GNSS independent non-terrestrial network

Abstract

According to some embodiments, a method is performed by a wireless device capable of communicating with a non-terrestrial network (NTN). The method comprises: obtaining a frequency common reference point (FCRP) and a timing common reference point (TCRP) for an NTN cell; determining an uplink pre-compensation for timing based on the TCRP; determining an uplink pre-compensation for Doppler offset based on the FCRP; and transmitting an uplink transmission using the determined timing pre-compensation and Doppler pre-compensation.

Description

GNSS INDEPENDENT NON-TERRESTRIAL NETWORKTECHNICAL FIELD

[0001] Embodiments of the present disclosure are directed to wireless communications and, more particularly to a global navigation satellite system (GNSS) independent non-terrestrial network (NTN).BACKGROUND

[0002] Third Generation Partnership Project (3GPP) Release 17 supports New Radio (NR), Long Term Evolution machine type communication (LTE-MTC) and narrowband Intemet-of- things (NB-IoT) based non-terrestrial networks (NTNs). NTN includes both satellite communication and communications using high-altitude platforms (HAPS). Particular embodiments and examples described herein focus on satellite communication, but the provided description may also be applied to a HAPS network.

[0003] A satellite radio access network usually includes the following components: a satellite that refers to a space-home platform; an earth-based gateway that connects the satellite to a base station or a core network, depending on the choice of architecture; a feeder link that refers to the link between a gateway and a satellite; and a service link that refers to the link between a satellite and a user equipment (UE).

[0004] Depending on the orbit altitude, a satellite may be categorized as low earth orbit (LEO), medium earth orbit (MEO), or geostationary earth orbit (GEO) satellite. LEO includes typical heights ranging from 500 - 1,500 km, with orbital periods ranging from 90 - 120 minutes. MEO includes typical heights ranging from 5,000 - 25,000 km, with orbital periods ranging from 3 - 15 hours. GEO includes height at about 35,786 km, with an orbital period matching the rotation of earth, i.e., of 24 hours.

[0005] A communication satellite typically generates several beams over a given area. The footprint of a beam on earth is usually in an elliptic shape. Each beam is typically providing coverage to cell in a fifth generation (5G) or fourth generation (4G) network. The footprint of a beam is also often referred to as a spotbeam. The footprint of a beam may move over the earth surface with the satellite movement or may be earth fixed using a satellite’s beam pointing mechanism to compensate for the satellite’s motion. The size of a spotbeam depends on the system design, which may range from tens of kilometers to a few thousands of kilometers.

[0006] FIGURE 1 illustrates an example architecture of a satellite network according to the transparent architecture where the base station is part of the gateway. This type of architecturemay be referred to as a satellite network with bent pipe transponders. Another popular architecture is the regenerative architecture where the base station is located on board the satellite. The depicted elevation angle of the service link is important because it impacts the distance between the satellite and the device, and the velocity of the satellite relative to the device.

[0007] As illustrated in FIGURE 1, a satellite may support a set of beams for providing coverage to a set of cells on earth. To provide continuous coverage, adjacent beams are often configured to overlap, which creates significant inter-cell interference.

[0008] Propagation delay is a main physical phenomenon in a satellite communication system that makes the design different from that of a terrestrial mobile system. For a bent pipe satellite network, the following delays are relevant.• One-way delay : from the base station to the UE via the satellite, or the other way around• Round-trip delay : from the base station to the UE via the satellite and from the UE back to the base station via the satellite• Differential delay: the delay difference of two selected points in the same spotbeam.

[0009] The propagation delay depends on the length of the signal path, which further depends on the elevation angles of the satellite seen by the base station and UE on the ground. According to 3GPP TR 38.811, round-trip delays in the range 10-30 ms for LEO and around 500 ms for a GEO satellite system are expected. In contrast, the round-trip time is normally no more than 1 ms for typical terrestrial cellular networks.

[0010] Generally, within a spot beam covering one cell, the delay may be divided into a common delay component and a differential delay component. The common delay is the same for all UEs in the cell and is determined with respect to a reference point in the spot beam. In contrast, the differential delay is different for different UEs and depends on the difference between the common delay and the propagation delay between the UE and the base station.

[0011] The differential delay is mainly due to the different path lengths of the service links, because the feeder link is normally the same for terminals in the same spotbeam. Further, the differential delay is mainly determined by the size of the spotbeam. The differential delay may range from sub-millisecond (for spotbeam on the order of tens of kilometres) to tens of milliseconds (for spotbeam on the order of thousands of kilometres).

[0012] Doppler is another major physical phenomenon to be accounted for in a satellite communication system. The following Doppler effects are particularly relevant.• Doppler shift: the shift of the signal frequency due to the motion of the transmitter, the receiver, or both.• Doppler variation rate: the derivative of the Doppler shift function of time, i.e., it characterizes how fast the Doppler shift evolves over time.

[0013] Doppler effects depend on the relative speed of the satellites and the UE and the carrier frequency.

[0014] GEO satellites are fixed in principle relative to the surface of the Earth and thus do not induce Doppler shift. In reality, however, GEO satellites move around their nominal orbital positions due to, for example, perturbations. A GEO satellite is typically manoeuvred to be within a box in space, which limits the Doppler shifts to become negligible. A GSO satellite may have an inclination angle relative to the Earth equator and will therefore move mainly in north-south direction relative to a fixed point on the Earth’s surface. This will create a small but non-negligible Doppler shift.

[0015] The Doppler effects become remarkable for MEO and LEO satellites. Table 4 gives example Doppler shifts and rates of NGSO satellites. The Doppler shifts and rates due to the NGSO satellite movement should be properly considered in the communications system design.Table 4: Doppler shifts and variation rates of NGSO satellites (extracted from Table 5.3.43.2-7 in 3GPP TR 38.811)

[0016] The solution selected by 3GPP to combat the large and variable time delays and frequency offsets is based on that the satellite access node (SAN), i.e., the NTN gNB, indicates the satellite’s orbit and the satellite’s position in the orbit to the devices on earth using system information (SI) signaling. Each NTN device is global navigation satellite system (GNSS)capable and determines its own position using this capability. After synchronizing to the downlink frame structure in time and frequency, the device acquires the NTN SI and derives the current satellite position. Based on this and its own position, the device calculates an initial estimate of the timing advance (TA) used to offset its uplink frame structure relative to its downlink frame structure to compensate for the propagation delay of the service link.

[0017] This initial TA offset secures that the uplink transmissions from all devices in a cell are received in a synchronous fashion at the SAN despite the long NTN delays. The initial TA is later on, during the connection setup and the connection, corrected based on TA adjustments received from the network, as well as TA adjustments made autonomously by the UE based on updated satellite position and UE position estimates. Optionally, the network may also broadcast in SI a Common TA, corresponding to the propagation delay of the feeder link or a part thereof, that the UE applies in addition.

[0018] The device also uses its own position, the satellite’s position and movement, and knowledge of the downlink frequency to which the device synchronized, to compute the anticipated downlink and uplink Doppler frequency offsets on the service link. Based on this calculation, the UE can adjust its uplink carrier frequency to compensate for the Doppler offsets, so that the uplink transmission is received by the SAN at the intended carrier frequency. Doppler frequency offsets of the feeder link are assumed to be compensated by the network in a way that is not specified by 3GPP.

[0019] The UE dependency on GNSS introduces an unwanted dependency in the 3GPP protocol. GNSS is, e.g., vulnerable to jamming, and does not work well indoors. Due to these reasons, solutions to reduce or even remove this dependency are being discussed in the NTN research and standards community.

[0020] One attractive solution is to let the SAN broadcast an estimate of the UE position to the UE. The UE can then use this position instead of its true position to perform its TA and Doppler offset estimates. This procedure introduces time and frequency errors on the uplink. With the estimated position sufficiently close to the actual UE position, these time-frequency errors will be within limits that can be managed by the SAN receiver.

[0021] Yet another solution is that the network determines a reference point in a cell, e.g., the cell center and shifts its downlink frame structure relative to its uplink frame structure according to the round-trip time observed between the satellite and the reference point. A UE located at the reference point will thus experience a timing advance equal to 0. The SAN canoffset its used downlink carrier frequency by an amount that compensates for the anticipated downlink Doppler offset so that a UE located at the reference point does not experience any downlink Doppler shift of the carrier frequency. As long as all UEs are sufficiently close to the reference point, this method can be explored to offer satellite connectivity in a backwards compatible manner to regular unmodified devices not offering explicit support for NTN. This approach is believed to be used by recent commercial initiatives to connect existing 4G LTE devices to NTN (see https: / / www.datacenterdynamics.com / at en / news / ast-spacemobile-dials- in-satellite-call-with-att-and-rakuten / ).

[0022] There currently exist certain challenges. For example, a practical solution to remove the UE GNSS dependency in NTN is to determine a single common reference point (CRP) per cell. If broadcast from the SAN, all UEs in the cell may use the CRP as an estimate of their position to pre-compensate for uplink time and frequency offsets, e.g., when performing the initial physical random access channel (PRACH) preamble transmission to initiate a connection. Alternatively, the SAN may use the reference point to perform the time-frequency downlink pre-compensation to manage the time-frequency offsets observed in NTNs to enable connectivity to 4G and / or 5G devices.

[0023] The 4G and 5G NR random-access response (RAR) message sent from the network to the UE, in response to the UE’s PRACH preamble transmission, only supports a positive correction (i.e., an increase) of the UE’s initial TA value. This restriction requires the CRP to be placed at a location with a distance to the satellite that is less than the distance between the UEs in the cell and the satellite, as illustrated in FIGURE 2.

[0024] FIGURE 2 illustrates an example wherein a single CRP placed at a location with a distance to a satellite that is less than a distance between the UEs in the cell and the satellite. This restriction in choice of CRP, however, leads to large time and frequency errors on the UEs first transmission.SUMMARY

[0025] As described above, certain challenges currently exist with a global navigation satellite system (GNSS) independent non-terrestrial network (NTN). Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. For example, particular embodiments reduce the downlink / uplink time-frequency error observed by the satellite access network (SAN) as well as for NTN user equipment (UEs).

[0026] In general, particular embodiments go beyond a single common reference point (CRP). Multiple CRPs may be used to limit the time-frequency error observed in an NTN. A CRP may be used for both time-frequency correction, but there may also be different CRPs used by the SAN or NTN UEs for their time and frequency compensation determination.

[0027] According to some embodiments, a method is performed by a wireless device capable of communicating with an NTN. The method comprises: obtaining a frequency common reference point (FCRP) and a timing common reference point (TCRP) for an NTN cell; determining an uplink pre-compensation for timing based on the TCRP; determining an uplink pre-compensation for Doppler offset based on the FCRP; and transmitting an uplink transmission using the determined timing pre-compensation and Doppler pre-compensation.

[0028] In particular embodiments, the FCRP is located at a center of the NTN cell. The FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell The TCRP may be located at a cell edge closest to a satellite providing the NTN cell. The TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a wireless device in the cell and the satellite providing the NTN cell. The TCRP may be located at a nadir point in the NTN cell.

[0029] In particular embodiments, at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves. The TCRP may move to maintain a position in a middle of a cone formed by a beam from a satellite providing the NTN cell.

[0030] In particular embodiments, at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface. In particular embodiments, the TCRP is located at a maximum wireless device altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell, and the FCRP is located at half the maximum wireless device altitude on an axis of the cone defined by the beam.

[0031] In particular embodiments, the method further comprises determining a distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell before accessing the NTN cell.

[0032] In particular embodiments, the method further comprises determining a distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before accessing the NTN cell.

[0033] In particular embodiments, the threshold value is based on a cyclic prefix value used by the wireless device in the NTN cell.

[0034] In particular embodiments, the FCRP and the TCRP are located at the same position.

[0035] In particular embodiments, the TCRP and FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel (PRACH) occasion and the method further comprises obtaining a second TCRP and second FCRP associated with a second PRACH occasion.

[0036] In particular embodiments, obtaining the FCRP and the TCRP further comprises obtaining trajectory information for at least one of the FCRP and the TCRP.

[0037] According to some embodiments, a wireless device comprises processing circuitry operable to perform any of the methods of the wireless receiver described above.

[0038] Also disclosed is a computer program product comprising a non-transitory computer readable medium storing computer readable program code, the computer readable program code operable, when executed by processing circuitry to perform any of the methods performed by the wireless device described above.

[0039] According to some embodiments, a method is performed by a network node comprised in an NTN. The method comprises: obtaining a FCRP and a TCRP for a wireless device in an NTN cell; determining a downlink pre-compensation for timing based on the TCRP; determining a downlink pre-compensation for Doppler offset based on the FCRP; and transmitting a downlink transmission to the wireless device using the determined timing precompensation and Doppler pre-compensation.

[0040] In particular embodiments, the method further comprises determining a distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell and barring the wireless device from accessing the NTN cell.

[0041] In particular embodiments, the method further comprises determining a distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before allowing the wireless device to access the NTN cell.

[0042] According to some embodiments, a network node comprises processing circuitry operable to perform any of the methods of the network node described above.

[0043] Also disclosed is a computer program product comprising a non-transitory computer readable medium storing computer readable program code, the computer readable program code operable, when executed by processing circuitry to perform any of the methods performed by the network node described above.

[0044] Certain embodiments may provide one or more of the following technical advantages. For example, particular embodiments limit the time-frequency error observed by the SAN and NTN UEs. Particular embodiments may improve the latency and power consumption when accessing a NTN network.BRIEF DESCRIPTION OF THE DRAWINGS

[0045] For a more complete understanding of the disclosed embodiments and their features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:FIGURE 1 illustrates an example architecture of a satellite network according to the transparent architecture where the base station is part of the gateway;FIGURE 2 illustrates an example wherein a single common reference point (CRP) placed at a location with a distance to a satellite that is less than a distance between the user equipment (UEs) in the cell and the satellite;FIGURE 3 illustrates the use of a frequency CRP (FCRP)and a time CRP (TCRP);FIGURE 4 illustrates the use of a FCRP and TCRP using three coordinates;FIGURE 5 illustrates the use of a flexible / movable TCRP;FIGURE 6 illustrates the use of a flexible / movable TCRP when the nadir point passes the cell;FIGURE 7 illustrates the concept of a moving TCRP, where the TCRP is located a suitable distance from the Earth on the middle line of the cone formed by the beam (or cluster of beams) covering the cell area;FIGURE 8 illustrates an example communication system, according to certain embodiments;FIGURE 9 illustrates an example user equipment (UE), according to certain embodiments;FIGURE 10 illustrates an example network node, according to certain embodiments;FIGURE 11 illustrates a block diagram of a host, according to certain embodiments;FIGURE 12 illustrates a method performed by a wireless device, according to certain embodiments; andFIGURE 13 illustrates a method performed by a network node, according to certain embodiments.DETAILED DESCRIPTION

[0046] As described above, certain challenges currently exist with a global navigation satellite system (GNSS) independent non-terrestrial network (NTN). Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges, particular embodiments reduce the downlink / uplink time-frequency error observed by the satellite access network (SAN) as well as for NTN user equipment (UEs).

[0047] In general, particular embodiments go beyond a single common reference point (CRP). Multiple CRPs may be used to limit the time-frequency error observed in an NTN. A CRP may be used for both time-frequency correction, but there may also be different CRPs used by the SAN or NTN UEs for their time and frequency compensation determination.

[0048] Particular embodiments are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0049] A first set of embodiments includes separate CRPs for time and frequency. In some embodiments, two separate CRPs are defined, a first that UEs or a SAN in an NTN use for calculation and pre-compensation of its timing, and a second that the SAN or the NTN UEs use for calculation and pre-compensation for its Doppler frequency offset.

[0050] The frequency CRP (FCRP) may be located at the center of the NTN cell to limit the maximum error in the Doppler pre-compensation performed by the UEs or the SAN. The time CRP (TCRP) may be located at the cell edge closest to the satellite to secure that the TCRP- satellite distance is less than the distance between the UEs in the cell and the satellite. If the nadir point is inside the cell, the TCRP may be placed at the nadir point of the cell.

[0051] FIGURE 3 illustrates the use of a FCRP and TCRP. In the embodiment above, a CRP is defined by two horizontal coordinates (e.g., latitude and longitude) and is assumed to belocated at the surface of the Earth, which may be defined by the WGS 84 ellipsoid (also known as the WGS 84 reference ellipsoid), or by a fixed pre-configured altitude.

[0052] In another embodiment, a CRP is defined by three coordinates (e.g., latitude, longitude and altitude) and may be located, e.g., above the surface of the Earth. In this case, the TCRP may be placed at an assumed maximum UE altitude and on the surface of the cone defined by the beam to ensure that the distance between the TCRP and the satellite is less than the distance between the satellite and UEs. The FCRP may be placed at half the assumed maximum UE altitude on the axis of the cone defined by the beam to limit the maximum error in the Doppler pre-compensation performed by the UEs (see an illustration in FIGURE 5). If the nadir point is inside the cell, the TCRP may be placed at the assumed max UE altitude on the line between the nadir point and the satellite.

[0053] FIGURE 4 illustrates the use of a FCRP and TCRP using three coordinates.

[0054] In other embodiments, the FCRP is placed at the point that minimizes the maximum error in the Doppler pre-compensation across the cell, which may be different from the center point.

[0055] In some embodiments, upon detecting that a UE is closer to the satellite than the TCRP is (e.g., via comparing the arrival time of the random access Message 1 or Message A from the UE at the gNB with a timing reference at the gNB), the network performs at least one of the following actions: (a) preventing or barring the UE from accessing the network; and / or (b) updating the TCRP based on the above embodiments.

[0056] In some embodiments, if a UE detects that its distance to the satellite is smaller than the distance from the broadcast TCRP to the satellite (e.g., when the UE has an estimate of its location based on GNSS or other means of positioning), the UE abstains from accessing the satellite access network.

[0057] As the satellite moves, the CRPs may be adjusted. In one example, when the nadir point of the satellite does not pass through the cell, the TCRP is moved to make sure it is continuously located at the cell edge closest to the satellite.

[0058] FIGURE 5 illustrates the use of a flexible / movable TCRP.

[0059] In one example, when the nadir point of the satellite passes through the cell, the TCRP is at the nadir point when the nadir point is in the cell, and otherwise, the TCRP is at the cell edge closest to the satellite.

[0060] FIGURE 6 illustrates the use of a flexible / movable TCRP when the nadir point passes the cell.

[0061] In some embodiments, a moving reference point may be used for the timing (i.e., a moving TCRP) to improve the TCRP’s probability to always be closer to the satellite than any UE in the cell (while the FCRP may be fixed and would typically be located at the center of the cell). In these embodiments, it is recognized that some distance from the ground in the middle of the cone formed by the beam (or cluster of beams) that cover the cell area is generally the best (or at least a very good) place for a TCRP, if the aim is to place the TCRP closer to the satellite than any UE in the cell, while still not making the differences between the TCRP and the actual positions of the UEs in the cell too large. Because the satellite is moving, the cone formed by the beam (or cluster of beams) consequently also moves, the TCRP also has to move to maintain its position in the middle of the cone. This is illustrated in FIGURE 7.

[0062] FIGURE 7 illustrates the concept of a moving TCRP, where the TCRP is located a suitable distance from the Earth on the middle line of the cone formed by the beam (or cluster of beams) covering the cell area.

[0063] The UEs in the cell should be informed of the trajectory of the moving TCRP, so that the UEs at any point in time know where the TCRP is located. This configuration may be achieved by broadcasting the same kind of ephemeris information as for the satellite (with an associated epoch time and an associated validity time), albeit adapted to the TCRP’s trajectory. As another alternative, the configuration information may have the form of an epoch time, a position, a velocity vector, a first-order time derivative of the velocity vector, a second-order time derivative of the velocity vector, etc. (an arbitrary number of derivatives), and an associated validity time. Alternatively, the configuration information may include one or more (e.g., K) positions and a validity time for each position, and an epoch time or time reference relative to which the validity duration is indicated. For example, the network broadcasts K=3 (position, validity time) pairs {(P1,T1), (P2,T2), (P3,T3)} in a system information block (SIB) and the UE is expected to use position Pl for a duration T1 relative to the epoch / reference time, then a position P2 after the expiry of Pl for a duration T2, then a position P3 after the expiry of P2 for a duration T3. Note that the first time duration T1 may be relative to the epoch / reference time (e.g., the subframe carrying the SIB) while the subsequent time duration T2 may be relative to Tl, and T3 may be relative to T2.

[0064] Yet another alternative is that the configuration information indicates a fraction, e.g., F, of the length of the cone’s middle line from the surface of the WGS 84 ellipsoid and the satellite. With this alternative, the TCRP is always located at a point on the cone’s middle line at a distance from the middle line’s intersection with the WGS 84 ellipsoid representing a fraction F of the full length of the cone’s middle line from the WGS 84 ellipsoid to the satellite.

[0065] Yet another alternative is that the configuration information indicates a fixed distance D from the satellite, and the TCRP is located on the middle line of the cone at distance D from the satellite (and this is valid as long as the satellite serves the cell). Yet another alternative is that the configuration information indicates a fixed distance D from the WGS 84 ellipsoid, and the TCRP is located on the middle line of the cone at distance D from the WGS ellipsoid wherein the distance is measured along the cone’s middle line (and this is valid as long as the satellite serves the cell). Yet another alternative is that the configuration information indicates a fixed altitude A (measured from the WGS 84 ellipsoid), and the TCRP is located on the middle line of the cone at altitude A (measured along a straight line that is orthogonal to the WGS 84 ellipsoid, i.e. the line is a normal to the WGS 84 ellipsoid) (and this is valid as long as the satellite serves the cell).

[0066] As an alternative to placing the moving TCRP at a point on the middle line of the cone formed by the beam (or cluster of beams) covering the cell area is to place the moving TCRP a suitable distance from the ground at a point on the line between the center of the cell (or the FCRP assuming that the FCRP is located at the center of the cell) and the satellite. All the above-described alternatives for how the UEs may be configured with the information about the trajectory of the moving TCRP may be used for this alternative TCRP placement too, with a difference being that the cone’s middle line is replaced by the line between the center of the cell and the satellite.

[0067] In all the above alternatives, the configuration information (describing the trajectory of the moving TCRP) may be broadcast to all UEs in the cell, e.g., in system information, e.g., in SIB19 or in a 6G SIB corresponding to SIB19 in 5G. In addition, or as an alternative, the configuration information may be sent from the network (e.g., a gNB) to a UE using dedicated signaling, e.g., dedicated Radio Resourced Control (RRC) signaling, e.g., in an RRC message constituting a Handover Command or an RRCReconflguration message.

[0068] If a UE is still closer to the satellite than the TCRP, the UE will in some embodiments not be allowed to transmit and will not be served by the network. In other embodiments, if aUE is closer to the satellite than the TCRP is, the UE may still be served depending on the circumstances. Some different variants or cases are listed below.

[0069] In some embodiments, a UE that is closer to the satellite than the TCRP is allowed to transmit if the absolute value of the difference between the TCRP-satellite round trip time (RTT) and the UE-satellite RTT is smaller than a certain threshold value, e.g., smaller than the cyclic prefix (CP), or, as another option, smaller than a certain fraction (e.g., hall) of the CP.

[0070] In some embodiments, the CP in the condition is the CP of the random access preamble and the UE is allowed to transmit a random access preamble (and possibly random access Msg3) and after that the network can adjust the UE’s TA to its correct negative value using relative timing advance adjustments, e.g. using Timing Advance Command medium access control (MAC) control elements (CEs) (or corresponding signaling).

[0071] In some embodiments, the CP in the condition is the CP for regular non-random access transmissions, e.g., physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH) transmissions.

[0072] In some embodiments, a UE that is closer to the satellite than the TCRP is allowed to transmit if the absolute value of the difference between the TCRP-satellite RTT and the UE- satellite RTT is smaller than a certain threshold value, which may be configured (e.g., broadcast in the system information) or specified in a standard (and which may be unrelated to the CP).

[0073] In some embodiments, the threshold value may be different for random access preamble transmissions than for non-random access related transmissions, e.g., PUSCH and PUCCH transmissions.

[0074] In some embodiments, the FCRP and the TCRP are collocated, i.e., they are one and the same point, and they move in the way the TCRP moves in the embodiments described above.

[0075] A second set of embodiments includes multiple CRPs. In one embodiment, multiple TCRPs and / or FCRPs are defined that are spread out over the surface of a cell and possibly at different altitudes. Each pair of {TCRP, FCRP} is associated with a different PRACH timefrequency occasion. A UE may attempt multiple consecutive PRACH transmissions in different PRACH occasions (PRO), each coupled with a distinct pair of {TCRP, FCRP} signaled by the network. For each PRO-TCRP combination, the UE will perform uplink timefrequency compensation based on the assumed {TCRP, FCRP} pair before making the PRACH transmission.

[0076] As a special case of the above embodiment, only a single FCRP is defined, together with multiple TCRPs. Similarly, there may be multiple FCRPs with a single TCRP.

[0077] FIGURE 8 illustrates an example of a communication system 100 in accordance with some embodiments. In the example, the communication system 100 includes a telecommunication network 102 that includes an access network 104, such as a radio access network (RAN), and a core network 106, which includes one or more core network nodes 108. The access network 104 includes one or more access network nodes, such as network nodes 110a and 110b (one or more of which may be generally referred to as network nodes 110), or any other similar 3GPP access node or non-3GPP access point. The network nodes 110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 112a, 112b, 112c, and 112d (one or more of which may be generally referred to as UEs 112) to the core network 106 over one or more wireless connections.

[0078] Moreover, as will be appreciated by those of skill in the art, a network node is not necessarily limited to an implementation in which a radio portion and a baseband portion are supplied and integrated by a single vendor. Thus, it will be understood that network nodes include disaggregated implementations or portions thereof. For example, in some embodiments, the telecommunication network 102 includes one or more Open-RAN (ORAN) network nodes. An ORAN network node is a node in the telecommunication network 102 that supports an ORAN specification (e.g., a specification published by the O-RAN Alliance, or any similar organization) and may operate alone or together with other nodes to implement one or more functionalities of any node in the telecommunication network 102, including one or more network nodes 110 and / or core network nodes 108.

[0079] Examples of an ORAN network node include an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O- CU-CP) or an O-CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp) or anon-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification). The network node may support a specification by, for example, supporting an interface defined by the ORAN specification, such as an Al, Fl, Wl, El, E2, X2, Xn interface, an open fronthaul user plane interface, or an open fronthaul management plane interface. Moreover, an ORAN access node may be a logical node in a physical node. Furthermore, an ORAN network node may beimplemented in a virtualization environment (described further below) in which one or more network functions are virtualized. For example, the virtualization environment may include an O-Cloud computing platform orchestrated by a Service Management and Orchestration Framework via an 0-2 interface defined by the O-RAN Alliance or comparable technologies.

[0080] In some embodiments, the telecommunication network 102 includes a non-terrestrial network, NTN. Unless otherwise described herein, embodiments applicable for NTN may be implanted according to the following clauses. An NTN is telecommunication network where the radio access payload is conveyed via satellite to a ground station. E-UTRAN supports radio access over non-terrestrial networks for BL UEs, UEs in enhanced coverage andNB-IoT UEs. Support for non-terrestrial networks encompasses platforms that provide radio access through Geosynchronous orbits (GSO), Non-Geosynchronous Orbit (NGSO), which includes Low- Earth Orbit (LEO) and Medium Earth Orbit (MEO) or High Altitude Platform Systems (HAPS). Another example of a Non-Terrestrial Network (NTN) provides non-terrestrial NR access to the UE by means of an NTN payload and an NTN Gateway, a service link between the NTN payload and a UE, and a feeder link between the NTN Gateway and the NTN payload exists. An access network 104 may include an NTN access network such as the 3GPP Satellite Access Node (SAN) which comprises Non-NTN infrastructure base station functions (e.g. eNB / gNB) a terrestrial Gateway which provides the interface to the feeder link to an NTN payload RF node. In some embodiments a network node 110 comprises a SAN, wherein the location of base station functions for a network node 110 (described above for the general terrestrial access) vary between residing in the terrestrial access network node part of the SAN and the NTN Payload RF node functions depending on the supported architecture. One example of NTN architecture is called bent pipe or transparent architecture where the radio frequency processing function (transceiver) on a satellite platform is interconnected with a terrestrial base station, also known as transparent architecture, and the NTN payload is passed transparently, no unpacking. Another example of NTN architecture is called regenerative architecture, where part or all of the eNB / gNB can be in the satellite.

[0081] In some examples a SAN includes an open radio unit (O-RU), an open distributed unit (O-DU), an open central unit (O-CU), including an O-CU control plane (O-CU-CP) or an O- CU user plane (O-CU-UP), a RAN intelligent controller (near-real time or non-real time) hosting software or software plug-ins, such as a near-real time control application (e.g., xApp)or a non-real time control application (e.g., rApp), or any combination thereof (the adjective “open” designating support of an ORAN specification).

[0082] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 100 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 100 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0083] The UEs 112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 110 and other communication devices. Similarly, the network nodes 110 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 112 and / or with other network nodes or equipment in the telecommunication network 102 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 102.

[0084] In the depicted example, the core network 106 connects the network nodes 110 to one or more hosts, such as host 116. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 106 includes one more core network nodes (e.g., core network node 108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 108. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0085] The host 116 may be under the ownership or control of a service provider other than an operator or provider of the access network 104 and / or the telecommunication network 102 and may be operated by the service provider or on behalf of the service provider. The host 116 may host a variety of applications to provide one or more services. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0086] As a whole, the communication system 100 of FIGURE 8 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0087] In some examples, the telecommunication network 102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 102. For example, the telecommunications network 102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC)ZMassive loT services to yet further UEs.

[0088] In some examples, the UEs 112 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 104. Additionally, a UE may be configured for operating in single- or multi -RAT or multi-standard mode. For example, aUE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

[0089] In the example, the hub 114 communicates with the access network 104 to facilitate indirect communication between one or more UEs (e.g., UE 112c and / or 112d) and network nodes (e.g., network node 110b). In some examples, the hub 114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 114 may be a broadband router enabling access to the core network 106 for the UEs. As another example, the hub 114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 110, or by executable code, script, process, or other instructions in the hub 114. As another example, the hub 114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 114 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 114 acts as a proxy server or orchestrator for the UEs, in particular if one or more of the UEs are low energy loT devices.

[0090] The hub 114 may have a constant / persistent or intermittent connection to the network node 110b. The hub 114 may also allow for a different communication scheme and / or schedule between the hub 114 and UEs (e.g., UE 112c and / or 112d), and between the hub 114 and the core network 106. In other examples, the hub 114 is connected to the core network 106 and / or one or more UEs via a wired connection. Moreover, the hub 114 may be configured to connect to an M2M service provider over the access network 104 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 110 while still connected via the hub 114 via a wired or wireless connection. In some embodiments, the hub 114 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 110b. In other embodiments, the hub 114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 110b, but which isadditionally capable of operating as a communication start and / or end point for certain data channels.

[0091] FIGURE 9 shows a UE 200 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3 GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0092] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle- to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0093] The UE 200 includes processing circuitry 202 that is operatively coupled via a bus 204 to an input / output interface 206, a power source 208, a memory 210, a communication interface 212, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in FIGURE 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0094] The processing circuitry 202 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 210. The processing circuitry 202 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 202 may include multiple central processing units (CPUs).

[0095] In the example, the input / output interface 206 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 200. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0096] In some embodiments, the power source 208 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 208 may further include power circuitry for delivering power from the power source 208 itself, and / or an external power source, to the various parts of the UE 200 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 208. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 208 to make the power suitable for the respective components of the UE 200 to which power is supplied.

[0097] The memory 210 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 210 includes one or more application programs 214, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 216. The memory 210 may store, for use by the UE 200, any of a variety of various operating systems or combinations of operating systems.

[0098] The memory 210 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 210 may allow the UE 200 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 210, which may be or comprise a device-readable storage medium.

[0099] The processing circuitry 202 may be configured to communicate with an access network or other network using the communication interface 212. The communication interface 212 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 222. The communication interface 212 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 218 and / or a receiver 220 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 218 and receiver 220 may becoupled to one or more antennas (e.g., antenna 222) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0100] In the illustrated embodiment, communication functions of the communication interface 212 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0101] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 212, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0102] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0103] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer,a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 200 shown in FIGURE 9.

[0104] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0105] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0106] FIGURE 10 shows anetwork node 300 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment,in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., O-RU, O-DU, O-CU), components of a satellite access network (SAN) (e.g., terrestrial base station, gateway, NTN payload RF function) (the NTN and components of the satellite network are described in more detail with respect to FIGURE 8).

[0107] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0108] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0109] The network node 300 includes a processing circuitry 302, a memory 304, a communication interface 306, and a power source 308. The network node 300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 300 may be configured to support multiple radio access technologies (RATs). In suchembodiments, some components may be duplicated (e.g., separate memory 304 for different RATs) and some components may be reused (e.g., a same antenna 310 may be shared by different RATs). The network node 300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 300.

[0110] The processing circuitry 302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 300 components, such as the memory 304, to provide network node 300 functionality.[oni] In some embodiments, the processing circuitry 302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 302 includes one or more of radio frequency (RF) transceiver circuitry 312 and baseband processing circuitry 314. In some embodiments, the radio frequency (RF) transceiver circuitry 312 and the baseband processing circuitry 314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 312 and baseband processing circuitry 314 may be on the same chip or set of chips, boards, or units.

[0112] The memory 304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 302. The memory 304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 302 and utilized by the network node 300. The memory 304 may be used to store anycalculations made by the processing circuitry 302 and / or any data received via the communication interface 306. In some embodiments, the processing circuitry 302 and memory 304 is integrated.

[0113] The communication interface 306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 306 comprises port(s) / terminal(s) 316 to send and receive data, for example to and from a network over a wired connection. The communication interface 306 also includes radio front-end circuitry 318 that may be coupled to, or in certain embodiments a part of, the antenna 310. Radio front-end circuitry 318 comprises filters 320 and amplifiers 322. The radio front-end circuitry 318 may be connected to an antenna 310 and processing circuitry 302. The radio front-end circuitry may be configured to condition signals communicated between antenna 310 and processing circuitry 302. The radio front-end circuitry 318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 320 and / or amplifiers 322. The radio signal may then be transmitted via the antenna 310. Similarly, when receiving data, the antenna 310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 318. The digital data may be passed to the processing circuitry 302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0114] In certain alternative embodiments, the network node 300 does not include separate radio front-end circuitry 318, instead, the processing circuitry 302 includes radio front-end circuitry and is connected to the antenna 310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 312 is part of the communication interface 306. In still other embodiments, the communication interface 306 includes one or more ports or terminals 316, the radio front-end circuitry 318, and the RF transceiver circuitry 312, as part of a radio unit (not shown), and the communication interface 306 communicates with the baseband processing circuitry 314, which is part of a digital unit (not shown).

[0115] The antenna 310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 310 may be coupled to the radio front-end circuitry 318 and may be any type of antenna capable of transmitting and receiving data and / orsignals wirelessly. In certain embodiments, the antenna 310 is separate from the network node 300 and connectable to the network node 300 through an interface or port.

[0116] The antenna 310, communication interface 306, and / or the processing circuitry 302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 310, the communication interface 306, and / or the processing circuitry 302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0117] The power source 308 provides power to the various components of network node 300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 308 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 300 with power for performing the functionality described herein. For example, the network node 300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 308. As a further example, the power source 308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0118] Embodiments of the network node 300 may include additional components beyond those shown in FIGURE 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 300 may include user interface equipment to allow input of information into the network node 300 and to allow output of information from the network node 300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 300.

[0119] FIGURE 11 is a block diagram of a host 400, which may be an embodiment of the host 116 of FIGURE 8, in accordance with various aspects described herein. As used herein, the host 400 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtualmachine, container, or processing resources in a server farm. The host 400 may provide one or more services to one or more UEs.

[0120] The host 400 includes processing circuitry 402 that is operatively coupled via a bus 404 to an input / output interface 406, a network interface 408, a power source 410, and a memory 412. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 3 and 4, such that the descriptions thereof are generally applicable to the corresponding components of host 400.

[0121] The memory 412 may include one or more computer programs including one or more host application programs 414 and data 416, which may include user data, e.g., data generated by a UE for the host 400 or data generated by the host 400 for a UE. Embodiments of the host 400 may utilize only a subset or all of the components shown. The host application programs 414 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 414 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 400 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 414 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0122] FIGURE 12 is a flowchart illustrating an example method 1200 in a wireless device, according to certain embodiments. In particular embodiments, one or more steps of FIGURE 12 may be performed by UE 200 described with respect to FIGURE 9. The wireless device is capable of communicating with an NTN.

[0123] The method may begin at step 1212, where the wireless device (e.g., UE 200) obtains a FCRP and a TCRP for an NTN cell. The wireless device may obtain the FCRP and the TCRP from a network node via broadcast signaling (e.g., SIB) or via dedicated signaling (e.g., RRC). Obtaining a FCRP / TCRP refers to obtaining an indication of a location of the FCRP / TCRP,such as two-dimensional coordinates or three-dimensional coordinates. When the FCRP or TCRP moves, obtaining the FCRP / TCRP may include obtaining trajectory information describing the movement of the FCRP / TCRP. Examples of trajectory information are described in more detail above.

[0124] In particular embodiments, the FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell. For example, the FCRP may be located at a center of the NTN cell.

[0125] The TCRP may be located at a cell edge closest to a satellite providing the NTN cell. The TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a wireless device in the cell and the satellite providing the NTN cell. The TCRP may be located at a nadir point in the NTN cell.

[0126] In particular embodiments, at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves. The TCRP may move to maintain a position in a middle of a cone formed by a beam from a satellite providing the NTN cell.

[0127] In particular embodiments, at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface. In particular embodiments, the TCRP is located at a maximum wireless device altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell, and the FCRP is located at half the maximum wireless device altitude on an axis of the cone defined by the beam. An example is illustrated in FIGURE 5.

[0128] In particular embodiments, the FCRP and the TCRP are located at the same position. In such a scenario, obtaining the FCRP and TCRP may comprise obtaining a single CRP that the wireless device may use as both the FCRP and TCRP.

[0129] In particular embodiments, the TCRP and FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel (PRACH) occasion and the method further comprises obtaining a second TCRP and second FCRP associated with a second PRACH occasion. In such a scenario, obtaining the TCRP and FCRP may comprise obtaining a plurality of TCRP and / or FCRP.

[0130] In particular embodiments, the TCRP and FCRP comprise any of the TCRP and FCRP described in the embodiments and examples described herein and those illustrated with respect to FIGURES 3-7.

[0131] At step 1214, the wireless device may determine a distance between the wireless device and a satellite providing the NTN cell. The wireless device may compare the determined distance to the distance from the TCRP / FCRP to the satellite providing the NTN cell to make determination as to whether the wireless device should access the NTN cell. For example, in particular embodiments, the wireless device may verify that the distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell before accessing the NTN cell. As another example, if the wireless device detects that its distance to the satellite providing the NTN cell is smaller than the distance from the TCRP to the satellite providing the NTN cell (e.g., when the wireless device has an estimate of its location based on GNSS or other means of positioning), the wireless device may abstain from accessing the satellite access network.

[0132] In some embodiments, the wireless device may verify that the distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before accessing the NTN cell. For example, a wireless device that is closer to the satellite providing the NTN cell than the TCRP is allowed to transmit if the absolute value of the difference between the TCRP -satellite round trip time (RTT) and the UE- satellite RTT is smaller than a certain threshold value.

[0133] In particular embodiments, the threshold value is based on a cyclic prefix (CP) value used by the wireless device in the NTN cell. For example, the threshold value may be smaller than the CP or smaller than a certain fraction (e.g., half) of the CP.

[0134] In some embodiments, the CP in the condition is the CP of the random access preamble and the wireless device is allowed to transmit a random access preamble (and possibly random access Msg3) and after that the network node can adjust the wireless device timing advance (TA) to its correct negative value using relative timing advance adjustments.

[0135] In some embodiments, the CP in the condition is the CP for regular non-random access transmissions, e.g., physical uplink shared channel (PUSCH) and physical uplink control channel (PUCCH) transmissions.

[0136] At step 1216, the wireless device determines an uplink pre-compensation for timing based on the TCRP. For example, the wireless device uses the TCRP instead of its true position to perform its TA offset estimate.

[0137] At step 1218, the wireless device determines an uplink pre-compensation for Doppler offset based on the FCRP. For example, the wireless device uses the FCRP instead of its true position to perform its Doppler offset estimate.

[0138] At step 1220, the wireless device transmits an uplink transmission using the determined timing pre-compensation and Doppler pre-compensation.

[0139] Modifications, additions, or omissions may be made to method 1200 of FIGURE 12. Additionally, one or more steps in the method of FIGURE 12 may be performed in parallel or in any suitable order.

[0140] FIGURE 13 is a flowchart illustrating an example method 1300 in a network node, according to certain embodiments. In particular embodiments, one or more steps of FIGURE 13 may be performed by network node 300 described with respect to FIGURE 10. The network node is comprised in an NTN.

[0141] The method may begin at step 1312, where the network node (e.g., network node 300) obtains a FCRP and a TCRP for an NTN cell. The network node may obtain the FCRP and the TCRP from another network node, such as a core network node or a provisioning network node. The FCRP and TCRP are described in more detail with respect to step 1212 of FIGURE 12 and with respect to the embodiments and examples described herein.

[0142] At step 1314, the network node may determine a distance between the wireless device and a satellite providing the NTN cell. In particular embodiments, the network node determines a distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell and bars the wireless device from accessing the NTN cell.

[0143] In particular embodiments, the network node determines a distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before allowing the wireless device to access the NTN cell.

[0144] Examples of threshold values are described in more detail with respect to step 1214 of FIGURE 12 and in the embodiments and examples described herein.

[0145] At step 1316, the network node determines a downlink pre-compensation for timing based on the TCRP. For example, the network node determines a downlink pre-compensation for timing based on the location of the TCRP instead of the actual location of the wireless device.

[0146] At step 1318, the network node determines a downlink pre-compensation for Doppler offset based on the FCRP. For example, the network node determines a downlink precompensation for Doppler offset based on the location of the FCRP instead of the actual location of the wireless device.

[0147] At step 132, the network node transmits a downlink transmission to the wireless device using the determined timing pre-compensation and Doppler pre-compensation.

[0148] Modifications, additions, or omissions may be made to method 1300 of FIGURE 13. Additionally, one or more steps in the method of FIGURE 13 may be performed in parallel or in any suitable order.

[0149] Modifications, additions, or omissions may be made to the methods disclosed herein without departing from the scope of the invention. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order.

[0150] The foregoing description sets forth numerous specific details. It is understood, however, that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

[0151] References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0152] Although this disclosure has been described in terms of certain embodiments, alterations and permutations of the embodiments will be apparent to those skilled in the art. Accordingly, the above description of the embodiments does not constrain this disclosure. Other changes, substitutions, and alterations are possible without departing from the scope of this disclosure, as defined by the claims below.

[0153] Some example embodiments follow.A Embodiments A method performed by a user equipment for uplink in a non-terrestrial network (NTN), the method comprising:- obtaining a frequency common reference point (FCRP) and a timing common reference point (TCRP) for a NTN cell;- determining an uplink pre-compensation for timing based on the TCRP;- determining an uplink pre-compensation for Doppler offset based on the FCRP; and- transmitting an uplink transmission using the determined timing precompensation and Doppler pre-compensation. The method of the previous embodiment, wherein the FCRP is located at a center of the NTN cell. The method of any one of the previous embodiments, wherein the TCRP is located at a cell edge closest to a satellite providing the NTN cell. The method of any one of the previous embodiments, wherein the FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell. The method of any one of the previous embodiments, wherein the TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a user equipment in the cell and the satellite. The method of any one of the previous embodiments, wherein the TCRP is located at a nadir point in the NTN cell. The method of any one of the previous embodiments, wherein at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves. The method of the previous embodiment, wherein the TCRP moves to maintain a position in a middle of a cone formed by a beam from a satellite providing the NTNcell.9. The method of any one of the previous embodiments, wherein at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface.10. The method of the previous embodiment, wherein the TCRP is located at maximum user equipment altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell and the FCRP is located at half the maximum user equipment altitude on an axis of the cone defined by the beam.11. The method of any one of the previous embodiments, further comprising determining the distance between the user equipment and a satellite providing the NTN cell is larger than the distance from the TCRP to the satellite before accessing the NTN cell.12. The method of any one of the previous embodiments, further comprising determining the distance between the user equipment and a satellite providing the NTN cell is within a threshold a value of the distance from the TCRP to the satellite before accessing the NTN cell.13. The method of the previous embodiment, wherein the threshold value is equal to a cyclic prefix value used by the user equipment in the NTN cell.14. The method of any one of the previous embodiments, wherein the TCRP and FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel (PRACH) occasion and the method further comprises obtaining a second TCRP and second FCRP associated with a second PRACH occasion.15. A method performed by a user equipment, the method comprising:- any of the user equipment steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.16. The method of the previous embodiment, further comprising one or more additional user equipment steps, features or functions described above.Group B Embodiments17. A method performed by a network node for downlink in a non-terrestrial network (NTN), the method comprising:- obtaining a frequency common reference point (FCRP) and a timing common reference point (TCRP) for a user equipment (UE) in a NTN cell;- determining a downlink pre-compensation for timing based on the TCRP;- determining a downlink pre-compensation for Doppler offset based on the FCRP; and- transmitting a downlink transmission to the UE using the determined timing pre-compensation and Doppler pre-compensation.18. The method of the previous embodiment, wherein the FCRP is located at a center of the NTN cell.19. The method of any one of the previous two embodiments, wherein the TCRP is located at a cell edge closest to a satellite providing the NTN cell.20. The method of any one of the previous three embodiments, wherein the FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell.21. The method of any one of the previous four embodiments, wherein the TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a user equipment in the cell and the satellite.22. The method of any one of the previous five embodiments, wherein the TCRP is located at a nadir point in the NTN cell.23. The method of any one of the previous six embodiments, wherein at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves.24. The method of the previous embodiment, wherein the TCRP moves to maintain a position in a middle of a cone formed by a beam from a satellite providing the NTNcell. The method of any one of the previous eight embodiments, wherein at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface. The method of the previous embodiment, wherein the TCRP is located at maximum user equipment altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell and the FCRP is located at half the maximum user equipment altitude on an axis of the cone defined by the beam. The method of any one of the previous embodiments, further comprising determining the distance between a user equipment and a satellite providing the NTN cell is less than the distance from the TCRP to the satellite and barring the user equipment from accessing the NTN cell. The method of any one of the previous embodiments, further comprising determining the distance between a user equipment and a satellite providing the NTN cell is within a threshold a value of the distance from the TCRP to the satellite before allowing the user equipment to access the NTN cell. The method of the previous embodiment, wherein the threshold value is equal to a cyclic prefix value used by the user equipment in the NTN cell. The method of any one of the previous embodiments, wherein the TCRP and the FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel (PRACH) occasion and the method further comprises obtaining a second TCRP and second FCRP associated with a second PRACH occasion. A method performed by a network node, the method comprising:- any of the steps, features, or functions described above with respect to a network node, either alone or in combination with other steps, features, or functions described above. The method of the previous embodiment, further comprising one or more additionalnetwork node steps, features or functions described above.C Embodiments33. A user equipment, comprising: processing circuitry configured to perform any of the steps of any of the Group A embodiments; and power supply circuitry configured to supply power to the processing circuitry.34. A network node, the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B embodiments; power supply circuitry configured to supply power to the processing circuitry.35. A user equipment (UE), the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS:

1. A method performed by a wireless device capable of communicating with a non-terrestrial network, NTN, the method comprising: obtaining (1212) a frequency common reference point, FCRP, and a timing common reference point, TCRP, for an NTN cell; determining (1216) an uplink pre-compensation for timing based on the TCRP; determining (1218) an uplink pre-compensation for Doppler offset based on the FCRP; and transmitting (1220) an uplink transmission using the determined timing precompensation and Doppler pre-compensation.

2. The method of claim 1 , wherein the FCRP is located at a center of the NTN cell.

3. The method of any one of claims 1 -2, wherein the TCRP is located at a cell edge closest to a satellite providing the NTN cell.

4. The method of any one of claims 1-3, wherein the FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell.

5. The method of any one of claims 1-4, wherein the TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a wireless device in the cell and the satellite providing the NTN cell.

6. The method of any one of claims 1-5, wherein the TCRP is located at a nadir point in the NTN cell.

7. The method of any one of claims 1-6, wherein at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves.

8. The method of claim 7, wherein the TCRP moves to maintain a position in amiddle of a cone formed by a beam from a satellite providing the NTN cell.

9. The method of any one of claims 1-8, wherein at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface.

10. The method of claim 9, wherein the TCRP is located at a maximum wireless device altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell, and the FCRP is located at half the maximum wireless device altitude on an axis of the cone defined by the beam.

11. The method of any one of claims 1-10, further comprising determining (1214) a distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell before accessing the NTN cell.

12. The method of any one of claims 1-11, further comprising determining (1214) a distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before accessing the NTN cell.

13. The method of claim 12, wherein the threshold value is based on a cyclic prefix value used by the wireless device in the NTN cell.

14. The method of any one of claims 1-13, wherein the FCRP and the TCRP are located at the same position.

15. The method of any one of claims 1-14, wherein the TCRP and FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel, PRACH, occasion and the method further comprises obtaining (1212) a second TCRP and second FCRP associated with a second PRACH occasion.

16. The method of any one of claims 1-15, wherein obtaining the FCRP and the TCRP further comprises obtaining trajectory information for at least one of the FCRP and the TCRP.

17. A wireless device (200) capable of capable of communicating with a nonterrestrial network, NTN, the wireless device comprising processing circuitry (202) operable to: obtain a frequency common reference point, FCRP, and a timing common reference point, TCRP, for an NTN cell; determine an uplink pre-compensation for timing based on the TCRP; determine an uplink pre-compensation for Doppler offset based on the FCRP; and transmit an uplink transmission using the determined timing pre-compensation and Doppler pre-compensation.

18. The wireless device of claim 17, the processing circuitry further operable to perform the steps of any one of claims 2-16.

19. A method performed by a network node comprised in a non-terrestrial network, NTN, the method comprising: obtaining (1312) a frequency common reference point, FCRP, and a timing common reference point, TCRP, for a wireless device in an NTN cell; determining (1316) a downlink pre-compensation for timing based on the TCRP; determining (1316) a downlink pre-compensation for Doppler offset based on the FCRP; and transmitting (1320) a downlink transmission to the wireless device using the determined timing pre-compensation and Doppler pre-compensation.

20. The method of claim 19, wherein the FCRP is located at a center of the NTN cell.

21. The method of any one of claims 19-20, wherein the TCRP is located at a cell edge closest to a satellite providing the NTN cell.

22. The method of any one of claims 19-21, wherein the FCRP is located at a point that minimizes the maximum error in the Doppler pre-compensation across the NTN cell.

23. The method of any one of claims 19-22, wherein the TCRP is located at a point in the NTN cell where the distance between the TCRP and a satellite providing the NTN cell is less than a distance between a wireless device in the cell and the satellite providing the NTN cell.

24. The method of any one of claims 19-23, wherein the TCRP is located at a nadir point in the NTN cell.

25. The method of any one of claims 19-24, wherein at least one of the TCRP and the FCRP move as a satellite providing the NTN cell moves.

26. The method of claim 25, wherein the TCRP moves to maintain a position in a middle of a cone formed by a beam from a satellite providing the NTN cell.

27. The method of any one of claims 19-26, wherein at least one of the TCRP and the FCRP is located at an altitude above the Earth’s surface.

28. The method of claim 27, wherein the TCRP is located at a wireless device altitude and on a surface of a cone defined by a beam from a satellite providing the NTN cell, and the FCRP is located at half the maximum wireless device altitude on an axis of the cone defined by the beam.

29. The method of any one of claims 19-28, further comprising determining (1314) a distance between the wireless device and a satellite providing the NTN cell is larger than a distance from the TCRP to the satellite providing the NTN cell and barring the wireless device from accessing the NTN cell.

30. The method of any one of claims 19-29, further comprising determining (1314) a distance between the wireless device and a satellite providing the NTN cell is within a threshold value of a distance from the TCRP to the satellite before allowing the wireless device to access the NTN cell.

31. The method of claim 30, wherein the threshold value is based on a cyclic prefix value used by the wireless device in the NTN cell.

32. The method of any one of claims 19-31, wherein the FCRP and the TCRP are located at the same position.

33. The method of any one of claims 19-32, wherein the TCRP and FCRP comprise a first TCRP and a first FCRP, respectively, associated with a first physical random access channel, PRACH, occasion and the method further comprises obtaining (1312) a second TCRP and second FCRP associated with a second PRACH occasion.

34. The method of any one of claims 19-33, wherein obtaining the FCRP and the TCRP further comprises obtaining trajectory information for at least one of the FCRP and the TCRP.

35. A network node (300) comprised in a non-terrestrial network, NTN, the network node comprising processing circuitry (302) operable to: obtain a frequency common reference point, FCRP, and a timing common reference point, TCRP, for a wireless device (200) in an NTN cell; determine a downlink pre-compensation for timing based on the TCRP; determine a downlink pre-compensation for Doppler offset based on the FCRP; and transmit a downlink transmission to the wireless device using the determined timing pre-compensation and Doppler pre-compensation.

36. The network node of claim 35, the processing circuitry further operable to perform the steps of any one of claims 20-34.

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