose processor may be a microprocessor; however, in alternatives, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. Therefore, as used herein, the term "processor" may refer to any of the foregoing structures, any combination of the foregoing structures, or any other structure or means suitable for implementing the techniques described herein.

[0183] Those skilled in the art will appreciate that the less than ("<") and greater than (">") symbols or terms used herein can be represented by less than or equal to ("<") respectively. ") and greater than or equal to (" The symbol '(')' is used to replace the existing description without deviating from its scope.

[0184] When a component is described as being “configured” to perform certain operations, such configuration can be achieved, for example, by designing electronic circuits or other hardware to perform the operations, by programming programmable electronic circuits (e.g., microprocessors or other suitable electronic circuits) to perform the operations, or any combination thereof.

[0185] The phrase “coupled to” or “communicatively coupled to” means that any component is physically connected directly or indirectly to another component, and / or that any component is in communication with another component directly or indirectly (e.g., connected to that other component via a wired or wireless connection and / or other suitable communication interface).

[0186] Claim language or other languages ​​that state "at least one of" and / or "one or more of" in a set indicate that one member of the set or multiple members of the set (in any combination) satisfy the claim. For example, claim language stating "at least one of A and B" or "at least one of A or B" means A, B, or A and B. In another example, claim language stating "at least one of A, B, and C" or "at least one of A, B, or C" means A, B, C, or A and B, or A and C, or B and C, A and B and C, or any repetition is information or data (e.g., A and A, B and B, C and C, A and A and B, etc.), or any other ordering, repetition, or combination of A, B, and C. The language "at least one of" and / or "one or more of" in a set does not limit the set to the items listed in the set. For example, the language of a claim stating "at least one of A and B" or "at least one of A or B" may refer to A, B, or A and B, and may additionally include items not listed in the set of A and B. The phrases "at least one" and "one or more" are used interchangeably herein.

[0187] Claims using phrases such as "at least one processor, the at least one processor being configured to," "at least one processor being configured to," "one or more processors, the one or more processors being configured to," or "one or more processors being configured to," or other languages, indicate that one or more processors (in any combination) are capable of performing associated operations. For example, a claim using the phrase "at least one processor, the at least one processor being configured to: X, Y, and Z" means that a single processor can be used to perform operations X, Y, and Z; or that multiple processors are each assigned a specific subset of tasks to perform operations X, Y, and Z, such that the multiple processors together perform X, Y, and Z; or that a group of multiple processors work together to perform operations X, Y, and Z. In another example, a claim using the phrase "at least one processor, the at least one processor being configured to: X, Y, and Z" could mean that any single processor can perform only at least one subset of operations X, Y, and Z.

[0188] When referring to one or more elements that perform functions (e.g., steps of a method), one element may perform all functions, or more than one element may jointly perform these functions. When more than one element jointly performs these functions, each function does not need to be performed by every single element (e.g., different functions may be performed by different elements), and / or each function does not need to be performed by only one element as a whole (e.g., different elements may perform different sub-functions of a function). Similarly, when referring to one or more elements configured to cause another element (e.g., a device) to perform functions, one element may be configured to cause another element to perform all functions, or more than one element may be jointly configured to cause another element to perform these functions.

[0189] When referring to an entity that performs or is configured to perform functions (e.g., steps of a method) (e.g., any entity or device described herein), the entity may be configured to cause one or more elements (individually or collectively) to perform those functions. One or more components of the entity may include at least one memory, at least one processor, at least one communication interface, another component configured to perform one or more of those functions, and / or any combination thereof. When referring to an entity that performs functions, the entity may be configured to cause one component to perform all functions, or to cause more than one component to perform those functions collectively. When the entity is configured to cause more than one component to perform those functions collectively, each function does not need to be performed by every single component (e.g., different functions may be performed by different components), and / or each function does not need to be performed by only one component as a whole (e.g., different components may perform different sub-functions of a function).

[0190] The exemplary aspects of this disclosure include: Aspect 1. A method of wireless communication performed at a passive network device, the method comprising: receiving an orthogonal frequency division multiplexing (OFDM) signal from a network device by the passive network device; and transmitting a backscattered signal by the passive network device based on the OFDM signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

[0191] Aspect 2. The method according to aspect 1, wherein the backscattered signal includes a preamble and a payload.

[0192] Aspect 3. The method according to aspect 2, wherein the preamble indicates the start of the backscattered sample relative to the OFDM symbol boundary within the OFDM signal.

[0193] Aspect 4. The method according to any one of Aspects 2 or 3, wherein the backscattered signal further comprises a continuous square wave (CSW) having a time-varying frequency.

[0194] Aspect 5. The method according to aspect 4, wherein the continuous square wave having the time-varying frequency generates multiple frequency shifts in the demodulation reference signal (DMRS) subcarrier of the OFDM signal.

[0195] Aspect 6. The method according to any one of Aspect 4 or 5, wherein the frequency of the continuous square wave can be configured depending on at least one of the tag data rate or the tag signal bandwidth.

[0196] Aspect 7. The method according to any one of Aspects 1 to 6, wherein the demodulation reference signal (DMRS) subcarrier of the OFDM signal is mapped in a plurality of segments.

[0197] Aspect 8. The method according to aspect 7, wherein one or more zero-power (ZP) subcarriers are located between corresponding segment pairs of the plurality of segments from the DMRS subcarriers.

[0198] Aspect 9. The method according to aspect 8, wherein each of the plurality of segments comprises the same base sequence.

[0199] Aspect 10. The method according to any one of Aspects 8 or 9, wherein each of the plurality of segments comprises a sequence generated by applying phase randomization to a base sequence.

[0200] Aspect 11. The method according to any one of Aspects 1 to 10, the method further comprising modulating a portion of the OFDM symbol of the OFDM signal by the passive network device.

[0201] Aspect 12. The method according to aspect 11, wherein the length of said portion of said OFDM symbol can be configured depending on the residual timing error at said passive network device.

[0202] Aspect 13. The method according to any one of Aspects 1 to 12, wherein the OFDM signal is a single tone and includes a cyclic prefix (CP).

[0203] Aspect 14. The method according to any one of Aspects 1 to 13, wherein the passive network device is an Ambient Internet of Things (AIoT) device.

[0204] Aspect 15. The method according to any one of Aspects 1 to 14, wherein the network device is a base station or a user equipment (UE).

[0205] Aspect 16. A passive network device for wireless communication, the passive network device comprising: at least one memory; and at least one processor coupled to the at least one memory and configured to: receive an orthogonal frequency division multiplexing (OFDM) signal from the network device; and induce the transmission of a backscattered signal based on the OFDM signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

[0206] Aspect 17. The passive network device according to aspect 16, wherein the backscatter signal includes a preamble and a payload.

[0207] Aspect 18. The passive network device according to aspect 17, wherein the preamble indicates the start of the backscattered sample relative to the OFDM symbol boundary within the OFDM signal.

[0208] Aspect 19. The passive network device according to any one of Aspects 17 or 18, wherein the backscatter signal further comprises a continuous square wave (CSW) having a time-varying frequency.

[0209] Aspect 20. The passive network device according to aspect 19, wherein the continuous square wave having the time-varying frequency generates multiple frequency shifts in the demodulation reference signal (DMRS) subcarrier of the OFDM signal.

[0210] Aspect 21. The passive network device according to any one of Aspects 19 or 20, wherein the frequency of the continuous square wave can be configured depending on at least one of the tag data rate or the tag signal bandwidth.

[0211] Aspect 22. The passive network device according to any one of Aspects 16 to 21, wherein the demodulation reference signal (DMRS) subcarrier of the OFDM signal is mapped in a plurality of segments.

[0212] Aspect 23. The method according to aspect 22, wherein one or more zero-power (ZP) subcarriers are located between corresponding segment pairs of the plurality of segments from the DMRS subcarriers.

[0213] Aspect 24. The method according to aspect 23, wherein each of the plurality of segments comprises the same base sequence.

[0214] Aspect 25. The method according to any one of Aspects 23 or 24, wherein each of the plurality of segments comprises a sequence generated by applying phase randomization to a base sequence.

[0215] Aspect 26. The passive network device according to any one of Aspects 16 to 25, wherein the at least one processor is configured as part of an OFDM symbol for modulating the OFDM signal.

[0216] Aspect 27. The passive network device according to aspect 26, wherein the length of said portion of said OFDM symbol can be configured depending on the residual timing error at said passive network device.

[0217] Aspect 28. The passive network device according to any one of Aspects 16 to 27, wherein the OFDM signal is a single tone and includes a cyclic prefix (CP).

[0218] Aspect 29. The passive network device according to any one of Aspects 16 to 28, wherein the passive network device is an Ambient Internet of Things (AIoT) device.

[0219] Aspect 30. The passive network device according to any one of Aspects 16 to 29, wherein the network device is a base station or a user equipment (UE).

[0220] Aspect 31. A non-transitory computer-readable storage medium comprising instructions stored thereon, the instructions causing the at least one processor, when executed by at least one processor, to perform any one of aspects 16 to 30.

[0221] Aspect 32. An apparatus for wireless communication, the apparatus comprising one or more components for performing operations according to any one of aspects 16 to 30.

[0222] Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be consistent with the full scope of language claims, wherein an element referred to in the singular is not intended to mean “one and only one”, but rather “one or more” unless specifically stated so.

Claims

1. A method for wireless communication performed at a passive network device, the method comprising: The passive network device receives orthogonal frequency division multiplexing (OFDM) signals from the network device. as well as The passive network device transmits a backscattered signal based on the OFDM signal, the backscattered signal including the frequency of the OFDM signal shifted to a non-overlapping frequency.

2. The method according to claim 1, wherein the backscatter signal comprises a preamble and a payload.

3. The method of claim 2, wherein the preamble indicates the start of the backscattered sample relative to the OFDM symbol boundary within the OFDM signal.

4. The method according to claim 2, wherein the backscattered signal further comprises a continuous square wave having a time-varying frequency.

5. The method of claim 4, wherein the continuous square wave having the time-varying frequency generates multiple frequency shifts in the demodulation reference signal (DMRS) subcarrier of the OFDM signal.

6. The method of claim 4, wherein the frequency of the continuous square wave can be configured depending on at least one of the tag data rate or the tag signal bandwidth.

7. The method of claim 1, wherein the demodulation reference signal (DMRS) subcarrier of the OFDM signal is mapped in multiple segments.

8. The method of claim 7, wherein one or more zero-power (ZP) subcarriers are located between corresponding segment pairs of the plurality of segments from the DMRS subcarriers.

9. The method of claim 8, wherein each of the plurality of segments comprises the same base sequence.

10. The method of claim 8, wherein each of the plurality of segments comprises a sequence generated by applying phase randomization to a base sequence.

11. The method of claim 1, further comprising modulating a portion of the OFDM symbol of the OFDM signal by the passive network device.

12. The method of claim 11, wherein the length of said portion of said OFDM symbol can be configured depending on the residual timing error at the passive network device.

13. The method of claim 1, wherein the OFDM signal is a single tone and includes a cyclic prefix (CP).

14. The method of claim 1, wherein the passive network device is an Ambient Internet of Things (AIoT) device.

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

16. A passive network device for wireless communication, the passive network device comprising: At least one memory; and At least one processor, the at least one processor being coupled to the at least one memory and being configured to: Receive orthogonal frequency division multiplexing (OFDM) signals from network devices; and The transmission of a backscattered signal is caused based on the OFDM signal, the backscattered signal including a frequency of the OFDM signal shifted to a non-overlapping frequency.

17. The passive network device of claim 16, wherein the backscatter signal comprises a preamble and a payload.

18. The passive network device of claim 17, wherein the preamble indicates the start of the backscattered sample relative to the OFDM symbol boundary within the OFDM signal.

19. The passive network device of claim 17, wherein the backscattered signal further comprises a continuous square wave having a time-varying frequency.

20. The passive network device of claim 19, wherein the continuous square wave having the time-varying frequency generates multiple frequency shifts in the demodulation reference signal (DMRS) subcarrier of the OFDM signal.

21. The passive network device of claim 19, wherein the frequency of the continuous square wave can be configured depending on at least one of the tag data rate or the tag signal bandwidth.

22. The passive network device of claim 16, wherein the demodulation reference signal (DMRS) subcarrier of the OFDM signal is mapped in a plurality of segments.

23. The method of claim 22, wherein one or more zero-power (ZP) subcarriers are located between corresponding segment pairs of the plurality of segments from the DMRS subcarriers.

24. The method of claim 23, wherein each of the plurality of segments comprises the same base sequence.

25. The method of claim 23, wherein each of the plurality of segments comprises a sequence generated by applying phase randomization to a base sequence.

26. The passive network device of claim 16, wherein the at least one processor is configured to be part of an OFDM symbol for modulating the OFDM signal.

27. The passive network device of claim 26, wherein the length of said portion of said OFDM symbol can be configured depending on the residual timing error at said passive network device.

28. The passive network device of claim 16, wherein the OFDM signal is a single tone and includes a cyclic prefix (CP).

29. The passive network device of claim 16, wherein the passive network device is an environmental Internet of Things (AIoT) device.

30. The passive network device of claim 16, wherein the network device is a base station or a user equipment (UE).

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