Method performed by user equipment in non-terrestrial network and user equipment

Abstract

A method performed by a user equipment in a non-terrestrial network and the user equipment are disclosed. A method performed by a UE includes: receiving a PRS from a base station in a DL subframe; determining a timestamp or a subframe index of the PRS in the DL subframe and a timestamp or a subframe index of a UE UL subframe closest to the DL subframe in time; determining a UE time difference from reception of the PRS to transmission of the SRS based on a timestamp or a subframe index of the PRS in the DL subframe and a timestamp or a subframe index of the UL subframe of the UE; generating an auxiliary report, wherein the auxiliary report comprises adjustment information for the LMF to calculate the UE time difference; providing the assistance report to the LMF; and reporting the SRS to the LMF based on a UE time difference.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 512,772, filed on July 10, 2023, and U.S. Non-Provisional Application No. 18 / 765,776, filed on July 8, 2024, the disclosures of which are incorporated herein by reference in their entireties as if fully set forth herein. Technical Field

[0003] The present disclosure generally relates to improving wireless communications for non-terrestrial networks (NTNs). More specifically, the subject matter disclosed herein relates to improvements to multiple round trip time (multiple RTT) techniques so that user equipment (UE) location can be verified through measurements performed by one satellite. Background Art

[0004] According to the 3rd Generation Partnership Project (3GPP) Release 18 (Rel-18) for NTN, a predefined level of accuracy for determining the location of a User Equipment (UE) should be provided in order to use certain services including the Public Warning System (PWS), Lawful Interception (LI) system, Emergency Services (EMS), and Billing and Rate Notification.

[0005] Relying on the Global Navigation Satellite System (GNSS) for precise positioning poses challenges due to weak signals in certain locations or the possibility of data tampering. For example, in some areas and locations, GNSS signals may be very weak and below the required noise margin. As a result, the reported UE position determined by its GNSS receiver may not be sufficiently accurate.

[0006] As another problem, UE location information may be maliciously tampered with by the UE itself or a third party.

[0007] These types of issues highlight the need for network-to-UE location verification methods that do not necessarily rely on GNSS data.

[0008] Among the available location verification methods, the multiple RTT method has been selected for network-verified UE location in NTN. The multiple RTT method under consideration for NTN is based on the following operations: a positioning reference signal (PRS) is sent from a base station (e.g., gNB) to the UE, and a sounding reference signal (SRS) is sent from the UE to the gNB. Based on these operations, the gNB measures the gNB receive (Rx)-transmit (Tx) time difference and reports the gNB Rx-Tx time difference to the location management function (LMF). Similarly, the UE individually measures the UE Rx-Tx time difference and reports the UE Rx-Tx time difference to the LMF. Thereafter, the LMF calculates the RTT. This operation is typically repeated multiple times.

[0009] However, this type of approach may have limitations in NTN scenarios, especially for low earth orbit (LEO) satellites, where the speed of the satellite significantly affects the timing of downlink (DL) and uplink (UL) subframes.

[0010] Therefore, improved measurement and reporting details are needed to support the multiple RTT approach for NTNs compared to terrestrial networks. Summary of the invention

[0011] To overcome the above-mentioned types of problems, the present disclosure provides systems and methods for improving UE Rx-Tx and gNB Rx-Tx time differences for a multiple RTT method applicable in NTN.

[0012] In the present invention, operations are provided for reporting assistance information (eg, Doppler frequency) from a UE to a LMF in order to provide an enhanced multiple RTT method for single satellite, network-verified UE location in an NTN.

[0013] For example, the UE may report to the LMF the difference between the Doppler frequency measured when receiving PRS (or channel state information reference signal (CSI-RS)) in DL subframe #i (or UL subframe #j) and the Doppler frequency measured when transmitting SRS in UL subframe #k. When the UE receives PRS (or CSI-RS), the UE may simply calculate the Doppler frequency at DL subframe #i, and when the UE transmits SRS, the UE may also calculate the Doppler frequency at UL subframe #k, and may report the difference between the two values ​​to the LMF. The reported value may be positive or negative, depending on whether the Doppler frequency increases or decreases during the reception of PRS and the transmission of SRS.

[0014] The UE may also report UE Rx-Tx and offset values.

[0015] The UE may also separately report the Doppler frequency measured at DL subframe #i or at uplink subframe #k to the LMF.

[0016] Thus, embodiments of the present disclosure significantly improve the reliability of UE location verification in NTN environments, addressing the challenges presented by such a setup (including the mobility of satellites). The present disclosure provides a robust framework for UE location verification that is superior to previous approaches by providing improved accuracy for critical services without relying on GNSS data. Furthermore, UE location verification can be achieved using one satellite without relying on multiple transmit and receive points (TRPs) on the network.

[0017] According to an embodiment, a method for a UE in an NTN is provided. The method includes: receiving a PRS from a base station in a DL subframe; determining a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of a UE UL subframe that is temporally closest to the DL subframe; determining a UE time difference from receiving the PRS to sending an SRS based on the timestamp or subframe index of the PRS in the DL subframe and the timestamp or subframe index of the UE UL subframe; generating an auxiliary report, the auxiliary report including adjustment information for an LMF to calculate the UE time difference; providing the auxiliary report to the LMF; and reporting an SRS to the LMF based on the UE time difference.

[0018] According to an embodiment, a UE used in an NTN is provided. The UE includes at least one processor; and a memory storing instructions, wherein when the instructions are executed by the at least one processor, the UE is controlled to perform the following operations: receiving a PRS from a base station in a DL subframe; determining a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of a UE UL subframe that is temporally closest to the DL subframe; determining a UE time difference from receiving the PRS to sending an SRS based on the timestamp or subframe index of the PRS in the DL subframe and the timestamp or subframe index of the UE UL subframe; generating an auxiliary report, the auxiliary report including adjustment information for an LMF to calculate the UE time difference; providing the auxiliary report to the LMF; and reporting the SRS to the LMF based on the UE time difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the following sections, various aspects of the subject matter disclosed herein will be described with reference to exemplary embodiments shown in the accompanying drawings, in which:

[0020] Figure 1 is a diagram showing an NTN network environment according to an embodiment;

[0021] Figure 2 illustrates network signaling operations for performing RTT measurements according to an embodiment;

[0022] Figure 3 is a graph depicting a DL subframe varying over time according to an embodiment;

[0023] Figure 4 shows the DL subframe length observed by a UE when a satellite in a LEO-600NTN scenario passes overhead, according to an embodiment;

[0024] Figure 5 is a graph depicting UL subframe variation over time according to an embodiment.

[0025] Figure 6 A timing diagram comparing gNB DL and UL subframes with UE DL and UL subframes according to an embodiment is shown;

[0026] Figure 7 shows the UE Rx-Tx time difference according to an embodiment;

[0027] Figure 8 shows the gNB Rx-Tx time difference according to an embodiment;

[0028] Fig. 9 An example of UE reporting using predicted Doppler according to an embodiment is shown;

[0029] Fig.10 is a flow chart illustrating a method performed by a UE in an NTN environment according to an embodiment;

[0030] Fig.11 is a block diagram of an electronic device in a network environment according to an embodiment; and

[0031] Fig.12 A system including a UE and a gNB communicating with each other is shown. DETAILED DESCRIPTION

[0032] In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the present disclosure. However, those skilled in the art will appreciate that the disclosed aspects may be practiced without these specific details. In other cases, well-known methods, processes, components, and circuits are not described in detail to avoid obscuring the subject matter disclosed herein.

[0033] References throughout this specification to "one embodiment" or "an embodiment" refer to specific features, structures, or characteristics described in conjunction with the embodiment that may be included in at least one embodiment disclosed herein. Therefore, the phrases "in one embodiment" or "in an embodiment" or "according to an embodiment" (or other phrases with similar meanings) that appear in various places throughout this specification may not necessarily all refer to the same embodiment. In addition, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this regard, as used herein, the word "exemplary" means "used as an example, instance, or illustration." Any embodiment described herein as "exemplary" should not be interpreted as necessarily being preferred or advantageous over other embodiments. In addition, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In addition, depending on the context discussed herein, singular terms may include corresponding plural forms, and plural terms may include corresponding singular forms.

[0034] In addition, depending on the context discussed herein, singular terms may include corresponding plural forms, and plural terms may include corresponding singular forms. It should also be noted that the various drawings (including component drawings) shown and discussed herein are for illustrative purposes only and are not drawn to scale. For example, for clarity, the size of some elements may be exaggerated relative to other elements. In addition, if deemed appropriate, reference numerals are repeated in the drawings to indicate corresponding and / or similar elements.

[0035] The terms used herein are only used for the purpose of describing some example embodiments and are not intended to limit the claimed subject matter. As used herein, unless the context clearly indicates otherwise, the singular form is intended to also include the plural form. It will be further understood that when used in this specification, the terms "include" and / or "comprise" specify the presence of features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0036] It should be understood that when an element or layer is referred to as being on, "connected to" or "coupled to" another element or layer, it may be directly on, connected to or coupled to another element or layer, or there may be intermediate elements or layers. Conversely, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element or layer, there are no intermediate elements or layers. The same reference numerals always represent the same element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] As used herein, the terms "first", "second", etc. are used as labels for the nouns preceding them, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.) unless explicitly defined as such. In addition, the same reference numerals may be used in two or more figures to refer to parts, components, blocks, circuits, units, or modules having the same or similar functions. However, such use is only for simplicity of illustration and ease of discussion; this does not imply that the construction or architectural details of such components or units are the same in all embodiments, or that such commonly referenced parts / modules are the only way to implement some example embodiments disclosed herein.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such in this article.

[0039] As used herein, the term "module" refers to any combination of software, firmware, and / or hardware configured to provide the functionality described herein in conjunction with the module. For example, software may be implemented as a software package, code, and / or instruction set or instructions, and the term "hardware" as used in any embodiment described herein may include, for example, individually or in any combination, components, hardwired circuits, programmable circuits, state machine circuits, and / or firmware storing instructions executed by programmable circuits. Modules may be implemented collectively or individually as circuits that form part of a larger system, such as, but not limited to, an integrated circuit (IC), a system on a chip (SoC), a component, etc.

[0040] In 3GPP New Radio (NR), when a UE attaches to a mobile network, the Radio Access Network (RAN) selects an appropriate Core Network (CN) for the UE. To do this, the RAN considers UE attributes such as the UE Identifier (ID), the UE's selected Public Land Mobile Network (PLMN) and / or the UE's location information (including the serving cell known to the serving RAN node).

[0041] NTNs typically deploy very large cells over large areas that may cover two or even more different countries. In this case, there may be different CNs belonging to two or more countries connected to the same NTN RAN (e.g., a multi-operator CN (MOCN) sharing scenario). In this case, it may not be possible to determine the appropriate CN for a connected UE, especially when the UE is near a national border, because the serving cell information may not be granular and / or accurate enough.

[0042] There is also a risk that a malicious UE could fraudulently change its selected PLMN to connect to a different CN.

[0043] Upon such a malicious attempt, the Access and Mobility Management Function (AMF) is expected to disconnect the UE and inform the RAN nodes via appropriate Next Generation Application Protocol (NGAP) values ​​so that the RAN can take appropriate action on subsequent connection attempts by the same UE.

[0044] Although the UE may send GNSS measurements to the RAN via Radio Resource Control (RRC) for the network to verify the UE position, this approach also has disadvantages.

[0045] For example, in the same way that a malicious UE can falsify its selected PLMN, a malicious UE can also falsify its GNSS measurements. Furthermore, sending GNSS measurements to the RAN via RRC before Non-Access Stratum (NAS) security is established raises serious privacy and security issues. Furthermore, even after NAS security is established, user consent may be required to obtain UE location information, depending on regional regulations and policies.

[0046] However, regardless of the type of problem described above, at least some of the information provided by the UE to the network should be considered trustworthy. Otherwise, it is virtually impossible to verify the UE location in a reliable manner.

[0047] Depending on national or regional regulatory requirements applicable to the UE, in a fifth generation (5G) NR system with NTN satellite access, determining the location of the UE may be necessary to support services such as routing traffic and supporting emergency calls.

[0048] Network operators supporting NTN should know the location of the UE accurately in order to select the appropriate CN for the UE, so that services subject to national regulations or other operational constraints can be supported. For example, the NTN Rel-18 framework has identified services that require accurate location information: PWS, LI, EMS, and billing and tariff notification.

[0049] However, as described above, the location information reported by the UE (e.g., location information determined using a GNSS receiver) may be intentionally (e.g., maliciously tampered with by the user or by a third party) or unintentionally (e.g., caused by interference) erroneous, and therefore, according to the Rel-18 NTN work item, the location information reported by the UE cannot be considered trustworthy by the network operator.

[0050] Although 3GPP has defined a network-based function for verifying the reported UE location using an identifier (e.g., cell ID) of a serving cell of a terrestrial network, the radio cells in a cellular NTN are typically much larger than those of a cellular terrestrial network and may cover a border between two or more countries. Therefore, this type of cell ID information may not be sufficient to distinguish the country in which the UE is located.

[0051] Therefore, the present disclosure provides an improved multiple RTT method to meet the NTN requirements.

[0052] Figure 1 is a diagram showing an NTN network environment according to an embodiment.

[0053] Reference Figure 1 , the network 100 may be a multiple access wireless communication system supporting broadcast services, such as NTN. The network 100 may be designed to support one or more standards, such as 3GPP. The network 100 includes a UE 101, a satellite 102, and a gNB 103.

[0054] UE 101 may be capable of sending, receiving, storing and processing data.UE 101 may be an electronic device, such as a mobile device, a laptop computer or other equipment, including a transceiver system.

[0055] Satellite 102 may be an orbiting platform capable of sending and receiving data to and from UE 101 and gNB 103. Satellite 102 may communicate with UE 101, wherein satellite 102 may send and receive data to and from UE 101 via communication link 104. Communication link 104 may include UL and DL data transmissions.

[0056] The gNB 103 may include an antenna capable of sending and receiving data to and from the satellite 102. The gNB 103 may be connected to or associated with a base station or logical radio node. The gNB 103 may communicate with the satellite 102 via a communication link 105. The communication link 105 may include UL and DL data transmissions.

[0057] A cell 106 may be a geographic area in which UE 101 and other UEs can communicate with satellite 102. The size of a cell 106 may vary depending on the location of satellite 102 relative to the earth. For example, in one embodiment, a geostationary equatorial orbit (GEO) satellite may allow for a larger cell 106 area, which may be between 200 kilometers (km) and 3500 km in diameter. Medium earth orbits (MEO) and LEO may have smaller associated cell 106 sizes. In addition, the distance from satellite 102 to the earth may affect the transmission time for sending and receiving data between UE 101 and satellite 102 and between satellite 102 and gateway 103.

[0058] Figure 2 Network signaling operations for performing RTT measurements according to an embodiment are shown.

[0059] refer to Figure 2 , a gNB and a UE are shown. The gNB and the UE may correspond to gNB 103 and UE 101, respectively.

[0060] The multiple RTT method for NTN can be based on the following operations: sending PRS from the gNB to the UE, and sending SRS from the UE to the gNB. Based on these operations, the gNB and the UE make measurements and report the measurements to the LMF. The LMF can calculate the RTT according to the following formula (1):

[0061] RTT=(t2-t1)+t3–t4) (1)

[0062] In order for the LMF to calculate (t2-t1), the gNB reports the gNB Rx-Tx time difference (in Figure 2 Similarly, in order for the LMF to calculate (t3 to t4), the UE reports the UE Rx-Tx time difference (in Figure 2202).

[0063] In the context of mobile telecommunications, and in particular within the 3GPP standards for 5G networks, the LMF is the functional entity responsible for managing the location of the UE and the services provided to the UE. The LMF can be used to determine the location of the UE based on various inputs and measurements, such as those from the RAN and other location measurement units. The LMF processes information to estimate and report the location of the UE, thereby supporting various applications and services that require accurate location information, including EMS, location-based services, and network management tasks.

[0064] The LMF may reside in the CN of the 5G system, interfacing with other CN functions such as the AMF and unified data management (UDM) functions. The LMF may be hosted in a storage device on a network node (e.g., a gNB, UE, satellite, server, or another electronic device). The LMF may also interface with the RAN to obtain measurements and information from network nodes to perform its location calculations.

[0065] In the case of an NTN environment operating with LEO satellites, the dynamic nature of LEO satellite movement presents significant challenges to the communication protocols, particularly in terms of timing and signal processing. For example, in a LEO-600 scenario (where the satellite orbits approximately 600 km above the Earth's surface), the satellite may be moving at a relatively fast speed of 7.56 km per second. However, such rapid movement may have a significant impact on the DL subframes received by the UE from the gNB, causing changes in the perceived duration of these subframes due to the Doppler effect. For example, at such high speeds, due to the Doppler effect, when the satellite is closer to or farther away from the UE, the DL subframe sent by the gNB is received at the UE with a subframe length that is different from the subframe length sent. In other words, from the UE's perspective, the DL subframe shrinks or expands.

[0066] Figure 3 is a graph depicting DL subframes varying over time according to an embodiment.

[0067] refer to Figure 3 , shows the amount of DL subframe contraction or expansion from the UE's perspective as the satellite gets closer to or farther away from the UE in a transparent payload.

[0068] Figure 3Assume that the UE is located in the orbital plane of the LEO-600 satellite. Therefore, the satellite remains in the field of view of the UE for approximately 13 minutes while in orbit in the LEO-600 satellite orbital plane. During this period, the relative speed between the satellite and the UE causes the DL subframe duration to vary. Specifically, as the satellite approaches the UE, the DL subframe observed by the UE appears to shrink, being up to 48 nanoseconds (ns) shorter than the standard 1 millisecond (ms) duration. This effect is most pronounced when the satellite is directly overhead, when the DL subframe duration is close to the nominal value of approximately 1 ms. In addition, as the satellite moves away from the UE, the observed DL subframe duration expands, exceeding the standard duration by approximately 48ns.

[0069] This variation in DL subframe duration presents unique challenges to accurately determining timing and, therefore, the location of the UE. Methods for timing and location estimation designed for relatively static terrestrial network environments may not be directly applicable to the highly dynamic NTN context (since DL subframe variations are more pronounced in LEO NTN environments).

[0070] Figure 4 DL subframe lengths observed by a UE when a satellite passes overhead in a LEO-600NTN scenario are shown according to an embodiment.

[0071] refer to Figure 4 , which helps visualize the Doppler effect on signal timing, where the length of the DL subframe shrinks as the satellite approaches the UE and expands as the satellite moves away. Specifically, as the satellite gets closer to the UE, the DL subframe can be around 1ms-48ns. This corresponds to Figure 3 On the other hand, as the satellite moves further away from the UE, the DL subframe can be approximately 1ms+48ns. This corresponds to Figure 3 In addition, when the satellite is above the UE, the Doppler effect is least significant and the DL subframe can be ~1 ms. This corresponds to Figure 3 ~6.5 minutes.

[0072] The measurement of the UE's Rx-Tx time difference is a process that typically spans tens of subframes. Due to the speed of the satellite, the accumulated measurement error in the DL subframe length after, for example, 20 subframes may be close to about 1us. If the method for measuring the UE Rx-Tx time difference only relies on counting the number of DL subframes and assuming a constant subframe length, it may cause significant inaccuracies in the UE position determined by the multiple RTT method.

[0073] Taking this into account, the total absolute value of the UE Rx-Tx time difference should be reported to the network, in particular to the LMF, to ensure measurement accuracy.

[0074] 3GPP TS 38.133 for Rel-18 outlines the process of absolute UE Rx-Tx time difference reporting mapping for terrestrial networks in section 10.1.25.3.1, where the assumption of fixed DL subframe duration is reasonable due to stationary gNBs. In this terrestrial context, the reporting range of absolute UE Rx-Tx time difference measurements is from -985024*T c Leap to 985024*T c , the resolution step is 2 k *T c (where T c is the transmission time interval, and k varies between 0 and 5, depending on whether the measurement is performed in frequency range 1 (FR1) or frequency range 2 (FR2). This means that the reported UE Rx-Tx time difference values ​​lie between approximately -0.5 ms and +0.5 ms with varying resolution steps. The calculation of the additional component of the UE Rx-Tx time difference is delegated to the LMF, which knows the indices of the subframes in which the UE receives and transmits PRS and SRS, allowing the calculation of the total UE Rx-Tx time difference under the assumption of constant subframe duration in the terrestrial network.

[0075] On the other hand, in NTN scenarios, such an assumption is not valid due to the variability of the subframe duration caused by the relatively high speed of the satellite. Therefore, the UE must report the total absolute value of the UE Rx-Tx time difference. To accommodate this, an extension of the reporting range of the absolute UE Rx-Tx time difference measurement should be used, so that only positive values ​​are covered. If the range is extended to cover from 0 to 2 29 *T c , the reporting capability can support absolute UE Rx-Tx time difference measurements up to 273ms. This extension will fully account for the distance variation between receiving PRS and transmitting SRS without the need to adjust the 2 k *T c The current resolution step size.

[0076] The above analysis of the LEO-600 scenario shows that the length of the DL subframe perceived by the UE can vary by as much as + / -48ns due to the high speed of the satellite. The situation can become even more complicated when the UL subframe is considered.

[0077] Figure 5 is a graph depicting UL subframe variation over time according to an embodiment.

[0078] refer to Figure 5, since the UE compensates the timing based on the DL signal it receives, the UL subframe timing observed by the gNB may experience up to twice the variation observed in the DL subframe, which means the variation may be as high as 96ns. This phenomenon is caused by Figure 5 The graphical representation shown in , which illustrates the amount by which the UL subframe is contracted or extended when the position of the satellite relative to the UE changes in a transparent payload scenario.

[0079] However, in this context, there are some factors to consider regarding the UE Rx-Tx time difference.

[0080] As a first factor, the UE can autonomously adjust its timing advance (TA) and subframe timing, which are informed by the GNSS position and the ephemeris of the satellite. This autonomy can be used to maintain synchronization between the UE and satellite timing.

[0081] As a second factor, a TA Command (TAC) may be issued by the gNB when the gNB detects that the UE's timing drifts and loses synchronization.

[0082] Figure 6 A timing diagram comparing gNB DL and UL subframes with UE DL and UL subframes according to an embodiment is shown.

[0083] refer to Figure 6 ,The timing diagram reflects the scenario where the satellite is getting closer to the UE. As shown therein, the UE observes that the length of the received DL subframe is shortened by δms.

[0084] For UL transmissions, without loss of generality, it is assumed that the UE does not pre-compensate the length of the UL subframe for the observed Doppler.Uplink frame transmission occurs at the TA calculated using equation (2) before the first detected path (in time) of the corresponding downlink frame is received from the reference cell.

[0085]

[0086] UE can keep updated based on UE mobility and satellite trajectory

[0087] The UE may also receive TAC from the network to update N TA .

[0088] Figure 7 UE Rx-Tx time difference according to an embodiment is shown. More specifically, Figure 7 An example of how to perform UE Rx-Tx measurements at the UE is shown.

[0089] refer to Figure 7, the gNB is configured by the LMF to send PRS (or CSI-RS) to the target UE. In addition, the target UE is configured by the LMF to send SRS to the gNB. SRS transmission should occur within a certain range of the reception of PRS from the UE. For example, SRS transmission should occur within + / -20ms from the reception of PRS. This helps to avoid any timing drift due to UE clock drift and / or subframe timing contraction / expansion due to Doppler as described above.

[0090] The UE then measures the UE Rx-Tx time difference, which can be defined as T UE-Rx -T UE-Tx ,like Figure 7 shown.

[0091] Here, T UE-Rx is the UE reception timing of DL subframe #i from transmission point (TP), which is defined by the first detection path of DL subframe #i in time. UE-Tx is the UE transmission timing of the UL subframe #j that is closest in time to the DL subframe #i received from the TP.

[0092] A number of PRS or CSI-RS used for tracking resources (eg, as indicated by network higher layers or LMF) may be used to determine the start of a subframe of the first arrival path for the TP.

[0093] The UE then reports the measured UE Rx-Tx to the network higher layers or LMF.

[0094] although Figure 7 An example is shown where the value of UE Rx-Tx is positive, but the value of UE Rx-Tx may be negative or positive. For example, depending on the value of TA applied to UL transmission, if UL subframe #j occurs after DL subframe #i, the value of UE Rx-Tx will be negative.

[0095] In addition to the UE Rx-Tx, the UE may report to the network higher layers or the LMF at least one of the following: 1) subframe indices #j and #k, where subframe #k is the subframe in which the UE transmits SRS to the gNB, or 2) an offset value indicating the time offset between the UE transmit timing of UL subframe #j and the UE transmit timing of UL subframe #k, such as Figure 7 shown.

[0096] In order to enable the network or LMF to accurately calculate the effective time difference between the UE receiving PRS and the same UE sending SRS, the UE can send an auxiliary report containing various adjustment information to the network higher layer or LMF.

[0097] In the following, various examples of auxiliary reports are provided.

[0098] Time-based auxiliary reporting

[0099] Time based option 1:

[0100] According to an embodiment, the UE reports to the LMF the aggregate value of all TA adjustments that have been applied to the TA between the UE receiving PRS (or CSI-RS) in DL subframe #i (or UL subframe #j) and sending SRS in UL subframe #k. The UE may add all autonomous timing adjustments and all N TA Adjustments. These values ​​can be positive or negative, and the total can also be positive or negative.

[0101] The UE then reports the aggregate value to the LMF. The UE also reports the UE Rx-Tx and the offset value as described above.

[0102] For example, the UE may report the aggregate value of all timing adjustments, which is expressed as As shown in equation (3).

[0103]

[0104] Time based option 2:

[0105] According to an embodiment, the UE reports to the LMF the aggregate value of all TA adjustments that the UE has applied to the TA between TA seconds before receiving the PRS (or CSI-RS) in the DL channel (i.e., equivalently at UL subframe #i) and sending the SRS in UL subframe #k. The UE may add all autonomous timing adjustments and all N TA Adjustments. These values ​​can be positive or negative, and the total can also be positive or negative.

[0106] The UE then reports the aggregate value to the LMF. The UE also reports the UE Rx-Tx and the offset value as explained above.

[0107] For example, the UE may report the aggregate value of all timing adjustments, which is expressed as As shown in equation (4).

[0108]

[0109] For time-based Option 1 and Option 2, new signaling may be defined to report the aggregate TA value. According to an embodiment, a Media Access Control (MAC) Control Element (CE) similar to the MAC CE for reporting the TA command may be defined with a longer bit field to report the aggregate TA value. The UE may report the aggregate TA via this MAC CE, and the gNB will send it to the LMF via LTE Positioning Protocol (LPP) signaling.

[0110] Alternatively, RRC signaling may be used instead of MAC CE. However, if RRC signaling is used, the LMF may have to compensate for satellite motion to some extent.

[0111] Doppler-based auxiliary reporting

[0112] Doppler based option 1:

[0113] According to an embodiment, the UE may report to the LMF the difference between the Doppler frequency measured when receiving PRS (or CSI-RS) in DL subframe #i (or UL subframe #j) and the Doppler frequency measured when sending SRS in UL subframe #k. When the UE receives PRS (or CSI-RS), the UE may calculate the Doppler frequency at DL subframe #i, and when the UE sends SRS, the UE may also calculate the Doppler frequency at UL subframe #k.

[0114] Thereafter, the difference between the two values ​​may be reported to the LMF. The reported value may be positive or negative, depending on whether the Doppler frequency increases or decreases when receiving the PRS and transmitting the SRS.

[0115] The UE may also report the UE Rx-Tx and the offset value as explained above.

[0116] The UE may also separately report the Doppler frequency measured at DL subframe #i or at UL subframe #k to the LMF.

[0117] For example, the UE may report the difference in Doppler frequency (eg, in parts per million (ppm)), which is represented as ΔF d , as shown in equation (5).

[0118] ΔF d =F d (UL SF#k)-F d (UL SF#j) (5)

[0119] In equation (5), F d (UL SF#k) and F d (UL SF#j) denotes Doppler frequencies measured by the UE at UL subframe #k and UL subframe #j, respectively.

[0120] Doppler based option 2:

[0121] According to an embodiment, the UE may report to the LMF the difference between the Doppler frequency measured at TA seconds before receiving the PRS (or CSI-RS) in the DL channel (ie, equivalently at UL subframe #i) and the Doppler frequency measured when the SRS is transmitted in UL subframe #k. The UE may calculate the Doppler frequency TA seconds before it receives the PRS (or CSI-RS) and when it transmits the SRS.

[0122] Thereafter, the difference between the two values ​​is reported to the LMF. The reported value can be positive or negative, depending on whether the Doppler frequency increases or decreases when receiving PRS and transmitting SRS.

[0123] The UE may also report UERX_TX and an offset value as explained above.

[0124] The UE may also separately report the Doppler frequency measured at UL subframe #i or at UL subframe #k to the LMF.

[0125] For example, the UE may report the difference in Doppler frequency, which is denoted as ΔF d , as shown in equation (6).

[0126] ΔF d =F d (UL SF#k)-F d (UL SF#i) (6)

[0127] In equation (6), F d (UL SF#k) and F d (UL SF#i) denotes Doppler frequencies measured by the UE at UL subframe #k and UL subframe #i, respectively.

[0128] For Doppler based options 1 and 2, the positioning report includes reporting Doppler values ​​or differential Doppler frequency values ​​in addition to the normal measurements used for positioning.

[0129] Figure 8 FIG. 1 shows the gNB Rx-Tx time difference according to an embodiment. More specifically, Figure 8 An example of how gNB Rx-Tx measurements are performed at the gNB is shown.

[0130] refer to Figure 8 , the gNB is configured by the LMF to send PRS (or CSI-RS) to the target UE. The target UE is also configured by the LMF to send SRS to the gNB. The gNB Rx-Tx time difference can be defined as T gNB-Rx -TgNB-Tx ,like Figure 8 shown.

[0131] T gNB-Rx is the gNB reception timing of UL subframe #k including the SRS associated with the UE defined by the first detection path in time, and T gNB-Tx is the gNB transmit timing of DL subframe #m that is closest in time to subframe #k received from the UE.

[0132] A plurality of SRS resources may be used to determine the start of one subframe including an SRS.

[0133] The gNB reports the Rx-Tx time difference to the LMF. Similar to when the UE reports the UE Rx-Tx time difference, a new field (such as Doppler frequency difference) may be added, which is defined for reporting the Rx-Tx time difference.

[0134] Fig. 9 An example of UE reporting using predicted Doppler according to an embodiment is shown. More specifically, Fig. 9 It is shown that the UE predicts the Doppler frequency at UL subframe #k at one subframe after subframe #j.

[0135] Reference Fig. 9 , after the UE receives the ephemeris information of the satellite (and neighboring satellites) in the system information from the network, the UE will be able to accurately predict the trajectory of the satellite (or multiple satellites) within a sufficient amount of time in the future (e.g., 10 seconds).

[0136] According to an embodiment, based on the ephemeris and predicted trajectory of the satellite, the UE predicts the Doppler frequency at UL subframe #k well in advance. Since the UE Rx-Tx measurement is ready at UL subframe #j, the UE can report the UE Rx-Tx and differential Doppler frequency value relatively quickly after UL subframe #j according to the Doppler-based Option 1 or Option 2 as described above. Although Fig. 9 It is shown that the prediction and reporting are performed at the 3rd subframe after subframe #j, but the present disclosure is not limited thereto.

[0137] Although 3GPP Rel-17 requires the UE to send SRS for UE Rx-Tx measurement within a maximum of + / -160ms of the UE receiving the DL PRS (or CSI-RS), for NTN scenarios such as LEO (where satellites typically move at relatively high speeds), the UE may observe Doppler frequencies up to 48kHz. Therefore, according to an embodiment, for NTN scenarios, the + / -160ms requirement may be lowered. For example, a lower value in the range of + / -10ms to + / -20ms is more suitable for NTN scenarios.

[0138] As mentioned above, where applicable, the UE may send multiple SRSs to improve the accuracy of the measurement. Generally, there are three options for how the UE reports the assistance information of multiple SRSs.

[0139] 1. Individual reporting: Where applicable, the UE reports assistance information individually for each SRS transmission.

[0140] 2. Selective reporting: The UE arbitrarily reports assistance information only for one SRS, and the LMF assumes that this one assistance report is valid for all individual SRS transmissions.

[0141] 3. Average report: The UE calculates the average of the adjustment information of the auxiliary reports of all SRS transmissions and reports the average to the LMF.

[0142] For selective reporting and average reporting, new measurements may be defined for the selection operation and / or the average operation, although this may be determined by the network. Additionally, the gNB may signal which SRS are jointly transmitted and may be jointly processed (e.g., definition of a "queue" of SRS).

[0143] Fig.10 is a flow chart illustrating a method performed by a UE in an NTN environment according to an embodiment.

[0144] refer to Fig.10 In step 1001, a PRS is received by a UE. The PRS may be received from a base station in a DL. For example, Figure 7 As shown, PRS is received in subframe #i.

[0145] In step 1002, the timestamp or subframe index of the PRS in the DL is determined, and the timestamp or subframe index of the UE UL subframe that is closest in time to the DL is determined. Figure 7 As shown in , the timestamp or subframe index of the PRS in the DL subframe #i is determined, and the timestamp or subframe index of the UL subframe #j is determined.

[0146] In step 1003, the UE time difference from receiving the PRS to sending the SRS may be determined based on the timestamp or subframe index of the PRS in the DL and the timestamp or subframe index of the UE UL subframe.

[0147] In step 1004, the UE generates an assistance report, which includes adjustment information for the LMF to calculate the UE time difference. For example, the assistance report can be generated according to the time-based option 1, the time-based option 2, the Doppler-based option 1, or the Doppler-based option 2 as described above.

[0148] In step 1005, the UE provides an assistance report to the LMF, for example via a MAC CE.

[0149] In step 1006, the SRS is reported to the LMF based on the UE time difference. As described above, the LMF may be structurally implemented by a network node, a terminal, a UE, a satellite, a base station, or any other device connected to the network.

[0150] Fig.11 1 is a block diagram of an electronic device in a network environment 1100 according to an embodiment. For example, Fig.11 The electronic device 1101 may correspond to Figure 1 One or more of the UE 101, satellite 102 and / or gNB 103 shown. One or more of the components shown in the electronic device 1101 may be included in one or more of the UE 101, satellite 102 and / or gNB 103.

[0151] Reference Fig.11 , the electronic device 1101 in the network environment 1100 may communicate with the electronic device 1102 via a first network 1198 (e.g., a short-range wireless communication network), or communicate with the electronic device 1104 or the server 1108 via a second network 1199 (e.g., a long-range wireless communication network). The electronic device 1101 may communicate with the electronic device 1104 via the server 1108. The electronic device 1101 may include a processor 1120, a memory 1130, an input device 1150, a sound output device 1155, a display device 1160, an audio module 1170, a sensor module 1176, an interface 1177, a haptic module 1179, a camera module 1180, a power management module 1188, a battery 1189, a communication module 1190, a subscriber identification module (SIM) card 1196, or an antenna module 1197. In one embodiment, at least one of the above components (e.g., display device 1160 or camera module 1180) may be omitted from electronic device 1101, or one or more other components may be added to electronic device 1101. Some of the above components may be implemented as a single integrated circuit (IC). For example, sensor module 1176 (e.g., fingerprint sensor, iris sensor, or illumination sensor) may be embedded in display device 1160 (e.g., display).

[0152] The processor 1120 may run software (eg, program 1140) to control at least one other component (eg, hardware component or software component) of the electronic device 1101 connected to the processor 1120, and may perform various data processing or calculations (eg, Fig.10 ).

[0153] As at least part of the data processing or calculation, the processor 1120 may load commands or data received from another component (e.g., the sensor module 1176 or the communication module 1190) into the volatile memory 1132, process the commands or data stored in the volatile memory 1132, and store the resultant data in the non-volatile memory 1134. The processor 1120 may include a main processor 1121 (e.g., a central processing unit (CPU) or an application processor (AP)) and an auxiliary processor 1123 (e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operationally independent or combined with the main processor 1121. Additionally or alternatively, the auxiliary processor 1123 may be adapted to consume less power than the main processor 1121, or to perform a specific function. The auxiliary processor 1123 may be implemented to be separate from the main processor 1121, or to be implemented as part of the main processor 1121.

[0154] When the main processor 1121 is in an inactive (e.g., sleep) state, the auxiliary processor 1123 (rather than the main processor 1121) may control at least some of the functions or states related to at least one component (e.g., display device 1160, sensor module 1176, or communication module 1190) among the components of the electronic device 1101, or when the main processor 1121 is in an active state (e.g., running an application), the auxiliary processor 1123 may control at least some of the functions or states related to at least one component (e.g., display device 1160, sensor module 1176, or communication module 1190) together with the main processor 1121. The auxiliary processor 1123 (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., camera module 1180 or communication module 1190) that is functionally related to the auxiliary processor 1123.

[0155] The memory 1130 may store various data used by at least one component of the electronic device 1101 (e.g., the processor 1120 or the sensor module 1176). The various data may include, for example, software (e.g., program 1140) and input data or output data for commands related thereto. The memory 1130 may include a volatile memory 1132 or a nonvolatile memory 1134. The nonvolatile memory 1134 may include an internal memory 1136 and an external memory 1138.

[0156] The program 1140 may be stored as software in the memory 1130 , and may include, for example, an operating system (OS) 1142 , middleware 1144 , or an application 1146 .

[0157] The input device 1150 may receive commands or data to be used by other components (eg, the processor 1120) of the electronic device 1101 from outside the electronic device 1101 (eg, a user). The input device 1150 may include, for example, a microphone, a mouse, or a keyboard.

[0158] The sound output device 1155 can output a sound signal to the outside of the electronic device 1101. The sound output device 1155 may include, for example, a speaker or a receiver. The speaker can be used for general purposes such as playing multimedia or playing records, and the receiver can be used to receive incoming calls. The receiver can be implemented as a separate part from the speaker, or as part of the speaker.

[0159] The display device 1160 may visually provide information to the outside (e.g., user) of the electronic device 1101. The display device 1160 may include, for example, a display, a holographic device, or a projector, and a control circuit for controlling a corresponding one of the display, the holographic device, and the projector. The display device 1160 may include a touch circuit adapted to detect a touch or a sensor circuit (e.g., a pressure sensor) adapted to measure the strength of a force caused by a touch.

[0160] The audio module 1170 can convert sound into an electrical signal or vice versa. The audio module 1170 can obtain sound via the input device 1150 or output sound via the sound output device 1155 or an earphone of an external electronic device 1102 directly (eg, wired) or wirelessly connected to the electronic device 1101.

[0161] The sensor module 1176 may detect an operating state (e.g., power or temperature) of the electronic device 1101 or an environmental state (e.g., a user's state) outside the electronic device 1101, and then generate an electrical signal or data value corresponding to the detected state. The sensor module 1176 may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illumination sensor.

[0162] The interface 1177 may support one or more specific protocols to be used to connect the electronic device 1101 directly (e.g., wired) or wirelessly with the external electronic device 1102. The interface 1177 may include, for example, a high-definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface.

[0163] The connection end 1178 may include a connector via which the electronic device 1101 may be physically connected to the external electronic device 1102. The connection end 1178 may include, for example, an HDMI connector, a USB connector, an SD card connector, or an audio connector (eg, a headphone connector).

[0164] The haptic module 1179 may convert the electrical signal into mechanical stimulation (eg, vibration or motion) or electrical stimulation that can be recognized by the user via tactile or kinesthetic sense. The haptic module 1179 may include, for example, a motor, a piezoelectric element, or an electrical stimulator.

[0165] The camera module 1180 may capture still images or moving images. The camera module 1180 may include one or more lenses, an image sensor, an image signal processor, or a flash. The power management module 1188 may manage the power supply to the electronic device 1101. The power management module 1188 may be implemented as at least part of a power management integrated circuit (PMIC), for example.

[0166] The battery 1189 may power at least one component of the electronic device 1101. The battery 1189 may include, for example, a non-rechargeable primary battery, a rechargeable secondary battery, or a fuel cell.

[0167] The communication module 1190 may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device 1101 and an external electronic device (e.g., electronic device 1102, electronic device 1104, or server 1108), and perform communication via the established communication channel. The communication module 1190 may include one or more communication processors capable of operating independently from the processor 1120 (e.g., AP), and support direct (e.g., wired) communication or wireless communication. The communication module 1190 may include a wireless communication module 1192 (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module 1194 (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate via a first network 1198 (e.g., a short-range communication network such as Bluetooth TM, Wireless Fidelity (Wi-Fi) Direct, or Infrared Data Association (IrDA) standards) or a second network 1199 (e.g., a long-distance communication network such as a cellular network, the Internet, or a computer network (e.g., a LAN or a wide area network (WAN)))) to communicate with an external electronic device. These various types of communication modules may be implemented as a single component (e.g., a single IC), or may be implemented as multiple components separated from each other (e.g., multiple ICs). The wireless communication module 1192 may identify and authenticate the electronic device 1101 in a communication network (such as the first network 1198 or the second network 1199) using user information (e.g., an International Mobile Subscriber Identity (IMSI)) stored in the user identification module 1196.

[0168] The antenna module 1197 may transmit or receive a signal or power to or from the outside of the electronic device 1101 (e.g., an external electronic device). The antenna module 1197 may include one or more antennas, and at least one antenna suitable for a communication scheme used in a communication network (such as the first network 1198 or the second network 1199) may be selected from the plurality of antennas by, for example, the communication module 1190 (e.g., the wireless communication module 1192). A signal or power may then be transmitted or received between the communication module 1190 and the external electronic device via the selected at least one antenna.

[0169] A command or data may be sent or received between the electronic device 1101 and the external electronic device 1104 via the server 1108 connected to the second network 1199. Each of the electronic device 1102 and the electronic device 1104 may be a device of the same type as the electronic device 1101, or a device of a different type from the electronic device 1101. All or some operations to be executed in the electronic device 1101 may be executed in one or more of the external electronic device 1102, the external electronic device 1104, or the server 1108. For example, if the electronic device 1101 should automatically execute a function or service or should execute a function or service in response to a request from a user or another device, the electronic device 1101 may request the one or more external electronic devices to execute at least part of the function or service instead of executing the function or service, or the electronic device 1101 may request the one or more external electronic devices to execute at least part of the function or service in addition to executing the function or service. The one or more external electronic devices that receive the request may execute the requested at least part of the function or service, or execute another function or another service related to the request, and transmit the result of the execution to the electronic device 1101. The electronic device 1101 may provide the result as at least a partial reply to the request with or without further processing the result. To this end, for example, cloud computing technology, distributed computing technology, or client-server computing technology may be used.

[0170] Fig.12 A system is shown including a UE 1205 and a gNB 1210 communicating with each other.

[0171] refer to Fig.12 , the UE may include a radio 1215 and a processing circuit (or means for processing) 1220, which may perform various methods disclosed herein, such as Fig.10 For example, processing circuit 1220 may receive a transmission from network node (gNB) 1210 via radio 1215, and processing circuit 1220 may send a signal to gNB 1210 via radio 1215.

[0172] The subject matter and the embodiments of the operation described in this specification may be implemented in digital electronic circuits, or in computer software, firmware or hardware (including the structures disclosed in this specification and their structural equivalents, or a combination of one or more of them). The embodiments of the subject matter described in this specification may be implemented as one or more computer programs encoded on a computer storage medium for execution or control of the operation of a data processing device, that is, one or more modules of computer program instructions. Alternatively or additionally, the program instructions may be encoded on an artificially generated propagation signal (e.g., a machine-generated electrical, optical or electromagnetic signal), which is generated to encode information to be sent to a suitable receiver device for execution by a data processing device. The computer storage medium may be in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof, or the computer storage medium may be included in a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination thereof. In addition, although the computer storage medium is not a propagation signal, the computer storage medium may be the source or destination of the computer program instructions encoded in the artificially generated propagation signal. The computer storage medium may also be one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices), or the computer storage medium may be included in one or more separate physical components or media (e.g., multiple CDs, disks, or other storage devices). In addition, the operations described in this specification may be implemented as operations performed by a data processing device on data stored on one or more computer-readable storage devices or received from other sources.

[0173] Although this specification may contain many specific implementation details, the implementation details should not be interpreted as limiting the scope of any claimed subject matter, but rather as a description of features specific to a particular embodiment. Specific features described in the context of a separate embodiment in this specification may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination. In addition, although the features may be described above as functioning in a particular combination and even initially claimed as such, one or more features from the claimed combination may be deleted from the combination in some cases, and the claimed combination may be directed to a sub-combination or a variation of the sub-combination.

[0174] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order, or that all of the operations shown be performed, to achieve the desired results. In certain circumstances, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the above-described embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0175] Thus, particular embodiments of the subject matter have been described herein. Other embodiments are within the scope of the appended claims. In some cases, the actions set forth in the claims can be performed in a different order and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve the desired results. In particular embodiments, multitasking and parallel processing may be advantageous.

[0176] As those skilled in the art will recognize, the innovative concepts described herein are susceptible to modification and variation in a wide range of applications. Therefore, the scope of the claimed subject matter should not be limited to any specific exemplary teachings discussed above, but rather is defined by the appended claims.

Claims

1. A method performed by a user equipment UE in a non-terrestrial network NTN, the method comprising: Receiving a positioning reference signal PRS from a base station in a downlink DL subframe; Determine a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of a UE uplink (UL) subframe that is closest in time to the DL subframe; Determine a UE time difference from receiving the PRS to sending a sounding reference signal SRS based on a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of the UE UL subframe; generating an assistance report, the assistance report comprising adjustment information for a location management function LMF to calculate the UE time difference; providing said auxiliary report to said LMF; as well as The SRS is reported to the LMF based on the UE time difference.

2. The method according to claim 1, wherein: The adjustment information includes a Doppler frequency measured when receiving the PRS and a Doppler frequency measured when transmitting the SRS.

3. The method according to claim 1, wherein: The adjustment information includes a difference value of a Doppler frequency, wherein the difference value of the Doppler frequency is based on a difference between a Doppler frequency measured when the PRS is received and a Doppler frequency measured when the SRS is transmitted.

4. The method according to claim 1, wherein: The adjustment information includes a difference value of a Doppler frequency, wherein the difference value of the Doppler frequency is based on a difference between a Doppler frequency measured at a time point before receiving the PRS and a Doppler frequency measured when the SRS is transmitted.

5. The method according to claim 1, wherein: The adjustment information includes a Doppler frequency measured at a time point before receiving the PRS and a Doppler frequency measured when transmitting the SRS.

6. The method according to claim 1, wherein: The adjustment information includes a total value of a timing advance (TA) adjustment applied by the UE from a time point before receiving the PRS to a time point when the SRS is sent.

7. The method according to claim 1, wherein: The adjustment information includes a total value of a timing advance (TA) adjustment applied by the UE from a time point of receiving the PRS to a time point of sending the SRS.

8. The method according to claim 6 or 7, wherein: The total value of the TA adjustment includes autonomous adjustment or network-triggered adjustment.

9. The method according to claim 1, further comprising: Report the UE time difference to the LMF.

10. The method according to claim 9, further comprising: Report to the LMF at least one of the following: the subframe index of the UE UL subframe that is closest in time to the DL subframe and the subframe index of the subframe in which the UE transmits the SRS, or An offset value indicating a time offset between a UE transmission timing of a UL subframe of the UE that is temporally closest to the DL subframe and a UE transmission timing of a subframe in which the UE transmits the SRS.

11. The method according to claim 1, wherein: The step of providing the auxiliary report to the LMF comprises one of the following: Provides separate assistance reports for each SRS transmission; providing a selective assistance report for one SRS, the selective assistance report being valid for all individual SRS transmissions; or An average assistance report is provided, the average assistance report including an average of the adjustment information for all SRS transmissions.

12. A user equipment UE used in a non-terrestrial network NTN, the UE comprising: at least one processor; as well as A memory storing instructions, wherein when the instructions are executed by the at least one processor, the UE is controlled to perform the following operations: receiving a positioning reference signal PRS from a base station in a downlink DL subframe, determining a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of a UE uplink (UL) subframe that is closest in time to the DL subframe, determining a UE time difference from receiving the PRS to sending a reference signal SRS based on a timestamp or subframe index of the PRS in the DL subframe and a timestamp or subframe index of the UE UL subframe, generating an assistance report, the assistance report comprising adjustment information for a location management function LMF to calculate the UE time difference, providing said assistance report to said LMF, and The SRS is reported to the LMF based on the UE time difference.

13. The UE according to claim 12, wherein: The adjustment information includes a Doppler frequency measured when receiving the PRS and a Doppler frequency measured when transmitting the SRS.

14. The UE according to claim 12, wherein: The adjustment information includes a difference value of a Doppler frequency based on a difference between a Doppler frequency measured when the PRS is received and a Doppler frequency measured when the SRS is transmitted.

15. The UE according to claim 12, wherein: The adjustment information includes a difference value of a Doppler frequency based on a difference between a Doppler frequency measured at a time point before receiving the PRS and a Doppler frequency measured when the SRS is transmitted.

16. The UE according to claim 12, wherein: The adjustment information includes a Doppler frequency measured at a time point before receiving the PRS and a Doppler frequency measured when transmitting the SRS.

17. The UE according to claim 12, wherein: The adjustment information includes a total value of a timing advance (TA) adjustment applied by the UE from a time point before receiving the PRS to a time point when the SRS is sent.

18. The UE according to claim 12, wherein: The adjustment information includes a total value of a timing advance (TA) adjustment applied by the UE from a time point of receiving the PRS to a time point of sending the SRS.

19. The UE according to claim 17 or 18, wherein: The total value of the TA adjustment includes autonomous adjustment or network-triggered adjustment.

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