Method for supporting positioning with mobile access node

Abstract

A wireless transmit / receive unit (WTRU) can be configured to receive configuration information indicating a plurality of association sets. Each association set can include a plurality of respective time instances and a plurality of respective timing advance (TA) offsets. The WTRU can send an indication of at least one of a mobile network node identification or WTRU location information. The WTRU can receive an indication of a first association set of the plurality of association sets. The WTRU can start transmitting a first sounding reference signal (SRS) (SRSp) transmission for positioning at a first time. The first time can be determined based on at least a first TA offset of the first association set and a respective first instance of time associated with the first TA offset.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 395,904, filed on August 8, 2022, the entire contents of which are incorporated herein by reference. Background Art

[0003] In the downlink positioning method, a positioning reference signal (PRS) may be transmitted to the WTRU from multiple transmit-receive points (TRPs). The WTRU may observe multiple reference signals and may measure the time difference of arrival (TDoA) between a pair of PRSs. The WTRU may then transmit the measured reference signal time difference (RSTD) to the network (e.g., location management function (LMF)). In addition, the WTRU may transmit the measured reference signal received power (RSRP) for each PRS. Based on the returned measurement results, the LMF may perform positioning of the WTRU. Additionally or alternatively, the WTRU may report RSRP for a downlink (DL) angle-based positioning method.

[0004] In the uplink positioning method, the WTRU may transmit a sounding reference signal (SRS) configured by the radio resource control (RRC) for positioning to the TRP. In the timing-based method, the TRP may measure the relative time of arrival (RTOA) for the received SRS and may report the measurement value to the LMF. The WTRU may report the RSRP of the SRS. In the angle-based uplink positioning method, the TRP may measure the angle of arrival and may report the angle of arrival to the LMF.

[0005] In the uplink and downlink positioning methods, the WTRU may measure the Rx-Tx time difference between the received PRS and the transmitted SRS. The WTRU may report the measured Rx-Tx time difference to the LMF. The WTRU may report the measured RSRP of the PRS. Similarly, at the TRP, the Rx-Tx difference between the received SRS and the transmitted PRS may be calculated.

[0006] The positioning procedure for DL-PRS measurements for RRC CONNECTED allows a limited level of intra-gNB mobility (within the coverage area of ​​a TRP belonging to the same gNB) and inter-gNB mobility (for scenarios where multiple gNBs use the same PRS configuration). Reporting of measurement or location information to the LMF is supported via the serving gNB / cell. Summary of the invention

[0007] A wireless transmit / receive unit (WTRU) may receive configuration information indicating a plurality of association sets. Each association set may include a plurality of corresponding time instances and a plurality of corresponding timing advance (TA) offsets. The WTRU may send an indication of at least one of a mobile network node identity or WTRU location information. The WTRU may receive an indication of a first association set of the plurality of association sets. The WTRU may begin sending a first sounding reference signal (SRS) for positioning (SRSp) transmission at a first time. The first time may be determined based at least on a first TA offset of the first association set and a first time instance associated with the first TA offset.

[0008] The first TA offset may be based on a first satellite TA offset. The WTRU may send the first SRSp transmission to a satellite corresponding to the mobile network node identifier or the WTRU location information. The first time may be a first TA value prior to the first time instance. The first TA value may be determined based on the first TA offset. The first TA value may be determined based on the sum of the first TA offset and the first WTRU TA offset. The first WTRU TA offset may be determined based on the first location of the WTRU. The first TA offset may be selected from the first association set based on the resources for the first SRSp transmission associated with the first time instance. The first TA offset may be selected based on the area in which the WTRU and / or the satellite is located. The configuration information may include an SRSp resource set. The first SRSp transmission may be sent using at least one resource in the SRSp resource set.

[0009] The WTRU may receive an indication of a second association set in the plurality of association sets. The WTRU may begin sending a second SRSp transmission at a second time. The second time may be determined based on at least a second TA offset of the second association set and a second time instance associated with the second TA offset. The second TA offset may be based on a second satellite TA offset. The second time may be preceded by a second TA value by the second time instance. The second TA value may be determined based on the second TA offset. The second TA value may be determined based on a sum of the second TA offset and a second WTRU TA offset. The second WTRU TA offset may be determined based on a second position of the WTRU or the first position of the WTRU.

[0010] Methods and apparatus for supporting positioning using a mobile access node are provided. Methods and apparatus for supporting DL-based positioning using a mobile access node are provided. Methods and apparatus for supporting UL-based positioning using a mobile access node are provided.

[0011] The WTRU may select an SRSp configuration (e.g., SRSp resource transmit power, periodicity, repetition factor) from a preconfigured candidate set based on determining a differential TA (e.g., the difference between the TA at the UE and the TA at the reference point) and / or a relative position of the WTRU relative to a mobile satellite for UL-based positioning with the mobile satellite. The WTRU may be configured to receive configuration information from a network. The WTRU may determine the differential TA based on the configuration information. If the differential TA is less than a predetermined threshold, the WTRU may select a first SRSp configuration (e.g., an SRSp with 2 repetitions). The WTRU may transmit an indication to the network requesting activation of the selected first SRSp configuration. Upon receiving an activation indication from the network and / or upon applying the TA offset to the SRSp at an associated transmit time instance, the WTRU may transmit the SRSp using resources in the first SRSp configuration. If the differential TA is greater than or equal to the predetermined threshold, the WTRU may select a second SRSp configuration (e.g., an SRSp with 8 repetitions). The WTRU may transmit an indication to the network requesting activation of the selection of the first SRSp configuration. Upon receiving the activation indication from the network and / or upon applying the TA offset to the SRSp at the associated transmission time instance, the WTRU may transmit the SRSp using resources in the second SRSp configuration.

[0012] The WTRU may perform one or more measurements (e.g., such as RSRP and / or ToA) of a PRS received from a mobile satellite based on a time difference (e.g., RSTD) calculation relative to a reference point on a cell / beam associated with the satellite. The WTRU may be configured to receive configuration information from the network. The WTRU may perform a first RSRP and / or first TOA measurement of a PRS received from a satellite at a first measurement time instance. If the measured RSRP is greater than or equal to an RSRP threshold and the measured TOA minus the expected TOA at the reference point is less than an RSTD threshold, the WTRU may perform a second RSRP and / or TOA measurement of the PRS at a second measurement time instance, and perform a third RSRP and / or TOA measurement of the PRS at the second measurement time instance using an alternate PRS configuration. If the measured RSRP is less than the RSRP threshold, the WTRU may select an alternative satellite and / or perform a second RSRP and / or TOA measurement of the PRS at the second measurement time instance using the alternate PRS configuration. The WTRU may report the first RSRP, the second RSRP and / or the third RSRP to the LMF and / or report TOA measurements to the LMF. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1Ais a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0014] Figure 1B is an example of a method that can be used according to an embodiment of the present invention. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system.

[0015] Figure 1C is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an example Radio Access Network (RAN) and an example Core Network (CN) for use within the illustrated communication system.

[0016] Figure 1D is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of another example RAN and another example CN for use within the illustrated communication system.

[0017] Figure 2 An example WTRU is depicted that performs measurements of a positioning reference signal (PRS) received from a mobile satellite.

[0018] Figure 3 An example determination of a measurement configuration for measuring a PRS received from a mobile access node is depicted.

[0019] Figure 4 Depicted is an example of switching from using a first satellite to using a second satellite based on a switching event.

[0020] Figure 5 An example measurement configuration determination based on a relative movement of a WTRU with respect to a movement threshold is depicted.

[0021] Figure 6 Depicted are example selections of Sounding Reference Signal (SRS) for positioning (SRSp) configurations for uplink-based positioning utilizing mobile satellites.

[0022] Figure 7 Depicts example round trip time (RTT) measurement configuration selections.

[0023] Figure 8 Another example selection of a Sounding Reference Signal (SRS) for positioning (SRSp) configuration for uplink-based positioning utilizing mobile satellites is depicted.

[0024] Fig. 9 Depicted is a flow chart for sending an uplink SRSp with a timing advance (TA). DETAILED DESCRIPTION

[0025] Figure 1A1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of 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 unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, and filter bank multi-carrier (FBMC), etc.

[0026] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should 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 may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to send and / or receive wireless signals and may include user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), consumer electronic devices, and devices operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as WTRUs.

[0027] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with one or more of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0028] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of a licensed spectrum and an unlicensed spectrum. A cell may provide coverage of wireless services to 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 the base station 114a may be divided into three sectors. Thus, in an example, the base station 114a may include three transceivers, for example, one transceiver for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0029] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0030] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0031] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0032] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0033] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0034] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0035] Figure 1A The base station 114b in may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), and roads. In an example, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.11) to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.15) to establish a wireless personal area network (WPAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0036] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the text and video, the CN 106 / 115 may be configured to provide voice, data, applications and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Figure 1AAlthough not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0037] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0038] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0039] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, 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 source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0040] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of 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) and state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0041] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from a base station via an air interface 116. In an example, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0042] Although the transmit / receive element 122 Figure 1B 102 as a single element, but the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. In an example, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for sending and receiving wireless signals over the air interface 116.

[0043] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0044] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, and a secure digital (SD) memory card, among others. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0045] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0046] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0047] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device and activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor; geolocation sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor and / or humidity sensor.

[0048] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (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 139 for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0049] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0050] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0051] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0052] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0053] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0054] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0055] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0056] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0057] Although the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may (eg, temporarily or permanently) employ a wired communications interface with a communications network.

[0058] In a representative embodiment, the other network 112 may be a WLAN.

[0059] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and destined for a target outside the BSS may be transmitted to the AP to be delivered to the corresponding target. Traffic between STAs within the BSS may be transmitted by the AP, for example, where the source STA may transmit traffic to the transmitting AP, and the AP may deliver traffic to the target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Direct link establishment (DLS) may be utilized to transmit point-to-point traffic between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0060] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0061] High throughput (HT) STAs may communicate using a 40 MHz wide channel (eg, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels) to form a 40 MHz wide channel.

[0062] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and the data can be sent by sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0063] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0064] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is sending to the AP, the entire available band may be considered busy even if most of the band remains idle and may be available.

[0065] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0066] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0067] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0068] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or Transmission Time Intervals (TTIs) of varying or scalable lengths (e.g., including varying numbers of OFDM symbols and / or varying absolute time lengths).

[0069] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while also not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeB 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0070] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b and routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0071] Figure 1DThe illustrated CN 115 may include one or more of AMFs 182a, 182b, one or more of UPFs 184a, 184b, one or more session management functions (SMFs) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0072] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling and mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0073] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0074] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may 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, and providing mobility anchoring, etc.

[0075] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0076] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein for one or more of the following items may be performed by one or more simulation devices (not shown): WTRU102a-102d, base station 114a-114b, evolved Node B 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-182ab, UPF 184a-184b, SMF 183a-183b, DN 185a-185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device can be used to test other devices and / or simulate network and / or WTRU functions.

[0077] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0078] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0079] A downlink positioning method, an uplink positioning method, and a downlink and uplink positioning method may be provided. In the downlink positioning method, a positioning reference signal (PRS) may be transmitted to the WTRU from multiple transmit-receive points (TRPs). The WTRU may observe multiple reference signals and may measure the time difference of arrival (TDoA) between a pair of PRSs. The WTRU may then transmit the measured reference signal time difference (RSTD) to the network (e.g., location management function (LMF)). In addition, the WTRU may transmit the measured reference signal received power (RSRP) for each PRS. Based on the returned measurement results, the LMF may perform positioning of the WTRU. Additionally or alternatively, the WTRU may report the RSRP for a downlink (DL) angle-based positioning method.

[0080] The LMF is a non-limiting example of a node or entity (eg, a network node or entity) that may be used for or support positioning. Any other node or entity may replace the LMF and still be consistent with the disclosure herein.

[0081] In the uplink positioning method, the WTRU may transmit a sounding reference signal (SRS) configured by the radio resource control (RRC) for positioning to the TRP. In the timing-based method, the TRP may measure the relative time of arrival (RTOA) for the received SRS and may report the measurement value to the LMF. The WTRU may report the RSRP of the SRS. In the angle-based uplink positioning method, the TRP may measure the angle of arrival and may report the angle of arrival to the LMF.

[0082] In the uplink and downlink positioning methods, the WTRU may measure the Rx-Tx time difference between the received PRS and the transmitted SRS. The WTRU may report the measured Rx-Tx time difference to the LMF. The WTRU may report the measured RSRP of the PRS. Similarly, at the TRP, the Rx-Tx difference between the received SRS and the transmitted PRS may be calculated.

[0083] A DL positioning method may refer to any positioning method that uses a downlink reference signal such as a PRS. The WTRU may receive multiple reference signals from a transmission point (TP) and may measure DL RSTD and / or RSRP. Examples of DL positioning methods may include DL Angle of Departure (AOD) (DL-AoD) positioning and / or DL ​​Time Difference of Arrival (TDOA) (DL-TDOA) positioning.

[0084] The UL positioning method may refer to any positioning method that uses an uplink reference signal such as an SRS for positioning. The WTRU sends an SRS to multiple RPs, and the RPs measure UL RTOA and / or RSRP. Examples of UL positioning methods are UL-TDOA or UL-AoA positioning.

[0085] DL and UL positioning methods may refer to any positioning method that uses both uplink reference signals and downlink reference signals for positioning. In an example, the WTRU may send SRS to multiple TRPs and the gNB measures the Rx-Tx time difference. The gNB may measure the RSRP of the received SRS. The WTRU may measure the Rx-Tx time difference of the PRS sent from multiple TRPs. The WTRU may measure the RSRP of the received PRS. The Rx-TX difference and / or RSRP that may be measured at the WTRU and the gNB may be used to calculate the round trip time. The Rx and Tx difference may refer to the difference between the arrival time of the reference signal sent by the TRP and the transmission time of the reference signal sent from the WTRU. An example of a DL and UL positioning method is multi-RTT positioning.

[0086] The network as used in this article may include AMF, LMF, base station, TRP and / or gNB in ​​NG-RAN.

[0087] The positioning procedure for DL-PRS measurements for RRC CONNECTED allows a limited level of intra-gNB mobility (within the coverage area of ​​a TRP belonging to the same gNB) and inter-gNB mobility (for scenarios where multiple gNBs use the same PRS configuration). Reporting of measurement or location information to the LMF is supported via the serving gNB / cell.

[0088] As used herein, a mobile access node may include one or more satellites, base stations, TRPs and / or gNBs in NG-RAN, IAB nodes, relay nodes, drones, robots, positioning reference units (PRUs), and / or WTRUs (e.g., anchor WTRUs, reference WTRUs). A mobile access node may be mobile (e.g., moving in a certain direction and / or at a certain speed) relative to one or more stationary or mobile WTRUs and / or other network nodes (e.g., TRPs, gNBs).

[0089] WTRU-based and LMF-based (e.g., WTRU-assisted) positioning may be provided for RAT-dependent positioning procedures and RAT-independent positioning procedures. The WTRU behaviors and procedures for supporting positioning in a terrestrial network (TN) or a non-terrestrial network (NTN), including one or more steps in any given positioning procedure, not limited to reception of a broadcast channel, configuration, sending / receiving of an initial access message, sending / receiving of positioning signals, measurements and reporting, which may be supported by a WTRU with low latency, high reliability, high power savings and high accuracy, are unknown. Procedures and signaling for positioning are supported via the LTE Positioning Protocol (LPP), including sending and receiving capability information, assistance data, requests for location information and measurement reports. LPP procedures and signaling may be used to determine WTRU positioning information using a mobile access node / TRP.

[0090] In NTN scenarios, satellites (e.g., LEO satellites) may be highly mobile relative to a WTRU located on the surface of the Earth. Similarly, in Industrial Internet of Things (IIoT) or public safety scenarios, drones or robots may move on certain trajectories. In these scenarios, based on a positioning service request / requirement (e.g., LCS request), when at least a subset of access nodes (e.g., NTN satellites, TRPs, drones, relay nodes) are mobile, the WTRU may be positioned with relatively high accuracy (e.g., <1m horizontal / vertical accuracy).

[0091] In the DL-based positioning method, the WTRU performs measurements of resources associated with the DL-PRS and transmits measurement reports to the LMF based on assistance data provided by the network. In the UL-based positioning method, the WTRU is configured with SRS (SRSp) resources for positioning via RRC signaling. The transmission of SRSp by the WTRU is then received by different TRPs / gNBs in the network for performing positioning measurements and reporting the measurements to the LMF and determining the WTRU position. Such positioning procedures may be performed by the WTRU and / or the network whenever the position of the access node relative to the WTRU changes due to the use of mobile access nodes, and such positioning procedures may allow the position of the WTRU to be determined with a certain accuracy.

[0092] Having to perform a lengthy positioning procedure every time to transmit any assistance data or initiate any positioning procedure may result in unnecessary overhead, increased latency, and loss of power efficiency. Additionally, since the WTRU may be stationary or mobile relative to a mobile satellite or TRP, it is challenging to perform positioning of the WTRU using mobile access nodes / satellites with high accuracy and low overhead.

[0093] In this regard, a key issue to be addressed is: how to support positioning of the WTRU efficiently and with high accuracy when one or more of the access nodes (e.g., satellite, TRP) are mobile?

[0094] As used herein, SRS for positioning may refer to an SRS signal / transmission for positioning. Resources of SRS for positioning (SRSp) may be defined (eg, signaled) by RRC. An SRS resource set and SRS resources configured for positioning may be provided. As used herein, "SRS for positioning" and / or "SRS" may include: SRS configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; SRS configured under SRS-ResourceSet and SRS-Resource; SRS not configured under SRS-PosResourceSet-r16 and SRS-PosResource-r16; SRS not configured under SRS-ResourceSet and SRS-Resource; SRS not associated with SRS-PosResourceSet-r16, SRS-PosResource-r16, SRS-ResourceSet or SRS-Resource; associated uplink reference signal for positioning; DM-RS for uplink; and / or PTRS for uplink.

[0095] The SRS used for positioning may be denoted herein as “SRSp.” PRS and SRS as used herein are not limited to RS used for positioning. The methods herein may be applied to or may be used with any DL or UL reference signal.

[0096] The positioning configuration may include a set of information related to positioning measurements and / or SRSp transmission. The positioning configuration may include one or more of the following: the positioning method used (e.g., DL-TDOA, UL-TDOA, DL-AoD, UL-AoA, multi-RTT), PRS configuration, SRSp configuration, uplink resources used to report positioning measurements (e.g., PRACH, PUSCH, PUCCH), one or more thresholds for determining the quality of positioning measurements, and / or a positioning operation mode (e.g., start positioning operation mode). The PRS resource configuration may include one or more of the following: a PRS resource ID, a PRS sequence ID or other ID used to generate a PRS sequence, a PRS resource element offset, a PRS resource slot offset, a PRS symbol offset, PRS QCL information, a PRS resource set ID, a list of PRS resources in a resource set, the number of PRS symbols, a muting mode and / or muting parameters for PRS, such as a repetition factor, a muting option, a PRS resource power, a periodicity of PRS transmission, spatial direction information of PRS transmission (e.g., beam information, transmission angle), spatial direction information of UL RS reception (e.g., beam ID for receiving UL RS, angle of arrival), frequency layer ID, TRP ID and / or PRS ID.

[0097] The SRSp resource configuration may include one or more of the following: resource ID, comb offset value, cyclic shift value, starting position in the frequency domain, number of SRSp symbols, shift in the frequency domain of SRSp, frequency hopping mode, type of SRSp (e.g., non-periodic, semi-persistent or periodic), sequence ID for generating SRSp or other ID for generating SRSp sequence, spatial relationship information (e.g., indicating which reference signal (e.g., DL RS, UL RS, CSI-RS, SRS, DM-RS) or SSB (e.g., SSB ID, cell ID of SSB) the SRSp is spatially related to), QCL information (e.g., QCL relationship between SRSp and other reference signals or SSBs), QCL type (e.g., QCL type A, QCL type B, QCL type D), resource set ID, list of SRSp resources in the resource set, transmit power related information, path loss reference information (which may include indexes of SSB, CSI-RS or PRS), periodicity of SRSp transmission, spatial direction information of SRSp transmission (e.g., beam information, transmit angle), DL Spatial direction information of RS reception (e.g., beam ID and arrival angle for receiving DL RS).

[0098] As part of its configuration, the WTRU may receive information related to the cell ID, the global cell ID, and / or the TRPID associated with the PRS. For example, the TRP transmitting the PRS may be identified by the TRP ID, which may belong to the cell identified by the cell ID. The WTRU may be configured with timing information such as the SFN offset for PRS or SRSp transmission. The offset may prevent the WTRU from receiving overlapping PRS in the time domain.

[0099] The WTRU may obtain parameters or configurations related to SRSp or SRS in RRC, MAC-CE, DCI, or LPP messages. Alternatively, the WTRU may obtain parameters, configurations, or thresholds related to SRSp or SRS (e.g., thresholds for RSRP) in a broadcast message (e.g., SIB) or in dedicated signaling for the WTRU from the network.

[0100] SRS and SRSp may be used interchangeably herein. Mobile access node, mobile TRP / gNB, satellite and / or NTN node may be used interchangeably herein when referring to any network node or WTRU that is movable relative to a target WTRU that may be positioned. The target WTRU may be stationary or relatively mobile relative to a mobile access node / satellite that may be used for positioning. The target WTRU may perform PRS measurements and / or SRSp transmissions from / to a mobile access node / satellite during positioning.

[0101] In an example, the relative positioning of the NTN nodes changes for a fixed WTRU on the surface of the Earth as the NTN satellites / nodes orbit the Earth. By considering the NTN nodes at different time instances as virtual TRPs, it is possible to apply DL / UL based positioning methods with some modifications.

[0102] For DL-based positioning with NTN satellites, the WTRU may measure DL signals (e.g., PRS) received from one or more mobile satellites (e.g., LEO, MEO satellites) at different time instances / opportunities based on the trajectory / ephemeris data (e.g., NTN node orbit) and orbital velocity that the satellites are expected to follow.

[0103] For UL-based positioning, the WTRU may send UL signals (e.g., SRSp) that may be measured by one or more mobile satellites when triggered by an event (e.g., a scheduled opportunity aligned with a satellite trajectory). For example, the benefits of using mobile satellites for positioning may include improved measurement efficiency due to the use of a minimal amount of BW and / or number of TRPs / nodes used for positioning, lower overhead due to minimal (per satellite) assistance data (e.g., PRS / SRSp configuration), and improved robustness against radio environment changes (e.g., blockages may be avoided, NLOS paths may be avoided).

[0104] When performing measurements of DL signals received from a single mobile NTN node, it is important that the WTRU measures the DL signals at time instances that take into account satellite trajectory / ephemeris data, orbital velocity, positioning errors, corrections / biases, etc. This is to ensure positioning accuracy and avoid dilution of precision (DOP) issues (e.g., the NTN node / TRP has not moved sufficiently between different measurement occasions). Similar issues arise for UL based positioning, where it is important that the WTRU performs transmission of UL signals at time instances that take into account satellite trajectory / ephemeris data, orbital velocity, positioning errors, corrections / biases (e.g., TA), etc.

[0105] In an example, the WTRU and / or network may use more than one track corresponding to one or more satellites to perform accurate measurements of time difference of arrival (TDOA) relative to a reference time of arrival (ToA) measurement. The WTRU / NW may determine a virtual TRP based on the tracks and velocities of the satellites (e.g., for a given track of a single satellite, measurements taken at 5 second intervals may be considered as measurements from different satellites). In this case, for example, timestamps may be used to correlate the measurements. For example, the WTRU may indicate which measurement (associated with a timestamp) is used as a reference measurement.

[0106] A WTRU may be provided with assistance data for a set of one or more satellites (e.g., NTN satellites) with known trajectory / ephemeris data (e.g., the WTRU knows the expected positions of the satellites for positioning at different time instances / occasions), for example, to support positioning using mobile satellites. For example, a time window may also be provided to the WTRU, which indicates the time instance and / or duration for performing positioning measurements / transmissions from / to the mobile satellites. In an example, the WTRU may receive assistance data for a combination of satellite trajectories and the expected time of the start / end of measurements for each trajectory. The WTRU may follow a sequence of time windows for measurements. For example, the reason for this is that once a satellite sinks below the horizon, the WTRU no longer performs measurements / transmissions from / to the satellite. In an example, for a single mobile satellite, the WTRU may periodically perform measurements with a periodicity value corresponding to the measurement time window.

[0107] In an example, the WTRU may have the option of selecting a combination of fixed satellites (e.g., geostationary satellites) and mobile satellites (e.g., LEO satellites) for positioning. This selection may be made based on configured criteria to ensure high accuracy, low latency, etc. For example, the WTRU may determine which satellites to use (e.g., mobile satellites and / or geostationary satellites) based on a measurement time window and an inter-measurement separation criterion. For example, if the WTRU cannot observe enough mobile satellites that may overlap in the time window, the WTRU may rely on multiple geostationary satellites for positioning.

[0108] The WTRU may initiate positioning using a mobile access node. In an example, the WTRU may be triggered to initiate one or more positioning procedures (e.g., DL-based positioning procedures, UL-based positioning procedures) using one or more access nodes (e.g., satellites, TRPs), where one or more of the access nodes / satellites may be mobile. Positioning of a WTRU (e.g., a target WTRU) using one or more mobile nodes may be initiated based on the triggering and / or reception of an LCS message. For example, an LCS client in the WTRU (e.g., for MO-LR) or in the network / LMF (e.g., MT-LR) may trigger a request for the WTRU's location information along with an implicit or explicit indication to use one or more mobile TRPs / satellites to position the WTRU. In an example, the LCS client / network may explicitly indicate that positioning of the WTRU is performed using a satellite / drone.

[0109] In an example, the LCS client / network may implicitly indicate the use of mobile TRP / satellite (when available), for example, when indicating relaxed latency requirements for positioning. Additionally or alternatively, the LCS client / network may implicitly indicate the use of mobile TRP / satellite, for example, when providing expected trajectory information (e.g., ID, assistance data) of the mobile TRP / satellite and / or the scheduled position of the TRP / satellite at one or more time instances together with the LCS request for positioning the WTRU.

[0110] Positioning of a WTRU (e.g., a target WTRU) using one or more mobile nodes may be initiated based on receiving an LPP request / indication. For example, a WTRU with an ongoing LPP session may receive an indication / configuration information to include one or more mobile TRPs / satellites in positioning measurements when the mobile TRP is within range of the WTRU (e.g., the WTRU is able to detect any SSB / PRS transmissions from the mobile TRP).

[0111] In an example, when some mobile TRPs / satellites are available / detectable to the WTRU, the WTRU may receive an indication from the network (e.g., LMF, gNB) to switch to and / or initiate / activate a different positioning session (e.g., a new LPP session). For example, such an indication may be received by the WTRU based on an indication / message transmitted by the WTRU to the network notifying any of: an initial WTRU position, an initial measurement of PRS / SSB / CSI-RS, an initial estimate of a timing advance (TA) value, and / or a detection of one or more mobile access nodes / TRPs / satellites (e.g., IDs).

[0112] Positioning of a WTRU (e.g., a target WTRU) using one or more mobile nodes may be initiated by the WTRU. For example, positioning using satellites may be initiated by the WTRU when the WTRU is within the coverage of any of the satellites and / or detects a PRS transmitted by a satellite.

[0113] In an example, a WTRU that is pre-configured with some initial PRS configuration may use the configuration to detect satellites that may continuously or periodically transmit PRS (e.g., similar to GNSS signals). The WTRU may perform initial measurements of PRS using the pre-configured PRS configuration associated with the satellite. For example, if the PRS measurement meets certain criteria / conditions (e.g., the ToA / RSRP of the PRS is above a threshold and / or remains above a threshold for some duration), the WTRU may report the WTRU's PRS measurement or position estimate to the network.

[0114] The WTRU may select an SRSp configuration (e.g., SRSp resource transmit power, periodicity, repetition factor) from a preconfigured candidate set based on determining a differential TA (e.g., the difference between the TA at the WTRU and the TA at a reference point) and / or a relative position of the WTRU relative to a mobile satellite for UL-based positioning with the mobile satellite. The WTRU may be configured to receive configuration information from a network. The WTRU may determine the differential TA based on the configuration information. If the differential TA is less than a predetermined threshold, the WTRU may select a first SRSp configuration (e.g., an SRSp with 2 repetitions). The WTRU may transmit an indication to the network requesting activation of the selected first SRSp configuration. Upon receiving an activation indication from the network and / or upon applying the TA offset to the SRSp at an associated transmit time instance, the WTRU may transmit the SRSp using resources in the first SRSp configuration. If the differential TA is greater than or equal to the predetermined threshold, the WTRU may select a second SRSp configuration (e.g., an SRSp with 8 repetitions). The WTRU may transmit an indication to the network requesting activation of the selection of the first SRSp configuration. Upon receiving the activation indication from the network and / or upon applying the TA offset to the SRSp at the associated transmission time instance, the WTRU may transmit the SRSp using resources in the second SRSp configuration.

[0115] As described herein, the WTRU may communicate capabilities and / or assistance information to a network (e.g., a gNB or LMF) for use in performing positioning measurements and / or transmissions using one or more mobile access nodes based on detection of one or more triggering events.

[0116] For example, the WTRU may semi-statically transmit the capability / assistance information before / after initiating a positioning procedure (e.g., LPP session) for determining the location of the WTRU. Additionally or alternatively, the WTRU may dynamically or on-demand transmit the capability / assistance information, for example, at any given time after initiating a positioning procedure involving a mobile access node. The WTRU may transmit the capability / assistance information to the network in an LPP message (e.g., LPP Provide Capability Information or LPP Provide Assistance Information message) or AS layer signaling / messages (e.g., RRC, MAC CE, UCI, PUSCH).

[0117] The information transmitted by the WTRU to the network, whether as capability information (e.g., via an LPP capability transfer procedure, AS layer signaling / messages) or assistance information (e.g., via an LPP assistance data transfer procedure, AS layer signaling / messages), may include one or more methods applied when using mobile access nodes. The one or more methods may include the ability to operate in a WTRU-assisted mode and / or a WTRU-based mode when using mobile access nodes. For example, when operating in a WTRU-based mode, the WTRU may indicate the ability to estimate the location of the WTRU when at least a subset of one or more access nodes are mobile.

[0118] The one or more methods may include a node type. For example, the WTRU may indicate one or more identifiers / information associated with a mobile access node (e.g., a satellite, an NTN node, a TRP / gNB, a PRU), which may be used to perform positioning measurements and / or transmissions.

[0119] The one or more methods may include techniques and / or algorithms.For example, the WTRU may indicate an identifier / information regarding a positioning technology (eg, TDoA, AoD, RTT) used with a mobile access node to estimate the WTRU's position.

[0120] The one or more methods may include device attributes and / or parameters. For example, the WTRU may provide information about the number of antenna elements / panels, the number of RF chains (e.g., for GNSS, for non-GNSS), antenna configuration information, supported bandwidth (e.g., per RF chain), and processing capabilities for sending / receiving and fusion RF and timing measurements and / or GNSS-PRS measurements.

[0121] One or more methods may include achievable accuracy. For example, the WTRU may provide one or more levels of positioning accuracy that can be achieved when using a mobile access node (e.g., per antenna element / panel, per Rx / Tx RF chain). The WTRU may indicate information about a timing error group (TEG), including, for example, a WTRU Tx TEG ID, a WTRU Rx TEG ID, a WTRUx-Tx TEG ID. For example, the WTRU may also transmit association information between an SRSp resource and a WTRU Tx TEG ID. The WTRU may indicate whether it is possible to perform measurements of GNSS signals and non-GNSS signals (e.g., PRS received from GEO, MEO and / or LEO satellites) simultaneously. In an example, when measurements of GNSS signals and non-GNSS signals (e.g., PRS) are combined, the WTRU may indicate an increase in accuracy. When using GNSS measurements and non-GNSS measurements, the WTRU may also indicate a priority value and / or a preferred value.

[0122] The one or more methods may include one or more signal measurements and / or estimates. For example, the WTRU may provide information about measurements made on GNSS signals and / or non-GNSS signals (such as PRS) (e.g., time of arrival (ToA), timestamp, RSRP, RSTD measurements).

[0123] In an example, the WTRU may provide information about a timing advance / alignment (TA) value measured / estimated by the WTRU. For example, such estimation of TA may be associated with a WTRU-specific TA value and / or may be performed by the WTRU based on measurements of GNSS signals, an estimate of the WTRU's position, and / or assistance data received from the network (e.g., common or cell / beam-specific TA).

[0124] Positioning of a WTRU (e.g., a target WTRU) using one or more mobile nodes may be initiated based on an initial position and / or a reference position and / or trajectory. For example, the WTRU may provide information (e.g., identifiers) regarding the availability / accessibility of one or more reference positions associated with a positioning reference unit (e.g., a WTRU, a TRP, a gNB, a cell, an NTN node, a geostationary satellite), any detectable landmarks or reference points (e.g., associated with a common / cell-specific TA value) that may be in the vicinity of the WTRU. For example, the WTRU may also provide a distance / range to the identified reference position.

[0125] In an example, the WTRU may provide information about GNSS nodes, NTN nodes, or satellites (e.g., IDs) that the WTRU may detect in one or more time windows. For example, the WTRU may provide information about initial measurements made on signals received from reference satellites (e.g., ToA and / or RSRP measurements with timestamps). For example, the WTRU may also provide trajectory information of detectable reference satellites (e.g., based on known trajectory IDs or ToA / RSRP measurements and associated timestamps).

[0126] For example, the WTRU may also indicate information (e.g., IDs) regarding one or more positioning areas and / or zones, which may be associated with coverage areas of one or more cells / beams / satellites / TRPs / gNBs in which the WTRU was previously located, is currently located, and / or is expected to be located at different time instances.

[0127] Positioning of a WTRU (e.g., a target WTRU) using one or more mobile nodes may be initiated based on information about power saving modes. For example, power saving modes supported by the WTRU and / or configured by the network may be provided, which may include timing information (e.g., timestamps) for when the WTRU has previously transitioned to or is expected to transition to RRC CONNECTED, RRC INACTIVE, RRC IDLE, or any other combination of power saving modes / states.

[0128] For example, the information about the power saving mode may include one or more preferred configurations or preferred parameters associated with CDRX / DRX (eg, cycle time on duration, inactivity timer duration).

[0129] For example, the WTRU may also indicate priority values ​​and / or preference values ​​associated with supported power saving modes / states, possibly together with location / area information and / or timing information regarding where / when such priority / preference values ​​may apply.

[0130] The triggering events / conditions monitored by the WTRU for transmitting capability information and / or assistance information using a mobile access node may include receiving an indication or LCS / LPP request from a higher layer / application / network. For example, when triggered by an LCS client / application in the WTRU (e.g., MO-LR) or in the network (e.g., MT-LR, delayed MT-LR, NI-LR), the WTRU may transmit information / indications. In this case, for example, the LCS client may provide a reference time (e.g., a scheduled position time, including one or more time instances for requesting the WTRU's position) and / or a reference / initial position (e.g., satellite, TRP, PRU). The WTRU may receive an indication from the LCS client in any of the following: an LCS message, an LPP message, an AS layer signaling / channel (e.g., RRC, MACCE, DCI, data).

[0131] In an example, the WTRU may transmit capability / assistance information upon receiving an LPP request message (e.g., a request for capability information) from the network. The request message may include a request for information related to measurements (e.g., GNSS, non-GNSS), the ability to support / perform positioning using mobile satellites / TRPs, WTRU power saving modes, trajectories, reference positions / times, accuracy attributes, etc.

[0132] The triggering events / conditions monitored by the WTRU for transmitting capability information and / or assistance information using a mobile access node may include detecting a reference position and / or time. For example, the WTRU may transmit information / indications when one or more reference / initial positions (e.g., satellite, TRP, PRU, positioning area) are detected and / or at a reference time instance (e.g., scheduled position time).

[0133] The triggering events / conditions monitored by the WTRU for transmitting capability information and / or assistance information using the mobile access node may include event-triggered and / or periodic. For example, the WTRU may transmit information / indications periodically, which may be based on one or more periodicity values ​​configured by the network. In an example, the WTRU may transmit updated / new capability / assistance information when any change in capability / assistance information relative to a previous opportunity at which the information may be transmitted is detected.

[0134] The triggering events / conditions monitored by the WTRU for transmitting capability information and / or assistance information for using the mobile access node may include changes in radio conditions, positioning measurements and / or positioning errors. For example, the WTRU may transmit information / indications when triggered by changes in radio conditions detectable at the WTRU. In an example, a WTRU configured to perform measurements of DL-PRS / CSI-RS / SSB / GNSS signals or estimates of TA values ​​(e.g., WTRU-specific TA) may transmit information when the measured values ​​(e.g., RSRP, RSD, ToA, RSSI) increase / decrease by certain corresponding thresholds.

[0135] The WTRU may transmit any indication / information to the network (e.g., gNB, LMF), which may be based on one or more of the triggering events and / or conditions described herein. The indication / information transmitted by the WTRU may include capability information, a request for assistance data (e.g., trajectory / ephemeris data of a mobile access node / satellite), a request for a new / updated SRSp / PRS configuration, a request to activate / deactivate a pre-configured SRSp / PRS configuration, an indication to notify the start of SRSp transmission or the start of PRS measurement, and / or detection of an indication of a triggering event (e.g., detection of a satellite, mobile TRP, identification of a matching trajectory of a satellite / mobile TRP, detection of an error during measurement).

[0136] In an example, when using one or more access nodes that are mobile, the WTRU may receive assistance data and / or configuration information for supporting positioning procedures and / or methods (e.g., DL-based, UL-based, DL+UL-based, GNSS). The assistance data may be received in a positioning SIB (e.g., broadcast in a posSIB with a configured periodicity), an LPP message, or an AS layer signaling / channel (e.g., RRC, MAC CE, DCI, PDSCH). For example, the assistance data and / or configuration information may be received by the WTRU from an LMF (e.g., via LPP), a gNB (e.g., RRC signaling / messages), and / or an access node / satellite (e.g., via AS layer signaling).

[0137] The WTRU may receive assistance data / configuration information associated with a mobile access node due to one or more triggers. The one or more triggers may include a transmission request. For example, the WTRU may transmit a request for assistance data (e.g., LPP message on-demand SI, AS layer signaling) to the network, the assistance data indicating information / identifiers / configuration / parameters associated with one or more mobile access nodes. The WTRU may then receive the corresponding assistance data. In an example, the WTRU may receive the assistance data (e.g., in an LPP message) after transmitting the capability information and / or any other indication / message (e.g., on-demand request, LCS message, LPP message, positioning information / report).

[0138] The WTRU may periodically receive assistance data / configuration information associated with a mobile access node. For example, the WTRU may be configured by the network to periodically receive assistance data with a certain configured periodicity. For example, the WTRU may request a change in the periodicity for receiving assistance data based on detecting one or more events such as a change of satellite, detecting a change in the mobility state of a mobile access node / satellite, detecting a change in the mobility state of the WTRU (e.g., from a stopped state to a moving state), detecting a change in the trajectory of a satellite, etc.

[0139] One or more triggers may include detection of one or more configured events and / or conditions. For example, the WTRU may receive one or more assistance data associated with a mobile access node and / or a positioning method / scheme (e.g., PRS configuration). For example, the WTRU may store the assistance data and retrieve it for a future positioning procedure / session (e.g., LPP session). The WTRU may also receive validity conditions (e.g., positioning area, time, and / or trajectory validity) and / or events associated with storing / using / releasing the assistance data. In this case, the WTRU may use the pre-configured assistance data as long as the validity conditions are valid and / or the WTRU does not detect an event that invalidates the pre-configured assistance data.

[0140] In an example, when a validity condition expires and / or the WTRU detects an event that invalidates the pre-configured assistance data (possibly based on a report transmitted by the WTRU to the network indicating the expiration of the validity condition, the detection of the event and / or the request for new / updated assistance data), the WTRU may receive updated / new assistance data.

[0141] The assistance data and / or configuration received by the WTRU may include identifiers, indices, and / or tags. For example, the WTRU may receive an ID / index of one or more access nodes together with an indication / tag indicating the mobility state of the access node. For example, fixed / stationary access nodes and mobile access nodes may be indicated by different tag values. In examples where a mobile access node may experience different mobility states at different time instances / durations (including moving at a fixed speed, stopping, resuming movement, increasing / decreasing speed, etc.), the WTRU may receive information about one or more mobility states of the access node, possibly together with the time instances / durations when the mobility state changes or is expected to change.

[0142] The assistance data and / or configuration received by the WTRU may include one or more measurement / transmission time instances and / or time windows. For example, the WTRU may receive information at one or more measurement / transmission time instances (e.g., t0, t1, t2, ..., ti) indicating the time slots / opportunities at which the WTRU may perform PRS measurements and / or SRSp transmissions. For example, any of the time instances may be associated with a start offset time slot (e.g., ti-T1, corresponding to the earliest time slot for starting positioning measurements / transmissions), a duration (e.g., number of time slots), and a stop offset time slot (e.g., ti+T2, corresponding to the latest time slot for stopping positioning measurements / transmissions). The separation duration between different time instances may be configured to be fixed or variable. For example, in the case where the duration between time instances is fixed, the WTRU may periodically perform positioning measurements / transmissions with a fixed periodicity.

[0143] In an example, the time instances may correspond to spatial / positional separations of mobile access nodes / satellites from one instance to another, which may be traveling at a particular speed and / or on a trajectory / orbit.

[0144] For example, the WTRU may receive one or more time windows indicating the duration of the positioning that the WTRU may perform PRS measurements and / or SRSp transmissions from / to a mobile access node / satellite. In an example, the duration of the time window may correspond to the maximum delay for determining the WTRU position based on PRS measurements and / or SRSp transmissions.

[0145] In an example, the WTRU may receive a combination of one or more trajectories of a mobile access node, possibly associated with different measurement time windows and / or different expected measurement start / end times for each trajectory. For example, the start / end time for measurement may be indicated as a differential / offset value relative to a reference start / end time. For example, when using multiple mobile access nodes for positioning, the WTRU may sequentially use different associated time windows for measurement.

[0146] For example, the measurement time instance and / or time window may be identified by an ID / index and / or may be associated with one or more mobile access nodes used by the WTRU for positioning.

[0147] In an example where a WTRU may be configured for multiple round trip time (RTT) positioning with one or more mobile access nodes, the WTRU may receive an RTT configuration that includes a set of time instances for performing PRS measurements and a set of time instances for performing SRSp transmissions. For example, the time instances corresponding to the PRS measurements and the SRSp transmissions may be separated by a specific time duration that may be aligned with a trajectory and / or mobility attributes (e.g., velocity) of an access node / satellite.

[0148] The assistance data and / or configuration received by the WTRU may include separation criteria. In an example, the WTRU may treat the mobile access node / satellite as a separate TRP / node at different measurement time instances based on multiple factors including the trajectory of the mobile node, speed (e.g., orbital speed), movement direction / orientation of the node / cell / beam relative to the direction / position of the WTRU, etc.

[0149] For example, given a velocity value of a mobile node (e.g., a satellite), the WTRU may treat the mobile node as a separate node at different time instances when the time instances are separated by at least a certain time duration and / or may correspond to a spatial separation of the nodes by at least a certain distance. The distance may be associated with any of the following: horizontal distance, vertical distance (e.g., altitude when considering a satellite or a drone), orbital / angular distance / length on an orbital arch or orbital segment, etc.

[0150] For example, the separation criteria may be associated with separation based on a duration of time (e.g., between at least two measurements) and / or distance (e.g., movement of a node / satellite from one location to another). The WTRU may receive from the network (e.g., LMF, gNB) separation criteria for selecting a mobile access node / satellite for positioning and / or for determining when to perform measurements / transmissions from / to the selected mobile node / satellite. The one or more separation criteria received by the WTRU may be associated with any of: an ID / index, a mobile access node / satellite, one or more gNBs / TRPs, a PRS configuration, and an SRSp configuration.

[0151] In an example, any positioning measurements and / or transmissions performed by the WTRU in an intermediate duration and / or distance within the separation criteria may be considered as repetitions. For example, when a separation criterion is configured that instructs the WTRU to perform PRS measurements separated by a duration of at least Tms (e.g., a first PRS measurement and a second PRS measurement may be performed by the WTRU Tms apart), any PRS measurements performed within Tms may be considered as repetitions. When the measurements and / or transmissions are performed within the separation criterion, the WTRU and / or the network may consider PRS measurements and / or SRSp transmissions as repetitions. For example, such repetitions for PRS measurements and / or SRSp transmissions may be performed periodically and / or upon detection of a triggering event (e.g., ToA and / or RSRP of PRS is below / above a threshold), possibly to improve positioning accuracy.

[0152] In an example, a WTRU may be configured with measurement instances. The WTRU may receive the periodicity of the measurement instances from the network. In each measurement instance, the WTRU may measure the PRS (e.g., RSRP, RSTD, ToA, AoA) transmitted by the satellite. The WTRU may determine the measurement periodicity based on the configured separation criterion and / or the number of repeated measurements. The separation criterion may be indicated by the network based on the measurement instance. For example, when the separation criterion is L measurement instances, it indicates that when the WTRU measures at every L measurement instance, the measurement is considered unique (e.g., the correlation between two consecutive measurements is low enough). The number of repeated measurements may be the number of measurements within a predefined interval. Repeated measurements may be used to accumulate measurements so that averaging of measurements (e.g., an average value of RSRP) may be performed at the WTRU and / or the network. The WTRU may be configured to perform K repeated measurements. In an example, the WTRU may be configured to perform K repeated measurements within a window of L measurement instances. In an example, the WTRU may be configured to aggregate K measurements collected at every L measurement instances. The WTRU may indicate the aggregated measurement to the network by associating a flag with the aggregated measurement.The WTRU may determine to make K measurements within a window of L measurement instances or an aggregated measurement based on one or more of the following conditions.

[0153] Is K less than or equal to L. If the condition is met, the WTRU makes K measurements within a window of L measurement instances. If K is greater than L, the WTRU determines to aggregate K measurements measured at every L measurement instances.

[0154] Latency requirement for positioning: If the latency requirement for positioning is less than a threshold, the WTRU makes K measurements within a window of L measurement instances. If the requirement is greater than or equal to the threshold, the WTRU makes K measurements that the WTRU determines to aggregate at every L measurement instances.

[0155] The assistance data and / or configuration received by the WTRU may include a positioning configuration. For example, the WTRU may receive one or more PRS configurations / resources (e.g., IDs) and / or SRSp configurations / resources that may be associated with / intended for positioning using one or more mobile access nodes.

[0156] The PRS / SRSp configuration may include one or more frequency layers, resources, resource sets, beams, and / or access nodes / TRPs / satellites associated with the indicated PRS / SRSp configuration. For example, one or more PRS / SRSp configurations associated with a satellite may include a combination of a relatively low / high number of frequency layers, bandwidth (e.g., frequency resources), periodicity, resource density, number of beams, etc.

[0157] The PRS / SRSp configuration received by the WTRU may be associated with one or more trajectories applicable to the mobile access node used by the WTRU for positioning. For example, when the selected mobile access node / satellite follows a first trajectory, the WTRU may use a first PRS configuration (e.g., for PRS measurements). For example, when the mobile access node / satellite follows a second trajectory, the WTRU may switch to a second PRS configuration.

[0158] For example, the types of PRS / SRSp configurations received by the WTRU may include aperiodic, semi-persistent, periodic along with timing information associated with the different types, such as start time / slot, periodicity, and stop time / slot.

[0159] In an example where the WTRU may be configured for multi-round trip time (RTT) positioning with one or more mobile access nodes, the WTRU may receive both a PRS configuration and an SRSp configuration.

[0160] For example, the WTRU may also receive information (e.g., ID) about one or more measurement gap configurations, which may be associated with a PRS configuration to be used during the measurement. For example, such measurement gap configurations may be aligned with measurement time instances and / or activated during the measurement.

[0161] The assistance data and / or configuration received by the WTRU may include trajectory / ephemeris data of mobile access nodes / satellites. For example, the WTRU may receive trajectory information associated with one or more mobile access nodes / satellites that the WTRU may use for positioning.

[0162] In an example, the trajectory / ephemeris information may correspond to one or more points in space (e.g., position coordinates, absolute positions, or relative positions relative to a reference position / point) associated with a location where a mobile access node / satellite may be located (e.g., time 1: position 1, time 2: position 2, time 3: position 1).

[0163] In an example, the location information and / or trajectory information of a mobile access node / satellite may be associated with one or more accuracy / reliability values. For example, such accuracy / reliability may be indicated to the WTRU in the form of horizontal / vertical positioning accuracy values ​​(e.g., <1 cm, <1 m), confidence intervals, probability that the access node is located within an area / zone, integrity (e.g., protection level / limit, alarm limit), etc. For example, such accuracy / reliability values ​​corresponding to the location / trajectory information may be indicated to the WTRU to assist the WTRU in selecting a mobile access node for positioning and / or calculating its location information.

[0164] In an example, when it is determined that the pre-configured trajectory information is invalid, the WTRU may transmit a request message for updated trajectory information for the mobile access node / satellite. When using one or more mobile access nodes for positioning, the WTRU may request and / or receive information about a relevance time or validity time, which indicates how long the trajectory / ephemeris data of the mobile access node may be valid. When using one or more geostationary satellites for positioning, the WTRU may also request and / or receive information about a validity time, which indicates how long the geostationary satellites may be valid.

[0165] In an example, a known trajectory may include different sub-trajectory types / components (e.g., straight path, orbital path, left turn, right turn), which may be associated with different measurement time instances. The trajectory / ephemeris information may be associated with one or more PRS / SRSp configurations that may be used by the WTRU to perform measurements / transmissions when corresponding positions and / or time instances are detected.

[0166] In an example, a WTRU may receive one or more trajectories (e.g., preconfigured), wherein each trajectory or subset of trajectories may be associated with an ID and / or information about which trajectory / which subset of trajectories a mobile access node may desire to use / follow at different time instances / windows. When selecting a mobile access node / satellite for positioning and / or reporting information about an actual / estimated trajectory followed by a selected mobile access node, the WTRU may transmit information about the trajectory / subset of trajectories (e.g., ID / index) to the network. For example, in the event that there may be uncertainty in a current or expected trajectory (trajectory / subset of trajectories) followed by a mobile access node, the WTRU may determine one or more trajectories that may best match the preconfigured trajectories received from the network (e.g., the difference between the preconfigured trajectory and the actual / expected trajectory (perhaps based on the position on the path) is less than a threshold). For example, the WTRU may indicate information about the determined trajectories (e.g., ID / index) to the network, possibly together with confidence / weight / probability values ​​associated with different determined trajectories.

[0167] In an example, the WTRU may be configured with one or more tracks associated with one or more satellites. In this case, the WTRU may determine to perform PRS measurements at a lower frequency per track than when the WTRU may be configured with one track, for example.

[0168] The assistance data and / or configuration received by the WTRU may include a priority value. For example, the WTRU may receive and / or be configured with a priority value associated with positioning using a mobile access node or positioning using a stationary access node (e.g., geostationary satellite, fixed TRP). For example, such a priority value may indicate the type of positioning method that the WTRU may use.

[0169] In order to utilize mobile access nodes for positioning, the WTRU may receive and / or be configured with priority values ​​associated with one or more mobile access nodes. For example, such priority values ​​may indicate a preference for selecting / using mobile access nodes / satellites for positioning.

[0170] In an example, the WTRU may also receive a priority value for a PRS / SRSp configuration that indicates a PRS / SRSp configuration to be used when performing positioning with a mobile access node. For example, the WTRU may select a satellite and / or associated PRS / SRSp configuration based on a priority order, where when multiple satellites and / or configurations are available, the satellite and / or PRS / SRSp configuration with the highest priority is used first for positioning measurements, followed by the next highest priority.

[0171] In an example, a WTRU may receive a priority value indicating satellites for the WTRU to search for (e.g., prioritizing GEO over LEO, prioritizing quasi-geostationary over geostationary). Such a priority value may indicate satellites preferred by the network, which may be determined based on prior knowledge or system preferences. For example, such a priority value may be received by the WTRU based on an indication / information transmitted by the WTRU to the network. For example, when the WTRU indicates a preference for power saving (e.g., an indication that battery life / capacity is low or below a threshold), the WTRU may receive priority values ​​for some satellites (e.g., satellites with low altitudes that may not require a high RSRP at the WTRU during measurements), which may allow the WTRU to, for example, save battery or improve power saving when searching / selecting satellites for positioning.

[0172] The assistance data and / or configuration received by the WTRU may include an error threshold. For example, the WTRU may receive one or more error thresholds (e.g., ToA threshold, RSRP threshold, RSTD threshold, RTOA threshold, number of multipaths) and / or positioning QoS (e.g., accuracy, integrity, latency) associated with a measurement.

[0173] In an example, an error threshold may be associated with determining dilution of precision (DOP). For example, a DOP condition may be determined as follows: given the position of the WTRU, the difference / diversity in the positions of one or more mobile satellites used for positioning at different measurement time instances is less than a threshold. In this case, for example, when the calculated / detected DOP condition is above / below a DOP error threshold, the WTRU may determine a positioning error.

[0174] For example, when performing measurements of DL signals (e.g., PRS, SSB) received from a mobile access node at different time instances, the WTRU may use an error threshold to determine whether the positioning measurements are within an expected error bound / threshold and / or whether positioning QoS requirements are met.

[0175] The assistance data and / or configuration received by the WTRU may include correction information and / or compensation information. For example, the WTRU may receive correction / compensation information / parameters to be applied when performing measurements of DL signals (e.g., PRS) received from NTN nodes / satellites and / or mobile TRPs.

[0176] For example, in an example, the correction information may include one or more TA values ​​(e.g., a common TA value and / or a WTRU-specific / differential TA value). For example, the common TA value may be associated with a reference point on a cell / beam transmitted by an access node / satellite. In an example, the reference point may correspond to a location at the center of the cell / beam transmitted by the access node / satellite. For example, the WTRU may receive location information (e.g., coordinates) of one or more reference points associated with a cell / beam transmitted by an access node / satellite. For example, such common TA and / or location information of the reference points may be used to determine a differential TA and / or a relative WTRU position.

[0177] For example, in an example, the WTRU may receive a set of common TA values ​​associated with different reference points and / or different transmission time instances on a cell / beam (e.g., associated with a trajectory of a mobile access node / satellite). Such a set of common TA values ​​may be associated with a positioning configuration (e.g., an SRSp configuration). For example, in order to determine a TA value (e.g., a differential TA and / or a common TA) to use when performing an SRSp transmission at a transmission time instance, the WTRU may select an appropriate common TA value based on information received from the network (e.g., trajectory information, association information between the transmission time instance and the common TA value).

[0178] The WTRU may also receive correction / compensation information / parameters to be applied when performing transmission of UL signals (e.g., SRSp) to NTN nodes / satellites and / or mobile TRPs.

[0179] For example, when the measurements / estimations are invalid, the WTRU may use correction / compensation information / parameters to recover from the error condition.

[0180] In an example, the correction information may be related to a timing / phase error (e.g., associated with a satellite and / or PRS configuration / resource) indicating a difference between time instances / phases when a PRS is generated and sent by a gNB and / or satellite. For example, the correction information may be related to a timing / phase error (e.g., associated with a WTRU and / or SRSp configuration / resource) indicating a difference between time instances / phases when a WTRU generates and sends a SRSp.

[0181] In an example, the correction information received by the WTRU may be related to the timing / phase error expected at different positioning / coverage / reference areas and / or time instances. When performing measurements of PRS and / or transmission of SRSp, the WTRU may use the corresponding correction information based on PRS / SRSp resource, satellite / TRP / gNB, area, time instance.

[0182] In an example, the WTRU may receive correction information / thresholds associated with error sources at the gNB / TRP, mobile access node, and / or channel / link (e.g., Uu link, feeder / backhaul link between gNB and satellite, relay link between WTRU and satellite), including synchronization error, timing error (e.g., gNB / access node / satellite Tx TEG ID, Tx-RxTEG ID, Rx TEG ID), multipath, LOS / NLOS, and errors in satellite trajectory / ephemeris data. For example, the WTRU may use such correction information when operating in a WTRU-based mode and / or when the WTRU estimates the trajectory of a mobile access node based on measurements at different time instances.

[0183] The assistance data and / or configuration received by the WTRU may include a reporting configuration. For example, the WTRU may receive a reporting configuration to be applied when transmitting information about positioning measurements associated with a mobile access node. For example, the reporting configuration may include an ID / index to be used (e.g., LPP ID, satellite / NTN node ID, WTRU ID, positioning method ID). In an example, the reporting configuration may include whether to report absolute / average / minimum / maximum values ​​related to measurements made on a PRS (e.g., ToA, RSRP, RSTD measurements made on a resource / beam / cell associated with the PRS).

[0184] In an example, the reporting configuration may include a reporting periodicity (e.g., whether the reporting is to be aligned with the measurement / transmission), an offset relative to the start / end of the measurement, and events that the WTRU may monitor / detect to transmit a report to the network. For example, the WTRU may transmit a report on positioning measurements / estimates / uncertainties upon detecting a change in radio conditions (e.g., ToA and / or RSRP above / below a threshold), detecting a change in the mobility state of an access node / satellite, and / or detecting a change in the trajectory of a mobile access node (e.g., the access node deviates from a straight path).

[0185] For example, the WTRU may include timing information (e.g., timestamps) in the report to indicate when to start / stop measurements at different time instances. For example, when configured with a set of measurement time instances and / or when using the configured time instances to perform measurements of PRS received from a mobile access node, the WTRU may transmit a set ID in the report.

[0186] In an example, when the WTRU performs prediction, extrapolation, and / or interpolation during a time instance when no PRS measurements (e.g., ToA) from a mobile access node are made, the WTRU may transmit timing information (e.g., timestamp) related to a start time, duration, and / or stop time associated with the prediction. When performing extrapolation / interpolation of measurements, the WTRU may transmit information about the uncertainty of the prediction, confidence values, and / or weight values ​​associated with different instances of extrapolated / interpolated measurement values.

[0187] The assistance data received by the WTRU may be common across different positioning areas (e.g., including multiple cells / TRPs / gNBs / access nodes), or specific to one or more cells / TRPs / gNBs / satellites. For example, when the WTRU receives TRP / satellite-specific assistance data (e.g., associated with the ID of the TRP / satellite), the WTRU may use the associated assistance data when it is under the coverage of that TRP / satellite.

[0188] The WTRU may perform one or more measurements (e.g., such as RSRP and / or ToA) of a PRS received from a mobile satellite based on a time difference (e.g., RSTD) calculation relative to a reference point on a cell / beam associated with the satellite. The WTRU may be configured to receive configuration information from the network. The WTRU may perform a first RSRP and / or first TOA measurement of a PRS received from a satellite at a first measurement time instance. If the measured RSRP is greater than or equal to an RSRP threshold and the measured TOA minus the expected TOA at the reference point is less than an RSTD threshold, the WTRU may perform a second RSRP and / or TOA measurement of the PRS at a second measurement time instance, and perform a third RSRP and / or TOA measurement of the PRS at the second measurement time instance using an alternate PRS configuration. If the measured RSRP is less than the RSRP threshold, the WTRU may select an alternative satellite and / or perform a second RSRP and / or TOA measurement of the PRS at the second measurement time instance using the alternate PRS configuration. The WTRU may report the first RSRP, the second RSRP and / or the third RSRP to the LMF and / or report TOA measurements to the LMF.

[0189] In an example, when any of the DL-based positioning methods (e.g., DL-TDoA, DL-AoD) is used, the location information of the WTRU may be determined in a scenario where one or more of the access nodes are moving. The location of the WTRU may be determined based on signals (e.g., DL-PRS) sent by the mobile access nodes and / or measurements made by the WTRU.

[0190] In timing-based methods (e.g., DL-TDoA, OTDOA), the distance between the WTRU and one or more mobile access nodes may be estimated at different time instances for determining the location of the WTRU. The distance between the WTRU and one or more mobile access nodes may be estimated based on the time of arrival (ToA). For example, ToA may refer to any measurement or estimation performed by the WTRU to determine the reception or arrival time of a DL signal (e.g., PRS, SSB, PSS / SSS signals, initial access messages such as Msg B, Msg 2, Msg 4). Such ToA measurements may include determining SFN offset, receive time slot, TA indication / command, timestamp, Doppler shift / expansion, etc.

[0191] For example, when a timestamp is used in a DL signal to indicate ToA, the format (e.g., UTC time) and / or granularity (e.g., milliseconds) applied when indicating the time may allow determination of the distance traveled by the DL signal (e.g., from the access node to the WTRU) before being received at the WTRU.

[0192] In an example, the ToA may be determined as a relative ToA (RTOA) measurement relative to a reference ToA measurement. In this case, for example, the reference ToA may be measured on a PRS received from a reference node (e.g., a geostationary satellite) or a gNB / ground station.

[0193] In an example associated with NTN, the WTRU may measure the ToA of a PRS sent by a gNB / ground station and / or relayed by an NTN node / satellite. In this case, the ToA may be determined by the WTRU based on knowledge of the transmission time (e.g., via SFN / NR timeslots) or based on timestamp information carried explicitly or implicitly in the DL signal (e.g., PRS). This method for determining ToA may be applicable when the WTRU and gNB are time synchronized (e.g., synchronized with respect to a common clock). For example, the difference between the reception time and the transmission time may indicate the UL distance and / or DL ​​distance traveled by the DL signal.

[0194] The distance between the WTRU and one or more mobile access nodes may be estimated based on RSTD. For example, RSTD may refer to the difference between the ToA of any DL signal (e.g., PRS, SSB) sent by an access node (e.g., satellite, NTN node, mobile TRP) and the ToA of the DL signal sent by a reference node (e.g., gNB, PRU, geostationary satellite).

[0195] The distance between the WTRU and one or more mobile access nodes may be estimated based on RSRP. For example, RSRP may refer to a received power measurement of any DL signal (e.g., PRS, SSB, PSS / SSS signals, initial access message).

[0196] For example, the WTRU may perform any of the above-mentioned measurements of the PRS received from the mobile access node / satellite at one or more measurement time instances (e.g., configured via assistance data), periodically (e.g., using a configured periodicity value), and / or when triggered by an event (e.g., a measurement / estimation error is above a threshold).

[0197] In an angle-based method (e.g., DL-AoD), the distance and / or direction between the WTRU and one or more mobile access nodes may be estimated at different time instances based on measurements of RSRP, AoD, and / or AoA of one or more PRS beams transmitted by the access node / satellite. When using a mobile access node / satellite for positioning, the WTRU may use the same or different TX beams associated with the PRS transmitted by the access node / satellite at different measurement time instances. For example, such information about the PRS TX beams used by the mobile access node / satellite may be received by the WTRU as assistance data from the network. For example, the WTRU may use the corresponding RX beam based on the assistance data for performing measurements of the PRS TX beams. Alternatively, for example, when the assistance data is not available or partially available, the WTRU may perform a beam selection process (e.g., by performing a WTRU-based beam scan) to identify the TX beams used by the mobile access node / satellite at different measurement time instances. In an example, the WTRU may determine / select a TX beam based on knowledge of trajectory / ephemeris information associated with a mobile access node / satellite (eg, configured in the WTRU via assistance data).

[0198] In one solution, when using the WTRU-based positioning mode and / or the WTRU-assisted (eg, network-based) positioning mode, the WTRU may be configured for DL-based positioning with one or more access nodes that are movable.

[0199] In the WTRU-based positioning mode, the WTRU may perform measurements of the PRS received from the mobile access node and / or may calculate its position based on the measurements and the location information of the mobile access node at different time instances when the measurements are made. For example, the location information of the mobile access node may be configured / received by the WTRU as assistance data. For example, when calculating the WTRU position, the WTRU may apply corrections by taking into account any errors due to the location and / or relative movement of the WTRU with respect to the mobile access node.

[0200] In WTRU-assisted (network-based) positioning mode, the WTRU may perform measurements of PRS received from a mobile access node and transmit measurement reports to the network (e.g., LMF, gNB) for use in calculating the WTRU position. The measurement report may include information of the mobile access node / satellite used for positioning (e.g., satellite ID, track ID) and / or a timestamp indicating the time instance when the WTRU performed the PRS measurement. The timestamp included by the WTRU in the measurement report may be indicated as a relative time relative to a start / reference time. For example, the measurement and timestamp of PRS (e.g., ToA, RSRP) may indicate where the WTRU may start performing the measurement relative to the track of the mobile access node / satellite sending the PRS.

[0201] In an example, the WTRU may be configured to use one or more PRS configurations and / or PRS parameters (e.g., periodicity, bandwidth) based on mobility attributes of the access node and / or the WTRU. Such PRS configurations / parameters may be applicable to both WTRU-based and WTRU-assisted methods, and may be intended to ensure high quality PRS measurements and positioning accuracy when using mobile access nodes. For example, the mobility attributes associated with a mobile access node may include any of the altitude, the distance of the access node from the WTRU, the speed of the access node, and the direction of movement of the access node relative to the WTRU.

[0202] For example, when the speed of the access node is high (e.g., above the speed threshold described above), the WTRU may select / determine to use a first PRS configuration (e.g., a first PRS resource set) having high resource density, high periodicity, high repetition, and / or high bandwidth. Similarly, for example, when the speed of the access node is low (e.g., below the speed threshold), the WTRU may select / determine to use a second PRS configuration (e.g., a second PRS resource set) having relatively low density, low periodicity, and / or low bandwidth.

[0203] In an example, to enable the WTRU to select / determine an appropriate PRS configuration / parameter, the WTRU may be pre-configured with one or more PRS configuration / parameters, one or more thresholds associated with mobility attributes (e.g., speed, direction), and association information indicating an association between the mobility attributes and the PRS configuration / parameter. For example, such configuration information may be received by the WTRU from the network (e.g., LMF, gNB) as assistance data.

[0204] In this case, when the WTRU is configured to use one or more mobile access nodes, WTRU-based DL positioning, or WTRU-assisted DL positioning, the WTRU may determine the mobility attributes of the access node and select an appropriate PRS configuration based on the determined mobility attributes. For example, the mobility attributes of the access node may be determined by the WTRU based on indications / information received from the network (e.g., via assistance data including trajectory / ephemeris data) and / or directly from the mobile access node (e.g., via direct indications over a Uu link or SL that indicate a trajectory corresponding to the access node, current / expected speed, current / expected direction, etc.). In an example, the WTRU may determine the mobility attributes based on measurements of signals (e.g., an initial / default PRS or SL-PRS) that may be received from the mobile access node over one or more time instances / durations. For example, the WTRU may also estimate the trajectory of the mobile access node (e.g., an association between a location and a time instance) based on measurements of the received signals.

[0205] For example, when determining the mobility attribute, the WTRU may select one or more PRS configurations and / or PRS parameters based on pre-configured assistance data for performing measurements of the PRS received from the mobile access node. For example, the WTRU may transmit an indication (e.g., an on-demand indication) requesting configuration / activation of the selected PRS configuration / parameters to the mobile access node and / or the network (e.g., LMG, gNB). Alternatively, the WTRU may transmit measurements (e.g., RSRP, Doppler, or ToA measurements of signals received from the access node) and / or indications regarding mobility attributes (e.g., estimated speed, trajectory) to the access node and / or the network. The WTRU may receive a PRS configuration / parameter and / or an activation / deactivation indication triggering the use of the PRS configuration / parameter from the network or access node. For example, the WTRU may use the associated PRS configuration / parameters to perform measurements of the PRS received from the mobile access node.

[0206] In the WTRU-based case, the WTRU may determine its position based on PRS measurements performed using one or more PRS configurations / parameters and other assistance data or estimates (e.g., trajectory information of a mobile access node). For example, in the WTRU-assisted case, the WTRU may transmit a measurement report to the network, which may include information about the mobile access node used for positioning (e.g., ID), timing information of the measurement (e.g., timestamp), estimated trajectory information of the mobile access node, and any relative mobility / mobility attributes of the WTRU.

[0207] In an example, the WTRU may select one or more mobile access nodes (e.g., satellites, TRPs) for positioning based on configured selection criteria. For example, the selection criteria may be received by the WTRU from the network (e.g., as assistance data) and / or from any of the mobile and / or stationary access nodes.

[0208] In an example, corresponding to transparent mode, the WTRU may not be directly aware that one or more access nodes / TRPs indicated by the network for positioning are mobile. The WTRU may receive indication / assistance data (e.g., access node / satellite / TRPID) from the network, possibly together with PRS configuration and other assistance data, such as measurement time instance. Upon detecting a trigger associated with a mobile access node (e.g., detecting a configured ID in an SSB associated with the mobile access node), the WTRU may perform measurements of the PRS received from the mobile access node. Upon measuring a DL signal received from the mobile access node (e.g., the RSRP of the initial PRS or SSB is above a threshold), the WTRU may perform measurements of the PRS received from the mobile access node. Upon receiving an indication from the network (e.g., an LPP request for location information, an indication to configure / activate measurement gaps), the WTRU may perform measurements of the PRS received from the mobile access node.

[0209] For example, when reporting measurements to the network, the WTRU may report according to the reporting configuration provided in the assistance data, or the WTRU may include some indication (e.g., timing information / timestamp indicating when the measurement was made) that indicates that the WTRU may have detected that one or more of the access nodes may be mobile during the measurement.

[0210] In an example, the WTRU may be configured with selection criteria for selecting one or more mobile access nodes for positioning. The selection criteria may include one or more of the following.

[0211] The selection criteria may include trajectory and / or ephemeris data. For example, the WTRU may select a mobile access node / satellite when the mobile access node is observable / detectable by the WTRU and / or the trajectory data of the mobile access node is aligned with the time window used by the WTRU for positioning.

[0212] The selection criteria may include the accuracy and / or reliability of the location and / or trajectory information of the mobile access node. For example, when the accuracy of the location information and / or trajectory information of the mobile access node is above / below one or more configured thresholds, the WTRU may select the mobile access node. For example, when the accuracy of the location information of the mobile access node is less than a threshold, the WTRU may not select the access node for positioning.

[0213] The selection criteria may include the speed and / or direction of the mobile access node / satellite. For example, the WTRU may select a mobile access node when its speed is above / below one or more configured speed thresholds. For example, the WTRU may not select an access node that may be moving quickly. For example, the WTRU may select a mobile access node whose mobility direction is above / below one or more configured angle / direction thresholds (possibly relative to the direction of the WTRU).

[0214] The selection criteria may include the quality of the measurement. For example, when the measurement of the signal (e.g., initial / default PRS, SSB, PSS, SSS) received from the access node is above / below one or more configured thresholds, the WTRU may select the mobile access node. For example, the measurement performed by the WTRU may include any of ToA, AoA, RSTD, RSRP, etc. For example, other measurements that the WTRU may perform to decide whether to select the mobile access node include path loss, number of multipaths, LOS / NLOS identification, etc. For example, when the measurement of the signal indicates poor quality, the WTRU may not select the access node.

[0215] The selection criteria may include selection priorities and / or preferences. For example, the WTRU may select an access node / satellite for positioning based on a priority order indicated by the network. For example, the WTRU may select a mobile access node that can be detected by the WTRU with the highest priority and then with the next highest priority. In an example, a stationary access node (e.g., a fixed TRP, a geostationary satellite) may be indicated / assigned with a higher priority than a mobile access node. In this case, for example, when (e.g., only when) any stationary access node is not detectable / available (e.g., the WTRU cannot detect the ID of the stationary TRP in the SSB or cannot measure the PRS from the stationary TRP with an RSRP above a threshold), the WTRU may select a mobile access node for positioning.

[0216] The selection criteria may include the availability of assistance data associated with the access node. For example, the WTRU may select an access node / satellite when assistance data associated with the access node / satellite, including one or more PRS configurations, measurement time instances, separation criteria, etc., is available, pre-configured in the WTRU, and / or valid for use.

[0217] The selection criteria may include a time window and / or a delay for positioning. For example, the WTRU may select one or more mobile access nodes whose trajectories may overlap with the time window used by the WTRU for positioning. The time window for positioning may include a starting time instance / time slot, an ending time instance / time slot, and / or a maximum time duration / time delay, for example, during which the WTRU may perform measurements of PRS received from one or more mobile access nodes.

[0218] In an example, the WTRU may be configured to use a set of access nodes / TRPs for positioning, where the set may include a combination of different mobile access nodes / TRPs or a combination of mobile access nodes / TRPs and stationary access nodes / TRPs. Using and / or selecting such a set may allow the WTRU to use different types of access nodes / TRPs simultaneously or switch between different mobile access TRPs or between stationary TRPs and mobile TRPs. For example, the WTRU may switch between using different access node / TRP types based on detecting one or more events, including temporary blocking of the link between the WTRU and the TRP, poor coverage conditions at the WTRU (e.g., the RSRP of the PRS received by the WTRU from any of the TRPs is below a threshold), detection of a DOP condition, an increase / decrease in access node speed, a change in trajectory, etc.

[0219] For example, when some assistance data (e.g., latest location, trajectory information) or indication is received from a mobile TRP, the WTRU may combine the assistance data from different sources (e.g., LMF in an existing LPP session, pre-configured in the WTRU in a previous LPP session, directly from the mobile TRP) to determine the appropriate PRS configuration to use when performing measurements of PRS received from a combination of different types of TRPs.

[0220] In an example, when the WTRU is configured (e.g., via assistance data) with the option to select between a stationary access node / TRP and a mobile access node / TRP, the WTRU may initially select one or more fixed / stationary TRPs for performing DL-PRS measurements based on selection criteria (e.g., a stationary TRP may have a higher priority than a mobile TRP). For example, when triggered by an event (e.g., link blocking) based on the configured assistance data associated with the mobile TRP, the WTRU may then switch to selecting and / or using the mobile TRP. The assistance data and / or PRS configuration / parameters associated with the mobile TRP may be different from the assistance data and / or PRS configuration / parameters associated with the stationary TRP. For example, when switching between a stationary TRP and a mobile TRP, the WTRU may be instructed by the network (e.g., later signaled via LPP or AS) and / or select the appropriate assistance data and PRS configuration. For example, in WTRU assisted mode, the WTRU may report to the network timing information / timestamps indicating the time instances when switching between the stationary TRP and the mobile TRP together with the TRP ID and PRS measurements.

[0221] In an example, the WTRU may transmit positioning information, indications and / or reports (e.g., position measurements / estimations) to the network, for example, based on measurements performed on PRSs received from one or more mobile access nodes. In an example, the WTRU may transmit positioning information based on a reporting configuration received in the assistance data. For example, the WTRU may transmit positioning information / reports after the measurements are completed and / or upon detection of a triggering event / condition as described above (e.g., receiving a request from the network, periodic reporting, switching between different types of mobile access nodes or different configurations, detection of errors, etc.). For example, in an example related to UL-based positioning, the WTRU may transmit an indication to the network due to any of the following: when requesting an SRSp configuration and / or activating / deactivating a pre-configured SRSp configuration, and switching between different SRSp configurations.

[0222] Positioning information / reports may be transmitted by the WTRU periodically or based on event triggers in any of the following: LPP messages (e.g., LPP Provide Location Information messages), AS layer messages (e.g., RRC signaling, MAC CE, UCI, PUSCH data). Positioning information that may be transmitted by the WTRU when using a mobile access node for positioning may include one or more of the following.

[0223] The positioning information transmitted by the WTRU may include location information and / or measurements. For example, the WTRU may transmit a determined / estimated WTRU location (e.g., coordinates, relative position with respect to a reference point / location) and / or measurements used to determine / estimate the WTRU location. For example, the WTRU may transmit location information using absolute values ​​(e.g., normal coordinates) or truncated values ​​(e.g., abbreviated coordinates). For example, such information may be transmitted along with timing information (e.g., a timestamp indicating when the measurement / estimation was performed) and / or an ID / index of a configuration applied during the measurement, the configuration including a PRS configuration, a measurement time instance / window, and a separation criterion. The WTRU may send an indication of at least one of a mobile network node identity or WTRU location information to the network or satellite.

[0224] For example, when transmitting timing information (eg, timestamp), the WTRU may report an absolute time (eg, UTC) or a differential time (eg, a time difference relative to a previous / reference time instance / occasion).

[0225] In an example, the WTRU may transmit information about any other measurements and estimates, including measurements of GNSS signals (e.g., used to estimate the initial WTRU position), measurements of RRM signals (e.g., CSI-RS, SSB), and estimates of TA (e.g., WTRU or cell-specific TA), possibly in addition to PRS measurements. For example, such information may be used to improve the accuracy of the WTRU position.

[0226] The positioning information transmitted by the WTRU may include access node information. For example, the WTRU may transmit information (e.g., ID / index) about the access node / TRP / satellite used during positioning. For example, when using or switching to a mobile access node, the WTRU may also transmit timing information (e.g., timestamp) indicating the start / end time. In an example, the WTRU may transmit information about one or more PRS configurations / parameters (e.g., ID / index) used in association with the selection of a mobile access node. In an example, when using a reference unit for differential measurements (e.g., RSTD, differential timing / phase), the WTRU may transmit information (e.g., ID, timing information / timestamp) about any reference unit (such as a PRU, reference point, reference access node / TRP and / or reference satellite (geostationary satellite)).

[0227] The positioning information transmitted by the WTRU may include satellite related information. For example, when the WTRU is configured with a DL-TDoA or DL-AoD positioning method using one or more mobile satellites, the WTRU may report one or more of the following. The WTRU may report a satellite ID and / or a trajectory / ephemeris data ID. For example, the WTRU may report the reference time used (e.g., absolute time or relative time, where the time may be based on the GNSS synchronized time or SFN provided by the network) based on which the RSTD measurement / calculation is performed. For example, the WTRU may report the reference point used (e.g., the position on the cell / beam sent by the satellite and / or used by the WTRU) based on which position / TA estimates are made. The WTRU may report the PRS / SRSp configuration used (e.g., ID), including one or more cells / beams (e.g., cell / beam IDs), which may be associated with a satellite and / or a trajectory of a satellite. The WTRU may report ToA, RSRP and / or RSTD measurements made on the PRS and / or timing information (e.g., timestamp) indicating when the measurements were made.

[0228] The positioning information transmitted by the WTRU may include error information. For example, the WTRU may also indicate any errors due to time / phase / power measurements (e.g., timing / phase error group ID) and errors associated with the trajectory of the mobile access node (e.g., the difference between the expected trajectory / position and the estimated trajectory / position). In an example, the WTRU may report detection and / or measurement of error sources (e.g., multipath, NLOS, ionospheric error, tropospheric error).

[0229] The positioning information transmitted by the WTRU may include the achievable positioning QoS. For example, the WTRU may transmit information about the achievable positioning QoS (e.g., accuracy, integrity, latency, power saving), possibly relative to the requirements / KPIs received from the network (e.g., LMF, gNB). For example, the WTRU may report QoS information (e.g., accuracy, latency, integrity) on a per mobile access node / satellite basis.

[0230] The positioning information transmitted by the WTRU may include WTRU mobility and / or movement information. For example, the WTRU may transmit information about mobility state (e.g., stationary, moving at low / high speed), mobility / movement attributes (e.g., speed, direction, distance traveled in a straight / linear path), and / or trajectory information (e.g., a list of locations and / or a list of cells / TRP IDs detected by the WTRU over a duration of time).

[0231] The positioning information transmitted by the WTRU may include trajectory information of the mobile access node / TRP. For example, when estimating the trajectory of the mobile access node / TRP (e.g., based on PRS or SL-PRS measurements over a time duration), the WTRU may transmit trajectory information (e.g., trajectory ID, absolute or relative position of the access node relative to the WTRU at different time instances / timestamps), range information (e.g., distance / direction of the access node / TRP relative to the WTRU), and mobility attributes (e.g., speed and / or direction of the mobile access node).

[0232] The positioning information transmitted by the WTRU may include prediction and / or interpolation information. For example, the WTRU may transmit predicted / extrapolated location information / measurements (e.g., for time instances where measurements were not made or missed) and / or interpolated location information / measurements (e.g., estimates between two or more time instances). For example, the WTRU may transmit timing information (e.g., a timestamp) associated with the prediction / interpolation, which indicates the time instance / window when the WTRU applied the prediction / interpolation. In an example, the WTRU may also indicate a confidence level and / or uncertainty associated with the predicted / interpolated location information / measurements.

[0233] The WTRU may transmit positioning information (measurement reports / position estimates) to the network (e.g., LMF, gNB) and / or access nodes / satellites in one or more of LPP messages, AS layer signaling (e.g., RRC signaling / messages, UL MAC CE, or UCI), and / or initial access messages (e.g., RACH preamble, Msg A, Msg 1, Msg 3). For example, a WTRU with an LPP session may transmit positioning information to the network in NAS / LPP messages using SRBs (e.g., SRB1, SRB2, SRB3) or DRBs.

[0234] When operating in INACTIVE / IDLE mode, the WTRU may transmit positioning information / reports using a small data transmission (SDT) or early data transmission (EDT) configuration. The SDT / EDT configuration received by the WTRU from the network (e.g., serving gNB) may include information about validity conditions (e.g., TA timer) for maintaining the SDT / EDT, a maximum data size threshold for the payload of the message, periodicity, and / or resource grants (e.g., grants configured for SDT), etc.

[0235] For example, in order to minimize the amount of reporting and sending of positioning information, the WTRU may transmit differential positioning information (e.g., delta) relative to the information transmitted in the previous reporting instance. In an example, different types of positioning information (e.g., position information determined via measurement / estimation, error information) may be associated with different priority values, where the priority value may be received by the WTRU from the network as auxiliary data. In this case, the WTRU may apply different reporting periodicities or urgency levels to transmit positioning information based on the priority associated with the type of information to be reported. For example, the positioning information (which may include a change value greater than a threshold relative to previously reported information) may be transmitted at a higher periodicity or triggered at a higher urgency level (e.g., using an SR / BSR configuration associated with a high priority service). Similarly, for example, the WTRU may transmit information related to errors and / or changes relative to the expected trajectory of the mobile access node at a higher periodicity and / or a higher urgency level.

[0236] Figure 2 An example scenario 200 is depicted in which a WTRU 202 may perform one or more measurements (e.g., RSRP, ToA) of one or more PRS 204a, 204b, 204c received from a mobile satellite 206. The WTRU 202 may perform one or more measurements (e.g., RSRP, ToA) of one or more PRS 204a, 204b, 204c received from a mobile satellite 206 based on a time difference (e.g., RSTD) calculation relative to a reference point 208 on a cell / beam associated with the mobile satellite 206. Example processes applied by the WTRU 202 to perform DL-based positioning using the mobile satellite 206 may include one or more of the following. The WTRU 202 may receive configuration information from a network. The configuration information may include one or more PRS configurations, including at least a default / first PRS configuration and a second / alternative PRS configuration. For example, the second PRS configuration may include a PRS resource with a high repetition factor.

[0237] The configuration information may include a set of measurement time instances (e.g., a first time instance 212 and a second time instance 214) indicating when to measure the PRS received from the mobile satellite 206. The configuration information may include one or more reference points (e.g., such as the reference point 208) associated with each measurement time instance and an expected ToA value (e.g., a timestamp) for the PRS at the one or more reference points. The configuration information may include an RSRP threshold (e.g., used to determine the channel / link quality between the WTRU and the satellite). The configuration information may include an RSTD threshold 210. The RSTD threshold 210 may be used to determine the relative position of the WTRU 202 relative to the reference point 208 on the cell associated with the mobile satellite 206.

[0238] The WTRU 202 may perform a first set of RSRP and / or ToA measurements of a first PRS 204a received from the mobile satellite 206 at a first measurement time instance 212. The WTRU 202 may perform the first set of RSRP and / or ToA measurements using a first / default PRS configuration.

[0239] If the measured RSRP is greater than or equal to the RSRP threshold, and if the measured ToA - expected ToA at the reference point 208 is less than the RSTD threshold 210, the WTRU 202 may perform a second set of RSRP and / or ToA measurements of the second PRS 204c at a second measurement time instance 214 using the first / default PRS configuration. The WTRU 202 may transmit a measurement report to the network (e.g., LMF) including the first set and the second set of PRS measurements (e.g., RSRP and ToA measurements along with a timestamp indicating when the measurements were taken).

[0240] If the measured RSRP is greater than or equal to the RSRP threshold and if the measured ToA at the reference point 208, the expected ToA, is greater than or equal to the RSTD threshold 210, the WTRU 202 may perform a third set of RSRP and / or ToA measurements of the third PRS 204b using the second PRS configuration before the second measurement time instance 214. The WTRU 202 may perform a second set of RSRP and / or ToA measurements of the second PRS 204c using the second PRS configuration at the second measurement time instance 214. The WTRU 202 may transmit a measurement report to the network, the measurement report including the first set, the second set, and the third set of PRS measurements (e.g., RSRP and ToA measurements along with a timestamp indicating when the measurements were taken).

[0241] If the measured RSRP is less than the RSRP threshold, the WTRU 202 may perform a second set of RSRP and / or ToA measurements of a second PRS 204c at a second measurement time instance 214 using a second PRS configuration. Additionally or alternatively, the WTRU 202 may select an alternative satellite for PRS measurements, for example, based on the measured RSRP and / or the measured ToA. The WTRU 202 may report the first set and the second set of PRS measurements (e.g., RSRP and ToA, possibly with a timestamp indicating when the measurements were made) to the LMF.

[0242] Figure 2An example scenario 200 is depicted in which a WTRU 202 may perform one or more measurements (e.g., RSRP, ToA) of one or more PRS 204a, 204b, 204c received from a mobile satellite 206 at t1 212, t1', and / or t2 214 (e.g., as indicated by a measurement configuration (also referred to as a measurement separation configuration 216)) based on a time difference (e.g., RSTD) calculation relative to a reference point 208 on a cell / beam associated with the mobile satellite 206. The WTRU 202 may compare the time difference calculation to a configured RSTD threshold 210 to determine whether the WTRU 202 should perform additional measurements of the PRS received from the mobile satellite 206. The RSTD threshold 210 may be centered about the reference point 208. When the WTRU 202 has exceeded the RSTD threshold 210, the WTRU 202 may perform additional measurements of the PRS 204a, 204b, 204c. For example, the WTRU 202 may perform one or more measurements (e.g., RSRP, ToA) of the PRS 204a, 204b received from the mobile satellite 206 at t1212 and t1' (e.g., as indicated by the measurement configuration) based on a time difference (e.g., RSTD) calculation relative to a reference point 208 on a cell / beam associated with the mobile satellite 206.

[0243] Figure 3 An example scenario 300 is depicted for determining which measurement configuration to use to measure PRS received from a mobile access node. The WTRU 302 may determine measurement configurations 304, 306. The measurement configurations 304, 306 may include a set of time instances t0, t1, t2, t3, and / or t4 with different parameters (e.g., periodicity, duration) for measuring PRS 308a, 308b, 308c, 308d, 308e, 308f received from a mobile access node 310 (e.g., a drone) based on a relative distance 312a, 312b of the WTRU 302 relative to the mobile access node 310. Example processes applied by the WTRU 302 to determine the measurement configurations 304, 306 for use during DL-based positioning with the mobile access node 310 may include one or more of the following.

[0244] The WTRU 302 may receive configuration information from the network. The configuration information may include a first measurement configuration 304, a second measurement configuration 306 (e.g., an ID), a first distance threshold, and a second distance threshold. For example, the first measurement configuration 304 may include a set of time instances t0, t1, and / or t2 with high periodicity and a short measurement time duration / window. The first measurement configuration 304 may be used when the relative distance of the WTRU 302 relative to the access node 310 is low (e.g., the WTRU 302 is very close to / near the access node 310). For example, the second measurement configuration 306 may include a set of time instances t0, t2, and / or t4 with low periodicity and a long measurement time duration / window. The second measurement configuration 306 may be used when the relative distance of the WTRU 302 relative to the access node 310 is high (e.g., the WTRU 302 is far away from the access node 310). The first distance threshold and the second distance threshold may be used to compare the distance between the WTRU 302 and the mobile access node 310.

[0245] The WTRU 310 may perform a first set of measurements (e.g., RSRP, RSTD) of the first PRS 308a, the second PRS 308b, and the third PRS 308 received from the mobile access node 310 at a first time instance t0 using the first measurement configuration 304. The WTRU 302 may determine a distance 312a between the WTRU 302 and the mobile access node 310 based on the first measurement of the first PRS 308a. If the determined distance 312a is less than the first distance threshold, the WTRU 302 may perform a second measurement of the second PRS 308b (e.g., at a second time instance t1) using the first measurement configuration 304. If the determined distance 312a is greater than the first threshold but less than or equal to the second distance threshold, the WTRU 302 may select the second measurement configuration 306 and / or perform a second measurement of the fourth PRS 308d using the second measurement configuration 306. If the determined distance 312b is greater than a second threshold, the WTRU 302 may select an alternative access node to perform PRS measurements.

[0246] The WTRU 302 may send a measurement report to the network. The measurement report may include the first PRS measurement and the second PRS measurement (e.g., RSRP, RSTD, possibly with a timestamp indicating when the measurement was taken), information (e.g., ID) about the access nodes used for positioning (e.g., fixed and mobile), and / or information about the measurement configuration used by the WTRU 302 (e.g., ID and a timestamp indicating the time of selection / switching between different measurement configurations).

[0247] The WTRU 302 may determine whether to use a first measurement configuration 304 (e.g., high periodicity, short duration) or a second measurement configuration 306 (e.g., low periodicity, long duration) to measure a PRS 308 received from a mobile access node 310 (e.g., drone, satellite) based on the relative distance of the WTRU 302 relative to the access node.

[0248] Figure 4 An example scenario 400 is depicted of switching from using a first satellite 404 to using a second satellite 406. In an example, the WTRU 402 may switch between using different satellites 404, 406 to meet positioning QoS requirements (e.g., accuracy, latency) based on detecting a switching event 412 (e.g., low RSRP indicating poor link quality between the WTRU and the satellite). In this case, the switching between moving the satellites 404, 406 and / or reconfiguring the measurement configuration may be performed so that any additional latency and / or overhead due to the switching is minimized. Example processes applied by the WTRU 402 to switch between different satellites 404, 406 to meet positioning QoS may include one or more of the following.

[0249] The WTRU 402 may receive configuration information from the network. The configuration information may include ephemeris data (e.g., trajectory, velocity, position) associated with one or more satellites (e.g., such as satellite 404 and satellite 406), one or more PRS configurations associated with the one or more satellites, separation criteria (e.g., minimum spatial separation between two satellites or minimum spatial separation of a single satellite between two time instances 414a, 414b), positioning time window 416 (e.g., start time, maximum latency for PRS measurement, minimum number of measurement time instances), and / or RSRP thresholds (e.g., for detecting a handover event in which the WTRU 402 may handover to another satellite for positioning).

[0250] The WTRU 402 may select a first satellite 404 and may determine its associated measurement time instances 408a, 408b. For example, the measurement time instances 408a, 408b of the selected first satellite 404 may be determined based on ephemeris data, a separation criterion (e.g., such as a separation distance 414a of the first satellite 404), and / or a position fix time window 416. For example, the WTRU 402 may select a satellite (e.g., such as the first satellite 404) whose measurement time instances (e.g., the measurement time instances 408a, 408b) may overlap with the position fix time window 416 and whose time instances may occur earliest.

[0251] The WTRU 402 may perform measurements (e.g., RSRP) of the PRS received from the first satellite 404 at one or more measurement time instances 408a, 408b thereof after the position start time. The measurement time instances 408a, 408b may be separated by a separation distance 414a associated with the first satellite 404. If a handover event 412 is detected (e.g., the measured RSRP is below an RSRP threshold), the WTRU 402 may select a second satellite 406 and determine one or more measurement time instances 410a, 410b, 410c, 410d associated with the second satellite 406. For example, the measurement time instances 410a, 410b, 410c, 410d of the second satellite 406 may be determined based on ephemeris data, a separation criterion (e.g., such as a separation distance 414b of the second satellite 406), and / or a position fix time window 416. The WTRU 402 may perform measurements (eg, RSRP) of the PRS received from the second satellite 406 at one or more of its measurement time instances 410a, 410b, 410c, 410d after switching to the second satellite 406.

[0252] The WTRU 402 may send a measurement report to the network. The measurement report may include PRS measurements (e.g., RSRP, possibly with a timestamp) and / or satellite information (e.g., ID, possibly with a timestamp indicating a switching time from the first satellite 404 to the second satellite 406).

[0253] For example, the WTRU 402 may switch from using the first satellite 404 to using the second satellite 406 based on detecting the switching event 412 to meet one or more positioning QoS requirements (eg, such as accuracy, latency, etc.).

[0254] Figure 5 An example scenario 500 is depicted in which a measurement configuration is determined based on a relative movement of a WTRU 502 relative to a mobility threshold. In an example, the WTRU 502 may determine a measurement configuration 510, 512 to be used when performing measurements of a PRS 504, 506, 508 received from a mobile satellite 501, including a set of measurement time instances t1, t1', t2, based on the relative movement of the WTRU 502. Example procedures applied by the WTRU 502 to determine the measurement configuration taking into account the relative WTRU movement may include one or more of the following.

[0255] The WTRU 502 may receive configuration information (e.g., information) from the network. The configuration information may include a first measurement configuration 510, a second measurement configuration 512 (e.g., an ID), and / or a mobility threshold 505 (e.g., used to determine the amount of change in RSRP and / or ToA measurements at different time instances). For example, the first measurement configuration 510 may include a set of time instances t1" with high periodicity. The first measurement configuration 510 may be used when the relative mobility of the WTRU 502 is low (e.g., determined relative to the change in ToA and RSRP measurements of the PRS at different time instances). For example, the second measurement configuration 512 may include a set of time instances t1, t2 with low periodicity. For example, the second measurement configuration 512 may be used when the relative mobility of the WTRU 502 is high.

[0256] The WTRU 502 may perform a set of first and second measurements (e.g., RSRP, ToA) of the PRS 504, 508 received from the satellite 501 using the second measurement configuration 512. If the difference between the first and second measurements is less than the mobility threshold 505, the WTRU 502 may perform a third measurement of the PRS (e.g., RSRP, ToA) at the next time instance t1′ using the first measurement configuration 510. If the difference between the first and second measurements is greater than or equal to the mobility threshold 505, the WTRU 502 may perform a third measurement of the PRS (e.g., RSRP, ToA) at the next time instance t2 using the second measurement configuration 512.

[0257] The WTRU 502 may send a measurement report to the network. The measurement report may include the first PRS measurement, the second PRS measurement, the third PRS measurement, information (e.g., ID) about the access nodes (e.g., fixed and mobile) used for positioning, and / or one or more measurement configurations 510, 512 used by the WTRU 505 (e.g., ID and timestamp indicating the time of selection / switching between different measurement configurations). The first PRS measurement, the second PRS measurement, and the third PRS measurement may include RSRP, ToA, and / or a timestamp indicating when the measurement was taken.

[0258] The WTRU 502 may determine a measurement configuration 510, 512 (e.g., a set of measurement time instances within a time duration) to perform measurements of one or more PRS 504, 506, 508 (e.g., received from the mobile satellite 501 based on the relative movement of the WTRU 502 relative to a mobility threshold 505). When the movement of the WTRU 502 (e.g., determined based on an amount of change in PRS measurements) is below the mobility threshold 505, the WTRU 502 may switch from using the high periodicity measurement configuration 510 to the low periodicity measurement configuration 512.

[0259] In an example, when any of the UL-based positioning methods (e.g., UL-TDoA, UL-AoA) is used, the location information of the WTRU may be determined in a scenario where one or more of the access nodes are moving. The location of the WTRU may be determined based on UL signals (e.g., SRSp) transmitted by the WTRU and / or measurements made by network nodes / entities at one or more access nodes and / or satellites (e.g., mobile and stationary) and / or ground / terrestrial based base stations gNB, TRP, relay nodes, and PRUs. Since the location of the WTRU may be determined based on measurements of UL signals made at the network, any security issues that may be caused by potential exposure of the WTRU location to eavesdropping entities during initial access or during transmission of the WTRU location information may be mitigated.

[0260] As used herein, an "UL signal" may include one or more SRS or SRSp (SRS for positioning) transmissions that may be performed by a WTRU using any of SRS / SRSp resources, resource sets, beams, frequency layers, and configurations. As used herein, an "UL signal" may include one or more RACH preambles, sequences, partitions, and resources that may be sent by a WTRU during any of the RACH opportunities.

[0261] In order to send UL signals (e.g., SRSp, RACH preamble) for positioning, the WTRU may use resources and / or configurations that may be received from the network (e.g., gNB, LMF) and / or access node / TRP / satellite. For example, to ensure that the access node can accurately and reliably perform measurements of the UL signals and subsequently determine the location of the WTRU (e.g., at the gNB, at the LMF), the WTRU may apply certain adjustments / corrections to the UL signals based on the estimated / indicated TA value (e.g., differential TA, WTRU-specific TA). For example, in the case where the initial access message / signal is used for UL-based positioning, the WTRU may explicitly or implicitly initiate measurements at the TRP by sending an initial access message. The measurement report including measurements made by the access node / satellite / TRP may be forwarded to an anchor base station, gNB, BBU, or CU in the RAN, or forwarded to an AMF or LMF to determine the WTRU location.

[0262] When the WTRU is configured with a timing-based method for UL-based positioning (e.g., UL-TDoA), ToA, RTOA, RSTD and / or RSRP measurements made by a mobile access node / satellite at different time instances may be used to estimate the distance between the WTRU and the access node / satellite. For example, the estimated distance between the WTRU and the mobile access node at different time instances may be used to calculate the WTRU position.

[0263] When the WTRU is configured with an angle-based method for UL-based positioning (e.g., UL-AoD), the RSRP of the Tx beams transmitted by the WTRU at different time instances corresponding to the trajectory of the mobile access node is used to estimate the distance between the WTRU and the access node. For example, the WTRU may use the same / fixed or different Tx beams based on the knowledge of the trajectory / orientation of the access node / satellite.

[0264] Determining the WTRU location using UL-based positioning during initial access may include one or more of the following: For example, the WTRU location may be determined using transmission and / or measurement of SRSp / SRS and / or transmission and / or measurement of RACH signals or initial access messages.

[0265] For example, the WTRU may send SRSp or SRS at one or more time instances that may be received and measured by one or more access nodes. For example, the time instances for SRSp transmission may be preconfigured in the WTRU and / or determined by the WTRU based on trajectory / ephemeris information of the mobile access node / satellite and separation criteria.

[0266] For example, when performing transmission of SRSp, the WTRU may perform certain adjustments / corrections / offsets on the SRSp resources / signals based on the estimated TA value (eg, differential TA + common TA).

[0267] For example, the location of the WTRU may be determined (eg, at the network) based on any of RTOA, RSRP, RSTD, and AoA measurements made by one or more access nodes.

[0268] In an example, a WTRU may send a RACH preamble that may be received and measured by one or more access nodes. The measurements of the RACH preamble by the access nodes may include RTOA, RSRP, RSTD, AoA, AoD, correlation with known preambles / sequences, etc.

[0269] In an example, the WTRU may send a RACH preamble at a RACH opportunity dedicated to requesting msg2 which may include positioning related configuration (e.g., SRSp configuration). For example, the RACH opportunity dedicated to positioning or for requesting msg2 (including positioning configuration) may be broadcast by the network (e.g., in SIB / SSB) or pre-configured in the WTRU in RRC_CONNECTED and / or via an RRC_Release message.

[0270] In an example, the WTRU may send a RACH preamble or other initial access message in a subsequent UL transmission intended for positioning (e.g., during or after initial access). For example, the WTRU may perform a first transmission of a RACH preamble for initial access and / or for initiating positioning (e.g., in Msg1, MsgA) and a second transmission of a RACH preamble for UL-based positioning (e.g., in Msg 2 or beyond). For example, when performing the first transmission and / or the second transmission of the RACH preamble, the WTRU may perform certain adjustments / corrections / offsets on the RACH preamble based on an estimated TA value (e.g., differential TA+common TA).

[0271] To perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include one or more SRSp resources / configurations / parameters. For example, the SRSp resources / configurations may be associated with a mobile access node / satellite, or with a trajectory followed by an access node.

[0272] In order to perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include access node / satellite information, including ID, trajectory information, mobility attributes (e.g., speed, direction) and / or separation criteria. In order to perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include measurement / transmission time instances for sending SRSp. In order to perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include TA information (including common / cell / beam-specific TA) and / or assistance data for estimating differential / WTRU-specific TA. In order to perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include reference points associated with common / cell / beam-specific TAs, including location information (e.g., coordinates) of the reference points. In order to perform UL-based positioning using a mobile access node, the information / indication received by the WTRU may include parameters / thresholds associated with positioning (e.g., distance from the reference point).

[0273] Similarly, the message / indication sent by the WTRU to support UL-based positioning may include a request for configuration or activation / deactivation of one or more pre-configured SRSp resources / configurations / parameters and / or a request for assistance data associated with the access node / satellite (e.g., trajectory information, mobility attributes, transmission time instances, separation criteria).

[0274] The WTRU may send and / or receive any of indications, signaling (eg, control and data), messages, and configurations (eg, SRSp resources / configurations) in broadcast signaling, RRC signaling, LPP signaling, MAC CE, and / or L1 channels / signaling.

[0275] For example, the WTRU may access / acquire information used to perform positioning during and / or after initial access via any of the SIB, posSIB and / or SSB.

[0276] For example, the WTRU may send / receive any of a request message, a response message, and a configuration associated with positioning and / or initial access via an RRC message.

[0277] For example, the WTRU may send / receive any LPP message by using any of the identifiers associated with the LPP (eg, LPP session ID, LMF ID, WTRU ID, access node / satellite ID).

[0278] For example, the WTRU may send / receive any of a request message, a response message, a configuration, an activation / deactivation indication associated with positioning in one or more MAC CEs. For example, in the UL, a MAC CE that may carry any of a request or response message may be multiplexed in the PUSCH (e.g., when sending Msg 2, Msg A). Similarly, for example, in the DL, a MAC CE may be multiplexed in the PDSCH (e.g., when receiving Msg 4, Msg B).

[0279] L1 channels / signaling may include UCI (eg, PUCCH) or DCI (eg, PDCCH).

[0280] In an example, the WTRU may receive the SRSp configuration to be used from the network (e.g., LMF) or a fixed / stationary access node (e.g., gNB, TRP). In this case, the fixed access node may operate as an anchor access node (e.g., RRC / LPP / NRPPa anchoring) that may coordinate the WTRU (e.g., for triggering SRSp transmission) and / or the mobile access node (e.g., for measuring SRSp). In an example where the anchor access node is mobile, the WTRU may receive any of the new or updated SRSp configurations from the mobile access node.

[0281] The SRSp configuration received by the WTRU may indicate an association between a mobile access node and the SRSp. For example, the SRSp configuration may include an ID of a mobile access node for which it is desired to measure SRSps sent by the WTRU at different configured time instances associated with the SRSp configuration. For example, the WTRU may use the SRSp configuration based on detecting a mobile access node (e.g., an ID) so that SRSps sent by the WTRU at different time instances may be measured by the mobile access node.

[0282] Similarly, for example, the SRSp configuration may indicate an association between the SRSp and a trajectory that one or more access nodes are expected to follow. In this case, for example, the WTRU may use a pre-configured SRSp configuration based on detecting / estimating the trajectory (e.g., ID) of one or more access nodes so that the SRSp sent by the WTRU can be measured by any of the mobile access nodes following the trajectory.

[0283] In an example, the WTRU may receive an activation / deactivation indication indicating the transmission of one or more types of pre-configured SRSp (e.g., periodic SRSp, aperiodic SRSp, semi-persistent SRSp). For example, such an indication may be received by the WTRU from a network (e.g., LMF), a fixed / stationary access node (e.g., gNB, TRP), or from a mobile access node / satellite. For example, such an indication may be received via RRC signaling, MAC CE, or DCI. In an example, the WTRU may autonomously determine the activation / deactivation of SRSp transmission based on pre-configured assistance data (e.g., transmission time instances, trajectory information, separation criteria) and / or detection of one or more events (e.g., measurement events, estimation events, mobility events).

[0284] The WTRU may use the mobile access node to determine the SRSp parameters for UL based positioning.

[0285] In an example, a WTRU may be configured with one or more UL-based positioning methods (e.g., UL-TDoA, UL-AoD) based on sending UL signals (SRSp) to one or more mobile access nodes. In order to determine when to perform SRSp transmissions to mobile access nodes, the WTRU may be configured with a separation criterion (described in another section of the present disclosure) and / or a set of transmission time instances. For example, the separation criterion may indicate a minimum distance or spatial separation (e.g., following trajectory, speed, and direction) of mobile access nodes between at least two time instances used by the WTRU to perform SRSp transmissions. For example, the SRSp transmission time instance may correspond to a separation criterion associated with a mobile access node / satellite selected for positioning and / or performing SRSp measurements.

[0286] In an example, the WTRU may be instructed / configured to use one or more of the mobile access nodes (e.g., IDs) for UL-based positioning. Such configuration may be received by the WTRU via LPP or AS layer signaling (e.g., RRC messages) along with the SRSp configuration and other auxiliary data (e.g., trajectory information, transmission time instances, TA values). In an example, the WTRU may determine / select to use one or more mobile access nodes for UL-based positioning. The WTRU may transmit an indication to the network and / or the selected access node requesting configuration information (e.g., SRSp configuration, trajectory information) for positioning. For example, the WTRU may then perform SRSp transmissions at different time instances based on the configuration information received from the network / access node.

[0287] For example, in an example, the WTRU may determine the transmission time instance based on the received configuration information and / or other events detectable at the WTRU. For example, such events may include measurement events (e.g., the RSRP of a DL signal (such as an SSB or PRS) is below a threshold, which RSRP may be associated with or spatially correlated to the UL SRSp), estimation events (e.g., the estimated differential TA is above a TA threshold), or mobility events (e.g., a change in a mobility attribute, such as the speed or direction of the access node or the WTRU). In this case, for example, the WTRU may determine the transmission time instance based on a separation criterion, possibly by separating the SRSp transmissions with a periodic value that is aligned with the separation criterion or the trajectory of the access node.

[0288] In an example, the WTRU may determine the repetition factor to use when sending an SRSp based on the detection of any events. For example, when a measurement or estimation event is detected, the WTRU may increase the repetition factor when sending an SRSp, possibly in one or more transmission time instances. For example, when any of the events is no longer detectable or active, the WTRU may then fall back to using a default repetition factor.

[0289] In an example, the WTRU may update other parameters associated with the SRSp, including the transmit time instance, the number of resources / resource sets, the periodicity, the repetition factor, the Tx power, and the TA value, based on the mobility attributes of the access node / satellite, the change of trajectory, and the change of radio link conditions. For example, when selecting an access node / satellite whose distance or altitude to the WTRU is greater than a threshold, the WTRU may use a higher Tx power than the default Tx power value. Similarly, for example, when using a slowly moving satellite, the WTRU may increase the periodicity associated with the transmit time instance, or may increase the repetition factor while maintaining the periodicity. For example, the parameters that may be allowed to be updated by the WTRU may be pre-configured in the WTRU or determined by the WTRU based on the detection of any event. For example, when updating the SRSp parameters, the WTRU may transmit an explicit or implicit indication to the associated access node / satellite and / or the network.

[0290] In an example, in association with UL-RTOA measurements when performing an SRSp transmission to a mobile access node, the WTRU may be configured with a synchronization source (e.g., GNSS satellite, geostationary satellite, gNB) from which the WTRU may determine an absolute time. In this case, the first SRSp transmission performed by the WTRU to the mobile access node at the absolute time value may be used as a reference time, possibly for determining / calibrating the transmission time instance / window. For example, subsequent time instances at which the WTRU performs SRSp repetitions or new SRSp transmissions to the same mobile access node may be used to determine RTOA measurements relative to the first SRSp transmission.

[0291] Figure 6 An example scenario 600 is depicted for selecting an SRSp configuration for UL-based positioning with a mobile satellite 614. In an example, the WTRU 602, 604 may select an SRSp configuration (e.g., SRSp resource transmit power, periodicity, repetition factor) for UL-based positioning with a mobile satellite 614 based on determining a differential TA (e.g., a difference between a TA at the WTRU 602, 604 and a TA at a reference point 612) and a relative position of the WTRU 602, 604 with respect to the mobile satellite 614. Example processes applied by the WTRU 602, 604 to perform UL-based positioning with a mobile satellite 614 may include one or more of the following.

[0292] The WTRU 602, 604 may receive configuration information from the network (e.g., gNB, LMF). The configuration information may include a first SRSp configuration (e.g., including resources with a low repetition factor) and a second SRSp configuration (e.g., including resources with a high repetition factor). For example, when the WTRU 602, 604 may be located near a reference point 612 on a cell associated with a mobile satellite 614 (e.g., within a predefined location threshold) or when experiencing better link conditions (e.g., a link between the WTRU 602, 604 and the satellite 614), the first SRSp configuration may be used. For example, when the WTRU 602, 604 may be far away from the reference point 612 on the cell (e.g., beyond a predefined location threshold) or when experiencing poor radio link conditions, the second SRSp configuration may be used.

[0293] The configuration information may include a set of transmission time instances t1 , t2 associated with the first SRSp configuration and / or the second SRSp configuration.

[0294] The configuration information may include assistance data for calculating differential TA (e.g., including a set of common / cell-specific TA values ​​associated with different transmission time instances). The configuration information may include a differential TA threshold 610 for positioning. The differential TA threshold 610 may be used to determine whether the WTRU 602, 604 is located near the center of the reference point 612 or far away from the reference point 612.

[0295] The WTRU 602, 604 may determine a differential TA based on the received assistance data (e.g., a common TA). In an example, the WTRU 602, 604 may determine the differential TA based on initial positioning information (e.g., determined via GNSS) of the WTRU 602, 604. If the determined differential TA is less than a differential TA threshold 610, the WTRU 602, 604 may select a first SRSp configuration (e.g., a low repetition factor). If the determined differential TA is greater than or equal to the differential TA threshold 610, the WTRU 602, 604 may select a second SRSp configuration (e.g., a high repetition factor).

[0296] For example, the WTRU 602, 604 may transmit an indication to the network (e.g., gNB) or satellite requesting activation of the selected SRSp configuration. The WTRU 602, 604 may transmit the SRSp 606a, 606b, 608a, 608b while applying a total TA offset / compensation value (e.g., the total TA is a function of the differential TA and the common TA) to the SRSp 606a, 606b, 608a, 608b at the associated transmission time instance t1, t2. For example, upon receiving an activation indication from the network or satellite 614, the WTRU may transmit the SRSp 606a, 606b, 608a, 608b.

[0297] For example, the WTRUs 602, 604 may repeat the above sequence to perform UL-based positioning using the mobile satellite 614 at the next SRSp transmission time instance.

[0298] The WTRUs 602, 604 may select the first SRSp configuration or the second SRSp configuration to utilize the mobile satellite 614 for UL-based positioning based on determining the differential TA (e.g., relative to the TA associated with the reference point 612) and / or the relative position of the WTRUs 602, 604 relative to the mobile satellite 614. When the first WTRU 602 (e.g., WTRU1) is within the region indicated by the differential TA threshold 610, the first WTRU 602 may transmit the first SRSp 606a, 606b to the mobile satellite 614 using the first SRSp configuration at respective transmission time instances of t1 and t2. When the second WTRU 604 (e.g., WTRU2) is outside the region indicated by the differential TA threshold 610, the second WTRU 604 may transmit the second SRSp 608a, 608b to the mobile satellite 614 using the second SRSp configuration at respective transmission time instances of t1 and t2.

[0299] Figure 7 An example scenario 700 of RTT measurement configuration selection is depicted. In an example, a WTRU 702 may select a round trip time (RTT) measurement configuration 712, 714 for measuring a PRS 708 and transmitting SRSp 710a, 710b from / to a mobile satellite 704 based on determining a radio link quality between the WTRU 702 and a satellite 704. For RTT-based positioning, using the same Rx-Tx configuration (e.g., timing for PRS reception and SRSp transmission) may result in low positioning accuracy regardless of the relative WTRU position with respect to the mobile satellite 704. Example processes that may be applied by the WTRU 702 to select an appropriate RTT measurement configuration 712, 714 based on determining a link quality between the WTRU 702 and a mobile satellite 714 may include one or more of the following.

[0300] The WTRU 702 may receive configuration information from the network 706 (e.g., a gNB and / or LMF). The configuration information may include a multi-RTT configuration (e.g., including one or more PRS configurations and SRSp configurations), a first RTT measurement configuration 712 (e.g., including a long separation duration between PRS measurement and SRSp transmission), a second RTT measurement configuration 714 (e.g., including a short separation duration between PRS measurement and SRSp transmission), and / or an RSRP threshold. The RTT measurement configurations 712, 714 may be indicated by an ID and / or may include a set of time instances indicating time slots / opportunities for PRS reception / measurement and SRSp transmission. For example, when the link quality between the WTRU 702 and the satellite 704 is good (e.g., high RSRP), the WTRU 702 may use the first RTT measurement configuration 712, and when the link quality between the WTRU 702 and the satellite 704 is poor, the WTRU 702 may use the second RTT measurement configuration 714. The RSRP threshold may be used to determine the quality of the link between the WTRU 702 and the satellite 704.

[0301] The WTRU 702 may initially select a first RTT measurement configuration 712 and / or may perform a measurement (e.g., RSRP) of a PRS 708 received from a satellite 704 at a first time instance 716 associated with the first RTT measurement configuration 712. For example, such a measurement of a PRS 708 or any other DL signal (e.g., SSB) received from a satellite 704 may be performed by the WTRU 702 for determining a radio link quality (e.g., RSRP) between the WTRU 702 and the satellite 704.

[0302] If the measured RSRP is less than the RSRP threshold, the WTRU 702 may send the SRSp 710b using the resources in the SRSp configuration at the next time instance 718 associated with the first RTT measurement configuration 712. For example, if the PRS measurement indicates good link quality (e.g., link quality is greater than a predetermined threshold), the WTRU 702 may send the SRSp 710b using a longer / default separation duration after the PRS measurement.

[0303] If the measured RSRP is greater than or equal to the RSRP threshold, the WTRU 702 may select a second RTT measurement configuration 714. The WTRU 702 may send the SRSp 710a using the resources in the SRSp configuration at the next time instance 716 associated with the second RTT measurement configuration 714. For example, if the PRS measurement indicates poor link quality (e.g., link quality is below a predetermined threshold), the WTRU 702 may send the SRSp 710a using a shorter separation duration (e.g., fast SRS transmission) after the PRS measurement.

[0304] The WTRU 702 may measure the Rx-Tx time difference based on the selected RTT measurement configuration 712, 714 used and the separation time duration between the PRS measurement and the SRSp transmission.

[0305] The WTRU 702 may send a measurement report 720 to the network 706 (e.g., LMF). The measurement report 720 may include one or more PRS measurements (e.g., RSRP, possibly with a timestamp indicating when the measurement was made), one or more WTRU Rx-Tx measurements, information about access nodes (e.g., fixed and mobile) used for positioning (e.g., IDs), and / or RTT measurement configuration information (e.g., IDs and timestamps indicating the time to select / switch between different pre-configured RTT configurations).

[0306] The WTRU 702 may select an RTT measurement configuration to use (e.g., corresponding to WTRU Rx-Tx(1) 712 or WTRU Rx-Tx(2) 714) for measuring the PRS 708 and sending SRSp 710a, 710b to / from the mobile satellite 704 based on determining the quality of the radio link between the WTRU 702 and the satellite 704 (e.g., RSRP measurement). The base station 706 may transmit its own PRS signal to the mobile satellite 704. And the mobile satellite 704 may transmit the SRSp signal 710a, 710b to the base station 706. The base station 706 may transmit the PRS 708 to the mobile satellite 704 or transmit another signal 722 (e.g., different from the PRS) that may trigger the sending of the PRS 708 from the mobile satellite 704 to the WTRU 702. The mobile satellite 704 may transmit the SRSp signal 710a, 710b received from the WTRU 702 to the base station 706, or may send one or more other signals 724a, 724b (other than the SRSp) to the base station 706 upon receiving the SRSp 710a, 710b from the WTRU 702. The WTRU 702 may receive configuration information indicating a plurality of association sets from the mobile satellite 704. Each association set may include a plurality of corresponding time instances and a plurality of corresponding timing advance (TA) offsets. The WTRU 702 may send an indication of at least one of a mobile network node identity or WTRU location information to the satellite 704. The WTRU 702 may receive an indication of a first association set of the plurality of association sets from the satellite 704. The first association set may include one or more sets of WTRU TA offsets and / or satellite TA offsets. The WTRU 702 may begin sending a first sounding reference signal (SRSp) transmission 710a for positioning to the satellite 704 at a first time 716. The first time 716 may be determined based on at least a first TA offset of the first association set and a first time instance associated with the first TA offset.

[0307] The WTRU 702 may send a first SRSp transmission 710a to a satellite 704 corresponding to a mobile network node identifier or WTRU location information. The first time 716 may be a first TA value prior to the first time instance. The first TA value may be determined based on the first TA offset. The first TA value may be determined based on the sum of the first TA offset and the first WTRU TA offset. The first WTRU TA offset may be determined (by the WTRU, the satellite and / or the base station) based on the first location of the WTRU (e.g., or based on the first location relative to the satellite 704). The first TA offset may be selected from a first association set based on a resource associated with the first time instance for the first SRSp transmission 710a. The first TA offset may be selected based on an area in which the WTRU 702 and / or the satellite 704 are located. The configuration information may include an SRSp resource set. The first SRSp transmission 710a may be sent using at least one resource in the SRSp resource set.

[0308] The WTRU 702 may receive an indication of a second association set in a plurality of association sets. The WTRU 702 may begin transmitting a second sounding reference signal for positioning (SRSp) transmission 710b at a second time 718. The second time 718 may be determined based on at least a second TA offset for the second association set and a second time instance associated with the second TA offset. The second time 718 may precede the second time instance by a second TA value. The second TA value may be determined based on the second TA offset. The second TA value may be determined based on a sum of the second TA offset and a second WTRU TA offset. The second WTRU TA offset may be determined based on a second location of the WTRU 702 or a first location of the WTRU 702.

[0309] Figure 8 Another example selection 800 of a sounding reference signal (SRS) (SRSp) configuration for positioning for uplink-based positioning using a mobile satellite 826 is depicted. The WTRU 802 may be located in any of the following reference zones: reference zone 1 804, reference zone 2 806, reference zone 3 808, reference zone 4 810, and reference zone 5 812. Figure 8As shown, the WTRU 802 may be located in reference zone 2 806. The WTRU 802 may receive configuration information indicating a plurality of association sets from a satellite 826. Each association set may include a plurality of corresponding time instances and a plurality of corresponding timing advance (TA) offsets. The WTRU 802 may send an indication of at least one of a mobile network node identity or WTRU location information to the satellite 826. The WTRU 802 may receive an indication of a first association set of the plurality of association sets from the satellite 826. The WTRU 702 may begin sending a first sounding reference signal (SRSp) 814 for positioning to the satellite 826 at a first time (e.g., t0 820). The first time (e.g., t0 820) may be determined based on at least a first TA offset of the first association set and a first time instance associated with the first TA offset.

[0310] The TA offset may be any number (e.g., 0, positive and / or negative). The TA offset may be determined based on the location of the satellite relative to the location of the WTRU. As the satellite moves closer to the WTRU, the TA offset may decrease. As the satellite moves away from the WTRU, the TA offset may increase. In some examples, the TA offset may decrease and then increase (e.g., 0 ms [starting TA offset where the satellite is to the left of the WTRU], -1 ms [satellite moves to the right closer to the WTRU], -2 ms, -3 ms [satellite is directly above / closest to the WTRU], -2 ms [satellite moves to the right away from the WTRU], -1 ms, 0 ms [satellite is on the opposite side of the WTRU starting point], 1 ms, 2 ms, 3 ms, 4 ms, etc.). The TA offset may increase only in some examples (e.g., 0 ms [starting TA offset], 1 ms [satellite moves away from the WTRU], 2 ms, 3 ms, 4 ms, etc.).

[0311] The WTRU 802 may receive an indication of a second association set in a plurality of association sets. The WTRU 802 may begin sending a second sounding reference signal (SRSp) 816 for positioning to a satellite 826 at a second time (e.g., t1 822). The second time 822 may be determined based on at least a second TA offset of the second association set and a second time instance associated with the second TA offset. The second time 822 may precede the second time instance by a second TA value. The second TA value may be determined based on the second TA offset. The second TA value may be determined based on a sum of the second TA offset and a second WTRU TA offset. The second WTRU TA offset may be determined based on a second position of the WTRU (e.g., reference zone 1 804, reference zone 3 808, reference zone 4 810, and / or reference zone 5 812) or a first position of the WTRU (e.g., reference zone 2 806). The WTRU 802 may send a third SRSp 818 to the satellite 824 at a third time 824.

[0312] Fig. 9 Depicted is a process 900 for sending an uplink SRSp with a timing advance (TA).

[0313] At 902, a WTRU (e.g., such as WTRUs 102a, 102b, 102c, 102d shown in FIG. 1a, WTRU 102 shown in FIG. 1b, WTRU 102a, 102b, 102c shown in FIG. 1c, WTRU 102a, 102b, 102c shown in FIG. 1d, Figure 2 The WTRU 202 shown, Figure 3 The WTRU 302 shown, Figure 4 The WTRU 402 shown, Figure 5 The WTRU 502 shown, Figure 6 The WTRUs 602, 604, Figure 7 The WTRU 702 and / or Figure 8 The WTRU 802 shown may receive configuration information (e.g., from an LMF and / or a satellite). The configuration information may include at least one SRSp configuration (e.g., a set of SRSp resource sets), a SRSp Tx time configuration (e.g., a set of transmit time instance values ​​or transmit timings (absolute time, based on subframe number (SFN), symbol / slot / SFN relative to a reference symbol / slot / SFN, etc.)) that allows WTRU transmission and / or satellite reception of SRSp, and a set of satellite TA offset mapping relationships (each relationship is a mapping between a satellite TA offset value and an SRSp Tx time instance). At 904, the WTRU may determine a WTRU TA offset (e.g., a mapping from a zone ID of the WTRU and a zone to a TA). The WTRU may determine the zone of the WTRU's location (e.g., Figure 8 At 906, the WTRU may send a request to the network or satellite (e.g., in an RRC message) to activate an SRSp configuration with information about the WTRU's satellite ID and reference zone. At 908, the WTRU may receive activation of the requested SRSp configuration (or a new SRSp configuration) and an index to the satellite TA offset mapping relationship (e.g., in the configured set).

[0314] At 910, the WTRU may transmit one or more SRSps, each using the indicated time instance of the SRSp Tx time configuration and using the indicated SRSp configured resources. For each time instance, the WTRU may apply a TA to the SRSp transmission based on the WTRU TA offset and the satellite TA offset value (e.g., the sum) associated with the time instance according to the indicated satellite TA offset mapping relationship. For example, see Table 1 below:

[0315] Table 1 - Example Timing Advance

[0316] SRSp Tx time instance TA applied by the WTRU t0 WTRU TA Offset t1 WTRU TA offset + satellite TA offset 1 t2 WTRU TA offset + satellite TA offset 2

[0317] As shown above, when the WTRU is at a time instance (e.g., at Figure 8 When sending the SRSp at t0, t1 and t2 of FIG. 1 , the WTRU may apply the WTRU TA offset (basic offset) plus the satellite TA offset associated with each time instance (incremental offset).

[0318] For example, SRSp may be measured at different satellite positions that are sufficiently separated from each other (eg, separated by a predetermined threshold) to ensure accurate UL-based positioning.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor, the processor being configured to: receiving configuration information indicating a plurality of association sets, each association set including a plurality of corresponding time instances and a plurality of corresponding timing advance (TA) offsets; sending an indication of at least one of a mobile network node identity or WTRU location information; receiving an indication of a first association set of the plurality of association sets; as well as Transmitting a first sounding reference signal for positioning (SRSp) begins at a first time, wherein the first time is determined based on at least a first TA offset of the first association set and a first time instance associated with the first TA offset.

2. The WTRU of claim 1 , wherein the first SRSp transmission is sent to a satellite corresponding to the mobile network node identity or the WTRU location information.

3. The WTRU of claim 1 , wherein the first TA offset is based on a first satellite TA offset.

4. The WTRU of claim 1 , wherein the first time precedes the first time instance by a first TA value, wherein the first TA value is determined based on the first TA offset.

5. The WTRU of claim 4, wherein the first TA value is determined based on a sum of the first TA offset and a first WTRU TA offset, wherein the first WTRU TA offset is determined based on a first position of the WTRU.

6. The WTRU of claim 1 , wherein the first TA offset is selected from the first association set based on resources associated with the first time instance for the first SRSp transmission.

7. The WTRU of claim 1, wherein the first TA offset is selected based on an area in which the WTRU is located.

8. The WTRU of claim 1, wherein the configuration information comprises an SRSp resource set.

9. The WTRU of claim 8, wherein the first SRSp transmission is sent using at least one resource in the SRSp resource set.

10. The WTRU of claim 1 , wherein the processor is further configured to: receiving an indication of a second association set in the plurality of association sets; and The second sounding reference signal for positioning (SRSp) transmission is started at a second time, wherein the second time is determined based on at least a second TA offset of the second association set and a second time instance associated with the second TA offset.

11. The WTRU of claim 10, wherein the second TA offset is based on a second satellite TA offset.

12. The WTRU of claim 10, wherein the second time precedes the second time instance by a second TA value, wherein the second TA value is determined based on the second TA offset.

13. The WTRU of claim 12, wherein the second TA value is determined based on a sum of the second TA offset and a second WTRU TA offset, wherein the second WTRU TA offset is determined based on a second position of the WTRU or the first position of the WTRU.

14. A method performed in a wireless transmit receive unit (WTRU), the method comprising: receiving configuration information indicating a plurality of association sets, each association set including a plurality of corresponding time instances and a plurality of corresponding timing advance (TA) offsets; sending an indication of at least one of a mobile network node identity or WTRU location information; receiving an indication of a first association set of the plurality of association sets; as well as Transmitting a first sounding reference signal for positioning (SRSp) begins at a first time, wherein the first time is determined based on at least a first TA offset of the first association set and a first time instance associated with the first TA offset.

15. The method of claim 14, wherein the first SRSp transmission is sent to a satellite corresponding to the mobile network node identity or the WTRU location information. The method of claim 14 , wherein the first TA offset is based on a first satellite TA offset. 17 . The method of claim 14 , wherein the first time precedes the first time instance by a first TA value, wherein the first TA value is determined based on the first TA offset.

18. The method of claim 17, wherein the first TA value is determined based on a sum of the first TA offset and a first WTRU TA offset, wherein the first WTRU TA offset is determined based on a first location of the WTRU.

19. The method of claim 14, wherein the first TA offset is selected from the first association set based on resources associated with the first time instance for the first SRSp transmission.

20. The method of claim 14, wherein the first TA offset is selected based on an area in which the WTRU is located.

21. The method of claim 14, wherein the configuration information comprises a SRSp resource set.

22. The method of claim 21, wherein the first SRSp transmission is transmitted using at least one resource in the SRSp resource set.

23. The method of claim 14, wherein the processor is further configured to: receiving an indication of a second association set in the plurality of association sets; and The second sounding reference signal for positioning (SRSp) transmission is started at a second time, wherein the second time is determined based on at least a second TA offset of the second association set and a second time instance associated with the second TA offset.

24. The method of claim 23, wherein the second TA offset is based on a second satellite TA offset.

25. The method of claim 23, wherein the second time precedes the second time instance by a second TA value, wherein the second TA value is determined based on the second TA offset.

26. The method of claim 25, wherein the second TA value is determined based on a sum of the second TA offset and a second WTRU TA offset, wherein the second WTRU TA offset is determined based on a second position of the WTRU or the first position of the WTRU.

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