A mechanism for transitioning to another cell without handover in non-terrestrial networks

Abstract

The present disclosure relates to a transition to another cell without handover in a non-terrestrial network (NTN). Specifically, an NTN device transmits information related to a set of NTN devices to a terminal, and a first device receives assistance information of the NTN device from a second device. The assistance information indicates at least a type of cell switch. The first device skips flushing a buffer and updating a security key regardless of the type of cell switch. In this way, a cell switch without handover can be realized.

Description

[Technical Field]

[0001] Various example embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods, devices, apparatus, and computer-readable storage media for transitioning to another cell without handover in a non-terrestrial network (NTN). [Background technology]

[0002] The 3rd Generation Partnership Project (3GPP) has initiated discussions regarding NTN. For example, the feasibility of supporting non-terrestrial networks using fifth-generation (5G) new radio (NR) standards was considered in 3GPP Releases 15 and 16. Specifically, user equipment (UE) supporting NTN is considered to have Global Navigation Satellite System (GNSS) capabilities. In NTN systems, 5G base stations (gNBs) or gNB functionality are carried on or transparently relayed by satellites, providing communication coverage over very wide areas that may otherwise be unreachable by cellular networks. Such capabilities could be used to connect Internet of Things (IoT) devices on a global scale or to provide personal communications in remote locations. Summary of the Invention

[0003] In a first aspect of the present disclosure, a first apparatus is provided, the first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, assistance information for a switchover from a source non-terrestrial device to a target non-terrestrial device, the assistance information including an instruction regarding a cell identity change associated with the switchover; and, for a plurality of options for the instruction, cause at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell configuration to be maintained.

[0004] In a second aspect of the present disclosure, a second apparatus is provided, the second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: transmit, to the first apparatus, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; and, for a plurality of instruction options, cause at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell setting to be maintained.

[0005] In a third aspect of the present disclosure, a method is provided, the method including receiving, from a second apparatus, aiding information for a switch from a source non-terrestrial device to a target non-terrestrial device, the aiding information including an indication regarding a cell identity change associated with the switch, and causing at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell configuration to be maintained with respect to a plurality of options for the indication.

[0006] In a fourth aspect of the present disclosure, a method is provided, the method including: transmitting, to a first apparatus, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; and causing at least one of a hybrid automatic repeat request (HARQ) buffer, or a security key for wireless communication, or a cell setting to be maintained with respect to a plurality of options for the instruction.

[0007] In a fifth aspect of the present disclosure, a first apparatus is provided, the first apparatus comprising: means for receiving, from a second apparatus, aiding information for a switch from a source non-terrestrial device to a target non-terrestrial device, the aiding information including an instruction regarding a cell identity change associated with the switch; and means for causing at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell configuration to be maintained with respect to a plurality of options for the instruction.

[0008] In a sixth aspect of the present disclosure, a second apparatus is provided, the second apparatus comprising: means for transmitting, to the first apparatus, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; and means for causing at least one of a hybrid automatic repeat request (HARQ) buffer, or a security key for wireless communication, or a cell setting to be maintained with respect to a plurality of options for the instruction.

[0009] In a seventh aspect of the present disclosure, there is provided a computer readable medium comprising instructions stored on the medium for causing an apparatus to perform at least the method according to the third aspect.

[0010] In an eighth aspect of the present disclosure, there is provided a computer readable medium comprising instructions stored thereon for causing an apparatus to perform at least the method according to the fourth aspect.

[0011] It should be understood that this Summary section is not intended to identify key or important features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent through the following description.

[0012] Several exemplary embodiments will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 illustrates an exemplary communication environment in which exemplary embodiments of the present disclosure may be implemented. [Figure 2] 1 is a signaling chart of transitioning to another cell without handover in an NTN, in which exemplary embodiments of the present disclosure can be implemented. [Figure 3] 1 is a flowchart of a method for transitioning to another cell without handover in an NTN, according to some example embodiments of the present disclosure. [Figure 4] 1 is a flowchart of a method implemented in a first device according to some exemplary embodiments of the present disclosure. [Figure 5] 10 is a flowchart of a method implemented in a second device according to some exemplary embodiments of the present disclosure. [Figure 6] FIG. 1 is a simplified block diagram of a device suitable for practicing exemplary embodiments of the present disclosure. [Figure 7] 1 is a block diagram of an exemplary computer-readable medium according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Throughout the drawings, the same or similar reference numbers represent the same or similar elements.

[0015] The principles of the present disclosure will now be described with reference to several exemplary embodiments. It should be understood that these embodiments are set forth for illustrative purposes only, and are intended to assist those skilled in the art in understanding and practicing the present disclosure, without implying any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various ways other than those described below.

[0016] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0017] References in this disclosure to "one embodiment," "one embodiment," "one exemplary embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments need include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is believed to be within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0018] As used herein, terms such as "first," "second," and the like may be used before nouns to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another and do not limit the order of the nouns. For example, a first element could be referred to as a second element, and similarly, a second element could be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0019] As used herein, "at least one of: " and "at least one of " and similar phrases where a list of two or more elements is joined by "and" or "or" mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0020] As used herein, unless explicitly stated, performing a step "in response to A" does not indicate that the step is performed immediately after the occurrence of "A," and may include one or more intervening steps.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "has," "having," "includes," and / or "including," as used herein, indicate the presence of stated features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0022] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) Circuit implementation in hardware only (e.g., implementation in analog and / or digital circuitry only) (b) A combination of hardware circuitry and software, such as (where applicable): (i) a combination of analog and / or digital hardware circuitry and software / firmware; (ii) Any portion of a software-enabled hardware processor (including a digital signal processor), software, and memory that work together to cause a device, such as a mobile phone or server, to perform various functions. (c) Hardware circuitry and / or processors, e.g., microprocessors or portions of microprocessors, that require software (e.g., firmware) to operate, but which may not be present if software is not necessary for operation.

[0023] This definition of circuit applies to all uses of the term in this application, including any claims. As a further example, as used in this application, the term circuit also covers implementations of a hardware circuit or processor(s) only, or of a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuit also covers, for example, baseband or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices, if applicable to certain claim elements.

[0024] As used herein, the term "communications network" refers to a network conforming to any suitable communications standard, such as, for example, New Radio (NR), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrow Band Internet of Things (NB-IoT), etc. Furthermore, communications between terminal devices and network devices within a communications network may be performed according to any suitable generation of communications protocol, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), sixth generation (6G) communications protocols, and / or any other protocols now known or developed in the future. Embodiments of the present disclosure may be applied to various communications systems. Given the rapid development of communications, there will naturally be future types of communications technologies and systems in which the present disclosure may be embodied, which should not be considered to limit the scope of the present disclosure to only the aforementioned systems.

[0025] As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses and receives service from the network. Depending on the terminology and technology applied, a network device may refer to a base station (BS) or access point (AP), e.g., a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), an NR NB (also referred to as a gNB), a remote radio unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, an integrated access and backhaul (IAB) node, a low-power node (e.g., femto, pico, non-terrestrial network (NTN) or non-ground network device (e.g., satellite network device, low earth orbit (LEO) satellite, geosynchronous earth orbit (GEO) satellite, airborne network device, etc.). In some exemplary embodiments, a radio access network (RAN) split architecture comprises a centralized unit (CU) and one or more distributed units (DUs).

[0026] As used herein, the term "non-terrestrial network (NTN)" may refer to a network that includes non-terrestrial airborne objects. For example, an NTN network may include a satellite communications network, a high altitude platform system (HAPS), and / or an air-to-ground network. The term "NTN device" may refer to a network device that participates in an NTN. For example, an NTN device may be a satellite that may host a radio access network (RAN) node.

[0027] The term "terminal device" refers to any end device that may be capable of wireless communication. By way of example and not limitation, a terminal device may also be called a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, voice-over-IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback equipment, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, and the like. A terminal device may also correspond to a Mobile Termination (MT) portion of an IAB node (e.g., a relay node). In the following description, the terms "terminal device," "communications device," "terminal," "user equipment," and "UE" may be used interchangeably.

[0028] As used herein, the terms “resource,” “transmission resource,” “resource block,” “physical resource block” (PRB), “uplink resource,” or “downlink resource” may refer to any resource for performing communications, such as communications between a terminal device and a network device, such as a time-domain resource, a frequency-domain resource, a spatial-domain resource, a code-domain resource, or any other combination of time, frequency, space, and / or code-domain resources that enable communications. Hereinafter, unless explicitly stated, resources in both the frequency and time domains are used as examples of transmission resources to describe some exemplary embodiments of the present disclosure. It should be noted that the exemplary embodiments of the present disclosure are equally applicable to other resources in other domains.

[0029] As used herein, the term "hybrid automatic repeat request (HARQ)" may refer to a combination of fast forward error correction (FEC) and automatic repeat request (ARQ) error control implemented to correct erroneous packets coming from the physical layer. The term "HARQ process" may refer to a stop-and-wait process used to transmit data. Each HARQ process has an independent HARQ buffer. As used herein, the term "flushing a buffer" may refer to a mechanism for deleting data stored in a buffer. As used herein, the term "changing a security key" may refer to a mechanism for updating security information for a communication.

[0030] As used herein, the term "radio link control (RLC)" may refer to the Layer 2 protocol used in the air interface. The RLC layer can provide a sufficiently reliable transport service for selected transmissions. As used herein, the term "packet data convergence protocol (PDCP)" may refer to a layer between the upper radio resource control (RRC) and lower radio link control (RLC) in the control protocol stack. The PDCP layer provides services to the upper RRC or service data adaptation protocol (SDAP) layers and receives services and inputs from the RLC layer, medium access control (MAC) layer, and physical (PHY) layer. As used herein, the term "switching" or "satellite switching" may refer to a mechanism in which the UE is not disconnected, the NTN device through which data is transmitted is switched, and the UE resynchronizes with the NTN device.

[0031] As used herein, the term "physical cell identity (PCI)" may refer to identity information that may be included in a system information block (SIB) and that may be derived after decoding primary synchronization signal / secondary synchronization signal (PSS / SSS) signals, helping a UE identify and distinguish neighboring cells at the physical layer.

[0032] As mentioned above, the feasibility of supporting non-terrestrial networks using the 5G NR standard has been studied. Various types of satellite orbits have been considered for NR access, including low Earth orbit (LEO) satellites at altitudes between 500 and 1500 km. LEO is considered the most relevant case. During the study item, a typical beam footprint size of a LEO satellite was assumed to be between 100 and 1000 km in radius.

[0033] Some solutions have agreed on a permanent physical cell identity (PCI) mobility mechanism to reduce signaling overhead and simplify UE radio resource control (RRC) procedures. Specifically, because the (terrestrial) serving gNB remains unchanged after a satellite switch, the cell configuration can be retained without changing the PCI, frequency, and other cell configuration parameters (e.g., servingCellconfigCommon). In this case, the satellite switch is nearly transparent to the UE, and there is no need to perform L3 mobility (i.e., handover procedures). The conditions for this mechanism to work include the network (NW) instructing the UE when and how to perform DL and UL synchronization after a satellite switch, or allowing an interruption gap for the UE to detect and adapt to the new timing. For example, this mechanism can be applied to scenarios where NTN cells can be deployed as quasi-Earth fixed cells (EFCs). This mechanism can also be applied to earth moving cells. The network needs to have a way to avoid radio link failure (RLF) during this interruption gap (i.e., from the time the "old" cell disappears until the "new" cell takes over). Furthermore, Release 18 places emphasis on a transparent architecture, where the simplest case is when the cells are served by the same gNB, i.e., the same cell with a fixed PCI is served by the same gNB, so only the satellite node changes. However, some terminal devices (e.g., Release 17 devices) do not support the fixed PCI mobility mechanism. Therefore, a solution is needed to move to another cell without handover in non-terrestrial networks (NTN).

[0034] According to an exemplary embodiment, a first device receives NTN device assistance information from a second device. The assistance information indicates at least a cell identity change associated with the switch. The first device skips flushing a buffer, updating a security key, and updating a cell setting in response to a plurality of options of the instruction. In this manner, a cell switch without a handover can be achieved.

[0035] FIG. 1 illustrates an exemplary communication network 100 in which embodiments of the present disclosure may be implemented. As shown in FIG. 1, communication network 100 may include a first device 110. Communication network 100 may further include a second device 120. Additionally, communication network 100 may also include a first NTN device 130-1 and a second NTN device 130-2. For purposes of explanation only, first NTN device 130-1 may be described as a source NTN device, and second NTN device 130-2 may be described as a target NTN device. In some scenarios, first NTN device 130-1 or second NTN device 130-2 may be hosted on a satellite.

[0036] In some demonstrative embodiments, when the first device 110 is a terminal device and the second device 120 is a network device, the link from the second device 120 to the first device 110 is called a downlink (DL), and the link from the first device 110 to the second device 120 is called an uplink (UL). In the DL, the second device 120 is a transmit (TX) device (or transmitter), and the first device 110 is a receive (RX) device (or receiver). In the UL, the first device 110 is a TX device (or transmitter), and the second device 120 is a RX device (or receiver).

[0037] It should be understood that the number of network devices and terminal devices shown in Figure 1 is for illustrative purposes and is not meant to be limiting. Communications network 100 may include any suitable number of network devices and terminal devices.

[0038] Communications in communication environment 100 may be conducted according to any suitable communications protocol, including, but not limited to, cellular communications protocols such as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), fifth generation (5G), sixth generation (6G) referring to narrow band internet of things (NB-IoT) and enhanced machine type communication (eMTC), wireless local network communications protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocols now known or developed in the future. Further, the communications may utilize any suitable wireless communications technology, including, but not limited to, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplexing (FDD), time division duplexing (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other technology now known or developed in the future.

[0039] In some example solutions, satellite switching in which the PCI is kept unchanged in a transparency-based EFC deployment can be applied to communication network 100. For example, stationary first device 110 is served by first NTN device 130-1 (i.e., cell 101). As first NTN device 130-1 moves away from first device 110 and second NTN device 130-2 approaches, second device 120, which is routing its serving cell through first NTN device 130-1, can indicate when first NTN device 130-1 is switched off, when second NTN device 130-2 becomes available, and how to perform resynchronization to the new cell.

[0040] After the second NTN device 130-2 takes over (i.e., serving the cell 102), the first device 110 may perform DL / UL synchronization operations and resume TX / RX. In this case, the first device 110 may retain its cell configuration because it does not change serving gNBs despite being served by a new NTN device (i.e., the second NTN device 130-2). In some demonstrative embodiments, the first NTN device 130-1 and the second NTN device 130-2 may be configured with the same PCI, the same UE context, and the same protocol stack (including synchronization signal block (SSB) generation, encoding / decoding, modulation / demodulation, the same control resource set (CORESET) configuration, and switch routing). Furthermore, from the UE's perspective, the first NTN device 130-1 and the second NTN device 130-2 may introduce different frequency (i.e., Doppler) and timing drift.

[0041] Satellite switching can be classified into two further scenarios: i) hard satellite switching and ii) soft satellite switching. The latter considers the specific cell overlap between the NTN cells emitted by the first NTN device 130-1 and the second NTN device 130-2, while the former does not consider the temporal coverage overlap between the old cell (i.e., cell 101) and the new cell (i.e., 102). In the case of soft satellite switching, it can be assumed that the first NTN device 130-1 and the second NTN device 130-2 simultaneously transmit SSBs (PCIs may be the same, but time / frequency offsets may be different), which allows the first device 110 to smoothly switch to the new (arriving) satellite.

[0042] In some solutions, for quasi-terrestrial fixed cells, satellite switching without PCI change (no L3 mobility required) may be supported for hard satellite switching on the same SSB frequency and the same gNB (no key change). Furthermore, in a hard switching unchanged PCI scenario (i.e., no handover), the first device 110 may need to know when the first device bb110 attempts to resynchronize with the second NTN device 130-2.

[0043] Exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

[0044]

[0023] Reference is now made to Figure 2, which illustrates a signaling chart 200 for communication according to some exemplary embodiments of the present disclosure. As shown in Figure 2, the signaling chart 200 involves a first device 110, a second device 120, a first NTN device 130-1, and a second NTN device 130-2. For ease of explanation, reference is made to Figure 1 to explain the signaling chart 200. As an example, the first NTN device 120-1 may be a source NTN device, and the second NTN device 120-2 may be a target NTN device.

[0045] The second device 120 transmits (2010) to the first device 110 assistance information for switching from the source NTN device (i.e., the first NTN device 130-1) to the target NTN device (i.e., the second NTN device 130-2). In other words, the first device 110 receives the assistance information from the second device 120. The assistance information may be transmitted via RRC signaling. Note that the assistance information may be transmitted via any appropriate signaling. As an example, the first device 110 is currently connected to the first NTN device 130-1 and switches from the first NTN device 130-1 to the second NTN device 130-2. In some exemplary embodiments, the assistance information may be transmitted before the service provided by the first NTN device 130-1 is terminated. In some other exemplary embodiments, the second device 120 may also provide a gap period for the switch. Alternatively, the second device 120 may provide the start of a cell (i.e., cell 102) provided by the second NTN device 130-2.

[0046] The auxiliary information includes an indication regarding a cell identity change associated with the switch. In some exemplary embodiments, this indication may be ignored by Release 17 UEs. In some embodiments, the cell identity may refer to a physical cell identity. Alternatively, the cell identity may refer to cell-specific information in SIB1, which is used to uniquely identify the cell within the network.

[0047] In some exemplary embodiments, the indication may include a switch with cell identity change. For example, the auxiliary information may indicate a satellite with a PCI change where the cell served after the satellite switch has a different PCI, and the PCI is served For example, the cell 102 provided by the second NTN device 130-2 after the switch may have a different PCI than the cell 101 provided by the first NTN device 130-1 before the switch.

[0048] Alternatively, the instruction may include a switch without a cell identity change. For example, the auxiliary information may indicate a satellite without a PCI change, where the cell served after the satellite switch has the same PCI. The PCI may or may not be provided with the auxiliary information.

[0049] In some other embodiments, the indication may include a switch with a virtual cell identity change. For example, the auxiliary information may indicate a satellite with a virtual PCI change. In this case, the PCI of cell 102 may be broadcast with the new cell change. Additionally, an offset or indication to change the PCI calculation may be provided to the first device 110 (which is a Release 18 UE). This allows the first device to continue using the same PCI. Table 1 below shows example information elements (IEs) of the indication. Note that Table 1 is merely an example and not a limitation. In some exemplary embodiments, one of the IEs may be configured in the first device 110, and each IE may provide a list of configuration actions, as described below.

[0050] Table 1 [Table 1]

[0051] The first device 110 may retain at least one of a HARQ buffer, a security key for wireless communication, or a cell configuration in response to a plurality of options for the instruction. For example, the first device 110 may skip one or more of flushing the HARQ buffer, updating the security key, and updating the cell configuration. In some exemplary embodiments, the first device 110 may retain one or more buffers (2020). By way of example, the first device 110 may retain one or more of a HARQ buffer, an RLC buffer, a PDCP buffer, or an SDAP buffer. The first device 110 may retain at least one of a control plane configuration and a user plane configuration. In some exemplary embodiments, the first device 110 may also retain one or more security keys for wireless communication (2030). The first device 110 may also retain a cell configuration (2031). For example, the cell configuration may include one or more of measurement configuration, cell information (e.g., band, frequency, SSB location, random access channel (RACH) configuration, split bearer configuration, etc.), carrier aggregation configuration. Advantageously, buffers are not flushed even when the PCI may change, thus avoiding wasting resources.

[0052] The first device 110 may set the PCI of the cell 102 (2040). In some demonstrative embodiments, if the first device 110 determines that the instruction indicates a switch involving a cell identity change, the first device 110 may obtain a target physical cell identity associated with the second NTN device 130-2 from the auxiliary information. In this case, the first device 110 may set the physical cell identity of the serving cell to the target physical cell identity. That is, the cell 102 may have a different PCI than the cell 101. The first device 110 may maintain at least one of a HARQ buffer, a security key, or a cell configuration. In one embodiment, both a HARQ buffer and a security key are maintained. The maintained security keys include the following security keys: K gNB、 K RRCint, K. RRCenc , K. UPint , K. Upenc In general, any key unique to the PCI may be held.

[0053] Alternatively, if the first device 110 determines that the instruction indicates a switch without a physical cell identity change, the first device 110 may retain the physical cell identity of the serving cell unchanged. For example, cell 102 may have the same PCI as cell 101. The first device 110 may retain at least one of a HARQ buffer, a security key, or a cell configuration.

[0054] In some other embodiments, if the first device 110 determines that the instruction indicates a switch involving a virtual cell identity change, the first device 110 may retain a source cell identification associated with the first NTN device 130-1 and a target cell identification associated with the second NTN device 130-2. For example, the target cell identification may be broadcast. The first device 110 may continue to use the source cell identification based on an offset or an instruction to change the PCI calculation. The first device 110 may retain at least one of a HARQ buffer, a security key, or a cell configuration.

[0055] In some demonstrative embodiments, the first device 110 may perform resynchronization with the second NTN device 130-2 (2050). For example, the first device 110 may resynchronize at the start of the new cell, cell 102. Alternatively, or additionally, the first device 110 may modify at least one measurement filter upon switching (2060). For example, the first device 110 may reset at least one measurement filter.

[0056] In some exemplary embodiments, the aiding information may include a reference time for which the aiding information is valid. For example, the aiding information may include an epoch time that occurs before the end of the switching gap period. In this manner, the first device 110 may prepare ephemeris information for the cell 102 before switching. Alternatively, or additionally, the aiding information may include ephemeris information for the second NTN device 130-2. In some other embodiments, the aiding information may include a common delay associated with the second NTN device 130-2.

[0057] The second device 120 may skip flushing buffers, updating security keys, and / or updating cell settings for multiple options of the instruction. In some exemplary embodiments, the second device 110 120 maintains one or more buffers (2025). By way of example, the second device 120 may maintain one or more of a HARQ buffer, an RLC buffer, a PDCP buffer, or an SDAP buffer. The second device 120 may maintain at least one of a control plane setting and a user plane setting. In some exemplary embodiments, the second device 120 may also maintain one or more security keys (2035). In one exemplary embodiment, the first device 110 may maintain information that may change for handover. Advantageously, buffers are not flushed even if the PCI may change, thereby avoiding wasted resources.

[0058] The second device 120 may set (2040) the PCI of the cell 102. For example, the second device 120 may change the PCI of the cell 101 to the PCI of the cell 102 during the gap period for switching.

[0059] In some demonstrative embodiments, if the instruction indicates a switch involving a cell identity change, second device 120 may obtain a target cell identity associated with second NTN device 130-2 from the auxiliary information. In this case, second device 120 may set the physical cell identity of the serving cell to the target physical cell identity. That is, cell 102 may have a different identity than cell 101. Second device 120 may maintain at least one of a HARQ buffer, a security key, or a cell configuration.

[0060] Alternatively, if the instruction indicates a switch without a cell identity change, the second device 120 may retain the physical cell identity of the serving cell unchanged. For example, cell 102 may have the same PCI as cell 101. The second device 120 may retain at least one of a HARQ buffer, a security key, or a cell configuration.

[0061] In some other embodiments, if the instruction indicates a switch involving a virtual physical cell identification change, the second device 120 may retain a source cell identification associated with the first NTN device 130-1 and a target cell identification associated with the second NTN device 130-2. For example, the target cell identification may be broadcast. The second device 120 may continue to use the source cell identification based on an offset or an instruction to change the PCI calculation. The second device 120 may retain at least one of a HARQ buffer, a security key, or a cell configuration.

[0062] In some demonstrative embodiments, the second device 120 may maintain at least one of the following states: a physical (PHY) entity state, a MAC entity state, an RLC entity state, a PDCP entity state, or an RRC entity state (2045). For example, the states of the PHY, MAC, RLC, PDCDP, and RRC entities may be maintained to the extent possible.

[0063] The second device 120 may transmit cell information of cell 102 via the second NTN device 130-2 (2070). For example, the cell information may be different or the same as the cell information of cell 101. As an example, the second device 120 may transmit an SSB via the second NTN device 130-2. In some demonstrative embodiments, the second device 120 may transmit a demodulation reference signal via the second NTN device 130-2. Alternatively, or additionally, the second device 120 may transmit a channel state information reference signal via the second NTN device 130-2. Note that the order of steps 2020, 2025, 2030, 2035, 2040, 2045, 2050, 2069, and 2070 shown in FIG. 2 is merely an example and not a limitation. These steps may be performed in any suitable order.

[0064] 3 shows a flowchart of a method 300 according to an exemplary embodiment of the present disclosure. As shown in FIG. 3, the first device 110 may determine the type of switching based on the auxiliary information.

[0065] In some demonstrative embodiments, if the aiding information indicates a satellite with a PCI change, the first device 110 may set the PCI to the new PCI (i.e., the changed PCI). The first device 110 may resynchronize to epoch time using the satellite information of the second NTN device 130-2. The first device 110 may maintain buffers such as HARQ, RLC, and PDCP. The first device 110 may maintain security keys for communication with the second device 120. The first device 110 may reset or modify measurement filters.

[0066] In some other exemplary embodiments, if the aiding information indicates a satellite without a PCI change, the first device 110 may retain the PCI (i.e., the unmodified PCI). The first device 110 may resynchronize to epoch time using the satellite information of the second NTN device 130-2. The first device 110 may retain buffers such as HARQ, RLC, and PDCP. The first device 110 may retain security keys for communication with the second device 120. The first device 110 may reset or modify a measurement filter.

[0067] Alternatively, if the auxiliary information indicates a satellite with a virtual PCI change, the first device 110 may maintain two PCIs. For example, one PCI may match one of the new cells (i.e., cell 102), and the virtual PCI may be the same as cell 101. The first device 110 may resynchronize to epoch time using the satellite information of the second NTN device 130-2. The first device 110 may maintain buffers such as HARQ, RLC, and PDCP. The first device 110 may maintain security keys for communication with the second device 120. The first device 110 may reset or modify its measurement filters.

[0068] According to the above embodiment, the UE behavior is not defined with regard to HARQ buffers, measurement filters, scheduling information, handling of serving cell information after t-Service, etc. Furthermore, a Release 17 UE can differentiate between cells and therefore can also stay in a cell where handover without PCI change is used.

[0069] 4 illustrates a flowchart of an example method 400 implemented in an apparatus according to some example embodiments of the present disclosure. For ease of explanation, the method 400 will be described from the perspective of the first device 110 of FIG.

[0070] In block 410, the first device 110 receives aiding information for switching from a source non-terrestrial device to a target non-terrestrial device from the second device 120. The aiding information indicates an instruction regarding a cell identity change associated with the switch.

[0071] In block 420, the first device 110 causes at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell configuration to be maintained for the plurality of options of instructions.

[0072] In some exemplary embodiments, the indication regarding the cell identity change includes one of a switch with a physical cell identity change, a switch without a physical cell identity change, or a switch with a virtual physical cell identity change.

[0073] In some demonstrative embodiments, the method 400 further includes determining that the instruction indicates a switch involving a physical cell identity change, obtaining a target physical cell identity associated with the target non-terrestrial device from the auxiliary information, changing the physical cell identity of the serving cell to the target physical cell identity, and retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0074] In some demonstrative embodiments, the method 400 further includes determining that the indication indicates a switch without a physical cell identity change, retaining the physical cell identity of the serving cell unchanged, and retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0075] In some demonstrative embodiments, the method 400 further includes determining that the indication indicates a switchover with a virtual physical cell identity change, retaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device, and retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0076] In some example embodiments, the method 400 further includes maintaining at least one of a control plane configuration and a user plane configuration.

[0077] In some exemplary embodiments, the method 400 further includes performing a resynchronization with the target non-terrestrial device.

[0078] In some exemplary embodiments, the aiding information further includes at least one of a reference time for which the aiding information is valid, ephemeris information of the target non-terrestrial device, or a general delay associated with the target non-terrestrial device.

[0079] 5 illustrates a flowchart of an example method 500 implemented in a second device according to some example embodiments of the present disclosure. For ease of explanation, the method 500 will be described from the perspective of the second device 120 of FIG.

[0080] In block 510, the second device 120 transmits aiding information for switching from the source non-terrestrial device to the target non-terrestrial device to the first device 110. The aiding information includes instructions regarding cell identity changes associated with the switch.

[0081] In block 520, the second device 120 causes at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell configuration to be maintained for the plurality of options of instructions.

[0082] In some exemplary embodiments, the indication regarding the cell identity change includes one of a switch with a physical cell identity change, a switch without a physical cell identity change, or a switch with a virtual physical cell identity change.

[0083] In some exemplary embodiments, a switch involving a virtual physical cell identity change indicates keeping the physical cell identity and the physical cell identity unchanged.

[0084] In some demonstrative embodiments, the method 500 further includes determining that the indication indicates a switch involving a physical cell identity change, changing the physical cell identity of the serving cell to a target physical cell identity associated with the target non-terrestrial device, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0085] In some demonstrative embodiments, the method 500 further includes determining that the indication indicates a switch without a physical cell identity change, retaining the physical cell identity of the serving cell unchanged, and retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0086] In some demonstrative embodiments, the method 500 further includes determining that the indication indicates a switchover with a virtual physical cell identity change, retaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device, and retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0087] In some example embodiments, the method 500 further includes maintaining at least one of a control plane configuration and a user plane configuration.

[0088] In some demonstrative embodiments, the method 500 further includes maintaining at least one of the following states: a physical entity state, a medium access control entity state, a radio link control entity state, a packet data convergence protocol entity state, or a radio resource control entity state.

[0089] In some exemplary embodiments, the aiding information further includes at least one of a reference time for which the aiding information is valid, ephemeris information of the target non-terrestrial device, or a general delay associated with the target non-terrestrial device.

[0090] In some demonstrative embodiments, a first apparatus capable of performing any of the methods 400 (e.g., the first device 110 of FIG. 1 ) may comprise means for performing each operation of the method 400. The means may be embodied in any suitable form. For example, the means may be embodied in a circuit or a software module. The first apparatus may be embodied as or included in the first device 110 of FIG. 1 .

[0091] In some exemplary embodiments, the first apparatus comprises means for receiving from the second apparatus auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identification information change associated with the switch; and means for causing at least one of a hybrid automatic repeat request (HARQ) buffer, a security key for wireless communication, or a cell setting to be maintained with respect to a plurality of options for the instruction.

[0092] In some exemplary embodiments, the indication regarding the cell identity change includes one of a switch with a physical cell identity change, a switch without a physical cell identity change, or a switch with a virtual physical cell identity change.

[0093] In some demonstrative embodiments, the first apparatus further comprises means for determining that the instruction indicates a switch involving a physical cell identity change, means for obtaining a target physical cell identity associated with the target non-terrestrial device from the auxiliary information, means for changing the physical cell identity of the serving cell to the target physical cell identity, and means for maintaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0094] In some exemplary embodiments, the first apparatus further comprises means for determining that the indication indicates a switch without a physical cell identity change, means for retaining the physical cell identity of the serving cell unchanged, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0095] In some demonstrative embodiments, the first apparatus further comprises means for determining that the indication indicates a switchover involving a virtual physical cell identity change, means for retaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0096] In some exemplary embodiments, the first apparatus further comprises means for maintaining at least one of a control plane configuration and a user plane configuration.

[0097] In some exemplary embodiments, the first apparatus further comprises means for performing a resynchronization with the target non-terrestrial device.

[0098] In some exemplary embodiments, the aiding information further includes at least one of a reference time for which the aiding information is valid, ephemeris information of the target non-terrestrial device, or a general delay associated with the target non-terrestrial device.

[0099] In some exemplary embodiments, the first device comprises a terminal device and the second device comprises a network device.

[0100] In some exemplary embodiments, the first apparatus further comprises means for performing method 400 or other operations in some exemplary embodiments of first device 110. In some exemplary embodiments, the means comprises at least one processor and at least one memory that stores instructions that, when executed by the at least one processor, cause execution of the first apparatus.

[0101] In some demonstrative embodiments, a second apparatus capable of performing any of the methods 500 (e.g., the second device 120 of FIG. 1 ) may comprise means for performing each operation of the method 500. The means may be embodied in any suitable form. For example, the means may be embodied in a circuit or a software module. The second apparatus may be embodied as or included in the second device 120 of FIG. 1 .

[0102] In some exemplary embodiments, the second apparatus comprises means for transmitting auxiliary information to the first apparatus for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identification information change associated with the switch; and means for causing at least one of a hybrid automatic repeat request (HARQ) buffer, or a security key for wireless communication, or a cell setting to be maintained with respect to a plurality of instruction options.

[0103] In some exemplary embodiments, the indication regarding the cell identity change includes one of a switch with a physical cell identity change, a switch without a physical cell identity change, or a switch with a virtual physical cell identity change.

[0104] In some exemplary embodiments, a switch involving a virtual physical cell identity change indicates keeping the physical cell identity and the physical cell identity unchanged.

[0105] In some demonstrative embodiments, the second apparatus further comprises means for determining that the indication indicates a switch involving a physical cell identity change, means for changing the physical cell identity of the serving cell to a target physical cell identity associated with the target non-terrestrial device, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0106] In some exemplary embodiments, the second apparatus further comprises means for determining that the indication indicates a switch without a physical cell identity change, means for retaining the physical cell identity of the serving cell unchanged, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0107] In some demonstrative embodiments, the second apparatus further comprises means for determining that the indication indicates a switchover involving a virtual physical cell identity change, means for retaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device, and means for retaining at least one of a HARQ buffer, a security key, or a cell configuration.

[0108] In some exemplary embodiments, the second apparatus further comprises means for maintaining at least one of a control plane configuration and a user plane configuration.

[0109] In some exemplary embodiments, the second apparatus further comprises means for maintaining at least one of the following states: a physical entity state, a medium access control entity state, a radio link control entity state, a packet data convergence protocol entity state, or a radio resource control entity state.

[0110] In some exemplary embodiments, the aiding information further includes at least one of a reference time for which the aiding information is valid, ephemeris information of the target non-terrestrial device, or a general delay associated with the target non-terrestrial device.

[0111] In some exemplary embodiments, the first device comprises a terminal device and the second device comprises a network device.

[0112] In some exemplary embodiments, the second apparatus further comprises means for performing method 500 or other operations in some exemplary embodiments of second device 120. In some exemplary embodiments, the means comprises at least one processor and at least one memory that stores instructions that, when executed by the at least one processor, cause execution of the second apparatus.

[0113] 6 is a simplified block diagram of a device 600 suitable for implementing an exemplary embodiment of the present disclosure. Device 600 may be provided to implement a communications device such as first device 110 or second device 120 shown in FIG. 1. As shown, device 600 includes one or more processors 610, one or more memories 620 coupled to processors 610, and one or more communications modules 640 coupled to processors 610.

[0114] The communications module 640 is for two-way communication. The communications module 640 has one or more communications interfaces to facilitate communication with one or more other modules or devices. The communications interfaces may represent any interface necessary for communication with other network elements. In some demonstrative embodiments, the communications module 640 may include at least one antenna.

[0115] The processor 610 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The device 600 may have multiple processors, such as application-specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0116] The memory 620 may include one or more nonvolatile memories and one or more volatile memories. Examples of nonvolatile memory include, but are not limited to, read-only memory (ROM) 624, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), optical disks, laser disks, and other magnetic and / or optical storage. Examples of volatile memory include, but are not limited to, random access memory (RAM) 622 and other volatile memory that does not persist during power-off periods.

[0117] The computer program 630 includes computer-executable instructions that are executed by the associated processor 610. The instructions of the program 630 may include instructions for performing the operations / acts of some exemplary embodiments of the present disclosure. The program 630 may be stored in a memory, such as the ROM 624. The processor 610 may perform any appropriate actions and processes by loading the program 630 into the RAM 622.

[0118] An exemplary embodiment of the present disclosure may be implemented by a program 630, such that the device 600 may execute any of the processes of the present disclosure described with reference to Figures 2 to 5. An exemplary embodiment of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0119] In some exemplary embodiments, the program 630 may be tangibly contained in a computer-readable medium, which may be contained within the device 600 (e.g., in memory 620) or other storage device accessible by the device 600. The device 600 may load the program 630 from the computer-readable medium into RAM 622 and execute it. In some exemplary embodiments, the computer-readable medium may include any type of non-transitory storage medium, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. The term "non-transitory," as used herein, is not a limitation on the permanence of the data storage (e.g., RAM vs. ROM), but rather a limitation of the medium itself (i.e., tangible rather than a signal).

[0120] 7 shows an example of a computer readable medium 700, which may be in the form of a CD, DVD, or other optical storage disc. The computer readable medium 700 has the program 630 stored thereon.

[0121] In general, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. While various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using other graphical representations, it should be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented in, by way of non-limiting example, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller, or other computing device, or combinations thereof.

[0122] Some exemplary embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer-readable medium, such as a non-transitory computer-readable medium. The computer program product includes computer-executable instructions, such as those contained in program modules, that execute on a target physical or virtual processor in a device to perform any of the methods described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or divided among program modules as desired in various embodiments. The machine-executable instructions of a program module may be executed in a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

[0123] Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. The program code may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, so that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be performed. The program code may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0124] In the context of the present disclosure, computer program code or associated data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0125] The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More specific examples of the computer-readable storage medium include an electrical connection using one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0126] Furthermore, while operations are shown in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown, sequentially, or that all of the illustrated operations be performed, to achieve desired results. In certain situations, multitasking and parallel processing may be advantageous. Similarly, while the above description includes several specific implementation details, these should not be construed as limiting the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Unless expressly stated, certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, unless expressly stated, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0127] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it is to be understood that the present disclosure, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. at least one processor; at least one memory for storing instructions; wherein the instructions, when executed by the at least one processor, cause the first device to: receiving, from a second apparatus, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; With respect to the multiple options of the instructions, Hybrid Automatic Repeat Request (HARQ) buffer; A security key for wireless communication, or Cell Settings and ensuring that at least one of A first device that executes the above.

2. The instruction regarding the cell identity change may include: Switching with physical cell identity change, Switching without changing the physical cell identity, or Switching with change of virtual physical cell identification information The first device of claim 1 , comprising one of:

3. The first device is determining that the instruction indicates the switch involving a change in physical cell identity; obtaining target physical cell identification information associated with the target non-terrestrial device from the auxiliary information; changing a physical cell identity of a serving cell to the target physical cell identity; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 3. The first device according to claim 1 or 2, further adapted to perform:

4. The first device is determining that the instruction indicates the switching without changing the physical cell identity; keeping the physical cell identity of the serving cell unchanged; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 3. The first device according to claim 1 or 2, further adapted to perform:

5. The first device is determining that the instruction indicates the switch involving a change in the virtual physical cell identity; maintaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 3. The first device according to claim 1 or 2, further adapted to perform:

6. The first device is Maintaining at least one of a control plane configuration and a user plane configuration The first device according to any one of claims 1 to 5, further adapted to perform:

7. The first device is performing a resynchronization with the target non-terrestrial device; A first device according to any one of claims 1 to 6, adapted to perform:

8. The auxiliary information is a reference time for which the auxiliary information is valid; Ephemeris information of the target non-terrestrial device; or Typical delays associated with target non-terrestrial devices, The first device according to any one of claims 1 to 7, further comprising at least one of:

9. The first device of any one of claims 1 to 8, wherein the first device comprises a terminal device and the second device comprises a network device.

10. at least one processor; at least one memory for storing instructions; wherein the instructions, when executed by the at least one processor, cause the second device to: transmitting, to a first device, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; With respect to the multiple options of the instructions, Hybrid Automatic Repeat Request (HARQ) buffer, or A security key for wireless communication, or Cell Settings and ensuring that at least one of A second device that executes the above.

11. The instruction regarding the cell identity change may include: Switching with physical cell identity change, Switching without changing the physical cell identity, or Switching with change of virtual physical cell identification information The second device of claim 10, comprising one of:

12. The second apparatus of claim 11 , wherein the switching with the virtual physical cell identity change indicates keeping the physical cell identity and the physical cell identity unchanged.

13. The second device is determining that the instruction indicates the switch involving a change in physical cell identity; changing a physical cell identity of a serving cell to a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 12. The second device according to claim 10 or 11, further adapted to perform:

14. The second device is determining that the instruction indicates the switching without changing the physical cell identity; keeping the physical cell identity of the serving cell unchanged; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 12. The second device according to claim 10 or 11, further adapted to perform:

15. The second device is determining that the instruction indicates the switch involving a change in the virtual physical cell identity; maintaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 12. The second device according to claim 10 or 11, further adapted to perform:

16. The second device is Maintaining at least one of a control plane configuration and a user plane configuration A second device according to any one of claims 10 to 15, adapted to perform:

17. The second device is The following conditions: Physical entity state, Medium Access Control Entity State, Radio Link Control Entity State, Packet Data Convergence Protocol Entity State, or Radio Resource Control Entity State To hold at least one of A second device according to any one of claims 10 to 16, adapted to perform:

18. The auxiliary information is a reference time for which the auxiliary information is valid; Ephemeris information of the target non-terrestrial device; or Typical delays associated with target non-terrestrial devices, The second device according to any one of claims 10 to 17, further comprising at least one of:

19. The second device of any one of claims 10 to 18, wherein the first device comprises a terminal device and the second device comprises a network device.

20. receiving, at a first apparatus, from a second apparatus, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; With respect to the multiple options of the instructions, Hybrid Automatic Repeat Request (HARQ) buffer; A security key for wireless communication, or Cell Settings and ensuring that at least one of A method comprising:

21. The instruction regarding the cell identity change may include: Switching with physical cell identity change, Switching without changing the physical cell identity, or Switching with change of virtual physical cell identification information 21. The method of claim 20, comprising one of:

22. The first device determining that the instruction indicates the switch involving a change in physical cell identity; obtaining target physical cell identification information associated with the target non-terrestrial device from the auxiliary information; changing a physical cell identity of a serving cell to the target physical cell identity; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 22. The method of claim 20 or 21, further comprising:

23. The first device determining that the instruction indicates the switching without changing the physical cell identity; keeping the physical cell identity of the serving cell unchanged; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 22. The method of claim 20 or 21, further comprising:

24. The first device determining that the instruction indicates the switch involving a change in the virtual physical cell identity; maintaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 22. The method of claim 20 or 21, further comprising:

25. The first device Maintaining at least one of a control plane configuration and a user plane configuration The method of any one of claims 20 to 24, further comprising:

26. The first device performing a resynchronization with the target non-terrestrial device; The method of any one of claims 20 to 25, further comprising:

27. The auxiliary information is a reference time for which the auxiliary information is valid; Ephemeris information of the target non-terrestrial device; or Typical delays associated with target non-terrestrial devices, The method of any one of claims 20 to 26, further comprising at least one of:

28. The method of any one of claims 20 to 27, wherein the first device comprises a terminal device and the second device comprises a network device.

29. transmitting, at a second device, auxiliary information for a switch from a source non-terrestrial device to a target non-terrestrial device to a first device, the auxiliary information including an instruction regarding a cell identity change associated with the switch; With respect to the multiple options of the instructions, Hybrid Automatic Repeat Request (HARQ) buffer; A security key for wireless communication, or Cell Settings and ensuring that at least one of A method comprising:

30. The instruction regarding the cell identity change may include: Switching with physical cell identity change, Switching without changing the physical cell identity, or Switching with change of virtual physical cell identification information 30. The method of claim 29, comprising one of:

31. 31. The method of claim 30, wherein the switch involving the virtual physical cell identity change indicates keeping physical cell identity and physical cell identity unchanged.

32. The second device determining that the instruction indicates the switch involving a change in physical cell identity; changing a physical cell identity of a serving cell to a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 31. The method of claim 29 or 30, further comprising:

33. The second device determining that the instruction indicates the switching without changing the physical cell identity; keeping the physical cell identity of the serving cell unchanged; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 31. The method of claim 29 or 30, further comprising:

34. The second device determining that the instruction indicates the switch involving a change in the virtual physical cell identity; maintaining a source physical cell identity associated with the source non-terrestrial device and a target physical cell identity associated with the target non-terrestrial device; maintaining the at least one of the HARQ buffer, the security key, or the cell configuration; 31. The method of claim 29 or 30, further comprising:

35. The second device Maintaining at least one of a control plane configuration and a user plane configuration The method of any one of claims 29 to 34, further comprising:

36. The second device The following conditions: Physical entity state, Medium Access Control Entity State, Radio Link Control Entity State, Packet Data Convergence Protocol Entity State, or Radio Resource Control Entity State To hold at least one of The method of any one of claims 29 to 35, further comprising:

37. The auxiliary information is a reference time for which the auxiliary information is valid; Ephemeris information of the target non-terrestrial device; or Typical delays associated with target non-terrestrial devices, The method of any one of claims 29 to 36, further comprising at least one of:

38. The method of any one of claims 29 to 37, wherein the first device comprises a terminal device and the second device comprises a network device.

39. A computer readable medium comprising instructions stored thereon to cause an apparatus to perform at least the method of any one of claims 20 to 38.

Images