Methods, architectures, apparatuses, and systems for multiplexing backscatter

Abstract

Methods, architectures, apparatuses, and systems directed to multiplexed backscatter are described herein. In one embodiment, a transmit / receive unit (WTRU) can receive first information indicating a first time offset with respect to a first reference signal transmission. The WTRU can receive the first reference signal transmission and a second reference signal transmission. The WTRU can transmit a third reference signal transmission at the indicated first time offset with respect to the first reference signal transmission based on the received second reference signal transmission, the third reference signal transmission being transmitted in response to a power condition being satisfied.

Description

[0001] Cross-references to related applications This application claims the benefit of U.S. Patent Application No. 63 / 619,619, filed January 10, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure is generally directed to the fields of communications, software, and coding, including methods, architectures, apparatus, and systems for multiplexing backscatter. Background Technology

[0003] In 3GPP Release 16, downlink, uplink, and downlink-uplink positioning methods can be used. In 3GPP, devices such as ambient Internet of Things (IoT) devices can transmit via backscatter, potentially causing collisions at the base station. The embodiments described herein have been designed with these considerations in mind. Summary of the Invention

[0004] This document describes methods, architectures, apparatuses, and systems for multiplexing backscatter. In one embodiment, a method implemented in a wireless transmit / receive unit (WTRU) is described. The method may include receiving first information indicating a first time offset with respect to a first reference signal transmission. The method may include receiving the first reference signal transmission and, for example, determining whether the received first reference signal transmission satisfies a power condition. The method may include receiving a second reference signal transmission and transmitting a third reference signal transmission based on (1) the received second reference signal transmission, (2) the indicated first time offset, and (3) whether the received first reference signal transmission satisfies a power condition. In one example, the third reference signal transmission may be transmitted based on the received second reference signal transmission at the indicated first time offset with respect to the first reference signal transmission. In various embodiments, the third reference signal transmission may be transmitted in response to a power condition being satisfied.

[0005] In one embodiment, a WTRU including circuitry is described, the circuitry comprising any one of a transmitter, a receiver, a processor, and a memory. The WTRU may be configured to receive first information indicating a first time offset with respect to a first reference signal transmission. The WTRU may be configured to receive the first reference signal transmission and, for example, determine whether the received first reference signal transmission satisfies a power condition. The WTRU may be configured to receive a second reference signal transmission and transmit a third reference signal transmission based on (1) the received second reference signal transmission, (2) the indicated first time offset, and (3) whether the received first reference signal transmission satisfies a power condition. In one example, the third reference signal transmission may be transmitted based on the received second reference signal transmission at the indicated first time offset with respect to the first reference signal transmission. In various embodiments, the third reference signal transmission may be transmitted in response to a power condition being satisfied.

[0006] In one embodiment, a method implemented in a network element is described. The method may include transmitting first information to a first WTRU. In various embodiments, the first information may indicate a first time offset of a first reference signal transmission among a plurality of reference signal transmissions. The method may include transmitting second information to a second WTRU. In various embodiments, the second information may indicate a second time offset of the first reference signal transmission, and the first time offset may be different from the second time offset. The method may include transmitting the plurality of reference signal transmissions. The method may include receiving from the first WTRU a second reference signal transmission at the first time offset of the first reference signal transmission, and receiving from the second WTRU a third reference signal transmission at the second time offset of the first reference signal transmission.

[0007] In one embodiment, a network element including circuitry comprising any one of a transmitter, a receiver, a processor, and a memory is described. The network element can be configured to transmit first information to a first WTRU. In various embodiments, the first information may indicate a first time offset regarding a first reference signal transmission among a plurality of reference signal transmissions. The network element can be configured to transmit second information to a second WTRU. In various embodiments, the second information may indicate a second time offset regarding the first reference signal transmission, and the first time offset may differ from the second time offset. The network element can be configured to transmit the plurality of reference signal transmissions. The network element can be configured to receive from the first WTRU a second reference signal transmission at a first time offset regarding the first reference signal transmission, and from the second WTRU a third reference signal transmission at a second time offset regarding the first reference signal transmission. Attached Figure Description

[0008] A more detailed understanding can be obtained from the following detailed description given by way of example in conjunction with the accompanying drawings. Like this detailed description, the figures in such drawings are exemplary. Therefore, the figures (each) and the detailed description should not be considered limiting, and other equally valid examples are possible and likely to occur. Furthermore, similar reference numerals (ref) in the figures indicate similar elements, and wherein: Figure 1A This is a system diagram illustrating an example communication system.

[0009] Figure 1B It's shown in the diagram. Figure 1A The diagram shows a system diagram of an example wireless transmit / receive unit (WTRU) used in a communication system.

[0010] Figure 1C It's shown in the diagram. Figure 1A The diagram illustrates a system diagram of an example radio access network (RAN) and an example core network (CN) used within a communication system.

[0011] Figure 1D It's shown in the diagram. Figure 1A The diagram shows another example RAN and another example CN used in the communication system.

[0012] Figure 2 This is a diagram illustrating the transmission of a Position Reference Signal (PRS). Figure 3 This is a diagram illustrating an example transmission timeline at the Transmit and Receive Points (TRPs); Figure 4 This is a diagram illustrating an example timeline used for transmitting the reference PRS and measuring the PRS; Figure 5 This is a diagram illustrating another example timeline used for transmitting the reference PRS and measuring the PRS; Figure 6 This is a timeline diagram illustrating an example. Figure 7 This is a diagram illustrating example signaling from the network; Figure 8 This is a diagram illustrating an example timeline of PRS transmissions from the network; Figure 9 This is a diagram illustrating an example of more than one message arranged in a time-division multiplexing manner; Figure 10 This is a diagram illustrating an example of more than one message arranged in a frequency division multiplexing manner; Figure 11 This is a diagram illustrating an example protocol exchange between a WTRU and the network; Figure 12This is a diagram illustrating an example timeline used for transmitting the reference PRS and measuring the PRS; Figure 13 This is a diagram illustrating an example timeline of timing offsets; Figure 14 This is a diagram illustrating an example time slot structure of a WTRU; Figure 15 This is a diagram illustrating an example of WTRU Tx silent mode; Figure 16 This is a diagram illustrating an example of a WTRU Tx silent mode with repeating granularity; Figure 17 This is a diagram illustrating an example of a WTRU Tx silent mode with repeating group granularity; Figure 18 This is a diagram illustrating an example of a WTRU Tx silent mode with repeating group granularity and a reference PRS; Figure 19 This is a diagram illustrating an example of a configured transmission filter for a WTRU; Figure 20 This is a diagram illustrating an example of backscattering based on frequency domain multiplexing (FDM); Figure 21 This is a diagram illustrating an example configuration of timing offset and frequency hopping mode; Figure 22 This is a diagram illustrating an example of backscattering with frequency hopping and time shifting; Figure 23 This is a diagram illustrating an example method for multiplexing backscatter implemented in WTRU; Figure 24 This is a diagram illustrating another example method for multiplexing backscatter implemented in WTRU; Figure 25 This is a diagram illustrating an example method for multiplexing backscattering implemented in network elements; Figure 26 This is a diagram illustrating an example method for backscattering in the presence of multipath, implemented in WTRU; and Figure 27 This is a diagram illustrating an example method for backscattering in the presence of multipath, implemented in network elements. Detailed Implementation

[0013] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the description below. Furthermore, embodiments and examples not specifically described herein may be practiced in place of or in combination with the embodiments and other examples described, disclosed, or otherwise explicitly, implicitly, and / or inherently provided (collectively, the “Provided”). Although various embodiments are described and / or claimed herein, in which apparatuses, systems, devices, etc., and / or any elements thereof perform operations, processes, algorithms, functions, etc., and / or any part thereof, it is to be understood that any embodiment described and / or claimed herein assumes that any apparatus, system, device, etc., and / or any element thereof is configured to perform any operation, process, algorithm, function, etc., and / or any part thereof.

[0014] Example Communication System The methods, apparatus, and systems provided herein are well-suited for communications involving both wired and wireless networks. Regarding Figure 1A-1D An overview of various types of wireless devices and infrastructures is provided, wherein various elements of the network may be utilized, performed, arranged, and / or adapted and / or configured for use with the methods, apparatuses, and systems provided herein.

[0015] Figure 1A This is a system diagram illustrating an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, and broadcasting to multiple wireless users. The communication system 100 enables multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tail (ZT) Unique Word (UW) Discrete Fourier Transform (DFT) Spread Spectrum OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multicarrier (FBMC), and so on.

[0016] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, radio access networks (RANs) 104 / 113, core networks (CNs) 106 / 115, public switched telephone networks (PSTNs) 108, the Internet 110, and other networks 112. However, it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d can be any type of device configured to operate and / or communicate in a wireless environment. For example, WTRUs 102a, 102b, 102c, and 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include (or be) user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, and so on. Any of WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0017] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a and 114b can be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d, for example, to facilitate access to one or more communication networks, such as CN 106 / 115, Internet 110, and / or Network 112. For example, base stations 114a and 114b can be any of a base transceiver station (BTS), Node-B (NB), eNode-B (eNB), home Node-B (HNB), home eNode-B (HeNB), gNode-B (gNB), New Radio (NR) Node-B (NR NB), site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are each depicted as a single element, it will be understood that base stations 114a and 114b can include any number of interconnected base station and / or network elements.

[0018] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector or any sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0019] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116. Air interface 116 can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) can be used to establish air interface 116.

[0020] More specifically, as described above, the communication system 100 can be a multi-access system and can employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish an air interface 116 using Wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0021] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as evolved UMTS terrestrial radio access (E-UTRA), which may use Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish air interface 116.

[0022] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can use New Radio (NR) to establish air interface 116.

[0023] In one embodiment, base station 114a and WTRUs 102a, 102b, and 102c can implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c can jointly implement LTE radio access and NR radio access, for example, using the dual connectivity (DC) principle. Therefore, the air interface used by WTRUs 102a, 102b, and 102c can be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0024] In one embodiment, base station 114a and WTRUs 102a, 102b, and 102c can implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), GSM EDGE (GERAN), and so on.

[0025] For example, Figure 1ABase station 114b can be a wireless router, home Node-B, home eNode-B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in localized areas, such as commercial locations, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for drone use), roads, etc. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In one embodiment, base station 114b and WTRUs 102c, 102d can utilize cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish any of the following: small cells, picocells, or femtocells. Figure 1A As shown, base station 114b can be directly connected to the Internet 110. Therefore, base station 114b may not need to access the Internet 110 via CN 106 / 115.

[0026] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. Data can have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although in Figure 1A As not shown, but to be understood, RAN104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs employing the same RAT as or a different RAT than RAN 104 / 113. For example, in addition to being connected to RAN 104 / 113, which may utilize NR radio technology, CN106 / 115 can also communicate with another RAN (not shown) employing any of GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technologies.

[0027] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 114 or a different RAT.

[0028] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example... Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which may employ cellular-based radio technology, and with base station 114b, which may employ IEEE 802 radio technology.

[0029] Figure 1B This is a system diagram illustrating example WTRU 102. (Example:) Figure 1B As shown, among other things, WTRU 102 may include, in particular, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other components / peripherals 138. It will be understood that WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0030] Processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, which may be coupled to transmitting / receiving element 122. Although Figure 1B The processor 118 and transceiver 120 are depicted as separate components, but it will be understood that the processor 118 and transceiver 120 may be integrated together in, for example, an electronic package or chip.

[0031] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) on air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. In one embodiment, transmitting / receiving element 122 can be, for example, a transmitter / detector configured to transmit and / or receive IR, UV, or visible light signals. In one embodiment, transmitting / receiving element 122 can be configured to transmit and / or receive both RF and optical signals. It will be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0032] Although the transmitting / receiving element 122 is in Figure 1B While depicted as a single element, WTRU 102 may include any number of transmit / receive elements 122. For example, WTRU 102 may employ MIMO technology. Therefore, in one embodiment, WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals on air interface 116.

[0033] Transceiver 120 can be configured to modulate signals transmitted by transmitting / receiving element 122 and demodulate signals received by transmitting / receiving element 122. As described above, WTRU 102 can have multi-mode capability. Thus, for example, transceiver 120 can include multiple transceivers to enable WTRU 102 to communicate via multiple RATs such as NR and IEEE 802.11.

[0034] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data therefrom. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. Furthermore, the processor 118 can access and store information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 may include a user identification module (SIM) card, memory stick, secure digital storage (SD) card, etc. In other embodiments, the processor 118 can access and store information from memory that is not physically located on WTRU 102, such as a server or home computer (not shown).

[0035] The processor 118 can receive power from the power supply 134 and can be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 can be any suitable device that powers the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0036] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information on the air interface 116 from base stations (e.g., base stations 114a, 114b), and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may acquire location information using any suitable location determination method while remaining consistent with the embodiments.

[0037] Processor 118 may be further coupled to other components / peripherals 138, which may include one or more software and / or hardware modules / units providing additional features, functions, and / or wired or wireless connectivity. For example, components / peripherals 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (e.g., for photos and / or video), Universal Serial Bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, FM radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, and so on. Components / peripherals 138 may include one or more sensors, such as gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, attitude sensors, biosensors, and / or humidity sensors.

[0038] WTRU 102 may include a full-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for both uplink (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., chokes) or via signal processing by a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio for which the transmission and reception of some or all signals (e.g., signals associated with specific subframes for either uplink (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0039] Figure 1C The diagram illustrates a system diagram of RAN 104 and CN 106 according to an embodiment. As noted above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0040] RAN 104 may include eNode-Bs 160a, 160b, and 160c; however, it will be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiments. eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, for example, eNode-B 160a may use multiple antennas to transmit and receive radio signals from WTRU 102a.

[0041] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in the uplink (UL) and / or downlink (DL), etc. Figure 1C As shown, eNode-B 160a, 160b, and 160c can communicate with each other on the X2 interface.

[0042] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (PGW) 166. While each of the foregoing elements is described as part of CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0043] The MME 162 can connect to each of the eNode-Bs 160a, 160b, and 160c in RAN 104 via the S1 interface and can act as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0044] The SGW 164 can connect to each of the eNode-Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can typically route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can perform other functions such as anchoring the user plane during inter-eNode-B handover, triggering paging when DL data is available for WTRUs 102a, 102b, and 102c, managing and storing the context of WTRUs 102a, 102b, and 102c, etc.

[0045] SGW 164 can connect to PGW 166, which can provide WTRU 102a, 102b, 102c with access to packet-switched networks such as Internet 110, so as to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0046] CN 106 can facilitate communication with other networks. For example, CN 106 can provide WTRU 102a, 102b, and 102c with access to a circuit-switched network such as PSTN 108, facilitating communication between WTRU 102a, 102b, and 102c and traditional landline communication equipment. For example, CN 106 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 106 and PSTN 108. Furthermore, CN 106 can provide WTRU 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0047] Despite WTRU in Figure 1A-1D While described as a wireless terminal, it is conceivable that, in some representative embodiments, such a terminal may use (e.g., temporarily or permanently) a wired communication interface with a communication network.

[0048] In a representative embodiment, another network 112 may be a WLAN.

[0049] A WLAN in Infrastructure Basic Services Set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can access or interface with a distributed system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic originating outside the BSS destined for a STA can reach and be delivered to the STA via the AP. Traffic originating from a STA destined for an external BSS can be sent to the AP for delivery to the appropriate destination. For example, traffic between STAs within the BSS can be sent via the AP, where the source STA can send traffic to the AP, and the AP can deliver traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between source and destination STAs (e.g., directly between them) using Direct Link Establishment (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z Tunneled DLS (TDLS). WLANs using Standalone BSS (IBSS) mode may not have access points (APs), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. IBSS communication mode is sometimes referred to as "ad-hoc" communication mode in this document.

[0050] When using 802.11ac infrastructure operating mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of a fixed width (e.g., a 20 MHz bandwidth) or dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, such as in an 802.11 system, Carrier Sense Multiple Access (CSMA / CA) with collision avoidance can be implemented. For CSMA / CA, each STA, including the AP, can sense the primary channel. If a particular STA senses / detects and / or determines that the primary channel is busy, that particular STA can back off. A single STA (e.g., only one station) can transmit at any given time within a given BSS.

[0051] High-throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, by combining a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels.

[0052] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels, which can be referred to as an 80+80 configuration. For the 80+80 configuration, after channel coding, the data passes through a segment resolver, which splits the data into two streams. Each stream can be processed separately using Inverse Fast Fourier Transform (IFFT) and time-domain processing. The streams can be mapped onto two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC) layer, entities, etc.

[0053] 802.11af and 802.11ah support operating modes below 1 GHz. The channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV whitespace (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support metering-type control / machine-type communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only) certain and / or limited bandwidths. MTC devices may include batteries with a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0054] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as the primary channel. The bandwidth of the primary channel can be equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by the STA among all STAs operating in the BSS that supports the minimum bandwidth operating mode. In the example of 802.11ah, for a STA that supports (e.g., only supports) the 1 MHz mode (e.g., an MTC type device), the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier Sense and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, because an STA (which only supports the 1 MHz operating mode) is transmitting to the AP, the entire available band can be considered busy, even if most of the band remains idle and can be available.

[0055] In the United States, the available frequency band for 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0056] Figure 1D This diagram illustrates a system diagram of RAN 113 and CN 115 according to one embodiment. As described above, RAN 113 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using NR radio technology. RAN 113 can also communicate with CN 115.

[0057] RAN 113 may include gNBs 180a, 180b, and 180c; however, it will be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c on air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from WTRUs 102a, 102b, and 102c. Thus, for example, gNB 180a may use multiple antennas to transmit and / or receive radio signals from WTRU 102a. In one embodiment, gNBs 180a, 180b, and 180c can implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers (not shown) to WTRU 102a. A subset of these component carriers can be on unlicensed spectrum, while the remaining component carriers can be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c can implement Coordinated Multipoint (CoMP) technology. For example, WTRU 102a can receive coordinated transmissions from gNBs 180a and 180b (and / or gNB 180c).

[0058] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with scalable digitization. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing can differ for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various or scalable lengths (e.g., including a variable number of OFDM symbols and / or a continuously variable absolute time).

[0059] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can utilize one or more of gNBs 180a, 180b, and 180c as mobility anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using signals in unlicensed frequency bands. In a non-standalone configuration, WTRUs 102a, 102b, and 102c can communicate / connect with gNBs 180a, 180b, and 180c, while also communicating / connecting with another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c can implement DC principles to communicate substantially simultaneously with one or more gNBs 180a, 180b, and 180c, as well as one or more eNode-Bs 160a, 160b, and 160c. In a non-standalone configuration, eNode-Bs 160a, 160b, and 160c can act as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0060] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing user plane data to User Plane Functions (UPF) 184a and 184b, routing control plane information to Access and Mobility Management Functions (AMF) 182a and 182b, and so on. Figure 1D As shown, gNB 180a, 180b, and 180c can communicate with each other on the Xn interface.

[0061] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and at least one Data Network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0062] AMF 182a and 182b can connect to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different Protocol Data Unit (PDU) sessions with different requirements), selecting specific SMF 183a and 183b, managing registration areas, terminating Non-Access Stratum (NAS) signaling, mobility management, and so on. AMF 182a and 182b can use network slicing, for example, to customize CN support for WTRU 102a, 102b, and 102c based on the service types utilized by WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services relying on Ultra Reliable Low Latency Time (URLLC) access, services relying on Enhanced Massive Mobile Broadband (eMBB) access, services for MTC access, and / or so on. AMF 182a, 182b can provide control plane functions for handover between RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as Wi-Fi.

[0063] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b, and configure the routing of services through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0064] UPF 184a and 184b can be connected to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N3 interface. This N3 interface can provide WTRU 102a, 102b, and 102c with access to packet-switched networks (such as Internet 110), for example, to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices. UPF 184a and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and so on.

[0065] CN 115 can facilitate communication with other networks. For example, CN 115 may include, or be able to communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108. Furthermore, CN 115 can provide WTRUs 102a, 102b, and 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, and 102c may be connected to the local data network (DN) 185a and 185b via the N3 interface to UPFs 184a and 184b and the N6 interface between UPFs 184a and 184b and DNs 185a and 185b.

[0066] Given Figure 1A-1D as well as Figure 1A-1D As described herein, one or more, or all, of the functions described in any of the following can be performed by one or more emulation components / devices (not shown): WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or one or more other components / devices described herein. An emulation device can be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, an emulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0067] Simulation devices can be designed to perform tests on one or more other devices in laboratory and / or carrier network environments. For example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0068] One or more simulation devices may perform one or more functions, including all functions, rather than being implemented / deployed as part of a wired and / or wireless communication network. For example, simulation devices may be used to test test scenarios in laboratory and / or non-deployment (e.g., testing) wired and / or wireless communication networks to implement the testing of one or more components. One or more simulation devices may be test devices. Simulation devices may transmit and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas).

[0069] Throughout the embodiments described herein, the terms “base station,” “network,” and “gNB” (collectively referred to as “network”) may be used interchangeably to designate any network element, such as a network element used as a serving base station, for example. The embodiments described herein are not limited to gNBs and are applicable to any other type of base station.

[0070] For clarity, throughout the embodiments described herein, satisfied and unsatisfied conditions, as well as configuration(s) condition(s) parameters, are described as relating to threshold (e.g., greater than or less than) values, configuration (e.g., threshold) values, etc. For example, satisfied conditions may be described as being higher than (e.g., threshold) values, and unsatisfied conditions may be described as being lower than (e.g., threshold) values. The embodiments described herein are not limited to threshold-based conditions. Any other kind of conditions and(s) parameters (such as, for example, belonging to or not belonging to a value range) may be applied to the embodiments described herein.

[0071] Throughout the embodiments described herein, (e.g., configuration) information can be described as being received by the WTRU from the network, for example, via system information or via any kind of protocol message. Although not explicitly mentioned throughout the embodiments described herein, the same (e.g., configuration) information can be pre-configured in the WTRU (e.g., via any kind of pre-configuration method, such as, for example, via factory settings) so that the (e.g., configuration) information can be used by the WTRU without being received from the network.

[0072] Throughout the embodiments described herein, the statement "WTRU can be configured with a set of parameters" is equivalent to "WTRU can receive (e.g., configuration information indicating a set of parameters from another network element (e.g., gNB)" or can be used interchangeably therewith. Throughout the embodiments described herein, the statements "WTRU can report something," "WTRU can be configured to report something," and "WTRU can send (indicate) a report of something" are equivalent to "WTRU can transmit (e.g., report) information indicating something" or can be used interchangeably therewith.

[0073] Throughout the embodiments described herein, the statements “WTRU can signal parameters” and “WTRU can indicate parameters” are equivalent to “WTRU can receive (e.g., from another network element (e.g., gNB)) information indicating parameters” or can be used interchangeably.

[0074] Throughout the embodiments described herein, the statement “WTRU may be instructed to perform an action” is equivalent to “WTRU may receive (e.g., from another network element (e.g., gNB)) information instructing to perform an action” or may be used interchangeably with it.

[0075] In the embodiments described herein, “a” and “an” and similar expressions should be interpreted as “one or more” and “at least one”. Similarly, any term ending with the suffix “(s)” should be interpreted as “one or more” and “at least one”. The term “may” should be interpreted as “for example, may”.

[0076] The symbol “ / ” (e.g., a forward slash) can be used in this article to mean “and / or”, for example, where “A / B” can imply “A and / or B”.

[0077] In the embodiments described herein, “a list of…”, “a set of…”, and “one or more of…” can be used interchangeably.

[0078] In the embodiments described herein, “identity” and “identifier” may be used interchangeably to refer to how a network element (or WTRU) can be identified.

[0079] In the embodiments described herein, network element can refer to any kind of device that can be connected to a network, including computing resources and networking capabilities. The terms network element and node are used interchangeably. A network element can be any kind of network infrastructure device and / or WTRU. Figure 1B The architecture described for WTRU 102 can be more generally applied to any kind of network element.

[0080] Positioning method In 3GPP Release 16, downlink, uplink, and downlink and uplink positioning methods can be used.

[0081] In the embodiments described herein, any of the DL positioning method, the UL positioning method, or both DL and UL positioning methods may be applied.

[0082] DL positioning method can refer to any positioning method that can use downlink reference signals, such as, for example, positioning reference signals (PRS). A WTRU can receive multiple reference signals from a transmission point ((one or more) TP) and can measure the DL reference signal time difference (RSTD) and / or reference signal received power (RSRP). Examples of DL positioning methods can include either downlink departure angle (DL-AoD) or downlink arrival time difference (DL-TDOA) positioning.

[0083] UL positioning method can refer to any positioning method that can use an uplink reference signal, such as a sounding reference signal (SRS) for positioning, for example. The WTRU can transmit the SRS to multiple receiving points (RPs), and the RPs can measure the UL relative time of arrival (RTOA) and / or RSRP. Examples of UL positioning methods can include either UL-TDOA or uplink angle of arrival (UL-AoA) positioning.

[0084] DL and UL positioning methods can refer to any positioning method that uses uplink and downlink reference signals for positioning. In one example, the WTRU can transmit SRS to multiple TRPs, and the gNB can measure the Rx-Tx time difference, which can be calculated based on the arrival time of the DL RS (e.g., PRS). The gNB can measure the RSRP of the received SRS. The WTRU can measure the Rx-Tx time difference of the PRS transmitted from multiple TRPs. The WTRU can measure the RSRP of the received PRS. The Rx-Tx difference measured at the WTRU and gNB, along with, for example, the RSRP, can be used to calculate the round-trip time. In the embodiments described herein, the WTRU Rx-Tx time difference refers to the difference between the arrival time of the reference signal transmitted by the TRP and the transmission time of the reference signal transmitted from the WTRU. An example of DL and UL positioning methods could be multi-round-trip time (RTT) positioning.

[0085] In 3GPP, a WTRU (WTR that can include an environmental IoT device) can transmit data via backscatter (e.g., backscatter only). For RTT-based positioning, the WTRU (e.g., an environmental IoT device) can transmit the received DL RS (e.g., PRS).

[0086] If multiple environmental IoT devices deployed in the field attempt to reflect the received PRS simultaneously, collisions of the RS transmitted by the WTRU may occur at the gNB. The embodiments described herein allow for the avoidance of collisions between backscattered signals from different WTRUs.

[0087] Overview of Time-Domain Offset-Based Signal Transmission The WTRU can receive configuration information from the network indicating a timing offset at which the WTRU can be expected to perform backscattering. After the WTRU has determined that it may have received a reference DL-RS, it can start a timer. After a certain amount of time corresponding to (e.g., the configured) timing offset has elapsed (e.g., when the timer reaches the configured timing offset), the WTRU can transmit the received DL-RS, which can be transmitted periodically. If the WTRU is unable to transmit the received DL-RS at the configured timing offset, for example, based on insufficient (e.g., lack of) harvested power, the WTRU can determine at the next transmission opportunity, for example, based on the fact that the WTRU can harvest power that meets a power condition (e.g., above a pre-configured threshold).

[0088] In one example, the WTRU (e.g., environmental IoT) can be configured via the network with any of the following: a reference PRS sequence (e.g., pseudo-noise (PN) sequence identifier (ID)), a PRS period (e.g., 2 milliseconds), and the number of PRS timings per cycle (e.g., four). In one example, the reference PRS can be transmitted (e.g., only) at the reference timing.

[0089] In one example, the WTRU can receive from the network a message (e.g., including information) indicating the time offset (e.g., the number of times T after the reference PRS Rx) regarding the timing of the reference PRS Rx. The message may indicate when the WTRU can expect to receive the first PRS after the message (e.g., expected Tx).

[0090] In one example, the WTRU can receive a signal (e.g., if the RSRP is above a threshold) and determine whether the received signal is a reference PRS (e.g., a sequence). If the received reference signal is not a reference PRS, the WTRU can continue searching (e.g., monitoring for a reference PRS) until the WTRU can find (e.g., receive) a reference PRS (e.g., a sequence).

[0091] In one example, based on the reference PRS satisfying a power condition (e.g., RSRP is above a threshold), the WTRU can transmit (e.g., backscatter) the received PRS (which may differ from the reference PRS) at an indicated timing offset relative to the reference PRS (e.g., an indicated number of T timings after the reference PRS). If the WTRU cannot transmit at the indicated timing offset (e.g., based on a lack of (e.g., based on insufficient) Tx power), the WTRU can (e.g., determine) transmit at the next transmission timing (e.g., an indicated number of T timings after the reference PRS).

[0092] In one example, after the WTRU may receive a termination message from the network (e.g., indicating termination of the positioning method), the WTRU may decide not to transmit.

[0093] WTRU Behavior Overview In one example, the WTRU may send a request to the network for configuration (e.g., any of the PRS configuration or SRSp configuration) in any of the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Uplink Control Information (UCI), MAC Control Element (MAC-CE), Radio Resource Control (RRC) messages, or LTE Positioning Protocol (LPP) messages. The request from the WTRU may include information indicating one or more configurations of any of the measurement gaps, PRS processing windows, and windows for transmitting SRS (SRSp) for positioning.

[0094] In one example, WTRU can receive authorization information from the network.

[0095] In one example, WTRU can send an acknowledgment message for authorization information received from the network in either PUSCH or PUCCH.

[0096] In one example, one or more conditions (e.g., criteria) can be used in combination. A WTRU can be configured with one or more conditions and associated WTRU behaviors. The WTRU can determine which behavior to use based on the applicable conditions.

[0097] In one example, the WTRU can measure DL-PRS both inside and / or outside the active bandwidth portion (BWP). The WTRU can transmit SRSp both inside and / or outside the active BWP.

[0098] In one example, the WTRU is pre-configured with parameters (e.g., one or more measurement gaps, one or more PRS processing windows, one or more PRS configurations, one or more SRSp configurations) via (e.g., based on reception) semi-static messages (e.g., via any of LPP or RRC).

[0099] In one example, the WTRU can determine any action that can be taken by the network. For instance, the WTRU can be configured with rules associated with actions, and based on those rules, the WTRU can determine to take (e.g., execute) the associated action.

[0100] In one example, in addition to the measurements performed on the PRS, the WTRU may also include (for example, performing) one or more cell-related measurements, such as the Synchronization Signal Block (SSB) RSRP and corresponding cell ID from the serving cell, the SSB RSRP and corresponding cell ID from (one or more) neighboring cells, the RSRP and CSI-RS resource ID of the Channel State Information Reference Signal (CSI-RS), and the RSRP of the Demodulation Reference Signal (DM-RS).

[0101] the term In the embodiments described herein, "network" may include any one of an AMF network element, a Location Management Function (LMF) network element, a gNB, and a Next Generation Radio Access Network (NG-RAN) network element.

[0102] In the embodiments described herein, the terms "message" and "information" may be used interchangeably.

[0103] In the embodiments described herein, the terms “pre-configured” and “configured” may be used interchangeably.

[0104] In the embodiments described herein, the terms "non-serving gNB" and "neighboring gNB" may be used interchangeably.

[0105] In the embodiments described herein, the terms “gNB” and “TRP” may be used interchangeably.

[0106] In the embodiments described herein, the terms “PRS”, “SRS”, “SRS for positioning” and “SRS for positioning purposes” are used interchangeably.

[0107] In the embodiments described herein, the terms “PRS” and “PRS resource” are used interchangeably.

[0108] In the embodiments described herein, the terms "(one or more) PRS" and "(one or more) PRS resources" are used interchangeably. The aforementioned "(one or more) PRS" or "(one or more) PRS resources" may belong to different sets of PRS resources.

[0109] In the embodiments described herein, the terms “PRS”, “PRS transmission”, “DL-PRS”, and “DL PRS” may be used interchangeably.

[0110] In the embodiments described herein, the terms "reference signal" and "reference signal transmission" may be used interchangeably.

[0111] In the embodiments described herein, the terms "measurement gap" and "measurement gap mode" are used interchangeably. A measurement gap mode may include one or more parameters (e.g., may be associated with said one or more parameters), such as, for example, any one of measurement gap duration, measurement gap repetition period, and measurement gap periodicity.

[0112] In the embodiments described herein, the Positioning Reference Unit (PRU) can be a WTRU or TRP whose location (e.g., any of altitude, latitude, geographic coordinates, or local coordinates) is known to the network (e.g., any of gNB, LMF). The capabilities of the PRU can be the same as those of the WTRU or TRP, such as being able to receive PRS, transmit SRS (or SRS for positioning), report measurements, and transmit PRS. The WTRU acting as a PRU can be used by the network for calibration purposes (e.g., correcting for unknown timing offsets, correcting for unknown angular offsets).

[0113] In the embodiments described herein, the terms “time offset with respect to an event” and “timing offset with respect to an event” may be used interchangeably and may be expressed as the number T of one or more opportunities following the event, wherein the one or more opportunities represent transmission opportunities, such as for transmitting a reflected (e.g., received) reference signal.

[0114] An LMF network element can be a non-limiting example of a network element that can be used to or support positioning. Any other network element can be used in place of an LMF and can be adapted to the embodiments described herein.

[0115] In one example, the WTRU may receive configuration information indicating one or more pre-configured thresholds from a network (e.g., any of the LMF or gNB) according to any of the embodiments described herein.

[0116] A line-of-sight (LOS) indicator can be a hard indicator (e.g., one or zero) or a soft indicator (e.g., any value between zero and one, such as 0, 0.1, 0.2, ..., 1). The LOS indicator can indicate the likelihood (e.g., probability) of a LOS path existing between the TRP and the WTRU or along the PRS. The LOS indicator can be associated with either the TRP or the PRS resource ID (e.g., an index). In one example, the WTRU can receive information from the network indicating the LOS indicator per TRP and per resource ID. In another example, the WTRU can determine the LOS indicator based on measurements per TRP and per resource ID.

[0117] For example, WTRU location can be expressed in terms of altitude, latitude, geographic coordinates, and local coordinates.

[0118] For clarity, embodiments are described herein using a Positioning Reference Signal (PRS). Any other type of reference signal is applicable to the embodiments described herein.

[0119] Configuration for RS positioning This article describes the configuration for RS positioning.

[0120] Configuration for PRS In one example, information indicating PRS configuration may include (e.g., indicating) the number of symbols, transmission power, number of PRS resources included in the PRS resource set, PRS silence mode (e.g., silence mode may be expressed via a bitmap), period, PRS type (e.g., any one of periodic, semi-persistent, and aperiodic), slot offset for periodic PRS transmission, vertical shift of the PRS mode in the frequency domain, time interval during repetition, repetition factor, resource element (RE) offset, comb pattern, comb size, spatial relationship, quasi-co-location (QCL) information for PRS (e.g., any one of QCL target and QCL source), number of PRUs, number of TRPs, absolute radio channel number (ARFCN), subcarrier spacing, expected RSTD, uncertainty of expected RSTD, starting physical resource block (PRB), bandwidth, BWP ID, number of frequency layers, start / end time of PRS transmission, PRS on / off indicator, TRP ID, PRS ID, cell ID, global cell ID, PRU ID, and any one of the applicable time window. The WTRU can apply the PRS configuration if (e.g., the current time) is within an applicable time window. The term "ID" can be used interchangeably with "index". The WTRU can receive the beamwidth or line-of-sight direction (AoD) of the PRS from the network. The configuration described herein is not limited to PRS. The configuration parameters described herein can be applied to any (e.g., type) DLRS.

[0121] SRS configuration for positioning In one example, the information indicating the configuration of the SRS (e.g., SRSp) may include (e.g., indicating) any of the following: (1) resource ID, (2) comb offset value, (3) cyclic shift value, (4) starting location in the frequency domain, (5) number of SRSp symbols, (6) shift of the SRSp in the frequency domain, (7) frequency hopping mode, (8) SRSp type (e.g., any of aperiodic, semi-persistent, or periodic), (9) sequence ID used to generate the SRSp (or any other ID used to generate the SRSp sequence), and (10) spatial relationship information indicating which reference signal (e.g., any of DL RS, UL RS, CSI-RS, SRS, or DM-RS) or SSB (e.g., any of SSB ID or SSB cell ID) the SRSp can be spatially associated with, where the SRSp and DL... RS can be spatially aligned, (11) QCL information (e.g., QCL relationship between SRSp and other reference signals or SSBs), (12) QCL type (e.g., QCL type A, QCL type B, QCL type C, QCL type D), (13) resource set ID, (14) list of SRSp resources in the resource set, (15) transmission power related information, (16) path loss reference information, which may include an index of any of the SSB, CSI-RS and PRS, (17) period of SRSp transmission, (18) and spatial information, such as spatial direction information of SRSp transmission (e.g., beam information, transmission angle) and spatial direction information of DL RS reception (e.g., beam ID for receiving DL RS, angle of arrival). The term “ID” can be used interchangeably with “index”.

[0122] Measurement In one example, RSTD can refer to the time difference of arrival between a PRS transmitted from a reference (e.g., a first) TRP and a target (e.g., a second) TRP. A WTRU can be configured with a reference (e.g., a first) TRP index and a target (e.g., a second) TRP index. A WTRU can be configured with an index of the PRS resource to which the measurement is to be performed. A WTRU can determine the time of arrival from a TRP based on one or more PRS resources associated with the TRP. In another example, RSTD can refer to the time difference of arrival between a reference (e.g., a first) PRS transmitted from a reference (e.g., a first) TRP and a target (e.g., a second) PRS transmitted from a target (e.g., a second) TRP. In one example, the reference PRS and the target PRS can be transmitted from the same TRP.

[0123] In one example, the "WTRU Rx-Tx time difference" can refer to the difference between the arrival time of a reference signal transmitted by the TRP and the transmission time of a reference signal transmitted from the WTRU. The WTRU Rx-Tx time difference can be associated with the PRS resource ID and / or the SRSp resource ID.

[0124] WTRU can send one or more measurements in a report (e.g., information indicating the one or more measurements) to the network (e.g., LMF, gNB) via either semi-static (e.g., any of LPP, RRC) or dynamic messages (e.g., any of UCI, ULMAC-CE).

[0125] Messages for environmental IoT devices Messages (including any of configuration messages, control messages, and data messages) can be transmitted to IoT devices (e.g., from either a gNB or a WTRU). Messages can be transmitted by modulating coded bits using modulation schemes such as on / off keying, amplitude shift keying (ASK), frequency shift keying (FSK), etc. A carrier can be used to carry modulation symbols; for example, one or more characteristics of the carrier (e.g., amplitude, frequency, phase, etc.) can be altered to convey modulation symbols. The carrier can be either a single-frequency signal or a signal containing multiple frequencies (e.g., a signal generated using an OFDM modulator).

[0126] Backscattering In one example, a backscattering device can reflect an incident RF signal without generating its own RF signal. In another example, a backscattering device can modulate the incident RF signal Sin(t) to transmit its own data on the reflected signal. This can be achieved using the concept of impedance mismatch. The antenna impedance (which can be referred to as ZA) can be connected to the load impedance at the device (which can be referred to as ZL). The reflection coefficient can be referred to as... The reflected signal can be called... By changing the reflection coefficient over time (e.g., by adjusting the load impedance), any one of the parameters of the reflected signal, such as amplitude or frequency, can be changed (e.g., adjusted). For example, amplitude shift keying (ASK) modulation can be achieved by using... (Non-reflective state / off signal) or (Reflection state / on signal) is used to execute, as described, for example, by C. Xu et al. in “Practical Backscatter Communication Systems for Battery-Free Internet of Things: A Tutorial and Survey of Recent Research,” published in IEEE Signal Processing Magazine, vol. 35, no. 5, pp. 16-27, Sept. 2018. RFID standards are based on backscatter communication, where RFID tags switch reflection coefficients between two states based on the data being transmitted. ASK and PSK can be supported via RFID tags.

[0127] Environmental IoT device types Different types of environmental IoT devices can exist. 3GPP describes three types (device A, device B, and device C) of environmental IoT devices.

[0128] Type A IoT devices may not have energy storage and may not generate RF signals. Type A IoT devices may backscatter incident signals. Type A IoT devices may have capacitors to supply a small amount of power to operate their circuitry. The received RF power can be used to fill the capacitors.

[0129] Environmental IoT devices of device type B can be similar to device types with energy storage. Using the stored energy can include amplifying reflected signals.

[0130] Environmental IoT devices of device type C may include energy storage and independent signal generation circuitry (e.g., active RF components for transmission). This type of device can have lower complexity and power consumption than existing IoT devices (e.g., narrowband (NB) IoT devices).

[0131] IoT devices of types A, B, and C can be demodulated from any of the control and data received from the RAN, depending on the connection topology.

[0132] The embodiments described herein can allow a WTRU to locate with improved accuracy based on its transmission of received PRS with reduced interference from other WTRUs.

[0133] Multiplexing backscatter This article describes multiplexed backscattering.

[0134] In one example, the WTRU can be configured to transmit (e.g., backscatter) the received DL RS at a (e.g., configured) timing offset since the reception of a reference DL RS. The WTRU can determine the reception timing of the reference DL RS and can increment a counter after the WTRU can receive a DL RS that can be transmitted from the network. When the counter reaches (e.g., configured) the timing offset, the WTRU can (e.g., determine) perform a backscatter, for example, the WTRU can transmit the received DL-RS.

[0135] PRS Transmission Timeline Figure 2 This is a diagram illustrating an example of PRS transmission. WTRUs 21 and 22 can receive PRS 23 or DL-RS (e.g., any of CSI-RS, SSB, demodulated reference signal (DMRS), or phase tracking reference signal (PTRS)) from the network. This document uses PRS as an example of a reference signal to describe the embodiment. The embodiments described herein can be applied to any other type of reference signal.

[0136] Figure 3 This is a diagram illustrating an example transmission timeline for TRP. Figure 3 The image shows an example of message and PRS transmission. In this example, the content of the signals and / or reference signals transmitted from the network (e.g., any of the LMF, gNB) is shown in... Figure 3 As shown in the example, message 30 (e.g., first information) can be sent from the network to the WTRU. Message 30 may be followed by the transmission of reference PRS 31. For example, the WTRU may receive an indication from the network (such as configuration information) that the reference PRS 31 following the message (which may be referred to as the first PRS) can be received at least at a second time offset 32 ​​(e.g., T2), where the unit of the second time offset 32 ​​(e.g., T2) can be any of symbols, time slots, frames, and seconds. After the transmission of reference PRS 31, the same or different PRS 33 may be transmitted from the network in any of the following modes: periodic, semi-persistent, and aperiodic.

[0137] In the example of periodically transmitted PRS, the WTRU can receive information from the network indicating one or more configurations (such as, for example, periodicity) regarding the PRS transmission. The WTRU can determine that the periodic transmission can be terminated after the WTRU may have received an indication from the network that the periodic transmission can be terminated.

[0138] In an example of a semi-persistent PRS transmission, the WTRU can receive configuration information, such as indicating the start and end times of the semi-persistent PRS transmission (e.g., the time period for performing reference signal transmission). The start or end time can be indicated in terms of any of the symbols, time slots, frame numbers, system frame numbers (SFNs), and absolute time. In another example, the WTRU can receive configuration information indicating the start time and duration of the semi-persistent transmission (e.g., the time period for performing reference signal transmission). In yet another example, the WTRU can receive an activation message from the network (e.g., via MAC-CE) indicating that the semi-persistent transmission may begin after N units (e.g., any of time slots, frames, or symbols). The WTRU can receive a deactivation message from the network indicating that the semi-persistent transmission may terminate after N units (e.g., any of time slots, frames, or symbols).

[0139] In an example of aperiodic PRS transmission, the WTRU can receive a trigger message from the network (e.g., via downlink control information (DCI)) indicating that the NW can transmit the PRS after N units (e.g., any one of a slot, frame, or symbol).

[0140] Figure 4 This is a diagram illustrating an example timeline for transmitting reference PRS and measured PRS (mPRS) from a network. Figure 4 The reference PRS and mPRS are illustrated as two types of PRS. Messages from the network can indicate one or more configurations of any type of PRS. In one example, the reference PRS and mPRS can be messages of the same type. In this example, the reference PRS and mPRS can be transmitted in the first configuration period 41 (which can be referred to as P1).

[0141] In one example, a reference PRS can be transmitted from the network in a second configuration period 42 (which may be referred to as P2 and may be different from P1). The period of a PRS or mPRS can be expressed (e.g., indicated) in terms of any of time slots, symbols, frames, and absolute time (e.g., seconds). In one example, an mPRS can be transmitted between transmissions of a reference PRS at (e.g., the configured, indicated) number of repetitions (e.g., at the configured number of times). For example, in Figure 4 In the example illustrated, the network can use two timings 43, 44 to transmit two mPRSs between the first reference PRS and the second (e.g., subsequent) reference PRS.

[0142] Figure 5This is a diagram illustrating another example timeline for transmitting the reference PRS and mPRS. In this example, the first timing of mPRS 51 can be transmitted after a configured time offset 52 T1 from the end of the reference PRS 53. The time offset 52 T1 can be expressed (e.g., indicated) in terms of any of the symbols, slots, frames, and absolute time (e.g., seconds). The measured PRS can be transmitted in (e.g., configured) periods 54.

[0143] In one example, the WTRU can be instructed to begin backscattering at a specific time, e.g., a backscatter PRS. In another example, the WTRU can receive messages such as configuration messages and / or control messages. These messages can include information indicating the timing of the backscattering. For example, the timing information can be either a value (e.g., T seconds, N time slots, M frames, K symbols) or a pointer to that value. The WTRU can determine when to begin backscattering based on this value. In one example, the WTRU can (e.g., anticipate) begin backscattering T seconds after the end of the message.

[0144] In one example, the value may be implicitly determined by the WTRU. In another example, the value may be pre-configured. For example, a (e.g., specific) type of message may be used to indicate the transmission of PRS, and the WTRU may determine that it can begin backscattering T seconds after receiving a message of that type. In another example, the message may contain a field indicating the start of PRS transmission.

[0145] In one example, the network element transmitting the PRS can begin transmitting the PRS before the end of T seconds after the message transmission may have ended.

[0146] Figure 6This is a timeline diagram illustrating an example. In this example, the gNB may begin transmitting PRS 61 (T + Td) seconds after the transmission (e.g., configuration, control) message 62 may have ended. The WTRU may begin backscattering (T + D) seconds after the transmission of message 62, where the duration D may include propagation delay, reception processing (such as demodulation), etc. By the time the gNB can begin transmitting PRS, the WTRU may (e.g., has) begun backscattering. For example, the duration D may be any of those configured and indicated by the network (e.g., either the gNB or the LMF). In one example, the duration may be indicated in the WTRU capability. In one example, the WTRU may be configured by the network with a window, where the parameters of the window may include any of the window's start time (e.g., expressed in terms of absolute time, SFN, slot or symbol number, PRS transmission timing, or ID), end time, and duration (e.g., expressed in terms of the number of symbols, slots, or frames). The start and / or stop times and / or duration may be defined (e.g., indicated) with respect to the expected arrival time of the DL reference signal. For example, the start time of the window can be defined (e.g., indicated) as X1 seconds before the expected arrival time of the DL PRS. For example, the end time of the window can be defined (e.g., indicated) as X2 seconds after the expected arrival time of the DL PRS. In one example, the WTRU can determine whether to backscatter (e.g., transmit received signals from the network) during or within one or more configured windows. The WTRU can determine whether to stop backscattering outside one or more configured windows and / or not to backscatter. In one example, if the WTRU receives a DL RS near the end of the window, the WTRU can determine to backscatter the received signal until the end of the window (e.g., the first N symbols of the PRS). In one example, if the WTRU is not configured with a window size that allows the WTRU to backscatter (e.g., all) of the received DL-RS, the WTRU can determine to backscatter a portion of the DL RS (e.g., a subset of the received DL PRS). The WTRU can be configured with a window period. The window can be non-periodic; for example, the WTRU may have received an indication from the network that the window can be activated at a specific timing. In another example, the window can be activated or deactivated by the network, for example, via MAC-CE. In yet another example, the WTRU can determine whether to initiate backscattering during the window period (e.g., based on the window). The window can be used by the WTRU to determine when to perform backscattering. The WTRU can stop backscattering when it receives an instruction from the network to stop backscattering (e.g., afterward).

[0147] Content of messages from the internet Figure 7This is a diagram illustrating example signaling from a network (e.g., any of a gNB or LMF). In this example, the first WTRU 71 (which may be referred to as WTRU_A) and the second WTRU 72 (which may be referred to as WTRU_C) can each be configured with timing offsets of three timings 73 and one timing 74. The configured timing offsets can be used by the WTRUs to determine transmission timing. This configuration can be included in messages received from the network (e.g., in any of the Physical Downlink Control Channel (PDCCH), Physical Downlink Shared Channel (PDSCH), or dedicated signaling). The messages can be included in any of the DCI, MAC-CE, RRC, and LPP messages. The timing offsets can be indicated in terms of symbols, timeslots, frames, SFNs, absolute time (e.g., seconds, minutes, hours), and timings.

[0148] The message may be a query that includes a bit field containing one or more bits.

[0149] The message may include information related to the PRS configuration, indicating any one of the following: (1) sequence ID, (2) one or more repetition factors, (3) information related to the PRS sequence, (4) duration of the PRS transmission, (5) time offset of the PRS transmission with respect to the end of the message, (6) center frequency, and (7) one or more comb patterns.

[0150] A PRS can include a number of N complex values ​​(e.g., associated with it), where N can be an integer. These complex values ​​can correspond to values ​​from any distribution of N resource elements across the frequency domain and N samples in the time domain. Information associated with the reference PRS can include the complex value of the reference PRS or information related to generating the N complex values ​​(such as, for example, indicating the initial seed for the pseudo-random number generator).

[0151] In one example, the WTRU can determine the reference PRS based on its position in the time and / or frequency domains. For instance, the WTRU can receive information associated with (e.g., indication) indices (e.g., frame, time slot, symbol, BWP, component carrier, carrier, start or center frequency of the reference PRS) before receiving the reference PRS. Based on the indicated indices, the WTRU can determine the sequence of the reference PRS.

[0152] Figure 8This is a diagram illustrating an example timeline of PRS transmissions from the network. The WTRU can receive information associated with (e.g., an indication of) index 80, which can be associated with either reference PRS 81 or mPRS 82. The WTRU can determine the sequence of either reference PRS 81 or mPRS 82 based on any of the index 80 information (e.g., slot index, frame index, symbol index, counter) that the WTRU may have received, as well as the seed of the pseudo-random number generator.

[0153] In one example, the WTRU can determine indexing information based on received independent messages. The WTRU can determine indexing information from downlink channels (e.g., PDCCH, PDSCH) in the form of DCI, MAC-CE, RRC messages, and LPP messages.

[0154] Message Structure In one example, a WTRU may receive more than one message from the network, and these messages may include information related to configuration. The WTRU can determine one or more configurations by decoding more than one message. The WTRU may receive different subsets of the configuration in different messages. For example, the WTRU may receive information in a first message indicating an identifier (e.g., WTRU ID) for the WTRU, suggesting that subsequent messages (e.g., second, third messages) may be intended for a WTRU with the identifier indicated in the first message. In another example, the first message may include common configuration information (e.g., the center frequency for transmitting signals, any of the reference PRS sequence), and the second message may include information indicating a timing offset. In one example, the WTRU may determine the configuration obtained in the second message based on the content of the first message. In another example, all the information indicating the configuration may be included in a single message.

[0155] Examples of WTRU identifiers can be any of numbers, digits, etc. Identifiers can include either a seed or a complex number (e.g., including real and imaginary parts), based on which the WTRU can generate WTRU-specific signals or sequences for performing backscattering or transmission operations. WTRU identifiers can include an ID or a portion of an ID stored at the WTRU (e.g., in device memory). WTRU IDs can include an ID assigned to the WTRU by the gNB and / or an ID (e.g., randomly selected by the WTRU during a random access procedure) (e.g., a Radio Network Identifier (RNTI)).

[0156] In one example, the WTRU can receive messages (e.g., any one of the first, second, and third messages) at a single timing (e.g., the same downlink channel may include all messages). The messages can be time-division multiplexed (TDMed), frequency-division multiplexed (FDMed), or encoded in the same message.

[0157] Figure 9 This is a diagram illustrating an example of more than one message arranged in a time-division multiplexing (TDM) configuration. The WTRU can receive the first message 91 in symbols #2 to #M and the second message 92 in symbols #K to #N.

[0158] Figure 10 This diagram illustrates an example of more than one message arranged in a frequency division multiplexing (FDM) configuration. The WTRU can receive the first message 1010 in RE #M+1 to RE #N in the same or different symbols, and the second message 1020 in RE #T to RE #K. In another example, the WTRU can receive sub-messages spread by spreading codes across time and / or frequency.

[0159] Source of the message In one example, the WTRU can receive messages containing details of one or more configurations from a network (e.g., any of an LMF or gNB). In another example, the WTRU can receive messages from a network element that manages configurations or resources (such as a WTRU with server and / or LMF capabilities).

[0160] Relationship between message reception timing and reception reference PRS WTRU can be configured to anticipate the reception or transmission of a reference PRS after a configured time (e.g., N time slots) following the reception or transmission of a message. Figure 3 The diagram illustrates an example where a WTRU can be configured to receive a reference PRS 31 after a second time offset 32 ​​(T2), where T2 can be in units of time slots, seconds, frames, symbols, etc. The WTRU can be configured or pre-configured with a second time offset 32. The WTRU can determine the second time offset 32 ​​based on messages 30 that it can receive from the network. The WTRU can receive messages 30 via broadcast, multicast, and unicast.

[0161] Message format In one example, any message that the WTRU can receive from the network can be received as a standalone message or in a downlink channel (e.g., any of PDCCH and PDSCH). The message can be received in any of DCI, MAC-CE, RRC, and LPP messages. In another example, the message can be appended as header or trailer bits in a downlink channel. The message can be encoded using the downlink channel via any of Code Division Based Duplex (CDM), Time Domain Multiplexing (TDM), and Frequency Domain Multiplexing (FDM). The message can be carried in PDCCH and / or PDSCH.

[0162] WTRU behavior used to monitor messages In one example, a WTRU can be configured to monitor messages. The WTRU can determine the presence of messages on configured (e.g., pre-configured) time and / or frequency resources. The WTRU can receive messages indicating time and / or frequency resources to monitor (e.g., via any of broadcast, multicast, and unicast).

[0163] During random access, the WTRU may select transmission resources (e.g., time and / or frequency resources) to transmit initial signals and / or messages to the gNB. The signals may include a preamble. The message may include a temporary WTRU ID, which may be generated by the WTRU (e.g., randomly generated and / or generated from IDs stored in device memory). In one example, the gNB may assign a WTRU ID to the WTRU. For example, the gNB may acknowledge the ID sent by the WTRU in a message. In another example, the gNB may send an ID to the WTRU. The WTRU ID agreed upon by the gNB and the WTRU can be used for subsequent communication (e.g., transmissions) between the gNB and the WTRU.

[0164] WTRU response to a backscatter request from the network. In one example, the WTRU may receive a request from a network (e.g., via RRC, LPP, MAC-CE, DCI) to perform a backscatter or transmission procedure. In the embodiments described herein, backscattering and transmission can be used interchangeably. The request may be included (e.g., included, indicated) in the message described herein. The request may be expressed in bits or sequences of bits. For example, a bit set to "1" may indicate the start of backscattering, or a bit set to "0" may indicate the transmission of a pre-configured signal at the indicated timing. In the embodiments described herein, when described as an alternative to backscatter transmission, transmitting the pre-configured signal refers to a non-backscatter transmission of the pre-configured signal.

[0165] In one example, the WTRU can receive a DL RS that may indicate the request. In this case, the WTRU can be pre-configured with an RS indicating a request for backscatter. If the WTRU receives an RS from the network, it can determine to perform a backscatter. The WTRU can be configured to monitor the RS at configured periodic intervals.

[0166] In one example, the WTRU can determine the transmission response to the request. The WTRU can determine to transmit a configured (or pre-configured) sequence (or signal) to the network. The request from the network may include either time offset information or frequency resource (e.g., center frequency) information at which the WTRU can transmit a signal as a response. If the WTRU cannot perform backscattering at the indicated time and / or frequency resource, the WTRU can be configured to transmit (e.g., the pre-configured) sequence. In another example, if the WTRU cannot perform backscattering at the indicated time and / or frequency resource, the WTRU can be configured not to transmit (e.g., the pre-configured) sequence.

[0167] Figure 11 This is a diagram illustrating an example protocol exchange between a WTRU and a network. The WTRU can receive a request 1110 from the network instructing it to perform a backscatter. The WTRU can send a response 1120 to the network indicating whether the WTRU is capable of performing a backscatter (e.g., whether the amount of stored or collected power is sufficient). The WTRU can receive information 1130 from the network indicating one or more configurations of the PRS. The WTRU can receive the PRS 1140. The WTRU can transmit a configured or pre-configured signal 1150 as a backscatter.

[0168] Report from WTRU In one example, the WTRU may transmit a report (e.g., information) including any of the following (e.g., measurements): (i) WTRU location information obtained, for example, from a Global Navigation Satellite System (GNSS) or GPS; (ii) timing advance value; (iii) either the RSRP and Reference Signal Received Path Power (RSRPP) of either the DL RS or the signal; (iv) the RSTD between the two DL RSs; (v) the AoA of the DL RS; (vi) the estimated AoD of the DL RS; (vii) the LOS state between the TRP and the WTRU; and (viii) the LOS state of the DL RS. In one example, the presence of a line-of-sight (LOS) or non-line-of-sight (NLOS) path may be indicated along the AoD of the PRS.

[0169] Any information described above (e.g., measurements) may be associated with a timestamp (such as, for example, any one of absolute time, SFN, slot number, symbol number, or frame number), which indicates the time at which the information (e.g., measurements) may have been acquired or determined. WTRU may send reports (e.g., information) based on requests from the network (e.g., any one of gNB or LMF).

[0170] Backscattering based on timing offset Figure 12 This is a diagram illustrating an example timeline where a first reference signal 1210 (e.g., a reference PRS) can be transmitted at four time intervals, and a second reference signal 1220 (e.g., an mPRS) can be transmitted (e.g., repeatedly) between the two reference PRSs 1210 and 1250. In this example, the first 1210 and the second 1220 reference signals can be the same reference signal and can be transmitted at the same interval. In this example, the WTRU may not be configured with information related to the mPRS sequence. The WTRU may be configured with (e.g., only) information related to the reference PRS sequence.

[0171] What signal changes can a WTRU transmit during backscatter operation? In one example, the WTRU may receive information in a message from the network indicating a timing offset (e.g., the number of repetitions after a reference PRS), and the WTRU may wait for this timing offset before performing a backscatter operation. In one example, the backscatter operation may include transmitting what the WTRU can receive. For example, as... Figure 3 As illustrated in the diagram, the WTRU can transmit the received PRS 34 (e.g., Figure 3 The diagram shows that WTRU can transmit (e.g., a reflected transmission of the second PRS 33 (referred to as PRS#2)).

[0172] In another example, the WTRU can transmit either the processed or modulated received PRS to the network. Examples of processing the received PRS include adding either a phase shift or a phase rotation to the received PRS. For example, the WTRU can modify (e.g., process) the received signal as follows: ,in , and The received signal, the transmitted signal, and the phase shift can be represented as functions of time t, respectively. In another example, the WTRU can modify (e.g., process) the received signal as follows: or In the first equation, phase rotation can be added, and in the second equation, phase rotation can be a function of time. The WTRU can receive configuration information from the network related to (e.g., indicating) the amount of phase shift or rotation.

[0173] In one example, the WTRU can determine to apply a pre-configured code (e.g., any of a spreading code or scrambling code) to the received signal and transmit the encoded signal to the network. For example, the WTRU can determine to apply code division multiplexing (CDM) to the received signal. The WTRU can be configured with this code via a configuration message. The WTRU can be configured or pre-configured with more than one code and can receive messages from the network indicating which of the more than one codes to use.

[0174] In one example, a WTRU can be configured with a signal and / or sequence to be transmitted. The signal can be, for example, a reference signal. WTRUs can be configured with N complex numbers and can be transmitted using either OFDM or DFT-s-OFDM. A WTRU can transmit the signal when it receives a PRS at a (e.g., a configured, indicated) timing offset with respect to a reference timing (e.g., the timing at which the WTRU can receive the reference PRS). The sequence can include a complex sequence, which can be generated by a pseudo-number generator with a configured (e.g., random) number seed. In another example, a WTRU can be pre-configured and hard-coded with (e.g., specific) sequences or signals such that (e.g., each) WTRU can be associated with (e.g., unique) a sequence or signal to assist the network in distinguishing WTRUs based on the received sequence or signal. Different WTRUs can be associated with different sequences or signals to be distinguished by the network based on receiving different sequences or signals.

[0175] In one example, the WTRU can be configured with a bit sequence (e.g., 1, -1), and the WTRU can use either amplitude shift keying (ASK) or phase shift keying (PSK) to transmit the configured sequence.

[0176] In one example, based on indications received from the network, the WTRU can determine whether to backscatter or transmit a pre-configured signal. For example, if the WTRU receives a Line-of-Sight (LOS) indicator (e.g., a hard indicator indicating 1 for LOS and 0 for Non-LOS (NLOS), and a soft indicator with a (e.g., real) value between 0 and 1 indicating a likelihood of LOS), the WTRU can determine whether to backscatter or transmit a pre-configured signal if the LOS indicator meets a condition (e.g., greater than a configured threshold, e.g., LOS indicator greater than 0.5, LOS indicator is 1)). The LOS indicator can be associated with a PRS transmitted from the network, indicating the LOS state along the PRS transmission direction. In one example, the LOS indicator can be associated with a TRP from which the PRS can be transmitted, indicating the LOS state between the WTRU and the TRP.

[0177] In one example, the PRS configuration can implicitly identify the device. For example, a WTRU can be (pre-)configured with a (e.g., specific) PRS sequence that can (e.g., uniquely) identify the device (e.g., the WTRU). The (e.g., specific) PRS sequence can be associated with the WTRU. For example, the PRS sequence can include a set of time / frequency resources that follow (e.g., common) signals transmitted (such as, for example, backscattered signals and, for example, common) command signals. If the WTRU receives a PRS associated with it, the WTRU can transmit the received (e.g., modulated) PRS signal to the network. For example, the WTRU can identify its PRS signal (e.g., associated with the WTRU). The WTRU can initiate backscattering of any additional PRS (or other signals) to the network, for example, by adding information according to the embodiments described herein to the backscattered signal.

[0178] In one example, the WTRU can receive broadcast signals from the network. The WTRU can determine the timing offset corresponding to the WTRU.

[0179] In one example, a broadcast message can be decoded as described herein. The message may include a "message type" field (e.g., indication). If the message is a broadcast message, this field (e.g., indication) can be set to one of the broadcast messages. If the message type indicates unicast or multicast, the WTRU can determine a field in the decoded message (e.g., information), which may include the WTRU's ID or the ID of a group to which the WTRU may be associated.

[0180] WTRU behavior in the presence of multipath measurement In one example, the WTRU can perform one or more measurements on the PRS and can determine the presence of multipath in said measurements. For example, the WTRU can detect the PRS and any of its copies and phase-rotated versions after a duration (e.g., N microseconds) following the PRS. The impulse response of the multipath channel can be referred to as... N, and These can be referred to as the number of multipaths, the time-varying channel coefficient at the k-th path, and the time delay at the k-th path, respectively. The WTRU can perform one or more measurements on the first path and the delay paths relative to the first path. (For example, each) path can be associated with a relative delay relative to the first path. The received power of each path can be determined, and the power difference between the first path and the k-th path can be determined.

[0181] In one example, if the WTRU determines the presence of multipath in the channel, the WTRU may determine to transmit a pre-configured signal to the network at a configured timing offset (e.g., at a configured timing offset relative to the reference PRS reception timing). If the WTRU does not detect the presence of multipath (e.g., single-path measurement), the WTRU may perform backscatter (e.g., the WTRU may transmit the received PRS). The WTRU may receive a request from the network (e.g., information indicating the request) to select between transmitting the pre-configured signal or backscattering based on whether multipath exists in the measurement (e.g., determine).

[0182] In one example, the WTRU can backscatter the received signal, which may include one or more multipath components. The WTRU may receive a request from the network (e.g., information indicating the request) to backscatter the received signal independently of (e.g., regardless of) the presence of multipath measurements in the channel.

[0183] In one example, WTRU can determine to start a timer based on the timing of signal reception in the first path.

[0184] Timing offset, timer and reference timing refer to Figure 12 The first WTRU 1201 (which may be referred to as WTRU_A) and the second WTRU 1202 (which may be referred to as WTRU_C) can each be configured with three timings and a timing offset for one timing. Configuring the WTRUs with different timing offsets for backscattering can allow for a reduction in the likelihood of receiving conflicting backscattered signals.

[0185] In one example, the WTRU can determine the timing offset from a message. In another example, the WTRU may be pre-configured with a timing offset (e.g., the WTRU may be hard-coded with a timing offset). In yet another example, the WTRU may report the timing offset value, for example, via (e.g., through) a WTRU capability report.

[0186] The timing offset can be defined with respect to a reference timing. An example of reference timing could be when the WTRU can receive a reference PRS. For instance, the WTRU can (e.g., also) be configured with a number of PRS repetitions. Figure 12 In the example shown, this could be four repetitions, including a reference PRS. The first WTRU 1201 can receive a first PRS 1210 (referred to as PRS #1), which can be the reference PRS. The first WTRU 1201 can determine, based on the sequence of the PRS, that the received first PRS 1210 can be the reference PRS. According to the message, the first WTRU 1201 can determine to transmit the received signal 1240 (e.g., referred to as PRS #4 in the example) at three points from the reception of the reference PRS 1210. The WTRU can start a timer or counter to count the number of points based on the period of the PRS transmission. For example, if the period between two repetitions is two milliseconds (ms), the WTRU can increment the counter at (e.g., every) 2 ms. When the WTRU's timer reaches the end of the repetition cycle (e.g., four or eight ms in this example), the WTRU can reset the timer. If the WTRU determines that the timing offset can occur at three points from the received reference PRS, for example, if the configured period between two consecutive PRSs is 2ms, then 6ms from the received reference PRS, the first WTRU 1201 can transmit the received PRS 1240. Figure 12 (Referring to PRS#4 in this context). The first WTRU 1201 may transmit the received PRS at an opportune time, occurring after a certain amount of time following the receipt of the reference PRS 1210, the amount of time corresponding to a timing offset (e.g., an opportune number) configured for the first WTRU 1201. In one example, each opportune time in a cycle may be associated with an opportune number in a cycle, and the timing offset may correspond to the opportune number in a cycle. The opportune number may be referred to herein as the reference signal opportune number.

[0187] In one example, the WTRU can reset the timer when it can receive the reference PRS or at the reference timing. The WTRU can also reset and start the timer when it can receive the reference PRS or at the reference timing.

[0188] Figure 13This is a timeline example illustrating another example of a timing offset. In this example, WTRU 1301 can be configured with a 5ms timing offset 1305. When WTRU 1301 can receive a reference PRS 1310, WTRU 1301 can start a timer. When the timer reaches the configured timing offset (e.g., 5ms), WTRU can determine to transmit the configured signal or (e.g., the most) recently received signal 1311. In the illustrated example, WTRU 1310 can determine to transmit the reference PRS for a 5ms timing offset. In another example, WTRU can be configured to transmit the next signal closest to the configured timing offset. For example, if WTRU is in Figure 13 In the example shown, a timing offset of 5ms is configured, so the WTRU can determine to transmit PRS#2 and PRS#6. In another example, the WTRU can determine to transmit the signal that is closest to the configured timing offset (e.g., referring to PRS#1 or PRS#2, based on the signal whose receiving timing is closest to the configured timing of 5ms).

[0189] As described in this article, the WTRU can determine the transmission of a configured sequence or modulated signal to the network at a configured timing offset.

[0190] In another example, the reference timing can be (e.g., a specific) time. The WTRU can be configured with timing information (e.g., SFN, any of absolute time, such as 4 PM EST) where the WTRU can expect to start a timer.

[0191] In the embodiments described herein, timers and counters can be used interchangeably.

[0192] In another example, the WTRU may determine whether to increment the counter based on either the RSRP or RSRPP (RSRP per path) of the received PRS, which may not be the reference PRS. The WTRU may increment the counter if the RSRP of the received signal meets a condition (e.g., is above a pre-configured threshold).

[0193] Examples of WTRU capabilities or auxiliary information for WTRUs The WTRU can send its capabilities or auxiliary information to the network. Examples of capabilities include at least one of the following: (1) a lower (e.g., minimum) or upper (e.g., maximum) timing offset for backscattering, (2) a (e.g., minimum) time (e.g., in seconds, symbols, time slots, or frames) for backscattering, (3) the amount of time that may be spent collecting (e.g., a certain) power level (e.g., N watts) for the WTRU, (4) the number of times the WTRU can backscatter (e.g., a certain) power level (e.g., N watts), (5) the type of DL signal or channel that the WTRU can decode, (6) the WTRU ID, (7) the number of transmit and / or receive panels, panel size, and number of elements in the panel, (8) the number or amount of signals that the WTRU can be pre-configured or configured with, (9) one or more signals or spreading codes that the WTRU can hard-code, and (10) the upper (e.g., maximum) transmit power.

[0194] Transmission power In one example, the WTRU might not have sufficient power to transmit the received signal. In such a case, the WTRU can wait until the next opportune moment of the reference PRS before starting the timer. Figure 12 In the example illustrated, the second WTRU 1202 can be configured with a timing offset value. Figure 12 In the example shown, from the first timing to the third timing, the second WTRU 1202 may not be ready to transmit based on the fact that sufficient power has not yet been received. The second WTRU 1202 may wait until the next reception of the reference PRS before starting a timer. The WTRU may start a timer if at least one or a combination of the following conditions are met: if the power used for transmission is higher than (e.g., a pre)configured threshold and / or if the power used for reception and / or decoding is higher than (e.g., a pre)configured threshold.

[0195] The power mentioned above can be the power stored (e.g., retrieved) from energy harvesting.

[0196] The threshold can be configured by the network (e.g., by transmitting configuration information). The WTRU can be pre-configured or hard-coded with a threshold for transmission power.

[0197] The WTRU can send a capability report to the network, indicating the time that may take to charge its battery, for example, via energy harvesting from a first percentage to a second percentage, where the (first / second) percentage can indicate the WTRU's battery charge level (such as, for example, how much charge the WTRU's battery may have).

[0198] Timer stop condition In one example, the WTRU can receive a PRS, and if either the RSRP or RSRPP of the received PRS is below (e.g., a configured) threshold, the WTRU can determine to stop the timer. The WTRU can also stop the timer if the RSRP of the received reference signal is below (e.g., a configured) threshold for more than (e.g., a configured) number of times (e.g., three times).

[0199] Transmission behavior – periodic / semi-persistent / aperiodic In one example, the WTRU can be configured to transmit in any of the following modes: periodic, semi-persistent, and non-periodic. For example, the WTRU may receive a configuration message from the network indicating any of the following: (i) the period of transmission, (ii) the time window for periodic transmission, (iii) an activation ( / deactivation) indication, and (iv) the number of transmissions.

[0200] In one example, the WTRU can be configured with a transmission period (e.g., a time slot, a timing offset at which (e.g., each) opportunity occurs, or 10ms).

[0201] In one example, the WTRU can be configured with a periodic transmission time window (e.g., starting when the WTRU can receive the first reference PRS after it can receive the configuration message, transmissions are made for two seconds every ten milliseconds; starting when the WTRU can receive the configuration message, transmissions are made for two seconds every ten milliseconds).

[0202] In one example, the WTRU can receive an activation message from the network instructing the start of backscattering operation or signal transmission and / or the start of a timer. The WTRU can also receive a deactivation message from the network instructing the stop of backscattering operation or signal transmission and / or the stop of a timer. Either the activation or deactivation message can take the form of bits (e.g., "1" for starting transmission, "0" for stopping transmission) and / or messages (e.g., a first message for starting transmission, a second message for stopping transmission).

[0203] In one example, the WTRU can be configured with a number of transmissions. For instance, the WTRU can be configured to transmit the received PRS three times. The WTRU can transmit the received PRS three times at a configured time offset. The WTRU can receive configuration messages (e.g., indicating the number of transmissions to be repeated, such as the number of transmissions to be repeated).

[0204] Time limit of backscattering In one example, the WTRU can receive a request (e.g., a message indicating the request) to backscatter within N units (e.g., any one of N seconds, N time slots, or N symbols). For example, the WTRU can receive from the network an indication that it can backscatter the received signal within N time slots from the date of receipt (e.g., the indication). If the WTRU cannot transmit the received signal before the indicated time limit, the WTRU can determine to transmit a pre-configured signal. In another example, the WTRU can determine to transmit a message indicating that it cannot transmit any signal.

[0205] WTRU frame format / slot structure In one example, the WTRU can receive configuration information indicating DL and / or UL timing.

[0206] Figure 14 This is a diagram illustrating an example of the DL and UL formats (e.g., time slot structure) of a WTRU. In this example, the WTRU may receive the PRS during a first DL time interval 1410 (e.g., 14 OFDM symbols in the example). The WTRU may transmit the received signal during a first UL time interval 1420 (e.g., 14 OFDM symbols during the UL interval). The WTRU may use configured frequency resources (e.g., bandwidth portions, frequency bands) to transmit the signal. The duration of the DL and / or UL intervals may be any of those pre-configured, configured, or hard-coded by the network.

[0207] Silence of backscattering In one example, the WTRU can be configured with a silent mode. The WTRU can receive a silent mode (e.g., information) from the network indicating which(s) times the WTRU can skip backscatter and / or the WTRU can receive PRS based on the PRS(s) silenced at the indicated times. The silent mode can be configured by the network to reduce interference at the WTRU and / or gNB.

[0208] In one example, the silent mode can be configured semi-statically (e.g., activated, deactivated, and triggered). For example, the WTRU can receive information indicating the silent mode in either an RRC message or an LPP message. The WTRU can determine that the silent mode is activated after the WTRU may have received the configuration message indicating the silent mode or at the indicated timing (e.g., N time slots after the WTRU may have received the configuration message).

[0209] In one example, the WTRU can receive activation or deactivation messages from the network to activate or deactivate (e.g., a configured) silent mode. The WTRU can receive information from the network indicating more than one silent mode, where (e.g., each) a mode can be associated with an index. The WTRU can receive information in the activation or deactivation message indicating an index corresponding to one of (e.g., a configured) silent modes.

[0210] In one example, the WTRU can receive a trigger message that triggers (e.g., one of the configured silent modes), where the trigger message can indicate (e.g., an index of one of the configured silent modes).

[0211] Figure 15 This is a diagram illustrating an example of a WTRU Tx silent mode. The WTRU 1501 can be configured with a silent mode [1 10 1], where the WTRU can receive silent mode information from the network (e.g., each bit can correspond to an indication of when the WTRU will transmit data). For example, as... Figure 15 As shown, WTRU 1501 can be configured with a timing offset. WTRU 1501 can transmit the received PRS 1502, 1505, and 1511 at a timing following the reception of the reference PRS. Depending on the silent mode, WTRU can anticipate skipping (e.g., each) the third transmission timing 1508 among the four transmission timings 1502, 1505, 1508, and 1511. Therefore, depending on the configured silent mode, WTRU can choose not to transmit the received PRS 1508 (referred to as PRS#8).

[0212] Figure 16 This is a diagram illustrating an example of a WTRU Tx silent mode with repeating granularity. In this example, the WTRU1601 can be configured with a silent mode [1 1 0], where (e.g., each) bit can correspond to a PRS transmission timing. Depending on the configured silent mode, the WTRU 1601 can determine that the TRP may not transmit a third PRS in three PRS transmission timings. Figure 16 As shown, WTRU 1601 may not expect to receive the third PRS 1603, the sixth PRS 1606, the ninth PRS 1609, and the twelfth PRS 1612. The number of bits in silent mode can be determined based on the number of times the PRS is repeated. For example, in Figure 16 In the example shown in the figure, the WTRU 1601 can be configured to repeat three times.

[0213] Figure 17This is a diagram illustrating an example of a WTRU Tx silent mode with repeat group granularity. In this example, the WTRU 1701 can be configured with a silent mode [1 0]. The WTRU 1701 can receive an indication (e.g., each) bit from the network that corresponds to an indication of a repeat group. A repeat group can include (e.g., a configured number of repeats), such as three in the example. In this example, the WTRU 1701 can determine that the second of two repeat groups may not be transmitted by the TRP. Figure 17 As illustrated in the diagram, the WTRU may not expect to receive the fourth PRS 1704, the fifth PRS 1705, the sixth PRS 1706, the tenth PRS 1710, the eleventh PRS 1711, and the twelfth PRS 1712.

[0214] Figure 18 This is a diagram illustrating an example of a WTRU Tx silent mode with repeat group granularity and reference PRS transmission. The WTRU1801 can receive from the network an indication that repeat groups can be silenced and that a reference PRS can be transmitted by the TRP. The WTRU1801 can use the reference PRS to determine the timing for counting the number of times.

[0215] WTRU behavior in the absence of transmission power In one example, a WTRU configured to perform backscatter may not be expected to decode the received signal (e.g., to be backscattered). The WTRU may decode (e.g., only) a reference PRS, which can be used as the starting point for the WTRU to determine the timing at which it can transmit the received signal. Different WTRUs may be configured with different timing offsets so that received signals from different WTRUs at the network do not conflict.

[0216] The WTRU can be configured by the network to perform at least one or a combination of the following transport procedure examples.

[0217] In the first example of the transmission procedure, if the power stored at the WTRU is lower than (e.g., the configured) threshold (e.g., the WTRU may be unable to transmit a signal due to lack of power), the WTRU may wait for the next opportunity to receive the reference PRS for transmission.

[0218] In a second example of the transmission procedure, if the power stored at the WTRU is below a threshold (e.g., a configured threshold) (e.g., the WTRU may be unable to transmit a signal due to insufficient power), the WTRU may wait for the next opportunity to receive a reference PRS for transmission. If the WTRU may not be able to accumulate sufficient transmission power within a pre-configured time limit (e.g., ten seconds from when the WTRU may have already received a message related to the reference and / or measurement PRS), the WTRU may terminate the transmission of the received PRS.

[0219] In a third example of the transmission procedure, if the power stored at the WTRU is below (e.g., a configured) threshold (e.g., the WTRU may be unable to transmit a signal due to lack of power), the WTRU may determine to terminate the transmission of the received PRS.

[0220] Termination process The WTRU can determine to terminate a backscatter or transmission operation based on receiving a termination message from the network, for example, via RRC messages, LPP messages, MAC-CE, and DCI, indicating the cessation of the backscatter or transmission operation. In one example, the WTRU can be configured by the network with a time limit and / or duration for performing the backscatter or transmission. The WTRU can start a timer when it can receive a first reference PRS. When the timer may expire or may reach its time limit, the WTRU can stop (e.g., terminate) the backscatter or transmission operation. The WTRU can stop (e.g., terminate) the backscatter or transmission operation after a certain amount of time (e.g., corresponding to the duration) may have elapsed since receiving the first reference PRS.

[0221] In one example, if the WTRU determines that it may not have sufficient power before the non-periodic PRS reception before the end of the WTRU to the PRS transmission (e.g., the indicated time period for performing the PRS transmission) (e.g., the end of the semi-continuous PRS duration), the WTRU may determine to terminate the backscatter or transmission operation.

[0222] If the WTRU determines that it may not have sufficient power to transmit the signal before the end of the reference signal transmission (e.g., within a pre-configured time period for performing a semi-persistent reference signal transmission), the WTRU may decide to terminate the backscatter or transmission operation. For example, the WTRU may determine that it may not be able to collect enough power to transmit the received PRS within N time slots before the end of the semi-persistent PRS transmission from the network.

[0223] Confirm transmission In one example, the WTRU can transmit the received reference PRS to indicate acknowledgment that the reference PRS has been received. In another example, the WTRU can transmit a configured signal to indicate acknowledgment that the reference PRS has been received.

[0224] Example of signal transmission based on time-domain offset In one example, the WTRU (e.g., environmental IoT) can be configured via the network with any of the following: a reference PRS sequence (e.g., pseudo-noise (PN) sequence identifier (ID)), a PRS period (e.g., 2 milliseconds), and the number of PRS timings per cycle (e.g., four). In one example, the reference PRS can be transmitted (e.g., only) at the reference timing.

[0225] In one example, the WTRU can receive from the network a message (e.g., including information) indicating the time offset (e.g., the number of times T after the reference PRS Rx) regarding the timing of the reference PRS Rx. The message may indicate when the WTRU can expect to receive the first PRS after the message (e.g., expected Tx).

[0226] In one example, the WTRU can receive a signal (e.g., if the RSRP is above a threshold) and determine whether the received signal is a reference PRS (e.g., a sequence). If the received reference signal is not a reference PRS, the WTRU can continue searching (e.g., monitoring for a reference PRS) until the WTRU can find (e.g., receive) a reference PRS (e.g., a sequence).

[0227] In one example, based on the reference PRS satisfying a power condition (e.g., RSRP is above a threshold), the WTRU can transmit (e.g., backscatter) the received PRS (which may differ from the reference PRS) at an indicated timing offset relative to the reference PRS (e.g., an indicated number of T timings after the reference PRS). If the WTRU cannot transmit at the indicated timing offset (e.g., based on a lack of (e.g., based on insufficient) Tx power), the WTRU can (e.g., determine) transmit at the next transmission timing (e.g., an indicated number of T timings after the reference PRS).

[0228] In one example, the WTRU can determine not to transmit after it can receive a termination message from the network (e.g., indicating termination of the positioning method).

[0229] Timing offset and FDM-based backscattering This paper describes backscattering based on FDM.

[0230] Message content In one example, the WTRU may receive configuration information indicating any one of one or more timing and frequency characteristics. Examples of frequency characteristics may include any one of the following: (i) center frequency, (ii) bandwidth (e.g., expressed in terms of any one of MHz, resource block, or resource element number), (iii) comb pattern, and (iv) transmission filter ID when the WTRU is configured or pre-configured with more than one transmission filter. The WTRU may determine the transmitted signal based on the configured (e.g., indicated) one or more frequency characteristics.

[0231] In one example, configuration and / or control messages may indicate which subband to use. In one approach, the WTRU may modulate the backscattered signal onto the indicated subband (e.g., the center frequency of the subband).

[0232] Backscattering with configured frequency characteristics In one example, the WTRU can receive information indicating that the received signal is transmitted at a (e.g., configured) timing offset. Furthermore, the WTRU can (e.g., in either the same or different information) receive an indication that the received signal is transmitted at (e.g., configured) frequency characteristics, such as at a configured center frequency and an indicated transmission filter or bandwidth.

[0233] Figure 19 This is a diagram illustrating an example of a configured transmission filter for a WTRU. (See diagram for example.) Figure 19 As illustrated, the WTRU can be configured, pre-configured, and hard-coded with either of two filters, 1910 and 1920, having the same bandwidth (BW). Filters 1910 and 1920 can have different center frequencies, such as... Figure 19 As shown in the diagram. The WTRU can receive an instruction or configuration from the network indicating which filter to use. When the WTRU is capable of transmitting the received DL reference signal, it can use the indicated filter to transmit a portion of the received DL reference signal.

[0234] In one example, the WTRU can modulate the backscattered signal (e.g., using a corresponding waveform such as a sine wave or a square wave) and can shift the backscattered signal to (e.g., a specific) frequency. For example, the WTRU can modulate the backscattered PRS to shift the signal to a first center frequency 1911 (f1) associated with the first filter 1910 or a second center frequency 1922 (f2) associated with the second filter 1920.

[0235] In one example, a WTRU may be configured with more than one frequency range. The configured frequency ranges may overlap in the frequency domain. (For example, each) range may be expressed in terms of the number of any one of resource elements (REs), resource blocks (RBs), and frequency (Hz). (For example, each) range may be associated with a different center frequency or start and / or end points in the frequency domain (e.g., expressed in terms of any one of RB index, RE index, frequency). (For example, each) range may be associated with an (e.g., unique) index.

[0236] Figure 20 is a diagram illustrating an example of FDM-based backscattering. In this example, a WTRU may be pre-configured with Figure 19 the two filters shown in, where the first frequency may be lower than the second frequency, and the bandwidths of the first and second filters may be the same. As an example, filters with center frequencies f1 and f2 may be referred to as filter index 1 and filter index 2, respectively. In this example, the transmitted PRS may span a bandwidth between a start frequency referred to as fs and an end frequency referred to as fe, where the start frequency may be lower than the end frequency (fs < fe). In this example, the first WTRU 2001, the second WTRU 2002, the third WTRU 2003, and the fourth WTRU 2004 may be configured with timing offsets of three occasions, three occasions, one occasion, and one occasion, respectively. The first WTRU 2001, the second WTRU 2002, the third WTRU 2003, and the fourth WTRU 2004 may be configured with filter indices 1, 2, 1, and 2, respectively.

[0237] As Figure 20As shown, the first WTRU 2001 can transmit the fourth received PRS 2040 (referred to as PRS#4) and the first eighth received PRS 2081 (referred to as PRS#8) using a filter with a first index (referred to as index 1) three times after receiving reference PRS 2010 and 2050. The second WTRU 2002 can transmit the second eighth received PRS 2082 (referred to as PRS#8) using a filter with a second index (referred to as index 2) three times after receiving reference PRS 2050. The third WTRU 2003 can transmit the first sixth received PRS 2061 (referred to as PRS#6) using a filter with a first index one time after receiving reference PRS 2050. The fourth WTRU 2004 can transmit the second received PRS 2020 (referred to as PRS #2) and the second sixth received PRS 2062 (referred to as PRS #6) using a filter with a second index at a certain point after receiving the reference PRS 2010, 2050. As shown in this example, collisions between backscattering WTRUs can be avoided.

[0238] Examples of signal transmission based on time offset and FDM In one example, the WTRU (e.g., environmental IoT) can be configured via the network with any of the following: a reference PRS sequence (e.g., pseudo-noise (PN) sequence identifier (ID)), a PRS period (e.g., 2 milliseconds), and the number of PRS timings per cycle (e.g., four). In one example, the reference PRS can be transmitted (e.g., only) at the reference timing.

[0239] In one example, the WTRU can receive from the network a message (e.g., including information) indicating the time offset (e.g., the number of times T after the reference PRS Rx) regarding the timing of the reference PRS Rx. The message may indicate when the WTRU can expect to receive the first PRS after the message (e.g., expected Tx).

[0240] In one example, the WTRU may receive a second message indicating a frequency hopping mode (such as, for example, a WTRU-specific offset). Examples of frequency hopping modes may include [1 0], where "1" may correspond to the upper subband and "0" may correspond to the lower subband. The index (1 or 0) may be determined based on a reference timing index (e.g., mod(reference frequency hopping index, number of PRS timings per cycle) + WTRU-specific offset).

[0241] In one example, the WTRU can receive a signal (e.g., if the RSRP is above a threshold) and can determine whether the received signal is a reference PRS. If the received signal is not a reference PRS, the WTRU can continue searching (e.g., it can monitor for a reference PRS) until the WTRU can receive a reference PRS. If the WTRU cannot transmit at the indicated timing offset (e.g., based on a lack of Tx power), the WTRU can determine to transmit at the next transmission opportunity (e.g., T opportunities after the reference PRS).

[0242] The WTRU can transmit the indicated subband of the received PRS at an indicated timing offset of the reference PRS (e.g., T times of the reference PRS).

[0243] Other examples of time-shifted and FDM-based signal transmission In one example, the WTRU can receive the first message indicating the timing offset (e.g., T ms).

[0244] In one example, the WTRU may receive a second message indicating a frequency hopping mode (e.g., the starting subband, whether it alternates or repeats, and the number of repetitions if repeating). Examples of frequency hopping modes may include [1 0], where "1" may correspond to the upper subband and "0" may correspond to the lower subband.

[0245] In one example, WTRU can receive a reference PRS (if the method is based on repetition timing).

[0246] In one example, the WTRU can receive the target PRS.

[0247] In one example, the WTRU can be transmitted in the PRS subband indicated in the mode at an indicated timing offset relative to the reference PRS (e.g., T milliseconds after receiving the reference PRS).

[0248] In one example, the WTRU can stop transmitting after the PRS has been transmitted a specified number of times.

[0249] Backscattering with configured frequency hopping Figure 21 This is a diagram illustrating an example configuration of timing offsets and frequency hopping modes. In this example, the WTRU can be configured with one or more timing offsets and one or more frequency hopping modes.

[0250] like Figure 21As shown, the first WTRU 2101, the second WTRU 2102, the third WTRU 2103, and the fourth WTRU 2104 can be configured with timing offsets of three timings 2130, three timings 2130, one timing 2110, and one timing offset, respectively. In one example, the first WTRU 2101 and the second WTRU 2102 can be configured with a first frequency hopping mode 2111. The third WTRU 2103 and the fourth WTRU 2104 can be configured with a second frequency hopping mode 2112.

[0251] The first frequency hopping mode 2111 can be represented by [1 2], and the second frequency hopping mode 2112 can be represented by [2 1]. The elements in the vector [1 2] can indicate, for example, Figure 19 The filter index is illustrated in the figure. Using frequency hopping in the frequency domain (e.g., using different Tx filters at different times) can allow for improved bandwidth coverage and improved quality of timing, power, phase, and / or angle measurements.

[0252] In one example, WTRU can receive information indicating the frequency hopping mode and time offset value in the same message or in different (e.g., separate) configuration messages.

[0253] In one example, the WTRU can determine which filter index to use based on the configured frequency hopping pattern sequence. For instance, the WTRU can determine to use the filter associated with the first index in the pattern during its first transmission or backscatter after receiving a configuration message. After using the filter associated with the first index, the WTRU can determine to use the filter associated with the second index for subsequent transmissions or backscatters.

[0254] Figure 22This is a diagram illustrating an example of backscattering with frequency hopping and time shifting. The first WTRU 2201 can transmit a fourth received PRS 2240 (referred to as PRS#4) and a first eighth received PRS 2281 (referred to as PRS#8) using filters with first index 2211 and second index 2212, respectively, three times after receiving reference PRS 2210 and 2250. The second WTRU 2202 can transmit a second eighth received PRS 2282 (referred to as PRS#8) using a filter with first index 2211, three times after receiving reference PRS 2250. The third WTRU 2203 can transmit a first sixth received PRS 2261 (referred to as PRS#6) using a filter with second index 2212, one time after receiving reference PRS 2250. The fourth WTRU 2204 can transmit the second received PRS 2220 (referred to as PRS #2) and the second sixth received PRS 2262 (referred to as PRS #6) using filters with a second index 2212 and a first index 2211, respectively, after a certain point following the receipt of reference PRS 2210 and 2250. As shown in this example, collisions between backscattering WTRUs can be avoided.

[0255] Figure 23 This is a diagram illustrating an example method 2300 for multiplexing backscattering. Method 2300 can be implemented in a WTRU. As shown at 2310, the WTRU can receive first information indicating a first time offset with respect to a first reference signal transmission. As shown at 2320, the WTRU can receive the first reference signal transmission. As shown at 2330, the WTRU can determine whether the received first reference signal transmission satisfies a power condition. As shown at 2340, the WTRU can receive a second reference signal transmission. As shown at 2350, the WTRU can transmit a third reference signal transmission based on (1) the received second reference signal transmission, (2) the indicated first time offset, and (3) whether the received first reference signal transmission satisfies a power condition. For example, the third reference signal transmission can be transmitted based on the received second reference signal transmission at the indicated time offset with respect to the first reference signal transmission and in response to the power condition being satisfied (e.g., for either the received first reference signal transmission or the received second reference signal transmission).

[0256] In various embodiments, the third reference signal transmission can be performed by backscattering the second reference signal transmission.

[0257] In various embodiments, the third reference signal transmission can be transmitted by reflecting the energy received from the second reference signal transmission.

[0258] In various embodiments, the WTRU may receive (e.g., first) configuration information indicating any one of a reference signal sequence, a reference signal period, and the number of reference signal cycles per cycle.

[0259] In various embodiments, the first information may indicate a second time offset between the first information transmission and the first reference signal transmission.

[0260] In various embodiments, when the power of the received reference signal is higher than a threshold (e.g., a first), the received first reference signal transmission can satisfy a power condition (e.g., the power condition can be satisfied for the received first reference signal transmission).

[0261] In various embodiments, the WTRU may transmit a third reference signal transmission if the received first reference signal transmission satisfies the power condition.

[0262] In various embodiments, the WTRU can determine that the received first reference signal transmission satisfies the power condition, and the WTRU can transmit the third reference signal transmission at an indicated first time offset with respect to the first reference signal transmission.

[0263] In various embodiments, if the received first reference signal transmission does not meet the power condition, the WTRU can (e.g., operably) monitor subsequent first reference signal transmissions.

[0264] In various embodiments, the WTRU may transmit a third reference signal transmission if (e.g., in response to) the received second reference signal transmission satisfying a power condition (e.g., if (e.g., if the power of the (second) reference signal received is higher than (e.g., a second) threshold).

[0265] In various embodiments, if the received second reference signal transmission does not meet the power condition, the WTRU may receive a fourth reference signal transmission and may transmit a third reference signal transmission based on the received fourth reference signal transmission at a third time offset with respect to the first reference signal transmission, wherein the third time offset may be an integer multiple of the first time offset.

[0266] In various embodiments, the first information may indicate a frequency hopping mode.

[0267] In various embodiments, the frequency hopping mode may include a pattern of multiple subband indices. In various embodiments, a first time offset may be associated with an index, and the WTRU may determine a subband index from the multiple subband indices based on the index of the first time offset.

[0268] In various embodiments, the WTRU can transmit a third reference signal transmission in a subband associated with a subband index.

[0269] Figure 24 This is a diagram illustrating another example method 2400 for multiplexing backscatter. Method 2400 can be implemented in a WTRU. As shown at 2410, the WTRU can (e.g., from the network) receive first information indicating a first time offset regarding a first reference signal transmission. As shown at 2420, the WTRU can (e.g., from the network) receive the first reference signal transmission. As shown at 2440, the WTRU can receive a second reference signal transmission. As shown at 2450, the WTRU can transmit a third reference signal transmission at the indicated first time offset (e.g., to the network) based on the received second reference signal transmission. In various embodiments, the third reference signal transmission can be transmitted in response to a power condition being met.

[0270] In various embodiments, the transmission of the third reference signal may include the transmission of the backscattered second reference signal.

[0271] In various embodiments, transmitting a third reference signal may include reflecting energy received from a second reference signal transmission.

[0272] In various embodiments, the WTRU may receive first configuration information indicating any one of the reference signal sequence, reference signal period, and number of reference signal cycles per cycle.

[0273] In various embodiments, the first time offset may correspond to the number of times the reference signal is cyclically received.

[0274] In various embodiments, the first information may indicate a second time offset between the first information transmission and the first reference signal transmission.

[0275] In various embodiments, a third reference signal transmission may be transmitted in response to the power condition for the transmission of the received first reference signal being met.

[0276] In various embodiments, a power condition can be satisfied for the received first reference signal if the power of the first reference signal is higher than a first threshold.

[0277] In various embodiments, a third reference signal transmission may be transmitted in response to the power condition for the received second reference signal transmission being met.

[0278] In various embodiments, a power condition can be satisfied for the transmission of the received second reference signal if the power of the received second reference signal is higher than a second threshold.

[0279] In various embodiments, the first information may indicate a frequency hopping mode.

[0280] In various embodiments, the frequency hopping mode may include a pattern of multiple subband indices. In various embodiments, a first time offset may be associated with an index, and the WTRU may determine a subband index from the multiple subband indices based on the index of the first time offset.

[0281] In various embodiments, transmitting the third reference signal may include transmitting the third reference signal in a subband associated with a subband index.

[0282] In various embodiments, the WTRU may receive second configuration information indicating the time period for performing reference signal transmission.

[0283] In various embodiments, the WTRU can determine that it may not have enough power to perform reference signal transmission before the end of the time period.

[0284] In various embodiments, the WTRU may terminate the reference signal transmission based on the fact that the WTRU does not have sufficient power to perform the reference signal transmission before the end of the time period.

[0285] In various embodiments, the WTRU may determine that it may not have sufficient power to perform reference signal transmission within the time limit before the end of the time period.

[0286] In various embodiments, the WTRU may terminate the reference signal transmission based on the fact that the WTRU does not have sufficient power to perform the reference signal transmission within a time limit before the end of the time period.

[0287] Figure 25 This is a diagram illustrating an example method 2500 for multiplexing backscattering. Method 2500 can be implemented in a network element. As shown at 2510, the network element can transmit first information to a first WTRU. In various embodiments, the first information can indicate a first time offset of a first reference signal transmission among a plurality of reference signal transmissions. As shown at 2520, the network element can transmit second information to a second WTRU. In various embodiments, the second information can indicate a second time offset of the first reference signal transmission. In various embodiments, the first time offset can be different from the second time offset. As shown at 2530, the network element can transmit a plurality of reference signal transmissions. As shown at 2540, the network element can receive from the first WTRU a second reference signal transmission at a first time offset of the first reference signal transmission. As shown at 2550, the network element can receive from the second WTRU a third reference signal transmission at a first time offset of the first reference signal transmission.

[0288] Figure 26 This is a diagram illustrating an example method 2600 for backscattering in the presence of multipath. Method 2600 can be implemented in a WTRU. As shown at 2610, the WTRU can receive information indicating a time offset regarding a reference signal transmission. As shown at 2620, the WTRU can receive the reference signal transmission. As shown at 2630, the WTRU can perform measurements on the reference signal transmission to detect the presence of multipath. As shown at 2640, the WTRU can transmit a pre-configured signal at the indicated time offset regarding the reference signal transmission. In various embodiments, the pre-configured signal can be transmitted in response to the detection of the presence of multipath.

[0289] Figure 27 This is a diagram illustrating an example method 2700 for backscattering in the presence of multipath. Method 2700 can be implemented in a network element. As shown at 2710, the network element can transmit information indicating a time offset regarding the transmission of a reference signal. As shown at 2720, the network element can transmit the reference signal transmission. As shown at 2730, the network element can receive a pre-configured signal at the indicated time offset regarding the transmission of the reference signal. In various embodiments, the pre-configured signal can indicate the detection of multipath at the WTRU.

[0290] Although not explicitly described, the embodiments described herein can be used in any combination or sub-combination. For example, the principles are not limited to the described variations, and any arrangement of variations and embodiments can be used.

[0291] Furthermore, any features, variations, or embodiments described for the method are compatible with devices including components for processing the disclosed method, devices including circuitry (including any one of a transmitter, receiver, processor, and memory) configured to process the disclosed method, computer program products including program code instructions, and non-transitory computer-readable storage media storing program instructions. Additionally, any features, variations, or embodiments described for the WTRU are compatible with network elements of cellular networks (e.g., infrastructure).

[0292] Although features and elements have been provided above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in combination with other features and elements. This disclosure is not limited to the specific embodiments described herein, which are intended to illustrate various aspects. Many modifications and variations can be made without departing from the spirit and scope of the invention, as will be apparent to those skilled in the art. No element, action, or instruction used in the description of this application should be construed as critical or essential to the invention unless expressly provided so. Based on the foregoing description, functionally equivalent methods and apparatuses within the scope of this disclosure will be apparent to those skilled in the art, in addition to those methods and apparatuses listed herein. Such modifications and variations are intended to fall within the scope of the appended claims. This disclosure is limited only by the terms of the appended claims and the full scope of equivalents thereof. It should be understood that this disclosure is not limited to specific methods or systems.

[0293] For simplicity, the foregoing embodiments are discussed in terms of the terminology and structure of devices with infrared capabilities (i.e., infrared transmitters and receivers). However, the embodiments discussed are not limited to these systems, but can be applied to other systems that use other forms of electromagnetic waves or non-electromagnetic waves (such as sound waves).

[0294] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the term "video" or the term "image" can refer to any of a snapshot, a single image, and / or multiple images displayed on a time-based basis. As another example, when referred to herein, the term "user equipment" and its abbreviation "UE," the term "remote," and / or the term "head-mounted display" and its abbreviation "HMD" can mean or include (i) a wireless transmit and / or receive unit (WTRU); (ii) any of several embodiments of a WTRU; (iii) a device particularly configured with some or all of the constructs and functions of a WTRU and having wireless and / or wired capabilities (e.g., tetherable); (iv) a device configured with fewer than all the constructs and functions of a WTRU and having wireless and / or wired capabilities; or (iv) something like that. Figure 1A-1DDetails of an example WTRU, which may represent any WTRU described herein, are provided. As another example, the various embodiments disclosed above and below are described as utilizing a head-mounted display. Those skilled in the art will recognize that devices other than head-mounted displays can be utilized, and some or all of this disclosure and the various disclosed embodiments can be modified accordingly without excessive experimentation. Examples of such other devices may include drones or other devices configured to stream information to provide an adaptive, realistic experience.

[0295] Furthermore, the methods provided herein can be implemented in computer programs, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROMs and digital multifunction discs (DVDs). The processor associated with the software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0296] Variations of the methods, apparatus, and systems provided above are possible without departing from the scope of the invention. Given the wide variety of embodiments that can be applied, it should be understood that the illustrated embodiments are merely examples and should not be construed as limiting the scope of the appended claims. For example, embodiments provided herein include handheld devices that may include or be used with any suitable voltage source (such as a battery, etc.) providing any suitable voltage.

[0297] Furthermore, in the embodiments provided above, a processing platform, computing system, controller, and other devices, including a processor, are mentioned. These devices may include at least one central processing unit (“CPU”) and memory. According to the practice of those skilled in the art of computer programming, references to symbolic representations of actions and operations or instructions can be executed by various CPUs and memories. Such actions and operations or instructions may be referred to as being “executed,” “computer-executed,” or “CPU-executed.”

[0298] Those skilled in the art will understand that the actions and symbols representing operations or instructions include the CPU's manipulation of electrical signals. Electrical systems represent data bits that can cause a final transformation or reduction of electrical signals, and data bits are maintained in memory locations within memory systems, thereby reconfiguring or otherwise altering the CPU's operation and other signal processing. The memory location maintaining the data bits is a physical location having specific electrical, magnetic, optical, or organic properties corresponding to or representing the data bits. It should be understood that the embodiments are not limited to the platforms or CPUs described above, and other platforms and CPUs may support the provided methods.

[0299] Data bits can also be maintained on a computer-readable medium, including disks, optical disks, and any other CPU-readable volatile (e.g., random access memory (RAM)) or non-volatile (e.g., read-only memory (ROM)) mass storage system. The computer-readable medium can include cooperative or interconnected computer-readable media that reside exclusively on the processing system or are distributed across multiple interconnected processing systems, which may be local or remote within the processing system. It should be understood that the embodiments are not limited to the above-described memories, and other platforms and memories may support the provided methods.

[0300] In the illustrative embodiments, any of the operations, processes, etc., described herein can be implemented as computer-readable instructions stored on a computer-readable medium. These computer-readable instructions can be executed by a processor of a mobile unit, network element, and / or any other computing device.

[0301] There is little difference between the hardware and software implementations of the various aspects of the system. The use of hardware or software is often (but not always, as the choice between hardware and software may become important in certain contexts) a design choice representing a cost-efficiency trade-off. Various means can exist to implement the processes and / or systems and / or other technologies described herein (e.g., hardware, software, and / or firmware), and the preferred means can vary depending on the context of the deployment of the processes and / or systems and / or other technologies. For example, if the implementer determines that speed and accuracy are of paramount importance, the implementer may choose a primarily hardware and / or firmware approach. If flexibility is of paramount importance, the implementer may choose a primarily software implementation. Alternatively, the implementer may choose some combination of hardware, software, and / or firmware.

[0302] The foregoing detailed description has illustrated various embodiments of the apparatus and / or processes using block diagrams, flowcharts, and / or examples. Within the scope of such block diagrams, flowcharts, and / or examples encompassing one or more functions and / or operations, those skilled in the art will understand that each function and / or operation in such block diagrams, flowcharts, or examples can be implemented individually and / or collectively by a wide variety of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein can be implemented via application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integration formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein can be implemented, in whole or in part, equivalently in an integrated circuit, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing circuitry and / or writing code for software and / or firmware in accordance with this disclosure will be entirely within the skill of those skilled in the art. Furthermore, those skilled in the art will understand that the mechanisms of the subject matter described herein can be distributed as a program product in various forms, and that the illustrative embodiments of the subject matter described herein apply regardless of the specific type of signal-bearing medium used to actually perform the distribution. Examples of signal-bearing media include, but are not limited to, the following: recordable media, such as floppy disks, hard disk drives, CDs, DVDs, digital magnetic tapes, computer memory, etc.; and transmission media, such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, etc.).

[0303] Those skilled in the art will recognize that it is common practice in the art to describe devices and / or processes in the manner set forth herein, and subsequently integrate such described devices and / or processes into data processing systems using engineering practice. That is, at least a portion of the devices and / or processes described herein can be integrated into a data processing system through a reasonable number of experiments. Those skilled in the art will recognize that a typical data processing system typically includes one or more of the following: a system unit housing, a video display device, a memory such as volatile and non-volatile memory, a processor such as a microprocessor and a digital signal processor, a computing entity such as an operating system, drivers, a graphical user interface and applications, one or more interactive devices such as a touchpad or screen, and / or a control system including feedback loops and control motors (e.g., feedback for sensing position and / or speed, control motors for moving and / or adjusting components and / or quantities). A typical data processing system can be implemented using any suitable commercially available components, such as those commonly found in data computing / communication and / or network computing / communication systems.

[0304] The topics described herein sometimes illustrate different components included within or connected to other components. It should be understood that the architectures depicted are merely examples, and many other architectures can indeed be implemented to achieve the same functionality. Conceptually, any arrangement of components that achieve the same functionality is effectively “associated” to achieve the desired functionality. Therefore, any two components combined in this document to achieve a particular function can be considered “associated” with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components that can be so associated can also be considered “operably coupled” to each other to achieve the desired functionality. Specific examples of operational coupling include, but are not limited to, physically matable and / or physically interactive components and / or wirelessly interactive components and / or logically interactive components.

[0305] Regarding the use of virtually any plural and / or singular terms in this document, those skilled in the art may appropriately translate from plural to singular and / or from singular to plural depending on the context and / or application. For clarity, various singular / plural arrangements may be explicitly described herein.

[0306] Those skilled in the art will understand that, generally, the terminology used herein, and especially in the appended claims (e.g., the body of the appended claims), is generally intended as “open” terms (e.g., the term “comprising” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “at least having,” the term “comprising” should be interpreted as “including but not limited to,” etc.). Those skilled in the art will further understand that if the intent is to specify a particular number of items recounted in the introduced claim, such intent will be explicitly detailed in the claim, and if no such recount is made, such intent does not exist. For example, the term “single” or similar language may be used where the intent is only for one item. To aid understanding, the appended claims and / or the description herein may include the use of introductory phrases “at least one” and “one or more” to introduce the recounting of a claim. However, the use of such phrases should not be construed as implying that a claim recitation introduced by the indefinite article "a" or "an" limits any particular claim to include only one such recitation, even when the same claim includes the introductory phrase "one or more" or "at least one" and indefinite articles such as "an" or "one" (e.g., "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same applies to the use of definite articles used to introduce a claim recitation. Furthermore, even if the specific number of recitations in the introduced claim is explicitly stated, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the number of recitations (e.g., the simple statement "two recitations" without other modifiers means at least two recitations, or two or more recitations). Furthermore, in cases where conventions such as "at least one of A, B, and C" are used, generally, such a construction is intended to be based on the meaning of the convention as would be understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In cases where conventions such as "at least one of A, B, or C" are used, generally, such a construction is intended to be based on the meaning of the convention as would be understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Those skilled in the art will further understand that any transition words and / or phrases that actually represent two or more alternative terms, whether in the specification, claims, or drawings, should be understood to imply the possibility of including one, any, or both terms.For example, the phrase “A or B” will be understood to include the possibility of “A” or “B” or “A and B”. Furthermore, as used herein, the term “any one of…” following a list of multiple items and / or multiple item categories is intended to include, alone or in combination with other items and / or other item categories, “any one,” “any combination,” “any multiple,” and / or “any combination of multiples.” Furthermore, as used herein, the term “set” is intended to include any number of items, including zero. Furthermore, as used herein, the term “quantity” is intended to include any number, including zero. And as used herein, the term “multiple” is intended to be synonymous with “multiple.”

[0307] Furthermore, in cases where features or aspects of this disclosure are described in accordance with the Markush Group, those skilled in the art will recognize that this disclosure is therefore also described in accordance with any individual member of the Markush Group or a subgroup of its members.

[0308] As those skilled in the art will understand, for any and all purposes, such as for providing a written description, all scopes disclosed herein also include any and all possible subscopes and combinations thereof. Any listed scope can be readily considered sufficiently descriptive and makes it possible to decompose the same scope into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc. Those skilled in the art will also understand that all language (such as “up to,” “at least,” “greater than,” “less than,” etc.) includes the stated numbers and refers to a scope that can subsequently be decomposed into subscopes as discussed above. Finally, as those skilled in the art will understand, a scope includes each individual member. Thus, for example, a group having 1-3 subscopes refers to a group having 1, 2, or 3 subscopes. Similarly, a group having 1-5 subscopes refers to a group having 1, 2, 3, 4, or 5 subscopes, and so on.

[0309] Furthermore, the claims should not be construed as being limited to the provided order or elements unless expressly stated otherwise. Additionally, the use of the term "means for..." in any claim is intended to refer to... The claim format is either device plus function, and any claim without the term "device for..." is not intended to be so.

Claims

1. A wireless transmit / receive unit (WTRU) comprising circuitry including any one of a transmitter, a receiver, a processor, and a memory, the WTRU being configured to: Receive first information indicating a first time offset regarding the transmission of the first reference signal; Receive the first reference signal transmission; Receive the second reference signal transmission; as well as Based on the received second reference signal transmission, a third reference signal transmission is transmitted at a first time offset from the first reference signal transmission, wherein the third reference signal transmission is transmitted in response to a power condition being satisfied.

2. The WTRU of claim 1, wherein the WTRU is configured to transmit a third reference signal, the transmission of which includes the WTRU being configured to backscatter a second reference signal.

3. The WTRU according to any one of claims 1 to 2, wherein the WTRU is configured to transmit a third reference signal transmission including the WTRU being configured to reflect energy received from the second reference signal transmission.

4. The WTRU according to any one of claims 1 to 3, wherein the WTRU is configured to receive first configuration information indicating any one of the reference signal sequence, the reference signal period, and the number of reference signal times per cycle.

5. The WTRU of claim 4, wherein the first time offset corresponds to the number of times the reference signal occurs in the loop.

6. The WTRU according to any one of claims 1 to 5, wherein the first information indicates a second time offset between the first information transmission and the first reference signal transmission.

7. The WTRU according to any one of claims 1 to 6, wherein a third reference signal transmission is transmitted in response to the power condition for the received first reference signal transmission being satisfied.

8. The WTRU according to any one of claims 1 to 7, wherein, If the power of the first reference signal received in the transmission of the first reference signal is higher than the first threshold, the power condition is satisfied for the transmission of the first reference signal.

9. The WTRU according to any one of claims 1 to 8, wherein a third reference signal transmission is transmitted in response to the power condition for the received second reference signal transmission being satisfied.

10. The WTRU according to any one of claims 1 to 9, wherein, If the power of the received second reference signal is higher than the second threshold, the power condition is satisfied for the transmission of the received second reference signal.

11. The WTRU according to any one of claims 1 to 10, wherein the first information indicates a frequency hopping mode.

12. The WTRU of claim 11, wherein the frequency hopping mode includes a pattern of multiple subband indices, wherein a first time offset is associated with an index, and wherein the WTRU is configured to determine a subband index from the multiple subband indices based on an index of the first time offset.

13. The WTRU of claim 12, wherein the WTRU is configured to transmit a third reference signal transmission includes the WTRU being configured to transmit a third reference signal transmission in a subband associated with a subband index.

14. The WTRU according to any one of claims 1 to 13, wherein the WTRU is configured to receive second configuration information indicating a time period for performing reference signal transmission.

15. The WTRU of claim 14, wherein the WTRU is configured to determine that the WTRU does not have sufficient power to perform reference signal transmission before the end of the time period.

16. The WTRU of claim 14, wherein the WTRU is configured to terminate the execution of reference signal transmission based on the fact that the WTRU does not have sufficient power to perform reference signal transmission before the end of the time period.

17. The WTRU of claim 14, wherein the WTRU is configured to determine that the WTRU does not have sufficient power to perform reference signal transmission within a time limit prior to the end of the time period.

18. The WTRU of claim 14, wherein the WTRU is configured to terminate the reference signal transmission based on the fact that the WTRU does not have sufficient power to perform the reference signal transmission within a time limit prior to the end of the time period.

19. A method implemented in a wireless transmit / receive unit (WTRU), the method comprising: Receive first information indicating a first time offset regarding the transmission of the first reference signal; Receive the first reference signal transmission; Receive the second reference signal transmission; as well as Based on the received second reference signal transmission, a third reference signal transmission is transmitted at a first time offset from the first reference signal transmission, wherein the third reference signal transmission is transmitted in response to a power condition being satisfied.

20. A method implemented in a network element, the method comprising: Transmit first information to a first wireless transmit / receive unit (WTRU), wherein the first information indicates a first time offset of a first reference signal transmission among a plurality of reference signal transmissions; Transmit second information to the second WTRU, wherein the second information indicates a second time offset with respect to the transmission of the first reference signal, and wherein the first time offset is different from the second time offset; Transmit the plurality of reference signals; Receive a second reference signal transmission at a first time offset from the first reference signal transmission from the first WTRU; as well as The third reference signal transmission is received from the second WTRU at a second time offset from the first reference signal transmission.

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