Positioning a ue using multiple over-the-air communication systems

Abstract

A method for locating a UE. The method is performed by a first air communication system (ACS). The method includes obtaining information indicating the duration of a time window (TWD) for the first ACS, wherein the TWD for the first ACS is determined based on timing information for the first ACS and timing information for a second ACS (1402). The method further includes performing a positioning measurement procedure within the first window period based on the indicated TWD.

Description

Technical Field

[0001] Embodiments relating to the use of two or more airborne communication systems (ACS) (e.g., two or more satellites) to locate the UE are disclosed. Background Technology

[0002] Non-terrestrial networks (NTN) Satellite communications are experiencing a resurgence. Several initiatives for NTN (also known as satellite networks) have been announced in the past few years. NTN complements terrestrial mobile networks by providing connectivity and multicast / broadcast services to underserved areas.

[0003] To benefit from a robust mobile ecosystem and economies of scale, there is significant interest in adapting terrestrial radio access technologies, including Long Term Evolution (LTE) and New Radio (NR), to NTN, as reflected in the 3GPP standardization work.

[0004] NTN typically includes: an airborne communication system (ACS), which includes an airborne vehicle (AV) with communication capabilities (i.e., one or more AVs), such as a satellite in orbit, an unmanned airborne vehicle (UAV), or other airborne vehicles; one or more gateways (GWs) (e.g., earth-based GWs) that communicatively connect the ACS to the core network or base stations (depending on the architecture choice); feeder links (i.e., links between GWs and AVs); and access links (also known as service links) (i.e., links between AVs and user equipment (UEs)).

[0005] Geostationary orbit (GEO) satellites are fed by one or more GWs deployed across satellite target coverage (e.g., regional or even continental coverage). Non-GEO satellites are successively served by several GWs as the satellite moves relative to the Earth. The system ensures service and feeder link continuity between successively serving GWs, and provides sufficient duration for mobility anchoring and handover.

[0006] An ACS can provide either a transparent payload or a regenerated payload (using onboard processing). An ACS typically generates several beams over a given service area defined by its field of view. The coverage area of ​​the beams is usually elliptical. The field of view of an ACS depends on the onboard antenna pattern and the minimum elevation angle.

[0007] When the ACS achieves a transparent payload, the AV of the ACS can perform radio frequency (RF) filtering, conversion, and / or amplification. Therefore, the waveform signal remains unchanged, and the AV is referred to as "transparent" AV.

[0008] When the ACS implements regenerated payload, the AV of the ACS can perform not only RF filtering, frequency conversion, and amplification, but also demodulation, decoding, switching, routing, encoding, and / or modulation. This is practically equivalent to having an onboard base station on the AV (e.g., a 3GPP 5G base station (also known as a gNB)).

[0009] In scenarios where the NTN includes an AV (e.g., satellite) constellation, the NTN can employ inter-satellite links (ISLs) (e.g., links between adjacent AVs). This will require regenerative payloads on the AV boards. ISLs can operate in RF frequencies or optical bands.

[0010] The table below identifies the different AV types and their typical characteristics.

[0011] Table 1 Figure 1-4 Different example NTN architectures are shown. Figure 1 This illustrates a networked RAN architecture with transparent satellites. Figure 2 This shows regenerated satellites without ISL and payloads processed by gNB. Figure 3 The image shows a regenerated satellite with ISL and a payload processed by gNB. Figure 4 This illustrates a next-generation (NG) radio access network (RAN) with NB-DU-based regenerative satellites.

[0012] In addition to the scenarios mentioned above, multi-connectivity scenarios are also discussed, where NG-RAN based on, transparent or regenerated NTN is combined with terrestrial NG-RAN (NR or EUTRA) or another NTN. Therefore, a UE can be simultaneously connected and served by at least the following: an NTN-based NG-RAN and a terrestrial access (NR or EUTRA), or an NTN-based NG-RAN and another NTN-based NG-RAN.

[0013] NTN can have beam-based coverage, for example, Figure 5 As shown in the image. Figure 5 This illustrates a typical NTN scenario with beam-based coverage based on regenerated payload. In the 3GPP Release 17 work project for NR NTN, only the transparent payload architecture was considered.

[0014] Figure 6 An example architecture (i.e., a transparent payload architecture) of a satellite network with a bend transponder is shown. The base station (BS) can be integrated into the GW or connected to the GW via terrestrial connections (wired, fiber, or wireless links).

[0015] The defining characteristic of ACS is that its path loss is significantly higher than that expected in terrestrial networks. To overcome this path loss, access links and feeder links are typically required to operate under line-of-sight conditions, and the UE is equipped with an antenna that provides high beam directivity.

[0016] ACS typically generates several beams over a given area. The coverage area of ​​the beams is usually elliptical and has traditionally been considered a cell (but this does not exclude cells composed of multiple beams). The coverage area of ​​the beams is also often referred to as a spot beam. A spot beam can move across the Earth's surface with the movement of the AV (and the Earth's rotation), or it can be fixed relative to the Earth using some beam pointing mechanism used by the AV to compensate for its motion. The size of the spot beam depends on the system design, and its range can range from tens of kilometers to thousands of kilometers.

[0017] Compared to beams observed in terrestrial networks, NTN beams offer very wide coverage, extending beyond the area defined by the served cell. Beams covering adjacent cells will overlap, leading to significant inter-cell interference levels due to a slow decrease in signal strength in the outward radial direction. This is partly attributed to the high elevation angle and long distances to the network-side transceivers, resulting in a relatively small difference between the distance from the cell center to the AV and the distance from a point at the cell edge to the AV compared to terrestrial cells. To overcome these large interference levels, a typical approach in NTNs is to configure different cells using different carrier frequencies and polarization patterns.

[0018] The NTN supports three types of beams or cells: (1) Earth-fixed beams / cells: provided by one or more beams that continuously cover the same geographic area (e.g., in the case of GEO satellites); (2) Quasi-Earth-fixed beams / cells: provided by one or more beams that cover one geographic area for a limited time period and a different geographic area for another time period (e.g., in the case of NGSO satellites that generate steerable beams); and (3) Earth-moving beams / cells: provided by one or more beams whose coverage area slides across the surface of the Earth (e.g., in the case of NGSO satellites that generate fixed or non-steerable beams). Unless otherwise expressly stated, the terms beam and cell are used interchangeably throughout this disclosure.

[0019] Of the three cell types mentioned above, quasi-fixed cells and mobile cells appear to be the most promising for practical deployment. In the case of a mobile cell, each cell (the coverage area of ​​its(one) or more beams) moves across the Earth's surface as its serving satellite moves along its orbit. In the case of a quasi-fixed cell, the cell area (as the name suggests) remains fixed in the same geographical area, independent of satellite movement. To achieve this, the serving satellite must have a means of dynamically guiding its(one) or more beams so that it still covers the same area of ​​the Earth despite satellite movement. However, because satellites orbit the Earth, unless the satellite is in geostationary orbit (and note that LEO satellites are the most popular in the satellite communications industry), the same satellite will only cover the same area of ​​the Earth for a limited time.

[0020] This means that different satellites will be assigned the task of covering a specific geographic area at different times. When this task switches from one satellite to another, it essentially means that one cell is replaced by another, even though they cover the same area. A similar cell replacement occurs when a satellite covering a geographic area switches its feeder link (because it has moved away from its old GW / gNB and is closer to another GW / gNB). As a result, all UEs connected in the old cell (i.e., UEs in the RRC_CONNECTED state) must be handed over from the old cell (or moved in other ways, such as using RRC connection reconstruction) to the new cell, and all UEs camped on the old cell (i.e., UEs in the RRC_IDLE or RRC_INACTIVE state) must perform cell reselection to the new cell.

[0021] For this type of cell handover, there are two alternative principles: hard handover and soft handover. Hard handover involves an instantaneous handover from the old cell to the new cell (i.e., the new cell appears and the old cell disappears simultaneously). This makes a completely seamless (i.e., uninterrupted) handover practically impossible, and the potential surge in access attempts when many UEs immediately attempt to access the new cell after the handover can overload access resources in the new cell. Soft handover involves a period during which the new and old cells coexist (i.e., overlap), covering the same geographical area. This coexistence / overlap period allows connected UEs time to handover and allows camped UEs to reselect to the new cell, which helps distribute access load in the new cell, thus providing better conditions for handover with shorter downtime. Soft handover is likely the most common cell handover principle in quasi-earth fixed-cell deployments.

[0022] The time when a pseudo-earth fixed cell will cease service in the current area (i.e., the time when a pseudo-earth fixed cell will cease to exist) is indicated by the t-Service-r17 information element (IE), which is broadcast in System Information Block 19 (SIB19) in NR NTN (and in SIB31 in IoT NTN).

[0023] Location-Architecture in NR Since 3GPP Release 9, location (i.e., determining the location of the UE) has been a central theme in LTE standardization. The primary goal of location in LTE is to meet regulatory requirements for emergency call location, with a target of achieving a horizontal accuracy of <50m.

[0024] Starting with Release 15 (Rel-15) of the specification, positioning is also supported in NR. Positioning in NR is... Figure 7 The architecture shown in the diagram supports 3GPP TS 38.305 V17.5.0 (“TS 38.305”). Figure 5 The interaction between the gNodeB and the UE is supported by the Radio Resource Control (RRC) protocol, while the location node interfaces with the UE via the LTE Positioning Protocol (LPP). LPP is a protocol shared by both NR and LTE. There is also interaction between the location node and the gNodeB via the NRPPa protocol.

[0025] Location in NR - Location process As described in Section 5.2 of TS 38.305 V17.5.0, the entire sequence of events applicable to the UE, NG-RAN, and Location Management Function (LMF) for any location service is shown in Figure 8 In the image, the figure is for TS 38.305. Figure 5 .2-1 copy.

[0026] Note that when the AMF receives a location service request while the UE is in CM-IDLE state, the AMF executes a network-triggered service request to establish a signaling connection with the UE and assign a specific serving gNB or ng-eNB. Assume the UE is in... Figure 8 The process shown begins in connected mode, meaning that any signaling that might be required to bring the UE into connected mode before step 1a is not shown. However, the signaling connection may be released later while positioning is still in progress (e.g., by the NG-RAN node as a result of signaling and data inactivity).

[0027] The following description Figure 8 The sequence of events shown in the figure.

[0028] An entity in the 5GC (e.g., GMLC) requests a location service (e.g., location) for the target UE from the serving AMF (step 1a), or the serving AMF of the target UE determines that a location service is needed (e.g., to locate the UE for an emergency call) (step 1b), or the UE requests a location service (e.g., location or assisted data transfer) from the serving AMF at the NAS level (step 1c).

[0029] 2. AMF forwards the location service request to LMF.

[0030] 3a. The LMF initiates a location procedure with the ng-RAN serving and potentially neighboring ng-eNB or gNB—for example, to obtain location measurements or auxiliary data.

[0031] 3b. In addition to or instead of step 3a, the LMF initiates a location procedure with the UE—for example, to obtain a location estimate or positioning measurement, or to transmit location assistance data to the UE.

[0032] 4. The LMF provides the AMF with a location service response, including any desired results—for example, a success or failure indication, and, if requested and obtained, a location estimate of the UE.

[0033] 5a. If step 1a was performed, the AMF returns a location service response to the 5GC entity in step 1a, including any desired results such as the UE's location estimate.

[0034] 5b. If step 1b occurs, the AMF uses the location service response received in step 4 to assist the service that triggered this in step 1b (e.g., providing the GMLC with a location estimate associated with the emergency call).

[0035] 5c. If step 1c was performed, the AMF returns a location service response to the UE, including any desired results such as the UE's location estimate.

[0036] The location process applicable to NG-RAN occurs Figure 8 Steps 3a and 3b are described in more detail in this specification. Figure 8 The other steps in this process only apply to 5GC.

[0037] Steps 3a and 3b may involve using different positioning methods to obtain location-related measurements for the target UE, and thereby calculating a location estimate and any additional information (such as velocity).

[0038] Location methods relying on Radio Access Technology (RAT) The positioning methods supported by LTE include: enhanced cell ID; assisted GNSS; Time Difference of Observation Arrival (OTDOA); and uplink TDOA (UTDOA), which are described below.

[0039] Enhanced Cell ID: The cell ID information is used to associate the UE with the service area of ​​the serving cell, and then additional information is used to determine the UE's location with finer granularity.

[0040] Auxiliary GNSS: GNSS information retrieved by the device, supported by auxiliary information provided to the device from the E-SMLC.

[0041] Observed Time Difference of Arrival (TDOA): The UE performs positioning measurements (in this case, Reference Signal Time Difference (RSTD) measurements) on the downlink (DL) positioning reference signals (DL-PRS) transmitted by the base station (BS) and reports them to the E-SMLC for location estimation.

[0042] Uplink (UL) TDOA (UTDOA): Similar to Observation TDOA (OTDOA), but in the uplink direction. The network node performs positioning measurements on the reference signal transmitted by the UE for positioning measurements in the UL. The measurements are reported to the E-SMLC, where final position estimation is performed.

[0043] NR-supported positioning methods Compared to LTE, NR positioning benefits from greater bandwidth and finer beamforming, and can locate user equipment (UE) with higher accuracy. It also supports the following positioning methods: DL-TDOA, multiple round-trip time (RTT), UL-TDOA, DL departure angle (DL-AoD), UL arrival angle (UL-AoA), and NR enhanced cell ID (NR E-CID).

[0044] The DL TDOA positioning method utilizes the downlink reference signal time difference (DL RSTD) measurement performed by the UE on positioning reference signals (PRS) transmitted by multiple transmit and receive points (TRPs). This method is similar to OTDOA in LTE.

[0045] The multi-RTT positioning method utilizes multiple round-trip time (RTT) measurements to estimate the UE location. For each RTT measurement, the time difference between the UE Rx-Tx and gNB Rx-Tx is used.

[0046] The UL TDOA positioning method utilizes the UL TDOA (and optional UL SRS-RSRP) of the uplink signal transmitted from the UE at multiple TRPs. The RP uses auxiliary data received from the positioning server to measure the UL TDOA (and optional UL SRS-RSRP) of the received signal and uses the obtained measurements with other configuration information to estimate the UE's location.

[0047] The DL AoD positioning method utilizes the DL PRSRSRP measured at the UE from downlink signals received from multiple TRPs. The UE uses auxiliary data received from the positioning server to measure the DL PRSRSRP of the received signals and uses the obtained measurement together with other configuration information to locate the UE.

[0048] The UL AoA positioning method utilizes the azimuth and zenith angles of arrival (AOA) measured at multiple TRPs on the uplink signal transmitted from the UE. The TRPs use auxiliary data received from the positioning server to measure the A-AoA and Z-AoA of the received signal and use the obtained measurements along with other configuration information to estimate the UE's position.

[0049] NR-ECID positioning refers to a technique that uses additional UE measurements and / or NR radio resources and other measurements to improve UE location estimation.

[0050] NR positioning modes can be categorized as UE-assisted, UE-based, or standalone. In the UE-assisted category, the UE performs measurements with or without network assistance and sends these measurements to the E-SMLC, where location calculation is performed. In the UE-based category, the UE performs measurements and calculates its own location with network assistance. In the standalone category, the UE performs measurements and calculates its own location without network assistance.

[0051] Multi-RTT positioning Multi-RTT positioning is introduced to determine the RTT from downlink and uplink measurements for positioning purposes. Since 3GPP Release 16, NR provides DL-PRS and UL-SRS signals. The DL-PRS signal is a sequence-modified and interleaved comb-shaped QPSK signal carrying a PN sequence, while the UL-SRS signal is a regular comb-shaped signal carrying a Zadoff-Chu sequence. Both types of signals can be correlated with corresponding replica signals at their respective endpoints. The time instances of correlation peaks allow for the determination of the delay between the transmitter and receiver.

[0052] exist Figure 9 and Figure 10The diagram illustrates a multi-RTT positioning method. First, for each gNB and UE pair, the RTT is calculated based on (gNB_Rx - gNB_Tx) - (UE_Rx - UE_Tx). After determining the RTT for all gNB and UE pairs, assuming the gNB locations are known, the LMF should be able to estimate the distance between the UE and each gNB, and thus estimate the UE location.

[0053] For UE location verification based on multiple RTTs in an NTN involving LMF, the detailed process can be as follows: First, the network should configure location resources. Compared to traditional multi-RTT positioning, the network can also configure the period for RTT measurements. After triggering a measurement, the UE and network node periodically measure the DL-PRS and transmit one or more UL-SRS resources according to the configured location resources. Then, the network node and / or UE can report the Rx-Tx time difference once after each measurement or after all measurements. After the measurement, the LMF determines the RTT and calculates the UE location.

[0054] exist Figure 11 The diagram illustrates the timing sequence used to measure RTT. In each RTT measurement, after the LMF operation, in the downlink, the gNB should transmit the PRS at td0, the satellite receives the PRS at td1 and transmits it to the UE, and the UE receives the PRS at td2 and begins measuring the PRS. Similarly, the UE transmits the Sound Reference Signal (SRS) at tu0, the satellite node receives the SRS at tu1 and transmits it to the gNB, and the gNB receives the SRS at tu2 and begins measuring the SRS.

[0055] Therefore, the RTT determined at or after tu2 is the RTT from the gNB's perspective = (tu2 - td0) - (tu0 - td2), while the actual RTT from the satellite's perspective = (tu1 - td1) - (tu0 - td2), the latter being used for UE positioning. It is worth noting that... Figure 11 The timing sequence described is one of the definitions of RTT. There may be other definitions of RTT, but the basic principle of RTT is the same and can also be applied to this invention.

[0056] Within a complete multi-RTT measurement, the above time series should be repeated, denoted by at least T1, T2, and T3, for example, at the start or end, or trigger or initiate at least Figure 12The terms T1, T2, and T3 are shown in the diagram. T1 indicates when the first RTT measurement begins or ends, or is triggered or initiated; T2 indicates when the second RTT measurement begins or ends, or is triggered or initiated; and so on. In one example, depending on the viewpoint, T1 is equal to td0, td1, td2, tu0, tu1, or tu2. Time series of T1, T2, and T3 are frequently used, although more appropriate terms would be location measurement sequence, set of location measurements, location measurement set, repeated location measurements, etc.

[0057] To estimate the UE location using RTT measurements, it is important to know at least the location of the TRP / satellite node transmitting (one or more) PRS resources, upon which the UE performs UE Rx-Tx time difference measurements, i.e., tu2 and td0 in the RTT equation above. For this purpose, in NR multi-RTT positioning where the TRP is deployed at a fixed location, providing a unique DL-PRS ID for the TRP in the auxiliary data is sufficient, as currently supported by the NR positioning specification for multi-RTT positioning methods. However, in the context of NTN, where a single satellite node is to be used for UE location estimation, due to the mobile nature of satellite nodes, the LMF needs to provide a time instance in which the UE should perform Rx-Tx time difference measurements. The LMF can also provide similar auxiliary data to the satellite node to help it perform meaningful Rx-Tx time difference measurements for UE location estimation. Therefore, due to the mobile nature of the satellite nodes transmitting (one or more) PRS resources, converting RTT to distance / range from the satellite perspective for location estimation should be done as follows: .

[0058] For this equation to work, the auxiliary data given to the UE should include, for example, td1 as a time instance at which it should perform positioning measurements on one or more DL PRS resources transmitted by the satellite node. The auxiliary data given to the UE should also include, for example, tu0 as a time instance to configure the UE to begin transmitting one or more SRS resources for positioning measurements. It should also be noted that the variable Pue in the above equation represents the location of the target UE estimated using multiple RTT measurements.

[0059] Existing NR positioning specifications support multi-RTT-based positioning for cellular networks, where the TRP (Target Positioning Point) is located at a static, fixed location that does not change over time. In NTN networks, the positioning process for an NTN UE may involve one or more satellites. If the positioning process involves only a single satellite, it is expected that the UE performs RTT measurements at different locations with the same satellite (e.g., ...). Figure 13(As shown in the diagram). The network should use multiple such measurements to estimate the UE's location on Earth. Compared to traditional solutions where the LMF provides auxiliary data for positioning measurements to the UE based on a static TRP location, for NTN, the auxiliary data should consider the moving TRP, where multiple RTT measurements are performed on PRS transmitted from different locations by the same satellite at different times. To locate the target UE, multiple measurement times are combined to mimic different TRPs. At each measurement time, both the UE and the satellite (gNB) need to provide an RX-TX difference report.

[0060] Furthermore, when it is necessary to locate the UE, it is also feasible to have those multiple satellites participate in the location of the UE if multiple satellites are available.

[0061] Scheduling and timing As described in Clause 16.14.2.1 of TS 38.300 v17.5.0 (“TS 38.300”), in order to accommodate the propagation delay in NTN, by Figure 13 The diagram (showing the timing relationship) illustrates the common timing advance (common TA) and the two scheduling offsets. K offset and k mac To enhance several timing relationships.

[0062] The common TA is the configured offset, which corresponds to the RTT between the reference point (RP) and the NTN payload.

[0063] K offset It is the configured scheduling offset, which must be greater than or equal to the sum of the service link RTT and the common TA.

[0064] K mac It is the configured offset, which needs to be greater than or equal to the RTT between RP and gNB.

[0065] DL and UL are frame-aligned at the uplink time synchronization reference point (RP), with their offset determined by N. TA,offset Provided (see Clause 4.3 of TS38.211 v17.5.0 (“TS 38.211”).

[0066] Offset k mac Used for delaying the application of downlink configuration indicated by the MAC CE command on the PDSCH, and for estimating UE-gNB RTT. When downlink and uplink frame timings are misaligned at the gNB, this can be provided by the network. k mac . k macIt is also used in random access procedures to determine the start time of the RAR window / MsgB window after Msg1 / MsgA transmission. Summary of the Invention

[0067] Existing NR positioning specifications support positioning for terrestrial cellular networks, where the TRP (Terrestrial Point of Reach) is located at a static, fixed location that does not change over time. In NTN networks, positioning processes involving multiple ACS (e.g., multiple satellites) (including the serving cell / satellite and one or more neighboring cells / satellites) can provide more accurate, robust, and faster positioning results compared to positioning processes based on a single ACS (e.g., the serving cell / satellite), but they may encounter more complex conditions between different satellites (e.g., between the serving satellite and one or more neighboring cells / satellites). Therefore, in 3GPP Rel-18, positioning involving multiple satellites was given lower priority.

[0068] Several challenges exist. For example, one of the complexities is handling the timing differences between multiple ACSs, where the timing difference can be several microseconds. For a UE participating in a positioning process with multiple ACSs, the UE will have different propagation delays to each ACS (e.g., different propagation delays to the AVs of each ACS). With each AV moving at the same or different speeds, the position of each AV is not static during the positioning process, making it impractical to directly reuse existing Uu positioning procedures (e.g., multiple RTTs) to position the UE in the NTN network. In other words, for each UL transmission timing, after the UE has transmitted the UL positioning reference signal (e.g., SRS), some selected ACSs may fail to receive the UL signal due to a large timing difference compared to other ACSs, thus failing to obtain a measurement of the UL reference signal (RS). This can happen because the UE may reference the timing of the serving ACS to perform the UL RS transmission. Therefore, it is necessary to develop solutions to handle the timing differences between ACSs in multi-ACS positioning scenarios.

[0069] Therefore, in one aspect, a method for locating a UE is provided. The method is performed by a first air communication system (ACS). The method includes obtaining information indicating the duration (TWD) of a time window for the first ACS, wherein the TWD for the first ACS is determined based on timing information for the first ACS and timing information for a second ACS (1402). The method also includes performing a positioning measurement procedure within the first window period based on the indicated TWD.

[0070] In another aspect, a computer program including instructions is provided that, when executed by the processing circuitry of an ACS, cause the ACS to perform any of the methods disclosed herein. In one embodiment, a carrier containing a computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium. In another aspect, an ACS configured to perform the ACS methods disclosed herein is provided. The ACS may include memory and processing circuitry coupled to the memory.

[0071] In another aspect, a method performed by a UE is provided. The method includes receiving reference signal configuration information indicating reference signal resources. The method further includes obtaining first timing information for a first ACS. The method further includes obtaining second timing information for a second ACS. The method further includes providing the first and second timing information to a location server, the first ACS, and / or the second ACS. The method further includes transmitting a reference signal using the indicated reference signal resources after providing the timing information.

[0072] In another aspect, a computer program including instructions is provided, which, when executed by the processing circuitry of a UE, cause the UE to perform any of the UE methods disclosed herein. In one embodiment, a carrier containing a computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium. In another aspect, a UE configured to perform the UE methods disclosed herein is provided. The UE may include memory and processing circuitry coupled to the memory.

[0073] In another aspect, a method performed by a location server is provided. The method includes receiving a location service request relating to a UE, wherein the UE is being served by a serving ACS. The method further includes determining whether a first non-serving ACS should be configured to perform location measurements at least with respect to a first reference signal to be transmitted by the UE. This determination is based on first timing information indicating a propagation delay between the UE and the serving ACS and second timing information indicating a propagation delay between the UE and the first non-serving ACS.

[0074] In another aspect, a computer program including instructions is provided that, when executed by processing circuitry of a location server, cause the location server to perform any of the methods disclosed herein. In one embodiment, a carrier containing a computer program is provided, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium. In another aspect, a location server configured to perform the location server methods disclosed herein is provided. The location server may include memory and processing circuitry coupled to the memory.

[0075] The advantages of the embodiments disclosed herein are that they provide a solution for handling timing differences between ACSs when positioning a UE using multiple ACSs. ​​For example, even though there are large timing differences between satellites, each ACS involved in the positioning process can efficiently obtain the required positioning measurements, thereby improving positioning accuracy when multiple satellites are involved in the positioning process. Attached Figure Description

[0076] Various embodiments are illustrated in the accompanying drawings, which are incorporated herein and form part of the specification.

[0077] Figure 1 This illustrates a networked RAN architecture with transparent satellites.

[0078] Figure 2 This shows regenerated satellites without ISL and payloads processed by gNB.

[0079] Figure 3 The image shows a regenerated satellite with ISL and a payload processed by gNB.

[0080] Figure 4 This illustrates a next-generation (NG) radio access network (RAN) with NB-DU-based regenerative satellites.

[0081] Figure 5 This illustrates a typical NTN scenario based on regenerated net load.

[0082] Figure 6 An example architecture of a satellite network with a bend transponder is shown.

[0083] Figure 7 The overall architecture for UE positioning is shown for NG-RAN.

[0084] Figure 8 This shows location service support provided by NG-RAN.

[0085] Figure 9 This illustrates a multi-RTT positioning method.

[0086] Figure 10 This illustrates a multi-RTT positioning method.

[0087] Figure 11 The timing sequence used to measure RTT is shown.

[0088] Figure 12 This shows a repeating time series.

[0089] Figure 13 Provide a diagram illustrating the timing relationship.

[0090] Figure 14 A system according to an embodiment is shown.

[0091] Figure 15 This is a signaling diagram illustrating a process according to an embodiment.

[0092] Figure 16 This is a flowchart illustrating a process according to an embodiment.

[0093] Figure 17 This is a flowchart illustrating a process according to an embodiment.

[0094] Figure 18 This is a flowchart illustrating a process according to an embodiment.

[0095] Figure 19 This is a block diagram of the UE according to an embodiment.

[0096] Figure 20 This is a block diagram of the UE according to an embodiment.

[0097] Figure 21 This is a block diagram of a base station according to an embodiment. Detailed Implementation

[0098] Figure 14 A system 1400 according to an embodiment is shown. System 1400 includes a plurality of ACSs (represented by ACS 1401 and ACS 1402) and a UE 1421 to be located. Figure 14 As shown, each ACS includes an AV containing at least one TRP. Specifically, ACS 1401 includes AV 1441 containing TRP 1411 (e.g., an antenna system, base station, or other TRP), and ACS 1402 includes AV 1442 containing TRP 1412. ACS 1401 also includes a GW 1434 containing TRP 1436, and ACS 1402 also includes a GW 1424 containing TRP 1436. System 1400 also includes a core network 1428 containing a location server (LS) 1430 (e.g., LMF). Depending on the architecture of ACS 1401, TRP 1411 may function as a base station (regenerative architecture), or TRP 1411 may simply act as a repeater or relay (transparent architecture). Similarly, TRP 1412 may function as a base station (regenerative architecture), or TRP 1412 may simply act as a repeater or relay (transparent architecture). As used herein, the term “base station” is used broadly such that, at least in some embodiments, it means one or more control units (CUs) of a base station (e.g., one or more CUs of a gNB) and / or one or more distributed units (DUs) of a base station (e.g., one or more DUs of a gNB).

[0099] This disclosure describes embodiments for handling timing differences between ACSs (e.g., between TRP 1411 of AV 1441 and TRP 1412 of AV 1442) during the positioning process of UE 1421. In one embodiment, for each ACS participating in the positioning process, time window information indicating a window period is provided to the ACS (e.g., provided to the TRP on the ground or the TRP on the AV board of the ACS), and each ACS attempts to obtain positioning measurements within the window period defined by the time window information received by the ACS. Alternatively, the UE may transmit separate UL Positioning Reference Signals (PRS) (e.g., SRS) to each different ACS. The advantage of these embodiments is that, although there are large timing differences between ACSs, each ACS can efficiently obtain the required positioning measurements; thereby improving positioning accuracy involving multiple ACSs.

[0100] Alternative Option 1 - Apply the same UL reference signal (also known as the measurement signal). This embodiment describes a method for handling timing differences when using the same UL positioning RS.

[0101] In the location procedure (also known as the location session) used to locate UE 1421, multiple ACSs (e.g., ACS 1401 and ACS 1402) can be used to determine the UE's location. The UE performs UL transmissions to the ACS using the same resources (e.g., the same SRS and the same time resources). The ACS performs measurements on the UL transmissions from the UE. As used herein, "time resources" can be any type of physical or radio resource expressed in terms of time length. Examples of time resources are: symbols, time slots, subframes, radio frames, transmission time intervals (TTI), interleaving times, time slots, sub-time slots, mini-time slots, etc.

[0102] For ACS to obtain UL positioning measurements, the following options are possible.

[0103] Configure a time window for each ACS. Each ACS performs UL measurements within its window. A time window of sufficient duration needs to be set to accommodate timing differences between ACSs.

[0104] In one embodiment, within each window, the UE is required to perform at least one transmission using SRS resources. Each satellite is aware of the resource index. The time window configured for each ACS is wide enough to cover the timing of SRS resource transmissions. Information regarding potential beam / spatial relationships used for SRS transmissions is also communicated to each ACS.

[0105] If a serving satellite is included in a positioning session as an ACS, the UE can transmit a UL positioning reference signal (e.g., SRS) to that serving satellite after the UL timing advance (TA). In this case, a time window duration with a small value can be configured for the serving ACS. The estimated receive timing for uplink transmissions by the serving ACS is covered by this time window. Meanwhile, larger time windows can be configured for other non-serving ACSs.

[0106] In the example, the time window duration (TWD) of a non-service ACS (e.g., ACS2) can be set with reference to the service ACS (e.g., ACS1): TWD = ABS(K offset_ACS1 -K offset_ACS2 (Equation 1), where ABS represents absolute value.

[0107] In the example, the equation can be further updated to: TWD = ABS(ACS1 service link RTT - ACS2 service link RTT) (Equation 2).

[0108] In the example, the equation can be further updated to: TWD = ABS(K offset_ACS1 -K offset_ACS2 ) + delta (Equation 3), or TWD = ABS(ACS1 service link RTT - ACS2 service link RTT) + delta (Equation 4).

[0109] The variable delta is added to the equation to allow for additional time margins to be included in the time window to accommodate timing discrepancies that may arise due to changes in UE timing alignment, SRS resource length, etc.

[0110] The units for the duration of the time window and delta can be microseconds, seconds, time slots, subframes, DRX periods, reference signal periodicity, etc.

[0111] As yet another example, the equation can be updated to: TWD = ABS(RTT of service link and feeder link of ACS1 - RTT of service link and feeder link of ACS2) (Equation 5). In this equation, K for each ACS will be considered. offset K mac The value is used as input to derive the appropriate time window for this ACS. That is, as another example, TWD=ABS(K offset_ACS2 +K mac_ACS2 -K offset_ACS1 -K mac_ACS1), and in another example, TWD=ABS(K offset_ACS2 -ACS2 Public TA-K offset_ACS1 +ACS1's public TA).

[0112] A UE can repeat SRS transmissions using the same SRS frequency resources at multiple time points. These time points can be positioned sequentially or discontinuously (e.g., the gap between two consecutive time points). In this case, it is sufficient for each ACS to receive at least one time point within each time window.

[0113] In one embodiment, among the ACSs participating in the positioning process, one ACS may exchange information with another ACS, the information including or identifying the following items: ephemeris data, K... offset K mac The common TA, subframe number (SFN), and / or the time window of the ACS (including the start time and duration of the window).

[0114] In one embodiment, the UE provides each ACS with information indicating the following: one or more indices (or SFNs) of SRS resources that the UE will transmit / is transmitting to the satellite, the timing of the SRS transmission by the UE during the time window, and / or the time window (including the start time and duration of the window). However, in some embodiments, the time window-related configuration is configured by the base station or location server (e.g., LMF).

[0115] Based on the above information, each ACS can calculate the RX-TX time difference. Considering the possible timing when the UE may have transmitted the SRS to the ACS, the satellite can determine the transmission time of the corresponding SRS by the UE. This information can then be further reported by the ACS to the location server.

[0116] In one embodiment, the serving cell provides the UE and / or the location server with a list of indexes of ACSs or cells associated with ACSs to participate in positioning measurements. In this list, all ACSs have the same or similar propagation delay between the ACS and the UE; in other words, the ACSs in the list have the same UL timing configuration (e.g., TA), and the UE can assume that the ACSs in the list are capable of receiving SRS using a common UL timing configuration without providing additional auxiliary information to the ACSs.

[0117] In one embodiment, if the serving cell does not receive explicit instruction, the UE determines satellites with similar or comparable propagation delays (e.g., compared to the serving satellite) based on ephemeris data and the UE's location. Accordingly, the UE sends a satellite index or cell index associated with the satellite to the serving cell and / or location server, which then requests a positioning procedure from those indicated satellites. The indicated satellites further report their timing information to the location server.

[0118] In one embodiment, for each ACS participating in the positioning process, a first time window can be initiated by the ACS upon receiving a positioning request transmitted by the LMF. If the ACS cannot obtain the required positioning measurements within the first time window, a second time window (with the same or different window duration as the first time window) can be initiated after the first time window expires. For each positioning process, the ACS can initiate up to N time windows to perform positioning measurements to achieve the required positioning accuracy, where N can be a configured or pre-configured value.

[0119] Alternative Option 2 - Applying different UL positioning reference signals This embodiment describes how to handle timing differences when different UL positioning reference signals are applied.

[0120] During the positioning process, multiple ACSs are selected. The UE performs UL transmission to the ACS using different positioning reference signals (e.g., SRS). The ACS performs measurements on the UL transmissions.

[0121] In one embodiment, the UE maintains a separate TA value for each satellite. In general, the UE needs to maintain multiple TA values ​​corresponding to different satellites during the positioning process. Furthermore, during the positioning process, the UE reports to the location server the satellite index / cell index associated with the satellite, as well as the associated TA value or the offset of the TA value compared to the serving satellite.

[0122] In one example, a UE can establish multiple radio links toward multiple satellites, where each link is simultaneously toward different satellites, or shares a time pattern. This type of scenario is therefore referred to as a carrier aggregation scenario or a multi-connectivity scenario. The UE is then configured with different SRS resources on each radio link. The UE then performs independent SRS deliveries toward different satellites on each radio link.

[0123] In another example, upon receiving a location request from or transmitting a location request to the location server, the UE performs a TA acquisition procedure toward multiple satellites (e.g., by transmitting one or more PRACH preambles via the UE), which are identified by the UE or LMF as participating in the location measurement. Depending on the UE's capabilities, the acquisition procedure can be performed on a per-satellite or per-group-satellite basis. After receiving the TA values ​​(e.g., via RRC, MAC-CE signaling), the UE subsequently stores the TA values ​​for these satellites and uses them during the positioning process with those neighboring satellites.

[0124] In some cases, the UE may also need to obtain DL synchronization before acquiring UL timing (i.e., TA) from multiple satellites, because the satellites used for positioning may not always be those used for L3 mobility measurements or have valid ephemeris data. The serving cell signals the UE to notify it of the DL synchronization measurement configuration. At the same time, the serving cell should trigger the transmission of reference signals for DL ​​synchronization from neighboring satellites (this may be aperiodic). The UE then detects the reference signals and uses the obtained DL timing reference for the next UL transmission operation.

[0125] Example use cases Figure 15 This is a signaling diagram illustrating a process according to one embodiment.

[0126] The process begins at step s1502, where the AMF 1432 serving UE 1421 determines that a location service is needed for UE 1421. For example, as described in TS 38.305, an entity in network 1428 (e.g., GMLC) may request a location service (e.g., location) for UE 1421 from the AMF, or the AMF 1432 itself may determine that a location service is needed (e.g., locating the UE for an emergency call), or UE 1421 may request a location service (e.g., location or delivery of auxiliary data) from the AMF 1432 at the Non-Access Stratum (NAS) level.

[0127] After AMF 1432 determines that location services are needed for UE 1421, AMF 1432 sends a location service request message m1503 to LS 1430, which receives and processes the message.

[0128] After receiving the location service request message, LS 1430 obtains timing information for ACS 1401 (which in this example is the ACS serving UE 1421) and for one or more ACS adjacent to ACS 1401 (such as, for example, ACS 1402) (step s1504).

[0129] In one example, LS 1430 can obtain timing information from UE 1421 by sending a request message m1506 requesting timing information (or at least a portion thereof) to UE 1421 and receiving a message m1507 containing the requested timing information from UE 1421. The timing information may include ACS-specific K... offset Public TA, K mac In addition, the timing information may include the TA value of the UE toward each ACS. The UE can provide timing information for up to N ACSs, where N can be hard-coded in the specification, configured by the serving base station, or determined according to the UE's capabilities. Among all detected / reported ACSs, one of the ACSs is the serving ACS that provides the UE with a control connection, upon which the UE has established its connection to the network (in this example, ACS 1401 is the serving ACS). For each ACS, the UE obtains the associated timing information by, for example, measuring the downlink (DL) radio signals transmitted by that ACS (e.g., synchronization signals, SS / PBCH, or CSI-RS, etc.) and / or reading the system information broadcast by that ACS (e.g., System Information Block (SIB)).

[0130] In another example, as an alternative or supplementary method for the UE to provide timing information to the LS 1430, the ACS can provide timing information to the LS. The timing information may include K. offset Public TA, K mac If the ACS providing timing information is the UE's serving ACS, then that ACS can also provide the UE's TA to the LS. Even if the satellite is not involved in any positioning process, the ACS can still provide timing information to the LS. Alternatively, the UE can send a signaling message to the serving ACS requesting that this serving satellite send timing information to the LS.

[0131] After receiving timing information (from the UE and / or one or more ACSs), LS 1430 uses the obtained timing information to select one or more non-serving ACSs with the same or similar timing as ACS 1401 (serving ACS) (e.g., the same or similar propagation delay toward the UE) (step s1508). Using the timing information (e.g., K... offset Public TA, K mac This is used to determine (e.g., estimate) the propagation delay between the UE and each ACS.

[0132] In the example, if both the non-service ACS and the service ACS have similar K... offset Values ​​(e.g., K of two ACS) offset If the difference in values ​​is less than a given threshold, then the non-service ACS gives a similar propagation delay to the service ACS. In another example, if both the non-service ACS and the service ACS have similar RTTs (equal to K), then...offset Add K mac If the difference between the RTT values ​​of the two ACSs is less than a given threshold, then the non-service ACS will give a similar propagation delay as the service ACS.

[0133] After selecting an ACS, LS 1430 calculates the duration of the time window (TWD) for that ACS for each selected ACS using, for example, one of the TWD equations described above (step s1510).

[0134] LS 1430 further sends positioning configurations to each selected ACS (e.g., to the TRP on the ACS's AV or to the TRP on the ACS's GW) and the UE (see [link to CSS configuration]). Figure 15 The location configuration may include at least SRS resource configuration (e.g., information identifying the SRS, time resources that the UE will use to transmit the SRS, and frequency resources that the UE will use to transmit the SRS) and measurement window configuration, which includes the calculated TWD. The configuration provided to the UE may include at least the SRS resource configuration.

[0135] When a UE receives a positioning configuration that includes SRS resource configuration and time window configuration for ACS, it may forward the positioning configuration to the ACS if the ACS has not yet received the configuration from LS 1430.

[0136] The UE begins transmitting SRS to the ACS based on the received positioning configuration. In one embodiment, each ACS should initiate a measurement window (also known as a receive window) sufficiently early before the expected arrival time of the SRS transmitted by the UE. Each ACS can determine when to initiate the window based on the time when the UE will begin transmitting SRS. Alternatively, the LS 1430 can signal the time offset relative to the SRS transmission time to the ACS, based on which the ACS can determine the start time of the measurement window. Each ACS should remain active for the duration of the window (also known as the window period) to avoid missing corresponding SRS transmissions initiated by the receive UE.

[0137] Each ACS obtains positioning measurements for the SRS. For example, regarding ACS 1401, depending on the selected architecture, either TRP 1411 or TRP 1436 obtains positioning measurements. Furthermore, if the ACS is further configured to transmit a DL Positioning Reference Signal (PRS), the UE can obtain positioning measurements based on the PRS transmitted by the ACS. After the UE and each ACS send positioning measurements to LS 1430 (see messages m1520, m1521, and m1522), LS 1430 can calculate the UE's location.

[0138] Any signaling exchanged between the UE and the location server may be carried via one of the following methods: LPP message or Non-Access Stratum (NAS) message. Any signaling exchanged between the base station (e.g., gNB) and the location server may be carried via one of the following signaling alternatives: NRPPa message or NGAP signaling.

[0139] Figure 16 This is a flowchart illustrating process 1600 according to an embodiment for locating a UE. Process 1600 is performed by ACS 1401 (hereinafter referred to as the first ACS). Process 1600 may begin in step s1602.

[0140] Step s1602 includes obtaining information indicating the duration of the time window (TWD) for the first ACS, wherein the TWD for the first ACS is determined based on timing information for the first ACS and timing information for the second ACS (e.g., ACS 1402).

[0141] Step s1604 includes performing a positioning measurement procedure based on the indicated TWD within a first window period.

[0142] In some embodiments, the first ACS includes AV 1441 and GW 1434, and AV 1441 includes TRP 1411, and the method is performed by AV 1441.

[0143] In some embodiments, the first ACS includes AV 1441 and GW 1434, and GW 1434 includes TRP 1436, and the method is performed by GW.

[0144] In some embodiments, the first ACS is a service ACS serving the UE, or the second ACS is a service ACS serving the UE.

[0145] In some embodiments, the timing information for the first ACS includes a first offset value and / or a first timing advance value, and the timing information for the second ACS includes a second offset value and / or a second timing advance value.

[0146] In some embodiments, the TWD for the first ACS is determined by calculating the following: K offset_ACS1 -K offset_ACS2 K offset_ACS1 It is the first offset value, and K offset_ACS2 It is the second offset value.

[0147] In some embodiments, the positioning measurement process includes attempting to obtain positioning measurements within a first window period.

[0148] In some embodiments, the method further includes the first ACS obtaining positioning measurements within a first window period, and the method optionally further includes the first ACS obtaining positioning measurements within N other window periods, where N≥1.

[0149] In some embodiments, the first ACS does not obtain a location measurement within a first window period, and as a result of not obtaining a location measurement within the first window period, the method further includes the first ACS attempting to obtain a location measurement within a second window period.

[0150] Figure 17 This is a flowchart illustrating process 1700 performed by UE 1421 according to an embodiment. Process 1700 may begin in step s1702.

[0151] Step s1702 includes receiving reference signal configuration information indicating reference signal resources.

[0152] Step s1704 includes obtaining first timing information for the first ACS (e.g., ACS 1401).

[0153] Step s1706 includes obtaining second timing information for the second ACS (e.g., ACS 1402).

[0154] Step s1708 includes providing first and second timing information to a location server (e.g., LS 1430), a first ACS, and / or a second ACS.

[0155] Step s1710 includes transmitting (s1710) a reference signal using the indicated reference signal resource after providing timing information.

[0156] In some embodiments, the first ACS is a service ACS serving the UE, or the second ACS is a service ACS serving the UE.

[0157] In some embodiments, the timing information for the first ACS includes a first offset value and / or a first timing advance value, and the timing information for the second ACS includes a second offset value and / or a second timing advance value.

[0158] Figure 18 This is a flowchart illustrating process 1800 performed by LS 1430 according to an embodiment. Process 1800 may begin in step s1802.

[0159] Step s1802 includes receiving a location service request related to a user equipment (UE) (1421), wherein the UE is being served by a serviced air communication system ACS (1401, 1402).

[0160] Step s1804 includes determining whether a first non-serving ACS (e.g., ACS 1401 or ACS 1402) should be configured to perform position measurements at least for a first reference signal to be transmitted by the UE, wherein the determination is based on first timing information indicating the propagation delay between the UE and the serving ACS and second timing information indicating the propagation delay between the UE and the first non-serving ACS.

[0161] In some embodiments, the method further includes: obtaining first timing information and second timing information before determining whether a first non-service ACS should be configured to perform location measurements.

[0162] In some embodiments, obtaining the first timing information and the second timing information includes: transmitting a request message to the UE and receiving a response message in response to the request message, wherein the response message includes the first and second timing information.

[0163] In some embodiments, the method further includes: as a result of determining that a first non-service ACS should be configured to perform location measurements, initiating the provision of location configuration to the first non-service ACS.

[0164] In some embodiments, the method further includes: calculating the duration of a time window for the first non-service ACS using at least some first timing information and at least some second timing information before initiating the provision of location configuration to the first non-service ACS.

[0165] In some embodiments, the first timing information includes a first offset value and / or a first timing advance value, and the second timing information includes a second offset value and / or a second timing advance value.

[0166] In some embodiments, the determination is based on the difference between the propagation delay between the UE and the serving ACS and the propagation delay between the UE and the first non-serving ACS.

[0167] In some embodiments, the determination is based on the difference between the propagation delay between the UE and the serving ACS and the propagation delay between the UE and the first non-serving ACS.

[0168] Figure 19 This is a block diagram of a location server 1430 according to some embodiments. For example... Figure 19As shown, location server 1430 may include: processing circuitry (PC) 1902, which may include one or more processors (P) 1955 (e.g., one or more general-purpose microprocessors and / or one or more other processors, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc.), which may coexist in a single enclosure or a single data center, or may be geographically distributed (e.g., location server 1430 may be a distributed computing device including two or more computers, or a monolithic computing device consisting of a single computer); at least one network interface 1948 (e.g., a physical interface or an air interface). The location server 1430 includes a transmitter (Tx) 1945 and a receiver (Rx) 1947 for enabling the location server 1430 to transmit and receive data from other nodes connected to the network 110 (e.g., an Internet Protocol (IP) network), a network interface 1948 (physically or wirelessly) connected to the network 110 (e.g., the network interface 1948 may be coupled to an antenna arrangement including one or more antennas to enable the location server 1430 to wirelessly transmit / receive data); and a storage unit (also referred to as a “data storage system”) 1908, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments where the PC 1902 includes a programmable processor, a computer-readable storage medium (CRSM) 1942 may be provided. The CRSM 1942 may store a computer program (CP) 1943 including computer-readable instructions (CRI) 1944. CRSM 1942 may be a non-transitory computer-readable medium, such as magnetic media (e.g., hard disk), optical media, memory devices (e.g., random access memory, flash memory), etc. In some embodiments, CRI 1944 of computer program 1943 is configured such that when executed by PC 1902, CRI causes location server 1430 to perform the steps described herein (e.g., the steps described herein with reference to the flowcharts). In other embodiments, location server 1430 may be configured to perform the steps described herein without requiring code. That is, for example, PC 1902 may consist of only one or more ASICs. Therefore, the features of the embodiments described herein may be implemented in hardware and / or software.

[0169] Figure 20 This is a block diagram of UE 1421 according to some embodiments. For example... Figure 20As shown, UE 1421 may include: processing circuitry (PC) 2002, which may include one or more processors (P) 2055 (e.g., one or more general-purpose microprocessors and / or one or more other processors, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc.); communication circuitry 2048, coupled to an antenna arrangement 2049 including one or more antennas, and including a transmitter (Tx) 2045 and a receiver (Rx) 2047 for enabling UE 1421 to transmit and receive data (e.g., wirelessly transmit / receive data); and a storage unit (also referred to as a "data storage system") 2008, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments where PC 2002 includes a programmable processor, a computer-readable storage medium (CRSM) 2042 may be provided. CRSM 2042 may store a computer program (CP) 2043 including computer-readable instructions (CRI) 2044. CRSM 2042 may be a non-transitory computer-readable medium, such as magnetic media (e.g., hard disk), optical media, memory devices (e.g., random access memory, flash memory), etc. In some embodiments, CRI 2044 of computer program 2043 is configured such that when executed by PC 2002, CRI causes UE 1421 to perform the steps described herein (e.g., the steps described herein with reference to the flowcharts). In other embodiments, UE 1421 may be configured to perform the steps described herein without requiring code. That is, for example, PC 2002 may consist of only one or more ASICs. Therefore, the features of the embodiments described herein may be implemented in hardware and / or software.

[0170] Figure 21 This is a block diagram of a base station 2100 (e.g., TRP1411, 1412, 1424, or 1436) according to some embodiments for performing the TRP methods disclosed herein. Figure 21As shown, base station 2100 may include: processing circuitry (PC) 2102, which may include one or more processors (P) 2155 (e.g., one or more general-purpose microprocessors and / or one or more other processors, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), etc.), which may coexist in a single enclosure or a single data center, or may be geographically distributed (i.e., the base station may be a distributed computing device or a monolithic computing device); network interface 2168, which includes a transmitter (Tx) 2165 and a receiver (Rx) 2167, for enabling base station 2100 to transmit data to and receive data from other nodes connected to network 110 (e.g., an Internet Protocol (IP) network), network interface 2168 being connected to network 110; and communication circuitry 2148 (e.g., including Rx 2147 and Tx 2155). 2145 includes a radio transceiver circuitry coupled to an antenna system 2149 for wireless communication with a UE or other nodes; and a storage unit (also referred to as a “data storage system”) 2108, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments where PC 2102 includes a programmable processor, a computer-readable storage medium (CRSM) 2142 may be provided. CRSM 2142 may store a computer program (CP) 2143 including computer-readable instructions (CRI) 2144. CRSM 2142 may be a non-transitory computer-readable medium, such as a magnetic medium (e.g., a hard disk), an optical medium, a memory device (e.g., random access memory, flash memory), etc. In some embodiments, the CRI 2144 of the computer program 2143 is configured such that, when executed by PC 2102, the CRI causes base station 2100 to perform the steps described herein (e.g., steps described herein with reference to one or more flowcharts). In other embodiments, base station 2100 may be configured to perform the steps described herein without requiring code. In other words, for example, PC 2102 may consist of only one or more ASICs. Therefore, the features of the embodiments described herein can be implemented in hardware and / or software.

[0171] Overview of various embodiments A1. A method for locating a UE, the method being performed by a first ACS (e.g., by a base station of the first ACS) and comprising: obtaining information indicating a time window duration (TWD) for the first ACS, wherein the TWD for the first ACS is determined based on timing information for the first ACS and timing information for a second ACS; wherein the first ACS is configured to acquire (or attempt to acquire) a location measurement within the window period based on the indicated TWD.

[0172] A2. The method of embodiment A1, wherein the first ACS includes a first airborne vehicle (AV) and a first gateway (GW), the first AV includes a base station, and the method is performed by the base station on the first AV board.

[0173] A3. The method of embodiment A1, wherein the first ACS includes a first airborne vehicle AV and a first gateway GW, the first GW includes a base station, and the method is performed by the base station of the GW.

[0174] A4. The method of embodiment A1, A2 or A3, wherein the first ACS is a service ACS serving the UE, or the second ACS is a service ACS serving the UE.

[0175] A5. A method of any one of embodiments A1-A4, wherein the timing information includes: a first offset value associated with the service ACS (e.g., K). offset ), second offset value (e.g., K) mac ), a first timing advance value (e.g., common TA) and / or a second timing advance value (e.g., UE's TA), and / or a first offset value associated with a non-service ACS (e.g., K). offset The first timing advance value (e.g., Kmac), the second timing advance value (e.g., common TA), and / or the second timing advance value (e.g., UE's TA).

[0176] A6. A method of any one of embodiments A1-A6, wherein the method further comprises: a first ACS attempting to obtain a positioning measurement within a window period based on the indicated TWD.

[0177] A7. The method of embodiment A6, wherein the method further includes: the first ACS obtaining positioning measurements within a window period.

[0178] A8. The method of embodiment A6, wherein the method further includes: a first ACS failing to obtain a location measurement during the window period; and, as a result of failing to obtain a location measurement during the window period, attempting to obtain a location measurement during a second window period.

[0179] A9. An ACS configured to perform the method of any one of embodiments A1-A8.

[0180] B1. A method performed by UE 1421, the method comprising: receiving reference signal configuration information indicating reference signal resources; obtaining first timing information for a first ACS; obtaining second timing information for a second ACS; providing the first and second timing information to a location server, a first ACS 1401 and / or the second ACS; and transmitting a reference signal using the indicated reference signal resources after providing the timing information.

[0181] B2. The method of embodiment B1, wherein the first ACS is a service ACS serving the UE, or the second ACS is a service ACS serving the UE.

[0182] B3. The method of embodiment B1 or B2, wherein the timing information includes: a first offset value associated with the service ACS (e.g., K). offset ), second offset value (e.g., K) mac ), a first timing advance value (e.g., common TA) and / or a second timing advance value (e.g., UE's TA), and / or a first offset value associated with a non-service ACS (e.g., K). offset ), second offset value (e.g., K) mac ), a first timing advance value (e.g., common TA) and / or a second timing advance value (e.g., UE's TA).

[0183] B4. A UE configured to perform the method of embodiment B1, B2, or B3.

[0184] C1. A method performed by a location server, the method comprising: receiving a location service request relating to a UE, wherein the UE is being served by a serving ACS; and determining whether a first non-serving ACS should be configured to perform location measurements at least for a first reference signal to be transmitted by the UE, wherein the determination is based on first timing information indicating a propagation delay between the UE and the serving ACS and second timing information indicating a propagation delay between the UE and the first non-serving ACS.

[0185] C2. The method of embodiment C1, wherein the method further includes: obtaining first timing information and second timing information before determining whether a first non-service ACS should be configured to perform location measurement.

[0186] C3. The method of embodiment C2, wherein obtaining the first timing information and the second timing information includes transmitting a request message to the UE and receiving a response message in response to the request message, and the response message includes the first and second timing information.

[0187] C4. A method of any one of embodiments C1-C3, wherein the method further includes: as a result of determining that a first non-service ACS should be configured to perform location measurement, initiating the provision of location configuration to the first non-service ACS.

[0188] C5. The method of embodiment C4, wherein the method further includes: calculating the duration of a time window for the first non-service ACS using at least some first timing information and at least some second timing information before initiating the provision of location configuration to the first non-service ACS.

[0189] C6. A method of any one of embodiments C1-C5, wherein the timing information includes: a first offset value associated with the service ACS (e.g., K). offset ), second offset value (e.g., K) mac ), a first timing advance value (e.g., common TA) and / or a second timing advance value (e.g., UE's TA), and / or a first offset value associated with a non-service ACS (e.g., K). offset ), second offset value (e.g., K) mac ), a first timing advance value (e.g., common TA) and / or a second timing advance value (e.g., UE's TA).

[0190] C7. A location server configured to perform the method of any one of embodiments C1-C6.

[0191] D1. A computer program including instructions executable by processing circuitry of a device for configuring the device to perform any of the methods described above.

[0192] D2. A carrier comprising a computer program of embodiment D1, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium.

[0193] in conclusion As described herein, this disclosure describes selection criteria for selecting satellites / TRPs (e.g., selecting satellites with the same or similar timing) to participate in the positioning process for locating the UE. Furthermore, a window is configured for each satellite to accommodate timing differences between satellites. During the window period, the UE transmits one or more SRS signals to ensure that at least one SRS transmission is received from each satellite, thereby enabling the acquisition of the corresponding UL measurement. Additionally, timing information can be exchanged between the UE and the LMF, between satellites and LMFs, and between satellites.

[0194] While various embodiments have been described herein, it should be understood that they have been presented by way of example only and not as limitations. Therefore, the breadth and scope of this disclosure should not be limited to any of the exemplary embodiments described above. Furthermore, unless otherwise indicated herein or clearly contradicted by the context, this disclosure covers any combination of the foregoing elements in all possible variations.

[0195] As used herein, sending a message "to" or "towards" the intended recipient encompasses delivering the message directly to the intended recipient or delivering the message indirectly to the intended recipient (i.e., relaying the message from the source node to the intended recipient using one or more other nodes). Similarly, as used herein, receiving a message "from" the sender encompasses receiving the message directly from the sender or receiving the message indirectly from the sender (i.e., relaying the message from the sender to the receiving node using one or more nodes). Furthermore, as used herein, "a" means "at least one" or "one or more".

[0196] Furthermore, although the processes described above and shown in the accompanying figures are presented as a sequence of steps, this is merely for illustration purposes. Therefore, it should be considered that some steps may be added, some steps may be omitted, the order of the steps may be rearranged, and some steps may be performed in parallel.

Claims

1. A method (1600) for locating a user equipment (UE) (1421), the method being performed by a first air communication system (ACS) (1401), and the method comprising: Obtain (s1602) information indicating the duration of the time window (TWD) for the first ACS, wherein the TWD for the first ACS is determined based on timing information for the first ACS and timing information for the second ACS (1402); and The positioning measurement process (s1604) is performed within the first window period based on the indicated TWD.

2. The method according to claim 1, wherein, The first ACS (1401) includes a first airborne vehicle AV (1441) and a first gateway GW (1434). The first AV includes a transmit and receive point TRP (1411), and The method is executed by the first AV.

3. The method according to claim 1, wherein, The first ACS (1401) includes a first airborne vehicle AV (1441) and a first gateway GW (1434). The first GW includes a transmit and receive point TRP (1436), and The method is executed by the GW.

4. The method according to claim 1, 2, or 3, wherein, The first ACS is a service ACS that serves the UE, or The second ACS is a service ACS that serves the UE.

5. The method according to any one of claims 1-4, wherein, The timing information used for the first ACS includes a first offset value and / or a first timing advance value, and The timing information used for the second ACS includes a second offset value and / or a second timing advance value.

6. The method according to claim 5, wherein, The TWD used for the first ACS is determined by calculating the following: K offset_ACS1 -K offset_ACS2 ,in K offset_ACS1 It is the first offset value, and K offset_ACS2 It is the second offset value.

7. The method according to any one of claims 1-6, wherein, The positioning measurement process includes attempting to obtain positioning measurements within the first window period.

8. The method according to claim 7, wherein, The method further includes the first ACS obtaining the positioning measurement within the first window period, and The method may optionally further include the first ACS obtaining positioning measurements during N other window periods, where N≥1.

9. The method according to claim 7, wherein, The first ACS did not obtain the positioning measurement within the first window period, and As a result of not obtaining the positioning measurement within the first window period, the method further includes the first ACS attempting to obtain the positioning measurement within a second window period.

10. A first air communication system (ACS) (1401), the first ACS being configured to perform a process including the following operations: Obtain (s1602) information indicating the duration TWD of the time window for the first ACS, wherein, The TWD used for the first ACS is determined based on the timing information used for the first ACS and the timing information used for the second ACS (1402); as well as The positioning measurement process (s1604) is performed within the first window period based on the indicated TWD.

11. The first ACS according to claim 10, wherein, The first ACS is further configured to perform the method according to any one of claims 2-9.

12. A method (1700) performed by a user equipment (UE) (1421), the method comprising: Receive (s1702) reference signal configuration information indicating reference signal resources; Obtain (s1704) the first timing information for the first air communication system ACS (1401); Obtain (s1706) the second timing information for the second ACS (1402); Provide (s1708) the first timing information and the second timing information to the location server (1430), the first ACS (1401) and / or the second ACS (1402); as well as After providing the timing information, the reference signal is transmitted (s1710) using the indicated reference signal resource.

13. The method according to claim 12, wherein, The first ACS is a service ACS that serves the UE, or The second ACS is a service ACS that serves the UE.

14. The method according to claim 12 or 13, wherein, The timing information used for the first ACS includes a first offset value and / or a first timing advance value, and The timing information used for the second ACS includes a second offset value and / or a second timing advance value.

15. A user equipment (UE) (1421) configured to perform a method comprising the following operations: Receive (s1702) reference signal configuration information indicating reference signal resources; Obtain (s1704) the first timing information for the first air communication system ACS (1401); Obtain (s1706) the second timing information for the second ACS (1402); Provide (s1708) the first timing information and the second timing information to the location server (1430), the first ACS (1401), and / or the second ACS (1402); and After providing the timing information, the reference signal is transmitted (s1710) using the indicated reference signal resource.

16. The UE according to claim 15, wherein, The timing information used for the first ACS includes a first offset value and / or a first timing advance value, and The timing information used for the second ACS includes a second offset value and / or a second timing advance value.

17. A method (1800) performed by a location server (1430), the method comprising: Receive (s1802) a location service request related to user equipment (UE) (1421), wherein the UE is being served by a serving air communication system ACS (1401, 1402); and Determine (s1804) whether the first non-service ACS (1401, 1402) should be configured to perform position measurement at least for the first reference signal to be transmitted by the UE, wherein, The determination is based on first timing information indicating the propagation delay between the UE and the serving ACS and second timing information indicating the propagation delay between the UE and the first non-serving ACS.

18. The method according to claim 17, wherein, The method further includes: obtaining the first timing information and the second timing information before determining whether the first non-service ACS should be configured to perform the location measurement.

19. The method according to claim 18, wherein, Obtaining the first timing information and the second timing information includes transmitting a request message to the UE and receiving a response message in response to the request message, and The response message includes the first timing information and the second timing information.

20. The method according to any one of claims 17-19, wherein, The method further includes: as a result of determining that a first non-service ACS should be configured to perform the location measurement, initiating the provision of a location configuration to the first non-service ACS.

21. The method according to claim 20, wherein, The method further includes: before initiating the provision of location configuration to the first non-service ACS, using at least some of the first timing information and at least some of the second timing information to calculate the duration of a time window for the first non-service ACS.

22. The method according to any one of claims 17-21, wherein, The first timing information includes a first offset value and / or a first timing advance value, and The second timing information includes a second offset value and / or a second timing advance value.

23. The method according to any one of claims 17-22, wherein, The determination is based on the difference between the propagation delay between the UE and the serving ACS and the propagation delay between the UE and the first non-serving ACS.

24. The method according to claim 23, wherein, The determination is based on the difference between the propagation delay between the UE and the serving ACS and the propagation delay between the UE and the first non-serving ACS.

25. A location server (1430) configured to perform a method comprising the following operations: Receive (s1802) a location service request related to the user equipment (UE) (1421), wherein, The UE is being served by the Serving Air Communication System (ACS) (1401, 1402); and Determine (s1804) whether the first non-service ACS (1401, 1402) should be configured to perform position measurement at least for the first reference signal to be transmitted by the UE, wherein, The determination is based on first timing information indicating the propagation delay between the UE and the serving ACS and second timing information indicating the propagation delay between the UE and the first non-serving ACS.

26. The first location server according to claim 25, wherein, The location server is further configured to perform the method according to any one of claims 18-24.

27. A computer program including instructions executable by processing circuitry of a device for configuring the device to perform the method according to any one of the preceding claims.

28. A carrier comprising the computer program according to claim 27, wherein, The carrier is one of electronic signals, optical signals, radio signals, and computer-readable storage media.

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