Feeder Link and Common Delay Signaling in NTN

Abstract

An embodiment provides a user equipment of a wireless communication system, the user equipment configured to communicate with a base station of the wireless communication system via a satellite of the wireless communication system, the user equipment configured to receive control information from the base station via the satellite or from another user equipment of the wireless communication system via a sidelink, the control information signaling at least one parameter for parameterizing a non-linear function, the parameterized non-linear function being: a satellite and one of a base station or a satellite gateway of a wireless communication system; A satellite and a geographical reference point of a wireless communication system; between a first reference point and a second reference point, the first reference point having a fixed relationship to a satellite and the second reference point having a fixed relationship to one of a base station, a satellite gateway, or a user equipment; Depending on the position of the satellite, it describes the round trip time or the delay time that elapses.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of wireless communication, and more specifically, to wireless communication between a base station gNB and a user equipment via a satellite / non-terrestrial network, NTN. Some embodiments relate to feeder link signaling and common delays in NTN.

Summary of the Invention

[0002] As shown in FIG. 1(a), FIG. 1 is a schematic diagram of an example of a terrestrial wireless network 100 including a core network 102 and one or more radio access networks RAN 1 , RAN 2 ,...RAN N . FIG. 1(b) is a schematic diagram of an example of a radio access network RAN 1 that may include one or more base stations gNB 5 to gNB n , each providing services to a specific area surrounding the base station, schematically represented by its respective cells 106 1 to 106 5 . The base station is provided to provide services to users within the cell. The term base station, BS, refers to gNB in a 5G network, eNB in UMTS / LTE / LTE-A / LTE-A Pro, and simply BS in other mobile communication standards. A user can be a fixed device or a mobile device. The wireless communication system can be accessed by a mobile or fixed IoT device connected to the base station or the user. Mobile devices or IoT devices include physical devices, ground vehicles such as robots or cars, aircraft such as manned or unmanned aircraft (UAVs), the latter also called drones, buildings, and electronic devices, software, sensors, actuators, etc. embedded therein, as well as other items or devices that also have network connectivity so that these devices can collect and exchange data across the entire existing network infrastructure. FIG. 1(b) shows an exemplary diagram of five cells, although RANn may contain more or fewer such cells, and the RAN n 1(b) may include only one base station. 2 Located in the base station gNB 2 Two user equipments, also called user equipments, UEs, are served by 1 and UE 2 Another user UE 3 is a base station gNB 4 Cell 106 served by 4 As shown in the arrow 108 1 , 108 2 and 108 3 is the user UE 1 , U.E. 2 and UE 3 From base station gNB 2 , gNB 4 or to transmit data to the base station gNB 2 , gNB 4 From User UE 1 , U.E. 2 , U.E. 3 1(b) also shows a schematic diagram of an uplink / downlink connection for transmitting data to a cell 106. 4 Two IoT devices 110 1 and 110 2 , which may be fixed or mobile devices. 1 Arrow 112 1 As represented diagrammatically by 4 The IoT device 110 accesses the wireless communication system via the 2 Arrow 112 2 As represented diagrammatically by 3 Each base station gNB 1 From gNB 5 , for example, via the S1 interface, 1 From 114 5May be connected to the core network 102 via these, which are schematically represented in FIG. 1(b) by the arrows pointing to the "core". The core network 102 may be connected to one or more external networks. Further, each base station gNB 1 from gNB 5 Some or all of may be connected to each other via, for example, the S1 or X2 interface or XN interface of NR and each backhaul link 116 1 from 116 5 via these, which are schematically represented in FIG. 1(b) by the arrows pointing to the "gNB".

[0003] For data transmission, a physical resource grid may be used. The physical resource grid may include a set of resource elements to which various physical channels and physical signals are mapped. For example, physical channels may include physical downlink, uplink, and sidelink shared channels (PDSCH, PUSCH, PSSCH) that carry user-specific data, also referred to as downlink, uplink, and sidelink payload data, such as a physical broadcast channel (PBCH) that carries a master information block (MIB), a physical downlink shared channel (PDSCH) that carries a system information block (SIB), physical downlink, uplink, and sidelink control channels (PDCCH, PUCCH, PSSCH) that carry downlink control information (DCI), uplink control information (UCI), and sidelink control information (SCI). In the case of the uplink, the physical channel, or more precisely the transport channel according to 3GPP (registered trademark, the same hereinafter), may further include a physical random access channel (PRACH or RACH) used by the UE to access the network once the UE is synchronized and has obtained the MIB and SIB. Physical signals may include reference signals or symbols (RS), synchronization signals, etc. The resource grid may include a frame or radio frame having a specific duration in the time domain and a given bandwidth in the frequency domain. The frame may have a certain number of subframes of a predetermined length, e.g., 1 ms. Each subframe may include one or more slots of 12 or 14 OFDM symbols depending on the length of the cyclic prefix (CP). All OFDM symbols may be used only for DL or UL or a subset thereof when using, for example, a short transmission time interval (sTTI) or a mini-slot / non-slot-based frame structure consisting of only a few OFDM symbols.

[0004] The wireless communication system can be an orthogonal frequency division multiplexing (OFDM) system, an orthogonal frequency division multiple access (OFDMA) system, or any other IFFT-based signal with or without cyclic prefix (CP), such as DFT-s-OFDM, and can be any single-tone system or multi-carrier system that uses frequency division multiplexing. Other waveforms such as non-orthogonal waveforms for multiple access, for example, filter bank multi-carrier (FBMC), generalized frequency division multiplexing (GFDM), or universal filtered multi-carrier (UFMC) can be used. The wireless communication system can operate according to, for example, the LTE-Advanced pro standard or the NR (5G), New Radio, standard.

[0005] The wireless network or communication system illustrated in FIG. 1 can be a heterogeneous network with different overlay networks, for example, a macro cell network with each macro cell including a macro base station such as gNB 1 from gNB 5 to gNB, and a network of small cell base stations (not shown in FIG. 1) such as femto or pico base stations.

[0006] In addition to the above-mentioned terrestrial wireless network, there is also a non-terrestrial wireless communication network including satellite-mounted transceivers such as satellites and / or aircraft-mounted transceivers such as unmanned aircraft systems. The non-terrestrial wireless communication network or system can operate in the same manner as the terrestrial system described above with reference to FIG. 1 according to, for example, the LTE-Advanced Pro standard or the 5G (NR), new radio, standard.

[0007] In a mobile communication network, such as the networks described above with reference to FIG. 1, like an LTE or 5G / NR network, there may be UEs that communicate directly with each other via one or more sidelink (SL) channels, for example, using the PC5 interface. UEs that communicate directly with each other via the sidelink may include vehicles that communicate directly with other vehicles (V2V communication), vehicles that communicate with other entities of the wireless communication network (V2X communication), for example, roadside entities such as traffic lights, traffic signs or pedestrians. Other UEs may not be vehicle-related UEs and may include any of the above devices. Such devices can also communicate directly with each other (D2D communication) using the SL channel.

[0008] Considering two UEs that communicate directly with each other via the sidelink, both UEs may be served by the same base station, and as a result, the base station may provide sidelink resource allocation configuration or assistance to the UEs. For example, both UEs may be within the coverage area of a base station, like one of the base stations illustrated in FIG. 1. This is called the "in-coverage" scenario. Another scenario is called the "out-of-coverage" scenario. By "out-of-coverage", it does not mean that the two UEs are not within one of the cells illustrated in FIG. 1. Rather, these UEs may not be connected to a base station so that the UEs do not receive any sidelink resource allocation configuration or assistance from the base station, for example, not in the RRC connected state, and / or may be connected to a base station, but for one or more reasons, the base station may not provide sidelink resource allocation configuration or assistance to the UEs, and / or note that it may be connected to a base station that does not support NR V2X services, for example, a GSM, UMTS, LTE base station.

[0009] For example, considering two UEs that communicate directly with each other via sidelink using a PC5 interface, one of the UEs may be connected to the BS and relay information from the BS to the other UE via the sidelink interface. The relaying may be performed in the same frequency band (in-band relaying) or in a different frequency band (out-of-band relaying). In the first case, the communication on Uu and on the sidelink can be separated using different time slots, such as in a time division duplex (TDD) system.

[0010] Figure 2 is a schematic diagram of an in-coverage scenario where two UEs communicating directly with each other are both connected to a base station. The base station gNB basically has a coverage area schematically represented by a circle 200 corresponding to the cell schematically shown in FIG. 1. The UEs communicating directly with each other include a first vehicle 202 and a second vehicle 204 both within the coverage area 200 of the base station gNB. Vehicles 202 and 204 are both connected to the base station gNB and, in addition, they are directly connected to each other via the PC5 interface. The scheduling and / or interference management of V2V traffic is assisted by the gNB via control signals over the Uu interface, which is the radio interface between the base station and the UEs. In other words, the gNB provides SL resource allocation configuration or assistance to the UEs, and the gNB allocates resources used for V2V communication via the sidelink. This configuration is also referred to as mode 1 configuration in NR V2X or mode 3 configuration in LTE V2X.

[0011] Figure 3 is a schematic diagram of an out-of-coverage scenario where the UEs that physically exist within a cell of a wireless communication network may or may not be connected to a base station and directly communicate with each other, or some or all of the UEs that directly communicate with each other are connected to a base station, but the base station does not provide SL resource allocation configuration or assistance. Three vehicles 206, 208, and 210 are shown to be directly communicating with each other via a sidelink, for example, using a PC5 interface. Scheduling of V2V traffic and / or interference management is based on algorithms implemented between the vehicles. This configuration is also referred to as a mode 2 configuration in NR V2X or a mode 4 configuration in LTE V2X. As described above, the scenario of Figure 3, which is an out-of-coverage scenario, does not necessarily mean that each mode 2 UE (within NR) or mode 4 UE (within LTE) is outside the coverage 200 of the base station. Rather, it means that each mode 2 UE (within NR) or mode 4 UE (within LTE) is not served by the base station, not connected to the base station in the coverage area, or, if connected to the base station, has not received SL resource allocation configuration or assistance from the base station. Therefore, there may be a situation where, in addition to the UEs 202, 204 in NR mode 1 or LTE mode 3 within the coverage area 200 shown in Figure 2, there are also UEs 206, 208, 210 in NR mode 2 or LTE mode 4.

[0012] Of course, as will be apparent from the descriptions of Figures 4 and 5, it is possible that the first vehicle 202 is covered by a gNB, i.e., connected to the gNB via Uu, where the second vehicle 204 is not covered by the gNB and is only connected to the first vehicle 202 via a PC5 interface, or the second vehicle is connected to the first vehicle 202 via a PC5 interface but is also connected to another gNB via Uu.

[0013] Figure 4 is a schematic diagram of a scenario where two UEs communicating directly with each other, and only one of the two UEs is connected to a base station. The base station gNB basically has a coverage area schematically represented by a circle 200 corresponding to the cell schematically shown in FIG. 1. The UEs communicating directly with each other include a first vehicle 202 and a second vehicle 204, and only the first vehicle 202 is within the coverage area 200 of the base station gNB. Both vehicles 202 and 204 are directly connected to each other via the PC5 interface.

[0014] Figure 5 is a schematic diagram of a scenario where two UEs communicating directly with each other are connected to different base stations. The first base station gNB 1 has a coverage area schematically represented by a first circle 200 1 and the second base station gNB 2 has a coverage area schematically represented by a second circle 200 2 The UEs communicating directly with each other include a first vehicle 202 and a second vehicle 204. The first vehicle 202 is within the coverage area 200 1 of the first base station gNB 1 and is connected to the first base station gNB via the Uu interface 1 The second vehicle 204 is within the coverage area 200 2 of the second base station gNB 2 and is connected to the second base station gNB via the Uu interface 2 .

[0015] In the wireless communication system as described above, in 3GPP, a new work item (WI) has been started to introduce a non-terrestrial network (NTN). Within this WI, the technical feasibility of various satellite systems (GEO, MEO, LEO, etc.) and high-altitude platforms (HAPS), which are part of the 3GPP Rel-17 network architecture, is being studied.

[0016] One of the unique features of NTN is the large propagation delay experienced between the user equipment (UE) and the satellite system and, as a result, between the UE and the gNB. Typically, the propagation delay in terrestrial systems is less than 1 ms. However, in NTN, the propagation delay can range from several milliseconds to hundreds of milliseconds depending on the altitude of the spaceborne or airborne platform and the payload type in NTN, as shown as an example in Figure 6.

[0017] Specifically, Figure 6 shows a schematic block diagram of a wireless communication system comprising a gNB connected to an NTN satellite that moves via a satellite gateway to serve cells where two UEs are located. Thereby, in Figure 6, t1 and t2 illustrate the times when the satellite is located at the corresponding positions. Clearly, the movement of the satellite causes a change in the round-trip time or delay between the gNB and the corresponding UE.

[0018] Therefore, starting from the above, in order to be able to cope with the large propagation delay in NTN, one or more RAN procedures (e.g., from the physical layer to the upper layers) need to be enhanced, improved, and / or changed.

[0019] Note that the information in the above section is only for enhancing the understanding of the background of the present invention and may thus include information that does not form part of the prior art and may already be known to those skilled in the art.

[0020] Embodiments of the present invention are described herein with reference to the accompanying drawings.

Brief Description of the Drawings

[0021]

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Figure 6

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Figure 12

Embodiments for Carrying Out the Invention

[0022] In the following description, equivalent or identical elements or elements having equivalent or identical functions are denoted by equivalent or identical reference numerals.

[0023] In the following description, in order to provide a more thorough description of embodiments of the present invention, a plurality of details are set forth. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention. In addition, the features of different embodiments described herein below may be combined with each other unless otherwise specified.

[0024] As already shown in the introduction section, in 3GPP, a new work item (WI) has been initiated to introduce non-terrestrial networks (NTN). Within this WI, the technical feasibility of various satellite systems (GEO, MEO, LEO, etc.) and high-altitude platforms (HAPS), which are part of the 3GPP Rel-17 network architecture, is being studied.

[0025] One of the unique characteristics of NTN is the large propagation delay experienced between the user equipment (UE) and the satellite system and, as a result, between the gNB. Typically, the propagation delay in terrestrial systems is less than 1 ms. However, in NTN, the propagation delay can range from several milliseconds to hundreds of milliseconds depending on the altitude and payload type of the spaceborne or airborne platform in NTN.

[0026] In order to be able to cope with the large propagation delay in NTN, one or more RAN procedures, for example, need to be changed from the physical layer to the upper layers [1], [2].

[0027] Below, first, some examples of procedures affected by the large propagation delay in NTN will be described. Second, the related components of the propagation delay in NTN, namely, UE-specific delay and UE-common delay, will be described.

[0028] Procedures Affected by NTN Propagation Delay From the perspective of RAN2, the 4-step random access channel (RACH) procedure and the 2-step RACH procedure are affected. In particular, in RAN2 #112e[5], it was agreed to compensate for the start of the "ra-ResponseWindow" and "msgB-ResponseWindow" by the user equipment (UE)-gNB round-trip time (RTT). This agreement is specified below.

[0029]

Table 1

[0030] In particular, the ra-ResponseWindow and msgB-ResponseWindow are, respectively, specific time windows in which the UE expects to receive message 2 (MSG2) from the gNB, also called the response message, for the preamble transmission in message 1 (MSG1) in the 4-step and 2-step random access procedures.

[0031] Another procedure in RAN2 that is affected by the UE-gNB delay (or RTT) is related to HARQ. Specifically, in RAN2 #112eqe[5]-[6], for the case of NTN UEs with pre-compensation capabilities, it has been agreed that the drx-HARQ-RTT-TimerDL is offset by the UE-specific RTT (UE-gNB delay). This agreement is specified below.

[0032]

Table 2

[0033] From the perspective of RAN1, one of the important procedures affected by the large propagation delay in NTN is the timing advance procedure [2]. In the timing advance procedure, after estimating the UE's RTT, the gNB sends a timing advance command to adjust the UE's uplink transmission timing. Clearly, the value of the timing advance command is related to the UE-gNB RTT.

[0034] Another procedure specific to NTN is the feeder link switching procedure [2]. In the feeder link switching procedure, the satellite providing service to the UEs within a cell is switched to a new satellite, and as a result, the feeder link, i.e., the communication link between the satellite and the gateway, must be switched. Since the new satellite has a different geographical location compared to the old serving satellite, the UE-gNB RTT is changed and the delay of the feeder link must be signaled to the UE.

[0035] From the above description, it can be observed that there are several procedures in NTN and it is particularly necessary to enhance through the UE-gNB RTT / delay.

[0036] In the following, the components of the UE-gNB RTT / delay will be described in more detail.

[0037] UE-gNB RTT / Delay Generally, the end-to-end delay experienced by an NTN UE can be divided into two main parts, namely UE-specific delay and UE-common delay. The calculation of both UE-specific and UE-common delays depends on the selection of a so-called reference point (RP). In particular, the RP is defined as the point at which the downlink frame and the uplink frame are aligned after the UE applies the TA command in the RACH procedure. As a result, the value of TA is calculated with respect to the RP. Usually, the RP can be selected to be at a point located in the gNB, the feeder link, the satellite, or the service link. In RAN1, the selection of the RP is arbitrary and must be under the control of the network, and it is determined that at least the gNB should include the RP (see Figure 6). For example, if the RP is selected to be at the satellite (RP3 in Figure 6) and the UE applies the TA command, the uplink frame and the downlink frame are aligned at the satellite, and the gNB needs to handle the timing of the unaligned uplink frame and downlink frame and apply post-timing compensation based on the RTT of the feeder link.

[0038] On one hand, the selection of the RP at the gNB (RP1 in FIG. 6) brings about frame timing in the uplink and downlink that are aligned at the gNB. Considering the definition of the above reference points, the UE-specific delay and the UE-common delay can be defined as follows.

[0039] The UE-specific delay can be defined as the delay of the UE to the satellite. When the RP is defined to be located on the service link, the UE-specific delay can be defined as the delay of the UE to the RP. In Rel17, it is assumed that the NTN UE is equipped with a GNSS unit. As a result, the GNSS-equipped UE can estimate the distance to the satellite with the assistance of satellite ephemeris and calculate the UE-Satellite delay. When the RP is selected, for example, as in RP 4 in FIG. 6 on the service link, the UE-specific delay can be evaluated after subtracting the delay from the Satellite to the RP (Satellite-RP delay) from the UE-Satellite delay.

[0040] The UE-common delay can be defined as the delay of the satellite to the RP (Satellite-RP). Depending on the location of the RP, the UE-common delay can be evaluated as follows.

[0041] ○ It can incorporate the partial delay of the feeder link when the RP is selected on the feeder link, for example, as in RP 2 in FIG. 6.

[0042] ○ It can be set to zero. This is the case when the RP is selected to be on the satellite, for example, as in RP 3 in FIG. 6.

[0043] ○ It can incorporate the partial delay of the service link when the RP is selected on the service link, for example, as in RP 4 in FIG. 6.

[0044] ○ For example, when RP is selected to be at the gNB as in RP 1 of FIG. 6, it can capture the overall feeder link delay, i.e., the gNB - gateway - satellite delay.

[0045] In addition to the common delay, the feeder link delay can be defined as the delay of the gNB with respect to RP. Note that for the case of RP on the service link, the feeder link delay can be defined as the delay of the gNB to the satellite. Some of the procedures considered at the beginning of this section may require knowledge of the end - to - end UE - gNB delay. Considering the definitions of UE - specific and UE - common delays as above, except for the case of RP at the gNB, for the calculation of the UE - gNB delay, signaling of both the common delay from the network to the UE and the feeder link delay may be required.

[0046] Thus, in the following description, note that for the sake of brevity of presentation and as an example, the feeder link delay and the common delay are referred to together as the common delay. In other words, in the following description, it is exemplarily assumed that RP is located at the gNB. However, the procedures described in the following sections are equally valid for other choices of RP.

[0047] Also, due to the movement of the satellite, the common delay changes over time. For example, in FIG. 6, the distance from the satellite to the gateway decreases from TIFF0007690601000003.tif74 to TIFF0007690601000004.tif74, leading to a change in the value of the common delay. Therefore, the updated value of the common delay needs to be signaled to the UE to update the old UE - gNB RTT.

[0048] Considering the above description, the embodiments described below rely on the signaling of the common delay in NTN.

[0049] Generally, different options are available for the signaling of the common delay.

[0050] The first option is network-centric, and the gNB signals the absolute value of the common delay to the UE. However, due to the time-varying nature of the common delay, this approach requires a large signaling overhead, especially for LEO and VLEO satellites, as frequent updates of the common delay value are required.

[0051] Another option, which is both network-centric and UE-centric, relies on the autonomous calculation of the common delay on the UE side via a given function and the signaling (or updating) of the function parameters from the gNB to the UE. This mechanism has been proposed in [3] for TA and handover procedures. However, the details of the signaling are not described in [3].

[0052] Also, in [4], the "U"-shaped characteristic of the common delay (feeder link RTT) is approximated via a piecewise linear function (see Figure 7 below). Specifically, Figure 7 shows the feeder link RTT as a function of time [4]. Thereby, the vertical axis illustrates the feeder link RTT in ms units, and the horizontal axis illustrates the time in s units.

[0053] Next, it is assumed that the UE autonomously updates the value of the common delay via the linear function, and the gNB provides the UE with the parameters of the linear function, i.e., the constant term plus the drift value that describes the gradient of the linear function.

[0054] Obviously, the approach proposed above reduces the signaling overhead compared to the network-centric first option introduced above. However, there is a trade-off between accuracy and signaling overhead. To have an accurate approximation of the actual feeder link delay / RTT, the number of piecewise linear functions increases, thereby increasing the signaling overhead.

[0055] Hereinafter, embodiments of the present invention will be described that further reduce the signaling overhead and improve the accuracy of the common delay estimation.

[0056] Accordingly, embodiments of the present invention can be implemented in a wireless communication system or network as shown in the figures from FIGS. 1 to 6, including a plurality of communication devices such as a base station, a transceiver such as a gNB, and a user equipment, UE, that communicates with the transceiver via a satellite / non-terrestrial network, NTN. FIG. 8 shows a plurality of communication devices 302 such as a UE that communicate with a transceiver 300 via a transceiver 300 and a satellite / non-terrestrial network 304, such as a base station 1 from 302 n is a schematic diagram of a wireless communication system comprising. The transceiver 300 can include one or more antennas, a signal processor 300a, and a transceiver unit 300b. UE 302 1 from 302 n can include one or more antennas, a signal processor 302a 1 from 302a n , a transceiver unit 302b 1 from 302b n . The satellite 304 can include one or more antennas, a signal processor 304a, and a transceiver unit 304b. The base station 200 and / or one or more UEs 202 and / or the satellite 304 can operate according to the teachings of the present invention described herein.

[0057] Embodiments provide a user equipment of a wireless communication system [e.g., 5G / new radio, NR], the user equipment being configured to communicate with a base station [e.g., gNB] of the wireless communication system via a satellite of the wireless communication system, the user equipment being configured to receive control information from the base station via the satellite or from another user equipment of the wireless communication system via a sidelink, the control information signaling at least one parameter [e.g., one or more from parameters (a, b, c)] for parameterizing a non-linear function, and the parameterized non-linear function [e.g., the parameterized version of the non-linear function] describes the passage [e.g., variation] of the round-trip time or delay time between the following One from a satellite and a base station or a satellite gateway of a wireless communication system A geographical reference point of a satellite and a wireless communication system A first reference point and a second reference point, where the first reference point has a fixed relationship [e.g., distance] with respect to the satellite, and the second reference point has a fixed relationship [e.g., distance] with respect to one from a base station, a satellite gateway, or a user equipment, being the first reference point and the second reference point

[0058] [For example, when the satellite is within the range of a user equipment and / or a satellite gateway] It is dependent on the position of the satellite [e.g., a user equipment or a satellite gateway of a wireless communication system with respect to a geographical reference point].

[0059] In an embodiment, the user equipment is configured to time-synchronize communication [e.g., transmission and / or reception] [e.g., uplink / downlink for] with a base station using a parameterized non-linear function.

[0060] In an embodiment, the user equipment is configured to determine a round-trip time or a delay time of a specific [e.g., current] time [e.g., slot] using a parameterized non-linear function, and the user equipment is configured to time-synchronize communication with a base station at a specific time based on the determined round-trip time or delay time.

[0061] In an embodiment, the non-linear function describes the passage of a round-trip time or a delay time between a satellite and one from a base station or a satellite gateway, and the round-trip time or the delay time is a feeder link round-trip time or a feeder link delay time.

[0062] In an embodiment, the non-linear function describes the passage of a round-trip time or a delay time between a satellite and a geographical reference point, and the round-trip time or the delay time is a common round-trip time or a common delay time.

[0063] In an embodiment, the geographical reference point is A base station Satellite gateway, A feeder link between a satellite and one of a satellite gateway or a base station, Is located in one of the service links between the satellite and a user equipment of a wireless communication system or another user equipment, or a specific point within a cell of the wireless communication system.

[0064] In an embodiment, when a geographical reference point is located in the feeder link, the control information further includes information describing the round-trip time or delay time of the feeder link between the reference point and one of a satellite gateway, a base station, or another reference point.

[0065] In an embodiment, the user equipment is further configured to time-synchronize communication with the base station using the round-trip time or delay time of the feeder link.

[0066] In an embodiment, when a geographical reference point is located in the service link, the control information further includes information describing the round-trip time or delay time of the feeder link between the satellite and one of a satellite gateway, a base station, or another reference point.

[0067] In an embodiment, the user equipment is further configured to time-synchronize communication with the base station using the round-trip time or delay time of the feeder link.

[0068] In an embodiment, the parameterized non-linear function describes the passage of the round-trip time or delay time between a first reference point and a second reference point, and the control information further describes [for example, a constant] part of the round-trip time or delay time between the base station and the satellite that is not described by the parameterized non-linear function [for example, when the first reference point is not located at the satellite, and / or when the second reference point is not located at the base station].

[0069] In an embodiment, the user equipment is further configured to time-synchronize communication with the base station using the part of the round-trip time or delay time that is not described by the parameterized non-linear function.

[0070] In an embodiment, the non - linear function is a power function or an exponential function or a polynomial function.

[0071] In an embodiment, the non - linear function is TIFF0007690601000005.tif758, TIFF0007690601000006.tif719 describes the determined round - trip time or delay time, TIFF0007690601000007.tif73, TIFF0007690601000008.tif73, and TIFF0007690601000009.tif73 describe the parameters signaled by the control information, TIFF0007690601000010.tif74 is the parameter TIFF0007690601000011.tif73, TIFF0007690601000012.tif73 and TIFF0007690601000013.tif73 describe the time [e.g., system frame number or slot number] at which they are signaled to the user equipment, TIFF0007690601000014.tif72 describes the specific [e.g., current] time at which the determined round - trip time or delay time is valid.

[0072] In an embodiment, the user equipment is configured to determine the timing advance for a specific [e.g., current] time [e.g., slot] based on a parameterized non - linear function [e.g., to determine a part of the timing advance (e.g., the common part of the timing advance) based on the parameterized non - linear function].

[0073] In an embodiment, the user equipment is configured to time - synchronize communication with the base station at a specific time based on the determined timing advance.

[0074] In the embodiment, the non-linear function is TIFF0007690601000015.tif7123, and TIFF0007690601000016.tif722 describes a common timing advance in units of TIFF0007690601000017.tif75, TIFF0007690601000018.tif716 is the third parameter of the parameter signaled in units of TIFF0007690601000019.tif75 and can be obtained via TIFF0007690601000020.tif73, TIFF0007690601000021.tif718 is the second parameter of the signaled parameter and can be obtained via TIFF0007690601000022.tif73, TIFF0007690601000023.tif717 is for each unit of TIFF0007690601000024.tif75 the first parameter of the parameter signaled in units of TIFF0007690601000025.tif75 and can be obtained via TIFF0007690601000026.tif73, TIFF0007690601000027.tif75 is the parameter TIFF0007690601000028.tif73, TIFF0007690601000029.tif73, and TIFF0007690601000030.tif73 describe the time [e.g., system frame number or slot number] at which they are signaled to the user equipment, and TIFF0007690601000031.tif722 describes the specific [e.g., current] time [e.g., system frame number or slot number] at which the determined timing advance is valid.

[0075] For example, the common timing advance is part of the timing advance and further incorporates the effects of common / feeder link delay.

[0076] In an embodiment, the non - linear function is TIFF0007690601000032.tif13122TIFF0007690601000033.tif7108, and TIFF0007690601000034.tif722 is described in units of TIFF0007690601000035.tif75 for the common timing advance, TIFF0007690601000036.tif716 is the third parameter of the parameter signaled in units of TIFF0007690601000037.tif75 and can be obtained via TIFF0007690601000038.tif73, TIFF0007690601000039.tif718 is the second parameter of the signaled parameter and can be obtained via TIFF0007690601000040.tif73, TIFF0007690601000041.tif717 is the first parameter of the signaled parameter and can be obtained via TIFF0007690601000042.tif73, TIFF0007690601000043.tif729 is for each unit of TIFF0007690601000044.tif75 the drift rate autonomously calculated by the UE in units of TIFF0007690601000045.tif75, TIFF0007690601000046.tif75 describes the reference time [e.g., system frame number or slot number] implicitly or explicitly indicated to the UE, TIFF0007690601000047.tif722 describes a specific [e.g., current] time [e.g., system frame number or slot number] at which the determined timing advance is valid.

[0077] For example, a common timing advance is part of the timing advance and further incorporates the effect of the common / feeder link delay.

[0078] In an embodiment, at least one parameter is for determining a timing advance signaled in units of TIFF0007690601000048.tif75, and the user equipment is configured to convert at least one parameter via TIFF0007690601000049.tif75 into at least one conversion parameter of an absolute value, and the user equipment is configured to use at least one conversion parameter for at least one other procedure.

[0079] In an embodiment, at least one other procedure is at least one from the calculation of a round-trip time or a delay time between the user equipment and a base station [e.g., in the case of "drx-HARQ-RTT-TimerDL", or in the case of compensation for "ra-ResponseWindow" and "msgB-ResponseWindow"].

[0080] In an embodiment, the control information signals an absolute parameter for parameterizing a non-linear function.

[0081] In an embodiment, the control information signals an index of an entry [e.g., a row] from a plurality of entries of a table, and each entry of the table stores at least one parameter associated with a corresponding satellite from a plurality of satellites of a communication system.

[0082] In an embodiment, the user equipment is configured to receive additional signaling information before handover to another satellite or switching to another feeder link in the case of handover to another satellite or switching to another feeder link, and the additional signaling information describes at least one additional parameter for parameterizing a non-linear function, and the additionally parameterized non-linear function describes the elapsed round-trip time or delay after handover to another satellite or switching to another feeder link.

[0083] In an embodiment, control information for signaling at least one parameter is transmitted via a system information block.

[0084] In an embodiment, the user equipment is configured to relay or retransmit signaling information for signaling at least one parameter to at least one other user equipment [e.g., unicast, multicast, groupcast or broadcast] of the wireless communication system via a sidelink.

[0085] In an embodiment, the user equipment is configured to communicate with at least two satellites, and the user equipment is configured to receive control information having at least one corresponding parameter for parameterizing a non-linear function for each of the at least two satellites.

[0086] In an embodiment, the user equipment is configured to communicate with a base station via a satellite using carrier aggregation.

[0087] In an embodiment, the user equipment is configured to communicate with a base station via a satellite as an auxiliary uplink.

[0088] A further embodiment provides a base station of a wireless communication system [e.g., 5G / new radio, NR], the base station being configured to communicate with a user equipment of the wireless communication system via a satellite of the wireless communication system, the base station being configured to transmit control information to the user equipment via the satellite, the control information signaling at least one parameter [e.g., one or more from parameters (a, b, c)] for parameterizing a non-linear function, and the parameterized non-linear function [e.g., the parameterized version of the non-linear function] describing the passage of round-trip time or latency time [e.g., variation] between the following, One from the satellite and a base station of the wireless communication system or a satellite gateway, The satellite and a geographical reference point of the wireless communication system, At a first reference point and a second reference point, the first reference point having a fixed relationship [e.g., distance] with respect to the satellite, and the second reference point having a fixed relationship [e.g., distance] with respect to one from the base station, the satellite gateway, or the user equipment, being the first reference point and the second reference point

[0089] [e.g., when the satellite is within the range of the user equipment and / or the satellite gateway] depending on the position of the satellite [e.g., with respect to the geographical reference point, the user equipment of the wireless communication system or the satellite gateway].

[0090] In an embodiment, the non-nonlinear function describes the passage of round-trip time or latency time between the satellite and one from the base station or the satellite gateway, and the round-trip time or latency time is the feeder link round-trip time or the feeder link latency time.

[0091] In an embodiment, the non-nonlinear function describes the passage of round-trip time or latency time between the satellite and the geographical reference point, and the round-trip time or latency time is the common round-trip time or the common latency time.

[0092] In an embodiment, the geographical reference point is, The base station, The satellite gateway, A feeder link between a satellite and one of a satellite gateway or a base station is located in one of the service links between the satellite and a user equipment of a wireless communication system or another user equipment, or a specific point within a cell of the wireless communication system.

[0093] In an embodiment, when the geographical reference point is located in the feeder link, the control information further includes information describing the round-trip time or delay time of the feeder link between the reference point and one of the satellite gateway or the base station.

[0094] In an embodiment, when the geographical reference point is located in the service link, the control information further includes information describing the round-trip time or delay time of the feeder link between the satellite and one of the satellite gateway or the base station.

[0095] In an embodiment, the parameterized non-linear function describes the elapsed round-trip time or delay time between a first reference point and a second reference point, and the control information further describes [for example, when the first reference point is not located at the satellite and / or the second reference point is not located at the base station] the [for example, constant] portion of the round-trip time or delay time between the base station and the satellite that is not described by the parameterized non-linear function.

[0096] In an embodiment, the non-linear function is a power function or an exponential function or a polynomial function.

[0097] In an embodiment, the non-linear function is TIFF0007690601000050.tif758, TIFF0007690601000051.tif719 describes the determined round-trip time or delay time, TIFF0007690601000052.tif73, TIFF0007690601000053.tif73, and TIFF0007690601000054.tif73 describe the parameters signaled by the control information. TIFF0007690601000055.tif74 describes the time [e.g., system frame number or slot number] at which TIFF0007690601000055.tif74, TIFF0007690601000056.tif73, TIFF0007690601000057.tif73 and TIFF0007690601000058.tif73 are signaled to the user equipment, TIFF0007690601000059.tif72 describes the specific [e.g., current] time at which the determined round-trip time or delay time is valid.

[0098] In an embodiment, the non-linear function is TIFF0007690601000060.tif7123, and TIFF0007690601000061.tif722 describes the common timing advance in units of TIFF0007690601000062.tif75, TIFF0007690601000063.tif716 is the third parameter of the parameter signaled in units of TIFF0007690601000064.tif75, which can be obtained via TIFF0007690601000065.tif73, TIFF0007690601000066.tif718 is the second parameter of the signaled parameter which can be obtained via TIFF0007690601000067.tif73, TIFF0007690601000068.tif717 is the first parameter of the parameter signaled in units of TIFF0007690601000070.tif75 per unit of TIFF0007690601000069.tif75, which can be obtained via TIFF0007690601000071.tif73, TIFF0007690601000072.tif75 describes the parameter TIFF0007690601000073.tif73, TIFF0007690601000074.tif73, and TIFF0007690601000075.tif73 to the user equipment signaling time [e.g., system frame number or slot number], TIFF0007690601000076.tif722 describes the specific [e.g., current] time [e.g., system frame number or slot number] at which the determined timing advance is valid.

[0099] For example, the common timing advance is part of the timing advance and further incorporates the effects of the common / feeder link delay.

[0100] In an embodiment, the non-linear function is TIFF0007690601000077.tif13122TIFF0007690601000078.tif7125, and TIFF0007690601000079.tif722 is TIFF0007690601000080.tif75 units to describe the common timing advance, TIFF0007690601000081.tif716 is TIFF0007690601000082.tif75 units of the third parameter of the signaling parameter TIFF0007690601000083.tif73 can be obtained through, TIFF0007690601000084.tif718 is the second parameter of the signaling parameter TIFF0007690601000085.tif73 can be obtained through, TIFF0007690601000086.tif717 is the first parameter of the signaling parameter Can be obtained via TIFF0007690601000087.tif73, TIFF0007690601000088.tif729 is, For each unit of TIFF0007690601000089.tif75, TIFF0007690601000090.tif75 is the drift rate autonomously calculated by the UE in units of 75, TIFF0007690601000091.tif75 describes the reference time [e.g., system frame number or slot number] indicated to the UE, TIFF0007690601000092.tif722 describes the specific [e.g., current] time [e.g., system frame number or slot number] at which the determined timing advance is valid.

[0101] For example, the common timing advance is part of the timing advance and further takes into account the impact of common / feeder link delay.

[0102] In an embodiment, the control information signals the absolute parameters for parameterizing the non - linear function.

[0103] In an embodiment, the control information signals the index [e.g., row] of an entry in a table [e.g., in a user equipment] where the corresponding parameter is stored.

[0104] In an embodiment, the control information signaling at least one parameter is transmitted via a system information block.

[0105] A further embodiment provides a method for operating a user equipment of a wireless communication system [e.g., 5G / new radio, NR]. The method comprises From a base station of the wireless communication system via a satellite of the wireless communication system, or From another user equipment of the wireless communication system via a sidelink, including the step of receiving control information, the control information signaling at least one parameter [e.g., one or more from parameters (a, b, c)] for parameterizing a non-linear function, and the parameterized non-linear function [e.g., the parameterized version of the non-linear function] describing the passage [e.g., variation] of the round-trip time or latency time between the following, from one of a satellite and a base station or satellite gateway of a wireless communication system, a geographical reference point of the satellite and the wireless communication system, a first reference point and a second reference point, the first reference point having a fixed relationship [e.g., distance] with respect to the satellite, and the second reference point having a fixed relationship [e.g., distance] with respect to one from a base station, a satellite gateway, or a user equipment,

[0106] depending on the position of the satellite [e.g., the user equipment or satellite gateway of the wireless communication system with respect to the geographical reference point] [e.g., when the satellite is within the range of the user equipment and / or satellite gateway].

[0107] A further embodiment provides a method for operating a base station [e.g., gNB] of a wireless communication system [e.g., 5G / new radio, NR]. The method includes the step of transmitting control information to a user equipment of the wireless communication system via a satellite of the wireless communication system, the control information signaling at least one parameter [e.g., one or more from parameters (a, b, c)] for parameterizing a non-linear function, and the parameterized non-linear function [e.g., the parameterized version of the non-linear function] describing the passage [e.g., variation] of the round-trip time or latency time between the following, from one of a satellite and a base station or satellite gateway of a wireless communication system, a geographical reference point of the satellite and the wireless communication system, A first reference point and a second reference point, wherein the first reference point has a fixed relationship [e.g., distance] with respect to the satellite, and the second reference point has a fixed relationship [e.g., distance] with respect to one of the base station, satellite gateway, or user equipment.

[0108] [For example, when the satellite is within the range of the user equipment and / or satellite gateway] It depends on the position of the satellite [e.g., with respect to a geographical reference point, the user equipment or satellite gateway of the wireless communication system].

[0109] Subsequently, embodiments of the present invention will be described in more detail.

[0110] As already described above, the end-to-end UE-gNB can be divided into two parts: UE-specific delay and UE-common delay. To enable understanding of the details of the common delay signaling, the UE-common delay can be divided into its components. Further, in the following, the terms RTT and delay are used interchangeably. In particular, considering FIG. 6, the UE-common delay / RTT can be written as follows. TIFF0007690601000093.tif7159, Here, · TIFF0007690601000094.tif724: Incorporate the RTT of the gNB to the gateway. Due to the fixed positions of both the gNB and the gateway, TIFF0007690601000095.tif724 is a constant.

[0111] · TIFF0007690601000096.tif719: Consider the estimation error of the UE-specific delay / RTT. The value of this term depends on the accuracy of the GNSS unit and can be considered constant.

[0112] · TIFF0007690601000097.tif723: Take into account the delay / RTT of the gateway to the satellite. Due to the movement of the satellite, TIFF0007690601000098.tif723 is a time-varying term. However, since the motion of the satellite is quasi-deterministic, i.e., the predicted satellite orbital motion + the minor random box motion of the satellite, TIFF0007690601000099.tif723 itself can be split into two terms. A deterministic and time-varying term + a constant term that takes into account the estimation error of the RTT of the gateway to the satellite due to the box movement of the satellite.

[0113] Considering the above description, TIFF0007690601000100.tif728 can be well approximated through the right side of the above equation, i.e., TIFF0007690601000101.tif779, TIFF0007690601000102.tif717 incorporates the effects of all constant terms, TIFF0007690601000103.tif723 is the only time-varying and deterministic term.

[0114] Before explaining the details of the signaling, it is worth mentioning how TIFF0007690601000104.tif723 can be evaluated. In particular, TIFF0007690601000105.tif723 is a function of the satellite altitude ( TIFF0007690601000106.tif73), the minimum elevation angle ( TIFF0007690601000107.tif79), the maximum elevation angle ( TIFF0007690601000108.tif79), and the satellite orbit inclination ( TIFF0007690601000109.tif73). Figures 9 and 10 show TIFF0007690601000110.tif723 for different system parameters.

[0115] Specifically, in Figure 9, from the gateway to the satellite, RTT to TIFF0007690601000111.tif723 is plotted for different satellite altitudes. Thereby, the vertical axis illustrates the RTT in ms units and the horizontal axis illustrates the time in s units. Altitude By raising TIFF0007690601000112.tif73, it can be observed that the visibility window of the satellite at the gateway increases. Furthermore, altitude For all values of altitude the "U" - shaped characteristic of TIFF0007690601000114.tif723 is preserved.

[0116] In Figure 10, the RTT from the gateway to the satellite, RTT to TIFF0007690601000115.tif723 is plotted for different maximum elevation angles. Thereby, the vertical axis illustrates the RTT in ms units and the horizontal axis illustrates the time in s units. Similar to the previous analysis, the maximum elevation angle It can be observed that different values of TIFF0007690601000116.tif79 change the visibility window of the satellite. However, the characteristics of TIFF0007690601000117.tif723 remain constant. For TIFF0007690601000118.tif79 and further for different ranges of the value of TIFF0007690601000119.tif73 as well, the same observations have been made regarding the behavior of TIFF0007690601000120.tif723.

[0117] One important conclusion from the above simulation results is that TIFF0007690601000121.tif723 exhibits a "U" - shaped characteristic. This specific characteristic can be adopted to design a signaling mechanism with low signaling overhead.

[0118] Signaling mechanism In an embodiment, TIFF0007690601000122.tif723 can be approximated as follows. TIFF0007690601000123.tif7114, Here, TIFF0007690601000124.tif710 and TIFF0007690601000125.tif73 are some constant values that can be obtained offline given satellite orbit parameters and / or an orbit. Function TIFF0007690601000126.tif79 is any function that can best capture the characteristics of

[0119] ·Function An example of TIFF0007690601000128.tif79 can be TIFF0007690601000129.tif716. This implicitly indicates that TIFF0007690601000131.tif7111·Parameter TIFF0007690601000132.tif73, b, and c can be obtained after parameter estimation.

[0120] ·Parameter TIFF0007690601000133.tif74 can be implicitly obtained by the UE or can be explicitly signaled to the UE. For example, TIFF0007690601000134.tif74 can be obtained from the system frame number (SFN) and "timestamp" slot number in which TIFF0007690601000135.tif73, b, and c are signaled to the UE.

[0121] To evaluate the accuracy of the method proposed above, the same parameter set as in [4] is considered. In Fig. 11, the common delay (the RTT of the feeder link) is plotted as a function of time for the simulated RTT and the estimated RTT via a power function. Thereby, the vertical axis illustrates the RTT in ms units, and the horizontal axis illustrates the time in s units. The estimated parameters for this particular scenario are TIFF0007690601000136.tif778. It can be observed that the actual RTT curve can be well approximated by a power function with very high accuracy compared to the piecewise linear approximation method. Furthermore, since the estimated parameters are calculated once offline and can be used for a longer time without the need for updates, the signaling overhead is significantly reduced compared to the piecewise linear approximation.

[0122] Below, first, the details of the common delay signaling of the TA procedure will be described. Second, the details of the signaling related to the other procedures introduced above will be further described.

[0123] Timing Advance Procedure In the timing advance mechanism, the following formula can be adopted for calculating the autonomous TA for the NTN UE [8]. TIFF0007690601000137.tif13116, Here, · TIFF0007690601000138.tif749, · TIFF0007690601000139.tif78 and TIFF0007690601000140.tif719 are defined in the same way as Release 16. In particular, TIFF0007690601000141.tif719's value is applied when transmitting the PRACH preamble (before RRC connection), TIFF0007690601000142.tif78 is 0. After RRC connection, via the TA command TIFF0007690601000143.tif78 is calculated, · TIFF0007690601000144.tif728 is the UE self-estimated TA, · TIFF0007690601000145.tif722 is the network-controlled common TA and may include any timing offset considered necessary by the network.

[0124] In the above formula, TIFF0007690601000146.tif728 is a parameter called UE-specific delay / RTT in this specification. Furthermore, TIFF0007690601000147.tif722 is called UE common delay / RTT in this specification, TIFF0007690601000148.tif728, and is a parameter whose signaling is focused on. In the case of the TA procedure, TIFF0007690601000149.tif728 = TIFF0007690601000150.tif733, TIFF0007690601000151.tif722 is TIFF0007690601000152.tif75 units. Therefore, in an embodiment, TIFF0007690601000153.tif722 can be determined as one of the following two methods.

[0125] According to the first method, TIFF0007690601000154.tif722 can be determined as follows. TIFF0007690601000155.tif7123, Here, · TIFF0007690601000156.tif715 is TIFF0007690601000157.tif74 units, the estimated parameters TIFF0007690601000158.tif73 can be obtained through · TIFF0007690601000159.tif718 is the estimated parameter TIFF0007690601000160.tif73 can be obtained through · TIFF0007690601000161.tif716 is TIFF0007690601000162.tif75 per unit of TIFF0007690601000163.tif74 units, the estimated parameter TIFF0007690601000164.tif73 can be obtained through · TIFF0007690601000165.tif721 is the current uplink slot number, and · TIFF0007690601000166.tif75 is TIFF0007690601000167.tif715, TIFF0007690601000168.tif718, TIFF0007690601000169.tif722 is the "timestamp" slot number signaled to the UE.

[0126] According to the second method, TIFF0007690601000170.tif722 can be determined as follows. TIFF0007690601000171.tif13122, TIFF0007690601000172.tif7108 Here, · TIFF0007690601000173.tif715 is Estimated parameters in units of 74 for TIFF0007690601000174 Can be obtained via TIFF0007690601000175 with 73, · 718 for TIFF0007690601000176 are estimated parameters Can be obtained via TIFF0007690601000177 with 73, · 716 for TIFF0007690601000178 are estimated parameters Can be obtained via TIFF0007690601000179 with 73, · 729 for TIFF0007690601000180 is the (UE self - estimation) UE autonomous calculation drift rate per slot in units of 74, and for TIFF0007690601000181 with 74 units, · 721 for TIFF0007690601000182 is the current uplink slot number, · 75 for TIFF0007690601000183 is the reference slot number, e.g., the "timestamp" slot number implicitly or explicitly signaled to the UE.

[0127] In NTN, for Rel17, the UE must calculate the timing advance value and, correspondingly, the common delay before starting the RACH procedure, i.e., before transmitting the preamble (MSG1) via PRACH. By doing so, the UE acquires time synchronization in its corresponding UL transmission. As a result, the estimated parameters 710 for TIFF0007690601000184 and 73 (in the case of the TA procedure, for 715 for TIFF0007690601000186, TIFF0007690601000187.tif718, TIFF0007690601000188.tif716) must be signaled to the UE before the PRACH starts.

[0128] In an embodiment, the estimated parameter TIFF0007690601000189.tif710 and TIFF0007690601000190.tif73 (in the case of the TA procedure TIFF0007690601000191.tif715, TIFF0007690601000192.tif718, TIFF0007690601000193.tif716) can be broadcast via a system information block (SIB), e.g., SIB1 or any SIB dedicated to NTN.

[0129] Other procedures In the case of other procedures introduced at the beginning of this document, if the estimated parameter is first signaled (in TIFF0007690601000194.tif74 units) for the TA procedure, the UE can TIFF0007690601000195.tif74 to convert the estimated parameter to an absolute value. Then, the UE can adopt the absolute value of the estimated parameter for the calculation of the UE common delay and, as a result, the end-to-end UE-gNB delay required in other procedures.

[0130] Other signaling modes Below, other related aspects of common delay signaling will be described.

[0131] According to a first aspect, the signaling method described above is also effective for a plurality of UEs within a cell. Furthermore, the signaling method described above is also effective for one UE that communicates with a plurality of satellites and / or communicates via carrier aggregation and / or communicates via a supplementary uplink.

[0132] Accordingly, in the case of neighboring UEs, signaling may also be delivered using a sidelink as a direct communication link between the UEs.

[0133] Also, in the case of a sidelink, any of (1) broadcast (delivering relevant information to all UEs in the vicinity), (2) groupcast / multicast (delivering using a configured or naturally occurring group of UEs, where one UE can function as a group head responsible for delivering satellite-specific information), or (3) unicast (an individual link to one neighboring UE) may be applicable.

[0134] Furthermore, in the case of Uu, multicast (a group of UEs using the satellite for communication) may also be used to deliver satellite-specific information (e.g., drift correction).

[0135] According to a second aspect, since satellite orbital motion is predictable, the geographical position is fixed, and for UEs within a cell served by a plurality of satellites, the satellites of TIFF0007690601000196.tif72, TIFF0007690601000197.tif733, where TIFF0007690601000198.tif74 is the total number of satellites, and the estimated parameters TIFF0007690601000199.tif713 and TIFF0007690601000200.tif74 can be stored as the second row of a lookup table.

[0136] Thereby, the lookup table can be configured for the UE via RRC signaling.

[0137] According to the serving satellite, at a certain point in time, the gNB can signal the corresponding index value of the corresponding row in the lookup table.

[0138] According to the third aspect, all of the above descriptions are also valid when the absolute value of the estimated parameter is signaled to the UE instead of index signaling.

[0139] According to the sixth aspect, for the handover procedure, the estimated parameters of the new satellite to which the UE is attempting to hand over TIFF0007690601000202.tif723 and TIFF0007690601000203.tif79 are signaled via the current serving satellite before the handover procedure, or TIFF0007690601000204.tif723 and if TIFF0007690601000205.tif79 is stored in the lookup table, TIFF0007690601000206.tif723 and the corresponding index of TIFF0007690601000207.tif79 is sent to the UE.

[0140] According to the seventh aspect, in the case of feeder link switching, the estimated parameters associated with the common delay experienced via the new / switched gateway in the feeder link TIFF0007690601000208.tif730 and TIFF0007690601000209.tif713, or its corresponding index in the lookup table, are signaled to the UE before the feeder link switching occurs.

[0141] According to the eighth aspect, all the methods described above are also effective when the UE is composed of multiple lookup tables, each lookup table is configured for different procedures, and each row of the lookup table corresponds to a potential serving satellite.

[0142] Thereby, a signaling mechanism for activating / deactivating one table from a set of RRC configuration lookup tables by DCI information.

[0143] According to the ninth aspect, the periodicity / frequency at which reports are exchanged: This may depend on any possible drift of the satellite or the movement speed and / or direction of the UE.

[0144] Further embodiments The embodiments described herein may be implemented or used for some procedures (see below) in RAN1 and RAN2 that require enhancement of NTN according to the round-trip time (RTT) of the UE and gNB.

[0145] As described above, the UE-gNB RTT in NTN can be divided into two parts, namely, the common RTT (or common delay) and the UE-specific RTT (or UE-specific delay).

[0146] Thereby, the UE-specific delay is the delay of the UE to the satellite that can be obtained, for example, via the UE GNSS unit and satellite ephemeris.

[0147] The common delay is common to all UEs. The common delay incorporates the delay of the gNB-gateway-satellite (feeder link).

[0148] The embodiments described herein can be implemented or used for procedures affected by the UE-gNB RTT, such as one or more of the following.

[0149] ·RAN2: 4-step RACH, 2-step RACH procedure, · RAN2: drx-HARQ-RTT timer, · RAN1: Timing Advance procedure, · RAN1: Feeder link switching procedure.

[0150] As described above, the common delay is under the control of the network and needs to be signaled to all UEs within the cell. Due to the movement of the satellite, the common delay changes over time and frequent signaling from the network side to the UE is required to update the value of the common delay. The embodiment provides a signaling mechanism for the common delay with low signaling overhead.

[0151] According to the embodiment, the common delay (and feeder link RTT) having the characteristics of a "U" shape characteristic is approximated by a power function, i.e., at b + c (see Figure 11). The embodiment achieves a very accurate approximation of the RTT function. Since only three parameters (a, b, c) need to be signaled, the signaling overhead can be significantly reduced.

[0152] The various elements and features of the present invention may be implemented in hardware using analog and / or digital circuits, in software, through the execution of instructions by one or more general-purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of the present invention may be implemented in the environment of a computer system or another processing system. FIG. 12 shows an example of a computer system 500. Units or modules, as well as the steps of the methods executed by these units, can be executed on one or more computer systems 500. The computer system 500 includes one or more processors 502, such as a dedicated or general-purpose digital signal processor. The processor 502 is connected to a communication infrastructure 504, such as a bus or a network. The computer system 500 further includes a main memory 506, such as random access memory (RAM), and a secondary memory 508, such as a hard disk drive and / or a removable storage drive. The secondary memory 508 may enable computer programs or other instructions to be loaded into the computer system 500. The computer system 500 may further include a communication interface 510 that enables software and data to be transferred between the computer system 500 and external devices. The communication may be in the form of electronic, electromagnetic, optical, or other signals that can be processed by the communication interface. The communication may use wires or cables, optical fibers, telephone lines, cellular phone links, RF links, and other communication channels 512.

[0153] The terms "computer program medium" and "computer readable medium" are generally used to refer to tangible storage media such as removable storage units or hard disks installed in hard disk drives. These computer program products are means for providing software to a computer system 500. A computer program, also called computer control logic, is stored in main memory 506 and / or secondary memory 508. A computer program can also be received via communication interface 510. When executed, the computer program enables the computer system 500 to implement the present invention. In particular, when executed, the computer program enables the processor 502 to implement a process of the present invention such as any of the methods described herein. Thus, such a computer program can represent a controller of the computer system 500. When the present disclosure is implemented using software, the software is stored in a computer program product and may be loaded into the computer system 500 using an interface such as a removable storage drive, communication interface 510.

[0154] Implementation in hardware or software can be carried out using digital storage media, such as cloud storage, floppy disks, DVDs, Blu-rays, CDs, ROMs, PROMs, EPROMs, EEPROMs, flash memories, which cooperate (or can cooperate) with a programmable computer system in which electronically readable control signals are stored and in which respective methods are executed. Thus, digital storage media can be computer readable.

[0155] Some embodiments according to the present invention include a data carrier having electronically readable control signals that can cooperate with a programmable computer system so that one of the methods described herein is executed.

[0156] In general, embodiments of the present invention may be implemented as a computer program product having program code, which, when the computer program product is executed on a computer, operates to perform one of the methods. The program code may be stored, for example, in a machine-readable carrier.

[0157] Other embodiments include a computer program stored in a machine-readable carrier and for performing one of the methods described herein. In other words, one embodiment of the method of the present invention is thus a computer program having program code for performing one of the methods described herein when the computer program is executed on a computer.

[0158] Accordingly, a further embodiment of the method of the present invention includes a computer program for performing one of the methods described herein and a data carrier (or digital storage medium, or computer-readable medium) on which it is recorded. Accordingly, a further embodiment of the method of the present invention is a sequence of data streams or signals representing a computer program for performing one of the methods described herein. The sequence of data streams or signals may be configured to be transferred via a data communication connection such as the Internet, for example. A further embodiment includes processing means, such as a computer or a programmable logic device, configured or adapted to perform one of the methods described herein. A further embodiment includes a computer on which is installed a computer program for performing one of the methods described herein.

[0159] In some embodiments, a programmable logic device (e.g., a field programmable gate array) can be used to perform some or all of the functions of the methods described herein. In some embodiments, the field programmable gate array can cooperate with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware device.

[0160] It should be understood by those skilled in the art that the above-described embodiments merely illustrate the principles of the present invention. Changes and modifications to the configurations and details described herein will be apparent to those skilled in the art. Therefore, it is intended to be limited only by the claims that follow immediately and not by the specific details presented in the description of the embodiments herein for purposes of illustration and explanation.

[0161] References [1] 3GPP TR 38.811, “Study on New Radio (NR) to support non terrestrial networks (Release 15),” 3rd Generation Partnership Project; Technical Specification Group Radio Access Network, Version 15.1.0, June 2019.

[0162] [2] 3GPP TR 38.821 v16.0.0 (2019-12): 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Solutions for NR to support non-terrestrial networks (NTN) (Release 16).

[0163] [3] US 2020 / 0196263 A1

[0164] [4] R1-2100927, “On UL time and frequency synchronization enhancements for NTN”, Ericsson, Jan. 2021.

[0165] [5] R2-2010702, “Report from Break-out session on R16 eMIMO, CLI, PRN, RACS and R17 NTN and REDCAP”, Nov. 2020.

[0166] [6] R2-2101952, “Report from Break-out session on R16 eMIMO, CLI, PRN, RACS and R17 NTN and REDCAP”, Jan. 2021.

[0167] [7] 3GPP TSG RAN WG1 Meeting #104-e, “RAN1 Chairman’s Notes”, Jan. 2021.

[0168] [8] 3GPP TSG RAN WG1 Meeting #104-e, “RAN1 Chairman’s Notes 8.4 v005”, Jan. 2021.

[0169] Abbreviations 3GPP 3rd Generation Partnership Project AIM Support Information Message AL Alert Limit AMF Access and Mobility Management Function ARAIM Advanced Receiver Autonomous Integrity Monitoring BS Base Station BWP Bandwidth Part CA Carrier Aggregation CC Component Carrier CBG Code Block Group CBR Channel Busy Ratio D2D Device-to-Device DAI Downlink Allocation Index DCI Downlink Control Information DL Downlink FFT Fast Fourier Transform GMLC Gateway Mobile Location Center gNB evolved Node B (NR base station) / Next Generation Node B base station GNSS Global Navigation Satellite System GTW Gateway HAL Horizontal Alert Limit HARQ Hybrid Automatic Repeat reQuest IoT Internet of Things LCS Location Service LEO Low Earth Orbit LMF Location Management Function LPP LTE Positioning Protocol LTE Long Term Evolution MAC Media Access Control MCR Minimum Communication Range MCS Modulation and Coding Scheme MIB Master Information Block MO-LR Mobile Originating Location Request MT-LR Mobile Terminating Location Request NB Node B NI-LR Network Initiated Location Request NR new radio NRPPa NR Positioning Protocol Annex NTN Non-Terrestrial Network NW Network OFDM Orthogonal Frequency Division Multiplexing OFDMA Orthogonal Frequency Division Multiple Access PBCH Physical Broadcast Channel PC5 Interface for using sidelink channels for D2D communication PDCCH Physical Downlink Control Channel PDSCH Physical Downlink Shared Channel PL Protection Level PLMN Public Land Mobile Network PPP Point-to-Point Protocol PPP Precise Point Positioning PRACH Physical Random Access Channel PRB Physical Resource Block PRS Public Regulated Service (Galileo) PSCCH Physical Sidelink Control Channel PSSCH Physical Sidelink Shared Channel PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel PVT Position and / or Velocity and / or Time PVT Position, Velocity and Time RAIM Receiver Autonomous Integrity Monitoring RAN Radio Access Network RAT Radio Access Technology RB Resource Block RNTI Radio Network Temporary Identifier RP Reference Point RRC Radio Resource Control RS Reference Symbol / Signal RTK Real-Time Kinematics RTT Round-Trip Time Sat Satellite SBAS Space-Based Augmentation System SBI Service-Based Interface SCI Sidelink Control Information SI System Information SIB Sidelink Information Block SL Sidelink SSR State Space Representation sTTI Short Transmission Time Interval TA Timing Advance TDD Time Division Duplex TDOA Time Difference of Arrival TIR Target Integrity Risk TRP Transmit and Receive Point TTA time-to-alert TTI Transmission Time Interval UAV Unmanned Aerial Vehicle UCI Uplink Control Information UE User Equipment UL Uplink UMTS Universal Mobile Telecommunications System V2x Vehicle-to-Everything V2V Vehicle-to-Vehicle V2I Vehicle-to-Infrastructure V2P Vehicle-to-Pedestrian V2N Vehicle-to-Network VLEO Very Low Earth Orbit P-UE Pedestrian UE V-UE Vulnerable UE

Claims

1. A user equipment of a wireless communication system, wherein the user equipment is configured to communicate with a base station of the wireless communication system via a satellite of the wireless communication system, wherein the user equipment is configured to receive control information from the base station via the satellite or from another user equipment of the wireless communication system via a sidelink, the control information signaling parameters for parameterizing a non-linear function, and the user equipment is configured to parameterize the non-linear function using the parameters notified by the control information, and the parameterized non-linear function is - between the satellite and one of the base station or satellite gateway of the wireless communication system, or - between the satellite and a geographical reference point of the wireless communication system, or - between a first reference point and a second reference point, the first reference point having a fixed relationship with respect to the satellite, and the second reference point having a fixed relationship with respect to one of the base station, satellite gateway, or user equipment, describing the passage of a delay time according to the position of the satellite, wherein the user equipment is configured to perform time synchronization of signal transmission and / or reception for communication with the base station at a specific time using the parameterized non-linear function, To obtain the determined delay time, the user equipment is configured to determine the delay time at the specific time using the parameterized non-linear function, and the user equipment is configured to perform time synchronization of signal transmission and / or reception for communication with the base station at the specific time based on the determined delay time. A user equipment.

2. The non-linear function describes the passage of the delay time between the satellite and one of the base station or satellite gateway, the delay time is a feeder link delay time which is a specific delay time describing the passage, or the non-linear function describes the passage of the delay time between the satellite and the geographical reference point, and the delay time is a common delay time, or The parameterized non-linear function describes the passage of the delay time between the first reference point and the second reference point, and the control information further describes a portion of the delay time between the base station and the satellite that is not described by the parameterized non-linear function. The user equipment according to claim 1.

3. The user equipment is further configured to synchronize the transmission and / or reception time of signals for communication with the base station by using the portion of the delay time that is not described by the parameterized non-linear function. The user equipment according to claim 2.

4. The non-linear function is a power function, an exponential function, or a polynomial function. The user equipment according to any one of claims 1 to 3.

5. The non-linear function is where describes the determined delay time, 、 and describes the parameters signaled by the control information, where the parameter 、 and describe the time at which the parameters are signaled to the user equipment, and describes the specific time at which the determined delay time is valid. The user equipment according to any one of claims 1 to 4.

6. The control information signals absolute parameters for parameterizing the non-linear function, or the control information that signals the parameters is transmitted via a system information block. The user equipment according to any one of claims 1 to 5.

7. The user equipment is configured to receive additional signaling information before the handover to another satellite or the switch to another feeder link in the case of a handover to another satellite or a switch to another feeder link, the additional signaling information describes at least one additional parameter for parameterizing the non-linear function, and the additional parameterized non-linear function describes the passage of the delay after the handover to the other satellite or the switch to the other feeder link, or The user equipment is configured to relay or retransmit the control information that signals the parameters to at least one other user equipment of the wireless communication system via the sidelink, or The user equipment is configured to communicate with at least two satellites. The user equipment is configured to receive control information having corresponding parameters for parameterizing the non-linear function for each of the at least two satellites, or the user equipment is configured to communicate with the base station via the satellite using carrier aggregation, or the user equipment is configured to communicate with the base station via the satellite as an auxiliary uplink, The user equipment according to any one of claims 1 to 6.

8. A base station of a wireless communication system, wherein the base station is configured to communicate with a user equipment of the wireless communication system via a satellite of the wireless communication system, the base station is configured to transmit control information to the user equipment via the satellite, the control information signaling parameters for parameterizing a non-linear function, and the user equipment is configured to parameterize the non-linear function using the parameters notified by the control information, and the parameterized non-linear function is - between the satellite and one of the base station or satellite gateway of the wireless communication system, or - between the satellite and a geographical reference point of the wireless communication system, or - between a first reference point and a second reference point, the first reference point having a fixed relationship with respect to the satellite, and the second reference point having a fixed relationship with respect to one of the base station, satellite gateway, or user equipment, between the first reference point and the second reference point, A base station that describes the passage of a delay time according to the position of the satellite.

9. The non-linear function describes the passage of the delay time between the satellite and one of the base station or satellite gateway, the delay time is a feeder link delay time that is a specific delay time describing the passage, or the non-linear function describes the passage of the delay time between the satellite and the geographical reference point, and the delay time is a common delay time, or the parameterized non-linear function describes the passage of the delay time between the first reference point and the second reference point, and the control information further describes a portion of the delay time between the base station and the satellite that is not described by the parameterized non-linear function, The base station according to claim 8.

10. The non-linear function is a power function, an exponential function, or a polynomial function. The base station according to any one of claims 8 to 9.

11. The non-linear function is where describes a determined delay time, 、 and describes the parameter signaled by the control information, where the parameter 、 and describe the time when the parameter is signaled to the user equipment, describes a specific time when the determined delay time is valid. The base station according to any one of claims 8 to 10.

12. The control information signals an absolute parameter for parameterizing the non-linear function, or the control information signals an index of an entry in a table in which the corresponding parameter is stored, or the control information signaling the parameter is transmitted via a system information block. The base station according to any one of claims 8 to 11.

13. A method for operating a user equipment of a wireless communication system, the method comprising: receiving control information from a base station of the wireless communication system via a satellite of the wireless communication system or from another user equipment of the wireless communication system via a sidelink, wherein the control information signals a parameter for parameterizing a non-linear function, parameterizes the non-linear function using the parameter notified by the control information, and the parameterized non-linear function is - between the satellite and one of the base station or satellite gateway of the wireless communication system, or - between the satellite and a geographical reference point of the wireless communication system, or - between a first reference point and a second reference point, wherein the first reference point has a fixed relationship with respect to the satellite, and the second reference point has a fixed relationship with respect to one of the base station, satellite gateway, or user equipment, describes the elapse of a delay time according to the position of the satellite, and synchronizes the transmission and / or reception time of a signal for communication with the base station at a specific time using the parameterized non-linear function. ​ A method for determining a determined delay time, including determining, using the parameterized non-linear function, a delay time at the specific time, and performing time synchronization of signal transmission and / or reception for the communication with the base station at the specific time based on the determined delay time.

14. A method for operating a base station of a wireless communication system, the method including: transmitting control information to a user equipment of the wireless communication system via a satellite of the wireless communication system, the control information signaling parameters for parameterizing a non-linear function, parameterizing the non-linear function using the parameters notified by the control information, and the parameterized non-linear function - between the satellite and one of the base station or satellite gateway of the wireless communication system, or - between the satellite and a geographical reference point of the wireless communication system, or - between a first reference point and a second reference point, the first reference point having a fixed relationship with respect to the satellite, and the second reference point having a fixed relationship with respect to one of the base station, satellite gateway, or user equipment, describing the passage of a delay time according to the position of the satellite. Method.

15. A computer program for executing the method according to any one of claims 13 to 14.

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