Satellite switching method and device in non-ground network

Abstract

The invention provides a satellite switching method executed by user equipment (UE). The method obtains a first configuration associated with a first satellite from a cell. The first configuration includes a timestamp and time information. The method performs downlink (DL) synchronization with the first satellite starting from a time indicated by the timestamp based on the time information. The method then reacquires a second configuration associated with the first satellite from the first satellite, and calculates a common timing advance and a UE-specific timing advance based on the reacquired second configuration associated with the first satellite.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Application Serial No. 63 / 530,534, filed on August 3, 2023, entitled “METHOD AND APPARATUS FOR SERVERING SATELLITE SWITCHING INNON-TERRESTRIAL NETWORK”. The contents of that application are hereby incorporated by reference in their entirety into this application. Technical Field

[0002] The present invention relates generally to wireless communications and, more particularly, to methods and apparatus for satellite handoff in non-terrestrial networks. Background Art

[0003] Various efforts have been made to improve different aspects of wireless communication in cellular wireless communication systems, such as 5G New Radio (NR), by improving data rates, latency, reliability, and mobility. The 5G NR system is designed to provide flexibility and configurability to optimize network services and types to accommodate a variety of use cases, such as enhanced Mobile Broadband (eMBB), massive Machine-Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC). However, as the demand for radio access continues to increase, there is a need for further improvements in the field. Summary of the invention

[0004] The present application relates to a satellite switching method and device in a non-terrestrial network.

[0005] According to a first aspect of the present application, a satellite switching method performed by a user equipment (UE) is provided. The method includes acquiring a first configuration related to a first satellite from a cell, the first configuration including a timestamp and time information; performing downlink DL synchronization with the first satellite starting from the time indicated by the timestamp based on the time information; reacquiring a second configuration related to the first satellite from the first satellite; and calculating a common timing advance and a UE-specific timing advance based on the reacquired second configuration related to the first satellite.

[0006] In some implementations of the first aspect of the present application, the first configuration related to the first satellite also includes timer information, and the method also includes: starting the timer based on the timer information at the time indicated by the timestamp.

[0007] In some implementations of the first aspect of the present application, the timer includes a radio resource control RRC timer.

[0008] In some implementations of the first aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes acquiring the first configuration related to the first satellite from the second satellite, and the timer is configured to control the validity of uplink synchronization during the connection with the second satellite.

[0009] In some implementations of the first aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes: acquiring the first configuration related to the first satellite from the second satellite, wherein both the first satellite and the second satellite are associated with the cell.

[0010] In some implementations of the first aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes receiving system information broadcast by the cell, and the system information includes the first configuration related to the first satellite.

[0011] In some implementations of the first aspect of the present application, the system information includes at least one of system information block type 1 SIB1 and system information block type 19 SIB19.

[0012] In some implementations of the first aspect of the present application, performing DL synchronization with the first satellite includes: receiving a synchronization signal block SSB of the first satellite based on time information.

[0013] In some implementations of the first aspect of the present application, the time information is associated with the SSB and is in units of subframes.

[0014] In some implementations of the first aspect of the present application, reacquiring the second configuration related to the first satellite from the first satellite includes: reacquiring the second configuration related to the first satellite from the first satellite after performing DL synchronization with the first satellite.

[0015] According to a second aspect of the present application, a user equipment (UE) is provided. The UE includes one or more non-transitory computer-readable media storing one or more computer-executable instructions; and at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor being configured to execute one or more computer-executable instructions to enable the UE to: acquire a first configuration related to a first satellite from a cell, the first configuration including a timestamp and time information; perform downlink DL synchronization with the first satellite starting from the time indicated by the timestamp based on the time information; reacquire a second configuration related to the first satellite from the first satellite; and calculate a common timing advance and a UE-specific timing advance based on the reacquired second configuration related to the first satellite.

[0016] In some implementations of the second aspect of the present application, the first configuration related to the first satellite also includes timer information, and when executed by at least one processor, the one or more computer-executable instructions further cause the UE to: start a timer based on the timer information at a time indicated by the timestamp.

[0017] In some implementations of the second aspect of the present application, the timer includes a radio resource control RRC timer.

[0018] In some implementations of the second aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes acquiring the first configuration related to the first satellite from the second satellite, and the timer is configured to control the validity of uplink synchronization during the connection with the second satellite.

[0019] In some implementations of the second aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes: acquiring the first configuration related to the first satellite from the second satellite, wherein both the first satellite and the second satellite are associated with the cell.

[0020] In some implementations of the second aspect of the present application, acquiring the first configuration related to the first satellite from the cell includes receiving system information broadcast by the cell, and the system information includes the first configuration related to the first satellite.

[0021] In some implementations of the second aspect of the present application, the system information includes at least one of system information block type 1 SIB1 and system information block type 19 SIB19.

[0022] In some implementations of the second aspect of the present application, performing DL synchronization with the first satellite includes: receiving a synchronization signal block SSB of the first satellite based on time information.

[0023] In some implementations of the second aspect of the present application, the time information is associated with the SSB and is in units of subframes.

[0024] In some implementations of the second aspect of the present application, reacquiring the second configuration related to the first satellite from the first satellite includes: reacquiring the second configuration related to the first satellite from the first satellite after performing DL synchronization with the first satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various aspects of the present exemplary disclosure are best understood from the following detailed description when read in conjunction with the accompanying drawings. For clarity of discussion, various features are not drawn to scale and the sizes of the various features may be arbitrarily increased or reduced.

[0026] Figure 1Shown is a diagram of a non-terrestrial network (NTN) of an exemplary embodiment of the present application.

[0027] Figure 2 Shown is a diagram of NTN for transparent NTN payload according to an exemplary embodiment of the present application.

[0028] Figure 3 Shown is a diagram of soft satellite switching in a quasi-geo-fixed cell scenario according to an exemplary embodiment of the present application.

[0029] Figure 4 Shown is a diagram of hard satellite handover in a quasi-geo-fixed cell scenario according to an exemplary embodiment of the present application.

[0030] Figure 5 Shown is a signaling diagram of a signaling-based network-controlled satellite switching process according to an exemplary embodiment of the present application.

[0031] Figure 6 Shown is a signaling diagram of a time-based network-controlled satellite switching process according to an exemplary embodiment of the present application.

[0032] Figure 7 Shown is a signaling diagram of a satellite switching procedure initiated by a UE according to an exemplary embodiment of the present application.

[0033] Figure 8 Shown is a flow chart of a method / process for satellite handover according to an exemplary embodiment of the present application.

[0034] Fig. 9 Shown is a block diagram of a node for wireless communication according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0035] Some abbreviations described in this application are defined as follows. Unless otherwise specified, the terms in this application have the following meanings. Full name abbreviation 3rd Generation Partnership Project (3GPP) Acknowledgement (ACK) Bandwidth Aggregation (BA) Beam Failure Recovery (BFR) Base Station (BS) Band Width Part (BWP) Carrier Aggregation (CA) Control Element (CE) Control Resource Set (CORESET) Channel Occupancy Time (COT) Cell Radio Network Temporary Identifier (C-RNTI) Channel State Information (CSI) Dual Connectivity (DC) Downlink Control Information (DCI) DCI with CRC scrambled by PS-RNTI (DCP) Downlink (DL) Discontinuous Reception (DRX) Global Navigation Satellite System (GNSS) Global Synchronization Channel Number (GSCN) Geosynchronous Orbit (GSO) Gateway (GateWay, GW) Hybrid Automatic Repeat request (HARQ) Hybrid automatic repeat request acknowledgement (HARQ-ACK) Information Element (IE) Layer 1 (L1) Layer 2 (L2) Layer 3 (L3) Listen Before Talk (LBT) Link Radio (LRR) Media Access Control (MAC) Master Cell Group (MCG) Multi-Input Multi-Output (MIMO) Message 1 (Msg1) Message A (Message A, MsgA) Message B (MsgB) Non-Acknowledgement (NACK) Non-GeoSynchronous Orbit (NGSO) Non-Terrestrial Network (NTN) Network (NW) Primary Cell (PCell) Physical Downlink Control Channel (PDCCH) Physical Downlink Shared Channel (PDSCH) Packet Data Convergence Protocol (PDCP) Physical layer (Physical, PHY) Path-Loss Reference Signal (PL-RS) Physical Random Access Channel (PRACH) Power Saving (PS) Physical Uplink Control Channel (PUCCH)Physical Uplink Shared Channel (PUSCH)Random Access (RA) Random Access Response (RAR) Release (Rel) Radio Link Failure (RLF) Radio Network Temporary Identifier (RNTI) Reference Point (RP) Radio Resource Control (RRC) Radio Resource Management (RRM) Reference Signal Received Power (RSRP) Round Trip Time (RTT) Satellite (SAT) Secondary Cell (SCell) Secondary Cell Group (SCG) Subcarrier Spacing (SCS) System Frame Number (SFN) System Information (SI) System Information Block (SIB) SSB Measurement Timing Configuration (SMTC) Scheduling Request (SR) Synchronization Signal (SS) Synchronization Signal Block (SSB) Timing Advance (TA) Transport Network Layer (TNL) Uplink Control Information (UCI) User Equipment (UE) Uplink (UL)

[0036] The following contains specific information related to the implementation of the present application. The drawings and the detailed description attached thereto are only for the embodiments. However, the present application is not limited to these embodiments. Other variations and embodiments of the present application will be apparent to those skilled in the art. Unless otherwise specified, the same or corresponding parts in the drawings may be represented by the same or corresponding figure numerals. In addition, the drawings and illustrations in the present application are generally not drawn to scale and are not intended to correspond to actual relative sizes.

[0037] For the purpose of consistency and ease of understanding, similar features may be labeled with the same numbers in the drawings (although not so labeled in some examples). However, the features in different embodiments may differ in other aspects and should not be narrowly limited to what is shown in the drawings.

[0038] The phrase "in some embodiments" is used in the specification to refer to one or more identical or different embodiments. The term "coupled" is defined as connected, whether directly or indirectly through intermediate components, and is not necessarily limited to physical connections. The term "comprising" means "including but not necessarily limited to" and represents an open inclusion or member in the disclosed combinations, groups, series, and equivalents. The expression "at least one of A, B, and C" or "at least one of the following: A, B, and C" means "only A, or only B, or only C, or any combination of A, B, and C".

[0039] In addition, for the purpose of explanation and non-limitation, specific details such as functional entities, technologies, protocols, standards, etc. are set forth to provide an understanding of the described technology. In other examples, detailed descriptions of well-known methods, technologies, systems, architectures, etc. are omitted to avoid making the present application unclear with unnecessary details.

[0040] Those skilled in the art will immediately recognize that any NW function or algorithm of the present application can be implemented by hardware, software or a combination of software and hardware. The disclosed functions may correspond to modules, which may be software, hardware, firmware or any combination thereof. Software implementations may include computer executable instructions stored on a computer-readable medium such as a memory or other type of storage device, such as a memory or other type of storage device. One or more microprocessors or general-purpose computers with communication processing capabilities may be programmed using corresponding executable instructions and perform the described NW functions or algorithms. A microprocessor or general-purpose computer may be formed by a dedicated integrated circuit (Applications Specific Integrated Circuitry, ASIC), a programmable logic array and / or using one or more digital signal processors (Digital Signal Processor, DSP). Although several exemplary embodiments described in the present application are for software installed and executed on computer hardware, alternative exemplary embodiments implemented as a combination of firmware, hardware or hardware and software are also within the scope of the present application.

[0041] Computer readable media include, but are not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), Electronically Erasable Programmable Read-Only Memory (EEPROM), flash memory, Compact Disc Read-Only Memory (CD-ROM), cassettes, magnetic tapes, disk storage, or any other equivalent media that can store computer readable instructions.

[0042] A radio communication network architecture such as a Long Term Evolution (LTE) system, an LTE Advanced (LTE-A) system, an LTE Advanced Pro system, or a 5G NR Radio Access Network (RAN)) may typically include at least one base station, at least one UE, and one or more optional network components that provide connectivity in the network. The UE may communicate with a network, such as a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial Radio Access network (E-UTRAN), a 5G Core (5G Core, 5GC), or with a RAN established through one or more BSs.

[0043] It should be noted that in the present application, UE may include but is not limited to a mobile station, a mobile terminal or device, or a user communication radio terminal. UE may be a portable radio device, including but not limited to a mobile phone, a tablet computer, a wearable device, a sensor, a vehicle, or a personal digital assistant (PDA) with wireless communication capabilities. UE may be configured to receive signals over an air interface and send signals to one or more cells in the RAN.

[0044] The BS may be configured to provide communication services according to at least a Radio Access Technology (RAT), such as Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile (GSM), commonly referred to as 2G, GSM Enhanced GSM Evolution (EDGE) RAN (GERAN), General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS), commonly referred to as 3G based on basic Wideband-Code Division Multiple Access (W-CDMA), high-speed packet access (HSPA), LTE, LTE-A, evolved / enhanced LTE (eLTE), i.e., LTE connected to 5GC, NR (commonly referred to as 5G) and / or LTE-A Pro. However, the scope of the present application is not limited to these protocols.

[0045] BS may include but is not limited to a node B (NB) in UMTS, an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a base station controller (BSC) in GSM / GERAN, an ng-eNB in ​​an Evolved Universal Terrestrial Radio Access (E-UTRA) BS related to 5GC, a next-generation eNB (ng-eNB) in 5G-RAN, and any other device capable of controlling radio communications and managing radio resources within a cell. A BS may provide services to one or more UEs via a radio interface.

[0046] The BS can provide wireless coverage to a specific geographic area using multiple cells forming a wireless access NW. The BS supports the operation of the cells. Each cell can be used to provide services to at least one UE within its wireless coverage. More specifically, each cell (commonly referred to as a service cell) provides services to serve one or more UEs within its wireless coverage (for example, each cell schedules downlink (DL) and optional uplink (UL) resources to at least one UE within its wireless coverage for DL ​​and optional UL data packet transmission). The BS can communicate with one or more UEs in a wireless communication system through multiple cells. The cell can allocate sidelink (SL) resources to support proximity services (Proximity Service, ProSe) or vehicle to everything (V2X) services. Each cell may have a coverage area that overlaps with other cells.

[0047] As mentioned above, the NR frame structure supports flexible configuration to adapt to various next-generation (e.g. 5G) communication requirements, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra-reliable and low-latency communication (URLLC), while meeting high reliability, high data rate and low latency requirements. rd The Orthogonal Frequency-Division Multiplexing (OFDM) technology agreed upon in the 3rd Generation Partnership Project (3GPP) can serve as the baseline for the NR waveform. Scalable OFDM parameter sets such as adaptive subcarrier spacing, channel bandwidth, and cyclic prefix (CP) can also be used. In addition, two coding schemes for NR are considered: (1) Low-Density Parity-Check (LDPC) and (2) Polar Code. The coding scheme adaptability can be configured based on channel conditions and / or service applications.

[0048] In addition, it is also considered that the transmission time interval TX of a single NR frame should at least include DL transmission data, protection interval and UL transmission data, where the various parts of DL transmission data, protection interval and UL transmission data should also be configurable, such as NR-based NW dynamics. In addition, SL resources can also be provided in the NR frame to support ProSe services or V2X services.

[0049] In addition, the terms "system" and "NW" in this document can be used interchangeably. The term "and / or" in this document only describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean that A exists alone, A and B exist at the same time, or B exists alone. In addition, the character " / " in this document generally indicates that the previous associated object and the next associated object are in an "or" relationship. Multiple PLMNs can operate on unlicensed spectrum. Multiple PLMNs can share the same unlicensed carrier. PLMNs can be public or private. Public PLMNs can be (but not limited to) operators or virtual operators that provide radio services to public users. Public PLMNs can own licensed spectrum and also support radio access technologies on licensed spectrum. Private PLMNs can be (but not limited to) micro-operators, factories or enterprises that provide radio services to their private users (e.g., employees or machines). In some embodiments, the public PLMN may support more deployment scenarios (e.g., carrier aggregation between licensed band NR (PCell) and NR-U (SCell), dual connectivity between licensed band LTE (PCell) and NR-U (PSCell), independent NR-U, NR cell with DL in unlicensed band and UL in licensed band, dual connectivity between licensed band NR (PCell) and NR-U (PSCell)). In some embodiments, the private PLMN mainly supports (but is not limited to) independent unlicensed wireless access technology (e.g., independent NR-U).

[0050] Figure 1 Shown is a diagram of a non-terrestrial network (NTN) of an exemplary embodiment of the present application.

[0051] refer to Figure 1 , the NTN may provide non-terrestrial NR access for the UE through the NTN payload 110 and the NTN gateway (GW) 120 constituting the gNB 100. A service link may be established between the NTN payload 110 and the UE 130, and a feeder link may be established between the NTN GW 120 and the NTN payload 110.

[0052] Figure 2 Shown is NTN for transparent NTN payload according to one of the exemplary embodiments of the present application.

[0053] refer to Figure 2, the next generation Node B (gNB) 200 can be divided into a non-NTN infrastructure gNB function 210 and an NTN service link configuration system 220. The NTN infrastructure 300 can be divided into two components: the NTN service link configuration system 220 and the NTN control function 310. The NTN service link configuration system 220 may include one or more NTN payloads 221 and one or more NTN GW223.

[0054] Three types of service links can be supported:

[0055] (1) Geofixed: These types of service links can be provided by beams that always continuously cover the same geographic area (e.g., GeoSynchronous Orbit (GSO) satellites).

[0056] (2) Quasi-Geofixed: These types of service links can be provided by beams that cover one geographic area for a limited time and a different geographic area for another time period (e.g., Non-GeoSynchronous Orbit (NGSO) satellites with steerable beams).

[0057] (3) Earth Mobile: These types of service links may be provided by beams whose coverage area slides over the surface of the Earth (eg, NGSO satellites with fixed or non-steerable beams).

[0058] Using NGSO satellites, gNBs can provide quasi-geo-fixed or geo-mobile service links. Conversely, gNBs operating using GSO satellites can provide geo-fixed service links.

[0059] In some implementations, the NTN-enabled UE may have GNSS functionality.

[0060] In some implementations, an NTN-enabled UE may not have GNSS functionality.

[0061] In some embodiments, system information block type 19 (SIB19) may include satellite assistance information for NTN access.

[0062] To accommodate propagation delays in NTNs, several timing relationships can be enhanced by a common timing advance (TA) and two scheduling offsets: K_offset and K_mac.

[0063] The common TA may be configured to correspond to an offset of the round-trip time (RTT) between a reference point (RP) and the NTN payload.

[0064] K_offset can be configured as a scheduling offset, which must be greater than or equal to the sum of the service link RTT and the public TA.

[0065] K_mac can be configured with an offset that needs to be greater than or equal to the RTT between the RP and the gNB.

[0066] DL and UL transmissions can be frame aligned at the UL timing synchronization RP, with an offset determined by N TA,offset g is given.

[0067] The offset K_mac can be used to delay the application of the DL configuration indicated by the medium access control (MAC) control element (CE) command on the physical downlink shared channel (PDSCH) and estimate the UE-gNB RTT. The network can provide the offset K_mac when the DL and UL frame timing are not consistent at the gNB. The offset K_mac can also be used in the random access (RA) procedure to determine the start time of the random access response (RAR) / MsgB window after the transmission of Msg1 / MsgA.

[0068] For the serving cell, the network may broadcast valid ephemeris information and common TA parameters. Before connecting to the NTN cell, the UE may have a valid Global Navigation Satellite System (GNSS) position as well as ephemeris and common TA. To achieve synchronization, the UE may determine the RTT between itself (e.g., UE) and the RP based on the GNSS position, ephemeris, and common TA parameters before and during connection to the NTN cell, and may (e.g., autonomously) pre-compensate the timing advance T of the RTT between the UE and the RP. TA The UL frame number i from the UE for transmission may be T ahead of the start of the corresponding DL frame at the UE. TA start.

[0069] The UE may determine the frequency Doppler shift of the serving link and pre-compensate the frequency Doppler shift in the uplink transmission (e.g., autonomously) by taking into account the UE's position and ephemeris. If the UE does not have a valid GNSS position and / or valid ephemeris and a common TA, the UE may not transmit until a valid GNSS position and / or valid ephemeris and a common TA are regained.

[0070] In connected mode, the UE may continuously update TA and frequency pre-compensation. The UE may be configured to report TA during the RA procedure or in connected mode. In connected mode, event-triggered TA reporting may be supported.

[0071] While the UE may pre-compensate for the instantaneous Doppler shift experienced on the serving link, the management of the Doppler shift and transponder frequency error experienced on the feeder link may be left to the network implementation.

[0072] During mobility between the NTN and the terrestrial network (TN), the UE may not need to be connected to both the NTN and the TN simultaneously.

[0073] It should be noted that NTN TN handover may include mobility in two directions, such as from NTN to TN (eg, hand-in) and from TN to NTN (eg, hand-out).

[0074] The UE can support mobility between gNBs operating NTN payloads on different orbits (e.g., in GSO and NGSO at different altitudes).

[0075] Regarding conditional handover (CHO), NTN can support the following trigger conditions, according to which the UE can perform CHO to the candidate cell:

[0076] (1) Event A4 based on RRM measurements;

[0077] (2) time-based trigger conditions; and / or

[0078] (3) Location-based trigger conditions.

[0079] A time-based or location-based trigger condition can always be configured together with one of the multiple measurement-based trigger conditions (eg, CHO events A3 / A4 / A5).

[0080] How to evaluate time-based or location-based triggering conditions and RRM measurement-based events may depend on the UE implementation.

[0081] The network can be configured:

[0082] (1) Multiple synchronization signal block (SSB) measurement timing configurations (SMTC) per carrier and a given set of cells in parallel, based on UE capabilities;

[0083] (2) Measurement gaps based on multiple SMTCs;

[0084] (3) Auxiliary information (e.g., ephemeris, common TA parameters) provided in System Information Block Type 19 (SIB19) to enable the UE to measure neighboring cells in RRC_IDLE, RRC_INACTIVE, or RRC_CONNECTED states.

[0085] NW controlled SMTC adjustment can be based on the assistance information reported in RRC_CONNECTED state. A UE in RRC_IDLE or RRC_INACTIVE state can adjust the SMTC based on the UE's location and the assistance information in SIB19.

[0086] The auxiliary information (for example, may also be referred to as UE auxiliary information in the present application) may include a service link propagation delay difference between a serving cell and a neighboring cell.

[0087] For a UE in idle or inactive mode, whether to perform NTN neighbor cell measurements on cells indicated in system information type 4 (SIB4) but not included in SIB19 may depend on the UE implementation.

[0088] For a UE in connected mode, whether to perform NTN neighbor cell measurements on cells included in the measurement configuration but not included in SIB19 may depend on the UE implementation.

[0089] In the quasi-geo-fixed cell scenario, the UE can perform time-based and location-based measurements on neighboring cells in the RRC_IDLE or RRC_INACTIVE state. Timing information and location information associated with the serving cell can be provided in SIB19. The timing information may include the coordinated universal time (UTC) when the serving cell stops serving the current geographic area. The location information may include a reference location of the serving cell and a distance threshold to the reference location.

[0090] In some embodiments, "NTN GW*" means that it may include Figure 1 The NTN GW120 shown in Figure 2 The NTN GW 223 shown in FIG. 1 and / or the NTN GW 223 shown in FIG. Figure 2 The non-NTN infrastructure gNB functionality 210 shown in FIG.

[0091] In some embodiments, the gNB denoted as “gNB#1” may include an NTN GW, and a service cell provided via a source cell (e.g., the first satellite SAT#1), and / or a service cell provided by the first satellite SAT#1, for example, before satellite switching.

[0092] In some embodiments, the gNB denoted as "gNB#2" may include an NTN GW, and a service cell provided by a target cell (e.g., a second satellite SAT#2), and / or a service cell provided by a second satellite SAT#2, for example, after a satellite handover.

[0093] In some embodiments, the security keys used by the UE for access stratum (AS) security between the UE and the gNB may not change. For example, the security keys may be the same before and after the serving satellite switch.

[0094] In some embodiments, the UE may regard the gNB before the serving satellite is switched as the first satellite SAT#1, and the UE may regard the gNB after the serving satellite is switched as the second satellite SAT#2.

[0095] In some embodiments, if the UE receives the duration of the timer, the UE may set the corresponding timer and set the initial value to the duration. When one or more conditions are met, the UE may start the timer and then reduce the timer over time. When the value of the timer reaches zero, the UE may consider / determine that the timer has expired and / or may stop the timer. When one or more conditions are met, the UE may also stop the timer.

[0096] In some embodiments, if the UE receives the duration of the timer, the UE may set the initial value of the corresponding timer to zero. When one or more conditions are met, the UE may start the timer and then increase the timer over time. When the value of the timer reaches the value of the duration, the UE may consider / determine that the timer has expired and / or may stop the timer. When one or more conditions are met, the UE may also stop the timer.

[0097] In some embodiments, if the UE receives the duration of the timer, the UE may start the timer when one or more conditions are met. After the duration starting from the time when the UE starts the timer, the UE may consider / determine that the timer has expired and / or may stop the timer. The UE may also stop the timer when one or more conditions are met.

[0098] Figure 3 Shown is a diagram of soft satellite switching in a quasi-geo-fixed cell scenario according to an exemplary embodiment of the present application.

[0099] refer to Figure 3, at time t1, the UE may be served by the network through the first (e.g., source) satellite SAT#1. At time t2, before the first satellite SAT#1 switches to the next coverage area of ​​the first satellite SAT#1, the second (e.g., target) satellite SAT#2 may start providing coverage for the same area currently covered by the first satellite SAT#1. Both the first satellite SAT#1 and the second satellite SAT#2 may be connected to the same NTN GW* through their respective feeder links, allowing the UE to potentially be covered by both satellites. At time t3, after the first satellite SAT#1 moves to the next coverage area, the UE may be served by the NW only through the second satellite SAT#2.

[0100] It should be noted that when the UE is in the coverage of the first satellite SAT#1 and the second satellite SAT#2 at the same time, the UE can be served by the NW through one or both satellites.

[0101] From the perspective of the UE, in some implementations, the physical cell identity (PCI) before and after the satellite switching may be the same, while in some other implementations, the PCI before and after the satellite switching may be different.

[0102] From the perspective of the UE, in some embodiments, the center frequency of the SSB sent by the NW through the first satellite SAT#1 and the center frequency of the SSB sent by the NW through the second satellite SAT#2 may be the same. In other embodiments, the center frequency of the SSB sent by the NW through the first satellite SAT#1 and the center frequency of the SSB sent by the NW through the second satellite SAT#2 may be different.

[0103] From the perspective of the UE, in some embodiments, the subcarrier spacing (SCS) of the SSB sent by the NW through the first satellite SAT#1 and the SCS of the SSB sent by the NW through the second satellite SAT#2 may be the same, while in some other embodiments, the subcarrier spacing (SCS) of the SSB sent by the NW through the first satellite SAT#1 and the SCS of the SSB sent by the NW through the second satellite SAT#2 may be different.

[0104] From the perspective of the UE, in some implementations, the carrier frequency or center frequency of the service cell provided by the first satellite SAT#1 and the second satellite SAT#2 may be the same, while in some other implementations, the carrier frequency or center frequency of the service cell provided by the first satellite SAT#1 and the second satellite SAT#2 may be different.

[0105] From the perspective of the UE, in some implementations, the bandwidth of the service cell provided by the first satellite SAT#1 and the bandwidth of the service cell provided by the second satellite SAT#2 may be the same, while in some other implementations, the bandwidth of the service cell provided by the first satellite SAT#1 and the bandwidth of the service cell provided by the second satellite SAT#2 may be different.

[0106] Figure 4 Shown is a diagram of hard satellite handover in a quasi-geo-fixed cell scenario according to an exemplary embodiment of the present application.

[0107] refer to Figure 4 , at time t1, the UE may be served by the network via the first (eg, source) satellite SAT#1.

[0108] refer to Figure 4 , at time t2, before the first satellite SAT#1 switches to the next coverage area of ​​the first satellite SAT#1, the second (e.g., target) satellite SAT#2 may start providing coverage for the same area currently covered by the first satellite SAT#1. From the UE's perspective, there may be a coverage gap, which means that the UE may not be served by the network in the coverage gap. Both the first satellite SAT#1 and the second satellite SAT#2 may be connected to the same NTN GW* via their respective feeder links.

[0109] In some embodiments, when this occurs, the UE may initiate a Radio Link Failure (RLF) procedure. In some embodiments, the network may instruct the UE not to initiate an RLF procedure for a certain time duration configured / indicated / determined by the network based on the expected duration of the coverage gap.

[0110] refer to Figure 4 At time t3, after the first satellite SAT#1 moves to the next coverage area, the second satellite SAT#2 may start to provide coverage for the area covered by the first satellite SAT#1 before switching the coverage area (e.g., the area where the UE is operating). During time t3, the UE may be served by the network through the second satellite SAT#2.

[0111] From the perspective of the UE, in some implementations, the PCIs before and after the satellite switching may be the same, while in some other implementations, the PCIs before and after the satellite switching may be different or the same.

[0112] From the perspective of the UE, in some embodiments, the center frequency of the SSB sent by the network through the first satellite SAT#1 and the center frequency of the SSB sent by the network through the second satellite SAT#2 may be the same, while in some other implementations, the center frequency of the SSB sent by the network through the first satellite SAT#1 and the center frequency of the SSB sent by the network through the second satellite SAT#2 may be different.

[0113] From the perspective of the UE, in some embodiments, the SCS of the SSB sent by the network through the first satellite SAT#1 and the SCS of the SSB sent by the network through the second satellite SAT#2 may be the same, while in some other embodiments, the SCS of the SSB sent by the network through the first satellite SAT#1 and the SCS of the SSB sent by the network through the second satellite SAT#2 may be different.

[0114] From the perspective of the UE, in some implementations, the carrier frequency or center frequency of the service cell provided by the first satellite SAT#1 and the second satellite SAT#2 may be the same, while in some other implementations, the carrier frequency or center frequency of the service cell provided by the first satellite SAT#1 and the second satellite SAT#2 may be different.

[0115] From the perspective of the UE, in some embodiments, the bandwidth of the service cell provided by the first satellite SAT#1 and the bandwidth of the service cell provided by the second satellite SAT#2 may be the same, while in some other embodiments, the bandwidth of the service cell provided by the first satellite SAT#1 and the bandwidth of the service cell provided by the second satellite SAT#2 may be different.

[0116] In some embodiments, if the PCI remains unchanged after the satellite switch, the UE may regard the post-switch state of the serving cell as the original serving cell, even though the switch may result in a configuration change. This situation may be referred to as "serving satellite switch with unchanged PCI". This situation may be beneficial to the entire network system in reducing latency and signaling overhead, especially if Layer 1 / Layer 2 (L1 / L2) signaling is used instead of Layer 3 (L3) signaling. This is because L3 signaling generally requires longer latency and higher signaling overhead than L1 / L2 signaling.

[0117] In some embodiments, L3 signaling may include RRC signaling or other higher layer signaling relative to MAC layer and physical layer signaling.

[0118] In some embodiments, L1 / L2 signaling may involve MAC CE, downlink control information (DCI) and / or uplink control information (UCI).

[0119] In some implementations, UE capabilities related to soft satellite handover may include:

[0120] (1) Supporting maintenance of two or more DL and / or UL timing and frequency synchronization with two satellites, such as an NTN serving cell provided by a serving satellite and an NTN serving cell provided by a neighboring satellite;

[0121] (2) Support receiving indication #1;

[0122] (3) Support network control schemes, such as receiving indication #2; and / or

[0123] (4) Support UE-initiated solutions, such as measuring SSBs with the same PCI but from different gNBs, cells or satellites.

[0124] In some implementations, it may be assumed that the UE supports the capabilities required for both hard and soft satellite handovers.

[0125] Figure 5 Shown is a signaling diagram of a signaling-based network-controlled satellite switching process according to an exemplary embodiment of the present application.

[0126] Figure 5 FIG. 4 shows a satellite handover process of NW control based on signaling in an NTN scenario, where the PCI is unchanged. The satellite handover can be, for example, a soft or hard satellite handover. In some embodiments, Figure 5 Some of the "messages" shown in may optionally not exist. In some embodiments, Figure 5 The process shown in can include Figure 5 In some embodiments, Figure 5 The "message" represented by the solid arrow may include any message, such as SIB, pre-configuration settings, indication #1, L1 and / or L3 measurement results of the second (e.g., target) satellite SAT #2, and indication #2. In some embodiments, Figure 5 The “user data” represented by the double-dot arrow may represent the transmission of UE data between entities connected by the double-dot arrow.

[0127] refer to Figure 5 , in action 501, the UE may receive one or more SIBs broadcast by the NW.

[0128] In some embodiments, the received SIBs may include SIB19, system information block type 2 (SIB2), system information block type 3 (SIB3), and / or SIB4.

[0129] In some embodiments, the received SIB may include satellite assistance information of the serving satellite / NTN serving cell. The satellite assistance information may include one or more of NTN-Config, time information, reference position, distance threshold, one or more satellite identifications (IDs), and a list of neighboring NTN cells.

[0130] In some embodiments, the NTN-Config may include an RRC information element (IE). The NTN-Config may be associated with the cell / gNB that broadcasts the SIB. The NTN-Config may include one or more of the following:

[0131] (1) The ephemeris of the source satellite (e.g., the first satellite SAT#1), provided by the high-level parameter ephemerisInfo;

[0132] (2) Public TA parameters of the source satellite, provided by the high-level parameter ta-Info;

[0133] (3) The validity period of the source satellite’s ephemeris and common TA parameters is provided by the higher-layer parameter ntn-UlSyncValidityDuration;

[0134] (4) The epoch time of the source satellite’s ephemeris and common TA parameters, provided by the higher-level parameter epochTime; and / or

[0135] (5) The cell-specific K_offset and K_mac are provided by the higher-level parameters cellSpecificKoffset and Kmac respectively.

[0136] In some implementations, the time information may indicate when a cell provided by the NTN semi-fixed system should stop providing service for the current coverage area provided by the t-Service.

[0137] In some embodiments, the reference position may include a reference position of a serving cell provided by an NTN quasi-terrestrial fixed system.The reference position may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0138] In some implementations, the distance threshold may indicate the distance between the UE and a serving cell reference location.The threshold may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0139] In some embodiments, each satellite ID may indicate a set of satellite assistance information, or each satellite ID may be associated with a set of satellite assistance information. The satellite assistance information may be included in the NTN-Config.

[0140] In some embodiments, the neighboring NTN cell list may include the NTN-ConfigIE and / or carrier frequency (eg, provided by a higher layer parameter carrierFreq) and / or PCI (eg, provided by a higher layer parameter physCellId) and / or satellite ID of each neighboring NTN cell.

[0141] In some implementations, the number of neighboring cells in the list may be at most four.

[0142] In some implementations, the number of neighboring cells in the list may exceed four.

[0143] In some embodiments, the higher layer parameters of one or more neighboring cells may be set to the same value as the PCI of the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0144] In some embodiments, the physCellId of one or more neighboring cells may not be present, indicating that the PCI is the same as the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0145] Reference again Figure 5 , in action 502, the UE may receive one or more pre-configurations from the NW.

[0146] In some implementations, the received pre-configuration may be carried in an RRC message, such as an RRCReconfiguration message.

[0147] In some implementations, the received pre-configuration may include one or more RRC parameters / IEs.

[0148] In some implementations, if the UE receives multiple pre-configurations, each pre-configuration may be associated with a different target satellite / target NTN cell.

[0149] In some embodiments, each pre-configuration may include one or more of the following: a first indication indicating a neighboring NTN cell, a satellite ID, satellite assistance information, an SSB index of multiple SSBs, time domain information about the SSB, one or more measurement configurations, one or more SMTC configurations, information about UL power control of PUSCH and / or PUCCH and / or sounding reference signal (SRS), UL bandwidth part (BWP) ID, DL BWP ID, a second indication indicating whether the UE performs a RA procedure, a third indication indicating an N_TA value, and / or a configuration including physical random access channel (PRACH) resources.

[0150] In some embodiments, the first indication may include an indication indicating to find a neighboring NTN cell from a neighboring NTN cell list included in the SIB via the target satellite (e.g., the second satellite SAT#2) (e.g., if the target satellite (NTN cell) is included in the neighboring NTN cell list in the SIB).

[0151] In some embodiments, the SIB may be SIB19, SIB2, SIB3, or SIB4.

[0152] In some embodiments, the first indication may be an integer indicating the order of entries in the neighboring NTN cell list contained in the SIB. For example, if the first indication is "1", the satellite assistance information (e.g., NTN-Config) of the target satellite (e.g., the second satellite SAT#2) may be the NTN-Config of the first neighboring NTN cell in the list; if the indication is "2", the satellite assistance information (e.g., NTN-Config) of the target satellite may be the NTN-Config of the second neighboring NTN cell in the list; and so on.

[0153] In some implementations, the UE may use satellite assistance information associated with a satellite ID included in a pre-configuration (eg, NTN-Config) during a satellite switching process.

[0154] In some embodiments, the satellite assistance information included in the pre-configuration may include satellite assistance information of the NTN serving cell provided by a target satellite (eg, the second satellite SAT#2).

[0155] In some embodiments, the satellite assistance information included in the pre-configuration may include one or more of the following:

[0156] (1) NTN-Config RRC IE of the target satellite (e.g., the second satellite SAT#2);

[0157] (2) Satellite ID of the target satellite (e.g., the second satellite SAT#2);

[0158] (3) Time information indicating when a cell provided by the NTN quasi-fixed system should stop serving its current coverage area provided by the t-Service;

[0159] (4) The reference position of the serving cell provided by the NTN quasi-geo-fixed system. The reference position can be used to initiate location-based measurements in the RRC_IDLE and RRC_INACTIVE states; and / or

[0160] (5) Distance threshold, indicating the distance between the UE and the reference location of the serving cell. This threshold can be used to start location-based measurements in the RRC_IDLE and RRC_INACTIVE states.

[0161] In some implementations, the SSB index included in the preconfiguration may be the SSB index of the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0162] In some implementations, the SSB index of the SSB transmitted by the target satellite (eg, the second satellite SAT#2) may be represented by a bitmap.

[0163] In some embodiments, the size (number of bits) of the bitmap may be the maximum number of SSBs per half-frame (eg, 4, 8, or 64).

[0164] In some implementations, the bitmap may indicate the time domain location of the SSBs transmitted by the target satellite (eg, the second satellite SAT#2) in a half-frame.

[0165] In some implementations, the first / leftmost bit of such a bitmap may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0166] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB has not been transmitted, while a 1 value may indicate that the corresponding SSB has been transmitted.

[0167] In some implementations, the size (eg, number of bits) of the bitmap may be 8 bits.

[0168] In some embodiments, when the maximum number of SSBs per half frame is 4, only the leftmost 4 bits in the bitmap may be valid, and the UE may ignore the rightmost 4 bits in the bitmap.

[0169] In some embodiments, when the maximum number of SSBs per half frame is 8, all 8 bits in the bitmap may be valid.

[0170] In some implementations, the first / leftmost bit may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0171] In some embodiments, when the maximum number of SSBs per half-frame is 64, all 8 bits in the bitmap may be valid.

[0172] In some embodiments, the first / leftmost bit can correspond to the first SSB index in each group (e.g., SSB index 0, 8, etc.); the second bit can correspond to the second SSB index in each group (e.g., SSB index 1, 9, etc.), and so on. Each SSB group can be determined as follows: Group #1 can include SSB indexes from 0 to 7, Group #2 can include SSB indexes from 8 to 15, and so on.

[0173] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB is not transmitted, while a 1 value may indicate that the corresponding SSB is transmitted.

[0174] In some embodiments, if the NW indicates (e.g., through the RRC parameter ssb-PositionsInBurst) that the SSB index transmitted from the NTN serving cell (e.g., through the source satellite (e.g., the first satellite SAT#1)) is also indicated by the NW through the bitmap as being transmitted from the target satellite (e.g., the second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the target satellite (e.g., the second satellite SAT#2). In this case, the bitmap may override the RRC parameter ssb-PositionsInBurst when both indicate transmission of an SSB with a specific index.

[0175] In some embodiments, if the NW (e.g., through the RRC parameter ssb-PositionsInBurst) indicates through a bitmap that an SSB index transmitted from an NTN serving cell (e.g., through a source satellite (e.g., a first satellite SAT#1)) is also indicated by the NW to be transmitted from a target satellite (e.g., a second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the NTN serving cell provided by the source satellite (e.g., the first satellite SAT#1). In this case, the RRC parameter ssb-PositionsInBurst may override the bitmap when both indicate transmission of an SSB with a specific index.

[0176] In some embodiments, the UE may assume that the bitmap and the RRC parameter ssb-PositionsInBurst do not simultaneously indicate a value of 1 for the same SSB index (eg, an SSB is transmitted).

[0177] In some implementations, the time domain information included in the preconfiguration may be time domain information about the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0178] In some embodiments, the UE may assume that the SSB received during the duration indicated by the time domain information is transmitted from the target satellite (e.g., the second satellite SAT#2). When the UE is required / configured to measure the SSB of the target satellite (e.g., the second satellite SAT#2), the UE may measure the SSB received during the duration indicated by the time domain information.

[0179] In some implementations, the time domain information may be one or a combination of the following:

[0180] (1) One or more super system frame numbers (SFN);

[0181] (2) one or more SFNs;

[0182] (3) one or more subframe numbers;

[0183] (4) one or more time slot numbers; and / or

[0184] (5) One or more SSB indexes.

[0185] In some embodiments, each of the one or more measurement configurations may include one or more measurement objects, which may include the time / frequency location and SCS of the SSB of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2).

[0186] In some implementations, the one or more measurement configurations may include one or more SMTC configurations.The UE may perform measurements on SSBs received from a target satellite (eg, a second satellite SAT#2) during the SMTC window.

[0187] In some implementations, the one or more measurement configurations may include one or more CSI reporting configurations.

[0188] In some embodiments, CSI reporting may be configured as periodic, semi-persistent on a physical uplink control channel (PUCCH), semi-persistent on a physical uplink shared channel (PUSCH), or aperiodic.

[0189] In some embodiments, the reporting quantity configuration of the CSI report can be configured as "ssb-Index-RSRP", which may mean that the UE can report the reference signal received power (RSRP) of the CSI measurement through one or more SSB indices.

[0190] In some embodiments, one or more SMTC configurations included in the pre-configuration may be used for measurements on the SSB of the NTN serving cell provided by the target satellite (eg, the second satellite SAT#2).

[0191] In some embodiments, UL power control of PUSCH and / or PUCCH and / or SRS may include one or more of the following:

[0192] (1) one or more p0-alpha sets (ID);

[0193] (2) Path loss reference signal (PL-RS) ID, such as pathlossReferenceIndex, which may indicate a reference signal that the UE may use to estimate path loss and calculate UL transmission power;

[0194] (3) Nominal PUSCH power configuration, e.g., preambleReceivedTargetPower, p0-NominalWithoutGrant, p0-NominalWithGrant, p0-PUCCH-Value, which may be used by the UE to calculate the UL transmit power; and / or

[0195] (4) Index of the PUSCH power control adjustment state, which can be used by the UE to perform closed-loop power control and calculate the UL transmit power.

[0196] In some embodiments, the UL BWP ID may indicate the first active BWP ID after a satellite switch or after successfully receiving one or more indications #2.

[0197] In some embodiments, the DL BWP ID may indicate the first active BWP ID after a satellite switch or after successfully receiving one or more indications #2.

[0198] In some embodiments, the second indication may be an indication of whether the UE can (configured / authorized) perform the (2-step / 4-step) RA procedure after receiving indication #2 (e.g., a handover command), ENUMERATED is set to "{Enable}" or ENUMERATED is set to "{Enable,Disable}".

[0199] In some embodiments, the third indication may be an indication of an N_TA value that the UE may use to determine the transmission time of the preamble / MSG1 / MSGA as part of the (4-step / 2-step) RA procedure when indication #2 is received.

[0200] In some implementations, the third indication may instruct the UE to use an N_TA value equal to 0 or to use an N_TA value equal to a currently stored N_TA value.

[0201] In some implementations, the third indication may provide a specific N_TA value to the UE.

[0202] In some implementations, the configuration of the PRACH resources may include one or more of a preamble index, a time domain resource, and a frequency domain resource.

[0203] refer to Figure 5 In action 503, the coverage area of ​​the service cell provided by the target satellite (eg, the second satellite SAT#2) may begin to overlap the coverage area of ​​the service cell provided by the source satellite (eg, the first satellite SAT#1).

[0204] In action 504, the UE may receive one or more indications #1 from the NW.

[0205] In some embodiments, one or more indications #1 may indicate that the NTN service cell provided by the target satellite (eg, the second satellite SAT#2) begins to cover the coverage area of ​​the service cell provided by the source satellite (eg, the first satellite SAT#1).

[0206] In some implementations, one or more indications #1 may be transmitted via a source satellite (eg, a first satellite SAT#1).

[0207] In some implementations, one of the one or more indications #1 may include a MAC CE.

[0208] In some implementations, the UE may send a hybrid automatic repeat request (HARQ) acknowledgement (ACK) information bit in response to a decoding result (eg, indication #1) of a PDSCH carrying a MAC CE.

[0209] In some embodiments, one of the one or more indications #1 may be a group-common DCI. The group-common DCI may be a DCI with a cyclic redundancy check (CRC) scrambled by a group-common radio network temporary identifier (RNTI) (e.g., G-RNTI) or an RNTI corresponding to the NTN.

[0210] In some embodiments, one of the one or more indications #1 may be a UE-specific DCI with a CRC scrambled by a UE-specific RNTI (e.g., a cell RNTI (C-RNTI), a configured scheduling RNTI (CS-RNTI), a modulation and coding scheme RNTI (MCS-RNTI), or an NTN-specific RNTI).

[0211] In some implementations, the DCI may schedule the PDSCH.The UE may send the HARQ-ACK information bits in response to receiving the PDSCH in a time slot indicated by a field contained in the DCI (eg, the PDSCH-to-HARQ_feedback timing indicator field).

[0212] In some implementations, if the UE sends a negative acknowledgement (NACK) to the NW in response to scheduled PDSCH reception, the UE may apply the information indicated by indication #1.

[0213] In some implementations, regardless of whether the UE sends an ACK or a NACK to the NW in response to scheduled PDSCH reception, the UE may apply the information indicated by indication #1.

[0214] In some embodiments, the DCI may be a DCI without DL allocation. In other words, the DCI may not schedule PDSCH reception. In some embodiments, the NW may set one or more fields contained in the DCI to a specific value. In some embodiments, the NW may use a specific RNTI (e.g., C-RNTI, CS-RNTI, MCS-RNTI or other RNTI) to scramble the CRC of the DCI. If the UE detects that one or more fields contained in the DCI are set to a specific value and / or if the UE finds that the CRC of the DCI is scrambled by a specific RNTI, the UE can recognize that the DCI does not schedule PDSCH reception.

[0215] In some embodiments, if the UE sends HARQ information to the NW in response to DCI reception, the UE may apply the information indicated by indication #1. The HARQ information may include ACK-only, NACK-only, or ACK / NACK information. ACK-only may mean that the UE only sends ACK. NACK-only may mean that the UE only sends NACK. ACK / NACK may mean that the UE may send ACK or NACK.

[0216] In some implementations, regardless of whether the UE sends an ACK or a NACK to the NW in response to DCI reception, the UE may apply the information indicated by indication #1.

[0217] In some embodiments, the DCI may include a field to indicate which pre-configuration the UE should apply. This field may indicate a satellite ID or an indication of a neighboring NTN cell.

[0218] In some implementations, one of the one or more indications #1 may be a SIB or a part of a SIB. The SIB may be transmitted to the UE via broadcast or UE-specific dedicated control signaling.

[0219] In some embodiments, the SIB may be SIB19, SIB2, SIB3, or SIB4.

[0220] In some implementations, the NW may request the UE to re-acquire the SIB.

[0221] In some embodiments, if indication #1 is present in the SIB, the UE in the RRC_IDLE state may use the information of the target satellite (e.g., the second satellite SAT#2) indicated by indication #1 to perform initial access and / or initiate an RRC connection establishment procedure and / or a (2-step / 4-step) RA process.

[0222] In some embodiments, the UE may use the satellite assistance information indicated in indication #1 for DL ​​synchronization and UL transmission. Specifically, the UE may use the common TA parameters and the ephemeris of the target satellite (e.g., the second satellite SAT#2) to determine the TA value for UL transmission during the RA process.

[0223] In some implementations, the UE may use the SSB of the SSB index indicated by indication #1 to determine the transmission occasion (eg, PRACH occasion) of the RA preamble during the RA procedure.

[0224] In some embodiments, one or more indications #1 may include one or more of a measurement object ID, an indication of a neighboring NTN cell via a target satellite, a satellite ID, an SSB index, a frequency position, a bit indicating the presence of a target satellite, a DLBWP ID, and a UL BWPID.

[0225] In some implementations, the measurement object ID may indicate that the measurement object is configured in a pre-configuration.

[0226] In some embodiments, the indication may indicate a neighboring NTN cell via a target satellite (eg, the second satellite SAT#2) from a neighboring NTN cell list included in SIB19.

[0227] In the case where the global synchronization channel numbers (GSCN) are the same, one or more indications #1 may include an SSB index transmitted from a target satellite (eg, the second satellite SAT#2).

[0228] In the case where the GSCN is different, one or more indications #1 may include the frequency location (e.g., NR-ARFCN / E-UTRA-ARFCN) of the SSB transmitted from the target satellite (e.g., the second satellite SAT#2).

[0229] In the case where indication #1 includes DCI, indication #1 may include a bit indicating that the target satellite (e.g., the second satellite SAT #2) exists. In some embodiments, the DCI may include a 1-bit field to indicate that the target satellite (e.g., the second satellite SAT #2) exists. The DCI may be a DCI with or without DL allocation.

[0230] In some embodiments, the DL BWP ID may indicate the first active DL BWP after a satellite switch or successful reception of one or more indications #2.

[0231] In some embodiments, the UL BWP ID may indicate the first active UL BWP after satellite switching or successful reception of one or more indications #2.

[0232] Reference again Figure 5 , in action 505, the UE may perform UE action #1 (eg, upon successful reception of indication #1).

[0233] In some implementations, UE action #1 may include one or more of the following:

[0234] (1) When indication #1 includes a measurement configuration ID (e.g., MeasID), activate the indicated measurement configuration;

[0235] (2) calculating the TA value according to the common TA parameters and the ephemeris of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2);

[0236] (3) performing UL frequency synchronization according to satellite assistance information (e.g., NTN-Config) of a target satellite (e.g., a second satellite SAT#2) (e.g., satellite assistance information associated with a satellite ID indicated by preconfiguration or indication #1 or a neighboring NTN cell);

[0237] (4) performing DL synchronization (e.g., a DL synchronization procedure) according to an SSB with an SSB index belonging to a target satellite (e.g., a second satellite SAT#2) (e.g., the GSCN may be the same); and / or

[0238] (5) When indication #1 is transmitted through SIB, if a bit or one or more fields in indication #1 indicates that there is a target satellite (e.g., the second satellite SAT#2), L1 / L3 measurement is performed on the SSB sent by the target satellite (e.g., the second satellite SAT#2) or belonging to the target satellite (e.g., the second satellite SAT#2), where the SSB index of the SSB can be indicated in the SIB (e.g., SIB19, SIB2, SIB3, SIB4) or can be provided / configured in the pre-configuration.

[0239] Reference again Figure 5 In action 506, the UE may transmit / send / report the measurement result / report of the service cell provided by the target satellite (e.g., the second satellite SAT#2) to the NW on the service cell provided by the source satellite (e.g., the first satellite SAT#1) (e.g., through the reporting configuration and the measurement configuration in the pre-configuration).

[0240] In some embodiments, the UE may be further configured to perform L1 or L3 measurements on a serving cell provided by a source satellite (eg, a first satellite SAT#1). The measurement signal may include an SSB received from the source satellite (eg, a first satellite SAT#1).

[0241] In some embodiments, the measurement result / report may be a result of an L1 measurement (eg, an L1 measurement result / report).

[0242] In some embodiments, the L1 measurement result / report may be a type of uplink control information (UCI). For example, the L1 measurement result / report may include a channel state information (CSI) report.

[0243] In some embodiments, the L1 measurement result / report may be transmitted on the PUCCH or PUSCH, depending on whether the measurement result / report is a periodic, semi-persistent or aperiodic CSI report.

[0244] In some embodiments, L1 measurement and / or L1 measurement result / report may be triggered / activated by indication #1, or triggered / activated upon successful reception of indication #1.

[0245] In some embodiments, when L1 measurement / CSI reporting is configured as "semi-persistent", L1 / measurement / CSI reporting can be activated by indication # 1. In this case, UL grant (e.g., for reporting on PUSCH) or PUCCH resources (for reporting on PUCCH) can be indicated by indication # 1.

[0246] In some embodiments, the transmission of L1 measurements / reports may be triggered by one or more events.

[0247] In some embodiments, the L1 measurement report may include a satellite ID and / or SSB-RSRP and / or an SSB resource index (SSBRI).

[0248] In some implementations, the measurement result / report may be a result of an L3 measurement. The L3 measurement may be configured by pre-configuration.

[0249] In some implementations, the report type of L3 measurement may be configured as a periodic measurement report.

[0250] In some implementations, the report type of L3 measurement may be configured as an event-triggered measurement report.

[0251] In some embodiments, the event may be one of the following: event A1, event A2, event A3, event A4, event A5, event A6, event D1, conditional event A3, conditional event A4, conditional event A5, conditional event D1, and / or conditional event T1. The above events are defined as follows.

[0252] Event A1: RSRP / RSRQ / SINR of the serving cell becomes better than an absolute threshold.

[0253] Event A2: RSRP / RSRQ / SINR of the serving cell becomes worse than an absolute threshold.

[0254] Event A3: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the RSRP / RSRQ / SINR offset of the PCell / PSCell.

[0255] Event A4: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the absolute threshold.

[0256] Event A5: RSRP / RSRQ / SINR of the PCell / PSCell becomes worse than a first absolute threshold, and RSRP / RSRQ / SINR of a neighboring cell / SCell becomes better than a second absolute threshold.

[0257] Event A6: The RSRP / RSRQ / SINR offset of the neighboring cell is better than that of the SCell.

[0258] Event D1: The distance between the UE and a reference location referenceLocation1 becomes (e.g., in meters or kilometers) greater than a configured threshold distanceThreshFromReference1 (e.g., also in meters or kilometers), and the distance between the UE and another reference location referenceLocation2 becomes less than another configured threshold distanceThreshFromReference2.

[0259] Conditional event A3: The RSRP / RSRQ / SINR offset of the conditional reconfiguration candidate is better than the RSRP / RSRQ / SINR of the PCell / PSCell.

[0260] Conditional event A4: RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than the absolute threshold.

[0261] Conditional event A5: the RSRP / RSRQ / SINR of the PCell / PSCell is worse than an absolute threshold 1 (absolutethreshold1), and the RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than another absolute threshold 2 (absolute threshold2).

[0262] Conditional event D1: The distance between the UE and a reference location referenceLocation1 of the conditional reconfiguration candidate becomes greater than a configured threshold distanceThreshFromReference1, and the distance between the UE and another reference location referenceLocation2 of the conditional reconfiguration candidate becomes less than another configured threshold distanceThreshFromReference2.

[0263] Conditional event T1: The time measured at the UE becomes greater than the configured threshold t1-Threshold but less than t1-Threshold+duration, where duration can be configured by the NW.

[0264] In some embodiments, the report of the L3 measurement may include the RSRP of the SSB received from the target satellite (e.g., the second satellite SAT#2), such as the RSRP of the SSB indicated by the preconfiguration or indication #1.

[0265] In some implementations, the L3 measurement report may include RSRQ or signal-to-interference-plus-noise ratio (SINR).

[0266] In some embodiments, the L3 measurement results / reports may include the RSRP and satellite ID of the SSB.

[0267] In some embodiments, the L3 measurement result / report may include the RSRP and indication of the SSB. When the indication exists and / or is configured to have a first value, it may indicate that the L3 measurement result / report is associated with a target satellite, which is indicated in the preconfiguration or indication #1. When the indication does not exist or is configured to have a second value, it may indicate that the L3 measurement result / report is not associated with the target satellite, which is indicated in the preconfiguration or indication #1.

[0268] Reference again Figure 5 , in action 507, the UE may receive one or more indications #2 from the NW.

[0269] In some implementations, indication #2 may include a satellite handover command.

[0270] In some implementations, indication #2 may be a MAC CE.

[0271] In some implementations, indication #2 may be a UE-specific DCI with a CRC scrambled by a UE-specific RNTI (eg, C-RNTI, CS-RNTI, MCS-RNTI, or NTN-specific RNTI).

[0272] In some implementations, indication #2 may be a group common DCI with a CRC scrambled by a group common RNTI or an NTN specific RNTI.

[0273] In some implementations, the received one or more indications #2 may include one or more of an indication, information related to UL power control, a DL BWP ID, a UL BWP ID, and a preamble index.

[0274] In some embodiments, the indication may be a beam indication of a specific channel and / or a specific reference signal (eg, a transmission configuration indicator (TCI) status).

[0275] In some implementations, the DL BWP ID may indicate the first active DLBWP after successful reception of indication #2.

[0276] In some implementations, the UL BWP ID may indicate the first active ULBWP after successful reception of indication #2.

[0277] Reference again Figure 5In action 508, the UE may send (eg, via an RRC message or ARQ / HARQ ACK information) an acknowledgement of indication #2 (eg, upon successful reception of indication #2) to the NW. In some implementations, the UE may perform UE action #2.

[0278] In some implementations, UE action #2 may include one or more of the following:

[0279] (1) Apply the beam indication (e.g., TCI state) indicated by indication #2 or provided by preconfiguration for the next UL transmission and / or DL ​​reception;

[0280] (2) Apply the UL power control related information for the next UL transmission indicated by indication #2 or provided by pre-configuration;

[0281] (3) Switch the active DL BWP according to the DL BWP ID indicated by indication #2 / pre-configuration;

[0282] (4) Switch the active UL BWP according to the UL BWP ID indicated by indication #2 / pre-configuration;

[0283] (5) Re-acquiring system information (e.g., SIB1 and / or other SIBs, such as SIB19), for example, regardless of whether the corresponding valueTag has changed;

[0284] (6) performing RACH-based actions: in the case where indication #1, indication #2 and / or pre-configuration indicate that the UE performs the RA procedure, performing the RA procedure and sending a preamble, where N_TA is equal to 0, the common TA is equal to the value calculated from the common TA parameters of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2), and the UE-specific TA is equal to the value calculated from the ephemeris of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2); and / or

[0285] (7) When indication #1, indication #2 and / or pre-configuration indicates that the UE performs the RA procedure, the RA procedure is performed and a preamble is sent with N_TA equal to the value of indication #1 / indication #2 / pre-configuration indication.

[0286] In some implementations, when preconfiguration or indication #2 provides / indicates a preamble index, the UE may use the provided / indicated preamble index for preamble transmission.

[0287] In some implementations, preconfiguration or indication #2 may provide / indicate time domain and / or frequency domain resources for PRACH transmission.

[0288] In some implementations, the UE may first transmit an acknowledgement of indication #2 to the NW and then perform UE operation #2.

[0289] In some implementations, the UE may first perform UE operation #2 and then transmit a confirmation of indication #2 to the NW.

[0290] In some embodiments, when the UE successfully decodes indication #2, the UE may transmit an ACK (e.g., HARQ-ACK information bit "1") to the NW via a source satellite (e.g., the first satellite SAT#1) or via a target satellite (e.g., the second satellite SAT#2).

[0291] In some implementations, if the UE cannot decode indication #2, the UE may send a NACK (eg, HARQ-ACK information bit "0") to the NW or NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0292] In the case where indication #2 is a MAC CE, in some embodiments, if the UE successfully decodes indication #2 and sends HARQ-ACK information in time slot n corresponding to the PDSCH carrying indication #2, the UE can receive the HARQ-ACK information from n+ The information (e.g., indicated by indication #1) or configuration (e.g., provided in the pre-configuration) is applied starting from the first time slot after , where μ may be the SCS configuration of the PUCCH, and μ Kmac It can be k mac The SCS configuration is 0 for FR1, or 2 or 3 for FR2, and k mac may be provided by K-Mac (e.g., K_mac as described above), or if K-Mac is not provided, k mac can be equal to 0. In this case, is equal to 1, is equal to 2, is equal to 4, is equal to 8, and Equals 16.

[0293] Reference again Figure 5 , after action 509, the UE may start to be served by the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2); and in action 509, the NTN service cell may stop providing service for the current coverage area by the source satellite (e.g., the first satellite SAT#1) and may switch to the next coverage area.

[0294] Figure 6 Shown is a signaling diagram of a time-based network-controlled satellite switching process according to an exemplary embodiment of the present application.

[0295] Figure 6 FIG. 4 is a diagram showing a time-based NW controlled satellite switching process with constant PCI in an NTN scenario. The satellite switching can be, for example, a soft or hard satellite switching. In some embodiments, Figure 6 Some of the "messages" shown in may optionally not exist. In some embodiments, Figure 6 The process shown in can include Figure 6 In some embodiments, Figure 6 The "message" represented by the solid arrow may include any message, such as SIB, pre-configuration settings, indication #1, and L1 and / or L3 measurement results of the second (e.g., target) satellite SAT #2. Figure 6 The “user data” represented by the double-dot arrows may represent the transmission of UE data between entities connected by the double-dot arrows.

[0296] refer to Figure 6 , in action 601, the UE may receive one or more SIBs broadcast by the NW.

[0297] In some embodiments, the received SIB may include SIB19, SIB2, SIB3, and / or SIB4.

[0298] In some embodiments, the received SIB may include satellite assistance information of the serving satellite / NTN serving cell. The satellite assistance information may include one or more of NTN-Config, time information, reference position, distance threshold, one or more satellite IDs, and a list of neighboring NTN cells.

[0299] In some embodiments, NTN-Config may be an RRC IE. NTN-Config may be associated with the cell / gNB that broadcasts the SIB. NTN-Config may include one or more of the following:

[0300] (1) The ephemeris of the source satellite, provided by the high-level parameter ephemerisInfo;

[0301] (2) Public TA parameters of the source satellite, provided by the high-level parameter ta-Info;

[0302] (3) The validity period of the source satellite’s ephemeris and common TA parameters is provided by the higher-layer parameter ntn-UlSyncValidityDuration;

[0303] (4) The epoch time of the source satellite’s ephemeris and common TA parameters, provided by the higher-level parameter epochTime; and / or

[0304] (5) The cell-specific K_offset and K_mac are provided by the higher-level parameters cellSpecificKoffset and Kmac respectively.

[0305] In some implementations, the time information may indicate when a cell provided by the NTN semi-fixed system should stop providing service for the current coverage area provided by the t-Service.

[0306] In some embodiments, the reference position may include a reference position of a serving cell provided by an NTN quasi-terrestrial fixed system.The reference position may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0307] In some implementations, the distance threshold may indicate the distance between the UE and a serving cell reference location.The threshold may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0308] In some embodiments, each satellite ID may indicate a set of satellite assistance information, or each satellite ID may be associated with a set of satellite assistance information. The satellite assistance information may be included in the NTN-Config.

[0309] In some embodiments, the neighboring NTN cell list may include the NTN-ConfigIE and / or carrier frequency (eg, provided by a higher layer parameter carrierFreq) and / or PCI (eg, provided by a higher layer parameter physCellId) and / or satellite ID of each neighboring NTN cell.

[0310] In some implementations, the number of neighboring cells in the list may be at most four.

[0311] In some implementations, the number of neighboring cells in the list may exceed four.

[0312] In some embodiments, the higher layer parameters of one or more neighboring cells may be set to the same value as the PCI of the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0313] In some embodiments, the physCellId of one or more neighboring cells may not be present, indicating that the PCI is the same as the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0314] Reference again Figure 6 , in action 602, the UE may receive one or more pre-configurations from the NW.

[0315] In some implementations, the received pre-configuration may be carried in an RRC message, such as an RRCReconfiguration message.

[0316] In some implementations, the received pre-configuration may include one or more RRC parameters / IEs.

[0317] In some implementations, if the UE receives a pre-configuration, the received pre-configuration may be associated with a target satellite / target NTN cell.

[0318] In some implementations, if the UE receives multiple pre-configurations, each pre-configuration may be associated with a different target satellite / target NTN cell.

[0319] In some embodiments, each pre-configuration may include one or more of the following: a first indication indicating a neighboring NTN cell, a satellite ID, satellite assistance information, an SSB index of multiple SSBs, time domain information about the SSB, one or more measurement configurations, one or more SMTC configurations, information about UL power control of PUSCH and / or PUCCH and / or sounding reference signal (SRS), UL bandwidth part (BWP) ID, DL BWP ID, a second indication indicating whether the UE performs a RA procedure, a third indication indicating an N_TA value; including a configuration of a physical random access channel (PRACH) resource; a timestamp; and / or the duration of a first timer.

[0320] In some embodiments, the first indication may include an indication indicating to find a neighboring NTN cell from a neighboring NTN cell list included in the SIB via the target satellite (e.g., the second satellite SAT#2) (e.g., if the target satellite (NTN cell) is included in the neighboring NTN cell list in the SIB).

[0321] In some embodiments, the SIB may be SIB19, SIB2, SIB3, or SIB4.

[0322] In some embodiments, the first indication may be an integer indicating the order of entries in the neighboring NTN cell list contained in the SIB. For example, if the first indication is "1", the satellite assistance information (e.g., NTN-Config) of the target satellite (e.g., the second satellite SAT#2) may be the NTN-Config of the first neighboring NTN cell in the list; if the indication is "2", the satellite assistance information (e.g., NTN-Config) of the target satellite may be the NTN-Config of the second neighboring NTN cell in the list; and so on.

[0323] In some implementations, the UE may use satellite assistance information associated with a satellite ID included in a pre-configuration (eg, NTN-Config) during a satellite switching process.

[0324] In some embodiments, the satellite assistance information included in the pre-configuration may include satellite assistance information of the NTN serving cell provided by a target satellite (eg, the second satellite SAT#2).

[0325] In some embodiments, the satellite assistance information included in the pre-configuration may include one or more of the following:

[0326] (1) NTN-Config RRC IE of the target satellite (e.g., the second satellite SAT#2);

[0327] (2) Satellite ID of the target satellite (e.g., the second satellite SAT#2);

[0328] (3) Time information indicating when a cell provided by the NTN quasi-fixed system should stop serving its current coverage area provided by the t-Service;

[0329] (4) The reference position of the serving cell provided by the NTN quasi-geo-fixed system. The reference position can be used to initiate location-based measurements in the RRC_IDLE and RRC_INACTIVE states; and / or

[0330] (5) Distance threshold, indicating the distance between the UE and the reference location of the serving cell. This threshold can be used to start location-based measurements in the RRC_IDLE and RRC_INACTIVE states.

[0331] In some implementations, the SSB index included in the preconfiguration may be the SSB index of the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0332] In some implementations, the SSB index of the SSB transmitted by the target satellite (eg, the second satellite SAT#2) may be represented by a bitmap.

[0333] In some embodiments, the size (number of bits) of the bitmap may be the maximum number of SSBs per half-frame (eg, 4, 8, or 64).

[0334] In some implementations, the bitmap may indicate the time domain location of the SSBs transmitted by the target satellite (eg, the second satellite SAT#2) in a half-frame.

[0335] In some implementations, the first / leftmost bit of such a bitmap may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0336] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB has not been transmitted, while a 1 value may indicate that the corresponding SSB has been transmitted.

[0337] In some implementations, the size (eg, number of bits) of the bitmap may be 8 bits.

[0338] In some embodiments, when the maximum number of SSBs per half frame is 4, only the leftmost 4 bits in the bitmap may be valid, and the UE may ignore the rightmost 4 bits in the bitmap.

[0339] In some embodiments, when the maximum number of SSBs per half frame is 8, all 8 bits in the bitmap may be valid.

[0340] In some implementations, the first / leftmost bit may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0341] In some embodiments, when the maximum number of SSBs per half-frame is 64, all 8 bits in the bitmap may be valid.

[0342] In some embodiments, the first / leftmost bit can correspond to the first SSB index in each group (e.g., SSB index 0, 8, etc.); the second bit can correspond to the second SSB index in each group (e.g., SSB index 1, 9, etc.), and so on. Each SSB group can be determined as follows: Group #1 can include SSB indexes from 0 to 7, Group #2 can include SSB indexes from 8 to 15, and so on.

[0343] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB is not transmitted, while a 1 value may indicate that the corresponding SSB is transmitted.

[0344] In some embodiments, if the NW indicates (e.g., through the RRC parameter ssb-PositionsInBurst) that the SSB index transmitted from the NTN serving cell (e.g., through the source satellite (e.g., the first satellite SAT#1)) is also indicated by the NW through the bitmap as being transmitted from the target satellite (e.g., the second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the target satellite (e.g., the second satellite SAT#2). In this case, the bitmap may override the RRC parameter ssb-PositionsInBurst when both indicate transmission of an SSB with a specific index.

[0345] In some embodiments, if the NW (e.g., through the RRC parameter ssb-PositionsInBurst) indicates through a bitmap that an SSB index transmitted from an NTN serving cell (e.g., through a source satellite (e.g., a first satellite SAT#1)) is also indicated by the NW to be transmitted from a target satellite (e.g., a second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the NTN serving cell provided by the source satellite (e.g., the first satellite SAT#1). In this case, the RRC parameter ssb-PositionsInBurst may override the bitmap when both indicate transmission of an SSB with a specific index.

[0346] In some embodiments, the UE may assume that the bitmap and the RRC parameter ssb-PositionsInBurst do not simultaneously indicate a value of 1 for the same SSB index (eg, an SSB is transmitted).

[0347] In some implementations, the time domain information included in the preconfiguration may be time domain information about the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0348] In some embodiments, the UE may assume that the SSB received during the duration indicated by the time domain information is transmitted from the target satellite (e.g., the second satellite SAT#2). When the UE is required / configured to measure the SSB of the target satellite (e.g., the second satellite SAT#2), the UE may measure the SSB received during the duration indicated by the time domain information.

[0349] In some implementations, the time domain information may be one or a combination of the following:

[0350] (1) One or more super system frame numbers (SFN);

[0351] (2) one or more SFNs;

[0352] (3) one or more subframe numbers;

[0353] (4) one or more time slot numbers; and / or

[0354] (5) One or more SSB indexes.

[0355] In some embodiments, each of the one or more measurement configurations may include one or more measurement objects, which may include the time / frequency location and SCS of the SSB of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2).

[0356] In some implementations, the one or more measurement configurations may include one or more SMTC configurations.The UE may perform measurements on SSBs received from a target satellite (eg, a second satellite SAT#2) during the SMTC window.

[0357] In some implementations, the one or more measurement configurations may include one or more CSI reporting configurations.

[0358] In some implementations, CSI reporting may be configured as periodic, semi-persistent on PUCCH, semi-persistent on PUSCH, or aperiodic.

[0359] In some embodiments, the reporting quantity configuration of the CSI report can be configured as "ssb-Index-RSRP", which may mean that the UE can report the reference signal received power (RSRP) of the CSI measurement through one or more SSB indices.

[0360] In some embodiments, one or more SMTC configurations included in the pre-configuration may be used for measurements on the SSB of the NTN serving cell provided by the target satellite (eg, the second satellite SAT#2).

[0361] In some embodiments, UL power control of PUSCH and / or PUCCH and / or SRS may include one or more of the following:

[0362] (1) one or more p0-alpha sets (ID);

[0363] (2) Path loss reference signal (PL-RS) ID, such as pathlossReferenceIndex, which may indicate a reference signal that the UE may use to estimate path loss and calculate UL transmission power;

[0364] (3) Nominal PUSCH power configuration, e.g., preambleReceivedTargetPower, p0-NominalWithoutGrant, p0-NominalWithGrant, p0-PUCCH-Value, which may be used by the UE to calculate the UL transmit power; and / or

[0365] (4) Index of the PUSCH power control adjustment state, which can be used by the UE to perform closed-loop power control and calculate the UL transmit power.

[0366] In some implementations, the UL BWP ID may indicate the first active BWP ID after satellite switching or after event #1 is satisfied.

[0367] In some implementations, the UL BWP ID may indicate the first active BWP ID after satellite switching or after event #1 is satisfied.

[0368] In some embodiments, the second indication may be an indication of whether the UE can (configured / authorized) perform the (2-step / 4-step) RA procedure when event #1 is satisfied, ENUMERATED is set to "{Enabled}" or ENUMERATED is set to "{Enabled,Disabled}".

[0369] In some implementations, the third indication may be an indication of an N_TA value that the UE may use to determine the transmission time of the preamble as part of the RA procedure when event #1 is met.

[0370] In some implementations, the third indication may instruct the UE to use an N_TA value equal to 0 or to use an N_TA value equal to a currently stored N_TA value.

[0371] In some implementations, the third indication may provide a specific N_TA value to the UE.

[0372] In some implementations, the configuration of the PRACH resources may include one or more of a preamble index, a time domain resource, and a frequency domain resource.

[0373] In some embodiments, the timestamp may indicate the time when the UE switches from the source satellite (e.g., the first satellite SAT#1) to the target satellite (e.g., the second satellite SAT#2). For example, the timestamp may indicate the time when the coverage area of ​​the service cell provided by the target satellite (e.g., the second satellite SAT#2) begins to overlap the coverage area of ​​the service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0374] In some implementations, the timestamp may indicate a time that is a multiple of 10 milliseconds after 00:00:00 (Gregorian calendar) January 1, 1900. The exact switching time may be between the time indicated by the value of the timestamp minus 1 and the time indicated by the value of the timestamp.

[0375] In some implementations, the timestamp may use a combination of super SFN, SFN, and / or subframe number to indicate time.

[0376] In some implementations, the duration of the first timer (eg, represented as timer #1) may indicate an initial value of the first timer or a length of the first timer.

[0377] In some implementations, the first timer may be a timer maintained by an RRC entity or a MAC entity.

[0378] In some implementations, the unit of duration may be a time slot, a radio frame, a second, a millisecond, or a subframe.

[0379] Reference again Figure 6 In action 603, the coverage area of ​​the service cell provided by the target satellite (e.g., the second satellite SAT#2) may begin to cover the coverage area of ​​the service cell provided by the source satellite (e.g., the first satellite SAT#1); in action 604, the UE may receive one or more indications #1 from the NW.

[0380] In some embodiments, one or more indications #1 may indicate that the NTN service cell provided by the target satellite (eg, the second satellite SAT#2) begins to cover the coverage area of ​​the service cell provided by the source satellite (eg, the first satellite SAT#1).

[0381] In some implementations, one or more indications #1 may be transmitted via a source satellite (eg, a first satellite SAT#1).

[0382] In some implementations, one of the one or more indications #1 may be a MAC CE.

[0383] In some implementations, the UE may transmit HARQ-ACK information bits in response to a decoding result (eg, indication #1) of a PDSCH carrying a MAC CE.

[0384] In some implementations, one of the one or more indications #1 may be a group-common DCI. The group-common DCI may be a DCI of a CRC scrambled using a group-common RNTI (eg, G-RNTI) or an RNTI corresponding to the NTN.

[0385] In some implementations, one of the one or more indications #1 may be a UE-specific DCI with a CRC scrambled by a UE-specific RNTI (eg, C-RNTI, CS-RNTI, or MCS-RNTI).

[0386] In some implementations, the DCI may schedule the PDSCH.The UE may send the HARQ-ACK information bits in response to receiving the PDSCH in a time slot indicated by a field contained in the DCI (eg, the PDSCH-to-HARQ_feedback timing indicator field).

[0387] In some implementations, in the event that the UE sends a (eg, RRC / HARQ / ARQ) NACK message to the NW in response to scheduled PDSCH reception, the UE may apply the information indicated by indication #1.

[0388] In some implementations, regardless of whether the UE transmits (eg, RRC / HARQ / ARQ) ACK or NACK to the NW in response to the scheduled PDSCH reception, the UE may apply the information indicated by indication #1.

[0389] In some embodiments, the DCI may be a DCI without DL allocation. In other words, the DCI may not schedule PDSCH reception. In some embodiments, the NW may set one or more fields contained in the DCI to a specific value. In some embodiments, the NW may use a specific RNTI (e.g., C-RNTI, CS-RNTI, MCS-RNTI or other RNTI) to scramble the CRC of the DCI. If the UE detects that one or more fields contained in the DCI are set to a specific value and / or if the UE finds that the CRC of the DCI is scrambled by a specific RNTI, the UE can recognize that the DCI does not schedule any PDSCH reception.

[0390] In some embodiments, if the UE sends HARQ information to the NW in response to DCI reception, the UE may apply the information indicated by indication #1. It should be noted that the HARQ information may be ACK-only, NACK-only, or ACK / NACK information. ACK-only means that the UE only sends ACK. NACK-only means that the UE only sends NACK. ACK / NACK means that the UE may send ACK or NACK.

[0391] In some implementations, regardless of whether the UE sends an ACK or a NACK to the NW in response to DCI reception, the UE may apply the information indicated by indication #1.

[0392] In some embodiments, the DCI may include a field to indicate which pre-configuration the UE should apply. This field may indicate a satellite ID or an indication of a neighboring NTN cell.

[0393] In some implementations, one of the one or more indications #1 may be a SIB or a part of a SIB. The UE may receive the SIB via broadcast or UE-specific dedicated control signaling.

[0394] In some embodiments, the SIB may be SIB19, SIB1, SIB2, SIB3, or SIB4.

[0395] In some implementations, the NW may request the UE to re-acquire the SIB.

[0396] In some embodiments, if indication #1 exists in the SIB, the UE in the RRC_IDLE state can perform initial access and / or initiate an RRC connection procedure and / or RA procedure using information of the target satellite (e.g., the second satellite SAT#2) indicated by indication #1.

[0397] In some embodiments, the UE may use the satellite assistance information indicated in indication #1 for DL ​​synchronization and UL transmission. Specifically, the UE may use the common TA parameters and the ephemeris of the target satellite (e.g., the second satellite SAT#2) to determine the TA value for UL transmission during the RA process.

[0398] In some implementations, the UE may use the SSB of the SSB index indicated by indication #1 to determine the transmission occasion (eg, PRACH occasion) of the RA preamble during the RA procedure.

[0399] In some embodiments, one or more indications #1 may include one or more of the following: a measurement object ID, an indication of a neighboring NTN cell via a target satellite, an SSB index, a frequency position, a bit indicating the presence of a target satellite, a DLBWP ID, a UL BWP ID, a timestamp; and a duration of a first timer (e.g., represented as timer #1).

[0400] In some implementations, the measurement object ID may indicate that the measurement object is configured in a pre-configuration.

[0401] In some embodiments, the indication may indicate a neighboring NTN cell via a target satellite (eg, the second satellite SAT#2) from a neighboring NTN cell list included in SIB19.

[0402] In the case where the GSCN is the same, one or more indications #1 may include an SSB index sent from the target satellite (eg, the second satellite SAT#2).

[0403] In the case where the GSCN is different, one or more indications #1 may include the frequency location (e.g., NR-ARFCN / E-UTRA-ARFCN) of the SSB transmitted from the target satellite (e.g., the second satellite SAT#2).

[0404] In the case where indication #1 includes DCI, indication #1 may include a bit indicating that the target satellite (e.g., the second satellite SAT #2) exists. In some embodiments, the DCI may include a 1-bit field to indicate that the target satellite (e.g., the second satellite SAT #2) exists. The DCI may be a DCI with or without DL allocation.

[0405] In some implementations, the DL BWP ID may indicate the first active DL BWP after satellite switching or after event #1 is satisfied.

[0406] In some implementations, the UL BWP ID may indicate the first active UL BWP after satellite switching or after event #1 is satisfied.

[0407] In some embodiments, the timestamp may indicate when the UE switches from a source satellite (e.g., a first satellite SAT#1) to a target satellite (e.g., a second satellite SAT#2). For example, the timestamp may indicate the time when the coverage area of ​​the serving cell provided by the target satellite (e.g., the second satellite SAT#2) begins to overlap the coverage area of ​​the serving cell provided by the source satellite (e.g., the first satellite SAT#1).

[0408] In some implementations, the timestamp may represent a time that is a multiple of 10 milliseconds after 00:00:00 on January 1, 1900 in the Gregorian calendar. The specific time may be between the time represented by the timestamp value minus 1 and the time represented by the timestamp value.

[0409] In some implementations, the timestamp may use a combination of super SFN, SFN, and / or subframe number to indicate time.

[0410] In some implementations, the duration of the first timer (eg, timer #1) may indicate an initial value of the first timer or a length of the first timer.

[0411] In some implementations, the first timer may be maintained by an RRC entity or a MAC entity.

[0412] In some implementations, the first timer may be in units of time slots, milliseconds, or subframes.

[0413] Reference again Figure 6 , in action 605, the UE may perform UE action #1 after receiving indication #1.

[0414] In some implementations, UE action #1 may include one or more of the following:

[0415] (1) When indication #1 includes a measurement configuration ID (e.g., MeasID), activate the indicated measurement configuration;

[0416] (2) calculating the TA value based on the common TA parameters and the ephemeris of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2);

[0417] (3) performing UL frequency synchronization according to satellite assistance information (e.g., NTN-Config) of a target satellite (e.g., a second satellite SAT#2) (e.g., satellite assistance information associated with a satellite ID indicated by preconfiguration or indication #1 or a neighboring NTN cell);

[0418] (4) Perform DL synchronization according to the SSB with the SSB index belonging to the target satellite (e.g., the second satellite SAT#2) (e.g., the GSCN may be the same);

[0419] (5) performing time and frequency synchronization with the target satellite (e.g., the second satellite SAT#2) according to the target satellite (e.g., the second satellite SAT#2) carried in the pre-configuration or the SSB information of gNB#2 (e.g., the time indicated by the timestamp carried in the pre-configuration);

[0420] (6) Switch to the target satellite (e.g., the second satellite SAT#2) at the time indicated by the timestamp carried in the preconfiguration;

[0421] (7) starting or restarting a first timer (e.g., timer #1) using an initial value provided in a preconfiguration or indicated in one or more indications #1, and decreasing the first timer over time;

[0422] (8) starting or restarting a first timer (e.g., timer #1) with a value of 0 and increasing the first timer over time; and / or

[0423] (9) When indication #1 is transmitted through the SIB and a certain bit or one or more fields in indication #1 indicates that a target satellite (e.g., the second satellite SAT#2) exists, L1 / L3 measurement is performed on the SSB transmitted by the target satellite (e.g., the second satellite SAT#2) or belonging to the target satellite (e.g., the second satellite SAT#2), where the SSB index of the SSB can be indicated in the SIB (e.g., SIB19, SIB2, SIB3, SIB4) or can be provided / configured in the pre-configuration.

[0424] In some implementations, the first timer may be started by an RRC entity of the UE.

[0425] In some implementations, the first timer may be started by a MAC entity of the UE.

[0426] In some embodiments, when there is only one MAC entity within the UE, the unique MAC entity can start the first timer.

[0427] In some embodiments, when there are two MAC entities within the UE, one of the two MAC entities associated with the MCG may start the first timer.

[0428] Reference again Figure 6 In action 606, the UE may transmit / send / report the measurement result / report of the service cell provided by the target satellite (e.g., the second satellite SAT#2) to the NW on the service cell provided by the source satellite (e.g., the first satellite SAT#1) (e.g., through the reporting configuration and the measurement configuration in the pre-configuration).

[0429] In some embodiments, the UE may be further configured to perform L1 or L3 measurements on a serving cell provided by a source satellite (eg, a first satellite SAT#1). The measurement signal may include an SSB received from the source satellite (eg, a first satellite SAT#1).

[0430] In some embodiments, the measurement result / report may be a result of an L1 measurement (eg, an L1 measurement result / report).

[0431] In some embodiments, the L1 measurement result / report may be a UCI. For example, the L1 measurement result / report may include a CSI report.

[0432] In some embodiments, the L1 measurement result / report may be transmitted on the PUCCH or PUSCH, depending on whether the measurement result / report is a periodic, semi-persistent or aperiodic CSI report.

[0433] In some embodiments, L1 measurement and / or L1 measurement result / report may be triggered / activated by indication #1, or triggered / activated upon successful reception of indication #1.

[0434] In some embodiments, when L1 measurement / CSI reporting is configured as "semi-persistent", L1 / measurement / CSI reporting can be activated by indication #1. In this case, UL grant (e.g., for reporting on PUSCH) or PUCCH resources (for reporting on PUCCH) can be indicated by indication #1.

[0435] In some embodiments, the transmission of L1 measurements / reports may be triggered by one or more events.

[0436] In some embodiments, the L1 measurement report may include a satellite ID and / or SSB-RSRP and / or SSBRI.

[0437] In some implementations, the measurement result / report may be a result of an L3 measurement. The L3 measurement may be configured by pre-configuration.

[0438] In some implementations, the report type of L3 measurement may be configured as a periodic measurement report.

[0439] In some implementations, the report type of L3 measurement may be configured as an event-triggered measurement report.

[0440] In some embodiments, the event may be one of the following: event A1, event A2, event A3, event A4, event A5, event A6, event D1, conditional event A3, conditional event A4, conditional event A5, conditional event D1, and / or conditional event T1. The above events are defined as follows.

[0441] Event A1: RSRP / RSRQ / SINR of the serving cell becomes better than an absolute threshold.

[0442] Event A2: RSRP / RSRQ / SINR of the serving cell becomes worse than an absolute threshold.

[0443] Event A3: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the RSRP / RSRQ / SINR offset of the PCell / PSCell.

[0444] Event A4: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the absolute threshold.

[0445] Event A5: RSRP / RSRQ / SINR of the PCell / PSCell becomes worse than a first absolute threshold, and RSRP / RSRQ / SINR of a neighboring cell / SCell becomes better than a second absolute threshold.

[0446] Event A6: The RSRP / RSRQ / SINR offset of the neighboring cell is better than that of the SCell.

[0447] Event D1: The distance between the UE and a reference location referenceLocation1 becomes (e.g., in meters or kilometers) greater than a configured threshold distanceThreshFromReference1 (e.g., also in meters or kilometers), and the distance between the UE and another reference location referenceLocation2 becomes less than another configured threshold distanceThreshFromReference2.

[0448] Conditional event A3: The RSRP / RSRQ / SINR offset of the conditional reconfiguration candidate is better than the RSRP / RSRQ / SINR of the PCell / PSCell.

[0449] Conditional event A4: RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than the absolute threshold.

[0450] Conditional event A5: the RSRP / RSRQ / SINR of the PCell / PSCell is worse than an absolute threshold 1 (absolutethreshold1), and the RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than another absolute threshold 2 (absolute threshold2).

[0451] Conditional event D1: The distance between the UE and a reference location referenceLocation1 of the conditional reconfiguration candidate becomes greater than a configured threshold distanceThreshFromReference1, and the distance between the UE and another reference location referenceLocation2 of the conditional reconfiguration candidate becomes less than another configured threshold distanceThreshFromReference2.

[0452] Conditional event T1: The time measured at the UE becomes greater than the configured threshold t1-Threshold but less than t1-Threshold+duration, where duration can be configured by the NW.

[0453] In some embodiments, the event may be an event different from the above event. In some embodiments, the event may be "RSRP / RSRQ / SINR of the target satellite becomes (offset) better than RSRP / RSRQ / SINR of the source satellite".

[0454] In some embodiments, the event may be "the RSRP / RSRQ of the SSB of the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2) becomes greater than the RSRP / RSRQ of the SSB of the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0455] In some embodiments, the report of the L3 measurement may include the RSRP of the SSB received from the target satellite (e.g., the second satellite SAT#2), as indicated by preconfiguration or indication #1.

[0456] In some implementations, the L3 measurement report may include RSRQ or SINR.

[0457] In some embodiments, the L3 measurement results / reports may include the RSRP and satellite ID of the SSB.

[0458] In some embodiments, the L3 measurement result / report may include the RSRP and indication of the SSB. When the indication exists and / or is configured to have a first value, it may indicate that the L3 measurement result / report is associated with a target satellite, which is indicated in the preconfiguration or indication #1. When the indication does not exist or is configured to have a second value, it may indicate that the L3 measurement result / report is not associated with the target satellite, which is indicated in the preconfiguration or indication #1.

[0459] Reference again Figure 6 In action 607, the UE may determine whether event #1 occurs in whole or in part; and in action 608, when event #1 occurs in whole or in part, the UE may perform UE action #2.

[0460] In some implementations, event #1 may include one or more of the following:

[0461] (1) The current time is the same as the timestamp provided in the preconfiguration or the time indicated by indication #1;

[0462] (2) The first timer (e.g., timer #1) expires;

[0463] (3) The value of the first timer (e.g., timer #1) reaches the value indicated by the duration of the first timer, where the duration of the timer may be provided in the preconfiguration or indicated by indication #1;

[0464] (4) An event that triggers an L3 measurement report of a target satellite (e.g., the second satellite SAT#2);

[0465] (5) an event that triggers an L1 measurement report of a target satellite (e.g., the second satellite SAT#2); and

[0466] (6) The RSRP / RSRQ of the SSB of the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2) becomes greater than the RSRP / RSRQ of the SSB of the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0467] In some implementations, UE action #2 may include one or more of the following:

[0468] (1) Apply the pre-configured beam indication (e.g., TCI state) to the next UL transmission and / or DL ​​reception;

[0469] (2) Apply the UL power control related information provided by the pre-configuration to the next UL transmission;

[0470] (3) Switch the active DL BWP according to the pre-configured DL BWP ID;

[0471] (4) Switching the active UL BWP according to the UL BWP ID provided by the pre-configuration;

[0472] (5) Re-acquire system information (e.g., SIB1 and / or other SIBs, such as SIB19), for example, regardless of whether the corresponding valueTag has been changed;

[0473] (6) Perform RACH-based actions: In case indication #1 and / or pre-configuration instructs the UE to perform the RA procedure, perform the RA procedure and transmit a preamble, where N_TA is equal to 0, the common TA is equal to the value calculated from the common TA parameters of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2), and the UE-specific TA is equal to the value calculated from the ephemeris of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2); and

[0474] (7) In case Indication #1 or pre-configuration indicates that the UE performs the RA procedure, it performs the RA procedure and transmits a preamble with N_TA equal to the value of Indication #1 or pre-configuration indication.

[0475] In some implementations, when a preamble index is provided by preconfiguration, the UE may use the provided preamble index for preamble transmission.

[0476] In some implementations, pre-configuration may provide time domain and / or frequency domain resources for PRACH transmission.

[0477] Reference again Figure 6 , after action 608, the UE may start to be served by the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2); in action 609, the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1) may stop providing service for the current coverage area through the source satellite (e.g., the first satellite SAT#1) and may switch to the next coverage area.

[0478] Figure 7 Shown is a signaling diagram of a satellite switching procedure initiated by a UE according to an exemplary embodiment of the present application.

[0479] refer to Figure 7 , shows a satellite handover process initiated by a UE with unchanged PCI in an NTN scenario. The satellite handover may be, for example, a soft or hard satellite handover. In some embodiments, Figure 7 Some of the "messages" shown in may optionally not exist. In some embodiments, Figure 7 The process shown in can include Figure 7 In some embodiments, Figure 7 The "message" represented by the solid arrow may include any message, such as SIB, pre-configuration settings, indication #1, L1 and / or L3 measurement results of the second (e.g., target) satellite SAT #2, and indication #3. In some embodiments, Figure 7 The “user data” represented by the double-dotted arrows may represent the transmission of UE data between entities connected by the double-dotted arrows.

[0480] refer to Figure 7 , in action 701, the UE may receive one or more SIBs broadcast by the NW.

[0481] In some embodiments, the received SIBs may include SIB19, SIB2, SIB3 and / or SIB4.

[0482] In some embodiments, the received SIB may include satellite assistance information of the serving satellite / NTN serving cell. The satellite assistance information may include one or more of NTN-Config, time information, reference position, distance threshold, one or more satellite identifications (IDs), and a list of neighboring NTN cells.

[0483] In some embodiments, NTN-Config may be an RRC IE. NTN-Config may be associated with the cell / gNB that broadcasts the SIB. NTN-Config may include one or more of the following:

[0484] (1) The ephemeris of the source satellite, provided by the high-level parameter ephemerisInfo;

[0485] (2) Public TA parameters of the source satellite, provided by the high-level parameter ta-Info;

[0486] (3) The validity period of the source satellite’s ephemeris and common TA parameters is provided by the higher-layer parameter ntn-UlSyncValidityDuration;

[0487] (4) The epoch time of the source satellite’s ephemeris and common TA parameters, provided by the higher-level parameter epochTime; and / or

[0488] (5) The cell-specific K_offset and K_mac are provided by the higher-level parameters cellSpecificKoffset and Kmac respectively.

[0489] In some implementations, the time information may indicate when a cell provided by the NTN semi-fixed system should stop providing service for the current coverage area provided by the t-Service.

[0490] In some embodiments, the reference position may include a reference position of a serving cell provided by an NTN quasi-terrestrial fixed system.The reference position may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0491] In some implementations, the distance threshold may indicate the distance between the UE and a serving cell reference location.The threshold may be used for location-based measurement initiation in RRC_IDLE and RRC_INACTIVE states.

[0492] In some embodiments, each satellite ID may indicate a set of satellite assistance information, or each satellite ID may be associated with a set of satellite assistance information. The satellite assistance information may be included in the NTN-Config.

[0493] In some embodiments, the neighboring NTN cell list may include NTN-Config IE and / or carrier frequency (eg, provided by higher layer parameter carrierFreq) and / or PCI (eg, provided by higher layer parameter physCellId) and / or satellite ID.

[0494] In some implementations, the number of neighboring cells in the list may be at most four.

[0495] In some implementations, the number of neighboring cells in the list may exceed four.

[0496] In some embodiments, the higher layer parameters of one or more neighboring cells may be set to the same value as the PCI of the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0497] In some embodiments, the physCellId of one or more neighboring cells may not be present, indicating that the PCI is the same as the NTN serving cell provided by the source satellite (eg, the first satellite SAT#1).

[0498] Reference again Figure 7 , in action 702, the UE may receive one or more pre-configurations from the NW.

[0499] In some implementations, the received pre-configuration may be carried in an RRC message, such as an RRCReconfiguration message.

[0500] In some implementations, the received pre-configuration may include one or more RRC parameters / IEs.

[0501] In some implementations, if the UE receives multiple pre-configurations, each pre-configuration may be associated with a different target satellite / target NTN cell.

[0502] In some embodiments, each pre-configuration may include one or more of the following: a first indication indicating a neighboring NTN cell, a satellite ID, satellite assistance information, an SSB index of multiple SSBs, time domain information about the SSB, one or more measurement configurations, one or more SMTC configurations, information about UL power control of PUSCH and / or PUCCH and / or SRS, ULBWP ID, DL BWP ID, a second indication indicating whether the UE performs a RA procedure, a third indication of an N_TA value; configuration including PRACH resources; a timestamp; a duration of a second timer; a fourth indication indicating an NTN serving cell / satellite; a duration of a prohibition timer; and / or parameters.

[0503] In some embodiments, the first indication may include an indication indicating to find a neighboring NTN cell from a neighboring NTN cell list included in the SIB via the target satellite (e.g., the second satellite SAT#2) (e.g., if the target satellite (NTN cell) is included in the neighboring NTN cell list in the SIB).

[0504] In some embodiments, the SIB may be SIB19, SIB2, SIB3, or SIB4.

[0505] In some embodiments, the first indication may be an integer indicating the order of entries in the neighboring NTN cell list contained in the SIB. For example, if the first indication is "1", the satellite assistance information (e.g., NTN-Config) of the target satellite (e.g., the second satellite SAT#2) may be the NTN-Config of the first neighboring NTN cell in the list; if the indication is "2", the satellite assistance information (e.g., NTN-Config) of the target satellite may be the NTN-Config of the second neighboring NTN cell in the list; and so on.

[0506] In some implementations, the UE may use satellite assistance information associated with a satellite ID included in a pre-configuration (eg, NTN-Config) during a satellite switching process.

[0507] In some embodiments, the satellite assistance information included in the pre-configuration may include satellite assistance information of the NTN serving cell provided by a target satellite (eg, the second satellite SAT#2).

[0508] In some embodiments, the satellite assistance information included in the pre-configuration may include one or more of the following:

[0509] (1) NTN-Config RRC IE of the target satellite (e.g., the second satellite SAT#2);

[0510] (2) Satellite ID of the target satellite (e.g., the second satellite SAT#2);

[0511] (3) Time information indicating when a cell provided by the NTN quasi-fixed system should stop serving its current coverage area provided by the t-Service;

[0512] (4) The reference position of the serving cell provided by the NTN quasi-geo-fixed system. The reference position can be used to initiate location-based measurements in the RRC_IDLE and RRC_INACTIVE states; and / or

[0513] (5) Distance threshold, indicating the distance between the UE and the reference location of the serving cell. This threshold can be used to start location-based measurements in the RRC_IDLE and RRC_INACTIVE states.

[0514] In some implementations, the SSB index included in the preconfiguration may be the SSB index of the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0515] In some implementations, the SSB index of the SSB transmitted by the target satellite (eg, the second satellite SAT#2) may be represented by a bitmap.

[0516] In some embodiments, the size (number of bits) of the bitmap may be the maximum number of SSBs per half-frame (eg, 4, 8, or 64).

[0517] In some implementations, the bitmap may indicate the time domain location of the SSBs transmitted by the target satellite (eg, the second satellite SAT#2) in a half-frame.

[0518] In some implementations, the first / leftmost bit of such a bitmap may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0519] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB has not been transmitted, while a 1 value may indicate that the corresponding SSB has been transmitted.

[0520] In some implementations, the size (eg, number of bits) of the bitmap may be 8 bits.

[0521] In some embodiments, when the maximum number of SSBs per half frame is 4, only the leftmost 4 bits in the bitmap may be valid, and the UE may ignore the rightmost 4 bits in the bitmap.

[0522] In some embodiments, when the maximum number of SSBs per half-frame is 8, all 8 bits in the bitmap may be valid.

[0523] In some implementations, the first / leftmost bit may correspond to SSB index 0, the second bit may correspond to SSB index 1, and so on.

[0524] In some embodiments, when the maximum number of SSBs per half-frame is 64, all 8 bits in the bitmap may be valid.

[0525] In some embodiments, the first / leftmost bit can correspond to the first SSB index in each group (e.g., SSB index 0, 8, etc.); the second bit can correspond to the second SSB index in each group (e.g., SSB index 1, 9, etc.), and so on. Each SSB group can be determined as follows: Group #1 can include SSB indices from 0 to 7, Group #2 can include SSB indices from 8 to 15, and so on.

[0526] In some implementations, a 0 value in the bitmap may indicate that the corresponding SSB is not transmitted, while a 1 value may indicate that the corresponding SSB is transmitted.

[0527] In some embodiments, if the NW indicates (e.g., through the RRC parameter ssb-PositionsInBurst) that the SSB index transmitted from the NTN serving cell (e.g., through the source satellite (e.g., the first satellite SAT#1)) is also indicated by the NW through the bitmap as being transmitted from the target satellite (e.g., the second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the target satellite (e.g., the second satellite SAT#2). In this case, the bitmap may override the RRC parameter ssb-PositionsInBurst when both indicate transmission of an SSB with a specific index.

[0528] In some embodiments, if the NW (e.g., through the RRC parameter ssb-PositionsInBurst) indicates through a bitmap that an SSB index transmitted from an NTN serving cell (e.g., through a source satellite (e.g., a first satellite SAT#1)) is also indicated by the NW to be transmitted from a target satellite (e.g., a second satellite SAT#2), the UE may assume that the corresponding SSB is transmitted from the NTN serving cell provided by the source satellite (e.g., the first satellite SAT#1). In this case, the RRC parameter ssb-PositionsInBurst may override the bitmap when both indicate transmission of an SSB with a specific index.

[0529] In some embodiments, the UE may assume that the bitmap and the RRC parameter ssb-PositionsInBurst do not simultaneously indicate a value of 1 for the same SSB index (eg, an SSB is transmitted).

[0530] In some implementations, the time domain information included in the preconfiguration may be time domain information about the SSB transmitted from the target satellite (eg, the second satellite SAT#2).

[0531] In some embodiments, the UE may assume that the SSB received during the duration indicated by the time domain information is transmitted from the target satellite (e.g., the second satellite SAT#2). When the UE is required / configured to measure the SSB of the target satellite (e.g., the second satellite SAT#2), the UE may measure the SSB received during the duration indicated by the time domain information.

[0532] In some implementations, the time domain information may be one or a combination of the following:

[0533] (1) One or more super SFNs;

[0534] (2) one or more SFNs;

[0535] (3) one or more subframe numbers;

[0536] (4) one or more time slot numbers; and

[0537] (5) One or more SSB indexes.

[0538] In some embodiments, each of the one or more measurement configurations may include one or more measurement objects, which may include the time / frequency location and SCS of the SSB of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2).

[0539] In some implementations, the one or more measurement configurations may include one or more SMTC configurations.The UE may perform measurements on SSBs received from a target satellite (eg, a second satellite SAT#2) during the SMTC window.

[0540] In some implementations, the one or more measurement configurations may include one or more CSI reporting configurations.

[0541] In some implementations, CSI reporting may be configured as periodic, semi-persistent on PUCCH, semi-persistent on PUSCH, or aperiodic.

[0542] In some embodiments, the reporting quantity configuration of the CSI report can be configured as "ssb-Index-RSRP", which may mean that the UE can report the reference signal received power (RSRP) of the CSI measurement through one or more SSB indices.

[0543] In some embodiments, one or more SMTC configurations included in the pre-configuration may be used for measurements on the SSB of the NTN serving cell provided by the target satellite (eg, the second satellite SAT#2).

[0544] In some embodiments, UL power control of PUSCH and / or PUCCH and / or SRS may include one or more of the following:

[0545] (1) one or more p0-alpha sets (ID);

[0546] (2) Path loss reference signal (PL-RS) ID, such as pathlossReferenceIndex, which may indicate a reference signal that the UE may use to estimate path loss and calculate UL transmission power;

[0547] (3) Nominal PUSCH power configuration, e.g., preambleReceivedTargetPower, p0-NominalWithoutGrant, p0-NominalWithGrant, p0-PUCCH-Value, which may be used by the UE to calculate the UL transmit power; and / or

[0548] (4) Index of the PUSCH power control adjustment state, which can be used by the UE to perform closed-loop power control and calculate the UL transmit power.

[0549] In some implementations, the UL BWP ID may indicate the first active BWP ID after satellite switching or after event #1 is satisfied.

[0550] In some implementations, the UL BWP ID may indicate the first active BWP ID after satellite switching or after event #1 is satisfied.

[0551] In some implementations, the second indication may be an indication of whether the UE can perform the RA procedure when event #1 is satisfied, ENUMERATED is set to "{enabled}" or ENUMERATED is set to "{enabled, disabled}".

[0552] In some implementations, the third indication may be an indication of an N_TA value that the UE may use to determine the transmission time of the preamble as part of the RA procedure when event #1 is met.

[0553] In some implementations, the third indication may instruct the UE to use an N_TA value equal to 0 or to use an N_TA value equal to a currently stored N_TA value.

[0554] In some implementations, the third indication may provide a specific N_TA value to the UE.

[0555] In some implementations, the configuration including the PRACH resources may include a preamble index and / or dedicated time domain and / or frequency domain PRACH resources.

[0556] In some embodiments, the timestamp may indicate the time when the UE switches from the source satellite (e.g., the first satellite SAT#1) to the target satellite (e.g., the second satellite SAT#2). For example, the timestamp may indicate the time when the coverage area of ​​the service cell provided by the target satellite (e.g., the second satellite SAT#2) begins to overlap the coverage area of ​​the service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0557] In some implementations, the timestamp may indicate a time that is a multiple of 10 milliseconds after 00:00:00 (Gregorian calendar) January 1, 1900. The exact switching time may be between the time indicated by the value of the timestamp minus 1 and the time indicated by the value of the timestamp.

[0558] In some implementations, the timestamp may use a combination of super SFN, SFN, and / or subframe number to indicate time.

[0559] In some implementations, the duration of the second timer (eg, represented as Timer #2) may indicate an initial value of the second timer or a length of the second timer.

[0560] In some implementations, the second timer may be a timer maintained by an RRC entity or a MAC entity.

[0561] In some implementations, the unit of duration may be a time slot, a radio frame, a second, a millisecond, or a subframe.

[0562] In some implementations, the fourth indication included in the pre-configuration may be an indication of an NTN serving cell / satellite to which the UE may transmit indication #3.

[0563] In some implementations, the fourth indication may be ENUMBERATED set to {first value, second value}.

[0564] In some embodiments, the first value of the fourth indication may indicate that the UE transmits the indication #3 to the source satellite (e.g., the first satellite SAT#1) (e.g., via the NTN service cell provided thereby). In some embodiments, the second value of the fourth indication may indicate that the UE transmits the indication #3 to the target satellite (e.g., the second satellite SAT#2) (e.g., via the NTN service cell provided thereby). In some embodiments, when the fourth indication is not provided, the UE may transmit the indication #3 to the source satellite (e.g., the first satellite SAT#1) (e.g., via the NTN service cell provided thereby). In some embodiments, when the fourth indication is not provided, the UE may transmit the indication #3 to the target satellite (e.g., the second satellite SAT#2) (e.g., via the NTN service cell provided thereby).

[0565] In some implementations, the fourth indication may be ENUMERATED set to {first value}.

[0566] In some embodiments, the first value of the fourth indication may indicate that the UE transmits indication #3 to the source satellite (e.g., the first satellite SAT#1) (e.g., via the provided NTN serving cell). In some embodiments, the first value of the fourth indication may indicate that the UE transmits indication #3 to the target satellite (e.g., the second satellite SAT#2) (e.g., via the provided NTN serving cell). In some embodiments, when the fourth indication is not provided, the UE may transmit indication #3 to the source satellite (e.g., the first satellite SAT#1) (e.g., via the provided NTN serving cell). In some embodiments, when the fourth indication is not provided, the UE may transmit indication #3 to the target satellite (e.g., the second satellite SAT#2) (e.g., via the provided NTN serving cell).

[0567] In some implementations, the pre-configuration may include the duration of a timer for inhibiting retransmission indication #3.

[0568] In some embodiments, the pre-configuration may include a parameter indicating the number of times the UE may (re)transmit indication #3 to the NW (eg, once, twice, three times, etc.) This parameter may be an integer or of type ENUMERATED.

[0569] Reference again Figure 7 In action 703, the coverage area of ​​the service cell provided by the target satellite (eg, the second satellite SAT#2) may begin to overlap the coverage area of ​​the service cell provided by the source satellite (eg, the first satellite SAT#1).

[0570] In action 704, the UE may receive one or more indications #1 from the NW.

[0571] In some embodiments, one or more indications #1 may indicate that the NTN service cell provided by the target satellite (eg, the second satellite SAT#2) begins to cover the coverage area of ​​the service cell provided by the source satellite (eg, the first satellite SAT#1).

[0572] In some implementations, one or more indications #1 may be transmitted via a source satellite (eg, a first satellite SAT#1).

[0573] In some implementations, one of the one or more indications #1 may be a MAC CE.

[0574] In some implementations, the UE may send a HARQ ACK information bit in response to a decoding result (eg, indication #1) of a PDSCH carrying a MAC CE.

[0575] In some implementations, one of the one or more indications #1 may be a group-common DCI.The group-common DCI may be a DCI with a CRC scrambled by a group-common RNTI (eg, G-RNTI) or a RNTI corresponding to the NTN.

[0576] In some implementations, one of the one or more indications #1 may be a UE-specific DCI with a CRC scrambled by a UE-specific RNTI, such as a C-RNTI, CS-RNTI, or MCS-RNTI.

[0577] In some implementations, the DCI may schedule the PDSCH.The UE may send the HARQ-ACK information bits in response to receiving the PDSCH in a time slot indicated by a field contained in the DCI (eg, the PDSCH-to-HARQ_feedback timing indicator field).

[0578] In some implementations, in the event that the UE sends a NACK to the NW in response to a scheduled PDSCH reception, the UE may apply the information indicated by indication #1.

[0579] In some implementations, the UE may apply the information indicated by indication #1 regardless of whether the UE sends an ACK or a NACK to the NW in response to the scheduled PDSCH reception.

[0580] In some embodiments, the DCI may be a DCI without DL allocation. In other words, the DCI may not schedule PDSCH reception. In some embodiments, the NW may set one or more fields contained in the DCI to a specific value. In some embodiments, the NW may use a specific RNTI (e.g., C-RNTI, CS-RNTI, MCS-RNTI or other RNTI) to scramble the CRC of the DCI. If the UE detects that one or more fields contained in the DCI are set to a specific value and / or if the UE finds that the CRC of the DCI is scrambled by a specific RNTI, the UE can recognize that the DCI does not schedule any PDSCH reception.

[0581] In some embodiments, if the UE sends HARQ information to the NW in response to DCI reception, the UE may apply the information indicated by indication #1. It should be noted that the HARQ information may be ACK-only, NACK-only, or ACK / NACK information. ACK-only means that the UE only sends ACK. NACK-only means that the UE only sends NACK. ACK / NACK means that the UE may send either ACK or NACK.

[0582] In some implementations, regardless of whether the UE sends ACK or NACK to the NW in response to DCI reception, the UE may apply the information indicated by indication #1.

[0583] In some embodiments, the DCI may include a field to indicate which pre-configuration the UE should apply. This field may indicate a satellite ID or an indication of a neighboring NTN cell.

[0584] In some embodiments, one of the one or more indications #1 may be a SIB or a part of a SIB.

[0585] In some embodiments, the SIB may be SIB19, SIB1, SIB2, SIB3, or SIB4.

[0586] In some implementations, the NW may request the UE to re-acquire the SIB.

[0587] In some embodiments, if indication #1 exists in the SIB, the UE in the RRC_IDLE state can perform initial access and / or initiate an RRC connection procedure and / or RA procedure using information of the target satellite (e.g., the second satellite SAT#2) indicated by indication #1.

[0588] In some embodiments, the UE may use the satellite assistance information indicated in indication #1 to perform DL synchronization and UL transmission. Specifically, the UE may use the public TA parameters and ephemeris of the target satellite (e.g., the second satellite SAT#2) to determine the TA value when performing UL transmission during the RA process.

[0589] In some implementations, the UE may use the SSB of the SSB index indicated by indication #1 to determine the transmission occasion (eg, PRACH occasion) of the RA preamble during the RA procedure.

[0590] In some embodiments, one or more indications #1 may include one or more of the following: a measurement object ID, an indication of a neighboring NTN cell via a target satellite, an SSB index, a frequency position, a bit indicating the presence of a target satellite, a DLBWP ID, a UL BWP ID, a timestamp; a duration of a second timer (e.g., denoted as timer #2); and a parameter indicating the number of times the UE can (re)transmit indication #3 to the NW.

[0591] In some implementations, the measurement object ID may indicate that the measurement object is configured in the pre-configuration.

[0592] In some embodiments, the indication may indicate a neighboring NTN cell via a target satellite (eg, the second satellite SAT#2) from a neighboring NTN cell list included in SIB19.

[0593] In the case where the GSCN is the same, one or more indications #1 may include an SSB index sent from the target satellite (eg, the second satellite SAT#2).

[0594] In the case where the GSCN is different, one or more indications #1 may include the frequency location (e.g., NR-ARFCN / E-UTRA-ARFCN) of the SSB transmitted from the target satellite (e.g., the second satellite SAT#2).

[0595] In the case where indication #1 includes DCI, indication #1 may include a bit indicating that the target satellite (e.g., the second satellite SAT #2) exists. In some embodiments, the DCI may include a 1-bit field to indicate that the target satellite (e.g., the second satellite SAT #2) exists. The DCI may be a DCI with or without DL allocation.

[0596] In some embodiments, the DL BWP ID may indicate the first active DL BWP after a satellite switch or successful reception of one or more indications #4s.

[0597] In some embodiments, the UL BWP ID may indicate the first active UL BWP after a satellite switch or successful reception of one or more indications #4s.

[0598] In some embodiments, the timestamp may indicate when the UE switches from a source satellite (e.g., a first satellite SAT#1) to a target satellite (e.g., a second satellite SAT#2). For example, the timestamp may indicate the time when the coverage area of ​​the serving cell provided by the target satellite (e.g., the second satellite SAT#2) begins to overlap the coverage area of ​​the serving cell provided by the source satellite (e.g., the first satellite SAT#1).

[0599] In some implementations, the timestamp may represent a time that is a multiple of 10 milliseconds after 00:00:00 on January 1, 1900 in the Gregorian calendar. The specific time may be between the time represented by the timestamp value minus 1 and the time represented by the timestamp value.

[0600] In some implementations, the timestamp may use a combination of super SFN, SFN, and / or subframe number to indicate time.

[0601] In some implementations, the duration of the second timer (eg, represented as Timer #2) may indicate an initial value of the second timer or a length of the second timer.

[0602] In some implementations, the second timer may be a timer maintained by an RRC entity or a MAC entity.

[0603] In some implementations, the second timer may be in units of time slots, milliseconds, or subframes.

[0604] In some embodiments, one or more indications #1 may include a parameter indicating how many times the UE may (re)transmit indication #3 to the NW (eg, once, twice, three times, etc.). The parameter may be an integer or an ENUMERATED type.

[0605] Reference again Figure 7 , in action 705, the UE may perform UE action #1 (eg, upon successful reception of indication #1).

[0606] In some implementations, UE action #1 may include one or more of the following:

[0607] (1) When indication #1 includes a measurement configuration ID (e.g., MeasID), activate the indicated measurement configuration;

[0608] (2) calculating the TA value according to the common TA parameters and the ephemeris of the NTN serving cell provided by the target satellite (e.g., the second satellite SAT#2);

[0609] (3) performing UL frequency synchronization according to satellite assistance information (e.g., NTN-Config) of a target satellite (e.g., a second satellite SAT#2) (e.g., satellite assistance information associated with a satellite ID indicated by preconfiguration or indication #1 or a neighboring NTN cell);

[0610] (4) performing DL synchronization (e.g., a DL synchronization procedure) according to an SSB with an SSB index belonging to a target satellite (e.g., a second satellite SAT#2) (e.g., the GSCN may be the same); and / or

[0611] (5) performing time and frequency synchronization with the target satellite (e.g., the second satellite SAT#2) according to the SSB information of the target satellite (e.g., the second satellite SAT#2) or gNB#2 carried in the pre-configuration (e.g., the time indicated by the timestamp carried in the pre-configuration); and / or

[0612] (6) When indication #1 is transmitted through SIB, and a certain bit or one or more fields in indication #1 indicates that the target satellite (e.g., the second satellite SAT#2) exists, L1 / L3 measurement is performed on the SSB transmitted by the target satellite (e.g., the second satellite SAT#2) or belonging to the target satellite (e.g., the second satellite SAT#2), where the SSB index of the SSB can be indicated in the SIB (e.g., SIB19, SIB2, SIB3, SIB4) or can be provided / configured in the pre-configuration.

[0613] Reference again Figure 7 In action 706, the UE may transmit / send / report the measurement result / report of the service cell provided by the target satellite (e.g., the second satellite SAT#2) to the NW on the service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0614] In some embodiments, the UE may be further configured to perform L1 or L3 measurements on a serving cell provided by a source satellite (eg, the first satellite SAT#1). The measurement signal may include an SSB received from the source satellite (eg, the first satellite SAT#1).

[0615] In some embodiments, the measurement result / report may be a result of an L1 measurement (eg, an L1 measurement result / report).

[0616] In some embodiments, the L1 measurement result / report may be a UCI. For example, the L1 measurement result / report may include a CSI report.

[0617] In some implementations, the L1 measurement results / reports may be transmitted on the PUCCH or PUSCH, depending on whether the measurement results / reports are periodic, semi-persistent or aperiodic CSI reports.

[0618] In some embodiments, L1 measurement and / or L1 measurement result / report may be triggered / activated by indication #1, or triggered / activated upon successful reception of indication #1.

[0619] In some embodiments, when L1 measurement / CSI reporting is configured as "semi-persistent", L1 / measurement / CSI reporting can be activated by indication #1. In this case, UL grant (e.g., for reporting on PUSCH) or PUCCH resources (for reporting on PUCCH) can be indicated by indication #1.

[0620] In some embodiments, the transmission of L1 measurements / reports may be triggered by one or more events.

[0621] In some embodiments, the L1 measurement report may include a satellite ID and / or SSB-RSRP and / or SSBRI.

[0622] In some embodiments, the measurement result / report may be a result of an N L3 measurement. The L3 measurement may be configured by pre-configuration.

[0623] In some implementations, the report type of L3 measurement may be configured as a periodic measurement report.

[0624] In some implementations, the report type of L3 measurement may be configured as an event-triggered measurement report.

[0625] In some embodiments, the event may be one of the following: event A1, event A2, event A3, event A4, event A5, event A6, event D1, conditional event A3, conditional event A4, conditional event A5, conditional event D1, and / or conditional event T1. The above events are defined as follows.

[0626] Event A1: RSRP / RSRQ / SINR of the serving cell becomes better than an absolute threshold.

[0627] Event A2: RSRP / RSRQ / SINR of the serving cell becomes worse than an absolute threshold.

[0628] Event A3: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the RSRP / RSRQ / SINR offset of the PCell / PSCell.

[0629] Event A4: The RSRP / RSRQ / SINR of the neighboring cell becomes better than the absolute threshold.

[0630] Event A5: RSRP / RSRQ / SINR of the PCell / PSCell becomes worse than a first absolute threshold, and RSRP / RSRQ / SINR of a neighboring cell / SCell becomes better than a second absolute threshold.

[0631] Event A6: The RSRP / RSRQ / SINR offset of the neighboring cell is better than that of the SCell.

[0632] Event D1: The distance between the UE and a reference location referenceLocation1 becomes (e.g., in meters or kilometers) greater than a configured threshold distanceThreshFromReference1 (e.g., also in meters or kilometers), and the distance between the UE and another reference location referenceLocation2 becomes less than another configured threshold distanceThreshFromReference2.

[0633] Conditional event A3: The RSRP / RSRQ / SINR offset of the conditional reconfiguration candidate is better than the RSRP / RSRQ / SINR of the PCell / PSCell.

[0634] Conditional event A4: RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than the absolute threshold.

[0635] Conditional event A5: the RSRP / RSRQ / SINR of the PCell / PSCell is worse than an absolute threshold 1 (absolutethreshold1), and the RSRP / RSRQ / SINR of the conditional reconfiguration candidate is better than another absolute threshold 2 (absolute threshold2).

[0636] Conditional event D1: The distance between the UE and a reference location referenceLocation1 of the conditional reconfiguration candidate becomes greater than a configured threshold distanceThreshFromReference1, and the distance between the UE and another reference location referenceLocation2 of the conditional reconfiguration candidate becomes less than another configured threshold distanceThreshFromReference2.

[0637] Conditional event T1: The time measured at the UE becomes greater than the configured threshold t1-Threshold but less than t1-Threshold+duration, where duration can be configured by the NW.

[0638] In some embodiments, the event may be an event different from the above event. In some embodiments, the event may be "RSRP / RSRQ / SINR of the target satellite becomes (offset) better than RSRP / RSRQ / SINR of the source satellite".

[0639] In some embodiments, the event may be "the RSRP / RSRQ of the SSB of the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2) becomes greater than the RSRP / RSRQ of the SSB of the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1)".

[0640] In some embodiments, the report of the L3 measurement may include the RSRP of the SSB received from the target satellite (e.g., the second satellite SAT#2), as indicated by preconfiguration or indication #1.

[0641] In some implementations, the L3 measurement report may include RSRQ or SINR.

[0642] In some embodiments, the L3 measurement results / reports may include the RSRP and satellite ID of the SSB.

[0643] In some embodiments, the L3 measurement result / report may include the RSRP and indication of the SSB. When the indication is present and / or configured to have a first value, it may indicate that the L3 measurement result / report is associated with the target satellite, which is indicated in the preconfiguration or indication #1. When the indication is absent or configured to have a second value, it may indicate that the L3 measurement result / report is not associated with the target satellite, which is indicated in the preconfiguration or indication #1.

[0644] Reference again Figure 7 , in action 707, the UE may determine whether a specific condition (e.g., represented as condition #1) is met; and in action 708, the UE may transmit an indication #3 to the NW to notify the NW that the UE has determined to switch from the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1) to the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2) when the specific condition is met.

[0645] In some embodiments, a specific condition (e.g., condition #1) may include one or more of the following:

[0646] (1) The current time is the same as the timestamp provided in the preconfiguration or indicated by indication #1;

[0647] (2) the value of the first timer (e.g., timer #1) reaches the duration of the first timer preconfigured or indicated by indication #1;

[0648] (3) An event triggering an L3 measurement report of a target satellite (e.g., the second satellite SAT#2) occurs;

[0649] (4) an event that triggers an L1 measurement report of a target satellite (e.g., the second satellite SAT#2) occurs; and

[0650] (5) The RSRP / RSRQ of the SSB of the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2) becomes greater than the RSRP / RSRQ of the SSB of the NTN service cell provided by the source satellite (e.g., the first satellite SAT#1).

[0651] In some embodiments, the UE may transmit indication #3 to the NW via the NTN serving cell provided by the source satellite (eg, the first satellite SAT #1) (eg, as configured in pre-configuration or indicated by indication #1).

[0652] In some implementations, the UE may transmit indication #3 to the NW via the NTN serving cell provided by the target satellite (eg, the second satellite SAT #2) (as configured in pre-configuration or indicated by indication #1).

[0653] In some implementations, indication #3 may be a MAC CE. In some implementations, the UE may transmit indication #3 using pre-allocated PUSCH resources.

[0654] In some implementations, the pre-allocated PUSCH resources may be scheduled by a UL grant of a type 1 configuration or a UL grant of a type 2 configuration.

[0655] In some implementations, indication #3 may be UCI. In some implementations, the UE may transmit indication #3 using a PUCCH resource configured by the NW, wherein the PUCCH resource is specifically configured for indication #3.

[0656] In some embodiments, indication #3 (e.g., UCI) may be a new type of UCI that is different from HARQ-ACK information bits, scheduling request (SR) information bits, CSI bits, link radio (LRR) information, and unused configured grant (CG) PUSCH transmission occasion indication bits.

[0657] In some implementations, the UE cannot multiplex other (types of) UCI ​​with indication #3 in the same PUCCH resource.

[0658] In some implementations, the UE may not wish to be configured by the NW to multiplex indication #3 with other (types of) UCI ​​in the same PUCCH resource.

[0659] In some embodiments, when dedicated PUCCH resources overlap with PUSCH scheduled by DCI or overlap with PUSCH scheduled by UL grant configured by type 1 or UL grant configured by type 2, the UE may not expect to transmit more than two UCI bits in the PUCCH and / or the UE may multiplex the UCI bits transmitted in the PUCCH into the PUSCH.

[0660] Reference again Figure 7 , in action 709, the UE may start or restart a second timer (eg, timer #2).

[0661] In some implementations, the UE may start or restart a second timer (eg, timer #2) using an initial value provided in the preconfiguration or indicated in one or more indications #1, and decrease the second timer over time.

[0662] In some implementations, the UE may start or restart the second timer (eg, timer #2) with a value of 0, and increase the second timer over time.

[0663] In some implementations, the RRC entity of the UE may start a second timer.

[0664] In some implementations, the MAC entity of the UE may start a second timer.

[0665] In some embodiments, when there is only one MAC entity within the UE, the only MAC entity may start the second timer.

[0666] In some embodiments, when there are two MAC entities in the UE, one of the two MAC entities associated with the MCG may start a second timer.

[0667] In some implementations, the UE may set a counter (eg, denoted as counter #1) to zero (eg, reset counter #1). Counter #1 may be used to count the number of times indication #3 has been (re)transmitted.

[0668] Reference again Figure 7 In action 710, the UE may receive an indication #4 from the NW while the second timer (e.g., timer #2) is running to determine whether the UE is allowed to perform UE action #2. For example, indication #4 may be used to determine whether the UE is allowed to switch from an NTN service cell provided by a source satellite (e.g., a first satellite SAT #1) to an NTN service cell provided by a target satellite (e.g., a second satellite SAT #2) (e.g., requested by indication #3), or the UE may retransmit indication #3.

[0669] In some implementations, indication #4 may be a MAC CE.

[0670] In some implementations, indication #4 may be a DCI. In some implementations, the DCI may be a DCI format 1_0, a DCI format 1_1, a DCI format 0_0, a DCI format 0_1, or another DCI format.

[0671] In some embodiments, the UE may receive indication #4 from the NW via a source satellite (eg, a first satellite SAT#1) or via a target satellite (eg, a second satellite SAT#2).

[0672] In some implementations, the UE may receive indication #4 from the NW via the satellite through which indication #3 was sent.

[0673] In some embodiments, indication #4 may include one or more of an indication field, a beam indication, information about UL power control, a DL BWP ID, a UL BWP ID, an indication of whether the UE can perform a RA procedure, an indication of an N_TA value, and a preamble index.

[0674] In some implementations, the indication field included in indication #4 may indicate an acknowledgement from the NW in response to indication #3.

[0675] In some embodiments, the indication field may be 1 bit, which may be set to "1" or "0". In some embodiments, the first value of the bit (e.g., "1") may mean that the NW allows the UE to perform UE action #2 (e.g., serving satellite switching). In some embodiments, the second value of the bit (e.g., "0") may mean that the NW does not allow the UE to perform UE action #2 (e.g., serving satellite switching).

[0676] In some embodiments, the beam indication included in indication #4 may be a beam indication of a specific channel and / or a specific reference signal (eg, TCI status).

[0677] In some embodiments, the information about UL power control of PUSCH and / or PUCCH and / or SRS may include one or more of the following:

[0678] (1) one or more p0-alpha sets (ID);

[0679] (2) PL-R ID, e.g., pathlossReferenceIndex, which may indicate a reference signal that the UE may use to estimate path loss and calculate UL transmission power;

[0680] (3) Nominal PUSCH power configuration, such as preambleReceivedTargetPower, p0-NominalWithoutGrant, p0-NominalWithGrant, p0-PUCCH-Value, which can be used by the UE to calculate the UL transmit power;

[0681] (4) Index of the PUSCH power control adjustment state, which can be used by the UE to perform closed-loop power control and calculate the UL transmit power.

[0682] In some embodiments, the DL BWP ID may indicate the first active DL BWP after a satellite switch or after successful reception of one or more indications #2.

[0683] In some embodiments, the UL BWP ID may indicate the first active UL BWP after a satellite switch or after successful reception of one or more indications #2.

[0684] In some implementations, indication #4 may include an indication of whether the UE can perform a RA procedure after receiving indication #2 (eg, a handover command), setting ENUMERATED to {Enable}, or setting ENUMERATED to {Enable, Disable}.

[0685] In some implementations, indication #4 may include an indication of an N_TA value that the UE may use to determine the transmission time of a preamble that is part of the RA procedure following receipt of indication #2.

[0686] In some implementations, the indication of the N_TA value may instruct the UE to use an N_TA value equal to 0 or to use an N_TA value equal to a currently stored N_TA value.

[0687] In some implementations, when the UE receives indication #4 from the NW, the UE may stop the second timer (eg, timer #2).

[0688] In some implementations, when the UE has received indication #4 (eg, before the second timer expires) and the indication field included in indication #4 indicates a first value (eg, "1"), the UE may perform UE action #2.

[0689] In some embodiments, when the second timer expires, if the UE has not received indication #4 from the NW, or if the UE has received indication #4 and the indication field included in indication #4 indicates a second value (e.g., “0”), the UE may not perform UE action #2 (e.g., Figure 7), and / or the UE may retransmit indication #3 immediately or retransmit indication #3 at the next transmission occasion of indication #3. In addition, the UE may increase counter #1 by 1.

[0690] In some embodiments, when the second timer expires, if the UE has not received indication #4 from the NW, or if the UE has received indication #4 and the indication field included in indication #4 indicates a second value (e.g., “0”): the UE may not perform UE action #2 (e.g., Figure 7 and / or if the duration of the prohibit timer is provided by pre-configuration or the duration of the prohibit timer is not 0, the UE may start or restart the prohibit timer to retransmit indication #3, with its initial value set to the duration provided by the pre-configuration.

[0691] In some embodiments, the UE may not (re)transmit indication #3 to the NW while the inhibit timer is running.

[0692] In some implementations, when the inhibit timer expires, the UE may (re)transmit indication #3 to the NW (eg, at the next transmission occasion of indication #3). In addition, the UE may increase counter #1 by 1.

[0693] In some embodiments, the number of times the UE may (re)transmit indication #3 to the NW (eg, the maximum number of (re)transmissions of indication #3) may be configured by the NW in a pre-configuration or in indication #1.

[0694] In some embodiments, in case Counter #1 is equal to a parameter indicating a maximum number of (re)transmissions of Indication #3 (eg, as provided in pre-configuration or indicated by Indication #1), the UE may not retransmit Indication #3.

[0695] In some implementations, UE action #2 may include one or more of the following:

[0696] (1) Apply the beam indication (e.g., TCI state) indicated / provided by indication #1 or pre-configuration to subsequent UL transmission and / or DL ​​reception;

[0697] (2) Apply the UL power control information indicated / provided by indication #1 or pre-configuration to subsequent UL transmissions;

[0698] (3) Switch the active DL BWP to the DL BWP ID indicated by indication #1 / preconfiguration / indication #4;

[0699] (4) Switch the active UL BWP to the UL BWP ID indicated by indication #1 / pre-configured indication #4;

[0700] (5) Re-acquire system information (e.g., SIB1 and / or other SIBs, such as SIB2, SIB3, SIB4, SIB19, etc.), regardless of whether the corresponding valueTag has been changed;

[0701] (6) Performing RACH-based actions: In the case where indication #1, indication #2 and / or pre-configuration indicates that the UE performs (e.g., 2-step / 4-step) an RA procedure, performing an RA procedure and transmitting a preamble, where N_TA is equal to 0, the common TA is equal to a value calculated from the common TA parameters of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2), and the UE-specific TA is equal to a value calculated from the ephemeris of the NTN serving cell of the target satellite (e.g., the second satellite SAT#2); and / or

[0702] (7) In case Indication #1 or pre-configuration indicates that the UE performs the RA procedure, it performs the RA procedure and transmits a preamble with N_TA equal to the value of Indication #1 or pre-configuration indication.

[0703] In some implementations, when preconfiguration / indication #4 provides a preamble index, the UE may use the provided / indicated preamble index for preamble transmission.

[0704] In some implementations, pre-configuration may provide time domain and / or frequency domain resources for PRACH transmission.

[0705] Reference again Figure 7 In action 711, when the UE performs UE action #2, the UE may start to be served by the NTN service cell provided by the target satellite (e.g., the second satellite SAT#2); in action 712, the NTN service cell may stop providing service for the current coverage area through the source satellite (e.g., the first satellite SAT#1) and may switch to the next coverage area.

[0706] In some embodiments, a communication system (e.g., an NR system) may support Figure 5 , Figure 6 and / or Figure 7 When the communication system supports more than one satellite switching procedure, the NW may indicate which satellite switching procedure is used in the current NW operation (e.g., based on Figure 5 , Figure 6 or Figure 7 In some implementations, the NW may indicate the parameters of the satellite switching procedure to be used by the UE via system information (eg, SIB), dedicated signaling (eg, RRC message), MAC CE, or DCI configuration.

[0707] In some embodiments, according to Figure 5 , Figure 6 and / or Figure 7 In the satellite switching process described, UE action #1 is performed before UE action #2.

[0708] Figure 8 8 is a flow chart of a method / process 800 for satellite switching according to an exemplary embodiment of the present application. In some embodiments, process 800 may be performed by a UE. It should be noted that although Figure 8 In the example, actions 802, 804, 806, and 808 are shown as separate actions, represented as independent blocks, but these separate actions should not be interpreted as necessarily dependent on the order. Figure 8 The order in which the actions are performed should not be interpreted as a limitation, and any number of disclosed frames can be combined in any order to implement the method or alternative method. In addition, each of actions 802, 804, 806, and 808 can be performed independently of other actions, and can be omitted in some embodiments of the present application.

[0709] In some implementations, the UE may perform a satellite handover from a source satellite to a target satellite in process 800. The source satellite and the target satellite may, for example, be associated with or belong to the same cell (eg, a serving cell).

[0710] refer to Figure 8 In action 802, process 800 may start by acquiring a first configuration related to a target satellite from a cell, the first configuration including a timestamp and time information. Specifically, in action 802, the UE may be served by a cell or a source satellite provided by a source satellite.

[0711] In some implementations, the UE may acquire the first configuration associated with the target satellite from a cell provided by the source satellite. In other words, the UE may acquire the first configuration associated with the target satellite from the source satellite.

[0712] In some implementations, the UE may acquire the first configuration related to the target satellite from a cell provided by the target satellite. In other words, the UE may acquire the first configuration related to the target satellite from the target satellite.

[0713] In some embodiments, acquiring the first configuration associated with the target satellite may include receiving system information (SI) broadcast by a cell, wherein the SI may include the first configuration associated with the target satellite. The SI may include at least one of SIB1 and SIB19.

[0714] In some implementations, the acquired first configuration may be carried in an RRC message. In this case, the first configuration may, for example, include one or more RRC parameters or IEs.

[0715] In some embodiments, the first configuration associated with the target satellite may further include a common timing advance (TA) parameter of the target satellite and an ephemeris of the target satellite, but the present application does not limit the details of the first configuration.

[0716] Reference again Figure 8 In act 804, process 800 may perform DL synchronization with the target satellite starting from the time indicated by the timestamp based on the time information.

[0717] In some implementations, the timestamp included in the first configuration may indicate a time 10 milliseconds after 00:00:00 on January 1, 1900 (eg, Gregorian calendar).

[0718] In some embodiments, the time information may be used to determine the time of an SSB transmission from a target satellite.

[0719] In some embodiments, the time information included in the first configuration may include the time information in the above reference Figures 5 to 7 For example, the time information may be related to or associated with a SSB transmitted from a target satellite. For example, the time information may be in units of subframes.

[0720] In some implementations, when performing DL synchronization with a target satellite, the UE may receive an SSB of the target satellite based on time information.

[0721] In some implementations, at the time indicated by the timestamp, the UE may start or restart the timer based on the timer information. The timer information may, for example, be included in the first configuration associated with the target satellite and received in action 802. The timer information may include, for example, the duration of the timer.

[0722] In some embodiments, the timer started at the time indicated by the timestamp may include a first timer (eg, represented as timer #1), as described above with reference to Figure 6 and Figure 7 In some implementations, the timer may be started by an RRC entity of the UE. In other words, the timer may be an RRC timer.

[0723] In some embodiments, after the timer expires, the UE may perform a specific action (e.g., UE action #2, as described above with reference to Figures 5 to 7 In other words, the timer can be configured to control the validity of uplink synchronization during the connection with the source satellite.

[0724] Reference again Figure 8In act 806, process 800 can retrieve a second configuration associated with the target satellite from the target satellite.

[0725] In some implementations, the UE may reacquire the second configuration associated with the target satellite from the target satellite after performing DL synchronization with the target satellite.

[0726] In some implementations, the UE may reacquire the second configuration associated with the target satellite from a cell provided by the target satellite.

[0727] In some embodiments, reacquiring the second configuration associated with the target satellite may include receiving SI broadcast by a cell, wherein the SI may include the second configuration associated with the target satellite. The SI may include at least one of SIB1 and SIB19.

[0728] In some implementations, the retrieved second configuration may be carried in an RRC message. In this case, the second configuration may, for example, include one or more RRC parameters or IEs.

[0729] In some implementations, the reacquired second configuration related to the target satellite may further include a public TA parameter of the target satellite and an ephemeris of the target satellite, but the present application does not limit the details of the reacquired second configuration.

[0730] Reference again Figure 8 In act 808, process 800 may calculate a common TA and a UE-specific TA based on the reacquired second configuration associated with the target satellite. Process 800 may then end.

[0731] In some embodiments, the UE may calculate the common TA and the UE-specific TA based on the common TA parameters and the ephemeris of the target satellite contained in the reacquired second configuration.

[0732] Therefore, even if the source satellite stops serving the UE's current coverage area, the UE may be served by a target satellite instead of the source satellite, or by a cell provided by the target satellite instead of the source satellite.

[0733] Fig. 9 is a block diagram showing a node 900 for wireless communication according to an exemplary embodiment of the present application. Fig. 9 As shown, the node 900 may include a transceiver 920, a processor 928, a memory 934, one or more presentation components 938, and at least one antenna 936. The node 900 may also include a radio frequency (RF) spectrum band module, a BS communication module, a network communication module, a system communication management module, an input / output (I / O) port, an I / O component, and a power supply ( Fig. 9 not shown).

[0734] Each component can communicate with each other directly or indirectly via one or more buses 40. Node 00 can be a reference Figures 1 to 8 Disclose various functions of UE or BS.

[0735] The transceiver 920 has a transmitter 922 (e.g., transmitting circuit / transmitting circuit) and a receiver 924 (e.g., receiving / receiving circuit), and can be configured to transmit and / or receive time and / or frequency resource partitioning information. The transceiver 920 can be configured to transmit in different types of subframes and time slots, including but not limited to available, unavailable and flexibly available subframe and time slot formats. The transceiver 920 can be configured to receive data and control channels.

[0736] Node 900 may include various computer-readable media. Computer-readable media may be any available media that can be accessed by node 900 and includes both volatile (and / or nonvolatile) media and removable (and / or non-removable) media.

[0737] Computer readable media may include computer storage media and communication media. Computer storage media may include volatile (and / or non-volatile) and removable (and / or non-removable) media implemented in any method or technology for storing information such as computer readable instructions, data structures, program modules, or data.

[0738] Computer storage media include RAM, ROM, EEPROM, flash memory (or other storage technology), CD-ROM, Digital Versatile Disk (DVD) (or other optical disk storage device), magnetic tape cassette, magnetic tape, magnetic disk storage (or other magnetic storage device), etc. Computer storage media do not include propagated data signals. Communication media may typically embody computer readable instructions, data structures, program modules or other data in a modulated data signal (such as a carrier wave or other transport mechanism), and include any information delivery media.

[0739] The term "modulated data signal" may refer to a signal that has one or more characteristics set or changed in such a manner as to encode information in the signal. By way of example and not limitation, communication media include wired media (such as a wired NW or direct-wired connection) and wireless media (such as acoustic, RF, infrared and other wireless media). Any combination of the foregoing disclosures should also be included within the scope of computer-readable media.

[0740] The memory 934 may include computer storage media in the form of volatile and / or non-volatile memory. The memory 934 may be removable, non-removable, or a combination thereof. For example, the memory 934 may include solid-state memory, a hard drive, an optical drive, etc. Fig. 9 As shown, the memory 934 can store computer-readable and / or computer-executable instructions 932 (e.g., software code or computer-executable program) that are configured to cause the processor 928 to perform various functions described herein when executed, such as, for example, referring to Figures 1 to 9 Alternatively, the computer executable instructions 932 may not be directly executable by the processor 928, but may be configured to cause the node 900 (eg, when compiled and executed) to perform various functions described herein.

[0741] The processor 928 (e.g., having a processing circuit) may include an intelligent hardware device, such as a central processing unit (CPU), a microcontroller, an ASIC, etc. The processor 928 may include a memory. The processor 928 may process data 930 and instructions 932 received from the memory 934, and information passed through the transceiver 920, the baseband communication module, and / or the network communication module. The processor 928 may also process information to be transmitted to the transceiver 920 for transmission through the antenna 936 and to be transmitted to the network communication module for transmission to the core network (CN).

[0742] One or more presentation components 938 can present data indications to a person or another device. Examples of presentation components 938 can include a display device, a speaker, a printing component, a vibration component, etc.

[0743] In view of the present application, various technologies can be used to implement the disclosed concepts without departing from the scope of these concepts. In addition, although these concepts have been disclosed with specific reference to certain implementations, it will be appreciated by those of ordinary skill in the art that changes can be made in form and detail without departing from the scope of those concepts. Therefore, the disclosed embodiments are considered to be illustrative and not restrictive in all respects. It should also be understood that the present application is not limited to the disclosed specific embodiments. Nevertheless, many rearrangements, modifications and substitutions are possible without departing from the scope of the present application.

Claims

1. A satellite switching method performed by a user equipment UE, characterized in that: The method comprises: Acquire a first configuration associated with a first satellite from a cell, the first configuration comprising a timestamp and time information; Based on the time information, performing downlink DL synchronization with the first satellite starting from the time indicated by the timestamp; reacquiring a second configuration associated with the first satellite from the first satellite; and A common timing advance and a UE-specific timing advance are calculated based on the reacquired second configuration associated with the first satellite.

2. The method according to claim 1, characterized in that The first configuration associated with the first satellite also includes timer information, and the method further includes: At the time indicated by the timestamp, a timer is started based on the timer information.

3. The method according to claim 2, characterized in that The timer includes a radio resource control RRC timer.

4. The method according to claim 2, characterized in that: Acquiring the first configuration associated with the first satellite from the cell includes acquiring the first configuration associated with the first satellite from a second satellite, and The timer is configured to control the validity of uplink synchronization during the connection with the second satellite.

5. The method according to claim 1, characterized in that Acquiring the first configuration related to the first satellite from the cell includes: The first configuration associated with the first satellite is obtained from a second satellite, wherein the first satellite and the second satellite are both associated with the cell.

6. The method according to claim 1, characterized in that: Acquiring the first configuration related to the first satellite from the cell includes receiving system information broadcast by the cell, and The system information includes the first configuration associated with the first satellite.

7. The method according to claim 6, characterized in that The system information includes at least one of system information block type 1 SIB1 and system information block type 19 SIB19.

8. The method according to claim 1, characterized in that: Performing the DL synchronization with the first satellite comprises: A synchronization signal block SSB of the first satellite is received based on the time information.

9. The method according to claim 8, characterized in that The time information is associated with the SSB and is in units of subframes.

10. The method according to claim 1, characterized in that Retrieving the second configuration associated with the first satellite from the first satellite comprises: After performing the DL synchronization with the first satellite, the second configuration associated with the first satellite is reacquired from the first satellite.

11. A user equipment UE, characterized in that: include: one or more non-transitory computer-readable media storing one or more computer-executable instructions; as well as at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the one or more computer-executable instructions to cause the UE to: Acquire a first configuration associated with a first satellite from a cell, the first configuration comprising a timestamp and time information; Based on the time information, performing downlink DL synchronization with the first satellite starting from the time indicated by the timestamp; reacquiring a second configuration associated with the first satellite from the first satellite; as well as A common timing advance and a UE-specific timing advance are calculated based on the reacquired second configuration associated with the first satellite.

12. The UE according to claim 11, characterized in that: The first configuration associated with the first satellite also includes timer information, and When executed by the at least one processor, the one or more computer executable instructions further cause the UE to: At the time indicated by the timestamp, a timer is started based on the timer information.

13. The UE according to claim 12, characterized in that: The timer includes a radio resource control RRC timer.

14. The UE according to claim 12, characterized in that: Acquiring the first configuration associated with the first satellite from the cell includes acquiring the first configuration associated with the first satellite from a second satellite, and The timer is configured to control the validity of uplink synchronization during the connection with the second satellite.

15. The UE according to claim 11, characterized in that: Acquiring the first configuration related to the first satellite from the cell includes: The first configuration associated with the first satellite is obtained from a second satellite, wherein the first satellite and the second satellite are both associated with the cell.

16. The UE according to claim 11, characterized in that: Acquiring the first configuration related to the first satellite from the cell includes receiving system information broadcast by the cell, and The system information includes the first configuration associated with the first satellite.

17. The UE according to claim 16, characterized in that: The system information includes at least one of system information block type 1 SIB1 and system information block type 19 SIB19.

18. The UE according to claim 11, characterized in that: Performing the DL synchronization with the first satellite comprises: A synchronization signal block SSB of the first satellite is received based on the time information.

19. The UE according to claim 18, characterized in that The time information is associated with the SSB and is in units of subframes.

20. The UE according to claim 11, characterized in that Retrieving the second configuration associated with the first satellite from the first satellite comprises: After performing the DL synchronization with the first satellite, the second configuration associated with the first satellite is reacquired from the first satellite.

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