Ue-specific time-based offset for serving cell coverage end

Abstract

Example embodiments provide a procedure of controlling cell measurements performed by a client node in a non-terrestrial network. An apparatus is configured to: receive parameters from a base station providing a serving cell to a client node in a non-terrestrial network, the parameters including at least one of a reference location of the serving cell, an indication of a direction of movement of the serving cell, or a cell radius parameter of the serving cell; obtaining one or more offset parameters for at least one of time or distance relative to the reference position; determining cell coverage based on the reference position and the cell radius parameter; determining a measurement relaxation area within the cell coverage based on at least one of the one or more offset parameters and the parameters received from the base station; obtaining the current position of the client node; determining when the client node is located within the measurement relaxation area; and determining that at least some of the mobility measurements are not performed by the client node when the client node is located within the measurement relaxation area.

Description

Technical Field

[0001] This application generally relates to information technology. Specifically, some example embodiments of this application relate to apparatuses configured to determine a time-based offset for service cell coverage end, and more specifically, to a time-based offset for an earth mobile cell in a non-terrestrial network. Background Art

[0002] A non-terrestrial network (NTN) refers to a network or network segment that uses airborne or spaceborne vehicles for transmission.

[0003] In an NTN system, a 5G base station (gNB) can be deployed, for example, on a satellite to provide communication coverage over a very large area where a cellular network may not reach. The NTN system can be used, for example, to globally connect IoT devices and provide personal communication in remote areas and disaster relief.

[0004] However, the movement of both the satellite and the devices coupled to the satellite communication poses challenges to communication based on the NTN system. Summary of the Invention

[0005] This Summary of the Invention is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary of the Invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0006] Example embodiments can enable controlling mobility measurements and triggering mobility events based on a measurement relaxation region determined by a client node. This can be achieved by the features of the independent claims. Other implementations are provided in the dependent claims, the description, and the drawings.

[0007] According to a first aspect, an apparatus may include: at least one processor; and at least one memory including instructions that, when executed by the at least one processor, cause the apparatus to at least: receive parameters from a base station that provides a service cell to a client node in a non-terrestrial network, the parameters including at least one of the following: a reference position of the service cell, an indication of a movement direction of the service cell, or a cell radius parameter of the service cell; obtain one or more offset parameters for at least one of time or distance relative to the reference position; determine cell coverage based on the reference position and the cell radius parameter; determine a measurement relaxation region within the cell coverage based on the one or more offset parameters and at least one of the parameters received from the base station; obtain a current position of the client node; determine when the client node is within the measurement relaxation region; and when the client node is within the measurement relaxation region, determine that at least some of the mobility measurements in the mobility measurements are not performed by the client node.

[0008] According to an example embodiment of the first aspect, one or more offset parameters are received from a base station or determined by the device.

[0009] According to an example embodiment of the first aspect, at least one memory includes instructions that, when executed by at least one processor, cause the device to: determine a second reference position of the serving cell based on one or more offset parameters and an indication of the direction of movement; determine a second cell coverage based on the second reference position and a cell radius parameter; and determine that the measurement relaxation region includes at least a partially overlapping region of the second cell coverage and the first cell coverage.

[0010] According to an example embodiment of the first aspect, at least one memory further includes instructions that, when executed by at least one processor, cause the device to: obtain a second cell radius parameter for the serving cell; determine a second reference position of the serving cell based on one or more offset parameters and an indication of the direction of movement; determine a second cell coverage based on the second reference position and the second cell radius parameter; and determine the measurement relaxation region based on the overlapping region of the second cell coverage and the first cell coverage.

[0011] According to an example embodiment of the first aspect, the indication of the direction of movement includes satellite ephemeris; and at least one memory further includes instructions that, when executed by at least one processor, cause the device to: determine the second reference position based on the satellite ephemeris and one or more offset parameters.

[0012] According to an example embodiment of the first aspect, one or more offset parameters include an array of time or distance parameters representing different distances from a first reference position; and at least one memory includes instructions that, when executed by at least one processor, cause the device to: determine a trailing edge of the measurement relaxation region in the direction of movement extending across the first cell coverage relative to the direction of movement perpendicular to the serving cell based on the array; and wherein the measurement relaxation region includes the portion of the first cell coverage defined by the trailing edge.

[0013] According to an example embodiment of the first aspect, one or more offset parameters include an array of distances associated with a plurality of reference positions within the serving cell; and at least one memory includes instructions that, when executed by at least one processor, cause the device to: determine a trailing edge of the measurement relaxation region in the direction of movement extending across the first cell coverage relative to the direction of movement perpendicular to the serving cell based on the array; and wherein the measurement relaxation region includes the portion of the first cell coverage defined by the trailing edge.

[0014] According to an example embodiment of the first aspect, at least one memory further includes instructions that, when executed by at least one processor, cause the apparatus to: determine a measurement area based on coverage of a first cell not included in a measurement relaxation area; determine when a client node is located within the measurement area; and perform a mobility measurement when the client node is located within the measurement area.

[0015] According to an example embodiment of the first aspect, at least one memory further includes instructions that, when executed by at least one processor, cause the apparatus to: compare a distance between a trailing edge of a moving direction of a measurement relaxation area relative to a serving cell and the client node with a predefined threshold; and perform a mobility measurement when the distance between the trailing edge and the client node is less than the predefined threshold.

[0016] According to an example embodiment of the first aspect, an indication of a moving direction of a serving cell includes satellite ephemeris; and at least one memory further includes instructions that, when executed by at least one processor, cause the apparatus to: estimate a time when the client node is located before a trailing edge of a measurement relaxation area relative to the moving direction based on a current position of the client node and the satellite ephemeris; set a timer based on the estimated time; and start a mobility measurement based on expiration of the timer.

[0017] According to an example embodiment of the first aspect, an indication of a moving direction of a serving cell includes satellite ephemeris; and at least one memory further includes instructions that, when executed by at least one processor, cause the apparatus to: estimate a time point when the client node is located at a trailing edge of a measurement relaxation area relative to the moving direction based on a current position of the client node and the satellite ephemeris; and perform a mobility measurement at the estimated time point.

[0018] According to a second aspect, an apparatus may include: at least one processor; and at least one memory including instructions that, when executed by at least one processor, cause the apparatus to at least: send to a client node parameters related to a base station providing a serving cell to the client node in a non-terrestrial network, the parameters including at least one or more offset parameters of at least one of a reference position of the serving cell and a time for a distance.

[0019] According to an example embodiment of the second aspect, one or more offset parameters include at least one of the following: an array of time or distance parameters representing different distances from a first reference position, an array of time or distance parameters representing different distances from the first reference position and positioned between 0 degrees and 180 degrees relative to an axis perpendicular to the moving direction, an array of distances associated with multiple reference positions within the serving cell, or an array of distances associated with multiple reference positions within the serving cell on an axis perpendicular to the moving direction.

[0020] According to a third aspect, a method may include: receiving, from a base station that provides a serving cell to a client node in a non-terrestrial network, a parameter that includes at least one of the following: a reference location of the serving cell, an indication of a moving direction of the serving cell, and a cell radius parameter of the serving cell; obtaining one or more offset parameters for at least one of time or distance relative to the reference location; determining cell coverage based on the reference location and the cell radius parameter; determining a measurement relaxation region within the cell coverage based on the one or more offset parameters and at least one parameter received from the base station; obtaining a current location of the client node; determining when the client node is within the measurement relaxation region; and when the client node is within the measurement relaxation region, determining that at least some of the mobility measurements in the mobility measurements are not performed by the client node.

[0021] According to an example embodiment of the third aspect, the one or more offset parameters are received from the base station or determined by the client node.

[0022] According to an example embodiment of the third aspect, the method includes: determining a second reference location of the serving cell based on the one or more offset parameters and the indication of the moving direction; determining a second cell coverage based on the second reference location and the cell radius parameter; and determining that the measurement relaxation region includes at least a partially overlapping region of the second cell coverage and the first cell coverage.

[0023] According to an example embodiment of the third aspect, the method includes: obtaining a second cell radius parameter for the serving cell; determining a second reference location of the serving cell based on the one or more offset parameters and the indication of the moving direction; determining a second cell coverage based on the second reference location and the second cell radius parameter; and determining the measurement relaxation region based on an overlapping region of the second cell coverage and the first cell coverage.

[0024] According to an example embodiment of the third aspect, the indication of the moving direction includes satellite ephemeris; and wherein the method further includes: determining the second reference location based on the satellite ephemeris and the one or more offset parameters.

[0025] According to an example embodiment of the third aspect, the one or more offset parameters include an array of time or distance parameters representing different distances from the first reference location; and the method further includes: determining, based on the array, a trailing edge of the moving direction of the measurement relaxation region extending across the first cell coverage perpendicular to the moving direction of the serving cell; and wherein the measurement relaxation region includes a portion of the first cell coverage defined by the trailing edge.

[0026] According to an example embodiment of the third aspect, one or more offset parameters include an array of distances associated with a plurality of reference positions within a serving cell; and the method further includes: based on the array, determining a trailing edge of a measurement relaxation region with respect to a direction of movement that extends across a first cell coverage perpendicular to the direction of movement of the serving cell; and wherein the measurement relaxation region includes a portion of the first cell coverage defined by the trailing edge.

[0027] According to an example embodiment of the third aspect, the method includes: determining a measurement region based on a first cell coverage not included in the measurement relaxation region; determining when a client node is located within the measurement region; and performing a mobility measurement when the client node is located within the measurement region.

[0028] According to an example embodiment of the third aspect, the method includes: comparing a distance between a trailing edge of the measurement relaxation region with respect to a direction of movement of the serving cell and the client node with a predefined threshold; and performing a mobility measurement when the distance between the trailing edge and the client node is less than the predefined threshold.

[0029] According to an example embodiment of the third aspect, an indication of the direction of movement of the serving cell includes satellite ephemeris; and the method includes: estimating a time when the client node is located before a trailing edge of the measurement relaxation region with respect to the direction of movement based on a current position of the client node and the satellite ephemeris; setting a timer based on the estimated time; and starting a mobility measurement based on expiration of the timer.

[0030] According to an example embodiment of the third aspect, an indication of the direction of movement of the serving cell includes satellite ephemeris; and wherein the method includes: estimating a time point when the client node is located at a trailing edge of the measurement relaxation region with respect to the direction of movement based on a current position of the client node and the satellite ephemeris; and performing a mobility measurement at the estimated time point.

[0031] According to a fourth aspect, a method may include: sending to a client node parameters related to a base station that provides a serving cell to the client node in a non-terrestrial network, the parameters including at least one of a reference position of the serving cell and one or more offset parameters for at least one of time for a distance.

[0032] According to an example embodiment of the fourth aspect, one or more offset parameters include at least one of the following: an array of time or distance parameters representing different distances from a first reference position, an array of time or distance parameters representing different distances from the first reference position and positioned between 0 degrees and 180 degrees with respect to an axis perpendicular to the direction of movement, an array of distances associated with a plurality of reference positions within the serving cell, or an array of distances associated with a plurality of reference positions within the serving cell on an axis perpendicular to the direction of movement.

[0033] According to a fifth aspect, a computer program, when executed by a processor, may be configured to cause a device to at least perform the following operations: receive parameters from a base station that provides a serving cell to a client node in a non-terrestrial network, the parameters including at least one of the following: a reference position of the serving cell, an indication of a moving direction of the serving cell, and a cell radius parameter of the serving cell; obtain one or more offset parameters for at least one of time or distance relative to the reference position; determine a cell coverage based on the reference position and the cell radius parameter; determine a measurement relaxation area within the cell coverage based on the one or more offset parameters and at least one parameter received from the base station; obtain a current position of the client node; determine when the client node is within the measurement relaxation area; and when the client node is within the measurement relaxation area, determine that at least some of the mobility measurements in the mobility measurements are not performed by the client node. The computer program may further include instructions for causing the device to perform any embodiment of the method of the third aspect.

[0034] According to a sixth aspect, a device may include components for the following operations: receive parameters from a base station that provides a serving cell to a client node in a non-terrestrial network, the parameters including at least one of the following: a reference position of the serving cell, an indication of a moving direction of the serving cell, and a cell radius parameter of the serving cell; obtain one or more offset parameters for at least one of time or distance relative to the reference position; determine a cell coverage based on the reference position and the cell radius parameter; determine a measurement relaxation area within the cell coverage based on the one or more offset parameters and at least one parameter received from the base station; obtain a current position of the client node; determine when the client node is within the measurement relaxation area; and when the client node is within the measurement relaxation area, determine that at least some of the mobility measurements in the mobility measurements are not performed by the client node. The device may further include components for performing any exemplary embodiment of the method of the third aspect.

[0035] According to a seventh aspect, a computer program may include instructions that cause a device to at least perform the following operations: send parameters related to a base station that provides a serving cell to a client node in a non-terrestrial network to the client node, the parameters including at least one of the reference position of the serving cell and one or more offset parameters for time or distance. The computer program may further include instructions for causing the device to perform any exemplary embodiment of the method of the fourth aspect.

[0036] According to an eighth aspect, an apparatus may include components for: sending to a client node parameters related to a base station that provides a serving cell to the client node in a non-terrestrial network, the parameters including at least one of a reference location of the serving cell and one or more offset parameters for time with respect to distance. The apparatus may further include components for performing any of the example embodiments of the method of the fourth aspect.

[0037] Many attendant features will be more readily understood as they become better understood by reference to the following detailed description, which is to be considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are included to provide a further understanding of example embodiments and constitute a part of this specification, illustrate example embodiments and together with the description help to explain the example embodiments. In the figures:

[0039] Figure 1 An example of a non-terrestrial network including at least one network node and at least one client node according to an example embodiment is shown.

[0040] Figure 2 An example of a UE configured with different t serving parameters in an earth mobile cell is shown;

[0041] Figure 3 An example of a UE configured with distance-based events is shown;

[0042] Figure 4 An example of a measurement relaxation region calculated by a UE according to an example embodiment is shown;

[0043] Figure 5 An example of a distance array provided by a serving cell to a UE according to an example embodiment is shown;

[0044] Figure 6 An example of an apparatus configured to practice one or more example embodiments is shown;

[0045] Figure 7 An example of a sequence diagram of messages between a UE, a serving cell, and a target cell according to an example embodiment to determine a UE-specific time-based offset for serving cell coverage end is shown;

[0046] Figure 8 An example of a UE entering a serving cell from different points according to an example embodiment is shown;

[0047] Figure 9 An example of a method for controlling mobility measurements in an NTN network according to an example embodiment is shown; and

[0048] Figure 10Shows an example of a method for assisting in controlling mobility measurements in an NTN network according to an example embodiment.

[0049] In the drawings, the same reference numerals are used to denote the same components. Detailed implementation

[0050] Reference will now be made in detail to example embodiments, which are illustrated in the accompanying drawings. The detailed description provided below in conjunction with the accompanying drawings is intended as a description of the present example and is not intended to represent the only form in which the present example can be constructed or utilized. This specification sets forth the functions of the example and the possible sequences of operations for constructing and operating the example. However, the same or equivalent functions and sequences can be achieved by different examples.

[0051] Figure 1 Shows an example of a non-terrestrial network including at least one network node and at least one client node according to an example embodiment.

[0052] NTN 100 may include one or more base stations, represented by gNB 102. gNB 102 may be installed on an airborne vehicle or a spaceborne vehicle. The spaceborne vehicle may include, for example, a satellite in low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), or highly elliptical orbit (HEO). A satellite including a base station may be referred to as a communication satellite. The communication satellite may be implemented as a regenerative (with on-board processing by the gNB) payload. NTN 100 may also include other base stations, such as one or more gNBs located on the ground plane. In this case, the satellite may be implemented as a transparent payload-based satellite and configured to act as an analog radio frequency repeater for a base station located on the ground. For example, the satellite may be configured to relay and / or amplify and forward signals received from a gNB, for example, between a satellite gateway 106 and a data network 108. Thus, depending on the implementation, the satellite (or other airborne / spaceborne vehicle) may be configured to act as a relay node or a base station. The gNB 102 on the satellite or on the ground may be configured to generate a number of beams over a given service area defined by its field of view 110. The footprint 112 of the beam may refer to the ground area covered by the transponder of the communication satellite to provide cell coverage. Cell coverage may refer to the geographical area covered by the network. The field of view 110 of the satellite may depend on the on-board antenna pattern and the minimum elevation angle. A gNB is generally referred to as a network node or network device. Although depicted as a single device, the network node may not be an independent device but, for example, a distributed computing system coupled to a remote radio head.

[0053] NTN 100 may also include one or more client nodes, which may also be referred to as user nodes or UEs. For example, network 100 may include UE 104. UE 104 may be a terrestrial UE located at the ground plane. The UE may include, for example, a mobile phone or an IoT device. UE 104 may communicate with one or more base stations via a wireless radio channel. The communication between UE 104 and gNB102 may be two-way. Thus, any device may be configured to operate as a transmitter and / or a receiver. UE 104 may be served by gNB 102 within the target service area shown by coverage area 112 within the field of view 110.

[0054] NTN 100 may include one or more satellite gateways 106, which may be configured to connect NTN 100 to data network 108 via a core network. The satellite gateway 106 may also be referred to as an NTN gateway. The NTN gateway may be configured to connect the satellite to the gNB (in the case of a transparent payload) or directly to the core network (in the case of a regenerative payload). The satellite gateway 106 may be configured to transmit data from the satellite to the data network 108 (such as a local area network) and transmit data from the data network 108 to the satellite. The gNB 102 may be configured to communicate with the satellite gateway 106 via a communication interface (e.g., a control plane interface or a user plane interface NG-C / U). NTN 100 may include a feeder link or a radio link between the satellite gateway 106 and the satellite / gNB 102, and a service link or a radio link between the UE 104 and the satellite / gNB 102.

[0055] The NTN network 100 may be configured, for example, according to the fifth-generation digital cellular communication network defined by the Third Generation Partnership Project (3GPP). In one example, NTN 100 may operate according to 3GPP 5G-NR. In one example, NTN100 may operate according to 3GPP IoT on NTN, which may be based on NB-IoT (Narrowband IoT) and eMTC (Enhanced Machine-Type Communication) that support NTN. However, it should be understood that the example embodiments presented herein are not limited to this example network, but may be applied to any current or future wireless or wired communication network or a combination thereof, such as other types of cellular networks, short-range wireless networks, broadcast or multicast networks, etc.

[0056] As described above, there are different types of satellite orbits available for NTN access, including Low Earth Orbit (LEO) satellites. LEO satellites can be configured to orbit at approximately 600 km above the Earth. It can be assumed that the diameter of the typical beam coverage area for LEO satellites ranges between 50 - 1000 km. Thus, a single LEO satellite can cover a very large area on the Earth that may include multiple countries. Due to being at low altitude, LEO satellites move relative to the Earth at a speed of approximately 7.5 km / s.

[0057] In 3GPP, Earth Fixed Cells (EFCs) and Earth Moving Cells (EMCs) can be considered. The former (EFC) requires the satellite to continuously adjust the satellite beam pointing direction to fix the NR (New Radio) cell and NR beam to a specific point on the Earth. The latter option (EMC) requires a fixed satellite beam pointing direction, so the coverage area of the beam (i.e., the NR cell) moves on the Earth. In EMC - based NTN, the mobility is mainly due to satellite movement as the satellite moves much faster than the UEs on the ground.

[0058] In an NTN system, the base station can be configured to broadcast parameters called t - service as part of the serving cell information. The t - service parameters are cell - specific and are common to all UEs in the same cell. The t - service parameters are designed for EFCs, where the value of the t - service parameter indicates the time when the EFC will stop serving its currently covered area.

[0059] For EMC, depending on the position of the UE within the cell, the UE can have different cell service durations. Thus, the stop - service time of the UE's cell (i.e., t - service) can vary for each UE. Different from quasi - Earth - fixed cells, the common t - service in Earth - moving cells may not be accurate and difficult to use because the remaining time will depend on the relative position of the UE in the moving cell. Figure 2 An example of the problem is shown. Figure 2 Two UEs (104A, 104B) connected to serving cell 200 are shown. When serving cell 200 moves from top to bottom, UEs 104A, 104B enter the coverage area of target cell 202 at different times. If both UEs 104A, 104B are configured with a common t - service, the following problems occur:

[0060] Target cell measurement / CHO (Conditional Handover) execution may be initiated prematurely. This may increase UE power consumption, which can be critical for IoT (Internet of Things) UEs. Assuming that the stop - service time of serving cell 200 is less than the t - service value 206 of the second UE 104B, the second UE 104B may initiate measurements of target cell 202 prematurely.

[0061] Target cell measurement / CHO execution may also be initiated too late, which increases the likelihood of RLF (Radio Link Failure) and results in sub - optimal use of available resources. Assuming that the de - registration time of serving cell 200 is greater than the t - serving value 204 of the first UE 104A, the first UE 104A may initiate measurement of target cell 202 relatively late.

[0062] Moreover, in the case where the network can configure each UE with the correct timer, any movement of the UE will require the network to update the timer. This UE - specific signaling will result in a large signaling overhead. Even for a stationary UE, compared with the broadcast method for t - serving in EFC, UE - specific dedicated signaling may be required.

[0063] For time - based Conditional Handover (CHO), the UE can perform CHO during a specific time period. The execution conditions can be determined by the network, mainly based on the de - registration time of the serving cell and the registration time of the candidate cell. For quasi - geostationary cells, these time points are uniform and always valid for all UEs under the serving cell.

[0064] However, for mobile cells on Earth, depending on the location of the individual UE, there can be various de - registration times of the serving cell and registration times of the candidate cell for each UE. To support time - based CHO, the gNB will need to calculate the CHO execution time based on the current location reported by the UE and configure the CHO execution conditions to the UE. In this case, once the UE moves, the de - registration time of the serving cell and the registration time of the candidate cell will change, and the execution conditions may become invalid. Therefore, a CHO configuration update may be required, which will introduce signaling overhead, especially for high - speed UEs. Therefore, for the mobile cell on Earth scenario, enhancements may be needed to address the problem of invalid configurations caused by UE mobility to support time - based CHO.

[0065] For NTN - NTN cell reselection with mobile cells on Earth, it may be considered to provide the UE with parameters of the serving cell for the UE to estimate the de - registration time of the serving cell. These parameters of the serving cell may include satellite orbit parameters, location coordinates of the cell center, and / or cell coverage radius.

[0066] In addition to time - based solutions, the UE can also be configured with distance - based events. Although the network / UE may be able to predict cell movement, when the cell moves away, the UE may measure neighboring cells that do not cover the UE. Figure 3An example of the problem is shown. In this case, when the cells (e.g., serving cell 200, previous serving cell 300, and neighboring cell 302) move from top to bottom, UE 104 stays in the serving cell 200 until it reaches the cell edge (i.e., the bottom of the serving cell 200), where UE 104 is ready to switch to a new cell. Since distance-based events can be based on snapshot-based distance measurements, without considering any delta, when the cell moves away, the UE may trigger an undesired mobility event to a neighboring cell that meets the distance condition but may not cover the UE. Additionally, the UE may perform unnecessary radio measurements on these cells, resulting in suboptimal use of available resources and increased UE power consumption.

[0067] Furthermore, RSRP / RSRQ (Reference Signal Received Power / Quality) cell measurements can be used to determine the end of coverage of the serving cell. However, in NTN, due to the near-far effect, radio measurements may be unreliable due to the logarithmic behavior of propagation loss and long communication distances. This means that the received power difference between the cell edge and the cell center may be only a few decibels.

[0068] An object is to mitigate at least one of the above disadvantages. The present disclosure relates to a 5G New Radio Non-Terrestrial Network (NTN) base station / satellite (gNB) and a mobile device (UE) in a deployment with earth-moving cells. According to an example embodiment, a client node may be configured with satellite cell movement-related information and be configured to perform measurements when needed, e.g., according to satellite cell changes in a predicted time. The client node may be configured to obtain at least one time / distance offset parameter broadcast by a base station or determined by the client node. The client node may be configured to calculate, in combination with the known own position of the client node, satellite ephemeris, and the cell radius broadcast by the base station, when the client node will cross the cell edge in time. The client node may be configured to pause or relax handover measurements before the calculated time based on at least one time / distance offset parameter. In an example embodiment, an array of time / distance-based offset parameters specifies a distance measured from the cell center, which may define a rear boundary where measurement relaxation spans the entire width of the cell (i.e., perpendicular to the direction of cell movement). The UE may be configured to pause handover measurements until it crosses the rear boundary. Thus, the client node may be configured to consider the direction of cell movement in the interpretation of the broadcast or determined time / distance offset parameters.

[0069] Advantages of the example embodiments may include that a client node such as a UE spends less time and energy on measurements in an earth - moving cell. Additionally, signaling overhead is limited because the network can provide the UE with information to determine the pause / relaxation and / or start time of cell measurements for the serving / target cell, e.g., in an SIB (System Information Block), after which the UE can apply measurement relaxation based on its own location. This means that UE - specific configuration may not be required.

[0070] Figure 4 An example scenario is shown in which a UE 104 according to an example embodiment is configured to calculate a measurement relaxation region 402. The power consumption of the UE can be reduced because mobility measurements and the triggering of mobility events can be enhanced based on the calculated measurement relaxation region. The mobility measurements may include at least one of serving cell measurements and / or target / neighbor cell measurements. The target / neighbor cell measurements may include intra - frequency or inter - frequency or even inter - RAT measurements (referring to the frequency and RAT type of the serving cell).

[0071] In Figure 4 a serving cell 200 is the actual serving cell providing first - cell coverage for the UE 104, and an overlapping region between the serving cell 200 and a cell 400 providing second - cell coverage for the UE 104 shows a measurement relaxation region 402. The measurement relaxation region may be configured to include at least a partially overlapping region of the second - cell coverage and the first - cell coverage. The region of the serving cell 200 that does not overlap with the cell 400 or the measurement relaxation region 402 shows a measurement and / or handover region 404.

[0072] The UE 104 may be configured to calculate a time t - offset. The UE 104 may use the time t - offset to trigger serving / target cell measurements. Based on the time t - offset, the UE 104 may be configured to determine, for example, when the cell center of the serving cell 200 is at a new reference position.

[0073] The base station providing the serving cell 200 may be configured to broadcast data including a reference position (such as the serving cell center 408) and at least one offset parameter 406 (such as a time / distance offset (t - offset / d - offset)). The offset parameter may be determined by the base station, for example, based on UE capabilities or an estimate of a reasonable time for the UE to perform measurements. This data may be broadcast, for example, as part of an SIBX.

[0074] Alternatively, the base station providing the serving cell 200 to the UE 104 may be configured to provide an array of t / d - offset values 500 that represent different distances [d1, d2, d3, ···, dn, ···, dN) from the serving cell 200 reference position 502 (e.g., the serving cell center) to the boundary between the measurement / HO region 404 and the measurement relaxation region 402, asFigure 5 As shown. The boundary may correspond to the trailing edge 504 that measures the moving direction of the relaxation region relative to the serving cell.

[0075] The UE 104 may also be configured to obtain other serving cell parameters, such as satellite orbit parameters, satellite ephemeris, or cell radius parameters. The parameters may be received from the base station. Based on the satellite orbit parameters / ephemeris and t-offset, the UE 104 may be configured to calculate a new cell reference position. For example, the UE 104 may use at least one offset parameter 406 (e.g., t-offset = 2 s) to determine how far the cell center / reference position 408 of the serving cell 200 moves within 2 s (based on the ephemeris). For example, if the relative speed on the earth is 7.5 km / s, it will correspond to the cell center moving 15 km in the moving direction of the satellite. If at least one offset parameter 406 includes a distance, the UE 104 may be configured to determine the new cell reference position by directly shifting the serving cell center (reference position 408) according to the distance. The UE 104 may use the new cell reference position to estimate the measurement relaxation region 402. The new cell reference position may correspond to the center of the relaxation measurement region.

[0076] The UE 104 may be configured to use the cell radius parameter in combination with the new cell reference position (400) to determine the measurement relaxation region 402. The UE 104 may be configured to determine, for example, the first cell coverage associated with the serving cell 200 based on the received reference position and the cell radius parameter. The UE 104 may be configured to determine, for example, the second cell coverage associated with the cell 400 based on the new reference position and the cell radius parameter. Then, the UE 104 may determine the measurement relaxation region 402 based on the overlapping region of the first cell coverage and the second cell coverage.

[0077] In one embodiment, the UE 104 may be configured to receive different cell radius parameters from the base station for determining the measurement relaxation region 402. Therefore, the UE 104 may be configured to determine the first cell coverage and the second cell coverage based on the different cell radius parameters.

[0078] Alternatively, the array 500 of t / d-offset values may be used by the UE 104 to determine the measurement relaxation region 402 within the first cell coverage based on the trailing edge 504 of the indicated measurement relaxation region.

[0079] If the UE 104 is within the measurement relaxation region 402, the UE 104 may be configured to relax (target) cell measurements. The UE 104 may be configured to compare its own position obtained, for example, based on the GPS signal with the geographical area covered by the measurement relaxation region.

[0080] When reaching the trailing edge 504 of the measurement relaxation region 402 (i.e., the UE 104 is located in the region of the serving cell 200 that does not overlap with the cell 400), the UE 104 may be configured to perform target / serving cell measurements.

[0081] This disclosure is written in the context of an RRC-connected UE, but it can also be applied to measurement relaxation and cell reselection of, for example, RRC idle / inactive UEs.

[0082] Figure 6 An example of an apparatus 200 configured to practice one or more example embodiments is shown.

[0083] The apparatus 600 may include at least one processor 602. The at least one processor 602 may include, for example, one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a dedicated computer chip, etc.

[0084] The apparatus 600 may further include at least one memory 604. The memory 604 may be configured to store, for example, computer program code 606, such as operating system software and application software. The memory 604 may include one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination thereof. For example, the memory 604 may be embodied as a magnetic storage device (such as a hard disk drive, magnetic tape, etc.), a magneto-optical storage device, or a semiconductor memory (such as a mask ROM, a PROM (programmable ROM), an EPROM (erasable PROM), a flash ROM, a RAM (random access memory), etc.).

[0085] The apparatus 600 may also include one or more communication interfaces 608, which are configured to enable the apparatus 600 to send information to other apparatuses (such as the satellite / gNB 102 or the UE 104). The communication interface 608 may also be configured to enable the apparatus to receive information from other apparatuses (such as the satellite / gNB 102 or the UE 104). The communication interface 608 may be configured to provide at least one wireless radio connection, such as a 3GPP mobile broadband connection (e.g., 3G, 4G, 5G). However, the communication interface 608 may be configured to provide one or more other types of connections, such as a wireless local area network (WLAN) connection, such as standardized by the IEEE 802.11 series or the Wi-Fi Alliance; a short-range wireless network connection; a wired connection, such as a local area network (LAN) connection, a universal serial bus (USB) connection, or an optical network connection, etc.; or a wired Internet connection. The communication interface 608 may include or be configured to couple to at least one antenna to transmit and / or receive radio frequency signals. One or more of the various types of connections may also be implemented as separate communication interfaces, which may be coupled to or be configured to couple to multiple antennas.

[0086] The apparatus 600 may include, for example, a computing device, such as a base station, a network node, a server device, a client node, a mobile phone, a tablet computer, a laptop computer, an IoT device, etc. In one example, the apparatus 600 may include a vehicle, such as a satellite. Although the apparatus 600 is shown as a single device, it should be understood that, where applicable, the functions of the apparatus 600 may be distributed across multiple devices.

[0087] When the apparatus 600 is configured to implement some functions, some components and / or components of the apparatus 600 (e.g., at least one processor 602 and / or the memory 604) may be configured to implement that function. Additionally, when at least one processor 602 is configured to implement some functions, the function may be implemented using, for example, program code 606 included in the memory 604.

[0088] For example, the apparatus 600 may include a client node. The client node may be configured to trigger at least one of a serving cell or a target cell measurement based on a measurement criterion calculated by the client node according to an estimated movement of the serving cell. The client node may be configured to determine a measurement relaxation region based on a cell reference position and one or more time / distance offset parameters received from a base station providing the serving cell, and pause and / or start cell measurement based on the position of the client node relative to the measurement relaxation region. Alternatively, one or more time / distance offset parameters may be determined by the client node. Thus, when the time / distance offset parameters are determined by the client node, the client node can consider how fast it can perform the measurement, rather than using the broadcast offset parameters from the base station (which may be the same for all client nodes). In an embodiment, the base station may be configured to send multiple offset parameters to the client node, and the client node may be configured to select one or more of the multiple offset parameters based on the capabilities of the client node.

[0089] As another example, the apparatus 600 may include a network node and be configured to send to a client node parameters related to an earth mobile cell providing a serving cell, the parameters including at least one of a reference position of the serving cell and one or more offset parameters for at least one of time for distance. The parameters may further include at least one of the following: an indication of a movement direction of the serving cell or a cell radius parameter of the serving cell.

[0090] The functions described herein may be performed at least in part by one or more computer program product components such as software components. According to an embodiment, the apparatus 600 includes a processor or processor circuitry, such as a microcontroller, which when executed is configured by program code to perform embodiments of the operations and functions described. Alternatively or additionally, the functions described herein may be performed at least in part by one or more hardware logic components. Illustrative types of hardware logic components that may be used include, but are not limited to, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on a chip (SOCs), complex programmable logic devices (CPLDs), and graphics processing units (GPUs).

[0091] The apparatus 600 may include components for performing at least one of the methods described herein. In one example, the components include at least one processor 602 and at least one memory 604 including program code 606 configured to cause the apparatus 600 to perform the method when executed by the at least one processor 602.

[0092] Figure 7FIG. 0 shows an example message sequence diagram for signaling between UE 104, serving cell 200, and target cell 202 for determining a measurement relaxation region and evaluating time / distance / measurement-based CHO conditions.

[0093] At operation 700, UE 104 may be configured to obtain from a base station at least one t / d offset parameter associated with serving cell 200. For example, the base station / serving cell 200 may be configured to send to UE 104 a measurement configuration including a reference location of serving cell 200 and at least one t / d offset parameter. UE 104 may also be configured to obtain other serving cell parameters such as at least one of one or more cell radius parameters and satellite ephemeris.

[0094] Thereafter, UE 104 may be configured to determine when UE 104 may relax / suspend mobility measurements. At operation 702, UE 104 may be configured to calculate a second reference location for serving cell 200 based on at least one t / d offset. At operation 704, UE 104 may be configured to determine a measurement relaxation region. For example, UE 104 may be configured to determine a first cell coverage associated with the first reference location received at 700 and a second cell coverage associated with the second reference location determined at 702. For example, cell coverage may be determined based on the obtained serving cell parameters.

[0095] Alternatively, UE 104 may be configured to calculate the measurement relaxation region based on Figure 5 array 500 of distances as shown in FIG. In this case, the serving cell / base station may be configured to signal to UE 104 an array having N distances [d1, d2, ···, dn, ···, dN]. Considering the first reference location as the origin, the distance elements [d1, d2, ···, dn, ···, dN] may be configured to define a set of N vectors. The set of N vectors may be equally spaced between the vectors, for example. The vectors may be configured to be between 0 degrees and 180 degrees (where the point (0,0) of the local coordinate system is the first reference location). The vectors may be configured to point away from an axis perpendicular to the direction of movement. The trailing edge 504 of the measurement relaxation region may be drawn at the end of the vector, which may correspond to the edge of the second cell coverage. Yet another alternative would be to give an arrow with reference to the actual serving cell on the horizontal axis in the direction of movement relative to the serving cell (based on the first reference location and radius). The arrows may be equally spaced, for example, on a horizontal axis perpendicular to the direction of movement.

[0096] At operation 706, UE 104 may be configured to suspend or relax mobility measurements based on a measurement relaxation region. When mobility measurements are suspended, UE 104 may be configured to not measure either reference signal 708 received from serving cell 200 or reference signal 710 received from target cell 202. When mobility measurements are relaxed, UE 104 may be configured to perform mobility measurements at a reduced rate. Thus, when UE 104 is located within the measurement relaxation region, UE 104 may be configured to not perform any mobility measurements, or to relax and perform fewer mobility measurements, as compared to when UE 104 is located outside the measurement relaxation region but within the serving cell.

[0097] UE 104 may be configured to evaluate when it reaches the trailing edge of the measurement relaxation region and to resume intra-frequency / inter-frequency cell measurements at operation 712 after reaching the trailing edge of the measurement relaxation region. After UE 104 has started / triggered mobility measurements again at operation 712, UE 104 may be configured to measure subsequently received reference signals 708, 710.

[0098] Once UE 104 has estimated the measurement relaxation region, there are multiple options for UE 104 to determine when it has reached the trailing edge of the measurement relaxation region. In a location-based manner, UE 104 may be configured to trigger measurements based on a predefined distance threshold and the distance between its own location and the trailing edge. The predefined threshold may be determined by UE 104 or received from the serving cell. UE 104 may be configured to determine its current location, for example, using GNSS (such as GPS signals). When UE 104 is a fixed device, UE 104 may also be configured to determine its own location using a 3GPP-based positioning component or based on a hard-coded location. Alternatively, UE 104 may be configured to employ a time-based approach, where UE 104 may be configured to set a timer based on an estimated time when UE 104 will be at the trailing edge and to trigger mobility measurements based on the expiration of the timer, or to compare the absolute UTC time of UE 104 with a UTC time reference.

[0099] At operation 718, UE 104 may be configured to, after operation 712, notify serving cell 200 when target cell 202 meets predefined criteria for measurement reporting (MR) or conditional handover execution, based on received and measured reference signals 708, 710.

[0100] Thus, in an earth - moving cell, UE 104 can spend less time and energy on mobility measurements based on a measurement relaxation region determined by UE 104. Using the different methods described for estimating when a UE should perform mobility measurements and when location / time - based CHO conditions can be evaluated, UE - specific signaling may not be required.

[0101] Furthermore, the signaling overhead may be limited because the network can provide information for determining the measurement relaxation region in, for example, the SIB, after which UE 104 can apply measurement relaxation based on its own location, i.e., UE - specific configuration is not required.

[0102] The following examples provide some rough estimates to illustrate the advantages of the solution. Refer to Figure 8 Illustrative examples. The calculations of the examples can be based on:

[0103] Measurements of the signal references of the serving cell and the target cell can be performed by UEs entering the serving cell at a first location (UE 104A), a second location (UE 104B), and a third location (UE 104C) (e.g., every 20 ms).

[0104] The serving cell radius (Rc) 800 can be 25 km.

[0105] The satellite including the gNB can move at a speed of 7.8 km / s.

[0106] The parameters d_in 802 and t_in are the distance and time between the UE and the trailing edge of the measurement relaxation region 504, respectively.

[0107] The parameters d_out 804 and t_out are the distance and time between the trailing edge of the measurement relaxation region 504 and the geometric edge of the serving cell 200.

[0108] The first example considers an earth - moving cell flying over UE 104A, the center of which will pass through the UE location. This means that UE 104A can spend the maximum possible time in the serving cell 200 (i.e., 2 * 25 km / 7.8 km / s = 6.4 s).

[0109] UE 104A is able to identify a new detectable in - frequency cell within time T_identify. Assuming that the neighboring cell is synchronized with the serving cell 200 and discontinuous reception (DRX) is not configured, T_identify may not exceed 800 ms. The value 800 ms can be used as the maximum time t_out that UE 104A may need to leave the measurement relaxation region to identify and measure the upcoming target cell.

[0110] Given \(t_{out}=800\) ms and a satellite speed of \(7.8\) km / s, UE 104A can cover a distance \(d_{out}=6.24\) km outside the measurement relaxation area.

[0111] Considering \(R_c = 25\) km, then \(d_{in}=2\times R_c - d_{out}=43.76\) km. Thus, \(t_{in}=5.6\) s. Under these assumptions, in \(5.6\) s, compared with continuous measurement, UE 104A can save \(87.5\%\) of the energy used for measurement.

[0112] In the second example, it can be assumed that the average distance between two points in the circle is \(d_{avg}\approx R_c\times4 / \pi = 31.83\) km. Repeating the same calculations as in the first example for UE 104B, \(d_{in}=d_{avg}-d_{out}=25.6\) km, \(t_{in}=3.28\) s, and the energy saving is \(80\%\).

[0113] In the third example, it can be assumed that the worst distance (the time the UE is in the coverage area, i.e., the stay time, ToS = 1 s) applies to UE 104C, which is \(d_{min}=7.8\) km. Repeating the same calculations as in the first example for UE 104C, \(d_{in}=d_{min}-d_{out}=1.56\) km, \(t_{in}=0.2\) s, and the energy saving is \(20\%\).

[0114] Figure 9 An example of a method for controlling mobility measurements in an NTN network according to an example embodiment is shown. The method can be performed, for example, by a client node such as a UE.

[0115] At operation 900, the method can include: receiving, from a base station that provides a serving cell to the client node in a non-terrestrial network, a parameter that includes at least one of a reference position of the serving cell, an indication of the moving direction of the serving cell, and a cell radius parameter of the serving cell.

[0116] At operation 902, the method can include: obtaining one or more offset parameters of at least one of time or distance relative to the reference position. The one or more offset parameters can be determined, for example, by the UE or received from the base station.

[0117] At operation 904, the method can include: determining cell coverage based on the reference position and the cell radius parameter.

[0118] At operation 906, the method can include: determining a measurement relaxation area within the cell coverage based on the one or more offset parameters and at least one parameter received from the base station.

[0119] At operation 908, the method may include: obtaining the current location of a client node. For example, a device or client node may be configured to determine its own location based on, for example, GPS, a 3GPP-based positioning component, or a hard-coded location.

[0120] At operation 910, the method may include: determining when the client node is within a measurement relaxation region.

[0121] At operation 912, the method may include: suspending or relaxing mobility measurements when the client node is within the measurement relaxation region. Thus, the device may determine that at least some mobility measurements are not performed by the client node that would otherwise be performed when the client node is within the serving cell. For example, the client node may be configured to not perform any mobility measurements in the measurement relaxation region, or to perform measurements at a reduced rate (e.g., perform fewer measurements in the time domain) or measure fewer neighboring cells / frequency layers.

[0122] Figure 10 An example of a method for assisting in controlling mobility measurements in an NTN network according to an example embodiment is shown. The method may be performed, for example, by a base station such as a gNB.

[0123] At 1000, the method may include: sending to the client node parameters related to a base station providing a serving cell to the client node in a non-terrestrial network, the parameters including at least one of a reference location of the serving cell and one or more offset parameters for at least one of time for distance. The parameters may also include at least one of the following: an indication of the moving direction of the serving cell or a cell radius parameter of the serving cell.

[0124] Other features of the method directly result from the functions and parameters of the device, as described in the appended claims and throughout the specification, and thus are not repeated here. It should be noted that one or more operations of the method may be performed in a different order.

[0125] A device (e.g., a network node, a user node, or a client node) may be configured to perform or cause the performance of any aspect of the (multiple) methods described herein. Additionally, a computer program may include instructions for causing a device to perform any aspect of the methods described herein when executed. Additionally, a device may include components for performing any aspect of the (multiple) methods described herein. According to an example embodiment, the components include at least one processor and a memory including program code, the at least one memory and program code being configured to cause the performance of any aspect of the (multiple) methods when executed by the at least one processor.

[0126] Any range or device value given herein may be extended or altered without losing the desired effect. Moreover, unless expressly prohibited, any embodiment may be combined with another embodiment.

[0127] Although the subject matter has been described in language specific to structural features and / or acts, it is to be understood that the subject matter defined in the appended claims need not be limited to the specific features or acts described above. Rather, the above specific features and acts are disclosed as examples for implementing the claims, and other equivalent features and acts are intended to be within the scope of the claims.

[0128] It should be understood that the above benefits and advantages may relate to one embodiment or may relate to several embodiments. Embodiments are not limited to those that solve any or all of the stated problems or have any or all of the stated benefits and advantages. It will also be understood that a reference to "an" item may refer to one or more of those items.

[0129] The operations of the methods described herein may be performed in any suitable order or, where appropriate, simultaneously. Additionally, individual blocks may be deleted from any method without departing from the scope of the subject matter described herein. Aspects of any of the above embodiments may be combined with aspects of any of the other embodiments described to form additional embodiments without losing the desired effect.

[0130] The term "comprising" is used herein to mean including the identified method, block, or element, but such block or element does not comprise an exclusive list, and the method or apparatus may contain additional blocks or elements.

[0131] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) only hardware circuit implementations (such as implementations in only analog and / or digital circuitry), and (b) combinations of hardware circuits and software, such as, where applicable: (i) combinations of analog and / or digital hardware circuits with software / firmware, and (ii) any portions of hardware processors (including digital signal processors), software, and memory that work together to cause an apparatus (such as a mobile phone or server) to perform various functions, and (c) hardware circuits and / or processors, such as a microprocessor or a portion of a microprocessor, that require software (e.g., firmware) for operation but for which the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of the term in this application (including any claims).

[0132] As another example, as used in this application, the term circuitry also encompasses implementations that are only hardware circuitry, or a processor (or processors), or a portion of hardware circuitry or a processor and its (or their) attendant software and / or firmware. The term circuitry also encompasses (e.g., if applicable to a particular claim element) baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0133] It should be understood that the above description is given by way of example only, and that various modifications can be made by those skilled in the art. The above specification, examples, and data provide a complete description of the structure and use of the exemplary embodiments. Although the various embodiments have been described above with a certain degree of particularity or with reference to one or more individual embodiments, many changes can be made to the disclosed embodiments without departing from the scope of this specification.

Claims

1. An apparatus, comprising: at least one processor; and at least one memory including instructions which, when executed by the at least one processor, cause the apparatus to at least: receive parameters from a base station that provides a serving cell to a client node in a non-terrestrial network, the parameters including at least one of the following: a reference location of the serving cell, an indication of a moving direction of the serving cell, and a cell radius parameter of the serving cell; obtain one or more offset parameters for at least one of time or distance relative to the reference location; determine cell coverage based on the reference location and the cell radius parameter; determine a measurement relaxation region within the cell coverage based on the one or more offset parameters and at least one of the parameters received from the base station; obtain a current location of the client node; determine when the client node is within the measurement relaxation region; and when the client node is within the measurement relaxation region, determine that at least some of the mobility measurements in the mobility measurements are not performed by the client node.

2. The apparatus according to claim 1, wherein the one or more offset parameters are received from the base station or determined by the apparatus.

3. The apparatus according to claim 1 or 2, wherein the at least one memory includes instructions which, when executed by the at least one processor, cause the apparatus to: determine a second reference location of the serving cell based on the one or more offset parameters and the indication of the moving direction; determine a second cell coverage based on the second reference location and the cell radius parameter; and determine that the measurement relaxation region includes at least a partially overlapping region of the second cell coverage and the first cell coverage.

4. The apparatus according to claim 1 or 2, wherein the at least one memory further includes instructions which, when executed by the at least one processor, cause the apparatus to: obtain a second cell radius parameter for the serving cell; determine a second reference location of the serving cell based on the one or more offset parameters and the indication of the moving direction; determine a second cell coverage based on the second reference location and the second cell radius parameter; and determine the measurement relaxation region based on an overlapping region of the second cell coverage and the first cell coverage.

5. The apparatus according to claim 3 or 4, wherein the indication of the moving direction includes satellite ephemeris; and wherein the at least one memory further includes instructions which, when executed by the at least one processor, cause the apparatus to: determine the second reference location based on the satellite ephemeris and the one or more offset parameters.

6. The apparatus according to claim 1 or 2, wherein the one or more offset parameters include an array of time or distance parameters representing different distances from the first reference location; and the at least one memory includes instructions which, when executed by the at least one processor, cause the apparatus to: Based on the array, determine a trailing edge of the measurement relaxation region with respect to a direction of movement that extends across the first cell coverage perpendicular to the direction of movement of the serving cell; and wherein the measurement relaxation region includes a portion of the first cell coverage delimited by the trailing edge.

7. The apparatus according to claim 1 or 2, wherein the one or more offset parameters include an array of distances associated with a plurality of reference positions within the serving cell; and the at least one memory includes instructions that, when executed by the at least one processor, cause the apparatus to:[[]] Based on the array, determine a trailing edge of the measurement relaxation region with respect to a direction of movement that extends across the first cell coverage perpendicular to the direction of movement of the serving cell; and wherein the measurement relaxation region includes a portion of the first cell coverage delimited by the trailing edge.

8. The apparatus according to any one of the preceding claims, wherein the at least one memory further includes instructions that, when executed by the at least one processor, cause the apparatus to:[[]] Determine a measurement region based on the first cell coverage that is not included in the measurement relaxation region; Determine when the client node is within the measurement region; And Perform the mobility measurement when the client node is within the measurement region.

9. The apparatus according to any one of the preceding claims, wherein the at least one memory further includes instructions that, when executed by the at least one processor, cause the apparatus to:[[]] Compare a distance between the trailing edge of the measurement relaxation region with respect to the direction of movement of the serving cell and the client node with a predefined threshold; and Perform the mobility measurement when the distance between the trailing edge and the client node is less than the predefined threshold.

10. The apparatus according to any one of claims 1 to 8, wherein the indication of the direction of movement of the serving cell includes satellite ephemeris; and wherein the at least one memory further includes instructions that, when executed by the at least one processor, cause the apparatus to:[[]] Estimate a time when the client node is before the trailing edge of the measurement relaxation region with respect to the direction of movement based on the current position of the client node and the satellite ephemeris; Set a timer based on the estimated time; And Initiate the mobility measurement based on expiration of the timer.

11. The apparatus according to any one of claims 1 to 8, wherein the indication of the direction of movement of the serving cell includes satellite ephemeris; and wherein the at least one memory further includes instructions that, when executed by the at least one processor, cause the apparatus to:[[]] Estimate a time point when the client node is at the trailing edge of the measurement relaxation region with respect to the direction of movement based on the current position of the client node and the satellite ephemeris; and Perform the mobility measurement at the estimated time point.

12. An apparatus, comprising: At least one processor; And At least one memory including instructions which, when executed by the at least one processor, cause the apparatus to at least: Send to a client node parameters related to a base station providing a serving cell to the client node in a non-terrestrial network, the parameters including at least one or more offset parameters of at least one of a reference position of the serving cell and a time for a distance.

13. The apparatus according to claim 12, wherein the one or more offset parameters include at least one of the following: an array of time or distance parameters representing different distances from the first reference position, an array of time or distance parameters representing distances from the first reference position and positioned between 0 degrees and 180 degrees relative to an axis perpendicular to the direction of movement, an array of distances associated with a plurality of reference positions within the serving cell, or an array of distances associated with a plurality of reference positions within the serving cell on the axis perpendicular to the direction of movement.

14. A method comprising: Receiving from a base station providing a serving cell to a client node in a non-terrestrial network parameters including at least one of the following: a reference position of the serving cell, an indication of a direction of movement of the serving cell, and a cell radius parameter of the serving cell; Obtaining one or more offset parameters for at least one of a time or a distance relative to the reference position; Determining cell coverage based on the reference position and the cell radius parameter; Determining a measurement relaxation region within the cell coverage based on the one or more offset parameters and at least one of the parameters received from the base station; Obtaining a current position of the client node; Determining when the client node is within the measurement relaxation region; And When the client node is within the measurement relaxation region, determining that at least some of the mobility measurements in the mobility measurement are not performed by the client node.

15. The method according to claim 14, wherein the one or more offset parameters are received from the base station or determined by the client node.

16. The method according to claim 14 or 15, wherein the method comprises: Determining a second reference position of the serving cell based on the one or more offset parameters and the indication of the direction of movement; Determining a second cell coverage based on the second reference position and the cell radius parameter; And Determining that the measurement relaxation region includes at least a partially overlapping region of the second cell coverage and the first cell coverage.

17. The method according to claim 14 or 15, wherein the method comprises: Obtaining a second cell radius parameter for the serving cell; Determining a second reference position of the serving cell based on the one or more offset parameters and the indication of the direction of movement; Determining a second cell coverage based on the second reference position and the second cell radius parameter; And Determining the measurement relaxation region based on an overlapping region of the second cell coverage and the first cell coverage.

18. The method according to claim 16 or 17, wherein the indication of the direction of movement includes satellite ephemeris; and wherein the method further comprises: Determining the second reference position based on the satellite ephemeris and the one or more offset parameters.

19. The method according to claim 14 or 15, wherein the one or more offset parameters comprise an array of time or distance parameters representing different distances from the first reference position; and wherein the method further comprises: Based on the array, determining a trailing edge of the measurement relaxation region relative to the direction of movement across the first cell coverage perpendicular to the direction of movement of the serving cell; And wherein the measurement relaxation region comprises the portion of the first cell coverage defined by the trailing edge.

20. The method according to claim 14 or 15, wherein the one or more offset parameters comprise an array of distances associated with a plurality of reference positions within the serving cell; and wherein the method further comprises: Based on the array, determining a trailing edge of the measurement relaxation region relative to the direction of movement across the first cell coverage perpendicular to the direction of movement of the serving cell; And wherein the measurement relaxation region comprises the portion of the first cell coverage defined by the trailing edge.

21. The method according to any one of the preceding claims 14 to 20, wherein the method comprises: Based on the first cell coverage not included in the measurement relaxation region, determining a measurement region; Determining when the client node is within the measurement region; And When the client node is within the measurement region, performing the mobility measurement.

22. The method according to any one of the preceding claims 14 to 20, wherein the method further comprises: Comparing the distance between the trailing edge of the measurement relaxation region relative to the direction of movement of the serving cell and the client node with a predefined threshold; And When the distance between the trailing edge and the client node is less than the predefined threshold, performing the mobility measurement.

23. The method according to any one of the preceding claims 14 to 21, wherein the indication of the direction of movement of the serving cell comprises satellite ephemeris; and wherein the method comprises: Based on the current position of the client node and the satellite ephemeris, estimating the time when the client node is before the trailing edge of the measurement relaxation region relative to the direction of movement; Based on the estimated time, setting a timer; And Based on the expiration of the timer, starting the mobility measurement.

24. The method according to any one of the preceding claims 14 to 21, wherein the indication of the direction of movement of the serving cell comprises satellite ephemeris; and wherein the method comprises: Based on the current position of the client node and the satellite ephemeris, estimating the time point when the client node is at the trailing edge of the measurement relaxation region relative to the direction of movement; And Performing the mobility measurement at the estimated time point.

25. A method, comprising: Sending to a client node parameters related to a base station providing a serving cell to the client node in a non-terrestrial network, the parameters comprising at least one or more offset parameters of at least one of the reference position of the serving cell and the time for distance.

26. The method according to claim 25, wherein the one or more offset parameters include at least one of the following: an array of time or distance parameters representing different distances from the first reference position, an array of time or distance parameters representing different distances from the first reference position and positioned between 0 degrees and 180 degrees relative to an axis perpendicular to the direction of movement, an array of distances associated with a plurality of reference positions within the serving cell, or an array of distances associated with a plurality of reference positions within the serving cell on the axis perpendicular to the direction of movement.

27. A computer program product comprising computer program instructions configured to, when executed by a processor, cause a device to perform at least the following operations: receive parameters from a base station providing a serving cell to a client node in a non-terrestrial network, the parameters including at least one of the following: a reference position of the serving cell, an indication of a direction of movement of the serving cell, and a cell radius parameter of the serving cell; obtain one or more offset parameters for at least one of time or distance relative to the reference position; determine cell coverage based on the reference position and the cell radius parameter; determine a measurement relaxation region within the cell coverage based on the one or more offset parameters and at least one parameter received from the base station; obtain a current position of the client node; determine when the client node is located within the measurement relaxation region; and when the client node is located within the measurement relaxation region, determine that at least some of the mobility measurements in the mobility measurements are not performed by the client node.

28. A computer program product comprising computer program instructions configured to, when executed by a processor, cause a device to perform at least the following operations: send to a client node parameters related to a base station providing a serving cell to the client node in a non-terrestrial network, the parameters including at least the reference position of the serving cell and one or more offset parameters for at least one of time or distance.

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