Reference location propagation in ntn

Abstract

A method includes checking whether a received movement indication indicates that a location of a reference position associated with a satellite will be autonomously updated for mobility decisions; if the movement indication indicates that the location is to be updated, updating the location of the reference position based on the initial location, the point in time, the current time, and the ephemeris of the satellite; determining a distance between the current location of the terminal and the update location; deciding whether a condition for performing a mobility action by the terminal is satisfied; wherein, if at least one of the following is applicable:-the distance is greater than a first threshold, and the mobility action is distant from the cell,-if at least one of the following is applicable,-the mobility action is inhibited from being performed by the terminal; or-the distance is less than a second threshold, and the mobility action is towards the cell.

Description

Technical Field

[0001] The present disclosure relates to mobility in NTN.

[0002] abbreviation Background Art

[0003] Rel-17 introduced additional handover (HO) triggers, such as time and distance. In Rel-18, the time T1 and distance D1 triggers are combined with the conditional radio events condEventA3, CondEventA4, and CondEventA5 in the conditional handover (CHO) configuration. When a time or distance trigger is added to a conditional handover configuration, the UE must observe that this condition is triggered simultaneously with the radio condition before performing the handover. For the location-based trigger CondEvent D1, the UE evaluates two distance-based conditions based on its own location, as well as referenceLocation1 and referenceLocation2: whether the distance to the reference location of the serving cell (referenceLocation1) is greater than a first threshold, and whether the distance to the reference location of the candidate target cell (referenceLocation2) is less than a second threshold. The reference locations (referenceLocation1 and referenceLocation2) are defined relative to the source cell and target cell, respectively. They each define a corresponding location on the Earth, which can be associated with the center of the cell coverage area, for example. The reference location is included in the IEReferenceLocation, as defined in 3GPP TS 38.331. Summary of the Invention

[0004] The object of the present invention is to improve the prior art.

[0005] According to a first aspect, there is provided an apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the one or more processors, cause the apparatus to at least: receiving an implicit or explicit first dynamic mobility indication indicating whether a location of a first reference position is to be autonomously updated for use in mobility decisions of the terminal, wherein the first reference position is defined relative to a first cell of a first satellite; checking whether the first dynamic mobility indication indicates that the location of the first reference position is to be autonomously updated for use in the mobility decision; in response to checking that the first dynamic mobility indication indicates that the location of the first reference location is to be autonomously updated for the mobility determination, updating the location of the first reference location based on one of the ephemeris of the first satellite and another location of the first reference location together with a second point in time when the first reference location was at the another location, an initial location of the first reference location, a first point in time when the first reference location was at the initial location, and a current time; determining a first distance between a current location of the terminal and the updated location of the first reference location; determining whether a first condition for performing a mobility action by the terminal is satisfied; In response to determining that the first condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the first reference location and the current location of the terminal are indicated as locations on Earth; The mobility decision is used to determine whether the mobility action can be performed; The first condition is met if at least one of the following applies: - the first distance is greater than a first threshold, and the mobility action is to move away from the first cell; or - The first distance is less than a second threshold, and the mobility action is towards the first cell.

[0006] The instructions, when executed by the at least one processor, may further cause the apparatus to: receiving an implicit or explicit second dynamic mobility indication indicating whether a location of a second reference position is to be autonomously updated for use in the mobility decision, wherein the second reference position is defined relative to a second cell of a second satellite; checking whether the second dynamic mobility indication indicates that the location of the second reference position is to be autonomously updated for use in the mobility decision; in response to checking that the second dynamic mobility indication indicates that the location of the second reference position is to be autonomously updated for the mobility determination, updating the location of the second reference position based on one of the ephemeris of the second satellite and another location of the second reference position together with a fourth point in time at which the second reference position was at the another location, an initial location of the second reference position, a third point in time at which the second reference position was at the initial location, and a current time; determining a second distance between the estimated current location of the terminal and the updated position of the second reference location; determining whether a second condition for performing the mobility action by the terminal is satisfied; In response to determining that the second condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the second reference position is indicated as a location on Earth; If the mobility action is to move away from the first cell, then if the second distance is less than a third threshold, the second condition is satisfied; If the mobility action is towards the first cell, the second condition is met if the second distance is greater than a fourth threshold.

[0007] The instructions, when executed by the at least one processor, may further cause the apparatus to: determining whether an absolute value of a difference between the first distance and the first threshold is less than a fifth threshold; AND at least one of the following: - in response to determining that the absolute value of the difference between the first distance and the first threshold is less than a fifth threshold, calculating the updated location of the first reference position with a first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, calculating the updated location of the first reference position with a second frequency; or - in response to checking that the absolute value of the difference between the first distance and the first threshold is smaller than the fifth threshold, estimating the current location of the terminal at the first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not smaller than the fifth threshold, estimating the current location of the terminal at the second frequency; and The instructions, when executed by the at least one processor, cause the apparatus to: in response to checking that the absolute value of the difference between the first distance and the first threshold is smaller than the fifth threshold, deciding whether the first condition for performing the mobility action by the terminal is satisfied at the first frequency; In response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, deciding whether the first condition for performing the mobility action by the terminal is satisfied at the second frequency; wherein, The second frequency is lower than the first frequency.

[0008] The instructions, when executed by the at least one processor, may cause the apparatus to perform the receiving of the implicit first dynamic movement indication by at least one of: - an indication of an end time for determining coverage availability of the first cell is not configured; - monitoring said first cell on a frequency layer different from each of the one or more terrestrial frequency bands according to a stored frequency table.

[0009] At least one of the following may apply: - the mobility decision comprises a decision regarding a conditional handover, and the mobility action comprises the conditional handover; or - the mobility decision comprises a decision regarding cell reselection, and the mobility action comprises the cell reselection.

[0010] The instructions, when executed by the at least one processor, may cause the apparatus to estimate a current location of the terminal.

[0011] According to a second aspect, there is provided an apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform the following operations: instructing the terminal to autonomously calculate an updated location of the reference position of the cell of the satellite based on one of the other location of the reference position together with the second time point at which the reference position of the cell of the satellite is at the other location, the initial location of the reference point, the first time point at which the reference point is at the initial location, and the current time, wherein The reference position is defined relative to the cell.

[0012] The instructions, when executed by the at least one processor, may further cause the apparatus to: The initial location of the reference position of the cell is provided to the terminal.

[0013] The instructions, when executed by the at least one processor, may further cause the apparatus to: An indication is provided to the terminal that the reference location is at the first point in time at the initial location.

[0014] The instructions, when executed by the at least one processor, may further cause the apparatus to: At least one of the ephemeris of the satellite and the other location of the reference position of the cell is provided to the terminal.

[0015] The instructions, when executed by the at least one processor, may further cause the apparatus to: An indication is provided to the terminal that the reference location is at the second point in time at the other location.

[0016] The instructions, when executed by the at least one processor, may further cause the apparatus to: If the distance between the autonomous update location of the reference point and the current location of the terminal is out of range, the terminal is prohibited from performing a mobility action.

[0017] The mobility action may include at least one of conditional handover and cell reselection.

[0018] At least one of the following may apply: if the distance between the updated location of the reference point and the position of the terminal is less than a first threshold and the mobility action is away from the cell, the distance is out of range; or If the distance between the updated location of the reference point and the position of the terminal is greater than a second threshold, and the mobility action is towards the cell, the distance is out of range.

[0019] According to a third aspect, there is provided a method comprising: receiving an implicit or explicit first dynamic mobility indication indicating whether a location of a first reference position is to be autonomously updated for use in mobility decisions of the terminal, wherein the first reference position is defined relative to a first cell of a first satellite; checking whether the first dynamic mobility indication indicates that the location of the first reference position is to be autonomously updated for use in the mobility decision; in response to checking that the first dynamic mobility indication indicates that the location of the first reference location is to be autonomously updated for use in the mobility determination, updating the location of the first reference location based on one of the ephemeris of the first satellite and another location of the first reference location together with a second point in time at which the first reference location was at the other location, an initial location of the first reference location, a first point in time at which the first reference location was at the initial location, and a current time; determining a first distance between a current location of the terminal and the updated location of the first reference location; determining whether a first condition for performing a mobility action by the terminal is satisfied; In response to determining that the first condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the first reference location and the current location of the terminal are indicated as locations on Earth; The mobility decision is used to determine whether the mobility action can be performed; The first condition is met if at least one of the following applies: - the first distance is greater than a first threshold, and the mobility action is to move away from the first cell; or - The first distance is less than a second threshold, and the mobility action is towards the first cell.

[0020] The method may further comprise: receiving an implicit or explicit second dynamic mobility indication indicating whether a location of a second reference position is to be autonomously updated for use in the mobility decision, wherein the second reference position is defined relative to a second cell of a second satellite; checking whether the second dynamic mobility indication indicates that the location of the second reference position is to be autonomously updated for use in the mobility decision; in response to checking that the second dynamic mobility indication indicates that the location of the second reference position is to be autonomously updated for the mobility determination, updating the location of the second reference position based on one of the ephemeris of the second satellite and another location of the second reference position together with a fourth point in time when the second reference position is at the another location, an initial location of the second reference position, a third point in time when the second reference position is at the initial location, and a current time; determining a second distance between the estimated current location of the terminal and the updated position of the second reference location; determining whether a second condition for performing the mobility action by the terminal is satisfied; In response to determining that the second condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the second reference position is indicated as a location on Earth; If the mobility action is to move away from the first cell, then if the second distance is less than a third threshold, the second condition is satisfied; If the mobility action is towards the first cell, the second condition is met if the second distance is greater than a fourth threshold.

[0021] The method may further comprise: determining whether an absolute value of a difference between the first distance and the first threshold is less than a fifth threshold; AND at least one of the following: - in response to determining that the absolute value of the difference between the first distance and the first threshold is less than a fifth threshold, calculating the updated location of the first reference position with a first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, calculating the updated location of the first reference position with a second frequency; or - in response to checking that the absolute value of the value between the first distance and the first threshold is less than the fifth threshold, estimating the current location of the terminal at the first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, estimating the current location of the terminal at the second frequency; the determining, in response to checking that the absolute value of the difference between the first distance and the first threshold is smaller than the fifth threshold, whether the first condition for performing the mobility action by the terminal is satisfied at the first frequency; In response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, determining whether the first condition for performing the mobility action by the terminal is satisfied at the second frequency; wherein, The second frequency is lower than the first frequency.

[0022] The method may further comprise: The receiving the implicit first dynamic movement indication is performed by at least one of the following: - an indication of an end time for determining coverage availability of the first cell is not configured; - monitoring said first cell on a frequency layer different from each of the one or more terrestrial frequency bands according to a stored frequency table.

[0023] At least one of the following may apply: - the mobility decision comprises a decision regarding a conditional handover, and the mobility action comprises the conditional handover; or - the mobility decision comprises a decision regarding cell reselection, and the mobility action comprises the cell reselection.

[0024] The method may further comprise: The current location of the terminal is estimated.

[0025] According to a fourth aspect, there is provided a method comprising: Instructing the terminal to autonomously calculate an updated location of the reference position of the cell of the satellite based on one of the ephemeris of the satellite and another location of the reference position together with a second time point when the reference position of the cell of the satellite is at the another location, an initial location of the reference point, a first time point when the reference point is at the initial location, and a current time, wherein The reference position is defined relative to the cell.

[0026] The method may further comprise: The initial location of the reference position of the cell is provided to the terminal.

[0027] The method may further comprise: An indication is provided to the terminal that the reference location is at the first point in time at the initial location.

[0028] The method may further comprise: At least one of the ephemeris of the satellite and the other location of the reference position of the cell is provided to the terminal.

[0029] The method may further comprise: An indication is provided to the terminal that the reference location is at the second point in time at the other location.

[0030] The method may further comprise: If a distance between the autonomous update location at the reference point and a current location of the terminal is out of range, the terminal is prohibited from performing a mobility action.

[0031] The mobility action may include at least one of conditional handover and cell reselection.

[0032] At least one of the following may apply: if the distance between the updated location of the reference point and the position of the terminal is less than a first threshold and the mobility action is away from the cell, the distance is out of range; or If the distance between the updated location of the reference point and the position of the terminal is greater than a second threshold, and the mobility action is towards the cell, the distance is out of range.

[0033] Each of the methods described in the third or fourth aspect may be a reference position propagation method.

[0034] According to a fifth aspect, a computer program product is provided comprising an instruction set, wherein when the instruction set is executed on a device, the device is configured to perform the method according to any one of the third aspect or the fourth aspect. The computer program product may be embodied as a computer-readable medium or directly loaded into a computer.

[0035] According to some example embodiments, at least one of the following advantages may be achieved:

[0036] It will be understood that any of the above modifications may be applied to the various aspects to which they refer, either individually or in combination, unless an alternative is explicitly stated to be excluded. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Further details, features, objects and advantages will become more apparent from the following detailed description of preferred exemplary embodiments taken in conjunction with the accompanying drawings, in which:

[0038] Figure 1 The reference position and point C that satisfy condEvent D1 in the QEF scenario are shown;

[0039] Figure 2 The reference position and point C in the traditional EM scenario are shown;

[0040] Figure 3 Methods according to some example embodiments are shown;

[0041] Figure 4 An apparatus according to an example embodiment is shown;

[0042] Figure 5 A method according to an example embodiment is shown;

[0043] Figure 6 An apparatus according to an example embodiment is shown;

[0044] Figure 7 A method according to an example embodiment is shown; and

[0045] Figure 8 An apparatus according to an example embodiment is shown. DETAILED DESCRIPTION

[0046] Hereinafter, certain exemplary embodiments will be described in detail with reference to the accompanying drawings, wherein, unless otherwise indicated, the features of these embodiments may be freely combined with each other. However, it should be clearly understood that the description of certain embodiments is given by way of example only and should not be construed as limiting the invention to the disclosed details.

[0047] Furthermore, it should be understood that although in some cases only an apparatus or method has been described, the apparatus is configured to perform the corresponding method.

[0048] For satellite cells, the reference position is described using the same coordinate system as the ellipsoid point defined in 3GPP TS 37.355. An ellipsoid point is a point on the surface of an ellipsoid that is used to define a point on or near the Earth's surface. It is typically described in latitude and longitude.

[0049] The current configuration of condEvent D1 (i.e. not continuously updating the reference position) works well in some scenarios, for example: 1. Ground scene 2. NTN scenario with geostationary satellites (GEO) 3. NTN scenario with low earth orbit satellites (LEO) equipped with quasi-geo-fixed (QEF) coverage (mainly for intra-satellite mobility events).

[0050] Figure 1 The third scenario described above is depicted in Figure 2. In this example, point C marks the point where condEvent D1 is satisfied, i.e., at "point C", the distance between the UE and referenceLocation 1 is greater than the configured threshold distanceThreshFromReference1, and the distance between the UE and referenceLocation 2 is less than the configured threshold distanceThreshFromReference2. The UE to the left of point C will benefit from the mobility event and move from cell A to cell B. Due to the QEF characteristics of satellite coverage (see Figure 1 b) This assessment may be maintained for a period of time ΔT.

[0051] In Earth Mobile Cells (EMCs), NTN cells are constantly sweeping across the Earth's surface; this means that the values ​​of referenceLocation 1 and referenceLocation 2 should change as the cell moves. However, according to the Rel-17 specification, this means that the ReportConfigNR information element sent from the satellite to the UE to indicate the cell's location on the Earth must be continuously updated, which is not supported in practice and may not be feasible.

[0052] Figure 2 This problem is shown in relation to the Earth moving scenario. Figure 2 a and Figure 2 b observed between Figure 1 a and Figure 1 b, and the value for ReferenceLocation is not updated between time T and time T+ΔT. Point C (with Figure 1 The same) is determined at time T. Figure 2 As can be seen in Figure b, point C has lost its relevance as a good location for mobility events to occur. At time T, the reference location and point C would result in the desired mobility behavior, while at time T+ΔT, the reference location and point C no longer match the coverage area of ​​the Earth mobile cell. Therefore, any mobility decision (such as conditional handover) based on an outdated reference location is undesirable.

[0053] Simulations show that applying a CHO mobility event conditioned on the dynamically updated distance between the UE and the mobile reference location can significantly improve handover performance. Specifically, it can be observed that CHO using CondEvent D1 and a dynamically updated reference location significantly outperforms both conventional HO and CHO using only the A3 CondEvent in all relevant parameters: number of radio link failures, number of HO attempts and unnecessary handovers (e.g., ping-pong handovers), and average SINR.

[0054] In Rel-17 (in NR and NB-IoT / eMTC), signaling from the gNB was introduced to indicate the orbital parameters of the satellite (including current location and orbital velocity). This signaling allows the UE to propagate the location of the satellite over time ("EphemerishInfo"). Table 1 shows the information elements as an example: Table 1: EphemerishInfo

[0055] Furthermore, Rel-17 introduces the concept of "footprint info" for NB-IoT / eMTC (in SIB32 as part of SatelliteInfo). In discontinuous coverage scenarios, footprint info indicates to the UE the approximate time of arrival of the next satellite. In practice, a UE may postpone measurement events if it finds itself in a coverage gap (in time) between a departing satellite and an incoming satellite. Table 2: Footprint Info

[0056] According to some example embodiments, the network indicates to the UE that the UE should update the reference location in the earth mobile cell scenario and apply the updated reference location in the distance-based CHO trigger. To this end, the network provides signaling to the UE, also known as "dynamic mobility indication", to indicate to the UE that the UE should use CondEvent D1 with "dynamic mobility reference location (CondEvent D1)". The signaling includes mobility information for updating the reference location over time.

[0057] The "dynamic mobility" indication may apply to one or both reference locations. For example, it may apply to only one reference location in a mobility event where one of the network nodes is not moving or is moving very slowly, such as between a GEO cell and a LEO cell, or between a LEO cell and a terrestrial network cell.

[0058] The "dynamic mobility" indication can be implicit or explicit. An example of an implicit indication is as follows: If t-service is not configured in the serving cell (e.g., not broadcast in SIB19 for NR and SIB32 for eMTC), the UE assumes that this is a geomobile cell and the CHO reference position used for this cell is of the "dynamic" type. t-service is a time-domain parameter that defines when a cell stops serving its current coverage area. This applies to geofixed cells, where the satellite continuously adjusts its beam pointing so that the cell remains fixed to a specific area on the Earth. At some point, the satellite is so low above the horizon that this adjustment is no longer feasible. The satellite then switches the beam to the next coverage area. This switch occurs at the t-service.

[0059] Another implicit indication is the frequency layer of the target cell - if it is a terrestrial band (according to data stored in the UE), the UE can assume that the target cell reference location is fixed and not moving around the earth. Examples of explicit indications include a flag associated with one or both ReferenceLocations. This flag can be set when configuring a location-based trigger or can be set separately.

[0060] Upon receiving such signaling, the UE will interpolate the referenceLocation over time based on the received mobility information and dynamically update its location trigger (CondEvent D1). As an option, a moving UE may obtain its own location (by reading GNSS location) more frequently when the UE is close to the area where CondEvent D1 is established.

[0061] The movement of the reference position may correspond to the ephemeris of the satellites broadcasting the source cell and the target cell, respectively. If the UE receives the ephemeris, the UE autonomously updates the reference position over time to follow the orbit of the satellite.

[0062] A reference location can be indicated as a "footprintInfo" type to inform the coverage area of ​​the satellite's cell: if a referencePoint of "footprintInfo" is given, the referencePoint is updated based on the satellite ephemeris to always maintain the elevation and / or azimuth between the reference point and the satellite. The referencePoint in footprintInfo corresponds to the referenceLocation used for CondEvent D1 in the CHO decision.

[0063] The initial ReferenceLocation can be indicated as an index into a referenceLocation in a referenceLocation list. For example, this list can be broadcast via a SIB. As another option, the network can provide the reference location as a function of time in the SIB. This function can correspond to orbital ephemeris but can take into account altitude relative to the Earth's surface. Instead of providing a function that enables the UE to calculate the time when the reference location is at a specific location, the list can include, for each of a plurality of reference locations, a corresponding point in time when the reference location is at that location.

[0064] When the UE must determine the next reference position based on information of type footnoteInfo referencePoint, it must link the epoch time of the ephemeris (the time at which the information is valid) to the reference position. For example, the UE knows that the satellite is at location (x, y, z) at time T1, but the initial reference position is configured at time T2. The UE then needs to know whether the reference position is given for T1 or another point in time (relative to the ephemeris), such as T2. The information about the relevant time points can be predefined, or the network (satellite) can provide such information to the UE via signaling.

[0065] The time reference used by the UE to update referenceLocation may be, for example, one of the following: • Associated with the transmission time of the satellite when the CHO is configured (including reference position information). • Associated with other time points on the radio frame (e.g. end of SIB modificationPeriod, epochTime for satellite assistance information / ephemeris, etc.).

[0066] The network may inform the UE how to perform this time reference through (explicit or implicit) signaling (eg as part of CHO configuration), or the time reference may be pre-defined, eg in 3GPP specifications.

[0067] If the UE receives signaling from the gNB including a "dynamic mobility" indication, the UE may: • If the reference location is not updated automatically (e.g. based on ephemeris), the UE may apply an “update algorithm” to one or both referenceLocations to keep the referenceLocations always updated. • A UE that moves as it approaches reaching CondEvent D1 may also acquire its own position (via GNSS positioning, i.e., GNSS position readings) and / or a reference position more frequently.

[0068] A UE may acquire (estimate) its own position based on GNSS signals, for example, by receiving and evaluating positioning reference signals from the network, or by receiving a location estimate from the network.

[0069] Figure 3 Methods according to some example embodiments are shown. Figure 3 As shown, if the UE receives a CHO configuration with an implicit or explicit dynamic mobility indication (S1), the UE checks (S2) whether the dynamic mobility indication indicates that one or both of ReferenceLocation1 and ReferenceLocation2 are moving, so that they should be dynamically updated. If the dynamic mobility indication indicates that neither ReferenceLocation1 nor ReferenceLocation2 is moving (S2=No), the reference location remains static (not updated) (S3). If at least one reference location is indicated as moving (S2=Yes), a check is performed for the corresponding reference location to see whether an update has been performed via system information (S4). S4 is optional. If each of one or both mobile reference locations has been updated via system information (S4=Yes), the UE will update the corresponding reference location based on the system information (e.g., via footfootInfo) (S5). If at least one of the one or both mobile reference locations has not been updated via system information (S4=No), or if S4 is omitted, the UE will autonomously update one or both reference locations as described above (S6). That is, the UE will calculate the interpolated position of the corresponding reference position based on the initial reference point, ephemeris, the time point when the initial reference point is valid, and the current time. The UE then evaluates CondEvent D1 to decide whether CHO can be performed using the ReferenceLocation obtained through the relevant steps in S3, S5 and S6 (S7).

[0070] Instead of, or in addition to, the conditional handover procedure described above, some example embodiments may be applied to a cell reselection procedure (RRC idle mode mobility procedure). In this case, the UE determines the distances to the reference locations of the cell on which the UE is camped (i.e., the serving cell) and the target cell, and uses these distances to decide whether to reselect the serving cell. For the cell reselection decision, the UE may autonomously update one or both reference locations, as in the case of conditional handover. Conditional handover and cell reselection are examples of mobility actions performed based on a decision made by the UE (mobility decision).

[0071] Figure 4 An apparatus according to an example embodiment is shown. The apparatus may be a terminal (eg, a UE or an IoT device) or a unit thereof. Figure 5A method according to an example embodiment is shown. Figure 4 The device can perform Figure 5 method, but not limited to this method. Figure 5 The method can be Figure 4 The present invention is performed by a device, but is not limited to being performed by the device.

[0072] The apparatus includes a receiving component 110, a checking component 120, an updating component 130, a determining component 140, a deciding component 150, and a prohibiting component 160. The receiving component 110, the checking component 120, the updating component 130, the determining component 140, the deciding component 150, and the prohibiting component 160 may be a receiving component, a checking component, an updating component, a determining component, a deciding component, and a prohibiting component, respectively. The receiving component 110, the checking component 120, the updating component 130, the determining component 140, the deciding component 150, and the prohibiting component 160 may be a receiver, a checker, an updater, a determiner, a decider, and a prohibitor, respectively. The component for receiving 110, the component for checking 120, the component for updating 130, the component for determining 140, the component for deciding 150, and the component for inhibiting 160 may be a receiving processor, an checking processor, an updating processor, a determining processor, a deciding processor, and an inhibiting processor.

[0073] The receiving means 110 receives an implicit or explicit dynamic mobility indication (S110). The dynamic mobility indication indicates whether a reference location is to be autonomously updated for use in a terminal's mobility decision. The reference location is defined relative to a satellite cell. The mobility decision may be, for example, a decision regarding conditional handover or cell reselection.

[0074] The means 120 for checking checks whether the dynamic movement indication indicates that the location of the reference position is to be autonomously updated for mobility decision ( S120 ).

[0075] In response to checking that the dynamic mobility indication indicates that the location of the reference position is to be autonomously updated for use in mobility determination (S120 = Yes), updating component 130 updates the location of the reference position (S130). Optionally, updating component 130 updates the location of the reference position based on satellite ephemeris, an initial location of the reference position, a time point when the reference position was at the initial location, and the current time. Alternatively, updating component 130 updates the location of the reference position by interpolation based on the initial location of the reference position, a first time point when the reference position was at the initial location, another location of the reference position, a second time point when the reference position was at the other location, and the current time. Alternatively, updating component 130 may combine the above two options to update the location of the reference position. The updated location of the reference position is indicated as a location on Earth.

[0076] The determining means 140 determines the distance between the estimated current location of the terminal and the interpolated location of the reference location of S130 (S140). Some exemplary embodiments include means for estimating the current location of the terminal to obtain the estimated current location, while other exemplary embodiments receive the estimated current location from another module or network. The estimated current location of the terminal is indicated as a location on the earth.

[0077] The component 150 for determining whether a condition for the terminal to perform a mobility action is satisfied (S150). The mobility decision is used to determine whether the mobility action can be performed. For example, if the mobility decision includes a decision regarding conditional handover, the mobility action includes conditional handover. For another example, if the mobility decision includes a decision regarding cell reselection, the mobility action includes cell reselection. The condition is satisfied if at least one of the following applies: - The distance at S140 is greater than a first threshold, and the mobility action is away from the cell (e.g., conditional handover from the cell or reselection from the cell to another cell); or - The distance of S140 is less than a second threshold, and the mobility action is towards the cell (eg, conditional handover towards the cell or reselection from another cell to the cell).

[0078] In response to determining that the condition is not satisfied (S150 = No), the prohibiting component 160 prohibits the terminal from performing the mobility action (S160). In some example embodiments, if the condition is satisfied (S150 = Yes), the apparatus may allow the terminal to perform the mobility action, provided that another condition does not prevent the performance of the mobility action.

[0079] Figure 6An apparatus according to an example embodiment is shown. The apparatus may be a base station (e.g., a gNB or eNB) or a unit thereof. The base station may be located on a satellite or relayed from Earth, i.e., the satellite performs amplification and forwarding operations on the signal between the UE and the base station. Figure 7 A method according to an example embodiment is shown. Figure 6 The device can perform Figure 7 method, but not limited to this method. Figure 7 The method can be Figure 6 The present invention is performed by a device, but is not limited to being performed by the device.

[0080] The apparatus comprises means for indicating 210. The means for indicating 210 may be an indication. The means for indicating 210 may be an indicator. The means for indicating 210 may be an indication processor.

[0081] The indicating component 210 instructs the terminal to autonomously calculate an updated location for a reference position of a satellite cell (S210). As an option, the indicating component 210 instructs the terminal to autonomously calculate the updated location for the reference position based on the satellite's ephemeris, the initial location of the reference point, the time point at which the reference point was at the initial location, and the current time. As another option, the indicating component 210 instructs the terminal to autonomously calculate the updated location for the reference position by interpolation based on the initial location of the reference position, the first time point at which the reference position was at the initial location, another location of the reference position, the second time point at which the reference position was at the other location, and the current time. As yet another option, the indicating component 210 may combine the above two options to instruct the terminal to update the location for the reference position. For example, the indicating component 210 may instruct the terminal to autonomously calculate the updated location for the reference position for use in UE mobility decisions, such as those regarding conditional handover or cell reselection. The reference position is defined relative to the cell.

[0082] Figure 8 1 shows an apparatus according to an example embodiment. The apparatus comprises at least one processor 810 and at least one memory 820 storing instructions, which instructions, when executed by the at least one processor 810, cause the apparatus to at least perform the following at least one of the following diagrams ( Figure 5 or Figure 7 ) and its related description methods.

[0083] Some example embodiments are described with respect to 5G networks. However, the present invention is not limited to 5G. It can also be used in other NTN communication networks, for example, previous or future 3GPP networks such as 4G, 6G, or 7G.

[0084] A piece of information can be transferred from one entity to another via one or more messages. Each message can include further (different) information.

[0085] The names of network elements, network functions, protocols, and methods are based on current standards. In other versions or other technologies, the names of these network elements and / or network functions and / or protocols and / or methods may be different, as long as they provide the corresponding functions. The same applies to terminals.

[0086] Unless otherwise specified or the context clearly dictates otherwise, when two entities are described as different, it means that they perform different functions. This does not necessarily mean that they are based on different hardware. In other words, each entity described in this specification can be based on different hardware, or some or all entities can be based on the same hardware. This does not necessarily mean that they are based on different software. In other words, each entity described in this specification can be based on different software, or some or all entities can be based on the same software. Each entity described in this specification can be deployed in the cloud.

[0087] From the above description, it should be apparent that example embodiments provide, for example, a terminal (e.g., UE, MTC device, etc.) of a radio access network or a component thereof, an apparatus embodying the same, a method of controlling and / or operating the same, a computer program for controlling and / or operating the same, and a medium carrying such a computer program and forming a computer program product. From the above description, it should be apparent that example embodiments provide, for example, a satellite or a component thereof, an apparatus embodying the same, a method of controlling and / or operating the same, a computer program for controlling and / or operating the same, and a medium carrying such a computer program and forming a computer program product.

[0088] Implementations of any of the above blocks, devices, systems, techniques, or methods include, but are not limited to, implementations in hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof. Each entity described in this specification may be embodied in the cloud.

[0089] It should be understood that the above is presently considered to be the preferred exemplary embodiment. However, it should be noted that the description of the preferred exemplary embodiment is given by way of example only and that various modifications may be made without departing from the scope of the invention as defined by the appended claims.

[0090] Unless otherwise specified, the terms "first X" and "second X" include options where "first X" is the same as "second X" and where "first X" is different from "second X". As used herein, "at least one of: " and "at least one of " and similar expressions (wherein a list of two or more elements is linked by "and" or "or") mean at least any one element, or at least any two or more elements, or at least all elements.

Claims

1. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the one or more processors, cause the apparatus to at least: receiving an implicit or explicit first dynamic mobility indication indicating whether a location of a first reference position is to be autonomously updated for use in mobility decisions of the terminal, wherein the first reference position is defined relative to a first cell of a first satellite; checking whether the first dynamic mobility indication indicates that the location of the first reference position is to be autonomously updated for use in the mobility decision; in response to checking that the first dynamic mobility indication indicates that the location of the first reference location is to be autonomously updated for the mobility determination, updating the location of the first reference location based on one of the ephemeris of the first satellite and another location of the first reference location together with a second point in time at which the first reference location was at the other location, an initial location of the first reference location, a first point in time at which the first reference location was at the initial location, and a current time; determining a first distance between a current location of the terminal and the updated location of the first reference location; determining whether a first condition for performing a mobility action by the terminal is satisfied; In response to determining that the first condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the first reference position and the current location of the terminal are indicated as locations on Earth; The mobility decision is used to determine whether the mobility action can be performed; The first condition is met if at least one of the following applies: - the first distance is greater than a first threshold, and the mobility action is to move away from the first cell; or - The first distance is less than a second threshold, and the mobility action is towards the first cell.

2. The device according to claim 1, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: receiving an implicit or explicit second dynamic mobility indication indicating whether a location of a second reference position is to be autonomously updated for use in the mobility decision, wherein the second reference position is defined relative to a second cell of a second satellite; checking whether the second dynamic mobility indication indicates that the location of the second reference position is to be autonomously updated for use in the mobility decision; in response to checking that the second dynamic mobility indication indicates that the location of the second reference location is to be autonomously updated for making the mobility determination, updating the location of the second reference location based on one of the ephemeris of the second satellite and another location of the second reference location together with a fourth point in time when the second reference location was at the another location, an initial location of the second reference location, a third point in time when the second reference location was at the initial location, and a current time; determining a second distance between the estimated current location of the terminal and the updated position of the second reference location; determining whether a second condition for performing the mobility action by the terminal is satisfied; In response to determining that the second condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the second reference position is indicated as a location on Earth; If the mobility action is to move away from the first cell, then if the second distance is less than a third threshold, the second condition is satisfied; If the mobility action is towards the first cell, the second condition is met if the second distance is greater than a fourth threshold.

3. The device according to any one of claims 1 and 2, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: determining whether an absolute value of a difference between the first distance and the first threshold is less than a fifth threshold; AND at least one of the following: - in response to determining that the absolute value of the difference between the first distance and the first threshold is less than a fifth threshold, calculating the updated location of the first reference position with a first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, calculating the updated location of the first reference position with a second frequency; or - in response to checking that the absolute value of the difference between the first distance and the first threshold is smaller than the fifth threshold, estimating the current location of the terminal at the first frequency, and in response to checking that the absolute value of the difference between the first distance and the first threshold is not smaller than the fifth threshold, estimating the current location of the terminal at the second frequency; and The instructions, when executed by the at least one processor, cause the apparatus to: in response to checking that the absolute value of the difference between the first distance and the first threshold is smaller than the fifth threshold, deciding whether the first condition for performing the mobility action by the terminal is satisfied at the first frequency; In response to checking that the absolute value of the difference between the first distance and the first threshold is not less than the fifth threshold, deciding whether the first condition for performing the mobility action by the terminal is satisfied at the second frequency; wherein, The second frequency is lower than the first frequency.

4. The device according to any one of claims 1 to 3, wherein The instructions, when executed by the at least one processor, cause the apparatus to: The implicit first dynamic movement indication is received by at least one of: - an indication of an end time for determining coverage availability of the first cell is not configured; - monitoring said first cell on a frequency layer different from each of the one or more terrestrial frequency bands according to a stored frequency table.

5. The device according to any one of claims 1 to 4, wherein At least one of the following applies: - the mobility decision comprises a decision regarding a conditional handover, and the mobility action comprises the conditional handover; or - the mobility decision comprises a decision regarding cell reselection, and the mobility action comprises the cell reselection.

6. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform the following operations: instructing the terminal to autonomously calculate an updated location of the reference position of the cell of the satellite based on one of the ephemeris of the satellite and another location of the reference position together with a second time point at which the reference position of the cell of the satellite is at another location, an initial location of the reference point, a first time point at which the reference point is at the initial location, and a current time, wherein The reference position is defined relative to the cell.

7. The device according to claim 6, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: The initial location of the reference position of the cell is provided to the terminal.

8. The device according to claim 7, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: An indication is provided to the terminal that the reference location is at the first point in time at the initial location.

9. The device according to any one of claims 6 to 8, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: At least one of the ephemeris of the satellite and the another location of the reference position of the cell is provided to the terminal.

10. The device according to claim 9, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: An indication is provided to the terminal that the reference location is at the second point in time at the other location.

11. The device according to any one of claims 6 to 10, wherein The instructions, when executed by the at least one processor, further cause the apparatus to: If the distance between the autonomous update location of the reference point and the current location of the terminal is out of range, the terminal is prohibited from performing a mobility action.

12. The device according to claim 11, wherein The mobility action may include at least one of conditional handover and cell reselection.

13. A method comprising: receiving an implicit or explicit first dynamic mobility indication indicating whether a location of a first reference position is to be autonomously updated for use in mobility decisions of the terminal, wherein the first reference position is defined relative to a first cell of a first satellite; checking whether the first dynamic mobility indication indicates that the location of the first reference position is to be autonomously updated for use in the mobility decision; in response to checking that the first dynamic mobility indication indicates that the location of the first reference location is to be autonomously updated for the mobility determination, updating the location of the first reference location based on one of the ephemeris of the first satellite and another location of the first reference location together with a second point in time at which the first reference location was at the other location, an initial location of the first reference location, a first point in time at which the first reference location was at the initial location, and a current time; determining a first distance between a current location of the terminal and the updated location of the first reference location; determining whether a first condition for performing a mobility action by the terminal is satisfied; In response to determining that the first condition is not satisfied, prohibiting the terminal from performing the mobility action, wherein The updated location of the first reference location and the current location of the terminal are indicated as locations on Earth; The mobility decision is used to determine whether the mobility action can be performed; The first condition is met if at least one of the following applies: - the first distance is greater than a first threshold, and the mobility action is to move away from the first cell; or - The first distance is less than a second threshold, and the mobility action is towards the first cell.

14. A method comprising: instructing the terminal to autonomously calculate an updated location of the reference position of the cell of the satellite based on one of the ephemeris of the satellite and another location of the reference position together with a second time point at which the reference position of the cell of the satellite is at another location, an initial location of the reference point, a first time point at which the reference point is at the initial location, and a current time, wherein The reference position is defined relative to the cell.

15. A computer program product comprising a set of instructions which, when executed on a device, are configured to cause the device to perform the method according to claim 13.

16. A computer program product comprising a set of instructions which, when executed on a device, are configured to cause the device to perform the method according to claim 14.

Images