Timing synchronization method and apparatus for handover in non-terrestrial network communication

Abstract

Various uplink synchronization schemes in NTN communication are described. An apparatus implemented as a User Equipment (UE) receives the SIB of a target cell through an NT network node of the NTN. The apparatus obtains the explicit epoch time from the SIB of the target cell. The apparatus adjusts the uplink transmission time according to the explicit epoch time to perform UL synchronization with the target cell.

Description

[0001] Cross-references

[0002] This invention claims priority to U.S. Provisional Patent Application No. 63 / 245,233, filed September 17, 2021, and U.S. Patent Application No. 17 / 865,147, filed July 14, 2022, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention generally relates to mobile communications. More specifically, this invention relates to timing synchronization during handover in non-terrestrial network (NTN) communications. Background Technology

[0004] Unless otherwise stated herein, the methods described in this section are not prior art to the claims listed below, and are not acknowledged as prior art by virtue of their inclusion in this section.

[0005] The satellite communications industry is showing increasing interest and participation in the 3rd Generation Partnership Project (3GPP), with some companies and organizations believing that 3GPP's fifth generation (5GPP) will be a significant step forward. th The market potential of integrating satellite and terrestrial network infrastructure in the 5G (Generation 5G) environment. Satellites refer to spacecraft in Low Earth Orbit (LEO), Medium Earth Orbit (MEO), Geostationary Earth Orbit (GEO), or Highly Elliptical Orbit (HEO). The 5G standard makes NTN, including satellite segments, a recognized component of the 3GPP 5G connectivity infrastructure. Low Earth Orbit is a geocentric orbit with an altitude of 2000 km or less, or at least 11.25 cycles per day with an eccentricity of less than 0.25. Most man-made objects in outer space are located in LEO. LEO satellites orbit the Earth at high speeds (mobility) but operate in predictable or deterministic orbits.

[0006] In 4G Long-Term Evolution (LTE) and 5G New Radio (NR) networks, the evolved universal terrestrial radio access network (E-UTRAN) includes multiple base stations, such as evolved Node-Bs (eNodeBs) that communicate with multiple mobile stations (called user equipment, UEs). In 5G NR, base stations are also called gNodeBs or gNBs. For UEs in Radio Resource Control (RRC) idle mode mobility, cell selection is the process by which the UE selects a specific cell for initial registration after power-on, and cell reselection is the mechanism by which the UE changes cells after camping on a cell and maintaining idle mode. For UEs in RRC connected mode mobility, handover is the process by which the UE switches an ongoing session from a source gNB to a neighboring target gNB.

[0007] Mobility in LEO satellite-based NTNs can differ significantly from that in terrestrial networks. In terrestrial networks, cells are fixed, but UEs can move along different trajectories. In NTNs, however, most LEO satellites operate at a constant speed relative to the Earth's surface, while UE movement is relatively slow and negligible. For LEO satellites, although in a predictable manner, cells move over time. Therefore, LEO satellites can estimate the target cell based on their own moving speed, direction, and altitude, rather than relying on UE measurement reports. Once an LEO satellite moves to a new cell, most (if not all) UEs will be switched to the same target cell. The network can estimate the UE's position by using the Global Navigation Satellite System (GNSS) or by capturing position information from the core network.

[0008] The handover process in NR-based LEO-NTN involves frequent, periodic handover messages. Naturally, traditional handover based on UE measurement-reports (MRs) incurs frequent and heavy signaling overhead, as the network needs to process MRs, trigger HO decisions, and continue HO signaling every few seconds. A System Information Block (SIB) can be used in the NTN to serve satellite / gNB synchronization. The NTN synchronization SIB will contain ephemeris information such as satellite position vectors, satellite velocity vectors, and orbital parameters.

[0009] During handover, to minimize interruptions, UE decoding of SIB information is not expected. During the handover process, satellite-aided system information broadcast on the SIB is provided to the UE via RRC configuration. However, if the target cell is an NTN, and if the NTN SIB uses an implicit time reference to determine the validity of downlink (DL) reception content or epoch time, forwarding the NTN SIB as is will not allow the UE to synchronize its uplink (UL) and send the RACH preamble. Therefore, in NR-NTN, the target cell's time information needs to be explicitly sent to the UE before the handover process begins. Summary of the Invention

[0010] The following overview is illustrative only and is not intended to be limiting in any way. That is, it is provided to introduce the concepts, key points, benefits, and advantages of the novel and non-obvious techniques described herein. The chosen embodiments will be further described in detail below. Therefore, the following overview is not intended to identify the essential features of the claimed subject matter, nor is it intended to determine the scope of the claimed subject matter.

[0011] One object of the present invention is to provide solutions, designs, concepts, techniques, methods, systems, and apparatuses for solving the aforementioned problems. Specifically, the various solutions proposed in this invention are believed to solve problems related to uplink synchronization with the target cell during NTN communication handover.

[0012] In one aspect, a method relates to an apparatus for acquiring a carrier frequency of an NTN. The method further relates to the apparatus receiving a target cell's SIB via a non-terrestrial (NT) network node of the NTN. The method also relates to the apparatus acquiring an explicit epoch time from the target cell's SIB. The method further relates to the apparatus adjusting its uplink transmission time based on the explicit epoch time to perform UL synchronization with the target cell.

[0013] In another aspect, an apparatus includes a transceiver and a processor coupled to the transceiver. The transceiver is configured to wirelessly communicate with an NTN. The processor is configured to receive the SIB of a target cell via the transceiver through an NT network node of the NTN. The processor also obtains an explicit epoch time from the SIB of the target cell. The processor can also adjust the uplink transmission time based on the explicit epoch time to perform UL synchronization with the target cell.

[0014] In another aspect, an apparatus includes a transceiver and a processor coupled to the transceiver. The transceiver is configured to wirelessly communicate with an NTN. The processor is configured to receive an SIB from a target cell via the transceiver through an NT network node of the NTN. The processor can also decode the SIB to obtain the explicit epoch time of the target cell before completing a handover process. The processor can also adjust the uplink transmission time based on the explicit epoch time to perform UL synchronization with the target cell.

[0015] It is worth noting that although the description provided herein is set against the backdrop of certain wireless access technologies, networks, and network topologies, such as LTE, LTE-Advanced and LTE-Advanced Pro, 5G, NR, Internet of Things (IoT), Narrow Band Internet of Things (NB-IoT), Industrial Internet of Things (IIoT), NTN, and 6th Generation (6G), the concepts, schemes, and any variations / derivatives of this invention can be implemented in other types of access technologies, networks, and network topologies. Therefore, the scope of this invention is not limited to the examples described herein. Attached Figure Description

[0016] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. It is understood that, in order to clearly illustrate the concepts of the invention, the drawings are not necessarily drawn to scale, and some components may be shown out of proportion to their actual dimensions in the embodiments.

[0017] Figure 1 This is an example network environment diagram that can implement the various solutions proposed in this invention.

[0018] Figure 2 This is a block diagram of an example communication system according to an embodiment of the present invention.

[0019] Figure 3 This is a flowchart of an example process according to an embodiment of the present invention.

[0020] Figure 4 This is a flowchart of an example process according to an embodiment of the present invention. Detailed Implementation

[0021] The embodiments and implementations of the claimed subject matter are described in detail below. However, it should be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matter implemented in various forms. The invention can be implemented in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that the description of the invention is thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the following description, known features and technical details are omitted to avoid unnecessarily obscuring the presented embodiments and implementations.

[0022] Overview

[0023] The embodiments of the present invention relate to various techniques, methods, schemes, and / or solutions for uplink synchronization with the target cell during NTN communication handover. According to the present invention, many possible solutions can be implemented individually or in combination. That is, although these possible solutions are described individually below, two or more of these possible solutions can be implemented in one combination or another.

[0024] Figure 1 An example network environment 100 supporting efficient handover procedures in LEO NTN according to the present invention is illustrated. Network environment 100 involves at least one NT network node 120 (e.g., a satellite), at least one UE 110, and multiple terrestrial network nodes 131, 132 (e.g., gateways, base stations, eNBs, gNBs, or transmission / reception points (TRPs)), which may be part of a wireless communication network (e.g., an LTE network, a 5G network, an NR network, an IoT network, an NB-IoT network, an IIoT network, an NTN network, or a 6G network).

[0025] UE 110 may be located far from ground network nodes 131 and 132 (e.g., outside the communication range of ground network nodes 131 and 132) and cannot communicate directly with them. Via the NTN, UE 110 can send signals to / receive signals from the NT network node 120. NT network node 120 can relay / transmit signals / data from UE 110 to one of the ground network nodes 131 and 132. Therefore, one of the ground network nodes 131 and 132 can communicate with UE 110 through NT network node 110. Figure 1In this example, NT network node 120 operates at high speed (mobility) around the Earth, but on a predictable or deterministic trajectory, and UE 110 is initially served in terrestrial network node 131 (hereinafter referred to as source cell 131). Once NT network node 120 moves to a new cell, UE 110 will be switched to terrestrial network node 132 (hereinafter referred to as target cell 132).

[0026] For NT network node 120, although in a predictable manner, ground network nodes 131 and 132 move over time. Therefore, NT network node 120 can estimate the target cell based on its own moving speed, direction, and altitude, rather than relying on UE measurement reports. Once NT network node 120 moves to a new cell, most (if not all) of the UEs will be switched to the same target cell. The network can estimate the UE's location by using GNSS or by capturing location information from the core network.

[0027] For UE 110 moving in RRC connected mode, handover refers to the process by which UE 110 switches its ongoing session from source cell 131 to the neighboring target cell 132. Before switching to target cell 132, UE 110 needs to obtain system information (e.g., master information block (MIB) and SIB) of target cell 132. The SIB can be used in the NTN for synchronization with terrestrial network nodes 131 and 132. The SIB can also be used in the NTN for serving satellite / gNB synchronization.

[0028] During handover, to minimize interruptions, UE decoding of SIB information is not expected. Source cell 131 provides RRC configuration to UE 110 by forwarding the RRC Reconfiguration message received in the Handover Request Acknowledgment (HANDOVER REQUEST ACKNOWLEDGE). The RRC Reconfiguration message includes at least the cell ID and all the information required to access target cell 132, allowing UE 110 to access the target cell without reading system information. However, if the SIB uses an implicit time reference to determine what needs to be received by DL or the validity of the epoch time, forwarding the NTNSIB as is will not allow UE 110 to synchronize its UL to target cell 132 and send the RACH preamble. In this case, UE 110 may require downlink reception for UL timing synchronization.

[0029] In view of the above, the present invention proposes several schemes related to uplink synchronization with the target cell during NTN communication handover for UE 110, NT network node 120, and ground network node 130. According to the various schemes proposed in the present invention, UE 110, NT network node 120, and ground network node 130 are configured to perform operations related to SIB and explicit epoch time for uplink synchronization with the target cell during the handover process in NTN communication, as described below.

[0030] According to the proposed scheme, UE 110 can receive the SIB of the target cell through the NT network node of the NTN. Furthermore, UE 110 can obtain the explicit epoch time from the SIB of the target cell. Then, UE 110 can perform UL synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time.

[0031] In some embodiments, UE 110 obtains the SIB of target cell 132 from source cell 131. Specifically, when NT network node 120 moves to target cell 132, target cell 132 can send its SIB to source cell 131. Since UE 110 is still served by source cell 131 and is in RRC connection mode, source cell 131 can send an RRC configuration signal (e.g., an RRCConfiguration message) to NT network node 120 for configuring the SIB of target cell 132. Then, the NT network node forwards the RRC configuration information to UE 110.

[0032] The SIB includes at least the explicit epoch time of the target cell 132 and the satellite ephemeris of the NT network node 120. The satellite ephemeris includes at least one of the following: satellite position vector, satellite velocity vector, feeder link timing advance (TA) parameter, feeder link delay parameter, multiple satellite orbital parameters, and trajectory information. The satellite position vector and satellite velocity vector are located in an Earth-centered, Earth-fixed (ECEF) coordinate system or another reference system. In some embodiments, the SIB information may also include other information, such as feeder link delay or timing advance, but is not limited thereto.

[0033] The explicit epoch time can be the DL timing of the target cell and includes, but is not limited to, one or any combination of the system frame number (SFN), subframe index, slot index, symbol number, and coordinated universal time (UTC). In some embodiments, UL timing may also be used. Once the explicit epoch time is obtained, UE 110 can synchronize its uplink transmission time with the target cell 132 and perform a handover procedure by switching from source cell 131 to target cell 132 according to SIB.

[0034] Since UE 110 does not decode SIB, the handover interruption time during the handover process is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available PRACH opportunity in the target cell, processing time, timing information acquisition time, and SSB post-processing time, and can be calculated as T. interrupt =T search +T IU +T processing +T Δ +T margin_ms T interrupt Indicates the handover interruption time. T search This represents the cell search time, which is the time required for UE110 to search for the target cell 132 when it receives a handover command. IU This represents the interruption uncertainty time, specifically the interruption uncertainty when acquiring the first available PRACH in a new cell. T processing This indicates the processing time for the UE, which can be as long as 20ms. Δ This indicates the timing information acquisition time, which is used for fine-grained time tracking and acquiring complete timing information for the target cell 132. margin_ms This indicates the SSB post-processing time.

[0035] According to another proposed scheme, UE 110 can receive the SIB from target cell 132 via NT network node 120. Then, UE 110 decodes the SIB before completing the handover process. Specifically, target cell 132 can broadcast the SIB, and NT network node 120 forwards the SIB to UE 110. To access target cell 132, UE 110 must decode the SIB. Therefore, the handover interruption time is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available PRACH opportunity in the target cell, processing time, timing information acquisition time, SIB decoding time, and SSB post-processing time, and can be calculated as T. interrupt =T search +T IU+T processing +T Δ +T SIB +T margin_ms T SIB This indicates the SIB decoding time, which is the time it takes for UE 110 to decode the SIB. The SIB decoding time is determined based on system information scheduling.

[0036] Illustrative Implementation

[0037] Figure 2 An example communication system 200, comprising at least an example communication device 210 and an example network device 220 according to an embodiment of the present invention, is illustrated. Either the communication device 210 or the network device 220 can perform various functions to implement the schemes, techniques, processes, and methods described herein regarding the synchronization of SIBs and explicit epoch times with the uplink of the target cell during handover procedures in NTN communication, including the scenarios / schemes described above and processes 300 and 400 described below.

[0038] The communication device 210 may be part of an electronic device, such as a portable or mobile device, a wearable device, a wireless communication device, or a UE (User Equipment) of a computing device. For example, the communication device 210 may be implemented as a smartphone, smartwatch, personal digital assistant, digital camera, or computing device such as a tablet computer, desktop computer, or laptop computer. The communication device 210 may also be part of a machine-type device, such as an IoT, NB-IoT, or IIoT device, or an NTN (Network Terminal Network) device, such as a fixed device, home device, wired communication device, or computing device. For example, the communication device 210 may be implemented as a smart thermostat, smart refrigerator, smart door lock, wireless speaker, or home control center.

[0039] Furthermore, the communication device 210 can be implemented as one or more integrated circuit (IC) chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction-set computing (RISC) processors, or one or more complex-instruction-set computing (CISC) processors. The communication device 210 includes at least... Figure 2 Some of the components shown, such as processor 212. Communication device 210 may also include one or more other components unrelated to the proposed solution (e.g., internal power supply, display device, and / or user interface device). For simplicity, the aforementioned other components of communication device 210 are not shown. Figure 2The middle part will not be described below.

[0040] Network device 220 may be part of an electronic device / station, such as a base station, cell, router, gateway, or satellite. For example, network device 220 may be implemented in an eNodeB in LTE, a gNB in ​​5G, NR, 6G, IoT, NB-IoT, or IIoT, or in a satellite in an NTN network. Additionally, network device 220 may be implemented as one or more IC chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more RISC processors, or one or more CISC processors. Network device 220 includes at least... Figure 2 Some of the components shown are, for example, processor 222. Network device 220 may also include one or more other components (e.g., internal power supply, display device, and / or user interface device) unrelated to the proposed solution. For simplicity, the aforementioned other components of network device 220 are not shown. Figure 2 The middle part will not be described below.

[0041] On one hand, either processor 212 or processor 222 may be implemented as one or more single-core processors, one or more multi-core processors, one or more CISC processors, or one or more RISC processors. That is, even though the singular term "processor" is used herein to refer to processor 212 and processor 222, in this invention, either processor 212 or processor 222 may include multiple processors in some embodiments and a single processor in others. On the other hand, either processor 212 or processor 222 may be implemented as hardware (and optionally, firmware) with electronic components, including, for example, but not limited to, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors, and / or one or more varactor diodes configured for a particular purpose according to the invention. In other words, at least in some embodiments, processor 212 and processor 222 are specific target machines specifically designed, arranged, and configured to perform specific tasks related to uplink synchronization with a target cell during NTN communication handover according to various embodiments of the invention.

[0042] In some embodiments, the communication device 210 further includes a transceiver 216 coupled to the processor 212 and capable of wirelessly transmitting and receiving data. In some embodiments, the communication device 210 further includes a memory 214 coupled to the processor 212 and accessible by the processor 212 and storing data therein. In some embodiments, the network device 220 further includes a transceiver 226 coupled to the processor 222 and capable of wirelessly transmitting and receiving data. In some embodiments, the network device 220 further includes a memory 224 coupled to the processor 222 and accessible by the processor 222 and storing data therein. Therefore, the communication device 210 and the network device 220 communicate wirelessly with each other via transceiver 216 and transceiver 226, respectively.

[0043] Either the communication device 210 and the network device 220 can be a communication entity capable of communicating with each other using various schemes proposed according to the present invention. To aid better understanding, the following description of the operation, function, and capabilities of each of the communication device 210 and the network device 220 is provided in the context of a mobile communication environment, in which the communication device 210 is implemented in or as a communication device or UE (e.g., UE 110), and the network device 220 is implemented in or as a network node or base station of a communication network (e.g., NT network node 120 and terrestrial network node 130). It is also worth noting that although the example embodiments described below are provided in the context of NTN communication, they can also be implemented in other types of networks.

[0044] According to various schemes proposed by the present invention regarding the SIB and explicit epoch time for uplink synchronization with the target cell during the handover process in NTN communication, the processor 212 of the communication device 210 (implemented in UE 110, or implemented as UE 110) receives the SIB of the target cell through the NT network node of the NTN. The processor 212 can obtain the explicit epoch time from the SIB of the target cell via transceiver 216. The processor 212 performs UL synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time. The explicit epoch time includes SFN, subframe index, slot index, symbol number, UTC, or any combination thereof.

[0045] The SIB includes the satellite ephemeris of NT network node 120. The satellite ephemeris includes at least one of the following: satellite position vector, satellite velocity vector, feeder link TA parameters, feeder link delay parameters, multiple satellite orbital parameters, and trajectory information. The satellite position vector and satellite velocity vector are located in the ECEF coordinate system or another reference system.

[0046] In some implementations, processor 212 may receive an RRC configuration signal for configuring the SIB from the source cell.

[0047] In some implementations, the processor 212 can perform the handover process by switching from the source cell to the target cell based on the SIB.

[0048] According to various schemes proposed by the present invention regarding the SIB and explicit epoch time for uplink synchronization with the target cell during the handover process in NTN communication, the processor 212 of the communication device 210 (implemented in UE 110, or implemented as UE 110) can receive the SIB from the target cell via a transceiver through the NT network node of the NTN, and decode the SIB to obtain the explicit epoch time of the target cell before completing the handover process. The processor can perform UL synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time.

[0049] The handover interruption time is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available PRACH opportunity in the target cell, processing time, timing information acquisition time, SIB decoding time, and SSB post-processing time.

[0050] SIB decoding time is determined based on system information scheduling.

[0051] Explanatory process

[0052] Figure 3 An example process 300 according to an embodiment of the present invention is described. Whether partially or entirely, process 300 may be an example implementation of the scheme proposed according to the present invention regarding the synchronization of SIBs and explicit epoch times with the uplink of the target cell during the handover process. Process 300 may represent one aspect of an implementation of the features of communication device 210. Process 300 may include one or more operations, actions, or functions, as shown in one or more of steps 310, 320, and 330.

[0053] Although described as discrete steps, the individual steps of process 300 can be divided into additional steps, combined into fewer steps, or deleted as needed. Furthermore, the steps / substeps of process 300 can be arranged according to… Figure 3 The process 300 is executed in the order shown, or in any other order. This is for illustrative purposes only, but is not a limitation thereof, and is described in the context of communication device 210.

[0054] Process 300 begins at step 310. At step 310, process 300 involves the processor 212 of communication device 210 receiving the SIB of the target cell through the NT network node of the NTN. Process 300 proceeds from step 310 to step 320.

[0055] At step 320, process 300 involves processor 212 obtaining the explicit epoch time from the SIB of the target cell. Process 300 proceeds from step 320 to step 330.

[0056] At step 330, process 300 involves processor 212 performing UL synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time.

[0057] In some implementations, explicit epoch time includes one or any combination of SFN, subframe index, slot index, symbol number, UTC.

[0058] In some implementations, the SIB includes the satellite ephemeris of the NT network node 120. The satellite ephemeris includes at least one of the following: satellite position vector, satellite velocity vector, feeder link TA parameters, feeder link delay parameters, multiple satellite orbital parameters, and trajectory information. The satellite position vector and satellite velocity vector are located in the ECEF coordinate system or another reference system.

[0059] Figure 4 An example process 400 according to an embodiment of the present invention is described. Whether in part or in whole, process 400 may be an example implementation of the scheme proposed according to the present invention regarding the synchronization of SIBs and explicit epoch times with the uplink of the target cell during the handover process. Process 400 may represent one aspect of an implementation of the features of communication device 210. Process 400 may include one or more operations, actions, or functions, as shown in one or more of steps 410, 420, and 430.

[0060] Although described as discrete steps, the individual steps of process 400 can be divided into additional steps, combined into fewer steps, or deleted as needed. Furthermore, the steps / substeps of process 400 can be arranged according to… Figure 4 The process 400 is executed in the order shown, or in any other order. This is for illustrative purposes only, but is not a limitation thereof, and is described in the context of communication device 210.

[0061] Process 400 begins at step 410. At step 410, process 400 involves the processor 212 of communication device 210 receiving the SIB of the target cell through the NT network node of the NTN. Process 400 proceeds from step 410 to step 420.

[0062] At step 420, process 400 involves processor 212 decoding the SIB to obtain the explicit epoch time of the target cell before completing the handover process. Process 400 proceeds from step 420 to step 430.

[0063] At step 430, process 300 involves processor 212 performing UL synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time.

[0064] In some implementations, the handover interruption time is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available PRACH opportunity in the target cell, processing time, timing information acquisition time, SIB decoding time, and SSB post-processing time.

[0065] In some implementations, the SIB decoding time is determined based on system information scheduling.

[0066] Supplementary Explanation

[0067] The subject matter described in this invention sometimes exemplifies different components included within or connected to other components. It should be understood that the architectures depicted are merely examples, and in reality, many other architectures can be implemented to achieve the same functionality. Conceptually, any arrangement of components used to achieve the same functionality is effectively “associated” to achieve the desired function. Therefore, any two components combined in this invention to achieve a particular function can be considered “associated” with each other to achieve the desired function, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered “operably connected” or “operably coupled” to each other to achieve the desired function, and any two components that can be so associated can also be considered “operably coupled” to each other to achieve the desired function. Specific examples of operably coupled include, but are not limited to, physically pairable and / or physically interactive components and / or wirelessly interactive and / or logically interactive and / or logically interactive components.

[0068] Furthermore, in relation to virtually any use of plural and / or singular terms in this invention, those skilled in the art may convert plural to singular and / or singular to plural to suit the context and / or application. For clarity, various singular / plural substitutions may be explicitly described in this invention.

[0069] Furthermore, those skilled in the art should understand that, in general, the terms used in this invention, particularly in the appended claims (e.g., the body of the appended claims), are typically intended as “open” terms. For example, the term “comprising” should be interpreted as “including but not limited to,” and the term “having” should be interpreted as “having at least,” etc. Those skilled in the art should also understand that if there is an intention to refer to a specific number of claim statements, this intention will be explicitly stated in the claims, and without such a statement, this intention does not exist. For example, to aid understanding, the following appended claims may include the use of the introductory phrases “at least one” and “one or more” to introduce claim statements. However, the use of these phrases should not be construed as implying that introducing a claim statement with the indefinite article “a” or “an” limits any particular claim that includes this introduced claim statement to an implementation that includes only this one statement, even when the claim includes the introductory phrase “one or more” or “at least one” and indefinite articles such as “a” or “an,” for example, “a” and / or “an” should be interpreted as meaning “at least one” and “one or more,” the same applies to the use of definite articles for introducing claim statements. Furthermore, even in claims that explicitly state a specific number, those skilled in the art will recognize that such a statement should be interpreted as meaning at least the stated number; for example, the plain statement "two statements" without other modifications means at least two statements or two or more statements. Moreover, in cases where the convention of "at least one of A, B, and C" is used, generally, from the perspective of those skilled in the art to understand this convention, the construction contemplated, for example, "a system having at least one of A, B, and C," will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. In other cases where the convention of "at least one of A, B, or C" is used, generally, from the perspective of those skilled in the art to understand this convention, the construction contemplated, for example, "a system having at least one of A, B, or C," will include, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc. Those skilled in the art should also understand that any conjunction and / or phrase (whether in the specification, claims, or drawings) that actually represents two or more alternative terms should be understood to imply the possibility of including one, any, or both of the terms. For example, the phrase “A or B” would be understood to include the possibility of including “A” or “B” or “A and B”.

[0070] Based on the foregoing, it should be understood that various embodiments of the invention have been described herein for illustrative purposes, and various modifications may be made without departing from the scope and spirit of the invention. Therefore, the various embodiments disclosed herein are not intended to be limiting, and the true scope and spirit are indicated by the claims.

Claims

1. A timing synchronization method for handover in non-terrestrial network communication, comprising: The device's processor receives system information blocks of the target cell through a non-terrestrial network node in a non-terrestrial network. The processor receives a radio resource control configuration signal from the source cell that configures the system information block; The processor obtains the explicit epoch time from the system information block of the target cell, the explicit epoch time including the system frame number and subframe index; as well as Once the explicit epoch time is obtained, the processor performs uplink synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time, and performs a handover process from the source cell to the target cell according to the system information block.

2. The timing synchronization method for handover in non-terrestrial network communication as described in claim 1, characterized in that, The explicit epoch time also includes a slot index, a symbol, Coordinated Universal Time (UTC), or any combination thereof.

3. The timing synchronization method for handover in non-terrestrial network communication as described in claim 1, characterized in that, The system information block includes the satellite ephemeris of the non-terrestrial network nodes.

4. The timing synchronization method for handover in non-terrestrial network communication as described in claim 3, characterized in that, The satellite ephemeris includes at least one of the following: satellite position vector, satellite velocity vector, feeder link timing advance parameter, feeder link delay parameter, multiple satellite orbit parameters, and trajectory information.

5. The timing synchronization method for handover in non-terrestrial network communication as described in claim 4, characterized in that, The satellite position vector and the satellite velocity vector are located in a coordinate system centered on the Earth and with the Earth fixed, or in another reference system.

6. A timing synchronization method for handover in non-terrestrial network communication, comprising: The device's processor receives system information blocks of the target cell through a non-terrestrial network node in a non-terrestrial network. The processor receives a radio resource control configuration signal from the source cell that configures the system information block; The processor decodes the system information block to obtain the explicit epoch time of the target cell before completing the handover process. The explicit epoch time includes the system frame number and the subframe index. as well as Once the explicit epoch time is obtained, the processor performs uplink synchronization with the target cell by adjusting the uplink transmission time according to the explicit epoch time, and performs a handover process from the source cell to the target cell according to the system information block.

7. The timing synchronization method for handover in non-terrestrial network communication as described in claim 6, characterized in that, The handover interruption time is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available physical random access channel in the target cell, processing time, timing information acquisition time, system information block decoding time, and synchronization signal block post-processing time.

8. A timing synchronization device for handover in non-terrestrial network communication, comprising: Transceivers are used for wireless communication with non-terrestrial networks; as well as A processor, coupled to the transceiver, is used to perform the following steps: Receive system information blocks of the target cell through non-terrestrial network nodes in a non-terrestrial network; The processor receives a radio resource control configuration signal from the source cell that configures the system information block; Obtain the explicit epoch time from the system information block of the target cell. The explicit epoch time includes the system frame number and the subframe index. as well as Once the explicit epoch time is obtained, uplink synchronization with the target cell is performed by adjusting the uplink transmission time according to the explicit epoch time, and a handover process from the source cell to the target cell is performed according to the system information block.

9. The apparatus as claimed in claim 8, characterized in that, The explicit epoch time also includes a slot index, a symbol, Coordinated Universal Time (UTC), or any combination thereof.

10. The apparatus as claimed in claim 8, characterized in that, The system information block includes the satellite ephemeris of the non-terrestrial network nodes.

11. The apparatus as claimed in claim 10, characterized in that, The satellite ephemeris includes at least one of the following: satellite position vector, satellite velocity vector, feeder link timing advance parameter, feeder link delay parameter, multiple satellite orbit parameters, and trajectory information.

12. The apparatus as claimed in claim 11, characterized in that, The satellite position vector and the satellite velocity vector are located in a coordinate system centered on the Earth and with the Earth fixed, or in another reference system.

13. A device for timing synchronization during handover in non-terrestrial network communication, comprising: Transceivers are used for wireless communication with non-terrestrial networks; as well as A processor, coupled to the transceiver, is used to perform the following steps: Receive system information blocks of the target cell through non-terrestrial network nodes in a non-terrestrial network; The processor receives a radio resource control configuration signal from the source cell that configures the system information block; The system information block is decoded to obtain the explicit epoch time of the target cell before the handover process is completed. The explicit epoch time includes the system frame number and the subframe index. as well as Once the explicit epoch time is obtained, uplink synchronization with the target cell is performed by adjusting the uplink transmission time according to the explicit epoch time, and the handover process from the source cell to the target cell is performed according to the system information block.

14. The apparatus as claimed in claim 13, characterized in that, The handover interruption time is the sum of at least one of the following: cell search time for searching the target cell, interruption uncertainty time for obtaining the first available physical random access channel in the target cell, processing time, timing information acquisition time, system information block decoding time, and synchronization signal block post-processing time.

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