Methods and apparatus for l2 reset indication and ta indication for ue measurement in ltm scenarios

Abstract

Embodiments of the present disclosure relate to methods and apparatuses for L2 reset indication and TA indication of UE measurement in LTM scenarios. According to some embodiments of the present disclosure, a first network node can: transmit a request message to a second network node, wherein the request message includes an ID of a first candidate cell and an indication of a request for information related to TA or no reset of UE measurement of the first candidate cell; receive a response message from the second network node in response to the request message; and transmit a configuration to a UE, a third network node, or both based on the response message.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to wireless communication technologies, and more specifically, to handling L2 reset indications and user equipment (UE) measurement timing advance (TA) indications in L1 / L2 triggered mobility (LTM) scenarios. Background Technology

[0002] A wireless communication system may include one or more network communication devices, such as base stations, which can support wireless communication with one or more user communication devices (which may also be referred to as user equipment (UE) or other suitable terms). The wireless communication system can support wireless communication with one or more user communication devices by utilizing the resources of the wireless communication system (e.g., time resources (e.g., symbols, time slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like)). Furthermore, the wireless communication system can support wireless communication across various radio access technologies, including third-generation (3G) radio access technology, fourth-generation (4G) radio access technology, fifth-generation (5G) (also known as New Radio (NR)) radio access technology, and other suitable radio access technologies beyond 5G (e.g., sixth-generation (6G)).

[0003] In wireless communication systems, base stations (BS) and users (UEs) can communicate via downlink and uplink channels. In some scenarios, the BS can trigger an LTM procedure to instruct the UE to hand over from its current serving cell to a target cell.

[0004] In LTM scenarios, it is necessary to handle L2 reset (e.g., no L2 reset) indications and TA indications measured by the UE. Summary of the Invention

[0005] The article “a” preceding an element is unrestricted and should be understood to refer to “at least one” or “one or more” of these elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” are interchangeable. As used herein (included in the claims), the word “or” used in a list of items (e.g., a list of items beginning with phrases such as “at least one of…”, “one or more of…”, or “one or both of…”) indicates an inclusive list, such that (e.g.) a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Furthermore, as used herein, the phrase “based on” should not be construed as referring to a closed set of conditions. For example, without departing from the scope of this disclosure, an example step described as “based on condition A” may be based on both condition A and condition B. In other words, as used herein, the phrase “based on” should be interpreted in the same manner as the phrase “at least partially based on.” Furthermore, as used herein (included in the claims), a “group” may comprise one or more elements.

[0006] Some embodiments of this disclosure provide a first network node. The first network node may include: at least one memory; and at least one processor coupled to the at least one memory and configured to cause the first network node to: transmit a request message to a second network node, wherein the request message includes an ID of a first candidate cell and an indication of requesting information related to a TA or no reset of a UE measured in the first candidate cell; receive a response message from the second network node in response to the request message; and transmit configuration to a UE, a third network node, or both based on the response message.

[0007] In some embodiments of this disclosure, the information related to the TA measured by the UE of the first candidate cell may indicate whether the UE is able to obtain the TA of the first candidate cell by performing a UE-based TA measurement when an LTM cell handover procedure from the second cell to the first candidate cell is performed.

[0008] In some embodiments of this disclosure, the response message may indicate a list of cells that includes: at least one cell in which the UE can obtain the TA of the first candidate cell by performing a UE-based TA measurement; or at least one cell in which the UE belongs to the second network node and meets the time alignment error (TAE) requirement.

[0009] In some embodiments of this disclosure, the information related to the absence of a reset in the first candidate cell may indicate whether the UE performs an L2 reset when the UE switches from the second cell to the first candidate cell.

[0010] In some embodiments of this disclosure, the response message may indicate a list of cells including: at least one cell from which the UE does not perform an L2 reset when the UE switches from the at least one cell to the first candidate cell; or at least one cell belonging to the second network node.

[0011] In some embodiments of this disclosure, the second cell may include the UE's serving cell or its LTM configuration that has been provided by the second network node to the first network node as a candidate cell.

[0012] In some embodiments of this disclosure, the cell list may include the second cell.

[0013] In some embodiments of this disclosure, the configuration may indicate one of the following: TA IDs of one or more UE-measured TA IDs of the first candidate cell and UE-measured TA IDs of the UE's serving cell; a candidate cell list, wherein when an LTM cell handover procedure is performed from the serving cell to a corresponding candidate cell in the candidate cell list, the UE can obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurements; the association between the first candidate cell and a second candidate cell, wherein when an LTM cell handover procedure is performed from the second candidate cell to the first candidate cell, the UE can obtain the TA of the first candidate cell by performing UE-based TA measurements; and the association between the UE's serving cell and at least one candidate cell, wherein the serving cell and the at least one candidate cell belong to the same network node and satisfy the TAE requirement.

[0014] In some embodiments of this disclosure, the first network node is associated with the primary cell group (MCG) of the UE or the secondary cell group (SCG) of the UE.

[0015] Some embodiments of this disclosure provide a second network node. The second network node may include: at least one memory; and at least one processor coupled to the at least one memory and configured such that the second network node: receives a request message from a first network node, wherein the request message may include an ID of a first candidate cell and an indication of requesting information related to a TA or no reset of a UE measurement of the first candidate cell; and transmits a response message to the first network node in response to the request message.

[0016] In some embodiments of this disclosure, the information related to the TA measured by the UE of the first candidate cell may indicate whether the UE is able to obtain the TA of the first candidate cell by performing a UE-based TA measurement when performing an LTM cell handover procedure from the second cell to the first candidate cell.

[0017] In some embodiments of this disclosure, the response message may indicate a list of cells that includes: at least one cell in which the UE can obtain the TA of the first candidate cell by performing a UE-based TA measurement; or at least one cell that belongs to the second network node and meets the TAE requirements.

[0018] In some embodiments of this disclosure, the information related to the absence of a reset in the first candidate cell may indicate whether the UE performs an L2 reset when the UE switches from the second cell to the first candidate cell.

[0019] In some embodiments of this disclosure, the response message may indicate a list of cells including: at least one cell from which the UE does not perform an L2 reset when the UE switches from the at least one cell to the first candidate cell; or at least one cell belonging to the second network node.

[0020] In some embodiments of this disclosure, the second cell may include the UE's serving cell or its LTM configuration that has been provided to the first network node by the second network node.

[0021] In some embodiments of this disclosure, the cell list may include the second cell.

[0022] Some embodiments of this disclosure provide a third network node. The third network node may include: at least one memory; and at least one processor coupled to the at least one memory and configured to cause the third network node to: receive configuration from a first network node, wherein the configuration may include information related to TA (Tracking Aspect Ratio) measured by a UE for a first candidate cell; and determine, based on the received configuration, whether to trigger the UE to perform early TA acquisition regarding the first candidate cell.

[0023] In some embodiments of this disclosure, the configuration may indicate one of the following: a TA ID of one or more UE-measured TA cells of the first candidate cell and a UE-measured TA ID of the serving cell of the UE; a candidate cell list, wherein when an LTM cell handover procedure is performed from the serving cell to a corresponding candidate cell in the candidate cell list, the UE is able to obtain the TA of each candidate cell in the candidate cell list by performing a UE-based TA measurement; an association between the first candidate cell and a second candidate cell, wherein when an LTM cell handover procedure is performed from the second candidate cell to the first candidate cell, the UE is able to obtain the TA of the first candidate cell by performing a UE-based TA measurement; and an association between the serving cell of the UE and at least one candidate cell, wherein the serving cell and the at least one candidate cell belong to the same network node and satisfy the TAE requirement.

[0024] Some embodiments of this disclosure provide a UE. The UE may include: at least one memory; and at least one processor coupled to the at least one memory and configured to cause the UE to: receive a reconfiguration message from a network node containing an LTM configuration of one or more candidate cells; and, in response to receiving a handover command to hand over to a second cell or in response to meeting conditions for handover to the second cell, hand over from the UE's serving cell to the second cell and set the UE-measured TA ID of the serving cell or the no-reset ID of the serving cell based on the reconfiguration message.

[0025] In some embodiments of this disclosure, in order to set the TA ID measured by the UE of the serving cell, the at least one processor is configured to cause the UE to perform one or more of the following: in response to receiving the handover command and the second cell being one of the one or more candidate cells, setting the value of the TA ID measured by the UE of the serving cell to the value of the TA ID measured by the UE of the second cell as indicated in the LTM configuration; in response to receiving the handover command and the second cell not being one of the one or more candidate cells, receiving the TA ID measured by the UE of the second cell from the network node and setting the value of the TA ID measured by the UE of the serving cell to the value of the received TA ID measured by the UE of the second cell; and in response to satisfying the condition for handover to the second cell, receiving the TA ID measured by the UE of the second cell from the network node and setting the value of the TA ID measured by the UE of the serving cell to the value of the received TA ID measured by the UE of the second cell.

[0026] In some embodiments of this disclosure, in order to set the no-reset ID of the serving cell, the at least one processor is configured to cause the UE to perform one or more of the following: in response to receiving the handover command and the second cell being one of the one or more candidate cells, setting the value of the no-reset ID of the serving cell to the value of the no-reset ID of the second cell indicated in the LTM configuration; in response to receiving the handover command and the second cell not being one of the one or more candidate cells, receiving the no-reset ID of the second cell from the network node and setting the value of the received no-reset ID of the serving cell to the value of the no-reset ID of the second cell; and in response to satisfying the condition for handover to the second cell, receiving the no-reset ID of the second cell from the network node and setting the value of the no-reset ID of the serving cell to the value of the received no-reset ID of the second cell.

[0027] In some embodiments of this disclosure, in order to receive the TA ID measured by the UE of the second cell or the no-reset ID of the second cell, the at least one processor is configured to cause the UE to receive the TA ID measured by the UE of the second cell or the no-reset ID of the second cell in or before the configuration of the handover command or the conditions for handover to the second cell.

[0028] In some embodiments of this disclosure, the conditions for switching to the second cell are related to Conditional Handover (CHO) or Conditional Primary Auxiliary Cell Change (CPC).

[0029] Some embodiments of this disclosure provide a processor. The processor may include at least one controller coupled to at least one memory and configured to perform methods according to some embodiments of this disclosure.

[0030] Some embodiments of this disclosure provide an apparatus. According to some embodiments of this disclosure, the apparatus may include: at least one non-transitory computer-readable medium storing computer-executable instructions thereon; at least one receiving circuitry system; at least one transmitting circuitry system; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry system, and the at least one transmitting circuitry system, wherein the at least one non-transitory computer-readable medium and the computer-executable instructions are configured to cause the apparatus to perform a method according to some embodiments of this disclosure using the at least one processor. Attached Figure Description

[0031] To illustrate the advantages and features of this disclosure, the description of the disclosure is presented with reference to specific embodiments of the disclosure illustrated in the accompanying drawings. These drawings depict only exemplary embodiments of the disclosure and should therefore not be construed as limiting its scope.

[0032] Figure 1 Illustrated schematic diagrams of wireless communication systems according to some embodiments of the present disclosure;

[0033] Figures 2 to 4 A flowchart illustrating a wireless communication method according to some embodiments of the present disclosure;

[0034] Figures 5 to 7 A flowchart illustrating a wireless communication method performed by a network device (NE) according to some embodiments of the present disclosure;

[0035] Figure 8 A flowchart illustrating a wireless communication method performed by a UE according to some embodiments of this disclosure;

[0036] Figure 9 Examples of UEs according to some embodiments of this disclosure are described;

[0037] Figure 10 Examples of processors according to some embodiments of this disclosure; and

[0038] Figure 11 Examples of NEs according to some embodiments of this disclosure are described. Detailed Implementation

[0039] The detailed description of the accompanying drawings is intended to describe preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functionality may be achieved through different embodiments that are intended to be covered within the spirit and scope of the present disclosure.

[0040] Reference will now be made to some embodiments of this disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architectures and new service scenarios (e.g., 3GPP 5G NR or 6G, 3GPP LTE, etc.). It should be understood that all embodiments in this disclosure are applicable to similar technical problems as network architectures and new service scenarios evolve; furthermore, the terminology cited in this disclosure may change, which should not affect the principles of this disclosure.

[0041] In communication systems, the NE (e.g., BS) can trigger an LTM cell handover procedure to instruct the UE to hand over from its serving cell to a target cell. Solutions are needed to facilitate LTM procedures. For example, solutions are needed to facilitate the indication or determination of TA information measured by the UE in LTM scenarios and the absence of reset information. For example, solutions are needed to handle the coexistence of early TA acquisition and UE-based measurement TA.

[0042] This disclosure provides solutions to address the aforementioned problems. For example, it provides embodiments that facilitate the indication or determination of TA information and no-reset information for UE measurements. For example, it provides embodiments that handle the coexistence of early TA acquisition and UE-based measurement TA.

[0043] Figure 1 A schematic diagram illustrating a wireless communication system 100 according to some embodiments of the present disclosure.

[0044] The wireless communication system 100 may include one or more NEs 102 (e.g., one or more BSs), one or more UEs 104, and a core network (CN) 106. The wireless communication system 100 may support various radio access technologies. In some embodiments, the wireless communication system 100 may be a 4G network, such as an LTE network or an LTE-A network. In some other embodiments, the wireless communication system 100 may be an NR network, such as a 5G network, a 5G-A network, or a 5G Ultra Wideband (5G-UWB) network. In other embodiments, the wireless communication system 100 may be a combination of 4G and 5G networks or other suitable radio access technologies, including IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20. The wireless communication system 100 may support radio access technologies beyond 5G, such as 6G. In addition, the wireless communication system 100 can support technologies such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), or Code Division Multiple Access (CDMA).

[0045] One or more NEs 102 may be distributed throughout a geographic area to form a wireless communication system 100. One or more of the NEs 102 described herein may be, include, or be referred to as a network node, base station, network element, network function, network entity, wireless access network (RAN), NodeB, eNodeB (eNB), next-generation NodeB (gNB), or other suitable terms. In some embodiments of this disclosure, the NE 102 may include a centralized unit (CU) and one or more distributed units (DU). An F1 interface may be established between the DUs and CUs of the NE 102.

[0046] NE 102 and UE 104 can communicate via a communication link that can be wireless or wired. For example, NE 102 and UE 104 can perform wireless communication (e.g., receiving signaling, transmitting signaling) through the Uu interface.

[0047] NE 102 can provide a geographic coverage area for which NE 102 can support services for one or more UEs 104 within the geographic coverage area. For example, NE 102 and UE 104 can support wireless communication of signals associated with services (e.g., voice, video, packet data, messaging, broadcasting, etc.) using one or more radio access technologies. In some embodiments, NE 102 can be mobile, such as a satellite associated with a non-terrestrial network (NTN). In some embodiments, different geographic coverage areas 112 associated with the same or different radio access technologies can overlap, but different geographic coverage areas can be associated with different NEs 102.

[0048] One or more UEs 104 may be distributed throughout the geographic area of ​​the wireless communication system 100. UE 104 may include or be referred to as a remote unit, mobile device, wireless device, remote device, subscriber device, transmitter device, receiver device, or some other suitable term. In some embodiments, UE 104 may be referred to as a unit, station, terminal, or client, and other instances thereof. Alternatively or additionally, UE 104 may be referred to as an Internet of Things (IoT) device, Internet of Everything (IoE) device, or Machine-Type Communication (MTC) device, and other instances thereof.

[0049] UE 104 may be able to support direct wireless communication with other UE 104 via a communication link. For example, UE 104 may support direct wireless communication with another UE 104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link 114 may be referred to as a sidelink. For example, UE 104 may support direct wireless communication with another UE 104 via a PC5 interface.

[0050] Sidelink-based relay functionality may be supported in the wireless communication system 100. For example, a UE 104 supporting sidelink communication can be used as a relay node to extend the coverage of NE 102 (e.g., BS). UEs outside or within the coverage area can communicate with the BS via the relay node (e.g., a relay UE). In some embodiments, a UE acting as a relay between another UE and the BS may be referred to as a UE-to-network (U2N) relay.

[0051] NE 102 may support communication with CN 106 or another NE 102, or both. For example, NE 102 may interface with another NE 102 or CN 106 via one or more backhaul links (e.g., S1, N2, N3, or another network interface). In some implementations, NE 102 may communicate directly with each other. In some other implementations, NE 102 may communicate indirectly with each other (e.g., via CN 106). In some implementations, one or more NE 102 may include sub-components, such as access network entities, which may be instances of Access Node Controllers (ANCs). The ANC may communicate with one or more UE 104s via one or more other access network transmitting entities, which may be referred to as radio headends, smart radio headends, or transmit-receive points (TRPs).

[0052] CN 106 can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. CN 106 can be an evolved packet core (EPC) or a 5G core (5GC), which may include control plane entities (e.g., Mobility Management Entity (MME), Access and Mobility Management Function (AMF)) that manage access and mobility, and user plane entities (e.g., Serving Gateway (S-GW), Packet Data Network (PDN) Gateway (P-GW), or User Plane Function (UPF)) that route packets or interconnects to external networks. In some implementations, the control plane entities may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signaling bearers, etc.) of one or more UEs 104 served by one or more NEs 102 associated with CN106.

[0053] CN 106 can communicate with the packet data network via one or more backhaul links (e.g., via S1, N2, N3, or another network interface). The packet data network may contain an application server. In some implementations, one or more UEs 104 can communicate with the application server. UE 104 can establish a session (e.g., a Protocol Data Unit (PDU) session or the like) with CN 106 via NE 102. CN 106 can use the established session (e.g., an established PDU session) to route traffic (e.g., control information, data, and the like) between UE 104 and the application server. A PDU session can be an instance of a logical connection between UE 104 and CN 106 (e.g., one or more network functions of CN 106).

[0054] In the wireless communication system 100, NE 102 and UE 104 can use the resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, time slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communication). In some embodiments, NE 102 and UE 104 may support different resource structures. For example, NE 102 and UE 104 may support different frame structures. In some embodiments, such as in 4G, NE 102 and UE 104 may support a single frame structure. In some other embodiments, such as in 5G and other suitable radio access technologies, NE 102 and UE 104 may support various frame structures (i.e., multiple frame structures). NE 102 and UE 104 may support various frame structures based on one or more sets of parameters.

[0055] The wireless communication system 100 may support one or more parameter sets, and the parameter sets may include subcarrier spacing and cyclic prefixes. A first parameter set (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a regular cyclic prefix. In some embodiments, the first parameter set (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one time slot per subframe. A second parameter set (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a regular cyclic prefix. A third parameter set (e.g., μ=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a regular cyclic prefix or an extended cyclic prefix. A fourth parameter set (e.g., μ=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a regular cyclic prefix. A fifth parameter set (e.g., μ=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a regular cyclic prefix.

[0056] Time intervals for resources (such as communication resources) can be organized according to frames (also known as radio frames). Each frame may have a duration, for example, 10 milliseconds (ms). In some embodiments, each frame may contain multiple subframes. For example, each frame may contain 10 subframes, and each subframe may have a duration, for example, 1 ms. In some embodiments, each frame may have the same duration. In some embodiments, each subframe of a frame may have the same duration.

[0057] Alternatively or concurrently, the time intervals of resources (e.g., communication resources) can be organized according to time slots. For example, a subframe may contain a certain number (e.g., a certain quantity) of time slots. The number of time slots in each subframe may also depend on one or more parameter sets supported in the wireless communication system 100. For example, the first, second, third, fourth, and fifth parameter sets (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with corresponding subcarrier intervals of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can respectively utilize one time slot per subframe, two time slots per subframe, four time slots per subframe, eight time slots per subframe, and 16 time slots per subframe. Each time slot may contain a certain number (e.g., a certain quantity) of symbols (e.g., Orthogonal Frequency Division Multiplexing (OFDM) symbols). In some embodiments, the number (e.g., quantity) of time slots in a subframe may depend on the parameter set. For a conventional cyclic prefix, a time slot may contain 14 symbols. For an extended cyclic prefix (e.g., applicable to a 60 kHz subcarrier spacing), a time slot may contain 12 symbols. The relationship between the number of symbols per time slot, the number of time slots per subframe, and the number of time slots per frame for the regular and extended cyclic prefixes may depend on the parameter set. It should be understood that references to the first parameter set (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) can be used interchangeably between subframes and time slots.

[0058] In the wireless communication system 100, the electromagnetic (EM) spectrum can be divided into various categories, bands, channels, etc., based on frequency or wavelength. For example, the wireless communication system 100 may support one or more operating frequency bands, such as frequency ranges represented as FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4 (52.6 GHz to 114.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), and FR5 (114.25 GHz to 300 GHz). In some embodiments, NE 102 and UE 104 may perform wireless communication on one or more of the operating frequency bands. In some embodiments, FR1 may be used by NE 102 and UE 104, as well as other equipment or devices, for cellular communication services (e.g., control information, data). In some implementations, FR2 can be used by NE 102 and UE 104, as well as other equipment or devices, for short-range, high data rate capabilities.

[0059] FR1 can be associated with one or more parameter sets (e.g., at least three parameter sets). For example, FR1 can be associated with: a first parameter set (e.g., μ=0) containing a 15 kHz subcarrier spacing; a second parameter set (e.g., μ=1) containing a 30 kHz subcarrier spacing; and a third parameter set (e.g., μ=2) containing a 60 kHz subcarrier spacing. FR2 can be associated with one or more parameter sets (e.g., at least two parameter sets). For example, FR2 can be associated with: a third parameter set (e.g., μ=2) containing a 60 kHz subcarrier spacing; and a fourth parameter set (e.g., μ=3) containing a 120 kHz subcarrier spacing.

[0060] UE 104 may include computing devices such as desktop computers, laptop computers, personal digital assistants (PDAs), tablet computers, smart TVs (e.g., TVs connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), in-vehicle computers, network devices (e.g., routers, switches, and modems), or the like. According to some embodiments of this disclosure, UE 104 may include portable wireless communication devices, smartphones, cellular phones, flip phones, devices with subscriber identification modules, personal computers, selective call receivers, or any other devices capable of transmitting and receiving communication signals on a wireless network. In some embodiments of this disclosure, UE 104 includes wearable devices such as smartwatches, fitness trackers, optical head-mounted displays, or the like. Furthermore, UE 104 may be referred to as a subscriber unit, mobile device, mobile station, user, terminal, mobile terminal, wireless terminal, fixed terminal, subscriber station, user terminal, or device, or described using other terms used in the art. UE 104 may communicate with NE 102 (e.g., BS) via uplink (UL) communication signals. NE 102 can communicate with UE 104 via downlink (DL) communication signals.

[0061] In some embodiments of this disclosure, NE 102 and UE 104 may communicate via licensed spectrum, while in other embodiments, NE 102 and UE 104 may communicate via unlicensed spectrum. This disclosure is not intended to limit implementation to any particular wireless communication system architecture or protocol.

[0062] In some embodiments of this disclosure, the NE (e.g., BS) may trigger an LTM cell handover procedure to instruct the UE to hand over from its serving cell to a target cell. For example, based on an L1 measurement report from the UE, the BS may determine to change the UE's serving cell via a cell handover command. The cell handover command may instruct the BS to provide a previously prepared LTM candidate cell configuration to the UE. The UE may then hand over to the target cell according to the cell handover command. The LTM procedure can be used to reduce mobility latency.

[0063] Embodiments of this disclosure provide technical solutions for facilitating LTM procedures in communication networks. For example, a solution is provided to determine whether a UE can obtain the TA of a candidate cell by performing UE-based TA measurement when performing an LTM cell handover from one cell to a candidate cell. For example, a solution is provided to determine whether a UE should perform an L2 reset when performing an LTM cell handover from one cell to a candidate cell. For example, in some cases, early TA acquisition and UE-based TA measurement in LTM can coexist. For instance, in LTM, a CU can transmit a request for a Random Access Channel (RACH) resource for early TA acquisition to a target DU. The RACH resource for early TA acquisition can be transmitted to the UE and a source DU. The source DU can trigger the UE to transmit a preamble to a candidate DU for early TA acquisition. The candidate DU can receive the preamble and calculate the TA value. The candidate DU can then transmit the TA value and its associated information to the source DU via the CU. For example, the associated information may include a preamble index, Random Access Timing (RO) information (e.g., a Random Access Radio Network Temporary Identifier (RA-RNTI)), and a candidate cell identifier. The source DU can identify the UE based on the information. However, in some cases, the UE can obtain the TA value of a candidate cell by performing UE-based TA measurements. Solutions are provided to handle the coexistence of early TA acquisition and UE-based TA measurements. For example, in some cases, a handover command or the fulfillment of path handover conditions can trigger the UE to handover from its serving cell to another cell configured as a candidate cell. Solutions are provided to handle the UE-measured TA information and no-reset information of the serving cell after this handover or path handover. Further details regarding embodiments of this disclosure will be described below in conjunction with the accompanying drawings.

[0064] Figure 2 A flowchart illustrating an exemplary wireless communication method 200 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 2 The embodiments shown are illustrated below. For example, UE 204 can be used as... Figure 1 UE 104, and network nodes 202 to 208 can be used as Figure 1 The NE 102 shown in the diagram. In some embodiments, network nodes 202 and 208 may be used as the DU of the BS, and network node 206 may be used as the CU of the BS. The BS may be referred to as the "serving BS" of UE 204, and for clarity, is designated as BS #A.

[0065] refer to Figure 2In 211, UE 204 can connect to (or access) BS #A. For example, UE 204 can access the cell of network node 202, which may be referred to as the "serving cell" of UE 204. UE 204 can send measurement reports to BS #A. In some instances, UE 204 can access the network via single connectivity (e.g., via MCG only), and BS #A is associated with UE 204's MCG. In some instances, UE 204 can access the network via dual connectivity (e.g., via MCG and SCG), and BS #A can be associated with either UE 204's MCG or SCG.

[0066] BS #A can be used to initiate the LTM configuration procedure for UE 204. For example, at 213, network node 206 can be used to initiate the LTM configuration procedure for UE 204. For example, network node 206 can be used to configure at least one candidate cell (e.g., cell #A) for UE 204's LTM cell handover, and cell #A can belong to network node 208. Network node 208 can therefore also be referred to as a "candidate network node" or "candidate DU".

[0067] At 215, network node 206 may send a request message to network node 208. In some embodiments, the request message may indicate cell #A. For example, the request message may include the ID of cell #A. In some embodiments, the request message may further include an indication requesting information related to the TA or no reset of the UE measurement for cell #A. In the context of this disclosure, "TA measured by the UE" may also be referred to as "UE-based TA measurement".

[0068] By providing information related to the TA (Transmission Ability) measured by the UE for cell #A, network node 206 can request network node 208 to determine whether UE 204 can obtain the TA of cell #A via UE-based TA measurements when performing an LTM cell handover procedure from another cell (e.g., cell #B) to cell #A. Cell #B can be the serving cell of UE 204 or a ready candidate cell for UE 204. In the context of this disclosure, a ready candidate cell for UE refers to a candidate cell whose LTM configuration has been provided by a candidate network node (e.g., by network node 208 to network node 206). In some embodiments, network node 206 may have transmitted the LTM configuration of the ready candidate cell to UE 204. In response to the request message, network node 208 can provide the association between cell #A and cell #B.

[0069] For example, suppose UE 204's current serving cell is cell #0 and network node 206 has prepared candidate cell #1 associated with network node 208 for LTM. Network node 206 may send a request message to network node 208 to prepare candidate cell #2. For example, if UE 204's serving cell is cell #0 or the prepared candidate cell #1, then network node 206 CU may request network node 208 to indicate whether UE 204 can calculate the TA of candidate cell #2.

[0070] In some embodiments, at 217, network node 208 may transmit a response message in response to a request message. For example, if network node 208 determines that it accepts a request for LTM configuration related to at least one candidate cell (e.g., cell #A) in the request message, then network node 208 may transmit the configuration of the accepted candidate cell to network node 206.

[0071] In some embodiments, the response message may indicate a cell list. In some embodiments, the cell list may contain at least one cell for which the UE can obtain the TA of at least one candidate cell (e.g., cell #A) in the request message by performing a UE-based TA measurement. In some embodiments, the cell list may contain at least one cell belonging to network node 208 (e.g., cells in the cell list and cell #A belong to the same candidate DU) and satisfying the TAE requirement. For example, the cell list may contain the serving cell (e.g., cell #0) of UE 204 or a ready candidate cell (e.g., cell #1).

[0072] In the context of this disclosure, the TAE requirement can refer to the TAE between two cells within a specific time period (e.g., 260 ns), such that when the UE is served by one of the two cells, it can derive the TA of the other cell based on the UE's TA measurement.

[0073] By providing information related to the no-reset condition of cell #A, network node 206 can request network node 208 to determine whether UE 204 performs an L2 rest when the UE switches from another cell (e.g., cell #B') to cell #A (e.g., via an LTM cell handover procedure). Cell #B' can be the serving cell of UE 204 or a ready candidate cell for UE 204. For example, network node 208 may have transmitted the LTM configuration of cell #B' to network node 206. In response to the request message, network node 208 can provide the correlation between cell #A and cell #B'.

[0074] For example, at 217, network node 208 may transmit a response message in response to the request message. For example, if network node 208 determines that it accepts the request for LTM configuration related to at least one candidate cell (e.g., cell #A) in the request message, then network node 208 may transmit the configuration of the accepted candidate cell to network node 206.

[0075] In some embodiments, the response message may indicate a cell list. In some embodiments, the cell list may contain at least one cell, wherein when the UE switches from at least one cell in the cell list to cell #A, the UE does not need to perform an L2 reset. In some embodiments, the cell list may contain at least one cell belonging to network node 208 (e.g., the cells in the cell list and cell #A belong to the same candidate DU). For example, the cell list may contain the UE 204's currently serving cell or ready candidate cells.

[0076] In some embodiments, the request message at 215 can be a UE context setting request message, and the response message at 217 can be a UE context setting response message.

[0077] In some embodiments, network node 206 may not necessarily request information related to the TA or no reset measured by the UE of the candidate cell (e.g., cell #A) from the network node (e.g., candidate DU). That is, operations 215 and 217 can be omitted. Alternatively or supplemented, network node 206 may obtain this information from the Operation, Management, and Maintenance (OAM) entity. For example, network node 206 may send a request to OAM for information related to the TA or no reset measured by the UE of at least one candidate cell, and OAM may respond with the corresponding information.

[0078] At 219, network node 206 may transmit configuration to network node 202 via the F1 interface. The configuration may be based on the response message at 217.

[0079] At 221, network node 206 may (e.g., via network node 202) transmit a configuration to UE 204. The configuration may be based on a response message at 217. For example, the configuration to UE 204 may include LTM candidate cell configurations for one or more candidate cells (e.g., cell #A). In some instances, the LTM candidate cell configuration may be transmitted in a Radio Resource Control (RRC) reconfiguration message.

[0080] For example, in some embodiments, network node 206 may generate an RRC reconfiguration message based on configurations from candidate network nodes (e.g., information contained in a response message from network node 208). The RRC reconfiguration message contains LTM candidate cell configurations for one or more candidate cells (e.g., cell #A). For example, the RRC reconfiguration message may contain the TA ID (e.g., “ltm-UE-MeasuredTA-ID”) of the candidate cell (e.g., cell #A). For example, the RRC reconfiguration message may contain the no-reset ID (e.g., “ltm-NoResetID”) of the candidate cell (e.g., cell #A). For example, the RRC reconfiguration message may contain both the TA ID and the no-reset ID of the candidate cell (e.g., cell #A). Network node 206 may then transmit the RRC reconfiguration message to UE 204 via network node 202, which may be referred to as the “source network node” or “source DU”.

[0081] In some embodiments, the configuration to network node 202 may include information that assists network node 202 in determining whether to trigger UE 204 to perform an early TA acquisition procedure (e.g., not transmitting a preamble for early TA acquisition). For example, if UE 204 can obtain the TA of a candidate cell by performing UE-based TA measurements, network node 202 will not trigger UE 204 to perform an early TA acquisition procedure for the candidate cell.

[0082] For example, at 219, network node 206 may send a configuration instruction to network node 202 indicating one of the following:

[0083] (1a) One or more TA IDs measured by UE in the candidate cell (e.g., cell #A) of UE 204 and the TA ID measured by UE in the serving cell of UE 204 (e.g., “ltm-ServingCellUE-MeasuredTA-ID” as specified in the 3GPP standard);

[0084] (1b) A candidate cell list, wherein when performing an LTM cell handover procedure from the current serving cell to a corresponding candidate cell in the candidate cell list, the UE 204 is able to obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurements;

[0085] (1c) Correlation between multiple candidate cells (e.g., cell #A and cell #B), wherein when performing an LTM cell handover procedure from one cell (e.g., cell #B) to one cell (e.g., cell #A) among multiple candidate cells, UE204 is able to obtain the TA of one of the multiple candidate cells (e.g., cell #A) by performing UE-based TA measurement;

[0086] (1d) The association between the serving cell of UE 204 and at least one candidate cell configured for UE 204, wherein the serving cell and at least one candidate cell belong to the same network node and meet the TAE requirements.

[0087] For example, based on the response message received at 217, network node 206 knows that when performing an LTM cell handover procedure from the current serving cell to cell #A, UE 204 can obtain the TA of cell #A via UE-based TA measurement. Then, at 219, network node 206 can notify network node 202 of this information; for example, network node 206 can transmit a cell list containing cell #A to network node 202. Based on the cell list, network node 202 will not trigger UE 204 to transmit a preamble for early TA acquisition to cell #A.

[0088] In some embodiments, as an alternative or supplement, UE 204 itself may determine whether to perform TA acquisition upon triggering. For example, network node 206 may not transmit auxiliary information to network node 202 for determining whether to trigger an early TA acquisition procedure. UE 204 itself may determine whether to perform TA acquisition upon triggering by network node 202. For example, where UE 204 can obtain the TA of a candidate cell by performing UE-based TA measurement, UE 204 will ignore the physical downlink control channel (PDCCH) order used to trigger the candidate cell to acquire the TA from network node 202.

[0089] For example, in option 223 (indicated by the dashed arrow), UE 204 may receive from network node 202 the PDCCH order for triggering TA acquisition for the candidate cell. If UE 204 can obtain the TA for this candidate cell by performing UE-based TA measurements, for example, if the TA ID of the candidate cell measured by the UE is equal to the TA ID of the serving cell measured by the UE of UE 204, then UE 204 may ignore the PDCCH order.

[0090] In some embodiments, network node 202 may decide to perform a cell handover to a target cell. At 225, network node 202 may (e.g., via a Media Access Control (MAC) element (CE)) transmit an LTM cell handover command to UE 204. In some embodiments, network node 202 may also transmit a cell handover indication toward the target cell to network node 206.

[0091] Those skilled in the art should understand that the sequence of operations in exemplary method 200 may be altered and some operations in exemplary method 200 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0092] Figure 3 A flowchart illustrating an exemplary wireless communication method 300 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 3 The embodiments shown are illustrated below. For example, UE 304 can be used as... Figure 1 UE 104 in the network, and network node 302 can be used as Figure 1 The NE 103 shown in the figure. In some embodiments, network node 302 may include CU and at least one DU.

[0093] refer to Figure 3 In section 311, UE 304 may connect to (or access) network node 302. UE 304 may send measurement reports to network node 302. Network node 302 may be associated with either UE 304's MCG or SCG. For example, if UE 304 accesses the network via a single connection (e.g., via MCG only), network node 302 is associated with UE 304's MCG. If UE 304 accesses the network via dual connectivity (e.g., via both MCG and SCG), network node 302 may be associated with either UE 304's MCG or SCG.

[0094] Network node 302 can determine whether to initiate an LTM configuration procedure for UE 304. For example, at 315, network node 302 (also referred to as the serving or source BS of UE 304) can determine one or more candidate cells for LTM cell handover configuration of UE 304. Network node 302 can prepare LTM candidate cell configurations for one or more candidate cells. At 317, network node 302 can transmit the LTM configuration to UE 304. The LTM configuration can be transmitted via an RRC reconfiguration message. That is, the RRC reconfiguration message can contain the LTM configuration. Network node 302 can generate the RRC reconfiguration message based on the configuration from each candidate cell.

[0095] In some embodiments, for example, the LTM configuration transmitted to UE 304 may include LTM cell configurations of one or more candidate cells, UE measurement TA ID of the serving cell of UE 304 (e.g., “ltm-ServingCellUE-MeasuredTA-ID”), UE measurement TA ID of a candidate cell among one or more candidate cells (e.g., “ltm-UE-MeasuredTA-ID”), no-reset ID of the serving cell of UE 304 (e.g., “ltm-ServingCellNoResetID”), no-reset ID of a candidate cell among one or more candidate cells (e.g., “ltm-NoResetID”), or any combination thereof.

[0096] At 319, network node 302 may issue a handover command (e.g., L3 handover) to instruct UE 304 to hand over to a target cell. For example, the handover command may indicate the target cell (referred to as cell #C below for clarity). This handover command may trigger a change in the primary cell (PCell) or primary secondary cell (PSCell) at UE 304.

[0097] In 321, UE 304 may perform a handover from its current serving cell to cell #C in response to receiving a handover command. It would be beneficial if UE 304 could update its LTM configuration stored at UE 304 in response to receiving a handover command.

[0098] For example, in some embodiments, in response to receiving a handover command (e.g., after a handover procedure), UE304 may set the TA ID of the UE measurement of the serving cell or the no-reset ID of the serving cell based on an RRC reconfiguration message or LTM configuration.

[0099] For example, in response to receiving a handover command and cell #C being one of one or more candidate cells, UE304 may set the value of the TA ID (e.g., “ltm-ServingCellUE-MeasuredTA-ID”) of the serving cell to the value of the TA ID (e.g., “ltm-UE-MeasuredTA-ID”) of cell #C indicated in the LTM configuration.

[0100] For example, in response to receiving a handover command and cell #C not being one of one or more candidate cells, UE 304 may receive the UE-measured TA ID (e.g., “ltm-UE-MeasuredTA-ID”) of cell #C from network node 302 and set the value of the UE-measured TA ID of the serving cell (e.g., “ltm-ServingCellUE-MeasuredTA-ID”) to the value of the received UE-measured TA ID of cell #C. In some embodiments, UE 304 may receive the UE-measured TA ID of cell #C in or before the handover command. For example, the handover command may include the UE-measured TA ID of cell #C.

[0101] For example, if cell #C is one of one or more candidate cells and the value of "ltm-ServingCellUE-MeasuredTA-ID" is different from the value of "ltm-UE-MeasuredTA-ID" associated with cell #C as indicated in the LTM configuration, then UE 304 replaces "ltm-ServingCellUE-MeasuredTA-ID" with the "ltm-UE-MeasuredTA-ID" associated with cell #C. If cell #C is one of one or more candidate cells and the value of "ltm-ServingCellUE-MeasuredTA-ID" is the same as the value of "ltm-UE-MeasuredTA-ID" associated with cell #C, then UE 304 retains the current value of "ltm-ServingCellUE-MeasuredTA-ID". For example, if cell #C is not one of the candidate cells, then UE 304 can receive the "ltm-UE-MeasuredTA-ID" associated with cell #C from network node 302 and replace the "ltm-ServingCellUE-MeasuredTA-ID" with the received "ltm-UE-MeasuredTA-ID" associated with cell #C. In other words, network node 302 configures the "ltm-UE-MeasuredTA-ID" associated with cell #C to UE 304.

[0102] For example, in response to receiving a handover command and cell #C being one of one or more candidate cells, UE304 may set the value of the no-reset ID of the serving cell (e.g., “ltm-ServingCellNoResetID”) to the value of the no-reset ID of cell #C (e.g., “ltm-NoResetID”) indicated in the LTM configuration.

[0103] For example, in response to receiving a handover command and cell #C not being one of one or more candidate cells, UE 304 may receive the no-reset ID (e.g., "ltm-NoResetID") of cell #C from network node 302 and set the value of the no-reset ID of the serving cell (e.g., "ltm-ServingCellNoResetID") to the value of the received no-reset ID of cell #C. In some embodiments, UE 304 may receive the no-reset ID of cell #C in or before the handover command. For example, the handover command may include the no-reset ID of cell #C.

[0104] For example, if cell #C is one of the candidate cells and the value of "ltm-ServingCellNoResetID" is different from the value of "ltm-NoResetID" associated with cell #C indicated in the LTM configuration, then UE 304 replaces "ltm-ServingCellNoResetID" with the "ltm-NoResetID" associated with cell #C. If cell #C is one of the candidate cells and the value of "ltm-ServingCellNoResetID" is the same as the value of "ltm-NoResetID" associated with cell #C, then UE 304 retains the current value of "ltm-ServingCellNoResetID". For example, if cell #C is not one of the candidate cells, then UE 304 may receive the "ltm-NoResetID" associated with cell #C from network node 302 and replace "ltm-ServingCellNoResetID" with the received "ltm-NoResetID" associated with cell #C. In other words, network node 302 configures “ltm-NoResetID” related to cell #C to UE 304.

[0105] In some embodiments, when network node 302 decides to hand over UE 304 to cell #C, it may always configure the TA ID or No Reset ID of UE measurements for cell #C. That is, regardless of whether cell #C is one of one or more candidate cells in the LTM configuration, network node 302 may configure the TA ID or No Reset ID of UE measurements for cell #C to UE 304. For example, the handover command may include the TA ID or No Reset ID of UE measurements for cell #C. In response to receiving the handover command (e.g., after a handover procedure), UE 304 may set the TA ID or No Reset ID of UE measurements for the serving cell to the TA ID or No Reset ID of UE measurements for cell #C.

[0106] Those skilled in the art should understand that the sequence of operations in exemplary method 300 may be changed and some operations in exemplary method 300 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0107] Figure 4 A flowchart illustrating an exemplary wireless communication method 400 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 4 The embodiments shown are illustrated below. For example, UE 404 can be used as... Figure 1 UE 104 in the network, and network node 402 can be used as Figure 1 The NE 104 shown in the figure. In some embodiments, network node 402 may include CU and at least one DU.

[0108] refer to Figure 4 At 411, UE 404 may connect to (or access) network node 402. UE 404 may send measurement reports to network node 402. Network node 402 may be associated with either the MCG or SCG of UE 404. For example, if UE 404 accesses the network via a single connection (e.g., via MCG only), network node 402 is associated with the MCG of UE 404. If UE 404 accesses the network via dual connectivity (e.g., via both MCG and SCG), network node 402 may be associated with either the MCG or SCG of UE 404.

[0109] Network node 402 may initiate an LTM configuration procedure for UE 404. For example, at 415, network node 402 (also referred to as the serving or source BS of UE 404) may determine one or more candidate cells for LTM cell handover configuration of UE 404. Network node 402 may prepare LTM candidate cell configurations for one or more candidate cells. At 417, network node 402 may transmit the LTM configuration to UE 404. The LTM configuration may be transmitted via an RRC reconfiguration message. That is, the RRC reconfiguration message may contain the LTM configuration. Network node 402 may generate the RRC reconfiguration message based on the configuration from each candidate cell.

[0110] In some embodiments, for example, the LTM configuration transmitted to UE 404 may include LTM cell configurations of one or more candidate cells, UE measurement TA IDs of the serving cell of UE 404 (e.g., “ltm-ServingCellUE-MeasuredTA-ID”), UE measurement TA IDs of candidate cells among one or more candidate cells (e.g., “ltm-UE-MeasuredTA-ID”), no-reset IDs of the serving cell of UE 404 (e.g., “ltm-ServingCellNoResetID”), no-reset IDs of candidate cells among one or more candidate cells (e.g., “ltm-NoResetID”), or any combination thereof.

[0111] In some embodiments, network node 402 may transmit a conditional path handover configuration (e.g., a CHO or CPC configuration) to UE 404. For example, the configuration may be included in an RRC configuration message. For example, the configuration may indicate at least one candidate cell for the CHO or CPC and the corresponding conditions for the CHO or CPC to the candidate cells. UE 404 may evaluate the conditions for the CHO or CPC. At 419, UE 404 may determine that the conditions for handover to a cell (hereinafter referred to as cell #D for clarity) are met, and may then perform a path handover to cell #D. This path handover may be a PCell change or a PSCell change.

[0112] It would be advantageous if UE 404 could update the LTM configuration stored at UE 404 in response to a conditional path handover. In some embodiments, UE 404 may receive the TA ID of UE measurements for cell #D or the no-reset ID of cell #D from network node 402. For example, the TA ID of UE measurements for cell #D or the no-reset ID of cell #D may be included in an RRC reconfiguration message containing a CHO or CPC configuration. In response to the fulfillment of the conditions for handover to cell #D (e.g., after a CHO or CPC procedure), UE 404 may set the TA ID of UE measurements for the serving cell or the no-reset ID of the serving cell based on the RRC reconfiguration message. For example, in response to the fulfillment of the conditions for handover to cell #D, UE 404 may set the value of the TA ID of UE measurements for the serving cell or the no-reset ID of the serving cell to the value of the received TA ID of UE measurements for cell #D.

[0113] Those skilled in the art should understand that the sequence of operations in exemplary method 400 may be changed and some operations in exemplary method 400 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0114] Figure 5A flowchart illustrating a wireless communication method 500 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 5 The embodiments shown are illustrated below. In some instances, method 500 may be performed by a network node (e.g., a BS, NE, a CU of the BS, or a CU of the NE). In some embodiments, the network node may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations.

[0115] At 511, the first network node may transmit a request message to the second network node, wherein the request message includes the ID of the first candidate cell and an indication requesting information related to the TA or no reset of the UE measurement of the first candidate cell. At 513, the first network node may receive a response message from the second network node in response to the request message. At 515, the first network node may transmit configuration to the UE, a third network node, or both based on the response message.

[0116] In some embodiments of this disclosure, information related to the TA (Transmission Aspect) measured by the UE in the first candidate cell may indicate whether the UE can obtain the TA of the first candidate cell by performing a UE-based TA measurement when an LTM cell handover procedure is performed from the second cell to the first candidate cell. In some embodiments of this disclosure, the response message may indicate a list of cells containing: at least one cell in which the UE can obtain the TA of the first candidate cell by performing a UE-based TA measurement; or at least one cell belonging to the second network node and satisfying the TAE (Transmission Aspect) requirement.

[0117] In some embodiments of this disclosure, information related to the absence of a reset in the first candidate cell may indicate whether the UE performs an L2 reset when switching from a second cell to the first candidate cell. In some embodiments of this disclosure, the response message may indicate a list of cells containing: at least one cell from which the UE does not perform an L2 reset when switching from the at least one cell to the first candidate cell; or at least one cell belonging to a second network node.

[0118] In some embodiments of this disclosure, the second cell may include the UE's serving cell or its LTM configuration that has been provided by the second network node to the first network node as a candidate cell.

[0119] In some embodiments of this disclosure, the cell list may include a second cell.

[0120] In some embodiments of this disclosure, the configuration may indicate one of the following: one or more UE-measured TA IDs of a first candidate cell and UE-measured TA IDs of the UE's serving cell; a candidate cell list, wherein when performing an LTM cell handover procedure from the serving cell to a corresponding candidate cell in the candidate cell list, the UE can obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurements; the association between the first candidate cell and a second candidate cell, wherein when performing an LTM cell handover procedure from the second candidate cell to the first candidate cell, the UE can obtain the TA of the first candidate cell by performing UE-based TA measurements; and the association between the UE's serving cell and at least one candidate cell, wherein the serving cell and at least one candidate cell belong to the same network node and satisfy the TAE requirement.

[0121] In some embodiments of this disclosure, the first network node is associated with the UE's MCG or the UE's SCG.

[0122] Those skilled in the art should understand that the sequence of operations in exemplary method 500 may be changed and some operations in exemplary method 500 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0123] Figure 6 A flowchart illustrating a wireless communication method 600 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 6 The embodiments shown are illustrated below. In some instances, method 600 may be performed by a network node (e.g., BS, NE, DU of BS, or DU of NE). In some embodiments, the network node may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations.

[0124] At 611, the second network node may receive a request message from the first network node, wherein the request message contains the ID of the first candidate cell and an indication requesting information related to the TA or no reset of the UE measurement of the first candidate cell. At 613, the second network node may transmit a response message to the first network node in response to the request message.

[0125] In some embodiments of this disclosure, information related to the TA measured by the UE in the first candidate cell may indicate whether the UE is able to obtain the TA of the first candidate cell by performing a UE-based TA measurement when performing an LTM cell handover procedure from the second cell to the first candidate cell.

[0126] In some embodiments of this disclosure, the response message may indicate a list of cells that includes: at least one cell for which the UE can obtain the TA of a first candidate cell by performing a UE-based TA measurement; or at least one cell that belongs to a second network node and meets the TAE requirements.

[0127] In some embodiments of this disclosure, information related to the absence of a reset in the first candidate cell may indicate whether the UE performs an L2 reset when switching from the second cell to the first candidate cell.

[0128] In some embodiments of this disclosure, the response message may indicate a list of cells that includes: at least one cell from which the UE does not perform an L2 reset when the UE switches from the at least one cell to a first candidate cell; or at least one cell belonging to a second network node.

[0129] In some embodiments of this disclosure, the second cell may include the UE's serving cell or its LTM configuration that has been provided to the first network node by the second network node.

[0130] In some embodiments of this disclosure, the cell list may include a second cell.

[0131] Those skilled in the art should understand that the sequence of operations in exemplary method 600 may be changed and some operations in exemplary method 600 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0132] Figure 7 A flowchart illustrating a wireless communication method 700 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 7 The embodiments shown are illustrated below. In some instances, method 700 may be performed by a network node (e.g., BS, NE, DU of BS, or DU of NE). In some embodiments, the network node may execute a set of instructions to control the functional elements of the network node to perform the described functions or operations.

[0133] At 711, the third network node may receive configuration from the first network node, wherein the configuration contains information related to the TA measured by the UE for the first candidate cell. At 713, the third network node may determine, based on the received configuration, whether to trigger the UE to perform early TA acquisition regarding the first candidate cell.

[0134] In some embodiments of this disclosure, the configuration may indicate one of the following: one or more UE-measured TA IDs of a first candidate cell and UE-measured TA IDs of the UE's serving cell; a candidate cell list, wherein when performing an LTM cell handover procedure from the serving cell to a corresponding candidate cell in the candidate cell list, the UE can obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurements; the association between the first candidate cell and a second candidate cell, wherein when performing an LTM cell handover procedure from the second candidate cell to the first candidate cell, the UE can obtain the TA of the first candidate cell by performing UE-based TA measurements; and the association between the UE's serving cell and at least one candidate cell, wherein the serving cell and at least one candidate cell belong to the same network node and satisfy the TAE requirement.

[0135] Those skilled in the art should understand that the sequence of operations in exemplary method 700 may be changed and some operations in exemplary method 700 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0136] Figure 8 A flowchart illustrating a wireless communication method 800 according to some embodiments of the present disclosure. The details described in all the foregoing embodiments of the present disclosure are applicable to... Figure 8 The embodiments shown are illustrated below. In some instances, method 800 may be performed by a UE (e.g., referring to...). Figure 1 The UE 104 described herein is executed. In some embodiments, the UE may execute a set of instructions to control the functional elements of the UE to perform the described functions or operations.

[0137] In step 811, the UE may receive a reconfiguration message from the network node containing the LTM configuration of one or more candidate cells. In step 813, the UE may, in response to receiving a handover command to a second cell or in response to meeting the conditions for handover to a second cell, hand over from the UE's serving cell to a second cell and set the UE-measured TAID of the serving cell or the non-reset ID of the serving cell based on the reconfiguration message.

[0138] In some embodiments of this disclosure, in order to set the TA ID measured by the UE of the serving cell, the UE may perform one or more of the following: in response to receiving a handover command and the second cell being one of one or more candidate cells, setting the value of the TA ID measured by the UE of the serving cell to the value of the TA ID measured by the UE of the second cell as indicated in the LTM configuration; in response to receiving a handover command and the second cell not being one of one or more candidate cells, receiving the TA ID measured by the UE of the second cell from the network node and setting the value of the TA ID measured by the UE of the serving cell to the value of the TA ID measured by the UE of the second cell received; and in response to satisfying the conditions for handover to the second cell, receiving the TA ID measured by the UE of the second cell from the network node and setting the value of the TA ID measured by the UE of the serving cell to the value of the TA ID measured by the UE of the second cell received.

[0139] In some embodiments of this disclosure, in order to set the no-reset ID of the serving cell, the UE may perform one or more of the following: in response to receiving a handover command and the second cell being one of one or more candidate cells, setting the value of the no-reset ID of the serving cell to the value of the no-reset ID of the second cell indicated in the LTM configuration; in response to receiving a handover command and the second cell not being one of one or more candidate cells, receiving the no-reset ID of the second cell from the network node and setting the value of the received no-reset ID of the serving cell to the value of the no-reset ID of the second cell; and in response to satisfying the conditions for handover to the second cell, receiving the no-reset ID of the second cell from the network node and setting the value of the no-reset ID of the serving cell to the value of the received no-reset ID of the second cell.

[0140] In some embodiments of this disclosure, in order to receive the TA ID measured by the UE of the second cell or the no-reset ID of the second cell, the UE may receive the TA ID measured by the UE of the second cell or the no-reset ID of the second cell in or before the handover command or the condition for handover to the second cell.

[0141] In some embodiments of this disclosure, the conditions for switching to a second cell are related to CHO or CPC.

[0142] Those skilled in the art should understand that the sequence of operations in exemplary method 800 may be changed and some operations in exemplary method 800 may be omitted or modified without departing from the spirit and scope of this disclosure.

[0143] Figure 9An example of a UE 900 according to aspects of this disclosure is described. UE 900 may include a processor 902, a memory 904, a controller 906, and a transceiver 908. The processor 902, memory 904, controller 906, or transceiver 908, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure described herein. These components may be coupled via one or more interfaces (e.g., operatively, communicatively, functionally, electronically, or electrically).

[0144] Processor 902, memory 904, controller 906, or transceiver 908, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may include processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), or other programmable logic devices, or any combination thereof configured or otherwise supporting components for performing the functions described in this disclosure.

[0145] Processor 902 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, ASICs, FPGAs, or any combination thereof). In some embodiments, processor 902 may be configured to operate memory 904. In some other embodiments, memory 904 may be integrated into processor 902. Processor 902 may be configured to execute computer-readable instructions stored in memory 904 to cause UE 900 to perform various functions of this disclosure.

[0146] Memory 904 may comprise volatile or non-volatile memory. Memory 904 may store computer-readable, computer-executable code containing instructions that, when executed by processor 902, cause UE 900 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 904 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media, including any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media may be any available medium accessible by a general-purpose or special-purpose computer.

[0147] In some implementations, processor 902 and memory 904 coupled to processor 902 may be configured to cause UE 900 to perform one or more of the functions described herein (e.g., processor 902 executing instructions stored in memory 904). For example, processor 902 may support wireless communication at UE 900 according to the examples disclosed herein.

[0148] For example, UE 900 can be configured to support the execution of [specific actions / functions]. Figure 8The components of the described operation. For example, UE 900 may be configured to support: a component for receiving a reconfiguration message from a network node containing LTM configurations of one or more candidate cells; and a component for switching from the UE's serving cell to a second cell in response to receiving a handover command to a second cell or in response to meeting the conditions for switching to a second cell, and setting the UE-measured TA ID of the serving cell or the non-reset ID of the serving cell based on the reconfiguration message.

[0149] Controller 906 manages the input and output signals of UE 900. Controller 906 can also manage peripheral devices not integrated into UE 900. In some embodiments, controller 906 may utilize an operating system, such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some embodiments, controller 906 may be implemented as part of processor 902.

[0150] In some embodiments, UE 900 may include at least one transceiver 908. In other embodiments, UE 900 may have more than one transceiver 908. Transceiver 908 may represent a wireless transceiver. Transceiver 908 may include one or more receiver chains 910, one or more transmitter chains 912, or a combination thereof.

[0151] Receiver chain 910 may be configured to receive signals (e.g., control information, data, packets) via a wireless medium. For example, receiver chain 910 may include one or more antennas for receiving signals over the air or via a wireless medium. Receiver chain 910 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. Receiver chain 910 may include at least one demodulator configured to demodulate the received signal by reversing the modulation technique applied during signal transmission and to obtain the transmitted data. Receiver chain 910 may include at least one decoder for decoding and processing the demodulated signal to receive the transmitted data.

[0152] Transmitter chain 912 can be configured to generate and transmit signals (e.g., control information, data, or packets). Transmitter chain 912 may include at least one modulator for modulating data onto a carrier signal in preparation for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase shift keying (PSK) or quadrature amplitude modulation (QAM). Transmitter chain 912 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 912 may also include one or more antennas for transmitting the amplified signal into the air or a wireless medium.

[0153] Those skilled in the art will understand that components in the exemplary UE 900 can be changed; for example, some components in the exemplary UE 900 can be omitted or modified, or new components can be added to the exemplary UE 900 without departing from the spirit and scope of this disclosure. For instance, in some embodiments, the UE 900 may not include the controller 906.

[0154] Figure 10 An example of a processor 1000 according to aspects of this disclosure is described. Processor 1000 may be an example of a processor configured to perform various operations according to the examples described herein. Processor 1000 may include a controller 1002 configured to perform various operations according to the examples described herein. Processor 1000 may optionally include at least one memory 1004, which may be, for example, an L1 / L2 / L3 cache. Additionally or alternatively, processor 1000 may optionally include one or more arithmetic logic units (ALUs) 1006. One or more of these components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0155] Processor 1000 may be a processor chipset and includes a protocol stack (e.g., a software stack), which is executed by the processor chipset to perform various operations (e.g., receive, acquire, retrieve, transmit, output, forward, store, determine, identify, access, write, read) according to the examples described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to the processor chipset (e.g., processor 1000) or included in the processor chipset) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), and others).

[0156] Controller 1002 can be configured to manage and coordinate various operations of processor 1000 (e.g., signaling, receiving, acquiring, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, and reading) to enable processor 1000 to support various operations according to the examples described herein. For example, controller 1002 can operate as a control unit of processor 1000, generating control signals that manage the operation of various components of processor 1000. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating operation timing.

[0157] Controller 1002 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from memory 1004 and determine subsequent instructions to be executed to enable processor 1000 to support various operations according to the examples described herein. Controller 1002 may be configured to track the memory addresses of instructions associated with memory 1004. Controller 1002 may be configured to decode instructions to determine the operations to be performed and the operands involved. For example, controller 1002 may be configured to interpret instructions and determine control signals to be output to other components of processor 1000 to enable processor 1000 to support various operations according to the examples described herein. Alternatively or additionally, controller 1002 may be configured to manage data flow within processor 1000. Controller 1002 may be configured to control data transfers between registers, ALU, and other functional units of processor 1000.

[0158] Memory 1004 may include one or more caches (e.g., memory local to or included in processor 1000) or other memories, such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some embodiments, memory 1004 may reside within or on the processor chipset (e.g., locally to processor 1000). In some other embodiments, memory 1004 may reside outside the processor chipset (e.g., remotely from processor 1000).

[0159] Memory 1004 may store computer-readable, computer-executable code containing instructions that, when executed by processor 1000, cause processor 1000 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. Controller 1002 and / or processor 1000 may be configured to execute the computer-readable instructions stored in memory 1004 to cause processor 1000 to perform various functions. For example, processor 1000 and / or controller 1002 may be coupled to or coupled to memory 1004, and processor 1000, controller 1002, and memory 1004 may be configured to perform the various functions described herein. In some instances, processor 1000 may include multiple processors, and memory 1004 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, which may be individually or jointly configured to perform the various functions described herein.

[0160] One or more ALUs 1006 may be configured to support various operations according to the examples described herein. In some embodiments, one or more ALUs 1006 may reside within or on a processor chipset (e.g., processor 1000). In some other embodiments, one or more ALUs 1006 may reside outside the processor chipset (e.g., processor 1000). One or more ALUs 1006 may perform one or more computations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALUs 1006 may receive input operands and opcodes, which determine the operation to be performed. One or more ALUs 1006 are configured with various logic and arithmetic circuitry, including adders, subtractors, shifters, and logic gates, to process and manipulate data according to the operation. Alternatively, one or more ALU 1006 may support logical operations such as AND, OR, XOR, NOR, and NAND, enabling one or more ALU 1006 to handle conditional operations, comparisons, and bitwise operations.

[0161] The processor 1000 can support wireless communication according to the examples disclosed herein.

[0162] For example, processor 1000 can be configured to support the execution of tasks related to... Figure 5 The described operation includes components. For example, the processor 1000 may be configured or operable to support: components for transmitting a request message to a second network node, wherein the request message may include the ID of a first candidate cell and an indication of requesting information related to the TA or no reset of the UE measured in the first candidate cell; components for receiving a response message from the second network node in response to the request message; and components for transmitting a configuration to the UE, a third network node, or both based on the response message.

[0163] For example, processor 1000 can be configured to support the execution of tasks related to... Figure 6 The described operation is a component. For example, the processor 1000 may be configured or operable to support: a component for receiving a request message from a first network node, wherein the request message may include the ID of a first candidate cell and an indication of requesting information related to the TA or no reset of the UE measurement of the first candidate cell; and a component for transmitting a response message to the first network node in response to the request message.

[0164] For example, processor 1000 can be configured to support the execution of tasks related to... Figure 7The described operation is a component. For example, the processor 1000 may be configured or operable to support: a component for receiving configuration from a first network node, wherein the configuration may include information related to the TA measured by the UE for the first candidate cell; and a component for determining, based on the received configuration, whether to trigger the UE to perform early TA acquisition with respect to the first candidate cell.

[0165] For example, processor 1000 can be configured to support the execution of tasks related to... Figure 8 The described operation is a component. For example, the processor 1000 may be configured or operable to support: a component for receiving a reconfiguration message from a network node containing LTM configurations of one or more candidate cells; and a component for switching from the UE's serving cell to a second cell in response to receiving a handover command to a second cell or in response to meeting the conditions for switching to a second cell, and setting the UE-measured TA ID of the serving cell or the non-reset ID of the serving cell based on the reconfiguration message.

[0166] Those skilled in the art will understand that components in the exemplary processor 1000 can be changed; for example, some components in the exemplary processor 1000 can be omitted or modified, or new components can be added to the exemplary processor 1000, without departing from the spirit and scope of this disclosure. For example, in some embodiments, the processor 1000 may not include an ALU 1006.

[0167] Figure 11 An example of NE 1100 according to aspects of this disclosure is described. NE 1100 may include a processor 1102, a memory 1104, a controller 1106, and a transceiver 1108. The processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations thereof, or various components thereof, may be examples of components for performing the aspects of this disclosure described herein. These components may be coupled via one or more interfaces (e.g., operatively, communicatively, functionally, electronically, electrically).

[0168] Processor 1102, memory 1104, controller 1106, or transceiver 1108, or various combinations or components thereof, may be implemented in hardware (e.g., a circuit system). The hardware may include processors, DSPs, ASICs, or other programmable logic devices, or any combination thereof configured or otherwise supporting components for performing the functions described in this disclosure.

[0169] Processor 1102 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, ASICs, FPGAs, or any combination thereof). In some embodiments, processor 1102 may be configured to operate memory 1104. In some other embodiments, memory 1104 may be integrated into processor 1102. Processor 1102 may be configured to execute computer-readable instructions stored in memory 1104 to cause NE 1100 to perform various functions of this disclosure.

[0170] Memory 1104 may comprise volatile or non-volatile memory. Memory 1104 may store computer-readable, computer-executable code containing instructions that, when executed by processor 1102, cause NE 1100 to perform the various functions described herein. The code may be stored in a non-transitory computer-readable medium, such as memory 1104 or another type of memory. Computer-readable media include both non-transitory computer storage media and communication media, encompassing any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media may be any available medium accessible by a general-purpose or special-purpose computer.

[0171] In some implementations, processor 1102 and memory 1104 coupled to processor 1102 may be configured to cause NE 1100 to perform one or more of the functions described herein (e.g., instructions stored in memory 1104 are executed by processor 1102). For example, processor 1102 may support wireless communication at NE 1100 according to the examples disclosed herein.

[0172] For example, the NE 1100 can be configured to support the execution of [specific actions / functions]. Figure 5 The components of the described operation. For example, the NE 1100 may be configured or operable to support: components for transmitting a request message to a second network node, wherein the request message may include the ID of a first candidate cell and an indication of requesting TA or no-reset information related to the UE measurement of the first candidate cell; components for receiving a response message from the second network node in response to the request message; and components for transmitting configuration to the UE, a third network node, or both based on the response message.

[0173] For example, the NE 1100 can be configured to support the execution of [specific actions / functions]. Figure 6 The described operation is a component. For example, the NE 1100 may be configured or operable to support: a component for receiving a request message from a first network node, wherein the request message may contain the ID of a first candidate cell and an indication of requesting information related to the TA or no reset of the UE measurement of the first candidate cell; and a component for transmitting a response message to the first network node in response to the request message.

[0174] For example, the NE 1100 can be configured to support the execution of [specific actions / functions]. Figure 7 The described operation is a component. For example, the NE 1100 may be configured or operable to support: a component for receiving configuration from a first network node, wherein the configuration may include information related to the TA measured by the UE for the first candidate cell; and a component for determining, based on the received configuration, whether to trigger the UE to perform early TA acquisition for the first candidate cell.

[0175] Controller 1106 manages the input and output signals of NE 1100. Controller 1106 can also manage peripheral devices not integrated into NE 1100. In some embodiments, controller 1106 may utilize an operating system, such as iOS®, Android®, Windows®, or other operating systems. In some embodiments, controller 1106 may be implemented as part of processor 1102.

[0176] In some embodiments, NE 1100 may include at least one transceiver 1108. In other embodiments, NE 1100 may have more than one transceiver 1108. Transceiver 1108 may represent a wireless transceiver. Transceiver 1108 may include one or more receiver chains 1110, one or more transmitter chains 1112, or a combination thereof.

[0177] Receiver chain 1110 may be configured to receive signals (e.g., control information, data, or packets) via a wireless medium. For example, receiver chain 1110 may include one or more antennas for receiving signals over the air or via a wireless medium. Receiver chain 1110 may include at least one amplifier (e.g., an LNA) configured to amplify the received signal. Receiver chain 1110 may include at least one demodulator configured to demodulate the received signal by reversing the modulation technique applied during signal transmission and to obtain the transmitted data. Receiver chain 1110 may include at least one decoder for decoding and processing the demodulated signal to receive the transmitted data.

[0178] Transmitter chain 1112 can be configured to generate and transmit signals (e.g., control information, data, or packets). Transmitter chain 1112 may include at least one modulator for modulating data onto a carrier signal in preparation for transmission over a wireless medium. The at least one modulator may be configured to support one or more technologies, such as AM, FM, or digital modulation schemes like PSK or QAM. Transmitter chain 1112 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. Transmitter chain 1112 may also include one or more antennas for transmitting the amplified signal into the air or a wireless medium.

[0179] Those skilled in the art will understand that components in the exemplary NE 1100 can be changed; for example, some components in the exemplary NE 1100 can be omitted or modified, or new components can be added to the exemplary NE 1100 without departing from the spirit and scope of this disclosure. For instance, in some embodiments, the NE 1100 may not include the controller 1106.

[0180] Those skilled in the art will understand that the operations or steps of the methods described in connection with the aspects disclosed herein can be directly embodied in hardware, a software module executed by a processor, or a combination of both. The software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. Furthermore, in some aspects, the operations or steps of the method can reside as one or any combination or set of code and / or instructions on a non-transitory computer-readable medium, which can be incorporated into a computer program product.

[0181] While this disclosure has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications, and variations will be readily apparent. This disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Furthermore, operation of the disclosed embodiments does not necessarily require all elements of each figure. For example, the teachings of this disclosure will enable those of ordinary skill in the art to make and use the disclosed embodiments by simply employing the elements of the independent claims. Therefore, the embodiments of this disclosure set forth herein are intended to be illustrative rather than restrictive. Various changes may be made without departing from the spirit and scope of this disclosure.

[0182] In this document, the terms “switch” and “path switch” are used interchangeably. The terms “path switch” and “path change” are used interchangeably. The term “comprising” or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but may also include other elements not expressly listed or inherent to the process, method, article, or apparatus. An element beginning with “a” or the like does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element, without further constraints. Moreover, the term “another” is defined as at least a second or more. As used herein, the term “having” or the like is defined as “comprising”. For example, expressions such as “A and / or B” or “at least one of A and B” may include any and all combinations of the words listed with the expression. For example, the expression “A and / or B” or “at least one of A and B” may include A, B, or both A and B. The wording “first,” “second,” or the like is used only to clearly illustrate embodiments of this disclosure and is not intended to limit the nature of this disclosure.

Claims

1. A first network node, comprising: At least one memory; and At least one processor, coupled to the at least one memory and configured to enable the first network node to: A request message is sent to the second network node, wherein the request message includes the ID of the first candidate cell and an indication of requesting information related to the timing advance TA or no reset of the user equipment UE measurement of the first candidate cell; Receive a response message from the second network node in response to the request message; and Based on the response message, a configuration is transmitted to the UE, a third network node, or both.

2. The first network node according to claim 1, wherein the information related to the TA measured by the UE of the first candidate cell indicates whether the UE can obtain the TA of the first candidate cell by performing UE-based TA measurement when executing an L1 / L2 triggered mobility LTM cell handover procedure from the second cell to the first candidate cell.

3. The first network node according to claim 2, wherein the response message indication includes a list of cells including: The UE is based on its ability to obtain the TA of the first candidate cell by performing UE-based TA measurements; or At least one cell that belongs to the second network node and meets the time alignment error (TAE) requirement.

4. The first network node according to claim 1, wherein the information related to the no-reset of the first candidate cell indicates whether the UE performs an L2 reset when the UE switches from the second cell to the first candidate cell.

5. The first network node according to claim 4, wherein the response message indication includes a list of cells including: In at least one cell, when the UE switches from the at least one cell to the first candidate cell, the UE does not perform an L2 reset; or At least one cell belonging to the second network node.

6. The first network node according to any one of claims 2 to 5, wherein the second cell includes the serving cell of the UE or its L1 / L2 triggered mobility LTM configuration provided by the second network node to the candidate cell of the first network node.

7. The first network node according to claim 3 or 5, wherein the cell list includes the second cell.

8. The first network node of claim 1, wherein the configuration indicates one of the following: The TA ID measured by one or more UEs in the first candidate cell and the TA ID measured by the UE in the serving cell of the UE; A candidate cell list, wherein when an L1 / L2 triggered mobility LTM cell handover procedure is performed from the serving cell to a corresponding candidate cell in the candidate cell list, the UE can obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurement; The correlation between the first candidate cell and the second candidate cell, wherein when an LTM cell handover procedure is performed from the second candidate cell to the first candidate cell, the UE is able to obtain the TA of the first candidate cell by performing UE-based TA measurement; The association between the serving cell and at least one candidate cell of the UE, wherein the serving cell and the at least one candidate cell belong to the same network node and meet the time alignment error (TAE) requirement.

9. The first network node according to claim 1, wherein the first network node is associated with the primary cell group (MCG) of the UE or the secondary cell group (SCG) of the UE.

10. A second network node, comprising: At least one memory; and At least one processor, coupled to the at least one memory and configured to enable the second network node to: Receive a request message from a first network node, wherein the request message includes the ID of a first candidate cell and an indication requesting information related to the timing advance (TA) or no reset of the user equipment (UE) measurement of the first candidate cell; and In response to the request message, a response message is sent to the first network node.

11. The second network node of claim 10, wherein the information related to the TA measured by the UE of the first candidate cell indicates whether the UE can obtain the TA of the first candidate cell by performing a UE-based TA measurement when an L1 / L2 triggered mobility LTM cell handover procedure from the second cell to the first candidate cell is executed.

12. The second network node of claim 11, wherein the response message indication includes a list of cells including: The UE is based on its ability to obtain the TA of the first candidate cell by performing UE-based TA measurements; or At least one cell that belongs to the second network node and meets the time alignment error (TAE) requirement.

13. The second network node of claim 10, wherein the information related to the lack of reset in the first candidate cell indicates whether the UE performs an L2 reset when the UE switches from the second cell to the first candidate cell.

14. The second network node of claim 13, wherein the response message indication includes a list of cells of the following: In at least one cell, when the UE switches from the at least one cell to the first candidate cell, the UE does not perform an L2 reset; or At least one cell belonging to the second network node.

15. The second network node according to any one of claims 11 to 14, wherein the second cell includes the serving cell of the UE or its L1 / L2 triggered mobility LTM configuration that has been provided by the second network node to the first network node.

16. The second network node according to claim 12 or 14, wherein the cell list includes the second cell.

17. A third network node, comprising: At least one memory; and At least one processor, coupled to the at least one memory and configured to enable the third network node to: Receive configuration from a first network node, wherein the configuration includes information related to the timing advance (TA) of a user equipment (UE) measurement of a first candidate cell; and Based on the received configuration, it is determined whether to trigger the UE to perform early TA acquisition for the first candidate cell.

18. The third network node of claim 17, wherein the configuration indicates one of the following: The TA ID measured by one or more UEs in the first candidate cell and the TA ID measured by the UE in the serving cell of the UE; A candidate cell list, wherein when an L1 / L2 triggered mobility LTM cell handover procedure is performed from the serving cell to a corresponding candidate cell in the candidate cell list, the UE can obtain the TA of each candidate cell in the candidate cell list by performing UE-based TA measurement; The correlation between the first candidate cell and the second candidate cell, wherein when an LTM cell handover procedure is performed from the second candidate cell to the first candidate cell, the UE is able to obtain the TA of the first candidate cell by performing UE-based TA measurement; and The association between the serving cell and at least one candidate cell of the UE, wherein the serving cell and the at least one candidate cell belong to the same network node and meet the time alignment error (TAE) requirement.

19. A user equipment (UE) comprising: At least one memory; and At least one processor, coupled to and configured to enable the UE to: Receive reconfiguration messages from network nodes, including L1 / L2-triggered mobility LTM configurations for one or more candidate cells; and In response to receiving a handover command to the second cell or in response to meeting the conditions for handover to the second cell, the UE switches from its serving cell to the second cell and sets the timing advance TA ID of the UE measurement of the serving cell or the no-reset ID of the serving cell based on the reconfiguration message.

20. The UE of claim 19, wherein, in order to set the TA ID measured by the UE for the serving cell, the at least one processor is configured to cause the UE to perform one or more of the following: In response to receiving the handover command and the second cell being one of the one or more candidate cells, the TA ID value measured by the UE of the serving cell is set to the TA ID value measured by the UE of the second cell as indicated in the LTM configuration; In response to receiving the handover command and the second cell not being one of the candidate cells, the network node receives the TA ID measured by the UE of the second cell and sets the value of the TA ID measured by the UE of the serving cell to the value of the received TA ID measured by the UE of the second cell. and In response to the condition of handover to the second cell being met, the TA ID measured by the UE in the second cell is received from the network node and the value of the TA ID measured by the UE in the serving cell is set to the value of the TA ID measured by the UE in the second cell.

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