Carrier transmit power control and periodic energy harvesting for backscatter devices

Abstract

Techniques for carrier transmission and energy harvesting in passive or semi-passive backscatter devices are described. An apparatus may be configured to transmit information indicating a power preference of the apparatus to a first network node; receiving a radio frequency (RF) signal from the first network node, wherein the RF signal is based on the information; and transmitting data to one or more of the first network node or the second network node based on backscatter modulation of the RF signal.

Description

Technical Field

[0001] This disclosure relates generally to wireless communication systems, and more specifically to carrier power control techniques for energy harvesting and backscatter communication. Background Technology

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunications services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems employ multiple access technologies that enable communication with multiple users by sharing available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems.

[0003] These multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different wireless devices to communicate at the city, country, region, and even global levels. An example telecommunications standard is 5G New Radio (NR). 5G NR is part of the Continuous Evolution of Mobile Broadband (CWB) program issued by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Some aspects of 5G NR are based on the 4G Long Term Evolution (LTE) standard.

[0004] The wireless communication system can also be configured to communicate with one or more backscattering devices. A backscattering device can be a radio frequency (RF) energy harvesting device. Generally, an RF energy harvesting device is configured to capture ambient RF signals such as Wi-Fi, cellular, or radio signals and convert them into usable power, which can be used to perform one or more functions of the RF energy harvesting device.

[0005] As the demand for mobile broadband access continues to increase, research and development continue to improve wireless communication technologies, not only to meet the growing demand for mobile broadband access, but also to improve and enhance the user experience of mobile communications. Summary of the Invention

[0006] To provide a basic understanding of one or more aspects of this disclosure, an overview of such aspects is given below. This overview is not a comprehensive summary of all intended features of this disclosure, and is neither intended to identify key or essential elements of all aspects of this disclosure, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present some concepts of one or more aspects of this disclosure in a simplified form as a prelude to the more detailed description given later. While some examples may be discussed as including certain aspects or features, all examples discussed may include any features discussed. Unless explicitly described, no single aspect or feature is necessary to achieve the technical effects or solutions discussed herein.

[0007] Various aspects of the technology disclosed herein relate to power control for backscattering devices. A backscattering device can be an RF energy harvesting device configured to capture ambient RF signals such as Wi-Fi, cellular, or radio signals and convert them into usable power, which can be used to perform one or more functions, including transmitting data using backscatter modulation of an incoming RF signal. According to the technology disclosed herein, the backscattering device can transmit information indicating power preferences to a reader (e.g., a network node). The reader can be user equipment (UE), such as a mobile phone, network base station, or another RF transmitter. The reader can use this information to perform open-loop or closed-loop power control on the backscattering device by adjusting the power of the RF signal transmitted to the backscattering device.

[0008] In examples of open-loop power control, the information indicating power preference may be information that a reader can use to estimate the amount of power available for energy harvesting at the backscattering device. In some examples, this information may include modulation type, impedance state, and associated reflection coefficient. In other examples, this information may include the power ratio difference between the power available for energy harvesting and the power available for backscattering modulation. The reader may measure the received backscattered power and then estimate the power available for energy harvesting based on this information. If the estimated power available for energy harvesting differs from the target power, the reader may increase or decrease the power of subsequent RF signals transmitted to the backscattering device.

[0009] In an example of closed-loop power control, the reader may receive information from the backscattering device that directly indicates whether to increase or decrease the power of the RF signal. In other examples, the information transmitted from the backscattering device to the reader may include information indicating the periodicity and / or timing window of the RF signal to avoid putting the backscattering device into a sleep state (e.g., a cold start state), which could lead to an undesirable situation where it takes a long time to start up.

[0010] The technology disclosed herein allows one or more readers to determine an optimal amount of power for an ambient RF signal used by a backscattering device to harvest energy and transmit data via backscatter modulation. Furthermore, the technology disclosed herein allows readers to determine an optimal periodicity for transmitting RF signals to the backscattering device, thereby reducing the likelihood of the backscattering device entering a cold start state. For certain use cases, preventing the backscattering device from entering a cold start state can improve data transmission speed and / or data transmission reliability.

[0011] In one example, this disclosure describes an apparatus for passive wireless communication, the apparatus including one or more processors and a memory accessible by the one or more processors, wherein the one or more processors are configured to: transmit information indicating the power preference of the apparatus to a first network node; receive a radio frequency (RF) signal from the first network node, wherein the RF signal is based on the information; and transmit data to one or more of the first network node or a second network node based on backscatter modulation of the RF signal.

[0012] In another example, this disclosure describes a network node for passive wireless communication, the network node including one or more processors and a memory accessible by the one or more processors, wherein the one or more processors are configured to: receive information from a backscattering device indicating the power preference of the backscattering device; transmit an RF signal to the backscattering device, wherein the RF signal is based on the information; and receive data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0013] In another example, this disclosure describes a method for passive wireless communication by a backscattering device, the method comprising: transmitting to a first network node information indicating the power preference of the backscattering device; receiving an RF signal from the first network node, wherein the RF signal is based on the information; and transmitting data to one or more of the first network node or a second network node based on backscattering modulation of the RF signal.

[0014] In another example, this disclosure describes a method for passive wireless communication, the method comprising: receiving information from a backscattering device indicating the power preference of the backscattering device; transmitting an RF signal to the backscattering device, wherein the RF signal is based on the information; and receiving data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0015] In another example, this disclosure describes an apparatus for passive wireless communication, the apparatus comprising: means for transmitting to a first network node information indicating a power preference of a backscattering device; means for receiving an RF signal from the first network node, wherein the RF signal is based on the information; and means for transmitting data to one or more of the first network node or a second network node based on backscattering modulation of the RF signal.

[0016] In another example, this disclosure describes an apparatus for passive wireless communication, the apparatus comprising: means for receiving information from a backscattering device indicating the power preference of the backscattering device; means for transmitting an RF signal to the backscattering device, wherein the RF signal is based on the information; and means for receiving data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0017] In another example, this disclosure describes a non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors to: transmit information indicating the power preference of the device to a first network node; receive an RF signal from the first network node, wherein the RF signal is based on the information; and transmit data to one or more of the first network node or a second network node based on backscatter modulation of the RF signal.

[0018] In another example, this disclosure describes a non-transitory computer-readable storage medium storing instructions that, when executed, cause one or more processors to: receive information from a backscattering device indicating the power preference of the backscattering device; transmit an RF signal to the backscattering device, wherein the RF signal is based on the information; and receive data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0019] A more comprehensive understanding of these and other aspects of the technology discussed herein will be gained after reading the following detailed description. Other aspects and features will become apparent to those skilled in the art after reading the description of specific examples below in conjunction with the accompanying drawings. While the following description may discuss various advantages and features with respect to certain examples, embodiments, and drawings, all examples may include one or more of the advantageous features discussed herein. In other words, although this description may discuss one or more examples as having certain advantageous features, one or more such features may also be used according to various other examples discussed herein. Similarly, while this description may discuss certain examples as devices, systems, or methods, it should be understood that such examples of the teachings of this disclosure can be implemented in various devices, systems, and methods. Attached Figure Description

[0020] Figure 1 Examples of wireless communication systems 100 supporting carrier transmit power control and periodic energy harvesting for backscatter devices according to one or more aspects of this disclosure are illustrated.

[0021] Figure 2 Examples of full-duplex communication between a reader and a backscattering device according to one or more aspects of this disclosure are illustrated.

[0022] Figure 3 Examples of half-duplex communication between multiple readers and a backscattering device according to one or more aspects of this disclosure are illustrated.

[0023] Figure 4 This is a block diagram illustrating example communication between a reader and a backscattering device according to one or more aspects of this disclosure.

[0024] Figure 5 This is a block diagram of an example backscattering device according to one or more aspects of this disclosure.

[0025] Figure 6 This is a block diagram illustrating an example technique for power control in a backscattering device according to one or more aspects of this disclosure.

[0026] Figure 7 It is a timing diagram for transmitting RF signals for energy harvesting according to one or more aspects of this disclosure.

[0027] Figure 8 This is a call flowchart illustrating an example of carrier transmit power control according to one or more aspects of this disclosure.

[0028] Figure 9 This is a call flowchart illustrating another example of carrier transmit power control according to one or more aspects of this disclosure.

[0029] Figure 10 This is a block diagram illustrating examples of specific hardware implementations for network nodes according to some aspects of this disclosure.

[0030] Figure 11 This is a flowchart illustrating another example of a process for power control in a backscattering device according to some aspects of this disclosure.

[0031] Figure 12 This is a flowchart illustrating another example of a process for power control in a backscattering device according to some aspects of this disclosure. Detailed Implementation

[0032] Wireless communication systems may include multiple communication devices, such as user equipment (UEs) and base stations (e.g., network entities), which provide wireless communication services to UEs. For example, such base stations may be next-generation NodeBs or gigabit NodeBs (either of which may be referred to as gNBs) supporting multiple radio access technologies (RATs), including fourth-generation (4G) systems (such as Long Term Evolution (LTE) systems) and fifth-generation (5G) systems (which may be referred to as New Radio (NR) systems). Some UEs may support the transmission, reception, and reporting of reference signals.

[0033] The UE and network entity of a wireless communication system can be configured to communicate with one or more backscattering devices. A backscattering device can be an RF energy harvesting device. Generally, an RF energy harvesting device is configured to capture ambient RF signals such as Wi-Fi, cellular, or radio signals and convert them into usable power, which can be used to perform one or more functions of the RF energy harvesting device. Some example RF energy harvesting devices can operate over a wide RF frequency range. The efficiency of these devices depends on various factors, such as antenna design and rectifier efficiency. The amount of energy harvested by an RF energy harvesting device is typically low and depends on the strength of the RF signal and the proximity of the device to the RF source (e.g., the UE or network entity).

[0034] RF energy harvesting devices are commonly used in applications such as wireless sensor networks, Internet of Things (IoT) devices, and other low-power electronic devices. These devices eliminate the need for traditional batteries or power sources, thereby reducing maintenance costs and improving the sustainability of these systems. RF energy harvesting devices can also supplement the power supply of other electronic devices, extending their battery life or reducing the need for frequent charging.

[0035] The basic architecture of an RF energy harvesting device may include an antenna, a rectifier, a microcontroller, and sensors. The antenna is designed to capture RF signals from the environment and convert those signals into an AC voltage signal. The rectifier is used to convert that AC signal into a DC voltage signal, which can be used to power the microcontroller and sensors. The microcontroller can read data from the sensors and control the antenna's reflection coefficient to perform backscatter modulation of the incoming RF signal, thereby transmitting data to one or more readers.

[0036] The backscatter modulation process may involve two devices: a reader and a backscattering device. The reader transmits a continuous wave (CW) signal (e.g., an RF signal) to the backscattering device at a specific frequency. The backscattering device absorbs some of the energy of this signal and reflects the remaining energy back to the reader. By modulating the amplitude or frequency of the reflected signal, the backscattering device can send information (e.g., data) to the reader.

[0037] In the context of a wireless communication system, a reader may be one or more UEs and / or network entities (e.g., gNB). This disclosure generally refers to a reader as a network node, where the term "network node" may cover any device configured to receive backscattered communications from a backscattering device.

[0038] Recently, ambient IoT (e.g., passive IoT) technologies have garnered attention within 3GPP. Some example ambient IoT technologies aim to create low-complexity, low-power devices, with complexity and power consumption several orders of magnitude lower than existing technologies such as enhanced machine-type communication (eMTC) and / or narrowband IoT (NB-IoT). Ambient IoT devices (e.g., backscatter devices) are generally categorized into two types. Type A ambient IoT devices are those without energy storage capabilities (e.g., no battery) and rely entirely on the availability of an external power source (e.g., RF signal / CW). Type B ambient IoT devices have limited energy storage (e.g., supercapacity or conventional capacity) that does not require manual replacement or recharging.

[0039] Currently, power control of backscattering devices (e.g., controlling the power of ambient RF signals) is challenging because the reader lacks any mechanism to determine the amount of power collected by the backscattering device. In some examples, the backscattering device may operate based on a minimum RF input power requirement for energy harvesting (e.g., -20 dBm for a battery-less device). However, excessive input power can overcharge the rectifier and lead to energy waste. Therefore, it is preferable that the power collected by the backscattering device provides the minimum level of power required to harvest power from the RF signal from the reader and to modulate the signal backscattered back to the reader.

[0040] For backscatter communication, higher data rates can be achieved by switching antenna impedance at faster frequencies. However, faster antenna switching frequencies can increase power consumption. Therefore, the maximum data rate is often determined by the power collected, especially for battery-less devices where power comes directly from the incoming RF signal.

[0041] Therefore, information indicating the power collected at a passive backscattering device can be beneficial for more efficient scheduling of backscattering communications with the reader. Furthermore, information indicating the power collected at a passive backscattering device can also enable the reader to perform power control on RF signals (e.g., CW) to support more efficient energy harvesting.

[0042] Another issue with some example backscatter devices relates to the initial power-on duration and transmission periodicity of ambient RF signals (e.g., CW). For backscatter devices with limited energy storage, when the backscatter device loses power due to an unavailable power source and cannot provide sufficient power to charge the backscatter device's microcontroller and / or storage elements, the available voltage on the backscatter device may drop below a critical level, causing the backscatter device's circuitry to enter a sleep state (e.g., a cold start state).

[0043] To prevent entering a cold start state (where the initial charging time can be long, for example, hundreds of milliseconds depending on the connection capacity), it is preferable to periodically send RF signals to the backscattering device to keep it active. However, if the backscattering device is in good power condition or has no data to send, periodic RF signal transmission may result in wasted energy. Periodic RF signal transmission may also cause unnecessary interference to communication signals.

[0044] This disclosure describes techniques for addressing one or more of the aforementioned problems with passive backscattering devices. Specifically, this disclosure describes various signaling techniques that allow one or more readers to determine an optimal amount of power for an ambient RF signal used by the backscattering device to harvest energy and transmit data via backscatter modulation. Furthermore, the techniques of this disclosure allow readers to determine an optimal periodicity and / or timing window for transmitting RF signals to the backscattering device, thereby reducing the likelihood of the backscattering device entering a cold start state. For certain use cases, preventing the backscattering device from entering a cold start state can improve data transmission speed and / or data transmission reliability.

[0045] Figure 1 Examples of wireless communication systems 100 supporting carrier transmit power control and periodic energy harvesting for backscattered devices, according to one or more aspects of this disclosure, are illustrated. Wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some aspects, wireless communication system 100 may be a Long Term Evolution (LTE) network, an Advanced LTE (LTE-A) network, an LTE-A Pro network, a New Radio (NR) network, or a network operating according to other systems and radio technologies, including future systems and radio technologies not explicitly mentioned herein.

[0046] Network entity 105 may be distributed across a geographical area to form wireless communication system 100 and may include devices in different forms or with different capabilities. In various examples, network entity 105 may be referred to as a network element, network node, base station, gNB, mobility element, radio access network (RAN) node, or network equipment, among other names. In some aspects, network entity 105 and UE 115 may wirelessly communicate via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, network entity 105 may support a coverage area 110 (e.g., a geographical coverage area) within which UE 115 and network entity 105 may establish one or more communication links 125. Coverage area 110 may be an example of a geographical area within which network entity 105 and UE 115 may support signal communication according to one or more radio access technologies (RATs).

[0047] UE 115 can be distributed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 can be stationary, mobile, or both at different times. In some examples, one or more UEs among UE 115 can be devices with energy harvesting (EH) capabilities, such as passive or semi-passive backscatter devices. Reference will be made below. Figure 2 and Figure 3 Examples of backscattering devices are discussed in more detail. UE 115 can be a device in different forms or with different capabilities. Figure 1 Examples of UE 115 are illustrated herein. The UE 115 described herein may be able to support communication with various types of devices, such as other UE 115s or network entities 105, such as Figure 1 As shown.

[0048] As described herein, a node (which may be referred to as a node, network node, network entity, or wireless node) may include, be, or be included in (e.g., 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 processing reference signals during DRX inactivity periods. For example, a network node may be a UE. Alternatively, a network node may be a base station or a network entity. Alternatively, 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 other aspects of this example, the first network node, the second network node, and the third network node may differ 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 wider example of a narrower example may be interpreted in reverse, but in a broad, open-ended manner. In the above example where the UE is configured to receive information from the base station and the first network node is configured to receive information from the second network node, the first network node may refer to the first UE, the first base station, the first device, the first equipment, the first computing system, the first set of one or more components or the first processing entity, etc., configured to receive information; and the second network node may refer to the second UE, the second base station, the second device, the second equipment, the second computing system, the second set of one or more components or the second processing entity, etc.

[0049] 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.

[0050] In some aspects, network entities 105 may communicate with the core network 130, communicate with each other, or both. For example, network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some aspects, network entities 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via the core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some aspects, network entities 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. The backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof, or may include one or more wired links (e.g., electrical links, fiber optic links), one or more wireless links (e.g., radio links, wireless optical links), etc., or various combinations thereof. The UE 115 may communicate with the core network 130 via communication link 155.

[0051] One or more network entities in network entity 105 described herein may include base station 140 or may be referred to as base station 140 (e.g., transceiver base station, radio base station, NR base station, access point, radio transceiver, Node B, evolved Node B (eNB), next-generation Node B or gigabit Node B (any of which may be referred to as gNB), 5G NB, next-generation eNB (ng-eNB), home Node B, home evolved Node B, or other suitable terms). In some aspects, network entity 105 (e.g., base station 140) may be implemented in a converged (e.g., monolithic, self-contained) base station architecture that may be configured to utilize a protocol stack physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as base station 140).

[0052] In some aspects, network entity 105 may be implemented in a decomposed architecture (e.g., a decomposed base station architecture, a decomposed RAN architecture) that can be configured to utilize protocol stacks physically or logically distributed among two or more network entities 105 (such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN))). For example, network entity 105 may include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near real-time RIC, a non-real-time RIC), a service management and orchestration (SMO) 180 system, or any combination thereof. RU 170 may also be referred to as a radio headend, an intelligent radio headend, a remote radio headend (RRH), a remote radio unit (RRU), or a transmit-receive point (TRP). One or more components of network entity 105 in a decomposed RAN architecture may be co-located, or one or more components of network entity 105 may be located in distributed locations (e.g., separate physical locations). In some aspects, one or more network entities 105 in a decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0053] The functional decomposition among CU 160, DU 165, and RU 170 is flexible and can support different functions depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, or RU 170. For example, a protocol stack functional decomposition can be used between CU 160 and DU 165, allowing CU 160 to support one or more layers of the protocol stack, and DU 165 to support one or more different layers of the protocol stack. In some respects, CU 160 can host higher protocol layer (e.g., Layer 3 (L3), Layer 2 (L2)) functionality and signaling (e.g., Radio Resource Control (RRC), Serving Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)). CU 160 can connect to one or more DU 165 or RU 170, and one or more DU 165 or RU 170 can host lower protocol layers, such as Layer 1 (L1) (e.g., Physical (PHY) layer) or L2 (e.g., Radio Link Control (RLC) layer, Medium Access Control (MAC) layer) functionality and signaling, and each can be at least partially controlled by CU 160. Additionally or alternatively, a protocol stack functional split can be employed between DU 165 and RU 170, such that DU 165 can support one or more layers of the protocol stack, and RU 170 can support one or more different layers of the protocol stack. DU 165 can support one or more different cells (e.g., via one or more RU 170). In some cases, functional decomposition between CU 160 and DU 165, or between DU 165 and RU 170, can be performed within the protocol layer (e.g., some functions of the protocol layer can be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer can be performed by different of CU 160, DU 165, or RU 170). CU 160 can be further functionally decomposed into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 can be connected to one or more DU 165 via midhaul communication link 162 (e.g., F1, F1-c, F1-u), and DU 165 can be connected to one or more RU 170 via fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some respects, the midhaul communication link 162 or the fronthaul communication link 168 may be implemented based on the interfaces (e.g., channels) between the layers of the protocol stack, each layer of which is supported by the corresponding network entity 105 communicating via such communication links.

[0054] In some wireless communication systems (e.g., wireless communication system 100), the infrastructure and spectrum resources for radio access can support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB node 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DU 165s or one or more RU 170s may be partially controlled by one or more CU 160s associated with donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB node 104) via supported access and backhaul links (e.g., backhaul communication link 120). IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a DU 165 of a coupled IAB donor. The IAB-MT may include a separate set of antennas for relaying communication with UE 115, or may share the same antennas (e.g., those of RU 170) for access to IAB node 104 via DU 165 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some aspects, IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of IAB node 104) may be configured to operate according to the techniques described herein.

[0055] In the context of applying the techniques described herein to a decomposed RAN architecture, one or more components of the decomposed RAN architecture may be configured to support the processing of reference signals during DRX inactivity periods as described herein. For example, some operations described as being performed by UE 115 or network entity 105 (e.g., base station 140) may additionally or alternatively be performed by one or more components of the decomposed RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0056] UE 115 may include mobile devices, wireless devices, remote devices, handheld devices, network nodes, or subscriber devices, or any other suitable term, and may be referred to as mobile devices, wireless devices, remote devices, handheld devices, network nodes, or subscriber devices, or any other suitable term, wherein "device" may also be referred to as a cell, station, terminal, or client, etc. UE 115 may also include personal electronic devices, or may be referred to as personal electronic devices, such as cellular phones, personal digital assistants (PDAs), tablet computers, laptop computers, or personal computers. In some aspects, UE 115 may include wireless local loop (WLL) stations, Internet of Things (IoT) devices, Internet of Everything (IoE) devices, or machine-type communication (MTC) devices, or may be referred to as wireless local loop (WLL) stations, Internet of Things (IoT) devices, Internet of Everything (IoE) devices, or machine-type communication (MTC) devices, which may be implemented in various objects such as electrical appliances or vehicles, instruments, etc.

[0057] The UE 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays, as well as network entities 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc. Figure 1 As shown.

[0058] UE 115 and network entity 105 can wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" can refer to a set of RF spectrum resources that define the physical layer structure used to support the communication link 125. For example, a carrier for the communication link 125 may include a portion of the RF spectrum band (e.g., a bandwidth portion (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating carrier operation, user data, or other signaling. The wireless communication system 100 can support communication with UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, UE 115 can be configured to have multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers. Communication between network entity 105 and other devices can refer to communication between these devices and any part of network entity 105 (e.g., entity, sub-entity). For example, the terms “send,” “receive,” or “communicate” when referring to network entity 105 can refer to any part of the RAN’s network entity 105 (e.g., base station 140, CU 160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0059] In some aspects, such as in carrier aggregation configurations, carriers may also have acquisition signaling or control signaling to coordinate the operation of other carriers. Carriers may be associated with frequency channels (e.g., Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute RF Channel Number (EARFCN)) and may be identified according to a channel grating used for discovery by UE 115. Carriers may operate in standalone mode, in which case initial acquisition and connection can be performed by UE 115 via that carrier, or carriers may operate in non-standalone mode, in which case different carriers (e.g., the same or different radio access technologies) are used to anchor the connection.

[0060] The communication link 125 shown in the wireless communication system 100 may include downlink transmission (e.g., forward link transmission) from network entity 105 to UE 115, uplink transmission (e.g., return link transmission) from UE 115 to network entity 105, or both, as well as other transmission configurations. The carrier may carry downlink communication or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink and uplink communication (e.g., in TDD mode).

[0061] A carrier may be associated with a specific bandwidth of the RF spectrum, and in some aspects, the carrier bandwidth may be referred to as the carrier or the “system bandwidth” of the wireless communication system 100. For example, the carrier bandwidth may be one bandwidth in a set of bandwidths for a particular radio access technology (e.g., 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 40 MHz, or 80 MHz). Devices of the wireless communication system 100 (e.g., network entity 105, UE 115, or both) may have hardware configurations that support communication using a specific carrier bandwidth, or may be configured to support communication using one carrier bandwidth in a set of carrier bandwidths. In some aspects, the wireless communication system 100 may include network entity 105 or UE 115 that supports concurrent communication using carriers associated with multiple carrier bandwidths. In some aspects, each served UE 115 may be configured to operate using a portion (e.g., a sub-band, BWP) or all of the carrier bandwidth.

[0062] The signal waveform transmitted via a carrier may include multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform extended OFDM (DFT-S-OFDM)). In a system employing MCM, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and subcarrier spacing may be inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the decoding rate of the modulation scheme, or both), such that a relatively high number of resource elements (e.g., in the transmission duration) and a relatively high-order modulation scheme can correspond to a relatively high communication rate. Wireless communication resources may refer to a combination of RF spectrum resources, temporal resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial resources can increase the data rate or data integrity used for communication with UE 115.

[0063] One or more parameter sets of a carrier can be supported, and the parameter sets may include subcarrier spacing (Δf) and cyclic prefix. A carrier can be divided into one or more BWPs with the same or different parameter sets. In some aspects, the UE 115 can be configured with multiple BWPs. In some aspects, a single BWP for a carrier can be active at a given time, and communication for the UE 115 can be limited to one or more active BWPs.

[0064] The time interval for network entity 105 or UE 115 can be expressed as a multiple of a basic time unit, such as the sampling period T. s =1 / (Δf) max ·N f ) seconds, where Δfmax This can represent the supported subcarrier spacing, while N f The supported Discrete Fourier Transform (DFT) size can be represented. The time interval of the communication resources can be organized according to radio frames, each with a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a System Frame Number (SFN) (e.g., ranging from 0 to 1023).

[0065] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some aspects, a frame may (e.g., in the time domain) be divided into subframes, and each subframe may be further divided into a number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, time slots may be further divided into multiple micro-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., N) symbols. f The duration of a symbol period is associated with a (number) sampling period. The duration of a symbol period can depend on the subcarrier spacing or the operating frequency band.

[0066] A subframe, time slot, micro-time slot, or symbol may be the smallest scheduling unit of the wireless communication system 100 (e.g., in the time domain) and may be referred to as a transmission time interval (TTI). In some aspects, the duration of the TTI (e.g., the number of symbol periods in the TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0067] Physical channels can be multiplexed using various techniques to enable communication using carriers. For example, one or more of Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), or hybrid TDM-FDM techniques can be used to multiplex physical control channels and physical data channels for signaling via downlink carriers. The control region of a physical control channel (e.g., a control resource set (CORESET)) can be defined by a set of symbol periods and can extend across the system bandwidth of a carrier or a subset of that bandwidth. One or more control regions (e.g., CORESETs) can be configured for a set of UEs 115. For example, one or more UEs in UE115 can monitor or search control regions to obtain control information based on one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a concatenated manner. The aggregation level of control channel candidates can refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space set may include: a common search space set configured to transmit control information to multiple UEs 115, and a UE-specific search space set used to transmit control information to a specific UE 115.

[0068] Network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used (e.g., using a carrier) to communicate with network entity 105 and may be associated with an identifier used to distinguish adjacent cells (e.g., Physical Cell Identifier (PCID), Virtual Cell Identifier (VCID), or other identifier). In some aspects, a cell may also refer to a coverage area 110 or a portion of coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors such as the capabilities of network entity 105, the range of such cells may be from smaller areas (e.g., structures, subsets of structures) to larger areas. For example, a cell may be a building, a subset of buildings, or external space between or overlapping coverage areas 110, or may include buildings, subsets of buildings, or external space between or overlapping coverage areas 110.

[0069] Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access to UE 115 that has a service subscription with a network provider supporting the macro cell. In contrast, small cells may be associated with a lower-power network entity 105 (e.g., a lower-power base station 140) and may operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to UE 115 that has a service subscription with a network provider, or restricted access to UE 115 associated with a small cell (e.g., UE 115 in a Closed Subscriber Group (CSG), or UE 115 associated with a user in a home or office). Network entity 105 may support one or more cells and may also use one or more component carriers to support communication via one or more cells.

[0070] In some respects, a carrier can support multiple cells and can be configured with different cells based on different protocol types that can provide access for different types of devices (e.g., MTC, Narrowband IoT (NB-IoT), Enhanced Mobile Broadband (eMBB)).

[0071] In some aspects, network entity 105 (e.g., base station 140, RU 170) may be mobile, and thus provide communication coverage to mobile coverage areas 110. In some aspects, while different coverage areas 110 associated with different technologies may overlap, different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 use the same or different radio access technologies to provide coverage for various coverage areas 110.

[0072] Wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication, or various combinations thereof. For example, wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). UE 115 may be designed to support ultra-reliable, low-latency, or critical functions. Ultra-reliable communication may include private or group communication and may be supported by one or more services, such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritizing services, and such services may be used for public safety or general business applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency may be used interchangeably herein.

[0073] In some aspects, UE 115 may be configured to support direct communication with other UE 115s via device-to-device (D2D) communication link 135 (e.g., according to peer-to-peer (P2P), D2D, or sidelink protocols). In some aspects, one or more UEs 115s performing D2D communication in a group may be within the coverage area 110 of network entity 105 (e.g., base station 140, RU 170), which may support aspects of such D2D communication configured (e.g., scheduled) by network entity 105. In some aspects, one or more UEs 115s in such a group may be outside the coverage area 110 of network entity 105, or may otherwise be unable or not configured to receive transmissions from network entity 105. In some aspects, a group of UEs 115s communicating via D2D communication may support a one-to-many (1:M) system, wherein each UE 115 transmits to every other UE 115 in the group. In some respects, network entity 105 can facilitate the scheduling of resources for D2D communication. In some other examples, D2D communication can be performed between UEs 115 without involving network entity 105.

[0074] In some systems, the D2D communication link 135 may be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some aspects, vehicles may communicate using vehicle-to-vehicle (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles may use signal notifications to communicate information related to traffic conditions, signal control, weather, safety, emergencies, or any other information relevant to the V2X system. In some aspects, vehicles in a V2X system may communicate with roadside infrastructure such as roadside units, or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or with both.

[0075] Core network 130 provides user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. Core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), and may include at least one control plane entity (e.g., a Mobility Management Entity (MME), Access and Mobility Management Function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), or User Plane Function (UPF)) for routing packets or interconnecting to external networks. The control plane entity manages non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by network entity 105 (e.g., base station 140) associated with core network 130. User IP packets can be transferred through user plane entities, which provide IP address allocation and other functions. User plane entities may connect to one or more network operator IP services 150. IP services 150 may include access to the Internet, intranets, IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0076] Wireless communication system 100 can operate using one or more frequency bands in the range of 300 MHz to 300 GHz. Generally, the region from 300 MHz to 3 GHz is referred to as the Ultra High Frequency (UHF) region or decimeter band because the wavelength range is approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clusters), but these waves are sufficient to penetrate structures so that macrocells can provide service to UE 115 located indoors. Compared to communication using smaller frequencies and longer wavelengths in the lower frequencies (HF) or very high frequencies (VHF) portions of the spectrum below 300 MHz, communication using UHF waves can be associated with smaller antennas and shorter ranges (e.g., less than 100 km).

[0077] The wireless communication system 100 can also operate in the ultra-high frequency (SHF) region (also known as the centimeter band) in the range of 3 GHz to 30 GHz or in the extremely high frequency (EHF) region (e.g., 30 GHz to 300 GHz) (also known as the millimeter band) using the spectrum. In some aspects, the wireless communication system 100 can support millimeter-wave (mmW) communication between the UE 115 and the network entity 105 (e.g., base station 140, RU 170), and the EHF antennas of the corresponding devices can be smaller and more closely spaced compared to UHF antennas. In some aspects, such techniques facilitate the use of antenna arrays within the device. However, compared to SHF or UHF transmission, EHF transmission may experience even greater attenuation and a shorter range. The techniques disclosed herein can be adopted for transmission across one or more different frequency regions, and the frequency band usage specified across these frequency regions may vary by country or regulatory authority.

[0078] Wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, wireless communication system 100 may use unlicensed frequency bands (such as the 5 GHz Industrial, Scientific, and Medical (ISM) band) to employ Licensed Assisted Access (LAA), LTE Unlicensed (LTE-U) radio access technology, or NR technology. When operating using unlicensed RF spectrum bands, devices such as network entity 105 and UE 115 may employ carrier sensing for collision detection and avoidance. In some aspects, operation using unlicensed frequency bands may be combined with component carriers operating using licensed frequency bands based on carrier aggregation configurations (e.g., LAA). Operations using unlicensed spectrum may include downlink transmission, uplink transmission, P2P transmission, or D2D transmission, etc.

[0079] Network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of network entity 105 or UE 115 may be located within one or more antenna arrays or antenna panels, which can support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some aspects, the antennas or antenna arrays associated with network entity 105 may be located in different geographical locations. Network entity 105 may include an antenna array having a collection of multiple rows and columns of antenna ports that network entity 105 can use to support beamforming for communication with UE 115. Similarly, UE 115 may include one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0080] 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., network entity 105, UE 115) 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 achieved by combining signals transmitted via antenna elements of an antenna array such that some signals propagating in a particular direction relative to 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. 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).

[0081] Network entity 105 or UE 115 may use beam scanning technology as part of beamforming operations. For example, network entity 105 (e.g., base station 140, RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted multiple times by network entity 105 in different directions. For example, network entity 105 may transmit signals according to different beamforming weight sets associated with different transmission directions. Transmission along different beam directions may be used to identify (e.g., by a transmitting device (such as network entity 105) or by a receiving device (such as UE 115)) the beam direction for later transmission or reception by network entity 105.

[0082] Some signals (such as data signals associated with a specific receiving device) may be transmitted by a transmitting device (e.g., transmitting network entity 105, transmitting UE 115) along a single beam direction (e.g., the direction associated with the receiving device (such as receiving network entity 105 or receiving UE 115). In some aspects, the beam direction associated with transmission along a single beam direction may be determined based on the signals transmitted along one or more beam directions. For example, UE 115 may receive one or more signals transmitted by network entity 105 in different directions and may report to network entity 105 an indication of signals received by UE 115 with the highest signal quality or other acceptable signal quality.

[0083] In some aspects, transmissions performed by a device (e.g., by network entity 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital pre-decoding or beamforming to generate a combined beam for transmission (e.g., from network entity 105 to UE 115). UE 115 may report feedback indicating pre-decoding weights for one or more beam directions, and this feedback may correspond to a configured beam set across the system bandwidth or one or more subbands. Network entity 105 may transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)) that may or may not be pre-decoded. UE 115 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 network entity 105 (e.g., base station 140, RU 170) in one or more directions, UE 115 may use similar techniques to transmit signals multiple times in different directions (e.g., to identify the beam direction used by UE 115 for subsequent transmission or reception), or to transmit signals in a single direction (e.g., to transmit data to a receiving device).

[0084] A receiving device (e.g., UE 115) may perform reception operations according to multiple reception configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105). For example, the receiving device may perform reception according to multiple reception directions by: receiving via different antenna subarrays; processing the received signals according to different antenna subarrays; receiving according to different sets of reception beamforming weights (e.g., different sets of directional listening weights) applied to signals received at multiple antenna elements of the antenna array; or processing the received signals according to different sets of reception beamforming weights applied to signals received at multiple antenna elements of the antenna array, any of which may refer to “listening” according to different reception configurations or reception directions. In some aspects, the receiving device may use a single reception configuration to receive along a single beam direction (e.g., when a data signal is received). A single receiver configuration can be aligned along a beam direction determined based on listening according to different receiver configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0085] The wireless communication system 100 may be a packet-based network operating according to a layered protocol stack. In the user plane, communication at the bearer or PDCP layer may be IP-based. The RLC layer may perform packet segmentation and reassembly for communication via logical channels. The MAC layer may perform priority handling and multiplexing of logical channels to transport channels. The MAC layer may also use error detection, error correction, or both to support retransmission to improve link efficiency. In the control plane, the RRC layer may provide the establishment, configuration, and maintenance of RRC connections between the UE 115 and network entity 105 or core network 130 that support user plane data radio bearers. The PHY layer may map transport channels to physical channels.

[0086] The wireless communication system 100 can also be configured to communicate with one or more backscattering devices 190. The backscattering device 190 may be an RF energy harvesting device. Generally, RF energy harvesting devices are configured to capture ambient RF signals such as Wi-Fi, cellular, or radio signals and convert them into usable power, which can be used to perform one or more functions of the RF energy harvesting device. Some example RF energy harvesting devices can operate over a wide RF frequency range. The efficiency of these devices depends on various factors, such as antenna design and rectifier efficiency. The amount of energy harvested by an RF energy harvesting device is typically low and depends on the strength of the RF signal and the proximity of the device to the RF source (e.g., UE 115 and / or network entity 105).

[0087] RF energy harvesting devices are commonly used in applications such as wireless sensor networks, Internet of Things (IoT) devices, and other low-power electronic devices. These devices eliminate the need for traditional batteries or power sources, thereby reducing maintenance costs and improving the sustainability of these systems. RF energy harvesting devices can also supplement the power supply of other electronic devices, extending their battery life or reducing the need for frequent charging.

[0088] The basic architecture of an RF energy harvesting device may include an antenna, a rectifier, a microcontroller, and sensors. The antenna is designed to capture RF signals from the environment and convert those signals into an AC voltage signal. The rectifier is used to convert that AC signal into a DC voltage signal, which can be used to power the microcontroller and sensors. The microcontroller can read data from the sensors and control the antenna's reflection coefficient to perform backscatter modulation of the incoming RF signal, thereby transmitting data to one or more readers.

[0089] The backscatter modulation process may include two devices: a reader and a backscattering device. The reader transmits a continuous wave (CW) signal (e.g., an RF signal) to the backscattering device 190 at a specific frequency. The backscattering device 190 absorbs some of the energy of the signal and reflects the remaining energy back to the reader. By modulating the amplitude, phase, or frequency of the reflected signal, the backscattering device 190 can send information (e.g., data) to the reader.

[0090] Within the context of the wireless communication system 100, the reader may be one or more UEs 115 and / or network entities 105. This disclosure generally refers to the reader as a network node, where the term "network node" can encompass any device configured to receive backscatter communication from the backscatter device 190, including UE 115 and network entity 105. The backscatter device 190 may be a passive or semi-passive backscatter device, as such devices may lack internal storage capacity (e.g., passive backscatter device) or have very limited internal energy storage capacity (e.g., semi-passive backscatter device). In other cases, the backscatter device 190 may be referred to as a tag, EH tag, radio frequency identification (RFID) tag, passive UE (PUE), backscatter UE (BUE), environmental Internet of Things (IoT) device, passive IoT device, and / or wireless sensor node.

[0091] Figure 2 Examples of full-duplex communication between a reader and a backscattering device according to one or more aspects of this disclosure are illustrated. In one example, the reader is network entity 105. Figure 2 The network entity shown is a gNB. However, network entity 105 can be any type of base station. In another example, the reader is UE 115.

[0092] exist Figure 2 In the example, network entity 105 or UE 115 communicates with backscatter device 190 in full-duplex mode. Full-duplex communication means that the reader transmits continuous wave (CW) and forward link (FL) 200 to backscatter device 190, and then receives backscatter link (BL) 202 from backscatter device 190. FL may include control signaling for backscatter device 190. CW is an RF signal that serves as both the power source for backscatter device 190 and the carrier signal for backscatter communication. BL 202 carries data from backscatter device 190 to the reader.

[0093] Figure 3 Examples of half-duplex communication between multiple readers and a backscattering device according to one or more aspects of this disclosure are illustrated. Figure 3In the examples, different readers can handle different parts of the transmission and reception associated with backscatter device 190. In scenario 300, network entity 105 transmits CW and FL 200 to backscatter device 190. Then, backscatter device 190 transmits BL 202 to UE 115. Network entity 105 and UE 115 can communicate with each other via air interface (Uu) link 208. In scenario 310, UE 115 transmits CW and FL 200 to backscatter device 190. Then, backscatter device 190 transmits BL 202 to network entity 105. Again, network entity 105 and UE 115 can communicate with each other via Uu link 208.

[0094] Scenario 320 and Scenario 330 illustrate examples where the CW and FL are not the same signal. That is, the FL information may come from one reader, while the CW (e.g., an RF signal used for power supply) comes from a different reader. In Scenario 320, network entity 105 transmits CW 204 to backscatter device 190. However, UE 115 transmits FL 206 to the backscatter device. Backscatter device 190 transmits BL 202 to UE 115. In other examples, backscatter device 190 transmits BL 202 to network entity 105.

[0095] In scenario 330, UE 115 transmits CW 204 to backscatter device 190. However, network entity 105 transmits FL 206 to backscatter device 190. Backscatter device 190 transmits BL 202 to network entity 105. In other examples, backscatter device 190 transmits BL 202 to UE 115.

[0096] Figure 4 This is a block diagram illustrating an example backscatter communication between a reader and a backscatter device according to one or more aspects of this disclosure. Figure 4 A reader 400 communicating with backscatter device 190 is shown. Reader 400 can be any network node, such as UE 115 and / or network entity 105. Transmitter 402 of reader 400 can transmit RF signal 410. RF signal 410 can be CW or any ambient RF signal. RF signal 410 is received at antenna 420 of backscatter device 190. The received RF signal 410 represents the potential input power available for use by RF energy harvesting circuitry 430. Reference will be made below. Figure 5 Discuss technologies used for energy harvesting.

[0097] In backscatter communication, information transmission is performed via antenna modulation that does not involve active RF generation. The microcontroller 440 of backscatter device 190 tunes the reflection coefficient of its antenna 420 by switching a given set of impedances in a matching network 450, thereby generating varying amounts of modulated backscattered signals 460 (e.g., reflected power). The modulated backscattered signals 460 can be received and demodulated by the receiver 404 of reader 400.

[0098] When using Amplitude Shift Keying (ASK) modulation or On-Off Keying (OOK) modulation, the microcontroller 440 of the backscattering device 190 switches the value of the load impedance of the matching network 450 between a relatively high impedance and a relatively matched load. In the high-impedance case, the mismatch between the antenna 420 and the load impedance of the matching network 450 reflects most of the power back to the reader 400. In the matched case, most of the power from the incoming RF signal 410 is absorbed, and very little power is reflected back to the reader 400. In one example, the impedance switching frequency is based on the desired data rate.

[0099] When antenna 420 receives RF signal 410 with power P, this power is transmitted from antenna 420 to matching network 450, and simultaneously a portion of the power is transmitted from matching network 450 with reflection coefficient P. (For example, as in the Kurokawa formula) reflected to antenna 420, where Z A =R a +jX a It is the impedance of a complex antenna, and Z L =R L +jX L It is the impedance of the complex chip (load). Then, the reflected power |Γ| 2 P is radiated from antenna 420.

[0100] Figure 5 This is a block diagram of an example backscattering device according to one or more aspects of this disclosure. Figure 5 The RF energy harvesting circuit 430 is shown in more detail. In this example, the RF energy harvesting circuit 430 includes a rectifier 432 and a DC-DC converter 434. In some examples, a matching network 450 may also be considered as part of the RF energy harvesting circuit 430.

[0101] Matching network 450 operates as described above. Rectifier 432 is used to convert the RF signal to a DC voltage. Rectifier 432 may be specifically implemented based on a Schottky diode, a complementary metal-oxide-semiconductor (CMOS) diode, a reverse tunnel diode, or other similar diodes. The efficiency of the RF-DC conversion is a non-linear function of the input signal (e.g., power, waveform, and frequency) and may also depend on the configuration of DC-DC converter 434. As some examples, for a single-diode rectifier, the conversion efficiency may be 2% at 1µW, 15% at 10µW, and 35% at 100µW.

[0102] The voltage of the DC signal from rectifier 432 is typically several hundred mV, such as 300 mV. DC-DC converter 434 boosts the voltage of the DC signal output from rectifier 432 to a predetermined target voltage (e.g., 1.8V to 2.4V). In some examples, DC-DC converter 434 has a minimum input voltage threshold (e.g., 300 mV) below which it cannot operate. In some examples, due to cold-start limitations, DC-DC converter 434 may be configured to operate at a higher voltage threshold for battery-free backscattering device configurations. For DC-DC conversion, the delay time from when input power is available until the output reaches the target voltage can be long (depending on the size of the capacity used), for example, from hundreds of microseconds to several seconds.

[0103] In some examples, single-diode rectifier configurations are preferred for low power (1uW to 500uW). For higher input power (>500uW), multi-diode rectifiers may be preferred. Example multi-diode rectifier configurations may include voltage doublers, diode bridges, and charge pumps.

[0104] Battery-free backscattering configurations can be configured to start all hardware components from a cold start state (0V), while battery-rechargeable backscattering configurations can use a connected battery to provide a non-zero voltage value, thus achieving higher sensitivity. Below -30dBm (1uW), Schottky diodes are not easily turned on.

[0105] In some example configurations, the backscatter device 190 may be configured to power on the backscatter device 190 once the reader has transmitted an RF signal (e.g., CW) for a predetermined duration (e.g., at least 400 µs, greater than 400 µs, or 0 µs to 1500 µs). In some examples, the minimum RF input power to the backscatter device 190 is -20 dBm.

[0106] Recently, ambient IoT (e.g., passive IoT) technologies have garnered attention within 3GPP. Some example ambient IoT technologies aim to create low-complexity, low-power devices, with complexity and power consumption several orders of magnitude lower than existing technologies such as enhanced machine-type communication (eMTC) and / or narrowband IoT (NB-IoT). Ambient IoT devices (e.g., backscatter devices 190) are generally categorized into two types. Type A ambient IoT devices are devices without energy storage capabilities (e.g., no battery) and rely entirely on the availability of an external power source (e.g., RF signal / CW). Type B ambient IoT devices have limited energy storage (e.g., supercapacity or conventional capacity) that does not require manual replacement or recharging.

[0107] As described above, environmental IoT devices (such as backscatter device 190) are typically passive devices and do not have active RF components. Instead, environmental IoT devices use backscatter modulation to transmit data. For example, backscatter device 190 may perform data transmission based on modulation of incident RF signals transmitted by an environmental transmitter (e.g., UE 115 and / or network entity 105). The environmental RF signal serves not only as a signal resource for backscatter modulation but also as an energy resource for harvesting.

[0108] RFID is an existing battery-free technology; however, its limited read range of only a few meters makes it difficult to support large-scale deployments with seamless coverage. Current backscatter and / or energy harvesting devices, such as RFID, may exhibit the following drawbacks.

[0109] Currently, power control of backscattering devices (e.g., controlling the power of ambient RF signals) is challenging because the reader lacks any mechanism to determine the amount of power collected by the backscattering device. In some examples, the backscattering device may operate based on a minimum RF input power requirement for energy harvesting (e.g., -20 dBm for a battery-less device). However, excessive input power can overcharge the rectifier and lead to energy waste. Therefore, it is preferable that the power collected by the backscattering device provides the minimum level of power required to harvest power from the RF signal from the reader and to modulate the signal backscattered back to the reader.

[0110] For backscatter communication, higher data rates can be achieved by switching antenna impedance at faster frequencies. However, faster antenna switching frequencies can increase power consumption. Therefore, the maximum data rate is often determined by the power collected, especially for battery-less devices where power comes directly from the incoming RF signal.

[0111] Therefore, information indicating the power collected at a passive backscattering device can be beneficial for more efficient scheduling of backscattering communications with the reader. Furthermore, information indicating the power collected at a passive backscattering device can also enable the reader to perform power control on RF signals (e.g., CW) to support more efficient energy harvesting.

[0112] Another issue with some example backscatter devices relates to the initial power-on duration and transmission periodicity of ambient RF signals (e.g., CW). For backscatter devices with limited energy storage, when the backscatter device loses power due to an unavailable power source and cannot provide sufficient power to charge the backscatter device's microcontroller and / or storage elements, the available voltage on the backscatter device may drop below a critical level, causing the backscatter device's circuitry to enter a sleep state (e.g., a cold start state).

[0113] To prevent entering a cold start state (where the initial charging time can be long, for example, hundreds of milliseconds depending on the connection capacity), it is preferable to periodically send RF signals to the backscattering device to keep it active. However, if the backscattering device is in good power condition or has no data to send, periodic RF signal transmission may result in wasted energy. Periodic RF signal transmission may also cause unnecessary interference to communication signals.

[0114] This disclosure describes techniques for addressing one or more of the aforementioned problems with passive backscattering devices. Specifically, this disclosure describes various signaling techniques that allow one or more readers to determine an optimal amount of power for an ambient RF signal used by the backscattering device to collect energy and transmit data via backscatter modulation. Furthermore, the techniques of this disclosure allow readers to determine an optimal periodicity for transmitting RF signals to the backscattering device, thereby reducing the likelihood of the backscattering device entering a cold start state. For certain use cases, preventing the backscattering device from entering a cold start state can improve data transmission speed and / or data transmission reliability.

[0115] Figure 6This is a block diagram illustrating example techniques for power control in a backscattering device according to one or more aspects of the present disclosure. According to the techniques of the present disclosure, a network node (e.g., UE 115 and / or network entity 105) may be configured to communicate with one or more backscattering devices 190. In one example, the backscattering device 190 may be configured to transmit information 194 indicating the power preferences of the backscattering device 190 to a first network node 192. Examples of the information indicating the power preferences will be described in more detail below. The backscattering device 190 may receive an RF signal 196 from the first network node 192, wherein the RF signal 196 is based on information 194. For example, the network node 192 may use the information indicating the power preferences of the backscattering device 190 to determine parameters of the RF signal. Such parameters may include the power, waveform, and / or frequency of the RF signal. In other examples, the network node 192 may determine the timing and / or periodicity used to transmit the RF signal. The backscattering device 190 may then transmit data 198 to the network node 192 or to another network node based on backscatter modulation of the RF signal 196.

[0116] The following are examples of both open-loop and closed-loop power control performed on backscattering device 190 using different types of information indicating power preferences. In some examples, network node 192 may perform open-loop power control of RF signal 196 without direct feedback from backscattering device 190. In other examples, network node 192 may perform closed-loop power control including feedback from backscattering device 190. Each technique described below may be used alone or in any combination with any other technique. That is, each example of information indicating power preferences in the following examples should not be considered mutually exclusive.

[0117] The relationship between the power available for harvesting from RF signal 196 and the modulated backscattered power of data 198 (e.g., the total power of the two sidebands of the backscattered wave, excluding the carrier power) can be described as follows. For two impedance states, the RF power available for generating DC power (e.g., energy harvesting) is given by the following formula: P RF,in =P avail (p1(1-|Γ1| 2 )+p2(1-|Γ2| 2 )), where P RF,in It is the power that can be collected, p 1,2 Γ is the probability that the backscattering device 190 is in one of these two impedance states. 1,2 The reflection coefficient depends on the modulation type, and P availThis refers to the power (e.g., RF signal 196) that can be obtained from the antenna of the backscattering device 190. These two impedance states correspond to relatively high impedance and relatively matched loads, such as those described above with respect to ASK modulation and OOK modulation.

[0118] The modulated backscattered power in data 198 also depends on the reflection coefficient and the antenna loss factor. For example, the modulated backscattered power P bs This can be determined as follows: Where L ant This refers to antenna loss. In the preceding description, it is assumed that p1 = p2 = 0.5 (i.e., the probability of each impedance state is the same).

[0119] Therefore, if the reflection coefficient is known, the collected power available for use by the backscattering device 190 can be derived from the modulated backscattered power. Thus, in one example of this disclosure, the information 194 indicating power preference may be data indicating the supported modulation type, the number of impedance states, and the reflection coefficient associated with the modulation type used by the backscattering device 190. The backscattering device 190 may transmit the information indicating the supported modulation type, the number of impedance states, and the associated reflection coefficient to the network node 192.

[0120] Then, network node 192 can determine the power (P) available for energy harvesting in the following way. RF,in ): Measure the power (P) of the backscattered signal (e.g., data 198). bs Network node 192 can use power P. bs In addition to information indicating modulation, impedance, and associated reflection coefficients, P is determined according to the above relationships. RF,in Then, network node 192 can, based on the requirements of the backscatter device 190's use case, adjust the power level (P) accordingly. avail Transmit RF signal 196 to achieve P RF,in The target level.

[0121] For example, if network node 192 determines P RF,in If the power of the RF signal 196 is less than a certain target power (P0), the transmitter of the RF signal 196 (e.g., network node 192 or some other separate RF source) may be configured and / or instructed to increase the transmission power of the RF signal 196 transmitted to the backscattering device 190. Otherwise, network node 192 or another RF source may reduce the transmission power of the RF signal 196 until the target power (P0) is reached. The target power (P0) may be communicated to network node 192 by another network entity 105, another UE 115, or by backscattering device 190. The foregoing is an example of open-loop power control of this disclosure.

[0122] In the above example, three modulation types can be defined. One modulation type can be amplitude shift keying (ASK) with power mismatch in one impedance state (Γ1 = 0) and total reflection in another impedance state (|Γ2| = 1). Another modulation type can be where the mismatch is equal in both impedance states (Γ1 = 0). 1,2 Phase shift keying (PSK) with impedance equal to ±jm. Another modulation type is where the mismatch is equal in both impedance states (Γ). 1,2 =±m) of ASK. For the latter two types, the modulation index m can be reported as the reflection coefficient to network node 192. Variable Γ 1,2 The representation is defined as follows: The reflection coefficient for each impedance state, where Z is the reflection coefficient for each impedance state. 1,2 It is the equivalent complex impedance of the backscattering device integrated circuit, which may include resistance and capacitance, for example

[0123] Z 1,2 =R 1,2 +jX 1,2 (R 1,2 It is a resistor, and X 1,2 It is a capacitor, in which ).

[0124] In another example of this disclosure, the information 194 indicating power preference transmitted from the backscattering device 190 to the network node 192 may include the following power ratio (P) between the two. RF,in / P bs ): Power (P) that can be collected from RF signal 196 RF,in ) and the power of backscatter modulation of the RF signal (P) bs (For example, the power of data 198). The power ratio can also be referred to as the power ratio difference.

[0125] The following are example power ratios for different modulation types. Of course, other power ratios can also be used for different backscatter modulation types. For an ASK modulation type with power mismatch in the on state (Γ1 = 0) and total reflection in the other state (|Γ2| = 1), 50% of the input power can be used for rectification, 25% is used as backscatter modulation power, and the remaining 25% is wasted. Therefore, the power ratio difference is 10*log10(2) = 3dB. For a mismatch equal in both states (Γ1 = 0), the power ratio difference is 10*log10(2) = 3dB. 1,2 =±jm) and In the PSK modulation type, 83% of the input RF wave power can be used for rectification, and 17% is used as backscatter modulation power. Therefore, the difference is 10*log10(83 / 17) = 6.88dB. For the mismatch to be equal in both states (Γ... 1,2 =±m) and For the ASK modulation type, assuming modulation is achieved by switching a series resistor between two states, 49% of the input RF wave power can be used for rectification, 17% is used as backscatter modulation power, and the remaining 34% is wasted. Therefore, the difference is 10*log10(49 / 17) = 4.6dB.

[0126] In some examples, the backscattering device 190 is configured to directly measure P. bs and P RF,in To determine the power ratio. In other examples, the power ratio difference can be pre-calculated based on the reflection coefficient and / or by laboratory measurements, and the power ratio can be stored in memory at backscattering device 190.

[0127] Network node 192 can determine the available power (P) for energy harvesting in the following ways. RF,in ): Measure the received power (P) of the backscattered signal (e.g., data 198). bs,rx Then, P is determined based on the difference in received power ratio. RF,in Then, network node 192 can, based on the requirements of the backscatter device 190's use case, adjust the power level (P) accordingly. avail Transmit RF signal 196 to achieve P RF,in The target level.

[0128] Similarly, if network node 192 determines P RF,in If the power of the RF signal 196 is less than a certain target power (P0), the transmitter of the RF signal 196 (e.g., network node 192 or some other separate RF source) may be configured and / or instructed to increase the transmission power of the RF signal 196 transmitted to the backscattering device 190. Otherwise, network node 192 or another RF source may reduce the transmission power of the RF signal 196 until the target power (P0) is reached. The target power (P0) may be communicated to network node 192 by another network entity 105, another UE 115, or by backscattering device 190. The foregoing is another example of open-loop power control of this disclosure.

[0129] As an example of using the power ratio difference, network node 192 can determine P as follows: RF,in :P RF,in =P bs,Rx +PL+Δ, where PL is the path loss and Δ is the power ratio difference of the modulated backscattered power. In some examples, the power ratio difference can be indicated by the backscattering device 190 in information 194, as described above. In other examples, the power ratio difference can be derived by network node 102 from the reflection coefficient and modulation type (e.g., as indicated in information 194).

[0130] Generally, in the above example of open-loop power control, network node 192 can be configured to estimate the available power of RF signal 196 at backscattering device 190 based on the received power of the backscattered modulation of the RF signal and information 194 indicating power preference. Then, network node 192 can determine the transmit power of RF signal 196 based on the available power of the RF signal at backscattering device 190 and based on the target power (P0).

[0131] The following describes examples of closed-loop power control that can be used in conjunction with the open-loop power control techniques described above, or used alone.

[0132] In one example, backscattering device 190 may (e.g., in information 194) transmit an indication of increasing or decreasing the transmission power of RF signal 196. In one example, backscattering device 190 may be configured to measure the power transmitted by RF energy harvesting circuitry 430 (see [link to information]). Figure 4 The actual power collected is used to transmit an indication to increase or decrease the transmit power of RF signal 196 based on its measurement. In one example, the indication to increase or decrease the transmit power could be a transmit power control (TPC) command. See also Figure 4 The backscattering device 190 may also include an analog-to-digital converter (ADC) between the RF energy harvesting circuitry 430 and the microcontroller 440 for measuring the actual harvested power. Therefore, support for closed-loop power control in the backscattering device 190 may be capability-based (e.g., the presence of energy measurement circuitry) and is not mandatory.

[0133] In the closed-loop power control example of this disclosure, backscattering device 190 may be configured to measure the power of an RF signal available for collection and transmit information to network node 192 indicating a request to increase or decrease the power of a subsequent RF signal. Similarly, in some examples, this request may be a TPC command. Likewise, network node 192 may be configured to receive information from backscattering device 190 indicating a request to increase or decrease the power of a subsequent RF signal and transmit the subsequent RF signal to backscattering device 190 based on the request.

[0134] In another example of this disclosure, a backscattering device with limited energy storage (such as backscattering device 190) may report a preferred minimum periodicity for receiving RF signal 196 in information 194 based on its service mode and latency requirements for services originating from the device (e.g., for sensing data transmission). The preferred mode for receiving RF signal at backscattering device 190 may include a minimum periodicity for receiving RF signal, a signal time window per cycle, and short periodicity for signal transmission within the window. In some examples, the preferred mode for receiving RF signal may follow nested outer and inner discontinuous reception (DRX) cycles supported by extended discontinuous reception (eDRX) mode configurations.

[0135] eDRX is a feature in 5G cellular networks that enables devices to reduce power consumption by extending the time between radio receive cycles. In 5G, eDRX is used to conserve battery life for battery-powered IoT devices that participate in intermittent or sporadic data communications. By extending the time between radio receive cycles, devices can remain in a low-power mode for a longer period, ultimately extending battery life. eDRX allows devices to wake from sleep mode only when they need to receive data, rather than remaining continuously active, thus significantly reducing power consumption.

[0136] Network node 192 can transmit RF signals 196 (or RF packets) at minimal intervals to prevent backscatter device 190 from entering a cold start. In this way, backscatter device 190 can be woken up more quickly when there is data to send or receive.

[0137] In one example, the eDRX periodicity can be used as a baseline for the minimum periodicity used to receive RF signals. In some examples, the minimum periodicity value can be a power of 2: 5.12 seconds, 10.24 seconds…2621.44 seconds (43.69 minutes); or it can be a non-power of 2: 10.24*(6,10,12,14) = 61.44 seconds, 102.4 seconds, 122.88 seconds, 143.36 seconds. In some examples, when the minimum periodicity is greater than 10.24 seconds, a time window for energy harvesting per cycle can be defined, during which the RF signal is transmitted with a second smaller periodicity.

[0138] Figure 7 This is a timing diagram 700 for transmitting RF signals for energy harvesting according to one or more aspects of this disclosure. The timing diagram shows supersystem frame numbers (SFNs) from 0 to 1023. Each super SFN comprises 1024 frames within 10.24. A long cycle (T) of the energy timing window (ETW) 720 (e.g., minimum periodicity) is also shown. LStarting from the offset of SFN X, the backscattering device 190 transmits information indicating that an RF signal will be received in the ETW 720. Within the ETW 720, the backscattering device can further define the signal time window per cycle and the short periodicity within the window for signal transmission. The signal time window per cycle is shown as Y, Y+T. S Y+2*T S Where Y is the first SFN at which RF signal 196 is received, and T S It is the time between RF signals (e.g., short cycles of 730 or short periods within a window used for signal transmission).

[0139] Therefore, in this example, the information 194 indicating power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving subsequent RF signals, or periodicity for signal transmission within the signal time window. Network node 192 may be configured to transmit RF signals 196 to backscatter device 190 with a minimum periodicity (e.g., ETW 720). In some examples, network node 192 may also be configured to transmit RF signals 196 within each signal time window (e.g., within...). Figure 7 (at HFN Y in the signal) and / or transmit RF signals in short periods (e.g., based on short cycle 730) within the signal time window.

[0140] Generally, backscattering device 190 can receive periodic RF signals within a time window. If there is any data to transmit, backscattering device 190 can backscatter modulated RF signals to carry the data. If there is no data to report, backscattering device 190 may not backscatter modulate the RF signals. Based on the detection of the modulated backscattered signals, network node 192 can determine whether there is data transmission from backscattering device 190. If there is no data from backscattering device 190, network node 192 can stop transmitting the remaining RF signals within the time window. In other words, the time window is used not only for periodic energy harvesting but also for periodic backscattering of traffic originating from any device.

[0141] In another example of this disclosure, network node 192 may be configured to transmit configuration information to other RF power transmitters (e.g., other network nodes), including information indicating the power preferences of backscattering device 190. The information indicating the power preferences of the backscattering device may include one or more of DRX configuration, duration, frequency resources, or the region or location of the backscattering device. In this way, more readers near backscattering device 190 may be configured to execute the power control features of this disclosure. The DRX configuration may include a minimum periodicity for transmitting RF signals, a signal time window per cycle, and short periods within the window for signal transmission.

[0142] In some examples, only readers or RF power transmitters located within a threshold distance (e.g., within an indicated area or location) of the backscattering device 190 are configured to transmit RF signals 196 on a configured time or frequency resource. Location information allows additional readers to determine how much power to use or whether to transmit. For example, a network node (e.g., a reader) may determine its proximity to the backscattering device (e.g., within a threshold distance) based on the device's location and transmit RF signals to it based on the proximity of a first network node to the backscattering device.

[0143] Figure 8 This is a call flowchart illustrating an example of carrier transmit power control according to one or more aspects of this disclosure. Figure 8 As shown, network node 192 can transmit a carrier wave (e.g., an RF signal, CW, or ambient NR) to backscattering device 190. Backscattering device 190 transmits a reflection coefficient and / or a modulated backscattered power ratio (e.g., located in information indicating power preference) to network node 192 via backscatter modulation. Network node 192 can measure the modulated backscattered power and estimate the available power for collection at backscattering device 190. Based on the estimated available power for collection, network node 192 can determine the power of a subsequent carrier wave (e.g., RF signal 196) by comparing the estimated available power for collection with a target power. That is, the network node can perform carrier transmission based on open-loop power control (OLPC).

[0144] In another example, backscattering device 190 can also be configured to perform measurements on the collected power and determine a TPC command. That is, backscattering device 190 can determine whether to request an increase or decrease in carrier power. Backscattering device 190 can then transmit a TPC command for the carrier to network node 192. This TPC command can be a single bit that instructs network node 192 to increase or decrease power. This TPC command is an example of closed-loop power control (CLPC).

[0145] Figure 9 This is a call flowchart illustrating another example of carrier transmit power control according to one or more aspects of this disclosure. Figure 9 As shown, network node 192 can transmit a carrier wave (e.g., RF signal, CW, or ambient NR, etc.) to backscatter device 190. Backscatter device 190 transmits information via backscatter modulation indicating a preferred minimum periodicity for receiving future energy signals / packets (e.g., carrier wave, RF signal, CW, or ambient NR, etc.). Network node 192 can be configured to transmit configuration information to other RF sources 199. This configuration information can be for energy signal / packet transmission (Tx) configuration and includes one or more of the following information, or any information already disclosed above: information indicating the periodicity of energy packets, the duration of energy packets, time and / or frequency resources, area (e.g., location) information.

[0146] Both network node 192 and RF source 199 can transmit energy signals / packets to backscatter device 190. Backscatter device 190 can perform energy harvesting from multiple RF sources and / or readers (e.g., network node 192 and RF source 199). Backscatter device 190 can then transmit traffic (e.g., data) originating from a mobile device to network node 192. In this case, the traffic originating from the mobile device is a backscatter transmission originating from backscatter device 190.

[0147] Figure 10 This is a block diagram illustrating an example of a hardware implementation for a network node 1000 (e.g., UE 115 and / or network entity 105) employing a processing system 1014. For example, the network node 1000 may be as follows: Figure 1 The UE 115 and / or network entity 105 are illustrated in the example.

[0148] Network node 1000 may include a processing system 1014 having one or more processors 1004. Examples of processors 1004 include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic components, discrete hardware circuitry, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. In various examples, network node 1000 may be configured to perform any one or more of the functions described herein. For example, processor 1004 utilized in network node 1000 may be configured (e.g., in coordination with memory 1005) to implement any or more of the processes and procedures described above for open-loop and / or closed-loop power control of backscattering devices.

[0149] Processing system 1014 may be implemented using a bus architecture typically represented by bus 1002. Bus 1002 may include any number of interconnect buses and bridges, depending on the specific application of processing system 1014 and overall design constraints. Bus 1002 communicatively couples together various circuits including one or more processors (typically represented by processor 1004), memory 1005, and computer-readable media (typically represented by computer-readable media 1006). Bus 1002 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further. Bus interface 1008 provides an interface between bus 1002 and transceiver 1010. Transceiver 1010 provides a communication interface or component for communicating with various other devices via a transmission medium. Depending on the nature of the device, user interface 1012 (e.g., keypad, display, speaker, microphone, joystick) may also be provided. Of course, such user interface 1012 is optional, and in some examples (such as base stations), it may be omitted.

[0150] In some aspects of this disclosure, processor 1004 may include power control circuitry 1040 configured (e.g., coordinated with memory 1005) for various functions, including, for example, open-loop and / or closed-loop power control of a backscattering device according to the techniques of this disclosure described herein. Generally, network node 1000 may be configured to receive information from the backscattering device indicating the power preference of the backscattering device. Network node 1000 may transmit RF signals to the backscattering device (wherein the RF signals are based on the information) and receive data from the backscattering device based on backscattering modulation of the RF signals by the backscattering device.

[0151] Processor 1004 is responsible for managing bus 1002 and general processing, including executing software stored on computer-readable medium 1006. When executed by processor 1004, this software causes processing system 1014 to perform the various functions described above for any particular device. Processor 1004 may also use computer-readable medium 1006 and memory 1005 to store data manipulated by processor 1004 while executing the software.

[0152] One or more processors 1004 in the processing system execute software. Software should be broadly interpreted as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or others. The software may reside on a computer-readable medium 1006. The computer-readable medium 1006 may be a non-transitory computer-readable medium. Non-transitory computer-readable media include, for example, magnetic storage devices (e.g., hard disks, floppy disks, magnetic stripes), optical disks (e.g., compact discs (CDs) or digital versatile discs (DVDs)), smart cards, flash memory devices (e.g., card, stick, or key drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other suitable medium for storing software and / or instructions accessible and readable by a computer. Computer-readable medium 1006 may reside in processing system 1014, be located outside processing system 1014, or be distributed across multiple entities including processing system 1014. Computer-readable medium 706 may be implemented in a computer program product. For example, a computer program product may include a computer-readable medium in encapsulation material. Those skilled in the art will recognize how best to implement the functionality described throughout this disclosure depends on the specific application and the overall design constraints imposed on the system.

[0153] In one or more examples, computer-readable storage medium 1006 may store computer-executable code including power control instructions 1052 configured for various functions, including, for example, open-loop and / or closed-loop power control of a backscattering device according to the technology of this disclosure described herein. Power control instructions 1052 may be configured to cause network node 1000 to: receive information from the backscattering device indicating the power preference of the backscattering device; transmit an RF signal to the backscattering device, wherein the RF signal is based on the information; and receive data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0154] In one configuration, an apparatus for wireless communication includes: components for receiving information from a backscattering device indicating the power preference of the backscattering device; components for transmitting an RF signal to the backscattering device, wherein the RF signal is based on the information; and components for receiving data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device. In one aspect, the aforementioned components may be a processor 1004 including power control circuitry 1040, the processor being configured to perform the functions described by the aforementioned components. In another aspect, the aforementioned components may be circuitry or any apparatus configured to perform the functions described by the aforementioned components.

[0155] Of course, in the above examples, the circuitry included in processor 1004 is provided merely as an example, and other components for performing the described functions may be included in various aspects of this disclosure, including but not limited to instructions stored in computer-readable storage medium 1006, or described in any of the figures and utilized, for example, as described above and hereinafter. Figure 11 and / or Figure 12 Any other suitable device or component of the described process and / or algorithm.

[0156] Figure 11 This is a flowchart illustrating an exemplary process 1100 for power control in a backscattering device. The techniques of process 1100 can be performed by the backscattering device 190 described herein.

[0157] In one example, backscattering device 190 may be configured to transmit information indicating the device's power preferences to a first network node (e.g., UE 115 and / or network entity 105) (1110). Backscattering device 190 may also receive RF signals from the first network node, wherein the RF signals are based on the information (1120). Backscattering device 190 may also transmit data to one or more of the first or second network nodes based on backscattering modulation of the RF signals (1130).

[0158] In one example, the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

[0159] In another example, the information indicating the power preference includes the ratio between a first power that can be obtained from the RF signal and a second power that is modulated by the backscattering of the RF signal.

[0160] In another example, the backscattering device 190 is also configured to measure the power of the RF signal and transmit information to the first network node indicating a request to increase or decrease the power of subsequent RF signals.

[0161] In another example, the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or the periodicity for signal transmission within the signal time window.

[0162] Figure 12 This is a flowchart illustrating an exemplary process 1200 for power control in a backscatter device. The techniques of process 1200 may be performed by a network node 192 (such as UE 115 and / or network entity 105) as described herein.

[0163] In one example, network node 192 may be configured to receive information (1210) from a backscattering device indicating the power preference of the backscattering device. Network node 192 may transmit a radio frequency (RF) signal (based on the information) to the backscattering device (1220) and receive data from the backscattering device based on the backscattering modulation of the RF signal by the backscattering device (1230).

[0164] In one example, the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

[0165] In another example, the information indicating the power preference includes the ratio between a first power that can be obtained from the RF signal and a second power that is modulated by the backscattering of the RF signal.

[0166] In another example, network node 192 is also configured to estimate the available power of the RF signal at the backscattering device based on the received power of the backscatter modulation of the RF signal and the information indicating the power preference. Network node 192 may also determine the transmit power of the RF signal based on the available power of the RF signal at the backscattering device and based on the target power.

[0167] In another example, network node 192 is also configured to receive information from the backscattering device indicating a request to increase or decrease the power of a subsequent RF signal, and to transmit the subsequent RF signal to the backscattering device based on the request.

[0168] In another example, the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or periodicity for signal transmission within the signal time window. In this example, network node 192 is configured to transmit one or more subsequent RF signals to the backscattering device based on this information.

[0169] In another example, network node 192 is a first network node and is also configured to receive configuration information from one or more second network nodes, the configuration information including information indicating the power preference of the backscattering device. In this example, the information indicating the power preference of the backscattering device includes one or more of DRX configuration, duration, frequency resources, or the location of the backscattering device. The network node may also be configured to determine that the first network node is near the backscattering device based on the location of the backscattering device, and to transmit the RF signal to the backscattering device based on the proximity of the first network node to the backscattering device.

[0170] The following numbered clauses illustrate one or more aspects of the devices and technologies described in this disclosure.

[0171] Aspect 1 - An apparatus for passive wireless communication, the apparatus comprising: one or more processors and a memory accessible by the one or more processors, wherein the one or more processors are configured to: transmit information indicating the power preference of the apparatus to a first network node; receive a radio frequency (RF) signal from the first network node, wherein the RF signal is based on the information; and transmit data to one or more of the first network node or a second network node based on backscatter modulation of the RF signal.

[0172] Aspect 2 - The apparatus according to aspect 1, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

[0173] Aspect 3 - An apparatus according to any one of Aspects 1 to 2, wherein the information indicating the power preference includes a ratio between a first power that can be obtained from the RF signal and a second power that is modulated by the backscattering of the RF signal.

[0174] Aspect 4 - An apparatus according to any one of Aspects 1 to 3, wherein the one or more processors are further configured to: measure the power of the RF signal; and transmit information to the first network node indicating a request to increase or decrease the power of a subsequent RF signal.

[0175] Aspect 5 - An apparatus according to any one of Aspects 1 to 4, wherein the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or periodicity for signal transmission within the signal time window.

[0176] Aspect 6 - The apparatus according to any one of aspects 1 to 5, wherein the first network node is a reader.

[0177] Aspect 7 - The apparatus according to aspect 6, wherein the reader is one or more of a user equipment (UE) or a base station.

[0178] Aspect 8 - The apparatus according to any one of aspects 1 to 7, wherein the RF signal is a continuous wave.

[0179] Aspect 9 - An apparatus according to any one of aspects 1 to 8, wherein the apparatus is a passive or semi-passive backscattering device.

[0180] Aspect 10 - A network node for passive wireless communication, the network node comprising: one or more processors and a memory accessible by the one or more processors, wherein the one or more processors are configured to: receive information from a backscattering device indicating a power preference of the backscattering device; transmit a radio frequency (RF) signal to the backscattering device, wherein the RF signal is based on the information; and receive data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0181] Aspect 11 - A network node according to aspect 10, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

[0182] Aspect 12 - A network node according to any one of Aspects 10 to 11, wherein the information indicating the power preference includes a ratio between a first power that can be obtained from the RF signal and a second power that is modulated by the backscattering of the RF signal.

[0183] Aspect 13 - A network node according to any one of Aspects 10 to 12, wherein the one or more processors are further configured to: estimate the available power of the RF signal at the backscattering device based on the received power of the backscatter modulation of the RF signal and the information indicating the power preference.

[0184] Aspect 14 - A network node according to aspect 13, wherein the one or more processors are further configured to: determine the transmission power of the RF signal based on the available power of the RF signal at the backscattering device and based on the target power.

[0185] Aspect 15 - A network node according to any one of Aspects 10 to 14, wherein the one or more processors are further configured to: receive from the backscattering device information indicating a request to increase or decrease the power of a subsequent RF signal; and transmit the subsequent RF signal to the backscattering device based on the request.

[0186] Aspect 16 - A network node according to any one of Aspects 10 to 15, wherein the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or periodicity for signal transmission within the signal time window; and wherein the one or more processors are configured to: transmit one or more subsequent RF signals to the backscattering device based on the information.

[0187] Aspect 17 - A network node according to any one of Aspects 10 to 16, wherein the network node is a first network node, and wherein the one or more processors are further configured to:

[0188] Configuration information is received from one or more second network nodes, the configuration information including information indicating the power preference of the backscattering device.

[0189] Aspect 18 - A network node according to aspect 17, wherein the information indicating the power preference of the backscattering device includes one or more of DRX configuration, duration, frequency resources, or the location of the backscattering device.

[0190] Aspect 19 - A network node according to aspect 18, wherein the one or more processors are further configured to: determine that the first network node is near the backscattering device based on the location of the backscattering device; and send the RF signal to the backscattering device based on the fact that the first network node is near the backscattering device.

[0191] Aspect 20 - The method according to any one of aspects 10 to 19, wherein the first network node is a reader.

[0192] Aspect 21 - A network node according to aspect 20, wherein the reader is one or more of a user equipment (UE) or a base station.

[0193] Aspect 22 - A network node according to any one of aspects 10 to 21, wherein the RF signal is a continuous wave.

[0194] Aspect 23 - A network node according to any one of aspects 10 to 22, wherein the backscattering device is a passive or semi-passive backscattering device.

[0195] Aspect 24 - A method for passive wireless communication by a backscattering device, the method comprising: transmitting to a first network node information indicating a power preference of the backscattering device; receiving a radio frequency (RF) signal from the first network node, wherein the RF signal is based on the information; and transmitting data to one or more of the first network node or a second network node based on backscattering modulation of the RF signal.

[0196] Aspect 25 - The method according to aspect 24, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

[0197] Aspect 26 - The method according to any one of Aspects 24 to 25, wherein the information indicating the power preference includes a ratio between a first power that can be obtained from the RF signal and a second power that is modulated by the backscattering of the RF signal.

[0198] Aspect 27 - A method for passive wireless communication, the method comprising: receiving from a backscattering device information indicating a power preference of the backscattering device; transmitting a radio frequency (RF) signal to the backscattering device, wherein the RF signal is based on the information; and receiving data from the backscattering device based on backscattering modulation of the RF signal by the backscattering device.

[0199] Aspect 28 - The method according to aspect 27, the method further comprising: estimating the available power of the RF signal at the backscattering device based on the received power of the backscatter modulation of the RF signal and the information indicating the power preference.

[0200] Aspect 29 - The method according to aspect 28 further includes:

[0201] The transmission power of the RF signal is determined based on the available power of the RF signal at the backscattering device and based on the target power.

[0202] Aspect 30 - The method according to any one of Aspects 27 to 29, the method further comprising: receiving from the backscattering device information indicating a request to increase or decrease the power of a subsequent RF signal; and transmitting the subsequent RF signal to the backscattering device based on the request.

[0203] While aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for illustrative purposes, and the terms LTE, LTE-A, LTE-A Pro, or NR may be used in most of the description, the techniques described herein are also applicable to networks outside of LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described are applicable to a variety of other wireless communication systems, such as Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0204] The information and signals described herein can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0205] The various exemplary blocks and components described herein can be implemented or performed using a general-purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic component, discrete hardware component, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternative embodiments, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration).

[0206] The functionality described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functionality may be stored as one or more instructions or code on or transmitted via a computer-readable medium. Other examples and specific implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functionality described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination of these. Features implementing the functionality may also be physically located in different locations, including being distributed such that portions of the functionality are implemented at different physical locations.

[0207] Computer-readable media includes both non-transitory computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one location to another. Non-transitory storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compressed optical disc (CD) ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code components in the form of instructions or data structures, and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Furthermore, any connection is appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of computer-readable media. As used in this article, disks and optical discs include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while optical discs reproduce data optically using lasers. Combinations of these are also included within the scope of computer-readable media.

[0208] As used herein, the word "or" used in the list of items in the claims (e.g., a list of items followed by phrases such as "at least one of" or "one or more of") indicates an inclusive list, such that, for example, a list of at least one of A, B, or C represents A or B or C or AB or AC or BC or ABC (in other words, A and B and C). Furthermore, as used herein, the phrase "based on" should not be construed 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 construed as "at least based on A," unless specifically stated otherwise.

[0209] In the accompanying drawings, similar components or features may have the same reference numerals. Furthermore, various components of the same type can be distinguished by adding a dash after the reference numeral and a second numeral for differentiation between similar components. If only the first reference numeral is used in the specification, the description can be applied to any of the similar components having the same first reference numeral, regardless of the second or other subsequent reference numerals.

[0210] This document describes exemplary configurations in conjunction with the accompanying drawings and does not represent all achievable or within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration," rather than "preferred" or "advantageous over other examples." The detailed description includes specific details used to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some cases, known structures and devices are shown in block diagram form to avoid obscuring the concept of the described examples.

[0211] The description provided herein is intended to enable those skilled in the art to implement or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but is consistent with the widest scope of the principles and novel features disclosed herein.

Claims

1. An apparatus for passive wireless communication, the apparatus comprising: One or more processors; and Memory, which can be accessed by the one or more processors, wherein the one or more processors are configured to: Transmit information indicating the power preference of the device to the first network node; Receive radio frequency (RF) signals from the first network node, wherein the RF signals are based on the information; and Based on the backscatter modulation of the RF signal, data is transmitted to one or more of the first network node or the second network node.

2. The apparatus of claim 1, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

3. The apparatus of claim 1, wherein the information indicating the power preference includes a ratio between a first power obtainable from the RF signal and a second power of the backscatter modulation of the RF signal.

4. The apparatus of claim 1, wherein the one or more processors are further configured to: Measure the power of the RF signal; and The first network node is sent information indicating a request to increase or decrease the power of subsequent RF signals.

5. The apparatus of claim 1, wherein the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or periodicity for signal transmission within the signal time window.

6. The apparatus of claim 1, wherein the first network node is a reader.

7. The apparatus of claim 6, wherein the reader is one or more of a user equipment (UE) or a base station.

8. The apparatus of claim 1, wherein the RF signal is a continuous wave.

9. The apparatus of claim 1, wherein the apparatus is a passive or semi-passive backscattering device.

10. A network node for passive wireless communication, the network node comprising: One or more processors; and Memory, which can be accessed by the one or more processors, wherein the one or more processors are configured to: Receive information indicating the power preference of the backscattering device from the backscattering device; A radio frequency (RF) signal is transmitted to the backscattering device, wherein the RF signal is based on the information; as well as Data is received from the backscattering device based on the backscattering modulation of the RF signal by the backscattering device.

11. The network node of claim 10, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

12. The network node of claim 10, wherein the information indicating the power preference includes a ratio between a first power obtainable from the RF signal and a second power of the backscatter modulation of the RF signal.

13. The network node of claim 10, wherein the one or more processors are further configured to: The available power of the RF signal at the backscattering device is estimated based on the received power of the backscatter modulation of the RF signal and the information indicating the power preference.

14. The network node of claim 13, wherein the one or more processors are further configured to: The transmission power of the RF signal is determined based on the available power of the RF signal at the backscattering device and based on the target power.

15. The network node of claim 10, wherein the one or more processors are further configured to: Receive information from the backscattering device indicating a request to increase or decrease the power of subsequent RF signals; and The subsequent RF signal is transmitted to the backscattering device based on the request.

16. The network node of claim 10, wherein the information indicating the power preference includes one or more of the following: a preferred minimum periodicity for receiving subsequent RF signals, a signal time window per cycle for receiving the subsequent RF signals, or periodicity for signal transmission within the signal time window; and wherein the one or more processors are configured to: Based on the information, one or more subsequent RF signals are transmitted to the backscattering device.

17. The network node of claim 10, wherein the network node is a first network node, and wherein the one or more processors are further configured to: Configuration information is received from one or more second network nodes, the configuration information including information indicating the power preference of the backscattering device.

18. The network node of claim 17, wherein the information indicating the power preference of the backscattering device includes one or more of discontinuous reception (DRX) configuration, duration, frequency resources, or the location of the backscattering device.

19. The network node of claim 18, wherein the one or more processors are further configured to: Based on the location of the backscattering device, it is determined that the first network node is located near the backscattering device; and The first network node sends the RF signal to the backscattering device because it is located near the backscattering device.

20. The network node of claim 10, wherein the network node is a reader.

21. The network node of claim 20, wherein the reader is one or more of a user equipment (UE) or a base station.

22. The network node of claim 10, wherein the RF signal is a continuous wave.

23. The network node of claim 10, wherein the backscattering device is a passive or semi-passive backscattering device.

24. A method for passive wireless communication using a backscattering device, the method comprising: Transmit information indicating the power preference of the backscattering device to the first network node; Receive radio frequency (RF) signals from the first network node, wherein the RF signals are based on the information; and Based on the backscatter modulation of the RF signal, data is transmitted to one or more of the first network node or the second network node.

25. The method of claim 24, wherein the information indicating the power preference includes one or more of the supported modulation type, the number of impedance states, or the power reflection coefficient.

26. The method of claim 24, wherein the information indicating the power preference includes a ratio between a first power obtainable from the RF signal and a second power of the backscatter modulation of the RF signal.

27. A method for passive wireless communication, the method comprising: Receive information indicating the power preference of the backscattering device from the backscattering device; A radio frequency (RF) signal is transmitted to the backscattering device, wherein the RF signal is based on the information; as well as Data is received from the backscattering device based on the backscattering modulation of the RF signal by the backscattering device.

28. The method of claim 27, further comprising: The available power of the RF signal at the backscattering device is estimated based on the received power of the backscatter modulation of the RF signal and the information indicating the power preference.

29. The method according to claim 28, further comprising: The transmission power of the RF signal is determined based on the available power of the RF signal at the backscattering device and based on the target power.

30. The method of claim 27, further comprising: Receive information from the backscattering device indicating a request to increase or decrease the power of subsequent RF signals; as well as The subsequent RF signal is transmitted to the backscattering device based on the request.

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